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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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2
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White R, Schiemann AH, Burling SM, Bjorksten A, Bulger T, Gillies R, Hopkins PM, Kamsteeg EJ, Machon RG, Massey S, Miller D, Perry M, Snoeck MM, Stephens J, Street N, van den Bersselaar LR, Stowell KM. Functional analysis of RYR1 variants in patients with confirmed susceptibility to malignant hyperthermia. Br J Anaesth 2022; 129:879-888. [DOI: 10.1016/j.bja.2022.08.029] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2022] [Revised: 08/20/2022] [Accepted: 08/22/2022] [Indexed: 11/02/2022] Open
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Rossi D, Catallo MR, Pierantozzi E, Sorrentino V. Mutations in proteins involved in E-C coupling and SOCE and congenital myopathies. J Gen Physiol 2022; 154:213407. [PMID: 35980353 PMCID: PMC9391951 DOI: 10.1085/jgp.202213115] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2022] [Revised: 07/15/2022] [Accepted: 07/21/2022] [Indexed: 11/24/2022] Open
Abstract
In skeletal muscle, Ca2+ necessary for muscle contraction is stored and released from the sarcoplasmic reticulum (SR), a specialized form of endoplasmic reticulum through the mechanism known as excitation–contraction (E-C) coupling. Following activation of skeletal muscle contraction by the E-C coupling mechanism, replenishment of intracellular stores requires reuptake of cytosolic Ca2+ into the SR by the activity of SR Ca2+-ATPases, but also Ca2+ entry from the extracellular space, through a mechanism called store-operated calcium entry (SOCE). The fine orchestration of these processes requires several proteins, including Ca2+ channels, Ca2+ sensors, and Ca2+ buffers, as well as the active involvement of mitochondria. Mutations in genes coding for proteins participating in E-C coupling and SOCE are causative of several myopathies characterized by a wide spectrum of clinical phenotypes, a variety of histological features, and alterations in intracellular Ca2+ balance. This review summarizes current knowledge on these myopathies and discusses available knowledge on the pathogenic mechanisms of disease.
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Affiliation(s)
- Daniela Rossi
- Department of Molecular and Developmental Medicine, University of Siena, Siena, Italy.,Interdepartmental Program of Molecular Diagnosis and Pathogenetic Mechanisms of Rare Genetic Diseases, Azienda Ospedaliero Universitaria Senese, Siena, Italy
| | - Maria Rosaria Catallo
- Department of Molecular and Developmental Medicine, University of Siena, Siena, Italy
| | - Enrico Pierantozzi
- Department of Molecular and Developmental Medicine, University of Siena, Siena, Italy
| | - Vincenzo Sorrentino
- Department of Molecular and Developmental Medicine, University of Siena, Siena, Italy.,Interdepartmental Program of Molecular Diagnosis and Pathogenetic Mechanisms of Rare Genetic Diseases, Azienda Ospedaliero Universitaria Senese, Siena, Italy
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4
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García-Castañeda M, Michelucci A, Zhao N, Malik S, Dirksen RT. Postdevelopmental knockout of Orai1 improves muscle pathology in a mouse model of Duchenne muscular dystrophy. J Gen Physiol 2022; 154:213383. [PMID: 35939054 PMCID: PMC9365874 DOI: 10.1085/jgp.202213081] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2022] [Accepted: 07/07/2022] [Indexed: 11/20/2022] Open
Abstract
Duchenne muscular dystrophy (DMD), an X-linked disorder caused by loss-of-function mutations in the dystrophin gene, is characterized by progressive muscle degeneration and weakness. Enhanced store-operated Ca2+ entry (SOCE), a Ca2+ influx mechanism coordinated by STIM1 sensors of luminal Ca2+ within the sarcoplasmic reticulum (SR) and Ca2+-permeable Orai1 channels in the sarcolemma, is proposed to contribute to Ca2+-mediated muscle damage in DMD. To directly determine the impact of Orai1-dependent SOCE on the dystrophic phenotype, we crossed mdx mice with tamoxifen-inducible, muscle-specific Orai1 knockout mice (mdx-Orai1 KO mice). Both constitutive and SOCE were significantly increased in flexor digitorum brevis fibers from mdx mice, while SOCE was absent in fibers from both Orai1 KO and mdx-Orai1 KO mice. Compared with WT mice, fibers from mdx mice exhibited (1) increased resting myoplasmic Ca2+ levels, (2) reduced total releasable Ca2+ store content, and (3) a prolonged rate of electrically evoked Ca2+ transient decay. These effects were partially normalized in fibers from mdx-Orai1 KO mice. Intact extensor digitorum longus muscles from mdx mice exhibited a significant reduction of maximal specific force, which was rescued in muscles from mdx-Orai1 KO mice. Finally, during exposure to consecutive eccentric contractions, muscles from mdx mice displayed a more pronounced decline in specific force compared with that of WT mice, which was also significantly attenuated by Orai1 ablation. Together, these results indicate that enhanced Orai1-dependent SOCE exacerbates the dystrophic phenotype and that Orai1 deficiency improves muscle pathology by both normalizing Ca2+ homeostasis and promoting sarcolemmal integrity/stability.
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Affiliation(s)
- Maricela García-Castañeda
- Department of Pharmacology and Physiology, University of Rochester School of Medicine and Dentistry, Rochester, NY
| | - Antonio Michelucci
- Department of Pharmacology and Physiology, University of Rochester School of Medicine and Dentistry, Rochester, NY,Department of Chemistry, Biology and Biotechnology, University of Perugia, Perugia, Italy
| | - Nan Zhao
- Department of Pharmacology and Physiology, University of Rochester School of Medicine and Dentistry, Rochester, NY
| | - Sundeep Malik
- Department of Pharmacology and Physiology, University of Rochester School of Medicine and Dentistry, Rochester, NY
| | - Robert T. Dirksen
- Department of Pharmacology and Physiology, University of Rochester School of Medicine and Dentistry, Rochester, NY
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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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Michelucci A, Boncompagni S, Pietrangelo L, Takano T, Protasi F, Dirksen RT. Pre-assembled Ca2+ entry units and constitutively active Ca2+ entry in skeletal muscle of calsequestrin-1 knockout mice. J Gen Physiol 2021; 152:152001. [PMID: 32761048 PMCID: PMC7537346 DOI: 10.1085/jgp.202012617] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2020] [Accepted: 07/15/2020] [Indexed: 12/13/2022] Open
Abstract
Store-operated Ca2+ entry (SOCE) is a ubiquitous Ca2+ influx mechanism triggered by depletion of Ca2+ stores from the endoplasmic/sarcoplasmic reticulum (ER/SR). We recently reported that acute exercise in WT mice drives the formation of Ca2+ entry units (CEUs), intracellular junctions that contain STIM1 and Orai1, the two key proteins mediating SOCE. The presence of CEUs correlates with increased constitutive- and store-operated Ca2+ entry, as well as sustained Ca2+ release and force generation during repetitive stimulation. Skeletal muscle from mice lacking calsequestrin-1 (CASQ1-null), the primary Ca2+-binding protein in the lumen of SR terminal cisternae, exhibits significantly reduced total Ca2+ store content and marked SR Ca2+ depletion during high-frequency stimulation. Here, we report that CEUs are constitutively assembled in extensor digitorum longus (EDL) and flexor digitorum brevis (FDB) muscles of sedentary CASQ1-null mice. The higher density of CEUs in EDL (39.6 ± 2.1/100 µm2 versus 2.0 ± 0.3/100 µm2) and FDB (16.7 ± 1.0/100 µm2 versus 2.7 ± 0.5/100 µm2) muscles of CASQ1-null compared with WT mice correlated with enhanced constitutive- and store-operated Ca2+ entry and increased expression of STIM1, Orai1, and SERCA. The higher ability to recover Ca2+ ions via SOCE in CASQ1-null muscle served to promote enhanced maintenance of peak Ca2+ transient amplitude, increased dependence of luminal SR Ca2+ replenishment on BTP-2-sensitive SOCE, and increased maintenance of contractile force during repetitive, high-frequency stimulation. Together, these data suggest that muscles from CASQ1-null mice compensate for the lack of CASQ1 and reduction in total releasable SR Ca2+ content by assembling CEUs to promote constitutive and store-operated Ca2+ entry.
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Affiliation(s)
- Antonio Michelucci
- Department of Pharmacology and Physiology, University of Rochester School of Medicine and Dentistry, Rochester, NY.,Center for Advanced Studies and Technologies, University G. d'Annunzio of Chieti, Chieti, Italy
| | - Simona Boncompagni
- Center for Advanced Studies and Technologies, University G. d'Annunzio of Chieti, Chieti, Italy.,Department of Neuroscience, Imaging and Clinical Sciences, University G. d'Annunzio of Chieti, Chieti, Italy
| | - Laura Pietrangelo
- Center for Advanced Studies and Technologies, University G. d'Annunzio of Chieti, Chieti, Italy.,Department of Neuroscience, Imaging and Clinical Sciences, University G. d'Annunzio of Chieti, Chieti, Italy
| | - Takahiro Takano
- Department of Pharmacology and Physiology, University of Rochester School of Medicine and Dentistry, Rochester, NY
| | - Feliciano Protasi
- Center for Advanced Studies and Technologies, University G. d'Annunzio of Chieti, Chieti, Italy.,Department of Medicine and Ageing Sciences, University G. d'Annunzio of Chieti, Chieti, Italy
| | - Robert T Dirksen
- Department of Pharmacology and Physiology, University of Rochester School of Medicine and Dentistry, Rochester, NY
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Hanna AD, Lee CS, Babcock L, Wang H, Recio J, Hamilton SL. Pathological mechanisms of vacuolar aggregate myopathy arising from a Casq1 mutation. FASEB J 2021; 35:e21349. [PMID: 33786938 DOI: 10.1096/fj.202001653rr] [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: 07/07/2020] [Revised: 12/15/2020] [Accepted: 12/22/2020] [Indexed: 11/11/2022]
Abstract
Mice with a mutation (D244G, DG) in calsequestrin 1 (CASQ1), analogous to a human mutation in CASQ1 associated with a delayed onset human myopathy (vacuolar aggregate myopathy), display a progressive myopathy characterized by decreased activity, decreased ability of fast twitch muscles to generate force and low body weight after one year of age. The DG mutation causes CASQ1 to partially dissociate from the junctional sarcoplasmic reticulum (SR) and accumulate in the endoplasmic reticulum (ER). Decreased junctional CASQ1 reduces SR Ca2+ release. Muscles from older DG mice display ER stress, ER expansion, increased mTOR signaling, inadequate clearance of aggregated proteins by the proteasomes, and elevation of protein aggregates and lysosomes. This study suggests that the myopathy associated with the D244G mutation in CASQ1 is driven by CASQ1 mislocalization, reduced SR Ca2+ release, CASQ1 misfolding/aggregation and ER stress. The subsequent maladaptive increase in protein synthesis and decreased protein aggregate clearance are likely to contribute to disease progression.
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Affiliation(s)
- Amy D Hanna
- Department of Molecular Physiology and Biophysics, Baylor College of Medicine, Houston, TX, USA
| | - Chang Seok Lee
- Department of Molecular Physiology and Biophysics, Baylor College of Medicine, Houston, TX, USA
| | - Lyle Babcock
- Department of Molecular Physiology and Biophysics, Baylor College of Medicine, Houston, TX, USA
| | - Hui Wang
- Department of Molecular Physiology and Biophysics, Baylor College of Medicine, Houston, TX, USA
| | - Joseph Recio
- Department of Molecular Physiology and Biophysics, Baylor College of Medicine, Houston, TX, USA
| | - Susan L Hamilton
- Department of Molecular Physiology and Biophysics, Baylor College of Medicine, Houston, TX, USA
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Lawal TA, Todd JJ, Witherspoon JW, Bönnemann CG, Dowling JJ, Hamilton SL, Meilleur KG, Dirksen RT. Ryanodine receptor 1-related disorders: an historical perspective and proposal for a unified nomenclature. Skelet Muscle 2020; 10:32. [PMID: 33190635 PMCID: PMC7667763 DOI: 10.1186/s13395-020-00243-4] [Citation(s) in RCA: 41] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2020] [Accepted: 08/18/2020] [Indexed: 12/14/2022] Open
Abstract
The RYR1 gene, which encodes the sarcoplasmic reticulum calcium release channel or type 1 ryanodine receptor (RyR1) of skeletal muscle, was sequenced in 1988 and RYR1 variations that impair calcium homeostasis and increase susceptibility to malignant hyperthermia were first identified in 1991. Since then, RYR1-related myopathies (RYR1-RM) have been described as rare, histopathologically and clinically heterogeneous, and slowly progressive neuromuscular disorders. RYR1 variants can lead to dysfunctional RyR1-mediated calcium release, malignant hyperthermia susceptibility, elevated oxidative stress, deleterious post-translational modifications, and decreased RyR1 expression. RYR1-RM-affected individuals can present with delayed motor milestones, contractures, scoliosis, ophthalmoplegia, and respiratory insufficiency. Historically, RYR1-RM-affected individuals were diagnosed based on morphologic features observed in muscle biopsies including central cores, cores and rods, central nuclei, fiber type disproportion, and multi-minicores. However, these histopathologic features are not always specific to RYR1-RM and often change over time. As additional phenotypes were associated with RYR1 variations (including King-Denborough syndrome, exercise-induced rhabdomyolysis, lethal multiple pterygium syndrome, adult-onset distal myopathy, atypical periodic paralysis with or without myalgia, mild calf-predominant myopathy, and dusty core disease) the overlap among diagnostic categories is ever increasing. With the continuing emergence of new clinical subtypes along the RYR1 disease spectrum and reports of adult-onset phenotypes, nuanced nomenclatures have been reported (RYR1- [related, related congenital, congenital] myopathies). In this narrative review, we provide historical highlights of RYR1 research, accounts of the main diagnostic disease subtypes and propose RYR1-related disorders (RYR1-RD) as a unified nomenclature to describe this complex and evolving disease spectrum.
