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Wang X, Lin D, Jiang J, Liu Y, Dong X, Fan J, Gong L, Shen W, Zeng L, Xu T, Jiang K, Connor SA, Xie Y. MDGA2 Constrains Glutamatergic Inputs Selectively onto CA1 Pyramidal Neurons to Optimize Neural Circuits for Plasticity, Memory, and Social Behavior. Neurosci Bull 2024; 40:887-904. [PMID: 38321347 PMCID: PMC11250762 DOI: 10.1007/s12264-023-01171-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2023] [Accepted: 10/08/2023] [Indexed: 02/08/2024] Open
Abstract
Synapse organizers are essential for the development, transmission, and plasticity of synapses. Acting as rare synapse suppressors, the MAM domain containing glycosylphosphatidylinositol anchor (MDGA) proteins contributes to synapse organization by inhibiting the formation of the synaptogenic neuroligin-neurexin complex. A previous analysis of MDGA2 mice lacking a single copy of Mdga2 revealed upregulated glutamatergic synapses and behaviors consistent with autism. However, MDGA2 is expressed in diverse cell types and is localized to both excitatory and inhibitory synapses. Differentiating the network versus cell-specific effects of MDGA2 loss-of-function requires a cell-type and brain region-selective strategy. To address this, we generated mice harboring a conditional knockout of Mdga2 restricted to CA1 pyramidal neurons. Here we report that MDGA2 suppresses the density and function of excitatory synapses selectively on pyramidal neurons in the mature hippocampus. Conditional deletion of Mdga2 in CA1 pyramidal neurons of adult mice upregulated miniature and spontaneous excitatory postsynaptic potentials, vesicular glutamate transporter 1 intensity, and neuronal excitability. These effects were limited to glutamatergic synapses as no changes were detected in miniature and spontaneous inhibitory postsynaptic potential properties or vesicular GABA transporter intensity. Functionally, evoked basal synaptic transmission and AMPAR receptor currents were enhanced at glutamatergic inputs. At a behavioral level, memory appeared to be compromised in Mdga2 cKO mice as both novel object recognition and contextual fear conditioning performance were impaired, consistent with deficits in long-term potentiation in the CA3-CA1 pathway. Social affiliation, a behavioral analog of social deficits in autism, was similarly compromised. These results demonstrate that MDGA2 confines the properties of excitatory synapses to CA1 neurons in mature hippocampal circuits, thereby optimizing this network for plasticity, cognition, and social behaviors.
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Affiliation(s)
- Xuehui Wang
- School of Life Sciences, Nanchang University, Nanchang, 330031, China
- Department of Neurology, Children's Hospital, Zhejiang University School of Medicine, National Clinical Research Center for Child Health, Hangzhou, 310052, China
| | - Donghui Lin
- Department of Neurology, Children's Hospital, Zhejiang University School of Medicine, National Clinical Research Center for Child Health, Hangzhou, 310052, China
| | - Jie Jiang
- Department of Neurology, Children's Hospital, Zhejiang University School of Medicine, National Clinical Research Center for Child Health, Hangzhou, 310052, China
- Department of Biology, York University, 4700 Keele Street, Toronto, ON, M3J 1P3, Canada
| | - Yuhua Liu
- School of Life Sciences, Nanchang University, Nanchang, 330031, China
- Department of Neurology, Children's Hospital, Zhejiang University School of Medicine, National Clinical Research Center for Child Health, Hangzhou, 310052, China
| | - Xinyan Dong
- Department of Neurology, Children's Hospital, Zhejiang University School of Medicine, National Clinical Research Center for Child Health, Hangzhou, 310052, China
| | - Jianchen Fan
- Key Laboratory of Novel Targets and Drug Study for Neural Repair of Zhejiang Province, School of Medicine, Hangzhou City University, Hangzhou, 310015, China
| | - Lifen Gong
- Department of Neurology, Children's Hospital, Zhejiang University School of Medicine, National Clinical Research Center for Child Health, Hangzhou, 310052, China
| | - Weida Shen
- Key Laboratory of Novel Targets and Drug Study for Neural Repair of Zhejiang Province, School of Medicine, Hangzhou City University, Hangzhou, 310015, China
| | - Linghui Zeng
- Key Laboratory of Novel Targets and Drug Study for Neural Repair of Zhejiang Province, School of Medicine, Hangzhou City University, Hangzhou, 310015, China
| | - Tonghui Xu
- School of Life Sciences, Nanchang University, Nanchang, 330031, China
| | - Kewen Jiang
- Department of Neurology, Children's Hospital, Zhejiang University School of Medicine, National Clinical Research Center for Child Health, Hangzhou, 310052, China.
| | - Steven A Connor
- Department of Biology, York University, 4700 Keele Street, Toronto, ON, M3J 1P3, Canada.
| | - Yicheng Xie
- School of Life Sciences, Nanchang University, Nanchang, 330031, China.
- Department of Neurology, Children's Hospital, Zhejiang University School of Medicine, National Clinical Research Center for Child Health, Hangzhou, 310052, China.
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Sekine K, Haga W, Kim S, Imayasu M, Yoshida T, Tsutsui H. Neuron-microelectrode junction induced by an engineered synapse organizer. Biochem Biophys Res Commun 2024; 712-713:149935. [PMID: 38626529 DOI: 10.1016/j.bbrc.2024.149935] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2024] [Revised: 04/04/2024] [Accepted: 04/11/2024] [Indexed: 04/18/2024]
Abstract
The conventional microelectrodes for recording neuronal activities do not have innate selectivity to cell type, which is one of the critical limitations for the detailed analysis of neuronal circuits. In this study, we engineered a downsized variant of the artificial synapse organizer based on neurexin1β and a peptide-tag, fabricated gold microelectrodes functionalized with the receptor for the organizer, and performed validation experiments in primary cultured neurons. Successful inductions of synapse-like junctions were detected at the sites of contact between neurons expressing the engineered synapse organizer and functionalized microelectrodes, but not in the negative control experiment in which the electrode functionalization was omitted. Such a molecularly inducible neuron-microelectrode junction could be the basis for the next-generation electrophysiological technique enabling cell type-selective recording.
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Affiliation(s)
- Kosuke Sekine
- School of Materials Science, Japan Advanced Institute of Science and Technology, Nomi, Ishikawa, 923-1292, Japan
| | - Wataru Haga
- School of Materials Science, Japan Advanced Institute of Science and Technology, Nomi, Ishikawa, 923-1292, Japan
| | - Samyoung Kim
- School of Materials Science, Japan Advanced Institute of Science and Technology, Nomi, Ishikawa, 923-1292, Japan
| | - Mieko Imayasu
- School of Materials Science, Japan Advanced Institute of Science and Technology, Nomi, Ishikawa, 923-1292, Japan
| | - Tomoyuki Yoshida
- Department of Molecular Neuroscience, Faculty of Medicine, University of Toyama, Toyama, 930-0194, Japan; Research Center for Idling Brain Science, University of Toyama, Toyama, 930-0194, Japan
| | - Hidekazu Tsutsui
- School of Materials Science, Japan Advanced Institute of Science and Technology, Nomi, Ishikawa, 923-1292, Japan; Division of Transdisciplinary Sciences, Japan Advanced Institute of Science and Technology, Nomi, Ishikawa, 923-1292, Japan.
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3
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DePew AT, Bruckner JJ, O'Connor-Giles KM, Mosca TJ. Neuronal LRP4 directs the development, maturation and cytoskeletal organization of Drosophila peripheral synapses. Development 2024; 151:dev202517. [PMID: 38738619 PMCID: PMC11190576 DOI: 10.1242/dev.202517] [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: 11/09/2023] [Accepted: 05/02/2024] [Indexed: 05/14/2024]
Abstract
Synaptic development requires multiple signaling pathways to ensure successful connections. Transmembrane receptors are optimally positioned to connect the synapse and the rest of the neuron, often acting as synaptic organizers to synchronize downstream events. One such organizer, the LDL receptor-related protein LRP4, is a cell surface receptor that has been most well-studied postsynaptically at mammalian neuromuscular junctions. Recent work, however, identified emerging roles, but how LRP4 acts as a presynaptic organizer and the downstream mechanisms of LRP4 are not well understood. Here, we show that LRP4 functions presynaptically at Drosophila neuromuscular synapses, acting in motoneurons to instruct pre- and postsynaptic development. Loss of presynaptic LRP4 results in multiple defects, impairing active zone organization, synapse growth, physiological function, microtubule organization, synaptic ultrastructure and synapse maturation. We further demonstrate that LRP4 promotes most aspects of presynaptic development via a downstream SR-protein kinase, SRPK79D. These data demonstrate a function for presynaptic LRP4 as a peripheral synaptic organizer, highlight a downstream mechanism conserved with its CNS function in Drosophila, and underscore previously unappreciated but important developmental roles for LRP4 in cytoskeletal organization, synapse maturation and active zone organization.
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Affiliation(s)
- Alison T. DePew
- Department of Neuroscience, Vickie and Jack Farber Institute of Neuroscience, Thomas Jefferson University, Philadelphia, PA 19107, USA
| | - Joseph J. Bruckner
- Cell and Molecular Biology Training Program, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Kate M. O'Connor-Giles
- Department of Neuroscience, Brown University, Providence, RI 02912, USA
- Carney Institute for Brain Science, Brown University, Providence, RI 02912, USA
| | - Timothy J. Mosca
- Department of Neuroscience, Vickie and Jack Farber Institute of Neuroscience, Thomas Jefferson University, Philadelphia, PA 19107, USA
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4
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Haga W, Sekine K, Hamid SA, Imayasu M, Yoshida T, Tsutsui H. Development of artificial synapse organizers liganded with a peptide tag for molecularly inducible neuron-microelectrode interface. Biochem Biophys Res Commun 2024; 699:149563. [PMID: 38277728 DOI: 10.1016/j.bbrc.2024.149563] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2024] [Accepted: 01/20/2024] [Indexed: 01/28/2024]
Abstract
It has been proposed that cell-type-specific bioelectronic interfaces for neuronal circuits could be established by utilizing the function of synapse organizers. For this purpose, using neurexin-1β and a peptide tag, we engineered compact synapse organizers that do not interact with the naturally occurring receptors but induce presynaptic differentiation upon contact with nanobody-decorated objects in cultured mammalian and chick forebrain neurons. In chick neurons, the engineered organizer exerted synaptogenesis typically in ∼4 h after the contact, even under an air atmosphere at room temperature, thereby providing a useful cellular model for establishing the molecularly inducible neuron-microelectrode interface.
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Affiliation(s)
- Wataru Haga
- School of Materials Science, Japan Advanced Institute of Science and Technology, Nomi, Ishikawa, 923-1292, Japan
| | - Kosuke Sekine
- School of Materials Science, Japan Advanced Institute of Science and Technology, Nomi, Ishikawa, 923-1292, Japan
| | - Sm Ahasanul Hamid
- School of Materials Science, Japan Advanced Institute of Science and Technology, Nomi, Ishikawa, 923-1292, Japan
| | - Mieko Imayasu
- School of Materials Science, Japan Advanced Institute of Science and Technology, Nomi, Ishikawa, 923-1292, Japan
| | - Tomoyuki Yoshida
- Department of Molecular Neuroscience, Faculty of Medicine, University of Toyama, Toyama, 930-0194, Japan; Research Center for Idling Brain Science, University of Toyama, Toyama, 930-0194, Japan
| | - Hidekazu Tsutsui
- School of Materials Science, Japan Advanced Institute of Science and Technology, Nomi, Ishikawa, 923-1292, Japan; Division of Transdisciplinary Sciences, Japan Advanced Institute of Science and Technology, Nomi, Ishikawa, 923-1292, Japan.
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5
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Sciandra F, Bozzi M, Bigotti MG. From adhesion complex to signaling hub: the dual role of dystroglycan. Front Mol Biosci 2023; 10:1325284. [PMID: 38155958 PMCID: PMC10752950 DOI: 10.3389/fmolb.2023.1325284] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2023] [Accepted: 11/27/2023] [Indexed: 12/30/2023] Open
Abstract
Dystroglycan (DG) is a transmembrane protein widely expressed in multiple cells and tissues. It is formed by two subunits, α- and β-DG, and represents a molecular bridge between the outside and the inside of the cell, which is essential for the mechanical and structural stability of the plasma membrane. The α-subunit is a cell-surface protein that binds to the extracellular matrix (ECM) and is tightly associated with the plasma membrane via a non-covalent interaction with the β-subunit, which, in turn, is a transmembrane protein that binds to the cytoskeletal actin. DG is a versatile molecule acting not only as a mechanical building block but also as a modulator of outside-inside signaling events. The cytoplasmic domain of β-DG interacts with different adaptor and cytoskeletal proteins that function as molecular switches for the transmission of ECM signals inside the cells. These interactions can modulate the involvement of DG in different biological processes, ranging from cell growth and survival to differentiation and proliferation/regeneration. Although the molecular events that characterize signaling through the ECM-DG-cytoskeleton axis are still largely unknown, in recent years, a growing list of evidence has started to fill the gaps in our understanding of the role of DG in signal transduction. This mini-review represents an update of recent developments, uncovering the dual role of DG as an adhesion and signaling molecule that might inspire new ideas for the design of novel therapeutic strategies for pathologies such as muscular dystrophy, cardiomyopathy, and cancer, where the DG signaling hub plays important roles.
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Affiliation(s)
- Francesca Sciandra
- Istituto di Scienze e Tecnologie Chimiche “Giulio Natta”-SCITEC (CNR), Roma, Italy
| | - Manuela Bozzi
- Istituto di Scienze e Tecnologie Chimiche “Giulio Natta”-SCITEC (CNR), Roma, Italy
- Dipartimento di Scienze Biotecnologiche di Base, Cliniche Intensivologiche e Perioperatorie, Sezione di Biochimica, Università Cattolica del Sacro Cuore di Roma, Roma, Italy
| | - Maria Giulia Bigotti
- School of Biochemistry, University of Bristol, Bristol, United Kingdom
- Bristol Heart Institute, Research Floor Level 7, Bristol Royal Infirmary, Bristol, United Kingdom
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6
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Frankel EB, Tiroumalechetty A, Henry PS, Su Z, Wu Y, Kurshan PT. Protein-lipid interactions drive presynaptic assembly upstream of cell adhesion molecules. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.11.17.567618. [PMID: 38014115 PMCID: PMC10680821 DOI: 10.1101/2023.11.17.567618] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/29/2023]
Abstract
Textbook models of synaptogenesis position cell adhesion molecules such as neurexin as initiators of synapse assembly. Here we discover a mechanism for presynaptic assembly that occurs prior to neurexin recruitment, while supporting a role for neurexin in synapse maintenance. We find that the cytosolic active zone scaffold SYD-1 interacts with membrane phospholipids to promote active zone protein clustering at the plasma membrane, and subsequently recruits neurexin to stabilize those clusters. Employing molecular dynamics simulations to model intrinsic interactions between SYD-1 and lipid bilayers followed by in vivo tests of these predictions, we find that PIP2-interacting residues in SYD-1's C2 and PDZ domains are redundantly necessary for proper active zone assembly. Finally, we propose that the uncharacterized yet evolutionarily conserved short γ isoform of neurexin represents a minimal neurexin sequence that can stabilize previously assembled presynaptic clusters, potentially a core function of this critical protein.
