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Dugdale HF, Levy Y, Jungbluth H, Oldfors A, Ochala J. Aberrant myonuclear domains and impaired myofiber contractility despite marked hypertrophy in MYMK-related, Carey-Fineman-Ziter Syndrome. Acta Neuropathol Commun 2024; 12:80. [PMID: 38790073 PMCID: PMC11127446 DOI: 10.1186/s40478-024-01783-2] [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: 02/09/2024] [Accepted: 04/10/2024] [Indexed: 05/26/2024] Open
Abstract
Carey Fineman Ziter Syndrome (CFZS) is a rare autosomal recessive disease caused by mutations in the MYMK locus which encodes the protein, myomaker. Myomaker is essential for fusion and concurrent myonuclei donation of muscle progenitors during growth and development. Strikingly, in humans, MYMK mutations appear to prompt myofiber hypertrophy but paradoxically, induce generalised muscle weakness. As the underlying cellular mechanisms remain unexplored, the present study aimed to gain insights by combining myofiber deep-phenotyping and proteomic profiling. Hence, we isolated individual muscle fibers from CFZS patients and performed mechanical, 3D morphological and proteomic analyses. Myofibers from CFZS patients were ~ 4x larger than controls and possessed ~ 2x more myonuclei than those from healthy subjects, leading to disproportionally larger myonuclear domain volumes. These greater myonuclear domain sizes were accompanied by smaller intrinsic cellular force generating-capacities in myofibers from CFZS patients than in control muscle cells. Our complementary proteomic analyses indicated remodelling in 233 proteins particularly those associated with cellular respiration. Overall, our findings suggest that myomaker is somewhat functional in CFZS patients, but the associated nuclear accretion may ultimately lead to non-functional hypertrophy and altered energy-related mechanisms in CFZS patients. All of these are likely contributors of the muscle weakness experienced by CFZS patients.
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Affiliation(s)
- Hannah F Dugdale
- School of Sport, Exercise and Health Sciences, Loughborough University, Loughborough, UK
- Centre for Human and Applied Physiological Sciences, School of Basic and Medical Biosciences, Faculty of Life Sciences and Medicine, King's College London, London, UK
| | - Yotam Levy
- Centre for Human and Applied Physiological Sciences, School of Basic and Medical Biosciences, Faculty of Life Sciences and Medicine, King's College London, London, UK
| | - Heinz Jungbluth
- Randall Centre for Cell and Molecular Biophysics, Muscle Signalling Section, Faculty of Life Sciences and Medicine (FoLSM), King's College London, London, UK
- Department of Paediatric Neurology, Neuromuscular Service, Evelina Children's Hospital, Guy's and St Thomas' Hospital NHS Foundation Trust, London, UK
| | - Anders Oldfors
- Department of Laboratory Medicine, University of Gothenburg, Gothenburg, Sweden
| | - Julien Ochala
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.
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2
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Meinhold M, Verbrugge S, Shi A, Schönfelder M, Becker L, Jaspers RT, Zammit PS, Wackerhage H. Yap/Taz activity is associated with increased expression of phosphoglycerate dehydrogenase that supports myoblast proliferation. Cell Tissue Res 2024; 395:271-283. [PMID: 38183459 PMCID: PMC10904560 DOI: 10.1007/s00441-023-03851-w] [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: 05/17/2023] [Accepted: 11/24/2023] [Indexed: 01/08/2024]
Abstract
In skeletal muscle, the Hippo effector Yap promotes satellite cell, myoblast, and rhabdomyoblast proliferation but prevents myogenic differentiation into multinucleated muscle fibres. We previously noted that Yap drives expression of the first enzyme of the serine biosynthesis pathway, phosphoglycerate dehydrogenase (Phgdh). Here, we examined the regulation and function of Phgdh in satellite cells and myoblasts and found that Phgdh protein increased during satellite cell activation. Analysis of published data reveal that Phgdh mRNA in mouse tibialis anterior muscle was highly expressed at day 3 of regeneration after cardiotoxin injection, when markers of proliferation are also robustly expressed and in the first week of synergist-ablated muscle. Finally, siRNA-mediated knockdown of PHGDH significantly reduced myoblast numbers and the proliferation rate. Collectively, our data suggest that Phgdh is a proliferation-enhancing metabolic enzyme that is induced when quiescent satellite cells become activated.
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Affiliation(s)
- Marius Meinhold
- School of Medicine and Health, Technical University of Munich, Connollystrasse 32, 80809, Munich, Germany.
| | - Sander Verbrugge
- School of Medicine and Health, Technical University of Munich, Connollystrasse 32, 80809, Munich, Germany
| | - Andi Shi
- Laboratory for Myology, Department of Human Movement Sciences, Faculty of Behavioural and Movement Sciences, Amsterdam Movement Sciences, Vrije Universiteit Amsterdam, De Boelelaan 1108, 1081 HZ, Amsterdam, The Netherlands
- Department of Prosthodontics, Guangdong Engineering Research Center of Oral Restoration and Reconstruction, Guangzhou Key Laboratory of Basic and Applied Research of Oral Regenerative Medicine, Affiliated Stomatology Hospital of Guangzhou Medical University, Guangzhou, China
| | - Martin Schönfelder
- School of Medicine and Health, Technical University of Munich, Connollystrasse 32, 80809, Munich, Germany
| | - Lore Becker
- Institute of Experimental Genetics, Helmholtz Zentrum München, German Research Center for Environmental Health, German Mouse Clinic, Ingolstädter Landstrasse 1, 85764, Neuherberg, Germany
| | - Richard T Jaspers
- Laboratory for Myology, Department of Human Movement Sciences, Faculty of Behavioural and Movement Sciences, Amsterdam Movement Sciences, Vrije Universiteit Amsterdam, De Boelelaan 1108, 1081 HZ, Amsterdam, The Netherlands
- Department of Prosthodontics, Guangdong Engineering Research Center of Oral Restoration and Reconstruction, Guangzhou Key Laboratory of Basic and Applied Research of Oral Regenerative Medicine, Affiliated Stomatology Hospital of Guangzhou Medical University, Guangzhou, China
| | - Peter S Zammit
- Randall Centre for Cell and Molecular Biophysics, King's College London, New Hunt's House, Guy's Campus, London, SE1 1UL, UK
| | - Henning Wackerhage
- School of Medicine and Health, Technical University of Munich, Connollystrasse 32, 80809, Munich, Germany
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3
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Stadhouders LEM, Smith JAB, Gabriel BM, Verbrugge SAJ, Hammersen TD, Kolijn D, Vogel ISP, Mohamed AD, de Wit GMJ, Offringa C, Hoogaars WMH, Gehlert S, Wackerhage H, Jaspers RT. Myotube growth is associated with cancer-like metabolic reprogramming and is limited by phosphoglycerate dehydrogenase. Exp Cell Res 2023; 433:113820. [PMID: 37879549 DOI: 10.1016/j.yexcr.2023.113820] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2022] [Revised: 10/10/2023] [Accepted: 10/14/2023] [Indexed: 10/27/2023]
Abstract
The Warburg effect links growth and glycolysis in cancer. A key purpose of the Warburg effect is to generate glycolytic intermediates for anabolic reactions, such as nucleotides → RNA/DNA and amino acids → protein synthesis. The aim of this study was to investigate whether a similar 'glycolysis-for-anabolism' metabolic reprogramming also occurs in hypertrophying skeletal muscle. To interrogate this, we first induced C2C12 myotube hypertrophy with IGF-1. We then added 14C glucose to the differentiation medium and measured radioactivity in isolated protein and RNA to establish whether 14C had entered anabolism. We found that especially protein became radioactive, suggesting a glucose → glycolytic intermediates → non-essential amino acid(s) → protein series of reactions, the rate of which was increased by IGF-1. Next, to investigate the importance of glycolytic flux and non-essential amino acid synthesis for myotube hypertrophy, we exposed C2C12 and primary mouse myotubes to the glycolysis inhibitor 2-Deoxy-d-glucose (2DG). We found that inhibiting glycolysis lowered C2C12 and primary myotube size. Similarly, siRNA silencing of PHGDH, the key enzyme of the serine biosynthesis pathway, decreased C2C12 and primary myotube size; whereas retroviral PHGDH overexpression increased C2C12 myotube size. Together these results suggest that glycolysis is important for hypertrophying myotubes, which reprogram their metabolism to facilitate anabolism, similar to cancer cells.
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Affiliation(s)
- Lian E M Stadhouders
- Laboratory for Myology, Department of Human Movement Sciences, Faculty of Behavioural and Movement Sciences, Vrije Universiteit Amsterdam, Amsterdam Movement Sciences, De Boelelaan 1108, 1081 HZ, Amsterdam, the Netherlands
| | - Jonathon A B Smith
- School of Medicine, Medical Sciences and Nutrition, University of Aberdeen, Foresterhill, Aberdeen, AB25 2ZD, UK; Department of Physiology and Pharmacology (FYFA), Group of Integrative Physiology, Karolinska Institutet, Stockholm, Sweden
| | - Brendan M Gabriel
- Aberdeen Cardiovascular & Diabetes Centre, The Rowett Institute, University of Aberdeen, Aberdeen, UK
| | - Sander A J Verbrugge
- Exercise Biology, Department for Sport and Health Sciences, Technical University of Munich, Georg-Brauchle-Ring 60/62, 80992, München/Munich, Germany
| | - Tim D Hammersen
- Laboratory for Myology, Department of Human Movement Sciences, Faculty of Behavioural and Movement Sciences, Vrije Universiteit Amsterdam, Amsterdam Movement Sciences, De Boelelaan 1108, 1081 HZ, Amsterdam, the Netherlands
| | - Detmar Kolijn
- Laboratory for Myology, Department of Human Movement Sciences, Faculty of Behavioural and Movement Sciences, Vrije Universiteit Amsterdam, Amsterdam Movement Sciences, De Boelelaan 1108, 1081 HZ, Amsterdam, the Netherlands; Department of Clinical Pharmacology and Molecular Cardiology, Ruhr University Bochum, Bochum, Germany
| | - Ilse S P Vogel
- Laboratory for Myology, Department of Human Movement Sciences, Faculty of Behavioural and Movement Sciences, Vrije Universiteit Amsterdam, Amsterdam Movement Sciences, De Boelelaan 1108, 1081 HZ, Amsterdam, the Netherlands
| | - Abdalla D Mohamed
- School of Medicine, Medical Sciences and Nutrition, University of Aberdeen, Foresterhill, Aberdeen, AB25 2ZD, UK; Cancer Therapeutics Unit, Target Genomic and Chromosomal Instability, The Institute of Cancer Research, 15 Cotswold Road, Sutton, London, SM2 5NG, UK
| | - Gerard M J de Wit
- Laboratory for Myology, Department of Human Movement Sciences, Faculty of Behavioural and Movement Sciences, Vrije Universiteit Amsterdam, Amsterdam Movement Sciences, De Boelelaan 1108, 1081 HZ, Amsterdam, the Netherlands
| | - Carla Offringa
- Laboratory for Myology, Department of Human Movement Sciences, Faculty of Behavioural and Movement Sciences, Vrije Universiteit Amsterdam, Amsterdam Movement Sciences, De Boelelaan 1108, 1081 HZ, Amsterdam, the Netherlands
| | - Willem M H Hoogaars
- Laboratory for Myology, Department of Human Movement Sciences, Faculty of Behavioural and Movement Sciences, Vrije Universiteit Amsterdam, Amsterdam Movement Sciences, De Boelelaan 1108, 1081 HZ, Amsterdam, the Netherlands
| | - Sebastian Gehlert
- Department for the Biosciences of Sports, Institute of Sports Science, University of Hildesheim, Universitätsplatz 1, 31141, Hildesheim, Germany; Department for Molecular and Cellular Sports Medicine, German Sport University Cologne, 50933, Cologne, Germany
| | - Henning Wackerhage
- Exercise Biology, Department for Sport and Health Sciences, Technical University of Munich, Georg-Brauchle-Ring 60/62, 80992, München/Munich, Germany
| | - Richard T Jaspers
- Laboratory for Myology, Department of Human Movement Sciences, Faculty of Behavioural and Movement Sciences, Vrije Universiteit Amsterdam, Amsterdam Movement Sciences, De Boelelaan 1108, 1081 HZ, Amsterdam, the Netherlands.
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Ismaeel A, Thomas NT, McCashland M, Vechetti IJ, Edman S, Lanner JT, Figueiredo VC, Fry CS, McCarthy JJ, Wen Y, Murach KA, von Walden F. Coordinated Regulation of Myonuclear DNA Methylation, mRNA, and miRNA Levels Associates With the Metabolic Response to Rapid Synergist Ablation-Induced Skeletal Muscle Hypertrophy in Female Mice. FUNCTION 2023; 5:zqad062. [PMID: 38020067 PMCID: PMC10666992 DOI: 10.1093/function/zqad062] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2023] [Revised: 10/16/2023] [Accepted: 11/01/2023] [Indexed: 12/01/2023] Open
Abstract
The central dogma of molecular biology dictates the general flow of molecular information from DNA that leads to a functional cellular outcome. In skeletal muscle fibers, the extent to which global myonuclear transcriptional alterations, accounting for epigenetic and post-transcriptional influences, contribute to an adaptive stress response is not clearly defined. In this investigation, we leveraged an integrated analysis of the myonucleus-specific DNA methylome and transcriptome, as well as myonuclear small RNA profiling to molecularly define the early phase of skeletal muscle fiber hypertrophy. The analysis of myonucleus-specific mature microRNA and other small RNA species provides new directions for exploring muscle adaptation and complemented the methylation and transcriptional information. Our integrated multi-omics interrogation revealed a coordinated myonuclear molecular landscape during muscle loading that coincides with an acute and rapid reduction of oxidative metabolism. This response may favor a biosynthesis-oriented metabolic program that supports rapid hypertrophic growth.
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Affiliation(s)
- Ahmed Ismaeel
- Department of Physiology, College of Medicine, University of Kentucky, Lexington, KY 40508, USA
- Center for Muscle Biology, University of Kentucky, Lexington, KY 40536, USA
| | - Nicholas T Thomas
- Center for Muscle Biology, University of Kentucky, Lexington, KY 40536, USA
- Department of Athletic Training and Clinical Nutrition, College of Health Sciences, University of Kentucky, Lexington, KY 40536, USA
| | - Mariah McCashland
- Department of Nutrition and Health Sciences, University of Nebraska–Lincoln, Lincoln, NE 68583, USA
| | - Ivan J Vechetti
- Department of Nutrition and Health Sciences, University of Nebraska–Lincoln, Lincoln, NE 68583, USA
| | - Sebastian Edman
- Department of Women’s and Children’s Health, Karolinska Institutet, Solna 17177, Sweden
| | - Johanna T Lanner
- Department of Physiology and Pharmacology, Karolinska Institutet, Solna 17177, Sweden
| | - Vandré C Figueiredo
- Department of Biological Sciences, Oakland University, Rochester, MI 48309, USA
| | - Christopher S Fry
- Center for Muscle Biology, University of Kentucky, Lexington, KY 40536, USA
- Department of Athletic Training and Clinical Nutrition, College of Health Sciences, University of Kentucky, Lexington, KY 40536, USA
| | - John J McCarthy
- Department of Physiology, College of Medicine, University of Kentucky, Lexington, KY 40508, USA
- Center for Muscle Biology, University of Kentucky, Lexington, KY 40536, USA
| | - Yuan Wen
- Department of Physiology, College of Medicine, University of Kentucky, Lexington, KY 40508, USA
- Center for Muscle Biology, University of Kentucky, Lexington, KY 40536, USA
- Division of Biomedical Informatics, Department of Internal Medicine, College of Medicine, University of Kentucky, Lexington, KY 40536, USA
| | - Kevin A Murach
- Department of Health, Human Performance, and Recreation, Exercise Science Research Center, University of Arkansas, Fayetteville, AR 72701, USA
| | - Ferdinand von Walden
- Department of Women’s and Children’s Health, Karolinska Institutet, Solna 17177, Sweden
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5
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Ismaeel A, Valentino TR, Burke B, Goh J, Saliu TP, Albathi F, Owen A, McCarthy JJ, Wen Y. Acetate and succinate benefit host muscle energetics as exercise-associated post-biotics. Physiol Rep 2023; 11:e15848. [PMID: 37940330 PMCID: PMC10632089 DOI: 10.14814/phy2.15848] [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: 10/13/2023] [Revised: 10/19/2023] [Accepted: 10/19/2023] [Indexed: 11/10/2023] Open
Abstract
Recently, the gut microbiome has emerged as a potent modulator of exercise-induced systemic adaptation and appears to be crucial for mediating some of the benefits of exercise. This study builds upon previous evidence establishing a gut microbiome-skeletal muscle axis, identifying exercise-induced changes in microbiome composition. Metagenomics sequencing of fecal samples from non-exercise-trained controls or exercise-trained mice was conducted. Biodiversity indices indicated exercise training did not change alpha diversity. However, there were notable differences in beta-diversity between trained and untrained microbiomes. Exercise significantly increased the level of the bacterial species Muribaculaceae bacterium DSM 103720. Computation simulation of bacterial growth was used to predict metabolites that accumulate under in silico culture of exercise-responsive bacteria. We identified acetate and succinate as potential gut microbial metabolites that are produced by Muribaculaceae bacterium, which were then administered to mice during a period of mechanical overload-induced muscle hypertrophy. Although no differences were observed for the overall muscle growth response to succinate or acetate administration during the first 5 days of mechanical overload-induced hypertrophy, acetate and succinate increased skeletal muscle mitochondrial respiration. When given as post-biotics, succinate or acetate treatment may improve oxidative metabolism during muscle hypertrophy.