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Affiliation(s)
- Tokunbor A Lawal
- Tissue Injury Branch, National Institute of Nursing Research, National Institutes of Health, Bethesda, MD, USA.
| | - Joshua J Todd
- Tissue Injury Branch, National Institute of Nursing Research, National Institutes of Health, Bethesda, MD, USA
| | - Jessica W Witherspoon
- Tissue Injury Branch, National Institute of Nursing Research, National Institutes of Health, Bethesda, MD, USA
| | - Carsten G Bönnemann
- Neurogenetics Branch, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, USA
| | - James J Dowling
- Departments of Paediatrics and Molecular Genetics, Hospital for Sick Children and University of Toronto, Toronto, Canada
| | - Susan L Hamilton
- Molecular Physiology & Biophysics, Baylor College of Medicine, Houston, TX, USA
| | - Katherine G Meilleur
- Tissue Injury Branch, National Institute of Nursing Research, National Institutes of Health, Bethesda, MD, USA
| | - Robert T Dirksen
- Department of Pharmacology and Physiology, University of Rochester Medical Center, Rochester, NY, USA
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10
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Lawal TA, Wires ES, Terry NL, Dowling JJ, Todd JJ. Preclinical model systems of ryanodine receptor 1-related myopathies and malignant hyperthermia: a comprehensive scoping review of works published 1990-2019. Orphanet J Rare Dis 2020; 15:113. [PMID: 32381029 PMCID: PMC7204063 DOI: 10.1186/s13023-020-01384-x] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2019] [Accepted: 04/14/2020] [Indexed: 02/07/2023] Open
Abstract
BACKGROUND Pathogenic variations in the gene encoding the skeletal muscle ryanodine receptor (RyR1) are associated with malignant hyperthermia (MH) susceptibility, a life-threatening hypermetabolic condition and RYR1-related myopathies (RYR1-RM), a spectrum of rare neuromuscular disorders. In RYR1-RM, intracellular calcium dysregulation, post-translational modifications, and decreased protein expression lead to a heterogenous clinical presentation including proximal muscle weakness, contractures, scoliosis, respiratory insufficiency, and ophthalmoplegia. Preclinical model systems of RYR1-RM and MH have been developed to better understand underlying pathomechanisms and test potential therapeutics. METHODS We conducted a comprehensive scoping review of scientific literature pertaining to RYR1-RM and MH preclinical model systems in accordance with the PRISMA Scoping Reviews Checklist and the framework proposed by Arksey and O'Malley. Two major electronic databases (PubMed and EMBASE) were searched without language restriction for articles and abstracts published between January 1, 1990 and July 3, 2019. RESULTS Our search yielded 5049 publications from which 262 were included in this review. A majority of variants tested in RYR1 preclinical models were localized to established MH/central core disease (MH/CCD) hot spots. A total of 250 unique RYR1 variations were reported in human/rodent/porcine models with 95% being missense substitutions. The most frequently reported RYR1 variant was R614C/R615C (human/porcine total n = 39), followed by Y523S/Y524S (rabbit/mouse total n = 30), I4898T/I4897T/I4895T (human/rabbit/mouse total n = 20), and R163C/R165C (human/mouse total n = 18). The dyspedic mouse was utilized by 47% of publications in the rodent category and its RyR1-null (1B5) myotubes were transfected in 23% of publications in the cellular model category. In studies of transfected HEK-293 cells, 57% of RYR1 variations affected the RyR1 channel and activation core domain. A total of 15 RYR1 mutant mouse strains were identified of which ten were heterozygous, three were compound heterozygous, and a further two were knockout. Porcine, avian, zebrafish, C. elegans, canine, equine, and drosophila model systems were also reported. CONCLUSIONS Over the past 30 years, there were 262 publications on MH and RYR1-RM preclinical model systems featuring more than 200 unique RYR1 variations tested in a broad range of species. Findings from these studies have set the foundation for therapeutic development for MH and RYR1-RM.
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Affiliation(s)
- Tokunbor A Lawal
- National Institute of Nursing Research, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Emily S Wires
- National Institute on Drug Abuse, National Institutes of Health, Baltimore, MD, USA
| | - Nancy L Terry
- National Institutes of Health Library, National Institutes of Health, Bethesda, MD, USA
| | - James J Dowling
- Program for Genetics and Genome Biology, Hospital for Sick Children, Toronto, Ontario, Canada
| | - Joshua J Todd
- National Institute of Nursing Research, National Institutes of Health, Bethesda, MD, 20892, USA.
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Graham B, Shaw MA, Hope IA. Single Amino Acid Changes in the Ryanodine Receptor in the Human Population Have Effects In Vivo on Caenorhabditis elegans Neuro-Muscular Function. Front Genet 2020; 11:37. [PMID: 32174957 PMCID: PMC7054344 DOI: 10.3389/fgene.2020.00037] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2019] [Accepted: 01/13/2020] [Indexed: 01/21/2023] Open
Abstract
The ryanodine receptor mediates intracellular calcium ion release with excitation of nerve and muscle cells. Ryanodine receptor missense variants cause a number of myopathologies, such as malignant hyperthermia, and have been linked with various neuropathologies, including Alzheimer's disease. We characterized the consequences of ryanodine receptor variants in vivo. Eight Caenorhabditis elegans strains, with ryanodine receptor modifications equivalent to human myopathic RYR1 variants, were generated by genome editing. In humans, these variants are rare and confer sensitivity to the inhalational anaesthetic halothane when heterozygous. Increased sensitivity to halothane was found in both homozygous and heterozygous C. elegans. Close analysis revealed distinct subtle locomotion defects, due to the different single amino acid residue changes, even in the absence of the external triggering agent. Distinct pre- and postsynaptic consequences of the variants were characterized through the responses to cholinergic pharmacological agents. The range of phenotypes reflects the complexity of the regulatory inputs to the ryanodine receptor and the criticality of the calcium ion channel opening properties, in different cell types and with age. Ryanodine receptors with these single amino acid residue changes still function as calcium ion channels, but with altered properties which are likely to have subtle consequences for human carriers of such variants. The long-term consequences of subtly altered calcium ion signalling could be cumulative and may be focussed in the smaller nerve cells rather than the more robust muscle cells. It was important to assess phenotypes in vivo to properly appreciate consequences for a whole organism.
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Affiliation(s)
- Brittany Graham
- School of Biology, Faculty of Biological Sciences, University of Leeds, Leeds, United Kingdom
| | - Marie-Anne Shaw
- Leeds Institute of Medical Research, St James’s University Hospital, Leeds, United Kingdom
| | - Ian A. Hope
- School of Biology, Faculty of Biological Sciences, University of Leeds, Leeds, United Kingdom
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Xu L, Harms FL, Chirasani VR, Pasek DA, Kortüm F, Meinecke P, Dokholyan NV, Kutsche K, Meissner G. Single-channel properties of skeletal muscle ryanodine receptor pore Δ 4923FF 4924 in two brothers with a lethal form of fetal akinesia. Cell Calcium 2020; 87:102182. [PMID: 32097819 DOI: 10.1016/j.ceca.2020.102182] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2019] [Revised: 02/14/2020] [Accepted: 02/14/2020] [Indexed: 11/26/2022]
Abstract
Ryanodine receptor ion channels (RyR1s) release Ca2+ ions from the sarcoplasmic reticulum to regulate skeletal muscle contraction. By whole-exome sequencing, we identified the heterozygous RYR1 variant c.14767_14772del resulting in the in-frame deletion p.(Phe4923_Phe4924del) in two brothers with a lethal form of the fetal akinesia deformation syndrome (FADS). The two deleted phenylalanines (RyR1-Δ4923FF4924) are located in the S6 pore-lining helix of RyR1. Clinical features in one of the two siblings included severe hypotonia, thin ribs, swallowing inability, and respiratory insufficiency that caused early death. Functional consequences of the RyR1-Δ4923FF4924 variant were determined using recombinant 2,200-kDa homotetrameric and heterotetrameric RyR1 channel complexes that were expressed in HEK293 cells and characterized by cellular, electrophysiological, and computational methods. Cellular Ca2+ release in response to caffeine indicated that the homotetrameric variant formed caffeine-sensitive Ca2+ conducting channels in HEK293 cells. In contrast, the homotetrameric channel complex was not activated by Ca2+ and did not conduct Ca2+ based on single-channel measurements. The computational analysis suggested decreased protein stability and loss of salt bridge interactions between RyR1-R4944 and RyR1-D4938, increasing the electrostatic interaction energy of Ca2+ in a region 20 Å from the mutant site. Co-expression of wild-type and mutant RyR1s resulted in Ca2+-dependent channel activities that displayed intermediate Ca2+ conductances and suggested maintenance of a reduced Ca2+ release in the two patients. Our findings reveal that the RYR1 pore variant p.(Phe4923_Phe4924del) attenuates the flow of Ca2+ through heterotetrameric channels, but alone was not sufficient to cause FADS, indicating additional genetic factors to be involved.
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Affiliation(s)
- Le Xu
- Department of Biochemistry and Biophysics, University of North Carolina, Chapel Hill, NC 27599-7260, United States
| | - Frederike L Harms
- Institute of Human Genetics, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany
| | - Venkat R Chirasani
- Departments of Pharmacology, and Biochemistry & Molecular Biology, Penn State College of Medicine, Hershey, PA 17033-0850, United States
| | - Daniel A Pasek
- Department of Biochemistry and Biophysics, University of North Carolina, Chapel Hill, NC 27599-7260, United States
| | - Fanny Kortüm
- Institute of Human Genetics, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany
| | - Peter Meinecke
- Institute of Human Genetics, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany
| | - Nikolay V Dokholyan
- Departments of Pharmacology, and Biochemistry & Molecular Biology, Penn State College of Medicine, Hershey, PA 17033-0850, United States
| | - Kerstin Kutsche
- Institute of Human Genetics, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany.
| | - Gerhard Meissner
- Department of Biochemistry and Biophysics, University of North Carolina, Chapel Hill, NC 27599-7260, United States.
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Fusto A, Moyle LA, Gilbert PM, Pegoraro E. Cored in the act: the use of models to understand core myopathies. Dis Model Mech 2019; 12:dmm041368. [PMID: 31874912 PMCID: PMC6955215 DOI: 10.1242/dmm.041368] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
The core myopathies are a group of congenital myopathies with variable clinical expression - ranging from early-onset skeletal-muscle weakness to later-onset disease of variable severity - that are identified by characteristic 'core-like' lesions in myofibers and the presence of hypothonia and slowly or rather non-progressive muscle weakness. The genetic causes are diverse; central core disease is most often caused by mutations in ryanodine receptor 1 (RYR1), whereas multi-minicore disease is linked to pathogenic variants of several genes, including selenoprotein N (SELENON), RYR1 and titin (TTN). Understanding the mechanisms that drive core development and muscle weakness remains challenging due to the diversity of the excitation-contraction coupling (ECC) proteins involved and the differential effects of mutations across proteins. Because of this, the use of representative models expressing a mature ECC apparatus is crucial. Animal models have facilitated the identification of disease progression mechanisms for some mutations and have provided evidence to help explain genotype-phenotype correlations. However, many unanswered questions remain about the common and divergent pathological mechanisms that drive disease progression, and these mechanisms need to be understood in order to identify therapeutic targets. Several new transgenic animals have been described recently, expanding the spectrum of core myopathy models, including mice with patient-specific mutations. Furthermore, recent developments in 3D tissue engineering are expected to enable the study of core myopathy disease progression and the effects of potential therapeutic interventions in the context of human cells. In this Review, we summarize the current landscape of core myopathy models, and assess the hurdles and opportunities of future modeling strategies.
