1
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Göransson S, Strömblad S. Regulation of protein synthesis and stability by mechanical cues and its implications in cancer. Curr Opin Cell Biol 2024; 86:102304. [PMID: 38113713 DOI: 10.1016/j.ceb.2023.102304] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2023] [Revised: 11/07/2023] [Accepted: 11/26/2023] [Indexed: 12/21/2023]
Abstract
Elevated tissue stiffness is a common feature of many solid tumors and the downstream mechanical signaling affects many cellular processes and contributes to cancer progression. Significant progress has been made in understanding how the mechanical properties of the matrix affect cancer cell behavior as well as transcription. However, how the same mechanical cues impact protein synthesis and stability and how this may contribute to disease is less well understood. Here, we present emerging evidence that cancer progression is frequently supported by gene regulation acting beyond the mRNA level and highlight some of the known crosstalk between this type of regulation and mechanotransduction in cancer as well as in other contexts. We suggest that future systematic approaches to define mechanosensitive translatomes and proteomes and how these are controlled may provide novel targets for cancer therapy.
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Affiliation(s)
- Sara Göransson
- Department of Biosciences and Nutrition, Karolinska Institutet, SE-141 83 Huddinge, Sweden
| | - Staffan Strömblad
- Department of Biosciences and Nutrition, Karolinska Institutet, SE-141 83 Huddinge, Sweden.
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2
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Roberts MD, McCarthy JJ, Hornberger TA, Phillips SM, Mackey AL, Nader GA, Boppart MD, Kavazis AN, Reidy PT, Ogasawara R, Libardi CA, Ugrinowitsch C, Booth FW, Esser KA. Mechanisms of mechanical overload-induced skeletal muscle hypertrophy: current understanding and future directions. Physiol Rev 2023; 103:2679-2757. [PMID: 37382939 PMCID: PMC10625844 DOI: 10.1152/physrev.00039.2022] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2023] [Revised: 06/12/2023] [Accepted: 06/21/2023] [Indexed: 06/30/2023] Open
Abstract
Mechanisms underlying mechanical overload-induced skeletal muscle hypertrophy have been extensively researched since the landmark report by Morpurgo (1897) of "work-induced hypertrophy" in dogs that were treadmill trained. Much of the preclinical rodent and human resistance training research to date supports that involved mechanisms include enhanced mammalian/mechanistic target of rapamycin complex 1 (mTORC1) signaling, an expansion in translational capacity through ribosome biogenesis, increased satellite cell abundance and myonuclear accretion, and postexercise elevations in muscle protein synthesis rates. However, several lines of past and emerging evidence suggest that additional mechanisms that feed into or are independent of these processes are also involved. This review first provides a historical account of how mechanistic research into skeletal muscle hypertrophy has progressed. A comprehensive list of mechanisms associated with skeletal muscle hypertrophy is then outlined, and areas of disagreement involving these mechanisms are presented. Finally, future research directions involving many of the discussed mechanisms are proposed.
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Affiliation(s)
- Michael D Roberts
- School of Kinesiology, Auburn University, Auburn, Alabama, United States
| | - John J McCarthy
- Department of Physiology, College of Medicine, University of Kentucky, Lexington, Kentucky, United States
| | - Troy A Hornberger
- Department of Comparative Biosciences, University of Wisconsin-Madison, Madison, Wisconsin, United States
| | - Stuart M Phillips
- Department of Kinesiology, McMaster University, Hamilton, Ontario, Canada
| | - Abigail L Mackey
- Institute of Sports Medicine Copenhagen, Department of Orthopedic Surgery, Copenhagen University Hospital-Bispebjerg and Frederiksberg, and Department of Clinical Medicine, University of Copenhagen, Copenhagen, Denmark
| | - Gustavo A Nader
- Department of Kinesiology and Huck Institutes of the Life Sciences, The Pennsylvania State University, University Park, Pennsylvania, United States
| | - Marni D Boppart
- Department of Kinesiology and Community Health, University of Illinois at Urbana-Champaign, Urbana, Illinois, United States
| | - Andreas N Kavazis
- School of Kinesiology, Auburn University, Auburn, Alabama, United States
| | - Paul T Reidy
- Department of Kinesiology, Nutrition and Health, Miami University, Oxford, Ohio, United States
| | - Riki Ogasawara
- Healthy Food Science Research Group, Cellular and Molecular Biotechnology Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Japan
| | - Cleiton A Libardi
- MUSCULAB-Laboratory of Neuromuscular Adaptations to Resistance Training, Department of Physical Education, Federal University of São Carlos, São Carlos, Brazil
| | - Carlos Ugrinowitsch
- School of Physical Education and Sport, University of São Paulo, São Paulo, Brazil
| | - Frank W Booth
- Department of Biomedical Sciences, University of Missouri, Columbia, Missouri, United States
| | - Karyn A Esser
- Department of Physiology and Aging, College of Medicine, University of Florida, Gainesville, Florida, United States
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3
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Chaillou T, Montiel-Rojas D. Does the blunted stimulation of skeletal muscle protein synthesis by aging in response to mechanical load result from impaired ribosome biogenesis? FRONTIERS IN AGING 2023; 4:1171850. [PMID: 37256189 PMCID: PMC10225510 DOI: 10.3389/fragi.2023.1171850] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/22/2023] [Accepted: 05/04/2023] [Indexed: 06/01/2023]
Abstract
Age-related loss of skeletal muscle mass leads to a reduction of strength. It is likely due to an inadequate stimulation of muscle protein synthesis (MPS) in response to anabolic stimuli, such as mechanical load. Ribosome biogenesis is a major determinant of translational capacity and is essential for the control of muscle mass. This mini-review aims to put forth the hypothesis that ribosome biogenesis is impaired by aging in response to mechanical load, which could contribute to the age-related anabolic resistance and progressive muscle atrophy. Recent animal studies indicate that aging impedes muscle hypertrophic response to mechanical overload. This is associated with an impaired transcription of ribosomal DNA (rDNA) by RNA polymerase I (Pol I), a limited increase in total RNA concentration, a blunted activation of AKT/mTOR pathway, and an increased phosphorylation of AMPK. In contrast, an age-mediated impairment of ribosome biogenesis is unlikely in response to electrical stimulations. In human, the hypertrophic response to resistance exercise training is diminished with age. This is accompanied by a deficit in long-term MPS and an absence of increased total RNA concentration. The results addressing the acute response to resistance exercise suggest an impaired Pol I-mediated rDNA transcription and attenuated activation/expression of several upstream regulators of ribosome biogenesis in muscles from aged individuals. Altogether, emerging evidence indicates that impaired ribosome biogenesis could partly explain age-related anabolic resistance to mechanical load, which may ultimately contribute to progressive muscle atrophy. Future research should develop more advanced molecular tools to provide in-depth analysis of muscle ribosome biogenesis.
