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Hakizimana O, Hitayezu J, Uyisenga JP, Onohuean H, Palmeira L, Bours V, Alagbonsi AI, Uwineza A. Genetic etiology of autism spectrum disorder in the African population: a scoping review. Front Genet 2024; 15:1431093. [PMID: 39391062 PMCID: PMC11464363 DOI: 10.3389/fgene.2024.1431093] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2024] [Accepted: 08/28/2024] [Indexed: 10/12/2024] Open
Abstract
Background Autism spectrum disorder (ASD) is a neurodevelopmental disorder (NDD) characterized by significant impairments in social, communicative, and behavioral abilities. However, only a limited number of studies address the genetic basis of ASD in the African population. This study aims to document the genes associated with ASD in Africa and the techniques used to identify them. Additionally, genes identified elsewhere but not yet in Africa are also noted. Methods Online databases such as Wiley Online Library, PubMed, and Africa Journal Online were used. The review was conducted using the keyword related to genetic and genomic ASD study in the African population. Result In this scoping review, 40 genetic studies on ASD in Africa were reviewed. The Egyptian and South African populations were the most studied, with 25 and 5 studies, respectively. Countries with fewer studies included Tunisia (4), East African countries (3), Libya (1), Nigeria (1), and Morocco (1). Some 61 genes responsible for ASD were identified in the African population: 26 were identified using a polymerase chain reaction (PCR)-based method, 22 were identified using sequencing technologies, and 12 genes and one de novo chromosomal aberration were identified through other techniques. No African study identified any ASD gene with genome-wide association studies (GWAS). Notably, at least 20 ASD risk genes reported in non-African countries were yet to be confirmed in Africa's population. Conclusion There are insufficient genetic studies on ASD in the African population, with sample size being a major limitation in most genetic association studies, leading to inconclusive results. Thus, there is a need to conduct more studies with large sample sizes to identify other genes associated with ASD in Africa's population using high-throughput sequencing technology.
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Affiliation(s)
- Olivier Hakizimana
- Department of Biochemistry, Molecular Biology and Genetics, School of Medicine and Pharmacy, College of Medicine and Health Sciences, University of Rwanda, Kigali, Rwanda
- Center for Human Genetics, Centre Hospitalier Universitaire Sart-Tilman, University of Liege, Liege, Belgium
| | - Janvier Hitayezu
- Department of Pediatrics, University Teaching Hospital of Kigali (CHUK), Kigali, Rwanda
| | - Jeanne P. Uyisenga
- Department of Biology, College of Science and Technology, University of Rwanda, Kigali, Rwanda
| | - Hope Onohuean
- Biopharmaceutics Unit, Department of Pharmacology and Toxicology, School of Pharmacy, Kampala International University, Bushenyi, Uganda
| | - Leonor Palmeira
- Center for Human Genetics, Centre Hospitalier Universitaire Sart-Tilman, University of Liege, Liege, Belgium
| | - Vincent Bours
- Center for Human Genetics, Centre Hospitalier Universitaire Sart-Tilman, University of Liege, Liege, Belgium
| | - Abdullateef Isiaka Alagbonsi
- Department of Physiology, School of Medicine and Pharmacy, College of Medicine and Health Sciences, University of Rwanda, Kigali, Rwanda
| | - Annette Uwineza
- Department of Biochemistry, Molecular Biology and Genetics, School of Medicine and Pharmacy, College of Medicine and Health Sciences, University of Rwanda, Kigali, Rwanda
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2
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Holme JA, Myhre O, Øvrevik J. Adverse neurodevelopment in children associated with prenatal exposure to fine particulate matter (PM 2.5) - Possible roles of polycyclic aromatic hydrocarbons (PAHs) and mechanisms involved. Reprod Toxicol 2024:108718. [PMID: 39276806 DOI: 10.1016/j.reprotox.2024.108718] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2024] [Revised: 09/11/2024] [Accepted: 09/11/2024] [Indexed: 09/17/2024]
Abstract
Prenatal exposure to ambient fine particles (PM2.5) and polycyclic aromatic hydrocarbons (PAHs) has been associated with adverse birth outcomes including neurodevelopmental effects with cognitive and/or behavioral implications in early childhood. As a background we first briefly summarize human studies on PM2.5 and PAHs associated with adverse birth outcomes and modified neurodevelopment. Next, we add more specific information from animal studies and in vitro studies and elucidate possible biological mechanisms. More specifically we focus on the potential role of PAHs attached to PM2.5 and explore whether effects of these compounds may arise from disturbance of placental function or more directly by interfering with neurodevelopmental processes in the fetal brain. Possible molecular initiating events (MIEs) include interactions with cellular receptors such as the aryl hydrocarbon receptor (AhR), beta-adrenergic receptors (βAR) and transient receptor potential (TRP)-channels resulting in altered gene expression. MIE linked to the binding of PAHs to cytochrome P450 (CYP) enzymes and formation of reactive electrophilic metabolites are likely less important. The experimental animal and in vitro studies support the epidemiological findings and suggest steps involved in mechanistic pathways explaining the associations. An overall evaluation of the doses/concentrations used in experimental studies combined with the mechanistic understanding further supports the hypothesis that prenatal PAHs exposure may cause adverse outcomes (AOs) linked to human neurodevelopment. Several MIEs will likely occur simultaneously in various cells/tissues involving several key events (KEs) which relative importance will depend on dose, time, tissue, genetics, other environmental factors, and neurodevelopmental endpoint in study.
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Affiliation(s)
- Jørn A Holme
- Department of Air quality and Noise, Division of Climate and Environmental Health, Norwegian Institute of Public Health, PO Box PO Box 222 Skøyen, 0213 Oslo, Norway.
| | - Oddvar Myhre
- Department of Chemical Toxicology, Division of Climate and Environmental Health, Norwegian Institute of Public Health, PO Box PO Box 222 Skøyen, 0213 Oslo, Norway
| | - Johan Øvrevik
- Department of Biosciences, Faculty of Mathematics and Natural Sciences, University of Oslo, PO Box 1066 Blindern, 0316 Oslo, Norway; Division of Climate and Environmental Health, Norwegian Institute of Public Health, PO Box 222 Skøyen 0213 Oslo, Norway
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3
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Wang Z, Ji Y, Fu Y, Liu F, Du X, Liu H, Zhu W, Xue K, Qin W, Zhang Q. Gene expression associated with human brain activations in facial expression recognition. Brain Imaging Behav 2022; 16:1657-1670. [PMID: 35212890 DOI: 10.1007/s11682-022-00633-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/10/2022] [Indexed: 11/30/2022]
Abstract
Previous studies identified some genetic loci of emotion, but few focused on human emotion-related gene expression. In this study, the facial expression recognition (FER) task-based high-resolution fMRI data of 203 subjects in the Human Connectome Project (HCP) and expression data of the six healthy human postmortem brain tissues in the Allen Human Brain Atlas (AHBA) were used to conduct a transcriptome-neuroimaging spatial association analysis. Finally, 371 genes were identified to be significantly associated with FER-related brain activations. Enrichment analyses revealed that FER-related genes were mainly expressed in the brain, especially neurons, and might be related to cell junction organization, synaptic functions, and nervous system development regulation, indicating that FER was a complex polygenetic biological process involving multiple pathways. Moreover, these genes exhibited higher enrichment for psychiatric diseases with heavy emotion impairments. This study provided new insight into understanding the FER-related biological mechanisms and might be helpful to explore treatment methods for emotion-related psychiatric disorders.
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Affiliation(s)
- Zirui Wang
- Department of Medical imaging and Tianjin Key Laboratory of Functional Imaging, Tianjin Medical University General Hospital, No. 154, Anshan Road, Heping District, Tianjin, 300052, China
| | - Yuan Ji
- Department of Medical imaging and Tianjin Key Laboratory of Functional Imaging, Tianjin Medical University General Hospital, No. 154, Anshan Road, Heping District, Tianjin, 300052, China
| | - Yumeng Fu
- Department of Medical imaging and Tianjin Key Laboratory of Functional Imaging, Tianjin Medical University General Hospital, No. 154, Anshan Road, Heping District, Tianjin, 300052, China
| | - Feng Liu
- Department of Medical imaging and Tianjin Key Laboratory of Functional Imaging, Tianjin Medical University General Hospital, No. 154, Anshan Road, Heping District, Tianjin, 300052, China
| | - Xin Du
- Department of Medical imaging and Tianjin Key Laboratory of Functional Imaging, Tianjin Medical University General Hospital, No. 154, Anshan Road, Heping District, Tianjin, 300052, China
| | - Huaigui Liu
- Department of Medical imaging and Tianjin Key Laboratory of Functional Imaging, Tianjin Medical University General Hospital, No. 154, Anshan Road, Heping District, Tianjin, 300052, China
| | - Wenshuang Zhu
- Department of Medical imaging and Tianjin Key Laboratory of Functional Imaging, Tianjin Medical University General Hospital, No. 154, Anshan Road, Heping District, Tianjin, 300052, China
| | - Kaizhong Xue
- Department of Medical imaging and Tianjin Key Laboratory of Functional Imaging, Tianjin Medical University General Hospital, No. 154, Anshan Road, Heping District, Tianjin, 300052, China
| | - Wen Qin
- Department of Medical imaging and Tianjin Key Laboratory of Functional Imaging, Tianjin Medical University General Hospital, No. 154, Anshan Road, Heping District, Tianjin, 300052, China
| | - Quan Zhang
- Department of Medical imaging and Tianjin Key Laboratory of Functional Imaging, Tianjin Medical University General Hospital, No. 154, Anshan Road, Heping District, Tianjin, 300052, China.
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4
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Jones KL, Pride MC, Edmiston E, Yang M, Silverman JL, Crawley JN, Van de Water J. Autism-specific maternal autoantibodies produce behavioral abnormalities in an endogenous antigen-driven mouse model of autism. Mol Psychiatry 2020; 25:2994-3009. [PMID: 29955164 PMCID: PMC6310680 DOI: 10.1038/s41380-018-0126-1] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/19/2018] [Revised: 05/25/2018] [Accepted: 06/05/2018] [Indexed: 01/05/2023]
Abstract
Immune dysregulation has been noted consistently in individuals with autism spectrum disorder (ASD) and their families, including the presence of autoantibodies reactive to fetal brain proteins in nearly a quarter of mothers of children with ASD versus <1% in mothers of typically developing children. Our lab recently identified the peptide epitope sequences on seven antigenic proteins targeted by these maternal autoantibodies. Through immunization with these peptide epitopes, we have successfully created an endogenous, antigen-driven mouse model that ensures a constant exposure to the salient autoantibodies throughout gestation in C57BL/6J mice. This exposure more naturally mimics what is observed in mothers of children with ASD. Male and female offspring were tested using a comprehensive sequence of behavioral assays, as well as measures of health and development highly relevant to ASD. We found that MAR-ASD male and female offspring had significant alterations in development and social interactions during dyadic play. Although 3-chambered social approach was not significantly different, fewer social interactions with an estrous female were noted in the adult male MAR-ASD animals, as well as reduced vocalizations emitted in response to social cues with robust repetitive self-grooming behaviors relative to saline treated controls. The generation of MAR-ASD-specific epitope autoantibodies in female mice prior to breeding created a model that demonstrates for the first time that ASD-specific antigen-induced maternal autoantibodies produced alterations in a constellation of ASD-relevant behaviors.
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Affiliation(s)
- Karen L. Jones
- Department of Internal Medicine, Division of Rheumatology, Allergy, and Clinical Immunology, University of California, Davis, CA, USA,MIND Institute, University of California, Davis, CA, USA
| | - Michael C. Pride
- Department of Psychiatry and Behavioral Sciences, University of California, Davis, CA, USA
| | - Elizabeth Edmiston
- Department of Internal Medicine, Division of Rheumatology, Allergy, and Clinical Immunology, University of California, Davis, CA, USA
| | - Mu Yang
- Department of Psychiatry and Behavioral Sciences, University of California, Davis, CA, USA,Institute for Genomic Medicine, Columbia University Medical Center, New York, NY, USA
| | - Jill L. Silverman
- MIND Institute, University of California, Davis, CA, USA,Department of Psychiatry and Behavioral Sciences, University of California, Davis, CA, USA
| | - Jacqueline N. Crawley
- MIND Institute, University of California, Davis, CA, USA,Department of Psychiatry and Behavioral Sciences, University of California, Davis, CA, USA
| | - Judy Van de Water
- Department of Internal Medicine, Division of Rheumatology, Allergy, and Clinical Immunology, University of California, Davis, CA, USA. .,MIND Institute, University of California, Davis, CA, USA.
