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Rahimian R, Perlman K, Fakhfouri G, Mpai R, Richard VR, Hercher C, Penney L, Davoli MA, Nagy C, Zahedi RP, Borchers CH, Giros B, Turecki G, Mechawar N. Proteomic evidence of depression-associated astrocytic dysfunction in the human male olfactory bulb. Brain Behav Immun 2024; 122:110-121. [PMID: 39128570 DOI: 10.1016/j.bbi.2024.08.016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/16/2024] [Revised: 07/24/2024] [Accepted: 08/08/2024] [Indexed: 08/13/2024] Open
Abstract
The olfactory bulb (OB), a major structure of the limbic system, has been understudied in human investigations of psychopathologies such as depression. To explore more directly the molecular features of the OB in depression, a global comparative proteome analysis was carried out with human post-mortem OB samples from 11 males having suffered from depression and 12 healthy controls. We identified 188 differentially abundant proteins (with adjusted p < 0.05) between depressed cases and controls. Gene ontology and gene enrichment analyses suggested that these proteins are involved in biological processes including the complement and coagulation cascades. Cell type enrichment analysis displayed a significant reduction in several canonical astrocytic proteins in OBs from depressed patients. Furthermore, using RNA-fluorescence in-situ hybridization, we observed a decrease in the percentage of ALDH1L1+ cells expressing canonical astrocytic markers including ALDOC, NFIA, GJA1 (connexin 43) and SLC1A3 (EAAT1). These results are consistent with previous reports of downregulated astrocytic marker expression in other brain regions in depressed patients. We also conducted a comparative phosphoproteomic analysis of OB samples and found a dysregulation of proteins involved in neuronal and astrocytic functions. To determine whether OB astrocytic abnormalities is specific to humans, we also performed proteomics on the OB of socially defeated male mice, a commonly used model of depression. Cell-type specific analysis revealed that in socially defeated animals, the most striking OB protein alterations were associated with oligodendrocyte-lineage cells rather than with astrocytes, highlighting an important species difference. Overall, this study further highlights cerebral astrocytic abnormalities as a consistent feature of depression in humans.
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Affiliation(s)
- Reza Rahimian
- McGill Group for Suicide Studies, Douglas Mental Health University Institute, Verdun, QC, Canada; Department of Psychiatry, McGill University, Montreal, QC, Canada
| | - Kelly Perlman
- McGill Group for Suicide Studies, Douglas Mental Health University Institute, Verdun, QC, Canada; Integrated Program in Neuroscience, McGill University, Montreal, QC, Canada
| | - Gohar Fakhfouri
- Department of Psychiatry, Douglas Hospital, McGill University, Montreal, QC, Canada
| | - Refilwe Mpai
- McGill Group for Suicide Studies, Douglas Mental Health University Institute, Verdun, QC, Canada; Integrated Program in Neuroscience, McGill University, Montreal, QC, Canada
| | - Vincent R Richard
- Segal Cancer Proteomics Centre, Lady Davis Institute for Medical Research, Jewish General Hospital, McGill University, Montréal, QC, Canada
| | - Christa Hercher
- McGill Group for Suicide Studies, Douglas Mental Health University Institute, Verdun, QC, Canada; Integrated Program in Neuroscience, McGill University, Montreal, QC, Canada
| | - Lucy Penney
- Department of Psychiatry, Douglas Hospital, McGill University, Montreal, QC, Canada
| | - Maria Antonietta Davoli
- McGill Group for Suicide Studies, Douglas Mental Health University Institute, Verdun, QC, Canada; Department of Psychiatry, McGill University, Montreal, QC, Canada
| | - Corina Nagy
- McGill Group for Suicide Studies, Douglas Mental Health University Institute, Verdun, QC, Canada; Department of Psychiatry, McGill University, Montreal, QC, Canada; Integrated Program in Neuroscience, McGill University, Montreal, QC, Canada
| | - René P Zahedi
- Department of Internal Medicine, University of Manitoba, Winnipeg, MB, Canada; Manitoba Centre for Proteomics and Systems Biology, University of Manitoba, Winnipeg, MB, Canada; Department of Biochemistry and Medical Genetics, University of Manitoba, Winnipeg, MB, Canada; CancerCare Manitoba Research Institute, Winnipeg, MB, Canada
| | - Christoph H Borchers
- Segal Cancer Proteomics Centre, Lady Davis Institute for Medical Research, Jewish General Hospital, McGill University, Montréal, QC, Canada; Gerald Bronfman Department of Oncology, McGill University, Montréal, Québec, Canada; Department of Pathology, McGill University, Montréal, QC, Canada; Department of Experimental Medicine, McGill University, Montreal, QC, Canada
| | - Bruno Giros
- Department of Psychiatry, Douglas Hospital, McGill University, Montreal, QC, Canada
| | - Gustavo Turecki
- McGill Group for Suicide Studies, Douglas Mental Health University Institute, Verdun, QC, Canada; Department of Psychiatry, McGill University, Montreal, QC, Canada; Integrated Program in Neuroscience, McGill University, Montreal, QC, Canada
| | - Naguib Mechawar
- McGill Group for Suicide Studies, Douglas Mental Health University Institute, Verdun, QC, Canada; Department of Psychiatry, McGill University, Montreal, QC, Canada; Integrated Program in Neuroscience, McGill University, Montreal, QC, Canada.
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2
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Hu J, Zhang Y, Liu Q, Hu J, Ru Y, Zhang L, Xie L, Xue L. SARS-CoV-2 Inhibits Exo-Endocytosis and Enhances Short-Term Depression at a Central Synapse. Neurosci Bull 2024:10.1007/s12264-024-01293-0. [PMID: 39217213 DOI: 10.1007/s12264-024-01293-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2024] [Accepted: 05/31/2024] [Indexed: 09/04/2024] Open
Affiliation(s)
- Jiawei Hu
- State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Fudan University, Shanghai, 200438, China
- Department of Physiology and Neurobiology, School of Life Sciences, Fudan University, Shanghai, 200438, China
| | - Yuhan Zhang
- Department of Pulmonary and Critical Care Medicine, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, 200025, China
| | - Qingzhuo Liu
- Department of Physiology and Neurobiology, School of Life Sciences, Fudan University, Shanghai, 200438, China
| | - Jiaqi Hu
- State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Fudan University, Shanghai, 200438, China
- Department of Physiology and Neurobiology, School of Life Sciences, Fudan University, Shanghai, 200438, China
- Center for Rehabilitation Medicine, Department of Pain Management, Zhejiang Provincial People's Hospital, Affiliated People's Hospital, Hangzhou Medical College, Hangzhou, 310014, China
| | - Yichen Ru
- Department of Microbiology and Immunology, School of Life Sciences, Fudan University, Shanghai, 200438, China
| | - Lu Zhang
- Department of Microbiology and Immunology, School of Life Sciences, Fudan University, Shanghai, 200438, China
| | - Lixin Xie
- College of Pulmonary and Critical Care Medicine, 8th Medical Center of Chinese PLA General Hospital, Beijing, 100091, China.
| | - Lei Xue
- State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Fudan University, Shanghai, 200438, China.
- Department of Physiology and Neurobiology, School of Life Sciences, Fudan University, Shanghai, 200438, China.
- Research Institute of Intelligent Complex Systems, Fudan University, Shanghai, 200433, China.
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Bruentgens F, Moreno Velasquez L, Stumpf A, Parthier D, Breustedt J, Benfenati F, Milovanovic D, Schmitz D, Orlando M. The Lack of Synapsin Alters Presynaptic Plasticity at Hippocampal Mossy Fibers in Male Mice. eNeuro 2024; 11:ENEURO.0330-23.2024. [PMID: 38866497 PMCID: PMC11223178 DOI: 10.1523/eneuro.0330-23.2024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2023] [Revised: 05/17/2024] [Accepted: 05/20/2024] [Indexed: 06/14/2024] Open
Abstract
Synapsins are highly abundant presynaptic proteins that play a crucial role in neurotransmission and plasticity via the clustering of synaptic vesicles. The synapsin III isoform is usually downregulated after development, but in hippocampal mossy fiber boutons, it persists in adulthood. Mossy fiber boutons express presynaptic forms of short- and long-term plasticity, which are thought to underlie different forms of learning. Previous research on synapsins at this synapse focused on synapsin isoforms I and II. Thus, a complete picture regarding the role of synapsins in mossy fiber plasticity is still missing. Here, we investigated presynaptic plasticity at hippocampal mossy fiber boutons by combining electrophysiological field recordings and transmission electron microscopy in a mouse model lacking all synapsin isoforms. We found decreased short-term plasticity, i.e., decreased facilitation and post-tetanic potentiation, but increased long-term potentiation in male synapsin triple knock-out (KO) mice. At the ultrastructural level, we observed more dispersed vesicles and a higher density of active zones in mossy fiber boutons from KO animals. Our results indicate that all synapsin isoforms are required for fine regulation of short- and long-term presynaptic plasticity at the mossy fiber synapse.
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Affiliation(s)
- Felicitas Bruentgens
- Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin 10117, Germany
- NeuroCure Cluster of Excellence, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin 10117, Germany
| | - Laura Moreno Velasquez
- Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin 10117, Germany
- NeuroCure Cluster of Excellence, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin 10117, Germany
| | - Alexander Stumpf
- Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin 10117, Germany
- NeuroCure Cluster of Excellence, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin 10117, Germany
| | - Daniel Parthier
- Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin 10117, Germany
- NeuroCure Cluster of Excellence, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin 10117, Germany
- Max Delbrück Center for Molecular Medicine in the Helmholtz Association, Berlin 13125, Germany
| | - Jörg Breustedt
- Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin 10117, Germany
- NeuroCure Cluster of Excellence, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin 10117, Germany
| | - Fabio Benfenati
- Center for Synaptic Neuroscience and Technology, Istituto Italiano di Tecnologia, Genoa 16163, Italy
- IRCCS Ospedale Policlinico San Martino, Genoa 16132, Italy
| | - Dragomir Milovanovic
- Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin 10117, Germany
- German Center for Neurodegenerative Diseases (DZNE) Berlin, Berlin 10117, Germany
- Einstein Center for Neurosciences, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität Berlin, Berlin 10117, Germany
| | - Dietmar Schmitz
- Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin 10117, Germany
- NeuroCure Cluster of Excellence, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin 10117, Germany
- Max Delbrück Center for Molecular Medicine in the Helmholtz Association, Berlin 13125, Germany
- German Center for Neurodegenerative Diseases (DZNE) Berlin, Berlin 10117, Germany
- Einstein Center for Neurosciences, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität Berlin, Berlin 10117, Germany
- Bernstein Center for Computational Neuroscience, Humboldt-Universität zu Berlin, Berlin 10115, Germany
| | - Marta Orlando
- Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin 10117, Germany
- NeuroCure Cluster of Excellence, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin 10117, Germany
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Maity S, Huang Y, Kilgore MD, Thurmon AN, Vaasjo LO, Galazo MJ, Xu X, Cao J, Wang X, Ning B, Liu N, Fan J. Mapping dynamic molecular changes in hippocampal subregions after traumatic brain injury through spatial proteomics. Clin Proteomics 2024; 21:32. [PMID: 38735925 PMCID: PMC11089002 DOI: 10.1186/s12014-024-09485-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2024] [Accepted: 04/24/2024] [Indexed: 05/14/2024] Open
Abstract
BACKGROUND Traumatic brain injury (TBI) often results in diverse molecular responses, challenging traditional proteomic studies that measure average changes at tissue levels and fail to capture the complexity and heterogeneity of the affected tissues. Spatial proteomics offers a solution by providing insights into sub-region-specific alterations within tissues. This study focuses on the hippocampal sub-regions, analyzing proteomic expression profiles in mice at the acute (1 day) and subacute (7 days) phases of post-TBI to understand subregion-specific vulnerabilities and long-term consequences. METHODS Three mice brains were collected from each group, including Sham, 1-day post-TBI and 7-day post-TBI. Hippocampal subregions were extracted using Laser Microdissection (LMD) and subsequently analyzed by label-free quantitative proteomics. RESULTS The spatial analysis reveals region-specific protein abundance changes, highlighting the elevation of FN1, LGALS3BP, HP, and MUG-1 in the stratum moleculare (SM), suggesting potential immune cell enrichment post-TBI. Notably, established markers of chronic traumatic encephalopathy, IGHM and B2M, exhibit specific upregulation in the dentate gyrus bottom (DG2) independent of direct mechanical injury. Metabolic pathway analysis identifies disturbances in glucose and lipid metabolism, coupled with activated cholesterol synthesis pathways enriched in SM at 7-Day post-TBI and subsequently in deeper DG1 and DG2 suggesting a role in neurogenesis and the onset of recovery. Coordinated activation of neuroglia and microtubule dynamics in DG2 suggest recovery mechanisms in less affected regions. Cluster analysis revealed spatial variations post-TBI, indicative of dysregulated neuronal plasticity and neurogenesis and further predisposition to neurological disorders. TBI-induced protein upregulation (MUG-1, PZP, GFAP, TJP, STAT-1, and CD44) across hippocampal sub-regions indicates shared molecular responses and links to neurological disorders. Spatial variations were demonstrated by proteins dysregulated in both or either of the time-points exclusively in each subregion (ELAVL2, CLIC1 in PL, CD44 and MUG-1 in SM, and SHOC2, LGALS3 in DG). CONCLUSIONS Utilizing advanced spatial proteomics techniques, the study unveils the dynamic molecular responses in distinct hippocampal subregions post-TBI. It uncovers region-specific vulnerabilities and dysregulated neuronal processes, and potential recovery-related pathways that contribute to our understanding of TBI's neurological consequences and provides valuable insights for biomarker discovery and therapeutic targets.
