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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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Bolaños P, Calderón JC. Excitation-contraction coupling in mammalian skeletal muscle: Blending old and last-decade research. Front Physiol 2022; 13:989796. [PMID: 36117698 PMCID: PMC9478590 DOI: 10.3389/fphys.2022.989796] [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: 07/08/2022] [Accepted: 08/08/2022] [Indexed: 11/13/2022] Open
Abstract
The excitation–contraction coupling (ECC) in skeletal muscle refers to the Ca2+-mediated link between the membrane excitation and the mechanical contraction. The initiation and propagation of an action potential through the membranous system of the sarcolemma and the tubular network lead to the activation of the Ca2+-release units (CRU): tightly coupled dihydropyridine and ryanodine (RyR) receptors. The RyR gating allows a rapid, massive, and highly regulated release of Ca2+ from the sarcoplasmic reticulum (SR). The release from triadic places generates a sarcomeric gradient of Ca2+ concentrations ([Ca2+]) depending on the distance of a subcellular region from the CRU. Upon release, the diffusing Ca2+ has multiple fates: binds to troponin C thus activating the contractile machinery, binds to classical sarcoplasmic Ca2+ buffers such as parvalbumin, adenosine triphosphate and, experimentally, fluorescent dyes, enters the mitochondria and the SR, or is recycled through the Na+/Ca2+ exchanger and store-operated Ca2+ entry (SOCE) mechanisms. To commemorate the 7th decade after being coined, we comprehensively and critically reviewed “old”, historical landmarks and well-established concepts, and blended them with recent advances to have a complete, quantitative-focused landscape of the ECC. We discuss the: 1) elucidation of the CRU structures at near-atomic resolution and its implications for functional coupling; 2) reliable quantification of peak sarcoplasmic [Ca2+] using fast, low affinity Ca2+ dyes and the relative contributions of the Ca2+-binding mechanisms to the whole concert of Ca2+ fluxes inside the fibre; 3) articulation of this novel quantitative information with the unveiled structural details of the molecular machinery involved in mitochondrial Ca2+ handing to understand how and how much Ca2+ enters the mitochondria; 4) presence of the SOCE machinery and its different modes of activation, which awaits understanding of its magnitude and relevance in situ; 5) pharmacology of the ECC, and 6) emerging topics such as the use and potential applications of super-resolution and induced pluripotent stem cells (iPSC) in ECC. Blending the old with the new works better!
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Affiliation(s)
- Pura Bolaños
- Laboratory of Cellular Physiology, Centre of Biophysics and Biochemistry, Venezuelan Institute for Scientific Research (IVIC), Caracas, Venezuela
| | - Juan C. Calderón
- Physiology and Biochemistry Research Group-PHYSIS, Faculty of Medicine, University of Antioquia, Medellín, Colombia
- *Correspondence: Juan C. Calderón,
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3
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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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4
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Jayawardena TU, Kim SY, Jeon YJ. Sarcopenia; functional concerns, molecular mechanisms involved, and seafood as a nutritional intervention - review article. Crit Rev Food Sci Nutr 2021; 63:1983-2003. [PMID: 34459311 DOI: 10.1080/10408398.2021.1969889] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The fundamental basis for the human function is provided by skeletal muscle. Advancing age causes selective fiber atrophy, motor unit loss, and hybrid fiber formation resulting in hampered mass and strength, thus referred to as sarcopenia. Influence on the loss of independence of aged adults, contribute toward inclined healthcare costs conveys the injurious impact. The current understating of age-related skeletal muscle changes are addressed in this review, and further discusses mechanisms regulating protein turnover, although they do not completely define the process yet. Moreover, the reduced capacity of muscle regeneration due to impairment of satellite cell activation and proliferation with neuronal, immunological, hormonal factors were brought into the light of attention. Nevertheless, complete understating of sarcopenia requires disentangling it from disuse and disease. Nutritional intervention is considered a potentially preventable factor contributing to sarcopenia. Seafood is a crucial player in the fight against hunger and malnutrition, where it consists of macro and micronutrients. Hence, the review shed light on seafood as a nutritional intrusion in the treatment and prevention of sarcopenia. Understanding multiple factors will provide therapeutic targets in the prevention, treatment, and overcoming adverse effects of sarcopenia.
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Affiliation(s)
- Thilina U Jayawardena
- Department of Marine Life Sciences, Jeju National University, Jeju, Republic of Korea
| | - Seo-Young Kim
- Division of Practical Application, Honam National Institute of Biological Resources, Mokpo-si, Korea
| | - You-Jin Jeon
- Department of Marine Life Sciences, Jeju National University, Jeju, Republic of Korea.,Marine Science Institute, Jeju National University, Jeju, Jeju Self-Governing Province, Republic of Korea
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5
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Nagasaka T, Hata T, Shindo K, Adachi Y, Takeuchi M, Saito K, Takiyama Y. Morphological Alterations of the Sarcotubular System in Permanent Myopathy of Hereditary Hypokalemic Periodic Paralysis with a Mutation in the CACNA1S Gene. J Neuropathol Exp Neurol 2021; 79:1276-1292. [PMID: 33184660 DOI: 10.1093/jnen/nlaa098] [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] [Indexed: 01/10/2023] Open
Abstract
We investigated the immunohistochemical localization of several proteins related to excitation-contraction coupling and ultrastructural alterations of the sarcotubular system in biopsied muscles from a father and a daughter in a family with permanent myopathy with hypokalemic periodic paralysis (PMPP) due to a mutation in calcium channel CACNA1S; p. R1239H hetero. Immunostaining for L-type calcium channels (LCaC) showed linear hyper-stained regions indicating proliferation of longitudinal t-tubules. The margin of vacuoles was positive for ryanodine receptor, LCaC, calsequestrin (CASQ) 1, CASQ 2, SR/ER Ca2+-ATPase (SERCA) 1, SERCA2, dysferlin, dystrophin, α-actinin, LC3, and LAMP 1. Electron microscopy indicated that the vacuoles mainly originated from the sarcoplasmic reticulum (SR). These findings indicate impairment of the muscle contraction system related to Ca2+ dynamics, remodeling of t-tubules and muscle fiber repair. We speculate that PMPP in patients with a CACNA1S mutation might start with abnormal SR function due to impaired LCaC. Subsequent induction of muscular contractile abnormalities and the vacuoles formed by fused SR in the repair process including autophagy might result in permanent myopathy. Our findings may facilitate prediction of the pathomechanisms of PMPP seen on morphological observation.
