51
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Zeng L, Zhang P, Shi L, Yamamoto V, Lu W, Wang K. Functional impacts of NRXN1 knockdown on neurodevelopment in stem cell models. PLoS One 2013; 8:e59685. [PMID: 23536886 PMCID: PMC3607566 DOI: 10.1371/journal.pone.0059685] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2012] [Accepted: 02/16/2013] [Indexed: 12/28/2022] Open
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.
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Affiliation(s)
- Liyun Zeng
- Zilhka Neurogenetic Institute, Keck School of Medicine, University of Southern California, Los Angeles, California, United States of America
| | - Peilin Zhang
- Eli and Edythe Broad Center for Regenerative Medicine and Stem Cell Research, Keck School of Medicine, University of Southern California, Los Angeles, California, United States of America
| | - Lingling Shi
- Zilhka Neurogenetic Institute, Keck School of Medicine, University of Southern California, Los Angeles, California, United States of America
| | - Vicky Yamamoto
- Eli and Edythe Broad Center for Regenerative Medicine and Stem Cell Research, Keck School of Medicine, University of Southern California, Los Angeles, California, United States of America
- Department of Biochemistry and Molecular Biology, Keck School of Medicine, University of Southern California, Los Angeles, California, United States of America
| | - Wange Lu
- Eli and Edythe Broad Center for Regenerative Medicine and Stem Cell Research, Keck School of Medicine, University of Southern California, Los Angeles, California, United States of America
- Department of Biochemistry and Molecular Biology, Keck School of Medicine, University of Southern California, Los Angeles, California, United States of America
- * E-mail: (WL); (KW)
| | - Kai Wang
- Zilhka Neurogenetic Institute, Keck School of Medicine, University of Southern California, Los Angeles, California, United States of America
- Department of Psychiatry and Department of Preventive Medicine, Keck School of Medicine, University of Southern California, Los Angeles, California, United States of America
- * E-mail: (WL); (KW)
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52
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Connecting signaling pathways underlying communication to ASD vulnerability. INTERNATIONAL REVIEW OF NEUROBIOLOGY 2013; 113:97-133. [PMID: 24290384 DOI: 10.1016/b978-0-12-418700-9.00004-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Language is a human-specific trait that likely facilitated the rapid increase in higher cognitive function in our species. A consequence of the selective pressures that have permitted language and cognition to flourish in humans is the unique vulnerability of humans to developing cognitive disorders such as autism. Therefore, progress in understanding the genetic and molecular mechanisms of language evolution should provide insight into such disorders. Here, we discuss the few genes that have been identified in both autism-related pathways and language. We also detail the use of animal models to uncover the function of these genes at a mechanistic and circuit level. Finally, we present the use of comparative genomics to identify novel genes and gene networks involved in autism. Together, all of these approaches will allow for a broader and deeper view of the molecular brain mechanisms involved in the evolution of language and the gene disruptions associated with autism.
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Kwan KY. Transcriptional dysregulation of neocortical circuit assembly in ASD. INTERNATIONAL REVIEW OF NEUROBIOLOGY 2013; 113:167-205. [PMID: 24290386 DOI: 10.1016/b978-0-12-418700-9.00006-x] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Autism spectrum disorders (ASDs) impair social cognition and communication, key higher-order functions centered in the human neocortex. The assembly of neocortical circuitry is a precisely regulated developmental process susceptible to genetic alterations that can ultimately affect cognitive abilities. Because ASD is an early onset neurodevelopmental disorder that disrupts functions executed by the neocortex, miswiring of neocortical circuits has been hypothesized to be an underlying mechanism of ASD. This possibility is supported by emerging genetic findings and data from imaging studies. Recent research on neocortical development has identified transcription factors as key determinants of neocortical circuit assembly, mediating diverse processes including neuronal specification, migration, and wiring. Many of these TFs (TBR1, SOX5, FEZF2, and SATB2) have been implicated in ASD. Here, I will discuss the functional roles of these transcriptional programs in neocortical circuit development and their neurobiological implications for the emerging etiology of ASD.
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Affiliation(s)
- Kenneth Y Kwan
- Department of Human Genetics, Molecular & Behavioral Neuroscience Institute (MBNI), University of Michigan, Ann Arbor, Michigan, USA.
