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Watanabe D, Nishi M, Liu F, Bian Y, Takeshima H. Ca 2+ storage function is altered in the sarcoplasmic reticulum of skeletal muscle lacking mitsugumin 23. Am J Physiol Cell Physiol 2024; 326:C795-C809. [PMID: 38223925 DOI: 10.1152/ajpcell.00440.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2023] [Revised: 12/26/2023] [Accepted: 01/05/2024] [Indexed: 01/16/2024]
Abstract
Mitsugumin 23 (MG23) has been identified as a ball-shaped cation channel in the sarcoplasmic reticulum (SR) but its physiological role remains unclear. This study aimed to examine the contribution of MG23 to Ca2+ storage function in skeletal muscle by using Mg23-knockout (Mg23-/-) mice. There was no difference in the isometric specific force of the extensor digitorum longus (EDL) and soleus (SOL) muscles between Mg23-/- and wild-type (Wt) mice. In Mg23-/- mice, the calsequestrin 2 content in the EDL muscle and SR Ca2+-ATPase 2 content in the SOL were increased. We have examined SR and myofibril functions using mechanically skinned fibers and determined their fiber types based on the response to Sr2+, which showed that Mg23-/- mice, compared with Wt, had: 1) elevated total Ca2+ content in the membranous components including SR, mitochondria, and transverse tubular system referred to as endogenous Ca2+ content, in both type I and II fibers of the EDL and SOL; 2) increased maximal Ca2+ content in both type I and II fibers of the EDL and SOL; 3) decreased SR Ca2+ leakage in type I fibers of the SOL; and 4) enhanced SR Ca2+ uptake in type I fibers of the SOL, although myofibril function was not different in both type I and II fibers of the SOL and EDL muscles. These results suggest that MG23 decreases SR Ca2+ storage in both type I and type II fibers, likely due to increased SR Ca2+ leakage.NEW & NOTEWORTHY The function of calcium storage within sarcoplasmic reticulum (SR) plays a pivotal role in influencing the health and disease states of skeletal muscle. In the present study, we demonstrated that mitsgumin 23, a novel non-selective cation channel, modifies SR Ca2+ storage in skeletal muscle fibers. These findings provide valuable insights into the physiological regulation of Ca2+ in skeletal muscle, offering significant potential for uncovering the mechanisms underlying muscle fatigue, muscle adaptation, and muscle diseases.
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Affiliation(s)
- Daiki Watanabe
- Graduate School of Sport and Health Sciences, Osaka University of Health and Sport Sciences, Osaka, Japan
| | - Miyuki Nishi
- Graduate School of Pharmaceutical Sciences, Kyoto University, Kyoto, Japan
| | - Feng Liu
- Graduate School of Pharmaceutical Sciences, Kyoto University, Kyoto, Japan
| | - Yuhan Bian
- Graduate School of Pharmaceutical Sciences, Kyoto University, Kyoto, Japan
| | - Hiroshi Takeshima
- Graduate School of Pharmaceutical Sciences, Kyoto University, Kyoto, Japan
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2
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Granic A, Suetterlin K, Shavlakadze T, Grounds M, Sayer A. Hallmarks of ageing in human skeletal muscle and implications for understanding the pathophysiology of sarcopenia in women and men. Clin Sci (Lond) 2023; 137:1721-1751. [PMID: 37986616 PMCID: PMC10665130 DOI: 10.1042/cs20230319] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2023] [Revised: 11/01/2023] [Accepted: 11/14/2023] [Indexed: 11/22/2023]
Abstract
Ageing is a complex biological process associated with increased morbidity and mortality. Nine classic, interdependent hallmarks of ageing have been proposed involving genetic and biochemical pathways that collectively influence ageing trajectories and susceptibility to pathology in humans. Ageing skeletal muscle undergoes profound morphological and physiological changes associated with loss of strength, mass, and function, a condition known as sarcopenia. The aetiology of sarcopenia is complex and whilst research in this area is growing rapidly, there is a relative paucity of human studies, particularly in older women. Here, we evaluate how the nine classic hallmarks of ageing: genomic instability, telomere attrition, epigenetic alterations, loss of proteostasis, deregulated nutrient sensing, mitochondrial dysfunction, cellular senescence, stem cell exhaustion, and altered intercellular communication contribute to skeletal muscle ageing and the pathophysiology of sarcopenia. We also highlight five novel hallmarks of particular significance to skeletal muscle ageing: inflammation, neural dysfunction, extracellular matrix dysfunction, reduced vascular perfusion, and ionic dyshomeostasis, and discuss how the classic and novel hallmarks are interconnected. Their clinical relevance and translational potential are also considered.
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Affiliation(s)
- Antoneta Granic
- AGE Research Group, Translational and Clinical Research Institute, Faculty of Medical Sciences, Newcastle University, U.K
- NIHR Newcastle Biomedical Research Centre, Newcastle University and Newcastle Upon Tyne Hospitals NHS Foundation Trust, Newcastle Upon Tyne, U.K
| | - Karen Suetterlin
- AGE Research Group, Translational and Clinical Research Institute, Faculty of Medical Sciences, Newcastle University, U.K
- NIHR Newcastle Biomedical Research Centre, Newcastle University and Newcastle Upon Tyne Hospitals NHS Foundation Trust, Newcastle Upon Tyne, U.K
- John Walton Muscular Dystrophy Research Centre, Institute of Genetic Medicine, Newcastle University, Centre for Life, Newcastle upon Tyne, U.K
| | - Tea Shavlakadze
- Regeneron Pharmaceuticals Inc., Tarrytown, New York, NY, U.S.A
| | - Miranda D. Grounds
- Department of Anatomy, Physiology and Human Biology, School of Human Sciences, the University of Western Australia, Perth, WA 6009, Australia
| | - Avan A. Sayer
- AGE Research Group, Translational and Clinical Research Institute, Faculty of Medical Sciences, Newcastle University, U.K
- NIHR Newcastle Biomedical Research Centre, Newcastle University and Newcastle Upon Tyne Hospitals NHS Foundation Trust, Newcastle Upon Tyne, U.K
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3
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Wrucke DJ, Kuplic A, Adam M, Hunter SK, Sundberg CW. Neural and muscular contributions to the age-related loss in power of the knee extensors in men and women. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.10.24.563851. [PMID: 37961177 PMCID: PMC10634815 DOI: 10.1101/2023.10.24.563851] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2023]
Abstract
The mechanisms for the loss in limb muscle power in old (60-79 years) and very old (≥80 years) adults and whether the mechanisms differ between men and women are not well-understood. We compared maximal power of the knee extensor muscles between young, old, and very old men and women and identified the neural and muscular factors contributing to the age-related loss of power. 31 young (22.9±3.0 years, 15 women), 83 old (70.4±4.9 years, 39 women), and 16 very old adults (85.8±4.2 years, 9 women) performed maximal isokinetic contractions at 14 different velocities (30-450°/s) to identify peak power. Voluntary activation (VA) and contractile properties were assessed with transcranial magnetic stimulation to the motor cortex and electrical stimulation of the femoral nerve. The age-related loss in power was ~6.5 W·year-1 for men (R2=0.62, p<0.001), which was a greater rate of decline (p=0.002) than the ~4.2 W·year-1 for women (R2=0.77, p<0.001). Contractile properties were the most closely associated variables with power output for both sexes, such as the rate of torque development of the potentiated twitch (men: R2=0.69, p<0.001; women: R2=0.57, p<0.001). VA was weakly associated with power in women (R2=0.13, p=0.012) but not men (p=0.191), whereas neuromuscular activation (EMG amplitude) during the maximal power contraction was not associated with power in men (p=0.347) or women (p=0.106). These data suggest that the age-related loss in power of the knee extensor muscles is due primarily to factors within the muscle for both sexes, although neural factors may play a minor role in older women.
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Affiliation(s)
- David J. Wrucke
- Exercise and Rehabilitation Sciences Program, Department of Physical Therapy, Marquette University, Milwaukee, WI, USA
| | - Andrew Kuplic
- Exercise and Rehabilitation Sciences Program, Department of Physical Therapy, Marquette University, Milwaukee, WI, USA
| | - Mitchell Adam
- Exercise and Rehabilitation Sciences Program, Department of Physical Therapy, Marquette University, Milwaukee, WI, USA
| | - Sandra K. Hunter
- Exercise and Rehabilitation Sciences Program, Department of Physical Therapy, Marquette University, Milwaukee, WI, USA
- Athletic and Human Performance Research Center, Marquette University, Milwaukee, WI, USA
| | - Christopher W. Sundberg
- Exercise and Rehabilitation Sciences Program, Department of Physical Therapy, Marquette University, Milwaukee, WI, USA
- Athletic and Human Performance Research Center, Marquette University, Milwaukee, WI, USA
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4
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Kim MY, Shin HY, Cho SC, Yang S, Intisar A, Woo HJ, Choi YS, You CL, Kang JS, Lee YI, Park SC, Yea K, Oh TG, Downes M, Evans RM, Kim MS. Silver electroceutical technology to treat sarcopenia. Proc Natl Acad Sci U S A 2023; 120:e2300036120. [PMID: 37549292 PMCID: PMC10438839 DOI: 10.1073/pnas.2300036120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2023] [Accepted: 06/22/2023] [Indexed: 08/09/2023] Open
Abstract
While the world is rapidly transforming into a superaging society, pharmaceutical approaches to treat sarcopenia have hitherto not been successful due to their insufficient efficacy and failure to specifically target skeletal muscle cells (skMCs). Although electrical stimulation (ES) is emerging as an alternative intervention, its efficacy toward treating sarcopenia remains unexplored. In this study, we demonstrate a silver electroceutical technology with the potential to treat sarcopenia. First, we developed a high-throughput ES screening platform that can simultaneously stimulate 15 independent conditions, while utilizing only a small number of human-derived primary aged/young skMCs (hAskMC/hYskMC). The in vitro screening showed that specific ES conditions induced hypertrophy and rejuvenation in hAskMCs, and the optimal ES frequency in hAskMCs was different from that in hYskMCs. When applied to aged mice in vivo, specific ES conditions improved the prevalence and thickness of Type IIA fibers, along with biomechanical attributes, toward a younger skMC phenotype. This study is expected to pave the way toward an electroceutical treatment for sarcopenia with minimal side effects and help realize personalized bioelectronic medicine.
