1
|
Page KM, Gumerov VM, Dahimene S, Zhulin IB, Dolphin AC. The importance of cache domains in α 2δ proteins and the basis for their gabapentinoid selectivity. Channels (Austin) 2023; 17:2167563. [PMID: 36735378 PMCID: PMC9901441 DOI: 10.1080/19336950.2023.2167563] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
In this hybrid review, we have first collected and reviewed available information on the structure and function of the enigmatic cache domains in α2δ proteins. These are organized into two double cache (dCache_1) domains, and they are present in all α2δ proteins. We have also included new data on the key function of these domains with respect to amino acid and gabapentinoid binding to the universal amino acid-binding pocket, which is present in α2δ-1 and α2δ-2. We have now identified the reason why α2δ-3 and α2δ-4 do not bind gabapentinoid drugs or amino acids with bulky side chains. In relation to this, we have determined that the bulky amino acids Tryptophan and Phenylalanine prevent gabapentin from inhibiting cell surface trafficking of α2δ-1. Together, these novel data shed further light on the importance of the cache domains in α2δ proteins.
Collapse
Affiliation(s)
- Karen M Page
- Department of Neuroscience, Physiology and Pharmacology, University College London, London, UK
| | - Vadim M Gumerov
- Department of Microbiology and Translational Data Analytics Institute, The Ohio State University, Columbus, OH, USA
| | - Shehrazade Dahimene
- Department of Neuroscience, Physiology and Pharmacology, University College London, London, UK
| | - Igor B Zhulin
- Department of Microbiology and Translational Data Analytics Institute, The Ohio State University, Columbus, OH, USA
| | - Annette C Dolphin
- Department of Neuroscience, Physiology and Pharmacology, University College London, London, UK
- CONTACT Annette C Dolphin Dolphin Department of Neuroscience, Physiology and Pharmacology, University College London, LondonWC1E 6BT, UK
| |
Collapse
|
2
|
Niere F, Uneri A, McArdle CJ, Deng Z, Egido-Betancourt HX, Cacheaux LP, Namjoshi SV, Taylor WC, Wang X, Barth SH, Reynoldson C, Penaranda J, Stierer MP, Heaney CF, Craft S, Keene CD, Ma T, Raab-Graham KF. Aberrant DJ-1 expression underlies L-type calcium channel hypoactivity in dendrites in tuberous sclerosis complex and Alzheimer's disease. Proc Natl Acad Sci U S A 2023; 120:e2301534120. [PMID: 37903257 PMCID: PMC10636362 DOI: 10.1073/pnas.2301534120] [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: 02/03/2023] [Accepted: 09/25/2023] [Indexed: 11/01/2023] Open
Abstract
L-type voltage-gated calcium (Ca2+) channels (L-VGCC) dysfunction is implicated in several neurological and psychiatric diseases. While a popular therapeutic target, it is unknown whether molecular mechanisms leading to disrupted L-VGCC across neurodegenerative disorders are conserved. Importantly, L-VGCC integrate synaptic signals to facilitate a plethora of cellular mechanisms; however, mechanisms that regulate L-VGCC channel density and subcellular compartmentalization are understudied. Herein, we report that in disease models with overactive mammalian target of rapamycin complex 1 (mTORC1) signaling (or mTORopathies), deficits in dendritic L-VGCC activity are associated with increased expression of the RNA-binding protein (RBP) Parkinsonism-associated deglycase (DJ-1). DJ-1 binds the mRNA coding for the alpha and auxiliary Ca2+ channel subunits CaV1.2 and α2δ2, and represses their mRNA translation, only in the disease states, specifically preclinical models of tuberous sclerosis complex (TSC) and Alzheimer's disease (AD). In agreement, DJ-1-mediated repression of CaV1.2/α2δ2 protein synthesis in dendrites is exaggerated in mouse models of AD and TSC, resulting in deficits in dendritic L-VGCC calcium activity. Finding of DJ-1-regulated L-VGCC activity in dendrites in TSC and AD provides a unique signaling pathway that can be targeted in clinical mTORopathies.
Collapse
Affiliation(s)
- Farr Niere
- Department of Physiology and Pharmacology, Wake Forest University School of Medicine, Winston-Salem, NC27157
- Department of Biology, North Carolina Agricultural and Technical State University, Greensboro, NC27411
| | - Ayse Uneri
- Department of Physiology and Pharmacology, Wake Forest University School of Medicine, Winston-Salem, NC27157
| | - Colin J. McArdle
- Department of Physiology and Pharmacology, Wake Forest University School of Medicine, Winston-Salem, NC27157
| | - Zhiyong Deng
- Department of Physiology and Pharmacology, Wake Forest University School of Medicine, Winston-Salem, NC27157
| | - Hailey X. Egido-Betancourt
- Department of Physiology and Pharmacology, Wake Forest University School of Medicine, Winston-Salem, NC27157
| | - Luisa P. Cacheaux
- Department of Physiology and Pharmacology, Wake Forest University School of Medicine, Winston-Salem, NC27157
| | - Sanjeev V. Namjoshi
- Department of Physiology and Pharmacology, Wake Forest University School of Medicine, Winston-Salem, NC27157
| | - William C. Taylor
- Department of Physiology and Pharmacology, Wake Forest University School of Medicine, Winston-Salem, NC27157
| | - Xin Wang
- Department of Internal Medicine, Gerontology and Geriatric Medicine, Wake Forest University School of Medicine, Winston-Salem, NC27157
| | - Samuel H. Barth
- Department of Physiology and Pharmacology, Wake Forest University School of Medicine, Winston-Salem, NC27157
| | - Cameron Reynoldson
- Department of Physiology and Pharmacology, Wake Forest University School of Medicine, Winston-Salem, NC27157
| | - Juan Penaranda
- Department of Physiology and Pharmacology, Wake Forest University School of Medicine, Winston-Salem, NC27157
| | - Michael P. Stierer
- Department of Physiology and Pharmacology, Wake Forest University School of Medicine, Winston-Salem, NC27157
| | - Chelcie F. Heaney
- Department of Physiology and Pharmacology, Wake Forest University School of Medicine, Winston-Salem, NC27157
| | - Suzanne Craft
- Department of Internal Medicine, Gerontology and Geriatric Medicine, Wake Forest University School of Medicine, Winston-Salem, NC27157
- Wake Forest Alzheimer’s Disease Research Center, Wake Forest University School of Medicine, Winston-Salem, NC27157
| | - C. Dirk Keene
- Department of Laboratory Medicine and Pathology, University of Washington, Seattle, WA98104
| | - Tao Ma
- Department of Physiology and Pharmacology, Wake Forest University School of Medicine, Winston-Salem, NC27157
- Department of Internal Medicine, Gerontology and Geriatric Medicine, Wake Forest University School of Medicine, Winston-Salem, NC27157
| | - Kimberly F. Raab-Graham
- Department of Physiology and Pharmacology, Wake Forest University School of Medicine, Winston-Salem, NC27157
| |
Collapse
|
3
|
Zhao J, Gao L, Nurrish S, Kaplan JM. Post-synaptic GABA A receptors potentiate transmission by recruiting CaV2 channels to their inputs. Cell Rep 2023; 42:113161. [PMID: 37742192 PMCID: PMC10873018 DOI: 10.1016/j.celrep.2023.113161] [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: 02/21/2023] [Revised: 07/05/2023] [Accepted: 09/07/2023] [Indexed: 09/26/2023] Open
Abstract
We describe a retrograde synaptic signal at the C. elegans GABAergic neuromuscular junction. At this synapse, GABA release is controlled by two voltage-activated calcium channels (UNC-2/CaV2 and EGL-19/CaV1), and muscle responses are mediated by a single GABA receptor (UNC-49/GABAA). Mutations inactivating UNC-49 or those preventing UNC-49 synaptic clustering cause retrograde defects in GABAergic motor neurons, whereby UNC-2/CaV2 levels at active zones, UNC-2 current, and pre-synaptic GABA release are decreased. Inactivating post-synaptic GABAA receptors has no effect on GABA neuron EGL-19/CaV1 levels nor on several other pre-synaptic markers. The effect of GABAA receptors on pre-synaptic strength is not a consequence of decreased GABA transmission and is input selective. Finally, pre-synaptic UNC-2/CaV2 levels are increased when post-synaptic GABAA receptors are increased but are unaffected by increased extra-synaptic receptors. Collectively, these results suggest that clustered post-synaptic GABAA receptors adjust the strength of their inputs by recruiting CaV2 to contacting active zones.
