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Schmidt CC, Tong R, Emptage NJ. GluN2A- and GluN2B-containing pre-synaptic N-methyl-d-aspartate receptors differentially regulate action potential-evoked Ca 2+ influx via modulation of SK channels. Philos Trans R Soc Lond B Biol Sci 2024; 379:20230222. [PMID: 38853550 DOI: 10.1098/rstb.2023.0222] [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: 09/29/2023] [Accepted: 01/02/2024] [Indexed: 06/11/2024] Open
Abstract
N-methyl-d-aspartate receptors (NMDARs) play a pivotal role in synaptic plasticity. While the functional role of post-synaptic NMDARs is well established, pre-synaptic NMDAR (pre-NMDAR) function is largely unexplored. Different pre-NMDAR subunit populations are documented at synapses, suggesting that subunit composition influences neuronal transmission. Here, we used electrophysiological recordings at Schaffer collateral-CA1 synapses partnered with Ca2+ imaging and glutamate uncaging at boutons of CA3 pyramidal neurones to reveal two populations of pre-NMDARs that contain either the GluN2A or GluN2B subunit. Activation of the GluN2B population decreases action potential-evoked Ca2+ influx via modulation of small-conductance Ca2+-activated K+ channels, while activation of the GluN2A population does the opposite. Critically, the level of functional expression of the subunits is subject to homeostatic regulation, bidirectionally affecting short-term facilitation, thus providing a capacity for a fine adjustment of information transfer. This article is part of a discussion meeting issue 'Long-term potentiation: 50 years on'.
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Affiliation(s)
- Carla C Schmidt
- Department of Pharmacology, University of Oxford , Oxford OX1 3QT, UK
| | - Rudi Tong
- Department of Pharmacology, University of Oxford , Oxford OX1 3QT, UK
- Montreal Neurological Institute, 3801 University Street , Montreal, Quebec H3A 2B4, Canada
| | - Nigel J Emptage
- Department of Pharmacology, University of Oxford , Oxford OX1 3QT, UK
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2
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Kim YD, Park HG, Song S, Kim J, Lee BJ, Broadie K, Lee S. Presynaptic structural and functional plasticity are coupled by convergent Rap1 signaling. J Cell Biol 2024; 223:e202309095. [PMID: 38748250 PMCID: PMC11096849 DOI: 10.1083/jcb.202309095] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2023] [Revised: 02/07/2024] [Accepted: 03/27/2024] [Indexed: 05/18/2024] Open
Abstract
Dynamic presynaptic actin remodeling drives structural and functional plasticity at synapses, but the underlying mechanisms remain largely unknown. Previous work has shown that actin regulation via Rac1 guanine exchange factor (GEF) Vav signaling restrains synaptic growth via bone morphogenetic protein (BMP)-induced receptor macropinocytosis and mediates synaptic potentiation via mobilization of reserve pool vesicles in presynaptic boutons. Here, we find that Gef26/PDZ-GEF and small GTPase Rap1 signaling couples the BMP-induced activation of Abelson kinase to this Vav-mediated macropinocytosis. Moreover, we find that adenylate cyclase Rutabaga (Rut) signaling via exchange protein activated by cAMP (Epac) drives the mobilization of reserve pool vesicles during post-tetanic potentiation (PTP). We discover that Rap1 couples activation of Rut-cAMP-Epac signaling to Vav-mediated synaptic potentiation. These findings indicate that Rap1 acts as an essential, convergent node for Abelson kinase and cAMP signaling to mediate BMP-induced structural plasticity and activity-induced functional plasticity via Vav-dependent regulation of the presynaptic actin cytoskeleton.
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Affiliation(s)
- Yeongjin David Kim
- Department of Brain and Cognitive Sciences, Seoul National University, Seoul, Korea
| | - Hyun Gwan Park
- Department of Brain and Cognitive Sciences, Seoul National University, Seoul, Korea
| | - Seunghwan Song
- Interdisciplinary Program in Neuroscience, Seoul National University, Seoul, Korea
| | - Joohyung Kim
- Department of Cell and Developmental Biology and Dental Research Institute, Seoul National University, Seoul, Korea
| | - Byoung Ju Lee
- Department of Cell and Developmental Biology and Dental Research Institute, Seoul National University, Seoul, Korea
| | - Kendal Broadie
- Departments of Cell and Developmental Biology, Pharmacology, and Biological Sciences, Vanderbilt University and Medical Center, Nashville, TN, USA
| | - Seungbok Lee
- Department of Brain and Cognitive Sciences, Seoul National University, Seoul, Korea
- Interdisciplinary Program in Neuroscience, Seoul National University, Seoul, Korea
- Department of Cell and Developmental Biology and Dental Research Institute, Seoul National University, Seoul, Korea
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3
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Zhang FL, Yang XK, Qi YT, Tian SY, Huang WH. Nanoelectrochemistry reveals how presynaptic neurons regulate vesicle release to sustain synaptic plasticity under repetitive stimuli. Chem Sci 2024; 15:7651-7658. [PMID: 38784745 PMCID: PMC11110134 DOI: 10.1039/d4sc01664e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2024] [Accepted: 04/12/2024] [Indexed: 05/25/2024] Open
Abstract
Synaptic plasticity is the ability of synapses to modulate synaptic strength in response to dynamic changes within, as well as environmental changes. Although there is a considerable body of knowledge on protein expression and receptor migration in different categories of synaptic plasticity, the contribution and impact of presynaptic vesicle release and neurotransmitter levels towards plasticity remain largely unclear. Herein, nanoelectrochemistry using carbon fiber nanoelectrodes with excellent spatio-temporal resolution was applied for real-time monitoring of presynaptic vesicle release of dopamine inside single synapses of dopaminergic neurons, and exocytotic variations in quantity and kinetics under repetitive electrical stimuli. We found that the presynaptic terminal tends to maintain synaptic strength by rapidly recruiting vesicles, changing the dynamics of exocytosis, and maintaining sufficient neurotransmitter release in following stimuli. Except for small clear synaptic vesicles, dense core vesicles are involved in exocytosis to sustain the neurotransmitter level in later periods of repetitive stimuli. These data indicate that vesicles use a potential regulatory mechanism to establish short-term plasticity, and provide new directions for exploring the synaptic mechanisms in connection and plasticity.
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Affiliation(s)
- Fu-Li Zhang
- College of Chemistry and Molecular Sciences, Wuhan University Wuhan 430072 P. R. China
| | - Xiao-Ke Yang
- College of Chemistry and Molecular Sciences, Wuhan University Wuhan 430072 P. R. China
| | - Yu-Ting Qi
- College of Chemistry and Molecular Sciences, Wuhan University Wuhan 430072 P. R. China
| | - Si-Yu Tian
- College of Chemistry and Molecular Sciences, Wuhan University Wuhan 430072 P. R. China
| | - Wei-Hua Huang
- College of Chemistry and Molecular Sciences, Wuhan University Wuhan 430072 P. R. China
- Department of Hepatobiliary and Pancreatic Surgery, Zhongnan Hospital of Wuhan University Wuhan 430071 P. R. China
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4
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Ma X, Wang X, Zhu K, Ma R, Chu F, Liu X, Zhang S, Yin T, Zhou X, Liu Z. Study on the Role of Physical Fields in TMAS to Modulate Synaptic Plasticity in Mice. IEEE Trans Biomed Eng 2024; 71:1531-1541. [PMID: 38117631 DOI: 10.1109/tbme.2023.3342012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2023]
Abstract
OBJECTIVE Transcranial magneto-acoustic stimulation (TMAS) is a composite technique combining static magnetic and coupled electric fields with transcranial ultrasound stimulation (TUS) and has shown advantages in neuromodulation. However, the role of these physical fields in neuromodulation is unclear. Synaptic plasticity is the cellular basis for learning and memory. In this paper, we varied the intensity of static magnetic, electric and ultrasonic fields respectively to investigate the modulation of synaptic plasticity by these physical fields. METHODS There are control, static magnetic field (0.1 T/0.2 T), TUS (0.15/0.3 MPa), and TMAS (0.15 MPa + 0.2 V/m, 0.3 MPa + 0.2 V/m, 0.3 MPa + 0.4 V/m) groups. Hippocampal areas were stimulated at 5 min daily for 7 days and in vivo electrophysiological experiments were performed. RESULTS TMAS induced greater LTP, LTD, and paired-pulse ratio (PPR) than TUS, reflecting that TMAS has a more significant modulation in both long- and short- term synaptic plasticity. In TMAS, a doubling of the electric field amplitude increases LTP, LTD and PPR to a greater extent than a doubling of the acoustic pressure. Increasing the static magnetic field intensity has no significant effect on the modulation of synaptic plasticity. CONCLUSION This paper argues that electric fields should be the main reason for the difference in modulation between TMAS and TUS and that changing the amplitude of the electric field affected the modulation of TMAS more than changing the acoustic pressure. SIGNIFICANCE This study elucidates the roles of the physical fields in TMAS and provides a parameterisation way to guide TMAS applications based on the dominant roles of the physical fields.
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Bose D, Bera M, Norman CA, Timofeeva Y, Volynski KE, Krishnakumar SS. A minimal presynaptic protein machinery mediating synchronous and asynchronous exocytosis and short-term plasticity. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.04.15.589559. [PMID: 38659918 PMCID: PMC11042279 DOI: 10.1101/2024.04.15.589559] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/26/2024]
Abstract
Neurotransmitters are released from synaptic vesicles with remarkable precision in response to presynaptic Ca2+ influx but exhibit significant heterogeneity in exocytosis timing and efficacy based on the recent history of activity. This heterogeneity is critical for information transfer in the brain, yet its molecular basis remains poorly understood. Here, we employ a biochemically-defined fusion assay under physiologically-relevant conditions to delineate the minimal protein machinery sufficient to account for different modes of Ca2+-triggered vesicle fusion and short-term facilitation. We find that Synaptotagmin-1, Synaptotagmin-7, and Complexin, synergistically restrain SNARE complex assembly, thus preserving vesicles in a stably docked state at rest. Upon Ca2+ activation, Synaptotagmin-1 induces rapid vesicle fusion, while Synaptotagmin-7 mediates delayed fusion. Competitive binding of Synaptotagmin-1 and Synaptotagmin-7 to the same SNAREs, coupled with differential rates of Ca2+-triggered fusion clamp reversal, govern the kinetics of vesicular fusion. Under conditions mimicking sustained neuronal activity, the Synaptotagmin-7 fusion clamp is destabilized by the elevated basal Ca2+ concentration, thereby enhancing the synchronous component of fusion. These findings provide a direct demonstration that a small set of proteins is sufficient to account for how nerve terminals adapt and regulate the Ca2+-evoked neurotransmitter exocytosis process to support their specialized functions in the nervous system.
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Affiliation(s)
- Dipayan Bose
- Yale Nanobiology Institute, Yale University School of Medicine, New Haven, USA
- Department of Neurology, Yale University School of Medicine, New Haven, USA
| | - Manindra Bera
- Yale Nanobiology Institute, Yale University School of Medicine, New Haven, USA
- Cell Biology, Yale University School of Medicine, New Haven, USA
| | - Chris A Norman
- Department of Clinical and Experimental Epilepsy, UCL Queen Square Institute of Neurology, University College London, UK
- Department of Computer Science, University of Warwick, Coventry, UK
| | - Yulia Timofeeva
- Department of Computer Science, University of Warwick, Coventry, UK
| | - Kirill E Volynski
- Cell Biology, Yale University School of Medicine, New Haven, USA
- Department of Clinical and Experimental Epilepsy, UCL Queen Square Institute of Neurology, University College London, UK
| | - Shyam S Krishnakumar
- Yale Nanobiology Institute, Yale University School of Medicine, New Haven, USA
- Department of Neurology, Yale University School of Medicine, New Haven, USA
- Department of Clinical and Experimental Epilepsy, UCL Queen Square Institute of Neurology, University College London, UK
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6
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Brown KA, Gould TD. Targeting metaplasticity mechanisms to promote sustained antidepressant actions. Mol Psychiatry 2024; 29:1114-1127. [PMID: 38177353 PMCID: PMC11176041 DOI: 10.1038/s41380-023-02397-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/22/2023] [Revised: 12/20/2023] [Accepted: 12/21/2023] [Indexed: 01/06/2024]
Abstract
The discovery that subanesthetic doses of (R, S)-ketamine (ketamine) and (S)-ketamine (esketamine) rapidly induce antidepressant effects and promote sustained actions following drug clearance in depressed patients who are treatment-resistant to other therapies has resulted in a paradigm shift in the conceptualization of how rapidly and effectively depression can be treated. Consequently, the mechanism(s) that next generation antidepressants may engage to improve pathophysiology and resultant symptomology are being reconceptualized. Impaired excitatory glutamatergic synapses in mood-regulating circuits are likely a substantial contributor to the pathophysiology of depression. Metaplasticity is the process of regulating future capacity for plasticity by priming neurons with a stimulation that alters later neuronal plasticity responses. Accordingly, the development of treatment modalities that specifically modulate the duration, direction, or magnitude of glutamatergic synaptic plasticity events such as long-term potentiation (LTP), defined here as metaplastogens, may be an effective approach to reverse the pathophysiology underlying depression and improve depression symptoms. We review evidence that the initiating mechanisms of pharmacologically diverse rapid-acting antidepressants (i.e., ketamine mimetics) converge on consistent downstream molecular mediators that facilitate the expression/maintenance of increased synaptic strength and resultant persisting antidepressant effects. Specifically, while the initiating mechanisms of these therapies may differ (e.g., cell type-specificity, N-methyl-D-aspartate receptor (NMDAR) subtype-selective inhibition vs activation, metabotropic glutamate receptor 2/3 antagonism, AMPA receptor potentiation, 5-HT receptor-activating psychedelics, etc.), the sustained therapeutic mechanisms of putative rapid-acting antidepressants will be mediated, in part, by metaplastic effects that converge on consistent molecular mediators to enhance excitatory neurotransmission and altered capacity for synaptic plasticity. We conclude that the convergence of these therapeutic mechanisms provides the opportunity for metaplasticity processes to be harnessed as a druggable plasticity mechanism by next-generation therapeutics. Further, targeting metaplastic mechanisms presents therapeutic advantages including decreased dosing frequency and associated diminished adverse responses by eliminating the requirement for the drug to be continuously present.
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Affiliation(s)
- Kyle A Brown
- Department of Psychiatry, University of Maryland School of Medicine, Baltimore, MD, 21201, USA
| | - Todd D Gould
- Department of Psychiatry, University of Maryland School of Medicine, Baltimore, MD, 21201, USA.
- Department of Pharmacology, University of Maryland School of Medicine, Baltimore, MD, 21201, USA.
- Department of Neurobiology, University of Maryland School of Medicine, Baltimore, MD, 21201, USA.
- Veterans Affairs Maryland Health Care System, Baltimore, MD, 21201, USA.
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7
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Kim J, Bustamante E, Sotonyi P, Maxwell ND, Parameswaran P, Kent JK, Wetsel WC, Soderblom EJ, Rácz B, Soderling SH. Presynaptic Rac1 in the hippocampus selectively regulates working memory. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.03.18.585488. [PMID: 38562715 PMCID: PMC10983896 DOI: 10.1101/2024.03.18.585488] [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
One of the most extensively studied members of the Ras superfamily of small GTPases, Rac1 is an intracellular signal transducer that remodels actin and phosphorylation signaling networks. Previous studies have shown that Rac1-mediated signaling is associated with hippocampal-dependent working memory and longer-term forms of learning and memory and that Rac1 can modulate forms of both pre- and postsynaptic plasticity. How these different cognitive functions and forms of plasticity mediated by Rac1 are linked, however, is unclear. Here, we show that spatial working memory is selectively impaired following the expression of a genetically encoded Rac1-inhibitor at presynaptic terminals, while longer-term cognitive processes are affected by Rac1 inhibition at postsynaptic sites. To investigate the regulatory mechanisms of this presynaptic process, we leveraged new advances in mass spectrometry to identify the proteomic and post-translational landscape of presynaptic Rac1 signaling. We identified serine/threonine kinases and phosphorylated cytoskeletal signaling and synaptic vesicle proteins enriched with active Rac1. The phosphorylated sites in these proteins are at positions likely to have regulatory effects on synaptic vesicles. Consistent with this, we also report changes in the distribution and morphology of synaptic vesicles and in postsynaptic ultrastructure following presynaptic Rac1 inhibition. Overall, this study reveals a previously unrecognized presynaptic role of Rac1 signaling in cognitive processes and provides insights into its potential regulatory mechanisms.