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54
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Millan MJ. An epigenetic framework for neurodevelopmental disorders: from pathogenesis to potential therapy. Neuropharmacology 2012; 68:2-82. [PMID: 23246909 DOI: 10.1016/j.neuropharm.2012.11.015] [Citation(s) in RCA: 151] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2012] [Revised: 11/11/2012] [Accepted: 11/22/2012] [Indexed: 12/12/2022]
Abstract
Neurodevelopmental disorders (NDDs) are characterized by aberrant and delayed early-life development of the brain, leading to deficits in language, cognition, motor behaviour and other functional domains, often accompanied by somatic symptoms. Environmental factors like perinatal infection, malnutrition and trauma can increase the risk of the heterogeneous, multifactorial and polygenic disorders, autism and schizophrenia. Conversely, discrete genetic anomalies are involved in Down, Rett and Fragile X syndromes, tuberous sclerosis and neurofibromatosis, the less familiar Phelan-McDermid, Sotos, Kleefstra, Coffin-Lowry and "ATRX" syndromes, and the disorders of imprinting, Angelman and Prader-Willi syndromes. NDDs have been termed "synaptopathies" in reference to structural and functional disturbance of synaptic plasticity, several involve abnormal Ras-Kinase signalling ("rasopathies"), and many are characterized by disrupted cerebral connectivity and an imbalance between excitatory and inhibitory transmission. However, at a different level of integration, NDDs are accompanied by aberrant "epigenetic" regulation of processes critical for normal and orderly development of the brain. Epigenetics refers to potentially-heritable (by mitosis and/or meiosis) mechanisms controlling gene expression without changes in DNA sequence. In certain NDDs, prototypical epigenetic processes of DNA methylation and covalent histone marking are impacted. Conversely, others involve anomalies in chromatin-modelling, mRNA splicing/editing, mRNA translation, ribosome biogenesis and/or the regulatory actions of small nucleolar RNAs and micro-RNAs. Since epigenetic mechanisms are modifiable, this raises the hope of novel therapy, though questions remain concerning efficacy and safety. The above issues are critically surveyed in this review, which advocates a broad-based epigenetic framework for understanding and ultimately treating a diverse assemblage of NDDs ("epigenopathies") lying at the interface of genetic, developmental and environmental processes. This article is part of the Special Issue entitled 'Neurodevelopmental Disorders'.
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Affiliation(s)
- Mark J Millan
- Unit for Research and Discovery in Neuroscience, IDR Servier, 125 chemin de ronde, 78290 Croissy sur Seine, Paris, France.
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55
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Maurer MH. Genomic and proteomic advances in autism research. Electrophoresis 2012; 33:3653-8. [PMID: 23160986 DOI: 10.1002/elps.201200382] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2012] [Revised: 07/31/2012] [Accepted: 08/06/2012] [Indexed: 01/10/2023]
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.
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Affiliation(s)
- Martin H Maurer
- Department of Physiology and Pathophysiology, University of Heidelberg, Heidelberg, Germany.
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56
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Lombardo MV, Chakrabarti B, Lai MC. Self-referential and social cognition in a case of autism and agenesis of the corpus callosum. Mol Autism 2012; 3:14. [PMID: 23171505 PMCID: PMC3522057 DOI: 10.1186/2040-2392-3-14] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2012] [Accepted: 10/30/2012] [Indexed: 01/23/2023] Open
Abstract
UNLABELLED BACKGROUND While models of autism spectrum conditions (ASC) are emerging at the genetic level of analysis, clear models at higher levels of analysis, such as neuroanatomy, are lacking. Here we examine agenesis of the corpus callosum (AgCC) as a model at the level of neuroanatomy that may be relevant for understanding self-referential and social-cognitive difficulties in ASC. METHODS We examined performance on a wide array of tests in self-referential and social-cognitive domains in a patient with both AgCC and a diagnosis of ASC. Tests included a depth-of-processing memory paradigm with self-referential and social-cognitive manipulations, self-report measures of self-consciousness, alexithymia, and empathy, as well as performance measures of first-person pronoun usage and mentalizing ability. The performance of the AgCC patient was compared to a group of individuals with ASC but without AgCC and with neurotypical controls. These comparison groups come from a prior study where group differences were apparent across many measures. We used bootstrapping to assess whether the AgCC patient exhibited scores that were within or outside the 95% bias-corrected and accelerated bootstrap confidence intervals observed in both comparison groups. RESULTS Within the depth-of-processing memory paradigm, the AgCC patient showed decreased memory sensitivity that was more extreme than both comparison groups across all conditions. The patient's most pronounced difficulty on this task emerged in the social-cognitive domain related to information-processing about other people. The patient was similar to the ASC group in benefiting less from self-referential processing compared to the control group. Across a variety of other self-referential (i.e. alexithymia, private self-consciousness) and social-cognitive measures (i.e. self-reported imaginative and perspective-taking subscales of empathy, mentalizing), the AgCC patient also showed more extreme scores than those observed for both of the comparison groups. However, the AgCC patient scored within the range observed in the comparison groups on measures of first-person pronoun usage and self-reported affective empathy subscales. CONCLUSIONS We conclude that AgCC co-occurring with a diagnosis of ASC may be a relevant model at the level of neuroanatomy for understanding mechanisms involved in self-referential and high-level social-cognitive difficulties in ASC.
