Stem Cell Treatment for Autism

Stem Cell Treatments for Autism are currently available at ASCI

Stem Cell Therapy for Autism Stem Cell Treatment  Autism

Autism Background:

About a third to a half of individuals with autism do not develop enough natural speech to meet their daily communication needs. Differences in communication may be present from the first year of life, and may include delayed onset of babbling, unusual gestures, diminished responsiveness, and vocal patterns that are not synchronized with the caregiver. In the second and third years, autistic children have less frequent and less diverse babbling, consonants, words, and word combinations; their gestures are less often integrated with words. Autistic children are less likely to make requests or share experiences, and are more likely to simply repeat others' words (echolalia) or reverse pronouns. Joint attention seems to be necessary for functional speech, and deficits in joint attention seem to distinguish infants with ASD. for example, they may look at a pointing hand instead of the pointed-at object, and they consistently fail to point at objects in order to comment on or share an experience. Autistic children may have difficulty with imaginative play and with developing symbols into language.

Repetitive behavior

Forms of repetitive or restricted behavior (RBS-R):

  • Stereotypy is repetitive movement, such as hand flapping, making sounds, head rolling, or body rocking.
  • Compulsive behavior is intended and appears to follow rules, such as arranging objects in stacks or lines.
  • Sameness is resistance to change; for example, insisting that the furniture not be moved or refusing to be interrupted.
  • Ritualistic behavior involves an unvarying pattern of daily activities, such as an unchanging menu or a dressing ritual. This is closely associated with sameness and an independent validation has suggested combining the two factors.
  • Restricted behavior is limited in focus, interest, or activity, such as preoccupation with a single television program, toy, or game.
  • Self-injury includes movements that injure or can injure the person, such as eye poking, skin picking, hand biting, and head banging. A 2007 study reported that self-injury at some point affected about 30% of children with ASD.

No single repetitive or self-injurious behavior seems to be specific to autism, but only autism appears to have an elevated pattern of occurrence and severity of these behaviors.

 

Autism Case Study - STEM CELL AUTISM TREATMENT

 

 

Autism treatment studies and stem cell protocols:

 