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Affiliation(s)
- Takamura Nagasaka
- Department of Neurology, Faculty of Medicine, University of Yamanashi, Chuou-city, Yamanashi, Japan
| | - Takanori Hata
- Department of Neurology, Faculty of Medicine, University of Yamanashi, Chuou-city, Yamanashi, Japan
| | - Kazumasa Shindo
- Department of Neurology, Faculty of Medicine, University of Yamanashi, Chuou-city, Yamanashi, Japan
| | - Yoshiki Adachi
- Department of Neurology, Matsue Medical Center, National Hospital Organization, Shimane, Japan
| | | | - Kayoko Saito
- Institute of Medical Genetics, Tokyo Women's University, Tokyo, Japan
| | - Yoshihisa Takiyama
- Department of Neurology, Faculty of Medicine, University of Yamanashi, Chuou-city, Yamanashi, Japan
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6
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Rall JA. A perfect confluence of physiology and morphology: discovery of the transverse tubular system and inward spread of activation in skeletal muscle. ADVANCES IN PHYSIOLOGY EDUCATION 2020; 44:402-413. [PMID: 32697151 DOI: 10.1152/advan.00091.2020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
By early 1954, there existed a plausible model of muscle contraction called the sliding filament model. In addition, the nature of muscle excitation was understood. Surprisingly, the link between the membrane excitation and contraction was entirely unknown. This dilemma has been called the time-distance paradox. The path to discovery of the missing link between excitation and contraction was a rocky one involving the simultaneous but independent development of physiological and morphological studies. From the viewpoint of physiology, significant events included the most thrilling moment of a scientific life, confirmation of a hypothesis that was wrong, a major surprise and shock, a result not expected from evolutionary relationships, and disappointment and confusion before clarity. From the viewpoint of morphology, there was the exciting beginning and rapid development of biological electron microscopy, heroic experiments, the importance of sample preparative procedures, and discovery of clues from the old light microscopic literature. However, it was the confluence of physiology and morphology that brought clarity and a major advance in understanding, leading to the discovery of the transverse tubular system and inward spread of activation in skeletal muscle.
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Affiliation(s)
- Jack A Rall
- Department of Physiology and Cell Biology, College of Medicine, Ohio State University, Columbus, Ohio
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7
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Hall TE, Martel N, Ariotti N, Xiong Z, Lo HP, Ferguson C, Rae J, Lim YW, Parton RG. In vivo cell biological screening identifies an endocytic capture mechanism for T-tubule formation. Nat Commun 2020; 11:3711. [PMID: 32709891 PMCID: PMC7381618 DOI: 10.1038/s41467-020-17486-w] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2017] [Accepted: 06/26/2020] [Indexed: 11/09/2022] Open
Abstract
The skeletal muscle T-tubule is a specialized membrane domain essential for coordinated muscle contraction. However, in the absence of genetically tractable systems the mechanisms involved in T-tubule formation are unknown. Here, we use the optically transparent and genetically tractable zebrafish system to probe T-tubule development in vivo. By combining live imaging of transgenic markers with three-dimensional electron microscopy, we derive a four-dimensional quantitative model for T-tubule formation. To elucidate the mechanisms involved in T-tubule formation in vivo, we develop a quantitative screen for proteins that associate with and modulate early T-tubule formation, including an overexpression screen of the entire zebrafish Rab protein family. We propose an endocytic capture model involving firstly, formation of dynamic endocytic tubules at transient nucleation sites on the sarcolemma, secondly, stabilization by myofibrils/sarcoplasmic reticulum and finally, delivery of membrane from the recycling endosome and Golgi complex.
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Affiliation(s)
- Thomas E Hall
- Institute for Molecular Bioscience, University of Queensland, Brisbane, QLD, 4072, Australia.
| | - Nick Martel
- Institute for Molecular Bioscience, University of Queensland, Brisbane, QLD, 4072, Australia
| | - Nicholas Ariotti
- Institute for Molecular Bioscience, University of Queensland, Brisbane, QLD, 4072, Australia.,Electron Microscope Unit, Mark Wainwright Analytical Centre, The University of New South Wales, Kensington, Australia
| | - Zherui Xiong
- Institute for Molecular Bioscience, University of Queensland, Brisbane, QLD, 4072, Australia
| | - Harriet P Lo
- Institute for Molecular Bioscience, University of Queensland, Brisbane, QLD, 4072, Australia
| | - Charles Ferguson
- Institute for Molecular Bioscience, University of Queensland, Brisbane, QLD, 4072, Australia
| | - James Rae
- Institute for Molecular Bioscience, University of Queensland, Brisbane, QLD, 4072, Australia
| | - Ye-Wheen Lim
- Institute for Molecular Bioscience, University of Queensland, Brisbane, QLD, 4072, Australia
| | - Robert G Parton
- Institute for Molecular Bioscience, University of Queensland, Brisbane, QLD, 4072, Australia. .,Centre for Microscopy and Microanalysis, University of Queensland, Brisbane, QLD, 4072, Australia.
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8
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Huerlimann R, Maes GE, Maxwell MJ, Mobli M, Launikonis BS, Jerry DR, Wade NM. Multi-species transcriptomics reveals evolutionary diversity in the mechanisms regulating shrimp tail muscle excitation-contraction coupling. Gene 2020; 752:144765. [PMID: 32413480 DOI: 10.1016/j.gene.2020.144765] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2020] [Revised: 04/17/2020] [Accepted: 05/11/2020] [Indexed: 11/30/2022]
Abstract
The natural flight response in shrimp is powered by rapid contractions of the abdominal muscle fibres to propel themselves backwards away from perceived danger. This muscle contraction is dependent on repetitive depolarization of muscle plasma membrane, triggering tightly spaced cytoplasmic [Ca2+] transients and rapidly rising tetanic force responses. To achieve such high amplitude and high frequency of Ca2+ transients requires a high abundance of sarcoplasmic/endoplasmic reticulum Ca2+ ATPase (SERCA) to rapidly clear cytoplasmic Ca2+ between each transient and an efficient Ca2+ release system consisting of the Ryanodine Receptor (RyR), and voltage gated Ca2+ channels (CaVs). With the aim to expand our knowledge of muscle gene function and identify orthologous genes regulating muscle excitation-contraction (EC) coupling, this study assembled nine Penaeid shrimp muscle transcriptomes. On average, the nine transcriptomes contained 27,000 contigs, with an annotation rate of 36% and a BUSCO completeness of 70%. Despite maintaining their function, the crustacean RyR and CaV proteins showed evidence of significant diversification from mammalian orthologs, while SERCA remained more conserved. Several key components of protein interaction were conserved, while others showed distinct crustacean specific evolutionary adaptations. Lastly, this study revealed approximately 1,000 orthologous genes involved in muscle specific processes present across all nine species.
