1
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Chin M, Kaeser PS. The intracellular C-terminus confers compartment-specific targeting of voltage-gated calcium channels. Cell Rep 2024; 43:114428. [PMID: 38996073 DOI: 10.1016/j.celrep.2024.114428] [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: 12/28/2023] [Revised: 06/07/2024] [Accepted: 06/18/2024] [Indexed: 07/14/2024] Open
Abstract
To achieve the functional polarization that underlies brain computation, neurons sort protein material into distinct compartments. Ion channel composition, for example, differs between axons and dendrites, but the molecular determinants for their polarized trafficking remain obscure. Here, we identify mechanisms that target voltage-gated Ca2+ channels (CaVs) to distinct subcellular compartments. In hippocampal neurons, CaV2s trigger neurotransmitter release at the presynaptic active zone, and CaV1s localize somatodendritically. After knockout of all three CaV2s, expression of CaV2.1, but not CaV1.3, restores neurotransmitter release. We find that chimeric CaV1.3s with CaV2.1 intracellular C-termini localize to the active zone, mediate synaptic vesicle exocytosis, and render release sensitive to CaV1 blockers. This dominant targeting function of the CaV2.1 C-terminus requires the first EF hand in its proximal segment, and replacement of the CaV2.1 C-terminus with that of CaV1.3 abolishes CaV2.1 active zone localization and function. We conclude that CaV intracellular C-termini mediate compartment-specific targeting.
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Affiliation(s)
- Morven Chin
- Department of Neurobiology, Harvard Medical School, Boston, MA 02115, USA
| | - Pascal S Kaeser
- Department of Neurobiology, Harvard Medical School, Boston, MA 02115, USA.
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2
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Martín-Belmonte A, Aguado C, Alfaro-Ruiz R, Kulik A, de la Ossa L, Moreno-Martínez AE, Alberquilla S, García-Carracedo L, Fernández M, Fajardo-Serrano A, Aso E, Shigemoto R, Martín ED, Fukazawa Y, Ciruela F, Luján R. Nanoarchitecture of Ca V2.1 channels and GABA B receptors in the mouse hippocampus: Impact of APP/PS1 pathology. Brain Pathol 2024:e13279. [PMID: 38887180 DOI: 10.1111/bpa.13279] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2024] [Accepted: 05/27/2024] [Indexed: 06/20/2024] Open
Abstract
Voltage-gated CaV2.1 (P/Q-type) Ca2+ channels play a crucial role in regulating neurotransmitter release, thus contributing to synaptic plasticity and to processes such as learning and memory. Despite their recognized importance in neural function, there is limited information on their potential involvement in neurodegenerative conditions such as Alzheimer's disease (AD). Here, we aimed to explore the impact of AD pathology on the density and nanoscale compartmentalization of CaV2.1 channels in the hippocampus in association with GABAB receptors. Histoblotting experiments showed that the density of CaV2.1 channel was significantly reduced in the hippocampus of APP/PS1 mice in a laminar-dependent manner. CaV2.1 channel was enriched in the active zone of the axon terminals and was present at a very low density over the surface of dendritic tree of the CA1 pyramidal cells, as shown by quantitative SDS-digested freeze-fracture replica labelling (SDS-FRL). In APP/PS1 mice, the density of CaV2.1 channel in the active zone was significantly reduced in the strata radiatum and lacunosum-moleculare, while it remained unaltered in the stratum oriens. The decline in Cav2.1 channel density was found to be associated with a corresponding impairment in the GABAergic synaptic function, as evidenced by electrophysiological experiments carried out in the hippocampus of APP/PS1 mice. Remarkably, double SDS-FRL showed a co-clustering of CaV2.1 channel and GABAB1 receptor in nanodomains (~40-50 nm) in wild type mice, while in APP/PS1 mice this nanoarchitecture was absent. Together, these findings suggest that the AD pathology-induced reduction in CaV2.1 channel density and CaV2.1-GABAB1 de-clustering may play a role in the synaptic transmission alterations shown in the AD hippocampus. Therefore, uncovering these layer-dependent changes in P/Q calcium currents associated with AD pathology can benefit the development of future strategies for AD management.
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Affiliation(s)
- Alejandro Martín-Belmonte
- Departamento de Ciencias Médicas, Facultad de Medicina, Synaptic Structure Laboratory, Instituto de Biomedicina de la UCLM (IB-UCLM), Universidad Castilla-La Mancha, Albacete, Spain
- Pharmacology Unit, Department of Pathology and Experimental Therapeutics, Faculty of Medicine and Health Sciences, Institute of Neurosciences, University of Barcelona, Barcelona, Spain
- Neuropharmacology and Pain Group, Neuroscience Program, Institut d'Investigació Biomèdica de Bellvitge, Barcelona, Spain
| | - Carolina Aguado
- Departamento de Ciencias Médicas, Facultad de Medicina, Synaptic Structure Laboratory, Instituto de Biomedicina de la UCLM (IB-UCLM), Universidad Castilla-La Mancha, Albacete, Spain
- Laboratorio de Estructura Sináptica, Instituto de Investigación Sanitaria de Castilla-La Mancha (IDISCAM), Albacete, Spain
| | - Rocío Alfaro-Ruiz
- Departamento de Ciencias Médicas, Facultad de Medicina, Synaptic Structure Laboratory, Instituto de Biomedicina de la UCLM (IB-UCLM), Universidad Castilla-La Mancha, Albacete, Spain
- Laboratorio de Estructura Sináptica, Instituto de Investigación Sanitaria de Castilla-La Mancha (IDISCAM), Albacete, Spain
| | - Akos Kulik
- Institute for Physiology II, Medical Faculty, University of Freiburg, Freiburg, Germany
| | - Luis de la Ossa
- Departamento de Sistemas Informáticos, Escuela Superior de Ingeniería Informática, Universidad de Castilla-La Mancha, Albacete, Spain
| | - Ana Esther Moreno-Martínez
- Departamento de Ciencias Médicas, Facultad de Medicina, Synaptic Structure Laboratory, Instituto de Biomedicina de la UCLM (IB-UCLM), Universidad Castilla-La Mancha, Albacete, Spain
- Laboratorio de Estructura Sináptica, Instituto de Investigación Sanitaria de Castilla-La Mancha (IDISCAM), Albacete, Spain
| | - Samuel Alberquilla
- Laboratory of Neurophysiology and Synaptic Plasticity, Instituto Cajal, Consejo Superior de Investigaciones Científicas, Madrid, Spain
| | - Lucía García-Carracedo
- Laboratory of Neurophysiology and Synaptic Plasticity, Instituto Cajal, Consejo Superior de Investigaciones Científicas, Madrid, Spain
| | - Miriam Fernández
- Departamento de Ciencias Médicas, Facultad de Medicina, Synaptic Structure Laboratory, Instituto de Biomedicina de la UCLM (IB-UCLM), Universidad Castilla-La Mancha, Albacete, Spain
- Laboratorio de Estructura Sináptica, Instituto de Investigación Sanitaria de Castilla-La Mancha (IDISCAM), Albacete, Spain
| | - Ana Fajardo-Serrano
- Departamento de Ciencias Médicas, Facultad de Medicina, Synaptic Structure Laboratory, Instituto de Biomedicina de la UCLM (IB-UCLM), Universidad Castilla-La Mancha, Albacete, Spain
| | - Ester Aso
- Pharmacology Unit, Department of Pathology and Experimental Therapeutics, Faculty of Medicine and Health Sciences, Institute of Neurosciences, University of Barcelona, Barcelona, Spain
- Neuropharmacology and Pain Group, Neuroscience Program, Institut d'Investigació Biomèdica de Bellvitge, Barcelona, Spain
| | - Ryuichi Shigemoto
- Institute of Science and Technology Austria (ISTA), Klosterneuburg, Austria
| | - Eduardo D Martín
- Laboratory of Neurophysiology and Synaptic Plasticity, Instituto Cajal, Consejo Superior de Investigaciones Científicas, Madrid, Spain
| | - Yugo Fukazawa
- Division of Brain Structure and Function, Faculty of Medical Science, University of Fukui, Fukui, Japan
- Life Science Innovation Center, University of Fukui, Fukui, Japan
| | - Francisco Ciruela
- Pharmacology Unit, Department of Pathology and Experimental Therapeutics, Faculty of Medicine and Health Sciences, Institute of Neurosciences, University of Barcelona, Barcelona, Spain
- Neuropharmacology and Pain Group, Neuroscience Program, Institut d'Investigació Biomèdica de Bellvitge, Barcelona, Spain
| | - Rafael Luján
- Departamento de Ciencias Médicas, Facultad de Medicina, Synaptic Structure Laboratory, Instituto de Biomedicina de la UCLM (IB-UCLM), Universidad Castilla-La Mancha, Albacete, Spain
- Laboratorio de Estructura Sináptica, Instituto de Investigación Sanitaria de Castilla-La Mancha (IDISCAM), Albacete, Spain
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3
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Brockhaus J, Kahl I, Ahmad M, Repetto D, Reissner C, Missler M. Conditional Knockout of Neurexins Alters the Contribution of Calcium Channel Subtypes to Presynaptic Ca 2+ Influx. Cells 2024; 13:981. [PMID: 38891114 PMCID: PMC11171642 DOI: 10.3390/cells13110981] [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: 05/02/2024] [Revised: 05/23/2024] [Accepted: 06/03/2024] [Indexed: 06/21/2024] Open
Abstract
Presynaptic Ca2+ influx through voltage-gated Ca2+ channels (VGCCs) is a key signal for synaptic vesicle release. Synaptic neurexins can partially determine the strength of transmission by regulating VGCCs. However, it is unknown whether neurexins modulate Ca2+ influx via all VGCC subtypes similarly. Here, we performed live cell imaging of synaptic boutons from primary hippocampal neurons with a Ca2+ indicator. We used the expression of inactive and active Cre recombinase to compare control to conditional knockout neurons lacking either all or selected neurexin variants. We found that reduced total presynaptic Ca2+ transients caused by the deletion of all neurexins were primarily due to the reduced contribution of P/Q-type VGCCs. The deletion of neurexin1α alone also reduced the total presynaptic Ca2+ influx but increased Ca2+ influx via N-type VGCCs. Moreover, we tested whether the decrease in Ca2+ influx induced by activation of cannabinoid receptor 1 (CB1-receptor) is modulated by neurexins. Unlike earlier observations emphasizing a role for β-neurexins, we found that the decrease in presynaptic Ca2+ transients induced by CB1-receptor activation depended more strongly on the presence of α-neurexins in hippocampal neurons. Together, our results suggest that neurexins have unique roles in the modulation of presynaptic Ca2+ influx through VGCC subtypes and that different neurexin variants may affect specific VGCCs.
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Affiliation(s)
- Johannes Brockhaus
- Institute of Anatomy and Molecular Neurobiology, University of Münster, 48149 Münster, Germany
| | - Iris Kahl
- Institute of Anatomy and Molecular Neurobiology, University of Münster, 48149 Münster, Germany
| | - Mohiuddin Ahmad
- Institute of Anatomy and Molecular Neurobiology, University of Münster, 48149 Münster, Germany
- Department of Cell Biology, College of Medicine, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA
| | - Daniele Repetto
- Institute of Anatomy and Molecular Neurobiology, University of Münster, 48149 Münster, Germany
| | - Carsten Reissner
- Institute of Anatomy and Molecular Neurobiology, University of Münster, 48149 Münster, Germany
| | - Markus Missler
- Institute of Anatomy and Molecular Neurobiology, University of Münster, 48149 Münster, Germany
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4
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Trovò L, Kouvaros S, Schwenk J, Fernandez-Fernandez D, Fritzius T, Rem PD, Früh S, Gassmann M, Fakler B, Bischofberger J, Bettler B. Synaptotagmin-11 facilitates assembly of a presynaptic signaling complex in post-Golgi cargo vesicles. EMBO Rep 2024; 25:2610-2634. [PMID: 38698221 PMCID: PMC11169412 DOI: 10.1038/s44319-024-00147-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2023] [Revised: 04/11/2024] [Accepted: 04/12/2024] [Indexed: 05/05/2024] Open
Abstract
GABAB receptors (GBRs), the G protein-coupled receptors for GABA, regulate synaptic transmission throughout the brain. A main synaptic function of GBRs is the gating of Cav2.2-type Ca2+ channels. However, the cellular compartment where stable GBR/Cav2.2 signaling complexes form remains unknown. In this study, we demonstrate that the vesicular protein synaptotagmin-11 (Syt11) binds to both the auxiliary GBR subunit KCTD16 and Cav2.2 channels. Through these dual interactions, Syt11 recruits GBRs and Cav2.2 channels to post-Golgi vesicles, thus facilitating assembly of GBR/Cav2.2 signaling complexes. In addition, Syt11 stabilizes GBRs and Cav2.2 channels at the neuronal plasma membrane by inhibiting constitutive internalization. Neurons of Syt11 knockout mice exhibit deficits in presynaptic GBRs and Cav2.2 channels, reduced neurotransmitter release, and decreased GBR-mediated presynaptic inhibition, highlighting the critical role of Syt11 in the assembly and stable expression of GBR/Cav2.2 complexes. These findings support that Syt11 acts as a vesicular scaffold protein, aiding in the assembly of signaling complexes from low-abundance components within transport vesicles. This mechanism enables insertion of pre-assembled functional signaling units into the synaptic membrane.
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Affiliation(s)
- Luca Trovò
- Department of Biomedicine, University of Basel, Basel, Switzerland
| | | | - Jochen Schwenk
- Institute of Physiology, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | | | | | | | - Simon Früh
- Department of Biomedicine, University of Basel, Basel, Switzerland
| | - Martin Gassmann
- Department of Biomedicine, University of Basel, Basel, Switzerland
| | - Bernd Fakler
- Institute of Physiology, Faculty of Medicine, University of Freiburg, Freiburg, Germany
- CIBSS Center for Integrative Biological Signalling Studies, University of Freiburg, Freiburg, Germany
- Center for Basics in NeuroModulation, Freiburg, Germany
| | | | - Bernhard Bettler
- Department of Biomedicine, University of Basel, Basel, Switzerland.
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5
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Zhong R, Rua MT, Wei-LaPierre L. Targeting mitochondrial Ca 2+ uptake for the treatment of amyotrophic lateral sclerosis. J Physiol 2024; 602:1519-1549. [PMID: 38010626 PMCID: PMC11032238 DOI: 10.1113/jp284143] [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: 09/06/2023] [Accepted: 10/31/2023] [Indexed: 11/29/2023] Open
Abstract
Amyotrophic lateral sclerosis (ALS) is a rare adult-onset neurodegenerative disease characterized by progressive motor neuron (MN) loss, muscle denervation and paralysis. Over the past several decades, researchers have made tremendous efforts to understand the pathogenic mechanisms underpinning ALS, with much yet to be resolved. ALS is described as a non-cell autonomous condition with pathology detected in both MNs and non-neuronal cells, such as glial cells and skeletal muscle. Studies in ALS patient and animal models reveal ubiquitous abnormalities in mitochondrial structure and function, and disturbance of intracellular calcium homeostasis in various tissue types, suggesting a pivotal role of aberrant mitochondrial calcium uptake and dysfunctional calcium signalling cascades in ALS pathogenesis. Calcium signalling and mitochondrial dysfunction are intricately related to the manifestation of cell death contributing to MN loss and skeletal muscle dysfunction. In this review, we discuss the potential contribution of intracellular calcium signalling, particularly mitochondrial calcium uptake, in ALS pathogenesis. Functional consequences of excessive mitochondrial calcium uptake and possible therapeutic strategies targeting mitochondrial calcium uptake or the mitochondrial calcium uniporter, the main channel mediating mitochondrial calcium influx, are also discussed.
