1
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Nowacka A, Getz AM, Bessa-Neto D, Choquet D. Activity-dependent diffusion trapping of AMPA receptors as a key step for expression of early LTP. Philos Trans R Soc Lond B Biol Sci 2024; 379:20230220. [PMID: 38853553 DOI: 10.1098/rstb.2023.0220] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2024] [Accepted: 04/11/2024] [Indexed: 06/11/2024] Open
Abstract
This review focuses on the activity-dependent diffusion trapping of α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptors (AMPARs) as a crucial mechanism for the expression of early long-term potentiation (LTP), a process central to learning and memory. Despite decades of research, the precise mechanisms by which LTP induction leads to an increase in AMPAR responses at synapses have been elusive. We review the different hypotheses that have been put forward to explain the increased AMPAR responsiveness during LTP. We discuss the dynamic nature of AMPAR complexes, including their constant turnover and activity-dependent modifications that affect their synaptic accumulation. We highlight a hypothesis suggesting that AMPARs are diffusively trapped at synapses through activity-dependent interactions with protein-based binding slots in the post-synaptic density (PSD), offering a potential explanation for the increased synaptic strength during LTP. Furthermore, we outline the challenges still to be addressed before we fully understand the functional roles and molecular mechanisms of AMPAR dynamic nanoscale organization in LTP. This article is part of a discussion meeting issue 'Long-term potentiation: 50 years on'.
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Affiliation(s)
- Agata Nowacka
- University of Bordeaux, CNRS, Interdisciplinary Institute for Neuroscience, IINS, UMR 5297 , Bordeaux F-33000, France
| | - Angela M Getz
- University of Bordeaux, CNRS, Interdisciplinary Institute for Neuroscience, IINS, UMR 5297 , Bordeaux F-33000, France
- University of Bordeaux, CNRS, INSERM, Bordeaux Imaging Center, BIC, UMS 3420, US 4 , Bordeaux F-33000, France
| | - Diogo Bessa-Neto
- University of Bordeaux, CNRS, Interdisciplinary Institute for Neuroscience, IINS, UMR 5297 , Bordeaux F-33000, France
| | - Daniel Choquet
- University of Bordeaux, CNRS, Interdisciplinary Institute for Neuroscience, IINS, UMR 5297 , Bordeaux F-33000, France
- University of Bordeaux, CNRS, INSERM, Bordeaux Imaging Center, BIC, UMS 3420, US 4 , Bordeaux F-33000, France
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2
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Harris KM, Kuwajima M, Flores JC, Zito K. Synapse-specific structural plasticity that protects and refines local circuits during LTP and LTD. Philos Trans R Soc Lond B Biol Sci 2024; 379:20230224. [PMID: 38853547 DOI: 10.1098/rstb.2023.0224] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2023] [Accepted: 01/05/2024] [Indexed: 06/11/2024] Open
Abstract
Synapses form trillions of connections in the brain. Long-term potentiation (LTP) and long-term depression (LTD) are cellular mechanisms vital for learning that modify the strength and structure of synapses. Three-dimensional reconstruction from serial section electron microscopy reveals three distinct pre- to post-synaptic arrangements: strong active zones (AZs) with tightly docked vesicles, weak AZs with loose or non-docked vesicles, and nascent zones (NZs) with a postsynaptic density but no presynaptic vesicles. Importantly, LTP can be temporarily saturated preventing further increases in synaptic strength. At the onset of LTP, vesicles are recruited to NZs, converting them to AZs. During recovery of LTP from saturation (1-4 h), new NZs form, especially on spines where AZs are most enlarged by LTP. Sentinel spines contain smooth endoplasmic reticulum (SER), have the largest synapses and form clusters with smaller spines lacking SER after LTP recovers. We propose a model whereby NZ plasticity provides synapse-specific AZ expansion during LTP and loss of weak AZs that drive synapse shrinkage during LTD. Spine clusters become functionally engaged during LTP or disassembled during LTD. Saturation of LTP or LTD probably acts to protect recently formed memories from ongoing plasticity and may account for the advantage of spaced over massed learning. This article is part of a discussion meeting issue 'Long-term potentiation: 50 years on'.
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Affiliation(s)
- Kristen M Harris
- Department of Neuroscience and Center for Learning and Memory, The University of Texas at Austin , Austin, TX 78712, USA
| | - Masaaki Kuwajima
- Department of Neuroscience and Center for Learning and Memory, The University of Texas at Austin , Austin, TX 78712, USA
| | - Juan C Flores
- Center for Neuroscience, University of California , Davis, CA 95618, USA
| | - Karen Zito
- Center for Neuroscience, University of California , Davis, CA 95618, USA
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3
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Fukata Y, Fukata M, MacGillavry HD, Nair D, Hosy E. Celebrating the Birthday of AMPA Receptor Nanodomains: Illuminating the Nanoscale Organization of Excitatory Synapses with 10 Nanocandles. J Neurosci 2024; 44:e2104232024. [PMID: 38839340 PMCID: PMC11154862 DOI: 10.1523/jneurosci.2104-23.2024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2023] [Revised: 04/02/2024] [Accepted: 04/03/2024] [Indexed: 06/07/2024] Open
Abstract
A decade ago, in 2013, and over the course of 4 summer months, three separate observations were reported that each shed light independently on a new molecular organization that fundamentally reshaped our perception of excitatory synaptic transmission (Fukata et al., 2013; MacGillavry et al., 2013; Nair et al., 2013). This discovery unveiled an intricate arrangement of AMPA-type glutamate receptors and their principal scaffolding protein PSD-95, at synapses. This breakthrough was made possible, thanks to advanced super-resolution imaging techniques. It fundamentally changed our understanding of excitatory synaptic architecture and paved the way for a brand-new area of research. In this Progressions article, the primary investigators of the nanoscale organization of synapses have come together to chronicle the tale of their discovery. We recount the initial inquiry that prompted our research, the preceding studies that inspired our work, the technical obstacles that were encountered, and the breakthroughs that were made in the subsequent decade in the realm of nanoscale synaptic transmission. We review the new discoveries made possible by the democratization of super-resolution imaging techniques in the field of excitatory synaptic physiology and architecture, first by the extension to other glutamate receptors and to presynaptic proteins and then by the notion of trans-synaptic organization. After describing the organizational modifications occurring in various pathologies, we discuss briefly the latest technical developments made possible by super-resolution imaging and emerging concepts in synaptic physiology.
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Affiliation(s)
- Yuko Fukata
- Division of Molecular and Cellular Pharmacology, Nagoya University Graduate School of Medicine, Nagoya, Aichi 466-8550, Japan
- Division of Membrane Physiology, Department of Molecular and Cellular Physiology, National Institute for Physiological Sciences, National Institutes of Natural Sciences, Okazaki, Aichi 444-8787, Japan
| | - Masaki Fukata
- Division of Membrane Physiology, Department of Molecular and Cellular Physiology, National Institute for Physiological Sciences, National Institutes of Natural Sciences, Okazaki, Aichi 444-8787, Japan
- Division of Neuropharmacology, Nagoya University Graduate School of Medicine, Nagoya, Aichi 466-8550, Japan
- Department of Physiological Sciences, School of Life Science, SOKENDAI (The Graduate University for Advanced Studies), Okazaki, Aichi 444-8585, Japan
| | - Harold D MacGillavry
- Division of Cell Biology, Neurobiology and Biophysics, Department of Biology, Faculty of Science, Utrecht University, Utrecht 3584 CH, The Netherlands
| | - Deepak Nair
- Centre for Neuroscience, Indian Institute of Science, Bangalore 560012, Karnataka, India
| | - Eric Hosy
- Interdisciplinary Institute for Neuroscience, University of Bordeaux, CNRS UMR5297, Bordeaux F-33000, France
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4
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Kaizuka T, Takumi T. Alteration of synaptic protein composition during developmental synapse maturation. Eur J Neurosci 2024; 59:2894-2914. [PMID: 38571321 DOI: 10.1111/ejn.16304] [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: 05/01/2023] [Revised: 01/02/2024] [Accepted: 02/07/2024] [Indexed: 04/05/2024]
Abstract
The postsynaptic density (PSD) is a collection of specialized proteins assembled beneath the postsynaptic membrane of dendritic spines. The PSD proteome comprises ~1000 proteins, including neurotransmitter receptors, scaffolding proteins and signalling enzymes. Many of these proteins have essential roles in synaptic function and plasticity. During brain development, changes are observed in synapse density and in the stability and shape of spines, reflecting the underlying molecular maturation of synapses. Synaptic protein composition changes in terms of protein abundance and the assembly of protein complexes, supercomplexes and the physical organization of the PSD. Here, we summarize the developmental alterations of postsynaptic protein composition during synapse maturation. We describe major PSD proteins involved in postsynaptic signalling that regulates synaptic plasticity and discuss the effect of altered expression of these proteins during development. We consider the abnormality of synaptic profiles and synaptic protein composition in the brain in neurodevelopmental disorders such as autism spectrum disorders. We also explain differences in synapse development between rodents and primates in terms of synaptic profiles and protein composition. Finally, we introduce recent findings related to synaptic diversity and nanoarchitecture and discuss their impact on future research. Synaptic protein composition can be considered a major determinant and marker of synapse maturation in normality and disease.
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Affiliation(s)
- Takeshi Kaizuka
- Department of Physiology and Cell Biology, Kobe University School of Medicine, Kobe, Japan
- Centre for Clinical Brain Sciences, University of Edinburgh, Edinburgh, UK
| | - Toru Takumi
- Department of Physiology and Cell Biology, Kobe University School of Medicine, Kobe, Japan
- RIKEN Center for Biosystems Dynamics Research, Kobe, Japan
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5
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Barti B, Dudok B, Kenesei K, Zöldi M, Miczán V, Balla GY, Zala D, Tasso M, Sagheddu C, Kisfali M, Tóth B, Ledri M, Vizi ES, Melis M, Barna L, Lenkei Z, Soltész I, Katona I. Presynaptic nanoscale components of retrograde synaptic signaling. SCIENCE ADVANCES 2024; 10:eado0077. [PMID: 38809980 PMCID: PMC11135421 DOI: 10.1126/sciadv.ado0077] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/11/2024] [Accepted: 04/23/2024] [Indexed: 05/31/2024]
Abstract
While our understanding of the nanoscale architecture of anterograde synaptic transmission is rapidly expanding, the qualitative and quantitative molecular principles underlying distinct mechanisms of retrograde synaptic communication remain elusive. We show that a particular form of tonic cannabinoid signaling is essential for setting target cell-dependent synaptic variability. It does not require the activity of the two major endocannabinoid-producing enzymes. Instead, by developing a workflow for physiological, anatomical, and molecular measurements at the same unitary synapse, we demonstrate that the nanoscale stoichiometric ratio of type 1 cannabinoid receptors (CB1Rs) to the release machinery is sufficient to predict synapse-specific release probability. Accordingly, selective decrease of extrasynaptic CB1Rs does not affect synaptic transmission, whereas in vivo exposure to the phytocannabinoid Δ9-tetrahydrocannabinol disrupts the intrasynaptic nanoscale stoichiometry and reduces synaptic variability. These findings imply that synapses leverage the nanoscale stoichiometry of presynaptic receptor coupling to the release machinery to establish synaptic strength in a target cell-dependent manner.
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Affiliation(s)
- Benjámin Barti
- Department of Psychological and Brain Sciences, Indiana University Bloomington, 702 N Walnut Grove Ave, Bloomington, IN 47405-2204, USA
- Molecular Neurobiology Research Group, HUN-REN Institute of Experimental Medicine, Szigony st 43, H-1083 Budapest, Hungary
- School of Ph.D. Studies, Semmelweis University, Üllői st 26, H-1085 Budapest, Hungary
| | - Barna Dudok
- Molecular Neurobiology Research Group, HUN-REN Institute of Experimental Medicine, Szigony st 43, H-1083 Budapest, Hungary
- Departments of Neurology and Neuroscience, Baylor College of Medicine, 1 Baylor Plz, Houston, TX 77030, USA
- Department of Neurosurgery, Stanford University, 450 Jane Stanford Way, Stanford, CA 94305, USA
| | - Kata Kenesei
- Molecular Neurobiology Research Group, HUN-REN Institute of Experimental Medicine, Szigony st 43, H-1083 Budapest, Hungary
| | - Miklós Zöldi
- Department of Psychological and Brain Sciences, Indiana University Bloomington, 702 N Walnut Grove Ave, Bloomington, IN 47405-2204, USA
- Molecular Neurobiology Research Group, HUN-REN Institute of Experimental Medicine, Szigony st 43, H-1083 Budapest, Hungary
- School of Ph.D. Studies, Semmelweis University, Üllői st 26, H-1085 Budapest, Hungary
| | - Vivien Miczán
- Molecular Neurobiology Research Group, HUN-REN Institute of Experimental Medicine, Szigony st 43, H-1083 Budapest, Hungary
- Synthetic and Systems Biology Unit, HUN-REN Biological Research Center, Temesvári krt. 62, H-6726 Szeged, Hungary
| | - Gyula Y. Balla
- Molecular Neurobiology Research Group, HUN-REN Institute of Experimental Medicine, Szigony st 43, H-1083 Budapest, Hungary
- School of Ph.D. Studies, Semmelweis University, Üllői st 26, H-1085 Budapest, Hungary
- Translational Behavioral Neuroscience Research Group, HUN-REN Institute of Experimental Medicine, Szigony st 43, H-1083 Budapest, Hungary
| | - Diana Zala
- Université Paris Cité, INSERM, Institute of Psychiatry and Neurosciences of Paris, F-75014 Paris, France
| | - Mariana Tasso
- Institute of Nanosystems, School of Bio and Nanotechnologies, National University of San Martín - CONICET, 25 de Mayo Ave., 1021 San Martín, Argentina
| | - Claudia Sagheddu
- Department of Biomedical Sciences, University of Cagliari, Cittadella Universitaria di Monserrato, Monserrato, 09042 Cagliari, Italy
| | - Máté Kisfali
- Molecular Neurobiology Research Group, HUN-REN Institute of Experimental Medicine, Szigony st 43, H-1083 Budapest, Hungary
- BiTrial Ltd., Tállya st 23, H-1121 Budapest, Hungary
| | - Blanka Tóth
- Department of Inorganic and Analytical Chemistry, Budapest University of Technology and Economics, Szt. Gellért square 4, H-1111 Budapest, Hungary
- Department of Molecular Biology, Semmelweis University, Üllői st 26, H-1085 Budapest, Hungary
| | - Marco Ledri
- Molecular Neurobiology Research Group, HUN-REN Institute of Experimental Medicine, Szigony st 43, H-1083 Budapest, Hungary
- Epilepsy Center, Department of Clinical Sciences, Faculty of Medicine, Lund University, Sölvegatan 17, BMC A11, 221 84 Lund, Sweden
| | - E. Sylvester Vizi
- Molecular Pharmacology Research Group, HUN-REN Institute of Experimental Medicine, Szigony st 43, H-1083 Budapest, Hungary
| | - Miriam Melis
- Department of Biomedical Sciences, University of Cagliari, Cittadella Universitaria di Monserrato, Monserrato, 09042 Cagliari, Italy
| | - László Barna
- Department of Psychological and Brain Sciences, Indiana University Bloomington, 702 N Walnut Grove Ave, Bloomington, IN 47405-2204, USA
| | - Zsolt Lenkei
- Université Paris Cité, INSERM, Institute of Psychiatry and Neurosciences of Paris, F-75014 Paris, France
| | - Iván Soltész
- Department of Neurosurgery, Stanford University, 450 Jane Stanford Way, Stanford, CA 94305, USA
| | - István Katona
- Department of Psychological and Brain Sciences, Indiana University Bloomington, 702 N Walnut Grove Ave, Bloomington, IN 47405-2204, USA
- Molecular Neurobiology Research Group, HUN-REN Institute of Experimental Medicine, Szigony st 43, H-1083 Budapest, Hungary
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6
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Myeong J, Stunault MI, Klyachko VA, Ashrafi G. Metabolic regulation of single synaptic vesicle exo- and endocytosis in hippocampal synapses. Cell Rep 2024; 43:114218. [PMID: 38758651 DOI: 10.1016/j.celrep.2024.114218] [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: 11/13/2023] [Revised: 02/26/2024] [Accepted: 04/25/2024] [Indexed: 05/19/2024] Open
Abstract
Glucose has long been considered a primary energy source for synaptic function. However, it remains unclear to what extent alternative fuels, such as lactate/pyruvate, contribute to powering synaptic transmission. By detecting individual release events in hippocampal synapses, we find that mitochondrial ATP production regulates basal vesicle release probability and release location within the active zone (AZ), evoked by single action potentials. Mitochondrial inhibition shifts vesicle release closer to the AZ center and alters the efficiency of vesicle retrieval by increasing the occurrence of ultrafast endocytosis. Furthermore, we uncover that terminals can use oxidative fuels to maintain the vesicle cycle during trains of activity. Mitochondria are sparsely distributed along hippocampal axons, and we find that terminals containing mitochondria display enhanced vesicle release and reuptake during high-frequency trains. Our findings suggest that mitochondria not only regulate several fundamental features of synaptic transmission but may also contribute to modulation of short-term synaptic plasticity.