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Affiliation(s)
- Michael V Lombardo
- Autism Research Centre, Department of Psychiatry, University of Cambridge, Douglas House, 18B Trumpington Road, Cambridge CB2 8AH, UK
| | - Bhismadev Chakrabarti
- Autism Research Centre, Department of Psychiatry, University of Cambridge, Douglas House, 18B Trumpington Road, Cambridge CB2 8AH, UK
- Centre for Integrative Neuroscience and Neurodynamics, School of Psychology and Clinical Language Sciences, University of Reading, Whiteknights RG6 6AL, UK
| | - Meng-Chuan Lai
- Autism Research Centre, Department of Psychiatry, University of Cambridge, Douglas House, 18B Trumpington Road, Cambridge CB2 8AH, UK
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57
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Konopka G, Friedrich T, Davis-Turak J, Winden K, Oldham MC, Gao F, Chen L, Wang GZ, Luo R, Preuss TM, Geschwind DH. Human-specific transcriptional networks in the brain. Neuron 2012; 75:601-17. [PMID: 22920253 DOI: 10.1016/j.neuron.2012.05.034] [Citation(s) in RCA: 173] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/31/2012] [Indexed: 12/25/2022]
Abstract
Understanding human-specific patterns of brain gene expression and regulation can provide key insights into human brain evolution and speciation. Here, we use next-generation sequencing, and Illumina and Affymetrix microarray platforms, to compare the transcriptome of human, chimpanzee, and macaque telencephalon. Our analysis reveals a predominance of genes differentially expressed within human frontal lobe and a striking increase in transcriptional complexity specific to the human lineage in the frontal lobe. In contrast, caudate nucleus gene expression is highly conserved. We also identify gene coexpression signatures related to either neuronal processes or neuropsychiatric diseases, including a human-specific module with CLOCK as its hub gene and another module enriched for neuronal morphological processes and genes coexpressed with FOXP2, a gene important for language evolution. These data demonstrate that transcriptional networks have undergone evolutionary remodeling even within a given brain region, providing a window through which to view the foundation of uniquely human cognitive capacities.
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Affiliation(s)
- Genevieve Konopka
- Department of Neurology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA 90095, USA.
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58
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Blaker-Lee A, Gupta S, McCammon JM, De Rienzo G, Sive H. Zebrafish homologs of genes within 16p11.2, a genomic region associated with brain disorders, are active during brain development, and include two deletion dosage sensor genes. Dis Model Mech 2012; 5:834-51. [PMID: 22566537 PMCID: PMC3484866 DOI: 10.1242/dmm.009944] [Citation(s) in RCA: 68] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2012] [Accepted: 04/25/2012] [Indexed: 01/19/2023] Open
Abstract
Deletion or duplication of one copy of the human 16p11.2 interval is tightly associated with impaired brain function, including autism spectrum disorders (ASDs), intellectual disability disorder (IDD) and other phenotypes, indicating the importance of gene dosage in this copy number variant region (CNV). The core of this CNV includes 25 genes; however, the number of genes that contribute to these phenotypes is not known. Furthermore, genes whose functional levels change with deletion or duplication (termed 'dosage sensors'), which can associate the CNV with pathologies, have not been identified in this region. Using the zebrafish as a tool, a set of 16p11.2 homologs was identified, primarily on chromosomes 3 and 12. Use of 11 phenotypic assays, spanning the first 5 days of development, demonstrated that this set of genes is highly active, such that 21 out of the 22 homologs tested showed loss-of-function phenotypes. Most genes in this region were required for nervous system development - impacting brain morphology, eye development, axonal density or organization, and motor response. In general, human genes were able to substitute for the fish homolog, demonstrating orthology and suggesting conserved molecular pathways. In a screen for 16p11.2 genes whose function is sensitive to hemizygosity, the aldolase a (aldoaa) and kinesin family member 22 (kif22) genes were identified as giving clear phenotypes when RNA levels were reduced by ∼50%, suggesting that these genes are deletion dosage sensors. This study leads to two major findings. The first is that the 16p11.2 region comprises a highly active set of genes, which could present a large genetic target and might explain why multiple brain function, and other, phenotypes are associated with this interval. The second major finding is that there are (at least) two genes with deletion dosage sensor properties among the 16p11.2 set, and these could link this CNV to brain disorders such as ASD and IDD.