Related Articles Stereotyped fetal brain disorganization is induced by hypoxia and requires lysophosphatidic acid receptor 1 (LPA1) signaling. Proc Natl Acad Sci U S A. 2011 Sep 13;108(37):15444-9 Authors: Herr KJ, Herr DR, Lee CW, Noguchi K, Chun J Abstract Fetal hypoxia is a common risk factor that has been associated with a range of CNS disorders including epilepsy, schizophrenia, and autism. Cellular and molecular mechanisms through which hypoxia may damage the developing brain are incompletely understood but are likely to involve disruption of the laminar organization of the cerebral cortex. Lysophosphatidic acid (LPA) is a bioactive lipid capable of cortical influences via one or more of six cognate G protein-coupled receptors, LPA(1-6), several of which are enriched in fetal neural progenitor cells (NPCs). Here we report that fetal hypoxia induces cortical disruption via increased LPA(1) signaling involving stereotyped effects on NPCs: N-cadherin disruption, displacement of mitotic NPCs, and impaired neuronal migration, as assessed both ex vivo and in vivo. Importantly, genetic removal or pharmacological inhibition of LPA(1) prevented the occurrence of these hypoxia-induced phenomena. Hypoxia resulted in overactivation of LPA(1) through selective inhibition of G protein-coupled receptor kinase 2 expression and activation of downstream pathways including G(αi) and Ras-related C3 botulinum toxin substrate 1. These data identify stereotyped and selective hypoxia-induced cerebral cortical disruption requiring LPA(1) signaling, inhibition of which can reduce or prevent disease-associated sequelae, and may take us closer to therapeutic treatment of fetal hypoxia-induced CNS disorders and possibly other forms of hypoxic injury. PMID: 21878565 [PubMed - indexed for MEDLINE]
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Related Articles RNA-Seq of human neurons derived from iPS cells reveals candidate long non-coding RNAs involved in neurogenesis and neuropsychiatric disorders. PLoS One. 2011;6(9):e23356 Authors: Lin M, Pedrosa E, Shah A, Hrabovsky A, Maqbool S, Zheng D, Lachman HM Abstract Genome-wide expression analysis using next generation sequencing (RNA-Seq) provides an opportunity for in-depth molecular profiling of fundamental biological processes, such as cellular differentiation and malignant transformation. Differentiating human neurons derived from induced pluripotent stem cells (iPSCs) provide an ideal system for RNA-Seq since defective neurogenesis caused by abnormalities in transcription factors, DNA methylation, and chromatin modifiers lie at the heart of some neuropsychiatric disorders. As a preliminary step towards applying next generation sequencing using neurons derived from patient-specific iPSCs, we have carried out an RNA-Seq analysis on control human neurons. Dramatic changes in the expression of coding genes, long non-coding RNAs (lncRNAs), pseudogenes, and splice isoforms were seen during the transition from pluripotent stem cells to early differentiating neurons. A number of genes that undergo radical changes in expression during this transition include candidates for schizophrenia (SZ), bipolar disorder (BD) and autism spectrum disorders (ASD) that function as transcription factors and chromatin modifiers, such as POU3F2 and ZNF804A, and genes coding for cell adhesion proteins implicated in these conditions including NRXN1 and NLGN1. In addition, a number of novel lncRNAs were found to undergo dramatic changes in expression, one of which is HOTAIRM1, a regulator of several HOXA genes during myelopoiesis. The increase we observed in differentiating neurons suggests a role in neurogenesis as well. Finally, several lncRNAs that map near SNPs associated with SZ in genome wide association studies also increase during neuronal differentiation, suggesting that these novel transcripts may be abnormally regulated in a subgroup of patients. PMID: 21915259 [PubMed - indexed for MEDLINE]
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Related Articles Modeling psychiatric disorders through reprogramming. Dis Model Mech. 2012 Jan;5(1):26-32 Authors: Brennand KJ, Gage FH Abstract Psychiatric disorders, including autism spectrum disorders and schizophrenia, are extremely heritable complex genetic neurodevelopmental disorders. It is now possible to directly reprogram fibroblasts from psychiatric patients into human induced pluripotent stem cells (hiPSCs) and subsequently differentiate these disorder-specific hiPSCs into neurons. This means that researchers can generate nearly limitless quantities of live human neurons with genetic backgrounds that are known to result in psychiatric disorders, without knowing which genes are interacting to produce the disease state in each patient. With these new human-cell-based models, scientists can investigate the precise cell types that are affected in these disorders and elucidate the cellular and molecular defects that contribute to disease initiation and progression. Here, we present a short review of experiments using hiPSCs and other sophisticated in vitro approaches to study the pathways underlying psychiatric disorders. PMID: 21954066 [PubMed - indexed for MEDLINE]
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Related Articles Isogenic pairs of wild type and mutant induced pluripotent stem cell (iPSC) lines from Rett syndrome patients as in vitro disease model. PLoS One. 2011;6(9):e25255 Authors: Ananiev G, Williams EC, Li H, Chang Q Abstract Rett syndrome (RTT) is an autism spectrum developmental disorder caused by mutations in the X-linked methyl-CpG binding protein 2 (MECP2) gene. Excellent RTT mouse models have been created to study the disease mechanisms, leading to many important findings with potential therapeutic implications. These include the identification of many MeCP2 target genes, better understanding of the neurobiological consequences of the loss- or mis-function of MeCP2, and drug testing in RTT mice and clinical trials in human RTT patients. However, because of potential differences in the underlying biology between humans and common research animals, there is a need to establish cell culture-based human models for studying disease mechanisms to validate and expand the knowledge acquired in animal models. Taking advantage of the nonrandom pattern of X chromosome inactivation in female induced pluripotent stem cells (iPSC), we have generated isogenic pairs of wild type and mutant iPSC lines from several female RTT patients with common and rare RTT mutations. R294X (arginine 294 to stop codon) is a common mutation carried by 5-6% of RTT patients. iPSCs carrying the R294X mutation has not been studied. We differentiated three R294X iPSC lines and their isogenic wild type control iPSC into neurons with high efficiency and consistency, and observed characteristic RTT pathology in R294X neurons. These isogenic iPSC lines provide unique resources to the RTT research community for studying disease pathology, screening for novel drugs, and testing toxicology. PMID: 21966470 [PubMed - indexed for MEDLINE]
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Related Articles A complex between contactin-1 and the protein tyrosine phosphatase PTPRZ controls the development of oligodendrocyte precursor cells. Proc Natl Acad Sci U S A. 2011 Oct 18;108(42):17498-503 Authors: Lamprianou S, Chatzopoulou E, Thomas JL, Bouyain S, Harroch S Abstract The six members of the contactin (CNTN) family of neural cell adhesion molecules are involved in the formation and maintenance of the central nervous system (CNS) and have been linked to mental retardation and neuropsychiatric disorders such as autism. Five of the six CNTNs bind to the homologous receptor protein tyrosine phosphatases gamma (PTPRG) and zeta (PTPRZ), but the biological roles of these interactions remain unclear. We report here the cocrystal structure of the carbonic anhydrase-like domain of PTPRZ bound to tandem Ig repeats of CNTN1 and combine these structural data with binding assays to show that PTPRZ binds specifically to CNTN1 expressed at the surface of oligodendrocyte precursor cells. Furthermore, analyses of glial cell populations in wild-type and PTPRZ-deficient mice show that the binding of PTPRZ to CNTN1 expressed at the surface of oligodendrocyte precursor cells inhibits their proliferation and promotes their development into mature oligodendrocytes. Overall, these results implicate the PTPRZ/CNTN1 complex as a previously unknown modulator of oligodendrogenesis. PMID: 21969550 [PubMed - indexed for MEDLINE]
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Related Articles Chromosome 1p21.3 microdeletions comprising DPYD and MIR137 are associated with intellectual disability. J Med Genet. 2011 Dec;48(12):810-8 Authors: Willemsen MH, Vallès A, Kirkels LA, Mastebroek M, Olde Loohuis N, Kos A, Wissink-Lindhout WM, de Brouwer AP, Nillesen WM, Pfundt R, Holder-Espinasse M, Vallée L, Andrieux J, Coppens-Hofman MC, Rensen H, Hamel BC, van Bokhoven H, Aschrafi A, Kleefstra T Abstract BACKGROUND: MicroRNAs (miRNAs) are non-coding gene transcripts involved in post-transcriptional regulation of genes. Recent studies identified miRNAs as important regulators of learning and memory in model organisms. So far, no mutations in specific miRNA genes have been associated with impaired cognitive functions. METHODS AND RESULTS: In three sibs and two unrelated patients with intellectual disability (ID), overlapping 1p21.3 deletions were detected by genome-wide array analysis. The shortest region of overlap included dihydropyrimidine dehydrogenase (DPYD) and microRNA 137 (MIR137). DPYD is involved in autosomal recessive dihydropyrimidine dehydrogenase deficiency. Hemizygous DPYD deletions were previously suggested to contribute to a phenotype with autism spectrum disorder and speech delay. Interestingly, the mature microRNA transcript microRNA-137 (miR-137) was recently shown to be involved in modulating neurogenesis in adult murine neuronal stem cells. Therefore, this study investigated the possible involvement of MIR137 in the 1p21.3-deletion phenotype. The patients displayed a significantly decreased expression of both precursor and mature miR-137 levels, as well as significantly increased expression of the validated downstream targets microphthalmia-associated transcription factor (MITF) and Enhancer of Zeste, Drosophila, Homologue 2 (EZH2), and the newly identified target Kruppel-like factor 4 (KLF4). The study also demonstrated significant enrichment of miR-137 at the synapses of cortical and hippocampal neurons, suggesting a role of miR-137 in regulating local synaptic protein synthesis machinery. CONCLUSIONS: This study showed that dosage effects of MIR137 are associated with 1p21.3 microdeletions and may therefore contribute to the ID phenotype in patients with deletions harbouring this miRNA. A local effect at the synapse might be responsible. PMID: 22003227 [PubMed - indexed for MEDLINE]
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Related Articles Epigenetic characterization of the FMR1 gene and aberrant neurodevelopment in human induced pluripotent stem cell models of fragile X syndrome. PLoS One. 2011;6(10):e26203 Authors: Sheridan SD, Theriault KM, Reis SA, Zhou F, Madison JM, Daheron L, Loring JF, Haggarty SJ Abstract Fragile X syndrome (FXS) is the most common inherited cause of intellectual disability. In addition to cognitive deficits, FXS patients exhibit hyperactivity, attention deficits, social difficulties, anxiety, and other autistic-like behaviors. FXS is caused by an expanded CGG trinucleotide repeat in the 5' untranslated region of the Fragile X Mental Retardation (FMR1) gene leading to epigenetic silencing and loss of expression of the Fragile X Mental Retardation protein (FMRP). Despite the known relationship between FMR1 CGG repeat expansion and FMR1 silencing, the epigenetic modifications observed at the FMR1 locus, and the consequences of the loss of FMRP on human neurodevelopment and neuronal function remain poorly understood. To address these limitations, we report on the generation of induced pluripotent stem cell (iPSC) lines from multiple patients with FXS and the characterization of their differentiation into post-mitotic neurons and glia. We show that clones from reprogrammed FXS patient fibroblast lines exhibit variation with respect to the predominant CGG-repeat length in the FMR1 gene. In two cases, iPSC clones contained predominant CGG-repeat lengths shorter than measured in corresponding input population of fibroblasts. In another instance, reprogramming a mosaic patient having both normal and pre-mutation length CGG repeats resulted in genetically matched iPSC clonal lines differing in FMR1 promoter CpG methylation and FMRP expression. Using this panel of patient-specific, FXS iPSC models, we demonstrate aberrant neuronal differentiation from FXS iPSCs that is directly correlated with epigenetic modification of the FMR1 gene and a loss of FMRP expression. Overall, these findings provide evidence for a key role for FMRP early in human neurodevelopment prior to synaptogenesis and have implications for modeling of FXS using iPSC technology. By revealing disease-associated cellular phenotypes in human neurons, these iPSC models will aid in the discovery of novel therapeutics for FXS and other autism-spectrum disorders sharing common pathophysiology. PMID: 22022567 [PubMed - indexed for MEDLINE]
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Related Articles Regulable neural progenitor-specific Tsc1 loss yields giant cells with organellar dysfunction in a model of tuberous sclerosis complex. Proc Natl Acad Sci U S A. 2011 Nov 8;108(45):E1070-9 Authors: Goto J, Talos DM, Klein P, Qin W, Chekaluk YI, Anderl S, Malinowska IA, Di Nardo A, Bronson RT, Chan JA, Vinters HV, Kernie SG, Jensen FE, Sahin M, Kwiatkowski DJ Abstract Tuberous sclerosis complex (TSC) is a multiorgan genetic disease in which brain involvement causes epilepsy, intellectual disability, and autism. The hallmark pathological finding in TSC is the cerebral cortical tuber and its unique constituent, giant cells. However, an animal model that replicates giant cells has not yet been described. Here, we report that mosaic induction of Tsc1 loss in neural progenitor cells in Tsc1(cc) Nestin-rtTA(+) TetOp-cre(+) embryos by doxycycline leads to multiple neurological symptoms, including severe epilepsy and premature death. Strikingly, Tsc1-null neural progenitor cells develop into highly enlarged giant cells with enlarged vacuoles. We found that the vacuolated giant cells had multiple signs of organelle dysfunction, including markedly increased mitochondria, aberrant lysosomes, and elevated cellular stress. We found similar vacuolated giant cells in human tuber specimens. Postnatal rapamycin treatment completely reversed these phenotypes and rescued the mutants from epilepsy and premature death, despite prenatal onset of Tsc1 loss and mTOR complex 1 activation in the developing brain. This TSC brain model provides insights into the pathogenesis and organelle dysfunction of giant cells, as well as epilepsy control in patients with TSC. PMID: 22025691 [PubMed - indexed for MEDLINE]
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Related Articles Neurexins and neuroligins: recent insights from invertebrates. Mol Neurobiol. 2011 Dec;44(3):426-40 Authors: Knight D, Xie W, Boulianne GL Abstract During brain development, each neuron must find and synapse with the correct pre- and postsynaptic partners. The complexity of these connections and the relatively large distances some neurons must send their axons to find the correct partners makes studying brain development one of the most challenging, and yet fascinating disciplines in biology. Furthermore, once the initial connections have been made, the neurons constantly remodel their dendritic and axonal arbours in response to changing demands. Neurexin and neuroligin are two cell adhesion molecules identified as important regulators of this process. The importance of these genes in the development and modulation of synaptic connectivity is emphasised by the observation that mutations in these genes in humans have been associated with cognitive disorders such as Autism spectrum disorders, Tourette syndrome and Schizophrenia. The present review will discuss recent advances in our understanding of the role of these genes in synaptic development and modulation, and in particular, we will focus on recent work in invertebrate models, and how these results relate to studies in mammals. PMID: 22037798 [PubMed - indexed for MEDLINE]
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Related Articles Cellular reprogramming: recent advances in modeling neurological diseases. J Neurosci. 2011 Nov 9;31(45):16070-5 Authors: Ming GL, Brüstle O, Muotri A, Studer L, Wernig M, Christian KM Abstract The remarkable advances in cellular reprogramming have made it possible to generate a renewable source of human neurons from fibroblasts obtained from skin samples of neonates and adults. As a result, we can now investigate the etiology of neurological diseases at the cellular level using neuronal populations derived from patients, which harbor the same genetic mutations thought to be relevant to the risk for pathology. Therapeutic implications include the ability to establish new humanized disease models for understanding mechanisms, conduct high-throughput screening for novel biogenic compounds to reverse or prevent the disease phenotype, identify and engineer genetic rescue of causal mutations, and develop patient-specific cellular replacement strategies. Although this field offers enormous potential for understanding and treating neurological disease, there are still many issues that must be addressed before we can fully exploit this technology. Here we summarize several recent studies presented at a symposium at the 2011 annual meeting of the Society for Neuroscience, which highlight innovative approaches to cellular reprogramming and how this revolutionary technique is being refined to model neurodevelopmental and neurodegenerative diseases, such as autism spectrum disorders, schizophrenia, familial dysautonomia, and Alzheimer's disease. PMID: 22072658 [PubMed - indexed for MEDLINE]
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Related Articles Aberrant T-lymphocyte development and function in mice overexpressing human soluble amyloid precursor protein-α: implications for autism. FASEB J. 2012 Mar;26(3):1040-51 Authors: Bailey AR, Hou H, Obregon DF, Tian J, Zhu Y, Zou Q, Nikolic WV, Bengtson M, Mori T, Murphy T, Tan J Abstract Abnormalities in T-lymphocyte populations and function are observed in autism. Soluble amyloid precursor protein α (sAPP-α) is elevated in some patients with autism and is known to be produced by immune cells. In light of the well-established role of sAPP-α in proliferation, growth, and survival of neurons, we hypothesized an analogous role in the immune system. Thus, we explored whether sAPP-α could modulate immune development and function, especially aspects of the pinnacle cell of the adaptive arm of the immune system: the T cell. To do this, we generated mice overexpressing human sAPP-α and characterized elements of T-cell development, signal transduction, cytokine production, and innate/adaptive immune functions. Here, we report that transgenic sAPP-α-overexpressing (TgsAPP-α) mice displayed increased proportions of CD8(+) T cells, while effector memory T cells were decreased in the thymus. Overall apoptotic signal transduction was decreased in the thymus, an effect that correlated with dramatic elevations in Notch1 activation; while active-caspase-3/total-caspase-3 and Bax/Bcl-2 ratios were decreased. Greater levels of IFN-γ, IL-2, and IL-4 were observed after ex vivo challenge of TgsAPP-α mouse splenocytes with T-cell mitogen. Finally, after immunization, splenocytes from TgsAPP-α mice displayed decreased levels IFN-γ, IL-2, and IL-4, as well as suppressed ZAP70 activation, after recall antigen stimulation. Given elevated levels of circulating sAPP-α in some patients with autism, sAPP-α could potentially drive aspects of immune dysfunction observed in these patients, including dysregulated T-cell apoptosis, aberrant PI3K/AKT signaling, cytokine alterations, and impaired T-cell recall stimulation. PMID: 22085641 [PubMed - indexed for MEDLINE]
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Related Articles Rett syndrome mutation MeCP2 T158A disrupts DNA binding, protein stability and ERP responses. Nat Neurosci. 2012 Feb;15(2):274-83 Authors: Goffin D, Allen M, Zhang L, Amorim M, Wang IT, Reyes AR, Mercado-Berton A, Ong C, Cohen S, Hu L, Blendy JA, Carlson GC, Siegel SJ, Greenberg ME, Zhou Z Abstract Mutations in the MECP2 gene cause the autism spectrum disorder Rett syndrome (RTT). One of the most common MeCP2 mutations associated with RTT occurs at threonine 158, converting it to methionine (T158M) or alanine (T158A). To understand the role of T158 mutations in the pathogenesis of RTT, we generated knockin mice that recapitulate the MeCP2 T158A mutation. We found a causal role for T158A mutation in the development of RTT-like phenotypes, including developmental regression, motor dysfunction, and learning and memory deficits. These phenotypes resemble those present in Mecp2 null mice and manifest through a reduction in MeCP2 binding to methylated DNA and a decrease in MeCP2 protein stability. The age-dependent development of event-related neuronal responses was disrupted by MeCP2 mutation, suggesting that impaired neuronal circuitry underlies the pathogenesis of RTT and that assessment of event-related potentials (ERPs) may serve as a biomarker for RTT and treatment evaluation. PMID: 22119903 [PubMed - indexed for MEDLINE]
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Related Articles Using iPSC-derived neurons to uncover cellular phenotypes associated with Timothy syndrome. Nat Med. 2011 Dec;17(12):1657-62 Authors: Paşca SP, Portmann T, Voineagu I, Yazawa M, Shcheglovitov A, Paşca AM, Cord B, Palmer TD, Chikahisa S, Nishino S, Bernstein JA, Hallmayer J, Geschwind DH, Dolmetsch RE Abstract Monogenic neurodevelopmental disorders provide key insights into the pathogenesis of disease and help us understand how specific genes control the development of the human brain. Timothy syndrome is caused by a missense mutation in the L-type calcium channel Ca(v)1.2 that is associated with developmental delay and autism. We generated cortical neuronal precursor cells and neurons from induced pluripotent stem cells derived from individuals with Timothy syndrome. Cells from these individuals have defects in calcium (Ca(2+)) signaling and activity-dependent gene expression. They also show abnormalities in differentiation, including decreased expression of genes that are expressed in lower cortical layers and in callosal projection neurons. In addition, neurons derived from individuals with Timothy syndrome show abnormal expression of tyrosine hydroxylase and increased production of norepinephrine and dopamine. This phenotype can be reversed by treatment with roscovitine, a cyclin-dependent kinase inhibitor and atypical L-type-channel blocker. These findings provide strong evidence that Ca(v)1.2 regulates the differentiation of cortical neurons in humans and offer new insights into the causes of autism in individuals with Timothy syndrome. PMID: 22120178 [PubMed - indexed for MEDLINE]
