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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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2
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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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3
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Mechanobiology-based physical therapy and rehabilitation after orthobiologic interventions: a narrative review. INTERNATIONAL ORTHOPAEDICS 2021; 46:179-188. [PMID: 34709429 DOI: 10.1007/s00264-021-05253-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/01/2020] [Accepted: 10/19/2021] [Indexed: 10/20/2022]
Abstract
PURPOSE This review aims to summarize the evidence for the role of mechanotherapies and rehabilitation in supporting the synergy between regeneration and repair after an orthobiologic intervention. METHODS A selective literature search was performed using Web of Science, OVID, and PubMed to review research articles that discuss the effects of combining mechanotherapy with various forms of regenerative medicine. RESULTS Various mechanotherapies can encourage the healing process for patients at different stages. Taping, bracing, cold water immersion, and extracorporeal shockwave therapy can be used throughout the duration of acute inflammatory response. The regulation of angiogenesis can be sustained with blood flow restriction and resistance training, whereas heat therapy and tissue loading during exercise are recommended in the remodeling phase. CONCLUSION Combining mechanotherapy with various forms of regenerative medicine has shown promise for improving treatment outcomes. However, further studies that reveal a greater volume of evidence are needed to support clinical decisions.
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The Role of Satellite Cells in Skeletal Muscle Regeneration-The Effect of Exercise and Age. BIOLOGY 2021; 10:biology10101056. [PMID: 34681155 PMCID: PMC8533525 DOI: 10.3390/biology10101056] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/27/2021] [Revised: 10/05/2021] [Accepted: 10/12/2021] [Indexed: 12/03/2022]
Abstract
Simple Summary Studies describing the effects of various forms of exercise and age on muscle regeneration were reviewed. Satellite cells are a heterogeneous group of cells that includes stem cells and skeletal muscle progenitor cells. Each skeletal muscle fiber has its own pool of satellite cells that remain inactive until the muscle is damaged. Minor damage within the cell membrane of muscle fibers is patched by fusing intracellular vesicles with the damaged sarcolemma. More severe muscle damage initiates a multistep regeneration process in which satellite cells play an essential role. The condition that initiates the cascade of reactions is the formation of inflammation at the structural discontinuity site, resulting in satellite cell activation. The multitude of reactions and pathways occurring during this process means that many different substances are involved in it and control it. Not all of them are well-understood yet. In parallel, the body’s own population of satellite cells is being rebuilt so that more fibers can be regenerated in the future. Athletes and the elderly are primarily at risk for muscle damage, and pathologies in muscle fiber regeneration cause serious diseases. Abstract The population of satellite cells (mSCs) is highly diversified. The cells comprising it differ in their ability to regenerate their own population and differentiate, as well as in the properties they exhibit. The heterogeneity of this group of cells is evidenced by multiple differentiating markers that enable their recognition, classification, labeling, and characterization. One of the main tasks of satellite cells is skeletal muscle regeneration. Myofibers are often damaged during vigorous exercise in people who participate in sports activities. The number of satellite cells and the speed of the regeneration processes that depend on them affect the time structure of an athlete’s training. This process depends on inflammatory cells. The multitude of reactions and pathways that occur during the regeneration process results in the participation and control of many factors that are activated and secreted during muscle fiber damage and at different stages of its regeneration. However, not all of them are well understood yet. This paper presents the current state of knowledge on satellite cell-dependent skeletal muscle regeneration. Studies describing the effects of various forms of exercise and age on this process were reviewed.
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Murach KA, Fry CS, Dupont-Versteegden EE, McCarthy JJ, Peterson CA. Fusion and beyond: Satellite cell contributions to loading-induced skeletal muscle adaptation. FASEB J 2021; 35:e21893. [PMID: 34480776 PMCID: PMC9293230 DOI: 10.1096/fj.202101096r] [Citation(s) in RCA: 40] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2021] [Revised: 08/13/2021] [Accepted: 08/17/2021] [Indexed: 12/14/2022]
Abstract
Satellite cells support adult skeletal muscle fiber adaptations to loading in numerous ways. The fusion of satellite cells, driven by cell-autonomous and/or extrinsic factors, contributes new myonuclei to muscle fibers, associates with load-induced hypertrophy, and may support focal membrane damage repair and long-term myonuclear transcriptional output. Recent studies have also revealed that satellite cells communicate within their niche to mediate muscle remodeling in response to resistance exercise, regulating the activity of numerous cell types through various mechanisms such as secretory signaling and cell-cell contact. Muscular adaptation to resistance and endurance activity can be initiated and sustained for a period of time in the absence of satellite cells, but satellite cell participation is ultimately required to achieve full adaptive potential, be it growth, function, or proprioceptive coordination. While significant progress has been made in understanding the roles of satellite cells in adult muscle over the last few decades, many conclusions have been extrapolated from regeneration studies. This review highlights our current understanding of satellite cell behavior and contributions to adaptation outside of regeneration in adult muscle, as well as the roles of satellite cells beyond fusion and myonuclear accretion, which are gaining broader recognition.
