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Su M, Xuan E, Sun X, Pan G, Li D, Zheng H, Zhang YW, Li Y. Synaptic adhesion molecule protocadherin-γC5 mediates β-amyloid-induced neuronal hyperactivity and cognitive deficits in Alzheimer's disease. J Neurochem 2024; 168:1060-1079. [PMID: 38308496 DOI: 10.1111/jnc.16066] [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: 10/27/2023] [Revised: 01/16/2024] [Accepted: 01/18/2024] [Indexed: 02/04/2024]
Abstract
Neuronal hyperactivity induced by β-amyloid (Aβ) is an early pathological feature in Alzheimer's disease (AD) and contributes to cognitive decline in AD progression. However, the underlying mechanisms are still unclear. Here, we revealed that Aβ increased the expression level of synaptic adhesion molecule protocadherin-γC5 (Pcdh-γC5) in a Ca2+-dependent manner, associated with aberrant elevation of synapses in both Aβ-treated neurons in vitro and the cortex of APP/PS1 mice in vivo. By using Pcdhgc5 gene knockout mice, we demonstrated the critical function of Pcdh-γC5 in regulating neuronal synapse formation, synaptic transmission, and cognition. To further investigate the role of Pcdh-γC5 in AD pathogenesis, the aberrantly enhanced expression of Pcdh-γC5 in the brain of APP/PS1 mice was knocked down by shRNA. Downregulation of Pcdh-γC5 efficiently rescued neuronal hyperactivity and impaired cognition in APP/PS1 mice. Our findings revealed the pathophysiological role of Pcdh-γC5 in mediating Aβ-induced neuronal hyperactivity and cognitive deficits in AD and identified a novel mechanism underlying AD pathogenesis.
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Affiliation(s)
- Min Su
- Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, School of Medicine, Xiamen University, Xiamen, Fujian, China
| | - Erying Xuan
- Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, School of Medicine, Xiamen University, Xiamen, Fujian, China
| | - Xiangyi Sun
- Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, School of Medicine, Xiamen University, Xiamen, Fujian, China
| | - Gaojie Pan
- Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, School of Medicine, Xiamen University, Xiamen, Fujian, China
| | - Dandan Li
- Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, School of Medicine, Xiamen University, Xiamen, Fujian, China
| | - Honghua Zheng
- Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, School of Medicine, Xiamen University, Xiamen, Fujian, China
| | - Yun-Wu Zhang
- Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, School of Medicine, Xiamen University, Xiamen, Fujian, China
| | - Yanfang Li
- Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, School of Medicine, Xiamen University, Xiamen, Fujian, China
- Shenzhen Research Institute of Xiamen University, Shenzhen, Guangdong, China
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2
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Reiner A, Medina L, Abellan A, Deng Y, Toledo CA, Luksch H, Vega-Zuniga T, Riley NB, Hodos W, Karten HJ. Neurochemistry and circuit organization of the lateral spiriform nucleus of birds: A uniquely nonmammalian direct pathway component of the basal ganglia. J Comp Neurol 2024; 532:e25620. [PMID: 38733146 PMCID: PMC11090467 DOI: 10.1002/cne.25620] [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: 08/30/2023] [Revised: 03/24/2024] [Accepted: 04/16/2024] [Indexed: 05/13/2024]
Abstract
We used diverse methods to characterize the role of avian lateral spiriform nucleus (SpL) in basal ganglia motor function. Connectivity analysis showed that SpL receives input from globus pallidus (GP), and the intrapeduncular nucleus (INP) located ventromedial to GP, whose neurons express numerous striatal markers. SpL-projecting GP neurons were large and aspiny, while SpL-projecting INP neurons were medium sized and spiny. Connectivity analysis further showed that SpL receives inputs from subthalamic nucleus (STN) and substantia nigra pars reticulata (SNr), and that the SNr also receives inputs from GP, INP, and STN. Neurochemical analysis showed that SpL neurons express ENK, GAD, and a variety of pallidal neuron markers, and receive GABAergic terminals, some of which also contain DARPP32, consistent with GP pallidal and INP striatal inputs. Connectivity and neurochemical analysis showed that the SpL input to tectum prominently ends on GABAA receptor-enriched tectobulbar neurons. Behavioral studies showed that lesions of SpL impair visuomotor behaviors involving tracking and pecking moving targets. Our results suggest that SpL modulates brainstem-projecting tectobulbar neurons in a manner comparable to the demonstrated influence of GP internus on motor thalamus and of SNr on tectobulbar neurons in mammals. Given published data in amphibians and reptiles, it seems likely the SpL circuit represents a major direct pathway-type circuit by which the basal ganglia exerts its motor influence in nonmammalian tetrapods. The present studies also show that avian striatum is divided into three spatially segregated territories with differing connectivity, a medial striato-nigral territory, a dorsolateral striato-GP territory, and the ventrolateral INP motor territory.
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Affiliation(s)
- Anton Reiner
- Department of Anatomy and Neurobiology, The University of Tennessee Health Science Center, Memphis, TN 38163
| | - Loreta Medina
- Department of Experimental Medicine, Universitat de Lleida, Lleida, Spain
- Laboratory of Evolutionary and Developmental Neurobiology, Lleida’s Institute for Biomedical Research-Dr. Pifarré Foundation (IRBLleida), Lleida, Catalonia, Spain
| | - Antonio Abellan
- Department of Experimental Medicine, Universitat de Lleida, Lleida, Spain
- Laboratory of Evolutionary and Developmental Neurobiology, Lleida’s Institute for Biomedical Research-Dr. Pifarré Foundation (IRBLleida), Lleida, Catalonia, Spain
| | - Yunping Deng
- Department of Anatomy and Neurobiology, The University of Tennessee Health Science Center, Memphis, TN 38163
| | - Claudio A.B. Toledo
- Neuroscience Research Nucleus, Universidade Cidade de Sao Paulo, Sao Paulo 65057-420, Brazil
| | - Harald Luksch
- School of Life Sciences, Technische Universität München, Freising-Weihenstephan, Germany
| | - Tomas Vega-Zuniga
- School of Life Sciences, Technische Universität München, Freising-Weihenstephan, Germany
- Institute of Science and Technology Austria, Klosterneuburg, Austria
| | - Nell B. Riley
- Department of Psychology, University of Maryland College Park 20742-4411
| | - William Hodos
- Department of Psychology, University of Maryland College Park 20742-4411
| | - Harvey J. Karten
- Department of Neurosciences, University of California San Diego, San Diego, CA 92093-0608
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3
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Meltzer S, Boulanger KC, Chirila AM, Osei-Asante E, DeLisle M, Zhang Q, Kalish BT, Tasnim A, Huey EL, Fuller LC, Flaherty EK, Maniatis T, Garrett AM, Weiner JA, Ginty DD. γ-Protocadherins control synapse formation and peripheral branching of touch sensory neurons. Neuron 2023; 111:1776-1794.e10. [PMID: 37028432 PMCID: PMC10365546 DOI: 10.1016/j.neuron.2023.03.012] [Citation(s) in RCA: 14] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2022] [Revised: 01/20/2023] [Accepted: 03/07/2023] [Indexed: 04/09/2023]
Abstract
Light touch sensation begins with activation of low-threshold mechanoreceptor (LTMR) endings in the skin and propagation of their signals to the spinal cord and brainstem. We found that the clustered protocadherin gamma (Pcdhg) gene locus, which encodes 22 cell-surface homophilic binding proteins, is required in somatosensory neurons for normal behavioral reactivity to a range of tactile stimuli. Developmentally, distinct Pcdhg isoforms mediate LTMR synapse formation through neuron-neuron interactions and peripheral axonal branching through neuron-glia interactions. The Pcdhgc3 isoform mediates homophilic interactions between sensory axons and spinal cord neurons to promote synapse formation in vivo and is sufficient to induce postsynaptic specializations in vitro. Moreover, loss of Pcdhgs and somatosensory synaptic inputs to the dorsal horn leads to fewer corticospinal synapses on dorsal horn neurons. These findings reveal essential roles for Pcdhg isoform diversity in somatosensory neuron synapse formation, peripheral axonal branching, and stepwise assembly of central mechanosensory circuitry.
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Affiliation(s)
- Shan Meltzer
- Department of Neurobiology, Howard Hughes Medical Institute, Harvard Medical School, 220 Longwood Avenue, Boston, MA 02115, USA
| | - Katelyn C Boulanger
- Department of Neurobiology, Howard Hughes Medical Institute, Harvard Medical School, 220 Longwood Avenue, Boston, MA 02115, USA
| | - Anda M Chirila
- Department of Neurobiology, Howard Hughes Medical Institute, Harvard Medical School, 220 Longwood Avenue, Boston, MA 02115, USA
| | - Emmanuella Osei-Asante
- Department of Neurobiology, Howard Hughes Medical Institute, Harvard Medical School, 220 Longwood Avenue, Boston, MA 02115, USA
| | - Michelle DeLisle
- Department of Neurobiology, Howard Hughes Medical Institute, Harvard Medical School, 220 Longwood Avenue, Boston, MA 02115, USA
| | - Qiyu Zhang
- Department of Neurobiology, Howard Hughes Medical Institute, Harvard Medical School, 220 Longwood Avenue, Boston, MA 02115, USA
| | - Brian T Kalish
- Department of Neurobiology, Harvard Medical School, 220 Longwood Avenue, Boston, MA 02115, USA
| | - Aniqa Tasnim
- Department of Neurobiology, Howard Hughes Medical Institute, Harvard Medical School, 220 Longwood Avenue, Boston, MA 02115, USA
| | - Erica L Huey
- Department of Neurobiology, Howard Hughes Medical Institute, Harvard Medical School, 220 Longwood Avenue, Boston, MA 02115, USA
| | - Leah C Fuller
- Department of Biology and Iowa Neuroscience Institute, University of Iowa, 143 Biology Building, Iowa City, IA 52242, USA
| | - Erin K Flaherty
- Department of Biochemistry and Molecular Biophysics, Zuckerman Institute of Mind Brain and Behavior, Columbia University, New York, NY 10032, USA
| | - Tom Maniatis
- Department of Biochemistry and Molecular Biophysics, Zuckerman Institute of Mind Brain and Behavior, Columbia University, New York, NY 10032, USA
| | - Andrew M Garrett
- Department of Pharmacology and Department of Ophthalmology, Visual and Anatomical Sciences, Wayne State University School of Medicine, 540 E. Canfield St. 7322 Scott Hall, Detroit, MI 48201, USA
| | - Joshua A Weiner
- Department of Biology and Iowa Neuroscience Institute, University of Iowa, 143 Biology Building, Iowa City, IA 52242, USA
| | - David D Ginty
- Department of Neurobiology, Howard Hughes Medical Institute, Harvard Medical School, 220 Longwood Avenue, Boston, MA 02115, USA.
