1
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Pelizzari S, Heiss MC, Fernández-Quintero ML, El Ghaleb Y, Liedl KR, Tuluc P, Campiglio M, Flucher BE. Ca V1.1 voltage-sensing domain III exclusively controls skeletal muscle excitation-contraction coupling. Nat Commun 2024; 15:7440. [PMID: 39198449 PMCID: PMC11358481 DOI: 10.1038/s41467-024-51809-5] [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: 12/04/2023] [Accepted: 08/16/2024] [Indexed: 09/01/2024] Open
Abstract
Skeletal muscle contractions are initiated by action potentials, which are sensed by the voltage-gated calcium channel (CaV1.1) and are conformationally coupled to calcium release from intracellular stores. Notably, CaV1.1 contains four separate voltage-sensing domains (VSDs), which activate channel gating and excitation-contraction (EC-) coupling at different voltages and with distinct kinetics. Here we show that a single VSD of CaV1.1 controls skeletal muscle EC-coupling. Whereas mutations in VSDs I, II and IV affect the current properties but not EC-coupling, only mutations in VSD III alter the voltage-dependence of depolarization-induced calcium release. Molecular dynamics simulations reveal comprehensive, non-canonical state transitions of VSD III in response to membrane depolarization. Identifying the voltage sensor that activates EC-coupling and detecting its unique conformational changes opens the door to unraveling the downstream events linking VSD III motion to the opening of the calcium release channel, and thus resolving the signal transduction mechanism of skeletal muscle EC-coupling.
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Affiliation(s)
- Simone Pelizzari
- Institute of Physiology, Department of Physiology and Medical Biophysics, Medical University Innsbruck, 6020, Innsbruck, Austria
| | - Martin C Heiss
- Institute of Physiology, Department of Physiology and Medical Biophysics, Medical University Innsbruck, 6020, Innsbruck, Austria
| | | | - Yousra El Ghaleb
- Institute of Physiology, Department of Physiology and Medical Biophysics, Medical University Innsbruck, 6020, Innsbruck, Austria
| | - Klaus R Liedl
- Institute of General, Inorganic and Theoretical Chemistry, University of Innsbruck, Innsbruck, Austria
| | - Petronel Tuluc
- Department of Pharmacology and Toxicology, Center for Molecular Biosciences Innsbruck, University of Innsbruck, 6020, Innsbruck, Austria
| | - Marta Campiglio
- Institute of Physiology, Department of Physiology and Medical Biophysics, Medical University Innsbruck, 6020, Innsbruck, Austria
| | - Bernhard E Flucher
- Institute of Physiology, Department of Physiology and Medical Biophysics, Medical University Innsbruck, 6020, Innsbruck, Austria.
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2
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Bibollet H, Kramer A, Bannister RA, Hernández-Ochoa EO. Advances in Ca V1.1 gating: New insights into permeation and voltage-sensing mechanisms. Channels (Austin) 2023; 17:2167569. [PMID: 36642864 PMCID: PMC9851209 DOI: 10.1080/19336950.2023.2167569] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2022] [Accepted: 01/09/2023] [Indexed: 01/17/2023] Open
Abstract
The CaV1.1 voltage-gated Ca2+ channel carries L-type Ca2+ current and is the voltage-sensor for excitation-contraction (EC) coupling in skeletal muscle. Significant breakthroughs in the EC coupling field have often been close on the heels of technological advancement. In particular, CaV1.1 was the first voltage-gated Ca2+ channel to be cloned, the first ion channel to have its gating current measured and the first ion channel to have an effectively null animal model. Though these innovations have provided invaluable information regarding how CaV1.1 detects changes in membrane potential and transmits intra- and inter-molecular signals which cause opening of the channel pore and support Ca2+ release from the sarcoplasmic reticulum remain elusive. Here, we review current perspectives on this topic including the recent application of functional site-directed fluorometry.
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Affiliation(s)
- Hugo Bibollet
- Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Audra Kramer
- Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Roger A. Bannister
- Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, Baltimore, MD, USA
- Department of Pathology, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Erick O. Hernández-Ochoa
- Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, Baltimore, MD, USA
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3
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Feng W, Lopez JR, Antrobus S, Zheng J, Uryash A, Dong Y, Beqollari D, Bannister RA, Hopkins PM, Beam KG, Allen PD, Pessah IN. Putative malignant hyperthermia mutation Ca V1.1-R174W is insufficient to trigger a fulminant response to halothane or confer heat stress intolerance. J Biol Chem 2023; 299:104992. [PMID: 37392848 PMCID: PMC10413282 DOI: 10.1016/j.jbc.2023.104992] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2023] [Revised: 06/16/2023] [Accepted: 06/20/2023] [Indexed: 07/03/2023] Open
Abstract
Malignant hyperthermia susceptibility (MHS) is an autosomal dominant pharmacogenetic disorder that manifests as a hypermetabolic state when carriers are exposed to halogenated volatile anesthetics or depolarizing muscle relaxants. In animals, heat stress intolerance is also observed. MHS is linked to over 40 variants in RYR1 that are classified as pathogenic for diagnostic purposes. More recently, a few rare variants linked to the MHS phenotype have been reported in CACNA1S, which encodes the voltage-activated Ca2+ channel CaV1.1 that conformationally couples to RyR1 in skeletal muscle. Here, we describe a knock-in mouse line that expresses one of these putative variants, CaV1.1-R174W. Heterozygous (HET) and homozygous (HOM) CaV1.1-R174W mice survive to adulthood without overt phenotype but fail to trigger with fulminant malignant hyperthermia when exposed to halothane or moderate heat stress. All three genotypes (WT, HET, and HOM) express similar levels of CaV1.1 by quantitative PCR, Western blot, [3H]PN200-110 receptor binding and immobilization-resistant charge movement densities in flexor digitorum brevis fibers. Although HOM fibers have negligible CaV1.1 current amplitudes, HET fibers have similar amplitudes to WT, suggesting a preferential accumulation of the CaV1.1-WT protein at triad junctions in HET animals. Never-the-less both HET and HOM have slightly elevated resting free Ca2+ and Na+ measured with double barreled microelectrode in vastus lateralis that is disproportional to upregulation of transient receptor potential canonical (TRPC) 3 and TRPC6 in skeletal muscle. CaV1.1-R174W and upregulation of TRPC3/6 alone are insufficient to trigger fulminant malignant hyperthermia response to halothane and/or heat stress in HET and HOM mice.
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Affiliation(s)
- Wei Feng
- Department of Molecular Biosciences, University of California Davis, Davis, California, USA
| | - Jose R Lopez
- Department of Molecular Biosciences, University of California Davis, Davis, California, USA; Department of Research, Mount Sinai Medical Center, Miami Beach, Florida, USA
| | - Shane Antrobus
- Department of Molecular Biosciences, University of California Davis, Davis, California, USA
| | - Jing Zheng
- Department of Molecular Biosciences, University of California Davis, Davis, California, USA
| | - Arkady Uryash
- Department of Research, Mount Sinai Medical Center, Miami Beach, Florida, USA
| | - Yao Dong
- Department of Molecular Biosciences, University of California Davis, Davis, California, USA
| | - Donald Beqollari
- Department of Medicine-Cardiology Division, University of Colorado Anschutz Medical Campus, Aurora, Colorado, USA
| | - Roger A Bannister
- Department of Medicine-Cardiology Division, University of Colorado Anschutz Medical Campus, Aurora, Colorado, USA
| | - Philip M Hopkins
- Institute of Medical Research at St James's, University of Leeds, Leeds, United Kingdom
| | - Kurt G Beam
- Department of Physiology and Biophysics, University of Colorado Anschutz Medical Campus, Aurora, Colorado, USA
| | - Paul D Allen
- Department of Molecular Biosciences, University of California Davis, Davis, California, USA; Institute of Medical Research at St James's, University of Leeds, Leeds, United Kingdom
| | - Isaac N Pessah
- Department of Molecular Biosciences, University of California Davis, Davis, California, USA.
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4
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Folacci M, Estaran S, Ménard C, Bertaud A, Rousset M, Roussel J, Thibaud JB, Vignes M, Chavanieu A, Charnet P, Cens T. Functional Characterization of Four Known Cav2.1 Variants Associated with Neurodevelopmental Disorders. MEMBRANES 2023; 13:96. [PMID: 36676903 PMCID: PMC9864995 DOI: 10.3390/membranes13010096] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/30/2022] [Revised: 01/06/2023] [Accepted: 01/09/2023] [Indexed: 06/17/2023]
Abstract
Cav2.1 channels are expressed throughout the brain and are the predominant Ca2+ channels in the Purkinje cells. These cerebellar neurons fire spontaneously, and Cav2.1 channels are involved in the regular pacemaking activity. The loss of precision of the firing pattern of Purkinje cells leads to ataxia, a disorder characterized by poor balance and difficulties in performing coordinated movements. In this study, we aimed at characterizing functional and structural consequences of four variations (p.A405T in I-II loop and p.R1359W, p.R1667W and p.S1799L in IIIS4, IVS4, and IVS6 helices, respectively) identified in patients exhibiting a wide spectrum of disorders including ataxia symptoms. Functional analysis using two major Cav2.1 splice variants (Cav2.1+e47 and Cav2.1-e47) in Xenopus laevis oocytes, revealed a lack of effect upon A405T substitution and a significant loss-of-function caused by R1359W, whereas R1667W and S1799L caused both channel gain-of-function and loss-of-function, in a splice variant-dependent manner. Structural analysis revealed the loss of interactions with S1, S2, and S3 helices upon R1359W and R1667W substitutions, but a lack of obvious structural changes with S1799L. Computational modeling suggests that biophysical changes induced by Cav2.1 pathogenic mutations might affect action potential frequency in Purkinje cells.
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5
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Campiglio M, Dyrda A, Tuinte WE, Török E. Ca V1.1 Calcium Channel Signaling Complexes in Excitation-Contraction Coupling: Insights from Channelopathies. Handb Exp Pharmacol 2023; 279:3-39. [PMID: 36592225 DOI: 10.1007/164_2022_627] [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: 01/03/2023]
Abstract
In skeletal muscle, excitation-contraction (EC) coupling relies on the mechanical coupling between two ion channels: the L-type voltage-gated calcium channel (CaV1.1), located in the sarcolemma and functioning as the voltage sensor of EC coupling, and the ryanodine receptor 1 (RyR1), located on the sarcoplasmic reticulum serving as the calcium release channel. To this day, the molecular mechanism by which these two ion channels are linked remains elusive. However, recently, skeletal muscle EC coupling could be reconstituted in heterologous cells, revealing that only four proteins are essential for this process: CaV1.1, RyR1, and the cytosolic proteins CaVβ1a and STAC3. Due to the crucial role of these proteins in skeletal muscle EC coupling, any mutation that affects any one of these proteins can have devastating consequences, resulting in congenital myopathies and other pathologies.Here, we summarize the current knowledge concerning these four essential proteins and discuss the pathophysiology of the CaV1.1, RyR1, and STAC3-related skeletal muscle diseases with an emphasis on the molecular mechanisms. Being part of the same signalosome, mutations in different proteins often result in congenital myopathies with similar symptoms or even in the same disease.
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Affiliation(s)
- Marta Campiglio
- Institute of Physiology, Medical University Innsbruck, Innsbruck, Austria.
| | - Agnieszka Dyrda
- Institute of Physiology, Medical University Innsbruck, Innsbruck, Austria
| | - Wietske E Tuinte
- Institute of Physiology, Medical University Innsbruck, Innsbruck, Austria
| | - Enikő Török
- Institute of Physiology, Medical University Innsbruck, Innsbruck, Austria
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Murayama T, Kurebayashi N, Numaga-Tomita T, Kobayashi T, Okazaki S, Yamashiro K, Nakada T, Mori S, Ishida R, Kagechika H, Yamada M, Sakurai T. A reconstituted depolarization-induced Ca2+ release platform for validation of skeletal muscle disease mutations and drug discovery. J Gen Physiol 2022; 154:213630. [PMID: 36318155 PMCID: PMC9629852 DOI: 10.1085/jgp.202213230] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2022] [Revised: 09/06/2022] [Accepted: 10/03/2022] [Indexed: 11/06/2022] Open
Abstract
In skeletal muscle excitation-contraction (E-C) coupling, depolarization of the plasma membrane triggers Ca2+ release from the sarcoplasmic reticulum (SR), referred to as depolarization-induced Ca2+ release (DICR). DICR occurs through the type 1 ryanodine receptor (RyR1), which physically interacts with the dihydropyridine receptor Cav1.1 subunit in specific machinery formed with additional essential components including β1a, Stac3 adaptor protein, and junctophilins. Exome sequencing has accelerated the discovery of many novel mutations in genes encoding DICR machinery in various skeletal muscle diseases. However, functional validation is time-consuming because it must be performed in a skeletal muscle environment. In this study, we established a platform of the reconstituted DICR in HEK293 cells. The essential components were effectively transduced into HEK293 cells expressing RyR1 using baculovirus vectors, and Ca2+ release was quantitatively measured with R-CEPIA1er, a fluorescent ER Ca2+ indicator, without contaminant of extracellular Ca2+ influx. In these cells, [K+]-dependent Ca2+ release was triggered by chemical depolarization with the aid of inward rectifying potassium channel, indicating a successful reconstitution of DICR. Using the platform, we evaluated several Cav1.1 mutations that are implicated in malignant hyperthermia and myopathy. We also tested several RyR1 inhibitors; whereas dantrolene and Cpd1 inhibited DICR, procaine had no effect. Furthermore, twitch potentiators such as perchlorate and thiocyanate shifted the voltage dependence of DICR to more negative potentials without affecting Ca2+-induced Ca2+ release. These results well reproduced the findings with the muscle fibers and the cultured myotubes. Since the procedure is simple and reproducible, the reconstituted DICR platform will be highly useful for the validation of mutations and drug discovery for skeletal muscle diseases.