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Affiliation(s)
- Kevin A Murach
- The Center for Muscle Biology, University of Kentucky, Lexington, Kentucky, USA.,Molecular Muscle Mass Regulation Laboratory, Exercise Science Research Center, Department of Health, Human Performance, and Recreation, University of Arkansas, Fayetteville, Arkansas, USA.,Cell and Molecular Biology Program, University of Arkansas, Fayetteville, Arkansas, USA
| | - Christopher S Fry
- The Center for Muscle Biology, University of Kentucky, Lexington, Kentucky, USA.,Department of Athletic Training and Clinical Nutrition, College of Health Sciences, University of Kentucky, Lexington, Kentucky, USA
| | - Esther E Dupont-Versteegden
- The Center for Muscle Biology, University of Kentucky, Lexington, Kentucky, USA.,Department of Physical Therapy, College of Health Sciences, University of Kentucky, Lexington, Kentucky, USA
| | - John J McCarthy
- The Center for Muscle Biology, University of Kentucky, Lexington, Kentucky, USA.,Department of Physiology, College of Medicine, University of Kentucky, Lexington, Kentucky, USA
| | - Charlotte A Peterson
- The Center for Muscle Biology, University of Kentucky, Lexington, Kentucky, USA.,Department of Physical Therapy, College of Health Sciences, University of Kentucky, Lexington, Kentucky, USA.,Department of Physiology, College of Medicine, University of Kentucky, Lexington, Kentucky, USA
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6
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Wen Y, Dungan CM, Mobley CB, Valentino T, von Walden F, Murach KA. Nucleus Type-Specific DNA Methylomics Reveals Epigenetic "Memory" of Prior Adaptation in Skeletal Muscle. FUNCTION (OXFORD, ENGLAND) 2021; 2:zqab038. [PMID: 34870208 PMCID: PMC8636928 DOI: 10.1093/function/zqab038] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/14/2021] [Revised: 07/28/2021] [Accepted: 08/03/2021] [Indexed: 02/07/2023]
Abstract
Using a mouse model of conditional and inducible in vivo fluorescent myonuclear labeling (HSA-GFP), sorting purification of nuclei, low-input reduced representation bisulfite sequencing (RRBS), and a translatable and reversible model of exercise (progressive weighted wheel running, PoWeR), we provide the first nucleus type-specific epigenetic information on skeletal muscle adaptation and detraining. Adult (>4 mo) HSA-GFP mice performed PoWeR for 8 wk then detrained for 12 wk; age-matched untrained mice were used to control for the long duration of the study. Myonuclei and interstitial nuclei from plantaris muscles were isolated for RRBS. Relative to untrained, PoWeR caused similar myonuclear CpG hypo- and hyper-methylation of promoter regions and substantial hypomethylation in interstitial nuclear promoters. Over-representation analysis of promoters revealed a larger number of hyper- versus hypo-methylated pathways in both nuclear populations after training and evidence for reciprocal regulation of methylation between nucleus types, with hypomethylation of promoter regions in Wnt signaling-related genes in myonuclei and hypermethylation in interstitial nuclei. After 12 wk of detraining, promoter CpGs in documented muscle remodeling-associated genes and pathways that were differentially methylated immediately after PoWeR were persistently differentially methylated in myonuclei, along with long-term promoter hypomethylation in interstitial nuclei. No enduring gene expression changes in muscle tissue were observed using RNA-sequencing. Upon 4 wk of retraining, mice that trained previously grew more at the whole muscle and fiber type-specific cellular level than training naïve mice, with no difference in myonuclear number. Muscle nuclei have a methylation epi-memory of prior training that may augment muscle adaptability to retraining.
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Affiliation(s)
- Yuan Wen
- Department of Physiology, University of Kentucky, Lexington, KY 40508, USA,The Center for Muscle Biology, University of Kentucky, Lexington, KY 40536, USA
| | - Cory M Dungan
- The Center for Muscle Biology, University of Kentucky, Lexington, KY 40536, USA,College of Health Sciences, University of Kentucky, Lexington, KY 40536, USA
| | - C Brooks Mobley
- Department of Physiology, University of Kentucky, Lexington, KY 40508, USA,The Center for Muscle Biology, University of Kentucky, Lexington, KY 40536, USA
| | - Taylor Valentino
- Department of Physiology, University of Kentucky, Lexington, KY 40508, USA,The Center for Muscle Biology, University of Kentucky, Lexington, KY 40536, USA
| | - Ferdinand von Walden
- Division of Pediatric Neurology, Department of Women's and Children's Health, Karolinska Institutet, Stockholm 171 77, Sweden
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7
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Shamim B, Camera DM, Whitfield J. Myofibre Hypertrophy in the Absence of Changes to Satellite Cell Content Following Concurrent Exercise Training in Young Healthy Men. Front Physiol 2021; 12:625044. [PMID: 34149439 PMCID: PMC8213074 DOI: 10.3389/fphys.2021.625044] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2020] [Accepted: 05/11/2021] [Indexed: 12/17/2022] Open
Abstract
Concurrent exercise training has been suggested to create an ‘interference effect,’ attenuating resistance training-based skeletal muscle adaptations, including myofibre hypertrophy. Satellite cells support myofibre hypertrophy and are influenced by exercise mode. To determine whether satellite cells contribute to the ‘interference effect’ changes in satellite cell and myonuclear content were assessed following a period of training in 32 recreationally active males (age: 25 ± 5 year; body mass index: 24 ± 3 kg⋅m–2; mean ± SD) who undertook 12-week of either isolated (3 d⋅w–1) resistance (RES; n = 10), endurance (END; n = 10), or alternate day (6 d⋅w–1) concurrent (CET, n = 12) training. Skeletal muscle biopsies were obtained pre-intervention and after 2, 8, and 12 weeks of training to determine fibre type-specific cross-sectional area (CSA), satellite cell content (Pax7+DAPI+), and myonuclei (DAPI+) using immunofluorescence microscopy. After 12 weeks, myofibre CSA increased in all training conditions in type II (P = 0.0149) and mixed fibres (P = 0.0102), with no difference between conditions. Satellite cell content remained unchanged after training in both type I and type II fibres. Significant correlations were observed between increases in fibre type-specific myonuclear content and CSA of Type I (r = 0.63, P < 0.0001), Type II (r = 0.69, P < 0.0001), and mixed fibres (r = 0.72, P < 0.0001). Resistance, endurance, and concurrent training induce similar myofibre hypertrophy in the absence of satellite cell and myonuclear pool expansion. These findings suggest that myonuclear accretion via satellite cell fusion is positively correlated with hypertrophy after 12 weeks of concurrent training, and that individuals with more myonuclear content displayed greater myofibre hypertrophy.
