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Li A, Yi J, Li X, Dong L, Ostrow LW, Ma J, Zhou J. Distinct transcriptomic profile of satellite cells contributes to preservation of neuromuscular junctions in extraocular muscles of ALS mice. eLife 2024; 12:RP92644. [PMID: 38661532 PMCID: PMC11045223 DOI: 10.7554/elife.92644] [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: 04/26/2024] Open
Abstract
Amyotrophic lateral sclerosis (ALS) is a fatal neuromuscular disorder characterized by progressive weakness of almost all skeletal muscles, whereas extraocular muscles (EOMs) are comparatively spared. While hindlimb and diaphragm muscles of end-stage SOD1G93A (G93A) mice (a familial ALS mouse model) exhibit severe denervation and depletion of Pax7+satellite cells (SCs), we found that the pool of SCs and the integrity of neuromuscular junctions (NMJs) are maintained in EOMs. In cell sorting profiles, SCs derived from hindlimb and diaphragm muscles of G93A mice exhibit denervation-related activation, whereas SCs from EOMs of G93A mice display spontaneous (non-denervation-related) activation, similar to SCs from wild-type mice. Specifically, cultured EOM SCs contain more abundant transcripts of axon guidance molecules, including Cxcl12, along with more sustainable renewability than the diaphragm and hindlimb counterparts under differentiation pressure. In neuromuscular co-culture assays, AAV-delivery of Cxcl12 to G93A-hindlimb SC-derived myotubes enhances motor neuron axon extension and innervation, recapitulating the innervation capacity of EOM SC-derived myotubes. G93A mice fed with sodium butyrate (NaBu) supplementation exhibited less NMJ loss in hindlimb and diaphragm muscles. Additionally, SCs derived from G93A hindlimb and diaphragm muscles displayed elevated expression of Cxcl12 and improved renewability following NaBu treatment in vitro. Thus, the NaBu-induced transcriptomic changes resembling the patterns of EOM SCs may contribute to the beneficial effects observed in G93A mice. More broadly, the distinct transcriptomic profile of EOM SCs may offer novel therapeutic targets to slow progressive neuromuscular functional decay in ALS and provide possible 'response biomarkers' in pre-clinical and clinical studies.
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Affiliation(s)
- Ang Li
- Department of Kinesiology, College of Nursing and Health Innovation, The University of Texas at ArlingtonArlingtonUnited States
| | - Jianxun Yi
- Department of Kinesiology, College of Nursing and Health Innovation, The University of Texas at ArlingtonArlingtonUnited States
| | - Xuejun Li
- Department of Kinesiology, College of Nursing and Health Innovation, The University of Texas at ArlingtonArlingtonUnited States
| | - Li Dong
- Department of Kinesiology, College of Nursing and Health Innovation, The University of Texas at ArlingtonArlingtonUnited States
| | - Lyle W Ostrow
- Department of Neurology, Lewis Katz School of Medicine at Temple UniversityPhiladelphiaUnited States
| | - Jianjie Ma
- Department of Surgery, Division of Surgical Sciences, University of VirginiaCharlottesvilleUnited States
| | - Jingsong Zhou
- Department of Kinesiology, College of Nursing and Health Innovation, The University of Texas at ArlingtonArlingtonUnited States
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2
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Benucci S, Ruiz A, Franchini M, Ruggiero L, Zoppi D, Sitsapesan R, Lindsay C, Pelczar P, Pietrangelo L, Protasi F, Treves S, Zorzato F. A novel, patient-derived RyR1 mutation impairs muscle function and calcium homeostasis in mice. J Gen Physiol 2024; 156:e202313486. [PMID: 38445312 PMCID: PMC10911087 DOI: 10.1085/jgp.202313486] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2023] [Revised: 12/20/2023] [Accepted: 02/09/2024] [Indexed: 03/07/2024] Open
Abstract
RYR1 is the most commonly mutated gene associated with congenital myopathies, a group of early-onset neuromuscular conditions of variable severity. The functional effects of a number of dominant RYR1 mutations have been established; however, for recessive mutations, these effects may depend on multiple factors, such as the formation of a hypomorphic allele, or on whether they are homozygous or compound heterozygous. Here, we functionally characterize a new transgenic mouse model knocked-in for mutations identified in a severely affected child born preterm and presenting limited limb movement. The child carried the homozygous c.14928C>G RYR1 mutation, resulting in the p.F4976L substitution. In vivo and ex vivo assays revealed that homozygous mice fatigued sooner and their muscles generated significantly less force compared with their WT or heterozygous littermates. Electron microscopy, biochemical, and physiological analyses showed that muscles from RyR1 p.F4976L homozygous mice have the following properties: (1) contain fewer calcium release units and show areas of myofibrillar degeneration, (2) contain less RyR1 protein, (3) fibers show smaller electrically evoked calcium transients, and (4) their SR has smaller calcium stores. In addition, single-channel recordings indicate that RyR1 p.F4976L exhibits higher Po in the presence of 100 μM [Ca2+]. Our mouse model partly recapitulates the clinical picture of the homozygous human patient and provides significant insight into the functional impact of this mutation. These results will help understand the pathology of patients with similar RYR1 mutations.