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4
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Lee CJ, Nicoll JX. Time Course Evaluation of Mitogen-Activated Protein Kinase Phosphorylation to Resistance Exercise: A Systematic Review. J Strength Cond Res 2023; 37:710-725. [PMID: 36727997 DOI: 10.1519/jsc.0000000000004409] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
ABSTRACT Lee, CJ and Nicoll, JX. Time course evaluation of mitogen-activated protein kinase phosphorylation to resistance exercise: a systematic review. J Strength Cond Res 37(3): 710-725, 2023-Resistance exercise (RE) can increase the signaling activities of mitogen-activated protein kinases (MAPKs), specifically extracellular signal-regulated kinases 1/2 (ERK1/2), p90 ribosomal S6 kinases (p90RSK), c-Jun NH2-terminal kinases (JNK), and p38-MAPK. These RE-induced responses contribute to various intracellular processes modulating growth and development in skeletal muscles, playing an essential role in resistance training adaptations. The time course of MAPK phosphorylation to different RE conditions, such as training experience and varying loads, remains ambiguous. A systematic review was conducted to determine the effects of different post-RE recovery time points on the MAPK signaling cascade. In addition, the effects of loading and training statuses on MAPK responses were also investigated. The review was performed according to the preferred reporting items for systematic reviews and meta-analyses guidelines with a literature search incorporating 3 electronic databases. A modified version of the Downs and Black checklist was used to evaluate the methodological quality of the studies. The signaling responses were measured within a time range between immediately post-RE and >6 hours post-RE. Forty-four studies met the inclusion criteria, and all were classified as good-to-moderate methodological quality. Mitogen-activated protein kinase phosphorylation increased to different levels after RE, with the highest near the cessation of exercise. Although overall signaling was attenuated among trained individuals likely because of training adaptations, greater MAPK responses can be attributed to moderate loads of 65-85% 1RM regardless of the training experience. However, specific training-induced responses remain equivocal, and further investigations are required to determine the ideal training parameters to optimize anabolic intramuscular signaling, which may likely optimize resistance training adaptations.
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Affiliation(s)
- Christopher J Lee
- Department of Kinesiology, California State University, Northridge, Northridge, California
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5
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Battey E, Ross JA, Hoang A, Wilson DGS, Han Y, Levy Y, Pollock RD, Kalakoutis M, Pugh JN, Close GL, Ellison-Hughes GM, Lazarus NR, Iskratsch T, Harridge SDR, Ochala J, Stroud MJ. Myonuclear alterations associated with exercise are independent of age in humans. J Physiol 2023. [PMID: 36597809 DOI: 10.1113/jp284128] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2022] [Accepted: 12/19/2022] [Indexed: 01/05/2023] Open
Abstract
Age-related decline in skeletal muscle structure and function can be mitigated by regular exercise. However, the precise mechanisms that govern this are not fully understood. The nucleus plays an active role in translating forces into biochemical signals (mechanotransduction), with the nuclear lamina protein lamin A regulating nuclear shape, nuclear mechanics and ultimately gene expression. Defective lamin A expression causes muscle pathologies and premature ageing syndromes, but the roles of nuclear structure and function in physiological ageing and in exercise adaptations remain obscure. Here, we isolated single muscle fibres and carried out detailed morphological and functional analyses on myonuclei from young and older exercise-trained individuals. Strikingly, myonuclei from trained individuals were more spherical, less deformable, and contained a thicker nuclear lamina than those from untrained individuals. Complementary to this, exercise resulted in increased levels of lamin A and increased myonuclear stiffness in mice. We conclude that exercise is associated with myonuclear remodelling, independently of age, which may contribute to the preservative effects of exercise on muscle function throughout the lifespan. KEY POINTS: The nucleus plays an active role in translating forces into biochemical signals. Myonuclear aberrations in a group of muscular dystrophies called laminopathies suggest that the shape and mechanical properties of myonuclei are important for maintaining muscle function. Here, striking differences are presented in myonuclear shape and mechanics associated with exercise, in both young and old humans. Myonuclei from trained individuals were more spherical, less deformable and contained a thicker nuclear lamina than untrained individuals. It is concluded that exercise is associated with age-independent myonuclear remodelling, which may help to maintain muscle function throughout the lifespan.
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Affiliation(s)
- E Battey
- Centre for Human & Applied Physiological Sciences, Faculty of Life Sciences & Medicine, King's College London, London, UK
- British Heart Foundation Centre of Research Excellence, School of Cardiovascular Medicine and Sciences, King's College London, London, UK
- Novo Nordisk Foundation Center for Basic Metabolic Research, University of Copenhagen, Copenhagen, Denmark
| | - J A Ross
- British Heart Foundation Centre of Research Excellence, School of Cardiovascular Medicine and Sciences, King's College London, London, UK
| | - A Hoang
- British Heart Foundation Centre of Research Excellence, School of Cardiovascular Medicine and Sciences, King's College London, London, UK
| | - D G S Wilson
- School of Engineering and Materials Science, Queen Mary University of London, London, UK
| | - Y Han
- Centre for Human & Applied Physiological Sciences, Faculty of Life Sciences & Medicine, King's College London, London, UK
| | - Y Levy
- Centre for Human & Applied Physiological Sciences, Faculty of Life Sciences & Medicine, King's College London, London, UK
| | - R D Pollock
- Centre for Human & Applied Physiological Sciences, Faculty of Life Sciences & Medicine, King's College London, London, UK
| | - M Kalakoutis
- Centre for Human & Applied Physiological Sciences, Faculty of Life Sciences & Medicine, King's College London, London, UK
- Randall Centre for Cell and Molecular Biophysics, Faculty of Life Sciences & Medicine, King's College London, London, UK
| | - J N Pugh
- School of Sport and Exercise Sciences, Liverpool John Moores University, Liverpool, UK
| | - G L Close
- School of Sport and Exercise Sciences, Liverpool John Moores University, Liverpool, UK
| | - G M Ellison-Hughes
- Centre for Human & Applied Physiological Sciences, Faculty of Life Sciences & Medicine, King's College London, London, UK
| | - N R Lazarus
- Centre for Human & Applied Physiological Sciences, Faculty of Life Sciences & Medicine, King's College London, London, UK