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Affiliation(s)
- Elisa B Frankel
- Department of Neuroscience, Albert Einstein College of Medicine, Bronx, NY 10461
| | | | - Parise S Henry
- Department of Neuroscience, Albert Einstein College of Medicine, Bronx, NY 10461
| | - Zhaoqian Su
- Data Science Institute, Vanderbilt University, 1001 19th Ave S, Nashville, TN, 37212
| | - Yinghao Wu
- Department of Systems and Computational Biology, Albert Einstein College of Medicine, Bronx, NY 10461
| | - Peri T Kurshan
- Department of Neuroscience, Albert Einstein College of Medicine, Bronx, NY 10461
- Lead Contact
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7
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DePew AT, Bruckner JJ, O’Connor-Giles KM, Mosca TJ. Neuronal LRP4 directs the development, maturation, and cytoskeletal organization of peripheral synapses. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.11.03.564481. [PMID: 37961323 PMCID: PMC10635100 DOI: 10.1101/2023.11.03.564481] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2023]
Abstract
Synapse development requires multiple signaling pathways to accomplish the myriad of steps needed to ensure a successful connection. Transmembrane receptors on the cell surface are optimally positioned to facilitate communication between the synapse and the rest of the neuron and often function as synaptic organizers to synchronize downstream signaling events. One such organizer, the LDL receptor-related protein LRP4, is a cell surface receptor most well-studied postsynaptically at mammalian neuromuscular junctions. Recent work, however, has identified emerging roles for LRP4 as a presynaptic molecule, but how LRP4 acts as a presynaptic organizer, what roles LRP4 plays in organizing presynaptic biology, and the downstream mechanisms of LRP4 are not well understood. Here we show that LRP4 functions presynaptically at Drosophila neuromuscular synapses, acting in motor neurons to instruct multiple aspects of pre- and postsynaptic development. Loss of presynaptic LRP4 results in a range of developmental defects, impairing active zone organization, synapse growth, physiological function, microtubule organization, synaptic ultrastructure, and synapse maturation. We further demonstrate that LRP4 promotes most aspects of presynaptic development via a downstream SR-protein kinase, SRPK79D. SRPK79D overexpression suppresses synaptic defects associated with loss of lrp4. These data demonstrate a function for LRP4 as a peripheral synaptic organizer acting presynaptically, highlight a downstream mechanism conserved with its CNS function, and indicate previously unappreciated roles for LRP4 in cytoskeletal organization, synapse maturation, and active zone organization, underscoring its developmental importance.
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Affiliation(s)
- Alison T. DePew
- Dept. of Neuroscience, Vickie and Jack Farber Institute of Neuroscience, Thomas Jefferson University, Philadelphia, PA 19107 USA
| | - Joseph J. Bruckner
- Cell and Molecular Biology Training Program, University of Wisconsin-Madison, Madison, WI 53706 USA
| | - Kate M. O’Connor-Giles
- Department of Neuroscience, Brown University, Providence, RI 02912 USA
- Carney Institute for Brain Science, Brown University, Providence, RI 02912, USA
| | - Timothy J. Mosca
- Dept. of Neuroscience, Vickie and Jack Farber Institute of Neuroscience, Thomas Jefferson University, Philadelphia, PA 19107 USA
- Lead Contact
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8
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Aimino MA, Humenik J, Parisi MJ, Duhart JC, Mosca TJ. SynLight: a bicistronic strategy for simultaneous active zone and cell labeling in the Drosophila nervous system. G3 (BETHESDA, MD.) 2023; 13:jkad221. [PMID: 37757863 PMCID: PMC10627267 DOI: 10.1093/g3journal/jkad221] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/14/2023] [Revised: 07/14/2023] [Accepted: 09/17/2023] [Indexed: 09/29/2023]
Abstract
At synapses, chemical neurotransmission mediates the exchange of information between neurons, leading to complex movement, behaviors, and stimulus processing. The immense number and variety of neurons within the nervous system make discerning individual neuron populations difficult, necessitating the development of advanced neuronal labeling techniques. In Drosophila, Bruchpilot-Short and mCD8-GFP, which label presynaptic active zones and neuronal membranes, respectively, have been widely used to study synapse development and organization. This labeling is often achieved via the expression of 2 independent constructs by a single binary expression system, but expression can weaken when multiple transgenes are expressed by a single driver. Recent work has sought to circumvent these drawbacks by developing methods that encode multiple proteins from a single transcript. Self-cleaving peptides, specifically 2A peptides, have emerged as effective sequences for accomplishing this task. We leveraged 2A ribosomal skipping peptides to engineer a construct that produces both Bruchpilot-Short-mStraw and mCD8-GFP from the same mRNA, which we named SynLight. Using SynLight, we visualized the putative synaptic active zones and membranes of multiple classes of olfactory, visual, and motor neurons and observed the correct separation of signal, confirming that both proteins are being generated separately. Furthermore, we demonstrate proof of principle by quantifying synaptic puncta number and neurite volume in olfactory neurons and finding no difference between the synapse densities of neurons expressing SynLight or neurons expressing both transgenes separately. At the neuromuscular junction, we determined that the synaptic puncta number labeled by SynLight was comparable to the endogenous puncta labeled by antibody staining. Overall, SynLight is a versatile tool for examining synapse density in any nervous system region of interest and allows new questions to be answered about synaptic development and organization.
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Affiliation(s)
- Michael A Aimino
- Department of Neuroscience, Vickie and Jack Farber Institute of Neuroscience, Thomas Jefferson University, Bluemle Life Sciences Building, Philadelphia, PA 19107, USA
| | - Jesse Humenik
- Department of Neuroscience, Vickie and Jack Farber Institute of Neuroscience, Thomas Jefferson University, Bluemle Life Sciences Building, Philadelphia, PA 19107, USA
| | - Michael J Parisi
- Department of Neuroscience, Vickie and Jack Farber Institute of Neuroscience, Thomas Jefferson University, Bluemle Life Sciences Building, Philadelphia, PA 19107, USA
| | - Juan Carlos Duhart
- Department of Neuroscience, Vickie and Jack Farber Institute of Neuroscience, Thomas Jefferson University, Bluemle Life Sciences Building, Philadelphia, PA 19107, USA
| | - Timothy J Mosca
- Department of Neuroscience, Vickie and Jack Farber Institute of Neuroscience, Thomas Jefferson University, Bluemle Life Sciences Building, Philadelphia, PA 19107, USA
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9
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Michel JC, Grivette MMB, Harshfield AT, Huynh L, Komons AP, Loomis B, McKinnis K, Miller BT, Nguyen EQ, Huang TW, Lauf S, Michel ES, Michel ME, Kissinger JS, Marsh AJ, Crow WE, Kaye LE, Lasseigne AM, Lukowicz-Bedford RM, Farnsworth DR, Martin EA, Miller AC. Electrical synapse structure requires distinct isoforms of a postsynaptic scaffold. PLoS Genet 2023; 19:e1011045. [PMID: 38011265 PMCID: PMC10703405 DOI: 10.1371/journal.pgen.1011045] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2023] [Revised: 12/07/2023] [Accepted: 11/01/2023] [Indexed: 11/29/2023] Open
Abstract
Electrical synapses are neuronal gap junction (GJ) channels associated with a macromolecular complex called the electrical synapse density (ESD), which regulates development and dynamically modifies electrical transmission. However, the proteomic makeup and molecular mechanisms utilized by the ESD that direct electrical synapse formation are not well understood. Using the Mauthner cell of zebrafish as a model, we previously found that the intracellular scaffolding protein ZO1b is a member of the ESD, localizing postsynaptically, where it is required for GJ channel localization, electrical communication, neural network function, and behavior. Here, we show that the complexity of the ESD is further diversified by the genomic structure of the ZO1b gene locus. The ZO1b gene is alternatively initiated at three transcriptional start sites resulting in isoforms with unique N-termini that we call ZO1b-Alpha, -Beta, and -Gamma. We demonstrate that ZO1b-Beta and ZO1b-Gamma are broadly expressed throughout the nervous system and localize to electrical synapses. By contrast, ZO1b-Alpha is expressed mainly non-neuronally and is not found at synapses. We generate mutants in all individual isoforms, as well as double mutant combinations in cis on individual chromosomes, and find that ZO1b-Beta is necessary and sufficient for robust GJ channel localization. ZO1b-Gamma, despite its localization to the synapse, plays an auxiliary role in channel localization. This study expands the notion of molecular complexity at the ESD, revealing that an individual genomic locus can contribute distinct isoforms to the macromolecular complex at electrical synapses. Further, independent scaffold isoforms have differential contributions to developmental assembly of the interneuronal GJ channels. We propose that ESD molecular complexity arises both from the diversity of unique genes and from distinct isoforms encoded by single genes. Overall, ESD proteomic diversity is expected to have critical impacts on the development, structure, function, and plasticity of electrical transmission.
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Affiliation(s)
- Jennifer Carlisle Michel
- Institute of Neuroscience, Department of Biology, University of Oregon, Eugene, Oregon, United States of America
| | - Margaret M. B. Grivette
- Institute of Neuroscience, Department of Biology, University of Oregon, Eugene, Oregon, United States of America
| | - Amber T. Harshfield
- Institute of Neuroscience, Department of Biology, University of Oregon, Eugene, Oregon, United States of America
| | - Lisa Huynh
- Institute of Neuroscience, Department of Biology, University of Oregon, Eugene, Oregon, United States of America
| | - Ava P. Komons
- Institute of Neuroscience, Department of Biology, University of Oregon, Eugene, Oregon, United States of America
| | - Bradley Loomis
- Institute of Neuroscience, Department of Biology, University of Oregon, Eugene, Oregon, United States of America
| | - Kaitlan McKinnis
- Institute of Neuroscience, Department of Biology, University of Oregon, Eugene, Oregon, United States of America
| | - Brennen T. Miller
- Institute of Neuroscience, Department of Biology, University of Oregon, Eugene, Oregon, United States of America
| | - Ethan Q. Nguyen
- Institute of Neuroscience, Department of Biology, University of Oregon, Eugene, Oregon, United States of America
| | - Tiffany W. Huang
- Institute of Neuroscience, Department of Biology, University of Oregon, Eugene, Oregon, United States of America
| | - Sophia Lauf
- Institute of Neuroscience, Department of Biology, University of Oregon, Eugene, Oregon, United States of America
| | - Elias S. Michel
- Institute of Neuroscience, Department of Biology, University of Oregon, Eugene, Oregon, United States of America
| | - Mia E. Michel
- Institute of Neuroscience, Department of Biology, University of Oregon, Eugene, Oregon, United States of America
| | - Jane S. Kissinger
- Institute of Neuroscience, Department of Biology, University of Oregon, Eugene, Oregon, United States of America
| | - Audrey J. Marsh
- Institute of Neuroscience, Department of Biology, University of Oregon, Eugene, Oregon, United States of America
| | - William E. Crow
- Institute of Neuroscience, Department of Biology, University of Oregon, Eugene, Oregon, United States of America
| | - Lila E. Kaye
- Institute of Neuroscience, Department of Biology, University of Oregon, Eugene, Oregon, United States of America
| | - Abagael M. Lasseigne
- Institute of Neuroscience, Department of Biology, University of Oregon, Eugene, Oregon, United States of America
| | - Rachel M. Lukowicz-Bedford
- Institute of Neuroscience, Department of Biology, University of Oregon, Eugene, Oregon, United States of America
| | - Dylan R. Farnsworth
- Institute of Neuroscience, Department of Biology, University of Oregon, Eugene, Oregon, United States of America
| | - E. Anne Martin
- Institute of Neuroscience, Department of Biology, University of Oregon, Eugene, Oregon, United States of America
| | - Adam C. Miller
- Institute of Neuroscience, Department of Biology, University of Oregon, Eugene, Oregon, United States of America
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10
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Terauchi A, Yee P, Johnson-Venkatesh EM, Seiglie MP, Kim L, Pitino JC, Kritzer E, Zhang Q, Zhou J, Li Y, Ginty DD, Lee WCA, Umemori H. The projection-specific signals that establish functionally segregated dopaminergic synapses. Cell 2023; 186:3845-3861.e24. [PMID: 37591240 PMCID: PMC10540635 DOI: 10.1016/j.cell.2023.07.023] [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: 08/10/2022] [Revised: 05/28/2023] [Accepted: 07/14/2023] [Indexed: 08/19/2023]
Abstract
Dopaminergic projections regulate various brain functions and are implicated in many neuropsychiatric disorders. There are two anatomically and functionally distinct dopaminergic projections connecting the midbrain to striatum: nigrostriatal, which controls movement, and mesolimbic, which regulates motivation. However, how these discrete dopaminergic synaptic connections are established is unknown. Through an unbiased search, we identify that two groups of antagonistic TGF-β family members, bone morphogenetic protein (BMP)6/BMP2 and transforming growth factor (TGF)-β2, regulate dopaminergic synapse development of nigrostriatal and mesolimbic neurons, respectively. Projection-preferential expression of their receptors contributes to specific synapse development. Downstream, Smad1 and Smad2 are specifically activated and required for dopaminergic synapse development and function in nigrostriatal vs. mesolimbic projections. Remarkably, Smad1 mutant mice show motor defects, whereas Smad2 mutant mice show lack of motivation. These results uncover the molecular logic underlying the proper establishment of functionally segregated dopaminergic synapses and may provide strategies to treat relevant, projection-specific disease symptoms by targeting specific BMPs/TGF-β and/or Smads.
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Affiliation(s)
- Akiko Terauchi
- Department of Neurology, F.M. Kirby Neurobiology Center, Boston Children's Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Patricia Yee
- Department of Neurology, F.M. Kirby Neurobiology Center, Boston Children's Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Erin M Johnson-Venkatesh
- Department of Neurology, F.M. Kirby Neurobiology Center, Boston Children's Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Mariel P Seiglie
- Department of Neurology, F.M. Kirby Neurobiology Center, Boston Children's Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Lisa Kim
- Department of Neurology, F.M. Kirby Neurobiology Center, Boston Children's Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Julia C Pitino
- Department of Neurology, F.M. Kirby Neurobiology Center, Boston Children's Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Eli Kritzer
- Department of Neurology, F.M. Kirby Neurobiology Center, Boston Children's Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Qiyu Zhang
- Department of Neurobiology and Howard Hughes Medical Institute, Harvard Medical School, Boston, MA 02115, USA
| | - Jie Zhou
- Department of Computer Science, Northern Illinois University, DeKalb, IL 60115, USA
| | - Yulong Li
- State Key Laboratory of Membrane Biology, PKU-IDG/McGovern Institute for Brain Research, Peking-Tsinghua Center for Life Sciences, Peking University, Beijing 100871, China
| | - David D Ginty
- Department of Neurobiology and Howard Hughes Medical Institute, Harvard Medical School, Boston, MA 02115, USA
| | - Wei-Chung A Lee
- Department of Neurology, F.M. Kirby Neurobiology Center, Boston Children's Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Hisashi Umemori
- Department of Neurology, F.M. Kirby Neurobiology Center, Boston Children's Hospital, Harvard Medical School, Boston, MA 02115, USA.
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11
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Aimino MA, Humenik J, Parisi MJ, Duhart JC, Mosca TJ. SynLight: a dicistronic strategy for simultaneous active zone and cell labeling in the Drosophila nervous system. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.07.17.549367. [PMID: 37502901 PMCID: PMC10370149 DOI: 10.1101/2023.07.17.549367] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/29/2023]
Abstract
At synapses, chemical neurotransmission mediates the exchange of information between neurons, leading to complex movement behaviors and stimulus processing. The immense number and variety of neurons within the nervous system makes discerning individual neuron populations difficult, necessitating the development of advanced neuronal labeling techniques. In Drosophila , Bruchpilot-Short and mCD8-GFP, which label presynaptic active zones and neuronal membranes, respectively, have been widely used to study synapse development and organization. This labeling is often achieved via expression of two independent constructs by a single binary expression system, but expression can weaken when multiple transgenes are expressed by a single driver. Ensuring adequate expression of each transgene is essential to enable more complex experiments; as such, work has sought to circumvent these drawbacks by developing methods that encode multiple proteins from a single transcript. Self-cleaving peptides, specifically 2A peptides, have emerged as effective sequences for accomplishing this task. We leveraged 2A ribosomal skipping peptides to engineer a construct that produces both Bruchpilot-Short and mCD8-GFP from the same mRNA, which we named SynLight. Using SynLight, we visualized the putative synaptic active zones and membranes of multiple classes of olfactory, visual, and motor neurons and observed correct separation of signal, confirming that both proteins are being generated separately. Furthermore, we demonstrate proof-of-principle by quantifying synaptic puncta number and neurite volume in olfactory neurons and finding no difference between the synapse densities of neurons expressing SynLight or neurons expressing both transgenes separately. At the neuromuscular junction, we determined that synaptic puncta number labeled by SynLight was comparable to endogenous puncta labeled by antibody staining. Overall, SynLight is a versatile tool for examining synapse density in any nervous system region of interest and allows new questions to be answered about synaptic development and organization.
