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Traversa C. Skeletal Muscle Memory: An Update From the Antidoping Perspective. Drug Test Anal 2024. [PMID: 39317641 DOI: 10.1002/dta.3804] [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: 04/12/2024] [Revised: 08/30/2024] [Accepted: 09/02/2024] [Indexed: 09/26/2024]
Abstract
This narrative review explores the concept of muscle memory, focusing on the physiological and biochemical mechanisms underlying information retention in skeletal muscle tissue as it relates to antidoping. The discussion encompasses the role of satellite cells (SCs) in myonuclei recruitment, resulting in increased myonuclear density and heightened muscle protein turnover. The myonuclear domain theory suggests that myonuclei acquired during hypertrophy may persist, contributing to enhanced muscle protein synthesis (MPS) and potential benefits of muscle memory. The impact of sustained training, protein intake, and resistance exercise on muscle memory, especially in elite athletes, is considered. The review also delves into the influence of anabolic androgenic steroids (AAS) on muscle tissue, highlighting their role in elevating the performance threshold and supporting recovery during intense training through increased muscle protein turnover rates. Additionally, genetic and epigenetic modifications, such as DNA methylation, are explored as potential contributors to muscle memory. The complex interplay of continuous training, AAS use, and genetic factors offers avenues for further research, especially in the context of antidoping efforts. The understanding of muscle memory has implications for maintaining performance gains and addressing ethical challenges in sports.
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Affiliation(s)
- Claire Traversa
- World Anti-Doping Agency (WADA), Montreal, Quebec, Canada
- Department of Kinesiology and Physical Education, McGill University, Montreal, Quebec, Canada
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2
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Handelsman DJ. Toward a Robust Definition of Sport Sex. Endocr Rev 2024; 45:709-736. [PMID: 38578952 DOI: 10.1210/endrev/bnae013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/23/2023] [Revised: 01/17/2024] [Accepted: 03/26/2024] [Indexed: 04/07/2024]
Abstract
Elite individual sports in which success depends on power, speed, or endurance are conventionally divided into male and female events using traditional binary definitions of sex. Male puberty creates durable physical advantages due to the 20- to 30-fold increase in circulating testosterone producing a sustained uplift in men's muscle, bone, hemoglobin, and cardiorespiratory function resulting from male puberty and sustained during men's lives. These male physical advantages provide strong justification for a separate protected category of female events allowing women to achieve the fame and fortune from success they would be denied if competing against men. Recent wider social acceptance of transgender individuals, together with the less recognized involvement of intersex individuals, challenge and threaten to defeat the sex classifications for elite individual female events. This can create unfair advantages if seeking inclusion into elite female events of unmodified male-bodied athletes with female gender identity who have gained the physical advantages of male puberty. Based on reproductive physiology, this paper proposes a working definition of sport sex based primarily on an individual's experience of male puberty and can be applied to transgender and various XY intersex conditions. Consistent with the multidimensionality of biological sex (chromosomal, genetic, hormonal, anatomical sex), this definition may be viewed as a multistrand cable whose overall strength survives when any single strand weakens or fails, rather than as a unidimensional chain whose strength is only as good as its weakest link.
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Affiliation(s)
- David J Handelsman
- Andrology Department, ANZAC Research Institute, University of Sydney, Concord Hospital, Syndey, NSW 2139, Australia
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3
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Nielsen JL, Rasmussen JJ, Frandsen MN, Fredberg J, Brandt-Jacobsen NH, Aagaard P, Kistorp C. Higher Myonuclei Density in Muscle Fibers Persists Among Former Users of Anabolic Androgenic Steroids. J Clin Endocrinol Metab 2023; 109:e266-e273. [PMID: 37466198 DOI: 10.1210/clinem/dgad432] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/04/2023] [Revised: 07/13/2023] [Accepted: 07/17/2023] [Indexed: 07/20/2023]
Abstract
CONTEXT No information exists on the long-lasting effects of supraphysiological anabolic androgenic steroids (AASs) usage on the myocellular properties of human skeletal muscle in previous AAS users. OBJECTIVE We hypothesized that former AAS users would demonstrate smaller myonuclei domains (ie, higher myonuclei density) than matched controls. METHODS A community-based cross-sectional study in men aged 18-50 years engaged in recreational strength training. Muscle biopsies were obtained from the m. vastus lateralis. Immunofluorescence analyses were performed to quantify myonuclei density and myofiber size. RESULTS Twenty-five males were included: 8 current and 7 previous AAS users and 10 controls. Median (25th-75th percentiles) accumulated duration of AAS use was 174 (101-206) and 140 (24-260) weeks in current and former AAS users, respectively (P = .482). Geometric mean (95% CI) elapsed duration since AAS cessation was 4.0 (1.2; 12.7) years among former AAS users. Type II muscle fibers in former AAS users displayed higher myonuclei density and DNA to cytoplasm ratio than controls, corresponding to smaller myonuclei domains (P = .013). Longer accumulated AAS use (weeks, log2) was associated with smaller myonuclei domains in previous AAS users: beta-coefficient (95% CI) -94 (-169; -18), P = .024. Type I fibers in current AAS users exhibited a higher amount of satellite cells per myofiber (P = .031) than controls. CONCLUSION Muscle fibers in former AAS users demonstrated persistently higher myonuclei density and DNA to cytoplasm ratio 4 years after AAS cessation suggestive of enhanced retraining capacity.
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Affiliation(s)
- Jakob Lindberg Nielsen
- Department of Sports Science and Clinical Biomechanics, University of Southern Denmark, Odense DK-5230, Denmark
| | - Jon Jarløv Rasmussen
- Department of Medical Endocrinology, Copenhagen University Hospital, Rigshospitalet, Copenhagen DK-2200, Denmark
| | - Mikkel Nicklas Frandsen
- Department of Medical Endocrinology, Copenhagen University Hospital, Rigshospitalet, Copenhagen DK-2200, Denmark
| | - Jeppe Fredberg
- Department of Medical Endocrinology, Copenhagen University Hospital, Rigshospitalet, Copenhagen DK-2200, Denmark
| | - Niels Høegh Brandt-Jacobsen
- Department of Medical Endocrinology, Copenhagen University Hospital, Rigshospitalet, Copenhagen DK-2200, Denmark
| | - Per Aagaard
- Department of Sports Science and Clinical Biomechanics, University of Southern Denmark, Odense DK-5230, Denmark
| | - Caroline Kistorp
- Department of Medical Endocrinology, Copenhagen University Hospital, Rigshospitalet, Copenhagen DK-2200, Denmark
- Department of Clinical Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen DK-2200, Denmark
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4
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Wilson MT, Hunter AM, Fairweather M, Kerr S, Hamilton DL, Macgregor LJ. Enhanced skeletal muscle contractile function and corticospinal excitability precede strength and architectural adaptations during lower-limb resistance training. Eur J Appl Physiol 2023; 123:1911-1928. [PMID: 37185932 PMCID: PMC10460716 DOI: 10.1007/s00421-023-05201-8] [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: 10/28/2022] [Accepted: 04/06/2023] [Indexed: 05/17/2023]
Abstract
PURPOSE Evolving investigative techniques are providing greater understanding about the early neuromuscular responses to resistance training among novice exercisers. The aim of this study was to investigate the time-course of changes in muscle contractile mechanics, architecture, neuromuscular, and strength adaptation during the first 6-weeks of lower-limb resistance training. METHODS Forty participants: 22 intervention (10 males/12 females; 173.48 ± 5.20 cm; 74.01 ± 13.13 kg) completed 6-week resistance training, and 18 control (10 males/8 females; 175.52 ± 7.64 cm; 70.92 ± 12.73 kg) performed no resistance training and maintained their habitual activity. Radial muscle displacement (Dm) assessed via tensiomyography, knee extension maximal voluntary contraction (MVC), voluntary activation (VA), corticospinal excitability and inhibition via transcranial magnetic stimulation, motor unit (MU) firing rate, and muscle thickness and pennation angle via ultrasonography were assessed before and after 2, 4, and 6-weeks of dynamic lower-limb resistance training or control. RESULTS After 2-weeks training, Dm reduced by 19-25% in the intervention group; this was before any changes in neural or morphological measures. After 4-weeks training, MVC increased by 15% along with corticospinal excitability by 16%; however, there was no change in VA, corticospinal inhibition, or MU firing rate. After 6-weeks training there was further MVC increase by 6% along with muscle thickness by 13-16% and pennation angle by 13-14%. CONCLUSION Enhanced contractile properties and corticospinal excitability occurred before any muscle architecture, neural, and strength adaptation. Later increases in muscular strength can be accounted for by architectural adaptation.
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Affiliation(s)
- Matthew T Wilson
- Physiology, Exercise, and Nutrition Research Group, Faculty of Health Sciences and Sport, University of Stirling, Stirling, UK
| | - Angus M Hunter
- Physiology, Exercise, and Nutrition Research Group, Faculty of Health Sciences and Sport, University of Stirling, Stirling, UK.
- Department of Sports Sciences, School of Science and Technology, Nottingham Trent University, Nottingham, NG11 8NS, UK.
| | | | - Stewart Kerr
- Life Fit Wellness, Healthcare & Exercise Centre, Falkirk, Scotland, UK
| | - D Lee Hamilton
- Faculty of Health, School of Exercise and Nutrition Sciences, Institute for Physical Activity and Nutrition (IPAN), Deakin University, Geelong, Australia
| | - Lewis J Macgregor
- Physiology, Exercise, and Nutrition Research Group, Faculty of Health Sciences and Sport, University of Stirling, Stirling, UK
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5
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Liao Z, Lan H, Jian X, Huang J, Wang H, Hu J, Liao H. Myofiber directs macrophages IL-10-Vav1-Rac1 efferocytosis pathway in inflamed muscle following CTX myoinjury by activating the intrinsic TGF-β signaling. Cell Commun Signal 2023; 21:168. [PMID: 37403092 DOI: 10.1186/s12964-023-01163-8] [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: 02/23/2023] [Accepted: 05/10/2023] [Indexed: 07/06/2023] Open
Abstract
BACKGROUND To explore the role of skeletal muscle specific TGF-β signaling on macrophages efferocytosis in inflamed muscle caused by Cardiotoxin (CTX) injection. METHODS CTX myoinjury was manipulated in TGF-βr2flox/flox (control) mice or transgenic mice with TGF-β receptor 2 (TGF-βr2) being specifically deleted in skeletal muscle (SM TGF-βr2-/-). Gene levels of TGF-β signal molecules, special inflammatory mediators in damaged muscle or in cultured and differentiated myogenic precursor cells (MPC-myotubes) were monitored by transcriptome microarray or qRT-PCR. TGF-β pathway molecules, myokines and embryonic myosin heavy chain in regenerating myofibers, the phenotype and efferocytosis of macrophages were evaluated by immunofluorescence, immunoblotting, Luminex, or FACS analysis. In vitro apoptotic cells were prepared by UV-irradiation. RESULTS In control mice, TGF-β-Smad2/3 signaling were significantly up-regulated in regenerating centronuclear myofibers after CTX-myoinjury. More severe muscle inflammation was caused by the deficiency of muscle TGF-β signaling, with the increased number of M1, but the decreased number of M2 macrophages. Notably, the deficiency of TGF-β signaling in myofibers dramatically affected on the ability of macrophages to conduct efferocytosis, marked by the decreased number of Annexin-V-F4/80+Tunel+ macrophages in inflamed muscle, and the impaired uptake of macrophages to PKH67+ apoptotic cells transferred into damaged muscle. Further, our study suggested that, the intrinsic TGF-β signaling directed IL-10-Vav1-Rac1 efferocytosis signaling in muscle macrophages. CONCLUSIONS Our data demonstrate that muscle inflammation can be suppressed potentially by activating the intrinsic TGF-β signaling in myofibers to promote IL-10 dependent-macrophages efferocytosis. Video Abstract.
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Affiliation(s)
- Zhaohong Liao
- Guangdong Provincial Key Laboratory of Construction and Detection in Tissue Engineering; Department of Anatomy, School of Basic Medical Sciences, Southern Medical University, Guangzhou, 510515, China
- Department of Laboratory Medicine, School of Medicine, Foshan University, Foshan, 528000, China
| | - Haiqiang Lan
- Guangdong Provincial Key Laboratory of Construction and Detection in Tissue Engineering; Department of Anatomy, School of Basic Medical Sciences, Southern Medical University, Guangzhou, 510515, China
| | - Xiaoting Jian
- Guangdong Provincial Key Laboratory of Construction and Detection in Tissue Engineering; Department of Anatomy, School of Basic Medical Sciences, Southern Medical University, Guangzhou, 510515, China
| | - Jingwen Huang
- Guangdong Provincial Key Laboratory of Construction and Detection in Tissue Engineering; Department of Anatomy, School of Basic Medical Sciences, Southern Medical University, Guangzhou, 510515, China
| | - Han Wang
- Guangdong Provincial Key Laboratory of Construction and Detection in Tissue Engineering; Department of Anatomy, School of Basic Medical Sciences, Southern Medical University, Guangzhou, 510515, China
| | - Jijie Hu
- Department of Orthopedics and Traumatology, Nanfang Hospital, Southern Medical University, Guangzhou, 510515, China.
| | - Hua Liao
- Guangdong Provincial Key Laboratory of Construction and Detection in Tissue Engineering; Department of Anatomy, School of Basic Medical Sciences, Southern Medical University, Guangzhou, 510515, China.
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6
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Bagley JR, Denes LT, McCarthy JJ, Wang ET, Murach KA. The myonuclear domain in adult skeletal muscle fibres: past, present and future. J Physiol 2023; 601:723-741. [PMID: 36629254 PMCID: PMC9931674 DOI: 10.1113/jp283658] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2022] [Accepted: 01/06/2023] [Indexed: 01/12/2023] Open
Abstract
Most cells in the body are mononuclear whereas skeletal muscle fibres are uniquely multinuclear. The nuclei of muscle fibres (myonuclei) are usually situated peripherally which complicates the equitable distribution of gene products. Myonuclear abundance can also change under conditions such as hypertrophy and atrophy. Specialised zones in muscle fibres have different functions and thus distinct synthetic demands from myonuclei. The complex structure and regulatory requirements of multinuclear muscle cells understandably led to the hypothesis that myonuclei govern defined 'domains' to maintain homeostasis and facilitate adaptation. The purpose of this review is to provide historical context for the myonuclear domain and evaluate its veracity with respect to mRNA and protein distribution resulting from myonuclear transcription. We synthesise insights from past and current in vitro and in vivo genetically modified models for studying the myonuclear domain under dynamic conditions. We also cover the most contemporary knowledge on mRNA and protein transport in muscle cells. Insights from emerging technologies such as single myonuclear RNA-sequencing further inform our discussion of the myonuclear domain. We broadly conclude: (1) the myonuclear domain can be flexible during muscle fibre growth and atrophy, (2) the mechanisms and role of myonuclear loss and motility deserve further consideration, (3) mRNA in muscle is actively transported via microtubules and locally restricted, but proteins may travel far from a myonucleus of origin and (4) myonuclear transcriptional specialisation extends beyond the classic neuromuscular and myotendinous populations. A deeper understanding of the myonuclear domain in muscle may promote effective therapies for ageing and disease.