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Affiliation(s)
- Min Young Kim
- Department of New Biology, Daegu Gyeongbuk Institute of Science and Technology, Daegu42988, Republic of Korea
| | - Hyun Young Shin
- CTCELLS, Inc., Daegu42988, Republic of Korea
- SBCure Corp., Daegu43017, Republic of Korea
| | - Sung Chun Cho
- Well Aging Research Center, Daegu Gyeongbuk Institute of Science and Technology, Daegu42988, Republic of Korea
| | - Sohae Yang
- Department of New Biology, Daegu Gyeongbuk Institute of Science and Technology, Daegu42988, Republic of Korea
| | - Aseer Intisar
- Department of New Biology, Daegu Gyeongbuk Institute of Science and Technology, Daegu42988, Republic of Korea
| | - Hyeong Jung Woo
- Department of New Biology, Daegu Gyeongbuk Institute of Science and Technology, Daegu42988, Republic of Korea
| | - Youn-Suk Choi
- Samsung Advanced Institute of Technology, Samsung Electronics Co. Ltd., Suwon16678, Republic of Korea
| | - Chang-Lim You
- Department of Molecular Cell Biology, Sungkyunkwan University School of Medicine, Suwon16419, Republic of Korea
| | - Jong-Sun Kang
- Department of Molecular Cell Biology, Sungkyunkwan University School of Medicine, Suwon16419, Republic of Korea
| | - Yun-Il Lee
- Well Aging Research Center, Daegu Gyeongbuk Institute of Science and Technology, Daegu42988, Republic of Korea
| | - Sang Chul Park
- Chonnam National University Medical School, Gwangju61186, Republic of Korea
| | - Kyungmoo Yea
- Department of New Biology, Daegu Gyeongbuk Institute of Science and Technology, Daegu42988, Republic of Korea
| | - Tae Gyu Oh
- Gene Expression Laboratory, Salk Institute for Biological Studies, La Jolla, CA92037
| | - Michael Downes
- Gene Expression Laboratory, Salk Institute for Biological Studies, La Jolla, CA92037
| | - Ronald M. Evans
- Gene Expression Laboratory, Salk Institute for Biological Studies, La Jolla, CA92037
| | - Minseok S. Kim
- Department of New Biology, Daegu Gyeongbuk Institute of Science and Technology, Daegu42988, Republic of Korea
- CTCELLS, Inc., Daegu42988, Republic of Korea
- Translational Responsive Medicine Center, Daegu Gyeongbuk Institute of Science and Technology, Daegu42988, Republic of Korea
- New Biology Research Center, Daegu Gyeongbuk Institute of Science and Technology, Daegu42988, Republic of Korea
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5
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Wang F, Jiang Y, Hou L. Effects of different exercise intensities on motor skill learning capability and process. Sci Sports 2022. [DOI: 10.1016/j.scispo.2021.09.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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6
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Pani P, Bal NC. Avian adjustments to cold and non-shivering thermogenesis: whats, wheres and hows. Biol Rev Camb Philos Soc 2022; 97:2106-2126. [PMID: 35899483 DOI: 10.1111/brv.12885] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2021] [Revised: 06/27/2022] [Accepted: 06/28/2022] [Indexed: 11/28/2022]
Abstract
Avian cold adaptation is hallmarked by innovative strategies of both heat conservation and thermogenesis. While minimizing heat loss can reduce the thermogenic demands of body temperature maintenance, it cannot eliminate the requirement for thermogenesis. Shivering and non-shivering thermogenesis (NST) are the two synergistic mechanisms contributing to endothermy. Birds are of particular interest in studies of NST as they lack brown adipose tissue (BAT), the major organ of NST in mammals. Critical analysis of the existing literature on avian strategies of cold adaptation suggests that skeletal muscle is the principal site of NST. Despite recent progress, isolating the mechanisms involved in avian muscle NST has been difficult as shivering and NST co-exist with its primary locomotory function. Herein, we re-evaluate various proposed molecular bases of avian skeletal muscle NST. Experimental evidence suggests that sarco(endo)plasmic reticulum Ca2+ -ATPase (SERCA) and ryanodine receptor 1 (RyR1) are key in avian muscle NST, through their mediation of futile Ca2+ cycling and thermogenesis. More recent studies have shown that SERCA regulation by sarcolipin (SLN) facilitates muscle NST in mammals; however, its role in birds is unclear. Ca2+ signalling in the muscle seems to be common to contraction, shivering and NST, but elucidating its roles will require more precise measurement of local Ca2+ levels inside avian myofibres. The endocrine control of avian muscle NST is still poorly defined. A better understanding of the mechanistic details of avian muscle NST will provide insights into the roles of these processes in regulatory thermogenesis, which could further inform our understanding of the evolution of endothermy among vertebrates.
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Affiliation(s)
- Punyadhara Pani
- School of Biotechnology, KIIT University, Bhubaneswar, Odisha, 751024, India
| | - Naresh C Bal
- School of Biotechnology, KIIT University, Bhubaneswar, Odisha, 751024, India
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7
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Tripp TR, Frankish BP, Lun V, Wiley JP, Shearer J, Murphy RM, MacInnis MJ. Time course and fibre type-dependent nature of calcium-handling protein responses to sprint interval exercise in human skeletal muscle. J Physiol 2022; 600:2897-2917. [PMID: 35556249 DOI: 10.1113/jp282739] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2022] [Accepted: 04/22/2022] [Indexed: 11/08/2022] Open
Abstract
KEY POINTS Sprint interval training (SIT) has been shown to cause fragmentation of the sarcoplasmic reticulum calcium-release channel, ryanodine receptor 1 (RyR1) 24 hours post-exercise, which may act as a signal for mitochondrial biogenesis. In this study, we examined the time course of RyR1 fragmentation in human whole muscle and pooled type I and type II skeletal muscle fibres following a single session of SIT. Full-length RyR1 protein content was significantly lower than pre-exercise by 6 h post-SIT in whole muscle, and fragmentation was detectable in type II but not type I fibres, though to a lesser extent than in whole muscle. The peak in PGC1A mRNA expression occurred earlier than RyR1 fragmentation. The increased temporal resolution and fibre type-specific responses for RyR1 fragmentation provide insights into its importance to mitochondrial biogenesis in humans. ABSTRACT Sprint interval training (SIT) causes fragmentation of the skeletal muscle sarcoplasmic reticulum Ca2+ release channel, ryanodine receptor 1 (RyR1), 24h post-exercise, potentially signaling mitochondrial biogenesis by increasing cytosolic [Ca2+ ]. Yet, the time course and skeletal muscle fibre type-specific patterns of RyR1 fragmentation following a session of SIT remain unknown. Ten participants (n = 4 females; n = 6 males) performed a session of SIT (6 × 30 s "all-out" with 4.5 min rest after each sprint) with vastus lateralis muscle biopsy samples collected before and 3, 6, and 24h after exercise. In whole muscle, full-length RyR1 protein content was significantly reduced 6 h (mean [SD]; -38 [38]%; p<0.05) and 24 h post-SIT (-30 [48]%; p<0.05) compared to pre-exercise. Examining each participant's largest response in pooled samples, full-length RyR1 protein content was reduced in type II (-26 [30]%; p<0.05) but not type I fibres (-11 [40]%; p>0.05). 3h post-SIT, there was also a decrease in SERCA1 in type II fibres (-23 [17]%; p<0.05) and SERCA2a in type I fibres (-19 [21]%; p<0.05), despite no time effect for either protein in whole muscle samples (p>0.05). PGC1A mRNA content was elevated 3h and 6h post-SIT (5.3- and 3.7-fold change from pre, respectively; p<0.05 for both), but peak PGC1A mRNA expression was not significantly correlated with peak RyR1 fragmentation (r2 = 0.10; p>0.05). In summary, altered Ca2+ -handling protein expression, which occurs primarily in type II muscle fibres, may influence signals for mitochondrial biogenesis as early as 3-6 h post-SIT in humans. Abstract figure legend Western blotting was performed on whole muscle and pooled type I and II muscle fibre preparations derived from human vastus lateralis muscle biopsy samples collected before and after a single session of sprint interval training (SIT). Full-length ryanodine receptor 1 (RyR1) protein content was reduced 6 and 24 h post-exercise in whole muscle samples compared to baseline, despite a heterogeneous time course among individuals. This RyR1 fragmentation proceeded and outlasted the increase in peroxisome proliferator-activated γ receptor coactivator 1α (PGC1A) mRNA expression. When examining the time point of each individual's peak response, RyR1 fragmentation was evident in type II, but not type I, muscle fibres. These findings suggest that, in humans, mitochondrial biogenesis could be influenced by RyR1 fragmentation 3-6 h post-SIT in a fibre type-dependent manner. Created with BioRender.com. This article is protected by copyright. All rights reserved.
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Affiliation(s)
- Thomas R Tripp
- Faculty of Kinesiology, University of Calgary, Calgary, Alberta, Canada
| | - Barnaby P Frankish
- Faculty of Kinesiology, University of Calgary, Calgary, Alberta, Canada.,Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, Melbourne, Australia
| | - Victor Lun
- University of Calgary Sport Medicine Centre, Faculty of Kinesiology, University of Calgary, Calgary, Alberta, Canada
| | - J Preston Wiley
- Faculty of Kinesiology, University of Calgary, Calgary, Alberta, Canada.,University of Calgary Sport Medicine Centre, Faculty of Kinesiology, University of Calgary, Calgary, Alberta, Canada
| | - Jane Shearer
- Faculty of Kinesiology, University of Calgary, Calgary, Alberta, Canada.,Department of Biochemistry & Molecular Biology, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Robyn M Murphy
- Department of Physiology, Anatomy and Microbiology, School of Life Sciences, La Trobe University, Melbourne, Australia
| | - Martin J MacInnis
- Faculty of Kinesiology, University of Calgary, Calgary, Alberta, Canada
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8
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Coletti C, Acosta GF, Keslacy S, Coletti D. Exercise-mediated reinnervation of skeletal muscle in elderly people: An update. Eur J Transl Myol 2022; 32. [PMID: 35234025 PMCID: PMC8992679 DOI: 10.4081/ejtm.2022.10416] [Citation(s) in RCA: 26] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2022] [Accepted: 02/17/2022] [Indexed: 11/22/2022] Open
Abstract
Sarcopenia is defined by the loss of muscle mass and function. In aging sarcopenia is due to mild chronic inflammation but also to fiber-intrinsic defects, such as mitochondrial dysfunction. Age-related sarcopenia is associated with physical disability and lowered quality of life. In addition to skeletal muscle, the nervous tissue is also affected in elderly people. With aging, type 2 fast fibers preferentially undergo denervation and are reinnervated by slow-twitch motor neurons. They spread forming new neuro-muscular junctions with the denervated fibers: the result is an increased proportion of slow fibers that group together since they are associated in the same motor unit. Grouping and fiber type shifting are indeed major histological features of aging skeletal muscle. Exercise has been proposed as an intervention for age-related sarcopenia due to its numerous beneficial effects on muscle mechanical and biochemical features. In 2013, a precursor study in humans was published in the European Journal of Translation Myology (formerly known as Basic and Applied Myology), highlighting the occurrence of reinnervation in the musculature of aged, exercise-trained individuals as compared to the matching control. This paper, entitled «Reinnervation of Vastus lateralis is increased significantly in seniors (70-years old) with a lifelong history of high-level exercise», is now being reprinted for the second issue of the «Ejtm Seminal Paper Series». In this short review we discuss those results in the light of the most recent advances confirming the occurrence of exercise-mediated reinnervation, ultimately preserving muscle structure and function in elderly people who exercise.
