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Madar AD, Jiang A, Dong C, Sheffield MEJ. Synaptic plasticity rules driving representational shifting in the hippocampus. Nat Neurosci 2025; 28:848-860. [PMID: 40113934 DOI: 10.1038/s41593-025-01894-6] [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: 10/16/2023] [Accepted: 01/17/2025] [Indexed: 03/22/2025]
Abstract
Synaptic plasticity is widely thought to support memory storage in the brain, but the rules determining impactful synaptic changes in vivo are not known. We considered the trial-by-trial shifting dynamics of hippocampal place fields (PF) as an indicator of ongoing plasticity during memory formation and familiarization. By implementing different plasticity rules in computational models of spiking place cells and comparing them to experimentally measured PFs from mice navigating familiar and new environments, we found that behavioral timescale synaptic plasticity (BTSP), rather than Hebbian spike-timing-dependent plasticity (STDP), best explains PF shifting dynamics. BTSP-triggering events are rare, but more frequent during new experiences. During exploration, their probability is dynamic-it decays after PF onset, but continually drives a population-level representational drift. Additionally, our results show that BTSP occurs in CA3 but is less frequent and phenomenologically different than in CA1. Overall, our study provides a new framework to understand how synaptic plasticity continuously shapes neuronal representations during learning.
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Affiliation(s)
- Antoine D Madar
- Department of Neurobiology, Neuroscience Institute, University of Chicago, Chicago, IL, USA.
| | - Anqi Jiang
- Department of Neurobiology, Neuroscience Institute, University of Chicago, Chicago, IL, USA
| | - Can Dong
- Department of Neurobiology, Neuroscience Institute, University of Chicago, Chicago, IL, USA
- Department of Neurobiology, Stanford University School of Medicine, Stanford, CA, USA
| | - Mark E J Sheffield
- Department of Neurobiology, Neuroscience Institute, University of Chicago, Chicago, IL, USA.
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2
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Aggarwal A, Negrean A, Chen Y, Iyer R, Reep D, Liu A, Palutla A, Xie ME, MacLennan BJ, Hagihara KM, Kinsey LW, Sun JL, Yao P, Zheng J, Tsang A, Tsegaye G, Zhang Y, Patel RH, Arthur BJ, Hiblot J, Leippe P, Tarnawski M, Marvin JS, Vevea JD, Turaga SC, Tebo AG, Carandini M, Federico Rossi L, Kleinfeld D, Konnerth A, Svoboda K, Turner GC, Hasseman J, Podgorski K. Glutamate indicators with increased sensitivity and tailored deactivation rates. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2025:2025.03.20.643984. [PMID: 40196590 PMCID: PMC11974752 DOI: 10.1101/2025.03.20.643984] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 04/09/2025]
Abstract
Identifying the input-output operations of neurons requires measurements of synaptic transmission simultaneously at many of a neuron's thousands of inputs in the intact brain. To facilitate this goal, we engineered and screened 3365 variants of the fluorescent protein glutamate indicator iGluSnFR3 in neuron culture, and selected variants in the mouse visual cortex. Two variants have high sensitivity, fast activation (< 2 ms) and deactivation times tailored for recording large populations of synapses (iGluSnFR4s, 153 ms) or rapid dynamics (iGluSnFR4f, 26 ms). By imaging action-potential evoked signals on axons and visually-evoked signals on dendritic spines, we show that iGluSnFR4s/4f primarily detect local synaptic glutamate with single-vesicle sensitivity. The indicators detect a wide range of naturalistic synaptic transmission, including in the vibrissal cortex layer 4 and in hippocampal CA1 dendrites. iGluSnFR4 increases the sensitivity and scale (4s) or speed (4f) of tracking information flow in neural networks in vivo.
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Affiliation(s)
- Abhi Aggarwal
- Allen Institute for Neural Dynamics, Seattle, Washington, USA
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, Virginia, USA
- University of Calgary Cumming School of Medicine and Hotchkiss Brain Institute, Calgary, Alberta, Canada
| | - Adrian Negrean
- Allen Institute for Neural Dynamics, Seattle, Washington, USA
| | - Yang Chen
- Institute of Neuroscience and Munich Cluster for Systems Neurology, Technical University of Munich, Munich, Germany
| | - Rishyashring Iyer
- Department of Physics, University of California, San Diego, La Jolla, California, USA
| | - Daniel Reep
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, Virginia, USA
- The GENIE Project Team
| | - Anyi Liu
- University College London, Gower St, London, United Kingdom
| | - Anirudh Palutla
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, Virginia, USA
| | - Michael E. Xie
- Allen Institute for Neural Dynamics, Seattle, Washington, USA
- Johns Hopkins University, Baltimore, MD, USA
| | | | | | - Lucas W. Kinsey
- Allen Institute for Neural Dynamics, Seattle, Washington, USA
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, Virginia, USA
| | - Julianna L. Sun
- Neuronal Cell Biology Division, Department of Developmental Neurobiology, St. Jude Children’s Research Hospital, Memphis, TN, USA
| | - Pantong Yao
- Department of Neurosciences, University of California, San Diego, La Jolla, California, USA
| | - Jihong Zheng
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, Virginia, USA
- The GENIE Project Team
| | - Arthur Tsang
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, Virginia, USA
- The GENIE Project Team
| | - Getahun Tsegaye
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, Virginia, USA
- The GENIE Project Team
| | - Yonghai Zhang
- Institute of Neuroscience and Munich Cluster for Systems Neurology, Technical University of Munich, Munich, Germany
| | - Ronak H. Patel
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, Virginia, USA
| | - Benjamin J. Arthur
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, Virginia, USA
| | - Julien Hiblot
- Max Planck Institute for Medical Research, Heidelberg, Germany
| | - Philipp Leippe
