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Nowacka A, Getz AM, Bessa-Neto D, Choquet D. Activity-dependent diffusion trapping of AMPA receptors as a key step for expression of early LTP. Philos Trans R Soc Lond B Biol Sci 2024; 379:20230220. [PMID: 38853553 DOI: 10.1098/rstb.2023.0220] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2024] [Accepted: 04/11/2024] [Indexed: 06/11/2024] Open
Abstract
This review focuses on the activity-dependent diffusion trapping of α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptors (AMPARs) as a crucial mechanism for the expression of early long-term potentiation (LTP), a process central to learning and memory. Despite decades of research, the precise mechanisms by which LTP induction leads to an increase in AMPAR responses at synapses have been elusive. We review the different hypotheses that have been put forward to explain the increased AMPAR responsiveness during LTP. We discuss the dynamic nature of AMPAR complexes, including their constant turnover and activity-dependent modifications that affect their synaptic accumulation. We highlight a hypothesis suggesting that AMPARs are diffusively trapped at synapses through activity-dependent interactions with protein-based binding slots in the post-synaptic density (PSD), offering a potential explanation for the increased synaptic strength during LTP. Furthermore, we outline the challenges still to be addressed before we fully understand the functional roles and molecular mechanisms of AMPAR dynamic nanoscale organization in LTP. This article is part of a discussion meeting issue 'Long-term potentiation: 50 years on'.
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Affiliation(s)
- Agata Nowacka
- University of Bordeaux, CNRS, Interdisciplinary Institute for Neuroscience, IINS, UMR 5297 , Bordeaux F-33000, France
| | - Angela M Getz
- University of Bordeaux, CNRS, Interdisciplinary Institute for Neuroscience, IINS, UMR 5297 , Bordeaux F-33000, France
- University of Bordeaux, CNRS, INSERM, Bordeaux Imaging Center, BIC, UMS 3420, US 4 , Bordeaux F-33000, France
| | - Diogo Bessa-Neto
- University of Bordeaux, CNRS, Interdisciplinary Institute for Neuroscience, IINS, UMR 5297 , Bordeaux F-33000, France
| | - Daniel Choquet
- University of Bordeaux, CNRS, Interdisciplinary Institute for Neuroscience, IINS, UMR 5297 , Bordeaux F-33000, France
- University of Bordeaux, CNRS, INSERM, Bordeaux Imaging Center, BIC, UMS 3420, US 4 , Bordeaux F-33000, France
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Manning A, Bender PTR, Boyd-Pratt H, Mendelson BZ, Hruska M, Anderson CT. Trans-synaptic Association of Vesicular Zinc Transporter 3 and Shank3 Supports Synapse-Specific Dendritic Spine Structure and Function in the Mouse Auditory Cortex. J Neurosci 2024; 44:e0619242024. [PMID: 38830758 PMCID: PMC11236586 DOI: 10.1523/jneurosci.0619-24.2024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2024] [Revised: 05/17/2024] [Accepted: 05/23/2024] [Indexed: 06/05/2024] Open
Abstract
Shank3 is a synaptic scaffolding protein that assists in tethering and organizing structural proteins and glutamatergic receptors in the postsynaptic density of excitatory synapses. The localization of Shank3 at excitatory synapses and the formation of stable Shank3 complexes is regulated by the binding of zinc to the C-terminal sterile-alpha-motif (SAM) domain of Shank3. Mutations in the SAM domain of Shank3 result in altered synaptic function and morphology, and disruption of zinc in synapses that express Shank3 leads to a reduction of postsynaptic proteins important for synaptic structure and function. This suggests that zinc supports the localization of postsynaptic proteins via Shank3. Many regions of the brain are highly enriched with free zinc inside glutamatergic vesicles at presynaptic terminals. At these synapses, zinc transporter 3 (ZnT3) moves zinc into vesicles where it is co-released with glutamate. Alterations in ZnT3 are implicated in multiple neurodevelopmental disorders, and ZnT3 knock-out (KO) mice-which lack synaptic zinc-show behavioral deficits associated with autism spectrum disorder and schizophrenia. Here we show that male and female ZnT3 KO mice have smaller dendritic spines and miniature excitatory postsynaptic current amplitudes than wildtype (WT) mice in the auditory cortex. Additionally, spine size deficits in ZnT3 KO mice are restricted to synapses that express Shank3. In WT mice, synapses that express both Shank3 and ZnT3 have larger spines compared to synapses that express Shank3 but not ZnT3. Together these findings suggest a mechanism whereby presynaptic ZnT3-dependent zinc supports postsynaptic structure and function via Shank3 in a synapse-specific manner.
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Affiliation(s)
- Abbey Manning
- Department of Neuroscience, West Virginia University School of Medicine, Morgantown, WV 26506
- Rockefeller Neuroscience Institute, West Virginia University School of Medicine, Morgantown, WV 26506
| | - Philip T R Bender
- Department of Neuroscience, West Virginia University School of Medicine, Morgantown, WV 26506
- Rockefeller Neuroscience Institute, West Virginia University School of Medicine, Morgantown, WV 26506
| | - Helen Boyd-Pratt
- Department of Neuroscience, West Virginia University School of Medicine, Morgantown, WV 26506
- Rockefeller Neuroscience Institute, West Virginia University School of Medicine, Morgantown, WV 26506
- Clinical and Translational Science Institute, West Virginia University School of Medicine, Morgantown, WV 26506
| | - Benjamin Z Mendelson
- Department of Neuroscience, West Virginia University School of Medicine, Morgantown, WV 26506
- Rockefeller Neuroscience Institute, West Virginia University School of Medicine, Morgantown, WV 26506
| | - Martin Hruska
- Department of Neuroscience, West Virginia University School of Medicine, Morgantown, WV 26506
- Rockefeller Neuroscience Institute, West Virginia University School of Medicine, Morgantown, WV 26506
| | - Charles T Anderson
- Department of Neuroscience, West Virginia University School of Medicine, Morgantown, WV 26506
- Rockefeller Neuroscience Institute, West Virginia University School of Medicine, Morgantown, WV 26506
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Gupta S, Tielemans A, Guevara CA, Huntley GW, Benson DL. Parkinson's-linked LRRK2-G2019S derails AMPAR trafficking, mobility, and composition in striatum with cell-type and subunit specificity. Proc Natl Acad Sci U S A 2024; 121:e2317833121. [PMID: 38968112 DOI: 10.1073/pnas.2317833121] [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: 10/22/2023] [Accepted: 05/27/2024] [Indexed: 07/07/2024] Open
Abstract
Parkinson's disease (PD) is a multifactorial disease that affects multiple brain systems and circuits. While defined by motor symptoms caused by degeneration of brainstem dopamine neurons, debilitating non-motor abnormalities in fronto-striatal-based cognitive function are common, appear early, and are initially independent of dopamine. Young adult mice expressing the PD-associated G2019S missense mutation in Lrrk2 also exhibit deficits in fronto-striatal-based cognitive tasks. In mice and humans, cognitive functions require dynamic adjustments in glutamatergic synapse strength through cell-surface trafficking of α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid-type glutamate receptors (AMPARs), but it is unknown how LRRK2 mutation impacts dynamic features of AMPAR trafficking in striatal projection neurons (SPNs). Here, we used Lrrk2G2019S knockin mice to show that surface AMPAR subunit stoichiometry is altered biochemically and functionally in mutant SPNs in dorsomedial striatum to favor the incorporation of GluA1 over GluA2. GluA1-containing AMPARs were resistant to internalization from the cell surface, leaving an excessive accumulation of GluA1 on the surface within and outside synapses. This negatively impacted trafficking dynamics that normally support synapse strengthening, as GluA1-containing AMPARs failed to increase at synapses in response to a potentiating stimulus and showed significantly reduced surface mobility. Surface GluA2-containing AMPARs were expressed at normal levels in synapses, indicating subunit-selective impairment. Abnormal surface accumulation of GluA1 was independent of PKA activity and was limited to D1R SPNs. Since LRRK2 mutation is thought to be part of a common PD pathogenic pathway, our data suggest that sustained, striatal cell-type specific changes in AMPAR composition and trafficking contribute to cognitive or other impairments associated with PD.
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Affiliation(s)
- Swati Gupta
- Nash Family Department of Neuroscience, Icahn School of Medicine at Mount Sinai, New York, NY 10029
- Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029
| | - Alexander Tielemans
- Nash Family Department of Neuroscience, Icahn School of Medicine at Mount Sinai, New York, NY 10029
- Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029
- Graduate School of Biomedical Sciences, Icahn School of Medicine at Mount Sinai, New York, NY 10029
| | - Christopher A Guevara
- Nash Family Department of Neuroscience, Icahn School of Medicine at Mount Sinai, New York, NY 10029
- Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029
- Graduate School of Biomedical Sciences, Icahn School of Medicine at Mount Sinai, New York, NY 10029
| | - George W Huntley
- Nash Family Department of Neuroscience, Icahn School of Medicine at Mount Sinai, New York, NY 10029
- Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029
- Graduate School of Biomedical Sciences, Icahn School of Medicine at Mount Sinai, New York, NY 10029
| | - Deanna L Benson
- Nash Family Department of Neuroscience, Icahn School of Medicine at Mount Sinai, New York, NY 10029
- Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029
- Graduate School of Biomedical Sciences, Icahn School of Medicine at Mount Sinai, New York, NY 10029
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4
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Cloâtre T, Mondin M, Sibarita JB, Levet F, Thoumine O. Protocol for matching protein localization to synapse morphology in primary rat neurons by correlative super-resolution microscopy. STAR Protoc 2024; 5:103160. [PMID: 38943646 DOI: 10.1016/j.xpro.2024.103160] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2023] [Revised: 04/17/2024] [Accepted: 06/07/2024] [Indexed: 07/01/2024] Open
Abstract
Super-resolution imaging provides unprecedented visualization of sub-cellular structures, but the two main techniques used, single-molecule localization microscopy (SMLM) and stimulated emission depletion (STED), are not easily reconciled. We present a protocol to super-impose nanoscale protein distribution reconstructed with SMLM to sub-cellular morphology obtained in STED. We describe steps for tracking cells on etched coverslips and registering images from two different microscopes with 30-nm accuracy. In this protocol, synaptic proteins are mapped in the dendritic spines of primary neurons. For complete details on the use and execution of this protocol, please refer to Inavalli et al.1.
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Affiliation(s)
- Tiffany Cloâtre
- University Bordeaux, CNRS, Interdisciplinary Institute for Neuroscience, IINS, UMR 5297, 33000 Bordeaux, France
| | - Magali Mondin
- University Bordeaux, CNRS, INSERM, Bordeaux Imaging Center, BIC, UAR 3420, US 4, 33000 Bordeaux, France
| | - Jean-Baptiste Sibarita
- University Bordeaux, CNRS, Interdisciplinary Institute for Neuroscience, IINS, UMR 5297, 33000 Bordeaux, France
| | - Florian Levet
- University Bordeaux, CNRS, Interdisciplinary Institute for Neuroscience, IINS, UMR 5297, 33000 Bordeaux, France; University Bordeaux, CNRS, INSERM, Bordeaux Imaging Center, BIC, UAR 3420, US 4, 33000 Bordeaux, France.
| | - Olivier Thoumine
- University Bordeaux, CNRS, Interdisciplinary Institute for Neuroscience, IINS, UMR 5297, 33000 Bordeaux, France.
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Fukata Y, Fukata M, MacGillavry HD, Nair D, Hosy E. Celebrating the Birthday of AMPA Receptor Nanodomains: Illuminating the Nanoscale Organization of Excitatory Synapses with 10 Nanocandles. J Neurosci 2024; 44:e2104232024. [PMID: 38839340 PMCID: PMC11154862 DOI: 10.1523/jneurosci.2104-23.2024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2023] [Revised: 04/02/2024] [Accepted: 04/03/2024] [Indexed: 06/07/2024] Open
Abstract
A decade ago, in 2013, and over the course of 4 summer months, three separate observations were reported that each shed light independently on a new molecular organization that fundamentally reshaped our perception of excitatory synaptic transmission (Fukata et al., 2013; MacGillavry et al., 2013; Nair et al., 2013). This discovery unveiled an intricate arrangement of AMPA-type glutamate receptors and their principal scaffolding protein PSD-95, at synapses. This breakthrough was made possible, thanks to advanced super-resolution imaging techniques. It fundamentally changed our understanding of excitatory synaptic architecture and paved the way for a brand-new area of research. In this Progressions article, the primary investigators of the nanoscale organization of synapses have come together to chronicle the tale of their discovery. We recount the initial inquiry that prompted our research, the preceding studies that inspired our work, the technical obstacles that were encountered, and the breakthroughs that were made in the subsequent decade in the realm of nanoscale synaptic transmission. We review the new discoveries made possible by the democratization of super-resolution imaging techniques in the field of excitatory synaptic physiology and architecture, first by the extension to other glutamate receptors and to presynaptic proteins and then by the notion of trans-synaptic organization. After describing the organizational modifications occurring in various pathologies, we discuss briefly the latest technical developments made possible by super-resolution imaging and emerging concepts in synaptic physiology.
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Affiliation(s)
- Yuko Fukata
- Division of Molecular and Cellular Pharmacology, Nagoya University Graduate School of Medicine, Nagoya, Aichi 466-8550, Japan
- Division of Membrane Physiology, Department of Molecular and Cellular Physiology, National Institute for Physiological Sciences, National Institutes of Natural Sciences, Okazaki, Aichi 444-8787, Japan
| | - Masaki Fukata
- Division of Membrane Physiology, Department of Molecular and Cellular Physiology, National Institute for Physiological Sciences, National Institutes of Natural Sciences, Okazaki, Aichi 444-8787, Japan
- Division of Neuropharmacology, Nagoya University Graduate School of Medicine, Nagoya, Aichi 466-8550, Japan
- Department of Physiological Sciences, School of Life Science, SOKENDAI (The Graduate University for Advanced Studies), Okazaki, Aichi 444-8585, Japan
| | - Harold D MacGillavry
- Division of Cell Biology, Neurobiology and Biophysics, Department of Biology, Faculty of Science, Utrecht University, Utrecht 3584 CH, The Netherlands
| | - Deepak Nair
- Centre for Neuroscience, Indian Institute of Science, Bangalore 560012, Karnataka, India
| | - Eric Hosy
- Interdisciplinary Institute for Neuroscience, University of Bordeaux, CNRS UMR5297, Bordeaux F-33000, France
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Chen JH, Tang AH. Nanoscale Reorganization of Glutamate Receptors Underlies Synaptic Plasticity and Pathology. Neurosci Bull 2024; 40:840-844. [PMID: 38372930 PMCID: PMC11178730 DOI: 10.1007/s12264-024-01180-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2023] [Accepted: 11/25/2023] [Indexed: 02/20/2024] Open
Affiliation(s)
- Jia-Hui Chen
- Hefei National Laboratory for Physical Sciences at the Microscale, CAS Key Laboratory of Brain Function and Disease, Neurodegenerative Disorder Research Center and Biomedical Sciences and Health Laboratory of Anhui Province, University of Science and Technology of China, Hefei, 230027, China.
- Institute of Artificial Intelligence, Hefei Comprehensive National Science Center, Hefei, 230088, China.
| | - Ai-Hui Tang
- Hefei National Laboratory for Physical Sciences at the Microscale, CAS Key Laboratory of Brain Function and Disease, Neurodegenerative Disorder Research Center and Biomedical Sciences and Health Laboratory of Anhui Province, University of Science and Technology of China, Hefei, 230027, China.
- Institute of Artificial Intelligence, Hefei Comprehensive National Science Center, Hefei, 230088, China.
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Barti B, Dudok B, Kenesei K, Zöldi M, Miczán V, Balla GY, Zala D, Tasso M, Sagheddu C, Kisfali M, Tóth B, Ledri M, Vizi ES, Melis M, Barna L, Lenkei Z, Soltész I, Katona I. Presynaptic nanoscale components of retrograde synaptic signaling. SCIENCE ADVANCES 2024; 10:eado0077. [PMID: 38809980 PMCID: PMC11135421 DOI: 10.1126/sciadv.ado0077] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/11/2024] [Accepted: 04/23/2024] [Indexed: 05/31/2024]
Abstract
While our understanding of the nanoscale architecture of anterograde synaptic transmission is rapidly expanding, the qualitative and quantitative molecular principles underlying distinct mechanisms of retrograde synaptic communication remain elusive. We show that a particular form of tonic cannabinoid signaling is essential for setting target cell-dependent synaptic variability. It does not require the activity of the two major endocannabinoid-producing enzymes. Instead, by developing a workflow for physiological, anatomical, and molecular measurements at the same unitary synapse, we demonstrate that the nanoscale stoichiometric ratio of type 1 cannabinoid receptors (CB1Rs) to the release machinery is sufficient to predict synapse-specific release probability. Accordingly, selective decrease of extrasynaptic CB1Rs does not affect synaptic transmission, whereas in vivo exposure to the phytocannabinoid Δ9-tetrahydrocannabinol disrupts the intrasynaptic nanoscale stoichiometry and reduces synaptic variability. These findings imply that synapses leverage the nanoscale stoichiometry of presynaptic receptor coupling to the release machinery to establish synaptic strength in a target cell-dependent manner.