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Affiliation(s)
- Michael A. Aimino
- Department of Neuroscience, Vickie and Jack Farber Institute of Neuroscience, Thomas Jefferson University, Bluemle Life Sciences Building, Philadelphia, PA 19107
| | - Jesse Humenik
- Department of Neuroscience, Vickie and Jack Farber Institute of Neuroscience, Thomas Jefferson University, Bluemle Life Sciences Building, Philadelphia, PA 19107
| | - Michael J. Parisi
- Department of Neuroscience, Vickie and Jack Farber Institute of Neuroscience, Thomas Jefferson University, Bluemle Life Sciences Building, Philadelphia, PA 19107
| | - Juan Carlos Duhart
- Department of Neuroscience, Vickie and Jack Farber Institute of Neuroscience, Thomas Jefferson University, Bluemle Life Sciences Building, Philadelphia, PA 19107
| | - Timothy J. Mosca
- Department of Neuroscience, Vickie and Jack Farber Institute of Neuroscience, Thomas Jefferson University, Bluemle Life Sciences Building, Philadelphia, PA 19107
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12
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Okuno Y, Sakoori K, Matsuyama K, Yamasaki M, Watanabe M, Hashimoto K, Watanabe T, Kano M. PTPδ is a presynaptic organizer for the formation and maintenance of climbing fiber to Purkinje cell synapses in the developing cerebellum. Front Mol Neurosci 2023; 16:1206245. [PMID: 37426069 PMCID: PMC10323364 DOI: 10.3389/fnmol.2023.1206245] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2023] [Accepted: 05/25/2023] [Indexed: 07/11/2023] Open
Abstract
Functionally mature neural circuits are shaped during postnatal development by eliminating redundant synapses formed during the perinatal period. In the cerebellum of neonatal rodents, each Purkinje cell (PC) receives synaptic inputs from multiple (more than 4) climbing fibers (CFs). During the first 3 postnatal weeks, synaptic inputs from a single CF become markedly larger and those from the other CFs are eliminated in each PC, leading to mono-innervation of each PC by a strong CF in adulthood. While molecules involved in the strengthening and elimination of CF synapses during postnatal development are being elucidated, much less is known about the molecular mechanisms underlying CF synapse formation during the early postnatal period. Here, we show experimental evidence that suggests that a synapse organizer, PTPδ, is required for early postnatal CF synapse formation and the subsequent establishment of CF to PC synaptic wiring. We showed that PTPδ was localized at CF-PC synapses from postnatal day 0 (P0) irrespective of the expression of Aldolase C (Aldoc), a major marker of PC that distinguishes the cerebellar compartments. We found that the extension of a single strong CF along PC dendrites (CF translocation) was impaired in global PTPδ knockout (KO) mice from P12 to P29-31 predominantly in PCs that did not express Aldoc [Aldoc (-) PCs]. We also demonstrated via morphological and electrophysiological analyses that the number of CFs innervating individual PCs in PTPδ KO mice were fewer than in wild-type (WT) mice from P3 to P13 with a significant decrease in the strength of CF synaptic inputs in cerebellar anterior lobules where most PCs are Aldoc (-). Furthermore, CF-specific PTPδ-knockdown (KD) caused a reduction in the number of CFs innervating PCs with decreased CF synaptic inputs at P10-13 in anterior lobules. We found a mild impairment of motor performance in adult PTPδ KO mice. These results indicate that PTPδ acts as a presynaptic organizer for CF-PC formation and is required for normal CF-PC synaptic transmission, CF translocation, and presumably CF synapse maintenance predominantly in Aldoc (-) PCs. Furthermore, this study suggests that the impaired CF-PC synapse formation and development by the lack of PTPδ causes mild impairment of motor performance.
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Affiliation(s)
- Yuto Okuno
- Department of Neurophysiology, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
| | - Kazuto Sakoori
- Department of Neurophysiology, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
| | - Kyoko Matsuyama
- Department of Neurophysiology, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
| | - Miwako Yamasaki
- Department of Anatomy, Hokkaido University Graduate School of Medicine, Sapporo, Japan
| | - Masahiko Watanabe
- Department of Anatomy, Hokkaido University Graduate School of Medicine, Sapporo, Japan
| | - Kouichi Hashimoto
- Department of Neurophysiology, Graduate School of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan
| | - Takaki Watanabe
- Department of Neurophysiology, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
- International Research Center for Neurointelligence (WPI-IRCN), The University of Tokyo Institutes for Advanced Study, The University of Tokyo, Tokyo, Japan
| | - Masanobu Kano
- Department of Neurophysiology, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
- International Research Center for Neurointelligence (WPI-IRCN), The University of Tokyo Institutes for Advanced Study, The University of Tokyo, Tokyo, Japan
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13
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Schilling S, Pradhan A, Heesch A, Helbig A, Blennow K, Koch C, Bertgen L, Koo EH, Brinkmalm G, Zetterberg H, Kins S, Eggert S. Differential effects of familial Alzheimer's disease-causing mutations on amyloid precursor protein (APP) trafficking, proteolytic conversion, and synaptogenic activity. Acta Neuropathol Commun 2023; 11:87. [PMID: 37259128 DOI: 10.1186/s40478-023-01577-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2023] [Accepted: 05/04/2023] [Indexed: 06/02/2023] Open
Abstract
The amyloid precursor protein (APP) is a key player in Alzheimer`s disease (AD) and the precursor of the Aβ peptide, which is generated by consecutive cleavages of β- and γ-secretases. Familial Alzheimer's disease (FAD) describes a hereditary subgroup of AD that represents a low percentage of AD cases with an early onset of the disease. Different APP FAD mutations are thought to have qualitatively different effects on its proteolytic conversion. However, few studies have explored the pathogenic and putative physiological differences in more detail. Here, we compared different FAD mutations, located at the β- (Swedish), α- (Flemish, Arctic, Iowa) or γ-secretase (Iberian) cleavage sites. We examined heterologous expression of APP WT and FAD mutants in non-neuronal cells and their impact on presynaptic differentiation in contacting axons of co-cultured neurons. To decipher the underlying molecular mechanism, we tested the subcellular localization, the endocytosis rate and the proteolytic processing in detail by immunoprecipitation-mass spectrometry. Interestingly, we found that only the Iberian mutation showed altered synaptogenic function. Furthermore, the APP Iowa mutant shows significantly decreased α-secretase processing which is in line with our results that APP carrying the Iowa mutation was significantly increased in early endosomes. However, most interestingly, immunoprecipitation-mass spectrometry analysis revealed that the amino acid substitutions of APP FAD mutants have a decisive impact on their processing reflected in altered Aβ profiles. Importantly, N-terminally truncated Aβ peptides starting at position 5 were detected preferentially for APP Flemish, Arctic, and Iowa mutants containing amino acid substitutions around the α-secretase cleavage site. The strongest change in the ratio of Aβ40/Aβ42 was observed for the Iberian mutation while APP Swedish showed a substantial increase in Aβ1-17 peptides. Together, our data indicate that familial AD mutations located at the α-, β-, and γ-secretase cleavage sites show considerable differences in the underlying pathogenic mechanisms.
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Affiliation(s)
- Sandra Schilling
- Department of Human Biology and Human Genetics, University of Kaiserslautern, 67663, Kaiserslautern, Germany
| | - Ajay Pradhan
- Department of Psychiatry and Neurochemistry, Institute of Neuroscience and Physiology, The Sahlgrenska Academy at the University of Gothenburg, Mölndal, Sweden
| | - Amelie Heesch
- Department of Human Biology and Human Genetics, University of Kaiserslautern, 67663, Kaiserslautern, Germany
| | - Andrea Helbig
- Department of Human Biology and Human Genetics, University of Kaiserslautern, 67663, Kaiserslautern, Germany
| | - Kaj Blennow
- Department of Psychiatry and Neurochemistry, Institute of Neuroscience and Physiology, The Sahlgrenska Academy at the University of Gothenburg, Mölndal, Sweden
| | - Christian Koch
- Department of Human Biology and Human Genetics, University of Kaiserslautern, 67663, Kaiserslautern, Germany
| | - Lea Bertgen
- Department of Human Biology and Human Genetics, University of Kaiserslautern, 67663, Kaiserslautern, Germany
| | - Edward H Koo
- San Diego (UCSD), Department of Neuroscience, University of California, La Jolla, CA, 92093-0662, USA
| | - Gunnar Brinkmalm
- Department of Psychiatry and Neurochemistry, Institute of Neuroscience and Physiology, The Sahlgrenska Academy at the University of Gothenburg, Mölndal, Sweden
| | - Henrik Zetterberg
- Department of Psychiatry and Neurochemistry, Institute of Neuroscience and Physiology, The Sahlgrenska Academy at the University of Gothenburg, Mölndal, Sweden
- Clinical Neurochemistry Laboratory, Sahlgrenska University Hospital, Mölndal, Sweden
- Department of Neurodegenerative Disease, UCL Institute of Neurology, Queen Square, London, UK
- UK Dementia Research Institute at UCL, London, UK
- Hong Kong Center for Neurodegenerative Diseases, Clear Water Bay, Hong Kong, China
| | - Stefan Kins
- Department of Human Biology and Human Genetics, University of Kaiserslautern, 67663, Kaiserslautern, Germany
| | - Simone Eggert
- Department of Human Biology and Human Genetics, University of Kaiserslautern, 67663, Kaiserslautern, Germany.
- Department of Neurogenetics, Max Planck Institute for Multidisciplinary Sciences, City-Campus, Hermann-Rein-Str. 3, 37075, Göttingen, Germany.
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14
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Munz M, Bharioke A, Kosche G, Moreno-Juan V, Brignall A, Rodrigues TM, Graff-Meyer A, Ulmer T, Haeuselmann S, Pavlinic D, Ledergerber N, Gross-Scherf B, Rózsa B, Krol J, Picelli S, Cowan CS, Roska B. Pyramidal neurons form active, transient, multilayered circuits perturbed by autism-associated mutations at the inception of neocortex. Cell 2023; 186:1930-1949.e31. [PMID: 37071993 PMCID: PMC10156177 DOI: 10.1016/j.cell.2023.03.025] [Citation(s) in RCA: 17] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2022] [Revised: 02/01/2023] [Accepted: 03/22/2023] [Indexed: 04/20/2023]
Abstract
Cortical circuits are composed predominantly of pyramidal-to-pyramidal neuron connections, yet their assembly during embryonic development is not well understood. We show that mouse embryonic Rbp4-Cre cortical neurons, transcriptomically closest to layer 5 pyramidal neurons, display two phases of circuit assembly in vivo. At E14.5, they form a multi-layered circuit motif, composed of only embryonic near-projecting-type neurons. By E17.5, this transitions to a second motif involving all three embryonic types, analogous to the three adult layer 5 types. In vivo patch clamp recordings and two-photon calcium imaging of embryonic Rbp4-Cre neurons reveal active somas and neurites, tetrodotoxin-sensitive voltage-gated conductances, and functional glutamatergic synapses, from E14.5 onwards. Embryonic Rbp4-Cre neurons strongly express autism-associated genes and perturbing these genes interferes with the switch between the two motifs. Hence, pyramidal neurons form active, transient, multi-layered pyramidal-to-pyramidal circuits at the inception of neocortex, and studying these circuits could yield insights into the etiology of autism.
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Affiliation(s)
- Martin Munz
- Institute of Molecular and Clinical Ophthalmology Basel, Basel, Switzerland; Department of Ophthalmology, University of Basel, Basel, Switzerland; Neural Circuit Laboratories, Friedrich Miescher Institute for Biomedical Research, Basel, Switzerland
| | - Arjun Bharioke
- Institute of Molecular and Clinical Ophthalmology Basel, Basel, Switzerland; Department of Ophthalmology, University of Basel, Basel, Switzerland; Neural Circuit Laboratories, Friedrich Miescher Institute for Biomedical Research, Basel, Switzerland
| | - Georg Kosche
- Institute of Molecular and Clinical Ophthalmology Basel, Basel, Switzerland; Department of Ophthalmology, University of Basel, Basel, Switzerland
| | - Verónica Moreno-Juan
- Institute of Molecular and Clinical Ophthalmology Basel, Basel, Switzerland; Department of Ophthalmology, University of Basel, Basel, Switzerland
| | - Alexandra Brignall
- Institute of Molecular and Clinical Ophthalmology Basel, Basel, Switzerland; Department of Ophthalmology, University of Basel, Basel, Switzerland
| | - Tiago M Rodrigues
- Institute of Molecular and Clinical Ophthalmology Basel, Basel, Switzerland; Department of Ophthalmology, University of Basel, Basel, Switzerland
| | - Alexandra Graff-Meyer
- Neural Circuit Laboratories, Friedrich Miescher Institute for Biomedical Research, Basel, Switzerland
| | - Talia Ulmer
- Institute of Molecular and Clinical Ophthalmology Basel, Basel, Switzerland; Department of Ophthalmology, University of Basel, Basel, Switzerland; Neural Circuit Laboratories, Friedrich Miescher Institute for Biomedical Research, Basel, Switzerland
| | - Stephanie Haeuselmann
- Institute of Molecular and Clinical Ophthalmology Basel, Basel, Switzerland; Department of Ophthalmology, University of Basel, Basel, Switzerland
| | - Dinko Pavlinic
- Institute of Molecular and Clinical Ophthalmology Basel, Basel, Switzerland; Department of Ophthalmology, University of Basel, Basel, Switzerland
| | - Nicole Ledergerber
- Institute of Molecular and Clinical Ophthalmology Basel, Basel, Switzerland; Department of Ophthalmology, University of Basel, Basel, Switzerland; Neural Circuit Laboratories, Friedrich Miescher Institute for Biomedical Research, Basel, Switzerland
| | - Brigitte Gross-Scherf
- Institute of Molecular and Clinical Ophthalmology Basel, Basel, Switzerland; Department of Ophthalmology, University of Basel, Basel, Switzerland; Neural Circuit Laboratories, Friedrich Miescher Institute for Biomedical Research, Basel, Switzerland
| | - Balázs Rózsa
- Two-Photon Imaging Center, Institute of Experimental Medicine, Hungarian Academy of Sciences, Budapest, Hungary
| | - Jacek Krol
- Institute of Molecular and Clinical Ophthalmology Basel, Basel, Switzerland; Department of Ophthalmology, University of Basel, Basel, Switzerland; Neural Circuit Laboratories, Friedrich Miescher Institute for Biomedical Research, Basel, Switzerland
| | - Simone Picelli
- Institute of Molecular and Clinical Ophthalmology Basel, Basel, Switzerland; Department of Ophthalmology, University of Basel, Basel, Switzerland
| | - Cameron S Cowan
- Institute of Molecular and Clinical Ophthalmology Basel, Basel, Switzerland; Department of Ophthalmology, University of Basel, Basel, Switzerland
| | - Botond Roska
- Institute of Molecular and Clinical Ophthalmology Basel, Basel, Switzerland; Department of Ophthalmology, University of Basel, Basel, Switzerland.
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15
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Feller B, Fallon A, Luo W, Nguyen PT, Shlaifer I, Lee AK, Chofflet N, Yi N, Khaled H, Karkout S, Bourgault S, Durcan TM, Takahashi H. α-Synuclein Preformed Fibrils Bind to β-Neurexins and Impair β-Neurexin-Mediated Presynaptic Organization. Cells 2023; 12:cells12071083. [PMID: 37048156 PMCID: PMC10093570 DOI: 10.3390/cells12071083] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2023] [Revised: 03/28/2023] [Accepted: 03/31/2023] [Indexed: 04/08/2023] Open
Abstract
Synucleinopathies form a group of neurodegenerative diseases defined by the misfolding and aggregation of α-synuclein (α-syn). Abnormal accumulation and spreading of α-syn aggregates lead to synapse dysfunction and neuronal cell death. Yet, little is known about the synaptic mechanisms underlying the α-syn pathology. Here we identified β-isoforms of neurexins (β-NRXs) as presynaptic organizing proteins that interact with α-syn preformed fibrils (α-syn PFFs), toxic α-syn aggregates, but not α-syn monomers. Our cell surface protein binding assays and surface plasmon resonance assays reveal that α-syn PFFs bind directly to β-NRXs through their N-terminal histidine-rich domain (HRD) at the nanomolar range (KD: ~500 nM monomer equivalent). Furthermore, our artificial synapse formation assays show that α-syn PFFs diminish excitatory and inhibitory presynaptic organization induced by a specific isoform of neuroligin 1 that binds only β-NRXs, but not α-isoforms of neurexins. Thus, our data suggest that α-syn PFFs interact with β-NRXs to inhibit β-NRX-mediated presynaptic organization, providing novel molecular insight into how α-syn PFFs induce synaptic pathology in synucleinopathies such as Parkinson’s disease and dementia with Lewy bodies.