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Affiliation(s)
- Sofia Benucci
- Departments of Biomedicine and Neurology, Basel University Hospital, Basel, Switzerland
| | - Alexis Ruiz
- Departments of Biomedicine and Neurology, Basel University Hospital, Basel, Switzerland
| | - Martina Franchini
- Departments of Biomedicine and Neurology, Basel University Hospital, Basel, Switzerland
| | - Lucia Ruggiero
- Dipartimento di Neuroscienze, Scienze Riproduttive ed Odontostomatologiche, Università degli Studi di Napoli Federico II, Napoli, Italy
| | - Dario Zoppi
- Dipartimento di Neuroscienze, Scienze Riproduttive ed Odontostomatologiche, Università degli Studi di Napoli Federico II, Napoli, Italy
| | | | - Chris Lindsay
- Department of Pharmacology, University of Oxford, Oxford, UK
| | - Pawel Pelczar
- Center for Transgenic Models, University of Basel, Basel, Switzerland
| | - Laura Pietrangelo
- DMSI, Department of Medicine and Aging Sciences and CAST, Center for Advanced Studies and Technology, University G. d’Annunzio of Chieti-Pescara, Chieti, Italy
| | - Feliciano Protasi
- DMSI, Department of Medicine and Aging Sciences and CAST, Center for Advanced Studies and Technology, University G. d’Annunzio of Chieti-Pescara, Chieti, Italy
| | - Susan Treves
- Departments of Biomedicine and Neurology, Basel University Hospital, Basel, Switzerland
- Department of Life Science and Biotechnology, University of Ferrara, Ferrara, Italy
| | - Francesco Zorzato
- Departments of Biomedicine and Neurology, Basel University Hospital, Basel, Switzerland
- Department of Life Science and Biotechnology, University of Ferrara, Ferrara, Italy
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Knutson KR, Whiteman ST, Alcaino C, Mercado-Perez A, Finholm I, Serlin HK, Bellampalli SS, Linden DR, Farrugia G, Beyder A. Intestinal enteroendocrine cells rely on ryanodine and IP 3 calcium store receptors for mechanotransduction. J Physiol 2023; 601:287-305. [PMID: 36428286 PMCID: PMC9840706 DOI: 10.1113/jp283383] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2022] [Accepted: 11/24/2022] [Indexed: 11/27/2022] Open
Abstract
Enteroendocrine cells (EECs) are specialized sensors of luminal forces and chemicals in the gastrointestinal (GI) epithelium that respond to stimulation with a release of signalling molecules such as serotonin (5-HT). For mechanosensitive EECs, force activates Piezo2 channels, which generate a very rapidly activating and inactivating (∼10 ms) cationic (Na+ , K+ , Ca2+ ) receptor current. Piezo2 receptor currents lead to a large and persistent increase in intracellular calcium (Ca2+ ) that lasts many seconds to sometimes minutes, suggesting signal amplification. However, intracellular calcium dynamics in EEC mechanotransduction remain poorly understood. The aim of this study was to determine the role of Ca2+ stores in EEC mechanotransduction. Mechanical stimulation of a human EEC cell model (QGP-1) resulted in a rapid increase in cytoplasmic Ca2+ and a slower decrease in ER stores Ca2+ , suggesting the involvement of intracellular Ca2+ stores. Comparing murine primary colonic EECs with colonocytes showed expression of intercellular Ca2+ store receptors, a similar expression of IP3 receptors, but a >30-fold enriched expression of Ryr3 in EECs. In mechanically stimulated primary EECs, Ca2+ responses decreased dramatically by emptying stores and pharmacologically blocking IP3 and RyR1/3 receptors. RyR3 genetic knockdown by siRNA led to a significant decrease in mechanosensitive Ca2+ responses and 5-HT release. In tissue, pressure-induced increase in the Ussing short circuit current was significantly decreased by ryanodine receptor blockade. Our data show that mechanosensitive EECs use intracellular Ca2+ stores to amplify mechanically induced Ca2+ entry, with RyR3 receptors selectively expressed in EECs and involved in Ca2+ signalling, 5-HT release and epithelial secretion. KEY POINTS: A population of enteroendocrine cells (EECs) are specialized mechanosensors of the gastrointestinal (GI) epithelium