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Affiliation(s)
- Jongyun Myeong
- Department of Cell Biology and Physiology, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Marion I Stunault
- Department of Cell Biology and Physiology, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Vitaly A Klyachko
- Department of Cell Biology and Physiology, Washington University School of Medicine, St. Louis, MO 63110, USA.
| | - Ghazaleh Ashrafi
- Department of Cell Biology and Physiology, Washington University School of Medicine, St. Louis, MO 63110, USA; Needleman Center for Neurometabolism and Axonal Therapeutics, Washington University School of Medicine, St. Louis, MO 63110, USA.
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7
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Cuhadar U, Calzado-Reyes L, Pascual-Caro C, Aberra AS, Ritzau-Jost A, Aggarwal A, Ibata K, Podgorski K, Yuzaki M, Geis C, Hallerman S, Hoppa MB, de Juan-Sanz J. Activity-driven synaptic translocation of LGI1 controls excitatory neurotransmission. Cell Rep 2024; 43:114186. [PMID: 38700985 PMCID: PMC11156761 DOI: 10.1016/j.celrep.2024.114186] [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: 06/28/2022] [Revised: 12/14/2023] [Accepted: 04/17/2024] [Indexed: 05/05/2024] Open
Abstract
The fine control of synaptic function requires robust trans-synaptic molecular interactions. However, it remains poorly understood how trans-synaptic bridges change to reflect the functional states of the synapse. Here, we develop optical tools to visualize in firing synapses the molecular behavior of two trans-synaptic proteins, LGI1 and ADAM23, and find that neuronal activity acutely rearranges their abundance at the synaptic cleft. Surprisingly, synaptic LGI1 is primarily not secreted, as described elsewhere, but exo- and endocytosed through its interaction with ADAM23. Activity-driven translocation of LGI1 facilitates the formation of trans-synaptic connections proportionally to the history of activity of the synapse, adjusting excitatory transmission to synaptic firing rates. Accordingly, we find that patient-derived autoantibodies against LGI1 reduce its surface fraction and cause increased glutamate release. Our findings suggest that LGI1 abundance at the synaptic cleft can be acutely remodeled and serves as a critical control point for synaptic function.
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Affiliation(s)
- Ulku Cuhadar
- Sorbonne Université, Institut du Cerveau - Paris Brain Institute - ICM, Inserm, CNRS, APHP, Hôpital de la Pitié Salpêtrière, 75013 Paris, France
| | - Lorenzo Calzado-Reyes
- Sorbonne Université, Institut du Cerveau - Paris Brain Institute - ICM, Inserm, CNRS, APHP, Hôpital de la Pitié Salpêtrière, 75013 Paris, France
| | - Carlos Pascual-Caro
- Sorbonne Université, Institut du Cerveau - Paris Brain Institute - ICM, Inserm, CNRS, APHP, Hôpital de la Pitié Salpêtrière, 75013 Paris, France
| | - Aman S Aberra
- Department of Biology, Dartmouth College, Hanover, NH 03755, USA
| | - Andreas Ritzau-Jost
- Carl-Ludwig-Institute of Physiology, Faculty of Medicine, Leipzig University, 04317 Leipzig, Germany
| | - Abhi Aggarwal
- Allen Institute for Brain Science, Seattle, WA 98109, USA
| | - Keiji Ibata
- Department of Neurophysiology, Keio University, Tokyo 160-8582, Japan
| | | | - Michisuke Yuzaki
- Department of Neurophysiology, Keio University, Tokyo 160-8582, Japan
| | - Christian Geis
- Department of Neurology, Section Translational Neuroimmunology, Jena University Hospital, 07747 Jena, Germany
| | - Stefan Hallerman
- Carl-Ludwig-Institute of Physiology, Faculty of Medicine, Leipzig University, 04317 Leipzig, Germany
| | - Michael B Hoppa
- Department of Biology, Dartmouth College, Hanover, NH 03755, USA
| | - Jaime de Juan-Sanz
- Sorbonne Université, Institut du Cerveau - Paris Brain Institute - ICM, Inserm, CNRS, APHP, Hôpital de la Pitié Salpêtrière, 75013 Paris, France.
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8
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Zhu S, Shen Z, Wu X, Han W, Jia B, Lu W, Zhang M. Demixing is a default process for biological condensates formed via phase separation. Science 2024; 384:920-928. [PMID: 38781377 DOI: 10.1126/science.adj7066] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2023] [Accepted: 04/15/2024] [Indexed: 05/25/2024]
Abstract
Excitatory and inhibitory synapses do not overlap even when formed on one submicron-sized dendritic protrusion. How excitatory and inhibitory postsynaptic cytomatrices or densities (e/iPSDs) are segregated is not understood. Broadly, why membraneless organelles are naturally segregated in cellular subcompartments is unclear. Using biochemical reconstitutions in vitro and in cells, we demonstrate that ePSDs and iPSDs spontaneously segregate into distinct condensed molecular assemblies through phase separation. Tagging iPSD scaffold gephyrin with a PSD-95 intrabody (dissociation constant ~4 nM) leads to mistargeting of gephyrin to ePSD condensates. Unexpectedly, formation of iPSD condensates forces the intrabody-tagged gephyrin out of ePSD condensates. Thus, instead of diffusion-governed spontaneous mixing, demixing is a default process for biomolecules in condensates. Phase separation can generate biomolecular compartmentalization specificities that cannot occur in dilute solutions.
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Affiliation(s)
- Shihan Zhu
- Division of Life Science, Hong Kong University of Science and Technology, Hong Kong, China
- School of Life Sciences, Southern University of Science and Technology, Shenzhen 518055, China
| | - Zeyu Shen
- Division of Life Science, Hong Kong University of Science and Technology, Hong Kong, China
- School of Life Sciences, Southern University of Science and Technology, Shenzhen 518055, China
| | - Xiandeng Wu
- Division of Life Science, Hong Kong University of Science and Technology, Hong Kong, China
| | - Wenyan Han
- Synapse and Neural Circuit Research Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20824, USA
| | - Bowen Jia
- Division of Life Science, Hong Kong University of Science and Technology, Hong Kong, China
| | - Wei Lu
- Synapse and Neural Circuit Research Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20824, USA
| | - Mingjie Zhang
- School of Life Sciences, Southern University of Science and Technology, Shenzhen 518055, China
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9
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Zhang H, Lei M, Zhang Y, Li H, He Z, Xie S, Zhu L, Wang S, Liu J, Li Y, Lu Y, Ma C. Phosphorylation of Doc2 by EphB2 modulates Munc13-mediated SNARE complex assembly and neurotransmitter release. SCIENCE ADVANCES 2024; 10:eadi7024. [PMID: 38758791 PMCID: PMC11100570 DOI: 10.1126/sciadv.adi7024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/12/2023] [Accepted: 04/12/2024] [Indexed: 05/19/2024]
Abstract
At the synapse, presynaptic neurotransmitter release is tightly controlled by release machinery, involving the soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) proteins and Munc13. The Ca2+ sensor Doc2 cooperates with Munc13 to regulate neurotransmitter release, but the underlying mechanisms remain unclear. In our study, we have characterized the binding mode between Doc2 and Munc13 and found that Doc2 originally occludes Munc13 to inhibit SNARE complex assembly. Moreover, our investigation unveiled that EphB2, a presynaptic adhesion molecule (SAM) with inherent tyrosine kinase functionality, exhibits the capacity to phosphorylate Doc2. This phosphorylation attenuates Doc2 block on Munc13 to promote SNARE complex assembly, which functionally induces spontaneous release and synaptic augmentation. Consistently, application of a Doc2 peptide that interrupts Doc2-Munc13 interplay impairs excitatory synaptic transmission and leads to dysfunction in spatial learning and memory. These data provide evidence that SAMs modulate neurotransmitter release by controlling SNARE complex assembly.
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Affiliation(s)
- Hong Zhang
- Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, 430074 Wuhan, China
| | - Mengshi Lei
- Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, 430074 Wuhan, China
| | - Yu Zhang
- Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, 430074 Wuhan, China
| | - Hao Li
- Institute for Brain Research, Wuhan Center of Brain Science, Huazhong University of Science and Technology, Wuhan 430030, China
- Department of Pathophysiology, School of Basic Medicine and Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Zhen He
- Department of Pathogen Biology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, 430030 Wuhan, China
| | - Sheng Xie
- Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, 430074 Wuhan, China
| | - Le Zhu
- Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, 430074 Wuhan, China
| | - Shen Wang
- Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, 430074 Wuhan, China
| | - Jianfeng Liu
- Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, 430074 Wuhan, China
| | - Yan Li
- Department of Pathogen Biology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, 430030 Wuhan, China
| | - Youming Lu
- Institute for Brain Research, Wuhan Center of Brain Science, Huazhong University of Science and Technology, Wuhan 430030, China
- Department of Pathophysiology, School of Basic Medicine and Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Cong Ma
- Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, 430074 Wuhan, China
- Institute for Brain Research, Wuhan Center of Brain Science, Huazhong University of Science and Technology, Wuhan 430030, China
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10
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Jones G, Akter Y, Shifflett V, Hruska M. Nanoscale analysis of functionally diverse glutamatergic synapses in the neocortex reveals input and layer-specific organization. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.05.01.592008. [PMID: 38746319 PMCID: PMC11092571 DOI: 10.1101/2024.05.01.592008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2024]
Abstract
Discovery of synaptic nanostructures suggests a molecular logic for the flexibility of synaptic function. We still have little understanding of how functionally diverse synapses in the brain organize their nanoarchitecture due to challenges associated with super-resolution imaging in complex brain tissue. Here, we characterized single-domain camelid nanobodies for the 3D quantitative multiplex imaging of synaptic nano-organization in 6 µm brain cryosections using STED nanoscopy. We focused on thalamocortical (TC) and corticocortical (CC) synapses along the apical-basal axis of layer 5 pyramidal neurons as models of functionally diverse glutamatergic synapses in the brain. Spines receiving TC input were larger than CC spines in all layers examined. However, TC synapses on apical and basal dendrites conformed to different organizational principles. TC afferents on apical dendrites frequently contacted spines with multiple aligned PSD-95/Bassoon nanomodules, which are larger. TC spines on basal dendrites contained mostly one aligned PSD-95/Bassoon nanocluster. However, PSD-95 nanoclusters were larger and scaled with spine volume. The nano-organization of CC synapses did not change across cortical layers. These results highlight striking nanoscale diversity of functionally distinct glutamatergic synapses, relying on afferent input and sub-cellular localization of individual synaptic connections.
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11
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Ralowicz AJ, Hokeness S, Hoppa MB. Frequency of Spontaneous Neurotransmission at Individual Boutons Corresponds to the Size of the Readily Releasable Pool of Vesicles. J Neurosci 2024; 44:e1253232024. [PMID: 38383495 PMCID: PMC11063817 DOI: 10.1523/jneurosci.1253-23.2024] [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: 07/06/2023] [Revised: 02/09/2024] [Accepted: 02/13/2024] [Indexed: 02/23/2024] Open
Abstract
Synapses maintain two forms of neurotransmitter release to support communication in the brain. First, evoked neurotransmitter release is triggered by the invasion of an action potential (AP) across en passant boutons that form along axons. The probability of evoked release (Pr) varies substantially across boutons, even within a single axon. Such heterogeneity is the result of differences in the probability of a single synaptic vesicle (SV) fusing (Pv) and in the number of vesicles available for immediate release, known as the readily releasable pool (RRP). Spontaneous release (also known as a mini) is an important form of neurotransmission that occurs in the absence of APs. Because it cannot be triggered with electrical stimulation, much less is known about potential heterogeneity in the frequency of spontaneous release between boutons. We utilized a photostable and bright fluorescent indicator of glutamate release (iGluSnFR3) to quantify both spontaneous and evoked release at individual glutamatergic boutons. We found that the rate of spontaneous release is quite heterogenous at the level of individual boutons. Interestingly, when measuring both evoked and spontaneous release at single synapses, we found that boutons with the highest rates of spontaneous release also displayed the largest evoked responses. Using a new optical method to measure RRP at individual boutons, we found that this heterogeneity in spontaneous release was strongly correlated with the size of the RRP, but not related to Pv. We conclude that the RRP is a critical and dynamic aspect of synaptic strength that contributes to both evoked and spontaneous vesicle release.
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Affiliation(s)
- Amelia J Ralowicz
- Department of Biology, Dartmouth College, Hanover, New Hampshire 03755
| | - Sasipha Hokeness
- Department of Biology, Dartmouth College, Hanover, New Hampshire 03755
| | - Michael B Hoppa
- Department of Biology, Dartmouth College, Hanover, New Hampshire 03755
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12
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Stockwell I, Watson JF, Greger IH. Tuning synaptic strength by regulation of AMPA glutamate receptor localization. Bioessays 2024:e2400006. [PMID: 38693811 DOI: 10.1002/bies.202400006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2024] [Revised: 04/19/2024] [Accepted: 04/23/2024] [Indexed: 05/03/2024]
Abstract
Long-term potentiation (LTP) of excitatory synapses is a leading model to explain the concept of information storage in the brain. Multiple mechanisms contribute to LTP, but central amongst them is an increased sensitivity of the postsynaptic membrane to neurotransmitter release. This sensitivity is predominantly determined by the abundance and localization of AMPA-type glutamate receptors (AMPARs). A combination of AMPAR structural data, super-resolution imaging of excitatory synapses, and an abundance of electrophysiological studies are providing an ever-clearer picture of how AMPARs are recruited and organized at synaptic junctions. Here, we review the latest insights into this process, and discuss how both cytoplasmic and extracellular receptor elements cooperate to tune the AMPAR response at the hippocampal CA1 synapse.
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Affiliation(s)
- Imogen Stockwell
- Neurobiology Division, MRC Laboratory of Molecular Biology, Cambridge, UK
| | - Jake F Watson
- Institute of Science and Technology, Technology (IST) Austria, Klosterneuburg, Austria
| | - Ingo H Greger
- Neurobiology Division, MRC Laboratory of Molecular Biology, Cambridge, UK
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13
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Xu N, Cao R, Chen SY, Gou XZ, Wang B, Luo HM, Gao F, Tang AH. Structural and functional reorganization of inhibitory synapses by activity-dependent cleavage of neuroligin-2. Proc Natl Acad Sci U S A 2024; 121:e2314541121. [PMID: 38657049 PMCID: PMC11067042 DOI: 10.1073/pnas.2314541121] [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: 08/23/2023] [Accepted: 03/21/2024] [Indexed: 04/26/2024] Open
Abstract
Recent evidence has demonstrated that the transsynaptic nanoscale organization of synaptic proteins plays a crucial role in regulating synaptic strength in excitatory synapses. However, the molecular mechanism underlying this transsynaptic nanostructure in inhibitory synapses still remains unclear and its impact on synapse function in physiological or pathological contexts has not been demonstrated. In this study, we utilized an engineered proteolysis technique to investigate the effects of acute cleavage of neuroligin-2 (NL2) on synaptic transmission. Our results show that the rapid cleavage of NL2 led to impaired synaptic transmission by reducing both neurotransmitter release probability and quantum size. These changes were attributed to the dispersion of RIM1/2 and GABAA receptors and a weakened spatial alignment between them at the subsynaptic scale, as observed through superresolution imaging and model simulations. Importantly, we found that endogenous NL2 undergoes rapid MMP9-dependent cleavage during epileptic activities, which further exacerbates the decrease in inhibitory transmission. Overall, our study demonstrates the significant impact of nanoscale structural reorganization on inhibitory transmission and unveils ongoing modulation of mature GABAergic synapses through active cleavage of NL2 in response to hyperactivity.