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Affiliation(s)
- Claudia Coletti
- School of Kinesiology, Nutrition and Food Science, California State University Los Angeles, Los Angeles, CA.
| | - Gilberto F Acosta
- School of Kinesiology, Nutrition and Food Science, California State University Los Angeles, Los Angeles, CA.
| | - Stefan Keslacy
- School of Kinesiology, Nutrition and Food Science, California State University Los Angeles, Los Angeles, CA.
| | - Dario Coletti
- DAHFMO - Unit of Histology and Medical Embryology, Sapienza University of Rome, Rome, Italy; Biological Adaptation and Ageing, CNRS UMR 8256, Inserm U1164, Institut de Biologie Paris-Seine, Sorbonne Université, Paris, France; Interuniversity institute of Myology, Ro.
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9
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De Gasperi R, Mo C, Azulai D, Wang Z, Harlow LM, Du Y, Graham Z, Pan J, Liu XH, Guo L, Zhang B, Ko F, Raczkowski AM, Bauman WA, Goulbourne CN, Zhao W, Brotto M, Cardozo CP. Numb is required for optimal contraction of skeletal muscle. J Cachexia Sarcopenia Muscle 2022; 13:454-466. [PMID: 35001540 PMCID: PMC8818612 DOI: 10.1002/jcsm.12907] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/29/2021] [Revised: 11/12/2021] [Accepted: 11/28/2021] [Indexed: 12/21/2022] Open
Abstract
BACKGROUND The role of Numb, a protein that is important for cell fate and development and that, in human muscle, is expressed at reduced levels with advanced age, was investigated; adult mice skeletal muscle and its localization and function within myofibres were determined. METHODS Numb expression was evaluated by western blot. Numb localization was determined by confocal microscopy. The effects of conditional knock out (cKO) of Numb and the closely related gene Numb-like in skeletal muscle fibres were evaluated by in situ physiology, transmission and focused ion beam scanning electron microscopy, three-dimensional reconstruction of mitochondria, lipidomics, and bulk RNA sequencing. Additional studies using primary mouse myotubes investigated the effects of Numb knockdown on cell fusion, mitochondrial function, and calcium transients. RESULTS Numb protein expression was reduced by ~70% (P < 0.01) at 24 as compared with 3 months of age in gastrocnemius and tibialis anterior muscle. Numb was localized within muscle fibres as bands traversing fibres at regularly spaced intervals in close proximity to dihydropyridine receptors. The cKO of Numb and Numb-like reduced specific tetanic force by 36% (P < 0.01), altered mitochondrial spatial relationships to sarcomeric structures, increased Z-line spacing by 30% (P < 0.0001), perturbed sarcoplasmic reticulum organization and reduced mitochondrial volume by over 80% (P < 0.01). Only six genes were differentially expressed in cKO mice: Itga4, Sema7a, Irgm2, Vezf1, Mib1, and Tmem132a. Several lipid mediators derived from polyunsaturated fatty acids through lipoxygenases were up-regulated in Numb cKO skeletal muscle: 12-HEPE was increased by ~250% (P < 0.05) and 17,18-EpETE by ~240% (P < 0.05). In mouse primary myotubes, Numb knockdown reduced cell fusion (~20%, P < 0.01) and delayed the caffeine-induced rise in cytosolic calcium concentrations by more than 100% (P < 0.01). CONCLUSIONS These findings implicate Numb as a critical factor in skeletal muscle structure and function and suggest that Numb is critical for calcium release. We therefore speculate that Numb plays critical roles in excitation-contraction coupling, one of the putative targets of aged skeletal muscles. These findings provide new insights into the molecular underpinnings of the loss of muscle function observed with sarcopenia.
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Affiliation(s)
- Rita De Gasperi
- National Center for the Medical Consequences of Spinal Cord Injury, James J. Peters VA, Bronx, NY, USA.,Department of Psychiatry and Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Chenglin Mo
- Bone-Muscle Research Center, College of Nursing & Health Innovation, The University of Texas at Arlington, Arlington, TX, USA
| | - Daniella Azulai
- National Center for the Medical Consequences of Spinal Cord Injury, James J. Peters VA, Bronx, NY, USA
| | - Zhiying Wang
- Bone-Muscle Research Center, College of Nursing & Health Innovation, The University of Texas at Arlington, Arlington, TX, USA
| | - Lauren M Harlow
- National Center for the Medical Consequences of Spinal Cord Injury, James J. Peters VA, Bronx, NY, USA
| | - Yating Du
- Bone-Muscle Research Center, College of Nursing & Health Innovation, The University of Texas at Arlington, Arlington, TX, USA
| | - Zachary Graham
- National Center for the Medical Consequences of Spinal Cord Injury, James J. Peters VA, Bronx, NY, USA.,Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Jiangping Pan
- National Center for the Medical Consequences of Spinal Cord Injury, James J. Peters VA, Bronx, NY, USA
| | - Xin-Hua Liu
- National Center for the Medical Consequences of Spinal Cord Injury, James J. Peters VA, Bronx, NY, USA.,Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Lei Guo
- Department of Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, NY, USA.,Mount Sinai Center for Transformative Disease Modeling, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Bin Zhang
- Department of Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, NY, USA.,Mount Sinai Center for Transformative Disease Modeling, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Fred Ko
- Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, NY, USA.,Department of Geriatrics and Palliative Medicine, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | | | - William A Bauman
- National Center for the Medical Consequences of Spinal Cord Injury, James J. Peters VA, Bronx, NY, USA.,Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, NY, USA.,Department of Rehabilitation Medicine, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Chris N Goulbourne
- Center for Dementia Research, Nathan S. Kline Institute, Orangeburg, NY, USA
| | - Wei Zhao
- National Center for the Medical Consequences of Spinal Cord Injury, James J. Peters VA, Bronx, NY, USA.,Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Marco Brotto
- Bone-Muscle Research Center, College of Nursing & Health Innovation, The University of Texas at Arlington, Arlington, TX, USA
| | - Christopher P Cardozo
- National Center for the Medical Consequences of Spinal Cord Injury, James J. Peters VA, Bronx, NY, USA.,Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, NY, USA.,Department of Rehabilitation Medicine, Icahn School of Medicine at Mount Sinai, New York, NY, USA
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10
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Suetterlin KJ, Tan SV, Mannikko R, Phadke R, Orford M, Eaton S, Sayer AA, Grounds MD, Matthews E, Greensmith L, Hanna MG. Ageing contributes to phenotype transition in a mouse model of periodic paralysis. JCSM RAPID COMMUNICATIONS 2021; 4:245-259. [PMID: 35174322 PMCID: PMC8837191 DOI: 10.1002/rco2.41] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/06/2020] [Revised: 03/11/2021] [Accepted: 04/07/2021] [Indexed: 05/03/2023]
Abstract
BACKGROUND Periodic paralysis (PP) is a rare genetic disorder in which ion channel mutation causes episodic paralysis in association with hyper- or hypokalaemia. An unexplained but consistent feature of PP is that a phenotype transition occurs around the age of 40, in which the severity of potassium-induced muscle weakness declines but onset of fixed, progressive weakness is reported. This phenotype transition coincides with the age at which muscle mass and optimal motor function start to decline in healthy individuals. We sought to determine if the phenotype transition in PP is linked to the normal ageing phenotype transition and to explore the mechanisms involved. METHODS A mouse model of hyperkalaemic PP was compared with wild-type littermates across a range of ages (13-104 weeks). Only male mice were used as penetrance is incomplete in females. We adapted the muscle velocity recovery cycle technique from humans to examine murine muscle excitability in vivo. We then examined changes in potassium-induced weakness or caffeine contracture force with age using ex vivo muscle tension testing. Muscles were further characterized by either Western blot, histology or energy charge measurement. For normally distributed data, a student's t-test (± Welch correction) or one- or two-way analysis of variance (ANOVA) was performed to determine significance. For data that were not normally distributed, Welch rank test, Mann Whitney U test or Kruskal-Wallis ANOVA was performed. When an ANOVA was significant (P < 0.05), post hoc Tukey testing was used. RESULTS Both WT (P = 0.009) and PP (P = 0.007) muscles exhibit increased resistance to potassium-induced weakness with age. Our data suggest that healthy-old muscle develops mechanisms to maintain force despite sarcolemmal depolarization and sodium channel inactivation. In contrast, reduced caffeine contracture force (P = 0.00005), skeletal muscle energy charge (P = 0.004) and structural core pathology (P = 0.005) were specific to Draggen muscle, indicating that they are caused, or at least accelerated by, chronic genetic ion channel dysfunction. CONCLUSIONS The phenotype transition with age is replicated in a mouse model of PP. Intrinsic muscle ageing protects against potassium-induced weakness in HyperPP mice. However, it also appears to accelerate impairment of sarcoplasmic reticulum calcium release, mitochondrial impairment and the development of core-like regions, suggesting acquired RyR1 dysfunction as the potential aetiology. This work provides a first description of mechanisms involved in phenotype transition with age in PP. It also demonstrates how studying phenotype transition with age in monogenic disease can yield novel insights into both disease physiology and the ageing process itself.
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Affiliation(s)
- Karen J. Suetterlin
- Department of Neuromuscular DiseasesUCL Queen Square Institute of NeurologyLondonUK
- MRC Centre for Neuromuscular DiseasesUCL Queen Square Institute of Neurology and National Hospital for Neurology and NeurosurgeryLondonUK
- AGE Research Group, NIHR Newcastle Biomedical Research CentreNewcastle upon Tyne Hospitals NHS Foundation Trust and Newcastle UniversityNewcastle upon TyneUK
| | - S. Veronica Tan
- MRC Centre for Neuromuscular DiseasesUCL Queen Square Institute of Neurology and National Hospital for Neurology and NeurosurgeryLondonUK
- Guy's and St Thomas' NHS Foundation TrustLondonUK
| | - Roope Mannikko
- Department of Neuromuscular DiseasesUCL Queen Square Institute of NeurologyLondonUK
- MRC Centre for Neuromuscular DiseasesUCL Queen Square Institute of Neurology and National Hospital for Neurology and NeurosurgeryLondonUK
| | - Rahul Phadke
- Department of NeuropathologyGreat Ormond Street HospitalLondonUK
| | - Michael Orford
- UCL Great Ormond Street Institute of Child HealthLondonUK
| | - Simon Eaton
- UCL Great Ormond Street Institute of Child HealthLondonUK
| | - Avan A. Sayer
- AGE Research Group, NIHR Newcastle Biomedical Research CentreNewcastle upon Tyne Hospitals NHS Foundation Trust and Newcastle UniversityNewcastle upon TyneUK
| | | | - Emma Matthews
- Department of Neuromuscular DiseasesUCL Queen Square Institute of NeurologyLondonUK
- MRC Centre for Neuromuscular DiseasesUCL Queen Square Institute of Neurology and National Hospital for Neurology and NeurosurgeryLondonUK
- Atkinson Morley Neuromuscular Centre, Department of NeurologySt Georges University Hospitals NHS Foundation TrustLondonUK
| | - Linda Greensmith
- Department of Neuromuscular DiseasesUCL Queen Square Institute of NeurologyLondonUK
| | - Michael G. Hanna
- Department of Neuromuscular DiseasesUCL Queen Square Institute of NeurologyLondonUK
- MRC Centre for Neuromuscular DiseasesUCL Queen Square Institute of Neurology and National Hospital for Neurology and NeurosurgeryLondonUK
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11
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Watanabe D, Wada M. Orthograde signal of dihydropyridine receptor increases Ca 2+ leakage after repeated contractions in rat fast-twitch muscles in vivo. Am J Physiol Cell Physiol 2021; 320:C806-C821. [PMID: 33596151 DOI: 10.1152/ajpcell.00364.2020] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2020] [Accepted: 02/10/2021] [Indexed: 11/22/2022]
Abstract
The purpose of this study was to investigate the mechanism underlying sarcoplasmic reticulum (SR) Ca2+ leakage after in vivo contractions. Rat gastrocnemius muscles were electrically stimulated in vivo, and then mechanically skinned fibers and SR microsomes were prepared from the muscles excised 30 min after repeated high-intensity contractions. The mechanically skinned fibers maintained the interaction between dihydropyridine receptors (DHPRs) and ryanodine receptors (RyRs), whereas the SR microsomes did not. Interestingly, skinned fibers from the stimulated muscles showed increased SR Ca2+ leakage, whereas Ca2+ leakage decreased in SR microsomes from the stimulated muscles. To enhance the orthograde signal of DHPRs, SR Ca2+ leakage in the skinned fiber was measured 1) under a continuously depolarized condition and 2) in the presence of nifedipine. As a result, in either of the two conditions, SR Ca2+ leakage in the rested fibers reached a level similar to that in the stimulated fibers. Furthermore, the increased SR Ca2+ leakage from the stimulated fibers was alleviated by treatment with 1 mM tetracaine (Tet) but not by treatment with 3 mM free Mg2+ (3 Mg). Tet exerted a greater inhibitory effect on the DHPR signal to RyR than 3 Mg, although their inhibitory effects on RyR were almost similar. These results suggest that the increased Ca2+ leakage after muscle contractions is mainly caused by the orthograde signal of DHPRs to RyRs.