that respond to mechanical stimulation with the release of important signalling molecules such as serotonin. Mechanical activation of these EECs leads to an increase in intracellular calcium (Ca2+ ) with a longer duration than the stimulus, suggesting intracellular Ca2+ signal amplification. In this study, we profiled the expression of intracellular Ca2+ store receptors and found an enriched expression of the intracellular Ca2+ receptor Ryr3, which contributed to the mechanically evoked increases in intracellular calcium, 5-HT release and epithelial secretion. Our data suggest that mechanosensitive EECs rely on intracellular Ca2+ stores and are selective in their use of Ryr3 for amplification of intracellular Ca2+ . This work advances our understanding of EEC mechanotransduction and may provide novel diagnostic and therapeutic targets for GI motility disorders.
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Affiliation(s)
- Kaitlyn R. Knutson
- Enteric Neuroscience Program (ENSP), Mayo Clinic, Rochester, Minnesota
- Department of Physiology & Biomedical Engineering, Mayo Clinic, Rochester, Minnesota
| | - Sara T. Whiteman
- Enteric Neuroscience Program (ENSP), Mayo Clinic, Rochester, Minnesota
- Department of Physiology & Biomedical Engineering, Mayo Clinic, Rochester, Minnesota
| | - Constanza Alcaino
- Enteric Neuroscience Program (ENSP), Mayo Clinic, Rochester, Minnesota
- Department of Physiology & Biomedical Engineering, Mayo Clinic, Rochester, Minnesota
| | - Arnaldo Mercado-Perez
- Enteric Neuroscience Program (ENSP), Mayo Clinic, Rochester, Minnesota
- Department of Physiology & Biomedical Engineering, Mayo Clinic, Rochester, Minnesota
- Medical Scientist Training Program (MSTP), Mayo Clinic, Rochester, Minnesota
| | - Isabelle Finholm
- Enteric Neuroscience Program (ENSP), Mayo Clinic, Rochester, Minnesota
- Department of Physiology & Biomedical Engineering, Mayo Clinic, Rochester, Minnesota
| | - Hannah K. Serlin
- Enteric Neuroscience Program (ENSP), Mayo Clinic, Rochester, Minnesota
- Department of Physiology & Biomedical Engineering, Mayo Clinic, Rochester, Minnesota
| | - Shreya S. Bellampalli
- Enteric Neuroscience Program (ENSP), Mayo Clinic, Rochester, Minnesota
- Department of Physiology & Biomedical Engineering, Mayo Clinic, Rochester, Minnesota
- Medical Scientist Training Program (MSTP), Mayo Clinic, Rochester, Minnesota
| | - David R. Linden
- Enteric Neuroscience Program (ENSP), Mayo Clinic, Rochester, Minnesota
- Department of Physiology & Biomedical Engineering, Mayo Clinic, Rochester, Minnesota
| | - Gianrico Farrugia
- Enteric Neuroscience Program (ENSP), Mayo Clinic, Rochester, Minnesota
- Division of Gastroenterology &Hepatology, Department of Medicine, Mayo Clinic, Rochester, Minnesota
- Department of Physiology & Biomedical Engineering, Mayo Clinic, Rochester, Minnesota
| | - Arthur Beyder
- Enteric Neuroscience Program (ENSP), Mayo Clinic, Rochester, Minnesota
- Division of Gastroenterology &Hepatology, Department of Medicine, Mayo Clinic, Rochester, Minnesota
- Department of Physiology & Biomedical Engineering, Mayo Clinic, Rochester, Minnesota
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Lian H, Qin Z, Wu M, Zuo P, Bai L, Lu M, Li L, Zhang H. Contractility detection of isolated mouse papillary muscle using myotronic Myostation-Intact device. Animal Model Exp Med 2022; 5:445-452. [PMID: 36168142 PMCID: PMC9610137 DOI: 10.1002/ame2.12272] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2022] [Accepted: 08/29/2022] [Indexed: 11/06/2022] Open
Abstract