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Affiliation(s)
- Baubak Shamim
- Exercise and Nutrition Research Programme, Mary MacKillop Institute for Health Research, Australian Catholic University, Melbourne, VIC, Australia
| | - Donny M Camera
- Exercise and Nutrition Research Programme, Mary MacKillop Institute for Health Research, Australian Catholic University, Melbourne, VIC, Australia
| | - Jamie Whitfield
- Exercise and Nutrition Research Programme, Mary MacKillop Institute for Health Research, Australian Catholic University, Melbourne, VIC, Australia
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8
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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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9
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Dungan CM, Peck BD, Walton RG, Huang Z, Bamman MM, Kern PA, Peterson CA. In vivo analysis of γH2AX+ cells in skeletal muscle from aged and obese humans. FASEB J 2020; 34:7018-7035. [PMID: 32246795 DOI: 10.1096/fj.202000111rr] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2020] [Revised: 03/12/2020] [Accepted: 03/17/2020] [Indexed: 12/25/2022]
Abstract
Over the past 20 years, various identifiers of cellular senescence have been used to quantify the abundance of these cells in different tissues. These include classic markers such as p16, senescence-associated β-gal, and γH2AX, in addition to more recent markers (Sudan Black B and HMGB1). In vivo data on the usefulness of these markers in skeletal muscle are very limited and inconsistent. In the present study, we attempted to identify senescent cells in frozen human skeletal muscle biopsies using these markers to determine the effects of age and obesity on senescent cell burden; however, we were only able to assess the abundance of DNA-damaged nuclei using γH2AX immunohistochemistry. The abundance of γH2AX+ cells, including satellite cells, was not higher in muscle from old compared to young individuals; however, γH2AX+ cells were higher with obesity. Additionally, terminally differentiated, postmitotic myofiber nuclei from obese individuals had elevated γH2AX abundance compared to muscle from lean individuals. Analyses of gene expression support the conclusion that the elevated DNA damage and the senescence-associated secretory phenotype are preferentially associated with obesity in skeletal muscle. These data implicate obesity as a larger contributor to DNA damage in skeletal muscle than aging; however, more sensitive senescence markers for human skeletal muscle are needed to determine if these cells are in fact senescent.
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Affiliation(s)
- Cory M Dungan
- Department of Physical Therapy, College of Health Sciences, University of Kentucky, Lexington, KY, USA.,Center for Muscle Biology, University of Kentucky, Lexington, KY, USA
| | - Bailey D Peck
- Department of Physical Therapy, College of Health Sciences, University of Kentucky, Lexington, KY, USA.,Center for Muscle Biology, University of Kentucky, Lexington, KY, USA
| | - R Grace Walton
- Department of Physical Therapy, College of Health Sciences, University of Kentucky, Lexington, KY, USA.,Center for Muscle Biology, University of Kentucky, Lexington, KY, USA
| | - Zhengyan Huang
- Department of Biostatistics, College of Public Health, University of Kentucky, Lexington, KY, USA
| | - Marcas M Bamman
- Department of Cell, Developmental, and Integrative Biology, School of Medicine, University of Alabama, Birmingham, AL, USA.,Geriatric Research, Education, and Clinical Center, Birmingham VA Medical Center, Birmingham, AL, USA
| | - Philip A Kern
- Department of Internal Medicine/Endocrinology, College of Medicine, University of Kentucky, Lexington, KY, USA
| | - Charlotte A Peterson
- Department of Physical Therapy, College of Health Sciences, University of Kentucky, Lexington, KY, USA.,Center for Muscle Biology, University of Kentucky, Lexington, KY, USA
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10
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Joanisse S, Lim C, McKendry J, Mcleod JC, Stokes T, Phillips SM. Recent advances in understanding resistance exercise training-induced skeletal muscle hypertrophy in humans. F1000Res 2020; 9. [PMID: 32148775 PMCID: PMC7043134 DOI: 10.12688/f1000research.21588.1] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 02/18/2020] [Indexed: 12/22/2022] Open
Abstract
Skeletal muscle plays a pivotal role in the maintenance of physical and metabolic health and, critically, mobility. Accordingly, strategies focused on increasing the quality and quantity of skeletal muscle are relevant, and resistance exercise is foundational to the process of functional hypertrophy. Much of our current understanding of skeletal muscle hypertrophy can be attributed to the development and utilization of stable isotopically labeled tracers. We know that resistance exercise and sufficient protein intake act synergistically and provide the most effective stimuli to enhance skeletal muscle mass; however, the molecular intricacies that underpin the tremendous response variability to resistance exercise-induced hypertrophy are complex. The purpose of this review is to discuss recent studies with the aim of shedding light on key regulatory mechanisms that dictate hypertrophic gains in skeletal muscle mass. We also aim to provide a brief up-to-date summary of the recent advances in our understanding of skeletal muscle hypertrophy in response to resistance training in humans.
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Affiliation(s)
- Sophie Joanisse
- Exercise Metabolism Research Group, Department of Kinesiology, McMaster University, Hamilton, ON, Canada
| | - Changhyun Lim
- Exercise Metabolism Research Group, Department of Kinesiology, McMaster University, Hamilton, ON, Canada
| | - James McKendry
- Exercise Metabolism Research Group, Department of Kinesiology, McMaster University, Hamilton, ON, Canada
| | - Jonathan C Mcleod
- Exercise Metabolism Research Group, Department of Kinesiology, McMaster University, Hamilton, ON, Canada
| | - Tanner Stokes
- Exercise Metabolism Research Group, Department of Kinesiology, McMaster University, Hamilton, ON, Canada
| | - Stuart M Phillips
- Exercise Metabolism Research Group, Department of Kinesiology, McMaster University, Hamilton, ON, Canada
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11
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Wu J, Saovieng S, Cheng IS, Jensen J, Jean WH, Alkhatib A, Kao CL, Huang CY, Kuo CH. Satellite cells depletion in exercising human skeletal muscle is restored by ginseng component Rg1 supplementation. J Funct Foods 2019. [DOI: 10.1016/j.jff.2019.04.032] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
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12
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Dungan CM, Murach KA, Frick KK, Jones SR, Crow SE, Englund DA, Vechetti IJ, Figueiredo VC, Levitan BM, Satin J, McCarthy JJ, Peterson CA. Elevated myonuclear density during skeletal muscle hypertrophy in response to training is reversed during detraining. Am J Physiol Cell Physiol 2019; 316:C649-C654. [PMID: 30840493 DOI: 10.1152/ajpcell.00050.2019] [Citation(s) in RCA: 52] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Myonuclei gained during exercise-induced skeletal muscle hypertrophy may be long-lasting and could facilitate future muscle adaptability after deconditioning, a concept colloquially termed "muscle memory." The evidence for this is limited, mostly due to the lack of a murine exercise-training paradigm that is nonsurgical and reversible. To address this limitation, we developed a novel progressive weighted-wheel-running (PoWeR) model of murine exercise training to test whether myonuclei gained during exercise persist after detraining. We hypothesized that myonuclei acquired during training-induced hypertrophy would remain following loss of muscle mass with detraining. Singly housed female C57BL/6J mice performed 8 wk of PoWeR, while another group performed 8 wk of PoWeR followed by 12 wk of detraining. Age-matched sedentary cage-dwelling mice served as untrained controls. Eight weeks of PoWeR yielded significant plantaris muscle fiber hypertrophy, a shift to a more oxidative phenotype, and greater myonuclear density than untrained mice. After 12 wk of detraining, the plantaris muscle returned to an untrained phenotype with fewer myonuclei. A finding of fewer myonuclei simultaneously with plantaris deconditioning argues against a muscle memory mechanism mediated by elevated myonuclear density in primarily fast-twitch muscle. PoWeR is a novel, practical, and easy-to-deploy approach for eliciting robust hypertrophy in mice, and our findings can inform future research on the mechanisms underlying skeletal muscle adaptive potential and muscle memory.