| | - T Iskratsch
- School of Engineering and Materials Science, Queen Mary University of London, London, UK
- Randall Centre for Cell and Molecular Biophysics, Faculty of Life Sciences & Medicine, King's College London, London, UK
| | - S D R Harridge
- Centre for Human & Applied Physiological Sciences, Faculty of Life Sciences & Medicine, King's College London, London, UK
| | - J Ochala
- Centre for Human & Applied Physiological Sciences, Faculty of Life Sciences & Medicine, King's College London, London, UK
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - M J Stroud
- British Heart Foundation Centre of Research Excellence, School of Cardiovascular Medicine and Sciences, King's College London, London, UK
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6
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Muscle hypertrophy is correlated with load progression delta, climb volume, and total load volume in rodents undergoing different ladder-based resistance training protocols. Tissue Cell 2022; 75:101725. [DOI: 10.1016/j.tice.2021.101725] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2021] [Revised: 12/23/2021] [Accepted: 12/31/2021] [Indexed: 11/16/2022]
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7
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Chen MM, Zhao YP, Zhao Y, Deng SL, Yu K. Regulation of Myostatin on the Growth and Development of Skeletal Muscle. Front Cell Dev Biol 2022; 9:785712. [PMID: 35004684 PMCID: PMC8740192 DOI: 10.3389/fcell.2021.785712] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2021] [Accepted: 12/08/2021] [Indexed: 01/01/2023] Open
Abstract
Myostatin (MSTN), a member of the transforming growth factor-β superfamily, can negatively regulate the growth and development of skeletal muscle by autocrine or paracrine signaling. Mutation of the myostatin gene under artificial or natural conditions can lead to a significant increase in muscle quality and produce a double-muscle phenotype. Here, we review the similarities and differences between myostatin and other members of the transforming growth factor-β superfamily and the mechanisms of myostatin self-regulation. In addition, we focus extensively on the regulation of myostatin functions involved in myogenic differentiation, myofiber type conversion, and skeletal muscle protein synthesis and degradation. Also, we summarize the induction of reactive oxygen species generation and oxidative stress by myostatin in skeletal muscle. This review of recent insights into the function of myostatin will provide reference information for future studies of myostatin-regulated skeletal muscle formation and may have relevance to agricultural fields of study.
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Affiliation(s)
- Ming-Ming Chen
- College of Animal Science and Technology, China Agricultural University, Beijing, China
| | - Yi-Ping Zhao
- Tianjin Key Laboratory of Agricultural Animal Breeding and Healthy Husbandry, College of Animal Science and Veterinary Medicine, Tianjin Agricultural University, Tianjin, China
| | - Yue Zhao
- College of Animal Science and Technology, China Agricultural University, Beijing, China
| | - Shou-Long Deng
- NHC Key Laboratory of Human Disease Comparative Medicine, Institute of Laboratory Animal Sciences, Chinese Academy of Medical Sciences and Comparative Medicine Center, Peking Union Medical College, Beijing, China
| | - Kun Yu
- College of Animal Science and Technology, China Agricultural University, Beijing, China
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8
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Blonski S, Aureille J, Badawi S, Zaremba D, Pernet L, Grichine A, Fraboulet S, Korczyk PM, Recho P, Guilluy C, Dolega ME. Direction of epithelial folding defines impact of mechanical forces on epithelial state. Dev Cell 2021; 56:3222-3234.e6. [PMID: 34875225 DOI: 10.1016/j.devcel.2021.11.008] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2020] [Revised: 08/05/2021] [Accepted: 11/05/2021] [Indexed: 11/18/2022]
Abstract
Cell shape dynamics during development is tightly regulated and coordinated with cell fate determination. Triggered by an interplay between biochemical and mechanical signals, epithelia form complex tissues by undergoing coordinated cell shape changes, but how such spatiotemporal coordination is controlled remains an open question. To dissect biochemical signaling from purely mechanical cues, we developed a microfluidic system that experimentally triggers epithelial folding to recapitulate stereotypic deformations observed in vivo. Using this system, we observe that the apical or basal direction of folding results in strikingly different mechanical states at the fold boundary, where the balance between tissue tension and torque (arising from the imposed curvature) controls the spread of folding-induced calcium waves at a short timescale and induces spatial patterns of gene expression at longer timescales. Our work uncovers that folding-associated gradients of cell shape and their resulting mechanical stresses direct spatially distinct biochemical responses within the monolayer.
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Affiliation(s)
- Slawomir Blonski
- Institute of Fundamental Technological Research, IPPT, Polish Academy of Sciences, Department of Biosystems and Soft Matter, 02106 Warsaw, Poland
| | - Julien Aureille
- Institute for Advanced Biosciences, Department of Microenvironment, Cell Plasticity and Signaling, University Grenoble Alpes, Inserm U1209, CNRS UMR 5309, 38000 Grenoble, France
| | - Sara Badawi
- Institute for Advanced Biosciences, Department of Microenvironment, Cell Plasticity and Signaling, University Grenoble Alpes, Inserm U1209, CNRS UMR 5309, 38000 Grenoble, France
| | - Damian Zaremba
- Institute of Fundamental Technological Research, IPPT, Polish Academy of Sciences, Department of Biosystems and Soft Matter, 02106 Warsaw, Poland
| | - Lydia Pernet
- Institute for Advanced Biosciences, Department of Microenvironment, Cell Plasticity and Signaling, University Grenoble Alpes, Inserm U1209, CNRS UMR 5309, 38000 Grenoble, France
| | - Alexei Grichine
- Institute for Advanced Biosciences, Department of Microenvironment, Cell Plasticity and Signaling, University Grenoble Alpes, Inserm U1209, CNRS UMR 5309, 38000 Grenoble, France
| | - Sandrine Fraboulet
- Institute for Advanced Biosciences, Department of Microenvironment, Cell Plasticity and Signaling, University Grenoble Alpes, Inserm U1209, CNRS UMR 5309, 38000 Grenoble, France
| | - Piotr M Korczyk
- Institute of Fundamental Technological Research, IPPT, Polish Academy of Sciences, Department of Biosystems and Soft Matter, 02106 Warsaw, Poland
| | - Pierre Recho
- LIPhy, University Grenoble Alpes, CNRS UMR 5588, 38000 Grenoble, France
| | - Christophe Guilluy
- Institute for Advanced Biosciences, Department of Microenvironment, Cell Plasticity and Signaling, University Grenoble Alpes, Inserm U1209, CNRS UMR 5309, 38000 Grenoble, France.
| | - Monika E Dolega
- Institute for Advanced Biosciences, Department of Microenvironment, Cell Plasticity and Signaling, University Grenoble Alpes, Inserm U1209, CNRS UMR 5309, 38000 Grenoble, France.
