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Ali G, Shin KC, Habbab W, Alkhadairi G, AbdelAleem A, AlShaban FA, Park Y, Stanton LW. Characterization of a loss-of-function NSF attachment protein beta mutation in monozygotic triplets affected with epilepsy and autism using cortical neurons from proband-derived and CRISPR-corrected induced pluripotent stem cell lines. Front Neurosci 2024; 17:1302470. [PMID: 38260021 PMCID: PMC10801733 DOI: 10.3389/fnins.2023.1302470] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2023] [Accepted: 12/12/2023] [Indexed: 01/24/2024] Open
Abstract
We investigated whether a homozygous recessive genetic variant of NSF attachment protein beta (NAPB) gene inherited by monozygotic triplets contributed to their phenotype of early-onset epilepsy and autism. Induced pluripotent stem cell (iPSC) lines were generated from all three probands and both parents. The NAPB genetic variation was corrected in iPSC lines from two probands by CRISPR/Cas9 gene editing. Cortical neurons were produced by directed, in vitro differentiation from all iPSC lines. These cell line-derived neurons enabled us to determine that the genetic variation in the probands causes exon skipping and complete absence of NAPB protein. Electrophysiological and transcriptomic comparisons of cortical neurons derived from parents and probands cell lines indicate that loss of NAPB function contributes to alterations in neuronal functions and likely contributed to the impaired neurodevelopment of the triplets.
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Affiliation(s)
- Gowher Ali
- Neurological Disorders Research Center, Qatar Biomedical Research Institute (QBRI), Hamad Bin Khalifa University (HBKU), Qatar Foundation, Doha, Qatar
| | - Kyung Chul Shin
- Neurological Disorders Research Center, Qatar Biomedical Research Institute (QBRI), Hamad Bin Khalifa University (HBKU), Qatar Foundation, Doha, Qatar
| | - Wesal Habbab
- Neurological Disorders Research Center, Qatar Biomedical Research Institute (QBRI), Hamad Bin Khalifa University (HBKU), Qatar Foundation, Doha, Qatar
| | - Ghaneya Alkhadairi
- Neurological Disorders Research Center, Qatar Biomedical Research Institute (QBRI), Hamad Bin Khalifa University (HBKU), Qatar Foundation, Doha, Qatar
| | - Alice AbdelAleem
- Medical Molecular Genetics Department, Human Genetics and Genome Research Institute, National Research Centre, Cairo, Egypt
| | - Fouad A. AlShaban
- Neurological Disorders Research Center, Qatar Biomedical Research Institute (QBRI), Hamad Bin Khalifa University (HBKU), Qatar Foundation, Doha, Qatar
| | - Yongsoo Park
- Neurological Disorders Research Center, Qatar Biomedical Research Institute (QBRI), Hamad Bin Khalifa University (HBKU), Qatar Foundation, Doha, Qatar
- College of Health and Life Sciences (CHLS), Hamad Bin Khalifa University (HBKU), Qatar Foundation, Doha, Qatar
| | - Lawrence W. Stanton
- Neurological Disorders Research Center, Qatar Biomedical Research Institute (QBRI), Hamad Bin Khalifa University (HBKU), Qatar Foundation, Doha, Qatar
- College of Health and Life Sciences (CHLS), Hamad Bin Khalifa University (HBKU), Qatar Foundation, Doha, Qatar
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2
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Ginebaugh SP, Badawi Y, Laghaei R, Mersky G, Wallace CJ, Tarr TB, Kaufhold C, Reddel S, Meriney SD. Simulations of active zone structure and function at mammalian NMJs predict that loss of calcium channels alone is not sufficient to replicate LEMS effects. J Neurophysiol 2023; 129:1259-1277. [PMID: 37073966 PMCID: PMC10202491 DOI: 10.1152/jn.00404.2022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2022] [Revised: 04/14/2023] [Accepted: 04/14/2023] [Indexed: 04/20/2023] Open
Abstract
Lambert-Eaton myasthenic syndrome (LEMS) is an autoimmune-mediated neuromuscular disease thought to be caused by autoantibodies against P/Q-type voltage-gated calcium channels (VGCCs), which attack and reduce the number of VGCCs within transmitter release sites (active zones; AZs) at the neuromuscular junction (NMJ), resulting in neuromuscular weakness. However, patients with LEMS also have antibodies to other neuronal proteins, and about 15% of patients with LEMS are seronegative for antibodies against VGCCs. We hypothesized that a reduction in the number of P/Q-type VGCCs alone is not sufficient to explain LEMS effects on transmitter release. Here, we used a computational model to study a variety of LEMS-mediated effects on AZ organization and transmitter release constrained by electron microscopic, pharmacological, immunohistochemical, voltage imaging, and electrophysiological observations. We show that models of healthy AZs can be modified to predict the transmitter release and short-term facilitation characteristics of LEMS and that in addition to a decrease in the number of AZ VGCCs, disruption in the organization of AZ proteins, a reduction in AZ number, a reduction in the amount of synaptotagmin, and the compensatory expression of L-type channels outside the remaining AZs are important contributors to LEMS-mediated effects on transmitter release. Furthermore, our models predict that antibody-mediated removal of synaptotagmin in combination with disruption in AZ organization alone could mimic LEMS effects without the removal of VGCCs (a seronegative model). Overall, our results suggest that LEMS pathophysiology may be caused by a collection of pathological alterations to AZs at the NMJ, rather than by a simple loss of VGCCs.NEW & NOTEWORTHY We used a computational model of the active zone (AZ) in the mammalian neuromuscular junction to investigate Lambert-Eaton myasthenic syndrome (LEMS) pathophysiology. This model suggests that disruptions in presynaptic active zone organization and protein content (particularly synaptotagmin), beyond the simple removal of presynaptic calcium channels, play an important role in LEMS pathophysiology.
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Affiliation(s)
- Scott P Ginebaugh
- Department of Neuroscience, Center for Neuroscience, University of Pittsburgh, Pittsburgh, Pennsylvania, United States
| | - Yomna Badawi
- Department of Neuroscience, Center for Neuroscience, University of Pittsburgh, Pittsburgh, Pennsylvania, United States
| | - Rozita Laghaei
- Biomedical Application Group, Pittsburgh Supercomputing Center, Carnegie Mellon University, Pittsburgh, Pennsylvania, United States
| | - Glenn Mersky
- Biomedical Application Group, Pittsburgh Supercomputing Center, Carnegie Mellon University, Pittsburgh, Pennsylvania, United States
| | - Caleb J Wallace
- Biomedical Application Group, Pittsburgh Supercomputing Center, Carnegie Mellon University, Pittsburgh, Pennsylvania, United States
| | - Tyler B Tarr
- Department of Neuroscience, Center for Neuroscience, University of Pittsburgh, Pittsburgh, Pennsylvania, United States
| | - Cassandra Kaufhold
- Department of Neuroscience, Center for Neuroscience, University of Pittsburgh, Pittsburgh, Pennsylvania, United States
| | - Stephen Reddel
- Department of Clinical Neurology, Concord Hospital, Sydney, New South Wales, Australia
| | - Stephen D Meriney
- Department of Neuroscience, Center for Neuroscience, University of Pittsburgh, Pittsburgh, Pennsylvania, United States
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3
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Brunger AT, Leitz J. The Core Complex of the Ca 2+-Triggered Presynaptic Fusion Machinery. J Mol Biol 2023; 435:167853. [PMID: 36243149 PMCID: PMC10578080 DOI: 10.1016/j.jmb.2022.167853] [Citation(s) in RCA: 15] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2022] [Revised: 09/30/2022] [Accepted: 10/03/2022] [Indexed: 11/05/2022]
Abstract
Synaptic neurotransmitter release is mediated by an orchestra of presynaptic proteins that precisely control and trigger fusion between synaptic vesicles and the neuron terminal at the active zone upon the arrival of an action potential. Critical to this process are the neuronal SNAREs (Soluble N-ethylmaleimide sensitive factor Attachment protein REceptor), the Ca2+-sensor synaptotagmin, the activator/regulator complexin, and other factors. Here, we review the interactions between the SNARE complex and synaptotagmin, with focus on the so-called primary interface between synaptotagmin and the SNARE complex that has been validated in terms of its physiological relevance. We discuss several other but less validated interfaces as well, including the so-called tripartite interface, and we discuss the pros and cons for these possible alternative interfaces. We also present new molecular dynamics simulations of the tripartite interface and new data of an inhibitor of the primary interface in a reconstituted system of synaptic vesicle fusion.
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Affiliation(s)
- Axel T Brunger
- Department of Molecular and Cellular Physiology, Stanford University, Stanford, United States; Department of Neurology and Neurological Sciences, Stanford University, Stanford, United States; Department of Structural Biology, Stanford University, Stanford, United States; Department of Photon Science, Stanford University, Stanford, United States; Howard Hughes Medical Institute, Stanford University, Stanford, United States.
| | - Jeremy Leitz
- Department of Molecular and Cellular Physiology, Stanford University, Stanford, United States; Department of Neurology and Neurological Sciences, Stanford University, Stanford, United States; Department of Structural Biology, Stanford University, Stanford, United States; Department of Photon Science, Stanford University, Stanford, United States; Howard Hughes Medical Institute, Stanford University, Stanford, United States
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4
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Pugliese A, Holland SH, Rodolico C, Lochmüller H, Spendiff S. Presynaptic Congenital Myasthenic Syndromes: Understanding Clinical Phenotypes through In vivo Models. J Neuromuscul Dis 2023; 10:731-759. [PMID: 37212067 PMCID: PMC10578258 DOI: 10.3233/jnd-221646] [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] [Accepted: 04/30/2023] [Indexed: 05/23/2023]
Abstract
Presynaptic congenital myasthenic syndromes (CMS) are a group of genetic disorders affecting the presynaptic side of the neuromuscular junctions (NMJ). They can result from a dysfunction in acetylcholine (ACh) synthesis or recycling, in its packaging into synaptic vesicles, or its subsequent release into the synaptic cleft. Other proteins involved in presynaptic endplate development and maintenance can also be impaired.Presynaptic CMS usually presents during the prenatal or neonatal period, with a severe phenotype including congenital arthrogryposis, developmental delay, and apnoeic crisis. However, milder phenotypes with proximal muscle weakness and good response to treatment have been described. Finally, many presynaptic genes are expressed in the brain, justifying the presence of additional central nervous system symptoms.Several animal models have been developed to study CMS, providing the opportunity to identify disease mechanisms and test treatment options. In this review, we describe presynaptic CMS phenotypes with a focus on in vivo models, to better understand CMS pathophysiology and define new causative genes.
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Affiliation(s)
- Alessia Pugliese
- Children’s Hospital of Eastern Ontario Research Institute, Ottawa, ON, Canada
- Department of Clinical and Experimental Medicine, University of Messina, Messina, Italy
| | - Stephen H. Holland
- Children’s Hospital of Eastern Ontario Research Institute, Ottawa, ON, Canada
- Department of Cellular and Molecular Medicine, Faculty of Medicine, University of Ottawa, Ottawa, ON, Canada
| | - Carmelo Rodolico
- Department of Clinical and Experimental Medicine, University of Messina, Messina, Italy
| | - Hanns Lochmüller
- Children’s Hospital of Eastern Ontario Research Institute, Ottawa, ON, Canada
- Department of Medicine, Division of Neurology, The Ottawa Hospital, Ottawa, ON, Canada
- Brain and Mind Research Institute, University of Ottawa, Ottawa, ON, Canada
- Department of Neuropediatrics and Muscle Disorders, Medical Center – University of Freiburg, Faculty of Medicine, Freiburg, Germany
- Centro Nacional de Análisis Genómico (CNAG-CRG), Center for Genomic Regulation, Barcelona Institute of Science and Technology (BIST), Barcelona, Catalonia, Spain
| | - Sally Spendiff
- Children’s Hospital of Eastern Ontario Research Institute, Ottawa, ON, Canada
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5
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Wang ZW, Riaz S, Niu L. Roles and Sources of Calcium in Synaptic Exocytosis. ADVANCES IN NEUROBIOLOGY 2023; 33:139-170. [PMID: 37615866 DOI: 10.1007/978-3-031-34229-5_6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/25/2023]
Abstract
Calcium ions (Ca2+) play a critical role in triggering neurotransmitter release. The rate of release is directly related to the concentration of Ca2+ at the presynaptic site, with a supralinear relationship. There are two main sources of Ca2+ that trigger synaptic vesicle fusion: influx through voltage-gated Ca2+ channels in the plasma membrane and release from the endoplasmic reticulum via ryanodine receptors. This chapter will cover the sources of Ca2+ at the presynaptic nerve terminal, the relationship between neurotransmitter release rate and Ca2+ concentration, and the mechanisms that achieve the necessary Ca2+ concentrations for triggering synaptic exocytosis at the presynaptic site.
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Affiliation(s)
- Zhao-Wen Wang
- Department of Neuroscience, University of Connecticut School of Medicine, Farmington, CT, USA.
| | - Sadaf Riaz
- Department of Neuroscience, University of Connecticut School of Medicine, Farmington, CT, USA
| | - Longgang Niu
- Department of Neuroscience, University of Connecticut School of Medicine, Farmington, CT, USA
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6
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Yu X, Wang Y. Tonotopic differentiation of presynaptic neurotransmitter-releasing machinery in the auditory brainstem during the prehearing period and its selective deficits in Fmr1 knockout mice. J Comp Neurol 2022; 530:3248-3269. [PMID: 36067267 PMCID: PMC9588645 DOI: 10.1002/cne.25406] [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: 04/13/2022] [Revised: 07/29/2022] [Accepted: 08/24/2022] [Indexed: 11/07/2022]
Abstract
Tonotopic organization is a fundamental feature of the auditory system. In the developing auditory brainstem, the ontogeny and maturation of neurotransmission progress from high to low frequencies along the tonotopic axis. To explore the underlying mechanism of this tonotopic development, we aim to determine whether the presynaptic machinery responsible for neurotransmitter release is tonotopically differentiated during development. In the current study, we examined vesicular neurotransmitter transporters and calcium sensors, two central players responsible for loading neurotransmitter into synaptic vesicles and for triggering neurotransmitter release in a calcium-dependent manner, respectively. Using immunocytochemistry, we characterized the distribution patterns of vesicular glutamate transporters (VGLUTs) 1 and 2, vesicular gamma-aminobutyric acid transporter (VGAT), and calcium sensor synaptotagmin (Syt) 1 and 2 in the developing mouse medial nucleus of the trapezoid body (MNTB). We identified tonotopic gradients of VGLUT1, VGAT, Syt1, and Syt2 in the first postnatal week, with higher protein densities in the more medial (high-frequency) portion of the MNTB. These gradients gradually flattened before the onset of hearing. In contrast, VGLUT2 was distributed relatively uniformly along the tonotopic axis during this prehearing period. In mice lacking Fragile X mental retardation protein, an mRNA-binding protein that regulates synaptic development and plasticity, progress to achieve the mature-like organization was altered for VGLUT1, Syt1, and Syt2, but not for VGAT. Together, our results identified novel organization patterns of selective presynaptic proteins in immature auditory synapses, providing a potential mechanism that may contribute to tonotopic differentiation of neurotransmission during normal and abnormal development.
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Affiliation(s)
- Xiaoyan Yu
- Program in Neuroscience, Department of Biomedical Sciences, Florida State University College of Medicine, Tallahassee, Florida, USA
| | - Yuan Wang
- Program in Neuroscience, Department of Biomedical Sciences, Florida State University College of Medicine, Tallahassee, Florida, USA
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7
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Mochida S. Mechanisms of Synaptic Vesicle Exo- and Endocytosis. Biomedicines 2022; 10:1593. [PMID: 35884898 PMCID: PMC9313035 DOI: 10.3390/biomedicines10071593] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2022] [Revised: 06/21/2022] [Accepted: 06/22/2022] [Indexed: 01/05/2023] Open
Abstract
Within 1 millisecond of action potential arrival at presynaptic terminals voltage-gated Ca2+ channels open. The Ca2+ channels are linked to synaptic vesicles which are tethered by active zone proteins. Ca2+ entrance into the active zone triggers: (1) the fusion of the vesicle and exocytosis, (2) the replenishment of the active zone with vesicles for incoming exocytosis, and (3) various types of endocytosis for vesicle reuse, dependent on the pattern of firing. These time-dependent vesicle dynamics are controlled by presynaptic Ca2+ sensor proteins, regulating active zone scaffold proteins, fusion machinery proteins, motor proteins, endocytic proteins, several enzymes, and even Ca2+ channels, following the decay of Ca2+ concentration after the action potential. Here, I summarize the Ca2+-dependent protein controls of synchronous and asynchronous vesicle release, rapid replenishment of the active zone, endocytosis, and short-term plasticity within 100 msec after the action potential. Furthermore, I discuss the contribution of active zone proteins to presynaptic plasticity and to homeostatic readjustment during and after intense activity, in addition to activity-dependent endocytosis.