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Affiliation(s)
- Benjámin Barti
- Department of Psychological and Brain Sciences, Indiana University Bloomington, 702 N Walnut Grove Ave, Bloomington, IN 47405-2204, USA
- Molecular Neurobiology Research Group, HUN-REN Institute of Experimental Medicine, Szigony st 43, H-1083 Budapest, Hungary
- School of Ph.D. Studies, Semmelweis University, Üllői st 26, H-1085 Budapest, Hungary
| | - Barna Dudok
- Molecular Neurobiology Research Group, HUN-REN Institute of Experimental Medicine, Szigony st 43, H-1083 Budapest, Hungary
- Departments of Neurology and Neuroscience, Baylor College of Medicine, 1 Baylor Plz, Houston, TX 77030, USA
- Department of Neurosurgery, Stanford University, 450 Jane Stanford Way, Stanford, CA 94305, USA
| | - Kata Kenesei
- Molecular Neurobiology Research Group, HUN-REN Institute of Experimental Medicine, Szigony st 43, H-1083 Budapest, Hungary
| | - Miklós Zöldi
- Department of Psychological and Brain Sciences, Indiana University Bloomington, 702 N Walnut Grove Ave, Bloomington, IN 47405-2204, USA
- Molecular Neurobiology Research Group, HUN-REN Institute of Experimental Medicine, Szigony st 43, H-1083 Budapest, Hungary
- School of Ph.D. Studies, Semmelweis University, Üllői st 26, H-1085 Budapest, Hungary
| | - Vivien Miczán
- Molecular Neurobiology Research Group, HUN-REN Institute of Experimental Medicine, Szigony st 43, H-1083 Budapest, Hungary
- Synthetic and Systems Biology Unit, HUN-REN Biological Research Center, Temesvári krt. 62, H-6726 Szeged, Hungary
| | - Gyula Y. Balla
- Molecular Neurobiology Research Group, HUN-REN Institute of Experimental Medicine, Szigony st 43, H-1083 Budapest, Hungary
- School of Ph.D. Studies, Semmelweis University, Üllői st 26, H-1085 Budapest, Hungary
- Translational Behavioral Neuroscience Research Group, HUN-REN Institute of Experimental Medicine, Szigony st 43, H-1083 Budapest, Hungary
| | - Diana Zala
- Université Paris Cité, INSERM, Institute of Psychiatry and Neurosciences of Paris, F-75014 Paris, France
| | - Mariana Tasso
- Institute of Nanosystems, School of Bio and Nanotechnologies, National University of San Martín - CONICET, 25 de Mayo Ave., 1021 San Martín, Argentina
| | - Claudia Sagheddu
- Department of Biomedical Sciences, University of Cagliari, Cittadella Universitaria di Monserrato, Monserrato, 09042 Cagliari, Italy
| | - Máté Kisfali
- Molecular Neurobiology Research Group, HUN-REN Institute of Experimental Medicine, Szigony st 43, H-1083 Budapest, Hungary
- BiTrial Ltd., Tállya st 23, H-1121 Budapest, Hungary
| | - Blanka Tóth
- Department of Inorganic and Analytical Chemistry, Budapest University of Technology and Economics, Szt. Gellért square 4, H-1111 Budapest, Hungary
- Department of Molecular Biology, Semmelweis University, Üllői st 26, H-1085 Budapest, Hungary
| | - Marco Ledri
- Molecular Neurobiology Research Group, HUN-REN Institute of Experimental Medicine, Szigony st 43, H-1083 Budapest, Hungary
- Epilepsy Center, Department of Clinical Sciences, Faculty of Medicine, Lund University, Sölvegatan 17, BMC A11, 221 84 Lund, Sweden
| | - E. Sylvester Vizi
- Molecular Pharmacology Research Group, HUN-REN Institute of Experimental Medicine, Szigony st 43, H-1083 Budapest, Hungary
| | - Miriam Melis
- Department of Biomedical Sciences, University of Cagliari, Cittadella Universitaria di Monserrato, Monserrato, 09042 Cagliari, Italy
| | - László Barna
- Department of Psychological and Brain Sciences, Indiana University Bloomington, 702 N Walnut Grove Ave, Bloomington, IN 47405-2204, USA
| | - Zsolt Lenkei
- Université Paris Cité, INSERM, Institute of Psychiatry and Neurosciences of Paris, F-75014 Paris, France
| | - Iván Soltész
- Department of Neurosurgery, Stanford University, 450 Jane Stanford Way, Stanford, CA 94305, USA
| | - István Katona
- Department of Psychological and Brain Sciences, Indiana University Bloomington, 702 N Walnut Grove Ave, Bloomington, IN 47405-2204, USA
- Molecular Neurobiology Research Group, HUN-REN Institute of Experimental Medicine, Szigony st 43, H-1083 Budapest, Hungary
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Szíber Z, Drouet A, Mondin M, Levet F, Thoumine O. Neuroligin-1 dependent phosphotyrosine signaling in excitatory synapse differentiation. Front Mol Neurosci 2024; 17:1359067. [PMID: 38813439 PMCID: PMC11133670 DOI: 10.3389/fnmol.2024.1359067] [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: 12/20/2023] [Accepted: 04/22/2024] [Indexed: 05/31/2024] Open
Abstract
Introduction The synaptic adhesion molecule neuroligin-1 (NLGN1) is involved in the differentiation of excitatory synapses, but the precise underlying molecular mechanisms are still debated. Here, we explored the role of NLGN1 tyrosine phosphorylation in this process, focusing on a subset of receptor tyrosine kinases (RTKs), namely FGFR1 and Trks, that were previously described to phosphorylate NLGN1 at a unique intracellular residue (Y782). Methods We used pharmacological inhibitors and genetic manipulation of those RTKs in dissociated hippocampal neurons, followed by biochemical measurement of NLGN1 phosphorylation and immunocytochemical staining of excitatory synaptic scaffolds. Results This study shows that: (i) the accumulation of PSD-95 at de novo NLGN1 clusters induced by neurexin crosslinking is reduced by FGFR and Trk inhibitors; (ii) the increase in PSD-95 puncta caused by NLGN1 over-expression is impaired by FGFR and Trk inhibitors; (iii) TrkB activation by BDNF increases NLGN1 phosphorylation; and (iv) TrkB knock-down impairs the increase of PSD-95 puncta caused by NLGN1 over-expression, an effect which is not seen with the NLGN1 Y782A mutant. Discussion Together, our data identify TrkB as one of the major RTKs responsible for NLGN1 tyrosine phosphorylation, and reveal that TrkB activity is necessary for the synaptogenic effects of NLGN1.
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Affiliation(s)
- Zsófia Szíber
- University of Bordeaux, CNRS, Interdisciplinary Institute for Neuroscience, IINS, UMR 5297, Bordeaux, France
| | - Adèle Drouet
- University of Bordeaux, CNRS, Interdisciplinary Institute for Neuroscience, IINS, UMR 5297, Bordeaux, France
| | - Magali Mondin
- University of Bordeaux, CNRS, INSERM, Bordeaux Imaging Center, BIC, UAR 3420, US 4, Bordeaux, France
| | - Florian Levet
- University of Bordeaux, CNRS, Interdisciplinary Institute for Neuroscience, IINS, UMR 5297, Bordeaux, France
- University of Bordeaux, CNRS, INSERM, Bordeaux Imaging Center, BIC, UAR 3420, US 4, Bordeaux, France
| | - Olivier Thoumine
- University of Bordeaux, CNRS, Interdisciplinary Institute for Neuroscience, IINS, UMR 5297, Bordeaux, France
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Jones G, Akter Y, Shifflett V, Hruska M. Nanoscale analysis of functionally diverse glutamatergic synapses in the neocortex reveals input and layer-specific organization. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.05.01.592008. [PMID: 38746319 PMCID: PMC11092571 DOI: 10.1101/2024.05.01.592008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2024]
Abstract
Discovery of synaptic nanostructures suggests a molecular logic for the flexibility of synaptic function. We still have little understanding of how functionally diverse synapses in the brain organize their nanoarchitecture due to challenges associated with super-resolution imaging in complex brain tissue. Here, we characterized single-domain camelid nanobodies for the 3D quantitative multiplex imaging of synaptic nano-organization in 6 µm brain cryosections using STED nanoscopy. We focused on thalamocortical (TC) and corticocortical (CC) synapses along the apical-basal axis of layer 5 pyramidal neurons as models of functionally diverse glutamatergic synapses in the brain. Spines receiving TC input were larger than CC spines in all layers examined. However, TC synapses on apical and basal dendrites conformed to different organizational principles. TC afferents on apical dendrites frequently contacted spines with multiple aligned PSD-95/Bassoon nanomodules, which are larger. TC spines on basal dendrites contained mostly one aligned PSD-95/Bassoon nanocluster. However, PSD-95 nanoclusters were larger and scaled with spine volume. The nano-organization of CC synapses did not change across cortical layers. These results highlight striking nanoscale diversity of functionally distinct glutamatergic synapses, relying on afferent input and sub-cellular localization of individual synaptic connections.
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Chen Y, Liu S, Jacobi AA, Jeng G, Ulrich JD, Stein IS, Patriarchi T, Hell JW. Rapid sequential clustering of NMDARs, CaMKII, and AMPARs upon activation of NMDARs at developing synapses. Front Synaptic Neurosci 2024; 16:1291262. [PMID: 38660466 PMCID: PMC11039796 DOI: 10.3389/fnsyn.2024.1291262] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2023] [Accepted: 03/22/2024] [Indexed: 04/26/2024] Open
Abstract
Rapid, synapse-specific neurotransmission requires the precise alignment of presynaptic neurotransmitter release and postsynaptic receptors. How postsynaptic glutamate receptor accumulation is induced during maturation is not well understood. We find that in cultures of dissociated hippocampal neurons at 11 days in vitro (DIV) numerous synaptic contacts already exhibit pronounced accumulations of the pre- and postsynaptic markers synaptotagmin, synaptophysin, synapsin, bassoon, VGluT1, PSD-95, and Shank. The presence of an initial set of AMPARs and NMDARs is indicated by miniature excitatory postsynaptic currents (mEPSCs). However, AMPAR and NMDAR immunostainings reveal rather smooth distributions throughout dendrites and synaptic enrichment is not obvious. We found that brief periods of Ca2+ influx through NMDARs induced a surprisingly rapid accumulation of NMDARs within 1 min, followed by accumulation of CaMKII and then AMPARs within 2-5 min. Postsynaptic clustering of NMDARs and AMPARs was paralleled by an increase in their mEPSC amplitudes. A peptide that blocked the interaction of NMDAR subunits with PSD-95 prevented the NMDAR clustering. NMDAR clustering persisted for 3 days indicating that brief periods of elevated glutamate fosters permanent accumulation of NMDARs at postsynaptic sites in maturing synapses. These data support the model that strong glutamatergic stimulation of immature glutamatergic synapses results in a fast and substantial increase in postsynaptic NMDAR content that required NMDAR binding to PSD-95 or its homologues and is followed by recruitment of CaMKII and subsequently AMPARs.
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Affiliation(s)
- Yucui Chen
- Department of Pharmacology, University of Iowa, Iowa City, IA, United States
| | - Shangming Liu
- Department of Pharmacology, University of California, Davis, Davis, CA, United States
| | - Ariel A. Jacobi
- Department of Pharmacology, University of California, Davis, Davis, CA, United States
| | - Grace Jeng
- Department of Pharmacology, University of California, Davis, Davis, CA, United States
| | - Jason D. Ulrich
- Department of Pharmacology, University of Iowa, Iowa City, IA, United States
| | - Ivar S. Stein
- Department of Pharmacology, University of Iowa, Iowa City, IA, United States
- Department of Pharmacology, University of California, Davis, Davis, CA, United States
| | - Tommaso Patriarchi
- Department of Pharmacology, University of California, Davis, Davis, CA, United States
| | - Johannes W. Hell
- Department of Pharmacology, University of Iowa, Iowa City, IA, United States
- Department of Pharmacology, University of California, Davis, Davis, CA, United States
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11
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Srikanth KD, Elahi H, Chander P, Washburn HR, Hassler S, Mwirigi JM, Kume M, Loucks J, Arjarapu R, Hodge R, Shiers SI, Sankaranarayanan I, Erdjument-Bromage H, Neubert TA, Campbell ZT, Paik R, Price TJ, Dalva MB. VLK drives extracellular phosphorylation of EphB2 to govern the EphB2-NMDAR interaction and injury-induced pain. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.03.18.585314. [PMID: 38562765 PMCID: PMC10983893 DOI: 10.1101/2024.03.18.585314] [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
Phosphorylation of hundreds of protein extracellular domains is mediated by two kinase families, yet the significance of these kinases is underexplored. Here, we find that the presynaptic release of the tyrosine directed-ectokinase, Vertebrate Lonesome Kinase (VLK/Pkdcc), is necessary and sufficient for the direct extracellular interaction between EphB2 and GluN1 at synapses, for phosphorylation of the ectodomain of EphB2, and for injury-induced pain. Pkdcc is an essential gene in the nervous system, and VLK is found in synaptic vesicles, and is released from neurons in a SNARE-dependent fashion. VLK is expressed by nociceptive sensory neurons where presynaptic sensory neuron-specific knockout renders mice impervious to post-surgical pain, without changing proprioception. VLK defines an extracellular mechanism that regulates protein-protein interaction and non-opioid-dependent pain in response to injury.
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Affiliation(s)
- Kolluru D. Srikanth
- Tulane Brain Institute, Department of Cell and Molecular Biology, Tulane University; New Orleans, LA 70118, USA
- Jefferson Synaptic Biology Center, Department of Neuroscience, Thomas Jefferson University, Philadelphia, PA 19107
| | - Hajira Elahi
- Department of Neuroscience, The University of Texas at Dallas; Richardson, TX 75080, USA
- Center for Advanced Pain Studies, University of Texas at Dallas; Richardson, TX 75080, USA
| | - Praveen Chander
- Tulane Brain Institute, Department of Cell and Molecular Biology, Tulane University; New Orleans, LA 70118, USA
- Jefferson Synaptic Biology Center, Department of Neuroscience, Thomas Jefferson University, Philadelphia, PA 19107
| | - Halley R. Washburn
- Jefferson Synaptic Biology Center, Department of Neuroscience, Thomas Jefferson University, Philadelphia, PA 19107
- Department of Molecular Biology, Princeton University; Princeton, NJ 08544, USA
| | - Shayne Hassler
- Department of Neuroscience, The University of Texas at Dallas; Richardson, TX 75080, USA
- College of Medicine, University of Houston; Houston, TX 77004, USA
| | - Juliet M. Mwirigi
- Department of Neuroscience, The University of Texas at Dallas; Richardson, TX 75080, USA
- Center for Advanced Pain Studies, University of Texas at Dallas; Richardson, TX 75080, USA
| | - Moeno Kume
- Department of Neuroscience, The University of Texas at Dallas; Richardson, TX 75080, USA
- Center for Advanced Pain Studies, University of Texas at Dallas; Richardson, TX 75080, USA
| | - Jessica Loucks
- Department of Neuroscience, The University of Texas at Dallas; Richardson, TX 75080, USA
| | - Rohita Arjarapu
- Department of Neuroscience, The University of Texas at Dallas; Richardson, TX 75080, USA
| | - Rachel Hodge
- Jefferson Synaptic Biology Center, Department of Neuroscience, Thomas Jefferson University, Philadelphia, PA 19107
| | - Stephanie I. Shiers
- Department of Neuroscience, The University of Texas at Dallas; Richardson, TX 75080, USA
- Center for Advanced Pain Studies, University of Texas at Dallas; Richardson, TX 75080, USA
| | - Ishwarya Sankaranarayanan
- Department of Neuroscience, The University of Texas at Dallas; Richardson, TX 75080, USA
- Center for Advanced Pain Studies, University of Texas at Dallas; Richardson, TX 75080, USA
| | - Hediye Erdjument-Bromage
- Department of Neuroscience and Physiology and Neuroscience Institute, NYU Grossman School of Medicine, New York, NY, 10016, USA
| | - Thomas A. Neubert
- Department of Neuroscience and Physiology and Neuroscience Institute, NYU Grossman School of Medicine, New York, NY, 10016, USA
| | - Zachary T. Campbell
- Department of Anesthesiology, University of Wisconsin-Madison; Madison, WI 53792, USA
| | - Raehum Paik
- Department of Anesthesiology, University of Wisconsin-Madison; Madison, WI 53792, USA
- Department of Genetics, University of Texas Health Science Center at San Antonio; San Antonio, TX 78229, USA
| | - Theodore J. Price
- Department of Neuroscience, The University of Texas at Dallas; Richardson, TX 75080, USA
- Center for Advanced Pain Studies, University of Texas at Dallas; Richardson, TX 75080, USA
| | - Matthew B. Dalva
- Tulane Brain Institute, Department of Cell and Molecular Biology, Tulane University; New Orleans, LA 70118, USA
- Jefferson Synaptic Biology Center, Department of Neuroscience, Thomas Jefferson University, Philadelphia, PA 19107
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12
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Verma H, Kaur S, Kaur S, Gangwar P, Dhiman M, Mantha AK. Role of Cytoskeletal Elements in Regulation of Synaptic Functions: Implications Toward Alzheimer's Disease and Phytochemicals-Based Interventions. Mol Neurobiol 2024:10.1007/s12035-024-04053-3. [PMID: 38491338 DOI: 10.1007/s12035-024-04053-3] [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: 07/03/2023] [Accepted: 02/13/2024] [Indexed: 03/18/2024]
Abstract
Alzheimer's disease (AD), a multifactorial disease, is characterized by the accumulation of neurofibrillary tangles (NFTs) and amyloid beta (Aβ) plaques. AD is triggered via several factors like alteration in cytoskeletal proteins, a mutation in presenilin 1 (PSEN1), presenilin 2 (PSEN2), amyloid precursor protein (APP), and post-translational modifications (PTMs) in the cytoskeletal elements. Owing to the major structural and functional role of cytoskeletal elements, like the organization of axon initial segmentation, dendritic spines, synaptic regulation, and delivery of cargo at the synapse; modulation of these elements plays an important role in AD pathogenesis; like Tau is a microtubule-associated protein that stabilizes the microtubules, and it also causes inhibition of nucleo-cytoplasmic transportation by disrupting the integrity of nuclear pore complex. One of the major cytoskeletal elements, actin and its dynamics, regulate the dendritic spine structure and functions; impairments have been documented towards learning and memory defects. The second major constituent of these cytoskeletal elements, microtubules, are necessary for the delivery of the cargo, like ion channels and receptors at the synaptic membranes, whereas actin-binding protein, i.e., Cofilin's activation form rod-like structures, is involved in the formation of paired helical filaments (PHFs) observed in AD. Also, the glial cells rely on their cytoskeleton to maintain synaptic functionality. Thus, making cytoskeletal elements and their regulation in synaptic structure and function as an important aspect to be focused for better management and targeting AD pathology. This review advocates exploring phytochemicals and Ayurvedic plant extracts against AD by elucidating their neuroprotective mechanisms involving cytoskeletal modulation and enhancing synaptic plasticity. However, challenges include their limited bioavailability due to the poor solubility and the limited potential to cross the blood-brain barrier (BBB), emphasizing the need for targeted strategies to improve therapeutic efficacy.