Collapse
Affiliation(s)
- Jian Zhao
- Department of Molecular Biology, Massachusetts General Hospital, Boston, MA 02114, USA; Department of Neurobiology, Harvard Medical School, Boston, MA 02115, USA
| | - Luna Gao
- Department of Molecular Biology, Massachusetts General Hospital, Boston, MA 02114, USA; Department of Neurobiology, Harvard Medical School, Boston, MA 02115, USA
| | - Stephen Nurrish
- Department of Molecular Biology, Massachusetts General Hospital, Boston, MA 02114, USA; Department of Neurobiology, Harvard Medical School, Boston, MA 02115, USA
| | - Joshua M Kaplan
- Department of Molecular Biology, Massachusetts General Hospital, Boston, MA 02114, USA; Department of Neurobiology, Harvard Medical School, Boston, MA 02115, USA; Program in Neuroscience, Harvard Medical School, Boston, MA 02115, USA.
| |
Collapse
|
4
|
Stanika R, Obermair GJ. An ex vivo Model of Paired Cultured Hippocampal Neurons for Bi-directionally Studying Synaptic Transmission and Plasticity. Bio Protoc 2023; 13:e4761. [PMID: 37497454 PMCID: PMC10366995 DOI: 10.21769/bioprotoc.4761] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2023] [Revised: 03/25/2023] [Accepted: 05/30/2023] [Indexed: 07/28/2023] Open
Abstract
Synapses provide the main route of signal transduction within neuronal networks. Many factors regulate critical synaptic functions. These include presynaptic calcium channels, triggering neurotransmitter release, and postsynaptic ionotropic receptors, mediating excitatory and inhibitory postsynaptic potentials. The key features of synaptic transmission and plasticity can be studied in primary cultured hippocampal neurons. Here, we describe a protocol for the preparation and electrophysiological analysis of paired hippocampal neurons. This model system allows the selective genetic manipulation of one neuron in a simple neuronal network formed by only two hippocampal neurons. Bi-directionally analyzing synaptic transmission and short-term synaptic plasticity allows the analysis of both pre- and postsynaptic effects on synaptic transmission. For example, with one single paired network synaptic responses induced by both, a wild-type neuron and a genetically modified neuron can be directly compared. Ultimately, this protocol allows experimental modulation and hence investigation of synaptic mechanisms and thereby improves previously developed methods of studying synaptic transmission and plasticity in ex vivo cultured neurons. Key features Preparation of ex vivo paired cultured hippocampal neurons. Bi-directional electrophysiological recordings of synaptic transmission and plasticity. Genetic modulation of synaptic network formation (demonstrated by presynaptic viral overexpression of the auxiliary calcium channel α2δ-2 subunit). Graphical overview.
Collapse
Affiliation(s)
- Ruslan Stanika
- Division of Physiology, Department of Pharmacology, Physiology, and Microbiology, Karl Landsteiner University of Health Sciences, Krems, Austria
| | - Gerald J. Obermair
- Division of Physiology, Department of Pharmacology, Physiology, and Microbiology, Karl Landsteiner University of Health Sciences, Krems, Austria
| |
Collapse
|
5
|
Ortner NJ. CACNA1D-Related Channelopathies: From Hypertension to Autism. Handb Exp Pharmacol 2023. [PMID: 36592224 DOI: 10.1007/164_2022_626] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Tightly controlled Ca2+ influx through voltage-gated Ca2+ channels (Cavs) is indispensable for proper physiological function. Thus, it is not surprising that Cav loss and/or gain of function have been implicated in human pathology. Deficiency of Cav1.3 L-type Ca2+ channels (LTCCs) causes deafness and bradycardia, whereas several genetic variants of CACNA1D, the gene encoding the pore-forming α1 subunit of Cav1.3, have been linked to various disease phenotypes, such as hypertension, congenital hypoglycemia, or autism. These variants include not only common polymorphisms associated with an increased disease risk, but also rare de novo missense variants conferring high risk. This review provides a concise summary of disease-associated CACNA1D variants, whereas the main focus lies on de novo germline variants found in individuals with a neurodevelopmental disorder of variable severity. Electrophysiological recordings revealed activity-enhancing gating changes induced by these de novo variants, and tools to predict their pathogenicity and to study the resulting pathophysiological consequences will be discussed. Despite the low number of affected patients, potential phenotype-genotype correlations and factors that could impact the severity of symptoms will be covered. Since increased channel activity is assumed as the disease-underlying mechanism, pharmacological inhibition could be a treatment option. In the absence of Cav1.3-selective blockers, dihydropyridine LTCC inhibitors clinically approved for the treatment of hypertension may be used for personalized off-label trials. Findings from in vitro studies and treatment attempts in some of the patients seem promising as outlined. Taken together, due to advances in diagnostic sequencing techniques the number of reported CACNA1D variants in human diseases is constantly rising. Evidence from in silico, in vitro, and in vivo disease models can help to predict the pathogenic potential of such variants and to guide diagnosis and treatment in the clinical practice when confronted with patients harboring CACNA1D variants.
Collapse
Affiliation(s)
- Nadine J Ortner
- Department of Pharmacology and Toxicology, Institute of Pharmacy, Center for Molecular Biosciences Innsbruck, University of Innsbruck, Innsbruck, Austria.
| |
Collapse
|
6
|
Hessenberger M, Haddad S, Obermair GJ. Pathophysiological Roles of Auxiliary Calcium Channel α 2δ Subunits. Handb Exp Pharmacol 2023; 279:289-316. [PMID: 36598609 DOI: 10.1007/164_2022_630] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
α2δ proteins serve as auxiliary subunits of voltage-gated calcium channels, which are essential components of excitable cells such as skeletal and heart muscles, nerve cells of the brain and the peripheral nervous system, as well as endocrine cells. Over the recent years, α2δ proteins have been identified as critical regulators of synaptic functions, including the formation and differentiation of synapses. These functions require signalling mechanisms which are partly independent of calcium channels. Hence, in light of these features it is not surprising that the genes encoding for the four α2δ isoforms have recently been linked to neurological and neurodevelopmental disorders including epilepsy, autism spectrum disorders, schizophrenia, and depressive and bipolar disorders. Despite the increasing number of identified disease-associated mutations, the underlying pathophysiological mechanisms are only beginning to emerge. However, a thorough understanding of the pathophysiological role of α2δ proteins ideally serves two purposes: first, it will contribute to our understanding of general pathological mechanisms in synaptic disorders. Second, it may support the future development of novel and specific treatments for brain disorders. In this context, it is noteworthy that the antiepileptic and anti-allodynic drugs gabapentin and pregabalin both act via binding to α2δ proteins and are among the top sold drugs for treating neuropathic pain. In this book chapter, we will discuss recent developments in our understanding of the functions of α2δ proteins, both as calcium channel subunits and as independent regulatory entities. Furthermore, we present and summarize recently identified and likely pathogenic mutations in the genes encoding α2δ proteins and discuss potential underlying pathophysiological consequences at the molecular and structural level.
Collapse
Affiliation(s)
- Manuel Hessenberger
- Division Physiology, Department Pharmacology, Physiology and Microbiology, Karl Landsteiner University of Health Sciences, Krems, Austria
| | - Sabrin Haddad
- Division Physiology, Department Pharmacology, Physiology and Microbiology, Karl Landsteiner University of Health Sciences, Krems, Austria
- Institute of Physiology, Medical University of Innsbruck, Innsbruck, Austria
| | - Gerald J Obermair
- Division Physiology, Department Pharmacology, Physiology and Microbiology, Karl Landsteiner University of Health Sciences, Krems, Austria.
| |
Collapse
|
7
|
Abstract
Voltage-gated Ca2+ (Cav) channels play pivotal roles in regulating gene transcription, neuronal excitability, and neurotransmitter release. To meet the spatial and temporal demands of visual signaling, Cav channels exhibit unusual properties in the retina compared to their counterparts in other areas of the nervous system. In this article, we review current concepts regarding the specific subtypes of Cav channels expressed in the retina, their intrinsic properties and forms of modulation, and how their dysregulation could lead to retinal disease.