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Affiliation(s)
- James R. Bagley
- Muscle Physiology Laboratory, Department of Kinesiology, San Francisco State University, San Francisco, California
| | | | - John J. McCarthy
- The Center for Muscle Biology, University of Kentucky, Lexington, Kentucky
- Department of Physiology, College of Medicine, University of Kentucky
| | - Eric T. Wang
- Department of Molecular Genetics and Microbiology, Center for NeuroGenetics, University of Florida, Gainesville, Florida
- Myology Institute, University of Florida
- Genetics Institute, University of Florida
| | - Kevin A. Murach
- Exercise Science Research Center, Department of Health, Human Performance, and Recreation, University of Arkansas, Fayetteville, Arkansas
- Cell and Molecular Biology Graduate Program, University of Arkansas
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7
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Eftestøl E, Ochi E, Juvkam IS, Hansson KA, Gundersen K. A juvenile climbing exercise establishes a muscle memory boosting the effects of exercise in adult rats. Acta Physiol (Oxf) 2022; 236:e13879. [PMID: 36017589 DOI: 10.1111/apha.13879] [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: 09/21/2021] [Revised: 08/19/2022] [Accepted: 08/23/2022] [Indexed: 01/29/2023]
Abstract
AIM Investigate whether juvenile exercise could induce a long-term muscle memory, boosting the effects of exercise in adults. METHODS We devised a 5-week climbing exercise scheme with food reward administered to male juvenile rats (post-natal week 4-9). Subsequently, the animals were subjected to 10 weeks of detraining (week 9-19) without climbing and finally retraining during week 19-21. RESULTS The juvenile exercise increased fiber cross-sectional area (fCSA) by 21% (p = 0.0035), boosted nuclear accretion by 13% (p = 0.057), and reduced intraperitoneal fat content by 28% (p = 0.007) and body weight by 9% (p = 0.001). During detraining, the fCSA became similar in the animals that had been climbing compared to naive controls, but the elevated number of myonuclei induced by the climbing were maintained (15%, p = 0.033). When the naive rats were subjected to 2 weeks of adult exercise there was little effect on fCSA, while the previously trained rats displayed an increase of 19% (p = 0.0007). Similarly, when the rats were subjected to unilateral surgical overload in lieu of the adult climbing exercise, the increase in fCSA was 20% (p = 0.0039) in the climbing group, while there was no significant increase in naive rats when comparing to the contralateral leg. CONCLUSION This demonstrates that juvenile exercise can establish a muscle memory boosting the effects of adult exercise. The juvenile climbing exercise with food reward also led to leaner animals with lower body weight. These differences were to some extent maintained throughout the adult detraining period in spite of all animals being fed ad libitum, indicating a form of body weight memory.
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Affiliation(s)
- Einar Eftestøl
- Department of Biosciences, University of Oslo, Oslo, Norway
| | - Eisuke Ochi
- Department of Biosciences, University of Oslo, Oslo, Norway.,Faculty of Bioscience and Applied Chemistry, Hosei University, Tokyo, Japan
| | - Inga S Juvkam
- Department of Biosciences, University of Oslo, Oslo, Norway
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8
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Rahmati M, McCarthy JJ, Malakoutinia F. Myonuclear permanence in skeletal muscle memory: a systematic review and meta-analysis of human and animal studies. J Cachexia Sarcopenia Muscle 2022; 13:2276-2297. [PMID: 35961635 PMCID: PMC9530508 DOI: 10.1002/jcsm.13043] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/17/2022] [Revised: 05/24/2022] [Accepted: 06/13/2022] [Indexed: 12/09/2022] Open
Abstract
One aspect of skeletal muscle memory is the ability of a previously trained muscle to hypertrophy more rapidly following a period of detraining. Although the molecular basis of muscle memory remains to be fully elucidated, one potential mechanism thought to mediate muscle memory is the permanent retention of myonuclei acquired during the initial phase of hypertrophic growth. However, myonuclear permanence is debated and would benefit from a meta-analysis to clarify the current state of the field for this important aspect of skeletal muscle plasticity. The objective of this study was to perform a meta-analysis to assess the permanence of myonuclei associated with changes in physical activity and ageing. When available, the abundance of satellite cells (SCs) was also considered given their potential influence on changes in myonuclear abundance. One hundred forty-seven peer-reviewed articles were identified for inclusion across five separate meta-analyses; (1-2) human and rodent studies assessed muscle response to hypertrophy; (3-4) human and rodent studies assessed muscle response to atrophy; and (5) human studies assessed muscle response with ageing. Skeletal muscle hypertrophy was associated with higher myonuclear content that was retained in rodents, but not humans, with atrophy (SMD = -0.60, 95% CI -1.71 to 0.51, P = 0.29, and MD = 83.46, 95% CI -649.41 to 816.32, P = 0.82; respectively). Myonuclear and SC content were both lower following atrophy in humans (MD = -11, 95% CI -0.19 to -0.03, P = 0.005, and SMD = -0.49, 95% CI -0.77 to -0.22, P = 0.0005; respectively), although the response in rodents was affected by the type of muscle under consideration and the mode of atrophy. Whereas rodent myonuclei were found to be more permanent regardless of the mode of atrophy, atrophy of ≥30% was associated with a reduction in myonuclear content (SMD = -1.02, 95% CI -1.53 to -0.51, P = 0.0001). In humans, sarcopenia was accompanied by a lower myonuclear and SC content (MD = 0.47, 95% CI 0.09 to 0.85, P = 0.02, and SMD = 0.78, 95% CI 0.37-1.19, P = 0.0002; respectively). The major finding from the present meta-analysis is that myonuclei are not permanent but are lost during periods of atrophy and with ageing. These findings do not support the concept of skeletal muscle memory based on the permanence of myonuclei and suggest other mechanisms, such as epigenetics, may have a more important role in mediating this aspect of skeletal muscle plasticity.
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Affiliation(s)
- Masoud Rahmati
- Department of Physical Education and Sport Sciences, Faculty of Literature and Human SciencesLorestan UniversityKhorramabadIran
| | - John J. McCarthy
- Department of PhysiologyUniversity of KentuckyLexingtonKYUSA
- Center for Muscle BiologyUniversity of KentuckyLexingtonKYUSA
| | - Fatemeh Malakoutinia
- Department of Physical Education and Sport Sciences, Faculty of Literature and Human SciencesLorestan UniversityKhorramabadIran
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9
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Kirby TJ, Dupont-Versteegden EE. Cross Talk rebuttal: Kirby and Dupont-Versteegden. J Physiol 2022; 600:2085-2086. [PMID: 35388906 DOI: 10.1113/jp283000] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2022] [Accepted: 03/07/2022] [Indexed: 01/30/2023] Open
Affiliation(s)
- Tyler J Kirby
- Amsterdam UMC, VUmc location, Amsterdam, Netherlands
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10
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Kirby TJ, Dupont-Versteegden EE. Cross Talk proposal: Myonuclei are lost with ageing and atrophy. J Physiol 2022; 600:2077-2080. [PMID: 35388910 PMCID: PMC9197225 DOI: 10.1113/jp282380] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Affiliation(s)
- Tyler J Kirby
- Department of Physiology, Amsterdam Cardiovascular Sciences, Amsterdam Movement Sciences, Amsterdam UMC, Amsterdam, Netherlands
| | - Esther E Dupont-Versteegden
- Department of Physical Therapy and Center for Muscle Biology, College of Health Sciences, University of Kentucky, Lexington, KY, USA
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11
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Schwartz LM, Gundersen K. Cross Talk opposing view: Myonuclei do not undergo apoptosis during skeletal muscle atrophy. J Physiol 2022; 600:2081-2084. [PMID: 35388909 DOI: 10.1113/jp282381] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Affiliation(s)
- Lawrence M Schwartz
- Department of Biology, Morrill Science Center, University of Massachusetts, Amherst, MA, USA
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12
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Age-related structural changes show that loss of fibers is not a significant contributor to muscle atrophy in old mice. Exp Gerontol 2021; 156:111618. [PMID: 34737004 DOI: 10.1016/j.exger.2021.111618] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2021] [Revised: 10/10/2021] [Accepted: 10/29/2021] [Indexed: 12/25/2022]
Abstract
Age-related loss of skeletal muscle mass is widely considered a consequence of both fiber atrophy and fiber death. Evidence for fiber death derives largely from an age-related reduction in fiber numbers in muscle cross-sections, however it is unclear how age-related alterations in muscle morphology affect accuracy of such counts. To explore this we performed an examination of muscle and tendon length, muscle mass and girth, and pennation angle, in addition to histological section fiber counts of parallel-fibered (sternomastoid), fusiform (biceps brachii), and pennate (tibialis anterior, extensor digitorum longus, soleus) muscles from 31 mice aged 6-32 months. Age-related decline in mass and girth occurred in soleus (p = 0.026; p = 0.040), tibialis anterior (p = 0.004; p = 0.039), and extensor digitorum longus (p = 0.040; p = 0.022) muscles, for which location of maximal girth also changed. Tendon length and pennation angle remained consistent across the lifespan in all except soleus which showed elongation of both proximal and distal tendons coupled with alterations in pennation angle. Age-related decreases in fiber number were observed in transversely sectioned soleus and extensor digitorum longus muscles however when age-related changes in morphology were accounted for via oblique sectioning the age-related decrease in fiber number was eliminated. Findings show loss of fibers is not a significant contributor to age-related muscle wasting in mice, and that age-related changes in connective tissue selectively impact muscle structure. Fiber shortening is a likely contributor to loss of mass and change in function in muscles of old mice.
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13
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Horwath O, Envall H, Röja J, Emanuelsson EB, Sanz G, Ekblom B, Apró W, Moberg M. Variability in vastus lateralis fiber type distribution, fiber size, and myonuclear content along and between the legs. J Appl Physiol (1985) 2021; 131:158-173. [PMID: 34013752 DOI: 10.1152/japplphysiol.00053.2021] [Citation(s) in RCA: 35] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Human skeletal muscle characteristics such as fiber type composition, fiber size, and myonuclear content are widely studied in clinical and sports-related contexts. Being aware of the methodological and biological variability of the characteristics is a critical aspect in study design and outcome interpretation, but comprehensive data on the variability of morphological features in human skeletal muscle are currently limited. Accordingly, in the present study, m. vastus lateralis biopsies (10 per subject) from young and healthy individuals, collected in a systematic manner, were analyzed for various characteristics using immunohistochemistry (n = 7) and SDS-PAGE (n = 25). None of the analyzed parameters, fiber type % (FT%), type I and II fiber cross-sectional area (fCSA), percentage fiber type area (fCSA%), myosin heavy chain composition (MyHC%), type IIX content, myonuclear content, or myonuclear domain, varied in a systematic manner longitudinally along the muscle or between the two legs. The average within-subject coefficient of variation for FT%, fCSA, fCSA%, and MyHC% ranged between 13% and 18% but was only 5% for fiber-specific myonuclear content, which reduced the variability for myonuclear domain size to 11%-12%. Pure type IIX fibers and type IIX MyHC were randomly distributed and present in <24% of the analyzed samples, with the average content being 0.1% and 1.1%, respectively. In conclusion, leg or longitudinal orientation does not seem to be an important aspect to consider when investigating human vastus lateralis characteristics. However, single muscle biopsies should preferably not be used when studying fiber type- and fiber size-related aspects, given the notable sample-to-sample variability.NEW & NOTEWORTHY This study provides a comprehensive analysis of the variability of key human skeletal muscle fiber characteristics in multiple sites along and between the m. vastus lateralis of healthy and active individuals. We found a notable but nonsystematic variability in fiber type and size, whereas myonuclear content was distinctively less variable, and the prevalence of type IIX fibers was random and very low. These data are important to consider when designing and interpreting studies including m. vastus lateralis biopsies.
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Affiliation(s)
- Oscar Horwath
- Department of Physiology, Nutrition and Biomechanics, Åstrand Laboratory, Swedish School of Sport and Health Sciences, Stockholm, Sweden
| | - Helena Envall
- Department of Physiology, Nutrition and Biomechanics, Åstrand Laboratory, Swedish School of Sport and Health Sciences, Stockholm, Sweden
| | - Julia Röja
- Department of Physiology, Nutrition and Biomechanics, Åstrand Laboratory, Swedish School of Sport and Health Sciences, Stockholm, Sweden
| | - Eric B Emanuelsson
- Department of Physiology and Pharmacology, Karolinska Institute, Stockholm, Sweden
| | - Gema Sanz
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institute, Stockholm, Sweden.,Gnomics, Murcia, Spain
| | - Björn Ekblom
- Department of Physiology, Nutrition and Biomechanics, Åstrand Laboratory, Swedish School of Sport and Health Sciences, Stockholm, Sweden
| | - William Apró
- Department of Physiology, Nutrition and Biomechanics, Åstrand Laboratory, Swedish School of Sport and Health Sciences, Stockholm, Sweden.,Department of Clinical Science, Intervention and Technology, Karolinska Institute, Stockholm, Sweden
| | - Marcus Moberg
- Department of Physiology, Nutrition and Biomechanics, Åstrand Laboratory, Swedish School of Sport and Health Sciences, Stockholm, Sweden.,Department of Physiology and Pharmacology, Karolinska Institute, Stockholm, Sweden
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14
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Nakanishi R, Tanaka M, Maeshige N, Kondo H, Roy RR, Fujino H. Nucleoprotein-enriched diet enhances protein synthesis pathway and satellite cell activation via ERK1/2 phosphorylation in unloaded rat muscles. Exp Physiol 2021; 106:1587-1596. [PMID: 33878233 DOI: 10.1113/ep089337] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2020] [Accepted: 04/15/2021] [Indexed: 11/08/2022]
Abstract
NEW FINDINGS What is the central question of this study? The purpose of this study was to determine whether the nucleotides in a nucleoprotein-enriched diet could ameliorate the unloading-associated decrease in soleus muscle mass and fibre size. What is the main finding and its importance? The results indicate that the nucleotides in the nucleoprotein-enriched diet could ameliorate the unloading-associated decrease in type I fibre size and muscle mass, most probably owing to the activation of protein synthesis pathways and satellite cell proliferation and differentiation via ERK1/2 phosphorylation. Thus, nucleotide supplementation appears to be an effective countermeasure for muscle atrophy. ABSTRACT Hindlimb unloading decreases both the protein synthesis pathway and satellite cell activation and results in muscle atrophy. Nucleotides are included in nucleoprotein and provide the benefits of increasing extracellular signal-regulated kinase (ERK) 1/2 phosphorylation. ERK1/2 phosphorylation is also important in the activation of satellite cells, especially for myoblast proliferation and stimulating protein synthesis pathways. Therefore, we hypothesized that nucleotides in the nucleoproteins would ameliorate muscle atrophy by increasing the protein synthesis pathways and satellite cell activation during hindlimb unloading in rat soleus muscle. Twenty-four female Wistar rats were divided into four groups: control rats fed a basal diet without nucleoprotein (CON), control rats fed a nucleoprotein-enriched diet (CON+NP), hindlimb-unloaded rats fed a basal diet (HU) or hindlimb-unloaded rats fed a nucleoprotein-enriched diet (HU+NP). HU for 2 weeks resulted in reductions in phosphorylation of p70S6K and rpS6, the numbers of myoblast determination protein (MyoD)- and myogenin- positive nuclei, type I muscle fibre size and muscle mass. Both CON+NP and HU+NP rats showed an increase in ERK1/2, phosphorylation of p70S6K and rpS6, and the numbers of MyoD- and myogenin-positive nuclei compared with their basal diet groups. The NP diet also ameliorated the unloading-associated decrease in type I muscle fibre size and muscle mass. The results indicate that the nucleotides in the nucleoprotein-enriched diet could ameliorate the unloading-associated decrease in type I fibre size and muscle mass, most probably owing to the activation of protein synthesis pathways and satellite cell proliferation and differentiation via ERK1/2 phosphorylation. Thus, nucleotide supplementation appears to be an effective countermeasure for muscle atrophy.
