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Pearce L, Meizoso-Huesca A, Seng C, Lamboley CR, Singh DP, Launikonis BS. Ryanodine receptor activity and store-operated Ca 2+ entry: Critical regulators of Ca 2+ content and function in skeletal muscle. J Physiol 2023; 601:4183-4202. [PMID: 35218018 DOI: 10.1113/jp279512] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2021] [Accepted: 01/28/2022] [Indexed: 11/08/2022] Open
Abstract
Store-operated Ca2+ entry (SOCE) is critical to cell function. In skeletal muscle, SOCE has evolved alongside excitation-contraction coupling (EC coupling); as a result, it displays unique properties compared to SOCE in other cells. The plasma membrane of skeletal muscle is mostly internalized as the tubular system, with the tubules meeting the sarcoplasmic reticulum (SR) terminal cisternae, forming junctions where the proteins that regulate EC coupling and SOCE are positioned. In this review, we describe the properties and roles of SOCE based on direct measurements of Ca2+ influx during SR Ca2+ release and leak. SOCE is activated immediately and locally as the [Ca2+ ] of the junctional SR terminal cisternae ([Ca2+ ]jSR ) depletes. [Ca2+ ]jSR changes rapidly and steeply with increasing activity of the SR ryanodine receptor isoform 1 (RyR1). The high fidelity of [Ca2+ ]jSR with RyR1 activity probably depends on the SR Ca2+ -buffer calsequestrin that is located immediately behind RyR1 inside the SR. This arrangement provides in-phase activation and deactivation of SOCE with a large dynamic range, allowing precise grading of SOCE flux. The in-phase activation of SOCE as the SR partially depletes traps Ca2+ in the cytoplasm, preventing net Ca2+ loss. Mild presentation of RyR1 leak can occur under physiological conditions, providing fibre Ca2+ redistribution without changing fibre Ca2+ content. This condition preserves normal contractile function at the same time as increasing basal metabolic rate. However, higher RyR1 leak drives excess cytoplasmic and mitochondrial Ca2+ load, setting a deleterious intracellular environment that compromises the function of the skeletal muscle.
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Affiliation(s)
- Luke Pearce
- School of Biomedical Sciences, The University of Queensland, Brisbane, QLD, Australia
| | - Aldo Meizoso-Huesca
- School of Biomedical Sciences, The University of Queensland, Brisbane, QLD, Australia
| | - Crystal Seng
- School of Biomedical Sciences, The University of Queensland, Brisbane, QLD, Australia
| | - Cedric R Lamboley
- School of Biomedical Sciences, The University of Queensland, Brisbane, QLD, Australia
| | - Daniel P Singh
- School of Biomedical Sciences, The University of Queensland, Brisbane, QLD, Australia
| | - Bradley S Launikonis
- School of Biomedical Sciences, The University of Queensland, Brisbane, QLD, Australia
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2
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O’Connor TN, Zhao N, Orciuoli HM, Brasile A, Pietrangelo L, He M, Groom L, Leigh J, Mahamed Z, Liang C, Malik S, Protasi F, Dirksen RT. Voluntary wheel running mitigates disease in an Orai1 gain-of-function mouse model of tubular aggregate myopathy. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.09.29.559036. [PMID: 37808709 PMCID: PMC10557777 DOI: 10.1101/2023.09.29.559036] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/10/2023]
Abstract
Tubular aggregate myopathy (TAM) is an inherited skeletal muscle disease associated with progressive muscle weakness, cramps, and myalgia. Tubular aggregates (TAs) are regular arrays of highly ordered and densely packed SR straight-tubes in muscle biopsies; the extensive presence of TAs represent a key histopathological hallmark of this disease in TAM patients. TAM is caused by gain-of-function mutations in proteins that coordinate store-operated Ca2+ entry (SOCE): STIM1 Ca2+ sensor proteins in the sarcoplasmic reticulum (SR) and Ca2+-permeable ORAI1 channels in the surface membrane. We have previously shown that voluntary wheel running (VWR) prevents formation of TAs in aging mice. Here, we assessed the therapeutic potential of endurance exercise (in the form of VWR) in mitigating the functional and structural alterations in a knock-in mouse model of TAM (Orai1G100S/+ or GS mice) based on a gain-of-function mutation in the ORAI1 pore. WT and GS mice were singly-housed for six months (from two to eight months of age) with either free-spinning or locked low profile wheels. Six months of VWR exercise significantly increased soleus peak tetanic specific force production, normalized FDB fiber Ca2+ store content, and markedly reduced TAs in EDL muscle from GS mice. Six months of VWR exercise normalized the expression of mitochondrial proteins found to be altered in soleus muscle of sedentary GS mice in conjunction with a signature of increased protein translation and biosynthetic processes. Parallel proteomic analyses of EDL muscles from sedentary WT and GS mice revealed changes in a tight network of pathways involved in formation of supramolecular complexes, which were also normalized following six months of VWR. In summary, sustained voluntary endurance exercise improved slow twitch muscle function, reduced the presence of TAs in fast twitch muscle, and normalized the muscle proteome of GS mice consistent with protective adaptions in proteostasis, mitochondrial structure/function, and formation of supramolecular complexes.