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Affiliation(s)
- Daiki Watanabe
- Graduate School of Humanities and Social Sciences, Hiroshima University, Hiroshima, Japan
| | - Masanobu Wada
- Graduate School of Humanities and Social Sciences, Hiroshima University, Hiroshima, Japan
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12
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Rate of force development is Ca 2+-dependent and influenced by Ca 2+-sensitivity in human single muscle fibres from older adults. Exp Gerontol 2021; 150:111348. [PMID: 33862138 DOI: 10.1016/j.exger.2021.111348] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2020] [Revised: 04/07/2021] [Accepted: 04/08/2021] [Indexed: 11/20/2022]
Abstract
Natural adult aging is associated with declines in skeletal muscle performance, including impaired Ca2+ sensitivity and a slowing of rapid force production (rate of force redevelopment; ktr). The purpose of this study was to investigate the relationship between impaired Ca2+ sensitivity and ktr of single muscle fibres from young and older adults. Participants included 8 young (22-35 yrs) and 8 older (60-81 yrs) males who were living independently. A percutaneous muscle biopsy of the vastus lateralis of each participant was performed. Single muscle fibre mechanical tests included maximal Ca2+-activated force (Po), force-pCa curves, and ktr. We showed a decrease in pCa50 in old type II fibres compared to young, indicating impaired Ca2+ sensitivity in older adults. The ktr behaved in a Ca2+-dependent manner such that with increasing [Ca2+], ktr increases, to a plateau. Interestingly, ktr was not different between young and old muscle fibres. Furthermore, we found strong associations between pCa50 and ktr in both old type I and type II fibres, such that those fibres with lower Ca2+ sensitivity had a slowed ktr. This Ca2+ association, combined with impaired Ca2+ handling in older adults suggests a potential Ca2+-dependent mechanism affecting the transition from weakly- to strongly-bound cross-bridge states, leading to a decline in skeletal muscle performance. Future research is needed to explore the role alterations to Ca2+ sensitivity/handling could be playing in age-related whole muscle performance declines.
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13
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Loss of α-actinin-3 during human evolution provides superior cold resilience and muscle heat generation. Am J Hum Genet 2021; 108:446-457. [PMID: 33600773 PMCID: PMC8008486 DOI: 10.1016/j.ajhg.2021.01.013] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2020] [Accepted: 01/19/2021] [Indexed: 12/12/2022] Open
Abstract
The protein α-actinin-3 expressed in fast-twitch skeletal muscle fiber is absent in 1.5 billion people worldwide due to homozygosity for a nonsense polymorphism in ACTN3 (R577X). The prevalence of the 577X allele increased as modern humans moved to colder climates, suggesting a link between α-actinin-3 deficiency and improved cold tolerance. Here, we show that humans lacking α-actinin-3 (XX) are superior in maintaining core body temperature during cold-water immersion due to changes in skeletal muscle thermogenesis. Muscles of XX individuals displayed a shift toward more slow-twitch isoforms of myosin heavy chain (MyHC) and sarcoplasmic reticulum (SR) proteins, accompanied by altered neuronal muscle activation resulting in increased tone rather than overt shivering. Experiments on Actn3 knockout mice showed no alterations in brown adipose tissue (BAT) properties that could explain the improved cold tolerance in XX individuals. Thus, this study provides a mechanism for the positive selection of the ACTN3 X-allele in cold climates and supports a key thermogenic role of skeletal muscle during cold exposure in humans.
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14
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Mijares A, Allen PD, Lopez JR. Senescence Is Associated With Elevated Intracellular Resting [Ca 2 +] in Mice Skeletal Muscle Fibers. An in vivo Study. Front Physiol 2021; 11:601189. [PMID: 33510646 PMCID: PMC7837333 DOI: 10.3389/fphys.2020.601189] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2020] [Accepted: 11/23/2020] [Indexed: 11/13/2022] Open
Abstract
Aging causes skeletal muscles to become atrophied, weak, and easily fatigued. Here, we have tested the hypothesis that normal aging in skeletal muscle cells is associated with Ca2+ intracellular dyshomeostasis and oxidative stress. Intracellular Ca2+ concentration ([Ca2+]i), resting intracellular Na+ concentration ([Na+]i) and reactive oxygen species (ROS) production were measured in vivo (superficial gastrocnemius fibers) using double-barreled ion-selective microelectrodes, and in vitro [isolated single flexor digitorum brevis fibers] using fluorescent ROS sensor CM-H2DCFDA in young (3 months of age), middle-aged (12 months of age), and aged (24 months of age) mice. We found an age-related increase in [Ca2+]i from 121 ± 4 nM in young muscle cells which rose to 255 ± 36 nM in middle-aged and to 409 ± 25 nM in aged cells. [Na+]i also showed an age-dependent elevation, increasing from 8 ± 0.5 mM in young muscle fibers, to 12 ± 1 mM in middle-aged and to 17 ± 1 mM in old muscle fibers. Using the fluorescent ROS sensor CM-H2DCFDA we found that these increases in intracellular cation concentrations were associated with significantly increased basal ROS production as demonstrated by age related increases in the rate of dichlorodihydrofluorescein fluorescence. To determine is this could be modified by reducing ROS and/or blocking sarcolemmal Ca2+ influx we administered flufenamic acid (FFA), a non-steroidal anti-inflammatory drug which is also a non-selective blocker of the transient receptor potential canonical channels (TRPCs), for 4 weeks to determine if this would have a beneficial effect. FFA treatment reduced both basal ROS production and muscle [Ca2+]i and [Na+]i in middle-aged and aged muscle fibers compared to fibers and muscles of untreated 12 and 24-months old mice. [Ca2+]i was reduced to 134 ± 8 nM in middle-aged muscle and to 246 ± 40 nM in muscle from aged mice. Likewise [Na+]i was reduced to 9 ± 0.7 mM in middle-aged muscles and to 13 ± 1 mM in muscle from aged mice. FFA treatment also reduced age associated increases in plasma interleukin 6 and tumor necrosis factor-alpha (TNF-α) concentrations which were elevated in 12 and 24-months old mice compared to young mice and decreased age-related muscle damage as indicated by a reduction in serum creatine kinase (CK) activity. Our data provides a direct demonstration that normal aging is associated with a significant elevation [Ca2+]i, [Na+]i, and intracellular ROS production in skeletal muscle fibers. Furthermore, the fact that FFA reduced the intracellular [Ca2+], [Na+], and ROS production as well as the elevated IL6, TNF-α, and CK levels, led us to suggest that its pharmacological effect may be related to its action both as a TRPC channel blocker and as an anti-inflammatory.
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Affiliation(s)
- Alfredo Mijares
- Centro de Biofísica y Bioquímica, Instituto Venezolano de Investigaciones Científicas, Caracas, Venezuela
| | - Paul D Allen
- Malignant Hyperthermia Investigation Unit, St James' University Hospital, University of Leeds, Leeds, United Kingdom
| | - Jose R Lopez
- Department of Research, Mount Sinai Medical Center, Miami, FL, United states
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15
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Zullo A, Frisso G, Carsana A. Influence of physical activity on structure and function of the RyR1 calcium channel: a systematic review. GAZZETTA MEDICA ITALIANA ARCHIVIO PER LE SCIENZE MEDICHE 2020. [DOI: 10.23736/s0393-3660.19.04238-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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16
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Cheng AJ, Ström J, Hwee DT, Malik FI, Westerblad H. Fast skeletal muscle troponin activator CK-2066260 mitigates skeletal muscle weakness independently of the underlying cause. J Cachexia Sarcopenia Muscle 2020; 11:1747-1757. [PMID: 32954682 PMCID: PMC7749611 DOI: 10.1002/jcsm.12624] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/07/2020] [Revised: 08/08/2020] [Accepted: 08/23/2020] [Indexed: 12/22/2022] Open
Abstract
BACKGROUND Muscle weakness is a common symptom in numerous diseases and a regularly occurring problem associated with ageing. Prolonged low-frequency force depression (PLFFD) is a form of exercise-induced skeletal muscle weakness observed after exercise. Three different intramuscular mechanisms underlying PLFFD have been identified: decreased sarcoplasmic reticulum Ca2+ release, decreased myofibrillar Ca2+ sensitivity, and myofibrillar dysfunction. We here used these three forms of PLFFD as models to study the effectiveness of a fast skeletal muscle troponin activator, CK-2066260, to mitigate muscle weakness. METHODS Experiments were performed on intact single muscle fibres or fibre bundles from mouse flexor digitorum brevis, which were stimulated with electrical current pulses, while force and the free cytosolic [Ca2+ ] ([Ca2+ ]i ) were measured. PLFFD was induced by three different stimulation protocols: (i) repeated isometric contractions at low intensity (350 ms tetani given every 5 s for 100 contractions); (ii) repeated isometric contractions at high intensity (250 ms tetani given every 0.5 s for 300 contractions); and (iii) repeated eccentric contractions (350 ms tetani with 20% length increase given every 20 s for 10 contractions). The extent and cause of PLFFD were assessed by comparing the force-[Ca2+ ]i relationship at low (30 Hz) and high (120 Hz) stimulation frequencies before (control) and 30 min after induction of PLFFD, and after an additional 5 min of rest in the presence of CK-2066260 (10 μM). RESULTS Prolonged low-frequency force depression following low-intensity and high-intensity fatiguing contractions was predominantly due to decreased sarcoplasmic reticulum Ca2+ release and decreased myofibrillar Ca2+ sensitivity, respectively. CK-2066260 exposure resulted in marked increases in 30 Hz force from 52 ± 16% to 151 ± 13% and from 6 ± 4% to 98 ± 40% of controls with low-intensity and high-intensity contractions, respectively. Following repeated eccentric contractions, PLFFD was mainly due to myofibrillar dysfunction, and it was not fully reversed by CK-2066260 with 30 Hz force increasing from 48 ± 8% to 76 ± 6% of the control. CONCLUSIONS The fast skeletal muscle troponin activator CK-2066260 effectively mitigates muscle weakness, especially when it is caused by impaired activation of the myofibrillar contractile machinery due to either decreased sarcoplasmic reticulum Ca2+ release or reduced myofibrillar Ca2+ sensitivity.