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Affiliation(s)
- Harkomal Verma
- Department of Zoology, School of Basic Sciences, Central University of Punjab, Village Ghudda, VPO - Ghudda, Bathinda, 151 401, Punjab, India
| | - Sharanjot Kaur
- Department of Microbiology, School of Basic Sciences, Central University of Punjab, Village Ghudda, Bathinda, Punjab, India
| | - Sukhchain Kaur
- Department of Microbiology, School of Basic Sciences, Central University of Punjab, Village Ghudda, Bathinda, Punjab, India
| | - Prabhakar Gangwar
- Department of Zoology, School of Basic Sciences, Central University of Punjab, Village Ghudda, VPO - Ghudda, Bathinda, 151 401, Punjab, India
| | - Monisha Dhiman
- Department of Microbiology, School of Basic Sciences, Central University of Punjab, Village Ghudda, Bathinda, Punjab, India
| | - Anil Kumar Mantha
- Department of Zoology, School of Basic Sciences, Central University of Punjab, Village Ghudda, VPO - Ghudda, Bathinda, 151 401, Punjab, India.
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13
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Feng Y, Brunel N. Attractor neural networks with double well synapses. PLoS Comput Biol 2024; 20:e1011354. [PMID: 38324630 PMCID: PMC10878535 DOI: 10.1371/journal.pcbi.1011354] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2023] [Revised: 02/20/2024] [Accepted: 01/23/2024] [Indexed: 02/09/2024] Open
Abstract
It is widely believed that memory storage depends on activity-dependent synaptic modifications. Classical studies of learning and memory in neural networks describe synaptic efficacy either as continuous or discrete. However, recent results suggest an intermediate scenario in which synaptic efficacy can be described by a continuous variable, but whose distribution is peaked around a small set of discrete values. Motivated by these results, we explored a model in which each synapse is described by a continuous variable that evolves in a potential with multiple minima. External inputs to the network can switch synapses from one potential well to another. Our analytical and numerical results show that this model can interpolate between models with discrete synapses which correspond to the deep potential limit, and models in which synapses evolve in a single quadratic potential. We find that the storage capacity of the network with double well synapses exhibits a power law dependence on the network size, rather than the logarithmic dependence observed in models with single well synapses. In addition, synapses with deeper potential wells lead to more robust information storage in the presence of noise. When memories are sparsely encoded, the scaling of the capacity with network size is similar to previously studied network models in the sparse coding limit.
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Affiliation(s)
- Yu Feng
- Department of Physics, Duke University, Durham, North Carolina, United States of America
| | - Nicolas Brunel
- Department of Physics, Duke University, Durham, North Carolina, United States of America
- Department of Neurobiology, Duke University, Durham, North Carolina, United States of America
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14
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Clavet-Fournier V, Lee C, Wegner W, Brose N, Rhee J, Willig KI. Pre- and postsynaptic nanostructures increase in size and complexity after induction of long-term potentiation. iScience 2024; 27:108679. [PMID: 38213627 PMCID: PMC10783556 DOI: 10.1016/j.isci.2023.108679] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2023] [Revised: 11/09/2023] [Accepted: 12/05/2023] [Indexed: 01/13/2024] Open
Abstract
Synapses, specialized contact sites between neurons, are the fundamental elements of neuronal information transfer. Synaptic plasticity involves changes in synaptic morphology and the number of neurotransmitter receptors, and is thought to underlie learning and memory. However, it is not clear how these structural and functional changes are connected. We utilized time-lapse super-resolution STED microscopy of organotypic hippocampal brain slices and cultured neurons to visualize structural changes of the synaptic nano-organization of the postsynaptic scaffolding protein PSD95, the presynaptic scaffolding protein Bassoon, and the GluA2 subunit of AMPA receptors by chemically induced long-term potentiation (cLTP) at the level of single synapses. We found that the nano-organization of all three proteins increased in complexity and size after cLTP induction. The increase was largely synchronous, peaking at ∼60 min after stimulation. Therefore, both the size and complexity of individual pre- and post-synaptic nanostructures serve as substrates for tuning and determining synaptic strength.
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Affiliation(s)
- Valérie Clavet-Fournier
- Group of Optical Nanoscopy in Neuroscience, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany
- Göttingen Graduate Center for Neurosciences, Biophysics, und Molecular Biosciences (GGNB), Göttingen, Germany
| | - ChungKu Lee
- Department of Molecular Neurobiology, Synaptic Physiology Group, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany
| | - Waja Wegner
- Group of Optical Nanoscopy in Neuroscience, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany
- Center for Nanoscale Microscopy and Molecular Physiology of the Brain, University Medical Center Göttingen, Göttingen, Germany
| | - Nils Brose
- Department of Molecular Neurobiology, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany
| | - JeongSeop Rhee
- Department of Molecular Neurobiology, Synaptic Physiology Group, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany
| | - Katrin I. Willig
- Group of Optical Nanoscopy in Neuroscience, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany
- Center for Nanoscale Microscopy and Molecular Physiology of the Brain, University Medical Center Göttingen, Göttingen, Germany
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15
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Dharmasri PA, DeMarco EM, Anderson MC, Levy AD, Blanpied TA. Loss of postsynaptic NMDARs drives nanoscale reorganization of Munc13-1 and PSD-95. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.01.12.574705. [PMID: 38260705 PMCID: PMC10802569 DOI: 10.1101/2024.01.12.574705] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/24/2024]
Abstract
Nanoscale protein organization within the active zone (AZ) and post-synaptic density (PSD) influences synaptic transmission. Nanoclusters of presynaptic Munc13-1 are associated with readily releasable pool size and neurotransmitter vesicle priming, while postsynaptic PSD-95 nanoclusters coordinate glutamate receptors across from release sites to control their opening probability. Nanocluster number, size, and protein density vary between synapse types and with development and plasticity, supporting a wide range of functional states at the synapse. Whether or how the receptors themselves control this critical architecture remains unclear. One prominent PSD molecular complex is the NMDA receptor (NMDAR). NMDARs coordinate several modes of signaling within synapses, giving them the potential to influence synaptic organization through direct protein interactions or through signaling. We found that loss of NMDARs results in larger synapses that contain smaller, denser, and more numerous PSD-95 nanoclusters. Intriguingly, NMDAR loss also generates retrograde reorganization of the active zone, resulting in denser, more numerous Munc13-1 nanoclusters, more of which are aligned with PSD-95 nanoclusters. Together, these changes to synaptic nanostructure predict stronger AMPA receptor-mediated transmission in the absence of NMDARs. Notably, while prolonged antagonism of NMDAR activity increases Munc13-1 density within nanoclusters, it does not fully recapitulate these trans-synaptic effects. Thus, our results confirm that NMDARs play an important role in maintaining pre- and postsynaptic nanostructure and suggest that both decreased NMDAR expression and suppressed NMDAR activity may exert distinct effects on synaptic function, yet through unique architectural mechanisms.
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Affiliation(s)
- Poorna A Dharmasri
- Program in Neuroscience, University of Maryland School of Medicine, Baltimore, MD, USA
- Department of Physiology, University of Maryland School of Medicine, Baltimore, MD, USA
- University of Maryland Medicine Institute of Neuroscience Discovery, Baltimore, MD, USA
- Current address: Solomon H. Snyder Department of Neuroscience, Johns Hopkins University, School of Medicine, Baltimore, MD, USA
| | - Emily M DeMarco
- Program in Neuroscience, University of Maryland School of Medicine, Baltimore, MD, USA
- Department of Physiology, University of Maryland School of Medicine, Baltimore, MD, USA
- University of Maryland Medicine Institute of Neuroscience Discovery, Baltimore, MD, USA
| | - Michael C Anderson
- Program in Neuroscience, University of Maryland School of Medicine, Baltimore, MD, USA
- Department of Physiology, University of Maryland School of Medicine, Baltimore, MD, USA
- University of Maryland Medicine Institute of Neuroscience Discovery, Baltimore, MD, USA
| | - Aaron D Levy
- Department of Physiology, University of Maryland School of Medicine, Baltimore, MD, USA
- University of Maryland Medicine Institute of Neuroscience Discovery, Baltimore, MD, USA
| | - Thomas A Blanpied
- Department of Physiology, University of Maryland School of Medicine, Baltimore, MD, USA
- University of Maryland Medicine Institute of Neuroscience Discovery, Baltimore, MD, USA
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16
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Kruzich E, Phadke RA, Brack A, Stroumbakis D, Infante O, Cruz-Martín A. A pipeline for STED super-resolution imaging and Imaris analysis of nanoscale synapse organization in mouse cortical brain slices. STAR Protoc 2023; 4:102707. [PMID: 37948187 PMCID: PMC10658395 DOI: 10.1016/j.xpro.2023.102707] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2023] [Revised: 09/28/2023] [Accepted: 10/22/2023] [Indexed: 11/12/2023] Open
Abstract
Advances in super-resolution imaging enable us to delve into its intricate structural and functional complexities with unprecedented detail. Here, we present a pipeline to visualize and analyze the nanoscale organization of cortical layer 1 apical dendritic spines in the mouse prefrontal cortex. We describe steps for brain slice preparation, immunostaining, stimulated emission depletion super-resolution microscopy, and data analysis using the Imaris software package. This protocol allows the study of physiologically relevant brain circuits implicated in neuropsychiatric disorders.
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Affiliation(s)
- Ezra Kruzich
- Neurobiology Section in the Department of Biology, Boston University, Boston, MA 02215, USA.
| | - Rhushikesh A Phadke
- Molecular Biology, Cell Biology, and Biochemistry Section in the Department of Biology, Boston University, Boston, MA 02215, USA
| | - Alison Brack
- Molecular Biology, Cell Biology, and Biochemistry Section in the Department of Biology, Boston University, Boston, MA 02215, USA
| | - Dimitri Stroumbakis
- Neurobiology Section in the Department of Biology, Boston University, Boston, MA 02215, USA
| | - Oriannys Infante
- Montclair State University, Montclair, NJ 07043, USA; Summer Undergraduate Research Fellowship Program, Boston University, Boston, MA 02215, USA
| | - Alberto Cruz-Martín
- Neurobiology Section in the Department of Biology, Boston University, Boston, MA 02215, USA; Molecular Biology, Cell Biology, and Biochemistry Section in the Department of Biology, Boston University, Boston, MA 02215, USA.
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17
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Olah SS, Kareemo DJ, Buchta WC, Sinnen BL, Miller CN, Actor-Engel HS, Gookin SE, Winborn CS, Kleinjan MS, Crosby KC, Aoto J, Smith KR, Kennedy MJ. Acute reorganization of postsynaptic GABA A receptors reveals the functional impact of molecular nanoarchitecture at inhibitory synapses. Cell Rep 2023; 42:113331. [PMID: 37910506 PMCID: PMC10782565 DOI: 10.1016/j.celrep.2023.113331] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2023] [Revised: 09/01/2023] [Accepted: 10/06/2023] [Indexed: 11/03/2023] Open
Abstract
Neurotransmitter receptors partition into nanometer-scale subdomains within the postsynaptic membrane that are precisely aligned with presynaptic neurotransmitter release sites. While spatial coordination between pre- and postsynaptic elements is observed at both excitatory and inhibitory synapses, the functional significance of this molecular architecture has been challenging to evaluate experimentally. Here we utilized an optogenetic clustering approach to acutely alter the nanoscale organization of the postsynaptic inhibitory scaffold gephyrin while monitoring synaptic function. Gephyrin clustering rapidly enlarged postsynaptic area, laterally displacing GABAA receptors from their normally precise apposition with presynaptic active zones. Receptor displacement was accompanied by decreased synaptic GABAA receptor currents even though presynaptic release probability and the overall abundance and function of synaptic GABAA receptors remained unperturbed. Thus, acutely repositioning neurotransmitter receptors within the postsynaptic membrane profoundly influences synaptic efficacy, establishing the functional importance of precision pre-/postsynaptic molecular coordination at inhibitory synapses.
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Affiliation(s)
- Samantha S Olah
- Department of Pharmacology, University of Colorado School of Medicine, Aurora, CO 80045, USA
| | - Dean J Kareemo
- Department of Pharmacology, University of Colorado School of Medicine, Aurora, CO 80045, USA
| | - William C Buchta
- Department of Pharmacology, University of Colorado School of Medicine, Aurora, CO 80045, USA
| | - Brooke L Sinnen
- Department of Pharmacology, University of Colorado School of Medicine, Aurora, CO 80045, USA
| | - Carley N Miller
- Department of Pharmacology, University of Colorado School of Medicine, Aurora, CO 80045, USA
| | - Hannah S Actor-Engel
- Department of Pharmacology, University of Colorado School of Medicine, Aurora, CO 80045, USA
| | - Sara E Gookin
- Department of Pharmacology, University of Colorado School of Medicine, Aurora, CO 80045, USA
| | - Christina S Winborn
- Department of Pharmacology, University of Colorado School of Medicine, Aurora, CO 80045, USA
| | - Mason S Kleinjan
- Department of Pharmacology, University of Colorado School of Medicine, Aurora, CO 80045, USA
| | - Kevin C Crosby
- Department of Pharmacology, University of Colorado School of Medicine, Aurora, CO 80045, USA
| | - Jason Aoto
- Department of Pharmacology, University of Colorado School of Medicine, Aurora, CO 80045, USA
| | - Katharine R Smith
- Department of Pharmacology, University of Colorado School of Medicine, Aurora, CO 80045, USA
| | - Matthew J Kennedy
- Department of Pharmacology, University of Colorado School of Medicine, Aurora, CO 80045, USA.
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18
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Gupta S, Guevara CA, Tielemans A, Huntley GW, Benson DL. Parkinson's-linked LRRK2-G2019S derails AMPAR trafficking, mobility and composition in striatum with cell-type and subunit specificity. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.10.13.562231. [PMID: 37905106 PMCID: PMC10614818 DOI: 10.1101/2023.10.13.562231] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/02/2023]
Abstract
Parkinson's (PD) is a multi-factorial disease that affects multiple brain systems and circuits. While defined by motor symptoms caused by degeneration of brainstem dopamine neurons, debilitating non-motor abnormalities in fronto-striatal based cognitive function are common, appear early and are initially independent of dopamine. Young adult mice expressing the PD-associated G2019S missense mutation in Lrrk2 also exhibit deficits in fronto-striatal-based cognitive tasks. In mice and humans, cognitive functions require dynamic adjustments in glutamatergic synapse strength through cell-surface trafficking of AMPA-type glutamate receptors (AMPARs), but it is unknown how LRRK2 mutation impacts dynamic features of AMPAR trafficking in striatal projection neurons (SPNs). Here, we used Lrrk2 G2019S knockin mice to show that surface AMPAR subunit stoichiometry is altered biochemically and functionally in mutant SPNs to favor incorporation of GluA1 over GluA2. GluA1-containing AMPARs were resistant to internalization from the cell surface, leaving an excessive accumulation of GluA1 on the surface within and outside synapses. This negatively impacted trafficking dynamics that normally support synapse strengthening, as GluA1-containing AMPARs failed to increase at synapses in response to a potentiating stimulus and showed significantly reduced surface mobility. Surface GluA2-containing AMPARs were expressed at normal levels in synapses, indicating subunit-selective impairment. Abnormal surface accumulation of GluA1 was independent of PKA activity and was limited to D 1 R SPNs. Since LRRK2 mutation is thought to be part of a common PD pathogenic pathway, our data suggest that sustained, striatal cell-type specific changes in AMPAR composition and trafficking contribute to cognitive or other impairments associated with PD. SIGNIFICANCE STATEMENT Mutations in LRRK2 are common genetic risks for PD. Lrrk2 G2019S mice fail to exhibit long-term potentiation at corticostriatal synapses and show significant deficits in frontal-striatal based cognitive tasks. While LRRK2 has been implicated generally in protein trafficking, whether G2019S derails AMPAR trafficking at synapses on striatal neurons (SPNs) is unknown. We show that surface GluA1-AMPARs fail to internalize and instead accumulate excessively within and outside synapses. This effect is selective to D 1 R SPNs and negatively impacts synapse strengthening as GluA1-AMPARs fail to increase at the surface in response to potentiation and show limited surface mobility. Thus, LRRK2-G2019S narrows the effective range of plasticity mechanisms, supporting the idea that cognitive symptoms reflect an imbalance in AMPAR trafficking mechanisms within cell-type specific projections.