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Affiliation(s)
- Jaebin Kim
- Department of Cell Biology, Duke University Medical School, Durham, North Carolina, USA
| | - Edwin Bustamante
- Department of Cell Biology, Duke University Medical School, Durham, North Carolina, USA
| | - Peter Sotonyi
- Department of Anatomy and Histology, University of Veterinary Medicine, Budapest, Hungary
| | - Nicholas D Maxwell
- Department of Cell Biology, Duke University Medical School, Durham, North Carolina, USA
| | - Pooja Parameswaran
- Department of Cell Biology, Duke University Medical School, Durham, North Carolina, USA
| | - Julie K Kent
- Department of Cell Biology, Duke University Medical School, Durham, North Carolina, USA
| | - William C Wetsel
- Department of Cell Biology, Duke University Medical School, Durham, North Carolina, USA
- Mouse Behavioral and Neuroendocrine Analysis Core Facility, Duke University Medical School, Durham, North Carolina, USA
- Department of Neurobiology, Duke University Medical School, Durham, North Carolina, USA
| | - Erik J Soderblom
- Department of Cell Biology, Duke University Medical School, Durham, North Carolina, USA
- Mouse Behavioral and Neuroendocrine Analysis Core Facility, Duke University Medical School, Durham, North Carolina, USA
| | - Bence Rácz
- Department of Anatomy and Histology, University of Veterinary Medicine, Budapest, Hungary
| | - Scott H Soderling
- Department of Cell Biology, Duke University Medical School, Durham, North Carolina, USA
- Department of Neurobiology, Duke University Medical School, Durham, North Carolina, USA
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8
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Kang CJ, Guzmán-Clavel LE, Lei K, Koo M, To S, Roche JP. The exocyst subunit Sec15 is critical for proper synaptic development and function at the Drosophila NMJ. Mol Cell Neurosci 2024; 128:103914. [PMID: 38086519 DOI: 10.1016/j.mcn.2023.103914] [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: 08/25/2023] [Revised: 12/04/2023] [Accepted: 12/05/2023] [Indexed: 12/18/2023] Open
Abstract
The exocyst protein complex is important for targeted vesicle fusion in a variety of cell types, however, its function in neurons is still not entirely known. We found that presynaptic knockdown (KD) of the exocyst component sec15 by transgenic RNAi expression caused a number of unexpected morphological and physiological defects in the synapse. These include the development of active zones (AZ) devoid of essential presynaptic proteins, an increase in the branching of the presynaptic arbor, the appearance of satellite boutons, and a decrease in the amplitude of stimulated postsynaptic currents as well as a decrease in the frequency of spontaneous synaptic vesicle release. We also found the release of extracellular vesicles from the presynaptic neuron was greatly diminished in the Sec15 KDs. These effects were mimicked by presynaptic knockdown of Rab11, a protein known to interact with the exocyst. sec15 RNAi expression caused an increase in phosphorylated Mothers against decapentaplegic (pMad) in the presynaptic terminal, an indication of enhanced bone morphogenic protein (BMP) signaling. Some morphological phenotypes caused by Sec15 knockdown were reduced by attenuation of BMP signaling through knockdown of wishful thinking (Wit), while other phenotypes were unaffected. Individual knockdown of multiple proteins of the exocyst complex also displayed a morphological phenotype similar to Sec15 KD. We conclude that Sec15, functioning as part of the exocyst complex, is critically important for proper formation and function of neuronal synapses. We propose a model in which Sec15 is involved in the trafficking of vesicles from the recycling endosome to the cell membrane as well as possibly trafficking extracellular vesicles for presynaptic release and these processes are necessary for the correct structure and function of the synapse.
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Affiliation(s)
- Chris J Kang
- Neuroscience Program, Amherst College, Amherst, MA 01002, United States of America
| | - Luis E Guzmán-Clavel
- Neuroscience Program, Amherst College, Amherst, MA 01002, United States of America
| | - Katherine Lei
- Neuroscience Program, Amherst College, Amherst, MA 01002, United States of America
| | - Martin Koo
- Neuroscience Program, Amherst College, Amherst, MA 01002, United States of America
| | - Steven To
- Neuroscience Program, Amherst College, Amherst, MA 01002, United States of America
| | - John P Roche
- Neuroscience Program, Amherst College, Amherst, MA 01002, United States of America; Department of Biology, Amherst College, Amherst, MA 01002, United States of America.
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9
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Francis-Oliveira J, Higa GSV, Viana FJC, Cruvinel E, Carlos-Lima E, da Silva Borges F, Zampieri TT, Rebello FP, Ulrich H, De Pasquale R. TREK-1 inhibition promotes synaptic plasticity in the prelimbic cortex. Exp Neurol 2024; 373:114652. [PMID: 38103709 DOI: 10.1016/j.expneurol.2023.114652] [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: 10/06/2023] [Revised: 11/28/2023] [Accepted: 12/10/2023] [Indexed: 12/19/2023]
Abstract
Synaptic plasticity is one of the putative mechanisms involved in the maturation of the prefrontal cortex (PFC) during postnatal development. Early life stress (ELS) affects the shaping of cortical circuitries through impairment of synaptic plasticity supporting the onset of mood disorders. Growing evidence suggests that dysfunctional postnatal maturation of the prelimbic division (PL) of the PFC might be related to the emergence of depression. The potassium channel TREK-1 has attracted particular interest among many factors that modulate plasticity, concerning synaptic modifications that could underlie mood disorders. Studies have found that ablation of TREK-1 increases the resilience to depression, while rats exposed to ELS exhibit higher TREK-1 levels in the PL. TREK-1 is regulated by multiple intracellular transduction pathways including the ones activated by metabotropic receptors. In the hippocampal neurons, TREK-1 interacts with the serotonergic system, one of the main factors involved in the action of antidepressants. To investigate possible mechanisms related to the antidepressant role of TREK-1, we used brain slice electrophysiology to evaluate the effects of TREK-1 pharmacological blockade on synaptic plasticity at PL circuitry. We extended this investigation to animals subjected to ELS. Our findings suggest that in non-stressed animals, TREK-1 activity is required for the reduction of synaptic responses mediated by the 5HT1A receptor activation. Furthermore, we demonstrate that TREK-1 blockade promotes activity-dependent long-term depression (LTD) when acting in synergy with 5HT1A receptor stimulation. On the other hand, in ELS animals, TREK-1 blockade reduces synaptic transmission and facilitates LTD expression. These results indicate that TREK-1 inhibition stimulates synaptic plasticity in the PL and this effect is more pronounced in animals subjected to ELS during postnatal development.
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Affiliation(s)
- José Francis-Oliveira
- Laboratório de Neurofisiologia, Departamento de Fisiologia e Biofísica, Universidade de São Paulo, Butantã, SP 05508-000, Brazil; Department of Psychiatry and Behavioral Neurobiology, University of Alabama at Birmingham, Birmingham, AL 35233, USA
| | - Guilherme Shigueto Vilar Higa
- Laboratório de Neurofisiologia, Departamento de Fisiologia e Biofísica, Universidade de São Paulo, Butantã, SP 05508-000, Brazil; Departamento de Bioquímica, Instituto de Química (USP), Butantã, SP 05508-900, Brazil; Laboratório de Neurogenética, Universidade Federal do ABC, São Bernardo do Campo, SP 09210-580, Brazil
| | - Felipe José Costa Viana
- Laboratório de Neurofisiologia, Departamento de Fisiologia e Biofísica, Universidade de São Paulo, Butantã, SP 05508-000, Brazil
| | - Emily Cruvinel
- Laboratório de Neurofisiologia, Departamento de Fisiologia e Biofísica, Universidade de São Paulo, Butantã, SP 05508-000, Brazil
| | - Estevão Carlos-Lima
- Laboratório de Neurofisiologia, Departamento de Fisiologia e Biofísica, Universidade de São Paulo, Butantã, SP 05508-000, Brazil
| | - Fernando da Silva Borges
- Department of Physiology & Pharmacology, SUNY Downstate Health Sciences University, Brooklyn, NY 11203, USA
| | - Thais Tessari Zampieri
- Laboratório de Neurofisiologia, Departamento de Fisiologia e Biofísica, Universidade de São Paulo, Butantã, SP 05508-000, Brazil
| | - Fernanda Pereira Rebello
- Laboratório de Neurofisiologia, Departamento de Fisiologia e Biofísica, Universidade de São Paulo, Butantã, SP 05508-000, Brazil
| | - Henning Ulrich
- Departamento de Bioquímica, Instituto de Química (USP), Butantã, SP 05508-900, Brazil
| | - Roberto De Pasquale
- Laboratório de Neurofisiologia, Departamento de Fisiologia e Biofísica, Universidade de São Paulo, Butantã, SP 05508-000, Brazil.
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10
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Chiu DN, Carter BC. Synaptotagmin 7 Sculpts Short-Term Plasticity at a High Probability Synapse. J Neurosci 2024; 44:e1756232023. [PMID: 38262726 PMCID: PMC10904093 DOI: 10.1523/jneurosci.1756-23.2023] [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: 09/20/2023] [Revised: 11/20/2023] [Accepted: 12/15/2023] [Indexed: 01/25/2024] Open
Abstract
Synapses with high release probability (Pr ) tend to exhibit short-term synaptic depression. According to the prevailing model, this reflects the temporary depletion of release-ready vesicles after an initial action potential (AP). At the high-Pr layer 4 to layer 2/3 (L4-L2/3) synapse in rodent somatosensory cortex, short-term plasticity appears to contradict the depletion model: depression is absent at interstimulus intervals (ISIs) <50 ms and develops to a maximum at ∼200 ms. To understand the mechanism(s) underlying the biphasic time course of short-term plasticity at this synapse, we used whole-cell electrophysiology and two-photon calcium imaging in acute slices from male and female juvenile mice. We tested several candidate mechanisms including neuromodulation, postsynaptic receptor desensitization, and use-dependent changes in presynaptic AP-evoked calcium. We found that, at single L4-L2/3 synapses, Pr varies as a function of ISI, giving rise to the distinctive short-term plasticity time course. Furthermore, the higher-than-expected Pr at short ISIs depends on expression of synaptotagmin 7 (Syt7). Our results show that two distinct vesicle release processes summate to give rise to short-term plasticity at this synapse: (1) a basal, high-Pr release mechanism that undergoes rapid depression and recovers slowly (τ = ∼3 s) and (2) a Syt7-dependent mechanism that leads to a transient increase in Pr (τ = ∼100 ms) after the initial AP. We thus reveal how these synapses can maintain a very high probability of neurotransmission for multiple APs within a short time frame. Key words : depression; facilitation; short-term plasticity; synaptotagmin 7.
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Affiliation(s)
- Delia N Chiu
- European Neuroscience Institute Göttingen - A Joint Initiative of the University Medical Center Göttingen and the Max Planck Society, 37077 Göttingen, Germany
| | - Brett C Carter
- European Neuroscience Institute Göttingen - A Joint Initiative of the University Medical Center Göttingen and the Max Planck Society, 37077 Göttingen, Germany
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11
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Koppensteiner P, Bhandari P, Önal C, Borges-Merjane C, Le Monnier E, Roy U, Nakamura Y, Sadakata T, Sanbo M, Hirabayashi M, Rhee J, Brose N, Jonas P, Shigemoto R. GABA B receptors induce phasic release from medial habenula terminals through activity-dependent recruitment of release-ready vesicles. Proc Natl Acad Sci U S A 2024; 121:e2301449121. [PMID: 38346189 PMCID: PMC10895368 DOI: 10.1073/pnas.2301449121] [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: 01/26/2023] [Accepted: 01/03/2024] [Indexed: 02/15/2024] Open
Abstract
GABAB receptor (GBR) activation inhibits neurotransmitter release in axon terminals in the brain, except in medial habenula (MHb) terminals, which show robust potentiation. However, mechanisms underlying this enigmatic potentiation remain elusive. Here, we report that GBR activation on MHb terminals induces an activity-dependent transition from a facilitating, tonic to a depressing, phasic neurotransmitter release mode. This transition is accompanied by a 4.1-fold increase in readily releasable vesicle pool (RRP) size and a 3.5-fold increase of docked synaptic vesicles (SVs) at the presynaptic active zone (AZ). Strikingly, the depressing phasic release exhibits looser coupling distance than the tonic release. Furthermore, the tonic and phasic release are selectively affected by deletion of synaptoporin (SPO) and Ca2+-dependent activator protein for secretion 2 (CAPS2), respectively. SPO modulates augmentation, the short-term plasticity associated with tonic release, and CAPS2 retains the increased RRP for initial responses in phasic response trains. The cytosolic protein CAPS2 showed a SV-associated distribution similar to the vesicular transmembrane protein SPO, and they were colocalized in the same terminals. We developed the "Flash and Freeze-fracture" method, and revealed the release of SPO-associated vesicles in both tonic and phasic modes and activity-dependent recruitment of CAPS2 to the AZ during phasic release, which lasted several minutes. Overall, these results indicate that GBR activation translocates CAPS2 to the AZ along with the fusion of CAPS2-associated SVs, contributing to persistency of the RRP increase. Thus, we identified structural and molecular mechanisms underlying tonic and phasic neurotransmitter release and their transition by GBR activation in MHb terminals.