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9
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Leser JM, Harriot A, Buck HV, Ward CW, Stains JP. Aging, Osteo-Sarcopenia, and Musculoskeletal Mechano-Transduction. FRONTIERS IN REHABILITATION SCIENCES 2021; 2:782848. [PMID: 36004321 PMCID: PMC9396756 DOI: 10.3389/fresc.2021.782848] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/24/2021] [Accepted: 11/10/2021] [Indexed: 11/13/2022]
Abstract
The decline in the mass and function of bone and muscle is an inevitable consequence of healthy aging with early onset and accelerated decline in those with chronic disease. Termed osteo-sarcopenia, this condition predisposes the decreased activity, falls, low-energy fractures, and increased risk of co-morbid disease that leads to musculoskeletal frailty. The biology of osteo-sarcopenia is most understood in the context of systemic neuro-endocrine and immune/inflammatory alterations that drive inflammation, oxidative stress, reduced autophagy, and cellular senescence in the bone and muscle. Here we integrate these concepts to our growing understanding of how bone and muscle senses, responds and adapts to mechanical load. We propose that age-related alterations in cytoskeletal mechanics alter load-sensing and mechano-transduction in bone osteocytes and muscle fibers which underscores osteo-sarcopenia. Lastly, we examine the evidence for exercise as an effective countermeasure to osteo-sarcopenia.
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Affiliation(s)
| | | | | | | | - Joseph P. Stains
- Department of Orthopaedics, University of Maryland School of Medicine, Baltimore, MD, United States
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10
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Wette SG, Lamb GD, Murphy RM. Nuclei isolation methods fail to accurately assess the subcellular localization and behaviour of proteins in skeletal muscle. Acta Physiol (Oxf) 2021; 233:e13730. [PMID: 34492163 DOI: 10.1111/apha.13730] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2021] [Revised: 09/04/2021] [Accepted: 09/05/2021] [Indexed: 12/17/2022]
Abstract
AIM Subcellular fractionation is often used to determine the subcellular localization of proteins, including whether a protein translocates to the nucleus in response to a given stimulus. Examining nuclear proteins in skeletal muscle is difficult because myonuclear proteins are challenging to isolate unless harsh treatments are used. This study aimed to determine the most effective method for isolating and preserving proteins in their native state in skeletal muscle. METHODS We compared the ability of detergents, commercially available kit-based and K+ -based physiological methodologies for isolating myonuclear proteins from resting samples of human muscle by determining the presence of marker proteins for each fraction by western blot analyses. RESULTS We found that following the initial pelleting of nuclei, treatment with 1% Triton-X 100, 1% CHAPS or 0.5% Na-deoxycholate under various ionic conditions resulted in the nuclear proteins being either resistant to isolation or the proteins present behaving aberrantly. The nuclear proteins in brain tissue were also resistant to 1% Triton-X 100 isolation. Here, we demonstrate aberrant behaviour and erroneous localization of proteins using the kit-based method. The aberrant behaviour was the activation of Ca2+ -dependent protease calpain-3, and the erroneous localization was the presence of calpain-3 and troponin I in the nuclear fraction. CONCLUSION Our findings indicate that it may not be possible to reliably determine the translocation of proteins between subcellular locations and the nucleus using subcellular fractionation techniques. This study highlights the importance of validating subcellular fractionation methodologies using several subcellular-specific markers and solutions that are physiologically relevant to the intracellular milieu.
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Affiliation(s)
- Stefan G. Wette
- Department of Biochemistry and Genetics La Trobe Institute for Molecular ScienceLa Trobe University Melbourne Victoria Australia
| | - Graham D. Lamb
- Department of Physiology, Anatomy and Microbiology School of Life Sciences La Trobe University Melbourne Victoria Australia
| | - Robyn M. Murphy
- Department of Biochemistry and Genetics La Trobe Institute for Molecular ScienceLa Trobe University Melbourne Victoria Australia
- Department of Physiology, Anatomy and Microbiology School of Life Sciences La Trobe University Melbourne Victoria Australia
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11
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Eftestøl E, Franchi MV, Kasper S, Flück M. JNK activation in TA and EDL muscle is load-dependent in rats receiving identical excitation patterns. Sci Rep 2021; 11:16405. [PMID: 34385505 PMCID: PMC8361015 DOI: 10.1038/s41598-021-94930-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2021] [Accepted: 07/12/2021] [Indexed: 11/09/2022] Open
Abstract
As the excitation-contraction coupling is inseparable during voluntary exercise, the relative contribution of the mechanical and neural input on hypertrophy-related molecular signalling is still poorly understood. Herein, we use a rat in-vivo strength exercise model with an electrically-induced standardized excitation pattern, previously shown to induce a load-dependent increase in myonuclear number and hypertrophy, to study acute effects of load on molecular signalling. We assessed protein abundance and specific phosphorylation of the four protein kinases FAK, mTOR, p70S6K and JNK after 2, 10 and 28 min of a low- or high-load contraction, in order to assess the effects of load, exercise duration and muscle-type on their response to exercise. Specific phosphorylation of mTOR, p70S6K and JNK was increased after 28 min of exercise under the low- and high-load protocol. Elevated phosphorylation of mTOR and JNK was detectable already after 2 and 10 min of exercise, respectively, but greatest after 28 min of exercise, and JNK phosphorylation was highly load-dependent. The abundance of all four kinases was higher in TA compared to EDL muscle, p70S6K abundance was increased after exercise in a load-independent manner, and FAK and JNK abundance was reduced after 28 min of exercise in both the exercised and control muscles. In conclusion, the current study shows that JNK activation after a single resistance exercise is load-specific, resembling the previously reported degree of myonuclear accrual and muscle hypertrophy with repetition of the exercise stimulus.
