1
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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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2
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Rodriguez Gotor JJ, Mahfooz K, Perez-Otano I, Wesseling JF. Parallel processing of quickly and slowly mobilized reserve vesicles in hippocampal synapses. eLife 2024; 12:RP88212. [PMID: 38727712 PMCID: PMC11087054 DOI: 10.7554/elife.88212] [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: 05/12/2024] Open
Abstract
Vesicles within presynaptic terminals are thought to be segregated into a variety of readily releasable and reserve pools. The nature of the pools and trafficking between them is not well understood, but pools that are slow to mobilize when synapses are active are often assumed to feed pools that are mobilized more quickly, in a series. However, electrophysiological studies of synaptic transmission have suggested instead a parallel organization where vesicles within slowly and quickly mobilized reserve pools would separately feed independent reluctant- and fast-releasing subdivisions of the readily releasable pool. Here, we use FM-dyes to confirm the existence of multiple reserve pools at hippocampal synapses and a parallel organization that prevents intermixing between the pools, even when stimulation is intense enough to drive exocytosis at the maximum rate. The experiments additionally demonstrate extensive heterogeneity among synapses in the relative sizes of the slowly and quickly mobilized reserve pools, which suggests equivalent heterogeneity in the numbers of reluctant and fast-releasing readily releasable vesicles that may be relevant for understanding information processing and storage.
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Affiliation(s)
| | - Kashif Mahfooz
- Department of Pharmacology, University of OxfordOxfordUnited Kingdom
| | - Isabel Perez-Otano
- Instituto de Neurociencias de Alicante CSIC-UMHSan Juan de AlicanteSpain
| | - John F Wesseling
- Instituto de Neurociencias de Alicante CSIC-UMHSan Juan de AlicanteSpain
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3
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Tiwari A, Myeong J, Hashemiaghdam A, Zhang H, Niu X, Laramie MA, Stunault MI, Sponagel J, Patti G, Shriver L, Klyachko V, Ashrafi G. Mitochondrial pyruvate transport regulates presynaptic metabolism and neurotransmission. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.03.20.586011. [PMID: 38562794 PMCID: PMC10983914 DOI: 10.1101/2024.03.20.586011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/04/2024]
Abstract
Glucose has long been considered the primary fuel source for the brain. However, glucose levels fluctuate in the brain during sleep, intense circuit activity, or dietary restrictions, posing significant metabolic stress. Here, we demonstrate that the mammalian brain utilizes pyruvate as a fuel source, and pyruvate can support neuronal viability in the absence of glucose. Nerve terminals are sites of metabolic vulnerability within a neuron and we show that mitochondrial pyruvate uptake is a critical step in oxidative ATP production in hippocampal terminals. We find that the mitochondrial pyruvate carrier is post-translationally modified by lysine acetylation which in turn modulates mitochondrial pyruvate uptake. Importantly, our data reveal that the mitochondrial pyruvate carrier regulates distinct steps in synaptic transmission, namely, the spatiotemporal pattern of synaptic vesicle release and the efficiency of vesicle retrieval, functions that have profound implications for synaptic plasticity. In summary, we identify pyruvate as a potent neuronal fuel and mitochondrial pyruvate uptake as a critical node for the metabolic control of synaptic transmission in hippocampal terminals.