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Affiliation(s)
- Ryosuke Nakanishi
- Department of Rehabilitation Science, Kobe University Graduate School of Health Sciences, Kobe, Hyogo, Japan.,Department of Physical Therapy, Faculty of Rehabilitation, Kobe International University, Kobe, Hyogo, Japan
| | - Minoru Tanaka
- Department of Rehabilitation Science, Kobe University Graduate School of Health Sciences, Kobe, Hyogo, Japan.,Department of Physical Therapy, Faculty of Human Science, Osaka University of Human Science, Settsu, Osaka, Japan
| | - Noriaki Maeshige
- Department of Rehabilitation Science, Kobe University Graduate School of Health Sciences, Kobe, Hyogo, Japan
| | - Hiroyo Kondo
- Department of Rehabilitation Science, Kobe University Graduate School of Health Sciences, Kobe, Hyogo, Japan
| | - Roland R Roy
- Brain Research Institute and Department of Integrative Biology and Physiology, University of California, Los Angeles, California, USA
| | - Hidemi Fujino
- Department of Rehabilitation Science, Kobe University Graduate School of Health Sciences, Kobe, Hyogo, Japan
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15
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Prasad V, Millay DP. Skeletal muscle fibers count on nuclear numbers for growth. Semin Cell Dev Biol 2021; 119:3-10. [PMID: 33972174 DOI: 10.1016/j.semcdb.2021.04.015] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2021] [Revised: 03/30/2021] [Accepted: 04/19/2021] [Indexed: 02/06/2023]
Abstract
Skeletal muscle cells are noteworthy for their syncytial nature, with each myofiber accumulating hundreds or thousands of nuclei derived from resident muscle stem cells (MuSCs). These nuclei are accrued through cell fusion, which is controlled by the two essential fusogens Myomaker and Myomerger that are transiently expressed within the myogenic lineage. While the absolute requirement of fusion for muscle development has been known for decades, the underlying need for the magnitude of multinucleation in muscle remains mysterious. Possible advantages of multinucleation include the potential it affords for transcriptional diversity within these massive cells, and as a means of increasing DNA content to support optimal cell size and function. In this article, we review recent advances that elucidate the relationship between myonuclear numbers and establishment of myofiber size, and discuss how this new information refines our understanding of the concept of myonuclear domains (MND), the cytoplasmic volumes that each resident myonucleus can support. Finally, we explore the potential consequences and costs of multinucleation and its impacts on myonuclear transcriptional reserve capacity, growth potential, myofiber size regulation, and muscle adaptability. We anticipate this report will not only serve to highlight the latest advances in the basic biology of syncytial muscle cells but also provide information to help design the next generation of therapeutic strategies to maintain muscle mass and function.
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Affiliation(s)
- Vikram Prasad
- Division of Molecular Cardiovascular Biology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229, USA
| | - Douglas P Millay
- Division of Molecular Cardiovascular Biology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229, USA; Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, OH 45229, USA.
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16
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Solsona R, Pavlin L, Bernardi H, Sanchez AMJ. Molecular Regulation of Skeletal Muscle Growth and Organelle Biosynthesis: Practical Recommendations for Exercise Training. Int J Mol Sci 2021; 22:2741. [PMID: 33800501 PMCID: PMC7962973 DOI: 10.3390/ijms22052741] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2021] [Revised: 03/04/2021] [Accepted: 03/04/2021] [Indexed: 12/18/2022] Open
Abstract
The regulation of skeletal muscle mass and organelle homeostasis is dependent on the capacity of cells to produce proteins and to recycle cytosolic portions. In this investigation, the mechanisms involved in skeletal muscle mass regulation-especially those associated with proteosynthesis and with the production of new organelles-are presented. Thus, the critical roles of mammalian/mechanistic target of rapamycin complex 1 (mTORC1) pathway and its regulators are reviewed. In addition, the importance of ribosome biogenesis, satellite cells involvement, myonuclear accretion, and some major epigenetic modifications related to protein synthesis are discussed. Furthermore, several studies conducted on the topic of exercise training have recognized the central role of both endurance and resistance exercise to reorganize sarcomeric proteins and to improve the capacity of cells to build efficient organelles. The molecular mechanisms underlying these adaptations to exercise training are presented throughout this review and practical recommendations for exercise prescription are provided. A better understanding of the aforementioned cellular pathways is essential for both healthy and sick people to avoid inefficient prescriptions and to improve muscle function with emergent strategies (e.g., hypoxic training). Finally, current limitations in the literature and further perspectives, notably on epigenetic mechanisms, are provided to encourage additional investigations on this topic.
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Affiliation(s)
- Robert Solsona
- Laboratoire Interdisciplinaire Performance Santé Environnement de Montagne (LIPSEM), Faculty of Sports Sciences, University of Perpignan Via Domitia, UR 4640, 7 Avenue Pierre de Coubertin, 66120 Font-Romeu, France;
| | - Laura Pavlin
- DMEM, University of Montpellier, INRAE UMR866, 2 Place Pierre Viala, 34060 Montpellier, France; (L.P.); (H.B.)
| | - Henri Bernardi
- DMEM, University of Montpellier, INRAE UMR866, 2 Place Pierre Viala, 34060 Montpellier, France; (L.P.); (H.B.)
| | - Anthony MJ Sanchez
- Laboratoire Interdisciplinaire Performance Santé Environnement de Montagne (LIPSEM), Faculty of Sports Sciences, University of Perpignan Via Domitia, UR 4640, 7 Avenue Pierre de Coubertin, 66120 Font-Romeu, France;
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17
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Hansson KA, Eftestøl E, Bruusgaard JC, Juvkam I, Cramer AW, Malthe-Sørenssen A, Millay DP, Gundersen K. Myonuclear content regulates cell size with similar scaling properties in mice and humans. Nat Commun 2020; 11:6288. [PMID: 33293572 PMCID: PMC7722898 DOI: 10.1038/s41467-020-20057-8] [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] [Subscribe] [Scholar Register] [Received: 12/11/2019] [Accepted: 10/30/2020] [Indexed: 12/12/2022] Open
Abstract
Muscle fibers are the largest cells in the body, and one of its few syncytia. Individual cell sizes are variable and adaptable, but what governs cell size has been unclear. We find that muscle fibers are DNA scarce compared to other cells, and that the nuclear number (N) adheres to the relationship N = aVb where V is the cytoplasmic volume. N invariably scales sublinearly to V (b < 1), making larger cells even more DNA scarce. N scales linearly to cell surface in adult humans, in adult and developing mice, and in mice with genetically reduced N, but in the latter the relationship eventually fails when they reach adulthood with extremely large myonuclear domains. Another exception is denervation-atrophy where nuclei are not eliminated. In conclusion, scaling exponents are remarkably similar across species, developmental stages and experimental conditions, suggesting an underlying scaling law where DNA-content functions as a limiter of muscle cell size.
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Affiliation(s)
- Kenth-Arne Hansson
- Department of Biosciences, University of Oslo, Oslo, Norway
- Center for Integrative Neuroplasticity, Department of Biosciences, University of Oslo, Oslo, Norway
| | - Einar Eftestøl
- Department of Biosciences, University of Oslo, Oslo, Norway
- Division of Molecular Cardiovascular Biology, Cincinnati Children's Hospital Medical Center, Cincinnati, USA
| | - Jo C Bruusgaard
- Department of Biosciences, University of Oslo, Oslo, Norway
- Center for Integrative Neuroplasticity, Department of Biosciences, University of Oslo, Oslo, Norway
- Department of Health Sciences, Kristiania University College, Oslo, Norway
| | - Inga Juvkam
- Department of Biosciences, University of Oslo, Oslo, Norway
| | - Alyssa W Cramer
- Division of Molecular Cardiovascular Biology, Cincinnati Children's Hospital Medical Center, Cincinnati, USA
| | - Anders Malthe-Sørenssen
- Center for Integrative Neuroplasticity, Department of Biosciences, University of Oslo, Oslo, Norway
- Department of Physics, University of Oslo, Oslo, Norway
| | - Douglas P Millay
- Division of Molecular Cardiovascular Biology, Cincinnati Children's Hospital Medical Center, Cincinnati, USA
- Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, USA
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18
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Cramer AAW, Prasad V, Eftestøl E, Song T, Hansson KA, Dugdale HF, Sadayappan S, Ochala J, Gundersen K, Millay DP. Nuclear numbers in syncytial muscle fibers promote size but limit the development of larger myonuclear domains. Nat Commun 2020; 11:6287. [PMID: 33293533 PMCID: PMC7722938 DOI: 10.1038/s41467-020-20058-7] [Citation(s) in RCA: 47] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2019] [Accepted: 10/30/2020] [Indexed: 12/11/2022] Open
Abstract
Mammalian cells exhibit remarkable diversity in cell size, but the factors that regulate establishment and maintenance of these sizes remain poorly understood. This is especially true for skeletal muscle, comprised of syncytial myofibers that each accrue hundreds of nuclei during development. Here, we directly explore the assumed causal relationship between multinucleation and establishment of normal size through titration of myonuclear numbers during mouse neonatal development. Three independent mouse models, where myonuclear numbers were reduced by 75, 55, or 25%, led to the discovery that myonuclei possess a reserve capacity to support larger functional cytoplasmic volumes in developing myofibers. Surprisingly, the results revealed an inverse relationship between nuclei numbers and reserve capacity. We propose that as myonuclear numbers increase, the range of transcriptional return on a per nuclear basis in myofibers diminishes, which accounts for both the absolute reliance developing myofibers have on nuclear accrual to establish size, and the limits of adaptability in adult skeletal muscle.
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Affiliation(s)
- Alyssa A W Cramer
- Division of Molecular Cardiovascular Biology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, 45229, USA
| | - Vikram Prasad
- Division of Molecular Cardiovascular Biology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, 45229, USA
| | - Einar Eftestøl
- Division of Molecular Cardiovascular Biology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, 45229, USA
- Department of Biosciences, University of Oslo, Oslo, Norway
| | - Taejeong Song
- Department of Internal Medicine, Division of Cardiovascular Health and Disease, University of Cincinnati College of Medicine, Cincinnati, OH, 45229, USA
| | - Kenth-Arne Hansson
- Department of Biosciences, University of Oslo, Oslo, Norway
- Center for Integrative Neuroplasticity (CINPLA), Department of Biosciences, University of Oslo, Oslo, Norway
| | - Hannah F Dugdale
- Center of Human and Applied Physiological Sciences, School of Basic and Medical Biosciences, Faculty of Life Sciences & Medicine, King's College London, London, UK
| | - Sakthivel Sadayappan
- Department of Internal Medicine, Division of Cardiovascular Health and Disease, University of Cincinnati College of Medicine, Cincinnati, OH, 45229, USA
| | - Julien Ochala
- Center of Human and Applied Physiological Sciences, School of Basic and Medical Biosciences, Faculty of Life Sciences & Medicine, King's College London, London, UK
- Randall Center for Cell and Molecular Biophysics, School of Basic & Medical Biosciences, Faculty of Life Sciences & Medicine, Guy's Campus, King's College London, London, UK
- Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
| | | | - Douglas P Millay
- Division of Molecular Cardiovascular Biology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, 45229, USA.
- Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, OH, 45229, USA.
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19
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Oxfeldt M, Dalgaard LB, Jørgensen EB, Johansen FT, Dalgaard EB, Ørtenblad N, Hansen M. Molecular markers of skeletal muscle hypertrophy following 10 wk of resistance training in oral contraceptive users and nonusers. J Appl Physiol (1985) 2020; 129:1355-1364. [PMID: 33054662 DOI: 10.1152/japplphysiol.00562.2020] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
The objective was to determine whether skeletal muscle molecular markers and SC number were influenced differently in users and nonusers of oral contraceptives (OCs) following 10 wk of resistance training. Thirty-eight young healthy untrained users (n = 20) and nonusers of OC (n = 18) completed a 10-wk supervised progressive resistance training program. Before and after the intervention, a muscle tissue sample was obtained from the vastus lateralis muscle for analysis of muscle fiber cross-sectional area (fCSA) and satellite cell (SC) and myonuclei number using immunohistochemistry, gene expression using PCR, protein expression, and myosin heavy chain composition. Following the training period, quadriceps fCSA (P < 0.05), SCs/type I fiber (P = 0.05), and MURF-1 mRNA (P < 0.01) were significantly increased with no difference between the groups. However, SCs/total fiber and SCs/type II fiber increased in OC users only, and SCs/type II fCSA tended (P = 0.055) to be greater in the OC users. Furthermore, in OC users there were a fiber type shift from myosin heavy chain (MHC) IIx to MHC IIa (P < 0.01), and expression of muscle regulatory factor 4 (MRF4) mRNA (P < 0.001) was significantly greater than in non-OC users. Use of second-generation OCs in young untrained women increased skeletal muscle MRF4 expression and SC number following 10 wk of resistance training compared with nonusers.NEW & NOTEWORTHY The effect of oral contraceptive use on the skeletal muscle regulatory pathways in response to resistance training has not been investigated previously. Here we present novel data, demonstrating that use of second-generation oral contraceptives in young untrained women increased skeletal muscle regulatory factor 4 expression and satellite cell number following 10 wk of resistance training compared with nonusers.
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Affiliation(s)
- Mikkel Oxfeldt
- Department of Public Health, Aarhus University, Aarhus, Denmark
| | | | | | | | - Emil Barner Dalgaard
- Department of Clinical Medicine, Diagnostic Centre, Silkeborg Regional Hospital, Silkeborg, Denmark
| | - Niels Ørtenblad
- Department of Sports Science and Clinical Biomechanics, University of Southern Denmark, Odense, Denmark
| | - Mette Hansen
- Department of Public Health, Aarhus University, Aarhus, Denmark
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20
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Kanazashi M, Tanaka M, Maezawa T, Fujino H. Effects of reloading after chronic neuromuscular inactivity on the three-dimensional capillary architecture in rat soleus muscle. Acta Histochem 2020; 122:151617. [PMID: 33066839 DOI: 10.1016/j.acthis.2020.151617] [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: 03/03/2019] [Revised: 08/15/2020] [Accepted: 08/17/2020] [Indexed: 10/23/2022]
Abstract
The purpose of the study was to investigate the effects of ambulatory reloading following hindlimb unloading on the three-dimensional (3D) capillary architecture of rat soleus muscle. In this study, 15 male Sprague-Dawley rats were used. The rats were randomly assigned to the following 3 groups: a normal weight bearing control group (CON), 14 days of hindlimb unloading group (HU), and 14 days of hindlimb unloading followed by 7 days of ambulatory reloading group (HU-RL). The capillary diameter and volume were measured using confocal laser microscopy, and capillary number was determined by two-dimensional (2D) capillary staining in the soleus muscle of each group. The capillary diameter and volume as well as the capillary number were significantly lower in the HU group than in the CON group and significantly higher in the HU-RL group than in the HU group. These results provided novel information about the effectiveness of reloading following unloading on not only the 2D increase in capillary number but also the 3D capillary remodeling in the diameter and volume within the unloaded soleus muscle.