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Affiliation(s)
- Thomas N. O’Connor
- Department of Biomedical Genetics, Genetics and Genomics Graduate Program, University of Rochester Medical Center, Rochester, NY, USA
- Department of Pharmacology and Physiology, University of Rochester Medical Center, Rochester, NY, USA
| | - Nan Zhao
- Department of Pharmacology and Physiology, University of Rochester Medical Center, Rochester, NY, USA
| | - Haley M. Orciuoli
- Department of Pharmacology and Physiology, University of Rochester Medical Center, Rochester, NY, USA
- Department of Biology, Biological Sciences, University of Rochester, Rochester, NY, USA
| | - Alice Brasile
- CAST, Center for Advanced Studies and Technology & DMSI, Department of Medicine and Aging Sciences, University G. d’Annunzio of Chieti-Pescara, I-66100 Chieti, Italy
| | - Laura Pietrangelo
- CAST, Center for Advanced Studies and Technology & DMSI, Department of Medicine and Aging Sciences, University G. d’Annunzio of Chieti-Pescara, I-66100 Chieti, Italy
| | - Miao He
- Department of Pharmacology and Physiology, University of Rochester Medical Center, Rochester, NY, USA
| | - Linda Groom
- Department of Pharmacology and Physiology, University of Rochester Medical Center, Rochester, NY, USA
| | - Jennifer Leigh
- Department of Pharmacology and Physiology, University of Rochester Medical Center, Rochester, NY, USA
| | - Zahra Mahamed
- Department of Pharmacology and Physiology, University of Rochester Medical Center, Rochester, NY, USA
| | - Chen Liang
- Department of Pharmacology and Physiology, University of Rochester Medical Center, Rochester, NY, USA
| | - Sundeep Malik
- Department of Pharmacology and Physiology, University of Rochester Medical Center, Rochester, NY, USA
| | - Feliciano Protasi
- CAST, Center for Advanced Studies and Technology & DMSI, Department of Medicine and Aging Sciences, University G. d’Annunzio of Chieti-Pescara, I-66100 Chieti, Italy
| | - Robert T. Dirksen
- Department of Pharmacology and Physiology, University of Rochester Medical Center, Rochester, NY, USA
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3
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Michelucci A, Pietrangelo L, Rastelli G, Protasi F, Dirksen RT, Boncompagni S. Constitutive assembly of Ca2+ entry units in soleus muscle from calsequestrin knockout mice. J Gen Physiol 2022; 154:213542. [PMID: 36222861 PMCID: PMC9565155 DOI: 10.1085/jgp.202213114] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2022] [Revised: 07/05/2022] [Accepted: 07/27/2022] [Indexed: 12/25/2022] Open
Abstract
Calcium (Ca2+) entry units (CEUs) are junctions within the I band of the sarcomere between stacks of sarcoplasmic reticulum (SR) cisternae and extensions of the transverse (T)-tubule. CEUs contain STIM1 and Orai1 proteins, the molecular machinery of store-operated Ca2+ entry (SOCE). In extensor digitorum longus (EDL) fibers of wild-type (WT) mice, CEUs transiently assemble during acute exercise and disassemble several hours thereafter. By contrast, calsequestrin-1 (CASQ1) ablation induces a compensatory constitutive assembly of CEUs in EDL fibers, resulting in enhanced constitutive and maximum SOCE that counteracts SR Ca2+ depletion during repetitive activity. However, whether CEUs form in slow-twitch fibers, which express both the skeletal CASQ1 and the cardiac CASQ2 isoforms, is unknown. Herein, we compared the structure and function of soleus muscles from WT and knockout mice that lack either CASQ1 (CASQ1-null) or both CASQs (dCASQ-null). Ultrastructural analyses showed that SR/T-tubule junctions at the I band, virtually identical to CEUs in EDL muscle, were present and more frequent in CASQ1-null than WT mice, with dCASQ-null exhibiting the highest incidence. The greater incidence of CEUs in soleus from dCASQ-null mice correlated with increased specific force production during repetitive, high-frequency stimulation, which depended on Ca2+ entry. Consistent with this, Orai1 expression was significantly increased in soleus of CASQ1-null mice, but even more in dCASQ-null mice, compared with WT. Together, these results strengthen the concept that CEU assembly strongly depends on CASQ expression and provides an alternative source of Ca2+ needed to refill SR Ca2+ stores to maintain specific force production during sustained muscle activity.
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Affiliation(s)
- Antonio Michelucci
- Center for Advanced Studies and Technology, University G. d'Annunzio of Chieti-Pescara, Chieti, Italy.,Department of Chemistry, Biology, and Biotechnology, University of Perugia, Perugia, Italy
| | - Laura Pietrangelo
- Center for Advanced Studies and Technology, University G. d'Annunzio of Chieti-Pescara, Chieti, Italy.,Department of Medicine and Aging Sciences, University G. d'Annunzio of Chieti-Pescara, Chieti, Italy
| | - Giorgia Rastelli
- Center for Advanced Studies and Technology, University G. d'Annunzio of Chieti-Pescara, Chieti, Italy
| | - Feliciano Protasi
- Center for Advanced Studies and Technology, University G. d'Annunzio of Chieti-Pescara, Chieti, Italy.,Department of Medicine and Aging Sciences, University G. d'Annunzio of Chieti-Pescara, Chieti, Italy
| | - Robert T Dirksen
- Department of Pharmacology and Physiology, School of Medicine and Dentistry, University of Rochester, Rochester, NY
| | - Simona Boncompagni
- Center for Advanced Studies and Technology, University G. d'Annunzio of Chieti-Pescara, Chieti, Italy.,Department of Neuroscience, Imaging, and Clinical Sciences, University G. D'Annunzio of Chieti-Pescara, Chieti, Italy
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4
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Bachmann C, Franchini M, Van den Bersselaar LR, Kruijt N, Voermans NC, Bouman K, Kamsteeg EJ, Knop KC, Ruggiero L, Santoro L, Nevo Y, Wilmshurst J, Vissing J, Sinnreich M, Zorzato D, Muntoni F, Jungbluth H, Zorzato F, Treves S. Targeted transcript analysis in muscles from patients with genetically diverse congenital myopathies. Brain Commun 2022; 4:fcac224. [PMID: 36196089 PMCID: PMC9525005 DOI: 10.1093/braincomms/fcac224] [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: 01/08/2022] [Revised: 06/29/2022] [Accepted: 09/01/2022] [Indexed: 11/17/2022] Open
Abstract
Congenital myopathies are a group of early onset muscle diseases of variable severity often with characteristic muscle biopsy findings and involvement of specific muscle types. The clinical diagnosis of patients typically relies on histopathological findings and is confirmed by genetic analysis. The most commonly mutated genes encode proteins involved in skeletal muscle excitation–contraction coupling, calcium regulation, sarcomeric proteins and thin–thick filament interaction. However, mutations in genes encoding proteins involved in other physiological functions (for example mutations in SELENON and MTM1, which encode for ubiquitously expressed proteins of low tissue specificity) have also been identified. This intriguing observation indicates that the presence of a genetic mutation impacts the expression of other genes whose product is important for skeletal muscle function. The aim of the present investigation was to verify if there are common changes in transcript and microRNA expression in muscles from patients with genetically heterogeneous congenital myopathies, focusing on genes encoding proteins involved in excitation–contraction coupling and calcium homeostasis, sarcomeric proteins, transcription factors and epigenetic enzymes. Our results identify RYR1, ATPB2B and miRNA-22 as common transcripts whose expression is decreased in muscles from congenital myopathy patients. The resulting protein deficiency may contribute to the muscle weakness observed in these patients. This study also provides information regarding potential biomarkers for monitoring disease progression and response to pharmacological treatments in patients with congenital myopathies.