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Affiliation(s)
- Alicia Blaker-Lee
- Whitehead Institute for Biomedical Research, Nine Cambridge Center, Cambridge, MA 02142, USA
| | - Sunny Gupta
- Whitehead Institute for Biomedical Research, Nine Cambridge Center, Cambridge, MA 02142, USA
| | - Jasmine M. McCammon
- Whitehead Institute for Biomedical Research, Nine Cambridge Center, Cambridge, MA 02142, USA
| | - Gianluca De Rienzo
- Whitehead Institute for Biomedical Research, Nine Cambridge Center, Cambridge, MA 02142, USA
| | - Hazel Sive
- Whitehead Institute for Biomedical Research, Nine Cambridge Center, Cambridge, MA 02142, USA
- Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, USA
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59
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Freitas BCG, Trujillo CA, Carromeu C, Yusupova M, Herai RH, Muotri AR. Stem cells and modeling of autism spectrum disorders. Exp Neurol 2012; 260:33-43. [PMID: 23036599 DOI: 10.1016/j.expneurol.2012.09.017] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2012] [Accepted: 09/24/2012] [Indexed: 01/21/2023]
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.
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Affiliation(s)
- Beatriz C G Freitas
- University of California San Diego, School of Medicine, Department of Pediatrics/Rady Children's Hospital San Diego, Department of Cellular & Molecular Medicine, Stem Cell Program, La Jolla, CA 92093, MC 0695, USA
| | - Cleber A Trujillo
- University of California San Diego, School of Medicine, Department of Pediatrics/Rady Children's Hospital San Diego, Department of Cellular & Molecular Medicine, Stem Cell Program, La Jolla, CA 92093, MC 0695, USA
| | - Cassiano Carromeu
- University of California San Diego, School of Medicine, Department of Pediatrics/Rady Children's Hospital San Diego, Department of Cellular & Molecular Medicine, Stem Cell Program, La Jolla, CA 92093, MC 0695, USA
| | - Marianna Yusupova
- University of California San Diego, School of Medicine, Department of Pediatrics/Rady Children's Hospital San Diego, Department of Cellular & Molecular Medicine, Stem Cell Program, La Jolla, CA 92093, MC 0695, USA
| | - Roberto H Herai
- University of California San Diego, School of Medicine, Department of Pediatrics/Rady Children's Hospital San Diego, Department of Cellular & Molecular Medicine, Stem Cell Program, La Jolla, CA 92093, MC 0695, USA
| | - Alysson R Muotri
- University of California San Diego, School of Medicine, Department of Pediatrics/Rady Children's Hospital San Diego, Department of Cellular & Molecular Medicine, Stem Cell Program, La Jolla, CA 92093, MC 0695, USA.