- CeMM Research Center for Molecular Medicine of the Austrian Academy of Sciences, Wien, Austria
| | | | - Jonathan S. Marvin
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, Virginia, USA
| | - Jason D. Vevea
- Neuronal Cell Biology Division, Department of Developmental Neurobiology, St. Jude Children’s Research Hospital, Memphis, TN, USA
| | - Srinivas C. Turaga
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, Virginia, USA
| | - Alison G. Tebo
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, Virginia, USA
| | | | - L. Federico Rossi
- University College London, Gower St, London, United Kingdom
- Center for Neuroscience and Cognitive Systems, Italian Institute of Technology, Rovereto, Italy
| | - David Kleinfeld
- Department of Physics, University of California, San Diego, La Jolla, California, USA
- Department of Neurobiology, University of California, San Diego, La Jolla, California, USA
| | - Arthur Konnerth
- Institute of Neuroscience and Munich Cluster for Systems Neurology, Technical University of Munich, Munich, Germany
| | - Karel Svoboda
- Allen Institute for Neural Dynamics, Seattle, Washington, USA
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, Virginia, USA
| | - Glenn C. Turner
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, Virginia, USA
- The GENIE Project Team
| | - Jeremy Hasseman
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, Virginia, USA
- The GENIE Project Team
| | - Kaspar Podgorski
- Allen Institute for Neural Dynamics, Seattle, Washington, USA
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, Virginia, USA
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3
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Jafri H, Thomas SJ, Yang SH, Cain RE, Dalva MB. Nano-organization of synapses defines synaptic release properties at cortical neuron dendritic spines. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2025:2025.02.13.637710. [PMID: 39990496 PMCID: PMC11844459 DOI: 10.1101/2025.02.13.637710] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 02/25/2025]
Abstract
Visualization of the submicron organization of excitatory synapses has revealed an unexpectedly ordered architecture consisting of nanocolumns of synaptic proteins that group into nanomodules which scale in number as spine size increases. How these features are related to synaptic function has remained unclear. Here, using super-resolution followed by live-cell line-scan imaging, we find that the size of the smallest miniature calcium and glutamate events are the same, regardless of whether spines have one or two nanopuncta of PSD-95, and that miniature synaptic response in all spines are best fit by a three term Poisson. Two nanomodule spines exhibit more large events without a significant change in event frequency, with the number of the largest events increasing disproportionately. These data support a model where nanomodules define sites of synaptic release and where the nanoarchitecture of synaptic proteins specifies subtypes of excitatory synapses, with increasing numbers of nanomodules increasing coordinated multivesicular release.
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Affiliation(s)
- Haani Jafri
- Department of Neuroscience and Jefferson Synaptic Biology Center, Sidney Kimmel Medical College at Thomas Jefferson University, 233 South 10 Street, Bluemle Life Sciences Building, Room 324, Philadelphia, PA 19107, USA
| | - Samantha J Thomas
- Department of Neuroscience and Jefferson Synaptic Biology Center, Sidney Kimmel Medical College at Thomas Jefferson University, 233 South 10 Street, Bluemle Life Sciences Building, Room 324, Philadelphia, PA 19107, USA
| | - Sung Hoon Yang
- Department of Neuroscience and Jefferson Synaptic Biology Center, Sidney Kimmel Medical College at Thomas Jefferson University, 233 South 10 Street, Bluemle Life Sciences Building, Room 324, Philadelphia, PA 19107, USA
| | - Rachel E Cain
- Department of Neuroscience and Jefferson Synaptic Biology Center, Sidney Kimmel Medical College at Thomas Jefferson University, 233 South 10 Street, Bluemle Life Sciences Building, Room 324, Philadelphia, PA 19107, USA
| | - Matthew B Dalva
- Department of Neuroscience and Jefferson Synaptic Biology Center, Sidney Kimmel Medical College at Thomas Jefferson University, 233 South 10 Street, Bluemle Life Sciences Building, Room 324, Philadelphia, PA 19107, USA
- Tulane Brain Institute, Department of Cell and Molecular Biology, Tulane University, 202 Flower Hall, 6823 St. Charles Avenue, New Orleans, LA 70124, USA
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4
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Barlow ST, Levy AD, Contreras M, Anderson MC, Blanpied TA. Dissecting the functional heterogeneity of glutamatergic synapses with high-throughput optical physiology. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.12.23.629904. [PMID: 39763981 PMCID: PMC11703220 DOI: 10.1101/2024.12.23.629904] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/12/2025]
Abstract
Fluorescent reporters for glutamate release and postsynaptic Ca2+ signaling are essential tools for quantifying synapse functional heterogeneity across neurons and circuits. However, leveraging these probes for neuroscience requires scalable experimental frameworks. Here, we devised a high-throughput approach to efficiently collect and analyze hundreds of optical recordings of glutamate release activity at presynaptic boutons in cultured rat hippocampal neurons. Boutons exhibited remarkable functional heterogeneity and could be separated into multiple functional classes based on their iGluSnFR3 responses to single action potentials, paired stimuli, and synaptic parameters derived from mean-variance analysis. Finally, we developed a novel all-optical assay of pre- and postsynaptic glutamatergic synapse function. We deployed iGluSnFR3 with a red-shifted, postsynaptically-targeted Ca2+ sensor, enabling direct imaging and analysis of NMDA receptor-mediated synaptic transmission at large numbers of dendritic spines. This work enables direct observation of the flow of information at single synapses and should speed detailed investigations of synaptic functional heterogeneity.