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Affiliation(s)
- Renjia Zhong
- Department of Applied Physiology and Kinesiology, College of Health and Human Performance, University of Florida, Gainesville, FL, 32611
- Department of Emergency Medicine, the First Affiliated Hospital of China Medical University, Shenyang, Liaoning, China, 110001
| | - Michael T. Rua
- Department of Applied Physiology and Kinesiology, College of Health and Human Performance, University of Florida, Gainesville, FL, 32611
| | - Lan Wei-LaPierre
- Department of Applied Physiology and Kinesiology, College of Health and Human Performance, University of Florida, Gainesville, FL, 32611
- Myology Institute, University of Florida, Gainesville, FL 32611
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6
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Fekete A, Wang LY. Cracking 'the Da Vinci code' of conduct hidden in Ca v 2.1 α1 subunit for presynaptic occupation. J Physiol 2024; 602:539-540. [PMID: 38319956 DOI: 10.1113/jp286116] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2023] [Accepted: 01/25/2024] [Indexed: 02/08/2024] Open
Affiliation(s)
- Adam Fekete
- Program in Neurosciences and Mental Health, SickKids Research Institute, Toronto, Ontario, Canada
- Department of Physiology, University of Toronto, Toronto, Ontario, Canada
| | - Lu-Yang Wang
- Program in Neurosciences and Mental Health, SickKids Research Institute, Toronto, Ontario, Canada
- Department of Physiology, University of Toronto, Toronto, Ontario, Canada
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7
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He K, Han Y, Li X, Hernandez RX, Riboul DV, Feghhi T, Justs KA, Mahneva O, Perry S, Macleod GT, Dickman D. Physiologic and Nanoscale Distinctions Define Glutamatergic Synapses in Tonic vs Phasic Neurons. J Neurosci 2023; 43:4598-4611. [PMID: 37221096 PMCID: PMC10286941 DOI: 10.1523/jneurosci.0046-23.2023] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2023] [Revised: 05/05/2023] [Accepted: 05/11/2023] [Indexed: 05/25/2023] Open
Abstract
Neurons exhibit a striking degree of functional diversity, each one tuned to the needs of the circuitry in which it is embedded. A fundamental functional dichotomy occurs in activity patterns, with some neurons firing at a relatively constant "tonic" rate, while others fire in bursts, a "phasic" pattern. Synapses formed by tonic versus phasic neurons are also functionally differentiated, yet the bases of their distinctive properties remain enigmatic. A major challenge toward illuminating the synaptic differences between tonic and phasic neurons is the difficulty in isolating their physiological properties. At the Drosophila neuromuscular junction, most muscle fibers are coinnervated by two motor neurons: the tonic "MN-Ib" and phasic "MN-Is." Here, we used selective expression of a newly developed botulinum neurotoxin transgene to silence tonic or phasic motor neurons in Drosophila larvae of either sex. This approach highlighted major differences in their neurotransmitter release properties, including probability, short-term plasticity, and vesicle pools. Furthermore, Ca2+ imaging demonstrated ∼2-fold greater Ca2+ influx at phasic neuron release sites relative to tonic, along with an enhanced synaptic vesicle coupling. Finally, confocal and super-resolution imaging revealed that phasic neuron release sites are organized in a more compact arrangement, with enhanced stoichiometry of voltage-gated Ca2+ channels relative to other active zone scaffolds. These data suggest that distinctions in active zone nano-architecture and Ca2+ influx collaborate to differentially tune glutamate release at tonic versus phasic synaptic subtypes.SIGNIFICANCE STATEMENT "Tonic" and "phasic" neuronal subtypes, based on differential firing properties, are common across many nervous systems. Using a recently developed approach to selectively silence transmission from one of these two neurons, we reveal specialized synaptic functional and structural properties that distinguish these specialized neurons. This study provides important insights into how input-specific synaptic diversity is achieved, which could have implications for neurologic disorders that involve changes in synaptic function.
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Affiliation(s)
- Kaikai He
- Department of Neurobiology, University of Southern California, Los Angeles, California 90089
- USC Neuroscience Graduate Program, Los Angeles, California 90089
| | - Yifu Han
- Department of Neurobiology, University of Southern California, Los Angeles, California 90089
- USC Neuroscience Graduate Program, Los Angeles, California 90089
| | - Xiling Li
- Department of Neurobiology, University of Southern California, Los Angeles, California 90089
- USC Neuroscience Graduate Program, Los Angeles, California 90089
| | - Roberto X Hernandez
- Integrative Biology and Neuroscience Graduate Program, Department of Biological Sciences, Florida Atlantic University, Boca Raton, Florida 33431
- International Max Planck Research School for Brain and Behavior, Jupiter, Florida 33458
| | - Danielle V Riboul
- Integrative Biology Graduate Program, Department of Biological Sciences, Florida Atlantic University, Boca Raton, Florida 33431
| | - Touhid Feghhi
- Department of Physics, Florida Atlantic University, Boca Raton, Florida 33431
| | - Karlis A Justs
- Integrative Biology and Neuroscience Graduate Program, Department of Biological Sciences, Florida Atlantic University, Boca Raton, Florida 33431
| | - Olena Mahneva
- Wilkes Honors College, Florida Atlantic University, Jupiter, Florida 33458
| | - Sarah Perry
- Department of Neurobiology, University of Southern California, Los Angeles, California 90089
| | - Gregory T Macleod
- Wilkes Honors College, Florida Atlantic University, Jupiter, Florida 33458
- Institute for Human Health and Disease Intervention, Florida Atlantic University, Jupiter, Florida 33458
| | - Dion Dickman
- Department of Neurobiology, University of Southern California, Los Angeles, California 90089
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Kramer AA, Bennett DF, Barañano KW, Bannister RA. A neurodevelopmental disorder caused by a dysfunctional CACNA1A allele. eNeurologicalSci 2023; 31:100456. [PMID: 36938367 PMCID: PMC10020665 DOI: 10.1016/j.ensci.2023.100456] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2022] [Revised: 11/05/2022] [Accepted: 02/25/2023] [Indexed: 03/06/2023] Open
Abstract
P/Q-type Ca2+ flux into nerve terminals via CaV2.1 channels is essential for neurotransmitter release at neuromuscular junctions and nearly all central synapses. Mutations in CACNA1A, the gene encoding CaV2.1, cause a spectrum of pediatric neurological disorders. We have identified a patient harboring an autosomal-dominant de novo frameshift-causing nucleotide duplication in CACNA1A (c.5018dupG). The duplicated guanine precipitated 43 residues of altered amino acid sequence beginning with a glutamine to serine substitution in CaV2.1 at position 1674 ending with a premature stop codon (CaV2.1 p.Gln1674Serfs*43). The patient presented with episodic downbeat vertical nystagmus, hypotonia, ataxia, developmental delay and febrile seizures. In patch-clamp experiments, no Ba2+ current was observed in tsA-201 cells expressing CaV2.1 p.Gln1674Serfs*43 with β4 and α2δ-1 auxiliary subunits. The ablation of divalent flux in response to depolarization was likely attributable to the inability of CaV2.1 p.Gln1674Serfs*43 to form a complete channel pore. Our results suggest that the pathology resulting from this frameshift-inducing nucleotide duplication is a consequence of an effective haploinsufficiency.
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Affiliation(s)
- Audra A. Kramer
- Department of Pathology, Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, 108 North Greene Street, Baltimore, MD 21201, USA
- Corresponding authors at: National Institutes of Health, Center for Scientific Review, Division of Neuroscience, Development and Aging, 6701 Rockledge Drive, Bethesda, MD 20892, USA.
| | - Daniel F. Bennett
- Department of Pathology, Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, 108 North Greene Street, Baltimore, MD 21201, USA
| | - Kristin W. Barañano
- Department of Neurology, Johns Hopkins University School of Medicine, 200 North Wolfe Street, Suite 2158, Baltimore, MD 21287, USA
| | - Roger A. Bannister
- Department of Pathology, Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, 108 North Greene Street, Baltimore, MD 21201, USA
- Corresponding authors at: National Institutes of Health, Center for Scientific Review, Division of Neuroscience, Development and Aging, 6701 Rockledge Drive, Bethesda, MD 20892, USA.
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9
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Lückemeyer DD, Prudente AS, de Amorim Ferreira M, da Silva AM, Tonello R, Junior SJM, do Prado CSH, de Castro Júnior CJ, Gomez MV, Calixto JB, Ferreira J. Critical Pronociceptive Role of Family 2 Voltage-Gated Calcium Channels in a Novel Mouse Model of HIV-Associated Sensory Neuropathy. Mol Neurobiol 2023; 60:2954-2968. [PMID: 36754911 DOI: 10.1007/s12035-023-03244-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2022] [Accepted: 01/13/2023] [Indexed: 02/10/2023]
Abstract
Some people living with HIV present painful sensory neuropathy (HIV-SN) that is pharmacoresistant, sex-associated, and a major source of morbidity. Since the specific mechanisms underlying HIV-SN are not well understood, the aim of our study was to characterize a novel model of painful HIV-SN by combining the HIV-1 gp120 protein and the antiretroviral stavudine (d4T) in mice and to investigate the pronociceptive role of the family 2 voltage-gated calcium channel (VGCC) α1 subunit (Cav2.X channels) in such a model. HIV-SN was induced in male and female C57BL/6 mice by administration of gp120 and/or d4T and detected by a battery of behavior tests and by immunohistochemistry. The role of Cav2.X channels was assessed by the treatment with selective blockers and agonists as well as by mRNA detection. Repeated administration with gp120 and/or d4T produced long-lasting touch-evoked painful-like behaviors (starting at 6 days, reaching a maximum on day 13, and lasting up to 28 days after treatment started), with a greater intensity in female mice treated with the combination of gp120 + d4T. Moreover, gp120 + d4T treatment reduced the intraepidermal nerve fibers and well-being of female mice, without altering other behaviors. Mechanistically, gp120 + d4T treatment induced Cav2.1, 2.2, and 2.3 transcriptional increases in the dorsal root ganglion and the Cav2.X agonist-induced nociception. Accordingly, intrathecal selective Cav2.2 blockade presented longer and better efficacy in reversing the hyperalgesia induced by gp120 + d4T treatment compared with Cav2.1 or Cav2.3, but also presented the worst safety (inducing side effects at effective doses). We conclude that the family 2 calcium channels (Cav2.X) exert a critical pronociceptive role in a novel mouse model of HIV-SN.
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Affiliation(s)
- Debora Denardin Lückemeyer
- Programa de Pós-Graduação em Farmacologia, Universidade Federal de Santa Catarina, Florianópolis, SC, Brazil
| | - Arthur Silveira Prudente
- Programa de Pós-Graduação em Farmacologia, Universidade Federal de Santa Catarina, Florianópolis, SC, Brazil
| | - Marcella de Amorim Ferreira
- Programa de Pós-Graduação em Farmacologia, Universidade Federal de Santa Catarina, Florianópolis, SC, Brazil
| | - Ana Merian da Silva
- Programa de Pós-Graduação em Farmacologia, Universidade Federal de Santa Catarina, Florianópolis, SC, Brazil
| | - Raquel Tonello
- Department of Anesthesiology, Pain Research Center, University of Cincinnati College of Medicine, Cincinnati, OH, USA
| | - Sérgio José Macedo Junior
- Programa de Pós-Graduação em Farmacologia, Universidade Federal de Santa Catarina, Florianópolis, SC, Brazil
- Centro de Inovação E Ensaios Pré-Clínicos, Florianópolis, SC, Brazil
| | | | | | - Marcus Vinicius Gomez
- Instituto de Educação E Pesquisa da Santa Casa de Belo Horizonte, Belo Horizonte, MG, Brazil
| | | | - Juliano Ferreira
- Programa de Pós-Graduação em Farmacologia, Universidade Federal de Santa Catarina, Florianópolis, SC, Brazil.
- Departamento de Farmacologia, Universidade Federal de Santa Catarina, Florianópolis, SC, Brazil.
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10
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Cunningham KL, Littleton JT. Mechanisms controlling the trafficking, localization, and abundance of presynaptic Ca 2+ channels. Front Mol Neurosci 2023; 15:1116729. [PMID: 36710932 PMCID: PMC9880069 DOI: 10.3389/fnmol.2022.1116729] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2022] [Accepted: 12/26/2022] [Indexed: 01/14/2023] Open
Abstract
Voltage-gated Ca2+ channels (VGCCs) mediate Ca2+ influx to trigger neurotransmitter release at specialized presynaptic sites termed active zones (AZs). The abundance of VGCCs at AZs regulates neurotransmitter release probability (Pr ), a key presynaptic determinant of synaptic strength. Given this functional significance, defining the processes that cooperate to establish AZ VGCC abundance is critical for understanding how these mechanisms set synaptic strength and how they might be regulated to control presynaptic plasticity. VGCC abundance at AZs involves multiple steps, including channel biosynthesis (transcription, translation, and trafficking through the endomembrane system), forward axonal trafficking and delivery to synaptic terminals, incorporation and retention at presynaptic sites, and protein recycling. Here we discuss mechanisms that control VGCC abundance at synapses, highlighting findings from invertebrate and vertebrate models.
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Affiliation(s)
- Karen L. Cunningham
- The Picower Institute for Learning and Memory, Department of Biology, Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA, United States
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11
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Zhang W, Jiang HH, Luo F. Diverse organization of voltage-gated calcium channels at presynaptic active zones. Front Synaptic Neurosci 2022; 14:1023256. [PMID: 36544543 PMCID: PMC9760684 DOI: 10.3389/fnsyn.2022.1023256] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2022] [Accepted: 11/09/2022] [Indexed: 12/12/2022] Open
Abstract
Synapses are highly organized but are also highly diverse in their organization and properties to allow for optimizing the computing power of brain circuits. Along these lines, voltage-gated calcium (CaV) channels at the presynaptic active zone are heterogeneously organized, which creates a variety of calcium dynamics profiles that can shape neurotransmitter release properties of individual synapses. Extensive studies have revealed striking diversity in the subtype, number, and distribution of CaV channels, as well as the nanoscale topographic relationships to docked synaptic vesicles. Further, multi-protein complexes including RIMs, RIM-binding proteins, CAST/ELKS, and neurexins are required for coordinating the diverse organization of CaV channels at the presynaptic active zone. In this review, we highlight major advances in the studies of the functional organization of presynaptic CaV channels and discuss their physiological implications for synaptic transmission and short-term plasticity.
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Affiliation(s)
- Weijia Zhang
- Guangzhou Laboratory, Guangzhou, China,Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, China
| | - He-Hai Jiang
- Guangzhou Laboratory, Guangzhou, China,Bioland Laboratory, Guangzhou, China
| | - Fujun Luo
- Guangzhou Laboratory, Guangzhou, China,Bioland Laboratory, Guangzhou, China,*Correspondence: Fujun Luo
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12
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Pilch KS, Ramgoolam KH, Dolphin AC. Involvement of Ca V 2.2 channels and α 2 δ-1 in homeostatic synaptic plasticity in cultured hippocampal neurons. J Physiol 2022; 600:5333-5351. [PMID: 36377048 PMCID: PMC10107484 DOI: 10.1113/jp283600] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2022] [Accepted: 11/08/2022] [Indexed: 11/16/2022] Open
Abstract
In the mammalian brain, presynaptic CaV 2 channels play a pivotal role in synaptic transmission by mediating fast neurotransmitter exocytosis via influx of Ca2+ into the active zone of presynaptic terminals. However, the distribution and modulation of CaV 2.2 channels at plastic hippocampal synapses remains to be elucidated. Here, we assess CaV 2.2 channels during homeostatic synaptic plasticity, a compensatory form of homeostatic control preventing excessive or insufficient neuronal activity during which extensive active zone remodelling has been described. We show that chronic silencing of neuronal activity in mature hippocampal cultures resulted in elevated presynaptic Ca2+ transients, mediated by increased levels of CaV 2.2 channels at the presynaptic site. This work focused further on the role of α2 δ-1 subunits, important regulators of synaptic transmission and CaV 2.2 channel abundance at the presynaptic membrane. We found that α2 δ-1 overexpression reduces the contribution of CaV 2.2 channels to total Ca2+ flux without altering the amplitude of the Ca2+ transients. Levels of endogenous α2 δ-1 decreased during homeostatic synaptic plasticity, whereas the overexpression of α2 δ-1 prevented homeostatic synaptic plasticity in hippocampal neurons. Together, this study reveals a key role for CaV 2.2 channels and novel roles for α2 δ-1 during synaptic plastic adaptation. KEY POINTS: The roles of CaV 2.2 channels and α2 δ-1 in homeostatic synaptic plasticity in hippocampal neurons in culture were examined. Chronic silencing of neuronal activity resulted in elevated presynaptic Ca2+ transients, mediated by increased levels of CaV 2.2 channels at presynaptic sites. The level of endogenous α2 δ-1 decreased during homeostatic synaptic plasticity, whereas overexpression of α2 δ-1 prevented homeostatic synaptic plasticity in hippocampal neurons. Together, this study reveals a key role for CaV 2.2 channels and novel roles for α2 δ-1 during synaptic plastic adaptation.
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Affiliation(s)
- Kjara S. Pilch
- Department of NeurosciencePhysiology and PharmacologyUniversity College LondonLondonUK
| | - Krishma H. Ramgoolam
- Department of NeurosciencePhysiology and PharmacologyUniversity College LondonLondonUK
| | - Annette C. Dolphin
- Department of NeurosciencePhysiology and PharmacologyUniversity College LondonLondonUK
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13
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Cunningham KL, Sauvola CW, Tavana S, Littleton JT. Regulation of presynaptic Ca 2+ channel abundance at active zones through a balance of delivery and turnover. eLife 2022; 11:78648. [PMID: 35833625 PMCID: PMC9352347 DOI: 10.7554/elife.78648] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2022] [Accepted: 07/13/2022] [Indexed: 12/03/2022] Open
Abstract
Voltage-gated Ca2+ channels (VGCCs) mediate Ca2+ influx to trigger neurotransmitter release at specialized presynaptic sites termed active zones (AZs). The abundance of VGCCs at AZs regulates neurotransmitter release probability (Pr), a key presynaptic determinant of synaptic strength. Although biosynthesis, delivery, and recycling cooperate to establish AZ VGCC abundance, experimentally isolating these distinct regulatory processes has been difficult. Here, we describe how the AZ levels of cacophony (Cac), the sole VGCC-mediating synaptic transmission in Drosophila, are determined. We also analyzed the relationship between Cac, the conserved VGCC regulatory subunit α2δ, and the core AZ scaffold protein Bruchpilot (BRP) in establishing a functional AZ. We find that Cac and BRP are independently regulated at growing AZs, as Cac is dispensable for AZ formation and structural maturation, and BRP abundance is not limiting for Cac accumulation. Additionally, AZs stop accumulating Cac after an initial growth phase, whereas BRP levels continue to increase given extended developmental time. AZ Cac is also buffered against moderate increases or decreases in biosynthesis, whereas BRP lacks this buffering. To probe mechanisms that determine AZ Cac abundance, intravital FRAP and Cac photoconversion were used to separately measure delivery and turnover at individual AZs over a multi-day period. Cac delivery occurs broadly across the AZ population, correlates with AZ size, and is rate-limited by α2δ. Although Cac does not undergo significant lateral transfer between neighboring AZs over the course of development, Cac removal from AZs does occur and is promoted by new Cac delivery, generating a cap on Cac accumulation at mature AZs. Together, these findings reveal how Cac biosynthesis, synaptic delivery, and recycling set the abundance of VGCCs at individual AZs throughout synapse development and maintenance.