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60
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Brielmaier J, Matteson PG, Silverman JL, Senerth JM, Kelly S, Genestine M, Millonig JH, DiCicco-Bloom E, Crawley JN. Autism-relevant social abnormalities and cognitive deficits in engrailed-2 knockout mice. PLoS One 2012; 7:e40914. [PMID: 22829897 PMCID: PMC3400671 DOI: 10.1371/journal.pone.0040914] [Citation(s) in RCA: 119] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2012] [Accepted: 06/15/2012] [Indexed: 12/20/2022] Open
Abstract
ENGRAILED 2 (En2), a homeobox transcription factor, functions as a patterning gene in the early development and connectivity of rodent hindbrain and cerebellum, and regulates neurogenesis and development of monoaminergic pathways. To further understand the neurobiological functions of En2, we conducted neuroanatomical expression profiling of En2 wildtype mice. RTQPCR assays demonstrated that En2 is expressed in adult brain structures including the somatosensory cortex, hippocampus, striatum, thalamus, hypothalamus and brainstem. Human genetic studies indicate that EN2 is associated with autism. To determine the consequences of En2 mutations on mouse behaviors, including outcomes potentially relevant to autism, we conducted comprehensive phenotyping of social, communication, repetitive, and cognitive behaviors. En2 null mutants exhibited robust deficits in reciprocal social interactions as juveniles and adults, and absence of sociability in adults, replicated in two independent cohorts. Fear conditioning and water maze learning were impaired in En2 null mutants. High immobility in the forced swim test, reduced prepulse inhibition, mild motor coordination impairments and reduced grip strength were detected in En2 null mutants. No genotype differences were found on measures of ultrasonic vocalizations in social contexts, and no stereotyped or repetitive behaviors were observed. Developmental milestones, general health, olfactory abilities, exploratory locomotor activity, anxiety-like behaviors and pain responses did not differ across genotypes, indicating that the behavioral abnormalities detected in En2 null mutants were not attributable to physical or procedural confounds. Our findings provide new insight into the role of En2 in complex behaviors and suggest that disturbances in En2 signaling may contribute to neuropsychiatric disorders marked by social and cognitive deficits, including autism spectrum disorders.
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Affiliation(s)
- Jennifer Brielmaier
- Laboratory of Behavioral Neuroscience, National Institute of Mental Health, Bethesda, Maryland, USA.
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61
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Modeling human cortical development in vitro using induced pluripotent stem cells. Proc Natl Acad Sci U S A 2012; 109:12770-5. [PMID: 22761314 DOI: 10.1073/pnas.1202944109] [Citation(s) in RCA: 366] [Impact Index Per Article: 30.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Human induced pluripotent stem cells (hiPSCs) are emerging as a tool for understanding human brain development at cellular, molecular, and genomic levels. Here we show that hiPSCs grown in suspension in the presence of rostral neuralizing factors can generate 3D structures containing polarized radial glia, intermediate progenitors, and a spectrum of layer-specific cortical neurons reminiscent of their organization in vivo. The hiPSC-derived multilayered structures express a gene expression profile typical of the embryonic telencephalon but not that of other CNS regions. Their transcriptome is highly enriched in transcription factors controlling the specification, growth, and patterning of the dorsal telencephalon and displays highest correlation with that of the early human cerebral cortical wall at 8-10 wk after conception. Thus, hiPSC are capable of enacting a transcriptional program specifying human telencephalic (pallial) development. This model will allow the study of human brain development as well as disorders of the human cerebral cortex.
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62
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Alsaif M, Guest PC, Schwarz E, Reif A, Kittel-Schneider S, Spain M, Rahmoune H, Bahn S. Analysis of serum and plasma identifies differences in molecular coverage, measurement variability, and candidate biomarker selection. Proteomics Clin Appl 2012; 6:297-303. [DOI: 10.1002/prca.201100061] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Murtada Alsaif
- Department of Chemical Engineering and Biotechnology; University of Cambridge; Cambridge UK
| | - Paul C. Guest
- Department of Chemical Engineering and Biotechnology; University of Cambridge; Cambridge UK
| | - Emanuel Schwarz
- Department of Chemical Engineering and Biotechnology; University of Cambridge; Cambridge UK
| | - Andreas Reif
- Department of Psychiatry; University of Würzburg; Germany
| | | | | | - Hassan Rahmoune
- Department of Chemical Engineering and Biotechnology; University of Cambridge; Cambridge UK
| | - Sabine Bahn
- Department of Chemical Engineering and Biotechnology; University of Cambridge; Cambridge UK
- Department of Neuroscience; Erasmus Medical Centre; Rotterdam Netherlands
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63
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Fogel BL, Wexler E, Wahnich A, Friedrich T, Vijayendran C, Gao F, Parikshak N, Konopka G, Geschwind DH. RBFOX1 regulates both splicing and transcriptional networks in human neuronal development. Hum Mol Genet 2012; 21:4171-86. [PMID: 22730494 DOI: 10.1093/hmg/dds240] [Citation(s) in RCA: 152] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
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.
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Affiliation(s)
- Brent L Fogel
- Program in Neurogenetics, Department of Neurology, David Geffen School of Medicine, University of California at Los Angeles, Los Angeles, CA 90095, USA.