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5
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Kong XZ, Tzourio-Mazoyer N, Joliot M, Fedorenko E, Liu J, Fisher SE, Francks C. Gene Expression Correlates of the Cortical Network Underlying Sentence Processing. NEUROBIOLOGY OF LANGUAGE (CAMBRIDGE, MASS.) 2020; 1:77-103. [PMID: 36794006 PMCID: PMC9923707 DOI: 10.1162/nol_a_00004] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/10/2019] [Accepted: 12/19/2019] [Indexed: 04/16/2023]
Abstract
A pivotal question in modern neuroscience is which genes regulate brain circuits that underlie cognitive functions. However, the field is still in its infancy. Here we report an integrated investigation of the high-level language network (i.e., sentence-processing network) in the human cerebral cortex, combining regional gene expression profiles, task fMRI, large-scale neuroimaging meta-analysis, and resting-state functional network approaches. We revealed reliable gene expression-functional network correlations using three different network definition strategies, and identified a consensus set of genes related to connectivity within the sentence-processing network. The genes involved showed enrichment for neural development and actin-related functions, as well as association signals with autism, which can involve disrupted language functioning. Our findings help elucidate the molecular basis of the brain's infrastructure for language. The integrative approach described here will be useful for studying other complex cognitive traits.
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Affiliation(s)
| | - Nathalie Tzourio-Mazoyer
- University of Bordeaux, GIN, IMN, UMR 5293, Bordeaux, France
- CNRS, GIN, IMN, UMR 5293, Bordeaux, France
- CEA, GIN, IMN, UMR 5293, Bordeaux, France
| | - Marc Joliot
- University of Bordeaux, GIN, IMN, UMR 5293, Bordeaux, France
- CNRS, GIN, IMN, UMR 5293, Bordeaux, France
- CEA, GIN, IMN, UMR 5293, Bordeaux, France
| | - Evelina Fedorenko
- Department of Brain and Cognitive Sciences and McGovern Institute for Brain Research, MIT, Cambridge, MA, 02139, USA
| | - Jia Liu
- Faculty of Psychology, Beijing Normal University, Beijing 100875, China
| | - Simon E. Fisher
- Language and Genetics Department, Max Planck Institute for Psycholinguistics, Nijmegen, The Netherlands
- Donders Institute for Brain, Cognition and Behaviour, Radboud University, Nijmegen, The Netherlands
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6
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Ma X, Qiu S. Control of cortical synapse development and plasticity by MET receptor tyrosine kinase, a genetic risk factor for autism. J Neurosci Res 2019; 98:2115-2129. [PMID: 31746037 DOI: 10.1002/jnr.24542] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2019] [Revised: 10/04/2019] [Accepted: 10/04/2019] [Indexed: 12/27/2022]
Abstract
The key developmental milestone events of the human brain, such as neurogenesis, synapse formation, maturation, and plasticity, are determined by a myriad of molecular signaling events, including those mediated by a number of receptor tyrosine kinases (RTKs) and their cognate ligands. Aberrant or mistimed brain development and plasticity can lead to maladaptive changes, such as dysregulated synaptic connectivity and breakdown of circuit functions necessary for cognition and adaptive behaviors, which are hypothesized pathophysiologies of many neurodevelopmental and neuropsychiatric disorders. Here we review recent literature that supports autism spectrum disorder as a likely result of aberrant synapse development due to mistimed maturation and plasticity. We focus on MET RTK, a prominent genetic risk factor for autism, and discuss how a pleiotropic molecular signaling system engaged by MET exemplifies a genetic program that controls cortical circuit development and plasticity by modulating the anatomical and functional connectivity of cortical circuits, thus conferring genetic risk for neurodevelopmental disorders.
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Affiliation(s)
- Xiaokuang Ma
- Department of Basic Medical Sciences, University of Arizona College of Medicine-Phoenix, Phoenix, AZ, USA
| | - Shenfeng Qiu
- Department of Basic Medical Sciences, University of Arizona College of Medicine-Phoenix, Phoenix, AZ, USA
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7
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Jones KL, Van de Water J. Maternal autoantibody related autism: mechanisms and pathways. Mol Psychiatry 2019; 24:252-265. [PMID: 29934547 PMCID: PMC6784837 DOI: 10.1038/s41380-018-0099-0] [Citation(s) in RCA: 41] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/07/2017] [Revised: 04/12/2018] [Accepted: 04/23/2018] [Indexed: 12/16/2022]
Abstract
It has been estimated that autism spectrum disorder (ASD) now affects 1 in 59 children in the United States. Although the cause(s) of ASD remain largely unknown, it is becoming increasingly apparent that ASD can no longer be defined simply as a behavioral disorder, but is in effect a rather complex and highly heterogeneous biological disorder. Up until recently the brain was thought to be "immune privileged." However, it is now known that the immune system plays critical roles in the development and functioning of the brain throughout life. Recent evidence from multiple investigators has illustrated the deleterious role that dysregulation of the maternal immune system during gestation can play in the manifestation of changes in neurodevelopment, resulting in the development of neurobehavioral disorders such as ASD. One potential etiologic pathway through which the maternal immune system can interfere with neurodevelopment is through maternal autoantibodies that recognize proteins in the developing fetal brain. This mechanism of pathogenesis is now thought to lead to a subphenotype of ASD that has been termed maternal autoantibody related (MAR) ASD. This review provides an overview of the current research implicating the presence of brain-reactive maternal autoantibodies as a risk factor for MAR ASD.
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Affiliation(s)
- Karen L. Jones
- Rheumatology/Allergy and Clinical Immunology, University of California, 451 E. Health Sciences Drive, Suite 6510 GBSF, Davis, CA 95616, USA,The M.I.N.D. Institute, University of California, Davis, CA 95616, USA
| | - Judy Van de Water
- Rheumatology/Allergy and Clinical Immunology, University of California, 451 E. Health Sciences Drive, Suite 6510 GBSF, Davis, CA, 95616, USA. .,The M.I.N.D. Institute, University of California, Davis, CA, 95616, USA. .,NIEHS Center for Children's Environmental Health, University of California, Davis, CA, 95616, USA.
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8
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Ma X, Chen K, Lu Z, Piechowicz M, Liu Q, Wu J, Qiu S. Disruption of MET Receptor Tyrosine Kinase, an Autism Risk Factor, Impairs Developmental Synaptic Plasticity in the Hippocampus. Dev Neurobiol 2019; 79:36-50. [PMID: 30304576 PMCID: PMC6397659 DOI: 10.1002/dneu.22645] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2018] [Revised: 09/21/2018] [Accepted: 10/10/2018] [Indexed: 02/05/2023]
Abstract
As more genes conferring risks to neurodevelopmental disorders are identified, translating these genetic risk factors into biological mechanisms that impact the trajectory of the developing brain is a critical next step. Here, we report that disrupted signaling mediated MET receptor tyrosine kinase (RTK), an established risk factor for autism spectrum disorders, in the developing hippocampus glutamatergic circuit leads to profound deficits in neural development, synaptic transmission, and plasticity. In cultured hippocampus slices prepared from neonatal mice, pharmacological inhibition of MET kinase activity suppresses dendritic arborization and disrupts normal dendritic spine development. In addition, single-neuron knockdown (RNAi) or overexpression of Met in the developing hippocampal CA1 neurons leads to alterations, opposite in nature, in basal synaptic transmission and long-term plasticity. In forebrain-specific Met conditional knockout mice (Metfx/fx ;emx1cre ), an enhanced long-term potentiation (LTP) and long-term depression (LTD) were observed at early developmental stages (P12-14) at the Schaffer collateral to CA1 synapses compared with wild-type littermates. In contrast, LTP and LTD were markedly reduced at young adult stage (P56-70) during which wild-type mice show robust LTP and LTD. The altered trajectory of synaptic plasticity revealed by this study indicate that temporally regulated MET signaling as an intrinsic, cell autonomous, and pleiotropic mechanism not only critical for neuronal growth and functional maturation, but also for the timing of synaptic plasticity during forebrain glutamatergic circuits development.
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Affiliation(s)
- Xiaokuang Ma
- Basic Medical Sciences, University of Arizona College of Medicine-Phoenix, Phoenix, Arizona, 85004
- Department of Pharmacology, Shantou University Medical College, Shantou, Guangdong, 515041, China
| | - Ke Chen
- Basic Medical Sciences, University of Arizona College of Medicine-Phoenix, Phoenix, Arizona, 85004
- MOE Key Laboratory for NeuroInformation, The Clinical Hospital of Chengdu Brain Sciences Institute, University of Electronic Science and Technology of China, Chengdu, Sichuan, 610054, China
| | - Zhongming Lu
- Basic Medical Sciences, University of Arizona College of Medicine-Phoenix, Phoenix, Arizona, 85004
| | - Mariel Piechowicz
- Basic Medical Sciences, University of Arizona College of Medicine-Phoenix, Phoenix, Arizona, 85004
| | - Qiang Liu
- Barrow Neurological Institute, St. Joseph's Hospital Medical Center, Phoenix, Arizona, 85013
| | - Jie Wu
- Basic Medical Sciences, University of Arizona College of Medicine-Phoenix, Phoenix, Arizona, 85004
- Barrow Neurological Institute, St. Joseph's Hospital Medical Center, Phoenix, Arizona, 85013
- Department of Pharmacology, Shantou University Medical College, Shantou, Guangdong, 515041, China
| | - Shenfeng Qiu
- Basic Medical Sciences, University of Arizona College of Medicine-Phoenix, Phoenix, Arizona, 85004
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Tang S, Powell EM, Zhu W, Lo FS, Erzurumlu RS, Xu S. Altered Forebrain Functional Connectivity and Neurotransmission in a Kinase-Inactive Met Mouse Model of Autism. Mol Imaging 2019; 18:1536012118821034. [PMID: 30799683 PMCID: PMC6322103 DOI: 10.1177/1536012118821034] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2018] [Revised: 11/13/2018] [Accepted: 12/03/2018] [Indexed: 12/15/2022] Open
Abstract
MET, the gene encoding the tyrosine kinase receptor for hepatocyte growth factor, is a susceptibility gene for autism spectrum disorder (ASD). Genetically altered mice with a kinase-inactive Met offer a potential model for understanding neural circuit organization changes in autism. Here, we focus on the somatosensory thalamocortical circuitry because distinct somatosensory sensitivity phenotypes accompany ASD, and this system plays a major role in sensorimotor and social behaviors in mice. We employed resting-state functional magnetic resonance imaging and in vivo high-resolution proton MR spectroscopy to examine neuronal connectivity and neurotransmission of wild-type, heterozygous Met-Emx1, and fully inactive homozygous Met-Emx1 mice. Met-Emx1 brains showed impaired maturation of large-scale somatosensory network connectivity when compared with wild-type controls. Significant sex × genotype interaction in both network features and glutamate/gamma-aminobutyric acid (GABA) balance was observed. Female Met-Emx1 brains showed significant connectivity and glutamate/GABA balance changes in the somatosensory thalamocortical system when compared with wild-type brains. The glutamate/GABA ratio in the thalamus was correlated with the connectivity between the somatosensory cortex and the thalamus in heterozygous Met-Emx1 female brains. The findings support the hypothesis that aberrant functioning of the somatosensory thalamocortical system is at the core of the conspicuous somatosensory behavioral phenotypes observed in Met-Emx1 mice.