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Affiliation(s)
- Ahmed Ismaeel
- Department of Physiology, College of MedicineUniversity of KentuckyLexingtonKentuckyUSA
- Center for Muscle BiologyUniversity of KentuckyLexingtonKentuckyUSA
| | | | - Benjamin Burke
- Department of Physiology, College of MedicineUniversity of KentuckyLexingtonKentuckyUSA
- Center for Muscle BiologyUniversity of KentuckyLexingtonKentuckyUSA
| | - Jensen Goh
- Department of Physiology, College of MedicineUniversity of KentuckyLexingtonKentuckyUSA
- Center for Muscle BiologyUniversity of KentuckyLexingtonKentuckyUSA
| | - Tolulope P. Saliu
- Department of Physiology, College of MedicineUniversity of KentuckyLexingtonKentuckyUSA
- Center for Muscle BiologyUniversity of KentuckyLexingtonKentuckyUSA
| | - Fatmah Albathi
- Department of Pharmacology and Nutritional Sciences, College of MedicineUniversity of KentuckyLexingtonKentuckyUSA
| | - Allison Owen
- Center for Muscle BiologyUniversity of KentuckyLexingtonKentuckyUSA
- Department of Athletic TrainingCollege of Health SciencesUniversity of KentuckyLexingtonKentuckyUSA
| | - John J. McCarthy
- Department of Physiology, College of MedicineUniversity of KentuckyLexingtonKentuckyUSA
- Center for Muscle BiologyUniversity of KentuckyLexingtonKentuckyUSA
| | - Yuan Wen
- Department of Physiology, College of MedicineUniversity of KentuckyLexingtonKentuckyUSA
- Center for Muscle BiologyUniversity of KentuckyLexingtonKentuckyUSA
- Division of Biomedical Informatics, Department of Internal Medicine, College of MedicineUniversity of KentuckyLexingtonKentuckyUSA
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6
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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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7
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Vanmunster M, Rojo-Garcia AV, Pacolet A, Jonkers I, Koppo K, Lories R, Suhr F. Prolonged mechanical muscle loading increases mechanosensor gene and protein levels and causes a moderate fast-to-slow fiber type switch in mice. J Appl Physiol (1985) 2023; 135:918-931. [PMID: 37675473 DOI: 10.1152/japplphysiol.00204.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2023] [Revised: 08/30/2023] [Accepted: 08/30/2023] [Indexed: 09/08/2023] Open
Abstract
Mechanosensing and subsequent mechanotransduction are indispensable for muscle plasticity. Nevertheless, a scarcity of literature exists regarding an all-encompassing understanding of the muscle mechanosensing machinery's response to prolonged loading, especially in conditions that resemble a natural physiological state of skeletal muscle. This study aimed to comprehensively explore the effects of prolonged mechanical loading on mechanosensitive components, skeletal muscle characteristics, and metabolism-related gene clusters. Twenty male C57BL/6J mice were randomly divided into two groups: control and prolonged mechanical loading. To induce prolonged mechanical loading on the triceps brachii (TRI) and biceps brachii (BIC) muscles, a 14-day period of tail suspension was implemented. In TRI only, prolonged mechanical loading caused a mild fast-to-slow fiber type shift together with increased mechanosensor gene and protein levels. It also increased transcription factors associated with slow muscle fibers while decreasing those related to fast-type muscle gene expression. Succinate dehydrogenase activity, a marker of muscle oxidative capacity, and genes involved in oxidative and mitochondrial turnover increased, whereas glycolytic-related genes decreased. Moreover, prolonged mechanical loading stimulated markers of muscle protein synthesis. Taken together, our data show a collective muscle-specific increase in mechanosensor gene and protein levels upon a period of prolonged mechanical loading in conditions that reflect a more natural physiological state of skeletal muscle in mice. We provide additional proof-of-concept that prolonged tail suspension-induced loading of the forelimbs triggers a muscle-specific fast-to-slow fiber type switch, and this coincides with increased protein synthesis-related signaling.NEW & NOTEWORTHY This study provides a comprehensive overview of the effects of prolonged loading on mechanosensitive components in conditions that better reflect the natural physiological state of skeletal muscle. Although the muscle mechanosensing machinery has been widely acknowledged for its responsiveness to altered loading, an inclusive understanding of its response to prolonged loading remains scarce. Our results show a fast-to-slow fiber type shift and an upregulation of mechanosensor gene and protein levels following prolonged loading.
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Affiliation(s)
- Mathias Vanmunster
- Department of Movement Sciences, Exercise Physiology Research Group, KU Leuven, Leuven, Belgium
| | | | - Alexander Pacolet
- Department of Movement Sciences, Exercise Physiology Research Group, KU Leuven, Leuven, Belgium
| | - Ilse Jonkers
- Department of Movement Sciences, Human Movement Biomechanics Research Group, KU Leuven, Leuven, Belgium
| | - Katrien Koppo
- Department of Movement Sciences, Exercise Physiology Research Group, KU Leuven, Leuven, Belgium
| | - Rik Lories
- Department of Development and Regeneration, Skeletal Biology and Engineering Research Center, KU Leuven, Leuven, Belgium
| | - Frank Suhr
- Department of Movement Sciences, Exercise Physiology Research Group, KU Leuven, Leuven, Belgium
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8
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Pierre A, Bourel C, Favory R, Brassart B, Wallet F, Daussin FN, Normandin S, Howsam M, Romien R, Lemaire J, Grolaux G, Durand A, Frimat M, Bastide B, Amouyel P, Boulanger E, Preau S, Lancel S. Sepsis-like Energy Deficit Is Not Sufficient to Induce Early Muscle Fiber Atrophy and Mitochondrial Dysfunction in a Murine Sepsis Model. BIOLOGY 2023; 12:biology12040529. [PMID: 37106730 PMCID: PMC10136327 DOI: 10.3390/biology12040529] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/22/2022] [Revised: 03/17/2023] [Accepted: 03/29/2023] [Indexed: 04/03/2023]
Abstract
Sepsis-induced myopathy is characterized by muscle fiber atrophy, mitochondrial dysfunction, and worsened outcomes. Whether whole-body energy deficit participates in the early alteration of skeletal muscle metabolism has never been investigated. Three groups were studied: “Sepsis” mice, fed ad libitum with a spontaneous decrease in caloric intake (n = 17), and “Sham” mice fed ad libitum (Sham fed (SF), n = 13) or subjected to pair-feeding (Sham pair fed (SPF), n = 12). Sepsis was induced by the intraperitoneal injection of cecal slurry in resuscitated C57BL6/J mice. The feeding of the SPF mice was restricted according to the food intake of the Sepsis mice. Energy balance was evaluated by indirect calorimetry over 24 h. The tibialis anterior cross-sectional area (TA CSA), mitochondrial function (high-resolution respirometry), and mitochondrial quality control pathways (RTqPCR and Western blot) were assessed 24 h after sepsis induction. The energy balance was positive in the SF group and negative in both the SPF and Sepsis groups. The TA CSA did not differ between the SF and SPF groups, but was reduced by 17% in the Sepsis group compared with the SPF group (p < 0.05). The complex-I-linked respiration in permeabilized soleus fibers was higher in the SPF group than the SF group (p < 0.05) and lower in the Sepsis group than the SPF group (p < 0.01). Pgc1α protein expression increased 3.9-fold in the SPF mice compared with the SF mice (p < 0.05) and remained unchanged in the Sepsis mice compared with the SPF mice; the Pgc1α mRNA expression decreased in the Sepsis compared with the SPF mice (p < 0.05). Thus, the sepsis-like energy deficit did not explain the early sepsis-induced muscle fiber atrophy and mitochondrial dysfunction, but led to specific metabolic adaptations not observed in sepsis.
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9
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Smith MA, Sexton CL, Smith KA, Osburn SC, Godwin JS, Beausejour JP, Ruple BA, Goodlett MD, Edison JL, Fruge AD, Robinson AT, Gladden LB, Young KC, Roberts MD. Molecular predictors of resistance training outcomes in young untrained female adults. J Appl Physiol (1985) 2023; 134:491-507. [PMID: 36633866 PMCID: PMC10190845 DOI: 10.1152/japplphysiol.00605.2022] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2022] [Revised: 01/10/2023] [Accepted: 01/10/2023] [Indexed: 01/13/2023] Open
Abstract
We sought to determine if the myofibrillar protein synthetic (MyoPS) response to a naïve resistance exercise (RE) bout, or chronic changes in satellite cell number and muscle ribosome content, were associated with hypertrophic outcomes in females or differed in those who classified as higher (HR) or lower (LR) responders to resistance training (RT). Thirty-four untrained college-aged females (23.4 ± 3.4 kg/m2) completed a 10-wk RT protocol (twice weekly). Body composition and leg imaging assessments, a right leg vastus lateralis biopsy, and strength testing occurred before and following the intervention. A composite score, which included changes in whole body lean/soft tissue mass (LSTM), vastus lateralis (VL) muscle cross-sectional area (mCSA), midthigh mCSA, and deadlift strength, was used to delineate upper and lower HR (n = 8) and LR (n = 8) quartiles. In all participants, training significantly (P < 0.05) increased LSTM, VL mCSA, midthigh mCSA, deadlift strength, mean muscle fiber cross-sectional area, satellite cell abundance, and myonuclear number. Increases in LSTM (P < 0.001), VL mCSA (P < 0.001), midthigh mCSA (P < 0.001), and deadlift strength (P = 0.001) were greater in HR vs. LR. The first-bout 24-hour MyoPS response was similar between HR and LR (P = 0.367). While no significant responder × time interaction existed for muscle total RNA concentrations (i.e., ribosome content) (P = 0.888), satellite cell abundance increased in HR (P = 0.026) but not LR (P = 0.628). Pretraining LSTM (P = 0.010), VL mCSA (P = 0.028), and midthigh mCSA (P < 0.001) were also greater in HR vs. LR. Female participants with an enhanced satellite cell response to RT, and more muscle mass before RT, exhibited favorable resistance training adaptations.NEW & NOTEWORTHY This study continues to delineate muscle biology differences between lower and higher responders to resistance training and is unique in that a female population was interrogated. As has been reported in prior studies, increases in satellite cell numbers are related to positive responses to resistance training. Satellite cell responsivity, rather than changes in muscle ribosome content per milligrams of tissue, may be a more important factor in delineating resistance-training responses in women.
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Affiliation(s)
- Morgan A Smith
- School of Kinesiology, Auburn University, Auburn, Alabama
| | - Casey L Sexton
- School of Kinesiology, Auburn University, Auburn, Alabama
| | - Kristen A Smith
- Department of Nutrition, Dietetics and Hospitality Management, Auburn University, Auburn, Alabama
| | | | | | | | | | - Michael D Goodlett
- Athletics Department, Auburn University, Auburn, Alabama
- Edward Via College of Osteopathic Medicine, Auburn, Alabama
| | - Joseph L Edison
- Athletics Department, Auburn University, Auburn, Alabama
- Edward Via College of Osteopathic Medicine, Auburn, Alabama
| | - Andrew D Fruge
- Department of Nutrition, Dietetics and Hospitality Management, Auburn University, Auburn, Alabama
- College of Nursing, Auburn University, Auburn, Alabama
| | | | | | - Kaelin C Young
- School of Kinesiology, Auburn University, Auburn, Alabama
- Edward Via College of Osteopathic Medicine, Auburn, Alabama
| | - Michael D Roberts
- School of Kinesiology, Auburn University, Auburn, Alabama
- Edward Via College of Osteopathic Medicine, Auburn, Alabama
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10
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Viggars MR, Owens DJ, Stewart C, Coirault C, Mackey AL, Jarvis JC. PCM1 labeling reveals myonuclear and nuclear dynamics in skeletal muscle across species. Am J Physiol Cell Physiol 2023; 324:C85-C97. [PMID: 36409178 DOI: 10.1152/ajpcell.00285.2022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Myonuclei transcriptionally regulate muscle fibers during homeostasis and adaptation to exercise. Their subcellular location and quantity are important when characterizing phenotypes of myopathies, the effect of treatments, and understanding the roles of satellite cells in muscle adaptation and muscle "memory." Difficulties arise in identifying myonuclei due to their proximity to the sarcolemma and closely residing interstitial cell neighbors. We aimed to determine to what extent (pericentriolar material-1) PCM1 is a specific marker of myonuclei in vitro and in vivo. Single isolated myofibers and cross sections from mice and humans were studied from several models including wild-type and Lamin A/C mutant mice after functional overload and damage and recovery in humans following forced eccentric contractions. Fibers were immunolabeled for PCM1, Pax7, and DNA. C2C12 myoblasts were also studied to investigate changes in PCM1 localization during myogenesis. PCM1 was detected at not only the nuclear envelope of myonuclei in mature myofibers and in newly formed myotubes but also centrosomes in proliferating myogenic precursors, which may or may not fuse to join the myofiber syncytium. PCM1 was also detected in nonmyogenic nuclei near the sarcolemma, especially in regenerating areas of the Lmna+/ΔK32 mouse and damaged human muscle. Although PCM1 is not completely specific to myonuclei, the impact that PCM1+ macrophages and interstitial cells have on myonuclei counts would be small in healthy muscle. PCM1 may prove useful as a marker of satellite cell dynamics due to the distinct change in localization during differentiation, revealing satellite cells in their quiescent (PCM1-), proliferating (PCM1+ centrosome), and prefusion states (PCM1+ nuclear envelope).
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Affiliation(s)
- Mark R Viggars
- Research Institute for Sport and Exercise Sciences, Liverpool John Moores University, Liverpool, United Kingdom.,Department of Physiology and Aging, University of Florida, Gainesville, Florida.,Myology Institute, University of Florida, Gainesville, Florida
| | - Daniel J Owens
- Research Institute for Sport and Exercise Sciences, Liverpool John Moores University, Liverpool, United Kingdom.,Sorbonne Université, INSERM, Myology Research Center, Paris, France
| | - Claire Stewart
- Research Institute for Sport and Exercise Sciences, Liverpool John Moores University, Liverpool, United Kingdom
| | | | - Abigail L Mackey
- Department of Orthopaedic Surgery, Institute of Sports Medicine Copenhagen, Copenhagen University Hospital - Bispebjerg and Frederiksberg, Copenhagen, Denmark.,Department of Biomedical Sciences, Faculty of Health and Medical Sciences, Center for Healthy Aging, Xlab, University of Copenhagen, Copenhagen, Denmark.,Department of Clinical Medicine, University of Copenhagen, Copenhagen, Denmark
| | - Jonathan C Jarvis
- Research Institute for Sport and Exercise Sciences, Liverpool John Moores University, Liverpool, United Kingdom
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11
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Identification of key adipogenic transcription factors for the pork belly parameters via the association weight matrix. Meat Sci 2023; 195:109015. [DOI: 10.1016/j.meatsci.2022.109015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2022] [Revised: 10/18/2022] [Accepted: 10/18/2022] [Indexed: 11/09/2022]
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12
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Viggars MR, Sutherland H, Lanmüller H, Schmoll M, Bijak M, Jarvis JC. Adaptation of the transcriptional response to resistance exercise over 4 weeks of daily training. FASEB J 2023; 37:e22686. [PMID: 36468768 DOI: 10.1096/fj.202201418r] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2022] [Revised: 11/05/2022] [Accepted: 11/21/2022] [Indexed: 12/12/2022]
Abstract
We present the time course of change in the muscle transcriptome 1 h after the last exercise bout of a daily resistance training program lasting 2, 10, 20, or 30 days. Daily exercise in rat tibialis anterior muscles (5 sets of 10 repetitions over 20 min) induced progressive muscle growth that approached a new stable state after 30 days. The acute transcriptional response changed along with progressive adaptation of the muscle phenotype. For example, expression of type 2B myosin was silenced. Time courses recently synthesized from human exercise studies do not demonstrate so clearly the interplay between the acute exercise response and the longer-term consequences of repeated exercise. We highlight classes of transcripts and transcription factors whose expression increases during the growth phase and declines again as the muscle adapts to a new daily pattern of activity and reduces its rate of growth. Myc appears to play a central role.
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Affiliation(s)
- Mark R Viggars
- Research Institute for Sport & Exercise Sciences, Liverpool John Moores University, Liverpool, UK.,Department of Physiology and Aging, University of Florida, Gainesville, Florida, USA.,Myology Institute, University of Florida, Gainesville, Florida, USA
| | - Hazel Sutherland
- Research Institute for Sport & Exercise Sciences, Liverpool John Moores University, Liverpool, UK
| | - Hermann Lanmüller
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria
| | - Martin Schmoll
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria
| | - Manfred Bijak
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria
| | - Jonathan C Jarvis
- Research Institute for Sport & Exercise Sciences, Liverpool John Moores University, Liverpool, UK
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13
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Going nuclear: Molecular adaptations to exercise mediated by myonuclei. SPORTS MEDICINE AND HEALTH SCIENCE 2022; 5:2-9. [PMID: 36994170 PMCID: PMC10040379 DOI: 10.1016/j.smhs.2022.11.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2022] [Revised: 11/23/2022] [Accepted: 11/30/2022] [Indexed: 12/13/2022] Open
Abstract
Muscle fibers are multinucleated, and muscle fiber nuclei (myonuclei) are believed to be post-mitotic and are typically situated near the periphery of the myofiber. Due to the unique organization of muscle fibers and their nuclei, the cellular and molecular mechanisms regulating myofiber homeostasis in unstressed and stressed conditions (e.g., exercise) are unique. A key role myonuclei play in regulating muscle during exercise is gene transcription. Only recently have investigators had the capability to identify molecular changes at high resolution exclusively in myonuclei in response to perturbations in vivo. The purpose of this review is to describe how myonuclei modulate their transcriptome, epigenetic status, mobility and shape, and microRNA expression in response to exercise in vivo. Given the relative paucity of high-fidelity information on myonucleus-specific contributions to exercise adaptation, we identify specific gaps in knowledge and provide perspectives on future directions of research.
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14
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McMillin SL, Evans PL, Taylor WM, Weyrauch LA, Sermersheim TJ, Welc SS, Heitmeier MR, Hresko RC, Hruz PW, Koumanov F, Holman GD, Abel ED, Witczak CA. Muscle-Specific Ablation of Glucose Transporter 1 (GLUT1) Does Not Impair Basal or Overload-Stimulated Skeletal Muscle Glucose Uptake. Biomolecules 2022; 12:biom12121734. [PMID: 36551162 PMCID: PMC9776291 DOI: 10.3390/biom12121734] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2022] [Revised: 11/18/2022] [Accepted: 11/21/2022] [Indexed: 11/24/2022] Open
Abstract
Glucose transporter 1 (GLUT1) is believed to solely mediate basal (insulin-independent) glucose uptake in skeletal muscle; yet recent work has demonstrated that mechanical overload, a model of resistance exercise training, increases muscle GLUT1 levels. The primary objective of this study was to determine if GLUT1 is necessary for basal or overload-stimulated muscle glucose uptake. Muscle-specific GLUT1 knockout (mGLUT1KO) mice were generated and examined for changes in body weight, body composition, metabolism, systemic glucose regulation, muscle glucose transporters, and muscle [3H]-2-deoxyglucose uptake ± the GLUT1 inhibitor BAY-876. [3H]-hexose uptake ± BAY-876 was also examined in HEK293 cells-expressing GLUT1-6 or GLUT10. mGLUT1KO mice exhibited no impairments in body weight, lean mass, whole body metabolism, glucose tolerance, basal or overload-stimulated muscle glucose uptake. There was no compensation by the insulin-responsive GLUT4. In mGLUT1KO mouse muscles, overload stimulated higher expression of mechanosensitive GLUT6, but not GLUT3 or GLUT10. In control and mGLUT1KO mouse muscles, 0.05 µM BAY-876 impaired overload-stimulated, but not basal glucose uptake. In the GLUT-HEK293 cells, BAY-876 inhibited glucose uptake via GLUT1, GLUT3, GLUT4, GLUT6, and GLUT10. Collectively, these findings demonstrate that GLUT1 does not mediate basal muscle glucose uptake and suggest that a novel glucose transport mechanism mediates overload-stimulated glucose uptake.