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Affiliation(s)
- Samuel T Barlow
- Department of Physiology, University of Maryland School of Medicine, Baltimore, MD 21201, USA
- UM-MIND, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Aaron D Levy
- Department of Physiology, University of Maryland School of Medicine, Baltimore, MD 21201, USA
- UM-MIND, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Minerva Contreras
- Department of Physiology, University of Maryland School of Medicine, Baltimore, MD 21201, USA
- UM-MIND, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Michael C Anderson
- Program in Neuroscience, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Thomas A Blanpied
- Department of Physiology, University of Maryland School of Medicine, Baltimore, MD 21201, USA
- UM-MIND, University of Maryland School of Medicine, Baltimore, MD 21201, USA
- Program in Neuroscience, University of Maryland School of Medicine, Baltimore, MD 21201, USA
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5
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Reshetniak S, Bogaciu CA, Bonn S, Brose N, Cooper BH, D'Este E, Fauth M, Fernández-Busnadiego R, Fiosins M, Fischer A, Georgiev SV, Jakobs S, Klumpp S, Köster S, Lange F, Lipstein N, Macarrón-Palacios V, Milovanovic D, Moser T, Müller M, Opazo F, Outeiro TF, Pape C, Priesemann V, Rehling P, Salditt T, Schlüter O, Simeth N, Steinem C, Tchumatchenko T, Tetzlaff C, Tirard M, Urlaub H, Wichmann C, Wolf F, Rizzoli SO. The synaptic vesicle cluster as a controller of pre- and postsynaptic structure and function. J Physiol 2024. [PMID: 39367860 DOI: 10.1113/jp286400] [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: 06/12/2024] [Accepted: 09/11/2024] [Indexed: 10/07/2024] Open
Abstract
The synaptic vesicle cluster (SVC) is an essential component of chemical synapses, which provides neurotransmitter-loaded vesicles during synaptic activity, at the same time as also controlling the local concentrations of numerous exo- and endocytosis cofactors. In addition, the SVC hosts molecules that participate in other aspects of synaptic function, from cytoskeletal components to adhesion proteins, and affects the location and function of organelles such as mitochondria and the endoplasmic reticulum. We argue here that these features extend the functional involvement of the SVC in synapse formation, signalling and plasticity, as well as synapse stabilization and metabolism. We also propose that changes in the size of the SVC coalesce with changes in the postsynaptic compartment, supporting the interplay between pre- and postsynaptic dynamics. Thereby, the SVC could be seen as an 'all-in-one' regulator of synaptic structure and function, which should be investigated in more detail, to reveal molecular mechanisms that control synaptic function and heterogeneity.
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Affiliation(s)
- Sofiia Reshetniak
- Institute for Neuro- and Sensory Physiology and Biostructural Imaging of Neurodegeneration (BIN) Center, University Medical Center Göttingen, Göttingen, Germany
| | - Cristian A Bogaciu
- Institute for Neuro- and Sensory Physiology and Biostructural Imaging of Neurodegeneration (BIN) Center, University Medical Center Göttingen, Göttingen, Germany
| | - Stefan Bonn
- Institute of Medical Systems Biology, Center for Molecular Neurobiology Hamburg, Hamburg, Germany
| | - Nils Brose
- Department of Molecular Neurobiology, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany
- Cluster of Excellence "Multiscale Bioimaging: from Molecular Machines to Networks of Excitable Cells" (MBExC), University of Göttingen, Göttingen, Germany
| | - Benjamin H Cooper
- Department of Molecular Neurobiology, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany
| | - Elisa D'Este
- Optical Microscopy Facility, Max Planck Institute for Medical Research, Heidelberg, Germany
| | - Michael Fauth
- Georg-August-University Göttingen, Faculty of Physics, Institute for the Dynamics of Complex Systems, Friedrich-Hund-Platz 1, Göttingen, Germany
| | - Rubén Fernández-Busnadiego
- Institute of Neuropathology, University Medical Center Göttingen, Göttingen, Germany
- Cluster of Excellence "Multiscale Bioimaging: from Molecular Machines to Networks of Excitable Cells" (MBExC), University of Göttingen, Göttingen, Germany
| | - Maksims Fiosins
- Leibniz-Forschungsinstitut für Molekulare Pharmakologie, Berlin, Germany
| | - André Fischer
- German Center for Neurodegenerative Diseases, Göttingen, Germany
- Cluster of Excellence "Multiscale Bioimaging: from Molecular Machines to Networks of Excitable Cells" (MBExC), University of Göttingen, Göttingen, Germany
| | - Svilen V Georgiev
- Institute for Neuro- and Sensory Physiology and Biostructural Imaging of Neurodegeneration (BIN) Center, University Medical Center Göttingen, Göttingen, Germany
| | - Stefan Jakobs
- Research Group Structure and Dynamics of Mitochondria, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany
- Cluster of Excellence "Multiscale Bioimaging: from Molecular Machines to Networks of Excitable Cells" (MBExC), University of Göttingen, Göttingen, Germany
| | - Stefan Klumpp
- Theoretical Biophysics Group, Institute for the Dynamics of Complex Systems, Georg-August University Göttingen, Göttingen, Germany
| | - Sarah Köster
- Institute for X-Ray Physics, Georg-August University Göttingen, Göttingen, Germany
- Cluster of Excellence "Multiscale Bioimaging: from Molecular Machines to Networks of Excitable Cells" (MBExC), University of Göttingen, Göttingen, Germany
| | - Felix Lange
- Research Group Structure and Dynamics of Mitochondria, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany
| | - Noa Lipstein
- Leibniz-Forschungsinstitut für Molekulare Pharmakologie, Berlin, Germany
| | | | - Dragomir Milovanovic