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Affiliation(s)
- Na Xu
- Department of Neurology, Institute on Aging and Brain Disorders, The First Affiliated Hospital, University of Science and Technology of China, Luyang District, Hefei, Anhui 230001, China
- Anhui Province Key Laboratory of Biomedical Imaging and Intelligent Processing, Institute of Artificial Intelligence, Hefei Comprehensive National Science Center, 5089 Wangjiang West Road, Gaoxin District, Hefei, Anhui 230088, China
- Ministry of Education Key Laboratory for Membrane-less Organelles and Cellular Dynamics, Division of Life Sciences and Medicine, University of Science and Technology of China, Shushan District, Hefei, Anhui 230027, China
| | - Ran Cao
- Anhui Province Key Laboratory of Biomedical Imaging and Intelligent Processing, Institute of Artificial Intelligence, Hefei Comprehensive National Science Center, 5089 Wangjiang West Road, Gaoxin District, Hefei, Anhui 230088, China
- Hefei National Laboratory for Physical Sciences at the Microscale, Division of Life Sciences and Medicine, University of Science and Technology of China, Baohe District, Hefei, Anhui 230026, China
| | - Si-Yu Chen
- Ministry of Education Key Laboratory for Membrane-less Organelles and Cellular Dynamics, Division of Life Sciences and Medicine, University of Science and Technology of China, Shushan District, Hefei, Anhui 230027, China
- Hefei National Laboratory for Physical Sciences at the Microscale, Division of Life Sciences and Medicine, University of Science and Technology of China, Baohe District, Hefei, Anhui 230026, China
| | - Xu-Zhuo Gou
- Anhui Province Key Laboratory of Biomedical Imaging and Intelligent Processing, Institute of Artificial Intelligence, Hefei Comprehensive National Science Center, 5089 Wangjiang West Road, Gaoxin District, Hefei, Anhui 230088, China
- Ministry of Education Key Laboratory for Membrane-less Organelles and Cellular Dynamics, Division of Life Sciences and Medicine, University of Science and Technology of China, Shushan District, Hefei, Anhui 230027, China
- Hefei National Laboratory for Physical Sciences at the Microscale, Division of Life Sciences and Medicine, University of Science and Technology of China, Baohe District, Hefei, Anhui 230026, China
| | - Bin Wang
- Anhui Province Key Laboratory of Biomedical Imaging and Intelligent Processing, Institute of Artificial Intelligence, Hefei Comprehensive National Science Center, 5089 Wangjiang West Road, Gaoxin District, Hefei, Anhui 230088, China
- School of Life Sciences, Zhengzhou University, Zhengzhou, Henan 450001, China
| | - Hong-Mei Luo
- Anhui Province Key Laboratory of Biomedical Imaging and Intelligent Processing, Institute of Artificial Intelligence, Hefei Comprehensive National Science Center, 5089 Wangjiang West Road, Gaoxin District, Hefei, Anhui 230088, China
- Ministry of Education Key Laboratory for Membrane-less Organelles and Cellular Dynamics, Division of Life Sciences and Medicine, University of Science and Technology of China, Shushan District, Hefei, Anhui 230027, China
| | - Feng Gao
- Department of Neurology, Institute on Aging and Brain Disorders, The First Affiliated Hospital, University of Science and Technology of China, Luyang District, Hefei, Anhui 230001, China
| | - Ai-Hui Tang
- Department of Neurology, Institute on Aging and Brain Disorders, The First Affiliated Hospital, University of Science and Technology of China, Luyang District, Hefei, Anhui 230001, China
- Anhui Province Key Laboratory of Biomedical Imaging and Intelligent Processing, Institute of Artificial Intelligence, Hefei Comprehensive National Science Center, 5089 Wangjiang West Road, Gaoxin District, Hefei, Anhui 230088, China
- Ministry of Education Key Laboratory for Membrane-less Organelles and Cellular Dynamics, Division of Life Sciences and Medicine, University of Science and Technology of China, Shushan District, Hefei, Anhui 230027, China
- Hefei National Laboratory for Physical Sciences at the Microscale, Division of Life Sciences and Medicine, University of Science and Technology of China, Baohe District, Hefei, Anhui 230026, China
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14
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Dharmasri PA, Levy AD, Blanpied TA. Differential nanoscale organization of excitatory synapses onto excitatory vs. inhibitory neurons. Proc Natl Acad Sci U S A 2024; 121:e2315379121. [PMID: 38625946 PMCID: PMC11047112 DOI: 10.1073/pnas.2315379121] [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: 09/18/2023] [Accepted: 03/14/2024] [Indexed: 04/18/2024] Open
Abstract
A key feature of excitatory synapses is the existence of subsynaptic protein nanoclusters (NCs) whose precise alignment across the cleft in a transsynaptic nanocolumn influences the strength of synaptic transmission. However, whether nanocolumn properties vary between excitatory synapses functioning in different cellular contexts is unknown. We used a combination of confocal and DNA-PAINT super-resolution microscopy to directly compare the organization of shared scaffold proteins at two important excitatory synapses-those forming onto excitatory principal neurons (Ex→Ex synapses) and those forming onto parvalbumin-expressing interneurons (Ex→PV synapses). As in Ex→Ex synapses, we find that in Ex→PV synapses, presynaptic Munc13-1 and postsynaptic PSD-95 both form NCs that demonstrate alignment, underscoring synaptic nanostructure and the transsynaptic nanocolumn as conserved organizational principles of excitatory synapses. Despite the general conservation of these features, we observed specific differences in the characteristics of pre- and postsynaptic Ex→PV nanostructure. Ex→PV synapses contained larger PSDs with fewer PSD-95 NCs when accounting for size than Ex→Ex synapses. Furthermore, the PSD-95 NCs were larger and denser. The identity of the postsynaptic cell was also represented in Munc13-1 organization, as Ex→PV synapses hosted larger Munc13-1 puncta that contained less dense but larger and more numerous Munc13-1 NCs. Moreover, we measured the spatial variability of transsynaptic alignment in these synapse types, revealing protein alignment in Ex→PV synapses over a distinct range of distances compared to Ex→Ex synapses. We conclude that while general principles of nanostructure and alignment are shared, cell-specific elements of nanodomain organization likely contribute to functional diversity of excitatory synapses.
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Affiliation(s)
- Poorna A. Dharmasri
- Department of Physiology, University of Maryland School of Medicine, Baltimore, MD21201
- Program in Neuroscience, University of Maryland School of Medicine, Baltimore, MD21201
- University of Maryland-Medicine Institute of Neuroscience Discovery, University of Maryland School of Medicine, Baltimore, MD21201
| | - Aaron D. Levy
- Department of Physiology, University of Maryland School of Medicine, Baltimore, MD21201
- University of Maryland-Medicine Institute of Neuroscience Discovery, University of Maryland School of Medicine, Baltimore, MD21201
| | - Thomas A. Blanpied
- Department of Physiology, University of Maryland School of Medicine, Baltimore, MD21201
- Program in Neuroscience, University of Maryland School of Medicine, Baltimore, MD21201
- University of Maryland-Medicine Institute of Neuroscience Discovery, University of Maryland School of Medicine, Baltimore, MD21201
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15
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Delling JP, Bauer HF, Gerlach-Arbeiter S, Schön M, Jacob C, Wagner J, Pedro MT, Knöll B, Boeckers TM. Combined expansion and STED microscopy reveals altered fingerprints of postsynaptic nanostructure across brain regions in ASD-related SHANK3-deficiency. Mol Psychiatry 2024:10.1038/s41380-024-02559-9. [PMID: 38649753 DOI: 10.1038/s41380-024-02559-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/05/2023] [Revised: 04/02/2024] [Accepted: 04/08/2024] [Indexed: 04/25/2024]
Abstract
Synaptic dysfunction is a key feature of SHANK-associated disorders such as autism spectrum disorder, schizophrenia, and Phelan-McDermid syndrome. Since detailed knowledge of their effect on synaptic nanostructure remains limited, we aimed to investigate such alterations in ex11|SH3 SHANK3-KO mice combining expansion and STED microscopy. This enabled high-resolution imaging of mosaic-like arrangements formed by synaptic proteins in both human and murine brain tissue. We found distinct shape-profiles as fingerprints of the murine postsynaptic scaffold across brain regions and genotypes, as well as alterations in the spatial and molecular organization of subsynaptic domains under SHANK3-deficient conditions. These results provide insights into synaptic nanostructure in situ and advance our understanding of molecular mechanisms underlying synaptic dysfunction in neuropsychiatric disorders.
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Affiliation(s)
- Jan Philipp Delling
- Institute of Anatomy and Cell Biology, Ulm University, Ulm, 89081, Germany.
- Max Planck Institute of Psychiatry, Munich, 80804, Germany.
| | | | | | - Michael Schön
- Institute of Anatomy and Cell Biology, Ulm University, Ulm, 89081, Germany
| | - Christian Jacob
- Institute of Anatomy and Cell Biology, Ulm University, Ulm, 89081, Germany
| | - Jan Wagner
- Department of Neurology, Ulm University, Ulm, 89081, Germany
| | | | - Bernd Knöll
- Institute of Neurobiochemistry, Ulm University, Ulm, 89081, Germany
| | - Tobias M Boeckers
- Institute of Anatomy and Cell Biology, Ulm University, Ulm, 89081, Germany.
- Ulm Site, DZNE, Ulm, 89081, Germany.
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16
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Chen Y, Liu S, Jacobi AA, Jeng G, Ulrich JD, Stein IS, Patriarchi T, Hell JW. Rapid sequential clustering of NMDARs, CaMKII, and AMPARs upon activation of NMDARs at developing synapses. Front Synaptic Neurosci 2024; 16:1291262. [PMID: 38660466 PMCID: PMC11039796 DOI: 10.3389/fnsyn.2024.1291262] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2023] [Accepted: 03/22/2024] [Indexed: 04/26/2024] Open
Abstract
Rapid, synapse-specific neurotransmission requires the precise alignment of presynaptic neurotransmitter release and postsynaptic receptors. How postsynaptic glutamate receptor accumulation is induced during maturation is not well understood. We find that in cultures of dissociated hippocampal neurons at 11 days in vitro (DIV) numerous synaptic contacts already exhibit pronounced accumulations of the pre- and postsynaptic markers synaptotagmin, synaptophysin, synapsin, bassoon, VGluT1, PSD-95, and Shank. The presence of an initial set of AMPARs and NMDARs is indicated by miniature excitatory postsynaptic currents (mEPSCs). However, AMPAR and NMDAR immunostainings reveal rather smooth distributions throughout dendrites and synaptic enrichment is not obvious. We found that brief periods of Ca2+ influx through NMDARs induced a surprisingly rapid accumulation of NMDARs within 1 min, followed by accumulation of CaMKII and then AMPARs within 2-5 min. Postsynaptic clustering of NMDARs and AMPARs was paralleled by an increase in their mEPSC amplitudes. A peptide that blocked the interaction of NMDAR subunits with PSD-95 prevented the NMDAR clustering. NMDAR clustering persisted for 3 days indicating that brief periods of elevated glutamate fosters permanent accumulation of NMDARs at postsynaptic sites in maturing synapses. These data support the model that strong glutamatergic stimulation of immature glutamatergic synapses results in a fast and substantial increase in postsynaptic NMDAR content that required NMDAR binding to PSD-95 or its homologues and is followed by recruitment of CaMKII and subsequently AMPARs.
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Affiliation(s)
- Yucui Chen
- Department of Pharmacology, University of Iowa, Iowa City, IA, United States
| | - Shangming Liu
- Department of Pharmacology, University of California, Davis, Davis, CA, United States
| | - Ariel A. Jacobi
- Department of Pharmacology, University of California, Davis, Davis, CA, United States
| | - Grace Jeng
- Department of Pharmacology, University of California, Davis, Davis, CA, United States
| | - Jason D. Ulrich
- Department of Pharmacology, University of Iowa, Iowa City, IA, United States
| | - Ivar S. Stein
- Department of Pharmacology, University of Iowa, Iowa City, IA, United States
- Department of Pharmacology, University of California, Davis, Davis, CA, United States
| | - Tommaso Patriarchi
- Department of Pharmacology, University of California, Davis, Davis, CA, United States
| | - Johannes W. Hell
- Department of Pharmacology, University of Iowa, Iowa City, IA, United States
- Department of Pharmacology, University of California, Davis, Davis, CA, United States
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17
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Sun C. Single-Molecule-Resolution Approaches in Synaptic Biology. J Phys Chem B 2024; 128:3061-3068. [PMID: 38513216 DOI: 10.1021/acs.jpcb.3c08026] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/23/2024]
Abstract
Synapses between neurons are the primary loci for information transfer and storage in the brain. An individual neuron, alone, can make over 10000 synaptic contacts. It is, however, not easy to investigate what goes on locally within a synapse because many synaptic compartments are only a few hundred nanometers wide in size─close to the diffraction limit of light. To observe the biomolecular machinery and processes within synapses, in situ single-molecule techniques are emerging as powerful tools. Guided by important biological questions, this Perspective will highlight recent advances in using these techniques to obtain in situ measurements of synaptic molecules in three aspects: the cell-biological machinery within synapses, the synaptic architecture, and the synaptic neurotransmitter receptors. These advances showcase the increasing importance of single-molecule-resolution techniques for accessing subcellular biophysical and biomolecular information related to the brain.
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Affiliation(s)
- Chao Sun
- Danish Research Institute of Translational Neuroscience - DANDRITE, Nordic-EMBL Partnership for Molecular Medicine, Department of Molecular Biology and Genetics, Aarhus University, Universitetsbyen 81, 8000 Aarhus C, Denmark
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18
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Delhaye M, LeDue J, Robinson K, Xu Q, Zhang Q, Oku S, Zhang P, Craig AM. Adaptation of Magnified Analysis of the Proteome for Excitatory Synaptic Proteins in Varied Samples and Evaluation of Cell Type-Specific Distributions. J Neurosci 2024; 44:e1291232024. [PMID: 38360747 PMCID: PMC10993037 DOI: 10.1523/jneurosci.1291-23.2024] [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: 07/11/2023] [Revised: 02/02/2024] [Accepted: 02/07/2024] [Indexed: 02/17/2024] Open
Abstract
Growing evidence suggests a remarkable diversity and complexity in the molecular composition of synapses, forming the basis for the brain to execute complex behaviors. Hence, there is considerable interest in visualizing the spatial distribution of such molecular diversity at individual synapses within intact brain circuits. Yet this task presents significant technical challenges. Expansion microscopy approaches have revolutionized our view of molecular anatomy. However, their use to study synapse-related questions outside of the labs developing them has been limited. Here we independently adapted a version of Magnified Analysis of the Proteome (MAP) and present a step-by-step protocol for visualizing over 40 synaptic proteins in brain circuits. Surprisingly, our findings show that the advantage of MAP over conventional immunolabeling was primarily due to improved antigen recognition and secondarily physical expansion. Furthermore, we demonstrated the versatile use of MAP in brains perfused with paraformaldehyde or fresh-fixed with formalin and in formalin-fixed paraffin-embedded tissue. These tests expand the potential applications of MAP to combinations with slice electrophysiology or clinical pathology specimens. Using male and female mice expressing YFP-ChR2 exclusively in interneurons, we revealed a distinct composition of AMPA and NMDA receptors and Shank family members at synapses on hippocampal interneurons versus on pyramidal neurons. Quantitative single synapse analyses yielded comprehensive cell type distributions of synaptic proteins and their relationships. These findings exemplify the value of the versatile adapted MAP procedure presented here as an accessible tool for the broad neuroscience community to unravel the complexity of the "synaptome" across brain circuits and disease states.
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Affiliation(s)
- Mathias Delhaye
- Djavad Mowafaghian Centre for Brain Health and Department of Psychiatry, University of British Columbia, Vancouver, British Columbia V6T 2B5, Canada
| | - Jeffrey LeDue
- Djavad Mowafaghian Centre for Brain Health and Department of Psychiatry, University of British Columbia, Vancouver, British Columbia V6T 2B5, Canada
| | - Kaylie Robinson
- Djavad Mowafaghian Centre for Brain Health and Department of Psychiatry, University of British Columbia, Vancouver, British Columbia V6T 2B5, Canada
| | - Qin Xu
- Department of Neurosciences, School of Medicine, Case Western Reserve University, Cleveland, Ohio 44106
| | - Qian Zhang
- Department of Neurosciences, School of Medicine, Case Western Reserve University, Cleveland, Ohio 44106
| | - Shinichiro Oku
- Djavad Mowafaghian Centre for Brain Health and Department of Psychiatry, University of British Columbia, Vancouver, British Columbia V6T 2B5, Canada
| | - Peng Zhang
- Djavad Mowafaghian Centre for Brain Health and Department of Psychiatry, University of British Columbia, Vancouver, British Columbia V6T 2B5, Canada
- Department of Neurosciences, School of Medicine, Case Western Reserve University, Cleveland, Ohio 44106
| | - Ann Marie Craig
- Djavad Mowafaghian Centre for Brain Health and Department of Psychiatry, University of British Columbia, Vancouver, British Columbia V6T 2B5, Canada
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19
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Marcó de la Cruz B, Campos J, Molinaro A, Xie X, Jin G, Wei Z, Acuna C, Sterky FH. Liprin-α proteins are master regulators of human presynapse assembly. Nat Neurosci 2024; 27:629-642. [PMID: 38472649 PMCID: PMC11001580 DOI: 10.1038/s41593-024-01592-9] [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: 07/16/2023] [Accepted: 01/30/2024] [Indexed: 03/14/2024]
Abstract
The formation of mammalian synapses entails the precise alignment of presynaptic release sites with postsynaptic receptors but how nascent cell-cell contacts translate into assembly of presynaptic specializations remains unclear. Guided by pioneering work in invertebrates, we hypothesized that in mammalian synapses, liprin-α proteins directly link trans-synaptic initial contacts to downstream steps. Here we show that, in human neurons lacking all four liprin-α isoforms, nascent synaptic contacts are formed but recruitment of active zone components and accumulation of synaptic vesicles is blocked, resulting in 'empty' boutons and loss of synaptic transmission. Interactions with presynaptic cell adhesion molecules of either the LAR-RPTP family or neurexins via CASK are required to localize liprin-α to nascent synaptic sites. Liprin-α subsequently recruits presynaptic components via a direct interaction with ELKS proteins. Thus, assembly of human presynaptic terminals is governed by a hierarchical sequence of events in which the recruitment of liprin-α proteins by presynaptic cell adhesion molecules is a critical initial step.