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Affiliation(s)
| | - Pradeep Bhandari
- Institute of Science and Technology Austria, Klosterneuburg3400, Austria
| | - Cihan Önal
- Institute of Science and Technology Austria, Klosterneuburg3400, Austria
| | | | - Elodie Le Monnier
- Institute of Science and Technology Austria, Klosterneuburg3400, Austria
| | - Utsa Roy
- Institute of Science and Technology Austria, Klosterneuburg3400, Austria
| | - Yukihiro Nakamura
- Department of Pharmacology, Jikei University School of Medicine, Nishishinbashi, Minato-ku, Tokyo105-8461, Japan
| | - Tetsushi Sadakata
- Advanced Scientific Research Leaders Development Unit, Gunma University Graduate School of Medicine, Maebashi, Gunma371-8511, Japan
| | - Makoto Sanbo
- Section of Mammalian Transgenesis, National Institute for Physiological Sciences, Okazaki444-8585, Japan
| | - Masumi Hirabayashi
- Section of Mammalian Transgenesis, National Institute for Physiological Sciences, Okazaki444-8585, Japan
| | - JeongSeop Rhee
- Department of Molecular Neurobiology, Max Planck Institute for Multidisciplinary Sciences, Göttingen37077, Germany
| | - Nils Brose
- Department of Molecular Neurobiology, Max Planck Institute for Multidisciplinary Sciences, Göttingen37077, Germany
| | - Peter Jonas
- Institute of Science and Technology Austria, Klosterneuburg3400, Austria
| | - Ryuichi Shigemoto
- Institute of Science and Technology Austria, Klosterneuburg3400, Austria
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12
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Yamaguchi J, Andrade MA, Truong TT, Toney GM. Glutamate Spillover Dynamically Strengthens Gabaergic Synaptic Inhibition of the Hypothalamic Paraventricular Nucleus. J Neurosci 2024; 44:e1851222023. [PMID: 38154957 PMCID: PMC10869154 DOI: 10.1523/jneurosci.1851-22.2023] [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: 09/29/2022] [Revised: 12/16/2023] [Accepted: 12/20/2023] [Indexed: 12/30/2023] Open
Abstract
The hypothalamic paraventricular nucleus (PVN) is strongly inhibited by γ-aminobutyric acid (GABA) from the surrounding peri-nuclear zone (PNZ). Because glutamate mediates fast excitatory transmission and is substrate for GABA synthesis, we tested its capacity to dynamically strengthen GABA inhibition. In PVN slices from male mice, bath glutamate applied during ionotropic glutamate receptor blockade increased PNZ-evoked inhibitory postsynaptic currents (eIPSCs) without affecting GABA-A receptor agonist currents or single-channel conductance, implicating a presynaptic mechanism(s). Consistent with this interpretation, bath glutamate failed to strengthen IPSCs during pharmacological saturation of GABA-A receptors. Presynaptic analyses revealed that glutamate did not affect paired-pulse ratio, peak eIPSC variability, GABA vesicle recycling speed, or readily releasable pool (RRP) size. Notably, glutamate-GABA strengthening (GGS) was unaffected by metabotropic glutamate receptor blockade and graded external Ca2+ when normalized to baseline amplitude. GGS was prevented by pan- but not glial-specific inhibition of glutamate uptake and by inhibition of glutamic acid decarboxylase (GAD), indicating reliance on glutamate uptake by neuronal excitatory amino acid transporter 3 (EAAT3) and enzymatic conversion of glutamate to GABA. EAAT3 immunoreactivity was strongly localized to presumptive PVN GABA terminals. High bath K+ also induced GGS, which was prevented by glutamate vesicle depletion, indicating that synaptic glutamate release strengthens PVN GABA inhibition. GGS suppressed PVN cell firing, indicating its functional significance. In sum, PVN GGS buffers neuronal excitation by apparent "over-filling" of vesicles with GABA synthesized from synaptically released glutamate. We posit that GGS protects against sustained PVN excitation and excitotoxicity while potentially aiding stress adaptation and habituation.
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Affiliation(s)
- Junya Yamaguchi
- Department of Cellular & Integrative Physiology, University of Texas Health San Antonio, San Antonio 78229-3900, Texas
| | - Mary Ann Andrade
- Department of Cellular & Integrative Physiology, University of Texas Health San Antonio, San Antonio 78229-3900, Texas
| | - Tamara T Truong
- Department of Cellular & Integrative Physiology, University of Texas Health San Antonio, San Antonio 78229-3900, Texas
| | - Glenn M Toney
- Department of Cellular & Integrative Physiology, University of Texas Health San Antonio, San Antonio 78229-3900, Texas
- Center for Biomedical Neuroscience, University of Texas Health San Antonio, San Antonio 78229-3900, Texas
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13
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Guhathakurta D, Petrušková A, Akdaş EY, Perelló-Amorós B, Frischknecht R, Anni D, Weiss EM, Walter M, Fejtová A. Hydroxynorketamine, but not ketamine, acts via α7 nicotinic acetylcholine receptor to control presynaptic function and gene expression. Transl Psychiatry 2024; 14:47. [PMID: 38253622 PMCID: PMC10803733 DOI: 10.1038/s41398-024-02744-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/20/2023] [Revised: 12/21/2023] [Accepted: 01/08/2024] [Indexed: 01/24/2024] Open
Abstract
Ketamine is clinically used fast-acting antidepressant. Its metabolite hydroxynorketamine (HNK) shows a robust antidepressant effect in animal studies. It is unclear, how these chemically distinct compounds converge on similar neuronal effects. While KET acts mostly as N-methyl-d-aspartate receptor (NMDAR) antagonist, the molecular target of HNK remains enigmatic. Here, we show that KET and HNK converge on rapid inhibition of glutamate release by reducing the release competence of synaptic vesicles and induce nuclear translocation of pCREB that controls expression of neuroplasticity genes connected to KET- and HNK-mediated antidepressant action. Ro25-6981, a selective antagonist of GluN2B, mimics effect of KET indicating that GluN2B-containing NMDAR might mediate the presynaptic effect of KET. Selective antagonist of α7 nicotinic acetylcholine receptors (α7nAChRs) or genetic deletion of Chrna7, its pore-forming subunit, fully abolishes HNK-induced synaptic and nuclear regulations, but leaves KET-dependent cellular effects unaffected. Thus, KET or HNK-induced modulation of synaptic transmission and nuclear translocation of pCREB can be mediated by selective signaling via NMDAR or α7nAChRs, respectively. Due to the rapid metabolism of KET to HNK, it is conceivable that subsequent modulation of glutamatergic and cholinergic neurotransmission affects circuits in a cell-type-specific manner and contributes to the therapeutic potency of KET. This finding promotes further exploration of new combined medications for mood disorders.
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Affiliation(s)
- Debarpan Guhathakurta
- Department of Psychiatry and Psychotherapy, Universitätsklinikum Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany
| | - Aneta Petrušková
- Department of Psychiatry and Psychotherapy, Universitätsklinikum Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany
- National Institute of Mental Health, Klecany, Czech Republic
- Third Faculty of Medicine, Charles University, Prague, Czech Republic
| | - Enes Yağız Akdaş
- Department of Psychiatry and Psychotherapy, Universitätsklinikum Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany
| | - Bartomeu Perelló-Amorós
- Department of Biology, Animal Physiology, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany
| | - Renato Frischknecht
- Department of Biology, Animal Physiology, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany
| | - Daniela Anni
- Department of Psychiatry and Psychotherapy, Universitätsklinikum Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany
| | - Eva-Maria Weiss
- Department of Psychiatry and Psychotherapy, Universitätsklinikum Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany
| | - Martin Walter
- Department of Psychiatry and Psychotherapy, Universitätsklinikum Jena, Jena, Germany
| | - Anna Fejtová
- Department of Psychiatry and Psychotherapy, Universitätsklinikum Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany.
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14
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Sun L, Qu S, Xu W. A retinomorphic neuron for artificial vision and iris accommodation. MATERIALS HORIZONS 2023; 10:5753-5762. [PMID: 37807818 DOI: 10.1039/d3mh01036h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/10/2023]
Abstract
The iris of an eye automatically optimizes the amount of light that strikes the retina by accommodating the intensity of ambient light. Here, we describe a retinomorphic neuron using neuromorphic photoreceptors for artificial vision and iris accommodation that mimics the biological structure and processing functions of retinal neurons for light sensing and signal transduction. The system consists of a neuromorphic photoreceptor, an electrochromic device as a light filter, and a spike-generation unit. In particular, the Au nanoparticle (NP) decorated ITO fiber photoreceptor with a well-aligned array structure is able to rely on its own light-tunable synaptic plasticity and the plasmon-enhanced light absorption. Therefore, it allows real-time feedback about light intensity, emits a higher-frequency electrical stimulus to stronger light, flash, or prolonged light illumination time, and drives the electrochromic filter to work, allowing mild light to pass through. Compared with traditional artificial irises or artificial photoreceptors, our design introduces neural pathways and neuromorphic devices, which are closer to biological functions in simulation. To our knowledge, this is the first time that a retinal neuron with neuromorphic photoreceptors has been used for artificial iris vision. Furthermore, we demonstrate direct and consensual pupillary light reflexes. The design of artificial iris vision has potential applications in biomimetic engineering, smart interaction, and visual prostheses.
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Affiliation(s)
- Lin Sun
- Institute of Photoelectronic Thin Film Devices and Technology, Key Laboratory of Optoelectronic Thin Film Devices and Technology of Tianjin, College of Electrical Information and Optical Engineering, Engineering Research Center of Thin Film Photoelectronic Technology of Ministry of Education, Smart Sensing Interdisciplinary Science Center, Nankai University, Tianjin 300350, China.
- Shenzhen Research Institute of Nankai University, Shenzhen 518000, China
| | - Shangda Qu
- Institute of Photoelectronic Thin Film Devices and Technology, Key Laboratory of Optoelectronic Thin Film Devices and Technology of Tianjin, College of Electrical Information and Optical Engineering, Engineering Research Center of Thin Film Photoelectronic Technology of Ministry of Education, Smart Sensing Interdisciplinary Science Center, Nankai University, Tianjin 300350, China.
- Shenzhen Research Institute of Nankai University, Shenzhen 518000, China
| | - Wentao Xu
- Institute of Photoelectronic Thin Film Devices and Technology, Key Laboratory of Optoelectronic Thin Film Devices and Technology of Tianjin, College of Electrical Information and Optical Engineering, Engineering Research Center of Thin Film Photoelectronic Technology of Ministry of Education, Smart Sensing Interdisciplinary Science Center, Nankai University, Tianjin 300350, China.
- Shenzhen Research Institute of Nankai University, Shenzhen 518000, China
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15
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Dunn TW, Fan X, Lee J, Smith P, Gandhi R, Sossin WS. The role of specific isoforms of Ca V2 and the common C-terminal of Ca V2 in calcium channel function in sensory neurons of Aplysia. Sci Rep 2023; 13:20216. [PMID: 37980443 PMCID: PMC10657410 DOI: 10.1038/s41598-023-47573-z] [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: 06/19/2023] [Accepted: 11/15/2023] [Indexed: 11/20/2023] Open
Abstract
The presynaptic release apparatus can be specialized to enable specific synaptic functions. Habituation is the diminishing of a physiological response to a frequently repeated stimulus and in Aplysia, habituation to touch is mediated by a decrease in transmitter release from the sensory neurons that respond to touch even after modest rates of action potential firing. This synaptic depression is not common among Aplysia synaptic connections suggesting the presence of a release apparatus specialized for this depression. We found that specific splice forms of ApCaV2, the calcium channel required for transmitter release, are preferentially used in sensory neurons, consistent with a specialized release apparatus. However, we were not able to find a specific ApCaV2 splice uniquely required for synaptic depression. The C-terminus of ApCaV2 alpha1 subunit retains conserved binding to Aplysia rab-3 interacting molecule (ApRIM) and ApRIM-binding protein (ApRBP) and the C-terminus is required for full synaptic expression of ApCaV2. We also identified a splice form of ApRIM that did not interact with the ApCav2 alpha 1 subunit, but it was not preferentially used in sensory neurons.
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Affiliation(s)
- Tyler W Dunn
- Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, Montreal, QC, H3A 2B4, Canada
| | - Xiaotang Fan
- Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, Montreal, QC, H3A 2B4, Canada
| | - Jiwon Lee
- Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, Montreal, QC, H3A 2B4, Canada
| | - Petranea Smith
- Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, Montreal, QC, H3A 2B4, Canada
| | - Rushali Gandhi
- Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, Montreal, QC, H3A 2B4, Canada
| | - Wayne S Sossin
- Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, Montreal, QC, H3A 2B4, Canada.
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16
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Jetti SK, Crane AB, Akbergenova Y, Aponte-Santiago NA, Cunningham KL, Whittaker CA, Littleton JT. Molecular logic of synaptic diversity between Drosophila tonic and phasic motoneurons. Neuron 2023; 111:3554-3569.e7. [PMID: 37611584 DOI: 10.1016/j.neuron.2023.07.019] [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: 01/17/2023] [Revised: 05/22/2023] [Accepted: 07/28/2023] [Indexed: 08/25/2023]
Abstract
Although neuronal subtypes display unique synaptic organization and function, the underlying transcriptional differences that establish these features are poorly understood. To identify molecular pathways that contribute to synaptic diversity, single-neuron Patch-seq RNA profiling was performed on Drosophila tonic and phasic glutamatergic motoneurons. Tonic motoneurons form weaker facilitating synapses onto single muscles, while phasic motoneurons form stronger depressing synapses onto multiple muscles. Super-resolution microscopy and in vivo imaging demonstrated that synaptic active zones in phasic motoneurons are more compact and display enhanced Ca2+ influx compared with their tonic counterparts. Genetic analysis identified unique synaptic properties that mapped onto gene expression differences for several cellular pathways, including distinct signaling ligands, post-translational modifications, and intracellular Ca2+ buffers. These findings provide insights into how unique transcriptomes drive functional and morphological differences between neuronal subtypes.
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Affiliation(s)
- Suresh K Jetti
- The Picower Institute for Learning and Memory, Department of Biology and Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.
| | - Andrés B Crane
- The Picower Institute for Learning and Memory, Department of Biology and Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Yulia Akbergenova
- The Picower Institute for Learning and Memory, Department of Biology and Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Nicole A Aponte-Santiago
- The Picower Institute for Learning and Memory, Department of Biology and Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Karen L Cunningham
- The Picower Institute for Learning and Memory, Department of Biology and Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Charles A Whittaker
- Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - J Troy Littleton
- The Picower Institute for Learning and Memory, Department of Biology and Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.
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17
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Chien VSC, Wang P, Maess B, Fishman Y, Knösche TR. Laminar neural dynamics of auditory evoked responses: Computational modeling of local field potentials in auditory cortex of non-human primates. Neuroimage 2023; 281:120364. [PMID: 37683810 DOI: 10.1016/j.neuroimage.2023.120364] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2023] [Revised: 08/15/2023] [Accepted: 09/04/2023] [Indexed: 09/10/2023] Open
Abstract
Evoked neural responses to sensory stimuli have been extensively investigated in humans and animal models both to enhance our understanding of brain function and to aid in clinical diagnosis of neurological and neuropsychiatric conditions. Recording and imaging techniques such as electroencephalography (EEG), magnetoencephalography (MEG), local field potentials (LFPs), and calcium imaging provide complementary information about different aspects of brain activity at different spatial and temporal scales. Modeling and simulations provide a way to integrate these different types of information to clarify underlying neural mechanisms. In this study, we aimed to shed light on the neural dynamics underlying auditory evoked responses by fitting a rate-based model to LFPs recorded via multi-contact electrodes which simultaneously sampled neural activity across cortical laminae. Recordings included neural population responses to best-frequency (BF) and non-BF tones at four representative sites in primary auditory cortex (A1) of awake monkeys. The model considered major neural populations of excitatory, parvalbumin-expressing (PV), and somatostatin-expressing (SOM) neurons across layers 2/3, 4, and 5/6. Unknown parameters, including the connection strength between the populations, were fitted to the data. Our results revealed similar population dynamics, fitted model parameters, predicted equivalent current dipoles (ECD), tuning curves, and lateral inhibition profiles across recording sites and animals, in spite of quite different extracellular current distributions. We found that PV firing rates were higher in BF than in non-BF responses, mainly due to different strengths of tonotopic thalamic input, whereas SOM firing rates were higher in non-BF than in BF responses due to lateral inhibition. In conclusion, we demonstrate the feasibility of the model-fitting approach in identifying the contributions of cell-type specific population activity to stimulus-evoked LFPs across cortical laminae, providing a foundation for further investigations into the dynamics of neural circuits underlying cortical sensory processing.
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Affiliation(s)
- Vincent S C Chien
- Max Planck Institute for Human Cognitive and Brain Sciences, Germany; Institute of Computer Science of the Czech Academy of Sciences, Czech Republic
| | - Peng Wang
- Max Planck Institute for Human Cognitive and Brain Sciences, Germany; Institute of Psychology, University of Greifswald, Germany; Institute of Psychology, University of Regensburg, Germany
| | - Burkhard Maess
- Max Planck Institute for Human Cognitive and Brain Sciences, Germany
| | - Yonatan Fishman
- Departments of Neurology and Neuroscience, Albert Einstein College of Medicine, USA
| | - Thomas R Knösche
- Max Planck Institute for Human Cognitive and Brain Sciences, Germany.
