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Salazar Lázaro A, Trimbuch T, Vardar G, Rosenmund C. The stability of the primed pool of synaptic vesicles and the clamping of spontaneous neurotransmitter release rely on the integrity of the C-terminal half of the SNARE domain of syntaxin-1A. eLife 2024; 12:RP90775. [PMID: 38512129 PMCID: PMC10957171 DOI: 10.7554/elife.90775] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/22/2024] Open
Abstract
The SNARE proteins are central in membrane fusion and, at the synapse, neurotransmitter release. However, their involvement in the dual regulation of the synchronous release while maintaining a pool of readily releasable vesicles remains unclear. Using a chimeric approach, we performed a systematic analysis of the SNARE domain of STX1A by exchanging the whole SNARE domain or its N- or C-terminus subdomains with those of STX2. We expressed these chimeric constructs in STX1-null hippocampal mouse neurons. Exchanging the C-terminal half of STX1's SNARE domain with that of STX2 resulted in a reduced RRP accompanied by an increased release rate, while inserting the C-terminal half of STX1's SNARE domain into STX2 leads to an enhanced priming and decreased release rate. Additionally, we found that the mechanisms for clamping spontaneous, but not for Ca2+-evoked release, are particularly susceptible to changes in specific residues on the outer surface of the C-terminus of the SNARE domain of STX1A. Particularly, mutations of D231 and R232 affected the fusogenicity of the vesicles. We propose that the C-terminal half of the SNARE domain of STX1A plays a crucial role in the stabilization of the RRP as well as in the clamping of spontaneous synaptic vesicle fusion through the regulation of the energetic landscape for fusion, while it also plays a covert role in the speed and efficacy of Ca2+-evoked release.
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Affiliation(s)
- Andrea Salazar Lázaro
- Department of Neurophysiology, Charité-Universitätsmedizin Berlin, Humboldt-Universität zu Berlin, Berlin Institute of HealthBerlinGermany
| | - Thorsten Trimbuch
- Department of Neurophysiology, Charité-Universitätsmedizin Berlin, Humboldt-Universität zu Berlin, Berlin Institute of HealthBerlinGermany
| | - Gülçin Vardar
- Department of Neurophysiology, Charité-Universitätsmedizin Berlin, Humboldt-Universität zu Berlin, Berlin Institute of HealthBerlinGermany
| | - Christian Rosenmund
- Department of Neurophysiology, Charité-Universitätsmedizin Berlin, Humboldt-Universität zu Berlin, Berlin Institute of HealthBerlinGermany
- NeuroCure Excellence ClusterBerlinGermany
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2
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Martínez-Mármol R, Muhaisen A, Cotrufo T, Roselló-Busquets C, Ros O, Hernaiz-Llorens M, Pérez-Branguli F, Andrés RM, Parcerisas A, Pascual M, Ulloa F, Soriano E. Syntaxin-1 is necessary for UNC5A-C/Netrin-1-dependent macropinocytosis and chemorepulsion. Front Mol Neurosci 2023; 16:1253954. [PMID: 37829513 PMCID: PMC10565356 DOI: 10.3389/fnmol.2023.1253954] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2023] [Accepted: 09/04/2023] [Indexed: 10/14/2023] Open
Abstract
Introduction Brain connectivity requires correct axonal guidance to drive axons to their appropriate targets. This process is orchestrated by guidance cues that exert attraction or repulsion to developing axons. However, the intricacies of the cellular machinery responsible for the correct response of growth cones are just being unveiled. Netrin-1 is a bifunctional molecule involved in axon pathfinding and cell migration that induces repulsion during postnatal cerebellar development. This process is mediated by UNC5 homolog receptors located on external granule layer (EGL) tracts. Methods Biochemical, imaging and cell biology techniques, as well as syntaxin-1A/B (Stx1A/B) knock-out mice were used in primary cultures and brain explants. Results and discussion Here, we demonstrate that this response is characterized by enhanced membrane internalization through macropinocytosis, but not clathrin-mediated endocytosis. We show that UNC5A, UNC5B, and UNC5C receptors form a protein complex with the t-SNARE syntaxin-1. By combining botulinum neurotoxins, an shRNA knock-down strategy and Stx1 knock-out mice, we demonstrate that this SNARE protein is required for Netrin1-induced macropinocytosis and chemorepulsion, suggesting that Stx1 is crucial in regulating Netrin-1-mediated axonal guidance.
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Affiliation(s)
- Ramón Martínez-Mármol
- Department of Cell Biology, Physiology and Immunology, Faculty of Biology and Institute of Neurosciences, Universitat de Barcelona (UB), Barcelona, Spain
- Clem Jones Centre for Ageing Dementia Research, Queensland Brain Institute, The University of Queensland, Brisbane, QLD, Australia
| | - Ashraf Muhaisen
- Department of Cell Biology, Physiology and Immunology, Faculty of Biology and Institute of Neurosciences, Universitat de Barcelona (UB), Barcelona, Spain
- Centro de Investigación Biomédica en Red Sobre Enfermedades Neurodegenerativas (CIBERNED-CIBER), ISCIII, Madrid, Spain
| | - Tiziana Cotrufo
- Department of Cell Biology, Physiology and Immunology, Faculty of Biology and Institute of Neurosciences, Universitat de Barcelona (UB), Barcelona, Spain
- Centro de Investigación Biomédica en Red Sobre Enfermedades Neurodegenerativas (CIBERNED-CIBER), ISCIII, Madrid, Spain
| | - Cristina Roselló-Busquets
- Department of Cell Biology, Physiology and Immunology, Faculty of Biology and Institute of Neurosciences, Universitat de Barcelona (UB), Barcelona, Spain
| | - Oriol Ros
- Department of Cell Biology, Physiology and Immunology, Faculty of Biology and Institute of Neurosciences, Universitat de Barcelona (UB), Barcelona, Spain
| | - Marc Hernaiz-Llorens
- Department of Cell Biology, Physiology and Immunology, Faculty of Biology and Institute of Neurosciences, Universitat de Barcelona (UB), Barcelona, Spain
| | - Francesc Pérez-Branguli
- Department of Cell Biology, Physiology and Immunology, Faculty of Biology and Institute of Neurosciences, Universitat de Barcelona (UB), Barcelona, Spain
- IZKF Junior Research Group and BMBF Research Group Neuroscience, IZKF, Friedrich-Alexander-Universitaet Erlangen-Nuernberg, Erlangen, Germany
| | - Rosa Maria Andrés
- Department of Cell Biology, Physiology and Immunology, Faculty of Biology and Institute of Neurosciences, Universitat de Barcelona (UB), Barcelona, Spain
- Centro de Investigación Biomédica en Red Sobre Enfermedades Neurodegenerativas (CIBERNED-CIBER), ISCIII, Madrid, Spain
| | - Antoni Parcerisas
- Tissue Repair and Regeneration Laboratory (TR2Lab), Institut de Recerca i Innovació en Ciències de la Vida i de la Salut a la Catalunya Central (IRIS-CC), Vic, Spain
- Biosciences Department, Faculty of Sciences, Technology and Engineerings, University of Vic - Central University of Catalonia (UVic-UCC), Vic, Spain
| | - Marta Pascual
- Department of Cell Biology, Physiology and Immunology, Faculty of Biology and Institute of Neurosciences, Universitat de Barcelona (UB), Barcelona, Spain
- Centro de Investigación Biomédica en Red Sobre Enfermedades Neurodegenerativas (CIBERNED-CIBER), ISCIII, Madrid, Spain
| | - Fausto Ulloa
- Department of Cell Biology, Physiology and Immunology, Faculty of Biology and Institute of Neurosciences, Universitat de Barcelona (UB), Barcelona, Spain
- Centro de Investigación Biomédica en Red Sobre Enfermedades Neurodegenerativas (CIBERNED-CIBER), ISCIII, Madrid, Spain
| | - Eduardo Soriano
- Department of Cell Biology, Physiology and Immunology, Faculty of Biology and Institute of Neurosciences, Universitat de Barcelona (UB), Barcelona, Spain
- Centro de Investigación Biomédica en Red Sobre Enfermedades Neurodegenerativas (CIBERNED-CIBER), ISCIII, Madrid, Spain
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3
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Yang X, Tu W, Gao X, Zhang Q, Guan J, Zhang J. Functional regulation of syntaxin-1: An underlying mechanism mediating exocytosis in neuroendocrine cells. Front Endocrinol (Lausanne) 2023; 14:1096365. [PMID: 36742381 PMCID: PMC9892835 DOI: 10.3389/fendo.2023.1096365] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/12/2022] [Accepted: 01/05/2023] [Indexed: 01/20/2023] Open
Abstract
The fusion of the secretory vesicle with the plasma membrane requires the assembly of soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) protein complexes formed by synaptobrevin, syntaxin-1, and SNAP-25. Within the pathway leading to exocytosis, the transitions between the "open" and "closed" conformations of syntaxin-1 function as a switch for the fusion of vesicles with the plasma membranes; rapid assembly and disassembly of syntaxin-1 clusters on the plasma membrane provide docking and fusion sites for secretory vesicles in neuroendocrine cells; and the fully zippered trans-SNARE complex, which requires the orderly, rapid and accurate binding of syntaxin-1 to other SNARE proteins, play key roles in triggering fusion. All of these reactions that affect exocytosis under physiological conditions are tightly regulated by multiple factors. Here, we review the current evidence for the involvement of syntaxin-1 in the mechanism of neuroendocrine cell exocytosis, discuss the roles of multiple factors such as proteins, lipids, protein kinases, drugs, and toxins in SNARE complex-mediated membrane fusion, and present an overview of syntaxin-1 mutation-associated diseases with a view to developing novel mechanistic therapeutic targets for the treatment of neuroendocrine disorders.