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Affiliation(s)
- Berta Marcó de la Cruz
- Department of Laboratory Medicine, Institute for Biomedicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
- Wallenberg Centre for Molecular and Translational Medicine, University of Gothenburg, Gothenburg, Sweden
| | - Joaquín Campos
- Chica and Heinz Schaller Foundation, Institute of Anatomy and Cell Biology, Heidelberg University, Heidelberg, Germany
| | - Angela Molinaro
- Department of Laboratory Medicine, Institute for Biomedicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
- Wallenberg Centre for Molecular and Translational Medicine, University of Gothenburg, Gothenburg, Sweden
| | - Xingqiao Xie
- School of Life Sciences, Southern University of Science and Technology, Shenzhen, China
- Brain Research Center, Southern University of Science and Technology, Shenzhen, China
- Shenzhen Key Laboratory of Biomolecular Assembling and Regulation, Shenzhen, China
| | - Gaowei Jin
- School of Life Sciences, Southern University of Science and Technology, Shenzhen, China
- Brain Research Center, Southern University of Science and Technology, Shenzhen, China
| | - Zhiyi Wei
- School of Life Sciences, Southern University of Science and Technology, Shenzhen, China
- Brain Research Center, Southern University of Science and Technology, Shenzhen, China
- Shenzhen Key Laboratory of Biomolecular Assembling and Regulation, Shenzhen, China
| | - Claudio Acuna
- Chica and Heinz Schaller Foundation, Institute of Anatomy and Cell Biology, Heidelberg University, Heidelberg, Germany.
| | - Fredrik H Sterky
- Department of Laboratory Medicine, Institute for Biomedicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden.
- Wallenberg Centre for Molecular and Translational Medicine, University of Gothenburg, Gothenburg, Sweden.
- Department of Clinical Chemistry, Sahlgrenska University Hospital, Gothenburg, Sweden.
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20
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Unterauer EM, Shetab Boushehri S, Jevdokimenko K, Masullo LA, Ganji M, Sograte-Idrissi S, Kowalewski R, Strauss S, Reinhardt SCM, Perovic A, Marr C, Opazo F, Fornasiero EF, Jungmann R. Spatial proteomics in neurons at single-protein resolution. Cell 2024; 187:1785-1800.e16. [PMID: 38552614 DOI: 10.1016/j.cell.2024.02.045] [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: 05/17/2023] [Revised: 11/28/2023] [Accepted: 02/29/2024] [Indexed: 04/02/2024]
Abstract
To understand biological processes, it is necessary to reveal the molecular heterogeneity of cells by gaining access to the location and interaction of all biomolecules. Significant advances were achieved by super-resolution microscopy, but such methods are still far from reaching the multiplexing capacity of proteomics. Here, we introduce secondary label-based unlimited multiplexed DNA-PAINT (SUM-PAINT), a high-throughput imaging method that is capable of achieving virtually unlimited multiplexing at better than 15 nm resolution. Using SUM-PAINT, we generated 30-plex single-molecule resolved datasets in neurons and adapted omics-inspired analysis for data exploration. This allowed us to reveal the complexity of synaptic heterogeneity, leading to the discovery of a distinct synapse type. We not only provide a resource for researchers, but also an integrated acquisition and analysis workflow for comprehensive spatial proteomics at single-protein resolution.
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Affiliation(s)
- Eduard M Unterauer
- Max Planck Institute of Biochemistry, Planegg, Germany; Faculty of Physics and Center for NanoScience, Ludwig-Maximilians-Universität, Munich, Germany
| | - Sayedali Shetab Boushehri
- Institute of AI for Health, Helmholtz Zentrum München - German Research Center for Environmental Health, Neuherberg, Germany; Data & Analytics, Roche Pharma Research and Early Development, Roche Innovation Center Munich, Munich, Germany; Department of Mathematics, Technical University of Munich, Munich, Germany
| | - Kristina Jevdokimenko
- Institute of Neuro- and Sensory Physiology, University Medical Center Göttingen, Göttingen, Germany
| | | | - Mahipal Ganji
- Max Planck Institute of Biochemistry, Planegg, Germany; Department of Biochemistry, Indian Institute of Science, Bangalore, India
| | - Shama Sograte-Idrissi
- Institute of Neuro- and Sensory Physiology, University Medical Center Göttingen, Göttingen, Germany; Center for Biostructural Imaging of Neurodegeneration, University Medical Center Göttingen, Göttingen, Germany
| | - Rafal Kowalewski
- Max Planck Institute of Biochemistry, Planegg, Germany; Faculty of Physics and Center for NanoScience, Ludwig-Maximilians-Universität, Munich, Germany
| | - Sebastian Strauss
- Max Planck Institute of Biochemistry, Planegg, Germany; Faculty of Physics and Center for NanoScience, Ludwig-Maximilians-Universität, Munich, Germany
| | - Susanne C M Reinhardt
- Max Planck Institute of Biochemistry, Planegg, Germany; Faculty of Physics and Center for NanoScience, Ludwig-Maximilians-Universität, Munich, Germany
| | - Ana Perovic
- Max Planck Institute of Biochemistry, Planegg, Germany
| | - Carsten Marr
- Institute of AI for Health, Helmholtz Zentrum München - German Research Center for Environmental Health, Neuherberg, Germany; Department of Mathematics, Technical University of Munich, Munich, Germany
| | - Felipe Opazo
- Institute of Neuro- and Sensory Physiology, University Medical Center Göttingen, Göttingen, Germany; Center for Biostructural Imaging of Neurodegeneration, University Medical Center Göttingen, Göttingen, Germany; NanoTag Biotechnologies GmbH, Göttingen, Germany
| | - Eugenio F Fornasiero
- Institute of Neuro- and Sensory Physiology, University Medical Center Göttingen, Göttingen, Germany; Department of Life Sciences, University of Trieste, Trieste, Italy.
| | - Ralf Jungmann
- Max Planck Institute of Biochemistry, Planegg, Germany; Faculty of Physics and Center for NanoScience, Ludwig-Maximilians-Universität, Munich, Germany.
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21
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Vandael D, Jonas P. Structure, biophysics, and circuit function of a "giant" cortical presynaptic terminal. Science 2024; 383:eadg6757. [PMID: 38452088 DOI: 10.1126/science.adg6757] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2023] [Accepted: 01/19/2024] [Indexed: 03/09/2024]
Abstract
The hippocampal mossy fiber synapse, formed between axons of dentate gyrus granule cells and dendrites of CA3 pyramidal neurons, is a key synapse in the trisynaptic circuitry of the hippocampus. Because of its comparatively large size, this synapse is accessible to direct presynaptic recording, allowing a rigorous investigation of the biophysical mechanisms of synaptic transmission and plasticity. Furthermore, because of its placement in the very center of the hippocampal memory circuit, this synapse seems to be critically involved in several higher network functions, such as learning, memory, pattern separation, and pattern completion. Recent work based on new technologies in both nanoanatomy and nanophysiology, including presynaptic patch-clamp recording, paired recording, super-resolution light microscopy, and freeze-fracture and "flash-and-freeze" electron microscopy, has provided new insights into the structure, biophysics, and network function of this intriguing synapse. This brings us one step closer to answering a fundamental question in neuroscience: how basic synaptic properties shape higher network computations.
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Affiliation(s)
- David Vandael
- Institute of Science and Technology Austria (ISTA), A-3400 Klosterneuburg, Austria
| | - Peter Jonas
- Institute of Science and Technology Austria (ISTA), A-3400 Klosterneuburg, Austria
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22
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Chen JJ, Kaufmann WA, Chen C, Arai I, Kim O, Shigemoto R, Jonas P. Developmental transformation of Ca 2+ channel-vesicle nanotopography at a central GABAergic synapse. Neuron 2024; 112:755-771.e9. [PMID: 38215739 DOI: 10.1016/j.neuron.2023.12.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2022] [Revised: 07/12/2023] [Accepted: 12/05/2023] [Indexed: 01/14/2024]
Abstract
The coupling between Ca2+ channels and release sensors is a key factor defining the signaling properties of a synapse. However, the coupling nanotopography at many synapses remains unknown, and it is unclear how it changes during development. To address these questions, we examined coupling at the cerebellar inhibitory basket cell (BC)-Purkinje cell (PC) synapse. Biophysical analysis of transmission by paired recording and intracellular pipette perfusion revealed that the effects of exogenous Ca2+ chelators decreased during development, despite constant reliance of release on P/Q-type Ca2+ channels. Structural analysis by freeze-fracture replica labeling (FRL) and transmission electron microscopy (EM) indicated that presynaptic P/Q-type Ca2+ channels formed nanoclusters throughout development, whereas docked vesicles were only clustered at later developmental stages. Modeling suggested a developmental transformation from a more random to a more clustered coupling nanotopography. Thus, presynaptic signaling developmentally approaches a point-to-point configuration, optimizing speed, reliability, and energy efficiency of synaptic transmission.
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Affiliation(s)
- Jing-Jing Chen
- Institute of Science and Technology Austria (ISTA), Am Campus 1, 3400 Klosterneuburg, Austria
| | - Walter A Kaufmann
- Institute of Science and Technology Austria (ISTA), Am Campus 1, 3400 Klosterneuburg, Austria
| | - Chong Chen
- Institute of Science and Technology Austria (ISTA), Am Campus 1, 3400 Klosterneuburg, Austria
| | - Itaru Arai
- Institute of Science and Technology Austria (ISTA), Am Campus 1, 3400 Klosterneuburg, Austria
| | - Olena Kim
- Institute of Science and Technology Austria (ISTA), Am Campus 1, 3400 Klosterneuburg, Austria
| | - Ryuichi Shigemoto
- Institute of Science and Technology Austria (ISTA), Am Campus 1, 3400 Klosterneuburg, Austria
| | - Peter Jonas
- Institute of Science and Technology Austria (ISTA), Am Campus 1, 3400 Klosterneuburg, Austria.
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23
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Hunter D, Petit-Pedrol M, Fernandes D, Bénac N, Rodrigues C, Kreye J, Ceanga M, Prüss H, Geis C, Groc L. Converging synaptic and network dysfunctions in distinct autoimmune encephalitis. EMBO Rep 2024; 25:1623-1649. [PMID: 38253690 PMCID: PMC10933378 DOI: 10.1038/s44319-024-00056-2] [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: 08/29/2023] [Revised: 12/18/2023] [Accepted: 01/02/2024] [Indexed: 01/24/2024] Open
Abstract
Psychiatric and neurological symptoms, as well as cognitive deficits, represent a prominent phenotype associated with variable forms of autoimmune encephalitis, regardless of the neurotransmitter receptor targeted by autoantibodies. The mechanistic underpinnings of these shared major neuropsychiatric symptoms remain however unclear. Here, we investigate the impacts of patient-derived monoclonal autoantibodies against the glutamatergic NMDAR (NMDAR mAb) and inhibitory GABAaR (GABAaR mAb) signalling in the hippocampal network. Unexpectedly, both excitatory and inhibitory synaptic receptor membrane dynamics, content and transmissions are altered by NMDAR or GABAaR mAb, irrespective of the affinity or antagonistic effect of the autoantibodies. The effect of NMDAR mAb on inhibitory synapses and GABAaR mAb on excitatory synapses requires neuronal activity and involves protein kinase signalling. At the cell level, both autoantibodies increase the excitation/inhibition balance of principal cell inputs. Furthermore, NMDAR or GABAaR mAb leads to hyperactivation of hippocampal networks through distinct alterations of principal cell and interneuron properties. Thus, autoantibodies targeting excitatory NMDAR or inhibitory GABAaR trigger convergent network dysfunctions through a combination of shared and distinct mechanisms.
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Affiliation(s)
- Daniel Hunter
- University of Bordeaux, CNRS, Interdisciplinary Institute for Neuroscience, IINS, UMR 5297, F-33000, Bordeaux, France
| | - Mar Petit-Pedrol
- University of Bordeaux, CNRS, Interdisciplinary Institute for Neuroscience, IINS, UMR 5297, F-33000, Bordeaux, France
| | - Dominique Fernandes
- University of Bordeaux, CNRS, Interdisciplinary Institute for Neuroscience, IINS, UMR 5297, F-33000, Bordeaux, France
| | - Nathan Bénac
- University of Bordeaux, CNRS, Interdisciplinary Institute for Neuroscience, IINS, UMR 5297, F-33000, Bordeaux, France
| | - Catarina Rodrigues
- University of Bordeaux, CNRS, Interdisciplinary Institute for Neuroscience, IINS, UMR 5297, F-33000, Bordeaux, France
| | - Jakob Kreye
- German Center for Neurodegenerative Diseases (DZNE) Berlin, 10117, Berlin, Germany
- Department of Neurology and Experimental Neurology, Charité-Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität Berlin, 10117, Berlin, Germany
| | - Mihai Ceanga
- Hans-Berger Department of Neurology, Jena University Hospital, Jena, Germany
| | - Harald Prüss
- German Center for Neurodegenerative Diseases (DZNE) Berlin, 10117, Berlin, Germany
- Department of Neurology and Experimental Neurology, Charité-Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität Berlin, 10117, Berlin, Germany
| | - Christian Geis
- Hans-Berger Department of Neurology, Jena University Hospital, Jena, Germany
| | - Laurent Groc
- University of Bordeaux, CNRS, Interdisciplinary Institute for Neuroscience, IINS, UMR 5297, F-33000, Bordeaux, France.
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24
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Zhang Y, Liu J, Mao X, Fan H, Li F, Wang S, Li J, Li M, Zuo X. Reconstruction of Vesicle Assemblies with DNA Nanorulers for Resolving Heterogeneity of Vesicles in Live Cells. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2024; 36:e2308344. [PMID: 37921116 DOI: 10.1002/adma.202308344] [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: 08/17/2023] [Revised: 10/26/2023] [Indexed: 11/04/2023]
Abstract
Nanoscale vesicles such as synaptic vesicles play a pivotal role in efficient interneuronal communications in vivo. However, the coexistence of single vesicle and vesicle clusters in living cells increases the heterogeneity of vesicle populations, which largely complicates the quantitative analysis of the vesicles. The high spatiotemporal monitoring of vesicle assemblies is currently incompletely resolved. Here, this work uses synthetic vesicles and DNA nanorulers to reconstruct in vitro the vesicle assemblies that mimic vesicle clusters in living cells. DNA nanorulers program the lateral distance of vesicle assemblies from 3 to 10 nm. This work uses the carbon fiber nanoelectrode (CFNE) to amperometric monitor artificial vesicle assemblies with sub-10 nm interspaces, and obtain a larger proportion of complex events. This work resolves the heterogeneity of individual vesicle release kinetics in PC12 cells with the temporal resolution down to ≈0.1 ms. This work further analyzes the aggregation state of intracellular vesicles and the exocytosis of living cells with electrochemical vesicle cytometry. The results indicate that the exocytosis of vesicle clusters is critically dependent on the size of clusters. This technology has the potential as a tool to shed light on the heterogeneity analysis of vesicle populations.