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Affiliation(s)
- Takashi Murayama
- Department of Pharmacology, Juntendo University School of Medicine, Tokyo, Japan
| | - Nagomi Kurebayashi
- Department of Pharmacology, Juntendo University School of Medicine, Tokyo, Japan
| | - Takuro Numaga-Tomita
- Department of Molecular Pharmacology, Shinshu University School of Medicine, Matsumoto, Japan
| | - Takuya Kobayashi
- Department of Pharmacology, Juntendo University School of Medicine, Tokyo, Japan
| | - Satoru Okazaki
- Department of Pharmacology, Juntendo University School of Medicine, Tokyo, Japan
| | - Kyosuke Yamashiro
- Department of Pharmacology, Juntendo University School of Medicine, Tokyo, Japan
| | - Tsutomu Nakada
- Department of Molecular Pharmacology, Shinshu University School of Medicine, Matsumoto, Japan
| | - Shuichi Mori
- Institute of Biomaterials and Bioengineering, Tokyo Medical and Dental University, Tokyo, Japan
| | - Ryosuke Ishida
- Institute of Biomaterials and Bioengineering, Tokyo Medical and Dental University, Tokyo, Japan
| | - Hiroyuki Kagechika
- Institute of Biomaterials and Bioengineering, Tokyo Medical and Dental University, Tokyo, Japan
| | - Mitsuhiko Yamada
- Department of Molecular Pharmacology, Shinshu University School of Medicine, Matsumoto, Japan
| | - Takashi Sakurai
- Department of Pharmacology, Juntendo University School of Medicine, Tokyo, Japan
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7
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van den Bersselaar LR, Gubbels M, Riazi S, Heytens L, Jungbluth H, Voermans NC, Snoeck MMJ. Mapping the current evidence on the anesthetic management of adult patients with neuromuscular disorders-a scoping review. Can J Anaesth 2022; 69:756-773. [PMID: 35322378 PMCID: PMC9132812 DOI: 10.1007/s12630-022-02230-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2021] [Revised: 01/21/2022] [Accepted: 01/29/2022] [Indexed: 11/22/2022] Open
Abstract
PURPOSE Patients with neuromuscular disorders (NMDs) are at increased risk of perioperative complications. The objective of this scoping review was to examine emerging evidence from published studies, case reports, and review articles on anesthetic management of patients with NMDs, following the methodological frame for scoping reviews. SOURCES We searched PubMed and EMBASE for articles published between 1 January 2000 and 14 July 2021. PRINCIPAL FINDINGS Three prospective and 21 retrospective studies on altered pharmacokinetics and pharmacodynamics of neuromuscular blocking agents (NMBA) in NMD patients were included. Furthermore, 168 case reports/series reporting 212 anesthetics in 197 patients were included. These studies showed that preanesthetic neuromuscular monitoring can be used for precise NMBA dosing in myasthenia gravis patients. Sugammadex was associated with fewer postoperative myasthenic crises. Perioperative complications were not associated with specific anesthetic agents. Case reports/series showed that in 32% (67/212) of anesthetics, at least one complication was reported. Unexpected intensive care unit admission was a frequently reported complication. Patients with a complicated disease course may have had a higher use of succinylcholine (unadjusted relative risk, 0.13; 95% confidence interval [CI], 0.20 to 0.86) and volatile anesthetics (adjusted odds ratio [OR], 0.38; 95% CI, 0.20 to 0.73; P = 0.004). CONCLUSION Evidence on the anesthetic management and perioperative complications of patients with NMDs is mainly based on small retrospective studies and case reports. Further clinical trials or large retrospective studies are required to investigate the choice of safe anesthetic agents. Main areas of interest are the potential benefits of neuromuscular monitoring and sugammadex and the risks possibly associated with volatile anesthetics and succinylcholine.
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Affiliation(s)
- Luuk R van den Bersselaar
- Department of Anaesthesiology, Malignant Hyperthermia Investigation Unit, Canisius Wilhelmina Hospital, Nijmegen, The Netherlands.
- Department of Neurology, Cognition and Behaviour, Donders Institute for Brain, Radboud University Medical Center, Nijmegen, The Netherlands.
| | - Madelief Gubbels
- Department of Neurology, Cognition and Behaviour, Donders Institute for Brain, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Sheila Riazi
- Department of Anesthesiology and Pain Medicine, Malignant Hyperthermia Investigation Unit, University Health Network, University of Toronto, Toronto, ON, Canada
| | - Luc Heytens
- Malignant Hyperthermia Research Unit, University of Antwerp, Antwerp, Belgium
| | - Heinz Jungbluth
- Department of Paediatric Neurology, Neuromuscular Service, Evelina's Children Hospital, Guy's and St Thomas' Hospitals NHS Foundation Trust, London, UK
- Department of Basic and Clinical Neuroscience, IoPPN, King's College, London, UK
- Randall Division for Cell and Molecular Biophysics, Muscle Signalling Section, King's College, London, UK
| | - Nicol C Voermans
- Department of Neurology, Cognition and Behaviour, Donders Institute for Brain, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Marc M J Snoeck
- Department of Anaesthesiology, Malignant Hyperthermia Investigation Unit, Canisius Wilhelmina Hospital, Nijmegen, The Netherlands
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8
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van den Bersselaar LR, Riazi S, Snoeck M, Jungbluth H, Voermans NC. 259th ENMC international workshop: Anaesthesia and neuromuscular disorders 11 December, 2020 and 28-29 May, 2021. Neuromuscul Disord 2021; 32:86-97. [PMID: 34916120 DOI: 10.1016/j.nmd.2021.11.005] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2021] [Revised: 11/09/2021] [Accepted: 11/12/2021] [Indexed: 02/07/2023]
Affiliation(s)
- L R van den Bersselaar
- Department of Anaesthesiology, Malignant Hyperthermia Investigation Unit, Canisius Wilhelmina Hospital, Nijmegen, the Netherlands; Department of Neurology, Radboud University Medical Center, Reinier Postlaan 4, P.O. Box 9101, 6500 HB, Nijmegen 6525 GC, the Netherlands
| | - S Riazi
- Department of Anesthesiology and Pain Medicine, Malignant Hyperthermia Investigation Unit, University Health Network, University of Toronto, Toronto, Canada
| | - Mmj Snoeck
- Department of Anaesthesiology, Malignant Hyperthermia Investigation Unit, Canisius Wilhelmina Hospital, Nijmegen, the Netherlands
| | - H Jungbluth
- Department of Paediatric Neurology, Neuromuscular Service, Evelina's Children Hospital, Guy's and St Thomas' Hospitals NHS Foundation Trust, London, United Kingdom; Randall Centre for Cell and Molecular Biophysics, Muscle Signalling Section, Faculty of Life Sciences and Medicine, King's College London, London, United Kingdom
| | - N C Voermans
- Department of Neurology, Radboud University Medical Center, Reinier Postlaan 4, P.O. Box 9101, 6500 HB, Nijmegen 6525 GC, the Netherlands.
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9
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Short B. Distinct roles for CaV1.1's voltage-sensing domains. J Gen Physiol 2021; 153:212689. [PMID: 34623381 PMCID: PMC8563281 DOI: 10.1085/jgp.202113031] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022] Open
Abstract
Study reveals how a slowly activating calcium channel is able to control rapid excitation–contraction coupling in skeletal muscle.
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10
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Savalli N, Angelini M, Steccanella F, Wier J, Wu F, Quinonez M, DiFranco M, Neely A, Cannon SC, Olcese R. The distinct role of the four voltage sensors of the skeletal CaV1.1 channel in voltage-dependent activation. J Gen Physiol 2021; 153:212652. [PMID: 34546289 PMCID: PMC8460119 DOI: 10.1085/jgp.202112915] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2021] [Accepted: 08/22/2021] [Indexed: 11/30/2022] Open
Abstract
Initiation of skeletal muscle contraction is triggered by rapid activation of RYR1 channels in response to sarcolemmal depolarization. RYR1 is intracellular and has no voltage-sensing structures, but it is coupled with the voltage-sensing apparatus of CaV1.1 channels to inherit voltage sensitivity. Using an opto-electrophysiological approach, we resolved the excitation-driven molecular events controlling both CaV1.1 and RYR1 activations, reported as fluorescence changes. We discovered that each of the four human CaV1.1 voltage-sensing domains (VSDs) exhibits unique biophysical properties: VSD-I time-dependent properties were similar to ionic current activation kinetics, suggesting a critical role of this voltage sensor in CaV1.1 activation; VSD-II, VSD-III, and VSD-IV displayed faster activation, compatible with kinetics of sarcoplasmic reticulum Ca2+ release. The prominent role of VSD-I in governing CaV1.1 activation was also confirmed using a naturally occurring, charge-neutralizing mutation in VSD-I (R174W). This mutation abolished CaV1.1 current at physiological membrane potentials by impairing VSD-I activation without affecting the other VSDs. Using a structurally relevant allosteric model of CaV activation, which accounted for both time- and voltage-dependent properties of CaV1.1, to predict VSD-pore coupling energies, we found that VSD-I contributed the most energy (~75 meV or ∼3 kT) toward the stabilization of the open states of the channel, with smaller (VSD-IV) or negligible (VSDs II and III) energetic contribution from the other voltage sensors (<25 meV or ∼1 kT). This study settles the longstanding question of how CaV1.1, a slowly activating channel, can trigger RYR1 rapid activation, and reveals a new mechanism for voltage-dependent activation in ion channels, whereby pore opening of human CaV1.1 channels is primarily driven by the activation of one voltage sensor, a mechanism distinct from that of all other voltage-gated channels.
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Affiliation(s)
- Nicoletta Savalli
- Department of Anesthesiology and Perioperative Medicine, Division of Molecular Medicine, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA
| | - Marina Angelini
- Department of Anesthesiology and Perioperative Medicine, Division of Molecular Medicine, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA
| | - Federica Steccanella
- Department of Anesthesiology and Perioperative Medicine, Division of Molecular Medicine, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA
| | - Julian Wier
- Department of Anesthesiology and Perioperative Medicine, Division of Molecular Medicine, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA
| | - Fenfen Wu
- Department of Physiology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA
| | - Marbella Quinonez
- Department of Physiology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA
| | - Marino DiFranco
- Department of Physiology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA
| | - Alan Neely
- Department of Anesthesiology and Perioperative Medicine, Division of Molecular Medicine, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA.,Centro Interdisciplinario de Neurociencias de Valparaíso, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso, Chile
| | - Stephen C Cannon
- Department of Physiology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA
| | - Riccardo Olcese
- Department of Anesthesiology and Perioperative Medicine, Division of Molecular Medicine, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA.,Department of Physiology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA
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11
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Pathophysiological Effects of Overactive STIM1 on Murine Muscle Function and Structure. Cells 2021; 10:cells10071730. [PMID: 34359900 PMCID: PMC8304505 DOI: 10.3390/cells10071730] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2021] [Revised: 06/25/2021] [Accepted: 06/29/2021] [Indexed: 12/15/2022] Open
Abstract
Store-operated Ca2+ entry (SOCE) is a ubiquitous mechanism regulating extracellular Ca2+ entry to control a multitude of Ca2+-dependent signaling pathways and cellular processes. SOCE relies on the concerted activity of the reticular Ca2+ sensor STIM1 and the plasma membrane Ca2+ channel ORAI1, and dysfunctions of these key factors result in human pathologies. STIM1 and ORAI1 gain-of-function (GoF) mutations induce excessive Ca2+ influx through SOCE over-activation, and cause tubular aggregate myopathy (TAM) and Stormorken syndrome (STRMK), two overlapping disorders characterized by muscle weakness and additional multi-systemic signs affecting growth, platelets, spleen, skin, and intellectual abilities. In order to investigate the pathophysiological effect of overactive SOCE on muscle function and structure, we combined transcriptomics with morphological and functional studies on a TAM/STRMK mouse model. Muscles from Stim1R304W/+ mice displayed aberrant expression profiles of genes implicated in Ca2+ handling and excitation-contraction coupling (ECC), and in vivo investigations evidenced delayed muscle contraction and relaxation kinetics. We also identified signs of reticular stress and abnormal mitochondrial activity, and histological and respirometric analyses on muscle samples revealed enhanced myofiber degeneration associated with reduced mitochondrial respiration. Taken together, we uncovered a molecular disease signature and deciphered the pathomechanism underlying the functional and structural muscle anomalies characterizing TAM/STRMK.