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21
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Snijders T, Aussieker T, Holwerda A, Parise G, Loon LJC, Verdijk LB. The concept of skeletal muscle memory: Evidence from animal and human studies. Acta Physiol (Oxf) 2020; 229:e13465. [PMID: 32175681 PMCID: PMC7317456 DOI: 10.1111/apha.13465] [Citation(s) in RCA: 45] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2019] [Revised: 03/05/2020] [Accepted: 03/10/2020] [Indexed: 12/18/2022]
Abstract
Within the current paradigm of the myonuclear domain theory, it is postulated that a linear relationship exists between muscle fibre size and myonuclear content. The myonuclear domain is kept (relatively) constant by adding additional nuclei (supplied by muscle satellite cells) during muscle fibre hypertrophy and nuclear loss (by apoptosis) during muscle fibre atrophy. However, data from recent animal studies suggest that myonuclei that are added to support muscle fibre hypertrophy are not lost within various muscle atrophy models. Such myonuclear permanence has been suggested to constitute a mechanism allowing the muscle fibre to (re)grow more efficiently during retraining, a phenomenon referred to as "muscle memory." The concept of "muscle memory by myonuclear permanence" has mainly been based on data attained from rodent experimental models. Whether the postulated mechanism also holds true in humans remains largely ambiguous. Nevertheless, there are several studies in humans that provide evidence to potentially support or contradict (parts of) the muscle memory hypothesis. The goal of the present review was to discuss the evidence for the existence of "muscle memory" in both animal and human models of muscle fibre hypertrophy as well as atrophy. Furthermore, to provide additional insight in the potential presence of muscle memory by myonuclear permanence in humans, we present new data on previously performed exercise training studies. Finally, suggestions for future research are provided to establish whether muscle memory really exists in humans.
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Affiliation(s)
- Tim Snijders
- Department of Human Biology NUTRIM School of Nutrition and Translational Research in Metabolism Maastricht University Maastricht the Netherlands
| | - Thorben Aussieker
- Department of Human Biology NUTRIM School of Nutrition and Translational Research in Metabolism Maastricht University Maastricht the Netherlands
| | - Andy Holwerda
- Department of Human Biology NUTRIM School of Nutrition and Translational Research in Metabolism Maastricht University Maastricht the Netherlands
| | - Gianni Parise
- Department of Kinesiology and Medical Physics & Applied Radiation Sciences McMaster University Hamilton ON Canada
| | - Luc J. C. Loon
- Department of Human Biology NUTRIM School of Nutrition and Translational Research in Metabolism Maastricht University Maastricht the Netherlands
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22
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Ato S, Kido K, Sase K, Fujita S. Response of Resistance Exercise-Induced Muscle Protein Synthesis and Skeletal Muscle Hypertrophy Are Not Enhanced After Disuse Muscle Atrophy in Rat. Front Physiol 2020; 11:469. [PMID: 32528306 PMCID: PMC7258402 DOI: 10.3389/fphys.2020.00469] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2020] [Accepted: 04/16/2020] [Indexed: 01/26/2023] Open
Abstract
Skeletal muscle disuse rapidly decreases muscle mass. Resistance training (RT) is believed as the most effective way to gain muscle mass via an increase in mTORC1 activity and muscle protein synthesis (MPS). However, it remains unclear whether muscle atrophy by disuse alters the mTORC1 activation and MPS response to an acute resistance exercise (RE) and chronic RT-mediated skeletal muscle hypertrophy. This study investigated the influence of disuse muscle atrophy on the response of mTORC1 activation and MPS to an acute RE. We also evaluated whether disuse muscle atrophy affects the response of RT-induced muscle mass gain. Thirty male Sprague-Dawley rats were randomly divided into control (CON) or hindlimb suspension (HS) groups. A 14-day HS via the tail was used as the model for gastrocnemius muscle disuse in the HS group. Unilateral lower limb muscle contraction using by percutaneous electrical stimulation was used to mimic the stimuli of RE. Ten bouts of RE were performed in 3-week as chronic RT. Our results showed that MPS and mTORC1 activity was unchanged after HS at basal state. However, the ribosomal RNA (rRNA) level was reduced in HS rats compared to that in CON rats at basal state. MPS and rRNA increased in both HS and CON rats in response to acute RE to the same extent. However, the level of mTORC1 activation in response to an acute RE was significantly higher in HS than that in the CON group at 12 h after exercise, even though no difference was observed at 3 h after exercise. The 10-bout RT significantly increased gastrocnemius muscle mass in both CON and HS rats. The response of muscle hypertrophy did not differ between the groups. Therefore, MPS in response to acute RE and muscle hypertrophy in response to chronic RT were unaltered after disuse muscle atrophy.
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Affiliation(s)
- Satoru Ato
- Graduate School of Sport and Health Science, Ritsumeikan University, Shiga, Japan.,Department of Life Science and Applied Chemistry, Nagoya Institute of Technology, Nagoya, Japan
| | - Kohei Kido
- Graduate School of Sport and Health Science, Ritsumeikan University, Shiga, Japan.,Laboratory of Sports and Exercise Medicine, Graduate School of Human and Environmental Studies, Kyoto University, Kyoto, Japan
| | - Kohei Sase
- Graduate School of Sport and Health Science, Ritsumeikan University, Shiga, Japan
| | - Satoshi Fujita
- Graduate School of Sport and Health Science, Ritsumeikan University, Shiga, Japan
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23
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The effect of resistance training, detraining and retraining on muscle strength and power, myofibre size, satellite cells and myonuclei in older men. Exp Gerontol 2020; 133:110860. [DOI: 10.1016/j.exger.2020.110860] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2019] [Revised: 01/30/2020] [Accepted: 01/31/2020] [Indexed: 01/05/2023]
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24
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Arentson-Lantz EJ, Fiebig KN, Anderson-Catania KJ, Deer RR, Wacher A, Fry CS, Lamon S, Paddon-Jones D. Countering disuse atrophy in older adults with low-volume leucine supplementation. J Appl Physiol (1985) 2020; 128:967-977. [PMID: 32191600 DOI: 10.1152/japplphysiol.00847.2019] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Older adults are at increased risk of being bedridden and experiencing negative health outcomes including the loss of muscle tissue and functional capacity. We hypothesized that supplementing daily meals with a small quantity (3-4 g/meal) of leucine would partially preserve lean leg mass and function of older adults during bed rest. During a 7-day bed rest protocol, followed by 5 days of inpatient rehabilitation, healthy older men and women (67.8 ± 1.1 yr, 14 men; 6 women) were randomized to receive isoenergetic meals supplemented with leucine (LEU, 0.06 g/kg/meal; n = 10) or an alanine control (CON, 0.06 g/kg/meal; n = 10). Outcomes were assessed at baseline, following bed rest, and after rehabilitation. Body composition was measured by dual-energy X-ray absorptiometry. Functional capacity was assessed by knee extensor isokinetic and isometric dynamometry, peak aerobic capacity, and the short physical performance battery. Muscle fiber type, cross-sectional area, signaling protein expression levels, and single fiber characteristics were determined from biopsies of the vastus lateralis. Leucine supplementation reduced the loss of leg lean mass during bed rest (LEU vs. CON: -423 vs. -1035 ± 143 g; P = 0.008) but had limited impact on strength or endurance-based functional outcomes. Similarly, leucine had no effect on markers of anabolic signaling and protein degradation during bed rest or rehabilitation. In conclusion, providing older adults with supplemental leucine has minimal impact on total energy or protein consumption and has the potential to partially counter some, but not all, of the negative effects of inactivity on muscle health.NEW & NOTEWORTHY Skeletal muscle morphology and function in older adults was significantly compromised by 7 days of disuse. Leucine supplementation partially countered the loss of lean leg mass but did not preserve muscle function or positively impact changes at the muscle fiber level associated with bed rest or rehabilitation. Of note, our data support a relationship between myonuclear content and adaptations to muscle atrophy at the whole limb and single fiber level.
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Affiliation(s)
- Emily J Arentson-Lantz
- Department of Nutrition and Metabolism, University of Texas Medical Branch, Galveston, Texas.,Center for Recovery, Physical Activity and Nutrition, University of Texas Medical Branch, Galveston, Texas
| | - Kinga N Fiebig
- Institute for Physical Activity and Nutrition (IPAN), Faculty of Health, Deakin University, Melbourne, Australia
| | - Kim J Anderson-Catania
- Institute for Physical Activity and Nutrition (IPAN), Faculty of Health, Deakin University, Melbourne, Australia
| | - Rachel R Deer
- Center for Recovery, Physical Activity and Nutrition, University of Texas Medical Branch, Galveston, Texas.,Division of Rehabilitation Sciences, University of Texas Medical Branch, Galveston, Texas
| | - Adam Wacher
- Department of Anesthesiology, University of Texas Medical Branch, Galveston, Texas
| | - Christopher S Fry
- Department of Nutrition and Metabolism, University of Texas Medical Branch, Galveston, Texas.,Center for Recovery, Physical Activity and Nutrition, University of Texas Medical Branch, Galveston, Texas
| | - Séverine Lamon
- Institute for Physical Activity and Nutrition (IPAN), Faculty of Health, Deakin University, Melbourne, Australia
| | - Douglas Paddon-Jones
- Department of Nutrition and Metabolism, University of Texas Medical Branch, Galveston, Texas.,Center for Recovery, Physical Activity and Nutrition, University of Texas Medical Branch, Galveston, Texas
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25
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Qaisar R, Karim A, Elmoselhi AB. Muscle unloading: A comparison between spaceflight and ground-based models. Acta Physiol (Oxf) 2020; 228:e13431. [PMID: 31840423 DOI: 10.1111/apha.13431] [Citation(s) in RCA: 43] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2019] [Revised: 12/09/2019] [Accepted: 12/12/2019] [Indexed: 12/12/2022]
Abstract
Prolonged unloading of skeletal muscle, a common outcome of events such as spaceflight, bed rest and hindlimb unloading, can result in extensive metabolic, structural and functional changes in muscle fibres. With advancement in investigations of cellular and molecular mechanisms, understanding of disuse muscle atrophy has significantly increased. However, substantial gaps exist in our understanding of the processes dictating muscle plasticity during unloading, which prevent us from developing effective interventions to combat muscle loss. This review aims to update the status of knowledge and underlying mechanisms leading to cellular and molecular changes in skeletal muscle during unloading. We have also discussed advances in the understanding of contractile dysfunction during spaceflights and in ground-based models of muscle unloading. Additionally, we have elaborated on potential therapeutic interventions that show promising results in boosting muscle mass and strength during mechanical unloading. Finally, we have identified key gaps in our knowledge as well as possible research direction for the future.
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Affiliation(s)
- Rizwan Qaisar
- Department of Basic Medical Sciences College of Medicine University of Sharjah Sharjah UAE
| | - Asima Karim
- Department of Basic Medical Sciences College of Medicine University of Sharjah Sharjah UAE
| | - Adel B. Elmoselhi
- Department of Basic Medical Sciences College of Medicine University of Sharjah Sharjah UAE
- Department of Physiology Michigan State University East Lansing MI USA
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Eftestøl E, Psilander N, Cumming KT, Juvkam I, Ekblom M, Sunding K, Wernbom M, Holmberg HC, Ekblom B, Bruusgaard JC, Raastad T, Gundersen K. Muscle memory: are myonuclei ever lost? J Appl Physiol (1985) 2019; 128:456-457. [PMID: 31854249 DOI: 10.1152/japplphysiol.00761.2019] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Affiliation(s)
- Einar Eftestøl
- Department of Biosciences, University of Oslo, Oslo, Norway
| | - Niklas Psilander
- Department of Sport Performance and Training, The Swedish School of Sport and Health Sciences (GIH), Stockholm, Sweden
| | | | - Inga Juvkam
- Department of Biosciences, University of Oslo, Oslo, Norway
| | - Maria Ekblom
- Department of Sport Performance and Training, The Swedish School of Sport and Health Sciences (GIH), Stockholm, Sweden
| | - Kerstin Sunding
- Stockholm Sport Trauma Research Center, Karolinska Institutet, Stockholm, Sweden
| | - Mathias Wernbom
- Center for Health and Performance, Department of Food and Nutrition and Sport Science, University of Gothenburg, Gothenburg, Sweden
| | - Hans-Christer Holmberg
- Swedish Winter Sports Research Centre, Department of Health Sciences, Mid Sweden University, Östersund, Sweden
| | - Björn Ekblom
- Department of Sport Performance and Training, The Swedish School of Sport and Health Sciences (GIH), Stockholm, Sweden
| | - Jo C Bruusgaard
- Department of Biosciences, University of Oslo, Oslo, Norway.,Department of Health Sciences, Kristiania University College, Oslo, Norway
| | - Truls Raastad
- Department of Physical Performance, Norwegian School of Sport Sciences, Oslo, Norway
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Sanz G, Martínez-Aranda LM, Tesch PA, Fernandez-Gonzalo R, Lundberg TR. Muscle2View, a CellProfiler pipeline for detection of the capillary-to-muscle fiber interface and high-content quantification of fiber type-specific histology. J Appl Physiol (1985) 2019; 127:1698-1709. [DOI: 10.1152/japplphysiol.00257.2019] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Because manual immunohistochemical analysis of features such as skeletal muscle fiber typing, capillaries, myonuclei, and fiber size-related parameters is time consuming and prone to user subjectivity, automatic computational methods could allow for faster and more objective evaluation. Here, we developed Muscle2View, a free CellProfiler-based pipeline that integrates all key fiber-morphological variables, including the novel quantification of the capillary-to-fiber interface, in one single tool. Provided that the images are of sufficient quality and the settings are configured for the specific study, the pipeline allows for automatic and unsupervised analysis of fiber borders, myonuclei, capillaries, and morphometric parameters in a fiber type-specific manner from large batches of images in <10 min/tissue sample. The novel identification of the capillary-to-fiber interface allowed for the calculation of microvascular factors such as capillary contacts (CC), individual capillary-to-fiber ratio (C/Fi), and capillary-to-fiber perimeter exchange (CFPE) index. When comparing the Muscle2View pipeline to manual or semiautomatic analysis, overall the results revealed strong correlations. For several variables, however, there were differences (5–15%) between values computed by manual counting and Muscle2View, suggesting that the methods should not necessarily be used interchangeably. Collectively, we demonstrate that the Muscle2View pipeline can provide unbiased and high-content analysis of muscle cross-sectional immunohistochemistry images. In addition to the classical morphological measurements, the Muscle2View can identify the complex capillary-to-fiber network and myonuclear density in a fiber type-specific manner. This robust analysis is done in one single run within a user-friendly and flexible environment based on the free and widely used image software CellProfiler. NEW & NOTEWORTHY Here, we developed a freely available CellProfiler-based pipeline termed Muscle2View, which provides unbiased, high-content analysis of muscle cross-sectional immunohistochemistry images. In addition to fiber typing, myonuclei counting, and the quantification of fiber type-specific morphological measurements, the Muscle2View pipeline can identify the complex capillary-to-fiber network from a batch of images within minutes. Thus, the Muscle2View is a viable tool for researchers aiming to quantify immunohistochemical variables from skeletal muscle biopsies.