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Affiliation(s)
- Sumiko Mochida
- Department of Physiology, Tokyo Medical University, Tokyo 160-8402, Japan
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8
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Zarcone TJ. Neuroscience and Actometry: an example of the benefits of the precise measurement of behavior. Brain Res Bull 2022; 185:86-90. [PMID: 35472566 DOI: 10.1016/j.brainresbull.2022.04.009] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2021] [Revised: 04/19/2022] [Accepted: 04/20/2022] [Indexed: 12/20/2022]
Abstract
PURPOSE Assess the impact the force-plate actometer, invented by Stephen C. Fowler, has had on behavioral neuroscience so far and what may be possible for future progress. METHODS The web service Scopus was queried on April 28, 2021 for articles that cited the Journal of Neuroscience Methods paper titled "A force-plate actometer for quantitating rodent behaviors: illustrative data on locomotion, rotation, spatial patterning, stereotypies, and tremor" resulting in 134 articles. Articles were coded by the author for type (e.g., research, review, book chapter), phenomenon (e.g., stress, addiction), intervention (e.g., pharmacological), and measure (e.g., distance traveled, tremor). CONCLUSIONS Of the 134 citations, 116 were research articles, 10 were review articles, 7 were book chapters and one was an advertisement. The force-plate actometer has been used to study a variety of phenomena and its measurement capabilities were expanded. While primarily used for rats and mice, other species have been used.
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Affiliation(s)
- Troy J Zarcone
- National Institute on Drug Abuse, 301 North Stonestreet Ave, Bethesda, MD 20892.
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9
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Glutamatergic synapses from the insular cortex to the basolateral amygdala encode observational pain. Neuron 2022; 110:1993-2008.e6. [PMID: 35443154 DOI: 10.1016/j.neuron.2022.03.030] [Citation(s) in RCA: 45] [Impact Index Per Article: 22.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2021] [Revised: 01/30/2022] [Accepted: 03/23/2022] [Indexed: 02/06/2023]
Abstract
Empathic pain has attracted the interest of a substantial number of researchers studying the social transfer of pain in the sociological, psychological, and neuroscience fields. However, the neural mechanism of empathic pain remains elusive. Here, we establish a long-term observational pain model in mice and find that glutamatergic projection from the insular cortex (IC) to the basolateral amygdala (BLA) is critical for the formation of observational pain. The selective activation or inhibition of the IC-BLA projection pathway strengthens or weakens the intensity of observational pain, respectively. The synaptic molecules are screened, and the upregulated synaptotagmin-2 and RIM3 are identified as key signals in controlling the increased synaptic glutamate transmission from the IC to the BLA. Together, these results reveal the molecular and synaptic mechanisms of a previously unidentified neural pathway that regulates observational pain in mice.
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10
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Peters JJ, Leitz J, Oses-Prieto JA, Burlingame AL, Brunger AT. Molecular Characterization of AMPA-Receptor-Containing Vesicles. Front Mol Neurosci 2021; 14:754631. [PMID: 34720876 PMCID: PMC8554035 DOI: 10.3389/fnmol.2021.754631] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2021] [Accepted: 09/16/2021] [Indexed: 12/13/2022] Open
Abstract
Regulated delivery of AMPA receptors (AMPARs) to the postsynaptic membrane is an essential step in synaptic strength modification, and in particular, long-term potentiation (LTP). While LTP has been extensively studied using electrophysiology and light microscopy, several questions regarding the molecular mechanisms of AMPAR delivery via trafficking vesicles remain outstanding, including the gross molecular make up of AMPAR trafficking organelles and identification and location of calcium sensors required for SNARE complex-dependent membrane fusion of such trafficking vesicles with the plasma membrane. Here, we isolated AMPA-containing vesicles (ACVs) from whole mouse brains via immunoisolation and characterized them using immunoelectron microscopy, immunoblotting, and liquid chromatography–tandem mass spectrometry (LC–MS/MS). We identified several proteins on ACVs that were previously found to play a role in AMPAR trafficking, including synaptobrevin-2, Rabs, the SM protein Munc18-1, the calcium-sensor synaptotagmin-1, as well as several new candidates, including synaptophysin and synaptogyrin on ACV membranes. Additionally, we identified two populations of ACVs based on size and molecular composition: small-diameter, synaptobrevin-2- and GluA1-containing ACVs, and larger transferrin- receptor-, GluA1-, GluA2-, and GluA3-containing ACVs. The small-diameter population of ACVs may represent a fusion-capable population of vesicles due to the presence of synaptobrevin-2. Because the fusion of ACVs may be a requisite of LTP, this population could represent trafficking vesicles related to LTP.
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Affiliation(s)
- John Jacob Peters
- Department of Molecular and Cellular Physiology, Stanford University, Stanford, CA, United States.,Department of Neurology and Neurological Sciences, Stanford University, Stanford, CA, United States.,Department of Structural Biology, Stanford University, Stanford, CA, United States.,Department of Photon Science, Stanford University, Stanford, CA, United States.,Howard Hughes Medical Institute, Stanford University, Stanford, CA, United States
| | - Jeremy Leitz
- Department of Molecular and Cellular Physiology, Stanford University, Stanford, CA, United States.,Department of Neurology and Neurological Sciences, Stanford University, Stanford, CA, United States.,Department of Structural Biology, Stanford University, Stanford, CA, United States.,Department of Photon Science, Stanford University, Stanford, CA, United States.,Howard Hughes Medical Institute, Stanford University, Stanford, CA, United States
| | - Juan A Oses-Prieto
- Department of Pharmaceutical Chemistry, University of California, San Francisco, San Francisco, CA, United States
| | - Alma L Burlingame
- Department of Pharmaceutical Chemistry, University of California, San Francisco, San Francisco, CA, United States
| | - Axel T Brunger
- Department of Molecular and Cellular Physiology, Stanford University, Stanford, CA, United States.,Department of Neurology and Neurological Sciences, Stanford University, Stanford, CA, United States.,Department of Structural Biology, Stanford University, Stanford, CA, United States.,Department of Photon Science, Stanford University, Stanford, CA, United States.,Howard Hughes Medical Institute, Stanford University, Stanford, CA, United States
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11
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Li WR, Wang YL, Li C, Gao P, Zhang FF, Hu M, Li JC, Zhang S, Li R, Zhang CX. Synaptotagmin-11 inhibits spontaneous neurotransmission through vti1a. J Neurochem 2021; 159:729-741. [PMID: 34599505 DOI: 10.1111/jnc.15523] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2019] [Revised: 11/25/2020] [Accepted: 09/26/2021] [Indexed: 12/25/2022]
Abstract
Recent work has revealed that spontaneous release plays critical roles in the central nervous system, but how it is regulated remains elusive. Here, we report that synaptotagmin-11 (Syt11), a Ca2+ -independent Syt isoform associated with schizophrenia and Parkinson's disease, suppressed spontaneous release. Syt11-knockout hippocampal neurons showed an increased frequency of miniature excitatory post-synaptic currents while over-expression of Syt11 inversely decreased the frequency. Neither knockout nor over-expression of Syt11 affected the average amplitude, suggesting the pre-synaptic regulation of spontaneous neurotransmission by Syt11. Glutathione S-transferase pull-down, co-immunoprecipitation, and affinity-purification experiments demonstrated a direct interaction of Syt11 with vps10p-tail-interactor-1a (vti1a), a non-canonical SNARE protein that maintains spontaneous release. Importantly, knockdown of vti1a reversed the phenotype of Syt11 knockout, identifying vti1a as the main target of Syt11 inhibition. Domain analysis revealed that the C2A domain of Syt11 bound vti1a with high affinity. Consistently, expression of the C2A domain alone rescued the phenotype of elevated spontaneous release in Syt11-knockout neurons similar to the full-length protein. Altogether, our results suggest that Syt11 inhibits vti1a-containing vesicles during spontaneous release.
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Affiliation(s)
- Wan-Ru Li
- Beijing Institute of Brain Disorders, Laboratory of Brain Disorders, Ministry of Science and Technology, Collaborative Innovation Center for Brain Disorders, Capital Medical University, Beijing, China
| | - Ya-Long Wang
- Beijing Institute of Brain Disorders, Laboratory of Brain Disorders, Ministry of Science and Technology, Collaborative Innovation Center for Brain Disorders, Capital Medical University, Beijing, China
| | - Chao Li
- State Key Laboratory of Brain and Cognitive Sciences, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China.,University of Chinese Academy of Sciences, Beijing, China
| | - Pei Gao
- Beijing Institute of Brain Disorders, Laboratory of Brain Disorders, Ministry of Science and Technology, Collaborative Innovation Center for Brain Disorders, Capital Medical University, Beijing, China
| | - Fei-Fan Zhang
- Beijing Institute of Brain Disorders, Laboratory of Brain Disorders, Ministry of Science and Technology, Collaborative Innovation Center for Brain Disorders, Capital Medical University, Beijing, China
| | - Meiqin Hu
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, Michigan, USA
| | - Jing-Chen Li
- Beijing Institute of Brain Disorders, Laboratory of Brain Disorders, Ministry of Science and Technology, Collaborative Innovation Center for Brain Disorders, Capital Medical University, Beijing, China
| | - Shuli Zhang
- State Key Laboratory of Brain and Cognitive Sciences, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China.,University of Chinese Academy of Sciences, Beijing, China
| | - Rena Li
- Beijing Key Laboratory of Mental Disorders, Beijing Anding Hospital and Beijing Institute of Brain Disorders, Capital Medical University, Beijing, China
| | - Claire Xi Zhang
- Beijing Institute of Brain Disorders, Laboratory of Brain Disorders, Ministry of Science and Technology, Collaborative Innovation Center for Brain Disorders, Capital Medical University, Beijing, China.,Academy of Pharmacy, Xi'an Jiaotong-Liverpool University, Suzhou, China
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12
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Li L, Liu H, Krout M, Richmond JE, Wang Y, Bai J, Weeratunga S, Collins BM, Ventimiglia D, Yu Y, Xia J, Tang J, Liu J, Hu Z. A novel dual Ca2+ sensor system regulates Ca2+-dependent neurotransmitter release. J Cell Biol 2021; 220:211787. [PMID: 33570571 PMCID: PMC7883739 DOI: 10.1083/jcb.202008121] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2020] [Revised: 12/19/2020] [Accepted: 01/15/2021] [Indexed: 02/08/2023] Open
Abstract
Ca2+-dependent neurotransmitter release requires synaptotagmins as Ca2+ sensors to trigger synaptic vesicle (SV) exocytosis via binding of their tandem C2 domains—C2A and C2B—to Ca2+. We have previously demonstrated that SNT-1, a mouse synaptotagmin-1 (Syt1) homologue, functions as the fast Ca2+ sensor in Caenorhabditis elegans. Here, we report a new Ca2+ sensor, SNT-3, which triggers delayed Ca2+-dependent neurotransmitter release. snt-1;snt-3 double mutants abolish evoked synaptic transmission, demonstrating that C. elegans NMJs use a dual Ca2+ sensor system. SNT-3 possesses canonical aspartate residues in both C2 domains, but lacks an N-terminal transmembrane (TM) domain. Biochemical evidence demonstrates that SNT-3 binds both Ca2+ and the plasma membrane. Functional analysis shows that SNT-3 is activated when SNT-1 function is impaired, triggering SV release that is loosely coupled to Ca2+ entry. Compared with SNT-1, which is tethered to SVs, SNT-3 is not associated with SV. Eliminating the SV tethering of SNT-1 by removing the TM domain or the whole N terminus rescues fast release kinetics, demonstrating that cytoplasmic SNT-1 is still functional and triggers fast neurotransmitter release, but also exhibits decreased evoked amplitude and release probability. These results suggest that the fast and slow properties of SV release are determined by the intrinsically different C2 domains in SNT-1 and SNT-3, rather than their N-termini–mediated membrane tethering. Our findings therefore reveal a novel dual Ca2+ sensor system in C. elegans and provide significant insights into Ca2+-regulated exocytosis.
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Affiliation(s)
- Lei Li
- Queensland Brain Institute, Clem Jones Centre for Ageing Dementia Research, The University of Queensland, Brisbane, Queensland, Australia
| | - Haowen Liu
- Queensland Brain Institute, Clem Jones Centre for Ageing Dementia Research, The University of Queensland, Brisbane, Queensland, Australia
| | - Mia Krout
- Department of Biological Sciences, University of Illinois at Chicago, Chicago, IL
| | - Janet E Richmond
- Department of Biological Sciences, University of Illinois at Chicago, Chicago, IL
| | - Yu Wang
- Division of Basic Sciences, Fred Hutchinson Cancer Research Center, Seattle, WA
| | - Jihong Bai
- Division of Basic Sciences, Fred Hutchinson Cancer Research Center, Seattle, WA
| | - Saroja Weeratunga
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Queensland, Australia
| | - Brett M Collins
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Queensland, Australia
| | - Donovan Ventimiglia
- Lulu and Anthony Wang Laboratory of Neural Circuits and Behavior, The Rockefeller University, New York, NY
| | - Yi Yu
- Queensland Brain Institute, Clem Jones Centre for Ageing Dementia Research, The University of Queensland, Brisbane, Queensland, Australia
| | - Jingyao Xia
- Queensland Brain Institute, Clem Jones Centre for Ageing Dementia Research, The University of Queensland, Brisbane, Queensland, Australia
| | - Jing Tang
- Queensland Brain Institute, Clem Jones Centre for Ageing Dementia Research, The University of Queensland, Brisbane, Queensland, Australia
| | - Jie Liu
- Neuroscience Program, Monash Biomedicine Discovery Institute and Department of Anatomy and Developmental Biology, Monash University, Melbourne, Victoria, Australia
| | - Zhitao Hu
- Queensland Brain Institute, Clem Jones Centre for Ageing Dementia Research, The University of Queensland, Brisbane, Queensland, Australia
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13
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Maselli RA, Wei DT, Hodgson TS, Sampson JB, Vazquez J, Smith HL, Pytel P, Ferns M. Dominant and recessive congenital myasthenic syndromes caused by SYT2 mutations. Muscle Nerve 2021; 64:219-224. [PMID: 34037996 DOI: 10.1002/mus.27332] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2021] [Revised: 05/14/2021] [Accepted: 05/19/2021] [Indexed: 01/11/2023]
Abstract
INTRODUCTION/AIMS We studied a patient with a congenital myasthenic syndrome (CMS) caused by a dominant mutation in the synaptotagmin 2 gene (SYT2) and compared the clinical features of this patient with those of a previously described patient with a recessive mutation in the same gene. METHODS We performed electrodiagnostic (EDX) studies, genetic studies, muscle biopsy, microelectrode recordings and electron microscopy (EM). RESULTS Both patients presented with muscle weakness and bulbar deficits, which were worse in the recessive form. EDX studies showed presynaptic failure, which was more prominent in the recessive form. Microelectrode studies in the dominant form showed a marked reduction of the quantal content, which increased linearly with higher frequencies of nerve stimulation. The MEPP frequencies were normal at rest but increased markedly with higher frequencies of nerve stimulation. The EM demonstrated overdeveloped postsynaptic folding, and abundant endosomes, multivesicular bodies and degenerative lamellar bodies inside small nerve terminals. DISCUSSION The recessive form of CMS caused by a SYT2 mutation showed far more severe clinical manifestations than the dominant form. The pathogenesis of the dominant form likely involves a dominant-negative effect due to disruption of the dual function of synaptotagmin as a Ca2+ -sensor and modulator of synaptic vesicle exocytosis.
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Affiliation(s)
- Ricardo A Maselli
- Department of Neurology, University of California Davis, Sacramento, California, USA
| | - David T Wei
- Department of Neurology, University of California Davis, Sacramento, California, USA
| | - Trent S Hodgson
- Kaiser Permanente Oakland Medical Center, Oakland, California, USA
| | - Jacinda B Sampson
- Department of Neurology, Stanford University, Palo Alto, California, USA
| | - Jessica Vazquez
- Department of Neurology, University of California Davis, Sacramento, California, USA
| | - Heather L Smith
- Department of Pathology, The University of Chicago, Chicago, Illinois, USA
| | - Peter Pytel
- Department of Pathology, The University of Chicago, Chicago, Illinois, USA
| | - Michael Ferns
- Department of Anesthesiology, University of California Davis, Davis, California, USA
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14
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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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15
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Goode C, Voeun M, Ncube D, Eisen J, Washbourne P, Tallafuss A. Late onset of Synaptotagmin 2a expression at synapses relevant to social behavior. J Comp Neurol 2021; 529:2176-2188. [PMID: 33491202 DOI: 10.1002/cne.25084] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2020] [Revised: 10/30/2020] [Accepted: 11/23/2020] [Indexed: 12/15/2022]
Abstract
As they form, synapses go through various stages of maturation and refinement. These steps are linked to significant changes in synaptic function, potentially resulting in emergence and maturation of behavioral outputs. Synaptotagmins are calcium-sensing proteins of the synaptic vesicle exocytosis machinery, and changes in Synaptotagmin proteins at synapses have significant effects on vesicle release and synaptic function. Here, we examined the distribution of the synaptic vesicle protein Synaptotagmin 2a (Syt2a) during development of the zebrafish nervous system. Syt2a is widely distributed throughout the midbrain and hindbrain early during larval development but very weakly expressed in the forebrain. Later in development, Syt2a expression levels in the forebrain increase, particularly in regions associated with social behavior, and most intriguingly, around the time social behavior becomes apparent. We provide evidence that Syt2a localizes to synapses onto neurons implicated in social behavior in the ventral forebrain and show that Syt2a is colocalized with tyrosine hydroxylase, a biosynthetic enzyme in the dopamine pathway. Our results suggest a developmentally important role for Syt2a in maturing synapses in the forebrain, coinciding with the emergence of social behavior.