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4
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Nozawa O, Miyata M, Shiotani H, Kameyama T, Komaki R, Shimizu T, Kuriu T, Kashiwagi Y, Sato Y, Koebisu M, Aiba A, Okabe S, Mizutani K, Takai Y. Necl2/3-mediated mechanism for tripartite synapse formation. Development 2023; 150:285820. [PMID: 36458527 DOI: 10.1242/dev.200931] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2022] [Accepted: 11/23/2022] [Indexed: 12/05/2022]
Abstract
Ramified, polarized protoplasmic astrocytes interact with synapses via perisynaptic astrocyte processes (PAPs) to form tripartite synapses. These astrocyte-synapse interactions mutually regulate their structures and functions. However, molecular mechanisms for tripartite synapse formation remain elusive. We developed an in vitro co-culture system for mouse astrocytes and neurons that induced astrocyte ramifications and PAP formation. Co-cultured neurons were required for astrocyte ramifications in a neuronal activity-dependent manner, and synaptically-released glutamate and activation of astrocytic mGluR5 metabotropic glutamate receptor were likely involved in astrocyte ramifications. Astrocytic Necl2 trans-interacted with axonal Necl3, inducing astrocyte-synapse interactions and astrocyte functional polarization by recruiting EAAT1/2 glutamate transporters and Kir4.1 K+ channel to the PAPs, without affecting astrocyte ramifications. This Necl2/3 trans-interaction increased functional synapse number. Thus, astrocytic Necl2, synaptically-released glutamate and axonal Necl3 cooperatively formed tripartite glutamatergic synapses in vitro. Studies on hippocampal mossy fiber synapses in Necl3 knockout and Necl2/3 double knockout mice confirmed these previously unreported mechanisms for astrocyte-synapse interactions and astrocyte functional polarization in vivo.
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Affiliation(s)
- Osamu Nozawa
- Division of Pathogenetic Signaling, Department of Physiology and Cell Biology, Kobe University Graduate School of Medicine, Kobe, Hyogo 650-0047, Japan
| | - Muneaki Miyata
- Division of Pathogenetic Signaling, Department of Physiology and Cell Biology, Kobe University Graduate School of Medicine, Kobe, Hyogo 650-0047, Japan
| | - Hajime Shiotani
- Division of Pathogenetic Signaling, Department of Physiology and Cell Biology, Kobe University Graduate School of Medicine, Kobe, Hyogo 650-0047, Japan
| | - Takeshi Kameyama
- Division of Pathogenetic Signaling, Department of Physiology and Cell Biology, Kobe University Graduate School of Medicine, Kobe, Hyogo 650-0047, Japan
| | - Ryouhei Komaki
- Division of Pathogenetic Signaling, Department of Physiology and Cell Biology, Kobe University Graduate School of Medicine, Kobe, Hyogo 650-0047, Japan
| | - Tatsuhiro Shimizu
- Division of Pathogenetic Signaling, Department of Physiology and Cell Biology, Kobe University Graduate School of Medicine, Kobe, Hyogo 650-0047, Japan
| | - Toshihiko Kuriu
- Osaka Medical and Pharmaceutical University, Research and Development Center, Takatsuki, Osaka 569-8686, Japan
| | - Yutaro Kashiwagi
- Department of Cellular Neurobiology, Graduate School of Medicine, The University of Tokyo, Tokyo 113-0033, Japan
| | - Yuka Sato
- Department of Cellular Neurobiology, Graduate School of Medicine, The University of Tokyo, Tokyo 113-0033, Japan
| | - Michinori Koebisu
- Section of Animal Research and Laboratory of Animal Resources, Center for Disease Biology and Integrative Medicine, Graduate School of Medicine, The University of Tokyo, Tokyo 113-0033, Japan
| | - Atsu Aiba
- Section of Animal Research and Laboratory of Animal Resources, Center for Disease Biology and Integrative Medicine, Graduate School of Medicine, The University of Tokyo, Tokyo 113-0033, Japan
| | - Shigeo Okabe
- Department of Cellular Neurobiology, Graduate School of Medicine, The University of Tokyo, Tokyo 113-0033, Japan
| | - Kiyohito Mizutani
- Division of Pathogenetic Signaling, Department of Physiology and Cell Biology, Kobe University Graduate School of Medicine, Kobe, Hyogo 650-0047, Japan
| | - Yoshimi Takai
- Division of Pathogenetic Signaling, Department of Physiology and Cell Biology, Kobe University Graduate School of Medicine, Kobe, Hyogo 650-0047, Japan
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5
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Leon WRM, Steffen DM, Dale-Huang F, Rakela B, Breevoort A, Romero-Rodriguez R, Hasenstaub AR, Stryker MP, Weiner JA, Alvarez-Buylla A. The Clustered Gamma Protocadherin Pcdhγc4 Isoform Regulates Cortical Interneuron Programmed Cell Death in the Mouse Cortex. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.02.03.526887. [PMID: 36778455 PMCID: PMC9915683 DOI: 10.1101/2023.02.03.526887] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
Cortical function critically depends on inhibitory/excitatory balance. Cortical inhibitory interneurons (cINs) are born in the ventral forebrain and migrate into cortex, where their numbers are adjusted by programmed cell death. Previously, we showed that loss of clustered gamma protocadherins (Pcdhγ), but not of genes in the alpha or beta clusters, increased dramatically cIN BAX-dependent cell death in mice. Here we show that the sole deletion of the Pcdhγc4 isoform, but not of the other 21 isoforms in the Pcdhγ gene cluster, increased cIN cell death in mice during the normal period of programmed cell death. Viral expression of the Pcdhγc4 isoform rescued transplanted cINs lacking Pcdhγ from cell death. We conclude that Pcdhγ, specifically Pcdhγc4, plays a critical role in regulating the survival of cINs during their normal period of cell death. This demonstrates a novel specificity in the role of Pcdhγ isoforms in cortical development.
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Affiliation(s)
- Walter R Mancia Leon
- Department of Neurological Surgery and The Eli and Edythe Broad Center of Regeneration Medicine and Stem Cell Research, University of California, San Francisco, San Francisco, United States
| | - David M Steffen
- Department of Neurological Surgery and The Eli and Edythe Broad Center of Regeneration Medicine and Stem Cell Research, University of California, San Francisco, San Francisco, United States
- Iowa Neuroscience Institute, The University of Iowa, Iowa City, IA 52242
- Department of Biology, The University of Iowa, Iowa City IA 52242
| | - Fiona Dale-Huang
- Department of Neurological Surgery and The Eli and Edythe Broad Center of Regeneration Medicine and Stem Cell Research, University of California, San Francisco, San Francisco, United States
| | - Benjamin Rakela
- Department of Physiology and Center for Integrative Neuroscience, University of California, San Francisco, San Francisco, United States
| | - Arnar Breevoort
- Department of Physiology and Center for Integrative Neuroscience, University of California, San Francisco, San Francisco, United States
| | - Ricardo Romero-Rodriguez
- Department of Neurological Surgery and The Eli and Edythe Broad Center of Regeneration Medicine and Stem Cell Research, University of California, San Francisco, San Francisco, United States
| | - Andrea R Hasenstaub
- Department of Otolaryngology-Head and Neck Surgery, University of California, San Francisco, San Francisco, United States
- Kavli Institute for Fundamental Neuroscience, University of California, San Francisco, San Francisco, United States
| | - Michael P Stryker
- Department of Physiology and Center for Integrative Neuroscience, University of California, San Francisco, San Francisco, United States
- Kavli Institute for Fundamental Neuroscience, University of California, San Francisco, San Francisco, United States
| | - Joshua A Weiner
- Iowa Neuroscience Institute, The University of Iowa, Iowa City, IA 52242
- Department of Biology, The University of Iowa, Iowa City IA 52242
| | - Arturo Alvarez-Buylla
- Department of Neurological Surgery and The Eli and Edythe Broad Center of Regeneration Medicine and Stem Cell Research, University of California, San Francisco, San Francisco, United States
- Kavli Institute for Fundamental Neuroscience, University of California, San Francisco, San Francisco, United States
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6
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Neuronal and astrocytic protein connections and associated adhesion molecules. Neurosci Res 2023; 187:14-20. [PMID: 36202350 DOI: 10.1016/j.neures.2022.09.014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2022] [Revised: 08/12/2022] [Accepted: 09/27/2022] [Indexed: 02/11/2023]
Abstract
Astrocytes are morphologically complex, with a myriad of processes which allow contact with other astrocytes, blood vessels, and neurons. Adhesion molecules expressed by these cells regulate this connectivity. Adhesion molecules are required to form and maintain functional neural circuits, but their importance and mechanisms of action, particularly in astrocyte-neuron contact, remain unresolved. Several studies of neuron-astrocyte connections have demonstrated the vital functions of adhesion molecules, including neuron-glia cell adhesion molecules, astrotactins, and protocadherins. In this review, we provide an overview and perspective of astrocyte-neuron contacts mediated by adhesion molecules in developing neural circuits and synapse formation, especially in the cerebellum. We also outline a novel mechanism of interaction between neurons and astrocytes in the tripartite synapses that has been recently found by our group.
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7
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Bassi JK, Connelly AA, Butler AG, Liu Y, Ghanbari A, Farmer DGS, Jenkins MW, Melo MR, McDougall SJ, Allen AM. Analysis of the distribution of vagal afferent projections from different peripheral organs to the nucleus of the solitary tract in rats. J Comp Neurol 2022; 530:3072-3103. [PMID: 35988033 PMCID: PMC9804483 DOI: 10.1002/cne.25398] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2022] [Revised: 07/26/2022] [Accepted: 08/02/2022] [Indexed: 01/05/2023]
Abstract
Anatomical tracing studies examining the vagal system can conflate details of sensory afferent and motor efferent neurons. Here, we used a serotype of adeno-associated virus that transports retrogradely and exhibits selective tropism for vagal afferents, to map their soma location and central termination sites within the nucleus of the solitary tract (NTS). We examined the vagal sensory afferents innervating the trachea, duodenum, stomach, or heart, and in some animals, from two organs concurrently. We observed no obvious somatotopy in the somata distribution within the nodose ganglion. The central termination patterns of afferents from different organs within the NTS overlap substantially. Convergence of vagal afferent inputs from different organs onto single NTS neurons is observed. Abdominal and thoracic afferents terminate throughout the NTS, including in the rostral NTS, where the 7th cranial nerve inputs are known to synapse. To address whether the axonal labeling produced by viral transduction is so widespread because it fills axons traveling to their targets, and not just terminal fields, we labeled pre and postsynaptic elements of vagal afferents in the NTS . Vagal afferents form multiple putative synapses as they course through the NTS, with each vagal afferent neuron distributing sensory signals to multiple second-order NTS neurons. We observe little selectivity between vagal afferents from different visceral targets and NTS neurons with common neurochemical phenotypes, with afferents from different organs making close appositions with the same NTS neuron. We conclude that specific viscerosensory information is distributed widely within the NTS and that the coding of this input is probably determined by the intrinsic properties and projections of the second-order neuron.