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Affiliation(s)
- Gema Sanz
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Stockholm, Sweden
- Gnomics, Murcia, Spain
| | - Luis Manuel Martínez-Aranda
- Faculty of Sport, Neuroscience of Human Movement Research Group (Neuromove), Catholic University of San Antonio, Murcia, Spain
- Division of Clinical Physiology, Department of Laboratory Medicine, Karolinska Institutet, and Unit of Clinical Physiology, Karolinska University Hospital, Stockholm, Sweden
| | - Per A. Tesch
- Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden
| | - Rodrigo Fernandez-Gonzalo
- Division of Clinical Physiology, Department of Laboratory Medicine, Karolinska Institutet, and Unit of Clinical Physiology, Karolinska University Hospital, Stockholm, Sweden
| | - Tommy R. Lundberg
- Division of Clinical Physiology, Department of Laboratory Medicine, Karolinska Institutet, and Unit of Clinical Physiology, Karolinska University Hospital, Stockholm, Sweden
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28
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Grönholdt‐Klein M, Altun M, Becklén M, Dickman Kahm E, Fahlström A, Rullman E, Ulfhake B. Muscle atrophy and regeneration associated with behavioural loss and recovery of function after sciatic nerve crush. Acta Physiol (Oxf) 2019; 227:e13335. [PMID: 31199566 DOI: 10.1111/apha.13335] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2019] [Revised: 05/31/2019] [Accepted: 06/11/2019] [Indexed: 12/22/2022]
Abstract
AIM To resolve timing and coordination of denervation atrophy and the re-innervation recovery process to discern correlations indicative of common programs governing these processes. METHODS Female Sprague-Dawley (SD) rats had a unilateral sciatic nerve crush. Based on longitudinal behavioural observations, the triceps surae muscle was analysed at different time points post-lesion. RESULTS Crush results in a loss of muscle function and mass (-30%) followed by a recovery to almost pre-lesion status at 30 days post-crush (dpc). There was no loss of fibres nor any significant change in the number of nuclei per fibre but a shift in fibres expressing myosins I and II that reverted back to control levels at 30 dpc. A residual was the persistence of hybrid fibres. Early on a CHNR -ε to -γ switch and a re-expression of embryonic MyHC showed as signs of denervation. Foxo1, Smad3, Fbxo32 and Trim63 transcripts were upregulated but not Myostatin, InhibinA and ActivinR2B. Combined this suggests that the mechanism instigating atrophy provides a selectivity of pathway(s) activated. The myogenic differentiation factors (MDFs: Myog, Myod1 and Myf6) were upregulated early on suggesting a role also in the initial atrophy. The regulation of these transcripts returned towards baseline at 30 dpc. The examined genes showed a strong baseline covariance in transcript levels which dissolved in the response to crush driven mainly by the MDFs. At 30 dpc the naïve expression pattern was re-established. CONCLUSION Peripheral nerve crush offers an excellent model to assess and interfere with muscle adaptions to denervation and re-innervation.
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Affiliation(s)
| | - Mikael Altun
- Department of Laboratory Medicine Karolinska Institutet Huddinge Sweden
| | - Meneca Becklén
- Department of Neuroscience Karolinska Institutet Stockholm Sweden
| | | | - Andreas Fahlström
- Department of Neuroscience Karolinska Institutet Stockholm Sweden
- Department of Neuroscience, Neurosurgery Uppsala University Uppsala Sweden
| | - Eric Rullman
- Department of Laboratory Medicine Karolinska Institutet Huddinge Sweden
| | - Brun Ulfhake
- Department of Neuroscience Karolinska Institutet Stockholm Sweden
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29
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Sieljacks P, Wang J, Groennebaek T, Rindom E, Jakobsgaard JE, Herskind J, Gravholt A, Møller AB, Musci RV, de Paoli FV, Hamilton KL, Miller BF, Vissing K. Six Weeks of Low-Load Blood Flow Restricted and High-Load Resistance Exercise Training Produce Similar Increases in Cumulative Myofibrillar Protein Synthesis and Ribosomal Biogenesis in Healthy Males. Front Physiol 2019; 10:649. [PMID: 31191347 PMCID: PMC6548815 DOI: 10.3389/fphys.2019.00649] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2018] [Accepted: 05/08/2019] [Indexed: 12/25/2022] Open
Abstract
Purpose: High-load resistance exercise contributes to maintenance of muscle mass, muscle protein quality, and contractile function by stimulation of muscle protein synthesis (MPS), hypertrophy, and strength gains. However, high loading may not be feasible in several clinical populations. Low-load blood flow restricted resistance exercise (BFRRE) may provide an alternative approach. However, the long-term protein synthetic response to BFRRE is unknown and the myocellular adaptations to prolonged BFRRE are not well described. Methods: To investigate this, 34 healthy young subjects were randomized to 6 weeks of low-load BFRRE, HLRE, or non-exercise control (CON). Deuterium oxide (D2O) was orally administered throughout the intervention period. Muscle biopsies from m. vastus lateralis were collected before and after the 6-week intervention period to assess long-term myofibrillar MPS and RNA synthesis as well as muscle fiber-type-specific cross-sectional area (CSA), satellite cell content, and myonuclei content. Muscle biopsies were also collected in the immediate hours following single-bout exercise to assess signaling for muscle protein degradation. Isometric and dynamic quadriceps muscle strength was evaluated before and after the intervention. Results: Myofibrillar MPS was higher in BFRRE (1.34%/day, p < 0.01) and HLRE (1.12%/day, p < 0.05) compared to CON (0.96%/day) with no significant differences between exercise groups. Muscle RNA synthesis was higher in BFRRE (0.65%/day, p < 0.001) and HLRE (0.55%/day, p < 0.01) compared to CON (0.38%/day) and both training groups increased RNA content, indicating ribosomal biogenesis in response to exercise. BFRRE and HLRE both activated muscle degradation signaling. Muscle strength increased 6-10% in BFRRE (p < 0.05) and 13-23% in HLRE (p < 0.01). Dynamic muscle strength increased to a greater extent in HLRE (p < 0.05). No changes in type I and type II muscle fiber-type-specific CSA, satellite cell content, or myonuclei content were observed. Conclusions: These results demonstrate that BFRRE increases long-term muscle protein turnover, ribosomal biogenesis, and muscle strength to a similar degree as HLRE. These findings emphasize the potential application of low-load BFRRE to stimulate muscle protein turnover and increase muscle function in clinical populations where high loading is untenable.
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Affiliation(s)
- Peter Sieljacks
- Section for Sports Science, Department of Public Health, Aarhus University, Aarhus, Denmark
| | - Jakob Wang
- Section for Sports Science, Department of Public Health, Aarhus University, Aarhus, Denmark
| | - Thomas Groennebaek
- Section for Sports Science, Department of Public Health, Aarhus University, Aarhus, Denmark
| | - Emil Rindom
- Department of Biomedicine, Aarhus University, Aarhus, Denmark
| | | | - Jon Herskind
- Section for Sports Science, Department of Public Health, Aarhus University, Aarhus, Denmark
| | - Anders Gravholt
- Section for Sports Science, Department of Public Health, Aarhus University, Aarhus, Denmark
| | - Andreas B. Møller
- Steno Diabetes Center Aarhus, Aarhus University Hospital, Aarhus, Denmark
| | - Robert V. Musci
- Department of Health and Exercise Science, Colorado State University, Fort Collins, CO, United States
| | | | - Karyn L. Hamilton
- Department of Health and Exercise Science, Colorado State University, Fort Collins, CO, United States
| | - Benjamin F. Miller
- Aging and Metabolism Research Program, Oklahoma Medical Research Foundation, Oklahoma City, OK, United States
| | - Kristian Vissing
- Section for Sports Science, Department of Public Health, Aarhus University, Aarhus, Denmark
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30
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Kawamura N, Ohnuki Y, Matsuo I, Suita K, Ishikawa M, Mototani Y, Shiozawa K, Ito A, Yagisawa Y, Hayakawa Y, Nariyama M, Umeki D, Ujiie Y, Gomi K, Okumura S. Effects of chronic Porphyromonas gingivalis lipopolysaccharide infusion on skeletal muscles in mice. J Physiol Sci 2019; 69:503-511. [PMID: 30848475 PMCID: PMC10717087 DOI: 10.1007/s12576-019-00670-z] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2018] [Accepted: 02/23/2019] [Indexed: 10/27/2022]
Abstract
Periodontitis, which is caused by various oral organisms, predominantly affects adults, and is one of the main causes of tooth loss, as well as leading to progression of numerous systemic diseases. However, its relationship to sarcopenia (aging-associated degenerative loss of skeletal muscle mass and function) remains unclear. The aim of this study was to investigate the effects of Porphyromonas gingivalis lipopolysaccharide (PG-LPS) on skeletal muscle in mice, and to establish the underlying mechanisms. Mice (C57BL/6) were injected with PG-LPS (0.8 mg/kg/day) for 4 weeks. This treatment significantly decreased the weight of fast-twitch skeletal muscles (masseter and tibialis anterior muscles), but not that of slow-twitch skeletal muscle (soleus muscle). The area of fibrosis was significantly increased in masseter muscle, but remained unchanged in the other two muscles. The number of apoptotic myocytes was significantly increased (approximately eightfold) in masseter muscle. These data suggest that persistent subclinical exposure to PG-LPS might reduce the size of fast-twitch skeletal muscle, but not slow-twitch skeletal muscle. Masseter muscle appears to be especially susceptible to the adverse effects of PG-LPS, because muscle remodeling (muscle fibrosis and myocyte apoptosis) was induced solely in masseter muscle. Thus, periodontitis might be one of the major causes of oral sarcopenia.
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Affiliation(s)
- Naoya Kawamura
- Department of Physiology, Tsurumi University School of Dental Medicine, 2-1-3 Tsurumi, Tsurumi-ku, Yokohama, 230-8501, Japan
- Department of Periodontology, Tsurumi University School of Dental Medicine, Yokohama, 230-8501, Japan
| | - Yoshiki Ohnuki
- Department of Physiology, Tsurumi University School of Dental Medicine, 2-1-3 Tsurumi, Tsurumi-ku, Yokohama, 230-8501, Japan
| | - Ichiro Matsuo
- Department of Physiology, Tsurumi University School of Dental Medicine, 2-1-3 Tsurumi, Tsurumi-ku, Yokohama, 230-8501, Japan
- Department of Periodontology, Tsurumi University School of Dental Medicine, Yokohama, 230-8501, Japan
| | - Kenji Suita
- Department of Physiology, Tsurumi University School of Dental Medicine, 2-1-3 Tsurumi, Tsurumi-ku, Yokohama, 230-8501, Japan
| | - Misao Ishikawa
- Department of Oral Anatomy, Tsurumi University School of Dental Medicine, Yokohama, 230-8501, Japan
| | - Yasumasa Mototani
- Department of Physiology, Tsurumi University School of Dental Medicine, 2-1-3 Tsurumi, Tsurumi-ku, Yokohama, 230-8501, Japan
| | - Kouichi Shiozawa
- Department of Physiology, Tsurumi University School of Dental Medicine, 2-1-3 Tsurumi, Tsurumi-ku, Yokohama, 230-8501, Japan
| | - Aiko Ito
- Department of Physiology, Tsurumi University School of Dental Medicine, 2-1-3 Tsurumi, Tsurumi-ku, Yokohama, 230-8501, Japan
- Department of Orthodontics, Tsurumi University School of Dental Medicine, Yokohama, 230-8501, Japan
| | - Yuka Yagisawa
- Department of Physiology, Tsurumi University School of Dental Medicine, 2-1-3 Tsurumi, Tsurumi-ku, Yokohama, 230-8501, Japan
- Department of Orthodontics, Tsurumi University School of Dental Medicine, Yokohama, 230-8501, Japan
| | - Yoshio Hayakawa
- Department of Physiology, Tsurumi University School of Dental Medicine, 2-1-3 Tsurumi, Tsurumi-ku, Yokohama, 230-8501, Japan
- Department of Dental Anesthesiology, Tsurumi University School of Dental Medicine, Yokohama, 230-8501, Japan
| | - Megumi Nariyama
- Department of Pediatric Dentistry, Tsurumi University School of Dental Medicine, Yokohama, 236-8501, Japan
| | - Daisuke Umeki
- Department of Orthodontics, Tsurumi University School of Dental Medicine, Yokohama, 230-8501, Japan
| | - Yuko Ujiie
- Department of Periodontology, Tsurumi University School of Dental Medicine, Yokohama, 230-8501, Japan
| | - Kazuhiro Gomi
- Department of Periodontology, Tsurumi University School of Dental Medicine, Yokohama, 230-8501, Japan
| | - Satoshi Okumura
- Department of Physiology, Tsurumi University School of Dental Medicine, 2-1-3 Tsurumi, Tsurumi-ku, Yokohama, 230-8501, Japan.
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31
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Ito A, Ohnuki Y, Suita K, Ishikawa M, Mototani Y, Shiozawa K, Kawamura N, Yagisawa Y, Nariyama M, Umeki D, Nakamura Y, Okumura S. Role of β-adrenergic signaling in masseter muscle. PLoS One 2019; 14:e0215539. [PMID: 30986276 PMCID: PMC6464212 DOI: 10.1371/journal.pone.0215539] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2018] [Accepted: 04/03/2019] [Indexed: 02/07/2023] Open
Abstract
In skeletal muscle, the major isoform of β-adrenergic receptor (β-AR) is β2-AR and the minor isoform is β1-AR, which is opposite to the situation in cardiac muscle. Despite extensive studies in cardiac muscle, the physiological roles of the β-AR subtypes in skeletal muscle are not fully understood. Therefore, in this work, we compared the effects of chronic β1- or β2-AR activation with a specific β1-AR agonist, dobutamine (DOB), or a specific β2-AR agonist, clenbuterol (CB), on masseter and cardiac muscles in mice. In cardiac muscle, chronic β1-AR stimulation induced cardiac hypertrophy, fibrosis and myocyte apoptosis, whereas chronic β2-AR stimulation induced cardiac hypertrophy without histological abnormalities. In masseter muscle, however, chronic β1-AR stimulation did not induce muscle hypertrophy, but did induce fibrosis and apoptosis concomitantly with increased levels of p44/42 MAPK (ERK1/2) (Thr-202/Tyr-204), calmodulin kinase II (Thr-286) and mammalian target of rapamycin (mTOR) (Ser-2481) phosphorylation. On the other hand, chronic β2-AR stimulation in masseter muscle induced muscle hypertrophy without histological abnormalities, as in the case of cardiac muscle, concomitantly with phosphorylation of Akt (Ser-473) and mTOR (Ser-2448) and increased expression of microtubule-associated protein light chain 3-II, an autophagosome marker. These results suggest that the β1-AR pathway is deleterious and the β2-AR is protective in masseter muscle. These data should be helpful in developing pharmacological approaches for the treatment of skeletal muscle wasting and weakness.