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64
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Fischer U, Keller A, Voss M, Backes C, Welter C, Meese E. Genome-wide gene amplification during differentiation of neural progenitor cells in vitro. PLoS One 2012; 7:e37422. [PMID: 22606362 PMCID: PMC3351388 DOI: 10.1371/journal.pone.0037422] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2012] [Accepted: 04/19/2012] [Indexed: 01/06/2023] Open
Abstract
DNA sequence amplification is a phenomenon that occurs predictably at defined stages during normal development in some organisms. Developmental gene amplification was first described in amphibians during gametogenesis and has not yet been described in humans. To date gene amplification in humans is a hallmark of many tumors. We used array-CGH (comparative genomic hybridization) and FISH (fluorescence in situ hybridization) to discover gene amplifications during in vitro differentiation of human neural progenitor cells. Here we report a complex gene amplification pattern two and five days after induction of differentiation of human neural progenitor cells. We identified several amplified genes in neural progenitor cells that are known to be amplified in malignant tumors. There is also a striking overlap of amplified chromosomal regions between differentiating neural progenitor cells and malignant tumor cells derived from astrocytes. Gene amplifications in normal human cells as physiological process has not been reported yet and may bear resemblance to developmental gene amplifications in amphibians and insects.
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Affiliation(s)
- Ulrike Fischer
- Department of Human Genetics, Saarland University, Homburg/Saar, Germany.
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65
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Peñagarikano O, Geschwind DH. What does CNTNAP2 reveal about autism spectrum disorder? Trends Mol Med 2012; 18:156-63. [PMID: 22365836 PMCID: PMC3633421 DOI: 10.1016/j.molmed.2012.01.003] [Citation(s) in RCA: 116] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2011] [Revised: 01/07/2012] [Accepted: 01/10/2012] [Indexed: 01/02/2023]
Abstract
Autism spectrum disorder (ASD) is a phenotypically and genetically heterogeneous condition characterized by the presence of repetitive/restrictive behaviors and variable deficits in language and social behavior. Many genes predisposing an individual to ASD have been identified, and understanding the causal disease mechanism(s) is critical to be able to develop treatments. Neurobiological, genetic, and imaging data provide strong evidence for the CNTNAP2 gene as a risk factor for ASD and related neurodevelopmental disorders. This review discusses the clinical genetics and current understanding of the biology of CNTNAP2 as related to ASD and illustrates how the integration of multiple research approaches, from human studies to animal models, converge to inform functional biology focused on novel treatment development.
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Affiliation(s)
- Olga Peñagarikano
- Program in Neurogenetics, Department of Neurology, David Geffen School of Medicine, University of California, Los Angeles, CA 90095, USA
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Regulation of MET by FOXP2, genes implicated in higher cognitive dysfunction and autism risk. J Neurosci 2011; 31:11437-42. [PMID: 21832174 DOI: 10.1523/jneurosci.0181-11.2011] [Citation(s) in RCA: 73] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Autism spectrum disorder (ASD) is a highly heritable, behaviorally defined, heterogeneous disorder of unknown pathogenesis. Several genetic risk genes have been identified, including the gene encoding the receptor tyrosine kinase MET, which regulates neuronal differentiation and growth. An ASD-associated polymorphism disrupts MET gene transcription, and there are reduced levels of MET protein expression in the mature temporal cortex of subjects with ASD. To address the possible neurodevelopmental contribution of MET to ASD pathogenesis, we examined the expression and transcriptional regulation of MET by a transcription factor, FOXP2, which is implicated in regulation of cognition and language, two functions altered in ASD. MET mRNA expression in the midgestation human fetal cerebral cortex is strikingly restricted, localized to portions of the temporal and occipital lobes. Within the cortical plate of the temporal lobe, the pattern of MET expression is highly complementary to the expression pattern of FOXP2, suggesting the latter may play a role in repression of gene expression. Consistent with this, MET and FOXP2 also are reciprocally expressed by differentiating normal human neuronal progenitor cells (NHNPs) in vitro, leading us to assess whether FOXP2 transcriptionally regulates MET. Indeed, FOXP2 binds directly to the 5' regulatory region of MET, and overexpression of FOXP2 results in transcriptional repression of MET. The expression of MET in restricted human neocortical regions, and its regulation in part by FOXP2, is consistent with genetic evidence for MET contributing to ASD risk.
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