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Affiliation(s)
- Shawna L. McMillin
- Departments of Kinesiology, Biochemistry & Molecular Biology, and Physiology, Brody School of Medicine, East Carolina Diabetes & Obesity Institute, East Carolina University, Greenville, NC 27858, USA
| | - Parker L. Evans
- Departments of Kinesiology, Biochemistry & Molecular Biology, and Physiology, Brody School of Medicine, East Carolina Diabetes & Obesity Institute, East Carolina University, Greenville, NC 27858, USA
| | - William M. Taylor
- Departments of Kinesiology, Biochemistry & Molecular Biology, and Physiology, Brody School of Medicine, East Carolina Diabetes & Obesity Institute, East Carolina University, Greenville, NC 27858, USA
| | - Luke A. Weyrauch
- Departments of Kinesiology, Biochemistry & Molecular Biology, and Physiology, Brody School of Medicine, East Carolina Diabetes & Obesity Institute, East Carolina University, Greenville, NC 27858, USA
| | - Tyler J. Sermersheim
- Department of Anatomy, Cell Biology & Physiology, and Indiana Center for Musculoskeletal Health, Indiana University School of Medicine, Indianapolis, IN 46202, USA
- Indiana Center for Diabetes & Metabolic Diseases, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | - Steven S. Welc
- Department of Anatomy, Cell Biology & Physiology, and Indiana Center for Musculoskeletal Health, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | - Monique R. Heitmeier
- Departments of Pediatrics, and Cell Biology and Physiology, Washington University School of Medicine, St. Louis, MO 63130, USA
| | - Richard C. Hresko
- Departments of Pediatrics, and Cell Biology and Physiology, Washington University School of Medicine, St. Louis, MO 63130, USA
| | - Paul W. Hruz
- Departments of Pediatrics, and Cell Biology and Physiology, Washington University School of Medicine, St. Louis, MO 63130, USA
| | | | - Geoffrey D. Holman
- Department of Biology and Biochemistry, University of Bath, Bath BA2 7AY, UK
| | - E. Dale Abel
- Fraternal Order of Eagles Diabetes Research Center, Division of Endocrinology & Metabolism, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA
| | - Carol A. Witczak
- Departments of Kinesiology, Biochemistry & Molecular Biology, and Physiology, Brody School of Medicine, East Carolina Diabetes & Obesity Institute, East Carolina University, Greenville, NC 27858, USA
- Department of Anatomy, Cell Biology & Physiology, and Indiana Center for Musculoskeletal Health, Indiana University School of Medicine, Indianapolis, IN 46202, USA
- Indiana Center for Diabetes & Metabolic Diseases, Indiana University School of Medicine, Indianapolis, IN 46202, USA
- Correspondence:
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15
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Murach KA, Liu Z, Jude B, Figueiredo VC, Wen Y, Khadgi S, Lim S, Morena da Silva F, Greene NP, Lanner JT, McCarthy JJ, Vechetti IJ, von Walden F. Multi-transcriptome analysis following an acute skeletal muscle growth stimulus yields tools for discerning global and MYC regulatory networks. J Biol Chem 2022; 298:102515. [PMID: 36150502 PMCID: PMC9583450 DOI: 10.1016/j.jbc.2022.102515] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2022] [Revised: 09/15/2022] [Accepted: 09/17/2022] [Indexed: 02/01/2023] Open
Abstract
Myc is a powerful transcription factor implicated in epigenetic reprogramming, cellular plasticity, and rapid growth as well as tumorigenesis. Cancer in skeletal muscle is extremely rare despite marked and sustained Myc induction during loading-induced hypertrophy. Here, we investigated global, actively transcribed, stable, and myonucleus-specific transcriptomes following an acute hypertrophic stimulus in mouse plantaris. With these datasets, we define global and Myc-specific dynamics at the onset of mechanical overload-induced muscle fiber growth. Data collation across analyses reveals an under-appreciated role for the muscle fiber in extracellular matrix remodeling during adaptation, along with the contribution of mRNA stability to epigenetic-related transcript levels in muscle. We also identify Runx1 and Ankrd1 (Marp1) as abundant myonucleus-enriched loading-induced genes. We observed that a strong induction of cell cycle regulators including Myc occurs with mechanical overload in myonuclei. Additionally, in vivo Myc-controlled gene expression in the plantaris was defined using a genetic muscle fiber-specific doxycycline-inducible Myc-overexpression model. We determined Myc is implicated in numerous aspects of gene expression during early-phase muscle fiber growth. Specifically, brief induction of Myc protein in muscle represses Reverbα, Reverbβ, and Myh2 while increasing Rpl3, recapitulating gene expression in myonuclei during acute overload. Experimental, comparative, and in silico analyses place Myc at the center of a stable and actively transcribed, loading-responsive, muscle fiber-localized regulatory hub. Collectively, our experiments are a roadmap for understanding global and Myc-mediated transcriptional networks that regulate rapid remodeling in postmitotic cells. We provide open webtools for exploring the five RNA-seq datasets as a resource to the field.
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Affiliation(s)
- Kevin A. Murach
- Department of Health, Human Performance, and Recreation, Exercise Science Research Center, University of Arkansas, Fayetteville, Arkansas, USA,Cell and Molecular Biology Graduate Program, University of Arkansas, Fayetteville, Arkansas, USA,For correspondence: Kevin A. Murach; Ivan J. Vechetti; Ferdinand von Walden
| | - Zhengye Liu
- Department of Physiology and Pharmacology, Karolinska Institute, Solna, Sweden
| | - Baptiste Jude
- Department of Physiology and Pharmacology, Karolinska Institute, Solna, Sweden,Department of Women’s and Children’s Health, Karolinska Institute, Solna, Sweden
| | - Vandre C. Figueiredo
- Center for Muscle Biology, University of Kentucky, Lexington, Kentucky, USA,Department of Physiology, University of Kentucky, Lexington, Kentucky, USA
| | - Yuan Wen
- Center for Muscle Biology, University of Kentucky, Lexington, Kentucky, USA,Department of Physical Therapy, University of Kentucky, Lexington, Kentucky, USA
| | - Sabin Khadgi
- Department of Health, Human Performance, and Recreation, Exercise Science Research Center, University of Arkansas, Fayetteville, Arkansas, USA
| | - Seongkyun Lim
- Department of Health, Human Performance, and Recreation, Exercise Science Research Center, University of Arkansas, Fayetteville, Arkansas, USA,Cachexia Research Laboratory, University of Arkansas, Fayetteville, Arkansas, USA
| | - Francielly Morena da Silva
- Department of Health, Human Performance, and Recreation, Exercise Science Research Center, University of Arkansas, Fayetteville, Arkansas, USA,Cachexia Research Laboratory, University of Arkansas, Fayetteville, Arkansas, USA
| | - Nicholas P. Greene
- Department of Health, Human Performance, and Recreation, Exercise Science Research Center, University of Arkansas, Fayetteville, Arkansas, USA,Cell and Molecular Biology Graduate Program, University of Arkansas, Fayetteville, Arkansas, USA,Cachexia Research Laboratory, University of Arkansas, Fayetteville, Arkansas, USA
| | - Johanna T. Lanner
- Department of Physiology and Pharmacology, Karolinska Institute, Solna, Sweden
| | - John J. McCarthy
- Center for Muscle Biology, University of Kentucky, Lexington, Kentucky, USA,Department of Physiology, University of Kentucky, Lexington, Kentucky, USA
| | - Ivan J. Vechetti
- Department of Nutrition and Health Sciences, University of Nebraska-Lincoln, Nebraska, USA,For correspondence: Kevin A. Murach; Ivan J. Vechetti; Ferdinand von Walden
| | - Ferdinand von Walden
- Department of Women’s and Children’s Health, Karolinska Institute, Solna, Sweden,For correspondence: Kevin A. Murach; Ivan J. Vechetti; Ferdinand von Walden
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16
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Brightwell CR, Latham CM, Thomas NT, Keeble AR, Murach KA, Fry CS. A glitch in the matrix: the pivotal role for extracellular matrix remodeling during muscle hypertrophy. Am J Physiol Cell Physiol 2022; 323:C763-C771. [PMID: 35876284 PMCID: PMC9448331 DOI: 10.1152/ajpcell.00200.2022] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2022] [Revised: 07/21/2022] [Accepted: 07/21/2022] [Indexed: 01/18/2023]
Abstract
Multinuclear muscle fibers are the most voluminous cells in skeletal muscle and the primary drivers of growth in response to loading. Outside the muscle fiber, however, is a diversity of mononuclear cell types that reside in the extracellular matrix (ECM). These muscle-resident cells are exercise-responsive and produce the scaffolding for successful myofibrillar growth. Without proper remodeling and maintenance of this ECM scaffolding, the ability to mount an appropriate response to resistance training in adult muscles is severely hindered. Complex cellular choreography takes place in muscles following a loading stimulus. These interactions have been recently revealed by single-cell explorations into muscle adaptation with loading. The intricate ballet of ECM remodeling involves collagen production from fibrogenic cells and ECM modifying signals initiated by satellite cells, immune cells, and the muscle fibers themselves. The acellular collagen-rich ECM is also a mechanical signal-transducer and rich repository of growth factors that may directly influence muscle fiber hypertrophy once liberated. Collectively, high levels of collagen expression, deposition, and turnover characterize a well-trained muscle phenotype. The purpose of this review is to highlight the most recent evidence for how the ECM and its cellular components affect loading-induced muscle hypertrophy. We also address how the muscle fiber may directly take part in ECM remodeling, and whether ECM dynamics are rate limiting for muscle fiber growth.
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Affiliation(s)
- Camille R Brightwell
- Center for Muscle Biology, University of Kentucky, Lexington, Kentucky
- Department of Athletic Training and Clinical Nutrition, College of Health Sciences, University of Kentucky, Lexington, Kentucky
| | - Christine M Latham
- Center for Muscle Biology, University of Kentucky, Lexington, Kentucky
- Department of Athletic Training and Clinical Nutrition, College of Health Sciences, University of Kentucky, Lexington, Kentucky
| | - Nicholas T Thomas
- Center for Muscle Biology, University of Kentucky, Lexington, Kentucky
- Department of Athletic Training and Clinical Nutrition, College of Health Sciences, University of Kentucky, Lexington, Kentucky
| | - Alexander R Keeble
- Center for Muscle Biology, University of Kentucky, Lexington, Kentucky
- Department of Athletic Training and Clinical Nutrition, College of Health Sciences, University of Kentucky, Lexington, Kentucky
| | - Kevin A Murach
- Department of Health, Human Performance, and Recreation, Molecular Muscle Mass Regulation Laboratory, Exercise Science Research Center, University of Arkansas, Fayetteville, Arkansas
- Cell and Molecular Biology Graduate Program, University of Arkansas, Fayetteville, Arkansas
| | - Christopher S Fry
- Center for Muscle Biology, University of Kentucky, Lexington, Kentucky
- Department of Athletic Training and Clinical Nutrition, College of Health Sciences, University of Kentucky, Lexington, Kentucky
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17
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Dungan CM, Figueiredo VC, Wen Y, VonLehmden GL, Zdunek CJ, Thomas NT, Mobley CB, Murach KA, Brightwell CR, Long DE, Fry CS, Kern PA, McCarthy JJ, Peterson CA. Senolytic treatment rescues blunted muscle hypertrophy in old mice. GeroScience 2022; 44:1925-1940. [PMID: 35325353 PMCID: PMC9616988 DOI: 10.1007/s11357-022-00542-2] [Citation(s) in RCA: 21] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2021] [Accepted: 03/06/2022] [Indexed: 01/07/2023] Open
Abstract
With aging, skeletal muscle plasticity is attenuated in response to exercise. Here, we report that senescent cells, identified using senescence-associated β-galactosidase (SA β-Gal) activity and p21 immunohistochemistry, are very infrequent in resting muscle, but emerge approximately 2 weeks after a bout of resistance exercise in humans. We hypothesized that these cells contribute to blunted hypertrophic potential in old age. Using synergist ablation-induced mechanical overload (MOV) of the plantaris muscle to model resistance training in adult (5-6-month) and old (23-24-month) male C57BL/6 J mice, we found increased senescent cells in both age groups during hypertrophy. Consistent with the human data, there were negligible senescent cells in plantaris muscle from adult and old sham controls, but old mice had significantly more senescent cells 7 and 14 days following MOV relative to young. Old mice had blunted whole-muscle hypertrophy when compared to adult mice, along with smaller muscle fibers, specifically glycolytic type 2x + 2b fibers. To ablate senescent cells using a hit-and-run approach, old mice were treated with vehicle or a senolytic cocktail consisting of 5 mg/kg dasatinib and 50 mg/kg quercetin (D + Q) on days 7 and 10 during 14 days of MOV; control mice underwent sham surgery with or without senolytic treatment. Old mice given D + Q had larger muscles and muscle fibers after 14 days of MOV, fewer senescent cells when compared to vehicle-treated old mice, and changes in the expression of genes (i.e., Igf1, Ddit4, Mmp14) that are associated with hypertrophic growth. Our data collectively show that senescent cells emerge in human and mouse skeletal muscle following a hypertrophic stimulus and that D + Q improves muscle growth in old mice.
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Affiliation(s)
- Cory M Dungan
- Center for Muscle Biology, University of Kentucky, Lexington, KY, USA.
- Department of Physical Therapy, University of Kentucky, Lexington, KY, USA.
- College of Health Sciences, University of Kentucky, 900 S. Limestone, CTW 445, Lexington, KY, 40536, USA.
| | | | - Yuan Wen
- Center for Muscle Biology, University of Kentucky, Lexington, KY, USA
- Department of Physical Therapy, University of Kentucky, Lexington, KY, USA
| | | | | | - Nicholas T Thomas
- Center for Muscle Biology, University of Kentucky, Lexington, KY, USA
- Department of Athletic Training and Clinical Nutrition, University of Kentucky, Lexington, KY, USA
| | - C Brooks Mobley
- Center for Muscle Biology, University of Kentucky, Lexington, KY, USA
- Department of Physiology, University of Kentucky, Lexington, KY, USA
- School of Kinesiology, Auburn University, Auburn, AL, USA
| | - Kevin A Murach
- Center for Muscle Biology, University of Kentucky, Lexington, KY, USA
- Department of Health, Human Performance, and Recreation, University of Arkansas, Fayetteville, AR, USA
| | - Camille R Brightwell
- Center for Muscle Biology, University of Kentucky, Lexington, KY, USA
- Department of Athletic Training and Clinical Nutrition, University of Kentucky, Lexington, KY, USA
| | - Douglas E Long
- Center for Muscle Biology, University of Kentucky, Lexington, KY, USA
- Department of Physical Therapy, University of Kentucky, Lexington, KY, USA
| | - Christopher S Fry
- Center for Muscle Biology, University of Kentucky, Lexington, KY, USA
- Department of Athletic Training and Clinical Nutrition, University of Kentucky, Lexington, KY, USA
| | - Philip A Kern
- Department of Internal Medicine, Division of Endocrinology, University of Kentucky, Lexington, KY, USA
| | - John J McCarthy
- Center for Muscle Biology, University of Kentucky, Lexington, KY, USA
- Department of Physiology, University of Kentucky, Lexington, KY, USA
| | - Charlotte A Peterson
- Center for Muscle Biology, University of Kentucky, Lexington, KY, USA
- Department of Physical Therapy, University of Kentucky, Lexington, KY, USA
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18
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Skeletal muscle phenotyping of Hippo gene-mutated mice reveals that Lats1 deletion increases the percentage of type I muscle fibers. Transgenic Res 2022; 31:227-237. [PMID: 34984591 PMCID: PMC8993742 DOI: 10.1007/s11248-021-00293-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2021] [Accepted: 12/02/2021] [Indexed: 12/04/2022]
Abstract
The Hippo signal transduction network regulates transcription through Yap/Taz-Tead1-4 in many tissues including skeletal muscle. Whilst transgenic mice have been generated for many Hippo genes, the resultant skeletal muscle phenotypes were not always characterized. Here, we aimed to phenotype the hindlimb muscles of Hippo gene-mutated Lats1−/−, Mst2−/−, Vgll3−/−, and Vgll4+/− mice. This analysis revealed that Lats1−/− mice have 11% more slow type I fibers than age and sex-matched wild-type controls. Moreover, the mRNA expression of slow Myh7 increased by 50%, and the concentration of type I myosin heavy chain is 80% higher in Lats1−/− mice than in age and sex-matched wild-type controls. Second, to find out whether exercise-related stimuli affect Lats1, we stimulated C2C12 myotubes with the hypertrophy agent clenbuterol or the energy stress agent AICAR. We found that both stimulated Lats1 expression by 1.2 and 1.3 fold respectively. Third, we re-analyzed published datasets and found that Lats1 mRNA in muscle is 63% higher in muscular dystrophy, increases by 17–77% after cardiotoxin-induced muscle injury, by 41–71% in muscles during overload-induced hypertrophy, and by 19–21% after endurance exercise when compared to respective controls. To conclude, Lats1 contributes to the regulation of muscle fiber type proportions, and its expression is regulated by physiological and pathological situations in skeletal muscle.
