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Millward DJ. Post-natal muscle growth and protein turnover: a narrative review of current understanding. Nutr Res Rev 2024; 37:141-168. [PMID: 37395180 DOI: 10.1017/s0954422423000124] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/04/2023]
Abstract
A model explaining the dietary-protein-driven post-natal skeletal muscle growth and protein turnover in the rat is updated, and the mechanisms involved are described, in this narrative review. Dietary protein controls both bone length and muscle growth, which are interrelated through mechanotransduction mechanisms with muscle growth induced both from stretching subsequent to bone length growth and from internal work against gravity. This induces satellite cell activation, myogenesis and remodelling of the extracellular matrix, establishing a growth capacity for myofibre length and cross-sectional area. Protein deposition within this capacity is enabled by adequate dietary protein and other key nutrients. After briefly reviewing the experimental animal origins of the growth model, key concepts and processes important for growth are reviewed. These include the growth in number and size of the myonuclear domain, satellite cell activity during post-natal development and the autocrine/paracrine action of IGF-1. Regulatory and signalling pathways reviewed include developmental mechanotransduction, signalling through the insulin/IGF-1-PI3K-Akt and the Ras-MAPK pathways in the myofibre and during mechanotransduction of satellite cells. Likely pathways activated by maximal-intensity muscle contractions are highlighted and the regulation of the capacity for protein synthesis in terms of ribosome assembly and the translational regulation of 5-TOPmRNA classes by mTORC1 and LARP1 are discussed. Evidence for and potential mechanisms by which volume limitation of muscle growth can occur which would limit protein deposition within the myofibre are reviewed. An understanding of how muscle growth is achieved allows better nutritional management of its growth in health and disease.
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Affiliation(s)
- D Joe Millward
- Department of Nutritional Sciences, School of Biosciences & Medicine, Faculty of Health and Medical Sciences, University of Surrey, Guildford, UK
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2
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Battey E, Levy Y, Pollock RD, Pugh JN, Close GL, Kalakoutis M, Lazarus NR, Harridge SDR, Ochala J, Stroud MJ. Muscle fibre size and myonuclear positioning in trained and aged humans. Exp Physiol 2024; 109:549-561. [PMID: 38461483 PMCID: PMC10988734 DOI: 10.1113/ep091567] [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: 10/04/2023] [Accepted: 02/05/2024] [Indexed: 03/12/2024]
Abstract
Changes in myonuclear architecture and positioning are associated with exercise adaptations and ageing. However, data on the positioning and number of myonuclei following exercise are inconsistent. Additionally, whether myonuclear domains (MNDs; i.e., the theoretical volume of cytoplasm within which a myonucleus is responsible for transcribing DNA) and myonuclear positioning are altered with age remains unclear. The aim of this investigation was to investigate relationships between age and activity status and myonuclear domains and positioning. Vastus lateralis muscle biopsies from younger endurance-trained (YT) and older endurance-trained (OT) individuals were compared with age-matched untrained counterparts (YU and OU; OU samples were acquired during surgical operation). Serial, optical z-slices were acquired throughout isolated muscle fibres and analysed to give three-dimensional coordinates for myonuclei and muscle fibre dimensions. The mean cross-sectional area (CSA) of muscle fibres from OU individuals was 33%-53% smaller compared with the other groups. The number of nuclei relative to fibre CSA was 90% greater in OU compared with YU muscle fibres. Additionally, scaling of MND volume with fibre size was altered in older untrained individuals. The myonuclear arrangement, in contrast, was similar across groups. Fibre CSA and most myonuclear parameters were significantly associated with age in untrained individuals, but not in trained individuals. These data indicate that regular endurance exercise throughout the lifespan might better preserve the size of muscle fibres in older age and maintain the relationship between fibre size and MND volumes. Inactivity, however, might result in reduced muscle fibre size and altered myonuclear parameters.
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Affiliation(s)
- Edmund Battey
- Centre for Human & Applied Physiological Sciences, Faculty of Life Sciences & MedicineKing's College LondonLondonUK
- British Heart Foundation Centre of Research Excellence, School of Cardiovascular Medicine and SciencesKing's College LondonLondonUK
- Department of Biomedical Sciences, Faculty of Medical and Health SciencesUniversity of CopenhagenCopenhagenDenmark
| | - Yotam Levy
- Centre for Human & Applied Physiological Sciences, Faculty of Life Sciences & MedicineKing's College LondonLondonUK
| | - Ross D. Pollock
- Centre for Human & Applied Physiological Sciences, Faculty of Life Sciences & MedicineKing's College LondonLondonUK
| | - Jamie N. Pugh
- School of Sport and Exercise Sciences, Tom Reilly Building, Byrom StreetLiverpool John Moores UniversityLiverpoolUK
| | - Graeme L. Close
- School of Sport and Exercise Sciences, Tom Reilly Building, Byrom StreetLiverpool John Moores UniversityLiverpoolUK
| | - Michaeljohn Kalakoutis
- Centre for Human & Applied Physiological Sciences, Faculty of Life Sciences & MedicineKing's College LondonLondonUK
- Randall Centre for Cell and Molecular Biophysics, Faculty of Life Sciences & MedicineKing's College LondonLondonUK
| | - Norman R. Lazarus
- Centre for Human & Applied Physiological Sciences, Faculty of Life Sciences & MedicineKing's College LondonLondonUK
| | - Stephen D. R. Harridge