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18
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Juárez EH, Wood CR, Davies R, Kehoe O, Johnson WEB, Merighi A, Ferrini F. ST2-Conditioned Medium Fosters Dorsal Horn Cell Excitability and Synaptic Transmission in Cultured Mouse Spinal Cord. Stem Cell Rev Rep 2023; 19:2918-2928. [PMID: 37674016 PMCID: PMC10661801 DOI: 10.1007/s12015-023-10618-x] [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] [Accepted: 08/28/2023] [Indexed: 09/08/2023]
Abstract
Conditioned medium obtained from bone marrow-derived stem cells has been proposed as a novel cell-free therapy in spinal cord injury and neuropathic pain, yet the direct effect on spinal neuron function has never been investigated. Here, we adopted spinal cord organotypic cultures (SCOCs) as an experimental model to probe the effect of ST2 murine mesenchymal stem cells-conditioned medium (ST2-CM) on dorsal horn (DH) neuron functional properties. Three days of SCOC exposure to ST2-CM increased neuronal activity measured by Fos expression, as well as spontaneous or induced firing. We showed that the increase in neuronal excitability was associated with changes in both intrinsic membrane properties and an enhanced excitatory drive. The increased excitability at the single-cell level was substantiated at the network level by detecting synchronous bursts of calcium waves across DH neurons. Altogether, SCOCs represent a viable tool to probe mesenchymal cells' effect on intact neuronal networks. Our findings indicate that ST2-CM enhances neuronal activity and synaptic wiring in the spinal dorsal horn. Our data also support the trophic role of mesenchymal cells CM in maintaining network activity in spinal circuits.
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Affiliation(s)
- Esri H Juárez
- Department of Veterinary Sciences, University of Turin, Largo Paolo Braccini 2, I-10095, Grugliasco, TO, Italy
| | - Chelsea R Wood
- Chester Medical School, University of Chester, Parkgate Road, Chester, CH1 4BJ, UK
- School of Life Sciences, Coventry University, Coventry, CV1 2DS, UK
| | - Rebecca Davies
- Centre for Regenerative Medicine Research, School of Medicine, Keele University, Keele, Staffordshire, ST5 5BG, UK
- Robert Jones and Agnes Hunt Orthopaedic Hospital, Oswestry, Shropshire, SY10 7AG, UK
| | - Oksana Kehoe
- Centre for Regenerative Medicine Research, School of Medicine, Keele University, Keele, Staffordshire, ST5 5BG, UK
- Robert Jones and Agnes Hunt Orthopaedic Hospital, Oswestry, Shropshire, SY10 7AG, UK
| | - William E B Johnson
- Chester Medical School, University of Chester, Parkgate Road, Chester, CH1 4BJ, UK
| | - Adalberto Merighi
- Department of Veterinary Sciences, University of Turin, Largo Paolo Braccini 2, I-10095, Grugliasco, TO, Italy
| | - Francesco Ferrini
- Department of Veterinary Sciences, University of Turin, Largo Paolo Braccini 2, I-10095, Grugliasco, TO, Italy.
- Department of Psychiatry and Neuroscience, Université Laval, Québec, G1K 7P4, Canada.
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19
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Dahlmanns M, Valero-Aracama MJ, Dahlmanns JK, Zheng F, Alzheimer C. Tonic activin signaling shapes cellular and synaptic properties of CA1 neurons mainly in dorsal hippocampus. iScience 2023; 26:108001. [PMID: 37829200 PMCID: PMC10565779 DOI: 10.1016/j.isci.2023.108001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2023] [Revised: 08/07/2023] [Accepted: 09/18/2023] [Indexed: 10/14/2023] Open
Abstract
Dorsal and ventral hippocampus serve different functions in cognition and affective behavior, but the underpinnings of this diversity at the cellular and synaptic level are not well understood. We found that the basal level of activin A, a member of the TGF-β family, which regulates hippocampal circuits in a behaviorally relevant fashion, is much higher in dorsal than in ventral hippocampus. Using transgenic mice with a forebrain-specific disruption of activin receptor signaling, we identified the pronounced dorsal-ventral gradient of activin A as a major factor determining the distinct neurophysiologic signatures of dorsal and ventral hippocampus, ranging from pyramidal cell firing, tuning of frequency-dependent synaptic facilitation, to long-term potentiation (LTP), long-term depression (LTD), and de-potentiation. Thus, the strong activin A tone in dorsal hippocampus appears crucial to establish cellular and synaptic phenotypes that are tailored specifically to the respective network operations in dorsal and ventral hippocampus.
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Affiliation(s)
- Marc Dahlmanns
- Institute of Physiology and Pathophysiology, Friedrich-Alexander-Universität Erlangen-Nürnberg, 91054 Erlangen, Germany
| | - Maria Jesus Valero-Aracama
- Institute of Physiology and Pathophysiology, Friedrich-Alexander-Universität Erlangen-Nürnberg, 91054 Erlangen, Germany
| | - Jana Katharina Dahlmanns
- Institute of Physiology and Pathophysiology, Friedrich-Alexander-Universität Erlangen-Nürnberg, 91054 Erlangen, Germany
| | - Fang Zheng
- Institute of Physiology and Pathophysiology, Friedrich-Alexander-Universität Erlangen-Nürnberg, 91054 Erlangen, Germany
| | - Christian Alzheimer
- Institute of Physiology and Pathophysiology, Friedrich-Alexander-Universität Erlangen-Nürnberg, 91054 Erlangen, Germany
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20
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Lombardi A, Wang Q, Stüttgen MC, Mittmann T, Luhmann HJ, Kilb W. Recovery kinetics of short-term depression of GABAergic and glutamatergic synapses at layer 2/3 pyramidal cells in the mouse barrel cortex. Front Cell Neurosci 2023; 17:1254776. [PMID: 37817883 PMCID: PMC10560857 DOI: 10.3389/fncel.2023.1254776] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2023] [Accepted: 09/11/2023] [Indexed: 10/12/2023] Open
Abstract
Introduction Short-term synaptic plasticity (STP) is a widespread mechanism underlying activity-dependent modifications of cortical networks. Methods To investigate how STP influences excitatory and inhibitory synapses in layer 2/3 of mouse barrel cortex, we combined whole-cell patch-clamp recordings from visually identified pyramidal neurons (PyrN) and parvalbumin-positive interneurons (PV-IN) of cortical layer 2/3 in acute slices with electrical stimulation of afferent fibers in layer 4 and optogenetic activation of PV-IN. Results These experiments revealed that electrical burst stimulation (10 pulses at 10 Hz) of layer 4 afferents to layer 2/3 neurons induced comparable short-term depression (STD) of glutamatergic postsynaptic currents (PSCs) in PyrN and in PV-IN, while disynaptic GABAergic PSCs in PyrN showed a stronger depression. Burst-induced depression of glutamatergic PSCs decayed within <4 s, while the decay of GABAergic PSCs required >11 s. Optogenetically-induced GABAergic PSCs in PyrN also demonstrated STD after burst stimulation, with a decay of >11 s. Excitatory postsynaptic potentials (EPSPs) in PyrN were unaffected after electrical burst stimulation, while a selective optogenetic STD of GABAergic synapses caused a transient increase of electrically evoked EPSPs in PyrN. Discussion In summary, these results demonstrate substantial short-term plasticity at all synapses investigated and suggest that the prominent STD observed in GABAergic synapses can moderate the functional efficacy of glutamatergic STD after repetitive synaptic stimulations. This mechanism may contribute to a reliable information flow toward the integrative layer 2/3 for complex time-varying sensory stimuli.
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Affiliation(s)
- Aniello Lombardi
- Institute of Physiology, University Medical Center of the Johannes Gutenberg University, Mainz, Germany
| | - Qiang Wang
- Institute of Physiology, University Medical Center of the Johannes Gutenberg University, Mainz, Germany
| | - Maik C. Stüttgen
- Institute of Pathophysiology, University Medical Center of the Johannes Gutenberg University, Mainz, Germany
| | - Thomas Mittmann
- Institute of Physiology, University Medical Center of the Johannes Gutenberg University, Mainz, Germany
| | - Heiko J. Luhmann
- Institute of Physiology, University Medical Center of the Johannes Gutenberg University, Mainz, Germany
| | - Werner Kilb
- Institute of Physiology, University Medical Center of the Johannes Gutenberg University, Mainz, Germany
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21
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Nagaraja RY, Stiles MA, Sherry DM, Agbaga MP, Ahmad M. Synapse-Specific Defects in Synaptic Transmission in the Cerebellum of W246G Mutant ELOVL4 Rats-a Model of Human SCA34. J Neurosci 2023; 43:5963-5974. [PMID: 37491316 PMCID: PMC10436685 DOI: 10.1523/jneurosci.0378-23.2023] [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: 03/01/2023] [Revised: 06/30/2023] [Accepted: 07/20/2023] [Indexed: 07/27/2023] Open
Abstract
Elongation of very long fatty acids-4 (ELOVL4) mediates biosynthesis of very long chain-fatty acids (VLC-FA; ≥28 carbons). Various mutations in this enzyme result in spinocerebellar ataxia-34 (SCA34). We generated a rat model of human SCA34 by knock-in of a naturally occurring c.736T>G, p.W246G mutation in the Elovl4 gene. Our previous analysis of homozygous W246G mutant ELOVL4 rats (MUT) revealed early-onset gait disturbance and impaired synaptic transmission and plasticity at parallel fiber-Purkinje cell (PF-PC) and climbing fiber-Purkinje cell (CF-PC) synapses. However, the underlying mechanisms that caused these defects remained unknown. Here, we report detailed patch-clamp recordings from Purkinje cells that identify impaired synaptic mechanisms. Our results show that miniature EPSC (mEPSC) frequency is reduced in MUT rats with no change in mEPSC amplitude, suggesting a presynaptic defect of excitatory synaptic transmission on Purkinje cells. We also find alterations in inhibitory synaptic transmission as miniature IPSC (mIPSC) frequency and amplitude are increased in MUT Purkinje cells. Paired-pulse ratio is reduced at PF-PC synapses but increased at CF-PC synapses in MUT rats, which along with results from high-frequency stimulation suggest opposite changes in the release probability at these two synapses. In contrast, we identify exaggerated persistence of EPSC amplitude at CF-PC and PF-PC synapses in MUT cerebellum, suggesting a larger readily releasable pool (RRP) at both synapses. Furthermore, the dendritic spine density is reduced in MUT Purkinje cells. Thus, our results uncover novel mechanisms of action of VLC-FA at cerebellar synapses, and elucidate the synaptic dysfunction underlying SCA34 pathology.SIGNIFICANCE STATEMENT Very long chain-fatty acids (VLC-FA) are an understudied class of fatty acids that are present in the brain. They are critical for brain function as their deficiency caused by mutations in elongation of very long fatty acids-4 (ELOVL4), the enzyme that mediates their biosynthesis, results in neurologic diseases including spinocerebellar ataxia-34 (SCA34), neuroichthyosis, and Stargardt-like macular dystrophy. In this study, we investigated the synaptic defects present in a rat model of SCA34 and identified defects in presynaptic neurotransmitter release and dendritic spine density at synapses in the cerebellum, a brain region involved in motor coordination. These results advance our understanding of the synaptic mechanisms regulated by VLC-FA and describe the synaptic dysfunction that leads to motor incoordination in SCA34.
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Affiliation(s)
- Raghavendra Y Nagaraja
- Department of Cell Biology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma 73104
- Department of Ophthalmology, Dean McGee Eye Institute, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma 73104
| | - Megan A Stiles
- Department of Ophthalmology, Dean McGee Eye Institute, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma 73104
| | - David M Sherry
- Department of Cell Biology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma 73104
- Department of Neurosurgery, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma 73104
- Department of Pharmaceutical Sciences, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma 73104
| | - Martin-Paul Agbaga
- Department of Cell Biology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma 73104
- Department of Ophthalmology, Dean McGee Eye Institute, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma 73104
| | - Mohiuddin Ahmad
- Department of Cell Biology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma 73104
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22
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Baek MH, Kim H. Polysilicon-Channel Synaptic Transistors for Implementation of Short- and Long-Term Memory Characteristics. Biomimetics (Basel) 2023; 8:368. [PMID: 37622973 PMCID: PMC10452842 DOI: 10.3390/biomimetics8040368] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2023] [Revised: 07/28/2023] [Accepted: 08/12/2023] [Indexed: 08/26/2023] Open
Abstract
The rapid progress of artificial neural networks (ANN) is largely attributed to the development of the rectified linear unit (ReLU) activation function. However, the implementation of software-based ANNs, such as convolutional neural networks (CNN), within the von Neumann architecture faces limitations due to its sequential processing mechanism. To overcome this challenge, research on hardware neuromorphic systems based on spiking neural networks (SNN) has gained significant interest. Artificial synapse, a crucial building block in these systems, has predominantly utilized resistive memory-based memristors. However, the two-terminal structure of memristors presents difficulties in processing feedback signals from the post-synaptic neuron, and without an additional rectifying device it is challenging to prevent sneak current paths. In this paper, we propose a four-terminal synaptic transistor with an asymmetric dual-gate structure as a solution to the limitations of two-terminal memristors. Similar to biological synapses, the proposed device multiplies the presynaptic input signal with stored synaptic weight information and transmits the result to the postsynaptic neuron. Weight modulation is explored through both hot carrier injection (HCI) and Fowler-Nordheim (FN) tunneling. Moreover, we investigate the incorporation of short-term memory properties by adopting polysilicon grain boundaries as temporary storage. It is anticipated that the devised synaptic devices, possessing both short-term and long-term memory characteristics, will enable the implementation of various novel ANN algorithms.
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Affiliation(s)
- Myung-Hyun Baek
- Department of Electronic Engineering, Gangneung-Wonju National University, Gangneung 25457, Republic of Korea;
| | - Hyungjin Kim
- Department of Electrical and Computer Engineering, Inha University, Incheon 22212, Republic of Korea
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23
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Asopa A, Bhalla US. A computational view of short-term plasticity and its implications for E-I balance. Curr Opin Neurobiol 2023; 81:102729. [PMID: 37245258 DOI: 10.1016/j.conb.2023.102729] [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: 08/04/2022] [Revised: 03/30/2023] [Accepted: 04/25/2023] [Indexed: 05/30/2023]
Abstract
Short-term plasticity (STP) and excitatory-inhibitory balance (EI balance) are both ubiquitous building blocks of brain circuits across the animal kingdom. The synapses involved in EI are also subject to short-term plasticity, and several experimental studies have shown that their effects overlap. Recent computational and theoretical work has begun to highlight the functional implications of the intersection of these motifs. The findings are nuanced: while there are general computational themes, such as pattern tuning, normalization, and gating, much of the richness of these interactions comes from region- and modality specific tuning of STP properties. Together these findings point towards the STP-EI balance combination as being a versatile and highly efficient neural building block for a wide range of pattern-specific responses.
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Affiliation(s)
- Aditya Asopa
- National Centre for Biological Sciences, Tata Institute of Fundamental Research, Bellary Road, Bengaluru, 560065, India. https://twitter.com/adityaasopa
| | - Upinder S Bhalla
- National Centre for Biological Sciences, Tata Institute of Fundamental Research, Bellary Road, Bengaluru, 560065, India.