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19
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Wackerhage H, Vechetti IJ, Baumert P, Gehlert S, Becker L, Jaspers RT, de Angelis MH. Does a Hypertrophying Muscle Fibre Reprogramme its Metabolism Similar to a Cancer Cell? Sports Med 2022; 52:2569-2578. [PMID: 35460513 PMCID: PMC9584876 DOI: 10.1007/s40279-022-01676-1] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/17/2022] [Indexed: 02/01/2023]
Abstract
In 1924, Otto Warburg asked "How does the metabolism of a growing tissue differ from that of a non-growing tissue?" Currently, we know that proliferating healthy and cancer cells reprogramme their metabolism. This typically includes increased glucose uptake, glycolytic flux and lactate synthesis. A key function of this reprogramming is to channel glycolytic intermediates and other metabolites into anabolic reactions such as nucleotide-RNA/DNA synthesis, amino acid-protein synthesis and the synthesis of, for example, acetyl and methyl groups for epigenetic modification. In this review, we discuss evidence that a hypertrophying muscle similarly takes up more glucose and reprogrammes its metabolism to channel energy metabolites into anabolic pathways. We specifically discuss the functions of the cancer-associated enzymes phosphoglycerate dehydrogenase and pyruvate kinase muscle 2 in skeletal muscle. In addition, we ask whether increased glucose uptake by a hypertrophying muscle explains why muscularity is often negatively associated with type 2 diabetes mellitus and obesity.
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Affiliation(s)
- Henning Wackerhage
- Exercise Biology Group, Department of Health and Sports Sciences, Technical University of Munich, Munich, Germany
| | - Ivan J. Vechetti
- Department of Nutrition and Health Sciences, College of Education and Human Sciences, University of Nebraska-Lincoln, Lincoln, NE USA
| | - Philipp Baumert
- Exercise Biology Group, Department of Health and Sports Sciences, Technical University of Munich, Munich, Germany
| | - Sebastian Gehlert
- Department of Biosciences of Sports, Institute for Sports Science, University of Hildesheim, Hildesheim, Germany
| | - Lore Becker
- Institute of Experimental Genetics, Helmholtz Zentrum München, German Research Center for Environmental Health, Munich, Germany
| | - Richard T. Jaspers
- Laboratory for Myology, Behavioural and Movement Sciences, Amsterdam Movement Sciences, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
| | - Martin Hrabě de Angelis
- Institute of Experimental Genetics, Helmholtz Zentrum München, German Research Center for Environmental Health, Munich, Germany ,German Center for Diabetes Research (DZD), Neuherberg, Germany ,Chair of Experimental Genetics, TUM School of Life Sciences, Technische Universität München, Freising, Germany
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20
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Valentino T, Figueiredo VC, Mobley CB, McCarthy JJ, Vechetti IJ. Evidence of myomiR regulation of the pentose phosphate pathway during mechanical load-induced hypertrophy. Physiol Rep 2021; 9:e15137. [PMID: 34889054 PMCID: PMC8661100 DOI: 10.14814/phy2.15137] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2021] [Revised: 10/13/2021] [Accepted: 11/10/2021] [Indexed: 12/29/2022] Open
Abstract
Many of the molecular and cellular mechanisms discovered to regulate skeletal muscle hypertrophy were first identified using the rodent synergist ablation model. This model reveals the intrinsic capability and necessary pathways of skeletal muscle growth in response to mechanical overload (MOV). Reminiscent of the rapid cellular growth observed with cancer, we hypothesized that in response to MOV, skeletal muscle would undergo metabolic programming to sustain increased demands to support hypertrophy. To test this hypothesis, we analyzed the gene expression of specific metabolic pathways taken from transcriptomic microarray data of a MOV time course. We found an upregulation of genes involved in the oxidative branch of the pentose phosphate pathways (PPP) and mitochondrial branch of the folate cycle suggesting an increase in the production of NADPH. In addition, we sought to determine the potential role of skeletal muscle-enriched microRNA (myomiRs) and satellite cells in the regulation of the metabolic pathways that changed during MOV. We observed an inverse pattern in gene expression between muscle-enriched myomiR-1 and its known target gene glucose-6-phosphate dehydrogenase, G6pdx, suggesting myomiR regulation of PPP activation in response to MOV. Satellite cell fusion had a significant but modest impact on PPP gene expression. These transcriptomic findings suggest the robust muscle hypertrophy induced by MOV requires enhanced redox metabolism via PPP production of NADPH which is potentially regulated by a myomiR network.
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Affiliation(s)
- Taylor Valentino
- Department of PhysiologyCollege of MedicineLexingtonKentuckyUSA
- Center for Muscle BiologyUniversity of KentuckyLexingtonKentuckyUSA
| | - Vandre C. Figueiredo
- Center for Muscle BiologyUniversity of KentuckyLexingtonKentuckyUSA
- Department of Physical TherapyCollege of Health SciencesUniversity of KentuckyLexingtonKentuckyUSA
| | | | - John J. McCarthy
- Department of PhysiologyCollege of MedicineLexingtonKentuckyUSA
- Center for Muscle BiologyUniversity of KentuckyLexingtonKentuckyUSA
| | - Ivan J. Vechetti
- Department of Nutrition and Health SciencesCollege of Education and Human SciencesUniversity of Nebraska‐LincolnLincolnNebraskaUSA
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21
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Increasing the resting time between drop jumps lessens delayed-onset muscle soreness and limits the extent of prolonged low-frequency force depression in human knee extensor muscles. Eur J Appl Physiol 2021; 122:255-266. [PMID: 34674024 DOI: 10.1007/s00421-021-04834-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2021] [Accepted: 10/14/2021] [Indexed: 10/20/2022]
Abstract
PURPOSE Unaccustomed eccentric contractions generally result in a long-lasting contractile impairment, referred to as prolonged low-frequency force depression (PLFFD), and delayed-onset muscle soreness (DOMS). We here used repeated drop jumps (DJs) as an eccentric contraction model and studied the effects of increasing the time between DJs from 20 s to 5 min. We hypothesized that both PLFFD and DOMS would be less marked at the longer DJ interval due to the longer time to restore structural elements between DJs. METHODS Young men (n = 12) randomly performed 50 DJs with either 20-s (DJ-20 s) or 5-min (DJ-5 min) rest between DJs. Voluntary, 20 Hz and 100 Hz electrically stimulated isometric knee extension torques and muscle soreness were monitored before and for 7 days after DJs; serum CK activity was measured to assess muscle fibre protein leakage. In additional experiments, changes in mRNA levels were assessed in muscle biopsies collected before and 1 h after exercise. RESULTS A marked PLFFD was observed with both protocols and the extent of 20 Hz torque depression was smaller immediately and 1 day after DJ-5 min than after DJ-20 s (p < 0.05), whereas the MVC and 100 Hz torques were similarly decreased with the two protocols. Markedly larger differences between the two protocols were observed for the muscle soreness score, which 1-4 days after exercise was about two times larger with DJ-20 s than with DJ-5 min (p < 0.01). CONCLUSIONS The larger protective effect of the longer DJ interval against DOMS than against PLFFD indicates that their underlying mechanisms involve different structural elements.
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22
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Mann G, Mora S, Madu G, Adegoke OAJ. Branched-chain Amino Acids: Catabolism in Skeletal Muscle and Implications for Muscle and Whole-body Metabolism. Front Physiol 2021; 12:702826. [PMID: 34354601 PMCID: PMC8329528 DOI: 10.3389/fphys.2021.702826] [Citation(s) in RCA: 62] [Impact Index Per Article: 20.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2021] [Accepted: 06/24/2021] [Indexed: 12/20/2022] Open
Abstract
Branched-chain amino acids (BCAAs) are critical for skeletal muscle and whole-body anabolism and energy homeostasis. They also serve as signaling molecules, for example, being able to activate mammalian/mechanistic target of rapamycin complex 1 (mTORC1). This has implication for macronutrient metabolism. However, elevated circulating levels of BCAAs and of their ketoacids as well as impaired catabolism of these amino acids (AAs) are implicated in the development of insulin resistance and its sequelae, including type 2 diabetes, cardiovascular disease, and of some cancers, although other studies indicate supplements of these AAs may help in the management of some chronic diseases. Here, we first reviewed the catabolism of these AAs especially in skeletal muscle as this tissue contributes the most to whole body disposal of the BCAA. We then reviewed emerging mechanisms of control of enzymes involved in regulating BCAA catabolism. Such mechanisms include regulation of their abundance by microRNA and by post translational modifications such as phosphorylation, acetylation, and ubiquitination. We also reviewed implications of impaired metabolism of BCAA for muscle and whole-body metabolism. We comment on outstanding questions in the regulation of catabolism of these AAs, including regulation of the abundance and post-transcriptional/post-translational modification of enzymes that regulate BCAA catabolism, as well the impact of circadian rhythm, age and mTORC1 on these enzymes. Answers to such questions may facilitate emergence of treatment/management options that can help patients suffering from chronic diseases linked to impaired metabolism of the BCAAs.
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Affiliation(s)
| | | | | | - Olasunkanmi A. J. Adegoke
- Muscle Health Research Centre, School of Kinesiology and Health Science, York University, Toronto, ON, Canada
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23
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Vann CG, Morton RW, Mobley CB, Vechetti IJ, Ferguson BK, Haun CT, Osburn SC, Sexton CL, Fox CD, Romero MA, Roberson PA, Oikawa SY, McGlory C, Young KC, McCarthy JJ, Phillips SM, Roberts MD. An intron variant of the GLI family zinc finger 3 (GLI3) gene differentiates resistance training-induced muscle fiber hypertrophy in younger men. FASEB J 2021; 35:e21587. [PMID: 33891350 PMCID: PMC8234740 DOI: 10.1096/fj.202100113rr] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2021] [Revised: 03/17/2021] [Accepted: 03/25/2021] [Indexed: 12/25/2022]
Abstract
We examined the association between genotype and resistance training-induced changes (12 wk) in dual x-ray energy absorptiometry (DXA)-derived lean soft tissue mass (LSTM) as well as muscle fiber cross-sectional area (fCSA; vastus lateralis; n = 109; age = 22 ± 2 y, BMI = 24.7 ± 3.1 kg/m2 ). Over 315 000 genetic polymorphisms were interrogated from muscle using DNA microarrays. First, a targeted investigation was performed where single nucleotide polymorphisms (SNP) identified from a systematic literature review were related to changes in LSTM and fCSA. Next, genome-wide association (GWA) studies were performed to reveal associations between novel SNP targets with pre- to post-training change scores in mean fCSA and LSTM. Our targeted investigation revealed no genotype-by-time interactions for 12 common polymorphisms regarding the change in mean fCSA or change in LSTM. Our first GWA study indicated no SNP were associated with the change in LSTM. However, the second GWA study indicated two SNP exceeded the significance level with the change in mean fCSA (P = 6.9 × 10-7 for rs4675569, 1.7 × 10-6 for rs10263647). While the former target is not annotated (chr2:205936846 (GRCh38.p12)), the latter target (chr7:41971865 (GRCh38.p12)) is an intron variant of the GLI Family Zinc Finger 3 (GLI3) gene. Follow-up analyses indicated fCSA increases were greater in the T/C and C/C GLI3 genotypes than the T/T GLI3 genotype (P < .05). Data from the Auburn cohort also revealed participants with the T/C and C/C genotypes exhibited increases in satellite cell number with training (P < .05), whereas T/T participants did not. Additionally, those with the T/C and C/C genotypes achieved myonuclear addition in response to training (P < .05), whereas the T/T participants did not. In summary, this is the first GWA study to examine how polymorphisms associate with the change in hypertrophy measures following resistance training. Future studies are needed to determine if the GLI3 variant differentiates hypertrophic responses to resistance training given the potential link between this gene and satellite cell physiology.
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Affiliation(s)
- Christopher G Vann
- School of Kinesiology, Auburn University, Auburn, AL, USA.,Duke Molecular Physiology Institute, Duke University School of Medicine, Duke University, Durham, NC, USA
| | - Robert W Morton
- Department of Kinesiology, McMaster University, Hamilton, Ontario, Canada
| | - Christopher B Mobley
- Department of Physiology, College of Medicine, University of Kentucky, Lexington, KY, USA.,The Center for Muscle Biology, University of Kentucky, Lexington, KY, USA
| | - Ivan J Vechetti
- Department of Nutrition and Health Sciences, University of Nebraska-Lincoln, Lincoln, NE, USA
| | | | | | | | - Casey L Sexton
- School of Kinesiology, Auburn University, Auburn, AL, USA
| | - Carlton D Fox
- School of Kinesiology, Auburn University, Auburn, AL, USA
| | | | | | - Sara Y Oikawa
- Department of Kinesiology, McMaster University, Hamilton, Ontario, Canada
| | - Chris McGlory
- Department of Kinesiology, McMaster University, Hamilton, Ontario, Canada
| | - Kaelin C Young
- School of Kinesiology, Auburn University, Auburn, AL, USA.,Department of Cell Biology and Physiology, Edward Via College of Osteopathic Medicine, Auburn, AL, USA
| | - John J McCarthy
- Department of Physiology, College of Medicine, University of Kentucky, Lexington, KY, USA.,The Center for Muscle Biology, University of Kentucky, Lexington, KY, USA
| | - Stuart M Phillips
- Department of Kinesiology, McMaster University, Hamilton, Ontario, Canada
| | - Michael D Roberts
- School of Kinesiology, Auburn University, Auburn, AL, USA.,Department of Cell Biology and Physiology, Edward Via College of Osteopathic Medicine, Auburn, AL, USA
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24
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Deane CS, Willis CRG, Phillips BE, Atherton PJ, Harries LW, Ames RM, Szewczyk NJ, Etheridge T. Transcriptomic meta-analysis of disuse muscle atrophy vs. resistance exercise-induced hypertrophy in young and older humans. J Cachexia Sarcopenia Muscle 2021; 12:629-645. [PMID: 33951310 PMCID: PMC8200445 DOI: 10.1002/jcsm.12706] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/14/2020] [Revised: 02/26/2021] [Accepted: 03/29/2021] [Indexed: 12/14/2022] Open
Abstract
BACKGROUND Skeletal muscle atrophy manifests across numerous diseases; however, the extent of similarities/differences in causal mechanisms between atrophying conditions in unclear. Ageing and disuse represent two of the most prevalent and costly atrophic conditions, with resistance exercise training (RET) being the most effective lifestyle countermeasure. We employed gene-level and network-level meta-analyses to contrast transcriptomic signatures of disuse and RET, plus young and older RET to establish a consensus on the molecular features of, and therapeutic targets against, muscle atrophy in conditions of high socio-economic relevance. METHODS Integrated gene-level and network-level meta-analysis was performed on publicly available microarray data sets generated from young (18-35 years) m. vastus lateralis muscle subjected to disuse (unilateral limb immobilization or bed rest) lasting ≥7 days or RET lasting ≥3 weeks, and resistance-trained older (≥60 years) muscle. RESULTS Disuse and RET displayed predominantly separate transcriptional responses, and transcripts altered across conditions were mostly unidirectional. However, disuse and RET induced directly inverted expression profiles for mitochondrial function and translation regulation genes, with COX4I1, ENDOG, GOT2, MRPL12, and NDUFV2, the central hub components of altered mitochondrial networks, and ZMYND11, a hub gene of altered translation regulation. A substantial number of genes (n = 140) up-regulated post-RET in younger muscle were not similarly up-regulated in older muscle, with young muscle displaying a more pronounced extracellular matrix (ECM) and immune/inflammatory gene expression response. Both young and older muscle exhibited similar RET-induced ubiquitination/RNA processing gene signatures with associated PWP1, PSMB1, and RAF1 hub genes. CONCLUSIONS Despite limited opposing gene profiles, transcriptional signatures of disuse are not simply the converse of RET. Thus, the mechanisms of unloading cannot be derived from studying muscle loading alone and provides a molecular basis for understanding why RET fails to target all transcriptional features of disuse. Loss of RET-induced ECM mechanotransduction and inflammatory profiles might also contribute to suboptimal ageing muscle adaptations to RET. Disuse and age-dependent molecular candidates further establish a framework for understanding and treating disuse/ageing atrophy.
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Affiliation(s)
- Colleen S Deane
- Department of Sport and Health Sciences, College of Life and Environmental Sciences, University of Exeter, St. Luke's Campus, Exeter, UK.,Living Systems Institute, University of Exeter, Exeter, UK
| | - Craig R G Willis
- Department of Sport and Health Sciences, College of Life and Environmental Sciences, University of Exeter, St. Luke's Campus, Exeter, UK
| | - Bethan E Phillips
- MRC-ARUK Centre for Musculoskeletal Ageing Research and National Institute of Health Research, Biomedical Research Centre, Division of Medical Sciences and Graduate Entry Medicine, Royal Derby Hospital Centre, School of Medicine, University of Nottingham, Derby, UK
| | - Philip J Atherton
- MRC-ARUK Centre for Musculoskeletal Ageing Research and National Institute of Health Research, Biomedical Research Centre, Division of Medical Sciences and Graduate Entry Medicine, Royal Derby Hospital Centre, School of Medicine, University of Nottingham, Derby, UK
| | - Lorna W Harries
- RNA-Mediated Mechanisms of Disease Group, Institute of Biomedical and Clinical Sciences, University of Exeter Medical School, University of Exeter, Exeter, UK
| | - Ryan M Ames
- Living Systems Institute, University of Exeter, Exeter, UK
| | - Nathaniel J Szewczyk
- MRC-ARUK Centre for Musculoskeletal Ageing Research and National Institute of Health Research, Biomedical Research Centre, Division of Medical Sciences and Graduate Entry Medicine, Royal Derby Hospital Centre, School of Medicine, University of Nottingham, Derby, UK.,Ohio Musculoskeletal and Neurological Institute & Department of Biomedical Sciences, Ohio University, Athens, OH, USA
| | - Timothy Etheridge
- Department of Sport and Health Sciences, College of Life and Environmental Sciences, University of Exeter, St. Luke's Campus, Exeter, UK
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25
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Goodman CA, Davey JR, Hagg A, Parker BL, Gregorevic P. Dynamic Changes to the Skeletal Muscle Proteome and Ubiquitinome Induced by the E3 Ligase, ASB2β. Mol Cell Proteomics 2021; 20:100050. [PMID: 33516941 PMCID: PMC8042406 DOI: 10.1016/j.mcpro.2021.100050] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2020] [Revised: 01/12/2021] [Accepted: 01/15/2021] [Indexed: 02/06/2023] Open
Abstract
Ubiquitination is a posttranslational protein modification that has been shown to have a range of effects, including regulation of protein function, interaction, localization, and degradation. We have previously shown that the muscle-specific ubiquitin E3 ligase, ASB2β, is downregulated in models of muscle growth and that overexpression ASB2β is sufficient to induce muscle atrophy. To gain insight into the effects of increased ASB2β expression on skeletal muscle mass and function, we used liquid chromatography coupled to tandem mass spectrometry to investigate ASB2β-mediated changes to the skeletal muscle proteome and ubiquitinome, via a parallel analysis of remnant diGly-modified peptides. The results show that viral vector-mediated ASB2β overexpression in murine muscles causes progressive muscle atrophy and impairment of force-producing capacity, while ASB2β knockdown induces mild muscle hypertrophy. ASB2β-induced muscle atrophy and dysfunction were associated with the early downregulation of mitochondrial and contractile protein abundance and the upregulation of proteins involved in proteasome-mediated protein degradation (including other E3 ligases), protein synthesis, and the cytoskeleton/sarcomere. The overexpression ASB2β also resulted in marked changes in protein ubiquitination; however, there was no simple relationship between changes in ubiquitination status and protein abundance. To investigate proteins that interact with ASB2β and, therefore, potential ASB2β targets, Flag-tagged wild-type ASB2β, and a mutant ASB2β lacking the C-terminal SOCS box domain (dSOCS) were immunoprecipitated from C2C12 myotubes and subjected to label-free proteomic analysis to determine the ASB2β interactome. ASB2β was found to interact with a range of cytoskeletal and nuclear proteins. When combined with the in vivo ubiquitinomic data, our studies have identified novel putative ASB2β target substrates that warrant further investigation. These findings provide novel insight into the complexity of proteome and ubiquitinome changes that occur during E3 ligase-mediated skeletal muscle atrophy and dysfunction.