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Affiliation(s)
- Shiyu Tang
- Department of Diagnostic Radiology and Nuclear Medicine, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Elizabeth M. Powell
- Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, MD, USA
- National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, MD, USA
| | - Wenjun Zhu
- Department of Diagnostic Radiology and Nuclear Medicine, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Fu-Sun Lo
- Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Reha S. Erzurumlu
- Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Su Xu
- Department of Diagnostic Radiology and Nuclear Medicine, University of Maryland School of Medicine, Baltimore, MD, USA
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Kho ZY, Lal SK. The Human Gut Microbiome - A Potential Controller of Wellness and Disease. Front Microbiol 2018; 9:1835. [PMID: 30154767 PMCID: PMC6102370 DOI: 10.3389/fmicb.2018.01835] [Citation(s) in RCA: 554] [Impact Index Per Article: 92.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2018] [Accepted: 07/23/2018] [Indexed: 12/12/2022] Open
Abstract
Interest toward the human microbiome, particularly gut microbiome has flourished in recent decades owing to the rapidly advancing sequence-based screening and humanized gnotobiotic model in interrogating the dynamic operations of commensal microbiota. Although this field is still at a very preliminary stage, whereby the functional properties of the complex gut microbiome remain less understood, several promising findings have been documented and exhibit great potential toward revolutionizing disease etiology and medical treatments. In this review, the interactions between gut microbiota and the host have been focused on, to provide an overview of the role of gut microbiota and their unique metabolites in conferring host protection against invading pathogen, regulation of diverse host physiological functions including metabolism, development and homeostasis of immunity and the nervous system. We elaborate on how gut microbial imbalance (dysbiosis) may lead to dysfunction of host machineries, thereby contributing to pathogenesis and/or progression toward a broad spectrum of diseases. Some of the most notable diseases namely Clostridium difficile infection (infectious disease), inflammatory bowel disease (intestinal immune-mediated disease), celiac disease (multisystemic autoimmune disorder), obesity (metabolic disease), colorectal cancer, and autism spectrum disorder (neuropsychiatric disorder) have been discussed and delineated along with recent findings. Novel therapies derived from microbiome studies such as fecal microbiota transplantation, probiotic and prebiotics to target associated diseases have been reviewed to introduce the idea of how certain disease symptoms can be ameliorated through dysbiosis correction, thus revealing a new scientific approach toward disease treatment. Toward the end of this review, several research gaps and limitations have been described along with suggested future studies to overcome the current research lacunae. Despite the ongoing debate on whether gut microbiome plays a role in the above-mentioned diseases, we have in this review, gathered evidence showing a potentially far more complex link beyond the unidirectional cause-and-effect relationship between them.
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Affiliation(s)
- Zhi Y Kho
- School of Science, Tropical Medicine and Biology Platform, Monash University, Subang Jaya, Malaysia
| | - Sunil K Lal
- School of Science, Tropical Medicine and Biology Platform, Monash University, Subang Jaya, Malaysia
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11
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Hertz-Picciotto I, Schmidt RJ, Krakowiak P. Understanding environmental contributions to autism: Causal concepts and the state of science. Autism Res 2018; 11:554-586. [PMID: 29573218 DOI: 10.1002/aur.1938] [Citation(s) in RCA: 100] [Impact Index Per Article: 16.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2017] [Revised: 10/12/2017] [Accepted: 10/19/2017] [Indexed: 11/06/2022]
Abstract
The complexity of neurodevelopment, the rapidity of early neurogenesis, and over 100 years of research identifying environmental influences on neurodevelopment serve as backdrop to understanding factors that influence risk and severity of autism spectrum disorder (ASD). This Keynote Lecture, delivered at the May 2016 annual meeting of the International Society for Autism Research, describes concepts of causation, outlines the trajectory of research on nongenetic factors beginning in the 1960s, and briefly reviews the current state of this science. Causal concepts are introduced, including root causes; pitfalls in interpreting time trends as clues to etiologic factors; susceptible time windows for exposure; and implications of a multi-factorial model of ASD. An historical background presents early research into the origins of ASD. The epidemiologic literature from the last fifteen years is briefly but critically reviewed for potential roles of, for example, air pollution, pesticides, plastics, prenatal vitamins, lifestyle and family factors, and maternal obstetric and metabolic conditions during her pregnancy. Three examples from the case-control CHildhood Autism Risks from Genes and the Environment Study are probed to illustrate methodological approaches to central challenges in observational studies: capturing environmental exposure; causal inference when a randomized controlled clinical trial is either unethical or infeasible; and the integration of genetic, epigenetic, and environmental influences on development. We conclude with reflections on future directions, including exposomics, new technologies, the microbiome, gene-by-environment interaction in the era of -omics, and epigenetics as the interface of those two. As the environment is malleable, this research advances the goal of a productive and fulfilling life for all children, teen-agers and adults. Autism Res 2018, 11: 554-586. © 2018 International Society for Autism Research, Wiley Periodicals, Inc. LAY SUMMARY This Keynote Lecture, delivered at the 2016 meeting of the International Society for Autism Research, discusses evidence from human epidemiologic studies of prenatal factors contributing to autism, such as pesticides, maternal nutrition and her health. There is no single cause for autism. Examples highlight the features of a high-quality epidemiology study, and what comprises a compelling case for causation. Emergent research directions hold promise for identifying potential interventions to reduce disabilities, enhance giftedness, and improve lives of those with ASD.
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Affiliation(s)
- Irva Hertz-Picciotto
- Department of Public Health Sciences, MIND Institute (Medical Investigations of Neurodevelopmental Disorders), University of California, Davis, Davis, California
| | - Rebecca J Schmidt
- Department of Public Health Sciences, MIND Institute (Medical Investigations of Neurodevelopmental Disorders), University of California, Davis, Davis, California
| | - Paula Krakowiak
- Department of Public Health Sciences, MIND Institute (Medical Investigations of Neurodevelopmental Disorders), University of California, Davis, Davis, California
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12
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Heun-Johnson H, Levitt P. Differential impact of Met receptor gene interaction with early-life stress on neuronal morphology and behavior in mice. Neurobiol Stress 2017; 8:10-20. [PMID: 29255778 PMCID: PMC5723381 DOI: 10.1016/j.ynstr.2017.11.003] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2017] [Revised: 11/24/2017] [Accepted: 11/25/2017] [Indexed: 01/01/2023] Open
Abstract
Early adversity in childhood increases the risk of anxiety, mood, and post-traumatic stress disorders in adulthood, and specific gene-by-environment interactions may increase risk further. A common functional variant in the promoter region of the gene encoding the human MET receptor tyrosine kinase (rs1858830 ‘C’ allele) reduces expression of MET and is associated with altered cortical circuit function and structural connectivity. Mice with reduced Met expression exhibit changes in anxiety-like and conditioned fear behavior, precocious synaptic maturation in the hippocampus, and reduced neuronal arbor complexity and synaptogenesis. These phenotypes also can be produced independently by early adversity in wild-type mice. The present study addresses the outcome of combining early-life stress and genetic influences that alter timing of maturation on enduring functional and structural phenotypes. Using a model of reduced Met expression (Met+/−) and early-life stress from postnatal day 2–9, social, anxiety-like, and contextual fear behaviors in later life were measured. Mice that experienced early-life stress exhibited impairments in social interaction, whereas alterations in anxiety-like behavior and fear learning were driven by Met haploinsufficiency, independent of rearing condition. Early-life stress or reduced Met expression decreased arbor complexity of ventral hippocampal CA1 pyramidal neurons projecting to basolateral amygdala. Paradoxically, arbor complexity in Met+/− mice was increased following early-life stress, and thus not different from arbors in wild-type mice raised in control conditions. The changes in dendritic morphology are consistent with the hypothesis that the physiological state of maturation of CA1 neurons in Met+/− mice influences their responsiveness to early-life stress. The dissociation of behavioral and structural changes suggests that there may be phenotype-specific sensitivities to early-life stress.
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Affiliation(s)
- Hanke Heun-Johnson
- Neuroscience Graduate Program, University of Southern California, Los Angeles, CA, USA
| | - Pat Levitt
- Institute for the Developing Mind, Children's Hospital Los Angeles, Los Angeles, CA, USA.,Department of Pediatrics, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA
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13
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Eagleson KL, Xie Z, Levitt P. The Pleiotropic MET Receptor Network: Circuit Development and the Neural-Medical Interface of Autism. Biol Psychiatry 2017; 81:424-433. [PMID: 27837921 PMCID: PMC5285483 DOI: 10.1016/j.biopsych.2016.08.035] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/01/2016] [Revised: 08/11/2016] [Accepted: 08/28/2016] [Indexed: 02/07/2023]
Abstract
People with autism spectrum disorder and other neurodevelopmental disorders (NDDs) are behaviorally and medically heterogeneous. The combination of polygenicity and gene pleiotropy-the influence of one gene on distinct phenotypes-raises questions of how specific genes and their protein products interact to contribute to NDDs. A preponderance of evidence supports developmental and pathophysiological roles for the MET receptor tyrosine kinase, a multifunctional receptor that mediates distinct biological responses depending upon cell context. MET influences neuron architecture and synapse maturation in the forebrain and regulates homeostasis in gastrointestinal and immune systems, both commonly disrupted in NDDs. Peak expression of synapse-enriched MET is conserved across rodent and primate forebrain, yet regional differences in primate neocortex are pronounced, with enrichment in circuits that participate in social information processing. A functional risk allele in the MET promoter, enriched in subgroups of children with autism spectrum disorder, reduces transcription and disrupts socially relevant neural circuits structurally and functionally. In mice, circuit-specific deletion of Met causes distinct atypical behaviors. MET activation increases dendritic complexity and nascent synapse number, but synapse maturation requires reductions in MET. MET mediates its specific biological effects through different intracellular signaling pathways and has a complex protein interactome that is enriched in autism spectrum disorder and other NDD candidates. The interactome is coregulated in developing human neocortex. We suggest that a gene as pleiotropic and highly regulated as MET, together with its interactome, is biologically relevant in normal and pathophysiological contexts, affecting central and peripheral phenotypes that contribute to NDD risk and clinical symptoms.
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Affiliation(s)
- Kathie L Eagleson
- Program in Developmental Neurogenetics, Institute for the Developing Mind Children's Hospital Los Angeles, CA; Department of Pediatrics, Keck School of Medicine of University of Southern California, Los Angeles, CA
| | - Zhihui Xie
- Program in Developmental Neurogenetics, Institute for the Developing Mind Children's Hospital Los Angeles, CA
| | - Pat Levitt
- Program in Developmental Neurogenetics, Institute for the Developing Mind Children's Hospital Los Angeles, CA; Department of Pediatrics, Keck School of Medicine of University of Southern California, Los Angeles, CA.
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14
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Meltzer A, Van de Water J. The Role of the Immune System in Autism Spectrum Disorder. Neuropsychopharmacology 2017; 42:284-298. [PMID: 27534269 PMCID: PMC5143489 DOI: 10.1038/npp.2016.158] [Citation(s) in RCA: 305] [Impact Index Per Article: 43.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/09/2016] [Revised: 08/02/2016] [Accepted: 08/05/2016] [Indexed: 02/07/2023]
Abstract
Autism is a neurodevelopmental disorder characterized by deficits in communication and social skills as well as repetitive and stereotypical behaviors. While much effort has focused on the identification of genes associated with autism, research emerging within the past two decades suggests that immune dysfunction is a viable risk factor contributing to the neurodevelopmental deficits observed in autism spectrum disorders (ASD). Further, it is the heterogeneity within this disorder that has brought to light much of the current thinking regarding the subphenotypes within ASD and how the immune system is associated with these distinctions. This review will focus on the two main axes of immune involvement in ASD, namely dysfunction in the prenatal and postnatal periods. During gestation, prenatal insults including maternal infection and subsequent immunological activation may increase the risk of autism in the child. Similarly, the presence of maternally derived anti-brain autoantibodies found in ~20% of mothers whose children are at risk for developing autism has defined an additional subphenotype of ASD. The postnatal environment, on the other hand, is characterized by related but distinct profiles of immune dysregulation, inflammation, and endogenous autoantibodies that all persist within the affected individual. Further definition of the role of immune dysregulation in ASD thus necessitates a deeper understanding of the interaction between both maternal and child immune systems, and the role they have in diagnosis and treatment.
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Affiliation(s)
- Amory Meltzer
- Division of Rheumatology/Allergy and Clinical Immunology, Department of Internal Medicine, University of California, Davis, CA, USA
| | - Judy Van de Water
- Division of Rheumatology/Allergy and Clinical Immunology, Department of Internal Medicine, University of California, Davis, CA, USA
- The M.I.N.D. Institute, University of California, Davis, CA, USA
- NIEHS Center for Children's Environmental Health, University of California, Davis, CA, USA
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15
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Xie Z, Li J, Baker J, Eagleson KL, Coba MP, Levitt P. Receptor Tyrosine Kinase MET Interactome and Neurodevelopmental Disorder Partners at the Developing Synapse. Biol Psychiatry 2016; 80:933-942. [PMID: 27086544 PMCID: PMC5001930 DOI: 10.1016/j.biopsych.2016.02.022] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/10/2015] [Revised: 07/15/2015] [Accepted: 02/15/2016] [Indexed: 12/26/2022]
Abstract
BACKGROUND Atypical synapse development and plasticity are implicated in many neurodevelopmental disorders (NDDs). NDD-associated, high-confidence risk genes have been identified, yet little is known about functional relationships at the level of protein-protein interactions, which are the dominant molecular bases responsible for mediating circuit development. METHODS Proteomics in three independent developing neocortical synaptosomal preparations identified putative interacting proteins of the ligand-activated MET receptor tyrosine kinase, an autism risk gene that mediates synapse development. The candidates were translated into interactome networks and analyzed bioinformatically. Additionally, three independent quantitative proximity ligation assays in cultured neurons and four independent immunoprecipitation analyses of synaptosomes validated protein interactions. RESULTS Approximately 11% (8/72) of MET-interacting proteins, including SHANK3, SYNGAP1, and GRIN2B, are associated with NDDs. Proteins in the MET interactome were translated into a novel MET interactome network based on human protein-protein interaction databases. High-confidence genes from different NDD datasets that encode synaptosomal proteins were analyzed for being enriched in MET interactome proteins. This was found for autism but not schizophrenia, bipolar disorder, major depressive disorder, or attention-deficit/hyperactivity disorder. There is correlated gene expression between MET and its interactive partners in developing human temporal and visual neocortices but not with highly expressed genes that are not in the interactome. Proximity ligation assays and biochemical analyses demonstrate that MET-protein partner interactions are dynamically regulated by receptor activation. CONCLUSIONS The results provide a novel molecular framework for deciphering the functional relations of key regulators of synaptogenesis that contribute to both typical cortical development and to NDDs.