- Laboratory of Molecular Neuroscience, German Center for Neurodegenerative Diseases, Berlin, Germany
| | - Tobias Moser
- Institute for Auditory Neuroscience, University Medical Center Göttingen, Göttingen, Germany
- Cluster of Excellence "Multiscale Bioimaging: from Molecular Machines to Networks of Excitable Cells" (MBExC), University of Göttingen, Göttingen, Germany
| | - Marcus Müller
- Institute for Theoretical Physics, Georg-August University Göttingen, Göttingen, Germany
| | - Felipe Opazo
- Institute for Neuro- and Sensory Physiology and Biostructural Imaging of Neurodegeneration (BIN) Center, University Medical Center Göttingen, Göttingen, Germany
| | - Tiago F Outeiro
- Department of Experimental Neurodegeneration, Center for Biostructural Imaging of Neurodegeneration, University Medical Center Göttingen, Göttingen, Germany
| | - Constantin Pape
- Institute of Computer Science, Georg-August University Göttingen, Göttingen, Germany
| | - Viola Priesemann
- Georg-August-University Göttingen, Faculty of Physics, Institute for the Dynamics of Complex Systems, Friedrich-Hund-Platz 1, Göttingen, Germany
- Max-Planck Institute for Dynamics and Self-Organization, Am Fassberg 17, Göttingen, Germany
- Cluster of Excellence "Multiscale Bioimaging: from Molecular Machines to Networks of Excitable Cells" (MBExC), University of Göttingen, Göttingen, Germany
| | - Peter Rehling
- Department of Cellular Biochemistry, University Medical Center Göttingen, Göttingen, Germany
- Cluster of Excellence "Multiscale Bioimaging: from Molecular Machines to Networks of Excitable Cells" (MBExC), University of Göttingen, Göttingen, Germany
| | - Tim Salditt
- Institute for X-Ray Physics, Georg-August University Göttingen, Göttingen, Germany
- Cluster of Excellence "Multiscale Bioimaging: from Molecular Machines to Networks of Excitable Cells" (MBExC), University of Göttingen, Göttingen, Germany
| | - Oliver Schlüter
- Clinic for Psychiatry and Psychotherapy, University Medical Center Göttingen, Göttingen, Germany
| | - Nadja Simeth
- Institute of Organic and Biomolecular Chemistry, Georg-August University Göttingen, Göttingen, Germany
- Cluster of Excellence "Multiscale Bioimaging: from Molecular Machines to Networks of Excitable Cells" (MBExC), University of Göttingen, Göttingen, Germany
| | - Claudia Steinem
- Institute of Organic and Biomolecular Chemistry, Georg-August University Göttingen, Göttingen, Germany
- Cluster of Excellence "Multiscale Bioimaging: from Molecular Machines to Networks of Excitable Cells" (MBExC), University of Göttingen, Göttingen, Germany
| | - Tatjana Tchumatchenko
- Institute of Experimental Epileptology and Cognition Research, University of Bonn Medical Center, Bonn, Germany
| | - Christian Tetzlaff
- Institute for Neuro- and Sensory Physiology and Biostructural Imaging of Neurodegeneration (BIN) Center, University Medical Center Göttingen, Göttingen, Germany
| | - Marilyn Tirard
- Department of Molecular Neurobiology, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany
| | - Henning Urlaub
- Bioanalytical Mass Spectrometry, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany
| | - Carolin Wichmann
- Institute for Auditory Neuroscience University Medical Center Göttingen, Göttingen, Germany
- Biostructural Imaging of Neurodegeneration (BIN) Center, University Medical Center Göttingen, Göttingen, Germany
| | - Fred Wolf
- Max-Planck-Institute for Dynamics and Self-Organization, 37077 Göttingen and Institute for Dynamics of Biological Networks, Georg-August University Göttingen, Göttingen, Germany
| | - Silvio O Rizzoli
- Institute for Neuro- and Sensory Physiology and Biostructural Imaging of Neurodegeneration (BIN) Center, University Medical Center Göttingen, Göttingen, Germany
- Cluster of Excellence "Multiscale Bioimaging: from Molecular Machines to Networks of Excitable Cells" (MBExC), University of Göttingen, Göttingen, Germany
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6
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Passlick S, Ullah G, Henneberger C. Bidirectional dysregulation of synaptic glutamate signaling after transient metabolic failure. eLife 2024; 13:RP98834. [PMID: 39287515 PMCID: PMC11407764 DOI: 10.7554/elife.98834] [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: 09/19/2024] Open
Abstract
Ischemia leads to a severe dysregulation of glutamate homeostasis and excitotoxic cell damage in the brain. Shorter episodes of energy depletion, for instance during peri-infarct depolarizations, can also acutely perturb glutamate signaling. It is less clear if such episodes of metabolic failure also have persistent effects on glutamate signaling and how the relevant mechanisms such as glutamate release and uptake are differentially affected. We modeled acute and transient metabolic failure by using a chemical ischemia protocol and analyzed its effect on glutamatergic synaptic transmission and extracellular glutamate signals by electrophysiology and multiphoton imaging, respectively, in the mouse hippocampus. Our experiments uncover a duration-dependent bidirectional dysregulation of glutamate signaling. Whereas short chemical ischemia induces a lasting potentiation of presynaptic glutamate release and synaptic transmission, longer episodes result in a persistent postsynaptic failure of synaptic transmission. We also observed unexpected differences in the vulnerability of the investigated cellular mechanisms. Axonal action potential firing and glutamate uptake were surprisingly resilient compared to postsynaptic cells, which overall were most vulnerable to acute and transient metabolic stress. We conclude that short perturbations of energy supply lead to a lasting potentiation of synaptic glutamate release, which may increase glutamate excitotoxicity well beyond the metabolic incident.