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Affiliation(s)
- Craig A Goodman
- Department of Physiology, Centre for Muscle Research (CMR), The University of Melbourne, Victoria, Australia; Australian Institute for Musculoskeletal Science (AIMSS), Sunshine Hospital, The University of Melbourne, St Albans, Victoria, Australia
| | - Jonathan R Davey
- Department of Physiology, Centre for Muscle Research (CMR), The University of Melbourne, Victoria, Australia; Baker Heart and Diabetes Institute, Melbourne, Victoria, Australia
| | - Adam Hagg
- Department of Physiology, Centre for Muscle Research (CMR), The University of Melbourne, Victoria, Australia; Baker Heart and Diabetes Institute, Melbourne, Victoria, Australia; Department of Physiology, Monash Biomedicine Discovery Institute, Monash University, Clayton, Victoria, Australia
| | - Benjamin L Parker
- Department of Physiology, Centre for Muscle Research (CMR), The University of Melbourne, Victoria, Australia; Charles Perkins Centre, School of Life and Environmental Science, The University of Sydney, Sydney, NSW, Australia.
| | - Paul Gregorevic
- Department of Physiology, Centre for Muscle Research (CMR), The University of Melbourne, Victoria, Australia; Baker Heart and Diabetes Institute, Melbourne, Victoria, Australia; Department of Biochemistry and Molecular Biology, Monash University, Clayton, Victoria, Australia; Department of Neurology, The University of Washington School of Medicine, Seattle, Washington, USA.
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26
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West DWD, Doering TM, Thompson JLM, Budiono BP, Lessard SJ, Koch LG, Britton SL, Steck R, Byrne NM, Brown MA, Peake JM, Ashton KJ, Coffey VG. Low responders to endurance training exhibit impaired hypertrophy and divergent biological process responses in rat skeletal muscle. Exp Physiol 2021; 106:714-725. [PMID: 33486778 DOI: 10.1113/ep089301] [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: 11/26/2020] [Accepted: 01/19/2021] [Indexed: 12/11/2022]
Abstract
NEW FINDINGS What is the central question of this study? The extent to which genetics determines adaptation to endurance versus resistance exercise is unclear. Previously, a divergent selective breeding rat model showed that genetic factors play a major role in the response to aerobic training. Here, we asked: do genetic factors that underpin poor adaptation to endurance training affect adaptation to functional overload? What is the main finding and its importance? Our data show that heritable factors in low responders to endurance training generated differential gene expression that was associated with impaired skeletal muscle hypertrophy. A maladaptive genotype to endurance exercise appears to dysregulate biological processes responsible for mediating exercise adaptation, irrespective of the mode of contraction stimulus. ABSTRACT Divergent skeletal muscle phenotypes result from chronic resistance-type versus endurance-type contraction, reflecting the principle of training specificity. Our aim was to determine whether there is a common set of genetic factors that influence skeletal muscle adaptation to divergent contractile stimuli. Female rats were obtained from a genetically heterogeneous rat population and were selectively bred from high responders to endurance training (HRT) or low responders to endurance training (LRT; n = 6/group; generation 19). Both groups underwent 14 days of synergist ablation to induce functional overload of the plantaris muscle before comparison to non-overloaded controls of the same phenotype. RNA sequencing was performed to identify Gene Ontology biological processes with differential (LRT vs. HRT) gene set enrichment. We found that running distance, determined in advance of synergist ablation, increased in response to aerobic training in HRT but not LRT (65 ± 26 vs. -6 ± 18%, mean ± SD, P < 0.0001). The hypertrophy response to functional overload was attenuated in LRT versus HRT (20.1 ± 5.6 vs. 41.6 ± 16.1%, P = 0.015). Between-group differences were observed in the magnitude of response of 96 upregulated and 101 downregulated pathways. A further 27 pathways showed contrasting upregulation or downregulation in LRT versus HRT in response to functional overload. In conclusion, low responders to aerobic endurance training were also low responders for compensatory hypertrophy, and attenuated hypertrophy was associated with differential gene set regulation. Our findings suggest that genetic factors that underpin aerobic training maladaptation might also dysregulate the transcriptional regulation of biological processes that contribute to adaptation to mechanical overload.
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Affiliation(s)
- Daniel W D West
- Department of Physiology and Membrane Biology, University of California Davis, Davis, California, USA.,Toronto Rehabilitation Institute, Toronto, Ontario, Canada.,Faculty of Kinesiology and Physical Education, University of Toronto, Toronto, Ontario, Canada
| | - Thomas M Doering
- Faculty of Health Sciences and Medicine, Bond University, Robina, Gold Coast, Queensland, Australia.,School of Health, Medical and Applied Sciences, Central Queensland University, Rockhampton, Queensland, Australia
| | - Jamie-Lee M Thompson
- Faculty of Health Sciences and Medicine, Bond University, Robina, Gold Coast, Queensland, Australia
| | - Boris P Budiono
- School of Community Health, Charles Sturt University, Port Macquarie, New South Wales, Australia
| | - Sarah J Lessard
- Research Division, Joslin Diabetes Center, Boston, Massachusetts, USA.,Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts, USA
| | - Lauren G Koch
- Department of Physiology and Pharmacology, University of Toledo, Toledo, Ohio, USA
| | - Steven L Britton
- Department of Anesthesiology, University of Michigan, Ann Arbor, Michigan, USA
| | - Roland Steck
- Institute of Health and Biomedical Innovation, Queensland University of Technology, Brisbane, Queensland, Australia
| | - Nuala M Byrne
- School of Health Sciences, University of Tasmania, Launceston, Tasmania, Australia
| | - Matthew A Brown
- Guy's & St Thomas' NHS Foundation Trust and King's College London NIHR Biomedical Research Centre, London, UK
| | - Jonathan M Peake
- Institute of Health and Biomedical Innovation, Queensland University of Technology, Brisbane, Queensland, Australia
| | - Kevin J Ashton
- Faculty of Health Sciences and Medicine, Bond University, Robina, Gold Coast, Queensland, Australia
| | - Vernon G Coffey
- Faculty of Health Sciences and Medicine, Bond University, Robina, Gold Coast, Queensland, Australia
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27
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Murach KA, Mobley CB, Zdunek CJ, Frick KK, Jones SR, McCarthy JJ, Peterson CA, Dungan CM. Muscle memory: myonuclear accretion, maintenance, morphology, and miRNA levels with training and detraining in adult mice. J Cachexia Sarcopenia Muscle 2020; 11:1705-1722. [PMID: 32881361 PMCID: PMC7749570 DOI: 10.1002/jcsm.12617] [Citation(s) in RCA: 39] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/26/2020] [Revised: 08/06/2020] [Accepted: 08/10/2020] [Indexed: 12/18/2022] Open
Abstract
BACKGROUND In the context of mass regulation, 'muscle memory' can be defined as long-lasting cellular adaptations to hypertrophic exercise training that persist during detraining-induced atrophy and may facilitate future adaptation. The cellular basis of muscle memory is not clearly defined but may be related to myonuclear number and/or epigenetic changes within muscle fibres. METHODS Utilizing progressive weighted wheel running (PoWeR), a novel murine exercise training model, we explored myonuclear dynamics and skeletal muscle miRNA levels with training and detraining utilizing immunohistochemistry, single fibre myonuclear analysis, and quantitative analysis of miRNAs. We also used a genetically inducible mouse model of fluorescent myonuclear labelling to study myonuclear adaptations early during exercise. RESULTS In the soleus, oxidative type 2a fibres were larger after 2 months of PoWeR (P = 0.02), but muscle fibre size and myonuclear number did not return to untrained levels after 6 months of detraining. Soleus type 1 fibres were not larger after PoWeR but had significantly more myonuclei, as well as central nuclei (P < 0.0001), the latter from satellite cell-derived or resident myonuclei, appearing early during training and remaining with detraining. In the gastrocnemius muscle, oxidative type 2a fibres of the deep region were larger and contained more myonuclei after PoWeR (P < 0.003), both of which returned to untrained levels after detraining. In the gastrocnemius and plantaris, two muscles where myonuclear number was comparable with untrained levels after 6 months of detraining, myonuclei were significantly elongated with detraining (P < 0.0001). In the gastrocnemius, miR-1 was lower with training and remained lower after detraining (P < 0.002). CONCLUSIONS This study found that (i) myonuclei gained during hypertrophy are lost with detraining across muscles, even in oxidative fibres; (ii) complete reversal of muscle adaptations, including myonuclear number, to untrained levels occurs within 6 months in the plantaris and gastrocnemius; (iii) the murine soleus is resistant to detraining; (iv) myonuclear accretion occurs early with wheel running and can be uncoupled from muscle fibre hypertrophy; (v) resident (non-satellite cell-derived) myonuclei can adopt a central location; (vi) myonuclei change shape with training and detraining; and (vii) miR-1 levels may reflect a memory of previous adaptation that facilitates future growth.
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Affiliation(s)
- Kevin A. Murach
- Department of Physical TherapyUniversity of KentuckyLexingtonKYUSA
- Center for Muscle BiologyUniversity of KentuckyLexingtonKYUSA
| | - C. Brooks Mobley
- Department of PhysiologyUniversity of KentuckyLexingtonKYUSA
- Center for Muscle BiologyUniversity of KentuckyLexingtonKYUSA
| | | | | | | | - John J. McCarthy
- Department of PhysiologyUniversity of KentuckyLexingtonKYUSA
- Center for Muscle BiologyUniversity of KentuckyLexingtonKYUSA
| | - Charlotte A. Peterson
- Department of Physical TherapyUniversity of KentuckyLexingtonKYUSA
- Center for Muscle BiologyUniversity of KentuckyLexingtonKYUSA
| | - Cory M. Dungan
- Department of Physical TherapyUniversity of KentuckyLexingtonKYUSA
- Center for Muscle BiologyUniversity of KentuckyLexingtonKYUSA
- Sanders‐Brown Center on AgingUniversity of KentuckyLexingtonKYUSA
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28
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Smith LR, Kok HJ, Zhang B, Chung D, Spradlin RA, Rakoczy KD, Lei H, Boesze-Battaglia K, Barton ER. Matrix Metalloproteinase 13 from Satellite Cells is Required for Efficient Muscle Growth and Regeneration. Cell Physiol Biochem 2020; 54:333-353. [PMID: 32275813 DOI: 10.33594/000000223] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/25/2020] [Indexed: 12/12/2022] Open
Abstract
BACKGROUND/AIMS Cell migration and extracellular matrix remodeling underlie normal mammalian development and growth as well as pathologic tumor invasion. Skeletal muscle is no exception, where satellite cell migration replenishes nuclear content in damaged tissue and extracellular matrix reforms during regeneration. A key set of enzymes that regulate these processes are matrix metalloproteinases (MMP)s. The collagenase MMP-13 is transiently upregulated during muscle regeneration, but its contribution to damage resolution is unknown. The purpose of this work was to examine the importance of MMP-13 in muscle regeneration and growth in vivo and to delineate a satellite cell specific role for this collagenase. METHODS Mice with total and satellite cell specific Mmp13 deletion were utilized to determine the importance of MMP-13 for postnatal growth, regeneration after acute injury, and in chronic injury from a genetic cross with dystrophic (mdx) mice. We also evaluated insulin-like growth factor 1 (IGF-1) mediated hypertrophy in the presence and absence of MMP-13. We employed live-cell imaging and 3D migration measurements on primary myoblasts obtained from these animals. Outcome measures included muscle morphology and function. RESULTS Under basal conditions, Mmp13-/- mice did not exhibit histological or functional deficits in muscle. However, following acute injury, regeneration was impaired at 11 and 14 days post injury. Muscle hypertrophy caused by increased IGF-1 was blunted with minimal satellite cell incorporation in the absence of MMP-13. Mmp13-/- primary myoblasts displayed reduced migratory capacity in 2D and 3D, while maintaining normal proliferation and differentiation. Satellite cell specific deletion of MMP-13 recapitulated the effects of global MMP-13 ablation on muscle regeneration, growth and myoblast movement. CONCLUSION These results show that satellite cells provide an essential autocrine source of MMP-13, which not only regulates their migration, but also supports postnatal growth and resolution of acute damage.
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Affiliation(s)
- Lucas R Smith
- Anatomy and Cell Biology, School of Dental Medicine, University of Pennsylvania, Philadelphia, PA, USA.,Neurobiology, Physiology & Behavior, Physical Medicine & Rehabilitation, University of California, Davis, CA, USA
| | - Hui Jean Kok
- Applied Physiology and Kinesiology, College of Health and Human Performance, University of Florida, Gainesville, FL, USA
| | - Boshi Zhang
- Anatomy and Cell Biology, School of Dental Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Du Chung
- Anatomy and Cell Biology, School of Dental Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Ray A Spradlin
- Applied Physiology and Kinesiology, College of Health and Human Performance, University of Florida, Gainesville, FL, USA
| | - Kyla D Rakoczy
- Applied Physiology and Kinesiology, College of Health and Human Performance, University of Florida, Gainesville, FL, USA
| | - Hanqin Lei
- Anatomy and Cell Biology, School of Dental Medicine, University of Pennsylvania, Philadelphia, PA, USA.,Applied Physiology and Kinesiology, College of Health and Human Performance, University of Florida, Gainesville, FL, USA
| | | | - Elisabeth R Barton
- Anatomy and Cell Biology, School of Dental Medicine, University of Pennsylvania, Philadelphia, PA, USA, .,Applied Physiology and Kinesiology, College of Health and Human Performance, University of Florida, Gainesville, FL, USA
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29
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Von Walden F, Rea M, Mobley CB, Fondufe-Mittendorf Y, McCarthy JJ, Peterson CA, Murach KA. The myonuclear DNA methylome in response to an acute hypertrophic stimulus. Epigenetics 2020; 15:1151-1162. [PMID: 32281477 PMCID: PMC7595631 DOI: 10.1080/15592294.2020.1755581] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
In addition to multi-nucleated muscle fibres, numerous resident and infiltrating mononuclear cells populate the muscle compartment. As most epigenetic assays in skeletal muscle are conducted on whole tissue homogenates, essentially nothing is known about regulatory processes exclusively within muscle fibres in vivo. Utilizing a novel genetically modified mouse model developed by our laboratory, we (1) outline a simple and rapid workflow for isolating pure myonuclei from small tissue samples via fluorescent activated cell sorting and extracting high-quality large-fragment DNA for downstream analyses, and (2) provide information on myonuclear and interstitial cell nuclear CpG DNA methylation via reduced representation bisulphite sequencing (RRBS) using mice that were subjected to an acute mechanical overload of the plantaris muscle. In 3-month-old mice, myonuclei are ~50% of total nuclei in sham and ~30% in 3-d overloaded muscle, the difference being attributable to mononuclear cell infiltration and proliferation with overload. In purified myonuclei, pathway analysis of hypomethylated promoter regions following overload was distinct from interstitial nuclei and revealed marked regulation of factors that converge on the master regulator of muscle growth mTOR, and on autophagy. Specifically, acute hypomethylation of Rheb, Rictor, Hdac1, and Hdac2, in addition to a major driver of ribosome biogenesis Myc, reveals the epigenetic regulation of hypertrophic signalling within muscle fibres that may underpin the long-term growth response to loading. This study provides foundational information on global myonuclear epigenetics in vivo using RRBS, and demonstrates the importance of isolating specific nuclear populations to study the epigenetic regulation of skeletal muscle fibre adaptation.