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Affiliation(s)
- Cory M Dungan
- Department of Rehabilitation Sciences, University of Kentucky , Lexington, Kentucky.,Center for Muscle Biology, University of Kentucky , Lexington, Kentucky
| | - Kevin A Murach
- Department of Rehabilitation Sciences, University of Kentucky , Lexington, Kentucky.,Center for Muscle Biology, University of Kentucky , Lexington, Kentucky
| | - Kaitlyn K Frick
- Center for Muscle Biology, University of Kentucky , Lexington, Kentucky
| | - Savannah R Jones
- Center for Muscle Biology, University of Kentucky , Lexington, Kentucky
| | - Samuel E Crow
- Center for Muscle Biology, University of Kentucky , Lexington, Kentucky
| | - Davis A Englund
- Department of Rehabilitation Sciences, University of Kentucky , Lexington, Kentucky.,Center for Muscle Biology, University of Kentucky , Lexington, Kentucky
| | - Ivan J Vechetti
- Department of Physiology, University of Kentucky , Lexington, Kentucky.,Center for Muscle Biology, University of Kentucky , Lexington, Kentucky
| | - Vandre C Figueiredo
- Department of Rehabilitation Sciences, University of Kentucky , Lexington, Kentucky.,Center for Muscle Biology, University of Kentucky , Lexington, Kentucky
| | - Bryana M Levitan
- Center for Molecular Medicine, University of Kentucky , Lexington, Kentucky
| | - Jonathan Satin
- Department of Physiology, University of Kentucky , Lexington, Kentucky
| | - John J McCarthy
- Department of Physiology, University of Kentucky , Lexington, Kentucky.,Center for Muscle Biology, University of Kentucky , Lexington, Kentucky
| | - Charlotte A Peterson
- Department of Rehabilitation Sciences, University of Kentucky , Lexington, Kentucky.,Center for Muscle Biology, University of Kentucky , Lexington, Kentucky
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13
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Walton RG, Kosmac K, Mula J, Fry CS, Peck BD, Groshong JS, Finlin BS, Zhu B, Kern PA, Peterson CA. Human skeletal muscle macrophages increase following cycle training and are associated with adaptations that may facilitate growth. Sci Rep 2019; 9:969. [PMID: 30700754 PMCID: PMC6353900 DOI: 10.1038/s41598-018-37187-1] [Citation(s) in RCA: 59] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2018] [Accepted: 11/23/2018] [Indexed: 12/26/2022] Open
Abstract
Skeletal muscle macrophages participate in repair and regeneration following injury. However, their role in physiological adaptations to exercise is unexplored. We determined whether endurance exercise training (EET) alters macrophage content and characteristics in response to resistance exercise (RE), and whether macrophages are associated with other exercise adaptations. Subjects provided vastus lateralis biopsies before and after one bout of RE, after 12 weeks of EET (cycling), and after a final bout of RE. M2 macrophages (CD11b+/CD206+) did not increase with RE, but increased in response to EET (P < 0.01). Increases in M2 macrophages were positively correlated with fiber hypertrophy (r = 0.49) and satellite cells (r = 0.47). M2c macrophages (CD206+/CD163+) also increased following EET (P < 0.001), and were associated with fiber hypertrophy (r = 0.64). Gene expression was quantified using NanoString. Following EET, the change in M2 macrophages was positively associated with changes in HGF, IGF1, and extracellular matrix genes. EET decreased expression of IL6 (P < 0.05), C/EBPβ (P < 0.01), and MuRF (P < 0.05), and increased expression of IL-4 (P < 0.01), TNFα (P < 0.01) and the TWEAK receptor FN14 (P < 0.05). The change in FN14 gene expression was inversely associated with changes in C/EBPβ (r = -0.58) and MuRF (r = -0.46) following EET. In cultured human myotubes, siRNA inhibition of FN14 increased expression of C/EBPβ (P < 0.05) and MuRF (P < 0.05). Our data suggest that macrophages contribute to the muscle response to EET, potentially including modulation of TWEAK-FN14 signaling.
