1
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Held RG, Liang J, Brunger AT. Nanoscale architecture of synaptic vesicles and scaffolding complexes revealed by cryo-electron tomography. Proc Natl Acad Sci U S A 2024; 121:e2403136121. [PMID: 38923992 PMCID: PMC11228483 DOI: 10.1073/pnas.2403136121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2024] [Accepted: 05/16/2024] [Indexed: 06/28/2024] Open
Abstract
The spatial distribution of proteins and their arrangement within the cellular ultrastructure regulates the opening of α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptors in response to glutamate release at the synapse. Fluorescence microscopy imaging revealed that the postsynaptic density (PSD) and scaffolding proteins in the presynaptic active zone (AZ) align across the synapse to form a trans-synaptic "nanocolumn," but the relation to synaptic vesicle release sites is uncertain. Here, we employ focused-ion beam (FIB) milling and cryoelectron tomography to image synapses under near-native conditions. Improved image contrast, enabled by FIB milling, allows simultaneous visualization of supramolecular nanoclusters within the AZ and PSD and synaptic vesicles. Surprisingly, membrane-proximal synaptic vesicles, which fuse to release glutamate, are not preferentially aligned with AZ or PSD nanoclusters. These synaptic vesicles are linked to the membrane by peripheral protein densities, often consistent in size and shape with Munc13, as well as globular densities bridging the synaptic vesicle and plasma membrane, consistent with prefusion complexes of SNAREs, synaptotagmins, and complexin. Monte Carlo simulations of synaptic transmission events using biorealistic models guided by our tomograms predict that clustering AMPARs within PSD nanoclusters increases the variability of the postsynaptic response but not its average amplitude. Together, our data support a model in which synaptic strength is tuned at the level of single vesicles by the spatial relationship between scaffolding nanoclusters and single synaptic vesicle fusion sites.
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Affiliation(s)
- Richard G. Held
- Department of Molecular and Cellular Physiology, Stanford University, Stanford, CA94305
- Department of Neurology and Neurological Sciences, Stanford University, Stanford, CA94305
- Department of Structural Biology, Stanford University, Stanford, CA94305
- Department of Photon Science, Stanford University, Stanford, CA94305
- HHMI, Stanford University, Stanford, CA94305
| | - Jiahao Liang
- Department of Molecular and Cellular Physiology, Stanford University, Stanford, CA94305
- Department of Neurology and Neurological Sciences, Stanford University, Stanford, CA94305
- Department of Structural Biology, Stanford University, Stanford, CA94305
- Department of Photon Science, Stanford University, Stanford, CA94305
- HHMI, Stanford University, Stanford, CA94305
| | - Axel T. Brunger
- Department of Molecular and Cellular Physiology, Stanford University, Stanford, CA94305
- Department of Neurology and Neurological Sciences, Stanford University, Stanford, CA94305
- Department of Structural Biology, Stanford University, Stanford, CA94305
- Department of Photon Science, Stanford University, Stanford, CA94305
- HHMI, Stanford University, Stanford, CA94305
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2
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Kim S, Jang G, Kim H, Lim D, Han KA, Um JW, Ko J. MDGAs perform activity-dependent synapse type-specific suppression via distinct extracellular mechanisms. Proc Natl Acad Sci U S A 2024; 121:e2322978121. [PMID: 38900791 PMCID: PMC11214077 DOI: 10.1073/pnas.2322978121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2023] [Accepted: 05/15/2024] [Indexed: 06/22/2024] Open
Abstract
MDGA (MAM domain containing glycosylphosphatidylinositol anchor) family proteins were previously identified as synaptic suppressive factors. However, various genetic manipulations have yielded often irreconcilable results, precluding precise evaluation of MDGA functions. Here, we found that, in cultured hippocampal neurons, conditional deletion of MDGA1 and MDGA2 causes specific alterations in synapse numbers, basal synaptic transmission, and synaptic strength at GABAergic and glutamatergic synapses, respectively. Moreover, MDGA2 deletion enhanced both N-methyl-D-aspartate (NMDA) receptor- and α-amino-3-hydroxy-5-methylisoxazole-4-propionic acid (AMPA) receptor-mediated postsynaptic responses. Strikingly, ablation of both MDGA1 and MDGA2 abolished the effect of deleting individual MDGAs that is abrogated by chronic blockade of synaptic activity. Molecular replacement experiments further showed that MDGA1 requires the meprin/A5 protein/PTPmu (MAM) domain, whereas MDGA2 acts via neuroligin-dependent and/or MAM domain-dependent pathways to regulate distinct postsynaptic properties. Together, our data demonstrate that MDGA paralogs act as unique negative regulators of activity-dependent postsynaptic organization at distinct synapse types, and cooperatively contribute to adjustment of excitation-inhibition balance.
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Affiliation(s)
- Seungjoon Kim
- Department of Brain Sciences, Daegu Gyeongbuk Institute of Science and Technology, Daegu42988, Korea
- Center for Synapse Diversity and Specificity, Daegu Gyeongbuk Institute of Science and Technology, Daegu42988, Korea
| | - Gyubin Jang
- Department of Brain Sciences, Daegu Gyeongbuk Institute of Science and Technology, Daegu42988, Korea
- Center for Synapse Diversity and Specificity, Daegu Gyeongbuk Institute of Science and Technology, Daegu42988, Korea
| | - Hyeonho Kim
- Department of Brain Sciences, Daegu Gyeongbuk Institute of Science and Technology, Daegu42988, Korea
- Center for Synapse Diversity and Specificity, Daegu Gyeongbuk Institute of Science and Technology, Daegu42988, Korea
| | - Dongseok Lim
- Department of Brain Sciences, Daegu Gyeongbuk Institute of Science and Technology, Daegu42988, Korea
| | - Kyung Ah Han
- Department of Brain Sciences, Daegu Gyeongbuk Institute of Science and Technology, Daegu42988, Korea
- Center for Synapse Diversity and Specificity, Daegu Gyeongbuk Institute of Science and Technology, Daegu42988, Korea
| | - Ji Won Um
- Department of Brain Sciences, Daegu Gyeongbuk Institute of Science and Technology, Daegu42988, Korea
- Center for Synapse Diversity and Specificity, Daegu Gyeongbuk Institute of Science and Technology, Daegu42988, Korea
| | - Jaewon Ko
- Department of Brain Sciences, Daegu Gyeongbuk Institute of Science and Technology, Daegu42988, Korea
- Center for Synapse Diversity and Specificity, Daegu Gyeongbuk Institute of Science and Technology, Daegu42988, Korea
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3
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Wang L, Mirabella VR, Dai R, Su X, Xu R, Jadali A, Bernabucci M, Singh I, Chen Y, Tian J, Jiang P, Kwan KY, Pak C, Liu C, Comoletti D, Hart RP, Chen C, Südhof TC, Pang ZP. Analyses of the autism-associated neuroligin-3 R451C mutation in human neurons reveal a gain-of-function synaptic mechanism. Mol Psychiatry 2024; 29:1620-1635. [PMID: 36280753 PMCID: PMC10123180 DOI: 10.1038/s41380-022-01834-x] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/12/2021] [Revised: 10/04/2022] [Accepted: 10/10/2022] [Indexed: 12/11/2022]
Abstract
Mutations in many synaptic genes are associated with autism spectrum disorders (ASD), suggesting that synaptic dysfunction is a key driver of ASD pathogenesis. Among these mutations, the R451C substitution in the NLGN3 gene that encodes the postsynaptic adhesion molecule Neuroligin-3 is noteworthy because it was the first specific mutation linked to ASDs. In mice, the corresponding Nlgn3 R451C-knockin mutation recapitulates social interaction deficits of ASD patients and produces synaptic abnormalities, but the impact of the NLGN3 R451C mutation on human neurons has not been investigated. Here, we generated human knockin neurons with the NLGN3 R451C and NLGN3 null mutations. Strikingly, analyses of NLGN3 R451C-mutant neurons revealed that the R451C mutation decreased NLGN3 protein levels but enhanced the strength of excitatory synapses without affecting inhibitory synapses; meanwhile NLGN3 knockout neurons showed reduction in excitatory synaptic strengths. Moreover, overexpression of NLGN3 R451C recapitulated the synaptic enhancement in human neurons. Notably, the augmentation of excitatory transmission was confirmed in vivo with human neurons transplanted into mouse forebrain. Using single-cell RNA-seq experiments with co-cultured excitatory and inhibitory NLGN3 R451C-mutant neurons, we identified differentially expressed genes in relatively mature human neurons corresponding to synaptic gene expression networks. Moreover, gene ontology and enrichment analyses revealed convergent gene networks associated with ASDs and other mental disorders. Our findings suggest that the NLGN3 R451C mutation induces a gain-of-function enhancement in excitatory synaptic transmission that may contribute to the pathophysiology of ASD.
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Affiliation(s)
- Le Wang
- Child Health Institute of New Jersey and Department of Neuroscience and Cell Biology, Robert Wood Johnson Medical School, Rutgers University, New Brunswick, NJ, 08901, USA
- Center for Medical Genetics & Hunan Key Laboratory of Medical Genetics, School of Life Sciences, and Department of Psychiatry, The Second Xiangya Hospital, Central South University, 410008, Changsha, China
| | - Vincent R Mirabella
- Child Health Institute of New Jersey and Department of Neuroscience and Cell Biology, Robert Wood Johnson Medical School, Rutgers University, New Brunswick, NJ, 08901, USA
- Department of Molecular & Cellular Physiology, Stanford University School of Medicine, Stanford, CA, 94305, USA
| | - Rujia Dai
- Department of Psychiatry, SUNY Upstate Medical University, Syracuse, NY, 13210, USA
| | - Xiao Su
- Child Health Institute of New Jersey and Department of Neuroscience and Cell Biology, Robert Wood Johnson Medical School, Rutgers University, New Brunswick, NJ, 08901, USA
| | - Ranjie Xu
- Department of Cell Biology and Neuroscience, Rutgers University, Piscataway, NJ, 08854, USA
| | - Azadeh Jadali
- Department of Cell Biology and Neuroscience, Rutgers University, Piscataway, NJ, 08854, USA
| | - Matteo Bernabucci
- Child Health Institute of New Jersey and Department of Neuroscience and Cell Biology, Robert Wood Johnson Medical School, Rutgers University, New Brunswick, NJ, 08901, USA
| | - Ishnoor Singh
- Child Health Institute of New Jersey and Department of Neuroscience and Cell Biology, Robert Wood Johnson Medical School, Rutgers University, New Brunswick, NJ, 08901, USA
| | - Yu Chen
- Center for Medical Genetics & Hunan Key Laboratory of Medical Genetics, School of Life Sciences, and Department of Psychiatry, The Second Xiangya Hospital, Central South University, 410008, Changsha, China
| | - Jianghua Tian
- Center for Medical Genetics & Hunan Key Laboratory of Medical Genetics, School of Life Sciences, and Department of Psychiatry, The Second Xiangya Hospital, Central South University, 410008, Changsha, China
| | - Peng Jiang
- Department of Cell Biology and Neuroscience, Rutgers University, Piscataway, NJ, 08854, USA
| | - Kevin Y Kwan
- Department of Cell Biology and Neuroscience, Rutgers University, Piscataway, NJ, 08854, USA
| | - ChangHui Pak
- Department of Biochemistry & Molecular Biology, University of Massachusetts, Amherst, MA, 01003, USA
| | - Chunyu Liu
- Center for Medical Genetics & Hunan Key Laboratory of Medical Genetics, School of Life Sciences, and Department of Psychiatry, The Second Xiangya Hospital, Central South University, 410008, Changsha, China
- Department of Psychiatry, SUNY Upstate Medical University, Syracuse, NY, 13210, USA
- School of Psychology, Shaanxi Normal University, 710000, Xi'an, Shaanxi, China
| | - Davide Comoletti
- Child Health Institute of New Jersey and Department of Neuroscience and Cell Biology, Robert Wood Johnson Medical School, Rutgers University, New Brunswick, NJ, 08901, USA
- School of Biological Sciences, Victoria University of Wellington, Wellington, 6012, New Zealand
| | - Ronald P Hart
- Department of Cell Biology and Neuroscience, Rutgers University, Piscataway, NJ, 08854, USA
| | - Chao Chen
- Center for Medical Genetics & Hunan Key Laboratory of Medical Genetics, School of Life Sciences, and Department of Psychiatry, The Second Xiangya Hospital, Central South University, 410008, Changsha, China.
- National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, 410008, Changsha, Hunan, China.
- Hunan Key Laboratory of Animal Models for Human Diseases, Central South University, 410008, Changsha, Hunan, China.
| | - Thomas C Südhof
- Department of Molecular & Cellular Physiology, Stanford University School of Medicine, Stanford, CA, 94305, USA.
- Howard Hughes Medical Institute, Stanford University School of Medicine, Stanford, CA, 94305, USA.
| | - Zhiping P Pang
- Child Health Institute of New Jersey and Department of Neuroscience and Cell Biology, Robert Wood Johnson Medical School, Rutgers University, New Brunswick, NJ, 08901, USA.
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4
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Weigel B, Tegethoff JF, Grieder SD, Lim B, Nagarajan B, Liu YC, Truberg J, Papageorgiou D, Adrian-Segarra JM, Schmidt LK, Kaspar J, Poisel E, Heinzelmann E, Saraswat M, Christ M, Arnold C, Ibarra IL, Campos J, Krijgsveld J, Monyer H, Zaugg JB, Acuna C, Mall M. MYT1L haploinsufficiency in human neurons and mice causes autism-associated phenotypes that can be reversed by genetic and pharmacologic intervention. Mol Psychiatry 2023; 28:2122-2135. [PMID: 36782060 PMCID: PMC10575775 DOI: 10.1038/s41380-023-01959-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/24/2022] [Revised: 12/30/2022] [Accepted: 01/11/2023] [Indexed: 02/15/2023]
Abstract
MYT1L is an autism spectrum disorder (ASD)-associated transcription factor that is expressed in virtually all neurons throughout life. How MYT1L mutations cause neurological phenotypes and whether they can be targeted remains enigmatic. Here, we examine the effects of MYT1L deficiency in human neurons and mice. Mutant mice exhibit neurodevelopmental delays with thinner cortices, behavioural phenotypes, and gene expression changes that resemble those of ASD patients. MYT1L target genes, including WNT and NOTCH, are activated upon MYT1L depletion and their chemical inhibition can rescue delayed neurogenesis in vitro. MYT1L deficiency also causes upregulation of the main cardiac sodium channel, SCN5A, and neuronal hyperactivity, which could be restored by shRNA-mediated knockdown of SCN5A or MYT1L overexpression in postmitotic neurons. Acute application of the sodium channel blocker, lamotrigine, also rescued electrophysiological defects in vitro and behaviour phenotypes in vivo. Hence, MYT1L mutation causes both developmental and postmitotic neurological defects. However, acute intervention can normalise resulting electrophysiological and behavioural phenotypes in adulthood.