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Affiliation(s)
- Yueyue Zhang
- Institute of Molecular Medicine, Shanghai Key Laboratory for Nucleic Acid Chemistry and Nanomedicine, Renji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, 200127, China
| | - Jiangbo Liu
- Institute of Molecular Medicine, Shanghai Key Laboratory for Nucleic Acid Chemistry and Nanomedicine, Renji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, 200127, China
| | - Xiuhai Mao
- Institute of Molecular Medicine, Shanghai Key Laboratory for Nucleic Acid Chemistry and Nanomedicine, Renji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, 200127, China
| | - Hongxuan Fan
- Shanghai Soong Ching Ling School, Shanghai, 201700, China
| | - Fan Li
- Institute of Molecular Medicine, Shanghai Key Laboratory for Nucleic Acid Chemistry and Nanomedicine, Renji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, 200127, China
| | - Shaopeng Wang
- Institute of Molecular Medicine, Shanghai Key Laboratory for Nucleic Acid Chemistry and Nanomedicine, Renji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, 200127, China
| | - Jiang Li
- Institute of Materials Biology, Shanghai University, Shanghai, 200444, China
| | - Min Li
- Institute of Molecular Medicine, Shanghai Key Laboratory for Nucleic Acid Chemistry and Nanomedicine, Renji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, 200127, China
| | - Xiaolei Zuo
- Institute of Molecular Medicine, Shanghai Key Laboratory for Nucleic Acid Chemistry and Nanomedicine, Renji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, 200127, China
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25
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Sachs S, Reinhard S, Eilts J, Sauer M, Werner C. Visualizing the trans-synaptic arrangement of synaptic proteins by expansion microscopy. Front Cell Neurosci 2024; 18:1328726. [PMID: 38486709 PMCID: PMC10937466 DOI: 10.3389/fncel.2024.1328726] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2023] [Accepted: 02/13/2024] [Indexed: 03/17/2024] Open
Abstract
High fidelity synaptic neurotransmission in the millisecond range is provided by a defined structural arrangement of synaptic proteins. At the presynapse multi-epitope scaffolding proteins are organized spatially at release sites to guarantee optimal binding of neurotransmitters at receptor clusters. The organization of pre- and postsynaptic proteins in trans-synaptic nanocolumns would thus intuitively support efficient information transfer at the synapse. Visualization of these protein-dense regions as well as the minute size of protein-packed synaptic clefts remains, however, challenging. To enable efficient labeling of these protein complexes, we developed post-gelation immunolabeling expansion microscopy combined with Airyscan super-resolution microscopy. Using ~8-fold expanded samples, Airyscan enables multicolor fluorescence imaging with 20-40 nm spatial resolution. Post-immunolabeling of decrowded (expanded) samples provides increased labeling efficiency and allows the visualization of trans-synaptic nanocolumns. Our approach is ideally suited to investigate the pathological impact on nanocolumn arrangement e.g., in limbic encephalitis with autoantibodies targeting trans-synaptic leucine-rich glioma inactivated 1 protein (LGI1).
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Affiliation(s)
| | | | | | | | - Christian Werner
- Department of Biotechnology and Biophysics, Biocenter, University of Würzburg, Würzburg, Germany
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26
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Chen JH, Tang AH. Nanoscale Reorganization of Glutamate Receptors Underlies Synaptic Plasticity and Pathology. Neurosci Bull 2024:10.1007/s12264-024-01180-8. [PMID: 38372930 DOI: 10.1007/s12264-024-01180-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2023] [Accepted: 11/25/2023] [Indexed: 02/20/2024] Open
Affiliation(s)
- Jia-Hui Chen
- Hefei National Laboratory for Physical Sciences at the Microscale, CAS Key Laboratory of Brain Function and Disease, Neurodegenerative Disorder Research Center and Biomedical Sciences and Health Laboratory of Anhui Province, University of Science and Technology of China, Hefei, 230027, China.
- Institute of Artificial Intelligence, Hefei Comprehensive National Science Center, Hefei, 230088, China.
| | - Ai-Hui Tang
- Hefei National Laboratory for Physical Sciences at the Microscale, CAS Key Laboratory of Brain Function and Disease, Neurodegenerative Disorder Research Center and Biomedical Sciences and Health Laboratory of Anhui Province, University of Science and Technology of China, Hefei, 230027, China.
- Institute of Artificial Intelligence, Hefei Comprehensive National Science Center, Hefei, 230088, China.
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27
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Miyano R, Sakamoto H, Hirose K, Sakaba T. RIM-BP2 regulates Ca 2+ channel abundance and neurotransmitter release at hippocampal mossy fiber terminals. eLife 2024; 12:RP90799. [PMID: 38329474 PMCID: PMC10945523 DOI: 10.7554/elife.90799] [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] [Indexed: 02/09/2024] Open
Abstract
Synaptic vesicles dock and fuse at the presynaptic active zone (AZ), the specialized site for transmitter release. AZ proteins play multiple roles such as recruitment of Ca2+ channels as well as synaptic vesicle docking, priming, and fusion. However, the precise role of each AZ protein type remains unknown. In order to dissect the role of RIM-BP2 at mammalian cortical synapses having low release probability, we applied direct electrophysiological recording and super-resolution imaging to hippocampal mossy fiber terminals of RIM-BP2 knockout (KO) mice. By using direct presynaptic recording, we found the reduced Ca2+ currents. The measurements of excitatory postsynaptic currents (EPSCs) and presynaptic capacitance suggested that the initial release probability was lowered because of the reduced Ca2+ influx and impaired fusion competence in RIM-BP2 KO. Nevertheless, larger Ca2+ influx restored release partially. Consistent with presynaptic recording, STED microscopy suggested less abundance of P/Q-type Ca2+ channels at AZs deficient in RIM-BP2. Our results suggest that the RIM-BP2 regulates both Ca2+ channel abundance and transmitter release at mossy fiber synapses.
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Affiliation(s)
- Rinako Miyano
- Graduate School of Brain Science, Doshisha UniversityKyotoJapan
| | - Hirokazu Sakamoto
- Department of Pharmacology, Graduate School of Medicine, The University of TokyoBunkyo-kuJapan
| | - Kenzo Hirose
- Department of Pharmacology, Graduate School of Medicine, The University of TokyoBunkyo-kuJapan
- International Research Center for Neurointelligence (WPI-IRCN), The University of TokyoBunkyo-kuJapan
| | - Takeshi Sakaba
- Graduate School of Brain Science, Doshisha UniversityKyotoJapan
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28
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Clavet-Fournier V, Lee C, Wegner W, Brose N, Rhee J, Willig KI. Pre- and postsynaptic nanostructures increase in size and complexity after induction of long-term potentiation. iScience 2024; 27:108679. [PMID: 38213627 PMCID: PMC10783556 DOI: 10.1016/j.isci.2023.108679] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2023] [Revised: 11/09/2023] [Accepted: 12/05/2023] [Indexed: 01/13/2024] Open
Abstract
Synapses, specialized contact sites between neurons, are the fundamental elements of neuronal information transfer. Synaptic plasticity involves changes in synaptic morphology and the number of neurotransmitter receptors, and is thought to underlie learning and memory. However, it is not clear how these structural and functional changes are connected. We utilized time-lapse super-resolution STED microscopy of organotypic hippocampal brain slices and cultured neurons to visualize structural changes of the synaptic nano-organization of the postsynaptic scaffolding protein PSD95, the presynaptic scaffolding protein Bassoon, and the GluA2 subunit of AMPA receptors by chemically induced long-term potentiation (cLTP) at the level of single synapses. We found that the nano-organization of all three proteins increased in complexity and size after cLTP induction. The increase was largely synchronous, peaking at ∼60 min after stimulation. Therefore, both the size and complexity of individual pre- and post-synaptic nanostructures serve as substrates for tuning and determining synaptic strength.
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Affiliation(s)
- Valérie Clavet-Fournier
- Group of Optical Nanoscopy in Neuroscience, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany
- Göttingen Graduate Center for Neurosciences, Biophysics, und Molecular Biosciences (GGNB), Göttingen, Germany
| | - ChungKu Lee
- Department of Molecular Neurobiology, Synaptic Physiology Group, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany
| | - Waja Wegner
- Group of Optical Nanoscopy in Neuroscience, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany
- Center for Nanoscale Microscopy and Molecular Physiology of the Brain, University Medical Center Göttingen, Göttingen, Germany
| | - Nils Brose
- Department of Molecular Neurobiology, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany
| | - JeongSeop Rhee
- Department of Molecular Neurobiology, Synaptic Physiology Group, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany
| | - Katrin I. Willig
- Group of Optical Nanoscopy in Neuroscience, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany
- Center for Nanoscale Microscopy and Molecular Physiology of the Brain, University Medical Center Göttingen, Göttingen, Germany
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29
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Wong HHW, Watt AJ, Sjöström PJ. Synapse-specific burst coding sustained by local axonal translation. Neuron 2024; 112:264-276.e6. [PMID: 37944518 DOI: 10.1016/j.neuron.2023.10.011] [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: 06/05/2023] [Revised: 08/19/2023] [Accepted: 09/13/2023] [Indexed: 11/12/2023]
Abstract
Neurotransmission in the brain is unreliable, suggesting that high-frequency spike bursts rather than individual spikes carry the neural code. For instance, cortical pyramidal neurons rely on bursts in memory formation. Protein synthesis is another key factor in long-term synaptic plasticity and learning but is widely considered unnecessary for synaptic transmission. Here, however, we show that burst neurotransmission at synapses between neocortical layer 5 pyramidal cells depends on axonal protein synthesis linked to presynaptic NMDA receptors and mTOR. We localized protein synthesis to axons with laser axotomy and puromycylation live imaging. We whole-cell recorded connected neurons to reveal how translation sustained readily releasable vesicle pool size and replenishment rate. We live imaged axons and found sparsely docked RNA granules, suggesting synapse-specific regulation. In agreement, translation boosted neurotransmission onto excitatory but not inhibitory basket or Martinotti cells. Local axonal mRNA translation is thus a hitherto unappreciated principle for sustaining burst coding at specific synapse types.
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Affiliation(s)
- Hovy Ho-Wai Wong
- Centre for Research in Neuroscience, Brain Repair and Integrative Neuroscience Program, Department of Medicine, Department of Neurology and Neurosurgery, The Research Institute of the McGill University Health Centre, Montreal General Hospital, Montreal, QC H3G 1A4, Canada.
| | - Alanna J Watt
- Biology Department, McGill University, Montreal, QC H3G 0B1, Canada
| | - P Jesper Sjöström
- Centre for Research in Neuroscience, Brain Repair and Integrative Neuroscience Program, Department of Medicine, Department of Neurology and Neurosurgery, The Research Institute of the McGill University Health Centre, Montreal General Hospital, Montreal, QC H3G 1A4, Canada.
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30
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Dharmasri PA, DeMarco EM, Anderson MC, Levy AD, Blanpied TA. Loss of postsynaptic NMDARs drives nanoscale reorganization of Munc13-1 and PSD-95. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.01.12.574705. [PMID: 38260705 PMCID: PMC10802569 DOI: 10.1101/2024.01.12.574705] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/24/2024]
Abstract
Nanoscale protein organization within the active zone (AZ) and post-synaptic density (PSD) influences synaptic transmission. Nanoclusters of presynaptic Munc13-1 are associated with readily releasable pool size and neurotransmitter vesicle priming, while postsynaptic PSD-95 nanoclusters coordinate glutamate receptors across from release sites to control their opening probability. Nanocluster number, size, and protein density vary between synapse types and with development and plasticity, supporting a wide range of functional states at the synapse. Whether or how the receptors themselves control this critical architecture remains unclear. One prominent PSD molecular complex is the NMDA receptor (NMDAR). NMDARs coordinate several modes of signaling within synapses, giving them the potential to influence synaptic organization through direct protein interactions or through signaling. We found that loss of NMDARs results in larger synapses that contain smaller, denser, and more numerous PSD-95 nanoclusters. Intriguingly, NMDAR loss also generates retrograde reorganization of the active zone, resulting in denser, more numerous Munc13-1 nanoclusters, more of which are aligned with PSD-95 nanoclusters. Together, these changes to synaptic nanostructure predict stronger AMPA receptor-mediated transmission in the absence of NMDARs. Notably, while prolonged antagonism of NMDAR activity increases Munc13-1 density within nanoclusters, it does not fully recapitulate these trans-synaptic effects. Thus, our results confirm that NMDARs play an important role in maintaining pre- and postsynaptic nanostructure and suggest that both decreased NMDAR expression and suppressed NMDAR activity may exert distinct effects on synaptic function, yet through unique architectural mechanisms.
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Affiliation(s)
- Poorna A Dharmasri
- Program in Neuroscience, University of Maryland School of Medicine, Baltimore, MD, USA
- Department of Physiology, University of Maryland School of Medicine, Baltimore, MD, USA
- University of Maryland Medicine Institute of Neuroscience Discovery, Baltimore, MD, USA
- Current address: Solomon H. Snyder Department of Neuroscience, Johns Hopkins University, School of Medicine, Baltimore, MD, USA
| | - Emily M DeMarco
- Program in Neuroscience, University of Maryland School of Medicine, Baltimore, MD, USA
- Department of Physiology, University of Maryland School of Medicine, Baltimore, MD, USA
- University of Maryland Medicine Institute of Neuroscience Discovery, Baltimore, MD, USA
| | - Michael C Anderson
- Program in Neuroscience, University of Maryland School of Medicine, Baltimore, MD, USA
- Department of Physiology, University of Maryland School of Medicine, Baltimore, MD, USA
- University of Maryland Medicine Institute of Neuroscience Discovery, Baltimore, MD, USA
| | - Aaron D Levy
- Department of Physiology, University of Maryland School of Medicine, Baltimore, MD, USA
- University of Maryland Medicine Institute of Neuroscience Discovery, Baltimore, MD, USA
| | - Thomas A Blanpied
- Department of Physiology, University of Maryland School of Medicine, Baltimore, MD, USA
- University of Maryland Medicine Institute of Neuroscience Discovery, Baltimore, MD, USA
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31
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Gormal RS, Martinez-Marmol R, Brooks AJ, Meunier FA. Location, location, location: Protein kinase nanoclustering for optimised signalling output. eLife 2024; 13:e93902. [PMID: 38206309 PMCID: PMC10783869 DOI: 10.7554/elife.93902] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2023] [Accepted: 12/18/2023] [Indexed: 01/12/2024] Open
Abstract
Protein kinases (PKs) are proteins at the core of cellular signalling and are thereby responsible for most cellular physiological processes and their regulations. As for all intracellular proteins, PKs are subjected to Brownian thermal energy that tends to homogenise their distribution throughout the volume of the cell. To access their substrates and perform their critical functions, PK localisation is therefore tightly regulated in space and time, relying upon a range of clustering mechanisms. These include post-translational modifications, protein-protein and protein-lipid interactions, as well as liquid-liquid phase separation, allowing spatial restriction and ultimately regulating access to their substrates. In this review, we will focus on key mechanisms mediating PK nanoclustering in physiological and pathophysiological processes. We propose that PK nanoclusters act as a cellular quantal unit of signalling output capable of integration and regulation in space and time. We will specifically outline the various super-resolution microscopy approaches currently used to elucidate the composition and mechanisms driving PK nanoscale clustering and explore the pathological consequences of altered kinase clustering in the context of neurodegenerative disorders, inflammation, and cancer.
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Affiliation(s)
- Rachel S Gormal
- Clem Jones Centre for Ageing Dementia Research, Queensland Brain Institute, The University of QueenslandBrisbaneAustralia
| | - Ramon Martinez-Marmol
- Clem Jones Centre for Ageing Dementia Research, Queensland Brain Institute, The University of QueenslandBrisbaneAustralia
| | - Andrew J Brooks
- Frazer Institute, The University of QueenslandWoolloongabbaAustralia
| | - Frédéric A Meunier
- Clem Jones Centre for Ageing Dementia Research, Queensland Brain Institute, The University of QueenslandBrisbaneAustralia
- School of Biomedical Sciences, The University of QueenslandSt LuciaAustralia
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32
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Adrien V, Reffay M, Taulier N, Verchère A, Monlezun L, Picard M, Ducruix A, Broutin I, Pincet F, Urbach W. Kinetic study of membrane protein interactions: from three to two dimensions. Sci Rep 2024; 14:882. [PMID: 38195620 PMCID: PMC10776792 DOI: 10.1038/s41598-023-50827-5] [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: 04/02/2023] [Accepted: 12/26/2023] [Indexed: 01/11/2024] Open
Abstract
Molecular interactions are contingent upon the system's dimensionality. Notably, comprehending the impact of dimensionality on protein-protein interactions holds paramount importance in foreseeing protein behaviour across diverse scenarios, encompassing both solution and membrane environments. Here, we unravel interactions among membrane proteins across various dimensionalities by quantifying their binding rates through fluorescence recovery experiments. Our findings are presented through the examination of two protein systems: streptavidin-biotin and a protein complex constituting a bacterial efflux pump. We present here an original approach for gauging a two-dimensional binding constant between membrane proteins embedded in two opposite membranes. The quotient of protein binding rates in solution and on the membrane represents a metric denoting the exploration distance of the interacting sites-a novel interpretation.
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Affiliation(s)
- Vladimir Adrien
- Laboratoire de Physique de l'École normale superieure, École Normale Supérieure, Université Paris Sciences et Lettres, CNRS, Sorbonne Université, Université Paris Cité, F-75005, Paris, France.