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Affiliation(s)
- Karen L Cunningham
- The Picower Institute for Learning and Memory, Massachusetts Institute of Technology, Cambridge, United States
| | - Chad W Sauvola
- The Picower Institute for Learning and Memory, Massachusetts Institute of Technology, Cambridge, United States
| | - Sara Tavana
- The Picower Institute for Learning and Memory, Massachusetts Institute of Technology, Cambridge, United States
| | - J Troy Littleton
- The Picower Institute for Learning and Memory, Massachusetts Institute of Technology, Cambridge, United States
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14
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Glaser T, Shimojo H, Ribeiro DE, Martins PPL, Beco RP, Kosinski M, Sampaio VFA, Corrêa-Velloso J, Oliveira-Giacomelli Á, Lameu C, de Jesus Santos AP, de Souza HDN, Teng YD, Kageyama R, Ulrich H. ATP and spontaneous calcium oscillations control neural stem cell fate determination in Huntington's disease: a novel approach for cell clock research. Mol Psychiatry 2021; 26:2633-2650. [PMID: 32350390 DOI: 10.1038/s41380-020-0717-5] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/30/2019] [Revised: 03/12/2020] [Accepted: 03/24/2020] [Indexed: 12/22/2022]
Abstract
Calcium, the most versatile second messenger, regulates essential biology including crucial cellular events in embryogenesis. We investigated impacts of calcium channels and purinoceptors on neuronal differentiation of normal mouse embryonic stem cells (ESCs), with outcomes being compared to those of in vitro models of Huntington's disease (HD). Intracellular calcium oscillations tracked via real-time fluorescence and luminescence microscopy revealed a significant correlation between calcium transient activity and rhythmic proneuronal transcription factor expression in ESCs stably expressing ASCL-1 or neurogenin-2 promoters fused to luciferase reporter genes. We uncovered that pharmacological manipulation of L-type voltage-gated calcium channels (VGCCs) and purinoceptors induced a two-step process of neuronal differentiation. Specifically, L-type calcium channel-mediated augmentation of spike-like calcium oscillations first promoted stable expression of ASCL-1 in differentiating ESCs, which following P2Y2 purinoceptor activation matured into GABAergic neurons. By contrast, there was neither spike-like calcium oscillations nor responsive P2Y2 receptors in HD-modeling stem cells in vitro. The data shed new light on mechanisms underlying neurogenesis of inhibitory neurons. Moreover, our approach may be tailored to identify pathogenic triggers of other developmental neurological disorders for devising targeted therapies.
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Affiliation(s)
- Talita Glaser
- Department of Biochemistry, Institute of Chemistry, University of Sao Paulo, Sao Paulo, Brazil
| | - Hiromi Shimojo
- Institute for Frontier Life and Medical Sciences, Kyoto University, Kyoto, Japan.,Graduate School of Frontier Biosciences, Osaka University, Suita, Japan
| | - Deidiane Elisa Ribeiro
- Department of Biochemistry, Institute of Chemistry, University of Sao Paulo, Sao Paulo, Brazil
| | | | - Renata Pereira Beco
- Department of Biochemistry, Institute of Chemistry, University of Sao Paulo, Sao Paulo, Brazil
| | - Michal Kosinski
- Departments of Physical Medicine & Rehabilitation and Neurosurgery, Harvard Medical School, Spaulding Rehabilitation Hospital and Brigham and Women's Hospital, Boston, MA, USA.,Translative Plataform for Regenerative Medicine, Mossakowski Medical Research Centre, Polish Academy of Sciences, Warsaw, Poland
| | | | - Juliana Corrêa-Velloso
- Department of Biochemistry, Institute of Chemistry, University of Sao Paulo, Sao Paulo, Brazil
| | | | - Claudiana Lameu
- Department of Biochemistry, Institute of Chemistry, University of Sao Paulo, Sao Paulo, Brazil
| | | | | | - Yang D Teng
- Departments of Physical Medicine & Rehabilitation and Neurosurgery, Harvard Medical School, Spaulding Rehabilitation Hospital and Brigham and Women's Hospital, Boston, MA, USA
| | - Ryoichiro Kageyama
- Institute for Frontier Life and Medical Sciences, Kyoto University, Kyoto, Japan
| | - Henning Ulrich
- Department of Biochemistry, Institute of Chemistry, University of Sao Paulo, Sao Paulo, Brazil.
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15
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Young SM, Veeraraghavan P. Presynaptic voltage-gated calcium channels in the auditory brainstem. Mol Cell Neurosci 2021; 112:103609. [PMID: 33662542 DOI: 10.1016/j.mcn.2021.103609] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2020] [Revised: 02/06/2021] [Accepted: 02/17/2021] [Indexed: 10/22/2022] Open
Abstract
Sound information encoding within the initial synapses in the auditory brainstem requires reliable and precise synaptic transmission in response to rapid and large fluctuations in action potential (AP) firing rates. The magnitude and location of Ca2+ entry through voltage-gated Ca2+ channels (CaV) in the presynaptic terminal are key determinants in triggering AP-mediated release. In the mammalian central nervous system (CNS), the CaV2.1 subtype is the critical subtype for CNS function, since it is the most efficient CaV2 subtype in triggering AP-mediated synaptic vesicle (SV) release. Auditory brainstem synapses utilize CaV2.1 to sustain fast and repetitive SV release to encode sound information. Therefore, understanding the presynaptic mechanisms that control CaV2.1 localization, organization and biophysical properties are integral to understanding auditory processing. Here, we review our current knowledge about the control of presynaptic CaV2 abundance and organization in the auditory brainstem and impact on the regulation of auditory processing.
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Affiliation(s)
- Samuel M Young
- Department of Anatomy and Cell Biology, University of Iowa Carver College of Medicine, Iowa City, IA 52242, USA; Department of Otolaryngology, University of Iowa Carver College of Medicine, Iowa City, IA 52242, USA; Iowa Neuroscience Institute, University of Iowa Carver College of Medicine, Iowa City, IA 52242, USA.
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16
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Primary and secondary motoneurons use different calcium channel types to control escape and swimming behaviors in zebrafish. Proc Natl Acad Sci U S A 2020; 117:26429-26437. [PMID: 33020266 DOI: 10.1073/pnas.2015866117] [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: 12/24/2022] Open
Abstract
The escape response and rhythmic swimming in zebrafish are distinct behaviors mediated by two functionally distinct motoneuron (Mn) types. The primary (1°Mn) type depresses and has a large quantal content (Qc) and a high release probability (Pr). Conversely, the secondary (2°Mn) type facilitates and has low and variable Qc and Pr. This functional duality matches well the distinct associated behaviors, with the 1°Mn providing the strong, singular C bend initiating escape and the 2°Mn conferring weaker, rhythmic contractions. Contributing to these functional distinctions is our identification of P/Q-type calcium channels mediating transmitter release in 1°Mns and N-type channels in 2°Mns. Remarkably, despite these functional and behavioral distinctions, all ∼15 individual synapses on each muscle cell are shared by a 1°Mn bouton and at least one 2°Mn bouton. This blueprint of synaptic sharing provides an efficient way of controlling two different behaviors at the level of a single postsynaptic cell.
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17
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Meyer JO, Dahimene S, Page KM, Ferron L, Kadurin I, Ellaway JIJ, Zhao P, Patel T, Rothwell SW, Lin P, Pratt WS, Dolphin AC. Disruption of the Key Ca 2+ Binding Site in the Selectivity Filter of Neuronal Voltage-Gated Calcium Channels Inhibits Channel Trafficking. Cell Rep 2020; 29:22-33.e5. [PMID: 31577951 PMCID: PMC6899504 DOI: 10.1016/j.celrep.2019.08.079] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2018] [Revised: 06/20/2019] [Accepted: 08/22/2019] [Indexed: 12/05/2022] Open
Abstract
Voltage-gated calcium channels are exquisitely Ca2+ selective, conferred primarily by four conserved pore-loop glutamate residues contributing to the selectivity filter. There has been little previous work directly measuring whether the trafficking of calcium channels requires their ability to bind Ca2+ in the selectivity filter or to conduct Ca2+. Here, we examine trafficking of neuronal CaV2.1 and 2.2 channels with mutations in their selectivity filter and find reduced trafficking to the cell surface in cell lines. Furthermore, in hippocampal neurons, there is reduced trafficking to the somatic plasma membrane, into neurites, and to presynaptic terminals. However, the CaV2.2 selectivity filter mutants are still influenced by auxiliary α2δ subunits and, albeit to a reduced extent, by β subunits, indicating the channels are not grossly misfolded. Our results indicate that Ca2+ binding in the pore of CaV2 channels may promote their correct trafficking, in combination with auxiliary subunits. Furthermore, physiological studies utilizing selectivity filter mutant CaV channels should be interpreted with caution. Selectivity filter mutations in CaV2 channels block inward Ba2+ currents Surprisingly, these mutations severely reduce trafficking of the CaV2 channels Pore mutant N-type channels show reduced expression in presynaptic terminals Pore mutant channels still require β and α2δ and thus are not grossly misfolded
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Affiliation(s)
- James O Meyer
- Department of Neuroscience, Physiology and Pharmacology, University College London, London WC1E 6BT, UK
| | - Shehrazade Dahimene
- Department of Neuroscience, Physiology and Pharmacology, University College London, London WC1E 6BT, UK
| | - Karen M Page
- Department of Neuroscience, Physiology and Pharmacology, University College London, London WC1E 6BT, UK
| | - Laurent Ferron
- Department of Neuroscience, Physiology and Pharmacology, University College London, London WC1E 6BT, UK
| | - Ivan Kadurin
- Department of Neuroscience, Physiology and Pharmacology, University College London, London WC1E 6BT, UK
| | - Joseph I J Ellaway
- Department of Neuroscience, Physiology and Pharmacology, University College London, London WC1E 6BT, UK
| | - Pengxiang Zhao
- Department of Neuroscience, Physiology and Pharmacology, University College London, London WC1E 6BT, UK
| | - Tarun Patel
- Department of Neuroscience, Physiology and Pharmacology, University College London, London WC1E 6BT, UK
| | - Simon W Rothwell
- Department of Neuroscience, Physiology and Pharmacology, University College London, London WC1E 6BT, UK
| | - Peipeng Lin
- Department of Neuroscience, Physiology and Pharmacology, University College London, London WC1E 6BT, UK
| | - Wendy S Pratt
- Department of Neuroscience, Physiology and Pharmacology, University College London, London WC1E 6BT, UK
| | - Annette C Dolphin
- Department of Neuroscience, Physiology and Pharmacology, University College London, London WC1E 6BT, UK.
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18
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Bikbaev A, Ciuraszkiewicz-Wojciech A, Heck J, Klatt O, Freund R, Mitlöhner J, Enrile Lacalle S, Sun M, Repetto D, Frischknecht R, Ablinger C, Rohlmann A, Missler M, Obermair GJ, Di Biase V, Heine M. Auxiliary α2δ1 and α2δ3 Subunits of Calcium Channels Drive Excitatory and Inhibitory Neuronal Network Development. J Neurosci 2020; 40:4824-4841. [PMID: 32414783 PMCID: PMC7326358 DOI: 10.1523/jneurosci.1707-19.2020] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2019] [Revised: 03/31/2020] [Accepted: 05/09/2020] [Indexed: 01/21/2023] Open
Abstract
VGCCs are multisubunit complexes that play a crucial role in neuronal signaling. Auxiliary α2δ subunits of VGCCs modulate trafficking and biophysical properties of the pore-forming α1 subunit and trigger excitatory synaptogenesis. Alterations in the expression level of α2δ subunits were implicated in several syndromes and diseases, including chronic neuropathic pain, autism, and epilepsy. However, the contribution of distinct α2δ subunits to excitatory/inhibitory imbalance and aberrant network connectivity characteristic for these pathologic conditions remains unclear. Here, we show that α2δ1 overexpression enhances spontaneous neuronal network activity in developing and mature cultures of hippocampal neurons. In contrast, overexpression, but not downregulation, of α2δ3 enhances neuronal firing in immature cultures, whereas later in development it suppresses neuronal activity. We found that α2δ1 overexpression increases excitatory synaptic density and selectively enhances presynaptic glutamate release, which is impaired on α2δ1 knockdown. Overexpression of α2δ3 increases the excitatory synaptic density as well but also facilitates spontaneous GABA release and triggers an increase in the density of inhibitory synapses, which is accompanied by enhanced axonaloutgrowth in immature interneurons. Together, our findings demonstrate that α2δ1 and α2δ3 subunits play distinct but complementary roles in driving formation of structural and functional network connectivity during early development. An alteration in α2δ surface expression during critical developmental windows can therefore play a causal role and have a profound impact on the excitatory-to-inhibitory balance and network connectivity.SIGNIFICANCE STATEMENT The computational capacity of neuronal networks is determined by their connectivity. Chemical synapses are the main interface for transfer of information between individual neurons. The initial formation of network connectivity requires spontaneous electrical activity and the calcium channel-mediated signaling. We found that, in early development, auxiliary α2δ3 subunits of calcium channels foster presynaptic release of GABA, trigger formation of inhibitory synapses, and promote axonal outgrowth in inhibitory interneurons. In contrast, later in development, α2δ1 subunits promote the glutamatergic neurotransmission and synaptogenesis, as well as strongly enhance neuronal network activity. We propose that formation of connectivity in neuronal networks is associated with a concerted interplay of α2δ1 and α2δ3 subunits of calcium channels.
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Affiliation(s)
- Arthur Bikbaev
- RG Functional Neurobiology, Institute for Developmental Biology and Neurobiology, Johannes Gutenberg University Mainz, Mainz, 55128, Germany
| | - Anna Ciuraszkiewicz-Wojciech
- RG Molecular Physiology, Leibniz Institute for Neurobiology, Magdeburg, 39118, Germany
- Center for Behavioral Brain Sciences, Otto-von-Guericke University Magdeburg, Magdeburg, 39106, Germany
| | - Jennifer Heck
- RG Functional Neurobiology, Institute for Developmental Biology and Neurobiology, Johannes Gutenberg University Mainz, Mainz, 55128, Germany
| | - Oliver Klatt
- Institute for Anatomy and Molecular Neurobiology, University of Münster, Münster, 48149, Germany
| | - Romy Freund
- RG Molecular Physiology, Leibniz Institute for Neurobiology, Magdeburg, 39118, Germany
| | - Jessica Mitlöhner
- RG Brain Extracellular Matrix, Leibniz Institute for Neurobiology, Magdeburg, 39118, Germany
| | - Sara Enrile Lacalle
- RG Molecular Physiology, Leibniz Institute for Neurobiology, Magdeburg, 39118, Germany
| | - Miao Sun
- Institute for Anatomy and Molecular Neurobiology, University of Münster, Münster, 48149, Germany
| | - Daniele Repetto
- Institute for Anatomy and Molecular Neurobiology, University of Münster, Münster, 48149, Germany
| | - Renato Frischknecht
- RG Brain Extracellular Matrix, Leibniz Institute for Neurobiology, Magdeburg, 39118, Germany
- Department of Biology, Animal Physiology, Friedrich Alexander University of Erlangen-Nuremberg, Erlangen, 91058, Germany
| | - Cornelia Ablinger
- Institute of Physiology, Medical University Innsbruck, Innsbruck, 6020, Austria
| | - Astrid Rohlmann
- Institute for Anatomy and Molecular Neurobiology, University of Münster, Münster, 48149, Germany
| | - Markus Missler
- Institute for Anatomy and Molecular Neurobiology, University of Münster, Münster, 48149, Germany
| | - Gerald J Obermair
- Division Physiology, Karl Landsteiner University of Health Sciences, Krems, 3500, Austria
| | - Valentina Di Biase
- Institute of Molecular and Clinical Pharmacology, Medical University Innsbruck, Innsbruck, 6020, Austria
| | - Martin Heine
- RG Functional Neurobiology, Institute for Developmental Biology and Neurobiology, Johannes Gutenberg University Mainz, Mainz, 55128, Germany
- Center for Behavioral Brain Sciences, Otto-von-Guericke University Magdeburg, Magdeburg, 39106, Germany
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19
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Wang S, Cortes CJ. Interactions with PDZ proteins diversify voltage-gated calcium channel signaling. J Neurosci Res 2020; 99:332-348. [PMID: 32476168 DOI: 10.1002/jnr.24650] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2020] [Revised: 04/29/2020] [Accepted: 05/07/2020] [Indexed: 11/12/2022]
Abstract
Voltage-gated Ca2+ (CaV ) channels are crucial for neuronal excitability and synaptic transmission upon depolarization. Their properties in vivo are modulated by their interaction with a variety of scaffolding proteins. Such interactions can influence the function and localization of CaV channels, as well as their coupling to intracellular second messengers and regulatory pathways, thus amplifying their signaling potential. Among these scaffolding proteins, a subset of PDZ (postsynaptic density-95, Drosophila discs-large, and zona occludens)-domain containing proteins play diverse roles in modulating CaV channel properties. At the presynaptic terminal, PDZ proteins enrich CaV channels in the active zone, enabling neurotransmitter release by maintaining a tight and vital link between channels and vesicles. In the postsynaptic density, these interactions are essential in regulating dendritic spine morphology and postsynaptic signaling cascades. In this review, we highlight the studies that demonstrate dynamic regulations of neuronal CaV channels by PDZ proteins. We discuss the role of PDZ proteins in controlling channel activity, regulating channel cell surface density, and influencing channel-mediated downstream signaling events. We highlight the importance of PDZ protein regulations of CaV channels and evaluate the link between this regulatory effect and human disease.