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Affiliation(s)
- Zhihui Xie
- Department of Pediatrics and The Saban Research Institute, Children's Hospital Los Angeles, Los Angeles, California
| | - Jing Li
- Zilkha Neurogenetic Institute, Keck School of Medicine of the University of Southern California, Los Angeles, California
| | - Jonathan Baker
- College of Science, University of Notre Dame, South Bend, Indiana
| | - Kathie L Eagleson
- Department of Pediatrics, Children's Hospital Los Angeles and the Keck School of Medicine of the University of Southern California; Los Angeles, California
| | - Marcelo P Coba
- Zilkha Neurogenetic Institute, Keck School of Medicine of the University of Southern California, Los Angeles, California
| | - Pat Levitt
- Department of Pediatrics, Children's Hospital Los Angeles and the Keck School of Medicine of the University of Southern California; Los Angeles, California; Program in Developmental Neurogenetics, Institute for the Developing Mind and The Saban Research Institute, Children's Hospital Los Angeles, Los Angeles, California.
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16
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Yin J, Schaaf CP. Autism genetics - an overview. Prenat Diagn 2016; 37:14-30. [DOI: 10.1002/pd.4942] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2016] [Revised: 10/04/2016] [Accepted: 10/11/2016] [Indexed: 12/13/2022]
Affiliation(s)
- Jiani Yin
- Department of Molecular and Human Genetics; Baylor College of Medicine; Houston TX USA
- Jan and Dan Duncan Neurological Research Institute at Texas Children's Hospital; Houston TX USA
| | - Christian P. Schaaf
- Department of Molecular and Human Genetics; Baylor College of Medicine; Houston TX USA
- Jan and Dan Duncan Neurological Research Institute at Texas Children's Hospital; Houston TX USA
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17
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Hepatocyte Growth Factor Modulates MET Receptor Tyrosine Kinase and β-Catenin Functional Interactions to Enhance Synapse Formation. eNeuro 2016; 3:eN-NWR-0074-16. [PMID: 27595133 PMCID: PMC5002983 DOI: 10.1523/eneuro.0074-16.2016] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2016] [Revised: 07/19/2016] [Accepted: 07/25/2016] [Indexed: 01/09/2023] Open
Abstract
MET, a pleiotropic receptor tyrosine kinase implicated in autism risk, influences multiple neurodevelopmental processes. There is a knowledge gap, however, in the molecular mechanism through which MET mediates developmental events related to disorder risk. In the neocortex, MET is expressed transiently during periods of peak dendritic outgrowth and synaptogenesis, with expression enriched at developing synapses, consistent with demonstrated roles in dendritic morphogenesis, modulation of spine volume, and excitatory synapse development. In a recent coimmunoprecipitation/mass spectrometry screen, β-catenin was identified as part of the MET interactome in developing neocortical synaptosomes. Here, we investigated the influence of the MET/β-catenin complex in mouse neocortical synaptogenesis. Western blot analysis confirms that MET and β-catenin coimmunoprecipitate, but N-cadherin is not associated with the MET complex. Following stimulation with hepatocyte growth factor (HGF), β-catenin is phosphorylated at tyrosine142 (Y142) and dissociates from MET, accompanied by an increase in β-catenin/N-cadherin and MET/synapsin 1 protein complexes. In neocortical neurons in vitro, proximity ligation assays confirmed the close proximity of these proteins. Moreover, in neurons transfected with synaptophysin-GFP, HGF stimulation increases the density of synaptophysin/bassoon (a presynaptic marker) and synaptophysin/PSD-95 (a postsynaptic marker) clusters. Mutation of β-catenin at Y142 disrupts the dissociation of the MET/β-catenin complex and prevents the increase in clusters in response to HGF. The data demonstrate a new mechanism for the modulation of synapse formation, whereby MET activation induces an alignment of presynaptic and postsynaptic elements that are necessary for assembly and formation of functional synapses by subsets of neocortical neurons that express MET/β-catenin complex.
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18
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Insulin-Independent GABAA Receptor-Mediated Response in the Barrel Cortex of Mice with Impaired Met Activity. J Neurosci 2016; 36:3691-7. [PMID: 27030755 DOI: 10.1523/jneurosci.0006-16.2016] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2016] [Accepted: 02/22/2016] [Indexed: 11/21/2022] Open
Abstract
UNLABELLED Autism spectrum disorder (ASD) is a neurodevelopmental disorder caused by genetic variants, susceptibility alleles, and environmental perturbations. The autism associated geneMETtyrosine kinase has been implicated in many behavioral domains and endophenotypes of autism, including abnormal neural signaling in human sensory cortex. We investigated somatosensory thalamocortical synaptic communication in mice deficient in Met activity in cortical excitatory neurons to gain insights into aberrant somatosensation characteristic of ASD. The ratio of excitation to inhibition is dramatically increased due to decreased postsynaptic GABAAreceptor-mediated inhibition in the trigeminal thalamocortical pathway of mice lacking active Met in the cerebral cortex. Furthermore, in contrast to wild-type mice, insulin failed to increase GABAAreceptor-mediated response in the barrel cortex of mice with compromised Met signaling. Thus, lacking insulin effects may be a risk factor in ASD pathogenesis. SIGNIFICANCE STATEMENT A proposed common cause of neurodevelopmental disorders is an imbalance in excitatory neural transmission, provided by the glutamatergic neurons, and the inhibitory signals from the GABAergic interneurons. Many genes associated with autism spectrum disorders impair synaptic transmission in the expected cell type. Previously, inactivation of the autism-associated Met tyrosine kinase receptor in GABAergic interneurons led to decreased inhibition. In thus report, decreased Met signaling in glutamatergic neurons had no effect on excitation, but decimated inhibition. Further experiments indicate that loss of Met activity downregulates GABAAreceptors on glutamatergic neurons in an insulin independent manner. These data provide a new mechanism for the loss of inhibition and subsequent abnormal excitation/inhibition balance and potential molecular candidates for treatment or prevention.
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19
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Peng Y, Lu Z, Li G, Piechowicz M, Anderson M, Uddin Y, Wu J, Qiu S. The autism-associated MET receptor tyrosine kinase engages early neuronal growth mechanism and controls glutamatergic circuits development in the forebrain. Mol Psychiatry 2016; 21:925-35. [PMID: 26728565 PMCID: PMC4914424 DOI: 10.1038/mp.2015.182] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/27/2015] [Revised: 07/30/2015] [Accepted: 09/08/2015] [Indexed: 12/18/2022]
Abstract
The human MET gene imparts a replicated risk for autism spectrum disorder (ASD), and is implicated in the structural and functional integrity of brain. MET encodes a receptor tyrosine kinase, MET, which has a pleiotropic role in embryogenesis and modifies a large number of neurodevelopmental events. Very little is known, however, on how MET signaling engages distinct cellular events to collectively affect brain development in ASD-relevant disease domains. Here, we show that MET protein expression is dynamically regulated and compartmentalized in developing neurons. MET is heavily expressed in neuronal growth cones at early developmental stages and its activation engages small GTPase Cdc42 to promote neuronal growth, dendritic arborization and spine formation. Genetic ablation of MET signaling in mouse dorsal pallium leads to altered neuronal morphology indicative of early functional maturation. In contrast, prolonged activation of MET represses the formation and functional maturation of glutamatergic synapses. Moreover, manipulating MET signaling levels in vivo in the developing prefrontal projection neurons disrupts the local circuit connectivity made onto these neurons. Therefore, normal time-delimited MET signaling is critical in regulating the timing of neuronal growth, glutamatergic synapse maturation and cortical circuit function. Dysregulated MET signaling may lead to pathological changes in forebrain maturation and connectivity, and thus contribute to the emergence of neurological symptoms associated with ASD.
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Affiliation(s)
- Yun Peng
- Department of Basic Medical Sciences, University of Arizona College of Medicine-Phoenix, Phoenix, AZ 85004
| | - Zhongming Lu
- Department of Basic Medical Sciences, University of Arizona College of Medicine-Phoenix, Phoenix, AZ 85004,Jiangsu Provincial Center for Disease Control and Prevention, Nanjing, China, 210009
| | - Guohui Li
- Department of Basic Medical Sciences, University of Arizona College of Medicine-Phoenix, Phoenix, AZ 85004,Interdisciplinary Graduate Program in Neuroscience, School of Life Science, Arizona State University. Tempe, AZ 85287
| | - Mariel Piechowicz
- Department of Basic Medical Sciences, University of Arizona College of Medicine-Phoenix, Phoenix, AZ 85004
| | - Miranda Anderson
- Department of Basic Medical Sciences, University of Arizona College of Medicine-Phoenix, Phoenix, AZ 85004
| | - Yasin Uddin
- Department of Basic Medical Sciences, University of Arizona College of Medicine-Phoenix, Phoenix, AZ 85004
| | - Jie Wu
- Division of Neurology, Neurological Institute, St. Joseph’s Hospital and Medical Center, Phoenix, AZ 85013
| | - Shenfeng Qiu
- Department of Basic Medical Sciences, University of Arizona College of Medicine-Phoenix, Phoenix, AZ 85004,Interdisciplinary Graduate Program in Neuroscience, School of Life Science, Arizona State University. Tempe, AZ 85287
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20
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Krakowiak P, Walker CK, Tancredi D, Hertz-Picciotto I, Van de Water J. Autism-specific maternal anti-fetal brain autoantibodies are associated with metabolic conditions. Autism Res 2016; 10:89-98. [PMID: 27312731 DOI: 10.1002/aur.1657] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2015] [Revised: 03/18/2016] [Accepted: 05/17/2016] [Indexed: 01/05/2023]
Abstract
Approximately 23% of mothers of children with autism spectrum disorder (ASD) produce specific patterns of autoantibodies to fetal brain proteins that have been detected in only 1% of mothers of typically developing children. The biological mechanisms underlying the development of ASD-specific maternal autoantibodies are poorly understood. We sought to determine whether ASD-specific maternal autoantibodies identified postnatally were associated with metabolic conditions (MCs) during gestation. Participants were 227 mothers of 2-5 year old children with confirmed ASD, enrolled in CHARGE (Childhood Autism Risk from Genetics and the Environment) between January 2003 and April 2008, and from whom blood samples were collected and analyzed for anti-fetal brain autoantibodies (Ab+). MCs included diabetes, hypertensive disorders, and prepregnancy obesity or overweight, ascertained from medical records or structured telephone interviews. Log-linear regression models were performed to estimate prevalence ratios and 95% confidence intervals (CI) based on robust standard errors. Fifty-six (25%) mothers were Ab+. Ab+ prevalence was higher among mothers with diabetes, hypertensive disorders, or overweight compared to healthy mothers, but differences were not statistically significant. In a subset of 145 mothers whose children exhibited severe ASD (31 Ab+), those diagnosed with type 2 or gestational diabetes were 2.7-fold more likely to be Ab+ (95% CI 1.1, 6.6), controlling for delivery payer and smoking. Gestational diabetes specifically was associated with a 3.2-fold increased Ab+ prevalence (95% CI 1.2, 8.6). In this exploratory study, mothers whose children had severe ASD and who experienced diabetes were more likely to have anti-fetal brain autoantibodies 2-5 years later. Autism Res 2017, 10: 89-98. © 2016 International Society for Autism Research, Wiley Periodicals, Inc.
