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Vaissiere T, Michaelson SD, Creson T, Goins J, Fürth D, Balazsfi D, Rojas C, Golovin R, Meletis K, Miller CA, O’Connor D, Fontolan L, Rumbaugh G. Syngap1 Promotes Cognitive Function through Regulation of Cortical Sensorimotor Dynamics. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2023.09.27.559787. [PMID: 37808765 PMCID: PMC10557642 DOI: 10.1101/2023.09.27.559787] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/10/2023]
Abstract
Perception, a cognitive construct, emerges through sensorimotor integration (SMI). The genetic mechanisms that shape SMI required for perception are unknown. Here, we demonstrate in mice that expression of the autism/intellectual disability gene, Syngap1, in cortical excitatory neurons is required for formation of somatomotor networks that promote SMI-mediated perception. Cortical Syngap1 expression was necessary and sufficient for setting tactile sensitivity, sustaining tactile object exploration, and promoting tactile learning. Mice with deficient Syngap1 expression exhibited impaired neural dynamics induced by exploratory touches within a cortical-thalamic network known to promote attention and perception. Disrupted neuronal dynamics were associated with circuit-specific long-range synaptic connectivity abnormalities. Our data support a model where autonomous Syngap1 expression in cortical excitatory neurons promotes cognitive abilities through assembly of circuits that integrate temporally-overlapping sensory and motor signals, a process that promotes perception and attention. These data provide systems-level insights into the robust association between Syngap1 expression and cognitive ability.
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Affiliation(s)
- Thomas Vaissiere
- Department of Neuroscience, The Herbert Wertheim UF Scripps Institute for Biomedical Innovation & Technology, Jupiter, FL, USA
| | - Sheldon D. Michaelson
- Department of Neuroscience, The Herbert Wertheim UF Scripps Institute for Biomedical Innovation & Technology, Jupiter, FL, USA
| | - Thomas Creson
- Department of Neuroscience, The Herbert Wertheim UF Scripps Institute for Biomedical Innovation & Technology, Jupiter, FL, USA
| | - Jessie Goins
- Department of Neuroscience, The Herbert Wertheim UF Scripps Institute for Biomedical Innovation & Technology, Jupiter, FL, USA
| | - Daniel Fürth
- SciLifeLab, Department of Immunology, Genetics & Pathology, Uppsala University, Uppsala, Sweden
| | - Diana Balazsfi
- Department of Neuroscience, The Herbert Wertheim UF Scripps Institute for Biomedical Innovation & Technology, Jupiter, FL, USA
| | - Camilo Rojas
- Department of Neuroscience, The Herbert Wertheim UF Scripps Institute for Biomedical Innovation & Technology, Jupiter, FL, USA
| | - Randall Golovin
- Department of Neuroscience, The Herbert Wertheim UF Scripps Institute for Biomedical Innovation & Technology, Jupiter, FL, USA
| | | | - Courtney A. Miller
- Department of Neuroscience, The Herbert Wertheim UF Scripps Institute for Biomedical Innovation & Technology, Jupiter, FL, USA
- Department of Molecular Medicine, UF Scripps Biomedical Research, Jupiter, FL, USA
| | - Daniel O’Connor
- Department of Neuroscience, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Lorenzo Fontolan
- Aix-Marseille Université, INSERM, INMED, Turing Centre for Living Systems, Marseille, 13009, France
| | - Gavin Rumbaugh
- Department of Neuroscience, The Herbert Wertheim UF Scripps Institute for Biomedical Innovation & Technology, Jupiter, FL, USA
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Katsanevaki D, Till SM, Buller-Peralta I, Nawaz MS, Louros SR, Kapgal V, Tiwari S, Walsh D, Anstey NJ, Petrović NG, Cormack A, Salazar-Sanchez V, Harris A, Farnworth-Rowson W, Sutherland A, Watson TC, Dimitrov S, Jackson AD, Arkell D, Biswal S, Dissanayake KN, Mizen LAM, Perentos N, Jones MW, Cousin MA, Booker SA, Osterweil EK, Chattarji S, Wyllie DJA, Gonzalez-Sulser A, Hardt O, Wood ER, Kind PC. Key roles of C2/GAP domains in SYNGAP1-related pathophysiology. Cell Rep 2024; 43:114733. [PMID: 39269903 DOI: 10.1016/j.celrep.2024.114733] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2023] [Revised: 07/30/2024] [Accepted: 08/23/2024] [Indexed: 09/15/2024] Open
Abstract
Mutations in SYNGAP1 are a common genetic cause of intellectual disability (ID) and a risk factor for autism. SYNGAP1 encodes a synaptic GTPase-activating protein (GAP) that has both signaling and scaffolding roles. Most pathogenic variants of SYNGAP1 are predicted to result in haploinsufficiency. However, some affected individuals carry missense mutations in its calcium/lipid binding (C2) and GAP domains, suggesting that many clinical features result from loss of functions carried out by these domains. To test this hypothesis, we targeted the exons encoding the C2 and GAP domains of SYNGAP. Rats heterozygous for this deletion exhibit reduced exploration and fear extinction, altered social investigation, and spontaneous seizures-key phenotypes shared with Syngap heterozygous null rats. Together, these findings indicate that the reduction of SYNGAP C2/GAP domain function is a main feature of SYNGAP haploinsufficiency. This rat model provides an important system for the study of ID, autism, and epilepsy.
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Affiliation(s)
- Danai Katsanevaki
- Simons Initiative for the Developing Brain, Centre for Discovery Brain Sciences, University of Edinburgh, EH8 9XD Edinburgh, UK; Patrick Wild Centre, University of Edinburgh, EH8 9XD Edinburgh, UK
| | - Sally M Till
- Simons Initiative for the Developing Brain, Centre for Discovery Brain Sciences, University of Edinburgh, EH8 9XD Edinburgh, UK; Patrick Wild Centre, University of Edinburgh, EH8 9XD Edinburgh, UK; Centre for Brain Development and Repair, Instem, Bangalore 560065, India
| | - Ingrid Buller-Peralta
- Simons Initiative for the Developing Brain, Centre for Discovery Brain Sciences, University of Edinburgh, EH8 9XD Edinburgh, UK; Patrick Wild Centre, University of Edinburgh, EH8 9XD Edinburgh, UK
| | - Mohammad Sarfaraz Nawaz
- Simons Initiative for the Developing Brain, Centre for Discovery Brain Sciences, University of Edinburgh, EH8 9XD Edinburgh, UK; Centre for Brain Development and Repair, Instem, Bangalore 560065, India
| | - Susana R Louros
- Simons Initiative for the Developing Brain, Centre for Discovery Brain Sciences, University of Edinburgh, EH8 9XD Edinburgh, UK; Patrick Wild Centre, University of Edinburgh, EH8 9XD Edinburgh, UK
| | - Vijayakumar Kapgal
- Centre for Brain Development and Repair, Instem, Bangalore 560065, India; The University of Transdisciplinary Health Sciences and Technology, Bangalore 560065, India
| | - Shashank Tiwari
- Centre for Brain Development and Repair, Instem, Bangalore 560065, India
| | - Darren Walsh
- Simons Initiative for the Developing Brain, Centre for Discovery Brain Sciences, University of Edinburgh, EH8 9XD Edinburgh, UK; Patrick Wild Centre, University of Edinburgh, EH8 9XD Edinburgh, UK
| | - Natasha J Anstey
- Simons Initiative for the Developing Brain, Centre for Discovery Brain Sciences, University of Edinburgh, EH8 9XD Edinburgh, UK; Patrick Wild Centre, University of Edinburgh, EH8 9XD Edinburgh, UK; Centre for Brain Development and Repair, Instem, Bangalore 560065, India
| | - Nina G Petrović
- Simons Initiative for the Developing Brain, Centre for Discovery Brain Sciences, University of Edinburgh, EH8 9XD Edinburgh, UK; Patrick Wild Centre, University of Edinburgh, EH8 9XD Edinburgh, UK
| | - Alison Cormack
- Simons Initiative for the Developing Brain, Centre for Discovery Brain Sciences, University of Edinburgh, EH8 9XD Edinburgh, UK; Patrick Wild Centre, University of Edinburgh, EH8 9XD Edinburgh, UK
| | - Vanesa Salazar-Sanchez
- Simons Initiative for the Developing Brain, Centre for Discovery Brain Sciences, University of Edinburgh, EH8 9XD Edinburgh, UK; Patrick Wild Centre, University of Edinburgh, EH8 9XD Edinburgh, UK
| | - Anjanette Harris
- Simons Initiative for the Developing Brain, Centre for Discovery Brain Sciences, University of Edinburgh, EH8 9XD Edinburgh, UK; Patrick Wild Centre, University of Edinburgh, EH8 9XD Edinburgh, UK
| | - William Farnworth-Rowson
- Simons Initiative for the Developing Brain, Centre for Discovery Brain Sciences, University of Edinburgh, EH8 9XD Edinburgh, UK; Patrick Wild Centre, University of Edinburgh, EH8 9XD Edinburgh, UK
| | - Andrew Sutherland
- Simons Initiative for the Developing Brain, Centre for Discovery Brain Sciences, University of Edinburgh, EH8 9XD Edinburgh, UK; Patrick Wild Centre, University of Edinburgh, EH8 9XD Edinburgh, UK
| | - Thomas C Watson
- Simons Initiative for the Developing Brain, Centre for Discovery Brain Sciences, University of Edinburgh, EH8 9XD Edinburgh, UK; Patrick Wild Centre, University of Edinburgh, EH8 9XD Edinburgh, UK
| | - Siyan Dimitrov
- Simons Initiative for the Developing Brain, Centre for Discovery Brain Sciences, University of Edinburgh, EH8 9XD Edinburgh, UK; Patrick Wild Centre, University of Edinburgh, EH8 9XD Edinburgh, UK
| | - Adam D Jackson
- Simons Initiative for the Developing Brain, Centre for Discovery Brain Sciences, University of Edinburgh, EH8 9XD Edinburgh, UK; Patrick Wild Centre, University of Edinburgh, EH8 9XD Edinburgh, UK; Centre for Brain Development and Repair, Instem, Bangalore 560065, India
| | - Daisy Arkell
- Simons Initiative for the Developing Brain, Centre for Discovery Brain Sciences, University of Edinburgh, EH8 9XD Edinburgh, UK; Patrick Wild Centre, University of Edinburgh, EH8 9XD Edinburgh, UK
| | | | - Kosala N Dissanayake
- Simons Initiative for the Developing Brain, Centre for Discovery Brain Sciences, University of Edinburgh, EH8 9XD Edinburgh, UK; Patrick Wild Centre, University of Edinburgh, EH8 9XD Edinburgh, UK
| | - Lindsay A M Mizen
- Simons Initiative for the Developing Brain, Centre for Discovery Brain Sciences, University of Edinburgh, EH8 9XD Edinburgh, UK; Patrick Wild Centre, University of Edinburgh, EH8 9XD Edinburgh, UK
| | - Nikolas Perentos
- Department of Veterinary Medicine, University of Nicosia School of Veterinary Medicine, 2414 Nicosia, Cyprus
| | - Matt W Jones
- School of Physiology, Pharmacology, and Neuroscience, University of Bristol, Biomedical Sciences Building, University Walk, BS8 1TD Bristol, UK
| | - Michael A Cousin
- Simons Initiative for the Developing Brain, Centre for Discovery Brain Sciences, University of Edinburgh, EH8 9XD Edinburgh, UK; Patrick Wild Centre, University of Edinburgh, EH8 9XD Edinburgh, UK; Centre for Brain Development and Repair, Instem, Bangalore 560065, India
| | - Sam A Booker
- Simons Initiative for the Developing Brain, Centre for Discovery Brain Sciences, University of Edinburgh, EH8 9XD Edinburgh, UK; Patrick Wild Centre, University of Edinburgh, EH8 9XD Edinburgh, UK
| | - Emily K Osterweil
- Simons Initiative for the Developing Brain, Centre for Discovery Brain Sciences, University of Edinburgh, EH8 9XD Edinburgh, UK; Patrick Wild Centre, University of Edinburgh, EH8 9XD Edinburgh, UK
| | - Sumantra Chattarji
- Simons Initiative for the Developing Brain, Centre for Discovery Brain Sciences, University of Edinburgh, EH8 9XD Edinburgh, UK; Patrick Wild Centre, University of Edinburgh, EH8 9XD Edinburgh, UK; Centre for Brain Development and Repair, Instem, Bangalore 560065, India
| | - David J A Wyllie
- Simons Initiative for the Developing Brain, Centre for Discovery Brain Sciences, University of Edinburgh, EH8 9XD Edinburgh, UK; Patrick Wild Centre, University of Edinburgh, EH8 9XD Edinburgh, UK; Centre for Brain Development and Repair, Instem, Bangalore 560065, India
| | - Alfredo Gonzalez-Sulser
- Simons Initiative for the Developing Brain, Centre for Discovery Brain Sciences, University of Edinburgh, EH8 9XD Edinburgh, UK; Patrick Wild Centre, University of Edinburgh, EH8 9XD Edinburgh, UK
| | - Oliver Hardt
- Simons Initiative for the Developing Brain, Centre for Discovery Brain Sciences, University of Edinburgh, EH8 9XD Edinburgh, UK; Patrick Wild Centre, University of Edinburgh, EH8 9XD Edinburgh, UK; Centre for Brain Development and Repair, Instem, Bangalore 560065, India; Department of Psychology, McGill University, Montreal, QC H3A 1G1, Canada
| | - Emma R Wood
- Simons Initiative for the Developing Brain, Centre for Discovery Brain Sciences, University of Edinburgh, EH8 9XD Edinburgh, UK; Patrick Wild Centre, University of Edinburgh, EH8 9XD Edinburgh, UK; Centre for Brain Development and Repair, Instem, Bangalore 560065, India
| | - Peter C Kind
- Simons Initiative for the Developing Brain, Centre for Discovery Brain Sciences, University of Edinburgh, EH8 9XD Edinburgh, UK; Patrick Wild Centre, University of Edinburgh, EH8 9XD Edinburgh, UK; Centre for Brain Development and Repair, Instem, Bangalore 560065, India.