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Affiliation(s)
- Jaspreet K. Bassi
- Department of Anatomy and PhysiologyThe University of MelbourneParkvilleVictoriaAustralia
| | - Angela A. Connelly
- Department of Anatomy and PhysiologyThe University of MelbourneParkvilleVictoriaAustralia
| | - Andrew G. Butler
- Department of Anatomy and PhysiologyThe University of MelbourneParkvilleVictoriaAustralia
| | - Yehe Liu
- Department of Biomedical EngineeringCase Western Reserve UniversityClevelandOhioUSA
| | - Anahita Ghanbari
- Department of Anatomy and PhysiologyThe University of MelbourneParkvilleVictoriaAustralia,Department of Queensland Brain InstituteThe University of QueenslandSt LuciaQueenslandAustralia
| | - David G. S. Farmer
- Department of Anatomy and PhysiologyThe University of MelbourneParkvilleVictoriaAustralia
| | - Michael W. Jenkins
- Department of Biomedical EngineeringCase Western Reserve UniversityClevelandOhioUSA
| | - Mariana R. Melo
- Department of Anatomy and PhysiologyThe University of MelbourneParkvilleVictoriaAustralia
| | - Stuart J. McDougall
- Department of Florey Institute of Neuroscience and Mental HealthThe University of MelbourneParkvilleVictoriaAustralia
| | - Andrew M. Allen
- Department of Anatomy and PhysiologyThe University of MelbourneParkvilleVictoriaAustralia,Department of Florey Institute of Neuroscience and Mental HealthThe University of MelbourneParkvilleVictoriaAustralia
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8
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Selective Overexpression of Collybistin in Mouse Hippocampal Pyramidal Cells Enhances GABAergic Neurotransmission and Protects against PTZ-Induced Seizures. eNeuro 2021; 8:ENEURO.0561-20.2021. [PMID: 34083383 PMCID: PMC8281261 DOI: 10.1523/eneuro.0561-20.2021] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2020] [Revised: 04/02/2021] [Accepted: 05/23/2021] [Indexed: 11/21/2022] Open
Abstract
Collybistin (CB) is a rho guanine exchange factor found at GABAergic and glycinergic postsynapses that interacts with the inhibitory scaffold protein, gephyrin, and induces accumulation of gephyrin and GABA type-A receptors (GABAARs) to the postsynapse. We have previously reported that the isoform without the src homology 3 (SH3) domain, CBSH3-, is particularly active in enhancing the GABAergic postsynapse in both cultured hippocampal neurons as well as in cortical pyramidal neurons after chronic in vivo expression in in utero electroporated (IUE) rats. Deficiency of CB in knock-out (KO) mice results in absence of gephyrin and gephyrin-dependent GABAARs at postsynaptic sites in several brain regions, including hippocampus. In the present study, we have generated an adeno-associated virus (AAV) that expresses CBSH3- in a cre-dependent manner. Using male and female VGLUT1-IRES-cre or VGAT-IRES-cre mice, we explore the effect of overexpression of CBSH3- in hippocampal pyramidal cells or hippocampal interneurons. The results show that: (1) the accumulation of gephyrin and GABAARs at inhibitory postsynapses in hippocampal pyramidal neurons or interneurons can be enhanced by CBSH3- overexpression; (2) overexpression of CBSH3- in hippocampal pyramidal cells can enhance the strength of inhibitory neurotransmission; and (3) these enhanced inhibitory synapses provide protection against pentylenetetrazole (PTZ)-induced seizures. The results indicate that this AAV vector carrying CBSH3- can be used for in vivo enhancement of GABAergic synaptic transmission in selected target neurons in the brain.
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9
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George S, Chiou TT, Kanamalla K, De Blas AL. Recruitment of Plasma Membrane GABA-A Receptors by Submembranous Gephyrin/Collybistin Clusters. Cell Mol Neurobiol 2021; 42:1585-1604. [PMID: 33547626 DOI: 10.1007/s10571-021-01050-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2020] [Accepted: 01/23/2021] [Indexed: 11/29/2022]
Abstract
It has been shown that subunit composition is the main determinant of the synaptic or extrasynaptic localization of GABAA receptors (GABAARs). Synaptic and extrasynaptic GABAARs are involved in phasic and tonic inhibition, respectively. It has been proposed that synaptic GABAARs bind to the postsynaptic gephyrin/collybistin (Geph/CB) lattice, but not the typically extrasynaptic GABAARs. Nevertheless, there are no studies of the direct binding of various types of GABAARs with the submembranous Geph/CB lattice in the absence of other synaptic proteins, some of which are known to interact with GABAARs. We have reconstituted GABAARs of various subunit compositions, together with the Geph/CB scaffold, in HEK293 cells, and have investigated the recruitment of surface GABAARs by submembranous Geph/CB clusters. Results show that the typically synaptic α1β3γ2 GABAARs were trapped by submembranous Geph/CB clusters. The α5β3γ2 GABAARs, which are both synaptic and extrasynaptic, were also trapped by Geph/CB clusters. Extrasynaptic α4β3δ GABAARs consistently showed little or no trapping by the Geph/CB clusters. However, the extrasynaptic α6β3δ, α1β3, α6β3 (and less α4β3) GABAARs were highly trapped by the Geph/CB clusters. AMPA and NMDA glutamate receptors were not trapped. The results suggest: (I) in the absence of other synaptic molecules, the Geph/CB lattice has the capacity to trap not only synaptic but also several typically extrasynaptic GABAARs; (II) the Geph/CB lattice is important but does not play a decisive role in the synaptic localization of GABAARs; and (III) in neurons there must be mechanisms preventing the trapping of several typically extrasynaptic GABAARs by the postsynaptic Geph/CB lattice.
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Affiliation(s)
- Shanu George
- Department of Physiology and Neurobiology, University of Connecticut, 75 North Eagleville Road, U-3156, Storrs, CT, 06269-3156, USA
| | - Tzu-Ting Chiou
- Department of Physiology and Neurobiology, University of Connecticut, 75 North Eagleville Road, U-3156, Storrs, CT, 06269-3156, USA
| | - Karthik Kanamalla
- Department of Physiology and Neurobiology, University of Connecticut, 75 North Eagleville Road, U-3156, Storrs, CT, 06269-3156, USA
| | - Angel L De Blas
- Department of Physiology and Neurobiology, University of Connecticut, 75 North Eagleville Road, U-3156, Storrs, CT, 06269-3156, USA.
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10
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George S, Bear J, Taylor MJ, Kanamalla K, Fekete CD, Chiou TT, Miralles CP, Papadopoulos T, De Blas AL. Collybistin SH3-protein isoforms are expressed in the rat brain promoting gephyrin and GABA-A receptor clustering at GABAergic synapses. J Neurochem 2021; 157:1032-1051. [PMID: 33316079 DOI: 10.1111/jnc.15270] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2020] [Revised: 11/18/2020] [Accepted: 12/08/2020] [Indexed: 01/21/2023]
Abstract
Collybistin (CB) is a guanine nucleotide exchange factor (GEF) selectively localized at GABAergic and glycinergic postsynapses. Analysis of mRNA shows that several isoforms of collybistin are expressed in the brain. Some of the isoforms have a SH3 domain (CBSH3+) and some have no SH3 domain (CBSH3-). The CBSH3+ mRNAs are predominantly expressed over CBSH3-. However, in an immunoblot study of mouse brain homogenates, only CBSH3+ protein isoforms were detected, proposing that CBSH3- protein might not be expressed in the brain. The expression or lack of expression of CBSH3- protein is an important issue because CBSH3- has a strong effect in promoting the postsynaptic clustering of gephyrin and GABA-A receptors (GABAA Rs). Moreover CBSH3- is constitutively active; therefore lower expression of CBSH3- protein might play a relatively stronger functional role than the more abundant but self-inhibited CBSH3+ isoforms, which need to be activated. We are now showing that: (a) CBSH3- protein is expressed in the brain; (b) parvalbumin positive (PV+) interneurons show higher expression of CBSH3- protein than other neurons; (c) CBSH3- is associated with GABAergic synapses in various regions of the brain and (d) knocking down CBSH3- in hippocampal neurons decreases the synaptic clustering of gephyrin and GABAA Rs. The results show that CBSH3- protein is expressed in the brain and that it plays a significant role in the size regulation of the GABAergic postsynapse.
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Affiliation(s)
- Shanu George
- Department of Physiology and Neurobiology, University of Connecticut, Storrs, CT, USA
| | - John Bear
- Department of Physiology and Neurobiology, University of Connecticut, Storrs, CT, USA
| | - Michael J Taylor
- Department of Physiology and Neurobiology, University of Connecticut, Storrs, CT, USA
| | - Karthik Kanamalla
- Department of Physiology and Neurobiology, University of Connecticut, Storrs, CT, USA
| | - Christopher D Fekete
- Department of Physiology and Neurobiology, University of Connecticut, Storrs, CT, USA
| | - Tzu-Ting Chiou
- Department of Physiology and Neurobiology, University of Connecticut, Storrs, CT, USA
| | - Celia P Miralles
- Department of Physiology and Neurobiology, University of Connecticut, Storrs, CT, USA
| | | | - Angel L De Blas
- Department of Physiology and Neurobiology, University of Connecticut, Storrs, CT, USA
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11
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Right Place at the Right Time: How Changes in Protocadherins Affect Synaptic Connections Contributing to the Etiology of Neurodevelopmental Disorders. Cells 2020; 9:cells9122711. [PMID: 33352832 PMCID: PMC7766791 DOI: 10.3390/cells9122711] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2020] [Revised: 12/14/2020] [Accepted: 12/15/2020] [Indexed: 11/17/2022] Open
Abstract
During brain development, neurons need to form the correct connections with one another in order to give rise to a functional neuronal circuitry. Mistakes during this process, leading to the formation of improper neuronal connectivity, can result in a number of brain abnormalities and impairments collectively referred to as neurodevelopmental disorders. Cell adhesion molecules (CAMs), present on the cell surface, take part in the neurodevelopmental process regulating migration and recognition of specific cells to form functional neuronal assemblies. Among CAMs, the members of the protocadherin (PCDH) group stand out because they are involved in cell adhesion, neurite initiation and outgrowth, axon pathfinding and fasciculation, and synapse formation and stabilization. Given the critical role of these macromolecules in the major neurodevelopmental processes, it is not surprising that clinical and basic research in the past two decades has identified several PCDH genes as responsible for a large fraction of neurodevelopmental disorders. In the present article, we review these findings with a focus on the non-clustered PCDH sub-group, discussing the proteins implicated in the main neurodevelopmental disorders.
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12
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Pancho A, Aerts T, Mitsogiannis MD, Seuntjens E. Protocadherins at the Crossroad of Signaling Pathways. Front Mol Neurosci 2020; 13:117. [PMID: 32694982 PMCID: PMC7339444 DOI: 10.3389/fnmol.2020.00117] [Citation(s) in RCA: 69] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2020] [Accepted: 06/08/2020] [Indexed: 12/25/2022] Open
Abstract
Protocadherins (Pcdhs) are cell adhesion molecules that belong to the cadherin superfamily, and are subdivided into clustered (cPcdhs) and non-clustered Pcdhs (ncPcdhs) in vertebrates. In this review, we summarize their discovery, expression mechanisms, and roles in neuronal development and cancer, thereby highlighting the context-dependent nature of their actions. We furthermore provide an extensive overview of current structural knowledge, and its implications concerning extracellular interactions between cPcdhs, ncPcdhs, and classical cadherins. Next, we survey the known molecular action mechanisms of Pcdhs, emphasizing the regulatory functions of proteolytic processing and domain shedding. In addition, we outline the importance of Pcdh intracellular domains in the regulation of downstream signaling cascades, and we describe putative Pcdh interactions with intracellular molecules including components of the WAVE complex, the Wnt pathway, and apoptotic cascades. Our overview combines molecular interaction data from different contexts, such as neural development and cancer. This comprehensive approach reveals potential common Pcdh signaling hubs, and points out future directions for research. Functional studies of such key factors within the context of neural development might yield innovative insights into the molecular etiology of Pcdh-related neurodevelopmental disorders.