- Centre for Human & Applied Physiological Sciences, Faculty of Life Sciences & MedicineKing's College LondonLondonUK
| | - Julien Ochala
- Centre for Human & Applied Physiological Sciences, Faculty of Life Sciences & MedicineKing's College LondonLondonUK
- Department of Biomedical Sciences, Faculty of Medical and Health SciencesUniversity of CopenhagenCopenhagenDenmark
| | - Matthew J. Stroud
- British Heart Foundation Centre of Research Excellence, School of Cardiovascular Medicine and SciencesKing's College LondonLondonUK
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3
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Roberts MD, McCarthy JJ, Hornberger TA, Phillips SM, Mackey AL, Nader GA, Boppart MD, Kavazis AN, Reidy PT, Ogasawara R, Libardi CA, Ugrinowitsch C, Booth FW, Esser KA. Mechanisms of mechanical overload-induced skeletal muscle hypertrophy: current understanding and future directions. Physiol Rev 2023; 103:2679-2757. [PMID: 37382939 PMCID: PMC10625844 DOI: 10.1152/physrev.00039.2022] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2023] [Revised: 06/12/2023] [Accepted: 06/21/2023] [Indexed: 06/30/2023] Open
Abstract
Mechanisms underlying mechanical overload-induced skeletal muscle hypertrophy have been extensively researched since the landmark report by Morpurgo (1897) of "work-induced hypertrophy" in dogs that were treadmill trained. Much of the preclinical rodent and human resistance training research to date supports that involved mechanisms include enhanced mammalian/mechanistic target of rapamycin complex 1 (mTORC1) signaling, an expansion in translational capacity through ribosome biogenesis, increased satellite cell abundance and myonuclear accretion, and postexercise elevations in muscle protein synthesis rates. However, several lines of past and emerging evidence suggest that additional mechanisms that feed into or are independent of these processes are also involved. This review first provides a historical account of how mechanistic research into skeletal muscle hypertrophy has progressed. A comprehensive list of mechanisms associated with skeletal muscle hypertrophy is then outlined, and areas of disagreement involving these mechanisms are presented. Finally, future research directions involving many of the discussed mechanisms are proposed.
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Affiliation(s)
- Michael D Roberts
- School of Kinesiology, Auburn University, Auburn, Alabama, United States
| | - John J McCarthy
- Department of Physiology, College of Medicine, University of Kentucky, Lexington, Kentucky, United States
| | - Troy A Hornberger
- Department of Comparative Biosciences, University of Wisconsin-Madison, Madison, Wisconsin, United States
| | - Stuart M Phillips
- Department of Kinesiology, McMaster University, Hamilton, Ontario, Canada
| | - Abigail L Mackey
- Institute of Sports Medicine Copenhagen, Department of Orthopedic Surgery, Copenhagen University Hospital-Bispebjerg and Frederiksberg, and Department of Clinical Medicine, University of Copenhagen, Copenhagen, Denmark
| | - Gustavo A Nader
- Department of Kinesiology and Huck Institutes of the Life Sciences, The Pennsylvania State University, University Park, Pennsylvania, United States
| | - Marni D Boppart
- Department of Kinesiology and Community Health, University of Illinois at Urbana-Champaign, Urbana, Illinois, United States
| | - Andreas N Kavazis
- School of Kinesiology, Auburn University, Auburn, Alabama, United States
| | - Paul T Reidy
- Department of Kinesiology, Nutrition and Health, Miami University, Oxford, Ohio, United States
| | - Riki Ogasawara
- Healthy Food Science Research Group, Cellular and Molecular Biotechnology Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Japan
| | - Cleiton A Libardi
- MUSCULAB-Laboratory of Neuromuscular Adaptations to Resistance Training, Department of Physical Education, Federal University of São Carlos, São Carlos, Brazil
| | - Carlos Ugrinowitsch
- School of Physical Education and Sport, University of São Paulo, São Paulo, Brazil
| | - Frank W Booth
- Department of Biomedical Sciences, University of Missouri, Columbia, Missouri, United States
| | - Karyn A Esser
- Department of Physiology and Aging, College of Medicine, University of Florida, Gainesville, Florida, United States
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Hatton IA, Galbraith ED, Merleau NSC, Miettinen TP, Smith BM, Shander JA. The human cell count and size distribution. Proc Natl Acad Sci U S A 2023; 120:e2303077120. [PMID: 37722043 PMCID: PMC10523466 DOI: 10.1073/pnas.2303077120] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2023] [Accepted: 07/24/2023] [Indexed: 09/20/2023] Open
Abstract
Cell size and cell count are adaptively regulated and intimately linked to growth and function. Yet, despite their widespread relevance, the relation between cell size and count has never been formally examined over the whole human body. Here, we compile a comprehensive dataset of cell size and count over all major cell types, with data drawn from >1,500 published sources. We consider the body of a representative male (70 kg), which allows further estimates of a female (60 kg) and 10-y-old child (32 kg). We build a hierarchical interface for the cellular organization of the body, giving easy access to data, methods, and sources (https://humancelltreemap.mis.mpg.de/). In total, we estimate total body counts of ≈36 trillion cells in the male, ≈28 trillion in the female, and ≈17 trillion in the child. These data reveal a surprising inverse relation between cell size and count, implying a trade-off between these variables, such that all cells within a given logarithmic size class contribute an equal fraction to the body's total cellular biomass. We also find that the coefficient of variation is approximately independent of mean cell size, implying the existence of cell-size regulation across cell types. Our data serve to establish a holistic quantitative framework for the cells of the human body, and highlight large-scale patterns in cell biology.