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24
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Venturini M, Cherchi F, Santalmasi C, Frulloni L, Dettori I, Catarzi D, Pedata F, Colotta V, Varano F, Coppi E, Pugliese AM. Pharmacological Characterization of P626, a Novel Dual Adenosine A 2A/A 2B Receptor Antagonist, on Synaptic Plasticity and during an Ischemic-like Insult in CA1 Rat Hippocampus. Biomolecules 2023; 13:894. [PMID: 37371474 DOI: 10.3390/biom13060894] [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: 03/24/2023] [Revised: 05/24/2023] [Accepted: 05/25/2023] [Indexed: 06/29/2023] Open
Abstract
In recent years, the use of multi-target compounds has become an increasingly pursued strategy to treat complex pathologies, including cerebral ischemia. Adenosine and its receptors (A1AR, A2AAR, A2BAR, A3AR) are known to play a crucial role in synaptic transmission either in normoxic or ischemic-like conditions. Previous data demonstrate that the selective antagonism of A2AAR or A2BAR delays anoxic depolarization (AD) appearance, an unequivocal sign of neuronal injury induced by a severe oxygen-glucose deprivation (OGD) insult in the hippocampus. Furthermore, the stimulation of A2AARs or A2BARs by respective selective agonists, CGS21680 and BAY60-6583, increases pre-synaptic neurotransmitter release, as shown by the decrease in paired-pulse facilitation (PPF) at Schaffer collateral-CA1 synapses. In the present research, we investigated the effect/s of the newly synthesized dual A2AAR/A2BAR antagonist, P626, in preventing A2AAR- and/or A2BAR-mediated effects by extracellular recordings of synaptic potentials in the CA1 rat hippocampal slices. We demonstrated that P626 prevented PPF reduction induced by CGS21680 or BAY60-6583 and delayed, in a concentration-dependent manner, AD appearance during a severe OGD. In conclusion, P626 may represent a putative neuroprotective compound for stroke treatment with the possible translational advantage of reducing side effects and bypassing differences in pharmacokinetics due to combined treatment.
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Affiliation(s)
- Martina Venturini
- Department of Neuroscience, Psychology, Drug Research and Child Health (NEUROFARBA), Section of Pharmacology and Toxicology, University of Florence, 50139 Florence, Italy
| | - Federica Cherchi
- Department of Neuroscience, Psychology, Drug Research and Child Health (NEUROFARBA), Section of Pharmacology and Toxicology, University of Florence, 50139 Florence, Italy
| | - Clara Santalmasi
- Department of Neuroscience, Psychology, Drug Research and Child Health (NEUROFARBA), Section of Pharmacology and Toxicology, University of Florence, 50139 Florence, Italy
| | - Lucia Frulloni
- Department of Neuroscience, Psychology, Drug Research and Child Health (NEUROFARBA), Section of Pharmacology and Toxicology, University of Florence, 50139 Florence, Italy
| | - Ilaria Dettori
- Department of Neuroscience, Psychology, Drug Research and Child Health (NEUROFARBA), Section of Pharmacology and Toxicology, University of Florence, 50139 Florence, Italy
| | - Daniela Catarzi
- Department of Neuroscience, Psychology, Drug Research and Child Health (NEUROFARBA), Section of Pharmaceutical and Nutraceutical Sciences, University of Florence, 50019 Sesto Fiorentino, Italy
| | - Felicita Pedata
- Department of Neuroscience, Psychology, Drug Research and Child Health (NEUROFARBA), Section of Pharmacology and Toxicology, University of Florence, 50139 Florence, Italy
| | - Vittoria Colotta
- Department of Neuroscience, Psychology, Drug Research and Child Health (NEUROFARBA), Section of Pharmaceutical and Nutraceutical Sciences, University of Florence, 50019 Sesto Fiorentino, Italy
| | - Flavia Varano
- Department of Neuroscience, Psychology, Drug Research and Child Health (NEUROFARBA), Section of Pharmaceutical and Nutraceutical Sciences, University of Florence, 50019 Sesto Fiorentino, Italy
| | - Elisabetta Coppi
- Department of Neuroscience, Psychology, Drug Research and Child Health (NEUROFARBA), Section of Pharmacology and Toxicology, University of Florence, 50139 Florence, Italy
| | - Anna Maria Pugliese
- Department of Neuroscience, Psychology, Drug Research and Child Health (NEUROFARBA), Section of Pharmacology and Toxicology, University of Florence, 50139 Florence, Italy
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25
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Jiang ZJ, Gong LW. The SphK1/S1P Axis Regulates Synaptic Vesicle Endocytosis via TRPC5 Channels. J Neurosci 2023; 43:3807-3824. [PMID: 37185099 PMCID: PMC10217994 DOI: 10.1523/jneurosci.1494-22.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2022] [Revised: 04/13/2023] [Accepted: 04/17/2023] [Indexed: 05/17/2023] Open
Abstract
Sphingosine-1-phosphate (S1P), a bioactive sphingolipid concentrated in the brain, is essential for normal brain functions, such as learning and memory and feeding behaviors. Sphingosine kinase 1 (SphK1), the primary kinase responsible for S1P production in the brain, is abundant within presynaptic terminals, indicating a potential role of the SphK1/S1P axis in presynaptic physiology. Altered S1P levels have been highlighted in many neurologic diseases with endocytic malfunctions. However, it remains unknown whether the SphK1/S1P axis may regulate synaptic vesicle endocytosis in neurons. The present study evaluates potential functions of the SphK1/S1P axis in synaptic vesicle endocytosis by determining effects of a dominant negative catalytically inactive SphK1. Our data for the first time identify a critical role of the SphK1/S1P axis in endocytosis in both neuroendocrine chromaffin cells and neurons from mice of both sexes. Furthermore, our Ca2+ imaging data indicate that the SphK1/S1P axis may be important for presynaptic Ca2+ increases during prolonged stimulations by regulating the Ca2+ permeable TRPC5 channels, which per se regulate synaptic vesicle endocytosis. Collectively, our data point out a critical role of the regulation of TRPC5 by the SphK1/S1P axis in synaptic vesicle endocytosis.SIGNIFICANCE STATEMENT Sphingosine kinase 1 (SphK1), the primary kinase responsible for brain sphingosine-1-phosphate (S1P) production, is abundant within presynaptic terminals. Altered SphK1/S1P metabolisms has been highlighted in many neurologic disorders with defective synaptic vesicle endocytosis. However, whether the SphK1/S1P axis may regulate synaptic vesicle endocytosis is unknown. Here, we identify that the SphK1/S1P axis regulates the kinetics of synaptic vesicle endocytosis in neurons, in addition to controlling fission-pore duration during single vesicle endocytosis in neuroendocrine chromaffin cells. The regulation of the SphK1/S1P axis in synaptic vesicle endocytosis is specific since it has a distinguished signaling pathway, which involves regulation of Ca2+ influx via TRPC5 channels. This discovery may provide novel mechanistic implications for the SphK1/S1P axis in brain functions under physiological and pathologic conditions.
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Affiliation(s)
- Zhong-Jiao Jiang
- Department of Biological Sciences, University of Illinois Chicago, Chicago, Illinois 60607
| | - Liang-Wei Gong
- Department of Biological Sciences, University of Illinois Chicago, Chicago, Illinois 60607
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26
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Kawabata R, Yamanaka H, Kobayashi K, Oke Y, Fujita A, Oku Y, Yao I, Koga K. The anterior cingulate cortex is critical for acute stress-induced hypersensitivity in mice. Neuroscience 2023:S0306-4522(23)00221-X. [PMID: 37211084 DOI: 10.1016/j.neuroscience.2023.05.010] [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: 02/21/2023] [Revised: 05/04/2023] [Accepted: 05/14/2023] [Indexed: 05/23/2023]
Abstract
Stress can be categorized according to physical, psychological and social factors. Exposure to stress produces stress-induced hypersensitivity and forms negative emotions such as anxiety and depression. For example, acute physical stress induced by the elevated open platform (EOP) causes prolonged mechanical hypersensitivity. The anterior cingulate cortex (ACC) is a cortical region involved in pain and negative emotions. Recently, we showed that mice exposed to the EOP changed spontaneous excitatory, but not inhibitory transmission in layer II/III pyramidal neurons of the ACC. However, it is still unclear whether the ACC is involved in the EOP induced mechanical hypersensitivity, and how the EOP alters evoked synaptic transmission on excitatory and inhibitory synaptic transmission in the ACC. In this study, we injected ibotenic acid into the ACC to examine if it was involved in stress-induced mechanical hypersensitivity induced by EOP exposure. Next, by using whole-cell patch-clamp recording from brain slice preparation, we analyzed action potentials and evoked synaptic transmission from layer II/III pyramidal neurons within the ACC. Lesion of the ACC completely blocked the stress-induced mechanical hypersensitivity induced by EOP exposure. Mechanistically, EOP exposure mainly altered evoked excitatory postsynaptic currents such as input-output and paired pulse ratio. Intriguingly, the mice exposed in the EOP also produced low-frequency stimulation induced short-term depression on excitatory synapses in the ACC. These results suggest that the ACC plays a critical role in the modulation of stress-induced mechanical hypersensitivity, possibly through synaptic plasticity on excitatory transmission.
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Affiliation(s)
- Ryo Kawabata
- Biomedical Chemistry major, Graduate School of Science and Technology, Kwansei Gakuin University, Sanda, Hyogo 669-1330, Japan; Department of Neurophysiology, Faculty of Medicine, Hyogo Medical University, Nishinomiya, Hyogo 663-8501, Japan
| | - Hiroki Yamanaka
- Department of Anatomy and Neuroscience, Faculty of Medicine, Hyogo Medical University, Nishinomiya, Hyogo 663-8501, Japan
| | - Kimiko Kobayashi
- Department of Anatomy and Neuroscience, Faculty of Medicine, Hyogo Medical University, Nishinomiya, Hyogo 663-8501, Japan
| | - Yoshihiko Oke
- Department of Physiology, Faculty of Medicine, Hyogo Medical University, Nishinomiya, Hyogo 663-8501, Japan
| | - Ayumi Fujita
- Department of Neurophysiology, Faculty of Medicine, Hyogo Medical University, Nishinomiya, Hyogo 663-8501, Japan
| | - Yoshitaka Oku
- Department of Physiology, Faculty of Medicine, Hyogo Medical University, Nishinomiya, Hyogo 663-8501, Japan
| | - Ikuko Yao
- Biomedical Chemistry major, Graduate School of Science and Technology, Kwansei Gakuin University, Sanda, Hyogo 669-1330, Japan
| | - Kohei Koga
- Department of Neurophysiology, Faculty of Medicine, Hyogo Medical University, Nishinomiya, Hyogo 663-8501, Japan.
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27
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Li C, Zhang X, Chen P, Zhou K, Yu J, Wu G, Xiang D, Jiang H, Wang M, Liu Q. Short-term synaptic plasticity in emerging devices for neuromorphic computing. iScience 2023; 26:106315. [PMID: 36950108 PMCID: PMC10025973 DOI: 10.1016/j.isci.2023.106315] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/06/2023] Open
Abstract
Neuromorphic computing is a promising computing paradigm toward building next-generation artificial intelligence machines, in which diverse types of synaptic plasticity play an active role in information processing. Compared to long-term plasticity (LTP) forming the foundation of learning and memory, short-term plasticity (STP) is essential for critical computational functions. So far, the practical applications of LTP have been widely investigated, whereas the implementation of STP in hardware is still elusive. Here, we review the development of STP by bridging the physics in emerging devices and biological behaviors. We explore the computational functions of various STP in biology and review their recent progress. Finally, we discuss the main challenges of introducing STP into synaptic devices and offer the potential approaches to utilize STP to enrich systems' capabilities. This review is expected to provide prospective ideas for implementing STP in emerging devices and may promote the construction of high-level neuromorphic machines.
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Affiliation(s)
- Chao Li
- State Key Laboratory of Integrated Chip and System, Frontier Institute of Chip and System, Fudan University, Shanghai 200433, China
- Key Laboratory of Microelectronics Device & Integrated Technology, Institute of Microelectronics of Chinese Academy of Sciences, Beijing 100029, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Xumeng Zhang
- State Key Laboratory of Integrated Chip and System, Frontier Institute of Chip and System, Fudan University, Shanghai 200433, China
- Zhangjiang Fudan International Innovation Center, Fudan University, Shanghai 200433, China
- Shanghai Qi Zhi Institute, Shanghai 200232, China
| | - Pei Chen
- State Key Laboratory of Integrated Chip and System, Frontier Institute of Chip and System, Fudan University, Shanghai 200433, China
| | - Keji Zhou
- State Key Laboratory of Integrated Chip and System, Frontier Institute of Chip and System, Fudan University, Shanghai 200433, China
- Zhangjiang Fudan International Innovation Center, Fudan University, Shanghai 200433, China
- Shanghai Qi Zhi Institute, Shanghai 200232, China
| | - Jie Yu
- State Key Laboratory of Integrated Chip and System, Frontier Institute of Chip and System, Fudan University, Shanghai 200433, China
- Zhangjiang Fudan International Innovation Center, Fudan University, Shanghai 200433, China
| | - Guangjian Wu
- State Key Laboratory of Integrated Chip and System, Frontier Institute of Chip and System, Fudan University, Shanghai 200433, China
- Zhangjiang Fudan International Innovation Center, Fudan University, Shanghai 200433, China
- Shanghai Qi Zhi Institute, Shanghai 200232, China
| | - Du Xiang
- State Key Laboratory of Integrated Chip and System, Frontier Institute of Chip and System, Fudan University, Shanghai 200433, China
- Zhangjiang Fudan International Innovation Center, Fudan University, Shanghai 200433, China
- Shanghai Qi Zhi Institute, Shanghai 200232, China
| | - Hao Jiang
- State Key Laboratory of Integrated Chip and System, Frontier Institute of Chip and System, Fudan University, Shanghai 200433, China
- Zhangjiang Fudan International Innovation Center, Fudan University, Shanghai 200433, China
- Shanghai Qi Zhi Institute, Shanghai 200232, China
| | - Ming Wang
- State Key Laboratory of Integrated Chip and System, Frontier Institute of Chip and System, Fudan University, Shanghai 200433, China
- Zhangjiang Fudan International Innovation Center, Fudan University, Shanghai 200433, China
- Shanghai Qi Zhi Institute, Shanghai 200232, China
| | - Qi Liu
- State Key Laboratory of Integrated Chip and System, Frontier Institute of Chip and System, Fudan University, Shanghai 200433, China
- Zhangjiang Fudan International Innovation Center, Fudan University, Shanghai 200433, China
- Shanghai Qi Zhi Institute, Shanghai 200232, China
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28
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Poon CH, Liu Y, Pak S, Zhao RC, Aquili L, Tipoe GL, Leung GKK, Chan YS, Yang S, Fung ML, Wu EX, Lim LW. Prelimbic Cortical Stimulation with L-methionine Enhances Cognition through Hippocampal DNA Methylation and Neuroplasticity Mechanisms. Aging Dis 2023; 14:112-135. [PMID: 36818556 PMCID: PMC9937711 DOI: 10.14336/ad.2022.0706] [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: 05/22/2022] [Accepted: 07/06/2022] [Indexed: 11/18/2022] Open
Abstract
Declining global DNA methylation and cognitive impairment are reported to occur in the normal aging process. It is not known if DNA methylation plays a role in the efficacy of memory-enhancing therapies. In this study, aged animals were administered prelimbic cortical deep brain stimulation (PrL DBS) and/or L-methionine (MET) treatment. We found that PrL DBS and MET (MET-PrL DBS) co-administration resulted in hippocampal-dependent spatial memory enhancements in aged animals. Molecular data suggested MET-PrL DBS induced DNA methyltransferase DNMT3a-dependent methylation, robust synergistic upregulation of neuroplasticity-related genes, and simultaneous inhibition of the memory-suppressing gene calcineurin in the hippocampus. We further found that MET-PrL DBS also activated the PKA-CaMKIIα-BDNF pathway, increased hippocampal neurogenesis, and enhanced dopaminergic and serotonergic neurotransmission. We next inhibited the activity of DNA methyltransferase (DNMT) by RG108 infusion in the hippocampus of young animals to establish a causal relationship between DNMT activity and the effects of PrL DBS. Hippocampal DNMT inhibition in young animals was sufficient to recapitulate the behavioral deficits observed in aged animals and abolished the memory-enhancing and molecular effects of PrL DBS. Our findings implicate hippocampal DNMT as a therapeutic target for PrL DBS and pave way for the potential use of non-invasive neuromodulation modalities against dementia.