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Affiliation(s)
- Anupama Tiwari
- Department of Cell Biology and Physiology, Washington University in St. Louis
| | - Jongyun Myeong
- Department of Cell Biology and Physiology, Washington University in St. Louis
| | - Arsalan Hashemiaghdam
- Department of Cell Biology and Physiology, Washington University in St. Louis
- Present address: Tufts Medical Center, Boston, MA
| | - Hao Zhang
- Department of Chemistry, Department of Medicine, Center for Metabolomics and Isotope Tracing, Washington University in St. Louis
| | - Xianfeng Niu
- Department of Chemistry, Department of Medicine, Center for Metabolomics and Isotope Tracing, Washington University in St. Louis
| | - Marissa A Laramie
- Department of Cell Biology and Physiology, Washington University in St. Louis
| | - Marion I Stunault
- Department of Cell Biology and Physiology, Washington University in St. Louis
| | - Jasmin Sponagel
- Department of Cell Biology and Physiology, Washington University in St. Louis
| | - Gary Patti
- Department of Chemistry, Department of Medicine, Center for Metabolomics and Isotope Tracing, Washington University in St. Louis
| | - Leah Shriver
- Department of Chemistry, Department of Medicine, Center for Metabolomics and Isotope Tracing, Washington University in St. Louis
| | - Vitaly Klyachko
- Department of Cell Biology and Physiology, Washington University in St. Louis
| | - Ghazaleh Ashrafi
- Department of Cell Biology and Physiology, Washington University in St. Louis
- Needleman Center for Neurometabolism and Axonal Therapeutics, Washington University in St. Louis
- Lead Contact
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4
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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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5
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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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6
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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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7
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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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8
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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: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2022] [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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9
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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: 5] [Impact Index Per Article: 2.5] [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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10
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Mendonça PRF, Tagliatti E, Langley H, Kotzadimitriou D, Zamora-Chimal CG, Timofeeva Y, Volynski KE. Asynchronous glutamate release is enhanced in low release efficacy synapses and dispersed across the active zone. Nat Commun 2022; 13:3497. [PMID: 35715404 PMCID: PMC9206079 DOI: 10.1038/s41467-022-31070-4] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2021] [Accepted: 05/31/2022] [Indexed: 11/09/2022] Open
Abstract
The balance between fast synchronous and delayed asynchronous release of neurotransmitters has a major role in defining computational properties of neuronal synapses and regulation of neuronal network activity. However, how it is tuned at the single synapse level remains poorly understood. Here, using the fluorescent glutamate sensor SF-iGluSnFR, we image quantal vesicular release in tens to hundreds of individual synaptic outputs from single pyramidal cells with 4 millisecond temporal and 75 nm spatial resolution. We find that the ratio between synchronous and asynchronous synaptic vesicle exocytosis varies extensively among synapses supplied by the same axon, and that the synchronicity of release is reduced at low release probability synapses. We further demonstrate that asynchronous exocytosis sites are more widely distributed within the release area than synchronous sites. Together, our results reveal a universal relationship between the two major functional properties of synapses - the timing and the overall efficacy of neurotransmitter release.
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Affiliation(s)
- Philipe R F Mendonça
- University College London Institute of Neurology, London, UK. .,Department of Physiology and Biophysics, Federal University of Minas Gerais, Gerais, Brazil.
| | - Erica Tagliatti
- University College London Institute of Neurology, London, UK
| | - Helen Langley
- University College London Institute of Neurology, London, UK
| | | | | | - Yulia Timofeeva
- University College London Institute of Neurology, London, UK. .,Department of Computer Science, University of Warwick, Coventry, UK.
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11
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Re-examination of the determinants of synaptic strength from the perspective of superresolution imaging. Curr Opin Neurobiol 2022; 74:102540. [DOI: 10.1016/j.conb.2022.102540] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2021] [Revised: 02/04/2022] [Accepted: 03/03/2022] [Indexed: 11/21/2022]
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12
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An SJ, Stagi M, Gould TJ, Wu Y, Mlodzianoski M, Rivera-Molina F, Toomre D, Strittmatter SM, De Camilli P, Bewersdorf J, Zenisek D. Multimodal imaging of synaptic vesicles with a single probe. CELL REPORTS METHODS 2022; 2:100199. [PMID: 35497490 PMCID: PMC9046237 DOI: 10.1016/j.crmeth.2022.100199] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/26/2021] [Revised: 02/11/2022] [Accepted: 03/28/2022] [Indexed: 05/17/2023]
Abstract
A complete understanding of synaptic-vesicle recycling requires the use of multiple microscopy methods to obtain complementary information. However, many currently available probes are limited to a specific microscopy modality, which necessitates the use of multiple probes and labeling paradigms. Given the complexity of vesicle populations and recycling pathways, having new single-vesicle probes that could be used for multiple microscopy techniques would complement existing sets of tools for studying vesicle function. Here, we present a probe based on the membrane-binding C2 domain of cytosolic phospholipase A2 (cPLA2) that fulfills this need. By conjugating the C2 domain with different detectable tags, we demonstrate that a single, modular probe can allow synaptic vesicles to be imaged at multiple levels of spatial and temporal resolution. Moreover, as a general endocytic marker, the C2 domain may also be used to study membrane recycling in many cell types.