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Related Articles Rett syndrome induced pluripotent stem cell-derived neurons reveal novel neurophysiological alterations. Mol Psychiatry. 2012 Dec;17(12):1261-71 Authors: Farra N, Zhang WB, Pasceri P, Eubanks JH, Salter MW, Ellis J Abstract Rett syndrome (RTT) is a neurodevelopmental autism spectrum disorder caused by mutations in the methyl-CpG-binding protein 2 (MECP2) gene. Here, we describe the first characterization and neuronal differentiation of induced pluripotent stem (iPS) cells derived from Mecp2-deficient mice. Fully reprogrammed wild-type (WT) and heterozygous female iPS cells express endogenous pluripotency markers, reactivate the X-chromosome and differentiate into the three germ layers. We directed iPS cells to produce glutamatergic neurons, which generated action potentials and formed functional excitatory synapses. iPS cell-derived neurons from heterozygous Mecp2(308) mice showed defects in the generation of evoked action potentials and glutamatergic synaptic transmission, as previously reported in brain slices. Further, we examined electrophysiology features not yet studied with the RTT iPS cell system and discovered that MeCP2-deficient neurons fired fewer action potentials, and displayed decreased action potential amplitude, diminished peak inward currents and higher input resistance relative to WT iPS-derived neurons. Deficiencies in action potential firing and inward currents suggest that disturbed Na(+) channel function may contribute to the dysfunctional RTT neuronal network. These phenotypes were additionally confirmed in neurons derived from independent WT and hemizygous mutant iPS cell lines, indicating that these reproducible deficits are attributable to MeCP2 deficiency. Taken together, these results demonstrate that neuronally differentiated MeCP2-deficient iPS cells recapitulate deficits observed previously in primary neurons, and these identified phenotypes further illustrate the requirement of MeCP2 in neuronal development and/or in the maintenance of normal function. By validating the use of iPS cells to delineate mechanisms underlying RTT pathogenesis, we identify deficiencies that can be targeted for in vitro translational screens. PMID: 22230884 [PubMed - indexed for MEDLINE]
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Related Articles Derivation of autism spectrum disorder-specific induced pluripotent stem cells from peripheral blood mononuclear cells. Neurosci Lett. 2012 May 10;516(1):9-14 Authors: DeRosa BA, Van Baaren JM, Dubey GK, Lee JM, Cuccaro ML, Vance JM, Pericak-Vance MA, Dykxhoorn DM Abstract Induced pluripotent stem cells (iPSCs) hold tremendous potential both as a biological tool to uncover the pathophysiology of disease by creating relevant cell models and as a source of stem cells for cell-based therapeutic applications. Typically, iPSCs have been derived by the transgenic overexpression of transcription factors associated with progenitor cell or stem cell function in fibroblasts derived from skin biopsies. However, the need for skin punch biopsies to derive fibroblasts for reprogramming can present a barrier to study participation among certain populations of individuals, including children with autism spectrum disorders (ASDs). In addition, the acquisition of skin punch biopsies in non-clinic settings presents a challenge. One potential mechanism to avoid these limitations would be the use of peripheral blood mononuclear cells (PBMCs) as the source of the cells for reprogramming. In this article we describe, for the first time, the derivation of iPSC lines from PBMCs isolated from the whole blood of autistic children, and their subsequent differentiation in GABAergic neurons. PMID: 22405972 [PubMed - indexed for MEDLINE]
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Related Articles Reduction of BDNF expression in Fmr1 knockout mice worsens cognitive deficits but improves hyperactivity and sensorimotor deficits. Genes Brain Behav. 2012 Jul;11(5):513-23 Authors: Uutela M, Lindholm J, Louhivuori V, Wei H, Louhivuori LM, Pertovaara A, Akerman K, Castrén E, Castrén ML Abstract Fragile X syndrome (FXS) is a common cause of inherited intellectual disability and a well-characterized form of autism spectrum disorder. As brain-derived neurotrophic factor (BDNF) is implicated in the pathophysiology of FXS we examined the effects of reduced BDNF expression on the behavioral phenotype of an animal model of FXS, Fmr1 knockout (KO) mice, crossed with mice carrying a deletion of one copy of the Bdnf gene (Bdnf(+/-)). Fmr1 KO mice showed age-dependent alterations in hippocampal BDNF expression that declined after the age of 4 months compared to wild-type controls. Mild deficits in water maze learning in Bdnf(+/-) and Fmr1 KO mice were exaggerated and contextual fear learning significantly impaired in double transgenics. Reduced BDNF expression did not alter basal nociceptive responses or central hypersensitivity in Fmr1 KO mice. Paradoxically, the locomotor hyperactivity and deficits in sensorimotor learning and startle responses characteristic of Fmr1 KO mice were ameliorated by reducing BNDF, suggesting changes in simultaneously and in parallel working hippocampus-dependent and striatum-dependent systems. Furthermore, the obesity normally seen in Bdnf(+/-) mice was eliminated by the absence of fragile X mental retardation protein 1 (FMRP). Reduced BDNF decreased the survival of newborn cells in the ventral part of the hippocampus both in the presence and absence of FMRP. Since a short neurite phenotype characteristic of newborn cells lacking FMRP was not found in cells derived from double mutant mice, changes in neuronal maturation likely contributed to the behavioral phenotype. Our results show that the absence of FMRP modifies the diverse effects of BDNF on the FXS phenotype. PMID: 22435671 [PubMed - indexed for MEDLINE]
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Related Articles All-trans-retinoid acid induces the differentiation of encapsulated mouse embryonic stem cells into GABAergic neurons. Differentiation. 2012 Jun;83(5):233-41 Authors: Addae C, Yi X, Gernapudi R, Cheng H, Musto A, Martinez-Ceballos E Abstract Embryonic stem (ES) cells are pluripotent cells that can differentiate into all three main germ layers: endoderm, mesoderm, and ectoderm. Although a number of methods have been developed to differentiate ES cells into neuronal phenotypes such as sensory and motor neurons, the efficient generation of GABAergic interneurons from ES cells still presents an ongoing challenge. Because the main output of inhibitory GABAergic interneurons is the gamma-aminobutyric-acid (GABA), a neurotransmitter whose controlled homeostasis is required for normal brain function, the efficient generation in culture of functional interneurons may have future implications on the treatment of neurological disorders such as epilepsy, autism, and schizophrenia. The goal of this work was to examine the generation of GABAergic neurons from mouse ES cells by comparing an embryoid body-based methodology versus a hydrogel-based encapsulation protocol that involves the use of all-trans-retinoid acid (RA). We observed that (1) there was a 2-fold increase in neuronal differentiation in encapsulated versus non-encapsulated cells and (2) there was an increase in the specificity for interneuronal differentiation in encapsulated cells, as assessed by mRNA expression and electrophysiology approaches. Furthermore, our results indicate that most of the neurons obtained from encapsulated mouse ES cells are GABA-positive (∼87%). Thus, these results suggest that combining encapsulation of ES cells and RA treatment provide a more efficient and scalable differentiation strategy for the generation in culture of functional GABAergic interneurons. This technology may have implications for future cell replacement therapies and the treatment of CNS disorders. PMID: 22466603 [PubMed - indexed for MEDLINE]
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Related Articles Modeling psychiatric disorders at the cellular and network levels. Mol Psychiatry. 2012 Dec;17(12):1239-53 Authors: Brennand KJ, Simone A, Tran N, Gage FH Abstract Although psychiatric disorders such as autism spectrum disorders, schizophrenia and bipolar disorder affect a number of brain regions and produce a complex array of clinical symptoms, basic phenotypes likely exist at the level of single neurons and simple networks. Being highly heritable, it is hypothesized that these disorders are amenable to cell-based studies in vitro. Using induced pluripotent stem cell-derived neurons and/or induced neurons from fibroblasts, limitless numbers of live human neurons can now be generated from patients with a genetic background permissive to the disease state. We predict that cell-based studies will ultimately contribute to our understanding of the initiation, progression and treatment of these psychiatric disorders. PMID: 22472874 [PubMed - indexed for MEDLINE]
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Related Articles Neurodevelopmental model of schizophrenia: update 2012. Mol Psychiatry. 2012 Dec;17(12):1228-38 Authors: Rapoport JL, Giedd JN, Gogtay N Abstract The neurodevelopmental model of schizophrenia, which posits that the illness is the end state of abnormal neurodevelopmental processes that started years before the illness onset, is widely accepted, and has long been dominant for childhood-onset neuropsychiatric disorders. This selective review updates our 2005 review of recent studies that have impacted, or have the greatest potential to modify or extend, the neurodevelopmental model of schizophrenia. Longitudinal whole-population studies support a dimensional, rather than categorical, concept of psychosis. New studies suggest that placental pathology could be a key measure in future prenatal high-risk studies. Both common and rare genetic variants have proved surprisingly diagnostically nonspecific, and copy number variants (CNVs) associated with schizophrenia are often also associated with autism, epilepsy and intellectual deficiency. Large post-mortem gene expression studies and prospective developmental multi-modal brain imaging studies are providing critical data for future clinical and high-risk developmental brain studies. Whether there can be greater molecular specificity for phenotypic characterization is a subject of current intense study and debate, as is the possibility of neuronal phenotyping using human pluripotent-inducible stem cells. Biological nonspecificity, such as in timing or nature of early brain development, carries the possibility of new targets for broad preventive treatments. PMID: 22488257 [PubMed - indexed for MEDLINE]
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Related Articles Autism spectrum disorders: is mesenchymal stem cell personalized therapy the future? J Biomed Biotechnol. 2012;2012:480289 Authors: Siniscalco D, Sapone A, Cirillo A, Giordano C, Maione S, Antonucci N Abstract Autism and autism spectrum disorders (ASDs) are heterogeneous neurodevelopmental disorders. They are enigmatic conditions that have their origins in the interaction of genes and environmental factors. ASDs are characterized by dysfunctions in social interaction and communication skills, in addition to repetitive and stereotypic verbal and nonverbal behaviours. Immune dysfunction has been confirmed with autistic children. There are no defined mechanisms of pathogenesis or curative therapy presently available. Indeed, ASDs are still untreatable. Available treatments for autism can be divided into behavioural, nutritional, and medical approaches, although no defined standard approach exists. Nowadays, stem cell therapy represents the great promise for the future of molecular medicine. Among the stem cell population, mesenchymal stem cells (MSCs) show probably best potential good results in medical research. Due to the particular immune and neural dysregulation observed in ASDs, mesenchymal stem cell transplantation could offer a unique tool to provide better resolution for this disease. PMID: 22496609 [PubMed - indexed for MEDLINE]
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Related Articles China's stem-cell rules go unheeded. Nature. 2012 Apr 12;484(7393):149-50 Authors: Cyranoski D PMID: 22498601 [PubMed - indexed for MEDLINE]
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Related Articles Fragile X Protein is required for inhibition of insulin signaling and regulates glial-dependent neuroblast reactivation in the developing brain. Brain Res. 2012 Jun 26;1462:151-61 Authors: Callan MA, Clements N, Ahrendt N, Zarnescu DC Abstract Fragile X syndrome (FXS) is the most common form of inherited mental disability and known cause of autism. It is caused by loss of function for the RNA binding protein FMRP, which has been demonstrated to regulate several aspects of RNA metabolism including transport, stability and translation at synapses. Recently, FMRP has been implicated in neural stem cell proliferation and differentiation both in cultured neurospheres as well as in vivo mouse and fly models of FXS. We have previously shown that FMRP deficient Drosophila neuroblasts upregulate Cyclin E, prematurely exit quiescence, and overproliferate to generate on average 16% more neurons. Here we further investigate FMRP's role during early development using the Drosophila larval brain as a model. Using tissue specific RNAi we find that FMRP is required sequentially, first in neuroblasts and then in glia, to regulate exit from quiescence as measured by Cyclin E expression in the brain. Furthermore, we tested the hypothesis that FMRP controls brain development by regulating the insulin signaling pathway, which has been recently shown to regulate neuroblast exit from quiescence. Our data indicate that phosphoAkt, a readout of insulin signaling, is upregulated in dFmr1 brains at the time when FMRP is required in glia for neuroblast reactivation. In addition, dFmr1 interacts genetically with dFoxO, a transcriptional regulator of insulin signaling. Our results provide the first evidence that FMRP is required in vivo, in glia for neuroblast reactivation and suggest that it may do so by regulating the output of the insulin signaling pathway. This article is part of a Special Issue entitled: RNA-Binding Proteins. PMID: 22513101 [PubMed - indexed for MEDLINE]
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Related Articles Administration of autologous bone marrow-derived mononuclear cells in children with incurable neurological disorders and injury is safe and improves their quality of life. Cell Transplant. 2012;21 Suppl 1:S79-90 Authors: Sharma A, Gokulchandran N, Chopra G, Kulkarni P, Lohia M, Badhe P, Jacob VC Abstract Neurological disorders such as muscular dystrophy, cerebral palsy, and injury to the brain and spine currently have no known definitive treatments or cures. A study was carried out on 71 children suffering from such incurable neurological disorders and injury. They were intrathecally and intramuscularly administered autologous bone marrow-derived mononuclear cells. Assessment after transplantation showed neurological improvements in muscle power and a shift on assessment scales such as FIM and Brooke and Vignos scale. Further, imaging and electrophysiological studies also showed significant changes in selective cases. On an average follow-up of 15 ± 1 months, overall 97% muscular dystrophy cases showed subjective and functional improvement, with 2 of them also showing changes on MRI and 3 on EMG. One hundred percent of the spinal cord injury cases showed improvement with respect to muscle strength, urine control, spasticity, etc. Eighty-five percent of cases of cerebral palsy cases showed improvements, out of which 75% reported improvement in muscle tone and 50% in speech among other symptoms. Eighty-eight percent of cases of other incurable neurological disorders such as autism, Retts Syndrome, giant axonal neuropathy, etc., also showed improvement. No significant adverse events were noted. The results show that this treatment is safe, efficacious, and also improves the quality of life of children with incurable neurological disorders and injury. PMID: 22507683 [PubMed - indexed for MEDLINE]
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Related Articles Pten deletion in adult hippocampal neural stem/progenitor cells causes cellular abnormalities and alters neurogenesis. J Neurosci. 2012 Apr 25;32(17):5880-90 Authors: Amiri A, Cho W, Zhou J, Birnbaum SG, Sinton CM, McKay RM, Parada LF Abstract Adult neurogenesis persists throughout life in restricted brain regions in mammals and is affected by various physiological and pathological conditions. The tumor suppressor gene Pten is involved in adult neurogenesis and is mutated in a subset of autism patients with macrocephaly; however, the link between the role of PTEN in adult neurogenesis and the etiology of autism has not been studied before. Moreover, the role of hippocampus, one of the brain regions where adult neurogenesis occurs, in development of autism is not clear. Here, we show that ablating Pten in adult neural stem cells in the subgranular zone of hippocampal dentate gyrus results in higher proliferation rate and accelerated differentiation of the stem/progenitor cells, leading to depletion of the neural stem cell pool and increased differentiation toward the astrocytic lineage at later stages. Pten-deleted stem/progenitor cells develop into hypertrophied neurons with abnormal polarity. Additionally, Pten mutant mice have macrocephaly and exhibit impairment in social interactions and seizure activity. Our data reveal a novel function for PTEN in adult hippocampal neurogenesis and indicate a role in the pathogenesis of abnormal social behaviors. PMID: 22539849 [PubMed - indexed for MEDLINE]
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Related Articles Signaling defects in iPSC-derived fragile X premutation neurons. Hum Mol Genet. 2012 Sep 1;21(17):3795-805 Authors: Liu J, Koscielska KA, Cao Z, Hulsizer S, Grace N, Mitchell G, Nacey C, Githinji J, McGee J, Garcia-Arocena D, Hagerman RJ, Nolta J, Pessah IN, Hagerman PJ Abstract Fragile X-associated tremor/ataxia syndrome (FXTAS) is a leading monogenic neurodegenerative disorder affecting premutation carriers of the fragile X (FMR1) gene. To investigate the underlying cellular neuropathology, we produced induced pluripotent stem cell-derived neurons from isogenic subclones of primary fibroblasts of a female premutation carrier, with each subclone bearing exclusively either the normal or the expanded (premutation) form of the FMR1 gene as the active allele. We show that neurons harboring the stably-active, expanded allele (EX-Xa) have reduced postsynaptic density protein 95 protein expression, reduced synaptic puncta density and reduced neurite length. Importantly, such neurons are also functionally abnormal, with calcium transients of higher amplitude and increased frequency than for neurons harboring the normal-active allele. Moreover, a sustained calcium elevation was found in the EX-Xa neurons after glutamate application. By excluding the individual genetic background variation, we have demonstrated neuronal phenotypes directly linked to the FMR1 premutation. Our approach represents a unique isogenic, X-chromosomal epigenetic model to aid the development of targeted therapeutics for FXTAS, and more broadly as a model for the study of common neurodevelopmental (e.g. autism) and neurodegenerative (e.g. Parkinsonism, dementias) disorders. PMID: 22641815 [PubMed - indexed for MEDLINE]
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Related Articles Genetic and functional abnormalities of the melatonin biosynthesis pathway in patients with bipolar disorder. Hum Mol Genet. 2012 Sep 15;21(18):4030-7 Authors: Etain B, Dumaine A, Bellivier F, Pagan C, Francelle L, Goubran-Botros H, Moreno S, Deshommes J, Moustafa K, Le Dudal K, Mathieu F, Henry C, Kahn JP, Launay JM, Mühleisen TW, Cichon S, Bourgeron T, Leboyer M, Jamain S Abstract Patients affected by bipolar disorder (BD) frequently report abnormalities in sleep/wake cycles. In addition, they showed abnormal oscillating melatonin secretion, a key regulator of circadian rhythms and sleep patterns. The acetylserotonin O-methyltransferase (ASMT) is a key enzyme of the melatonin biosynthesis and has recently been associated with psychiatric disorders such as autism spectrum disorders and depression. In this paper, we analysed rare and common variants of ASMT in patients with BD and unaffected control subjects and performed functional analysis of these variants by assaying the ASMT activity in their B-lymphoblastoid cell lines. We sequenced the coding and the regulatory regions of the gene in a discovery sample of 345 patients with BD and 220 controls. We performed an association study on this discovery sample using common variants located in the promoter region and showed that rs4446909 was significantly associated with BD (P= 0.01) and associated with a lower mRNA level (P< 10(-4)) and a lower enzymatic activity (P< 0.05) of ASMT. A replication study and a meta-analysis using 480 independent patients with BD and 672 controls confirmed the significant association between rs4446909 and BD (P= 0.002). These results correlate with the general lower ASMT enzymatic activity observed in patients with BD (P= 0.001) compared with controls. Finally, several deleterious ASMT mutations identified in patients were associated with low ASMT activity (P= 0.01). In this study, we determined how rare and common variations in ASMT might play a role in BD vulnerability and suggest a general role of melatonin as susceptibility factor for BD. PMID: 22694957 [PubMed - indexed for MEDLINE]
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Related Articles Modeling neurodevelopmental disorders using human neurons. Curr Opin Neurobiol. 2012 Oct;22(5):785-90 Authors: Chailangkarn T, Acab A, Muotri AR Abstract The cellular and molecular mechanisms of neurodevelopmental conditions such as autism spectrum disorders have been studied intensively for decades. The unavailability of live patient neurons for research, however, has represented a major obstacle in the elucidation of the disease etiologies. Recently, the development of induced pluripotent stem cell (iPSC) technology allows for the generation of human neurons from somatic cells of patients. We review ongoing studies using iPSCs as an approach to model neurodevelopmental disorders, the promise and caveats of this technique and its potential for drug screening. The reproducible findings of relevant phenotypes in Rett syndrome iPSC-derived neurons suggest that iPSC technology offers a novel and unique opportunity for the understanding of and the development of therapeutics for other autism spectrum disorders. PMID: 22717528 [PubMed - indexed for MEDLINE]
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Related Articles Disrupted ERK signaling during cortical development leads to abnormal progenitor proliferation, neuronal and network excitability and behavior, modeling human neuro-cardio-facial-cutaneous and related syndromes. J Neurosci. 2012 Jun 20;32(25):8663-77 Authors: Pucilowska J, Puzerey PA, Karlo JC, Galán RF, Landreth GE Abstract Genetic disorders arising from copy number variations in the ERK (extracellular signal-regulated kinase) MAP (mitogen-activated protein) kinases or mutations in their upstream regulators that result in neuro-cardio-facial-cutaneous syndromes are associated with developmental abnormalities, cognitive deficits, and autism. We developed murine models of these disorders by deleting the ERKs at the beginning of neurogenesis and report disrupted cortical progenitor generation and proliferation, which leads to altered cytoarchitecture of the postnatal brain in a gene-dose-dependent manner. We show that these changes are due to ERK-dependent dysregulation of cyclin D1 and p27(Kip1), resulting in cell cycle elongation, favoring neurogenic over self-renewing divisions. The precocious neurogenesis causes premature progenitor pool depletion, altering the number and distribution of pyramidal neurons. Importantly, loss of ERK2 alters the intrinsic excitability of cortical neurons and contributes to perturbations in global network activity. These changes are associated with elevated anxiety and impaired working and hippocampal-dependent memory in these mice. This study provides a novel mechanistic insight into the basis of cortical malformation which may provide a potential link to cognitive deficits in individuals with altered ERK activity. PMID: 22723706 [PubMed - indexed for MEDLINE]
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Related Articles RBFOX1 regulates both splicing and transcriptional networks in human neuronal development. Hum Mol Genet. 2012 Oct 1;21(19):4171-86 Authors: Fogel BL, Wexler E, Wahnich A, Friedrich T, Vijayendran C, Gao F, Parikshak N, Konopka G, Geschwind DH Abstract RNA splicing plays a critical role in the programming of neuronal differentiation and, consequently, normal human neurodevelopment, and its disruption may underlie neurodevelopmental and neuropsychiatric disorders. The RNA-binding protein, fox-1 homolog (RBFOX1; also termed A2BP1 or FOX1), is a neuron-specific splicing factor predicted to regulate neuronal splicing networks clinically implicated in neurodevelopmental disease, including autism spectrum disorder (ASD), but only a few targets have been experimentally identified. We used RNA sequencing to identify the RBFOX1 splicing network at a genome-wide level in primary human neural stem cells during differentiation. We observe that RBFOX1 regulates a wide range of alternative splicing events implicated in neuronal development and maturation, including transcription factors, other splicing factors and synaptic proteins. Downstream alterations in gene expression define an additional transcriptional network regulated by RBFOX1 involved in neurodevelopmental pathways remarkably parallel to those affected by splicing. Several of these differentially expressed genes are further implicated in ASD and related neurodevelopmental diseases. Weighted gene co-expression network analysis demonstrates a high degree of connectivity among these disease-related genes, highlighting RBFOX1 as a key factor coordinating the regulation of both neurodevelopmentally important alternative splicing events and clinically relevant neuronal transcriptional programs in the development of human neurons. PMID: 22730494 [PubMed - indexed for MEDLINE]