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Affiliation(s)
- Arthur J Cheng
- Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden.,School of Kinesiology and Health Science, Faculty of Health, York University, Toronto, Canada
| | - Jennifer Ström
- Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden
| | - Darren T Hwee
- Research and Early Development, Cytokinetics, Inc., South San Francisco, CA, USA
| | - Fady I Malik
- Research and Early Development, Cytokinetics, Inc., South San Francisco, CA, USA
| | - Håkan Westerblad
- Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden
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17
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Aibara C, Okada N, Watanabe D, Shi J, Wada M. Effects of high-intensity interval exercise on muscle fatigue and SR function in rats: a comparison with moderate-intensity continuous exercise. J Appl Physiol (1985) 2020; 129:343-352. [DOI: 10.1152/japplphysiol.00223.2020] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Over the past decade, high-intensity interval exercise (HIIE) training has received attention as a more efficient training to improve endurance capacity. It is unclear, however, whether the extent of acute exercise-related muscle fatigue differs between HIIE and moderate-intensity continuous exercise, traditional endurance training. Here we provide evidence that restoration of force production takes a longer time after HIIE, which is ascribable to long-lasting depressions in Ca2+ release of the sarcoplasmic reticulum.
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Affiliation(s)
- Chihiro Aibara
- Graduate School of Integrated Arts and Sciences, Hiroshima University, Hiroshima, Japan
| | - Naoki Okada
- Graduate School of Integrated Arts and Sciences, Hiroshima University, Hiroshima, Japan
| | - Daiki Watanabe
- Graduate School of Humanities and Social Sciences, Hiroshima University, Hiroshima, Japan
| | - Jiayu Shi
- Graduate School of Integrated Arts and Sciences, Hiroshima University, Hiroshima, Japan
| | - Masanobu Wada
- Graduate School of Humanities and Social Sciences, Hiroshima University, Hiroshima, Japan
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18
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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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19
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Reggiani C. Caffeine as a tool to investigate sarcoplasmic reticulum and intracellular calcium dynamics in human skeletal muscles. J Muscle Res Cell Motil 2020; 42:281-289. [PMID: 32034582 DOI: 10.1007/s10974-020-09574-7] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2019] [Accepted: 01/30/2020] [Indexed: 12/23/2022]
Abstract
Caffeine is worldwide used for its power to increase cognitive and physical performance. The ergogenic effects of caffeine, however, do not depend on a direct action on muscles. Actually, the actions of caffeine on skeletal muscles, take place at millimolar concentrations which are far above the micromolar level reached after a regular consumption of coffee or similar drinks, and close to a lethal concentration. At millimolar concentrations caffeine exerts a powerful effect on sarcoplasmic reticulum (SR) activating the release of calcium via ryanodine receptors and, possibly, inhibiting calcium reuptake. For this reason caffeine has become a valuable tool for studying SR function and for diagnostics of SR related muscle disorders. This review aims to briefly describe the effects and the mechanism of action of caffeine on sarcoplasmic reticulum and to focus on its use to study intracellular calcium dynamics in human muscle fibers in physiological and pathological conditions.
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Affiliation(s)
- Carlo Reggiani
- Department of Biomedical Sciences, University of Padova, Via Marzolo 3, 35131, Padua, Italy. .,ZRS-Science and Research Center, Koper, Slovenia.
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20
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Rausch M, Böhringer D, Steinmann M, Schubert DW, Schrüfer S, Mark C, Fabry B. Measurement of Skeletal Muscle Fiber Contractility with High-Speed Traction Microscopy. Biophys J 2019; 118:657-666. [PMID: 31952805 DOI: 10.1016/j.bpj.2019.12.014] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2019] [Revised: 12/11/2019] [Accepted: 12/11/2019] [Indexed: 01/07/2023] Open
Abstract
We describe a technique for simultaneous quantification of the contractile forces and cytosolic calcium dynamics of muscle fibers embedded in three-dimensional biopolymer gels under auxotonic loading conditions. We derive a scaling law for linear elastic matrices such as basement membrane extract hydrogels (Matrigel) that allows us to measure contractile force from the shape of the relaxed and contracted muscle cell and the Young's modulus of the matrix without further knowledge of the matrix deformations surrounding the cell and without performing computationally intensive inverse force reconstruction algorithms. We apply our method to isolated mouse flexor digitorum brevis (FDB) fibers that are embedded in 10 mg/mL Matrigel. Upon electrical stimulation, individual FDB fibers show twitch forces of 0.37 ± 0.15 μN and tetanic forces (100-Hz stimulation frequency) of 2.38 ± 0.71 μN, corresponding to a tension of 0.44 ± 0.25 kPa and 2.53 ± 1.17 kPa, respectively. Contractile forces of FDB fibers increase in response to caffeine and the troponin-calcium stabilizer tirasemtiv, similar to responses measured in whole muscle. From simultaneous high-speed measurements of cell length changes and cytosolic calcium concentration using confocal line scanning at a frequency of 2048 Hz, we show that twitch and tetanic force responses to electric pulses follow the low-pass filtered calcium signal. In summary, we present a technically simple high-speed method for measuring contractile forces and cytosolic calcium dynamics of single muscle fibers. We expect that our method will help to reduce preparation time, costs, and the number of sacrificed animals needed for experiments such as drug testing.
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Affiliation(s)
- Martin Rausch
- Novartis Institutes for BioMedical Research, Basel, Switzerland.
| | - David Böhringer
- Department of Physics, Institute for Polymer Materials, Friedrich-Alexander University Erlangen-Nürnberg, Erlangen, Germany
| | | | - Dirk W Schubert
- Department of Materials Science, Institute for Polymer Materials, Friedrich-Alexander University Erlangen-Nürnberg, Erlangen, Germany
| | - Stefan Schrüfer
- Department of Materials Science, Institute for Polymer Materials, Friedrich-Alexander University Erlangen-Nürnberg, Erlangen, Germany
| | - Christoph Mark
- Department of Physics, Institute for Polymer Materials, Friedrich-Alexander University Erlangen-Nürnberg, Erlangen, Germany
| | - Ben Fabry
- Department of Physics, Institute for Polymer Materials, Friedrich-Alexander University Erlangen-Nürnberg, Erlangen, Germany
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21
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Watanabe D, Lamboley CR, Lamb GD. Effects of S-glutathionylation on the passive force-length relationship in skeletal muscle fibres of rats and humans. J Muscle Res Cell Motil 2019; 41:239-250. [PMID: 31679105 DOI: 10.1007/s10974-019-09563-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2018] [Accepted: 10/26/2019] [Indexed: 12/14/2022]
Abstract
This study investigated the effect of S-glutathionylation on passive force in skeletal muscle fibres, to determine whether activity-related redox reactions could modulate the passive force properties of muscle. Mechanically-skinned fibres were freshly obtained from human and rat muscle, setting sarcomere length (SL) by laser diffraction. Larger stretches were required to produce passive force in human fibres compared to rat fibres, but there were no fibre-type differences in either species. When fibres were exposed to glutathione disulfide (GSSG; 20 mM, 15 min) whilst stretched (at a SL where passive force reached ~ 20% of maximal Ca2+-activated force, denoted as SL20 % max), passive force was subsequently decreased at all SLs in both type I and type II fibres of rat and human (e.g., passive force at SL20 % max decreased by 12 to 25%). This decrease was fully reversed by subsequent reducing treatment with dithiothreitol (DTT; 10 mM for 10 min). If freshly skinned fibres were initially treated with DTT, there was an increase in passive force in type II fibres (by 10 ± 3% and 9 ± 2% in rat and human fibres, respectively), but not in type I fibres. These results indicate that (i) S-glutathionylation, presumably in titin, causes a decrease in passive force in skeletal muscle fibres, but the reduction is relatively smaller than that reported in cardiac muscle, (ii) in rested muscle in vivo, there appears to be some level of reversible oxidative modification, probably involving S-glutathionylation of titin, in type II fibres, but not in type I fibres.
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Affiliation(s)
- Daiki Watanabe
- Department of Physiology, Anatomy and Microbiology, La Trobe University, Melbourne, Australia. .,Graduate School of Integrated Arts and Sciences, Hiroshima University, Hiroshima, Japan.
| | - Cedric R Lamboley
- Department of Physiology, Anatomy and Microbiology, La Trobe University, Melbourne, Australia.,School of Biomedical Sciences, The University of Queensland, Brisbane, Australia
| | - Graham D Lamb
- Department of Physiology, Anatomy and Microbiology, La Trobe University, Melbourne, Australia
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22
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Nielsen J, Johnsen J, Pryds K, Ørtenblad N, Bøtker HE. Myocardial subcellular glycogen distribution and sarcoplasmic reticulum Ca 2+ handling: effects of ischaemia, reperfusion and ischaemic preconditioning. J Muscle Res Cell Motil 2019; 42:17-31. [PMID: 31630282 DOI: 10.1007/s10974-019-09557-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2019] [Accepted: 10/09/2019] [Indexed: 11/29/2022]
Abstract
Ischaemic preconditioning (IPC) protects against myocardial ischaemia-reperfusion injury. The metabolic and ionic effects of IPC remain to be clarified in detail. We aimed to investigate the effect of IPC (2 times 5 min ischaemia) on the subcellular distribution of glycogen and Ca2+-uptake and leakiness by the sarcoplasmic reticulum (SR) in response to ischaemia-reperfusion in cardiomyocytes of isolated perfused rat hearts (Wistar rats, 335 ± 25 g). As estimated by quantitative transmission electron microscopy, the pre-ischaemic contribution [%, mean (95% CI)] of three sub-fractions of glycogen relative to total glycogen was 50 (39:61) as subsarcolemmal, 41 (31:50) as intermyofibrillar, and 9 (5:13) as intramyofibrillar glycogen. After 25 min of ischaemia, the relative contribution (%) of subsarcolemmal glycogen decreased to 39 (32:47) in control hearts (Con) and to 38 (31:45) in IPC. After 15 min reperfusion the contribution of subsarcolemmal glycogen was restored to pre-ischaemic levels in IPC hearts, but not in Con hearts. IPC increased the left ventricular developed pressure following ischaemia-reperfusion compared with Con. In saponin-skinned cardiomyocyte bundles, ischaemia reduced the SR Ca2+-uptake rate, with no effect of IPC. However, IPC reduced a SR Ca2+-leakage at pre-ischaemia, after ischaemia and during reperfusion. In conclusion, subsarcolemmal glycogen was preferentially utilised during sustained myocardial ischaemia. IPC improved left ventricular function reflecting reduced ischaemia-reperfusion injury, mediated a re-distribution of glycogen towards a preferential storage within the subsarcolemmal space during reperfusion, and lowered SR Ca2+-leakage. Under the present conditions, we found no temporal associations between alterations in glycogen localisation and SR Ca2+ kinetics.