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Affiliation(s)
- Xinquan Yang
- Anesthesia and Perioperative Medicine laboratory, the Affiliated Lianyungang Hospital of Jiangsu University, Lianyungang, China
| | - Weifeng Tu
- Faculty of Anesthesioloy, Suzhou Hospital Affiliated to Medical School of Nanjing University, Suzhou, China
| | - Xuzhu Gao
- Department of Central Laboratory, Lianyungang Hospital Affiliated to Jiangsu University, Lianyungang, China
| | - Qi Zhang
- Anesthesia and Perioperative Medicine laboratory, the Affiliated Lianyungang Hospital of Jiangsu University, Lianyungang, China
| | - Jinping Guan
- Anesthesia and Perioperative Medicine laboratory, the Affiliated Lianyungang Hospital of Jiangsu University, Lianyungang, China
| | - Junlong Zhang
- Anesthesia and Perioperative Medicine laboratory, the Affiliated Lianyungang Hospital of Jiangsu University, Lianyungang, China
- *Correspondence: Junlong Zhang,
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Michetti C, Falace A, Benfenati F, Fassio A. Synaptic genes and neurodevelopmental disorders: From molecular mechanisms to developmental strategies of behavioral testing. Neurobiol Dis 2022; 173:105856. [PMID: 36070836 DOI: 10.1016/j.nbd.2022.105856] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2021] [Revised: 08/29/2022] [Accepted: 08/30/2022] [Indexed: 10/14/2022] Open
Abstract
Synaptopathies are a class of neurodevelopmental disorders caused by modification in genes coding for synaptic proteins. These proteins oversee the process of neurotransmission, mainly controlling the fusion and recycling of synaptic vesicles at the presynaptic terminal, the expression and localization of receptors at the postsynapse and the coupling between the pre- and the postsynaptic compartments. Murine models, with homozygous or heterozygous deletion for several synaptic genes or knock-in for specific pathogenic mutations, have been developed. They have proved to be extremely informative for understanding synaptic physiology, as well as for clarifying the patho-mechanisms leading to developmental delay, epilepsy and motor, cognitive and social impairments that are the most common clinical manifestations of neurodevelopmental disorders. However, the onset of these disorders emerges during infancy and adolescence while the behavioral phenotyping is often conducted in adult mice, missing important information about the impact of synaptic development and maturation on the manifestation of the behavioral phenotype. Here, we review the main achievements obtained by behavioral testing in murine models of synaptopathies and propose a battery of behavioral tests to improve classification, diagnosis and efficacy of potential therapeutic treatments. Our aim is to underlie the importance of studying behavioral development and better focusing on disease onset and phenotypes.
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Affiliation(s)
- Caterina Michetti
- Department of Experimental Medicine, University of Genoa, Genoa, Italy; Center for Synaptic Neuroscience, Istituto Italiano di Tecnologia, Genoa, Italy.
| | - Antonio Falace
- Pediatric Neurology, Neurogenetics and Neurobiology Unit and Laboratories, Children's Hospital A. Meyer-University of Florence, Florence, Italy
| | - Fabio Benfenati
- Center for Synaptic Neuroscience, Istituto Italiano di Tecnologia, Genoa, Italy; IRCCS Ospedale Policlinico San Martino, Genoa, Italy
| | - Anna Fassio
- Department of Experimental Medicine, University of Genoa, Genoa, Italy; IRCCS Ospedale Policlinico San Martino, Genoa, Italy.
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5
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Özdemir Ç, Şahin N, Edgünlü T. Vesicle trafficking with snares: a perspective for autism. Mol Biol Rep 2022; 49:12193-12202. [PMID: 36198849 DOI: 10.1007/s11033-022-07970-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2022] [Accepted: 09/21/2022] [Indexed: 11/30/2022]
Abstract
Vesicle-mediated membrane traffic is the mechanism fundamental to many biological events, especially the release of neurotransmitters. The main proteins of the mechanism that mediates membrane fusion in vesicle-mediated membrane traffic are N-ethylmaleimide sensitive factor (NSF) supplemental protein (SNAP) receptor (SNAREs) proteins. SNAREs are classified into vesicle-associated SNAREs (vesicle-SNAREs/v-SNAREs) and target membrane-associated SNAREs (target-SNARE/t-SNAREs). Autism spectrum disorders (ASD) are neurodevelopmental disorders characterized by many symptoms, especially complications in social communication and stereotypical behaviours. Defects in synaptogenesis and neurotransmission, oxidative stress, and developmental defects in the early stages of development are defined in the pathogenesis of the disease. SNARE proteins are on the basis of synaptogenesis and neurotransmission. Although the formation mechanisms and underlying causes of the SNARE complex are not fully understood, expression differences, polymorphisms, abnormal expressions or dysfunctions of the proteins that make up the SNARE complex have been associated with many neurodevelopmental diseases, including autism. Further understanding of SNARE mechanisms is crucial both for understanding ASD and for developing new treatments. In this review, the formation mechanisms of the SNARE complex and the roles of various factors involved in this process are explained. In addition, a brief evaluation of clinical and basic studies on the SNARE complex in autism spectrum disorders was made.
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Affiliation(s)
- Çilem Özdemir
- Department of Medical Biology, Health Sciences Institution, Muğla Sıtkı Koçman University, Mugla, Turkey
| | - Nilfer Şahin
- Department of Child and Adolescent Mental Health Diseases School of Medicine, Muğla Sıtkı Koçman University, Mugla, Turkey
| | - Tuba Edgünlü
- Department of Medical Biology, School of Medicine, Muğla Sıtkı Koçman University, 48000, Mugla, Turkey.
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Vardar G, Salazar-Lázaro A, Zobel S, Trimbuch T, Rosenmund C. Syntaxin-1A modulates vesicle fusion in mammalian neurons via juxtamembrane domain dependent palmitoylation of its transmembrane domain. eLife 2022; 11:78182. [PMID: 35638903 PMCID: PMC9183232 DOI: 10.7554/elife.78182] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2022] [Accepted: 05/30/2022] [Indexed: 11/16/2022] Open
Abstract
SNAREs are undoubtedly one of the core elements of synaptic transmission. Contrary to the well characterized function of their SNARE domains bringing the plasma and vesicular membranes together, the level of contribution of their juxtamembrane domain (JMD) and the transmembrane domain (TMD) to the vesicle fusion is still under debate. To elucidate this issue, we analyzed three groups of STX1A mutations in cultured mouse hippocampal neurons: (1) elongation of STX1A’s JMD by three amino acid insertions in the junction of SNARE-JMD or JMD-TMD; (2) charge reversal mutations in STX1A’s JMD; and (3) palmitoylation deficiency mutations in STX1A’s TMD. We found that both JMD elongations and charge reversal mutations have position-dependent differential effects on Ca2+-evoked and spontaneous neurotransmitter release. Importantly, we show that STX1A’s JMD regulates the palmitoylation of STX1A’s TMD and loss of STX1A palmitoylation either through charge reversal mutation K260E or by loss of TMD cysteines inhibits spontaneous vesicle fusion. Interestingly, the retinal ribbon specific STX3B has a glutamate in the position corresponding to the K260E mutation in STX1A and mutating it with E259K acts as a molecular on-switch. Furthermore, palmitoylation of post-synaptic STX3A can be induced by the exchange of its JMD with STX1A’s JMD together with the incorporation of two cysteines into its TMD. Forced palmitoylation of STX3A dramatically enhances spontaneous vesicle fusion suggesting that STX1A regulates spontaneous release through two distinct mechanisms: one through the C-terminal half of its SNARE domain and the other through the palmitoylation of its TMD.
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Affiliation(s)
- Gülçin Vardar
- Department of Neurophysiology, Charité - Universitätsmedizin Berlin, Berlin, Germany
| | - Andrea Salazar-Lázaro
- Department of Neurophysiology, Charité - Universitätsmedizin Berlin, Berlin, Germany
| | - Sina Zobel
- Department of Neurophysiology, Charité - Universitätsmedizin Berlin, Berlin, Germany
| | - Thorsten Trimbuch
- Department of Neurophysiology, Charité - Universitätsmedizin Berlin, Berlin, Germany
| | - Christian Rosenmund
- Department of Neurophysiology, Charité - Universitätsmedizin Berlin, Berlin, Germany
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7
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Spoto G, Valentini G, Saia MC, Butera A, Amore G, Salpietro V, Nicotera AG, Di Rosa G. Synaptopathies in Developmental and Epileptic Encephalopathies: A Focus on Pre-synaptic Dysfunction. Front Neurol 2022; 13:826211. [PMID: 35350397 PMCID: PMC8957959 DOI: 10.3389/fneur.2022.826211] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2021] [Accepted: 01/24/2022] [Indexed: 12/25/2022] Open
Abstract
The proper connection between the pre- and post-synaptic nervous cells depends on any element constituting the synapse: the pre- and post-synaptic membranes, the synaptic cleft, and the surrounding glial cells and extracellular matrix. An alteration of the mechanisms regulating the physiological synergy among these synaptic components is defined as “synaptopathy.” Mutations in the genes encoding for proteins involved in neuronal transmission are associated with several neuropsychiatric disorders, but only some of them are associated with Developmental and Epileptic Encephalopathies (DEEs). These conditions include a heterogeneous group of epilepsy syndromes associated with cognitive disturbances/intellectual disability, autistic features, and movement disorders. This review aims to elucidate the pathogenesis of these conditions, focusing on mechanisms affecting the neuronal pre-synaptic terminal and its role in the onset of DEEs, including potential therapeutic approaches.