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Affiliation(s)
- Einar Eftestøl
- Department of Biosciences, University of Oslo, Kristine Bonnevies hus, Blindernveien 31, 0371, Oslo, Norway.
| | - Martino V Franchi
- Laboratory for Muscle Plasticity, Department of Orthopaedics, University of Zürich, Zurich, Switzerland.,Department of Biomedical Sciences, University of Padova, Padua, Italy
| | - Stephanie Kasper
- Laboratory for Muscle Plasticity, Department of Orthopaedics, University of Zürich, Zurich, Switzerland
| | - Martin Flück
- Laboratory for Muscle Plasticity, Department of Orthopaedics, University of Zürich, Zurich, Switzerland
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12
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van Ingen MJA, Kirby TJ. LINCing Nuclear Mechanobiology With Skeletal Muscle Mass and Function. Front Cell Dev Biol 2021; 9:690577. [PMID: 34368139 PMCID: PMC8335485 DOI: 10.3389/fcell.2021.690577] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2021] [Accepted: 06/25/2021] [Indexed: 11/13/2022] Open
Abstract
Skeletal muscle demonstrates a high degree of adaptability in response to changes in mechanical input. The phenotypic transformation in response to mechanical cues includes changes in muscle mass and force generating capabilities, yet the molecular pathways that govern skeletal muscle adaptation are still incompletely understood. While there is strong evidence that mechanotransduction pathways that stimulate protein synthesis play a key role in regulation of muscle mass, there are likely additional mechano-sensitive mechanisms important for controlling functional muscle adaptation. There is emerging evidence that the cell nucleus can directly respond to mechanical signals (i.e., nuclear mechanotransduction), providing a potential additional level of cellular regulation for controlling skeletal muscle mass. The importance of nuclear mechanotransduction in cellular function is evident by the various genetic diseases that arise from mutations in proteins crucial to the transmission of force between the cytoskeleton and the nucleus. Intriguingly, these diseases preferentially affect cardiac and skeletal muscle, suggesting that nuclear mechanotransduction is critically important for striated muscle homeostasis. Here we discuss our current understanding for how the nucleus acts as a mechanosensor, describe the main cytoskeletal and nuclear proteins involved in the process, and propose how similar mechanoresponsive mechanisms could occur in the unique cellular environment of a myofiber. In addition, we examine how nuclear mechanotransduction fits into our current framework for how mechanical stimuli regulates skeletal muscle mass.
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Affiliation(s)
- Maria J A van Ingen
- Biomolecular Sciences, Faculty of Science, Vrije Universiteit Amsterdam, Amsterdam, Netherlands
| | - Tyler J Kirby
- Department of Physiology, Amsterdam Cardiovascular Sciences, Amsterdam Movement Sciences, Amsterdam UMC, Amsterdam, Netherlands
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13
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Kotani T, Takegaki J, Tamura Y, Kouzaki K, Nakazato K, Ishii N. Repeated bouts of resistance exercise in rats alter mechanistic target of rapamycin complex 1 activity and ribosomal capacity but not muscle protein synthesis. Exp Physiol 2021; 106:1950-1960. [PMID: 34197668 DOI: 10.1113/ep089699] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2021] [Accepted: 06/30/2021] [Indexed: 01/03/2023]
Abstract
NEW FINDINGS What is the central question of this study? Is muscle protein synthesis (MPS) additionally activated following exercise when ribosomal capacity is increased after repeated bouts of resistance exercise (RE)? What is the main finding and its importance? Skeletal muscles with increased ribosome content through repeated RE bouts showed sufficient activation of MPS with lower mechanistic target of rapamycin complex 1 signalling. Thus, repeated bouts of RE possibly change the translational capacity and efficiency to optimize translation activation following RE. ABSTRACT Resistance exercise (RE) activates ribosome biogenesis and increases ribosome content in skeletal muscles. However, it is unclear whether the increase in ribosome content subsequently causes an increase in RE-induced activation of muscle protein synthesis (MPS). Thus, this study aimed to investigate the relationship between ribosome content and MPS after exercise using a rat RE model. Male Sprague-Dawley rats were categorized into three groups (n = 6 for each group): sedentary (SED) and RE trained with one bout (1B) or three bouts (3B). The RE stimulus was applied to the right gastrocnemius muscle by transcutaneous electrical stimulation under isoflurane anaesthesia. The 3B group underwent stimulation every other day. Our results revealed that 6 h after the last bout of RE, muscles in the 3B group showed an increase in total RNA and 18S+28S rRNA content per muscle weight compared with the SED and 1B groups. In both the 1B and 3B groups, MPS, estimated by puromycin incorporation in proteins, was higher than that in the SED group 6 h after exercise; however, no significant difference was observed between the 1B and 3B groups. In the 1B and 3B groups, phosphorylated p70S6K at Thr-389 increased, indicating mechanistic target of rapamycin complex 1 (mTORC1) activity. p70S6K phosphorylation level was lower in the 3B group than in the 1B group. Finally, protein synthesis per ribosome (indicator of translation efficiency) was lower in the 3B group than in the 1B group. Thus, three bouts of RE changed the ribosome content and mTORC1 activation, but not the degree of RE-induced global MPS activation.
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Affiliation(s)
- Takaya Kotani
- Research Institute for Sport Science, Nippon Sport Science University, Tokyo, Japan
| | - Junya Takegaki
- Ritsumeikan Global Innovation Research Organization, Ritsumeikan University, Shiga, Japan
| | - Yuki Tamura
- Research Institute for Sport Science, Nippon Sport Science University, Tokyo, Japan.,Graduate School of Health and Sport Science, Nippon Sport Science University, Tokyo, Japan.,Faculty of Sport Science, Nippon Sport Science University, Tokyo, Japan
| | - Karina Kouzaki
- Research Institute for Sport Science, Nippon Sport Science University, Tokyo, Japan.,Graduate School of Medical and Health Science, Nippon Sport Science University, Tokyo, Japan.,Faculty of Medical Science, Nippon Sport Science University, Tokyo, Japan
| | - Koichi Nakazato
- Research Institute for Sport Science, Nippon Sport Science University, Tokyo, Japan.,Graduate School of Health and Sport Science, Nippon Sport Science University, Tokyo, Japan.,Graduate School of Medical and Health Science, Nippon Sport Science University, Tokyo, Japan.,Faculty of Medical Science, Nippon Sport Science University, Tokyo, Japan
| | - Naokata Ishii
- Graduate School or Arts and Sciences, The University of Tokyo, Tokyo, Japan
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14
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Aureille J, Pezet M, Pernet L, Mazzega J, Grichine A, Guilluy C, Dolega ME. Cell fluorescence photoactivation as a method to select and study cellular subpopulations grown in mechanically heterogeneous environments. Mol Biol Cell 2021; 32:1409-1416. [PMID: 34133212 PMCID: PMC8351743 DOI: 10.1091/mbc.e20-10-0676] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
A central challenge to the biology of development and disease is deciphering how individual cells process and respond to numerous biochemical and mechanical signals originating from the environment. Recent advances in genomic studies enabled the acquisition of information about population heterogeneity; however, these so far are poorly linked with the spatial heterogeneity of biochemical and mechanical cues. Whereas in vitro models offer superior control over spatiotemporal distribution of numerous mechanical parameters, researchers are limited by the lack of methods to select subpopulations of cells in order to understand how environmental heterogeneity directs the functional collective response. To circumvent these limitations, we present a method based on the use of photo convertible proteins, which when expressed within cells and activated with light, gives a stable fluorescence fingerprint enabling subsequent sorting and lysis for genomics analysis. Using this technique, we study the spatial distribution of genetic alterations on well-characterized local mechanical stimulation within the epithelial monolayer. Our method is an in vitro alternative to laser microdissection, which so far has found a broad application in ex vivo studies.