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Affiliation(s)
- Ferdinand Von Walden
- K6 Department of Women’s and Children’s Health, Karolinska Institute, Stockholm, Sweden
- Department of Physiology, University of Kentucky, Lexington, KY, USA
- The Center for Muscle Biology, University of Kentucky, Lexington, KY, USA
| | - Matthew Rea
- Department of Molecular and Cellular Biochemistry, University of Kentucky, Lexington, KY, USA
| | - C. Brooks Mobley
- Department of Physiology, University of Kentucky, Lexington, KY, USA
- The Center for Muscle Biology, University of Kentucky, Lexington, KY, USA
| | | | - John J. McCarthy
- Department of Physiology, University of Kentucky, Lexington, KY, USA
- The Center for Muscle Biology, University of Kentucky, Lexington, KY, USA
| | - Charlotte A. Peterson
- Department of Physiology, University of Kentucky, Lexington, KY, USA
- The Center for Muscle Biology, University of Kentucky, Lexington, KY, USA
- Department of Physical Therapy, University of Kentucky, Lexington, KY, USA
| | - Kevin A. Murach
- The Center for Muscle Biology, University of Kentucky, Lexington, KY, USA
- Department of Physical Therapy, University of Kentucky, Lexington, KY, USA
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30
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Zhang L, Chen Q, Chen Z, Wang Y, Gamboa JL, Ikizler TA, Garibotto G, Mitch WE. Mechanisms Regulating Muscle Protein Synthesis in CKD. J Am Soc Nephrol 2020; 31:2573-2587. [PMID: 32764136 DOI: 10.1681/asn.2019121277] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2019] [Accepted: 06/21/2020] [Indexed: 12/20/2022] Open
Abstract
BACKGROUND CKD induces loss of muscle proteins partly by suppressing muscle protein synthesis. Muscles of mice with CKD have increased expression of nucleolar protein 66 (NO66), as do muscle biopsy specimens from patients with CKD or those undergoing hemodialysis. Inflammation stimulates NO66 expression and changes in NF-κB mediate the response. METHODS Subtotal nephrectomy created a mouse model of CKD with BUN >80 mg/dl. Crossing NO66flox/flox with MCK-Cre mice bred muscle-specific NO66 (MCK-NO66) knockout mice. Experiments assessed the effect of removing NO66. RESULTS Muscle-specific NO66 knockout in mice blocks CKD-induced loss of muscle mass and improves protein synthesis. NO66 suppression of ribosomal biogenesis via demethylase activity is the mechanism behind these responses. In muscle cells, expression of NO66, but not of demethylase-dead mutant NO66, decreased H3K4me3 and H3K36me3 and suppressed pre-rRNA expression. Knocking out NO66 increased the enrichment of H3K4me3 and H3K36me3 on ribosomal DNA. In primary muscle cells and in muscles of mice without NO66, ribosomal RNA, pre-rRNA, and protein synthesis all increased. CONCLUSIONS CKD suppresses muscle protein synthesis via epigenetic mechanisms that NO66 mediates. Blocking NO66 could suggest strategies that counter CKD-induced abnormal muscle protein catabolism.
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Affiliation(s)
- Liping Zhang
- Nephrology Division, Department of Medicine, Baylor College of Medicine, Houston, Texas
| | - Qin Chen
- Department of Epigenetics and Molecular Carcinogenesis, The University of Texas MD Anderson Cancer Center, Houston, Texas
| | - Zihong Chen
- Nephrology Division, Department of Medicine, Baylor College of Medicine, Houston, Texas
| | - Ying Wang
- Nephrology Division, Department of Medicine, Baylor College of Medicine, Houston, Texas
| | - Jorge L Gamboa
- Department of Medicine, Vanderbilt University Medical Center, Nashville, Tennessee
| | - Talat Alp Ikizler
- Department of Medicine, Vanderbilt University Medical Center, Nashville, Tennessee
| | - Giacomo Garibotto
- Nephrology Division, Department of Internal Medicine, Genoa University, Scientific Hospitalization and Treatment Institute Policlinico San Martino Hospital, Genoa, Italy
| | - William E Mitch
- Nephrology Division, Department of Medicine, Baylor College of Medicine, Houston, Texas
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31
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Murach KA, McCarthy JJ, Peterson CA, Dungan CM. Making Mice Mighty: recent advances in translational models of load-induced muscle hypertrophy. J Appl Physiol (1985) 2020; 129:516-521. [PMID: 32673155 DOI: 10.1152/japplphysiol.00319.2020] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
The ability to genetically manipulate mice allows for gain- and loss-of-function in vivo, making them an ideal model for elucidating mechanisms of skeletal muscle mass regulation. Combining genetic models with mechanical muscle loading enables identification of specific factors involved in the hypertrophic response as well as the ability to test the requirement of those factors for adaptation, thereby informing performance and therapeutic interventions. Until recently, approaches for inducing mechanically mediated muscle hypertrophy (i.e., resistance-training analogs) have been limited and considered "nontranslatable" to humans. This mini-review outlines recent translational advances in loading-mediated strategies for inducing muscle hypertrophy in mice, and highlights the advantages and disadvantages of each method. The skeletal muscle field is poised for new breakthroughs in understanding mechanisms regulating load-induced muscle growth given the numerous murine tools that have very recently been described.
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Affiliation(s)
- Kevin A Murach
- The Center for Muscle Biology, University of Kentucky, Lexington, Kentucky.,Department of Physical Therapy, College of Health Sciences, University of Kentucky, Lexington, Kentucky
| | - John J McCarthy
- The Center for Muscle Biology, University of Kentucky, Lexington, Kentucky.,Department of Physiology, College of Medicine, University of Kentucky, Lexington, Kentucky
| | - Charlotte A Peterson
- The Center for Muscle Biology, University of Kentucky, Lexington, Kentucky.,Department of Physical Therapy, College of Health Sciences, University of Kentucky, Lexington, Kentucky.,Department of Physiology, College of Medicine, University of Kentucky, Lexington, Kentucky
| | - Cory M Dungan
- The Center for Muscle Biology, University of Kentucky, Lexington, Kentucky.,Department of Physical Therapy, College of Health Sciences, University of Kentucky, Lexington, Kentucky
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32
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Murach KA, Vechetti IJ, Van Pelt DW, Crow SE, Dungan CM, Figueiredo VC, Kosmac K, Fu X, Richards CI, Fry CS, McCarthy JJ, Peterson CA. Fusion-Independent Satellite Cell Communication to Muscle Fibers During Load-Induced Hypertrophy. FUNCTION 2020; 1:zqaa009. [PMID: 32864621 PMCID: PMC7448100 DOI: 10.1093/function/zqaa009] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2020] [Revised: 06/29/2020] [Accepted: 06/29/2020] [Indexed: 01/06/2023] Open
Abstract
The "canonical" function of Pax7+ muscle stem cells (satellite cells) during hypertrophic growth of adult muscle fibers is myonuclear donation via fusion to support increased transcriptional output. In recent years, however, emerging evidence suggests that satellite cells play an important secretory role in promoting load-mediated growth. Utilizing genetically modified mouse models of delayed satellite cell fusion and in vivo extracellular vesicle (EV) tracking, we provide evidence for satellite cell communication to muscle fibers during hypertrophy. Myogenic progenitor cell-EV-mediated communication to myotubes in vitro influences extracellular matrix (ECM)-related gene expression, which is congruent with in vivo overload experiments involving satellite cell depletion, as well as in silico analyses. Satellite cell-derived EVs can transfer a Cre-induced, cytoplasmic-localized fluorescent reporter to muscle cells as well as microRNAs that regulate ECM genes such as matrix metalloproteinase 9 (Mmp9), which may facilitate growth. Delayed satellite cell fusion did not limit long-term load-induced muscle hypertrophy indicating that early fusion-independent communication from satellite cells to muscle fibers is an underappreciated aspect of satellite cell biology. We cannot exclude the possibility that satellite cell-mediated myonuclear accretion is necessary to maintain prolonged growth, specifically in the later phases of adaptation, but these data collectively highlight how EV delivery from satellite cells can directly contribute to mechanical load-induced muscle fiber hypertrophy, independent of cell fusion to the fiber.
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Affiliation(s)
- Kevin A Murach
- The Center for Muscle Biology, University of Kentucky, Lexington, KY 40536, USA
- Department of Physical Therapy, College of Health Sciences, University of Kentucky, Lexington, KY 40536, USA
| | - Ivan J Vechetti
- The Center for Muscle Biology, University of Kentucky, Lexington, KY 40536, USA
- Department of Physiology, College of Medicine, University of Kentucky, Lexington, KY 40536, USA
| | - Douglas W Van Pelt
- The Center for Muscle Biology, University of Kentucky, Lexington, KY 40536, USA
- Department of Physical Therapy, College of Health Sciences, University of Kentucky, Lexington, KY 40536, USA
| | - Samuel E Crow
- The Center for Muscle Biology, University of Kentucky, Lexington, KY 40536, USA
- Department of Physical Therapy, College of Health Sciences, University of Kentucky, Lexington, KY 40536, USA
| | - Cory M Dungan
- The Center for Muscle Biology, University of Kentucky, Lexington, KY 40536, USA
- Department of Physical Therapy, College of Health Sciences, University of Kentucky, Lexington, KY 40536, USA
| | - Vandre C Figueiredo
- The Center for Muscle Biology, University of Kentucky, Lexington, KY 40536, USA
- Department of Physical Therapy, College of Health Sciences, University of Kentucky, Lexington, KY 40536, USA
| | - Kate Kosmac
- The Center for Muscle Biology, University of Kentucky, Lexington, KY 40536, USA
- Department of Physical Therapy, College of Health Sciences, University of Kentucky, Lexington, KY 40536, USA
| | - Xu Fu
- Department of Chemistry, College of Arts and Sciences, University of Kentucky, Lexington, KY 40536, USA
| | - Christopher I Richards
- Department of Chemistry, College of Arts and Sciences, University of Kentucky, Lexington, KY 40536, USA
| | - Christopher S Fry
- The Center for Muscle Biology, University of Kentucky, Lexington, KY 40536, USA
- Department of Athletic Training and Clinical Nutrition, College of Health Sciences, University of Kentucky, Lexington, KY 40536, USA
| | - John J McCarthy
- The Center for Muscle Biology, University of Kentucky, Lexington, KY 40536, USA
- Department of Physiology, College of Medicine, University of Kentucky, Lexington, KY 40536, USA
| | - Charlotte A Peterson
- The Center for Muscle Biology, University of Kentucky, Lexington, KY 40536, USA
- Department of Physical Therapy, College of Health Sciences, University of Kentucky, Lexington, KY 40536, USA
- Department of Physiology, College of Medicine, University of Kentucky, Lexington, KY 40536, USA
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33
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Insulin Resistance Does Not Impair Mechanical Overload-Stimulated Glucose Uptake, but Does Alter the Metabolic Fate of Glucose in Mouse Muscle. Int J Mol Sci 2020; 21:ijms21134715. [PMID: 32630335 PMCID: PMC7370044 DOI: 10.3390/ijms21134715] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2020] [Revised: 06/28/2020] [Accepted: 06/30/2020] [Indexed: 11/16/2022] Open
Abstract
Skeletal muscle glucose uptake and glucose metabolism are impaired in insulin resistance. Mechanical overload stimulates glucose uptake into insulin-resistant muscle; yet the mechanisms underlying this beneficial effect remain poorly understood. This study examined whether a differential partitioning of glucose metabolism is part of the mechanosensitive mechanism underlying overload-stimulated glucose uptake in insulin-resistant muscle. Mice were fed a high-fat diet to induce insulin resistance. Plantaris muscle overload was induced by unilateral synergist ablation. After 5 days, muscles were excised for the following measurements: (1) [3H]-2-deoxyglucose uptake; (2) glycogen; 3) [5-3H]-glucose flux through glycolysis; (4) lactate secretion; (5) metabolites; and (6) immunoblots. Overload increased glucose uptake ~80% in both insulin-sensitive and insulin-resistant muscles. Overload increased glycogen content ~20% and this was enhanced to ~40% in the insulin-resistant muscle. Overload did not alter glycolytic flux, but did increase muscle lactate secretion 40–50%. In both insulin-sensitive and insulin-resistant muscles, overload increased 6-phosphogluconate levels ~150% and decreased NADP:NADPH ~60%, indicating pentose phosphate pathway activation. Overload increased protein O-GlcNAcylation ~45% and this was enhanced to ~55% in the insulin-resistant muscle, indicating hexosamine pathway activation. In conclusion, insulin resistance does not impair mechanical overload-stimulated glucose uptake but does alter the metabolic fate of glucose in muscle.
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34
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Regulation of Skeletal Muscle Glucose Transport and Glucose Metabolism by Exercise Training. Nutrients 2019; 11:nu11102432. [PMID: 31614762 PMCID: PMC6835691 DOI: 10.3390/nu11102432] [Citation(s) in RCA: 87] [Impact Index Per Article: 17.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2019] [Revised: 09/30/2019] [Accepted: 10/08/2019] [Indexed: 12/22/2022] Open
Abstract
Aerobic exercise training and resistance exercise training are both well-known for their ability to improve human health; especially in individuals with type 2 diabetes. However, there are critical differences between these two main forms of exercise training and the adaptations that they induce in the body that may account for their beneficial effects. This article reviews the literature and highlights key gaps in our current understanding of the effects of aerobic and resistance exercise training on the regulation of systemic glucose homeostasis, skeletal muscle glucose transport and skeletal muscle glucose metabolism.
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35
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Svenson KL, Long LL, Ciciotte SL, Adams MD. A mutation in mouse Krüppel-like factor 15 alters the gut microbiome and response to obesogenic diet. PLoS One 2019; 14:e0222536. [PMID: 31553739 PMCID: PMC6760833 DOI: 10.1371/journal.pone.0222536] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2019] [Accepted: 08/30/2019] [Indexed: 12/22/2022] Open
Abstract
We identified a mouse strain, HLB444, carrying an N-ethyl-N-nitrosourea (ENU)-induced mutation in a highly conserved C2H2 zinc-finger DNA binding motif of the transcriptional regulator KLF15 that exhibits resistance to diet-induced obesity. Characterization of the HLB444 mutant model on high-fat and chow diets revealed a number of phenotypic differences compared to wild-type controls. When fed a high fat diet, HLB444 had lower body fat, resistance to hepatosteatosis, lower circulating glucose and improved insulin sensitivity compared to C57BL/6J controls. Gut microbial profiles in HLB444 generated from 16S rRNA sequencing of fecal samples differed from controls under both chow and high fat diets. HLB444 shares similar phenotypic traits with engineered full- and adipose-specific Klf15 knockout strains; however, some phenotypic differences between this mutant and the other models suggest that the Klf15 mutation in HLB444 is a hypomorphic variant. The HLB444 model will inform further annotation of transcriptional functions of KLF15, especially with respect to the role of the first zinc-finger domain.
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Affiliation(s)
- Karen L. Svenson
- The Jackson Laboratory, Bar Harbor, Maine, United States of America
| | - Lauren L. Long
- The Jackson Laboratory, Farmington, Connecticut, United States of America
| | | | - Mark D. Adams
- The Jackson Laboratory, Farmington, Connecticut, United States of America
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36
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Figueiredo VC. Revisiting the roles of protein synthesis during skeletal muscle hypertrophy induced by exercise. Am J Physiol Regul Integr Comp Physiol 2019; 317:R709-R718. [PMID: 31508978 DOI: 10.1152/ajpregu.00162.2019] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Protein synthesis is deemed the underpinning mechanism enhancing protein balance required for skeletal muscle hypertrophy in response to resistance exercise. The current model of skeletal muscle hypertrophy induced by resistance training states that the acute increase in the rates of protein synthesis after each bout of resistance exercise is the basis for muscle growth. Within this paradigm, each resistance exercise session would add a specific amount of muscle mass; therefore, muscle hypertrophy could be defined as the result of intermittent and short-lived increases in muscle protein synthesis rates following each resistance exercise session. Although a substantial amount of data has accumulated in the last decades regarding the acute changes in protein synthesis (or translational efficiency) following resistance exercise, considerable gaps on the mechanism of muscle growth still exist. Ribosome biogenesis and translational capacity have emerged as important mediators of skeletal muscle hypertrophy. Recent advances in the field have demonstrated that skeletal muscle hypertrophy is associated with markers of translational capacity and long-term changes in protein synthesis under resting conditions. This review will discuss the caveats of the current model of skeletal muscle hypertrophy induced by resistance training while proposing a working model that takes into consideration the novel data generated by independent laboratories utilizing different methodologies. It is argued, herein, that the role of protein synthesis in the current model of muscle hypertrophy warrants revisiting.
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Affiliation(s)
- Vandré Casagrande Figueiredo
- College of Health Sciences, Department of Rehabilitation Sciences, the Center for Muscle Biology, University of Kentucky, Lexington, Kentucky
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37
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Mathes S, Vanmunster M, Bloch W, Suhr F. Evidence for skeletal muscle fiber type-specific expressions of mechanosensors. Cell Mol Life Sci 2019; 76:2987-3004. [PMID: 30701284 PMCID: PMC11105595 DOI: 10.1007/s00018-019-03026-3] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2018] [Revised: 01/10/2019] [Accepted: 01/23/2019] [Indexed: 01/30/2023]
Abstract
Mechanosensors govern muscle tissue integrity and constitute a subcellular structure known as costameres. Costameres physically link the muscle extracellular matrix to contractile and signaling 'hubs' inside muscle fibers mainly via integrins and are localized beneath sarcolemmas of muscle fibers. Costameres are the main mechanosensors converting mechanical cues into biological events. However, the fiber type-specific costamere architecture in muscles is unexplored. We hypothesized that fiber types differ in the expression of genes coding for costamere components. By coupling laser microdissection to a multiplex tandem qPCR approach, we demonstrate that type 1 and type 2 fibers indeed show substantial differences in their mechanosensor complexes. We confirmed these data by fiber type population-specific protein analysis and confocal microscopy-based localization studies. We further show that knockdown of the costamere gene integrin-linked kinase (Ilk) in muscle precursor cells results in significantly increased slow-myosin-coding Myh7 gene, while the fast-myosin-coding genes Myh1, Myh2, and Myh4 are downregulated. In parallel, protein synthesis-enhancing signaling molecules (p-mTORSer2448, p < 0.05; p-P70S6KThr389, tendency with p < 0.1) were reduced upon Ilk knockdown. However, overexpression of slow type-inducing NFATc1 in muscle precursor cells did not change Ilk or other costamere gene expressions. In addition, we demonstrate fiber type-specific costamere gene regulation upon mechanical loading and unloading conditions. Our data imply that costamere genes, such as Ilk, are involved in the control of muscle fiber characteristics. Further, they identify costameres as muscle fiber type-specific loading management 'hubs' and may explain adaptation differences of muscle fiber types to mechanical (un)loading.
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Affiliation(s)
- Sebastian Mathes
- Department of Molecular and Cellular Sport Medicine, German Sport University Cologne, Cologne, Germany
| | - Mathias Vanmunster
- Exercise Physiology Research Group, Department of Movement Sciences, Biomedical Sciences Group, KU Leuven, Tervuursevest 101, Bus 1500, 3001, Leuven, Belgium
| | - Wilhelm Bloch
- Department of Molecular and Cellular Sport Medicine, German Sport University Cologne, Cologne, Germany
| | - Frank Suhr
- Department of Molecular and Cellular Sport Medicine, German Sport University Cologne, Cologne, Germany.
- Exercise Physiology Research Group, Department of Movement Sciences, Biomedical Sciences Group, KU Leuven, Tervuursevest 101, Bus 1500, 3001, Leuven, Belgium.