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Affiliation(s)
- Giulia Spoto
- Unit of Child Neurology and Psychiatry, Department of Human Pathology of the Adult and Developmental Age “Gaetano Barresi”, University of Messina, Messina, Italy
| | - Giulia Valentini
- Unit of Child Neurology and Psychiatry, Department of Human Pathology of the Adult and Developmental Age “Gaetano Barresi”, University of Messina, Messina, Italy
| | - Maria Concetta Saia
- Unit of Child Neurology and Psychiatry, Department of Human Pathology of the Adult and Developmental Age “Gaetano Barresi”, University of Messina, Messina, Italy
| | - Ambra Butera
- Unit of Child Neurology and Psychiatry, Department of Human Pathology of the Adult and Developmental Age “Gaetano Barresi”, University of Messina, Messina, Italy
| | - Greta Amore
- Unit of Child Neurology and Psychiatry, Department of Human Pathology of the Adult and Developmental Age “Gaetano Barresi”, University of Messina, Messina, Italy
| | - Vincenzo Salpietro
- Department of Neuromuscular Disorders, Institute of Neurology, University College London, London, United Kingdom
- Pediatric Neurology and Muscular Diseases Unit, Istituto di Ricovero e Cura a Carattere Scientifico (IRCCS) Giannina Gaslini, Genoa, Italy
- Department of Neurosciences, Rehabilitation, Ophthalmology, Genetics, Maternal and Child Health, University of Genoa, Genoa, Italy
- *Correspondence: Vincenzo Salpietro
| | - Antonio Gennaro Nicotera
- Unit of Child Neurology and Psychiatry, Department of Human Pathology of the Adult and Developmental Age “Gaetano Barresi”, University of Messina, Messina, Italy
| | - Gabriella Di Rosa
- Unit of Child Neurology and Psychiatry, Department of Human Pathology of the Adult and Developmental Age “Gaetano Barresi”, University of Messina, Messina, Italy
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8
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Cali E, Rocca C, Salpietro V, Houlden H. Epileptic Phenotypes Associated With SNAREs and Related Synaptic Vesicle Exocytosis Machinery. Front Neurol 2022; 12:806506. [PMID: 35095745 PMCID: PMC8792400 DOI: 10.3389/fneur.2021.806506] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2021] [Accepted: 11/16/2021] [Indexed: 01/29/2023] Open
Abstract
SNAREs (soluble N-ethylmaleimide sensitive factor attachment protein receptor) are an heterogeneous family of proteins that, together with their key regulators, are implicated in synaptic vesicle exocytosis and synaptic transmission. SNAREs represent the core component of this protein complex. Although the specific mechanisms of the SNARE machinery is still not completely uncovered, studies in recent years have provided a clearer understanding of the interactions regulating the essential fusion machinery for neurotransmitter release. Mutations in genes encoding SNARE proteins or SNARE complex associated proteins have been associated with a variable spectrum of neurological conditions that have been recently defined as “SNAREopathies.” These include neurodevelopmental disorder, autism spectrum disorder (ASD), movement disorders, seizures and epileptiform abnormalities. The SNARE phenotypic spectrum associated with seizures ranges from simple febrile seizures and infantile spasms, to severe early-onset epileptic encephalopathies. Our study aims to review and delineate the epileptic phenotypes associated with dysregulation of synaptic vesicle exocytosis and transmission, focusing on the main proteins of the SNARE core complex (STX1B, VAMP2, SNAP25), tethering complex (STXBP1), and related downstream regulators.
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Affiliation(s)
- Elisa Cali
- MRC Centre for Neuromuscular Diseases, UCL Queen Square Institute of Neurology, London, United Kingdom
| | - Clarissa Rocca
- MRC Centre for Neuromuscular Diseases, UCL Queen Square Institute of Neurology, London, United Kingdom
| | - Vincenzo Salpietro
- MRC Centre for Neuromuscular Diseases, UCL Queen Square Institute of Neurology, London, United Kingdom
| | - Henry Houlden
- MRC Centre for Neuromuscular Diseases, UCL Queen Square Institute of Neurology, London, United Kingdom
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9
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Sauvola CW, Littleton JT. SNARE Regulatory Proteins in Synaptic Vesicle Fusion and Recycling. Front Mol Neurosci 2021; 14:733138. [PMID: 34421538 PMCID: PMC8377282 DOI: 10.3389/fnmol.2021.733138] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2021] [Accepted: 07/20/2021] [Indexed: 01/01/2023] Open
Abstract
Membrane fusion is a universal feature of eukaryotic protein trafficking and is mediated by the soluble N-ethylmaleimide sensitive factor attachment protein receptor (SNARE) family. SNARE proteins embedded in opposing membranes spontaneously assemble to drive membrane fusion and cargo exchange in vitro. Evolution has generated a diverse complement of SNARE regulatory proteins (SRPs) that ensure membrane fusion occurs at the right time and place in vivo. While a core set of SNAREs and SRPs are common to all eukaryotic cells, a specialized set of SRPs within neurons confer additional regulation to synaptic vesicle (SV) fusion. Neuronal communication is characterized by precise spatial and temporal control of SNARE dynamics within presynaptic subdomains specialized for neurotransmitter release. Action potential-elicited Ca2+ influx at these release sites triggers zippering of SNAREs embedded in the SV and plasma membrane to drive bilayer fusion and release of neurotransmitters that activate downstream targets. Here we discuss current models for how SRPs regulate SNARE dynamics and presynaptic output, emphasizing invertebrate genetic findings that advanced our understanding of SRP regulation of SV cycling.
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Affiliation(s)
- Chad W Sauvola
- The Picower Institute for Learning and Memory, Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA, United States
| | - J Troy Littleton
- The Picower Institute for Learning and Memory, Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA, United States.,Department of Biology, Massachusetts Institute of Technology, Cambridge, MA, United States
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10
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Kunii M, Noguchi Y, Yoshimura SI, Kanda S, Iwano T, Avriyanti E, Atik N, Sato T, Sato K, Ogawa M, Harada A. SNAP23 deficiency causes severe brain dysplasia through the loss of radial glial cell polarity. J Cell Biol 2021; 220:e201910080. [PMID: 33332551 PMCID: PMC7754684 DOI: 10.1083/jcb.201910080] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2019] [Revised: 08/23/2020] [Accepted: 10/23/2020] [Indexed: 02/06/2023] Open
Abstract
In the developing brain, the polarity of neural progenitor cells, termed radial glial cells (RGCs), is important for neurogenesis. Intercellular adhesions, termed apical junctional complexes (AJCs), at the apical surface between RGCs are necessary for cell polarization. However, the mechanism by which AJCs are established remains unclear. Here, we show that a SNARE complex composed of SNAP23, VAMP8, and Syntaxin1B has crucial roles in AJC formation and RGC polarization. Central nervous system (CNS)-specific ablation of SNAP23 (NcKO) results in mice with severe hypoplasia of the neocortex and no hippocampus or cerebellum. In the developing NcKO brain, RGCs lose their polarity following the disruption of AJCs and exhibit reduced proliferation, increased differentiation, and increased apoptosis. SNAP23 and its partner SNAREs, VAMP8 and Syntaxin1B, are important for the localization of an AJC protein, N-cadherin, to the apical plasma membrane of RGCs. Altogether, SNARE-mediated localization of N-cadherin is essential for AJC formation and RGC polarization during brain development.
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Affiliation(s)
- Masataka Kunii
- Department of Cell Biology, Graduate School of Medicine, Osaka University, Osaka, Japan
- Laboratory of Molecular Traffic, Department of Molecular and Cellular Biology, Institute for Molecular and Cellular Regulation, Gunma University, Gunma, Japan
| | - Yuria Noguchi
- Department of Cell Biology, Graduate School of Medicine, Osaka University, Osaka, Japan
| | - Shin-ichiro Yoshimura
- Department of Cell Biology, Graduate School of Medicine, Osaka University, Osaka, Japan
| | - Satoshi Kanda
- Department of Cell Biology, Graduate School of Medicine, Osaka University, Osaka, Japan
| | - Tomohiko Iwano
- Department of Anatomy and Cell Biology, Graduate School of Medicine, University of Yamanashi, Yamanashi, Japan
| | - Erda Avriyanti
- Department of Cell Biology, Graduate School of Medicine, Osaka University, Osaka, Japan
- Department of Dermatology and Venereology, Faculty of Medicine, Padjadjaran University, Bandung, Indonesia
| | - Nur Atik
- Department of Cell Biology, Graduate School of Medicine, Osaka University, Osaka, Japan
- Department of Biomedical Sciences, Faculty of Medicine, Padjadjaran University, Bandung, Indonesia
| | - Takashi Sato
- Laboratory of Developmental Biology and Metabolism, Department of Molecular Medicine, Institute for Molecular and Cellular Regulation, Gunma University, Gunma, Japan
| | - Ken Sato
- Laboratory of Molecular Traffic, Department of Molecular and Cellular Biology, Institute for Molecular and Cellular Regulation, Gunma University, Gunma, Japan
| | | | - Akihiro Harada
- Department of Cell Biology, Graduate School of Medicine, Osaka University, Osaka, Japan
- Laboratory of Molecular Traffic, Department of Molecular and Cellular Biology, Institute for Molecular and Cellular Regulation, Gunma University, Gunma, Japan
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11
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van Berkel AA, Santos TC, Shaweis H, van Weering JRT, Toonen RF, Verhage M. Loss of MUNC18-1 leads to retrograde transport defects in neurons. J Neurochem 2020; 157:450-466. [PMID: 33259669 PMCID: PMC8247427 DOI: 10.1111/jnc.15256] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2020] [Revised: 11/24/2020] [Accepted: 11/26/2020] [Indexed: 12/11/2022]
Abstract
Loss of the exocytic Sec1/MUNC18 protein MUNC18-1 or its target-SNARE partners SNAP25 and syntaxin-1 results in rapid, cell-autonomous and unexplained neurodegeneration, which is independent of their known role in synaptic vesicle exocytosis. cis-Golgi abnormalities are the earliest cellular phenotypes before degeneration occurs. Here, we investigated whether loss of MUNC18-1 causes defects in intracellular membrane transport pathways in primary murine neurons that may explain neurodegeneration. Electron, confocal and super resolution microscopy confirmed that loss of MUNC18-1 expression results in a smaller cis-Golgi. In addition, we now show that medial-Golgi and the trans-Golgi Network are also affected. However, stacking and cisternae ultrastructure of the Golgi were normal. Overall, ultrastructure of null mutant neurons was remarkably normal just hours before cell death occurred. By synchronizing protein trafficking by conditional cargo retention in the endoplasmic reticulum using selective hooks (RUSH) and immunocytochemistry, we show that anterograde Endoplasmic Reticulum-to-Golgi and Golgi exit of endogenous and exogenous proteins were normal. In contrast, loss of MUNC18-1 caused reduced retrograde Cholera Toxin B-subunit transport from the plasma membrane to the Golgi. In addition, MUNC18-1-deficiency resulted in abnormalities in retrograde TrkB trafficking in an antibody uptake assay. We conclude that MUNC18-1 deficient neurons have normal anterograde but reduced retrograde transport to the Golgi. The impairments in retrograde pathways suggest a role of MUNC18-1 in endosomal SNARE-dependent fusion and provide a plausible explanation for the observed Golgi abnormalities and cell death in MUNC18-1 deficient neurons.