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Affiliation(s)
- Bettina Weigel
- Cell Fate Engineering and Disease Modeling Group, German Cancer Research Center (DKFZ) and DKFZ-ZMBH Alliance, 69120, Heidelberg, Germany
- HITBR Hector Institute for Translational Brain Research gGmbH, 69120, Heidelberg, Germany
- Central Institute of Mental Health, Medical Faculty Mannheim, Heidelberg University, 68159, Mannheim, Germany
- Faculty of Biosciences, Heidelberg University, 69120, Heidelberg, Germany
| | - Jana F Tegethoff
- Cell Fate Engineering and Disease Modeling Group, German Cancer Research Center (DKFZ) and DKFZ-ZMBH Alliance, 69120, Heidelberg, Germany
- HITBR Hector Institute for Translational Brain Research gGmbH, 69120, Heidelberg, Germany
- Central Institute of Mental Health, Medical Faculty Mannheim, Heidelberg University, 68159, Mannheim, Germany
- Faculty of Biosciences, Heidelberg University, 69120, Heidelberg, Germany
| | - Sarah D Grieder
- Cell Fate Engineering and Disease Modeling Group, German Cancer Research Center (DKFZ) and DKFZ-ZMBH Alliance, 69120, Heidelberg, Germany
- HITBR Hector Institute for Translational Brain Research gGmbH, 69120, Heidelberg, Germany
- Central Institute of Mental Health, Medical Faculty Mannheim, Heidelberg University, 68159, Mannheim, Germany
| | - Bryce Lim
- Cell Fate Engineering and Disease Modeling Group, German Cancer Research Center (DKFZ) and DKFZ-ZMBH Alliance, 69120, Heidelberg, Germany
- HITBR Hector Institute for Translational Brain Research gGmbH, 69120, Heidelberg, Germany
- Central Institute of Mental Health, Medical Faculty Mannheim, Heidelberg University, 68159, Mannheim, Germany
- Faculty of Biosciences, Heidelberg University, 69120, Heidelberg, Germany
| | - Bhuvaneswari Nagarajan
- Cell Fate Engineering and Disease Modeling Group, German Cancer Research Center (DKFZ) and DKFZ-ZMBH Alliance, 69120, Heidelberg, Germany
- HITBR Hector Institute for Translational Brain Research gGmbH, 69120, Heidelberg, Germany
- Central Institute of Mental Health, Medical Faculty Mannheim, Heidelberg University, 68159, Mannheim, Germany
| | - Yu-Chao Liu
- Department of Clinical Neurobiology, University Hospital Heidelberg and DKFZ, Heidelberg, Germany
| | - Jule Truberg
- Cell Fate Engineering and Disease Modeling Group, German Cancer Research Center (DKFZ) and DKFZ-ZMBH Alliance, 69120, Heidelberg, Germany
- HITBR Hector Institute for Translational Brain Research gGmbH, 69120, Heidelberg, Germany
- Central Institute of Mental Health, Medical Faculty Mannheim, Heidelberg University, 68159, Mannheim, Germany
- Faculty of Biosciences, Heidelberg University, 69120, Heidelberg, Germany
| | - Dimitris Papageorgiou
- Division of Proteomics of Stem Cells and Cancer, German Cancer Research Center (DKFZ), 69120, Heidelberg, Germany
- Medical Faculty, Heidelberg University, 69120, Heidelberg, Germany
| | - Juan M Adrian-Segarra
- Cell Fate Engineering and Disease Modeling Group, German Cancer Research Center (DKFZ) and DKFZ-ZMBH Alliance, 69120, Heidelberg, Germany
- HITBR Hector Institute for Translational Brain Research gGmbH, 69120, Heidelberg, Germany
- Central Institute of Mental Health, Medical Faculty Mannheim, Heidelberg University, 68159, Mannheim, Germany
| | - Laura K Schmidt
- Cell Fate Engineering and Disease Modeling Group, German Cancer Research Center (DKFZ) and DKFZ-ZMBH Alliance, 69120, Heidelberg, Germany
- HITBR Hector Institute for Translational Brain Research gGmbH, 69120, Heidelberg, Germany
- Central Institute of Mental Health, Medical Faculty Mannheim, Heidelberg University, 68159, Mannheim, Germany
| | - Janina Kaspar
- Cell Fate Engineering and Disease Modeling Group, German Cancer Research Center (DKFZ) and DKFZ-ZMBH Alliance, 69120, Heidelberg, Germany
- HITBR Hector Institute for Translational Brain Research gGmbH, 69120, Heidelberg, Germany
- Central Institute of Mental Health, Medical Faculty Mannheim, Heidelberg University, 68159, Mannheim, Germany
| | - Eric Poisel
- Cell Fate Engineering and Disease Modeling Group, German Cancer Research Center (DKFZ) and DKFZ-ZMBH Alliance, 69120, Heidelberg, Germany
- HITBR Hector Institute for Translational Brain Research gGmbH, 69120, Heidelberg, Germany
- Central Institute of Mental Health, Medical Faculty Mannheim, Heidelberg University, 68159, Mannheim, Germany
| | - Elisa Heinzelmann
- Cell Fate Engineering and Disease Modeling Group, German Cancer Research Center (DKFZ) and DKFZ-ZMBH Alliance, 69120, Heidelberg, Germany
- HITBR Hector Institute for Translational Brain Research gGmbH, 69120, Heidelberg, Germany
- Central Institute of Mental Health, Medical Faculty Mannheim, Heidelberg University, 68159, Mannheim, Germany
| | - Manu Saraswat
- Cell Fate Engineering and Disease Modeling Group, German Cancer Research Center (DKFZ) and DKFZ-ZMBH Alliance, 69120, Heidelberg, Germany
- HITBR Hector Institute for Translational Brain Research gGmbH, 69120, Heidelberg, Germany
- Central Institute of Mental Health, Medical Faculty Mannheim, Heidelberg University, 68159, Mannheim, Germany
- Faculty of Biosciences, Heidelberg University, 69120, Heidelberg, Germany
| | - Marleen Christ
- Cell Fate Engineering and Disease Modeling Group, German Cancer Research Center (DKFZ) and DKFZ-ZMBH Alliance, 69120, Heidelberg, Germany
- HITBR Hector Institute for Translational Brain Research gGmbH, 69120, Heidelberg, Germany
- Central Institute of Mental Health, Medical Faculty Mannheim, Heidelberg University, 68159, Mannheim, Germany
| | - Christian Arnold
- European Molecular Biology Laboratory, Structural and Computational Biology Unit, 69115, Heidelberg, Germany
| | - Ignacio L Ibarra
- European Molecular Biology Laboratory, Structural and Computational Biology Unit, 69115, Heidelberg, Germany
- Institute of Computational Biology, Helmholtz Zentrum München, German Research Center for Environmental Health, 85764, Neuherberg, Germany
| | - Joaquin Campos
- Chica and Heinz Schaller Research Group, Institute for Anatomy and Cell Biology, Heidelberg University, 69120, Heidelberg, Germany
| | - Jeroen Krijgsveld
- Division of Proteomics of Stem Cells and Cancer, German Cancer Research Center (DKFZ), 69120, Heidelberg, Germany
- Medical Faculty, Heidelberg University, 69120, Heidelberg, Germany
| | - Hannah Monyer
- Department of Clinical Neurobiology, University Hospital Heidelberg and DKFZ, Heidelberg, Germany
| | - Judith B Zaugg
- European Molecular Biology Laboratory, Structural and Computational Biology Unit, 69115, Heidelberg, Germany
| | - Claudio Acuna
- Chica and Heinz Schaller Research Group, Institute for Anatomy and Cell Biology, Heidelberg University, 69120, Heidelberg, Germany
| | - Moritz Mall
- Cell Fate Engineering and Disease Modeling Group, German Cancer Research Center (DKFZ) and DKFZ-ZMBH Alliance, 69120, Heidelberg, Germany.
- HITBR Hector Institute for Translational Brain Research gGmbH, 69120, Heidelberg, Germany.
- Central Institute of Mental Health, Medical Faculty Mannheim, Heidelberg University, 68159, Mannheim, Germany.
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5
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Trotter JH, Wang CY, Zhou P, Nakahara G, Südhof TC. A combinatorial code of neurexin-3 alternative splicing controls inhibitory synapses via a trans-synaptic dystroglycan signaling loop. Nat Commun 2023; 14:1771. [PMID: 36997523 PMCID: PMC10063607 DOI: 10.1038/s41467-023-36872-8] [Citation(s) in RCA: 16] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2022] [Accepted: 02/20/2023] [Indexed: 04/03/2023] Open
Abstract
Disrupted synaptic inhibition is implicated in neuropsychiatric disorders, yet the molecular mechanisms that shape and sustain inhibitory synapses are poorly understood. Here, we show through rescue experiments performed using Neurexin-3 conditional knockout mice that alternative splicing at SS2 and SS4 regulates the release probability, but not the number, of inhibitory synapses in the olfactory bulb and prefrontal cortex independent of sex. Neurexin-3 splice variants that mediate Neurexin-3 binding to dystroglycan enable inhibitory synapse function, whereas splice variants that don't allow dystroglycan binding do not. Furthermore, a minimal Neurexin-3 protein that binds to dystroglycan fully sustains inhibitory synaptic function, indicating that trans-synaptic dystroglycan binding is necessary and sufficient for Neurexin-3 function in inhibitory synaptic transmission. Thus, Neurexin-3 enables a normal release probability at inhibitory synapses via a trans-synaptic feedback signaling loop consisting of presynaptic Neurexin-3 and postsynaptic dystroglycan.
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Affiliation(s)
- Justin H Trotter
- Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, CA, 94305, USA.
| | - Cosmos Yuqi Wang
- Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, CA, 94305, USA
| | - Peng Zhou
- Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, CA, 94305, USA
| | - George Nakahara
- Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, CA, 94305, USA
| | - Thomas C Südhof
- Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, CA, 94305, USA.
- Howard Hughes Medical Institute, Stanford University School of Medicine, Stanford, CA, 94305, USA.
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6
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Chen Z, Liang Q, Wei Z, Chen X, Shi Q, Yu Z, Sun T. An Overview of In Vitro Biological Neural Networks for Robot Intelligence. CYBORG AND BIONIC SYSTEMS 2023; 4:0001. [PMID: 37040493 PMCID: PMC10076061 DOI: 10.34133/cbsystems.0001] [Citation(s) in RCA: 16] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2022] [Accepted: 10/17/2022] [Indexed: 01/12/2023] Open
Abstract
In vitro biological neural networks (BNNs) interconnected with robots, so-called BNN-based neurorobotic systems, can interact with the external world, so that they can present some preliminary intelligent behaviors, including learning, memory, robot control, etc. This work aims to provide a comprehensive overview of the intelligent behaviors presented by the BNN-based neurorobotic systems, with a particular focus on those related to robot intelligence. In this work, we first introduce the necessary biological background to understand the 2 characteristics of the BNNs: nonlinear computing capacity and network plasticity. Then, we describe the typical architecture of the BNN-based neurorobotic systems and outline the mainstream techniques to realize such an architecture from 2 aspects: from robots to BNNs and from BNNs to robots. Next, we separate the intelligent behaviors into 2 parts according to whether they rely solely on the computing capacity (computing capacity-dependent) or depend also on the network plasticity (network plasticity-dependent), which are then expounded respectively, with a focus on those related to the realization of robot intelligence. Finally, the development trends and challenges of the BNN-based neurorobotic systems are discussed.
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Affiliation(s)
- Zhe Chen
- School of Medical Technology, Beijing Institute of Technology, Beijing 100081, China
- Key Laboratory of Biomimetic Robots and Systems (Beijing Institute of Technology), Ministry of Education, Beijing 10081, China
- Advanced Innovation Center for Intelligent Robots and Systems, Beijing Institute of Technology, Beijing 100081, China
| | - Qian Liang
- Key Laboratory of Biomimetic Robots and Systems (Beijing Institute of Technology), Ministry of Education, Beijing 10081, China
- Advanced Innovation Center for Intelligent Robots and Systems, Beijing Institute of Technology, Beijing 100081, China
- School of Mechatronical Engineering, Beijing Institute of Technology, Beijing 100081, China
| | - Zihou Wei
- Key Laboratory of Biomimetic Robots and Systems (Beijing Institute of Technology), Ministry of Education, Beijing 10081, China
- Advanced Innovation Center for Intelligent Robots and Systems, Beijing Institute of Technology, Beijing 100081, China
- School of Mechatronical Engineering, Beijing Institute of Technology, Beijing 100081, China
| | - Xie Chen
- Key Laboratory of Biomimetic Robots and Systems (Beijing Institute of Technology), Ministry of Education, Beijing 10081, China
- Advanced Innovation Center for Intelligent Robots and Systems, Beijing Institute of Technology, Beijing 100081, China
- School of Mechatronical Engineering, Beijing Institute of Technology, Beijing 100081, China
| | - Qing Shi
- School of Medical Technology, Beijing Institute of Technology, Beijing 100081, China
- Key Laboratory of Biomimetic Robots and Systems (Beijing Institute of Technology), Ministry of Education, Beijing 10081, China
- Advanced Innovation Center for Intelligent Robots and Systems, Beijing Institute of Technology, Beijing 100081, China
- School of Mechatronical Engineering, Beijing Institute of Technology, Beijing 100081, China
| | - Zhiqiang Yu
- Key Laboratory of Biomimetic Robots and Systems (Beijing Institute of Technology), Ministry of Education, Beijing 10081, China
- Advanced Innovation Center for Intelligent Robots and Systems, Beijing Institute of Technology, Beijing 100081, China
- School of Mechatronical Engineering, Beijing Institute of Technology, Beijing 100081, China
| | - Tao Sun
- Key Laboratory of Biomimetic Robots and Systems (Beijing Institute of Technology), Ministry of Education, Beijing 10081, China
- Advanced Innovation Center for Intelligent Robots and Systems, Beijing Institute of Technology, Beijing 100081, China
- School of Mechatronical Engineering, Beijing Institute of Technology, Beijing 100081, China
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7
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McSweeney D, Gabriel R, Jin K, Pang ZP, Aronow B, Pak C. CASK loss of function differentially regulates neuronal maturation and synaptic function in human induced cortical excitatory neurons. iScience 2022; 25:105187. [PMID: 36262316 PMCID: PMC9574418 DOI: 10.1016/j.isci.2022.105187] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2022] [Revised: 08/30/2022] [Accepted: 09/20/2022] [Indexed: 12/14/2022] Open
Abstract
Loss-of-function (LOF) mutations in CASK cause severe developmental phenotypes, including microcephaly with pontine and cerebellar hypoplasia, X-linked intellectual disability, and autism. Unraveling the pathological mechanisms of CASK-related disorders has been challenging owing to limited human cellular models to study the dynamic roles of this molecule during neuronal maturation and synapse development. Here, we investigate cell-autonomous functions of CASK in cortical excitatory induced neurons (iNs) generated from CASK knockout (KO) isogenic human embryonic stem cells (hESCs) using gene expression, morphometrics, and electrophysiology. While immature CASK KO iNs show robust neuronal outgrowth, mature CASK KO iNs display severe defects in synaptic transmission and synchronized network activity without compromising neuronal morphology and synapse numbers. In the developing human cortical excitatory neurons, CASK functions to promote both structural integrity and establishment of cortical excitatory neuronal networks. These results lay the foundation for future studies identifying suppressors of such phenotypes relevant to human patients.
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Affiliation(s)
- Danny McSweeney
- Graduate Program in Molecular and Cellular Biology, UMass Amherst, Amherst, MA 01003, USA,Department of Biochemistry and Molecular Biology, UMass Amherst, Amherst, MA 01003, USA
| | - Rafael Gabriel
- Department of Biochemistry and Molecular Biology, UMass Amherst, Amherst, MA 01003, USA
| | - Kang Jin
- Departments of Biomedical Informatics, Pediatrics, University of Cincinnati, Cincinnati Children’s Hospital Medical Center, Cincinnati, OH 45229, USA
| | - Zhiping P. Pang
- Child Health Institute of New Jersey and Department of Neuroscience and Cell Biology, Robert Wood Johnson Medical School, Rutgers University, New Brunswick, NJ 08901, USA
| | - Bruce Aronow
- Departments of Biomedical Informatics, Pediatrics, University of Cincinnati, Cincinnati Children’s Hospital Medical Center, Cincinnati, OH 45229, USA
| | - ChangHui Pak
- Department of Biochemistry and Molecular Biology, UMass Amherst, Amherst, MA 01003, USA,Corresponding author
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8
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Sahyoun C, Krezel W, Mattei C, Sabatier JM, Legros C, Fajloun Z, Rima M. Neuro- and Cardiovascular Activities of Montivipera bornmuelleri Snake Venom. BIOLOGY 2022; 11:biology11060888. [PMID: 35741410 PMCID: PMC9219918 DOI: 10.3390/biology11060888] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/11/2022] [Revised: 06/04/2022] [Accepted: 06/06/2022] [Indexed: 12/31/2022]
Abstract
Simple Summary Snake venoms are rich in molecules acting on different biological systems, and they are responsible for the complications following snake bite envenoming. These bioactive molecules are of interest in pharmaceutical industries as templates for drug design. Different biological activities of Montivipera bornmuelleri snake venom have been already studied; however, the venom’s activity on the nervous system has not yet been studied, and its effect on the cardiovascular system needs further investigation. Herein, we show that this venom induces toxicity on the nervous system and disrupts the cardiovascular system, highlighting a broad spectrum of biological activities. Abstract The complications following snake bite envenoming are due to the venom’s biological activities, which can act on different systems of the prey. These activities arise from the fact that snake venoms are rich in bioactive molecules, which are also of interest for designing drugs. The venom of Montivipera bornmuelleri, known as the Lebanon viper, has been shown to exert antibacterial, anticancer, and immunomodulatory effects. However, the venom’s activity on the nervous system has not yet been studied, and its effect on the cardiovascular system needs further investigation. Because zebrafish is a convenient model to study tissue alterations induced by toxic agents, we challenged it with the venom of Montivipera bornmuelleri. We show that this venom leads to developmental toxicity but not teratogenicity in zebrafish embryos. The venom also induces neurotoxic effects and disrupts the zebrafish cardiovascular system, leading to heartbeat rate reduction and hemorrhage. Our findings demonstrate the potential neurotoxicity and cardiotoxicity of M. bornmuelleri’s venom, suggesting a multitarget strategy during envenomation.
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Affiliation(s)
- Christina Sahyoun
- INSERM, CNRS, MITOVASC, Equipe CarMe, SFR ICAT, University of Angers, 49000 Angers, France; (C.S.); (C.M.); (C.L.)
- Laboratory of Applied Biotechnology (LBA3B), Azm Center for Research in Biotechnology and Its Applications, EDST, Lebanese University, Tripoli 1300, Lebanon
| | - Wojciech Krezel
- Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), INSERM, CNRS, Université de Strasbourg, 67400 Illkirch, France;
| | - César Mattei
- INSERM, CNRS, MITOVASC, Equipe CarMe, SFR ICAT, University of Angers, 49000 Angers, France; (C.S.); (C.M.); (C.L.)
| | - Jean-Marc Sabatier
- CNRS, INP, Institute of Neurophysiopathology, Aix-Marseille University, 13385 Marseille, France
- Correspondence: (J.-M.S.); (Z.F.); (M.R.)
| | - Christian Legros
- INSERM, CNRS, MITOVASC, Equipe CarMe, SFR ICAT, University of Angers, 49000 Angers, France; (C.S.); (C.M.); (C.L.)
| | - Ziad Fajloun
- Laboratory of Applied Biotechnology (LBA3B), Azm Center for Research in Biotechnology and Its Applications, EDST, Lebanese University, Tripoli 1300, Lebanon
- Department of Biology, Faculty of Sciences 3, Campus Michel Slayman, Lebanese University, Tripoli 1352, Lebanon
- Correspondence: (J.-M.S.); (Z.F.); (M.R.)
| | - Mohamad Rima
- Laboratory of Applied Biotechnology (LBA3B), Azm Center for Research in Biotechnology and Its Applications, EDST, Lebanese University, Tripoli 1300, Lebanon
- Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), INSERM, CNRS, Université de Strasbourg, 67400 Illkirch, France;
- Correspondence: (J.-M.S.); (Z.F.); (M.R.)