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Ribeiro-Constante J, Tristán-Noguero A, Martínez Calvo FF, Ibañez-Mico S, Peña Segura JL, Ramos-Fernández JM, Moyano Chicano MDC, Camino León R, Soto Insuga V, González Alguacil E, Valera Dávila C, Fernández-Jaén A, Plans L, Camacho A, Visa-Reñé N, Martin-Tamayo Blázquez MDP, Paredes-Carmona F, Marti-Carrera I, Hernández-Fabián A, Tomas Davi M, Sanchez MC, Herraiz LC, Pita PF, Gonzalez TB, O'Callaghan M, Iglesias Santa Polonia FF, Cazorla MR, Ferrando Lucas MT, González-Meneses A, Sala-Coromina J, Macaya A, Lasa-Aranzasti A, Cueto-González AM, Valera Párraga F, Campistol Plana J, Serrano M, Alonso X, Del Castillo-Berges D, Schwartz-Palleja M, Illescas S, Ramírez Camacho A, Sans Capdevila O, García-Cazorla A, Bayés À, Alonso-Colmenero I. Developmental outcome of electroencephalographic findings in SYNGAP1 encephalopathy. Front Cell Dev Biol 2024; 12:1321282. [PMID: 38505260 PMCID: PMC10948473 DOI: 10.3389/fcell.2024.1321282] [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: 10/13/2023] [Accepted: 01/22/2024] [Indexed: 03/21/2024] Open
Abstract
SYNGAP1 haploinsufficiency results in a developmental and epileptic encephalopathy (DEE) causing generalized epilepsies accompanied by a spectrum of neurodevelopmental symptoms. Concerning interictal epileptiform discharges (IEDs) in electroencephalograms (EEG), potential biomarkers have been postulated, including changes in background activity, fixation-off sensitivity (FOS) or eye closure sensitivity (ECS). In this study we clinically evaluate a new cohort of 36 SYNGAP1-DEE individuals. Standardized questionnaires were employed to collect clinical, electroencephalographic and genetic data. We investigated electroencephalographic findings, focusing on the cortical distribution of interictal abnormalities and their changes with age. Among the 36 SYNGAP1-DEE cases 18 presented variants in the SYNGAP1 gene that had never been previously reported. The mean age of diagnosis was 8 years and 8 months, ranging from 2 to 17 years, with 55.9% being male. All subjects had global neurodevelopmental/language delay and behavioral abnormalities; 83.3% had moderate to profound intellectual disability (ID), 91.7% displayed autistic traits, 73% experienced sleep disorders and 86.1% suffered from epileptic seizures, mainly eyelid myoclonia with absences (55.3%). A total of 63 VEEGs were revised, observing a worsening of certain EEG findings with increasing age. A disorganized background was observed in all age ranges, yet this was more common among older cases. The main IEDs were bilateral synchronous and asynchronous posterior discharges, accounting for ≥50% in all age ranges. Generalized alterations with maximum amplitude in the anterior region showed as the second most frequent IED (≥15% in all age ranges) and were also more common with increasing age. Finally, diffuse fast activity was much more prevalent in cases with 6 years or older. To the best of our knowledge, this is the first study to analyze EEG features across different age groups, revealing an increase in interictal abnormalities over infancy and adolescence. Our findings suggest that SYNGAP1 haploinsufficiency has complex effects in human brain development, some of which might unravel at different developmental stages. Furthermore, they highlight the potential of baseline EEG to identify candidate biomarkers and the importance of natural history studies to develop specialized therapies and clinical trials.
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Affiliation(s)
| | - Alba Tristán-Noguero
- Department of Genetics, Microbiology and Statistics, University of Barcelona, Barcelona, Spain
- Molecular Physiology of the Synapse Laboratory, Institut de Recerca Sant Pau (IR Sant Pau), Universitat Autònoma de Barcelona, Barcelona, Spain
| | | | | | - José Luis Peña Segura
- Pediatric Neurology Department, Hospital Universitario Miguel Servet, Zaragoza, Spain
| | | | | | - Rafael Camino León
- Pediatric Neurology Department, Hospital Universitario Reina Sofía, Córdoba, Spain
| | - Víctor Soto Insuga
- Pediatric Neurology Department, Hospital Universitario Infantil del Niño Jesús, Madrid, Spain
| | - Elena González Alguacil
- Pediatric Neurology Department, Hospital Universitario Infantil del Niño Jesús, Madrid, Spain
| | - Carlos Valera Dávila
- Pediatric Neurology Department Sant Joan de Déu (SJD) Children’s Hospital, Barcelona, Spain
| | - Alberto Fernández-Jaén
- Pediatric Neurology Department, Neurogenetics Section, Hospital Universitario Quironsalud, Madrid, Spain
| | - Laura Plans
- Mental Health in Intellectual Disability Specialized Service Althaia, Xarxa Assistencial, Manresa, Spain
| | - Ana Camacho
- Pediatric Neurology Department, Hospital 12 de Octubre, Universidad Complutense de Madrid, Madrid, Spain
| | - Nuria Visa-Reñé
- Paediatric Department, Arnau de Vilanova University Hospital, Lleida, Spain
| | | | | | - Itxaso Marti-Carrera
- Pediatric Neurology Department, Hospital Universitario Donostia, San Sebastian, Spain
| | | | - Meritxell Tomas Davi
- Mental Health in Intellectual Disability Specialized Service Althaia, Xarxa Assistencial, Manresa, Spain
| | - Merce Casadesus Sanchez
- Mental Health in Intellectual Disability Specialized Service Althaia, Xarxa Assistencial, Manresa, Spain
| | | | - Patricia Fuentes Pita
- Pediatric Neurology Department, Hospital Clínico Universitario Santiago de Compostela, Santiago de Compostela, Spain
| | | | - Mar O'Callaghan
- Pediatric Neurology Department Sant Joan de Déu (SJD) Children’s Hospital, Barcelona, Spain
| | | | - María Rosario Cazorla
- Pediatric Neurology Department, Puerta de Hierro Majadahonda Universitary Hospital, Madrid, Spain
| | | | | | - Júlia Sala-Coromina
- Pediatric Neurology Department, Vall d'Hebron University Hospital, Universitat Autónoma de Barcelona, Bercelona, Spain
| | - Alfons Macaya
- Pediatric Neurology Department, Vall d'Hebron University Hospital, Universitat Autónoma de Barcelona, Bercelona, Spain
| | - Amaia Lasa-Aranzasti
- Department of Clinical and Molecular Genetic Vall d'Hebron University Hospital, Universitat Autónoma de Barcelona, Bercelona, Spain
| | - Anna Ma Cueto-González
- Department of Clinical and Molecular Genetic Vall d'Hebron University Hospital, Universitat Autónoma de Barcelona, Bercelona, Spain
| | | | - Jaume Campistol Plana
- Pediatric Neurology Department Sant Joan de Déu (SJD) Children’s Hospital, Barcelona, Spain
| | - Mercedes Serrano
- Pediatric Neurology Department Sant Joan de Déu (SJD) Children’s Hospital, Barcelona, Spain
| | - Xenia Alonso
- Pediatric Neurology Department Sant Joan de Déu (SJD) Children’s Hospital, Barcelona, Spain
| | - Diego Del Castillo-Berges
- Molecular Physiology of the Synapse Laboratory, Institut de Recerca Sant Pau (IR Sant Pau), Universitat Autònoma de Barcelona, Barcelona, Spain
| | - Marc Schwartz-Palleja
- Eurecat, Technology Center of Catalonia, Multimedia Technologies, Barcelona, Spain
- Center for Brain and Cognition (CBC), Department of Information Technologies and Communications (DTIC), Pompeu Fabra University, Barcelona, Catalonia, Spain
- Department of Experimental and Health Sciences, Universitat Pompeu Fabra, Barcelona, Spain
| | - Sofía Illescas
- Pediatric Neurometabolism: Neural Communication Mechanisms and Personalized Therapies Pediatric Neurology Department: Neural Communication Mechanisms and Personalized Therapies Institut de Recerca Sant Joan de Déu, Esplugues de Llobregat, Spain
| | - Alia Ramírez Camacho
- Department of Child Neurology, Epilepsy and Neurophysiology Unit, Member of the ERN EpiCARE, Hospital Sant Joan de Dèu, Barcelona, Spain
| | - Oscar Sans Capdevila
- Pediatric Neurology Department Sant Joan de Déu (SJD) Children’s Hospital, Barcelona, Spain
| | - Angeles García-Cazorla
- Pediatric Neurology Department Sant Joan de Déu (SJD) Children’s Hospital, Barcelona, Spain
| | - Àlex Bayés
- Molecular Physiology of the Synapse Laboratory, Institut de Recerca Sant Pau (IR Sant Pau), Universitat Autònoma de Barcelona, Barcelona, Spain
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Megagiannis P, Suresh R, Rouleau GA, Zhou Y. Reversibility and therapeutic development for neurodevelopmental disorders, insights from genetic animal models. Adv Drug Deliv Rev 2022; 191:114562. [PMID: 36183904 DOI: 10.1016/j.addr.2022.114562] [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: 04/25/2022] [Revised: 08/30/2022] [Accepted: 09/24/2022] [Indexed: 01/24/2023]
Abstract
Neurodevelopmental Disorders (NDDs) encompass a broad spectrum of conditions resulting from atypical brain development. Over the past decades, we have had the fortune to witness enormous progress in diagnosis, etiology discovery, modeling, and mechanistic understanding of NDDs from both fundamental and clinical research. Here, we review recent neurobiological advances from experimental models of NDDs. We introduce several examples and highlight breakthroughs in reversal studies of phenotypes using genetically engineered models of NDDs. The in-depth understanding of brain pathophysiology underlying NDDs and evaluations of reversibility in animal models paves the foundation for discovering novel treatment options. We discuss how the expanding property of cutting-edge technologies, such as gene editing and AAV-mediated gene delivery, are leveraged in animal models for the therapeutic development of NDDs. We envision opportunities and challenges toward faithful modeling and fruitful clinical translation.