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Affiliation(s)
- Benjamin Feller
- Synapse Development and Plasticity Research Unit, Institut de Recherches Cliniques de Montréal, Montreal, QC H2W 1R7, Canada
- Department of Medicine, Université de Montréal, Montreal, QC H3T 1J4, Canada
| | - Aurélie Fallon
- Synapse Development and Plasticity Research Unit, Institut de Recherches Cliniques de Montréal, Montreal, QC H2W 1R7, Canada
- Department of Medicine, Université de Montréal, Montreal, QC H3T 1J4, Canada
| | - Wen Luo
- The Neuro’s Early Drug Discovery Unit (EDDU), Department of Neurology and Neurosurgery, Montreal Neurological Institute-Hospital, McGill University, Montreal, QC H3A 2B4, Canada
| | - Phuong Trang Nguyen
- Department of Chemistry, Quebec Network for Research on Protein Function, Engineering and Applications, PROTEO, Université du Québec à Montréal, Montreal, QC H3C 3P8, Canada
| | - Irina Shlaifer
- The Neuro’s Early Drug Discovery Unit (EDDU), Department of Neurology and Neurosurgery, Montreal Neurological Institute-Hospital, McGill University, Montreal, QC H3A 2B4, Canada
| | - Alfred Kihoon Lee
- Synapse Development and Plasticity Research Unit, Institut de Recherches Cliniques de Montréal, Montreal, QC H2W 1R7, Canada
- Integrated Program in Neuroscience, McGill University, Montreal, QC H3A 2B2, Canada
| | - Nicolas Chofflet
- Synapse Development and Plasticity Research Unit, Institut de Recherches Cliniques de Montréal, Montreal, QC H2W 1R7, Canada
- Integrated Program in Neuroscience, McGill University, Montreal, QC H3A 2B2, Canada
| | - Nayoung Yi
- Synapse Development and Plasticity Research Unit, Institut de Recherches Cliniques de Montréal, Montreal, QC H2W 1R7, Canada
- Department of Medicine, Université de Montréal, Montreal, QC H3T 1J4, Canada
| | - Husam Khaled
- Synapse Development and Plasticity Research Unit, Institut de Recherches Cliniques de Montréal, Montreal, QC H2W 1R7, Canada
- Department of Medicine, Université de Montréal, Montreal, QC H3T 1J4, Canada
| | - Samer Karkout
- Synapse Development and Plasticity Research Unit, Institut de Recherches Cliniques de Montréal, Montreal, QC H2W 1R7, Canada
| | - Steve Bourgault
- Department of Chemistry, Quebec Network for Research on Protein Function, Engineering and Applications, PROTEO, Université du Québec à Montréal, Montreal, QC H3C 3P8, Canada
| | - Thomas M. Durcan
- The Neuro’s Early Drug Discovery Unit (EDDU), Department of Neurology and Neurosurgery, Montreal Neurological Institute-Hospital, McGill University, Montreal, QC H3A 2B4, Canada
- Integrated Program in Neuroscience, McGill University, Montreal, QC H3A 2B2, Canada
| | - Hideto Takahashi
- Synapse Development and Plasticity Research Unit, Institut de Recherches Cliniques de Montréal, Montreal, QC H2W 1R7, Canada
- Department of Medicine, Université de Montréal, Montreal, QC H3T 1J4, Canada
- Integrated Program in Neuroscience, McGill University, Montreal, QC H3A 2B2, Canada
- Division of Experimental Medicine, McGill University, Montreal, QC H3A 0G4, Canada
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16
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Lee AK, Yi N, Khaled H, Feller B, Takahashi H. SorCS1 inhibits amyloid-β binding to neurexin and rescues amyloid-β-induced synaptic pathology. Life Sci Alliance 2023; 6:e202201681. [PMID: 36697254 PMCID: PMC9880023 DOI: 10.26508/lsa.202201681] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2022] [Revised: 01/13/2023] [Accepted: 01/16/2023] [Indexed: 01/27/2023] Open
Abstract
Amyloid-β oligomers (AβOs), toxic peptide aggregates found in Alzheimer's disease, cause synapse pathology. AβOs interact with neurexins (NRXs), key synaptic organizers, and this interaction dampens normal trafficking and function of NRXs. Axonal trafficking of NRX is in part regulated by its interaction with SorCS1, a protein sorting receptor, but the impact of SorCS1 regulation of NRXs in Aβ pathology was previously unstudied. Here, we show competition between the SorCS1 ectodomain and AβOs for β-NRX binding and rescue effects of the SorCS1b isoform on AβO-induced synaptic pathology. Like AβOs, the SorCS1 ectodomain binds to NRX1β through the histidine-rich domain of NRX1β, and the SorCS1 ectodomain and AβOs compete for NRX1β binding. In cultured hippocampal neurons, SorCS1b colocalizes with NRX1β on the axon surface, and axonal expression of SorCS1b rescues AβO-induced impairment of NRX-mediated presynaptic organization and presynaptic vesicle recycling and AβO-induced structural defects in excitatory synapses. Thus, our data suggest a role for SorCS1 in the rescue of AβO-induced NRX dysfunction and synaptic pathology, providing the basis for a novel potential therapeutic strategy for Alzheimer's disease.
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Affiliation(s)
- Alfred Kihoon Lee
- Synapse Development and Plasticity Research Unit, Institut de Recherches Cliniques de Montréal, Montreal, Canada
- Integrated Program in Neuroscience, McGill University, Montreal, Canada
| | - Nayoung Yi
- Synapse Development and Plasticity Research Unit, Institut de Recherches Cliniques de Montréal, Montreal, Canada
- Department of Medicine, Université de Montréal, Montreal, Canada
| | - Husam Khaled
- Synapse Development and Plasticity Research Unit, Institut de Recherches Cliniques de Montréal, Montreal, Canada
- Department of Medicine, Université de Montréal, Montreal, Canada
| | - Benjamin Feller
- Synapse Development and Plasticity Research Unit, Institut de Recherches Cliniques de Montréal, Montreal, Canada
- Department of Medicine, Université de Montréal, Montreal, Canada
| | - Hideto Takahashi
- Synapse Development and Plasticity Research Unit, Institut de Recherches Cliniques de Montréal, Montreal, Canada
- Integrated Program in Neuroscience, McGill University, Montreal, Canada
- Department of Medicine, Université de Montréal, Montreal, Canada
- Division of Experimental Medicine, McGill University, Montreal, Canada
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17
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Hamid SA, Imayasu M, Yoshida T, Tsutsui H. Epitope-tag-mediated synaptogenic activity in an engineered neurexin-1β lacking the binding interface with neuroligin-1. Biochem Biophys Res Commun 2023; 658:141-147. [PMID: 37030069 DOI: 10.1016/j.bbrc.2023.03.063] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2023] [Revised: 03/18/2023] [Accepted: 03/25/2023] [Indexed: 03/31/2023]
Abstract
Clustering of neurexin-1β occurs through the formation of a trans-cellular complex with neuroligin-1, which promotes the generation of presynapse. While the extracellular region of neurexin-1β functions to constitute the heterophilic binding interface with neuroligin-1, it has remained unclear whether the region could also play any key role in exerting the intracellular signaling for presynaptic differentiation. In this study, we generated neurexin-1β lacking the binding site to neuroligin-1 and with a FLAG epitope at the N-terminus, and examined its activity in cultured neurons. The engineered protein still exhibited robust synaptogenic activities upon the epitope-mediated clustering, indicating that the region for complex formation and that for transmitting presynapse differentiation signals are structurally independent of each other. Using a fluorescence protein as an epitope, synaptogenesis was also induced by a gene-codable nanobody. The finding opens possibilities of neurexin-1β as a platform for developing various molecular tools which may allow, for example, precise modifications of neural wirings under genetic control.
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Affiliation(s)
- Sm Ahasanul Hamid
- School of Materials Science, Japan Advanced Institute of Science and Technology, Nomi, Ishikawa, 923-1292, Japan
| | - Mieko Imayasu
- School of Materials Science, Japan Advanced Institute of Science and Technology, Nomi, Ishikawa, 923-1292, Japan
| | - Tomoyuki Yoshida
- Department of Molecular Neuroscience, Faculty of Medicine, University of Toyama, Toyama, 930-0194, Japan; Research Center for Idling Brain Science, University of Toyama, Toyama, 930-0194, Japan
| | - Hidekazu Tsutsui
- School of Materials Science, Japan Advanced Institute of Science and Technology, Nomi, Ishikawa, 923-1292, Japan.
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18
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Traunmüller L, Schulz J, Ortiz R, Feng H, Furlanis E, Gomez AM, Schreiner D, Bischofberger J, Zhang C, Scheiffele P. A cell-type-specific alternative splicing regulator shapes synapse properties in a trans-synaptic manner. Cell Rep 2023; 42:112173. [PMID: 36862556 PMCID: PMC10066595 DOI: 10.1016/j.celrep.2023.112173] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2022] [Revised: 12/07/2022] [Accepted: 02/12/2023] [Indexed: 03/03/2023] Open
Abstract
The specification of synaptic properties is fundamental for the function of neuronal circuits. "Terminal selector" transcription factors coordinate terminal gene batteries that specify cell-type-specific properties. Moreover, pan-neuronal splicing regulators have been implicated in directing neuronal differentiation. However, the cellular logic of how splicing regulators instruct specific synaptic properties remains poorly understood. Here, we combine genome-wide mapping of mRNA targets and cell-type-specific loss-of-function studies to uncover the contribution of the RNA-binding protein SLM2 to hippocampal synapse specification. Focusing on pyramidal cells and somatostatin (SST)-positive GABAergic interneurons, we find that SLM2 preferentially binds and regulates alternative splicing of transcripts encoding synaptic proteins. In the absence of SLM2, neuronal populations exhibit normal intrinsic properties, but there are non-cell-autonomous synaptic phenotypes and associated defects in a hippocampus-dependent memory task. Thus, alternative splicing provides a critical layer of gene regulation that instructs specification of neuronal connectivity in a trans-synaptic manner.
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Affiliation(s)
| | - Jan Schulz
- Department of Biomedicine, University of Basel, 4056 Basel, Switzerland
| | - Raul Ortiz
- Biozentrum of the University of Basel, 4056 Basel, Switzerland
| | - Huijuan Feng
- Department of Systems Biology, Department of Biochemistry and Molecular Biophysics, Center for Motor Neuron Biology and Disease, Columbia University, New York, NY 10032, USA
| | | | - Andrea M Gomez
- Biozentrum of the University of Basel, 4056 Basel, Switzerland
| | | | | | - Chaolin Zhang
- Department of Systems Biology, Department of Biochemistry and Molecular Biophysics, Center for Motor Neuron Biology and Disease, Columbia University, New York, NY 10032, USA
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19
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Extracellular matrix and synapse formation. Biosci Rep 2023; 43:232259. [PMID: 36503961 PMCID: PMC9829651 DOI: 10.1042/bsr20212411] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2022] [Revised: 11/08/2022] [Accepted: 11/24/2022] [Indexed: 12/14/2022] Open
Abstract
The extracellular matrix (ECM) is a complex molecular network distributed throughout the extracellular space of different tissues as well as the neuronal system. Previous studies have identified various ECM components that play important roles in neuronal maturation and signal transduction. ECM components are reported to be involved in neurogenesis, neuronal migration, and axonal growth by interacting or binding to specific receptors. In addition, the ECM is found to regulate synapse formation, the stability of the synaptic structure, and synaptic plasticity. Here, we mainly reviewed the effects of various ECM components on synapse formation and briefly described the related diseases caused by the abnormality of several ECM components.
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20
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Synaptic Development in Diverse Olfactory Neuron Classes Uses Distinct Temporal and Activity-Related Programs. J Neurosci 2023; 43:28-55. [PMID: 36446587 PMCID: PMC9838713 DOI: 10.1523/jneurosci.0884-22.2022] [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: 05/12/2022] [Revised: 10/18/2022] [Accepted: 11/02/2022] [Indexed: 12/03/2022] Open
Abstract
Developing neurons must meet core molecular, cellular, and temporal requirements to ensure the correct formation of synapses, resulting in functional circuits. However, because of the vast diversity in neuronal class and function, it is unclear whether or not all neurons use the same organizational mechanisms to form synaptic connections and achieve functional and morphologic maturation. Moreover, it remains unknown whether neurons united in a common goal and comprising the same sensory circuit develop on similar timescales and use identical molecular approaches to ensure the formation of the correct number of synapses. To begin to answer these questions, we took advantage of the Drosophila antennal lobe (AL), a model olfactory circuit with remarkable genetic access and synapse-level resolution. Using tissue-specific genetic labeling of active zones, we performed a quantitative analysis of synapse formation in multiple classes of neurons of both sexes throughout development and adulthood. We found that olfactory receptor neurons (ORNs), projection neurons (PNs), and local interneurons (LNs) each have unique time courses of synaptic development, addition, and refinement, demonstrating that each class follows a distinct developmental program. This raised the possibility that these classes may also have distinct molecular requirements for synapse formation. We genetically altered neuronal activity in each neuronal subtype and observed differing effects on synapse number based on the neuronal class examined. Silencing neuronal activity in ORNs, PNs, and LNs impaired synaptic development but only in ORNs did enhancing neuronal activity influence synapse formation. ORNs and LNs demonstrated similar impairment of synaptic development with enhanced activity of a master kinase, GSK-3β, suggesting that neuronal activity and GSK-3β kinase activity function in a common pathway. ORNs also, however, demonstrated impaired synaptic development with GSK-3β loss-of-function, suggesting additional activity-independent roles in development. Ultimately, our results suggest that the requirements for synaptic development are not uniform across all neuronal classes with considerable diversity existing in both their developmental time frames and molecular requirements. These findings provide novel insights into the mechanisms of synaptic development and lay the foundation for future work determining their underlying etiologies.SIGNIFICANCE STATEMENT Distinct olfactory neuron classes in Drosophila develop a mature synaptic complement over unique timelines and using distinct activity-dependent and molecular programs, despite having the same generalized goal of olfactory sensation.
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21
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Dai J, Liakath-Ali K, Golf SR, Südhof TC. Distinct neurexin-cerebellin complexes control AMPA- and NMDA-receptor responses in a circuit-dependent manner. eLife 2022; 11:e78649. [PMID: 36205393 PMCID: PMC9586558 DOI: 10.7554/elife.78649] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2022] [Accepted: 10/06/2022] [Indexed: 01/11/2023] Open
Abstract
At CA1→subiculum synapses, alternatively spliced neurexin-1 (Nrxn1SS4+) and neurexin-3 (Nrxn3SS4+) enhance NMDA-receptors and suppress AMPA-receptors, respectively, without affecting synapse formation. Nrxn1SS4+ and Nrxn3SS4+ act by binding to secreted cerebellin-2 (Cbln2) that in turn activates postsynaptic GluD1 receptors. Whether neurexin-Cbln2-GluD1 signaling has additional functions besides regulating NMDA- and AMPA-receptors, and whether such signaling performs similar roles at other synapses, however, remains unknown. Here, we demonstrate using constitutive Cbln2 deletions in mice that at CA1→subiculum synapses, Cbln2 performs no additional developmental roles besides regulating AMPA- and NMDA-receptors. Moreover, low-level expression of functionally redundant Cbln1 did not compensate for a possible synapse-formation function of Cbln2 at CA1→subiculum synapses. In exploring the generality of these findings, we examined the prefrontal cortex where Cbln2 was recently implicated in spinogenesis, and the cerebellum where Cbln1 is known to regulate parallel-fiber synapses. In the prefrontal cortex, Nrxn1SS4+-Cbln2 signaling selectively controlled NMDA-receptors without affecting spine or synapse numbers, whereas Nrxn3SS4+-Cbln2 signaling had no apparent role. In the cerebellum, conversely, Nrxn3SS4+-Cbln1 signaling regulated AMPA-receptors, whereas now Nrxn1SS4+-Cbln1 signaling had no manifest effect. Thus, Nrxn1SS4+- and Nrxn3SS4+-Cbln1/2 signaling complexes differentially control NMDA- and AMPA-receptors in different synapses in diverse neural circuits without regulating synapse or spine formation.