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Affiliation(s)
- R Grace Walton
- College of Health Sciences and Center for Muscle Biology, University of Kentucky, Lexington, Kentucky, USA.
| | - Kate Kosmac
- College of Health Sciences and Center for Muscle Biology, University of Kentucky, Lexington, Kentucky, USA
| | - Jyothi Mula
- College of Health Sciences and Center for Muscle Biology, University of Kentucky, Lexington, Kentucky, USA
| | - Christopher S Fry
- Deptartment of Nutrition & Metabolism, School of Health Professions, University of Texas Medical Branch at Galveston, Galveston, Texas, USA
| | - Bailey D Peck
- College of Health Sciences and Center for Muscle Biology, University of Kentucky, Lexington, Kentucky, USA
| | - Jason S Groshong
- Department of Health Professions, University of Central Florida, Orlando, Florida, USA
| | - Brian S Finlin
- Department of Medicine, Division of Endocrinology, and Barnstable Brown Diabetes and Obesity Center, University of Kentucky, Lexington, Kentucky, USA
| | - Beibei Zhu
- Department of Medicine, Division of Endocrinology, and Barnstable Brown Diabetes and Obesity Center, University of Kentucky, Lexington, Kentucky, USA
| | - Philip A Kern
- Department of Medicine, Division of Endocrinology, and Barnstable Brown Diabetes and Obesity Center, University of Kentucky, Lexington, Kentucky, USA
| | - Charlotte A Peterson
- College of Health Sciences and Center for Muscle Biology, University of Kentucky, Lexington, Kentucky, USA
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14
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Murach KA. To hypertrophy and beyond! Myostatin and its association to intermuscular adipose tissue with exercise and aging. Am J Physiol Regul Integr Comp Physiol 2018; 315:R423-R424. [PMID: 29741932 DOI: 10.1152/ajpregu.00122.2018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Affiliation(s)
- Kevin A Murach
- The Center for Muscle Biology, College of Health Sciences, Department of Rehabilitation Sciences, University of Kentucky , Lexington, Kentucky
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15
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Matsubara Y, Furuyama T, Nakayama K, Yoshiya K, Inoue K, Morisaki K, Kume M, Maehara Y. High intramuscular adipose tissue content as a precondition of sarcopenia in patients with aortic aneurysm. Surg Today 2018; 48:1052-1059. [DOI: 10.1007/s00595-018-1697-9] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2018] [Accepted: 06/28/2018] [Indexed: 12/25/2022]
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16
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Joanisse S, Snijders T, Nederveen JP, Parise G. The Impact of Aerobic Exercise on the Muscle Stem Cell Response. Exerc Sport Sci Rev 2018; 46:180-187. [DOI: 10.1249/jes.0000000000000153] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
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17
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Murach KA, Englund DA, Dupont-Versteegden EE, McCarthy JJ, Peterson CA. Myonuclear Domain Flexibility Challenges Rigid Assumptions on Satellite Cell Contribution to Skeletal Muscle Fiber Hypertrophy. Front Physiol 2018; 9:635. [PMID: 29896117 PMCID: PMC5986879 DOI: 10.3389/fphys.2018.00635] [Citation(s) in RCA: 61] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2018] [Accepted: 05/11/2018] [Indexed: 12/29/2022] Open
Abstract
Satellite cell-mediated myonuclear accretion is thought to be required for skeletal muscle fiber hypertrophy, and even drive hypertrophy by preceding growth. Recent studies in humans and rodents provide evidence that challenge this axiom. Specifically, Type 2 muscle fibers reliably demonstrate a substantial capacity to hypertrophy in the absence of myonuclear accretion, challenging the notion of a tightly regulated myonuclear domain (i.e., area that each myonucleus transcriptionally governs). In fact, a “myonuclear domain ceiling”, or upper limit of transcriptional output per nucleus to support hypertrophy, has yet to be identified. Satellite cells respond to muscle damage, and also play an important role in extracellular matrix remodeling during loading-induced hypertrophy. We postulate that robust satellite cell activation and proliferation in response to mechanical loading is largely for these purposes. Future work will aim to elucidate the mechanisms by which Type 2 fibers can hypertrophy without additional myonuclei, the extent to which Type 1 fibers can grow without myonuclear accretion, and whether a true myonuclear domain ceiling exists.
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Affiliation(s)
- Kevin A Murach
- The Center for Muscle Biology, College of Health Sciences, University of Kentucky, Lexington, KY, United States.,Department of Rehabilitation Sciences, College of Health Sciences, University of Kentucky, Lexington, KY, United States
| | - Davis A Englund
- The Center for Muscle Biology, College of Health Sciences, University of Kentucky, Lexington, KY, United States.,Department of Rehabilitation Sciences, College of Health Sciences, University of Kentucky, Lexington, KY, United States
| | - Esther E Dupont-Versteegden
- The Center for Muscle Biology, College of Health Sciences, University of Kentucky, Lexington, KY, United States.,Department of Rehabilitation Sciences, College of Health Sciences, University of Kentucky, Lexington, KY, United States
| | - John J McCarthy
- The Center for Muscle Biology, College of Health Sciences, University of Kentucky, Lexington, KY, United States.,Department of Physiology, College of Medicine, University of Kentucky, Lexington, KY, United States
| | - Charlotte A Peterson
- The Center for Muscle Biology, College of Health Sciences, University of Kentucky, Lexington, KY, United States.,Department of Rehabilitation Sciences, College of Health Sciences, University of Kentucky, Lexington, KY, United States
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18
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Murach KA, Fry CS, Kirby TJ, Jackson JR, Lee JD, White SH, Dupont-Versteegden EE, McCarthy JJ, Peterson CA. Starring or Supporting Role? Satellite Cells and Skeletal Muscle Fiber Size Regulation. Physiology (Bethesda) 2018; 33:26-38. [PMID: 29212890 PMCID: PMC5866409 DOI: 10.1152/physiol.00019.2017] [Citation(s) in RCA: 74] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2017] [Revised: 09/18/2017] [Accepted: 09/18/2017] [Indexed: 12/22/2022] Open
Abstract
Recent loss-of-function studies show that satellite cell depletion does not promote sarcopenia or unloading-induced atrophy, and does not prevent regrowth. Although overload-induced muscle fiber hypertrophy is normally associated with satellite cell-mediated myonuclear accretion, hypertrophic adaptation proceeds in the absence of satellite cells in fully grown adult mice, but not in young growing mice. Emerging evidence also indicates that satellite cells play an important role in remodeling the extracellular matrix during hypertrophy.