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Affiliation(s)
- Platon Megagiannis
- Department of Neurology and Neurosurgery, Montreal Neurological Institute-Hospital; Faculty of Medicine and Health Sciences, McGill University, Montreal, Quebec H3A 2B4, Canada
| | - Rahul Suresh
- Department of Neurology and Neurosurgery, Montreal Neurological Institute-Hospital; Faculty of Medicine and Health Sciences, McGill University, Montreal, Quebec H3A 2B4, Canada
| | - Guy A Rouleau
- Department of Neurology and Neurosurgery, Montreal Neurological Institute-Hospital; Faculty of Medicine and Health Sciences, McGill University, Montreal, Quebec H3A 2B4, Canada
| | - Yang Zhou
- Department of Neurology and Neurosurgery, Montreal Neurological Institute-Hospital; Faculty of Medicine and Health Sciences, McGill University, Montreal, Quebec H3A 2B4, Canada.
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Sahasrabudhe A, Begum F, Guevara CA, Morrison C, Hsiao K, Kezunovic N, Bozdagi-Gunal O, Benson DL. Cyfip1 Regulates SynGAP1 at Hippocampal Synapses. Front Synaptic Neurosci 2021; 12:581714. [PMID: 33613257 PMCID: PMC7892963 DOI: 10.3389/fnsyn.2020.581714] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2020] [Accepted: 12/23/2020] [Indexed: 11/13/2022] Open
Abstract
In humans, copy number variations in CYFIP1 appear to have sweeping physiological and structural consequences in the brain, either producing or altering the severity of intellectual disability, autism, and schizophrenia. Independently, SynGAP1 haploinsufficiency produces intellectual disability and, frequently, autism. Cyfip1 inhibits protein translation and promotes actin polymerization, and SynGAP1 is a synaptically localized Ras/Rap GAP. While these proteins are clearly distinct, studies investigating their functions in mice have shown that each regulates the maturation of synapses in the hippocampus and haploinsufficiency for either produces an exaggerated form of mGluR-dependent long-term depression, suggesting that some signaling pathways converge. In this study, we examined how Cyfip1 haploinsufficiency impacts SynGAP1 levels and localization, as well as potential sites for mechanistic interaction in mouse hippocampus. The data show that synaptic, but not total, levels of SynGAP1 in Cyfip1 +/- mice were abnormally low during early postnatal development and in adults. This may be in response to a shift in the balance of kinases that activate SynGAP1 as levels of Cdk5 were reduced and those of activated CaMKII were maintained in Cyfip1 +/- mice compared to wild-type mice. Alternatively, this could reflect altered actin dynamics as Rac1 activity in Cyfip1 +/- hippocampus was boosted significantly compared to wild-type mice, and levels of synaptic F-actin were generally enhanced due in part to an increase in the activity of the WAVE regulatory complex. Decreased synaptic SynGAP1 coupled with a CaMKII-mediated bias toward Rap1 inactivation at synapses is also consistent with increased levels of synaptic GluA2, increased AMPA receptor-mediated responses to stimulation, and increased levels of synaptic mGluR1/5 compared to wild-type mice. Collectively, our data suggest that Cyfip1 regulates SynGAP1 and the two proteins work coordinately at synapses to appropriately direct actin polymerization and GAP activity.
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Affiliation(s)
- Abhishek Sahasrabudhe
- Icahn School of Medicine at Mount Sinai, Nash Family Department of Neuroscience, Friedman Brain Institute, New York, NY, United States
| | - Fatema Begum
- Icahn School of Medicine at Mount Sinai, Nash Family Department of Neuroscience, Friedman Brain Institute, New York, NY, United States
| | - Christopher A Guevara
- Icahn School of Medicine at Mount Sinai, Nash Family Department of Neuroscience, Friedman Brain Institute, New York, NY, United States.,Graduate School of Biomedical Sciences, New York, NY, United States
| | - Chenel Morrison
- Icahn School of Medicine at Mount Sinai, Nash Family Department of Neuroscience, Friedman Brain Institute, New York, NY, United States
| | - Kuangfu Hsiao
- Icahn School of Medicine at Mount Sinai, Nash Family Department of Neuroscience, Friedman Brain Institute, New York, NY, United States
| | - Nebojsa Kezunovic
- Icahn School of Medicine at Mount Sinai, Nash Family Department of Neuroscience, Friedman Brain Institute, New York, NY, United States
| | - Ozlem Bozdagi-Gunal
- Department of Psychiatry, Rutgers New Jersey Medical School, Newark, NJ, United States
| | - Deanna L Benson
- Icahn School of Medicine at Mount Sinai, Nash Family Department of Neuroscience, Friedman Brain Institute, New York, NY, United States
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Identification of an individual with a SYGNAP1 pathogenic mutation in India. Mol Biol Rep 2020; 47:9225-9234. [PMID: 33090308 DOI: 10.1007/s11033-020-05915-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2020] [Accepted: 10/10/2020] [Indexed: 10/23/2022]
Abstract
Exome sequencing is a prominent tool to identify novel and deleterious mutations which could be non-sense, frameshift, and canonical splice-site mutations in a specific gene. De novo mutations in SYNGAP1, which codes for synaptic RAS-GTPase activating the protein, causes Intellectual disability (ID) and Autism Spectrum Disorder (ASD). SYNGAP1 related ASD/ID is one of the rare diseases that are detrimental to the healthy neuronal developmental and disrupts the global development of a child. We report the first SYNGAP1 heterozygous patient from Indian cohort. We report a case of a child of 2-year old with global developmental delay, microcephaly subtle dysmorphism, absence seizures, disrupted sleep, delay in learning a language, and eating problems. Upon further validation, the child has a few traits of ASD. Here, based on focused exome sequencing, we report a de novo heterozygous mutation in SYNGAP1 exon 11 with c. 1861 C > T (p.arg621ter). Currently, the child is on Atorvastatin, a RAS inhibitor, already available in the market for the treatment of hypercholesterolemia and has shown considerable improvement in global behaviour and cognitive development. The long-term follow up of the child's development would contribute to the already existing knowledge of the developmental trajectory in individuals with SYNGAP1 heterozygous mutation. In this report, we discuss the finding of a novel mutation in one of the genes, SYNGAP1, implicated in ASD/ID. Besides, we discuss the current treatment prescribed to the patient and the progress of global developmental of the child.
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7
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Gou G, Roca-Fernandez A, Kilinc M, Serrano E, Reig-Viader R, Araki Y, Huganir RL, de Quintana-Schmidt C, Rumbaugh G, Bayés À. SynGAP splice variants display heterogeneous spatio-temporal expression and subcellular distribution in the developing mammalian brain. J Neurochem 2020; 154:618-634. [PMID: 32068252 PMCID: PMC7754318 DOI: 10.1111/jnc.14988] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2019] [Revised: 02/04/2020] [Accepted: 02/17/2020] [Indexed: 11/28/2022]
Abstract
The SynGAP protein is a major regulator of synapse biology and neural circuit function. Genetic variants linked to epilepsy and intellectual disability disrupt synaptic function and neural excitability. SynGAP has been involved in multiple signaling pathways and can regulate small GTPases with very different roles. Yet, the molecular bases behind this pleiotropy are poorly understood. We hypothesize that different SynGAP isoforms will mediate different sets of functions and that deciphering their spatio-temporal expression and subcellular localization will accelerate understanding their multiple functions. Using isoform-specific antibodies recognizing SynGAP in mouse and human samples we found distinctive developmental expression patterns for all SynGAP isoforms in five mouse brain areas. Particularly noticeable was the delayed expression of SynGAP-α1 isoforms, which directly bind to postsynaptic density-95, in cortex and hippocampus during the first 2 weeks of postnatal development. Suggesting that during this period other isoforms would have a more prominent role. Furthermore, we observed subcellular localization differences between isoforms, particularly throughout postnatal development. Consistent with previous reports, SynGAP was enriched in the postsynaptic density in the mature forebrain. However, SynGAP was predominantly found in non-synaptic locations in a period of early postnatal development highly sensitive to SynGAP levels. While, α1 isoforms were always found enriched in the postsynaptic density, α2 isoforms changed from a non-synaptic to a mostly postsynaptic density localization with age and β isoforms were always found enriched in non-synaptic locations. The differential expression and subcellular distribution of SynGAP isoforms may contribute to isoform-specific regulation of small GTPases, explaining SynGAP pleiotropy.
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Affiliation(s)
- Gemma Gou
- Molecular Physiology of the Synapse Laboratory, Biomedical Research Institute Sant Pau (IIB Sant Pau), Barcelona, Spain.,Universitat Autònoma de Barcelona, Bellaterra (Cerdanyola del Vallès), Spain
| | | | - Murat Kilinc
- Department of Neuroscience, The Scripps Research Institute, Jupiter, FL, USA
| | - Elena Serrano
- Biobank, Biomedical Research Institute Sant Pau (IIB Sant Pau), Barcelona, Spain
| | - Rita Reig-Viader
- Molecular Physiology of the Synapse Laboratory, Biomedical Research Institute Sant Pau (IIB Sant Pau), Barcelona, Spain.,Universitat Autònoma de Barcelona, Bellaterra (Cerdanyola del Vallès), Spain
| | - Yoichi Araki
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD, USA.,Kavli Neuroscience Discovery Institute, Johns Hopkins University, Baltimore, MD, USA
| | - Richard L Huganir
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD, USA.,Kavli Neuroscience Discovery Institute, Johns Hopkins University, Baltimore, MD, USA
| | | | - Gavin Rumbaugh
- Department of Neuroscience, The Scripps Research Institute, Jupiter, FL, USA
| | - Àlex Bayés
- Molecular Physiology of the Synapse Laboratory, Biomedical Research Institute Sant Pau (IIB Sant Pau), Barcelona, Spain.,Universitat Autònoma de Barcelona, Bellaterra (Cerdanyola del Vallès), Spain
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8
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Twenty Years of SynGAP Research: From Synapses to Cognition. J Neurosci 2020; 40:1596-1605. [PMID: 32075947 DOI: 10.1523/jneurosci.0420-19.2020] [Citation(s) in RCA: 85] [Impact Index Per Article: 21.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2019] [Revised: 01/03/2020] [Accepted: 01/07/2020] [Indexed: 12/11/2022] Open
Abstract
SynGAP is a potent regulator of biochemical signaling in neurons and plays critical roles in neuronal function. It was first identified in 1998, and has since been extensively characterized as a mediator of synaptic plasticity. Because of its involvement in synaptic plasticity, SynGAP has emerged as a critical protein for normal cognitive function. In recent years, mutations in the SYNGAP1 gene have been shown to cause intellectual disability in humans and have been linked to other neurodevelopmental disorders, such as autism spectrum disorders and schizophrenia. While the structure and biochemical function of SynGAP have been well characterized, a unified understanding of the various roles of SynGAP at the synapse and its contributions to neuronal function remains to be achieved. In this review, we summarize and discuss the current understanding of the multifactorial role of SynGAP in regulating neuronal function gathered over the last two decades.