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Affiliation(s)
- Chi Him Poon
- School of Biomedical Sciences, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong SAR, China.
| | - Yanzhi Liu
- School of Biomedical Sciences, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong SAR, China.
| | - Sojeong Pak
- Department of Neuroscience, City University of Hong Kong, Kowloon, Hong Kong, China.
| | | | - Luca Aquili
- School of Biomedical Sciences, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong SAR, China.,College of Science, Health, Engineering and Education, Discipline of Psychology, Murdoch University, Perth, Australia.
| | - George Lim Tipoe
- School of Biomedical Sciences, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong SAR, China.
| | - Gilberto Ka-Kit Leung
- Department of Surgery, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, China.
| | - Ying-Shing Chan
- School of Biomedical Sciences, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong SAR, China.
| | - Sungchil Yang
- Department of Neuroscience, City University of Hong Kong, Kowloon, Hong Kong, China.
| | - Man-Lung Fung
- School of Biomedical Sciences, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong SAR, China.
| | - Ed Xuekui Wu
- Department of Electrical and Electronic Engineering, The University of Hong Kong, Hong Kong, China.
| | - Lee Wei Lim
- School of Biomedical Sciences, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong SAR, China.,Correspondence should be addressed to: Dr. Lee Wei LIM, Neuromodulation Laboratory, School of Biomedical Sciences, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong SAR, China. .
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29
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FMRP activity and control of Csw/SHP2 translation regulate MAPK-dependent synaptic transmission. PLoS Biol 2023; 21:e3001969. [PMID: 36701299 PMCID: PMC9879533 DOI: 10.1371/journal.pbio.3001969] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2022] [Accepted: 12/16/2022] [Indexed: 01/27/2023] Open
Abstract
Noonan syndrome (NS) and NS with multiple lentigines (NSML) cognitive dysfunction are linked to SH2 domain-containing protein tyrosine phosphatase-2 (SHP2) gain-of-function (GoF) and loss-of-function (LoF), respectively. In Drosophila disease models, we find both SHP2 mutations from human patients and corkscrew (csw) homolog LoF/GoF elevate glutamatergic transmission. Cell-targeted RNAi and neurotransmitter release analyses reveal a presynaptic requirement. Consistently, all mutants exhibit reduced synaptic depression during high-frequency stimulation. Both LoF and GoF mutants also show impaired synaptic plasticity, including reduced facilitation, augmentation, and post-tetanic potentiation. NS/NSML diseases are characterized by elevated MAPK/ERK signaling, and drugs suppressing this signaling restore normal neurotransmission in mutants. Fragile X syndrome (FXS) is likewise characterized by elevated MAPK/ERK signaling. Fragile X Mental Retardation Protein (FMRP) binds csw mRNA and neuronal Csw protein is elevated in Drosophila fragile X mental retardation 1 (dfmr1) nulls. Moreover, phosphorylated ERK (pERK) is increased in dfmr1 and csw null presynaptic boutons. We find presynaptic pERK activation in response to stimulation is reduced in dfmr1 and csw nulls. Trans-heterozygous csw/+; dfmr1/+ recapitulate elevated presynaptic pERK activation and function, showing FMRP and Csw/SHP2 act within the same signaling pathway. Thus, a FMRP and SHP2 MAPK/ERK regulative mechanism controls basal and activity-dependent neurotransmission strength.
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30
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Buszka A, Pytyś A, Colvin D, Włodarczyk J, Wójtowicz T. S-Palmitoylation of Synaptic Proteins in Neuronal Plasticity in Normal and Pathological Brains. Cells 2023; 12:cells12030387. [PMID: 36766729 PMCID: PMC9913408 DOI: 10.3390/cells12030387] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2022] [Revised: 01/08/2023] [Accepted: 01/17/2023] [Indexed: 01/24/2023] Open
Abstract
Protein lipidation is a common post-translational modification of proteins that plays an important role in human physiology and pathology. One form of protein lipidation, S-palmitoylation, involves the addition of a 16-carbon fatty acid (palmitate) onto proteins. This reversible modification may affect the regulation of protein trafficking and stability in membranes. From multiple recent experimental studies, a picture emerges whereby protein S-palmitoylation is a ubiquitous yet discrete molecular switch enabling the expansion of protein functions and subcellular localization in minutes to hours. Neural tissue is particularly rich in proteins that are regulated by S-palmitoylation. A surge of novel methods of detection of protein lipidation at high resolution allowed us to get better insights into the roles of protein palmitoylation in brain physiology and pathophysiology. In this review, we specifically discuss experimental work devoted to understanding the impact of protein palmitoylation on functional changes in the excitatory and inhibitory synapses associated with neuronal activity and neuronal plasticity. The accumulated evidence also implies a crucial role of S-palmitoylation in learning and memory, and brain disorders associated with impaired cognitive functions.
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Jetti SK, Crane AB, Akbergenova Y, Aponte-Santiago NA, Cunningham KL, Whittaker CA, Littleton JT. Molecular Logic of Synaptic Diversity Between Drosophila Tonic and Phasic Motoneurons. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.01.17.524447. [PMID: 36711745 PMCID: PMC9882338 DOI: 10.1101/2023.01.17.524447] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Although neuronal subtypes display unique synaptic organization and function, the underlying transcriptional differences that establish these features is poorly understood. To identify molecular pathways that contribute to synaptic diversity, single neuron PatchSeq RNA profiling was performed on Drosophila tonic and phasic glutamatergic motoneurons. Tonic motoneurons form weaker facilitating synapses onto single muscles, while phasic motoneurons form stronger depressing synapses onto multiple muscles. Super-resolution microscopy and in vivo imaging demonstrated synaptic active zones in phasic motoneurons are more compact and display enhanced Ca 2+ influx compared to their tonic counterparts. Genetic analysis identified unique synaptic properties that mapped onto gene expression differences for several cellular pathways, including distinct signaling ligands, post-translational modifications and intracellular Ca 2+ buffers. These findings provide insights into how unique transcriptomes drive functional and morphological differences between neuronal subtypes.
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Affiliation(s)
- Suresh K Jetti
- The Picower Institute for Learning and Memory, Department of Biology and Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, Massachusetts, 02139
| | - Andrés B Crane
- The Picower Institute for Learning and Memory, Department of Biology and Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, Massachusetts, 02139
| | - Yulia Akbergenova
- The Picower Institute for Learning and Memory, Department of Biology and Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, Massachusetts, 02139
| | - Nicole A Aponte-Santiago
- The Picower Institute for Learning and Memory, Department of Biology and Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, Massachusetts, 02139
| | - Karen L Cunningham
- The Picower Institute for Learning and Memory, Department of Biology and Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, Massachusetts, 02139
| | - Charles A Whittaker
- Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, Massachusetts, 02139
| | - J Troy Littleton
- The Picower Institute for Learning and Memory, Department of Biology and Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, Massachusetts, 02139
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Flores-Muñoz C, García-Rojas F, Pérez MA, Santander O, Mery E, Ordenes S, Illanes-González J, López-Espíndola D, González-Jamett AM, Fuenzalida M, Martínez AD, Ardiles ÁO. The Long-Term Pannexin 1 Ablation Produces Structural and Functional Modifications in Hippocampal Neurons. Cells 2022; 11:cells11223646. [PMID: 36429074 PMCID: PMC9688914 DOI: 10.3390/cells11223646] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2022] [Revised: 10/29/2022] [Accepted: 11/10/2022] [Indexed: 11/19/2022] Open
Abstract
Enhanced activity and overexpression of Pannexin 1 (Panx1) channels contribute to neuronal pathologies such as epilepsy and Alzheimer's disease (AD). The Panx1 channel ablation alters the hippocampus's glutamatergic neurotransmission, synaptic plasticity, and memory flexibility. Nevertheless, Panx1-knockout (Panx1-KO) mice still retain the ability to learn, suggesting that compensatory mechanisms stabilize their neuronal activity. Here, we show that the absence of Panx1 in the adult brain promotes a series of structural and functional modifications in the Panx1-KO hippocampal synapses, preserving spontaneous activity. Compared to the wild-type (WT) condition, the adult hippocampal neurons of Panx1-KO mice exhibit enhanced excitability, a more complex dendritic branching, enhanced spine maturation, and an increased proportion of multiple synaptic contacts. These modifications seem to rely on the actin-cytoskeleton dynamics as an increase in the actin polymerization and an imbalance between the Rac1 and the RhoA GTPase activities were observed in Panx1-KO brain tissues. Our findings highlight a novel interaction between Panx1 channels, actin, and Rho GTPases, which appear to be relevant for synapse stability.
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Affiliation(s)
- Carolina Flores-Muñoz
- Centro Interdisciplinario de Neurociencia de Valparaíso, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso 2360102, Chile
- Centro de Neurología Traslacional, Facultad de Medicina, Universidad de Valparaíso, Valparaíso 2341386, Chile
- Programa de Doctorado en Ciencias, Mención Neurociencia, Universidad de Valparaíso, Valparaíso 2340000, Chile
| | - Francisca García-Rojas
- Programa de Doctorado en Ciencias, Mención Neurociencia, Universidad de Valparaíso, Valparaíso 2340000, Chile
- Centro de Neurobiología y Fisiopatología integrativa, CENFI, Instituto de Fisiología, Universidad de Valparaíso, Valparaíso 2340000, Chile
| | - Miguel A. Pérez
- Centro de Neurobiología y Fisiopatología integrativa, CENFI, Instituto de Fisiología, Universidad de Valparaíso, Valparaíso 2340000, Chile
- Escuela de Ciencias de la Salud, Universidad de Viña del Mar, Viña del Mar 2572007, Chile
| | - Odra Santander
- Programa de Doctorado en Ciencias, Mención Neurociencia, Universidad de Valparaíso, Valparaíso 2340000, Chile
- Centro de Neurobiología y Fisiopatología integrativa, CENFI, Instituto de Fisiología, Universidad de Valparaíso, Valparaíso 2340000, Chile
| | - Elena Mery
- Centro Interdisciplinario de Neurociencia de Valparaíso, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso 2360102, Chile
- Centro de Neurología Traslacional, Facultad de Medicina, Universidad de Valparaíso, Valparaíso 2341386, Chile
| | - Stefany Ordenes
- Centro Interdisciplinario de Neurociencia de Valparaíso, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso 2360102, Chile
- Centro de Neurología Traslacional, Facultad de Medicina, Universidad de Valparaíso, Valparaíso 2341386, Chile
- Programa de Doctorado en Ciencias, Mención Neurociencia, Universidad de Valparaíso, Valparaíso 2340000, Chile
| | - Javiera Illanes-González
- Centro Interdisciplinario de Neurociencia de Valparaíso, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso 2360102, Chile
- Centro de Neurología Traslacional, Facultad de Medicina, Universidad de Valparaíso, Valparaíso 2341386, Chile
- Programa de Doctorado en Ciencias, Mención Neurociencia, Universidad de Valparaíso, Valparaíso 2340000, Chile
| | - Daniela López-Espíndola
- Escuela de Tecnología Médica, Facultad de Medicina, Universidad de Valparaíso, Valparaíso 2529002, Chile
- Centro de Investigaciones Biomédicas, Escuela de Medicina, Facultad de Medicina, Universidad de Valparaíso, Viña del Mar 2529002, Chile
| | - Arlek M. González-Jamett
- Centro Interdisciplinario de Neurociencia de Valparaíso, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso 2360102, Chile
- Escuela de Química y Farmacia, Facultad de Farmacia, Universidad de Valparaíso, Valparaíso 2360102, Chile
| | - Marco Fuenzalida
- Centro de Neurobiología y Fisiopatología integrativa, CENFI, Instituto de Fisiología, Universidad de Valparaíso, Valparaíso 2340000, Chile
- Correspondence: (M.F.); (A.D.M.); (Á.O.A.)
| | - Agustín D. Martínez
- Centro Interdisciplinario de Neurociencia de Valparaíso, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso 2360102, Chile
- Correspondence: (M.F.); (A.D.M.); (Á.O.A.)
| | - Álvaro O. Ardiles
- Centro Interdisciplinario de Neurociencia de Valparaíso, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso 2360102, Chile
- Centro de Neurología Traslacional, Facultad de Medicina, Universidad de Valparaíso, Valparaíso 2341386, Chile
- Centro Interdisciplinario de estudios en salud, Escuela de Medicina, Facultad de Medicina, Universidad de Valparaíso, Viña del Mar 2572007, Chile
- Correspondence: (M.F.); (A.D.M.); (Á.O.A.)
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Bhattacharya D, Bartley AF, Li Q, Dobrunz LE. Bicuculline restores frequency-dependent hippocampal I/E ratio and circuit function in PGC-1ɑ null mice. Neurosci Res 2022; 184:9-18. [PMID: 35842011 PMCID: PMC10865982 DOI: 10.1016/j.neures.2022.07.003] [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: 06/03/2022] [Revised: 06/22/2022] [Accepted: 07/12/2022] [Indexed: 10/31/2022]
Abstract
Altered inhibition/excitation (I/E) balance contributes to various brain disorders. Dysfunctional GABAergic interneurons enhance or reduce inhibition, resulting in I/E imbalances. Differences in short-term plasticity between excitation and inhibition cause frequency-dependence of the I/E ratio, which can be altered by GABAergic dysfunction. However, it is unknown whether I/E imbalances can be rescued pharmacologically using a single dose when the imbalance magnitude is frequency-dependent. Loss of PGC-1α (peroxisome proliferator activated receptor γ coactivator 1α) causes transcriptional dysregulation in hippocampal GABAergic interneurons. PGC-1α-/- slices have enhanced baseline inhibition onto CA1 pyramidal cells, causing increased I/E ratio and impaired circuit function. High frequency stimulation reduces the I/E ratio and recovers circuit function in PGC-1α-/- slices. Here we tested if using a low dose of bicuculline that can restore baseline I/E ratio can also rescue the frequency-dependent I/E imbalances in these mice. Remarkably, bicuculline did not reduce the I/E ratio below that of wild type during high frequency stimulation. Interestingly, bicuculline enhanced the paired-pulse ratio (PPR) of disynaptic inhibition without changing the monosynaptic inhibition PPR, suggesting that bicuculline modifies interneuron recruitment and not GABA release. Bicuculline improved CA1 output in PGC-1α-/- slices, enhancing EPSP-spike coupling to wild type levels at high and low frequencies. Our results show that it is possible to rescue frequency-dependent I/E imbalances in an animal model of transcriptional dysregulation with a single treatment.
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Affiliation(s)
- Dwipayan Bhattacharya
- Department of Neurobiology, Civitan International Research Center, and Evelyn F. McKnight Brain Institute, University of Alabama at Birmingham, 1825 University Blvd., Birmingham, AL, United States
| | - Aundrea F Bartley
- Department of Neurobiology, Civitan International Research Center, and Evelyn F. McKnight Brain Institute, University of Alabama at Birmingham, 1825 University Blvd., Birmingham, AL, United States
| | - Qin Li
- Department of Neurobiology, Civitan International Research Center, and Evelyn F. McKnight Brain Institute, University of Alabama at Birmingham, 1825 University Blvd., Birmingham, AL, United States
| | - Lynn E Dobrunz
- Department of Neurobiology, Civitan International Research Center, and Evelyn F. McKnight Brain Institute, University of Alabama at Birmingham, 1825 University Blvd., Birmingham, AL, United States.