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Related Articles Cellular reprogramming: a novel tool for investigating autism spectrum disorders. Trends Mol Med. 2012 Aug;18(8):463-71 Authors: Kim KY, Jung YW, Sullivan GJ, Chung L, Park IH Abstract Autism spectrum disorder (ASD) is a neurodevelopmental disorder characterized by impairment in reciprocal social interaction and communication, as well as the manifestation of stereotyped behaviors. Despite much effort, ASDs are not yet fully understood. Advanced genetics and genomics technologies have recently identified novel ASD genes, and approaches using genetically engineered murine models or postmortem human brain have facilitated understanding ASD. Reprogramming somatic cells into induced pluripotent stem cells (iPSCs) provides unprecedented opportunities in generating human disease models. Here, we present an overview of applying iPSCs in developing cellular models for understanding ASD. We also discuss future perspectives in the use of iPSCs as a source of cell therapy and as a screening platform for identifying small molecules with efficacy for alleviating ASD. PMID: 22771169 [PubMed - indexed for MEDLINE]
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Related Articles Modeling an autism risk factor in mice leads to permanent immune dysregulation. Proc Natl Acad Sci U S A. 2012 Jul 31;109(31):12776-81 Authors: Hsiao EY, McBride SW, Chow J, Mazmanian SK, Patterson PH Abstract Increasing evidence highlights a role for the immune system in the pathogenesis of autism spectrum disorder (ASD), as immune dysregulation is observed in the brain, periphery, and gastrointestinal tract of ASD individuals. Furthermore, maternal infection (maternal immune activation, MIA) is a risk factor for ASD. Modeling this risk factor in mice yields offspring with the cardinal behavioral and neuropathological symptoms of human ASD. In this study, we find that offspring of immune-activated mothers display altered immune profiles and function, characterized by a systemic deficit in CD4(+) TCRβ(+) Foxp3(+) CD25(+) T regulatory cells, increased IL-6 and IL-17 production by CD4(+) T cells, and elevated levels of peripheral Gr-1(+) cells. In addition, hematopoietic stem cells from MIA offspring exhibit altered myeloid lineage potential and differentiation. Interestingly, repopulating irradiated control mice with bone marrow derived from MIA offspring does not confer MIA-related immunological deficits, implicating the peripheral environmental context in long-term programming of immune dysfunction. Furthermore, behaviorally abnormal MIA offspring that have been irradiated and transplanted with immunologically normal bone marrow from either MIA or control offspring no longer exhibit deficits in stereotyped/repetitive and anxiety-like behaviors, suggesting that immune abnormalities in MIA offspring can contribute to ASD-related behaviors. These studies support a link between cellular immune dysregulation and ASD-related behavioral deficits in a mouse model of an autism risk factor. PMID: 22802640 [PubMed - indexed for MEDLINE]
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Related Articles Prenatal exposure to valproic acid increases the neural progenitor cell pool and induces macrocephaly in rat brain via a mechanism involving the GSK-3β/β-catenin pathway. Neuropharmacology. 2012 Nov;63(6):1028-41 Authors: Go HS, Kim KC, Choi CS, Jeon SJ, Kwon KJ, Han SH, Lee J, Cheong JH, Ryu JH, Kim CH, Ko KH, Shin CY Abstract Autism is a spectrum of neurodevelopmental disorders characterized by social isolation and lack of interaction. Anatomically, autism patients often show macrocephaly and high neuronal density. To investigate the mechanism underlying the higher neuronal populations seen in ASD, we subcutaneously injected VPA (400 mg/kg) into pregnant Sprague-Dawley rats on E12, an animal model often used in ASD study. Alternatively, cultured rat neural progenitor cells were treated with VPA. Until E18, VPA induced NPC proliferation and delayed neurogenesis in fetal brain, but the subsequent differentiation of NPCs to neurons increased brain neuronal density afterward. Similar findings were observed with NPCs treated with VPA in vitro. At a molecular level, VPA enhanced Wnt1 expression and activated the GSK-3β/β-catenin pathway. Furthermore, inhibition of this pathway attenuated the effects of VPA. The findings of this study suggest that an altered developmental process underlies the macrocephaly and abnormal brain structure observed in the autistic brain. PMID: 22841957 [PubMed - indexed for MEDLINE]
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Related Articles Disease modeling using embryonic stem cells: MeCP2 regulates nuclear size and RNA synthesis in neurons. Stem Cells. 2012 Oct;30(10):2128-39 Authors: Yazdani M, Deogracias R, Guy J, Poot RA, Bird A, Barde YA Abstract Mutations in the gene encoding the methyl-CpG-binding protein MECP2 are the major cause of Rett syndrome, an autism spectrum disorder mainly affecting young females. MeCP2 is an abundant chromatin-associated protein, but how and when its absence begins to alter brain function is still far from clear. Using a stem cell-based system allowing the synchronous differentiation of neuronal progenitors, we found that in the absence of MeCP2, the size of neuronal nuclei fails to increase at normal rates during differentiation. This is accompanied by a marked decrease in the rate of ribonucleotide incorporation, indicating an early role of MeCP2 in regulating total gene transcription, not restricted to selected mRNAs. We also found that the levels of brain-derived neurotrophic factor (BDNF) were decreased in mutant neurons, while those of the presynaptic protein synaptophysin increased at similar rates in wild-type and mutant neurons. By contrast, nuclear size, transcription rates, and BDNF levels remained unchanged in astrocytes lacking MeCP2. Re-expressing MeCP2 in mutant neurons rescued the nuclear size phenotype as well as BDNF levels. These results reveal a new role of MeCP2 in regulating overall RNA synthesis in neurons during the course of their maturation, in line with recent findings indicating a reduced nucleolar size in neurons of the developing brain of mice lacking Mecp2. PMID: 22865604 [PubMed - indexed for MEDLINE]
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Related Articles CDKL5 ensures excitatory synapse stability by reinforcing NGL-1-PSD95 interaction in the postsynaptic compartment and is impaired in patient iPSC-derived neurons. Nat Cell Biol. 2012 Sep;14(9):911-23 Authors: Ricciardi S, Ungaro F, Hambrock M, Rademacher N, Stefanelli G, Brambilla D, Sessa A, Magagnotti C, Bachi A, Giarda E, Verpelli C, Kilstrup-Nielsen C, Sala C, Kalscheuer VM, Broccoli V Abstract Mutations of the cyclin-dependent kinase-like 5 (CDKL5) and netrin-G1 (NTNG1) genes cause a severe neurodevelopmental disorder with clinical features that are closely related to Rett syndrome, including intellectual disability, early-onset intractable epilepsy and autism. We report here that CDKL5 is localized at excitatory synapses and contributes to correct dendritic spine structure and synapse activity. To exert this role, CDKL5 binds and phosphorylates the cell adhesion molecule NGL-1. This phosphorylation event ensures a stable association between NGL-1 and PSD95. Accordingly, phospho-mutant NGL-1 is unable to induce synaptic contacts whereas its phospho-mimetic form binds PSD95 more efficiently and partially rescues the CDKL5-specific spine defects. Interestingly, similarly to rodent neurons, iPSC-derived neurons from patients with CDKL5 mutations exhibit aberrant dendritic spines, thus suggesting a common function of CDKL5 in mice and humans. PMID: 22922712 [PubMed - indexed for MEDLINE]
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Related Articles Allele-biased expression in differentiating human neurons: implications for neuropsychiatric disorders. PLoS One. 2012;7(8):e44017 Authors: Lin M, Hrabovsky A, Pedrosa E, Wang T, Zheng D, Lachman HM Abstract Stochastic processes and imprinting, along with genetic factors, lead to monoallelic or allele-biased gene expression. Stochastic monoallelic expression fine-tunes information processing in immune cells and the olfactory system, and imprinting plays an important role in development. Recent studies suggest that both stochastic events and imprinting may be more widespread than previously considered. We are interested in allele-biased gene expression occurring in the brain because parent-of-origin effects suggestive of imprinting appear to play a role in the transmission of schizophrenia (SZ) and autism spectrum disorders (ASD) in some families. In addition, allele-biased expression could help explain monozygotic (MZ) twin discordance and reduced penetrance. The ability to study allele-biased expression in human neurons has been transformed with the advent of induced pluripotent stem cell (iPSC) technology and next generation sequencing. Using transcriptome sequencing (RNA-Seq) we identified 801 genes in differentiating neurons that were expressed in an allele-biased manner. These included a number of putative SZ and ASD candidates, such as A2BP1 (RBFOX1), ERBB4, NLGN4X, NRG1, NRG3, NRXN1, and NLGN1. Overall, there was a modest enrichment for SZ and ASD candidate genes among those that showed evidence for allele-biased expression (chi-square, p = 0.02). In addition to helping explain MZ twin discordance and reduced penetrance, the capacity to group many candidate genes affecting a variety of molecular and cellular pathways under a common regulatory process - allele-biased expression - could have therapeutic implications. PMID: 22952857 [PubMed - indexed for MEDLINE]
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Related Articles Stem cells and modeling of autism spectrum disorders. Exp Neurol. 2012 Oct 2; Authors: Freitas BC, Trujillo CA, Carromeu C, Yusupova M, Herai RH, Muotri AR Abstract Human neurons, generated from reprogrammed somatic cells isolated from live patients, bring a new perspective on the understanding of Autism Spectrum Disorders (ASD). The new technology can nicely complement other models for basic research and the development of therapeutic compounds aiming to revert or ameliorate the condition. Here, we discuss recent advances on the use of stem cells and other models to study ASDs, as well as their limitations, implications and future perspectives. PMID: 23036599 [PubMed - as supplied by publisher]
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Related Articles Distribution of secretin receptors in the rat central nervous system: an in situ hybridization study. J Mol Neurosci. 2013 May;50(1):172-8 Authors: Tóth ZE, Heinzlmann A, Hashimoto H, Köves K Abstract Secretin shows a wide distribution in the brain. Functional significance of central secretin is stressed since it has been associated with autism and schizophrenia. The presence of the secretin receptor was previously demonstrated in the brain by different methods. Neurons in the cerebellum, hypothalamic paraventricular and supraoptic nuclei, and in the vascular organ of lamina terminalis were shown to express secretin receptor mRNA by using in situ hybridization with digoxigenin-labeled probe. In this work, we used a very sensitive radioactive in situ hybridization technique and systematically mapped the expression of secretin receptor mRNA in the brain. The densest labeling was observed in the nucleus of solitary tract and in the laterodorsal thalamic nucleus, where decreasing number of receptors was seen in the vascular organ of lamina terminalis, and the lateral habenular complex, and then in the supraoptic nucleus. Only a few scattered labeled cells were observed in the median frontal gyrus, entorhinal cortex, hypothalamic paraventricular nucleus, perifornical region, lateral hypothalamic area, head of the caudate nucleus, spinal trigeminal nucleus, and cerebellum. Secretin receptor mRNA showed a far wider distribution than was known before, suggesting a more significant functional relevance than thought earlier. PMID: 23065333 [PubMed - indexed for MEDLINE]
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Related Articles [Autism, stem cells, and magical powder]. Rev Med Suisse. 2012 Sep 19;8(354):1795 Authors: Mauron A PMID: 23097920 [PubMed - indexed for MEDLINE]
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Related Articles Intranasal treatment of central nervous system dysfunction in humans. Pharm Res. 2013 Oct;30(10):2475-84 Authors: Chapman CD, Frey WH, Craft S, Danielyan L, Hallschmid M, Schiöth HB, Benedict C Abstract One of the most challenging problems facing modern medicine is how to deliver a given drug to a specific target at the exclusion of other regions. For example, a variety of compounds have beneficial effects within the central nervous system (CNS), but unwanted side effects in the periphery. For such compounds, traditional oral or intravenous drug delivery fails to provide benefit without cost. However, intranasal delivery is emerging as a noninvasive option for delivering drugs to the CNS with minimal peripheral exposure. Additionally, this method facilitates the delivery of large and/or charged therapeutics, which fail to effectively cross the blood-brain barrier (BBB). Thus, for a variety of growth factors, hormones, neuropeptides and therapeutics including insulin, oxytocin, orexin, and even stem cells, intranasal delivery is emerging as an efficient method of administration, and represents a promising therapeutic strategy for the treatment of diseases with CNS involvement, such as obesity, Alzheimer's disease, Parkinson's disease, Huntington's disease, depression, anxiety, autism spectrum disorders, seizures, drug addiction, eating disorders, and stroke. PMID: 23135822 [PubMed - indexed for MEDLINE]
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Related Articles Behavioural and EEG effects of chronic rapamycin treatment in a mouse model of tuberous sclerosis complex. Neuropharmacology. 2013 Apr;67:1-7 Authors: Cambiaghi M, Cursi M, Magri L, Castoldi V, Comi G, Minicucci F, Galli R, Leocani L Abstract Tuberous Sclerosis Complex (TSC) is a multisystem genetic disorder caused by mutation in either Tsc1 or Tsc2 genes that leads to the hyper activation of the mTOR pathway, a key signalling pathway for synaptic plasticity. TSC is characterized by benign tumors arising in different organs and severe neuropsychiatric symptoms, such as epilepsy, intellectual disability, autism, anxiety and depressive behaviour. Rapamycin is a potent inhibitor of mTOR and its efficacy in treating epilepsy and neurological symptoms remains elusive. In a mouse model in which Tsc1 has been deleted in embryonic telencephalic neural stem cells, we analyzed anxiety- and depression-like behaviour by elevated-plus maze (EPM), open-field test (OFT), forced-swim test (FST) and tail-suspension test (TST), after chronic administration of rapamycin. In addition, spectral analysis of background EEG was performed. Rapamycin-treated mutant mice displayed a reduction in anxiety- and depression-like phenotype, as shown by the EPM/OFT and FST, respectively. These results were inline with EEG power spectra outcomes. The same effects of rapamycin were observed in wild-type mice. Notably, in heterozygous animals we did not observe any EEG and/or behavioural variation after rapamycin treatment. Together these results suggest that both TSC1 deletion and chronic rapamycin treatment might have a role in modulating behaviour and brain activity, and point out to the potential usefulness of background EEG analysis in tracking brain dysfunction in parallel with behavioural testing. PMID: 23159330 [PubMed - indexed for MEDLINE]
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Related Articles Genomic and proteomic advances in autism research. Electrophoresis. 2012 Dec;33(24):3653-8 Authors: Maurer MH Abstract Recent studies suggest that adult neural stem cells (NSCs) may play a role in the pathogenesis of a number of the developmental disorders subsumed under the term autism spectrum disorders (ASD) that have in common impaired social interaction, communication deficits, and stereotypical behavior or interests. Since there is no "unifying hypothesis" about the etiology and pathogenesis of ASD, several factors have been associated with ASD, including genetic factors, physical co-morbidity, disturbances of brain structure and function, biochemical anomalies, cognitive impairment, and disorders of speech and emotional development, mostly the lack of empathy. Most of disturbances of brain interconnectivity are regarded as main problem in autism. Since NSCs have a distinct life cycle in the mammalian brain consisting of proliferation, migration, arborization, integration into existing neuronal circuits, and myelinization, disturbances in NSCs differentiation is thought to be deleterious. In the current review, I will summarize the results of genomic and proteomic studies finding susceptibility genes and proteins for autism with regard to NSCs differentiation and maturation. PMID: 23160986 [PubMed - indexed for MEDLINE]
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Related Articles Dense-map genome scan for dyslexia supports loci at 4q13, 16p12, 17q22; suggests novel locus at 7q36. Genes Brain Behav. 2013 Feb;12(1):56-69 Authors: Field LL, Shumansky K, Ryan J, Truong D, Swiergala E, Kaplan BJ Abstract Analysis of genetic linkage to dyslexia was performed using 133,165 array-based SNPs genotyped in 718 persons from 101 dyslexia-affected families. Results showed five linkage peaks with lod scores >2.3 (4q13.1, 7q36.1-q36.2, 7q36.3, 16p12.1, and 17q22). Of these five regions, three have been previously implicated in dyslexia (4q13.1, 16p12.1, and 17q22), three have been implicated in attention-deficit hyperactivity disorder (ADHD, which highly co-occurs with dyslexia; 4q13.1, 7q36.3, 16p12.1) and four have been implicated in autism (a condition characterized by language deficits; 7q36.1-q36.2, 7q36.3, 16p12.1, and 17q22). These results highlight the reproducibility of dyslexia linkage signals, even without formally significant lod scores, and suggest dyslexia predisposing genes with relatively major effects and locus heterogeneity. The largest lod score (2.80) occurred at 17q22 within the MSI2 gene, involved in neuronal stem cell lineage proliferation. Interestingly, the 4q13.1 linkage peak (lod 2.34) occurred immediately upstream of the LPHN3 gene, recently reported both linked and associated with ADHD. Separate analyses of larger pedigrees revealed lods >2.3 at 1-3 regions per family; one family showed strong linkage (lod 2.9) to a known dyslexia locus (18p11) not detected in our overall data, demonstrating the value of analyzing single large pedigrees. Association analysis identified no SNPs with genome-wide significance, although a borderline significant SNP (P = 6 × 10(-7)) occurred at 5q35.1 near FGF18, involved in laminar positioning of cortical neurons during development. We conclude that dyslexia genes with relatively major effects exist, are detectable by linkage analysis despite genetic heterogeneity, and show substantial overlapping predisposition with ADHD and autism. PMID: 23190410 [PubMed - indexed for MEDLINE]
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Related Articles Toxicity of the flame-retardant BDE-49 on brain mitochondria and neuronal progenitor striatal cells enhanced by a PTEN-deficient background. Toxicol Sci. 2013 Mar;132(1):196-210 Authors: Napoli E, Hung C, Wong S, Giulivi C Abstract Polybrominated diphenyl ethers (PBDEs) represent an important group of flame retardants extensively used, tonnage of which in the environment has been steadily increasing over the past 25 years. PBDEs or metabolites can induce neurotoxicity and mitochondrial dysfunction (MD) through a variety of mechanisms. Recently, PBDEs with < 5 Br substitutions (i.e., 2,2',4,4'-tetrabromodiphenyl ether [BDE-47] and 2,2',4,5'-tetrabromodiphenyl ether [BDE-49]) have gained interest because of their high bioaccumulation. In particular, congeners such as BDE-49 arise as one of the most biologically active, with concentrations typically lower than those observed for BDE-47 in biological tissues; however, its potential to cause MD at biologically relevant concentrations is unknown. To this end, the effect of BDE-49 was studied in brain mitochondria and neuronal progenitor striatal cells (NPC). BDE-49 uncoupled mitochondria at concentrations < 0.1 nM, whereas at > 1 nM, it inhibited the electron transport at Complex V (mixed type inhibition; IC(50) = 6 nM) and Complex IV (noncompetitive inhibition; IC(50) = 40 nM). These concentrations are easily achieved in plasma concentrations considering that BDE-49 (this study, 400-fold) and other PBDEs accumulate 1-3 orders of magnitude in the cells, particularly in mitochondria and microsomes. Similar effects were observed in NPC and exacerbated with PTEN (negative modulator of the PI3K/Akt pathway) deficiency, background associated with autism-like behavior, schizophrenia, and epilepsy. PBDE-mediated MD per se or enhanced by a background that confers susceptibility to this exposure may have profound implications in the energy balance of brain. PMID: 23288049 [PubMed - indexed for MEDLINE]
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Related Articles Modeling Timothy syndrome with iPS cells. J Cardiovasc Transl Res. 2013 Feb;6(1):1-9 Authors: Yazawa M, Dolmetsch RE Abstract Genetic mutations in ion channel genes that are associated with cardiac arrhythmias have been identified over the past several decades. However, little is known about the pathophysiological processes. An important limitation has been the difficulty of using human cardiomyocytes to study arrhythmias and identify drugs. To circumvent this issue, we have developed a method using human-induced pluripotent stem cells to generate cardiomyocytes from individuals with Timothy syndrome (TS), a genetic disorder characterized by QT prolongation, ventricular tachycardia, and autism. The TS ventricular-like cardiomyocytes exhibit deficits in contraction, electrical signaling, and calcium handling, as revealed by live cell imaging and electrophysiological studies. We tested candidate drugs in TS cardiomyocytes and found that roscovitine could successfully rescue these cellular phenotypes. The use of a human cellular model of cardiac arrhythmias provides a useful new platform not only to study disease mechanisms but also to develop new therapies to treat cardiac arrhythmias. PMID: 23299782 [PubMed - indexed for MEDLINE]
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Related Articles Timothy syndrome is associated with activity-dependent dendritic retraction in rodent and human neurons. Nat Neurosci. 2013 Feb;16(2):201-9 Authors: Krey JF, Paşca SP, Shcheglovitov A, Yazawa M, Schwemberger R, Rasmusson R, Dolmetsch RE Abstract L-type voltage gated calcium channels have an important role in neuronal development by promoting dendritic growth and arborization. A point mutation in the gene encoding Ca(V)1.2 causes Timothy syndrome, a neurodevelopmental disorder associated with autism spectrum disorders (ASDs). We report that channels with the Timothy syndrome alteration cause activity-dependent dendrite retraction in rat and mouse neurons and in induced pluripotent stem cell (iPSC)-derived neurons from individuals with Timothy syndrome. Dendrite retraction was independent of calcium permeation through the mutant channel, was associated with ectopic activation of RhoA and was inhibited by overexpression of the channel-associated GTPase Gem. These results suggest that Ca(V)1.2 can activate RhoA signaling independently of Ca(2+) and provide insights into the cellular basis of Timothy syndrome and other ASDs. PMID: 23313911 [PubMed - indexed for MEDLINE]