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Affiliation(s)
- Ian A. Hatton
- Max Planck Institute for Mathematics in the Sciences, Leipzig04103, Germany
- Department of Earth and Planetary Sciences, McGill University, Montreal, QuebecH3A 0E8, Canada
| | - Eric D. Galbraith
- Department of Earth and Planetary Sciences, McGill University, Montreal, QuebecH3A 0E8, Canada
- ICREA, Barcelona08010, Spain
| | - Nono S. C. Merleau
- Max Planck Institute for Mathematics in the Sciences, Leipzig04103, Germany
- Center for Scalable Data Analytics and Artificial Intelligence, University of Leipzig, D-04105Leipzig, Germany
| | - Teemu P. Miettinen
- Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, MA02139
| | - Benjamin McDonald Smith
- Department of Medicine, McGill University Health Centre Research Institute, Montreal, QuebecH4A 3S5, Canada
- Department of Medicine, Columbia University Medical Center, New York, NY10032
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Sun C, Swoboda CO, Petrany MJ, Parameswaran S, VonHandorf A, Weirauch MT, Lepper C, Millay DP. Lineage tracing of newly accrued nuclei in skeletal myofibers uncovers distinct transcripts and interplay between nuclear populations. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.08.24.554609. [PMID: 37662191 PMCID: PMC10473681 DOI: 10.1101/2023.08.24.554609] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/05/2023]
Abstract
Multinucleated skeletal muscle cells have an obligatory need to acquire additional nuclei through fusion with activated skeletal muscle stem cells when responding to both developmental and adaptive growth stimuli. A fundamental question in skeletal muscle biology has been the reason underlying this need for new nuclei in syncytial cells that already harbor hundreds of nuclei. To begin to answer this long-standing question, we utilized nuclear RNA-sequencing approaches and developed a lineage tracing strategy capable of defining the transcriptional state of recently fused nuclei and distinguishing this state from that of pre-existing nuclei. Our findings reveal the presence of conserved markers of newly fused nuclei both during development and after a hypertrophic stimulus in the adult. However, newly fused nuclei also exhibit divergent gene expression that is determined by the myogenic environment to which they fuse. Moreover, accrual of new nuclei through fusion is required for nuclei already resident in adult myofibers to mount a normal transcriptional response to a load-inducing stimulus. We propose a model of mutual regulation in the control of skeletal muscle development and adaptations, where newly fused and pre-existing myonuclear populations influence each other to maintain optimal functional growth.
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Affiliation(s)
- Chengyi Sun
- Division of Molecular Cardiovascular Biology, Cincinnati Children’s Hospital Medical Center, Cincinnati, OH, USA
| | - Casey O. Swoboda
- Division of Molecular Cardiovascular Biology, Cincinnati Children’s Hospital Medical Center, Cincinnati, OH, USA
- Division of Biomedical Informatics, Cincinnati Children’s Hospital Medical Center, Cincinnati, OH, USA
| | - Michael J. Petrany
- Division of Molecular Cardiovascular Biology, Cincinnati Children’s Hospital Medical Center, Cincinnati, OH, USA
| | - Sreeja Parameswaran
- Division of Human Genetics, Center for Autoimmune Genetics and Etiology (CAGE), Cincinnati Children’s Hospital Medical Center, Cincinnati, OH, USA
| | - Andrew VonHandorf
- Division of Human Genetics, Center for Autoimmune Genetics and Etiology (CAGE), Cincinnati Children’s Hospital Medical Center, Cincinnati, OH, USA
| | - Matthew T. Weirauch
- Division of Biomedical Informatics, Cincinnati Children’s Hospital Medical Center, Cincinnati, OH, USA
- Division of Human Genetics, Center for Autoimmune Genetics and Etiology (CAGE), Cincinnati Children’s Hospital Medical Center, Cincinnati, OH, USA
- Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, OH, USA
| | - Christoph Lepper
- Department of Physiology & Cell Biology, College of Medicine, The Ohio State University, Columbus, OH, USA
| | - Douglas P. Millay
- Division of Molecular Cardiovascular Biology, Cincinnati Children’s Hospital Medical Center, Cincinnati, OH, USA
- Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, OH, USA
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6
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Esteves M, Duarte M, Oliveira PA, Gil da Costa RM, Monteiro MP, Duarte JA. SKELETAL MUSCLE SENSITIVITY TO WASTING INDUCED BY UROTHELIAL CARCINOMA. Exp Oncol 2023; 45:107-119. [PMID: 37417276 DOI: 10.15407/exp-oncology.2023.01.107] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2023] [Indexed: 07/08/2023]
Abstract
BACKGROUND Skeletal muscle wasting is a common phenotypic feature of several types of cancer, and it is associated with functional impairment, respiratory complications, and fatigue. However, equivocal evidence remains regarding the impact of cancer-induced muscle wasting on the different fiber types. AIM The aim of this study was to investigate the impact of urothelial carcinoma induced in mice on the histomorphometric features and collagen deposition in different skeletal muscles. MATERIALS AND METHODS Thirteen ICR (CD1) male mice were randomly assigned into two groups: exposed to 0.05% N-butyl-N-(4-hydroxybutyl) nitrosamine (BBN) in drinking water for 12 weeks, plus 8 weeks of tap water (BBN, n = 8) or with access to tap water for 20 weeks (CONT, n = 5). Tibialis anterior, soleus, and diaphragm muscles were collected from all animals. For cross-sectional area and myonuclear domain analysis, muscle sections were stained with hematoxylin and eosin, and for collagen deposition assessment, muscle sections were stained with picrosirius red. RESULTS All animals from the BBN group developed urothelial preneoplastic and neoplastic lesions, and the tibialis anterior from these animals presented a reduced cross-sectional area (p < 0.001), with a decreased proportion of fibers with a higher cross-sectional area, increased collagen deposition (p = 0.017), and higher myonuclear domain (p = 0.031). BBN mice also showed a higher myonuclear domain in the diaphragm (p = 0.015). CONCLUSION Urothelial carcinoma induced muscle wasting of the tibialis anterior, expressed by a decreased cross-sectional area, higher infiltration of fibrotic tissue, and increased myonuclear domain, which also increased in the diaphragm, suggesting that fast glycolytic muscle fibers are more susceptible to be affected by cancer development.