Collapse
Affiliation(s)
- Brittany Williams
- Department of Cell Biology & Physiology, Carolina Institute for Developmental Disabilities, and Neuroscience Center, University of North Carolina, Chapel Hill, North Carolina, USA
| | - J Wesley Maddox
- Department of Neuroscience, University of Texas, Austin, Texas, USA;
| | - Amy Lee
- Department of Neuroscience, University of Texas, Austin, Texas, USA;
| |
Collapse
|
8
|
Ablinger C, Eibl C, Geisler SM, Campiglio M, Stephens GJ, Missler M, Obermair GJ. α 2δ-4 and Cachd1 Proteins Are Regulators of Presynaptic Functions. Int J Mol Sci 2022; 23:9885. [PMID: 36077281 PMCID: PMC9456004 DOI: 10.3390/ijms23179885] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2022] [Revised: 08/15/2022] [Accepted: 08/24/2022] [Indexed: 11/17/2022] Open
Abstract
The α2δ auxiliary subunits of voltage-gated calcium channels (VGCC) were traditionally regarded as modulators of biophysical channel properties. In recent years, channel-independent functions of these subunits, such as involvement in synapse formation, have been identified. In the central nervous system, α2δ isoforms 1, 2, and 3 are strongly expressed, regulating glutamatergic synapse formation by a presynaptic mechanism. Although the α2δ-4 isoform is predominantly found in the retina with very little expression in the brain, it was recently linked to brain functions. In contrast, Cachd1, a novel α2δ-like protein, shows strong expression in brain, but its function in neurons is not yet known. Therefore, we aimed to investigate the presynaptic functions of α2δ-4 and Cachd1 by expressing individual proteins in cultured hippocampal neurons. Both α2δ-4 and Cachd1 are expressed in the presynaptic membrane and could rescue a severe synaptic defect present in triple knockout/knockdown neurons that lacked the α2δ-1-3 isoforms (α2δ TKO/KD). This observation suggests that presynaptic localization and the regulation of synapse formation in glutamatergic neurons is a general feature of α2δ proteins. In contrast to this redundant presynaptic function, α2δ-4 and Cachd1 differentially regulate the abundance of presynaptic calcium channels and the amplitude of presynaptic calcium transients. These functional differences may be caused by subtle isoform-specific differences in α1-α2δ protein-protein interactions, as revealed by structural homology modelling. Taken together, our study identifies both α2δ-4 and Cachd1 as presynaptic regulators of synapse formation, differentiation, and calcium channel functions that can at least partially compensate for the loss of α2δ-1-3. Moreover, we show that regulating glutamatergic synapse formation and differentiation is a critical and surprisingly redundant function of α2δ and Cachd1.
Collapse
Affiliation(s)
- Cornelia Ablinger
- Institute of Physiology, Medical University Innsbruck, 6020 Innsbruck, Austria
| | - Clarissa Eibl
- Division Physiology, Department of Pharmacology, Physiology and Microbiology, Karl Landsteiner University of Health Sciences, 3500 Krems, Austria
| | - Stefanie M. Geisler
- Department Pharmacology and Toxicology, University of Innsbruck, 6020 Innsbruck, Austria
| | - Marta Campiglio
- Institute of Physiology, Medical University Innsbruck, 6020 Innsbruck, Austria
| | - Gary J. Stephens
- Reading School of Pharmacy, University of Reading, Reading RG6 6UB, UK
| | - Markus Missler
- Institute of Anatomy and Molecular Neurobiology, Westfälische Wilhelms-University, 48149 Münster, Germany
| | - Gerald J. Obermair
- Institute of Physiology, Medical University Innsbruck, 6020 Innsbruck, Austria
- Division Physiology, Department of Pharmacology, Physiology and Microbiology, Karl Landsteiner University of Health Sciences, 3500 Krems, Austria
| |
Collapse
|
9
|
Klomp A, Omichi R, Iwasa Y, Smith RJ, Usachev YM, Russo AF, Narayanan NS, Lee A. The voltage-gated Ca2+ channel subunit α2δ-4 regulates locomotor behavior and sensorimotor gating in mice. PLoS One 2022; 17:e0263197. [PMID: 35353835 PMCID: PMC8967030 DOI: 10.1371/journal.pone.0263197] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2022] [Accepted: 03/11/2022] [Indexed: 01/06/2023] Open
Abstract
Voltage-gated Ca2+ channels are critical for the development and mature function of the nervous system. Variants in the CACNA2D4 gene encoding the α2δ-4 auxiliary subunit of these channels are associated with neuropsychiatric and neurodevelopmental disorders. α2δ-4 is prominently expressed in the retina and is crucial for vision, but extra-retinal functions of α2δ-4 have not been investigated. Here, we sought to fill this gap by analyzing the behavioral phenotypes of α2δ-4 knockout (KO) mice. α2δ-4 KO mice (both males and females) exhibited significant impairments in prepulse inhibition that were unlikely to result from the modestly elevated auditory brainstem response thresholds. Whereas α2δ-4 KO mice of both sexes were hyperactive in various assays, only females showed impaired motor coordination in the rotarod assay. α2δ-4 KO mice exhibited anxiolytic and anti-depressive behaviors in the elevated plus maze and tail suspension tests, respectively. Our results reveal an unexpected role for α2δ-4 in sensorimotor gating and motor function and identify α2δ-4 KO mice as a novel model for studying the pathophysiology associated with CACNA2D4 variants.
Collapse
Affiliation(s)
- Annette Klomp
- Interdisciplinary Graduate Program in Neuroscience, University of Iowa, Iowa City, Iowa, United States of America
- Iowa Neuroscience Institute, University of Iowa, Iowa City, Iowa, United States of America
- Department of Molecular Physiology and Biophysics, University of Iowa, Iowa City, Iowa, United States of America
| | - Ryotaro Omichi
- Department of Otolaryngology-Head and Neck Surgery, University of Iowa, Iowa City, Iowa, United States of America
- Iowa Institute of Human Genetics, University of Iowa, Iowa City, Iowa, United States of America
| | - Yoichiro Iwasa
- Department of Otolaryngology-Head and Neck Surgery, University of Iowa, Iowa City, Iowa, United States of America
- Iowa Institute of Human Genetics, University of Iowa, Iowa City, Iowa, United States of America
| | - Richard J. Smith
- Iowa Neuroscience Institute, University of Iowa, Iowa City, Iowa, United States of America
- Department of Molecular Physiology and Biophysics, University of Iowa, Iowa City, Iowa, United States of America
- Department of Otolaryngology-Head and Neck Surgery, University of Iowa, Iowa City, Iowa, United States of America
- Iowa Institute of Human Genetics, University of Iowa, Iowa City, Iowa, United States of America
| | - Yuriy M. Usachev
- Iowa Neuroscience Institute, University of Iowa, Iowa City, Iowa, United States of America
- Department of Neuroscience and Pharmacology, University of Iowa, Iowa City, Iowa, United States of America
| | - Andrew F. Russo
- Iowa Neuroscience Institute, University of Iowa, Iowa City, Iowa, United States of America
- Department of Molecular Physiology and Biophysics, University of Iowa, Iowa City, Iowa, United States of America
- Department of Neurology, University of Iowa, Iowa City, Iowa, United States of America
| | - Nandakumar S. Narayanan
- Iowa Neuroscience Institute, University of Iowa, Iowa City, Iowa, United States of America
- Department of Neurology, University of Iowa, Iowa City, Iowa, United States of America
| | - Amy Lee
- Iowa Neuroscience Institute, University of Iowa, Iowa City, Iowa, United States of America
- Department of Molecular Physiology and Biophysics, University of Iowa, Iowa City, Iowa, United States of America
- Department of Otolaryngology-Head and Neck Surgery, University of Iowa, Iowa City, Iowa, United States of America
- Department of Neurology, University of Iowa, Iowa City, Iowa, United States of America
- * E-mail:
| |
Collapse
|
10
|
Impaired Subcortical Processing of Amplitude-Modulated Tones in Mice Deficient for Cacna2d3, a Risk Gene for Autism Spectrum Disorders in Humans. eNeuro 2022; 9:ENEURO.0118-22.2022. [PMID: 35410870 PMCID: PMC9034753 DOI: 10.1523/eneuro.0118-22.2022] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2022] [Accepted: 03/21/2022] [Indexed: 12/18/2022] Open
Abstract
Temporal processing of complex sounds is a fundamental and complex task in hearing and a prerequisite for processing and understanding vocalization, speech, and prosody. Here, we studied response properties of neurons in the inferior colliculus (IC) in mice lacking Cacna2d3, a risk gene for autism spectrum disorders (ASDs). The α2δ3 auxiliary Ca2+ channel subunit encoded by Cacna2d3 is essential for proper function of glutamatergic synapses in the auditory brainstem. Recent evidence has shown that much of auditory feature extraction is performed in the auditory brainstem and IC, including processing of amplitude modulation (AM). We determined both spectral and temporal properties of single- and multi-unit responses in the IC of anesthetized mice. IC units of α2δ3−/− mice showed normal tuning properties yet increased spontaneous rates compared with α2δ3+/+. When stimulated with AM tones, α2δ3−/− units exhibited less precise temporal coding and reduced evoked rates to higher modulation frequencies (fm). Whereas first spike latencies (FSLs) were increased for only few modulation frequencies, population peak latencies were increased for fm ranging from 20 to 100 Hz in α2δ3−/− IC units. The loss of precision of temporal coding with increasing fm from 70 to 160 Hz was characterized using a normalized offset-corrected (Pearson-like) correlation coefficient, which appeared more appropriate than the metrics of vector strength. The processing deficits of AM sounds analyzed at the level of the IC indicate that α2δ3−/− mice exhibit a subcortical auditory processing disorder (APD). Similar deficits may be present in other mouse models for ASDs.