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Affiliation(s)
- Christoph Bachmann
- Department of Biomedicine, Basel University Hospital , Hebelstrasse 20, Basel 4031 , Switzerland
- Department of Neurology, Basel University Hospital , Hebelstrasse 20, Basel 4031 , Switzerland
| | - Martina Franchini
- Department of Biomedicine, Basel University Hospital , Hebelstrasse 20, Basel 4031 , Switzerland
- Department of Neurology, Basel University Hospital , Hebelstrasse 20, Basel 4031 , Switzerland
| | - Luuk R Van den Bersselaar
- Department of Anesthesiology, Malignant Hyperthermia Investigation Unit, Canisius Wilhelmina Hospital , Nijmegen , The Netherlands
- Department of Neurology, Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center , Nijmegen , The Netherlands
| | - Nick Kruijt
- Department of Neurology, Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center , Nijmegen , The Netherlands
| | - Nicol C Voermans
- Department of Neurology, Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center , Nijmegen , The Netherlands
| | - Karlijn Bouman
- Department of Neurology, Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center , Nijmegen , The Netherlands
- Department of Pediatric Neurology, Donders Institute for Brain, Cognition and Behaviour, Amalia Children’s Hospital, Radboud University Medical Center , Nijmegen , The Netherlands
| | - Erik-Jan Kamsteeg
- Department of Clinical Genetics, Radboud Institute for Molecular Life Sciences, Radboud University, Nijmegen Medical Centre , Nijmegen , The Netherlands
| | - Karl Christian Knop
- Muskelhistologisches Labor, Neurologische Abteilung, Asklepios Klinik St. Georg , Lohmuehlenstraße 5, Hamburg 20099 , Germany
| | - Lucia Ruggiero
- Dipartimento di Neuroscienze, Scienze Riproduttive ed Odontostomatologiche, Università degli Studi di Napoli Federico II , Via Pansini 5, Napoli 80131 , Italy
| | - Lucio Santoro
- Dipartimento di Neuroscienze, Scienze Riproduttive ed Odontostomatologiche, Università degli Studi di Napoli Federico II , Via Pansini 5, Napoli 80131 , Italy
| | - Yoram Nevo
- Institute of Neurology, Schneider Children’s Medical Center of Israel , Petah Tiqva , Israel
| | - Jo Wilmshurst
- Paediatric Neurology, Red Cross War Memorial Children’s Hospital, Neuroscience Institute, University of Cape Town , Cape Town , South Africa
| | - John Vissing
- Department of Neurology, section 8077, Rigshospitalet, University of Copenhagen , Blegdamsvej 9, Copenhagen DK-2100 , Denmark
| | - Michael Sinnreich
- Department of Biomedicine, Basel University Hospital , Hebelstrasse 20, Basel 4031 , Switzerland
- Department of Neurology, Basel University Hospital , Hebelstrasse 20, Basel 4031 , Switzerland
| | - Daniele Zorzato
- GKT School of Medical Education, King’s College London , Hodgkin Building, Newcomen Street, London SE1 1UL , UK
| | - Francesco Muntoni
- Dubowitz Neuromuscular Centre and MRC Centre for Neuromuscular Diseases, UCL, Institute of Child Health , London , UK
- NIHR Great Ormond Street Hospital Biomedical Research Centre , London , UK
| | - Heinz Jungbluth
- Department of Paediatric Neurology, Neuromuscular Service, Evelina Children’s Hospital, St. Thomas’ Hospital , London , UK
- Department of Basic and Clinical Neuroscience, Institute of Psychiatry, Psychology and Neuroscience (IoPPN), King’s College London , London , UK
- Randall Center for Cell and Molecular Biophysics, Muscle Signalling Section, Faculty of Life Sciences and Medicine, King’s College , London , UK
| | - Francesco Zorzato
- Department of Biomedicine, Basel University Hospital , Hebelstrasse 20, Basel 4031 , Switzerland
- Department of Neurology, Basel University Hospital , Hebelstrasse 20, Basel 4031 , Switzerland
- Department of Life Science and Biotechnology, University of Ferrara , Via Borsari 46, Ferrara 44100 , Italy
| | - Susan Treves
- Department of Biomedicine, Basel University Hospital , Hebelstrasse 20, Basel 4031 , Switzerland
- Department of Neurology, Basel University Hospital , Hebelstrasse 20, Basel 4031 , Switzerland
- Department of Life Science and Biotechnology, University of Ferrara , Via Borsari 46, Ferrara 44100 , Italy
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5
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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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6
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Barclay CJ, Launikonis BS. A mathematical model to quantify RYR Ca2+ leak and associated heat production in resting human skeletal muscle fibers. J Gen Physiol 2022; 154:213077. [PMID: 35311921 PMCID: PMC9037342 DOI: 10.1085/jgp.202112994] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2021] [Accepted: 02/06/2022] [Indexed: 02/02/2023] Open
Abstract
Cycling of Ca2+ between the sarcoplasmic reticulum (SR) and myoplasm is an important component of skeletal muscle resting metabolism. As part of this cycle, Ca2+ leaks from the SR into the myoplasm and is pumped back into the SR using ATP, which leads to the consumption of O2 and generation of heat. Ca2+ may leak through release channels or ryanodine receptors (RYRs). RYR Ca2+ leak can be monitored in a skinned fiber preparation in which leaked Ca2+ is pumped into the t-system and measured with a fluorescent dye. However, accurate quantification faces a number of hurdles. To overcome them, we developed a mathematical model of Ca2+ movement in these preparations. The model incorporated Ca2+ pumps that move Ca2+ from the myoplasm to the SR and from the junctional space (JS) to the t-system, Ca2+ buffering by EGTA in the JS and myoplasm and by buffers in the SR, and Ca2+ leaks from the SR into the JS and myoplasm and from the t-system into the myoplasm. The model accurately simulated Ca2+ uptake into the t-system, the relationship between myoplasmic [Ca2+] and steady-state t-system [Ca2+], and the effect of blocking RYR Ca2+ leak on t-system Ca2+ uptake. The magnitude of the leak through the RYRs would contribute ∼5% of the resting heat production of human muscle. In normal resting fibers, RYR Ca2+ leak makes a small contribution to resting metabolism. RYR-focused pathologies have the potential to increase RYR Ca2+ leak and the RYR leak component of resting metabolism.