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Affiliation(s)
- Sudipa Maity
- Center for Cellular and Molecular Diagnostics, Tulane University School of Medicine, New Orleans, LA, USA
- Department of Biochemistry and Molecular Biology, Tulane University School of Medicine, New Orleans, LA, USA
| | - Yuanyu Huang
- Center for Cellular and Molecular Diagnostics, Tulane University School of Medicine, New Orleans, LA, USA
- Department of Biochemistry and Molecular Biology, Tulane University School of Medicine, New Orleans, LA, USA
| | - Mitchell D Kilgore
- Clinical Neuroscience Research Center, Department of Neurosurgery and Neurology, Tulane University School of Medicine, New Orleans, LA, USA
| | - Abbigail N Thurmon
- Department of Cell and Molecular Biology, Tulane University, New Orleans, LA, USA
- Tulane Brain Institute, New Orleans, LA, USA
| | | | - Maria J Galazo
- Department of Cell and Molecular Biology, Tulane University, New Orleans, LA, USA
- Tulane Brain Institute, New Orleans, LA, USA
| | - Xiaojiang Xu
- Department of Pathology and Laboratory Medicine, Tulane University School of Medicine, New Orleans, LA, USA
| | - Jing Cao
- Department of Pathology, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Xiaoying Wang
- Clinical Neuroscience Research Center, Department of Neurosurgery and Neurology, Tulane University School of Medicine, New Orleans, LA, USA
| | - Bo Ning
- Center for Cellular and Molecular Diagnostics, Tulane University School of Medicine, New Orleans, LA, USA
- Department of Biochemistry and Molecular Biology, Tulane University School of Medicine, New Orleans, LA, USA
| | - Ning Liu
- Clinical Neuroscience Research Center, Department of Neurosurgery and Neurology, Tulane University School of Medicine, New Orleans, LA, USA.
- Tulane University Translational Sciences Institute, New Orleans, LA, USA.
| | - Jia Fan
- Center for Cellular and Molecular Diagnostics, Tulane University School of Medicine, New Orleans, LA, USA.
- Department of Biochemistry and Molecular Biology, Tulane University School of Medicine, New Orleans, LA, USA.
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5
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Leahy SN, Vita DJ, Broadie K. PTPN11/Corkscrew Activates Local Presynaptic Mapk Signaling to Regulate Synapsin, Synaptic Vesicle Pools, and Neurotransmission Strength, with a Dual Requirement in Neurons and Glia. J Neurosci 2024; 44:e1077232024. [PMID: 38471782 PMCID: PMC11044113 DOI: 10.1523/jneurosci.1077-23.2024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2023] [Revised: 03/01/2024] [Accepted: 03/05/2024] [Indexed: 03/14/2024] Open
Abstract
Cytoplasmic protein tyrosine phosphatase nonreceptor type 11 (PTPN11) and Drosophila homolog Corkscrew (Csw) regulate the mitogen-activated protein kinase (MAPK) pathway via a conserved autoinhibitory mechanism. Disease-causing loss-of-function (LoF) and gain-of-function (GoF) mutations both disrupt this autoinhibition to potentiate MAPK signaling. At the Drosophila neuromuscular junction glutamatergic synapse, LoF/GoF mutations elevate transmission strength and reduce activity-dependent synaptic depression. In both sexes of LoF/GoF mutations, the synaptic vesicles (SV)-colocalized synapsin phosphoprotein tether is highly elevated at rest, but quickly reduced with stimulation, suggesting a larger SV reserve pool with greatly heightened activity-dependent recruitment. Transmission electron microscopy of mutants reveals an elevated number of SVs clustered at the presynaptic active zones, suggesting that the increased vesicle availability is causative for the elevated neurotransmission. Direct neuron-targeted extracellular signal-regulated kinase (ERK) GoF phenocopies both increased local presynaptic MAPK/ERK signaling and synaptic transmission strength in mutants, confirming the presynaptic regulatory mechanism. Synapsin loss blocks this elevation in both presynaptic PTPN11 and ERK mutants. However, csw null mutants cannot be rescued by wild-type Csw in neurons: neurotransmission is only rescued by expressing Csw in both neurons and glia simultaneously. Nevertheless, targeted LoF/GoF mutations in either neurons or glia alone recapitulate the elevated neurotransmission. Thus, PTPN11/Csw mutations in either cell type are sufficient to upregulate presynaptic function, but a dual requirement in neurons and glia is necessary for neurotransmission. Taken together, we conclude that PTPN11/Csw acts in both neurons and glia, with LoF and GoF similarly upregulating MAPK/ERK signaling to enhance presynaptic Synapsin-mediated SV trafficking.
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Affiliation(s)
- Shannon N Leahy
- Departments of Biological Sciences, Vanderbilt University and Medical Center, Nashville, Tennessee 37235
| | - Dominic J Vita
- Departments of Biological Sciences, Vanderbilt University and Medical Center, Nashville, Tennessee 37235
| | - Kendal Broadie
- Departments of Biological Sciences, Vanderbilt University and Medical Center, Nashville, Tennessee 37235
- Cell and Developmental Biology, Vanderbilt University and Medical Center, Nashville, Tennessee 37235
- Pharmacology, Vanderbilt University and Medical Center, Nashville, Tennessee 37235
- Vanderbilt Brain Institute, Vanderbilt University and Medical Center, Nashville, Tennessee 37235
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Longhena F, Faustini G, Brembati V, Pizzi M, Benfenati F, Bellucci A. An updated reappraisal of synapsins: structure, function and role in neurological and psychiatric disorders. Neurosci Biobehav Rev 2021; 130:33-60. [PMID: 34407457 DOI: 10.1016/j.neubiorev.2021.08.011] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2021] [Revised: 07/29/2021] [Accepted: 08/09/2021] [Indexed: 01/02/2023]
Abstract
Synapsins (Syns) are phosphoproteins strongly involved in neuronal development and neurotransmitter release. Three distinct genes SYN1, SYN2 and SYN3, with elevated evolutionary conservation, have been described to encode for Synapsin I, Synapsin II and Synapsin III, respectively. Syns display a series of common features, but also exhibit distinctive localization, expression pattern, post-translational modifications (PTM). These characteristics enable their interaction with other synaptic proteins, membranes and cytoskeletal components, which is essential for the proper execution of their multiple functions in neuronal cells. These include the control of synapse formation and growth, neuron maturation and renewal, as well as synaptic vesicle mobilization, docking, fusion, recycling. Perturbations in the balanced expression of Syns, alterations of their PTM, mutations and polymorphisms of their encoding genes induce severe dysregulations in brain networks functions leading to the onset of psychiatric or neurological disorders. This review presents what we have learned since the discovery of Syn I in 1977, providing the state of the art on Syns structure, function, physiology and involvement in central nervous system disorders.
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Affiliation(s)
- Francesca Longhena
- Division of Pharmacology, Department of Molecular and Translational Medicine, University of Brescia, Viale Europa 11, 25123, Brescia, Italy.
| | - Gaia Faustini
- Division of Pharmacology, Department of Molecular and Translational Medicine, University of Brescia, Viale Europa 11, 25123, Brescia, Italy.
| | - Viviana Brembati
- Division of Pharmacology, Department of Molecular and Translational Medicine, University of Brescia, Viale Europa 11, 25123, Brescia, Italy.
| | - Marina Pizzi
- Division of Pharmacology, Department of Molecular and Translational Medicine, University of Brescia, Viale Europa 11, 25123, Brescia, Italy.
| | - Fabio Benfenati
- Italian Institute of Technology, Via Morego 30, Genova, Italy; IRCSS Policlinico San Martino Hospital, Largo Rosanna Benzi 10, 16132, Genova, Italy.
| | - Arianna Bellucci
- Division of Pharmacology, Department of Molecular and Translational Medicine, University of Brescia, Viale Europa 11, 25123, Brescia, Italy; Laboratory for Preventive and Personalized Medicine, Department of Molecular and Translational Medicine, University of Brescia, Viale Europa 11, 25123, Brescia, Italy.
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Zhang X, Yang Y, Guo L, Zhou J, Niu J, Wang P, Qiang Y, Liu K, Wen Y, Zhang L, Wang F. GPER1 Modulates Synaptic Plasticity During the Development of Temporal Lobe Epilepsy in Rats. Neurochem Res 2021; 46:2019-2032. [PMID: 34076791 DOI: 10.1007/s11064-021-03336-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2021] [Revised: 04/23/2021] [Accepted: 04/27/2021] [Indexed: 11/30/2022]
Abstract
G-protein coupled estrogen receptor 1 (GPER1) is a novel type of estrogen receptor. Several studies have shown that it has an anti-inflammatory action,which plays an important role in remyelination and cognitive ability adjustment. However, whether it is involved in the development of temporal lobe epilepsy (TLE) is still unknown. The present study established a TLE model by intraperitoneal injection of lithium chloride (3 mmol/kg) and pilocarpine (50 mg/kg) in rats to study the effect of GPER1 in the synaptic plasticity during the development of temporal lobe epilepsy. A microinjection cannula was implanted into the lateral ventricle region of rats via a stereotaxic instrument. G-1 is the specific GPER1 agonist and G15 is the specific GPER1 antagonist. The G1 or G15 and Dimethyl sulfoxide were injected into the rat brains in the intervention groups and control group, respectively. After G1 intervention, the learning and memory abilities and hippocampal neuron damage in epileptic rats were significantly improved, while G15 weakened the neuroprotective effect of GPER1. Meanwhile, G1 controlled the abnormal formation of hippocampal mossy fiber sprouting caused by seizures, and participated in the regulation of synaptic plasticity by reducing the expression of Synapsin I and increasing the expression of gephyrin. Inhibitory synapse gephyrin may play a significant role in synaptic plasticity.
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Affiliation(s)
- Xian Zhang
- Ningxia Key Laboratory of Cerebrocranial Diseases, Incubation Base of the National Key Laboratory, Ningxia Medical University, 1160 Shengli Street, Yinchuan, 750001, Ningxia, China
| | - Yang Yang
- Ningxia Key Laboratory of Cerebrocranial Diseases, Incubation Base of the National Key Laboratory, Ningxia Medical University, 1160 Shengli Street, Yinchuan, 750001, Ningxia, China
- School of Basic Medical Sciences, Ningxia Medical University, 1160 Shengli Street, Yinchuan, 750001, Ningxia, China
| | - Li Guo
- School of Basic Medical Sciences, Ningxia Medical University, 1160 Shengli Street, Yinchuan, 750001, Ningxia, China
| | - Jinyu Zhou
- School of Public Health and Management, Ningxia Medical University, 1160 Shengli Street, Yinchuan, 750001, Ningxia, China
| | - Jianguo Niu
- Ningxia Key Laboratory of Cerebrocranial Diseases, Incubation Base of the National Key Laboratory, Ningxia Medical University, 1160 Shengli Street, Yinchuan, 750001, Ningxia, China
- School of Basic Medical Sciences, Ningxia Medical University, 1160 Shengli Street, Yinchuan, 750001, Ningxia, China
| | - Peng Wang
- Ningxia Key Laboratory of Cerebrocranial Diseases, Incubation Base of the National Key Laboratory, Ningxia Medical University, 1160 Shengli Street, Yinchuan, 750001, Ningxia, China
| | - Yuanyuan Qiang
- Ningxia Key Laboratory of Cerebrocranial Diseases, Incubation Base of the National Key Laboratory, Ningxia Medical University, 1160 Shengli Street, Yinchuan, 750001, Ningxia, China
| | - Kunmei Liu
- Ningxia Key Laboratory of Cerebrocranial Diseases, Incubation Base of the National Key Laboratory, Ningxia Medical University, 1160 Shengli Street, Yinchuan, 750001, Ningxia, China
| | - Yujun Wen
- Ningxia Key Laboratory of Cerebrocranial Diseases, Incubation Base of the National Key Laboratory, Ningxia Medical University, 1160 Shengli Street, Yinchuan, 750001, Ningxia, China
- School of Basic Medical Sciences, Ningxia Medical University, 1160 Shengli Street, Yinchuan, 750001, Ningxia, China
| | - Lianxiang Zhang
- Ningxia Key Laboratory of Cerebrocranial Diseases, Incubation Base of the National Key Laboratory, Ningxia Medical University, 1160 Shengli Street, Yinchuan, 750001, Ningxia, China.
- School of Basic Medical Sciences, Ningxia Medical University, 1160 Shengli Street, Yinchuan, 750001, Ningxia, China.
| | - Feng Wang
- Ningxia Key Laboratory of Cerebrocranial Diseases, Incubation Base of the National Key Laboratory, Ningxia Medical University, 1160 Shengli Street, Yinchuan, 750001, Ningxia, China.