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Affiliation(s)
- Shiyi Wang
- Department of Cell Biology, Duke University, Durham, NC, USA.,Department of Neurology, Duke University, Durham, NC, USA
| | - Constanza J Cortes
- Department of Neurology, Duke University, Durham, NC, USA.,Department of Cell, Developmental and Integrative Biology, University of Alabama Birmingham, Birmingham, AL, USA
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20
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Tyagi S, Ribera AB, Bannister RA. Zebrafish as a Model System for the Study of Severe Ca V2.1 (α 1A) Channelopathies. Front Mol Neurosci 2020; 12:329. [PMID: 32116539 PMCID: PMC7018710 DOI: 10.3389/fnmol.2019.00329] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2019] [Accepted: 12/23/2019] [Indexed: 02/02/2023] Open
Abstract
The P/Q-type CaV2.1 channel regulates neurotransmitter release at neuromuscular junctions (NMJ) and many central synapses. CACNA1A encodes the pore-containing α1A subunit of CaV2.1 channels. In humans, de novo CACNA1A mutations result in a wide spectrum of neurological, neuromuscular, and movement disorders, such as familial hemiplegic migraine type 1 (FHM1), episodic ataxia type 2 (EA2), as well as a more recently discovered class of more severe disorders, which are characterized by ataxia, hypotonia, cerebellar atrophy, and cognitive/developmental delay. Heterologous expression of CaV2.1 channels has allowed for an understanding of the consequences of CACNA1A missense mutations on channel function. In contrast, a mechanistic understanding of how specific CACNA1A mutations lead in vivo to the resultant phenotypes is lacking. In this review, we present the zebrafish as a model to both study in vivo mechanisms of CACNA1A mutations that result in synaptic and behavioral defects and to screen for effective drug therapies to combat these and other CaV2.1 channelopathies.
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Affiliation(s)
- Sidharth Tyagi
- Medical Scientist Training Program, Yale University School of Medicine, New Haven, CT, United States
| | - Angeles B Ribera
- Department of Physiology and Biophysics, University of Colorado School of Medicine, Aurora, CO, United States
| | - Roger A Bannister
- Department of Pathology, University of Maryland School of Medicine, Baltimore, MD, United States.,Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, Baltimore, MD, United States
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21
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Ferron L, Novazzi CG, Pilch KS, Moreno C, Ramgoolam K, Dolphin AC. FMRP regulates presynaptic localization of neuronal voltage gated calcium channels. Neurobiol Dis 2020; 138:104779. [PMID: 31991246 PMCID: PMC7152798 DOI: 10.1016/j.nbd.2020.104779] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2019] [Revised: 01/09/2020] [Accepted: 01/24/2020] [Indexed: 12/31/2022] Open
Abstract
Fragile X syndrome (FXS), the most common form of inherited intellectual disability and autism, results from the loss of fragile X mental retardation protein (FMRP). We have recently identified a direct interaction of FMRP with voltage-gated Ca2+ channels that modulates neurotransmitter release. In the present study we used a combination of optophysiological tools to investigate the impact of FMRP on the targeting of voltage-gated Ca2+ channels to the active zones in neuronal presynaptic terminals. We monitored Ca2+ transients at synaptic boutons of dorsal root ganglion (DRG) neurons using the genetically-encoded Ca2+ indicator GCaMP6f tagged to synaptophysin. We show that knock-down of FMRP induces an increase of the amplitude of the Ca2+ transient in functionally-releasing presynaptic terminals, and that this effect is due to an increase of N-type Ca2+ channel contribution to the total Ca2+ transient. Dynamic regulation of CaV2.2 channel trafficking is key to the function of these channels in neurons. Using a CaV2.2 construct with an α-bungarotoxin binding site tag, we further investigate the impact of FMRP on the trafficking of CaV2.2 channels. We show that forward trafficking of CaV2.2 channels from the endoplasmic reticulum to the plasma membrane is reduced when co-expressed with FMRP. Altogether our data reveal a critical role of FMRP on localization of CaV channels to the presynaptic terminals and how its defect in a context of FXS can profoundly affect synaptic transmission. Loss of FMRP increases presynaptic Ca2+ transients. FMRP is a negative regulator of presynaptic Cav2.2 channel abundance. FMRP reduces the forward trafficking of Cav2.2 channels from ER to plasma membrane. Distal part of FMRP carboxy terminus is key for interaction with Cav2.2 channels.
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Affiliation(s)
- Laurent Ferron
- Department of Neuroscience, Physiology and Pharmacology, University College London, London WC1E 6BT, UK.
| | - Cesare G Novazzi
- Department of Neuroscience, Physiology and Pharmacology, University College London, London WC1E 6BT, UK
| | - Kjara S Pilch
- Department of Neuroscience, Physiology and Pharmacology, University College London, London WC1E 6BT, UK
| | - Cristian Moreno
- Department of Neuroscience, Physiology and Pharmacology, University College London, London WC1E 6BT, UK
| | - Krishma Ramgoolam
- Department of Neuroscience, Physiology and Pharmacology, University College London, London WC1E 6BT, UK
| | - Annette C Dolphin
- Department of Neuroscience, Physiology and Pharmacology, University College London, London WC1E 6BT, UK
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22
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Huang YC, Pirri JK, Rayes D, Gao S, Mulcahy B, Grant J, Saheki Y, Francis MM, Zhen M, Alkema MJ. Gain-of-function mutations in the UNC-2/CaV2α channel lead to excitation-dominant synaptic transmission in Caenorhabditis elegans. eLife 2019; 8:e45905. [PMID: 31364988 PMCID: PMC6713474 DOI: 10.7554/elife.45905] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2019] [Accepted: 07/30/2019] [Indexed: 01/17/2023] Open
Abstract
Mutations in pre-synaptic voltage-gated calcium channels can lead to familial hemiplegic migraine type 1 (FHM1). While mammalian studies indicate that the migraine brain is hyperexcitable due to enhanced excitation or reduced inhibition, the molecular and cellular mechanisms underlying this excitatory/inhibitory (E/I) imbalance are poorly understood. We identified a gain-of-function (gf) mutation in the Caenorhabditis elegans CaV2 channel α1 subunit, UNC-2, which leads to increased calcium currents. unc-2(zf35gf) mutants exhibit hyperactivity and seizure-like motor behaviors. Expression of the unc-2 gene with FHM1 substitutions R192Q and S218L leads to hyperactivity similar to that of unc-2(zf35gf) mutants. unc-2(zf35gf) mutants display increased cholinergic and decreased GABAergic transmission. Moreover, increased cholinergic transmission in unc-2(zf35gf) mutants leads to an increase of cholinergic synapses and a TAX-6/calcineurin-dependent reduction of GABA synapses. Our studies reveal mechanisms through which CaV2 gain-of-function mutations disrupt excitation-inhibition balance in the nervous system.
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Affiliation(s)
- Yung-Chi Huang
- Department of NeurobiologyUniversity of Massachusetts Medical SchoolWorcesterUnited States
| | - Jennifer K Pirri
- Department of NeurobiologyUniversity of Massachusetts Medical SchoolWorcesterUnited States
| | - Diego Rayes
- Department of NeurobiologyUniversity of Massachusetts Medical SchoolWorcesterUnited States
| | - Shangbang Gao
- Lunenfeld-Tanenbaum Research InstituteMount Sinai HospitalTorontoCanada
| | - Ben Mulcahy
- Lunenfeld-Tanenbaum Research InstituteMount Sinai HospitalTorontoCanada
| | - Jeff Grant
- Department of NeurobiologyUniversity of Massachusetts Medical SchoolWorcesterUnited States
| | - Yasunori Saheki
- Lulu and Anthony Wang Laboratory of Neural Circuits and BehaviorThe Rockefeller UniversityNew YorkUnited States
| | - Michael M Francis
- Department of NeurobiologyUniversity of Massachusetts Medical SchoolWorcesterUnited States
| | - Mei Zhen
- Lunenfeld-Tanenbaum Research InstituteMount Sinai HospitalTorontoCanada
- Department of Molecular GeneticsUniversity of TorontoTorontoCanada
- Department of PhysiologyUniversity of TorontoTorontoCanada
| | - Mark J Alkema
- Department of NeurobiologyUniversity of Massachusetts Medical SchoolWorcesterUnited States
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23
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Burke KJ, Bender KJ. Modulation of Ion Channels in the Axon: Mechanisms and Function. Front Cell Neurosci 2019; 13:221. [PMID: 31156397 PMCID: PMC6533529 DOI: 10.3389/fncel.2019.00221] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2019] [Accepted: 05/01/2019] [Indexed: 12/11/2022] Open
Abstract
The axon is responsible for integrating synaptic signals, generating action potentials (APs), propagating those APs to downstream synapses and converting them into patterns of neurotransmitter vesicle release. This process is mediated by a rich assortment of voltage-gated ion channels whose function can be affected on short and long time scales by activity. Moreover, neuromodulators control the activity of these proteins through G-protein coupled receptor signaling cascades. Here, we review cellular mechanisms and signaling pathways involved in axonal ion channel modulation and examine how changes to ion channel function affect AP initiation, AP propagation, and the release of neurotransmitter. We then examine how these mechanisms could modulate synaptic function by focusing on three key features of synaptic information transmission: synaptic strength, synaptic variability, and short-term plasticity. Viewing these cellular mechanisms of neuromodulation from a functional perspective may assist in extending these findings to theories of neural circuit function and its neuromodulation.
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Affiliation(s)
| | - Kevin J. Bender
- Neuroscience Graduate Program and Department of Neurology, Kavli Institute for Fundamental Neuroscience, Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, CA, United States
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24
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Heck J, Parutto P, Ciuraszkiewicz A, Bikbaev A, Freund R, Mitlöhner J, Andres-Alonso M, Fejtova A, Holcman D, Heine M. Transient Confinement of Ca V2.1 Ca 2+-Channel Splice Variants Shapes Synaptic Short-Term Plasticity. Neuron 2019; 103:66-79.e12. [PMID: 31104951 DOI: 10.1016/j.neuron.2019.04.030] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2018] [Revised: 01/12/2019] [Accepted: 04/18/2019] [Indexed: 02/07/2023]
Abstract
The precision and reliability of synaptic information transfer depend on the molecular organization of voltage-gated calcium channels (VGCCs) within the presynaptic membrane. Alternative splicing of exon 47 affects the C-terminal structure of VGCCs and their affinity to intracellular partners and synaptic vesicles (SVs). We show that hippocampal synapses expressing VGCCs either with exon 47 (CaV2.1+47) or without (CaV2.1Δ47) differ in release probability and short-term plasticity. Tracking single channels revealed transient visits (∼100 ms) of presynaptic VGCCs in nanodomains (∼80 nm) that were controlled by neuronal network activity. Surprisingly, despite harboring prominent binding sites to scaffold proteins, CaV2.1+47 persistently displayed higher mobility within nanodomains. Synaptic accumulation of CaV2.1 was accomplished by optogenetic clustering, but only CaV2.1+47 increased transmitter release and enhanced synaptic short-term depression. We propose that exon 47-related alternative splicing of CaV2.1 channels controls synapse-specific release properties at the level of channel mobility-dependent coupling between VGCCs and SVs.
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Affiliation(s)
- Jennifer Heck
- Research Group Molecular Physiology, Leibniz-Institute for Neurobiology, Brenneckestr. 6, 39118 Magdeburg, Germany; Research Group Functional Neurobiology at the Institute of Developmental Biology and Neurobiology, Johannes Gutenberg University Mainz, Mainz, Germany
| | - Pierre Parutto
- Group of Applied Mathematics and Computational Biology, IBENS, Ecole Normale Superieure, Paris, France
| | - Anna Ciuraszkiewicz
- Research Group Molecular Physiology, Leibniz-Institute for Neurobiology, Brenneckestr. 6, 39118 Magdeburg, Germany; Center for Behavioral Brain Sciences (CBBS), Otto-von-Guericke-University Magdeburg, 39106 Magdeburg, Germany
| | - Arthur Bikbaev
- Research Group Molecular Physiology, Leibniz-Institute for Neurobiology, Brenneckestr. 6, 39118 Magdeburg, Germany; Research Group Functional Neurobiology at the Institute of Developmental Biology and Neurobiology, Johannes Gutenberg University Mainz, Mainz, Germany
| | - Romy Freund
- Research Group Molecular Physiology, Leibniz-Institute for Neurobiology, Brenneckestr. 6, 39118 Magdeburg, Germany
| | - Jessica Mitlöhner
- Department of Neurochemistry and Molecular Biology, Leibniz-Institute for Neurobiology, Brenneckestr. 6, 39118 Magdeburg, Germany
| | - Maria Andres-Alonso
- Research Group Presynaptic Plasticity, Leibniz-Institute for Neurobiology, Brenneckestr. 6, 39118 Magdeburg, Germany
| | - Anna Fejtova
- Center for Behavioral Brain Sciences (CBBS), Otto-von-Guericke-University Magdeburg, 39106 Magdeburg, Germany; Research Group Presynaptic Plasticity, Leibniz-Institute for Neurobiology, Brenneckestr. 6, 39118 Magdeburg, Germany; Department of Psychiatry and Psychotherapy, University Hospital, Friedrich-Alexander-University Erlangen-Nuremberg, Erlangen, Germany
| | - David Holcman
- Group of Applied Mathematics and Computational Biology, IBENS, Ecole Normale Superieure, Paris, France; Churchill College, University of Cambridge, Cambridge CB3 0DS, UK.
| | - Martin Heine
- Research Group Molecular Physiology, Leibniz-Institute for Neurobiology, Brenneckestr. 6, 39118 Magdeburg, Germany; Center for Behavioral Brain Sciences (CBBS), Otto-von-Guericke-University Magdeburg, 39106 Magdeburg, Germany; Research Group Functional Neurobiology at the Institute of Developmental Biology and Neurobiology, Johannes Gutenberg University Mainz, Mainz, Germany.
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25
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Guzman GA, Guzman RE, Jordan N, Hidalgo P. A Tripartite Interaction Among the Calcium Channel α 1- and β-Subunits and F-Actin Increases the Readily Releasable Pool of Vesicles and Its Recovery After Depletion. Front Cell Neurosci 2019; 13:125. [PMID: 31130843 PMCID: PMC6509170 DOI: 10.3389/fncel.2019.00125] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2018] [Accepted: 03/13/2019] [Indexed: 11/13/2022] Open
Abstract
Neurotransmitter release is initiated by the influx of Ca2+via voltage-gated calcium channels. The accessory β-subunit (CaVβ) of these channels shapes synaptic transmission by associating with the pore-forming subunit (CaVα1) and up-regulating presynaptic calcium currents. Besides CaVα1, CaVβ interacts with several partners including actin filaments (F-actin). These filaments are known to associate with synaptic vesicles (SVs) at the presynaptic terminals and support their translocation within different pools, but the role of CaVβ/F-actin association on synaptic transmission has not yet been explored. We here study how CaVβ4, the major calcium channel β isoform in mamalian brain, modifies synaptic transmission in concert with F-actin in cultured hippocampal neurons. We analyzed the effect of exogenous CaVβ4 before and after pharmacological disruption of the actin cytoskeleton and dissected calcium channel-dependent and -independent functions by comparing the effects of the wild-type subunit with the one bearing a double mutation that impairs binding to CaVα1. We found that exogenously expressed wild-type CaVβ4 enhances spontaneous and depolarization-evoked excitatory postsynaptic currents (EPSCs) without altering synaptogenesis. CaVβ4 increases the size of the readily releasable pool (RRP) of SVs at resting conditions and accelerates their recovery after depletion. The enhanced neurotransmitter release induced by CaVβ4 is abolished upon disruption of the actin cytoskeleton. The CaVα1 association-deficient CaVβ4 mutant associates with actin filaments, but neither alters postsynaptic responses nor the time course of the RRP recovery. Furthermore, this mutant protein preserves the ability to increase the RRP size. These results indicate that the interplay between CaVβ4 and F-actin also support the recruitment of SVs to the RRP in a CaVα1-independent manner. Our studies show an emerging role of CaVβ in determining SV maturation toward the priming state and its replenishment after release. We envision that this subunit plays a role in coupling exocytosis to endocytosis during the vesicle cycle.