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Affiliation(s)
- Paula Krakowiak
- Divisions of Epidemiology and of Environmental and Occupational Health, Department of Public Health Sciences, School of Medicine, University of California, Davis, California.,Medical Investigations of Neurodevelopmental Disorders Institute (MIND), University of California, Davis, California
| | - Cheryl K Walker
- Medical Investigations of Neurodevelopmental Disorders Institute (MIND), University of California, Davis, California.,Division of Maternal Fetal Medicine, Department of Obstetrics and Gynecology, School of Medicine, University of California, Davis, California
| | - Daniel Tancredi
- Department of Pediatrics, School of Medicine, University of California, Davis, California
| | - Irva Hertz-Picciotto
- Divisions of Epidemiology and of Environmental and Occupational Health, Department of Public Health Sciences, School of Medicine, University of California, Davis, California.,Medical Investigations of Neurodevelopmental Disorders Institute (MIND), University of California, Davis, California
| | - Judy Van de Water
- Medical Investigations of Neurodevelopmental Disorders Institute (MIND), University of California, Davis, California.,Division of Rheumatology, Allergy and Clinical Immunology, Department of Internal Medicine, School of Medicine, University of California, Davis, California
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21
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Tshala-Katumbay D, Mwanza JC, Rohlman DS, Maestre G, Oriá RB. A global perspective on the influence of environmental exposures on the nervous system. Nature 2015; 527:S187-92. [PMID: 26580326 PMCID: PMC4772865 DOI: 10.1038/nature16034] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Economic transitions in the era of globalization warrant a fresh look at the neurological risks associated with environmental change. These are driven by industrial expansion, transfer and mobility of goods, climate change and population growth. In these contexts, risk of infectious and non-infectious diseases are shared across geographical boundaries. In low- and middle-income countries, the risk of environmentally mediated brain disease is augmented several fold by lack of infrastructure, poor health and safety regulations, and limited measures for environmental protection. Neurological disorders may occur as a result of direct exposure to chemical and/or non-chemical stressors, including but not limited to, ultrafine particulate matters. Individual susceptibilities to exposure-related diseases are modified by genetic, epigenetic and metagenomic factors. The existence of several uniquely exposed populations, including those in the areas surrounding the Niger Delta or north western Amazon oil operations; those working in poorly regulated environments, such as artisanal mining industries; or those, mostly in sub-Saharan Africa, relying on cassava as a staple food, offers invaluable opportunities to advance the current understanding of brain responses to environmental challenges. Increased awareness of the brain disorders that are prevalent in low- and middle-income countries and investments in capacity for further environmental health-related research are positive steps towards improving human health.
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Affiliation(s)
- Desire Tshala-Katumbay
- Department of Neurology, Oregon Health &Science University, Portland, Oregon, 97239, USA.,National Institute of Biomedical Research, 1197 Kinshasa I, Congo.,Department of Neurology, University of Kinshasa, 825 Kinshasa XI, Congo
| | - Jean-Claude Mwanza
- Department of Ophthalmology, University of North Carolina at Chapel Hill, North Carolina 27599, USA
| | - Diane S Rohlman
- Occupational and Environmental Health, The University of Iowa, Iowa 52242, USA.,Oregon Institute of Occupational Health Sciences, Oregon Health and Science University, Portland, Oregon, 97239, USA
| | - Gladys Maestre
- G. H. Sergievsky Center, Columbia University Medical Center, New York, New York 10032, USA
| | - Reinaldo B Oriá
- Department of Morphology and Institute of Biomedicine, Faculty of Medicine, Federal University of Ceara, Fortaleza 60020, Brazil
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22
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Pusponegoro HD, Ismael S, Sastroasmoro S, Firmansyah A, Vandenplas Y. Maladaptive Behavior and Gastrointestinal Disorders in Children with Autism Spectrum Disorder. Pediatr Gastroenterol Hepatol Nutr 2015; 18:230-7. [PMID: 26770897 PMCID: PMC4712535 DOI: 10.5223/pghn.2015.18.4.230] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/14/2015] [Revised: 09/06/2015] [Accepted: 09/17/2015] [Indexed: 12/12/2022] Open
Abstract
PURPOSE Various gastrointestinal factors may contribute to maladaptive behavior in children with autism spectrum disorders (ASD). To determine the association between maladaptive behavior in children with ASD and gastrointestinal symptoms such as severity, intestinal microbiota, inflammation, enterocyte damage, permeability and absorption of opioid peptides. METHODS This observational cross-sectional study compared children with ASD to healthy controls, aged 2-10 years. Maladaptive behavior was classified using the Approach Withdrawal Problems Composite subtest of the Pervasive Developmental Disorder Behavior Inventory. Dependent variables were gastrointestinal symptom severity index, fecal calprotectin, urinary D-lactate, urinary lactulose/mannitol excretion, urinary intestinal fatty acids binding protein (I-FABP) and urinary opioid peptide excretion. RESULTS We did not find a significant difference between children with ASD with severe or mild maladaptive behavior and control subjects for gastrointestinal symptoms, fecal calprotectin, urinary D-lactate, and lactulose/mannitol ratio. Urinary opioid peptide excretion was absent in all children. Children with ASD with severe maladaptive behavior showed significantly higher urinary I-FABP levels compared to those with mild maladaptive behavior (p=0.019) and controls (p=0.015). CONCLUSION In our series, maladaptive behavior in ASD children was not associated with gastrointestinal symptoms, intestinal inflammation (no difference in calprotectin), microbiota (no difference in urinary D-lactate) and intestinal permeability (no difference in lactulose/manitol ratio). ASD children with severe maladaptive behavior have significantly more enterocyte damage (increased urinary I-FABP) than ASD children with mild maladaptive behavior and normal children.
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Affiliation(s)
| | - Sofyan Ismael
- Department of Child Health, Medical School, University of Indonesia, Jakarta, Indonesia
| | - Sudigdo Sastroasmoro
- Department of Child Health, Medical School, University of Indonesia, Jakarta, Indonesia
| | - Agus Firmansyah
- Department of Child Health, Medical School, University of Indonesia, Jakarta, Indonesia
| | - Yvan Vandenplas
- Department of Pediatrics, Universitair Ziekenhuis Brussel, Brussels, Belgium
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23
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Thompson BL, Levitt P. Complete or partial reduction of the Met receptor tyrosine kinase in distinct circuits differentially impacts mouse behavior. J Neurodev Disord 2015; 7:35. [PMID: 26523156 PMCID: PMC4628780 DOI: 10.1186/s11689-015-9131-8] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/09/2015] [Accepted: 10/20/2015] [Indexed: 12/23/2022] Open
Abstract
BACKGROUND Our laboratory discovered that the gene encoding the receptor tyrosine kinase, MET, contributes to autism risk. Expression of MET is reduced in human postmortem temporal lobe in autism and Rett Syndrome. Subsequent studies revealed a role for MET in human and mouse functional and structural cortical connectivity. To further understand the contribution of Met to brain development and its impact on behavior, we generated two conditional mouse lines in which Met is deleted from select populations of central nervous system neurons. Mice were then tested to determine the consequences of disrupting Met expression. METHODS Mating of Emx1 (cre) and Met (fx/fx) mice eliminates receptor signaling from all cells arising from the dorsal pallium. Met (fx/fx) and Nestin (cre) crosses result in receptor signaling elimination from all neural cells. Behavioral tests were performed to assess cognitive, emotional, and social impairments that are observed in multiple neurodevelopmental disorders and that are in part subserved by circuits that express Met. RESULTS Met (fx/fx) /Emx1 (cre) null mice displayed significant hypoactivity in the activity chamber and in the T-maze despite superior performance on the rotarod. Additionally, these animals showed a deficit in spontaneous alternation. Surprisingly, Met (fx/fx; fx/+) /Nestin (cre) null and heterozygous mice exhibited deficits in contextual fear conditioning, and Met (fx/+) /Nestin (cre) heterozygous mice spent less time in the closed arms of the elevated plus maze. CONCLUSIONS These data suggest a complex contribution of Met in the development of circuits mediating social, emotional, and cognitive behavior. The impact of disrupting developmental Met expression is dependent upon circuit-specific deletion patterns and levels of receptor activity.
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Affiliation(s)
- Barbara L Thompson
- Chan Division of Occupational Science and Occupational Therapy, Herman Ostrow School of Dentistry, University of Southern California, Los Angeles, CA 90089 USA ; Institute for the Developing Mind, Children's Hospital of Los Angeles, Keck School of Medicine, University of Southern California, Los Angeles, CA 90027 USA ; Department of Pediatrics, Children's Hospital of Los Angeles, Keck School of Medicine, University of Southern California, Los Angeles, CA 90027 USA
| | - Pat Levitt
- Institute for the Developing Mind, Children's Hospital of Los Angeles, Keck School of Medicine, University of Southern California, Los Angeles, CA 90027 USA ; Department of Pediatrics, Children's Hospital of Los Angeles, Keck School of Medicine, University of Southern California, Los Angeles, CA 90027 USA
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24
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Immune mediators in the brain and peripheral tissues in autism spectrum disorder. Nat Rev Neurosci 2015; 16:469-86. [PMID: 26189694 DOI: 10.1038/nrn3978] [Citation(s) in RCA: 328] [Impact Index Per Article: 36.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Increasing evidence points to a central role for immune dysregulation in autism spectrum disorder (ASD). Several ASD risk genes encode components of the immune system and many maternal immune system-related risk factors--including autoimmunity, infection and fetal reactive antibodies--are associated with ASD. In addition, there is evidence of ongoing immune dysregulation in individuals with ASD and in animal models of this disorder. Recently, several molecular signalling pathways--including pathways downstream of cytokines, the receptor MET, major histocompatibility complex class I molecules, microglia and complement factors--have been identified that link immune activation to ASD phenotypes. Together, these findings indicate that the immune system is a point of convergence for multiple ASD-related genetic and environmental risk factors.
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Bresnahan M, Hornig M, Schultz AF, Gunnes N, Hirtz D, Lie KK, Magnus P, Reichborn-Kjennerud T, Roth C, Schjølberg S, Stoltenberg C, Surén P, Susser E, Lipkin WI. Association of maternal report of infant and toddler gastrointestinal symptoms with autism: evidence from a prospective birth cohort. JAMA Psychiatry 2015; 72:466-74. [PMID: 25806498 PMCID: PMC4939710 DOI: 10.1001/jamapsychiatry.2014.3034] [Citation(s) in RCA: 91] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
IMPORTANCE Gastrointestinal (GI) comorbidities are frequently described in association with autism spectrum disorder (ASD). However, the prevalence of GI disturbances and the age at which such problems first appear are unclear, and their specificity for ASD compared with other neurodevelopmental disorders is uncertain. OBJECTIVE To compare maternal report of GI symptoms during the first 3 years of life in children with ASD, developmental delay (DD), and typical development (TD). DESIGN, SETTING, AND PARTICIPANTS This large prospective cohort study consists of participants in the Norwegian Mother and Child Cohort Study. During a 10-year period (January 1, 1999, through December 31, 2008), women throughout Norway were recruited at the first prenatal ultrasonographic visit (approximately 18 weeks' gestation). The study enrolled 95,278 mothers, 75,248 fathers, and 114,516 children. Our analyses are based on MoBa data released through October 1, 2013, and NPR diagnoses registered through December 31, 2012, and include children born from January 1, 2002, through December 31, 2008, with completed age 18- and 36-month questionnaires. EXPOSURES We defined 3 groups of children: children with ASD (n = 195), children with DD and delayed language and/or motor development (n = 4636), and children with TD (n = 40 ,95). MAIN OUTCOMES AND MEASURES The GI symptoms were based on maternal report of constipation, diarrhea, and food allergy/intolerance. RESULTS Children with ASD were at significantly increased odds of maternally reported constipation (adjusted odds ratio [aOR], 2.7; 95% CI, 1.9-3.8; P < .001) and food allergy/intolerance (aOR, 1.7; 95% CI, 1.1-2.6; P = .01) in the 6- to 18-month-old age period and diarrhea (aOR, 2.3; 95% CI, 1.5-3.6; P < .001), constipation (aOR, 1.6; 95% CI, 1.2-2.3; P < .01), and food allergy/intolerance (aOR, 2.0; 95% CI, 1.3-3.1; P < .01) in the 18- to 36-month-old age period compared with children with TD. Similar results for these symptom categories were observed in comparisons with children with DD, but ORs were slightly lower. Mothers of children with ASD were significantly more likely to report 1 or more GI symptom in either the 6- to 18-month or the 18- to 36-month-old age period and more than twice as likely to report at least 1 GI symptom in both age periods compared with mothers of children with TD or DD. CONCLUSIONS AND RELEVANCE In this large prospective cohort, maternally reported GI symptoms are more common and more often persistent during the first 3 years of life in children with ASD than in children with TD or DD.