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Affiliation(s)
- Joachim Nielsen
- Department of Sports Science and Clinical Biomechanics, SDU Muscle Research Cluster (SMRC), University of Southern Denmark, 5230, Odense M, Denmark.
| | - Jacob Johnsen
- Department of Cardiology, Aarhus University Hospital, 8200, Aarhus N, Denmark
| | - Kasper Pryds
- Department of Cardiology, Aarhus University Hospital, 8200, Aarhus N, Denmark
| | - Niels Ørtenblad
- Department of Sports Science and Clinical Biomechanics, SDU Muscle Research Cluster (SMRC), University of Southern Denmark, 5230, Odense M, Denmark
| | - Hans Erik Bøtker
- Department of Cardiology, Aarhus University Hospital, 8200, Aarhus N, Denmark
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23
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Hibler EA, Zhu X, Shrubsole MJ, Hou L, Dai Q. Physical activity, dietary calcium to magnesium intake and mortality in the National Health and Examination Survey 1999-2006 cohort. Int J Cancer 2019; 146:2979-2986. [PMID: 31433866 DOI: 10.1002/ijc.32634] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2019] [Revised: 07/18/2019] [Accepted: 08/07/2019] [Indexed: 12/22/2022]
Abstract
Calcium and magnesium affect muscle mass and function. Magnesium and calcium are also important for optimal vitamin D status. Vitamin D status modifies the associations between physical activity and risk of incident cardiovascular disease (CVD) and CVD mortality. However, no study examined whether levels of magnesium and calcium and the ratio of dietary calcium to magnesium (Ca:Mg) intake modify the relationship between physical activity and mortality. We included 20,295 National Health and Nutrition Examination Survey participants (1999-2006) aged >20 years with complete dietary, physical activity and mortality data (2,663 deaths). We assessed physical activity based on public health guidelines and sex-specific tertiles of MET-minutes/week. We used Cox proportional hazards models adjusted for potential confounding factors and stratified by the intakes of magnesium, calcium, Ca:Mg ratio. We found higher physical activity was significantly associated with reduced risk of total mortality and cause-specific mortality, regardless of Ca:Mg ratio, magnesium or calcium intake. In contrast, both moderate and high physical activity were significantly associated with substantially reduced risks of mortality due to cancer when magnesium intake was above the RDA level. We also found higher physical activity was significantly associated with a reduced risk of mortality due to cancer only when Ca:Mg ratios were between 1.7 and 2.6, although the interaction was not significant. Overall, dietary magnesium and, potentially, the Ca:Mg ratio modify the relationship between physical activity and cause-specific mortality. Further study is important to understand the modifying effects of the balance between calcium and magnesium intake on physical activity for chronic disease prevention.
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Affiliation(s)
- Elizabeth A Hibler
- Division of Epidemiology, Department of Medicine, Vanderbilt-Ingram Cancer Center, Vanderbilt University School of Medicine, Nashville, TN.,Division of Cancer Prevention and Control, Department of Preventive Medicine, Feinberg School of Medicine, Northwestern University, Chicago, IL
| | - Xiangzhu Zhu
- Division of Epidemiology, Department of Medicine, Vanderbilt-Ingram Cancer Center, Vanderbilt University School of Medicine, Nashville, TN
| | - Martha J Shrubsole
- Division of Epidemiology, Department of Medicine, Vanderbilt-Ingram Cancer Center, Vanderbilt University School of Medicine, Nashville, TN
| | - Lifang Hou
- Division of Cancer Prevention and Control, Department of Preventive Medicine, Feinberg School of Medicine, Northwestern University, Chicago, IL
| | - Qi Dai
- Division of Epidemiology, Department of Medicine, Vanderbilt-Ingram Cancer Center, Vanderbilt University School of Medicine, Nashville, TN
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24
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Hill C, James RS, Cox VM, Tallis J. The Effect of Increasing Age on the Concentric and Eccentric Contractile Properties of Isolated Mouse Soleus and Extensor Digitorum Longus Muscles. J Gerontol A Biol Sci Med Sci 2019; 73:579-587. [PMID: 29236945 DOI: 10.1093/gerona/glx243] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2017] [Accepted: 12/06/2017] [Indexed: 11/13/2022] Open
Abstract
There is currently a limited amount of literature investigating the age-related changes in eccentric muscle function in vitro. The present study uniquely uses the work loop (WL) technique, to better replicate in vivo muscle function, in the assessment of the age- and muscle-specific changes in acute and sustained concentric and eccentric power and recovery. Whole soleus or extensor digitorum longus (EDL) muscles were isolated from 10-week and 78-week-old mice and acute and sustained concentric and eccentric WL power assessed. Despite an age-related increase in body and muscle mass, peak absolute power for both muscles was unaffected by age. Peak concentric power normalized to muscle mass declined significantly for each muscle, while peak normalized eccentric power declined only for soleus. Fatigue resistance and recovery for the soleus did not differ between age or contraction type. Older EDL was less resistant to concentric fatigue, but was better able to withstand sustained eccentric activity than young EDL. We have shown that age-related changes in muscle quality are more limited for eccentric function than concentric function. A greater bodily inertia is likely to further reduce in vivo locomotor performance in older animals.
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Affiliation(s)
- Cameron Hill
- School of Life Sciences, Coventry University, UK
| | - Rob S James
- School of Life Sciences, Coventry University, UK
| | - Val M Cox
- School of Life Sciences, Coventry University, UK
| | - Jason Tallis
- School of Life Sciences, Coventry University, UK
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25
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Christiansen D, MacInnis MJ, Zacharewicz E, Xu H, Frankish BP, Murphy RM. A fast, reliable and sample-sparing method to identify fibre types of single muscle fibres. Sci Rep 2019; 9:6473. [PMID: 31019216 PMCID: PMC6482153 DOI: 10.1038/s41598-019-42168-z] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2018] [Accepted: 03/08/2019] [Indexed: 11/30/2022] Open
Abstract
Many skeletal muscle proteins are present in a cell-specific or fibre-type dependent manner. Stimuli such as exercise, aging, and disease have been reported to result in fibre-specific responses in protein abundances. Thus, fibre-type-specific determination of the content of specific proteins provides enhanced mechanistic understanding of muscle physiology and biochemistry compared with typically performed whole-muscle homogenate analyses. This analysis, however, is laborious and typically not performed. We present a novel dot blotting method for easy and rapid determination of skeletal muscle fibre type based on myosin heavy chain (MHC) isoform presence. Requiring only small amounts of starting muscle tissue (i.e., 2–10 mg wet weight), muscle fibre type is determined in one-tenth of a 1–3-mm fibre segment, with the remainder of each segment pooled with fibre segments of the same type (I or II) for subsequent protein quantification by western blotting. This method, which we validated using standard western blotting, is much simpler and cheaper than previous methods and is adaptable for laboratories routinely performing biochemical analyses. Use of dot blotting for fibre typing will facilitate investigations of fibre-specific responses to diverse stimuli, which will advance our understanding of skeletal muscle physiology and biochemistry.
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Affiliation(s)
- Danny Christiansen
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, Victoria, 3086, Australia.,Institute for Health and Sport (IHES), Victoria University, Melbourne, Australia
| | - Martin J MacInnis
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, Victoria, 3086, Australia.,Faculty of Kinesiology, University of Calgary, Calgary, Canada
| | - Evelyn Zacharewicz
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, Victoria, 3086, Australia
| | - Hongyang Xu
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, Victoria, 3086, Australia
| | - Barnaby P Frankish
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, Victoria, 3086, Australia
| | - Robyn M Murphy
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, Victoria, 3086, Australia.
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26
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Zügel M, Wehrstein F, Qiu S, Diel P, Steinacker JM, Schumann U. Moderate intensity continuous training reverses the detrimental effects of ovariectomy on RyR1 phosphorylation in rat skeletal muscle. Mol Cell Endocrinol 2019; 481:1-7. [PMID: 30465874 DOI: 10.1016/j.mce.2018.11.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/13/2018] [Revised: 10/12/2018] [Accepted: 11/12/2018] [Indexed: 10/27/2022]
Abstract
High 17β-Estradiol (E2) concentrations in isolated ventricular myocytes as well as a lack of ovarian hormones in cardiac muscle of ovariectomized (OVX) rodents has been shown to lead to arrhythmogenic effects by inducing post-translational modifications, including phosphorylation of the sarcoplasmic reticulum (SR) Ca2+ release channel ryanodine receptor-2 (RyR2). The effects of estrogens on the phosphorylation status of the RyR1 in skeletal muscle have not been investigated before. Furthermore, while high intensity exercise has been shown to increase RyR phosphorylation, there is no data on the effects of moderate intensity continuous training (MICT). The aims of the study were to investigate the effects of a 3-day treatment with low (1 nM, moderate (5 nM) and high (10 nM, 100 nM) E2 concentrations on RyR1 mRNA and protein expression and phosphorylation status (pRyRSer2844) in cultured C2C12 myotubes and to study the effects of OVX on RyR1 expression and phosphorylation in rat skeletal muscle in combination with 3 weeks of MICT. Treatment with low, physiological E2 concentrations reduced dihydropyridine receptor (DHPR) and RyR1 mRNA content in C2C12 myotubes compared to untreated control cells, whereas RyR1 protein phosphorylation (pRyRSer2844) was significantly increased after treatment with high, non-physiological E2 concentrations (p ≤ 0.05). RyR1 protein content (p ≤ 0.05) and pRyRSer2844 (p ≤ 0.05) were significantly elevated in skeletal muscle of OVX vs. sham-operated rats. Importantly, pRyRSer2844 levels were similar to sham-operated controls in OVX rats after MICT (OVX vs. OVX + MICT, p ≤ 0.05). Our results indicate, that one of the actions of estrogens is to alter skeletal muscle Ca2+ homeostasis by modulating the expression and phosphorylation of the RyR1 in skeletal muscle. Notably, regular MICT was able to counteract RyR1 phosphorylation in skeletal muscle of OVX rats.