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12
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Dayal A, Fernández-Quintero ML, Liedl KR, Grabner M. Pore mutation N617D in the skeletal muscle DHPR blocks Ca 2+ influx due to atypical high-affinity Ca 2+ binding. eLife 2021; 10:63435. [PMID: 34061024 PMCID: PMC8184209 DOI: 10.7554/elife.63435] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2020] [Accepted: 05/28/2021] [Indexed: 11/13/2022] Open
Abstract
Skeletal muscle excitation-contraction (EC) coupling roots in Ca2+-influx-independent inter-channel signaling between the sarcolemmal dihydropyridine receptor (DHPR) and the ryanodine receptor (RyR1) in the sarcoplasmic reticulum. Although DHPR Ca2+ influx is irrelevant for EC coupling, its putative role in other muscle-physiological and developmental pathways was recently examined using two distinct genetically engineered mouse models carrying Ca2+ non-conducting DHPRs: DHPR(N617D) (Dayal et al., 2017) and DHPR(E1014K) (Lee et al., 2015). Surprisingly, despite complete block of DHPR Ca2+-conductance, histological, biochemical, and physiological results obtained from these two models were contradictory. Here, we characterize the permeability and selectivity properties and henceforth the mechanism of Ca2+ non-conductance of DHPR(N617). Our results reveal that only mutant DHPR(N617D) with atypical high-affinity Ca2+ pore-binding is tight for physiologically relevant monovalent cations like Na+ and K+. Consequently, we propose a molecular model of cooperativity between two ion selectivity rings formed by negatively charged residues in the DHPR pore region.
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Affiliation(s)
- Anamika Dayal
- Department of Pharmacology, Medical University of Innsbruck, Innsbruck, Austria
| | | | - Klaus R Liedl
- Institute of General, Inorganic and Theoretical Chemistry, University of Innsbruck, Innsbruck, Austria
| | - Manfred Grabner
- Department of Pharmacology, Medical University of Innsbruck, Innsbruck, Austria
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Molecular Modification of Transient Receptor Potential Canonical 6 Channels Modulates Calcium Dyshomeostasis in a Mouse Model Relevant to Malignant Hyperthermia. Anesthesiology 2021; 134:234-247. [PMID: 33301562 PMCID: PMC9836077 DOI: 10.1097/aln.0000000000003635] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
BACKGROUND Pharmacologic modulation has previously shown that transient receptor potential canonical (TRPC) channels play an important role in the pathogenesis of malignant hyperthermia. This study tested the hypothesis that genetically suppressing the function of TRPC6 can partially ameliorate muscle cation dyshomeostasis and the response to halothane in a mouse model relevant to malignant hyperthermia. METHODS This study examined the effect of overexpressing a muscle-specific nonconducting dominant-negative TRPC6 channel in 20 RYR1-p.R163C and 20 wild-type mice and an equal number of nonexpressing controls, using calcium- and sodium-selective microelectrodes and Western blots. RESULTS RYR1-p.R163C mouse muscles have chronically elevated intracellular calcium and sodium levels compared to wild-type muscles. Transgenic expression of the nonconducting TRPC6 channel reduced intracellular calcium from 331 ± 34 nM (mean ± SD) to 190 ± 27 nM (P < 0.0001) and sodium from 15 ± 1 mM to 11 ± 1 mM (P < 0.0001). Its expression lowered the increase in intracellular Ca2+ of the TRPC6-specific activator hyperforin in RYR1-p.R163C muscle fibers from 52% (348 ± 37 nM to 537 ± 70 nM) to 14% (185 ± 11 nM to 210 ± 44 nM). Western blot analysis of TRPC3 and TRPC6 expression showed the expected increase in TRPC6 caused by overexpression of its dominant-negative transgene and a compensatory increase in expression of TRPC3. Although expression of the muscle-specific dominant-negative TRPC6 was able to modulate the increase in intracellular calcium during halothane exposure and prolonged life (35 ± 5 min vs. 15 ± 3 min; P < 0.0001), a slow, steady increase in calcium began after 20 min of halothane exposure, which eventually led to death. CONCLUSIONS These data support previous findings that TRPC channels play an important role in causing the intracellular calcium and sodium dyshomeostasis associated with RYR1 variants that are pathogenic for malignant hyperthermia. However, they also show that modulating TRPC channels alone is not sufficient to prevent the lethal effect of exposure to volatile anesthetic malignant hyperthermia-triggering agents. EDITOR’S PERSPECTIVE
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Aleman M, Zhang R, Feng W, Qi L, Lopez JR, Crowe C, Dong Y, Cherednichenko G, Pessah IN. Dietary Caffeine Synergizes Adverse Peripheral and Central Responses to Anesthesia in Malignant Hyperthermia Susceptible Mice. Mol Pharmacol 2020; 98:351-363. [PMID: 32764093 DOI: 10.1124/mol.120.119412] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2020] [Accepted: 07/31/2020] [Indexed: 11/22/2022] Open
Abstract
Ryanodine receptor (RYR) mutations confer stress-triggered malignant hyperthermia (MH) susceptibility. Dietary caffeine (CAF) is the most commonly consumed psychoactive compound by humans. CAF-triggered Ca2+ release and its influences on skeletal muscle contractility are widely used as experimental tools to study RYR function/dysfunction and diagnose MH susceptibility. We hypothesize that dietary CAF achieving blood levels measured in human plasma exacerbates the penetrance of RYR1 MH susceptibility mutations triggered by gaseous anesthetic, affecting both central and peripheral adverse responses. Heterozygous R163C-RYR1 (HET) MH susceptible mice are used to investigate the influences of dietary CAF on both peripheral and central responses before and after induction of halothane (HAL) maintenance anesthesia under experimental conditions that maintain normal core body temperature. HET mice receiving CAF (plasma CAF 893 ng/ml) have significantly shorter times to respiratory arrest compared with wild type, without altering blood chemistry or displaying hyperthermia or muscle rigor. Intraperitoneal bolus dantrolene before HAL prolongs time to respiratory arrest. A pilot electrographic study using subcutaneous electrodes reveals that dietary CAF does not alter baseline electroencephalogram (EEG) total power, but significantly shortens delay to isoelectric EEG, which precedes respiratory and cardiac arrest. CAF ± HAL are studied on RYR1 single-channel currents and HET myotubes to define molecular mechanisms of gene-by-environment synergism. Strong pharmacological synergism between CAF and HAL is demonstrated in both single-channel and myotube preparations. Central and peripheral nervous systems mediate adverse responses to HAL in a HET model of MH susceptibility exposed to dietary CAF, a modifiable lifestyle factor that may mitigate risks of acute and chronic diseases associated with RYR1 mutations. SIGNIFICANCE STATEMENT: Dietary caffeine at a human-relevant dose synergizes adverse peripheral and central responses to anesthesia in malignant hyperthermia susceptible mice. Synergism of these drugs can be attributed to their actions at ryanodine receptors.
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Affiliation(s)
- Monica Aleman
- Department of Molecular Biosciences, School of Veterinary Medicine (R.Z., W.F., J.R.L., Y.D., G.C., I.N.P.), Department of Medicine and Epidemiology, The William R. Pritchard Veterinary Medical Teaching Hospital, School of Veterinary Medicine (M.A., C.C.), and Department of Public Health Sciences, School of Medicine, School of Medicine (L.Q.), University of California, Davis, California
| | - Rui Zhang
- Department of Molecular Biosciences, School of Veterinary Medicine (R.Z., W.F., J.R.L., Y.D., G.C., I.N.P.), Department of Medicine and Epidemiology, The William R. Pritchard Veterinary Medical Teaching Hospital, School of Veterinary Medicine (M.A., C.C.), and Department of Public Health Sciences, School of Medicine, School of Medicine (L.Q.), University of California, Davis, California
| | - Wei Feng
- Department of Molecular Biosciences, School of Veterinary Medicine (R.Z., W.F., J.R.L., Y.D., G.C., I.N.P.), Department of Medicine and Epidemiology, The William R. Pritchard Veterinary Medical Teaching Hospital, School of Veterinary Medicine (M.A., C.C.), and Department of Public Health Sciences, School of Medicine, School of Medicine (L.Q.), University of California, Davis, California
| | - Lihong Qi
- Department of Molecular Biosciences, School of Veterinary Medicine (R.Z., W.F., J.R.L., Y.D., G.C., I.N.P.), Department of Medicine and Epidemiology, The William R. Pritchard Veterinary Medical Teaching Hospital, School of Veterinary Medicine (M.A., C.C.), and Department of Public Health Sciences, School of Medicine, School of Medicine (L.Q.), University of California, Davis, California
| | - Jose R Lopez
- Department of Molecular Biosciences, School of Veterinary Medicine (R.Z., W.F., J.R.L., Y.D., G.C., I.N.P.), Department of Medicine and Epidemiology, The William R. Pritchard Veterinary Medical Teaching Hospital, School of Veterinary Medicine (M.A., C.C.), and Department of Public Health Sciences, School of Medicine, School of Medicine (L.Q.), University of California, Davis, California
| | - Chelsea Crowe
- Department of Molecular Biosciences, School of Veterinary Medicine (R.Z., W.F., J.R.L., Y.D., G.C., I.N.P.), Department of Medicine and Epidemiology, The William R. Pritchard Veterinary Medical Teaching Hospital, School of Veterinary Medicine (M.A., C.C.), and Department of Public Health Sciences, School of Medicine, School of Medicine (L.Q.), University of California, Davis, California
| | - Yao Dong
- Department of Molecular Biosciences, School of Veterinary Medicine (R.Z., W.F., J.R.L., Y.D., G.C., I.N.P.), Department of Medicine and Epidemiology, The William R. Pritchard Veterinary Medical Teaching Hospital, School of Veterinary Medicine (M.A., C.C.), and Department of Public Health Sciences, School of Medicine, School of Medicine (L.Q.), University of California, Davis, California
| | - Genady Cherednichenko
- Department of Molecular Biosciences, School of Veterinary Medicine (R.Z., W.F., J.R.L., Y.D., G.C., I.N.P.), Department of Medicine and Epidemiology, The William R. Pritchard Veterinary Medical Teaching Hospital, School of Veterinary Medicine (M.A., C.C.), and Department of Public Health Sciences, School of Medicine, School of Medicine (L.Q.), University of California, Davis, California
| | - Isaac N Pessah
- Department of Molecular Biosciences, School of Veterinary Medicine (R.Z., W.F., J.R.L., Y.D., G.C., I.N.P.), Department of Medicine and Epidemiology, The William R. Pritchard Veterinary Medical Teaching Hospital, School of Veterinary Medicine (M.A., C.C.), and Department of Public Health Sciences, School of Medicine, School of Medicine (L.Q.), University of California, Davis, California
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15
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Lopez JR, Kaura V, Hopkins P, Liu X, Uryach A, Adams J, Allen PD. Transient Receptor Potential Cation Channels and Calcium Dyshomeostasis in a Mouse Model Relevant to Malignant Hyperthermia. Anesthesiology 2020; 133:364-376. [PMID: 32665491 PMCID: PMC7367496 DOI: 10.1097/aln.0000000000003387] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
BACKGROUND Until recently, the mechanism for the malignant hyperthermia crisis has been attributed solely to sustained massive Ca release from the sarcoplasmic reticulum on exposure to triggering agents. This study tested the hypothesis that transient receptor potential cation (TRPC) channels are important contributors to the Ca dyshomeostasis in a mouse model relevant to malignant hyperthermia. METHODS This study examined the mechanisms responsible for Ca dyshomeostasis in RYR1-p.G2435R mouse muscles and muscle cells using calcium and sodium ion selective microelectrodes, manganese quench of Fura2 fluorescence, and Western blots. RESULTS RYR1-p.G2435R mouse muscle cells have chronically elevated intracellular resting calcium and sodium and rate of manganese quench (homozygous greater than heterozygous) compared with wild-type muscles. After exposure to 1-oleoyl-2-acetyl-sn-glycerol, a TRPC3/6 activator, increases in intracellular resting calcium/sodium were significantly greater in RYR1-p.G2435R muscles (from 153 ± 11 nM/10 ± 0.5 mM to 304 ± 45 nM/14.2 ± 0.7 mM in heterozygotes P < 0.001] and from 251 ± 25 nM/13.9 ± 0.5 mM to 534 ± 64 nM/20.9 ± 1.5 mM in homozygotes [P < 0.001] compared with 123 ± 3 nM/8 ± 0.1 mM to 196 ± 27 nM/9.4 ± 0.7 mM in wild type). These increases were inhibited both by simply removing extracellular Ca and by exposure to either a nonspecific (gadolinium) or a newly available, more specific pharmacologic agent (SAR7334) to block TRPC6- and TRPC3-mediated cation influx into cells. Furthermore, local pretreatment with SAR7334 partially decreased the elevation of intracellular resting calcium that is seen in RYR1-p.G2435R muscles during exposure to halothane. Western blot analysis showed that expression of TRPC3 and TRPC6 were significantly increased in RYR1-p.G2435R muscles in a gene-dose-dependent manner, supporting their being a primary molecular basis for increased sarcolemmal cation influx. CONCLUSIONS Muscle cells in knock-in mice expressing the RYR1-p.G2435R mutation are hypersensitive to TRPC3/6 activators. This hypersensitivity can be negated with pharmacologic agents that block TRPC3/6 activity. This reinforces the working hypothesis that transient receptor potential cation channels play a critical role in causing intracellular calcium and sodium overload in malignant hyperthermia-susceptible muscle, both at rest and during the malignant hyperthermia crisis.