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7
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Tabuchi A, Tanaka Y, Takagi R, Shirakawa H, Shibaguchi T, Sugiura T, Poole DC, Kano Y. Ryanodine receptors mediate high intracellular Ca 2+ and some myocyte damage following eccentric contractions in rat fast-twitch skeletal muscle. Am J Physiol Regul Integr Comp Physiol 2022; 322:R14-R27. [PMID: 34755549 DOI: 10.1152/ajpregu.00166.2021] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2021] [Accepted: 11/05/2021] [Indexed: 11/22/2022]
Abstract
Eccentric contractions (ECC) facilitate cytosolic calcium ion (Ca2+) release from the sarcoplasmic reticulum (SR) and Ca2+ influx from the extracellular space. Ca2+ is a vital signaling messenger that regulates multiple cellular processes via its spatial and temporal concentration ([Ca2+]i) dynamics. We hypothesized that 1) a specific pattern of spatial/temporal intramyocyte Ca2+ dynamics portends muscle damage following ECC and 2) these dynamics would be regulated by the ryanodine receptor (RyR). [Ca2+]i in the tibialis anterior muscles of anesthetized adult Wistar rats was measured by ratiometric (i.e., ratio, R, 340/380 nm excitation) in vivo bioimaging with Fura-2 pre-ECC and at 5 and 24 h post-ECC (5 × 40 contractions). Separate groups of rats received RyR inhibitor dantrolene (DAN; 10 mg/kg ip) immediately post-ECC (+DAN). Muscle damage was evaluated by histological analysis on hematoxylin-eosin stained muscle sections. Compared with control (CONT, no ECC), [Ca2+]i distribution was heterogeneous with increased percent total area of high [Ca2+]i sites (operationally defined as R ≥ 1.39, i.e., ≥1 SD of mean control) 5 h post-ECC (CONT, 14.0 ± 8.0; ECC5h: 52.0 ± 7.4%, P < 0.01). DAN substantially reduced the high [Ca2+]i area 5 h post-ECC (ECC5h + DAN: 6.4 ± 3.1%, P < 0.01) and myocyte damage (ECC24h, 63.2 ± 1.0%; ECC24h + DAN: 29.1 ± 2.2%, P < 0.01). Temporal and spatially amplified [Ca2+]i fluctuations occurred regardless of DAN (ECC vs. ECC + DAN, P > 0.05). These results suggest that the RyR-mediated local high [Ca2+]i itself is related to the magnitude of muscle damage, whereas the [Ca2+]i fluctuation is an RyR-independent phenomenon.
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Affiliation(s)
- Ayaka Tabuchi
- Department of Engineering Science, Bioscience and Technology Program, University of Electro-Communications, Chofu, Japan
- Research Fellowship for Young Scientists, Japan Society for the Promotion of Science, Tokyo, Japan
| | - Yoshinori Tanaka
- Department of Engineering Science, Bioscience and Technology Program, University of Electro-Communications, Chofu, Japan
- Center for Neuroscience and Biomedical Engineering, University of Electro-Communications, Chofu, Japan
| | - Ryo Takagi
- Department of Engineering Science, Bioscience and Technology Program, University of Electro-Communications, Chofu, Japan
- Research Fellowship for Young Scientists, Japan Society for the Promotion of Science, Tokyo, Japan
| | - Hideki Shirakawa
- Department of Engineering Science, Bioscience and Technology Program, University of Electro-Communications, Chofu, Japan
| | - Tsubasa Shibaguchi
- Institute of Liberal Arts and Science, Kanazawa University, Kanazawa, Japan
| | - Takao Sugiura
- Department of Exercise and Health Sciences, Faculty of Education, Yamaguchi University, Yamaguchi, Japan
| | - David C Poole
- Departments of Anatomy & Physiology and Kinesiology, Kansas State University, Manhattan, Kansas
| | - Yutaka Kano
- Department of Engineering Science, Bioscience and Technology Program, University of Electro-Communications, Chofu, Japan
- Center for Neuroscience and Biomedical Engineering, University of Electro-Communications, Chofu, Japan
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8
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Sztretye M, Singlár Z, Balogh N, Kis G, Szentesi P, Angyal Á, Balatoni I, Csernoch L, Dienes B. The Role of Orai1 in Regulating Sarcoplasmic Calcium Release, Mitochondrial Morphology and Function in Myostatin Deficient Skeletal Muscle. Front Physiol 2021; 11:601090. [PMID: 33408641 PMCID: PMC7779810 DOI: 10.3389/fphys.2020.601090] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2020] [Accepted: 12/02/2020] [Indexed: 11/28/2022] Open
Abstract
In mice a naturally occurring 12-bp deletion in the myostatin gene is considered responsible for the compact phenotype (MstnCmpt–dl1Abc, Cmpt) labeled by a tremendous increase in body weight along with signs of muscle weakness, easier fatigability, decreased Orai1 expression and store operated calcium entry (SOCE). Here, on the one hand, Cmpt fibers were reconstructed with venus-Orai1 but this failed to restore SOCE. On the other hand, the endogenous Orai1 was silenced in fibers from wild type C57Bl6 mice which resulted in ∼70% of Orai1 being silenced in whole muscle homogenates as confirmed by Western blot, accompanied by an inhibitory effect on the voltage dependence of SR calcium release that manifested in a slight shift toward more positive potential values. This maneuver completely hampered SOCE. Our observations are consistent with the idea that Orai1 channels are present in distinct pools responsible for either a rapid refilling of the SR terminal cisternae connected to each voltage-activated calcium transient, or a slow SOCE associated with an overall depletion of calcium in the SR lumen. Furthermore, when Cmpt cells were loaded with the mitochondrial membrane potential sensitive dye TMRE, fiber segments with depolarized mitochondria were identified covering on average 26.5 ± 1.5% of the fiber area. These defective areas were located around the neuromuscular junction and displayed significantly smaller calcium transients. The ultrastructural analysis of the Cmpt fibers revealed changes in the mitochondrial morphology. In addition, the mitochondrial calcium uptake during repetitive stimulation was higher in the Cmpt fibers. Our results favor the idea that reduced function and/or expression of SOCE partners (in this study Orai1) and mitochondrial defects could play an important role in muscle weakness and degeneration associated with certain pathologies, perhaps including loss of function of the neuromuscular junction and aging.