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19
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Gardeazabal Rodriguez PF, Lilach Y, Ambegaonkar A, Vitali T, Jafri H, Sohn HW, Dalva M, Pierce S, Chung I. MAxSIM: multi-angle-crossing structured illumination microscopy with height-controlled mirror for 3D topological mapping of live cells. Commun Biol 2023; 6:1034. [PMID: 37828050 PMCID: PMC10570291 DOI: 10.1038/s42003-023-05380-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2023] [Accepted: 09/21/2023] [Indexed: 10/14/2023] Open
Abstract
Mapping 3D plasma membrane topology in live cells can bring unprecedented insights into cell biology. Widefield-based super-resolution methods such as 3D-structured illumination microscopy (3D-SIM) can achieve twice the axial ( ~ 300 nm) and lateral ( ~ 100 nm) resolution of widefield microscopy in real time in live cells. However, twice-resolution enhancement cannot sufficiently visualize nanoscale fine structures of the plasma membrane. Axial interferometry methods including fluorescence light interference contrast microscopy and its derivatives (e.g., scanning angle interference microscopy) can determine nanoscale axial locations of proteins on and near the plasma membrane. Thus, by combining super-resolution lateral imaging of 2D-SIM with axial interferometry, we developed multi-angle-crossing structured illumination microscopy (MAxSIM) to generate multiple incident angles by fast, optoelectronic creation of diffraction patterns. Axial localization accuracy can be enhanced by placing cells on a bottom glass substrate, locating a custom height-controlled mirror (HCM) at a fixed axial position above the glass substrate, and optimizing the height reconstruction algorithm for noisy experimental data. The HCM also enables imaging of both the apical and basal surfaces of a cell. MAxSIM with HCM offers high-fidelity nanoscale 3D topological mapping of cell plasma membranes with near-real-time ( ~ 0.5 Hz) imaging of live cells and 3D single-molecule tracking.
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Affiliation(s)
| | - Yigal Lilach
- Nanofabrication and Imaging Center, George Washington University, Washington, DC, USA
| | - Abhijit Ambegaonkar
- Laboratory of Immunogenetics, National Institute of Allergy and Infectious Disease, National Institutes of Health, Rockville, MD, USA
| | - Teresa Vitali
- Department of Anatomy and Cell Biology, George Washington University, School of Medicine and Health Sciences, Washington, DC, USA
| | - Haani Jafri
- Department of Neuroscience, Thomas Jefferson University, Philadelphia, PA, USA
| | - Hae Won Sohn
- Laboratory of Immunogenetics, National Institute of Allergy and Infectious Disease, National Institutes of Health, Rockville, MD, USA
| | - Matthew Dalva
- Department of Neuroscience, Thomas Jefferson University, Philadelphia, PA, USA
- Department of Cell and Molecular Biology, Tulane University, New Orleans, LA, USA
| | - Susan Pierce
- Laboratory of Immunogenetics, National Institute of Allergy and Infectious Disease, National Institutes of Health, Rockville, MD, USA
| | - Inhee Chung
- Department of Anatomy and Cell Biology, George Washington University, School of Medicine and Health Sciences, Washington, DC, USA.
- Department of Biomedical Engineering, GW School of Engineering and Applied Science, George Washington University, Washington, DC, USA.
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20
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Srivastav S, Cui X, Varela RB, Kesby JP, Eyles D. Increasing dopamine synthesis in nigrostriatal circuits increases phasic dopamine release and alters dorsal striatal connectivity: implications for schizophrenia. SCHIZOPHRENIA (HEIDELBERG, GERMANY) 2023; 9:69. [PMID: 37798312 PMCID: PMC10556015 DOI: 10.1038/s41537-023-00397-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/06/2023] [Accepted: 09/18/2023] [Indexed: 10/07/2023]
Abstract
One of the most robust neurochemical abnormalities reported in patients with schizophrenia is an increase in dopamine (DA) synthesis and release, restricted to the dorsal striatum (DS). This hyper functionality is strongly associated with psychotic symptoms and progresses in those who later transition to schizophrenia. To understand the implications of this progressive neurobiology on brain function, we have developed a model in rats which we refer to as EDiPs (Enhanced Dopamine in Prodromal schizophrenia). The EDiPs model features a virally mediated increase in dorsal striatal (DS) DA synthesis capacity across puberty and into adulthood. This protocol leads to progressive changes in behaviour and neurochemistry. Our aim in this study was to explore if increased DA synthesis capacity alters the physiology of DA release and DS connectivity. Using fast scan cyclic voltammetry to assess DA release we show that evoked/phasic DA release is increased in the DS of EDiPs rats, whereas tonic/background levels of DA remain unaffected. Using quantitative immunohistochemistry methods to quantify DS synaptic architecture we show a presynaptic marker for DA release sites (Bassoon) was elevated within TH axons specifically within the DS, consistent with the increased phasic DA release in this region. Alongside changes in DA systems, we also show increased density of vesicular glutamate transporter 1 (VGluT1) synapses in the EDiPs DS suggesting changes in cortical connectivity. Our data may prove relevant in understanding the long-term implications for DS function in response to the robust and prolonged increases in DA synthesis uptake and release reported in schizophrenia.
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Affiliation(s)
- Sunil Srivastav
- Queensland Brain Institute, The University of Queensland, Brisbane, QLD, Australia
| | - Xiaoying Cui
- Queensland Brain Institute, The University of Queensland, Brisbane, QLD, Australia
- Queensland Centre for Mental Health Research, Brisbane, QLD, Australia
| | | | - James P Kesby
- Queensland Brain Institute, The University of Queensland, Brisbane, QLD, Australia
- Queensland Centre for Mental Health Research, Brisbane, QLD, Australia
| | - Darryl Eyles
- Queensland Brain Institute, The University of Queensland, Brisbane, QLD, Australia.
- Queensland Centre for Mental Health Research, Brisbane, QLD, Australia.
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21
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Nicoll RA, Schulman H. Synaptic memory and CaMKII. Physiol Rev 2023; 103:2877-2925. [PMID: 37290118 PMCID: PMC10642921 DOI: 10.1152/physrev.00034.2022] [Citation(s) in RCA: 16] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2022] [Revised: 04/26/2023] [Accepted: 04/30/2023] [Indexed: 06/10/2023] Open
Abstract
Ca2+/calmodulin-dependent protein kinase II (CaMKII) and long-term potentiation (LTP) were discovered within a decade of each other and have been inextricably intertwined ever since. However, like many marriages, it has had its up and downs. Based on the unique biochemical properties of CaMKII, it was proposed as a memory molecule before any physiological linkage was made to LTP. However, as reviewed here, the convincing linkage of CaMKII to synaptic physiology and behavior took many decades. New technologies were critical in this journey, including in vitro brain slices, mouse genetics, single-cell molecular genetics, pharmacological reagents, protein structure, and two-photon microscopy, as were new investigators attracted by the exciting challenge. This review tracks this journey and assesses the state of this marriage 40 years on. The collective literature impels us to propose a relatively simple model for synaptic memory involving the following steps that drive the process: 1) Ca2+ entry through N-methyl-d-aspartate (NMDA) receptors activates CaMKII. 2) CaMKII undergoes autophosphorylation resulting in constitutive, Ca2+-independent activity and exposure of a binding site for the NMDA receptor subunit GluN2B. 3) Active CaMKII translocates to the postsynaptic density (PSD) and binds to the cytoplasmic C-tail of GluN2B. 4) The CaMKII-GluN2B complex initiates a structural rearrangement of the PSD that may involve liquid-liquid phase separation. 5) This rearrangement involves the PSD-95 scaffolding protein, α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptors (AMPARs), and their transmembrane AMPAR-regulatory protein (TARP) auxiliary subunits, resulting in an accumulation of AMPARs in the PSD that underlies synaptic potentiation. 6) The stability of the modified PSD is maintained by the stability of the CaMKII-GluN2B complex. 7) By a process of subunit exchange or interholoenzyme phosphorylation CaMKII maintains synaptic potentiation in the face of CaMKII protein turnover. There are many other important proteins that participate in enlargement of the synaptic spine or modulation of the steps that drive and maintain the potentiation. In this review we critically discuss the data underlying each of the steps. As will become clear, some of these steps are more firmly grounded than others, and we provide suggestions as to how the evidence supporting these steps can be strengthened or, based on the new data, be replaced. Although the journey has been a long one, the prospect of having a detailed cellular and molecular understanding of learning and memory is at hand.
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Affiliation(s)
- Roger A Nicoll
- Department of Cellular and Molecular Pharmacology, University of California at San Francisco, San Francisco, California, United States
| | - Howard Schulman
- Department of Neurobiology, Stanford University School of Medicine, Stanford, California, United States
- Panorama Research Institute, Sunnyvale, California, United States
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22
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Ramsay HJ, Gookin SE, Ramsey AM, Kareemo DJ, Crosby KC, Stich DG, Olah SS, Actor-Engel HS, Smith KR, Kennedy MJ. AMPA and GABAA receptor nanodomains assemble in the absence of synaptic neurotransmitter release. Front Mol Neurosci 2023; 16:1232795. [PMID: 37602191 PMCID: PMC10435253 DOI: 10.3389/fnmol.2023.1232795] [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: 06/01/2023] [Accepted: 07/17/2023] [Indexed: 08/22/2023] Open
Abstract
Postsynaptic neurotransmitter receptors and their associated scaffolding proteins assemble into discrete, nanometer-scale subsynaptic domains (SSDs) within the postsynaptic membrane at both excitatory and inhibitory synapses. Intriguingly, postsynaptic receptor SSDs are mirrored by closely apposed presynaptic active zones. These trans-synaptic molecular assemblies are thought to be important for efficient neurotransmission because they concentrate postsynaptic receptors near sites of presynaptic neurotransmitter release. While previous studies have characterized the role of synaptic activity in sculpting the number, size, and distribution of postsynaptic SSDs at established synapses, it remains unknown whether neurotransmitter signaling is required for their initial assembly during synapse development. Here, we evaluated synaptic nano-architecture under conditions where presynaptic neurotransmitter release was blocked prior to, and throughout synaptogenesis with tetanus neurotoxin (TeNT). In agreement with previous work, neurotransmitter release was not required for the formation of excitatory or inhibitory synapses. The overall size of the postsynaptic specialization at both excitatory and inhibitory synapses was reduced at chronically silenced synapses. However, both AMPARs and GABAARs still coalesced into SSDs, along with their respective scaffold proteins. Presynaptic active zone assemblies, defined by RIM1, were smaller and more numerous at silenced synapses, but maintained alignment with postsynaptic AMPAR SSDs. Thus, basic features of synaptic nano-architecture, including assembly of receptors and scaffolds into trans-synaptically aligned structures, are intrinsic properties that can be further regulated by subsequent activity-dependent mechanisms.
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Affiliation(s)
- Harrison J. Ramsay
- Anschutz Medical Campus, Department of Pharmacology, University of Colorado, Aurora, CO, United States
| | - Sara E. Gookin
- Anschutz Medical Campus, Department of Pharmacology, University of Colorado, Aurora, CO, United States
| | - Austin M. Ramsey
- Anschutz Medical Campus, Department of Pharmacology, University of Colorado, Aurora, CO, United States
| | - Dean J. Kareemo
- Anschutz Medical Campus, Department of Pharmacology, University of Colorado, Aurora, CO, United States
| | - Kevin C. Crosby
- Anschutz Medical Campus, Department of Pharmacology, University of Colorado, Aurora, CO, United States
| | - Dominik G. Stich
- Anschutz Medical Campus, Advanced Light Microscopy Core, University of Colorado, Aurora, CO, United States
| | - Samantha S. Olah
- Anschutz Medical Campus, Department of Pharmacology, University of Colorado, Aurora, CO, United States
| | - Hannah S. Actor-Engel
- Anschutz Medical Campus, Department of Pharmacology, University of Colorado, Aurora, CO, United States
| | - Katharine R. Smith
- Anschutz Medical Campus, Department of Pharmacology, University of Colorado, Aurora, CO, United States
| | - Matthew J. Kennedy
- Anschutz Medical Campus, Department of Pharmacology, University of Colorado, Aurora, CO, United States
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23
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Woelfle S, Deshpande D, Feldengut S, Braak H, Del Tredici K, Roselli F, Deisseroth K, Michaelis J, Boeckers TM, Schön M. CLARITY increases sensitivity and specificity of fluorescence immunostaining in long-term archived human brain tissue. BMC Biol 2023; 21:113. [PMID: 37221592 PMCID: PMC10207789 DOI: 10.1186/s12915-023-01582-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2022] [Accepted: 03/29/2023] [Indexed: 05/25/2023] Open
Abstract
BACKGROUND Post mortem human brain tissue is an essential resource to study cell types, connectivity as well as subcellular structures down to the molecular setup of the central nervous system especially with respect to the plethora of brain diseases. A key method is immunostaining with fluorescent dyes, which allows high-resolution imaging in three dimensions of multiple structures simultaneously. Although there are large collections of formalin-fixed brains, research is often limited because several conditions arise that complicate the use of human brain tissue for high-resolution fluorescence microscopy. RESULTS In this study, we developed a clearing approach for immunofluorescence-based analysis of perfusion- and immersion-fixed post mortem human brain tissue, termed human Clear Lipid-exchanged Acrylamide-hybridized Rigid Imaging / Immunostaining / In situ hybridization-compatible Tissue-hYdrogel (hCLARITY). hCLARITY is optimized for specificity by reducing off-target labeling and yields very sensitive stainings in human brain sections allowing for super-resolution microscopy with unprecedented imaging of pre- and postsynaptic compartments. Moreover, hallmarks of Alzheimer's disease were preserved with hCLARITY, and importantly classical 3,3'-diaminobenzidine (DAB) or Nissl stainings are compatible with this protocol. hCLARITY is very versatile as demonstrated by the use of more than 30 well performing antibodies and allows for de- and subsequent re-staining of the same tissue section, which is important for multi-labeling approaches, e.g., in super-resolution microscopy. CONCLUSIONS Taken together, hCLARITY enables research of the human brain with high sensitivity and down to sub-diffraction resolution. It therefore has enormous potential for the investigation of local morphological changes, e.g., in neurodegenerative diseases.
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Affiliation(s)
- Sarah Woelfle
- Institute for Anatomy and Cell Biology, Ulm University, Albert-Einstein-Allee 11, 89081, Ulm, Germany
- International Graduate School in Molecular Medicine Ulm, IGradU, 89081, Ulm, Germany
| | - Dhruva Deshpande
- Institute of Biophysics, Ulm University, Albert-Einstein-Allee 11, 89081, Ulm, Germany
- Chemical and Systems Biology Department, Stanford School of Medicine, 269 Campus Drive, Stanford, CA, 94305, USA
| | - Simone Feldengut
- Clinical Neuroanatomy Section/Department of Neurology, Center for Biomedical Research, Ulm University, Helmholtzstraße 8/1, 89081, Ulm, Germany
| | - Heiko Braak
- Clinical Neuroanatomy Section/Department of Neurology, Center for Biomedical Research, Ulm University, Helmholtzstraße 8/1, 89081, Ulm, Germany
| | - Kelly Del Tredici
- Clinical Neuroanatomy Section/Department of Neurology, Center for Biomedical Research, Ulm University, Helmholtzstraße 8/1, 89081, Ulm, Germany
| | - Francesco Roselli
- Department of Neurology, Ulm University, 89081, Ulm, Germany
- Deutsches Zentrum für Neurodegenerative Erkrankungen, DZNE, Ulm Site, 89081, Ulm, Germany
| | - Karl Deisseroth
- Department of Bioengineering, Stanford University, Stanford, CA, 94305, USA
- Department of Psychiatry and Behavioral Sciences, Stanford University, Stanford, CA, 94305, USA
- Howard Hughes Medical Institute, Stanford, CA, 94305, USA
| | - Jens Michaelis
- Institute of Biophysics, Ulm University, Albert-Einstein-Allee 11, 89081, Ulm, Germany
| | - Tobias M Boeckers
- Institute for Anatomy and Cell Biology, Ulm University, Albert-Einstein-Allee 11, 89081, Ulm, Germany
- Deutsches Zentrum für Neurodegenerative Erkrankungen, DZNE, Ulm Site, 89081, Ulm, Germany
| | - Michael Schön
- Institute for Anatomy and Cell Biology, Ulm University, Albert-Einstein-Allee 11, 89081, Ulm, Germany.