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Affiliation(s)
- Jose Rafael Lopez
- Department of Molecular Biosciences, School of Veterinary Medicine, University of California at Davis, Davis, CA 95616
- Department of Research, Mount Sinai, Medical Center, Miami, FL 33140, USA
| | - Vikas Kaura
- Malignant Hyperthermia Investigation Unit, St James’ University Hospital, Leeds, United Kingdom
| | - Phillip Hopkins
- Malignant Hyperthermia Investigation Unit, St James’ University Hospital, Leeds, United Kingdom
| | - Xiaochen Liu
- Malignant Hyperthermia Investigation Unit, St James’ University Hospital, Leeds, United Kingdom
| | - Arkady Uryach
- Division of Neonatology, Mount Sinai Medical Center, Miami, FL 33140, USA
| | - Jose Adams
- Division of Neonatology, Mount Sinai Medical Center, Miami, FL 33140, USA
| | - Paul D Allen
- Department of Molecular Biosciences, School of Veterinary Medicine, University of California at Davis, Davis, CA 95616
- Malignant Hyperthermia Investigation Unit, St James’ University Hospital, Leeds, United Kingdom
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16
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Flucher BE. Skeletal muscle Ca V1.1 channelopathies. Pflugers Arch 2020; 472:739-754. [PMID: 32222817 PMCID: PMC7351834 DOI: 10.1007/s00424-020-02368-3] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2020] [Revised: 03/06/2020] [Accepted: 03/17/2020] [Indexed: 12/15/2022]
Abstract
CaV1.1 is specifically expressed in skeletal muscle where it functions as voltage sensor of skeletal muscle excitation-contraction (EC) coupling independently of its functions as L-type calcium channel. Consequently, all known CaV1.1-related diseases are muscle diseases and the molecular and cellular disease mechanisms relate to the dual functions of CaV1.1 in this tissue. To date, four types of muscle diseases are known that can be linked to mutations in the CACNA1S gene or to splicing defects. These are hypo- and normokalemic periodic paralysis, malignant hyperthermia susceptibility, CaV1.1-related myopathies, and myotonic dystrophy type 1. In addition, the CaV1.1 function in EC coupling is perturbed in Native American myopathy, arising from mutations in the CaV1.1-associated protein STAC3. Here, we first address general considerations concerning the possible roles of CaV1.1 in disease and then discuss the state of the art regarding the pathophysiology of the CaV1.1-related skeletal muscle diseases with an emphasis on molecular disease mechanisms.
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Affiliation(s)
- Bernhard E Flucher
- Department of Physiology and Medical Biophysics, Medical University Innsbruck, Schöpfstraße 41, A6020, Innsbruck, Austria.
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17
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Schartner V, Laporte J, Böhm J. Abnormal Excitation-Contraction Coupling and Calcium Homeostasis in Myopathies and Cardiomyopathies. J Neuromuscul Dis 2020; 6:289-305. [PMID: 31356215 DOI: 10.3233/jnd-180314] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Muscle contraction requires specialized membrane structures with precise geometry and relies on the concerted interplay of electrical stimulation and Ca2+ release, known as excitation-contraction coupling (ECC). The membrane structure hosting ECC is called triad in skeletal muscle and dyad in cardiac muscle, and structural or functional defects of triads and dyads have been observed in a variety of myopathies and cardiomyopathies. Based on their function, the proteins localized at the triad/dyad can be classified into three molecular pathways: the Ca2+ release complex (CRC), store-operated Ca2+ entry (SOCE), and membrane remodeling. All three are mechanistically linked, and consequently, aberrations in any of these pathways cause similar disease entities. This review provides an overview of the clinical and genetic spectrum of triad and dyad defects with a main focus of attention on the underlying pathomechanisms.
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Affiliation(s)
- Vanessa Schartner
- Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), Illkirch, France.,INSERM U1258, Illkirch, France.,CNRS UMR7104, Illkirch, France.,Strasbourg University, Illkirch, France
| | - Jocelyn Laporte
- Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), Illkirch, France.,INSERM U1258, Illkirch, France.,CNRS UMR7104, Illkirch, France.,Strasbourg University, Illkirch, France
| | - Johann Böhm
- Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), Illkirch, France.,INSERM U1258, Illkirch, France.,CNRS UMR7104, Illkirch, France.,Strasbourg University, Illkirch, France
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18
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Gardner L, Miller DM, Daly C, Gupta PK, House C, Roiz de Sa D, Shaw MA, Hopkins PM. Investigating the genetic susceptibility to exertional heat illness. J Med Genet 2020; 57:531-541. [DOI: 10.1136/jmedgenet-2019-106461] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2019] [Revised: 11/25/2019] [Accepted: 12/21/2019] [Indexed: 12/16/2022]
Abstract
BackgroundWe aimed to identify rare (minor allele frequency ≤1%), potentially pathogenic non-synonymous variants in a well-characterised cohort with a clinical history of exertional heat illness (EHI) or exertional rhabdomyolysis (ER). The genetic link between malignant hyperthermia (MH) and EHI was investigated due to their phenotypic overlap.MethodsThe coding regions of 38 genes relating to skeletal muscle calcium homeostasis or exercise intolerance were sequenced in 64 patients (mostly military personnel) with a history of EHI, or ER and who were phenotyped using skeletal muscle in vitro contracture tests. We assessed the pathogenicity of variants using prevalence data, in silico analysis, phenotype and segregation evidence and by review of the literature.ResultsWe found 51 non-polymorphic, potentially pathogenic variants in 20 genes in 38 patients. Our data indicate that RYR1 p.T3711M (previously shown to be likely pathogenic for MH susceptibility) and RYR1 p.I3253T are likely pathogenic for EHI. PYGM p.A193S was found in 3 patients with EHI, which is significantly greater than the control prevalence (p=0.000025). We report the second case of EHI in which a missense variant at CACNA1S p.R498 has been found. Combinations of rare variants in the same or different genes are implicated in EHI.ConclusionWe confirm a role of RYR1 in the heritability of EHI as well as ER but highlight the likely genetic heterogeneity of these complex conditions. We propose defects, or combinations of defects, in skeletal muscle calcium homeostasis, oxidative metabolism and membrane excitability are associated with EHI.
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20
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RYR1 Sequence Variants in Myopathies: Expression and Functional Studies in Two Families. BIOMED RESEARCH INTERNATIONAL 2019; 2019:7638946. [PMID: 31165076 PMCID: PMC6500691 DOI: 10.1155/2019/7638946] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/14/2018] [Accepted: 03/19/2019] [Indexed: 12/26/2022]
Abstract
The skeletal muscle ryanodine receptor (RyR1), i.e., the Ca2+ channel of the sarco/endoplasmic reticulum (S/ER), and the voltage-dependent calcium channel Cav1.1 are the principal channels involved in excitation-contraction coupling in skeletal muscle. RYR1 gene variants are linked to distinct skeletal muscle disorders, including malignant hyperthermia susceptibility and central core disease (CCD), mainly with autosomal dominant inheritance, and autosomal recessive myopathies with a broad phenotypic and histopathological spectrum. The age at onset of RYR1-related myopathies varies from infancy to adulthood. We report the identification of four RYR1 variants in two Italian families: one with myopathy and variants c.4003C>T (p.R1335C) and c.7035C>A (p.S2345R), and another with CCD and variants c.9293G>T (p.S3098I) and c.14771_14772insTAGACAGGGTGTTGCTCTGTTGCCCTTCTT (p.F4924_V4925insRQGVALLPFF). We demonstrate that, in patient-specific lymphoblastoid cells, the c.4003C>T (p.R1335C) variant is not expressed and the in-frame 30-nucleotide insertion variant is expressed at a low level. Moreover, Ca2+ release in response to the RyR1 agonist 4-chloro-m-cresol and to thapsigargin showed that the c.7035C>A (p.S2345R) variant causes depletion of S/ER Ca2+ stores and that the compound heterozygosity for variant c.9293G>T (p.S3098I) and the 30-nucleotide insertion increases RyR1-dependent Ca2+ release without affecting ER Ca2+ stores. In conclusion, we detected and functionally characterized disease-causing variants of the RyR1 channel in patient-specific lymphoblastoid cells. This paper is dedicated to the memory and contribution of Luigi Del Vecchio.
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Chang L, Daly C, Miller DM, Allen PD, Boyle JP, Hopkins PM, Shaw MA. Permeabilised skeletal muscle reveals mitochondrial deficiency in malignant hyperthermia-susceptible individuals. Br J Anaesth 2019; 122:613-621. [PMID: 30916033 DOI: 10.1016/j.bja.2019.02.010] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2018] [Revised: 01/26/2019] [Accepted: 02/04/2019] [Indexed: 11/20/2022] Open
Abstract
BACKGROUND Individuals genetically susceptible to malignant hyperthermia (MH) exhibit hypermetabolic reactions when exposed to volatile anaesthetics. Mitochondrial dysfunction has previously been associated with the MH-susceptible (MHS) phenotype in animal models, but evidence of this in human MH is limited. METHODS We used high resolution respirometry to compare oxygen consumption rates (oxygen flux) between permeabilised human MHS and MH-negative (MHN) skeletal muscle fibres with or without prior exposure to halothane. A substrate-uncoupler-inhibitor titration protocol was used to measure the following components of the electron transport chain under conditions of oxidative phosphorylation (OXPHOS) or after uncoupling the electron transport system (ETS): complex I (CI), complex II (CII), CI+CII and, as a measure of mitochondrial mass, complex IV (CIV). RESULTS Baseline comparisons without halothane exposure showed significantly increased mitochondrial mass (CIV, P=0.021) but lower flux control ratios in CI+CII(OXPHOS) and CII(ETS) of MHS mitochondria compared with MHN (P=0.033 and 0.005, respectively) showing that human MHS mitochondria have a functional deficiency. Exposure to halothane triggered a hypermetabolic response in MHS mitochondria, significantly increasing mass-specific oxygen flux in CI(OXPHOS), CI+CII(OXPHOS), CI+CII(ETS), and CII(ETS) (P=0.001-0.012), while the rates in MHN samples were unaltered by halothane exposure. CONCLUSIONS We present evidence of mitochondrial dysfunction in human MHS skeletal muscle both at baseline and after halothane exposure.
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Affiliation(s)
- Leon Chang
- Leeds Institute of Medical Research at St. James's, University of Leeds, Leeds, UK
| | - Catherine Daly
- Malignant Hyperthermia Unit, St James's University Hospital, Leeds, UK
| | - Dorota M Miller
- Leeds Institute of Medical Research at St. James's, University of Leeds, Leeds, UK
| | - Paul D Allen
- Leeds Institute of Medical Research at St. James's, University of Leeds, Leeds, UK
| | - John P Boyle
- Leeds Institute of Cardiovascular and Metabolic Medicine, University of Leeds, Leeds, UK
| | - Philip M Hopkins
- Leeds Institute of Medical Research at St. James's, University of Leeds, Leeds, UK; Malignant Hyperthermia Unit, St James's University Hospital, Leeds, UK.
| | - Marie-Anne Shaw
- Leeds Institute of Medical Research at St. James's, University of Leeds, Leeds, UK
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22
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Merritt A, Booms P, Shaw MA, Miller DM, Daly C, Bilmen JG, Stowell KM, Allen PD, Steele DS, Hopkins PM. Assessing the pathogenicity of RYR1 variants in malignant hyperthermia. Br J Anaesth 2018; 118:533-543. [PMID: 28403410 DOI: 10.1093/bja/aex042] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/31/2017] [Indexed: 12/16/2022] Open
Abstract
Background . Missense variants in the ryanodine receptor 1 gene ( RYR1 ) are associated with malignant hyperthermia but only a minority of these have met the criteria for use in predictive DNA diagnosis. We examined the utility of a simplified method of segregation analysis and a functional assay for determining the pathogenicity of recurrent RYR1 variants associated with malignant hyperthermia. Methods . We identified previously uncharacterised RYR1 variants found in four or more malignant hyperthermia families and conducted simplified segregation analyses. An efficient cloning and mutagenesis strategy was used to express ryanodine receptor protein containing one of six RYR1 variants in HEK293 cells. Caffeine-induced calcium release, measured using a fluorescent calcium indicator, was compared in cells expressing each variant to that in cells expressing wild type ryanodine receptor protein. Results. We identified 43 malignant hyperthermia families carrying one of the six RYR1 variants. There was segregation of genotype with the malignant hyperthermia susceptibility phenotype in families carrying the p.E3104K and p.D3986E variants, but the number of informative meioses limited the statistical significance of the associations. HEK293 functional assays demonstrated an increased sensitivity of RyR1 channels containing the p.R2336H, p.R2355W, p.E3104K, p.G3990V and p.V4849I compared with wild type, but cells expressing p.D3986E had a similar caffeine sensitivity to cells expressing wild type RyR1. Conclusions . Segregation analysis is of limited value in assessing pathogenicity of RYR1 variants in malignant hyperthermia. Functional analyses in HEK293 cells provided evidence to support the use of p.R2336H, p.R2355W, p.E3104K, p.G3990V and p.V4849I for diagnostic purposes but not p.D3986E.