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Affiliation(s)
- Aiko Ito
- Department of Physiology, Tsurumi University School of Dental Medicine, Yokohama, Japan
- Department of Orthodontics, Tsurumi University School of Dental Medicine, Yokohama, Japan
| | - Yoshiki Ohnuki
- Department of Physiology, Tsurumi University School of Dental Medicine, Yokohama, Japan
| | - Kenji Suita
- Department of Physiology, Tsurumi University School of Dental Medicine, Yokohama, Japan
| | - Misao Ishikawa
- Department of Oral Anatomy, Tsurumi University School of Dental Medicine, Yokohama, Japan
| | - Yasumasa Mototani
- Department of Physiology, Tsurumi University School of Dental Medicine, Yokohama, Japan
| | - Kouichi Shiozawa
- Department of Physiology, Tsurumi University School of Dental Medicine, Yokohama, Japan
| | - Naoya Kawamura
- Department of Physiology, Tsurumi University School of Dental Medicine, Yokohama, Japan
- Department of Periodontology, Tsurumi University School of Dental Medicine, Yokohama, Japan
| | - Yuka Yagisawa
- Department of Physiology, Tsurumi University School of Dental Medicine, Yokohama, Japan
- Department of Orthodontics, Tsurumi University School of Dental Medicine, Yokohama, Japan
| | - Megumi Nariyama
- Department of Pediatric Dentistry, Tsurumi University School of Dental Medicine, Yokohama, Japan
| | - Daisuke Umeki
- Department of Orthodontics, Tsurumi University School of Dental Medicine, Yokohama, Japan
| | - Yoshiki Nakamura
- Department of Orthodontics, Tsurumi University School of Dental Medicine, Yokohama, Japan
| | - Satoshi Okumura
- Department of Physiology, Tsurumi University School of Dental Medicine, Yokohama, Japan
- * E-mail:
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Psilander N, Eftestøl E, Cumming KT, Juvkam I, Ekblom MM, Sunding K, Wernbom M, Holmberg HC, Ekblom B, Bruusgaard JC, Raastad T, Gundersen K. Effects of training, detraining, and retraining on strength, hypertrophy, and myonuclear number in human skeletal muscle. J Appl Physiol (1985) 2019; 126:1636-1645. [PMID: 30991013 DOI: 10.1152/japplphysiol.00917.2018] [Citation(s) in RCA: 41] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Previously trained mouse muscles acquire strength and volume faster than naïve muscles; it has been suggested that this is related to increased myonuclear density. The present study aimed to determine whether a previously strength-trained leg (mem-leg) would respond better to a period of strength training than a previously untrained leg (con-leg). Nine men and 10 women performed unilateral strength training (T1) for 10 wk, followed by 20 wk of detraining (DT) and a 5-wk bilateral retraining period (T2). Muscle biopsies were taken before and after each training period and analyzed for myonuclear number, fiber volume, and cross-sectional area (CSA). Ultrasound and one repetition of maximum leg extension were performed to determine muscle thickness (MT) and strength. CSA (~17%), MT (~10%), and strength (~20%) increased during T1 in the mem-leg. However, the myonuclear number and fiber volume did not change. MT and CSA returned to baseline values during DT, but strength remained elevated (~60%), supporting previous findings of a long-lasting motor learning effect. MT and strength increased similarly in the mem-leg and con-leg during T2, whereas CSA, fiber volume, and myonuclear number remained unaffected. In conclusion, training response during T2 did not differ between the mem-leg and con-leg. However, this does not discount the existence of human muscle memory, since no increase in the number of myonuclei was detected during T1 and no clear detraining effect was observed for cell size during DT; thus, the present data did not allow for a rigorous test of the muscle memory hypothesis. NEW & NOTEWORTHY If a long-lasting intramuscular memory exists in humans, this will affect strength-training advice for both athletes and the public. Based on animal experiments, we hypothesized that such a memory exists and that it is related to the myonuclear number. However, a period of unilateral strength training, followed by detraining, did not increase the myonuclear number. The training response, during a subsequent bilateral retraining period, was not enhanced in the previously trained leg.
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Affiliation(s)
- Niklas Psilander
- Department of Sport Performance and Training, The Swedish School of Sport and Health Sciences , Stockholm , Sweden
| | - Einar Eftestøl
- Department of Biosciences, University of Oslo , Oslo , Norway
| | | | - Inga Juvkam
- Department of Biosciences, University of Oslo , Oslo , Norway
| | - Maria M Ekblom
- Department of Sport Performance and Training, The Swedish School of Sport and Health Sciences , Stockholm , Sweden
| | - Kerstin Sunding
- Stockholm Sport Trauma Research Center, Karolinska Institutet , Stockholm , Sweden
| | - Mathias Wernbom
- Department of Food and Nutrition and Sport Science, Center for Health and Performance, University of Gothenburg , Gothenburg , Sweden
| | - Hans-Christer Holmberg
- Department of Health Sciences, Swedish Winter Sports Research Centre, Mid Sweden University, Östersund, Sweden
| | - Björn Ekblom
- Department of Sport Performance and Training, The Swedish School of Sport and Health Sciences , Stockholm , Sweden
| | - Jo C Bruusgaard
- Department of Biosciences, University of Oslo , Oslo , Norway.,Department of Health Sciences, Kristiania University College , Oslo , Norway
| | - Truls Raastad
- Department of Physical Performance, Norwegian School of Sport Sciences , Oslo , Norway
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Winje IM, Sheng X, Hansson K, Solbrå A, Tennøe S, Saatcioglu F, Bruusgaard JC, Gundersen K. Cachexia does not induce loss of myonuclei or muscle fibres during xenografted prostate cancer in mice. Acta Physiol (Oxf) 2019; 225:e13204. [PMID: 30325108 DOI: 10.1111/apha.13204] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2018] [Revised: 10/02/2018] [Accepted: 10/08/2018] [Indexed: 12/25/2022]
Abstract
AIM Cachexia is a severe wasting disorder involving loss of body- and muscle mass reducing survival and quality of life in cancer patients. We aim at determining if cachexia is a mere perturbation of the protein balance or if the condition also involves a degenerative loss of myonuclei within the fibre syncytia or loss of whole muscle fibres. METHODS We induced cachexia by xenografting PC3 prostate cancer cells in nu/nu mice. Six weeks later, we counted myonuclei by in vivo microscopic imaging of single live fibres in the extensor digitorum longus muscle (EDL), and the EDL, soleus and tibialis anterior muscles were also harvested for ex vivo histology. RESULTS The mice lost on average 15% of the whole-body wt. The muscle wet weight of the glycolytic, fast EDL was reduced by 14%, the tibialis anterior by 17%, and the slow, oxidative soleus by 6%. The fibre cross-sectional area in the EDL was reduced by 21% with no loss of myonuclei or any significant reduction in the number of muscle fibres. TUNEL-positive nuclei or fibres with embryonic myosin were rare both in cachectic and control muscles, and haematoxylin-eosin staining revealed no clear signs of muscle pathology. CONCLUSION The data suggest that the cachexia induced by xenografted prostate tumours induces a pronounced atrophy not accompanied by a loss of myonuclei or a loss of muscle fibres. Thus, stem cell related treatment might be redundant, and the quest for treatment options should rather focus on intervening with intracellular pathways regulating muscle fibre size.
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Affiliation(s)
| | - Xia Sheng
- Department of Biosciences University of Oslo Oslo Norway
| | - Kenth‐Arne Hansson
- Department of Biosciences University of Oslo Oslo Norway
- Center for Integrative Neuroplasticity (CINPLA) University of Oslo Oslo Norway
| | - Andreas Solbrå
- Center for Integrative Neuroplasticity (CINPLA) University of Oslo Oslo Norway
- Department of Physics University of Oslo Oslo Norway
| | - Simen Tennøe
- Center for Integrative Neuroplasticity (CINPLA) University of Oslo Oslo Norway
- Department of Informatics University of Oslo Oslo Norway
| | - Fahri Saatcioglu
- Department of Biosciences University of Oslo Oslo Norway
- Institute of Cancer Genetics and Informatics Oslo University Hospital Oslo Norway
| | - Jo Christiansen Bruusgaard
- Department of Biosciences University of Oslo Oslo Norway
- Center for Integrative Neuroplasticity (CINPLA) University of Oslo Oslo Norway
- Department of Health Sciences Kristiania University College Oslo Norway
| | - Kristian Gundersen
- Department of Biosciences University of Oslo Oslo Norway
- Center for Integrative Neuroplasticity (CINPLA) University of Oslo Oslo Norway
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Schwartz LM. Skeletal Muscles Do Not Undergo Apoptosis During Either Atrophy or Programmed Cell Death-Revisiting the Myonuclear Domain Hypothesis. Front Physiol 2019; 9:1887. [PMID: 30740060 PMCID: PMC6356110 DOI: 10.3389/fphys.2018.01887] [Citation(s) in RCA: 44] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2018] [Accepted: 12/12/2018] [Indexed: 12/20/2022] Open
Abstract
Skeletal muscles are the largest cells in the body and are one of the few syncytial ones. There is a longstanding belief that a given nucleus controls a defined volume of cytoplasm, so when a muscle grows (hypertrophy) or shrinks (atrophy), the number of myonuclei change accordingly. This phenomenon is known as the “myonuclear domain hypothesis.” There is a general agreement that hypertrophy is accompanied by the addition of new nuclei from stem cells to help the muscles meet the enhanced synthetic demands of a larger cell. However, there is a considerable controversy regarding the fate of pre-existing nuclei during atrophy. Many researchers have reported that atrophy is accompanied by the dramatic loss of myonuclei via apoptosis. However, since there are many different non-muscle cell populations that reside within the tissue, these experiments cannot easily distinguish true myonuclei from those of neighboring mononuclear cells. Recently, two independent models, one from rodents and the other from insects, have demonstrated that nuclei are not lost from skeletal muscle fibers when they undergo either atrophy or programmed cell death. These and other data argue against the current interpretation of the myonuclear domain hypothesis and suggest that once a nucleus has been acquired by a muscle fiber it persists.
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Affiliation(s)
- Lawrence M Schwartz
- Department of Biology, Morrill Science Center, University of Massachusetts, Amherst, MA, United States
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Oliveira PFD, Iunes DH, Alves RS, Carvalho JMD, Menezes FDS, Carvalho LC. Effects of Exergaming in Cancer Related Fatigue in the Quality of Life and Electromyography of the Middle Deltoid of People with Cancer in Treatment: A Controlled Trial. Asian Pac J Cancer Prev 2018; 19:2591-2597. [PMID: 30256065 PMCID: PMC6249443 DOI: 10.22034/apjcp.2018.19.9.2591] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Objective: In the present study, we aimed to evaluate the effects an exergaming protocol for cancer patients who undergo or have already undergone cancer treatment. We sought to evaluate changes in cancer-related fatigue, function, and ability to perform daily activities, in addition to changes in the electromyographic pattern of the middle deltoid muscle. Methods: We conducted a controlled trial. Nineteen volunteers in the cancer group (aged 61 ± 9 years; body mass index28 ± 5) and 19 in the control group (aged 58 ± 8 years); body mass index 28 ± 4) participated in the study. They were evaluated by means of a sociodemographic and clinical questionnaire, the Functional Assessment of Chronic Therapy-Fatigue (FACIT-F) questionnaire, and surface electromyography in the deltoid muscle at three moments: before the beginning of the exergaming protocol, after 10 training sessions, and after 20 sessions. The protocol consisted of practicing exergaming using Xbox 360® (Microsoft, Redmond, USA) with Kinect®. The game “Your Shape Fitness Evolved” (Ubisoft, Rennes, France) was used. Results: Total FACIT-F scores, fatigue subscale scores, and median frequency values observed in the cancer group were lower than those in the control group. These values improved in relation to the initial evaluation in the cancer group after the practice of the exergaming protocol. Conclusion: The exergaming protocol used in this study was effective for reducing reported symptoms of fatigue, increasing perceived quality of life, and improving the pattern of deltoid muscle contraction in cancer patients.
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Affiliation(s)
- Paulo Furtado de Oliveira
- Motricity Science Institute, Federal University of Alfenas, 2600 Jovino Fernandes Sales Ave, Alfenas, Minas Gerais, Brazil.,Bioscience Program, Federal University of Alfenas, 2600 Jovino Fernandes Sales Ave, Alfenas, Minas Gerais, Brazil.
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Islam R, Yoon H, Shin HR, Bae HS, Kim BS, Yoon WJ, Woo KM, Baek JH, Lee YS, Ryoo HM. Peptidyl-prolyl cis-trans isomerase NIMA interacting 1 regulates skeletal muscle fusion through structural modification of Smad3 in the linker region. J Cell Physiol 2018; 233:9390-9403. [PMID: 30132832 PMCID: PMC6686165 DOI: 10.1002/jcp.26774] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2018] [Accepted: 04/27/2018] [Indexed: 02/07/2023]
Abstract
Myoblast fusion is critical for muscle growth, regeneration, and repair. We previously reported that the enzyme peptidyl‐prolyl cis–trans isomerase NIMA interacting 1 (Pin1) is involved in osteoclast fusion. The objective of this study was to investigate the possibility that Pin1 also inhibits myoblast fusion. Here, we show the increased number of nuclei in the Pin1+/− mice muscle fiber compared to that in wild‐type mice. Moreover, we show that low dose of the Pin1 inhibitor dipentamethylene thiuram monosulfide treatment caused enhanced fusion in C2C12 cells. The R‐Smads are well‐known mediators of muscle hypertrophy and hyperplasia as well as being substrates of Pin1. We found that Pin1 is crucial for maintaining the stability of Smad3 (homologues of the Drosophila protein, mothers against decapentaplegic (Mad) and the Caenorhabditis elegans protein Sma). Our results show that serine 204 within Smad3 is the key Pin1‐binding site during inhibition of myoblast fusion and that both the transforming growth factor‐β receptor and extracellular signal‐regulated kinase (ERK)‐mediated phosphorylation are required for the interaction of Pin1 with Smad3. These findings suggest that a precise level of Pin1 activity is essential for regulating myoblast fusion during myogenesis and muscle regeneration.