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Affiliation(s)
- Anna Pancho
- Laboratory of Developmental Neurobiology, Department of Biology, KU Leuven, Leuven, Belgium
| | - Tania Aerts
- Laboratory of Developmental Neurobiology, Department of Biology, KU Leuven, Leuven, Belgium
| | - Manuela D Mitsogiannis
- Laboratory of Developmental Neurobiology, Department of Biology, KU Leuven, Leuven, Belgium
| | - Eve Seuntjens
- Laboratory of Developmental Neurobiology, Department of Biology, KU Leuven, Leuven, Belgium
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13
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Chromatin establishes an immature version of neuronal protocadherin selection during the naive-to-primed conversion of pluripotent stem cells. Nat Genet 2019; 51:1691-1701. [PMID: 31740836 PMCID: PMC7061033 DOI: 10.1038/s41588-019-0526-4] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2019] [Accepted: 09/30/2019] [Indexed: 01/09/2023]
Abstract
In the mammalian genome, the clustered protocadherin (cPcdh) locus is a paradigm of stochastic gene expression with the potential to generate a unique cPcdh combination in every neuron. Here, we report a chromatin-based mechanism emerging during the transition from the naive to the primed states of cell pluripotency that reduces by orders of magnitude the combinatorial potential in the human cPcdh locus. This mechanism selectively increases the frequency of stochastic selection of a small subset of cPcdh genes after neuronal differentiation in monolayers, months-old organoids, and engrafted cells in the rat spinal cord. Signs of these frequent selections can be observed in the brain throughout fetal development and disappear after birth, unless there is a condition of delayed maturation such as Down Syndrome. We therefore propose that a pattern of limited cPcdh diversity is maintained while human neurons still retain fetal-like levels of maturation. Short and long-term cultures of human stem cell-derived neurons reveal that a pattern of restricted selection of clustered protocadherin isoforms, pre-established in pluripotent cells, distinguishes immature from mature neurons.
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14
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Miralles CP, Taylor MJ, Bear J, Fekete CD, George S, Li Y, Bonhomme B, Chiou TT, De Blas AL. Expression of protocadherin-γC4 protein in the rat brain. J Comp Neurol 2019; 528:840-864. [PMID: 31609469 DOI: 10.1002/cne.24783] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2019] [Revised: 09/24/2019] [Accepted: 09/30/2019] [Indexed: 12/26/2022]
Abstract
It has been proposed that the combinatorial expression of γ-protocadherins (Pcdh-γs) and other clustered protocadherins (Pcdhs) provides a code of molecular identity and individuality to neurons, which plays a major role in the establishment of specific synaptic connectivity and formation of neuronal circuits. Particular attention has been directed to the Pcdh-γ family, for which experimental evidence derived from Pcdh-γ-deficient mice shows that they are involved in dendrite self-avoidance, synapse development, dendritic arborization, spine maturation, and prevention of apoptosis of some neurons. Moreover, a triple-mutant mouse deficient in the three C-type members of the Pcdh-γ family (Pcdh-γC3, Pcdh-γC4, and Pcdh-γC5) shows a phenotype similar to the mouse deficient in whole Pcdh-γ family, indicating that the latter is largely due to the absence of C-type Pcdh-γs. The role of each individual C-type Pcdh-γ is not known. We have developed a specific antibody to Pcdh-γC4 to reveal the expression of this protein in the rat brain. The results show that although Pcdh-γC4 is expressed at higher levels in the embryo and earlier postnatal weeks, it is also expressed in the adult rat brain. Pcdh-γC4 is expressed in both neurons and astrocytes. In the adult brain, the regional distribution of Pcdh-γC4 immunoreactivity is similar to that of Pcdh-γC4 mRNA, being highest in the olfactory bulb, dentate gyrus, and cerebellum. Pcdh-γC4 forms puncta that are frequently apposed to glutamatergic and GABAergic synapses. They are also frequently associated with neuron-astrocyte contacts. The results provide new insights into the cell recognition function of Pcdh-γC4 in neurons and astrocytes.
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Affiliation(s)
- Celia P Miralles
- Department of Physiology and Neurobiology, University of Connecticut, Storrs, Connecticut, USA
| | - Michael J Taylor
- Department of Physiology and Neurobiology, University of Connecticut, Storrs, Connecticut, USA
| | - John Bear
- Department of Physiology and Neurobiology, University of Connecticut, Storrs, Connecticut, USA
| | - Christopher D Fekete
- Department of Physiology and Neurobiology, University of Connecticut, Storrs, Connecticut, USA
| | - Shanu George
- Department of Physiology and Neurobiology, University of Connecticut, Storrs, Connecticut, USA
| | - Yanfang Li
- Department of Physiology and Neurobiology, University of Connecticut, Storrs, Connecticut, USA
| | - Bevan Bonhomme
- Department of Physiology and Neurobiology, University of Connecticut, Storrs, Connecticut, USA
| | - Tzu-Ting Chiou
- Department of Physiology and Neurobiology, University of Connecticut, Storrs, Connecticut, USA
| | - Angel L De Blas
- Department of Physiology and Neurobiology, University of Connecticut, Storrs, Connecticut, USA
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15
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Chiou TT, Long P, Schumann-Gillett A, Kanamarlapudi V, Haas SA, Harvey K, O'Mara ML, De Blas AL, Kalscheuer VM, Harvey RJ. Mutation p.R356Q in the Collybistin Phosphoinositide Binding Site Is Associated With Mild Intellectual Disability. Front Mol Neurosci 2019; 12:60. [PMID: 30914922 PMCID: PMC6422930 DOI: 10.3389/fnmol.2019.00060] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2018] [Accepted: 02/19/2019] [Indexed: 11/13/2022] Open
Abstract
The recruitment of inhibitory GABAA receptors to neuronal synapses requires a complex interplay between receptors, neuroligins, the scaffolding protein gephyrin and the GDP-GTP exchange factor collybistin (CB). Collybistin is regulated by protein-protein interactions at the N-terminal SH3 domain, which can bind neuroligins 2/4 and the GABAAR α2 subunit. Collybistin also harbors a RhoGEF domain which mediates interactions with gephyrin and catalyzes GDP-GTP exchange on Cdc42. Lastly, collybistin has a pleckstrin homology (PH) domain, which binds phosphoinositides, such as phosphatidylinositol 3-phosphate (PI3P/PtdIns3P) and phosphatidylinositol 4-monophosphate (PI4P/PtdIns4P). PI3P located in early/sorting endosomes has recently been shown to regulate the postsynaptic clustering of gephyrin and GABAA receptors and consequently the strength of inhibitory synapses in cultured hippocampal neurons. This process is disrupted by mutations in the collybistin gene (ARHGEF9), which cause X-linked intellectual disability (XLID) by a variety of mechanisms converging on disrupted gephyrin and GABAA receptor clustering at central synapses. Here we report a novel missense mutation (chrX:62875607C>T, p.R356Q) in ARHGEF9 that affects one of the two paired arginine residues in the PH domain that were predicted to be vital for binding phosphoinositides. Functional assays revealed that recombinant collybistin CB3SH3- R356Q was deficient in PI3P binding and was not able to translocate EGFP-gephyrin to submembrane microaggregates in an in vitro clustering assay. Expression of the PI3P-binding mutants CB3SH3- R356Q and CB3SH3- R356N/R357N in cultured hippocampal neurones revealed that the mutant proteins did not accumulate at inhibitory synapses, but instead resulted in a clear decrease in the overall number of synaptic gephyrin clusters compared to controls. Molecular dynamics simulations suggest that the p.R356Q substitution influences PI3P binding by altering the range of structural conformations adopted by collybistin. Taken together, these results suggest that the p.R356Q mutation in ARHGEF9 is the underlying cause of XLID in the probands, disrupting gephyrin clustering at inhibitory GABAergic synapses via loss of collybistin PH domain phosphoinositide binding.
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Affiliation(s)
- Tzu-Ting Chiou
- Department of Physiology and Neurobiology, University of Connecticut, Storrs, CT, United States
| | - Philip Long
- Department of Pharmacology, UCL School of Pharmacy, London, United Kingdom
| | | | | | - Stefan A Haas
- Department of Computational Molecular Biology, Max Planck Institute for Molecular Genetics, Berlin, Germany
| | - Kirsten Harvey
- Department of Pharmacology, UCL School of Pharmacy, London, United Kingdom
| | - Megan L O'Mara
- Research School of Chemistry, The Australian National University, Canberra, ACT, Australia
| | - Angel L De Blas
- Department of Physiology and Neurobiology, University of Connecticut, Storrs, CT, United States
| | - Vera M Kalscheuer
- Group Development and Disease, Max Planck Institute for Molecular Genetics, Berlin, Germany
| | - Robert J Harvey
- School of Health and Sport Sciences, University of the Sunshine Coast, Sippy Downs, QLD, Australia.,Sunshine Coast Health Institute, Birtinya, QLD, Australia
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16
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Bassani S, Cwetsch AW, Gerosa L, Serratto GM, Folci A, Hall IF, Mazzanti M, Cancedda L, Passafaro M. The female epilepsy protein PCDH19 is a new GABAAR-binding partner that regulates GABAergic transmission as well as migration and morphological maturation of hippocampal neurons. Hum Mol Genet 2019; 27:1027-1038. [PMID: 29360992 PMCID: PMC5886308 DOI: 10.1093/hmg/ddy019] [Citation(s) in RCA: 47] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2017] [Accepted: 01/04/2018] [Indexed: 01/15/2023] Open
Abstract
The PCDH19 gene (Xp22.1) encodes the cell-adhesion protein protocadherin-19 (PCDH19) and is responsible for a neurodevelopmental pathology characterized by female-limited epilepsy, cognitive impairment and autistic features, the pathogenic mechanisms of which remain to be elucidated. Here, we identified a new interaction between PCDH19 and GABAA receptor (GABAAR) alpha subunits in the rat brain. PCDH19 shRNA-mediated downregulation reduces GABAAR surface expression and affects the frequency and kinetics of miniature inhibitory postsynaptic currents (mIPSCs) in cultured hippocampal neurons. In vivo, PCDH19 downregulation impairs migration, orientation and dendritic arborization of CA1 hippocampal neurons and increases rat seizure susceptibility. In sum, these data indicate a role for PCDH19 in GABAergic transmission as well as migration and morphological maturation of neurons.