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Affiliation(s)
- M Esteves
- FP-I3ID, FP-BHS, Escola Superior de Saúde Fernando Pessoa, Porto 4200-450, Portugal
- Research Center in Physical Activity, Health and Leisure (CIAFEL), Faculty of Sport, University of Porto, 4200-450 Porto, Portugal
| | - M Duarte
- Research Center in Physical Activity, Health and Leisure (CIAFEL), Faculty of Sport, University of Porto, 4200-450 Porto, Portugal
| | - P A Oliveira
- Institute for Innovation, Capacity Building and Sustainability of Agri-food Production (Inov4Agro), Centre for Research and Technology of Agro-Environmental and Biological Sciences (CITAB): Clinical Academic Centre, Vila Real, Portugal
- Department of Veterinary Sciences, University of Trás-os-Montes and Alto Douro, Vila Real, Portugal
| | - R M Gil da Costa
- Institute for Innovation, Capacity Building and Sustainability of Agri-food Production (Inov4Agro), Centre for Research and Technology of Agro-Environmental and Biological Sciences (CITAB): Clinical Academic Centre, Vila Real, Portugal
- Postgraduate Programme in Adult Health (PPGSAD), Federal University of Maranhão (UFMA), São Luís, Brazil
- Molecular Oncology and Viral Pathology Group, Research Center of IPO Porto (CI-IPOP)/RISE@CI-IPOP (Health Research Network), Portuguese Oncology Institute of Porto (IPO Porto), Porto Comprehensive Cancer Center (Porto.CCC), 4200-072 Porto, Portugal
- LEPABE - Laboratory for Process Engineering, Environment, Biotechnology and Energy, Faculty of Engineering, University of Porto, Rua Dr. Roberto Frias, 4200-465 Porto, Portugal
- Associate Laboratory in Chemical Engineering (ALiCE), Faculty of Engineering, University of Porto, 4200-465 Porto, Portugal
| | - M P Monteiro
- UMIB - Unidade Multidisciplinar de Investigação Biomédica, ICBAS - Instituto de Ciências Biomédicas Abel Salazar, Universidade do Porto, Porto, Portugal
- ITR - Laboratory of Integrative and Translocation Research in Population Health, Porto, Portugal
| | - J A Duarte
- TOXRUN - Toxicology Research Unit, University Institute of Health Sciences, CESPU, CRL, Gandra, Portugal
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7
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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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8
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Swanson DL, Zhang Y, Jimenez AG. Skeletal muscle and metabolic flexibility in response to changing energy demands in wild birds. Front Physiol 2022; 13:961392. [PMID: 35936893 PMCID: PMC9353400 DOI: 10.3389/fphys.2022.961392] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2022] [Accepted: 06/29/2022] [Indexed: 12/20/2022] Open
Abstract
Phenotypically plastic responses of animals to adjust to environmental variation are pervasive. Reversible plasticity (i.e., phenotypic flexibility), where adult phenotypes can be reversibly altered according to prevailing environmental conditions, allow for better matching of phenotypes to the environment and can generate fitness benefits but may also be associated with costs that trade-off with capacity for flexibility. Here, we review the literature on avian metabolic and muscle plasticity in response to season, temperature, migration and experimental manipulation of flight costs, and employ an integrative approach to explore the phenotypic flexibility of metabolic rates and skeletal muscle in wild birds. Basal (minimum maintenance metabolic rate) and summit (maximum cold-induced metabolic rate) metabolic rates are flexible traits in birds, typically increasing with increasing energy demands. Because skeletal muscles are important for energy use at the organismal level, especially to maximum rates of energy use during exercise or shivering thermogenesis, we consider flexibility of skeletal muscle at the tissue and ultrastructural levels in response to variations in the thermal environment and in workloads due to flight exercise. We also examine two major muscle remodeling regulatory pathways: myostatin and insulin-like growth factor -1 (IGF-1). Changes in myostatin and IGF-1 pathways are sometimes, but not always, regulated in a manner consistent with metabolic rate and muscle mass flexibility in response to changing energy demands in wild birds, but few studies have examined such variation so additional study is needed to fully understand roles for these pathways in regulating metabolic flexibility in birds. Muscle ultrastrutural variation in terms of muscle fiber diameter and associated myonuclear domain (MND) in birds is plastic and highly responsive to thermal variation and increases in workload, however, only a few studies have examined ultrastructural flexibility in avian muscle. Additionally, the relationship between myostatin, IGF-1, and satellite cell (SC) proliferation as it relates to avian muscle flexibility has not been addressed in birds and represents a promising avenue for future study.
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Affiliation(s)
- David L. Swanson
- Department of Biology, University of South Dakota, Vermillion, SD, United States
| | - Yufeng Zhang
- College of Health Science, University of Memphis, Memphis, TN, United States
| | - Ana Gabriela Jimenez
- Department of Biology, Colgate University, Hamilton, NY, United States
- *Correspondence: Ana Gabriela Jimenez,
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9
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Sun Y, Wang Z, Nie C, Xue L, Wang Y, Liu J, Fan M, Zhang D, He R, Zhang X, Qian H, Chow BKC, Li Y, Wang L. Hydroxysafflor yellow A triggered a fast-to-slow muscle fiber-type conversion via regulating FoxO1 in myocytes. Food Funct 2022; 13:6317-6328. [PMID: 35611953 DOI: 10.1039/d1fo03612b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Hydroxysafflor yellow A (HSYA) is the main bioactive component of safflower and has been reported to have significant health-promoting abilities. However, the regulation of HSYA on different types of skeletal myofibers is largely unknown. Here, in vitro experiments found that the water extract of safflower could significantly increase MyHC I, MB and Tnni1 mRNA expression while downregulating MyHC IIb mRNA expression. Furthermore, HSYA triggered fast-to-slow fiber-type switching and increased gene expression related to mitochondrial biosynthesis both in vitro and in vivo. Autodock analyses proved that FoxO1 is a potential target of HSYA, and qRT-PCR and western blotting further showed that HSYA significantly promoted the activation of the FoxO1 signaling pathway. Additionally, the levels of PGC1α, downstream of FoxO1, also significantly increased after HSYA treatment. Together, our findings suggested that HSYA triggered a fast-to-slow myofiber-type shift through the FoxO1 signaling pathway.