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Affiliation(s)
- Annemiek A van Berkel
- Department of Clinical Genetics, Center for Neurogenomics and Cognitive Research (CNCR), University Medical Center Amsterdam, Amsterdam, The Netherlands.,Department of Functional Genomics, Center for Neurogenomics and Cognitive Research (CNCR), VU University Amsterdam, Amsterdam, The Netherlands
| | - Tatiana C Santos
- Department of Functional Genomics, Center for Neurogenomics and Cognitive Research (CNCR), VU University Amsterdam, Amsterdam, The Netherlands
| | - Hesho Shaweis
- Department of Functional Genomics, Center for Neurogenomics and Cognitive Research (CNCR), VU University Amsterdam, Amsterdam, The Netherlands
| | - Jan R T van Weering
- Department of Clinical Genetics, Center for Neurogenomics and Cognitive Research (CNCR), University Medical Center Amsterdam, Amsterdam, The Netherlands
| | - Ruud F Toonen
- Department of Functional Genomics, Center for Neurogenomics and Cognitive Research (CNCR), VU University Amsterdam, Amsterdam, The Netherlands
| | - Matthijs Verhage
- Department of Clinical Genetics, Center for Neurogenomics and Cognitive Research (CNCR), University Medical Center Amsterdam, Amsterdam, The Netherlands.,Department of Functional Genomics, Center for Neurogenomics and Cognitive Research (CNCR), VU University Amsterdam, Amsterdam, The Netherlands
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12
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Melland H, Carr EM, Gordon SL. Disorders of synaptic vesicle fusion machinery. J Neurochem 2020; 157:130-164. [PMID: 32916768 DOI: 10.1111/jnc.15181] [Citation(s) in RCA: 38] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Revised: 08/20/2020] [Accepted: 08/26/2020] [Indexed: 12/11/2022]
Abstract
The revolution in genetic technology has ushered in a new age for our understanding of the underlying causes of neurodevelopmental, neuromuscular and neurodegenerative disorders, revealing that the presynaptic machinery governing synaptic vesicle fusion is compromised in many of these neurological disorders. This builds upon decades of research showing that disturbance to neurotransmitter release via toxins can cause acute neurological dysfunction. In this review, we focus on disorders of synaptic vesicle fusion caused either by toxic insult to the presynapse or alterations to genes encoding the key proteins that control and regulate fusion: the SNARE proteins (synaptobrevin, syntaxin-1 and SNAP-25), Munc18, Munc13, synaptotagmin, complexin, CSPα, α-synuclein, PRRT2 and tomosyn. We discuss the roles of these proteins and the cellular and molecular mechanisms underpinning neurological deficits in these disorders.
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Affiliation(s)
- Holly Melland
- The Florey Institute of Neuroscience and Mental Health, Melbourne Dementia Research Centre, The University of Melbourne, Melbourne, Vic., Australia
| | - Elysa M Carr
- The Florey Institute of Neuroscience and Mental Health, Melbourne Dementia Research Centre, The University of Melbourne, Melbourne, Vic., Australia
| | - Sarah L Gordon
- The Florey Institute of Neuroscience and Mental Health, Melbourne Dementia Research Centre, The University of Melbourne, Melbourne, Vic., Australia
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13
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Tang BL. SNAREs and developmental disorders. J Cell Physiol 2020; 236:2482-2504. [PMID: 32959907 DOI: 10.1002/jcp.30067] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2020] [Revised: 08/20/2020] [Accepted: 09/09/2020] [Indexed: 12/12/2022]
Abstract
Members of the soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) family mediate membrane fusion processes associated with vesicular trafficking and autophagy. SNAREs mediate core membrane fusion processes essential for all cells, but some SNAREs serve cell/tissue type-specific exocytic/endocytic functions, and are therefore critical for various aspects of embryonic development. Mutations or variants of their encoding genes could give rise to developmental disorders, such as those affecting the nervous system and immune system in humans. Mutations to components in the canonical synaptic vesicle fusion SNARE complex (VAMP2, STX1A/B, and SNAP25) and a key regulator of SNARE complex formation MUNC18-1, produce variant phenotypes of autism, intellectual disability, movement disorders, and epilepsy. STX11 and MUNC18-2 mutations underlie 2 subtypes of familial hemophagocytic lymphohistiocytosis. STX3 mutations contribute to variant microvillus inclusion disease. Chromosomal microdeletions involving STX16 play a role in pseudohypoparathyroidism type IB associated with abnormal imprinting of the GNAS complex locus. In this short review, I discuss these and other SNARE gene mutations and variants that are known to be associated with a variety developmental disorders, with a focus on their underlying cellular and molecular pathological basis deciphered through disease modeling. Possible pathogenic potentials of other SNAREs whose variants could be disease predisposing are also speculated upon.
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Affiliation(s)
- Bor L Tang
- Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
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14
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Vardar G, Gerth F, Schmitt XJ, Rautenstrauch P, Trimbuch T, Schubert J, Lerche H, Rosenmund C, Freund C. Epilepsy-causing STX1B mutations translate altered protein functions into distinct phenotypes in mouse neurons. Brain 2020; 143:2119-2138. [DOI: 10.1093/brain/awaa151] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2018] [Revised: 03/05/2020] [Accepted: 03/25/2020] [Indexed: 01/21/2023] Open
Abstract
AbstractSyntaxin 1B (STX1B) is a core component of the N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) complex that is critical for the exocytosis of synaptic vesicles in the presynapse. SNARE-mediated vesicle fusion is assisted by Munc18-1, which recruits STX1B in the auto-inhibited conformation, while Munc13 catalyses the fast and efficient pairing of helices during SNARE complex formation. Mutations within the STX1B gene are associated with epilepsy. Here we analysed three STX1B mutations by biochemical and electrophysiological means. These three paradigmatic mutations cause epilepsy syndromes of different severity, from benign fever-associated seizures in childhood to severe epileptic encephalopathies. An insertion/deletion (K45/RMCIE, L46M) mutation (STX1BInDel), causing mild epilepsy and located in the early helical Habc domain, leads to an unfolded protein unable to sustain neurotransmission. STX1BG226R, causing epileptic encephalopathies, strongly compromises the interaction with Munc18-1 and reduces expression of both proteins, the size of the readily releasable pool of vesicles, and Ca2+-triggered neurotransmitter release when expressed in STX1-null neurons. The mutation STX1BV216E, also causing epileptic encephalopathies, only slightly diminishes Munc18-1 and Munc13 interactions, but leads to enhanced fusogenicity and increased vesicular release probability, also in STX1-null neurons. Even though the synaptic output remained unchanged in excitatory hippocampal STX1B+/− neurons exogenously expressing STX1B mutants, the manifestation of clear and distinct molecular disease mechanisms by these mutants suggest that certain forms of epilepsies can be conceptualized by assigning mutations to structurally sensitive regions of the STX1B−Munc18-1 interface, translating into distinct neurophysiological phenotypes.
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Affiliation(s)
- Gülçin Vardar
- Institute of Neurophysiology, Charité-Universitätsmedizin Berlin, Germany
| | - Fabian Gerth
- Laboratory of Protein Biochemistry, Institute for Chemistry and Biochemistry, Freie Universität Berlin, Germany
| | - Xiao Jakob Schmitt
- Laboratory of Protein Biochemistry, Institute for Chemistry and Biochemistry, Freie Universität Berlin, Germany
| | - Pia Rautenstrauch
- Laboratory of Protein Biochemistry, Institute for Chemistry and Biochemistry, Freie Universität Berlin, Germany
| | - Thorsten Trimbuch
- Institute of Neurophysiology, Charité-Universitätsmedizin Berlin, Germany
| | - Julian Schubert
- Department of Neurology and Epileptology, Hertie Institute for Clinical Brain Research, University of Tübingen, Germany
| | - Holger Lerche
- Department of Neurology and Epileptology, Hertie Institute for Clinical Brain Research, University of Tübingen, Germany
| | | | - Christian Freund
- Laboratory of Protein Biochemistry, Institute for Chemistry and Biochemistry, Freie Universität Berlin, Germany
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15
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Verhage M, Sørensen JB. SNAREopathies: Diversity in Mechanisms and Symptoms. Neuron 2020; 107:22-37. [PMID: 32559416 DOI: 10.1016/j.neuron.2020.05.036] [Citation(s) in RCA: 57] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2020] [Revised: 04/29/2020] [Accepted: 05/26/2020] [Indexed: 12/14/2022]
Abstract
Neuronal SNAREs and their key regulators together drive synaptic vesicle exocytosis and synaptic transmission as a single integrated membrane fusion machine. Human pathogenic mutations have now been reported for all eight core components, but patients are diagnosed with very different neurodevelopmental syndromes. We propose to unify these syndromes, based on etiology and mechanism, as "SNAREopathies." Here, we review the strikingly diverse clinical phenomenology and disease severity and the also remarkably diverse genetic mechanisms. We argue that disease severity generally scales with functional redundancy and, conversely, that the large effect of mutations in some SNARE genes is the price paid for extensive integration and exceptional specialization. Finally, we discuss how subtle differences in components being rate limiting in different types of neurons helps to explain the main symptoms.
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Affiliation(s)
- Matthijs Verhage
- Department of Functional Genomics, Vrije Universiteit (VU) Amsterdam, De Boelelaan 1085, Amsterdam 1081 HV, the Netherlands; Department of Clinical Genetics, UMC Amsterdam, De Boelelaan 1085, Amsterdam 1081 HV, the Netherlands.
| | - Jakob B Sørensen
- Department of Neuroscience, University of Copenhagen, 2200 Copenhagen N, Denmark.
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16
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Cieślik M, Gąssowska-Dobrowolska M, Jęśko H, Czapski GA, Wilkaniec A, Zawadzka A, Dominiak A, Polowy R, Filipkowski RK, Boguszewski PM, Gewartowska M, Frontczak-Baniewicz M, Sun GY, Beversdorf DQ, Adamczyk A. Maternal Immune Activation Induces Neuroinflammation and Cortical Synaptic Deficits in the Adolescent Rat Offspring. Int J Mol Sci 2020; 21:E4097. [PMID: 32521803 PMCID: PMC7312084 DOI: 10.3390/ijms21114097] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2020] [Revised: 06/03/2020] [Accepted: 06/05/2020] [Indexed: 01/01/2023] Open
Abstract
Maternal immune activation (MIA), induced by infection during pregnancy, is an important risk factor for neuro-developmental disorders, such as autism. Abnormal maternal cytokine signaling may affect fetal brain development and contribute to neurobiological and behavioral changes in the offspring. Here, we examined the effect of lipopolysaccharide-induced MIA on neuro-inflammatory changes, as well as synaptic morphology and key synaptic protein level in cerebral cortex of adolescent male rat offspring. Adolescent MIA offspring showed elevated blood cytokine levels, microglial activation, increased pro-inflammatory cytokines expression and increased oxidative stress in the cerebral cortex. Moreover, pathological changes in synaptic ultrastructure of MIA offspring was detected, along with presynaptic protein deficits and down-regulation of postsynaptic scaffolding proteins. Consequently, ability to unveil MIA-induced long-term alterations in synapses structure and protein level may have consequences on postnatal behavioral changes, associated with, and predisposed to, the development of neuropsychiatric disorders.