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Affiliation(s)
- Roger Huerlimann
- ARC Research Hub for Advanced Prawn Breeding, Australia; Centre for Sustainable Tropical Fisheries and Aquaculture, College of Science and Engineering, James Cook University, Townsville, QLD 4811, Australia; Centre for Tropical Bioinformatics and Molecular Biology, James Cook University, Townsville, QLD 4811, Australia.
| | - Gregory E Maes
- Centre for Sustainable Tropical Fisheries and Aquaculture, College of Science and Engineering, James Cook University, Townsville, QLD 4811, Australia; Laboratory of Biodiversity and Evolutionary Genomics, KU Leuven, Leuven 3000, Belgium; Centre for Human Genetics, KU Leuven, Leuven 3000, Belgium
| | - Michael J Maxwell
- Centre for Advanced Imaging, University of Queensland, Brisbane, QLD 4072, Australia
| | - Mehdi Mobli
- Centre for Advanced Imaging, University of Queensland, Brisbane, QLD 4072, Australia
| | - Bradley S Launikonis
- School of Biomedical Sciences, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Dean R Jerry
- ARC Research Hub for Advanced Prawn Breeding, Australia; Centre for Sustainable Tropical Fisheries and Aquaculture, College of Science and Engineering, James Cook University, Townsville, QLD 4811, Australia; Tropical Futures Institute, James Cook University, 149 Sims Drive, Singapore 387380, Singapore
| | - Nicholas M Wade
- ARC Research Hub for Advanced Prawn Breeding, Australia; CSIRO Agriculture and Food, Aquaculture Program, 306 Carmody Road, St Lucia, QLD 4067
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9
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Ren X, Lamb GD, Murphy RM. Distribution and activation of matrix metalloproteinase-2 in skeletal muscle fibers. Am J Physiol Cell Physiol 2019; 317:C613-C625. [PMID: 31241984 DOI: 10.1152/ajpcell.00113.2019] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
A substantial intracellular localization of matrix metalloproteinase 2 (MMP2) has been reported in cardiomyocytes, where it plays a role in the degradation of the contractile apparatus following ischemia-reperfusion injury. Whether MMP2 may have a similar function in skeletal muscle is unknown. This study determined that the absolute amount of MMP2 is similar in rat skeletal and cardiac muscle and human muscle (~10-18 nmol/kg muscle wet wt) but is ~50- to 100-fold less than the amount of calpain-1. We compared mechanically skinned muscle fibers, where the extracellular matrix (ECM) is completely removed, with intact fiber segments and found that ~30% of total MMP2 was associated with the ECM, whereas ~70% was inside the muscle fibers. Concordant with whole muscle fractionation, further separation of skinned fiber segments into cytosolic, membranous, and cytoskeletal and nuclear compartments indicated that ~57% of the intracellular MMP2 was freely diffusible, ~6% was associated with the membrane, and ~37% was bound within the fiber. Under native zymography conditions, only 10% of MMP2 became active upon prolonged (17 h) exposure to 20 μM Ca2+, a concentration that would fully activate calpain-1 in seconds to minutes; full activation of MMP2 would require ~1 mM Ca2+. Given the prevalence of intracellular MMP2 in skeletal muscle, it is necessary to investigate its function using physiological conditions, including isolation of any potential functional relevance of MMP2 from that of the abundant protease calpain-1.
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Affiliation(s)
- Xiaoyu Ren
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, Victoria, Australia
| | - Graham D Lamb
- School of Life Sciences, La Trobe University, Melbourne, Victoria, Australia
| | - Robyn M Murphy
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, Victoria, Australia
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10
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Rusu MC, Nicolescu MI, Jianu AM, Mănoiu VS, Ilie AC, Dincă D. The ultrastructural anatomy of the nuclear envelope in the masseter muscle indicates its role in the metabolism of the intracellular Ca +. Ann Anat 2019; 224:117-123. [PMID: 31117003 DOI: 10.1016/j.aanat.2019.05.006] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2018] [Revised: 04/05/2019] [Accepted: 05/06/2019] [Indexed: 11/16/2022]
Abstract
Specific ultrastructural anatomy of masticatory muscles is commonly referred to a general pattern assigned to striated muscles. Junctional feet consisting of calcium channels of the sarcoplasmic reticulum (i.e. the ryanodine receptors, RyRs) physically connected to the calcium channels of the t-tubules build triads within striated muscles. Functional RyRs were demonstrated in the nuclear envelopes of pancreas and of a skeletal muscle derived cell line, but not in muscle in situ. It was hypothesized that ryanodine receptors (RyRs) could also exist in the nuclear envelope in the masseter muscle, thus aiming at studying this by transmission electron microscopy. There were identified paired and consistent subsarcolemmal clusters of mitochondria, appearing as outpockets of the muscle fibers, usually flanking an endomysial microvessel. It was observed on grazing longitudinal cuts that the I-band-limited mitochondria were not strictly located in a single intermyofibrillar space but continued transversally over the I-band to the next intermyofibrillar space. It appeared that the I-band-limited transverse mitochondria participate with the column-forming mitochondria in building a rather incomplete mitochondrial reticulum of the masseter muscle. Subsarcolemmal nuclei presented nuclear envelope-associated RyRs. Moreover, t-tubules were contacting the nuclear envelope and they were seemingly filled from the perinuclear space. This could suggest that nucleoplasmic calcium could contribute to balance the cytosolic concentration via pre-built anatomical routes: (i) indirectly, via the RyRs of the nuclear envelope and (ii) directly via the communication of t-tubules and sarcoplasmic reticulum through the perinuclear space.