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Affiliation(s)
- Yujie Sun
- State Key Laboratory of Food Science and Technology, School of Food Science and Technology, Jiangnan University, Wuxi 214122, China.
| | - Zhijun Wang
- COFCO Aerocean Oils & Grain Industrial Co. Ltd, Shawan, No. 1 West Park Road, West Urumqi Road, Shawan County, Tacheng District, Xinjiang Province 832100, China
| | - Chenzhipeng Nie
- State Key Laboratory of Food Science and Technology, School of Food Science and Technology, Jiangnan University, Wuxi 214122, China.
| | - Lamei Xue
- State Key Laboratory of Food Science and Technology, School of Food Science and Technology, Jiangnan University, Wuxi 214122, China.
| | - Yu Wang
- State Key Laboratory of Food Science and Technology, School of Food Science and Technology, Jiangnan University, Wuxi 214122, China.
| | - Jinxin Liu
- State Key Laboratory of Food Science and Technology, School of Food Science and Technology, Jiangnan University, Wuxi 214122, China.
| | - Mingcong Fan
- State Key Laboratory of Food Science and Technology, School of Food Science and Technology, Jiangnan University, Wuxi 214122, China.
| | - Duo Zhang
- Clinical and Experimental Therapeutics, College of Pharmacy, University of Georgia and Charlie Norwood VA Medical Center, Augusta, Georgia, USA
| | - Ruikun He
- BYHEALTH Institute of Nutrition & Health, No. 3 Kehui 3rd Street, No. 99 Kexue Avenue Central, Huangpu District, Guangzhou 510663, China
| | - Xuguang Zhang
- BYHEALTH Institute of Nutrition & Health, No. 3 Kehui 3rd Street, No. 99 Kexue Avenue Central, Huangpu District, Guangzhou 510663, China
| | - Haifeng Qian
- State Key Laboratory of Food Science and Technology, School of Food Science and Technology, Jiangnan University, Wuxi 214122, China.
| | - Billy K C Chow
- School of Biological Sciences, University of Hong Kong, Hong Kong, China
| | - Yan Li
- State Key Laboratory of Food Science and Technology, School of Food Science and Technology, Jiangnan University, Wuxi 214122, China.
| | - Li Wang
- State Key Laboratory of Food Science and Technology, School of Food Science and Technology, Jiangnan University, Wuxi 214122, China.
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10
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Creisméas A, Gazaille C, Bourdon A, Lallemand MA, François V, Allais M, Ledevin M, Larcher T, Toumaniantz G, Lafoux A, Huchet C, Anegon I, Adjali O, Le Guiner C, Fraysse B. TRPC3, but not TRPC1, as a good therapeutic target for standalone or complementary treatment of DMD. J Transl Med 2021; 19:519. [PMID: 34930315 PMCID: PMC8686557 DOI: 10.1186/s12967-021-03191-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2021] [Accepted: 12/09/2021] [Indexed: 12/12/2022] Open
Abstract
Background Duchenne muscular dystrophy (DMD) is an X-linked inherited disease caused by mutations in the gene encoding dystrophin that leads to a severe and ultimately life limiting muscle-wasting condition. Recombinant adeno-associated vector (rAAV)-based gene therapy is promising, but the size of the full-length dystrophin cDNA exceeds the packaging capacity of a rAAV. Alternative or complementary strategies that could treat DMD patients are thus needed. Intracellular calcium overload due to a sarcolemma permeability to calcium (SPCa) increase is an early and critical step of the DMD pathogenesis. We assessed herein whether TRPC1 and TRPC3 calcium channels may be involved in skeletal muscle SPCa alterations and could represent therapeutic targets to treat DMD. Methods All experiments were conducted in the DMDmdx rat, an animal model that closely reproduces the human DMD disease. We measured the cytosolic calcium concentration ([Ca2+]c) and SPCa in EDL (Extensor Digitorum Longus) muscle fibers from age-matched WT and DMDmdx rats of 1.5 to 7 months old. TRPC1 and TRPC3 expressions were measured in the EDL muscles at both the mRNA and protein levels, by RT-qPCR, western blot and immunocytofluorescence analysis. Results As expected from the malignant hyperthermia like episodes observed in several DMDmdx rats, calcium homeostasis alterations were confirmed by measurements of early increases in [Ca2+]c and SPCa in muscle fibers. TRPC3 and TRPC1 protein levels were increased in DMDmdx rats. This was observed as soon as 1.5 months of age for TRPC3 but only at 7 months of age for TRPC1. A slight but reliable shift of the TRPC3 apparent molecular weight was observed in DMDmdx rat muscles. Intracellular localization of both channels was not altered. We thus focused our attention on TRPC3. Application of Pyr10, a specific inhibitor of TRPC3, abolished the differences between SPCa values measured in WT and DMDmdx. Finally, we showed that a rAAV-microdystrophin based treatment induced a high microdystrophin expression but only partial prevention of calcium homeostasis alterations, skeletal muscle force and TRPC3 protein increase. Conclusions All together our results show that correcting TRPC3 channel expression and/or activity appear to be a promising approach as a single or as a rAAV-based complementary therapy to treat DMD.