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9
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Li W, Pozzo-Miller L. Dysfunction of the corticostriatal pathway in autism spectrum disorders. J Neurosci Res 2019; 98:2130-2147. [PMID: 31758607 DOI: 10.1002/jnr.24560] [Citation(s) in RCA: 48] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2019] [Revised: 11/04/2019] [Accepted: 11/05/2019] [Indexed: 12/14/2022]
Abstract
The corticostriatal pathway that carries sensory, motor, and limbic information to the striatum plays a critical role in motor control, action selection, and reward. Dysfunction of this pathway is associated with many neurological and psychiatric disorders. Corticostriatal synapses have unique features in their cortical origins and striatal targets. In this review, we first describe axonal growth and synaptogenesis in the corticostriatal pathway during development, and then summarize the current understanding of the molecular bases of synaptic transmission and plasticity at mature corticostriatal synapses. Genes associated with autism spectrum disorder (ASD) have been implicated in axonal growth abnormalities, imbalance of the synaptic excitation/inhibition ratio, and altered long-term synaptic plasticity in the corticostriatal pathway. Here, we review a number of ASD-associated high-confidence genes, including FMR1, KMT2A, GRIN2B, SCN2A, NLGN1, NLGN3, MET, CNTNAP2, FOXP2, TSHZ3, SHANK3, PTEN, CHD8, MECP2, DYRK1A, RELN, FOXP1, SYNGAP1, and NRXN, and discuss their relevance to proper corticostriatal function.
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Affiliation(s)
- Wei Li
- Department of Neurobiology, The University of Alabama at Birmingham, Birmingham, AL, USA
| | - Lucas Pozzo-Miller
- Department of Neurobiology, The University of Alabama at Birmingham, Birmingham, AL, USA
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10
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Zhu F, Collins MO, Harmse J, Choudhary JS, Grant SGN, Komiyama NH. Cell-type-specific visualisation and biochemical isolation of endogenous synaptic proteins in mice. Eur J Neurosci 2019; 51:793-805. [PMID: 31621109 PMCID: PMC7079123 DOI: 10.1111/ejn.14597] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2019] [Revised: 09/07/2019] [Accepted: 10/08/2019] [Indexed: 01/01/2023]
Abstract
In recent years, the remarkable molecular complexity of synapses has been revealed, with over 1,000 proteins identified in the synapse proteome. Although it is known that different receptors and other synaptic proteins are present in different types of neurons, the extent of synapse diversity across the brain is largely unknown. This is mainly due to the limitations of current techniques. Here, we report an efficient method for the purification of synaptic protein complexes, fusing a high‐affinity tag to endogenous PSD95 in specific cell types. We also developed a strategy, which enables the visualisation of endogenous PSD95 with fluorescent‐protein tag in Cre‐recombinase‐expressing cells. We demonstrate the feasibility of proteomic analysis of synaptic protein complexes and visualisation of these in specific cell types. We find that the composition of PSD95 complexes purified from specific cell types differs from those extracted from tissues with diverse cellular composition. The results suggest that there might be differential interactions in the PSD95 complexes in different brain regions. We have detected differentially interacting proteins by comparing data sets from the whole hippocampus and the CA3 subfield of the hippocampus. Therefore, these novel conditional PSD95 tagging lines will not only serve as powerful tools for precisely dissecting synapse diversity in specific brain regions and subsets of neuronal cells, but also provide an opportunity to better understand brain region‐ and cell‐type‐specific alterations associated with various psychiatric/neurological diseases. These newly developed conditional gene tagging methods can be applied to many different synaptic proteins and will facilitate research on the molecular complexity of synapses.
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Affiliation(s)
- Fei Zhu
- Centre for Clinical Brain Sciences, University of Edinburgh, Edinburgh, UK
| | - Mark O Collins
- Department of Biomedical Science, The University of Sheffield, Sheffield, UK
| | - Johan Harmse
- The Wellcome Trust Sanger Institute, Cambridge, UK
| | - Jyoti S Choudhary
- Functional Proteomics Group, Chester Beatty Laboratories, Institute of Cancer Research, London, UK
| | - Seth G N Grant
- Centre for Clinical Brain Sciences, University of Edinburgh, Edinburgh, UK.,The Wellcome Trust Sanger Institute, Cambridge, UK.,Simons Initiative for the Developing Brain (SIDB), University of Edinburgh, Edinburgh, UK
| | - Noboru H Komiyama
- Centre for Clinical Brain Sciences, University of Edinburgh, Edinburgh, UK.,Simons Initiative for the Developing Brain (SIDB), University of Edinburgh, Edinburgh, UK.,The Patrick Wild Centre for Research into Autism, Fragile X Syndrome and Intellectual Disabilities, University of Edinburgh, Edinburgh, UK
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11
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Christensen NR, Čalyševa J, Fernandes EFA, Lüchow S, Clemmensen LS, Haugaard‐Kedström LM, Strømgaard K. PDZ Domains as Drug Targets. ADVANCED THERAPEUTICS 2019; 2:1800143. [PMID: 32313833 PMCID: PMC7161847 DOI: 10.1002/adtp.201800143] [Citation(s) in RCA: 63] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2018] [Revised: 03/25/2019] [Indexed: 12/14/2022]
Abstract
Protein-protein interactions within protein networks shape the human interactome, which often is promoted by specialized protein interaction modules, such as the postsynaptic density-95 (PSD-95), discs-large, zona occludens 1 (ZO-1) (PDZ) domains. PDZ domains play a role in several cellular functions, from cell-cell communication and polarization, to regulation of protein transport and protein metabolism. PDZ domain proteins are also crucial in the formation and stability of protein complexes, establishing an important bridge between extracellular stimuli detected by transmembrane receptors and intracellular responses. PDZ domains have been suggested as promising drug targets in several diseases, ranging from neurological and oncological disorders to viral infections. In this review, the authors describe structural and genetic aspects of PDZ-containing proteins and discuss the current status of the development of small-molecule and peptide modulators of PDZ domains. An overview of potential new therapeutic interventions in PDZ-mediated protein networks is also provided.
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Affiliation(s)
- Nikolaj R. Christensen
- Center for BiopharmaceuticalsDepartment of Drug Design and PharmacologyUniversity of CopenhagenUniversitetsparken 22100CopenhagenDenmark
| | - Jelena Čalyševa
- European Molecular Biology Laboratory (EMBL)Structural and Computational Biology UnitMeyerhofstraße 169117HeidelbergGermany
- EMBL International PhD ProgrammeFaculty of BiosciencesEMBL–Heidelberg UniversityGermany
| | - Eduardo F. A. Fernandes
- Center for BiopharmaceuticalsDepartment of Drug Design and PharmacologyUniversity of CopenhagenUniversitetsparken 22100CopenhagenDenmark
| | - Susanne Lüchow
- Department of Chemistry – BMCUppsala UniversityBox 576SE75123UppsalaSweden
| | - Louise S. Clemmensen
- Center for BiopharmaceuticalsDepartment of Drug Design and PharmacologyUniversity of CopenhagenUniversitetsparken 22100CopenhagenDenmark
| | - Linda M. Haugaard‐Kedström
- Center for BiopharmaceuticalsDepartment of Drug Design and PharmacologyUniversity of CopenhagenUniversitetsparken 22100CopenhagenDenmark
| | - Kristian Strømgaard
- Center for BiopharmaceuticalsDepartment of Drug Design and PharmacologyUniversity of CopenhagenUniversitetsparken 22100CopenhagenDenmark
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12
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Brimble E, Lee-Messer C, Nagy PL, Propst J, Ruzhnikov MRZ. Clinical Transcriptome Sequencing Confirms Activation of a Cryptic Splice Site in Suspected SYNGAP1-Related Disorder. Mol Syndromol 2019; 9:295-299. [PMID: 30800045 DOI: 10.1159/000492706] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/31/2018] [Indexed: 11/19/2022] Open
Abstract
SYNGAP1 encodes a brain-specific Ras GTPase activating protein (GAP) that regulates synaptic strength in glutamatergic neurons. Pathogenic variants in this gene are associated with a neurodevelopmental disorder characterized by intellectual and developmental disabilities, generalized epilepsy, hypotonia, and autism spectrum disorders. We describe a young male with suspected SYNGAP1-related disorder given clinical overlap and identification of an intronic variant of uncertain significance; clinical transcriptome analysis demonstrated activation of a cryptic acceptor splice site resulting in frameshift and introduction of a stop codon. This report highlights the utility of functional studies newly available to clinical practice in confirming a suspected genetic diagnosis, which can directly impact medical management and preclude the need for additional diagnostic testing.
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Affiliation(s)
- Elise Brimble
- Department of Neurology and Neurological Sciences, Stanford, CA
| | | | | | - Jennifer Propst
- Division of Clinical Genetics, Virginia Commonwealth University Health System, Richmond, VA, USA
| | - Maura R Z Ruzhnikov
- Department of Neurology and Neurological Sciences, Stanford, CA.,Division of Medical Genetics, Department of Pediatrics, Stanford Medicine, Stanford, CA
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13
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Liang H, Wang H, Wang S, Francis R, Paxinos G, Huang X. 3D imaging of PSD-95 in the mouse brain using the advanced CUBIC method. Mol Brain 2018; 11:50. [PMID: 30208945 PMCID: PMC6134724 DOI: 10.1186/s13041-018-0393-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2018] [Accepted: 09/05/2018] [Indexed: 11/10/2022] Open
Abstract
AIMS Postsynaptic density - 95 kDa protein (PSD95) is an important molecule on the postsynaptic membrane. It interacts with many other proteins and plays a pivotal role in learning and memory formation. Its distribution in the brain has been studied previously using in situ hybridization as well as immunohistochemistry. However, these studies are based on 2 dimensional (2D) sections and results are presented with a few sections. The present study aims to show PSD-95 distribution in 3 dimensions (3D) without slicing the brain tissue of C57BL/6 mice into sections using the advanced CUBIC technique. METHODS Immunofluorescent staining using a PSD-95 antibody was performed on a half of the mouse brain after clarifying it using the advanced CUBIC protocol. The brain tissue was imaged using a Zeiss Z1 light sheet microscope and 3D reconstruction was completed using the Arivis Vision 4 dimensional (4D) software. RESULTS The majority of brain nuclei have similar distribution pattern to what has been reported from in situ hybridization and immunohistochemical studies in the mouse. The signal can be easily followed in the 3D and their spatial relationship with adjacent structures clearly demarcated. In the present study, some fiber bundles also showed strong PSD-95 signal, which is different from what was shown in previous studies and need to be confirmed in future studies.
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Affiliation(s)
- Huazheng Liang
- Neurology Department, Shanghai No.1 People's Hospital (in the process of affiliation), School of Medicine, Tongji University, Shanghai, 200081, China. .,Neuroscience Research Australia, Randwick, NSW, 2031, Australia. .,School of Medicine, Western Sydney University, Campbelltown, NSW, 2560, Australia.
| | - Hongqin Wang
- Illawarra Health and Medical Research Institute, Wollongong, NSW, 2522, Australia
| | - Shaoshi Wang
- Neurology Department, Shanghai No.1 People's Hospital (in the process of affiliation), School of Medicine, Tongji University, Shanghai, 200081, China
| | - Richard Francis
- Biomedical Imaging Facility, Mark Wainwright Analytical Centre, The University of New South Wales, Kensington, NSW, 2052, Australia
| | - George Paxinos
- Neuroscience Research Australia, Randwick, NSW, 2031, Australia
| | - Xufeng Huang
- Illawarra Health and Medical Research Institute, Wollongong, NSW, 2522, Australia.
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14
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Chen S, Tisch N, Kegel M, Yerbes R, Hermann R, Hudalla H, Zuliani C, Gülcüler GS, Zwadlo K, von Engelhardt J, Ruiz de Almodóvar C, Martin-Villalba A. CNS Macrophages Control Neurovascular Development via CD95L. Cell Rep 2018; 19:1378-1393. [PMID: 28514658 DOI: 10.1016/j.celrep.2017.04.056] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2016] [Revised: 04/04/2017] [Accepted: 04/19/2017] [Indexed: 12/12/2022] Open
Abstract
The development of neurons and vessels shares striking anatomical and molecular features, and it is presumably orchestrated by an overlapping repertoire of extracellular signals. CNS macrophages have been implicated in various developmental functions, including the morphogenesis of neurons and vessels. However, whether CNS macrophages can coordinately influence neurovascular development and the identity of the signals involved therein is unclear. Here, we demonstrate that activity of the cell surface receptor CD95 regulates neuronal and vascular morphogenesis in the post-natal brain and retina. Furthermore, we identify CNS macrophages as the main source of CD95L, and macrophage-specific deletion thereof reduces both neurovascular complexity and synaptic activity in the brain. CD95L-induced neuronal and vascular growth is mediated through src-family kinase (SFK) and PI3K signaling. Together, our study highlights a coordinated neurovascular development instructed by CNS macrophage-derived CD95L, and it underlines the importance of macrophages for the establishment of the neurovascular network during CNS development.