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Affiliation(s)
- M Zügel
- Department of Internal Medicine, Division of Sports Medicine, Ulm University, Ulm, Germany.
| | - F Wehrstein
- Department of Internal Medicine, Division of Sports Medicine, Ulm University, Ulm, Germany
| | - S Qiu
- Department of Endocrinology, Zhongda Hospital, Institute of Diabetes, Nanjing, China
| | - P Diel
- Department of Sports Medicine, Molecular and Cellular Sports Medicine, German Sports University Cologne, Germany
| | - J M Steinacker
- Department of Internal Medicine, Division of Sports Medicine, Ulm University, Ulm, Germany
| | - U Schumann
- Department of Internal Medicine, Division of Sports Medicine, Ulm University, Ulm, Germany
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27
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Changes in Redox Signaling in the Skeletal Muscle with Aging. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2019; 2019:4617801. [PMID: 30800208 PMCID: PMC6360032 DOI: 10.1155/2019/4617801] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/22/2018] [Revised: 11/05/2018] [Accepted: 11/22/2018] [Indexed: 01/01/2023]
Abstract
Reduction in muscle strength with aging is due to both loss of muscle mass (quantity) and intrinsic force production (quality). Along with decreased functional capacity of the muscle, age-related muscle loss is associated with corresponding comorbidities and healthcare costs. Mitochondrial dysfunction and increased oxidative stress are the central driving forces for age-related skeletal muscle abnormalities. The increased oxidative stress in the aged muscle can lead to altered excitation-contraction coupling and calcium homeostasis. Furthermore, apoptosis-mediated fiber loss, atrophy of the remaining fibers, dysfunction of the satellite cells (muscle stem cells), and concomitant impaired muscle regeneration are also the consequences of increased oxidative stress, leading to a decrease in muscle mass, strength, and function of the aged muscle. Here we summarize the possible effects of oxidative stress in the aged muscle and the benefits of physical activity and antioxidant therapy.
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28
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Sundberg CW, Hunter SK, Trappe SW, Smith CS, Fitts RH. Effects of elevated H + and P i on the contractile mechanics of skeletal muscle fibres from young and old men: implications for muscle fatigue in humans. J Physiol 2018; 596:3993-4015. [PMID: 29806714 PMCID: PMC6117549 DOI: 10.1113/jp276018] [Citation(s) in RCA: 42] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2018] [Accepted: 04/27/2018] [Indexed: 01/09/2023] Open
Abstract
KEY POINTS The mechanisms responsible for the loss in muscle power and increased fatigability with ageing are unresolved. We show that the contractile mechanics of fibres from the vastus lateralis of old men were well-preserved compared to those of young men, but the selective loss of fast myosin heavy chain II muscle was strongly associated with age-related decrements in whole-muscle strength and power. We reveal that the combination of acidosis (H+ ) and inorganic phosphate (Pi ) is an important mediator of muscle fatigue in humans by inhibiting the low- to high-force state of the cross-bridge cycle and peak power, but the depressive effects of these ions on cross-bridge function were similar in fibres from young and old men. These findings suggest that the age-related loss in muscle power is primarily determined by the atrophy of fast fibres, but the age-related increased fatigability cannot be explained by an increased sensitivity of the cross-bridge to H+ and Pi . ABSTRACT The present study aimed to identify the mechanisms responsible for the loss in muscle power and increased fatigability with ageing by integrating measures of whole-muscle function with single fibre contractile mechanics. After adjusting for the 22% smaller muscle mass in old (73-89 years, n = 6) compared to young men (20-29 years, n = 6), isometric torque and power output of the knee extensors were, respectively, 38% and 53% lower with age. Fatigability was ∼2.7-fold greater with age and strongly associated with reductions in the electrically-evoked contractile properties. To test whether cross-bridge mechanisms could explain age-related decrements in knee extensor function, we exposed myofibres (n = 254) from the vastus lateralis to conditions mimicking quiescent muscle and fatiguing levels of acidosis (H+ ) (pH 6.2) and inorganic phosphate (Pi ) (30 mm). The fatigue-mimicking condition caused marked reductions in force, shortening velocity and power and inhibited the low- to high-force state of the cross-bridge cycle, confirming findings from non-human studies that these ions act synergistically to impair cross-bridge function. Other than severe age-related atrophy of fast fibres (-55%), contractile function and the depressive effects of the fatigue-mimicking condition did not differ in fibres from young and old men. The selective loss of fast myosin heavy chain II muscle was strongly associated with the age-related decrease in isometric torque (r = 0.785) and power (r = 0.861). These data suggest that the age-related loss in muscle strength and power are primarily determined by the atrophy of fast fibres, but the age-related increased fatigability cannot be explained by an increased sensitivity of the cross-bridge to H+ and Pi .
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Affiliation(s)
- Christopher W. Sundberg
- Exercise Science ProgramMilwaukeeWIUSA
- Clinical & Translational Rehabilitation Health Sciences ProgramDepartment of Physical TherapyMarquette UniversityMilwaukeeWIUSA
| | - Sandra K. Hunter
- Exercise Science ProgramMilwaukeeWIUSA
- Clinical & Translational Rehabilitation Health Sciences ProgramDepartment of Physical TherapyMarquette UniversityMilwaukeeWIUSA
| | - Scott W. Trappe
- Human Performance LaboratoryBall State UniversityMuncieINUSA
| | | | - Robert H. Fitts
- Department of Biological SciencesMarquette UniversityMilwaukeeWIUSA
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29
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Jacko D, Bersiner K, Friederichs G, Ritter P, Nirenberg L, Eisenbraun J, de Marées M, Bloch W, Gehlert S. Resistance exercise-induced muscle fatigue is not accompanied by increased phosphorylation of ryanodine receptor 1 at serine 2843. PLoS One 2018; 13:e0199307. [PMID: 29953482 PMCID: PMC6023196 DOI: 10.1371/journal.pone.0199307] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2017] [Accepted: 06/05/2018] [Indexed: 12/20/2022] Open
Abstract
Skeletal muscle fatigue has been shown to be associated with hyperphosphorylation of the ryanodine receptor 1 at serine 2843 (pRyR1Ser2843), due to chronic overloading exercise. We investigated whether pRyR1Ser2843, is a mechanism relevant for muscle fatigue also under acute, in contrast to chronic, muscle loading. 24 male subjects (age: 24,8±3,8; height: 182,8±7,2 cm; weight: 82,5±9,9 kg) were evenly (n = 6) assigned to the following four different resistance exercise (RE) groups: hypertrophy- (HYP), strength endurance- (SE), maximum power- (MAX) at the subjects' 10, 25 and 3 repetition maximum, respectively, and low intensity (LI) RE with 70% of the 10 repetition maximum. Each group completed three different RE volumes (1 set, 5, and 10 sets). Muscle biopsies from the vastus lateralis were taken before and after exercise, analyzed for pRyR1Ser2843 and examined for association with RE-induced muscle fatigue which was determined as reduction in maximum isometric force (isoFmax) in the quadriceps femoris muscle also before and after exercise.The degree of RE-induced muscle fatigue was specific in terms of set volume as well as of RE mode. isoFmax was not reduced in any group after one set of RE. Five sets led to a significant reduction of isoFmax in HYP and SE but not in LI and MAX (p<0,05). Ten sets of RE, as compared to five sets, exclusively induced further muscle fatigue in LI. In terms of RE mode differences, isoFmax reduction was generally higher in HYP and SE than in MAX and Li after five and ten sets of RE (p<0,05). However, pRyR1Ser2843 did not show any significant regulation, regardless of exercise condition. We conclude that despite its relevance in reducing muscle contractility in chronic overloading, pRyR1Ser2843 does not reflect the degree of muscle fatigue exerted by acute hypertrophy-, strength endurance-, maximum power and low intensity-oriented exercise.
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Affiliation(s)
- Daniel Jacko
- Section of Molecular and Cellular Sport Medicine, Institute of Cardiovascular Research and Sport Medicine, German Sport University Cologne, Cologne, Germany
- Olympic Base Center Rhineland, Cologne, Germany
- * E-mail:
| | - Käthe Bersiner
- Institute of Sport Science, University of Hildesheim, Hildesheim, Germany
| | - Gerrit Friederichs
- Section of Molecular and Cellular Sport Medicine, Institute of Cardiovascular Research and Sport Medicine, German Sport University Cologne, Cologne, Germany
| | - Patrick Ritter
- Section of Molecular and Cellular Sport Medicine, Institute of Cardiovascular Research and Sport Medicine, German Sport University Cologne, Cologne, Germany
| | - Linnea Nirenberg
- Section of Molecular and Cellular Sport Medicine, Institute of Cardiovascular Research and Sport Medicine, German Sport University Cologne, Cologne, Germany
| | - Jan Eisenbraun
- Section of Molecular and Cellular Sport Medicine, Institute of Cardiovascular Research and Sport Medicine, German Sport University Cologne, Cologne, Germany
| | - Markus de Marées
- Section of Sports Medicine and Sports Nutrition, Faculty of Sport Science, Ruhr University of Bochum, Bochum, Germany
| | - Wilhelm Bloch
- Section of Molecular and Cellular Sport Medicine, Institute of Cardiovascular Research and Sport Medicine, German Sport University Cologne, Cologne, Germany
| | - Sebastian Gehlert
- Section of Molecular and Cellular Sport Medicine, Institute of Cardiovascular Research and Sport Medicine, German Sport University Cologne, Cologne, Germany
- Institute of Sport Science, University of Hildesheim, Hildesheim, Germany
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30
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Koenig X, Choi RH, Launikonis BS. Store-operated Ca 2+ entry is activated by every action potential in skeletal muscle. Commun Biol 2018; 1:31. [PMID: 30271917 PMCID: PMC6123720 DOI: 10.1038/s42003-018-0033-7] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2018] [Accepted: 03/12/2018] [Indexed: 02/06/2023] Open
Abstract
Store-operated calcium (Ca2+) entry (SOCE) in skeletal muscle is rapidly activated across the tubular system during direct activation of Ca2+ release. The tubular system is the invagination of the plasma membrane that forms junctions with the sarcoplasmic reticulum (SR) where STIM1, Orai1 and ryanodine receptors are found. The physiological activation of SOCE in muscle is not defined, thus clouding its physiological role. Here we show that the magnitude of a phasic tubular system Ca2+ influx is dependent on SR Ca2+ depletion magnitude, and define this as SOCE. Consistent with SOCE, the influx was resistant to nifedipine and BayK8644, and silenced by inhibition of SR Ca2+ release during excitation. The SOCE transient was shaped by action potential frequency and SR Ca2+ pump activity. Our results show that SOCE in skeletal muscle acts as an immediate counter-flux to Ca2+ loss across the tubular system during excitation-contraction coupling. Xaver Koenig et al. demonstrate the physiological activation of store-operated calcium entry in muscle, pointing to a role for this mechanism. The resulting influx of calcium into the cytoplasm is shaped by action potential frequency and calcium pump activity.