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Affiliation(s)
- Jinye Dai
- Howard Hughes Medical Institute, Stanford UniversityStanfordUnited States
- Department of Molecular and Cellular Physiology, Stanford UniversityStanfordUnited States
| | - Kif Liakath-Ali
- Department of Molecular and Cellular Physiology, Stanford UniversityStanfordUnited States
| | - Samantha Rose Golf
- Department of Molecular and Cellular Physiology, Stanford UniversityStanfordUnited States
| | - Thomas C Südhof
- Howard Hughes Medical Institute, Stanford UniversityStanfordUnited States
- Department of Molecular and Cellular Physiology, Stanford UniversityStanfordUnited States
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22
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Investigating the Role of GABA in Neural Development and Disease Using Mice Lacking GAD67 or VGAT Genes. Int J Mol Sci 2022; 23:ijms23147965. [PMID: 35887307 PMCID: PMC9318753 DOI: 10.3390/ijms23147965] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2022] [Revised: 07/12/2022] [Accepted: 07/16/2022] [Indexed: 11/18/2022] Open
Abstract
Normal development and function of the central nervous system involves a balance between excitatory and inhibitory neurotransmission. Activity of both excitatory and inhibitory neurons is modulated by inhibitory signalling of the GABAergic and glycinergic systems. Mechanisms that regulate formation, maturation, refinement, and maintenance of inhibitory synapses are established in early life. Deviations from ideal excitatory and inhibitory balance, such as down-regulated inhibition, are linked with many neurological diseases, including epilepsy, schizophrenia, anxiety, and autism spectrum disorders. In the mammalian forebrain, GABA is the primary inhibitory neurotransmitter, binding to GABA receptors, opening chloride channels and hyperpolarizing the cell. We review the involvement of down-regulated inhibitory signalling in neurological disorders, possible mechanisms for disease progression, and targets for therapeutic intervention. We conclude that transgenic models of disrupted inhibitory signalling—in GAD67+/− and VGAT−/− mice—are useful for investigating the effects of down-regulated inhibitory signalling in a range of neurological diseases.
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23
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Oku S, Siddiqui TJ. A GPI-anchored Neurexin 3 proteoform mediates dendritic inhibition. Neuron 2022; 110:2041-2044. [DOI: 10.1016/j.neuron.2022.06.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
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24
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Saint‐Martin M, Goda Y. Astrocyte–synapse interactions and cell adhesion molecules. FEBS J 2022. [DOI: 10.1111/febs.16540] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2022] [Revised: 05/20/2022] [Accepted: 05/31/2022] [Indexed: 12/22/2022]
Affiliation(s)
- Margaux Saint‐Martin
- Laboratory for Synaptic Plasticity and Connectivity RIKEN Center for Brain Science Wako‐shi, Saitama Japan
| | - Yukiko Goda
- Laboratory for Synaptic Plasticity and Connectivity RIKEN Center for Brain Science Wako‐shi, Saitama Japan
- Synapse Biology Unit Okinawa Institute of Science and Technology Graduate University Japan
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25
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Li N, Chen S, Xu NJ, Sun S, Chen JJ, Liu XD. Scaffold Protein Lnx1 Stabilizes EphB Receptor Kinases for Synaptogenesis. Front Mol Neurosci 2022; 15:861873. [PMID: 35531068 PMCID: PMC9070102 DOI: 10.3389/fnmol.2022.861873] [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: 01/25/2022] [Accepted: 03/04/2022] [Indexed: 12/04/2022] Open
Abstract
Postsynaptic structure assembly and remodeling are crucial for functional synapse formation during the establishment of neural circuits. However, how the specific scaffold proteins regulate this process during the development of the postnatal period is poorly understood. In this study, we find that the deficiency of ligand of Numb protein X 1 (Lnx1) leads to abnormal development of dendritic spines to impair functional synaptic formation. We further demonstrate that loss of Lnx1 promotes the internalization of EphB receptors from the cell surface. Constitutively active EphB2 intracellular signaling rescues synaptogenesis in Lnx1 mutant mice. Our data thus reveal a molecular mechanism whereby the Lnx1-EphB complex controls postsynaptic structure for synapse maturation during the adolescent period.
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Affiliation(s)
- Na Li
- Research Center of Translational Medicine, Shanghai Children's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China.,Department of Anatomy and Physiology, Shanghai Jiao Tong University School of Medicine, Shanghai, China.,Shanghai Collaborative Innovation Center for Translational Medicine, Shanghai Jiao Tong University School of Medicine, Shanghai, China.,Shanghai Key Laboratory of Reproductive Medicine, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Si Chen
- Research Center of Translational Medicine, Shanghai Children's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China.,Department of Anatomy and Physiology, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Nan-Jie Xu
- Research Center of Translational Medicine, Shanghai Children's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China.,Department of Anatomy and Physiology, Shanghai Jiao Tong University School of Medicine, Shanghai, China.,Shanghai Key Laboratory of Reproductive Medicine, Shanghai Jiao Tong University School of Medicine, Shanghai, China.,Key Laboratory of Cell Differentiation and Apoptosis of Chinese Ministry of Education, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Suya Sun
- Department of Neurology and Institute of Neurology, Rui Jin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Jin-Jin Chen
- Research Center of Translational Medicine, Shanghai Children's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China.,Department of Anatomy and Physiology, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Xian-Dong Liu
- Department of Neurology and Institute of Neurology, Rui Jin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
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26
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Hauser D, Behr K, Konno K, Schreiner D, Schmidt A, Watanabe M, Bischofberger J, Scheiffele P. Targeted proteoform mapping uncovers specific Neurexin-3 variants required for dendritic inhibition. Neuron 2022; 110:2094-2109.e10. [PMID: 35550065 PMCID: PMC9275415 DOI: 10.1016/j.neuron.2022.04.017] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2021] [Revised: 02/05/2022] [Accepted: 04/15/2022] [Indexed: 12/21/2022]
Abstract
The diversification of cell adhesion molecules by alternative splicing is proposed to underlie molecular codes for neuronal wiring. Transcriptomic approaches mapped detailed cell-type-specific mRNA splicing programs. However, it has been hard to probe the synapse-specific localization and function of the resulting protein splice isoforms, or “proteoforms,” in vivo. We here apply a proteoform-centric workflow in mice to test the synapse-specific functions of the splice isoforms of the synaptic adhesion molecule Neurexin-3 (NRXN3). We uncover a major proteoform, NRXN3 AS5, that is highly expressed in GABAergic interneurons and at dendrite-targeting GABAergic terminals. NRXN3 AS5 abundance significantly diverges from Nrxn3 mRNA distribution and is gated by translation-repressive elements. Nrxn3 AS5 isoform deletion results in a selective impairment of dendrite-targeting interneuron synapses in the dentate gyrus without affecting somatic inhibition or glutamatergic perforant-path synapses. This work establishes cell- and synapse-specific functions of a specific neurexin proteoform and highlights the importance of alternative splicing regulation for synapse specification. Translational regulation guides alternative Neurexin proteoform expression NRXN3 AS5 proteoforms are concentrated at dendrite-targeting interneuron synapses A proteome-centric workflow uncovers NRXN3 AS5 interactors in vivo Loss of NRXN3 AS5 leads to selective impairments in dendritic inhibition
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Affiliation(s)
- David Hauser
- Biozentrum of the University of Basel, Spitalstrasse 41, 4056 Basel, Switzerland
| | - Katharina Behr
- Department of Biomedicine, University of Basel, Pestalozzistrasse 20, 4056 Basel, Switzerland
| | - Kohtarou Konno
- Department of Anatomy, Faculty of Medicine, Hokkaido University, Sapporo, Japan
| | - Dietmar Schreiner
- Biozentrum of the University of Basel, Spitalstrasse 41, 4056 Basel, Switzerland
| | - Alexander Schmidt
- Biozentrum of the University of Basel, Spitalstrasse 41, 4056 Basel, Switzerland
| | - Masahiko Watanabe
- Department of Anatomy, Faculty of Medicine, Hokkaido University, Sapporo, Japan
| | - Josef Bischofberger
- Department of Biomedicine, University of Basel, Pestalozzistrasse 20, 4056 Basel, Switzerland
| | - Peter Scheiffele
- Biozentrum of the University of Basel, Spitalstrasse 41, 4056 Basel, Switzerland.
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27
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Teng Z, Gottmann K. Hemisynapse Formation Between Target Astrocytes and Cortical Neuron Axons in vitro. Front Mol Neurosci 2022; 15:829506. [PMID: 35386271 PMCID: PMC8978633 DOI: 10.3389/fnmol.2022.829506] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2021] [Accepted: 02/08/2022] [Indexed: 01/28/2023] Open
Abstract
One of the most fundamental organizing principles in the mammalian brain is that neurons do not establish synapses with the other major cell type, the astrocytes. However, induced synapse formation between neurons and astrocytes appears conceivable, because astrocytes are well known to express functional ionotropic glutamate receptors. Here, we attempted to trigger synapse formation between co-cultured neurons and astrocytes by overexpressing the strongly synaptogenic adhesion protein LRRTM2 in astrocytes physically contacted by cortical axons. Interestingly, control experiments with immature cortical astrocytes without any overexpression resulted in the induction of synaptic vesicle clustering in contacting axons (hemisynapse formation). This synaptogenic activity correlated with the endogenous expression of the synaptogenic protein Neuroligin1. Hemisynapse formation was further enhanced upon overexpression of LRRTM2 in cortical astrocytes. In contrast, cerebellar astrocytes required overexpression of LRRTM2 for induction of synaptic vesicle clustering in contacting axons. We further addressed, whether hemisynapse formation was accompanied by the appearance of fully functional glutamatergic synapses. We therefore attempted to record AMPA receptor-mediated miniature excitatory postsynaptic currents (mEPSCs) in innervated astrocytes using the whole-cell patch-clamp technique. Despite the endogenous expression of the AMPA receptor subunits GluA2 and to a lesser extent GluA1, we did not reliably observe spontaneous AMPA mEPSCs. In conclusion, overexpression of the synaptogenic protein LRRTM2 induced hemisynapse formation between co-cultured neurons and astrocytes. However, the formation of fully functional synapses appeared to require additional factors critical for nano-alignment of presynaptic vesicles and postsynaptic receptors.
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28
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Wang CY, Trotter JH, Liakath-Ali K, Lee SJ, Liu X, Südhof TC. Molecular self-avoidance in synaptic neurexin complexes. SCIENCE ADVANCES 2021; 7:eabk1924. [PMID: 34919427 PMCID: PMC8682996 DOI: 10.1126/sciadv.abk1924] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/28/2021] [Accepted: 11/01/2021] [Indexed: 05/30/2023]
Abstract
Synapses are thought to be organized by interactions of presynaptic neurexins with postsynaptic ligands, particularly with neuroligins and cerebellins. However, when a neuron forms adjacent pre- and postsynaptic specializations, as in dendrodendritic or axo-axonic synapses, nonfunctional cis neurexin/ligand interactions would be energetically favored. Here, we reveal an organizational principle for preventing synaptic cis interactions (“self-avoidance”). Using dendrodendritic synapses between mitral and granule cells in the olfactory bulb as a paradigm, we show that, owing to its higher binding affinity, cerebellin-1 blocks the cis interaction of neurexins with neuroligins, thereby enabling trans neurexin/neuroligin interaction. In mitral cells, ablating either cerebellin-1 or neuroligins severely impaired granule cell➔mitral cell synapses, as did overexpression of wild-type neurexins but not of mutant neurexins unable to bind to neuroligins. Our data uncover a molecular interaction network that organizes the self-avoidance of nonfunctional neurexin/ligand cis interactions, thus allowing assembly of physiological trans interactions.
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Affiliation(s)
- Cosmos Yuqi Wang
- Department of Molecular and Cellular Physiology, School of Medicine, Stanford University, Stanford, CA 94305, USA
| | - Justin H. Trotter
- Department of Molecular and Cellular Physiology, School of Medicine, Stanford University, Stanford, CA 94305, USA
| | - Kif Liakath-Ali
- Department of Molecular and Cellular Physiology, School of Medicine, Stanford University, Stanford, CA 94305, USA
| | - Sung-Jin Lee
- Department of Molecular and Cellular Physiology, School of Medicine, Stanford University, Stanford, CA 94305, USA
| | - Xinran Liu
- Department of Cell Biology, School of Medicine, Yale University, New Haven, CT 06510, USA
| | - Thomas C. Südhof
- Department of Molecular and Cellular Physiology, School of Medicine, Stanford University, Stanford, CA 94305, USA
- Howard Hughes Medical Institute, School of Medicine, Stanford University, Stanford, CA 94305, USA
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29
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Schizophrenia-associated LRRTM1 regulates cognitive behavior through controlling synaptic function in the mediodorsal thalamus. Mol Psychiatry 2021; 26:6912-6925. [PMID: 33981006 DOI: 10.1038/s41380-021-01146-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/07/2020] [Revised: 04/16/2021] [Accepted: 04/22/2021] [Indexed: 01/08/2023]
Abstract
Reduced activity of the mediodorsal thalamus (MD) and abnormal functional connectivity of the MD with the prefrontal cortex (PFC) cause cognitive deficits in schizophrenia. However, the molecular basis of MD hypofunction in schizophrenia is not known. Here, we identified leucine-rich-repeat transmembrane neuronal protein 1 (LRRTM1), a postsynaptic cell-adhesion molecule, as a key regulator of excitatory synaptic function and excitation-inhibition balance in the MD. LRRTM1 is strongly associated with schizophrenia and is highly expressed in the thalamus. Conditional deletion of Lrrtm1 in the MD in adult mice reduced excitatory synaptic function and caused a parallel reduction in the afferent synaptic activity of the PFC, which was reversed by the reintroduction of LRRTM1 in the MD. Our results indicate that chronic reduction of synaptic strength in the MD by targeted deletion of Lrrtm1 functionally disengages the MD from the PFC and may account for cognitive, social, and sensorimotor gating deficits, reminiscent of schizophrenia.
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30
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Lie E, Yeo Y, Lee EJ, Shin W, Kim K, Han KA, Yang E, Choi TY, Bae M, Lee S, Um SM, Choi SY, Kim H, Ko J, Kim E. SALM4 negatively regulates NMDA receptor function and fear memory consolidation. Commun Biol 2021; 4:1138. [PMID: 34588597 PMCID: PMC8481232 DOI: 10.1038/s42003-021-02656-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2020] [Accepted: 09/09/2021] [Indexed: 02/08/2023] Open
Abstract
Many synaptic adhesion molecules positively regulate synapse development and function, but relatively little is known about negative regulation. SALM4/Lrfn3 (synaptic adhesion-like molecule 4/leucine rich repeat and fibronectin type III domain containing 3) inhibits synapse development by suppressing other SALM family proteins, but whether SALM4 also inhibits synaptic function and specific behaviors remains unclear. Here we show that SALM4-knockout (Lrfn3-/-) male mice display enhanced contextual fear memory consolidation (7-day post-training) but not acquisition or 1-day retention, and exhibit normal cued fear, spatial, and object-recognition memory. The Lrfn3-/- hippocampus show increased currents of GluN2B-containing N-methyl-D-aspartate (NMDA) receptors (GluN2B-NMDARs), but not α-amino-3-hydroxy-5-methyl-4-isoxazole propionate (AMPA) receptors (AMPARs), which requires the presynaptic receptor tyrosine phosphatase PTPσ. Chronic treatment of Lrfn3-/- mice with fluoxetine, a selective serotonin reuptake inhibitor used to treat excessive fear memory that directly inhibits GluN2B-NMDARs, normalizes NMDAR function and contextual fear memory consolidation in Lrfn3-/- mice, although the GluN2B-specific NMDAR antagonist ifenprodil was not sufficient to reverse the enhanced fear memory consolidation. These results suggest that SALM4 suppresses excessive GluN2B-NMDAR (not AMPAR) function and fear memory consolidation (not acquisition).