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Affiliation(s)
- Aurora Fusto
- Department of Neuroscience, University of Padua, Padua 35128, Italy
| | - Louise A Moyle
- Donnelly Centre, University of Toronto, Toronto, ON M5S3E1, Canada
- Institute of Biomaterials and Biochemical Engineering, University of Toronto, Toronto, ON M5S3G9, Canada
| | - Penney M Gilbert
- Donnelly Centre, University of Toronto, Toronto, ON M5S3E1, Canada
- Institute of Biomaterials and Biochemical Engineering, University of Toronto, Toronto, ON M5S3G9, Canada
- Department of Cell and Systems Biology, University of Toronto, Toronto, ON M5S3G5, Canada
- Department of Biochemistry, University of Toronto, Toronto, ON M5S1A8, Canada
| | - Elena Pegoraro
- Department of Neuroscience, University of Padua, Padua 35128, Italy
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14
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Nolte W, Weikard R, Brunner RM, Albrecht E, Hammon HM, Reverter A, Kühn C. Biological Network Approach for the Identification of Regulatory Long Non-Coding RNAs Associated With Metabolic Efficiency in Cattle. Front Genet 2019; 10:1130. [PMID: 31824560 PMCID: PMC6883949 DOI: 10.3389/fgene.2019.01130] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2019] [Accepted: 10/17/2019] [Indexed: 12/17/2022] Open
Abstract
Background: Genomic regions associated with divergent livestock feed efficiency have been found predominantly outside protein coding sequences. Long non-coding RNAs (lncRNA) can modulate chromatin accessibility, gene expression and act as important metabolic regulators in mammals. By integrating phenotypic, transcriptomic, and metabolomic data with quantitative trait locus data in prioritizing co-expression network analyses, we aimed to identify and functionally characterize lncRNAs with a potential key regulatory role in metabolic efficiency in cattle. Materials and Methods: Crossbred animals (n = 48) of a Charolais x Holstein F2-population were allocated to groups of high or low metabolic efficiency based on residual feed intake in bulls, energy corrected milk in cows and intramuscular fat content in both genders. Tissue samples from jejunum, liver, skeletal muscle and rumen were subjected to global transcriptomic analysis via stranded total RNA sequencing (RNAseq) and blood plasma samples were used for profiling of 640 metabolites. To identify lncRNAs within the indicated tissues, a project-specific transcriptome annotation was established. Subsequently, novel transcripts were categorized for potential lncRNA status, yielding a total of 7,646 predicted lncRNA transcripts belonging to 3,287 loci. A regulatory impact factor approach highlighted 92, 55, 35, and 73 lncRNAs in jejunum, liver, muscle, and rumen, respectively. Their ensuing high regulatory impact factor scores indicated a potential regulatory key function in a gene set comprising loci displaying differential expression, tissue specificity and loci overlapping with quantitative trait locus regions for residual feed intake or milk production. These were subjected to a partial correlation and information theory analysis with the prioritized gene set. Results and Conclusions: Independent, significant and group-specific correlations (|r| > 0.8) were used to build a network for the high and the low metabolic efficiency group resulting in 1,522 and 1,732 nodes, respectively. Eight lncRNAs displayed a particularly high connectivity (>100 nodes). Metabolites and genes from the partial correlation and information theory networks, which each correlated significantly with the respective lncRNA, were included in an enrichment analysis indicating distinct affected pathways for the eight lncRNAs. LncRNAs associated with metabolic efficiency were classified to be functionally involved in hepatic amino acid metabolism and protein synthesis and in calcium signaling and neuronal nitric oxide synthase signaling in skeletal muscle cells.
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Affiliation(s)
- Wietje Nolte
- Institute of Genome Biology, Leibniz Institute for Farm Animal Biology (FBN), Dummerstorf, Germany
| | - Rosemarie Weikard
- Institute of Genome Biology, Leibniz Institute for Farm Animal Biology (FBN), Dummerstorf, Germany
| | - Ronald M Brunner
- Institute of Genome Biology, Leibniz Institute for Farm Animal Biology (FBN), Dummerstorf, Germany
| | - Elke Albrecht
- Institute of Muscle Biology and Growth, Leibniz Institute for Farm Animal Biology (FBN), Dummerstorf, Germany
| | - Harald M Hammon
- Institute of Nutritional Physiology "Oskar Kellner," Leibniz Institute for Farm Animal Biology (FBN), Dummerstorf, Germany
| | - Antonio Reverter
- Commonwealth Scientific and Industrial Research Organisation (CSIRO) Agriculture and Food, Queensland Bioscience Precinct, St Lucia, QLD, Australia
| | - Christa Kühn
- Institute of Genome Biology, Leibniz Institute for Farm Animal Biology (FBN), Dummerstorf, Germany.,Faculty of Agricultural and Environmental Sciences, University Rostock, Rostock, Germany
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15
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Michelucci A, Boncompagni S, Pietrangelo L, García-Castañeda M, Takano T, Malik S, Dirksen RT, Protasi F. Transverse tubule remodeling enhances Orai1-dependent Ca 2+ entry in skeletal muscle. eLife 2019; 8:47576. [PMID: 31657717 PMCID: PMC6837846 DOI: 10.7554/elife.47576] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2019] [Accepted: 10/24/2019] [Indexed: 12/18/2022] Open
Abstract
Exercise promotes the formation of intracellular junctions in skeletal muscle between stacks of sarcoplasmic reticulum (SR) cisternae and extensions of transverse-tubules (TT) that increase co-localization of proteins required for store-operated Ca2+ entry (SOCE). Here, we report that SOCE, peak Ca2+ transient amplitude and muscle force production during repetitive stimulation are increased after exercise in parallel with the time course of TT association with SR-stacks. Unexpectedly, exercise also activated constitutive Ca2+ entry coincident with a modest decrease in total releasable Ca2+ store content. Importantly, this decrease in releasable Ca2+ store content observed after exercise was reversed by repetitive high-frequency stimulation, consistent with enhanced SOCE. The functional benefits of exercise on SOCE, constitutive Ca2+ entry and muscle force production were lost in mice with muscle-specific loss of Orai1 function. These results indicate that TT association with SR-stacks enhances Orai1-dependent SOCE to optimize Ca2+ dynamics and muscle contractile function during acute exercise.
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Affiliation(s)
- Antonio Michelucci
- Department of Pharmacology and Physiology, University of Rochester School of Medicine and Dentistry, Rochester, United States.,Center for Research on Ageing and Translational Medicine (CeSI-MeT), University Gabriele d'Annunzio, Chieti, Italy
| | - Simona Boncompagni
- Center for Research on Ageing and Translational Medicine (CeSI-MeT), University Gabriele d'Annunzio, Chieti, Italy.,Department of Neuroscience, Imaging and Clinical Sciences (DNICS), University Gabriele d'Annunzio, Chieti, Italy
| | - Laura Pietrangelo
- Center for Research on Ageing and Translational Medicine (CeSI-MeT), University Gabriele d'Annunzio, Chieti, Italy.,Department of Neuroscience, Imaging and Clinical Sciences (DNICS), University Gabriele d'Annunzio, Chieti, Italy
| | - Maricela García-Castañeda
- Department of Pharmacology and Physiology, University of Rochester School of Medicine and Dentistry, Rochester, United States
| | - Takahiro Takano
- Department of Pharmacology and Physiology, University of Rochester School of Medicine and Dentistry, Rochester, United States
| | - Sundeep Malik
- Department of Pharmacology and Physiology, University of Rochester School of Medicine and Dentistry, Rochester, United States
| | - Robert T Dirksen
- Department of Pharmacology and Physiology, University of Rochester School of Medicine and Dentistry, Rochester, United States
| | - Feliciano Protasi
- Center for Research on Ageing and Translational Medicine (CeSI-MeT), University Gabriele d'Annunzio, Chieti, Italy.,Department of Medicine and Ageing Sciences (DMSI), University Gabriele d'Annunzio, Chieti, Italy
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16
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Chirasani VR, Xu L, Addis HG, Pasek DA, Dokholyan NV, Meissner G, Yamaguchi N. A central core disease mutation in the Ca 2+-binding site of skeletal muscle ryanodine receptor impairs single-channel regulation. Am J Physiol Cell Physiol 2019; 317:C358-C365. [PMID: 31166712 DOI: 10.1152/ajpcell.00052.2019] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Cryoelectron microscopy and mutational analyses have shown that type 1 ryanodine receptor (RyR1) amino acid residues RyR1-E3893, -E3967, and -T5001 are critical for Ca2+-mediated activation of skeletal muscle Ca2+ release channel. De novo missense mutation RyR1-Q3970K in the secondary binding sphere of Ca2+ was reported in association with central core disease (CCD) in a 2-yr-old boy. Here, we characterized recombinant RyR1-Q3970K mutant by cellular Ca2+ release measurements, single-channel recordings, and computational methods. Caffeine-induced Ca2+ release studies indicated that RyR1-Q3970K formed caffeine-sensitive, Ca2+-conducting channel in HEK293 cells. However, in single-channel recordings, RyR1-Q3970K displayed low Ca2+-dependent channel activity and greatly reduced activation by caffeine or ATP. A RyR1-Q3970E mutant corresponds to missense mutation RyR2-Q3925E associated with arrhythmogenic syndrome in cardiac muscle. RyR1-Q3970E also formed caffeine-induced Ca2+ release in HEK293 cells and exhibited low activity in the presence of the activating ligand Ca2+ but, in contrast to RyR1-Q3970K, was activated by ATP and caffeine in single-channel recordings. Computational analyses suggested distinct structural rearrangements in the secondary binding sphere of Ca2+ of the two mutants, whereas the interaction of Ca2+ with directly interacting RyR1 amino acid residues Glu3893, Glu3967, and Thr5001 was only minimally affected. We conclude that RyR1-Q3970 has a critical role in Ca2+-dependent activation of RyR1 and that a missense RyR1-Q3970K mutant may give rise to myopathy in skeletal muscle.
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Affiliation(s)
- Venkat R Chirasani
- Departments of Pharmacology and Biochemistry and Molecular Biology, Penn State College of Medicine, Hershey, Pennsylvania
| | - Le Xu
- Department of Biochemistry and Biophysics, University of North Carolina, Chapel Hill, North Carolina
| | - Hannah G Addis
- Department of Regenerative Medicine and Cell Biology, Medical University of South Carolina, Charleston, South Carolina.,Cardiac Signaling Center of University of South Carolina, Medical University of South Carolina and Clemson University, Charleston, South Carolina
| | - Daniel A Pasek
- Department of Biochemistry and Biophysics, University of North Carolina, Chapel Hill, North Carolina
| | - Nikolay V Dokholyan
- Departments of Pharmacology and Biochemistry and Molecular Biology, Penn State College of Medicine, Hershey, Pennsylvania
| | - Gerhard Meissner
- Department of Biochemistry and Biophysics, University of North Carolina, Chapel Hill, North Carolina
| | - Naohiro Yamaguchi
- Department of Regenerative Medicine and Cell Biology, Medical University of South Carolina, Charleston, South Carolina.,Cardiac Signaling Center of University of South Carolina, Medical University of South Carolina and Clemson University, Charleston, South Carolina
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17
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Komatsu M, Nakada T, Kawagishi H, Kato H, Yamada M. Increase in phospholamban content in mouse skeletal muscle after denervation. J Muscle Res Cell Motil 2019; 39:163-173. [DOI: 10.1007/s10974-019-09504-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2019] [Accepted: 02/20/2019] [Indexed: 10/27/2022]
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18
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Suman M, Sharpe JA, Bentham RB, Kotiadis VN, Menegollo M, Pignataro V, Molgó J, Muntoni F, Duchen MR, Pegoraro E, Szabadkai G. Inositol trisphosphate receptor-mediated Ca2+ signalling stimulates mitochondrial function and gene expression in core myopathy patients. Hum Mol Genet 2019; 27:2367-2382. [PMID: 29701772 PMCID: PMC6005141 DOI: 10.1093/hmg/ddy149] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2017] [Accepted: 04/16/2018] [Indexed: 12/19/2022] Open
Abstract
Core myopathies are a group of childhood muscle disorders caused by mutations of the ryanodine receptor (RyR1), the Ca2+ release channel of the sarcoplasmic reticulum. These mutations have previously been associated with elevated inositol trisphosphate receptor (IP3R) levels in skeletal muscle myotubes derived from patients. However, the functional relevance and the relationship of IP3R mediated Ca2+ signalling with the pathophysiology of the disease is unclear. It has also been suggested that mitochondrial dysfunction underlies the development of central and diffuse multi-mini-cores, devoid of mitochondrial activity, which is a key pathological consequence of RyR1 mutations. Here we used muscle biopsies of central core and multi-minicore disease patients with RyR1 mutations, as well as cellular and in vivo mouse models of the disease to characterize global cellular and mitochondrial Ca2+ signalling, mitochondrial function and gene expression associated with the disease. We show that RyR1 mutations that lead to the depletion of the channel are associated with increased IP3-mediated nuclear and mitochondrial Ca2+ signals and increased mitochondrial activity. Moreover, western blot and microarray analysis indicated enhanced mitochondrial biogenesis at the transcriptional and protein levels and was reflected in increased mitochondrial DNA content. The phenotype was recapitulated by RYR1 silencing in mouse cellular myotube models. Altogether, these data indicate that remodelling of skeletal muscle Ca2+ signalling following loss of functional RyR1 mediates bioenergetic adaptation.