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Affiliation(s)
- Anna Creisméas
- Nantes Gene Therapy Laboratory, Université de Nantes, INSERM UMR 1089, IRS 2 Nantes Biotech, CHU de Nantes, 22, Boulevard Bénoni Goullin, 44200, Nantes, France
| | - Claire Gazaille
- Nantes Gene Therapy Laboratory, Université de Nantes, INSERM UMR 1089, IRS 2 Nantes Biotech, CHU de Nantes, 22, Boulevard Bénoni Goullin, 44200, Nantes, France
| | - Audrey Bourdon
- Nantes Gene Therapy Laboratory, Université de Nantes, INSERM UMR 1089, IRS 2 Nantes Biotech, CHU de Nantes, 22, Boulevard Bénoni Goullin, 44200, Nantes, France
| | - Marc-Antoine Lallemand
- Nantes Gene Therapy Laboratory, Université de Nantes, INSERM UMR 1089, IRS 2 Nantes Biotech, CHU de Nantes, 22, Boulevard Bénoni Goullin, 44200, Nantes, France
| | - Virginie François
- Nantes Gene Therapy Laboratory, Université de Nantes, INSERM UMR 1089, IRS 2 Nantes Biotech, CHU de Nantes, 22, Boulevard Bénoni Goullin, 44200, Nantes, France
| | - Marine Allais
- Nantes Gene Therapy Laboratory, Université de Nantes, INSERM UMR 1089, IRS 2 Nantes Biotech, CHU de Nantes, 22, Boulevard Bénoni Goullin, 44200, Nantes, France
| | | | | | - Gilles Toumaniantz
- L'Institut du Thorax, Université de Nantes, CNRS, INSERM UMR 1087, Nantes, France
| | - Aude Lafoux
- Therassay Platform, Capacités, Université de Nantes, Nantes, France
| | - Corinne Huchet
- Nantes Gene Therapy Laboratory, Université de Nantes, INSERM UMR 1089, IRS 2 Nantes Biotech, CHU de Nantes, 22, Boulevard Bénoni Goullin, 44200, Nantes, France
| | - Ignacio Anegon
- INSERM, UMR 1064-Center for Research in Transplantation and Immunology, ITUN, CHU Nantes, Université de Nantes, Faculté de Médecine, Nantes, France
| | - Oumeya Adjali
- Nantes Gene Therapy Laboratory, Université de Nantes, INSERM UMR 1089, IRS 2 Nantes Biotech, CHU de Nantes, 22, Boulevard Bénoni Goullin, 44200, Nantes, France
| | - Caroline Le Guiner
- Nantes Gene Therapy Laboratory, Université de Nantes, INSERM UMR 1089, IRS 2 Nantes Biotech, CHU de Nantes, 22, Boulevard Bénoni Goullin, 44200, Nantes, France
| | - Bodvaël Fraysse
- Nantes Gene Therapy Laboratory, Université de Nantes, INSERM UMR 1089, IRS 2 Nantes Biotech, CHU de Nantes, 22, Boulevard Bénoni Goullin, 44200, Nantes, France.
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11
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Histological and biochemical evaluation of skeletal muscle in the two salmonid species Coregonus maraena and Oncorhynchus mykiss. PLoS One 2021; 16:e0255062. [PMID: 34383783 PMCID: PMC8360549 DOI: 10.1371/journal.pone.0255062] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2021] [Accepted: 07/08/2021] [Indexed: 12/03/2022] Open
Abstract
The growth of fishes and their metabolism is highly variable in fish species and is an indicator for fish fitness. Therefore, somatic growth, as a main biological process, is ecologically and economically significant. The growth differences of two closely related salmonids, rainbow trout (Oncorhynchus mykiss) and maraena whitefsh (Coregonus maraena), have not been adequately studied as a comparative study and are therefore insufficiently understood. For this reason, our aim was to examine muscle growth in more detail and provide a first complex insight into the growth and muscle metabolism of these two fish species at slaughter size. In addition to skeletal muscle composition (including nuclear counting and staining of stem and progenitor cells), biochemical characteristics, and enzyme activity (creatine kinase, lactate dehydrogenase, isocitrate dehydrogenase) of rainbow trout and maraena whitefish were determined. Our results indicate that red muscle contains cells with a smaller diameter compared to white muscle and those fibres had more stem and progenitor cells as a proportion of total nuclei. Interestingly, numerous interspecies differences were identified; in rainbow trout muscle RNA content, intermediate fibres and fibre diameter and in whitefish red muscle cross-sectional area, creatine kinase activity were higher compared to the other species at slaughter weight. The proportional reduction in red muscle area, accompanied by an increase in DNA content and a lower activity of creatine kinase, exhibited a higher degree of hypertrophic growth in rainbow trout compared to maraena whitefish, which makes this species particularly successful as an aquaculture species.
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12
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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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13
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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: 41] [Impact Index Per Article: 10.3] [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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14
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Komiya Y, Mizunoya W, Kajiwara K, Yokoyama I, Ogasawara H, Arihara K. Correlation between skeletal muscle fiber type and responses of a taste sensing system in various beef samples. Anim Sci J 2020; 91:e13425. [PMID: 32691493 PMCID: PMC7507124 DOI: 10.1111/asj.13425] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2020] [Revised: 06/04/2020] [Accepted: 06/25/2020] [Indexed: 11/29/2022]
Abstract
The difference of muscle fiber type composition affects several parameters related to meat quality; however, the relationship between muscle fiber types and meat taste is unclear. To elucidate this relationship, we determined the taste of various beef samples using a taste sensor (INSENT SA402B) and analyzed its correlation with different muscle fiber type composition. We used 22 kinds of beef samples and measured nine tastes, including the relative and change of membrane potential caused by adsorption (CPA) values, using six sensors (GL1, CT0, CA0, AAE, C00, and AE1). The taste sensor analysis indicated positive value outputs for the relative C00, AAE, and GL1 values as well as for the CPA value of AAE, which corresponded to bitterness, umami, sweetness, and richness, respectively. We found significant positive correlations of the myosin heavy chain 1 (MyHC1) composition with umami taste, and with richness. This result suggests that high levels of slow MyHC1 can induce strong umami taste and richness in beef. We expect that our results will contribute to the elucidation of the relationship between muscle fiber types and meat palatability.