- Department of Infectious Diseases, Avicenne Hospital, AP-HP, Université Sorbonne Paris Nord, Bobigny, France.
- Université Paris Cité, Inserm UMR-S 1266, Institute of Psychiatry and Neuroscience of Paris (IPNP), Paris, France.
| | - Myriam Reffay
- Laboratoire Matière et Systèmes Complexes, UMR 7057, CNRS and Université de Paris Cité, 75205, Paris Cedex 13, France
| | - Nicolas Taulier
- Sorbonne Université, CNRS, INSERM, Laboratoire d'Imagerie Biomédicale-LIB, 75006, Paris, France
| | - Alice Verchère
- Laboratoire CiTCoM, Faculté de Santé, Université Paris Cité, CNRS, 75006, Paris, France
| | - Laura Monlezun
- Université Paris Cité, CNRS, Expression Génétique Microbienne, Institut de Biologie Physico-Chimique, Paris, France
| | - Martin Picard
- Université Paris Cité, Laboratoire de Biologie Physico-Chimique des Protéines Membranaires CNRS UMR7099, 75005, Paris, France
- Institut de Biologie Physico-Chimique, Fondation Edmond de Rothschild, 75005, Paris, France
| | - Arnaud Ducruix
- Laboratoire CiTCoM, Faculté de Santé, Université Paris Cité, CNRS, 75006, Paris, France
| | - Isabelle Broutin
- Laboratoire CiTCoM, Faculté de Santé, Université Paris Cité, CNRS, 75006, Paris, France
| | - Frédéric Pincet
- Laboratoire de Physique de l'École normale superieure, École Normale Supérieure, Université Paris Sciences et Lettres, CNRS, Sorbonne Université, Université Paris Cité, F-75005, Paris, France.
| | - Wladimir Urbach
- Laboratoire de Physique de l'École normale superieure, École Normale Supérieure, Université Paris Sciences et Lettres, CNRS, Sorbonne Université, Université Paris Cité, F-75005, Paris, France.
- Sorbonne Université, CNRS, INSERM, Laboratoire d'Imagerie Biomédicale-LIB, 75006, Paris, France.
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Silva M, Tran V, Marty A. A maximum of two readily releasable vesicles per docking site at a cerebellar single active zone synapse. eLife 2024; 12:RP91087. [PMID: 38180320 PMCID: PMC10963025 DOI: 10.7554/elife.91087] [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] [Indexed: 01/06/2024] Open
Abstract
Recent research suggests that in central mammalian synapses, active zones contain several docking sites acting in parallel. Before release, one or several synaptic vesicles (SVs) are thought to bind to each docking site, forming the readily releasable pool (RRP). Determining the RRP size per docking site has important implications for short-term synaptic plasticity. Here, using mouse cerebellar slices, we take advantage of recently developed methods to count the number of released SVs at single glutamatergic synapses in response to trains of action potentials (APs). In each recording, the number of docking sites was determined by fitting with a binomial model the number of released SVs in response to individual APs. After normalization with respect to the number of docking sites, the summed number of released SVs following a train of APs was used to estimate of the RRP size per docking site. To improve this estimate, various steps were taken to maximize the release probability of docked SVs, the occupancy of docking sites, as well as the extent of synaptic depression. Under these conditions, the RRP size reached a maximum value close to two SVs per docking site. The results indicate that each docking site contains two distinct SV-binding sites that can simultaneously accommodate up to one SV each. They further suggest that under special experimental conditions, as both sites are close to full occupancy, a maximal RRP size of two SVs per docking site can be reached. More generally, the results validate a sequential two-step docking model previously proposed at this preparation.
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Affiliation(s)
- Melissa Silva
- Université Paris Cité, SPPIN-Saints Pères Paris Institute for the Neurosciences, CNRSParisFrance
| | - Van Tran
- Université Paris Cité, SPPIN-Saints Pères Paris Institute for the Neurosciences, CNRSParisFrance
| | - Alain Marty
- Université Paris Cité, SPPIN-Saints Pères Paris Institute for the Neurosciences, CNRSParisFrance
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Wu LG, Chan CY. Membrane transformations of fusion and budding. Nat Commun 2024; 15:21. [PMID: 38167896 PMCID: PMC10761761 DOI: 10.1038/s41467-023-44539-7] [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: 06/07/2023] [Accepted: 12/15/2023] [Indexed: 01/05/2024] Open
Abstract
Membrane fusion and budding mediate fundamental processes like intracellular trafficking, exocytosis, and endocytosis. Fusion is thought to open a nanometer-range pore that may subsequently close or dilate irreversibly, whereas budding transforms flat membranes into vesicles. Reviewing recent breakthroughs in real-time visualization of membrane transformations well exceeding this classical view, we synthesize a new model and describe its underlying mechanistic principles and functions. Fusion involves hemi-to-full fusion, pore expansion, constriction and/or closure while fusing vesicles may shrink, enlarge, or receive another vesicle fusion; endocytosis follows exocytosis primarily by closing Ω-shaped profiles pre-formed through the flat-to-Λ-to-Ω-shape transition or formed via fusion. Calcium/SNARE-dependent fusion machinery, cytoskeleton-dependent membrane tension, osmotic pressure, calcium/dynamin-dependent fission machinery, and actin/dynamin-dependent force machinery work together to generate fusion and budding modes differing in pore status, vesicle size, speed and quantity, controls release probability, synchronization and content release rates/amounts, and underlies exo-endocytosis coupling to maintain membrane homeostasis. These transformations, underlying mechanisms, and functions may be conserved for fusion and budding in general.
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Affiliation(s)
- Ling-Gang Wu
- National Institute of Neurological Disorders and Stroke, Bethesda, MD, USA.
| | - Chung Yu Chan
- National Institute of Neurological Disorders and Stroke, Bethesda, MD, USA
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35
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Anderson MC, Levy AD, Dharmasri PA, Metzbower SR, Blanpied TA. Trans-synaptic molecular context of NMDA receptor nanodomains. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.12.22.573055. [PMID: 38187545 PMCID: PMC10769418 DOI: 10.1101/2023.12.22.573055] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/09/2024]
Abstract
Tight coordination of the spatial relationships between protein complexes is required for cellular function. In neuronal synapses, many proteins responsible for neurotransmission organize into subsynaptic nanoclusters whose trans-cellular alignment modulates synaptic signal propagation. However, the spatial relationships between these proteins and NMDA receptors (NMDARs), which are required for learning and memory, remain undefined. Here, we mapped the relationship of key NMDAR subunits to reference proteins in the active zone and postsynaptic density using multiplexed super-resolution DNA-PAINT microscopy. GluN2A and GluN2B subunits formed nanoclusters with diverse configurations that, surprisingly, were not localized near presynaptic vesicle release sites marked by Munc13-1. However, a subset of presynaptic sites was configured to maintain NMDAR activation: these were internally denser, aligned with abundant PSD-95, and associated closely with specific NMDAR nanodomains. This work reveals a new principle regulating NMDAR signaling and suggests that synaptic functional architecture depends on assembly of multiprotein nanodomains whose interior construction is conditional on trans-cellular relationships.
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Affiliation(s)
- Michael C Anderson
- Program in Neuroscience, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Aaron D Levy
- Department of Physiology, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Poorna A Dharmasri
- Program in Neuroscience, University of Maryland School of Medicine, Baltimore, MD, USA
- Current address: Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Sarah R Metzbower
- Department of Physiology, University of Maryland School of Medicine, Baltimore, MD, USA
- Current address: Nikon Instruments Inc, Melville, NY, USA
| | - Thomas A Blanpied
- Department of Physiology, University of Maryland School of Medicine, Baltimore, MD, USA
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36
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Mrestani A, Dannhäuser S, Pauli M, Kollmannsberger P, Hübsch M, Morris L, Langenhan T, Heckmann M, Paul MM. Nanoscaled RIM clustering at presynaptic active zones revealed by endogenous tagging. Life Sci Alliance 2023; 6:e202302021. [PMID: 37696575 PMCID: PMC10494931 DOI: 10.26508/lsa.202302021] [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: 03/02/2023] [Revised: 08/27/2023] [Accepted: 08/28/2023] [Indexed: 09/13/2023] Open
Abstract
Chemical synaptic transmission involves neurotransmitter release from presynaptic active zones (AZs). The AZ protein Rab-3-interacting molecule (RIM) is important for normal Ca2+-triggered release. However, its precise localization within AZs of the glutamatergic neuromuscular junctions of Drosophila melanogaster remains elusive. We used CRISPR/Cas9-assisted genome engineering of the rim locus to incorporate small epitope tags for targeted super-resolution imaging. A V5-tag, derived from simian virus 5, and an HA-tag, derived from human influenza virus, were N-terminally fused to the RIM Zinc finger. Whereas both variants are expressed in co-localization with the core AZ scaffold Bruchpilot, electrophysiological characterization reveals that AP-evoked synaptic release is disturbed in rimV5-Znf but not in rimHA-Znf In addition, rimHA-Znf synapses show intact presynaptic homeostatic potentiation. Combining super-resolution localization microscopy and hierarchical clustering, we detect ∼10 RIMHA-Znf subclusters with ∼13 nm diameter per AZ that are compacted and increased in numbers in presynaptic homeostatic potentiation.
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Affiliation(s)
- Achmed Mrestani
- https://ror.org/00fbnyb24 Department of Neurophysiology, Institute of Physiology, University of Würzburg, Würzburg, Germany
- Department of Neurology, Leipzig University Medical Center, Leipzig, Germany
- Division of General Biochemistry, Rudolf Schönheimer Institute of Biochemistry, Medical Faculty, Leipzig University, Leipzig, Germany
| | - Sven Dannhäuser
- https://ror.org/00fbnyb24 Department of Neurophysiology, Institute of Physiology, University of Würzburg, Würzburg, Germany
| | - Martin Pauli
- https://ror.org/00fbnyb24 Department of Neurophysiology, Institute of Physiology, University of Würzburg, Würzburg, Germany
| | | | - Martha Hübsch
- https://ror.org/00fbnyb24 Department of Neurophysiology, Institute of Physiology, University of Würzburg, Würzburg, Germany
| | - Lydia Morris
- Division of General Biochemistry, Rudolf Schönheimer Institute of Biochemistry, Medical Faculty, Leipzig University, Leipzig, Germany
| | - Tobias Langenhan
- Division of General Biochemistry, Rudolf Schönheimer Institute of Biochemistry, Medical Faculty, Leipzig University, Leipzig, Germany
| | - Manfred Heckmann
- https://ror.org/00fbnyb24 Department of Neurophysiology, Institute of Physiology, University of Würzburg, Würzburg, Germany
| | - Mila M Paul
- https://ror.org/00fbnyb24 Department of Neurophysiology, Institute of Physiology, University of Würzburg, Würzburg, Germany
- https://ror.org/03pvr2g57 Department of Orthopedic Trauma, Hand, Plastic and Reconstructive Surgery, University Hospital of Würzburg, Würzburg, Germany
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37
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Olah SS, Kareemo DJ, Buchta WC, Sinnen BL, Miller CN, Actor-Engel HS, Gookin SE, Winborn CS, Kleinjan MS, Crosby KC, Aoto J, Smith KR, Kennedy MJ. Acute reorganization of postsynaptic GABA A receptors reveals the functional impact of molecular nanoarchitecture at inhibitory synapses. Cell Rep 2023; 42:113331. [PMID: 37910506 PMCID: PMC10782565 DOI: 10.1016/j.celrep.2023.113331] [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: 06/02/2023] [Revised: 09/01/2023] [Accepted: 10/06/2023] [Indexed: 11/03/2023] Open
Abstract
Neurotransmitter receptors partition into nanometer-scale subdomains within the postsynaptic membrane that are precisely aligned with presynaptic neurotransmitter release sites. While spatial coordination between pre- and postsynaptic elements is observed at both excitatory and inhibitory synapses, the functional significance of this molecular architecture has been challenging to evaluate experimentally. Here we utilized an optogenetic clustering approach to acutely alter the nanoscale organization of the postsynaptic inhibitory scaffold gephyrin while monitoring synaptic function. Gephyrin clustering rapidly enlarged postsynaptic area, laterally displacing GABAA receptors from their normally precise apposition with presynaptic active zones. Receptor displacement was accompanied by decreased synaptic GABAA receptor currents even though presynaptic release probability and the overall abundance and function of synaptic GABAA receptors remained unperturbed. Thus, acutely repositioning neurotransmitter receptors within the postsynaptic membrane profoundly influences synaptic efficacy, establishing the functional importance of precision pre-/postsynaptic molecular coordination at inhibitory synapses.
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Affiliation(s)
- Samantha S Olah
- Department of Pharmacology, University of Colorado School of Medicine, Aurora, CO 80045, USA
| | - Dean J Kareemo
- Department of Pharmacology, University of Colorado School of Medicine, Aurora, CO 80045, USA
| | - William C Buchta
- Department of Pharmacology, University of Colorado School of Medicine, Aurora, CO 80045, USA
| | - Brooke L Sinnen
- Department of Pharmacology, University of Colorado School of Medicine, Aurora, CO 80045, USA
| | - Carley N Miller
- Department of Pharmacology, University of Colorado School of Medicine, Aurora, CO 80045, USA
| | - Hannah S Actor-Engel
- Department of Pharmacology, University of Colorado School of Medicine, Aurora, CO 80045, USA
| | - Sara E Gookin
- Department of Pharmacology, University of Colorado School of Medicine, Aurora, CO 80045, USA
| | - Christina S Winborn
- Department of Pharmacology, University of Colorado School of Medicine, Aurora, CO 80045, USA
| | - Mason S Kleinjan
- Department of Pharmacology, University of Colorado School of Medicine, Aurora, CO 80045, USA
| | - Kevin C Crosby
- Department of Pharmacology, University of Colorado School of Medicine, Aurora, CO 80045, USA
| | - Jason Aoto
- Department of Pharmacology, University of Colorado School of Medicine, Aurora, CO 80045, USA
| | - Katharine R Smith
- Department of Pharmacology, University of Colorado School of Medicine, Aurora, CO 80045, USA
| | - Matthew J Kennedy
- Department of Pharmacology, University of Colorado School of Medicine, Aurora, CO 80045, USA.
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38
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Myeong J, Stunault MI, Klyachko VA, Ashrafi G. Metabolic Regulation of Single Synaptic Vesicle Exo- and Endocytosis in Hippocampal Synapses. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.11.08.566236. [PMID: 37986894 PMCID: PMC10659320 DOI: 10.1101/2023.11.08.566236] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2023]
Abstract
Glucose has long been considered a primary source of energy for synaptic function. However, it remains unclear under what conditions alternative fuels, such as lactate/pyruvate, contribute to powering synaptic transmission. By detecting individual release events in cultured hippocampal synapses, we found that mitochondrial ATP production from oxidation of lactate/pyruvate regulates basal vesicle release probability and release location within the active zone (AZ) evoked by single action potentials (APs). Mitochondrial inhibition shifted vesicle release closer to the AZ center, suggesting that the energetic barrier for vesicle release is lower in the AZ center that the periphery. Mitochondrial inhibition also altered the efficiency of single AP evoked vesicle retrieval by increasing occurrence of ultrafast endocytosis, while inhibition of glycolysis had no effect. Mitochondria are sparsely distributed along hippocampal axons and we found that nerve terminals containing mitochondria displayed enhanced vesicle release and reuptake during high-frequency trains, irrespective of whether neurons were supplied with glucose or lactate. Thus, synaptic terminals can entirely bypass glycolysis to robustly maintain the vesicle cycle using oxidative fuels in the absence of glucose. These observations further suggest that mitochondrial metabolic function not only regulates several fundamental features of synaptic transmission but may also contribute to modulation of short-term synaptic plasticity.