- Department of Neurosurgery, General Hospital of Ningxia Medical University, 804 Shengli Street, Yinchuan, 750001, Ningxia, China.
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8
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Function of Drosophila Synaptotagmins in membrane trafficking at synapses. Cell Mol Life Sci 2021; 78:4335-4364. [PMID: 33619613 PMCID: PMC8164606 DOI: 10.1007/s00018-021-03788-9] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2020] [Revised: 01/29/2021] [Accepted: 02/09/2021] [Indexed: 12/13/2022]
Abstract
The Synaptotagmin (SYT) family of proteins play key roles in regulating membrane trafficking at neuronal synapses. Using both Ca2+-dependent and Ca2+-independent interactions, several SYT isoforms participate in synchronous and asynchronous fusion of synaptic vesicles (SVs) while preventing spontaneous release that occurs in the absence of stimulation. Changes in the function or abundance of the SYT1 and SYT7 isoforms alter the number and route by which SVs fuse at nerve terminals. Several SYT family members also regulate trafficking of other subcellular organelles at synapses, including dense core vesicles (DCV), exosomes, and postsynaptic vesicles. Although SYTs are linked to trafficking of multiple classes of synaptic membrane compartments, how and when they interact with lipids, the SNARE machinery and other release effectors are still being elucidated. Given mutations in the SYT family cause disorders in both the central and peripheral nervous system in humans, ongoing efforts are defining how these proteins regulate vesicle trafficking within distinct neuronal compartments. Here, we review the Drosophila SYT family and examine their role in synaptic communication. Studies in this invertebrate model have revealed key similarities and several differences with the predicted activity of their mammalian counterparts. In addition, we highlight the remaining areas of uncertainty in the field and describe outstanding questions on how the SYT family regulates membrane trafficking at nerve terminals.
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9
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Pang J, Hou J, Zhou Z, Ren M, Mo Y, Yang G, Qu Z, Hu Y. Safflower Yellow Improves Synaptic Plasticity in APP/PS1 Mice by Regulating Microglia Activation Phenotypes and BDNF/TrkB/ERK Signaling Pathway. Neuromolecular Med 2020; 22:341-358. [DOI: 10.1007/s12017-020-08591-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2019] [Accepted: 02/02/2020] [Indexed: 02/08/2023]
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10
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Wesseling JF, Phan S, Bushong EA, Siksou L, Marty S, Pérez-Otaño I, Ellisman M. Sparse force-bearing bridges between neighboring synaptic vesicles. Brain Struct Funct 2019; 224:3263-3276. [PMID: 31667576 PMCID: PMC6875159 DOI: 10.1007/s00429-019-01966-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2019] [Accepted: 10/05/2019] [Indexed: 12/28/2022]
Abstract
Most vesicles in the interior of synaptic terminals are clustered in clouds close to active zone regions of the plasma membrane where exocytosis occurs. Electron-dense structures, termed bridges, have been reported between a small minority of pairs of neighboring vesicles within the clouds. Synapsin proteins have been implicated previously, but the existence of the bridges as stable structures in vivo has been questioned. Here we use electron tomography to show that the bridges are present but less frequent in synapsin knockouts compared to wildtype. An analysis of distances between neighbors in wildtype tomograms indicated that the bridges are strong enough to resist centrifugal forces likely induced by fixation with aldehydes. The results confirm that the bridges are stable structures and that synapsin proteins are involved in formation or stabilization.
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Affiliation(s)
- John F Wesseling
- Instituto de Neurociencias, CSIC-UMH, San Juan de Alicante, Spain. .,Departmento de Neurociencias (CIMA), Universidad de Navarra, Pamplona, Spain.
| | - Sébastien Phan
- National Center for Microscopy and Imaging Research, University of California, San Diego, CA, USA
| | - Eric A Bushong
- National Center for Microscopy and Imaging Research, University of California, San Diego, CA, USA
| | - Léa Siksou
- Institut de Biologie de l'ENS (IBENS), École Normale Supérieure, INSERM, CNRS, PSL Research University, Paris, France.,Global Research and Development, Teva Pharmaceutical Industries Ltd, Netanya, Israel
| | - Serge Marty
- Institut de Biologie de l'ENS (IBENS), École Normale Supérieure, INSERM, CNRS, PSL Research University, Paris, France.,Institut du Cerveau et de la Moelle épinière, INSERM U1127, CNRS UMR7225, Université Pierre et Marie Curie, Sorbonne Universités, Paris, France
| | | | - Mark Ellisman
- National Center for Microscopy and Imaging Research and Department of Neuroscience, University of California, San Diego, CA, USA
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11
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Vaden JH, Banumurthy G, Gusarevich ES, Overstreet-Wadiche L, Wadiche JI. The readily-releasable pool dynamically regulates multivesicular release. eLife 2019; 8:47434. [PMID: 31364987 PMCID: PMC6716946 DOI: 10.7554/elife.47434] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2019] [Accepted: 07/30/2019] [Indexed: 01/04/2023] Open
Abstract
The number of neurotransmitter-filled vesicles released into the synaptic cleft with each action potential dictates the reliability of synaptic transmission. Variability of this fundamental property provides diversity of synaptic function across brain regions, but the source of this variability is unclear. The prevailing view is that release of a single (univesicular release, UVR) or multiple vesicles (multivesicular release, MVR) reflects variability in vesicle release probability, a notion that is well-supported by the calcium-dependence of release mode. However, using mouse brain slices, we now demonstrate that the number of vesicles released is regulated by the size of the readily-releasable pool, upstream of vesicle release probability. Our results point to a model wherein protein kinase A and its vesicle-associated target, synapsin, dynamically control release site occupancy to dictate the number of vesicles released without altering release probability. Together these findings define molecular mechanisms that control MVR and functional diversity of synaptic signaling. Our nervous system allows us to rapidly sense and respond to the world around us via cells called neurons that relay electrical signals around the brain and body. When an electrical impulse travelling along one neuron reaches a junction – called a synapse – with a neighboring neuron, it stimulates small containers known as vesicles from the first cell to release their contents into the synapse. These contents then travel across to the neighboring cell and may generate a new electrical impulse. The number of vesicles at a synapse that are ready to be released varies from one to ten. The more vesicles the neuron releases, the more likely the second cell will produce an electrical signal of its own. However, not all electrical signals reaching a synapse stimulate vesicles to be released and some signals only release a single vesicle. What determines how many vesicles are released by a single electrical signal? Some vesicles have a higher likelihood of being released than others, but this “eagerness” does not always predict how many vesicles an individual synapse will actually discharge. Now, Vaden et al. have used brain tissue from mice to test an alternative possibility: the simple idea that the number of vesicles available at the synapse affects how many vesicles are released without altering their eagerness for release. Vaden et al. found that activating an enzyme called protein kinase A increased the number of vesicles released from synapses without changing how likely individual vesicles were to be released. Inhibiting protein kinase A also did not change individual vesicle’s eagerness to be released, but did decrease the number of vesicles that were discharged. Further experiments found that protein kinase A modifies a molecule on the surface of vesicles, known as synapsin, which controls the number of vesicles that are available for release. These findings show that the number of vesicles released at a synapse is controlled by two independently regulated parameters: the number of vesicles that are available, as well as how eager individual vesicles are to be released. The ability of neurons to communicate with each other is disrupted in autism spectrum disorders, Alzheimer’s disease and many other diseases. Learning how neurons communicate in healthy brains will help us understand what happens in the neurons of individuals with these conditions.
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Affiliation(s)
- Jada H Vaden
- Department of Neurobiology, University of Alabama at Birmingham, Birmingham, United States
| | | | - Eugeny S Gusarevich
- Department of Fundamental and Applied Physics, Northern (Arctic) Federal University named after M.V. Lomonosov, Arkhangelsk, Russian Federation
| | | | - Jacques I Wadiche
- Department of Neurobiology, University of Alabama at Birmingham, Birmingham, United States
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12
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Tripchlorolide May Improve Spatial Cognition Dysfunction and Synaptic Plasticity after Chronic Cerebral Hypoperfusion. Neural Plast 2019; 2019:2158285. [PMID: 30923551 PMCID: PMC6409048 DOI: 10.1155/2019/2158285] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2018] [Revised: 11/10/2018] [Accepted: 12/16/2018] [Indexed: 12/11/2022] Open
Abstract
Chronic cerebral hypoperfusion (CCH) is a common pathophysiological mechanism that underlies cognitive decline and degenerative processes in dementia and other neurodegenerative diseases. Low cerebral blood flow (CBF) during CCH leads to disturbances in the homeostasis of hemodynamics and energy metabolism, which in turn results in oxidative stress, astroglia overactivation, and synaptic protein downregulation. These events contribute to synaptic plasticity and cognitive dysfunction after CCH. Tripchlorolide (TRC) is an herbal compound with potent neuroprotective effects. The potential of TRC to improve CCH-induced cognitive impairment has not yet been determined. In the current study, we employed behavioral techniques, electrophysiology, Western blotting, immunofluorescence, and Golgi staining to investigate the effect of TRC on spatial learning and memory impairment and on synaptic plasticity changes in rats after CCH. Our findings showed that TRC could rescue CCH-induced spatial learning and memory dysfunction and improve long-term potentiation (LTP) disorders. We also found that TRC could prevent CCH-induced reductions in N-methyl-D-aspartic acid receptor 2B, synapsin I, and postsynaptic density protein 95 levels. Moreover, TRC upregulated cAMP-response element binding protein, which is an important transcription factor for synaptic proteins. TRC also prevented the reduction in dendritic spine density that is caused by CCH. However, sham rats treated with TRC did not show any improvement in cognition. Because CCH causes disturbances in brain energy homeostasis, TRC therapy may resolve this instability by correcting a variety of cognitive-related signaling pathways. However, for the normal brain, TRC treatment led to neither disturbance nor improvement in neural plasticity. Additionally, this treatment neither impaired nor further improved cognition. In conclusion, we found that TRC can improve spatial learning and memory, enhance synaptic plasticity, upregulate the expression of some synaptic proteins, and increase the density of dendritic spines. Our findings suggest that TRC may be beneficial in the treatment of cognitive impairment induced by CCH.
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13
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Shang J, Wu L, Yang Y, Li Y, Liu Z, Huang Y. Overexpression of Schizosaccharomyces pombe tRNA 3′-end processing enzyme Trz2 leads to an increased cellular iron level and apoptotic cell death. Fungal Genet Biol 2019; 122:11-20. [DOI: 10.1016/j.fgb.2018.10.003] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2017] [Revised: 10/10/2018] [Accepted: 10/23/2018] [Indexed: 01/18/2023]
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14
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Ritzau-Jost A, Jablonski L, Viotti J, Lipstein N, Eilers J, Hallermann S. Apparent calcium dependence of vesicle recruitment. J Physiol 2018; 596:4693-4707. [PMID: 29928766 DOI: 10.1113/jp275911] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2018] [Accepted: 06/11/2018] [Indexed: 11/08/2022] Open
Abstract
KEY POINTS Synaptic transmission relies on the recruitment of neurotransmitter-filled vesicles to presynaptic release sites. Increased intracellular calcium buffering slows the recovery from synaptic depression, suggesting that vesicle recruitment is a calcium-dependent process. However, the molecular mechanisms of vesicle recruitment have only been investigated at some synapses. We investigate the role of calcium in vesicle recruitment at the cerebellar mossy fibre to granule cell synapse. We find that increased intracellular calcium buffering slows the recovery from depression following physiological stimulation. However, the recovery is largely resistant to perturbation of the molecular pathways previously shown to mediate calcium-dependent vesicle recruitment. Furthermore, we find two pools of vesicles with different recruitment speeds and show that models incorporating two pools of vesicles with different calcium-independent recruitment rates can explain our data. In this framework, increased calcium buffering prevents the release of intrinsically fast-recruited vesicles but does not change the vesicle recruitment rates themselves. ABSTRACT During sustained synaptic transmission, recruitment of new transmitter-filled vesicles to the release site counteracts vesicle depletion and thus synaptic depression. An elevated intracellular Ca2+ concentration has been proposed to accelerate the rate of vesicle recruitment at many synapses. This conclusion is often based on the finding that increased intracellular Ca2+ buffering slows the recovery from synaptic depression. However, the molecular mechanisms of the activity-dependent acceleration of vesicle recruitment have only been analysed at some synapses. Using physiological stimulation patterns in postsynaptic recordings and step depolarizations in presynaptic bouton recordings, we investigate vesicle recruitment at cerebellar mossy fibre boutons. We show that increased intracellular Ca2+ buffering slows recovery from depression dramatically. However, pharmacological and genetic interference with calmodulin or the calmodulin-Munc13 pathway, which has been proposed to mediate Ca2+ -dependence of vesicle recruitment, barely affects vesicle recovery from depression. Furthermore, we show that cerebellar mossy fibre boutons have two pools of vesicles: rapidly fusing vesicles that recover slowly and slowly fusing vesicles that recover rapidly. Finally, models adopting such two pools of vesicles with Ca2+ -independent recruitment rates can explain the slowed recovery from depression upon increased Ca2+ buffering. Our data do not rule out the involvement of the calmodulin-Munc13 pathway during stronger stimuli or other molecular pathways mediating Ca2+ -dependent vesicle recruitment at cerebellar mossy fibre boutons. However, we show that well-established two-pool models predict an apparent Ca2+ -dependence of vesicle recruitment. Thus, previous conclusions of Ca2+ -dependent vesicle recruitment based solely on increased intracellular Ca2+ buffering should be considered with caution.