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Affiliation(s)
- Rabia Islam
- Department of Molecular Genetics, School of Dentistry and Dental Research Institute, Seoul National University, Seoul, Republic of Korea
| | - Heein Yoon
- Department of Molecular Genetics, School of Dentistry and Dental Research Institute, Seoul National University, Seoul, Republic of Korea
| | - Hye-Rim Shin
- Department of Molecular Genetics, School of Dentistry and Dental Research Institute, Seoul National University, Seoul, Republic of Korea
| | - Han-Sol Bae
- Department of Molecular Genetics, School of Dentistry and Dental Research Institute, Seoul National University, Seoul, Republic of Korea
| | - Bong-Soo Kim
- Department of Molecular Genetics, School of Dentistry and Dental Research Institute, Seoul National University, Seoul, Republic of Korea
| | - Won-Joon Yoon
- Department of Molecular Genetics, School of Dentistry and Dental Research Institute, Seoul National University, Seoul, Republic of Korea
| | - Kyung-Mi Woo
- Department of Molecular Genetics, School of Dentistry and Dental Research Institute, Seoul National University, Seoul, Republic of Korea
| | - Jeong-Hwa Baek
- Department of Molecular Genetics, School of Dentistry and Dental Research Institute, Seoul National University, Seoul, Republic of Korea
| | - Yun-Sil Lee
- Department of Molecular Genetics, School of Dentistry and Dental Research Institute, Seoul National University, Seoul, Republic of Korea
| | - Hyun-Mo Ryoo
- Department of Molecular Genetics, School of Dentistry and Dental Research Institute, Seoul National University, Seoul, Republic of Korea
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37
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Winje IM, Bengtsen M, Eftestøl E, Juvkam I, Bruusgaard JC, Gundersen K. Specific labelling of myonuclei by an antibody against pericentriolar material 1 on skeletal muscle tissue sections. Acta Physiol (Oxf) 2018; 223:e13034. [PMID: 29330928 DOI: 10.1111/apha.13034] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2017] [Revised: 01/05/2018] [Accepted: 01/08/2018] [Indexed: 01/11/2023]
Abstract
AIM Skeletal muscle is a heterogeneous tissue containing several different cell types, and only about 40%-50% of the cell nuclei within the tissue belong to myofibres. Existing technology, attempting to distinguish myonuclei from other nuclei at the light microscopy level, has led to controversies in our understanding of the basic cell biology of muscle plasticity. This study aims at demonstrating that an antibody against the protein pericentriolar material 1 (PCM1) can be used to reliably identify myonuclei on histological cross sections from humans, mice and rats. METHODS Cryosections were labelled with a polyclonal antibody against PCM1. The specificity of the labelling for myonuclei was verified using 3D reconstructions of confocal z-stacks triple-labelled for DNA, dystrophin and PCM1, and by co-localization with nuclear mCherry driven by the muscle-specific Alpha-Actin-1 promoter after viral transduction. RESULTS The PCM1 antibody specifically labelled all myonuclei, and myonuclei only, in cryosections of muscles from rats, mice and men. Nuclei in other cell types including satellite cells were not labelled. Both normal muscles and hypertrophic muscles after synergist ablation were investigated. CONCLUSION Pericentriolar material 1 can be used as a specific histological marker for myonuclei in skeletal muscle tissue without relying on counterstaining of other structures or cumbersome and subjective analysis of nuclear positioning.
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Affiliation(s)
- I M Winje
- Department of Biosciences, University of Oslo, Oslo, Norway
| | - M Bengtsen
- Department of Biosciences, University of Oslo, Oslo, Norway
| | - E Eftestøl
- Department of Biosciences, University of Oslo, Oslo, Norway
| | - I Juvkam
- Department of Biosciences, University of Oslo, Oslo, Norway
| | - J C Bruusgaard
- Department of Biosciences, University of Oslo, Oslo, Norway
- Department of Health Sciences, Kristiania University College, Oslo, Norway
| | - K Gundersen
- Department of Biosciences, University of Oslo, Oslo, Norway
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Preclinical characterization of the JAK/STAT inhibitor SGI-1252 on skeletal muscle function, morphology, and satellite cell content. PLoS One 2018; 13:e0198611. [PMID: 29897957 PMCID: PMC5999283 DOI: 10.1371/journal.pone.0198611] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2018] [Accepted: 05/22/2018] [Indexed: 01/20/2023] Open
Abstract
Background Recent studies have highlighted the JAK/STAT signaling pathway in the regulation of muscle satellite cell behavior. Herein we report preclinical studies designed to characterize the effects of a novel JAK/STAT inhibitor on plantar flexor skeletal muscle function, morphology, and satellite cell content. Methods The compound, SGI-1252, was administered orally (400mg/kg) in a 10% dextrose solution to wild type mice (n = 6) 3 times per week for 8 weeks. A control group (n = 6) received only the dextrose solution. Results SGI-1252 was well tolerated, as animals displayed similar weight gain over the 8-week treatment period. Following treatment, fatigue in the gastrocnemius-soleus-plantaris complex was greater in the SGI-1252 mice during a 300 second tetanic contraction bout (p = 0.035), though both the rate of fatigue and maximal force production were similar. SGI-1252 treated mice had increased type II myofiber cross-sectional area (1434.8 ± 225.4 vs 1754.7 ± 138.5 μm2), along with an increase in wet muscle mass (125.45 ± 5.46 vs 139.6 ± 12.34 mg, p = 0.032) of the gastrocnemius relative to vehicle treated mice. SGI-1252 treatment reduced gastrocnemius STAT3 phosphorylation 53% (94.79 ± 45.9 vs 44.5 ± 6.1 MFI) and significantly increased the concentration of Pax7+ satellite cells (2589.2 ± 105.5 vs 2859.4 ± 177.5 SC/mm3) in the gastrocnemius. SGI-1252 treatment suppressed MyoD (p = 0.013) and Myogenin (p<0.0001) expression in human primary myoblasts, resulting in reduced myogenic differentiation (p = 0.039). Conclusions Orally delivered SGI-1252 was well tolerated, attenuates skeletal muscle STAT3 activity, and increases satellite cell content in mouse gastrocnemius muscle, likely by inhibiting myogenic progression.
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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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40
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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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41
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White DP, Baumgarner BL, Watanabe WO, Alam MS, Kinsey ST. The effects of dietary β-guanidinopropionic acid on growth and muscle fiber development in juvenile red porgy, Pagrus pagrus. Comp Biochem Physiol B Biochem Mol Biol 2017; 216:48-58. [PMID: 29175483 DOI: 10.1016/j.cbpb.2017.11.010] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2017] [Revised: 11/10/2017] [Accepted: 11/17/2017] [Indexed: 02/07/2023]
Abstract
β-guanidinopropionic acid (β-GPA) has been used in mammalian models to reduce intracellular phosphocreatine (PCr) concentration, which in turn lowers the energetic state of cells. This leads to changes in signaling pathways that attempt to re-establish energetic homeostasis. Changes in those pathways elicit effects similar to those of exercise such as changes in body and muscle growth, metabolism, endurance and health. Generally, exercise effects are beneficial to fish health and aquaculture, but inducing exercise in fishes can be impractical. Therefore, this study evaluated the potential use of supplemental β-GPA to induce exercise-like effects in a rapidly growing juvenile teleost, the red porgy (Pagrus pagrus). We demonstrate for the first time that β-GPA can be transported into teleost muscle fibers and is phosphorylated, and that this perturbs the intracellular energetic state of the cells, although to a lesser degree than typically seen in mammals. β-GPA did not affect whole animal growth, nor did it influence skeletal muscle fiber size or myonuclear recruitment. There was, however, an increase in mitochondrial volume within myofibers in treated fish. GC/MS metabolomic analysis revealed shifts in amino acid composition of the musculature, putatively reflecting increases in connective tissue and decreases in protein synthesis that are associated with β-GPA treatment. These results suggest that β-GPA modestly affects fish muscle in a manner similar to that observed in mammals, and that β-GPA may have application to aquaculture by providing a more practical means of generating some of the beneficial effects of exercise in fishes.
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Affiliation(s)
- Dalon P White
- Department of Biology and Marine Biology, University of North Carolina Wilmington, Wilmington, NC 28403-5915, United States.
| | - Bradley L Baumgarner
- Division of Natural Sciences and Engineering, University of South Carolina Upstate, 800 University Way, Spartanburg, SC 29303, United States
| | - Wade O Watanabe
- Department of Biology and Marine Biology, University of North Carolina Wilmington, Wilmington, NC 28403-5915, United States; Center for Marine Science, University of North Carolina Wilmington, Wilmington, NC 28403-5928, United States
| | - Md Shah Alam
- Center for Marine Science, University of North Carolina Wilmington, Wilmington, NC 28403-5928, United States
| | - Stephen T Kinsey
- Department of Biology and Marine Biology, University of North Carolina Wilmington, Wilmington, NC 28403-5915, United States
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42
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Finnerty CC, McKenna CF, Cambias LA, Brightwell CR, Prasai A, Wang Y, El Ayadi A, Herndon DN, Suman OE, Fry CS. Inducible satellite cell depletion attenuates skeletal muscle regrowth following a scald-burn injury. J Physiol 2017; 595:6687-6701. [PMID: 28833130 PMCID: PMC5663820 DOI: 10.1113/jp274841] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2017] [Accepted: 08/15/2017] [Indexed: 12/20/2022] Open
Abstract
KEY POINTS Severe burns result in significant skeletal muscle cachexia that impedes recovery. Activity of satellite cells, skeletal muscle stem cells, is altered following a burn injury and likely hinders regrowth of muscle. Severe burn injury induces satellite cell proliferation and fusion into myofibres with greater activity in muscles proximal to the injury site. Conditional depletion of satellite cells attenuates recovery of myofibre area and volume following a scald burn injury in mice. Skeletal muscle regrowth following a burn injury requires satellite cell activity, underscoring the therapeutic potential of satellite cells in the prevention of prolonged frailty in burn survivors. ABSTRACT Severe burns result in profound skeletal muscle atrophy; persistent muscle atrophy and weakness are major complications that hamper recovery from burn injury. Many factors contribute to the erosion of muscle mass following burn trauma, and we have previously shown concurrent activation and apoptosis of muscle satellite cells following a burn injury in paediatric patients. To determine the necessity of satellite cells during muscle recovery following a burn injury, we utilized a genetically modified mouse model (Pax7CreER -DTA) that allows for the conditional depletion of satellite cells in skeletal muscle. Additionally, mice were provided 5-ethynyl-2'-deoxyuridine to determine satellite cell proliferation, activation and fusion. Juvenile satellite cell-wild-type (SC-WT) and satellite cell-depleted (SC-Dep) mice (8 weeks of age) were randomized to sham or burn injury consisting of a dorsal scald burn injury covering 30% of total body surface area. Both hindlimb and dorsal muscles were studied at 7, 14 and 21 days post-burn. SC-Dep mice had >93% depletion of satellite cells compared to SC-WT (P < 0.05). Burn injury induced robust atrophy in muscles located both proximal and distal to the injury site (∼30% decrease in fibre cross-sectional area, P < 0.05). Additionally, burn injury induced skeletal muscle regeneration, satellite cell proliferation and fusion. Depletion of satellite cells impaired post-burn recovery of both muscle fibre cross-sectional area and volume (P < 0.05). These findings support an integral role for satellite cells in the aetiology of lean tissue recovery following a severe burn injury.
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Affiliation(s)
- Celeste C. Finnerty
- Department of SurgeryUniversity of Texas Medical BranchGalvestonTXUSA
- Shriners Hospital for ChildrenGalvestonTXUSA
- Institute for Translational ScienceUniversity of Texas Medical BranchGalvestonTXUSA
| | - Colleen F. McKenna
- Department of Nutrition and MetabolismUniversity of Texas Medical BranchGalvestonTXUSA
| | - Lauren A. Cambias
- Department of Nutrition and MetabolismUniversity of Texas Medical BranchGalvestonTXUSA
| | - Camille R. Brightwell
- Division of Rehabilitation SciencesUniversity of Texas Medical Branch, GalvestonTXUSA
| | - Anesh Prasai
- Department of SurgeryUniversity of Texas Medical BranchGalvestonTXUSA
- Shriners Hospital for ChildrenGalvestonTXUSA
| | - Ye Wang
- Department of SurgeryUniversity of Texas Medical BranchGalvestonTXUSA
- Shriners Hospital for ChildrenGalvestonTXUSA
| | - Amina El Ayadi
- Department of SurgeryUniversity of Texas Medical BranchGalvestonTXUSA
- Shriners Hospital for ChildrenGalvestonTXUSA
| | - David N. Herndon
- Department of SurgeryUniversity of Texas Medical BranchGalvestonTXUSA
- Shriners Hospital for ChildrenGalvestonTXUSA
- Institute for Translational ScienceUniversity of Texas Medical BranchGalvestonTXUSA
| | - Oscar E. Suman
- Department of SurgeryUniversity of Texas Medical BranchGalvestonTXUSA
- Shriners Hospital for ChildrenGalvestonTXUSA
| | - Christopher S. Fry
- Shriners Hospital for ChildrenGalvestonTXUSA
- Institute for Translational ScienceUniversity of Texas Medical BranchGalvestonTXUSA
- Department of Nutrition and MetabolismUniversity of Texas Medical BranchGalvestonTXUSA
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43
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Wen Y, Murach KA, Vechetti IJ, Fry CS, Vickery C, Peterson CA, McCarthy JJ, Campbell KS. MyoVision: software for automated high-content analysis of skeletal muscle immunohistochemistry. J Appl Physiol (1985) 2017; 124:40-51. [PMID: 28982947 DOI: 10.1152/japplphysiol.00762.2017] [Citation(s) in RCA: 155] [Impact Index Per Article: 22.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Analysis of skeletal muscle cross sections is an important experimental technique in muscle biology. Many aspects of immunohistochemistry and fluorescence microscopy can now be automated, but most image quantification techniques still require extensive human input, slowing progress and introducing the possibility of user bias. MyoVision is a new software package that was developed to overcome these limitations. The software improves upon previously reported automatic techniques and analyzes images without requiring significant human input and correction. When compared with data derived by manual quantification, MyoVision achieves an accuracy of ≥94% for basic measurements such as fiber number, fiber type distribution, fiber cross-sectional area, and myonuclear number. Scientists can download the software free from www.MyoVision.org and use it to automate the analysis of their own experimental data. This will improve the efficiency and consistency of the analysis of muscle cross sections and help to reduce the burden of routine image quantification in muscle biology. NEW & NOTEWORTHY Scientists currently analyze images of immunofluorescently labeled skeletal muscle using time-consuming techniques that require sustained human supervision. As well as being inefficient, these techniques can increase variability in studies that quantify morphological adaptations of skeletal muscle at the cellular level. MyoVision is new software that overcomes these limitations by performing high-content analysis of muscle cross sections with minimal manual input. It is open source and freely available.