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Affiliation(s)
- Collette Goode
- Institute of Neuroscience, University of Oregon, Eugene, USA
| | - Mae Voeun
- Institute of Neuroscience, University of Oregon, Eugene, USA
| | - Denver Ncube
- Institute of Neuroscience, University of Oregon, Eugene, USA
| | - Judith Eisen
- Institute of Neuroscience, University of Oregon, Eugene, USA
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16
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Bauché S, Sureau A, Sternberg D, Rendu J, Buon C, Messéant J, Boëx M, Furling D, Fauré J, Latypova X, Gelot AB, Mayer M, Mary P, Whalen S, Fournier E, Cloix I, Remerand G, Laffargue F, Nougues MC, Fontaine B, Eymard B, Isapof A, Strochlic L. New recessive mutations in SYT2 causing severe presynaptic congenital myasthenic syndromes. NEUROLOGY-GENETICS 2020; 6:e534. [PMID: 33659639 PMCID: PMC7803339 DOI: 10.1212/nxg.0000000000000534] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/18/2020] [Accepted: 09/25/2020] [Indexed: 11/15/2022]
Abstract
Objective To report the identification of 2 new homozygous recessive mutations in the synaptotagmin 2 (SYT2) gene as the genetic cause of severe and early presynaptic forms of congenital myasthenic syndromes (CMSs). Methods Next-generation sequencing identified new homozygous intronic and frameshift mutations in the SYT2 gene as a likely cause of presynaptic CMS. We describe the clinical and electromyographic patient phenotypes, perform ex vivo splicing analyses to characterize the effect of the intronic mutation on exon splicing, and analyze the functional impact of this variation at the neuromuscular junction (NMJ). Results The 2 infants presented a similar clinical phenotype evoking first a congenital myopathy characterized by muscle weakness and hypotonia. Next-generation sequencing allowed to the identification of 1 homozygous intronic mutation c.465+1G>A in patient 1 and another homozygous frameshift mutation c.328_331dup in patient 2, located respectively in the 5' splice donor site of SYT2 intron 4 and in exon 3. Functional studies of the intronic mutation validated the abolition of the splice donor site of exon 4 leading to its skipping. In-frame skipping of exon 4 that encodes part of the C2A calcium-binding domain of SYT2 is associated with a loss-of-function effect resulting in a decrease of neurotransmitter release and severe pre- and postsynaptic NMJ defects. Conclusions This study identifies new homozygous recessive SYT2 mutations as the underlying cause of severe and early presynaptic form of CMS expanding the genetic spectrum of recessive SYT2-related CMS associated with defects in neurotransmitter release.
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Affiliation(s)
- Stéphanie Bauché
- Sorbonne Université, INSERM, UMRS974, Centre de Recherche en Myologie, Hôpital de la Pitié-Salpêtrière, Paris, (S.B., A.S., C. B., J.M., M.B., D.F., E. F., B.F., B.E., A.I., L.S.); CHU APHP (D.S., J.R., J.F., X.L., A.B.G., M.M., P.M., S.W., E.F., I.C., G.R., F.L., M.C.N., B.F., B.E., A.I.); Aix-Marseille University, INSERM, INMED, Campus de Luminy, Marseille, France (A.B.G.); UFR Cardiogénétique et Myogénétique, Hôpital de la Pitié-Salpêtrière, APHP, Paris (D.S.); UF de génétique clinique, CRMR Anomalies du développement et syndromes malformatifs, APHP, Hôpital Armand Trousseau, Paris, France (S.W.); Université de Grenoble Alpes, INSERM, CHU Grenoble Alpes, GIN (J.R., J.F., X.L.); CHU Clermont Ferrand (I.C., G.R., F.L.); and Reference Centre for Neuromuscular Pathologies "Nord/Est/Ile-de France" Paris (A.B.G., M.M., P.M., S.W., M.C.N., B.F., B.E., A.I.)
| | - Alain Sureau
- Sorbonne Université, INSERM, UMRS974, Centre de Recherche en Myologie, Hôpital de la Pitié-Salpêtrière, Paris, (S.B., A.S., C. B., J.M., M.B., D.F., E. F., B.F., B.E., A.I., L.S.); CHU APHP (D.S., J.R., J.F., X.L., A.B.G., M.M., P.M., S.W., E.F., I.C., G.R., F.L., M.C.N., B.F., B.E., A.I.); Aix-Marseille University, INSERM, INMED, Campus de Luminy, Marseille, France (A.B.G.); UFR Cardiogénétique et Myogénétique, Hôpital de la Pitié-Salpêtrière, APHP, Paris (D.S.); UF de génétique clinique, CRMR Anomalies du développement et syndromes malformatifs, APHP, Hôpital Armand Trousseau, Paris, France (S.W.); Université de Grenoble Alpes, INSERM, CHU Grenoble Alpes, GIN (J.R., J.F., X.L.); CHU Clermont Ferrand (I.C., G.R., F.L.); and Reference Centre for Neuromuscular Pathologies "Nord/Est/Ile-de France" Paris (A.B.G., M.M., P.M., S.W., M.C.N., B.F., B.E., A.I.)
| | - Damien Sternberg
- Sorbonne Université, INSERM, UMRS974, Centre de Recherche en Myologie, Hôpital de la Pitié-Salpêtrière, Paris, (S.B., A.S., C. B., J.M., M.B., D.F., E. F., B.F., B.E., A.I., L.S.); CHU APHP (D.S., J.R., J.F., X.L., A.B.G., M.M., P.M., S.W., E.F., I.C., G.R., F.L., M.C.N., B.F., B.E., A.I.); Aix-Marseille University, INSERM, INMED, Campus de Luminy, Marseille, France (A.B.G.); UFR Cardiogénétique et Myogénétique, Hôpital de la Pitié-Salpêtrière, APHP, Paris (D.S.); UF de génétique clinique, CRMR Anomalies du développement et syndromes malformatifs, APHP, Hôpital Armand Trousseau, Paris, France (S.W.); Université de Grenoble Alpes, INSERM, CHU Grenoble Alpes, GIN (J.R., J.F., X.L.); CHU Clermont Ferrand (I.C., G.R., F.L.); and Reference Centre for Neuromuscular Pathologies "Nord/Est/Ile-de France" Paris (A.B.G., M.M., P.M., S.W., M.C.N., B.F., B.E., A.I.)
| | - John Rendu
- Sorbonne Université, INSERM, UMRS974, Centre de Recherche en Myologie, Hôpital de la Pitié-Salpêtrière, Paris, (S.B., A.S., C. B., J.M., M.B., D.F., E. F., B.F., B.E., A.I., L.S.); CHU APHP (D.S., J.R., J.F., X.L., A.B.G., M.M., P.M., S.W., E.F., I.C., G.R., F.L., M.C.N., B.F., B.E., A.I.); Aix-Marseille University, INSERM, INMED, Campus de Luminy, Marseille, France (A.B.G.); UFR Cardiogénétique et Myogénétique, Hôpital de la Pitié-Salpêtrière, APHP, Paris (D.S.); UF de génétique clinique, CRMR Anomalies du développement et syndromes malformatifs, APHP, Hôpital Armand Trousseau, Paris, France (S.W.); Université de Grenoble Alpes, INSERM, CHU Grenoble Alpes, GIN (J.R., J.F., X.L.); CHU Clermont Ferrand (I.C., G.R., F.L.); and Reference Centre for Neuromuscular Pathologies "Nord/Est/Ile-de France" Paris (A.B.G., M.M., P.M., S.W., M.C.N., B.F., B.E., A.I.)
| | - Céline Buon
- Sorbonne Université, INSERM, UMRS974, Centre de Recherche en Myologie, Hôpital de la Pitié-Salpêtrière, Paris, (S.B., A.S., C. B., J.M., M.B., D.F., E. F., B.F., B.E., A.I., L.S.); CHU APHP (D.S., J.R., J.F., X.L., A.B.G., M.M., P.M., S.W., E.F., I.C., G.R., F.L., M.C.N., B.F., B.E., A.I.); Aix-Marseille University, INSERM, INMED, Campus de Luminy, Marseille, France (A.B.G.); UFR Cardiogénétique et Myogénétique, Hôpital de la Pitié-Salpêtrière, APHP, Paris (D.S.); UF de génétique clinique, CRMR Anomalies du développement et syndromes malformatifs, APHP, Hôpital Armand Trousseau, Paris, France (S.W.); Université de Grenoble Alpes, INSERM, CHU Grenoble Alpes, GIN (J.R., J.F., X.L.); CHU Clermont Ferrand (I.C., G.R., F.L.); and Reference Centre for Neuromuscular Pathologies "Nord/Est/Ile-de France" Paris (A.B.G., M.M., P.M., S.W., M.C.N., B.F., B.E., A.I.)
| | - Julien Messéant
- Sorbonne Université, INSERM, UMRS974, Centre de Recherche en Myologie, Hôpital de la Pitié-Salpêtrière, Paris, (S.B., A.S., C. B., J.M., M.B., D.F., E. F., B.F., B.E., A.I., L.S.); CHU APHP (D.S., J.R., J.F., X.L., A.B.G., M.M., P.M., S.W., E.F., I.C., G.R., F.L., M.C.N., B.F., B.E., A.I.); Aix-Marseille University, INSERM, INMED, Campus de Luminy, Marseille, France (A.B.G.); UFR Cardiogénétique et Myogénétique, Hôpital de la Pitié-Salpêtrière, APHP, Paris (D.S.); UF de génétique clinique, CRMR Anomalies du développement et syndromes malformatifs, APHP, Hôpital Armand Trousseau, Paris, France (S.W.); Université de Grenoble Alpes, INSERM, CHU Grenoble Alpes, GIN (J.R., J.F., X.L.); CHU Clermont Ferrand (I.C., G.R., F.L.); and Reference Centre for Neuromuscular Pathologies "Nord/Est/Ile-de France" Paris (A.B.G., M.M., P.M., S.W., M.C.N., B.F., B.E., A.I.)
| | - Myriam Boëx
- Sorbonne Université, INSERM, UMRS974, Centre de Recherche en Myologie, Hôpital de la Pitié-Salpêtrière, Paris, (S.B., A.S., C. B., J.M., M.B., D.F., E. F., B.F., B.E., A.I., L.S.); CHU APHP (D.S., J.R., J.F., X.L., A.B.G., M.M., P.M., S.W., E.F., I.C., G.R., F.L., M.C.N., B.F., B.E., A.I.); Aix-Marseille University, INSERM, INMED, Campus de Luminy, Marseille, France (A.B.G.); UFR Cardiogénétique et Myogénétique, Hôpital de la Pitié-Salpêtrière, APHP, Paris (D.S.); UF de génétique clinique, CRMR Anomalies du développement et syndromes malformatifs, APHP, Hôpital Armand Trousseau, Paris, France (S.W.); Université de Grenoble Alpes, INSERM, CHU Grenoble Alpes, GIN (J.R., J.F., X.L.); CHU Clermont Ferrand (I.C., G.R., F.L.); and Reference Centre for Neuromuscular Pathologies "Nord/Est/Ile-de France" Paris (A.B.G., M.M., P.M., S.W., M.C.N., B.F., B.E., A.I.)
| | - Denis Furling
- Sorbonne Université, INSERM, UMRS974, Centre de Recherche en Myologie, Hôpital de la Pitié-Salpêtrière, Paris, (S.B., A.S., C. B., J.M., M.B., D.F., E. F., B.F., B.E., A.I., L.S.); CHU APHP (D.S., J.R., J.F., X.L., A.B.G., M.M., P.M., S.W., E.F., I.C., G.R., F.L., M.C.N., B.F., B.E., A.I.); Aix-Marseille University, INSERM, INMED, Campus de Luminy, Marseille, France (A.B.G.); UFR Cardiogénétique et Myogénétique, Hôpital de la Pitié-Salpêtrière, APHP, Paris (D.S.); UF de génétique clinique, CRMR Anomalies du développement et syndromes malformatifs, APHP, Hôpital Armand Trousseau, Paris, France (S.W.); Université de Grenoble Alpes, INSERM, CHU Grenoble Alpes, GIN (J.R., J.F., X.L.); CHU Clermont Ferrand (I.C., G.R., F.L.); and Reference Centre for Neuromuscular Pathologies "Nord/Est/Ile-de France" Paris (A.B.G., M.M., P.M., S.W., M.C.N., B.F., B.E., A.I.)
| | - Julien Fauré
- Sorbonne Université, INSERM, UMRS974, Centre de Recherche en Myologie, Hôpital de la Pitié-Salpêtrière, Paris, (S.B., A.S., C. B., J.M., M.B., D.F., E. F., B.F., B.E., A.I., L.S.); CHU APHP (D.S., J.R., J.F., X.L., A.B.G., M.M., P.M., S.W., E.F., I.C., G.R., F.L., M.C.N., B.F., B.E., A.I.); Aix-Marseille University, INSERM, INMED, Campus de Luminy, Marseille, France (A.B.G.); UFR Cardiogénétique et Myogénétique, Hôpital de la Pitié-Salpêtrière, APHP, Paris (D.S.); UF de génétique clinique, CRMR Anomalies du développement et syndromes malformatifs, APHP, Hôpital Armand Trousseau, Paris, France (S.W.); Université de Grenoble Alpes, INSERM, CHU Grenoble Alpes, GIN (J.R., J.F., X.L.); CHU Clermont Ferrand (I.C., G.R., F.L.); and Reference Centre for Neuromuscular Pathologies "Nord/Est/Ile-de France" Paris (A.B.G., M.M., P.M., S.W., M.C.N., B.F., B.E., A.I.)
| | - Xénia Latypova
- Sorbonne Université, INSERM, UMRS974, Centre de Recherche en Myologie, Hôpital de la Pitié-Salpêtrière, Paris, (S.B., A.S., C. B., J.M., M.B., D.F., E. F., B.F., B.E., A.I., L.S.); CHU APHP (D.S., J.R., J.F., X.L., A.B.G., M.M., P.M., S.W., E.F., I.C., G.R., F.L., M.C.N., B.F., B.E., A.I.); Aix-Marseille University, INSERM, INMED, Campus de Luminy, Marseille, France (A.B.G.); UFR Cardiogénétique et Myogénétique, Hôpital de la Pitié-Salpêtrière, APHP, Paris (D.S.); UF de génétique clinique, CRMR Anomalies du développement et syndromes malformatifs, APHP, Hôpital Armand Trousseau, Paris, France (S.W.); Université de Grenoble Alpes, INSERM, CHU Grenoble Alpes, GIN (J.R., J.F., X.L.); CHU Clermont Ferrand (I.C., G.R., F.L.); and Reference Centre for Neuromuscular Pathologies "Nord/Est/Ile-de France" Paris (A.B.G., M.M., P.M., S.W., M.C.N., B.F., B.E., A.I.)
| | - Antoinette Bernabe Gelot
- Sorbonne Université, INSERM, UMRS974, Centre de Recherche en Myologie, Hôpital de la Pitié-Salpêtrière, Paris, (S.B., A.S., C. B., J.M., M.B., D.F., E. F., B.F., B.E., A.I., L.S.); CHU APHP (D.S., J.R., J.F., X.L., A.B.G., M.M., P.M., S.W., E.F., I.C., G.R., F.L., M.C.N., B.F., B.E., A.I.); Aix-Marseille University, INSERM, INMED, Campus de Luminy, Marseille, France (A.B.G.); UFR Cardiogénétique et Myogénétique, Hôpital de la Pitié-Salpêtrière, APHP, Paris (D.S.); UF de génétique clinique, CRMR Anomalies du développement et syndromes malformatifs, APHP, Hôpital Armand Trousseau, Paris, France (S.W.); Université de Grenoble Alpes, INSERM, CHU Grenoble Alpes, GIN (J.R., J.F., X.L.); CHU Clermont Ferrand (I.C., G.R., F.L.); and Reference Centre for Neuromuscular Pathologies "Nord/Est/Ile-de France" Paris (A.B.G., M.M., P.M., S.W., M.C.N., B.F., B.E., A.I.)