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Affiliation(s)
- Andreas Ritzau-Jost
- Carl-Ludwig-Institute for Physiology, Faculty of Medicine, Leipzig University, Leipzig, Germany
| | - Lukasz Jablonski
- Carl-Ludwig-Institute for Physiology, Faculty of Medicine, Leipzig University, Leipzig, Germany
| | - Julio Viotti
- Carl-Ludwig-Institute for Physiology, Faculty of Medicine, Leipzig University, Leipzig, Germany.,Department of Anatomy and Embryology, Center of Anatomy, University Medical Center Göttingen, Göttingen, Germany
| | - Noa Lipstein
- Max Planck Institute of Experimental Medicine, Göttingen, Germany
| | - Jens Eilers
- Carl-Ludwig-Institute for Physiology, Faculty of Medicine, Leipzig University, Leipzig, Germany
| | - Stefan Hallermann
- Carl-Ludwig-Institute for Physiology, Faculty of Medicine, Leipzig University, Leipzig, Germany
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15
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Herrera JL, Ordoñez-Gutierrez L, Fabrias G, Casas J, Morales A, Hernandez G, Acosta NG, Rodriguez C, Prieto-Valiente L, Garcia-Segura LM, Alonso R, Wandosell FG. Ovarian Function Modulates the Effects of Long-Chain Polyunsaturated Fatty Acids on the Mouse Cerebral Cortex. Front Cell Neurosci 2018; 12:103. [PMID: 29740285 PMCID: PMC5928148 DOI: 10.3389/fncel.2018.00103] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2017] [Accepted: 03/29/2018] [Indexed: 12/31/2022] Open
Abstract
Different dietary ratios of n−6/n−3 long-chain polyunsaturated fatty acids (LC-PUFAs) may alter brain lipid profile, neural activity, and brain cognitive function. To determine whether ovarian hormones influence the effect of diet on the brain, ovariectomized and sham-operated mice continuously treated with placebo or estradiol were fed for 3 months with diets containing low or high n−6/n−3 LC-PUFA ratios. The fatty acid (FA) profile and expression of key neuronal proteins were analyzed in the cerebral cortex, with intact female mice on standard diet serving as internal controls of brain lipidome composition. Diets containing different concentrations of LC-PUFAs greatly modified total FAs, sphingolipids, and gangliosides in the cerebral cortex. Some of these changes were dependent on ovarian hormones, as they were not detected in ovariectomized animals, and in the case of complex lipids, the effect of ovariectomy was partially or totally reversed by continuous administration of estradiol. However, even though differential dietary LC-PUFA content modified the expression of neuronal proteins such as synapsin and its phosphorylation level, PSD-95, amyloid precursor protein (APP), or glial proteins such as glial fibrillary acidic protein (GFAP), an effect also dependent on the presence of the ovary, chronic estradiol treatment was unable to revert the dietary effects on brain cortex synaptic proteins. These results suggest that, in addition to stable estradiol levels, other ovarian hormones such as progesterone and/or cyclic ovarian secretory activity could play a physiological role in the modulation of dietary LC-PUFAs on the cerebral cortex, which may have clinical implications for post-menopausal women on diets enriched with different proportions of n−3 and n−6 LC-PUFAs.
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Affiliation(s)
- Jose L Herrera
- Departamento de Ciencias Médicas Básica and Instituto de Tecnologías Biomédicas, Centro de Investigaciones Biomédicas de Canarias, Universidad de La Laguna, La Laguna, Spain
| | - Lara Ordoñez-Gutierrez
- Centro de Biología Molecular "Severo Ochoa" (CSIC-UAM), Universidad Autónoma de Madrid, Madrid, Spain.,Centro de Investigación Biomédica en Red de Enfermedades Neurodegenerativas, Madrid, Spain
| | - Gemma Fabrias
- Instituto de Química Avanzada de Cataluña (IQAC-CSIC), Barcelona, Spain
| | - Josefina Casas
- Instituto de Química Avanzada de Cataluña (IQAC-CSIC), Barcelona, Spain
| | - Araceli Morales
- Departamento de Ciencias Médicas Básica and Instituto de Tecnologías Biomédicas, Centro de Investigaciones Biomédicas de Canarias, Universidad de La Laguna, La Laguna, Spain
| | - Guadalberto Hernandez
- Departamento de Ciencias Médicas Básica and Instituto de Tecnologías Biomédicas, Centro de Investigaciones Biomédicas de Canarias, Universidad de La Laguna, La Laguna, Spain
| | - Nieves G Acosta
- Departamento de Biología Animal, Edafología y Geología, and Instituto de Tecnologías Biomédicas, Centro de Investigaciones Biomédicas de Canarias, Universidad de La Laguna, Tenerife, Spain
| | - Covadonga Rodriguez
- Departamento de Ciencias Médicas Básica and Instituto de Tecnologías Biomédicas, Centro de Investigaciones Biomédicas de Canarias, Universidad de La Laguna, La Laguna, Spain.,Departamento de Biología Animal, Edafología y Geología, and Instituto de Tecnologías Biomédicas, Centro de Investigaciones Biomédicas de Canarias, Universidad de La Laguna, Tenerife, Spain
| | | | - Luis M Garcia-Segura
- Instituto Cajal (CSIC) and Centro de Investigación Biomédica en Red de Fragilidad y Envejecimiento Saludable, Madrid, Spain
| | - Rafael Alonso
- Departamento de Ciencias Médicas Básica and Instituto de Tecnologías Biomédicas, Centro de Investigaciones Biomédicas de Canarias, Universidad de La Laguna, La Laguna, Spain
| | - Francisco G Wandosell
- Centro de Biología Molecular "Severo Ochoa" (CSIC-UAM), Universidad Autónoma de Madrid, Madrid, Spain.,Centro de Investigación Biomédica en Red de Enfermedades Neurodegenerativas, Madrid, Spain
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16
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Sir2/Sirt1 Links Acute Inebriation to Presynaptic Changes and the Development of Alcohol Tolerance, Preference, and Reward. J Neurosci 2017; 36:5241-51. [PMID: 27170122 DOI: 10.1523/jneurosci.0499-16.2016] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2016] [Accepted: 03/23/2016] [Indexed: 01/01/2023] Open
Abstract
UNLABELLED Acute ethanol inebriation causes neuroadaptive changes in behavior that favor increased intake. Ethanol-induced alterations in gene expression, through epigenetic and other means, are likely to change cellular and neural circuit function. Ethanol markedly changes histone acetylation, and the sirtuin Sir2/SIRT1 that deacetylates histones and transcription factors is essential for the rewarding effects of long-term drug use. The molecular transformations leading from short-term to long-term ethanol responses mostly remain to be discovered. We find that Sir2 in the mushroom bodies of the fruit fly Drosophila promotes short-term ethanol-induced behavioral plasticity by allowing changes in the expression of presynaptic molecules. Acute inebriation strongly reduces Sir2 levels and increases histone H3 acetylation in the brain. Flies lacking Sir2 globally, in the adult nervous system, or specifically in the mushroom body α/β-lobes show reduced ethanol sensitivity and tolerance. Sir2-dependent ethanol reward is also localized to the mushroom bodies, and Sir2 mutants prefer ethanol even without a priming ethanol pre-exposure. Transcriptomic analysis reveals that specific presynaptic molecules, including the synaptic vesicle pool regulator Synapsin, depend on Sir2 to be regulated by ethanol. Synapsin is required for ethanol sensitivity and tolerance. We propose that the regulation of Sir2/SIRT1 by acute inebriation forms part of a transcriptional program in mushroom body neurons to alter presynaptic properties and neural responses to favor the development of ethanol tolerance, preference, and reward. SIGNIFICANCE STATEMENT We identify a mechanism by which acute ethanol inebriation leads to changes in nervous system function that may be an important basis for increasing ethanol intake and addiction liability. The findings are significant because they identify ethanol-driven transcriptional events that target presynaptic properties and direct behavioral plasticity. They also demonstrate that multiple forms of ethanol behavioral plasticity that are relevant to alcoholism are initiated by a shared mechanism. Finally, they link these events to the Drosophila brain region that associates context with innate approach and avoidance responses to code for reward and other higher-order behavior, similar in aspects to the role of the vertebrate mesolimbic system.
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17
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Born G, Grayton HM, Langhorst H, Dudanova I, Rohlmann A, Woodward BW, Collier DA, Fernandes C, Missler M. Genetic targeting of NRXN2 in mice unveils role in excitatory cortical synapse function and social behaviors. Front Synaptic Neurosci 2015; 7:3. [PMID: 25745399 PMCID: PMC4333794 DOI: 10.3389/fnsyn.2015.00003] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2014] [Accepted: 02/03/2015] [Indexed: 01/23/2023] Open
Abstract
Human genetics has identified rare copy number variations and deleterious mutations for all neurexin genes (NRXN1-3) in patients with neurodevelopmental diseases, and electrophysiological recordings in animal brains have shown that Nrxns are important for synaptic transmission. While several mouse models for Nrxn1α inactivation have previously been studied for behavioral changes, very little information is available for other variants. Here, we validate that mice lacking Nrxn2α exhibit behavioral abnormalities, characterized by social interaction deficits and increased anxiety-like behavior, which partially overlap, partially differ from Nrxn1α mutant behaviors. Using patch-clamp recordings in Nrxn2α knockout brains, we observe reduced spontaneous transmitter release at excitatory synapses in the neocortex. We also analyse at this cellular level a novel NRXN2 mouse model that carries a combined deletion of Nrxn2α and Nrxn2β. Electrophysiological analysis of this Nrxn2-mutant mouse shows surprisingly similar defects of excitatory release to Nrxn2α, indicating that the β-variant of Nrxn2 has no strong function in basic transmission at these synapses. Inhibitory transmission as well as synapse densities and ultrastructure remain unchanged in the neocortex of both models. Furthermore, at Nrxn2α and Nrxn2-mutant excitatory synapses we find an altered facilitation and N-methyl-D-aspartate receptor (NMDAR) function because NMDAR-dependent decay time and NMDAR-mediated responses are reduced. As Nrxn can indirectly be linked to NMDAR via neuroligin and PSD-95, the trans-synaptic nature of this complex may help to explain occurrence of presynaptic and postsynaptic effects. Since excitatory/inhibitory imbalances and impairment of NMDAR function are alledged to have a role in autism and schizophrenia, our results support the idea of a related pathomechanism in these disorders.
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Affiliation(s)
- Gesche Born
- Institute of Anatomy and Molecular Neurobiology, Westfälische Wilhelms-University Münster, Germany
| | - Hannah M Grayton
- Social, Genetic and Developmental Psychiatry Centre, Institute of Psychiatry, Psychology and Neuroscience, King's College London London, UK ; Discovery Neuroscience Research, Eli Lilly and Company Ltd. Surrey, UK
| | - Hanna Langhorst
- Institute of Anatomy and Molecular Neurobiology, Westfälische Wilhelms-University Münster, Germany
| | - Irina Dudanova
- Institute of Anatomy and Molecular Neurobiology, Westfälische Wilhelms-University Münster, Germany
| | - Astrid Rohlmann
- Institute of Anatomy and Molecular Neurobiology, Westfälische Wilhelms-University Münster, Germany
| | - Benjamin W Woodward
- Social, Genetic and Developmental Psychiatry Centre, Institute of Psychiatry, Psychology and Neuroscience, King's College London London, UK
| | - David A Collier
- Social, Genetic and Developmental Psychiatry Centre, Institute of Psychiatry, Psychology and Neuroscience, King's College London London, UK ; Discovery Neuroscience Research, Eli Lilly and Company Ltd. Surrey, UK
| | - Cathy Fernandes
- Social, Genetic and Developmental Psychiatry Centre, Institute of Psychiatry, Psychology and Neuroscience, King's College London London, UK
| | - Markus Missler
- Institute of Anatomy and Molecular Neurobiology, Westfälische Wilhelms-University Münster, Germany ; Cluster of Excellence EXC 1003, Cells in Motion Münster, Germany
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18
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García-Pérez E, Mahfooz K, Covita J, Zandueta A, Wesseling JF. Levetiracetam accelerates the onset of supply rate depression in synaptic vesicle trafficking. Epilepsia 2015; 56:535-45. [PMID: 25684406 DOI: 10.1111/epi.12930] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/31/2014] [Indexed: 11/28/2022]
Abstract
OBJECTIVE To determine if levetiracetam (LEV) enhances the impact in excitatory presynaptic terminals of a rate-limiting mechanism in vesicle trafficking termed supply rate depression that emerges to limit synaptic transmission during heavy, epileptiform use. METHODS The effect of LEV was measured with electrophysiologic assays of monosynaptic connections in ex vivo hippocampal slices from wild-type and synapsin knockout mice, and in primary cell culture neurons from wild-type and synaptic vesicle glycoprotein 2a (SV2a) knockout mice. RESULTS LEV enhanced the impact of supply rate depression at Schaffer collateral synapses by shortening the time course for induction. The LEV effect was selective for supply rate depression because other presynaptic vesicle trafficking mechanisms were not affected. The half maximal effective concentration (EC50 ) was ~50 μm. The maximal effect was ~15% and occurred at 100 μm, which is a clinically relevant concentration. An experimental protocol is established for distinguishing atypical antiepileptic drugs (AEDs) that affect supply rate depression, such as LEV, from typical AEDs, such as carbamazepine, that affect upstream mechanisms. The LEV effect was abolished at synapses from knockout mice lacking SV2a and from synapses lacking synapsin 1 and 2. SIGNIFICANCE The findings are consistent with the new hypothesis that LEV acts to treat epilepsy by accelerating the induction of supply rate depression at excitatory synapses during incipient epileptic activity. The absence of the effect in the knockouts confirms that presynaptic function is the target. More specifically, the absence in SV2a knockouts is consistent with previous binding studies suggesting that SV2a is the target for LEV. The absence in synapsin knockouts indicates that the phenotypic target intersects with the biochemical pathway that is altered in synapsin knockouts. The results from synapsin knockouts additionally suggest that development of functional analogs with increased potency might be possible because induction of supply rate depression is faster in synapsin knockouts compared to wild-type synapses treated with LEV.