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Affiliation(s)
- Magdalena Cieślik
- Department of Cellular Signalling, Mossakowski Medical Research Centre, Polish Academy of Sciences, Pawińskiego 5, 02-106 Warsaw, Poland; (M.G.-D.); (H.J.); (G.A.C.); (A.W.); (A.Z.)
| | - Magdalena Gąssowska-Dobrowolska
- Department of Cellular Signalling, Mossakowski Medical Research Centre, Polish Academy of Sciences, Pawińskiego 5, 02-106 Warsaw, Poland; (M.G.-D.); (H.J.); (G.A.C.); (A.W.); (A.Z.)
| | - Henryk Jęśko
- Department of Cellular Signalling, Mossakowski Medical Research Centre, Polish Academy of Sciences, Pawińskiego 5, 02-106 Warsaw, Poland; (M.G.-D.); (H.J.); (G.A.C.); (A.W.); (A.Z.)
| | - Grzegorz A. Czapski
- Department of Cellular Signalling, Mossakowski Medical Research Centre, Polish Academy of Sciences, Pawińskiego 5, 02-106 Warsaw, Poland; (M.G.-D.); (H.J.); (G.A.C.); (A.W.); (A.Z.)
| | - Anna Wilkaniec
- Department of Cellular Signalling, Mossakowski Medical Research Centre, Polish Academy of Sciences, Pawińskiego 5, 02-106 Warsaw, Poland; (M.G.-D.); (H.J.); (G.A.C.); (A.W.); (A.Z.)
| | - Aleksandra Zawadzka
- Department of Cellular Signalling, Mossakowski Medical Research Centre, Polish Academy of Sciences, Pawińskiego 5, 02-106 Warsaw, Poland; (M.G.-D.); (H.J.); (G.A.C.); (A.W.); (A.Z.)
| | - Agnieszka Dominiak
- Department of Biochemistry and Pharmacogenomics, Faculty of Pharmacy, Medical University of Warsaw, Żwirki i Wigury 61, 02-097 Warsaw, Poland;
| | - Rafał Polowy
- Behavior and Metabolism Research Laboratory, Mossakowski Medical Research Centre, Polish Academy of Sciences, Pawińskiego 5, 02-106 Warsaw, Poland; (R.P.); (R.K.F.)
| | - Robert K. Filipkowski
- Behavior and Metabolism Research Laboratory, Mossakowski Medical Research Centre, Polish Academy of Sciences, Pawińskiego 5, 02-106 Warsaw, Poland; (R.P.); (R.K.F.)
| | - Paweł M. Boguszewski
- Laboratory of Animal Models, Neurobiology Center, Nencki Institute of Experimental Biology, Polish Academy of Sciences, Pasteur 3, 02-093 Warsaw, Poland;
| | - Magdalena Gewartowska
- Electron Microscopy Platform, Mossakowski Medical Research Centre, Polish Academy of Sciences, Pawińskiego 5, 02-106 Warsaw, Poland; (M.G.); (M.F.-B.)
| | - Małgorzata Frontczak-Baniewicz
- Electron Microscopy Platform, Mossakowski Medical Research Centre, Polish Academy of Sciences, Pawińskiego 5, 02-106 Warsaw, Poland; (M.G.); (M.F.-B.)
| | - Grace Y. Sun
- Department of Biochemistry, University of Missouri, 117 Schweitzer Hall, Columbia, MO 65201, USA;
| | - David Q. Beversdorf
- Departments of Radiology, Neurology, and Psychological Sciences, William and Nancy Thompson Endowed Chair in Radiology, DC069.10, One Hospital Drive, University of Missouri, Columbia, MO 65211, USA;
| | - Agata Adamczyk
- Department of Cellular Signalling, Mossakowski Medical Research Centre, Polish Academy of Sciences, Pawińskiego 5, 02-106 Warsaw, Poland; (M.G.-D.); (H.J.); (G.A.C.); (A.W.); (A.Z.)
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17
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Zaqout S, Blaesius K, Wu YJ, Ott S, Kraemer N, Becker LL, Rosário M, Rosenmund C, Strauss U, Kaindl AM. Altered inhibition and excitation in neocortical circuits in congenital microcephaly. Neurobiol Dis 2019; 129:130-143. [PMID: 31102767 DOI: 10.1016/j.nbd.2019.05.008] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2018] [Revised: 04/15/2019] [Accepted: 05/11/2019] [Indexed: 02/06/2023] Open
Abstract
Congenital microcephaly is highly associated with intellectual disability. Features of autosomal recessive primary microcephaly subtype 3 (MCPH3) also include hyperactivity and seizures. The disease is caused by biallelic mutations in the Cyclin-dependent kinase 5 regulatory subunit-associated protein 2 gene CDK5RAP2. In the mouse, Cdk5rap2 mutations similar to the human condition result in reduced brain size and a strikingly thin neocortex already at early stages of neurogenesis that persists through adulthood. The microcephaly phenotype in MCPH arises from a neural stem cell proliferation defect. Here, we report a novel role for Cdk5rap2 in the regulation of dendritic development and synaptogenesis of neocortical layer 2/3 pyramidal neurons. Cdk5rap2-deficient murine neurons show poorly branched dendritic arbors and an increased density of immature thin spines and glutamatergic synapses in vivo. Moreover, the excitatory drive is enhanced in ex vivo brain slice preparations of Cdk5rap2 mutant mice. Concurrently, we show that pyramidal neurons receive fewer inhibitory inputs. Together, these findings point towards a shift in the excitation - inhibition balance towards excitation in Cdk5rap2 mutant mice. Thus, MCPH3 is associated not only with a neural progenitor proliferation defect but also with altered function of postmitotic neurons and hence with altered connectivity.
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Affiliation(s)
- Sami Zaqout
- Charité - Universitätsmedizin Berlin, Institute of Cell- and Neurobiology, Charitéplatz 1, 10117 Berlin, Germany; Charité - Universitätsmedizin Berlin, Center for Chronically Sick Children (Sozialpädiatrisches Zentrum, SPZ), Augustenburger Platz 1, 13353 Berlin, Germany; Charité - Universitätsmedizin Berlin, Department of Pediatric Neurology, Augustenburger Platz 1, 13353 Berlin, Germany; Berlin Institute of Health (BIH), Anna-Louisa-Karsch Strasse 2, 10178 Berlin, Germany
| | - Kathrin Blaesius
- Charité - Universitätsmedizin Berlin, Institute of Cell- and Neurobiology, Charitéplatz 1, 10117 Berlin, Germany; Charité - Universitätsmedizin Berlin, Center for Chronically Sick Children (Sozialpädiatrisches Zentrum, SPZ), Augustenburger Platz 1, 13353 Berlin, Germany; Charité - Universitätsmedizin Berlin, Department of Pediatric Neurology, Augustenburger Platz 1, 13353 Berlin, Germany; Berlin Institute of Health (BIH), Anna-Louisa-Karsch Strasse 2, 10178 Berlin, Germany
| | - Yuan-Ju Wu
- Charité - Universitätsmedizin Berlin, NeuroCure, Charitéplatz 1, 10117 Berlin, Germany
| | - Stefanie Ott
- Charité - Universitätsmedizin Berlin, Institute of Cell- and Neurobiology, Charitéplatz 1, 10117 Berlin, Germany
| | - Nadine Kraemer
- Charité - Universitätsmedizin Berlin, Institute of Cell- and Neurobiology, Charitéplatz 1, 10117 Berlin, Germany; Charité - Universitätsmedizin Berlin, Center for Chronically Sick Children (Sozialpädiatrisches Zentrum, SPZ), Augustenburger Platz 1, 13353 Berlin, Germany; Charité - Universitätsmedizin Berlin, Department of Pediatric Neurology, Augustenburger Platz 1, 13353 Berlin, Germany
| | - Lena-Luise Becker
- Charité - Universitätsmedizin Berlin, Institute of Cell- and Neurobiology, Charitéplatz 1, 10117 Berlin, Germany; Charité - Universitätsmedizin Berlin, Center for Chronically Sick Children (Sozialpädiatrisches Zentrum, SPZ), Augustenburger Platz 1, 13353 Berlin, Germany; Charité - Universitätsmedizin Berlin, Department of Pediatric Neurology, Augustenburger Platz 1, 13353 Berlin, Germany
| | - Marta Rosário
- Charité - Universitätsmedizin Berlin, Institute of Cell- and Neurobiology, Charitéplatz 1, 10117 Berlin, Germany
| | - Christian Rosenmund
- Berlin Institute of Health (BIH), Anna-Louisa-Karsch Strasse 2, 10178 Berlin, Germany; Charité - Universitätsmedizin Berlin, NeuroCure, Charitéplatz 1, 10117 Berlin, Germany; Charité - Universitätsmedizin Berlin, Institute of Neurophysiology, Charitéplatz 1, 10117 Berlin, Germany
| | - Ulf Strauss
- Charité - Universitätsmedizin Berlin, Institute of Cell- and Neurobiology, Charitéplatz 1, 10117 Berlin, Germany
| | - Angela M Kaindl
- Charité - Universitätsmedizin Berlin, Institute of Cell- and Neurobiology, Charitéplatz 1, 10117 Berlin, Germany; Charité - Universitätsmedizin Berlin, Center for Chronically Sick Children (Sozialpädiatrisches Zentrum, SPZ), Augustenburger Platz 1, 13353 Berlin, Germany; Charité - Universitätsmedizin Berlin, Department of Pediatric Neurology, Augustenburger Platz 1, 13353 Berlin, Germany; Berlin Institute of Health (BIH), Anna-Louisa-Karsch Strasse 2, 10178 Berlin, Germany.