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Affiliation(s)
- M C Rusu
- Division of Anatomy, Faculty of Dental Medicine, "Carol Davila" University of Medicine and Pharmacy, Bucharest, Romania.
| | - M I Nicolescu
- Division of Histology, Faculty of Dental Medicine, "Carol Davila" University of Medicine and Pharmacy, Bucharest, Romania; "Victor Babeș" National Institute of Pathology, Bucharest, Romania
| | - A M Jianu
- Division of Anatomy, Faculty of Medicine, "Victor Babeş" University of Medicine and Pharmacy, Timişoara, Romania
| | - V S Mănoiu
- Department of Cellular and Molecular Biology, National Institute of Research and Development for Biological Sciences, Bucharest, Romania
| | - A C Ilie
- Division of Anatomy, Faculty of Medicine, "Victor Babeş" University of Medicine and Pharmacy, Timişoara, Romania
| | - D Dincă
- Department II of Surgical Clinical Divisions, Faculty of Medicine, "Ovidius" University, Constanţa, Romania
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11
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Franzini-Armstrong C. The relationship between form and function throughout the history of excitation-contraction coupling. J Gen Physiol 2018; 150:189-210. [PMID: 29317466 PMCID: PMC5806676 DOI: 10.1085/jgp.201711889] [Citation(s) in RCA: 46] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Franzini-Armstrong reviews the development of the excitation–contraction coupling field over time. The concept of excitation–contraction coupling is almost as old as Journal of General Physiology. It was understood as early as the 1940s that a series of stereotyped events is responsible for the rapid contraction response of muscle fibers to an initial electrical event at the surface. These early developments, now lost in what seems to be the far past for most young investigators, have provided an endless source of experimental approaches. In this Milestone in Physiology, I describe in detail the experiments and concepts that introduced and established the field of excitation–contraction coupling in skeletal muscle. More recent advances are presented in an abbreviated form, as readers are likely to be familiar with recent work in the field.
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Affiliation(s)
- Clara Franzini-Armstrong
- Department of Cell and Developmental Biology, University of Pennsylvania School of Medicine, Philadelphia, PA
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12
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Cully TR, Murphy RM, Roberts L, Raastad T, Fassett RG, Coombes JS, Jayasinghe I, Launikonis BS. Human skeletal muscle plasmalemma alters its structure to change its Ca 2+-handling following heavy-load resistance exercise. Nat Commun 2017; 8:14266. [PMID: 28193999 PMCID: PMC5316829 DOI: 10.1038/ncomms14266] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2016] [Accepted: 12/08/2016] [Indexed: 01/30/2023] Open
Abstract
High-force eccentric exercise results in sustained increases in cytoplasmic Ca2+ levels ([Ca2+]cyto), which can cause damage to the muscle. Here we report that a heavy-load strength training bout greatly alters the structure of the membrane network inside the fibres, the tubular (t-) system, causing the loss of its predominantly transverse organization and an increase in vacuolation of its longitudinal tubules across adjacent sarcomeres. The transverse tubules and vacuoles displayed distinct Ca2+-handling properties. Both t-system components could take up Ca2+ from the cytoplasm but only transverse tubules supported store-operated Ca2+ entry. The retention of significant amounts of Ca2+ within vacuoles provides an effective mechanism to reduce the total content of Ca2+ within the fibre cytoplasm. We propose this ability can reduce or limit resistance exercise-induced, Ca2+-dependent damage to the fibre by the reduction of [Ca2+]cyto to help maintain fibre viability during the period associated with delayed onset muscle soreness.
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Affiliation(s)
- Tanya R. Cully
- School of Biomedical Sciences, The University of Queensland,
Brisbane, Queensland
4072, Australia
| | - Robyn M. Murphy
- Department of Biochemistry & Genetics, La Trobe Institute for
Molecular Science, La Trobe University, Melbourne, Victoria
3086, Australia
| | - Llion Roberts
- School of Human Movement and Nutritional Sciences, The University of
Queensland, Brisbane, Queensland
4072, Australia
- Centre of Excellence for Applied Sport Science Research, Queensland
Academy of Sport, Brisbane, Queensland
4111, Australia
| | - Truls Raastad
- Norwegian School of Sport Sciences, Oslo
N-0806, Norway
| | - Robert G. Fassett
- School of Human Movement and Nutritional Sciences, The University of
Queensland, Brisbane, Queensland
4072, Australia
| | - Jeff S. Coombes
- School of Human Movement and Nutritional Sciences, The University of
Queensland, Brisbane, Queensland
4072, Australia
| | - Izzy Jayasinghe
- School of Biomedical Sciences, The University of Queensland,
Brisbane, Queensland
4072, Australia
- School of Biomedical Sciences, University of Leeds,
Leeds
LS2 9JT, UK
| | - Bradley S. Launikonis
- School of Biomedical Sciences, The University of Queensland,
Brisbane, Queensland
4072, Australia
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13
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Mayfield DL, Launikonis BS, Cresswell AG, Lichtwark GA. Additional in-series compliance reduces muscle force summation and alters the time course of force relaxation during fixed-end contractions. ACTA ACUST UNITED AC 2016; 219:3587-3596. [PMID: 27609762 DOI: 10.1242/jeb.143123] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2016] [Accepted: 08/31/2016] [Indexed: 02/06/2023]
Abstract
There are high mechanical demands placed on skeletal muscles in movements requiring rapid acceleration of the body or its limbs. Tendons are responsible for transmitting muscle forces, but, because of their elasticity, can manipulate the mechanics of the internal contractile apparatus. Shortening of the contractile apparatus against the stretch of tendon affects force generation according to known mechanical properties; however, the extent to which differences in tendon compliance alter force development in response to a burst of electrical impulses is unclear. To establish the influence of series compliance on force summation, we studied electrically evoked doublet contractions in the cane toad peroneus muscle in the presence and absence of a compliant artificial tendon. Additional series compliance reduced tetanic force by two-thirds, a finding predicted based on the force-length property of skeletal muscle. Doublet force and force-time integral expressed relative to the twitch were also reduced by additional series compliance. Active shortening over a larger range of the ascending limb of the force-length curve and at a higher velocity, leading to a progressive reduction in force-generating potential, could be responsible. Muscle-tendon interaction may also explain the accelerated time course of force relaxation in the presence of additional compliance. Our findings suggest that a compliant tendon limits force summation under constant-length conditions. However, high series compliance can be mechanically advantageous when a muscle-tendon unit is actively stretched, permitting muscle fibres to generate force almost isometrically, as shown during stretch-shorten cycles in locomotor activities. Restricting active shortening would likely favour rapid force development.