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Affiliation(s)
- Matteo Suman
- Department of Biomedical Sciences, University of Padua, 35131 Padua, Italy.,Neuromuscular Unit, Department of Neuroscience, University of Padova, 35131 Padua, Italy
| | - Jenny A Sharpe
- Department of Cell and Developmental Biology, Consortium for Mitochondrial Research, University College London, London WC1E 6BT, UK
| | - Robert B Bentham
- Department of Cell and Developmental Biology, Consortium for Mitochondrial Research, University College London, London WC1E 6BT, UK.,The Francis Crick Institute, London NW1 1AT, UK
| | - Vassilios N Kotiadis
- Department of Cell and Developmental Biology, Consortium for Mitochondrial Research, University College London, London WC1E 6BT, UK
| | - Michela Menegollo
- Department of Biomedical Sciences, University of Padua, 35131 Padua, Italy
| | - Viviana Pignataro
- Department of Biomedical Sciences, University of Padua, 35131 Padua, Italy
| | - Jordi Molgó
- Commissariat à l'Energie Atomique et aux Énergies Alternatives (CEA), Institut des Sciences du Vivant Frédéric Joliot, Université Paris-Saclay, Service d'Ingénierie Moléculaire des Protéines, Gif-sur-Yvette 91191, France.,Institut des Neurosciences Paris-Saclay, UMR 9197, Centre National de la Recherche Scientifique (CNRS)/Université Paris-Sud, Gif-sur-Yvette 91198, France
| | - Francesco Muntoni
- University College London, Great Ormond Street Institute of Child Health Dubowitz Neuromuscular Centre and Medical Research Council (MRC) Centre for Neuromuscular Diseases, London WC1N 1EH, UK
| | - Michael R Duchen
- Department of Cell and Developmental Biology, Consortium for Mitochondrial Research, University College London, London WC1E 6BT, UK
| | - Elena Pegoraro
- Neuromuscular Unit, Department of Neuroscience, University of Padova, 35131 Padua, Italy
| | - Gyorgy Szabadkai
- Department of Biomedical Sciences, University of Padua, 35131 Padua, Italy.,Department of Cell and Developmental Biology, Consortium for Mitochondrial Research, University College London, London WC1E 6BT, UK.,The Francis Crick Institute, London NW1 1AT, UK
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19
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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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20
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Robinson K, Easton CJ, Dulhunty AF, Casarotto MG. Exploiting Peptidomimetics to Synthesize Compounds That Activate Ryanodine Receptor Calcium Release Channels. ChemMedChem 2018; 13:1957-1971. [DOI: 10.1002/cmdc.201800366] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2018] [Revised: 07/24/2018] [Indexed: 11/11/2022]
Affiliation(s)
- Ken Robinson
- Research School of Chemistry Australian National University Canberra Australia
| | | | - Angela F. Dulhunty
- 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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21
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Genetic Polymorphism in the RYR1 C6487T Is Associated with Severity of Hypospadias in Chinese Han Children. BIOMED RESEARCH INTERNATIONAL 2018; 2018:7397839. [PMID: 30027098 PMCID: PMC6031201 DOI: 10.1155/2018/7397839] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/05/2018] [Accepted: 04/01/2018] [Indexed: 11/28/2022]
Abstract
Objective Hypospadias is a common congenital malformation of the male external genitalia. Most cases have an unknown etiology, which is probably a mix of monogenic and multifactorial forms, implicating both genetic and environmental factors. Ryanodine receptor 1 (RYR1) mutations are a common cause of congenital diseases associated with both dominant and recessive inheritance in humans. Herein, we evaluated the correlations of RYR1 C6487T polymorphism with the risk and severity of hypospadias. Methods 263 congenital hypospadias children and 312 healthy children were recruited. The polymorphism of RYR1 C6487T in the peripheral blood was detected by polymerase chain reaction-restriction fragment length polymorphism, and different genotypes and allelic genes were analyzed to explore their associations with the risk of congenital hypospadias. Results The distribution frequencies of CC/CT/TT genotypes and two alleles (C and T) at RYR1 C6487T showed significant differences between the case and control groups (P < 0.05). The frequency of C allele in the case and control groups was 46.95% and 54.94%, respectively, and of T allele was 53.05% and 45.06% (P < 0.05). In addition, the distribution frequency of CC/CT/TT genotypes exhibited significant difference between patients with mild hypospadias and those with moderate or severe hypospadias (all P > 0.05), suggesting that RYR1 C6487T polymorphism is correlated with the severity of congenital hypospadias (X2 = 13.722, P = 0.001). Conclusion Our study demonstrated that RYR1 C6487T polymorphism might be associated with an increased risk of congenital hypospadias in Chinese Han children. Our findings highlight the heterogeneous nature of hypospadias genetic susceptibility.
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22
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Samões R, Oliveira J, Taipa R, Coelho T, Cardoso M, Gonçalves A, Santos R, Melo Pires M, Santos M. RYR1-Related Myopathies: Clinical, Histopathologic and Genetic Heterogeneity Among 17 Patients from a Portuguese Tertiary Centre. J Neuromuscul Dis 2018; 4:67-76. [PMID: 28269792 DOI: 10.3233/jnd-160199] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
BACKGROUND Pathogenic variants in ryanodine receptor type 1 (RYR1) gene are an important cause of congenital myopathy. The clinical, histopathologic and genetic spectrum is wide. OBJECTIVE Review a group of the patients diagnosed with ryanodinopathy in a tertiary centre from North Portugal, as an attempt to define some phenotypical patterns that may help guiding future diagnosis. METHODS Patients were identified from the database of the reference centre for Neuromuscular Disorders in North Portugal. Their data (clinical, histological and genetic) was retrospectively accessed. RESULTS Seventeen RYR1-related patients (including 4 familial cases) were identified. They were divided in groups according to three distinctive clinical characteristics: extraocular muscle (EOM) weakness (N = 6), disproportionate axial muscle weakness (N = 2) and joint laxity (N = 5). The fourth phenotype includes patients with mild tetraparesis and no distinctive clinical features (N = 4). Four different histopathological patterns were found: centronuclear (N = 5), central core (N = 4), type 1 fibres predominance (N = 4) and congenital fibre type disproportion (N = 1) myopathies. Each index case, except two patients, had a different RYR1 variant. Four new genetic variants were identified. All centronuclear myopathies were associated with autosomal recessive inheritance and EOM weakness. All central core myopathies were caused by pathogenic variants in hotspot 3 with autosomal dominant inheritance. Three genetic variants were reported to be associated to malignant hyperthermia susceptibility. CONCLUSIONS Distinctive clinical features were recognized as diagnostically relevant: extraocular muscle weakness (and centronuclear pattern on muscle biopsy), severe axial weakness disproportionate to the ambulatory state and mild tetraparesis associated with (proximal) joint laxity. There was a striking genetic heterogeneity, including four new RYR1 variants.
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Affiliation(s)
- Raquel Samões
- Department of Neurology, Centro Hospitalar do Porto, Porto, Portugal
| | - Jorge Oliveira
- Unidade de Genética Molecular, Centro de Genética Médica, Centro Hospitalar do Porto, Porto, Portugal.,Unidade Multidisciplinar de Investigação Biomédica (UMIB), Instituto de Ciências Biomédicas Abel Salazar (ICBAS), Universidade do Porto, Porto, Portugal
| | - Ricardo Taipa
- Neuropathology Unit, Centro Hospitalar do Porto, Porto, Portugal
| | - Teresa Coelho
- Department of Neurophysiology and Neuromuscular Disorders Outpatient Clinic, Centro Hospitalar do Porto, Porto, Portugal
| | - Márcio Cardoso
- Department of Neurophysiology and Neuromuscular Disorders Outpatient Clinic, Centro Hospitalar do Porto, Porto, Portugal
| | - Ana Gonçalves
- Unidade de Genética Molecular, Centro de Genética Médica, Centro Hospitalar do Porto, Porto, Portugal.,Unidade Multidisciplinar de Investigação Biomédica (UMIB), Instituto de Ciências Biomédicas Abel Salazar (ICBAS), Universidade do Porto, Porto, Portugal
| | - Rosário Santos
- Unidade de Genética Molecular, Centro de Genética Médica, Centro Hospitalar do Porto, Porto, Portugal.,Unidade Multidisciplinar de Investigação Biomédica (UMIB), Instituto de Ciências Biomédicas Abel Salazar (ICBAS), Universidade do Porto, Porto, Portugal.,UCIBIO/REQUIMTE, Departamento de Ciências Biológicas, Laboratório de Bioquímica, Faculdade de Farmácia, Universidade do Porto, Porto, Portugal
| | | | - Manuela Santos
- Neuromuscular Disorders Outpatient Clinic and Department of Neuropaediatrics, Centro Hospitalar do Porto, Porto, Portugal
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Abstract
During the complex series of events leading to muscle contraction, the initial electric signal coming from motor neurons is transformed into an increase in calcium concentration that triggers sliding of myofibrils. This process, referred to as excitation-contraction coupling, is reliant upon the calcium-release complex, which is restricted spatially to a sub-compartment of muscle cells ("the triad") and regulated precisely. Any dysfunction in the calcium-release complex leads to muscle impairment and myopathy. Various causes can lead to alterations in excitation-contraction coupling and to muscle diseases. The latter are reviewed and classified into four categories: (i) mutation in a protein of the calcium-release complex; (ii) alteration in triad structure; (iii) modification of regulation of channels; (iv) modification in calcium stores within the muscle. Current knowledge of the pathophysiologic mechanisms in each category is described and discussed.
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Affiliation(s)
- Isabelle Marty
- University Grenoble Alpes, Grenoble Institut des Neurosciences, GIN, F-38000 Grenoble, France.,INSERM, U1216, F-38000 Grenoble, France
| | - Julien Fauré
- University Grenoble Alpes, Grenoble Institut des Neurosciences, GIN, F-38000 Grenoble, France.,INSERM, U1216, F-38000 Grenoble, France.,CHU de Grenoble, F-38000 Grenoble, France
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24
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Disturbed Ca 2+ Homeostasis in Muscle-Wasting Disorders. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2018; 1088:307-326. [PMID: 30390258 DOI: 10.1007/978-981-13-1435-3_14] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Ca2+ is essential for proper structure and function of skeletal muscle. It not only activates contraction and force development but also participates in multiple signaling pathways. Low levels of Ca2+ restrain muscle regeneration by limiting the fusion of satellite cells. Ironically, sustained elevations of Ca2+ also result in muscle degeneration as this ion promotes high rates of protein breakdown. Moreover, transforming growth factors (TGFs) which are well known for controlling muscle growth also regulate Ca2+ channels. Thus, therapies focused on changing levels of Ca2+ and TGFs are promising for treating muscle-wasting disorders. Three principal systems govern the homeostasis of Ca2+, namely, excitation-contraction (EC) coupling, excitation-coupled Ca2+ entry (ECCE), and store-operated Ca2+ entry (SOCE). Accordingly, alterations in these systems can lead to weakness and atrophy in many hereditary diseases, such as Brody disease, central core disease (CCD), tubular aggregate myopathy (TAM), myotonic dystrophy type 1 (MD1), oculopharyngeal muscular dystrophy (OPMD), and Duchenne muscular dystrophy (DMD). Here, the interrelationship between all these molecules and processes is reviewed.
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25
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A chemical chaperone improves muscle function in mice with a RyR1 mutation. Nat Commun 2017; 8:14659. [PMID: 28337975 PMCID: PMC5376670 DOI: 10.1038/ncomms14659] [Citation(s) in RCA: 50] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2016] [Accepted: 01/20/2017] [Indexed: 12/28/2022] Open
Abstract
Mutations in the RYR1 gene cause severe myopathies. Mice with an I4895T mutation in the type 1 ryanodine receptor/Ca2+ release channel (RyR1) display muscle weakness and atrophy, but the underlying mechanisms are unclear. Here we show that the I4895T mutation in RyR1 decreases the amplitude of the sarcoplasmic reticulum (SR) Ca2+ transient, resting cytosolic Ca2+ levels, muscle triadin content and calsequestrin (CSQ) localization to the junctional SR, and increases endoplasmic reticulum (ER) stress/unfolded protein response (UPR) and mitochondrial ROS production. Treatment of mice carrying the I4895T mutation with a chemical chaperone, sodium 4-phenylbutyrate (4PBA), reduces ER stress/UPR and improves muscle function, but does not restore SR Ca2+ transients in I4895T fibres to wild type levels, suggesting that decreased SR Ca2+ release is not the major driver of the myopathy. These findings suggest that 4PBA, an FDA-approved drug, has potential as a therapeutic intervention for RyR1 myopathies that are associated with ER stress. Mutations in the RyR1 channel cause core myopathies. Here the authors show that ER stress and the unfolded protein response underlie the pathology caused by a common RyR1 channel mutation, and show that treatment with a chemical chaperone restores muscle function in mice.