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24
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Minegishi T, Kastian RF, Inagaki N. Mechanical regulation of synapse formation and plasticity. Semin Cell Dev Biol 2023; 140:82-89. [PMID: 35659473 DOI: 10.1016/j.semcdb.2022.05.017] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2022] [Revised: 05/10/2022] [Accepted: 05/17/2022] [Indexed: 01/28/2023]
Abstract
Dendritic spines are small protrusions arising from dendrites and constitute the major compartment of excitatory post-synapses. They change in number, shape, and size throughout life; these changes are thought to be associated with formation and reorganization of neuronal networks underlying learning and memory. As spines in the brain are surrounded by the microenvironment including neighboring cells and the extracellular matrix, their protrusion requires generation of force to push against these structures. In turn, neighboring cells receive force from protruding spines. Recent studies have identified BAR-domain proteins as being involved in membrane deformation to initiate spine formation. In addition, forces for dendritic filopodium extension and activity-induced spine expansion are generated through cooperation between actin polymerization and clutch coupling. On the other hand, force from expanding spines affects neurotransmitter release from presynaptic terminals. Here, we review recent advances in our understanding of the physical aspects of synapse formation and plasticity, mainly focusing on spine dynamics.
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Affiliation(s)
- Takunori Minegishi
- Laboratory of Systems Neurobiology and Medicine, Division of Biological Science, Nara Institute of Science and Technology, Ikoma, Nara 630-0192, Japan
| | - Ria Fajarwati Kastian
- Laboratory of Systems Neurobiology and Medicine, Division of Biological Science, Nara Institute of Science and Technology, Ikoma, Nara 630-0192, Japan; Research Center for Genetic Engineering, National Research and Innovation Agency Republic of Indonesia, Cibinong, Bogor, Indonesia
| | - Naoyuki Inagaki
- Laboratory of Systems Neurobiology and Medicine, Division of Biological Science, Nara Institute of Science and Technology, Ikoma, Nara 630-0192, Japan.
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25
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Li BZ, Sumera A, Booker SA, McCullagh EA. Current Best Practices for Analysis of Dendritic Spine Morphology and Number in Neurodevelopmental Disorder Research. ACS Chem Neurosci 2023; 14:1561-1572. [PMID: 37070364 PMCID: PMC10161226 DOI: 10.1021/acschemneuro.3c00062] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2023] [Accepted: 04/07/2023] [Indexed: 04/19/2023] Open
Abstract
Quantitative methods for assessing neural anatomy have rapidly evolved in neuroscience and provide important insights into brain health and function. However, as new techniques develop, it is not always clear when and how each may be used to answer specific scientific questions posed. Dendritic spines, which are often indicative of synapse formation and neural plasticity, have been implicated across many brain regions in neurodevelopmental disorders as a marker for neural changes reflecting neural dysfunction or alterations. In this Perspective we highlight several techniques for staining, imaging, and quantifying dendritic spines as well as provide a framework for avoiding potential issues related to pseudoreplication. This framework illustrates how others may apply the most rigorous approaches. We consider the cost-benefit analysis of the varied techniques, recognizing that the most sophisticated equipment may not always be necessary for answering some research questions. Together, we hope this piece will help researchers determine the best strategy toward using the ever-growing number of techniques available to determine neural changes underlying dendritic spine morphology in health and neurodevelopmental disorders.
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Affiliation(s)
- Ben-Zheng Li
- Department
of Physiology and Biophysics, University
of Colorado Anschutz Medical Campus, Aurora, Colorado 80045, United States
| | - Anna Sumera
- Simons
Initiative for the Developing Brain, Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh EH8 9XD, U.K.
| | - Sam A Booker
- Simons
Initiative for the Developing Brain, Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh EH8 9XD, U.K.
| | - Elizabeth A. McCullagh
- Department
of Integrative Biology, Oklahoma State University, Stillwater, Oklahoma 74078, United States
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26
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Wang J, Wang J, Wang Y, Chai Y, Li H, Miao D, Liu H, Li J, Bao J. Music with Different Tones Affects the Development of Brain Nerves in Mice in Early Life through BDNF and Its Downstream Pathways. Int J Mol Sci 2023; 24:ijms24098119. [PMID: 37175826 PMCID: PMC10179650 DOI: 10.3390/ijms24098119] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2023] [Revised: 04/15/2023] [Accepted: 04/28/2023] [Indexed: 05/15/2023] Open
Abstract
As a means of environmental enrichment, music environment has positive and beneficial effects on biological neural development. Kunming white mice (61 days old) were randomly divided into the control group (group C), the group of D-tone (group D), the group of A-tone (group A) and the group of G-tone (group G). They were given different tonal music stimulation (group A) for 14 consecutive days (2 h/day) to study the effects of tonal music on the neural development of the hippocampus and prefrontal cortex of mice in early life and its molecular mechanisms. The results showed that the number of neurons in the hippocampus and prefrontal cortex of mice increased, with the cell morphology relatively intact. In addition, the number of dendritic spines and the number of dendritic spines per unit length were significantly higher than those in group C, and the expressions of synaptic plasticity proteins (SYP and PSD95) were also significantly elevated over those in group C. Compared with group C, the expression levels of BDNF, TRKB, CREB, PI3K, AKT, GS3Kβ, PLCγ1, PKC, DAG, ERK and MAPK genes and proteins in the hippocampus and prefrontal cortex of mice in the music groups were up-regulated, suggesting that different tones of music could regulate neural development through BDNF and its downstream pathways. The enrichment environment of D-tone music is the most suitable tone for promoting the development of brain nerves in early-life mice. Our study provides a basis for screening the optimal tone of neuroplasticity in early-life mice and for the treatment of neurobiology and neurodegenerative diseases.
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Affiliation(s)
- Jing Wang
- College of Life Science, Northeast Agricultural University, Harbin 150030, China
| | - Jianxing Wang
- College of Life Science, Northeast Agricultural University, Harbin 150030, China
| | - Yulai Wang
- College of Animal Science and Technology, Northeast Agricultural University, Harbin 150030, China
| | - Yiwen Chai
- College of Life Science, Northeast Agricultural University, Harbin 150030, China
| | - Haochen Li
- College of Life Science, Northeast Agricultural University, Harbin 150030, China
| | - Deyang Miao
- College of Life Science, Northeast Agricultural University, Harbin 150030, China
| | - Honggui Liu
- College of Animal Science and Technology, Northeast Agricultural University, Harbin 150030, China
| | - Jianhong Li
- College of Life Science, Northeast Agricultural University, Harbin 150030, China
| | - Jun Bao
- College of Life Science, Northeast Agricultural University, Harbin 150030, China
- College of Animal Science and Technology, Northeast Agricultural University, Harbin 150030, China
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27
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Bessa-Neto D, Choquet D. Molecular mechanisms of AMPAR reversible stabilization at synapses. Mol Cell Neurosci 2023; 125:103856. [PMID: 37105372 DOI: 10.1016/j.mcn.2023.103856] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2022] [Revised: 04/17/2023] [Accepted: 04/19/2023] [Indexed: 04/29/2023] Open
Abstract
In the central nervous system, glutamatergic synapses play a central role in the regulation of excitatory neuronal transmission. With the membrane-associated guanylate kinase (MAGUK) family of proteins as their structuring scaffold, glutamatergic receptors serve as the powerhouse of glutamatergic synapses. Glutamatergic receptors can be categorized as metabotropic and ionotropic receptors. The latter are then categorized into N-methyl-d-aspartate, kainate receptors, and α-amino-3-hydroxy-5-methyl-isoxazole-propionic acid receptors (AMPARs). Over the past two decades, genetic tagging technology and super-resolution microscopy have been of the utmost importance to unravel how the different receptors are organized at glutamatergic synapses. At the plasma membrane, receptors are highly mobile but show reduced mobility when at synaptic sites. This partial immobilization of receptors at synaptic sites is attributed to the stabilization/anchoring of receptors with the postsynaptic MAGUK proteins and auxiliary proteins, and presynaptic proteins. These partial immobilizations and localization of glutamatergic receptors within the synaptic sites are fundamental for proper basal transmission and synaptic plasticity. Perturbations of the stabilization of glutamatergic receptors are often associated with cognitive deficits. In this review, we describe the proposed mechanisms for synaptic localization and stabilization of AMPARs, the major players of fast excitatory transmission in the central nervous system.
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Affiliation(s)
- Diogo Bessa-Neto
- Univ. Bordeaux, CNRS, Interdisciplinary Institute for Neuroscience, IINS, UMR 5297, F-33000 Bordeaux, France
| | - Daniel Choquet
- Univ. Bordeaux, CNRS, Interdisciplinary Institute for Neuroscience, IINS, UMR 5297, F-33000 Bordeaux, France; Univ. Bordeaux, CNRS, INSERM, Bordeaux Imaging Center, BIC, UMS 3420, US 4, F-33000 Bordeaux, France.
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28
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Jung JH, Chen X, Reese TS. Cryo-EM tomography and automatic segmentation delineate modular structures in the postsynaptic density. Front Synaptic Neurosci 2023; 15:1123564. [PMID: 37091879 PMCID: PMC10117989 DOI: 10.3389/fnsyn.2023.1123564] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2022] [Accepted: 03/02/2023] [Indexed: 04/08/2023] Open
Abstract
Postsynaptic densities (PSDs) are large protein complexes associated with the postsynaptic membrane of excitatory synapses important for synaptic function including plasticity. Conventional electron microscopy (EM) typically depicts PSDs as compact disk-like structures of hundreds of nanometers in size. Biochemically isolated PSDs were also similar in dimension revealing a predominance of proteins with the ability to polymerize into an extensive scaffold; several EM studies noted their irregular contours with often small granular structures (<30 nm) and holes. Super-resolution light microscopy studies observed clusters of PSD elements and their activity-induced lateral movement. Furthermore, our recent EM study on PSD fractions after sonication observed PSD fragments (40–90 nm in size) separate from intact PSDs; however, such structures within PSDs remained unidentified. Here we examined isolated PSDs by cryo-EM tomography with our new approach of automatic segmentation that enables delineation of substructures and their quantitative analysis. The delineated substructures broadly varied in size, falling behind 30 nm or exceeding 100 nm and showed that a considerable portion of the substructures (>38%) in isolated PSDs was in the same size range as those fragments. Furthermore, substructures spanning the entire thickness of the PSD were found, large enough to contain both membrane-associated and cytoplasmic proteins of the PSD; interestingly, they were similar to nanodomains in frequency. The structures detected here appear to constitute the isolated PSD as modules of various compositions, and this modular nature may facilitate remodeling of the PSD for proper synaptic function and plasticity.
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29
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Kudryashova I. Presynaptic Plasticity Is Associated with Actin Polymerization. BIOCHEMISTRY (MOSCOW) 2023; 88:392-403. [PMID: 37076285 DOI: 10.1134/s0006297923030082] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/29/2023]
Abstract
Modulation of presynaptic short-term plasticity induced by actin polymerization was studied in rat hippocampal slices using the paired-pulse paradigm. Schaffer collaterals were stimulated with paired pulses with a 70-ms interstimulus interval every 30 s before and during perfusion with jasplakinolide, an activator of actin polymerization. Jasplakinolide application resulted in the increase in the amplitudes of CA3-CA1 responses (potentiation) accompanied by a decrease in the paired-pulse facilitation, suggesting induction of presynaptic modifications. Jasplakinolide-induced potentiation depended on the initial paired-pulse rate. These data indicate that the jasplakinolide-mediated changes in actin polymerization increased the probability of neurotransmitter release. Less typical for CA3-CA1 synapses responses, such as a very low paired-pulse ratio (close to 1 or even lower) or even paired-pulse depression, were affected differently. Thus, jasplakinolide caused potentiation of the second, but not the first response to the paired stimulus, which increased the paired-pulse ratio from 0.8 to 1.0 on average, suggesting a negative impact of jasplakinolide on the mechanisms promoting paired-pulse depression. In general, actin polymerization facilitated potentiation, although the patterns of potentiation differed depending on the initial synapse characteristics. We conclude that in addition to the increase in the neurotransmitter release probability, jasplakinolide induced other actin polymerization-dependent mechanisms, including those involved in the paired-pulse depression.
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Affiliation(s)
- Irina Kudryashova
- Laboratory of Functional Biochemistry of the Nervous System, Institute of Higher Nervous Activity and Neurophysiology, Russian Academy of Sciences, Moscow, 119991, Russia.
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30
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Droogers WJ, MacGillavry HD. Plasticity of postsynaptic nanostructure. Mol Cell Neurosci 2023; 124:103819. [PMID: 36720293 DOI: 10.1016/j.mcn.2023.103819] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2022] [Revised: 01/19/2023] [Accepted: 01/23/2023] [Indexed: 01/31/2023] Open
Abstract
The postsynaptic density (PSD) of excitatory synapses is built from a wide variety of scaffolding proteins, receptors, and signaling molecules that collectively orchestrate synaptic transmission. Seminal work over the past decades has led to the identification and functional characterization of many PSD components. In contrast, we know far less about how these constituents are assembled within synapses, and how this organization contributes to synapse function. Notably, recent evidence from high-resolution microscopy studies and in silico models, highlights the importance of the precise subsynaptic structure of the PSD for controlling the strength of synaptic transmission. Even further, activity-driven changes in the distribution of glutamate receptors are acknowledged to contribute to long-term changes in synaptic efficacy. Thus, defining the mechanisms that drive structural changes within the PSD are important for a molecular understanding of synaptic transmission and plasticity. Here, we review the current literature on how the PSD is organized to mediate basal synaptic transmission and how synaptic activity alters the nanoscale organization of synapses to sustain changes in synaptic strength.
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Affiliation(s)
- W J Droogers
- Division of Cell Biology, Neurobiology and Biophysics, Department of Biology, Faculty of Science, Utrecht University, 3584 CH, The Netherlands
| | - H D MacGillavry
- Division of Cell Biology, Neurobiology and Biophysics, Department of Biology, Faculty of Science, Utrecht University, 3584 CH, The Netherlands.
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31
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Quantitative Fluorescence Analysis Reveals Dendrite-Specific Thalamocortical Plasticity in L5 Pyramidal Neurons during Learning. J Neurosci 2023; 43:584-600. [PMID: 36639912 PMCID: PMC9888508 DOI: 10.1523/jneurosci.1372-22.2022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2022] [Revised: 10/28/2022] [Accepted: 11/23/2022] [Indexed: 12/14/2022] Open
Abstract
High-throughput anatomic data can stimulate and constrain new hypotheses about how neural circuits change in response to experience. Here, we use fluorescence-based reagents for presynaptic and postsynaptic labeling to monitor changes in thalamocortical synapses onto different compartments of layer 5 (L5) pyramidal (Pyr) neurons in somatosensory (barrel) cortex from mixed-sex mice during whisker-dependent learning (Audette et al., 2019). Using axonal fills and molecular-genetic tags for synapse identification in fixed tissue from Rbp4-Cre transgenic mice, we found that thalamocortical synapses from the higher-order posterior medial thalamic nucleus showed rapid morphologic changes in both presynaptic and postsynaptic structures at the earliest stages of sensory association training. Detected increases in thalamocortical synaptic size were compartment specific, occurring selectively in the proximal dendrites onto L5 Pyr and not at inputs onto their apical tufts in L1. Both axonal and dendritic changes were transient, normalizing back to baseline as animals became expert in the task. Anatomical measurements were corroborated by electrophysiological recordings at different stages of training. Thus, fluorescence-based analysis of input- and target-specific synapses can reveal compartment-specific changes in synapse properties during learning.SIGNIFICANCE STATEMENT Synaptic changes underlie the cellular basis of learning, experience, and neurologic diseases. Neuroanatomical methods to assess synaptic plasticity can provide critical spatial information necessary for building models of neuronal computations during learning and experience but are technically and fiscally intensive. Here, we describe a confocal fluorescence microscopy-based analytical method to assess input, cell type, and dendritic location-specific synaptic plasticity in a sensory learning assay. Our method not only confirms prior electrophysiological measurements but allows us to predict functional strength of synapses in a pathway-specific manner. Our findings also indicate that changes in primary sensory cortices are transient, occurring during early learning. Fluorescence-based synapse identification can be an efficient and easily adopted approach to study synaptic changes in a variety of experimental paradigms.
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32
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Quantifying postsynaptic receptor dynamics: insights into synaptic function. Nat Rev Neurosci 2023; 24:4-22. [PMID: 36352031 DOI: 10.1038/s41583-022-00647-9] [Citation(s) in RCA: 12] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/28/2022] [Indexed: 11/11/2022]
Abstract
The molecular composition of presynaptic and postsynaptic neuronal terminals is dynamic, and yet long-term stabilizations in postsynaptic responses are necessary for synaptic development and long-term plasticity. The need to reconcile these concepts is further complicated by learning- and memory-related plastic changes in the molecular make-up of synapses. Advances in single-particle tracking mean that we can now quantify the number and diffusive properties of specific synaptic molecules, while statistical thermodynamics provides a framework to analyse these molecular fluctuations. In this Review, we discuss the use of these approaches to gain quantitative descriptions of the processes underlying the turnover, long-term stability and plasticity of postsynaptic receptors and show how these can help us to understand the balance between local molecular turnover and synaptic structural identity and integrity.