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Affiliation(s)
- Eunkyung Lie
- grid.410720.00000 0004 1784 4496Center for Synaptic Brain Dysfunctions, Institute for Basic Science (IBS), Daejeon, 34141 Korea ,grid.255168.d0000 0001 0671 5021Department of Chemistry, Dongguk University, Seoul, 04620 Korea
| | - Yeji Yeo
- grid.37172.300000 0001 2292 0500Department of Biological Sciences, Korea Advanced Institute for Science and Technology (KAIST), Daejeon, 34141 Korea
| | - Eun-Jae Lee
- grid.267370.70000 0004 0533 4667Department of Neurology, Asan Medical Center, University of Ulsan, College of Medicine, Seoul, 05505 Korea
| | - Wangyong Shin
- grid.410720.00000 0004 1784 4496Center for Synaptic Brain Dysfunctions, Institute for Basic Science (IBS), Daejeon, 34141 Korea
| | - Kyungdeok Kim
- grid.410720.00000 0004 1784 4496Center for Synaptic Brain Dysfunctions, Institute for Basic Science (IBS), Daejeon, 34141 Korea
| | - Kyung Ah Han
- grid.417736.00000 0004 0438 6721Department of Brain and Cognitive Sciences, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Hyeonpoong-Eup, Dalseong-Gun, Daegu, 42988 Korea
| | - Esther Yang
- grid.222754.40000 0001 0840 2678Department of Anatomy and Division of Brain Korea 21, Biomedical Science, College of Medicine, Korea University, Seoul, 02841 Korea
| | - Tae-Yong Choi
- grid.31501.360000 0004 0470 5905Department of Physiology and Neuroscience, Dental Research Institute, Seoul National University School of Dentistry, Seoul, 03080 Korea
| | - Mihyun Bae
- grid.410720.00000 0004 1784 4496Center for Synaptic Brain Dysfunctions, Institute for Basic Science (IBS), Daejeon, 34141 Korea
| | - Suho Lee
- grid.410720.00000 0004 1784 4496Center for Synaptic Brain Dysfunctions, Institute for Basic Science (IBS), Daejeon, 34141 Korea
| | - Seung Min Um
- grid.37172.300000 0001 2292 0500Department of Biological Sciences, Korea Advanced Institute for Science and Technology (KAIST), Daejeon, 34141 Korea
| | - Se-Young Choi
- grid.31501.360000 0004 0470 5905Department of Physiology and Neuroscience, Dental Research Institute, Seoul National University School of Dentistry, Seoul, 03080 Korea
| | - Hyun Kim
- grid.222754.40000 0001 0840 2678Department of Anatomy and Division of Brain Korea 21, Biomedical Science, College of Medicine, Korea University, Seoul, 02841 Korea
| | - Jaewon Ko
- grid.417736.00000 0004 0438 6721Department of Brain and Cognitive Sciences, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Hyeonpoong-Eup, Dalseong-Gun, Daegu, 42988 Korea
| | - Eunjoon Kim
- grid.410720.00000 0004 1784 4496Center for Synaptic Brain Dysfunctions, Institute for Basic Science (IBS), Daejeon, 34141 Korea ,grid.267370.70000 0004 0533 4667Department of Neurology, Asan Medical Center, University of Ulsan, College of Medicine, Seoul, 05505 Korea
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31
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Drulis-Fajdasz D, Gostomska-Pampuch K, Duda P, Wiśniewski JR, Rakus D. Quantitative Proteomics Reveals Significant Differences between Mouse Brain Formations in Expression of Proteins Involved in Neuronal Plasticity during Aging. Cells 2021; 10:2021. [PMID: 34440790 PMCID: PMC8393337 DOI: 10.3390/cells10082021] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2021] [Revised: 07/30/2021] [Accepted: 08/05/2021] [Indexed: 12/22/2022] Open
Abstract
Aging is associated with a general decline in cognitive functions, which appears to be due to alterations in the amounts of proteins involved in the regulation of synaptic plasticity. Here, we present a quantitative analysis of proteins involved in neurotransmission in three brain regions, namely, the hippocampus, the cerebral cortex and the cerebellum, in mice aged 1 and 22 months, using the total protein approach technique. We demonstrate that although the titer of some proteins involved in neurotransmission and synaptic plasticity is affected by aging in a similar manner in all the studied brain formations, in fact, each of the formations represents its own mode of aging. Generally, the hippocampal and cortical proteomes are much more unstable during the lifetime than the cerebellar proteome. The data presented here provide a general picture of the effect of physiological aging on synaptic plasticity and might suggest potential drug targets for anti-aging therapies.
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Affiliation(s)
- Dominika Drulis-Fajdasz
- Department of Molecular Physiology and Neurobiology, University of Wrocław, Sienkiewicza 21, 50-335 Wrocław, Poland; (D.D.-F.); (P.D.)
| | - Kinga Gostomska-Pampuch
- Biochemical Proteomics Group, Department of Proteomics and Signal Transduction, Max Planck Institute of Biochemistry, 82152 Martinsried, Germany; (K.G.-P.); (J.R.W.)
- Department of Biochemistry and Immunochemistry, Wrocław Medical University, Chałubińskiego 10, 50-368 Wrocław, Poland
| | - Przemysław Duda
- Department of Molecular Physiology and Neurobiology, University of Wrocław, Sienkiewicza 21, 50-335 Wrocław, Poland; (D.D.-F.); (P.D.)
| | - Jacek Roman Wiśniewski
- Biochemical Proteomics Group, Department of Proteomics and Signal Transduction, Max Planck Institute of Biochemistry, 82152 Martinsried, Germany; (K.G.-P.); (J.R.W.)
| | - Dariusz Rakus
- Department of Molecular Physiology and Neurobiology, University of Wrocław, Sienkiewicza 21, 50-335 Wrocław, Poland; (D.D.-F.); (P.D.)
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Kamimura K. Roles of Glypican and Heparan Sulfate at the Synapses. TRENDS GLYCOSCI GLYC 2021. [DOI: 10.4052/tigg.2017.1e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Affiliation(s)
- Keisuke Kamimura
- Department of Brain and Neurosciences, Tokyo Metropolitan Institute of Medical Science
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33
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Kamimura K. Roles of Glypican and Heparan Sulfate at the Synapses. TRENDS GLYCOSCI GLYC 2021. [DOI: 10.4052/tigg.2017.1j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Affiliation(s)
- Keisuke Kamimura
- Department of Brain and Neurosciences, Tokyo Metropolitan Institute of Medical Science
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Abstract
This study presents evidence that the MAGUK family of synaptic scaffolding proteins plays an essential, but redundant, role in long-term potentiation (LTP). The action of PSD-95, but not that of SAP102, requires the binding to the transsynaptic adhesion protein ADAM22, which is required for nanocolumn stabilization. Based on these and previous results, we propose a two-step process in the recruitment of AMPARs during LTP. First, AMPARs, via TARPs, bind to exposed PSD-95 in the PSD. This alone is not adequate to enhance synaptic transmission. Second, the AMPAR/TARP/PSD-95 complex is stabilized in the nanocolumn by binding to ADAM22. A second, ADAM22-independent pathway is proposed for SAP102.
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Luo B, Liu Z, Lin D, Chen W, Ren D, Yu Z, Xiong M, Zhao C, Fei E, Li B. ErbB4 promotes inhibitory synapse formation by cell adhesion, independent of its kinase activity. Transl Psychiatry 2021; 11:361. [PMID: 34226493 PMCID: PMC8257755 DOI: 10.1038/s41398-021-01485-6] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/16/2020] [Revised: 06/04/2021] [Accepted: 06/10/2021] [Indexed: 12/12/2022] Open
Abstract
The precise control of the nervous system function under the vitality of synapses is extremely critical. Efforts have been taken to explore the underlying cellular and molecular mechanisms for synapse formation. Cell adhesion molecules have been found important for synapse assembly in the brain. Many trans-adhesion complexes have been identified to modulate excitatory synapse formation. However, little is known about the synaptogenic mechanisms for inhibitory synapses. ErbB4 is a receptor tyrosine kinase enriched in interneurons. Here, we showed that overexpressing ErbB4 in HEK293T cells induced gephyrin or GABAAR α1 puncta in co-cultured primary hippocampal neurons. This induction of ErbB4 was independent of its kinase activity. K751M, a kinase-dead mutant of ErbB4, can also induce gephyrin or GABAAR α1 puncta in the co-culture system. We further constructed K751M knock-in mice and found that the homozygous were viable at birth and fertile without changes in gross brain structure. The number of interneurons and inhibitory synapses onto pyramidal neurons (PyNs) were comparable between K751M and wild-type mice but decreased in ErbB4-Null mice. Moreover, ErbB4 can interact in trans with Slitrk3, a transmembrane postsynaptic protein at inhibitory synapses, through the extracellular RLD domain of ErbB4. The deletion of RLD diminished the induction of gephyrin or GABAAR α1 puncta by ErbB4. Finally, disruption of ErbB4-Slitrk3 interaction through neutralization of Slitrk3 by secretable RLD decreased inhibitory synapses onto PyNs and impaired GABAergic transmission. These results identify that ErbB4, as a cell adhesion molecule, promotes inhibitory synapse formation onto PyNs by interacting with Slitrk3 and in a kinase-independent manner, providing an unexpected mechanism of ErbB4 in inhibitory synapse formation.
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Affiliation(s)
- Bin Luo
- grid.260463.50000 0001 2182 8825School of Life Sciences, Nanchang University, Nanchang, China ,grid.260463.50000 0001 2182 8825Institute of Life Science, Nanchang University, Nanchang, China
| | - Ziyang Liu
- grid.260463.50000 0001 2182 8825School of Life Sciences, Nanchang University, Nanchang, China ,grid.260463.50000 0001 2182 8825Institute of Life Science, Nanchang University, Nanchang, China
| | - Dong Lin
- grid.260463.50000 0001 2182 8825School of Life Sciences, Nanchang University, Nanchang, China ,grid.260463.50000 0001 2182 8825Institute of Life Science, Nanchang University, Nanchang, China
| | - Wenbing Chen
- grid.260463.50000 0001 2182 8825School of Life Sciences, Nanchang University, Nanchang, China ,grid.260463.50000 0001 2182 8825Institute of Life Science, Nanchang University, Nanchang, China
| | - Dongyan Ren
- grid.260463.50000 0001 2182 8825School of Life Sciences, Nanchang University, Nanchang, China ,grid.260463.50000 0001 2182 8825Institute of Life Science, Nanchang University, Nanchang, China
| | - Zheng Yu
- grid.260463.50000 0001 2182 8825Institute of Life Science, Nanchang University, Nanchang, China
| | - Mingtao Xiong
- grid.260463.50000 0001 2182 8825School of Life Sciences, Nanchang University, Nanchang, China ,grid.260463.50000 0001 2182 8825Institute of Life Science, Nanchang University, Nanchang, China
| | - Changqin Zhao
- grid.260463.50000 0001 2182 8825School of Life Sciences, Nanchang University, Nanchang, China ,grid.260463.50000 0001 2182 8825Institute of Life Science, Nanchang University, Nanchang, China
| | - Erkang Fei
- School of Life Sciences, Nanchang University, Nanchang, China. .,Institute of Life Science, Nanchang University, Nanchang, China.
| | - Baoming Li
- School of Life Sciences, Nanchang University, Nanchang, China. .,Institute of Life Science, Nanchang University, Nanchang, China. .,Department of Psychology and Institute of Brain Science, School of Education, Hangzhou Normal University, Hangzhou, China.
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36
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Pan X, Zhou Y, Hotulainen P, Meunier FA, Wang T. The axonal radial contractility: Structural basis underlying a new form of neural plasticity. Bioessays 2021; 43:e2100033. [PMID: 34145916 DOI: 10.1002/bies.202100033] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2021] [Revised: 05/27/2021] [Accepted: 06/02/2021] [Indexed: 12/25/2022]
Abstract
Axons are the longest cellular structure reaching over a meter in the case of human motor axons. They have a relatively small diameter and contain several cytoskeletal elements that mediate both material and information exchange within neurons. Recently, a novel type of axonal plasticity, termed axonal radial contractility, has been unveiled. It is represented by dynamic and transient diameter changes of the axon shaft to accommodate the passages of large organelles. Mechanisms underpinning this plasticity are not fully understood. Here, we first summarised recent evidence of the functional relevance for axon radial contractility, then discussed the underlying structural basis, reviewing nanoscopic evidence of the subtle changes. Two models are proposed to explain how actomyosin rings are organised. Possible roles of non-muscle myosin II (NM-II) in axon degeneration are discussed. Finally, we discuss the concept of periodic functional nanodomains, which could sense extracellular cues and coordinate the axonal responses. Also see the video abstract here: https://youtu.be/ojCnrJ8RCRc.
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Affiliation(s)
- Xiaorong Pan
- Center for Brain Science, School of Life Science and Technology, Shanghaitech University, Shanghai, China
| | - Yimin Zhou
- Center for Brain Science, School of Life Science and Technology, Shanghaitech University, Shanghai, China
| | - Pirta Hotulainen
- Minerva Foundation Institute for Medical Research, Helsinki, Finland
| | - Frédéric A Meunier
- Clem Jones Centre for Ageing Dementia Research, Queensland Brain Institute, The University of Queensland, Brisbane, Australia
| | - Tong Wang
- Center for Brain Science, School of Life Science and Technology, Shanghaitech University, Shanghai, China
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37
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Trans-synaptic degeneration in the visual pathway: Neural connectivity, pathophysiology, and clinical implications in neurodegenerative disorders. Surv Ophthalmol 2021; 67:411-426. [PMID: 34146577 DOI: 10.1016/j.survophthal.2021.06.001] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2021] [Revised: 06/06/2021] [Accepted: 06/07/2021] [Indexed: 12/13/2022]
Abstract
There is a strong interrelationship between eye and brain diseases. It has been shown that neurodegenerative changes can spread bidirectionally in the visual pathway along neuronal projections. For example, damage to retinal ganglion cells in the retina leads to degeneration of the visual cortex (anterograde degeneration) and vice versa (retrograde degeneration). The underlying mechanisms of this process, known as trans-synaptic degeneration (TSD), are unknown, but TSD contributes to the progression of numerous neurodegenerative disorders, leading to clinical and functional deterioration. The hierarchical structure of the visual system comprises of a strong topographic connectivity between the retina and the visual cortex and therefore serves as an ideal model to study the cellular effect, clinical manifestations, and deterioration extent of TSD. With this review we provide comprehensive information about the neural connectivity, synapse function, molecular changes, and pathophysiology of TSD in visual pathways. We then discuss its bidirectional nature and clinical implications in neurodegenerative diseases. A thorough understanding of TSD in the visual pathway can provide insights into progression of neurodegenerative disorders and its potential as a therapeutic target.
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38
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Retinoid X Receptor α Regulates DHA-Dependent Spinogenesis and Functional Synapse Formation In Vivo. Cell Rep 2021; 31:107649. [PMID: 32433958 DOI: 10.1016/j.celrep.2020.107649] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2019] [Revised: 02/01/2020] [Accepted: 04/22/2020] [Indexed: 12/23/2022] Open
Abstract
Coordinated intracellular and extracellular signaling is critical to synapse development and functional neural circuit wiring. Here, we report that unesterified docosahexaenoic acid (DHA) regulates functional synapse formation in vivo via retinoid X receptor α (Rxra) signaling. Using Rxra conditional knockout (cKO) mice and virus-mediated transient gene expression, we show that endogenous Rxra plays important roles in regulating spinogenesis and excitatory synaptic transmission in cortical pyramidal neurons. We further show that the effects of RXRA are mediated through its DNA-binding domain in a cell-autonomous and reversible manner. Moreover, unesterified DHA increases spine formation and excitatory synaptic transmission in vivo in an Rxra-dependent fashion. Rxra cKO mice generally behave normally but show deficits in behavior tasks associated with social memory. Together, these results demonstrate that unesterified DHA signals through RXRA to regulate spinogenesis and functional synapse formation, providing insight into the mechanism through which DHA promotes brain development and cognitive function.