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Affiliation(s)
- A Merritt
- Leeds Institute of Biomedical & Clinical Sciences, University of Leeds, Leeds, UK
| | - P Booms
- Leeds Institute of Biomedical & Clinical Sciences, University of Leeds, Leeds, UK
| | - M-A Shaw
- Leeds Institute of Biomedical & Clinical Sciences, University of Leeds, Leeds, UK
| | - D M Miller
- Leeds Institute of Biomedical & Clinical Sciences, University of Leeds, Leeds, UK.,Malignant Hyperthermia Unit, St James's University Hospital, Leeds, UK
| | - C Daly
- Malignant Hyperthermia Unit, St James's University Hospital, Leeds, UK
| | - J G Bilmen
- Leeds Institute of Biomedical & Clinical Sciences, University of Leeds, Leeds, UK.,Malignant Hyperthermia Unit, St James's University Hospital, Leeds, UK
| | - K M Stowell
- Institute of Fundamental Sciences, Massey University, Palmerston North, New Zealand
| | - P D Allen
- Department of Molecular Biosciences, UC Davis, Davis, CA, USA
| | - D S Steele
- School of Biomedical Sciences, University of Leeds, Leeds, UK
| | - P M Hopkins
- Leeds Institute of Biomedical & Clinical Sciences, University of Leeds, Leeds, UK.,Malignant Hyperthermia Unit, St James's University Hospital, Leeds, UK
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Pancaroglu R, Van Petegem F. Calcium Channelopathies: Structural Insights into Disorders of the Muscle Excitation–Contraction Complex. Annu Rev Genet 2018; 52:373-396. [DOI: 10.1146/annurev-genet-120417-031311] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Ion channels are membrane proteins responsible for the passage of ions down their electrochemical gradients and across biological membranes. In this, they generate and shape action potentials and provide secondary messengers for various signaling pathways. They are often part of larger complexes containing auxiliary subunits and regulatory proteins. Channelopathies arise from mutations in the genes encoding ion channels or their associated proteins. Recent advances in cryo-electron microscopy have resulted in an explosion of ion channel structures in multiple states, generating a wealth of new information on channelopathies. Disease-associated mutations fall into different categories, interfering with ion permeation, protein folding, voltage sensing, ligand and protein binding, and allosteric modulation of channel gating. Prime examples of these are Ca2+-selective channels expressed in myocytes, for which multiple structures in distinct conformational states have recently been uncovered. We discuss the latest insights into these calcium channelopathies from a structural viewpoint.
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Affiliation(s)
- Raika Pancaroglu
- Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, British Columbia V6T 1Z3, Canada
| | - Filip Van Petegem
- Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, British Columbia V6T 1Z3, Canada
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Laugel-Haushalter V, Morkmued S, Stoetzel C, Geoffroy V, Muller J, Boland A, Deleuze JF, Chennen K, Pitiphat W, Dollfus H, Niederreither K, Bloch-Zupan A, Pungchanchaikul P. Genetic Evidence Supporting the Role of the Calcium Channel, CACNA1S, in Tooth Cusp and Root Patterning. Front Physiol 2018; 9:1329. [PMID: 30319441 PMCID: PMC6170876 DOI: 10.3389/fphys.2018.01329] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2018] [Accepted: 09/03/2018] [Indexed: 01/08/2023] Open
Abstract
In this study, we report a unique dominantly inherited disorganized supernumerary cusp and single root phenotype presented by 11 affected individuals belonging to 5 north-eastern Thai families. Using whole exome sequencing (WES) we identified a common single missense mutation that segregates with the phenotype in exon 6 of CACNA1S (Cav1.1) (NM_000069.2: c.[865A > G];[=] p.[Ile289Val];[=]), the Calcium Channel, Voltage-Dependent, L Type, Alpha-1s Subunit, OMIM ∗ 114208), affecting a highly conserved amino-acid isoleucine residue within the pore forming subdomain of CACNA1S protein. This is a strong genetic evidence that a voltage-dependent calcium ion channel is likely to play a role in influencing tooth morphogenesis and patterning.
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Affiliation(s)
- Virginie Laugel-Haushalter
- Laboratoire de Génétique Médicale, UMR_S INSERM U1112, IGMA, Faculté de Médecine, FMTS, Université de Strasbourg, Strasbourg, France
| | - Supawich Morkmued
- Biofilm Research Group, Department of Pediatric Dentistry, Faculty of Dentistry, Khon Kaen University, Khon Kaen, Thailand.,Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), CERBM, INSERM U 1258, CNRS- UMR 7104, Université de Strasbourg, Strasbourg, France
| | - Corinne Stoetzel
- Laboratoire de Génétique Médicale, UMR_S INSERM U1112, IGMA, Faculté de Médecine, FMTS, Université de Strasbourg, Strasbourg, France
| | - Véronique Geoffroy
- Laboratoire de Génétique Médicale, UMR_S INSERM U1112, IGMA, Faculté de Médecine, FMTS, Université de Strasbourg, Strasbourg, France
| | - Jean Muller
- Laboratoire de Génétique Médicale, UMR_S INSERM U1112, IGMA, Faculté de Médecine, FMTS, Université de Strasbourg, Strasbourg, France.,Laboratoires de Diagnostic Génétique, Hôpitaux Universitaires de Strasbourg, Strasbourg, France
| | - Anne Boland
- Centre National de Recherche en Génomique Humaine (CNRGH), Institut de Biologie François Jacob, Direction de la Recherche Fondamentale, Commissariat à l'Energie Atomique et aux Energies Alternatives, Paris, France
| | - Jean-François Deleuze
- Centre National de Recherche en Génomique Humaine (CNRGH), Institut de Biologie François Jacob, Direction de la Recherche Fondamentale, Commissariat à l'Energie Atomique et aux Energies Alternatives, Paris, France
| | - Kirsley Chennen
- Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), CERBM, INSERM U 1258, CNRS- UMR 7104, Université de Strasbourg, Strasbourg, France.,Department of Computer Science, ICube, CNRS - UMR 7357, Fédération de Médecine Translationnelle de Strasbourg, Université de Strasbourg, Strasbourg, France
| | - Waranuch Pitiphat
- Department of Community Dentistry, Faculty of Dentistry, Khon Kaen University, Khon Kaen, Thailand
| | - Hélène Dollfus
- Laboratoire de Génétique Médicale, UMR_S INSERM U1112, IGMA, Faculté de Médecine, FMTS, Université de Strasbourg, Strasbourg, France.,Centre de Référence pour les Affections Rares en Génétique Ophtalmologique, Filière SENSGENE, Hôpitaux Universitaires de Strasbourg, Strasbourg, France
| | - Karen Niederreither
- Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), CERBM, INSERM U 1258, CNRS- UMR 7104, Université de Strasbourg, Strasbourg, France.,Faculté de Chirurgie Dentaire, Université de Strasbourg, Strasbourg, France
| | - Agnès Bloch-Zupan
- Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), CERBM, INSERM U 1258, CNRS- UMR 7104, Université de Strasbourg, Strasbourg, France.,Faculté de Chirurgie Dentaire, Université de Strasbourg, Strasbourg, France.,Hôpitaux Universitaires de Strasbourg (HUS), Pôle de Médecine et Chirurgie Bucco-Dentaires Hôpital Civil, Centre de Référence des Maladies Rares Orales et Dentaires, O-Rares, Filière Santé Maladies Rares TETE COU, European Reference Network ERN CRANIO, Strasbourg, France
| | - Patimaporn Pungchanchaikul
- Biofilm Research Group, Department of Pediatric Dentistry, Faculty of Dentistry, Khon Kaen University, Khon Kaen, Thailand
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Genetic epidemiology of malignant hyperthermia in the UK. Br J Anaesth 2018; 121:944-952. [PMID: 30236257 DOI: 10.1016/j.bja.2018.06.028] [Citation(s) in RCA: 53] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2018] [Revised: 06/01/2018] [Accepted: 06/20/2018] [Indexed: 01/18/2023] Open
Abstract
BACKGROUND Gaps in our understanding of genetic susceptibility to malignant hyperthermia (MH) limit the application and interpretation of genetic diagnosis of the condition. Our aim was to define the prevalence and role of variants in the three genes implicated in MH susceptibility in the largest comprehensively phenotyped MH cohort worldwide. METHODS We initially included one individual from each positive family tested in the UK MH Unit since 1971 to detect variants in RYR1, CACNA1S, or STAC3. Screening for genetic variants has been ongoing since 1991 and has involved a range of techniques, most recently next generation sequencing. We assessed the pathogenicity of variants using standard guidelines, including family segregation studies. The prevalence of recurrent variants of unknown significance was compared with the prevalence reported in a large database of sequence variants in low-risk populations. RESULTS We have confirmed MH susceptibility in 795 independent families, for 722 of which we have a DNA sample. Potentially pathogenic variants were found in 555 families, with 25 RYR1 and one CACNA1S variants previously unclassified recurrent variants significantly over-represented (P<1×10-7) in our cohort compared with the Exome Aggregation Consortium database. There was genotype-phenotype discordance in 86 of 328 families suitable for segregation analysis. We estimate non-RYR1/CACNA1S/STAC3 susceptibility occurs in 14-23% of MH families. CONCLUSIONS Our data provide current estimates of the role of variants in RYR1, CACNA1S, and STAC3 in susceptibility to MH in a predominantly white European population.
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Malignant hyperthermia, environmental heat stress, and intracellular calcium dysregulation in a mouse model expressing the p.G2435R variant of RYR1. Br J Anaesth 2018; 121:953-961. [PMID: 30236258 DOI: 10.1016/j.bja.2018.07.008] [Citation(s) in RCA: 47] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2018] [Revised: 06/22/2018] [Accepted: 07/16/2018] [Indexed: 01/11/2023] Open
Abstract
BACKGROUND The human p.G2434R variant of the RYR1 gene is most frequently associated with malignant hyperthermia (MH) in the UK. We report the phenotype of a knock-in mouse that expresses the RYR1 variant p.G2435R, which is isogenetic with the human variant. METHODS We observed the general phenotype; determined the sensitivity of myotubes to caffeine-, KCl, and halothane-induced Ca2+ release; determined the in vivo response to halothane or increased ambient temperature; and determined the in vivo myoplasmic intracellular Ca2+ concentration in skeletal muscle before and during exposure to volatile anaesthetics. RESULTS RYR1 pG2435R/MH normal (MHS-Heterozygous[Het]) or RYR1 pG2435R/pG2435R (MHS-Homozygous[Hom]) mice were fully viable under typical rearing conditions, although some male MHS-Hom mice died spontaneously. The normalised half-maximal effective concentration (95% confidence interval) for intracellular Ca2+ release in myotubes in response to KCl [MH normal, MHN, 21.4 (19.8-23.1) mM; MHS-Het 16.2 (15.2-17.2) mM; MHS-Hom 11.2 (10.2-12.2) mM] and caffeine (MHN, 5.7 (5-6.3) mM; MHS-Het 4.5 (3.9-5.0) mM; MHS-Hom 1.77 (1.5-2.1) mM] exhibited a gene dose-dependent decrease, and there was a gene dose-dependent increase in halothane sensitivity. Intact animals show a gene dose-dependent susceptibility to MH with volatile anaesthetics or to heat stroke. RYR1 p.G2435R mice had elevated skeletal muscle intracellular resting [Ca2+]i, (values are expressed as mean (SD)) (MHN 123 (3) nM; MHS-Het 156 (16) nM; MHS-Hom 265 (32) nM; P<0.001) and [Na+]i (MHN 8 (0.1) mM; MHS-Het 10 (1) mM; MHS-Hom 14 (0.7) mM; P<0.001) that was further increased by exposure to volatile anaesthetics. CONCLUSIONS RYR1 pG2435R mice demonstrated gene dose-dependent in vitro and in vivo responses to pharmacological and environmental stressors that parallel those seen in patients with the human RYR1 variant p.G2434R.
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Hernández-Ochoa EO, Schneider MF. Voltage sensing mechanism in skeletal muscle excitation-contraction coupling: coming of age or midlife crisis? Skelet Muscle 2018; 8:22. [PMID: 30025545 PMCID: PMC6053751 DOI: 10.1186/s13395-018-0167-9] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2018] [Accepted: 06/26/2018] [Indexed: 11/10/2022] Open
Abstract
The process by which muscle fiber electrical depolarization is linked to activation of muscle contraction is known as excitation-contraction coupling (ECC). Our understanding of ECC has increased enormously since the early scientific descriptions of the phenomenon of electrical activation of muscle contraction by Galvani that date back to the end of the eighteenth century. Major advances in electrical and optical measurements, including muscle fiber voltage clamp to reveal membrane electrical properties, in conjunction with the development of electron microscopy to unveil structural details provided an elegant view of ECC in skeletal muscle during the last century. This surge of knowledge on structural and biophysical aspects of the skeletal muscle was followed by breakthroughs in biochemistry and molecular biology, which allowed for the isolation, purification, and DNA sequencing of the muscle fiber membrane calcium channel/transverse tubule (TT) membrane voltage sensor (Cav1.1) for ECC and of the muscle ryanodine receptor/sarcoplasmic reticulum Ca2+ release channel (RyR1), two essential players of ECC in skeletal muscle. In regard to the process of voltage sensing for controlling calcium release, numerous studies support the concept that the TT Cav1.1 channel is the voltage sensor for ECC, as well as also being a Ca2+ channel in the TT membrane. In this review, we present early and recent findings that support and define the role of Cav1.1 as a voltage sensor for ECC.
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Affiliation(s)
- Erick O. Hernández-Ochoa
- Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, 108 N. Greene Street, Baltimore, MD 21201 USA
| | - Martin F. Schneider
- Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, 108 N. Greene Street, Baltimore, MD 21201 USA
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28
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Flucher BE. Specific contributions of the four voltage-sensing domains in L-type calcium channels to gating and modulation. J Gen Physiol 2018; 148:91-5. [PMID: 27481711 PMCID: PMC4969803 DOI: 10.1085/jgp.201611663] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2016] [Accepted: 07/14/2016] [Indexed: 12/16/2022] Open
Affiliation(s)
- Bernhard E Flucher
- Division of Physiology, Department of Physiology and Medical Physics, Medical University Innsbruck, 6020 Innsbruck, Austria
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29
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Gartshore CJ, Salib MN, Renshaw AA, Molinski TF. Isolation of bastadin-6-O-sulfate and expedient purifications of bastadins-4, -5 and -6 from extracts of Ianthella basta. Fitoterapia 2018; 126:16-21. [PMID: 29221701 PMCID: PMC6391048 DOI: 10.1016/j.fitote.2017.12.003] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2017] [Revised: 11/29/2017] [Accepted: 12/04/2017] [Indexed: 11/17/2022]
Abstract
Bastadin-6-34-O-sulfate ester (8) was isolated from methanol extracts of Ianthella basta. The structure of 8 was characterized by analysis of MS and NMR data, and conversion through acid hydrolysis, to the parent compound, bastadin-6, which was identical by HPLC, MS and NMR with an authentic sample. An improved procedure for procurement of pure samples of bastadins-4 (4), -5 (5) and -6 (6) is described.