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9
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Wang J, Miao Y, Wicklein R, Sun Z, Wang J, Jude KM, Fernandes RA, Merrill SA, Wernig M, Garcia KC, Südhof TC. RTN4/NoGo-receptor binding to BAI adhesion-GPCRs regulates neuronal development. Cell 2021; 184:5869-5885.e25. [PMID: 34758294 PMCID: PMC8620742 DOI: 10.1016/j.cell.2021.10.016] [Citation(s) in RCA: 36] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2021] [Revised: 06/01/2021] [Accepted: 10/13/2021] [Indexed: 10/19/2022]
Abstract
RTN4-binding proteins were widely studied as "NoGo" receptors, but their physiological interactors and roles remain elusive. Similarly, BAI adhesion-GPCRs were associated with numerous activities, but their ligands and functions remain unclear. Using unbiased approaches, we observed an unexpected convergence: RTN4 receptors are high-affinity ligands for BAI adhesion-GPCRs. A single thrombospondin type 1-repeat (TSR) domain of BAIs binds to the leucine-rich repeat domain of all three RTN4-receptor isoforms with nanomolar affinity. In the 1.65 Å crystal structure of the BAI1/RTN4-receptor complex, C-mannosylation of tryptophan and O-fucosylation of threonine in the BAI TSR-domains creates a RTN4-receptor/BAI interface shaped by unusual glycoconjugates that enables high-affinity interactions. In human neurons, RTN4 receptors regulate dendritic arborization, axonal elongation, and synapse formation by differential binding to glial versus neuronal BAIs, thereby controlling neural network activity. Thus, BAI binding to RTN4/NoGo receptors represents a receptor-ligand axis that, enabled by rare post-translational modifications, controls development of synaptic circuits.
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Affiliation(s)
- Jie Wang
- Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Yi Miao
- Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, CA 94305, USA; Howard Hughes Medical Institute, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Rebecca Wicklein
- Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Zijun Sun
- Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Jinzhao Wang
- Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, CA 94305, USA; Institute for Stem Cell Biology and Regenerative Medicine, Department of Pathology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Kevin M Jude
- Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, CA 94305, USA; Howard Hughes Medical Institute, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Ricardo A Fernandes
- Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, CA 94305, USA; Howard Hughes Medical Institute, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Sean A Merrill
- Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Marius Wernig
- Institute for Stem Cell Biology and Regenerative Medicine, Department of Pathology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - K Christopher Garcia
- Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, CA 94305, USA; Howard Hughes Medical Institute, Stanford University School of Medicine, Stanford, CA 94305, USA; Department of Structural Biology, Stanford University School of Medicine, Stanford, CA 94305, USA.
| | - Thomas C Südhof
- Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, CA 94305, USA; Howard Hughes Medical Institute, Stanford University School of Medicine, Stanford, CA 94305, USA.
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10
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Mirabella F, Desiato G, Mancinelli S, Fossati G, Rasile M, Morini R, Markicevic M, Grimm C, Amegandjin C, Termanini A, Peano C, Kunderfranco P, di Cristo G, Zerbi V, Menna E, Lodato S, Matteoli M, Pozzi D. Prenatal interleukin 6 elevation increases glutamatergic synapse density and disrupts hippocampal connectivity in offspring. Immunity 2021; 54:2611-2631.e8. [PMID: 34758338 PMCID: PMC8585508 DOI: 10.1016/j.immuni.2021.10.006] [Citation(s) in RCA: 58] [Impact Index Per Article: 19.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2020] [Revised: 04/24/2021] [Accepted: 10/07/2021] [Indexed: 02/07/2023]
Abstract
Early prenatal inflammatory conditions are thought to be a risk factor for different neurodevelopmental disorders. Maternal interleukin-6 (IL-6) elevation during pregnancy causes abnormal behavior in offspring, but whether these defects result from altered synaptic developmental trajectories remains unclear. Here we showed that transient IL-6 elevation via injection into pregnant mice or developing embryos enhanced glutamatergic synapses and led to overall brain hyperconnectivity in offspring into adulthood. IL-6 activated synaptogenesis gene programs in glutamatergic neurons and required the transcription factor STAT3 and expression of the RGS4 gene. The STAT3-RGS4 pathway was also activated in neonatal brains during poly(I:C)-induced maternal immune activation, which mimics viral infection during pregnancy. These findings indicate that IL-6 elevation at early developmental stages is sufficient to exert a long-lasting effect on glutamatergic synaptogenesis and brain connectivity, providing a mechanistic framework for the association between prenatal inflammatory events and brain neurodevelopmental disorders.
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Affiliation(s)
- Filippo Mirabella
- Department of Biomedical Sciences, Humanitas University, Via Rita Levi Montalcini 4, 20090 Pieve Emanuele, Milan, Italy; IRCCS Humanitas Research Hospital, via Manzoni 56, 20089 Rozzano, Milan, Italy
| | - Genni Desiato
- IRCCS Humanitas Research Hospital, via Manzoni 56, 20089 Rozzano, Milan, Italy; Institute of Neuroscience - National Research Council, 20139 Milan, Italy
| | - Sara Mancinelli
- IRCCS Humanitas Research Hospital, via Manzoni 56, 20089 Rozzano, Milan, Italy
| | - Giuliana Fossati
- IRCCS Humanitas Research Hospital, via Manzoni 56, 20089 Rozzano, Milan, Italy
| | - Marco Rasile
- Department of Biomedical Sciences, Humanitas University, Via Rita Levi Montalcini 4, 20090 Pieve Emanuele, Milan, Italy
| | - Raffaella Morini
- IRCCS Humanitas Research Hospital, via Manzoni 56, 20089 Rozzano, Milan, Italy
| | - Marija Markicevic
- Neuroscience Center Zürich, ETH Zürich and University of Zürich, Zürich 8057, Switzerland
| | - Christina Grimm
- Neuroscience Center Zürich, ETH Zürich and University of Zürich, Zürich 8057, Switzerland
| | - Clara Amegandjin
- Department of Neurosciences, Université de Montréal, Montréal, QC, Canada; CHU Sainte-Justine Research Center, Montréal, QC, Canada
| | - Alberto Termanini
- Bioinformatic Unit, Humanitas Clinical and Research Center, 20089 Rozzano, Milan, Italy
| | - Clelia Peano
- Institute of Genetic and Biomedical Research, UoS Milan, National Research Council, 20089 Rozzano, Milan, Italy; Genomic Unit, Humanitas Clinical and Research Center, 20089 Rozzano, Milan, Italy
| | - Paolo Kunderfranco
- Bioinformatic Unit, Humanitas Clinical and Research Center, 20089 Rozzano, Milan, Italy
| | - Graziella di Cristo
- Department of Neurosciences, Université de Montréal, Montréal, QC, Canada; CHU Sainte-Justine Research Center, Montréal, QC, Canada
| | - Valerio Zerbi
- Neuroscience Center Zürich, ETH Zürich and University of Zürich, Zürich 8057, Switzerland; Neural Control of Movement Lab, Department of Health Sciences and Technology, ETH Zürich, Zürich 8057, Switzerland
| | - Elisabetta Menna
- IRCCS Humanitas Research Hospital, via Manzoni 56, 20089 Rozzano, Milan, Italy; Institute of Neuroscience - National Research Council, 20139 Milan, Italy
| | - Simona Lodato
- Department of Biomedical Sciences, Humanitas University, Via Rita Levi Montalcini 4, 20090 Pieve Emanuele, Milan, Italy; IRCCS Humanitas Research Hospital, via Manzoni 56, 20089 Rozzano, Milan, Italy
| | - Michela Matteoli
- IRCCS Humanitas Research Hospital, via Manzoni 56, 20089 Rozzano, Milan, Italy; Institute of Neuroscience - National Research Council, 20139 Milan, Italy.
| | - Davide Pozzi
- Department of Biomedical Sciences, Humanitas University, Via Rita Levi Montalcini 4, 20090 Pieve Emanuele, Milan, Italy; IRCCS Humanitas Research Hospital, via Manzoni 56, 20089 Rozzano, Milan, Italy.
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11
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O'Neil SD, Rácz B, Brown WE, Gao Y, Soderblom EJ, Yasuda R, Soderling SH. Action potential-coupled Rho GTPase signaling drives presynaptic plasticity. eLife 2021; 10:63756. [PMID: 34269176 PMCID: PMC8285108 DOI: 10.7554/elife.63756] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2020] [Accepted: 07/06/2021] [Indexed: 12/30/2022] Open
Abstract
In contrast to their postsynaptic counterparts, the contributions of activity-dependent cytoskeletal signaling to presynaptic plasticity remain controversial and poorly understood. To identify and evaluate these signaling pathways, we conducted a proteomic analysis of the presynaptic cytomatrix using in vivo biotin identification (iBioID). The resultant proteome was heavily enriched for actin cytoskeleton regulators, including Rac1, a Rho GTPase that activates the Arp2/3 complex to nucleate branched actin filaments. Strikingly, we find Rac1 and Arp2/3 are closely associated with synaptic vesicle membranes in adult mice. Using three independent approaches to alter presynaptic Rac1 activity (genetic knockout, spatially restricted inhibition, and temporal optogenetic manipulation), we discover that this pathway negatively regulates synaptic vesicle replenishment at both excitatory and inhibitory synapses, bidirectionally sculpting short-term synaptic depression. Finally, we use two-photon fluorescence lifetime imaging to show that presynaptic Rac1 activation is coupled to action potentials by voltage-gated calcium influx. Thus, this study uncovers a previously unrecognized mechanism of actin-regulated short-term presynaptic plasticity that is conserved across excitatory and inhibitory terminals. It also provides a new proteomic framework for better understanding presynaptic physiology, along with a blueprint of experimental strategies to isolate the presynaptic effects of ubiquitously expressed proteins.
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Affiliation(s)
| | - Bence Rácz
- Department of Anatomy and Histology, University of Veterinary Medicine, Budapest, Hungary
| | - Walter Evan Brown
- Department of Cell Biology, Duke University Medical Center, Durham, United States
| | - Yudong Gao
- Department of Cell Biology, Duke University Medical Center, Durham, United States
| | - Erik J Soderblom
- Department of Cell Biology, Duke University Medical Center, Durham, United States.,Proteomics and Metabolomics Shared Resource and Center for Genomic and Computational Biology, Duke University Medical Center, Durham, United States
| | - Ryohei Yasuda
- Max Planck Florida Institute for Neuroscience, Jupiter, United States
| | - Scott H Soderling
- Department of Neurobiology, Duke University Medical Center, Durham, United States.,Department of Cell Biology, Duke University Medical Center, Durham, United States
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12
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Ng YH, Chanda S, Janas JA, Yang N, Kokubu Y, Südhof TC, Wernig M. Efficient generation of dopaminergic induced neuronal cells with midbrain characteristics. Stem Cell Reports 2021; 16:1763-1776. [PMID: 34171286 PMCID: PMC8282497 DOI: 10.1016/j.stemcr.2021.05.017] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2015] [Revised: 05/22/2021] [Accepted: 05/23/2021] [Indexed: 12/12/2022] Open
Abstract
The differentiation of pluripotent stem cells can be accomplished by sequential activation of signaling pathways or through transcription factor programming. Multistep differentiation imitates embryonic development to obtain authentic cell types, but it suffers from asynchronous differentiation with variable efficiency. Transcription factor programming induces synchronous and efficient differentiation with higher reproducibility but may not always yield authentic cell types. We systematically explored the generation of dopaminergic induced neuronal cells from mouse and human pluripotent stem cells. We found that the proneural factor Ascl1 in combination with mesencephalic factors Lmx1a and Nurr1 induce peripheral dopaminergic neurons. Co-delivery of additional midbrain transcription factors En1, FoxA2, and Pitx3 resulted in facile and robust generation of functional dopaminergic neurons of midbrain character. Our results suggest that more complex combinations of transcription factors may be needed for proper regional specification of induced neuronal cells generated by direct lineage induction. Ascl1 alone can induce tyrosine hydroxylase (TH)-positive ES-iN cells Ascl1 alone, or with Nurr1 and Lmx1a, induce peripheral TH-positive cells WNT1 and neurotrophic factors increase TH-positive iN cells in culture A 6-factor combination induces TH-positive dopamine iN cells of central identity
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Affiliation(s)
- Yi Han Ng
- Institute for Stem Cell Biology and Regenerative Medicine and Department of Pathology, Stanford University School of Medicine, Stanford, CA 94305, USA; Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, CA 94305, USA; Department of Molecular and Cellular Physiology and Howard Hughes Medical Institute, Stanford, CA 94305, USA
| | - Soham Chanda
- Institute for Stem Cell Biology and Regenerative Medicine and Department of Pathology, Stanford University School of Medicine, Stanford, CA 94305, USA; Department of Molecular and Cellular Physiology and Howard Hughes Medical Institute, Stanford, CA 94305, USA
| | - Justyna A Janas
- Institute for Stem Cell Biology and Regenerative Medicine and Department of Pathology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Nan Yang
- Institute for Stem Cell Biology and Regenerative Medicine and Department of Pathology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Yuko Kokubu
- Institute for Stem Cell Biology and Regenerative Medicine and Department of Pathology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Thomas C Südhof
- Department of Molecular and Cellular Physiology and Howard Hughes Medical Institute, Stanford, CA 94305, USA
| | - Marius Wernig
- Institute for Stem Cell Biology and Regenerative Medicine and Department of Pathology, Stanford University School of Medicine, Stanford, CA 94305, USA.
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13
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Cross-platform validation of neurotransmitter release impairments in schizophrenia patient-derived NRXN1-mutant neurons. Proc Natl Acad Sci U S A 2021; 118:2025598118. [PMID: 34035170 DOI: 10.1073/pnas.2025598118] [Citation(s) in RCA: 43] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Heterozygous NRXN1 deletions constitute the most prevalent currently known single-gene mutation associated with schizophrenia, and additionally predispose to multiple other neurodevelopmental disorders. Engineered heterozygous NRXN1 deletions impaired neurotransmitter release in human neurons, suggesting a synaptic pathophysiological mechanism. Utilizing this observation for drug discovery, however, requires confidence in its robustness and validity. Here, we describe a multicenter effort to test the generality of this pivotal observation, using independent analyses at two laboratories of patient-derived and newly engineered human neurons with heterozygous NRXN1 deletions. Using neurons transdifferentiated from induced pluripotent stem cells that were derived from schizophrenia patients carrying heterozygous NRXN1 deletions, we observed the same synaptic impairment as in engineered NRXN1-deficient neurons. This impairment manifested as a large decrease in spontaneous synaptic events, in evoked synaptic responses, and in synaptic paired-pulse depression. Nrxn1-deficient mouse neurons generated from embryonic stem cells by the same method as human neurons did not exhibit impaired neurotransmitter release, suggesting a human-specific phenotype. Human NRXN1 deletions produced a reproducible increase in the levels of CASK, an intracellular NRXN1-binding protein, and were associated with characteristic gene-expression changes. Thus, heterozygous NRXN1 deletions robustly impair synaptic function in human neurons regardless of genetic background, enabling future drug discovery efforts.
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14
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Alten B, Zhou Q, Shin OH, Esquivies L, Lin PY, White KI, Sun R, Chung WK, Monteggia LM, Brunger AT, Kavalali ET. Role of Aberrant Spontaneous Neurotransmission in SNAP25-Associated Encephalopathies. Neuron 2020; 109:59-72.e5. [PMID: 33147442 DOI: 10.1016/j.neuron.2020.10.012] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2020] [Revised: 09/09/2020] [Accepted: 10/07/2020] [Indexed: 01/19/2023]
Abstract
SNARE (soluble N-ethylmaleimide sensitive factor attachment protein receptor) complex, composed of synaptobrevin, syntaxin, and SNAP25, forms the essential fusion machinery for neurotransmitter release. Recent studies have reported several mutations in the gene encoding SNAP25 as a causative factor for developmental and epileptic encephalopathies of infancy and childhood with diverse clinical manifestations. However, it remains unclear how SNAP25 mutations give rise to these disorders. Here, we show that although structurally clustered mutations in SNAP25 give rise to related synaptic transmission phenotypes, specific alterations in spontaneous neurotransmitter release are a key factor to account for disease heterogeneity. Importantly, we identified a single mutation that augments spontaneous release without altering evoked release, suggesting that aberrant spontaneous release is sufficient to cause disease in humans.