Background To understand the relationship between myocardial contractility and external stimuli, detecting ex vivo myocardial contractility is necessary. Methods We elaborated a method for contractility detection of isolated C57 mouse papillary muscle using Myostation‐Intact system under different frequencies, voltages, and calcium concentrations. Results The results indicated that the basal contractility of the papillary muscle was 0.27 ± 0.03 mN at 10 V, 500‐ms pulse duration, and 1 Hz. From 0.1 to 1.0 Hz, contractility decreased with an increase in frequency (0.45 ± 0.11–0.10 ± 0.02 mN). The voltage‐initiated muscle contractility varied from 3 to 6 V, and the contractility gradually increased as the voltage increased from 6 to 10 V (0.14 ± 0.02–0.28 ± 0.03 mN). Moreover, the muscle contractility increased when the calcium concentration was increased from 1.5 to 3 mM (0.45 ± 0.17–1.11 ± 0.05 mN); however, the contractility stopped increasing even when the concentration was increased to 7.5 mM (1.02 ± 0.23 mN). Conclusions Our method guaranteed the survivability of papillary muscle ex vivo and provided instructions for Myostation‐Intact users for isolated muscle contractility investigations.
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Affiliation(s)
- Hong Lian
- State Key Laboratory of Cardiovascular Disease, Fuwai Hospital, National Center for Cardiovascular Disease, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China.,Beijing Key Laboratory of Preclinical Research and Evaluation for Cardiovascular Implant Materials, Animal Experimental Center, Fuwai Hospital, National Center for Cardiovascular Disease, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Zhuyun Qin
- State Key Laboratory of Cardiovascular Disease, Fuwai Hospital, National Center for Cardiovascular Disease, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China.,Adult Surgical Intensive Care Unit, Fuwai Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Mengge Wu
- National Health Commission Key Laboratory of Cardiovascular Regenerative Medicine, Fuwai Central-China Hospital, Central-China Subcenter of National Center for Cardiovascular Diseases, Zhengzhou, China
| | - Peipei Zuo
- National Health Commission Key Laboratory of Cardiovascular Regenerative Medicine, Fuwai Central-China Hospital, Central-China Subcenter of National Center for Cardiovascular Diseases, Zhengzhou, China
| | - Lina Bai
- State Key Laboratory of Cardiovascular Disease, Fuwai Hospital, National Center for Cardiovascular Disease, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Minjie Lu
- State Key Laboratory of Cardiovascular Disease, Fuwai Hospital, National Center for Cardiovascular Disease, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Lulu Li
- State Key Laboratory of Cardiovascular Disease, Fuwai Hospital, National Center for Cardiovascular Disease, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China.,Adult Surgical Intensive Care Unit, Fuwai Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Haitao Zhang
- Adult Surgical Intensive Care Unit, Fuwai Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
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Imaizumi Y. Reciprocal Relationship between Ca 2+ Signaling and Ca 2+-Gated Ion Channels as a Potential Target for Drug Discovery. Biol Pharm Bull 2022; 45:1-18. [PMID: 34980771 DOI: 10.1248/bpb.b21-00896] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Cellular Ca2+ signaling functions as one of the most common second messengers of various signal transduction pathways in cells and mediates a number of physiological roles in a cell-type dependent manner. Ca2+ signaling also regulates more general and fundamental cellular activities, including cell proliferation and apoptosis. Among ion channels, Ca2+-permeable channels in the plasma membrane as well as endo- and sarcoplasmic reticulum membranes play important roles in Ca2+ signaling by directly contributing to the influx of Ca2+ from extracellular spaces or its release from storage sites, respectively. Furthermore, Ca2+-gated ion channels in the plasma membrane often crosstalk reciprocally with Ca2+ signals and are central to the regulation of cellular functions. This review focuses on the physiological and pharmacological impact of i) Ca2+-gated ion channels as an apparatus for the conversion of cellular Ca2+ signals to intercellularly propagative electrical signals and ii) the opposite feedback regulation of Ca2+ signaling by Ca2+-gated ion channel activities in excitable and non-excitable cells.