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38
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Chaillou T. Ribosome specialization and its potential role in the control of protein translation and skeletal muscle size. J Appl Physiol (1985) 2019; 127:599-607. [DOI: 10.1152/japplphysiol.00946.2018] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
The ribosome is typically viewed as a supramolecular complex with constitutive and invariant capacity in mediating translation of mRNA into protein. This view has been challenged by recent research revealing that ribosome composition could be heterogeneous, and this heterogeneity leads to functional ribosome specialization. This review presents the idea that ribosome heterogeneity results from changes in its various components, including variations in ribosomal protein (RP) composition, posttranslational modifications of RPs, changes in ribosomal-associated proteins, alternative forms of rRNA, and posttranscriptional modifications of rRNAs. Ribosome heterogeneity could be orchestrated at several levels and may depend on numerous factors, such as the subcellular location, cell type, tissue specificity, the development state, cell state, ribosome biogenesis, RP turnover, physiological stimuli, and circadian rhythm. Ribosome specialization represents a completely new concept for the regulation of gene expression. Specialized ribosomes could modulate several aspects of translational control, such as mRNA translation selectivity, translation initiation, translational fidelity, and translation elongation. Recent research indicates that the expression of Rpl3 is markedly increased, while that of Rpl3l is highly reduced during mouse skeletal muscle hypertrophy. Moreover, Rpl3l overexpression impairs the growth and myogenic fusion of myotubes. Although the function of Rpl3 and Rpl3l in the ribosome remains to be clarified, these findings suggest that ribosome specialization may be potentially involved in the control of protein translation and skeletal muscle size. Limited data concerning ribosome specialization are currently available in skeletal muscle. Future investigations have the potential to delineate the function of specialized ribosomes in skeletal muscle.
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Affiliation(s)
- Thomas Chaillou
- School of Health Sciences, Örebro University, Örebro, Sweden
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39
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Boppart MD, Mahmassani ZS. Integrin signaling: linking mechanical stimulation to skeletal muscle hypertrophy. Am J Physiol Cell Physiol 2019; 317:C629-C641. [PMID: 31314586 DOI: 10.1152/ajpcell.00009.2019] [Citation(s) in RCA: 71] [Impact Index Per Article: 14.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
The α7β1-integrin is a transmembrane adhesion protein that connects laminin in the extracellular matrix (ECM) with actin in skeletal muscle fibers. The α7β1-integrin is highly expressed in skeletal muscle and is concentrated at costameres and myotendious junctions, providing the opportunity to transmit longitudinal and lateral forces across the membrane. Studies have demonstrated that α7-integrin subunit mRNA and protein are upregulated following eccentric contractions as a mechanism to reinforce load-bearing structures and resist injury with repeated bouts of exercise. It has been hypothesized for many years that the integrin can also promote protein turnover in a manner that can promote beneficial adaptations with resistance exercise training, including hypertrophy. This review provides basic information about integrin structure and activation and then explores its potential to serve as a critical mechanosensor and activator of muscle protein synthesis and growth. Overall, the hypothesis is proposed that the α7β1-integrin can contribute to mechanical-load induced skeletal muscle growth via an mammalian target of rapamycin complex 1-independent mechanism.
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Affiliation(s)
- Marni D Boppart
- Department of Kinesiology and Community Health, University of Illinois at Urbana-Champaign, Urbana, Illinois.,Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, Illinois
| | - Ziad S Mahmassani
- Department of Physical Therapy and Athletic Training, University of Utah, Salt Lake City, Utah
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40
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Kirby TJ. Mechanosensitive pathways controlling translation regulatory processes in skeletal muscle and implications for adaptation. J Appl Physiol (1985) 2019; 127:608-618. [PMID: 31295035 DOI: 10.1152/japplphysiol.01031.2018] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The ability of myofibers to sense and respond appropriately to mechanical signals is one of the primary determinants of the skeletal muscle phenotype. In response to a change in mechanical load, muscle cells alter their protein metabolism, primarily through the regulation of protein synthesis rate. Protein synthesis rates are determined by both translation efficiency and translational capacity within the muscle. Translational capacity is strongly determined by the ribosome content of the muscle; thus the regulation of ribosomal biogenesis by mechanical inputs has been an area of recent interest. Despite the clear association between mechanical signals and changes in protein metabolism, the molecular pathways that link these events are still not fully elucidated. This review focuses on recent studies looking at how mechanosignaling impacts translational events. The role of impaired mechanotransduction in aging is discussed, as is the connection between age-dependent signaling defects and compromised ribosomal biogenesis during mechanical overload. Finally, emerging evidence suggests that the nucleus can act as a mechanosensitive element and that this mode of mechanotransduction may have an important role in skeletal muscle physiology and adaptation.
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Affiliation(s)
- Tyler J Kirby
- Nancy E. and Peter C. Meinig School of Biomedical Engineering, Cornell University, Ithaca, New York.,Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, New York
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41
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Uddin GM, Zhang L, Shah S, Fukushima A, Wagg CS, Gopal K, Al Batran R, Pherwani S, Ho KL, Boisvenue J, Karwi QG, Altamimi T, Wishart DS, Dyck JRB, Ussher JR, Oudit GY, Lopaschuk GD. Impaired branched chain amino acid oxidation contributes to cardiac insulin resistance in heart failure. Cardiovasc Diabetol 2019; 18:86. [PMID: 31277657 PMCID: PMC6610921 DOI: 10.1186/s12933-019-0892-3] [Citation(s) in RCA: 89] [Impact Index Per Article: 17.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/05/2019] [Accepted: 06/28/2019] [Indexed: 12/31/2022] Open
Abstract
BACKGROUND Branched chain amino acids (BCAA) can impair insulin signaling, and cardiac insulin resistance can occur in the failing heart. We, therefore, determined if cardiac BCAA accumulation occurs in patients with dilated cardiomyopathy (DCM), due to an impaired catabolism of BCAA, and if stimulating cardiac BCAA oxidation can improve cardiac function in mice with heart failure. METHOD For human cohorts of DCM and control, both male and female patients of ages between 22 and 66 years were recruited with informed consent from University of Alberta hospital. Left ventricular biopsies were obtained at the time of transplantation. Control biopsies were obtained from non-transplanted donor hearts without heart disease history. To determine if stimulating BCAA catabolism could lessen the severity of heart failure, C57BL/6J mice subjected to a transverse aortic constriction (TAC) were treated between 1 to 4-week post-surgery with either vehicle or a stimulator of BCAA oxidation (BT2, 40 mg/kg/day). RESULT Echocardiographic data showed a reduction in ejection fraction (54.3 ± 2.3 to 22.3 ± 2.2%) and an enhanced formation of cardiac fibrosis in DCM patients when compared to the control patients. Cardiac BCAA levels were dramatically elevated in left ventricular samples of patients with DCM. Hearts from DCM patients showed a blunted insulin signalling pathway, as indicated by an increase in P-IRS1ser636/639 and its upstream modulator P-p70S6K, but a decrease in its downstream modulators P-AKT ser473 and in P-GSK3β ser9. Cardiac BCAA oxidation in isolated working hearts was significantly enhanced by BT2, compared to vehicle, following either acute or chronic treatment. Treatment of TAC mice with BT2 significantly improved cardiac function in both sham and TAC mice (63.0 ± 1.8 and 56.9 ± 3.8% ejection fraction respectively). Furthermore, P-BCKDH and BCKDK expression was significantly decreased in the BT2 treated groups. CONCLUSION We conclude that impaired cardiac BCAA catabolism and insulin signaling occur in human heart failure, while enhancing BCAA oxidation can improve cardiac function in the failing mouse heart.
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Affiliation(s)
- Golam M Uddin
- Cardiovascular Research Centre, University of Alberta, 423 Heritage Medical Research Centre, Edmonton, T6G 2S2, Canada
| | - Liyan Zhang
- Cardiovascular Research Centre, University of Alberta, 423 Heritage Medical Research Centre, Edmonton, T6G 2S2, Canada
| | - Saumya Shah
- Cardiovascular Research Centre, University of Alberta, 423 Heritage Medical Research Centre, Edmonton, T6G 2S2, Canada
| | - Arata Fukushima
- Cardiovascular Research Centre, University of Alberta, 423 Heritage Medical Research Centre, Edmonton, T6G 2S2, Canada
| | - Cory S Wagg
- Cardiovascular Research Centre, University of Alberta, 423 Heritage Medical Research Centre, Edmonton, T6G 2S2, Canada
| | - Keshav Gopal
- Katz Centre for Pharmacy and Health Research, Faculty of Pharmacy and Pharmaceutical Sciences, University of Alberta, Edmonton, Canada.,Mazankowski Alberta Heart Institute, University of Alberta, Edmonton, Canada.,Alberta Diabetes Institute, University of Alberta, Edmonton, Canada
| | - Rami Al Batran
- Katz Centre for Pharmacy and Health Research, Faculty of Pharmacy and Pharmaceutical Sciences, University of Alberta, Edmonton, Canada.,Mazankowski Alberta Heart Institute, University of Alberta, Edmonton, Canada.,Alberta Diabetes Institute, University of Alberta, Edmonton, Canada
| | - Simran Pherwani
- Cardiovascular Research Centre, University of Alberta, 423 Heritage Medical Research Centre, Edmonton, T6G 2S2, Canada
| | - Kim L Ho
- Cardiovascular Research Centre, University of Alberta, 423 Heritage Medical Research Centre, Edmonton, T6G 2S2, Canada.,Katz Centre for Pharmacy and Health Research, Faculty of Pharmacy and Pharmaceutical Sciences, University of Alberta, Edmonton, Canada
| | - Jamie Boisvenue
- Cardiovascular Research Centre, University of Alberta, 423 Heritage Medical Research Centre, Edmonton, T6G 2S2, Canada
| | - Qutuba G Karwi
- Cardiovascular Research Centre, University of Alberta, 423 Heritage Medical Research Centre, Edmonton, T6G 2S2, Canada.,Department of Pharmacology, College of Medicine, University of Diyala, Diyala, Iraq
| | - Tariq Altamimi
- Cardiovascular Research Centre, University of Alberta, 423 Heritage Medical Research Centre, Edmonton, T6G 2S2, Canada
| | - David S Wishart
- Department of Biological Sciences, University of Alberta, Edmonton, Canada.,Metabolomics Innovation Centre, University of Alberta, Edmonton, Canada
| | - Jason R B Dyck
- Cardiovascular Research Centre, University of Alberta, 423 Heritage Medical Research Centre, Edmonton, T6G 2S2, Canada.,Mazankowski Alberta Heart Institute, University of Alberta, Edmonton, Canada
| | - John R Ussher
- Katz Centre for Pharmacy and Health Research, Faculty of Pharmacy and Pharmaceutical Sciences, University of Alberta, Edmonton, Canada.,Mazankowski Alberta Heart Institute, University of Alberta, Edmonton, Canada.,Alberta Diabetes Institute, University of Alberta, Edmonton, Canada
| | - Gavin Y Oudit
- Cardiovascular Research Centre, University of Alberta, 423 Heritage Medical Research Centre, Edmonton, T6G 2S2, Canada.,Mazankowski Alberta Heart Institute, University of Alberta, Edmonton, Canada.,Divsion of Cardiology, Department of Medicine, University of Alberta, Edmonton, Canada
| | - Gary D Lopaschuk
- Cardiovascular Research Centre, University of Alberta, 423 Heritage Medical Research Centre, Edmonton, T6G 2S2, Canada. .,Mazankowski Alberta Heart Institute, University of Alberta, Edmonton, Canada. .,Alberta Diabetes Institute, University of Alberta, Edmonton, Canada.
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42
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Figeac N, Mohamed AD, Sun C, Schönfelder M, Matallanas D, Garcia-Munoz A, Missiaglia E, Collie-Duguid E, De Mello V, Pobbati AV, Pruller J, Jaka O, Harridge SDR, Hong W, Shipley J, Vargesson N, Zammit PS, Wackerhage H. VGLL3 operates via TEAD1, TEAD3 and TEAD4 to influence myogenesis in skeletal muscle. J Cell Sci 2019; 132:jcs.225946. [PMID: 31138678 PMCID: PMC6633393 DOI: 10.1242/jcs.225946] [Citation(s) in RCA: 42] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2018] [Accepted: 05/03/2019] [Indexed: 12/21/2022] Open
Abstract
VGLL proteins are transcriptional co-factors that bind TEAD family transcription factors to regulate events ranging from wing development in fly, to muscle fibre composition and immune function in mice. Here, we characterise Vgll3 in skeletal muscle. We found that mouse Vgll3 was expressed at low levels in healthy muscle but that its levels increased during hypertrophy or regeneration; in humans, VGLL3 was highly expressed in tissues from patients with various muscle diseases, such as in dystrophic muscle and alveolar rhabdomyosarcoma. Interaction proteomics revealed that VGLL3 bound TEAD1, TEAD3 and TEAD4 in myoblasts and/or myotubes. However, there was no interaction with proteins from major regulatory systems such as the Hippo kinase cascade, unlike what is found for the TEAD co-factors YAP (encoded by YAP1) and TAZ (encoded by WWTR1). Vgll3 overexpression reduced the activity of the Hippo negative-feedback loop, affecting expression of muscle-regulating genes including Myf5, Pitx2 and Pitx3, and genes encoding certain Wnts and IGFBPs. VGLL3 mainly repressed gene expression, regulating similar genes to those regulated by YAP and TAZ. siRNA-mediated Vgll3 knockdown suppressed myoblast proliferation, whereas Vgll3 overexpression strongly promoted myogenic differentiation. However, skeletal muscle was overtly normal in Vgll3-null mice, presumably due to feedback signalling and/or redundancy. This work identifies VGLL3 as a transcriptional co-factor operating with the Hippo signal transduction network to control myogenesis. Summary: VGLL3 interacts with TEAD transcription factors to direct expression of crucial muscle regulatory genes and contribute to the control of skeletal myogenesis.
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Affiliation(s)
- Nicolas Figeac
- Randall Centre for Cell and Molecular Biophysics, King's College London, London SE1 1UL, UK
| | - Abdalla D Mohamed
- School of Medicine, Medical Sciences and Nutrition, University of Aberdeen, Foresterhill, Aberdeen AB25 2ZD, UK.,Institute of Developmental Genetics, Helmholtz Zentrum München, German Research Center for Environment and Health, Ingolstaedter Landstrasse 1, D-85764 Munich/Neuherberg, Germany
| | - Congshan Sun
- Randall Centre for Cell and Molecular Biophysics, King's College London, London SE1 1UL, UK.,Department of Neurology, The Johns Hopkins School of Medicine, Baltimore, MD 21205, USA
| | - Martin Schönfelder
- Faculty of Sport and Health Sciences, Technical University of Munich, Georg-Brauchle-Ring 60, 80992 Munich, Germany
| | - David Matallanas
- Systems Biology Ireland, Conway Institute, Belfield; Dublin 4, Ireland
| | | | - Edoardo Missiaglia
- Institute of Pathology, Lausanne University Hospital (CHUV), 1011 Lausanne, Switzerland
| | - Elaina Collie-Duguid
- University of Aberdeen, Centre for Genome Enabled Biology and Medicine, 23 St Machar Drive, Aberdeen AB24 3RY, UK
| | - Vanessa De Mello
- School of Medicine, Medical Sciences and Nutrition, University of Aberdeen, Foresterhill, Aberdeen AB25 2ZD, UK
| | - Ajaybabu V Pobbati
- Institute of Molecular and Cell Biology, A-STAR, 61 Biopolis Drive, Singapore 138673, Singapore
| | - Johanna Pruller
- Randall Centre for Cell and Molecular Biophysics, King's College London, London SE1 1UL, UK
| | - Oihane Jaka
- Centre for Human and Applied Physiological Sciences, King's College London, London SE1 1UL, UK
| | - Stephen D R Harridge
- Centre for Human and Applied Physiological Sciences, King's College London, London SE1 1UL, UK
| | - Wanjin Hong
- Institute of Molecular and Cell Biology, A-STAR, 61 Biopolis Drive, Singapore 138673, Singapore
| | - Janet Shipley
- Sarcoma Molecular Pathology Team, Divisions of Molecular Pathology and Cancer Therapeutics, Institute of Cancer Research, Surrey, SM2 5NG, UK
| | - Neil Vargesson
- School of Medicine, Medical Sciences and Nutrition, University of Aberdeen, Foresterhill, Aberdeen AB25 2ZD, UK
| | - Peter S Zammit
- Randall Centre for Cell and Molecular Biophysics, King's College London, London SE1 1UL, UK
| | - Henning Wackerhage
- School of Medicine, Medical Sciences and Nutrition, University of Aberdeen, Foresterhill, Aberdeen AB25 2ZD, UK .,Faculty of Sport and Health Sciences, Technical University of Munich, Georg-Brauchle-Ring 60, 80992 Munich, Germany
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43
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Vechetti IJ, Wen Y, Chaillou T, Murach KA, Alimov AP, Figueiredo VC, Dal-Pai-Silva M, McCarthy JJ. Life-long reduction in myomiR expression does not adversely affect skeletal muscle morphology. Sci Rep 2019; 9:5483. [PMID: 30940834 PMCID: PMC6445125 DOI: 10.1038/s41598-019-41476-8] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2018] [Accepted: 03/11/2019] [Indexed: 12/20/2022] Open
Abstract
We generated an inducible, skeletal muscle-specific Dicer knockout mouse to deplete microRNAs in adult skeletal muscle. Following tamoxifen treatment, Dicer mRNA expression was significantly decreased by 87%. Wild-type (WT) and Dicer knockout (KO) mice were subjected to either synergist ablation or hind limb suspension for two weeks. There was no difference in muscle weight with hypertrophy or atrophy between WT and KO groups; however, even with the significant loss of Dicer expression, myomiR (miR-1, -133a and -206) expression was only reduced by 38% on average. We next aged WT and KO mice for ~22 months following Dicer inactivation to determine if myomiR expression would be further reduced over a prolonged timeframe and assess the effects of myomiR depletion on skeletal muscle phenotype. Skeletal muscle Dicer mRNA expression remained significantly decreased by 80% in old KO mice and sequencing of cloned Dicer mRNA revealed the complete absence of the floxed exons in KO skeletal muscle. Despite a further reduction of myomiR expression to ~50% of WT, no change was observed in muscle morphology between WT and KO groups. These results indicate the life-long reduction in myomiR levels did not adversely affect skeletal muscle phenotype and suggest the possibility that microRNA expression is uniquely regulated in skeletal muscle.