Collapse
|
11
|
Tuluc P, Theiner T, Jacobo-Piqueras N, Geisler SM. Role of High Voltage-Gated Ca 2+ Channel Subunits in Pancreatic β-Cell Insulin Release. From Structure to Function. Cells 2021; 10:2004. [PMID: 34440773 PMCID: PMC8393260 DOI: 10.3390/cells10082004] [Citation(s) in RCA: 9] [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: 06/07/2021] [Revised: 07/27/2021] [Accepted: 08/03/2021] [Indexed: 02/07/2023] Open
Abstract
The pancreatic islets of Langerhans secrete several hormones critical for glucose homeostasis. The β-cells, the major cellular component of the pancreatic islets, secrete insulin, the only hormone capable of lowering the plasma glucose concentration. The counter-regulatory hormone glucagon is secreted by the α-cells while δ-cells secrete somatostatin that via paracrine mechanisms regulates the α- and β-cell activity. These three peptide hormones are packed into secretory granules that are released through exocytosis following a local increase in intracellular Ca2+ concentration. The high voltage-gated Ca2+ channels (HVCCs) occupy a central role in pancreatic hormone release both as a source of Ca2+ required for excitation-secretion coupling as well as a scaffold for the release machinery. HVCCs are multi-protein complexes composed of the main pore-forming transmembrane α1 and the auxiliary intracellular β, extracellular α2δ, and transmembrane γ subunits. Here, we review the current understanding regarding the role of all HVCC subunits expressed in pancreatic β-cell on electrical activity, excitation-secretion coupling, and β-cell mass. The evidence we review was obtained from many seminal studies employing pharmacological approaches as well as genetically modified mouse models. The significance for diabetes in humans is discussed in the context of genetic variations in the genes encoding for the HVCC subunits.
Collapse
Affiliation(s)
- Petronel Tuluc
- Centre for Molecular Biosciences, Department of Pharmacology and Toxicology, University of Innsbruck, Innrain 80/82, 6020 Innsbruck, Austria; (T.T.); (N.J.-P.); (S.M.G.)
| | | | | | | |
Collapse
|
12
|
Regulation of GABA A Receptors Induced by the Activation of L-Type Voltage-Gated Calcium Channels. MEMBRANES 2021; 11:membranes11070486. [PMID: 34209589 PMCID: PMC8304739 DOI: 10.3390/membranes11070486] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/21/2021] [Revised: 06/23/2021] [Accepted: 06/25/2021] [Indexed: 12/30/2022]
Abstract
GABAA receptors are pentameric ion channels that mediate most synaptic and tonic extrasynaptic inhibitory transmissions in the central nervous system. There are multiple GABAA receptor subtypes constructed from 19 different subunits in mammals that exhibit different regional and subcellular distributions and distinct pharmacological properties. Dysfunctional alterations of GABAA receptors are associated with various neuropsychiatric disorders. Short- and long-term plastic changes in GABAA receptors can be induced by the activation of different intracellular signaling pathways that are triggered, under physiological and pathological conditions, by calcium entering through voltage-gated calcium channels. This review discusses several mechanisms of regulation of GABAA receptor function that result from the activation of L-type voltage gated calcium channels. Calcium influx via these channels activates different signaling cascades that lead to changes in GABAA receptor transcription, phosphorylation, trafficking, and synaptic clustering, thus regulating the inhibitory synaptic strength. These plastic mechanisms regulate the interplay of synaptic excitation and inhibition that is crucial for the normal function of neuronal circuits.
Collapse
|
13
|
Meyer JO, Dolphin AC. Rab11-dependent recycling of calcium channels is mediated by auxiliary subunit α 2δ-1 but not α 2δ-3. Sci Rep 2021; 11:10256. [PMID: 33986433 PMCID: PMC8119971 DOI: 10.1038/s41598-021-89820-1] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2021] [Accepted: 04/16/2021] [Indexed: 11/18/2022] Open
Abstract
N-type voltage-gated calcium channels (CaV2.2) are predominantly expressed at presynaptic terminals, and their function is regulated by auxiliary α2δ and β subunits. All four mammalian α2δ subunits enhance calcium currents through CaV1 and CaV2 channels, and this increase is attributed, in part, to increased CaV expression at the plasma membrane. In the present study we provide evidence that α2δ-1, like α2δ-2, is recycled to the plasma membrane through a Rab11a-dependent endosomal recycling pathway. Using a dominant-negative Rab11a mutant, Rab11a(S25N), we show that α2δ-1 increases plasma membrane CaV2.2 expression by increasing the rate and extent of net forward CaV2.2 trafficking in a Rab11a-dependent manner. Dominant-negative Rab11a also reduces the ability of α2δ-1 to increase CaV2.2 expression on the cell-surface of hippocampal neurites. In contrast, α2δ-3 does not enhance rapid forward CaV2.2 trafficking, regardless of whether Rab11a(S25N) is present. In addition, whole-cell CaV2.2 currents are reduced by co-expression of Rab11a(S25N) in the presence of α2δ-1, but not α2δ-3. Taken together these data suggest that α2δ subtypes participate in distinct trafficking pathways which in turn influence the localisation and function of CaV2.2.
Collapse
Affiliation(s)
- James O Meyer
- Department of Neuroscience, Physiology and Pharmacology, University College London, Gower Street, London, WC1E 6BT, UK
| | - Annette C Dolphin
- Department of Neuroscience, Physiology and Pharmacology, University College London, Gower Street, London, WC1E 6BT, UK.
| |
Collapse
|
14
|
Melatonin Exerts Anti-Inflammatory, Antioxidant, and Neuromodulatory Effects That Could Potentially Be Useful in the Treatment of Vertigo. Int J Otolaryngol 2021; 2021:6641055. [PMID: 33859698 PMCID: PMC8009714 DOI: 10.1155/2021/6641055] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2020] [Revised: 03/10/2021] [Accepted: 03/15/2021] [Indexed: 12/18/2022] Open
Abstract
The acute phase of vertigo involves multiple neurotransmitters, inflammatory mediators, and products of oxidative stress. The vestibular pathway has multiple melatonin receptors distributed along its path, both centrally and peripherally. In addition, melatonin has been shown to be a powerful antioxidant and anti-inflammatory agent against factors related to vertigo, such as Bax/caspases, interleukins, and chemokines. Likewise, it exerts central GABAergic, antidopaminergic, and anti-migraine functions and regulates sympathetic activity in a similar way to the drugs classically used in acute vestibular crisis. In this review, the role of melatonin as a potential treatment of the acute phase of vertigo is discussed.
Collapse
|
15
|
Schöpf CL, Ablinger C, Geisler SM, Stanika RI, Campiglio M, Kaufmann WA, Nimmervoll B, Schlick B, Brockhaus J, Missler M, Shigemoto R, Obermair GJ. Presynaptic α 2δ subunits are key organizers of glutamatergic synapses. Proc Natl Acad Sci U S A 2021; 118:e1920827118. [PMID: 33782113 PMCID: PMC8040823 DOI: 10.1073/pnas.1920827118] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
In nerve cells the genes encoding for α2δ subunits of voltage-gated calcium channels have been linked to synaptic functions and neurological disease. Here we show that α2δ subunits are essential for the formation and organization of glutamatergic synapses. Using a cellular α2δ subunit triple-knockout/knockdown model, we demonstrate a failure in presynaptic differentiation evidenced by defective presynaptic calcium channel clustering and calcium influx, smaller presynaptic active zones, and a strongly reduced accumulation of presynaptic vesicle-associated proteins (synapsin and vGLUT). The presynaptic defect is associated with the downscaling of postsynaptic AMPA receptors and the postsynaptic density. The role of α2δ isoforms as synaptic organizers is highly redundant, as each individual α2δ isoform can rescue presynaptic calcium channel trafficking and expression of synaptic proteins. Moreover, α2δ-2 and α2δ-3 with mutated metal ion-dependent adhesion sites can fully rescue presynaptic synapsin expression but only partially calcium channel trafficking, suggesting that the regulatory role of α2δ subunits is independent from its role as a calcium channel subunit. Our findings influence the current view on excitatory synapse formation. First, our study suggests that postsynaptic differentiation is secondary to presynaptic differentiation. Second, the dependence of presynaptic differentiation on α2δ implicates α2δ subunits as potential nucleation points for the organization of synapses. Finally, our results suggest that α2δ subunits act as transsynaptic organizers of glutamatergic synapses, thereby aligning the synaptic active zone with the postsynaptic density.