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Jungbluth H, Dowling JJ, Ferreiro A, Muntoni F, Bönnemann C, Dirksen R, Faure J, Hamilton S, Hopkins P, Marks A, Marty I, Meilleur K, Riazi S, Sewry C, Treves S, Voermans N, Zorzato F. 217th ENMC International Workshop: RYR1-related myopathies, Naarden, The Netherlands, 29–31 January 2016. Neuromuscul Disord 2016; 26:624-33. [DOI: 10.1016/j.nmd.2016.06.001] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2016] [Accepted: 06/02/2016] [Indexed: 12/22/2022]
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Moulin M, Ferreiro A. Muscle redox disturbances and oxidative stress as pathomechanisms and therapeutic targets in early-onset myopathies. Semin Cell Dev Biol 2016; 64:213-223. [PMID: 27531051 DOI: 10.1016/j.semcdb.2016.08.003] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2016] [Accepted: 08/08/2016] [Indexed: 01/07/2023]
Abstract
Because of their contractile activity and their high oxygen consumption and metabolic rate, skeletal muscles continually produce moderate levels of reactive oxygen and nitrogen species (ROS/RNS), which increase during exercise and are buffered by multiple antioxidant systems to maintain redox homeostasis. Imbalance between ROS/RNS production and elimination results in oxidative stress (OxS), which has been implicated in ageing and in numerous human diseases, including cancer, diabetes or age-related muscle loss (sarcopenia). The study of redox homeostasis in muscle was hindered by its lability, by the many factors influencing technical OxS measures and by ROS/RNS important roles in signaling pathways and adaptative responses to muscle contraction and effort, which make it difficult to define a threshold between physiological signaling and pathological conditions. In the last years, new tools have been developed that facilitate the study of these key mechanisms, and deregulation of redox homeostasis has emerged as a key pathogenic mechanism and potential therapeutic target in muscle conditions. This is in particular the case for early-onset myopathies, genetic muscle diseases which present from birth or early childhood with muscle weakness interfering with ambulation and often with cardiac or respiratory failure leading to premature death. Inherited defects of the reductase selenoprotein N in SEPN1-related myopathy leads to chronic OxS of monogenic origin as a primary disease pathomechanism. In myopathies associated with mutations of the genes encoding the calcium channel RyR1, the extracellular matrix protein collagen VI or the sarcolemmal protein dystrophin (Duchenne Muscular Dystrophy), OxS has been identified as a relevant secondary pathophysiological mechanism. OxS being drug-targetable, it represents an interesting therapeutic target for these incurable conditions, and following preclinical correction of the cell or animal model phenotype, the first clinical trials with the antioxidants N-acetylcysteine (SEPN1- and RYR1-related myopathies) or epigallocatechin-gallate (DMD) have been launched recently. In this review, we provide an overview of the mechanisms involved in redox regulation in skeletal muscle, the technical tools available to measure redox homeostasis in muscle cells, the bases of OxS as a primary or secondary pathomechanism in early-onset myopathies and the innovative clinical trials with antioxidants which are currently in progress for these so-far untreatable infantile muscle diseases. Progress in our knowledge of redox homeostasis defects in these rare muscle conditions may be useful as a model paradigm to understand and treat other conditions in which OxS is involved, including prevalent conditions with major socioeconomic impact such as insulin resistance, cachexia, obesity, sarcopenia or ageing.
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Affiliation(s)
- Maryline Moulin
- Pathophysiology of Striated Muscles Laboratory, Unit of Functional and Adaptive Biology (BFA), University Paris Diderot, Sorbonne Paris Cité, BFA, UMR CNRS 8251, 75250, Paris Cedex 13, France.
| | - Ana Ferreiro
- Pathophysiology of Striated Muscles Laboratory, Unit of Functional and Adaptive Biology (BFA), University Paris Diderot, Sorbonne Paris Cité, BFA, UMR CNRS 8251, 75250, Paris Cedex 13, France; AP-HP, Centre de Référence Maladies Neuromusculaires Paris-Est, Groupe Hospitalier Pitié-Salpêtrière, 75013, Paris, France.
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Ríos E, Figueroa L, Manno C, Kraeva N, Riazi S. The couplonopathies: A comparative approach to a class of diseases of skeletal and cardiac muscle. ACTA ACUST UNITED AC 2016; 145:459-74. [PMID: 26009541 PMCID: PMC4442791 DOI: 10.1085/jgp.201411321] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
A novel category of diseases of striated muscle is proposed, the couplonopathies, as those that affect components of the couplon and thereby alter its operation. Couplons are the functional units of intracellular calcium release in excitation–contraction coupling. They comprise dihydropyridine receptors, ryanodine receptors (Ca2+ release channels), and a growing list of ancillary proteins whose alteration may lead to disease. Within a generally similar plan, the couplons of skeletal and cardiac muscle show, in a few places, marked structural divergence associated with critical differences in the mechanisms whereby they fulfill their signaling role. Most important among these are the presence of a mechanical or allosteric communication between voltage sensors and Ca2+ release channels, exclusive to the skeletal couplon, and the smaller capacity of the Ca stores in cardiac muscle, which results in greater swings of store concentration during physiological function. Consideration of these structural and functional differences affords insights into the pathogenesis of several couplonopathies. The exclusive mechanical connection of the skeletal couplon explains differences in pathogenesis between malignant hyperthermia (MH) and catecholaminergic polymorphic ventricular tachycardia (CPVT), conditions most commonly caused by mutations in homologous regions of the skeletal and cardiac Ca2+ release channels. Based on mechanistic considerations applicable to both couplons, we identify the plasmalemma as a site of secondary modifications, typically an increase in store-operated calcium entry, that are relevant in MH pathogenesis. Similar considerations help explain the different consequences that mutations in triadin and calsequestrin have in these two tissues. As more information is gathered on the composition of cardiac and skeletal couplons, this comparative and mechanistic approach to couplonopathies should be useful to understand pathogenesis, clarify diagnosis, and propose tissue-specific drug development.
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Affiliation(s)
- Eduardo Ríos
- Section of Cellular Signaling, Department of Molecular Biophysics and Physiology, Rush University, Chicago, IL 60612
| | - Lourdes Figueroa
- Section of Cellular Signaling, Department of Molecular Biophysics and Physiology, Rush University, Chicago, IL 60612
| | - Carlo Manno
- Section of Cellular Signaling, Department of Molecular Biophysics and Physiology, Rush University, Chicago, IL 60612
| | - Natalia Kraeva
- Malignant Hyperthermia Investigation Unit, University Health Network, Toronto General Hospital, Toronto, Ontario M5G 2C4, Canada
| | - Sheila Riazi
- Malignant Hyperthermia Investigation Unit, University Health Network, Toronto General Hospital, Toronto, Ontario M5G 2C4, Canada
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Hernández-Ochoa EO, Pratt SJP, Lovering RM, Schneider MF. Critical Role of Intracellular RyR1 Calcium Release Channels in Skeletal Muscle Function and Disease. Front Physiol 2016; 6:420. [PMID: 26793121 PMCID: PMC4709859 DOI: 10.3389/fphys.2015.00420] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2015] [Accepted: 12/21/2015] [Indexed: 01/25/2023] Open
Abstract
The skeletal muscle Ca2+ release channel, also known as ryanodine receptor type 1 (RyR1), is the largest ion channel protein known and is crucial for effective skeletal muscle contractile activation. RyR1 function is controlled by Cav1.1, a voltage gated Ca2+ channel that works mainly as a voltage sensor for RyR1 activity during skeletal muscle contraction and is also fine-tuned by Ca2+, several intracellular compounds (e.g., ATP), and modulatory proteins (e.g., calmodulin). Dominant and recessive mutations in RyR1, as well as acquired channel alterations, are the underlying cause of various skeletal muscle diseases. The aim of this mini review is to summarize several current aspects of RyR1 function, structure, regulation, and to describe the most common diseases caused by hereditary or acquired RyR1 malfunction.
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Affiliation(s)
- Erick O Hernández-Ochoa
- Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine Baltimore, MD, USA
| | - Stephen J P Pratt
- Department of Orthopaedics, University of Maryland School of Medicine Baltimore, MD, USA
| | - Richard M Lovering
- Department of Orthopaedics, University of Maryland School of Medicine Baltimore, MD, USA
| | - Martin F Schneider
- Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine Baltimore, MD, USA
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30
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Cacheux M, Blum A, Sébastien M, Wozny AS, Brocard J, Mamchaoui K, Mouly V, Roux-Buisson N, Rendu J, Monnier N, Krivosic R, Allen P, Lacour A, Lunardi J, Fauré J, Marty I. Functional Characterization of a Central Core Disease RyR1 Mutation (p.Y4864H) Associated with Quantitative Defect in RyR1 Protein. J Neuromuscul Dis 2015; 2:421-432. [PMID: 27858745 PMCID: PMC5240544 DOI: 10.3233/jnd-150073] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Background: Central Core Disease (CCD) is a congenital myopathy often resulting from a mutation in RYR1 gene. Mutations in RyR1 can increase or decrease channel activity, or induce a reduction in the amount of protein. The consequences of a single mutation are sometimes multiple and the analysis of the functional effects is complex. Objective: The consequences of the p.Y4864H mutation identified in a CCD patient have been studied regarding both RyR1 function and amount. Methods: The amount of RyR1 in human and mouse muscles was evaluated using qRT-PCR and quantitative Western blot, and calcium release was studied using calcium imaging on primary cultures. The results were compared between human and mouse. Results: The p.Y4864H mutation induced an alteration of calcium release, and in addition was associated to a reduction in the amount of RyR1 in the patient’s muscle. This suggests two possible pathophysiological mechanisms: the alteration of calcium release could result from a modification of the channel properties of RyR1 or from a RyR1 reduction. In order to discriminate between the two hypotheses, we used the heterozygous RyR1 knockout (RyR1+/–) mouse model showing a comparable RyR1 protein reduction. No reduction in calcium release was observed in primary muscle culture from these mice, and no muscle weakness was measured. Conclusions: Because the reduction in the amount of RyR1 protein has no functional consequences in the murine model, the muscle weakness observed in the patient is most likely the result of a modification of the calcium channel function of RyR1 due to the p.Y4864H mutation.
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Affiliation(s)
- Marine Cacheux
- INSERM U836, Grenoble Institut des Neurosciences, Equipe Muscle et Pathologies, Grenoble, France.,Université Joseph Fourier, Grenoble, France
| | - Ariane Blum
- INSERM U836, Grenoble Institut des Neurosciences, Equipe Muscle et Pathologies, Grenoble, France.,Université Joseph Fourier, Grenoble, France
| | - Muriel Sébastien
- INSERM U836, Grenoble Institut des Neurosciences, Equipe Muscle et Pathologies, Grenoble, France.,Université Joseph Fourier, Grenoble, France
| | - Anne Sophie Wozny
- INSERM U836, Grenoble Institut des Neurosciences, Equipe Muscle et Pathologies, Grenoble, France.,Université Joseph Fourier, Grenoble, France.,Centre Hospitalier Régional Universitaire de Grenoble, Hôpital Michallon, Biochimie Génétique et Moléculaire, Grenoble, France
| | - Julie Brocard
- INSERM U836, Grenoble Institut des Neurosciences, Equipe Muscle et Pathologies, Grenoble, France.,Université Joseph Fourier, Grenoble, France
| | - Kamel Mamchaoui
- UMRS974 Inserm, UMR7215 CNRS, Institut de Myologie, GH PitiéSalpétrière, 47 bd de l'hôpital, Paris, France
| | - Vincent Mouly
- UMRS974 Inserm, UMR7215 CNRS, Institut de Myologie, GH PitiéSalpétrière, 47 bd de l'hôpital, Paris, France
| | - Nathalie Roux-Buisson
- INSERM U836, Grenoble Institut des Neurosciences, Equipe Muscle et Pathologies, Grenoble, France.,Université Joseph Fourier, Grenoble, France.,Centre Hospitalier Régional Universitaire de Grenoble, Hôpital Michallon, Biochimie Génétique et Moléculaire, Grenoble, France
| | - John Rendu
- INSERM U836, Grenoble Institut des Neurosciences, Equipe Muscle et Pathologies, Grenoble, France.,Université Joseph Fourier, Grenoble, France.,Centre Hospitalier Régional Universitaire de Grenoble, Hôpital Michallon, Biochimie Génétique et Moléculaire, Grenoble, France
| | - Nicole Monnier
- INSERM U836, Grenoble Institut des Neurosciences, Equipe Muscle et Pathologies, Grenoble, France.,Université Joseph Fourier, Grenoble, France.,Centre Hospitalier Régional Universitaire de Grenoble, Hôpital Michallon, Biochimie Génétique et Moléculaire, Grenoble, France
| | - Renée Krivosic
- Département Anesthésie-Réanimation, Hôpital Roger Salengro, CHRU de Lille, Lille, France
| | - Paul Allen
- Department of Molecular Biosciences, School of Veterinary Medicine, University of California at Davis, Davis CA, USA
| | - Arnaud Lacour
- Service de Neurologie, Hôpital Roger Salengro, CHRU de Lille, Lille, France
| | - Joël Lunardi
- INSERM U836, Grenoble Institut des Neurosciences, Equipe Muscle et Pathologies, Grenoble, France.,Université Joseph Fourier, Grenoble, France.,Centre Hospitalier Régional Universitaire de Grenoble, Hôpital Michallon, Biochimie Génétique et Moléculaire, Grenoble, France
| | - Julien Fauré
- INSERM U836, Grenoble Institut des Neurosciences, Equipe Muscle et Pathologies, Grenoble, France.,Université Joseph Fourier, Grenoble, France.,Centre Hospitalier Régional Universitaire de Grenoble, Hôpital Michallon, Biochimie Génétique et Moléculaire, Grenoble, France
| | - Isabelle Marty
- INSERM U836, Grenoble Institut des Neurosciences, Equipe Muscle et Pathologies, Grenoble, France.,Université Joseph Fourier, Grenoble, France
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31
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Alaverdashvili M, Li X, Paterson PG. Protein-Energy Malnutrition Causes Deficits in Motor Function in Adult Male Rats. J Nutr 2015; 145:2503-11. [PMID: 26423735 PMCID: PMC5469620 DOI: 10.3945/jn.115.216382] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2015] [Accepted: 09/03/2015] [Indexed: 01/10/2023] Open
Abstract
BACKGROUND Adult protein-energy malnutrition (PEM) often occurs in combination with neurological disorders affecting hand use and walking ability. The independent effects of PEM on motor function are not well characterized and may be obscured by these comorbidities. OBJECTIVE Our goal was to undertake a comprehensive evaluation of sensorimotor function with the onset and progression of PEM in an adult male rat model. METHODS In Expt. 1 and Expt. 2, male Sprague-Dawley rats (14-15 wk old) were assigned ad libitum access for 4 wk to normal-protein (NP) or low-protein (LP) diets containing 12.5% and 0.5% protein, respectively. Expt. 1 assessed muscle strength, balance, and skilled walking ability on days 2, 8, and 27 by bar-holding, cylinder, and horizontal ladder walking tasks, respectively. In addition to food intake and body weight, nutritional status was determined on days 3, 9, and 28 by serum acute-phase reactant and corticosterone concentrations and liver lipids. Expt. 2 addressed the effect of an LP diet on hindlimb muscle size. RESULTS PEM evolved over time in rats consuming the LP diet. Total food intake decreased by 24% compared with the NP group. On day 28, body weight and serum albumin decreased by 31% and 26%, respectively, and serum α2-macroglobulin increased by 445% (P < 0.05) in the LP group compared with the NP group. Forelimb dysfunction (173% increase in adaptive flexed-arm-hang score) developed on day 2 in rats fed the LP diet (P < 0.001), whereas abnormal walking (34% decreased incidence of correct hindlimb placement) developed by day 27 (P < 0.05). Relative to the NP diet, the LP diet reduced the cross-sectional area of gastrocnemius medialis (P < 0.05). CONCLUSIONS PEM in adult male rats causes a variety of sensorimotor abnormalities that develop at different stages of malnutrition. This model can be used in combination with disease models of sensorimotor deficits to examine the interactions between nutritional status, other treatments, and disease progression.