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Affiliation(s)
- Yuji Imaizumi
- Department of Molecular and Cellular Pharmacology, Graduate School of Pharmaceutical Sciences, Nagoya City University
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Beaufils M, Travard L, Rendu J, Marty I. Therapies for RYR1-Related Myopathies: Where We Stand and the Perspectives. Curr Pharm Des 2021; 28:15-25. [PMID: 34514983 DOI: 10.2174/1389201022666210910102516] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2021] [Accepted: 08/13/2021] [Indexed: 11/22/2022]
Abstract
RyR1-related myopathies are a family of genetic neuromuscular diseases due to mutations in the RYR1 gene. No treatment exists for any of these myopathies today, which could change in the coming years with the growing number of studies dedicated to the pre-clinical assessment of various approaches, from pharmacological to gene therapy strategies, using the numerous models developed up to now. In addition, the first clinical trials for these rare diseases have just been completed or are being launched. We review the most recent results obtained for the treatment of RyR1-related myopathies, and, in view of the progress in therapeutic development for other myopathies, we discuss the possible future therapeutic perspectives for RyR1-related myopathies.
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Affiliation(s)
- Mathilde Beaufils
- University Grenoble Alpes, INSERM, U1216, CHU Grenoble Alpes, Grenoble Institut Neurosciences, Grenoble. France
| | - Lauriane Travard
- University Grenoble Alpes, INSERM, U1216, CHU Grenoble Alpes, Grenoble Institut Neurosciences, Grenoble. France
| | - John Rendu
- University Grenoble Alpes, INSERM, U1216, CHU Grenoble Alpes, Grenoble Institut Neurosciences, Grenoble. France
| | - Isabelle Marty
- University Grenoble Alpes, INSERM, U1216, CHU Grenoble Alpes, Grenoble Institut Neurosciences, Grenoble. France
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Eckhardt J, Bachmann C, Benucci S, Elbaz M, Ruiz A, Zorzato F, Treves S. Molecular basis of impaired extraocular muscle function in a mouse model of congenital myopathy due to compound heterozygous Ryr1 mutations. Hum Mol Genet 2021; 29:1330-1339. [PMID: 32242214 DOI: 10.1093/hmg/ddaa056] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2020] [Revised: 03/25/2020] [Accepted: 03/31/2020] [Indexed: 01/20/2023] Open
Abstract
Mutations in the RYR1 gene are the most common cause of human congenital myopathies, and patients with recessive mutations are severely affected and often display ptosis and/or ophthalmoplegia. In order to gain insight into the mechanism leading to extraocular muscle (EOM) involvement, we investigated the biochemical, structural and physiological properties of eye muscles from mouse models we created knocked-in for Ryr1 mutations. Ex vivo force production in EOMs from compound heterozygous RyR1p.Q1970fsX16+p.A4329D mutant mice was significantly reduced compared with that observed in wild-type, single heterozygous mutant carriers or homozygous RyR1p.A4329D mice. The decrease in muscle force was also accompanied by approximately a 40% reduction in RyR1 protein content, a decrease in electrically evoked calcium transients, disorganization of the muscle ultrastructure and a decrease in the number of calcium release units. Unexpectedly, the superfast and ocular-muscle-specific myosin heavy chain-EO isoform was almost undetectable in RyR1p.Q1970fsX16+p.A4329D mutant mice. The results of this study show for the first time that the EOM phenotype caused by the RyR1p.Q1970fsX16+p.A4329D compound heterozygous Ryr1 mutations is complex and due to a combination of modifications including a direct effect on the macromolecular complex involved in calcium release and indirect effects on the expression of myosin heavy chain isoforms.