Collapse
Affiliation(s)
- Clemens L Schöpf
- Institute of Physiology, Medical University of Innsbruck, A-6020 Innsbruck, Austria
| | - Cornelia Ablinger
- Institute of Physiology, Medical University of Innsbruck, A-6020 Innsbruck, Austria
| | - Stefanie M Geisler
- Institute of Physiology, Medical University of Innsbruck, A-6020 Innsbruck, Austria
- Department of Pharmacology and Toxicology, University of Innsbruck, A-6020 Innsbruck, Austria
| | - Ruslan I Stanika
- Division of Physiology, Karl Landsteiner University of Health Sciences, A-3500 Krems, Austria
| | - Marta Campiglio
- Institute of Physiology, Medical University of Innsbruck, A-6020 Innsbruck, Austria
| | - Walter A Kaufmann
- Institute of Science and Technology Austria, A-3400 Klosterneuburg, Austria
| | - Benedikt Nimmervoll
- Institute of Physiology, Medical University of Innsbruck, A-6020 Innsbruck, Austria
| | - Bettina Schlick
- Institute of Physiology, Medical University of Innsbruck, A-6020 Innsbruck, Austria
| | - Johannes Brockhaus
- Institute of Anatomy and Molecular Neurobiology, Westfälische Wilhelms University, 48149 Münster, Germany
| | - Markus Missler
- Institute of Anatomy and Molecular Neurobiology, Westfälische Wilhelms University, 48149 Münster, Germany
| | - Ryuichi Shigemoto
- Institute of Science and Technology Austria, A-3400 Klosterneuburg, Austria
| | - Gerald J Obermair
- Institute of Physiology, Medical University of Innsbruck, A-6020 Innsbruck, Austria;
- Division of Physiology, Karl Landsteiner University of Health Sciences, A-3500 Krems, Austria
| |
Collapse
|
16
|
Geisler SM, Benedetti A, Schöpf CL, Schwarzer C, Stefanova N, Schwartz A, Obermair GJ. Phenotypic Characterization and Brain Structure Analysis of Calcium Channel Subunit α 2δ-2 Mutant (Ducky) and α 2δ Double Knockout Mice. Front Synaptic Neurosci 2021; 13:634412. [PMID: 33679366 PMCID: PMC7933509 DOI: 10.3389/fnsyn.2021.634412] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2020] [Accepted: 01/11/2021] [Indexed: 01/19/2023] Open
Abstract
Auxiliary α2δ subunits of voltage-gated calcium channels modulate channel trafficking, current properties, and synapse formation. Three of the four isoforms (α2δ-1, α2δ-2, and α2δ-3) are abundantly expressed in the brain; however, of the available knockout models, only α2δ-2 knockout or mutant mice display an obvious abnormal neurological phenotype. Thus, we hypothesize that the neuronal α2δ isoforms may have partially specific as well as redundant functions. To address this, we generated three distinct α2δ double knockout mouse models by crossbreeding single knockout (α2δ-1 and -3) or mutant (α2δ-2/ducky) mice. Here, we provide a first phenotypic description and brain structure analysis. We found that genotypic distribution of neonatal litters in distinct α2δ-1/-2, α2δ-1/-3, and α2δ-2/-3 breeding combinations did not conform to Mendel's law, suggesting premature lethality of single and double knockout mice. Notably, high occurrences of infant mortality correlated with the absence of specific α2δ isoforms (α2Δ-2 > α2δ-1 > α2δ-3), and was particularly observed in cages with behaviorally abnormal parenting animals of α2δ-2/-3 cross-breedings. Juvenile α2δ-1/-2 and α2δ-2/-3 double knockout mice displayed a waddling gate similar to ducky mice. However, in contrast to ducky and α2δ-1/-3 double knockout animals, α2δ-1/-2 and α2δ-2/-3 double knockout mice showed a more severe disease progression and highly impaired development. The observed phenotypes within the individual mouse lines may be linked to differences in the volume of specific brain regions. Reduced cortical volume in ducky mice, for example, was associated with a progressively decreased space between neurons, suggesting a reduction of total synaptic connections. Taken together, our findings show that α2δ subunits differentially regulate premature survival, postnatal growth, brain development, and behavior, suggesting specific neuronal functions in health and disease.
Collapse
Affiliation(s)
- Stefanie M. Geisler
- Institute of Physiology, Medical University Innsbruck, Innsbruck, Austria
- Department of Pharmacology and Toxicology, Center for Molecular Biosciences, University of Innsbruck, Innsbruck, Austria
| | - Ariane Benedetti
- Institute of Physiology, Medical University Innsbruck, Innsbruck, Austria
| | - Clemens L. Schöpf
- Institute of Physiology, Medical University Innsbruck, Innsbruck, Austria
| | - Christoph Schwarzer
- Department of Pharmacology, Medical University Innsbruck, Innsbruck, Austria
| | - Nadia Stefanova
- Division of Neurobiology, Department of Neurology, Medical University Innsbruck, Innsbruck, Austria
| | - Arnold Schwartz
- Department of Pharmacology and Systems Physiology, College of Medicine, University of Cincinnati, Cincinnati, OH, United States
| | - Gerald J. Obermair
- Institute of Physiology, Medical University Innsbruck, Innsbruck, Austria
- Division Physiology, Karl Landsteiner University of Health Sciences, Krems an der Donau, Austria
| |
Collapse
|
17
|
Dolphin AC. Functions of Presynaptic Voltage-gated Calcium Channels. FUNCTION (OXFORD, ENGLAND) 2020; 2:zqaa027. [PMID: 33313507 PMCID: PMC7709543 DOI: 10.1093/function/zqaa027] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/25/2020] [Revised: 10/16/2020] [Accepted: 10/20/2020] [Indexed: 01/06/2023]
Abstract
Voltage-gated calcium channels are the principal conduits for depolarization-mediated Ca2+ entry into excitable cells. In this review, the biophysical properties of the relevant members of this family of channels, those that are present in presynaptic terminals, will be discussed in relation to their function in mediating neurotransmitter release. Voltage-gated calcium channels have properties that ensure they are specialized for particular roles, for example, differences in their activation voltage threshold, their various kinetic properties, and their voltage-dependence of inactivation. All these attributes play into the ability of the various voltage-gated calcium channels to participate in different patterns of presynaptic vesicular release. These include synaptic transmission resulting from single action potentials, and longer-term changes mediated by bursts or trains of action potentials, as well as release resulting from graded changes in membrane potential in specialized sensory synapses.
Collapse
Affiliation(s)
- Annette C Dolphin
- Department of Neuroscience, Physiology and Pharmacology, University College London, WC1E 6BT, UK,Address correspondence to A.C.D. (e-mail: )
| |
Collapse
|
18
|
Ablinger C, Geisler SM, Stanika RI, Klein CT, Obermair GJ. Neuronal α 2δ proteins and brain disorders. Pflugers Arch 2020; 472:845-863. [PMID: 32607809 PMCID: PMC7351808 DOI: 10.1007/s00424-020-02420-2] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2020] [Revised: 06/08/2020] [Accepted: 06/12/2020] [Indexed: 01/31/2023]
Abstract
α2δ proteins are membrane-anchored extracellular glycoproteins which are abundantly expressed in the brain and the peripheral nervous system. They serve as regulatory subunits of voltage-gated calcium channels and, particularly in nerve cells, regulate presynaptic and postsynaptic functions independently from their role as channel subunits. α2δ proteins are the targets of the widely prescribed anti-epileptic and anti-allodynic drugs gabapentin and pregabalin, particularly for the treatment of neuropathic pain conditions. Recently, the human genes (CACNA2D1-4) encoding for the four known α2δ proteins (isoforms α2δ-1 to α2δ-4) have been linked to a large variety of neurological and neuropsychiatric disorders including epilepsy, autism spectrum disorders, bipolar disorders, schizophrenia, and depressive disorders. Here, we provide an overview of the hitherto identified disease associations of all known α2δ genes, hypothesize on the pathophysiological mechanisms considering their known physiological roles, and discuss the most immanent future research questions. Elucidating their specific physiological and pathophysiological mechanisms may open the way for developing entirely novel therapeutic paradigms for treating brain disorders.
Collapse
Affiliation(s)
- Cornelia Ablinger
- Institute of Physiology, Medical University Innsbruck, 6020, Innsbruck, Austria
| | - Stefanie M Geisler
- Department of Pharmacology and Toxicology, University of Innsbruck, 6020, Innsbruck, Austria
| | - Ruslan I Stanika
- Division Physiology, Karl Landsteiner University of Health Sciences, 3500, Krems, Austria
| | - Christian T Klein
- Department of Life Sciences, IMC University of Applied Sciences, 3500, Krems, Austria
| | - Gerald J Obermair
- Institute of Physiology, Medical University Innsbruck, 6020, Innsbruck, Austria.