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Affiliation(s)
- Seong J. An
- Department of Cellular and Molecular Physiology, Yale University School of Medicine, New Haven, CT 06510, USA
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT 06510, USA
| | - Massimiliano Stagi
- Program in Cellular Neuroscience, Neurodegeneration & Repair, Yale University School of Medicine, New Haven, CT 06510, USA
- Department of Neurology, Yale University School of Medicine, New Haven, CT 06510, USA
- Kavli Institute of Neuroscience, Yale University School of Medicine, New Haven, CT 06510, USA
- Department of Molecular Physiology & Cell Signalling, Institute of Systems, Molecular & Integrative Biology, University of Liverpool, Liverpool 69 3BX, UK
| | - Travis J. Gould
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT 06510, USA
- Department of Physics and Astronomy, Bates College, Lewiston, ME 04240, USA
| | - Yumei Wu
- Program in Cellular Neuroscience, Neurodegeneration & Repair, Yale University School of Medicine, New Haven, CT 06510, USA
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT 06510, USA
- Howard Hughes Medical Institute, Yale University School of Medicine, New Haven, CT 06510, USA
- Kavli Institute of Neuroscience, Yale University School of Medicine, New Haven, CT 06510, USA
- Department of Neuroscience, Yale University School of Medicine, New Haven, CT 06510, USA
| | - Michael Mlodzianoski
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT 06510, USA
- Department of Biomedical Engineering, Yale University School of Medicine, New Haven, CT 06510, USA
- Kavli Institute of Neuroscience, Yale University School of Medicine, New Haven, CT 06510, USA
| | - Felix Rivera-Molina
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT 06510, USA
| | - Derek Toomre
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT 06510, USA
| | - Stephen M. Strittmatter
- Program in Cellular Neuroscience, Neurodegeneration & Repair, Yale University School of Medicine, New Haven, CT 06510, USA
- Department of Neurology, Yale University School of Medicine, New Haven, CT 06510, USA
- Kavli Institute of Neuroscience, Yale University School of Medicine, New Haven, CT 06510, USA
- Department of Neuroscience, Yale University School of Medicine, New Haven, CT 06510, USA
| | - Pietro De Camilli
- Program in Cellular Neuroscience, Neurodegeneration & Repair, Yale University School of Medicine, New Haven, CT 06510, USA
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT 06510, USA
- Howard Hughes Medical Institute, Yale University School of Medicine, New Haven, CT 06510, USA
- Kavli Institute of Neuroscience, Yale University School of Medicine, New Haven, CT 06510, USA
- Department of Neuroscience, Yale University School of Medicine, New Haven, CT 06510, USA
| | - Joerg Bewersdorf
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT 06510, USA
- Department of Biomedical Engineering, Yale University School of Medicine, New Haven, CT 06510, USA
- Kavli Institute of Neuroscience, Yale University School of Medicine, New Haven, CT 06510, USA
| | - David Zenisek
- Department of Cellular and Molecular Physiology, Yale University School of Medicine, New Haven, CT 06510, USA
- Program in Cellular Neuroscience, Neurodegeneration & Repair, Yale University School of Medicine, New Haven, CT 06510, USA
- Kavli Institute of Neuroscience, Yale University School of Medicine, New Haven, CT 06510, USA
- Department of Neuroscience, Yale University School of Medicine, New Haven, CT 06510, USA
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13
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Matthews EA, Sun W, McMahon SM, Doengi M, Halka L, Anders S, Müller JA, Steinlein P, Vana NS, van Dyk G, Pitsch J, Becker AJ, Pfeifer A, Kavalali ET, Lamprecht A, Henneberger C, Stein V, Schoch S, Dietrich D. Optical analysis of glutamate spread in the neuropil. Cereb Cortex 2022; 32:3669-3689. [PMID: 35059716 PMCID: PMC9433421 DOI: 10.1093/cercor/bhab440] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2021] [Revised: 11/03/2021] [Accepted: 11/09/2021] [Indexed: 11/16/2022] Open
Abstract
Fast synaptic communication uses diffusible transmitters whose spread is limited by uptake mechanisms. However, on the submicron-scale, the distance between two synapses, the extent of glutamate spread has so far remained difficult to measure. Here, we show that quantal glutamate release from individual hippocampal synapses activates extracellular iGluSnFr molecules at a distance of >1.5 μm. 2P-glutamate uncaging near spines further showed that alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA)-Rs and N-methyl-D-aspartate (NMDA)-Rs respond to distant uncaging spots at approximately 800 and 2000 nm, respectively, when releasing the amount of glutamate contained in approximately five synaptic vesicles. The uncaging-induced remote activation of AMPA-Rs was facilitated by blocking glutamate transporters but only modestly decreased by elevating the recording temperature. When mimicking release from neighboring synapses by three simultaneous uncaging spots in the microenvironment of a spine, AMPA-R-mediated responses increased supra-additively. Interfering with extracellular glutamate diffusion through a glutamate scavenger system weakly reduced field synaptic responses but not the quantal amplitude. Together, our data suggest that the neuropil is more permissive to short-range spread of transmitter than suggested by theory, that multivesicular release could regularly coactivate nearest neighbor synapses and that on this scale glutamate buffering by transporters primarily limits the spread of transmitter and allows for cooperative glutamate signaling in extracellular microdomains.