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Affiliation(s)
- Mónika Sztretye
- Department of Physiology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - Zoltán Singlár
- Department of Physiology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - Norbert Balogh
- Department of Physiology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - Gréta Kis
- Department of Anatomy, Histology and Embryology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - Péter Szentesi
- Department of Physiology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - Ágnes Angyal
- Department of Physiology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - Ildikó Balatoni
- Department of Physiology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - László Csernoch
- Department of Physiology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - Beatrix Dienes
- Department of Physiology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
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Wang WA, Demaurex N. Proteins Interacting with STIM1 and Store-Operated Ca 2+ Entry. PROGRESS IN MOLECULAR AND SUBCELLULAR BIOLOGY 2021; 59:51-97. [PMID: 34050862 DOI: 10.1007/978-3-030-67696-4_4] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
The endoplasmic reticulum (ER) Ca2+ sensor stromal interaction molecule 1 (STIM1) interacts with ORAI Ca2+ channels at the plasma membrane to regulate immune and muscle cell function. The conformational changes underlying STIM1 activation, translocation, and ORAI1 trapping and gating, are stringently regulated by post-translational modifications and accessory proteins. Here, we review the recent progress in the identification and characterization of ER and cytosolic proteins interacting with STIM1 to control its activation and deactivation during store-operated Ca2+ entry (SOCE).
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Affiliation(s)
- Wen-An Wang
- Department of Cellular Physiology and Metabolism, University of Geneva, Geneva, Switzerland
| | - Nicolas Demaurex
- Department of Cellular Physiology and Metabolism, University of Geneva, Geneva, Switzerland.
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10
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Cully TR, Rodney GG. Nox4 - RyR1 - Nox2: Regulators of micro-domain signaling in skeletal muscle. Redox Biol 2020; 36:101557. [PMID: 32506037 PMCID: PMC7283154 DOI: 10.1016/j.redox.2020.101557] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2020] [Revised: 04/10/2020] [Accepted: 04/23/2020] [Indexed: 12/22/2022] Open
Abstract
The ability for skeletal muscle to perform optimally can be affected by the regulation of Ca2+ within the triadic junctional space at rest. Reactive oxygen species impact muscle performance due to changes in oxidative stress, damage and redox regulation of signaling cascades. The interplay between ROS and Ca2+ signaling at the triad of skeletal muscle is therefore important to understand as it can impact the performance of healthy and diseased muscle. Here, we aimed to examine how changes in Ca2+ and redox signaling within the junctional space micro-domain of the mouse skeletal muscle fibre alters the homeostasis of these complexes. The dystrophic mdx mouse model displays increased RyR1 Ca2+ leak and increased NAD(P)H Oxidase 2 ROS. These alterations make the mdx mouse an ideal model for understanding how ROS and Ca2+ handling impact each other. We hypothesised that elevated t-tubular Nox2 ROS increases RyR1 Ca2+ leak contributing to an increase in cytoplasmic Ca2+, which could then initiate protein degradation and impaired cellular functions such as autophagy and ER stress. We found that inhibiting Nox2 ROS did not decrease RyR1 Ca2+ leak observed in dystrophin-deficient skeletal muscle. Intriguingly, another NAD(P)H isoform, Nox4, is upregulated in mice unable to produce Nox2 ROS and when inhibited reduced RyR1 Ca2+ leak. Our findings support a model in which Nox4 ROS induces RyR1 Ca2+ leak and the increased junctional space [Ca2+] exacerbates Nox2 ROS; with the cumulative effect of disruption of downstream cellular processes that would ultimately contribute to reduced muscle or cellular performance. Nox2 ROS does not influence RyR1 Ca2+ leak in skeletal muscle. Lack of Nox2 ROS increases Nox4 expression. Nox4 ROS induces RyR1 Ca2+ leak via S-nitrosylation.
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Affiliation(s)
- Tanya R Cully
- Department of Molecular Physiology and Biophysics, Baylor College of Medicine, Houston, TX, USA
| | - George G Rodney
- Department of Molecular Physiology and Biophysics, Baylor College of Medicine, Houston, TX, USA.
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11
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Avila-Medina J, Mayoral-González I, Galeano-Otero I, Redondo PC, Rosado JA, Smani T. Pathophysiological Significance of Store-Operated Calcium Entry in Cardiovascular and Skeletal Muscle Disorders and Angiogenesis. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2020; 1131:489-504. [PMID: 31646522 DOI: 10.1007/978-3-030-12457-1_19] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Store-Operated Ca2+ Entry (SOCE) is an important Ca2+ influx pathway expressed by several excitable and non-excitable cell types. SOCE is recognized as relevant signaling pathway not only for physiological process, but also for its involvement in different pathologies. In fact, independent studies demonstrated the implication of essential protein regulating SOCE, such as STIM, Orai and TRPCs, in different pathogenesis and cell disorders, including cardiovascular disease, muscular dystrophies and angiogenesis. Compelling evidence showed that dysregulation in the function and/or expression of isoforms of STIM, Orai or TRPC play pivotal roles in cardiac hypertrophy and heart failure, vascular remodeling and hypertension, skeletal myopathies, and angiogenesis. In this chapter, we summarized the current knowledge concerning the mechanisms underlying abnormal SOCE and its involvement in some diseases, as well as, we discussed the significance of STIM, Orai and TRPC isoforms as possible therapeutic targets for the treatment of angiogenesis, cardiovascular and skeletal muscle diseases.
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Affiliation(s)
- Javier Avila-Medina
- Department of Medical Physiology and Biophysics, University of Seville, Sevilla, Spain
- Institute of Biomedicine of Seville (IBiS), University Hospital of Virgen del Rocío/CSIC/University of Seville, Sevilla, Spain
| | - Isabel Mayoral-González
- Department of Medical Physiology and Biophysics, University of Seville, Sevilla, Spain
- Institute of Biomedicine of Seville (IBiS), University Hospital of Virgen del Rocío/CSIC/University of Seville, Sevilla, Spain
- Department of Surgery, University of Seville, Sevilla, Spain
| | - Isabel Galeano-Otero
- Department of Medical Physiology and Biophysics, University of Seville, Sevilla, Spain
- Institute of Biomedicine of Seville (IBiS), University Hospital of Virgen del Rocío/CSIC/University of Seville, Sevilla, Spain
| | - Pedro C Redondo
- Department of Physiology, Cell Physiology Research Group and Institute of Molecular Pathology Biomarkers, University of Extremadura, Cáceres, Spain
| | - Juan A Rosado
- Department of Physiology, Cell Physiology Research Group and Institute of Molecular Pathology Biomarkers, University of Extremadura, Cáceres, Spain
| | - Tarik Smani
- Department of Medical Physiology and Biophysics, University of Seville, Sevilla, Spain.