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Affiliation(s)
| | - Andrzej W Cwetsch
- Department of Neuroscience and Brain Technologies, Istituto Italiano di Tecnologia, Genoa 16163, Italy
| | - Laura Gerosa
- CNR Institute of Neuroscience, Milan 20129, Italy
| | | | | | | | - Michele Mazzanti
- Department of Bioscience, University of Milan, Milan 20133, Italy
| | - Laura Cancedda
- Department of Neuroscience and Brain Technologies, Istituto Italiano di Tecnologia, Genoa 16163, Italy.,Telethon Dulbecco Institute, Milan, Italy
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17
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Hillen AEJ, Burbach JPH, Hol EM. Cell adhesion and matricellular support by astrocytes of the tripartite synapse. Prog Neurobiol 2018; 165-167:66-86. [PMID: 29444459 DOI: 10.1016/j.pneurobio.2018.02.002] [Citation(s) in RCA: 66] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2016] [Revised: 07/25/2017] [Accepted: 02/07/2018] [Indexed: 12/18/2022]
Abstract
Astrocytes contribute to the formation, function, and plasticity of synapses. Their processes enwrap the neuronal components of the tripartite synapse, and due to this close interaction they are perfectly positioned to modulate neuronal communication. The interaction between astrocytes and synapses is facilitated by cell adhesion molecules and matricellular proteins, which have been implicated in the formation and functioning of tripartite synapses. The importance of such neuron-astrocyte integration at the synapse is underscored by the emerging role of astrocyte dysfunction in synaptic pathologies such as autism and schizophrenia. Here we review astrocyte-expressed cell adhesion molecules and matricellular molecules that play a role in integration of neurons and astrocytes within the tripartite synapse.
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Affiliation(s)
- Anne E J Hillen
- Department of Translational Neuroscience, Brain Center Rudolf Magnus, University Medical Center Utrecht, 3584 CG Utrecht, The Netherlands; Department of Pediatrics/Child Neurology, VU University Medical Center, 1081 HV Amsterdam, The Netherlands
| | - J Peter H Burbach
- Department of Translational Neuroscience, Brain Center Rudolf Magnus, University Medical Center Utrecht, 3584 CG Utrecht, The Netherlands
| | - Elly M Hol
- Department of Translational Neuroscience, Brain Center Rudolf Magnus, University Medical Center Utrecht, 3584 CG Utrecht, The Netherlands; Swammerdam Institute for Life Sciences, Center for Neuroscience, University of Amsterdam, 1098 XH Amsterdam, The Netherlands; Department of Neuroimmunology, Netherlands Institute for Neuroscience, An Institute of the Royal Netherlands Academy of Arts and Sciences, 1105 BA Amsterdam, The Netherlands.
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18
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Functions and dysfunctions of Ca2+/calmodulin-dependent protein kinase phosphatase (CaMKP/PPM1F) and CaMKP-N/PPM1E. Arch Biochem Biophys 2018; 640:83-92. [DOI: 10.1016/j.abb.2018.01.001] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2017] [Revised: 12/28/2017] [Accepted: 01/04/2018] [Indexed: 12/22/2022]
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19
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Jha MK, Kim JH, Song GJ, Lee WH, Lee IK, Lee HW, An SSA, Kim S, Suk K. Functional dissection of astrocyte-secreted proteins: Implications in brain health and diseases. Prog Neurobiol 2017; 162:37-69. [PMID: 29247683 DOI: 10.1016/j.pneurobio.2017.12.003] [Citation(s) in RCA: 94] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2017] [Revised: 10/23/2017] [Accepted: 12/08/2017] [Indexed: 02/07/2023]
Abstract
Astrocytes, which are homeostatic cells of the central nervous system (CNS), display remarkable heterogeneity in their morphology and function. Besides their physical and metabolic support to neurons, astrocytes modulate the blood-brain barrier, regulate CNS synaptogenesis, guide axon pathfinding, maintain brain homeostasis, affect neuronal development and plasticity, and contribute to diverse neuropathologies via secreted proteins. The identification of astrocytic proteome and secretome profiles has provided new insights into the maintenance of neuronal health and survival, the pathogenesis of brain injury, and neurodegeneration. Recent advances in proteomics research have provided an excellent catalog of astrocyte-secreted proteins. This review categorizes astrocyte-secreted proteins and discusses evidence that astrocytes play a crucial role in neuronal activity and brain function. An in-depth understanding of astrocyte-secreted proteins and their pathways is pivotal for the development of novel strategies for restoring brain homeostasis, limiting brain injury/inflammation, counteracting neurodegeneration, and obtaining functional recovery.
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Affiliation(s)
- Mithilesh Kumar Jha
- Department of Pharmacology, Brain Science and Engineering Institute, BK21 Plus KNU Biomedical Convergence Program, Kyungpook National University School of Medicine, Daegu, Republic of Korea; Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Jong-Heon Kim
- Department of Pharmacology, Brain Science and Engineering Institute, BK21 Plus KNU Biomedical Convergence Program, Kyungpook National University School of Medicine, Daegu, Republic of Korea
| | - Gyun Jee Song
- Department of Pharmacology, Brain Science and Engineering Institute, BK21 Plus KNU Biomedical Convergence Program, Kyungpook National University School of Medicine, Daegu, Republic of Korea
| | - Won-Ha Lee
- School of Life Sciences, BK21 Plus KNU Creative BioResearch Group, Kyungpook National University, Daegu, Republic of Korea
| | - In-Kyu Lee
- Department of Internal Medicine, Division of Endocrinology and Metabolism, Kyungpook National University School of Medicine, Daegu, Republic of Korea
| | - Ho-Won Lee
- Department of Neurology, Brain Science and Engineering Institute, Kyungpook National University School of Medicine, Daegu, Republic of Korea
| | - Seong Soo A An
- Department of BioNano Technology, Gachon University, Gyeonggi-do, Republic of Korea
| | - SangYun Kim
- Department of Neurology, Seoul National University Bundang Hospital, Seoul National University College of Medicine, Gyeonggi-do, Republic of Korea
| | - Kyoungho Suk
- Department of Pharmacology, Brain Science and Engineering Institute, BK21 Plus KNU Biomedical Convergence Program, Kyungpook National University School of Medicine, Daegu, Republic of Korea.
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20
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Rossi A, Murta V, Auzmendi J, Ramos AJ. Early Gabapentin Treatment during the Latency Period Increases Convulsive Threshold, Reduces Microglial Activation and Macrophage Infiltration in the Lithium-Pilocarpine Model of Epilepsy. Pharmaceuticals (Basel) 2017; 10:ph10040093. [PMID: 29182533 PMCID: PMC5748648 DOI: 10.3390/ph10040093] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2017] [Revised: 11/14/2017] [Accepted: 11/19/2017] [Indexed: 12/20/2022] Open
Abstract
The lithium-pilocarpine model of epilepsy reproduces several features of temporal lobe epilepsy in humans, including the chronological timeline of an initial latency period followed by the development of spontaneous seizures. Epilepsy therapies in humans are implemented, as a rule, after the onset of the spontaneous seizures. We here studied the potential effect on epileptogenesis of starting an early treatment during the latency period, in order to prevent the development of spontaneous seizures. Adult male Wistar rats were treated with 3 mEq/kg LiCl, and 20 h later 30 mg/kg pilocarpine. Once status epilepticus (SE) was achieved, it was allowed to last for 20 min, and then motor seizures were controlled with the administration of 20 mg/kg diazepam. At 1DPSE (DPSE, days post-status epilepticus), animals started to receive 400 mg/kg/day gabapentin or saline for 4 days. At 5DPSE, we observed that SE induced an early profuse microglial and astroglial reactivity, increased synaptogenic trombospondin-1 expression and reduced AQP4 expression in astroglial ending feet. Blood brain barrier (BBB) integrity seemed to be compromised, as infiltrating NG2+ macrophages and facilitated access to the CNS was observed by transplanting eGFP+ blood cells and bone marrow-derived progenitors in the SE animals. The early 4-day gabapentin treatment successfully reduced microglial cell reactivity and blood-borne cell infiltration, without significantly altering the mRNA of proinflammatory cytokines IL-1β and TNFα immediately after the treatment. After 21DSPE, another group of animals that developed SE and received 4 days of gabapentin treatment, were re-exposed to subconvulsive accumulative doses of pilocarpine (10 mg/kg/30 min) and were followed by recording the Racine scale reached. Early 4-day gabapentin treatment reduced the Racine scale reached by the animals, reduced animal mortality, and reduced the number of animals that achieved SE (34% vs. 72%). We conclude that early gabapentin treatment following SE, during the latency period, is able to reduce neuroinflammation and produces a persistent effect that limits seizures and increases convulsive threshold, probably by restricting microglial reactivity and spurious synaptogenesis.
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Affiliation(s)
- Alicia Rossi
- Departamento de Histología, Embriología, Biología Celular y Genética, Facultad de Medicina, Universidad de Buenos Aires, Buenos Aires CP1121, Argentina.
- Laboratorio de Neuropatología Molecular, Instituto de Biología Celular y Neurociencia "Profesor E. De Robertis" IBCN UBA-CONICET, Buenos Aires CP1121, Argentina.
| | - Veronica Murta
- Laboratorio de Neuropatología Molecular, Instituto de Biología Celular y Neurociencia "Profesor E. De Robertis" IBCN UBA-CONICET, Buenos Aires CP1121, Argentina.
| | - Jerónimo Auzmendi
- Laboratorio de Neuropatología Molecular, Instituto de Biología Celular y Neurociencia "Profesor E. De Robertis" IBCN UBA-CONICET, Buenos Aires CP1121, Argentina.
| | - Alberto Javier Ramos
- Departamento de Histología, Embriología, Biología Celular y Genética, Facultad de Medicina, Universidad de Buenos Aires, Buenos Aires CP1121, Argentina.
- Laboratorio de Neuropatología Molecular, Instituto de Biología Celular y Neurociencia "Profesor E. De Robertis" IBCN UBA-CONICET, Buenos Aires CP1121, Argentina.
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21
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Peek SL, Mah KM, Weiner JA. Regulation of neural circuit formation by protocadherins. Cell Mol Life Sci 2017; 74:4133-4157. [PMID: 28631008 PMCID: PMC5643215 DOI: 10.1007/s00018-017-2572-3] [Citation(s) in RCA: 77] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2017] [Revised: 06/01/2017] [Accepted: 06/13/2017] [Indexed: 12/20/2022]
Abstract
The protocadherins (Pcdhs), which make up the most diverse group within the cadherin superfamily, were first discovered in the early 1990s. Data implicating the Pcdhs, including ~60 proteins encoded by the tandem Pcdha, Pcdhb, and Pcdhg gene clusters and another ~10 non-clustered Pcdhs, in the regulation of neural development have continually accumulated, with a significant expansion of the field over the past decade. Here, we review the many roles played by clustered and non-clustered Pcdhs in multiple steps important for the formation and function of neural circuits, including dendrite arborization, axon outgrowth and targeting, synaptogenesis, and synapse elimination. We further discuss studies implicating mutation or epigenetic dysregulation of Pcdh genes in a variety of human neurodevelopmental and neurological disorders. With recent structural modeling of Pcdh proteins, the prospects for uncovering molecular mechanisms of Pcdh extracellular and intracellular interactions, and their role in normal and disrupted neural circuit formation, are bright.
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Affiliation(s)
- Stacey L Peek
- Interdisciplinary Graduate Program in Neuroscience, The University of Iowa, Iowa City, IA, USA
- Department of Biology, The University of Iowa, Iowa City, IA, USA
| | - Kar Men Mah
- Department of Biology, The University of Iowa, Iowa City, IA, USA
| | - Joshua A Weiner
- Department of Biology, The University of Iowa, Iowa City, IA, USA.