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18
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Monteggia LM, Lin PY, Adachi M, Kavalali ET. Behavioral Analysis of SNAP-25 and Synaptobrevin-2 Haploinsufficiency in Mice. Neuroscience 2018; 420:129-135. [PMID: 30144509 DOI: 10.1016/j.neuroscience.2018.08.014] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2018] [Revised: 08/11/2018] [Accepted: 08/13/2018] [Indexed: 10/28/2022]
Abstract
In central synapses, synaptobrevin-2 (also called VAMP-2) is the predominant synaptic vesicle SNARE protein that interacts with the plasma membrane SNAREs, SNAP-25 and syntaxin-1 to execute exocytosis. Mice deficient in synaptobrevin-2 or SNAP-25 show embryonic lethality, which precludes investigation of the complete loss-of-function of these proteins in the adult nervous system. However, mice that carry heterozygous null mutations survive into adulthood and are fertile. In order to elucidate how loss-of-function mutations in these proteins may result in human disease phenotypes it is important to develop bona fide animal models. Therefore, given the importance of these two critical SNAREs in central synaptic transmission and their association with several neurological or neuropsychiatric disorders, we performed a comprehensive behavioral analysis of SNAP-25 heterozygous null (SNAP-25+/-) mice as well as the synaptobrevin-2 heterozygous null (+/-) mice. This analysis revealed only mild phenotypes, SNAP-25 (+/-) mice exhibited marked hypoactivity, whereas synaptobrevin-2 (+/-) mice showed enhanced performance on the rotarod. The two mouse lines did not manifest significant deficits in anxiety-related behaviors, learning and memory measures, or prepulse inhibition. The rather mild behavioral deficits indicate that these key proteins, SNAP25 and synaptobrevin-2, are expressed in excess to circumvent the impact of potential fluctuations in expression levels on nervous system function.
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Affiliation(s)
- Lisa M Monteggia
- Department of Neuroscience, The University of Texas Southwestern Medical Center, Dallas, TX 75390-9111, USA.
| | - Pei-Yi Lin
- Department of Neuroscience, The University of Texas Southwestern Medical Center, Dallas, TX 75390-9111, USA
| | - Megumi Adachi
- Department of Neuroscience, The University of Texas Southwestern Medical Center, Dallas, TX 75390-9111, USA
| | - Ege T Kavalali
- Department of Neuroscience, The University of Texas Southwestern Medical Center, Dallas, TX 75390-9111, USA.
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20
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Ma H, Feng S, Deng X, Wang L, Zeng S, Wang C, Ma X, Sun H, Chen R, Du S, Mao J, Zhang X, Ma C, Jiang H, Zhang L, Tang B, Liu JY. APRRT2variant in a Chinese family with paroxysmal kinesigenic dyskinesia and benign familial infantile seizures results in loss of interaction withSTX1B. Epilepsia 2018; 59:1621-1630. [DOI: 10.1111/epi.14511] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2017] [Accepted: 06/14/2018] [Indexed: 01/03/2023]
Affiliation(s)
- Hongying Ma
- Key Laboratory of Molecular Biophysics of the Ministry of Education; Center for Human Genome Research; College of Life Science and Technology; Huazhong University of Science and Technology; Wuhan China
| | - Shenglei Feng
- Key Laboratory of Molecular Biophysics of the Ministry of Education; Center for Human Genome Research; College of Life Science and Technology; Huazhong University of Science and Technology; Wuhan China
| | - Xuejun Deng
- Department of Neurology; Union Hospital of Huazhong University of Science and Technology; Wuhan China
| | - Li Wang
- Key Laboratory of Molecular Biophysics of the Ministry of Education; Center for Human Genome Research; College of Life Science and Technology; Huazhong University of Science and Technology; Wuhan China
| | - Sheng Zeng
- Department of Neurology, Xiangya Hospital; Key Laboratory of Hunan Province in Neurodegenerative Disorders; Central South University; Changsha China
| | - Cheng Wang
- Key Laboratory of Molecular Biophysics of the Ministry of Education; Center for Human Genome Research; College of Life Science and Technology; Huazhong University of Science and Technology; Wuhan China
| | - Xixiang Ma
- Key Laboratory of Molecular Biophysics of the Ministry of Education; Center for Human Genome Research; College of Life Science and Technology; Huazhong University of Science and Technology; Wuhan China
| | - Hao Sun
- Key Laboratory of Molecular Biophysics of the Ministry of Education; Center for Human Genome Research; College of Life Science and Technology; Huazhong University of Science and Technology; Wuhan China
| | - Rui Chen
- Key Laboratory of Molecular Biophysics of the Ministry of Education; Center for Human Genome Research; College of Life Science and Technology; Huazhong University of Science and Technology; Wuhan China
| | - Shiyue Du
- Key Laboratory of Molecular Biophysics of the Ministry of Education; Center for Human Genome Research; College of Life Science and Technology; Huazhong University of Science and Technology; Wuhan China
| | - Jinglin Mao
- Key Laboratory of Molecular Biophysics of the Ministry of Education; Center for Human Genome Research; College of Life Science and Technology; Huazhong University of Science and Technology; Wuhan China
| | - Xianwei Zhang
- Department of Anesthesiology; Tongji Hospital of Huazhong University of Science and Technology; Wuhan China
| | - Cong Ma
- Key Laboratory of Molecular Biophysics of the Ministry of Education; Center for Human Genome Research; College of Life Science and Technology; Huazhong University of Science and Technology; Wuhan China
| | - Hong Jiang
- Department of Neurology, Xiangya Hospital; Key Laboratory of Hunan Province in Neurodegenerative Disorders; Central South University; Changsha China
| | - Luoying Zhang
- Key Laboratory of Molecular Biophysics of the Ministry of Education; Center for Human Genome Research; College of Life Science and Technology; Huazhong University of Science and Technology; Wuhan China
| | - Beisha Tang
- Department of Neurology, Xiangya Hospital; Key Laboratory of Hunan Province in Neurodegenerative Disorders; Central South University; Changsha China
| | - Jing Yu Liu
- Key Laboratory of Molecular Biophysics of the Ministry of Education; Center for Human Genome Research; College of Life Science and Technology; Huazhong University of Science and Technology; Wuhan China
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21
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Ros O, Barrecheguren PJ, Cotrufo T, Schaettin M, Roselló-Busquets C, Vílchez-Acosta A, Hernaiz-Llorens M, Martínez-Marmol R, Ulloa F, Stoeckli ET, Araújo SJ, Soriano E. A conserved role for Syntaxin-1 in pre- and post-commissural midline axonal guidance in fly, chick, and mouse. PLoS Genet 2018; 14:e1007432. [PMID: 29912942 PMCID: PMC6029812 DOI: 10.1371/journal.pgen.1007432] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2017] [Revised: 07/03/2018] [Accepted: 05/18/2018] [Indexed: 02/03/2023] Open
Abstract
Axonal growth and guidance rely on correct growth cone responses to guidance cues. Unlike the signaling cascades that link axonal growth to cytoskeletal dynamics, little is known about the crosstalk mechanisms between guidance and membrane dynamics and turnover. Recent studies indicate that whereas axonal attraction requires exocytosis, chemorepulsion relies on endocytosis. Indeed, our own studies have shown that Netrin-1/Deleted in Colorectal Cancer (DCC) signaling triggers exocytosis through the SNARE Syntaxin-1 (STX1). However, limited in vivo evidence is available about the role of SNARE proteins in axonal guidance. To address this issue, here we systematically deleted SNARE genes in three species. We show that loss-of-function of STX1 results in pre- and post-commissural axonal guidance defects in the midline of fly, chick, and mouse embryos. Inactivation of VAMP2, Ti-VAMP, and SNAP25 led to additional abnormalities in axonal guidance. We also confirmed that STX1 loss-of-function results in reduced sensitivity of commissural axons to Slit-2 and Netrin-1. Finally, genetic interaction studies in Drosophila show that STX1 interacts with both the Netrin-1/DCC and Robo/Slit pathways. Our data provide evidence of an evolutionarily conserved role of STX1 and SNARE proteins in midline axonal guidance in vivo, by regulating both pre- and post-commissural guidance mechanisms. Syntaxin-1 is a core factor in tethering synaptic vesicles and mediating their fusion to the cell membrane at the synapse. Thus, Syntaxin-1 mediates neurotransmission in the adult nervous system. Here we show that this protein is also involved in axonal guidance in the CNS of vertebrates and invertebrates during the development of the nervous system: our systematic analysis of the phenotypes in the nervous system midline of fly, chick, and mouse embryos mutant for Syntaxin-1 unveils an evolutionarily conserved role for this protein in midline axonal guidance. Further, we also dissect the contribution of other proteins regulating neuronal exocytosis in axonal development. We propose that the coupling of the guidance molecule machinery to proteins that regulate exocytosis is a general mechanism linking chemotropism to axonal growth.