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Lasseigne AM, Echeverry FA, Ijaz S, Michel JC, Martin EA, Marsh AJ, Trujillo E, Marsden KC, Pereda AE, Miller AC. Electrical synaptic transmission requires a postsynaptic scaffolding protein. eLife 2021; 10:e66898. [PMID: 33908867 PMCID: PMC8081524 DOI: 10.7554/elife.66898] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2021] [Accepted: 03/30/2021] [Indexed: 02/06/2023] Open
Abstract
Electrical synaptic transmission relies on neuronal gap junctions containing channels constructed by Connexins. While at chemical synapses neurotransmitter-gated ion channels are critically supported by scaffolding proteins, it is unknown if channels at electrical synapses require similar scaffold support. Here, we investigated the functional relationship between neuronal Connexins and Zonula Occludens 1 (ZO1), an intracellular scaffolding protein localized to electrical synapses. Using model electrical synapses in zebrafish Mauthner cells, we demonstrated that ZO1 is required for robust synaptic Connexin localization, but Connexins are dispensable for ZO1 localization. Disrupting this hierarchical ZO1/Connexin relationship abolishes electrical transmission and disrupts Mauthner cell-initiated escape responses. We found that ZO1 is asymmetrically localized exclusively postsynaptically at neuronal contacts where it functions to assemble intercellular channels. Thus, forming functional neuronal gap junctions requires a postsynaptic scaffolding protein. The critical function of a scaffolding molecule reveals an unanticipated complexity of molecular and functional organization at electrical synapses.
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Affiliation(s)
| | - Fabio A Echeverry
- Dominick P. Purpura Department of Neuroscience, Albert Einstein College of MedicineBronxUnited States
| | - Sundas Ijaz
- Dominick P. Purpura Department of Neuroscience, Albert Einstein College of MedicineBronxUnited States
| | | | - E Anne Martin
- Institute of Neuroscience, University of OregonEugeneUnited States
| | - Audrey J Marsh
- Institute of Neuroscience, University of OregonEugeneUnited States
| | - Elisa Trujillo
- Institute of Neuroscience, University of OregonEugeneUnited States
| | - Kurt C Marsden
- Department of Biological Sciences, NC State UniversityRaleighUnited States
| | - Alberto E Pereda
- Dominick P. Purpura Department of Neuroscience, Albert Einstein College of MedicineBronxUnited States
| | - Adam C Miller
- Institute of Neuroscience, University of OregonEugeneUnited States
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40
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Hayashi S, Hoerder-Suabedissen A, Kiyokage E, Maclachlan C, Toida K, Knott G, Molnár Z. Maturation of Complex Synaptic Connections of Layer 5 Cortical Axons in the Posterior Thalamic Nucleus Requires SNAP25. Cereb Cortex 2021; 31:2625-2638. [PMID: 33367517 PMCID: PMC8023812 DOI: 10.1093/cercor/bhaa379] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2020] [Revised: 11/16/2020] [Accepted: 11/19/2020] [Indexed: 02/06/2023] Open
Abstract
Synapses are able to form in the absence of neuronal activity, but how is their subsequent maturation affected in the absence of regulated vesicular release? We explored this question using 3D electron microscopy and immunoelectron microscopy analyses in the large, complex synapses formed between cortical sensory efferent axons and dendrites in the posterior thalamic nucleus. Using a Synaptosome-associated protein 25 conditional knockout (Snap25 cKO), we found that during the first 2 postnatal weeks the axonal boutons emerge and increase in the size similar to the control animals. However, by P18, when an adult-like architecture should normally be established, axons were significantly smaller with 3D reconstructions, showing that each Snap25 cKO bouton only forms a single synapse with the connecting dendritic shaft. No excrescences from the dendrites were formed, and none of the normally large glomerular axon endings were seen. These results show that activity mediated through regulated vesicular release from the presynaptic terminal is not necessary for the formation of synapses, but it is required for the maturation of the specialized synaptic structures between layer 5 corticothalamic projections in the posterior thalamic nucleus.
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Affiliation(s)
- Shuichi Hayashi
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford OX1 3PT, United Kingdom
- Department of Anatomy, Kawasaki Medical School, Kurashiki, Okayama 701-0192, Japan
| | - Anna Hoerder-Suabedissen
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford OX1 3PT, United Kingdom
| | - Emi Kiyokage
- Department of Medical Technology, Kawasaki University of Medical Welfare, Kurashiki, Okayama 701-0193, Japan
| | - Catherine Maclachlan
- BioEM Facility, School of Life Sciences, EPFL, Lausanne 1015, Switzerland
- The Francis Crick Institute, London NW1 1AT, United Kingdom
| | - Kazunori Toida
- Department of Anatomy, Kawasaki Medical School, Kurashiki, Okayama 701-0192, Japan
- Research Center for Ultra-High Voltage Electron Microscopy, Osaka University, Ibaraki, Osaka 567-0047, Japan
| | - Graham Knott
- BioEM Facility, School of Life Sciences, EPFL, Lausanne 1015, Switzerland
| | - Zoltán Molnár
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford OX1 3PT, United Kingdom
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41
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Kamimura K, Maeda N. Glypicans and Heparan Sulfate in Synaptic Development, Neural Plasticity, and Neurological Disorders. Front Neural Circuits 2021; 15:595596. [PMID: 33679334 PMCID: PMC7928303 DOI: 10.3389/fncir.2021.595596] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2020] [Accepted: 01/11/2021] [Indexed: 12/16/2022] Open
Abstract
Heparan sulfate proteoglycans (HSPGs) are components of the cell surface and extracellular matrix, which bear long polysaccharides called heparan sulfate (HS) attached to the core proteins. HSPGs interact with a variety of ligand proteins through the HS chains, and mutations in HSPG-related genes influence many biological processes and cause various diseases. In particular, recent findings from vertebrate and invertebrate studies have raised the importance of glycosylphosphatidylinositol-anchored HSPGs, glypicans, as central players in the development and functions of synapses. Glypicans are important components of the synapse-organizing protein complexes and serve as ligands for leucine-rich repeat transmembrane neuronal proteins (LRRTMs), leukocyte common antigen-related (LAR) family receptor protein tyrosine phosphatases (RPTPs), and G-protein-coupled receptor 158 (GPR158), regulating synapse formation. Many of these interactions are mediated by the HS chains of glypicans. Neurexins (Nrxs) are also synthesized as HSPGs and bind to some ligands in common with glypicans through HS chains. Therefore, glypicans and Nrxs may act competitively at the synapses. Furthermore, glypicans regulate the postsynaptic expression levels of ionotropic glutamate receptors, controlling the electrophysiological properties and non-canonical BMP signaling of synapses. Dysfunctions of glypicans lead to failures in neuronal network formation, malfunction of synapses, and abnormal behaviors that are characteristic of neurodevelopmental disorders. Recent human genetics revealed that glypicans and HS are associated with autism spectrum disorder, neuroticism, and schizophrenia. In this review, we introduce the studies showing the roles of glypicans and HS in synapse formation, neural plasticity, and neurological disorders, especially focusing on the mouse and Drosophila as potential models for human diseases.
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Affiliation(s)
- Keisuke Kamimura
- Developmental Neuroscience Project, Department of Brain and Neurosciences, Tokyo Metropolitan Institute of Medical Science, Setagaya, Japan
| | - Nobuaki Maeda
- Developmental Neuroscience Project, Department of Brain and Neurosciences, Tokyo Metropolitan Institute of Medical Science, Setagaya, Japan
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42
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Jang S, Yang E, Kim D, Kim H, Kim E. Clmp Regulates AMPA and Kainate Receptor Responses in the Neonatal Hippocampal CA3 and Kainate Seizure Susceptibility in Mice. Front Synaptic Neurosci 2021; 12:567075. [PMID: 33408624 PMCID: PMC7779639 DOI: 10.3389/fnsyn.2020.567075] [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: 06/11/2020] [Accepted: 12/02/2020] [Indexed: 12/05/2022] Open
Abstract
Synaptic adhesion molecules regulate synapse development through trans-synaptic adhesion and assembly of diverse synaptic proteins. Many synaptic adhesion molecules positively regulate synapse development; some, however, exert negative regulation, although such cases are relatively rare. In addition, synaptic adhesion molecules regulate the amplitude of post-synaptic receptor responses, but whether adhesion molecules can regulate the kinetic properties of post-synaptic receptors remains unclear. Here we report that Clmp, a homophilic adhesion molecule of the Ig domain superfamily that is abundantly expressed in the brain, reaches peak expression at a neonatal stage (week 1) and associates with subunits of AMPA receptors (AMPARs) and kainate receptors (KARs). Clmp deletion in mice increased the frequency and amplitude of AMPAR-mediated miniature excitatory post-synaptic currents (mEPSCs) and the frequency, amplitude, and decay time constant of KAR-mediated mEPSCs in hippocampal CA3 neurons. Clmp deletion had minimal impacts on evoked excitatory synaptic currents at mossy fiber-CA3 synapses but increased extrasynaptic KAR, but not AMPAR, currents, suggesting that Clmp distinctly inhibits AMPAR and KAR responses. Behaviorally, Clmp deletion enhanced novel object recognition and susceptibility to kainate-induced seizures, without affecting contextual or auditory cued fear conditioning or pattern completion-based contextual fear conditioning. These results suggest that Clmp negatively regulates hippocampal excitatory synapse development and AMPAR and KAR responses in the neonatal hippocampal CA3 as well as object recognition and kainate seizure susceptibility in mice.
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Affiliation(s)
- Seil Jang
- Center for Synaptic Brain Dysfunctions, Institute for Basic Science, Daejeon, South Korea
| | - Esther Yang
- Department of Anatomy and Division of Brain Korea 21, Biomedical Science, College of Medicine, Korea University, Seoul, South Korea
| | - Doyoun Kim
- Center for Drug Discovery Platform Research, Korea Research Institute of Chemical Technology (KRICT), Daejeon, South Korea
| | - Hyun Kim
- Department of Anatomy and Division of Brain Korea 21, Biomedical Science, College of Medicine, Korea University, Seoul, South Korea
| | - Eunjoon Kim
- Center for Synaptic Brain Dysfunctions, Institute for Basic Science, Daejeon, South Korea.,Department of Biological Sciences, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, South Korea
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43
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Blockus H, Polleux F. Developmental mechanisms underlying circuit wiring: Novel insights and challenges ahead. Curr Opin Neurobiol 2021; 66:205-211. [PMID: 33421713 PMCID: PMC8058300 DOI: 10.1016/j.conb.2020.12.013] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2020] [Revised: 12/13/2020] [Accepted: 12/15/2020] [Indexed: 12/31/2022]
Abstract
Synaptic connectivity within neural circuits is characterized by high degrees of cellular and subcellular specificity. This precision arises from the combined action of several classes of molecular cues, transmembrane receptors, secreted cues and extracellular matrix components, coordinating transitions between axon guidance, dendrite patterning, axon branching and synapse specificity. We focus this review on recent insights into some of the molecular and cellular mechanisms controlling these transitions and present the results of large-scale efforts and technological developments aimed at mapping neural connectivity at single cell resolution in the mouse cortex as a mammalian model organism. Finally, we outline some of the technical and conceptual challenges lying ahead as the field is starting to explore one of the most challenging problems in neuroscience: the molecular and cellular logic underlying the emergence of the connectome characterizing specific circuits within the central nervous system of mammals.
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Affiliation(s)
- Heike Blockus
- Department of Neuroscience, Columbia University, New York, NY 10027, USA; Zuckerman Mind Brain Behavior Institute, Columbia University, New York, NY 10027, USA.
| | - Franck Polleux
- Department of Neuroscience, Columbia University, New York, NY 10027, USA; Zuckerman Mind Brain Behavior Institute, Columbia University, New York, NY 10027, USA; Kavli Institute for Brain Science, Columbia University, New York, NY 10027, USA.
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44
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Fukai S, Yoshida T. Roles of type IIa receptor protein tyrosine phosphatases as synaptic organizers. FEBS J 2020; 288:6913-6926. [PMID: 33301645 DOI: 10.1111/febs.15666] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2020] [Revised: 11/26/2020] [Accepted: 12/08/2020] [Indexed: 12/14/2022]
Abstract
Neurons establish circuits for brain functions such as cognition, emotion, learning, and memory. Their connections are mediated by synapses, which are specialized cell-cell adhesions responsible for neuronal signal transmission. During neurodevelopment, synapse formation is triggered by interactions of cell adhesion molecules termed synaptic organizers or synapse organizers. Type IIa receptor protein tyrosine phosphatases (IIa RPTPs; also known as leukocyte common antigen-related receptor tyrosine phosphatases or LAR-RPTPs) play important roles in axon guidance and neurite extension, and also serve as presynaptic organizers. IIa RPTPs transsynaptically interact with multiple sets of postsynaptic organizers, mostly in a splicing-dependent fashion. Here, we review and update research progress on IIa RPTPs, particularly regarding their functional roles in vivo demonstrated using conditional knockout approach and structural insights into their extracellular and intracellular molecular interactions revealed by crystallography and other biophysical techniques. Future directions in the research field of IIa RPTPs are also discussed, including recent findings of the molecular assembly mechanism underlying the formation of synapse-specific nanostructures essential for synaptic functions.
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Affiliation(s)
- Shuya Fukai
- Department of Chemistry, Graduate School of Science, Kyoto University, Japan
| | - Tomoyuki Yoshida
- Department of Molecular Neuroscience, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Japan
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45
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Lee AK, Khaled H, Chofflet N, Takahashi H. Synaptic Organizers in Alzheimer's Disease: A Classification Based on Amyloid-β Sensitivity. Front Cell Neurosci 2020; 14:281. [PMID: 32982693 PMCID: PMC7492772 DOI: 10.3389/fncel.2020.00281] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2020] [Accepted: 08/10/2020] [Indexed: 12/25/2022] Open
Abstract
Synaptic pathology is one of the major hallmarks observed from the early stage of Alzheimer’s disease (AD), leading to cognitive and memory impairment characteristic of AD patients. Synaptic connectivity and specificity are regulated by multiple trans-bindings between pre- and post-synaptic organizers, the complex of which exerts synaptogenic activity. Neurexins (NRXs) and Leukocyte common antigen-related receptor protein tyrosine phosphatases (LAR-RPTPs) are the major presynaptic organizers promoting synaptogenesis through their distinct binding to a wide array of postsynaptic organizers. Recent studies have shown that amyloid-β oligomers (AβOs), a major detrimental molecule in AD, interact with NRXs and neuroligin-1, an NRX-binding postsynaptic organizer, to cause synaptic impairment. On the other hand, LAR-RPTPs and their postsynaptic binding partners have no interaction with AβOs, and their synaptogenic activity is maintained even in the presence of AβOs. Here, we review the current evidence regarding the involvement of synaptic organizers in AD, with a focus on Aβ synaptic pathology, to propose a new classification where NRX-based and LAR-RPTP-based synaptic organizing complexes are classified into Aβ-sensitive and Aβ-insensitive synaptic organizers, respectively. We further discuss how their different Aβ sensitivity is involved in Aβ vulnerability and tolerance of synapses for exploring potential therapeutic approaches for AD.