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Affiliation(s)
- Jongyun Myeong
- Department of Cell Biology and Physiology, Washington University School of Medicine, St. Louis, MO, 63132, United States
| | - Marion I Stunault
- Department of Cell Biology and Physiology, Washington University School of Medicine, St. Louis, MO, 63132, United States
| | - Vitaly A Klyachko
- Department of Cell Biology and Physiology, Washington University School of Medicine, St. Louis, MO, 63132, United States
| | - Ghazaleh Ashrafi
- Department of Cell Biology and Physiology, Washington University School of Medicine, St. Louis, MO, 63132, United States
- Department of Genetics, Washington University School of Medicine, St. Louis, MO, 63132, United States
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39
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Zhang Y, Wang T, Cai Y, Cui T, Kuah M, Vicini S, Wang T. Role of α2δ-3 in regulating calcium channel localization at presynaptic active zones during homeostatic plasticity. Front Mol Neurosci 2023; 16:1253669. [PMID: 38025261 PMCID: PMC10662314 DOI: 10.3389/fnmol.2023.1253669] [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: 07/05/2023] [Accepted: 10/16/2023] [Indexed: 12/01/2023] Open
Abstract
The homeostatic modulation of synaptic transmission is an evolutionarily conserved mechanism that is critical for stabilizing the nervous system. At the Drosophila neuromuscular junction (NMJ), presynaptic homeostatic potentiation (PHP) compensates for impairments in postsynaptic glutamate receptors due to pharmacological blockade or genetic deletion. During PHP, there is an increase in presynaptic neurotransmitter release, counteracting postsynaptic changes and restoring excitation to baseline levels. Previous studies have shown that α2δ-3, an auxiliary subunit of voltage-gated calcium channels (VGCCs), is essential for both the rapid induction and sustained expression of PHP at the Drosophila NMJ. However, the molecular mechanisms by which α2δ-3 regulates neurotransmitter release during PHP remain to be elucidated. In this study, we utilized electrophysiological, confocal imaging, and super-resolution imaging approaches to explore how α2δ-3 regulates synaptic transmission during PHP. Our findings suggest that α2δ-3 governs PHP by controlling the localization of the calcium channel pore-forming α1 subunit at presynaptic release sites, or active zones. Moreover, we examined the role of two structural domains within α2δ-3 in regulating neurotransmitter release and calcium channel localization. Our results highlight that these domains in α2δ-3 serve distinct functions in controlling synaptic transmission and presynaptic calcium channel abundance, at baseline in the absence of perturbations and during PHP. In summary, our research offers compelling evidence that α2δ-3 is an indispensable signaling component for controlling calcium channel trafficking and stabilization in homeostatic plasticity.
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Affiliation(s)
- Yanfeng Zhang
- Department of Pediatric Neurology, First Hospital of Jilin University, Changchun, Jilin, China
- Department of Pharmacology and Physiology, Georgetown University Medical Center, Washington, DC, United States
| | - Ting Wang
- Department of Pharmacology and Physiology, Georgetown University Medical Center, Washington, DC, United States
| | - Yimei Cai
- Department of Pharmacology and Physiology, Georgetown University Medical Center, Washington, DC, United States
| | - Tao Cui
- Department of Pharmacology and Physiology, Georgetown University Medical Center, Washington, DC, United States
| | - Michelle Kuah
- Department of Pharmacology and Physiology, Georgetown University Medical Center, Washington, DC, United States
| | - Stefano Vicini
- Department of Pharmacology and Physiology, Georgetown University Medical Center, Washington, DC, United States
- Interdisciplinary Program in Neuroscience, Georgetown University Medical Center, Washington, DC, United States
| | - Tingting Wang
- Department of Pharmacology and Physiology, Georgetown University Medical Center, Washington, DC, United States
- Interdisciplinary Program in Neuroscience, Georgetown University Medical Center, Washington, DC, United States
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40
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Venkatesan S, Binko MA, Mielnik CA, Ramsey AJ, Lambe EK. Deficits in integrative NMDA receptors caused by Grin1 disruption can be rescued in adulthood. Neuropsychopharmacology 2023; 48:1742-1751. [PMID: 37349472 PMCID: PMC10579298 DOI: 10.1038/s41386-023-01619-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/22/2022] [Revised: 05/10/2023] [Accepted: 05/22/2023] [Indexed: 06/24/2023]
Abstract
Glutamatergic NMDA receptors (NMDAR) are critical for cognitive function, and their reduced expression leads to intellectual disability. Since subpopulations of NMDARs exist in distinct subcellular environments, their functioning may be unevenly vulnerable to genetic disruption. Here, we investigate synaptic and extrasynaptic NMDARs on the major output neurons of the prefrontal cortex in mice deficient for the obligate NMDAR subunit encoded by Grin1 and wild-type littermates. With whole-cell recording in brain slices, we find that single, low-intensity stimuli elicit surprisingly-similar glutamatergic synaptic currents in both genotypes. By contrast, clear genotype differences emerge with manipulations that recruit extrasynaptic NMDARs, including stronger, repetitive, or pharmacological stimulation. These results reveal a disproportionate functional deficit of extrasynaptic NMDARs compared to their synaptic counterparts. To probe the repercussions of this deficit, we examine an NMDAR-dependent phenomenon considered a building block of cognitive integration, basal dendrite plateau potentials. Since we find this phenomenon is readily evoked in wild-type but not in Grin1-deficient mice, we ask whether plateau potentials can be restored by an adult intervention to increase Grin1 expression. This genetic manipulation, previously shown to restore cognitive performance in adulthood, successfully rescues electrically-evoked basal dendrite plateau potentials after a lifetime of NMDAR compromise. Taken together, our work demonstrates NMDAR subpopulations are not uniformly vulnerable to the genetic disruption of their obligate subunit. Furthermore, the window for functional rescue of the more-sensitive integrative NMDARs remains open into adulthood.
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Affiliation(s)
| | - Mary A Binko
- Department of Physiology, University of Toronto, Toronto, ON, Canada
- University of Pittsburgh Medical Center, Pittsburgh, PA, USA
| | - Catharine A Mielnik
- Department of Pharmacology and Toxicology, University of Toronto, Toronto, ON, Canada
| | - Amy J Ramsey
- Department of Physiology, University of Toronto, Toronto, ON, Canada
- Department of Pharmacology and Toxicology, University of Toronto, Toronto, ON, Canada
| | - Evelyn K Lambe
- Department of Physiology, University of Toronto, Toronto, ON, Canada.
- Department of OBGYN, University of Toronto, Toronto, ON, Canada.
- Department of Psychiatry, University of Toronto, Toronto, ON, Canada.
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41
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Aberra AS, Wang R, Grill WM, Peterchev AV. Multi-scale model of axonal and dendritic polarization by transcranial direct current stimulation in realistic head geometry. Brain Stimul 2023; 16:1776-1791. [PMID: 38056825 PMCID: PMC10842743 DOI: 10.1016/j.brs.2023.11.018] [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: 07/30/2023] [Revised: 11/06/2023] [Accepted: 11/29/2023] [Indexed: 12/08/2023] Open
Abstract
BACKGROUND Transcranial direct current stimulation (tDCS) is a non-invasive brain stimulation modality that can alter cortical excitability. However, it remains unclear how the subcellular elements of different neuron types are polarized by specific electric field (E-field) distributions. OBJECTIVE To quantify neuronal polarization generated by tDCS in a multi-scale computational model. METHODS We embedded layer-specific, morphologically-realistic cortical neuron models in a finite element model of the E-field in a human head and simulated steady-state polarization generated by conventional primary-motor-cortex-supraorbital (M1-SO) and 4 × 1 high-definition (HD) tDCS. We quantified somatic, axonal, and dendritic polarization of excitatory pyramidal cells in layers 2/3, 5, and 6, as well as inhibitory interneurons in layers 1 and 4 of the hand knob. RESULTS Axonal and dendritic terminals were polarized more than the soma in all neurons, with peak axonal and dendritic polarization of 0.92 mV and 0.21 mV, respectively, compared to peak somatic polarization of 0.07 mV for 1.8 mA M1-SO stimulation. Both montages generated regions of depolarization and hyperpolarization beneath the M1 anode; M1-SO produced slightly stronger, more diffuse polarization peaking in the central sulcus, while 4 × 1 HD produced higher peak polarization in the gyral crown. The E-field component normal to the cortical surface correlated strongly with pyramidal neuron somatic polarization (R2>0.9), but exhibited weaker correlations with peak pyramidal axonal and dendritic polarization (R2:0.5-0.9) and peak polarization in all subcellular regions of interneurons (R2:0.3-0.6). Simulating polarization by uniform local E-field extracted at the soma approximated the spatial distribution of tDCS polarization but produced large errors in some regions (median absolute percent error: 7.9 %). CONCLUSIONS Polarization of pre- and postsynaptic compartments of excitatory and inhibitory cortical neurons may play a significant role in tDCS neuromodulation. These effects cannot be predicted from the E-field distribution alone but rather require calculation of the neuronal response.
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Affiliation(s)
- Aman S Aberra
- Dept. of Biomedical Engineering, Pratt School of Engineering, Duke University, NC, USA.
| | - Ruochen Wang
- Dept. of Biomedical Engineering, Pratt School of Engineering, Duke University, NC, USA; Dept. of Psychiatry and Behavioral Sciences, School of Medicine, Duke University, NC, USA.
| | - Warren M Grill
- Dept. of Biomedical Engineering, Pratt School of Engineering, Duke University, NC, USA; Dept. of Electrical and Computer Engineering, Pratt School of Engineering, Duke University, NC, USA; Dept. of Neurobiology, School of Medicine, Duke University, NC, USA; Dept. of Neurosurgery, School of Medicine, Duke University, NC, USA.
| | - Angel V Peterchev
- Dept. of Biomedical Engineering, Pratt School of Engineering, Duke University, NC, USA; Dept. of Psychiatry and Behavioral Sciences, School of Medicine, Duke University, NC, USA; Dept. of Electrical and Computer Engineering, Pratt School of Engineering, Duke University, NC, USA; Dept. of Neurosurgery, School of Medicine, Duke University, NC, USA.
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42
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Zhao J, Gao L, Nurrish S, Kaplan JM. Post-synaptic GABA A receptors potentiate transmission by recruiting CaV2 channels to their inputs. Cell Rep 2023; 42:113161. [PMID: 37742192 PMCID: PMC10873018 DOI: 10.1016/j.celrep.2023.113161] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2023] [Revised: 07/05/2023] [Accepted: 09/07/2023] [Indexed: 09/26/2023] Open
Abstract
We describe a retrograde synaptic signal at the C. elegans GABAergic neuromuscular junction. At this synapse, GABA release is controlled by two voltage-activated calcium channels (UNC-2/CaV2 and EGL-19/CaV1), and muscle responses are mediated by a single GABA receptor (UNC-49/GABAA). Mutations inactivating UNC-49 or those preventing UNC-49 synaptic clustering cause retrograde defects in GABAergic motor neurons, whereby UNC-2/CaV2 levels at active zones, UNC-2 current, and pre-synaptic GABA release are decreased. Inactivating post-synaptic GABAA receptors has no effect on GABA neuron EGL-19/CaV1 levels nor on several other pre-synaptic markers. The effect of GABAA receptors on pre-synaptic strength is not a consequence of decreased GABA transmission and is input selective. Finally, pre-synaptic UNC-2/CaV2 levels are increased when post-synaptic GABAA receptors are increased but are unaffected by increased extra-synaptic receptors. Collectively, these results suggest that clustered post-synaptic GABAA receptors adjust the strength of their inputs by recruiting CaV2 to contacting active zones.
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Affiliation(s)
- Jian Zhao
- Department of Molecular Biology, Massachusetts General Hospital, Boston, MA 02114, USA; Department of Neurobiology, Harvard Medical School, Boston, MA 02115, USA
| | - Luna Gao
- Department of Molecular Biology, Massachusetts General Hospital, Boston, MA 02114, USA; Department of Neurobiology, Harvard Medical School, Boston, MA 02115, USA
| | - Stephen Nurrish
- Department of Molecular Biology, Massachusetts General Hospital, Boston, MA 02114, USA; Department of Neurobiology, Harvard Medical School, Boston, MA 02115, USA
| | - Joshua M Kaplan
- Department of Molecular Biology, Massachusetts General Hospital, Boston, MA 02114, USA; Department of Neurobiology, Harvard Medical School, Boston, MA 02115, USA; Program in Neuroscience, Harvard Medical School, Boston, MA 02115, USA.
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43
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Emperador-Melero J, Andersen JW, Metzbower SR, Levy AD, Dharmasri PA, de Nola G, Blanpied TA, Kaeser PS. Molecular definition of distinct active zone protein machineries for Ca 2+ channel clustering and synaptic vesicle priming. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.10.27.564439. [PMID: 37961089 PMCID: PMC10634917 DOI: 10.1101/2023.10.27.564439] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2023]
Abstract
Action potentials trigger neurotransmitter release with minimal delay. Active zones mediate this temporal precision by co-organizing primed vesicles with CaV2 Ca2+ channels. The presumed model is that scaffolding proteins directly tether primed vesicles to CaV2s. We find that CaV2 clustering and vesicle priming are executed by separate machineries. At hippocampal synapses, CaV2 nanoclusters are positioned at variable distances from those of the priming protein Munc13. The active zone organizer RIM anchors both proteins, but distinct interaction motifs independently execute these functions. In heterologous cells, Liprin-α and RIM from co-assemblies that are separate from CaV2-organizing complexes upon co-transfection. At synapses, Liprin-α1-4 knockout impairs vesicle priming, but not CaV2 clustering. The cell adhesion protein PTPσ recruits Liprin-α, RIM and Munc13 into priming complexes without co-clustering of CaV2s. We conclude that active zones consist of distinct complexes to organize CaV2s and vesicle priming, and Liprin-α and PTPσ specifically support priming site assembly.
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Affiliation(s)
| | | | - Sarah R. Metzbower
- Department of Physiology, University of Maryland School of Medicine, Baltimore, USA
| | - Aaron D. Levy
- Department of Physiology, University of Maryland School of Medicine, Baltimore, USA
| | - Poorna A. Dharmasri
- Department of Physiology, University of Maryland School of Medicine, Baltimore, USA
| | | | - Thomas A. Blanpied
- Department of Physiology, University of Maryland School of Medicine, Baltimore, USA
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Bingham D, Jakobs CE, Wernert F, Boroni-Rueda F, Jullien N, Schentarra EM, Friedl K, Da Costa Moura J, van Bommel DM, Caillol G, Ogawa Y, Papandréou MJ, Leterrier C. Presynapses contain distinct actin nanostructures. J Cell Biol 2023; 222:e202208110. [PMID: 37578754 PMCID: PMC10424573 DOI: 10.1083/jcb.202208110] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2022] [Revised: 06/07/2023] [Accepted: 07/25/2023] [Indexed: 08/15/2023] Open
Abstract
The architecture of the actin cytoskeleton that concentrates at presynapses remains poorly known, hindering our understanding of its roles in synaptic physiology. In this work, we measure and visualize presynaptic actin by diffraction-limited and super-resolution microscopy, thanks to a validated model of bead-induced presynapses in cultured neurons. We identify a major population of actin-enriched presynapses that concentrates more presynaptic components and shows higher synaptic vesicle cycling than their non-enriched counterparts. Pharmacological perturbations point to an optimal actin amount and the presence of distinct actin structures within presynapses. We directly visualize these nanostructures using Single Molecule Localization Microscopy (SMLM), defining three distinct types: an actin mesh at the active zone, actin rails between the active zone and deeper reserve pools, and actin corrals around the whole presynaptic compartment. Finally, CRISPR-tagging of endogenous actin allows us to validate our results in natural synapses between cultured neurons, confirming the role of actin enrichment and the presence of three types of presynaptic actin nanostructures.
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Affiliation(s)
- Dominic Bingham
- CNRS, INP UMR7051, NeuroCyto, Aix Marseille Université, Marseille, France
| | | | - Florian Wernert
- CNRS, INP UMR7051, NeuroCyto, Aix Marseille Université, Marseille, France
| | - Fanny Boroni-Rueda
- CNRS, INP UMR7051, NeuroCyto, Aix Marseille Université, Marseille, France
| | - Nicolas Jullien
- CNRS, INP UMR7051, NeuroCyto, Aix Marseille Université, Marseille, France
| | | | - Karoline Friedl
- CNRS, INP UMR7051, NeuroCyto, Aix Marseille Université, Marseille, France
- Abbelight, Cachan, France
| | | | | | - Ghislaine Caillol
- CNRS, INP UMR7051, NeuroCyto, Aix Marseille Université, Marseille, France
| | - Yuki Ogawa
- Department of Neuroscience, Baylor College of Medicine, Houston, TX, USA
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45
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Nicoll RA, Schulman H. Synaptic memory and CaMKII. Physiol Rev 2023; 103:2877-2925. [PMID: 37290118 PMCID: PMC10642921 DOI: 10.1152/physrev.00034.2022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2022] [Revised: 04/26/2023] [Accepted: 04/30/2023] [Indexed: 06/10/2023] Open
Abstract
Ca2+/calmodulin-dependent protein kinase II (CaMKII) and long-term potentiation (LTP) were discovered within a decade of each other and have been inextricably intertwined ever since. However, like many marriages, it has had its up and downs. Based on the unique biochemical properties of CaMKII, it was proposed as a memory molecule before any physiological linkage was made to LTP. However, as reviewed here, the convincing linkage of CaMKII to synaptic physiology and behavior took many decades. New technologies were critical in this journey, including in vitro brain slices, mouse genetics, single-cell molecular genetics, pharmacological reagents, protein structure, and two-photon microscopy, as were new investigators attracted by the exciting challenge. This review tracks this journey and assesses the state of this marriage 40 years on. The collective literature impels us to propose a relatively simple model for synaptic memory involving the following steps that drive the process: 1) Ca2+ entry through N-methyl-d-aspartate (NMDA) receptors activates CaMKII. 2) CaMKII undergoes autophosphorylation resulting in constitutive, Ca2+-independent activity and exposure of a binding site for the NMDA receptor subunit GluN2B. 3) Active CaMKII translocates to the postsynaptic density (PSD) and binds to the cytoplasmic C-tail of GluN2B. 4) The CaMKII-GluN2B complex initiates a structural rearrangement of the PSD that may involve liquid-liquid phase separation. 5) This rearrangement involves the PSD-95 scaffolding protein, α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptors (AMPARs), and their transmembrane AMPAR-regulatory protein (TARP) auxiliary subunits, resulting in an accumulation of AMPARs in the PSD that underlies synaptic potentiation. 6) The stability of the modified PSD is maintained by the stability of the CaMKII-GluN2B complex. 7) By a process of subunit exchange or interholoenzyme phosphorylation CaMKII maintains synaptic potentiation in the face of CaMKII protein turnover. There are many other important proteins that participate in enlargement of the synaptic spine or modulation of the steps that drive and maintain the potentiation. In this review we critically discuss the data underlying each of the steps. As will become clear, some of these steps are more firmly grounded than others, and we provide suggestions as to how the evidence supporting these steps can be strengthened or, based on the new data, be replaced. Although the journey has been a long one, the prospect of having a detailed cellular and molecular understanding of learning and memory is at hand.