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KASAI H. Unraveling the mysteries of dendritic spine dynamics: Five key principles shaping memory and cognition. PROCEEDINGS OF THE JAPAN ACADEMY. SERIES B, PHYSICAL AND BIOLOGICAL SCIENCES 2023; 99:254-305. [PMID: 37821392 PMCID: PMC10749395 DOI: 10.2183/pjab.99.018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/13/2023] [Accepted: 07/11/2023] [Indexed: 10/13/2023]
Abstract
Recent research extends our understanding of brain processes beyond just action potentials and chemical transmissions within neural circuits, emphasizing the mechanical forces generated by excitatory synapses on dendritic spines to modulate presynaptic function. From in vivo and in vitro studies, we outline five central principles of synaptic mechanics in brain function: P1: Stability - Underpinning the integral relationship between the structure and function of the spine synapses. P2: Extrinsic dynamics - Highlighting synapse-selective structural plasticity which plays a crucial role in Hebbian associative learning, distinct from pathway-selective long-term potentiation (LTP) and depression (LTD). P3: Neuromodulation - Analyzing the role of G-protein-coupled receptors, particularly dopamine receptors, in time-sensitive modulation of associative learning frameworks such as Pavlovian classical conditioning and Thorndike's reinforcement learning (RL). P4: Instability - Addressing the intrinsic dynamics crucial to memory management during continual learning, spotlighting their role in "spine dysgenesis" associated with mental disorders. P5: Mechanics - Exploring how synaptic mechanics influence both sides of synapses to establish structural traces of short- and long-term memory, thereby aiding the integration of mental functions. We also delve into the historical background and foresee impending challenges.
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Affiliation(s)
- Haruo KASAI
- International Research Center for Neurointelligence (WPI-IRCN), UTIAS, The University of Tokyo, Bunkyo-ku, Tokyo, Japan
- Laboratory of Structural Physiology, Center for Disease Biology and Integrative Medicine, Faculty of Medicine, The University of Tokyo, Bunkyo-ku, Tokyo, Japan
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Uchigashima M, Hayashi Y, Futai K. Regulation of Presynaptic Release Machinery by Cell Adhesion Molecules. ADVANCES IN NEUROBIOLOGY 2023; 33:333-356. [PMID: 37615873 DOI: 10.1007/978-3-031-34229-5_13] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/25/2023]
Abstract
The synapse is a highly specialized asymmetric structure that transmits and stores information in the brain. The size of pre- and postsynaptic structures and function is well coordinated at the individual synapse level. For example, large postsynaptic dendritic spines have a larger postsynaptic density with higher α-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid receptor (AMPAR) number on their surface, while juxtaposing presynaptic terminals have a larger active zone and higher release probability. This indicates that pre- and postsynaptic domains bidirectionally communicate to coordinate assembly of specific molecules on both sides of the synaptic cleft. Cell adhesion molecules (CAMs) that localize at synapses form transsynaptic protein interactions across the synaptic cleft and play important roles in synapse formation and regulation. The extracellular domain of CAMs is essential for specific synapse formation and function. In contrast, the intracellular domain is necessary for binding with synaptic molecules and signal transduction. Therefore, CAMs play an essential role on synapse function and structure. In fact, ample evidence indicates that transsynaptic CAMs instruct and modulate functions at presynaptic sites. This chapter focuses on transsynaptic protein interactions that regulate presynaptic functions emphasizing the role of neuronal CAMs and the intracellular mechanism of their regulation.
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Affiliation(s)
- Motokazu Uchigashima
- Department of Cellular Neuropathology, Brain Research Institute, Niigata University, Niigata, Japan
| | - Yasunori Hayashi
- Department of Pharmacology, Kyoto University Graduate School of Medicine, Kyoto, Japan
| | - Kensuke Futai
- Brudnick Neuropsychiatric Research Institute, Department of Neurobiology, University of Massachusetts Chan Medical School, Worcester, MA, USA.
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Fyn nanoclustering requires switching to an open conformation and is enhanced by FTLD-Tau biomolecular condensates. Mol Psychiatry 2023; 28:946-962. [PMID: 36258016 PMCID: PMC9908554 DOI: 10.1038/s41380-022-01825-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/19/2021] [Revised: 09/19/2022] [Accepted: 09/27/2022] [Indexed: 11/08/2022]
Abstract
Fyn is a Src kinase that controls critical signalling cascades and has been implicated in learning and memory. Postsynaptic enrichment of Fyn underpins synaptotoxicity in dementias such as Alzheimer's disease and frontotemporal lobar degeneration with Tau pathology (FTLD-Tau). The FLTD P301L mutant Tau is associated with a higher propensity to undergo liquid-liquid phase separation (LLPS) and form biomolecular condensates. Expression of P301L mutant Tau promotes aberrant trapping of Fyn in nanoclusters within hippocampal dendrites by an unknown mechanism. Here, we used single-particle tracking photoactivated localisation microscopy to demonstrate that the opening of Fyn into its primed conformation promotes its nanoclustering in dendrites leading to increased Fyn/ERK/S6 downstream signalling. Preventing the auto-inhibitory closed conformation of Fyn through phospho-inhibition or through perturbation of its SH3 domain increased Fyn's nanoscale trapping, whereas inhibition of the catalytic domain had no impact. By combining pharmacological and genetic approaches, we demonstrate that P301L Tau enhanced both Fyn nanoclustering and Fyn/ERK/S6 signalling via its ability to form biomolecular condensates. Together, our findings demonstrate that Fyn alternates between a closed and an open conformation, the latter being enzymatically active and clustered. Furthermore, pathogenic immobilisation of Fyn relies on the ability of P301L Tau to form biomolecular condensates, thus highlighting the critical importance of LLPS in controlling nanoclustering and downstream intracellular signalling events.
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36
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Renner J, Rasia-Filho AA. Morphological Features of Human Dendritic Spines. ADVANCES IN NEUROBIOLOGY 2023; 34:367-496. [PMID: 37962801 DOI: 10.1007/978-3-031-36159-3_9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2023]
Abstract
Dendritic spine features in human neurons follow the up-to-date knowledge presented in the previous chapters of this book. Human dendrites are notable for their heterogeneity in branching patterns and spatial distribution. These data relate to circuits and specialized functions. Spines enhance neuronal connectivity, modulate and integrate synaptic inputs, and provide additional plastic functions to microcircuits and large-scale networks. Spines present a continuum of shapes and sizes, whose number and distribution along the dendritic length are diverse in neurons and different areas. Indeed, human neurons vary from aspiny or "relatively aspiny" cells to neurons covered with a high density of intermingled pleomorphic spines on very long dendrites. In this chapter, we discuss the phylogenetic and ontogenetic development of human spines and describe the heterogeneous features of human spiny neurons along the spinal cord, brainstem, cerebellum, thalamus, basal ganglia, amygdala, hippocampal regions, and neocortical areas. Three-dimensional reconstructions of Golgi-impregnated dendritic spines and data from fluorescence microscopy are reviewed with ultrastructural findings to address the complex possibilities for synaptic processing and integration in humans. Pathological changes are also presented, for example, in Alzheimer's disease and schizophrenia. Basic morphological data can be linked to current techniques, and perspectives in this research field include the characterization of spines in human neurons with specific transcriptome features, molecular classification of cellular diversity, and electrophysiological identification of coexisting subpopulations of cells. These data would enlighten how cellular attributes determine neuron type-specific connectivity and brain wiring for our diverse aptitudes and behavior.
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Affiliation(s)
- Josué Renner
- Department of Basic Sciences/Physiology and Graduate Program in Biosciences, Universidade Federal de Ciências da Saúde de Porto Alegre, Porto Alegre, RS, Brazil
| | - Alberto A Rasia-Filho
- Department of Basic Sciences/Physiology and Graduate Program in Biosciences, Universidade Federal de Ciências da Saúde de Porto Alegre, Porto Alegre, RS, Brazil
- Graduate Program in Neuroscience, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil
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Rho-Kinase/ROCK Phosphorylates PSD-93 Downstream of NMDARs to Orchestrate Synaptic Plasticity. Int J Mol Sci 2022; 24:ijms24010404. [PMID: 36613848 PMCID: PMC9820267 DOI: 10.3390/ijms24010404] [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: 11/18/2022] [Revised: 12/21/2022] [Accepted: 12/23/2022] [Indexed: 12/28/2022] Open
Abstract
The N-methyl-D-aspartate receptor (NMDAR)-mediated structural plasticity of dendritic spines plays an important role in synaptic transmission in the brain during learning and memory formation. The Rho family of small GTPase RhoA and its downstream effector Rho-kinase/ROCK are considered as one of the major regulators of synaptic plasticity and dendritic spine formation, including long-term potentiation (LTP). However, the mechanism by which Rho-kinase regulates synaptic plasticity is not yet fully understood. Here, we found that Rho-kinase directly phosphorylated discs large MAGUK scaffold protein 2 (DLG2/PSD-93), a major postsynaptic scaffold protein that connects postsynaptic proteins with NMDARs; an ionotropic glutamate receptor, which plays a critical role in synaptic plasticity. Stimulation of striatal slices with an NMDAR agonist induced Rho-kinase-mediated phosphorylation of PSD-93 at Thr612. We also identified PSD-93-interacting proteins, including DLG4 (PSD-95), NMDARs, synaptic Ras GTPase-activating protein 1 (SynGAP1), ADAM metallopeptidase domain 22 (ADAM22), and leucine-rich glioma-inactivated 1 (LGI1), by liquid chromatography-tandem mass spectrometry (LC-MS/MS). Among them, Rho-kinase increased the binding of PSD-93 to PSD-95 and NMDARs. Furthermore, we found that chemical-LTP induced by glycine, which activates NMDARs, increased PSD-93 phosphorylation at Thr612, spine size, and PSD-93 colocalization with PSD-95, while these events were blocked by pretreatment with a Rho-kinase inhibitor. These results indicate that Rho-kinase phosphorylates PSD-93 downstream of NMDARs, and suggest that Rho-kinase mediated phosphorylation of PSD-93 increases the association with PSD-95 and NMDARs to regulate structural synaptic plasticity.
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Hassani Nia F, Woike D, Bento I, Niebling S, Tibbe D, Schulz K, Hirnet D, Skiba M, Hönck HH, Veith K, Günther C, Scholz T, Bierhals T, Driemeyer J, Bend R, Failla AV, Lohr C, Alai MG, Kreienkamp HJ. Structural deficits in key domains of Shank2 lead to alterations in postsynaptic nanoclusters and to a neurodevelopmental disorder in humans. Mol Psychiatry 2022:10.1038/s41380-022-01882-3. [PMID: 36450866 DOI: 10.1038/s41380-022-01882-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/01/2022] [Revised: 11/02/2022] [Accepted: 11/10/2022] [Indexed: 12/05/2022]
Abstract
Postsynaptic scaffold proteins such as Shank, PSD-95, Homer and SAPAP/GKAP family members establish the postsynaptic density of glutamatergic synapses through a dense network of molecular interactions. Mutations in SHANK genes are associated with neurodevelopmental disorders including autism and intellectual disability. However, no SHANK missense mutations have been described which interfere with the key functions of Shank proteins believed to be central for synapse formation, such as GKAP binding via the PDZ domain, or Zn2+-dependent multimerization of the SAM domain. We identify two individuals with a neurodevelopmental disorder carrying de novo missense mutations in SHANK2. The p.G643R variant distorts the binding pocket for GKAP in the Shank2 PDZ domain and prevents interaction with Thr(-2) in the canonical PDZ ligand motif of GKAP. The p.L1800W variant severely delays the kinetics of Zn2+-dependent polymerization of the Shank2-SAM domain. Structural analysis shows that Trp1800 dislodges one histidine crucial for Zn2+ binding. The resulting conformational changes block the stacking of helical polymers of SAM domains into sheets through side-by-side contacts, which is a hallmark of Shank proteins, thereby disrupting the highly cooperative assembly process induced by Zn2+. Both variants reduce the postsynaptic targeting of Shank2 in primary cultured neurons and alter glutamatergic synaptic transmission. Super-resolution microscopy shows that both mutants interfere with the formation of postsynaptic nanoclusters. Our data indicate that both the PDZ- and the SAM-mediated interactions of Shank2 contribute to the compaction of postsynaptic protein complexes into nanoclusters, and that deficiencies in this process interfere with normal brain development in humans.
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Affiliation(s)
- Fatemeh Hassani Nia
- Institute for Human Genetics, University Medical Center Hamburg Eppendorf, Hamburg, Germany
| | - Daniel Woike
- Institute for Human Genetics, University Medical Center Hamburg Eppendorf, Hamburg, Germany
| | | | - Stephan Niebling
- EMBL Hamburg, c/o DESY, Hamburg, Germany
- Centre for Structural Systems Biology, Hamburg, Germany
| | - Debora Tibbe
- Institute for Human Genetics, University Medical Center Hamburg Eppendorf, Hamburg, Germany
| | - Kristina Schulz
- Institute of Cell and Systems Biology of Animals, University of Hamburg, Hamburg, Germany
- III. Department of Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Daniela Hirnet
- Institute of Cell and Systems Biology of Animals, University of Hamburg, Hamburg, Germany
| | - Matilda Skiba
- Institute of Cell and Systems Biology of Animals, University of Hamburg, Hamburg, Germany
| | - Hans-Hinrich Hönck
- Institute for Human Genetics, University Medical Center Hamburg Eppendorf, Hamburg, Germany
| | | | | | - Tasja Scholz
- Institute for Human Genetics, University Medical Center Hamburg Eppendorf, Hamburg, Germany
| | - Tatjana Bierhals
- Institute for Human Genetics, University Medical Center Hamburg Eppendorf, Hamburg, Germany
| | - Joenna Driemeyer
- Department of Pediatrics, University Medical Center Eppendorf, Hamburg, Germany
| | - Renee Bend
- Prevention Genetics, Marshfield, WI, USA
| | - Antonio Virgilio Failla
- UKE microscopic imaging facility (umif), University Medical Center Eppendorf, Hamburg, Germany
| | - Christian Lohr
- Institute of Cell and Systems Biology of Animals, University of Hamburg, Hamburg, Germany
| | - Maria Garcia Alai
- EMBL Hamburg, c/o DESY, Hamburg, Germany
- Centre for Structural Systems Biology, Hamburg, Germany
| | - Hans-Jürgen Kreienkamp
- Institute for Human Genetics, University Medical Center Hamburg Eppendorf, Hamburg, Germany.
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39
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Abstract
Robust neural information transfer relies on a delicate molecular nano-architecture of chemical synapses. Neurotransmitter release is controlled by a specific arrangement of proteins within presynaptic active zones. How the specific presynaptic molecular architecture relates to postsynaptic organization and how synaptic nano-architecture is transsynaptically regulated to enable stable synaptic transmission remain enigmatic. Using time-gated stimulated emission-depletion microscopy at the Drosophila neuromuscular junction, we found that presynaptic nanorings formed by the active-zone scaffold Bruchpilot (Brp) align with postsynaptic glutamate receptor (GluR) rings. Individual rings harbor approximately four transsynaptically aligned Brp-GluR nanocolumns. Similar nanocolumn rings are formed by the presynaptic protein Unc13A and GluRs. Intriguingly, acute GluR impairment triggers transsynaptic nanocolumn formation on the minute timescale during homeostatic plasticity. We reveal distinct phases of structural transsynaptic homeostatic plasticity, with postsynaptic GluR reorganization preceding presynaptic Brp modulation. Finally, homeostatic control of transsynaptic nano-architecture and neurotransmitter release requires the auxiliary GluR subunit Neto. Thus, transsynaptic nanocolumn rings provide a substrate for rapid homeostatic stabilization of synaptic efficacy.