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Affiliation(s)
- Baris Alten
- Department of Pharmacology, Vanderbilt University, Nashville, TN 37240-7933, USA; Vanderbilt Brain Institute, Vanderbilt University, Nashville, TN 37240-7933, USA
| | - Qiangjun Zhou
- Department of Pharmacology, Vanderbilt University, Nashville, TN 37240-7933, USA; Vanderbilt Brain Institute, Vanderbilt University, Nashville, TN 37240-7933, USA; Department of Cell and Developmental Biology, Vanderbilt University, Nashville, TN 37240-7933, USA
| | - Ok-Ho Shin
- Department of Pharmacology, Vanderbilt University, Nashville, TN 37240-7933, USA; Vanderbilt Brain Institute, Vanderbilt University, Nashville, TN 37240-7933, USA
| | - Luis Esquivies
- Department of Molecular and Cellular Physiology, Howard Hughes Medical Institute, Stanford University, Stanford, CA 94305, USA
| | - Pei-Yi Lin
- Department of Pharmacology, Vanderbilt University, Nashville, TN 37240-7933, USA; Vanderbilt Brain Institute, Vanderbilt University, Nashville, TN 37240-7933, USA
| | - K Ian White
- Department of Molecular and Cellular Physiology, Howard Hughes Medical Institute, Stanford University, Stanford, CA 94305, USA
| | - Rong Sun
- Department of Pharmacology, Vanderbilt University, Nashville, TN 37240-7933, USA; Vanderbilt Brain Institute, Vanderbilt University, Nashville, TN 37240-7933, USA; Department of Cell and Developmental Biology, Vanderbilt University, Nashville, TN 37240-7933, USA
| | - Wendy K Chung
- Department of Pediatrics (in Medicine), Columbia University Medical Center, New York, NY 10032, USA
| | - Lisa M Monteggia
- Department of Pharmacology, Vanderbilt University, Nashville, TN 37240-7933, USA; Vanderbilt Brain Institute, Vanderbilt University, Nashville, TN 37240-7933, USA
| | - Axel T Brunger
- Department of Molecular and Cellular Physiology, Howard Hughes Medical Institute, Stanford University, Stanford, CA 94305, USA
| | - Ege T Kavalali
- Department of Pharmacology, Vanderbilt University, Nashville, TN 37240-7933, USA; Vanderbilt Brain Institute, Vanderbilt University, Nashville, TN 37240-7933, USA.
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15
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Chen Y, Kunath T, Simpson J, Homer N, Sylantyev S. Synaptic signalling in a network of dopamine neurons: what prevents proper intercellular crosstalk? FEBS Lett 2020; 594:3272-3292. [PMID: 33073864 DOI: 10.1002/1873-3468.13910] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2020] [Revised: 08/06/2020] [Accepted: 08/07/2020] [Indexed: 01/09/2023]
Abstract
Human embryonic stem cell (hESC)-derived midbrain dopamine (DA) neurons stand out as a cell source for transplantation with their sustainability and consistency superior to the formerly used fetal tissues. However, multiple studies of DA neurons in culture failed to register action potential (AP) generation upon synaptic input. To test whether this is due to deficiency of NMDA receptor (NMDAR) coagonists released from astroglia, we studied the functional properties of neural receptors in hESC-derived DA neuronal cultures. We find that, apart from an insufficient amount of coagonists, lack of interneuronal crosstalk is caused by hypofunction of synaptic NMDARs due to their direct inhibition by synaptically released DA. This inhibitory tone is independent of DA receptors and affects the NMDAR coagonist binding site.
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Affiliation(s)
- Yixi Chen
- MRC Centre for Regenerative Medicine, Institute for Stem Cell Research, University of Edinburgh, Edinburgh, UK.,UK Centre for Mammalian Synthetic Biology, University of Edinburgh, Edinburgh, UK
| | - Tilo Kunath
- MRC Centre for Regenerative Medicine, Institute for Stem Cell Research, University of Edinburgh, Edinburgh, UK.,UK Centre for Mammalian Synthetic Biology, University of Edinburgh, Edinburgh, UK
| | - Joanna Simpson
- Mass Spectrometry Core, Edinburgh Clinical Research Facility, Queen's Medical Research Institute, University of Edinburgh, Edinburgh, UK
| | - Natalie Homer
- Mass Spectrometry Core, Edinburgh Clinical Research Facility, Queen's Medical Research Institute, University of Edinburgh, Edinburgh, UK
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16
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SPARCL1 Promotes Excitatory But Not Inhibitory Synapse Formation and Function Independent of Neurexins and Neuroligins. J Neurosci 2020; 40:8088-8102. [PMID: 32973045 DOI: 10.1523/jneurosci.0454-20.2020] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2020] [Revised: 06/17/2020] [Accepted: 07/12/2020] [Indexed: 12/17/2022] Open
Abstract
Emerging evidence supports roles for secreted extracellular matrix proteins in boosting synaptogenesis, synaptic transmission, and synaptic plasticity. SPARCL1 (also known as Hevin), a secreted non-neuronal protein, was reported to increase synaptogenesis by simultaneously binding to presynaptic neurexin-1α and to postsynaptic neuroligin-1B, thereby catalyzing formation of trans-synaptic neurexin/neuroligin complexes. However, neurexins and neuroligins do not themselves mediate synaptogenesis, raising the question of how SPARCL1 enhances synapse formation by binding to these molecules. Moreover, it remained unclear whether SPARCL1 acts on all synapses containing neurexins and neuroligins or only on a subset of synapses, and whether it enhances synaptic transmission in addition to boosting synaptogenesis or induces silent synapses. To explore these questions, we examined the synaptic effects of SPARCL1 and their dependence on neurexins and neuroligins. Using mixed neuronal and glial cultures from neonatal mouse cortex of both sexes, we show that SPARCL1 selectively increases excitatory but not inhibitory synapse numbers, enhances excitatory but not inhibitory synaptic transmission, and augments NMDAR-mediated synaptic responses more than AMPAR-mediated synaptic responses. None of these effects were mediated by SPARCL1-binding to neurexins or neuroligins. Neurons from triple neurexin-1/2/3 or from quadruple neuroligin-1/2/3/4 conditional KO mice that lacked all neurexins or all neuroligins were fully responsive to SPARCL1. Together, our results reveal that SPARCL1 selectively boosts excitatory but not inhibitory synaptogenesis and synaptic transmission by a novel mechanism that is independent of neurexins and neuroligins.SIGNIFICANCE STATEMENT Emerging evidence supports roles for extracellular matrix proteins in boosting synapse formation and function. Previous studies demonstrated that SPARCL1, a secreted non-neuronal protein, promotes synapse formation in rodent and human neurons. However, it remained unclear whether SPARCL1 acts on all or on only a subset of synapses, induces functional or largely inactive synapses, and generates synapses by bridging presynaptic neurexins and postsynaptic neuroligins. Here, we report that SPARCL1 selectively induces excitatory synapses, increases their efficacy, and enhances their NMDAR content. Moreover, using rigorous genetic manipulations, we show that SPARCL1 does not require neurexins and neuroligins for its activity. Thus, SPARCL1 selectively boosts excitatory synaptogenesis and synaptic transmission by a novel mechanism that is independent of neurexins and neuroligins.
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17
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Scarnati MS, Boreland AJ, Joel M, Hart RP, Pang ZP. Differential sensitivity of human neurons carrying μ opioid receptor (MOR) N40D variants in response to ethanol. Alcohol 2020; 87:97-109. [PMID: 32561311 PMCID: PMC7958146 DOI: 10.1016/j.alcohol.2020.05.004] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2020] [Revised: 05/15/2020] [Accepted: 05/25/2020] [Indexed: 12/11/2022]
Abstract
The acute and chronic effects of alcohol on the brain and behavior are linked to alterations in inhibitory synaptic transmission. Alcohol's most consistent effect at the synaptic level is probably a facilitation of γ-aminobutyric acid (GABA) release, as seen from several rodent studies. The impact of alcohol on GABAergic neurotransmission in human neurons is unknown, due to a lack of a suitable experimental model. Human neurons can also be used to model effects of genetic variants linked with alcohol use disorders (AUDs). The A118G single nucleotide polymorphism (SNP rs1799971) of the OPRM1 gene encoding the N40D (D40 minor allele) mu-opioid receptor (MOR) variant has been linked with individuals who have an AUD. However, while N40D is clearly associated with other drugs of abuse, involvement with AUDs is controversial. In this study, we employed Ascl1-and Dlx2-induced inhibitory neuronal cells (AD-iNs) generated from human iPS cell lines carrying N40D variants, and investigated the impact of ethanol acutely and chronically on GABAergic synaptic transmission. We found that N40 AD-iNs display a stronger facilitation (versus D40) of spontaneous and miniature inhibitory postsynaptic current frequency in response to acute ethanol application. Quantitative immunocytochemistry of Synapsin 1+ synaptic puncta revealed a similar synapse number between N40 and D40 iNs, suggesting an ethanol modulation of presynaptic GABA release without affecting synapse density. Interestingly, D40 iNs exposed to chronic intermittent ethanol application caused a significant increase in mIPSC frequency, with only a modest enhancement observed in N40 iNs. These data suggest that the MOR genotype may confer differential sensitivity to synaptic output, which depends on ethanol exposure time and concentration for AD-iNs and may help explain alcohol dependence in individuals who carry the MOR D40 SNPs. Furthermore, this study supports the use of human neuronal cells carrying risk-associated genetic variants linked to disease, as in vitro models to assay the synaptic actions of alcohol on human neuronal cells.
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Affiliation(s)
- Matthew S Scarnati
- Child Health Institute of New Jersey, Rutgers Robert Wood Johnson Medical School, Rutgers University, New Brunswick, NJ, 08901, USA; Department of Neuroscience and Cell Biology, Rutgers Robert Wood Johnson Medical School, Rutgers University, New Brunswick, NJ, 08901, USA
| | - Andrew J Boreland
- Child Health Institute of New Jersey, Rutgers Robert Wood Johnson Medical School, Rutgers University, New Brunswick, NJ, 08901, USA; Department of Neuroscience and Cell Biology, Rutgers Robert Wood Johnson Medical School, Rutgers University, New Brunswick, NJ, 08901, USA
| | - Marisa Joel
- Child Health Institute of New Jersey, Rutgers Robert Wood Johnson Medical School, Rutgers University, New Brunswick, NJ, 08901, USA; Department of Cell Biology and Neuroscience, Rutgers University, Piscataway, NJ, 08854, USA
| | - Ronald P Hart
- Department of Cell Biology and Neuroscience, Rutgers University, Piscataway, NJ, 08854, USA; Human Genetics Institute of New Jersey, Piscataway, NJ, 08854, USA
| | - Zhiping P Pang
- Child Health Institute of New Jersey, Rutgers Robert Wood Johnson Medical School, Rutgers University, New Brunswick, NJ, 08901, USA; Department of Neuroscience and Cell Biology, Rutgers Robert Wood Johnson Medical School, Rutgers University, New Brunswick, NJ, 08901, USA.
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18
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Addiction associated N40D mu-opioid receptor variant modulates synaptic function in human neurons. Mol Psychiatry 2020; 25:1406-1419. [PMID: 31481756 PMCID: PMC7051890 DOI: 10.1038/s41380-019-0507-0] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/17/2019] [Revised: 06/07/2019] [Accepted: 07/09/2019] [Indexed: 02/06/2023]
Abstract
The OPRM1 A118G single nucleotide polymorphism (SNP rs1799971) gene variant encoding the N40D µ-opioid receptor (MOR) has been associated with dependence on opiates and other drugs of abuse but its mechanism is unknown. The frequency of G-allele carriers is ~40% in Asians, ~16% in Europeans, and ~3% in African-Americans. With opioid abuse-related deaths rising at unprecedented rates, understanding these mechanisms may provide a path to therapy. Here we generated homozygous N40D subject-specific induced inhibitory neuronal cells (iNs) from seven human-induced pluripotent stem (iPS) cell lines from subjects of European descent (both male and female) and probed the impact of N40D MOR regulation on synaptic transmission. We found that D40 iNs exhibit consistently stronger suppression (versus N40) of spontaneous inhibitory postsynaptic currents (sIPSCs) across multiple subjects. To mitigate the confounding effects of background genetic variation on neuronal function, the regulatory effects of MORs on synaptic transmission were recapitulated in two sets of independently engineered isogenic N40D iNs. In addition, we employed biochemical analysis and observed differential N-linked glycosylation of human MOR N40D. This study identifies neurophysiological and molecular differences between human MOR variants that may predict altered opioid responsivity and/or dependence in this subset of individuals.
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19
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Naseri NN, Ergel B, Kharel P, Na Y, Huang Q, Huang R, Dolzhanskaya N, Burré J, Velinov MT, Sharma M. Aggregation of mutant cysteine string protein-α via Fe-S cluster binding is mitigated by iron chelators. Nat Struct Mol Biol 2020; 27:192-201. [PMID: 32042150 PMCID: PMC7021000 DOI: 10.1038/s41594-020-0375-y] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2019] [Accepted: 01/08/2020] [Indexed: 01/27/2023]
Abstract
Point mutations in cysteine string protein-α (CSPα) cause dominantly inherited adult-onset neuronal ceroid lipofuscinosis (ANCL), a rapidly progressing and lethal neurodegenerative disease with no treatment. ANCL mutations are proposed to trigger CSPα aggregation/oligomerization, but the mechanism of oligomer formation remains unclear. Here we use purified proteins, mouse primary neurons and patient-derived induced neurons to show that the normally palmitoylated cysteine string region of CSPα loses palmitoylation in ANCL mutants. This allows oligomerization of mutant CSPα via ectopic binding of iron-sulfur (Fe-S) clusters. The resulting oligomerization of mutant CSPα causes its mislocalization and consequent loss of its synaptic SNARE-chaperoning function. We then find that pharmacological iron chelation mitigates the oligomerization of mutant CSPα, accompanied by partial rescue of the downstream SNARE defects and the pathological hallmark of lipofuscin accumulation. Thus, the iron chelators deferiprone (L1) and deferoxamine (Dfx), which are already used to treat iron overload in humans, offer a new approach for treating ANCL.
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Affiliation(s)
- Nima N Naseri
- Appel Institute for Alzheimer's Disease Research, and Brain & Mind Research Institute, Weill Cornell Medicine, New York, NY, USA
| | - Burçe Ergel
- Appel Institute for Alzheimer's Disease Research, and Brain & Mind Research Institute, Weill Cornell Medicine, New York, NY, USA
| | - Parinati Kharel
- Appel Institute for Alzheimer's Disease Research, and Brain & Mind Research Institute, Weill Cornell Medicine, New York, NY, USA
| | - Yoonmi Na
- Appel Institute for Alzheimer's Disease Research, and Brain & Mind Research Institute, Weill Cornell Medicine, New York, NY, USA
| | - Qingqiu Huang
- Cornell High Energy Synchrotron Source (CHESS), Cornell University, Ithaca, NY, USA
| | - Rong Huang
- Cornell High Energy Synchrotron Source (CHESS), Cornell University, Ithaca, NY, USA
| | - Natalia Dolzhanskaya
- New York State Institute for Basic Research in Developmental Disabilities, Staten Island, NY, USA
| | - Jacqueline Burré
- Appel Institute for Alzheimer's Disease Research, and Brain & Mind Research Institute, Weill Cornell Medicine, New York, NY, USA
| | - Milen T Velinov
- New York State Institute for Basic Research in Developmental Disabilities, Staten Island, NY, USA
| | - Manu Sharma
- Appel Institute for Alzheimer's Disease Research, and Brain & Mind Research Institute, Weill Cornell Medicine, New York, NY, USA.
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20
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Synaptotagmin 1 oligomers clamp and regulate different modes of neurotransmitter release. Proc Natl Acad Sci U S A 2020; 117:3819-3827. [PMID: 32015138 PMCID: PMC7035618 DOI: 10.1073/pnas.1920403117] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
Release of neurotransmitters relies on submillisecond coupling of synaptic vesicle fusion to the triggering signal: AP-evoked presynaptic Ca2+ influx. The key player that controls exocytosis of the synaptic vesicle is the Ca2+ sensor synaptotagmin 1 (Syt1). While the Ca2+ activation of Syt1 has been extensively characterized, how Syt1 reversibly clamps vesicular fusion remains enigmatic. Here, using a targeted mutation combined with fluorescence imaging and electrophysiology, we show that the structural feature of Syt1 to self-oligomerize provides the molecular basis for clamping of spontaneous and asynchronous release but is not required for triggering of synchronous release. Our findings propose a mechanistic model that explains how Syt1 oligomers regulate different modes of transmitter release in neuronal synapses. Synaptotagmin 1 (Syt1) synchronizes neurotransmitter release to action potentials (APs) acting as the fast Ca2+ release sensor and as the inhibitor (clamp) of spontaneous and delayed asynchronous release. While the Syt1 Ca2+ activation mechanism has been well-characterized, how Syt1 clamps transmitter release remains enigmatic. Here we show that C2B domain-dependent oligomerization provides the molecular basis for the Syt1 clamping function. This follows from the investigation of a designed mutation (F349A), which selectively destabilizes Syt1 oligomerization. Using a combination of fluorescence imaging and electrophysiology in neocortical synapses, we show that Syt1F349A is more efficient than wild-type Syt1 (Syt1WT) in triggering synchronous transmitter release but fails to clamp spontaneous and synaptotagmin 7 (Syt7)-mediated asynchronous release components both in rescue (Syt1−/− knockout background) and dominant-interference (Syt1+/+ background) conditions. Thus, we conclude that Ca2+-sensitive Syt1 oligomers, acting as an exocytosis clamp, are critical for maintaining the balance among the different modes of neurotransmitter release.
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21
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Trotter JH, Hao J, Maxeiner S, Tsetsenis T, Liu Z, Zhuang X, Südhof TC. Synaptic neurexin-1 assembles into dynamically regulated active zone nanoclusters. J Cell Biol 2019; 218:2677-2698. [PMID: 31262725 PMCID: PMC6683742 DOI: 10.1083/jcb.201812076] [Citation(s) in RCA: 59] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2018] [Revised: 05/10/2019] [Accepted: 05/30/2019] [Indexed: 12/04/2022] Open
Abstract
Neurexins are well-characterized presynaptic cell adhesion molecules that engage multifarious postsynaptic ligands and organize diverse synapse properties. However, the precise synaptic localization of neurexins remains enigmatic. Using super-resolution microscopy, we demonstrate that neurexin-1 forms discrete nanoclusters at excitatory synapses, revealing a novel organizational feature of synaptic architecture. Synapses generally contain a single nanocluster that comprises more than four neurexin-1 molecules and that also includes neurexin-2 and/or neurexin-3 isoforms. Moreover, we find that neurexin-1 is physiologically cleaved by ADAM10 similar to its ligand neuroligin-1, with ∼4-6% of neurexin-1 and ∼2-3% of neuroligin-1 present in the adult brain as soluble ectodomain proteins. Blocking ADAM10-mediated neurexin-1 cleavage dramatically increased the synaptic neurexin-1 content, thereby elevating the percentage of Homer1(+) excitatory synapses containing neurexin-1 nanoclusters from 40-50% to ∼80%, and doubling the number of neurexin-1 molecules per nanocluster. Taken together, our results reveal an unexpected nanodomain organization of synapses in which neurexin-1 is assembled into discrete presynaptic nanoclusters that are dynamically regulated via ectodomain cleavage.