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Related Articles Conditional and domain-specific inactivation of the Tsc2 gene in neural progenitor cells. Genesis. 2013 Apr;51(4):284-92 Authors: Fu C, Ess KC Abstract Tuberous sclerosis complex (TSC) is a genetic disease characterized by multiorgan benign tumors as well as neurological manifestations. Epilepsy and autism are two of the more prevalent neurological complications and are usually severe. TSC is caused by mutations in either the TSC1 (encodes hamartin) or the TSC2 (encodes tuberin) genes with TSC2 mutations being associated with worse outcomes. Tuberin contains a highly conserved GTPase-activating protein (GAP) domain that indirectly inhibits mammalian target of rapamycin complex 1 (mTORC1). mTORC1 dysregulation is currently thought to cause much of the pathogenesis in TSC but mTORC1-independent mechanisms may also contribute. We generated a novel conditional allele of Tsc2 by flanking exons 36 and 37 with loxP sites. Mice homozygous for this knock-in Tsc2 allele are viable and fertile with normal appearing growth and development. Exposure to Cre recombinase then creates an in-frame deletion involving critical residues of the GAP domain. Homozygous conditional mutant mice generated using Emx1(Cre) have increased cortical mTORC1 signaling, severe developmental brain anomalies, seizures, and die within 3 weeks. We found that the normal levels of the mutant Tsc2 mRNA, though GAP-deficient tuberin protein, appear unstable and rapidly degraded. This novel animal model will allow further study of tuberin function including the requirement of the GAP domain for protein stability. PMID: 23359422 [PubMed - indexed for MEDLINE]
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Related Articles Meeting report: using stem cells for biological and therapeutics discovery in mental illness, April 2012. Stem Cells Transl Med. 2013 Mar;2(3):217-22 Authors: Panchision DM Abstract This report synthesizes the discussions during a workshop convened April 24-25, 2012, by the National Institute of Mental Health and the Foundation for the NIH in Bethesda, Maryland, that focused on progress and challenges in the use of patient-derived reprogrammed cells for basic biological discovery, target identification, screening, and drug development for mental illnesses such as schizophrenia, bipolar disorder, and autism spectrum disorders. The workshop revealed that the greatest progress has been made in reprogramming methods and agreed-upon standards for validating the resulting induced pluripotent stem cell lines. However, challenges remain in several areas, including efficiently generating and validating specific neural cell types with respect to regional identity, establishing assays with predictive validity to mental illness pathophysiology, and generating sufficient statistical power and data reproducibility across laboratories. A brainstorming session yielded a number of suggestions, including calls to (a) facilitate the replication of results by standardizing protocols and samples used across laboratories; (b) improve technology by generating cheaper/faster targeting methods, reporters, and assays; and (c) improve resource sharing and collaboration, with an emphasis on rapid sharing of new cell lines, technologies, and best practices, possibly incorporated into a public-private partnership. The meeting provided an important venue for academic, government, and private sector scientists to address potential opportunities for translational and clinical applications of reprogrammed cell research. A number of activities since the workshop have reflected the feedback from meeting participants. PMID: 23408104 [PubMed - indexed for MEDLINE]
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Related Articles A circuitry and biochemical basis for tuberous sclerosis symptoms: from epilepsy to neurocognitive deficits. Int J Dev Neurosci. 2013 Nov;31(7):667-78 Authors: Feliciano DM, Lin TV, Hartman NW, Bartley CM, Kubera C, Hsieh L, Lafourcade C, O'Keefe RA, Bordey A Abstract Tuberous sclerosis complex (TSC) is an autosomal dominant monogenetic disorder that is characterized by the formation of benign tumors in several organs as well as brain malformations and neuronal defects. TSC is caused by inactivating mutations in one of two genes, TSC1 and TSC2, resulting in increased activity of the mammalian Target of Rapamycin (mTOR). Here, we explore the cytoarchitectural and functional CNS aberrations that may account for the neurological presentations of TSC, notably seizures, hydrocephalus, and cognitive and psychological impairments. In particular, recent mouse models of brain lesions are presented with an emphasis on using electroporation to allow the generation of discrete lesions resulting from loss of heterozygosity during perinatal development. Cortical lesions are thought to contribute to epileptogenesis and worsening of cognitive defects. However, it has recently been suggested that being born with a mutant allele without loss of heterozygosity and associated cortical lesions is sufficient to generate cognitive and neuropsychiatric problems. We will thus discuss the function of mTOR hyperactivity on neuronal circuit formation and the potential consequences of being born heterozygous on neuronal function and the biochemistry of synaptic plasticity, the cellular substrate of learning and memory. Ultimately, a major goal of TSC research is to identify the cellular and molecular mechanisms downstream of mTOR underlying the neurological manifestations observed in TSC patients and identify novel therapeutic targets to prevent the formation of brain lesions and restore neuronal function. PMID: 23485365 [PubMed - in process]
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Related Articles Cortical interneurons from human pluripotent stem cells: prospects for neurological and psychiatric disease. Front Cell Neurosci. 2013;7:10 Authors: Arber C, Li M Abstract Cortical interneurons represent 20% of the cells in the cortex. These cells are local inhibitory neurons whose function is to modulate the firing activities of the excitatory projection neurons. Cortical interneuron dysfunction is believed to lead to runaway excitation underlying (or implicated in) seizure-based diseases, such as epilepsy, autism, and schizophrenia. The complex development of this cell type and the intricacies involved in defining the relative subtypes are being increasingly well defined. This has led to exciting experimental cell therapy in model organisms, whereby fetal-derived interneuron precursors can reverse seizure severity and reduce mortality in adult epileptic rodents. These proof-of-principle studies raise hope for potential interneuron-based transplantation therapies for treating epilepsy. On the other hand, cortical neurons generated from patient iPSCs serve as a valuable tool to explore genetic influences of interneuron development and function. This is a fundamental step in enhancing our understanding of the molecular basis of neuropsychiatric illnesses and the development of targeted treatments. Protocols are currently being developed for inducing cortical interneuron subtypes from mouse and human pluripotent stem cells. This review sets out to summarize the progress made in cortical interneuron development, fetal tissue transplantation and the recent advance in stem cell differentiation toward interneurons. PMID: 23493959 [PubMed]
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Related Articles Functional impacts of NRXN1 knockdown on neurodevelopment in stem cell models. PLoS One. 2013;8(3):e59685 Authors: Zeng L, Zhang P, Shi L, Yamamoto V, Lu W, Wang K Abstract Exonic deletions in NRXN1 have been associated with several neurodevelopmental disorders, including autism, schizophrenia and developmental delay. However, the molecular mechanism by which NRXN1 deletions impact neurodevelopment remains unclear. Here we used human induced pluripotent stem cells (hiPSCs) and human embryonic stem cells (hESCs) as models to investigate the functional impacts of NRXN1 knockdown. We first generated hiPSCs from skin fibroblasts and differentiated them into neural stem cells (NSCs). We reduced NRXN1 expression in NSCs via a controlled shRNAmir-based knockdown system during differentiation, and monitored the transcriptome alteration by RNA-Seq and quantitative PCR at several time points. Interestingly, half reduction of NRXN1 expression resulted in changes of expression levels for the cell adhesion pathway (20 genes, P = 2.8×10(-6)) and neuron differentiation pathway (13 genes, P = 2.1×10(-4)), implicating that single-gene perturbation can impact biological networks important for neurodevelopment. Furthermore, astrocyte marker GFAP was significantly reduced in a time dependent manner that correlated with NRXN1 reduction. This observation was reproduced in both hiPSCs and hESCs. In summary, based on in vitro models, NRXN1 deletions impact several biological processes during neurodevelopment, including synaptic adhesion and neuron differentiation. Our study highlights the utility of stem cell models in understanding the functional roles of copy number variations (CNVs) in conferring susceptibility to neurodevelopmental diseases. PMID: 23536886 [PubMed - indexed for MEDLINE]
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Related Articles Prenatal expression of MET receptor tyrosine kinase in the fetal mouse dorsal raphe nuclei and the visceral motor/sensory brainstem. Dev Neurosci. 2013;35(1):1-16 Authors: Wu HH, Levitt P Abstract Signaling via MET receptor tyrosine kinase (MET) has been implicated in a number of neurodevelopmental events, including cell migration, dendritic and axonal development and synaptogenesis. Related to its role in the development of forebrain circuitry, we recently identified a functional promoter variant of the MET gene that is associated with autism spectrum disorder (ASD). The association of the MET promoter variant rs1858830 C allele is significantly enriched in families with a child who has ASD and co-occurring gastrointestinal conditions. The expression of MET in the forebrain had been mapped in detail in the developing mouse and rhesus macaque. However, in mammals, its expression in the developing brainstem has not been studied extensively throughout developmental stages. Brainstem and autonomic circuitry are implicated in ASD pathophysiology and in gastrointestinal dysfunction. To advance our understanding of the neurodevelopmental influences of MET signaling in brainstem circuitry development, we employed in situ hybridization and immunohistochemistry to map the expression of Met and its ligand, Hgf, through prenatal development of the mouse midbrain and hindbrain. Our results reveal a highly selective expression pattern of Met in the brainstem, including a subpopulation of neurons in cranial motor nuclei (nVII, nA and nXII), B6 subgroup of the dorsal raphe, Barrington's nucleus, and a small subset of neurons in the nucleus of solitary tract. In contrast to Met, neither full-length nor known splice variants of Hgf were localized in the prenatal brainstem. RT-PCR revealed Hgf expression in target tissues of Met-expressing brainstem neurons, suggesting that MET in these neurons may be activated by HGF from peripheral sources. Together, these data suggest that MET signaling may influence the development of neurons that are involved in central regulation of gastrointestinal function, tongue movement, swallowing, speech, stress and mood. PMID: 23548689 [PubMed - indexed for MEDLINE]
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Related Articles Ataxin1L is a regulator of HSC function highlighting the utility of cross-tissue comparisons for gene discovery. PLoS Genet. 2013 Mar;9(3):e1003359 Authors: Kahle JJ, Souroullas GP, Yu P, Zohren F, Lee Y, Shaw CA, Zoghbi HY, Goodell MA Abstract Hematopoietic stem cells (HSCs) are rare quiescent cells that continuously replenish the cellular components of the peripheral blood. Observing that the ataxia-associated gene Ataxin-1-like (Atxn1L) was highly expressed in HSCs, we examined its role in HSC function through in vitro and in vivo assays. Mice lacking Atxn1L had greater numbers of HSCs that regenerated the blood more quickly than their wild-type counterparts. Molecular analyses indicated Atxn1L null HSCs had gene expression changes that regulate a program consistent with their higher level of proliferation, suggesting that Atxn1L is a novel regulator of HSC quiescence. To determine if additional brain-associated genes were candidates for hematologic regulation, we examined genes encoding proteins from autism- and ataxia-associated protein-protein interaction networks for their representation in hematopoietic cell populations. The interactomes were found to be highly enriched for proteins encoded by genes specifically expressed in HSCs relative to their differentiated progeny. Our data suggest a heretofore unappreciated similarity between regulatory modules in the brain and HSCs, offering a new strategy for novel gene discovery in both systems. PMID: 23555280 [PubMed - indexed for MEDLINE]
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Related Articles Directed differentiation and functional maturation of cortical interneurons from human embryonic stem cells. Cell Stem Cell. 2013 May 2;12(5):559-72 Authors: Maroof AM, Keros S, Tyson JA, Ying SW, Ganat YM, Merkle FT, Liu B, Goulburn A, Stanley EG, Elefanty AG, Widmer HR, Eggan K, Goldstein PA, Anderson SA, Studer L Abstract Human pluripotent stem cells are a powerful tool for modeling brain development and disease. The human cortex is composed of two major neuronal populations: projection neurons and local interneurons. Cortical interneurons comprise a diverse class of cell types expressing the neurotransmitter GABA. Dysfunction of cortical interneurons has been implicated in neuropsychiatric diseases, including schizophrenia, autism, and epilepsy. Here, we demonstrate the highly efficient derivation of human cortical interneurons in an NKX2.1::GFP human embryonic stem cell reporter line. Manipulating the timing of SHH activation yields three distinct GFP+ populations with specific transcriptional profiles, neurotransmitter phenotypes, and migratory behaviors. Further differentiation in a murine cortical environment yields parvalbumin- and somatostatin-expressing neurons that exhibit synaptic inputs and electrophysiological properties of cortical interneurons. Our study defines the signals sufficient for modeling human ventral forebrain development in vitro and lays the foundation for studying cortical interneuron involvement in human disease pathology. PMID: 23642365 [PubMed - indexed for MEDLINE]
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Related Articles Bioengineered stem cells in neural development and neurodegeneration research. Ageing Res Rev. 2013 Jun;12(3):739-48 Authors: Yuan SH, Shaner M Abstract The recent discovery of a simple method for making induced pluripotent stem cells (iPSC) from human somatic cells was a major scientific advancement that opened the way for many promising new developments in the study of developmental and degenerative diseases. iPSC have already been used to model many different types of neurological diseases, including autism, schizophrenia, Alzheimer's disease and Parkinson's disease. Because of their pluripotent property, iPSC offer the possibility of modeling human development in vitro. Their differentiation seems to follow the developmental timeline and obeys environmental cues. Clinically relevant phenotypes of neurodegenerative pathologies have also been observed using iPSC derived human neuronal cultures. Options for treatment are still some way off. Although some early research in mouse models has been encouraging, major obstacles remain for neural stem cell (NSC) transplantation therapy. However, iPSC now offer the prospect of an unlimited amount of human neurons or astrocytes for drug testing. The aim of this review is to summarize the recent progress in modeling neural development and neurological diseases using iPSC and to describe their applications for aging research and personalized medicine. PMID: 23651546 [PubMed - indexed for MEDLINE]
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Related Articles Enhanced derivation of mouse ESC-derived cortical interneurons by expression of Nkx2.1. Stem Cell Res. 2013 Jul;11(1):647-56 Authors: Petros TJ, Maurer CW, Anderson SA Abstract Forebrain GABAergic interneurons are divided into subgroups based on their neurochemical markers, connectivity and physiological properties. Abnormal interneuron function is implicated in the pathobiology of neurological disorders such as schizophrenia, autism, and epilepsy. Studies on interneuron development and their role in disease would benefit from an efficient mechanism for the production and selection of specific interneuron subgroups. In this study, we engineered a mouse embryonic stem cell (mESC) line for doxycycline-inducible expression of Nkx2.1, a required transcription factor for cortical interneurons derived from the medial ganglionic eminence (MGE). This mESC line was modified to express GFP in Lhx6(+) cells, a marker of newly postmitotic and mature MGE-derived cortical interneurons. The addition of doxycycline to differentiating ESCs efficiently induced Nkx2.1 protein and increased the production of GFP(+) cells. Transplantation of GFP(+) putative interneuron precursors resulted in migratory, morphological, and neurochemical features consistent with cortical interneuron fates. To test the hypothesis that Sonic hedgehog (Shh) primarily influences cortical interneuron fate determination through the induction of Nkx2.1, ESCs were grown with doxycycline and the Shh antagonist cyclopamine. We found induced Nkx2.1 renders Shh signaling dispensable for the generation of MGE-derived interneurons. These results demonstrate that inducible expression of fate determining genes in embryonic stem cells can be used to study fate determination of the developing forebrain. PMID: 23672829 [PubMed - in process]
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Related Articles The functional genetic link of NLGN4X knockdown and neurodevelopment in neural stem cells. Hum Mol Genet. 2013 Sep 15;22(18):3749-60 Authors: Shi L, Chang X, Zhang P, Coba MP, Lu W, Wang K Abstract Genetic mutations in NLGN4X (neuroligin 4), including point mutations and copy number variants (CNVs), have been associated with susceptibility to autism spectrum disorders (ASDs). However, it is unclear how mutations in NLGN4X result in neurodevelopmental defects. Here, we used neural stem cells (NSCs) as in vitro models to explore the impacts of NLGN4X knockdown on neurodevelopment. Using two shRNAmir-based vectors targeting NLGN4X and one control shRNAmir vector, we modulated NLGN4X expression and differentiated these NSCs into mature neurons. We monitored the neurodevelopmental process at Weeks 0, 0.5, 1, 2, 4 and 6, based on morphological analysis and whole-genome gene expression profiling. At the cellular level, in NSCs with NLGN4X knockdown, we observed increasingly delayed neuronal development and compromised neurite formation, starting from Week 2 through Week 6 post differentiation. At the molecular level, we identified multiple pathways, such as neurogenesis, neuron differentiation and muscle development, which are increasingly disturbed in cells with NLGN4X knockdown. Notably, several postsynaptic genes, including DLG4, NLGN1 and NLGN3, also have decreased expression. Based on in vitro models, NLGN4X knockdown directly impacts neurodevelopmental process during the formation of neurons and their connections. Our functional genomics study highlights the utility of NSCs models in understanding the functional roles of CNVs in affecting neurodevelopment and conferring susceptibility to neurodevelopmental diseases. PMID: 23710042 [PubMed - indexed for MEDLINE]
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Related Articles Timing of mTOR activation affects tuberous sclerosis complex neuropathology in mouse models. Dis Model Mech. 2013 Sep;6(5):1185-97 Authors: Magri L, Cominelli M, Cambiaghi M, Cursi M, Leocani L, Minicucci F, Poliani PL, Galli R Abstract Tuberous sclerosis complex (TSC) is a dominantly inherited disease with high penetrance and morbidity, and is caused by mutations in either of two genes, TSC1 or TSC2. Most affected individuals display severe neurological manifestations - such as intractable epilepsy, mental retardation and autism - that are intimately associated with peculiar CNS lesions known as cortical tubers (CTs). The existence of a significant genotype-phenotype correlation in individuals bearing mutations in either TSC1 or TSC2 is highly controversial. Similar to observations in humans, mouse modeling has suggested that a more severe phenotype is associated with mutation in Tsc2 rather than in Tsc1. However, in these mutant mice, deletion of either gene was achieved in differentiated astrocytes. Here, we report that loss of Tsc1 expression in undifferentiated radial glia cells (RGCs) early during development yields the same phenotype detected upon deletion of Tsc2 in the same cells. Indeed, the same aberrations in cortical cytoarchitecture, hippocampal disturbances and spontaneous epilepsy that have been detected in RGC-targeted Tsc2 mutants were observed in RGC-targeted Tsc1 mutant mice. Remarkably, thorough characterization of RGC-targeted Tsc1 mutants also highlighted subventricular zone (SVZ) disturbances as well as STAT3-dependent and -independent developmental-stage-specific defects in the differentiation potential of ex-vivo-derived embryonic and postnatal neural stem cells (NSCs). As such, deletion of either Tsc1 or Tsc2 induces mostly overlapping phenotypic neuropathological features when performed early during neurogenesis, thus suggesting that the timing of mTOR activation is a key event in proper neural development. PMID: 23744272 [PubMed - in process]
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Related Articles Therapeutic translation of iPSCs for treating neurological disease. Cell Stem Cell. 2013 Jun 6;12(6):678-88 Authors: Yu DX, Marchetto MC, Gage FH Abstract Somatic cellular reprogramming is a fast-paced and evolving field that is changing the way scientists approach neurological diseases. For the first time in the history of neuroscience, it is feasible to study the behavior of live neurons from patients with neurodegenerative diseases, such as Alzheimer's and Parkinson's disease, and neuropsychiatric diseases, such as autism and schizophrenia. In this Perspective, we will discuss reprogramming technology in the context of its potential use for modeling and treating neurological and psychiatric diseases and will highlight areas of caution and opportunities for improvement. PMID: 23746977 [PubMed - in process]
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Related Articles MeCP2 regulates the synaptic expression of a Dysbindin-BLOC-1 network component in mouse brain and human induced pluripotent stem cell-derived neurons. PLoS One. 2013;8(6):e65069 Authors: Larimore J, Ryder PV, Kim KY, Ambrose LA, Chapleau C, Calfa G, Gross C, Bassell GJ, Pozzo-Miller L, Smith Y, Talbot K, Park IH, Faundez V Abstract Clinical, epidemiological, and genetic evidence suggest overlapping pathogenic mechanisms between autism spectrum disorder (ASD) and schizophrenia. We tested this hypothesis by asking if mutations in the ASD gene MECP2 which cause Rett syndrome affect the expression of genes encoding the schizophrenia risk factor dysbindin, a subunit of the biogenesis of lysosome-related organelles complex-1 (BLOC-1), and associated interacting proteins. We measured mRNA and protein levels of key components of a dysbindin interaction network by, quantitative real time PCR and quantitative immunohistochemistry in hippocampal samples of wild-type and Mecp2 mutant mice. In addition, we confirmed results by performing immunohistochemistry of normal human hippocampus and quantitative qRT-PCR of human inducible pluripotent stem cells (iPSCs)-derived human neurons from Rett syndrome patients. We defined the distribution of the BLOC-1 subunit pallidin in human and mouse hippocampus and contrasted this distribution with that of symptomatic Mecp2 mutant mice. Neurons from mutant mice and Rett syndrome patients displayed selectively reduced levels of pallidin transcript. Pallidin immunoreactivity decreased in the hippocampus of symptomatic Mecp2 mutant mice, a feature most prominent at asymmetric synapses as determined by immunoelectron microcopy. Pallidin immunoreactivity decreased concomitantly with reduced BDNF content in the hippocampus of Mecp2 mice. Similarly, BDNF content was reduced in the hippocampus of BLOC-1 deficient mice suggesting that genetic defects in BLOC-1 are upstream of the BDNF phenotype in Mecp2 deficient mice. Our results demonstrate that the ASD-related gene Mecp2 regulates the expression of components belonging to the dysbindin interactome and these molecular differences may contribute to synaptic phenotypes that characterize Mecp2 deficiencies and ASD. PMID: 23750231 [PubMed - in process]