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Affiliation(s)
- Gustavo A Guzman
- Institute of Complex Systems 4, Zelluläre Biophysik, Forschungszentrum Jülich, Jülich, Germany
| | - Raul E Guzman
- Institute of Complex Systems 4, Zelluläre Biophysik, Forschungszentrum Jülich, Jülich, Germany
| | - Nadine Jordan
- Institute of Complex Systems 4, Zelluläre Biophysik, Forschungszentrum Jülich, Jülich, Germany
| | - Patricia Hidalgo
- Institute of Complex Systems 4, Zelluläre Biophysik, Forschungszentrum Jülich, Jülich, Germany.,Institute of Biochemistry, Heinrich-Heine University, Düsseldorf, Germany
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26
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Tyagi S, Bendrick TR, Filipova D, Papadopoulos S, Bannister RA. A mutation in Ca V2.1 linked to a severe neurodevelopmental disorder impairs channel gating. J Gen Physiol 2019; 151:850-859. [PMID: 31015257 PMCID: PMC6571999 DOI: 10.1085/jgp.201812237] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2018] [Revised: 02/04/2019] [Accepted: 03/18/2019] [Indexed: 01/07/2023] Open
Abstract
Ca2+ flux into axon terminals via P-/Q-type CaV2.1 channels is the trigger for neurotransmitter vesicle release at neuromuscular junctions (NMJs) and many central synapses. Recently, an arginine to proline substitution (R1673P) in the S4 voltage-sensing helix of the fourth membrane-bound repeat of CaV2.1 was linked to a severe neurological disorder characterized by generalized hypotonia, ataxia, cerebellar atrophy, and global developmental delay. The R1673P mutation was proposed to cause a gain of function in CaV2.1 leading to neuronal Ca2+ toxicity based on the ability of the mutant channel to rescue the photoreceptor response in CaV2.1-deficient Drosophila cacophony larvae. Here, we show that the corresponding mutation in rat CaV2.1 (R1624P) causes a profound loss of channel function; voltage-clamp analysis of tsA-201 cells expressing this mutant channel revealed an ∼25-mV depolarizing shift in the voltage dependence of activation. This alteration in activation implies that a significant fraction of CaV2.1 channels resident in presynaptic terminals are unlikely to open in response to an action potential, thereby increasing the probability of synaptic failure at both NMJs and central synapses. Indeed, the mutant channel supported only minimal Ca2+ flux in response to an action potential-like waveform. Application of GV-58, a compound previously shown to stabilize the open state of wild-type CaV2.1 channels, partially restored Ca2+ current by shifting mutant activation to more hyperpolarizing potentials and slowing deactivation. Consequently, GV-58 also rescued a portion of Ca2+ flux during action potential-like stimuli. Thus, our data raise the possibility that therapeutic agents that increase channel open probability or prolong action potential duration may be effective in combatting this and other severe neurodevelopmental disorders caused by loss-of-function mutations in CaV2.1.
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Affiliation(s)
- Sidharth Tyagi
- Department of Medicine-Cardiology Division, University of Colorado School of Medicine, Aurora, CO
| | - Tyler R Bendrick
- Department of Medicine-Cardiology Division, University of Colorado School of Medicine, Aurora, CO
| | - Dilyana Filipova
- Department of Vegetative Physiology, University of Cologne, Cologne, Germany
| | - Symeon Papadopoulos
- Department of Vegetative Physiology, University of Cologne, Cologne, Germany
| | - Roger A Bannister
- Department of Medicine-Cardiology Division, University of Colorado School of Medicine, Aurora, CO
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27
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Brockhaus J, Brüggen B, Missler M. Imaging and Analysis of Presynaptic Calcium Influx in Cultured Neurons Using synGCaMP6f. Front Synaptic Neurosci 2019; 11:12. [PMID: 31057389 PMCID: PMC6477507 DOI: 10.3389/fnsyn.2019.00012] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2018] [Accepted: 03/26/2019] [Indexed: 12/12/2022] Open
Abstract
Presynaptic Ca2+ influx through voltage-gated calcium channels (VGCCs) is a key step in synaptic transmission that links action potential (AP)-derived depolarization to vesicle release. However, investigation of presynaptic Ca2+ influx by patch clamp recordings is difficult due to the small size of the majority of synaptic boutons along thin axons that hamper clamp control. Genetically encoded calcium indicators (GECIs) in combination with live cell imaging provide an alternative method to study Ca2+ transients in individual presynaptic terminals. The indicator GCaMP6f was developed for fast speed and high sensitivity in detecting Ca2+ transients even in subcellular compartments. We fused GCaMP6f to synaptophysin (synGCaMP6f) to enrich the calcium indicator in presynaptic boutons of transfected primary hippocampal neurons to study presynaptic Ca2+ changes in response to individual APs or short bursts. Changes in fluorescence intensity were evaluated by normalization to control level or, alternatively, by normalization to maximal fluorescence using the calcium ionophore ionomycin. Measurements revealed robust Ca2+ transients with amplitudes that depend on parameters like the number of APs, stimulation frequency or external calcium concentration. Our findings indicate an appropriate sensitivity of synGCaMP6f for studying total presynaptic Ca2+ transients induced by single APs or short bursts that showed little rundown of the response after repeated bursts. Moreover, these recordings are fast enough to even study short-term plasticity like paired pulse facilitation (PPF) and frequency dependence of Ca2+ transients. In addition, synGCaMP6f could be used to dissect the contribution of different subtypes of VGCCs to presynaptic Ca2+ influx. Our results demonstrate that synGCaMP6f allows the reliable analysis of changes in presynaptic calcium concentration at many individual synaptic boutons in parallel and provides the possibility to study the regulation of this important step in synaptic transmission.
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Affiliation(s)
- Johannes Brockhaus
- Institute of Anatomy and Molecular Neurobiology, Westfälische Wilhelms-University, Münster, Germany
| | - Bianca Brüggen
- Institute of Anatomy and Molecular Neurobiology, Westfälische Wilhelms-University, Münster, Germany
| | - Markus Missler
- Institute of Anatomy and Molecular Neurobiology, Westfälische Wilhelms-University, Münster, Germany
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28
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Heine M, Heck J, Ciuraszkiewicz A, Bikbaev A. Dynamic compartmentalization of calcium channel signalling in neurons. Neuropharmacology 2019; 169:107556. [PMID: 30851307 DOI: 10.1016/j.neuropharm.2019.02.038] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2018] [Revised: 02/16/2019] [Accepted: 02/27/2019] [Indexed: 12/13/2022]
Abstract
Calcium fluxes through the neuronal membrane are strictly limited in time due to biophysical properties of voltage-gated and ligand-activated ion channels and receptors. Being embedded into the crowded dynamic environment of biological membranes, Ca2+-permeable receptors and channels undergo perpetual spatial rearrangement, which enables their temporary association and formation of transient signalling complexes. Thus, efficient calcium-mediated signal transduction requires mechanisms to support very precise spatiotemporal alignment of the calcium source and Ca2+-binding lipids and proteins in a highly dynamic environment. The mobility of calcium channels and calcium-sensing proteins themselves can be considered as a physiologically meaningful variable that affects calcium-mediated signalling in neurons. In this review, we will focus on voltage-gated calcium channels (VGCCs) and activity-induced relocation of stromal interaction molecules (STIMs) in the endoplasmic reticulum (ER) to show that particularly in time ranges between milliseconds to minutes, dynamic rearrangement of calcium conducting channels and sensor molecules is of physiological relevance. This article is part of the special issue entitled 'Mobility and trafficking of neuronal membrane proteins'.
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Affiliation(s)
- Martin Heine
- RG Molecular Physiology, Leibniz Institute for Neurobiology, Magdeburg, 39118, Germany; Center for Behavioral Brain Sciences, Otto-von-Guericke University, Magdeburg, 39106, Germany; RG Functional Neurobiology, Institute for Development Biology and Neurobiology, Johannes Gutenberg University Mainz, Germany.
| | - Jennifer Heck
- RG Molecular Physiology, Leibniz Institute for Neurobiology, Magdeburg, 39118, Germany
| | - Anna Ciuraszkiewicz
- RG Molecular Physiology, Leibniz Institute for Neurobiology, Magdeburg, 39118, Germany; Center for Behavioral Brain Sciences, Otto-von-Guericke University, Magdeburg, 39106, Germany
| | - Arthur Bikbaev
- RG Molecular Physiology, Leibniz Institute for Neurobiology, Magdeburg, 39118, Germany
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29
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Lübbert M, Goral RO, Keine C, Thomas C, Guerrero-Given D, Putzke T, Satterfield R, Kamasawa N, Young SM. Ca V2.1 α 1 Subunit Expression Regulates Presynaptic Ca V2.1 Abundance and Synaptic Strength at a Central Synapse. Neuron 2018; 101:260-273.e6. [PMID: 30545599 DOI: 10.1016/j.neuron.2018.11.028] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2018] [Revised: 10/22/2018] [Accepted: 11/15/2018] [Indexed: 11/28/2022]
Abstract
The abundance of presynaptic CaV2 voltage-gated Ca2+ channels (CaV2) at mammalian active zones (AZs) regulates the efficacy of synaptic transmission. It is proposed that presynaptic CaV2 levels are saturated in AZs due to a finite number of slots that set CaV2 subtype abundance and that CaV2.1 cannot compete for CaV2.2 slots. However, at most AZs, CaV2.1 levels are highest and CaV2.2 levels are developmentally reduced. To investigate CaV2.1 saturation states and preference in AZs, we overexpressed the CaV2.1 and CaV2.2 α1 subunits at the calyx of Held at immature and mature developmental stages. We found that AZs prefer CaV2.1 to CaV2.2. Remarkably, CaV2.1 α1 subunit overexpression drove increased CaV2.1 currents and channel numbers and increased synaptic strength at both developmental stages examined. Therefore, we propose that CaV2.1 levels in the AZ are not saturated and that synaptic strength can be modulated by increasing CaV2.1 levels to regulate neuronal circuit output. VIDEO ABSTRACT.
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Affiliation(s)
- Matthias Lübbert
- Research Group Molecular Mechanisms of Synaptic Function, Max Planck Florida Institute for Neuroscience, Jupiter, FL 33458, USA
| | - R Oliver Goral
- Department of Anatomy and Cell Biology, Iowa Neuroscience Institute, University of Iowa, Iowa City, IA 52242, USA
| | - Christian Keine
- Department of Anatomy and Cell Biology, Iowa Neuroscience Institute, University of Iowa, Iowa City, IA 52242, USA
| | - Connon Thomas
- Max Planck Florida Electron Microscopy Core, Max Planck Florida Institute for Neuroscience, Jupiter, FL 33458, USA
| | - Debbie Guerrero-Given
- Max Planck Florida Electron Microscopy Core, Max Planck Florida Institute for Neuroscience, Jupiter, FL 33458, USA
| | - Travis Putzke
- Research Group Molecular Mechanisms of Synaptic Function, Max Planck Florida Institute for Neuroscience, Jupiter, FL 33458, USA
| | - Rachel Satterfield
- Research Group Molecular Mechanisms of Synaptic Function, Max Planck Florida Institute for Neuroscience, Jupiter, FL 33458, USA
| | - Naomi Kamasawa
- Max Planck Florida Electron Microscopy Core, Max Planck Florida Institute for Neuroscience, Jupiter, FL 33458, USA
| | - Samuel M Young
- Department of Anatomy and Cell Biology, Iowa Neuroscience Institute, University of Iowa, Iowa City, IA 52242, USA; Department of Otolaryngology, Iowa Neuroscience Institute, Aging Mind Brain Initiative, University of Iowa, Iowa City, IA 52242, USA.
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30
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Martínez Damonte V, Rodríguez SS, Raingo J. Growth hormone secretagogue receptor constitutive activity impairs voltage-gated calcium channel-dependent inhibitory neurotransmission in hippocampal neurons. J Physiol 2018; 596:5415-5428. [PMID: 30199095 DOI: 10.1113/jp276256] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2018] [Accepted: 09/06/2018] [Indexed: 12/14/2022] Open
Abstract
KEY POINTS Presynaptic CaV 2 voltage-gated calcium channels link action potentials arriving at the presynaptic terminal to neurotransmitter release. Hence, their regulation is essential to fine tune brain circuitry. CaV 2 channels are highly sensitive to G protein-coupled receptor (GPCR) modulation. Our previous data indicated that growth hormone secretagogue receptor (GHSR) constitutive activity impairs CaV 2 channels by decreasing their surface density. We present compelling support for the impact of CaV 2.2 channel inhibition by agonist-independent GHSR activity exclusively on GABA release in hippocampal cultures. We found that this selectivity arises from a high reliance of GABA release on CaV 2.2 rather than on CaV 2.1 channels. Our data provide new information on the effects of the ghrelin-GHSR system on synaptic transmission, suggesting a putative physiological role of the constitutive signalling of a GPCR that is expressed at high levels in brain areas with restricted access to its natural agonist. ABSTRACT Growth hormone secretagogue receptor (GHSR) displays high constitutive activity, independent of its endogenous ligand, ghrelin. Unlike ghrelin-induced GHSR activity, the physiological role of GHSR constitutive activity and the mechanisms that underlie GHSR neuronal modulation remain elusive. We previously demonstrated that GHSR constitutive activity modulates presynaptic CaV 2 voltage-gated calcium channels. Here we postulate that GHSR constitutive activity-mediated modulation of CaV 2 channels could be relevant in the hippocampus since this brain area has high GHSR expression but restricted access to ghrelin. We performed whole-cell patch-clamp in hippocampal primary cultures from E16- to E18-day-old C57BL6 wild-type and GHSR-deficient mice after manipulating GHSR expression with lentiviral transduction. We found that GHSR constitutive activity impairs CaV 2.1 and CaV 2.2 native calcium currents and that CaV 2.2 basal impairment leads to a decrease in GABA but not glutamate release. We postulated that this selective effect is related to a higher CaV 2.2 over CaV 2.1 contribution to GABA release (∼40% for CaV 2.2 in wild-type vs. ∼20% in wild-type GHSR-overexpressing cultures). This effect of GHSR constitutive activity is conserved in hippocampal brain slices, where GHSR constitutive activity reduces local GABAergic transmission of the granule cell layer (intra-granule cell inhibitory postsynaptic current (IPSC) size ∼-67 pA in wild-type vs. ∼-100 pA in GHSR-deficient mice), whereas the glutamatergic output from the dentate gyrus to CA3 remains unchanged. In summary, we found that GHSR constitutive activity impairs IPSCs both in hippocampal primary cultures and in brain slices through a CaV 2-dependent mechanism without affecting glutamatergic transmission.
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Affiliation(s)
- Valentina Martínez Damonte
- Multidisciplinary Institute of Cell Biology (IMBICE), National Council of Science and Technology (CONICET), Buenos Aires Comision of Science (CIC) and La Plata University (UNLP), La Plata, Argentina
| | - Silvia Susana Rodríguez
- Multidisciplinary Institute of Cell Biology (IMBICE), National Council of Science and Technology (CONICET), Buenos Aires Comision of Science (CIC) and La Plata University (UNLP), La Plata, Argentina
| | - Jesica Raingo
- Multidisciplinary Institute of Cell Biology (IMBICE), National Council of Science and Technology (CONICET), Buenos Aires Comision of Science (CIC) and La Plata University (UNLP), La Plata, Argentina
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31
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Castagnola S, Delhaye S, Folci A, Paquet A, Brau F, Duprat F, Jarjat M, Grossi M, Béal M, Martin S, Mantegazza M, Bardoni B, Maurin T. New Insights Into the Role of Ca v2 Protein Family in Calcium Flux Deregulation in Fmr1-KO Neurons. Front Mol Neurosci 2018; 11:342. [PMID: 30319351 PMCID: PMC6170614 DOI: 10.3389/fnmol.2018.00342] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2018] [Accepted: 08/30/2018] [Indexed: 12/31/2022] Open
Abstract
Fragile X syndrome (FXS), the most common form of inherited intellectual disability (ID) and a leading cause of autism, results from the loss of expression of the Fmr1 gene which encodes the RNA-binding protein Fragile X Mental Retardation Protein (FMRP). Among the thousands mRNA targets of FMRP, numerous encode regulators of ion homeostasis. It has also been described that FMRP directly interacts with Ca2+ channels modulating their activity. Collectively these findings suggest that FMRP plays critical roles in Ca2+ homeostasis during nervous system development. We carried out a functional analysis of Ca2+ regulation using a calcium imaging approach in Fmr1-KO cultured neurons and we show that these cells display impaired steady state Ca2+ concentration and an altered entry of Ca2+ after KCl-triggered depolarization. Consistent with these data, we show that the protein product of the Cacna1a gene, the pore-forming subunit of the Cav2.1 channel, is less expressed at the plasma membrane of Fmr1-KO neurons compared to wild-type (WT). Thus, our findings point out the critical role that Cav2.1 plays in the altered Ca2+ flux in Fmr1-KO neurons, impacting Ca2+ homeostasis of these cells. Remarkably, we highlight a new phenotype of cultured Fmr1-KO neurons that can be considered a novel cellular biomarker and is amenable to small molecule screening and identification of new drugs to treat FXS.