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40
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Chen X, Crosby KC, Feng A, Purkey AM, Aronova MA, Winters CA, Crocker VT, Leapman RD, Reese TS, Dell’Acqua ML. Palmitoylation of A-kinase anchoring protein 79/150 modulates its nanoscale organization, trafficking, and mobility in postsynaptic spines. Front Synaptic Neurosci 2022; 14:1004154. [PMID: 36186623 PMCID: PMC9521714 DOI: 10.3389/fnsyn.2022.1004154] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2022] [Accepted: 08/23/2022] [Indexed: 11/29/2022] Open
Abstract
A-kinase anchoring protein 79-human/150-rodent (AKAP79/150) organizes signaling proteins to control synaptic plasticity. AKAP79/150 associates with the plasma membrane and endosomes through its N-terminal domain that contains three polybasic regions and two Cys residues that are reversibly palmitoylated. Mutations abolishing palmitoylation (AKAP79/150 CS) reduce its endosomal localization and association with the postsynaptic density (PSD). Here we combined advanced light and electron microscopy (EM) to characterize the effects of AKAP79/150 palmitoylation on its postsynaptic nanoscale organization, trafficking, and mobility in hippocampal neurons. Immunogold EM revealed prominent extrasynaptic membrane AKAP150 labeling with less labeling at the PSD. The label was at greater distances from the spine membrane for AKAP150 CS than WT in the PSD but not in extra-synaptic locations. Immunogold EM of GFP-tagged AKAP79 WT showed that AKAP79 adopts a vertical, extended conformation at the PSD with its N-terminus at the membrane, in contrast to extrasynaptic locations where it adopts a compact or open configurations of its N- and C-termini with parallel orientation to the membrane. In contrast, GFP-tagged AKAP79 CS was displaced from the PSD coincident with disruption of its vertical orientation, while proximity and orientation with respect to the extra-synaptic membrane was less impacted. Single-molecule localization microscopy (SMLM) revealed a heterogeneous distribution of AKAP150 with distinct high-density, nano-scale regions (HDRs) overlapping the PSD but more prominently located in the extrasynaptic membrane for WT and the CS mutant. Thick section scanning transmission electron microscopy (STEM) tomography revealed AKAP150 immunogold clusters similar in size to HDRs seen by SMLM and more AKAP150 labeled endosomes in spines for WT than for CS, consistent with the requirement for AKAP palmitoylation in endosomal trafficking. Hidden Markov modeling of single molecule tracking data revealed a bound/immobile fraction and two mobile fractions for AKAP79 in spines, with the CS mutant having shorter dwell times and faster transition rates between states than WT, suggesting that palmitoylation stabilizes individual AKAP molecules in various spine subpopulations. These data demonstrate that palmitoylation fine tunes the nanoscale localization, mobility, and trafficking of AKAP79/150 in dendritic spines, which might have profound effects on its regulation of synaptic plasticity.
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Affiliation(s)
- Xiaobing Chen
- Laboratory of Neurobiology, National Institute of Neurological Diseases and Stroke (NINDS), National Institutes of Health (NIH), Bethesda, MD, United States
- *Correspondence: Xiaobing Chen,
| | - Kevin C. Crosby
- Department of Pharmacology, University of Colorado School of Medicine, Anschutz Medical Campus, Aurora, CO, United States
| | - Austin Feng
- Laboratory of Neurobiology, National Institute of Neurological Diseases and Stroke (NINDS), National Institutes of Health (NIH), Bethesda, MD, United States
| | - Alicia M. Purkey
- Department of Pharmacology, University of Colorado School of Medicine, Anschutz Medical Campus, Aurora, CO, United States
| | - Maria A. Aronova
- Laboratory of Cellular Imaging and Macromolecular Biophysics, National Institute of Biomedical Imaging and Bioengineering (NIBIB), National Institutes of Health (NIH), Bethesda, MD, United States
| | - Christine A. Winters
- Laboratory of Neurobiology, National Institute of Neurological Diseases and Stroke (NINDS), National Institutes of Health (NIH), Bethesda, MD, United States
| | - Virginia T. Crocker
- Laboratory of Neurobiology, National Institute of Neurological Diseases and Stroke (NINDS), National Institutes of Health (NIH), Bethesda, MD, United States
| | - Richard D. Leapman
- Laboratory of Cellular Imaging and Macromolecular Biophysics, National Institute of Biomedical Imaging and Bioengineering (NIBIB), National Institutes of Health (NIH), Bethesda, MD, United States
| | - Thomas S. Reese
- Laboratory of Neurobiology, National Institute of Neurological Diseases and Stroke (NINDS), National Institutes of Health (NIH), Bethesda, MD, United States
| | - Mark L. Dell’Acqua
- Department of Pharmacology, University of Colorado School of Medicine, Anschutz Medical Campus, Aurora, CO, United States
- Mark L. Dell’Acqua,
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Sarkar D, Kang J, Wassie AT, Schroeder ME, Peng Z, Tarr TB, Tang AH, Niederst ED, Young JZ, Su H, Park D, Yin P, Tsai LH, Blanpied TA, Boyden ES. Revealing nanostructures in brain tissue via protein decrowding by iterative expansion microscopy. Nat Biomed Eng 2022; 6:1057-1073. [PMID: 36038771 PMCID: PMC9551354 DOI: 10.1038/s41551-022-00912-3] [Citation(s) in RCA: 27] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2020] [Accepted: 06/22/2022] [Indexed: 12/25/2022]
Abstract
Many crowded biomolecular structures in cells and tissues are inaccessible to labelling antibodies. To understand how proteins within these structures are arranged with nanoscale precision therefore requires that these structures be decrowded before labelling. Here we show that an iterative variant of expansion microscopy (the permeation of cells and tissues by a swellable hydrogel followed by isotropic hydrogel expansion, to allow for enhanced imaging resolution with ordinary microscopes) enables the imaging of nanostructures in expanded yet otherwise intact tissues at a resolution of about 20 nm. The method, which we named 'expansion revealing' and validated with DNA-probe-based super-resolution microscopy, involves gel-anchoring reagents and the embedding, expansion and re-embedding of the sample in homogeneous swellable hydrogels. Expansion revealing enabled us to use confocal microscopy to image the alignment of pre-synaptic calcium channels with post-synaptic scaffolding proteins in intact brain circuits, and to uncover periodic amyloid nanoclusters containing ion-channel proteins in brain tissue from a mouse model of Alzheimer's disease. Expansion revealing will enable the further discovery of previously unseen nanostructures within cells and tissues.
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Affiliation(s)
- Deblina Sarkar
- Media Lab, MIT, Cambridge, MA, 02139, USA.,MIT Center for Neurobiological Engineering, MIT, Cambridge, MA, 02139, USA.,These authors contributed equally
| | - Jinyoung Kang
- MIT McGovern Institute for Brain Research, MIT, Cambridge, MA, 02139, USA.,These authors contributed equally
| | - Asmamaw T Wassie
- Department of Biological Engineering, MIT, Cambridge, MA, 02139, USA.,These authors contributed equally
| | - Margaret E. Schroeder
- MIT McGovern Institute for Brain Research, MIT, Cambridge, MA, 02139, USA.,Department of Brain and Cognitive Sciences, MIT, Cambridge, MA, 02139, USA
| | - Zhuyu Peng
- Department of Brain and Cognitive Sciences, MIT, Cambridge, MA, 02139, USA.,The Picower Institute for Learning and Memory, MIT, Cambridge, MA, 02139, USA
| | - Tyler B. Tarr
- Department of Physiology, University of Maryland School of Medicine, Baltimore, MD, 21201, USA
| | - Ai-Hui Tang
- Department of Physiology, University of Maryland School of Medicine, Baltimore, MD, 21201, USA.,CAS Key Laboratory of Brain Function and Disease, Biomedical Sciences and Health Laboratory of Anhui Province, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, 230031, China
| | - Emily D. Niederst
- The Picower Institute for Learning and Memory, MIT, Cambridge, MA, 02139, USA
| | - Jennie, Z. Young
- Department of Brain and Cognitive Sciences, MIT, Cambridge, MA, 02139, USA.,The Picower Institute for Learning and Memory, MIT, Cambridge, MA, 02139, USA
| | - Hanquan Su
- Wyss Institute for Biologically Inspired Engineering, Harvard University, Boston, MA, 02115, USA.,Department of Systems Biology, Harvard Medical School, Boston, MA, 02115, USA
| | - Demian Park
- MIT McGovern Institute for Brain Research, MIT, Cambridge, MA, 02139, USA
| | - Peng Yin
- Wyss Institute for Biologically Inspired Engineering, Harvard University, Boston, MA, 02115, USA.,Department of Systems Biology, Harvard Medical School, Boston, MA, 02115, USA
| | - Li-Huei Tsai
- Department of Brain and Cognitive Sciences, MIT, Cambridge, MA, USA. .,The Picower Institute for Learning and Memory, MIT, Cambridge, MA, USA. .,Broad Institute of MIT and Harvard, Cambridge, MA, USA.
| | - Thomas A. Blanpied
- Department of Physiology, University of Maryland School of Medicine, Baltimore, MD, 21201, USA.,Program in Neuroscience, University of Maryland School of Medicine, Baltimore, MD, 21201, USA.,Correspondence and requests for materials should be addressed to Li-Huei Tsai, Thomas A. Blanpied or Edward S. Boyden. , ,
| | - Edward S. Boyden
- MIT Center for Neurobiological Engineering, MIT, Cambridge, MA, 02139, USA.,MIT McGovern Institute for Brain Research, MIT, Cambridge, MA, 02139, USA.,Department of Biological Engineering, MIT, Cambridge, MA, 02139, USA.,Department of Brain and Cognitive Sciences, MIT, Cambridge, MA, 02139, USA.,Koch Institute, MIT, Cambridge, MA, 02139, USA.,Howard Hughes Medical Institute, Cambridge, MA, 02139, USA.,Media Arts and Sciences, MIT, Cambridge, MA, 02139, USA.,K. Lisa Yang Center for Bionics, MIT, Cambridge, MA, 02139, USA.,Correspondence and requests for materials should be addressed to Li-Huei Tsai, Thomas A. Blanpied or Edward S. Boyden. , ,
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42
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Nozawa K, Sogabe T, Hayashi A, Motohashi J, Miura E, Arai I, Yuzaki M. In vivo nanoscopic landscape of neurexin ligands underlying anterograde synapse specification. Neuron 2022; 110:3168-3185.e8. [PMID: 36007521 DOI: 10.1016/j.neuron.2022.07.027] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2021] [Revised: 05/04/2022] [Accepted: 07/27/2022] [Indexed: 11/17/2022]
Abstract
Excitatory synapses are formed and matured by the cooperative actions of synaptic organizers, such as neurexins (Nrxns), neuroligins (Nlgns), LRRTMs, and Cbln1. Recent super-resolution nanoscopy developments have revealed that many synaptic organizers, as well as glutamate receptors and glutamate release machinery, exist as nanoclusters within synapses. However, it is unclear how such nanodomains interact with each other to organize excitatory synapses in vivo. By applying X10 expansion microscopy to epitope tag knockin mice, we found that Cbln1, Nlgn1, and LRRTM1, which share Nrxn as a common presynaptic receptor, form overlapping or separate nanodomains depending on Nrxn with or without a sequence encoded by splice site 4. The size and position of glutamate receptor nanodomains of GluD1, NMDA, and AMPA receptors were regulated by Cbln1, Nlgn1, and LRRTM1 nanodomains, respectively. These findings indicate that Nrxns anterogradely regulate the postsynaptic nanoscopic architecture of glutamate receptors through competition and coordination of Nrxn ligands.
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Affiliation(s)
- Kazuya Nozawa
- Department of Physiology, Keio University School of Medicine, Tokyo 160-8582, Japan
| | - Taku Sogabe
- Department of Physiology, Keio University School of Medicine, Tokyo 160-8582, Japan
| | - Ayumi Hayashi
- Department of Physiology, Keio University School of Medicine, Tokyo 160-8582, Japan
| | - Junko Motohashi
- Department of Physiology, Keio University School of Medicine, Tokyo 160-8582, Japan
| | - Eriko Miura
- Department of Physiology, Keio University School of Medicine, Tokyo 160-8582, Japan
| | - Itaru Arai
- Department of Physiology, Keio University School of Medicine, Tokyo 160-8582, Japan
| | - Michisuke Yuzaki
- Department of Physiology, Keio University School of Medicine, Tokyo 160-8582, Japan.
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43
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Viard J, Loe-Mie Y, Daudin R, Khelfaoui M, Plancon C, Boland A, Tejedor F, Huganir RL, Kim E, Kinoshita M, Liu G, Haucke V, Moncion T, Yu E, Hindie V, Bléhaut H, Mircher C, Herault Y, Deleuze JF, Rain JC, Simonneau M, Lepagnol-Bestel AM. Chr21 protein-protein interactions: enrichment in proteins involved in intellectual disability, autism, and late-onset Alzheimer's disease. Life Sci Alliance 2022; 5:e202101205. [PMID: 35914814 PMCID: PMC9348576 DOI: 10.26508/lsa.202101205] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2021] [Revised: 07/04/2022] [Accepted: 07/06/2022] [Indexed: 11/24/2022] Open
Abstract
Down syndrome (DS) is caused by human chromosome 21 (HSA21) trisomy. It is characterized by a poorly understood intellectual disability (ID). We studied two mouse models of DS, one with an extra copy of the <i>Dyrk1A</i> gene (189N3) and the other with an extra copy of the mouse Chr16 syntenic region (Dp(16)1Yey). RNA-seq analysis of the transcripts deregulated in the embryonic hippocampus revealed an enrichment in genes associated with chromatin for the 189N3 model, and synapses for the Dp(16)1Yey model. A large-scale yeast two-hybrid screen (82 different screens, including 72 HSA21 baits and 10 rebounds) of a human brain library containing at least 10<sup>7</sup> independent fragments identified 1,949 novel protein-protein interactions. The direct interactors of HSA21 baits and rebounds were significantly enriched in ID-related genes (<i>P</i>-value < 2.29 × 10<sup>-8</sup>). Proximity ligation assays showed that some of the proteins encoded by HSA21 were located at the dendritic spine postsynaptic density, in a protein network at the dendritic spine postsynapse. We located HSA21 DYRK1A and DSCAM, mutations of which increase the risk of autism spectrum disorder (ASD) 20-fold, in this postsynaptic network. We found that an intracellular domain of DSCAM bound either DLGs, which are multimeric scaffolds comprising receptors, ion channels and associated signaling proteins, or DYRK1A. The DYRK1A-DSCAM interaction domain is conserved in <i>Drosophila</i> and humans. The postsynaptic network was found to be enriched in proteins associated with ARC-related synaptic plasticity, ASD, and late-onset Alzheimer's disease. These results highlight links between DS and brain diseases with a complex genetic basis.
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Affiliation(s)
- Julia Viard
- Centre Psychiatrie and Neurosciences, INSERM U894, Paris, France
- Laboratoire de Génomique Fonctionnelle, CNG, Commissariat à l'Énergie Atomique et aux Énergies Alternatives (CEA), Evry, France
| | - Yann Loe-Mie
- Centre Psychiatrie and Neurosciences, INSERM U894, Paris, France
| | - Rachel Daudin
- Centre Psychiatrie and Neurosciences, INSERM U894, Paris, France
| | - Malik Khelfaoui
- Centre Psychiatrie and Neurosciences, INSERM U894, Paris, France
| | - Christine Plancon
- Laboratoire de Génomique Fonctionnelle, CNG, Commissariat à l'Énergie Atomique et aux Énergies Alternatives (CEA), Evry, France
| | - Anne Boland
- Laboratoire de Génomique Fonctionnelle, CNG, Commissariat à l'Énergie Atomique et aux Énergies Alternatives (CEA), Evry, France
| | - Francisco Tejedor
- Instituto de Neurociencias, Consejo Superior de Investigaciones Científicas-Universidad Miguel Hernández (CSIC-UMH), Universidad Miguel Hernandez-Campus de San Juan, San Juan, Spain
| | - Richard L Huganir
- Department of Neuroscience, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Eunjoon Kim
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology (KAIST), Center for Synaptic Brain Dysfunctions, Institute for Basic Science (IBS), Daejeon, Republic of Korea
| | - Makoto Kinoshita
- Department of Molecular Biology, Division of Biological Science, Nagoya University Graduate School of Science, Nagoya, Japan
| | - Guofa Liu
- Department of Biological Sciences, University of Toledo, Toledo, OH, USA
| | - Volker Haucke
- Department of Molecular Pharmacology and Cell Biology, Leibniz Institut für Molekulare Pharmakologie (FMP) and Freie Universität Berlin, Berlin, Germany
| | | | - Eugene Yu
- Department of Cellular and Molecular Biology, Roswell Park Division of Graduate School, State University of New York at Buffalo, Buffalo, NY, USA
| | | | | | | | - Yann Herault
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, Illkirch, France
- Centre National de la Recherche Scientifique (CNRS), UMR7104, Illkirch, France
- INSERM, U964, Illkirch, France
- Université de Strasbourg, Illkirch, France
- PHENOMIN, Institut Clinique de la Souris, ICS, GIE CERBM, CNRS, INSERM, Université de Strasbourg, Illkirch-Graffenstaden, France
| | - Jean-François Deleuze
- Laboratoire de Génomique Fonctionnelle, CNG, Commissariat à l'Énergie Atomique et aux Énergies Alternatives (CEA), Evry, France
| | | | - Michel Simonneau
- Centre Psychiatrie and Neurosciences, INSERM U894, Paris, France
- Université Paris-Saclay, CNRS, ENS Paris-Saclay, CentraleSupélec, LuMIn, Gif sur Yvette, France
- Department of Biology, Ecole Normale Supérieure Paris-Saclay Université Paris-Saclay, Gif sur Yvette, France
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44
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Voglewede MM, Zhang H. Polarity proteins: Shaping dendritic spines and memory. Dev Biol 2022; 488:68-73. [PMID: 35580729 PMCID: PMC9953585 DOI: 10.1016/j.ydbio.2022.05.007] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2021] [Revised: 05/09/2022] [Accepted: 05/10/2022] [Indexed: 02/01/2023]
Abstract
The morphogenesis and plasticity of dendritic spines are associated with synaptic strength, learning, and memory. Dendritic spines are highly compartmentalized structures, which makes proteins involved in cellular polarization and membrane compartmentalization likely candidates regulating their formation and maintenance. Indeed, recent studies suggest polarity proteins help form and maintain dendritic spines by compartmentalizing the spine neck and head. Here, we review emerging evidence that polarity proteins regulate dendritic spine plasticity and stability through the cytoskeleton, scaffolding molecules, and signaling molecules. We specifically analyze various polarity complexes known to contribute to different forms of cell polarization processes and examine the essential conceptual context linking these groups of polarity proteins to dendritic spine morphogenesis, plasticity, and cognitive functions.