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19
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Abstract
Synaptic vesicles release their vesicular contents to the extracellular space by Ca(2+)-triggered exocytosis. The Ca(2+)-triggered exocytotic process is regulated by synaptotagmin (Syt), a vesicular Ca(2+)-binding C2 domain protein. Synaptotagmin 1 (Syt1), the most studied major isoform among 16 Syt isoforms, mediates Ca(2+)-triggered synaptic vesicle exocytosis by interacting with the target membranes and SNARE/complexin complex. In synapses of the central nervous system, synaptobrevin 2, a major vesicular SNARE protein, forms a ternary SNARE complex with the plasma membrane SNARE proteins, syntaxin 1 and SNAP25. The affinities of Ca(2+)-dependent interactions between Syt1 and its targets (i.e., SNARE complexes and membranes) are well correlated with the efficacies of the corresponding exocytotic processes. Therefore, different SNARE protein isoforms and membrane lipids, which interact with Syt1 with various affinities, are capable of regulating the efficacy of Syt1-mediated exocytosis. Otoferlin, another type of vesicular C2 domain protein that binds to the membrane in a Ca(2+)-dependent manner, is also involved in the Ca(2+)-triggered synaptic vesicle exocytosis in auditory hair cells. However, the functions of otoferlin in the exocytotic process are not well understood. In addition, at least five different types of synaptic vesicle proteins such as synaptic vesicle protein 2, cysteine string protein α, rab3, synapsin, and a group of proteins containing four transmembrane regions, which includes synaptophysin, synaptogyrin, and secretory carrier membrane protein, are involved in modulating the exocytotic process by regulating the formation and trafficking of synaptic vesicles.
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Affiliation(s)
- Ok-Ho Shin
- Department of Neuroscience and Cell Biology, University of Texas Medical Branch, Galveston, Texas
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20
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Van Hook MJ, Parmelee CM, Chen M, Cork KM, Curto C, Thoreson WB. Calmodulin enhances ribbon replenishment and shapes filtering of synaptic transmission by cone photoreceptors. ACTA ACUST UNITED AC 2014; 144:357-78. [PMID: 25311636 PMCID: PMC4210432 DOI: 10.1085/jgp.201411229] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
At the first synapse in the vertebrate visual pathway, light-evoked changes in photoreceptor membrane potential alter the rate of glutamate release onto second-order retinal neurons. This process depends on the synaptic ribbon, a specialized structure found at various sensory synapses, to provide a supply of primed vesicles for release. Calcium (Ca(2+)) accelerates the replenishment of vesicles at cone ribbon synapses, but the mechanisms underlying this acceleration and its functional implications for vision are unknown. We studied vesicle replenishment using paired whole-cell recordings of cones and postsynaptic neurons in tiger salamander retinas and found that it involves two kinetic mechanisms, the faster of which was diminished by calmodulin (CaM) inhibitors. We developed an analytical model that can be applied to both conventional and ribbon synapses and showed that vesicle resupply is limited by a simple time constant, τ = 1/(Dρδs), where D is the vesicle diffusion coefficient, δ is the vesicle diameter, ρ is the vesicle density, and s is the probability of vesicle attachment. The combination of electrophysiological measurements, modeling, and total internal reflection fluorescence microscopy of single synaptic vesicles suggested that CaM speeds replenishment by enhancing vesicle attachment to the ribbon. Using electroretinogram and whole-cell recordings of light responses, we found that enhanced replenishment improves the ability of cone synapses to signal darkness after brief flashes of light and enhances the amplitude of responses to higher-frequency stimuli. By accelerating the resupply of vesicles to the ribbon, CaM extends the temporal range of synaptic transmission, allowing cones to transmit higher-frequency visual information to downstream neurons. Thus, the ability of the visual system to encode time-varying stimuli is shaped by the dynamics of vesicle replenishment at photoreceptor synaptic ribbons.
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Affiliation(s)
- Matthew J Van Hook
- Department of Ophthalmology and Visual Sciences and Department of Pharmacology and Experimental Neuroscience, University of Nebraska Medical Center, Omaha, NE 68198
| | - Caitlyn M Parmelee
- Department of Mathematics, University of Nebraska-Lincoln, Lincoln, NE 68588
| | - Minghui Chen
- Department of Ophthalmology and Visual Sciences and Department of Pharmacology and Experimental Neuroscience, University of Nebraska Medical Center, Omaha, NE 68198 Department of Ophthalmology and Visual Sciences and Department of Pharmacology and Experimental Neuroscience, University of Nebraska Medical Center, Omaha, NE 68198
| | - Karlene M Cork
- Department of Ophthalmology and Visual Sciences and Department of Pharmacology and Experimental Neuroscience, University of Nebraska Medical Center, Omaha, NE 68198 Department of Ophthalmology and Visual Sciences and Department of Pharmacology and Experimental Neuroscience, University of Nebraska Medical Center, Omaha, NE 68198
| | - Carina Curto
- Department of Mathematics, University of Nebraska-Lincoln, Lincoln, NE 68588 Department of Mathematics, The Pennsylvania State University, University Park, State College, PA 16802
| | - Wallace B Thoreson
- Department of Ophthalmology and Visual Sciences and Department of Pharmacology and Experimental Neuroscience, University of Nebraska Medical Center, Omaha, NE 68198 Department of Ophthalmology and Visual Sciences and Department of Pharmacology and Experimental Neuroscience, University of Nebraska Medical Center, Omaha, NE 68198
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Krzeptowski W, Górska-Andrzejak J, Kijak E, Görlich A, Guzik E, Moore G, Pyza EM. External and circadian inputs modulate synaptic protein expression in the visual system of Drosophila melanogaster. Front Physiol 2014; 5:102. [PMID: 24772085 PMCID: PMC3982107 DOI: 10.3389/fphys.2014.00102] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2014] [Accepted: 02/28/2014] [Indexed: 12/30/2022] Open
Abstract
In the visual system of Drosophila melanogaster the retina photoreceptors form tetrad synapses with the first order interneurons, amacrine cells and glial cells in the first optic neuropil (lamina), in order to transmit photic and visual information to the brain. Using the specific antibodies against synaptic proteins; Bruchpilot (BRP), Synapsin (SYN), and Disc Large (DLG), the synapses in the distal lamina were specifically labeled. Then their abundance was measured as immunofluorescence intensity in flies held in light/dark (LD 12:12), constant darkness (DD), and after locomotor and light stimulation. Moreover, the levels of proteins (SYN and DLG), and mRNAs of the brp, syn, and dlg genes, were measured in the fly's head and brain, respectively. In the head we did not detect SYN and DLG oscillations. We found, however, that in the lamina, DLG oscillates in LD 12:12 and DD but SYN cycles only in DD. The abundance of all synaptic proteins was also changed in the lamina after locomotor and light stimulation. One hour locomotor stimulations at different time points in LD 12:12 affected the pattern of the daily rhythm of synaptic proteins. In turn, light stimulations in DD increased the level of all proteins studied. In the case of SYN, however, this effect was observed only after a short light pulse (15 min). In contrast to proteins studied in the lamina, the mRNA of brp, syn, and dlg genes in the brain was not cycling in LD 12:12 and DD, except the mRNA of dlg in LD 12:12. Our earlier results and obtained in the present study showed that the abundance of BRP, SYN and DLG in the distal lamina, at the tetrad synapses, is regulated by light and a circadian clock while locomotor stimulation affects their daily pattern of expression. The observed changes in the level of synaptic markers reflect the circadian plasticity of tetrad synapses regulated by the circadian clock and external inputs, both specific and unspecific for the visual system.
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Affiliation(s)
- Wojciech Krzeptowski
- Department of Cell Biology and Imaging, Institute of Zoology, Jagiellonian University Kraków, Poland
| | - Jolanta Górska-Andrzejak
- Department of Cell Biology and Imaging, Institute of Zoology, Jagiellonian University Kraków, Poland
| | - Ewelina Kijak
- Department of Cell Biology and Imaging, Institute of Zoology, Jagiellonian University Kraków, Poland
| | - Alicja Görlich
- Department of Cell Biology and Imaging, Institute of Zoology, Jagiellonian University Kraków, Poland
| | - Elżbieta Guzik
- Department of Cell Biology and Imaging, Institute of Zoology, Jagiellonian University Kraków, Poland
| | - Gareth Moore
- Department of Cell Biology and Imaging, Institute of Zoology, Jagiellonian University Kraków, Poland
| | - Elżbieta M Pyza
- Department of Cell Biology and Imaging, Institute of Zoology, Jagiellonian University Kraków, Poland
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22
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Treccani G, Musazzi L, Perego C, Milanese M, Nava N, Bonifacino T, Lamanna J, Malgaroli A, Drago F, Racagni G, Nyengaard JR, Wegener G, Bonanno G, Popoli M. Stress and corticosterone increase the readily releasable pool of glutamate vesicles in synaptic terminals of prefrontal and frontal cortex. Mol Psychiatry 2014; 19:433-43. [PMID: 24535456 DOI: 10.1038/mp.2014.5] [Citation(s) in RCA: 91] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/19/2013] [Revised: 12/18/2013] [Accepted: 01/06/2014] [Indexed: 02/06/2023]
Abstract
Stress and glucocorticoids alter glutamatergic transmission, and the outcome of stress may range from plasticity enhancing effects to noxious, maladaptive changes. We have previously demonstrated that acute stress rapidly increases glutamate release in prefrontal and frontal cortex via glucocorticoid receptor and accumulation of presynaptic SNARE complex. Here we compared the ex vivo effects of acute stress on glutamate release with those of in vitro application of corticosterone, to analyze whether acute effect of stress on glutamatergic transmission is mediated by local synaptic action of corticosterone. We found that acute stress increases both the readily releasable pool (RRP) of vesicles and depolarization-evoked glutamate release, while application in vitro of corticosterone rapidly increases the RRP, an effect dependent on synaptic receptors for the hormone, but does not induce glutamate release for up to 20 min. These findings indicate that corticosterone mediates the enhancement of glutamate release induced by acute stress, and the rapid non-genomic action of the hormone is necessary but not sufficient for this effect.