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Affiliation(s)
- Justin H Trotter
- Department of Molecular and Cellular Physiology, Stanford University, Stanford, CA
- Howard Hughes Medical Institute, Stanford University, Stanford, CA
| | - Junjie Hao
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA
- Department of Physics, Harvard University, Cambridge, MA
- Howard Hughes Medical Institute, Harvard University, Cambridge, MA
| | - Stephan Maxeiner
- Department of Molecular and Cellular Physiology, Stanford University, Stanford, CA
- Howard Hughes Medical Institute, Stanford University, Stanford, CA
| | - Theodoros Tsetsenis
- Department of Molecular and Cellular Physiology, Stanford University, Stanford, CA
- Howard Hughes Medical Institute, Stanford University, Stanford, CA
| | - Zhihui Liu
- Department of Molecular and Cellular Physiology, Stanford University, Stanford, CA
- Howard Hughes Medical Institute, Stanford University, Stanford, CA
| | - Xiaowei Zhuang
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA
- Department of Physics, Harvard University, Cambridge, MA
- Howard Hughes Medical Institute, Harvard University, Cambridge, MA
| | - Thomas C Südhof
- Department of Molecular and Cellular Physiology, Stanford University, Stanford, CA
- Howard Hughes Medical Institute, Stanford University, Stanford, CA
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22
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Synaptotagmin-1 enables frequency coding by suppressing asynchronous release in a temperature dependent manner. Sci Rep 2019; 9:11341. [PMID: 31383906 PMCID: PMC6683208 DOI: 10.1038/s41598-019-47487-9] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2019] [Accepted: 07/17/2019] [Indexed: 01/08/2023] Open
Abstract
To support frequency-coded information transfer, mammalian synapses tightly synchronize neurotransmitter release to action potentials (APs). However, release desynchronizes during AP trains, especially at room temperature. Here we show that suppression of asynchronous release by Synaptotagmin-1 (Syt1), but not release triggering, is highly temperature sensitive, and enhances synchronous release during high-frequency stimulation. In Syt1-deficient synapses, asynchronous release increased with temperature, opposite to wildtype synapses. Mutations in Syt1 C2B-domain polybasic stretch (Syt1 K326Q,K327Q,K331Q) did not affect synchronization during sustained activity, while the previously observed reduced synchronous response to a single AP was confirmed. However, an inflexible linker between the C2-domains (Syt1 9Pro) reduced suppression, without affecting synchronous release upon a single AP. Syt1 9Pro expressing synapses showed impaired synchronization during AP trains, which was rescued by buffering global Ca2+ to prevent asynchronous release. Hence, frequency coding relies on Syt1's temperature sensitive suppression of asynchronous release, an aspect distinct from its known vesicle recruitment and triggering functions.
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23
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Specific factors in blood from young but not old mice directly promote synapse formation and NMDA-receptor recruitment. Proc Natl Acad Sci U S A 2019; 116:12524-12533. [PMID: 31160442 DOI: 10.1073/pnas.1902672116] [Citation(s) in RCA: 59] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Aging drives a progressive decline in cognition and decreases synapse numbers and synaptic function in the brain, thereby increasing the risk for neurodegenerative disease. Pioneering studies showed that introduction of blood from young mice into aged mice reversed age-associated cognitive impairments and increased synaptic connectivity in brain, suggesting that young blood contains specific factors that remediate age-associated decreases in brain function. However, whether such factors in blood from young animals act directly on neurons to enhance synaptic connectivity, or whether they act by an indirect mechanism remains unknown. Moreover, which factors in young blood mediate cognitive improvements in old mice is incompletely understood. Here, we show that serum extracted from the blood of young but not old mice, when applied to neurons transdifferentiated from human embryonic stem cells, directly increased dendritic arborization, augmented synapse numbers, doubled dendritic spine-like structures, and elevated synaptic N-methyl-d-aspartate (NMDA) receptors, thereby increasing synaptic connectivity. Mass spectrometry revealed that thrombospondin-4 (THBS4) and SPARC-like protein 1 (SPARCL1) were enriched in serum from young mice. Strikingly, recombinant THBS4 and SPARCL1 both increased dendritic arborization and doubled synapse numbers in cultured neurons. In addition, SPARCL1 but not THBS4 tripled NMDA receptor-mediated synaptic responses. Thus, at least two proteins enriched in young blood, THBS4 and SPARCL1, directly act on neurons as synaptogenic factors. These proteins may represent rejuvenation factors that enhance synaptic connectivity by increasing dendritic arborization, synapse formation, and synaptic transmission.
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24
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Sando R, Jiang X, Südhof TC. Latrophilin GPCRs direct synapse specificity by coincident binding of FLRTs and teneurins. Science 2019; 363:eaav7969. [PMID: 30792275 PMCID: PMC6636343 DOI: 10.1126/science.aav7969] [Citation(s) in RCA: 147] [Impact Index Per Article: 29.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2018] [Accepted: 01/15/2019] [Indexed: 12/16/2022]
Abstract
Bidirectional signaling by cell adhesion molecules is thought to mediate synapse formation, but the mechanisms involved remain elusive. We found that the adhesion G protein-coupled receptors latrophilin-2 and latrophilin-3 selectively direct formation of perforant-path and Schaffer-collateral synapses, respectively, to hippocampal CA1-region neurons. Latrophilin-3 binds to two transcellular ligands: fibronectin leucine-rich repeat transmembrane proteins (FLRTs) and teneurins. In transgenic mice in vivo, both binding activities were required for input-specific synapse formation, which suggests that coincident binding of both ligands is necessary for synapse formation. In cultured neurons in vitro, teneurin or FLRT alone did not induce excitatory synapse formation, whereas together they potently did so. Thus, postsynaptic latrophilins promote excitatory synapse formation by simultaneous binding of two unrelated presynaptic ligands, which is required for formation of synaptic inputs at specific dendritic localizations.
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Affiliation(s)
- Richard Sando
- Department of Molecular and Cellular Physiology and Howard Hughes Medical Institute, Stanford University Medical School, Stanford, CA 94305, USA
| | - Xian Jiang
- Department of Molecular and Cellular Physiology and Howard Hughes Medical Institute, Stanford University Medical School, Stanford, CA 94305, USA
| | - Thomas C Südhof
- Department of Molecular and Cellular Physiology and Howard Hughes Medical Institute, Stanford University Medical School, Stanford, CA 94305, USA.
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25
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Zhang L, Wei M, Shao L, Li M, Dai W, Cui Y, Li Z, Zhang C, Wang W. Enhanced parylene-C fluorescence as a visual marker for neuronal electrophysiology applications. LAB ON A CHIP 2018; 18:3539-3549. [PMID: 30406244 DOI: 10.1039/c8lc00804c] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Parylene-C is a popular polymer material in biomedical applications, with excellent physicochemical properties and microfabrication capability. Like many aromatic polymers, parylene-C also has autofluorescence, which was usually taken as a negative background noise in biomedical detection studies. However, the fluorescence intensity of thin-film (<1 μm) parylene-C was relatively weak, which may be a big limitation in visualization. In this work, we reported a simple annealing method to significantly enhance the fluorescence and achieve sufficient intensity as a visual marker. We studied the behaviors and mechanisms of the enhanced parylene-C fluorescence, then verified the feasibility and reliability of parylene-C for preparing fluorescent pipettes in targeted neuronal electrophysiology, where fluorescent guidance was strongly needed. The powerful parylene-C fabrication technique enables a precisely-controlled conformal coating along with a mass production capability, which further resulted in high-quality electrophysiological recordings of both cultured hippocampal neurons and acute hippocampal brain slices. Moreover, the enhanced parylene-C fluorescence can also be applied in more general biological operations, such as designable fluorescent micro-patterns for visualization in broader biomedical fields.
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Affiliation(s)
- Lingqian Zhang
- Institute of Microelectronics, Peking University, Beijing, 100871, China. and R&D Center of Healthcare Electronics, Institute of Microelectronics, Chinese Academy of Sciences, Beijing, 100029, China
| | - Mengping Wei
- Department of Neurobiology, Capital Medical University, Beijing, 100069, China and PKU-IDG/McGovern Institute for Brain Research, Peking University, Beijing, 100871, China.
| | - Linbo Shao
- School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138, USA
| | - Mingli Li
- Institute of molecular and medicine, Peking University, Beijing, 100871, China
| | - Wangzhi Dai
- Institute of Microelectronics, Peking University, Beijing, 100871, China.
| | - Yaxuan Cui
- PKU-IDG/McGovern Institute for Brain Research, Peking University, Beijing, 100871, China.
| | - Zhihong Li
- Institute of Microelectronics, Peking University, Beijing, 100871, China. and National Key Laboratory of Science and Technology on Micro/Nano Fabrication, Beijing, 100871, China
| | - Chen Zhang
- Department of Neurobiology, Capital Medical University, Beijing, 100069, China and PKU-IDG/McGovern Institute for Brain Research, Peking University, Beijing, 100871, China.
| | - Wei Wang
- Institute of Microelectronics, Peking University, Beijing, 100871, China. and National Key Laboratory of Science and Technology on Micro/Nano Fabrication, Beijing, 100871, China
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26
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Transdifferentiation of human adult peripheral blood T cells into neurons. Proc Natl Acad Sci U S A 2018; 115:6470-6475. [PMID: 29866841 DOI: 10.1073/pnas.1720273115] [Citation(s) in RCA: 60] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Human cell models for disease based on induced pluripotent stem (iPS) cells have proven to be powerful new assets for investigating disease mechanisms. New insights have been obtained studying single mutations using isogenic controls generated by gene targeting. Modeling complex, multigenetic traits using patient-derived iPS cells is much more challenging due to line-to-line variability and technical limitations of scaling to dozens or more patients. Induced neuronal (iN) cells reprogrammed directly from dermal fibroblasts or urinary epithelia could be obtained from many donors, but such donor cells are heterogeneous, show interindividual variability, and must be extensively expanded, which can introduce random mutations. Moreover, derivation of dermal fibroblasts requires invasive biopsies. Here we show that human adult peripheral blood mononuclear cells, as well as defined purified T lymphocytes, can be directly converted into fully functional iN cells, demonstrating that terminally differentiated human cells can be efficiently transdifferentiated into a distantly related lineage. T cell-derived iN cells, generated by nonintegrating gene delivery, showed stereotypical neuronal morphologies and expressed multiple pan-neuronal markers, fired action potentials, and were able to form functional synapses. These cells were stable in the absence of exogenous reprogramming factors. Small molecule addition and optimized culture systems have yielded conversion efficiencies of up to 6.2%, resulting in the generation of >50,000 iN cells from 1 mL of peripheral blood in a single step without the need for initial expansion. Thus, our method allows the generation of sufficient neurons for experimental interrogation from a defined, homogeneous, and readily accessible donor cell population.
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27
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de Jong APH, Roggero CM, Ho MR, Wong MY, Brautigam CA, Rizo J, Kaeser PS. RIM C 2B Domains Target Presynaptic Active Zone Functions to PIP 2-Containing Membranes. Neuron 2018; 98:335-349.e7. [PMID: 29606581 DOI: 10.1016/j.neuron.2018.03.011] [Citation(s) in RCA: 44] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2017] [Revised: 02/01/2018] [Accepted: 03/05/2018] [Indexed: 11/16/2022]
Abstract
Rapid and efficient synaptic vesicle fusion requires a pool of primed vesicles, the nearby tethering of Ca2+ channels, and the presence of the phospholipid PIP2 in the target membrane. Although the presynaptic active zone mediates the first two requirements, it is unclear how fusion is targeted to membranes with high PIP2 content. Here we find that the C2B domain of the active zone scaffold RIM is critical for action potential-triggered fusion. Remarkably, the known RIM functions in vesicle priming and Ca2+ influx do not require RIM C2B domains. Instead, biophysical experiments reveal that RIM C2 domains, which lack Ca2+ binding, specifically bind to PIP2. Mutational analyses establish that PIP2 binding to RIM C2B and its tethering to the other RIM domains are crucial for efficient exocytosis. We propose that RIM C2B domains are constitutive PIP2-binding modules that couple mechanisms for vesicle priming and Ca2+ channel tethering to PIP2-containing target membranes.
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Affiliation(s)
- Arthur P H de Jong
- Department of Neurobiology, Harvard Medical School, Boston, MA 02115, USA
| | - Carlos M Roggero
- Departments of Biophysics, Biochemistry, and Pharmacology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Meng-Ru Ho
- Departments of Biophysics, Biochemistry, and Pharmacology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA; Institute of Biological Chemistry, Academia Sinica, Taipei, Taiwan
| | - Man Yan Wong
- Department of Neurobiology, Harvard Medical School, Boston, MA 02115, USA
| | - Chad A Brautigam
- Departments of Biophysics and Microbiology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Josep Rizo
- Departments of Biophysics, Biochemistry, and Pharmacology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Pascal S Kaeser
- Department of Neurobiology, Harvard Medical School, Boston, MA 02115, USA.
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28
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Hirabayashi Y, Kwon SK, Paek H, Pernice WM, Paul MA, Lee J, Erfani P, Raczkowski A, Petrey DS, Pon LA, Polleux F. ER-mitochondria tethering by PDZD8 regulates Ca 2+ dynamics in mammalian neurons. Science 2018; 358:623-630. [PMID: 29097544 DOI: 10.1126/science.aan6009] [Citation(s) in RCA: 315] [Impact Index Per Article: 52.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2017] [Revised: 08/21/2017] [Accepted: 09/20/2017] [Indexed: 01/06/2023]
Abstract
Interfaces between organelles are emerging as critical platforms for many biological responses in eukaryotic cells. In yeast, the ERMES complex is an endoplasmic reticulum (ER)-mitochondria tether composed of four proteins, three of which contain a SMP (synaptotagmin-like mitochondrial-lipid binding protein) domain. No functional ortholog for any ERMES protein has been identified in metazoans. Here, we identified PDZD8 as an ER protein present at ER-mitochondria contacts. The SMP domain of PDZD8 is functionally orthologous to the SMP domain found in yeast Mmm1. PDZD8 was necessary for the formation of ER-mitochondria contacts in mammalian cells. In neurons, PDZD8 was required for calcium ion (Ca2+) uptake by mitochondria after synaptically induced Ca2+-release from ER and thereby regulated cytoplasmic Ca2+ dynamics. Thus, PDZD8 represents a critical ER-mitochondria tethering protein in metazoans. We suggest that ER-mitochondria coupling is involved in the regulation of dendritic Ca2+ dynamics in mammalian neurons.
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Affiliation(s)
- Yusuke Hirabayashi
- Department of Neuroscience, Columbia University Medical Center, Columbia University, New York, NY 10027, USA.,Mortimer B. Zuckerman Mind Brain Behavior Institute, Columbia University, New York, NY 10027, USA.,Kavli Institute for Brain Science, Columbia University, New York, NY 10027, USA.,Japan Science and Technology Agency (JST), Precursory Research for Embryonic Science and Technology (PRESTO), Tokyo, Japan
| | - Seok-Kyu Kwon
- Department of Neuroscience, Columbia University Medical Center, Columbia University, New York, NY 10027, USA.,Mortimer B. Zuckerman Mind Brain Behavior Institute, Columbia University, New York, NY 10027, USA.,Kavli Institute for Brain Science, Columbia University, New York, NY 10027, USA
| | - Hunki Paek
- Department of Neuroscience, Columbia University Medical Center, Columbia University, New York, NY 10027, USA.,Mortimer B. Zuckerman Mind Brain Behavior Institute, Columbia University, New York, NY 10027, USA.,Kavli Institute for Brain Science, Columbia University, New York, NY 10027, USA
| | - Wolfgang M Pernice
- Department of Pathology and Cell Biology, Columbia University, New York, NY 10032, USA
| | - Maëla A Paul
- Department of Neuroscience, Columbia University Medical Center, Columbia University, New York, NY 10027, USA.,Mortimer B. Zuckerman Mind Brain Behavior Institute, Columbia University, New York, NY 10027, USA.,Kavli Institute for Brain Science, Columbia University, New York, NY 10027, USA
| | - Jinoh Lee
- Department of Neuroscience, Columbia University Medical Center, Columbia University, New York, NY 10027, USA.,Mortimer B. Zuckerman Mind Brain Behavior Institute, Columbia University, New York, NY 10027, USA.,Kavli Institute for Brain Science, Columbia University, New York, NY 10027, USA
| | - Parsa Erfani
- Department of Neuroscience, Columbia University Medical Center, Columbia University, New York, NY 10027, USA.,Mortimer B. Zuckerman Mind Brain Behavior Institute, Columbia University, New York, NY 10027, USA.,Kavli Institute for Brain Science, Columbia University, New York, NY 10027, USA
| | - Ashleigh Raczkowski
- Simons Electron Microscopy Center, New York Structural Biology Center (NYSBC), New York, NY 10027, USA
| | - Donald S Petrey
- Center for Computational Biology and Bioinformatics, Department of Systems Biology, Columbia University, New York, NY 10032, USA.,Howard Hughes Medical Institute, Columbia University, New York, NY 10032, USA
| | - Liza A Pon
- Department of Pathology and Cell Biology, Columbia University, New York, NY 10032, USA.,Institute of Human Nutrition, Columbia University, New York, NY 10032, USA
| | - Franck Polleux
- Department of Neuroscience, Columbia University Medical Center, Columbia University, New York, NY 10027, USA. .,Mortimer B. Zuckerman Mind Brain Behavior Institute, Columbia University, New York, NY 10027, USA.,Kavli Institute for Brain Science, Columbia University, New York, NY 10027, USA
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Intellicount: High-Throughput Quantification of Fluorescent Synaptic Protein Puncta by Machine Learning. eNeuro 2017; 4:eN-MNT-0219-17. [PMID: 29218324 PMCID: PMC5718246 DOI: 10.1523/eneuro.0219-17.2017] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2017] [Revised: 10/18/2017] [Accepted: 11/06/2017] [Indexed: 01/07/2023] Open
Abstract
Synapse formation analyses can be performed by imaging and quantifying fluorescent signals of synaptic markers. Traditionally, these analyses are done using simple or multiple thresholding and segmentation approaches or by labor-intensive manual analysis by a human observer. Here, we describe Intellicount, a high-throughput, fully-automated synapse quantification program which applies a novel machine learning (ML)-based image processing algorithm to systematically improve region of interest (ROI) identification over simple thresholding techniques. Through processing large datasets from both human and mouse neurons, we demonstrate that this approach allows image processing to proceed independently of carefully set thresholds, thus reducing the need for human intervention. As a result, this method can efficiently and accurately process large image datasets with minimal interaction by the experimenter, making it less prone to bias and less liable to human error. Furthermore, Intellicount is integrated into an intuitive graphical user interface (GUI) that provides a set of valuable features, including automated and multifunctional figure generation, routine statistical analyses, and the ability to run full datasets through nested folders, greatly expediting the data analysis process.