- Department of Psychiatry, The University of Iowa, 143 Biology Building, Iowa City, IA, 52242, USA.
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Fekete CD, Goz RU, Dinallo S, Miralles CP, Chiou TT, Bear J, Fiondella CG, LoTurco JJ, De Blas AL. In vivo transgenic expression of collybistin in neurons of the rat cerebral cortex. J Comp Neurol 2016; 525:1291-1311. [PMID: 27804142 DOI: 10.1002/cne.24137] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2016] [Revised: 10/18/2016] [Accepted: 10/19/2016] [Indexed: 01/12/2023]
Abstract
Collybistin (CB) is a guanine nucleotide exchange factor selectively localized to γ-aminobutyric acid (GABA)ergic and glycinergic postsynapses. Active CB interacts with gephyrin, inducing the submembranous clustering and the postsynaptic accumulation of gephyrin, which is a scaffold protein that recruits GABAA receptors (GABAA Rs) at the postsynapse. CB is expressed with or without a src homology 3 (SH3) domain. We have previously reported the effects on GABAergic synapses of the acute overexpression of CBSH3- or CBSH3+ in cultured hippocampal (HP) neurons. In the present communication, we are studying the effects on GABAergic synapses after chronic in vivo transgenic expression of CB2SH3- or CB2SH3+ in neurons of the adult rat cerebral cortex. The embryonic precursors of these cortical neurons were in utero electroporated with CBSH3- or CBSH3+ DNAs, migrated to the appropriate cortical layer, and became integrated in cortical circuits. The results show that: 1) the strength of inhibitory synapses in vivo can be enhanced by increasing the expression of CB in neurons; and 2) there are significant differences in the results between in vivo and in culture studies. J. Comp. Neurol. 525:1291-1311, 2017. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- Christopher D Fekete
- Department of Physiology and Neurobiology, University of Connecticut, Storrs, Connecticut, 06269
| | - Roman U Goz
- Department of Physiology and Neurobiology, University of Connecticut, Storrs, Connecticut, 06269
| | - Sean Dinallo
- Department of Physiology and Neurobiology, University of Connecticut, Storrs, Connecticut, 06269
| | - Celia P Miralles
- Department of Physiology and Neurobiology, University of Connecticut, Storrs, Connecticut, 06269
| | - Tzu-Ting Chiou
- Department of Physiology and Neurobiology, University of Connecticut, Storrs, Connecticut, 06269
| | - John Bear
- Department of Physiology and Neurobiology, University of Connecticut, Storrs, Connecticut, 06269
| | - Christopher G Fiondella
- Department of Physiology and Neurobiology, University of Connecticut, Storrs, Connecticut, 06269
| | - Joseph J LoTurco
- Department of Physiology and Neurobiology, University of Connecticut, Storrs, Connecticut, 06269
| | - Angel L De Blas
- Department of Physiology and Neurobiology, University of Connecticut, Storrs, Connecticut, 06269
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de Wit J, Ghosh A. Specification of synaptic connectivity by cell surface interactions. Nat Rev Neurosci 2015; 17:22-35. [PMID: 26656254 DOI: 10.1038/nrn.2015.3] [Citation(s) in RCA: 192] [Impact Index Per Article: 21.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The molecular diversification of cell surface molecules has long been postulated to impart specific surface identities on neuronal cell types. The existence of unique cell surface identities would allow neurons to distinguish one another and connect with their appropriate target cells. Although progress has been made in identifying cell type-specific surface molecule repertoires and in characterizing their extracellular interactions, determining how this molecular diversity contributes to the precise wiring of neural circuitry has proven challenging. Here, we review the role of the cadherin, neurexin, immunoglobulin and leucine-rich repeat protein superfamilies in the specification of connectivity. The emerging evidence suggests that the concerted actions of these proteins may critically contribute to the assembly of neural circuits.
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Affiliation(s)
- Joris de Wit
- VIB Center for the Biology of Disease and Center for Human Genetics, KU Leuven, Herestraat 49, 3000 Leuven, Belgium
| | - Anirvan Ghosh
- Neuroscience Discovery, Roche Innovation Center Basel, F. Hoffman-La Roche, Grenzacherstrasse 124, 4070 Basel, Switzerland
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Heller JP, Rusakov DA. Morphological plasticity of astroglia: Understanding synaptic microenvironment. Glia 2015; 63:2133-51. [PMID: 25782611 PMCID: PMC4737250 DOI: 10.1002/glia.22821] [Citation(s) in RCA: 106] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2015] [Accepted: 03/02/2015] [Indexed: 12/27/2022]
Abstract
Memory formation in the brain is thought to rely on the remodeling of synaptic connections which eventually results in neural network rewiring. This remodeling is likely to involve ultrathin astroglial protrusions which often occur in the immediate vicinity of excitatory synapses. The phenomenology, cellular mechanisms, and causal relationships of such astroglial restructuring remain, however, poorly understood. This is in large part because monitoring and probing of the underpinning molecular machinery on the scale of nanoscopic astroglial compartments remains a challenge. Here we briefly summarize the current knowledge regarding the cellular organisation of astroglia in the synaptic microenvironment and discuss molecular mechanisms potentially involved in use-dependent astroglial morphogenesis. We also discuss recent observations concerning morphological astroglial plasticity, the respective monitoring methods, and some of the newly emerging techniques that might help with conceptual advances in the area.
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Affiliation(s)
- Janosch P Heller
- Department of Clinical and Experimental Epilepsy, UCL Institute of Neurology, University College London, Queen Square, London, United Kingdom
| | - Dmitri A Rusakov
- Department of Clinical and Experimental Epilepsy, UCL Institute of Neurology, University College London, Queen Square, London, United Kingdom
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Onouchi T, Kishino-Kaneko Y, Kameshita I, Ishida A, Sueyoshi N. Regulation of Ca(2+)/calmodulin-dependent protein kinase phosphatase (CaMKP/PPM1F) by protocadherin-γC5 (Pcdh-γC5). Arch Biochem Biophys 2015; 585:109-120. [PMID: 26386307 DOI: 10.1016/j.abb.2015.09.014] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2015] [Revised: 09/15/2015] [Accepted: 09/15/2015] [Indexed: 01/14/2023]
Abstract
Ca(2+)/calmodulin-dependent protein kinase phosphatase (CaMKP/PPM1F) is a Ser/Thr protein phosphatase that belongs to the PPM family. It is important to identify an endogenous regulator of CaMKP. Using an Escherichia coli two-hybrid screening method, we identified the C-terminal cytoplasmic fragment of protocadherin γ subfamily C5 (Pcdh-γC5), which was generated by intracellular processing, as a CaMKP-binding protein. Dephosphorylation of phosphorylated Ca(2+)/calmodulin-dependent protein kinase I (CaMKI) by CaMKP was significantly activated by the C-terminal cytoplasmic fragment, Pcdh-γC5(715-944), both in vitro and in cells, suggesting that the C-terminal fragment functions as an endogenous activator of CaMKP. The nuclear translocation of the fragment was blocked by its binding to cytoplasmic CaMKP to form a ternary complex with CaMKI. Taken together, these results strongly suggest that the C-terminal cytoplasmic fragment of Pcdh-γC5 acts as a scaffold for CaMKP and CaMKI to regulate CaMKP activity. These findings may provide new insights into the reversible regulation of CaMKP in cells.
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Affiliation(s)
- Takashi Onouchi
- Department of Life Sciences, Faculty of Agriculture, Kagawa University, Kagawa 761-0795, Japan
| | - Yoshimi Kishino-Kaneko
- Department of Life Sciences, Faculty of Agriculture, Kagawa University, Kagawa 761-0795, Japan
| | - Isamu Kameshita
- Department of Life Sciences, Faculty of Agriculture, Kagawa University, Kagawa 761-0795, Japan
| | - Atsuhiko Ishida
- Laboratory of Molecular Brain Science, Graduate School of Integrated Arts and Sciences, Hiroshima University, Higashi-Hiroshima 739-8521, Japan.
| | - Noriyuki Sueyoshi
- Department of Life Sciences, Faculty of Agriculture, Kagawa University, Kagawa 761-0795, Japan.
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Mariman ECM, Szklarczyk R, Bouwman FG, Aller EEJG, van Baak MA, Wang P. Olfactory receptor genes cooperate with protocadherin genes in human extreme obesity. GENES AND NUTRITION 2015; 10:465. [PMID: 25943692 PMCID: PMC4420755 DOI: 10.1007/s12263-015-0465-3] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/19/2015] [Accepted: 04/21/2015] [Indexed: 01/28/2023]
Abstract
Worldwide, the incidence of obesity has increased dramatically over the past decades. More knowledge about the complex etiology of obesity is needed in order to find additional approaches for treatment and prevention. Investigating the exome sequencing data of 30 extremely obese subjects (BMI 45-65 kg/m(2)) shows that predicted damaging missense variants in olfactory receptor genes on chromosome 1q and rare predicted damaging variants in the protocadherin (PCDH) beta-cluster genes on chromosome 5q31, reported in our previous work, co-localize in subjects with extreme obesity. This implies a synergistic effect between genetic variation in these gene clusters in the predisposition to extreme obesity. Evidence for a general involvement of the olfactory transduction pathway on itself could not be found. Bioinformatic analysis indicates a specific involvement of the PCDH beta-cluster genes in controlling tissue development. Further mechanistic insight needs to await the identification of the ligands of the 1q olfactory receptors. Eventually, this may provide the possibility to manipulate food flavor in a way to reduce the risk of overeating and of extreme obesity in genetically predisposed subjects.
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Affiliation(s)
- Edwin C M Mariman
- Department of Human Biology, NUTRIM School for Nutrition, Toxicology and Metabolism, Maastricht University Medical Centre, Maastricht, The Netherlands,
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Keeler AB, Molumby MJ, Weiner JA. Protocadherins branch out: Multiple roles in dendrite development. Cell Adh Migr 2015; 9:214-26. [PMID: 25869446 DOI: 10.1080/19336918.2014.1000069] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
The proper formation of dendritic arbors is a critical step in neural circuit formation, and as such defects in arborization are associated with a variety of neurodevelopmental disorders. Among the best gene candidates are those encoding cell adhesion molecules, including members of the diverse cadherin superfamily characterized by distinctive, repeated adhesive domains in their extracellular regions. Protocadherins (Pcdhs) make up the largest group within this superfamily, encompassing over 80 genes, including the ∼60 genes of the α-, β-, and γ-Pcdh gene clusters and the non-clustered δ-Pcdh genes. An additional group includes the atypical cadherin genes encoding the giant Fat and Dachsous proteins and the 7-transmembrane cadherins. In this review we highlight the many roles that Pcdhs and atypical cadherins have been demonstrated to play in dendritogenesis, dendrite arborization, and dendritic spine regulation. Together, the published studies we discuss implicate these members of the cadherin superfamily as key regulators of dendrite development and function, and as potential therapeutic targets for future interventions in neurodevelopmental disorders.
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Key Words
- CNR, Cadherin related neuronal receptor
- CTCF, CCCTC-binding factor
- CaMKII, Ca2+/calmodulin-dependent protein kinase II.