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Affiliation(s)
- Ivan J Vechetti
- Department of Physiology, College of Medicine, University of Kentucky, Kentucky, USA
- Center for Muscle Biology University of Kentucky, Lexington, Kentucky, USA
- Department of Morphology, São Paulo State University, Institute of Biosciences, Botucatu, Brazil
| | - Yuan Wen
- Department of Physiology, College of Medicine, University of Kentucky, Kentucky, USA
- Center for Muscle Biology University of Kentucky, Lexington, Kentucky, USA
| | - Thomas Chaillou
- Örebro University, School of Health Sciences, Örebro, Sweden
| | - Kevin A Murach
- Department of Rehabilitation Sciences, College of Health Sciences, Kentucky, USA
- Center for Muscle Biology University of Kentucky, Lexington, Kentucky, USA
| | - Alexander P Alimov
- Department of Physiology, College of Medicine, University of Kentucky, Kentucky, USA
- Center for Muscle Biology University of Kentucky, Lexington, Kentucky, USA
| | - Vandre C Figueiredo
- Department of Physiology, College of Medicine, University of Kentucky, Kentucky, USA
- Department of Rehabilitation Sciences, College of Health Sciences, Kentucky, USA
- Center for Muscle Biology University of Kentucky, Lexington, Kentucky, USA
| | - Maeli Dal-Pai-Silva
- Department of Morphology, São Paulo State University, Institute of Biosciences, Botucatu, Brazil
| | - John J McCarthy
- Department of Physiology, College of Medicine, University of Kentucky, Kentucky, USA.
- Center for Muscle Biology University of Kentucky, Lexington, Kentucky, USA.
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44
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Mahmassani ZS, Reidy PT, McKenzie AI, Stubben C, Howard MT, Drummond MJ. Age-dependent skeletal muscle transcriptome response to bed rest-induced atrophy. J Appl Physiol (1985) 2019; 126:894-902. [PMID: 30605403 DOI: 10.1152/japplphysiol.00811.2018] [Citation(s) in RCA: 40] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Short-term muscle disuse induces significant muscle loss in older adults and in some reports may be more accelerated with aging. Identifying muscle transcriptional events in response to bed rest may help identify therapeutic targets to offset muscle loss. Therefore, we compared the muscle transcriptome between young and older adults after bed rest and identified candidate targets related to changes in muscle loss. RNA was sequenced (HiSeq, Illumina; DESeq, R) from muscle biopsies obtained from young [ n = 9; 23 yr (SD 3)] and older [ n = 18; 68 yr (SD 6)] adults before and after 5-day bed rest. Significantly altered pathways in both young and old subjects relating to mechanosensing and cell adhesion (Actin Cytoskeleton Signaling, ILK Signaling, RhoA Signaling, and Integrin Signaling) were altered (activation z score) to a greater extent in old subjects. Hepatic Fibrosis/Hepatic Stellate Cell Activation was the top regulated pathway significantly altered only in the old. Fifty-one differentially regulated genes were only altered in the young after bed rest and resembled a gene expression profile like that in the old at baseline. Inflammation and muscle wasting genes (CXCL2, GADD45A) were uniquely increased in the old after bed rest, and the macrophage gene MAFB decreased in the old and correlated with the change in leg lean mass. In summary, skeletal muscle dysregulation during bed rest in the old may be driven by alterations in molecules related to fibrosis, inflammation, and cell adhesion. This information may aid in the development of mechanistic-based therapies to combat muscle atrophy during short-term disuse. NEW & NOTEWORTHY Using RNA sequencing and bioinformatics approaches, we identified that older adult skeletal muscle was characterized by dysregulated pathways associated with fibrosis, inflammation (upregulated), and cell adhesion and mechanosensing (downregulated) pathways, with a subset of genes differentially regulated in old and young muscle after bed rest that may describe predisposition to muscle loss. Unique upregulated genes only expressed in old muscle after bed rest indicated increased inflammation and muscle wasting (CXCL2, GADD45A) and decreased MAFB correlated with the change in leg lean mass.
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Affiliation(s)
- Ziad S Mahmassani
- Department of Physical Therapy and Athletic Training, University of Utah , Salt Lake City, Utah
| | - Paul T Reidy
- Department of Physical Therapy and Athletic Training, University of Utah , Salt Lake City, Utah
| | - Alec I McKenzie
- Department of Physical Therapy and Athletic Training, University of Utah , Salt Lake City, Utah
| | - Chris Stubben
- Bioinformatics Shared Resource at the Huntsman Cancer Institute , Salt Lake City, Utah
| | - Michael T Howard
- Department of Genetics, University of Utah , Salt Lake City, Utah
| | - Micah J Drummond
- Department of Physical Therapy and Athletic Training, University of Utah , Salt Lake City, Utah
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45
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Figueiredo VC, McCarthy JJ. Regulation of Ribosome Biogenesis in Skeletal Muscle Hypertrophy. Physiology (Bethesda) 2019; 34:30-42. [PMID: 30540235 PMCID: PMC6383632 DOI: 10.1152/physiol.00034.2018] [Citation(s) in RCA: 80] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2018] [Revised: 09/11/2018] [Accepted: 09/13/2018] [Indexed: 01/22/2023] Open
Abstract
The ribosome is the enzymatic macromolecular machine responsible for protein synthesis. The rates of protein synthesis are primarily dependent on translational efficiency and capacity. Ribosome biogenesis has emerged as an important regulator of skeletal muscle growth and maintenance by altering the translational capacity of the cell. Here, we provide evidence to support a central role for ribosome biogenesis in skeletal muscle growth during postnatal development and in response to resistance exercise training. Furthermore, we discuss the cellular signaling pathways regulating ribosome biogenesis, discuss how myonuclear accretion affects translational capacity, and explore future areas of investigation within the field.
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Affiliation(s)
- Vandré Casagrande Figueiredo
- The Center for Muscle Biology, College of Health Sciences, University of Kentucky , Lexington, Kentucky
- Department of Rehabilitation Sciences, College of Medicine, University of Kentucky , Lexington, Kentucky
| | - John J McCarthy
- The Center for Muscle Biology, College of Health Sciences, University of Kentucky , Lexington, Kentucky
- Department of Physiology, University of Kentucky , Lexington, Kentucky
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46
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Abstract
The last decade has seen a dramatic increase in general interest in and research into vitamin D, with many athletes now taking vitamin D supplements as part of their everyday dietary regimen. The most recognized role of vitamin D is its regulation of calcium homeostasis; there is a strong relationship between vitamin D and bone health in non-athletic individuals. In contrast, data have consistently failed to demonstrate any relationship between serum 25[OH]D and bone health, which may in part be due to the osteogenic stimulus of exercise. Vitamin D may interact with extra-skeletal tissues such as muscle and the immune system to modulate recovery from damaging exercise and infection risk. Given that many athletes now engage in supplementation, often consuming extreme doses of vitamin D, it is important to assess whether excessive vitamin D can be detrimental to health. It has been argued that toxic effects only occur when serum 25[OH]D concentrations are greater than 180 nmol·l-1, but data from our laboratory have suggested high-dose supplementation could be problematic. Finally, there is a paradoxical relationship between serum 25[OH]D concentration, ethnicity, and markers of bone health: Black athletes often present with low serum 25[OH]D without physiological consequences. One explanation for this could be genetic differences in vitamin D binding protein due to ethnicity, resulting in greater concentrations of bioavailable (or free) vitamin D in some ethnic groups. In the absence of any pathology, screening may be unnecessary and could result in incorrect supplementation. Data must now be re-examined, taking into consideration bioavailable or "free" vitamin D in ethnically diverse groups to enable new thresholds and target concentrations to be established; perhaps, for now, it is time to "set vitamin D free".
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Affiliation(s)
- Daniel J Owens
- Research Institute for Sport and Exercise Science, Liverpool John Moores University, Tom Reilly Building, Byrom Street, Liverpool, L3 3AF, UK
| | - Richard Allison
- Research Institute for Sport and Exercise Science, Liverpool John Moores University, Tom Reilly Building, Byrom Street, Liverpool, L3 3AF, UK.,Exercise and Sport Science Department, ASPETAR, Orthopaedic and Sports Medicine Hospital, Doha, Qatar.,Arsenal Football Club, Bell Lane, London Colney, St Albans, Shenley, AL2 1DR, UK
| | - Graeme L Close
- Research Institute for Sport and Exercise Science, Liverpool John Moores University, Tom Reilly Building, Byrom Street, Liverpool, L3 3AF, UK.
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47
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Wackerhage H, Schoenfeld BJ, Hamilton DL, Lehti M, Hulmi JJ. Stimuli and sensors that initiate skeletal muscle hypertrophy following resistance exercise. J Appl Physiol (1985) 2018; 126:30-43. [PMID: 30335577 DOI: 10.1152/japplphysiol.00685.2018] [Citation(s) in RCA: 152] [Impact Index Per Article: 25.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
One of the most striking adaptations to exercise is the skeletal muscle hypertrophy that occurs in response to resistance exercise. A large body of work shows that a mammalian target of rapamycin complex 1 (mTORC1)-mediated increase of muscle protein synthesis is the key, but not sole, mechanism by which resistance exercise causes muscle hypertrophy. While much of the hypertrophy signaling cascade has been identified, the initiating, resistance exercise-induced and hypertrophy-stimulating stimuli have remained elusive. For the purpose of this review, we define an initiating, resistance exercise-induced and hypertrophy-stimulating signal as "hypertrophy stimulus," and the sensor of such a signal as "hypertrophy sensor." In this review we discuss our current knowledge of specific mechanical stimuli, damage/injury-associated and metabolic stress-associated triggers, as potential hypertrophy stimuli. Mechanical signals are the prime hypertrophy stimuli candidates, and a filamin-C-BAG3-dependent regulation of mTORC1, Hippo, and autophagy signaling is a plausible albeit still incompletely characterized hypertrophy sensor. Other candidate mechanosensing mechanisms are nuclear deformation-initiated signaling or several mechanisms related to costameres, which are the functional equivalents of focal adhesions in other cells. While exercise-induced muscle damage is probably not essential for hypertrophy, it is still unclear whether and how such muscle damage could augment a hypertrophic response. Interventions that combine blood flow restriction and especially low load resistance exercise suggest that resistance exercise-regulated metabolites could be hypertrophy stimuli, but this is based on indirect evidence and metabolite candidates are poorly characterized.
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Affiliation(s)
- Henning Wackerhage
- Department of Sport and Exercise Sciences, Technical University of Munich , Munich , Germany
| | | | - D Lee Hamilton
- Faculty of Health, School of Exercise and Nutrition Sciences, Deakin University , Victoria , Australia
| | - Maarit Lehti
- LIKES Research Centre for Physical Activity and Health , Jyväskylä , Finland
| | - Juha J Hulmi
- Neuromuscular Research Center, Biology of Physical Activity, Faculty of Sport and Health Sciences, University of Jyväskylä , Jyväskylä , Finland
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48
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Sosa P, Alcalde-Estevez E, Plaza P, Troyano N, Alonso C, Martínez-Arias L, Evelem de Melo Aroeira A, Rodriguez-Puyol D, Olmos G, López-Ongil S, Ruíz-Torres MP. Hyperphosphatemia Promotes Senescence of Myoblasts by Impairing Autophagy Through Ilk Overexpression, A Possible Mechanism Involved in Sarcopenia. Aging Dis 2018; 9:769-784. [PMID: 30271655 PMCID: PMC6147593 DOI: 10.14336/ad.2017.1214] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2017] [Accepted: 12/14/2017] [Indexed: 12/28/2022] Open
Abstract
In mammalians, advancing age is associated with sarcopenia, the progressive and involuntary loss of muscle mass and strength. Hyperphosphatemia is an aging-related condition involved in several pathologies. The aim of this work was to assess whether hyperphosphatemia plays a role in the age-related loss of mass muscle and strength by inducing cellular senescence in murine myoblasts and to explore the intracellular mechanism involved in this effect. Cultured mouse C2C12 cells were treated with 10 mM beta-glycerophosphate (BGP] at different periods of time to induce hyperphosphatemia. BGP promoted cellular senescence after 24 h of treatment, assessed by the increased expression of p53, acetylated-p53 and p21 and senescence associated β-galactosidase activity. In parallel, BGP increased ILK expression and activity, followed by mTOR activation and autophagy reduction. Knocking-down ILK expression increased autophagy and protected cells from senescence induced by hyperphosphatemia. BGP also reduced the proliferative capacity of cultured myoblasts. Old mice (24-months-old] presented higher serum phosphate concentration, lower forelimb strength, higher expression of p53 and ILK and less autophagy in vastus muscle than young mice (5-months-old]. In conclusion, we propose that hyperphosphatemia induces senescence in cultured myoblasts through ILK overexpression, reducing their proliferative capacity, which could be a mechanism involved in the development of sarcopenia, since old mice showed loss of muscular strength correlated with high serum phosphate concentration and increased levels of ILK and p53.
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Affiliation(s)
- Patricia Sosa
- System Biology Department, Alcala University, Alcalá de Henares, Madrid, Spain.
| | - Elena Alcalde-Estevez
- System Biology Department, Alcala University, Alcalá de Henares, Madrid, Spain.
- Research Unit, Biomedical Research Foundation from Príncipe de Asturias University Hospital, Alcalá de Henares, Madrid, Spain.
| | - Patricia Plaza
- System Biology Department, Alcala University, Alcalá de Henares, Madrid, Spain.
| | - Nuria Troyano
- System Biology Department, Alcala University, Alcalá de Henares, Madrid, Spain.
| | - Cristina Alonso
- Geriatric and Frailty Section, Getafe University Hospital, Getafe, Madrid, Spain.
| | - Laura Martínez-Arias
- Bone and Mineral Research Unit, Hospital Universitario Central de Asturias. Instituto de Investigación Sanitaria del Principado de Asturias, Red de Investigación Renal (REDinREN] del ISCIII, Oviedo, Spain
| | | | - Diego Rodriguez-Puyol
- Research Unit, Biomedical Research Foundation from Príncipe de Asturias University Hospital, Alcalá de Henares, Madrid, Spain.
- Nephrology Section, Biomedical Research Foundation from Principe de Asturias University Hospital, Alcalá de Henares, Madrid, Spain
- Instituto Reina Sofía de Investigación Nefrológica, IRSIN, Madrid, Spain.
| | - Gemma Olmos
- System Biology Department, Alcala University, Alcalá de Henares, Madrid, Spain.
- Instituto Reina Sofía de Investigación Nefrológica, IRSIN, Madrid, Spain.
| | - Susana López-Ongil
- Research Unit, Biomedical Research Foundation from Príncipe de Asturias University Hospital, Alcalá de Henares, Madrid, Spain.
- Instituto Reina Sofía de Investigación Nefrológica, IRSIN, Madrid, Spain.
| | - María P. Ruíz-Torres
- System Biology Department, Alcala University, Alcalá de Henares, Madrid, Spain.
- Instituto Reina Sofía de Investigación Nefrológica, IRSIN, Madrid, Spain.
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49
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Wen Y, Alimov AP, McCarthy JJ. Ribosome Biogenesis is Necessary for Skeletal Muscle Hypertrophy. Exerc Sport Sci Rev 2018; 44:110-5. [PMID: 27135313 DOI: 10.1249/jes.0000000000000082] [Citation(s) in RCA: 55] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Affiliation(s)
- Yuan Wen
- 1Department of Physiology, 2Center for Muscle Biology, and 3College of Medicine, University of Kentucky, Lexington, KY
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50
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Roberts MD, Romero MA, Mobley CB, Mumford PW, Roberson PA, Haun CT, Vann CG, Osburn SC, Holmes HH, Greer RA, Lockwood CM, Parry HA, Kavazis AN. Skeletal muscle mitochondrial volume and myozenin-1 protein differences exist between high versus low anabolic responders to resistance training. PeerJ 2018; 6:e5338. [PMID: 30065891 PMCID: PMC6065464 DOI: 10.7717/peerj.5338] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2018] [Accepted: 07/09/2018] [Indexed: 12/22/2022] Open
Abstract
Background We sought to examine how 12 weeks of resistance exercise training (RET) affected skeletal muscle myofibrillar and sarcoplasmic protein levels along with markers of mitochondrial physiology in high versus low anabolic responders. Methods Untrained college-aged males were classified as anabolic responders in the top 25th percentile (high-response cluster (HI); n = 13, dual x-ray absorptiometry total body muscle mass change (Δ) = +3.1 ± 0.3 kg, Δ vastus lateralis (VL) thickness = +0.59 ± 0.05 cm, Δ muscle fiber cross sectional area = +1,426 ± 253 μm2) and bottom 25th percentile (low-response cluster (LO); n = 12, +1.1 ± 0.2 kg, +0.24 ± 0.07 cm, +5 ± 209 μm2; p < 0.001 for all Δ scores compared to HI). VL muscle prior to (PRE) and following RET (POST) was assayed for myofibrillar and sarcoplasmic protein concentrations, myosin and actin protein content, and markers of mitochondrial volume. Proteins related to myofibril formation, as well as whole lysate PGC1-α protein levels were assessed. Results Main effects of cluster (HI > LO, p = 0.018, Cohen’s d = 0.737) and time (PRE > POST, p = 0.037, Cohen’s d = −0.589) were observed for citrate synthase activity, although no significant interaction existed (LO PRE = 1.35 ± 0.07 mM/min/mg protein, LO POST = 1.12 ± 0.06, HI PRE = 1.53 ± 0.11, HI POST = 1.39 ± 0.10). POST myofibrillar myozenin-1 protein levels were up-regulated in the LO cluster (LO PRE = 0.96 ± 0.13 relative expression units, LO POST = 1.25 ± 0.16, HI PRE = 1.00 ± 0.11, HI POST = 0.85 ± 0.12; within-group LO increase p = 0.025, Cohen’s d = 0.691). No interactions or main effects existed for other assayed markers. Discussion Our data suggest myofibrillar or sarcoplasmic protein concentrations do not differ between HI versus LO anabolic responders prior to or following a 12-week RET program. Greater mitochondrial volume in HI responders may have facilitated greater anabolism, and myofibril myozenin-1 protein levels may represent a biomarker that differentiates anabolic responses to RET. However, mechanistic research validating these hypotheses is needed.
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Affiliation(s)
| | | | | | | | | | - Cody T Haun
- School of Kinesiology, Auburn University, Auburn, AL, USA
| | | | | | | | - Rory A Greer
- School of Kinesiology, Auburn University, Auburn, AL, USA
| | | | - Hailey A Parry
- School of Kinesiology, Auburn University, Auburn, AL, USA
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