- Institute of Biomedicine of Seville (IBiS), University Hospital of Virgen del Rocío/CSIC/University of Seville, Sevilla, Spain.
- CIBERCV, Madrid, Spain.
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12
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Role of STIM1/ORAI1-mediated store-operated Ca 2+ entry in skeletal muscle physiology and disease. Cell Calcium 2018; 76:101-115. [PMID: 30414508 DOI: 10.1016/j.ceca.2018.10.004] [Citation(s) in RCA: 57] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2018] [Revised: 10/23/2018] [Accepted: 10/23/2018] [Indexed: 11/23/2022]
Abstract
Store-operated Ca2+ entry (SOCE) is a Ca2+ entry mechanism activated by depletion of intracellular Ca2+ stores. In skeletal muscle, SOCE is mediated by an interaction between stromal-interacting molecule-1 (STIM1), the Ca2+ sensor of the sarcoplasmic reticulum, and ORAI1, the Ca2+-release-activated-Ca2+ (CRAC) channel located in the transverse tubule membrane. This review focuses on the molecular mechanisms and physiological role of SOCE in skeletal muscle, as well as how alterations in STIM1/ORAI1-mediated SOCE contribute to muscle disease. Recent evidence indicates that SOCE plays an important role in both muscle development/growth and fatigue. The importance of SOCE in muscle is further underscored by the discovery that loss- and gain-of-function mutations in STIM1 and ORAI1 result in an eclectic array of disorders with clinical myopathy as central defining component. Despite differences in clinical phenotype, all STIM1/ORAI1 gain-of-function mutations-linked myopathies are characterized by the abnormal accumulation of intracellular membranes, known as tubular aggregates. Finally, dysfunctional STIM1/ORAI1-mediated SOCE also contributes to the pathogenesis of muscular dystrophy, malignant hyperthermia, and sarcopenia. The picture to emerge is that tight regulation of STIM1/ORAI1-dependent Ca2+ signaling is critical for optimal skeletal muscle development/function such that either aberrant increases or decreases in SOCE activity result in muscle dysfunction.
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SOCE Is Important for Maintaining Sarcoplasmic Calcium Content and Release in Skeletal Muscle Fibers. Biophys J 2018; 113:2496-2507. [PMID: 29212003 DOI: 10.1016/j.bpj.2017.09.023] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2017] [Revised: 09/01/2017] [Accepted: 09/21/2017] [Indexed: 11/20/2022] Open
Abstract
Store-operated Ca2+ entry (SOCE) is a Ca2+-entry process activated by the depletion of intracellular stores and has an important role in many cell types. In skeletal muscle, however, its role during physiological muscle activation has been controversial. To address this question, sarcoplasmic reticulum (SR) calcium release in a mouse strain with a naturally occurring mutation in the myostatin gene (Compact (Cmpt)) leading to a hypermuscular yet reduced muscle-force phenotype was compared to that in wild-type mice. To elicit Ca2+ release from the SR of flexor digitorum brevis (FDB) fibers, either a ryanodine receptor agonist (4-chloro-meta-cresol) or depolarizing pulses were used. In muscles from Cmpt mice, endogenous protein levels of STIM1 and Orai1 were reduced, and consequently, SOCE after 4-chloro-meta-cresol-induced store depletion was suppressed. Although the voltage dependence of SR calcium release was not statistically different between wild-type and Cmpt fibers, the amount of releasable calcium was significantly reduced in the latter, indicating a smaller SR content. To assess the immediate role of SOCE in replenishing the SR calcium store, the evolution of intracellular calcium concentration during a train of long-lasting depolarizations to a maximally activating voltage was monitored. Cmpt mice exhibited a faster decline in calcium release, suggesting a compromised ability to refill the SR. A simple model that incorporates a reduced SOCE as an important partner in regulating immediate calcium influx through the surface membrane readily accounts for the steady-state reduction in SR calcium content and its more pronounced decline after calcium release.
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Bakker AJ, Cully TR, Wingate CD, Barclay CJ, Launikonis BS. Doublet stimulation increases Ca 2+ binding to troponin C to ensure rapid force development in skeletal muscle. J Gen Physiol 2017; 149:323-334. [PMID: 28209802 PMCID: PMC5339514 DOI: 10.1085/jgp.201611727] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2016] [Revised: 01/08/2017] [Accepted: 01/09/2017] [Indexed: 01/24/2023] Open
Abstract
Fast-twitch skeletal muscle fibers are often exposed to motor neuron double discharges (≥200 Hz), which markedly increase both the rate of contraction and the magnitude of the resulting force responses. However, the mechanism responsible for these effects is poorly understood, likely because of technical limitations in previous studies. In this study, we measured cytosolic Ca2+ during doublet activation using the low-affinity indicator Mag-Fluo-4 at high temporal resolution and modeled the effects of doublet stimulation on sarcoplasmic reticulum (SR) Ca2+ release, binding of Ca2+ to cytosolic buffers, and force enhancement in fast-twitch fibers. Single isolated fibers respond to doublet pulses with two clear Ca2+ spikes, at doublet frequencies up to 1 KHz. A 200-Hz doublet at the start of a tetanic stimulation train (70 Hz) decreases the drop in free Ca2+ between the first three Ca2+ spikes of the transient, maintaining a higher overall free Ca2+ level during first 20-30 ms of the response. Doublet stimulation also increased the rate of force development in isolated fast-twitch muscles. We also modeled SR Ca2+ release rates during doublet stimulation and showed that Ca2+-dependent inactivation of ryanodine receptor activity is rapid, occurring ≤1ms after initial release. Furthermore, we modeled Ca2+ binding to the main intracellular Ca2+ buffers of troponin C (TnC), parvalbumin, and the SR Ca2+ pump during Ca2+ release and found that the main effect of the second response in the doublet is to more rapidly increase the occupation of the second Ca2+-binding site on TnC (TnC2), resulting in earlier activation of force. We conclude that doublet stimulation maintains high cytosolic Ca2+ levels for longer in the early phase of the Ca2+ response, resulting in faster saturation of TnC2 with Ca2+, faster initiation of cross-bridge cycling, and more rapid force development.