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Affiliation(s)
- Sara Castagnola
- Université Côte d'Azur, CNRS UMR7275, IPMC, Valbonne, France.,CNRS LIA "Neogenex", Valbonne, France
| | - Sébastien Delhaye
- Université Côte d'Azur, CNRS UMR7275, IPMC, Valbonne, France.,CNRS LIA "Neogenex", Valbonne, France
| | | | - Agnès Paquet
- Université Côte d'Azur, CNRS UMR7275, IPMC, Valbonne, France
| | - Frédéric Brau
- Université Côte d'Azur, CNRS UMR7275, IPMC, Valbonne, France
| | - Fabrice Duprat
- Université Côte d'Azur, INSERM, CNRS UMR7275, IPMC, Valbonne, France
| | - Marielle Jarjat
- Université Côte d'Azur, CNRS UMR7275, IPMC, Valbonne, France.,CNRS LIA "Neogenex", Valbonne, France
| | - Mauro Grossi
- Université Côte d'Azur, CNRS UMR7275, IPMC, Valbonne, France.,CNRS LIA "Neogenex", Valbonne, France
| | - Méline Béal
- Université Côte d'Azur, CNRS UMR7275, IPMC, Valbonne, France.,CNRS LIA "Neogenex", Valbonne, France
| | - Stéphane Martin
- Université Côte d'Azur, INSERM, CNRS UMR7275, IPMC, Valbonne, France
| | | | - Barbara Bardoni
- CNRS LIA "Neogenex", Valbonne, France.,Université Côte d'Azur, INSERM, CNRS UMR7275, IPMC, Valbonne, France
| | - Thomas Maurin
- Université Côte d'Azur, CNRS UMR7275, IPMC, Valbonne, France.,CNRS LIA "Neogenex", Valbonne, France
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Kusuyama K, Tachibana T, Yamanaka H, Okubo M, Yoshiya S, Noguchi K. Upregulation of calcium channel alpha-2-delta-1 subunit in dorsal horn contributes to spinal cord injury-induced tactile allodynia. Spine J 2018; 18:1062-1069. [PMID: 29355786 DOI: 10.1016/j.spinee.2018.01.010] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/08/2017] [Revised: 12/08/2017] [Accepted: 01/10/2018] [Indexed: 02/03/2023]
Abstract
BACKGROUND CONTEXT Spinal cord injury (SCI) commonly results not only in motor paralysis but also in the emergence of neuropathic pain (NeuP), both of which can impair the quality of life for patients with SCI. In the clinical field, it is well known that pregabalin, which binds to the voltage-gated calcium channel alpha-2-delta-1 (α2δ-1) subunit has therapeutic effects on NeuP after SCI. A previous study has demonstrated that SCI increased α2δ-1 in the L4-L6 dorsal spinal cord of SCI rats by Western blot analysis and that the increase of α2δ-1 was correlated with tactile allodynia of the hind paw. However, the detailed feature of an increase in α2δ-1 protein in the spinal dorsal horn and the mechanism of pregabalin effect on SCI-induced NeuP have not been fully examined. PURPOSE This study aimed to examine the detailed distribution of α2δ-1 expression in the lumbar spinal cord after thoracic SCI in rats and the correlation of the therapeutic effect of pregabalin in SCI rats. STUDY DESIGN Male Sprague-Dawley rats underwent thoracic (T10) spinal cord contusion injury using the IH impactor device. Spinal cord injury rats received pregabalin (30 mg/kg) once a day for 2 weeks over a 4-week period after SCI. METHODS The mechanical threshold in the rat hind paw was measured over 4 weeks. Alpha-2-delta-1 expression in the lumbar spinal cord and in the dorsal root ganglion (DRG) was analyzed using immunohistochemistry and in situ hybridization histochemistry. RESULTS A significant reduction of the withdrawal threshold of mechanical stimuli to the hind paw was observed for 2 weeks and continued at least 4 weeks after SCI. In the control rats, expression of α2δ-1 immunoreactivity was detected mainly in laminae I and II in the lumbar dorsal horn. Thoracic SCI significantly increased α2δ-1 immunoreactivity in laminae I and II in the lumbar dorsal horn 4 weeks after SCI; however, thoracic SCI did not affect the expression of α2δ-1 mRNA in the L4 and L5 DRGs. Meanwhile, the signal intensity of α2δ-1 mRNAs in the lumbar spinal cord increased from Day 7 and continued for at least 28 days after SCI. Cellular analysis showed that SCI increased the number of α2δ-1-expressing cells in laminae I and II. The tactile allodynia of the hind paw in the SCI rats was reversed after pregabalin treatment and was maintained for 21 days. This administration of pregabalin decreased the α2δ-1 immunoreactivity significantly in the lumbar dorsal horn of thoracic SCI rats at 28 days after SCI. CONCLUSIONS The present study results suggest that an increase of α2δ-1 in the L4 and L5 dorsal horns after thoracic SCI is derived from the increase in the expression in lumbar spinal neurons. This increase may be involved in the development of NeuP in the hind paws and the therapeutic effect of pregabalin on central NeuP after SCI.
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Affiliation(s)
- Kazuki Kusuyama
- Department of Orthopaedic Surgery, Hyogo College of Medicine, Mukogawa-cho 1-1, Nishinomiya, Hyogo 663-8501, Japan; Department of Anatomy and Neuroscience, Hyogo College of Medicine, 1-1 Mukogawa-cho, Nishinomiya, Hyogo 663-8501, Japan
| | - Toshiya Tachibana
- Department of Orthopaedic Surgery, Hyogo College of Medicine, Mukogawa-cho 1-1, Nishinomiya, Hyogo 663-8501, Japan.
| | - Hiroki Yamanaka
- Department of Anatomy and Neuroscience, Hyogo College of Medicine, 1-1 Mukogawa-cho, Nishinomiya, Hyogo 663-8501, Japan
| | - Masamichi Okubo
- Department of Anatomy and Neuroscience, Hyogo College of Medicine, 1-1 Mukogawa-cho, Nishinomiya, Hyogo 663-8501, Japan
| | - Shinichi Yoshiya
- Department of Orthopaedic Surgery, Hyogo College of Medicine, Mukogawa-cho 1-1, Nishinomiya, Hyogo 663-8501, Japan
| | - Koichi Noguchi
- Department of Anatomy and Neuroscience, Hyogo College of Medicine, 1-1 Mukogawa-cho, Nishinomiya, Hyogo 663-8501, Japan
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33
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Thalhammer A, Contestabile A, Ermolyuk YS, Ng T, Volynski KE, Soong TW, Goda Y, Cingolani LA. Alternative Splicing of P/Q-Type Ca 2+ Channels Shapes Presynaptic Plasticity. Cell Rep 2018; 20:333-343. [PMID: 28700936 DOI: 10.1016/j.celrep.2017.06.055] [Citation(s) in RCA: 44] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2017] [Revised: 06/04/2017] [Accepted: 06/21/2017] [Indexed: 12/26/2022] Open
Abstract
Alternative splicing of pre-mRNAs is prominent in the mammalian brain, where it is thought to expand proteome diversity. For example, alternative splicing of voltage-gated Ca2+ channel (VGCC) α1 subunits can generate thousands of isoforms with differential properties and expression patterns. However, the impact of this molecular diversity on brain function, particularly on synaptic transmission, which crucially depends on VGCCs, is unclear. Here, we investigate how two major splice isoforms of P/Q-type VGCCs (Cav2.1[EFa/b]) regulate presynaptic plasticity in hippocampal neurons. We find that the efficacy of P/Q-type VGCC isoforms in supporting synaptic transmission is markedly different, with Cav2.1[EFa] promoting synaptic depression and Cav2.1[EFb] synaptic facilitation. Following a reduction in network activity, hippocampal neurons upregulate selectively Cav2.1[EFa], the isoform exhibiting the higher synaptic efficacy, thus effectively supporting presynaptic homeostatic plasticity. Therefore, the balance between VGCC splice variants at the synapse is a key factor in controlling neurotransmitter release and presynaptic plasticity.
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Affiliation(s)
- Agnes Thalhammer
- Center for Synaptic Neuroscience and Technology, Istituto Italiano di Tecnologia, Genova 16132, Italy
| | - Andrea Contestabile
- Department of Neuroscience and Brain Technologies, Istituto Italiano di Tecnologia, Genova 16163, Italy
| | | | - Teclise Ng
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117456, Singapore; National Neuroscience Institute, 11 Jalan Tan Tock Seng, Singapore 308433, Singapore
| | | | - Tuck Wah Soong
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117456, Singapore; National Neuroscience Institute, 11 Jalan Tan Tock Seng, Singapore 308433, Singapore
| | - Yukiko Goda
- RIKEN Brain Science Institute, Wako, Saitama 351-0198, Japan
| | - Lorenzo A Cingolani
- Center for Synaptic Neuroscience and Technology, Istituto Italiano di Tecnologia, Genova 16132, Italy.
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Brocard J, Dufour F, Gory-Fauré S, Arnoult C, Bosc C, Denarier E, Peris L, Saoudi Y, De Waard M, Andrieux A. MAP6 interacts with Tctex1 and Ca v 2.2/N-type calcium channels to regulate calcium signalling in neurons. Eur J Neurosci 2017; 46:2754-2767. [PMID: 29094416 PMCID: PMC5765474 DOI: 10.1111/ejn.13766] [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: 07/05/2017] [Revised: 10/20/2017] [Accepted: 10/23/2017] [Indexed: 11/29/2022]
Abstract
MAP6 proteins were first described as microtubule‐stabilizing agents, whose properties were thought to be essential for neuronal development and maintenance of complex neuronal networks. However, deletion of all MAP6 isoforms in MAP6 KO mice does not lead to dramatic morphological aberrations of the brain but rather to alterations in multiple neurotransmissions and severe behavioural impairments. A search for protein partners of MAP6 proteins identified Tctex1 – a dynein light chain with multiple non‐microtubule‐related functions. The involvement of Tctex1 in calcium signalling led to investigate it in MAP6 KO neurons. In this study, we show that functional Cav2.2/N‐type calcium channels are deficient in MAP6 KO neurons, due to improper location. We also show that MAP6 proteins interact directly with both Tctex1 and the C‐terminus of Cav2.2/N‐type calcium channels. A balance of these two interactions seems to be crucial for MAP6 to modulate calcium signalling in neurons.
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Affiliation(s)
- Jacques Brocard
- U1216, INSERM, Grenoble, F-38000, France.,Grenoble Institute of Neuroscience, Université Grenoble Alpes, Grenoble, France
| | - Fabrice Dufour
- U1216, INSERM, Grenoble, F-38000, France.,Grenoble Institute of Neuroscience, Université Grenoble Alpes, Grenoble, France
| | - Sylvie Gory-Fauré
- U1216, INSERM, Grenoble, F-38000, France.,Grenoble Institute of Neuroscience, Université Grenoble Alpes, Grenoble, France
| | - Christophe Arnoult
- U1209, INSERM, Grenoble, France.,UMR 5309, CNRS, Grenoble, France.,Institute for Advanced Biosciences, Université Grenoble Alpes, Grenoble, France
| | - Christophe Bosc
- U1216, INSERM, Grenoble, F-38000, France.,Grenoble Institute of Neuroscience, Université Grenoble Alpes, Grenoble, France
| | - Eric Denarier
- U1216, INSERM, Grenoble, F-38000, France.,Grenoble Institute of Neuroscience, Université Grenoble Alpes, Grenoble, France.,CEA, BIG-GPC, Grenoble, France
| | - Leticia Peris
- U1216, INSERM, Grenoble, F-38000, France.,Grenoble Institute of Neuroscience, Université Grenoble Alpes, Grenoble, France
| | - Yasmina Saoudi
- U1216, INSERM, Grenoble, F-38000, France.,Grenoble Institute of Neuroscience, Université Grenoble Alpes, Grenoble, France
| | - Michel De Waard
- U1087, INSERM, Nantes, France.,UMR 6291, CNRS, Nantes, France.,Université Nantes, Nantes, France
| | - Annie Andrieux
- U1216, INSERM, Grenoble, F-38000, France.,Grenoble Institute of Neuroscience, Université Grenoble Alpes, Grenoble, France.,CEA, BIG-GPC, Grenoble, France
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35
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Scott MB, Kammermeier PJ. Ca V2 channel subtype expression in rat sympathetic neurons is selectively regulated by α 2δ subunits. Channels (Austin) 2017; 11:555-573. [PMID: 28837380 DOI: 10.1080/19336950.2017.1356954] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Type two voltage gated calcium (CaV2) channels are the primary mediators of neurotransmission at neuronal presynapses, but their function at neural soma is also important in regulating excitability. 1 Mechanisms that regulate CaV2 channel expression at synapses have been studied extensively, which motivated us to perform similar studies in the soma. Rat sympathetic neurons from the superior cervical ganglion (SCG) natively express CaV2.2 and CaV2.3. 2 We noted previously that heterologous expression of CaV2.1 but not CaV2.2 results in increased calcium current in SCG neurons. 3 In the present study, we extended these observations to show that both CaV2.1 and CaV2.3 expression resulted in increased calcium currents while CaV2.2 expression did not. Further, CaV2.1 could displace native CaV2.2 channels, but CaV2.3 expression could not. Heterologous expression of the individual accessory subunits α2δ-1, α2δ-2, α2δ-3, or β4 alone failed to increase current density, suggesting that the calcium current ceiling when CaV2.2 was over-expressed was not due to lack of these subunits. Interestingly, introduction of recombinant α2δ subunits produced surprising effects on displacement of native CaV2.2 by recombinant channels. Both α2δ-1 and α2δ-2 seemed to promote CaV2.2 displacement by recombinant channel expression, while α2δ-3 appeared to protect CaV2.2 from displacement. Thus, we observe a selective prioritization of CaV channel functional expression in neurons by specific α2δ subunits. These data highlight a new function for α2δ subtypes that could shed light on subtype selectivity of CaV2 membrane expression.
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Affiliation(s)
- Mallory B Scott
- a Departments of Biochemistry and Biophysics , University of Rochester Medical Center , Rochester , NY , USA
| | - Paul J Kammermeier
- b Departments of Pharmacology and Physiology , University of Rochester Medical Center , Rochester , NY , USA
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36
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Lübbert M, Goral RO, Satterfield R, Putzke T, van den Maagdenberg AM, Kamasawa N, Young SM. A novel region in the Ca V2.1 α 1 subunit C-terminus regulates fast synaptic vesicle fusion and vesicle docking at the mammalian presynaptic active zone. eLife 2017; 6. [PMID: 28786379 PMCID: PMC5548488 DOI: 10.7554/elife.28412] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2017] [Accepted: 07/06/2017] [Indexed: 01/23/2023] Open
Abstract
In central nervous system (CNS) synapses, action potential-evoked neurotransmitter release is principally mediated by CaV2.1 calcium channels (CaV2.1) and is highly dependent on the physical distance between CaV2.1 and synaptic vesicles (coupling). Although various active zone proteins are proposed to control coupling and abundance of CaV2.1 through direct interactions with the CaV2.1 α1 subunit C-terminus at the active zone, the role of these interaction partners is controversial. To define the intrinsic motifs that regulate coupling, we expressed mutant CaV2.1 α1 subunits on a CaV2.1 null background at the calyx of Held presynaptic terminal. Our results identified a region that directly controlled fast synaptic vesicle release and vesicle docking at the active zone independent of CaV2.1 abundance. In addition, proposed individual direct interactions with active zone proteins are insufficient for CaV2.1 abundance and coupling. Therefore, our work advances our molecular understanding of CaV2.1 regulation of neurotransmitter release in mammalian CNS synapses.