| | - Michèle Mayer
- Sorbonne Université, INSERM, UMRS974, Centre de Recherche en Myologie, Hôpital de la Pitié-Salpêtrière, Paris, (S.B., A.S., C. B., J.M., M.B., D.F., E. F., B.F., B.E., A.I., L.S.); CHU APHP (D.S., J.R., J.F., X.L., A.B.G., M.M., P.M., S.W., E.F., I.C., G.R., F.L., M.C.N., B.F., B.E., A.I.); Aix-Marseille University, INSERM, INMED, Campus de Luminy, Marseille, France (A.B.G.); UFR Cardiogénétique et Myogénétique, Hôpital de la Pitié-Salpêtrière, APHP, Paris (D.S.); UF de génétique clinique, CRMR Anomalies du développement et syndromes malformatifs, APHP, Hôpital Armand Trousseau, Paris, France (S.W.); Université de Grenoble Alpes, INSERM, CHU Grenoble Alpes, GIN (J.R., J.F., X.L.); CHU Clermont Ferrand (I.C., G.R., F.L.); and Reference Centre for Neuromuscular Pathologies "Nord/Est/Ile-de France" Paris (A.B.G., M.M., P.M., S.W., M.C.N., B.F., B.E., A.I.)
| | - Pierre Mary
- Sorbonne Université, INSERM, UMRS974, Centre de Recherche en Myologie, Hôpital de la Pitié-Salpêtrière, Paris, (S.B., A.S., C. B., J.M., M.B., D.F., E. F., B.F., B.E., A.I., L.S.); CHU APHP (D.S., J.R., J.F., X.L., A.B.G., M.M., P.M., S.W., E.F., I.C., G.R., F.L., M.C.N., B.F., B.E., A.I.); Aix-Marseille University, INSERM, INMED, Campus de Luminy, Marseille, France (A.B.G.); UFR Cardiogénétique et Myogénétique, Hôpital de la Pitié-Salpêtrière, APHP, Paris (D.S.); UF de génétique clinique, CRMR Anomalies du développement et syndromes malformatifs, APHP, Hôpital Armand Trousseau, Paris, France (S.W.); Université de Grenoble Alpes, INSERM, CHU Grenoble Alpes, GIN (J.R., J.F., X.L.); CHU Clermont Ferrand (I.C., G.R., F.L.); and Reference Centre for Neuromuscular Pathologies "Nord/Est/Ile-de France" Paris (A.B.G., M.M., P.M., S.W., M.C.N., B.F., B.E., A.I.)
| | - Sandra Whalen
- Sorbonne Université, INSERM, UMRS974, Centre de Recherche en Myologie, Hôpital de la Pitié-Salpêtrière, Paris, (S.B., A.S., C. B., J.M., M.B., D.F., E. F., B.F., B.E., A.I., L.S.); CHU APHP (D.S., J.R., J.F., X.L., A.B.G., M.M., P.M., S.W., E.F., I.C., G.R., F.L., M.C.N., B.F., B.E., A.I.); Aix-Marseille University, INSERM, INMED, Campus de Luminy, Marseille, France (A.B.G.); UFR Cardiogénétique et Myogénétique, Hôpital de la Pitié-Salpêtrière, APHP, Paris (D.S.); UF de génétique clinique, CRMR Anomalies du développement et syndromes malformatifs, APHP, Hôpital Armand Trousseau, Paris, France (S.W.); Université de Grenoble Alpes, INSERM, CHU Grenoble Alpes, GIN (J.R., J.F., X.L.); CHU Clermont Ferrand (I.C., G.R., F.L.); and Reference Centre for Neuromuscular Pathologies "Nord/Est/Ile-de France" Paris (A.B.G., M.M., P.M., S.W., M.C.N., B.F., B.E., A.I.)
| | - Emmanuel Fournier
- Sorbonne Université, INSERM, UMRS974, Centre de Recherche en Myologie, Hôpital de la Pitié-Salpêtrière, Paris, (S.B., A.S., C. B., J.M., M.B., D.F., E. F., B.F., B.E., A.I., L.S.); CHU APHP (D.S., J.R., J.F., X.L., A.B.G., M.M., P.M., S.W., E.F., I.C., G.R., F.L., M.C.N., B.F., B.E., A.I.); Aix-Marseille University, INSERM, INMED, Campus de Luminy, Marseille, France (A.B.G.); UFR Cardiogénétique et Myogénétique, Hôpital de la Pitié-Salpêtrière, APHP, Paris (D.S.); UF de génétique clinique, CRMR Anomalies du développement et syndromes malformatifs, APHP, Hôpital Armand Trousseau, Paris, France (S.W.); Université de Grenoble Alpes, INSERM, CHU Grenoble Alpes, GIN (J.R., J.F., X.L.); CHU Clermont Ferrand (I.C., G.R., F.L.); and Reference Centre for Neuromuscular Pathologies "Nord/Est/Ile-de France" Paris (A.B.G., M.M., P.M., S.W., M.C.N., B.F., B.E., A.I.)
| | - Isabelle Cloix
- Sorbonne Université, INSERM, UMRS974, Centre de Recherche en Myologie, Hôpital de la Pitié-Salpêtrière, Paris, (S.B., A.S., C. B., J.M., M.B., D.F., E. F., B.F., B.E., A.I., L.S.); CHU APHP (D.S., J.R., J.F., X.L., A.B.G., M.M., P.M., S.W., E.F., I.C., G.R., F.L., M.C.N., B.F., B.E., A.I.); Aix-Marseille University, INSERM, INMED, Campus de Luminy, Marseille, France (A.B.G.); UFR Cardiogénétique et Myogénétique, Hôpital de la Pitié-Salpêtrière, APHP, Paris (D.S.); UF de génétique clinique, CRMR Anomalies du développement et syndromes malformatifs, APHP, Hôpital Armand Trousseau, Paris, France (S.W.); Université de Grenoble Alpes, INSERM, CHU Grenoble Alpes, GIN (J.R., J.F., X.L.); CHU Clermont Ferrand (I.C., G.R., F.L.); and Reference Centre for Neuromuscular Pathologies "Nord/Est/Ile-de France" Paris (A.B.G., M.M., P.M., S.W., M.C.N., B.F., B.E., A.I.)
| | - Ganaelle Remerand
- Sorbonne Université, INSERM, UMRS974, Centre de Recherche en Myologie, Hôpital de la Pitié-Salpêtrière, Paris, (S.B., A.S., C. B., J.M., M.B., D.F., E. F., B.F., B.E., A.I., L.S.); CHU APHP (D.S., J.R., J.F., X.L., A.B.G., M.M., P.M., S.W., E.F., I.C., G.R., F.L., M.C.N., B.F., B.E., A.I.); Aix-Marseille University, INSERM, INMED, Campus de Luminy, Marseille, France (A.B.G.); UFR Cardiogénétique et Myogénétique, Hôpital de la Pitié-Salpêtrière, APHP, Paris (D.S.); UF de génétique clinique, CRMR Anomalies du développement et syndromes malformatifs, APHP, Hôpital Armand Trousseau, Paris, France (S.W.); Université de Grenoble Alpes, INSERM, CHU Grenoble Alpes, GIN (J.R., J.F., X.L.); CHU Clermont Ferrand (I.C., G.R., F.L.); and Reference Centre for Neuromuscular Pathologies "Nord/Est/Ile-de France" Paris (A.B.G., M.M., P.M., S.W., M.C.N., B.F., B.E., A.I.)
| | - Fanny Laffargue
- Sorbonne Université, INSERM, UMRS974, Centre de Recherche en Myologie, Hôpital de la Pitié-Salpêtrière, Paris, (S.B., A.S., C. B., J.M., M.B., D.F., E. F., B.F., B.E., A.I., L.S.); CHU APHP (D.S., J.R., J.F., X.L., A.B.G., M.M., P.M., S.W., E.F., I.C., G.R., F.L., M.C.N., B.F., B.E., A.I.); Aix-Marseille University, INSERM, INMED, Campus de Luminy, Marseille, France (A.B.G.); UFR Cardiogénétique et Myogénétique, Hôpital de la Pitié-Salpêtrière, APHP, Paris (D.S.); UF de génétique clinique, CRMR Anomalies du développement et syndromes malformatifs, APHP, Hôpital Armand Trousseau, Paris, France (S.W.); Université de Grenoble Alpes, INSERM, CHU Grenoble Alpes, GIN (J.R., J.F., X.L.); CHU Clermont Ferrand (I.C., G.R., F.L.); and Reference Centre for Neuromuscular Pathologies "Nord/Est/Ile-de France" Paris (A.B.G., M.M., P.M., S.W., M.C.N., B.F., B.E., A.I.)
| | - Marie-Christine Nougues
- Sorbonne Université, INSERM, UMRS974, Centre de Recherche en Myologie, Hôpital de la Pitié-Salpêtrière, Paris, (S.B., A.S., C. B., J.M., M.B., D.F., E. F., B.F., B.E., A.I., L.S.); CHU APHP (D.S., J.R., J.F., X.L., A.B.G., M.M., P.M., S.W., E.F., I.C., G.R., F.L., M.C.N., B.F., B.E., A.I.); Aix-Marseille University, INSERM, INMED, Campus de Luminy, Marseille, France (A.B.G.); UFR Cardiogénétique et Myogénétique, Hôpital de la Pitié-Salpêtrière, APHP, Paris (D.S.); UF de génétique clinique, CRMR Anomalies du développement et syndromes malformatifs, APHP, Hôpital Armand Trousseau, Paris, France (S.W.); Université de Grenoble Alpes, INSERM, CHU Grenoble Alpes, GIN (J.R., J.F., X.L.); CHU Clermont Ferrand (I.C., G.R., F.L.); and Reference Centre for Neuromuscular Pathologies "Nord/Est/Ile-de France" Paris (A.B.G., M.M., P.M., S.W., M.C.N., B.F., B.E., A.I.)
| | - Bertrand Fontaine
- Sorbonne Université, INSERM, UMRS974, Centre de Recherche en Myologie, Hôpital de la Pitié-Salpêtrière, Paris, (S.B., A.S., C. B., J.M., M.B., D.F., E. F., B.F., B.E., A.I., L.S.); CHU APHP (D.S., J.R., J.F., X.L., A.B.G., M.M., P.M., S.W., E.F., I.C., G.R., F.L., M.C.N., B.F., B.E., A.I.); Aix-Marseille University, INSERM, INMED, Campus de Luminy, Marseille, France (A.B.G.); UFR Cardiogénétique et Myogénétique, Hôpital de la Pitié-Salpêtrière, APHP, Paris (D.S.); UF de génétique clinique, CRMR Anomalies du développement et syndromes malformatifs, APHP, Hôpital Armand Trousseau, Paris, France (S.W.); Université de Grenoble Alpes, INSERM, CHU Grenoble Alpes, GIN (J.R., J.F., X.L.); CHU Clermont Ferrand (I.C., G.R., F.L.); and Reference Centre for Neuromuscular Pathologies "Nord/Est/Ile-de France" Paris (A.B.G., M.M., P.M., S.W., M.C.N., B.F., B.E., A.I.)
| | - Bruno Eymard
- Sorbonne Université, INSERM, UMRS974, Centre de Recherche en Myologie, Hôpital de la Pitié-Salpêtrière, Paris, (S.B., A.S., C. B., J.M., M.B., D.F., E. F., B.F., B.E., A.I., L.S.); CHU APHP (D.S., J.R., J.F., X.L., A.B.G., M.M., P.M., S.W., E.F., I.C., G.R., F.L., M.C.N., B.F., B.E., A.I.); Aix-Marseille University, INSERM, INMED, Campus de Luminy, Marseille, France (A.B.G.); UFR Cardiogénétique et Myogénétique, Hôpital de la Pitié-Salpêtrière, APHP, Paris (D.S.); UF de génétique clinique, CRMR Anomalies du développement et syndromes malformatifs, APHP, Hôpital Armand Trousseau, Paris, France (S.W.); Université de Grenoble Alpes, INSERM, CHU Grenoble Alpes, GIN (J.R., J.F., X.L.); CHU Clermont Ferrand (I.C., G.R., F.L.); and Reference Centre for Neuromuscular Pathologies "Nord/Est/Ile-de France" Paris (A.B.G., M.M., P.M., S.W., M.C.N., B.F., B.E., A.I.)
| | - Arnaud Isapof
- Sorbonne Université, INSERM, UMRS974, Centre de Recherche en Myologie, Hôpital de la Pitié-Salpêtrière, Paris, (S.B., A.S., C. B., J.M., M.B., D.F., E. F., B.F., B.E., A.I., L.S.); CHU APHP (D.S., J.R., J.F., X.L., A.B.G., M.M., P.M., S.W., E.F., I.C., G.R., F.L., M.C.N., B.F., B.E., A.I.); Aix-Marseille University, INSERM, INMED, Campus de Luminy, Marseille, France (A.B.G.); UFR Cardiogénétique et Myogénétique, Hôpital de la Pitié-Salpêtrière, APHP, Paris (D.S.); UF de génétique clinique, CRMR Anomalies du développement et syndromes malformatifs, APHP, Hôpital Armand Trousseau, Paris, France (S.W.); Université de Grenoble Alpes, INSERM, CHU Grenoble Alpes, GIN (J.R., J.F., X.L.); CHU Clermont Ferrand (I.C., G.R., F.L.); and Reference Centre for Neuromuscular Pathologies "Nord/Est/Ile-de France" Paris (A.B.G., M.M., P.M., S.W., M.C.N., B.F., B.E., A.I.)
| | - Laure Strochlic
- Sorbonne Université, INSERM, UMRS974, Centre de Recherche en Myologie, Hôpital de la Pitié-Salpêtrière, Paris, (S.B., A.S., C. B., J.M., M.B., D.F., E. F., B.F., B.E., A.I., L.S.); CHU APHP (D.S., J.R., J.F., X.L., A.B.G., M.M., P.M., S.W., E.F., I.C., G.R., F.L., M.C.N., B.F., B.E., A.I.); Aix-Marseille University, INSERM, INMED, Campus de Luminy, Marseille, France (A.B.G.); UFR Cardiogénétique et Myogénétique, Hôpital de la Pitié-Salpêtrière, APHP, Paris (D.S.); UF de génétique clinique, CRMR Anomalies du développement et syndromes malformatifs, APHP, Hôpital Armand Trousseau, Paris, France (S.W.); Université de Grenoble Alpes, INSERM, CHU Grenoble Alpes, GIN (J.R., J.F., X.L.); CHU Clermont Ferrand (I.C., G.R., F.L.); and Reference Centre for Neuromuscular Pathologies "Nord/Est/Ile-de France" Paris (A.B.G., M.M., P.M., S.W., M.C.N., B.F., B.E., A.I.)
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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: 39] [Impact Index Per Article: 9.8] [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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18
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Umbaugh DS, Jaeschke H. Extracellular vesicles: Roles and applications in drug-induced liver injury. Adv Clin Chem 2020; 102:63-125. [PMID: 34044913 DOI: 10.1016/bs.acc.2020.08.010] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Extracellular vesicles (EV) are defined as nanosized particles, with a lipid bilayer, that are unable to replicate. There has been an exponential increase of research investigating these particles in a wide array of diseases and deleterious states (inflammation, oxidative stress, drug-induced liver injury) in large part due to increasing recognition of the functional capacity of EVs. Cells can package lipids, proteins, miRNAs, DNA, and RNA into EVs and send these discrete packages of molecular information to distant, recipient cells to alter the physiological state of that cell. EVs are innately heterogeneous as a result of the diverse molecular pathways that are used to generate them. However, this innate heterogeneity of EVs is amplified due to the diversity in isolation techniques and lack of standardized nomenclature in the literature making it unclear if one scientist's "exosome" is another scientist's "microvesicle." One goal of this chapter is to provide the contextual understanding of EV origin so one can discern between divergent nomenclature. Further, the chapter will explore the potential protective and harmful roles that EVs play in DILI, and the potential of EVs and their cargo as a biomarker. The use of EVs as a therapeutic as well as a vector for therapeutic delivery will be discussed.
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Affiliation(s)
- David S Umbaugh
- Department of Pharmacology, Toxicology & Therapeutics, University of Kansas Medical Center, Kansas City, KS, United States
| | - Hartmut Jaeschke
- Department of Pharmacology, Toxicology & Therapeutics, University of Kansas Medical Center, Kansas City, KS, United States.