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Affiliation(s)
- Oriol Ros
- Department of Cell Biology, Physiology and Immunology, Faculty of Biology and Institute of Neurosciences, University of Barcelona, Barcelona, Spain
- Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), ISCIII, Madrid, Spain
| | - Pablo José Barrecheguren
- Department of Cell Biology, Physiology and Immunology, Faculty of Biology and Institute of Neurosciences, University of Barcelona, Barcelona, Spain
- Institut de Recerca Biomedica de Barcelona (IRB Barcelona), Parc Cientific de Barcelona, Barcelona, Spain
| | - Tiziana Cotrufo
- Department of Cell Biology, Physiology and Immunology, Faculty of Biology and Institute of Neurosciences, University of Barcelona, Barcelona, Spain
- Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), ISCIII, Madrid, Spain
| | - Martina Schaettin
- Institute of Molecular Life Sciences and Neuroscience Center Zurich, University of Zurich, Zurich, Switzerland
| | - Cristina Roselló-Busquets
- Department of Cell Biology, Physiology and Immunology, Faculty of Biology and Institute of Neurosciences, University of Barcelona, Barcelona, Spain
- Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), ISCIII, Madrid, Spain
| | - Alba Vílchez-Acosta
- Department of Cell Biology, Physiology and Immunology, Faculty of Biology and Institute of Neurosciences, University of Barcelona, Barcelona, Spain
- Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), ISCIII, Madrid, Spain
| | - Marc Hernaiz-Llorens
- Department of Cell Biology, Physiology and Immunology, Faculty of Biology and Institute of Neurosciences, University of Barcelona, Barcelona, Spain
- Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), ISCIII, Madrid, Spain
| | - Ramón Martínez-Marmol
- Department of Cell Biology, Physiology and Immunology, Faculty of Biology and Institute of Neurosciences, University of Barcelona, Barcelona, Spain
- Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), ISCIII, Madrid, Spain
| | - Fausto Ulloa
- Department of Cell Biology, Physiology and Immunology, Faculty of Biology and Institute of Neurosciences, University of Barcelona, Barcelona, Spain
- Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), ISCIII, Madrid, Spain
| | - Esther T. Stoeckli
- Institute of Molecular Life Sciences and Neuroscience Center Zurich, University of Zurich, Zurich, Switzerland
- * E-mail: (ETS); (SJA); (ES)
| | - Sofia J. Araújo
- Institut de Recerca Biomedica de Barcelona (IRB Barcelona), Parc Cientific de Barcelona, Barcelona, Spain
- Institut de Biologia Molecular de Barcelona (IBMB-CSIC), Parc Cientific de Barcelona, Barcelona, Spain
- Department of Genetics, Microbiology and Statistics, Faculty of Biology, University of Barcelona, Barcelona, Spain
- * E-mail: (ETS); (SJA); (ES)
| | - Eduardo Soriano
- Department of Cell Biology, Physiology and Immunology, Faculty of Biology and Institute of Neurosciences, University of Barcelona, Barcelona, Spain
- Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), ISCIII, Madrid, Spain
- Vall d´Hebron Institute of Research (VHIR), Barcelona, Spain
- Institució Catalana de Recerca i Estudis Avançats (ICREA), Barcelona, Spain
- * E-mail: (ETS); (SJA); (ES)
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Tejero R, Lopez-Manzaneda M, Arumugam S, Tabares L. Synaptotagmin-2, and -1, linked to neurotransmission impairment and vulnerability in Spinal Muscular Atrophy. Hum Mol Genet 2018; 25:4703-4716. [PMID: 28173138 DOI: 10.1093/hmg/ddw297] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2016] [Revised: 08/22/2016] [Accepted: 08/23/2016] [Indexed: 01/19/2023] Open
Abstract
Spinal muscular atrophy (SMA) is the most frequent genetic cause of infant mortality. The disease is characterized by progressive muscle weakness and paralysis of axial and proximal limb muscles. It is caused by homozygous loss or mutation of the SMN1 gene, which codes for the Survival Motor Neuron (SMN) protein. In mouse models of the disease, neurotransmitter release is greatly impaired, but the molecular mechanisms of the synaptic dysfunction and the basis of the selective muscle vulnerability are unknown. In the present study, we investigated these open questions by comparing the molecular and functional properties of nerve terminals in severely and mildly affected muscles in the SMNΔ7 mouse model. We discovered that synaptotagmin-1 (Syt1) was developmentally downregulated in nerve terminals of highly affected muscles but not in low vulnerable muscles. Additionally, the expression levels of synaptotagmin-2 (Syt2), and its interacting protein, synaptic vesicle protein 2 (SV2) B, were reduced in proportion to the degree of muscle vulnerability while other synaptic proteins, such as syntaxin-1B (Stx1B) and synaptotagmin-7 (Syt7), were not affected. Consistently with the extremely low levels of both Syt-isoforms, and SV2B, in most affected neuromuscular synapses, the functional analysis of neurotransmission revealed highly reduced evoked release, altered short-term plasticity, low release probability, and inability to modulate normally the number of functional release sites. Together, we propose that the strong reduction of Syt2 and SV2B are key factors of the functional synaptic alteration and that the physiological downregulation of Syt1 plays a determinant role in muscle vulnerability in SMA.
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Affiliation(s)
- Rocío Tejero
- Department of Medical Physiology and Biophysics, School of Medicine, University of Seville, Avda. Sánchez Pizjuán, 4. 41009 Seville, Spain
| | - Mario Lopez-Manzaneda
- Department of Medical Physiology and Biophysics, School of Medicine, University of Seville, Avda. Sánchez Pizjuán, 4. 41009 Seville, Spain
| | - Saravanan Arumugam
- Department of Medical Physiology and Biophysics, School of Medicine, University of Seville, Avda. Sánchez Pizjuán, 4. 41009 Seville, Spain
| | - Lucía Tabares
- Department of Medical Physiology and Biophysics, School of Medicine, University of Seville, Avda. Sánchez Pizjuán, 4. 41009 Seville, Spain
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Ulloa F, Cotrufo T, Ricolo D, Soriano E, Araújo SJ. SNARE complex in axonal guidance and neuroregeneration. Neural Regen Res 2018; 13:386-392. [PMID: 29623913 PMCID: PMC5900491 DOI: 10.4103/1673-5374.228710] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
Through complex mechanisms that guide axons to the appropriate routes towards their targets, axonal growth and guidance lead to neuronal system formation. These mechanisms establish the synaptic circuitry necessary for the optimal performance of the nervous system in all organisms. Damage to these networks can be repaired by neuroregenerative processes which in turn can re-establish synapses between injured axons and postsynaptic terminals. Both axonal growth and guidance and the neuroregenerative response rely on correct axonal growth and growth cone responses to guidance cues as well as correct synapses with appropriate targets. With this in mind, parallels can be drawn between axonal regeneration and processes occurring during embryonic nervous system development. However, when studying parallels between axonal development and regeneration many questions still arise; mainly, how do axons grow and synapse with their targets and how do they repair their membranes, grow and orchestrate regenerative responses after injury. Major players in the cellular and molecular processes that lead to growth cone development and movement during embryonic development are the Soluble N-ethylamaleimide Sensitive Factor (NSF) Attachment Protein Receptor (SNARE) proteins, which have been shown to be involved in axonal growth and guidance. Their involvement in axonal growth, guidance and neuroregeneration is of foremost importance, due to their roles in vesicle and membrane trafficking events. Here, we review the recent literature on the involvement of SNARE proteins in axonal growth and guidance during embryonic development and neuroregeneration.
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Affiliation(s)
- Fausto Ulloa
- Department of Cell Biology, Physiology and Immunology, School of Biology, and Institute of Neurosciences, University of Barcelona, Barcelona; Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Instituto de Salud Carlos III (ISCIII), Madrid, Spain
| | - Tiziana Cotrufo
- Department of Cell Biology, Physiology and Immunology, School of Biology, and Institute of Neurosciences, University of Barcelona, Barcelona; Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Instituto de Salud Carlos III (ISCIII), Madrid, Spain
| | - Delia Ricolo
- Institut de Biologia Molecular de Barcelona (IBMB-CSIC), Parc Cientific de Barcelona; Department of Genetics, Microbiology and Statistics, School of Biology, University of Barcelona, Barcelona, Spain
| | - Eduardo Soriano
- Department of Cell Biology, Physiology and Immunology, School of Biology, and Institute of Neurosciences, University of Barcelona, Barcelona; Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Instituto de Salud Carlos III (ISCIII), Madrid; Vall d´Hebron Institut de Recerca (VHIR), Barcelona, Spain
| | - Sofia J Araújo
- Institut de Biologia Molecular de Barcelona (IBMB-CSIC), Parc Cientific de Barcelona; Department of Genetics, Microbiology and Statistics, School of Biology, University of Barcelona, Barcelona, Spain
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Carle S, Pirazzini M, Rossetto O, Barth H, Montecucco C. High Conservation of Tetanus and Botulinum Neurotoxins Cleavage Sites on Human SNARE Proteins Suggests That These Pathogens Exerted Little or No Evolutionary Pressure on Humans. Toxins (Basel) 2017; 9:toxins9120404. [PMID: 29257047 PMCID: PMC5744124 DOI: 10.3390/toxins9120404] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2017] [Revised: 12/14/2017] [Accepted: 12/15/2017] [Indexed: 01/07/2023] Open
Abstract
The Genome Aggregation Database presently contains >120,000 human genomes. We searched in this database for the presence of mutations at the sites of tetanus (TeNT) and botulinum neurotoxins (BoNTs) cleavages of the three SNARE proteins: VAMP, SNAP-25 and Syntaxin. These mutations could account for some of the BoNT/A resistant patients. At the same time, this approach was aimed at testing the possibility that TeNT and BoNT may have acted as selective agents in the development of resistance to tetanus or botulism. We found that mutations of the SNARE proteins are very rare and concentrated outside the SNARE motif required for the formation of the SNARE complex involved in neuroexocytosis. No changes were found at the BoNT cleavage sites of VAMP and syntaxins and only one very rare mutation was found in the essential C-terminus region of SNAP-25, where Arg198 was replaced with a Cys residue. This is the P1’ cleavage site for BoNT/A and the P1 cleavage site for BoNT/C. We found that the Arg198Cys mutation renders SNAP-25 resistant to BoNT/A. Nonetheless, its low frequency (1.8 × 10−5) indicates that mutations of SNAP-25 at the BoNT/A cleavage site are unlikely to account for the existence of BoNT/A resistant patients. More in general, the present findings indicate that tetanus and botulinum neurotoxins have not acted as selective agents during human evolution as it appears to have been the case for tetanus in rats and chicken.
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Affiliation(s)
- Stefan Carle
- Institute of Pharmacology and Toxicology, University of Ulm Medical Center, Albert-Einstein-Allee 11, 89081 Ulm, Germany.
| | - Marco Pirazzini
- Department of Biomedical Sciences, University of Padova, Via Ugo Bassi 58/B, 35131 Padova, Italy.
| | - Ornella Rossetto
- Department of Biomedical Sciences, University of Padova, Via Ugo Bassi 58/B, 35131 Padova, Italy.
| | - Holger Barth
- Institute of Pharmacology and Toxicology, University of Ulm Medical Center, Albert-Einstein-Allee 11, 89081 Ulm, Germany.
| | - Cesare Montecucco
- Department of Biomedical Sciences, University of Padova, Via Ugo Bassi 58/B, 35131 Padova, Italy.
- Institute for Neuroscience, National Research Council, Via Ugo Bassi 58/B, 35131 Padova, Italy.