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Affiliation(s)
- Si Chen
- Department of Molecular Neurobiology, German Cancer Research Center (DFKZ), 69120 Heidelberg, Germany
| | - Nathalie Tisch
- Biochemistry Center, Heidelberg University, 69120 Heidelberg, Germany
| | - Marcel Kegel
- Institute of Pathophysiology, University Medical Center of Johannes Gutenberg University Mainz, 55131 Mainz, Germany
| | - Rosario Yerbes
- Biochemistry Center, Heidelberg University, 69120 Heidelberg, Germany
| | - Robert Hermann
- Department of Molecular Neurobiology, German Cancer Research Center (DFKZ), 69120 Heidelberg, Germany
| | - Hannes Hudalla
- Department of Molecular Neurobiology, German Cancer Research Center (DFKZ), 69120 Heidelberg, Germany
| | - Cecilia Zuliani
- Department of Molecular Neurobiology, German Cancer Research Center (DFKZ), 69120 Heidelberg, Germany
| | - Gülce Sila Gülcüler
- Department of Molecular Neurobiology, German Cancer Research Center (DFKZ), 69120 Heidelberg, Germany
| | - Klara Zwadlo
- Department of Molecular Neurobiology, German Cancer Research Center (DFKZ), 69120 Heidelberg, Germany
| | - Jakob von Engelhardt
- Institute of Pathophysiology, University Medical Center of Johannes Gutenberg University Mainz, 55131 Mainz, Germany
| | | | - Ana Martin-Villalba
- Department of Molecular Neurobiology, German Cancer Research Center (DFKZ), 69120 Heidelberg, Germany.
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15
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Decrease of SYNGAP1 in GABAergic cells impairs inhibitory synapse connectivity, synaptic inhibition and cognitive function. Nat Commun 2016; 7:13340. [PMID: 27827368 PMCID: PMC5105197 DOI: 10.1038/ncomms13340] [Citation(s) in RCA: 59] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2016] [Accepted: 09/23/2016] [Indexed: 01/10/2023] Open
Abstract
Haploinsufficiency of the SYNGAP1 gene, which codes for a Ras GTPase-activating protein, impairs cognition both in humans and in mice. Decrease of Syngap1 in mice has been previously shown to cause cognitive deficits at least in part by inducing alterations in glutamatergic neurotransmission and premature maturation of excitatory connections. Whether Syngap1 plays a role in the development of cortical GABAergic connectivity and function remains unclear. Here, we show that Syngap1 haploinsufficiency significantly reduces the formation of perisomatic innervations by parvalbumin-positive basket cells, a major population of GABAergic neurons, in a cell-autonomous manner. We further show that Syngap1 haploinsufficiency in GABAergic cells derived from the medial ganglionic eminence impairs their connectivity, reduces inhibitory synaptic activity and cortical gamma oscillation power, and causes cognitive deficits. Our results indicate that Syngap1 plays a critical role in GABAergic circuit function and further suggest that Syngap1 haploinsufficiency in GABAergic circuits may contribute to cognitive deficits.
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16
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Abstract
UNLABELLED Previous studies have hypothesized that diverse genetic causes of intellectual disability (ID) and autism spectrum disorders (ASDs) converge on common cellular pathways. Testing this hypothesis requires detailed phenotypic analyses of animal models with genetic mutations that accurately reflect those seen in the human condition (i.e., have structural validity) and which produce phenotypes that mirror ID/ASDs (i.e., have face validity). We show that SynGAP haploinsufficiency, which causes ID with co-occurring ASD in humans, mimics and occludes the synaptic pathophysiology associated with deletion of the Fmr1 gene. Syngap(+/-) and Fmr1(-/y) mice show increases in basal protein synthesis and metabotropic glutamate receptor (mGluR)-dependent long-term depression that, unlike in their wild-type controls, is independent of new protein synthesis. Basal levels of phosphorylated ERK1/2 are also elevated in Syngap(+/-) hippocampal slices. Super-resolution microscopy reveals that Syngap(+/-) and Fmr1(-/y) mice show nanoscale alterations in dendritic spine morphology that predict an increase in biochemical compartmentalization. Finally, increased basal protein synthesis is rescued by negative regulators of the mGlu subtype 5 receptor and the Ras-ERK1/2 pathway, indicating that therapeutic interventions for fragile X syndrome may benefit patients with SYNGAP1 haploinsufficiency. SIGNIFICANCE STATEMENT As the genetics of intellectual disability (ID) and autism spectrum disorders (ASDs) are unraveled, a key issue is whether genetically divergent forms of these disorders converge on common biochemical/cellular pathways and hence may be amenable to common therapeutic interventions. This study compares the pathophysiology associated with the loss of fragile X mental retardation protein (FMRP) and haploinsufficiency of synaptic GTPase-activating protein (SynGAP), two prevalent monogenic forms of ID. We show that Syngap(+/-) mice phenocopy Fmr1(-/y) mice in the alterations in mGluR-dependent long-term depression, basal protein synthesis, and dendritic spine morphology. Deficits in basal protein synthesis can be rescued by pharmacological interventions that reduce the mGlu5 receptor-ERK1/2 signaling pathway, which also rescues the same deficit in Fmr1(-/y) mice. Our findings support the hypothesis that phenotypes associated with genetically diverse forms of ID/ASDs result from alterations in common cellular/biochemical pathways.
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17
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Abstract
A cardinal feature of early stages of human brain development centers on the sensory, cognitive, and emotional experiences that shape neuronal-circuit formation and refinement. Consequently, alterations in these processes account for many psychiatric and neurodevelopmental disorders. Neurodevelopment disorders affect 3-4% of the world population. The impact of these disorders presents a major challenge to clinicians, geneticists, and neuroscientists. Mutations that cause neurodevelopmental disorders are commonly found in genes encoding proteins that regulate synaptic function. Investigation of the underlying mechanisms using gain or loss of function approaches has revealed alterations in dendritic spine structure, function, and plasticity, consequently modulating the neuronal circuit formation and thereby raising the possibility of neurodevelopmental disorders resulting from synaptopathies. One such gene, SYNGAP1 (Synaptic Ras-GTPase-activating protein) has been shown to cause Intellectual Disability (ID) with comorbid Autism Spectrum Disorder (ASD) and epilepsy in children. SYNGAP1 is a negative regulator of Ras, Rap and of AMPA receptor trafficking to the postsynaptic membrane, thereby regulating not only synaptic plasticity, but also neuronal homeostasis. Recent studies on the neurophysiology of SYNGAP1, using Syngap1 mouse models, have provided deeper insights into how downstream signaling proteins and synaptic plasticity are regulated by SYNGAP1. This knowledge has led to a better understanding of the function of SYNGAP1 and suggests a potential target during critical period of development when the brain is more susceptible to therapeutic intervention.
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Affiliation(s)
- Nallathambi Jeyabalan
- Narayana Nethralaya Post-Graduate Institute of Ophthalmology, Narayana Nethralaya Foundation, Narayana Health City Bangalore, India
| | - James P Clement
- Neuroscience Unit, Jawaharlal Nehru Centre for Advanced Scientific Research Bangalore, India
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18
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Kozol RA, Cukier HN, Zou B, Mayo V, De Rubeis S, Cai G, Griswold AJ, Whitehead PL, Haines JL, Gilbert JR, Cuccaro ML, Martin ER, Baker JD, Buxbaum JD, Pericak-Vance MA, Dallman JE. Two knockdown models of the autism genes SYNGAP1 and SHANK3 in zebrafish produce similar behavioral phenotypes associated with embryonic disruptions of brain morphogenesis. Hum Mol Genet 2015; 24:4006-23. [PMID: 25882707 DOI: 10.1093/hmg/ddv138] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2014] [Accepted: 04/13/2015] [Indexed: 01/09/2023] Open
Abstract
Despite significant progress in the genetics of autism spectrum disorder (ASD), how genetic mutations translate to the behavioral changes characteristic of ASD remains largely unknown. ASD affects 1-2% of children and adults, and is characterized by deficits in verbal and non-verbal communication, and social interactions, as well as the presence of repetitive behaviors and/or stereotyped interests. ASD is clinically and etiologically heterogeneous, with a strong genetic component. Here, we present functional data from syngap1 and shank3 zebrafish loss-of-function models of ASD. SYNGAP1, a synaptic Ras GTPase activating protein, and SHANK3, a synaptic scaffolding protein, were chosen because of mounting evidence that haploinsufficiency in these genes is highly penetrant for ASD and intellectual disability (ID). Orthologs of both SYNGAP1 and SHANK3 are duplicated in the zebrafish genome and we find that all four transcripts (syngap1a, syngap1b, shank3a and shank3b) are expressed at the earliest stages of nervous system development with pronounced expression in the larval brain. Consistent with early expression of these genes, knockdown of syngap1b or shank3a cause common embryonic phenotypes including delayed mid- and hindbrain development, disruptions in motor behaviors that manifest as unproductive swim attempts, and spontaneous, seizure-like behaviors. Our findings indicate that both syngap1b and shank3a play novel roles in morphogenesis resulting in common brain and behavioral phenotypes.
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Affiliation(s)
- Robert A Kozol
- Department of Biology, University of Miami, Coral Gables, FL, USA,
| | - Holly N Cukier
- John P. Hussman Institute for Human Genomics, University of Miami Miller School of Medicine, Miami, FL, USA
| | - Bing Zou
- Department of Biology, University of Miami, Coral Gables, FL, USA
| | - Vera Mayo
- John P. Hussman Institute for Human Genomics, University of Miami Miller School of Medicine, Miami, FL, USA
| | - Silvia De Rubeis
- Seaver Autism Center for Research and Treatment, Department of Psychiatry, Friedman Brain Institute and Mindich Child Health and Development Institute, Icahn School of Medicine at Mount Sinai, New York, NY, USA and
| | - Guiqing Cai
- Seaver Autism Center for Research and Treatment, Department of Psychiatry, Friedman Brain Institute and Mindich Child Health and Development Institute, Icahn School of Medicine at Mount Sinai, New York, NY, USA and
| | - Anthony J Griswold
- John P. Hussman Institute for Human Genomics, University of Miami Miller School of Medicine, Miami, FL, USA
| | - Patrice L Whitehead
- John P. Hussman Institute for Human Genomics, University of Miami Miller School of Medicine, Miami, FL, USA
| | - Jonathan L Haines
- Department of Epidemiology and Biostatistics, Institute for Computational Biology, Case Western Reserve University School of Medicine, Cleveland, OH, USA
| | - John R Gilbert
- John P. Hussman Institute for Human Genomics, University of Miami Miller School of Medicine, Miami, FL, USA
| | - Michael L Cuccaro
- John P. Hussman Institute for Human Genomics, University of Miami Miller School of Medicine, Miami, FL, USA
| | - Eden R Martin
- John P. Hussman Institute for Human Genomics, University of Miami Miller School of Medicine, Miami, FL, USA
| | - James D Baker
- Department of Biology, University of Miami, Coral Gables, FL, USA
| | - Joseph D Buxbaum
- Seaver Autism Center for Research and Treatment, Department of Psychiatry, Friedman Brain Institute and Mindich Child Health and Development Institute, Icahn School of Medicine at Mount Sinai, New York, NY, USA and
| | - Margaret A Pericak-Vance
- John P. Hussman Institute for Human Genomics, University of Miami Miller School of Medicine, Miami, FL, USA
| | - Julia E Dallman
- Department of Biology, University of Miami, Coral Gables, FL, USA,
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19
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Ozkan ED, Creson TK, Kramár EA, Rojas C, Seese RR, Babyan AH, Shi Y, Lucero R, Xu X, Noebels JL, Miller CA, Lynch G, Rumbaugh G. Reduced cognition in Syngap1 mutants is caused by isolated damage within developing forebrain excitatory neurons. Neuron 2014; 82:1317-33. [PMID: 24945774 DOI: 10.1016/j.neuron.2014.05.015] [Citation(s) in RCA: 91] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/24/2014] [Indexed: 01/10/2023]
Abstract
Syngap1 haploinsufficiency is a common cause of sporadic intellectual disability. Syngap1 mutations disrupt developing pyramidal neurons, although it remains unclear if this process contributes to cognitive abnormalities. Here, we found that haploinsufficiency restricted to forebrain glutamatergic neurons was sufficient to disrupt cognition and removing mutations from this population prevented cognitive abnormalities. In contrast, manipulating Syngap1 function in GABAergic neurons had no effect on cognition, excitability, or neurotransmission, highlighting the specificity of Syngap1 mutations within forebrain excitatory neurons. Interestingly, cognitive abnormalities were reliably predicted by the emergence of enhanced excitatory synaptic function in mature superficial cortical pyramidal cells, which was a neurophysiological disruption caused by Syngap1 dysfunction in developing, but not adult, forebrain neurons. We conclude that reduced cognition in Syngap1 mutants is caused by isolated damage to developing forebrain glutamatergic neurons. This damage triggers secondary disruptions to synaptic homeostasis in mature cortical pyramidal cells, which perpetuates brain dysfunction into adulthood.