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Affiliation(s)
- Stefan Passlick
- Institute of Cellular Neurosciences, Medical Faculty, University of BonnBonnGermany
| | - Ghanim Ullah
- Department of Physics, University of South FloridaTampaUnited States
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7
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Bär J, Fanutza T, Reimann CC, Seipold L, Grohe M, Bolter JR, Delfs F, Bucher M, Gee CE, Schweizer M, Saftig P, Mikhaylova M. Non-canonical function of ADAM10 in presynaptic plasticity. Cell Mol Life Sci 2024; 81:342. [PMID: 39123091 PMCID: PMC11335265 DOI: 10.1007/s00018-024-05327-8] [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: 02/20/2024] [Revised: 06/07/2024] [Accepted: 06/17/2024] [Indexed: 08/12/2024]
Abstract
A Disintegrin And Metalloproteinase 10 (ADAM10) plays a pivotal role in shaping neuronal networks by orchestrating the activity of numerous membrane proteins through the shedding of their extracellular domains. Despite its significance in the brain, the specific cellular localization of ADAM10 remains not well understood due to a lack of appropriate tools. Here, using a specific ADAM10 antibody suitable for immunostainings, we observed that ADAM10 is localized to presynapses and especially enriched at presynaptic vesicles of mossy fiber (MF)-CA3 synapses in the hippocampus. These synapses undergo pronounced frequency facilitation of neurotransmitter release, a process that play critical roles in information transfer and neural computation. We demonstrate, that in conditional ADAM10 knockout mice the ability of MF synapses to undergo this type of synaptic plasticity is greatly reduced. The loss of facilitation depends on the cytosolic domain of ADAM10 and association with the calcium sensor synaptotagmin 7 rather than ADAM10's proteolytic activity. Our findings unveil a new role of ADAM10 in the regulation of synaptic vesicle exocytosis.
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Affiliation(s)
- Julia Bär
- AG Optobiology, Institute of Biology, Humboldt Universität Zu Berlin, 10115, Berlin, Germany
- Guest Group, "Neuronal Protein Transport", Center for Molecular Neurobiology, University Medical Center Hamburg-Eppendorf, 20251, Hamburg, Germany
| | - Tomas Fanutza
- AG Optobiology, Institute of Biology, Humboldt Universität Zu Berlin, 10115, Berlin, Germany
- Guest Group, "Neuronal Protein Transport", Center for Molecular Neurobiology, University Medical Center Hamburg-Eppendorf, 20251, Hamburg, Germany
| | - Christopher C Reimann
- Guest Group, "Neuronal Protein Transport", Center for Molecular Neurobiology, University Medical Center Hamburg-Eppendorf, 20251, Hamburg, Germany
| | - Lisa Seipold
- Biochemisches Institut, Christian Albrechts-Universität Kiel, 24098, Kiel, Germany
| | - Maja Grohe
- Biochemisches Institut, Christian Albrechts-Universität Kiel, 24098, Kiel, Germany
| | - Janike Rabea Bolter
- AG Optobiology, Institute of Biology, Humboldt Universität Zu Berlin, 10115, Berlin, Germany
| | - Flemming Delfs
- Guest Group, "Neuronal Protein Transport", Center for Molecular Neurobiology, University Medical Center Hamburg-Eppendorf, 20251, Hamburg, Germany
| | - Michael Bucher
- Guest Group, "Neuronal Protein Transport", Center for Molecular Neurobiology, University Medical Center Hamburg-Eppendorf, 20251, Hamburg, Germany
| | - Christine E Gee
- Department of Synaptic Physiology, Center for Molecular Neurobiology, ZMNH, University Medical Center Hamburg-Eppendorf, 20251, Hamburg, Germany
| | - Michaela Schweizer
- Morphology and Electron Microscopy, Center for Molecular Neurobiology, University Medical Center Hamburg-Eppendorf, ZMNH, 20251, Hamburg, Germany
| | - Paul Saftig
- Biochemisches Institut, Christian Albrechts-Universität Kiel, 24098, Kiel, Germany.
| | - Marina Mikhaylova
- AG Optobiology, Institute of Biology, Humboldt Universität Zu Berlin, 10115, Berlin, Germany.
- Guest Group, "Neuronal Protein Transport", Center for Molecular Neurobiology, University Medical Center Hamburg-Eppendorf, 20251, Hamburg, Germany.
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8
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Passlick S, Ullah G, Henneberger C. Bidirectional dysregulation of synaptic glutamate signaling after transient metabolic failure. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.04.11.588988. [PMID: 38645213 PMCID: PMC11030306 DOI: 10.1101/2024.04.11.588988] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/23/2024]
Abstract
Ischemia leads to a severe dysregulation of glutamate homeostasis and excitotoxic cell damage in the brain. Shorter episodes of energy depletion, for instance during peri-infarct depolarizations, can also acutely perturb glutamate signaling. It is less clear if such episodes of metabolic failure also have persistent effects on glutamate signaling and how the relevant mechanisms such as glutamate release and uptake are differentially affected. We modelled acute and transient metabolic failure by using a chemical ischemia protocol and analyzed its effect on glutamatergic synaptic transmission and extracellular glutamate signals by electrophysiology and multiphoton imaging, respectively, in the hippocampus. Our experiments uncover a duration-dependent bidirectional dysregulation of glutamate signaling. Whereas short chemical ischemia induces a lasting potentiation of presynaptic glutamate release and synaptic transmission, longer episodes result in a persistent postsynaptic failure of synaptic transmission. We also observed unexpected differences in the vulnerability of the investigated cellular mechanisms. Axonal action potential firing and glutamate uptake were unexpectedly resilient compared to postsynaptic cells, which overall were most vulnerable to acute and transient metabolic stress. We conclude that even short perturbations of energy supply lead to a lasting potentiation of synaptic glutamate release, which may increase glutamate excitotoxicity well beyond the metabolic incident.