- Celsr, Cadherin EGF LAG 7-pass G-type receptor 1
- DSCAM, Down syndrome cell adhesion molecule
- Dnmt3b, DNA (cytosine-5-)-methyltransferase 3 β
- Ds, Dachsous
- EC, extracellular cadherin
- EGF, Epidermal growth factor
- FAK, Focal adhesion kinase
- FMRP, Fragile X mental retardation protein
- Fj, Four jointed
- Fjx1, Four jointed box 1
- GPCR, G-protein-coupled receptor
- Gogo, Golden Goal
- LIM domain, Lin11, Isl-1 & Mec-3 domain
- MARCKS, Myristoylated alanine-rich C-kinase substrate
- MEF2, Myocyte enhancer factor 2
- MEK3, Mitogen-activated protein kinase kinase 3
- PCP, planar cell polarity
- PKC, Protein kinase C
- PSD, Post-synaptic density
- PYK2, Protein tyrosine kinase 2
- Pcdh
- Pcdh, Protocadherin
- RGC, Retinal ganglion cell
- RNAi, RNA interference
- Rac1, Ras-related C3 botulinum toxin substrate 1
- S2 cells, Schneider 2 cells
- SAC, starburst amacrine cell
- TAF1, Template-activating factor 1
- TAO2β, Thousand and one amino acid protein kinase 2 β
- TM, transmembrane
- arborization
- atypical cadherin
- branching
- cadherin superfamily
- cell adhesion
- da neuron, dendritic arborization neuron
- dendritic
- dendritic spine
- dendritogenesis
- fmi, Flamingo
- md neuron, multiple dendrite neuron
- neural circuit formation
- p38 MAPK, p38 mitogen-activated protein kinase
- self avoidance
- synaptogenesis
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Affiliation(s)
- Austin B Keeler
- a Department of Biology ; Neuroscience Graduate Program; University of Iowa ; Iowa City , IA USA
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Fekete CD, Chiou TT, Miralles CP, Harris RS, Fiondella CG, Loturco JJ, De Blas AL. In vivo clonal overexpression of neuroligin 3 and neuroligin 2 in neurons of the rat cerebral cortex: Differential effects on GABAergic synapses and neuronal migration. J Comp Neurol 2015; 523:1359-78. [PMID: 25565602 DOI: 10.1002/cne.23740] [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] [Received: 09/18/2014] [Revised: 01/02/2015] [Accepted: 01/02/2015] [Indexed: 01/08/2023]
Abstract
We studied the effect of clonal overexpression of neuroligin 3 (NL3) or neuroligin 2 (NL2) in the adult rat cerebral cortex following in utero electroporation (IUEP) at embryonic stage E14. Overexpression of NL3 leads to a large increase in vesicular gamma-aminobutyric acid (GABA) transporter (vGAT) and glutamic acid decarboxylase (GAD)65 in the GABAergic contacts that the overexpressing neurons receive. Overexpression of NL2 produced a similar effect but to a lesser extent. In contrast, overexpression of NL3 or NL2 after IUEP does not affect vesicular glutamate transporter 1 (vGlut1) in the glutamatergic contacts that the NL3 or NL2-overexpressing neurons receive. The NL3 or NL2-overexpressing neurons do not show increased innervation by parvalbumin-containing GABAergic terminals or increased parvalbumin in the same terminals that show increased vGAT. These results indicate that the observed increase in vGAT and GAD65 is not due to increased GABAergic innervation but to increased expression of vGAT and GAD65 in the GABAergic contacts that NL3 or NL2-overexpressing neurons receive. The majority of bright vGAT puncta contacting the NL3-overexpressing neurons have no gephyrin juxtaposed to them, indicating that many of these contacts are nonsynaptic. This contrasts with the majority of the NL2-overexpressing neurons, which show plenty of synaptic gephyrin clusters juxtaposed to vGAT. Besides having an effect on GABAergic contacts, overexpression of NL3 interferes with the neuronal radial migration, in the cerebral cortex, of the neurons overexpressing NL3.
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Affiliation(s)
- Christopher D Fekete
- Department of Physiology and Neurobiology, University of Connecticut, Storrs, Connecticut, 06269
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Jin H, Chiou TT, Serwanski DR, Miralles CP, Pinal N, De Blas AL. Ring finger protein 34 (RNF34) interacts with and promotes γ-aminobutyric acid type-A receptor degradation via ubiquitination of the γ2 subunit. J Biol Chem 2014; 289:29420-36. [PMID: 25193658 DOI: 10.1074/jbc.m114.603068] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
We have found that the large intracellular loop of the γ2 GABAA receptor (R) subunit (γ2IL) interacts with RNF34 (an E3 ubiquitin ligase), as shown by yeast two-hybrid and in vitro pulldown assays. In brain extracts, RNF34 co-immunoprecipitates with assembled GABAARs. In co-transfected HEK293 cells, RNF34 reduces the expression of the γ2 GABAAR subunit by increasing the ratio of ubiquitinated/nonubiquitinated γ2. Mutating several lysines of the γ2IL into arginines makes the γ2 subunit resistant to RNF34-induced degradation. RNF34 also reduces the expression of the γ2 subunit when α1 and β3 subunits are co-assembled with γ2. This effect is partially reversed by leupeptin or MG132, indicating that both the lysosomal and proteasomal degradation pathways are involved. Immunofluorescence of cultured hippocampal neurons shows that RNF34 forms clusters and that a subset of these clusters is associated with GABAergic synapses. This association is also observed in the intact rat brain by electron microscopy immunocytochemistry. RNF34 is not expressed until the 2nd postnatal week of rat brain development, being highly expressed in some interneurons. Overexpression of RNF34 in hippocampal neurons decreases the density of γ2 GABAAR clusters and the number of GABAergic contacts that these neurons receive. Knocking down endogenous RNF34 with shRNA leads to increased γ2 GABAAR cluster density and GABAergic innervation. The results indicate that RNF34 regulates postsynaptic γ2-GABAAR clustering and GABAergic synaptic innervation by interacting with and ubiquitinating the γ2-GABAAR subunit promoting GABAAR degradation.
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Affiliation(s)
- Hongbing Jin
- From the Department of Physiology and Neurobiology, University of Connecticut, Storrs, Connecticut 06269
| | - Tzu-Ting Chiou
- From the Department of Physiology and Neurobiology, University of Connecticut, Storrs, Connecticut 06269
| | - David R Serwanski
- From the Department of Physiology and Neurobiology, University of Connecticut, Storrs, Connecticut 06269
| | - Celia P Miralles
- From the Department of Physiology and Neurobiology, University of Connecticut, Storrs, Connecticut 06269
| | - Noelia Pinal
- From the Department of Physiology and Neurobiology, University of Connecticut, Storrs, Connecticut 06269
| | - Angel L De Blas
- From the Department of Physiology and Neurobiology, University of Connecticut, Storrs, Connecticut 06269
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Eagleson KL, Milner TA, Xie Z, Levitt P. Synaptic and extrasynaptic location of the receptor tyrosine kinase met during postnatal development in the mouse neocortex and hippocampus. J Comp Neurol 2014; 521:3241-59. [PMID: 23787772 DOI: 10.1002/cne.23343] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2012] [Revised: 02/13/2013] [Accepted: 04/05/2013] [Indexed: 12/13/2022]
Abstract
MET, a replicated autism risk gene, encodes a pleiotropic receptor tyrosine kinase implicated in multiple cellular processes during development and following injury. Previous studies suggest that Met modulates excitatory synapse development in the neocortex and hippocampus, although the underlying mechanism is unknown. The peak of Met expression corresponds to the period of process outgrowth and synaptogenesis, with robust expression in hippocampal and neocortical neuropil. Resolving whether neuropil expression represents presynaptic, postsynaptic or glial localization provides insight into potential mechanisms of Met action. The subcellular distribution of Met was characterized using complementary ultrastructural, in situ proximity ligation assay (PLA), and biochemical approaches. At postnatal day (P) 7, immunoelectron microscopy revealed near-equivalent proportions of Met-immunoreactive pre- (axons and terminals) and postsynaptic (dendritic shafts and spines) profiles in the stratum radiatum in the hippocampal CA1 region. Staining was typically in elements in which the corresponding pre- or postsynaptic apposition was unlabeled. By P21, Met-immunoreactive presynaptic profiles predominated and ~20% of Met-expressing profiles were glial. A different distribution of Met-immunoreactive profiles was observed in layer V of somatosensory cortex: Met-labeled spines were rare and a smaller proportion of glial profiles expressed Met. Strikingly, Met-immunoreactive presynaptic profiles predominated over postsynaptic profiles as early as P7. PLA analysis of neurons in vitro and biochemical analysis of tissue subsynaptic fractions confirmed the localization of Met in specific synaptic subcompartments. The study demonstrates that Met is enriched at synapses during development and its activation may modulate synapse formation and stability through both pre- and postsynaptic mechanisms.
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Affiliation(s)
- Kathie L Eagleson
- Zilkha Neurogenetic Institute, Keck School of Medicine of USC, Los Angeles, California 90033, USA.
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Paul D, Ge S, Lemire Y, Jellison ER, Serwanski DR, Ruddle NH, Pachter JS. Cell-selective knockout and 3D confocal image analysis reveals separate roles for astrocyte-and endothelial-derived CCL2 in neuroinflammation. J Neuroinflammation 2014; 11:10. [PMID: 24444311 PMCID: PMC3906899 DOI: 10.1186/1742-2094-11-10] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2013] [Accepted: 12/28/2013] [Indexed: 12/30/2022] Open
Abstract
Background Expression of chemokine CCL2 in the normal central nervous system (CNS) is nearly undetectable, but is significantly upregulated and drives neuroinflammation during experimental autoimmune encephalomyelitis (EAE), an animal model of multiple sclerosis which is considered a contributing factor in the human disease. As astrocytes and brain microvascular endothelial cells (BMEC) forming the blood–brain barrier (BBB) are sources of CCL2 in EAE and other neuroinflammatory conditions, it is unclear if one or both CCL2 pools are critical to disease and by what mechanism(s). Methods Mice with selective CCL2 gene knockout (KO) in astrocytes (Astro KO) or endothelial cells (Endo KO) were used to evaluate the respective contributions of these sources to neuroinflammation, i.e., clinical disease progression, BBB damage, and parenchymal leukocyte invasion in a myelin oligodendrocyte glycoprotein peptide (MOG35-55)-induced EAE model. High-resolution 3-dimensional (3D) immunofluorescence confocal microscopy and colloidal gold immuno-electron microscopy were employed to confirm sites of CCL2 expression, and 3D immunofluorescence confocal microscopy utilized to assess inflammatory responses along the CNS microvasculature. Results Cell-selective loss of CCL2 immunoreactivity was demonstrated in the respective KO mice. Compared to wild-type (WT) mice, Astro KO mice showed reduced EAE severity but similar onset, while Endo KO mice displayed near normal severity but significantly delayed onset. Neither of the KO mice showed deficits in T cell proliferation, or IL-17 and IFN-γ production, following MOG35-55 exposure in vitro, or altered MOG-major histocompatibility complex class II tetramer binding. 3D confocal imaging further revealed distinct actions of the two CCL2 pools in the CNS. Astro KOs lacked the CNS leukocyte penetration and disrupted immunostaining of CLN-5 at the BBB seen during early EAE in WT mice, while Endo KOs uniquely displayed leukocytes stalled in the microvascular lumen. Conclusions These results point to astrocyte and endothelial pools of CCL2 each regulating different stages of neuroinflammation in EAE, and carry implications for drug delivery in neuroinflammatory disease.