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Affiliation(s)
- Alfred Kihoon Lee
- Synapse Development and Plasticity Research Unit, Institut de Recherches Cliniques de Montréal (IRCM), Montreal, QC, Canada.,Integrated Program in Neuroscience, McGill University, Montreal, QC, Canada
| | - Husam Khaled
- Synapse Development and Plasticity Research Unit, Institut de Recherches Cliniques de Montréal (IRCM), Montreal, QC, Canada.,Molecular Biology Program, Université de Montréal, Montréal, QC, Canada
| | - Nicolas Chofflet
- Synapse Development and Plasticity Research Unit, Institut de Recherches Cliniques de Montréal (IRCM), Montreal, QC, Canada.,Integrated Program in Neuroscience, McGill University, Montreal, QC, Canada
| | - Hideto Takahashi
- Synapse Development and Plasticity Research Unit, Institut de Recherches Cliniques de Montréal (IRCM), Montreal, QC, Canada.,Integrated Program in Neuroscience, McGill University, Montreal, QC, Canada.,Molecular Biology Program, Université de Montréal, Montréal, QC, Canada.,Department of Medicine, Université de Montréal, Montreal, QC, Canada.,Division of Experimental Medicine, McGill University, Montreal, QC, Canada
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46
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Suzuki K, Elegheert J, Song I, Sasakura H, Senkov O, Matsuda K, Kakegawa W, Clayton AJ, Chang VT, Ferrer-Ferrer M, Miura E, Kaushik R, Ikeno M, Morioka Y, Takeuchi Y, Shimada T, Otsuka S, Stoyanov S, Watanabe M, Takeuchi K, Dityatev A, Aricescu AR, Yuzaki M. A synthetic synaptic organizer protein restores glutamatergic neuronal circuits. Science 2020; 369:369/6507/eabb4853. [PMID: 32855309 PMCID: PMC7116145 DOI: 10.1126/science.abb4853] [Citation(s) in RCA: 65] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2020] [Accepted: 07/24/2020] [Indexed: 12/18/2022]
Abstract
Neuronal synapses undergo structural and functional changes throughout life, which are essential for nervous system physiology. However, these changes may also perturb the excitatory-inhibitory neurotransmission balance and trigger neuropsychiatric and neurological disorders. Molecular tools to restore this balance are highly desirable. Here, we designed and characterized CPTX, a synthetic synaptic organizer combining structural elements from cerebellin-1 and neuronal pentraxin-1. CPTX can interact with presynaptic neurexins and postsynaptic AMPA-type ionotropic glutamate receptors and induced the formation of excitatory synapses both in vitro and in vivo. CPTX restored synaptic functions, motor coordination, spatial and contextual memories, and locomotion in mouse models for cerebellar ataxia, Alzheimer's disease, and spinal cord injury, respectively. Thus, CPTX represents a prototype for structure-guided biologics that can efficiently repair or remodel neuronal circuits.
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Affiliation(s)
- Kunimichi Suzuki
- Department of Physiology, Keio University School of Medicine, Tokyo 160-8582, Japan
| | - Jonathan Elegheert
- Division of Structural Biology, University of Oxford, Oxford OX3 7BN, UK
| | - Inseon Song
- Molecular Neuroplasticity, German Center for Neurodegenerative Diseases (DZNE), 39120 Magdeburg, Germany
| | - Hiroyuki Sasakura
- Department of Medical Cell Biology, School of Medicine, Aichi Medical University, Aichi, Japan
| | - Oleg Senkov
- Molecular Neuroplasticity, German Center for Neurodegenerative Diseases (DZNE), 39120 Magdeburg, Germany
| | - Keiko Matsuda
- Department of Physiology, Keio University School of Medicine, Tokyo 160-8582, Japan
| | - Wataru Kakegawa
- Department of Physiology, Keio University School of Medicine, Tokyo 160-8582, Japan
| | - Amber J Clayton
- Division of Structural Biology, University of Oxford, Oxford OX3 7BN, UK
| | - Veronica T Chang
- Division of Structural Biology, University of Oxford, Oxford OX3 7BN, UK
- Neurobiology Division, MRC Laboratory of Molecular Biology, Cambridge CB2 0QH, UK
| | - Maura Ferrer-Ferrer
- Molecular Neuroplasticity, German Center for Neurodegenerative Diseases (DZNE), 39120 Magdeburg, Germany
| | - Eriko Miura
- Department of Physiology, Keio University School of Medicine, Tokyo 160-8582, Japan
| | - Rahul Kaushik
- Molecular Neuroplasticity, German Center for Neurodegenerative Diseases (DZNE), 39120 Magdeburg, Germany
- Center for Behavioral Brain Sciences (CBBS), 39106 Magdeburg, Germany
| | - Masashi Ikeno
- Department of Medical Cell Biology, School of Medicine, Aichi Medical University, Aichi, Japan
| | - Yuki Morioka
- Department of Medical Cell Biology, School of Medicine, Aichi Medical University, Aichi, Japan
| | - Yuka Takeuchi
- Department of Medical Cell Biology, School of Medicine, Aichi Medical University, Aichi, Japan
| | - Tatsuya Shimada
- Department of Physiology, Keio University School of Medicine, Tokyo 160-8582, Japan
| | - Shintaro Otsuka
- Department of Physiology, Keio University School of Medicine, Tokyo 160-8582, Japan
| | - Stoyan Stoyanov
- Molecular Neuroplasticity, German Center for Neurodegenerative Diseases (DZNE), 39120 Magdeburg, Germany
| | - Masahiko Watanabe
- Department of Anatomy, Hokkaido University Graduate School of Medicine, Sapporo 060-8638, Japan
| | - Kosei Takeuchi
- Department of Medical Cell Biology, School of Medicine, Aichi Medical University, Aichi, Japan
| | - Alexander Dityatev
- Molecular Neuroplasticity, German Center for Neurodegenerative Diseases (DZNE), 39120 Magdeburg, Germany.
- Center for Behavioral Brain Sciences (CBBS), 39106 Magdeburg, Germany
- Medical Faculty, Otto von Guericke University, 39120 Magdeburg, Germany
| | - A Radu Aricescu
- Division of Structural Biology, University of Oxford, Oxford OX3 7BN, UK.
- Neurobiology Division, MRC Laboratory of Molecular Biology, Cambridge CB2 0QH, UK
| | - Michisuke Yuzaki
- Department of Physiology, Keio University School of Medicine, Tokyo 160-8582, Japan.
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47
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Briatore F, Pregno G, Di Angelantonio S, Frola E, De Stefano ME, Vaillend C, Sassoè-Pognetto M, Patrizi A. Dystroglycan Mediates Clustering of Essential GABAergic Components in Cerebellar Purkinje Cells. Front Mol Neurosci 2020; 13:164. [PMID: 32982691 PMCID: PMC7485281 DOI: 10.3389/fnmol.2020.00164] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2020] [Accepted: 08/11/2020] [Indexed: 01/02/2023] Open
Abstract
Muscle dystrophin–glycoprotein complex (DGC) links the intracellular cytoskeleton to the extracellular matrix. In neurons, dystroglycan and dystrophin, two major components of the DGC, localize in a subset of GABAergic synapses, where their function is unclear. Here we used mouse models to analyze the specific role of the DGC in the organization and function of inhibitory synapses. Loss of full-length dystrophin in mdx mice resulted in a selective depletion of the transmembrane β-dystroglycan isoform from inhibitory post-synaptic sites in cerebellar Purkinje cells. Remarkably, there were no differences in the synaptic distribution of the extracellular α-dystroglycan subunit, of GABAA receptors and neuroligin 2. In contrast, conditional deletion of the dystroglycan gene from Purkinje cells caused a disruption of the DGC and severely impaired post-synaptic clustering of neuroligin 2, GABAA receptors and scaffolding proteins. Accordingly, whole-cell patch-clamp analysis revealed a significant reduction in the frequency and amplitude of spontaneous IPSCs recorded from Purkinje cells. In the long-term, deletion of dystroglycan resulted in a significant decrease of GABAergic innervation of Purkinje cells and caused an impairment of motor learning functions. These results show that dystroglycan is an essential synaptic organizer at GABAergic synapses in Purkinje cells.
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Affiliation(s)
- Federica Briatore
- Department of Neuroscience "Rita Levi Montalcini", University of Turin, Turin, Italy
| | - Giulia Pregno
- Department of Neuroscience "Rita Levi Montalcini", University of Turin, Turin, Italy
| | - Silvia Di Angelantonio
- Department of Physiology and Pharmacology, Sapienza University of Rome, Rome, Italy.,Center for Life Nanoscience, Istituto Italiano di Tecnologia, Rome, Italy
| | - Elena Frola
- Department of Neuroscience "Rita Levi Montalcini", University of Turin, Turin, Italy
| | - Maria Egle De Stefano
- Department of Biology and Biotechnology "Charles Darwin", Istituto Pasteur Italia-Fondazione Cenci Bolognetti, Sapienza University of Rome, Rome, Italy
| | - Cyrille Vaillend
- CNRS, Institut des Neurosciences Paris-Saclay, Université Paris-Saclay, Gif-sur-Yvette, France
| | - Marco Sassoè-Pognetto
- Department of Neuroscience "Rita Levi Montalcini", University of Turin, Turin, Italy
| | - Annarita Patrizi
- Department of Neuroscience "Rita Levi Montalcini", University of Turin, Turin, Italy.,Schaller Research Group Leader at the German Cancer Research Center, Heidelberg, Germany
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48
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Agosto MA, Wensel TG. LRRTM4 is a member of the transsynaptic complex between rod photoreceptors and bipolar cells. J Comp Neurol 2020; 529:221-233. [PMID: 32390181 DOI: 10.1002/cne.24944] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2020] [Revised: 04/09/2020] [Accepted: 05/01/2020] [Indexed: 12/22/2022]
Abstract
Leucine rich repeat transmembrane (LRRTM) proteins are synaptic adhesion molecules with roles in synapse formation and signaling. LRRTM4 transcripts were previously shown to be enriched in rod bipolar cells (BCs), secondary neurons of the retina that form synapses with rod photoreceptors. Using two different antibodies, LRRTM4 was found to reside primarily at rod BC dendritic tips, where it colocalized with the transduction channel protein, TRPM1. LRRTM4 was not detected at dendritic tips of ON-cone BCs. Following somatic knockout of LRRTM4 in BCs by subretinal injection and electroporation of CRISPR/Cas9, LRRTM4 was abolished or reduced in the dendritic tips of transfected cells. Knockout cells had a normal complement of TRPM1 at their dendritic tips, while GPR179 accumulation was partially reduced. In experiments with heterologously expressed protein, the extracellular domain of LRRTM4 was found to engage in heparan-sulfate dependent binding with pikachurin. These results implicate LRRTM4 in the GPR179-pikachurin-dystroglycan transsynaptic complex at rod synapses.
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Affiliation(s)
- Melina A Agosto
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, Texas, USA
| | - Theodore G Wensel
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, Texas, USA
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49
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Park H, Choi Y, Jung H, Kim S, Lee S, Han H, Kweon H, Kang S, Sim WS, Koopmans F, Yang E, Kim H, Smit AB, Bae YC, Kim E. Splice-dependent trans-synaptic PTPδ-IL1RAPL1 interaction regulates synapse formation and non-REM sleep. EMBO J 2020; 39:e104150. [PMID: 32347567 PMCID: PMC7265247 DOI: 10.15252/embj.2019104150] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2019] [Revised: 03/17/2020] [Accepted: 03/23/2020] [Indexed: 12/12/2022] Open
Abstract
Alternative splicing regulates trans‐synaptic adhesions and synapse development, but supporting in vivo evidence is limited. PTPδ, a receptor tyrosine phosphatase adhering to multiple synaptic adhesion molecules, is associated with various neuropsychiatric disorders; however, its in vivo functions remain unclear. Here, we show that PTPδ is mainly present at excitatory presynaptic sites by endogenous PTPδ tagging. Global PTPδ deletion in mice leads to input‐specific decreases in excitatory synapse development and strength. This involves tyrosine dephosphorylation and synaptic loss of IL1RAPL1, a postsynaptic partner of PTPδ requiring the PTPδ‐meA splice insert for binding. Importantly, PTPδ‐mutant mice lacking the PTPδ‐meA insert, and thus lacking the PTPδ interaction with IL1RAPL1 but not other postsynaptic partners, recapitulate biochemical and synaptic phenotypes of global PTPδ‐mutant mice. Behaviorally, both global and meA‐specific PTPδ‐mutant mice display abnormal sleep behavior and non‐REM rhythms. Therefore, alternative splicing in PTPδ regulates excitatory synapse development and sleep by modulating a specific trans‐synaptic adhesion.
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Affiliation(s)
- Haram Park
- Center for Synaptic Brain Dysfunctions, Institute for Basic Science (IBS), Daejeon, Korea
| | - Yeonsoo Choi
- Center for Synaptic Brain Dysfunctions, Institute for Basic Science (IBS), Daejeon, Korea
| | - Hwajin Jung
- Center for Synaptic Brain Dysfunctions, Institute for Basic Science (IBS), Daejeon, Korea
| | - Seoyeong Kim
- Department of Biological Sciences, Korea Advanced Institute for Science and Technology (KAIST), Daejeon, Korea
| | - Suho Lee
- Center for Synaptic Brain Dysfunctions, Institute for Basic Science (IBS), Daejeon, Korea
| | - Hyemin Han
- Department of Anatomy and Neurobiology, School of Dentistry, Kyungpook National University, Daegu, Korea
| | - Hanseul Kweon
- Department of Biological Sciences, Korea Advanced Institute for Science and Technology (KAIST), Daejeon, Korea
| | - Suwon Kang
- Department of Biological Sciences, Korea Advanced Institute for Science and Technology (KAIST), Daejeon, Korea
| | - Woong Seob Sim
- Department of Biological Sciences, Korea Advanced Institute for Science and Technology (KAIST), Daejeon, Korea
| | - Frank Koopmans
- Department of Functional Genomics, CNCR, VU University and UMC Amsterdam, Amsterdam, The Netherlands.,Department of Molecular and Cellular Neurobiology, CNCR, VU University and UMC Amsterdam, Amsterdam, The Netherlands
| | - Esther Yang
- Department of Anatomy and Division of Brain Korea 21, Biomedical Science, College of Medicine, Korea University, Seoul, Korea
| | - Hyun Kim
- Department of Anatomy and Division of Brain Korea 21, Biomedical Science, College of Medicine, Korea University, Seoul, Korea
| | - August B Smit
- Department of Molecular and Cellular Neurobiology, CNCR, VU University and UMC Amsterdam, Amsterdam, The Netherlands
| | - Yong Chul Bae
- Department of Anatomy and Neurobiology, School of Dentistry, Kyungpook National University, Daegu, Korea
| | - Eunjoon Kim
- Center for Synaptic Brain Dysfunctions, Institute for Basic Science (IBS), Daejeon, Korea.,Department of Biological Sciences, Korea Advanced Institute for Science and Technology (KAIST), Daejeon, Korea
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50
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Sasaki Y. Local Translation in Growth Cones and Presynapses, Two Axonal Compartments for Local Neuronal Functions. Biomolecules 2020; 10:biom10050668. [PMID: 32344905 PMCID: PMC7277458 DOI: 10.3390/biom10050668] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2020] [Revised: 04/08/2020] [Accepted: 04/21/2020] [Indexed: 01/02/2023] Open
Abstract
During neural development, growth cones, very motile compartments of tips of axons, lead axonal extension to the correct targets. Subsequently, presynapses, another axonal compartment with vigorous trafficking of synaptic vesicles, emerge to form functional synapses with postsynapses. In response to extracellular stimuli, the immediate supply of proteins by local translation within these two axonal compartments far from cell bodies confers high motility of growth cones and active vesicle trafficking in presynapses. Although local translation in growth cones and presynapses occurs at a very low level compared with cell bodies and even dendrites, recent progress in omics and visualization techniques with subcellular fractionation of these compartments has revealed the actual situation of local translation within these two axonal compartments. Here, the increasing evidence for local protein synthesis in growth cones and presynapses for axonal and synaptic functions has been reviewed. Furthermore, the mechanisms regulating local translation in these two compartments and pathophysiological conditions caused by dysregulated local translation are highlighted.
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Affiliation(s)
- Yukio Sasaki
- Functional Structure Biology Laboratory, Department of Medical Life Science, Yokohama City University Graduate School of Medical Life Science, 1-7-29 Suehiro-cho, Tsurumi-ku, Yokohama 230-0045, Japan
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