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19
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Ruiter M, Kádková A, Scheutzow A, Malsam J, Söllner TH, Sørensen JB. An Electrostatic Energy Barrier for SNARE-Dependent Spontaneous and Evoked Synaptic Transmission. Cell Rep 2020; 26:2340-2352.e5. [PMID: 30811985 DOI: 10.1016/j.celrep.2019.01.103] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2018] [Revised: 11/05/2018] [Accepted: 01/28/2019] [Indexed: 12/22/2022] Open
Abstract
Information transfer across CNS synapses depends on the very low basal vesicle fusion rate and the ability to rapidly upregulate that rate upon Ca2+ influx. We show that local electrostatic repulsion participates in creating an energy barrier, which limits spontaneous synaptic transmission. The barrier amplitude is increased by negative charges and decreased by positive charges on the SNARE-complex surface. Strikingly, the effect of charges on the barrier is additive and this extends to evoked transmission, but with a shallower charge dependence. Action potential-driven synaptic release is equivalent to the abrupt addition of ∼35 positive charges to the fusion machine. Within an electrostatic model for triggering, the Ca2+ sensor synaptotagmin-1 contributes ∼18 charges by binding Ca2+, while also modulating the fusion barrier at rest. Thus, the energy barrier for synaptic vesicle fusion has a large electrostatic component, allowing synaptotagmin-1 to act as an electrostatic switch and modulator to trigger vesicle fusion.
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Affiliation(s)
- Marvin Ruiter
- Department of Neuroscience, Faculty of Health and Medical Sciences, 2200 Copenhagen N, University of Copenhagen, Copenhagen, Denmark
| | - Anna Kádková
- Department of Neuroscience, Faculty of Health and Medical Sciences, 2200 Copenhagen N, University of Copenhagen, Copenhagen, Denmark
| | - Andrea Scheutzow
- Heidelberg University Biochemistry Center, 69120 Heidelberg, Germany
| | - Jörg Malsam
- Heidelberg University Biochemistry Center, 69120 Heidelberg, Germany
| | - Thomas H Söllner
- Heidelberg University Biochemistry Center, 69120 Heidelberg, Germany
| | - Jakob B Sørensen
- Department of Neuroscience, Faculty of Health and Medical Sciences, 2200 Copenhagen N, University of Copenhagen, Copenhagen, Denmark.
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20
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Huson V, Regehr WG. Diverse roles of Synaptotagmin-7 in regulating vesicle fusion. Curr Opin Neurobiol 2020; 63:42-52. [PMID: 32278209 DOI: 10.1016/j.conb.2020.02.006] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2019] [Revised: 02/12/2020] [Accepted: 02/13/2020] [Indexed: 11/18/2022]
Abstract
Synaptotagmin 7 (Syt7) is a multifunctional calcium sensor expressed throughout the body. Its high calcium affinity makes it well suited to act in processes triggered by modest calcium increases within cells. In synaptic transmission, Syt7 has been shown to mediate asynchronous neurotransmitter release, facilitation, and vesicle replenishment. In this review we provide an update on recent developments, and the newly emerging roles of Syt7 in frequency invariant synaptic transmission and in suppressing spontaneous release. Additionally, we discuss Syt7's regulation of membrane fusion in non-neuronal cells, and its involvement in disease. How such diversity of functions is regulated remains an open question. We discuss several potential factors including temperature, presynaptic calcium signals, the localization of Syt7, and its interaction with other Syt isoforms.
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21
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Ge D, Noakes PG, Lavidis NA. What are Neurotransmitter Release Sites and Do They Interact? Neuroscience 2020; 425:157-168. [DOI: 10.1016/j.neuroscience.2019.11.017] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2019] [Revised: 11/10/2019] [Accepted: 11/11/2019] [Indexed: 12/22/2022]
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Doc2b Ca 2+ binding site mutants enhance synaptic release at rest at the expense of sustained synaptic strength. Sci Rep 2019; 9:14408. [PMID: 31594980 PMCID: PMC6783474 DOI: 10.1038/s41598-019-50684-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2019] [Accepted: 09/11/2019] [Indexed: 12/01/2022] Open
Abstract
Communication between neurons involves presynaptic neurotransmitter release which can be evoked by action potentials or occur spontaneously as a result of stochastic vesicle fusion. The Ca2+-binding double C2 proteins Doc2a and –b were implicated in spontaneous and asynchronous evoked release, but the mechanism remains unclear. Here, we compared wildtype Doc2b with two Ca2+ binding site mutants named DN and 6A, previously classified as gain- and loss-of-function mutants. They carry the substitutions D218,220N or D163,218,220,303,357,359A respectively. We found that both mutants bound phospholipids at low Ca2+ concentrations and were membrane-associated in resting neurons, thus mimicking a Ca2+-activated state. Their overexpression in hippocampal primary cultured neurons had similar effects on spontaneous and evoked release, inducing high mEPSC frequencies and increased short-term depression. Together, these data suggest that the DN and 6A mutants both act as gain-of-function mutants at resting conditions.
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Spontaneous Vesicle Fusion Is Differentially Regulated at Cholinergic and GABAergic Synapses. Cell Rep 2019; 22:2334-2345. [PMID: 29490270 DOI: 10.1016/j.celrep.2018.02.023] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2017] [Revised: 01/11/2018] [Accepted: 02/06/2018] [Indexed: 12/23/2022] Open
Abstract
The locomotion of C. elegans is balanced by excitatory and inhibitory neurotransmitter release at neuromuscular junctions. However, the molecular mechanisms that maintain the balance of synaptic transmission remain enigmatic. Here, we investigated the function of voltage-gated Ca2+ channels in triggering spontaneous release at cholinergic and GABAergic synapses. Recordings of the miniature excitatory/inhibitory postsynaptic currents (mEPSCs and mIPSCs, respectively) showed that UNC-2/CaV2 and EGL-19/CaV1 channels are the two major triggers for spontaneous release. Notably, however, Ca2+-independent spontaneous release was observed at GABAergic but not cholinergic synapses. Functional screening led to the identification of hypomorphic unc-64/Syntaxin-1A and snb-1/VAMP2 mutants in which mEPSCs are severely impaired, whereas mIPSCs remain unaltered, indicating differential regulation of these currents at cholinergic and GABAergic synapses. Moreover, Ca2+-independent spontaneous GABA release was nearly abolished in the hypomorphic unc-64 and snb-1 mutants, suggesting distinct mechanisms for Ca2+-dependent and Ca2+-independent spontaneous release.
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Ablation of All Synaptobrevin vSNAREs Blocks Evoked But Not Spontaneous Neurotransmitter Release at Neuromuscular Synapses. J Neurosci 2019; 39:6049-6066. [PMID: 31160536 DOI: 10.1523/jneurosci.0403-19.2019] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2019] [Revised: 04/26/2019] [Accepted: 05/13/2019] [Indexed: 01/16/2023] Open
Abstract
Synaptic transmission occurs when an action potential triggers neurotransmitter release via the fusion of synaptic vesicles with the presynaptic membrane, driven by the formation of SNARE complexes composed of the vesicular (v)-SNARE synaptobrevin and the target (t)-SNAREs Snap-25 and syntaxin-1. Neurotransmitters are also released spontaneously, independent of an action potential, through the fusion of synaptic vesicles with the presynaptic membrane. The major neuronal vSNAREs, synaptobrevin-1 and synaptobrevin-2, are expressed at the developing neuromuscular junction (NMJ) in mice, but their specific roles in NMJ formation and function remain unclear. Here, we examine the NMJs in mutant mouse embryos lacking either synaptobrevin 1 (Syb1lew/lew ) or synaptobrevin 2 (Syb2 -/-), and those lacking both (Syb1lew/lewSyb2 -/-). We found that, compared with controls: (1) the number and size of NMJs was markedly increased in Syb2 -/- and Syb1lew/lewSyb2 -/- mice, but not in Syb1lew/lew mice; (2) synaptic vesicle density was markedly reduced in Syb1lew/lewSyb2 -/- NMJs; and (3) evoked neurotransmission was markedly reduced in Syb2 -/- NMJs and completely abolished in Syb1lew/lewSyb2 -/- NMJs. Surprisingly, however, spontaneous neurotransmission persists in the absence of both Syb1 and Syb2. Furthermore, spontaneous neurotransmission remains constant in Syb1lew/lewSyb2 -/- NMJs despite changing Ca2+ levels. These findings reveal an overlapping role for Syb1 and Syb2 (with Syb2 being dominant) in developing NMJs in mice. Moreover, because spontaneous release becomes Ca2+-insensitive in Syb1lew/lewSyb2 -/- NMJs, our findings suggest that synaptobrevin-based SNARE complexes play a critical role in conferring Ca2+ sensitivity during spontaneous release.SIGNIFICANCE STATEMENT Neurotransmitters can be released at synapses with (evoked) or without (spontaneous) the influence of action potentials. Whereas evoked neurotransmission requires Ca2+ influx, those underlying the spontaneous neurotransmission may occur with or without Ca2+ Our findings show that, in the absence neuronal vSNARE synaptobrevin-1 and synaptobrevin-2, evoked neurotransmission is completely abolished; however, spontaneous synaptic transmission not only persists but even increased. Furthermore, spontaneous synaptic transmission that is normally highly Ca2+-sensitive became Ca2+-independent upon deletion of vSNARE synaptobrevin-1 and synaptobrevin-2. These findings reveal distinct mechanisms for evoked and spontaneous neurotransmitter release. Moreover, these findings suggest that synaptobrevin-based SNARE complexes play critical roles in conferring Ca2+ sensitivity during spontaneous neurotransmission at developing neuromuscular synapses in mice.
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25
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Wrackmeyer U, Kaldrack J, Jüttner R, Pannasch U, Gimber N, Freiberg F, Purfürst B, Kainmueller D, Schmitz D, Haucke V, Rathjen FG, Gotthardt M. The cell adhesion protein CAR is a negative regulator of synaptic transmission. Sci Rep 2019; 9:6768. [PMID: 31043663 PMCID: PMC6494904 DOI: 10.1038/s41598-019-43150-5] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2018] [Accepted: 04/17/2019] [Indexed: 11/09/2022] Open
Abstract
The Coxsackievirus and adenovirus receptor (CAR) is essential for normal electrical conductance in the heart, but its role in the postnatal brain is largely unknown. Using brain specific CAR knockout mice (KO), we discovered an unexpected role of CAR in neuronal communication. This includes increased basic synaptic transmission at hippocampal Schaffer collaterals, resistance to fatigue, and enhanced long-term potentiation. Spontaneous neurotransmitter release and speed of endocytosis are increased in KOs, accompanied by increased expression of the exocytosis associated calcium sensor synaptotagmin 2. Using proximity proteomics and binding studies, we link CAR to the exocytosis machinery as it associates with syntenin and synaptobrevin/VAMP2 at the synapse. Increased synaptic function does not cause adverse effects in KO mice, as behavior and learning are unaffected. Thus, unlike the connexin-dependent suppression of atrioventricular conduction in the cardiac knockout, communication in the CAR deficient brain is improved, suggesting a role for CAR in presynaptic processes.
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Affiliation(s)
- Uta Wrackmeyer
- Neuromuscular and Cardiovascular Cell Biology, Max Delbrück Center for Molecular Medicine, 13125, Berlin, Germany
| | - Joanna Kaldrack
- Neuromuscular and Cardiovascular Cell Biology, Max Delbrück Center for Molecular Medicine, 13125, Berlin, Germany
| | - René Jüttner
- Neuromuscular and Cardiovascular Cell Biology, Max Delbrück Center for Molecular Medicine, 13125, Berlin, Germany.,Developmental Neurobiology, Max Delbrück Center for Molecular Medicine, 13125, Berlin, Germany
| | - Ulrike Pannasch
- Neuroscience Research Center, Cluster of Excellence NeuroCure, Charité, 10117, Berlin, Germany
| | - Niclas Gimber
- Department of Molecular Pharmacology and Cell Biology, Leibniz Forschungsinstitut für Molekulare Pharmakologie (FMP), 13125, Berlin, Germany
| | - Fabian Freiberg
- Neuromuscular and Cardiovascular Cell Biology, Max Delbrück Center for Molecular Medicine, 13125, Berlin, Germany
| | - Bettina Purfürst
- Core Facility Electron Microscopy, Max Delbrück Center for Molecular Medicine, 13125, Berlin, Germany
| | - Dagmar Kainmueller
- Biomedical Image Analysis, Max Delbrück Center for Molecular Medicine and Berlin Institute of Health, 13125, Berlin, Germany
| | - Dietmar Schmitz
- Neuroscience Research Center, Cluster of Excellence NeuroCure, Charité, 10117, Berlin, Germany
| | - Volker Haucke
- Department of Molecular Pharmacology and Cell Biology, Leibniz Forschungsinstitut für Molekulare Pharmakologie (FMP), 13125, Berlin, Germany
| | - Fritz G Rathjen
- Developmental Neurobiology, Max Delbrück Center for Molecular Medicine, 13125, Berlin, Germany
| | - Michael Gotthardt
- Neuromuscular and Cardiovascular Cell Biology, Max Delbrück Center for Molecular Medicine, 13125, Berlin, Germany.
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26
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Structural maturation of cortical perineuronal nets and their perforating synapses revealed by superresolution imaging. Proc Natl Acad Sci U S A 2019; 116:7071-7076. [PMID: 30890637 DOI: 10.1073/pnas.1817222116] [Citation(s) in RCA: 62] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Parvalbumin-positive (PV+) interneurons play a pivotal role in orchestrating windows of experience-dependent brain plasticity during development. Critical period closure is marked by the condensation of a perineuronal net (PNN) tightly enwrapping subsets of PV+ neurons, both acting as a molecular brake on plasticity and maintaining mature PV+ cell signaling. As much of the molecular organization of PNNs exists at length scales near or below the diffraction limit of light microscopy, we developed a superresolution imaging and analysis platform to visualize the structural organization of PNNs and the synaptic inputs perforating them in primary visual cortex. We identified a structural trajectory of PNN maturation featuring a range of net structures, which was accompanied by an increase in Synaptotagmin-2 (Syt2) signals on PV+ cells suggestive of increased inhibitory input between PV+ neurons. The same structural trajectory was followed by PNNs both during normal development and under conditions of critical period delay by total sensory deprivation or critical period acceleration by deletion of MeCP2, the causative gene for Rett syndrome, despite shifted maturation levels under these perturbations. Notably, superresolution imaging further revealed a decrease in Syt2 signals alongside an increase in vesicular glutamate transporter-2 signals on PV+ cells in MeCP2-deficient animals, suggesting weaker recurrent inhibitory input between PV+ neurons and stronger thalamocortical excitatory inputs onto PV+ cells. These results imply a latent imbalanced circuit signature that might promote cortical silencing in Rett syndrome before the functional regression of vision.
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Shimojo M, Madara J, Pankow S, Liu X, Yates J, Südhof TC, Maximov A. Synaptotagmin-11 mediates a vesicle trafficking pathway that is essential for development and synaptic plasticity. Genes Dev 2019; 33:365-376. [PMID: 30808661 PMCID: PMC6411015 DOI: 10.1101/gad.320077.118] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2018] [Accepted: 12/21/2018] [Indexed: 11/25/2022]
Abstract
Shimojo et al. show that Synaptotagmin-11 is an essential component of a neuronal vesicular trafficking pathway that differs from the well-characterized synaptic vesicle trafficking pathway but is also essential for life. Synaptotagmin-11 (Syt11) is a Synaptotagmin isoform that lacks an apparent ability to bind calcium, phospholipids, or SNARE proteins. While human genetic studies have linked mutations in the Syt11 gene to schizophrenia and Parkinson's disease, the localization or physiological role of Syt11 remain unclear. We found that in neurons, Syt11 resides on abundant vesicles that differ from synaptic vesicles and resemble trafficking endosomes. These vesicles recycle via the plasma membrane in an activity-dependent manner, but their exocytosis is slow and desynchronized. Constitutive knockout mice lacking Syt11 died shortly after birth, suggesting Syt11-mediated membrane transport is required for survival. In contrast, selective ablation of Syt11 in excitatory forebrain neurons using a conditional knockout did not affect life span but impaired synaptic plasticity and memory. Syt11-deficient neurons displayed normal secretion of fast neurotransmitters and peptides but exhibited a reduction of long-term synaptic potentiation. Hence, Syt11 is an essential component of a neuronal vesicular trafficking pathway that differs from the well-characterized synaptic vesicle trafficking pathway but is also essential for life.