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Affiliation(s)
- Michaeline Bresnahan
- Department of Epidemiology, Mailman School of Public Health, Columbia University, New York, New York2New York State Psychiatric Institute, New York
| | - Mady Hornig
- Department of Epidemiology, Mailman School of Public Health, Columbia University, New York, New York3The Center for Infection and Immunity, Mailman School of Public Health, Columbia University, New York, New York
| | - Andrew F. Schultz
- The Center for Infection and Immunity, Mailman School of Public Health, Columbia University, New York, New York
| | - Nina Gunnes
- Norwegian Institute of Public Health, Oslo, Norway
| | - Deborah Hirtz
- National Institute of Neurological Disorders and Stroke, Bethesda, Maryland
| | | | - Per Magnus
- Norwegian Institute of Public Health, Oslo, Norway
| | - Ted Reichborn-Kjennerud
- Norwegian Institute of Public Health, Oslo, Norway6Institute of Clinical Medicine, Faculty of Medicine, University of Oslo, Oslo, Norway
| | - Christine Roth
- Department of Epidemiology, Mailman School of Public Health, Columbia University, New York, New York4Norwegian Institute of Public Health, Oslo, Norway
| | | | | | - Pål Surén
- Norwegian Institute of Public Health, Oslo, Norway
| | - Ezra Susser
- Department of Epidemiology, Mailman School of Public Health, Columbia University, New York, New York2New York State Psychiatric Institute, New York
| | - W. Ian Lipkin
- Department of Epidemiology, Mailman School of Public Health, Columbia University, New York, New York3The Center for Infection and Immunity, Mailman School of Public Health, Columbia University, New York, New York
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MET receptor tyrosine kinase controls dendritic complexity, spine morphogenesis, and glutamatergic synapse maturation in the hippocampus. J Neurosci 2015; 34:16166-79. [PMID: 25471559 DOI: 10.1523/jneurosci.2580-14.2014] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
The MET receptor tyrosine kinase (RTK), implicated in risk for autism spectrum disorder (ASD) and in functional and structural circuit integrity in humans, is a temporally and spatially regulated receptor enriched in dorsal pallial-derived structures during mouse forebrain development. Here we report that loss or gain of function of MET in vitro or in vivo leads to changes, opposite in nature, in dendritic complexity, spine morphogenesis, and the timing of glutamatergic synapse maturation onto hippocampus CA1 neurons. Consistent with the morphological and biochemical changes, deletion of Met in mutant mice results in precocious maturation of excitatory synapse, as indicated by a reduction of the proportion of silent synapses, a faster GluN2A subunit switch, and an enhanced acquisition of AMPA receptors at synaptic sites. Thus, MET-mediated signaling appears to serve as a mechanism for controlling the timing of neuronal growth and functional maturation. These studies suggest that mistimed maturation of glutamatergic synapses leads to the aberrant neural circuits that may be associated with ASD risk.
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Lambert N, Wermenbol V, Pichon B, Acosta S, van den Ameele J, Perazzolo C, Messina D, Musumeci MF, Dessars B, De Leener A, Abramowicz M, Vilain C. A familial heterozygous null mutation of MET in autism spectrum disorder. Autism Res 2014; 7:617-22. [PMID: 24909855 DOI: 10.1002/aur.1396] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2013] [Accepted: 05/01/2014] [Indexed: 12/26/2022]
Abstract
Autism spectrum disorder (ASD) results from interactions of genetic and environmental factors. The MET proto-oncogene has been identified as a candidate gene for autism susceptibility, and is implicated in neurodevelopment and social brain circuitry. Here, we describe the first case of a familial mutation of MET, consisting of an interstitial genomic deletion removing exons 12 through 15, causing a frameshift and premature stop codon, with evidence of nonsense-mediated mRNA decay. On the other allele, patients carried the C allele of the MET promoter rs1858830 polymorphism, known to decrease MET expression and previously associated with autism susceptibility. The heterozygous mutation was associated with autism in one patient, and language and social impairment in a sibling. Our observations delineate the phenotypic spectrum associated with a clearly defined, very likely complete loss of function mutation of MET. Incomplete penetrance in this family was consistent with MET as a partial susceptibility gene for ASD. Implication of MET in normal and pathological brain development opens new perspectives for understanding the pathophysiology of autism and for eventual therapeutical clues.
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Affiliation(s)
- Nelle Lambert
- ULB Center of Human Genetics, Hôpital Erasme, Université Libre de Bruxelles (ULB), Brussels, Belgium; Institut de Recherche Interdisciplinaire en Biologie Humaine et Moléculaire (IRIBHM), Université Libre de Bruxelles (ULB), Route de Lennik 808, 1070, Brussels, Belgium
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A translational neuroscience framework for the development of socioemotional functioning in health and psychopathology. Dev Psychopathol 2013; 25:1293-309. [DOI: 10.1017/s095457941300062x] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
AbstractThe development of socioemotional functioning is a complex process that occurs over a protracted time period and requires coordinating affective, cognitive, and social faculties. At many points in development, the trajectory of socioemotional development can be deleteriously altered due to a combination of environmental insults and individual vulnerabilities. The result can be psychopathology. However, researchers are just beginning to understand the neural and genetic mechanisms involved in the development of healthy and disordered socioemotional functioning. We propose a translational developmental neuroscience framework to understand the transactional process that results in socioemotional functioning in both healthy and disordered populations. We then apply this framework to healthy socioemotional development, pediatric anxiety, pediatric depression, and autism spectrum disorder, selectively reviewing current literature in light of the framework. Finally, we examine ways that the framework can help to frame future directions of research on socioemotional development and translational implications for intervention.
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Plummer JT, Evgrafov OV, Bergman MY, Friez M, Haiman CA, Levitt P, Aldinger KA. Transcriptional regulation of the MET receptor tyrosine kinase gene by MeCP2 and sex-specific expression in autism and Rett syndrome. Transl Psychiatry 2013; 3:e316. [PMID: 24150225 PMCID: PMC3818007 DOI: 10.1038/tp.2013.91] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/26/2013] [Revised: 09/04/2013] [Accepted: 09/08/2013] [Indexed: 12/11/2022] Open
Abstract
Single nucleotide variants (SNV) in the gene encoding the MET receptor tyrosine kinase have been associated with an increased risk for autism spectrum disorders (ASD). The MET promoter SNV rs1858830 C 'low activity' allele is enriched in ASD, associated with reduced protein expression, and impacts functional and structural circuit connectivity in humans. To gain insight into the transcriptional regulation of MET on ASD-risk etiology, we examined an interaction between the methyl CpG-binding protein 2 (MeCP2) and the MET 5' promoter region. Mutations in MeCP2 cause Rett syndrome (RTT), a predominantly female neurodevelopmental disorder sharing some ASD clinical symptoms. MeCP2 binds to a region of the MET promoter containing the ASD-risk SNV, and displays rs1858830 genotype-specific binding in human neural progenitor cells derived from the olfactory neuroepithelium. MeCP2 binding enhances MET expression in the presence of the rs1858830 C allele, but MET transcription is attenuated by RTT-specific mutations in MeCP2. In the postmortem temporal cortex, a region normally enriched in MET, gene expression is reduced dramatically in females with RTT, although not due to enrichment of the rs1858830 C 'low activity' allele. We newly identified a sex-based reduction in MET expression, with male ASD cases, but not female ASD cases compared with sex-matched controls. The experimental data reveal a prominent allele-specific regulation of MET transcription by MeCP2. The mechanisms underlying the pronounced reduction of MET in ASD and RTT temporal cortex are distinct and likely related to factors unique to each disorder, including a noted sex bias.
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Affiliation(s)
- J T Plummer
- Zilkha Neurogenetic Institute, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA
| | - O V Evgrafov
- Zilkha Neurogenetic Institute, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA,Department of Psychiatry and Behavioral Sciences, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA
| | - M Y Bergman
- Vanderbilt University School of Medicine, Nashville, TN, USA
| | - M Friez
- Greenwood Genetic Center, Greenwood, SC, USA
| | - C A Haiman
- Department of Preventive Medicine, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA
| | - P Levitt
- Zilkha Neurogenetic Institute, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA,Department of Cell & Neurobiology, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA
| | - K A Aldinger
- Zilkha Neurogenetic Institute, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA,Center for Integrative Brain Research, Seattle Children's Research Institute, 1900 9th Avenue, Seattle, 98101 WA, USA. E-mail:
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Russo AJ. Correlation Between Hepatocyte Growth Factor (HGF) and Gamma-Aminobutyric Acid (GABA) Plasma Levels in Autistic Children. Biomark Insights 2013; 8:69-75. [PMID: 23825437 PMCID: PMC3694825 DOI: 10.4137/bmi.s11448] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
There is much support for the role of Gamma-Aminobutyric acid (GABA) in the etiology of autism. Recent research has shown that hepatocyte growth factor (HGF) modulates GABAergic inhibition and seizure susceptibility. This study was designed to determine and correlate plasma levels of HGF, GABA, as well as symptom severity, in autistic children and neurotypical controls. Plasma from 48 autistic children and 29 neurotypical controls was assessed for HGF and GABA concentration using ELISAs. Symptom severity was assessed in these autistic individuals and compared to HGF and GABA concentrations. We previously reported that autistic children had significantly decreased levels of HGF. In this study, the same autistic children had significantly increased plasma levels of GABA (P = 0.002) and decreased HGF levels correlated with these increased GABA levels (r = 0.3; P = 0.05). High GABA levels correlated with increasing hyperactivity (r = 0.6; P = 0.0007) and impulsivity severity (r = 0.5; P = 0.007), tip toeing severity (r = 0.35; P = 0.03), light sensitivity (r = 0.4; P = 0.02), and tactile sensitivity (r = 0.4; P = 0.01). HGF levels did not correlate significantly with any symptom severity. These results suggest an association between HGF and GABA levels and suggest that plasma GABA levels are related to symptom severity in autistic children.
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Affiliation(s)
- Anthony J Russo
- Visiting Assistant Professor of Biology, Hartwick College, Oneonta, NY, USA
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31
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Murdoch JD, State MW. Recent developments in the genetics of autism spectrum disorders. Curr Opin Genet Dev 2013; 23:310-5. [DOI: 10.1016/j.gde.2013.02.003] [Citation(s) in RCA: 102] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2012] [Revised: 01/30/2013] [Accepted: 02/05/2013] [Indexed: 12/25/2022]
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Wu HH, Levitt P. Prenatal expression of MET receptor tyrosine kinase in the fetal mouse dorsal raphe nuclei and the visceral motor/sensory brainstem. Dev Neurosci 2013; 35:1-16. [PMID: 23548689 DOI: 10.1159/000346367] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2012] [Accepted: 12/04/2012] [Indexed: 12/15/2022] Open
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.
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Affiliation(s)
- Hsiao-Huei Wu
- Department of Cell and Neurobiology, Zilkha Neurogenetic Institute, Keck School of Medicine of the University of Southern California, Los Angeles, Calif. 90089, USA
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Peng Y, Huentelman M, Smith C, Qiu S. MET receptor tyrosine kinase as an autism genetic risk factor. INTERNATIONAL REVIEW OF NEUROBIOLOGY 2013; 113:135-65. [PMID: 24290385 DOI: 10.1016/b978-0-12-418700-9.00005-8] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
In this chapter, we will briefly discuss recent literature on the role of MET receptor tyrosine kinase (RTK) in brain development and how perturbation of MET signaling may alter normal neurodevelopmental outcomes. Recent human genetic studies have established MET as a risk factor for autism, and the molecular and cellular underpinnings of this genetic risk are only beginning to emerge from obscurity. Unlike many autism risk genes that encode synaptic proteins, the spatial and temporal expression pattern of MET RTK indicates this signaling system is ideally situated to regulate neuronal growth, functional maturation, and establishment of functional brain circuits, particularly in those brain structures involved in higher levels of cognition, social skills, and executive functions.