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Affiliation(s)
- Mariam Alaverdashvili
- Neuroscience Research Group and College of Pharmacy and Nutrition, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
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32
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Kivlan BR, Carcia CR, Clemente FR, Phelps AL, Martin RL. The effect of Astym® Therapy on muscle strength: a blinded, randomized, clinically controlled trial. BMC Musculoskelet Disord 2015; 16:325. [PMID: 26510526 PMCID: PMC4625642 DOI: 10.1186/s12891-015-0778-9] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/08/2015] [Accepted: 10/15/2015] [Indexed: 11/24/2022] Open
Abstract
Background Astym® therapy is a manual therapy intervention used to stimulate tissue healing, decrease pain, improve mobility, and improve muscle performance associated with musculoskeletal pathology. The purpose of this study was to determine if Astym therapy administered to the lower extremity would result in an immediate change of maximal force output during a unilateral isometric squat test among individuals with a lower extremity injury. Methods Forty-five subjects (14 males; 31females) between 18 and 65 years of age were randomized into 3 treatment groups: 1) Control group – received no treatment 2) Placebo group – received a sham Astym treatment 3) Astym therapy group– received Astym therapy to the lower extremity. A baseline measure of maximal force output (pre-test) during a unilateral isometric squat was performed. The subjects then received the designated treatment intervention. Immediately following the treatment intervention, maximal force output (post-test) was retested using identical testing procedures by an investigator who was blinded to the treatment intervention received by the subjects. The percent change of maximal force output from pre-test to post-test measures was compared using a one-way analysis of variance. A Tukey’s post-hoc analysis determined the statistical differences between the groups. Results The treatment intervention had a significant effect on the percent change of maximal force output [F(2,42) = 7.91, p = 0.001]. Tukey’s post hoc analysis demonstrated that the percent change of maximal force output was significantly greater in the Astym group (15 ± 18 % change of Newtons) compared to the placebo (−6 ± 11 % change of Newtons; p = 0.0001) and control (−1 ± 17 % change of Newtons; p = 0.0014) groups. No significant difference (p = 0.68) was noted between the control and placebo groups. Conclusions Astym therapy to the involved lower extremity increased maximum force output during an isometric squat test immediately following treatment. The results of this study suggest that Astym therapy can immediately improve muscle performance (maximal force output) for patients presenting with muscular weakness caused by a lower extremity musculoskeletal injury. Trial registration Clinicaltrials.gov NCT02349230. Registered 23 January 2015.
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Affiliation(s)
- Benjamin R Kivlan
- Department of Physical Therapy, John G. Rangos Sr.,School of Health Sciences, Duquesne University, Pittsburgh, PA, 15282, USA. .,Tri-State Physical Therapy, Pittsburgh, PA, USA.
| | - Christopher R Carcia
- Department of Physical Therapy, John G. Rangos Sr.,School of Health Sciences, Duquesne University, Pittsburgh, PA, 15282, USA.
| | - F Richard Clemente
- Department of Physical Therapy, John G. Rangos Sr.,School of Health Sciences, Duquesne University, Pittsburgh, PA, 15282, USA.
| | - Amy L Phelps
- Palumbo Donahue School of Business, Duquesne University, Pittsburgh, PA, USA.
| | - RobRoy L Martin
- Department of Physical Therapy, John G. Rangos Sr.,School of Health Sciences, Duquesne University, Pittsburgh, PA, 15282, USA. .,UPMC Center for Sports Medicine, Pittsburgh, PA, USA.
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Zvaritch E, MacLennan DH. Muscle spindles exhibit core lesions and extensive degeneration of intrafusal fibers in the Ryr1(I4895T/wt) mouse model of core myopathy. Biochem Biophys Res Commun 2015; 460:34-9. [PMID: 25619131 DOI: 10.1016/j.bbrc.2015.01.056] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2015] [Accepted: 01/13/2015] [Indexed: 11/15/2022]
Abstract
Muscle spindles from the hind limb muscles of adult Ryr1(I4895T/wt) (IT/+) mice exhibit severe structural abnormalities. Up to 85% of the spindles are separated from skeletal muscle fascicles by a thick layer of connective tissue. Many intrafusal fibers exhibit degeneration, with Z-line streaming, compaction and collapse of myofibrillar bundles, mitochondrial clumping, nuclear shrinkage and pyknosis. The lesions resemble cores observed in the extrafusal myofibers of this animal model and of core myopathy patients. Spindle abnormalities precede those in extrafusal fibers, indicating that they are a primary pathological feature in this murine Ryr1-related core myopathy. Muscle spindle involvement, if confirmed for human core myopathy patients, would provide an explanation for an array of devastating clinical features characteristic of these diseases and provide novel insights into the pathology of RYR1-related myopathies.
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Affiliation(s)
- Elena Zvaritch
- Banting and Best Department of Medical Research, University of Toronto, Charles H. Best Institute, 112 College Street, Toronto, ON M5G 1L6, Canada
| | - David H MacLennan
- Banting and Best Department of Medical Research, University of Toronto, Charles H. Best Institute, 112 College Street, Toronto, ON M5G 1L6, Canada.
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Hanson MG, Wilde JJ, Moreno RL, Minic AD, Niswander L. Potassium dependent rescue of a myopathy with core-like structures in mouse. eLife 2015; 4. [PMID: 25564733 PMCID: PMC4309926 DOI: 10.7554/elife.02923] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2014] [Accepted: 01/07/2015] [Indexed: 01/24/2023] Open
Abstract
Myopathies decrease muscle functionality. Mutations in ryanodine receptor 1 (RyR1) are often associated with myopathies with microscopic core-like structures in the muscle fiber. In this study, we identify a mouse RyR1 model in which heterozygous animals display clinical and pathological hallmarks of myopathy with core-like structures. The RyR1 mutation decreases sensitivity to activated calcium release and myoplasmic calcium levels, subsequently affecting mitochondrial calcium and ATP production. Mutant muscle shows a persistent potassium leak and disrupted expression of regulators of potassium homeostasis. Inhibition of KATP channels or increasing interstitial potassium by diet or FDA-approved drugs can reverse the muscle weakness, fatigue-like physiology and pathology. We identify regulators of potassium homeostasis as biomarkers of disease that may reveal therapeutic targets in human patients with myopathy of central core disease (CCD). Altogether, our results suggest that amelioration of potassium leaks through potassium homeostasis mechanisms may minimize muscle damage of myopathies due to certain RyR1 mutations.
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Affiliation(s)
- M Gartz Hanson
- Department of Pediatrics, University of Colorado, Anschutz Medical Campus, Aurora, United States
| | - Jonathan J Wilde
- Department of Pediatrics, University of Colorado, Anschutz Medical Campus, Aurora, United States
| | - Rosa L Moreno
- Department of Physiology, University of Colorado, Anschutz Medical Campus, Aurora, United States
| | - Angela D Minic
- Department of Pediatrics, University of Colorado, Anschutz Medical Campus, Aurora, United States
| | - Lee Niswander
- Department of Pediatrics, University of Colorado, Anschutz Medical Campus, Aurora, United States
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The disorders of the calcium release unit of skeletal muscles: what have we learned from mouse models? J Muscle Res Cell Motil 2014; 36:61-9. [PMID: 25424378 DOI: 10.1007/s10974-014-9396-7] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2014] [Accepted: 10/29/2014] [Indexed: 01/01/2023]
Abstract
Calcium storage, release, and reuptake are essential for normal physiological function of muscle. Several human skeletal muscle disorders can arise from dysfunction in the control and coordination of these three critical processes. The release from the Sarcoplasmic Reticulum stores (SR) is handled by a multiprotein complex called Calcium Release Unit and composed of DiHydroPyridine Receptor or DHPR, Ryanodine Receptor or RYR, Calsequestrin or CASQ, junctin, Triadin, Junctophilin and Mitsugumin 29. Malignant hyperthermia (MH), Central Core Disease (CCD), Exertional/environmental Heat Stroke (EHS) and Multiminicore disease (MmD) are inherited disorders of calcium homeostasis in skeletal muscles directly related to mutations of genes coding for proteins of the CRU, primarily ryanodine receptor (RYR1). To understand the pathophysiology of MH and CCD, four murine lines carrying point mutations of human RYR1 have been developed: Y524S, R163C, I4898T and T4826I. Mice carrying those mutations show a phenotype with the traits of MH and/or CCD. Interestingly, also ablation of skeletal muscle calsequestrin (CASQ1) leads to a phenotype with MH-like lethal episodes in response to halothane and heat stress and development of central cores. In this review, we aim to describe the murine lines with RYR mutations or CASQ ablation, which show a phenotype similar to human MH or CCD, to underline their specific phenotypes and their differences and to discuss their contribution to the understanding of the pathophysiology of the disorders and the development of therapeutic strategies.