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Related Articles Therapeutic role of hematopoietic stem cells in autism spectrum disorder-related inflammation. Front Immunol. 2013;4:140 Authors: Siniscalco D, Bradstreet JJ, Antonucci N Abstract Autism and autism spectrum disorders (ASDs) are heterogeneous, severe neuro-developmental disorders with core symptoms of dysfunctions in social interactions and communication skills, restricted interests, repetitive - stereotypic verbal and non-verbal behaviors. Biomolecular evidence points to complex gene-environmental interactions in ASDs. Several biochemical processes are associated with ASDs: oxidative stress (including endoplasmic reticulum stress), decreased methylation capacity, limited production of glutathione; mitochondrial dysfunction, intestinal dysbiosis, increased toxic metal burden, and various immune abnormalities. The known immunological disorders include: T-lymphocyte populations and function, gene expression changes in monocytes, several autoimmune-related findings, high levels of N-acetylgalactosaminidase (which precludes macrophage activation), and primary immune deficiencies. These immunological observations may result in minicolumn structural changes in the brain, as well as, abnormal immune mediation of synaptic functions. Equally, these immune dysregulations serve as the rationale for immune-directed interventions such as hematopoietic stem cells (HSCs), which are pivotal in controlling chronic inflammation and in the restoration of immunological balance. These properties make them intriguing potential agents for ASD treatments. This prospective review will focus on the current state-of-the-art knowledge and challenges intrinsic in the application of HSCs for ASD-related immunological disorders. PMID: 23772227 [PubMed]
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Related Articles Stem cells as a good tool to investigate dysregulated biological systems in autism spectrum disorders. Autism Res. 2013 Oct;6(5):354-61 Authors: Griesi-Oliveira K, Sunaga DY, Alvizi L, Vadasz E, Passos-Bueno MR Abstract Identification of the causes of autism spectrum disorders (ASDs) is hampered by their genetic heterogeneity; however, the different genetic alterations leading to ASD seem to be implicated in the disturbance of common molecular pathways or biological processes. In this scenario, the search for differentially expressed genes (DEGs) between ASD patients and controls is a good alternative to identify the molecular etiology of such disorders. Here, we employed genome-wide expression analysis to compare the transcriptome of stem cells of human exfoliated deciduous teeth (SHEDs) of idiopathic autistic patients (n = 7) and control samples (n = 6). Nearly half of the 683 identified DEGs are expressed in the brain (P = 0.003), and a significant number of them are involved in mechanisms previously associated with ASD such as protein synthesis, cytoskeleton regulation, cellular adhesion and alternative splicing, which validate the use of SHEDs to disentangle the causes of autism. Autistic patients also presented overexpression of genes regulated by androgen receptor (AR), and AR itself, which in turn interacts with CHD8 (chromodomain helicase DNA binding protein 8), a gene recently shown to be associated with the cause of autism and found to be upregulated in some patients tested here. These data provide a rationale for the mechanisms through which CHD8 leads to these diseases. In summary, our results suggest that ASD share deregulated pathways and revealed that SHEDs represent an alternative cell source to be used in the understanding of the biological mechanisms involved in the etiology of ASD. PMID: 23801657 [PubMed - in process]
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Related Articles A role of CPEB1 in the modulation of proliferation and neuronal maturation of rat primary neural progenitor cells. Neurochem Res. 2013 Sep;38(9):1960-72 Authors: Kim KC, Kim JW, Choi CS, Han SY, Cheong JH, Han SH, Yang SI, Bahn GH, Shin CY Abstract Cytoplasmic polyadenylation binding protein 1 (CPEB1) is a RNA binding protein, which regulates translation of target mRNAs by regulating polyadenylation status. CPEB1 plays important roles in the regulation of germline cell development by modulating cell cycle progression through the polyadenylation of target mRNAs such as cyclin B1. Similar mechanism is reported in proliferating astrocytes by us, although CPEB1 is involved in the transport of target mRNAs as well as local translation at dendritic spines. In this study, we found the expression of CPEB1 in cultured rat primary neural progenitor cells (NPCs). EGF stimulation of cultured NPCs induced rapid phosphorylation of CPEB1, a hallmark of CPEB1-dependent translational control along with cyclin B1 polyadenylation and translation. EGF-induced activation of ERK1/2 and Aurora A kinase was responsible for CPEB1 phosphorylation. Pharmacological inhibition studies suggested that ERK1/2 is involved in the activation of Aurora A kinase and regulation of CPEB1 phosphorylation in cultured NPCs. Long-term incubation in EGF resulted in the down-regulation of CPEB1 expression, which further increased expression of cyclin B1 and cell cycle progression. When we down-regulated the expression of CPEB1 in NPCs by siRNA transfection, the proliferation of NPCs was increased. Increased NPCs proliferation by down-regulation of CPEB1 resulted in eventual up-regulation of neuronal differentiation with increase in both pre- and post-synaptic proteins. The results from the present study may suggest the importance of translational control in the regulation of neuronal development, an emerging concept in many neurodevelopmental and psychiatric disorders such as autism spectrum disorder. PMID: 23824559 [PubMed - indexed for MEDLINE]
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Related Articles Functional genomic screen of human stem cell differentiation reveals pathways involved in neurodevelopment and neurodegeneration. Proc Natl Acad Sci U S A. 2013 Jul 23;110(30):12361-6 Authors: Zhang Y, Schulz VP, Reed BD, Wang Z, Pan X, Mariani J, Euskirchen G, Snyder MP, Vaccarino FM, Ivanova N, Weissman SM, Szekely AM Abstract Human embryonic stem cells (hESCs) can be induced and differentiated to form a relatively homogeneous population of neuronal precursors in vitro. We have used this system to screen for genes necessary for neural lineage development by using a pooled human short hairpin RNA (shRNA) library screen and massively parallel sequencing. We confirmed known genes and identified several unpredicted genes with interrelated functions that were specifically required for the formation or survival of neuronal progenitor cells without interfering with the self-renewal capacity of undifferentiated hESCs. Among these are several genes that have been implicated in various neurodevelopmental disorders (i.e., brain malformations, mental retardation, and autism). Unexpectedly, a set of genes mutated in late-onset neurodegenerative disorders and with roles in the formation of RNA granules were also found to interfere with neuronal progenitor cell formation, suggesting their functional relevance in early neurogenesis. This study advances the feasibility and utility of using pooled shRNA libraries in combination with next-generation sequencing for a high-throughput, unbiased functional genomic screen. Our approach can also be used with patient-specific human-induced pluripotent stem cell-derived neural models to obtain unparalleled insights into developmental and degenerative processes in neurological or neuropsychiatric disorders with monogenic or complex inheritance. PMID: 23836664 [PubMed - indexed for MEDLINE]
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Related Articles The utility of patient specific induced pluripotent stem cells for the modelling of Autistic Spectrum Disorders. Psychopharmacology (Berl). 2014 Mar;231(6):1079-88 Authors: Cocks G, Curran S, Gami P, Uwanogho D, Jeffries AR, Kathuria A, Lucchesi W, Wood V, Dixon R, Ogilvie C, Steckler T, Price J Abstract Until now, models of psychiatric diseases have typically been animal models. Whether they were to be used to further understand the pathophysiology of the disorder, or as drug discovery tools, animal models have been the choice of preference in mimicking psychiatric disorders in an experimental setting. While there have been cellular models, they have generally been lacking in validity. This situation is changing with the advent of patient-specific induced pluripotent stem cells (iPSCs). In this article, we give a methodological evaluation of the current state of the iPS technology with reference to our own work in generating patient-specific iPSCs for the study of autistic spectrum disorder (ASD). In addition, we will give a broader perspective on the validity of this technology and to what extent it can be expected to complement animal models of ASD in the coming years. PMID: 23839283 [PubMed - in process]
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Related Articles GFAP expression and social deficits in transgenic mice overexpressing human sAPPα. Glia. 2013 Sep;61(9):1556-69 Authors: Bailey AR, Hou H, Song M, Obregon DF, Portis S, Barger S, Shytle D, Stock S, Mori T, Sanberg PG, Murphy T, Tan J Abstract Autistic individuals display impaired social interactions and language, and restricted, stereotyped behaviors. Elevated levels of secreted amyloid precursor protein-alpha (sAPPα), the product of α-secretase cleavage of APP, are found in the plasma of some individuals with autism. The sAPPα protein is neurotrophic and neuroprotective and recently showed a correlation to glial differentiation in human neural stem cells (NSCs) via the IL-6 pathway. Considering evidence of gliosis in postmortem autistic brains, we hypothesized that subsets of patients with autism would exhibit elevations in CNS sAPPα and mice generated to mimic this observation would display markers suggestive of gliosis and autism-like behavior. Elevations in sAPPα levels were observed in brains of autistic patients compared to controls. Transgenic mice engineered to overexpress human sAPPα (TgsAPPα mice) displayed hypoactivity, impaired sociability, increased brain glial fibrillary acidic protein (GFAP) expression, and altered Notch1 and IL-6 levels. NSCs isolated from TgsAPPα mice, and those derived from wild-type mice treated with sAPPα, displayed suppressed β-tubulin III and elevated GFAP expression. These results suggest that elevations in brain sAPPα levels are observed in subsets of individuals with autism and TgsAPPα mice display signs suggestive of gliosis and behavioral impairment. PMID: 23840007 [PubMed - indexed for MEDLINE]
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Related Articles Focal malformations of cortical development: new vistas for molecular pathogenesis. Neuroscience. 2013 Nov 12;252:262-76 Authors: Lim KC, Crino PB Abstract Focal malformations of cortical development (FMCD) are highly associated with several neurological disorders including intractable epilepsy and neurocognitive disabilities. Over the past decade, several FMCD subtypes have been linked to hyperactivation of the mammalian target of rapamycin (mTOR) signaling cascade. In view of the roles that mTOR plays in cell proliferation, size, motility, and stem cell phenotype, many of the features of FMCD such as cytomegaly, disorganized lamination, and expression of stem cell markers can be explained by enhanced mTOR signaling. FMCD result from several distinct and fascinating molecular mechanisms including biallelic gene inactivation, somatic mutation, and potentially, viral infection. These mechanisms have been directly linked to mTOR activation. Perhaps most compelling, pharmacological inhibition of mTOR has been implemented successfully in clinical trials for select FMCD and provides a new vista for treatment. PMID: 23892008 [PubMed - in process]
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Related Articles Differentiation from human pluripotent stem cells of cortical neurons of the superficial layers amenable to psychiatric disease modeling and high-throughput drug screening. Transl Psychiatry. 2013;3:e294 Authors: Boissart C, Poulet A, Georges P, Darville H, Julita E, Delorme R, Bourgeron T, Peschanski M, Benchoua A Abstract Cortical neurons of the superficial layers (II-IV) represent a pivotal neuronal population involved in the higher cognitive functions of the human and are particularly affected by psychiatric diseases with developmental manifestations such as schizophrenia and autism. Differentiation protocols of human pluripotent stem cells (PSC) into cortical neurons have been achieved, opening the way to in vitro modeling of neuropsychiatric diseases. However, these protocols commonly result in the asynchronous production of neurons typical for the different layers of the cortex within an extended period of culture, thus precluding the analysis of specific subtypes of neurons in a standardized manner. Addressing this issue, we have successfully captured a stable population of self-renewing late cortical progenitors (LCPs) that synchronously and massively differentiate into glutamatergic cortical neurons of the upper layers. The short time course of differentiation into neurons of these progenitors has made them amenable to high-throughput assays. This has allowed us to analyze the capability of LCPs at differentiating into post mitotic neurons as well as extending and branching neurites in response to a collection of selected bioactive molecules. LCPs and cortical neurons of the upper layers were successfully produced from patient-derived-induced PSC, indicating that this system enables functional studies of individual-specific cortical neurons ex vivo for disease modeling and therapeutic purposes. PMID: 23962924 [PubMed - in process]
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Related Articles Transplantation of human cord blood mononuclear cells and umbilical cord-derived mesenchymal stem cells in autism. J Transl Med. 2013;11:196 Authors: Lv YT, Zhang Y, Liu M, Qiuwaxi JN, Ashwood P, Cho SC, Huan Y, Ge RC, Chen XW, Wang ZJ, Kim BJ, Hu X Abstract BACKGROUND: Autism is a pervasive neurodevelopmental disorder. At present there are no defined mechanisms of pathogenesis and therapy is mostly limited to behavioral interventions. Stem cell transplantation may offer a unique treatment strategy for autism due to immune and neural dysregulation observed in this disease. This non-randomized, open-label, single center phase I/II trial investigated the safety and efficacy of combined transplantation of human cord blood mononuclear cells (CBMNCs) and umbilical cord-derived mesenchymal stem cells (UCMSCs) in treating children with autism. METHODS: 37 subjects diagnosed with autism were enrolled into this study and divided into three groups: CBMNC group (14 subjects, received CBMNC transplantation and rehabilitation therapy), Combination group (9 subjects, received both CBMNC and UCMSC transplantation and rehabilitation therapy), and Control group (14 subjects, received only rehabilitation therapy). Transplantations included four stem cell infusions through intravenous and intrathecal injections once a week. Treatment safety was evaluated with laboratory examinations and clinical assessment of adverse effects. The Childhood Autism Rating Scale (CARS), Clinical Global Impression (CGI) scale and Aberrant Behavior Checklist (ABC) were adopted to assess the therapeutic efficacy at baseline (pre-treatment) and following treatment. RESULTS: There were no significant safety issues related to the treatment and no observed severe adverse effects. Statistically significant differences were shown on CARS, ABC scores and CGI evaluation in the two treatment groups compared to the control at 24 weeks post-treatment (p < 0.05). CONCLUSIONS: Transplantation of CBMNCs demonstrated efficacy compared to the control group; however, the combination of CBMNCs and UCMSCs showed larger therapeutic effects than the CBMNC transplantation alone. There were no safety issues noted during infusion and the whole monitoring period. TRIAL REGISTRATION: ClinicalTrials.gov: NCT01343511, Title "Safety and Efficacy of Stem Cell Therapy in Patients with Autism". PMID: 23978163 [PubMed - in process]
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Related Articles Congenital hypoplasia of the cerebellum: developmental causes and behavioral consequences. Front Neuroanat. 2013;7:29 Authors: Basson MA, Wingate RJ Abstract Over the last 60 years, the spotlight of research has periodically returned to the cerebellum as new techniques and insights have emerged. Because of its simple homogeneous structure, limited diversity of cell types and characteristic behavioral pathologies, the cerebellum is a natural home for studies of cell specification, patterning, and neuronal migration. However, recent evidence has extended the traditional range of perceived cerebellar function to include modulation of cognitive processes and implicated cerebellar hypoplasia and Purkinje neuron hypo-cellularity with autistic spectrum disorder. In the light of this emerging frontier, we review the key stages and genetic mechanisms behind cerebellum development. In particular, we discuss the role of the midbrain hindbrain isthmic organizer in the development of the cerebellar vermis and the specification and differentiation of Purkinje cells and granule neurons. These developmental processes are then considered in relation to recent insights into selected human developmental cerebellar defects: Joubert syndrome, Dandy-Walker malformation, and pontocerebellar hypoplasia. Finally, we review current research that opens up the possibility of using the mouse as a genetic model to study the role of the cerebellum in cognitive function. PMID: 24027500 [PubMed - as supplied by publisher]
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Related Articles Neurons generated by direct conversion of fibroblasts reproduce synaptic phenotype caused by autism-associated neuroligin-3 mutation. Proc Natl Acad Sci U S A. 2013 Oct 8;110(41):16622-7 Authors: Chanda S, Marro S, Wernig M, Südhof TC Abstract Recent studies suggest that induced neuronal (iN) cells that are directly transdifferentiated from nonneuronal cells provide a powerful opportunity to examine neuropsychiatric diseases. However, the validity of using this approach to examine disease-specific changes has not been demonstrated. Here, we analyze the phenotypes of iN cells that were derived from murine embryonic fibroblasts cultured from littermate wild-type and mutant mice carrying the autism-associated R704C substitution in neuroligin-3. We show that neuroligin-3 R704C-mutant iN cells exhibit a large and selective decrease in AMPA-type glutamate receptor-mediated synaptic transmission without changes in NMDA-type glutamate receptor- or in GABAA receptor-mediated synaptic transmission. Thus, the synaptic phenotype observed in R704C-mutant iN cells replicates the previously observed phenotype of R704C-mutant neurons. Our data show that the effect of the R704C mutation is applicable even to neurons transdifferentiated from fibroblasts and constitute a proof-of-concept demonstration that iN cells can be used for cellular disease modeling. PMID: 24046374 [PubMed - indexed for MEDLINE]
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Related Articles Autologous bone marrow mononuclear cell therapy for autism: an open label proof of concept study. Stem Cells Int. 2013;2013:623875 Authors: Sharma A, Gokulchandran N, Sane H, Nagrajan A, Paranjape A, Kulkarni P, Shetty A, Mishra P, Kali M, Biju H, Badhe P Abstract Cellular therapy is an emerging therapeutic modality with a great potential for the treatment of autism. Recent findings show that the major underlying pathogenetic mechanisms of autism are hypoperfusion and immune alterations in the brain. So conceptually, cellular therapy which facilitates counteractive processes of improving perfusion by angiogenesis and balancing inflammation by immune regulation would exhibit beneficial clinical effects in patients with autism. This is an open label proof of concept study of autologous bone marrow mononuclear cells (BMMNCs) intrathecal transplantation in 32 patients with autism followed by multidisciplinary therapies. All patients were followed up for 26 months (mean 12.7). Outcome measures used were ISAA, CGI, and FIM/Wee-FIM scales. Positron Emission Tomography-Computed Tomography (PET-CT) scan recorded objective changes. Out of 32 patients, a total of 29 (91%) patients improved on total ISAA scores and 20 patients (62%) showed decreased severity on CGI-I. The difference between pre- and postscores was statistically significant (P < 0.001) on Wilcoxon matched-pairs signed rank test. On CGI-II 96% of patients showed global improvement. The efficacy was measured on CGI-III efficacy index. Few adverse events including seizures in three patients were controlled with medications. The encouraging results of this leading clinical study provide future directions for application of cellular therapy in autism. PMID: 24062774 [PubMed]
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Related Articles Drug discovery for autism spectrum disorder: challenges and opportunities. Nat Rev Drug Discov. 2013 Oct;12(10):777-90 Authors: Ghosh A, Michalon A, Lindemann L, Fontoura P, Santarelli L Abstract The rising rates of autism spectrum disorder (ASD) and the lack of effective medications to treat its core symptoms have led to an increased sense of urgency to identify therapies for this group of neurodevelopmental conditions. Developing drugs for ASD, however, has been challenging because of a limited understanding of its pathophysiology, difficulties in modelling the disease in vitro and in vivo, the heterogeneity of symptoms, and the dearth of prior experience in clinical development. In the past few years these challenges have been mitigated by considerable advances in our understanding of forms of ASD caused by single-gene alterations, such as fragile X syndrome and tuberous sclerosis. In these cases we have gained insights into the pathophysiological mechanisms underlying these conditions. In addition, they have aided in the development of animal models and compounds with the potential for disease modification in clinical development. Moreover, genetic studies are illuminating the molecular pathophysiology of ASD, and new tools such as induced pluripotent stem cells offer novel possibilities for drug screening and disease diagnostics. Finally, large-scale collaborations between academia and industry are starting to address some of the key barriers to developing drugs for ASD. Here, we propose a conceptual framework for drug discovery in ASD encompassing target identification, drug profiling and considerations for clinical trials in this novel area. PMID: 24080699 [PubMed - indexed for MEDLINE]