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Use-dependent potentiation of voltage-gated calcium channels rescues neurotransmission in nerve terminals intoxicated by botulinum neurotoxin serotype A. Sci Rep 2017; 7:15862. [PMID: 29158500 PMCID: PMC5696531 DOI: 10.1038/s41598-017-16064-3] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2017] [Accepted: 11/06/2017] [Indexed: 01/27/2023] Open
Abstract
Botulinum neurotoxins (BoNTs) are highly potent toxins that cleave neuronal SNARE proteins required for neurotransmission, causing flaccid paralysis and death by asphyxiation. Currently, there are no clinical treatments to delay or reverse BoNT-induced blockade of neuromuscular transmission. While aminopyridines have demonstrated varying efficacy in transiently reducing paralysis following BoNT poisoning, the precise mechanisms by which aminopyridines symptomatically treat botulism are not understood. Here we found that activity-dependent potentiation of presynaptic voltage-gated calcium channels (VGCCs) underlies 3,4-diaminopyridine (3,4-DAP)-mediated rescue of neurotransmission in central nervous system synapses and mouse diaphragm neuromuscular junctions fully intoxicated by BoNT serotype A. Combinatorial treatments with 3,4-DAP and VGCC agonists proved synergistic in restoring suprathreshold endplate potentials in mouse diaphragms fully intoxicated by BoNT/A. In contrast, synapses fully intoxicated by BoNT serotypes D or E were refractory to synaptic rescue by any treatment. We interpret these data to propose that increasing the duration or extent of VGCC activation prolongs the opportunity for low-efficiency fusion by fusogenic complexes incorporating BoNT/A-cleaved SNAP-25. The identification of VGCC agonists that rescue neurotransmission in BoNT/A-intoxicated synapses provides compelling evidence for potential therapeutic utility in some cases of human botulism.
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31
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Anderson GR, Maxeiner S, Sando R, Tsetsenis T, Malenka RC, Südhof TC. Postsynaptic adhesion GPCR latrophilin-2 mediates target recognition in entorhinal-hippocampal synapse assembly. J Cell Biol 2017; 216:3831-3846. [PMID: 28972101 PMCID: PMC5674891 DOI: 10.1083/jcb.201703042] [Citation(s) in RCA: 68] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2017] [Revised: 07/24/2017] [Accepted: 08/17/2017] [Indexed: 12/15/2022] Open
Abstract
Synapse assembly likely requires postsynaptic target recognition by incoming presynaptic afferents. Using newly generated conditional knock-in and knockout mice, we show in this study that latrophilin-2 (Lphn2), a cell-adhesion G protein-coupled receptor and presumptive α-latrotoxin receptor, controls the numbers of a specific subset of synapses in CA1-region hippocampal neurons, suggesting that Lphn2 acts as a synaptic target-recognition molecule. In cultured hippocampal neurons, Lphn2 maintained synapse numbers via a postsynaptic instead of a presynaptic mechanism, which was surprising given its presumptive role as an α-latrotoxin receptor. In CA1-region neurons in vivo, Lphn2 was specifically targeted to dendritic spines in the stratum lacunosum-moleculare, which form synapses with presynaptic entorhinal cortex afferents. In this study, postsynaptic deletion of Lphn2 selectively decreased spine numbers and impaired synaptic inputs from entorhinal but not Schaffer-collateral afferents. Behaviorally, loss of Lphn2 from the CA1 region increased spatial memory retention but decreased learning of sequential spatial memory tasks. Thus, Lphn2 appears to control synapse numbers in the entorhinal cortex/CA1 region circuit by acting as a domain-specific postsynaptic target-recognition molecule.
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MESH Headings
- Animals
- Behavior, Animal
- CA1 Region, Hippocampal/metabolism
- CA1 Region, Hippocampal/pathology
- CA1 Region, Hippocampal/physiopathology
- Cells, Cultured
- Dendritic Spines/metabolism
- Dendritic Spines/pathology
- Entorhinal Cortex/metabolism
- Entorhinal Cortex/pathology
- Entorhinal Cortex/physiopathology
- Fear
- Genotype
- Maze Learning
- Memory
- Mice, Mutant Strains
- Motor Activity
- Neurons/metabolism
- Neurons/pathology
- Phenotype
- Presynaptic Terminals/metabolism
- Presynaptic Terminals/pathology
- Receptors, G-Protein-Coupled/genetics
- Receptors, G-Protein-Coupled/metabolism
- Receptors, Peptide/genetics
- Receptors, Peptide/metabolism
- Rotarod Performance Test
- Smell
- Synaptic Membranes/metabolism
- Synaptic Membranes/pathology
- Synaptic Potentials
- Time Factors
- Transfection
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Affiliation(s)
- Garret R Anderson
- Department of Molecular and Cellular Physiology, Howard Hughes Medical Institute, Stanford University Medical School, Stanford, CA
- Department of Psychiatry and Behavioral Science, Nancy Pritzker Laboratory, Stanford University Medical School, Stanford, CA
| | - Stephan Maxeiner
- Department of Molecular and Cellular Physiology, Howard Hughes Medical Institute, Stanford University Medical School, Stanford, CA
| | - Richard Sando
- Department of Molecular and Cellular Physiology, Howard Hughes Medical Institute, Stanford University Medical School, Stanford, CA
| | - Theodoros Tsetsenis
- Department of Molecular and Cellular Physiology, Howard Hughes Medical Institute, Stanford University Medical School, Stanford, CA
| | - Robert C Malenka
- Department of Psychiatry and Behavioral Science, Nancy Pritzker Laboratory, Stanford University Medical School, Stanford, CA
| | - Thomas C Südhof
- Department of Molecular and Cellular Physiology, Howard Hughes Medical Institute, Stanford University Medical School, Stanford, CA
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32
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Dissecting the Role of Synaptic Proteins with CRISPR. ACTA ACUST UNITED AC 2017. [DOI: 10.1007/978-3-319-60192-2_5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
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33
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Identification of Protein Tyrosine Phosphatase Receptor Type O (PTPRO) as a Synaptic Adhesion Molecule that Promotes Synapse Formation. J Neurosci 2017; 37:9828-9843. [PMID: 28871037 DOI: 10.1523/jneurosci.0729-17.2017] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2017] [Revised: 07/26/2017] [Accepted: 08/22/2017] [Indexed: 01/07/2023] Open
Abstract
The proper formation of synapses-specialized unitary structures formed between two neurons-is critical to mediating information flow in the brain. Synaptic cell adhesion molecules (CAMs) are thought to participate in the initiation of the synapse formation process. However, in vivo functional analysis demonstrates that most well known synaptic CAMs regulate synaptic maturation and plasticity rather than synapse formation, suggesting that either CAMs work synergistically in the process of forming synapses or more CAMs remain to be found. By screening for unknown CAMs using a co-culture system, we revealed that protein tyrosine phosphatase receptor type O (PTPRO) is a potent CAM that induces the formation of artificial synapse clusters in co-cultures of human embryonic kidney 293 cells and hippocampal neurons cultured from newborn mice regardless of gender. PTPRO was enriched in the mouse brain and localized to postsynaptic sites at excitatory synapses. The overexpression of PTPRO in cultured hippocampal neurons increased the number of synapses and the frequency of miniature EPSCs (mEPSCs). The knock-down (KD) of PTPRO expression in cultured neurons by short hairpin RNA (shRNA) reduced the number of synapses and the frequencies of the mEPSCs. The effects of shRNA KD were rescued by expressing either full-length PTPRO or a truncated PTPRO lacking the cytoplasmic domain. Consistent with these results, the N-terminal extracellular domain of PTPRO was required for its synaptogenic activity in the co-culture assay. Our data show that PTPRO is a synaptic CAM that serves as a potent initiator of the formation of excitatory synapses.SIGNIFICANCE STATEMENT The formation of synapses is critical for the brain to execute its function and synaptic cell adhesion molecules (CAMs) play essential roles in initiating the formation of synapses. By screening for unknown CAMs using a co-culture system, we revealed that protein tyrosine phosphatase receptor type O (PTPRO) is a potent CAM that induces the formation of artificial synapse clusters. Using loss-of-function and gain-of-function approaches, we show that PTPRO promotes the formation of excitatory synapses. The N-terminal extracellular domain of PTPRO was required for its synaptogenic activity in cultured hippocampal neurons and the co-culture assay. Together, our data show that PTPRO is a synaptic CAM that serves as a potent initiator of synapse formation.
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34
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The primed SNARE-complexin-synaptotagmin complex for neuronal exocytosis. Nature 2017; 548:420-425. [PMID: 28813412 DOI: 10.1038/nature23484] [Citation(s) in RCA: 194] [Impact Index Per Article: 27.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2017] [Accepted: 07/14/2017] [Indexed: 12/17/2022]
Abstract
Synaptotagmin, complexin, and neuronal SNARE (soluble N-ethylmaleimide sensitive factor attachment protein receptor) proteins mediate evoked synchronous neurotransmitter release, but the molecular mechanisms mediating the cooperation between these molecules remain unclear. Here we determine crystal structures of the primed pre-fusion SNARE-complexin-synaptotagmin-1 complex. These structures reveal an unexpected tripartite interface between synaptotagmin-1 and both the SNARE complex and complexin. Simultaneously, a second synaptotagmin-1 molecule interacts with the other side of the SNARE complex via the previously identified primary interface. Mutations that disrupt either interface in solution also severely impair evoked synchronous release in neurons, suggesting that both interfaces are essential for the primed pre-fusion state. Ca2+ binding to the synaptotagmin-1 molecules unlocks the complex, allows full zippering of the SNARE complex, and triggers membrane fusion. The tripartite SNARE-complexin-synaptotagmin-1 complex at a synaptic vesicle docking site has to be unlocked for triggered fusion to start, explaining the cooperation between complexin and synaptotagmin-1 in synchronizing evoked release on the sub-millisecond timescale.
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35
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Synapsin Isoforms Regulating GABA Release from Hippocampal Interneurons. J Neurosci 2017; 36:6742-57. [PMID: 27335405 DOI: 10.1523/jneurosci.0011-16.2016] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2016] [Accepted: 05/13/2016] [Indexed: 01/02/2023] Open
Abstract
UNLABELLED Although synapsins regulate GABA release, it is unclear which synapsin isoforms are involved. We identified the synapsin isoforms that regulate GABA release via rescue experiments in cultured hippocampal neurons from synapsin I, II, and III triple knock-out (TKO) mice. In situ hybridization indicated that five different synapsin isoforms are expressed in hippocampal interneurons. Evoked IPSC amplitude was reduced in TKO neurons compared with triple wild-type neurons and was rescued by introducing any of the five synapsin isoforms. This contrasts with hippocampal glutamatergic terminals, where only synapsin IIa rescues the TKO phenotype. Deconvolution analysis indicated that the duration of GABA release was prolonged in TKO neurons and this defect in release kinetics was rescued by each synapsin isoform, aside from synapsin IIIa. Because release kinetics remained slow, whereas peak release rate was rescued, there was a 2-fold increase in GABA release in TKO neurons expressing synapsin IIIa. TKO neurons expressing individual synapsin isoforms showed normal depression kinetics aside from more rapid depression in neurons expressing synapsin IIIa. Measurements of the cumulative amount of GABA released during repetitive stimulation revealed that the rate of mobilization of vesicles from the reserve pool to the readily releasable pool and the size of the readily releasable pool of GABAergic vesicles were unaffected by synapsins. Instead, synapsins regulate release of GABA from the readily releasable pool, with all isoforms aside from synapsin IIIa controlling release synchrony. These results indicate that synapsins play fundamentally distinct roles at different types of presynaptic terminals. SIGNIFICANCE STATEMENT Synapsins are a family of proteins that regulate synaptic vesicle (SV) trafficking within nerve terminals. Here, we demonstrate that release of the inhibitory neurotransmitter GABA is supported by many different synapsin types. This contrasts with the release of other neurotransmitters, which typically is supported by only one type of synapsin. We also found that synapsins serve to synchronize the release of GABA in response to presynaptic action potentials, which is different from the synapsin-dependent trafficking of SVs in other nerve terminals. Our results establish that different synapsins play fundamentally different roles at nerve terminals releasing different types of neurotransmitters. This is an important clue to understanding how neurons release their neurotransmitters, a process essential for normal brain function.
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36
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Unique versus Redundant Functions of Neuroligin Genes in Shaping Excitatory and Inhibitory Synapse Properties. J Neurosci 2017; 37:6816-6836. [PMID: 28607166 DOI: 10.1523/jneurosci.0125-17.2017] [Citation(s) in RCA: 69] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2017] [Revised: 05/10/2017] [Accepted: 05/31/2017] [Indexed: 11/21/2022] Open
Abstract
Neuroligins are evolutionarily conserved postsynaptic cell adhesion molecules that interact with presynaptic neurexins. Neurons express multiple neuroligin isoforms that are targeted to specific synapses, but their synaptic functions and mechanistic redundancy are not completely understood. Overexpression or RNAi-mediated knockdown of neuroligins, respectively, causes a dramatic increase or decrease in synapse density, whereas genetic deletions of neuroligins impair synapse function with only minor effects on synapse numbers, raising fundamental questions about the overall physiological role of neuroligins. Here, we have systematically analyzed the effects of conditional genetic deletions of all major neuroligin isoforms (i.e., NL1, NL2, and NL3), either individually or in combinations, in cultured mouse hippocampal and cortical neurons. We found that conditional genetic deletions of neuroligins caused no change or only a small change in synapses numbers, but strongly impaired synapse function. This impairment was isoform specific, suggesting that neuroligins are not functionally redundant. Sparse neuroligin deletions produced phenotypes comparable to those of global deletions, indicating that neuroligins function in a cell-autonomous manner. Mechanistically, neuroligin deletions decreased the synaptic levels of neurotransmitter receptors and had no effect on presynaptic release probabilities. Overexpression of neuroligin-1 in control or neuroligin-deficient neurons increased synaptic transmission and synapse density but not spine numbers, suggesting that these effects reflect a gain-of-function mechanism; whereas overexpression of neuroligin-3, which, like neuroligin-1 is also targeted to excitatory synapses, had no comparable effect. Our data demonstrate that neuroligins are required for the physiological organization of neurotransmitter receptors in postsynaptic specializations and suggest that they do not play a major role in synapse formation.SIGNIFICANCE STATEMENT Human neuroligin genes have been associated with autism, but the cellular functions of different neuroligins and their molecular mechanisms remain incompletely understood. Here, we performed comparative analyses in cultured mouse neurons of all major neuroligin isoforms, either individually or in combinations, using conditional knockouts. We found that neuroligin deletions did not affect synapse numbers but differentially impaired excitatory or inhibitory synaptic functions in an isoform-specific manner. These impairments were due, at least in part, to a decrease in synaptic distribution of neurotransmitter receptors upon deletion of neuroligins. Conversely, the overexpression of neuroligin-1 increased synapse numbers but not spine numbers. Our results suggest that various neuroligin isoforms perform unique postsynaptic functions in organizing synapses but are not essential for synapse formation or maintenance.