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Affiliation(s)
- G Treccani
- Laboratory of Neuropsychopharmacology and Functional Neurogenomics-Dipartimento di Scienze Farmacologiche e Biomolecolari and CEND, Università di Milano, Milano, Italy
| | - L Musazzi
- Laboratory of Neuropsychopharmacology and Functional Neurogenomics-Dipartimento di Scienze Farmacologiche e Biomolecolari and CEND, Università di Milano, Milano, Italy
| | - C Perego
- Laboratory of Cell Physiology-Dipartimento di Scienze Farmacologiche e Biomolecolari, Università di Milano, Milano, Italy
| | - M Milanese
- Department of Pharmacy-Unit of Pharmacology and Toxicology, Center of Excellence for Biomedical Research, Università di Genova, Genova, Italy
| | - N Nava
- 1] Stereology and Electron Microscopy Laboratory, Centre for Stochastic Geometry and Advanced Bioimaging, Aarhus University Hospital, Aarhus, Denmark [2] Translational Neuropsychiatry Unit, Department of Clinical Medicine, Aarhus University, Aarhus, Denmark
| | - T Bonifacino
- Department of Pharmacy-Unit of Pharmacology and Toxicology, Center of Excellence for Biomedical Research, Università di Genova, Genova, Italy
| | - J Lamanna
- Neurobiology of Learning Unit, Scientific Institute San Raffaele and Università Vita e Salute San Raffaele, Milano, Italy
| | - A Malgaroli
- Neurobiology of Learning Unit, Scientific Institute San Raffaele and Università Vita e Salute San Raffaele, Milano, Italy
| | - F Drago
- Department of Clinical and Molecular Biomedicine, Section of Pharmacology and Biochemistry, Università di Catania, Catania, Italy
| | - G Racagni
- 1] Laboratory of Neuropsychopharmacology and Functional Neurogenomics-Dipartimento di Scienze Farmacologiche e Biomolecolari and CEND, Università di Milano, Milano, Italy [2] IRCCS San Giovanni di Dio-Fatebenefratelli, Brescia, Italy
| | - J R Nyengaard
- Stereology and Electron Microscopy Laboratory, Centre for Stochastic Geometry and Advanced Bioimaging, Aarhus University Hospital, Aarhus, Denmark
| | - G Wegener
- 1] Translational Neuropsychiatry Unit, Department of Clinical Medicine, Aarhus University, Aarhus, Denmark [2] Centre of Excellence for Pharmaceutical Sciences, North West University, Potchefstroom, South Africa
| | - G Bonanno
- Department of Pharmacy-Unit of Pharmacology and Toxicology, Center of Excellence for Biomedical Research, Università di Genova, Genova, Italy
| | - M Popoli
- Laboratory of Neuropsychopharmacology and Functional Neurogenomics-Dipartimento di Scienze Farmacologiche e Biomolecolari and CEND, Università di Milano, Milano, Italy
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23
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Vasileva M, Renden R, Horstmann H, Gitler D, Kuner T. Overexpression of synapsin Ia in the rat calyx of Held accelerates short-term plasticity and decreases synaptic vesicle volume and active zone area. Front Cell Neurosci 2013; 7:270. [PMID: 24391547 PMCID: PMC3868894 DOI: 10.3389/fncel.2013.00270] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2013] [Accepted: 12/04/2013] [Indexed: 01/10/2023] Open
Abstract
Synapsins are synaptic vesicle (SV) proteins organizing a component of the reserve pool of vesicles at most central nervous system synapses. Alternative splicing of the three mammalian genes results in multiple isoforms that may differentially contribute to the organization and maintenance of the SV pools. To address this, we first characterized the expression pattern of synapsin isoforms in the rat calyx of Held. At postnatal day 16, synapsins Ia, Ib, IIb and IIIa were present, while IIa-known to sustain repetitive transmission in glutamatergic terminals-was not detectable. To test if the synapsin I isoforms could mediate IIa-like effect, and if this depends on the presence of the E-domain, we overexpressed either synapsin Ia or synapsin Ib in the rat calyx of Held via recombinant adeno-associated virus-mediated gene transfer. Although the size and overall structure of the perturbed calyces remained unchanged, short-term depression and recovery from depression were accelerated upon overexpression of synapsin I isoforms. Using electron microscopic three-dimensional reconstructions we found a redistribution of SV clusters proximal to the active zones (AZ) alongside with a decrease of both AZ area and SV volume. The number of SVs at individual AZs was strongly reduced. Hence, our data indicate that the amount of synapsin Ia expressed in the calyx regulates the rate and extent of short-term synaptic plasticity by affecting vesicle recruitment to the AZ. Finally, our study reveals a novel contribution of synapsin Ia to define the surface area of AZs.
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Affiliation(s)
- Mariya Vasileva
- Institute of Anatomy and Cell Biology, Heidelberg University Heidelberg, Germany
| | - Robert Renden
- Institute of Anatomy and Cell Biology, Heidelberg University Heidelberg, Germany
| | - Heinz Horstmann
- Institute of Anatomy and Cell Biology, Heidelberg University Heidelberg, Germany
| | - Daniel Gitler
- Department of Physiology and Cell Biology, Faculty of Health Sciences and Zlotowski Center for Neuroscience, Ben-Gurion University of the Negev Beer-Sheva, Israel
| | - Thomas Kuner
- Institute of Anatomy and Cell Biology, Heidelberg University Heidelberg, Germany
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Dynamic Control of Synaptic Vesicle Replenishment and Short-Term Plasticity by Ca2+-Calmodulin-Munc13-1 Signaling. Neuron 2013; 79:82-96. [DOI: 10.1016/j.neuron.2013.05.011] [Citation(s) in RCA: 120] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/13/2013] [Indexed: 02/02/2023]
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25
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HDAC4 governs a transcriptional program essential for synaptic plasticity and memory. Cell 2013; 151:821-834. [PMID: 23141539 DOI: 10.1016/j.cell.2012.09.037] [Citation(s) in RCA: 195] [Impact Index Per Article: 17.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2011] [Revised: 06/11/2012] [Accepted: 09/18/2012] [Indexed: 11/20/2022]
Abstract
Neuronal activity influences genes involved in circuit development and information processing. However, the molecular basis of this process remains poorly understood. We found that HDAC4, a histone deacetylase that shuttles between the nucleus and cytoplasm, controls a transcriptional program essential for synaptic plasticity and memory. The nuclear import of HDAC4 and its association with chromatin is negatively regulated by NMDA receptors. In the nucleus, HDAC4 represses genes encoding constituents of central synapses, thereby affecting synaptic architecture and strength. Furthermore, we show that a truncated form of HDAC4 encoded by an allele associated with mental retardation is a gain-of-function nuclear repressor that abolishes transcription and synaptic transmission despite the loss of the deacetylase domain. Accordingly, mice carrying a mutant that mimics this allele exhibit deficits in neurotransmission, spatial learning, and memory. These studies elucidate a mechanism of experience-dependent plasticity and define the biological role of HDAC4 in the brain.
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Synapsins contribute to the dynamic spatial organization of synaptic vesicles in an activity-dependent manner. J Neurosci 2012; 32:12214-27. [PMID: 22933803 DOI: 10.1523/jneurosci.1554-12.2012] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
The precise subcellular organization of synaptic vesicles (SVs) at presynaptic sites allows for rapid and spatially restricted exocytotic release of neurotransmitter. The synapsins (Syns) are a family of presynaptic proteins that control the availability of SVs for exocytosis by reversibly tethering them to each other and to the actin cytoskeleton in a phosphorylation-dependent manner. Syn ablation leads to reduction in the density of SV proteins in nerve terminals and increased synaptic fatigue under high-frequency stimulation, accompanied by the development of an epileptic phenotype. We analyzed cultured neurons from wild-type and Syn I,II,III(-/-) triple knock-out (TKO) mice and found that SVs were severely dispersed in the absence of Syns. Vesicle dispersion did not affect the readily releasable pool of SVs, whereas the total number of SVs was considerably reduced at synapses of TKO mice. Interestingly, dispersion apparently involved exocytosis-competent SVs as well; it was not affected by stimulation but was reversed by chronic neuronal activity blockade. Altogether, these findings indicate that Syns are essential to maintain the dynamic structural organization of synapses and the size of the reserve pool of SVs during intense SV recycling, whereas an additional Syn-independent mechanism, whose molecular substrate remains to be clarified, targets SVs to synaptic boutons at rest and might be outpaced by activity.
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27
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Vasileva M, Horstmann H, Geumann C, Gitler D, Kuner T. Synapsin-dependent reserveo pool of synaptic vesicles supports replenishment of the readily releasable pool under intense synaptic transmission. Eur J Neurosci 2012; 36:3005-20. [DOI: 10.1111/j.1460-9568.2012.08225.x] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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28
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Synapsin selectively controls the mobility of resting pool vesicles at hippocampal terminals. J Neurosci 2012; 32:3969-80. [PMID: 22442064 DOI: 10.1523/jneurosci.5058-11.2012] [Citation(s) in RCA: 64] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Presynaptic terminals are specialized sites for information transmission where vesicles fuse with the plasma membrane and are locally recycled. Recent work has extended this classical view, with the observation that a subset of functional vesicles is dynamically shared between adjacent terminals by lateral axonal transport. Conceptually, such transport would be expected to disrupt vesicle retention around the active zone, yet terminals are characterized by a high-density vesicle cluster, suggesting that counteracting stabilizing mechanisms must operate against this tendency. The synapsins are a family of proteins that associate with synaptic vesicles and determine vesicle numbers at the terminal, but their specific function remains controversial. Here, using multiple quantitative fluorescence-based approaches and electron microscopy, we show that synapsin is instrumental for resisting vesicle dispersion and serves as a regulatory element for controlling lateral vesicle sharing between synapses. Deleting synapsin disrupts the organization of presynaptic vesicle clusters, making their boundaries hard to define. Concurrently, the fraction of vesicles amenable to transport is increased, and more vesicles are translocated to the axon. Importantly, in neurons from synapsin knock-out mice the resting and recycling pools are equally mobile. Synapsin, when present, specifically restricts the mobility of resting pool vesicles without affecting the division of vesicles between these pools. Specific expression of synapsin IIa, the sole isoform affecting synaptic depression, rescues the knock-out phenotype. Together, our results show that synapsin is pivotal for maintaining synaptic vesicle cluster integrity and that it contributes to the regulated sharing of vesicles between terminals.
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29
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Synaptic functions of invertebrate varicosities: what molecular mechanisms lie beneath. Neural Plast 2012; 2012:670821. [PMID: 22655209 PMCID: PMC3359714 DOI: 10.1155/2012/670821] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2011] [Accepted: 02/27/2012] [Indexed: 11/26/2022] Open
Abstract
In mammalian brain, the cellular and molecular events occurring in both synapse formation and plasticity are difficult to study due to the large number of factors involved in these processes and because the contribution of each component is not well defined. Invertebrates, such as Drosophila, Aplysia, Helix, Lymnaea, and Helisoma, have proven to be useful models for studying synaptic assembly and elementary forms of learning. Simple nervous system, cellular accessibility, and genetic simplicity are some examples of the invertebrate advantages that allowed to improve our knowledge about evolutionary neuronal conserved mechanisms. In this paper, we present an overview of progresses that elucidates cellular and molecular mechanisms underlying synaptogenesis and synapse plasticity in invertebrate varicosities and their validation in vertebrates. In particular, the role of invertebrate synapsin in the formation of presynaptic terminals and the cell-to-cell interactions that induce specific structural and functional changes in their respective targets will be analyzed.
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30
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Mutso AA, Radzicki D, Baliki MN, Huang L, Banisadr G, Centeno MV, Radulovic J, Martina M, Miller RJ, Apkarian AV. Abnormalities in hippocampal functioning with persistent pain. J Neurosci 2012; 32:5747-56. [PMID: 22539837 PMCID: PMC3365570 DOI: 10.1523/jneurosci.0587-12.2012] [Citation(s) in RCA: 341] [Impact Index Per Article: 28.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2012] [Revised: 03/06/2012] [Accepted: 03/12/2012] [Indexed: 02/07/2023] Open
Abstract
Chronic pain patients exhibit increased anxiety, depression, and deficits in learning and memory. Yet how persistent pain affects the key brain area regulating these behaviors, the hippocampus, has remained minimally explored. In this study we investigated the impact of spared nerve injury (SNI) neuropathic pain in mice on hippocampal-dependent behavior and underlying cellular and molecular changes. In parallel, we measured the hippocampal volume of three groups of chronic pain patients. We found that SNI animals were unable to extinguish contextual fear and showed increased anxiety-like behavior. Additionally, SNI mice compared with Sham animals exhibited hippocampal (1) reduced extracellular signal-regulated kinase expression and phosphorylation, (2) decreased neurogenesis, and (3) altered short-term synaptic plasticity. To relate the observed hippocampal abnormalities with human chronic pain, we measured the volume of human hippocampus in chronic back pain (CBP), complex regional pain syndrome (CRPS), and osteoarthritis patients (OA). Compared with controls, CBP and CRPS, but not OA, had significantly less bilateral hippocampal volume. These results indicate that hippocampus-mediated behavior, synaptic plasticity, and neurogenesis are abnormal in neuropathic rodents. The changes may be related to the reduction in hippocampal volume we see in chronic pain patients, and these abnormalities may underlie learning and emotional deficits commonly observed in such patients.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | - A. Vania Apkarian
- Departments of Physiology
- Anesthesia and Surgery, Feinberg School of Medicine, Northwestern University, Chicago, Illinois 60611
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31
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Farisello P, Boido D, Nieus T, Medrihan L, Cesca F, Valtorta F, Baldelli P, Benfenati F. Synaptic and extrasynaptic origin of the excitation/inhibition imbalance in the hippocampus of synapsin I/II/III knockout mice. Cereb Cortex 2012; 23:581-93. [PMID: 22368083 DOI: 10.1093/cercor/bhs041] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Synapsins (Syn I, Syn II, and Syn III) are a family of synaptic vesicle phosphoproteins regulating synaptic transmission and plasticity. SYN1/2 genes have been identified as major epilepsy susceptibility genes in humans and synapsin I/II/III triple knockout (TKO) mice are epileptic. However, excitatory and inhibitory synaptic transmission and short-term plasticity have never been analyzed in intact neuronal circuits of TKO mice. To clarify the generation and expression of the epileptic phenotype, we performed patch-clamp recordings in the CA1 region of acute hippocampal slices from 1-month-old presymptomatic and 6-month-old epileptic TKO mice and age-matched controls. We found a strong imbalance between basal glutamatergic and γ-aminobutyric acid (GABA)ergic transmission with increased evoked excitatory postsynaptic current and impaired evoked inhibitory postsynaptic current amplitude. This imbalance was accompanied by a parallel derangement of short-term plasticity paradigms, with enhanced facilitation of glutamatergic transmission in the presymptomatic phase and milder depression of inhibitory synapses in the symptomatic phase. Interestingly, a lower tonic GABA(A) current due to the impaired GABA release is responsible for the more depolarized resting potential found in TKO CA1 neurons, which makes them more susceptible to fire. All these changes preceded the appearance of epilepsy, indicating that the distinct changes in excitatory and inhibitory transmission due to the absence of Syns initiate the epileptogenic process.