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Affiliation(s)
- Dean L Mayfield
- Centre for Sensorimotor Performance, School of Human Movement and Nutrition Sciences, The University of Queensland, Brisbane, Queensland 4072, Australia
| | | | - Andrew G Cresswell
- Centre for Sensorimotor Performance, School of Human Movement and Nutrition Sciences, The University of Queensland, Brisbane, Queensland 4072, Australia
| | - Glen A Lichtwark
- Centre for Sensorimotor Performance, School of Human Movement and Nutrition Sciences, The University of Queensland, Brisbane, Queensland 4072, Australia
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15
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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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16
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Georgiev T, Zapiec B, Förderer M, Fink RHA, Vogel M. Colocalization properties of elementary Ca(2+) release signals with structures specific to the contractile filaments and the tubular system of intact mouse skeletal muscle fibers. J Struct Biol 2015; 192:366-375. [PMID: 26431893 DOI: 10.1016/j.jsb.2015.09.018] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2015] [Revised: 09/26/2015] [Accepted: 09/29/2015] [Indexed: 11/19/2022]
Abstract
Ca(2+) regulates several important intracellular processes. We combined second harmonic generation (SHG) and two photon excited fluorescence microscopy (2PFM) to simultaneously record the SHG signal of the myosin filaments and localized elementary Ca(2+) release signals (LCSs). We found LCSs associated with Y-shaped structures of the myosin filament pattern (YMs), so called verniers, in intact mouse skeletal muscle fibers under hypertonic treatment. Ion channels crucial for the Ca(2+) regulation are located in the tubular system, a system that is important for Ca(2+) regulation and excitation-contraction coupling. We investigated the tubular system of intact, living mouse skeletal muscle fibers using 2PFM and the fluorescent Ca(2+) indicator Fluo-4 dissolved in the external solution or the membrane dye di-8-ANEPPS. We simultaneously measured the SHG signal from the myosin filaments of the skeletal muscle fibers. We found that at least a subset of the YMs observed in SHG images are closely juxtaposed with Y-shaped structures of the transverse tubules (YTs). The distances of corresponding YMs and YTs yield values between 1.3 μm and 4.1 μm including pixel uncertainty with a mean distance of 2.52±0.10 μm (S.E.M., n=41). Additionally, we observed that some of the linear-shaped areas in the tubular system are colocalized with linear-shaped areas in the SHG images.
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Affiliation(s)
- Tihomir Georgiev
- Medical Biophysics, Institute of Physiology and Pathophysiology, Ruprecht Karls Universität, Im Neuenheimer Feld 326, 69120 Heidelberg, Germany.
| | - Bolek Zapiec
- Medical Biophysics, Institute of Physiology and Pathophysiology, Ruprecht Karls Universität, Im Neuenheimer Feld 326, 69120 Heidelberg, Germany; Max Planck Research Unit for Neurogenetics, 60438 Frankfurt am Main, Germany
| | - Moritz Förderer
- Medical Biophysics, Institute of Physiology and Pathophysiology, Ruprecht Karls Universität, Im Neuenheimer Feld 326, 69120 Heidelberg, Germany
| | - Rainer H A Fink
- Medical Biophysics, Institute of Physiology and Pathophysiology, Ruprecht Karls Universität, Im Neuenheimer Feld 326, 69120 Heidelberg, Germany
| | - Martin Vogel
- Medical Biophysics, Institute of Physiology and Pathophysiology, Ruprecht Karls Universität, Im Neuenheimer Feld 326, 69120 Heidelberg, Germany; Max Planck Research Unit for Neurogenetics, 60438 Frankfurt am Main, Germany.
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Georgiev T, Svirin M, Jaimovich E, Fink RHA. Localized nuclear and perinuclear Ca(2+) signals in intact mouse skeletal muscle fibers. Front Physiol 2015; 6:263. [PMID: 26483696 PMCID: PMC4586431 DOI: 10.3389/fphys.2015.00263] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2015] [Accepted: 09/07/2015] [Indexed: 11/13/2022] Open
Abstract
Nuclear Ca2+ is important for the regulation of several nuclear processes such as gene expression. Localized Ca2+ signals (LCSs) in skeletal muscle fibers of mice have been mainly studied as Ca2+ release events from the sarcoplasmic reticulum. Their location with regard to cell nuclei has not been investigated. Our study is based on the hypothesis that LCSs associated with nuclei are present in skeletal muscle fibers of adult mice. Therefore, we carried out experiments addressing this question and we found novel Ca2+ signals associated with nuclei of skeletal muscle fibers (with possibly attached satellite cells). We measured localized nuclear and perinuclear Ca2+ signals (NLCSs and PLCSs) alongside cytosolic localized Ca2+ signals (CLCSs) during a hypertonic treatment. We also observed NLCSs under isotonic conditions. The NLCSs and PLCSs are Ca2+ signals in the range of micrometer [FWHM (full width at half maximum): 2.75 ± 0.27 μm (NLCSs) and 2.55 ± 0.17 μm (PLCSs), S.E.M.]. Additionally, global nuclear Ca2+ signals (NGCSs) were observed. To investigate which type of Ca2+ channels contribute to the Ca2+ signals associated with nuclei in skeletal muscle fibers, we performed measurements with the RyR blocker dantrolene, the DHPR blocker nifedipine or the IP3R blocker Xestospongin C. We observed Ca2+ signals associated with nuclei in the presence of each blocker. Nifedipine and dantrolene had an inhibitory effect on the fraction of fibers with PLCSs. The situation for the fraction of fibers with NLCSs is more complex indicating that RyR is less important for the generation of NLCSs compared to the generation of PLCSs. The fraction of fibers with NLCSs and PLCSs is not reduced in the presence of Xestospongin C. The localized perinuclear and intranuclear Ca2+ signals may be a powerful tool for the cell to regulate adaptive processes as gene expression. The intranuclear Ca2+ signals may be particularly interesting in this respect.