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Affiliation(s)
- Yusuke Komiya
- Department of Animal Science, School of Veterinary Medicine, Kitasato University, Towada, Japan
| | - Wataru Mizunoya
- Department of Animal Science and Biotechnology, School of Veterinary Medicine, Azabu University, Sagamihara, Japan
| | - Kurumi Kajiwara
- Department of Animal Science, School of Veterinary Medicine, Kitasato University, Towada, Japan
| | - Issei Yokoyama
- Department of Animal Science, School of Veterinary Medicine, Kitasato University, Towada, Japan
| | - Hideki Ogasawara
- Field Science Center, School of Veterinary Medicine, Kitasato University, Yakumo, Japan
| | - Keizo Arihara
- Department of Animal Science, School of Veterinary Medicine, Kitasato University, Towada, Japan
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15
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Hromowyk KJ, Talbot JC, Martin BL, Janssen PML, Amacher SL. Cell fusion is differentially regulated in zebrafish post-embryonic slow and fast muscle. Dev Biol 2020; 462:85-100. [PMID: 32165147 PMCID: PMC7225055 DOI: 10.1016/j.ydbio.2020.03.005] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2019] [Revised: 02/08/2020] [Accepted: 03/03/2020] [Indexed: 12/13/2022]
Abstract
Skeletal muscle fusion occurs during development, growth, and regeneration. To investigate how muscle fusion compares among different muscle cell types and developmental stages, we studied muscle cell fusion over time in wild-type, myomaker (mymk), and jam2a mutant zebrafish. Using live imaging, we show that embryonic myoblast elongation and fusion correlate tightly with slow muscle cell migration. In wild-type embryos, only fast muscle fibers are multinucleate, consistent with previous work showing that the cell fusion regulator gene mymk is specifically expressed throughout the embryonic fast muscle domain. However, by 3 weeks post-fertilization, slow muscle fibers also become multinucleate. At this late-larval stage, mymk is not expressed in muscle fibers, but is expressed in small cells near muscle fibers. Although previous work showed that both mymk and jam2a are required for embryonic fast muscle cell fusion, we observe that muscle force and function is almost normal in mymk and jam2a mutant embryos, despite the lack of fast muscle multinucleation. We show that genetic requirements change post-embryonically, with jam2a becoming much less important by late-larval stages and mymk now required for muscle fusion and growth in both fast and slow muscle cell types. Correspondingly, adult mymk mutants perform poorly in sprint and endurance tests compared to wild-type and jam2a mutants. We show that adult mymk mutant muscle contains small mononucleate myofibers with average myonuclear domain size equivalent to that in wild type adults. The mymk mutant fibers have decreased Laminin expression and increased numbers of Pax7-positive cells, suggesting that impaired fiber growth and active regeneration contribute to the muscle phenotype. Our findings identify several aspects of muscle fusion that change with time in slow and fast fibers as zebrafish develop beyond embryonic stages.
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Affiliation(s)
- Kimberly J Hromowyk
- Department of Molecular Genetics and Biological Chemistry and Pharmacology, The Ohio State University, Columbus, OH, 43210, USA; Center for Muscle Health and Neuromuscular Disorders, The Ohio State University and Nationwide Children's Hospital, Columbus, OH, 43210, USA; Molecular, Cellular, and Developmental Biology Graduate Program, The Ohio State University, Columbus, OH, 43210, USA
| | - Jared C Talbot
- Department of Molecular Genetics and Biological Chemistry and Pharmacology, The Ohio State University, Columbus, OH, 43210, USA; Center for Muscle Health and Neuromuscular Disorders, The Ohio State University and Nationwide Children's Hospital, Columbus, OH, 43210, USA.
| | - Brit L Martin
- Center for Muscle Health and Neuromuscular Disorders, The Ohio State University and Nationwide Children's Hospital, Columbus, OH, 43210, USA; Molecular, Cellular, and Developmental Biology Graduate Program, The Ohio State University, Columbus, OH, 43210, USA; Department of Physiology and Cell Biology, The Ohio State University, Columbus, OH, 43210, USA
| | - Paul M L Janssen
- Center for Muscle Health and Neuromuscular Disorders, The Ohio State University and Nationwide Children's Hospital, Columbus, OH, 43210, USA; Department of Physiology and Cell Biology, The Ohio State University, Columbus, OH, 43210, USA; Davis Heart and Lung Research Institute, The Ohio State University, Columbus, OH, 43210, USA
| | - Sharon L Amacher
- Department of Molecular Genetics and Biological Chemistry and Pharmacology, The Ohio State University, Columbus, OH, 43210, USA; Center for Muscle Health and Neuromuscular Disorders, The Ohio State University and Nationwide Children's Hospital, Columbus, OH, 43210, USA; Center for RNA Biology, The Ohio State University, Columbus, OH, 43210, USA.