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Affiliation(s)
- Pasqualina Farisello
- Department of Neuroscience and Brain Technologies, The Italian Institute of Technology, 16163 Genova, Italy.
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32
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Orenbuch A, Ayelet O, Shulman Y, Yoav S, Lipstein N, Noa L, Bechar A, Amit B, Lavy Y, Yotam L, Brumer E, Eliaz B, Vasileva M, Mariya V, Kahn J, Joy K, Barki-Harrington L, Liza BH, Kuner T, Thomas K, Gitler D, Daniel G. Inhibition of exocytosis or endocytosis blocks activity-dependent redistribution of synapsin. J Neurochem 2011; 120:248-58. [PMID: 22066784 DOI: 10.1111/j.1471-4159.2011.07579.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
The synaptic vesicle cycle encompasses the pre-synaptic events that drive neurotransmission. Influx of calcium leads to the fusion of synaptic vesicles with the plasma membrane and the release of neurotransmitter, closely followed by endocytosis. Vacated release sites are repopulated with vesicles which are then primed for release. When activity is intense, reserve vesicles may be mobilized to counteract an eventual decline in transmission. Recently, interplay between endocytosis and repopulation of the readily releasable pool of vesicles has been identified. In this study, we show that exo-endocytosis is necessary to enable detachment of synapsin from reserve pool vesicles during synaptic activity. We report that blockage of exocytosis in cultured mouse hippocampal neurons, either by tetanus toxin or by the deletion of munc13, inhibits the activity-dependent redistribution of synapsin from the pre-synaptic terminal into the axon. Likewise, perturbation of endocytosis with dynasore or by a dynamin dominant-negative mutant fully prevents synapsin redistribution. Such inhibition of synapsin redistribution occurred despite the efficient phosphorylation of synapsin at its protein kinase A/CaMKI site, indicating that disengagement of synapsin from the vesicles requires exocytosis and endocytosis in addition to phosphorylation. Our results therefore reveal hitherto unidentified feedback within the synaptic vesicle cycle involving the synapsin-managed reserve pool.
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Affiliation(s)
- Ayelet Orenbuch
- Department of Physiology and Neurobiology, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer-Sheva, Israel
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Inhibition of presynaptic Na(+)/K(+)-ATPase reduces readily releasable pool size at the avian end-bulb of Held synapse. Neurosci Res 2011; 72:117-28. [PMID: 22100365 DOI: 10.1016/j.neures.2011.11.003] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2011] [Revised: 10/09/2011] [Accepted: 11/04/2011] [Indexed: 11/23/2022]
Abstract
A glutamatergic end-bulb synapse in the avian nucleus magnocellularis relays temporal sound information from the auditory nerve. Here, we show that presynaptic Na(+)/K(+)-ATPase (NKA) activity at this synapse contributes to the maintenance of the readily releasable pool (RRP) of vesicles, thereby preserving synaptic strength. Whole-cell voltage clamp recordings were made from chick brainstem slices to examine the effects of NKA blocker dihydroouabain (DHO) on synaptic transmission. DHO suppressed the amplitude of EPSCs in a dose-dependent manner. This suppression was caused by a decrease in the number of neurotransmitter quanta released because DHO increased the coefficient of variation of EPSC amplitude and reduced the frequency but not the amplitude of miniature EPSCs. Cumulative plots of EPSC amplitude during a stimulus train revealed that DHO reduced the RRP size without affecting vesicular release probability. DHO did not affect [Ca(2+)](i)-dependent processes, such as the paired-pulse ratio or recovery time course from the paired-pulse depression, suggesting a minimal effect on Ca(2+) concentration in the presynaptic terminal. Using mathematical models of synaptic depression, we further demonstrated the contribution of RRP size to the synaptic strength during a high-frequency stimulus train to highlight the importance of presynaptic NKA in the auditory synapse.
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34
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Nakashima AS, Hussain Butt R, Dyck RH. Alterations in protein and gene expression within the barrel cortices of ZnT3 knockout mice: Experience-independent and dependent changes. Neurochem Int 2011; 59:860-70. [DOI: 10.1016/j.neuint.2011.08.007] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2011] [Revised: 07/27/2011] [Accepted: 08/08/2011] [Indexed: 12/12/2022]
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35
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Abstract
At least two rate-limiting mechanisms in vesicle trafficking operate at mouse Schaffer collateral synapses, but their molecular/physical identities are unknown. The first mechanism determines the baseline rate at which reserve vesicles are supplied to a readily releasable pool. The second causes the supply rate to depress threefold when synaptic transmission is driven hard for extended periods. Previous models invoked depletion of a reserve vesicle pool to explain the reductions in the supply rate, but the mass-action assumption at their core is not compatible with kinetic measurements of neurotransmission under maximal-use conditions. Here we develop a new theoretical model of rate-limiting steps in vesicle trafficking that is compatible with previous and new measurements. A physical interpretation is proposed where local reserve pools consisting of four vesicles are tethered to individual release sites and are replenished stochastically in an all-or-none fashion. We then show that the supply rate depresses more rapidly in synapsin knock-outs and that the phenotype can be fully explained by changing the value of the single parameter in the model that would specify the size of the local reserve pools. Vesicle-trafficking rates between pools were not affected. Finally, optical imaging experiments argue against alternative interpretations of the theoretical model where vesicle trafficking is inhibited without reserve pool depletion. This new conceptual framework will be useful for distinguishing which of the multiple molecular and cell biological mechanisms involved in vesicle trafficking are rate limiting at different levels of synaptic throughput and are thus candidates for physiological and pharmacological modulation.
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36
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Humeau Y, Candiani S, Ghirardi M, Poulain B, Montarolo P. Functional roles of synapsin: Lessons from invertebrates. Semin Cell Dev Biol 2011; 22:425-33. [DOI: 10.1016/j.semcdb.2011.07.018] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2011] [Accepted: 07/13/2011] [Indexed: 12/18/2022]
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37
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Abstract
In Drosophila, aversive associative memory of an odor consists of heterogeneous components with different stabilities. Here we report that Bruchpilot (Brp), a ubiquitous presynaptic active zone protein, is required for olfactory memory. Brp was shown before to facilitate efficient vesicle release, particularly at low stimulation frequencies. Transgenic knockdown in the Kenyon cells of the mushroom body, the second-order olfactory interneurons, revealed that Brp is required for olfactory memory. We further demonstrate that Brp in the Kenyon cells preferentially functions for anesthesia-resistant memory. Another presynaptic protein, Synapsin, was shown previously to be required selectively for the labile anesthesia-sensitive memory, which is less affected in brp knockdown. Thus, consolidated and labile components of aversive olfactory memory can be dissociated by the function of different presynaptic proteins.
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Etholm L, Lindén H, Eken T, Heggelund P. Electroencephalographic characterization of seizure activity in the synapsin I/II double knockout mouse. Brain Res 2011; 1383:270-88. [DOI: 10.1016/j.brainres.2011.01.070] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2010] [Revised: 01/20/2011] [Accepted: 01/20/2011] [Indexed: 10/18/2022]
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Boido D, Farisello P, Cesca F, Ferrea E, Valtorta F, Benfenati F, Baldelli P. Cortico-hippocampal hyperexcitability in synapsin I/II/III knockout mice: age-dependency and response to the antiepileptic drug levetiracetam. Neuroscience 2010; 171:268-83. [PMID: 20804820 DOI: 10.1016/j.neuroscience.2010.08.046] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2010] [Revised: 08/03/2010] [Accepted: 08/20/2010] [Indexed: 10/19/2022]
Abstract
Synapsins (SynI, SynII, SynIII) are a multigene family of synaptic vesicle (SV) phosphoproteins implicated in the regulation of synaptic transmission and plasticity. Synapsin I, II, I/II and I/II/III knockout mice are epileptic and SYN1/2 genes have been identified as major epilepsy susceptibility genes in humans. We analyzed cortico-hippocampal epileptiform activity induced by 4-aminopyridine (4AP) in acute slices from presymptomatic (3-weeks-old) and symptomatic (1-year-old) Syn I/II/III triple knockout (TKO) mice and aged-matched triple wild type (TWT) controls and assessed the effect of the SV-targeted antiepileptic drug (AED) levetiracetam (LEV) in reverting the epileptic phenotype. Both fast and slow interictal (I-IC) and ictal (IC) events were observed in both genotypes. The incidence of fast I-IC events was higher in presymptomatic TKO slices, while frequency and latency of I-IC events were similar in both genotypes. The major age and genotype effects were observed in IC activity, that was much more pronounced in 3-weeks-old TKO and persisted with age, while it disappeared from 1-year-old TWT slices. LEV virtually suppressed fast I-IC and IC discharges from 3-weeks-old TWT slices, while it only increased the latency of fast I-IC and IC activity in TKO slices. Analysis of I-IC events in patch-clamped CA1 pyramidal neurons revealed that LEV increased the inhibitory/excitatory ratio of I-IC activity in both genotypes. The lower LEV potency in TKO slices of both ages was associated with a decreased expression of SV2A, a SV protein acting as LEV receptor, in cortex and hippocampus. The results demonstrate that deletion of Syn genes is associated with a higher propensity to 4AP-induced epileptic paroxysms that precedes the onset of epilepsy and consolidates with age. LEV ameliorates such hyper excitability by enhancing the inhibition/excitation ratio, although the effect is hindered in TKO slices which exhibit a concomitant decrease in the levels of the LEV receptor SV2A.
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Affiliation(s)
- D Boido
- Department of Neuroscience and Brain Technologies, The Italian Institute of Technology, Via Morego 30, 16163 Genova, Italy
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40
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Knapek S, Gerber B, Tanimoto H. Synapsin is selectively required for anesthesia-sensitive memory. Learn Mem 2010; 17:76-9. [PMID: 20154352 DOI: 10.1101/lm.1661810] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Odor-shock memory in Drosophila melanogaster consists of heterogeneous components each with different dynamics. We report that a null mutant for the evolutionarily conserved synaptic protein Synapsin entails a memory deficit selectively in early memory, leaving later memory as well as sensory motor function unaffected. Notably, a consolidated memory component remaining after cold-anesthesia is not impaired, suggesting that only anesthesia-sensitive memory [ASM] depends on Synapsin. The lack of Synapsin does not further impair the memory deficit of mutants for the rutabaga gene encoding the type I adenylyl cyclase. This suggests that cAMP signaling, through a Synapsin-dependent mechanism, may underlie the formation of a labile memory component.
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Crow T, Xue-Bian JJ. Proteomic analysis of post-translational modifications in conditioned Hermissenda. Neuroscience 2009; 165:1182-90. [PMID: 19961907 DOI: 10.1016/j.neuroscience.2009.11.066] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2009] [Revised: 11/20/2009] [Accepted: 11/25/2009] [Indexed: 12/21/2022]
Abstract
Post-translational modifications of proteins are a major determinant of biological function. Phosphorylation of proteins involved in signal transduction contributes to the induction and maintenance of several examples of cellular and synaptic plasticity. In this study we have identified phosphoproteins regulated by Pavlovian conditioning in lysates of Hermissenda nervous systems using two-dimensional electrophoresis (2DE) in conjunction with (32)P labeling, fluorescence based phosphoprotein in-gel staining, and mass spectrometry. Modification of protein phosphorylation regulated by conditioning was first assessed by densitometric analysis of (32)P labeled proteins resolved by 2DE from lysates of conditioned and pseudorandom control nervous systems. An independent assessment of phosphorylation regulated by conditioning was obtained from an examination of 2D gels stained with Pro-Q Diamond phosphoprotein dye. Mass spectrometric analysis of protein digests from phosphoprotein stained analytical gels or Coomassie Blue stained preparative gels provided for the identification of phosphoproteins that exhibited statistically significant increased phosphorylation in conditioned groups as compared to pseudorandom controls. A previously identified cytoskeletal related protein, Csp24 (24 kDa conditioned stimulus pathway phosphoprotein), involved in intermediate-term memory exhibited significantly increased phosphorylation detected 24 h post-conditioning. Our results show that proteins involved in diverse cellular functions such as transcriptional regulation, cell signaling, cytoskeletal regulation, metabolic activity, and protein degradation contribute to long-term post-translational modifications associated with Pavlovian conditioning.
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Affiliation(s)
- T Crow
- Department of Neurobiology and Anatomy, University of Texas Medical School, Houston, TX 77030, USA.
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42
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Abstract
Activity and protein synthesis act cooperatively to generate persistent changes in synaptic responses. This forms the basis for enduring memory in adults. Activity also shapes neural circuits developmentally, but whether protein synthesis plays a congruent function in this process is poorly understood. Here, we show that brief periods of global or local protein synthesis inhibition decrease the synaptic vesicles available for fusion and increase synapse elimination. Ca(2+)/calmodulin-dependent protein kinase II (CaMKII) is a critical target; its levels are controlled by rapid turnover, and blocking its activity or knocking it down recapitulates the effects of protein synthesis inhibition. Mature presynaptic terminals show decreased sensitivity to protein synthesis inhibition, and resistance coincides with a developmental switch in regulation from CaMKII to PKA (protein kinase A). These findings demonstrate a novel mechanism regulating presynaptic activity and synapse elimination during development, and suggest that protein translation acts coordinately with activity to selectively stabilize appropriate synaptic interactions.