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Affiliation(s)
- Tihomir Georgiev
- Medical Biophysics Unit, Institut für Physiologie und Pathophysiologie, Ruprecht Karls Universität Heidelberg, Germany ; Facultad de Medicina, Center for Molecular Studies of the Cell, Universidad de Chile Santiago de Chile, Chile
| | - Mikhail Svirin
- Medical Biophysics Unit, Institut für Physiologie und Pathophysiologie, Ruprecht Karls Universität Heidelberg, Germany
| | - Enrique Jaimovich
- Facultad de Medicina, Center for Molecular Studies of the Cell, Universidad de Chile Santiago de Chile, Chile
| | - Rainer H A Fink
- Medical Biophysics Unit, Institut für Physiologie und Pathophysiologie, Ruprecht Karls Universität Heidelberg, Germany
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18
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Demonbreun AR, Swanson KE, Rossi AE, Deveaux HK, Earley JU, Allen MV, Arya P, Bhattacharyya S, Band H, Pytel P, McNally EM. Eps 15 Homology Domain (EHD)-1 Remodels Transverse Tubules in Skeletal Muscle. PLoS One 2015; 10:e0136679. [PMID: 26325203 PMCID: PMC4556691 DOI: 10.1371/journal.pone.0136679] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2015] [Accepted: 08/06/2015] [Indexed: 11/19/2022] Open
Abstract
We previously showed that Eps15 homology domain-containing 1 (EHD1) interacts with ferlin proteins to regulate endocytic recycling. Myoblasts from Ehd1-null mice were found to have defective recycling, myoblast fusion, and consequently smaller muscles. When expressed in C2C12 cells, an ATPase dead-EHD1 was found to interfere with BIN1/amphiphysin 2. We now extended those findings by examining Ehd1-heterozygous mice since these mice survive to maturity in normal Mendelian numbers and provide a ready source of mature muscle. We found that heterozygosity of EHD1 was sufficient to produce ectopic and excessive T-tubules, including large intracellular aggregates that contained BIN1. The disorganized T-tubule structures in Ehd1-heterozygous muscle were accompanied by marked elevation of the T-tubule-associated protein DHPR and reduction of the triad linker protein junctophilin 2, reflecting defective triads. Consistent with this, Ehd1-heterozygous muscle had reduced force production. Introduction of ATPase dead-EHD1 into mature muscle fibers was sufficient to induce ectopic T-tubule formation, seen as large BIN1 positive structures throughout the muscle. Ehd1-heterozygous mice were found to have strikingly elevated serum creatine kinase and smaller myofibers, but did not display findings of muscular dystrophy. These data indicate that EHD1 regulates the maintenance of T-tubules through its interaction with BIN1 and links T-tubules defects with elevated creatine kinase and myopathy.
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Affiliation(s)
- Alexis R. Demonbreun
- Center for Genetic Medicine, Northwestern University, Chicago, IL, United States of America
- * E-mail:
| | - Kaitlin E. Swanson
- Department of Pathology, The University of Chicago, Chicago, IL, United States of America
| | - Ann E. Rossi
- Department of Medicine, The University of Chicago, Chicago, IL, United States of America
| | - H. Kieran Deveaux
- Department of Medicine, The University of Chicago, Chicago, IL, United States of America
| | - Judy U. Earley
- Center for Genetic Medicine, Northwestern University, Chicago, IL, United States of America
| | - Madison V. Allen
- Center for Genetic Medicine, Northwestern University, Chicago, IL, United States of America
| | - Priyanka Arya
- Department of Genetics, Cell Biology & Anatomy, University of Nebraska Medical Center, Omaha, NE, United States of America
| | - Sohinee Bhattacharyya
- Department of Pathology & Microbiology, Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center, Omaha, NE, United States of America
| | - Hamid Band
- Department of Pathology & Microbiology, Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center, Omaha, NE, United States of America
| | - Peter Pytel
- Department of Pathology, The University of Chicago, Chicago, IL, United States of America
| | - Elizabeth M. McNally
- Center for Genetic Medicine, Northwestern University, Chicago, IL, United States of America
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19
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Barrientos G, Llanos P, Hidalgo J, Bolaños P, Caputo C, Riquelme A, Sánchez G, Quest AFG, Hidalgo C. Cholesterol removal from adult skeletal muscle impairs excitation-contraction coupling and aging reduces caveolin-3 and alters the expression of other triadic proteins. Front Physiol 2015; 6:105. [PMID: 25914646 PMCID: PMC4392612 DOI: 10.3389/fphys.2015.00105] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2015] [Accepted: 03/16/2015] [Indexed: 12/30/2022] Open
Abstract
Cholesterol and caveolin are integral membrane components that modulate the function/location of many cellular proteins. Skeletal muscle fibers, which have unusually high cholesterol levels in transverse tubules, express the caveolin-3 isoform but its association with transverse tubules remains contentious. Cholesterol removal impairs excitation–contraction (E–C) coupling in amphibian and mammalian fetal skeletal muscle fibers. Here, we show that treating single muscle fibers from adult mice with the cholesterol removing agent methyl-β-cyclodextrin decreased fiber cholesterol by 26%, altered the location pattern of caveolin-3 and of the voltage dependent calcium channel Cav1.1, and suppressed or reduced electrically evoked Ca2+ transients without affecting membrane integrity or causing sarcoplasmic reticulum (SR) calcium depletion. We found that transverse tubules from adult muscle and triad fractions that contain ~10% attached transverse tubules, but not SR membranes, contained caveolin-3 and Cav1.1; both proteins partitioned into detergent-resistant membrane fractions highly enriched in cholesterol. Aging entails significant deterioration of skeletal muscle function. We found that triad fractions from aged rats had similar cholesterol and RyR1 protein levels compared to triads from young rats, but had lower caveolin-3 and glyceraldehyde 3-phosphate dehydrogenase and increased Na+/K+-ATPase protein levels. Both triad fractions had comparable NADPH oxidase (NOX) activity and protein content of NOX2 subunits (p47phox and gp91phox), implying that NOX activity does not increase during aging. These findings show that partial cholesterol removal impairs E–C coupling and alters caveolin-3 and Cav1.1 location pattern, and that aging reduces caveolin-3 protein content and modifies the expression of other triadic proteins. We discuss the possible implications of these findings for skeletal muscle function in young and aged animals.