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Related Articles Transcriptome comparison of human neurons generated using induced pluripotent stem cells derived from dental pulp and skin fibroblasts. PLoS One. 2013;8(10):e75682 Authors: Chen J, Lin M, Foxe JJ, Pedrosa E, Hrabovsky A, Carroll R, Zheng D, Lachman HM Abstract Induced pluripotent stem cell (iPSC) technology is providing an opportunity to study neuropsychiatric disorders through the capacity to grow patient-specific neurons in vitro. Skin fibroblasts obtained by biopsy have been the most reliable source of cells for reprogramming. However, using other somatic cells obtained by less invasive means would be ideal, especially in children with autism spectrum disorders (ASD) and other neurodevelopmental conditions. In addition to fibroblasts, iPSCs have been developed from cord blood, lymphocytes, hair keratinocytes, and dental pulp from deciduous teeth. Of these, dental pulp would be a good source for neurodevelopmental disorders in children because obtaining material is non-invasive. We investigated its suitability for disease modeling by carrying out gene expression profiling, using RNA-seq, on differentiated neurons derived from iPSCs made from dental pulp extracted from deciduous teeth (T-iPSCs) and fibroblasts (F-iPSCs). This is the first RNA-seq analysis comparing gene expression profiles in neurons derived from iPSCs made from different somatic cells. For the most part, gene expression profiles were quite similar with only 329 genes showing differential expression at a nominally significant p-value (p<0.05), of which 63 remained significant after correcting for genome-wide analysis (FDR <0.05). The most striking difference was the lower level of expression detected for numerous members of the all four HOX gene families in neurons derived from T-iPSCs. In addition, an increased level of expression was seen for several transcription factors expressed in the developing forebrain (FOXP2, OTX1, and LHX2, for example). Overall, pathway analysis revealed that differentially expressed genes that showed higher levels of expression in neurons derived from T-iPSCs were enriched for genes implicated in schizophrenia (SZ). The findings suggest that neurons derived from T-iPSCs are suitable for disease-modeling neuropsychiatric disorder and may have some advantages over those derived from F-iPSCs. PMID: 24098394 [PubMed - in process]
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Related Articles Effects of maternal immune activation on adult neurogenesis in the subventricular zone-olfactory bulb pathway and olfactory discrimination. Schizophr Res. 2013 Dec;151(1-3):1-11 Authors: Liu YH, Lai WS, Tsay HJ, Wang TW, Yu JY Abstract Maternal infection and maternal immune activation (MIA) during pregnancy increase risks for psychiatric disorders such as schizophrenia and autism. Many deficits related to psychiatric disorders are observed in adult offspring of MIA animal models, including behavioral abnormalities, morphological defects in various brain regions, and dysregulation of neurotransmitter systems. It has previously been shown that MIA impairs adult neurogenesis in the dentate gyrus of the hippocampus. In this study, we examined whether MIA affects adult neurogenesis in the subventricular zone (SVZ)-olfactory bulb (OB) pathway. Polyinosinic-polycytidylic acid (PolyI:C), a synthetic analog of double-stranded RNA mimicking viral infection, was injected into pregnant mice on gestation day 9.5 to activate immune systems. In the SVZ-OB pathway of adult offspring, different cell types of the neural stem cell lineage responded differently to MIA. Neural stem cells and neuroblasts were decreased. Cell proliferation of transit-amplifying cells was impaired. Consequently, newborn neurons were reduced in the OB. Olfactory deficiency has been suggested as a biomarker for schizophrenia. Here we found that olfactory discrimination was compromised in adult MIA offspring. Taken together, these findings show that MIA leads to defective adult neurogenesis in the SVZ-OB pathway, and the impairment of adult neurogenesis may lead to deficits in olfactory functions. PMID: 24113206 [PubMed - in process]
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Related Articles SHANK3 and IGF1 restore synaptic deficits in neurons from 22q13 deletion syndrome patients. Nature. 2013 Nov 14;503(7475):267-71 Authors: Shcheglovitov A, Shcheglovitova O, Yazawa M, Portmann T, Shu R, Sebastiano V, Krawisz A, Froehlich W, Bernstein JA, Hallmayer JF, Dolmetsch RE Abstract Phelan-McDermid syndrome (PMDS) is a complex neurodevelopmental disorder characterized by global developmental delay, severely impaired speech, intellectual disability, and an increased risk of autism spectrum disorders (ASDs). PMDS is caused by heterozygous deletions of chromosome 22q13.3. Among the genes in the deleted region is SHANK3, which encodes a protein in the postsynaptic density (PSD). Rare mutations in SHANK3 have been associated with idiopathic ASDs, non-syndromic intellectual disability, and schizophrenia. Although SHANK3 is considered to be the most likely candidate gene for the neurological abnormalities in PMDS patients, the cellular and molecular phenotypes associated with this syndrome in human neurons are unknown. We generated induced pluripotent stem (iPS) cells from individuals with PMDS and autism and used them to produce functional neurons. We show that PMDS neurons have reduced SHANK3 expression and major defects in excitatory, but not inhibitory, synaptic transmission. Excitatory synaptic transmission in PMDS neurons can be corrected by restoring SHANK3 expression or by treating neurons with insulin-like growth factor 1 (IGF1). IGF1 treatment promotes formation of mature excitatory synapses that lack SHANK3 but contain PSD95 and N-methyl-D-aspartate (NMDA) receptors with fast deactivation kinetics. Our findings provide direct evidence for a disruption in the ratio of cellular excitation and inhibition in PMDS neurons, and point to a molecular pathway that can be recruited to restore it. PMID: 24132240 [PubMed - indexed for MEDLINE]
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Related Articles Role of the PTEN signaling pathway in autism spectrum disorder. Neurosci Bull. 2013 Dec;29(6):773-8 Authors: Lv JW, Cheng TL, Qiu ZL, Zhou WH Abstract Autism is an etiologically heterogeneous group of neurodevelopmental disorders, diagnosed mostly by the clinical behavioral phenotypes. The concept that the tumor-related gene PTEN plays a critical role in autism spectrum disorder has emerged over the last decade. In this review, we focus on the essential role of the PTEN signaling pathway in neuronal differentiation and the formation of neural circuitry, as well as genetic mouse models with Pten manipulations. Particularly, accumulated data suggest that the effect of PTEN on neural stem-cell development contributes significantly to the pathophysiology of autism spectrum disorders. PMID: 24136242 [PubMed - in process]
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Related Articles Help for the child with autism. Sci Am. 2013 Oct;309(4):72-7 Authors: Lange N, McDougle C PMID: 24137859 [PubMed - indexed for MEDLINE]
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Related Articles Stereotypical alterations in cortical patterning are associated with maternal illness-induced placental dysfunction. J Neurosci. 2013 Oct 23;33(43):16874-88 Authors: Carpentier PA, Haditsch U, Braun AE, Cantu AV, Moon HM, Price RO, Anderson MP, Saravanapandian V, Ismail K, Rivera M, Weimann JM, Palmer TD Abstract We have previously shown in mice that cytokine-mediated damage to the placenta can temporarily limit the flow of nutrients and oxygen to the fetus. The placental vulnerability is pronounced before embryonic day 11, when even mild immune challenge results in fetal loss. As gestation progresses, the placenta becomes increasingly resilient to maternal inflammation, but there is a narrow window in gestation when the placenta is still vulnerable to immune challenge yet resistant enough to allow for fetal survival. This gestational window correlates with early cortical neurogenesis in the fetal brain. Here, we show that maternal illness during this period selectively alters the abundance and laminar positioning of neuronal subtypes influenced by the Tbr1, Satb2, and Ctip2/Fezf2 patterning axis. The disturbances also lead to a laminar imbalance in the proportions of projection neurons and interneurons in the adult and are sufficient to cause changes in social behavior and cognition. These data illustrate how the timing of an illness-related placental vulnerability causes developmental alterations in neuroanatomical systems and behaviors that are relevant to autism spectrum disorders. PMID: 24155294 [PubMed - indexed for MEDLINE]
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Related Articles Effect of the environmental pollutant hexachlorobenzene (HCB) on the neuronal differentiation of mouse embryonic stem cells. Int J Environ Res Public Health. 2013 Oct;10(10):5244-56 Authors: Addae C, Cheng H, Martinez-Ceballos E Abstract Exposure to persistent environmental pollutants may constitute an important factor on the onset of a number of neurological disorders such as autism, Parkinson's disease, and Attention Deficit Disorder (ADD), which have also been linked to reduced GABAergic neuronal function. GABAergic neurons produce γ-aminobutyric acid (GABA), which is the main inhibitory neurotransmitter in the brain. However, the lack of appropriate models has hindered the study of suspected environmental pollutants on GABAergic function. In this work, we have examined the effect of hexachlorobenzene (HCB), a persistent and bioaccumulative environmental pollutant, on the function and morphology of GABAergic neurons generated in vitro from mouse embryonic stem (ES) cells. We observed that: (1) treatment with 0.5 nM HCB did not affect cell viability, but affected the neuronal differentiation of ES cells; (2) HCB induced the production of reactive oxygen species (ROS); and (3) HCB repressed neurite outgrowth in GABAergic neurons, but this effect was reversed by the ROS scavenger N-acetylcysteine (NAC). Our study also revealed that HCB did not significantly interfere with the function of K+ ion channels in the neuronal soma, which indicates that this pollutant does not affect the maturation of the GABAergic neuronal soma. Our results suggest a mechanism by which environmental pollutants interfere with normal GABAergic neuronal function and may promote the onset of a number of neurological disorders such as autism and ADD. PMID: 24157519 [PubMed - in process]
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Related Articles Straight talk with... Ricardo Dolmetsch. Interview by Elie Dolgin. Nat Med. 2013 Nov;19(11):1360 Authors: Dolmetsch R Abstract Neuroscience, in recent years, has started to look like a graveyard for drug development, with many large pharmaceutical companies either eliminating their brain disorder programs or cutting back heavily on such research. Novartis seemed to have made exactly this kind of drastic change two years ago when the company announced plans to shutter its neuroscience operations at its global headquarters in Basel, Switzerland. But the company made it known then that its intention was to ultimately set up a new neuroscience division at the company's US base in Cambridge, Massachusetts. The US site was initially picked to take advantage of the local academic strength in the field of psychiatric genetics. Now, it seems that Novartis is also looking to add stem cell technologies to the mix with the appointment in August of Ricardo Dolmetsch as the company's global head of neurosciences-the first new hire for the company's reincarnated division. As a professor at California's Stanford University School of Medicine for the past ten years, Dolmetsch made his name using induced pluripotent stem (iPS) cells to study a rare form of autism known as Timothy syndrome. Elie Dolgin met with Dolmetsch at the Novartis Institutes for BioMedical Research in the Technology Square area of Cambridge to discuss how he plans to succeed where so many others have failed. PMID: 24202377 [PubMed - indexed for MEDLINE]
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Related Articles Perspectives on the Use of Stem Cells for Autism Treatment. Stem Cells Int. 2013;2013:262438 Authors: Siniscalco D, Bradstreet JJ, Sych N, Antonucci N Abstract Autism and autism spectrum disorders (ASDs) are complex neurodevelopmental disorders. ASDs are clinically defined by deficits in communication, social skills, and repetitive and/or restrictive interests and behaviours. With the prevalence rates for ASDs rapidly increasing, the need for effective therapies for autism is a priority for biomedical research. Currently available medications do not target the core symptoms, can have markedly adverse side-effects, and are mainly palliative for negative behaviours. The development of molecular and regenerative interventions is progressing rapidly, and medicine holds great expectations for stem cell therapies. Cells could be designed to target the observed molecular mechanisms of ASDs, that is, abnormal neurotransmitter regulation, activated microglia, mitochondrial dysfunction, blood-brain barrier disruptions, and chronic intestinal inflammation. Presently, the paracrine, secretome, and immunomodulatory effects of stem cells would appear to be the likely mechanisms of application for ASD therapeutics. This review will focus on the potential use of the various types of stem cells: embryonic, induced pluripotential, fetal, and adult stem cells as targets for ASD therapeutics. PMID: 24222772 [PubMed - as supplied by publisher]
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Related Articles Human pluripotent stem cell models of autism spectrum disorder: emerging frontiers, opportunities, and challenges towards neuronal networks in a dish. Psychopharmacology (Berl). 2014 Mar;231(6):1089-104 Authors: Aigner S, Heckel T, Zhang JD, Andreae LC, Jagasia R Abstract Autism spectrum disorder (ASD) is characterized by deficits in language development and social cognition and the manifestation of repetitive and restrictive behaviors. Despite recent major advances, our understanding of the pathophysiological mechanisms leading to ASD is limited. Although most ASD cases have unknown genetic underpinnings, animal and human cellular models of several rare, genetically defined syndromic forms of ASD have provided evidence for shared pathophysiological mechanisms that may extend to idiopathic cases. Here, we review our current knowledge of the genetic basis and molecular etiology of ASD and highlight how human pluripotent stem cell-based disease models have the potential to advance our understanding of molecular dysfunction. We summarize landmark studies in which neuronal cell populations generated from human embryonic stem cells and patient-derived induced pluripotent stem cells have served to model disease mechanisms, and we discuss recent technological advances that may ultimately allow in vitro modeling of specific human neuronal circuitry dysfunction in ASD. We propose that these advances now offer an unprecedented opportunity to help better understand ASD pathophysiology. This should ultimately enable the development of cellular models for ASD, allowing drug screening and the identification of molecular biomarkers for patient stratification. PMID: 24232378 [PubMed - in process]
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Related Articles Decitabine alters the expression of Mecp2 isoforms via dynamic DNA methylation at the Mecp2 regulatory elements in neural stem cells. Mol Autism. 2013;4(1):46 Authors: Liyanage VR, Zachariah RM, Rastegar M Abstract BACKGROUND: Aberrant MeCP2 expression in brain is associated with neurodevelopmental disorders including autism. In the brain of stressed mouse and autistic human patients, reduced MeCP2 expression is correlated with Mecp2/MECP2 promoter hypermethylation. Altered expression of MeCP2 isoforms (MeCP2E1 and MeCP2E2) is associated with neurological disorders, highlighting the importance of proper regulation of both isoforms. While known regulatory elements (REs) within the MECP2/Mecp2 promoter and intron 1 are involved in MECP2/Mecp2 regulation, Mecp2 isoform-specific regulatory mechanisms are unknown. We hypothesized that DNA methylation at these REs may impact the expression of Mecp2 isoforms. METHODS: We used a previously characterized in vitro differentiating neural stem cell (NSC) system to investigate the interplay between Mecp2 isoform-specific expression and DNA methylation at the Mecp2 REs. We studied altered expression of Mecp2 isoforms, affected by global DNA demethylation and remethylation, induced by exposure and withdrawal of decitabine (5-Aza-2'-deoxycytidine). Further, we performed correlation analysis between DNA methylation at the Mecp2 REs and the expression of Mecp2 isoforms after decitabine exposure and withdrawal. RESULTS: At different stages of NSC differentiation, Mecp2 isoforms showed reciprocal expression patterns associated with minor, but significant changes in DNA methylation at the Mecp2 REs. Decitabine treatment induced Mecp2e1/MeCP2E1 (but not Mecp2e2) expression at day (D) 2, associated with DNA demethylation at the Mecp2 REs. In contrast, decitabine withdrawal downregulated both Mecp2 isoforms to different extents at D8, without affecting DNA methylation at the Mecp2 REs. NSC cell fate commitment was minimally affected by decitabine under tested conditions. Expression of both isoforms negatively correlated with methylation at specific regions of the Mecp2 promoter, both at D2 and D8. The correlation between intron 1 methylation and Mecp2e1 (but not Mecp2e2) varied depending on the stage of NSC differentiation (D2: negative; D8: positive). CONCLUSIONS: Our results show the correlation between the expression of Mecp2 isoforms and DNA methylation in differentiating NSC, providing insights on the potential role of DNA methylation at the Mecp2 REs in Mecp2 isoform-specific expression. The ability of decitabine to induce Mecp2e1/MeCP2E1, but not Mecp2e2 suggests differential sensitivity of Mecp2 isoforms to decitabine and is important for future drug therapies for autism. PMID: 24238559 [PubMed]
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Related Articles Modeling human neurological disorders with induced pluripotent stem cells. J Neurochem. 2013 Nov 29; Authors: Imaizumi Y, Okano H Abstract Human induced pluripotent stem (iPS) cells obtained by reprogramming technology are a source of great hope, not only in terms of applications in regenerative medicine, such as cell transplantation therapy, but also for modeling human diseases and new drug development. In particular, the production of iPS cells from the somatic cells of patients with intractable diseases and their subsequent differentiation into cells at affected sites (e.g., neurons, cardiomyocytes, hepatocytes, and myocytes) has permitted the in vitro construction of disease models that contain patient-specific genetic information. For example, disease-specific iPS cells have been established from patients with neuropsychiatric disorders, including schizophrenia and autism, as well as from those with neurodegenerative diseases, including Parkinson's disease and Alzheimer's disease. A multi-omics analysis of neural cells originating from patient-derived iPS cells may thus enable investigators to elucidate the pathogenic mechanisms of neurological diseases that have heretofore been unknown. In addition, large-scale screening of chemical libraries with disease-specific iPS cells is currently underway and is expected to lead to new drug discovery. Accordingly, this review outlines the progress made via the use of patient-derived iPS cells toward the modeling of neurological disorders, the testing of existing drugs, and the discovery of new drugs. The production of human induced pluripotent stem (iPS) cells from the patients' somatic cells and their subsequent differentiation into specific cells have permitted the in vitro construction of disease models that contain patient-specific genetic information. Furthermore, innovations of gene-editing technologies on iPS cells are enabling new approaches for illuminating the pathogenic mechanisms of human diseases. In this review article, we outlined the current status of neurological diseases-specific iPS cell research and described recently obtained knowledge in the form of actual examples. PMID: 24286589 [PubMed - as supplied by publisher]
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Related Articles Mice with deficient BK channel function show impaired prepulse inhibition and spatial learning, but normal working and spatial reference memory. PLoS One. 2013;8(11):e81270 Authors: Typlt M, Mirkowski M, Azzopardi E, Ruettiger L, Ruth P, Schmid S Abstract Genetic variations in the large-conductance, voltage- and calcium activated potassium channels (BK channels) have been recently implicated in mental retardation, autism and schizophrenia which all come along with severe cognitive impairments. In the present study we investigate the effects of functional BK channel deletion on cognition using a genetic mouse model with a knock-out of the gene for the pore forming α-subunit of the channel. We tested the F1 generation of a hybrid SV129/C57BL6 mouse line in which the slo1 gene was deleted in both parent strains. We first evaluated hearing and motor function to establish the suitability of this model for cognitive testing. Auditory brain stem responses to click stimuli showed no threshold differences between knockout mice and their wild-type littermates. Despite of muscular tremor, reduced grip force, and impaired gait, knockout mice exhibited normal locomotion. These findings allowed for testing of sensorimotor gating using the acoustic startle reflex, as well as of working memory, spatial learning and memory in the Y-maze and the Morris water maze, respectively. Prepulse inhibition on the first day of testing was normal, but the knockout mice did not improve over the days of testing as their wild-type littermates did. Spontaneous alternation in the y-maze was normal as well, suggesting that the BK channel knock-out does not impair working memory. In the Morris water maze knock-out mice showed significantly slower acquisition of the task, but normal memory once the task was learned. Thus, we propose a crucial role of the BK channels in learning, but not in memory storage or recollection. PMID: 24303038 [PubMed - in process]
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Related Articles iPSC-derived neurons as a higher-throughput readout for autism: promises and pitfalls. Trends Mol Med. 2014 Feb;20(2):91-104 Authors: Prilutsky D, Palmer NP, Smedemark-Margulies N, Schlaeger TM, Margulies DM, Kohane IS Abstract The elucidation of disease etiologies and establishment of robust, scalable, high-throughput screening assays for autism spectrum disorders (ASDs) have been impeded by both inaccessibility of disease-relevant neuronal tissue and the genetic heterogeneity of the disorder. Neuronal cells derived from induced pluripotent stem cells (iPSCs) from autism patients may circumvent these obstacles and serve as relevant cell models. To date, derived cells are characterized and screened by assessing their neuronal phenotypes. These characterizations are often etiology-specific or lack reproducibility and stability. In this review, we present an overview of efforts to study iPSC-derived neurons as a model for autism, and we explore the plausibility of gene expression profiling as a reproducible and stable disease marker. PMID: 24374161 [PubMed - in process]
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Related Articles Random or stochastic monoallelic expressed genes are enriched for neurodevelopmental disorder candidate genes. PLoS One. 2013;8(12):e85093 Authors: Jeffries AR, Collier DA, Vassos E, Curran S, Ogilvie CM, Price J Abstract Random or stochastic monoallelic expressed genes (StMA genes) represent a unique form of monoallelic expression where allelic choice is made at random early in development. The consequential clonal diversity provides opportunity for functional heterozygosity in tissues such as the brain, and can impact on both development and disease. We investigate the relationship of StMA expressed genes previously identified in clonal neural stem cells with the neurodevelopmental disorders autism and schizophrenia. We found that StMA genes show an overrepresentation of schizophrenia risk candidates identified by genome wide association studies from the genetic association database. Similar suggestive enrichment was also found for genes from the NHGRI genome-wide association study catalog and a psychiatric genetics consortium schizophrenia dataset although these latter more robust gene lists did not achieve statistical significance. We also examined multiple sources of copy number variation (CNV) datasets from autism and schizophrenia cohorts. After taking into account total gene numbers and CNV size, both autism and schizophrenia associated CNVs appeared to show an enrichment of StMA genes relative to the control CNV datasets. Since the StMA genes were originally identified in neural stem cells, bias due to the neural transcriptome is possible. To address this, we randomly sampled neural stem cell expressed genes and repeated the tests. After a significant number of iterations, neural stem cell expressed genes did not show an overrepresentation in autism or schizophrenia CNV datasets. Therefore, irrespective of the neural derived transcriptome, StMA genes originally identified in neural stem cells show an overrepresentation in CNVs associated with autism and schizophrenia. If this association is functional, then the regulation (or dysregulation) of this form of allelic expression status within tissues such as the brain may be a contributory risk factor for neurodevelopmental disorders and may also influence disease discordance sometimes observed in monozygotic twins. PMID: 24386451 [PubMed - in process]