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Affiliation(s)
- Matthias Lübbert
- Research Group Molecular Mechanisms of Synaptic Function, Max Planck Florida Institute for Neuroscience, Jupiter, United States
| | - R Oliver Goral
- Research Group Molecular Mechanisms of Synaptic Function, Max Planck Florida Institute for Neuroscience, Jupiter, United States.,Department of Anatomy and Cell Biology, University of Iowa, Iowa City, United States
| | - Rachel Satterfield
- Research Group Molecular Mechanisms of Synaptic Function, Max Planck Florida Institute for Neuroscience, Jupiter, United States
| | - Travis Putzke
- Research Group Molecular Mechanisms of Synaptic Function, Max Planck Florida Institute for Neuroscience, Jupiter, United States
| | | | - Naomi Kamasawa
- Max Planck Florida Electron Microscopy Core, Max Planck Florida Institute for Neuroscience, Jupiter, United States
| | - Samuel M Young
- Research Group Molecular Mechanisms of Synaptic Function, Max Planck Florida Institute for Neuroscience, Jupiter, United States.,Department of Anatomy and Cell Biology, University of Iowa, Iowa City, United States.,Department of Otolaryngology, University of Iowa, Iowa City, United States.,Iowa Neuroscience Institute, University of Iowa, Iowa City, United States.,Aging Mind Brain Initiative, University of Iowa, Iowa City, United States
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37
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Voigt A, Freund R, Heck J, Missler M, Obermair GJ, Thomas U, Heine M. Dynamic association of calcium channel subunits at the cellular membrane. NEUROPHOTONICS 2016; 3:041809. [PMID: 27872869 PMCID: PMC5093230 DOI: 10.1117/1.nph.3.4.041809] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/15/2016] [Accepted: 10/10/2016] [Indexed: 05/25/2023]
Abstract
High voltage gated calcium channels (VGCCs) are composed of at least three subunits, one pore forming [Formula: see text]-subunit, an intracellular [Formula: see text]-variant, and a mostly extracellular [Formula: see text]-variant. Interactions between these subunits determine the kinetic properties of VGCCs. It is unclear whether these interactions are stable over time or rather transient. Here, we used single-molecule tracking to investigate the surface diffusion of [Formula: see text]- and [Formula: see text]-subunits at the cell surface. We found that [Formula: see text]-subunits show higher surface mobility than [Formula: see text]-subunits, and that they are only transiently confined together, suggesting a weak association between [Formula: see text]- and [Formula: see text]-subunits. Moreover, we observed that different [Formula: see text]-subunits engage in different degrees of association with the [Formula: see text]-subunit, revealing the tighter interaction of [Formula: see text] with [Formula: see text]. These data indicate a distinct regulation of the [Formula: see text] interaction in VGCC subtypes. We modeled their membrane dynamics in a Monte Carlo simulation using experimentally determined diffusion constants. Our modeling predicts that the ratio of associated [Formula: see text]- and [Formula: see text]-subunits mainly depends on their expression density and confinement in the membrane. Based on the different motilities of particular [Formula: see text]-subunit combinations, we propose that their dynamic assembly and disassembly represent an important mechanism to regulate the signaling properties of VGCC.
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Affiliation(s)
- Andreas Voigt
- Otto-von-Guericke-University of Magdeburg, Lehrstuhl Systemverfahrenstechnik, Universitätsplatz 2, Magdeburg D-39106, Germany
| | - Romy Freund
- Leibniz-Institute of Neurobiology, Research Group Molecular Physiology, Brenneckestrasse 6, Magdeburg D-39118, Germany
| | - Jennifer Heck
- Leibniz-Institute of Neurobiology, Research Group Molecular Physiology, Brenneckestrasse 6, Magdeburg D-39118, Germany
| | - Markus Missler
- Westfälische Wilhelms-University, Institute of Anatomy and Molecular Neurobiology, Vesaliusweg 2, Münster 48149, Germany
| | - Gerald J. Obermair
- Medical University Innsbruck, Division of Physiology, Department of Physiology and Medical Physics, Schöpfstrasse 41, Innsbruck 6020, Austria
| | - Ulrich Thomas
- Leibniz-Institute of Neurobiology, Department Neurochemistry, Brenneckestrasse 6, Magdeburg D-39118, Germany
| | - Martin Heine
- Leibniz-Institute of Neurobiology, Research Group Molecular Physiology, Brenneckestrasse 6, Magdeburg D-39118, Germany
- Otto-von-Guericke-University Magdeburg, Center for Behavioral Brain Sciences (CBBS), Universitätsplatz 2, Magdeburg D-39106, Germany
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38
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Alles SRA, Smith PA. The Anti-Allodynic Gabapentinoids: Myths, Paradoxes, and Acute Effects. Neuroscientist 2016; 23:40-55. [PMID: 27118808 DOI: 10.1177/1073858416628793] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
The gabapentinoids (pregabalin and gabapentin) are first line treatments for neuropathic pain. They exert their actions by binding to the α2δ accessory subunits of voltage-gated Ca2+ channels. Because these subunits interact with critical aspects of the neurotransmitter release process, gabapentinoid binding prevents transmission in nociceptive pathways. Gabapentinoids also reduce plasma membrane expression of voltage-gated Ca2+ channels but this may have little direct bearing on their therapeutic actions. In animal models of neuropathic pain, gabapentinoids exert an anti-allodynic action within 30 minutes but most of their in vitro effects are 30-fold slower, taking at least 17 hours to develop. This difference may relate to increased levels of α2δ expression in the injured nervous system. Thus, in situations where α2δ is experimentally upregulated in vitro, gabapentinoids act within minutes to interrupt trafficking of α2δ subunits to the plasma membrane within nerve terminals. When α2δ is not up-regulated, gabapentinoids act slowly to interrupt trafficking of α2δ protein from cell bodies to nerve terminals. This improved understanding of the mechanism of gabapentinoid action is related to their slowly developing actions in neuropathic pain patients, to the concept that different processes underlie the onset and maintenance of neuropathic pain and to the use of gabapentinoids in management of postsurgical pain.
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Affiliation(s)
- Sascha R A Alles
- 1 Neuroscience and Mental Health Institute and Department of Pharmacology, University of Alberta, Edmonton, Alberta, Canada
| | - Peter A Smith
- 1 Neuroscience and Mental Health Institute and Department of Pharmacology, University of Alberta, Edmonton, Alberta, Canada
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39
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Dolphin AC. Voltage-gated calcium channels and their auxiliary subunits: physiology and pathophysiology and pharmacology. J Physiol 2016; 594:5369-90. [PMID: 27273705 PMCID: PMC5043047 DOI: 10.1113/jp272262] [Citation(s) in RCA: 208] [Impact Index Per Article: 26.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2016] [Accepted: 05/09/2016] [Indexed: 12/22/2022] Open
Abstract
Voltage‐gated calcium channels are essential players in many physiological processes in excitable cells. There are three main subdivisions of calcium channel, defined by the pore‐forming α1 subunit, the CaV1, CaV2 and CaV3 channels. For all the subtypes of voltage‐gated calcium channel, their gating properties are key for the precise control of neurotransmitter release, muscle contraction and cell excitability, among many other processes. For the CaV1 and CaV2 channels, their ability to reach their required destinations in the cell membrane, their activation and the fine tuning of their biophysical properties are all dramatically influenced by the auxiliary subunits that associate with them. Furthermore, there are many diseases, both genetic and acquired, involving voltage‐gated calcium channels. This review will provide a general introduction and then concentrate particularly on the role of auxiliary α2δ subunits in both physiological and pathological processes involving calcium channels, and as a therapeutic target.
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Affiliation(s)
- Annette C Dolphin
- Department of Neuroscience, Physiology and Pharmacology, University College London, Gower Street, London, WC1E 6BT, UK.
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40
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Ronzitti G, Bucci G, Stephens G, Chieregatti E. Raft-partitioning of calcium channels regulates their function. Channels (Austin) 2015; 9:169-70. [PMID: 26102507 DOI: 10.1080/19336950.2015.1063285] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022] Open
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41
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Heyes S, Pratt WS, Rees E, Dahimene S, Ferron L, Owen MJ, Dolphin AC. Genetic disruption of voltage-gated calcium channels in psychiatric and neurological disorders. Prog Neurobiol 2015; 134:36-54. [PMID: 26386135 PMCID: PMC4658333 DOI: 10.1016/j.pneurobio.2015.09.002] [Citation(s) in RCA: 164] [Impact Index Per Article: 18.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2015] [Revised: 09/08/2015] [Accepted: 09/08/2015] [Indexed: 12/15/2022]
Abstract
Voltage-gated calcium channel classification—genes and proteins. Genetic analysis of neuropsychiatric syndromes. Calcium channel genes identified from GWA studies of psychiatric disorders. Rare mutations in calcium channel genes in psychiatric disorders. Pathophysiological sequelae of CACNA1C mutations and polymorphisms. Monogenic disorders resulting from harmful mutations in other voltage-gated calcium channel genes. Changes in calcium channel gene expression in disease. Involvement of voltage-gated calcium channels in early brain development.
This review summarises genetic studies in which calcium channel genes have been connected to the spectrum of neuropsychiatric syndromes, from bipolar disorder and schizophrenia to autism spectrum disorders and intellectual impairment. Among many other genes, striking numbers of the calcium channel gene superfamily have been implicated in the aetiology of these diseases by various DNA analysis techniques. We will discuss how these relate to the known monogenic disorders associated with point mutations in calcium channels. We will then examine the functional evidence for a causative link between these mutations or single nucleotide polymorphisms and the disease processes. A major challenge for the future will be to translate the expanding psychiatric genetic findings into altered physiological function, involvement in the wider pathology of the diseases, and what potential that provides for personalised and stratified treatment options for patients.
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Affiliation(s)
- Samuel Heyes
- Department of Neuroscience, Physiology and Pharmacology, University College London, London WC1E 6BT, UK
| | - Wendy S Pratt
- Department of Neuroscience, Physiology and Pharmacology, University College London, London WC1E 6BT, UK
| | - Elliott Rees
- Medical Research Council Centre for Neuropsychiatric Genetics and Genomics, Neuroscience and Mental Health Research Institute, Institute of Psychological Medicine and Clinical Neurosciences, Cardiff University, Cardiff CF24 4HQ, UK
| | - Shehrazade Dahimene
- Department of Neuroscience, Physiology and Pharmacology, University College London, London WC1E 6BT, UK
| | - Laurent Ferron
- Department of Neuroscience, Physiology and Pharmacology, University College London, London WC1E 6BT, UK
| | - Michael J Owen
- Medical Research Council Centre for Neuropsychiatric Genetics and Genomics, Neuroscience and Mental Health Research Institute, Institute of Psychological Medicine and Clinical Neurosciences, Cardiff University, Cardiff CF24 4HQ, UK
| | - Annette C Dolphin
- Department of Neuroscience, Physiology and Pharmacology, University College London, London WC1E 6BT, UK.
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Althof D, Baehrens D, Watanabe M, Suzuki N, Fakler B, Kulik Á. Inhibitory and excitatory axon terminals share a common nano-architecture of their Cav2.1 (P/Q-type) Ca(2+) channels. Front Cell Neurosci 2015; 9:315. [PMID: 26321916 PMCID: PMC4531237 DOI: 10.3389/fncel.2015.00315] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2015] [Accepted: 07/28/2015] [Indexed: 12/27/2022] Open
Abstract
Tuning of the time course and strength of inhibitory and excitatory neurotransmitter release is fundamental for the precise operation of cortical network activity and is controlled by Ca2+ influx into presynaptic terminals through the high voltage-activated P/Q-type Ca2+ (Cav2.1) channels. Proper channel-mediated Ca2+-signaling critically depends on the topographical arrangement of the channels in the presynaptic membrane. Here, we used high-resolution SDS-digested freeze-fracture replica immunoelectron microscopy together with automatized computational analysis of Cav2.1 immunogold labeling to determine the precise subcellular organization of Cav2.1 channels in both inhibitory and excitatory terminals. Immunoparticles labeling the pore-forming α1 subunit of Cav2.1 channels were enriched over the active zone of the boutons with the number of channels (3–62) correlated with the area of the synaptic membrane. Detailed analysis showed that Cav2.1 channels are non-uniformly distributed over the presynaptic membrane specialization where they are arranged in clusters of an average five channels per cluster covering a mean area with a diameter of about 70 nm. Importantly, clustered arrangement and cluster properties did not show any significant difference between GABAergic and glutamatergic terminals. Our data demonstrate a common nano-architecture of Cav2.1 channels in inhibitory and excitatory boutons in stratum radiatum of the hippocampal CA1 area suggesting that the cluster arrangement is crucial for the precise release of transmitters from the axonal boutons.
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Affiliation(s)
- Daniel Althof
- Institute of Physiology, University of Freiburg Freiburg, Germany
| | - David Baehrens
- Institute of Physiology, University of Freiburg Freiburg, Germany
| | - Masahiko Watanabe
- Department of Anatomy, Graduate School of Medicine, Hokkaido University Sapporo, Japan
| | - Noboru Suzuki
- Department of Animal Genomics, Functional Genomics Institute, Mie University Mie, Japan
| | - Bernd Fakler
- Institute of Physiology, University of Freiburg Freiburg, Germany ; Centre for Biological Signalling Studies, University of Freiburg Freiburg, Germany
| | - Ákos Kulik
- Institute of Physiology, University of Freiburg Freiburg, Germany ; Centre for Biological Signalling Studies, University of Freiburg Freiburg, Germany
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43
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Schneider R, Hosy E, Kohl J, Klueva J, Choquet D, Thomas U, Voigt A, Heine M. Mobility of calcium channels in the presynaptic membrane. Neuron 2015; 86:672-9. [PMID: 25892305 DOI: 10.1016/j.neuron.2015.03.050] [Citation(s) in RCA: 73] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2014] [Revised: 02/03/2015] [Accepted: 03/09/2015] [Indexed: 12/20/2022]
Abstract
Unravelling principles underlying neurotransmitter release are key to understand neural signaling. Here, we describe how surface mobility of voltage-dependent calcium channels (VDCCs) modulates release probabilities (P(r)) of synaptic vesicles (SVs). Coupling distances of <10 to >100 nm have been reported for SVs and VDCCs in different synapses. Tracking individual VDCCs revealed that within hippocampal synapses, ∼60% of VDCCs are mobile while confined to presynaptic membrane compartments. Intracellular Ca(2+) chelation decreased VDCC mobility. Increasing VDCC surface populations by co-expression of the α2δ1 subunit did not alter channel mobility but led to enlarged active zones (AZs) rather than higher channel densities. VDCCs thus scale presynaptic scaffolds to maintain local mobility. We propose that dynamic coupling based on mobile VDCCs supports calcium domain cooperativity and tunes neurotransmitter release by equalizing Pr for docked SVs within AZs.
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Affiliation(s)
- Romy Schneider
- Molecular Physiology Group, Leibniz Institute for Neurobiology, D-39118 Magdeburg, Germany
| | - Eric Hosy
- University of Bordeaux, F-33000 Bordeaux, France; CNRS, Interdisciplinary Institute for Neuroscience, UMR 5297, F-33000 Bordeaux, France
| | - Johannes Kohl
- Harvard University, Department Molecular and Cellular Biology, Cambridge, MA 02138, USA
| | - Julia Klueva
- Molecular Physiology Group, Leibniz Institute for Neurobiology, D-39118 Magdeburg, Germany; Presynaptic Plasticity Group, Leibniz Institute for Neurobiology, D-39118 Magdeburg, Germany
| | - Daniel Choquet
- University of Bordeaux, F-33000 Bordeaux, France; CNRS, Interdisciplinary Institute for Neuroscience, UMR 5297, F-33000 Bordeaux, France; Bordeaux Imaging Center, UMS 3420 CNRS, US4 INSERM, University of Bordeaux, F-33000 Bordeaux, France
| | - Ulrich Thomas
- Department Neurochemistry, Leibniz Institute for Neurobiology, D-39118 Magdeburg, Germany
| | - Andreas Voigt
- Otto-von-Guericke-University Magdeburg, Systemverfahrenstechnik, Universitätsplatz 2, D-39106 Magdeburg, Germany
| | - Martin Heine
- Molecular Physiology Group, Leibniz Institute for Neurobiology, D-39118 Magdeburg, Germany.
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44
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Ash D, Subramanian M, Surolia A, Shaha C. Nitric oxide is the key mediator of death induced by fisetin in human acute monocytic leukemia cells. Am J Cancer Res 2015; 5:481-497. [PMID: 25973292 PMCID: PMC4396042] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2014] [Accepted: 01/05/2015] [Indexed: 06/04/2023] Open
Abstract
Nitric oxide (NO) has been shown to be effective in cancer chemoprevention and therefore drugs that help generate NO would be preferable for combination chemotherapy or solo use. This study shows a new evidence of NO as a mediator of acute leukemia cell death induced by fisetin, a promising chemotherapeutic agent. Fisetin was able to kill THP-1 cells in vivo resulting in tumor shrinkage in the mouse xenograft model. Death induction in vitro was mediated by an increase in NO resulting in double strand DNA breaks and the activation of both the extrinsic and the intrinsic apoptotic pathways. Double strand DNA breaks could be reduced if NO inhibitor was present during fisetin treatment. Fisetin also inhibited the downstream components of the mTORC1 pathway through downregulation of levels of p70 S6 kinase and inducing hypo-phosphorylation of S6 Ri P kinase, eIF4B and eEF2K. NO inhibition restored phosphorylation of downstream effectors of mTORC1 and rescued cells from death. Fisetin induced Ca(2+) entry through L-type Ca(2+) channels and abrogation of Ca(2+) influx reduced caspase activation and cell death. NO increase and increased Ca(2+) were independent phenomenon. It was inferred that apoptotic death of acute monocytic leukemia cells was induced by fisetin through increased generation of NO and elevated Ca(2+) entry activating the caspase dependent apoptotic pathways. Therefore, manipulation of NO production could be viewed as a potential strategy to increase efficacy of chemotherapy in acute monocytic leukemia.