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Affiliation(s)
- Yuan Wen
- Department of Physiology, College of Medicine, University of Kentucky , Lexington, Kentucky.,Center for Muscle Biology, University of Kentucky , Lexington, Kentucky.,MD/PhD Program, College of Medicine, University of Kentucky , Lexington, Kentucky
| | - Kevin A Murach
- Center for Muscle Biology, University of Kentucky , Lexington, Kentucky
| | - Ivan J Vechetti
- Department of Physiology, College of Medicine, University of Kentucky , Lexington, Kentucky.,Center for Muscle Biology, University of Kentucky , Lexington, Kentucky
| | - Christopher S Fry
- Department of Nutrition and Metabolism, Division of Rehabilitation Sciences, and Sealy Center on Aging, University of Texas Medical Branch , Galveston, Texas
| | - Chase Vickery
- MSTC Program, Paul Laurence Dunbar High School , Lexington, Kentucky
| | - Charlotte A Peterson
- 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
- Department of Physiology, College of Medicine, University of Kentucky , Lexington, Kentucky.,Center for Muscle Biology, University of Kentucky , Lexington, Kentucky
| | - Kenneth S Campbell
- Department of Physiology, College of Medicine, University of Kentucky , Lexington, Kentucky.,Center for Muscle Biology, University of Kentucky , Lexington, Kentucky.,Division of Cardiovascular Medicine, College of Medicine, University of Kentucky , Lexington, Kentucky
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44
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Egner IM, Bruusgaard JC, Gundersen K. Satellite cell depletion prevents fiber hypertrophy in skeletal muscle. Development 2017; 143:2898-906. [PMID: 27531949 DOI: 10.1242/dev.134411] [Citation(s) in RCA: 142] [Impact Index Per Article: 20.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2015] [Accepted: 06/28/2016] [Indexed: 12/18/2022]
Abstract
The largest mammalian cells are the muscle fibers, and they have multiple nuclei to support their large cytoplasmic volumes. During hypertrophic growth, new myonuclei are recruited from satellite stem cells into the fiber syncytia, but it was recently suggested that such recruitment is not obligatory: overload hypertrophy after synergist ablation of the plantaris muscle appeared normal in transgenic mice in which most of the satellite cells were abolished. When we essentially repeated these experiments analyzing the muscles by immunohistochemistry and in vivo and ex vivo imaging, we found that overload hypertrophy was prevented in the satellite cell-deficient mice, in both the plantaris and the extensor digitorum longus muscles. We attribute the previous findings to a reliance on muscle mass as a proxy for fiber hypertrophy, and to the inclusion of a significant number of regenerating fibers in the analysis. We discuss that there is currently no model in which functional, sustainable hypertrophy has been unequivocally demonstrated in the absence of satellite cells; an exception is re-growth, which can occur using previously recruited myonuclei without addition of new myonuclei.
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Affiliation(s)
- Ingrid M Egner
- Department of Biosciences, University of Oslo, Blindern, Oslo N-0316, Norway
| | - Jo C Bruusgaard
- Department of Biosciences, University of Oslo, Blindern, Oslo N-0316, Norway Department of Health Sciences, Kristiania University College, P.O. Box 1190, Sentrum, Oslo N-0107, Norway
| | - Kristian Gundersen
- Department of Biosciences, University of Oslo, Blindern, Oslo N-0316, Norway
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45
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Farup J, Torcinaro A, Madaro L. Skeletal muscle stem cell defects in burn-induced cachexia. J Physiol 2016; 594:7153-7154. [PMID: 27976402 DOI: 10.1113/jp273095] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Affiliation(s)
- Jean Farup
- Research Laboratory for Biochemical Pathology, Department for Clinical Medicine, Aarhus University, Aarhus, Denmark
| | - Alessio Torcinaro
- IRCCS Fondazione Santa Lucia, Rome, Italy.,Institute of Cell Biology and Neurology (IBCN), National Council of Research (CNR), Rome, Italy
| | - Luca Madaro
- IRCCS Fondazione Santa Lucia, Rome, Italy.,Institute of Cell Biology and Neurology (IBCN), National Council of Research (CNR), Rome, Italy
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46
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Itoh Y, Murakami T, Mori T, Agata N, Kimura N, Inoue-Miyazu M, Hayakawa K, Hirano T, Sokabe M, Kawakami K. Training at non-damaging intensities facilitates recovery from muscle atrophy. Muscle Nerve 2016; 55:243-253. [PMID: 27301985 DOI: 10.1002/mus.25218] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/09/2016] [Indexed: 11/07/2022]
Abstract
INTRODUCTION Resistance training promotes recovery from muscle atrophy, but optimum training programs have not been established. We aimed to determine the optimum training intensity for muscle atrophy. METHODS Mice recovering from atrophied muscles after 2 weeks of tail suspension underwent repeated isometric training with varying joint torques 50 times per day. RESULTS Muscle recovery assessed by maximal isometric contraction and myofiber cross-sectional areas (CSAs) were facilitated at 40% and 60% maximum contraction strength (MC), but at not at 10% and 90% MC. At 60% and 90% MC, damaged and contained smaller diameter fibers were observed. Activation of myogenic satellite cells and a marked increase in myonuclei were observed at 40%, 60%, and 90% MC. CONCLUSIONS The increases in myofiber CSAs were likely caused by increased myonuclei formed through fusion of resistance-induced myofibers with myogenic satellite cells. These data indicate that resistance training without muscle damage facilitates efficient recovery from atrophy. Muscle Nerve 55: 243-253, 2017.
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Affiliation(s)
- Yuta Itoh
- Physical and Occupational Therapy Program, Nagoya University Graduate School of Medicine, Nagoya, Japan
- Faculty of Rehabilitation Science, Nagoya Gakuin University, Seto, Japan
| | - Taro Murakami
- Faculty of Wellness, Shigakkan University, Ohbu, Japan
| | - Tomohiro Mori
- Physical and Occupational Therapy Program, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Nobuhide Agata
- Physical and Occupational Therapy Program, Nagoya University Graduate School of Medicine, Nagoya, Japan
- Faculty of Health and Medical Sciences, Tokoha University, Hamamatsu, Japan
| | - Nahoko Kimura
- Aiche Medical College for Physical and Occupational Therapy, Kiyosu, Japan
| | | | - Kimihide Hayakawa
- Mechanobiology Laboratory, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Takayuki Hirano
- Faculty of Rehabilitation Science, Nagoya Gakuin University, Seto, Japan
| | - Masahiro Sokabe
- Mechanobiology Laboratory, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Keisuke Kawakami
- Physical and Occupational Therapy Program, Nagoya University Graduate School of Medicine, Nagoya, Japan
- Faculty of Welfare and Health Sciences, Oita University, Dannoharu 700, Oita City, 870-1192, Japan
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Gundersen K. Muscle memory and a new cellular model for muscle atrophy and hypertrophy. ACTA ACUST UNITED AC 2016; 219:235-42. [PMID: 26792335 DOI: 10.1242/jeb.124495] [Citation(s) in RCA: 92] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Memory is a process in which information is encoded, stored, and retrieved. For vertebrates, the modern view has been that it occurs only in the brain. This review describes a cellular memory in skeletal muscle in which hypertrophy is 'remembered' such that a fibre that has previously been large, but subsequently lost its mass, can regain mass faster than naive fibres. A new cell biological model based on the literature, with the most reliable methods for identifying myonuclei, can explain this phenomenon. According to this model, previously untrained fibres recruit myonuclei from activated satellite cells before hypertrophic growth. Even if subsequently subjected to grave atrophy, the higher number of myonuclei is retained, and the myonuclei seem to be protected against the elevated apoptotic activity observed in atrophying muscle tissue. Fibres that have acquired a higher number of myonuclei grow faster when subjected to overload exercise, thus the nuclei represent a functionally important 'memory' of previous strength. This memory might be very long lasting in humans, as myonuclei are stable for at least 15 years and might even be permanent. However, myonuclei are harder to recruit in the elderly, and if the long-lasting muscle memory also exists in humans, one should consider early strength training as a public health advice. In addition, myonuclei are recruited during steroid use and encode a muscle memory, at least in rodents. Thus, extending the exclusion time for doping offenders should be considered.
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Affiliation(s)
- Kristian Gundersen
- Department of Biosciences, University of Oslo, Blindernveien 31, Oslo N0316, Norway
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Brocca L, Longa E, Cannavino J, Seynnes O, de Vito G, McPhee J, Narici M, Pellegrino MA, Bottinelli R. Human skeletal muscle fibre contractile properties and proteomic profile: adaptations to 3 weeks of unilateral lower limb suspension and active recovery. J Physiol 2016; 593:5361-85. [PMID: 26369674 DOI: 10.1113/jp271188] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2015] [Accepted: 09/04/2015] [Indexed: 01/08/2023] Open
Abstract
KEY POINTS It is generally assumed that muscle fibres go through atrophy following disuse with a loss of specific force and an increase in unloaded shortening velocity. However, the underlying mechanisms remain to be clarified. Most studies have focused on events taking place during the development of disuse, whereas the subsequent recovery phase, which is equally important, has received little attention. Our findings support the hypotheses that the specific force of muscle fibres decreased following unilateral lower limb suspension (ULLS) and returned to normal after 3 weeks of active recovery as a result of a loss and recovery of myosin and actin content. Furthermore, muscle fibres went through extensive qualitative changes in muscle protein pattern following ULLS, and these were reversed by active recovery. Resistance training was very effective in restoring both muscle mass and qualitative muscle changes, indicating that long-term ULLS did not prevent the positive effect of exercise on human muscle. ABSTRACT Following disuse, muscle fibre function goes through adaptations such as a loss of specific force (PO /CSA) and an increase in unloaded shortening velocity, which could be a result of both quantitative changes (i.e. atrophy) and qualitative changes in protein pattern. The underlying mechanisms remain to be clarified. In addition, little is known about the recovery of muscle mass and strength following disuse. In the present study, we report an extensive dataset describing, in detail,the functional and protein content adaptations of skeletal muscle in response to both disuse and re-training. Eight young healthy subjects were subjected to 3 weeks of unilateral lower limb suspension (ULLS), a widely used human model of disuse skeletal muscle atrophy. Needle biopsies samples were taken from the vastus lateralis muscle Pre-ULLS, Post-ULLS and after 3 weeks of recovery during which heavy resistance training was performed. After disuse, cross-sectional area (CSA), PO /CSA and myosin concentration (MC) decreased in both type 1 and 2A skinned muscle fibres. After recovery, CSA and MC returned to levels comparable to those observed before disuse, whereas Po/CSA and unloaded shortening velocity reached a higher level. Myosin heavy chain isoform composition of muscle samples did not differ among the experimental groups. To study the mechanisms underlying such adaptations, a two-dimensional proteomic analysis was performed. ULLS induced a reduction of myofibrillar, metabolic (glycolytic and oxidative) and anti-oxidant defence system protein content. Resistance training was very effective in counteracting ULLS-induced alterations, indicating that long-term ULLS did not prevent the positive effect of exercise on human muscle.
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Affiliation(s)
- Lorenza Brocca
- Department of Molecular Medicine, University of Pavia, Pavia, Italy.,Interuniversity Institute of Myology, University of Pavia, Pavia, Italy
| | - Emanuela Longa
- Department of Molecular Medicine, University of Pavia, Pavia, Italy.,Interdipartimental Centre for Biology and Sport Medicine, University of Pavia, Pavia, Italy
| | | | - Olivier Seynnes
- Institute for Biomedical Research into Human Movement and Health, Manchester Metropolitan University, Manchester, UK.,Norwegian School of Sport Sciences, Oslo, Norway
| | - Giuseppe de Vito
- UCD Institute for Sport and Health, University College Dublin, Dublin, Ireland
| | - Jamie McPhee
- Institute for Biomedical Research into Human Movement and Health, Manchester Metropolitan University, Manchester, UK
| | - Marco Narici
- Institute for Biomedical Research into Human Movement and Health, Manchester Metropolitan University, Manchester, UK.,School of Graduate Entry to Medicine and Health, Division of Clinical Physiology, University of Nottingham, Derby, UK
| | - Maria Antonietta Pellegrino
- Department of Molecular Medicine, University of Pavia, Pavia, Italy.,Interdipartimental Centre for Biology and Sport Medicine, University of Pavia, Pavia, Italy.,Interuniversity Institute of Myology, University of Pavia, Pavia, Italy
| | - Roberto Bottinelli
- Department of Molecular Medicine, University of Pavia, Pavia, Italy.,Fondazione Salvatore Maugeri (IRCCS), Scientific Institute of Pavia, Pavia, Italy
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Reduced Appendicular Lean Body Mass, Muscle Strength, and Size of Type II Muscle Fibers in Patients with Spondyloarthritis versus Healthy Controls: A Cross-Sectional Study. ScientificWorldJournal 2016; 2016:6507692. [PMID: 27672678 PMCID: PMC5031855 DOI: 10.1155/2016/6507692] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2016] [Revised: 07/17/2016] [Accepted: 08/09/2016] [Indexed: 01/08/2023] Open
Abstract
Introduction. The purpose of this study was to investigate body composition, muscle function, and muscle morphology in patients with spondyloarthritis (SpA). Methods. Ten male SpA patients (mean ± SD age 39 ± 4.1 years) were compared with ten healthy controls matched for sex, age, body mass index, and self-reported level of physical exercise. Body composition was measured by dual energy X-ray absorptiometry. Musculus quadriceps femoris (QF) strength was assessed by maximal isometric contractions prior to test of muscular endurance. Magnetic resonance imaging of QF was used to measure muscle size and calculate specific muscle strength. Percutaneous needle biopsy samples were taken from m. vastus lateralis. Results. SpA patients presented with significantly lower appendicular lean body mass (LBM) (p = 0.02), but there was no difference in bone mineral density, fat mass, or total LBM. Absolute QF strength was significantly lower in SpA patients (p = 0.03) with a parallel trend for specific strength (p = 0.08). Biopsy samples from the SpA patients revealed significantly smaller cross-sectional area (CSA) of type II muscle fibers (p = 0.04), but no difference in CSA type I fibers. Conclusions. Results indicate that the presence of SpA disease is associated with reduced appendicular LBM, muscle strength, and type II fiber CSA.
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50
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Schwartz LM, Brown C, McLaughlin K, Smith W, Bigelow C. The myonuclear domain is not maintained in skeletal muscle during either atrophy or programmed cell death. Am J Physiol Cell Physiol 2016; 311:C607-C615. [PMID: 27558160 DOI: 10.1152/ajpcell.00176.2016] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2016] [Accepted: 08/17/2016] [Indexed: 11/22/2022]
Abstract
Skeletal muscle mass can increase during hypertrophy or decline dramatically in response to normal or pathological signals that trigger atrophy. Many reports have documented that the number of nuclei within these cells is also plastic. It has been proposed that a yet-to-be-defined regulatory mechanism functions to maintain a relatively stable relationship between the cytoplasmic volume and nuclear number within the cell, a phenomenon known as the "myonuclear domain" hypothesis. While it is accepted that hypertrophy is typically associated with the addition of new nuclei to the muscle fiber from stem cells such as satellite cells, the loss of myonuclei during atrophy has been controversial. The intersegmental muscles from the tobacco hawkmoth Manduca sexta are composed of giant syncytial cells that undergo sequential developmental programs of atrophy and programmed cell death at the end of metamorphosis. Since the intersegmental muscles lack satellite cells or regenerative capacity, the tissue is not "contaminated" by these nonmuscle nuclei. Consequently, we monitored muscle mass, cross-sectional area, nuclear number, and cellular DNA content during atrophy and the early phases of cell death. Despite a ∼75-80% decline in muscle mass and cross-sectional area during the period under investigation, there were no reductions in nuclear number or DNA content, and the myonuclear domain was reduced by ∼85%. These data suggest that the myonuclear domain is not an intrinsic property of skeletal muscle and that nuclei persist through atrophy and programmed cell death.
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Affiliation(s)
| | - Christine Brown
- Department of Biology, University of Massachusetts, Amherst, Massachusetts
| | - Kevin McLaughlin
- Department of Biology, University of Massachusetts, Amherst, Massachusetts
| | - Wendy Smith
- Department of Biology, Northeastern University, Boston, Massachusetts; and
| | - Carol Bigelow
- Department of Biostatistics and Epidemiology, University of Massachusetts, Amherst, Massachusetts
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