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Affiliation(s)
- Kevin A Murach
- The Center for Muscle Biology, University of Kentucky, Lexington, Kentucky
- Department of Rehabilitation Sciences, College of Health Sciences, University of Kentucky, Lexington, Kentucky
| | - Christopher S Fry
- Department of Nutrition and Metabolism, School of Health Professions, University of Texas Medical Branch at Galveston, Galveston, Texas
| | - Tyler J Kirby
- The Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, New York
| | - Janna R Jackson
- The Center for Muscle Biology, University of Kentucky, Lexington, Kentucky
- Department of Rehabilitation Sciences, College of Health Sciences, University of Kentucky, Lexington, Kentucky
| | - Jonah D Lee
- Environment, Health, and Safety, University of Michigan, Ann Arbor, Michigan
| | - Sarah H White
- Department of Animal Science, Texas A&M University, College Station, Texas; and
| | - Esther E Dupont-Versteegden
- The Center for Muscle Biology, University of Kentucky, Lexington, Kentucky
- Department of Rehabilitation Sciences, 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 Rehabilitation Sciences, College of Health Sciences, University of Kentucky, Lexington, Kentucky
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19
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Murach KA, Confides AL, Ho A, Jackson JR, Ghazala LS, Peterson CA, Dupont-Versteegden EE. Depletion of Pax7+ satellite cells does not affect diaphragm adaptations to running in young or aged mice. J Physiol 2017; 595:6299-6311. [PMID: 28736900 DOI: 10.1113/jp274611] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2017] [Accepted: 07/18/2017] [Indexed: 12/14/2022] Open
Abstract
KEY POINTS Satellite cell depletion does not affect diaphragm adaptations to voluntary wheel running in young or aged mice. Satellite cell depletion early in life (4 months of age) has minimal effect on diaphragm phenotype by old age (24 months). Prolonged satellite cell depletion in the diaphragm does not result in excessive extracellular matrix accumulation, in contrast to what has been reported in hind limb muscles. Up-regulation of Pax3 mRNA+ cells after satellite cell depletion in young and aged mice suggests that Pax3+ cells may compensate for a loss of Pax7+ satellite cells in the diaphragm. Future investigations should focus on the role of Pax3+ cells in the diaphragm during adaptation to exercise and ageing. ABSTRACT Satellite cell contribution to unstressed diaphragm is higher compared to hind limb muscles, which is probably attributable to constant activation of this muscle to drive ventilation. Whether satellite cell depletion negatively impacts diaphragm quantitative and qualitative characteristics under stressed conditions in young and aged mice is unknown. We therefore challenged the diaphragm with prolonged running activity in the presence and absence of Pax7+ satellite cells in young and aged mice using an inducible Pax7CreER -R26RDTA model. Mice were vehicle (Veh, satellite cell-replete) or tamoxifen (Tam, satellite cell-depleted) treated at 4 months of age and were then allowed to run voluntarily at 6 months (young) and 22 months (aged). Age-matched, cage-dwelling, Veh- and Tam-treated mice without wheel access served as activity controls. Diaphragm muscles were analysed from young (8 months) and aged (24 months) mice. Satellite cell depletion did not alter diaphragm mean fibre cross-sectional area, fibre type distribution or extracellular matrix content in young or aged mice, regardless of running activity. Resting in vivo diaphragm function was also unaffected by satellite cell depletion. Myonuclear density was maintained in young satellite cell-depleted mice regardless of running, although it was modestly reduced in aged sedentary (-7%) and running (-19%) mice without satellite cells (P < 0.05). Using fluorescence in situ hybridization, we detected higher Pax3 mRNA+ cell density in both young and aged satellite cell-depleted diaphragm muscle (P < 0.05), which may compensate for the loss of Pax7+ satellite cells.
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Affiliation(s)
- Kevin A Murach
- College of Health Sciences, Department of Rehabilitation Sciences, and the Center for Muscle Biology, University of Kentucky, Lexington, KY, USA
| | - Amy L Confides
- College of Health Sciences, Department of Rehabilitation Sciences, and the Center for Muscle Biology, University of Kentucky, Lexington, KY, USA
| | - Angel Ho
- College of Health Sciences, Department of Rehabilitation Sciences, and the Center for Muscle Biology, University of Kentucky, Lexington, KY, USA
| | - Janna R Jackson
- College of Health Sciences, Department of Rehabilitation Sciences, and the Center for Muscle Biology, University of Kentucky, Lexington, KY, USA
| | - Lina S Ghazala
- College of Health Sciences, Department of Rehabilitation Sciences, and the Center for Muscle Biology, University of Kentucky, Lexington, KY, USA
| | - Charlotte A Peterson
- College of Health Sciences, Department of Rehabilitation Sciences, and the Center for Muscle Biology, University of Kentucky, Lexington, KY, USA
| | - Esther E Dupont-Versteegden
- College of Health Sciences, Department of Rehabilitation Sciences, and the Center for Muscle Biology, University of Kentucky, Lexington, KY, USA
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20
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Ceccarelli G, Benedetti L, Arcari ML, Carubbi C, Galli D. Muscle Stem Cell and Physical Activity: What Point is the Debate at? Open Med (Wars) 2017; 12:144-156. [PMID: 28765836 PMCID: PMC5529938 DOI: 10.1515/med-2017-0022] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2016] [Accepted: 04/21/2017] [Indexed: 12/11/2022] Open
Abstract
In the last 15 years, it emerged that the practice of regular physical activity reduces the risks of many diseases (cardiovascular diseases, diabetes, etc.) and it is fundamental in weight control and energy consuming to contrast obesity. Different groups proposed many molecular mechanisms as responsible for the positive effects of physical activity in healthy life. However, many points remain to be clarified. In this mini-review we reported the latest observations on the effects of physical exercise on healthy skeletal and cardiac muscle focusing on muscle stem cells. The last ones represent the fundamental elements for muscle regeneration post injury, but also for healthy muscle homeostasis. Interestingly, in both muscle tissues the morphological consequence of physical activity is a physiological hypertrophy that depends on different phenomena both in differentiated cells and stem cells. The signaling pathways for physical exercise effects present common elements in skeletal and cardiac muscle, like activation of specific transcription factors, proliferative pathways, and cytokines. More recently, post translational (miRNAs) or epigenetic (DNA methylation) modifications have been demonstrated. However, several points remain unresolved thus requiring new research on the effect of exercise on muscle stem cells.