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Affiliation(s)
- Christopher J Gartshore
- Department of Chemistry and Biochemistry, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, 9500 Gilman Drive MC0358, La Jolla, San Diego, CA 92093, United States
| | - Mariam N Salib
- Department of Chemistry and Biochemistry, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, 9500 Gilman Drive MC0358, La Jolla, San Diego, CA 92093, United States
| | - August A Renshaw
- Department of Chemistry and Biochemistry, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, 9500 Gilman Drive MC0358, La Jolla, San Diego, CA 92093, United States
| | - Tadeusz F Molinski
- Department of Chemistry and Biochemistry, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, 9500 Gilman Drive MC0358, La Jolla, San Diego, CA 92093, United States; Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, 9500 Gilman Drive MC0358, La Jolla, San Diego, CA 92093, United States.
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30
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Hopkins PM, Gupta PK, Bilmen JG. Malignant hyperthermia. HANDBOOK OF CLINICAL NEUROLOGY 2018; 157:645-661. [DOI: 10.1016/b978-0-444-64074-1.00038-0] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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Abstract
This article reviews advancements in the genetics of malignant hyperthermia, new technologies and approaches for its diagnosis, and the existing limitations of genetic testing for malignant hyperthermia. It also reviews the various RYR1-related disorders and phenotypes, such as myopathies, exertional rhabdomyolysis, and bleeding disorders, and examines the connection between these disorders and malignant hyperthermia.
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32
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Polster A, Perni S, Filipova D, Moua O, Ohrtman JD, Bichraoui H, Beam KG, Papadopoulos S. Junctional trafficking and restoration of retrograde signaling by the cytoplasmic RyR1 domain. J Gen Physiol 2017; 150:293-306. [PMID: 29284662 PMCID: PMC5806685 DOI: 10.1085/jgp.201711879] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2017] [Accepted: 12/07/2017] [Indexed: 11/20/2022] Open
Abstract
The type 1 ryanodine receptor (RyR1) in skeletal muscle is a homotetrameric protein that releases Ca2+ from the sarcoplasmic reticulum (SR) in response to an "orthograde" signal from the dihydropyridine receptor (DHPR) in the plasma membrane (PM). Additionally, a "retrograde" signal from RyR1 increases the amplitude of the Ca2+ current produced by CaV1.1, the principle subunit of the DHPR. This bidirectional signaling is thought to depend on physical links, of unknown identity, between the DHPR and RyR1. Here, we investigate whether the isolated cytoplasmic domain of RyR1 can interact structurally or functionally with CaV1.1 by producing an N-terminal construct (RyR11:4300) that lacks the C-terminal membrane domain. In CaV1.1-null (dysgenic) myotubes, RyR11:4300 is diffusely distributed, but in RyR1-null (dyspedic) myotubes it localizes in puncta at SR-PM junctions containing endogenous CaV1.1. Fluorescence recovery after photobleaching indicates that diffuse RyR11:4300 is mobile, whereas resistance to being washed out with a large-bore micropipette indicates that the punctate RyR11:4300 stably associates with PM-SR junctions. Strikingly, expression of RyR11:4300 in dyspedic myotubes causes an increased amplitude, and slowed activation, of Ca2+ current through CaV1.1, which is almost identical to the effects of full-length RyR1. Fast protein liquid chromatography indicates that ∼25% of RyR11:4300 in diluted cytosolic lysate of transfected tsA201 cells is present in complexes larger in size than the monomer, and intermolecular fluorescence resonance energy transfer implies that RyR11:4300 is significantly oligomerized within intact tsA201 cells and dyspedic myotubes. A large fraction of these oligomers may be homotetramers because freeze-fracture electron micrographs reveal that the frequency of particles arranged like DHPR tetrads is substantially increased by transfecting RyR-null myotubes with RyR11:4300 In summary, the RyR1 cytoplasmic domain, separated from its SR membrane anchor, retains a tendency toward oligomerization/tetramerization, binds to SR-PM junctions in myotubes only if CaV1.1 is also present and is fully functional in retrograde signaling to CaV1.1.
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Affiliation(s)
- Alexander Polster
- Department of Physiology and Biophysics, University of Colorado Denver Anschutz Medical Campus, Denver, CO
| | - Stefano Perni
- Department of Physiology and Biophysics, University of Colorado Denver Anschutz Medical Campus, Denver, CO
| | - Dilyana Filipova
- Institute of Vegetative Physiology, University Hospital of Cologne, Cologne, Germany
| | - Ong Moua
- Department of Physiology and Biophysics, University of Colorado Denver Anschutz Medical Campus, Denver, CO
| | - Joshua D Ohrtman
- Department of Physiology and Biophysics, University of Colorado Denver Anschutz Medical Campus, Denver, CO
| | - Hicham Bichraoui
- Department of Physiology and Biophysics, University of Colorado Denver Anschutz Medical Campus, Denver, CO
| | - Kurt G Beam
- Department of Physiology and Biophysics, University of Colorado Denver Anschutz Medical Campus, Denver, CO
| | - Symeon Papadopoulos
- Institute of Vegetative Physiology, University Hospital of Cologne, Cologne, Germany
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Anandan C, Cipriani MA, Laughlin RS, Niu Z, Milone M. Rhabdomyolysis and fluctuating asymptomatic hyperCKemia associated with CACNA1S variant. Eur J Neurol 2017; 25:417-419. [PMID: 29193480 DOI: 10.1111/ene.13528] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2017] [Accepted: 11/24/2017] [Indexed: 12/25/2022]
Abstract
BACKGROUND AND PURPOSE CACNA1S encodes Cav 1.1, a voltage sensor for muscle excitation-contraction coupling, which activates the ryanodine receptor 1 (RYR1) leading to calcium release from the sarcoplasmic reticulum. CACNA1S mutations cause hypokalemic periodic paralysis, malignant hyperthermia and congenital myopathy. RYR1 mutations result in congenital myopathy, malignant hyperthermia and rhabdomyolysis. METHODS The aim was to describe a novel phenotype associated with a CACNA1S variant at a site previously linked to hypokalemic periodic paralysis. RESULTS The patient presented with fluctuating asymptomatic creatine kinase elevation after an episode of rhabdomyolysis but has no history of periodic paralysis. His muscle biopsy showed core-like structures occurring mainly in type 2 fibers. He carries a novel Cav 1.1 variant (p.Arg528Leu) affecting a highly conserved amino acid. Different mutations at the same location cause hypokalemic periodic paralysis. CONCLUSION This case underscores the similarity between the phenotypes caused by mutations in two functionally linked proteins, RYR1 and Cav 1.1.
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Affiliation(s)
- C Anandan
- Department of Neurology, Mayo Clinic, Rochester, MN, USA
| | - M A Cipriani
- Department of Family Medicine, Mayo Clinic, Rochester, MN, USA
| | - R S Laughlin
- Department of Neurology, Mayo Clinic, Rochester, MN, USA
| | - Z Niu
- Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, MN, USA.,Department of Clinical Genomics, Mayo Clinic, Rochester, MN, USA
| | - M Milone
- Department of Neurology, Mayo Clinic, Rochester, MN, USA
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Perez CF, Eltit JM, Lopez JR, Bodnár D, Dulhunty AF, Aditya S, Casarotto MG. Functional and structural characterization of a novel malignant hyperthermia-susceptible variant of DHPR-β 1a subunit (CACNB1). Am J Physiol Cell Physiol 2017; 314:C323-C333. [PMID: 29212769 DOI: 10.1152/ajpcell.00187.2017] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Malignant hyperthermia (MH) susceptibility has been recently linked to a novel variant of β1a subunit of the dihydropyridine receptor (DHPR), a channel essential for Ca2+ regulation in skeletal muscle. Here we evaluate the effect of the mutant variant V156A on the structure/function of DHPR β1a subunit and assess its role on Ca2+ metabolism of cultured myotubes. Using differential scanning fluorimetry, we show that mutation V156A causes a significant reduction in thermal stability of the Src homology 3/guanylate kinase core domain of β1a subunit. Expression of the variant subunit in β1-null mouse myotubes resulted in increased sensitivity to caffeine stimulation. Whole cell patch-clamp analysis of β1a-V156A-expressing myotubes revealed a -2 mV shift in voltage dependence of channel activation, but no changes in Ca2+ conductance, current kinetics, or sarcoplasmic reticulum Ca2+ load were observed. Measurement of resting free Ca2+ and Na+ concentrations shows that both cations were significantly elevated in β1a-V156A-expressing myotubes and that these changes were linked to increased rates of plasmalemmal Ca2+ entry through Na+/Ca2+ exchanger and/or transient receptor potential canonical channels. Overall, our data show that mutant variant V156A results in instability of protein subdomains of β1a subunit leading to a phenotype of Ca2+ dysregulation that partly resembles that of other MH-linked mutations of DHPR α1S subunit. These data prove that homozygous expression of variant β1a-V156A has the potential to be a pathological variant, although it may require other gene defects to cause a full MH phenotype.
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Affiliation(s)
- Claudio F Perez
- Department of Anesthesiology, Brigham and Women's Hospital, Harvard Medical School , Boston, Massachusetts
| | - Jose M Eltit
- Department of Physiology and Biophysics, School of Medicine, Virginia Commonwealth University , Richmond, Virginia
| | - Jose R Lopez
- Department of Molecular Biosciences, University of California , Davis, California
| | - Dóra Bodnár
- Department of Anesthesiology, Brigham and Women's Hospital, Harvard Medical School , Boston, Massachusetts
| | - Angela F Dulhunty
- John Curtin School of Medical Research, Australian National University , Canberra , Australia
| | - Shouvik Aditya
- John Curtin School of Medical Research, Australian National University , Canberra , Australia
| | - Marco G Casarotto
- John Curtin School of Medical Research, Australian National University , Canberra , Australia
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Flucher BE, Tuluc P. How and why are calcium currents curtailed in the skeletal muscle voltage-gated calcium channels? J Physiol 2017; 595:1451-1463. [PMID: 27896815 PMCID: PMC5330888 DOI: 10.1113/jp273423] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2016] [Accepted: 11/24/2016] [Indexed: 01/09/2023] Open
Abstract
Voltage‐gated calcium channels represent the sole mechanism converting electrical signals of excitable cells into cellular functions such as contraction, secretion and gene regulation. Specific voltage‐sensing domains detect changes in membrane potential and control channel gating. Calcium ions entering through the channel function as second messengers regulating cell functions, with the exception of skeletal muscle, where CaV1.1 essentially does not function as a channel but activates calcium release from intracellular stores. It has long been known that calcium currents are dispensable for skeletal muscle contraction. However, the questions as to how and why the channel function of CaV1.1 is curtailed remained obscure until the recent discovery of a developmental CaV1.1 splice variant with normal channel functions. This discovery provided new means to study the molecular mechanisms regulating the channel gating and led to the understanding that in skeletal muscle, calcium currents need to be restricted to allow proper regulation of fibre type specification and to prevent mitochondrial damage.
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Affiliation(s)
- Bernhard E Flucher
- Department of Physiology and Medical Physics, Medical University Innsbruck, Austria
| | - Petronel Tuluc
- Pharmacology and Toxicology, Institute of Pharmacy, University of Innsbruck, Austria
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Thompson SJ, Riazi S, Kraeva N, Noseworthy MD, Rayner TE, Schneiderman JE, Cifra B, Wells GD. Skeletal Muscle Metabolic Dysfunction in Patients With Malignant Hyperthermia Susceptibility. Anesth Analg 2017; 125:434-441. [PMID: 28682948 PMCID: PMC9940015 DOI: 10.1213/ane.0000000000002232] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
BACKGROUND Malignant hyperthermia (MH), a pharmacogenetic disorder of skeletal muscle, presents with a potentially lethal hypermetabolic reaction to certain anesthetics. However, some MH-susceptible patients experience muscle weakness, fatigue, and exercise intolerance in the absence of anesthetic triggers. The objective of this exploratory study was to elucidate the pathophysiology of exercise intolerance in patients tested positive for MH with the caffeine-halothane contracture test. To this end, we used phosphorus magnetic resonance spectroscopy, blood oxygen level-dependent functional magnetic resonance imaging (MRI), and traditional exercise testing to compare skeletal muscle metabolism in MH-positive patients and healthy controls. METHODS Skeletal muscle metabolism was assessed using phosphorus magnetic resonance spectroscopy and blood oxygen level-dependent functional MRI in 29 MH-positive patients and 20 healthy controls. Traditional measures of physical capacity were employed to measure aerobic capacity, anaerobic capacity, and muscle strength. RESULTS During 30- and 60-second exercise, MH-positive patients had significantly lower ATP production via the oxidative pathway compared to healthy controls. MH-positive patients also had a longer recovery time with blood oxygen level-dependent functional MRI compared to healthy controls. Exercise testing revealed lower aerobic and anaerobic capacity in MH-positive patients compared to healthy controls. CONCLUSIONS Results of this exploratory study suggest that MH-positive patients have impaired aerobic metabolism compared to healthy individuals. This could explain the exercise intolerance exhibited in MH-susceptible patient population.