- Division Physiology, Karl Landsteiner University of Health Sciences, 3500, Krems, Austria.
| |
Collapse
|
19
|
Kiyoshi C, Tedeschi A. Axon growth and synaptic function: A balancing act for axonal regeneration and neuronal circuit formation in CNS trauma and disease. Dev Neurobiol 2020; 80:277-301. [PMID: 32902152 PMCID: PMC7754183 DOI: 10.1002/dneu.22780] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2020] [Revised: 08/29/2020] [Accepted: 08/31/2020] [Indexed: 12/13/2022]
Abstract
Axons in the adult mammalian central nervous system (CNS) fail to regenerate inside out due to intrinsic and extrinsic neuronal determinants. During CNS development, axon growth, synapse formation, and function are tightly regulated processes allowing immature neurons to effectively grow an axon, navigate toward target areas, form synaptic contacts and become part of information processing networks that control behavior in adulthood. Not only immature neurons are able to precisely control the expression of a plethora of genes necessary for axon extension and pathfinding, synapse formation and function, but also non-neuronal cells such as astrocytes and microglia actively participate in sculpting the nervous system through refinement, consolidation, and elimination of synaptic contacts. Recent evidence indicates that a balancing act between axon regeneration and synaptic function may be crucial for rebuilding functional neuronal circuits after CNS trauma and disease in adulthood. Here, we review the role of classical and new intrinsic and extrinsic neuronal determinants in the context of CNS development, injury, and disease. Moreover, we discuss strategies targeting neuronal and non-neuronal cell behaviors, either alone or in combination, to promote axon regeneration and neuronal circuit formation in adulthood.
Collapse
Affiliation(s)
- Conrad Kiyoshi
- Department of Neuroscience, Wexner Medical Center, The Ohio State University, Columbus, OH 43210, USA
| | - Andrea Tedeschi
- Department of Neuroscience, Wexner Medical Center, The Ohio State University, Columbus, OH 43210, USA
- Discovery Theme on Chronic Brain Injury, The Ohio State University, Columbus, OH 43210, USA
| |
Collapse
|
20
|
Risher WC, Eroglu C. Emerging roles for α2δ subunits in calcium channel function and synaptic connectivity. Curr Opin Neurobiol 2020; 63:162-169. [PMID: 32521436 DOI: 10.1016/j.conb.2020.04.007] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2020] [Accepted: 04/29/2020] [Indexed: 12/17/2022]
Abstract
Central nervous system function requires the proper formation and function of synapses. The α2δ auxiliary subunits of voltage-gated calcium channels have emerged as regulators of a number of critical events associated with regulation of synaptic function, including channel trafficking and localization, as well as the initial establishment of synaptic structures. In this review, we will discuss some of these recent studies which have uncovered novel mechanisms for α2δ function at the synapse, including the regulation of calcium channel α1 subunit specificity and the promotion of dendritic spine growth. Moreover, we will cover recent advances that have been made in understanding the consequences of aberrant α2δ signaling in injury and disease.
Collapse
Affiliation(s)
- William Christopher Risher
- Department of Biomedical Sciences, Joan C. Edwards School of Medicine at Marshall University, Huntington, WV 25705, United States.
| | - Cagla Eroglu
- Department of Cell Biology, Duke University Medical Center, Durham, NC 27710, United States; Department of Neurobiology, Duke University Medical Center, Durham, NC 27710, United States; Duke Institute for Brain Sciences (DIBS), Durham, NC 27710, United States; Regeneration Next Initiative, Duke University, Durham, NC 27710, United States
| |
Collapse
|
21
|
Selected Ionotropic Receptors and Voltage-Gated Ion Channels: More Functional Competence for Human Induced Pluripotent Stem Cell (iPSC)-Derived Nociceptors. Brain Sci 2020; 10:brainsci10060344. [PMID: 32503260 PMCID: PMC7348931 DOI: 10.3390/brainsci10060344] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2020] [Revised: 05/28/2020] [Accepted: 05/30/2020] [Indexed: 01/09/2023] Open
Abstract
Preclinical research using different rodent model systems has largely contributed to the scientific progress in the pain field, however, it suffers from interspecies differences, limited access to human models, and ethical concerns. Human induced pluripotent stem cells (iPSCs) offer major advantages over animal models, i.e., they retain the genome of the donor (patient), and thus allow donor-specific and cell-type specific research. Consequently, human iPSC-derived nociceptors (iDNs) offer intriguingly new possibilities for patient-specific, animal-free research. In the present study, we characterized iDNs based on the expression of well described nociceptive markers and ion channels, and we conducted a side-by-side comparison of iDNs with mouse sensory neurons. Specifically, immunofluorescence (IF) analyses with selected markers including early somatosensory transcription factors (BRN3A/ISL1/RUNX1), the low-affinity nerve growth factor receptor (p75), hyperpolarization-activated cyclic nucleotide-gated channels (HCN), as well as high voltage-gated calcium channels (VGCC) of the CaV2 type, calcium permeable TRPV1 channels, and ionotropic GABAA receptors, were used to address the characteristics of the iDN phenotype. We further combined IF analyses with microfluorimetric Ca2+ measurements to address the functionality of these ion channels in iDNs. Thus, we provide a detailed morphological and functional characterization of iDNs, thereby, underpinning their enormous potential as an animal-free alternative for human specific research in the pain field for unveiling pathophysiological mechanisms and for unbiased, disease-specific personalized drug development.
Collapse
|
22
|
Taylor CP, Harris EW. Analgesia with Gabapentin and Pregabalin May Involve N-Methyl-d-Aspartate Receptors, Neurexins, and Thrombospondins. J Pharmacol Exp Ther 2020; 374:161-174. [DOI: 10.1124/jpet.120.266056] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2020] [Accepted: 04/17/2020] [Indexed: 11/22/2022] Open
|
23
|
Alles SRA, Cain SM, Snutch TP. Pregabalin as a Pain Therapeutic: Beyond Calcium Channels. Front Cell Neurosci 2020; 14:83. [PMID: 32351366 PMCID: PMC7174704 DOI: 10.3389/fncel.2020.00083] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2020] [Accepted: 03/20/2020] [Indexed: 12/12/2022] Open
Abstract
Initially developed to generate new treatments for epilepsy, gabapentin, and pregabalin (“gabapentinoids”) were engineered to mimic the action of GABA and to modulate GABA metabolism. Rather than their intended pharmacological action on GABA neurotransmission, instead, they exhibit a high affinity for the α2δ-1 and α2δ-2 subunits of voltage-activated calcium channels, wherein binding of gabapentinoids inhibits cellular calcium influx and attenuates neurotransmission. Despite a lack of activity on GABA levels, gabapentin and pregabalin are effective at suppressing seizures and subsequently approved as a new class of antiepileptic therapy for partial-onset epilepsy. Through the same hypothesized molecular mechanism and by controlling neuronal hyperexcitability, gabapentinoids demonstrate clear efficacy in pain management, which has arguably been their most extensively prescribed application to date. In this review, we focus on pregabalin as a second-generation gabapentinoid widely employed in the treatment of a variety of pain conditions. We also discuss the wider functional roles of α2δ subunits and the contributions that pregabalin might play in affecting physiological and pathophysiological processes.
Collapse
Affiliation(s)
- Sascha R A Alles
- Michael Smith Laboratories, University of British Columbia, Vancouver, BC, Canada.,Djavad Mowafaghian Center for Brain Health, University of British Columbia, Vancouver, BC, Canada.,Department of Anesthesiology and Critical Care Medicine, University of New Mexico School of Medicine, Albuquerque, NM, United States
| | - Stuart M Cain
- Michael Smith Laboratories, University of British Columbia, Vancouver, BC, Canada.,Djavad Mowafaghian Center for Brain Health, University of British Columbia, Vancouver, BC, Canada
| | - Terrance P Snutch
- Michael Smith Laboratories, University of British Columbia, Vancouver, BC, Canada.,Djavad Mowafaghian Center for Brain Health, University of British Columbia, Vancouver, BC, Canada
| |
Collapse
|
24
|
Dolphin AC, Lee A. Presynaptic calcium channels: specialized control of synaptic neurotransmitter release. Nat Rev Neurosci 2020; 21:213-229. [PMID: 32161339 PMCID: PMC7873717 DOI: 10.1038/s41583-020-0278-2] [Citation(s) in RCA: 98] [Impact Index Per Article: 24.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/12/2020] [Indexed: 11/09/2022]
Abstract
Chemical synapses are heterogeneous junctions formed between neurons that are specialized for the conversion of electrical impulses into the exocytotic release of neurotransmitters. Voltage-gated Ca2+ channels play a pivotal role in this process as they are the major conduits for the Ca2+ ions that trigger the fusion of neurotransmitter-containing vesicles with the presynaptic membrane. Alterations in the intrinsic function of these channels and their positioning within the active zone can profoundly alter the timing and strength of synaptic output. Advances in optical and electron microscopic imaging, structural biology and molecular techniques have facilitated recent breakthroughs in our understanding of the properties of voltage-gated Ca2+ channels that support their presynaptic functions. Here we examine the nature of these channels, how they are trafficked to and anchored within presynaptic boutons, and the mechanisms that allow them to function optimally in shaping the flow of information through neural circuits.