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Affiliation(s)
| | | | | | - M Doengi
- Institute of Physiology, Medical Faculty, University of Bonn, 53115 Bonn, Germany
| | - L Halka
- Institute of Physiology, Medical Faculty, University of Bonn, 53115 Bonn, Germany
| | - S Anders
- Institute of Cellular Neurosciences, Medical Faculty, University of Bonn, 53127 Bonn, Germany
| | - J A Müller
- Section for Translational Epilepsy Research, Department of Neuropathology, University Hospital Bonn, 53127 Bonn, Germany
| | - P Steinlein
- Department of Neurosurgery, University Hospital Bonn, 53127 Bonn, Germany,Department of Pharmaceutics, Institute of Pharmacy, University of Bonn, Bonn, Germany
| | - N S Vana
- Department of Neurosurgery, University Hospital Bonn, 53127 Bonn, Germany
| | - G van Dyk
- Department of Neurosurgery, University Hospital Bonn, 53127 Bonn, Germany
| | - J Pitsch
- Section for Translational Epilepsy Research, Department of Neuropathology, University Hospital Bonn, 53127 Bonn, Germany,Department of Epileptology, University Hospital Bonn, 53127 Bonn, Germany
| | - A J Becker
- Section for Translational Epilepsy Research, Department of Neuropathology, University Hospital Bonn, 53127 Bonn, Germany,Department of Epileptology, University Hospital Bonn, 53127 Bonn, Germany
| | - A Pfeifer
- Institute of Pharmacology and Toxicology, University Hospital, University of Bonn, 53127 Bonn, Germany
| | - E T Kavalali
- Department of Pharmacology, The Vanderbilt Brain Institute, Vanderbilt University, Nashville, TN 37240-7933, USA
| | - A Lamprecht
- Department of Pharmaceutics, Institute of Pharmacy, University of Bonn, Bonn, Germany
| | - C Henneberger
- Institute of Cellular Neurosciences, Medical Faculty, University of Bonn, 53127 Bonn, Germany,German Center for Neurodegenerative Diseases (DZNE), 53127 Bonn, Germany,Institute of Neurology, University College London, London, WC1N 3BG, UK
| | - V Stein
- Institute of Physiology, Medical Faculty, University of Bonn, 53115 Bonn, Germany
| | - S Schoch
- Address correspondence to Prof. Dr Dirk Dietrich, Department of Neurosurgery, University Hospital Bonn, Venusberg Campus 1, Bonn 53127, Germany. ; and Prof. Dr Susanne Schoch, Institute of Neuropathology, University Hospital Bonn, Venusberg Campus 1, Bonn 53127, Germany.
| | - D Dietrich
- Address correspondence to Prof. Dr Dirk Dietrich, Department of Neurosurgery, University Hospital Bonn, Venusberg Campus 1, Bonn 53127, Germany. ; and Prof. Dr Susanne Schoch, Institute of Neuropathology, University Hospital Bonn, Venusberg Campus 1, Bonn 53127, Germany.
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14
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Super-resolution microscopy: a closer look at synaptic dysfunction in Alzheimer disease. Nat Rev Neurosci 2021; 22:723-740. [PMID: 34725519 DOI: 10.1038/s41583-021-00531-y] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/27/2021] [Indexed: 11/08/2022]
Abstract
The synapse has emerged as a critical neuronal structure in the degenerative process of Alzheimer disease (AD), in which the pathogenic signals of two key players - amyloid-β (Aβ) and tau - converge, thereby causing synaptic dysfunction and cognitive deficits. The synapse presents a dynamic, confined microenvironment in which to explore how key molecules travel, localize, interact and assume different levels of organizational complexity, thereby affecting neuronal function. However, owing to their small size and the diffraction-limited resolution of conventional light microscopic approaches, investigating synaptic structure and dynamics has been challenging. Super-resolution microscopy (SRM) techniques have overcome the resolution barrier and are revolutionizing our quantitative understanding of biological systems in unprecedented spatio-temporal detail. Here we review critical new insights provided by SRM into the molecular architecture and dynamic organization of the synapse and, in particular, the interactions between Aβ and tau in this compartment. We further highlight how SRM can transform our understanding of the molecular pathological mechanisms that underlie AD. The application of SRM for understanding the roles of synapses in AD pathology will provide a stepping stone towards a broader understanding of dysfunction in other subcellular compartments and at cellular and circuit levels in this disease.