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Affiliation(s)
- Genaro Barrientos
- Physiology and Biophysics Program, Institute of Biomedical Sciences, School of Medicine, University of Chile Santiago, Chile
| | - Paola Llanos
- Institute for Research in Dental Sciences, Faculty of Dentistry, University of Chile Santiago, Chile
| | - Jorge Hidalgo
- Physiology and Biophysics Program, Institute of Biomedical Sciences, School of Medicine, University of Chile Santiago, Chile
| | - Pura Bolaños
- Centre of Biophysics and Biochemistry, Venezuelan Institute for Scientific Research Caracas, Venezuela
| | - Carlo Caputo
- Centre of Biophysics and Biochemistry, Venezuelan Institute for Scientific Research Caracas, Venezuela
| | - Alexander Riquelme
- Biomedical Neuroscience Institute, School of Medicine, University of Chile Santiago, Chile
| | - Gina Sánchez
- Biomedical Neuroscience Institute, School of Medicine, University of Chile Santiago, Chile ; Pathophysiology Program, Institute of Biomedical Sciences, School of Medicine, University of Chile Santiago, Chile ; Center for Molecular Studies of the Cell, School of Medicine, University of Chile Santiago, Chile
| | - Andrew F G Quest
- Center for Molecular Studies of the Cell, School of Medicine, University of Chile Santiago, Chile ; Laboratory of Cell Communication, Program in Cell and Molecular Biology, Institute of Biomedical Sciences, School of Medicine, University of Chile Santiago, Chile ; Advanced Center for Chronic Diseases and Network for Metabolic Stress Signaling, University of Chile Santiago, Chile
| | - Cecilia Hidalgo
- Physiology and Biophysics Program, Institute of Biomedical Sciences, School of Medicine, University of Chile Santiago, Chile ; Biomedical Neuroscience Institute, School of Medicine, University of Chile Santiago, Chile ; Center for Molecular Studies of the Cell, School of Medicine, University of Chile Santiago, Chile
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20
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Recher G, Coumailleau P, Rouède D, Tiaho F. Structural origin of the drastic modification of second harmonic generation intensity pattern occurring in tail muscles of climax stages xenopus tadpoles. J Struct Biol 2015; 190:1-10. [PMID: 25770062 DOI: 10.1016/j.jsb.2015.03.003] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2014] [Revised: 02/08/2015] [Accepted: 03/04/2015] [Indexed: 01/27/2023]
Abstract
Second harmonic generation (SHG) microscopy is a powerful tool for studying submicron architecture of muscles tissues. Using this technique, we show that the canonical single frequency sarcomeric SHG intensity pattern (SHG-IP) of premetamorphic xenopus tadpole tail muscles is converted to double frequency (2f) sarcomeric SHG-IP in metamorphic climax stages due to massive physiological muscle proteolysis. This conversion was found to rise from 7% in premetamorphic muscles to about 97% in fragmented muscular apoptotic bodies. Moreover a 66% conversion was also found in non-fragmented metamorphic tail muscles. Also, a strong correlation between predominant 2f sarcomeric SHG-IPs and myofibrillar misalignment is established with electron microscopy. Experimental and theoretical results demonstrate the higher sensitivity and the supra resolution power of SHG microscopy over TPEF to reveal 3D myofibrillar misalignment. From this study, we suggest that 2f sarcomeric SHG-IP could be used as signature of triad defect and disruption of excitation-contraction coupling. As the mechanism of muscle proteolysis is similar to that found in mdx mouse muscles, we further suggest that xenopus tadpole tail resorption at climax stages could be used as an alternative or complementary model of Duchene muscular dystrophy.
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Affiliation(s)
- Gaëlle Recher
- UMR CNRS 6026, Université de Rennes1, Campus de Beaulieu, Rennes F-35000, France; Department of Physiology, Development and Neuroscience, University of Cambridge, Downing Street, Cambridge CB2 3DY, UK
| | - Pascal Coumailleau
- UMR CNRS 6026, Université de Rennes1, Campus de Beaulieu, Rennes F-35000, France; IRSET, INSERM, U1085, Université de Rennes1, Campus de Beaulieu, Rennes F-35000, France
| | - Denis Rouède
- IPR, CNRS, UMR-CNRS UR1-6251, Université de Rennes1, Campus de Beaulieu, Rennes F-35000, France
| | - François Tiaho
- UMR CNRS 6026, Université de Rennes1, Campus de Beaulieu, Rennes F-35000, France; IRSET, INSERM, U1085, Université de Rennes1, Campus de Beaulieu, Rennes F-35000, France.
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21
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Frontera WR, Ochala J. Skeletal muscle: a brief review of structure and function. Calcif Tissue Int 2015; 96:183-95. [PMID: 25294644 DOI: 10.1007/s00223-014-9915-y] [Citation(s) in RCA: 758] [Impact Index Per Article: 84.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/09/2014] [Accepted: 09/16/2014] [Indexed: 01/23/2023]
Abstract
Skeletal muscle is one of the most dynamic and plastic tissues of the human body. In humans, skeletal muscle comprises approximately 40% of total body weight and contains 50-75% of all body proteins. In general, muscle mass depends on the balance between protein synthesis and degradation and both processes are sensitive to factors such as nutritional status, hormonal balance, physical activity/exercise, and injury or disease, among others. In this review, we discuss the various domains of muscle structure and function including its cytoskeletal architecture, excitation-contraction coupling, energy metabolism, and force and power generation. We will limit the discussion to human skeletal muscle and emphasize recent scientific literature on single muscle fibers.