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Affiliation(s)
- Emin D Ozkan
- Department of Neuroscience, The Scripps Research Institute, Jupiter, FL 33458, USA
| | - Thomas K Creson
- Department of Neuroscience, The Scripps Research Institute, Jupiter, FL 33458, USA
| | - Enikö A Kramár
- Department of Anatomy and Neurobiology, University of California, Irvine, Irvine, CA 92797, USA
| | - Camilo Rojas
- Department of Neuroscience, The Scripps Research Institute, Jupiter, FL 33458, USA
| | - Ron R Seese
- Department of Anatomy and Neurobiology, University of California, Irvine, Irvine, CA 92797, USA
| | - Alex H Babyan
- Department of Anatomy and Neurobiology, University of California, Irvine, Irvine, CA 92797, USA
| | - Yulin Shi
- Department of Anatomy and Neurobiology, University of California, Irvine, Irvine, CA 92797, USA
| | - Rocco Lucero
- Developmental Neurogenetics Laboratory, Departments of Neurology, Neuroscience, and Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Xiangmin Xu
- Department of Anatomy and Neurobiology, University of California, Irvine, Irvine, CA 92797, USA
| | - Jeffrey L Noebels
- Developmental Neurogenetics Laboratory, Departments of Neurology, Neuroscience, and Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Courtney A Miller
- Department of Neuroscience, The Scripps Research Institute, Jupiter, FL 33458, USA; Department of Metabolism and Aging, The Scripps Research Institute, Jupiter, FL 33458, USA
| | - Gary Lynch
- Department of Anatomy and Neurobiology, University of California, Irvine, Irvine, CA 92797, USA
| | - Gavin Rumbaugh
- Department of Neuroscience, The Scripps Research Institute, Jupiter, FL 33458, USA.
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20
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Cheung VCK, DeBoer C, Hanson E, Tunesi M, D'Onofrio M, Arisi I, Brandi R, Cattaneo A, Goosens KA. Gene expression changes in the motor cortex mediating motor skill learning. PLoS One 2013; 8:e61496. [PMID: 23637843 PMCID: PMC3634858 DOI: 10.1371/journal.pone.0061496] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2012] [Accepted: 03/08/2013] [Indexed: 12/11/2022] Open
Abstract
The primary motor cortex (M1) supports motor skill learning, yet little is known about the genes that contribute to motor cortical plasticity. Such knowledge could identify candidate molecules whose targeting might enable a new understanding of motor cortical functions, and provide new drug targets for the treatment of diseases which impair motor function, such as ischemic stroke. Here, we assess changes in the motor-cortical transcriptome across different stages of motor skill acquisition. Adult rats were trained on a gradually acquired appetitive reach and grasp task that required different strategies for successful pellet retrieval, or a sham version of the task in which the rats received pellet reward without needing to develop the reach and grasp skill. Tissue was harvested from the forelimb motor-cortical area either before training commenced, prior to the initial rise in task performance, or at peak performance. Differential classes of gene expression were observed at the time point immediately preceding motor task improvement. Functional clustering revealed that gene expression changes were related to the synapse, development, intracellular signaling, and the fibroblast growth factor (FGF) family, with many modulated genes known to regulate synaptic plasticity, synaptogenesis, and cytoskeletal dynamics. The modulated expression of synaptic genes likely reflects ongoing network reorganization from commencement of training till the point of task improvement, suggesting that motor performance improves only after sufficient modifications in the cortical circuitry have accumulated. The regulated FGF-related genes may together contribute to M1 remodeling through their roles in synaptic growth and maturation.
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Affiliation(s)
- Vincent C. K. Cheung
- McGovern Institute for Brain Research, and Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States of America
- * E-mail: (VCKC); (KAG)
| | - Caroline DeBoer
- McGovern Institute for Brain Research, and Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States of America
| | - Elizabeth Hanson
- McGovern Institute for Brain Research, and Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States of America
| | - Marta Tunesi
- Department of Chemistry, Materials and Chemical Engineering ‘Giulio Natta’, Politecnico di Milano, Milan, Italy
| | - Mara D'Onofrio
- European Brain Research Institute ‘Rita Levi-Montalcini’, Rome, Italy
| | - Ivan Arisi
- European Brain Research Institute ‘Rita Levi-Montalcini’, Rome, Italy
| | - Rossella Brandi
- European Brain Research Institute ‘Rita Levi-Montalcini’, Rome, Italy
| | - Antonino Cattaneo
- European Brain Research Institute ‘Rita Levi-Montalcini’, Rome, Italy
| | - Ki A. Goosens
- McGovern Institute for Brain Research, and Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States of America
- * E-mail: (VCKC); (KAG)
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21
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Clement JP, Aceti M, Creson TK, Ozkan ED, Shi Y, Reish NJ, Almonte AG, Miller BH, Wiltgen BJ, Miller CA, Xu X, Rumbaugh G. Pathogenic SYNGAP1 mutations impair cognitive development by disrupting maturation of dendritic spine synapses. Cell 2013; 151:709-723. [PMID: 23141534 DOI: 10.1016/j.cell.2012.08.045] [Citation(s) in RCA: 263] [Impact Index Per Article: 23.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2012] [Revised: 07/21/2012] [Accepted: 08/20/2012] [Indexed: 01/28/2023]
Abstract
Mutations that cause intellectual disability (ID) and autism spectrum disorder (ASD) are commonly found in genes that encode for synaptic proteins. However, it remains unclear how mutations that disrupt synapse function impact intellectual ability. In the SYNGAP1 mouse model of ID/ASD, we found that dendritic spine synapses develop prematurely during the early postnatal period. Premature spine maturation dramatically enhanced excitability in the developing hippocampus, which corresponded with the emergence of behavioral abnormalities. Inducing SYNGAP1 mutations after critical developmental windows closed had minimal impact on spine synapse function, whereas repairing these pathogenic mutations in adulthood did not improve behavior and cognition. These data demonstrate that SynGAP protein acts as a critical developmental repressor of neural excitability that promotes the development of life-long cognitive abilities. We propose that the pace of dendritic spine synapse maturation in early life is a critical determinant of normal intellectual development.
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Affiliation(s)
- James P Clement
- Department of Neuroscience, The Scripps Research Institute, Jupiter, FL 33458, USA
| | - Massimiliano Aceti
- Department of Neuroscience, The Scripps Research Institute, Jupiter, FL 33458, USA
| | - Thomas K Creson
- Department of Neuroscience, The Scripps Research Institute, Jupiter, FL 33458, USA
| | - Emin D Ozkan
- Department of Neuroscience, The Scripps Research Institute, Jupiter, FL 33458, USA
| | - Yulin Shi
- Department of Anatomy and Neurobiology, University of California, Irvine, CA 92697, USA
| | - Nicholas J Reish
- Department of Neurobiology, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - Antoine G Almonte
- Department of Neurobiology, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - Brooke H Miller
- Department of Neuroscience, The Scripps Research Institute, Jupiter, FL 33458, USA
| | - Brian J Wiltgen
- Department of Psychology, University of Virginia, Charlottesville, VA 22904, USA
| | - Courtney A Miller
- Department of Neuroscience, The Scripps Research Institute, Jupiter, FL 33458, USA; Department of Metabolism and Aging, The Scripps Research Institute, Jupiter, FL 33458, USA
| | - Xiangmin Xu
- Department of Anatomy and Neurobiology, University of California, Irvine, CA 92697, USA
| | - Gavin Rumbaugh
- Department of Neuroscience, The Scripps Research Institute, Jupiter, FL 33458, USA.
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22
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SynGAP moves out of the core of the postsynaptic density upon depolarization. Neuroscience 2011; 192:132-9. [PMID: 21736925 DOI: 10.1016/j.neuroscience.2011.06.061] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2011] [Revised: 05/29/2011] [Accepted: 06/21/2011] [Indexed: 12/25/2022]
Abstract
SynGAP is a Ras GTPase activating protein present at the postsynaptic density (PSD) in quantities matching those of the core scaffold protein PSD-95. SynGAP is reported to inhibit synaptic accumulation of AMPA receptors. Here, we characterize by immunogold electron microscopy the distribution of SynGAP at the PSD under basal and depolarizing conditions in rat hippocampal neuronal cultures. The PSD core, extending up to 40 nm from the postsynaptic membrane, typically shows label for SynGAP, while half of the synapses exhibit additional labeling in a zone 40-120 nm from the postsynaptic membrane. Upon depolarization with high K(+), labeling for SynGAP significantly decreases at the core of the PSD and concomitantly increases at the 40-120 nm zone. Under the same depolarization conditions, label for PSD-95, the presumed binding partner of SynGAP, does not change its localization at the PSD. Depolarization-induced redistribution of SynGAP is reversible and also occurs upon application of N-methyl-d-aspartic acid (NMDA). Activity-induced movement of SynGAP could vacate sites in the PSD core allowing other elements to bind to these sites, such as transmembrane AMPA receptor regulatory proteins (TARPs), and simultaneously facilitate access of SynGAP to CaMKII and Ras, elements of a regulatory cascade.
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23
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Komoike Y, Shimojima K, Liang JS, Fujii H, Maegaki Y, Osawa M, Fujii S, Higashinakagawa T, Yamamoto T. A functional analysis of GABARAP on 17p13.1 by knockdown zebrafish. J Hum Genet 2010; 55:155-62. [PMID: 20111057 DOI: 10.1038/jhg.2010.1] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Array-based comparative genomic hybridization identified a 2.3-Mb microdeletion of 17p13.2p13.1 in a boy presenting with moderate mental retardation, intractable epilepsy and dysmorphic features. This deletion region was overlapped with the previously proposed shortest region overlapped for microdeletion of 17p13.1 in patients with mental retardation, microcephaly, microretrognathia and abnormal magnetic resonance imaging (MRI) findings of cerebral white matter, in which at least 17 known genes are included. Among them, DLG4/PSD95, GPS2, GABARAP and KCTD11 have a function in neuronal development. Because of the functional importance, we paid attention to DLG4/PSD95 and GABARAP, and analyzed zebrafish in which the zebrafish homolog of human DLG4/PSD95 and GABARAP was knocked down and found that gabarap knockdown resulted in small head and hypoplastic mandible. This finding would be similar to the common findings of the patients with 17p13.1 deletions. Although there were no pathogenic mutations in DLG4/PSD95 or GABARAP in a cohort study with 142 patients with idiopathic developmental delay with/without epilepsy, further studies would be required for genes included in this region.