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9
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Rijal K, Müller NIC, Friauf E, Singh A, Prasad A, Das D. Exact Distribution of the Quantal Content in Synaptic Transmission. PHYSICAL REVIEW LETTERS 2024; 132:228401. [PMID: 38877921 PMCID: PMC11571698 DOI: 10.1103/physrevlett.132.228401] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/19/2023] [Revised: 01/26/2024] [Accepted: 04/25/2024] [Indexed: 08/23/2024]
Abstract
During electrochemical signal transmission through synapses, triggered by an action potential (AP), a stochastic number of synaptic vesicles (SVs), called the "quantal content," release neurotransmitters in the synaptic cleft. It is widely accepted that the quantal content probability distribution is a binomial based on the number of ready-release SVs in the presynaptic terminal. But the latter number itself fluctuates due to its stochastic replenishment, hence the actual distribution of quantal content is unknown. We show that exact distribution of quantal content can be derived for general stochastic AP inputs in the steady state. For fixed interval AP train, we prove that the distribution is a binomial, and corroborate our predictions by comparison with electrophysiological recordings from MNTB-LSO synapses of juvenile mice. For a Poisson train, we show that the distribution is nonbinomial. Moreover, we find exact moments of the quantal content in the Poisson and other general cases, which may be used to obtain the model parameters from experiments.
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Affiliation(s)
- Krishna Rijal
- Department of Physics, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India
| | - Nicolas I. C. Müller
- Animal Physiology Group, Department of Biology, University of Kaiserslautern, Kaiserslautern, Germany
| | - Eckhard Friauf
- Animal Physiology Group, Department of Biology, University of Kaiserslautern, Kaiserslautern, Germany
| | - Abhyudai Singh
- Departments of Electrical and Computer Engineering, Biomedical Engineering and Mathematical Sciences, University of Delaware, Newark, Delaware 19716, USA
| | - Ashok Prasad
- Department of Chemical and Biological Engineering, Colorado State University, Fort Collins, Colorado, USA
| | - Dibyendu Das
- Department of Physics, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India
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10
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Rohner VL, Lamothe-Molina PJ, Patriarchi T. Engineering, applications, and future perspectives of GPCR-based genetically encoded fluorescent indicators for neuromodulators. J Neurochem 2024; 168:163-184. [PMID: 38288673 DOI: 10.1111/jnc.16045] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2023] [Revised: 12/20/2023] [Accepted: 12/22/2023] [Indexed: 02/23/2024]
Abstract
This review explores the evolving landscape of G-protein-coupled receptor (GPCR)-based genetically encoded fluorescent indicators (GEFIs), with a focus on their development, structural components, engineering strategies, and applications. We highlight the unique features of this indicator class, emphasizing the importance of both the sensing domain (GPCR structure and activation mechanism) and the reporting domain (circularly permuted fluorescent protein (cpFP) structure and fluorescence modulation). Further, we discuss indicator engineering approaches, including the selection of suitable cpFPs and expression systems. Additionally, we showcase the diversity and flexibility of their application by presenting a summary of studies where such indicators were used. Along with all the advantages, we also focus on the current limitations as well as common misconceptions that arise when using these indicators. Finally, we discuss future directions in indicator engineering, including strategies for screening with increased throughput, optimization of the ligand-binding properties, structural insights, and spectral diversity.
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Affiliation(s)
- Valentin Lu Rohner
- Institute of Pharmacology and Toxicology, University of Zürich, Zürich, Switzerland
| | | | - Tommaso Patriarchi
- Institute of Pharmacology and Toxicology, University of Zürich, Zürich, Switzerland
- Neuroscience Center Zurich, University and ETH Zurich, Zurich, Switzerland
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11
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Friedenberger Z, Harkin E, Tóth K, Naud R. Silences, spikes and bursts: Three-part knot of the neural code. J Physiol 2023; 601:5165-5193. [PMID: 37889516 DOI: 10.1113/jp281510] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2023] [Accepted: 09/28/2023] [Indexed: 10/28/2023] Open
Abstract
When a neuron breaks silence, it can emit action potentials in a number of patterns. Some responses are so sudden and intense that electrophysiologists felt the need to single them out, labelling action potentials emitted at a particularly high frequency with a metonym - bursts. Is there more to bursts than a figure of speech? After all, sudden bouts of high-frequency firing are expected to occur whenever inputs surge. The burst coding hypothesis advances that the neural code has three syllables: silences, spikes and bursts. We review evidence supporting this ternary code in terms of devoted mechanisms for burst generation, synaptic transmission and synaptic plasticity. We also review the learning and attention theories for which such a triad is beneficial.
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Affiliation(s)
- Zachary Friedenberger
- Brain and Mind Institute, Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, Ontario, Canada
- Centre for Neural Dynamics and Artifical Intelligence, Department of Physics, University of Ottawa, Ottawa, Ontario, Ottawa
| | - Emerson Harkin
- Brain and Mind Institute, Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, Ontario, Canada
| | - Katalin Tóth
- Brain and Mind Institute, Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, Ontario, Canada
| | - Richard Naud
- Brain and Mind Institute, Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, Ontario, Canada
- Centre for Neural Dynamics and Artifical Intelligence, Department of Physics, University of Ottawa, Ottawa, Ontario, Ottawa
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12
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Madar A, Dong C, Sheffield M. BTSP, not STDP, Drives Shifts in Hippocampal Representations During Familiarization. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.10.17.562791. [PMID: 37904999 PMCID: PMC10614909 DOI: 10.1101/2023.10.17.562791] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/02/2023]
Abstract
Synaptic plasticity is widely thought to support memory storage in the brain, but the rules determining impactful synaptic changes in-vivo are not known. We considered the trial-by-trial shifting dynamics of hippocampal place fields (PFs) as an indicator of ongoing plasticity during memory formation. By implementing different plasticity rules in computational models of spiking place cells and comparing to experimentally measured PFs from mice navigating familiar and novel environments, we found that Behavioral-Timescale-Synaptic-Plasticity (BTSP), rather than Hebbian Spike-Timing-Dependent-Plasticity, is the principal mechanism governing PF shifting dynamics. BTSP-triggering events are rare, but more frequent during novel experiences. During exploration, their probability is dynamic: it decays after PF onset, but continually drives a population-level representational drift. Finally, our results show that BTSP occurs in CA3 but is less frequent and phenomenologically different than in CA1. Overall, our study provides a new framework to understand how synaptic plasticity shapes neuronal representations during learning.