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Affiliation(s)
- Sara J. Thompson
- Faculty of Kinesiology and Physical Education, University of Toronto, Toronto, Ontario, Canada
| | - Sheila Riazi
- Malignant Hyperthermia Investigation Unit, Toronto General Hospital, Toronto, Ontario, Canada,Department of Anesthesia, University of Toronto, Toronto, Ontario, Canada
| | - Natalia Kraeva
- Malignant Hyperthermia Investigation Unit, Toronto General Hospital, Toronto, Ontario, Canada
| | - Michael D. Noseworthy
- Department of Electrical and Computer Engineering, School of Biomedical Engineering, McMaster University, Hamilton, Ontario, Canada
| | - Tammy E. Rayner
- Department of Diagnostic Imaging, the Hospital for Sick Children, Toronto, Ontario, Canada
| | - Jane E. Schneiderman
- Faculty of Kinesiology and Physical Education, University of Toronto, Toronto, Ontario, Canada,Physiology and Experimental Medicine, the Hospital for Sick Children, Toronto, Ontario, Canada
| | - Barbara Cifra
- Division of Cardiology, the Labatt Family Heart Centre, the Hospital for Sick Children, Toronto, Ontario, Canada
| | - Greg D. Wells
- Faculty of Kinesiology and Physical Education, University of Toronto, Toronto, Ontario, Canada,Physiology and Experimental Medicine, the Hospital for Sick Children, Toronto, Ontario, Canada
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Beam TA, Loudermilk EF, Kisor DF. Pharmacogenetics and pathophysiology of CACNA1S mutations in malignant hyperthermia. Physiol Genomics 2016; 49:81-87. [PMID: 28011884 DOI: 10.1152/physiolgenomics.00126.2016] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Revised: 12/14/2016] [Indexed: 12/27/2022] Open
Abstract
A review of the pharmacogenetics (PGt) and pathophysiology of calcium voltage-gated channel subunit alpha1 S (CACNA1S) mutations in malignant hyperthermia susceptibility type 5 (MHS5; MIM #60188) is presented. Malignant hyperthermia (MH) is a life-threatening hypermetabolic state of skeletal muscle usually induced by volatile, halogenated anesthetics and/or the depolarizing neuromuscular blocker succinylcholine. In addition to ryanodine receptor 1 (RYR1) mutations, several CACNA1S mutations are known to be risk factors for increased susceptibility to MH (MHS). However, the presence of these pathogenic CACNA1S gene variations cannot be used to positively predict MH since the condition is genetically heterogeneous with variable expression and incomplete penetrance. At present, one or at most six CACNA1S mutations display significant linkage or association either to clinically diagnosed MH or to MHS as determined by contracture testing. Additional pathogenic variants in CACNA1S, either alone or in combination with genes affecting Ca2+ homeostasis, are likely to be discovered in association to MH as whole exome sequencing becomes more commonplace.
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Affiliation(s)
- Teresa A Beam
- Department of Pharmaceutical Sciences, Manchester University College of Pharmacy, Natural and Health Sciences, Fort Wayne, Indiana; and
| | - Emily F Loudermilk
- Department of Pharmaceutical and Biomedical Sciences, Ohio Northern University, College of Pharmacy, Ada, Ohio
| | - David F Kisor
- Department of Pharmaceutical Sciences, Manchester University College of Pharmacy, Natural and Health Sciences, Fort Wayne, Indiana; and
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Congenital myopathy results from misregulation of a muscle Ca2+ channel by mutant Stac3. Proc Natl Acad Sci U S A 2016; 114:E228-E236. [PMID: 28003463 DOI: 10.1073/pnas.1619238114] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Skeletal muscle contractions are initiated by an increase in Ca2+ released during excitation-contraction (EC) coupling, and defects in EC coupling are associated with human myopathies. EC coupling requires communication between voltage-sensing dihydropyridine receptors (DHPRs) in transverse tubule membrane and Ca2+ release channel ryanodine receptor 1 (RyR1) in the sarcoplasmic reticulum (SR). Stac3 protein (SH3 and cysteine-rich domain 3) is an essential component of the EC coupling apparatus and a mutation in human STAC3 causes the debilitating Native American myopathy (NAM), but the nature of how Stac3 acts on the DHPR and/or RyR1 is unknown. Using electron microscopy, electrophysiology, and dynamic imaging of zebrafish muscle fibers, we find significantly reduced DHPR levels, functionality, and stability in stac3 mutants. Furthermore, stac3NAM myofibers exhibited increased caffeine-induced Ca2+ release across a wide range of concentrations in the absence of altered caffeine sensitivity as well as increased Ca2+ in internal stores, which is consistent with increased SR luminal Ca2+ These findings define critical roles for Stac3 in EC coupling and human disease.
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Bannister RA. Bridging the myoplasmic gap II: more recent advances in skeletal muscle excitation-contraction coupling. ACTA ACUST UNITED AC 2016; 219:175-82. [PMID: 26792328 DOI: 10.1242/jeb.124123] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
In skeletal muscle, excitation-contraction (EC) coupling relies on the transmission of an intermolecular signal from the voltage-sensing regions of the L-type Ca(2+) channel (Ca(V)1.1) in the plasma membrane to the channel pore of the type 1 ryanodine receptor (RyR1) nearly 10 nm away in the membrane of the sarcoplasmic reticulum (SR). Even though the roles of Ca(V)1.1 and RyR1 as voltage sensor and SR Ca(2+) release channel, respectively, have been established for nearly 25 years, the mechanism underlying communication between these two channels remains undefined. In the course of this article, I will review current viewpoints on this topic with particular emphasis on recent studies.
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Affiliation(s)
- Roger A Bannister
- Department of Medicine-Cardiology Division, University of Colorado Denver-Anschutz Medical Campus, 12700 East 19th Avenue, Room 8006, B-139, Aurora, CO 80045, USA
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Lavorato M, Gupta PK, Hopkins PM, Franzini-Armstrong C. Skeletal Muscle Microalterations in Patients Carrying Malignant Hyperthermia-Related Mutations of the e-c Coupling Machinery. Eur J Transl Myol 2016; 26:6105. [PMID: 28078069 PMCID: PMC5220216 DOI: 10.4081/ejtm.2016.6105] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
We have compared the ultrastructure of skeletal muscle biopsies from patients that have survived a [Malignant Hyperthermia, MH] episode and siblings that test positive for MH susceptibility with those from siblings that tested negatives. The aim is to establish whether life long exposure to the MH-related mutation effects may result in subtle abnormalities even in the absence of active episodes and/or clinically detectable deficiencies. Although a specific ultrastructural signature for MH mutants cannot be demonstrated, an MH related pattern of minor alterations does exist. These include the tendency for micro damage to the contractile apparatus and a higher than normal level of mitochondrial abnormalities.
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Affiliation(s)
- Manuela Lavorato
- Department of Cell and Developmental Biology, University of Pennsylvania School of Medicine , Philadelphia PA, USA
| | - Pawan K Gupta
- Malignant Hyperthermia Unit, Leeds Institute of Biomedical and Clinical Sciences, St James's University Hospital , Leeds, UK
| | - Philip M Hopkins
- Malignant Hyperthermia Unit, Leeds Institute of Biomedical and Clinical Sciences, St James's University Hospital , Leeds, UK
| | - Clara Franzini-Armstrong
- Department of Cell and Developmental Biology, University of Pennsylvania School of Medicine , Philadelphia PA, USA
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Treves S, Jungbluth H, Voermans N, Muntoni F, Zorzato F. Ca 2+ handling abnormalities in early-onset muscle diseases: Novel concepts and perspectives. Semin Cell Dev Biol 2016; 64:201-212. [PMID: 27427513 DOI: 10.1016/j.semcdb.2016.07.017] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2016] [Accepted: 07/14/2016] [Indexed: 12/17/2022]
Abstract
The physiological process by which Ca2+ is released from the sarcoplasmic reticulum is called excitation-contraction coupling; it is initiated by an action potential which travels deep into the muscle fiber where it is sensed by the dihydropyridine receptor, a voltage sensing L-type Ca2+channel localized on the transverse tubules. Voltage-induced conformational changes in the dihydropyridine receptor activate the ryanodine receptor Ca2+ release channel of the sarcoplasmic reticulum. The released Ca2+ binds to troponin C, enabling contractile thick-thin filament interactions. The Ca2+ is subsequently transported back into the sarcoplasmic reticulum by specialized Ca2+ pumps (SERCA), preparing the muscle for a new cycle of contraction. Although other proteins are involved in excitation-contraction coupling, the mechanism described above emphasizes the unique role played by the two Ca2+ channels (the dihydropyridine receptor and the ryanodine receptor), the SERCA Ca2+ pumps and the exquisite spatial organization of the membrane compartments endowed with the proteins responsible for this mechanism to function rapidly and efficiently. Research over the past two decades has uncovered the fine details of excitation-contraction coupling under normal conditions while advances in genomics have helped to identify mutations in novel genes in patients with neuromuscular disorders. While it is now clear that many patients with congenital muscle diseases carry mutations in genes encoding proteins directly involved in Ca2+ homeostasis, it has become apparent that mutations are also present in genes encoding for proteins not thought to be directly involved in Ca2+ regulation. Ongoing research in the field now focuses on understanding the functional effect of individual mutations, as well as understanding the role of proteins not specifically located in the sarcoplasmic reticulum which nevertheless are involved in Ca2+ regulation or excitation-contraction coupling. The principal challenge for the future is the identification of drug targets that can be pharmacologically manipulated by small molecules, with the ultimate aim to improve muscle function and quality of life of patients with congenital muscle disorders. The aim of this review is to give an overview of the most recent findings concerning Ca2+ dysregulation and its impact on muscle function in patients with congenital muscle disorders due to mutations in proteins involved in excitation-contraction coupling and more broadly on Ca2+ homeostasis.
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Affiliation(s)
- Susan Treves
- Departments of Biomedicine and Anesthesia, Basel University Hospital, 4031 Basel, Switzerland; Department of Life Sciences, General Pathology Section, University of Ferrara, 44100 Ferrara, Italy.
| | - Heinz Jungbluth
- Department of Paediatric Neurology, Neuromuscular Service, Evelina Children's Hospital, St. Thomas' Hospital, London, United Kingdom; Randall Division for Cell and Molecular Biophysics, Muscle Signalling Section, King's College, London, United Kingdom; Department of Basic and Clinical Neuroscience, IoPPN, King's College, London, United Kingdom
| | - Nicol Voermans
- Department of Neurology, Radboud University Medical Centre, Nijmegen, The Netherlands
| | - Francesco Muntoni
- Dubowitz Neuromuscular Centre, Institute of Child Health, University College London, United Kingdom
| | - Francesco Zorzato
- Departments of Biomedicine and Anesthesia, Basel University Hospital, 4031 Basel, Switzerland; Department of Life Sciences, General Pathology Section, University of Ferrara, 44100 Ferrara, Italy
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Stephens J, Schiemann AH, Roesl C, Miller D, Massey S, Pollock N, Bulger T, Stowell K. Functional analysis of RYR1 variants linked to malignant hyperthermia. Temperature (Austin) 2016; 3:328-339. [PMID: 27857962 PMCID: PMC4964997 DOI: 10.1080/23328940.2016.1153360] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2016] [Revised: 02/04/2016] [Accepted: 02/05/2016] [Indexed: 11/04/2022] Open
Abstract
Malignant hyperthermia manifests as a rapid and sustained rise in temperature in response to pharmacological triggering agents, e.g. inhalational anesthetics and the muscle relaxant suxamethonium. Other clinical signs include an increase in end-tidal CO2, increased O2 consumption, as well as tachycardia, and if untreated a malignant hyperthermia episode can result in death. The metabolic changes are caused by dysregulation of skeletal muscle Ca2+ homeostasis, resulting from a defective ryanodine receptor Ca2+ channel, which resides in the sarcoplasmic reticulum and controls the flux of Ca2+ ions from intracellular stores to the cytoplasm. Most genetic variants associated with susceptibility to malignant hyperthermia occur in the RYR1 gene encoding the ryanodine receptor type 1. While malignant hyperthermia susceptibility can be diagnosed by in vitro contracture testing of skeletal muscle biopsy tissue, it is advantageous to use DNA testing. Currently only 35 of over 400 potential variants in RYR1 have been classed as functionally causative of malignant hyperthermia and thus can be used for DNA diagnostic tests. Here we describe functional analysis of 2 RYR1 variants (c. 7042_7044delCAG, p.ΔGlu2348 and c.641C>T, p.Thr214Met) that occur in the same malignant hyperthermia susceptible family. The p.Glu2348 deletion, causes hypersensitivity to ryanodine receptor agonists using in vitro analysis of cloned human RYR1 cDNA expressed in HEK293T cells, while the Thr214Met substitution, does not appear to significantly alter sensitivity to agonist in the same system. We suggest that the c. 7042_7044delCAG, p.ΔGlu2348 RYR1 variant could be added to the list of diagnostic mutations for susceptibility to malignant hyperthermia.