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Affiliation(s)
- Dipankar Ash
- Cell Death and Differentiation Research Laboratory, National Institute of ImmunologyNew Delhi-110067, India
| | - Manikandan Subramanian
- Cell Death and Differentiation Research Laboratory, National Institute of ImmunologyNew Delhi-110067, India
| | | | - Chandrima Shaha
- Cell Death and Differentiation Research Laboratory, National Institute of ImmunologyNew Delhi-110067, India
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45
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Inchauspe CG, Pilati N, Di Guilmi MN, Urbano FJ, Ferrari MD, van den Maagdenberg AMJM, Forsythe ID, Uchitel OD. Familial hemiplegic migraine type-1 mutated cav2.1 calcium channels alter inhibitory and excitatory synaptic transmission in the lateral superior olive of mice. Hear Res 2014; 319:56-68. [PMID: 25481823 DOI: 10.1016/j.heares.2014.11.006] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/13/2014] [Revised: 11/11/2014] [Accepted: 11/21/2014] [Indexed: 10/24/2022]
Abstract
CaV2.1 Ca(2+) channels play a key role in triggering neurotransmitter release and mediating synaptic transmission. Familial hemiplegic migraine type-1 (FHM-1) is caused by missense mutations in the CACNA1A gene that encodes the α1A pore-forming subunit of CaV2.1 Ca(2+) channels. We used knock-in (KI) transgenic mice harbouring the pathogenic FHM-1 mutation R192Q to study inhibitory and excitatory neurotransmission in the principle neurons of the lateral superior olive (LSO) in the auditory brainstem. We tested if the R192Q FHM-1 mutation differentially affects excitatory and inhibitory synaptic transmission, disturbing the normal balance between excitation and inhibition in this nucleus. Whole cell patch-clamp was used to measure neurotransmitter elicited excitatory (EPSCs) and inhibitory (IPSCs) postsynaptic currents in wild-type (WT) and R192Q KI mice. Our results showed that the FHM-1 mutation in CaV2.1 channels has multiple effects. Evoked EPSC amplitudes were smaller whereas evoked and miniature IPSC amplitudes were larger in R192Q KI compared to WT mice. In addition, in R192Q KI mice, the release probability was enhanced compared to WT, at both inhibitory (0.53 ± 0.02 vs. 0.44 ± 0.01, P = 2.10(-5), Student's t-test) and excitatory synapses (0.60 ± 0.03 vs. 0.45 ± 0.02, P = 4 10(-6), Student's t-test). Vesicle pool size was diminished in R192Q KI mice compared to WT mice (68 ± 6 vs 91 ± 7, P = 0.008, inhibitory; 104 ± 13 vs 335 ± 30, P = 10(-6), excitatory, Student's t-test). R192Q KI mice present enhanced short-term plasticity. Repetitive stimulation of the afferent axons caused short-term depression (STD) of E/IPSCs that recovered significantly faster in R192Q KI mice compared to WT. This supports the hypothesis of a gain-of-function of the CaV2.1 channels in R192Q KI mice, which alters the balance of excitatory/inhibitory inputs and could also have implications in the altered cortical excitability responsible for FHM pathology.
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Affiliation(s)
- Carlota González Inchauspe
- Instituto de Fisiología, Biología molecular y Neurociencias, CONICET, Departamento de Fisiología, Biología Molecular y Celular, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Argentina.
| | - Nadia Pilati
- Dept Cell Physiology & Pharmacology, University of Leicester, LE1 9HN, UK.
| | - Mariano N Di Guilmi
- Instituto de Fisiología, Biología molecular y Neurociencias, CONICET, Departamento de Fisiología, Biología Molecular y Celular, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Argentina
| | - Francisco J Urbano
- Instituto de Fisiología, Biología molecular y Neurociencias, CONICET, Departamento de Fisiología, Biología Molecular y Celular, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Argentina
| | - Michel D Ferrari
- Department of Neurology, Leiden University Medical Centre, P.O. Box 9600, 2300 RC Leiden, The Netherlands
| | - Arn M J M van den Maagdenberg
- Department of Neurology, Leiden University Medical Centre, P.O. Box 9600, 2300 RC Leiden, The Netherlands; Department of Human Genetics, Leiden University Medical Centre, P.O. Box 9600, 2300 RC Leiden, The Netherlands
| | - Ian D Forsythe
- Dept Cell Physiology & Pharmacology, University of Leicester, LE1 9HN, UK
| | - Osvaldo D Uchitel
- Instituto de Fisiología, Biología molecular y Neurociencias, CONICET, Departamento de Fisiología, Biología Molecular y Celular, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Argentina
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46
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Biggs JE, Boakye PA, Ganesan N, Stemkowski PL, Lantero A, Ballanyi K, Smith PA. Analysis of the long-term actions of gabapentin and pregabalin in dorsal root ganglia and substantia gelatinosa. J Neurophysiol 2014; 112:2398-412. [DOI: 10.1152/jn.00168.2014] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The α2δ-ligands pregabalin (PGB) and gabapentin (GBP) are used to treat neuropathic pain. We used whole cell recording to study their long-term effects on substantia gelatinosa and dorsal root ganglion (DRG) neurons. Spinal cord slices were prepared from embryonic day 13 rat embryos and maintained in organotypic culture for >5 wk (neuronal age equivalent to young adult rats). Exposure of similarly aged DRG neurons (dissociated and cultured from postnatal day 19 rats) to GBP or PGB for 5–6 days attenuated high-voltage-activated calcium channel currents (HVA ICa). Strong effects were seen in medium-sized and in small isolectin B4-negative (IB4−) DRG neurons, whereas large neurons and small neurons that bound isolectin B4 (IB4+) were hardly affected. GBP (100 μM) or PGB (10 μM) were less effective than 20 μM Mn2+ in suppression of HVA ICa in small DRG neurons. By contrast, 5–6 days of exposure to these α2δ-ligands was more effective than 20 μM Mn2+ in reducing spontaneous excitatory postsynaptic currents at synapses in substantia gelatinosa. Spinal actions of gabapentinoids cannot therefore be ascribed to decreased expression of HVA Ca2+ channels in primary afferent nerve terminals. In substantia gelatinosa, 5–6 days of exposure to PGB was more effective in inhibiting excitatory synaptic drive to putative excitatory neurons than to putative inhibitory neurons. Although spontaneous inhibitory postsynaptic currents were also attenuated, the overall long-term effect of α2δ-ligands was to decrease network excitability as monitored by confocal Ca2+ imaging. We suggest that selective actions of α2δ-ligands on populations of DRG neurons may predict their selective attenuation of excitatory transmission onto excitatory vs. inhibitory neurons in substantia gelatinosa.
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Affiliation(s)
- James E. Biggs
- Neuroscience and Mental Health Institute, University of Alberta, Edmonton, Canada
- Department of Pharmacology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Canada; and
| | - Paul A. Boakye
- Neuroscience and Mental Health Institute, University of Alberta, Edmonton, Canada
| | - Naren Ganesan
- Neuroscience and Mental Health Institute, University of Alberta, Edmonton, Canada
| | | | - Aquilino Lantero
- Neuroscience and Mental Health Institute, University of Alberta, Edmonton, Canada
- Department of Pharmacology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Canada; and
| | - Klaus Ballanyi
- Neuroscience and Mental Health Institute, University of Alberta, Edmonton, Canada
- Department of Physiology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Canada
| | - Peter A. Smith
- Neuroscience and Mental Health Institute, University of Alberta, Edmonton, Canada
- Department of Pharmacology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Canada; and
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47
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Meriney SD, Umbach JA, Gundersen CB. Fast, Ca2+-dependent exocytosis at nerve terminals: shortcomings of SNARE-based models. Prog Neurobiol 2014; 121:55-90. [PMID: 25042638 DOI: 10.1016/j.pneurobio.2014.07.001] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2013] [Revised: 04/14/2014] [Accepted: 07/03/2014] [Indexed: 11/30/2022]
Abstract
Investigations over the last two decades have made major inroads in clarifying the cellular and molecular events that underlie the fast, synchronous release of neurotransmitter at nerve endings. Thus, appreciable progress has been made in establishing the structural features and biophysical properties of the calcium (Ca2+) channels that mediate the entry into nerve endings of the Ca2+ ions that trigger neurotransmitter release. It is now clear that presynaptic Ca2+ channels are regulated at many levels and the interplay of these regulatory mechanisms is just beginning to be understood. At the same time, many lines of research have converged on the conclusion that members of the synaptotagmin family serve as the primary Ca2+ sensors for the action potential-dependent release of neurotransmitter. This identification of synaptotagmins as the proteins which bind Ca2+ and initiate the exocytotic fusion of synaptic vesicles with the plasma membrane has spurred widespread efforts to reveal molecular details of synaptotagmin's action. Currently, most models propose that synaptotagmin interfaces directly or indirectly with SNARE (soluble, N-ethylmaleimide sensitive factor attachment receptors) proteins to trigger membrane fusion. However, in spite of intensive efforts, the field has not achieved consensus on the mechanism by which synaptotagmins act. Concurrently, the precise sequence of steps underlying SNARE-dependent membrane fusion remains controversial. This review considers the pros and cons of the different models of SNARE-mediated membrane fusion and concludes by discussing a novel proposal in which synaptotagmins might directly elicit membrane fusion without the intervention of SNARE proteins in this final fusion step.
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Affiliation(s)
- Stephen D Meriney
- Department of Neuroscience, Center for Neuroscience, University of Pittsburgh, Pittsburgh, PA 15260, USA
| | - Joy A Umbach
- Department of Molecular and Medical Pharmacology, UCLA David Geffen School of Medicine, Los Angeles, CA 90095, USA
| | - Cameron B Gundersen
- Department of Molecular and Medical Pharmacology, UCLA David Geffen School of Medicine, Los Angeles, CA 90095, USA.
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48
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Davydova D, Marini C, King C, Klueva J, Bischof F, Romorini S, Montenegro-Venegas C, Heine M, Schneider R, Schröder MS, Altrock WD, Henneberger C, Rusakov DA, Gundelfinger ED, Fejtova A. Bassoon specifically controls presynaptic P/Q-type Ca(2+) channels via RIM-binding protein. Neuron 2014; 82:181-94. [PMID: 24698275 DOI: 10.1016/j.neuron.2014.02.012] [Citation(s) in RCA: 118] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/28/2014] [Indexed: 12/11/2022]
Abstract
Voltage-dependent Ca(2+) channels (CaVs) represent the principal source of Ca(2+) ions that trigger evoked neurotransmitter release from presynaptic boutons. Ca(2+) influx is mediated mainly via CaV2.1 (P/Q-type) and CaV2.2 (N-type) channels, which differ in their properties. Their relative contribution to synaptic transmission changes during development and tunes neurotransmission during synaptic plasticity. The mechanism of differential recruitment of CaV2.1 and CaV2.2 to release sites is largely unknown. Here, we show that the presynaptic scaffolding protein Bassoon localizes specifically CaV2.1 to active zones via molecular interaction with the RIM-binding proteins (RBPs). A genetic deletion of Bassoon or an acute interference with Bassoon-RBP interaction reduces synaptic abundance of CaV2.1, weakens P/Q-type Ca(2+) current-driven synaptic transmission, and results in higher relative contribution of neurotransmission dependent on CaV2.2. These data establish Bassoon as a major regulator of the molecular composition of the presynaptic neurotransmitter release sites.
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Affiliation(s)
- Daria Davydova
- Department of Neurochemistry/Molecular Biology, Leibniz Institute for Neurobiology, 39118 Magdeburg, Germany
| | - Claudia Marini
- Department of Neurochemistry/Molecular Biology, Leibniz Institute for Neurobiology, 39118 Magdeburg, Germany
| | - Claire King
- Institute of Neurology, University College London, London WC1N 3BG, UK
| | - Julia Klueva
- Molecular Physiology Group, Leibniz Institute for Neurobiology, 39118 Magdeburg, Germany
| | - Ferdinand Bischof
- Department of Neurochemistry/Molecular Biology, Leibniz Institute for Neurobiology, 39118 Magdeburg, Germany
| | - Stefano Romorini
- Department of Neurochemistry/Molecular Biology, Leibniz Institute for Neurobiology, 39118 Magdeburg, Germany
| | - Carolina Montenegro-Venegas
- Department of Neurochemistry/Molecular Biology, Leibniz Institute for Neurobiology, 39118 Magdeburg, Germany
| | - Martin Heine
- Molecular Physiology Group, Leibniz Institute for Neurobiology, 39118 Magdeburg, Germany
| | - Romy Schneider
- Molecular Physiology Group, Leibniz Institute for Neurobiology, 39118 Magdeburg, Germany
| | - Markus S Schröder
- Department of Neurochemistry/Molecular Biology, Leibniz Institute for Neurobiology, 39118 Magdeburg, Germany
| | - Wilko D Altrock
- Department of Neurochemistry/Molecular Biology, Leibniz Institute for Neurobiology, 39118 Magdeburg, Germany; Center for Behavioral Brain Sciences and Medical Faculty, Otto von Guericke University, 39118 Magdeburg, Germany
| | - Christian Henneberger
- Institute of Neurology, University College London, London WC1N 3BG, UK; Institute of Cellular Neuroscience, Medical Faculty, University of Bonn, 53127 Bonn, Germany
| | - Dmitri A Rusakov
- Institute of Neurology, University College London, London WC1N 3BG, UK
| | - Eckart D Gundelfinger
- Department of Neurochemistry/Molecular Biology, Leibniz Institute for Neurobiology, 39118 Magdeburg, Germany; Center for Behavioral Brain Sciences and Medical Faculty, Otto von Guericke University, 39118 Magdeburg, Germany.
| | - Anna Fejtova
- Department of Neurochemistry/Molecular Biology, Leibniz Institute for Neurobiology, 39118 Magdeburg, Germany; Presynaptic Plasticity Group, Leibniz Institute for Neurobiology, 39118 Magdeburg, Germany.
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49
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Activity-dependent neurotrophin signaling underlies developmental switch of Ca2+ channel subtypes mediating neurotransmitter release. J Neurosci 2014; 33:18755-63. [PMID: 24285882 DOI: 10.1523/jneurosci.3161-13.2013] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
At the nerve terminal, neurotransmitter release is triggered by Ca(2+) influx through voltage-gated Ca(2+) channels (VGCCs). During postnatal development, VGCC subtypes in the nerve terminal switch at many synapses. In immature rodent cerebella, N-type and P/Q-type VGCCs mediate GABAergic neurotransmission from Purkinje cells (PCs) to deep nuclear cells, but as animals mature, neurotransmission becomes entirely P/Q-type dependent. We reproduced this developmental switch in rat cerebellar slice culture to address the underlying mechanism. Chronic block of cerebellar neuronal activity with tetrodotoxin (TTX) in slice culture, or in vivo, reversed the switch, leaving neurotransmission predominantly N-type channel-dependent. Brain-derived neurotrophic factor or neurotrophin-4 rescued this TTX effect, whereas pharmacological blockade of neurotrophin receptors mimicked the TTX effect. In PC somata, unlike in presynaptic terminals, TTX had no effect on the proportion of Ca(2+) channel subtype currents. We conclude that neuronal activity activates the neurotrophin-TrkB signaling pathway, thereby causing the N-to-P/Q channel switch in presynaptic terminals.
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50
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Kang SJ, Liu MG, Shi TY, Zhao MG, Kaang BK, Zhuo M. N-type voltage gated calcium channels mediate excitatory synaptic transmission in the anterior cingulate cortex of adult mice. Mol Pain 2013; 9:58. [PMID: 24228737 PMCID: PMC3842823 DOI: 10.1186/1744-8069-9-58] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2013] [Accepted: 11/04/2013] [Indexed: 12/28/2022] Open
Abstract
Voltage gated calcium channels (VGCCs) are well known for its importance in synaptic transmission in the peripheral and central nervous system. However, the role of different VGCCs in the anterior cingulate cortex (ACC) has not been studied. Here, we use a multi-electrode array recording system (MED64) to study the contribution of different types of calcium channels in glutamatergic excitatory synaptic transmission in the ACC. We found that only the N-type calcium channel blocker ω-conotoxin-GVIA (ω-Ctx-GVIA) produced a great inhibition of basal synaptic transmission, especially in the superficial layer. Other calcium channel blockers that act on L-, P/Q-, R-, and T-type had no effect. We also tested the effects of several neuromodulators with or without ω-Ctx-GVIA. We found that N-type VGCC contributed partially to (1S,3R)-1-aminocyclopentane-1,3-dicarboxylic acid- and (R)-Baclofen-induced synaptic inhibition. By contrast, the inhibitory effects of 2-Chloroadenosine and carbamoylcholine chloride did not differ with or without ω-Ctx-GVIA, indicating that they may act through other mechanisms. Our results provide strong evidence that N-type VGCCs mediate fast synaptic transmission in the ACC.
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Affiliation(s)
| | | | | | | | | | - Min Zhuo
- Department of Brain and Cognitive Sciences, College of Natural Sciences, Seoul National University, Seoul 151-746, South Korea.
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