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Di Castro MA, Garofalo S, De Felice E, Meneghetti N, Di Pietro E, Mormino A, Mazzoni A, Caleo M, Maggi L, Limatola C. Environmental enrichment counteracts the effects of glioma in primary visual cortex. Neurobiol Dis 2022; 174:105894. [DOI: 10.1016/j.nbd.2022.105894] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2022] [Revised: 10/07/2022] [Accepted: 10/10/2022] [Indexed: 11/25/2022] Open
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Weingarten DJ, Shrestha A, Juda-Nelson K, Kissiwaa SA, Spruston E, Jackman SL. Fast resupply of synaptic vesicles requires synaptotagmin-3. Nature 2022; 611:320-325. [PMID: 36261524 DOI: 10.1038/s41586-022-05337-1] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2021] [Accepted: 09/12/2022] [Indexed: 01/09/2023]
Abstract
Sustained neuronal activity demands a rapid resupply of synaptic vesicles to maintain reliable synaptic transmission. Such vesicle replenishment is accelerated by submicromolar presynaptic Ca2+ signals by an as-yet unidentified high-affinity Ca2+ sensor1,2. Here we identify synaptotagmin-3 (SYT3)3,4 as that presynaptic high-affinity Ca2+ sensor, which drives vesicle replenishment and short-term synaptic plasticity. Synapses in Syt3 knockout mice exhibited enhanced short-term depression, and recovery from depression was slower and insensitive to presynaptic residual Ca2+. During sustained neuronal firing, SYT3 accelerated vesicle replenishment and increased the size of the readily releasable pool. SYT3 also mediated short-term facilitation under conditions of low release probability and promoted synaptic enhancement together with another high-affinity synaptotagmin, SYT7 (ref. 5). Biophysical modelling predicted that SYT3 mediates both replenishment and facilitation by promoting the transition of loosely docked vesicles to tightly docked, primed states. Our results reveal a crucial role for presynaptic SYT3 in the maintenance of reliable high-frequency synaptic transmission. Moreover, multiple forms of short-term plasticity may converge on a mechanism of reversible, Ca2+-dependent vesicle docking.
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Affiliation(s)
| | - Amita Shrestha
- Vollum Institute, Oregon Health and Science University, Portland, OR, USA
| | - Kessa Juda-Nelson
- Vollum Institute, Oregon Health and Science University, Portland, OR, USA
| | - Sarah A Kissiwaa
- Vollum Institute, Oregon Health and Science University, Portland, OR, USA
| | - Evan Spruston
- Vollum Institute, Oregon Health and Science University, Portland, OR, USA
| | - Skyler L Jackman
- Vollum Institute, Oregon Health and Science University, Portland, OR, USA.
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36
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Midorikawa M. Developmental and activity-dependent modulation of coupling distance between release site and Ca2+ channel. Front Cell Neurosci 2022; 16:1037721. [DOI: 10.3389/fncel.2022.1037721] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2022] [Accepted: 10/11/2022] [Indexed: 11/13/2022] Open
Abstract
Synapses are junctions between a presynaptic neuron and a postsynaptic cell specialized for fast and precise information transfer. The presynaptic terminal secretes neurotransmitters via exocytosis of synaptic vesicles. Exocytosis is a tightly regulated reaction that occurs within a millisecond of the arrival of an action potential. One crucial parameter in determining the characteristics of the transmitter release kinetics is the coupling distance between the release site and the Ca2+ channel. Still, the technical limitations have hindered detailed analysis from addressing how the coupling distance is regulated depending on the development or activity of the synapse. However, recent technical advances in electrophysiology and imaging are unveiling their different configurations in different conditions. Here, I will summarize developmental- and activity-dependent changes in the coupling distances revealed by recent studies.
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37
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Whitt JL, Ewall G, Chakraborty D, Adegbesan A, Lee R, Kanold PO, Lee HK. Visual Deprivation Selectively Reduces Thalamic Reticular Nucleus-Mediated Inhibition of the Auditory Thalamus in Adults. J Neurosci 2022; 42:7921-7930. [PMID: 36261269 PMCID: PMC9617613 DOI: 10.1523/jneurosci.2032-21.2022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2021] [Revised: 08/19/2022] [Accepted: 08/24/2022] [Indexed: 11/21/2022] Open
Abstract
Sensory loss leads to widespread cross-modal plasticity across brain areas to allow the remaining senses to guide behavior. While multimodal sensory interactions are often attributed to higher-order sensory areas, cross-modal plasticity has been observed at the level of synaptic changes even across primary sensory cortices. In particular, vision loss leads to widespread circuit adaptation in the primary auditory cortex (A1) even in adults. Here we report using mice of both sexes in which cross-modal plasticity occurs even earlier in the sensory-processing pathway at the level of the thalamus in a modality-selective manner. A week of visual deprivation reduced inhibitory synaptic transmission from the thalamic reticular nucleus (TRN) to the primary auditory thalamus (MGBv) without changes to the primary visual thalamus (dLGN). The plasticity of TRN inhibition to MGBv was observed as a reduction in postsynaptic gain and short-term depression. There was no observable plasticity of the cortical feedback excitatory synaptic transmission from the primary visual cortex to dLGN or TRN and A1 to MGBv, which suggests that the visual deprivation-induced plasticity occurs predominantly at the level of thalamic inhibition. We provide evidence that visual deprivation-induced change in the short-term depression of TRN inhibition to MGBv involves endocannabinoid CB1 receptors. TRN inhibition is considered critical for sensory gating, selective attention, and multimodal performances; hence, its plasticity has implications for sensory processing. Our results suggest that selective disinhibition and altered short-term dynamics of TRN inhibition in the spared thalamic nucleus support cross-modal plasticity in the adult brain.SIGNIFICANCE STATEMENT Losing vision triggers adaptation of the brain to enhance the processing of the remaining senses, which can be observed as better auditory performance in blind subjects. We previously found that depriving vision of adult rodents produces widespread circuit reorganization in the primary auditory cortex and enhances auditory processing at a neural level. Here we report that visual deprivation-induced plasticity in adults occurs much earlier in the auditory pathway, at the level of thalamic inhibition. Sensory processing is largely gated at the level of the thalamus via strong cortical feedback inhibition mediated through the thalamic reticular nucleus (TRN). We found that TRN inhibition of the auditory thalamus is selectively reduced by visual deprivation, thus playing a role in adult cross-modal plasticity.
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Affiliation(s)
- Jessica L Whitt
- Zanvyl-Krieger Mind/Brain Institute, Johns Hopkins University, Baltimore, Maryland 21218
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205
| | - Gabrielle Ewall
- Zanvyl-Krieger Mind/Brain Institute, Johns Hopkins University, Baltimore, Maryland 21218
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205
| | - Darpan Chakraborty
- Zanvyl-Krieger Mind/Brain Institute, Johns Hopkins University, Baltimore, Maryland 21218
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205
| | - Ayorinde Adegbesan
- Zanvyl-Krieger Mind/Brain Institute, Johns Hopkins University, Baltimore, Maryland 21218
| | - Rachel Lee
- Zanvyl-Krieger Mind/Brain Institute, Johns Hopkins University, Baltimore, Maryland 21218
| | - Patrick O Kanold
- Department of Biomedical Engineering, Whiting School of Engineering and Johns Hopkins University School of Medicine, Baltimore, Maryland 21205
- Kavli Neuroscience Discovery Institute, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205
| | - Hey-Kyoung Lee
- Zanvyl-Krieger Mind/Brain Institute, Johns Hopkins University, Baltimore, Maryland 21218
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205
- Kavli Neuroscience Discovery Institute, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205
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Liu X, Hua F, Yang D, Lin Y, Zhang L, Ying J, Sheng H, Wang X. Roles of neuroligins in central nervous system development: focus on glial neuroligins and neuron neuroligins. Lab Invest 2022; 20:418. [PMID: 36088343 PMCID: PMC9463862 DOI: 10.1186/s12967-022-03625-y] [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: 07/25/2022] [Accepted: 09/01/2022] [Indexed: 11/10/2022]
Abstract
Neuroligins are postsynaptic cell adhesion molecules that are relevant to many neurodevelopmental disorders. They are differentially enriched at the postsynapse and interact with their presynaptic ligands, neurexins, whose differential binding to neuroligins has been shown to regulate synaptogenesis, transmission, and other synaptic properties. The proper functioning of functional networks in the brain depends on the proper connection between neuronal synapses. Impaired synaptogenesis or synaptic transmission results in synaptic dysfunction, and these synaptic pathologies are the basis for many neurodevelopmental disorders. Deletions or mutations in the neuroligins genes have been found in patients with both autism and schizophrenia. It is because of the important role of neuroligins in synaptic connectivity and synaptic dysfunction that studies on neuroligins in the past have mainly focused on their expression in neurons. As studies on the expression of genes specific to various cells of the central nervous system deepened, neuroligins were found to be expressed in non-neuronal cells as well. In the central nervous system, glial cells are the most representative non-neuronal cells, which can also express neuroligins in large amounts, especially astrocytes and oligodendrocytes, and they are involved in the regulation of synaptic function, as are neuronal neuroligins. This review examines the mechanisms of neuron neuroligins and non-neuronal neuroligins in the central nervous system and also discusses the important role of neuroligins in the development of the central nervous system and neurodevelopmental disorders from the perspective of neuronal neuroligins and glial neuroligins.
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Rizo J, David G, Fealey ME, Jaczynska K. On the difficulties of characterizing weak protein interactions that are critical for neurotransmitter release. FEBS Open Bio 2022; 12:1912-1938. [PMID: 35986639 PMCID: PMC9623538 DOI: 10.1002/2211-5463.13473] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2022] [Revised: 08/09/2022] [Accepted: 08/18/2022] [Indexed: 01/25/2023] Open
Abstract
The mechanism of neurotransmitter release has been extensively characterized, showing that vesicle fusion is mediated by the SNARE complex formed by syntaxin-1, SNAP-25 and synaptobrevin. This complex is disassembled by N-ethylmaleimide sensitive factor (NSF) and SNAPs to recycle the SNAREs, whereas Munc18-1 and Munc13s organize SNARE complex assembly in an NSF-SNAP-resistant manner. Synaptotagmin-1 acts as the Ca2+ sensor that triggers exocytosis in a tight interplay with the SNAREs and complexins. Here, we review technical aspects associated with investigation of protein interactions underlying these steps, which is hindered because the release machinery is assembled between two membranes and is highly dynamic. Moreover, weak interactions, which are difficult to characterize, play key roles in neurotransmitter release, for instance by lowering energy barriers that need to be overcome in this highly regulated process. We illustrate the crucial role that structural biology has played in uncovering mechanisms underlying neurotransmitter release, but also discuss the importance of considering the limitations of the techniques used, including lessons learned from research in our lab and others. In particular, we emphasize: (a) the promiscuity of some protein sequences, including membrane-binding regions that can mediate irrelevant interactions with proteins in the absence of their native targets; (b) the need to ensure that weak interactions observed in crystal structures are biologically relevant; and (c) the limitations of isothermal titration calorimetry to analyze weak interactions. Finally, we stress that even studies that required re-interpretation often helped to move the field forward by improving our understanding of the system and providing testable hypotheses.
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Affiliation(s)
- Josep Rizo
- Department of BiophysicsUniversity of Texas Southwestern Medical CenterDallasTXUSA,Department of BiochemistryUniversity of Texas Southwestern Medical CenterDallasTXUSA,Department of PharmacologyUniversity of Texas Southwestern Medical CenterDallasTXUSA
| | - Guillaume David
- Department of BiophysicsUniversity of Texas Southwestern Medical CenterDallasTXUSA,Department of BiochemistryUniversity of Texas Southwestern Medical CenterDallasTXUSA,Department of PharmacologyUniversity of Texas Southwestern Medical CenterDallasTXUSA
| | - Michael E. Fealey
- Department of BiophysicsUniversity of Texas Southwestern Medical CenterDallasTXUSA,Department of BiochemistryUniversity of Texas Southwestern Medical CenterDallasTXUSA,Department of PharmacologyUniversity of Texas Southwestern Medical CenterDallasTXUSA
| | - Klaudia Jaczynska
- Department of BiophysicsUniversity of Texas Southwestern Medical CenterDallasTXUSA,Department of BiochemistryUniversity of Texas Southwestern Medical CenterDallasTXUSA,Department of PharmacologyUniversity of Texas Southwestern Medical CenterDallasTXUSA
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40
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Developmental depression-to-facilitation shift controls excitation-inhibition balance. Commun Biol 2022; 5:873. [PMID: 36008708 PMCID: PMC9411206 DOI: 10.1038/s42003-022-03801-2] [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: 02/15/2022] [Accepted: 08/04/2022] [Indexed: 11/25/2022] Open
Abstract
Changes in the short-term dynamics of excitatory synapses over development have been observed throughout cortex, but their purpose and consequences remain unclear. Here, we propose that developmental changes in synaptic dynamics buffer the effect of slow inhibitory long-term plasticity, allowing for continuously stable neural activity. Using computational modeling we demonstrate that early in development excitatory short-term depression quickly stabilises neural activity, even in the face of strong, unbalanced excitation. We introduce a model of the commonly observed developmental shift from depression to facilitation and show that neural activity remains stable throughout development, while inhibitory synaptic plasticity slowly balances excitation, consistent with experimental observations. Our model predicts changes in the input responses from phasic to phasic-and-tonic and more precise spike timings. We also observe a gradual emergence of short-lasting memory traces governed by short-term plasticity development. We conclude that the developmental depression-to-facilitation shift may control excitation-inhibition balance throughout development with important functional consequences. Using computational modelling this study proposes that the commonly observed depression-to-facilitation shift across development controls excitation-inhibition balance in the brain.
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A sequential two-step priming scheme reproduces diversity in synaptic strength and short-term plasticity. Proc Natl Acad Sci U S A 2022; 119:e2207987119. [PMID: 35969787 PMCID: PMC9407230 DOI: 10.1073/pnas.2207987119] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/05/2022] Open
Abstract
Central nervous system synapses are diverse in strength and plasticity. Short-term plasticity has traditionally been evaluated with models postulating a single pool of functionally homogeneous fusion-competent synaptic vesicles. Many observations are not easily explainable by such simple models. We established and experimentally validated a scheme of synaptic vesicle priming consisting of two sequential and reversible steps of release–machinery assembly. This sequential two-step priming scheme faithfully reproduced plasticity at a glutamatergic model synapse. The proposed priming and fusion scheme was consistent with the measured mean responses and with the experimentally observed heterogeneity between synapses. Vesicle fusion probability was found to be relatively uniform among synapses, while the priming equilibrium at rest of mature versus immature vesicle priming states differed greatly. Glutamatergic synapses display variable strength and diverse short-term plasticity (STP), even for a given type of connection. Using nonnegative tensor factorization and conventional state modeling, we demonstrate that a kinetic scheme consisting of two sequential and reversible steps of release–machinery assembly and a final step of synaptic vesicle (SV) fusion reproduces STP and its diversity among synapses. Analyzing transmission at the calyx of Held synapses reveals that differences in synaptic strength and STP are not primarily caused by variable fusion probability (pfusion) but are determined by the fraction of docked synaptic vesicles equipped with a mature release machinery. Our simulations show that traditional quantal analysis methods do not necessarily report pfusion of SVs with a mature release machinery but reflect both pfusion and the distribution between mature and immature priming states at rest. Thus, the approach holds promise for a better mechanistic dissection of the roles of presynaptic proteins in the sequence of SV docking, two-step priming, and fusion. It suggests a mechanism for activity-induced redistribution of synaptic efficacy.
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Hendricks EL, Smith IR, Prates B, Barmaleki F, Liebl FLW. The CD63 homologs, Tsp42Ee and Tsp42Eg, restrict endocytosis and promote neurotransmission through differential regulation of synaptic vesicle pools. Front Cell Neurosci 2022; 16:957232. [PMID: 36072568 PMCID: PMC9441712 DOI: 10.3389/fncel.2022.957232] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2022] [Accepted: 08/04/2022] [Indexed: 11/30/2022] Open
Abstract
The Tetraspanin (Tsp), CD63, is a transmembrane component of late endosomes and facilitates vesicular trafficking through endosomal pathways. Despite being widely expressed in the human brain and localized to late endosomes, CD63's role in regulating endo- and exocytic cycling at the synapse has not been investigated. Synaptic vesicle pools are highly dynamic and disruptions in the mobilization and replenishment of these vesicle pools have adverse neuronal effects. We find that the CD63 homologs, Tsp42Ee and Tsp42Eg, are expressed at the Drosophila neuromuscular junction to regulate synaptic vesicle pools through both shared and unique mechanisms. Tsp42Ee and Tsp42Eg negatively regulate endocytosis and positively regulate neurotransmitter release. Both tsp mutants show impaired locomotion, reduced miniature endplate junctional current frequencies, and increased endocytosis. Expression of human CD63 in Drosophila neurons leads to impaired endocytosis suggesting the role of Tsps in endocytosis is conserved. We further show that Tsps influence the synaptic cytoskeleton and membrane composition by regulating Futsch loop formation and synaptic levels of SCAR and PI(4,5)P2. Finally, Tsp42Ee and Tsp42Eg influence the synaptic localization of several vesicle-associated proteins including Synapsin, Synaptotagmin, and Cysteine String Protein. Together, our results present a novel function for Tsps in the regulation of vesicle pools and provide insight into the molecular mechanisms of Tsp-related synaptic dysfunction.