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Affiliation(s)
- Jeremy Stephens
- Institute of Fundamental Sciences, Massey University , Palmerston North, New Zealand
| | - Anja H Schiemann
- Institute of Fundamental Sciences, Massey University , Palmerston North, New Zealand
| | - Cornelia Roesl
- Centre for Integrative Physiology, The University of Edinburgh , Edinburgh, United Kingdom
| | - Dorota Miller
- UK Malignant Hyperthermia Investigation Unit, Leeds Institute of Biomedical & Clinical Sciences, School of Medicine, University of Leeds, St. James's University Hospital , Leeds, United Kingdom
| | - Sean Massey
- Institute of Fundamental Sciences, Massey University , Palmerston North, New Zealand
| | - Neil Pollock
- Anaesthetic Department, Palmerston North Hospital , Palmerston North, New Zealand
| | - Terasa Bulger
- Anaesthetic Department, Palmerston North Hospital , Palmerston North, New Zealand
| | - Kathryn Stowell
- Institute of Fundamental Sciences, Massey University , Palmerston North, New Zealand
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Abstract
Familial disorders of skeletal muscle excitability were initially described early in the last century and are now known to be caused by mutations of voltage-gated ion channels. The clinical manifestations are often striking, with an inability to relax after voluntary contraction (myotonia) or transient attacks of severe weakness (periodic paralysis). An essential feature of these disorders is fluctuation of symptoms that are strongly impacted by environmental triggers such as exercise, temperature, or serum K(+) levels. These phenomena have intrigued physiologists for decades, and in the past 25 years the molecular lesions underlying these disorders have been identified and mechanistic studies are providing insights for therapeutic strategies of disease modification. These familial disorders of muscle fiber excitability are "channelopathies" caused by mutations of a chloride channel (ClC-1), sodium channel (NaV1.4), calcium channel (CaV1.1), and several potassium channels (Kir2.1, Kir2.6, and Kir3.4). This review provides a synthesis of the mechanistic connections between functional defects of mutant ion channels, their impact on muscle excitability, how these changes cause clinical phenotypes, and approaches toward therapeutics.
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Affiliation(s)
- Stephen C Cannon
- Department of Physiology, David Geffen School of Medicine, UCLA, Los Angeles, CA, USA
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44
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Alvarellos ML, McDonagh EM, Patel S, McLeod HL, Altman RB, Klein TE. PharmGKB summary: succinylcholine pathway, pharmacokinetics/pharmacodynamics. Pharmacogenet Genomics 2015; 25:622-30. [PMID: 26398623 PMCID: PMC4631707 DOI: 10.1097/fpc.0000000000000170] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Affiliation(s)
| | | | - Sephalie Patel
- Department of Anesthesiology, Moffitt Cancer Center, Tampa, Florida, USA
| | - Howard L. McLeod
- DeBartolo Family Personalized Medicine Institute, Moffitt Cancer Center, Tampa, Florida, USA
| | - Russ B. Altman
- Department of Genetics, Stanford University, Stanford, California, USA
- Department of Bioengineering, Stanford University, Stanford, California, USA
| | - Teri E. Klein
- Department of Genetics, Stanford University, Stanford, California, USA
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[Telephone enquiries on the topic of malignant hyperthermia: Evaluation of the content and subsequent diagnostic results at the MH Center Leipzig]. Anaesthesist 2015; 65:36-41. [PMID: 26481388 DOI: 10.1007/s00101-015-0099-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2015] [Revised: 08/25/2015] [Accepted: 09/01/2015] [Indexed: 10/22/2022]
Abstract
BACKGROUND Malignant hyperthermia (MH) is an autosomal dominant metabolic myopathy. The in vitro contracture test (IVCT) is still considered to be the gold standard for diagnosing a disposition for MH. However, advances in genetic testing for MH disposition have supplemented or even replaced the invasive procedure of the IVCT. Information about MH can be obtained by either contacting the hotline for MH as a nationwide 24 h/7 days a week service or one of the regional MH centers. METHODS The protocols of telephone conversations concerning MH at the MH Center University Leipzig were retrospectively analyzed. Data were collected from January 2011 to March 2015. Additionally, the results of the IVCT and genetic testing evolving from the counseling interviews were examined. RESULTS A total of 205 telephone calls were documented during the period in question and an IVCT was performed as a consequence of 112 of the telephone calls. The IVCT resulted in 27 individuals being identified as MH susceptible which was subsequently diagnosed in 15 individuals with known familial MH disposition and 12 individuals were identified as new index patients. In 24 individuals a total of 13 different mutations were detected and of these 4 mutations were causative concerning MH. Of the 205 telephone calls 131 were private and 74 of medical professional origin. Among the private enquiries MH disposition within the family was a frequent reason for contacting the MH Center (61.8%). Conversations relating to MH-like symptoms during general anesthesia were carried out with 35.1% of medical doctors and with 22.9% of private callers. Advice about neuromuscular symptoms of unknown genesis was given to 15.3% of private individuals and to 24.3% of medical doctors. Overall MH topics were discussed with 23% (N = 17) of the medical profession and approximately half of these were anesthesiologists (N = 8). Not a single call was documented for the treatment of a suspected MH crisis. CONCLUSION Private individuals and families affected by a MH disposition often showed good compliance with respect to counseling and diagnostics for MH and contacted the MH center more often than medical doctors. A more comprehensive cooperation with the medical profession is preferable and necessary to obtain a systematic and broad synopsis of characteristic and uncharacteristic signs and symptoms of MH. The telephone conversations analyzed as well as the diagnostic results (IVCT and genetic testing) underline that MH disposition is still a current and relevant topic.
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46
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Manno C, Ríos E. A better method to measure total calcium in biological samples yields immediate payoffs. ACTA ACUST UNITED AC 2015; 145:167-71. [PMID: 25712015 PMCID: PMC4338160 DOI: 10.1085/jgp.201511370] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Affiliation(s)
- Carlo Manno
- Department of Molecular Biophysics and Physiology, Section of Cellular Signaling, Rush University, Chicago, IL 60612
| | - Eduardo Ríos
- Department of Molecular Biophysics and Physiology, Section of Cellular Signaling, Rush University, Chicago, IL 60612
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Hopkins P, Rüffert H, Snoeck M, Girard T, Glahn K, Ellis F, Müller C, Urwyler A. European Malignant Hyperthermia Group guidelines for investigation of malignant hyperthermia susceptibility. Br J Anaesth 2015; 115:531-9. [DOI: 10.1093/bja/aev225] [Citation(s) in RCA: 133] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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48
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Fiszer D, Shaw MA, Fisher NA, Carr IM, Gupta PK, Watkins EJ, de Sa DR, Kim JH, Hopkins PM. Next-generation Sequencing of RYR1 and CACNA1S in Malignant Hyperthermia and Exertional Heat Illness. Anesthesiology 2015; 122:1033-46. [PMID: 25658027 PMCID: PMC4472733 DOI: 10.1097/aln.0000000000000610] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
BACKGROUND Variants in RYR1 are associated with the majority of cases of malignant hyperthermia (MH), a form of heat illness pharmacogenetically triggered by general anesthetics, and they have also been associated with exertional heat illness (EHI). CACNA1S has also been implicated in MH. The authors applied a targeted next-generation sequencing approach to identify variants in RYR1 and CACNA1S in a cohort of unrelated patients diagnosed with MH susceptibility. They also provide the first comprehensive report of sequencing of these two genes in a cohort of survivors of EHI. METHODS DNA extracted from blood was genotyped using a "long" polymerase chain reaction technique, with sequencing on the Illumina GAII or MiSeq platforms (Illumina Inc., USA). Variants were assessed for pathogenicity using bioinformatic approaches. For further follow-up, DNA from additional family members and up to 211 MH normal and 556 MH-susceptible unrelated individuals was tested. RESULTS In 29 MH patients, the authors identified three pathogenic and four novel RYR1 variants, with a further five RYR1 variants previously reported in association with MH. Three novel RYR1 variants were found in the EHI cohort (n = 28) along with two more previously reported in association with MH. Two other variants were reported previously associated with centronuclear myopathy. The authors found one and three rare variants of unknown significance in CACNA1S in the MH and EHI cohorts, respectively. CONCLUSIONS Targeted next-generation sequencing proved efficient at identifying diagnostically useful and potentially implicated variants in RYR1 and CACNA1S in MH and EHI.
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Affiliation(s)
- Dorota Fiszer
- Leeds Institute of Biomedical & Clinical Sciences, School of Medicine, University of Leeds, United Kingdom
- Malignant Hyperthermia Investigation Unit, St. James’s University Hospital, Leeds, United Kingdom
| | - Marie-Anne Shaw
- Leeds Institute of Biomedical & Clinical Sciences, School of Medicine, University of Leeds, United Kingdom
- Malignant Hyperthermia Investigation Unit, St. James’s University Hospital, Leeds, United Kingdom
| | - Nickla A. Fisher
- Malignant Hyperthermia Investigation Unit, St. James’s University Hospital, Leeds, United Kingdom
| | - Ian M. Carr
- Leeds Institute of Biomedical & Clinical Sciences, School of Medicine, University of Leeds, United Kingdom
| | - Pawan K. Gupta
- Malignant Hyperthermia Investigation Unit, St. James’s University Hospital, Leeds, United Kingdom
| | - Elizabeth J. Watkins
- Malignant Hyperthermia Investigation Unit, St. James’s University Hospital, Leeds, United Kingdom
| | - Daniel Roiz de Sa
- Environmental Medicine and Science Division, Institute of Naval Medicine, Alverstoke, Hampshire, United Kingdom
| | - Jerry H. Kim
- Department of Anesthesiology and Pain Medicine, University of Washington, Seattle, Washington
| | - Philip M. Hopkins
- Leeds Institute of Biomedical & Clinical Sciences, School of Medicine, University of Leeds, United Kingdom
- Malignant Hyperthermia Investigation Unit, St. James’s University Hospital, Leeds, United Kingdom
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Gillies RL, Bjorksten AR, Du Sart D, Hockey BM. Analysis of the entire ryanodine receptor type 1 and alpha 1 subunit of the dihydropyridine receptor (CACNA1S) coding regions for variants associated with malignant hyperthermia in Australian families. Anaesth Intensive Care 2015; 43:157-66. [PMID: 25735680 DOI: 10.1177/0310057x1504300204] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Defects in the genes coding for the skeletal muscle ryanodine receptor (RYR1) and alpha 1 subunit of the dihydropyridine receptor (CACNA1S) have been identified as causative for malignant hyperthermia (MH). Sixty-two MH susceptible individuals presenting to the same diagnostic centre had copy deoxyribonucleic acid, derived from muscle ribonucleic acid, sequenced to identify variants with the potential to be responsible for the MH phenotype in both RYR1 and CACNA1S. These genetic findings were combined with clinical episode details and in vitro contracture test results to improve our understanding of the Australian MH cohort. Twelve novel variants were identified in RYR1 and six in CACNA1S. Known RYR1 causative mutations were identified in six persons and novel variants in RYR1 and CACNA1S in a further 17 persons. Trends indicated higher mutation identification in those with more definitive clinical episodes and stronger in vitro contracture test responses.
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Affiliation(s)
- R L Gillies
- Department of Anaesthesia and Pain Management, Royal Melbourne Hospital, Parkville, Victoria
| | - A R Bjorksten
- Department of Anaesthesia and Pain Management, Royal Melbourne Hospital, Parkville, Victoria
| | - D Du Sart
- Victorian Clinical Genetics Services, Parkville, Victoria
| | - B M Hockey
- Department of Anaesthesia and Pain Management, Royal Melbourne Hospital, Parkville, Victoria
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50
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Ca(2+) permeation and/or binding to CaV1.1 fine-tunes skeletal muscle Ca(2+) signaling to sustain muscle function. Skelet Muscle 2015; 5:4. [PMID: 25717360 PMCID: PMC4340672 DOI: 10.1186/s13395-014-0027-1] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2014] [Accepted: 12/11/2014] [Indexed: 11/13/2022] Open
Abstract
Background Ca2+ influx through CaV1.1 is not required for skeletal muscle excitation-contraction coupling, but whether Ca2+ permeation through CaV1.1 during sustained muscle activity plays a functional role in mammalian skeletal muscle has not been assessed. Methods We generated a mouse with a Ca2+ binding and/or permeation defect in the voltage-dependent Ca2+ channel, CaV1.1, and used Ca2+ imaging, western blotting, immunohistochemistry, proximity ligation assays, SUnSET analysis of protein synthesis, and Ca2+ imaging techniques to define pathways modulated by Ca2+ binding and/or permeation of CaV1.1. We also assessed fiber type distributions, cross-sectional area, and force frequency and fatigue in isolated muscles. Results Using mice with a pore mutation in CaV1.1 required for Ca2+ binding and/or permeation (E1014K, EK), we demonstrate that CaV1.1 opening is coupled to CaMKII activation and refilling of sarcoplasmic reticulum Ca2+ stores during sustained activity. Decreases in these Ca2+-dependent enzyme activities alter downstream signaling pathways (Ras/Erk/mTORC1) that lead to decreased muscle protein synthesis. The physiological consequences of the permeation and/or Ca2+ binding defect in CaV1.1 are increased fatigue, decreased fiber size, and increased Type IIb fibers. Conclusions While not essential for excitation-contraction coupling, Ca2+ binding and/or permeation via the CaV1.1 pore plays an important modulatory role in muscle performance. Electronic supplementary material The online version of this article (doi:10.1186/s13395-014-0027-1) contains supplementary material, which is available to authorized users.
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