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Affiliation(s)
- Masafumi Shimojo
- Department of Neuroscience, Scripps Research, La Jolla, California 92037, USA.,The Dorris Neuroscience, Scripps Research, La Jolla, California 92037, USA
| | - Joseph Madara
- Department of Neuroscience, Scripps Research, La Jolla, California 92037, USA.,The Dorris Neuroscience, Scripps Research, La Jolla, California 92037, USA
| | - Sandra Pankow
- Department of Molecular Medicine, Scripps Research, La Jolla, California 92037, USA
| | - Xinran Liu
- Department of Neuroscience, University of Texas Southwestern Medical Center at Dallas, Dallas 75235, Texas, USA
| | - John Yates
- Department of Molecular Medicine, Scripps Research, La Jolla, California 92037, USA
| | - Thomas C Südhof
- Department of Neuroscience, University of Texas Southwestern Medical Center at Dallas, Dallas 75235, Texas, USA.,Department of Molecular and Cellular Physiology, Stanford University, Palo Alto, California 94035, USA
| | - Anton Maximov
- Department of Neuroscience, Scripps Research, La Jolla, California 92037, USA.,The Dorris Neuroscience, Scripps Research, La Jolla, California 92037, USA.,Department of Neuroscience, University of Texas Southwestern Medical Center at Dallas, Dallas 75235, Texas, USA
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28
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Liu H, Li L, Nedelcu D, Hall Q, Zhou L, Wang W, Yu Y, Kaplan JM, Hu Z. Heterodimerization of UNC-13/RIM regulates synaptic vesicle release probability but not priming in C. elegans. eLife 2019; 8:40585. [PMID: 30802206 PMCID: PMC6389284 DOI: 10.7554/elife.40585] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2018] [Accepted: 02/03/2019] [Indexed: 12/17/2022] Open
Abstract
UNC-13 proteins play an essential role in synaptic transmission by recruiting synaptic vesicles (SVs) to become available for release, which is termed SV priming. Here we show that the C2A domain of UNC-13L, like the corresponding domain in mammalian Munc13-1, displays two conserved binding modes: forming C2A/C2A homodimers, or forming a heterodimer with the zinc finger domain of UNC-10/RIM (C2A/RIM). Functional analysis revealed that UNC-13L’s C2A promotes synaptic transmission by regulating a post-priming process. Stimulus-evoked release but not SV priming, was impaired in unc-10 mutants deficient for C2A/RIM heterodimerization, leading to decreased release probability. Disrupting C2A/C2A homodimerization in UNC-13L-rescued animals had no effect on synaptic transmission, but fully restored the evoked release and the release probability of unc-10/RIM mutants deficient for C2A/RIM heterodimerization. Thus, our results support the model that RIM binding C2A releases UNC-13L from an autoinhibitory homodimeric complex to become fusion-competent by functioning as a switch only.
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Affiliation(s)
- Haowen Liu
- Clem Jones Centre for Ageing Dementia Research, Queensland Brain Institute, The University of Queensland, Brisbane, Australia
| | - Lei Li
- Clem Jones Centre for Ageing Dementia Research, Queensland Brain Institute, The University of Queensland, Brisbane, Australia
| | - Daniel Nedelcu
- Department of Molecular Biology, Massachusetts General Hospital, Boston, United States.,Department of Neurobiology, Harvard Medical School, Boston, United States
| | - Qi Hall
- Department of Molecular Biology, Massachusetts General Hospital, Boston, United States.,Department of Neurobiology, Harvard Medical School, Boston, United States
| | - Lijun Zhou
- Center for Computational and Integrative Biology, Massachusetts General Hospital, Howard Hughes Medical Institute, Boston, United States
| | - Wei Wang
- Clem Jones Centre for Ageing Dementia Research, Queensland Brain Institute, The University of Queensland, Brisbane, Australia
| | - Yi Yu
- Clem Jones Centre for Ageing Dementia Research, Queensland Brain Institute, The University of Queensland, Brisbane, Australia
| | - Joshua M Kaplan
- Department of Neurobiology, Harvard Medical School, Boston, United States
| | - Zhitao Hu
- Clem Jones Centre for Ageing Dementia Research, Queensland Brain Institute, The University of Queensland, Brisbane, Australia
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30
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Takago H, Oshima-Takago T, Moser T. Disruption of Otoferlin Alters the Mode of Exocytosis at the Mouse Inner Hair Cell Ribbon Synapse. Front Mol Neurosci 2019; 11:492. [PMID: 30687007 PMCID: PMC6338019 DOI: 10.3389/fnmol.2018.00492] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2018] [Accepted: 12/19/2018] [Indexed: 11/24/2022] Open
Abstract
Sound encoding relies on Ca2+-mediated exocytosis at the ribbon synapse between cochlear inner hair cells (IHCs) and type I spiral ganglion neurons (SGNs). Otoferlin, a multi-C2 domain protein, is proposed to regulate Ca2+-triggered exocytosis at this synapse, but the precise mechanisms of otoferlin function remain to be elucidated. Here, performing whole-cell voltage-clamp recordings of excitatory postsynaptic currents (EPSCs) from SGNs in otoferlin mutant mice, we investigated the impact of Otof disruption at individual synapses with single release event resolution. Otof deletion decreased the spontaneous release rate and abolished the stimulus-secretion coupling. This was evident from failure of potassium-induced IHC depolarization to stimulate release and supports the proposed role of otoferlin in Ca2+ sensing for fusion. A missense mutation in the Otof gene (pachanga), in which otoferlin level at the IHC plasma membrane was lowered without changing its Ca2+ binding, also reduced the spontaneous release rate but spared the stimulus-secretion coupling. The slowed stimulated release rate supports the hypothesis that a sufficient abundance of otoferlin at the plasma membrane is crucial for the vesicle supply. Large-sized monophasic EPSCs remained present upon Otof deletion despite the drastic reduction of the rate of exocytosis. However, EPSC amplitude, on average, was modestly decreased. Moreover, a reduced contribution of multiphasic EPSC was observed in both Otof mutants. We argue that the presence of large monophasic EPSCs despite the exocytic defect upon Otof deletion supports the uniquantal hypothesis of transmitter release at the IHC ribbon synapse. Based upon the reduced contribution of multiphasic EPSC, we propose a role of otoferlin in regulating the mode of exocytosis in IHCs.
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Affiliation(s)
- Hideki Takago
- Institute for Auditory Neuroscience and InnerEarLab, University Medical Center Göttingen, Göttingen, Germany.,Department of Rehabilitation for Sensory Functions, Research Institute, National Rehabilitation Center for Persons with Disabilities, Saitama, Japan.,Collaborative Research Center 889 Cellular Mechanisms of Sensory Processing, Göttingen, Germany
| | - Tomoko Oshima-Takago
- Institute for Auditory Neuroscience and InnerEarLab, University Medical Center Göttingen, Göttingen, Germany.,Department of Rehabilitation for Sensory Functions, Research Institute, National Rehabilitation Center for Persons with Disabilities, Saitama, Japan.,Collaborative Research Center 889 Cellular Mechanisms of Sensory Processing, Göttingen, Germany.,Göttingen Graduate School for Neurosciences and Molecular Biosciences, University of Göttingen, Göttingen, Germany
| | - Tobias Moser
- Institute for Auditory Neuroscience and InnerEarLab, University Medical Center Göttingen, Göttingen, Germany.,Collaborative Research Center 889 Cellular Mechanisms of Sensory Processing, Göttingen, Germany.,Göttingen Graduate School for Neurosciences and Molecular Biosciences, University of Göttingen, Göttingen, Germany.,Auditory Neuroscience Group, Max Planck Institute for Experimental Medicine, Göttingen, Germany.,Synaptic Nanophysiology Group, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
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31
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Elliott M, Favre-Guilmard C, Liu SM, Maignel J, Masuyer G, Beard M, Boone C, Carré D, Kalinichev M, Lezmi S, Mir I, Nicoleau C, Palan S, Perier C, Raban E, Zhang S, Dong M, Stenmark P, Krupp J. Engineered botulinum neurotoxin B with improved binding to human receptors has enhanced efficacy in preclinical models. SCIENCE ADVANCES 2019; 5:eaau7196. [PMID: 30746458 PMCID: PMC6357751 DOI: 10.1126/sciadv.aau7196] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/09/2018] [Accepted: 12/06/2018] [Indexed: 05/10/2023]
Abstract
Although botulinum neurotoxin serotype A (BoNT/A) products are common treatments for various disorders, there is only one commercial BoNT/B product, whose low potency, likely stemming from low affinity toward its human receptor synaptotagmin 2 (hSyt2), has limited its therapeutic usefulness. We express and characterize two full-length recombinant BoNT/B1 proteins containing designed mutations E1191M/S1199Y (rBoNT/B1MY) and E1191Q/S1199W (rBoNT/B1QW) that enhance binding to hSyt2. In preclinical models including human-induced pluripotent stem cell neurons and a humanized transgenic mouse, this increased hSyt2 affinity results in high potency, comparable to that of BoNT/A. Last, we solve the cocrystal structure of rBoNT/B1MY in complex with peptides of hSyt2 and its homolog hSyt1. We demonstrate that neuronal surface receptor binding limits the clinical efficacy of unmodified BoNT/B and that modified BoNT/B proteins have promising clinical potential.
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MESH Headings
- Animals
- Botulinum Toxins, Type A/chemistry
- Botulinum Toxins, Type A/genetics
- Botulinum Toxins, Type A/metabolism
- Botulinum Toxins, Type A/pharmacology
- Crystallography, X-Ray
- Female
- Glycine/metabolism
- Humans
- Induced Pluripotent Stem Cells/drug effects
- Male
- Mice, Inbred C57BL
- Mice, Transgenic
- Muscle, Skeletal/drug effects
- Muscle, Smooth/drug effects
- Mutation
- Neurons/drug effects
- Neurons/metabolism
- Protein Engineering
- Rabbits
- Rats, Sprague-Dawley
- Recombinant Proteins/genetics
- Recombinant Proteins/metabolism
- Recombinant Proteins/pharmacology
- Static Electricity
- Synaptotagmin II/chemistry
- Synaptotagmin II/genetics
- Synaptotagmin II/metabolism
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Affiliation(s)
- Mark Elliott
- Ipsen Bioinnovation, 102 Park Drive, Milton Park, Abingdon OX14 4RY, UK
| | | | - Sai Man Liu
- Ipsen Bioinnovation, 102 Park Drive, Milton Park, Abingdon OX14 4RY, UK
| | - Jacquie Maignel
- Ipsen Innovation, 5 Avenue du Canada, 91940 Les Ulis, France
| | - Geoffrey Masuyer
- Department of Biochemistry and Biophysics, Stockholm University, Stockholm SE-106 91, Sweden
| | - Matthew Beard
- Ipsen Bioinnovation, 102 Park Drive, Milton Park, Abingdon OX14 4RY, UK
| | - Christopher Boone
- Department of Urology, Boston Children’s Hospital, Department of Microbiology and Immunobiology and Department of Surgery, Harvard Medical School, Boston, MA 02115, USA
| | - Denis Carré
- Ipsen Innovation, 5 Avenue du Canada, 91940 Les Ulis, France
| | | | - Stephane Lezmi
- Ipsen Innovation, 5 Avenue du Canada, 91940 Les Ulis, France
| | - Imran Mir
- Ipsen Bioinnovation, 102 Park Drive, Milton Park, Abingdon OX14 4RY, UK
| | | | - Shilpa Palan
- Ipsen Bioinnovation, 102 Park Drive, Milton Park, Abingdon OX14 4RY, UK
| | - Cindy Perier
- Ipsen Innovation, 5 Avenue du Canada, 91940 Les Ulis, France
| | - Elsa Raban
- Ipsen Innovation, 5 Avenue du Canada, 91940 Les Ulis, France
| | - Sicai Zhang
- Department of Urology, Boston Children’s Hospital, Department of Microbiology and Immunobiology and Department of Surgery, Harvard Medical School, Boston, MA 02115, USA
| | - Min Dong
- Department of Urology, Boston Children’s Hospital, Department of Microbiology and Immunobiology and Department of Surgery, Harvard Medical School, Boston, MA 02115, USA
| | - Pål Stenmark
- Department of Biochemistry and Biophysics, Stockholm University, Stockholm SE-106 91, Sweden
- Department of Experimental Medical Science, Lund University, 221 00 Lund, Sweden
| | - Johannes Krupp
- Ipsen Bioinnovation, 102 Park Drive, Milton Park, Abingdon OX14 4RY, UK
- Ipsen Innovation, 5 Avenue du Canada, 91940 Les Ulis, France
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32
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Brunger AT, Leitz J, Zhou Q, Choi UB, Lai Y. Ca 2+-Triggered Synaptic Vesicle Fusion Initiated by Release of Inhibition. Trends Cell Biol 2018; 28:631-645. [PMID: 29706534 PMCID: PMC6056330 DOI: 10.1016/j.tcb.2018.03.004] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2018] [Revised: 03/17/2018] [Accepted: 03/26/2018] [Indexed: 12/20/2022]
Abstract
Recent structural and functional studies of the synaptic vesicle fusion machinery suggest an inhibited tripartite complex consisting of neuronal soluble N-ethylmaleimide sensitive factor attachment protein receptors (SNAREs), synaptotagmin, and complexin prior to Ca2+-triggered synaptic vesicle fusion. We speculate that Ca2+-triggered fusion commences with the release of inhibition by Ca2+ binding to synaptotagmin C2 domains. Subsequently, fusion is assisted by SNARE complex zippering and by active membrane remodeling properties of synaptotagmin. This additional, inhibitory role of synaptotagmin may be a general principle since other recent studies suggest that Ca2+ binding to extended synaptotagmin C2 domains enables lipid transport by releasing an inhibited state of the system, and that Munc13 may nominally be in an inhibited state, which is released upon Ca2+ binding to one of its C2 domains.
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Affiliation(s)
- Axel T Brunger
- Department of Molecular and Cellular Physiology, Stanford University, Stanford, CA, USA; Department of Neurology and Neurological Sciences, Stanford University, Stanford, CA, USA; Department of Structural Biology, Stanford University, Stanford, CA, USA; Department of Photon Science, Stanford University, Stanford, CA, USA; Howard Hughes Medical Institute, Stanford University, Stanford, CA, USA.
| | - Jeremy Leitz
- Department of Molecular and Cellular Physiology, Stanford University, Stanford, CA, USA; Department of Neurology and Neurological Sciences, Stanford University, Stanford, CA, USA; Department of Structural Biology, Stanford University, Stanford, CA, USA; Department of Photon Science, Stanford University, Stanford, CA, USA; Howard Hughes Medical Institute, Stanford University, Stanford, CA, USA
| | - Qiangjun Zhou
- Department of Molecular and Cellular Physiology, Stanford University, Stanford, CA, USA; Department of Neurology and Neurological Sciences, Stanford University, Stanford, CA, USA; Department of Structural Biology, Stanford University, Stanford, CA, USA; Department of Photon Science, Stanford University, Stanford, CA, USA; Howard Hughes Medical Institute, Stanford University, Stanford, CA, USA
| | - Ucheor B Choi
- Department of Molecular and Cellular Physiology, Stanford University, Stanford, CA, USA; Department of Neurology and Neurological Sciences, Stanford University, Stanford, CA, USA; Department of Structural Biology, Stanford University, Stanford, CA, USA; Department of Photon Science, Stanford University, Stanford, CA, USA; Howard Hughes Medical Institute, Stanford University, Stanford, CA, USA
| | - Ying Lai
- Department of Molecular and Cellular Physiology, Stanford University, Stanford, CA, USA; Department of Neurology and Neurological Sciences, Stanford University, Stanford, CA, USA; Department of Structural Biology, Stanford University, Stanford, CA, USA; Department of Photon Science, Stanford University, Stanford, CA, USA; Howard Hughes Medical Institute, Stanford University, Stanford, CA, USA
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33
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Synergistic control of neurotransmitter release by different members of the synaptotagmin family. Curr Opin Neurobiol 2018; 51:154-162. [DOI: 10.1016/j.conb.2018.05.006] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2018] [Revised: 05/19/2018] [Accepted: 05/21/2018] [Indexed: 01/06/2023]
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34
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Park Y, Ryu JK. Models of synaptotagmin-1 to trigger Ca 2+ -dependent vesicle fusion. FEBS Lett 2018; 592:3480-3492. [PMID: 30004579 DOI: 10.1002/1873-3468.13193] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2018] [Revised: 07/02/2018] [Accepted: 07/06/2018] [Indexed: 11/08/2022]
Abstract
Vesicles in neurons and neuroendocrine cells store neurotransmitters and peptide hormones, which are released by vesicle fusion in response to Ca2+ -evoking stimuli. Synaptotagmin-1 (Syt1), a Ca2+ sensor, mediates ultrafast exocytosis in neurons and neuroendocrine cells. After vesicle docking, Syt1 has two main groups of binding partners: anionic phospholipids and the SNARE (soluble N-ethylmaleimide-sensitive factor attachment protein receptors) complex. The molecular mechanisms by which Syt1 triggers vesicle fusion remain controversial. This Review introduces and summarizes six molecular models of Syt1: (a) Syt1 triggers SNARE unclamping by displacing complexin, (b) Syt1 clamps SNARE zippering, (c) Syt1 causes membrane curvature, (d) membrane bridging by Syt1, (e) Syt1 is a vesicle-plasma membrane distance regulator, and (f) Syt1 undergoes circular oligomerization. We discuss important conditions to test Syt1 activity in vitro and attempt to illustrate the possible roles of Syt1.