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Related Articles Glutamate-Mediated Signaling and Autism Spectrum Disorders: Emerging Treatment Targets. Curr Pharm Des. 2014 Jan 10; Authors: Yang P, Chang CL Abstract Autism spectrum disorders (ASD) are developmental disorders which are characterized by deficits in reciprocal social interactions and communication, as well as the presence of impairing repetitive behaviors and restricted interests. Prior work examining human pathology, model systems and genetic studies have led to the current conceptualization of ASD as disorder of synaptic formation and functioning (a "synapsopathy"). In this regard, glutamate, the major excitatory neurotransmitter in central nervous system synaptic transmission with roles in learning, memory and synaptic plasticity, is hypothesized to play an important role in the pathophysiology of ASD. Molecules targeting glutamate signaling have been suggested to possess therapeutic potential for ASD treatment. This review focuses on the role of glutamate receptors structure and function, describes synaptic cell-adhesion molecule pathways related to glutamate and/or ASD, introduces a rare disease approach in the novel drug development of ASD treatment, and report glutamate-related clinical trials. We will also present the promising techniques of human-induced pluripotent stem cells, which may afford researchers the ability to study the relationships between clinical phenotype, cellular responses and glutamate involvement in ASD. PMID: 24410563 [PubMed - as supplied by publisher]
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Related Articles Pharmacological characterisation of ligand- and voltage-gated ion channels expressed in human iPSC-derived forebrain neurons. Psychopharmacology (Berl). 2014 Mar;231(6):1105-24 Authors: Dage JL, Colvin EM, Fouillet A, Langron E, Roell WC, Li J, Mathur SX, Mogg AJ, Schmitt MG, Felder CC, Merchant KM, Isaac J, Broad LM, Sher E, Ursu D Abstract INTRODUCTION: Genetic causes, or predisposition, are increasingly accepted to be part of the ethiopathogenesis of many neuropsychiatric diseases. While genes can be studied in any type of cells, their physiological function in human brain cells is difficult to evaluate, particularly in living subjects. METHODS: As a first step towards the characterisation of human inducible pluripotent stem cell (iPSC)-derived neurons from autism spectrum disorder (ASD) patients, we used gene expression and functional studies to define the regional identity of the typical forebrain differentiation, demonstrate expression patterns of genes of interest in ASD and understand the properties of 'control' iPSC-derived neurons (iCell-Neurons™), with a focus on receptors and ion channels that play a central role in synaptic physio-pathology. RESULTS AND DISCUSSION: The gene expression profile of the iCell-Neurons™ closely resembled that observed in neonatal prefrontal cortex tissues. Functional studies, performed mainly using calcium flux assays, demonstrated the presence of ionotropic glutamate (α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid and N-methyl-D-aspartate) and gamma-aminobutyric acid type A receptors. Voltage-gated sodium and calcium channels were also identified using similar techniques. CONCLUSIONS: Overall, the results reported here suggest that iCell-Neurons™ are a good cellular model of a relatively immature forebrain human neuron population that can be used both as a control in comparison to patients cells, and as host cells in which mutations, insertions and deletions can be used in order to study the molecular mechanisms of ASD and other neurological disorders in an isogenic cellular background. PMID: 24429870 [PubMed - in process]
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Related Articles Great expectations: autism spectrum disorder and induced pluripotent stem cell technologies. Stem Cell Rev. 2014 Apr;10(2):145-50 Authors: Liu EY, Scott CT Abstract New applications of iPSC technology to research on complex idiopathic conditions raise several important ethical and social considerations for potential research participants and their families. In this short review, we examine these issues through the lens of emerging research on autism spectrum disorder (ASD). We begin by describing the current state of iPSC technology in research on ASD. Then we discuss how the social history of and current controversies in autism research combined with the emergence of autism-specific iPSC biobanks indicate an urgent need for researchers to clearly communicate the limitations and possibilities of iPSC research to ensure research participants have the ability to provide fully informed, voluntary consent. We conclude by offering recommendations to bolster informed consent for research involving iPSC biobanks, both in the specific context of ASD and more broadly. PMID: 24488263 [PubMed - in process]
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Related Articles A human pluripotent stem cell platform for assessing developmental neural toxicity screening. Stem Cell Res Ther. 2013;4 Suppl 1:S12 Authors: Hou Z, Zhang J, Schwartz MP, Stewart R, Page CD, Murphy WL, Thomson JA Abstract A lack of affordable and effective testing and screening procedures mean surprisingly little is known about the health hazards of many of the tens of thousands of chemicals in use in the world today. The recent rise in the number of children affected by neurological disorders such as autism has stirred valuable debate about the role chemicals play in our daily life, highlighting the need for improved methods of assessing chemicals for developmental neural toxicity. PMID: 24565336 [PubMed - in process]
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Related Articles Brain region-specific expression of MeCP2 isoforms correlates with DNA methylation within Mecp2 regulatory elements. PLoS One. 2014;9(3):e90645 Authors: Olson CO, Zachariah RM, Ezeonwuka CD, Liyanage VR, Rastegar M Abstract MeCP2 is a critical epigenetic regulator in brain and its abnormal expression or compromised function leads to a spectrum of neurological disorders including Rett Syndrome and autism. Altered expression of the two MeCP2 isoforms, MeCP2E1 and MeCP2E2 has been implicated in neurological complications. However, expression, regulation and functions of the two isoforms are largely uncharacterized. Previously, we showed the role of MeCP2E1 in neuronal maturation and reported MeCP2E1 as the major protein isoform in the adult mouse brain, embryonic neurons and astrocytes. Recently, we showed that DNA methylation at the regulatory elements (REs) within the Mecp2 promoter and intron 1 impact the expression of Mecp2 isoforms in differentiating neural stem cells. This current study is aimed for a comparative analysis of temporal, regional and cell type-specific expression of MeCP2 isoforms in the developing and adult mouse brain. MeCP2E2 displayed a later expression onset than MeCP2E1 during mouse brain development. In the adult female and male brain hippocampus, both MeCP2 isoforms were detected in neurons, astrocytes and oligodendrocytes. Furthermore, MeCP2E1 expression was relatively uniform in different brain regions (olfactory bulb, striatum, cortex, hippocampus, thalamus, brainstem and cerebellum), whereas MeCP2E2 showed differential enrichment in these brain regions. Both MeCP2 isoforms showed relatively similar distribution in these brain regions, except for cerebellum. Lastly, a preferential correlation was observed between DNA methylation at specific CpG dinucleotides within the REs and Mecp2 isoform-specific expression in these brain regions. Taken together, we show that MeCP2 isoforms display differential expression patterns during brain development and in adult mouse brain regions. DNA methylation patterns at the Mecp2 REs may impact this differential expression of Mecp2/MeCP2 isoforms in brain regions. Our results significantly contribute towards characterizing the expression profiles of Mecp2/MeCP2 isoforms and thereby provide insights on the potential role of MeCP2 isoforms in the developing and adult brain. PMID: 24594659 [PubMed - in process]
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Related Articles Functional differentiation of stem cell-derived neurons from different murine backgrounds. Front Cell Neurosci. 2014;8:49 Authors: Barth L, Sütterlin R, Nenniger M, Vogt KE Abstract Murine stem cell-derived neurons have been used to study a wide variety of neuropsychiatric diseases with a hereditary component, ranging from autism to Alzheimer's. While a significant amount of data on their molecular biology has been generated, there is little data on the physiology of these cultures. Different mouse strains show clear differences in behavioral and other neurobiologically relevant readouts. We have studied the physiology of early differentiation and network formation in neuronal cultures derived from three different mouse embryonic stem cell lines. We have found largely overlapping patterns with some significant differences in the timing of the functional milestones. Neurons from R1 showed the fastest development of intrinsic excitability, while E14Tg2a and J1 were slower. This was also reflected in an earlier appearance of synaptic activity in R1 cultures, while E14Tg2a and J1 were delayed by up to 2 days. In conclusion, stem cells from all backgrounds could be successfully differentiated into functioning neural networks with similar developmental patterns. Differences in the timing of specific milestones, suggest that control cell lines and time-points should be carefully chosen when investigating genetic alterations that lead to subtle deficits in neuronal function. PMID: 24600351 [PubMed]
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Related Articles Fragile X proteins in stem cell maintenance and differentiation. Stem Cells. 2014 Mar 19; Authors: Li Y, Zhao X Abstract Fragile X syndrome (FXS), the most common genetic form of autism spectrum disorder, is caused by deficiency of the fragile X mental retardation protein (FMRP). Despite extensive research and scientific progress, understanding how FMRP regulates brain development and function remains a major challenge. FMRP is a neuronal RNA-binding protein that binds about a third of messenger RNAs in the brain and controls their translation, stability, and cellular localization. The absence of FMRP results in increased protein synthesis, leading to enhanced signaling in a number of intracellular pathways, including the mTOR, mGLuR5, ERK, Gsk3β, PI3K, and insulin pathways. Until recently, FXS was largely considered a deficit of mature neurons; however, a number of new studies have shown that FMRP may also play important roles in stem cells, among them neural stem cells, germ line stem cells, and pluripotent stem cells. In this review, we will cover these newly discovered functions of FMRP, as well as the other two fragile X-related proteins, in stem cells. We will also discuss the literature on the use of stem cells, particularly neural stem cells and induced pluripotent stem cells, as model systems for studying the functions of FMRP in neuronal development. Stem Cells 2014. PMID: 24648324 [PubMed - as supplied by publisher]
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Related Articles Efficient specification of interneurons from human pluripotent stem cells by dorsoventral and rostrocaudal modulation. Stem Cells. 2014 Mar 19; Authors: Kim TG, Yao R, Monnell T, Cho JH, Vasudevan A, Koh A, Kumar T P, Moon M, Datta D, Bolshakov VY, Kim KS, Chung S Abstract GABAergic interneurons regulate cortical neural networks by providing inhibitory inputs, and their malfunction, resulting in failure to intricately regulate neural circuit balance, is implicated in brain diseases such as Schizophrenia, Autism and Epilepsy. During early development, GABAergic interneuron progenitors arise from the ventral telencephalic area such as Medial Ganglionic Eminence (MGE) and caudal ganglionic eminence (CGE) by the actions of secreted signaling molecules from nearby organizers, and migrate to their target sites where they form local synaptic connections. In this study, using combinatorial and temporal modulation of developmentally relevant dorsoventral and rostrocaudal signaling pathways (SHH, Wnt and FGF8), we efficiently generated MGE cells from multiple human pluripotent stem cells. Especially, modulation of FGF8/FGF19 signaling efficiently modultated MGE vs CGE differentiation. Human MGE cells spontaneously differentiated into Lhx6-expressing GABAergic interneurons and showed migratory properties. These human MGE-derived neurons generated GABA, fired action potential and displayed robust GABAergic postsynaptic activity. Transplantation into rodent brains results in well-contained neural grafts enriched with GABAergic interneurons that migrate in the host and mature to express somatostatin or parvalbumin. Thus, we propose that signaling modulation recapitulating normal developmental patterns efficiently generates human GABAergic interneurons. This strategy represents a novel tool in regenerative medicine, developmental studies, disease modeling, bioassay, and drug screening. Stem Cells 2014. PMID: 24648391 [PubMed - as supplied by publisher]
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Related Articles Induced pluripotent stem cell derived forebrain neurons from FXS individuals show defects in initial neurite outgrowth. Stem Cells Dev. 2014 Mar 24; Authors: Doers ME, Musser MT, Nichol R, Baker MW, Berndt ER, Gomez TM, Zhang SC, Abbeduto L, Bhattacharyya A Abstract Fragile X syndrome (FXS) is the most common form of inherited intellectual disability and is closely linked with autism. The genetic basis of FXS is an expansion of CGG repeats in the 5'-untranslated region of the FMR1 gene on the X chromosome leading to the loss of expression of the Fragile X Mental Retardation Protein (FMRP). The cause of FXS has been known for over 20 years, yet the full molecular and cellular consequences of this mutation remain unclear. Although mouse and fly models have provided significant understanding of this disorder and its effects on the central nervous system, insight from human studies is limited. We have created human induced pluripotent stem cell lines (iPSCs) from fibroblasts obtained from individuals with FXS to enable in vitro modeling of the human disease. Three young boys with FXS who came from a well-characterized cohort representative of the range of affectedness typical for the syndrome were recruited to aid in linking cellular and behavioral phenotypes. The FMR1 mutation is preserved during the reprogramming of patient fibroblasts to iPSCs. Mosaicism of the CGG repeat length in one of the patient's fibroblasts allowed for the generation of isogenic lines with differing CGG repeat lengths from the same patient. FXS forebrain neurons were differentiated from these iPSCs and display defective neurite initiation and extension. These cells provide a well-characterized resource to examine potential neuronal deficits caused by FXS as well as the function of FMRP in human neurons. PMID: 24654675 [PubMed - as supplied by publisher]
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Related Articles Prostaglandin E2 alters Wnt-dependent migration and proliferation in neuroectodermal stem cells: implications for autism spectrum disorders. Cell Commun Signal. 2014;12(1):19 Authors: Wong CT, Ahmad E, Li H, Crawford DA Abstract Prostaglandin E2 (PGE2) is a natural lipid-derived molecule that is involved in important physiological functions. Abnormal PGE2 signalling has been associated with pathologies of the nervous system. Previous studies provide evidence for the interaction of PGE2 and canonical Wnt signalling pathways in non-neuronal cells. Since the Wnt pathway is crucial in the development and organization of the brain, the main goal of this study is to determine whether collaboration between these pathways exists in neuronal cell types. We report that PGE2 interacts with canonical Wnt signalling through PKA and PI-3K in neuroectodermal (NE-4C) stem cells. We used time-lapse microscopy to determine that PGE2 increases the final distance from origin, path length travelled, and the average speed of migration in Wnt-activated cells. Furthermore, PGE2 alters distinct cellular phenotypes that are characteristic of Wnt-induced NE-4C cells, which corresponds to the modified splitting behaviour of the cells. We also found that in Wnt-induced cells the level of β-catenin protein was increased and the expression levels of Wnt-target genes (Ctnnb1, Ptgs2, Ccnd1, Mmp9) was significantly upregulated in response to PGE2 treatment. This confirms that PGE2 activated the canonical Wnt signalling pathway. Furthermore, the upregulated genes have been previously associated with ASD. Our findings show, for the first time, evidence for cross-talk between PGE2 and Wnt signalling in neuronal cells, where PKA and PI-3K might act as mediators between the two pathways. Given the importance of PGE2 and Wnt signalling in prenatal development of the nervous system, our study provides insight into how interaction between these two pathways may influence neurodevelopment. PMID: 24656144 [PubMed - in process]
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Related Articles Reduced synaptic activity in neuronal networks derived from embryonic stem cells of murine Rett syndrome model. Front Cell Neurosci. 2014;8:79 Authors: Barth L, Sütterlin R, Nenniger M, Vogt KE Abstract Neurodevelopmental diseases such as the Rett syndrome (RTT) have received renewed attention, since the mechanisms involved may underlie a broad range of neuropsychiatric disorders such as schizophrenia and autism. In vertebrates early stages in the functional development of neurons and neuronal networks are difficult to study. Embryonic stem cell-derived neurons provide an easily accessible tool to investigate neuronal differentiation and early network formation. We used in vitro cultures of neurons derived from murine embryonic stem cells missing the methyl-CpG-binding protein 2 (MECP2) gene (MeCP2-/y) and from wild type cells of the corresponding background. Cultures were assessed using whole-cell patch-clamp electrophysiology and immunofluorescence. We studied the functional maturation of developing neurons and the activity of the synaptic connections they formed. Neurons exhibited minor differences in the developmental patterns for their intrinsic parameters, such as resting membrane potential and excitability; with the MeCP2-/y cells showing a slightly accelerated development, with shorter action potential half-widths at early stages. There was no difference in the early phase of synapse development, but as the cultures matured, significant deficits became apparent, particularly for inhibitory synaptic activity. MeCP2-/y embryonic stem cell-derived neuronal cultures show clear developmental deficits that match phenotypes observed in slice preparations and thus provide a compelling tool to further investigate the mechanisms behind RTT pathophysiology. PMID: 24723848 [PubMed]
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Related Articles The Roots of Autism and ADHD Twin Study in Sweden (RATSS). Twin Res Hum Genet. 2014 Apr 15;:1-13 Authors: Bölte S, Willfors C, Berggren S, Norberg J, Poltrago L, Mevel K, Coco C, Fransson P, Borg J, Sitnikov R, Toro R, Tammimies K, Anderlid BM, Nordgren A, Falk A, Meyer U, Kere J, Landén M, Dalman C, Ronald A, Anckarsäter H, Lichtenstein P Abstract Neurodevelopmental disorders affect a substantial minority of the general population. Their origins are still largely unknown, but a complex interplay of genetic and environmental factors causing disturbances of the central nervous system's maturation and a variety of higher cognitive skills is presumed. Only limited research of rather small sample size and narrow scope has been conducted in neurodevelopmental disorders using a twin-differences design. The Roots of Autism and ADHD Twin Study in Sweden (RATSS) is an ongoing project targeting monozygotic twins discordant for categorical or dimensional autistic and inattentive/hyperactive-impulsive phenotypes as well as other neurodevelopmental disorders, and typically developing twin controls. Included pairs are 9 years of age or older, and comprehensively assessed for psychopathology, medical history, neuropsychology, and dysmorphology, as well as structural, functional, and molecular brain imaging. Specimens are collected for induced pluripotent (iPS) and neuroepithelial stem cells, genetic, gut bacteria, protein-/monoamine, and electron microscopy analyses. RATSS's objective is to generate a launch pad for novel surveys to understand the complexity of genotype-environment-phenotype interactions in autism spectrum disorder and attention-deficit hyperactivity disorder (ADHD). By October 2013, RATSS had collected data from 55 twin pairs, among them 10 monozygotic pairs discordant for autism spectrum disorder, seven for ADHD, and four for other neurodevelopmental disorders. This article describes the design, recruitment, data collection, measures, collected pairs' characteristics, as well as ongoing and planned analyses in RATSS. Potential gains of the study comprise the identification of environmentally mediated biomarkers, the emergence of candidates for drug development, translational modeling, and new leads for prevention of incapacitating outcomes. PMID: 24735654 [PubMed - as supplied by publisher]
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Related Articles Heat shock alters the expression of schizophrenia and autism candidate genes in an induced pluripotent stem cell model of the human telencephalon. PLoS One. 2014;9(4):e94968 Authors: Lin M, Zhao D, Hrabovsky A, Pedrosa E, Zheng D, Lachman HM Abstract Schizophrenia (SZ) and autism spectrum disorders (ASD) are highly heritable neuropsychiatric disorders, although environmental factors, such as maternal immune activation (MIA), play a role as well. Cytokines mediate the effects of MIA on neurogenesis and behavior in animal models. However, MIA stimulators can also induce a febrile reaction, which could have independent effects on neurogenesis through heat shock (HS)-regulated cellular stress pathways. However, this has not been well-studied. To help understand the role of fever in MIA, we used a recently described model of human brain development in which induced pluripotent stem cells (iPSCs) differentiate into 3-dimensional neuronal aggregates that resemble a first trimester telencephalon. RNA-seq was carried out on aggregates that were heat shocked at 39°C for 24 hours, along with their control partners maintained at 37°C. 186 genes showed significant differences in expression following HS (p<0.05), including known HS-inducible genes, as expected, as well as those coding for NGFR and a number of SZ and ASD candidates, including SMARCA2, DPP10, ARNT2, AHI1 and ZNF804A. The degree to which the expression of these genes decrease or increase during HS is similar to that found in copy loss and copy gain copy number variants (CNVs), although the effects of HS are likely to be transient. The dramatic effect on the expression of some SZ and ASD genes places HS, and perhaps other cellular stressors, into a common conceptual framework with disease-causing genetic variants. The findings also suggest that some candidate genes that are assumed to have a relatively limited impact on SZ and ASD pathogenesis based on a small number of positive genetic findings, such as SMARCA2 and ARNT2, may in fact have a much more substantial role in these disorders - as targets of common environmental stressors. PMID: 24736721 [PubMed - in process]
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