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Affiliation(s)
- Yun Peng
- Department of Basic Medical Sciences, University of Arizona College of Medicine, Phoenix, Arizona, USA
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Rudie JD, Hernandez LM, Brown JA, Beck-Pancer D, Colich NL, Gorrindo P, Thompson PM, Geschwind DH, Bookheimer SY, Levitt P, Dapretto M. Autism-associated promoter variant in MET impacts functional and structural brain networks. Neuron 2012; 75:904-15. [PMID: 22958829 DOI: 10.1016/j.neuron.2012.07.010] [Citation(s) in RCA: 115] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/05/2012] [Indexed: 11/18/2022]
Abstract
As genes that confer increased risk for autism spectrum disorder (ASD) are identified, a crucial next step is to determine how these risk factors impact brain structure and function and contribute to disorder heterogeneity. With three converging lines of evidence, we show that a common, functional ASD risk variant in the Met Receptor Tyrosine Kinase (MET) gene is a potent modulator of key social brain circuitry in children and adolescents with and without ASD. MET risk genotype predicted atypical fMRI activation and deactivation patterns to social stimuli (i.e., emotional faces), as well as reduced functional and structural connectivity in temporo-parietal regions known to have high MET expression, particularly within the default mode network. Notably, these effects were more pronounced in individuals with ASD. These findings highlight how genetic stratification may reduce heterogeneity and help elucidate the biological basis of complex neuropsychiatric disorders such as ASD.
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Affiliation(s)
- Jeffrey D Rudie
- Ahmanson-Lovelace Brain Mapping Center, University of California, Los Angeles, Los Angeles, CA 90095-7085, USA
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Hedrick A, Lee Y, Wallace GL, Greenstein D, Clasen L, Giedd JN, Raznahan A. Autism risk gene MET variation and cortical thickness in typically developing children and adolescents. Autism Res 2012; 5:434-9. [PMID: 23097380 DOI: 10.1002/aur.1256] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2012] [Accepted: 09/05/2012] [Indexed: 12/15/2022]
Abstract
MET receptor tyrosine kinase (MET) has been proposed as a candidate risk gene for autism spectrum disorder (ASD) based on associations between MET polymorphisms and ASD diagnosis, as well as evidence from animal studies that MET protein may regulate early development of cortical regions implicated in the neurobiology of ASD. The relevance of differences in MET signaling for human cortical development remains unexamined, however. We sought to address this issue by relating genotype at a functional single nucleotide polymorphism within the MET promoter (rs1858830, G→C) to in vivo measures of cortical thickness (CT) development derived from 222 healthy children and adolescents with 514 longitudinally acquired structural magnetic resonance imaging brain scans between ages 9 and 22 years. We identified a statistically significant, developmentally fixed, and stepwise CT reduction with increasing C allele dose in superior and middle temporal gyri, ventral precentral and postcentral gyri, and anterior cingulate bilaterally, and in the right frontopolar cortex. We were also able to demonstrate that mean CT within these cortical regions showed a statistically significant reduction with increasing scores on a continuous measure of autistic traits (the Social Responsiveness Scale). The cortical regions highlighted by our analyses are not only established areas of MET expression during prenatal life but are also key components of the "social brain" that have frequently shown structural and functional abnormalities in autism. Our results suggest that genetic differences in the MET gene may influence the development of cortical systems implicated in the neurobiology of ASD.
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Affiliation(s)
- Alexis Hedrick
- Child Psychiatry Branch, National Institute of Mental Health, Bethesda, MD 20814, USA
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36
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Li X, Zou H, Brown WT. Genes associated with autism spectrum disorder. Brain Res Bull 2012; 88:543-52. [PMID: 22688012 DOI: 10.1016/j.brainresbull.2012.05.017] [Citation(s) in RCA: 64] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2012] [Accepted: 05/31/2012] [Indexed: 01/06/2023]
Abstract
Autism spectrum disorder (ASD) is a heterogeneous grouping of neurodevelopmental disorders characterized by impairment in social interaction, verbal communication and repetitive/stereotypic behaviors. Much evidence suggests that ASD is multifactorial with a strong genetic basis, but the underlying mechanisms are far from clear. Recent advances in genetic technologies are beginning to shed light on possible etiologies of ASD. This review discusses current evidence for several widely studied candidate ASD genes, as well as various rare genes that supports their relationship to the etiology of ASD. The majority of the data are based on molecular, cytogenetic, linkage and association studies of autistic subjects, but newer methods, including whole-exome sequencing, are also beginning to make significant contributions to our understanding of autism.
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Affiliation(s)
- Xiaohong Li
- Department of Neurochemistry, New York State Institute for Basic Research in Developmental Disabilities, New York, NY 10314, United States.
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Abstract
As epidemiologic studies continue to note a striking increase in rates of autism spectrum disorder (ASD) diagnosis around the world, the lack of identified causative agents in most cases remains a major hindrance to the development of treatment and prevention strategies. Published observations of immune system abnormalities in ASD have increased recently, with several groups identifying fetal protein reactive IgG antibodies in plasma from mothers of children with autism. Furthermore, other gestational immune parameters, including maternal infection and dysregulated cytokine signaling, have been found to be associated with ASD in some cases. While detailed pathogenic mechanisms remain to be determined, the hypothesis that some cases of ASD may be influenced, or even caused, by maternal fetal brain-reactive antibodies or other in utero immune-related exposures is an active area of investigation. This article reviews the current literature in this area and proposes several directions for future research.
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38
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Qiu S, Aldinger KA, Levitt P. Modeling of autism genetic variations in mice: focusing on synaptic and microcircuit dysfunctions. Dev Neurosci 2012; 34:88-100. [PMID: 22572629 DOI: 10.1159/000336644] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2011] [Accepted: 12/21/2011] [Indexed: 12/24/2022] Open
Abstract
Autism spectrum disorders (ASD) are heterogeneous neurodevelopmental disorders that are characterized by deficits in social interaction, verbal and nonverbal communication, and restrictive interests and repetitive behaviors. While human genetic studies have revealed marked heritability in ASD, it has been challenging to translate this genetic risk into a biological mechanism that influences brain development relevant to the disorder phenotypes. This is partly due to the complex genetic architecture of ASD, which involves de novo gene mutations, genomic abnormalities, and common genetic variants. Rather than trying to reconstitute the clinical disorder, using genetic model animals to examine specific features of core ASD pathophysiology offers unique opportunities for refining our understanding of neurodevelopmental mechanisms in ASD. A variety of ASD-relevant phenotypes can now be investigated in rodents, including stereotyped and repetitive behaviors, and deficits in social interaction and communication. In this review, we focus on several prevailing mouse models and discuss how studies have advanced our understanding of synaptic mechanisms that may underlie ASD pathophysiology. Although synaptic perturbations are not the only alterations relevant for ASD, we reason that understanding the synaptic underpinnings of ASD using mouse models may provide mechanistic insights into its etiology and lead to novel therapeutic and interventional strategies.
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Affiliation(s)
- Shenfeng Qiu
- Department of Cell and Neurobiology, Zilkha Neurogenetic Institute, Keck School of Medicine, University of Southern California, Los Angeles, Calif., USA
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Shepherd GMG, Katz DM. Synaptic microcircuit dysfunction in genetic models of neurodevelopmental disorders: focus on Mecp2 and Met. Curr Opin Neurobiol 2011; 21:827-33. [PMID: 21733672 PMCID: PMC3199024 DOI: 10.1016/j.conb.2011.06.006] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2011] [Revised: 06/08/2011] [Accepted: 06/09/2011] [Indexed: 12/20/2022]
Abstract
Recent findings in the genetics of neurodevelopmental syndromes have ushered in an exciting era of discovery in which substrates of neurologic dysfunction are being identified at the synaptic and microcircuit levels in mouse models of these disorders. We review recent progress in this area, focusing on two examples of mouse models of autism spectrum disorders (ASDs): Mecp2 models of Rett syndrome, and a Met-knockout model of non-syndromic forms of autism. In both cases, a dominant theme is changes in synaptic strength, associated with hyper-connectivity or hypo-connectivity in specific microcircuits. Alterations in intrinsic neuronal excitability are also found, but do not appear to be as common. The microcircuit-specific nature of synaptic changes observed in these ASD models indicates that it will be necessary to define mechanisms of circuit dysfunction on a case-by-case basis, not only in neocortex but also in brainstem and other sub-cortical areas. Thus, functional microcircuit analysis is emerging as an important line of investigation, highly complementary to neurogenetic and molecular strategies, and holds promise for generating models of the underlying pathophysiology and for guiding development of novel therapeutic strategies.
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Affiliation(s)
- Gordon M G Shepherd
- Department of Physiology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
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Zhou X, Xu Y, Wang J, Zhou H, Liu X, Ayub Q, Wang X, Tyler-Smith C, Wu L, Xue Y. Replication of the association of a MET variant with autism in a Chinese Han population. PLoS One 2011; 6:e27428. [PMID: 22110649 PMCID: PMC3217055 DOI: 10.1371/journal.pone.0027428] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2010] [Accepted: 10/16/2011] [Indexed: 12/27/2022] Open
Abstract
BACKGROUND Autism is a common, severe and highly heritable neurodevelopmental disorder in children, affecting up to 100 children per 10,000. The MET gene has been regarded as a promising candidate gene for this disorder because it is located within a replicated linkage interval, is involved in pathways affecting the development of the cerebral cortex and cerebellum in ways relevant to autism patients, and has shown significant association signals in previous studies. PRINCIPAL FINDINGS Here, we present new ASD patient and control samples from Heilongjiang, China and use them in a case-control and family-based replication study of two MET variants. One SNP, rs38845, was successfully replicated in a case-control association study, but failed to replicate in a family-based study, possibly due to small sample size. The other SNP, rs1858830, failed to replicate in both case-control and family-based studies. CONCLUSIONS This is the first attempt to replicate associations in Chinese autism samples, and our result provides evidence that MET variants may be relevant to autism susceptibility in the Chinese Han population.
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Affiliation(s)
- Xue Zhou
- Department of Children's and Adolescent Health, Public Health College of Harbin Medical University, Harbin, Heilongjiang, People's Republic of China
- The Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridgeshire, United Kingdom
| | - Yang Xu
- Department of Children's and Adolescent Health, Public Health College of Harbin Medical University, Harbin, Heilongjiang, People's Republic of China
| | - Jia Wang
- Department of Children's and Adolescent Health, Public Health College of Harbin Medical University, Harbin, Heilongjiang, People's Republic of China
| | - Hongbo Zhou
- The Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridgeshire, United Kingdom
- Department of Biochemistry and Molecular Biology, Basic Medical Science College of Harbin Medical University, Harbin, Heilongjiang, People's Republic of China
| | - Xian Liu
- Department of Children's and Adolescent Health, Public Health College of Harbin Medical University, Harbin, Heilongjiang, People's Republic of China
| | - Qasim Ayub
- The Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridgeshire, United Kingdom
| | - Xuelai Wang
- Department of Children's and Adolescent Health, Public Health College of Harbin Medical University, Harbin, Heilongjiang, People's Republic of China
| | - Chris Tyler-Smith
- The Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridgeshire, United Kingdom
| | - Lijie Wu
- Department of Children's and Adolescent Health, Public Health College of Harbin Medical University, Harbin, Heilongjiang, People's Republic of China
| | - Yali Xue
- The Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridgeshire, United Kingdom
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41
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Abstract
Recent advances in the genetics of autism spectrum disorders (ASDs) are offering new valuable insights into molecular and cellular mechanisms of pathology. At the same time, the emerging data challenge long-standing diagnostic conventions and the notion of phenotypic specificity. This review addresses the particular issues that attend gene discovery in neuropsychiatric and neurodevelopmental disorders and ASDs in particular, summarizes recent findings in human genetics broadly that are driving the reevaluation of the conventional wisdom regarding the allelic architecture of common psychiatric conditions, reviews selected discoveries in ASDs and their relevance to models of pathology, highlights the conceptual and practical issues raised by the observation of a convergence of ASD genetic risks with distinct psychiatric disorders, and considers the important interplay of studies of neurobiology and genetics in clarifying and extending our understanding of social disability syndromes.
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42
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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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43
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Heuer L, Braunschweig D, Ashwood P, Van de Water J, Campbell DB. Association of a MET genetic variant with autism-associated maternal autoantibodies to fetal brain proteins and cytokine expression. Transl Psychiatry 2011; 1:e48. [PMID: 22833194 PMCID: PMC3309488 DOI: 10.1038/tp.2011.48] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
The contribution of peripheral immunity to autism spectrum disorders (ASDs) risk is debated and poorly understood. Some mothers of children with ASD have autoantibodies that react to fetal brain proteins, raising the possibility that a subset of ASD cases may be associated with a maternal antibody response during gestation. The mechanism by which the maternal immune system breaks tolerance has not been addressed. We hypothesized that the mechanism may involve decreased expression of the MET receptor tyrosine kinase, an ASD risk gene that also serves as a key negative regulator of immune responsiveness. In a sample of 365 mothers, including 202 mothers of children with ASD, the functional MET promoter variant rs1858830 C allele was strongly associated with the presence of an ASD-specific 37+73-kDa band pattern of maternal autoantibodies to fetal brain proteins (P=0.003). To determine the mechanism of this genetic association, we measured MET protein and cytokine production in freshly prepared peripheral blood mononuclear cells from 76 mothers of ASD and typically developing children. The MET rs1858830 C allele was significantly associated with MET protein expression (P=0.025). Moreover, decreased expression of the regulatory cytokine IL-10 was associated with both the MET gene C allele (P=0.001) and reduced MET protein levels (P=0.002). These results indicate genetic distinction among mothers who produce ASD-associated antibodies to fetal brain proteins, and suggest a potential mechanism for how a genetically determined decrease in MET protein production may lead to a reduction in immune regulation.