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15
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Karlocai MR, Heredi J, Benedek T, Holderith N, Lorincz A, Nusser Z. Variability in the Munc13-1 content of excitatory release sites. eLife 2021; 10:67468. [PMID: 33904397 PMCID: PMC8116053 DOI: 10.7554/elife.67468] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2021] [Accepted: 04/26/2021] [Indexed: 01/15/2023] Open
Abstract
The molecular mechanisms underlying the diversity of cortical glutamatergic synapses are still incompletely understood. Here, we tested the hypothesis that presynaptic active zones (AZs) are constructed from molecularly uniform, independent release sites (RSs), the number of which scales linearly with the AZ size. Paired recordings between hippocampal CA1 pyramidal cells and fast-spiking interneurons in acute slices from adult mice followed by quantal analysis demonstrate large variability in the number of RSs (N) at these connections. High-resolution molecular analysis of functionally characterized synapses reveals variability in the content of one of the key vesicle priming factors – Munc13-1 – in AZs that possess the same N. Replica immunolabeling also shows a threefold variability in the total Munc13-1 content of AZs of identical size and a fourfold variability in the size and density of Munc13-1 clusters within the AZs. Our results provide evidence for quantitative molecular heterogeneity of RSs and support a model in which the AZ is built up from variable numbers of molecularly heterogeneous, but independent RSs.
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Affiliation(s)
- Maria Rita Karlocai
- Laboratory of Cellular Neurophysiology, Institute of Experimental Medicine, Budapest, Hungary
| | - Judit Heredi
- Laboratory of Cellular Neurophysiology, Institute of Experimental Medicine, Budapest, Hungary
| | - Tünde Benedek
- Laboratory of Cellular Neurophysiology, Institute of Experimental Medicine, Budapest, Hungary
| | - Noemi Holderith
- Laboratory of Cellular Neurophysiology, Institute of Experimental Medicine, Budapest, Hungary
| | - Andrea Lorincz
- Laboratory of Cellular Neurophysiology, Institute of Experimental Medicine, Budapest, Hungary
| | - Zoltan Nusser
- Laboratory of Cellular Neurophysiology, Institute of Experimental Medicine, Budapest, Hungary
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16
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Maschi D, Gramlich MW, Klyachko VA. Myosin V Regulates Spatial Localization of Different Forms of Neurotransmitter Release in Central Synapses. Front Synaptic Neurosci 2021; 13:650334. [PMID: 33935678 PMCID: PMC8081987 DOI: 10.3389/fnsyn.2021.650334] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2021] [Accepted: 03/03/2021] [Indexed: 11/18/2022] Open
Abstract
Synaptic active zone (AZ) contains multiple specialized release sites for vesicle fusion. The utilization of release sites is regulated to determine spatiotemporal organization of the two main forms of synchronous release, uni-vesicular (UVR) and multi-vesicular (MVR). We previously found that the vesicle-associated molecular motor myosin V regulates temporal utilization of release sites by controlling vesicle anchoring at release sites in an activity-dependent manner. Here we show that acute inhibition of myosin V shifts preferential location of vesicle docking away from AZ center toward periphery, and results in a corresponding spatial shift in utilization of release sites during UVR. Similarly, inhibition of myosin V also reduces preferential utilization of central release sites during MVR, leading to more spatially distributed and temporally uniform MVR that occurs farther away from the AZ center. Using a modeling approach, we provide a conceptual framework that unites spatial and temporal functions of myosin V in vesicle release by controlling the gradient of release site release probability across the AZ, which in turn determines the spatiotemporal organization of both UVR and MVR. Thus myosin V regulates both temporal and spatial utilization of release sites during two main forms of synchronous release.
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Affiliation(s)
- Dario Maschi
- Department of Cell Biology and Physiology, Washington University School of Medicine, St. Louis, MO, United States
| | | | - Vitaly A Klyachko
- Department of Cell Biology and Physiology, Washington University School of Medicine, St. Louis, MO, United States
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17
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Feldmeyer D, Wesseling JF, Sjöström PJ. Editorial: Methods for Synaptic Interrogation. Front Synaptic Neurosci 2020; 12:23. [PMID: 32587510 PMCID: PMC7298142 DOI: 10.3389/fnsyn.2020.00023] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2020] [Accepted: 05/12/2020] [Indexed: 11/23/2022] Open
Affiliation(s)
- Dirk Feldmeyer
- Institute of Neuroscience and Medicine 10 (INM-10), Research Centre Jülich, Jülich, Germany.,Department of Psychiatry, Psychotherapy and Psychosomatics, Medical School, RWTH Aachen University Hospital, Aachen, Germany
| | - John F Wesseling
- Instituto de Neurociencias, CSIC-UMH, San Juan de Alicante, Spain
| | - 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, Canada
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