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36
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Role of Mitofusin-2 in mitochondrial localization and calcium uptake in skeletal muscle. Cell Calcium 2014; 57:14-24. [PMID: 25477138 DOI: 10.1016/j.ceca.2014.11.002] [Citation(s) in RCA: 77] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2014] [Accepted: 11/04/2014] [Indexed: 12/21/2022]
Abstract
As muscle contraction requires ATP and Ca(2+), skeletal muscle function is highly dependent on communication between two major intracellular organelles: mitochondria and sarcoplasmic reticulum (SR). In adult skeletal muscle, mitochondria located within the I-band of the sarcomere are connected to the SR by small ∼10 nm electron dense tethers that bridge the outer mitochondrial membrane to the region of SR that is ∼130 nm from the site of Ca(2+) release. However, the molecular composition of tethers and their precise impact on mitochondrial Ca(2+) uptake in skeletal muscle is unclear. Mitofusin-2 (Mfn2) is a transmembrane GTPase present in both mitochondria and ER/SR membranes that forms trans-dimers and participates in mitochondrial fusion. Here we evaluated the role Mfn2 plays in mitochondrial morphology, localization, and functional SR-mitochondrial Ca(2+) crosstalk in adult skeletal muscle. Compared to a non-targeting (CTRL) siRNA, in vivo electroporation of 400 nM Mfn2 siRNA (Mfn2 KD) into mouse footpads resulted in a marked acute reduction (67±3%) in Mfn2 protein levels in flexor digitorum brevis (FDB) muscles that occurred without a change in other key Ca(2+) regulatory proteins. Electron microscopy analyses revealed that Mfn2 knockdown resulted in a change in mitochondria morphology and mis-localization of some mitochondria from the I-band to the A-band region of the sarcomere. To assess the role of Mfn2 in SR-mitochondrial crosstalk, we measured mitochondrial Ca(2+) uptake and myoplasmic Ca(2+) transients with rhod-2 and mag-fluo-4, respectively, during repetitive high frequency tetanic stimulation (5×100 Hz tetani, 500 ms/tetani, 0.2 duty cycle) in CTRL and Mfn2 KD fibers. Mitochondrial Ca(2+) uptake during repetitive tetanic stimulation was significantly reduced (40%) in Mfn2 KD FDB fibers, which was accompanied by a parallel elevation in the global electrically evoked myoplasmic Ca(2+) transient. Mfn2 KD also resulted in a reduction of the mitochondrial membrane potential, which contributed to the observed decrease in activity-dependent mitochondrial Ca(2+) uptake. Consistent with this idea, a similar decrease in mitochondrial Ca(2+) uptake was also observed in wild type fibers following a comparable reduction in mitochondrial membrane potential induced by acute exposure to a low concentration (50 nM) of carbonylcyanide-p-trifluoromethoxyphenylhydrazone (FCCP). In addition, both global and mitochondrial Ca(2+) transients during repetitive tetanic stimulation were similarly reduced by both slow (EGTA) and fast (BAPTA) Ca(2+) chelating agents. Together, these results indicate that Mfn2 promotes proper mitochondrial morphology, localization, and membrane potential required for optimal activity-dependent mitochondrial Ca(2+) uptake and buffering of the global myoplasmic Ca(2+) transient in adult skeletal muscle.
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Jung NY, Park YE, Shin JH, Lee CH, Jung DS, Kim DS. Mild Clinical Features and Histopathologically Atypical Cores in Two Korean Families with Central Core Disease Harboring RYR1 Mutations at the C-Terminal Region. J Clin Neurol 2014; 11:97-101. [PMID: 25628744 PMCID: PMC4302187 DOI: 10.3988/jcn.2015.11.1.97] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2013] [Revised: 10/21/2013] [Accepted: 10/22/2013] [Indexed: 12/26/2022] Open
Abstract
Background Central core disease (CCD) is a congenital myopathy characterized by distinctive cores in muscle fibers. Mutations in the gene encoding ryanodine receptor 1 (RYR1) have been identified in most CCD patients. Case Report Two unrelated patients presented with slowly progressive or nonprogressive proximal muscle weakness since childhood. Their family history revealed some members with the same clinical problem. Histological analysis of muscle biopsy samples revealed numerous peripheral cores in the muscle fibers. RYR1 sequence analysis disclosed a novel mutation in exon 101 (c.14590T>C) and confirmed a previously reported mutation in exon 102 (c.14678G>A). Conclusions We report herein two families with CCD in whom missense mutations at the C-terminal of RYR1 were identified. Although it has been accepted that such mutations are usually associated with a severe clinical phenotype and clearly demarcated central cores, our patients exhibited a mild clinical phenotype without facial muscle involvement and skeletal deformities, and atypical cores in their muscle biopsy specimens.
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Affiliation(s)
- Na-Yeon Jung
- Department of Neurology, Pusan National University Yangsan Hospital, Yangsan, Korea
| | - Yeong-Eun Park
- Department of Neurology, Pusan National University Hospital, Busan, Korea
| | - Jin-Hong Shin
- Department of Neurology, Pusan National University Yangsan Hospital, Yangsan, Korea
| | - Chang Hun Lee
- Department of Pathology, Pusan National University Hospital, Busan, Korea
| | - Dae-Soo Jung
- Department of Neurology, Pusan National University Hospital, Busan, Korea
| | - Dae-Seong Kim
- Department of Neurology, Pusan National University Yangsan Hospital, Yangsan, Korea
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Orai1-dependent calcium entry promotes skeletal muscle growth and limits fatigue. Nat Commun 2014; 4:2805. [PMID: 24241282 PMCID: PMC3868675 DOI: 10.1038/ncomms3805] [Citation(s) in RCA: 111] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2013] [Accepted: 10/22/2013] [Indexed: 11/20/2022] Open
Abstract
Store-operated Ca2+ entry (SOCE) in skeletal muscle involves signaling between stromal interaction molecule 1 (STIM1) in the sarcoplasmic reticulum and Ca2+ selective Orai1 channels in the sarcolemma. Here we generate transgenic mice with muscle-specific expression of dominant-negative Orai1 (dnOrai1) and demonstrate that Orai1-dependent SOCE promotes growth and limits fatigue in adult skeletal muscle. dnOrai1 mice lack SOCE specifically in muscle but are fertile and thrive well into adulthood. Although muscle ultrastructure, excitation-contraction coupling fiber type, and expression of other Ca2+ regulatory proteins are unaltered, dnOrai1 mice exhibit reduced body weight, muscle mass, and fiber cross-sectional area. Importantly, during intense repetitive activity, dnOrai1 mice display increased susceptibility to fatigue at the single fibre, excised muscle, and whole animal levels. We further show that STIM1 and Orai1 proteins colocalise within the triad junction but do not exist in a preassembled context. These results show that Orai1-dependent SOCE has an important physiological role in muscles of adult mice.
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Shirvanyants D, Ramachandran S, Mei Y, Xu L, Meissner G, Dokholyan NV. Pore dynamics and conductance of RyR1 transmembrane domain. Biophys J 2014; 106:2375-84. [PMID: 24896116 PMCID: PMC4052289 DOI: 10.1016/j.bpj.2014.04.023] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2014] [Accepted: 04/17/2014] [Indexed: 11/25/2022] Open
Abstract
Ryanodine receptors (RyR) are calcium release channels, playing a major role in the regulation of muscular contraction. Mutations in skeletal muscle RyR (RyR1) are associated with congenital diseases such as malignant hyperthermia and central core disease (CCD). The absence of high-resolution structures of RyR1 has limited our understanding of channel function and disease mechanisms at the molecular level. Previously, we have reported a hypothetical structure of the RyR1 pore-forming region, obtained by homology modeling and supported by mutational scans, electrophysiological measurements, and cryo-electron microscopy. Here, we utilize the expanded model encompassing six transmembrane helices to calculate the RyR1 pore region conductance, to analyze its structural stability, and to hypothesize the mechanism of the Ile4897 CCD-associated mutation. The calculated conductance of the wild-type RyR1 suggests that the proposed pore structure can sustain ion currents measured in single-channel experiments. We observe a stable pore structure on timescales of 0.2 μs, with multiple cations occupying the selectivity filter and cytosolic vestibule, but not the inner chamber. We further suggest that stability of the selectivity filter critically depends on the interactions between the I4897 residue and several hydrophobic residues of the neighboring subunit. Loss of these interactions in the case of polar substitution I4897T results in destabilization of the selectivity filter, a possible cause of the CCD-specific reduced Ca(2+) conductance.
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Affiliation(s)
- David Shirvanyants
- Department of Biochemistry and Biophysics, School of Medicine, University of North Carolina, Chapel Hill, North Carolina
| | - Srinivas Ramachandran
- Department of Biochemistry and Biophysics, School of Medicine, University of North Carolina, Chapel Hill, North Carolina
| | - Yingwu Mei
- Department of Biochemistry and Biophysics, School of Medicine, University of North Carolina, Chapel Hill, North Carolina
| | - Le Xu
- Department of Biochemistry and Biophysics, School of Medicine, University of North Carolina, Chapel Hill, North Carolina
| | - Gerhard Meissner
- Department of Biochemistry and Biophysics, School of Medicine, University of North Carolina, Chapel Hill, North Carolina.
| | - Nikolay V Dokholyan
- Department of Biochemistry and Biophysics, School of Medicine, University of North Carolina, Chapel Hill, North Carolina.
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Abstract
The advent of the polymerase chain reaction and the availability of data from various global human genome projects should make it possible, using a DNA sample isolated from white blood cells, to diagnose rapidly and accurately almost any monogenic condition resulting from single nucleotide changes. DNA-based diagnosis for malignant hyperthermia (MH) is an attractive proposition, because it could replace the invasive and morbid caffeine-halothane/in vitro contracture tests of skeletal muscle biopsy tissue. Moreover, MH is preventable if an accurate diagnosis of susceptibility can be made before general anesthesia, the most common trigger of an MH episode. Diagnosis of MH using DNA was suggested as early as 1990 when the skeletal muscle ryanodine receptor gene (RYR1), and a single point mutation therein, was linked to MH susceptibility. In 1994, a single point mutation in the α 1 subunit of the dihydropyridine receptor gene (CACNA1S) was identified and also subsequently shown to be causative of MH. In the succeeding years, the number of identified mutations in RYR1 has grown, as has the number of potential susceptibility loci, although no other gene has yet been definitively associated with MH. In addition, it has become clear that MH is associated with either of these 2 genes (RYR1 and CACNA1S) in only 50% to 70% of affected families. While DNA testing for MH susceptibility has now become widespread, it still does not replace the in vitro contracture tests. Whole exome sequence analysis makes it potentially possible to identify all variants within human coding regions, but the complexity of the genome, the heterogeneity of MH, the limitations of bioinformatic tools, and the lack of precise genotype/phenotype correlations are all confounding factors. In addition, the requirement for demonstration of causality, by in vitro functional analysis, of any familial mutation currently precludes DNA-based diagnosis as the sole test for MH susceptibility. Nevertheless, familial DNA testing for MH susceptibility is now widespread although limited to a positive diagnosis and to those few mutations that have been functionally characterized. Identification of new susceptibility genes remains elusive. When new genes are identified, it will be the role of the biochemists, physiologists, and biophysicists to devise functional assays in appropriate systems. This will remain the bottleneck unless high throughput platforms can be designed for functional work. Analysis of entire genomes from several individuals simultaneously is a reality. DNA testing for MH, based on current criteria, remains the dream.
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Affiliation(s)
- Kathryn M Stowell
- From the Institute of Fundamental Sciences, Massey University, Palmerston North, New Zealand
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Guerrero-Hernández A, Ávila G, Rueda A. Ryanodine receptors as leak channels. Eur J Pharmacol 2013; 739:26-38. [PMID: 24291096 DOI: 10.1016/j.ejphar.2013.11.016] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2013] [Accepted: 11/21/2013] [Indexed: 01/18/2023]
Abstract
Ryanodine receptors are Ca(2+) release channels of internal stores. This review focuses on those situations and conditions that transform RyRs from a finely regulated ion channel to an unregulated Ca(2+) leak channel and the pathological consequences of this alteration. In skeletal muscle, mutations in either CaV1.1 channel or RyR1 results in a leaky behavior of the latter. In heart cells, RyR2 functions normally as a Ca(2+) leak channel during diastole within certain limits, the enhancement of this activity leads to arrhythmogenic situations that are tackled with different pharmacological strategies. In smooth muscle, RyRs are involved more in reducing excitability than in stimulating contraction so the leak activity of RyRs in the form of Ca(2+) sparks, locally activates Ca(2+)-dependent potassium channels to reduce excitability. In neurons the enhanced activity of RyRs is associated with the development of different neurodegenerative disorders such as Alzheimer and Huntington diseases. It appears then that the activity of RyRs as leak channels can have both physiological and pathological consequences depending on the cell type and the metabolic condition.
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Affiliation(s)
| | | | - Angélica Rueda
- Departamento de Bioquímica, Cinvestav, Mexico city, México
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Bezprozvanny I. Bilayer measurement of endoplasmic reticulum Ca2+ channels. Cold Spring Harb Protoc 2013; 2013:2013/11/pdb.top066225. [PMID: 24184754 DOI: 10.1101/pdb.top066225] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Reconstitution of ion channels into planar lipid bilayers (also called black lipid membranes or BLM) is the most widely used method to conduct physiological studies of intracellular ion channels, including endoplasmic reticulum (ER) calcium (Ca(2+)) channels. The two main types of Ca(2+) release channels in the ER membrane are ryanodine receptors (RyanRs) and inositol(1,4,5)-trisphosphate receptors (InsP3Rs). Use of the BLM reconstitution technique enabled the initial description of the functional properties of InsP3R and RyanR at the single-channel level more than 20 years ago. Since then, BLM reconstitution methods have been used to study physiological modulation and to perform structure-function analysis of these channels, and to study pathological changes in the function of InsP3R and RyanR in various disease states. The BLM technique has also been useful for studies of other intracellular Ca(2+) channels, such as ER Ca(2+) leak presenilin channels and NAADP-gated lysosomal Ca(2+) channels encoded by TPC2. In this article, basic protocols used for BLM studies of ER Ca(2+) channels are introduced.