Collapse
Affiliation(s)
- Annette C Dolphin
- Department of Neuroscience, Physiology and Pharmacology, University College London, London, UK.
| | - Amy Lee
- Department of Molecular Physiology and Biophysics, University of Iowa, Iowa City, IA, USA.
| |
Collapse
|
25
|
Coste de Bagneaux P, von Elsner L, Bierhals T, Campiglio M, Johannsen J, Obermair GJ, Hempel M, Flucher BE, Kutsche K. A homozygous missense variant in CACNB4 encoding the auxiliary calcium channel beta4 subunit causes a severe neurodevelopmental disorder and impairs channel and non-channel functions. PLoS Genet 2020; 16:e1008625. [PMID: 32176688 PMCID: PMC7176149 DOI: 10.1371/journal.pgen.1008625] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2019] [Revised: 04/22/2020] [Accepted: 01/23/2020] [Indexed: 12/27/2022] Open
Abstract
P/Q-type channels are the principal presynaptic calcium channels in brain functioning in neurotransmitter release. They are composed of the pore-forming CaV2.1 α1 subunit and the auxiliary α2δ-2 and β4 subunits. β4 is encoded by CACNB4, and its multiple splice variants serve isoform-specific functions as channel subunits and transcriptional regulators in the nucleus. In two siblings with intellectual disability, psychomotor retardation, blindness, epilepsy, movement disorder and cerebellar atrophy we identified rare homozygous variants in the genes LTBP1, EMILIN1, CACNB4, MINAR1, DHX38 and MYO15 by whole-exome sequencing. In silico tools, animal model, clinical, and genetic data suggest the p.(Leu126Pro) CACNB4 variant to be likely pathogenic. To investigate the functional consequences of the CACNB4 variant, we introduced the corresponding mutation L125P into rat β4b cDNA. Heterologously expressed wild-type β4b associated with GFP-CaV1.2 and accumulated in presynaptic boutons of cultured hippocampal neurons. In contrast, the β4b-L125P mutant failed to incorporate into calcium channel complexes and to cluster presynaptically. When co-expressed with CaV2.1 in tsA201 cells, β4b and β4b-L125P augmented the calcium current amplitudes, however, β4b-L125P failed to stably complex with α1 subunits. These results indicate that p.Leu125Pro disrupts the stable association of β4b with native calcium channel complexes, whereas membrane incorporation, modulation of current density and activation properties of heterologously expressed channels remained intact. Wildtype β4b was specifically targeted to the nuclei of quiescent excitatory cells. Importantly, the p.Leu125Pro mutation abolished nuclear targeting of β4b in cultured myotubes and hippocampal neurons. While binding of β4b to the known interaction partner PPP2R5D (B56δ) was not affected by the mutation, complex formation between β4b-L125P and the neuronal TRAF2 and NCK interacting kinase (TNIK) seemed to be disturbed. In summary, our data suggest that the homozygous CACNB4 p.(Leu126Pro) variant underlies the severe neurological phenotype in the two siblings, most likely by impairing both channel and non-channel functions of β4b.
Collapse
Affiliation(s)
| | - Leonie von Elsner
- Institute of Human Genetics, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Tatjana Bierhals
- Institute of Human Genetics, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Marta Campiglio
- Department of Physiology and Medical Physics, Medical University Innsbruck, Innsbruck, Austria
| | - Jessika Johannsen
- Childrens Hospital, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Gerald J. Obermair
- Department of Physiology and Medical Physics, Medical University Innsbruck, Innsbruck, Austria
- Division Physiology, Karl Landsteiner University of Health Sciences, Krems, Austria
| | - Maja Hempel
- Institute of Human Genetics, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Bernhard E. Flucher
- Department of Physiology and Medical Physics, Medical University Innsbruck, Innsbruck, Austria
| | - Kerstin Kutsche
- Institute of Human Genetics, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| |
Collapse
|
26
|
α2δ-2 Protein Controls Structure and Function at the Cerebellar Climbing Fiber Synapse. J Neurosci 2020; 40:2403-2415. [PMID: 32086258 DOI: 10.1523/jneurosci.1514-19.2020] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2019] [Revised: 12/18/2019] [Accepted: 01/07/2020] [Indexed: 12/14/2022] Open
Abstract
α2δ proteins (Cacna2d1-4) are auxiliary subunits of voltage-dependent calcium channels that also drive synapse formation and maturation. Because cerebellar Purkinje cells (PCs) predominantly, if not exclusively, express one isoform of this family, α2δ-2 (Cacna2d2), we used PCs as a model system to examine roles of α2δ in excitatory synaptic function in male and female Cacna2d2 knock-out (KO) mice. Whole-cell recordings of PCs from acute cerebellar slices revealed altered climbing fiber (CF)-evoked complex spike generation, as well as increased amplitude and faster decay of CF-evoked EPSCs. CF terminals in the KO were localized more proximally on PC dendrites, as indicated by VGLUT2+ immunoreactive puncta, and computational modeling demonstrated that the increased EPSC amplitude can be partly attributed to the more proximal location of CF terminals. In addition, CFs in KO mice exhibited increased multivesicular transmission, corresponding to greater sustained responses during repetitive stimulation, despite a reduction in the measured probability of release. Electron microscopy demonstrated that mutant CF terminals had twice as many vesicle release sites, providing a morphologic explanation for the enhanced glutamate release. Though KO CFs evoked larger amplitude EPSCs, the charge transfer was the same as wild-type as a result of increased glutamate reuptake, producing faster decay kinetics. Together, the larger, faster EPSCs in the KO explain the altered complex spike responses, which degrade information transfer from PCs and likely contribute to ataxia in Cacna2d2 KO mice. Our results also illustrate the multidimensional synaptic roles of α2δ proteins.SIGNIFICANCE STATEMENT α2δ proteins (Cacna2d1-4) regulate synaptic transmission and synaptogenesis, but coexpression of multiple α2δ isoforms has obscured a clear understanding of how various α2δ proteins control synaptic function. We focused on roles of the α2δ-2 protein (Cacna2d2), the deletion of which causes cerebellar ataxia and epilepsy in mice and humans. Because cerebellar Purkinje cells (PCs) only express this single isoform, we studied excitatory climbing fiber synaptic function onto PCs in Cacna2d2 KO mice. Using optical and electrophysiological analysis, we provide a detailed description of the changes in PCs lacking α2δ-2, and provide a comprehensive mechanistic explanation for how functional synaptic phenotypes contribute to the altered cerebellar output.
Collapse
|
27
|
Hoover KM, Gratz SJ, Qi N, Herrmann KA, Liu Y, Perry-Richardson JJ, Vanderzalm PJ, O'Connor-Giles KM, Broihier HT. The calcium channel subunit α 2δ-3 organizes synapses via an activity-dependent and autocrine BMP signaling pathway. Nat Commun 2019; 10:5575. [PMID: 31811118 PMCID: PMC6898181 DOI: 10.1038/s41467-019-13165-7] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2019] [Accepted: 10/23/2019] [Indexed: 12/17/2022] Open
Abstract
Synapses are highly specialized for neurotransmitter signaling, yet activity-dependent growth factor release also plays critical roles at synapses. While efficient neurotransmitter signaling relies on precise apposition of release sites and neurotransmitter receptors, molecular mechanisms enabling high-fidelity growth factor signaling within the synaptic microenvironment remain obscure. Here we show that the auxiliary calcium channel subunit α2δ-3 promotes the function of an activity-dependent autocrine Bone Morphogenetic Protein (BMP) signaling pathway at the Drosophila neuromuscular junction (NMJ). α2δ proteins have conserved synaptogenic activity, although how they execute this function has remained elusive. We find that α2δ-3 provides an extracellular scaffold for an autocrine BMP signal, suggesting a mechanistic framework for understanding α2δ's conserved role in synapse organization. We further establish a transcriptional requirement for activity-dependent, autocrine BMP signaling in determining synapse density, structure, and function. We propose that activity-dependent, autocrine signals provide neurons with continuous feedback on their activity state for modulating both synapse structure and function.