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37
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Xu J, Kurup P, Nairn AC, Lombroso PJ. Synaptic NMDA Receptor Activation Induces Ubiquitination and Degradation of STEP 61. Mol Neurobiol 2017; 55:3096-3111. [PMID: 28466270 DOI: 10.1007/s12035-017-0555-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2016] [Accepted: 04/12/2017] [Indexed: 01/25/2023]
Abstract
NMDA receptor signaling is critical for the development of synaptic plasticity, learning, and memory, and dysregulation of NMDAR signaling is implicated in a number of neurological disorders including schizophrenia (SZ). Previous work has demonstrated that the STriatal-Enriched protein tyrosine Phosphatase 61 kDa (STEP61) is elevated in human SZ postmortem cortical samples and after administration of psychotomimetics to cultures or mice. Here, we report that activation of synaptic NMDAR by bicuculline or D-serine results in the ubiquitination and proteasomal degradation of STEP61, and increased surface localization of GluN1/GluN2B receptors. Moreover, bicuculline or D-serine treatments rescue the motor and cognitive deficits in MK-801-treated mice and reduce STEP61 in mouse frontal cortex. These results suggest that STEP61 may contribute to the therapeutic effects of D-serine.
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Affiliation(s)
- Jian Xu
- Child Study Center, Yale University School of Medicine, New Haven, USA
| | - Pradeep Kurup
- Child Study Center, Yale University School of Medicine, New Haven, USA
| | - Angus C Nairn
- Department of Psychiatry, Yale University School of Medicine, New Haven, USA
| | - Paul J Lombroso
- Child Study Center, Yale University School of Medicine, New Haven, USA. .,Department of Psychiatry, Yale University School of Medicine, New Haven, USA. .,Department of Neurobiology, Yale University School of Medicine, New Haven, USA.
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38
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Mall M, Kareta MS, Chanda S, Ahlenius H, Perotti N, Zhou B, Grieder SD, Ge X, Drake S, Ang CE, Walker BM, Vierbuchen T, Fuentes DR, Brennecke P, Nitta KR, Jolma A, Steinmetz LM, Taipale J, Südhof TC, Wernig M. Myt1l safeguards neuronal identity by actively repressing many non-neuronal fates. Nature 2017; 544:245-249. [PMID: 28379941 PMCID: PMC11348803 DOI: 10.1038/nature21722] [Citation(s) in RCA: 151] [Impact Index Per Article: 21.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2015] [Accepted: 02/23/2017] [Indexed: 12/18/2022]
Abstract
Normal differentiation and induced reprogramming require the activation of target cell programs and silencing of donor cell programs. In reprogramming, the same factors are often used to reprogram many different donor cell types. As most developmental repressors, such as RE1-silencing transcription factor (REST) and Groucho (also known as TLE), are considered lineage-specific repressors, it remains unclear how identical combinations of transcription factors can silence so many different donor programs. Distinct lineage repressors would have to be induced in different donor cell types. Here, by studying the reprogramming of mouse fibroblasts to neurons, we found that the pan neuron-specific transcription factor Myt1-like (Myt1l) exerts its pro-neuronal function by direct repression of many different somatic lineage programs except the neuronal program. The repressive function of Myt1l is mediated via recruitment of a complex containing Sin3b by binding to a previously uncharacterized N-terminal domain. In agreement with its repressive function, the genomic binding sites of Myt1l are similar in neurons and fibroblasts and are preferentially in an open chromatin configuration. The Notch signalling pathway is repressed by Myt1l through silencing of several members, including Hes1. Acute knockdown of Myt1l in the developing mouse brain mimicked a Notch gain-of-function phenotype, suggesting that Myt1l allows newborn neurons to escape Notch activation during normal development. Depletion of Myt1l in primary postmitotic neurons de-repressed non-neuronal programs and impaired neuronal gene expression and function, indicating that many somatic lineage programs are actively and persistently repressed by Myt1l to maintain neuronal identity. It is now tempting to speculate that similar 'many-but-one' lineage repressors exist for other cell fates; such repressors, in combination with lineage-specific activators, would be prime candidates for use in reprogramming additional cell types.
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Affiliation(s)
- Moritz Mall
- Department of Pathology and Institute for Stem Cell Biology and Regenerative Medicine
| | - Michael S. Kareta
- Department of Pathology and Institute for Stem Cell Biology and Regenerative Medicine
- Current Address: Children’s Health Research Center, Sanford Research, Sioux Falls, SD 57104, USA
| | - Soham Chanda
- Department of Pathology and Institute for Stem Cell Biology and Regenerative Medicine
- Department of Molecular and Cellular Physiology and Howard Hughes Medical Institute
| | | | - Nicholas Perotti
- Department of Pathology and Institute for Stem Cell Biology and Regenerative Medicine
| | - Bo Zhou
- Department of Pathology and Institute for Stem Cell Biology and Regenerative Medicine
- Department of Molecular and Cellular Physiology and Howard Hughes Medical Institute
| | - Sarah D. Grieder
- Department of Pathology and Institute for Stem Cell Biology and Regenerative Medicine
| | - Xuecai Ge
- Department of Developmental Biology, Stanford University, Stanford, CA 94305, USA
- Current Address: Molecular and Cellular Biology, University of California Merced, Merced, CA 95343, USA
| | - Sienna Drake
- Lund Stem Cell Center, Lund University, 221 84 Lund, Sweden
| | - Cheen Euong Ang
- Department of Pathology and Institute for Stem Cell Biology and Regenerative Medicine
| | - Brandon M. Walker
- Department of Pathology and Institute for Stem Cell Biology and Regenerative Medicine
| | - Thomas Vierbuchen
- Department of Pathology and Institute for Stem Cell Biology and Regenerative Medicine
| | - Daniel R. Fuentes
- Department of Pathology and Institute for Stem Cell Biology and Regenerative Medicine
| | - Philip Brennecke
- Department of Genetics
- Current Address: Leibniz-Institute for Molecular Pharmacology, 13125 Berlin, Germany
| | - Kazuhiro R. Nitta
- Division of Functional Genomics and Systems Biology, Department of Medical Biochemistry and Biophysics, Karolinska Institutet, 171 77 Stockholm, Sweden
- Current Address: Division of Genomic Technologies, RIKEN Center for Life Science Technologies, Yokohama 230-0045, Japan
| | - Arttu Jolma
- Division of Functional Genomics and Systems Biology, Department of Medical Biochemistry and Biophysics, Karolinska Institutet, 171 77 Stockholm, Sweden
| | - Lars M. Steinmetz
- Department of Genetics
- Genome Biology Unit, European Molecular Biology Laboratory (EMBL), 69117 Heidelberg, Germany
| | - Jussi Taipale
- Division of Functional Genomics and Systems Biology, Department of Medical Biochemistry and Biophysics, Karolinska Institutet, 171 77 Stockholm, Sweden
- Genome Scale Biology Program, University of Helsinki, 00014 Helsinki, Finland
| | - Thomas C. Südhof
- Department of Molecular and Cellular Physiology and Howard Hughes Medical Institute
| | - Marius Wernig
- Department of Pathology and Institute for Stem Cell Biology and Regenerative Medicine
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39
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Wu D, Bacaj T, Morishita W, Goswami D, Arendt KL, Xu W, Chen L, Malenka RC, Südhof TC. Postsynaptic synaptotagmins mediate AMPA receptor exocytosis during LTP. Nature 2017; 544:316-321. [PMID: 28355182 PMCID: PMC5734942 DOI: 10.1038/nature21720] [Citation(s) in RCA: 132] [Impact Index Per Article: 18.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2016] [Accepted: 02/22/2017] [Indexed: 12/19/2022]
Abstract
Strengthening of synaptic connections by NMDA-receptor-dependent long-term potentiation (LTP) shapes neural circuits and mediates learning and memory. During NMDA-receptor-dependent LTP induction, Ca2+-influx stimulates recruitment of synaptic AMPA-receptors, thereby strengthening synapses. How Ca2+ induces AMPA-receptor recruitment, however, remains unclear. Here we show that, in pyramidal neurons of the hippocampal CA1-region, blocking postsynaptic expression of both synaptotagmin-1 and synaptotagmin-7, but not of synaptotagmin-1 or synaptotagmin-7 alone, abolished LTP. LTP was rescued by wild-type but not by Ca2+-binding-deficient mutant synaptotagmin-7. Blocking postsynaptic synaptotagmin-1/7 expression did not impair basal synaptic transmission, synaptic or extrasynaptic AMPA-receptor levels, or other AMPA-receptor trafficking events. Moreover, expression of dominant-negative mutant synaptotagmin-1 that inhibited Ca2+-dependent presynaptic vesicle exocytosis also blocked Ca2+-dependent postsynaptic AMPA-receptor exocytosis, thereby abolishing LTP. Our results suggest that postsynaptic synaptotagmin-1 and synaptotagmin-7 act as redundant Ca2+-sensors for Ca2+-dependent exocytosis of AMPA-receptors during LTP, thus delineating a simple mechanism for the recruitment of AMPA-receptors that mediates LTP.
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Affiliation(s)
- Dick Wu
- Department of Molecular &Cellular Physiology and Howard Hughes Medical Institute, Stanford University Medical School, Stanford, California 94305, USA.,Nancy Pritzker Laboratory, Stanford University Medical School, Stanford, California 94305, USA.,Department of Psychiatry &Behavioral Sciences, Stanford University Medical School, Stanford, California 94305, USA
| | - Taulant Bacaj
- Department of Molecular &Cellular Physiology and Howard Hughes Medical Institute, Stanford University Medical School, Stanford, California 94305, USA
| | - Wade Morishita
- Nancy Pritzker Laboratory, Stanford University Medical School, Stanford, California 94305, USA.,Department of Psychiatry &Behavioral Sciences, Stanford University Medical School, Stanford, California 94305, USA
| | - Debanjan Goswami
- Nancy Pritzker Laboratory, Stanford University Medical School, Stanford, California 94305, USA.,Department of Psychiatry &Behavioral Sciences, Stanford University Medical School, Stanford, California 94305, USA
| | - Kristin L Arendt
- Department of Neurosurgery, Stanford University Medical School, Stanford, California 94305, USA
| | - Wei Xu
- Department of Molecular &Cellular Physiology and Howard Hughes Medical Institute, Stanford University Medical School, Stanford, California 94305, USA
| | - Lu Chen
- Department of Neurosurgery, Stanford University Medical School, Stanford, California 94305, USA
| | - Robert C Malenka
- Nancy Pritzker Laboratory, Stanford University Medical School, Stanford, California 94305, USA.,Department of Psychiatry &Behavioral Sciences, Stanford University Medical School, Stanford, California 94305, USA
| | - Thomas C Südhof
- Department of Molecular &Cellular Physiology and Howard Hughes Medical Institute, Stanford University Medical School, Stanford, California 94305, USA
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40
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Liu T, Li H, Hong W, Han W. Brefeldin A-inhibited guanine nucleotide exchange protein 3 is localized in lysosomes and regulates GABA signaling in hippocampal neurons. J Neurochem 2016; 139:748-756. [PMID: 27696409 DOI: 10.1111/jnc.13859] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2016] [Revised: 09/14/2016] [Accepted: 09/22/2016] [Indexed: 01/06/2023]
Abstract
ADP-ribosylation factor (ARF) family of guanine-nucleotide-binding (G) proteins regulates organelle biogenesis, structure and trafficking. The functions of ARF proteins are tightly controlled by guanine nucleotide exchange factors (GEFs) containing a conserved SEC7 domain. Based on sequence similarity to brefeldin A-inhibited guanine nucleotide exchange protein (BIG)/GBF of the Arf-GEF family, we recently identified BIG3 as a novel ARF GEF protein with a non-functional catalytic motif in the SEC7 domain. BIG3 is mainly expressed in pancreatic islets and brain. In the islets, depletion of BIG3 increases insulin and glucagon secretion because of enhanced biogenesis of insulin and glucagon granules in the absence of BIG3. Here, we investigate BIG3 functions in the brain, in particular its regulation of neurotransmitter release in hippocampal neurons from wild-type and BIG3 knockout mice. In hippocampal neurons, BIG3 is mainly localized in lysosomes, and its depletion selectively impairs inhibitory synaptic transmission. Our finding provides novel insights for a cell-specific function of BIG3 in regulating neurotransmission.
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Affiliation(s)
- Tao Liu
- Singapore Bioimaging Consortium, Agency for Science, Technology and Research (A*STAR), Singapore
| | - Hongyu Li
- Singapore Bioimaging Consortium, Agency for Science, Technology and Research (A*STAR), Singapore
| | - Wanjin Hong
- Institute of Molecular and Cell Biology, Agency for Science, Technology and Research (A*STAR), Singapore
| | - Weiping Han
- Singapore Bioimaging Consortium, Agency for Science, Technology and Research (A*STAR), Singapore
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Oni EN, Halikere A, Li G, Toro-Ramos AJ, Swerdel MR, Verpeut JL, Moore JC, Bello NT, Bierut LJ, Goate A, Tischfield JA, Pang ZP, Hart RP. Increased nicotine response in iPSC-derived human neurons carrying the CHRNA5 N398 allele. Sci Rep 2016; 6:34341. [PMID: 27698409 PMCID: PMC5048107 DOI: 10.1038/srep34341] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2016] [Accepted: 09/12/2016] [Indexed: 12/12/2022] Open
Abstract
Genetic variation in nicotinic receptor alpha 5 (CHRNA5) has been associated with increased risk of addiction-associated phenotypes in humans yet little is known the underlying neural basis. Induced pluripotent stem cells (iPSCs) were derived from donors homozygous for either the major (D398) or the minor (N398) allele of the nonsynonymous single nucleotide polymorphism (SNP), rs16969968, in CHRNA5. To understand the impact of these nicotinic receptor variants in humans, we differentiated these iPSCs to dopamine (DA) or glutamatergic neurons and then tested their functional properties and response to nicotine. Results show that N398 variant human DA neurons differentially express genes associated with ligand receptor interaction and synaptic function. While both variants exhibited physiological properties consistent with mature neuronal function, the N398 neuronal population responded more actively with an increased excitatory postsynaptic current response upon the application of nicotine in both DA and glutamatergic neurons. Glutamatergic N398 neurons responded to lower nicotine doses (0.1 μM) with greater frequency and amplitude but they also exhibited rapid desensitization, consistent with previous analyses of N398-associated nicotinic receptor function. This study offers a proof-of-principle for utilizing human neurons to study gene variants contribution to addiction.
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Affiliation(s)
- Eileen N Oni
- Cell Biology and Neuroscience, Rutgers University, Piscataway, NJ, USA
| | - Apoorva Halikere
- Child Health Institute of New Jersey &Dept. of Neuroscience and Cell Biology, Rutgers Robert Wood Johnson Medical School, New Brunswick, NJ, USA
| | - Guohui Li
- Child Health Institute of New Jersey &Dept. of Neuroscience and Cell Biology, Rutgers Robert Wood Johnson Medical School, New Brunswick, NJ, USA
| | | | - Mavis R Swerdel
- Cell Biology and Neuroscience, Rutgers University, Piscataway, NJ, USA
| | - Jessica L Verpeut
- Department of Animal Sciences, Rutgers University, New Brunswick, NJ, USA
| | - Jennifer C Moore
- Human Genetics Institute of New Jersey, Rutgers University and RWJMS, Piscataway, NJ, USA.,Department of Human Genetics, Rutgers University, Piscataway, NJ, USA
| | - Nicholas T Bello
- Department of Animal Sciences, Rutgers University, New Brunswick, NJ, USA
| | - Laura J Bierut
- Department of Psychiatry, Washington University School of Medicine in St. Louis, St. Louis, MO, USA
| | - Alison Goate
- Neuroscience Department, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Jay A Tischfield
- Human Genetics Institute of New Jersey, Rutgers University and RWJMS, Piscataway, NJ, USA.,Department of Human Genetics, Rutgers University, Piscataway, NJ, USA
| | - Zhiping P Pang
- Child Health Institute of New Jersey &Dept. of Neuroscience and Cell Biology, Rutgers Robert Wood Johnson Medical School, New Brunswick, NJ, USA.,Human Genetics Institute of New Jersey, Rutgers University and RWJMS, Piscataway, NJ, USA
| | - Ronald P Hart
- Cell Biology and Neuroscience, Rutgers University, Piscataway, NJ, USA.,Human Genetics Institute of New Jersey, Rutgers University and RWJMS, Piscataway, NJ, USA
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FoxO3 regulates neuronal reprogramming of cells from postnatal and aging mice. Proc Natl Acad Sci U S A 2016; 113:8514-9. [PMID: 27402759 DOI: 10.1073/pnas.1607079113] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
We and others have shown that embryonic and neonatal fibroblasts can be directly converted into induced neuronal (iN) cells with mature functional properties. Reprogramming of fibroblasts from adult and aged mice, however, has not yet been explored in detail. The ability to generate fully functional iN cells from aged organisms will be particularly important for in vitro modeling of diseases of old age. Here, we demonstrate production of functional iN cells from fibroblasts that were derived from mice close to the end of their lifespan. iN cells from aged mice had apparently normal active and passive neuronal membrane properties and formed abundant synaptic connections. The reprogramming efficiency gradually decreased with fibroblasts derived from embryonic and neonatal mice, but remained similar for fibroblasts from postnatal mice of all ages. Strikingly, overexpression of a transcription factor, forkhead box O3 (FoxO3), which is implicated in aging, blocked iN cell conversion of embryonic fibroblasts, whereas knockout or knockdown of FoxO3 increased the reprogramming efficiency of adult-derived but not of embryonic fibroblasts and also enhanced functional maturation of resulting iN cells. Hence, FoxO3 has a central role in the neuronal reprogramming susceptibility of cells, and the importance of FoxO3 appears to change during development.