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Affiliation(s)
- Yuta Komoike
- International Research and Educational Institute for Integrated Medical Sciences (IREIIMS), Tokyo Women's Medical University, Tokyo, Japan
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24
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Guo X, Hamilton P, Reish NJ, Sweatt JD, Miller CA, Rumbaugh G. Reduced expression of the NMDA receptor-interacting protein SynGAP causes behavioral abnormalities that model symptoms of Schizophrenia. Neuropsychopharmacology 2009; 34:1659-72. [PMID: 19145222 PMCID: PMC3690772 DOI: 10.1038/npp.2008.223] [Citation(s) in RCA: 90] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Abnormal function of NMDA receptors is believed to be a contributing factor to the pathophysiology of schizophrenia. NMDAR subunits and postsynaptic-interacting proteins of these channels are abnormally expressed in some patients with this illness. In mice, reduced NMDAR expression leads to behaviors analogous to symptoms of schizophrenia, but reports of animals with mutations in core postsynaptic density proteins having similar a phenotype have yet to be reported. Here we show that reduced expression of the neuronal RasGAP and NMDAR-associated protein, SynGAP, results in abnormal behaviors strikingly similar to that reported in mice with reduced NMDAR function. SynGAP mutant mice exhibited nonhabituating and persistent hyperactivity that was ameliorated by the antipsychotic clozapine. An NMDAR antagonist, MK-801, induced hyperactivity in normal mice but SynGAP mutants were less responsive, suggesting that NMDAR hypofunction contributes to this behavioral abnormality. SynGAP mutants exhibited enhanced startle reactivity and impaired sensory-motor gating. These mice also displayed a complete lack of social memory and a propensity toward social isolation. Finally, SynGAP mutants had deficits in cued fear conditioning and working memory, indicating abnormal function of circuits that control emotion and choice. Our results demonstrate that SynGAP mutant mice have gross neurological deficits similar to other mouse models of schizophrenia. Because SynGAP interacts with NMDARs, and the signaling activity of this protein is regulated by these channels, our data in dicate that SynGAP lies downstream of NMDARs and is a required intermediate for normal neural circuit function and behavior. Taken together, these data support the idea that schizophrenia may arise from abnormal signaling pathways that are mediated by NMDA receptors.
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Affiliation(s)
- Xiaochuan Guo
- Department of Neurobiology and Evelyn F. McKnight Brain Institute, The University of Alabama at Birmingham, Birmingham, Alabama 35294
| | | | - Nicholas J. Reish
- Department of Neurobiology and Evelyn F. McKnight Brain Institute, The University of Alabama at Birmingham, Birmingham, Alabama 35294,UAB Medical Scientist Training Program (MSTP)
| | - J. David Sweatt
- Department of Neurobiology and Evelyn F. McKnight Brain Institute, The University of Alabama at Birmingham, Birmingham, Alabama 35294
| | - Courtney A. Miller
- Department of Neurobiology and Evelyn F. McKnight Brain Institute, The University of Alabama at Birmingham, Birmingham, Alabama 35294
| | - Gavin Rumbaugh
- Department of Neurobiology and Evelyn F. McKnight Brain Institute, The University of Alabama at Birmingham, Birmingham, Alabama 35294,UAB Summer Program in Neuroscience (SPIN),Correspondence: Gavin Rumbaugh,
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25
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Moon IS, Sakagami H, Nakayama J, Suzuki T. Differential distribution of synGAP alpha1 and synGAP beta isoforms in rat neurons. Brain Res 2008; 1241:62-75. [PMID: 18824155 DOI: 10.1016/j.brainres.2008.09.033] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2008] [Revised: 08/25/2008] [Accepted: 09/09/2008] [Indexed: 10/21/2022]
Abstract
The synaptic Ras-GTPase activating protein synGAP is a brain-specific protein of approximately 130 kDa and is a negative regulator of Ras. We previously reported 5 C-terminal isoforms of synGAP (alpha1, alpha2, beta1/2, beta 3/4 and gamma) [Li et al., 2001, J. Biol. Chem. 276: 21417-21424]. In this study, we investigated the expression profiles of the two major isoforms, synGAP alpha1 and synGAP beta, in the adult rat brain and cultured neurons of the rat hippocampus. Examination of pepsin-pretreated brain sections demonstrated that both isoforms were expressed mainly in the forebrain structures, which suggests their association with postsynaptic density. The distribution of the synGAP alpha1 and beta (beta1-4) isoforms in the adult rat brain was clearly different in cerebellum, hippocampus, cerebral cortex, septum and olfactory bulb. In particular, synGAP alpha1 was specifically localized to the cerebellar glomeruli, dense synaptic sites. From the analysis using cultured neurons, unique expression of synGAP beta was found in a neuron with a sea urchin-like morphology, possibly a star pyramidal neuron, in which the synGAP beta expression was relatively high, in particular, at the distal part of its processes. SynGAP alpha1 was mostly or specifically localized to excitatory postsynaptic sites, whereas synGAP beta was present at both excitatory and inhibitory postsynaptic sites. Finally, there are more non-synaptic clusters in dendrites in the case of synGAP beta than synGAP alpha1. Thus, the two synGAP isoforms, alpha1 and beta, distribute differently in neuronal cells and the brain.
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Affiliation(s)
- Il Soo Moon
- Department of Anatomy, College of Medicine, Dongguk University, Gyeongju 780-714, Republic of Korea
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26
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Avery AW, Figueroa C, Vojtek AB. UNC-51-like kinase regulation of fibroblast growth factor receptor substrate 2/3. Cell Signal 2007; 19:177-84. [PMID: 16887332 DOI: 10.1016/j.cellsig.2006.06.003] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2006] [Accepted: 06/15/2006] [Indexed: 11/20/2022]
Abstract
UNC-51-like kinases (ULK) are members of an evolutionarily conserved sub-family of ubiquitously expressed serine/threonine-specific protein kinases. Here we report that fibroblast growth factor receptor substrate (FRS) 2/3 are novel ULK2 carboxy-terminal domain interacting proteins. FRS2/3 are homologs that function as adaptor proteins to mediate signaling of multiple receptor tyrosine kinases. ULK2 interacts with the phospho-tyrosine binding (PTB) domain of FRS2/3. We demonstrate that siRNA targeting ULK2 in mouse P19 cells results in elevated FGFR1 mediated FRS3 and SHP2 tyrosyl phosphorylation. In addition, RNAi-mediated decrease in ULK2 causes increased interaction between FGFR1 and FRS3. ULK2 phosphorylates FRS2/3 in vitro, suggesting that ULK2 mediated phosphorylation may be a mechanism of FRS2/3 regulation. The data presented support a model in which ULK2, by interaction with FRS2/3 and inhibition of SynGAP, functions to negatively regulate tyrosyl phosphorylation of signaling proteins downstream of FGFR1.
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Affiliation(s)
- Adam W Avery
- Department of Biological Chemistry, 3323 MSRB III Box 0606, University of Michigan, Ann Arbor, MI 48109-0606, USA
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27
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Ito-Ishida A, Kakegawa W, Yuzaki M. ERK1/2 but not p38 MAP kinase is essential for the long-term depression in mouse cerebellar slices. Eur J Neurosci 2006; 24:1617-22. [PMID: 17004925 DOI: 10.1111/j.1460-9568.2006.05055.x] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Mitogen-activated protein kinase (MAPK) cascade is essential for synaptic plasticity and learning. In the hippocampus, three different MAPK subfamilies, extracellular signal-regulated kinase 1/2 (ERK1/2), p38 MAPK and c-Jun NH2-terminal protein kinase (JNK), selectively regulate activity-dependent glutamate receptor trafficking during long-term potentiation (LTP), long-term depression (LTD), and depotentiation after LTP, respectively. Although LTP and LTD at cerebellar parallel fibre (PF)-Purkinje cell synapses are thought to be controlled by glutamate receptor trafficking, the involvement of MAPK subfamilies has not been systemically studied in cerebellar slice preparations. To clarify the role of the MAPK cascade in cerebellar LTD, we performed biochemical and electrophysiological analyses using ICR mouse cerebellar slices. Immunoblot analyses using phosphorylation-specific antibodies for MAPKs revealed that among the three MAPKs, ERK1/2 was specifically activated by phorbol ester, which could induce LTD in cerebellar slices. In addition, U0126, a specific inhibitor of the MAPK kinase-ERK1/2 pathway, abrogated the induction of LTD in cerebellar slices, whereas SB203580 and SP600125, specific inhibitors of p38 MAPK and JNK, respectively, had no effect. Although metabotropic glutamate receptor 1 (mGluR1) has been suggested as a possible downstream target of ERK1/2 in cell-culture preparations, mGluR1-activated slow excitatory postsynaptic currents (EPSCs) were not affected by U0126 treatment in slices. These findings indicate that unlike hippocampal LTD mediated by p38 MAPK, glutamate receptor trafficking during cerebellar LTD was regulated by a distinct mechanism involving ERK1/2 in slice preparations.
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Affiliation(s)
- Aya Ito-Ishida
- Department of Physiology, School of Medicine, Keio University, 35 Shinano-machi, Shinjuku-ku, Tokyo 160-8582, Tokyo 160-8582, Japan
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28
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Anderson CNG, Grant SGN. High throughput protein expression screening in the nervous system--needs and limitations. J Physiol 2006; 575:367-72. [PMID: 16793899 PMCID: PMC1819445 DOI: 10.1113/jphysiol.2006.113795] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
The cellular complexity of the brain (some estimate that there are up to 10(3) different cell types) is exceeded by the synaptic complexity, with each of the approximately 10(11) neurons in the brain having around 10(3)-10(4) synapses. Proteomic studies of the synapse have revealed that the postsynaptic density is the most complex multiprotein structure yet identified, with approximately 10(3) different proteins. Such studies, however, use brain tissue with many different regions and therefore different cell types, and there is clear potential for heterogeneity of protein content at different synapses within and between brain regions. Although large-scale mRNA-based assays are in progress to map this sort of complexity at the cellular level, and indeed all brain-expressed genes, analysis of protein distribution (at synapses and other structures) is still in the very early stages. We review existing large-scale protein expression studies and the specific technical obstacles that need to be overcome before applying the scaling used in nucleic acid based approaches.
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Affiliation(s)
- Chris N G Anderson
- Genes to Cognition programme, Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridgeshire CB10 1SA, UK
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29
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Barnett MW, Watson RF, Vitalis T, Porter K, Komiyama NH, Stoney PN, Gillingwater TH, Grant SGN, Kind PC. Synaptic Ras GTPase activating protein regulates pattern formation in the trigeminal system of mice. J Neurosci 2006; 26:1355-65. [PMID: 16452659 PMCID: PMC6675506 DOI: 10.1523/jneurosci.3164-05.2006] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
The development of ordered connections or "maps" within the nervous system is a common feature of sensory systems and is crucial for their normal function. NMDA receptors are known to play a key role in the formation of these maps; however, the intracellular signaling pathways that mediate the effects of glutamate are poorly understood. Here, we demonstrate that SynGAP, a synaptic Ras GTPase activating protein, is essential for the anatomical development of whisker-related patterns in the developing somatosensory pathways in rodent forebrain. Mice lacking SynGAP show only partial segregation of barreloids in the thalamus, and thalamocortical axons segregate into rows but do not form whisker-related patches. In cortex, layer 4 cells do not aggregate to form barrels. In Syngap(+/-) animals, barreloids develop normally, and thalamocortical afferents segregate in layer 4, but cell segregation is retarded. SynGAP is not necessary for the development of whisker-related patterns in the brainstem. Immunoelectron microscopy for SynGAP from layer 4 revealed a postsynaptic localization with labeling in developing postsynaptic densities (PSDs). Biochemically, SynGAP associates with the PSD in a PSD-95-independent manner, and Psd-95(-/-) animals develop normal barrels. These data demonstrate an essential role for SynGAP signaling in the activity-dependent development of whisker-related maps selectively in forebrain structures indicating that the intracellular pathways by which NMDA receptor activation mediates map formation differ between brain regions and developmental stage.