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Affiliation(s)
- Yongsoo Park
- Department of Molecular Biology and Genetics, Koç University, Istanbul, Turkey
| | - Je-Kyung Ryu
- Department of Bionanoscience, Kavli Institute of Nanoscience Delft, Delft University of Technology, The Netherlands
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35
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Ge D, Lavidis N. Climatic modulation of neurotransmitter release in amphibian neuromuscular junctions: role of dynorphin-A. Am J Physiol Regul Integr Comp Physiol 2018; 314:R716-R723. [DOI: 10.1152/ajpregu.00263.2017] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Amphibian neuromuscular junctions (NMJs) become relatively more silent during the dry winter season in Australia. During the dry, calcium sensitivity is reduced, whereas calcium dependence remains unchanged. Endogenous opioid peptides play an important role in the regulation of the physiological functions of active and dormant vertebrates. Previous findings suggest that dynorphin-A is more potent than other opiates in decreasing evoked neurotransmission in amphibian NMJs. Dynorphin-A has been shown not to alter the amplitude or the frequency of miniature quantal neurotransmitter release. In the present study, we report that dynorphin-A exerted a more pronounced inhibitory effect on evoked neurotransmitter release during the dry (hibernating period) when compared with the wet (active period) season. Dynorphin-A increased the frequency and decreased the amplitude of miniature neurotransmitter release only at relatively high concentration during the dry season. In the present study, we propose that dynorphin-A suppresses evoked neurotransmitter release and thus contraction of skeletal muscles, while allowing subthreshold activation of the NMJ by miniature neurotransmission, thus preventing any significant neuromuscular remodeling. The inhibitory effect of dynorphin-A on evoked transmitter release is reduced by increasing the extracellular calcium concentration.
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Affiliation(s)
- Dengyun Ge
- School of Biomedical Sciences, The University of Queensland, St. Lucia, Queensland, Australia
| | - Nickolas Lavidis
- School of Biomedical Sciences, The University of Queensland, St. Lucia, Queensland, Australia
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36
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Chen C, Arai I, Satterfield R, Young SM, Jonas P. Synaptotagmin 2 Is the Fast Ca 2+ Sensor at a Central Inhibitory Synapse. Cell Rep 2017; 18:723-736. [PMID: 28099850 PMCID: PMC5276807 DOI: 10.1016/j.celrep.2016.12.067] [Citation(s) in RCA: 52] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2016] [Revised: 11/18/2016] [Accepted: 12/20/2016] [Indexed: 11/24/2022] Open
Abstract
GABAergic synapses in brain circuits generate inhibitory output signals with submillisecond latency and temporal precision. Whether the molecular identity of the release sensor contributes to these signaling properties remains unclear. Here, we examined the Ca2+ sensor of exocytosis at GABAergic basket cell (BC) to Purkinje cell (PC) synapses in cerebellum. Immunolabeling suggested that BC terminals selectively expressed synaptotagmin 2 (Syt2), whereas synaptotagmin 1 (Syt1) was enriched in excitatory terminals. Genetic elimination of Syt2 reduced action potential-evoked release to ∼10%, identifying Syt2 as the major Ca2+ sensor at BC-PC synapses. Differential adenovirus-mediated rescue revealed that Syt2 triggered release with shorter latency and higher temporal precision and mediated faster vesicle pool replenishment than Syt1. Furthermore, deletion of Syt2 severely reduced and delayed disynaptic inhibition following parallel fiber stimulation. Thus, the selective use of Syt2 as release sensor at BC-PC synapses ensures fast and efficient feedforward inhibition in cerebellar microcircuits. Syt2 is the Ca2+ sensor of fast transmitter release at a cerebellar GABAergic synapse Syt2 triggers transmitter release with faster time course than Syt1 Syt2 ensures faster replenishment of the readily releasable pool than Syt1 Syt2 is essential for fast feedforward inhibition in cerebellar microcircuits
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Affiliation(s)
- Chong Chen
- IST Austria (Institute of Science and Technology Austria), Am Campus 1, 3400 Klosterneuburg, Austria
| | - Itaru Arai
- IST Austria (Institute of Science and Technology Austria), Am Campus 1, 3400 Klosterneuburg, Austria
| | - Rachel Satterfield
- Max Planck Florida Institute for Neuroscience, Research Group Molecular Mechanisms of Synaptic Function, Jupiter, FL 33458, USA
| | - Samuel M Young
- Max Planck Florida Institute for Neuroscience, Research Group Molecular Mechanisms of Synaptic Function, Jupiter, FL 33458, USA
| | - Peter Jonas
- IST Austria (Institute of Science and Technology Austria), Am Campus 1, 3400 Klosterneuburg, Austria.
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37
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Exceptionally tight membrane-binding may explain the key role of the synaptotagmin-7 C 2A domain in asynchronous neurotransmitter release. Proc Natl Acad Sci U S A 2017; 114:E8518-E8527. [PMID: 28923929 DOI: 10.1073/pnas.1710708114] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Synaptotagmins (Syts) act as Ca2+ sensors in neurotransmitter release by virtue of Ca2+-binding to their two C2 domains, but their mechanisms of action remain unclear. Puzzlingly, Ca2+-binding to the C2B domain appears to dominate Syt1 function in synchronous release, whereas Ca2+-binding to the C2A domain mediates Syt7 function in asynchronous release. Here we show that crystal structures of the Syt7 C2A domain and C2AB region, and analyses of intrinsic Ca2+-binding to the Syt7 C2 domains using isothermal titration calorimetry, did not reveal major differences that could explain functional differentiation between Syt7 and Syt1. However, using liposome titrations under Ca2+ saturating conditions, we show that the Syt7 C2A domain has a very high membrane affinity and dominates phospholipid binding to Syt7 in the presence or absence of l-α-phosphatidylinositol 4,5-diphosphate (PIP2). For Syt1, the two Ca2+-saturated C2 domains have similar affinities for membranes lacking PIP2, but the C2B domain dominates binding to PIP2-containing membranes. Mutagenesis revealed that the dramatic differences in membrane affinity between the Syt1 and Syt7 C2A domains arise in part from apparently conservative residue substitutions, showing how striking biochemical and functional differences can result from the cumulative effects of subtle residue substitutions. Viewed together, our results suggest that membrane affinity may be a key determinant of the functions of Syt C2 domains in neurotransmitter release.
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Dhara M, Mohrmann R, Bruns D. v-SNARE function in chromaffin cells. Pflugers Arch 2017; 470:169-180. [PMID: 28887593 PMCID: PMC5748422 DOI: 10.1007/s00424-017-2066-z] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2017] [Revised: 08/28/2017] [Accepted: 08/29/2017] [Indexed: 01/04/2023]
Abstract
Vesicle fusion is elementary for intracellular trafficking and release of signal molecules, thus providing the basis for diverse forms of intercellular communication like hormonal regulation or synaptic transmission. A detailed characterization of the mechanisms underlying exocytosis is key to understand how the nervous system integrates information and generates appropriate responses to stimuli. The machinery for vesicular release employs common molecular players in different model systems including neuronal and neuroendocrine cells, in particular members of the SNARE (soluble N-ethylmaleimide-sensitive factor attachment protein receptors) protein family, Sec1/Munc18-like proteins, and other accessory factors. To achieve temporal precision and speed, excitable cells utilize specialized regulatory proteins like synaptotagmin and complexin, whose interplay putatively synchronizes vesicle fusion and enhances stimulus-secretion coupling. In this review, we aim to highlight recent progress and emerging views on the molecular mechanisms, by which constitutively forming SNAREpins are organized in functional, tightly regulated units for synchronized release. Specifically, we will focus on the role of vesicle associated membrane proteins, also referred to as vesicular SNAREs, in fusion and rapid cargo discharge. We will further discuss the functions of SNARE regulators during exocytosis and focus on chromaffin cell as a model system of choice that allows for detailed structure-function analyses and direct measurements of vesicle fusion under precise control of intracellular [Ca]i.
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Affiliation(s)
- Madhurima Dhara
- Molecular Neurophysiology, CIPMM, Medical Faculty, Saarland University, 66421, Homburg/Saar, Germany
| | - Ralf Mohrmann
- Zentrum für Human- und Molekularbiologie, Saarland University, 66421, Homburg/Saar, Germany
| | - Dieter Bruns
- Molecular Neurophysiology, CIPMM, Medical Faculty, Saarland University, 66421, Homburg/Saar, Germany.
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Zhang S, Wang X, Wang X, Shen X, Sun J, Hu X, Chen P. Sr2+has low efficiency in regulating spontaneous release at the Calyx of Held synapses. Synapse 2017; 71. [DOI: 10.1002/syn.21983] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2017] [Revised: 04/24/2017] [Accepted: 04/25/2017] [Indexed: 11/12/2022]
Affiliation(s)
- Shuli Zhang
- Key Laboratory of Animal Models and Human Disease Mechanisms of the Chinese Academy of Sciences & Yunnan Province; Kunming Institute of Zoology, Chinese Academy of Sciences; Kunming Yunnan 650223 China
- State Key Laboratory of Brain and Cognitive Sciences; CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences; Beijing 100101 China
- Kunming College of Life Science; University of Chinese Academy of Sciences; Kunming 650204 China
- University of Chinese Academy of Sciences; Beijing 100049 China
| | - Xuefeng Wang
- State Key Laboratory of Brain and Cognitive Sciences; CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences; Beijing 100101 China
- University of Chinese Academy of Sciences; Beijing 100049 China
| | - Xiaohui Wang
- Department of General Surgery; Xuan Wu Hospital, Capital Medical University; Beijing 100053 China
| | - Xuefeng Shen
- State Key Laboratory of Brain and Cognitive Sciences; CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences; Beijing 100101 China
| | - Jianyuan Sun
- State Key Laboratory of Brain and Cognitive Sciences; CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences; Beijing 100101 China
- Center of Parkinson?s Disease; Beijing Institute for Brain Disorders; Beijing 100053 China
| | - Xintian Hu
- Key Laboratory of Animal Models and Human Disease Mechanisms of the Chinese Academy of Sciences & Yunnan Province; Kunming Institute of Zoology, Chinese Academy of Sciences; Kunming Yunnan 650223 China
- Kunming College of Life Science; University of Chinese Academy of Sciences; Kunming 650204 China
| | - Peihua Chen
- State Key Laboratory of Brain and Cognitive Sciences; CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences; Beijing 100101 China
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Interactions Between SNAP-25 and Synaptotagmin-1 Are Involved in Vesicle Priming, Clamping Spontaneous and Stimulating Evoked Neurotransmission. J Neurosci 2017; 36:11865-11880. [PMID: 27881774 DOI: 10.1523/jneurosci.1011-16.2016] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2016] [Revised: 09/29/2016] [Accepted: 09/29/2016] [Indexed: 01/20/2023] Open
Abstract
Whether interactions between synaptotagmin-1 (syt-1) and the soluble NSF attachment protein receptors (SNAREs) are required during neurotransmission is debated. We examined five SNAP-25 mutations designed to interfere with syt-1 interactions. One mutation, D51/E52/E55A, targeted negative charges within region II of the primary interface (Zhou et al., 2015); two mutations targeted region I (D166A and D166/E170A) and one mutation targeted both (D51/E52/E55/D166A). The final mutation (D186/D193A) targeted C-terminal residues not expected to interact with syt-1. An in vitro assay showed that the region I, region II, and region I+II (D51/E52/E55/D166A) mutants markedly reduced the attachment between syt-1 and t-SNARE-carrying vesicles in the absence of phosphatidylinositol 4,5-bisphosphate [PI(4,5)P2]. In the presence of PI(4,5)P2, vesicle attachment was unaffected by mutation. When expressed in Snap-25-null mouse autaptic neurons, region I mutations reduced the size of the readily releasable pool of vesicles, whereas the region II mutation reduced vesicular release probability. Combining both in the D51/E52/E55/D166A mutation abrogated evoked release. These data point to a division of labor between region I (vesicle priming) and region II (evoked release). Spontaneous release was disinhibited by region I mutations and found to correlate with defective complexin (Cpx) clamping in an in vitro fusion assay, pointing to an interdependent role of synaptotagmin and Cpx in release clamping. Mutation in region II (D51/E52/E55A) also unclamped release, but this effect could be overcome by synaptotagmin overexpression, arguing against an obligatory role in clamping. We conclude that three synaptic release functions of syt-1, vesicle priming, spontaneous release clamping, and evoked release triggering, depend on direct SNARE complex interaction. SIGNIFICANCE STATEMENT The function of synaptotagmin-1 (syt-1):soluble NSF attachment protein receptor (SNARE) interactions during neurotransmission remains unclear. We mutated SNAP-25 within the recently identified region I and region II of the primary synaptotagmin:SNARE interface. Using in vitro assays and rescue experiments in autaptic neurons, we show that interactions within region II of the primary interface are necessary for synchronized calcium-triggered release, whereas region I is involved in vesicle priming. Spontaneous release was disinhibited by region I mutation and found to correlate with defective complexin (Cpx) clamping in vitro, pointing to an interdependent role of synaptotagmin and Cpx in release clamping. Therefore, vesicle priming, clamping spontaneous release, and eliciting evoked release are three different functions of syt-1 that involve different interaction modes with the SNARE complex.
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Hussain S, Egbenya DL, Lai YC, Dosa ZJ, Sørensen JB, Anderson AE, Davanger S. The calcium sensor synaptotagmin 1 is expressed and regulated in hippocampal postsynaptic spines. Hippocampus 2017; 27:1168-1177. [PMID: 28686803 DOI: 10.1002/hipo.22761] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2017] [Revised: 05/31/2017] [Accepted: 06/29/2017] [Indexed: 11/07/2022]
Abstract
Synaptotagmin 1 is a presynaptic calcium sensor, regulating SNARE-mediated vesicle exocytosis of transmitter. Increasing evidence indicate roles of SNARE proteins in postsynaptic glutamate receptor trafficking. However, a possible postsynaptic expression of synaptotagmin 1 has not been demonstrated previously. Here, we used postembedding immunogold electron microscopy to determine the subsynaptic localization of synaptotagmin 1 in rat hippocampal CA1 Schaffer collateral synapses. We report for the first time that synaptotagmin 1 is present in rat hippocampal postsynaptic spines, both on cytoplasmic vesicles and at the postsynaptic density. We further investigated whether postsynaptic synaptotagmin 1 is regulated during synaptic plasticity. In a rat model of chronic temporal lobe epilepsy, we found that presynaptic and postsynaptic concentrations of the protein are reduced compared to control animals. This downregulation may possibly be an adaptive measure to decrease both presynaptic and postsynaptic calcium sensitivity in excitotoxic conditions.
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Affiliation(s)
- Suleman Hussain
- Division of Anatomy, Department of Molecular Medicine, Institute of Basic Medical Sciences, University of Oslo, Norway
| | - Daniel Lawer Egbenya
- Division of Anatomy, Department of Molecular Medicine, Institute of Basic Medical Sciences, University of Oslo, Norway
| | - Yi-Chen Lai
- Jan and Dan Duncan Neurological Research Institute, Baylor College of Medicine, Houston, Texas, USA
| | - Zita J Dosa
- Department of Neuroscience and Pharmacology, Faculty of Health and Medical Sciences, Lundbeck Foundation Center for Biomembranes in Nanomedicine, University of Copenhagen, Denmark
| | - Jakob B Sørensen
- Department of Neuroscience and Pharmacology, Faculty of Health and Medical Sciences, Lundbeck Foundation Center for Biomembranes in Nanomedicine, University of Copenhagen, Denmark
| | - Anne E Anderson
- Jan and Dan Duncan Neurological Research Institute, Baylor College of Medicine, Houston, Texas, USA
| | - Svend Davanger
- Division of Anatomy, Department of Molecular Medicine, Institute of Basic Medical Sciences, University of Oslo, Norway
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Tong XJ, López-Soto EJ, Li L, Liu H, Nedelcu D, Lipscombe D, Hu Z, Kaplan JM. Retrograde Synaptic Inhibition Is Mediated by α-Neurexin Binding to the α2δ Subunits of N-Type Calcium Channels. Neuron 2017; 95:326-340.e5. [PMID: 28669545 DOI: 10.1016/j.neuron.2017.06.018] [Citation(s) in RCA: 74] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2017] [Revised: 04/20/2017] [Accepted: 06/08/2017] [Indexed: 12/31/2022]
Abstract
The synaptic adhesion molecules Neurexin and Neuroligin alter the development and function of synapses and are linked to autism in humans. In C. elegans, post-synaptic Neurexin (NRX-1) and pre-synaptic Neuroligin (NLG-1) mediate a retrograde synaptic signal that inhibits acetylcholine (ACh) release at neuromuscular junctions. Here, we show that the retrograde signal decreases ACh release by inhibiting the function of pre-synaptic UNC-2/CaV2 calcium channels. Post-synaptic NRX-1 binds to an auxiliary subunit of pre-synaptic UNC-2/CaV2 channels (UNC-36/α2δ), decreasing UNC-36 abundance at pre-synaptic elements. Retrograde inhibition is mediated by a soluble form of NRX-1's ectodomain, which is released from the post-synaptic membrane by the SUP-17/ADAM10 protease. Mammalian Neurexin-1α binds α2δ-3 and decreases CaV2.2 current in transfected cells, whereas Neurexin-1α has no effect on CaV2.2 reconstituted with α2δ-1 and α2δ-2. Collectively, these results suggest that α-Neurexin binding to α2δ is a conserved mechanism for regulating synaptic transmission.