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Affiliation(s)
- Anthony J Bakker
- School of Anatomy, Physiology, and Human Biology, University of Western Australia, Perth, WA 6009, Australia
| | - Tanya R Cully
- School of Biomedical Sciences, University of Queensland, Brisbane, QLD 4072, Australia
| | - Catherine D Wingate
- School of Anatomy, Physiology, and Human Biology, University of Western Australia, Perth, WA 6009, Australia
| | - Christopher J Barclay
- School of Allied Health Sciences, Griffith University, Gold Coast, QLD 4222, Australia
| | - Bradley S Launikonis
- School of Biomedical Sciences, University of Queensland, Brisbane, QLD 4072, Australia
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15
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Bhardwaj R, Hediger MA, Demaurex N. Redox modulation of STIM-ORAI signaling. Cell Calcium 2016; 60:142-52. [DOI: 10.1016/j.ceca.2016.03.006] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2016] [Accepted: 03/08/2016] [Indexed: 12/14/2022]
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16
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Cully TR, Edwards JN, Murphy RM, Launikonis BS. A quantitative description of tubular system Ca(2+) handling in fast- and slow-twitch muscle fibres. J Physiol 2016; 594:2795-810. [PMID: 26775687 DOI: 10.1113/jp271658] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2015] [Accepted: 12/28/2015] [Indexed: 01/26/2023] Open
Abstract
KEY POINTS Current methods do not allow a quantitative description of Ca(2+) movements across the tubular (t-) system membrane without isolating the membranes from their native skeletal muscle fibre. Here we present a fluorescence-based method that allows determination of the t-system [Ca(2+) ] transients and derivation of t-system Ca(2+) fluxes in mechanically skinned skeletal muscle fibres. Differences in t-system Ca(2+) -handling properties between fast- and slow-twitch fibres from rat muscle are resolved for the first time using this new technique. The method can be used to study Ca(2+) handling of the t-system and allows direct comparisons of t-system Ca(2+) transients and Ca(2+) fluxes between groups of fibres and fibres from different strains of animals. ABSTRACT The tubular (t-) system of skeletal muscle is an internalization of the plasma membrane that maintains a large Ca(2+) gradient and exchanges Ca(2+) between the extracellular and intracellular environments. Little is known of the Ca(2+) -handling properties of the t-system as the small Ca(2+) fluxes conducted are difficult to resolve with conventional methods. To advance knowledge in this area we calibrated t-system-trapped rhod-5N inside skinned fibres from rat and [Ca(2+) ]t-sys , allowing confocal measurements of Ca(2+) -dependent changes in rhod-5N fluorescence during rapid changes in the intracellular ionic environment to be converted to [Ca(2+) ] transients in the t-system ([Ca(2+) ]t-sys (t)). Furthermore, t-system Ca(2+) -buffering power was determined so that t-system Ca(2+) fluxes could be derived from [Ca(2+) ]t-sys (t). With this new approach, we show that rapid depletion of sarcoplasmic reticulum (SR) Ca(2+) induced a robust store-operated Ca(2+) entry (SOCE) in fast- and slow-twitch fibres, reducing [Ca(2+) ]t-sys to < 0.1 mm. The rapid activation of SOCE upon Ca(2+) release was consistent with the presence of STIM1L in both fibre types. Abruptly introducing internal solutions with 1 mm Mg(2+) and [Ca(2+) ]cyto (28 nm-1.3 μm) to Ca(2+) -depleted fibres generated t-system Ca(2+) uptake rates dependent on [Ca(2+) ]cyto with [Ca(2+) ]t-sys reaching final plateaus in the millimolar range. For the same [Ca(2+) ]cyto , t-system Ca(2+) fluxes of fast-twitch fibres were greater than that in slow-twitch fibres. In addition, simultaneous imaging of t-system and SR Ca(2+) signals indicated that both membrane compartments accumulated Ca(2+) at similar rates and that SOCE was activated early during SR Ca(2+) depletion.
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Affiliation(s)
- Tanya R Cully
- School of Biomedical Sciences, University of Queensland, Brisbane, QLD, 4072, Australia
| | - Joshua N Edwards
- School of Biomedical Sciences, University of Queensland, Brisbane, QLD, 4072, Australia
| | - Robyn M Murphy
- Department of Biochemistry and Genetics, La Trobe University, Melbourne, VIC, 3086, Australia
| | - Bradley S Launikonis
- School of Biomedical Sciences, University of Queensland, Brisbane, QLD, 4072, Australia
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17
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Cully TR, Launikonis BS. Leaky ryanodine receptors delay the activation of store overload-induced Ca2+ release, a mechanism underlying malignant hyperthermia-like events in dystrophic muscle. Am J Physiol Cell Physiol 2016; 310:C673-80. [PMID: 26825125 DOI: 10.1152/ajpcell.00366.2015] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2015] [Accepted: 01/19/2016] [Indexed: 02/04/2023]
Abstract
The mouse model of Duchenne muscular dystrophy, the mdx mouse, displays changes in Ca(2+)homeostasis that may lead to the pathology of the muscle. Here we examine the activation of store overload-induced Ca(2+)release (SOICR) in mdx muscle. The activation of SOICR is associated with the depolymerization of the sarcoplasmic reticulum (SR) Ca(2+)buffer calsequestrin and the reduction of SR Ca(2+)buffering power (BSR). The role of SOICR in healthy and dystrophic muscle is unclear. Using skinned fibers we show that lowering the Mg(2+)concentration can activate discrete Ca(2+)release events that did not necessarily lead to activation of SOICR. However, SOICR waves could propagate into these fiber segments. The average delay to activation of SOICR in mdx fibers was longer than in wild-type (WT) fibers. In the lowered Ca(2+)-buffered environment following large SOICR events, brief waves in mdx fibers displayed a low amplitude and propagation rate, in contrast to WT fibers that showed a range of amplitudes correlated with wave propagation rate. The distinct properties of SOICR in mdx fibers were consistent with a ryanodine receptor (RyR) that was leakier to Ca(2+)than in WT. The consequence of delayed SOICR and leaky RyRs is prolonged high BSRand a reduction in free Ca(2+)concentration inside the SR as total SR calcium drops. We present a hypothesis that SOICR activation is required in healthy muscle and that this mechanism works suboptimally in mdx fibers to fail to limit the activation of store-operated Ca(2+)entry.