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Affiliation(s)
- Julien Aureille
- Institute for Advanced Biosciences, University Grenoble Alpes, Inserm U1209, CNRS UMR 5309 Grenoble, France
| | - Mylène Pezet
- Institute for Advanced Biosciences, University Grenoble Alpes, Inserm U1209, CNRS UMR 5309 Grenoble, France
| | - Lydia Pernet
- Institute for Advanced Biosciences, University Grenoble Alpes, Inserm U1209, CNRS UMR 5309 Grenoble, France
| | - Jacques Mazzega
- Institute for Advanced Biosciences, University Grenoble Alpes, Inserm U1209, CNRS UMR 5309 Grenoble, France
| | - Alexei Grichine
- Institute for Advanced Biosciences, University Grenoble Alpes, Inserm U1209, CNRS UMR 5309 Grenoble, France
| | - Christophe Guilluy
- Institute for Advanced Biosciences, University Grenoble Alpes, Inserm U1209, CNRS UMR 5309 Grenoble, France
| | - Monika Elzbieta Dolega
- Institute for Advanced Biosciences, University Grenoble Alpes, Inserm U1209, CNRS UMR 5309 Grenoble, France
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15
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Van Pelt DW, Lawrence MM, Miller BF, Butterfield TA, Dupont-Versteegden EE. Massage as a Mechanotherapy for Skeletal Muscle. Exerc Sport Sci Rev 2021; 49:107-114. [PMID: 33720912 PMCID: PMC8320327 DOI: 10.1249/jes.0000000000000244] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Massage is anecdotally associated with many health benefits, but physiological and clinically relevant mechanisms recently have begun to be investigated in a controlled manner. Herein, we describe research supporting our hypothesis that massage can be used as a mechanotherapy imparting biologically relevant adaptations in skeletal muscle and improving muscle properties.
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Affiliation(s)
- Douglas W Van Pelt
- Department of Physical Therapy and Center for Muscle Biology, University of Kentucky, Lexington, KY
| | - Marcus M Lawrence
- Aging and Metabolism Research Program, Oklahoma Medical Research Foundation, Oklahoma City, OK
| | - Benjamin F Miller
- Aging and Metabolism Research Program, Oklahoma Medical Research Foundation, Oklahoma City, OK
| | - Timothy A Butterfield
- Department of Athletic Training and Clinical Nutrition and Center for Muscle Biology, University of Kentucky, Lexington, KY
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16
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Peris-Moreno D, Cussonneau L, Combaret L, Polge C, Taillandier D. Ubiquitin Ligases at the Heart of Skeletal Muscle Atrophy Control. Molecules 2021; 26:molecules26020407. [PMID: 33466753 PMCID: PMC7829870 DOI: 10.3390/molecules26020407] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2020] [Revised: 01/08/2021] [Accepted: 01/10/2021] [Indexed: 02/07/2023] Open
Abstract
Skeletal muscle loss is a detrimental side-effect of numerous chronic diseases that dramatically increases mortality and morbidity. The alteration of protein homeostasis is generally due to increased protein breakdown while, protein synthesis may also be down-regulated. The ubiquitin proteasome system (UPS) is a master regulator of skeletal muscle that impacts muscle contractile properties and metabolism through multiple levers like signaling pathways, contractile apparatus degradation, etc. Among the different actors of the UPS, the E3 ubiquitin ligases specifically target key proteins for either degradation or activity modulation, thus controlling both pro-anabolic or pro-catabolic factors. The atrogenes MuRF1/TRIM63 and MAFbx/Atrogin-1 encode for key E3 ligases that target contractile proteins and key actors of protein synthesis respectively. However, several other E3 ligases are involved upstream in the atrophy program, from signal transduction control to modulation of energy balance. Controlling E3 ligases activity is thus a tempting approach for preserving muscle mass. While indirect modulation of E3 ligases may prove beneficial in some situations of muscle atrophy, some drugs directly inhibiting their activity have started to appear. This review summarizes the main signaling pathways involved in muscle atrophy and the E3 ligases implicated, but also the molecules potentially usable for future therapies.
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17
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Romani P, Valcarcel-Jimenez L, Frezza C, Dupont S. Crosstalk between mechanotransduction and metabolism. Nat Rev Mol Cell Biol 2021; 22:22-38. [PMID: 33188273 DOI: 10.1038/s41580-020-00306-w] [Citation(s) in RCA: 167] [Impact Index Per Article: 55.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/07/2020] [Indexed: 12/22/2022]
Abstract
Mechanical forces shape cells and tissues during development and adult homeostasis. In addition, they also signal to cells via mechanotransduction pathways to control cell proliferation, differentiation and death. These processes require metabolism of nutrients for both energy generation and biosynthesis of macromolecules. However, how cellular mechanics and metabolism are connected is still poorly understood. Here, we discuss recent evidence indicating how the mechanical cues exerted by the extracellular matrix (ECM), cell-ECM and cell-cell adhesion complexes influence metabolic pathways. Moreover, we explore the energy and metabolic requirements associated with cell mechanics and ECM remodelling, implicating a reciprocal crosstalk between cell mechanics and metabolism.
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Affiliation(s)
- Patrizia Romani
- Department of Molecular Medicine, University of Padua Medical School, Padua, Italy
| | | | - Christian Frezza
- MRC Cancer Unit, University of Cambridge, Hutchison/MRC Research Centre, Cambridge, UK.
| | - Sirio Dupont
- Department of Molecular Medicine, University of Padua Medical School, Padua, Italy.