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Affiliation(s)
- Gabriele Ceccarelli
- Department of Public Health, Experimental Medicine and Forensic, University of Pavia, Pavia, Italy.,Center of Health Technologies (CHT), University of Pavia, Pavia, Italy
| | - Laura Benedetti
- Department of Public Health, Experimental Medicine and Forensic, University of Pavia, Pavia, Italy.,Center of Health Technologies (CHT), University of Pavia, Pavia, Italy
| | - Maria Luisa Arcari
- Department of Medicine and Surgery, S.Bi.Bi.T. Unit, University of Parma, Parma, Italy
| | - Cecilia Carubbi
- Department of Medicine and Surgery, S.Bi.Bi.T. Unit, University of Parma, Parma, Italy
| | - Daniela Galli
- Department of Medicine and Surgery, S.Bi.Bi.T. Unit and Sport and Exercise Medicine Center (SEM)., University of Parma c/o Ospedale Maggiore, Via Gramsci, 14, 43126, Tel: +39-0521-036306, , Parma, Italy.,Department of Medicine and Surgery, S.Bi.Bi.T. Unit, University of Parma, Parma, Italy
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21
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Murach KA, White SH, Wen Y, Ho A, Dupont-Versteegden EE, McCarthy JJ, Peterson CA. Differential requirement for satellite cells during overload-induced muscle hypertrophy in growing versus mature mice. Skelet Muscle 2017; 7:14. [PMID: 28693603 PMCID: PMC5504676 DOI: 10.1186/s13395-017-0132-z] [Citation(s) in RCA: 90] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2017] [Accepted: 06/26/2017] [Indexed: 01/30/2023] Open
Abstract
Background Pax7+ satellite cells are required for skeletal muscle fiber growth during post-natal development in mice. Satellite cell-mediated myonuclear accretion also appears to persist into early adulthood. Given the important role of satellite cells during muscle development, we hypothesized that the necessity of satellite cells for adaptation to an imposed hypertrophic stimulus depends on maturational age. Methods Pax7CreER-R26RDTA mice were treated for 5 days with vehicle (satellite cell-replete, SC+) or tamoxifen (satellite cell-depleted, SC-) at 2 months (young) and 4 months (mature) of age. Following a 2-week washout, mice were subjected to sham surgery or 10 day synergist ablation overload of the plantaris (n = 6–9 per group). The surgical approach minimized regeneration, de novo fiber formation, and fiber splitting while promoting muscle fiber growth. Satellite cell density (Pax7+ cells/fiber), embryonic myosin heavy chain expression (eMyHC), and muscle fiber cross sectional area (CSA) were evaluated via immunohistochemistry. Myonuclei (myonuclei/100 mm) were counted on isolated single muscle fibers. Results Tamoxifen treatment depleted satellite cells by ≥90% and prevented myonuclear accretion with overload in young and mature mice (p < 0.05). Satellite cells did not recover in SC- mice after overload. Average muscle fiber CSA increased ~20% in young SC+ (p = 0.07), mature SC+ (p < 0.05), and mature SC- mice (p < 0.05). In contrast, muscle fiber hypertrophy was prevented in young SC- mice. Muscle fiber number increased only in mature mice after overload (p < 0.05), and eMyHC expression was variable, specifically in mature SC+ mice. Conclusions Reliance on satellite cells for overload-induced hypertrophy is dependent on maturational age, and global responses to overload differ in young versus mature mice. Electronic supplementary material The online version of this article (doi:10.1186/s13395-017-0132-z) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Kevin A Murach
- Department of Rehabilitation Sciences, College of Health Sciences, 900 South Limestone, Lexington, KY 40536 USA.,The Center for Muscle Biology, University of Kentucky, 900 South Limestone, Lexington, KY 40536 USA
| | - Sarah H White
- Department of Rehabilitation Sciences, College of Health Sciences, 900 South Limestone, Lexington, KY 40536 USA.,The Center for Muscle Biology, University of Kentucky, 900 South Limestone, Lexington, KY 40536 USA.,Department of Animal Science, Texas A&M University, College Station, TX 77843 USA
| | - Yuan Wen
- Department of Physiology, College of Medicine, 800 Rose Street, Lexington, KY 40536 USA.,The Center for Muscle Biology, University of Kentucky, 900 South Limestone, Lexington, KY 40536 USA
| | - Angel Ho
- Department of Rehabilitation Sciences, College of Health Sciences, 900 South Limestone, Lexington, KY 40536 USA.,The Center for Muscle Biology, University of Kentucky, 900 South Limestone, Lexington, KY 40536 USA
| | - Esther E Dupont-Versteegden
- Department of Rehabilitation Sciences, College of Health Sciences, 900 South Limestone, Lexington, KY 40536 USA.,The Center for Muscle Biology, University of Kentucky, 900 South Limestone, Lexington, KY 40536 USA
| | - John J McCarthy
- Department of Physiology, College of Medicine, 800 Rose Street, Lexington, KY 40536 USA.,The Center for Muscle Biology, University of Kentucky, 900 South Limestone, Lexington, KY 40536 USA
| | - Charlotte A Peterson
- Department of Rehabilitation Sciences, College of Health Sciences, 900 South Limestone, Lexington, KY 40536 USA.,The Center for Muscle Biology, University of Kentucky, 900 South Limestone, Lexington, KY 40536 USA
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22
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McKenzie AI, D'Lugos AC, Saunders MJ, Gworek KD, Luden ND. Fiber Type-Specific Satellite Cell Content in Cyclists Following Heavy Training with Carbohydrate and Carbohydrate-Protein Supplementation. Front Physiol 2016; 7:550. [PMID: 27899900 PMCID: PMC5110549 DOI: 10.3389/fphys.2016.00550] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2016] [Accepted: 11/01/2016] [Indexed: 12/25/2022] Open
Abstract