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Affiliation(s)
- A.D. Madar
- Department of Neurobiology, Neuroscience Institute, University of Chicago
| | - C. Dong
- Department of Neurobiology, Neuroscience Institute, University of Chicago
- current affiliation: Department of Neurobiology, Stanford University School of Medicine
| | - M.E.J. Sheffield
- Department of Neurobiology, Neuroscience Institute, University of Chicago
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Lumeij LB, van Huijstee AN, Cappaert NLM, Kessels HW. Variance analysis as a method to predict the locus of plasticity at populations of non-uniform synapses. Front Cell Neurosci 2023; 17:1232541. [PMID: 37528963 PMCID: PMC10388551 DOI: 10.3389/fncel.2023.1232541] [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: 05/31/2023] [Accepted: 06/30/2023] [Indexed: 08/03/2023] Open
Abstract
Our knowledge on synaptic transmission in the central nervous system has often been obtained by evoking synaptic responses to populations of synapses. Analysis of the variance in synaptic responses can be applied as a method to predict whether a change in synaptic responses is a consequence of altered presynaptic neurotransmitter release or postsynaptic receptors. However, variance analysis is based on binomial statistics, which assumes that synapses are uniform. In reality, synapses are far from uniform, which questions the reliability of variance analysis when applying this method to populations of synapses. To address this, we used an in silico model for evoked synaptic responses and compared variance analysis outcomes between populations of uniform versus non-uniform synapses. This simulation revealed that variance analysis produces similar results irrespectively of the grade of uniformity of synapses. We put this variance analysis to the test with an electrophysiology experiment using a model system for which the loci of plasticity are well established: the effect of amyloid-β on synapses. Variance analysis correctly predicted that postsynaptically produced amyloid-β triggered predominantly a loss of synapses and a minor reduction of postsynaptic currents in remaining synapses with little effect on presynaptic release probability. We propose that variance analysis can be reliably used to predict the locus of synaptic changes for populations of non-uniform synapses.
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Martínez San Segundo P, Terni B, Llobet A. Multivesicular release favors short term synaptic depression in hippocampal autapses. Front Cell Neurosci 2023; 17:1057242. [PMID: 37265578 PMCID: PMC10230035 DOI: 10.3389/fncel.2023.1057242] [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: 09/29/2022] [Accepted: 04/10/2023] [Indexed: 06/03/2023] Open
Abstract
Presynaptic terminals of the central nervous system can support univesicular and multivesicular synchronous release of neurotransmitters, however, the functional implications of the prevalence of one mechanism over the other are yet unresolved. Here, we took advantage of the expression of SF-iGluSnFR.S72A in the astrocytic feeder layer of autaptic hippocampal neuronal cultures to associate the liberation of glutamate to excitatory postsynaptic currents. The presence of the glutamate sensor in glial cells avoided any interference with the function of endogenous postsynaptic receptors. It was possible to optically detect changes in neurotransmitter release probability, which was heterogeneous among synaptic boutons studied. For each neuron investigated, the liberation of neurotransmitters occurred through a predominant mechanism. The prevalence of multivesicular over univesicular release increased synaptic strength and enhanced short-term synaptic depression. These results show that the preference of hippocampal boutons to synchronously release one or more vesicles determines the strength and low pass filtering properties of the synapses established.
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Affiliation(s)
- Pablo Martínez San Segundo
- Laboratory of Neurobiology, Department of Pathology and Experimental Therapy, Institute of Neurosciences, University of Barcelona, Barcelona, Spain
- Bellvitge Biomedical Research Institute (IDIBELL), Barcelona, Spain
| | - Beatrice Terni
- Laboratory of Neurobiology, Department of Pathology and Experimental Therapy, Institute of Neurosciences, University of Barcelona, Barcelona, Spain
- Bellvitge Biomedical Research Institute (IDIBELL), Barcelona, Spain
| | - Artur Llobet
- Laboratory of Neurobiology, Department of Pathology and Experimental Therapy, Institute of Neurosciences, University of Barcelona, Barcelona, Spain
- Bellvitge Biomedical Research Institute (IDIBELL), Barcelona, Spain
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15
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Malagon G, Myeong J, Klyachko VA. Two forms of asynchronous release with distinctive spatiotemporal dynamics in central synapses. eLife 2023; 12:e84041. [PMID: 37166282 PMCID: PMC10174687 DOI: 10.7554/elife.84041] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2022] [Accepted: 04/24/2023] [Indexed: 05/12/2023] Open
Abstract
Asynchronous release is a ubiquitous form of neurotransmitter release that persists for tens to hundreds of milliseconds after an action potential. How asynchronous release is organized and regulated at the synaptic active zone (AZ) remains debatable. Using nanoscale-precision imaging of individual release events in rat hippocampal synapses, we observed two spatially distinct subpopulations of asynchronous events, ~75% of which occurred inside the AZ and with a bias towards the AZ center, while ~25% occurred outside of the functionally defined AZ, that is, ectopically. The two asynchronous event subpopulations also differed from each other in temporal properties, with ectopic events occurring at significantly longer time intervals from synchronous events than the asynchronous events inside the AZ. Both forms of asynchronous release did not, to a large extent, utilize the same release sites as synchronous events. The two asynchronous event subpopulations also differ from synchronous events in some aspects of exo-endocytosis coupling, particularly in the contribution from the fast calcium-dependent endocytosis. These results identify two subpopulations of asynchronous release events with distinctive organization and spatiotemporal dynamics.