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Affiliation(s)
- Ilya Bezprozvanny
- Department of Physiology, University of Texas Southwestern Medical Center, Dallas, Texas 75390
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Skeletal muscle ryanodine receptor mutations associated with malignant hyperthermia showed enhanced intensity and sensitivity to triggering drugs when expressed in human embryonic kidney cells. Anesthesiology 2013; 119:111-8. [PMID: 23459219 DOI: 10.1097/aln.0b013e31828cebfe] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
BACKGROUND Mutations within the gene encoding the skeletal muscle calcium channel ryanodine receptor can result in malignant hyperthermia. Although it is important to characterize the functional effects of candidate mutations to establish a genetic test for diagnosis, ex vivo methods are limited because of the low incidence of the disorder and sample unavailability. More than 250 candidate mutations have been identified, but only a few mutations have been functionally characterized. METHODS The human skeletal muscle ryanodine receptor complementary DNA was cloned with or without a disease-related variant. Wild-type and mutant calcium channel proteins were transiently expressed in human embryonic kidney-293 cells expressing the large T-antigen of simian virus 40, and functional analysis was carried out using calcium imaging with fura-2 AM. Six human malignant hyperthermia-related mutants such as R44C, R163C, R401C, R533C, R533H, and H4833Y were analyzed. Cells were stimulated with a specific ryanodine receptor agonist 4-chloro-m-cresol, and intracellular calcium mobility was analyzed to determine the functional aspects of mutant channels. RESULTS Mutant proteins that contained a variant linked to malignant hyperthermia showed higher sensitivity to the agonist. Compared with the wild type (EC50=453.2 µM, n=18), all six mutants showed a lower EC50 (21.2-170.4 µM, n=12-23), indicating susceptibility against triggering agents. CONCLUSIONS These six mutations cause functional abnormality of the calcium channel, leading to higher sensitivity to a specific agonist, and therefore could be considered potentially causative of malignant hyperthermia reactions.
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Gellerich FN, Gizatullina Z, Gainutdinov T, Muth K, Seppet E, Orynbayeva Z, Vielhaber S. The control of brain mitochondrial energization by cytosolic calcium: the mitochondrial gas pedal. IUBMB Life 2013; 65:180-90. [PMID: 23401251 DOI: 10.1002/iub.1131] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2012] [Accepted: 12/08/2012] [Indexed: 11/05/2022]
Abstract
This review focuses on problems of the intracellular regulation of mitochondrial function in the brain via the (i) supply of mitochondria with ADP by means of ADP shuttles and channels and (ii) the Ca(2+) control of mitochondrial substrate supply. The permeability of the mitochondrial outer membrane for adenine nucleotides is low. Therefore rate dependent concentration gradients exist between the mitochondrial intermembrane space and the cytosol. The existence of dynamic ADP gradients is an important precondition for the functioning of ADP shuttles, for example CrP-shuttle. Cr at mM concentrations instead of ADP diffuses from the cytosol through the porin pores into the intermembrane space. The CrP-shuttle isoenzymes work in different directions which requires different metabolite concentrations mainly caused by dynamic ADP compartmentation. The ADP shuttle mechanisms alone cannot explain the load dependent changes in mitochondrial energization, and a complete model of mitochondrial regulation have to account the Ca(2+) -dependent substrate supply too. According to the old paradigmatic view, Ca(2+) (cyt) taken up by the mitochondrial Ca(2+) uniporter activates dehydrogenases within the matrix. However, recently it was found that Ca(2+) (cyt) at low nM concentrations exclusively activates the state 3 respiration via aralar, the mitochondrial glutamate/aspartate carrier. At higher Ca(2+) (cyt) (> 500 nM), brain mitochondria take up Ca(2+) for activation of substrate oxidation rates. Since brain mitochondrial pyruvate oxidation is only slightly influenced by Ca(2+) (cyt) , it was proposed that the cytosolic formation of pyruvate from its precursors is tightly controlled by the Ca(2+) dependent malate/aspartate shuttle. At low (50-100 nM) Ca(2+) (cyt) the pyruvate formation is suppressed, providing a substrate limitation control in neurons. This so called "gas pedal" mechanism explains why the energy metabolism of neurons in the nucleus suprachiasmaticus could be down-regulated at night but activated at day as a basis for the circadian changes in Ca(2+) (cyt) . It also could explain the energetic disadvantages caused by altered Ca(2+) (cyt) at mitochondrial diseases and neurodegeneration.
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Affiliation(s)
- Frank Norbert Gellerich
- Leibniz Institute for Neurobiology Magdeburg, Department of Behavioral Neurology, 39118 Magdeburg, Germany.
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Lefebvre R, Legrand C, Groom L, Dirksen RT, Jacquemond V. Ca2+ release in muscle fibers expressing R4892W and G4896V type 1 ryanodine receptor disease mutants. PLoS One 2013; 8:e54042. [PMID: 23308296 PMCID: PMC3538700 DOI: 10.1371/journal.pone.0054042] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2012] [Accepted: 12/05/2012] [Indexed: 12/17/2022] Open
Abstract
The large and rapidly increasing number of potentially pathological mutants in the type 1 ryanodine receptor (RyR1) prompts the need to characterize their effects on voltage-activated sarcoplasmic reticulum (SR) Ca2+ release in skeletal muscle. Here we evaluated the function of the R4892W and G4896V RyR1 mutants, both associated with central core disease (CCD) in humans, in myotubes and in adult muscle fibers. For both mutants expressed in RyR1-null (dyspedic) myotubes, voltage-gated Ca2+ release was absent following homotypic expression and only partially restored following heterotypic expression with wild-type (WT) RyR1. In muscle fibers from adult WT mice, both mutants were expressed in restricted regions of the fibers with a pattern consistent with triadic localization. Voltage-clamp-activated confocal Ca2+ signals showed that fiber regions endowed with G4896V-RyR1s exhibited an ∼30% reduction in the peak rate of SR Ca2+ release, with no significant change in SR Ca2+ content. Immunostaining revealed no associated change in the expression of either α1S subunit (Cav1.1) of the dihydropyridine receptor (DHPR) or type 1 sarco(endo)plasmic reticulum Ca2+ ATPase (SERCA1), indicating that the reduced Ca2+ release resulted from defective RyR1 function. Interestingly, in spite of robust localized junctional expression, the R4892W mutant did not affect SR Ca2+ release in adult muscle fibers, consistent with a low functional penetrance of this particular CCD-associated mutant.
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Affiliation(s)
- Romain Lefebvre
- Centre de Génétique et de Physiologie Moléculaire et Cellulaire, CNRS UMR 5534 – Université Lyon 1, Villeurbanne, France
| | - Claude Legrand
- Centre de Génétique et de Physiologie Moléculaire et Cellulaire, CNRS UMR 5534 – Université Lyon 1, Villeurbanne, France
| | - Linda Groom
- Department of Pharmacology and Physiology, University of Rochester Medical Center, Rochester, New York, United States of America
| | - Robert T. Dirksen
- Department of Pharmacology and Physiology, University of Rochester Medical Center, Rochester, New York, United States of America
| | - Vincent Jacquemond
- Centre de Génétique et de Physiologie Moléculaire et Cellulaire, CNRS UMR 5534 – Université Lyon 1, Villeurbanne, France
- * E-mail:
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Liu Q, Bian W, Shi H, Fan L, Shuang S, Dong C, Choi MMF. A novel ratiometric emission probe for Ca2+in living cells. Org Biomol Chem 2013. [DOI: 10.1039/c2ob26888d] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
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Kraeva N, Zvaritch E, Rossi AE, Goonasekera SA, Zaid H, Frodis W, Kraev A, Dirksen RT, Maclennan DH, Riazi S. Novel excitation-contraction uncoupled RYR1 mutations in patients with central core disease. Neuromuscul Disord 2012. [PMID: 23183335 DOI: 10.1016/j.nmd.2012.08.007] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Central core disease, one of the most common congenital myopathies in humans, has been linked to mutations in the RYR1 gene encoding the Ca(2+) release channel of the sarcoplasmic reticulum (RyR1). Functional analyses showed that disease-associated RYR1 mutations led to impairment of skeletal muscle Ca(2+) homeostasis; however, thorough understanding of the molecular mechanisms underlying central core disease and other RyR1-related conditions is still lacking. We screened by sequencing the complete RYR1 transcripts in ten unrelated patients with central core disease and identified five novel, p.M4640R, p.L4647P, p.F4808L, p.D4918N and p.F4941C, and four recurrent mutations. Four of the novel mutations involved amino acid residues that were positioned within putative transmembrane segments of the RyR1. The pathogenic character of the identified mutations was demonstrated by bioinformatic analyses and by the in vitro functional studies in HEK293 cells and RYR1-null (dyspedic) myotubes. Characterization of Ca(2+) channel properties of RyR1s carrying one recurrent and two novel mutations upholds the view that diminished intracellular Ca(2+) release caused by impaired Ca(2+) channel gating and/or Ca(2+) permeability is an important component of central core disease etiology. This study expands the list of functionally characterized disease-associated RyR1 mutations, increasing the value of genetic diagnosis for RyR1-related disorders.
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Affiliation(s)
- Natalia Kraeva
- Malignant Hyperthermia Investigation Unit, Toronto General Hospital, University Health Network, Toronto, ON, Canada M5G 2C4
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Allele-specific gene silencing in two mouse models of autosomal dominant skeletal myopathy. PLoS One 2012; 7:e49757. [PMID: 23152933 PMCID: PMC3495761 DOI: 10.1371/journal.pone.0049757] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2012] [Accepted: 10/17/2012] [Indexed: 12/16/2022] Open
Abstract
We explored the potential of mutant allele-specific gene silencing (ASGS) in providing therapeutic benefit in two established mouse models of the autosomal dominantly-inherited muscle disorders, Malignant Hyperthermia (MH) and Central Core Disease (CCD). Candidate ASGS siRNAs were designed and validated for efficacy and specificity on ryanodine receptor (RyR1) cDNA mini-constructs expressed in HEK293 cells using RT-PCR- and confocal microscopy-based assays. In vivo delivery of the most efficacious identified siRNAs into flexor digitorum brevis (FDB) muscles was achieved by injection/electroporation of footpads of 4–6 month old heterozygous Ryr1Y524S/+ (YS/+) and Ryr1I4895T/+ (IT/+) knock-in mice, established mouse models of MH with cores and CCD, respectively. Treatment of IT/+ mice resulted in a modest rescue of deficits in the maximum rate (∼38% rescue) and magnitude (∼78%) of ligand-induced Ca2+ release that occurred in the absence of a change in the magnitude of electrically-evoked Ca2+ release. Compared to the difference between the caffeine sensitivity of Ca2+ release in FDB fibers from YS/+ and WT mice treated with SCR siRNA (EC50: 1.1 mM versus 4.4 mM, respectively), caffeine sensitivity was normalized in FDB fibers from YS/+ mice following 2 (EC50: 2.8 mM) and 4 week (EC50: 6.6 mM) treatment with YS allele-specific siRNA. Moreover, the temperature-dependent increase in resting Ca2+ observed in FDB fibers from YS/+ mice was normalized to WT levels after 2 weeks of treatment with YS allele-specific siRNA. As determined by quantitative real time PCR, the degree of functional rescue in YS/+ and IT/+ mice correlated well with the relative increase in fractional WT allele expression.
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Wu CY, Chen YF, Wang CH, Kao CH, Zhuang HW, Chen CC, Chen LK, Kirby R, Wei YH, Tsai SF, Tsai TF. A persistent level of Cisd2 extends healthy lifespan and delays aging in mice. Hum Mol Genet 2012; 21:3956-68. [PMID: 22661501 DOI: 10.1093/hmg/dds210] [Citation(s) in RCA: 76] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
The CISD2 gene, which is an evolutionarily conserved novel gene, encodes a transmembrane protein primarily associated with the mitochondrial outer membrane. Significantly, the CISD2 gene is located within the candidate region on chromosome 4q where a genetic component for human longevity has been mapped. Previously, we have shown that Cisd2 deficiency shortens lifespan resulting in premature aging in mice. Additionally, an age-dependent decrease in Cisd2 expression has been detected during normal aging. In this study, we demonstrate that a persistent level of Cisd2 achieved by transgenic expression in mice extends their median and maximum lifespan without any apparent deleterious side effects. Cisd2 also ameliorates age-associated degeneration of the skin, skeletal muscles and neurons. Moreover, Cisd2 protects mitochondria from age-associated damage and functional decline as well as attenuating the age-associated reduction in whole-body energy metabolism. These results suggest that Cisd2 is a fundamentally important regulator of lifespan and provide an experimental basis for exploring the candidacy of CISD2 in human longevity.
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Affiliation(s)
- Chia-Yu Wu
- Department of Life Sciences and Institute of Genome Sciences, National Yang-Ming University, Taipei 112, Taiwan
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Jungbluth H, Dowling JJ, Ferreiro A, Muntoni F. 182nd ENMC International Workshop: RYR1-related myopathies, 15-17th April 2011, Naarden, The Netherlands. Neuromuscul Disord 2012; 22:453-62. [PMID: 22226685 DOI: 10.1016/j.nmd.2011.12.003] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2011] [Accepted: 12/04/2011] [Indexed: 11/15/2022]
Affiliation(s)
- Heinz Jungbluth
- Clinical Neuroscience Division, IOP, King's College, London, United Kingdom.
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