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Affiliation(s)
- Xaver Koenig
- School of Biomedical Sciences, The University of Queensland, Brisbane, QLD, 4072, Australia.,Center for Physiology and Pharmacology, Medical University of Vienna, Schwarzspanierstrasse 17, 1090, Wien, Austria
| | - Rocky H Choi
- 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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31
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Sundberg CW, Kuplic A, Hassanlouei H, Hunter SK. Mechanisms for the age-related increase in fatigability of the knee extensors in old and very old adults. J Appl Physiol (1985) 2018; 125:146-158. [PMID: 29494293 DOI: 10.1152/japplphysiol.01141.2017] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
The mechanisms for the age-related increase in fatigability during high-velocity contractions in old and very old adults (≥80 yr) are unresolved. Moreover, whether the increased fatigability with advancing age and the underlying mechanisms differ between men and women is not known. The purpose of this study was to quantify the fatigability of knee extensor muscles and identify the mechanisms of fatigue in 30 young (22.6 ± 0.4 yr; 15 men), 62 old (70.5 ± 0.7 yr; 33 men), and 12 very old (86.0 ± 1.3 yr; 6 men) men and women elicited by high-velocity concentric contractions. Participants performed 80 maximal velocity contractions (1 contraction per 3 s) with a load equivalent to 20% of the maximum voluntary isometric contraction. Voluntary activation and contractile properties were quantified before and immediately following exercise (<10 s) using transcranial magnetic stimulation and electrical stimulation. Absolute mechanical power output was 97 and 217% higher in the young compared with old and very old adults, respectively. Fatigability (reductions in power) progressively increased across age groups, with a power loss of 17% in young, 31% in old, and 44% in very old adults. There were no sex differences in fatigability among any of the age groups. The age-related increase in power loss was strongly associated with changes in the involuntary twitch amplitude ( r = 0.75, P < 0.001). These data suggest that the age-related increased power loss during high-velocity fatiguing exercise is unaffected by biological sex and determined primarily by mechanisms that disrupt excitation contraction coupling and/or cross-bridge function. NEW & NOTEWORTHY We show that aging of the neuromuscular system results in an increase in fatigability of the knee extensors during high-velocity exercise that is more pronounced in very old adults (≥80 yr) and occurs similarly in men and women. Importantly, the age-related increase in power loss was strongly associated with the changes in the electrically evoked contractile properties suggesting that the increased fatigability with aging is determined primarily by mechanisms within the muscle for both sexes.
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Affiliation(s)
- Christopher W Sundberg
- Exercise Science Program, Department of Physical Therapy, Marquette University , Milwaukee, Wisconsin.,Clinical and Translational Rehabilitation Health Sciences Program, Department of Physical Therapy, Marquette University , Milwaukee, Wisconsin
| | - Andrew Kuplic
- Exercise Science Program, Department of Physical Therapy, Marquette University , Milwaukee, Wisconsin.,Clinical and Translational Rehabilitation Health Sciences Program, Department of Physical Therapy, Marquette University , Milwaukee, Wisconsin
| | - Hamidollah Hassanlouei
- Exercise Science Program, Department of Physical Therapy, Marquette University , Milwaukee, Wisconsin
| | - Sandra K Hunter
- Exercise Science Program, Department of Physical Therapy, Marquette University , Milwaukee, Wisconsin.,Clinical and Translational Rehabilitation Health Sciences Program, Department of Physical Therapy, Marquette University , Milwaukee, Wisconsin
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32
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Lamboley CR, Xu H, Dutka TL, Hanson ED, Hayes A, Violet JA, Murphy RM, Lamb GD. Effect of androgen deprivation therapy on the contractile properties of type I and type II skeletal muscle fibres in men with non-metastatic prostate cancer. Clin Exp Pharmacol Physiol 2017; 45:146-154. [DOI: 10.1111/1440-1681.12873] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2017] [Revised: 08/30/2017] [Accepted: 09/28/2017] [Indexed: 11/30/2022]
Affiliation(s)
- Cedric R Lamboley
- Institute of Sport, Exercise and Active Living (ISEAL); College of Sport and Exercise Science; Victoria University; Melbourne Vic. Australia
- School of Life Sciences; La Trobe University; Melbourne Vic. Australia
| | - Hongyang Xu
- Department of Biochemistry and Genetics; La Trobe Institute for Molecular Science; La Trobe University; Melbourne Vic. Australia
| | - Travis L Dutka
- School of Life Sciences; La Trobe University; Melbourne Vic. Australia
| | - Erik D Hanson
- Institute of Sport, Exercise and Active Living (ISEAL); College of Sport and Exercise Science; Victoria University; Melbourne Vic. Australia
- Australian Institute for Musculoskeletal Science (AIMSS); Sunshine Hospital; Western Health; Melbourne Vic. Australia
- College of Health and Biomedicine; Victoria University; Melbourne Vic. Australia
| | - Alan Hayes
- Institute of Sport, Exercise and Active Living (ISEAL); College of Sport and Exercise Science; Victoria University; Melbourne Vic. Australia
- Australian Institute for Musculoskeletal Science (AIMSS); Sunshine Hospital; Western Health; Melbourne Vic. Australia
- College of Health and Biomedicine; Victoria University; Melbourne Vic. Australia
| | - John A Violet
- Division of Radiation Oncology and Cancer Imaging; Peter MacCallum Cancer Centre; East Melbourne Vic. Australia
| | - Robyn M Murphy
- Department of Biochemistry and Genetics; La Trobe Institute for Molecular Science; La Trobe University; Melbourne Vic. Australia
| | - Graham D Lamb
- School of Life Sciences; La Trobe University; Melbourne Vic. Australia
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Baumann CW, Kwak D, Liu HM, Thompson LV. Age-induced oxidative stress: how does it influence skeletal muscle quantity and quality? J Appl Physiol (1985) 2016; 121:1047-1052. [PMID: 27197856 PMCID: PMC5142250 DOI: 10.1152/japplphysiol.00321.2016] [Citation(s) in RCA: 110] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2016] [Accepted: 05/12/2016] [Indexed: 12/25/2022] Open
Abstract
With advancing age, skeletal muscle function declines as a result of strength loss. These strength deficits are largely due to reductions in muscle size (i.e., quantity) and its intrinsic force-producing capacity (i.e., quality). Age-induced reductions in skeletal muscle quantity and quality can be the consequence of several factors, including accumulation of reactive oxygen and nitrogen species (ROS/RNS), also known as oxidative stress. Therefore, the purpose of this mini-review is to highlight the published literature that has demonstrated links between aging, oxidative stress, and skeletal muscle quantity or quality. In particular, we focused on how oxidative stress has the potential to reduce muscle quantity by shifting protein balance in a deficit, and muscle quality by impairing activation at the neuromuscular junction, excitation-contraction (EC) coupling at the ryanodine receptor (RyR), and cross-bridge cycling within the myofibrillar apparatus. Of these, muscle weakness due to EC coupling failure mediated by RyR dysfunction via oxidation and/or nitrosylation appears to be the strongest candidate based on the publications reviewed. However, it is clear that age-associated oxidative stress has the ability to alter strength through several mechanisms and at various locations of the muscle fiber.
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Affiliation(s)
- Cory W Baumann
- Department of Physical Medicine and Rehabilitation, University of Minnesota Medical School, Minneapolis, Minnesota
| | - Dongmin Kwak
- Department of Physical Medicine and Rehabilitation, University of Minnesota Medical School, Minneapolis, Minnesota
| | - Haiming M Liu
- Department of Physical Medicine and Rehabilitation, University of Minnesota Medical School, Minneapolis, Minnesota
| | - LaDora V Thompson
- Department of Physical Medicine and Rehabilitation, University of Minnesota Medical School, Minneapolis, Minnesota
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Mitochondria in the Aging Muscles of Flies and Mice: New Perspectives for Old Characters. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2016; 2016:9057593. [PMID: 27630760 PMCID: PMC5007348 DOI: 10.1155/2016/9057593] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/29/2016] [Revised: 03/30/2016] [Accepted: 05/16/2016] [Indexed: 12/22/2022]
Abstract
Sarcopenia is the loss of muscle mass accompanied by a decrease in muscle strength and resistance and is the main cause of disability among the elderly. Muscle loss begins long before there is any clear physical impact in the senior adult. Despite all this, the molecular mechanisms underlying muscle aging are far from being understood. Recent studies have identified that not only mitochondrial metabolic dysfunction but also mitochondrial dynamics and mitochondrial calcium uptake could be involved in the degeneration of skeletal muscle mass. Mitochondrial homeostasis influences muscle quality which, in turn, could play a triggering role in signaling of systemic aging. Thus, it has become apparent that mitochondrial status in muscle cells could be a driver of whole body physiology and organismal aging. In the present review, we discuss the existing evidence for the mitochondria related mechanisms underlying the appearance of muscle aging and sarcopenia in flies and mice.
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Lamboley CR, Wyckelsma VL, Perry BD, McKenna MJ, Lamb GD. Effect of 23-day muscle disuse on sarcoplasmic reticulum Ca2+ properties and contractility in human type I and type II skeletal muscle fibers. J Appl Physiol (1985) 2016; 121:483-92. [DOI: 10.1152/japplphysiol.00337.2016] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2016] [Accepted: 06/28/2016] [Indexed: 11/22/2022] Open
Abstract
Inactivity negatively impacts on skeletal muscle function mainly through muscle atrophy. However, recent evidence suggests that the quality of individual muscle fibers is also altered. This study examined the effects of 23 days of unilateral lower limb suspension (ULLS) on specific force and sarcoplasmic reticulum (SR) Ca2+ content in individual skinned muscle fibers. Muscle biopsies of the vastus lateralis were taken from six young healthy adults prior to and following ULLS. After disuse, the endogenous SR Ca2+ content was ∼8% lower in type I fibers and maximal SR Ca2+ capacity was lower in both type I and type II fibers (−11 and −5%, respectively). The specific force, measured in single skinned fibers from three subjects, decreased significantly after ULLS in type II fibers (−23%) but not in type I fibers (−9%). Western blot analyses showed no significant change in the amounts of myosin heavy chain (MHC) I and MHC IIa following the disuse, whereas the amounts of sarco(endo)plasmic reticulum Ca2+-ATPase 1 (SERCA1) and calsequestrin increased by ∼120 and ∼20%, respectively, and the amount of troponin I decreased by ∼21%. These findings suggest that the decline in force and power occurring with muscle disuse is likely to be exacerbated in part by reductions in maximum specific force in type II fibers, and in the amount of releasable SR Ca2+ in both fiber types, the latter not being attributable to a reduced calsequestrin level. Furthermore, the ∼3-wk disuse in human elicits change in SR properties, in particular a more than twofold upregulation in SERCA1 density, before any fiber-type shift.
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Affiliation(s)
- C. R. Lamboley
- Institute of Sport, Exercise and Active Living, Victoria University, Melbourne, Victoria, Australia
- School of Life Sciences, La Trobe University, Melbourne, Victoria, Australia
| | - V. L. Wyckelsma
- Institute of Sport, Exercise and Active Living, Victoria University, Melbourne, Victoria, Australia
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, Victoria, Australia; and
| | - B. D. Perry
- Institute of Sport, Exercise and Active Living, Victoria University, Melbourne, Victoria, Australia
- Renal Division, Department of Medicine, Emory University, Atlanta, Georgia
| | - M. J. McKenna
- Institute of Sport, Exercise and Active Living, Victoria University, Melbourne, Victoria, Australia
| | - G. D. Lamb
- School of Life Sciences, La Trobe University, Melbourne, Victoria, Australia
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