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Affiliation(s)
- Roger A Nicoll
- Department of Cellular and Molecular Pharmacology, University of California at San Francisco, San Francisco, California, United States
| | - Howard Schulman
- Department of Neurobiology, Stanford University School of Medicine, Stanford, California, United States
- Panorama Research Institute, Sunnyvale, California, United States
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Eilts J, Reinhard S, Michetschläger N, Werner C, Sauer M. Enhanced synaptic protein visualization by multicolor super-resolution expansion microscopy. NEUROPHOTONICS 2023; 10:044412. [PMID: 37886043 PMCID: PMC10599331 DOI: 10.1117/1.nph.10.4.044412] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/29/2023] [Revised: 09/07/2023] [Accepted: 09/08/2023] [Indexed: 10/28/2023]
Abstract
Significance Understanding the organization of biomolecules into complexes and their dynamics is crucial for comprehending cellular functions and dysfunctions, particularly in neuronal networks connected by synapses. In the last two decades, various powerful super-resolution (SR) microscopy techniques have been developed that produced stunning images of synapses and their molecular organization. However, current SR microscopy methods do not permit multicolor fluorescence imaging with 20 to 30 nm spatial resolution. Aim We developed a method that enables 4-color fluorescence imaging of synaptic proteins in neurons with 20 to 30 nm lateral resolution. Approach We used post-expansion immunolabeling of eightfold expanded hippocampal neurons in combination with Airyscan and structured illumination microscopy (SIM). Results We demonstrate that post-expansion immunolabeling of approximately eightfold expanded hippocampal neurons enables efficient labeling of synaptic proteins in crowded compartments with minimal linkage error and enables in combination with Airyscan and SIM four-color three-dimensional fluorescence imaging with 20 to 30 nm lateral resolution. Using immunolabeling of Synaptobrevin 2 as an efficient marker of the vesicle pool allowed us to identify individual synaptic vesicles colocalized with Rab3-interacting molecule 1 and 2 (RIM1/2), a marker of pre-synaptic fusion sites. Conclusions Our optimized expansion microscopy approach improves the visualization and location of pre- and post-synaptic proteins and can thus provide invaluable insights into the spatial organization of proteins at synapses.
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Affiliation(s)
- Janna Eilts
- University of Würzburg, Department of Biotechnology and Biophysics, Biocenter, Würzburg, Germany
| | - Sebastian Reinhard
- University of Würzburg, Department of Biotechnology and Biophysics, Biocenter, Würzburg, Germany
| | - Nikolas Michetschläger
- University of Würzburg, Department of Biotechnology and Biophysics, Biocenter, Würzburg, Germany
| | - Christian Werner
- University of Würzburg, Department of Biotechnology and Biophysics, Biocenter, Würzburg, Germany
| | - Markus Sauer
- University of Würzburg, Department of Biotechnology and Biophysics, Biocenter, Würzburg, Germany
- University of Würzburg, Rudolf Virchow Center, Research Center for Integrative and Translational Bioimaging, Würzburg, Germany
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47
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Tao-Cheng JH, Moreira SL, Winters CA, Reese TS, Dosemeci A. Modification of the synaptic cleft under excitatory conditions. Front Synaptic Neurosci 2023; 15:1239098. [PMID: 37840571 PMCID: PMC10568020 DOI: 10.3389/fnsyn.2023.1239098] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2023] [Accepted: 09/14/2023] [Indexed: 10/17/2023] Open
Abstract
The synaptic cleft is the extracellular part of the synapse, bridging the pre- and postsynaptic membranes. The geometry and molecular organization of the cleft is gaining increased attention as an important determinant of synaptic efficacy. The present study by electron microscopy focuses on short-term morphological changes at the synaptic cleft under excitatory conditions. Depolarization of cultured hippocampal neurons with high K+ results in an increased frequency of synaptic profiles with clefts widened at the periphery (open clefts), typically exhibiting patches of membranes lined by postsynaptic density, but lacking associated presynaptic membranes (18.0% open clefts in high K+ compared to 1.8% in controls). Similarly, higher frequencies of open clefts were observed in adult brain upon a delay of perfusion fixation to promote excitatory/ischemic conditions. Inhibition of basal activity in cultured neurons through the application of TTX results in the disappearance of open clefts whereas application of NMDA increases their frequency (19.0% in NMDA vs. 5.3% in control and 2.6% in APV). Depletion of extracellular Ca2+ with EGTA also promotes an increase in the frequency of open clefts (16.6% in EGTA vs. 4.0% in controls), comparable to that by depolarization or NMDA, implicating dissociation of Ca2+-dependent trans-synaptic bridges. Dissociation of transsynaptic bridges under excitatory conditions may allow perisynaptic mobile elements, such as AMPA receptors to enter the cleft. In addition, peripheral opening of the cleft would facilitate neurotransmitter clearance and thus may have a homeostatic and/or protective function.
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Affiliation(s)
- Jung-Hwa Tao-Cheng
- NINDS Electron Microscopy Facility, National Institute of Neurological Diseases and Stroke, National Institutes of Health, Bethesda, MD, United States
| | - Sandra L. Moreira
- NINDS Electron Microscopy Facility, National Institute of Neurological Diseases and Stroke, National Institutes of Health, Bethesda, MD, United States
| | - Christine A. Winters
- Laboratory of Neurobiology, National Institute of Neurological Diseases and Stroke, National Institutes of Health, Bethesda, MD, United States
| | - Thomas S. Reese
- Laboratory of Neurobiology, National Institute of Neurological Diseases and Stroke, National Institutes of Health, Bethesda, MD, United States
| | - Ayse Dosemeci
- Laboratory of Neurobiology, National Institute of Neurological Diseases and Stroke, National Institutes of Health, Bethesda, MD, United States
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Metzbower SR, Dharmasri PA, Levy AD, Anderson MC, Blanpied TA. Distinct SAP102 and PSD-95 nano-organization defines multiple types of synaptic scaffold protein domains at single synapses. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.09.12.557372. [PMID: 37745494 PMCID: PMC10515860 DOI: 10.1101/2023.09.12.557372] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/26/2023]
Abstract
The MAGUK family of scaffold proteins plays a central role in maintaining and modulating synaptic signaling, providing a framework to retain and position receptors, signaling molecules, and other synaptic components. Of these scaffold proteins, SAP102 and PSD-95 are essential for synaptic function at distinct developmental timepoints and perform overlapping as well as unique roles. While their similar structures allow for common binding partners, SAP102 is expressed earlier in synapse development and is required for synaptogenesis, whereas PSD-95 expression peaks later in development and is associated with synapse maturation. PSD-95 and other key synaptic proteins organize into subsynaptic nanodomains that have a significant impact on synaptic transmission, but the nanoscale organization of SAP102 is unknown. How SAP102 is organized within the synapse, and how it relates spatially to PSD-95 on a nanometer scale, could impact how SAP102 clusters synaptic proteins and underlie its ability to perform its unique functions. Here we used DNA-PAINT super-resolution microscopy to measure SAP102 nano-organization and its spatial relationship to PSD-95 at individual synapses. We found that like PSD-95, SAP102 accumulates in high-density subsynaptic nanoclusters. However, SAP102 nanoclusters were smaller and denser than PSD-95 nanoclusters across development. Additionally, only a subset of SAP102 nanoclusters co-organized with PSD-95, revealing that within individual synapses there are nanodomains that contain either one or both proteins. This organization into both shared and distinct subsynaptic nanodomains may underlie the ability of SAP102 and PSD-95 to perform both common and unique synaptic functions.
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Affiliation(s)
- Sarah R. Metzbower
- Department of Physiology, University of Maryland School of Medicine, Baltimore, MD 21201
| | - Poorna A. Dharmasri
- Department of Physiology, University of Maryland School of Medicine, Baltimore, MD 21201
- Program in Neuroscience, University of Maryland School of Medicine, Baltimore, MD 21201
| | - Aaron D. Levy
- Department of Physiology, University of Maryland School of Medicine, Baltimore, MD 21201
| | - Michael C. Anderson
- Department of Physiology, University of Maryland School of Medicine, Baltimore, MD 21201
- Program in Neuroscience, University of Maryland School of Medicine, Baltimore, MD 21201
| | - Thomas A. Blanpied
- Department of Physiology, University of Maryland School of Medicine, Baltimore, MD 21201
- Program in Neuroscience, University of Maryland School of Medicine, Baltimore, MD 21201
- University of Maryland Medicine Institute for Neuroscience Discovery, University of Maryland School of Medicine, Baltimore, MD 21201
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49
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Dharmasri PA, Levy AD, Blanpied TA. Differential nanoscale organization of excitatory synapses onto excitatory vs inhibitory neurons. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.09.06.556279. [PMID: 37732271 PMCID: PMC10508768 DOI: 10.1101/2023.09.06.556279] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/22/2023]
Abstract
A key feature of excitatory synapses is the existence of subsynaptic protein nanoclusters whose precise alignment across the cleft in a trans-synaptic nanocolumn influences the strength of synaptic transmission. However, whether nanocolumn properties vary between excitatory synapses functioning in different cellular contexts is unknown. We used a combination of confocal and DNA-PAINT super-resolution microscopy to directly compare the organization of shared scaffold proteins at two important excitatory synapses - those forming onto excitatory principal neurons (Ex→Ex synapses) and those forming onto parvalbumin-expressing interneurons (Ex→PV synapses). As in Ex→Ex synapses, we find that in Ex→PV synapses presynaptic Munc13-1 and postsynaptic PSD-95 both form nanoclusters that demonstrate alignment, underscoring synaptic nanostructure and the trans-synaptic nanocolumn as conserved organizational principles of excitatory synapses. Despite the general conservation of these features, we observed specific differences in the characteristics of pre- and postsynaptic Ex→PV nanostructure. Ex→PV synapses contained larger PSDs with fewer PSD-95 NCs when accounting for size than Ex→Ex synapses. Furthermore, the PSD-95 NCs were larger and denser. The identity of the postsynaptic cell also had a retrograde impact on Munc13-1 organization, as Ex→PV synapses hosted larger Munc13-1 puncta that contained less dense but larger and more numerous Munc13-1 NCs. Moreover, we measured the spatial variability of transsynaptic alignment in these synapse types, revealing protein alignment in Ex→PV synapses over a distinct range of distances compared to Ex→Ex synapses. We conclude that while general principles of nanostructure and alignment are shared, cell-specific elements of nanodomain organization likely contribute to functional diversity of excitatory synapses. Understanding the rules of synapse nanodomain assembly, which themselves are cell-type specific, will be essential for illuminating brain network dynamics.
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Affiliation(s)
- Poorna A Dharmasri
- Department of Physiology, University of Maryland School of Medicine, Baltimore, Maryland 21201
- Program in Neuroscience, University of Maryland School of Medicine, Baltimore, Maryland 21201
- University of Maryland Medicine Institute of Neuroscience Discovery, University of Maryland School of Medicine, Baltimore, Maryland 21201
| | - Aaron D Levy
- Department of Physiology, University of Maryland School of Medicine, Baltimore, Maryland 21201
- University of Maryland Medicine Institute of Neuroscience Discovery, University of Maryland School of Medicine, Baltimore, Maryland 21201
| | - Thomas A Blanpied
- Department of Physiology, University of Maryland School of Medicine, Baltimore, Maryland 21201
- Program in Neuroscience, University of Maryland School of Medicine, Baltimore, Maryland 21201
- University of Maryland Medicine Institute of Neuroscience Discovery, University of Maryland School of Medicine, Baltimore, Maryland 21201
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50
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Michalska JM, Lyudchik J, Velicky P, Štefaničková H, Watson JF, Cenameri A, Sommer C, Amberg N, Venturino A, Roessler K, Czech T, Höftberger R, Siegert S, Novarino G, Jonas P, Danzl JG. Imaging brain tissue architecture across millimeter to nanometer scales. Nat Biotechnol 2023:10.1038/s41587-023-01911-8. [PMID: 37653226 DOI: 10.1038/s41587-023-01911-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2022] [Accepted: 07/20/2023] [Indexed: 09/02/2023]
Abstract
Mapping the complex and dense arrangement of cells and their connectivity in brain tissue demands nanoscale spatial resolution imaging. Super-resolution optical microscopy excels at visualizing specific molecules and individual cells but fails to provide tissue context. Here we developed Comprehensive Analysis of Tissues across Scales (CATS), a technology to densely map brain tissue architecture from millimeter regional to nanometer synaptic scales in diverse chemically fixed brain preparations, including rodent and human. CATS uses fixation-compatible extracellular labeling and optical imaging, including stimulated emission depletion or expansion microscopy, to comprehensively delineate cellular structures. It enables three-dimensional reconstruction of single synapses and mapping of synaptic connectivity by identification and analysis of putative synaptic cleft regions. Applying CATS to the mouse hippocampal mossy fiber circuitry, we reconstructed and quantified the synaptic input and output structure of identified neurons. We furthermore demonstrate applicability to clinically derived human tissue samples, including formalin-fixed paraffin-embedded routine diagnostic specimens, for visualizing the cellular architecture of brain tissue in health and disease.
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Affiliation(s)
- Julia M Michalska
- Institute of Science and Technology Austria, Klosterneuburg, Austria
| | - Julia Lyudchik
- Institute of Science and Technology Austria, Klosterneuburg, Austria
| | - Philipp Velicky
- Institute of Science and Technology Austria, Klosterneuburg, Austria
- Core Facility Imaging, Medical University of Vienna, Vienna, Austria
| | - Hana Štefaničková
- Institute of Science and Technology Austria, Klosterneuburg, Austria
| | - Jake F Watson
- Institute of Science and Technology Austria, Klosterneuburg, Austria
| | - Alban Cenameri
- Institute of Science and Technology Austria, Klosterneuburg, Austria
| | - Christoph Sommer
- Institute of Science and Technology Austria, Klosterneuburg, Austria
| | - Nicole Amberg
- Department of Neurology, Division of Neuropathology and Neurochemistry, Medical University of Vienna, Vienna, Austria
- Comprehensive Center for Clinical Neurosciences and Mental Health, Medical University of Vienna, Vienna, Austria
| | | | - Karl Roessler
- Comprehensive Center for Clinical Neurosciences and Mental Health, Medical University of Vienna, Vienna, Austria
- Department of Neurosurgery, Medical University of Vienna, Vienna, Austria
| | - Thomas Czech
- Comprehensive Center for Clinical Neurosciences and Mental Health, Medical University of Vienna, Vienna, Austria
- Department of Neurosurgery, Medical University of Vienna, Vienna, Austria
| | - Romana Höftberger
- Department of Neurology, Division of Neuropathology and Neurochemistry, Medical University of Vienna, Vienna, Austria
- Comprehensive Center for Clinical Neurosciences and Mental Health, Medical University of Vienna, Vienna, Austria
| | - Sandra Siegert
- Institute of Science and Technology Austria, Klosterneuburg, Austria
| | - Gaia Novarino
- Institute of Science and Technology Austria, Klosterneuburg, Austria
| | - Peter Jonas
- Institute of Science and Technology Austria, Klosterneuburg, Austria
| | - Johann G Danzl
- Institute of Science and Technology Austria, Klosterneuburg, Austria.
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