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18
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The Paradoxical Effect of PARP Inhibitor BGP-15 on Irinotecan-Induced Cachexia and Skeletal Muscle Dysfunction. Cancers (Basel) 2020; 12:cancers12123810. [PMID: 33348673 PMCID: PMC7766767 DOI: 10.3390/cancers12123810] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2020] [Accepted: 12/14/2020] [Indexed: 12/24/2022] Open
Abstract
Simple Summary Both cancer and the chemotherapy used to treat it are drivers of cachexia, a life-threatening body-wasting condition which complicates cancer treatment. Poly-(ADP-ribose) polymerase (PARP) inhibitors are currently being investigated as a treatment against cancer. Here, we present paradoxical evidence that they might also be useful for mitigating the skeletal muscle specific side-effects of anti-cancer chemotherapy or exacerbate them. BGP-15 is a small molecule PARP inhibitor which protected against irinotecan (IRI)-induced cachexia and loss of skeletal muscle mass and dysfunction in our study. However, peculiarly, BGP-15 adjuvant therapy reduced protein synthesis rates and the expression of key cytoskeletal proteins associated with the dystrophin-associated protein complex and increased matrix metalloproteinase activity, while it increased the propensity for fast-twitch muscles to tear during fatiguing contraction. Our data suggest that both IRI and BGP-15 cause structural remodeling involving proteins associated with the contractile apparatus, cytoskeleton and/or the extracellular matrix which may be only transient and ultimately beneficial or may paradoxically onset a muscular dystrophy phenotype and be detrimental if more permanent. Abstract Chemotherapy-induced muscle wasting and dysfunction is a contributing factor to cachexia alongside cancer and increases the risk of morbidity and mortality. Here, we investigate the effects of the chemotherapeutic agent irinotecan (IRI) on skeletal muscle mass and function and whether BGP-15 (a poly-(ADP-ribose) polymerase-1 (PARP-1) inhibitor and heat shock protein co-inducer) adjuvant therapy could protect against IRI-induced skeletal myopathy. Healthy 6-week-old male Balb/C mice (n = 24; 8/group) were treated with six intraperitoneal injections of either vehicle, IRI (30 mg/kg) or BGP-15 adjuvant therapy (IRI+BGP; 15 mg/kg) over two weeks. IRI reduced lean and tibialis anterior mass, which were attenuated by IRI+BGP treatment. Remarkably, IRI reduced muscle protein synthesis, while IRI+BGP reduced protein synthesis further. These changes occurred in the absence of a change in crude markers of mammalian/mechanistic target of rapamycin (mTOR) Complex 1 (mTORC1) signaling and protein degradation. Interestingly, the cytoskeletal protein dystrophin was reduced in both IRI- and IRI+BGP-treated mice, while IRI+BGP treatment also decreased β-dystroglycan, suggesting significant remodeling of the cytoskeleton. IRI reduced absolute force production of the soleus and extensor digitorum longus (EDL) muscles, while IRI+BGP rescued absolute force production of the soleus and strongly trended to rescue force output of the EDL (p = 0.06), which was associated with improvements in mass. During the fatiguing stimulation, IRI+BGP-treated EDL muscles were somewhat susceptible to rupture at the musculotendinous junction, likely due to BGP-15’s capacity to maintain the rate of force development within a weakened environment characterized by significant structural remodeling. Our paradoxical data highlight that BGP-15 has some therapeutic advantage by attenuating IRI-induced skeletal myopathy; however, its effects on the remodeling of the cytoskeleton and extracellular matrix, which appear to make fast-twitch muscles more prone to tearing during contraction, could suggest the induction of muscular dystrophy and, thus, require further characterization.
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19
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Machek SB, Cardaci TD, Wilburn DT, Willoughby DS. Considerations, possible contraindications, and potential mechanisms for deleterious effect in recreational and athletic use of selective androgen receptor modulators (SARMs) in lieu of anabolic androgenic steroids: A narrative review. Steroids 2020; 164:108753. [PMID: 33148520 DOI: 10.1016/j.steroids.2020.108753] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/17/2020] [Revised: 10/07/2020] [Accepted: 10/17/2020] [Indexed: 12/12/2022]
Abstract
Anabolic androgenic steroids (AAS) are testosterone and testosterone-derivative compounds sporadically employed by athletes and increasingly used recreationally to acquire a competitive edge or improve body composition. Nevertheless, users are subject to undesired side effects majorly associated with tissue-specific androgen receptor (AR) binding-mediated actions. More recently, selective AR modulators (SARMs) have gained popularity towards delivering androgen-associated anabolic actions with hopes of minimal androgenic effects. While several SARMs are in preclinical and clinical phases intended for demographics subject to hypogonadism, muscle wasting, and osteoporosis, several athletic organizations and drug testing affiliates have realized the increasingly widespread use of SARMs amongst competitors and have subsequently banned their use. Furthermore, recreational users are haphazardly acquiring these compounds from the internet and consuming doses several times greater than empirically reported. Unfortunately, online sources are rife with potential contamination, despite a prevailing public opinion suggesting SARMs are innocuous AAS alternatives. Considering each agent has a broad range of supporting evidence in both human and non-human models, it is important to comprehensively evaluate the current literature on commercially available SARMs to gain better understanding of their efficacy and if they can truly be considered a safer AAS alternative. Therefore, the purpose of this review is to discuss the current evidence regarding AAS and SARM mechanisms of action, demonstrate the efficacy of several prominent SARMs in a variety of scientific trials, and theorize on the wide-ranging contraindications and potential deleterious effects, as well as potential future directions regarding acute and chronic SARM use across a broad range of demographics.
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Affiliation(s)
- Steven B Machek
- Exercise & Biochemical Nutrition Laboratory, Department of Health, Human Performance, and Recreation. Robbins College of Health and Human Sciences, Baylor University, Waco, TX, USA
| | - Thomas D Cardaci
- Exercise & Biochemical Nutrition Laboratory, Department of Health, Human Performance, and Recreation. Robbins College of Health and Human Sciences, Baylor University, Waco, TX, USA; Department of Exercise Science, Arnold School of Public Health, University of South Carolina, Columbia, SC, USA
| | - Dylan T Wilburn
- Exercise & Biochemical Nutrition Laboratory, Department of Health, Human Performance, and Recreation. Robbins College of Health and Human Sciences, Baylor University, Waco, TX, USA
| | - Darryn S Willoughby
- Mayborn College of Health Sciences, School of Exercise and Sport Science, University of Mary Hardin-Baylor, Belton, TX, USA.