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Affiliation(s)
- Tanya R Cully
- School of Biomedical Sciences, The University of Queensland, Brisbane, Queensland, Australia
| | - Bradley S Launikonis
- School of Biomedical Sciences, The University of Queensland, Brisbane, Queensland, Australia
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18
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Abstract
Store Operated Ca(2+) Entry (SOCE), the main Ca(2+) influx mechanism in non-excitable cells, is implicated in the immune response and has been reported to be affected in several pathologies including cancer. The basic molecular constituents of SOCE are Orai, the pore forming unit, and STIM, a multidomain protein with at least two principal functions: one is to sense the Ca(2+) content inside the lumen of the endoplasmic reticulum(ER) and the second is to activate Orai channels upon depletion of the ER. The link between Ca(2+) depletion inside the ER and Ca(2+) influx from extracellular media is through a direct association of STIM and Orai, but for this to occur, both molecules have to interact and form clusters where ER and plasma membrane (PM) are intimately apposed. In recent years a great number of components have been identified as participants in SOCE regulation, including regions of plasma membrane enriched in cholesterol and sphingolipids, the so called lipid rafts, which recruit a complex platform of specialized microdomains, which cells use to regulate spatiotemporal Ca(2+) signals.
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19
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Pászty K, Caride AJ, Bajzer Ž, Offord CP, Padányi R, Hegedűs L, Varga K, Strehler EE, Enyedi A. Plasma membrane Ca2+-ATPases can shape the pattern of Ca2+transients induced by store-operated Ca2+entry. Sci Signal 2015; 8:ra19. [DOI: 10.1126/scisignal.2005672] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
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20
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Goonasekera SA, Davis J, Kwong JQ, Accornero F, Wei-LaPierre L, Sargent MA, Dirksen RT, Molkentin JD. Enhanced Ca²⁺ influx from STIM1-Orai1 induces muscle pathology in mouse models of muscular dystrophy. Hum Mol Genet 2014; 23:3706-15. [PMID: 24556214 DOI: 10.1093/hmg/ddu079] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Muscular dystrophy is a progressive muscle wasting disease that is thought to be initiated by unregulated Ca(2+) influx into myofibers leading to their death. Store-operated Ca(2+) entry (SOCE) through sarcolemmal Ca(2+) selective Orai1 channels in complex with STIM1 in the sarcoplasmic reticulum is one such potential disease mechanism for pathologic Ca(2+) entry. Here, we generated a mouse model of STIM1 overexpression in skeletal muscle to determine whether this type of Ca(2+) entry could induce muscular dystrophy. Myofibers from muscle-specific STIM1 transgenic mice showed a significant increase in SOCE in skeletal muscle, modeling an observed increase in the same current in dystrophic myofibers. Histological and biochemical analysis of STIM1 transgenic mice showed fulminant muscle disease characterized by myofiber necrosis, swollen mitochondria, infiltration of inflammatory cells, enhanced interstitial fibrosis and elevated serum creatine kinase levels. This dystrophic-like disease in STIM1 transgenic mice was abrogated by crossing in a transgene expressing a dominant-negative Orai1 (dnOrai1) mutant. The dnOrai1 transgene also significantly reduced the severity of muscular dystrophy in both mdx (dystrophin mutant mice) and δ-sarcoglycan-deficient (Sgcd(-/-)) mouse models of disease. Hence, Ca(2+) influx across an unstable sarcolemma due to increased activity of a STIM1-Orai1 complex is a disease determinant in muscular dystrophy, and hence, SOCE represents a potential therapeutic target.
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Affiliation(s)
| | | | | | | | - Lan Wei-LaPierre
- Department of Pharmacology and Physiology, University of Rochester Medical Center, Rochester, NY, USA
| | | | - Robert T Dirksen
- Department of Pharmacology and Physiology, University of Rochester Medical Center, Rochester, NY, USA
| | - Jeffery D Molkentin
- Department of Pediatrics, University of Cincinnati and Howard Hughes Medical Institute, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA and
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21
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Posch A, Kohn J, Oh K, Hammond M, Liu N. V3 stain-free workflow for a practical, convenient, and reliable total protein loading control in western blotting. J Vis Exp 2013:50948. [PMID: 24429481 DOI: 10.3791/50948] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
The western blot is a very useful and widely adopted lab technique, but its execution is challenging. The workflow is often characterized as a "black box" because an experimentalist does not know if it has been performed successfully until the last of several steps. Moreover, the quality of western blot data is sometimes challenged due to a lack of effective quality control tools in place throughout the western blotting process. Here we describe the V3 western workflow, which applies stain-free technology to address the major concerns associated with the traditional western blot protocol. This workflow allows researchers: 1) to run a gel in about 20-30 min; 2) to visualize sample separation quality within 5 min after the gel run; 3) to transfer proteins in 3-10 min; 4) to verify transfer efficiency quantitatively; and most importantly 5) to validate changes in the level of the protein of interest using total protein loading control. This novel approach eliminates the need of stripping and reprobing the blot for housekeeping proteins such as β-actin, β-tubulin, GAPDH, etc. The V3 stain-free workflow makes the western blot process faster, transparent, more quantitative and reliable.
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22
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Cully TR, Launikonis BS. Store-operated Ca²⁺ entry is not required for store refilling in skeletal muscle. Clin Exp Pharmacol Physiol 2013; 40:338-44. [PMID: 23517302 DOI: 10.1111/1440-1681.12078] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2013] [Revised: 02/27/2013] [Accepted: 03/03/2013] [Indexed: 11/28/2022]
Abstract
The present review describes store-operated Ca²⁺ entry (SOCE) in skeletal muscle. Fundamental discoveries in the field of skeletal muscle SOCE are described and the techniques that were used to make these. The advantages and limitations in these techniques are discussed to provide a means of questioning and determining the physiological role(s) of SOCE in skeletal muscle. It is concluded that SOCE has little or no role in the filling of the sarcoplasmic reticulum with Ca²⁺ at rest or during a single contracture. It is likely that SOCE is activated during fatigue, although direct measurements of SOCE are lacking and the physiological significance remains uncertain.
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Affiliation(s)
- Tanya R Cully
- School of Biomedical Sciences, The University of Queensland, Brisbane, Qld, Australia
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