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25
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Zanetti G, Sikorra S, Rummel A, Krez N, Duregotti E, Negro S, Henke T, Rossetto O, Binz T, Pirazzini M. Botulinum neurotoxin C mutants reveal different effects of syntaxin or SNAP-25 proteolysis on neuromuscular transmission. PLoS Pathog 2017; 13:e1006567. [PMID: 28800600 PMCID: PMC5568444 DOI: 10.1371/journal.ppat.1006567] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2017] [Revised: 08/23/2017] [Accepted: 08/03/2017] [Indexed: 11/30/2022] Open
Abstract
Botulinum neurotoxin serotype C (BoNT/C) is a neuroparalytic toxin associated with outbreaks of animal botulism, particularly in birds, and is the only BoNT known to cleave two different SNARE proteins, SNAP-25 and syntaxin. BoNT/C was shown to be a good substitute for BoNT/A1 in human dystonia therapy because of its long lasting effects and absence of neuromuscular damage. Two triple mutants of BoNT/C, namely BoNT/C S51T/R52N/N53P (BoNT/C α-51) and BoNT/C L200W/M221W/I226W (BoNT/C α-3W), were recently reported to selectively cleave syntaxin and have been used here to evaluate the individual contribution of SNAP-25 and syntaxin cleavage to the effect of BoNT/C in vivo. Although BoNT/C α-51 and BoNT/C α-3W toxins cleave syntaxin with similar efficiency, we unexpectedly found also cleavage of SNAP-25, although to a lesser extent than wild type BoNT/C. Interestingly, the BoNT/C mutants exhibit reduced lethality compared to wild type toxin, a result that correlated with their residual activity against SNAP-25. In spite of this, a local injection of BoNT/C α-51 persistently impairs neuromuscular junction activity. This is due to an initial phase in which SNAP-25 cleavage causes a complete blockade of neurotransmission, and to a second phase of incomplete impairment ascribable to syntaxin cleavage. Together, these results indicate that neuroparalysis of BoNT/C at the neuromuscular junction is due to SNAP-25 cleavage, while the proteolysis of syntaxin provides a substantial, but incomplete, neuromuscular impairment. In light of this evidence, we discuss a possible clinical use of BoNT/C α-51 as a botulinum neurotoxin endowed with a wide safety margin and a long lasting effect. The seven established Botulinum Neurotoxins serotypes (BoNT/A to G) and the many BoNT subtypes, the causative agents of botulism, are the most poisonous substances known (lethal doses in the low ng/kg range). Due to their toxicological properties, BoNTs are Janus-faced toxins: potent pathogenic factors and potential bioterrorism agents as well as safe and efficacious therapeutics. BoNTs exert their neuroparalytic action by cleaving SNARE proteins, either SNAP-25 or synaptobrevin/VAMP, which mediate neurotransmitter release at the neuromuscular junction; BoNT/C is the only serotype shown to cleave SNAP-25 and syntaxin-1 in vitro. Our study shows for the first time that this parallel cleavage also occurs in vivo. By using mutated toxins reported to be syntaxin-selective, we found that SNAP-25 proteolysis at the neuromuscular junction is the key determinant of BoNT/C lethality as it completely blocks nerve-muscle transmission. Conversely, syntaxin-1 cleavage only attenuates nerve terminal activity without inactivating the synapse, leading to only a partial decrease of neuromuscular functionality. As a result, the BoNT/C mutants have dramatically reduced lethality, but still modulate neuromuscular junction activity upon intramuscular injection. This aspect is particularly relevant considering the possible use of syntaxin-specific BoNT/C derivatives to improve the present clinical utilization of BoNTs.
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Affiliation(s)
- Giulia Zanetti
- Department of Biomedical Sciences, University of Padova, Padova, Italy
| | - Stefan Sikorra
- Institut für Zellbiochemie, Medizinische Hochschule Hannover, Hannover, Germany
| | - Andreas Rummel
- Institut für Toxikologie, Medizinische Hochschule Hannover, Hannover, Germany
| | - Nadja Krez
- Institut für Toxikologie, Medizinische Hochschule Hannover, Hannover, Germany
| | - Elisa Duregotti
- Department of Biomedical Sciences, University of Padova, Padova, Italy
| | - Samuele Negro
- Department of Biomedical Sciences, University of Padova, Padova, Italy
| | - Tina Henke
- Institut für Zellbiochemie, Medizinische Hochschule Hannover, Hannover, Germany
| | - Ornella Rossetto
- Department of Biomedical Sciences, University of Padova, Padova, Italy
| | - Thomas Binz
- Institut für Zellbiochemie, Medizinische Hochschule Hannover, Hannover, Germany
| | - Marco Pirazzini
- Department of Biomedical Sciences, University of Padova, Padova, Italy
- * E-mail:
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26
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Distinct Functions of Syntaxin-1 in Neuronal Maintenance, Synaptic Vesicle Docking, and Fusion in Mouse Neurons. J Neurosci 2017; 36:7911-24. [PMID: 27466336 DOI: 10.1523/jneurosci.1314-16.2016] [Citation(s) in RCA: 65] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2016] [Accepted: 06/09/2016] [Indexed: 01/08/2023] Open
Abstract
UNLABELLED Neurotransmitter release requires the formation of soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) complexes by SNARE proteins syntaxin-1 (Stx1), synaptosomal-associated protein 25 (SNAP-25), and synaptobrevin-2 (Syb2). In mammalian systems, loss of SNAP-25 or Syb2 severely impairs neurotransmitter release; however, complete loss of function studies for Stx1 have been elusive due to the functional redundancy between Stx1 isoforms Stx1A and Stx1B and the embryonic lethality of Stx1A/1B double knock-out (DKO) mice. Here, we studied the roles of Stx1 in neuronal maintenance and neurotransmitter release in mice with constitutive or conditional deletion of Stx1B on an Stx1A-null background. Both constitutive and postnatal loss of Stx1 severely compromised neuronal viability in vivo and in vitro, indicating an obligatory role of Stx1 for maintenance of developing and mature neurons. Loss of Munc18-1, a high-affinity binding partner of Stx1, also showed severely impaired neuronal viability, but with a slower time course compared with Stx1A/1B DKO neurons, and exogenous Stx1A or Stx1B expression significantly delayed Munc18-1-dependent lethality. In addition, loss of Stx1 completely abolished fusion-competent vesicles and severely impaired vesicle docking, demonstrating its essential roles in neurotransmission. Putative partial SNARE complex assembly with the SNARE motif mutant Stx1A(AV) (A240V, V244A) was not sufficient to rescue neurotransmission despite full recovery of vesicle docking and neuronal survival. Together, these data suggest that Stx1 has independent functions in neuronal maintenance and neurotransmitter release and complete SNARE complex formation is required for vesicle fusion and priming, whereas partial SNARE complex formation is sufficient for vesicle docking and neuronal maintenance. SIGNIFICANCE STATEMENT Syntaxin-1 (Stx1) is a component of the synaptic vesicle soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) complex and is essential for neurotransmission. We present the first detailed loss-of-function characterization of the two Stx1 isoforms in central mammalian neurons. We show that Stx1 is fundamental for maintenance of developing and mature neurons and also for vesicle docking and neurotransmission. We also demonstrate that neuronal maintenance and neurotransmitter release are regulated by Stx1 through independent functions. Furthermore, we show that SNARE complex formation is required for vesicle fusion, whereas partial SNARE complex formation is sufficient for vesicle docking and neuronal maintenance. Therefore, our work provides insights into differential functions of Stx1 in neuronal maintenance and neurotransmission, with the latter explored further into its functions in vesicle docking and fusion.
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Nibbeling EAR, Delnooz CCS, de Koning TJ, Sinke RJ, Jinnah HA, Tijssen MAJ, Verbeek DS. Using the shared genetics of dystonia and ataxia to unravel their pathogenesis. Neurosci Biobehav Rev 2017; 75:22-39. [PMID: 28143763 DOI: 10.1016/j.neubiorev.2017.01.033] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2016] [Revised: 12/09/2016] [Accepted: 01/24/2017] [Indexed: 12/13/2022]
Abstract
In this review we explore the similarities between spinocerebellar ataxias and dystonias, and suggest potentially shared molecular pathways using a gene co-expression network approach. The spinocerebellar ataxias are a group of neurodegenerative disorders characterized by coordination problems caused mainly by atrophy of the cerebellum. The dystonias are another group of neurological movement disorders linked to basal ganglia dysfunction, although evidence is now pointing to cerebellar involvement as well. Our gene co-expression network approach identified 99 shared genes and showed the involvement of two major pathways: synaptic transmission and neurodevelopment. These pathways overlapped in the two disorders, with a large role for GABAergic signaling in both. The overlapping pathways may provide novel targets for disease therapies. We need to prioritize variants obtained by whole exome sequencing in the genes associated with these pathways in the search for new pathogenic variants, which can than be used to help in the genetic counseling of patients and their families.
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Affiliation(s)
- Esther A R Nibbeling
- University of Groningen, University Medical Center Groningen, Department of Genetics, Groningen, The Netherlands
| | - Cathérine C S Delnooz
- University of Groningen, University Medical Center Groningen, Department of Neurology, Groningen, The Netherlands
| | - Tom J de Koning
- University of Groningen, University Medical Center Groningen, Department of Genetics, Groningen, The Netherlands; University of Groningen, University Medical Center Groningen, Department of Neurology, Groningen, The Netherlands
| | - Richard J Sinke
- University of Groningen, University Medical Center Groningen, Department of Genetics, Groningen, The Netherlands
| | - Hyder A Jinnah
- Departments of Neurology, Human Genetics and Pediatrics, Emory Clinic, Atlanta, USA
| | - Marina A J Tijssen
- University of Groningen, University Medical Center Groningen, Department of Neurology, Groningen, The Netherlands
| | - Dineke S Verbeek
- University of Groningen, University Medical Center Groningen, Department of Genetics, Groningen, The Netherlands.
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28
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Cupertino RB, Kappel DB, Bandeira CE, Schuch JB, da Silva BS, Müller D, Bau CHD, Mota NR. SNARE complex in developmental psychiatry: neurotransmitter exocytosis and beyond. J Neural Transm (Vienna) 2016; 123:867-83. [DOI: 10.1007/s00702-016-1514-9] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2015] [Accepted: 01/20/2016] [Indexed: 12/31/2022]
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