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Affiliation(s)
| | - Huaye Zhang
- Department of Neuroscience and Cell Biology, Rutgers Robert Wood Johnson Medical School, Piscataway, NJ, 08854, USA.
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45
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Gormal RS, Meunier FA. Nanoscale organization of the pre-synapse: Tracking the neurotransmitter release machinery. Curr Opin Neurobiol 2022; 75:102576. [PMID: 35716557 DOI: 10.1016/j.conb.2022.102576] [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: 02/16/2022] [Revised: 05/02/2022] [Accepted: 05/11/2022] [Indexed: 11/18/2022]
Abstract
Chemical communication is underpinned by the fusion of neurotransmitter-containing synaptic vesicles with the plasma membrane at active zones. With the advent of super-resolution microscopy, the door is now opened to unravel the dynamic remodeling of synapses underpinning learning and memory. Imaging proteins with conventional light microscopy cannot provide submicron information vital to determining the nanoscale organization of the synapse. We will first review the current super-resolution microscopy techniques available to investigate the localization and movement of synaptic proteins and how they have been applied to visualize the synapse. We discuss the new techniques and analytical approaches have provided comprehensive insights into synaptic organization in various model systems. Finally, this review provides a brief update on how these super-resolution techniques and analyses have opened the way to a much greater understanding of the synapse, the fusion and compensatory endocytosis machinery.
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Affiliation(s)
- Rachel S Gormal
- Clem Jones Centre for Ageing Dementia Research, Queensland Brain Institute, The University of Queensland, Brisbane, Queensland, 4072, Australia. https://twitter.com/rachelgormal
| | - Frédéric A Meunier
- Clem Jones Centre for Ageing Dementia Research, Queensland Brain Institute, The University of Queensland, Brisbane, Queensland, 4072, Australia.
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46
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Chindemi G, Abdellah M, Amsalem O, Benavides-Piccione R, Delattre V, Doron M, Ecker A, Jaquier AT, King J, Kumbhar P, Monney C, Perin R, Rössert C, Tuncel AM, Van Geit W, DeFelipe J, Graupner M, Segev I, Markram H, Muller EB. A calcium-based plasticity model for predicting long-term potentiation and depression in the neocortex. Nat Commun 2022; 13:3038. [PMID: 35650191 PMCID: PMC9160074 DOI: 10.1038/s41467-022-30214-w] [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: 05/11/2021] [Accepted: 04/19/2022] [Indexed: 01/14/2023] Open
Abstract
Pyramidal cells (PCs) form the backbone of the layered structure of the neocortex, and plasticity of their synapses is thought to underlie learning in the brain. However, such long-term synaptic changes have been experimentally characterized between only a few types of PCs, posing a significant barrier for studying neocortical learning mechanisms. Here we introduce a model of synaptic plasticity based on data-constrained postsynaptic calcium dynamics, and show in a neocortical microcircuit model that a single parameter set is sufficient to unify the available experimental findings on long-term potentiation (LTP) and long-term depression (LTD) of PC connections. In particular, we find that the diverse plasticity outcomes across the different PC types can be explained by cell-type-specific synaptic physiology, cell morphology and innervation patterns, without requiring type-specific plasticity. Generalizing the model to in vivo extracellular calcium concentrations, we predict qualitatively different plasticity dynamics from those observed in vitro. This work provides a first comprehensive null model for LTP/LTD between neocortical PC types in vivo, and an open framework for further developing models of cortical synaptic plasticity.
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Affiliation(s)
- Giuseppe Chindemi
- Blue Brain Project, École Polytechnique Fédérale de Lausanne, Geneva, Switzerland.
| | - Marwan Abdellah
- Blue Brain Project, École Polytechnique Fédérale de Lausanne, Geneva, Switzerland
| | - Oren Amsalem
- Department of Neurobiology, the Hebrew University of Jerusalem, Jerusalem, Israel.,Division of Endocrinology, Diabetes and Metabolism, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, 02215, USA
| | - Ruth Benavides-Piccione
- Instituto Cajal, Consejo Superior de Investigaciones Científicas, Madrid, Spain.,Laboratorio Cajal de Circuitos Corticales, Centro de Tecnología Biomédica, Universidad Politécnica de Madrid, Madrid, Spain
| | - Vincent Delattre
- Laboratory of Neural Microcircuitry, École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | - Michael Doron
- Edmond and Lily Safra Center for Brain Sciences, the Hebrew University of Jerusalem, Jerusalem, Israel
| | - András Ecker
- Blue Brain Project, École Polytechnique Fédérale de Lausanne, Geneva, Switzerland
| | - Aurélien T Jaquier
- Blue Brain Project, École Polytechnique Fédérale de Lausanne, Geneva, Switzerland
| | - James King
- Blue Brain Project, École Polytechnique Fédérale de Lausanne, Geneva, Switzerland
| | - Pramod Kumbhar
- Blue Brain Project, École Polytechnique Fédérale de Lausanne, Geneva, Switzerland
| | - Caitlin Monney
- Blue Brain Project, École Polytechnique Fédérale de Lausanne, Geneva, Switzerland
| | - Rodrigo Perin
- Laboratory of Neural Microcircuitry, École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | - Christian Rössert
- Blue Brain Project, École Polytechnique Fédérale de Lausanne, Geneva, Switzerland
| | - Anil M Tuncel
- Blue Brain Project, École Polytechnique Fédérale de Lausanne, Geneva, Switzerland
| | - Werner Van Geit
- Blue Brain Project, École Polytechnique Fédérale de Lausanne, Geneva, Switzerland
| | - Javier DeFelipe
- Instituto Cajal, Consejo Superior de Investigaciones Científicas, Madrid, Spain.,Laboratorio Cajal de Circuitos Corticales, Centro de Tecnología Biomédica, Universidad Politécnica de Madrid, Madrid, Spain
| | - Michael Graupner
- Université de Paris, SPPIN - Saints-Pères Paris Institute for the Neurosciences, CNRS, Paris, France
| | - Idan Segev
- Department of Neurobiology, the Hebrew University of Jerusalem, Jerusalem, Israel.,Edmond and Lily Safra Center for Brain Sciences, the Hebrew University of Jerusalem, Jerusalem, Israel
| | - Henry Markram
- Blue Brain Project, École Polytechnique Fédérale de Lausanne, Geneva, Switzerland.,Laboratory of Neural Microcircuitry, École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | - Eilif B Muller
- Blue Brain Project, École Polytechnique Fédérale de Lausanne, Geneva, Switzerland. .,Department of Neurosciences, Faculty of Medicine, Université de Montréal, Montréal, QC, Canada. .,CHU Sainte-Justine Research Center, Montréal, QC, Canada. .,Quebec Artificial Intelligence Institute (Mila), Montréal, Canada.
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47
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Sun SY, Li XW, Cao R, Zhao Y, Sheng N, Tang AH. Correlative Assembly of Subsynaptic Nanoscale Organizations During Development. Front Synaptic Neurosci 2022; 14:748184. [PMID: 35685244 PMCID: PMC9171000 DOI: 10.3389/fnsyn.2022.748184] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2021] [Accepted: 03/11/2022] [Indexed: 11/17/2022] Open
Abstract
Nanoscale organization of presynaptic proteins determines the sites of transmitter release, and its alignment with assemblies of postsynaptic receptors through nanocolumns is suggested to optimize the efficiency of synaptic transmission. However, it remains unknown how these nano-organizations are formed during development. In this study, we used super-resolution stochastic optical reconstruction microscopy (STORM) imaging technique to systematically analyze the evolvement of subsynaptic organization of three key synaptic proteins, namely, RIM1/2, GluA1, and PSD-95, during synapse maturation in cultured hippocampal neurons. We found that volumes of synaptic clusters and their subsynaptic heterogeneity increase as synapses get matured. Synapse sizes of presynaptic and postsynaptic compartments correlated well at all stages, while only more mature synapses demonstrated a significant correlation between presynaptic and postsynaptic nano-organizations. After a long incubation with an inhibitor of action potentials or AMPA receptors, both presynaptic and postsynaptic compartments showed increased synaptic cluster volume and subsynaptic heterogeneity; however, the trans-synaptic alignment was intact. Together, our results characterize the evolvement of subsynaptic protein architectures during development and demonstrate that the nanocolumn is organized more likely by an intrinsic mechanism and independent of synaptic activities.
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Affiliation(s)
- Shi-Yan Sun
- Chinese Academy of Sciences (CAS) Key Laboratory of Brain Function and Disease, Ministry of Education Key Laboratory for Membrane-less Organelles and Cellular Dynamics, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, China
- Institute of Artificial Intelligence, Hefei Comprehensive National Science Center, Hefei, China
| | - Xiao-Wei Li
- Chinese Academy of Sciences (CAS) Key Laboratory of Brain Function and Disease, Ministry of Education Key Laboratory for Membrane-less Organelles and Cellular Dynamics, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, China
| | - Ran Cao
- Chinese Academy of Sciences (CAS) Key Laboratory of Brain Function and Disease, Ministry of Education Key Laboratory for Membrane-less Organelles and Cellular Dynamics, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, China
| | - Yang Zhao
- Chinese Academy of Sciences (CAS) Key Laboratory of Brain Function and Disease, Ministry of Education Key Laboratory for Membrane-less Organelles and Cellular Dynamics, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, China
- State Key Laboratory of Genetic Resources and Evolution in Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, China
| | - Nengyin Sheng
- State Key Laboratory of Genetic Resources and Evolution in Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, China
- Nengyin Sheng
| | - Ai-Hui Tang
- Chinese Academy of Sciences (CAS) Key Laboratory of Brain Function and Disease, Ministry of Education Key Laboratory for Membrane-less Organelles and Cellular Dynamics, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, China
- Institute of Artificial Intelligence, Hefei Comprehensive National Science Center, Hefei, China
- *Correspondence: Ai-Hui Tang
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48
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Toledo A, Letellier M, Bimbi G, Tessier B, Daburon S, Favereaux A, Chamma I, Vennekens K, Vanderlinden J, Sainlos M, de Wit J, Choquet D, Thoumine O. MDGAs are fast-diffusing molecules that delay excitatory synapse development by altering neuroligin behavior. eLife 2022; 11:75233. [PMID: 35532105 PMCID: PMC9084894 DOI: 10.7554/elife.75233] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2021] [Accepted: 04/11/2022] [Indexed: 12/28/2022] Open
Abstract
MDGA molecules can bind neuroligins and interfere with trans-synaptic interactions to neurexins, thereby impairing synapse development. However, the subcellular localization and dynamics of MDGAs, or their specific action mode in neurons remain unclear. Here, surface immunostaining of endogenous MDGAs and single molecule tracking of recombinant MDGAs in dissociated hippocampal neurons reveal that MDGAs are homogeneously distributed and exhibit fast membrane diffusion, with a small reduction in mobility across neuronal maturation. Knocking-down/out MDGAs using shRNAs and CRISPR/Cas9 strategies increases the density of excitatory synapses, the membrane confinement of neuroligin-1, and the phosphotyrosine level of neuroligins associated with excitatory post-synaptic differentiation. Finally, MDGA silencing reduces the mobility of AMPA receptors, increases the frequency of miniature EPSCs (but not IPSCs), and selectively enhances evoked AMPA-receptor-mediated EPSCs in CA1 pyramidal neurons. Overall, our results support a mechanism by which interactions between MDGAs and neuroligin-1 delays the assembly of functional excitatory synapses containing AMPA receptors.
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Affiliation(s)
- Andrea Toledo
- University of Bordeaux, CNRS UMR 5297, Interdisciplinary Institute for Neuroscience
| | - Mathieu Letellier
- University of Bordeaux, CNRS UMR 5297, Interdisciplinary Institute for Neuroscience
| | - Giorgia Bimbi
- University of Bordeaux, CNRS UMR 5297, Interdisciplinary Institute for Neuroscience
| | - Béatrice Tessier
- University of Bordeaux, CNRS UMR 5297, Interdisciplinary Institute for Neuroscience
| | - Sophie Daburon
- University of Bordeaux, CNRS UMR 5297, Interdisciplinary Institute for Neuroscience
| | - Alexandre Favereaux
- University of Bordeaux, CNRS UMR 5297, Interdisciplinary Institute for Neuroscience
| | - Ingrid Chamma
- University of Bordeaux, CNRS UMR 5297, Interdisciplinary Institute for Neuroscience
| | - Kristel Vennekens
- VIB Center for Brain & Disease Research and KU Leuven, Department of Neurosciences, Leuven Brain Institute
| | - Jeroen Vanderlinden
- VIB Center for Brain & Disease Research and KU Leuven, Department of Neurosciences, Leuven Brain Institute
| | - Matthieu Sainlos
- University of Bordeaux, CNRS UMR 5297, Interdisciplinary Institute for Neuroscience
| | - Joris de Wit
- VIB Center for Brain & Disease Research and KU Leuven, Department of Neurosciences, Leuven Brain Institute
| | - Daniel Choquet
- University of Bordeaux, CNRS UMR 5297, Interdisciplinary Institute for Neuroscience
- University of Bordeaux, CNRS UAR 3420, INSERM, Bordeaux Imaging Center
| | - Olivier Thoumine
- University of Bordeaux, CNRS UMR 5297, Interdisciplinary Institute for Neuroscience
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49
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Choquet D, Opazo P. The role of AMPAR lateral diffusion in memory. Semin Cell Dev Biol 2022; 125:76-83. [PMID: 35123863 DOI: 10.1016/j.semcdb.2022.01.009] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2021] [Revised: 01/26/2022] [Accepted: 01/27/2022] [Indexed: 12/17/2022]
Abstract
The accumulation of AMPARs to synapses is a fundamental step in Long-term potentiation (LTP) of synaptic transmission, a well-established cellular correlate of learning and memory. The discovery of a sizeable and highly mobile population of extrasynaptic AMPARs - randomly scanning the synaptic surface under basal conditions - provided a conceptual framework for a simplified model: LTP can be induced by the capture, and hence accumulation, of laterally diffusing extrasynaptic AMPARs. Here, we review the evidence supporting a rate-limiting role of AMPAR lateral diffusion in LTP and as consequence, in learning and memory. We propose that there are "multiple solutions" for achieving the diffusional trapping of AMPAR during LTP, mainly mediated by the interaction between interchangeable AMPAR auxiliary subunits and cell-adhesion molecules containing PDZ-binding domains and synaptic scaffolds containing PDZ-domains. We believe that this molecular degeneracy in the diffusional trapping of AMPAR during LTP serve to ensure the robustness of this crucial step in the making of memories. All in all, the role of AMPAR lateral diffusion in LTP is not only a conceptual leap in our understanding of memory, but it might also hold the keys for the development of therapeutics against disorders associated with memory deficits such as Alzheimer's disease.
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Affiliation(s)
- Daniel Choquet
- Interdisciplinary Institute for Neuroscience, CNRS, Univ. Bordeaux, IINS, UMR 5297, Bordeaux, France; Univ. Bordeaux, CNRS, INSERM, Bordeaux Imaging Center, BIC, UMS 3420, Bordeaux, France.
| | - Patricio Opazo
- UK Dementia Research Institute, Centre for Discovery Brain Sciences, University of Edinburgh, Chancellor's Building, Edinburgh Medical School, Edinburgh EH16 4SB, UK; Clem Jones Centre for Ageing Dementia Research, Queensland Brain Institute, The University of Queensland, Brisbane, QLD 4072, Australia.
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50
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Feng Y, Brunel N. Storage capacity of networks with discrete synapses and sparsely encoded memories. Phys Rev E 2022; 105:054408. [PMID: 35706193 DOI: 10.1103/physreve.105.054408] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2021] [Accepted: 03/11/2022] [Indexed: 06/15/2023]
Abstract
Attractor neural networks are one of the leading theoretical frameworks for the formation and retrieval of memories in networks of biological neurons. In this framework, a pattern imposed by external inputs to the network is said to be learned when this pattern becomes a fixed point attractor of the network dynamics. The storage capacity is the maximum number of patterns that can be learned by the network. In this paper, we study the storage capacity of fully connected and sparsely connected networks with a binarized Hebbian rule, for arbitrary coding levels. Our results show that a network with discrete synapses has a similar storage capacity as the model with continuous synapses, and that this capacity tends asymptotically towards the optimal capacity, in the space of all possible binary connectivity matrices, in the sparse coding limit. We also derive finite coding level corrections for the asymptotic solution in the sparse coding limit. The result indicates the capacity of networks with Hebbian learning rules converges to the optimal capacity extremely slowly when the coding level becomes small. Our results also show that in networks with sparse binary connectivity matrices, the information capacity per synapse is larger than in the fully connected case, and thus such networks store information more efficiently.
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Affiliation(s)
- Yu Feng
- Department of Physics, Duke University, Durham, North Carolina 27710, USA
| | - Nicolas Brunel
- Department of Physics, Duke University, Durham, North Carolina 27710, USA
- Department of Neurobiology, Duke University, Durham, North Carolina 27710, USA
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