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Affiliation(s)
| | | | | | | | - Faith L. W. Liebl
- Department of Biological Sciences, Southern Illinois University Edwardsville, Edwardsville, IL, United States
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43
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Xue X, Buccino AP, Saseendran Kumar S, Hierlemann A, Bartram J. Inferring monosynaptic connections from paired dendritic spine Ca 2+imaging and large-scale recording of extracellular spiking. J Neural Eng 2022; 19. [PMID: 35931040 DOI: 10.1088/1741-2552/ac8765] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2022] [Accepted: 08/05/2022] [Indexed: 11/12/2022]
Abstract
Techniques to identify monosynaptic connections between neurons have been vital for neuroscience research, facilitating important advancements concerning network topology, synaptic plasticity, and synaptic integration, among others. Here, we introduce a novel approach to identify and monitor monosynaptic connections using high-resolution dendritic spine Ca2+imaging combined with simultaneous large-scale recording of extracellular electrical activity by means of high-density microelectrode arrays (HD-MEAs). We introduce an easily adoptable analysis pipeline that associates the imaged spine with its presynaptic unit and test it onin vitrorecordings. The method is further validated and optimized by simulating synaptically-evoked spine Ca2+transients based on measured spike trains in order to obtain simulated ground-truth connections. The proposed approach offers unique advantages asi) it can be used to identify monosynaptic connections with an accurate localization of the synapse within the dendritic tree,ii) it provides precise information of presynaptic spiking, andiii) postsynaptic spine Ca2+signals and, finally,iv) the non-invasive nature of the proposed method allows for long-term measurements. The analysis toolkit together with the rich data sets that were acquired are made publicly available for further exploration by the research community.
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Affiliation(s)
- Xiaohan Xue
- D-BSSE, ETH Zürich, Mattenstrasse 26, Basel, 4058, SWITZERLAND
| | | | | | | | - Julian Bartram
- D-BSSE, ETH Zürich, Mattenstrasse 26, Basel, 4058, SWITZERLAND
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44
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Fieblinger T, Perez-Alvarez A, Lamothe-Molina PJ, Gee CE, Oertner TG. Presynaptic cGMP sets synaptic strength in the striatum and is important for motor learning. EMBO Rep 2022; 23:e54361. [PMID: 35735260 PMCID: PMC9346481 DOI: 10.15252/embr.202154361] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2021] [Revised: 05/30/2022] [Accepted: 06/01/2022] [Indexed: 12/02/2022] Open
Abstract
The striatum is a subcortical brain region responsible for the initiation and termination of voluntary movements. Striatal spiny projection neurons receive major excitatory synaptic input from neocortex and thalamus, and cyclic nucleotides have long been known to play important roles in striatal function. Yet, the precise mechanism of action is unclear. Here, we combine optogenetic stimulation, 2‐photon imaging, and genetically encoded scavengers to dissect the regulation of striatal synapses in mice. Our data show that excitatory striatal inputs are tonically depressed by phosphodiesterases (PDEs), in particular PDE1. Blocking PDE activity boosts presynaptic calcium entry and glutamate release, leading to strongly increased synaptic transmission. Although PDE1 degrades both cAMP and cGMP, we uncover that the concentration of cGMP, not cAMP, controls the gain of striatal inputs. Disturbing this gain control mechanism in vivo impairs motor skill learning in mice. The tight dependence of striatal excitatory synapses on PDE1 and cGMP offers a new perspective on the molecular mechanisms regulating striatal activity.
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Affiliation(s)
- Tim Fieblinger
- Institute for Synaptic Physiology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Alberto Perez-Alvarez
- Institute for Synaptic Physiology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.,Rapp OptoElectronic GmbH, Wedel, Germany
| | - Paul J Lamothe-Molina
- Institute for Synaptic Physiology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Christine E Gee
- Institute for Synaptic Physiology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Thomas G Oertner
- Institute for Synaptic Physiology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
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45
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Shetty MS, Ris L, Schindler RFR, Mizuno K, Fedele L, Giese KP, Brand T, Abel T. Mice Lacking the cAMP Effector Protein POPDC1 Show Enhanced Hippocampal Synaptic Plasticity. Cereb Cortex 2022; 32:3457-3471. [PMID: 34937090 PMCID: PMC9376866 DOI: 10.1093/cercor/bhab426] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2021] [Revised: 10/28/2021] [Accepted: 10/29/2021] [Indexed: 11/13/2022] Open
Abstract
Extensive research has uncovered diverse forms of synaptic plasticity and an array of molecular signaling mechanisms that act as positive or negative regulators. Specifically, cyclic 3',5'-cyclic adenosine monophosphate (cAMP)-dependent signaling pathways are crucially implicated in long-lasting synaptic plasticity. In this study, we examine the role of Popeye domain-containing protein 1 (POPDC1) (or blood vessel epicardial substance (BVES)), a cAMP effector protein, in modulating hippocampal synaptic plasticity. Unlike other cAMP effectors, such as protein kinase A (PKA) and exchange factor directly activated by cAMP, POPDC1 is membrane-bound and the sequence of the cAMP-binding cassette differs from canonical cAMP-binding domains, suggesting that POPDC1 may have an unique role in cAMP-mediated signaling. Our results show that Popdc1 is widely expressed in various brain regions including the hippocampus. Acute hippocampal slices from Popdc1 knockout (KO) mice exhibit PKA-dependent enhancement in CA1 long-term potentiation (LTP) in response to weaker stimulation paradigms, which in slices from wild-type mice induce only transient LTP. Loss of POPDC1, while not affecting basal transmission or input-specificity of LTP, results in altered response during high-frequency stimulation. Popdc1 KO mice also show enhanced forskolin-induced potentiation. Overall, these findings reveal POPDC1 as a novel negative regulator of hippocampal synaptic plasticity and, together with recent evidence for its interaction with phosphodiesterases (PDEs), suggest that POPDC1 is involved in modulating activity-dependent local cAMP-PKA-PDE signaling.
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Affiliation(s)
- Mahesh Shivarama Shetty
- Department of Neuroscience and Pharmacology, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA
- Iowa Neuroscience Institute, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA
| | - Laurence Ris
- Department of Neuroscience, University of Mons, Research Institute for Health Sciences and Technology, 7000 Mons, Belgium
| | | | - Keiko Mizuno
- Department of Neuroscience, King’s College, London SE5 9NU, UK
| | - Laura Fedele
- National Heart and Lung Institute, Imperial College London, London W12 ONN, UK
| | | | - Thomas Brand
- National Heart and Lung Institute, Imperial College London, London W12 ONN, UK
| | - Ted Abel
- Department of Neuroscience and Pharmacology, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA
- Iowa Neuroscience Institute, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA
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46
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Abstract
Optogenetic actuators enable highly precise spatiotemporal interrogation of biological processes at levels ranging from the subcellular to cells, circuits and behaving organisms. Although their application in neuroscience has traditionally focused on the control of spiking activity at the somatodendritic level, the scope of optogenetic modulators for direct manipulation of presynaptic functions is growing. Presynaptically localized opsins combined with light stimulation at the terminals allow light-mediated neurotransmitter release, presynaptic inhibition, induction of synaptic plasticity and specific manipulation of individual components of the presynaptic machinery. Here, we describe presynaptic applications of optogenetic tools in the context of the unique cell biology of axonal terminals, discuss their potential shortcomings and outline future directions for this rapidly developing research area.
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Burghard AL, Lee CM, Fabrizio-Stover EM, Oliver DL. Long-Duration Sound-Induced Facilitation Changes Population Activity in the Inferior Colliculus. Front Syst Neurosci 2022; 16:920642. [PMID: 35873097 PMCID: PMC9301083 DOI: 10.3389/fnsys.2022.920642] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2022] [Accepted: 06/03/2022] [Indexed: 11/13/2022] Open
Abstract
The inferior colliculus (IC) is at the midpoint of the auditory system and integrates virtually all information ascending from the auditory brainstem, organizes it, and transmits the results to the auditory forebrain. Its abundant, excitatory local connections are crucial for this task. This study describes a long duration sound (LDS)-induced potentiation in the IC that changes both subsequent tone-evoked responses and spontaneous activity. Afterdischarges, changes of spontaneous spiking following an LDS, were seen previously in single neurons. Here, we used multi-channel probes to record activity before and after a single, tetanic sound and describe the changes in a population of IC neurons. Following a 60 s narrowband-noise stimulation, a subset of recording channels (∼16%) showed afterdischarges. A facilitated response spike rate to tone pips following an LDS was also observed in ∼16% of channels. Both channels with an afterdischarge and channels with facilitated tone responses had higher firing rates in response to LDS, and the magnitude of the afterdischarges increased with increased responses to the LDS. This is the first study examining the effect of LDS stimulation on tone-evoked responses. This observed facilitation in vivo has similarities to post-tetanic potentiation in vitro as both manner of induction (strong stimulation for several seconds) as well as time-course of the facilitation (second to minute range) are comparable. Channels with and without facilitation appear to be intermixed and distributed widely in the central nucleus of IC, and this suggests a heretofore unknown property of some IC neurons or their circuits. Consequently, this sound-evoked facilitation may enhance the sound-evoked output of these neurons, while, simultaneously, most other IC neurons have reduced or unchanged output in response to the same stimulus.
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48
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Sandamirskaya Y, Kaboli M, Conradt J, Celikel T. Neuromorphic computing hardware and neural architectures for robotics. Sci Robot 2022; 7:eabl8419. [PMID: 35767646 DOI: 10.1126/scirobotics.abl8419] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Neuromorphic hardware enables fast and power-efficient neural network-based artificial intelligence that is well suited to solving robotic tasks. Neuromorphic algorithms can be further developed following neural computing principles and neural network architectures inspired by biological neural systems. In this Viewpoint, we provide an overview of recent insights from neuroscience that could enhance signal processing in artificial neural networks on chip and unlock innovative applications in robotics and autonomous intelligent systems. These insights uncover computing principles, primitives, and algorithms on different levels of abstraction and call for more research into the basis of neural computation and neuronally inspired computing hardware.
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Affiliation(s)
| | - Mohsen Kaboli
- BMW Group, Department of Research, New Technologies and Innovation, Munich, Germany.,Donders Institute for Brain, Cognition, and Behavior, Radboud University, Nijmegen, Netherlands
| | - Jorg Conradt
- Kungliga Tekniska Högskolan (KTH), School of Electrical Engineering and Computer Science, Stockholm, Sweden
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49
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Kusick GF, Ogunmowo TH, Watanabe S. Transient docking of synaptic vesicles: Implications and mechanisms. Curr Opin Neurobiol 2022; 74:102535. [PMID: 35398664 PMCID: PMC9167714 DOI: 10.1016/j.conb.2022.102535] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2022] [Revised: 02/19/2022] [Accepted: 03/06/2022] [Indexed: 02/03/2023]
Abstract
As synaptic vesicles fuse, they must continually be replaced with new docked, fusion-competent vesicles to sustain neurotransmission. It has long been appreciated that vesicles are recruited to docking sites in an activity-dependent manner. However, once entering the sites, vesicles were thought to be stably docked, awaiting calcium signals. Based on recent data from electrophysiology, electron microscopy, biochemistry, and computer simulations, a picture emerges in which vesicles can rapidly and reversibly transit between docking and undocking during activity. This "transient docking" can account for many aspects of synaptic physiology. In this review, we cover recent evidence for transient docking, physiological processes at the synapse that it may support, and progress on the underlying mechanisms. We also discuss an open question: what determines for how long and whether vesicles stay docked, or eventually undock?
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Affiliation(s)
- Grant F Kusick
- Department of Cell Biology, Johns Hopkins University, School of Medicine, 725 N Wolfe St., Baltimore, MD 21287, USA; Biochemistry, Cellular and Molecular Biology Graduate Program, Johns Hopkins University, School of Medicine, 1830 E. Monument St., Baltimore, MD 21287, USA. https://twitter.com/@ultrafastgrant
| | - Tyler H Ogunmowo
- Department of Cell Biology, Johns Hopkins University, School of Medicine, 725 N Wolfe St., Baltimore, MD 21287, USA; Biochemistry, Cellular and Molecular Biology Graduate Program, Johns Hopkins University, School of Medicine, 1830 E. Monument St., Baltimore, MD 21287, USA. https://twitter.com/@unculturedTy
| | - Shigeki Watanabe
- Department of Cell Biology, Johns Hopkins University, School of Medicine, 725 N Wolfe St., Baltimore, MD 21287, USA; Solomon H. Snyder Department of Neuroscience, Johns Hopkins University, School of Medicine, 725 N Wolfe St., Baltimore, MD 21287, USA.
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50
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Fieblinger T, Li C, Espa E, Cenci MA. Non-Apoptotic Caspase-3 Activation Mediates Early Synaptic Dysfunction of Indirect Pathway Neurons in the Parkinsonian Striatum. Int J Mol Sci 2022; 23:ijms23105470. [PMID: 35628278 PMCID: PMC9141690 DOI: 10.3390/ijms23105470] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2022] [Revised: 05/09/2022] [Accepted: 05/12/2022] [Indexed: 11/27/2022] Open
Abstract
Non-apoptotic caspase-3 activation is critically involved in dendritic spine loss and synaptic dysfunction in Alzheimer’s disease. It is, however, not known whether caspase-3 plays similar roles in other pathologies. Using a mouse model of clinically manifest Parkinson’s disease, we provide the first evidence that caspase-3 is transiently activated in the striatum shortly after the degeneration of nigrostriatal dopaminergic projections. This caspase-3 activation concurs with a rapid loss of dendritic spines and deficits in synaptic long-term depression (LTD) in striatal projection neurons forming the indirect pathway. Interestingly, systemic treatment with a caspase inhibitor prevents both the spine pruning and the deficit of indirect pathway LTD without interfering with the ongoing dopaminergic degeneration. Taken together, our data identify transient and non-apoptotic caspase activation as a critical event in the early plastic changes of indirect pathway neurons following dopamine denervation.
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Affiliation(s)
- Tim Fieblinger
- Basal Ganglia Pathophysiology Unit, Department of Experimental Medical Science, Lund University, 223 62 Lund, Sweden; (C.L.); (E.E.)
- University Medical Center Hamburg-Eppendorf, Institute for Synaptic Physiology, 20251 Hamburg, Germany
- Correspondence: (T.F.); (M.A.C.)
| | - Chang Li
- Basal Ganglia Pathophysiology Unit, Department of Experimental Medical Science, Lund University, 223 62 Lund, Sweden; (C.L.); (E.E.)
| | - Elena Espa
- Basal Ganglia Pathophysiology Unit, Department of Experimental Medical Science, Lund University, 223 62 Lund, Sweden; (C.L.); (E.E.)
| | - M. Angela Cenci
- Basal Ganglia Pathophysiology Unit, Department of Experimental Medical Science, Lund University, 223 62 Lund, Sweden; (C.L.); (E.E.)
- Correspondence: (T.F.); (M.A.C.)
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