Collapse
Affiliation(s)
- Kendall M Hoover
- Department of Neurosciences, Case Western Reserve University School of Medicine, Cleveland, OH, 44106, USA
| | - Scott J Gratz
- Department of Neuroscience, Brown University, Providence, RI, 02912, USA
| | - Nova Qi
- Department of Neurosciences, Case Western Reserve University School of Medicine, Cleveland, OH, 44106, USA
| | - Kelsey A Herrmann
- Department of Neurosciences, Case Western Reserve University School of Medicine, Cleveland, OH, 44106, USA
| | - Yizhou Liu
- Department of Neurosciences, Case Western Reserve University School of Medicine, Cleveland, OH, 44106, USA
| | - Jahci J Perry-Richardson
- Department of Neurosciences, Case Western Reserve University School of Medicine, Cleveland, OH, 44106, USA
| | - Pamela J Vanderzalm
- Department of Biology, John Carroll University, University Heights, OH, 44118, USA
| | | | - Heather T Broihier
- Department of Neurosciences, Case Western Reserve University School of Medicine, Cleveland, OH, 44106, USA.
| |
Collapse
|
28
|
Yang G, Shcheglovitov A. Probing disrupted neurodevelopment in autism using human stem cell-derived neurons and organoids: An outlook into future diagnostics and drug development. Dev Dyn 2019; 249:6-33. [PMID: 31398277 DOI: 10.1002/dvdy.100] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2019] [Revised: 07/23/2019] [Accepted: 07/31/2019] [Indexed: 12/11/2022] Open
Abstract
Autism spectrum disorders (ASDs) represent a spectrum of neurodevelopmental disorders characterized by impaired social interaction, repetitive or restrictive behaviors, and problems with speech. According to a recent report by the Centers for Disease Control and Prevention, one in 68 children in the US is diagnosed with ASDs. Although ASD-related diagnostics and the knowledge of ASD-associated genetic abnormalities have improved in recent years, our understanding of the cellular and molecular pathways disrupted in ASD remains very limited. As a result, no specific therapies or medications are available for individuals with ASDs. In this review, we describe the neurodevelopmental processes that are likely affected in the brains of individuals with ASDs and discuss how patient-specific stem cell-derived neurons and organoids can be used for investigating these processes at the cellular and molecular levels. Finally, we propose a discovery pipeline to be used in the future for identifying the cellular and molecular deficits and developing novel personalized therapies for individuals with idiopathic ASDs.
Collapse
Affiliation(s)
- Guang Yang
- Department of Neurobiology and Anatomy, University of Utah, Salt Lake City, Utah.,Neuroscience Graduate Program, University of Utah, Salt Lake City, Utah
| | - Alex Shcheglovitov
- Department of Neurobiology and Anatomy, University of Utah, Salt Lake City, Utah.,Neuroscience Graduate Program, University of Utah, Salt Lake City, Utah
| |
Collapse
|
29
|
Andrade A, Brennecke A, Mallat S, Brown J, Gomez-Rivadeneira J, Czepiel N, Londrigan L. Genetic Associations between Voltage-Gated Calcium Channels and Psychiatric Disorders. Int J Mol Sci 2019; 20:E3537. [PMID: 31331039 PMCID: PMC6679227 DOI: 10.3390/ijms20143537] [Citation(s) in RCA: 40] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2019] [Revised: 07/12/2019] [Accepted: 07/13/2019] [Indexed: 12/23/2022] Open
Abstract
Psychiatric disorders are mental, behavioral or emotional disorders. These conditions are prevalent, one in four adults suffer from any type of psychiatric disorders world-wide. It has always been observed that psychiatric disorders have a genetic component, however, new methods to sequence full genomes of large cohorts have identified with high precision genetic risk loci for these conditions. Psychiatric disorders include, but are not limited to, bipolar disorder, schizophrenia, autism spectrum disorder, anxiety disorders, major depressive disorder, and attention-deficit and hyperactivity disorder. Several risk loci for psychiatric disorders fall within genes that encode for voltage-gated calcium channels (CaVs). Calcium entering through CaVs is crucial for multiple neuronal processes. In this review, we will summarize recent findings that link CaVs and their auxiliary subunits to psychiatric disorders. First, we will provide a general overview of CaVs structure, classification, function, expression and pharmacology. Next, we will summarize tools to study risk loci associated with psychiatric disorders. We will examine functional studies of risk variations in CaV genes when available. Finally, we will review pharmacological evidence of the use of CaV modulators to treat psychiatric disorders. Our review will be of interest for those studying pathophysiological aspects of CaVs.
Collapse
Affiliation(s)
- Arturo Andrade
- Department of Biological Sciences, University of New Hampshire, Durham, NH 03824, USA.
| | - Ashton Brennecke
- Department of Biological Sciences, University of New Hampshire, Durham, NH 03824, USA
| | - Shayna Mallat
- Department of Biological Sciences, University of New Hampshire, Durham, NH 03824, USA
| | - Julian Brown
- Department of Biological Sciences, University of New Hampshire, Durham, NH 03824, USA
| | | | - Natalie Czepiel
- Department of Biological Sciences, University of New Hampshire, Durham, NH 03824, USA
| | - Laura Londrigan
- Department of Biological Sciences, University of New Hampshire, Durham, NH 03824, USA
| |
Collapse
|
30
|
Stephani F, Scheuer V, Eckrich T, Blum K, Wang W, Obermair GJ, Engel J. Deletion of the Ca 2+ Channel Subunit α 2δ3 Differentially Affects Ca v2.1 and Ca v2.2 Currents in Cultured Spiral Ganglion Neurons Before and After the Onset of Hearing. Front Cell Neurosci 2019; 13:278. [PMID: 31293392 PMCID: PMC6606706 DOI: 10.3389/fncel.2019.00278] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2019] [Accepted: 06/07/2019] [Indexed: 12/14/2022] Open
Abstract
Voltage-gated Ca2+ channels are composed of a pore-forming α1 subunit and auxiliary β and α2δ subunits, which modulate Ca2+ current properties and channel trafficking. So far, the partial redundancy and specificity of α1 for α2δ subunits in the CNS have remained largely elusive. Mature spiral ganglion (SG) neurons express α2δ subunit isoforms 1, 2, and 3 and multiple Ca2+ channel subtypes. Differentiation and in vivo functions of their endbulb of Held synapses, which rely on presynaptic P/Q channels (Lin et al., 2011), require the α2δ3 subunit (Pirone et al., 2014). This led us to hypothesize that P/Q channels may preferentially co-assemble with α2δ3. Using a dissociated primary culture, we analyzed the effects of α2δ3 deletion on somatic Ca2+ currents (ICa) of SG neurons isolated at postnatal day 20 (P20), when the cochlea is regarded to be mature. P/Q currents were the dominating steady-state Ca2+ currents (54% of total) followed by T-type, L-type, N-type, and R-type currents. Deletion of α2δ3 reduced P/Q- and R-type currents by 60 and 38%, respectively, whereas L-type, N-type, and T-type currents were not altered. A subset of ICa types was also analyzed in SG neurons isolated at P5, i.e., before the onset of hearing (P12). Both L-type and N-type current amplitudes of wildtype SG neurons were larger at P5 compared with P20. Deletion of α2δ3 reduced L-type and N-type currents by 23 and 44%, respectively. In contrast, small P/Q currents, which were just being up-regulated at P5, were unaffected by the lack of α2δ3. In summary, α2δ3 regulates amplitudes of L- and N-type currents of immature cultured SG neurons, whereas it regulates P/Q- and R-type currents at P20. Our data indicate a developmental switch from dominating somatic N- to P/Q-type currents in cultured SG neurons. A switch from N- to P/Q-type channels, which has been observed at several central synapses, may also occur at developing endbulbs of Held. In this case, reduction of both neonatal N- (P5) and more mature P/Q-type currents (around/after hearing onset) may contribute to the impaired morphology and function of endbulb synapses in α2δ3-deficient mice.
Collapse
Affiliation(s)
- Friederike Stephani
- Department of Biophysics, Center for Integrative Physiology and Molecular Medicine, School of Medicine, Saarland University, Homburg, Germany
| | - Veronika Scheuer
- Department of Biophysics, Center for Integrative Physiology and Molecular Medicine, School of Medicine, Saarland University, Homburg, Germany
| | - Tobias Eckrich
- Department of Biophysics, Center for Integrative Physiology and Molecular Medicine, School of Medicine, Saarland University, Homburg, Germany
| | - Kerstin Blum
- Department of Biophysics, Center for Integrative Physiology and Molecular Medicine, School of Medicine, Saarland University, Homburg, Germany
| | - Wenying Wang
- Department of Physiology, School of Medicine, University of Nevada, Reno, NV, United States
| | - Gerald J Obermair
- Department of Physiology and Medical Physics, Medical University Innsbruck, Innsbruck, Austria.,Division Physiology, Karl Landsteiner University of Health Sciences, Krems, Austria
| | - Jutta Engel
- Department of Biophysics, Center for Integrative Physiology and Molecular Medicine, School of Medicine, Saarland University, Homburg, Germany
| |
Collapse
|
31
|
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'.
Collapse
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
| |
Collapse
|