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Affiliation(s)
| | - Shujun Ge
- Department of Cell Biology, Blood-brain Barrier Laboratory, 263 Farmington Ave,, Farmington CT 06030, USA.
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Abstract
The function and efficacy of synaptic transmission are determined not only by the composition and activity of pre- and postsynaptic components but also by the environment in which a synapse is embedded. Glial cells constitute an important part of this environment and participate in several aspects of synaptic functions. Among the glial cell family, the roles played by astrocytes at the synaptic level are particularly important, ranging from the trophic support to the fine-tuning of transmission. Astrocytic structures are frequently observed in close association with glutamatergic synapses, providing a morphological entity for bidirectional interactions with synapses. Experimental evidence indicates that astrocytes sense neuronal activity by elevating their intracellular calcium in response to neurotransmitters and may communicate with neurons. The precise role of astrocytes in regulating synaptic properties, function, and plasticity remains however a subject of intense debate and many aspects of their interactions with neurons remain to be investigated. A particularly intriguing aspect is their ability to rapidly restructure their processes and modify their coverage of the synaptic elements. The present review summarizes some of these findings with a particular focus on the mechanisms driving this form of structural plasticity and its possible impact on synaptic structure and function.
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Liang CL, Marks GA. GABAA receptors are located in cholinergic terminals in the nucleus pontis oralis of the rat: Implications for REM sleep control. Brain Res 2014; 1543:58-64. [DOI: 10.1016/j.brainres.2013.10.019] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2013] [Revised: 10/02/2013] [Accepted: 10/10/2013] [Indexed: 10/26/2022]
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Ledderose J, Dieter S, Schwarz MK. Maturation of postnatally generated olfactory bulb granule cells depends on functional γ-protocadherin expression. Sci Rep 2013; 3:1514. [PMID: 23515096 PMCID: PMC3604712 DOI: 10.1038/srep01514] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2013] [Accepted: 03/06/2013] [Indexed: 11/20/2022] Open
Abstract
γ-protocadherins (γ-pcdhs) are transmembrane receptor proteins ubiquitously expressed in the postnatal and adult mouse brain. γ-pcdhs are required for normal neuronal development as shown for spinal cord interneurons, retinal ganglion cells and cortical neurons. To test the role of γ-pcdhs during development of subventricular zone progenitor cells and their subsequent differentiation into olfactory granule cells we generated a conditional γ-pcdhlox/lox allele (γ-pcdhlox/lox) allowing for functional γ-pcdh inactivation upon lentivirus-mediated Cre-recombinase expression selectively in subventricular zone progenitor cells. While γ-pcdh loss did not alter the proliferation of subventricular zone progenitors, γ-pcdh ko progenitors that reached the main olfactory bulb showed a significant reduction in dendritic arborization and failed to develop dendritic spines. Our results suggest that olfactory bulb granule cell maturation necessitates functional γ-pcdh expression.
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Affiliation(s)
- Julia Ledderose
- Max Planck Institute for Medical Research, Jahnstr. 29, 69120 Heidelberg, Germany.
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35
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Cox DJ, Racca C. Differential dendritic targeting of AMPA receptor subunit mRNAs in adult rat hippocampal principal neurons and interneurons. J Comp Neurol 2013; 521:1954-2007. [DOI: 10.1002/cne.23292] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2011] [Revised: 12/13/2012] [Accepted: 12/14/2012] [Indexed: 12/19/2022]
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Abstract
We have found that the γ2 subunit of the GABA(A) receptor (γ2-GABA(A)R) specifically interacts with protocadherin-γC5 (Pcdh-γC5) in the rat brain. The interaction occurs between the large intracellular loop of the γ2-GABA(A)R and the cytoplasmic domain of Pcdh-γC5. In brain extracts, Pcdh-γC5 coimmunoprecipitates with GABA(A)Rs. In cotransfected HEK293 cells, Pcdh-γC5 promotes the transfer of γ2-GABA(A)R to the cell surface. We have previously shown that, in cultured hippocampal neurons, endogenous Pcdh-γC5 forms clusters, some of which associate with GABAergic synapses. Overexpression of Pcdh-γC5 in hippocampal neurons increases the density of γ2-GABA(A)R clusters but has no significant effect on the number of GABAergic contacts that these neurons receive, indicating that Pcdh-γC5 is not synaptogenic. Deletion of the cytoplasmic domain of Pcdh-γC5 enhanced its surface expression but decreased the association with both γ2-GABA(A)R clusters and presynaptic GABAergic contacts. Cultured hippocampal neurons from the Pcdh-γ triple C-type isoform knock-out (TCKO) mouse (Pcdhg(tcko/tcko)) showed plenty of GABAergic synaptic contacts, although their density was reduced compared with sister cultures from wild-type and heterozygous mice. Knocking down Pcdh-γC5 expression with shRNA decreased γ2-GABA(A)R cluster density and GABAergic innervation. The results indicate that, although Pcdh-γC5 is not essential for GABAergic synapse formation or GABA(A)R clustering, (1) Pcdh-γC5 regulates the surface expression of GABA(A)Rs via cis-cytoplasmic interaction with γ2-GABA(A)R, and (2) Pcdh-γC5 plays a role in the stabilization and maintenance of some GABAergic synapses.
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Abstract
Cadherins are Ca(2+)-dependent cell-cell adhesion molecules that play critical roles in animal morphogenesis. Various cadherin-related molecules have also been identified, which show diverse functions, not only for the regulation of cell adhesion but also for that of cell proliferation and planar cell polarity. During the past decade, understanding of the roles of these molecules in the nervous system has significantly progressed. They are important not only for the development of the nervous system but also for its functions and, in turn, for neural disorders. In this review, we discuss the roles of cadherins and related molecules in neural development and function in the vertebrate brain.
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Affiliation(s)
- Shinji Hirano
- Department of Neurobiology and Anatomy, Kochi Medical School, Okoh-cho Kohasu, Nankoku-City 783–8505, Japan.
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Harris KM, Weinberg RJ. Ultrastructure of synapses in the mammalian brain. Cold Spring Harb Perspect Biol 2012; 4:cshperspect.a005587. [PMID: 22357909 DOI: 10.1101/cshperspect.a005587] [Citation(s) in RCA: 275] [Impact Index Per Article: 22.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The morphology and molecular composition of synapses provide the structural basis for synaptic function. This article reviews the electron microscopy of excitatory synapses on dendritic spines, using data from rodent hippocampus, cerebral cortex, and cerebellar cortex. Excitatory synapses have a prominent postsynaptic density, in contrast with inhibitory synapses, which have less dense presynaptic or postsynaptic specializations and are usually found on the cell body or proximal dendritic shaft. Immunogold labeling shows that the presynaptic active zone provides a scaffold for key molecules involved in the release of neurotransmitter, whereas the postsynaptic density contains ligand-gated ionic channels, other receptors, and a complex network of signaling molecules. Delineating the structure and molecular organization of these axospinous synapses represents a crucial step toward understanding the mechanisms that underlie synaptic transmission and the dynamic modulation of neurotransmission associated with short- and long-term synaptic plasticity.
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Affiliation(s)
- Kristen M Harris
- Center for Learning and Memory, Neurobiology Section, University of Texas, Austin, 78712, USA.
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Chiou TT, Bonhomme B, Jin H, Miralles CP, Xiao H, Fu Z, Harvey RJ, Harvey K, Vicini S, De Blas AL. Differential regulation of the postsynaptic clustering of γ-aminobutyric acid type A (GABAA) receptors by collybistin isoforms. J Biol Chem 2011; 286:22456-68. [PMID: 21540179 DOI: 10.1074/jbc.m111.236190] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Collybistin promotes submembrane clustering of gephyrin and is essential for the postsynaptic localization of gephyrin and γ-aminobutyric acid type A (GABA(A)) receptors at GABAergic synapses in hippocampus and amygdala. Four collybistin isoforms are expressed in brain neurons; CB2 and CB3 differ in the C terminus and occur with and without the Src homology 3 (SH3) domain. We have found that in transfected hippocampal neurons, all collybistin isoforms (CB2(SH3+), CB2(SH3-), CB3(SH3+), and CB3(SH3-)) target to and concentrate at GABAergic postsynapses. Moreover, in non-transfected neurons, collybistin concentrates at GABAergic synapses. Hippocampal neurons co-transfected with CB2(SH3-) and gephyrin developed very large postsynaptic gephyrin and GABA(A) receptor clusters (superclusters). This effect was accompanied by a significant increase in the amplitude of miniature inhibitory postsynaptic currents. Co-transfection with CB2(SH3+) and gephyrin induced the formation of many (supernumerary) non-synaptic clusters. Transfection with gephyrin alone did not affect cluster number or size, but gephyrin potentiated the clustering effect of CB2(SH3-) or CB2(SH3+). Co-transfection with CB2(SH3-) or CB2(SH3+) and gephyrin did not affect the density of presynaptic GABAergic terminals contacting the transfected cells, indicating that collybistin is not synaptogenic. Nevertheless, the synaptic superclusters induced by CB2(SH3-) and gephyrin were accompanied by enlarged presynaptic GABAergic terminals. The enhanced clustering of gephyrin and GABA(A) receptors induced by collybistin isoforms was not accompanied by enhanced clustering of neuroligin 2. Moreover, during the development of GABAergic synapses, the clustering of gephyrin and GABA(A) receptors preceded the clustering of neuroligin 2. We propose a model in which the SH3- isoforms play a major role in the postsynaptic accumulation of GABA(A) receptors and in GABAergic synaptic strength.
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Affiliation(s)
- Tzu-Ting Chiou
- Department of Physiology and Neurobiology, University of Connecticut, Storrs, Connecticut 06269, USA
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Abstract
Synaptic junctions are generated by adhesion proteins that bridge the synaptic cleft to firmly anchor pre- and postsynaptic membranes. Several cell adhesion molecule (CAM) families localize to synapses, but it is not yet completely understood how each synaptic CAM family contributes to synapse formation and/or structure, and whether or how smaller groups of CAMs serve as minimal, functionally cooperative adhesive units upon which structure is based. Synapse structure and function evolve over the course of development, and in mature animals, synapses are composed of a greater number of proteins, surrounded by a stabilizing extracellular matrix, and often contacted by astrocytic processes. Thus, in mature networks undergoing plasticity, persistent changes in synapse strength, morphology, or number must be accompanied by selective and regulated remodeling of the neuropil. Recent work indicates that regulated, extracellular proteolysis may be essential for this, and rather than simply acting permissively to enable synapse plasticity, is more likely playing a proactive role in driving coordinated synaptic structural and functional modifications that underlie persistent changes in network activity.
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Affiliation(s)
- Deanna L Benson
- Fishberg Department of Neuroscience and Friedman Brain Institute, Mount Sinai School of Medicine, New York, New York 10029, USA.
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