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43
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Sclip A, Bacaj T, Giam LR, Südhof TC. Extended Synaptotagmin (ESyt) Triple Knock-Out Mice Are Viable and Fertile without Obvious Endoplasmic Reticulum Dysfunction. PLoS One 2016; 11:e0158295. [PMID: 27348751 PMCID: PMC4922586 DOI: 10.1371/journal.pone.0158295] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2016] [Accepted: 06/13/2016] [Indexed: 01/15/2023] Open
Abstract
Extended synaptotagmins (ESyts) are endoplasmic reticulum (ER) proteins composed of an N-terminal transmembrane region, a central SMP-domain, and five (ESyt1) or three C-terminal cytoplasmic C2-domains (ESyt2 and ESyt3). ESyts bind phospholipids in a Ca2+-dependent manner via their C2-domains, are localized to ER-plasma membrane contact sites, and may catalyze lipid exchange between the plasma membrane and the ER via their SMP-domains. However, the overall function of ESyts has remained enigmatic. Here, we generated triple constitutive and conditional knock-out mice that lack all three ESyt isoforms; in addition, we produced knock-in mice that express mutant ESyt1 or ESyt2 carrying inactivating substitutions in the Ca2+-binding sites of their C2A-domains. Strikingly, all ESyt mutant mice, even those lacking all ESyts, were apparently normal and survived and bred in a manner indistinguishable from control mice. ESyt mutant mice displayed no major changes in brain morphology or synaptic protein composition, and exhibited no large alterations in stress responses. Thus, in mice ESyts do not perform an essential role in basic cellular functions, suggesting that these highly conserved proteins may perform a specialized role that may manifest only during specific, as yet untested challenges.
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Affiliation(s)
- Alessandra Sclip
- Department of Molecular and Cellular Physiology, Stanford University School of Medicine, 265 Campus Drive, Stanford, CA, 94305–5453, United States of America
- Howard Hughes Medical Institute, Stanford University Medical School, 265 Campus Drive, Stanford, CA, United States of America
| | - Taulant Bacaj
- Department of Molecular and Cellular Physiology, Stanford University School of Medicine, 265 Campus Drive, Stanford, CA, 94305–5453, United States of America
| | - Louise R. Giam
- Department of Molecular and Cellular Physiology, Stanford University School of Medicine, 265 Campus Drive, Stanford, CA, 94305–5453, United States of America
| | - Thomas C. Südhof
- Department of Molecular and Cellular Physiology, Stanford University School of Medicine, 265 Campus Drive, Stanford, CA, 94305–5453, United States of America
- Howard Hughes Medical Institute, Stanford University Medical School, 265 Campus Drive, Stanford, CA, United States of America
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Held RG, Liu C, Kaeser PS. ELKS controls the pool of readily releasable vesicles at excitatory synapses through its N-terminal coiled-coil domains. eLife 2016; 5. [PMID: 27253063 PMCID: PMC4935463 DOI: 10.7554/elife.14862] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2016] [Accepted: 06/01/2016] [Indexed: 12/27/2022] Open
Abstract
In a presynaptic nerve terminal, synaptic strength is determined by the pool of readily releasable vesicles (RRP) and the probability of release (P) of each RRP vesicle. These parameters are controlled at the active zone and vary across synapses, but how such synapse specific control is achieved is not understood. ELKS proteins are enriched at vertebrate active zones and enhance P at inhibitory hippocampal synapses, but ELKS functions at excitatory synapses are not known. Studying conditional knockout mice for ELKS, we find that ELKS enhances the RRP at excitatory synapses without affecting P. Surprisingly, ELKS C-terminal sequences, which interact with RIM, are dispensable for RRP enhancement. Instead, the N-terminal ELKS coiled-coil domains that bind to Liprin-α and Bassoon are necessary to control RRP. Thus, ELKS removal has differential, synapse-specific effects on RRP and P, and our findings establish important roles for ELKS N-terminal domains in synaptic vesicle priming.
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Affiliation(s)
- Richard G Held
- Department of Neurobiology, Harvard Medical School, Boston, United States
| | - Changliang Liu
- Department of Neurobiology, Harvard Medical School, Boston, United States
| | - Pascal S Kaeser
- Department of Neurobiology, Harvard Medical School, Boston, United States
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45
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α/β-Hydrolase domain-containing 6 (ABHD6) negatively regulates the surface delivery and synaptic function of AMPA receptors. Proc Natl Acad Sci U S A 2016; 113:E2695-704. [PMID: 27114538 DOI: 10.1073/pnas.1524589113] [Citation(s) in RCA: 50] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
In the brain, AMPA-type glutamate receptors are major postsynaptic receptors at excitatory synapses that mediate fast neurotransmission and synaptic plasticity. α/β-Hydrolase domain-containing 6 (ABHD6), a monoacylglycerol lipase, was previously found to be a component of AMPA receptor macromolecular complexes, but its physiological significance in the function of AMPA receptors (AMPARs) has remained unclear. The present study shows that overexpression of ABHD6 in neurons drastically reduced excitatory neurotransmission mediated by AMPA but not by NMDA receptors at excitatory synapses. Inactivation of ABHD6 expression in neurons by either CRISPR/Cas9 or shRNA knockdown methods significantly increased excitatory neurotransmission at excitatory synapses. Interestingly, overexpression of ABHD6 reduced glutamate-induced currents and the surface expression of GluA1 in HEK293T cells expressing GluA1 and stargazin, suggesting a direct functional interaction between these two proteins. The C-terminal tail of GluA1 was required for the binding between of ABHD6 and GluA1. Mutagenesis analysis revealed a GFCLIPQ sequence in the GluA1 C terminus that was essential for the inhibitory effect of ABHD6. The hydrolase activity of ABHD6 was not required for the effects of ABHD6 on AMPAR function in either neurons or transfected HEK293T cells. Thus, these findings reveal a novel and unexpected mechanism governing AMPAR trafficking at synapses through ABHD6.
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46
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Yi F, Danko T, Botelho SC, Patzke C, Pak C, Wernig M, Südhof TC. Autism-associated SHANK3 haploinsufficiency causes Ih channelopathy in human neurons. Science 2016; 352:aaf2669. [PMID: 26966193 DOI: 10.1126/science.aaf2669] [Citation(s) in RCA: 213] [Impact Index Per Article: 26.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2016] [Accepted: 02/26/2016] [Indexed: 12/13/2022]
Abstract
Heterozygous SHANK3 mutations are associated with idiopathic autism and Phelan-McDermid syndrome. SHANK3 is a ubiquitously expressed scaffolding protein that is enriched in postsynaptic excitatory synapses. Here, we used engineered conditional mutations in human neurons and found that heterozygous and homozygous SHANK3 mutations severely and specifically impaired hyperpolarization-activated cation (Ih) channels. SHANK3 mutations caused alterations in neuronal morphology and synaptic connectivity; chronic pharmacological blockage of Ih channels reproduced these phenotypes, suggesting that they may be secondary to Ih-channel impairment. Moreover, mouse Shank3-deficient neurons also exhibited severe decreases in Ih currents. SHANK3 protein interacted with hyperpolarization-activated cyclic nucleotide-gated channel proteins (HCN proteins) that form Ih channels, indicating that SHANK3 functions to organize HCN channels. Our data suggest that SHANK3 mutations predispose to autism, at least partially, by inducing an Ih channelopathy that may be amenable to pharmacological intervention.
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Affiliation(s)
- Fei Yi
- Department of Molecular and Cellular Physiology, Stanford University School of Medicine, 265 Campus Drive, Stanford, CA 94305, USA
| | - Tamas Danko
- Department of Molecular and Cellular Physiology, Stanford University School of Medicine, 265 Campus Drive, Stanford, CA 94305, USA. Institute for Stem Cell Biology and Regenerative Medicine, Stanford University School of Medicine, 265 Campus Drive, Stanford, CA 94305, USA. Department of Pathology, Stanford University School of Medicine, 265 Campus Drive, Stanford, CA 94305, USA
| | - Salome Calado Botelho
- Department of Molecular and Cellular Physiology, Stanford University School of Medicine, 265 Campus Drive, Stanford, CA 94305, USA
| | - Christopher Patzke
- Department of Molecular and Cellular Physiology, Stanford University School of Medicine, 265 Campus Drive, Stanford, CA 94305, USA
| | - ChangHui Pak
- Department of Molecular and Cellular Physiology, Stanford University School of Medicine, 265 Campus Drive, Stanford, CA 94305, USA
| | - Marius Wernig
- Institute for Stem Cell Biology and Regenerative Medicine, Stanford University School of Medicine, 265 Campus Drive, Stanford, CA 94305, USA. Department of Pathology, Stanford University School of Medicine, 265 Campus Drive, Stanford, CA 94305, USA
| | - Thomas C Südhof
- Department of Molecular and Cellular Physiology, Stanford University School of Medicine, 265 Campus Drive, Stanford, CA 94305, USA. Howard Hughes Medical Institute, Stanford University School of Medicine, 265 Campus Drive, Stanford, CA 94305, USA.
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47
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Pathogenic mechanism of an autism-associated neuroligin mutation involves altered AMPA-receptor trafficking. Mol Psychiatry 2016; 21:169-77. [PMID: 25778475 PMCID: PMC4573762 DOI: 10.1038/mp.2015.20] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/16/2014] [Revised: 01/21/2015] [Accepted: 01/23/2015] [Indexed: 02/01/2023]
Abstract
Neuroligins are postsynaptic cell-adhesion molecules that bind to presynaptic neurexins. Although the general synaptic role of neuroligins is undisputed, their specific functions at a synapse remain unclear, even controversial. Moreover, many neuroligin gene mutations were associated with autism, but the pathophysiological relevance of these mutations is often unknown, and their mechanisms of action uninvestigated. Here, we examine the synaptic effects of an autism-associated neuroligin-4 substitution (called R704C), which mutates a cytoplasmic arginine residue that is conserved in all neuroligins. We show that the R704C mutation, when introduced into neuroligin-3, enhances the interaction between neuroligin-3 and AMPA receptors, increases AMPA-receptor internalization and decreases postsynaptic AMPA-receptor levels. When introduced into neuroligin-4, conversely, the R704C mutation unexpectedly elevated AMPA-receptor-mediated synaptic responses. These results suggest a general functional link between neuroligins and AMPA receptors, indicate that both neuroligin-3 and -4 act at excitatory synapses but perform surprisingly distinct functions, and demonstrate that the R704C mutation significantly impairs the normal function of neuroligin-4, thereby validating its pathogenicity.
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48
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Guo Y, Liu C, Hu L, Wang X, Alam M, Wang H. An economic method to build a puffing instrument for drug application in vitro. J Neurosci Methods 2015; 256:122-6. [PMID: 26343324 DOI: 10.1016/j.jneumeth.2015.08.032] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2015] [Revised: 08/22/2015] [Accepted: 08/26/2015] [Indexed: 11/29/2022]
Abstract
BACKGROUND In in vitro electrophysiological studies, a quick application of picoliters of drug within milliseconds is required to avoid the desensitization of membrane receptors. However, conventional gravity-fed drug delivery devices sometime fail to achieve this. Moreover, the high financial cost of the advanced drug delivery system often limits the application of commercial instruments in academic research. NEW METHOD Taking advantage of the availability of data acquisition system and software in almost every electrophysiology laboratory, a simple puffing device was designed and assembled using low-cost commercially off-the-shelf components to inject picoliter amounts of drugs. RESULTS An optimal drug delivery with precise timing and volume was achieved using the custom made puffing device. The glutamate-evoked currents of cortical neurons recorded with patch-clamp technique were maintained for a prolonged period of time. Similarly, puffed inhibitory transmitters including GABA and glycine also produced satisfactory currents. COMPARISON WITH EXISTING METHOD(S) Our custom-made puffing system holds the advantage over conventional gravity-fed systems in operating within milliseconds of time. The channel number of the new device can easily be increased by simply adding more identical modules in parallel, and thus offering more flexibility than commercial puffing devices. CONCLUSIONS This custom-made puffing device can be characterized as reliable, modular and inexpensive system for modern drug delivery research and application.
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Affiliation(s)
- Yiping Guo
- Key Laboratory of Regenerative Biology, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou 510530, Guangdong, China; Guangdong Provincial Key Laboratory of Stem Cell and Regenerative Medicine, Guangzhou 510530, Guangdong, China
| | - Chunhua Liu
- Key Laboratory of Regenerative Biology, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou 510530, Guangdong, China; Guangdong Provincial Key Laboratory of Stem Cell and Regenerative Medicine, Guangzhou 510530, Guangdong, China
| | - Lingli Hu
- Key Laboratory of Regenerative Biology, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou 510530, Guangdong, China; Guangdong Provincial Key Laboratory of Stem Cell and Regenerative Medicine, Guangzhou 510530, Guangdong, China
| | - Xiaoyun Wang
- Rehabilitation Institute, Guangdong Provincial Work Injury Rehabilitation Center, Guangzhou 510440, Guangdong, China
| | - Monzurul Alam
- Department of Integrative Biology and Physiology, University of California, Los Angeles, CA 90095, United States
| | - Haitao Wang
- Key Laboratory of Regenerative Biology, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou 510530, Guangdong, China; Guangdong Provincial Key Laboratory of Stem Cell and Regenerative Medicine, Guangzhou 510530, Guangdong, China.
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49
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Modeling Neurological Disease by Rapid Conversion of Human Urine Cells into Functional Neurons. Stem Cells Int 2015; 2016:2452985. [PMID: 26770203 PMCID: PMC4685145 DOI: 10.1155/2016/2452985] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2015] [Revised: 07/18/2015] [Accepted: 07/22/2015] [Indexed: 11/25/2022] Open
Abstract
Somatic cells can be directly converted into functional neurons by ectopic expression of defined factors and/or microRNAs. Since the first report of conversion mouse embryonic fibroblasts into functional neurons, the postnatal mouse, and human fibroblasts, astroglia, hepatocytes, and pericyte-derived cells have been converted into functional dopaminergic and motor neurons both in vitro and in vivo. However, it is invasive to get all these materials. In the current study, we provide a noninvasive approach to obtain directly reprogrammed functional neurons by overexpression of the transcription factors Ascl1, Brn2, NeuroD, c-Myc, and Myt1l in human urine cells. These induced neuronal (iN) cells could express multiple neuron-specific proteins and generate action potentials. Moreover, urine cells from Wilson's disease (WD) patient could also be directly converted into neurons. In conclusion, generation of iN cells from nonneural lineages is a feasible and befitting approach for neurological disease modeling.
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50
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Beske PH, Bradford AB, Grynovicki JO, Glotfelty EJ, Hoffman KM, Hubbard KS, Tuznik KM, McNutt PM. Botulinum and Tetanus Neurotoxin-Induced Blockade of Synaptic Transmission in Networked Cultures of Human and Rodent Neurons. Toxicol Sci 2015; 149:503-15. [PMID: 26615023 DOI: 10.1093/toxsci/kfv254] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Clinical manifestations of tetanus and botulism result from an intricate series of interactions between clostridial neurotoxins (CNTs) and nerve terminal proteins that ultimately cause proteolytic cleavage of SNARE (soluble N-ethylmaleimide-sensitive factor attachment protein receptor) proteins and functional blockade of neurotransmitter release. Although detection of cleaved SNARE proteins is routinely used as a molecular readout of CNT intoxication in cultured cells, impaired synaptic function is the pathophysiological basis of clinical disease. Work in our laboratory has suggested that the blockade of synaptic neurotransmission in networked neuron cultures offers a phenotypic readout of CNT intoxication that more closely replicates the functional endpoint of clinical disease. Here, we explore the value of measuring spontaneous neurotransmission frequencies as novel and functionally relevant readouts of CNT intoxication. The generalizability of this approach was confirmed in primary neuron cultures as well as human and mouse stem cell-derived neurons exposed to botulinum neurotoxin serotypes A-G and tetanus neurotoxin. The sensitivity and specificity of synaptic activity as a reporter of intoxication was evaluated in assays representing the principal clinical and research purposes of in vivo studies. Our findings confirm that synaptic activity offers a novel and functionally relevant readout for the in vitro characterizations of CNTs. They further suggest that the analysis of synaptic activity in neuronal cell cultures can serve as a surrogate for neuromuscular paralysis in the mouse lethal assay, and therefore is expected to significantly reduce the need for terminal animal use in toxin studies and facilitate identification of candidate therapeutics in cell-based screening assays.
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Affiliation(s)
- Phillip H Beske
- Cellular and Molecular Biology Branch, Research Division, United States Army Medical Research Institute of Chemical Defense, Aberdeen Proving Ground, Maryland
| | - Aaron B Bradford
- Cellular and Molecular Biology Branch, Research Division, United States Army Medical Research Institute of Chemical Defense, Aberdeen Proving Ground, Maryland
| | - Justin O Grynovicki
- Cellular and Molecular Biology Branch, Research Division, United States Army Medical Research Institute of Chemical Defense, Aberdeen Proving Ground, Maryland
| | - Elliot J Glotfelty
- Cellular and Molecular Biology Branch, Research Division, United States Army Medical Research Institute of Chemical Defense, Aberdeen Proving Ground, Maryland
| | - Katie M Hoffman
- Cellular and Molecular Biology Branch, Research Division, United States Army Medical Research Institute of Chemical Defense, Aberdeen Proving Ground, Maryland
| | - Kyle S Hubbard
- Cellular and Molecular Biology Branch, Research Division, United States Army Medical Research Institute of Chemical Defense, Aberdeen Proving Ground, Maryland
| | - Kaylie M Tuznik
- Cellular and Molecular Biology Branch, Research Division, United States Army Medical Research Institute of Chemical Defense, Aberdeen Proving Ground, Maryland
| | - Patrick M McNutt
- Cellular and Molecular Biology Branch, Research Division, United States Army Medical Research Institute of Chemical Defense, Aberdeen Proving Ground, Maryland
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