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Affiliation(s)
- L Heuer
- Department of Internal Medicine, University of California, Davis, Davis, CA, USA,University of California, Davis M.I.N.D. Institute, Davis, CA, USA
| | - D Braunschweig
- Department of Internal Medicine, University of California, Davis, Davis, CA, USA,University of California, Davis M.I.N.D. Institute, Davis, CA, USA
| | - P Ashwood
- University of California, Davis M.I.N.D. Institute, Davis, CA, USA,Department of Medical Microbiology, University of California, Davis, Davis, CA, USA
| | - J Van de Water
- Department of Internal Medicine, University of California, Davis, Davis, CA, USA,University of California, Davis M.I.N.D. Institute, Davis, CA, USA,Division of Rheumatology/Allergy and Clinical Immunology; 451 E. Health Sciences Dr., Suite 6510; University of California Davis; Davis, CA 95616, USA. E-mail:
| | - D B Campbell
- Department of Psychiatry and the Behavioral Sciences, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA,Zilkha Neurogenetic Institute, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA,213 Zilkha Neurogenetic Institute, Keck School of Medicine, University of Southern California, Los Angeles, CA 90089, USA. E-mail:
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44
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Genetics and function of neocortical GABAergic interneurons in neurodevelopmental disorders. Neural Plast 2011; 2011:649325. [PMID: 21876820 PMCID: PMC3159129 DOI: 10.1155/2011/649325] [Citation(s) in RCA: 117] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2011] [Accepted: 05/04/2011] [Indexed: 12/04/2022] Open
Abstract
A dysfunction of cortical and limbic GABAergic circuits has been postulated to contribute to multiple neurodevelopmental disorders in humans, including schizophrenia, autism, and epilepsy. In the current paper, I summarize the characteristics that underlie the great diversity of cortical GABAergic interneurons and explore how the multiple roles of these cells in developing and mature circuits might contribute to the aforementioned disorders. Furthermore, I review the tightly controlled genetic cascades that determine the fate of cortical interneurons and summarize how the dysfunction of genes important for the generation, specification, maturation, and function of cortical interneurons might contribute to these disorders.
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45
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A new synaptic player leading to autism risk: Met receptor tyrosine kinase. J Neurodev Disord 2011; 3:282-92. [PMID: 21509596 PMCID: PMC3261279 DOI: 10.1007/s11689-011-9081-8] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/10/2011] [Accepted: 03/25/2011] [Indexed: 12/14/2022] Open
Abstract
The validity for assigning disorder risk to an autism spectrum disorder (ASD) candidate gene comes from convergent genetic, clinical, and developmental neurobiology data. Here, we review these lines of evidence from multiple human genetic studies, and non-human primate and mouse experiments that support the conclusion that the MET receptor tyrosine kinase (RTK) functions to influence synapse development in circuits relevant to certain core behavioral domains of ASD. There is association of both common functional alleles and rare copy number variants that impact levels of MET expression in the human cortex. The timing of Met expression is linked to axon terminal outgrowth and synaptogenesis in the developing rodent and primate forebrain, and both in vitro and in vivo studies implicate this RTK in dendritic branching, spine maturation, and excitatory connectivity in the neocortex. This impact can occur in a cell-nonautonomous fashion, emphasizing the unique role that Met plays in specific circuits relevant to ASD.
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46
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Qiu S, Anderson CT, Levitt P, Shepherd GMG. Circuit-specific intracortical hyperconnectivity in mice with deletion of the autism-associated Met receptor tyrosine kinase. J Neurosci 2011; 31:5855-64. [PMID: 21490227 PMCID: PMC3086026 DOI: 10.1523/jneurosci.6569-10.2011] [Citation(s) in RCA: 92] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2010] [Revised: 02/04/2011] [Accepted: 02/17/2011] [Indexed: 01/04/2023] Open
Abstract
Local hyperconnectivity in the neocortex is a hypothesized pathophysiological state in autism spectrum disorder (ASD). MET, a receptor tyrosine kinase that regulates dendrite and spine morphogenesis, has been established as a risk gene for ASD. Here, we analyzed the synaptic circuit organization of identified pyramidal neurons in the anterior frontal cortex of mice with a dorsal pallium-derived, conditional knock-out (cKO) of Met. Synaptic mapping by glutamate uncaging identified layer 2/3 as the main source of local excitatory input to layer 5 projection neurons in controls. In both cKO and heterozygotes, this pathway was stronger by a factor of approximately 2. This increase was both sublayer and projection-class specific, restricted to corticostriatal neurons in upper layer 5B and not neighboring corticopontine neurons. Paired recordings in cKO slices demonstrated increased unitary connectivity. We propose that excitatory hyperconnectivity in specific neocortical microcircuits constitutes a physiological basis for Met-mediated ASD risk.
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Affiliation(s)
- Shenfeng Qiu
- Zilkha Neurogenetics Institute, Department of Cell and Neurobiology, Keck School of Medicine, University of Southern California, Los Angeles, California 90089, and
| | - Charles T. Anderson
- Department of Physiology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois 60611
| | - Pat Levitt
- Zilkha Neurogenetics Institute, Department of Cell and Neurobiology, Keck School of Medicine, University of Southern California, Los Angeles, California 90089, and
| | - Gordon M. G. Shepherd
- Department of Physiology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois 60611
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47
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Judson MC, Eagleson KL, Wang L, Levitt P. Evidence of cell-nonautonomous changes in dendrite and dendritic spine morphology in the met-signaling-deficient mouse forebrain. J Comp Neurol 2011; 518:4463-78. [PMID: 20853516 DOI: 10.1002/cne.22467] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Human genetic findings and murine neuroanatomical expression mapping have intersected to implicate Met receptor tyrosine kinase signaling in the development of forebrain circuits controlling social and emotional behaviors that are atypical in autism-spectrum disorders (ASD). To clarify roles for Met signaling during forebrain circuit development in vivo, we generated mutant mice (Emx1(Cre)/Met(fx/fx)) with an Emx1-Cre-driven deletion of signaling-competent Met in dorsal pallially derived forebrain neurons. Morphometric analyses of Lucifer yellow-injected pyramidal neurons in postnatal day 40 anterior cingulate cortex (ACC) revealed no statistically significant changes in total dendritic length but a selective reduction in apical arbor length distal to the soma in Emx1(Cre)/Met(fx/fx) neurons relative to wild type, consistent with a decrease in the total tissue volume sampled by individual arbors in the cortex. The effects on dendritic structure appear to be circuit-selective, insofar as basal arbor length was increased in Emx1(Cre)/Met(fx/fx) layer 2/3 neurons. Spine number was not altered on the Emx1(Cre)/Met(fx/fx) pyramidal cell populations studied, but spine head volume was significantly increased (∼20%). Cell-nonautonomous, circuit-level influences of Met signaling on dendritic development were confirmed by studies of medium spiny neurons (MSN), which do not express Met but receive Met-expressing corticostriatal afferents during development. Emx1(Cre)/Met(fx/fx) MSN exhibited robust increases in total arbor length (∼20%). As in the neocortex, average spine head volume was also increased (∼12%). These data demonstrate that a developmental loss of presynaptic Met receptor signaling can affect postsynaptic morphogenesis and suggest a mechanism whereby attenuated Met signaling could disrupt both local and long-range connectivity within circuits relevant to ASD.
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Affiliation(s)
- Matthew C Judson
- Vanderbilt University Medical Center, Nashville, Tennessee 37203, USA
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48
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Eagleson KL, Campbell DB, Thompson BL, Bergman MY, Levitt P. The autism risk genes MET and PLAUR differentially impact cortical development. Autism Res 2010; 4:68-83. [PMID: 21328570 DOI: 10.1002/aur.172] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2010] [Accepted: 11/01/2010] [Indexed: 02/06/2023]
Abstract
Candidate risk genes for autism spectrum disorder (ASD) have been identified, but the challenge of determining their contribution to pathogenesis remains. We previously identified two ASD risk genes encoding the receptor tyrosine kinase MET and the urokinase plasminogen activator receptor (PLAUR), which is thought to modulate availability of the MET ligand. We also reported a role for Met signaling in cortical interneuron development in vitro and a reduction of these neurons in uPAR (mouse ortholog of PLAUR) null mice, suggesting that disruption of either gene impacts cortical development similarly. Here, we modify this conclusion, reporting that interneuron numbers are unchanged in the neocortex of Met(fx/fx) / Dlx5/6(cre) mice, in which Met is ablated from cells arising from the ventral telencephalon (VTel). Consistent with this, Met transcript is not detected in the VTel during interneuron genesis and migration; furthermore, during the postnatal period of interneuron maturation, Met is co-expressed in glutamatergic projection neurons, but not interneurons. Low levels of Met protein are expressed in the VTel at E12.5 and E14.5, likely reflecting the arrival of Met containing corticofugal axons. Met expression, however, is induced in E12.5 VTel cells after 2 days in vitro, perhaps underlying discrepancies between observations in vitro and in Met(fx/fx) / Dlx5/6(cre) mice. We suggest that, in vivo, Met impacts the development of cortical projection neurons, whereas uPAR influences interneuron maturation. An altered balance between excitation and inhibition has been postulated as a biological mechanism for ASD; this imbalance could arise from different risk genes differentially affecting either or both elements.
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Affiliation(s)
- Kathie L Eagleson
- Zilkha Neurogenetic Institute, Keck School of Medicine at USC, Los Angeles, California 90033, USA.
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49
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Judson MC, Amaral DG, Levitt P. Conserved subcortical and divergent cortical expression of proteins encoded by orthologs of the autism risk gene MET. ACTA ACUST UNITED AC 2010; 21:1613-26. [PMID: 21127014 PMCID: PMC3116738 DOI: 10.1093/cercor/bhq223] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Met receptor tyrosine kinase signaling regulates the growth and development of axons and may contribute to the wiring of cortical and limbic circuits in the rodent forebrain. Whether the orthologous MET receptor functions similarly in the developing primate forebrain is not known but is of considerable interest considering the association of variant MET alleles with social and communication phenotypes in autism. To begin addressing this question, we compared Met/MET protein expression in the developing mouse and rhesus macaque forebrain. There was a strong temporal conservation of expression during the time of rapid axon development and the onset of robust synapse formation. Expression patterns of Met/MET in limbic-related structures were almost identical between species. In marked contrast, there was highly divergent expression in the neocortex. In mouse, Met was broadly distributed throughout neocortex. In the macaque, robust MET expression was largely restricted to the posterior cingulate, inferior temporal, posterior parietal, and visual cortices, including face processing regions. The pattern is consistent with the importance of vision in the social repertoire of the primate. Collectively, these data suggest a conserved developmental function of the MET receptor in wiring together limbic and neocortical circuits that facilitate species-appropriate responses, including social behavior.
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Affiliation(s)
- Matthew C Judson
- Graduate Program in Neuroscience, Vanderbilt University Medical Center, Nashville, TN 37203, USA.
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50
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State MW. The genetics of child psychiatric disorders: focus on autism and Tourette syndrome. Neuron 2010; 68:254-69. [PMID: 20955933 DOI: 10.1016/j.neuron.2010.10.004] [Citation(s) in RCA: 128] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/02/2010] [Indexed: 12/23/2022]
Abstract
Investigations into the genetics of child psychiatric disorders have finally begun to shed light on molecular and cellular mechanisms of psychopathology. The first strains of success in this notoriously difficult area of inquiry are the result of an increasingly sophisticated appreciation of the allelic architecture of common neuropsychiatric and neurodevelopmental disorders, the consolidation of large patient cohorts now beginning to reach sufficient size to power reliable studies, the emergence of genomic tools enabling comprehensive investigations of rare as well as common genetic variation, and advances in developmental neuroscience that are fueling the rapid translation of genetic findings.
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Affiliation(s)
- Matthew W State
- Department of Child Psychiatry, Yale University School of Medicine, New Haven, CT 06510, USA.
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