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43
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Gelman BB, Nguyen TP. Synaptic proteins linked to HIV-1 infection and immunoproteasome induction: proteomic analysis of human synaptosomes. J Neuroimmune Pharmacol 2009; 5:92-102. [PMID: 19693676 PMCID: PMC2824116 DOI: 10.1007/s11481-009-9168-0] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2009] [Accepted: 08/05/2009] [Indexed: 10/25/2022]
Abstract
Infection of the central nervous system with human immunodeficiency virus type 1 (HIV-1) can produce morphological changes in the neocortical synaptodendritic arbor that are correlated with neurocognitive impairment. To determine whether HIV-1 infection influences the protein composition of human synapses, a proteomic study of isolated nerve endings was undertaken. Synaptosomes from frontal neocortex were isolated using isopyknic centrifugation from 19 human brain specimens. Purity and enrichment were assessed by measuring pre- and postsynaptic protein markers. Two-dimensional polyacrylamide gel electrophoresis and matrix-assisted laser desorption ionization time-of-flight mass spectrometry was used to screen for proteins differentially expressed in HIV/AIDS. The concentrations of 31 candidate protein spots were potentially abnormal in HIV-infected decedents with HIV encephalitis and/or increased expression of immunoproteasome subunits. Immunoblots showed that the concentration of some of them was related to HIV-1 infection of the brain and immunoproteasome (IPS) induction. Synapsin 1b and stathmin were inversely related to brain HIV-1 load; 14-3-3zeta and 14-4-4epsilon proteins were higher in subjects with HIV-1 loads. Perturbed synaptosome proteins were linked with IPS subunit composition, and 14-3-3zeta was histologically colocalized with IPS subunits in stained neocortical neurons. Proteomics illustrates that certain human proteins within the synaptic compartment are involved with changes in the synaptodendritic arbor and neurocognitive impairment in HIV-1-infected people.
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Affiliation(s)
- Benjamin B Gelman
- Department of Pathology, University of Texas Medical Branch, 301 University Blvd, Galveston, TX 77555, USA.
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44
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Mass spectrometrical characterisation of mouse and rat synapsin isoforms 2a and 2b. Amino Acids 2009; 38:1131-43. [DOI: 10.1007/s00726-009-0323-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2009] [Accepted: 06/30/2009] [Indexed: 11/27/2022]
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Conti AC, Maas JW, Moulder KL, Jiang X, Dave BA, Mennerick S, Muglia LJ. Adenylyl cyclases 1 and 8 initiate a presynaptic homeostatic response to ethanol treatment. PLoS One 2009; 4:e5697. [PMID: 19479030 PMCID: PMC2682654 DOI: 10.1371/journal.pone.0005697] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2008] [Accepted: 04/16/2009] [Indexed: 12/31/2022] Open
Abstract
BACKGROUND Although ethanol exerts widespread action in the brain, only recently has progress been made in understanding the specific events occurring at the synapse during ethanol exposure. Mice deficient in the calcium-stimulated adenylyl cyclases, AC1 and AC8 (DKO), demonstrate increased sedation duration and impaired phosphorylation by protein kinase A (PKA) following acute ethanol treatment. While not direct targets for ethanol, we hypothesize that these cyclases initiate a homeostatic presynaptic response by PKA to reactivate neurons from ethanol-mediated inhibition. METHODOLOGY/PRINCIPAL FINDINGS Here, we have used phosphoproteomic techniques and identified several presynaptic proteins that are phosphorylated in the brains of wild type mice (WT) after ethanol exposure, including synapsin, a known PKA target. Phosphorylation of synapsins I and II, as well as phosphorylation of non-PKA targets, such as, eukaryotic elongation factor-2 (eEF-2) and dynamin is significantly impaired in the brains of DKO mice. This deficit is primarily driven by AC1, as AC1-deficient, but not AC8-deficient mice also demonstrate significant reductions in phosphorylation of synapsin and eEF-2 in cortical and hippocampal tissues. DKO mice have a reduced pool of functional recycling vesicles and fewer active terminals as measured by FM1-43 uptake compared to WT controls, which may be a contributing factor to the impaired presynaptic response to ethanol treatment. CONCLUSIONS/SIGNIFICANCE These data demonstrate that calcium-stimulated AC-dependent PKA activation in the presynaptic terminal, primarily driven by AC1, is a critical event in the reactivation of neurons following ethanol-induced activity blockade.
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Affiliation(s)
- Alana C Conti
- Department of Pediatrics, Washington University in St. Louis, St. Louis, Missouri, United States of America.
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Chiappalone M, Casagrande S, Tedesco M, Valtorta F, Baldelli P, Martinoia S, Benfenati F. Opposite Changes in Glutamatergic and GABAergic Transmission Underlie the Diffuse Hyperexcitability of Synapsin I–Deficient Cortical Networks. Cereb Cortex 2008; 19:1422-39. [DOI: 10.1093/cercor/bhn182] [Citation(s) in RCA: 93] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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Corradi A, Zanardi A, Giacomini C, Onofri F, Valtorta F, Zoli M, Benfenati F. Synapsin-I- and synapsin-II-null mice display an increased age-dependent cognitive impairment. J Cell Sci 2008; 121:3042-51. [DOI: 10.1242/jcs.035063] [Citation(s) in RCA: 87] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Synapsin I (SynI) and synapsin II (SynII) are major synaptic vesicle (SV) proteins that function in the regulation of the availability of SVs for release in mature neurons. SynI and SynII show a high level of sequence similarity and share many functions in vivo, although distinct physiological roles for the two proteins have been proposed. Both SynI–/– and SynII–/– mice have a normal lifespan, but exhibit a decreased number of SVs and synaptic depression upon high-frequency stimulation. Because of the role of the synapsin proteins in synaptic organization and plasticity, we studied the long-lasting effects of synapsin deletion on the phenotype of SynI–/– and SynII–/– mice during aging. Both SynI–/– and SynII–/– mice displayed behavioural defects that emerged during aging and involved emotional memory in both mutants, and spatial memory in SynII–/– mice. These abnormalities, which were more pronounced in SynII–/– mice, were associated with neuronal loss and gliosis in the cerebral cortex and hippocampus. The data indicate that SynI and SynII have specific and non-redundant functions, and that synaptic dysfunctions associated with synapsin mutations negatively modulate cognitive performances and neuronal survival during senescence.
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Affiliation(s)
- Anna Corradi
- Department of Experimental Medicine, Section of Physiology, University of Genova and Istituto Nazionale di Neuroscienze, Viale Benedetto XV, 3 16132 Genova, Italy
| | - Alessio Zanardi
- Department of Biomedical Sciences, Section of Physiology, University of Modena, Via Campi 287, 41100 Modena, Italy
| | - Caterina Giacomini
- Department of Experimental Medicine, Section of Physiology, University of Genova and Istituto Nazionale di Neuroscienze, Viale Benedetto XV, 3 16132 Genova, Italy
| | - Franco Onofri
- Department of Experimental Medicine, Section of Physiology, University of Genova and Istituto Nazionale di Neuroscienze, Viale Benedetto XV, 3 16132 Genova, Italy
| | - Flavia Valtorta
- San Raffaele Scientific Institute/Vita-Salute University, IIT Unit of Molecular Neuroscience and Istituto Nazionale di Neuroscienze, via Olgettina 58, 20132 Milano, Italy
| | - Michele Zoli
- Department of Biomedical Sciences, Section of Physiology, University of Modena, Via Campi 287, 41100 Modena, Italy
| | - Fabio Benfenati
- Department of Experimental Medicine, Section of Physiology, University of Genova and Istituto Nazionale di Neuroscienze, Viale Benedetto XV, 3 16132 Genova, Italy
- Department of Neuroscience and Brain Technologies, The Italian Institute of Technology, Via Morego 30, 16163 Genova, Italy
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Regulation of synaptic transmission by presynaptic CaMKII and BK channels. Mol Neurobiol 2008; 38:153-66. [PMID: 18759010 DOI: 10.1007/s12035-008-8039-7] [Citation(s) in RCA: 98] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2008] [Accepted: 08/14/2008] [Indexed: 12/28/2022]
Abstract
Ca(2+)/calmodulin-dependent protein kinase II (CaMKII) and the BK channel are enriched at the presynaptic nerve terminal, where CaMKII associates with synaptic vesicles whereas the BK channel colocalizes with voltage-sensitive Ca(2+) channels in the plasma membrane. Mounting evidence suggests that these two proteins play important roles in controlling neurotransmitter release. Presynaptic BK channels primarily serve as a negative regulator of neurotransmitter release. In contrast, presynaptic CaMKII either enhances or inhibits neurotransmitter release and synaptic plasticity depending on experimental or physiological conditions and properties of specific synapses. The different functions of presynaptic CaMKII appear to be mediated by distinct downstream proteins, including the BK channel.
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49
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Schmidtko A, Luo C, Gao W, Geisslinger G, Kuner R, Tegeder I. Genetic deletion of synapsin II reduces neuropathic pain due to reduced glutamate but increased GABA in the spinal cord dorsal horn. Pain 2008; 139:632-643. [PMID: 18701217 DOI: 10.1016/j.pain.2008.06.018] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2008] [Revised: 05/12/2008] [Accepted: 06/23/2008] [Indexed: 01/21/2023]
Abstract
The synaptic vesicle protein synapsin II is specifically expressed in synaptic terminals of primary afferent nociceptive neurons and regulates transmitter release in the spinal cord dorsal horn. Here, we assessed its role in nerve injury-evoked molecular and behavioral adaptations in models of peripheral neuropathic pain using mice genetically lacking synapsin II. Deficiency of synapsin II resulted in reduced mechanical and cold allodynia in two models of peripheral neuropathic pain. This was associated with decreased glutamate release in the dorsal horn of the spinal cord upon sciatic nerve injury or capsaicin application onto the sciatic nerve and reduced calcium signals in spinal cord slices upon persistent activation of primary afferents. In addition, the expression of the vesicular glutamate transporters, VGLUT1 and VGLUT2, was strongly reduced in synapsin II knockout mice in the spinal cord. Conversely, synapsin II knockout mice showed a stronger and longer-lasting increase of GABA in lamina II of the dorsal horn after nerve injury than wild type mice. These results suggest that synapsin II is involved in the regulation of glutamate and GABA release in the spinal cord after nerve injury, and that a imbalance between glutamatergic and GABAergic synaptic transmission contributes to the manifestation of neuropathic pain.
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Affiliation(s)
- Achim Schmidtko
- pharmazentrum frankfurt/ZAFES, Institut für Klinische Pharmakologie, Klinikum der Johann Wolfgang Goethe Universität, Theodor Stern Kai 7, 60590 Frankfurt am Main, Germany Pharmakologisches Institut, Universität Heidelberg, Germany
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50
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Oberlander JG, Erskine MS. Receipt of vaginal-cervical stimulation modifies synapsin content in limbic areas of the female rat. Neuroscience 2008; 153:581-93. [PMID: 18407423 DOI: 10.1016/j.neuroscience.2008.02.048] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2007] [Revised: 01/30/2008] [Accepted: 02/01/2008] [Indexed: 10/22/2022]
Abstract
Female rats require a sufficient amount and pattern of vaginal-cervical stimulation to initiate neuroendocrine changes required for the successful implantation of a fertilized ovum in the uterus. These changes are characterized by twice daily prolactin surges that last 10-12 days. Following a sterile mating, the endocrine changes are still observed, and are termed pseudopregnancy (PSP). The mating stimulation required to initiate these changes prior to pregnancy or PSP has a neural representation, which we have termed the intromission mnemonic. We sought to examine if the formation of the intromission mnemonic is accompanied by alterations in the number or density of synapses in limbic areas by immuno-labeling a pre-synaptic protein, synapsin. Groups of cycling female rats on proestrus day received either 15 or 5 intromissions or mounts-without intromissions from a vasectomized male; an additional time-matched control group was left in the home cage. All females were perfused after 90 min or 8 h. The brains were removed and sliced, and the amygdala and hippocampus immunostained for synapsin, then imaged by confocal microscopy. We found that 90 min after mating sufficient for PSP, the number of synapsin puncta (points of immunoreactivity equivalent to a synapse) was decreased and the intensity of the synapsin staining was increased in the posterodorsal medial amygdala (MePD). A similar reduction of puncta was observed in the CA1 region of the hippocampus, and an increase of intensity occurred in the basolateral amygdala. Spaced intromissions had no effect on synapsin expression anywhere examined. Intensity reductions unrelated to receipt of vaginal-cervical stimulation were observed in the hippocampus. None of these effects were observed after 8 h. Together, these results raise the possibility that synapses in the MePD may be pruned after mating stimulation, resulting in pathway-specific stabilization that contributes to the intromission mnemonic associated with the establishment of PSP.
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Affiliation(s)
- J G Oberlander
- Department of Biology, Boston University, Boston, MA 02215, USA.
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