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Affiliation(s)
- Gerardo Malagon
- Department of Cell Biology and Physiology, Washington University School of MedicineSt LouisUnited States
| | - Jongyun Myeong
- Department of Cell Biology and Physiology, Washington University School of MedicineSt LouisUnited States
| | - Vitaly A Klyachko
- Department of Cell Biology and Physiology, Washington University School of MedicineSt LouisUnited States
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Bykhovskaia M. Probabilities of evoked and spontaneous synaptic transmission at individual active zones: Lessons from Drosophila. Front Mol Neurosci 2023; 15:1110538. [PMID: 36683858 PMCID: PMC9846329 DOI: 10.3389/fnmol.2022.1110538] [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: 11/28/2022] [Accepted: 12/12/2022] [Indexed: 01/05/2023] Open
Abstract
Nerve terminals release neuronal transmitters at morphological specializations known as active zones (AZs). Synaptic vesicle fusion at individual AZs is probabilistic, and this property is fundamental for the neuronal information transfer. Until recently, a lack of appropriate tools limited the studies of stochastic properties of neuronal secretion at individual AZs. However, Drosophila transgenic lines that express postsynaptically tethered Ca2+ sensor GCaMP enabled the visualization of single exocytic event at individual AZs. The present mini-review discusses how this powerful approach enables the investigation of the evoked and spontaneous transmission at single AZs and promotes the understanding of the properties of both release components.
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17
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James B, Piekarz P, Moya-Díaz J, Lagnado L. The Impact of Multivesicular Release on the Transmission of Sensory Information by Ribbon Synapses. J Neurosci 2022; 42:9401-9414. [PMID: 36344266 PMCID: PMC9794368 DOI: 10.1523/jneurosci.0717-22.2022] [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: 04/11/2022] [Revised: 10/01/2022] [Accepted: 10/06/2022] [Indexed: 11/09/2022] Open
Abstract
The statistics of vesicle release determine how synapses transfer information, but the classical Poisson model of independent release does not always hold at the first stages of vision and hearing. There, ribbon synapses also encode sensory signals as events comprising two or more vesicles released simultaneously. The implications of such coordinated multivesicular release (MVR) for spike generation are not known. Here we investigate how MVR alters the transmission of sensory information compared with Poisson synapses using a pure rate-code. We used leaky integrate-and-fire models incorporating the statistics of release measured experimentally from glutamatergic synapses of retinal bipolar cells in zebrafish (both sexes) and compared these with models assuming Poisson inputs constrained to operate at the same average rates. We find that MVR can increase the number of spikes generated per vesicle while reducing interspike intervals and latency to first spike. The combined effect was to increase the efficiency of information transfer (bits per vesicle) over a range of conditions mimicking target neurons of different size. MVR was most advantageous in neurons with short time constants and reliable synaptic inputs, when less convergence was required to trigger spikes. In the special case of a single input driving a neuron, as occurs in the auditory system of mammals, MVR increased information transfer whenever spike generation required more than one vesicle. This study demonstrates how presynaptic integration of vesicles by MVR can increase the efficiency with which sensory information is transmitted compared with a rate-code described by Poisson statistics.SIGNIFICANCE STATEMENT Neurons communicate by the stochastic release of vesicles at the synapse and the statistics of this process will determine how information is represented by spikes. The classical model is that vesicles are released independently by a Poisson process, but this does not hold at ribbon-type synapses specialized to transmit the first electrical signals in vision and hearing, where two or more vesicles can fuse in a single event by a process termed coordinated multivesicular release. This study shows that multivesicular release can increase the number of spikes generated per vesicle and the efficiency of information transfer (bits per vesicle) over a range of conditions found in the retina and peripheral auditory system.
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Affiliation(s)
- Ben James
- Sussex Neuroscience, School of Life Sciences, University of Sussex, Brighton, BN1 9QG, United Kingdom
| | - Pawel Piekarz
- Sussex Neuroscience, School of Life Sciences, University of Sussex, Brighton, BN1 9QG, United Kingdom
| | - José Moya-Díaz
- Sussex Neuroscience, School of Life Sciences, University of Sussex, Brighton, BN1 9QG, United Kingdom
| | - Leon Lagnado
- Sussex Neuroscience, School of Life Sciences, University of Sussex, Brighton, BN1 9QG, United Kingdom
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18
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Myeong J, Klyachko VA. Rapid astrocyte-dependent facilitation amplifies multi-vesicular release in hippocampal synapses. Cell Rep 2022; 41:111820. [PMID: 36516768 PMCID: PMC9805313 DOI: 10.1016/j.celrep.2022.111820] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2022] [Revised: 09/30/2022] [Accepted: 11/21/2022] [Indexed: 12/15/2022] Open
Abstract
Synaptic facilitation is a major form of short-term plasticity typically driven by an increase in residual presynaptic calcium. Using near-total internal reflection fluorescence (near-TIRF) imaging of single vesicle release in cultured hippocampal synapses, we demonstrate a distinctive, release-dependent form of facilitation in which probability of vesicle release is higher following a successful glutamate release event than following a failure. This phenomenon has an onset of ≤500 ms and lasts several seconds, resulting in clusters of successful release events. The release-dependent facilitation requires neuronal contact with astrocytes and astrocytic glutamate uptake by EAAT1. It is not observed in neurons grown alone or in the presence of astrocyte-conditioned media. This form of facilitation dynamically amplifies multi-vesicular release. Facilitation-evoked release events exhibit spatial clustering and have a preferential localization toward the active zone center. These results uncover a rapid astrocyte-dependent form of facilitation acting via modulation of multi-vesicular release and displaying distinctive spatiotemporal properties.
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Affiliation(s)
- Jongyun Myeong
- Department of Cell Biology and Physiology, Washington University School of Medicine, St. Louis, MO 63132, USA
| | - Vitaly A. Klyachko
- Department of Cell Biology and Physiology, Washington University School of Medicine, St. Louis, MO 63132, USA,Lead contact,Correspondence:
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