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Affiliation(s)
- Jan Eckhardt
- Departments of Biomedicine, Basel University Hospital, 4031 Basel, Switzerland
| | - Christoph Bachmann
- Departments of Biomedicine, Basel University Hospital, 4031 Basel, Switzerland
| | - Sofia Benucci
- Departments of Biomedicine, Basel University Hospital, 4031 Basel, Switzerland
| | - Moran Elbaz
- Departments of Biomedicine, Basel University Hospital, 4031 Basel, Switzerland
| | - Alexis Ruiz
- Departments of Biomedicine, Basel University Hospital, 4031 Basel, Switzerland
| | - Francesco Zorzato
- Departments of Biomedicine, Basel University Hospital, 4031 Basel, Switzerland.,Department of Life Science and Biotechnology, University of Ferrara, 44100 Ferrara, Italy
| | - Susan Treves
- Departments of Biomedicine, Basel University Hospital, 4031 Basel, Switzerland.,Department of Life Science and Biotechnology, University of Ferrara, 44100 Ferrara, Italy
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Abstract
We sought to review the effects of statins on the ryanodine receptor (RyR) and on RyR-associated diseases, with an emphasis on catecholaminergic polymorphic ventricular tachycardia (CPVT). Statins can affect skeletal muscle and produce statin-associated muscle symptoms (SAMS) but have no adverse effects on cardiac muscle. These contrasting effects may be due to differences in how statins affect the skeletal (RyR1) and cardiac (RyR2) RyR. We searched PubMed to identify English language articles reporting the pathophysiology of the RyR, the effect of statins on RyR function, and on RyR-associated genetic diseases. We selected 150 articles for abstract review, 96 of which provided sufficient information to be included and were reviewed in detail. Fifteen articles highlighted the interaction of statins with the RyR. Nine identified the interaction of statins with RyR1, six addressed the interaction of statins with RyR2, 13 suggested that statins reduce ventricular arrhythmias (VA), and seven suggested that statins increase the risk of malignant hyperthermia (MH). In general, statins increase RyR1 and decrease RyR2 activity. We identified no articles examining the effect of statins on CPVT, a condition often caused by defects in RyR2. Statins appear to increase the risk of MH and decrease the risk of ventricular arrhythmia. The effect of statins on CPVT has not been directly examined, but statins' reduction in RyR2 function and their apparent reduction in VA suggest that they may be beneficial in this condition.
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Affiliation(s)
- Mohsin Haseeb
- Division of Cardiology, Loyola University Medical Center, Maywood, Illinois
| | - Paul D Thompson
- Division of Cardiology, Hartford Hospital, Hartford, Connecticut
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10
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Ca 2+ Channels Mediate Bidirectional Signaling between Sarcolemma and Sarcoplasmic Reticulum in Muscle Cells. Cells 2019; 9:cells9010055. [PMID: 31878335 PMCID: PMC7016941 DOI: 10.3390/cells9010055] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2019] [Revised: 12/19/2019] [Accepted: 12/23/2019] [Indexed: 12/21/2022] Open
Abstract
The skeletal muscle and myocardial cells present highly specialized structures; for example, the close interaction between the sarcoplasmic reticulum (SR) and mitochondria—responsible for excitation-metabolism coupling—and the junction that connects the SR with T-tubules, critical for excitation-contraction (EC) coupling. The mechanisms that underlie EC coupling in these two cell types, however, are fundamentally distinct. They involve the differential expression of Ca2+ channel subtypes: CaV1.1 and RyR1 (skeletal), vs. CaV1.2 and RyR2 (cardiac). The CaV channels transform action potentials into elevations of cytosolic Ca2+, by activating RyRs and thus promoting SR Ca2+ release. The high levels of Ca2+, in turn, stimulate not only the contractile machinery but also the generation of mitochondrial reactive oxygen species (ROS). This forward signaling is reciprocally regulated by the following feedback mechanisms: Ca2+-dependent inactivation (of Ca2+ channels), the recruitment of Na+/Ca2+ exchanger activity, and oxidative changes in ion channels and transporters. Here, we summarize both well-established concepts and recent advances that have contributed to a better understanding of the molecular mechanisms involved in this bidirectional signaling.
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Abstract
JGP study shows that ryanodine receptor 3 is important for extraocular muscle function.
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