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Affiliation(s)
- Walter R Frontera
- Department of Physical Medicine and Rehabilitation, Vanderbilt University School of Medicine, Suite 1318, 2201 Children's Way, Nashville, TN, 37212, USA,
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22
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Jayasinghe ID, Clowsley AH, Munro M, Hou Y, Crossman DJ, Soeller C. Revealing T-Tubules in Striated Muscle with New Optical Super-Resolution Microscopy Techniquess. Eur J Transl Myol 2014; 25:4747. [PMID: 26913143 PMCID: PMC4748971 DOI: 10.4081/ejtm.2015.4747] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2014] [Accepted: 12/18/2014] [Indexed: 01/03/2023] Open
Abstract
The t-tubular system plays a central role in the synchronisation of calcium signalling and excitation-contraction coupling in most striated muscle cells. Light microscopy has been used for imaging t-tubules for well over 100 years and together with electron microscopy (EM), has revealed the three-dimensional complexities of the t-system topology within cardiomyocytes and skeletal muscle fibres from a range of species. The emerging super-resolution single molecule localisation microscopy (SMLM) techniques are offering a near 10-fold improvement over the resolution of conventional fluorescence light microscopy methods, with the ability to spectrally resolve nanometre scale distributions of multiple molecular targets. In conjunction with the next generation of electron microscopy, SMLM has allowed the visualisation and quantification of intricate t-tubule morphologies within large areas of muscle cells at an unprecedented level of detail. In this paper, we review recent advancements in the t-tubule structural biology with the utility of various microscopy techniques. We outline the technical considerations in adapting SMLM to study t-tubules and its potential to further our understanding of the molecular processes that underlie the sub-micron scale structural alterations observed in a range of muscle pathologies.
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Affiliation(s)
| | | | - Michelle Munro
- Department of Physiology, The University of Auckland , New Zealand
| | - Yufeng Hou
- Department of Physiology, The University of Auckland , New Zealand
| | - David J Crossman
- Department of Physiology, The University of Auckland , New Zealand
| | - Christian Soeller
- Biomedical Physics, University of Exeter, UK, New Zealand; Biomedical Physics, University of Exeter, UK, New Zealand
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23
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Abstract
The transverse tubular (t)-system of skeletal muscle couples sarcolemmal electrical excitation with contraction deep within the fibre. Exercise, pathology and the composition of the extracellular fluid (ECF) can alter t-system volume (t-volume). T-volume changes are thought to contribute to fatigue, rhabdomyolysis and disruption of excitation–contraction coupling. However, mechanisms that underlie t-volume changes are poorly understood. A multicompartment, history-independent computer model of rat skeletal muscle was developed to define the minimum conditions for t-volume stability. It was found that the t-system tends to swell due to net ionic fluxes from the ECF across the access resistance. However, a stable t-volume is possible when this is offset by a net efflux from the t-system to the cell and thence to the ECF, forming a net ion cycle ECF→t-system→sarcoplasm→ECF that ultimately depends on Na+/K+-ATPase activity. Membrane properties that maximize this circuit flux decrease t-volume, including PNa(t) > PNa(s), PK(t) < PK(s) and N(t) < N(s) [P, permeability; N, Na+/K+-ATPase density; (t), t-system membrane; (s), sarcolemma]. Hydrostatic pressures, fixed charges and/or osmoles in the t-system can influence the magnitude of t-volume changes that result from alterations in this circuit flux. Using a parameter set derived from literature values where possible, this novel theory of t-volume was tested against data from previous experiments where t-volume was measured during manipulations of ECF composition. Predicted t-volume changes correlated satisfactorily. The present work provides a robust, unifying theoretical framework for understanding the determinants of t-volume.
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Affiliation(s)
- Jingwei Sim
- Physiological Laboratory, University of Cambridge, Downing Street, Cambridge, CB2 3EG, UK
| | - James A Fraser
- Physiological Laboratory, University of Cambridge, Downing Street, Cambridge, CB2 3EG, UK
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24
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Cully TR, Edwards JN, Launikonis BS. Activation and propagation of Ca2+ release from inside the sarcoplasmic reticulum network of mammalian skeletal muscle. J Physiol 2014; 592:3727-46. [PMID: 24973406 DOI: 10.1113/jphysiol.2014.274274] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Skeletal muscle fibres are large and highly elongated cells specialized for producing the force required for posture and movement. The process of controlling the production of force within the muscle, known as excitation-contraction coupling, requires virtually simultaneous release of large amounts of Ca(2+) from the sarcoplasmic reticulum (SR) at the level of every sarcomere within the muscle fibre. Here we imaged Ca(2+) movements within the SR, tubular (t-) system and in the cytoplasm to observe that the SR of skeletal muscle is a connected network capable of allowing diffusion of Ca(2+) within its lumen to promote the propagation of Ca(2+) release throughout the fibre under conditions where inhibition of SR ryanodine receptors (RyRs) was reduced. Reduction of cytoplasmic [Mg(2+)] ([Mg(2+)]cyto) induced a leak of Ca(2+) through RyRs, causing a reduction in SR Ca(2+) buffering power argued to be due to a breakdown of SR calsequestrin polymers, leading to a local elevation of [Ca(2+)]SR. The local rise in [Ca(2+)]SR, an intra-SR Ca(2+) transient, induced a local diffusely rising [Ca(2+)]cyto. A prolonged Ca(2+) wave lasting tens of seconds or more was generated from these events. Ca(2+) waves were dependent on the diffusion of Ca(2+) within the lumen of the SR and ended as [Ca(2+)]SR dropped to low levels to inactivate RyRs. Inactivation of RyRs allowed re-accumulation of [Ca(2+)]SR and the activation of secondary Ca(2+) waves in the persistent presence of low [Mg(2+)]cyto if the threshold [Ca(2+)]SR for RyR opening could be reached. Secondary Ca(2+) waves occurred without an abrupt reduction in SR Ca(2+) buffering power. Ca(2+) release and wave propagation occurred in the absence of Ca(2+)-induced Ca(2+) release. These observations are consistent with the activation of Ca(2+) release through RyRs of lowered cytoplasmic inhibition by [Ca(2+)]SR or store overload-induced Ca(2+) release. Restitution of SR Ca(2+) buffering power to its initially high value required imposing normal resting ionic conditions in the cytoplasm, which re-imposed the normal resting inhibition on the RyRs, allowing [Ca(2+)]SR to return to endogenous levels without activation of store overload-induced Ca(2+) release. These results are discussed in the context of how pathophysiological Ca(2+) release such as that occurring in malignant hyperthermia can be generated.
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Affiliation(s)
- Tanya R Cully
- School of Biomedical Sciences, The University of Queensland, Brisbane, QLD, 4072, Australia
| | - Joshua N Edwards
- School of Biomedical Sciences, The University of Queensland, Brisbane, QLD, 4072, Australia
| | - Bradley S Launikonis
- School of Biomedical Sciences, The University of Queensland, Brisbane, QLD, 4072, Australia
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