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Affiliation(s)
- Xia-Jing Tong
- Department of Molecular Biology, Massachusetts General Hospital, Boston, MA 02114, USA; Department of Neurobiology, Harvard Medical School, Boston, MA 02115, USA
| | - Eduardo Javier López-Soto
- Department of Neuroscience and Brown Institute for Brain Science, Brown University, Providence, RI 02912, USA
| | - Lei Li
- Clem Jones Centre for Ageing Dementia Research, Queensland Brain Institute, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Haowen Liu
- Clem Jones Centre for Ageing Dementia Research, Queensland Brain Institute, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Daniel Nedelcu
- Department of Molecular Biology, Massachusetts General Hospital, Boston, MA 02114, USA; Department of Neurobiology, Harvard Medical School, Boston, MA 02115, USA
| | - Diane Lipscombe
- Department of Neuroscience and Brown Institute for Brain Science, Brown University, Providence, RI 02912, USA
| | - Zhitao Hu
- Clem Jones Centre for Ageing Dementia Research, Queensland Brain Institute, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Joshua M Kaplan
- Department of Molecular Biology, Massachusetts General Hospital, Boston, MA 02114, USA; Department of Neurobiology, Harvard Medical School, Boston, MA 02115, USA; Program in Neuroscience, Harvard Medical School, Boston, MA 02115, USA.
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43
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Luo F, Südhof TC. Synaptotagmin-7-Mediated Asynchronous Release Boosts High-Fidelity Synchronous Transmission at a Central Synapse. Neuron 2017; 94:826-839.e3. [DOI: 10.1016/j.neuron.2017.04.020] [Citation(s) in RCA: 73] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2016] [Revised: 03/31/2017] [Accepted: 04/13/2017] [Indexed: 11/17/2022]
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Synaptotagmin2 (Syt2) Drives Fast Release Redundantly with Syt1 at the Output Synapses of Parvalbumin-Expressing Inhibitory Neurons. J Neurosci 2017; 37:4604-4617. [PMID: 28363983 DOI: 10.1523/jneurosci.3736-16.2017] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2016] [Revised: 03/22/2017] [Accepted: 03/27/2017] [Indexed: 12/16/2022] Open
Abstract
Parvalbumin-expressing inhibitory neurons in the mammalian CNS are specialized for fast transmitter release at their output synapses. However, the Ca2+ sensor(s) used by identified inhibitory synapses, including the output synapses of parvalbumin-expressing inhibitory neurons, have only recently started to be addressed. Here, we investigated the roles of Syt1 and Syt2 at two types of fast-releasing inhibitory connections in the mammalian CNS: the medial nucleus of the trapezoid body to lateral superior olive glycinergic synapse, and the basket/stellate cell-Purkinje GABAergic synapse in the cerebellum. We used conditional and conventional knock-out (KO) mouse lines, with viral expression of Cre-recombinase and a light-activated ion channel for optical stimulation of the transduced fibers, to produce Syt1-Syt2 double KO synapses in vivo Surprisingly, we found that KO of Syt2 alone had only minor effects on evoked transmitter release, despite the clear presence of the protein in inhibitory nerve terminals revealed by immunohistochemistry. We show that Syt1 is weakly coexpressed at these inhibitory synapses and must be genetically inactivated together with Syt2 to achieve a significant reduction and desynchronization of fast release. Thus, our work identifies the functionally relevant Ca2+ sensor(s) at fast-releasing inhibitory synapses and shows that two major Syt isoforms can cooperate to mediate release at a given synaptic connection.SIGNIFICANCE STATEMENT During synaptic transmission, the influx of Ca2+ into the presynaptic nerve terminal activates a Ca2+ sensor for vesicle fusion, a crucial step in the activity-dependent release of neurotransmitter. Synaptotagmin (Syt) proteins, and especially Syt1 and Syt2, have been identified as the Ca2+ sensor at excitatory synapses, but the Ca2+ sensor(s) at inhibitory synapses in native brain tissue are not well known. We found that both Syt1 and Syt2 need to be genetically inactivated to cause a significant reduction of activity-evoked release at two types of fast inhibitory synapses in mouse brain. Thus, we identify Syt2 as a functionally important Ca2+ sensor at fast-releasing inhibitory synapses, and show that Syt1 and Syt2 can redundantly control transmitter release at specific brain synapses.
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45
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Erro R, Bhatia KP, Espay AJ, Striano P. The epileptic and nonepileptic spectrum of paroxysmal dyskinesias: Channelopathies, synaptopathies, and transportopathies. Mov Disord 2017; 32:310-318. [PMID: 28090678 DOI: 10.1002/mds.26901] [Citation(s) in RCA: 52] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2016] [Revised: 11/28/2016] [Accepted: 12/01/2016] [Indexed: 12/12/2022] Open
Abstract
Historically, the syndrome of primary paroxysmal dyskinesias was considered a group of disorders as a result of ion channel dysfunction. This proposition was primarily based on the discovery of mutations in ion channels, which caused other episodic neurological disorders such as epilepsy and migraine and also supported by the frequent association between paroxysmal dyskinesias and epilepsy. However, the discovery of the genes responsible for the 3 classic forms of paroxysmal dyskinesias disproved this ion channel theory. On the other hand, novel gene mutations implicating ion channels have been recently reported to produce episodic movement disorders clinically similar to the classic paroxysmal dyskinesias. Here, we review the clinical and pathophysiological aspects of the paroxysmal dyskinesias, further proposing a pathophysiological framework according to which they can be classified as synaptopathies (proline-rich transmembrane protein 2 and myofibrillogenesis regulator gene), channelopathies (calcium-activated potassium channel subunit alpha-1 and voltage-gated sodium channel type 8), or transportopathies (solute carrier family 2 member 1). This proposal might serve to explain similarities and differences among the various paroxysmal dyskinesias in terms of clinical features, treatment response, and natural history. © 2017 International Parkinson and Movement Disorder Society.
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Affiliation(s)
- Roberto Erro
- Sobell Department of Motor Neuroscience and Movement Disorders, University College London, Institute of Neurology, London, UK.,Department of Neuroscience, Biomedicine and Movement Science, University of Verona, Verona, Italy
| | - Kailash P Bhatia
- Sobell Department of Motor Neuroscience and Movement Disorders, University College London, Institute of Neurology, London, UK
| | - Alberto J Espay
- Gardner Neuroscience Institute, Department of Neurology, Gardner Center for Parkinson's disease and Movement Disorders, University of Cincinnati, Ohio, USA
| | - Pasquale Striano
- Pediatric Neurology and Muscular Diseases Unit, Department of Neurosciences, Rehabilitation, Ophthalmology, Genetics, Maternal and Child Health, University of Genoa, "G. Gaslini" Institute, Genova, Italy
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MOCHIDA S. Millisecond Ca 2+ dynamics activate multiple protein cascades for synaptic vesicle control. PROCEEDINGS OF THE JAPAN ACADEMY. SERIES B, PHYSICAL AND BIOLOGICAL SCIENCES 2017; 93:802-820. [PMID: 29225307 PMCID: PMC5790758 DOI: 10.2183/pjab.93.050] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/28/2017] [Accepted: 08/21/2017] [Indexed: 06/07/2023]
Abstract
For reliable transmission at chemical synapses, neurotransmitters must be released dynamically in response to neuronal activity in the form of action potentials. Stable synaptic transmission is dependent on the efficacy of transmitter release and the rate of resupplying synaptic vesicles to their release sites. Accurate regulation is conferred by proteins sensing Ca2+ entering through voltage-gated Ca2+ channels opened by an action potential. Presynaptic Ca2+ concentration changes are dynamic functions in space and time, with wide fluctuations associated with different rates of neuronal activity. Thus, regulation of transmitter release includes reactions involving multiple Ca2+-dependent proteins, each operating over a specific time window. Classically, studies of presynaptic proteins function favored large invertebrate presynaptic terminals. I have established a useful mammalian synapse model based on sympathetic neurons in culture. This review summarizes the use of this model synapse to study the roles of presynaptic proteins in neuronal activity for the control of transmitter release efficacy and synaptic vesicle recycling.
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Affiliation(s)
- Sumiko MOCHIDA
- Department of Physiology, Tokyo Medical University, Tokyo, Japan
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47
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Pinheiro PS, Houy S, Sørensen JB. C2-domain containing calcium sensors in neuroendocrine secretion. J Neurochem 2016; 139:943-958. [DOI: 10.1111/jnc.13865] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2016] [Revised: 09/17/2016] [Accepted: 10/05/2016] [Indexed: 12/11/2022]
Affiliation(s)
- Paulo S. Pinheiro
- Center for Neuroscience and Cell Biology; University of Coimbra; Coimbra Portugal
| | - Sébastien Houy
- Department of Neuroscience and Pharmacology; Faculty of Health and Medical Sciences; University of Copenhagen; Copenhagen Denmark
| | - Jakob B. Sørensen
- Department of Neuroscience and Pharmacology; Faculty of Health and Medical Sciences; University of Copenhagen; Copenhagen Denmark
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Poon VY, Gu M, Ji F, VanDongen AM, Fivaz M. miR-27b shapes the presynaptic transcriptome and influences neurotransmission by silencing the polycomb group protein Bmi1. BMC Genomics 2016; 17:777. [PMID: 27716060 PMCID: PMC5050705 DOI: 10.1186/s12864-016-3139-7] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2016] [Accepted: 09/28/2016] [Indexed: 12/02/2022] Open
Abstract
Background MicroRNAs (miRNAs) are short non-coding RNAs that are emerging as important post-transcriptional regulators of neuronal and synaptic development. The precise impact of miRNAs on presynaptic function and neurotransmission remains, however, poorly understood. Results Here, we identify miR-27b—an abundant neuronal miRNA implicated in neurological disorders—as a global regulator of the presynaptic transcriptome. miR-27b influences the expression of three quarters of genes associated with presynaptic function in cortical neurons. Contrary to expectation, a large majority of these genes are up-regulated by miR-27b. This stimulatory effect is mediated by miR-27b-directed silencing of several transcriptional repressors that cooperate to suppress the presynaptic transcriptome. The strongest repressive activity appears to be mediated by Bmi1, a component of the polycomb repressive complex implicated in self-renewal of neural stem cells. miR-27b knockdown leads to reduced synaptogenesis and to a marked decrease in neural network activity, which is fully restored by RNAi-mediated silencing of Bmi1. Conclusions We conclude that silencing of Bmi1 by miR-27b relieves repression of the presynaptic transcriptome and supports neurotransmission in cortical networks. These results expand the repressive activity of Bmi1 to genes involved in synaptic function and identify a unique post-transcriptional circuitry that stimulates expression of synaptic genes and promotes synapse differentiation. Electronic supplementary material The online version of this article (doi:10.1186/s12864-016-3139-7) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Vivian Y Poon
- Program in Neuroscience and Behavioral Disorders, Duke-NUS Medical School, Singapore, Singapore
| | - Minxia Gu
- Program in Neuroscience and Behavioral Disorders, Duke-NUS Medical School, Singapore, Singapore
| | - Fang Ji
- Program in Neuroscience and Behavioral Disorders, Duke-NUS Medical School, Singapore, Singapore
| | - Antonius M VanDongen
- Program in Neuroscience and Behavioral Disorders, Duke-NUS Medical School, Singapore, Singapore
| | - Marc Fivaz
- Program in Neuroscience and Behavioral Disorders, Duke-NUS Medical School, Singapore, Singapore. .,Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore.
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Kochubey O, Babai N, Schneggenburger R. A Synaptotagmin Isoform Switch during the Development of an Identified CNS Synapse. Neuron 2016; 90:984-99. [DOI: 10.1016/j.neuron.2016.04.038] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2015] [Revised: 02/26/2016] [Accepted: 04/20/2016] [Indexed: 01/08/2023]
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50
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Okamoto Y, Lipstein N, Hua Y, Lin KH, Brose N, Sakaba T, Midorikawa M. Distinct modes of endocytotic presynaptic membrane and protein uptake at the calyx of Held terminal of rats and mice. eLife 2016; 5. [PMID: 27154627 PMCID: PMC4927297 DOI: 10.7554/elife.14643] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2016] [Accepted: 05/06/2016] [Indexed: 11/15/2022] Open
Abstract
Neurotransmitter is released at synapses by fusion of synaptic vesicles with the plasma membrane. To sustain synaptic transmission, compensatory retrieval of membranes and vesicular proteins is essential. We combined capacitance measurements and pH-imaging via pH-sensitive vesicular protein marker (anti-synaptotagmin2-cypHer5E), and compared the retrieval kinetics of membranes and vesicular proteins at the calyx of Held synapse. Membrane and Syt2 were retrieved with a similar time course when slow endocytosis was elicited. When fast endocytosis was elicited, Syt2 was still retrieved together with the membrane, but endocytosed organelle re-acidification was slowed down, which provides strong evidence for two distinct endocytotic pathways. Strikingly, CaM inhibitors or the inhibition of the Ca2+-calmodulin-Munc13-1 signaling pathway only impaired the uptake of Syt2 while leaving membrane retrieval intact, indicating different recycling mechanisms for membranes and vesicle proteins. Our data identify a novel mechanism of stimulus- and Ca2+-dependent regulation of coordinated endocytosis of synaptic membranes and vesicle proteins. DOI:http://dx.doi.org/10.7554/eLife.14643.001 Nerve cells release chemicals called neurotransmitters to communicate with each other. The neurotransmitters are packaged inside membrane-encased sacs called vesicles that fuse with the cell’s membrane and release their contents into the space between the nerve cells. The vesicle membrane (which also has proteins embedded in it) can then be retrieved into the cell, and recycled to make new vesicles ready to release more neurotransmitters. Recycling vesicle components requires highly coordinated mechanisms that regulate how much membrane and vesicle protein is retrieved from the cell membrane. Researchers interested in these processes have often studied them at a part of the brainstem of mammals known as the calyx of Held. However, many of the details about how vesicle proteins are recycled remained unclear. Okamoto et al. have now measured vesicle membrane and protein retrieval at the same time and in the same cell at the calyx of Held from rats and mice. The cell surface area was also measured, and the experiments focused on a fluorescently tagged version of a vesicle protein called Synaptotagmin2 that could be tracked under a microscope. Okamoto et al. found that, in weakly active nerve cells, the vesicle membrane and Synaptotagmin2 were retrieved together at a slow rate. The process was faster in more active nerve cells, and Synaptotagmin2 was still retrieved with the membrane but it appeared to be stored first in larger sacs. This suggests that membrane and vesicle proteins may be retrieved via two distinct modes depending on the activity strength. The results of further experiments went on to suggest that vesicle membranes might be recycled in a different way from vesicle proteins. Finally, Okamoto et al. also found a signaling pathway that couples the uptake of vesicle membrane with uptake of Synaptotagmin2. Future studies could now explore how these processes work in other types of nerve cell. DOI:http://dx.doi.org/10.7554/eLife.14643.002
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Affiliation(s)
- Yuji Okamoto
- Graduate School of Brain Science, Doshisha University, Kyoto, Japan
| | - Noa Lipstein
- Department of Molecular Neurobiology, Max Planck Institute of Experimental Medicine, Göttingen, Germany
| | - Yunfeng Hua
- Department of Connectomics, Max Planck Institute of Brain Research, Frankfurt, Germany.,Max-Planck-Institute for Biophysical Chemistry, Göttingen, Germany
| | - Kun-Han Lin
- Max-Planck-Institute for Biophysical Chemistry, Göttingen, Germany
| | - Nils Brose
- Department of Molecular Neurobiology, Max Planck Institute of Experimental Medicine, Göttingen, Germany
| | - Takeshi Sakaba
- Graduate School of Brain Science, Doshisha University, Kyoto, Japan
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