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Affiliation(s)
- Mark W Barnett
- Centre for Integrative Physiology, University of Edinburgh, Edinburgh EH8 9XD, United Kingdom
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30
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Niciu MJ, Ma XM, El Meskini R, Ronnett GV, Mains RE, Eipper BA. Developmental changes in the expression of ATP7A during a critical period in postnatal neurodevelopment. Neuroscience 2006; 139:947-64. [PMID: 16549268 DOI: 10.1016/j.neuroscience.2006.01.044] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2005] [Revised: 01/16/2006] [Accepted: 01/26/2006] [Indexed: 11/27/2022]
Abstract
ATP7A is a P-type ATPase that transports copper from cytosol into the secretory pathway for loading onto cuproproteins or efflux. Mutations in Atp7a cause Menkes disease, a copper-deficiency disorder fatal in the postnatal period due to severe neurodegeneration. Early postnatal copper injections are known to diminish degenerative changes in some human patients and mice bearing mutations in Atp7a. In situ hybridization studies previously demonstrated that ATP7A transcripts are expressed widely in the brain. ATP7A-specific antibody was used to study the neurodevelopmental expression and localization of ATP7A protein in the mouse brain. Based on immunoblot analyses, ATP7A expression is most abundant in the early postnatal period, reaching peak levels at P4 in neocortex and cerebellum. In the developing and adult brain, ATP7A levels are greatest in the choroid plexus/ependymal cells of the lateral and third ventricles. ATP7A expression decreases in most neuronal subpopulations from birth to adulthood. In contrast, ATP7A expression increases in CA2 hippocampal pyramidal and cerebellar Purkinje neurons. ATP7A is expressed in a subset of astrocytes, microglia, oligodendrocytes, tanycytes and endothelial cells. ATP7A is largely localized to the trans-Golgi network, adopting the cell-specific and developmentally-regulated morphology of this organelle. The presence of ATP7A in the axons of postnatal, but not adult, optic nerve suggests stage-specific roles for this enzyme. In sum, the precisely-regulated neurodevelopmental expression of ATP7A correlates well with the limited therapeutic window for effective treatment of Menkes disease.
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Affiliation(s)
- M J Niciu
- University of Connecticut Health Center, Department of Neuroscience, Academic Research Building (E)-4047, 263 Farmington Avenue, Farmington, CT 06030, USA
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31
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Rockliffe N, Gawler D. Differential mechanisms of glutamate receptor regulation of SynGAP in cortical neurones. FEBS Lett 2006; 580:831-8. [PMID: 16427633 DOI: 10.1016/j.febslet.2005.12.100] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2005] [Revised: 12/05/2005] [Accepted: 12/14/2005] [Indexed: 11/22/2022]
Abstract
One prime candidate linking N-methyl-D-aspartate (NMDA) receptors to the regulation of the MAP kinase cascade is SynGAP, a negative regulator of Ras. In order to assess how a physiological stimulus can alter SynGAP activity, an appropriate whole cell system must be used and SynGAP must be specifically extracted from membranes whilst preserving the catalytic activity of the protein. Here, we have achieved this and studied the effect of NMDA/alpha-amino-3-hydroxy-5-methylisoxazole-4-propionic acid (AMPA) and kainate receptor stimulations on SynGAP activity in cortical neurones. Furthermore, we have examined the role of extracellular Ca2+, CaM kinase II and the PSD-95-NR2B subunit interaction in SynGAP activity regulation and propose a novel convergence of signalling between AMPA, kainate and NMDA receptors.
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Affiliation(s)
- Nichola Rockliffe
- The Physiological laboratory, University of Liverpool, Crown Street, Liverpool L69 3BX, UK.
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32
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Pocklington AJ, Cumiskey M, Armstrong JD, Grant SGN. The proteomes of neurotransmitter receptor complexes form modular networks with distributed functionality underlying plasticity and behaviour. Mol Syst Biol 2006; 2:2006.0023. [PMID: 16738568 PMCID: PMC1681474 DOI: 10.1038/msb4100041] [Citation(s) in RCA: 85] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2005] [Accepted: 11/22/2005] [Indexed: 12/31/2022] Open
Abstract
Neuronal synapses play fundamental roles in information processing, behaviour and disease. Neurotransmitter receptor complexes, such as the mammalian N-methyl-D-aspartate receptor complex (NRC/MASC) comprising 186 proteins, are major components of the synapse proteome. Here we investigate the organisation and function of NRC/MASC using a systems biology approach. Systematic annotation showed that the complex contained proteins implicated in a wide range of cognitive processes, synaptic plasticity and psychiatric diseases. Protein domains were evolutionarily conserved from yeast, but enriched with signalling domains associated with the emergence of multicellularity. Mapping of protein-protein interactions to create a network representation of the complex revealed that simple principles underlie the functional organisation of both proteins and their clusters, with modularity reflecting functional specialisation. The known functional roles of NRC/MASC proteins suggest the complex co-ordinates signalling to diverse effector pathways underlying neuronal plasticity. Importantly, using quantitative data from synaptic plasticity experiments, our model correctly predicts robustness to mutations and drug interference. These studies of synapse proteome organisation suggest that molecular networks with simple design principles underpin synaptic signalling properties with important roles in physiology, behaviour and disease.
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Affiliation(s)
| | - Mark Cumiskey
- Division of Neuroscience, Edinburgh University, Edinburgh, UK
- Wellcome Trust Sanger Institute, Cambridge, UK
| | | | - Seth G N Grant
- Division of Neuroscience, Edinburgh University, Edinburgh, UK
- Wellcome Trust Sanger Institute, Cambridge, UK
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Fallin MD, Lasseter VK, Avramopoulos D, Nicodemus KK, Wolyniec PS, McGrath JA, Steel G, Nestadt G, Liang KY, Huganir RL, Valle D, Pulver AE. Bipolar I disorder and schizophrenia: a 440-single-nucleotide polymorphism screen of 64 candidate genes among Ashkenazi Jewish case-parent trios. Am J Hum Genet 2005; 77:918-36. [PMID: 16380905 PMCID: PMC1285177 DOI: 10.1086/497703] [Citation(s) in RCA: 308] [Impact Index Per Article: 16.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2005] [Accepted: 08/25/2005] [Indexed: 12/11/2022] Open
Abstract
Bipolar, schizophrenia, and schizoaffective disorders are common, highly heritable psychiatric disorders, for which familial coaggregation, as well as epidemiological and genetic evidence, suggests overlapping etiologies. No definitive susceptibility genes have yet been identified for any of these disorders. Genetic heterogeneity, combined with phenotypic imprecision and poor marker coverage, has contributed to the difficulty in defining risk variants. We focused on families of Ashkenazi Jewish descent, to reduce genetic heterogeneity, and, as a precursor to genomewide association studies, we undertook a single-nucleotide polymorphism (SNP) genotyping screen of 64 candidate genes (440 SNPs) chosen on the basis of previous linkage or of association and/or biological relevance. We genotyped an average of 6.9 SNPs per gene, with an average density of 1 SNP per 11.9 kb in 323 bipolar I disorder and 274 schizophrenia or schizoaffective Ashkenazi case-parent trios. Using single-SNP and haplotype-based transmission/disequilibrium tests, we ranked genes on the basis of strength of association (P<.01). Six genes (DAO, GRM3, GRM4, GRIN2B, IL2RB, and TUBA8) met this criterion for bipolar I disorder; only DAO has been previously associated with bipolar disorder. Six genes (RGS4, SCA1, GRM4, DPYSL2, NOS1, and GRID1) met this criterion for schizophrenia or schizoaffective disorder; five replicate previous associations, and one, GRID1, shows a novel association with schizophrenia. In addition, six genes (DPYSL2, DTNBP1, G30/G72, GRID1, GRM4, and NOS1) showed overlapping suggestive evidence of association in both disorders. These results may help to prioritize candidate genes for future study from among the many suspected/proposed for schizophrenia and bipolar disorders. They provide further support for shared genetic susceptibility between these two disorders that involve glutamate-signaling pathways.
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Affiliation(s)
- M Daniele Fallin
- Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD 21231, USA
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Grant SGN, Marshall MC, Page KL, Cumiskey MA, Armstrong JD. Synapse proteomics of multiprotein complexes: en route from genes to nervous system diseases. Hum Mol Genet 2005; 14 Spec No. 2:R225-34. [PMID: 16150739 DOI: 10.1093/hmg/ddi330] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Proteomic experiments have produced a draft profile of the overall molecular composition of the mammalian neuronal synapse. It appears that synapses have over 1000 protein components and the mapping of their interactions, organization and functions will lead to a global view of the role of synapses in physiology and disease. A major functional subcomponent of the synaptic machinery is a multiprotein complex of glutamate receptors and adhesion proteins with associated adaptor and signalling enzymes totally 185 proteins known as the N-methyl-d-aspartate receptor complex/MAGUK associated signalling complex (NRC/MASC). Here, we review the proteomic studies and functions of NRC/MASC and specifically report on the role of its component genes in human diseases. Using a systematic literature search protocol, we identified reports of mutations or polymorphisms in 47 genes associated with 183 disorders, of which 54 were nervous system disorders. A similar number of genes are important in mouse synaptic plasticity and behaviour, where the NRC/MASC acts as a signalling complex with multiple functions provided by its individual protein components and their interactions. The individual gene mutations suggest not only an important role for the NRC/MASC in human diseases but that these diseases may be functionally connected by their common link to the NRC/MASC. The NRC/MASC is a rich source of genetic variation and provides a platform for understanding relationships of disease phenotype amenable to systematic studies such as the Genes to Cognition research consortium (www.genes2cognition.org) that links human and mouse genetics with proteomic studies.
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Affiliation(s)
- Seth G N Grant
- Wellcome Trust Sanger Institute, Hinxton, Cambridgeshire CB10 1SA, UK
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Bence M, Arbuckle MI, Dickson KS, Grant SGN. Analyses of murine postsynaptic density-95 identify novel isoforms and potential translational control elements. ACTA ACUST UNITED AC 2005; 133:143-52. [PMID: 15661374 DOI: 10.1016/j.molbrainres.2004.09.024] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/30/2004] [Indexed: 10/26/2022]
Abstract
Postsynaptic density-95 (PSD-95) is an evolutionarily conserved synaptic adaptor protein that is known to bind many proteins including the NMDA receptor. This observation has implicated it in many NMDA receptor-dependent processes including spatial learning and synaptic plasticity. We have cloned and characterised the murine PSD-95 gene. In addition, we have identified two previously uncharacterised splice variants of the major murine PSD-95 transcript (PSD-95alpha): PSD-95alpha-2b results from an extension of exon 2 and PSD-95alpha-Delta18 from the temporal exclusion of exon 18. The presence of PSD-95alpha-2b sequences in other PSD-95 family members implicates this peptide stretch as functionally significant. Another potential transcript (PSD-95gamma) was also identified based on examination of EST databases. Immunoprecipitation assays demonstrate that proteins corresponding in size to PSD-95alpha-Delta18 and PSD-95gamma interact with the NMDA receptor, suggesting an important biological role for these isoforms. Finally, we have performed bioinformatics analyses of the PSD-95 mRNA untranslated regions, identifying multiple translational control elements that suggest protein production could be regulated post-transcriptionally. The variety of mRNA isoforms and regulatory elements identified provides for a high degree of diversity in the structure and function of PSD-95 proteins.
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Affiliation(s)
- Matthew Bence
- Division of Neuroscience, University of Edinburgh, Edinburgh EH8 9JZ, UK
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