The central purpose of this study was to evaluate the fiber type-specific satellite cell and myonuclear responses of endurance-trained cyclists to a block of intensified training, when supplementing with carbohydrate (CHO) vs. carbohydrate-protein (PRO). In a crossover design, endurance-trained cyclists (n = 8) performed two consecutive training periods, once supplementing with CHO (de facto “control” condition) and the other with PRO. Each training period consisted of 10 days of intensified cycle training (ICT–120% increase in average training duration) followed by 10 days of recovery (RVT–reduced volume training; 33% volume reduction vs. normal training). Skeletal muscle biopsies were obtained from the vastus lateralis before and after ICT and again following RVT. Immunofluorescent microscopy was used to quantify SCs (Pax7+), myonuclei (DAPI+), and myosin heavy chain I (MyHC I). Data are expressed as percent change ± 90% confidence limits. The 10-day block of ICTCHO increased MyHC I SC content (35 ± 28%) and myonuclear density (16 ± 6%), which remained elevated following RVTCHO (SC = 69 ± 50% vs. PRE; Nuclei = 17 ± 15% vs. PRE). MyHC II SC and myonuclei were not different following ICTCHO, but were higher following RVTCHO (SC = +33 ± 31% vs. PRE; Nuclei = 15 ± 14% vs. PRE), indicating a delayed response compared to MyHC I fibers. The MyHC I SC pool increased following ICTPRO (37 ± 37%), but without a concomitant increase in myonuclei. There were no changes in MyHC II SC or myonuclei following ICTPRO. Collectively, these trained endurance cyclists possessed a relatively large pool of SCs that facilitated rapid (MyHC I) and delayed (MyHC II) satellite cell proliferation and myonuclear accretion under carbohydrate conditions. The current findings strengthen the growing body of evidence demonstrating alterations in satellite cell number in the absence of hypertrophy. Satellite cell pool expansion is typically viewed as an advantageous response to exercise. However, when coupled with our previous report that PRO possibly enhanced whole muscle recovery and increased MyHC I and II fiber size, the limited satellite cell/myonuclear response observed with carbohydrate-protein seem to indicate that protein supplementation may have minimized the necessity for satellite cell involvement, thereby suggesting that protein may benefit skeletal muscle during periods of heavy training.
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Affiliation(s)
- Alec I McKenzie
- Human Performance Laboratory, James Madison University Harrisonburg, VA, USA
| | - Andrew C D'Lugos
- Human Performance Laboratory, James Madison University Harrisonburg, VA, USA
| | - Michael J Saunders
- Human Performance Laboratory, James Madison University Harrisonburg, VA, USA
| | - Keith D Gworek
- Human Performance Laboratory, James Madison University Harrisonburg, VA, USA
| | - Nicholas D Luden
- Human Performance Laboratory, James Madison University Harrisonburg, VA, USA
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23
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Murach KA, Walton RG, Fry CS, Michaelis SL, Groshong JS, Finlin BS, Kern PA, Peterson CA. Cycle training modulates satellite cell and transcriptional responses to a bout of resistance exercise. Physiol Rep 2016; 4:e12973. [PMID: 27650251 PMCID: PMC5037921 DOI: 10.14814/phy2.12973] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2016] [Accepted: 08/23/2016] [Indexed: 12/17/2022] Open
Abstract
This investigation evaluated whether moderate-intensity cycle ergometer training affects satellite cell and molecular responses to acute maximal concentric/eccentric resistance exercise in middle-aged women. Baseline and 72 h postresistance exercise vastus lateralis biopsies were obtained from seven healthy middle-aged women (56 ± 5 years, BMI 26 ± 1, VO2max 27 ± 4) before and after 12 weeks of cycle training. Myosin heavy chain (MyHC) I- and II-associated satellite cell density and cross-sectional area was determined via immunohistochemistry. Expression of 93 genes representative of the muscle-remodeling environment was also measured via NanoString. Overall fiber size increased ~20% with cycle training (P = 0.052). MyHC I satellite cell density increased 29% in response to acute resistance exercise before endurance training and 50% with endurance training (P < 0.05). Following endurance training, MyHC I satellite cell density decreased by 13% in response to acute resistance exercise (acute resistance × training interaction, P < 0.05). Genes with an interaction effect tracked with satellite cell behavior, increasing in the untrained state and decreasing in the endurance trained state in response to resistance exercise. Similar satellite cell and gene expression response patterns indicate coordinated regulation of the muscle environment to promote adaptation. Moderate-intensity endurance cycle training modulates the response to acute resistance exercise, potentially conditioning the muscle for more intense concentric/eccentric activity. These results suggest that cycle training is an effective endurance exercise modality for promoting growth in middle-aged women, who are susceptible to muscle mass loss with progressing age.
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Affiliation(s)
- Kevin A Murach
- Department of Rehabilitation Sciences, Center for Muscle Biology, College of Health Sciences, University of Kentucky, Lexington, Kentucky
| | - R Grace Walton
- Department of Rehabilitation Sciences, Center for Muscle Biology, College of Health Sciences, University of Kentucky, Lexington, Kentucky
| | - Christopher S Fry
- Department of Nutrition and Metabolism, University of Texas Medical Branch, Galveston, Texas
| | - Sami L Michaelis
- Department of Rehabilitation Sciences, Center for Muscle Biology, College of Health Sciences, University of Kentucky, Lexington, Kentucky
| | - Jason S Groshong
- Department of Rehabilitation Sciences, Center for Muscle Biology, College of Health Sciences, University of Kentucky, Lexington, Kentucky
| | - Brian S Finlin
- Division of Endocrinology, and Barnstable Brown Diabetes and Obesity Center, Department of Medicine, University of Kentucky, Lexington, Kentucky
| | - Philip A Kern
- Division of Endocrinology, and Barnstable Brown Diabetes and Obesity Center, Department of Medicine, University of Kentucky, Lexington, Kentucky
| | - Charlotte A Peterson
- Department of Rehabilitation Sciences, Center for Muscle Biology, College of Health Sciences, University of Kentucky, Lexington, Kentucky
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