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20
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Mirzoev TM. Skeletal Muscle Recovery from Disuse Atrophy: Protein Turnover Signaling and Strategies for Accelerating Muscle Regrowth. Int J Mol Sci 2020; 21:ijms21217940. [PMID: 33114683 PMCID: PMC7663166 DOI: 10.3390/ijms21217940] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2020] [Revised: 10/08/2020] [Accepted: 10/23/2020] [Indexed: 12/15/2022] Open
Abstract
Skeletal muscle fibers have a unique capacity to adjust their metabolism and phenotype in response to alternations in mechanical loading. Indeed, chronic mechanical loading leads to an increase in skeletal muscle mass, while prolonged mechanical unloading results in a significant decrease in muscle mass (muscle atrophy). The maintenance of skeletal muscle mass is dependent on the balance between rates of muscle protein synthesis and breakdown. While molecular mechanisms regulating protein synthesis during mechanical unloading have been relatively well studied, signaling events implicated in protein turnover during skeletal muscle recovery from unloading are poorly defined. A better understanding of the molecular events that underpin muscle mass recovery following disuse-induced atrophy is of significant importance for both clinical and space medicine. This review focuses on the molecular mechanisms that may be involved in the activation of protein synthesis and subsequent restoration of muscle mass after a period of mechanical unloading. In addition, the efficiency of strategies proposed to improve muscle protein gain during recovery is also discussed.
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Affiliation(s)
- Timur M Mirzoev
- Myology Laboratory, Institute of Biomedical Problems RAS, Moscow 123007, Russia
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21
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Dupont-Versteegden EE, McCarthy JJ. Translational control of muscle mass. J Appl Physiol (1985) 2020; 127:579-580. [PMID: 31446832 DOI: 10.1152/japplphysiol.00497.2019] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Affiliation(s)
| | - John J McCarthy
- Department of Physiology, College of Medicine, University of Kentucky, Lexington, Kentucky
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22
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Dissecting the Effect of a 3D Microscaffold on the Transcriptome of Neural Stem Cells with Computational Approaches: A Focus on Mechanotransduction. Int J Mol Sci 2020; 21:ijms21186775. [PMID: 32942778 PMCID: PMC7555048 DOI: 10.3390/ijms21186775] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2020] [Revised: 09/05/2020] [Accepted: 09/14/2020] [Indexed: 12/16/2022] Open
Abstract
3D cell cultures are becoming more and more important in the field of regenerative medicine due to their ability to mimic the cellular physiological microenvironment. Among the different types of 3D scaffolds, we focus on the Nichoid, a miniaturized scaffold with a structure inspired by the natural staminal niche. The Nichoid can activate cellular responses simply by subjecting the cells to mechanical stimuli. This kind of influence results in different cellular morphology and organization, but the molecular bases of these changes remain largely unknown. Through RNA-Seq approach on murine neural precursors stem cells expanded inside the Nichoid, we investigated the deregulated genes and pathways showing that the Nichoid causes alteration in genes strongly connected to mechanobiological functions. Moreover, we fully dissected this mechanism highlighting how the changes start at a membrane level, with subsequent alterations in the cytoskeleton, signaling pathways, and metabolism, all leading to a final alteration in gene expression. The results shown here demonstrate that the Nichoid influences the biological and genetic response of stem cells thorough specific alterations of cellular signaling. The characterization of these pathways elucidates the role of mechanical manipulation on stem cells, with possible implications in regenerative medicine applications.
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23
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Hardee JP, Fix DK, Koh HJ, Wang X, Goldsmith EC, Carson JA. Repeated eccentric contractions positively regulate muscle oxidative metabolism and protein synthesis during cancer cachexia in mice. J Appl Physiol (1985) 2020; 128:1666-1676. [PMID: 32407241 DOI: 10.1152/japplphysiol.00908.2019] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Cancer-induced wasting is accompanied by disruptions to muscle oxidative metabolism and protein turnover that have been associated with systemic inflammation, whereas exercise and stimulated muscle contractions can positively regulate muscle protein synthesis and mitochondrial homeostasis. In preclinical cancer cachexia models, a single bout of eccentric contractions (ECCs) can induce protein synthesis and repeated ECC bouts prevent myofiber atrophy. The cellular mechanisms providing this protection from atrophy have not been resolved. Therefore, the purpose of this study was to determine whether repeated stimulated ECC bouts affect basal muscle oxidative metabolism and protein synthesis during cancer cachexia, and if these changes were associated with plasma IL-6 levels. Male ApcMin/+ (MIN; n = 10) mice initiating cachexia and healthy C57BL/6 (B6; n = 11) control mice performed repeated ECC bouts over 2 wk. MIN mice exhibited body weight loss and elevated plasma IL-6 before and during repeated ECC bouts. Control MIN muscle demonstrated disrupted signaling related to inflammation, oxidative capacity, and protein synthesis regulation, which were all improved by repeated ECC bouts. With cachexia, plasma IL-6 levels were negatively correlated with myofiber cross-sectional area, oxidative capacity, and protein synthesis. Interestingly, ECC improvements in these outcomes were positively correlated with plasma IL-6 levels in MIN mice. There was also a positive relationship between muscle oxidative capacity and protein synthesis after repeated ECC bouts in MIN mice. Collectively, repeated ECC bouts altered the cachectic muscle phenotype independent of systemic wasting, and there was a strong association between muscle oxidative capacity and protein synthesis in this adaptive response.NEW & NOTEWORTHY Cancer-induced muscle wasting is accompanied by disruptions to muscle oxidative metabolism and protein turnover regulation, whereas exercise is a potent stimulator of muscle protein synthesis and mitochondrial homeostasis. In a preclinical model of cancer cachexia, we report that cachectic muscle retains anabolic and metabolic plasticity to repeated eccentric contraction bouts despite an overall systemic wasting environment. The attenuation of muscle atrophy is linked to improved oxidative capacity and protein synthesis during cancer cachexia progression.
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Affiliation(s)
- Justin P Hardee
- Department of Exercise Science, University of South Carolina, Columbia, South Carolina
| | - Dennis K Fix
- Department of Exercise Science, University of South Carolina, Columbia, South Carolina
| | - Ho-Jin Koh
- Department of Exercise Science, University of South Carolina, Columbia, South Carolina
| | - Xuewen Wang
- Department of Exercise Science, University of South Carolina, Columbia, South Carolina
| | - Edie C Goldsmith
- Department of Cell Biology and Anatomy, University of South Carolina School of Medicine, Columbia, South Carolina
| | - James A Carson
- Center for Muscle Metabolism and Neuropathology, Division of Rehabilitation Sciences, College of Health Professions, University of Tennessee Health Science Center, Memphis, Tennessee
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