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16
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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: 37] [Impact Index Per Article: 9.3] [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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17
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Roberts MD, Mobley CB, Vann CG, Haun CT, Schoenfeld BJ, Young KC, Kavazis AN. Synergist ablation-induced hypertrophy occurs more rapidly in the plantaris than soleus muscle in rats due to different molecular mechanisms. Am J Physiol Regul Integr Comp Physiol 2019; 318:R360-R368. [PMID: 31850817 DOI: 10.1152/ajpregu.00304.2019] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
We examined molecular mechanisms that were altered during rapid soleus (type I fiber-dominant) and plantaris (type II fiber-dominant) hypertrophy in rats. Twelve Wistar rats (3.5 mo old; 6 female, 6 male) were subjected to surgical right-leg soleus and plantaris dual overload [synergist ablation (SA)], and sham surgeries were performed on left legs (CTL). At 14 days after surgery, the muscles were dissected. Plantaris mass was 27% greater in the SA than CTL leg (P < 0.001), soleus mass was 13% greater in the SA than CTL leg (P < 0.001), and plantaris mass was higher than soleus mass in the SA leg (P = 0.001). Plantaris total RNA concentrations and estimated total RNA levels (suggestive of ribosome density) were 19% and 47% greater in the SA than CTL leg (P < 0.05), protein synthesis levels were 64% greater in the SA than CTL leg (P = 0.038), and satellite cell number per fiber was 60% greater in the SA than CTL leg (P = 0.003); no differences in these metrics were observed between soleus SA and CTL legs. Plantaris, as well as soleus, 20S proteasome activity was lower in the SA than CTL leg (P < 0.05), although the degree of downregulation was greater in the plantaris than soleus muscle (-63% vs. -20%, P = 0.001). These data suggest that early-phase plantaris hypertrophy occurs more rapidly than soleus hypertrophy, which coincided with greater increases in ribosome biogenesis, protein synthesis, and satellite cell density, as well as greater decrements in 20S proteasome activity, in the plantaris muscle.
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Affiliation(s)
- Michael D Roberts
- School of Kinesiology, Auburn University, Auburn, Alabama.,Department of Cell Biology and Physiology, Edward Via College of Veterinary Medicine, Auburn, Alabama
| | - Christopher B Mobley
- Department of Physiology, College of Medicine, University of Kentucky, Lexington, Kentucky.,Center for Muscle Biology, University of Kentucky, Lexington, Kentucky
| | | | - Cody T Haun
- Department of Exercise Science, LaGrange College, LaGrange, Georgia
| | - Brad J Schoenfeld
- Department of Health Sciences, City University of New York Lehman College, Bronx, New York
| | - Kaelin C Young
- School of Kinesiology, Auburn University, Auburn, Alabama.,Department of Cell Biology and Physiology, Edward Via College of Veterinary Medicine, Auburn, Alabama
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18
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Larson L, Lioy J, Johnson J, Medler S. Transitional Hybrid Skeletal Muscle Fibers in Rat Soleus Development. J Histochem Cytochem 2019; 67:891-900. [PMID: 31510854 PMCID: PMC6882066 DOI: 10.1369/0022155419876421] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2019] [Accepted: 08/12/2019] [Indexed: 12/22/2022] Open
Abstract
Skeletal muscles comprise hundreds of individual muscle fibers, with each possessing specialized contractile properties. Skeletal muscles are recognized as being highly plastic, meaning that the physiological properties of single muscle fibers can change with appropriate use. During fiber type transitions, one myosin heavy chain isoform is exchanged for another and over time the fundamental nature of the fiber adapts to become a different fiber type. Within the rat triceps surae complex, the soleus muscle starts out as a muscle comprised of a mixture type IIA and type I fibers. As neonatal rats grow and mature, the soleus undergoes a near complete transition into a muscle with close to 100% type I fibers at maturity. We used immunohistochemistry and single fiber SDS-PAGE to track the transformation of type IIA into type I fibers. We found that transitioning fibers progressively incorporate new myofibrils containing type I myosin into existing type IIA fibers. During this exchange, distinct type I-containing myofibrils are segregated among IIA myofibrils. The individual myofibrils within existing muscle fibers thus appear to represent the functional unit that is exchanged during fiber type transitions that occur as part of normal muscle development.
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Affiliation(s)
- Lauren Larson
- Biology Department, State University of New York at Fredonia, Fredonia, NY, USA
| | - Jessica Lioy
- Biology Department, State University of New York at Fredonia, Fredonia, NY, USA
| | - Jordan Johnson
- Biology Department, State University of New York at Fredonia, Fredonia, NY, USA
| | - Scott Medler
- Biology Department, State University of New York at Fredonia, Fredonia, NY, USA
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19
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Medler S. Mixing it up: the biological significance of hybrid skeletal muscle fibers. ACTA ACUST UNITED AC 2019; 222:222/23/jeb200832. [PMID: 31784473 DOI: 10.1242/jeb.200832] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Skeletal muscle fibers are classified according to the myosin heavy chain (MHC) isoforms and other myofibrillar proteins expressed within these cells. In addition to 'pure' fibers expressing single MHC isoforms, many fibers are 'hybrids' that co-express two or more different isoforms of MHC or other myofibrillar proteins. Although hybrid fibers have been recognized by muscle biologists for more than three decades, uncertainty persists about their prevalence in normal muscles, their role in fiber-type transitions, and what they might tell us about fiber-type regulation at the cellular and molecular levels. This Review summarizes current knowledge on the relative abundance of hybrid fibers in a variety of muscles from different species. Data from more than 150 muscles from 39 species demonstrate that hybrid fibers are common, frequently representing 25% or more of the fibers in normal muscles. Hybrid fibers appear to have two main roles: (1) they function as intermediates during the fiber-type transitions associated with skeletal muscle development, adaptation to exercise and aging; and (2) they provide a functional continuum of fiber phenotypes, as they possess physiological properties that are intermediate to those of pure fiber types. One aspect of hybrid fibers that is not widely recognized is that fiber-type asymmetries - such as dramatic differences in the MHC composition along the length of single fibers - appear to be a common aspect of many fibers. The final section of this Review examines the possible role of differential activities of nuclei in different myonuclear domains in establishing fiber-type asymmetries.
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Affiliation(s)
- Scott Medler
- Biology Department, State University of New York at Fredonia, Fredonia, NY 14063, USA
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20
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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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21
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Machek SB, Lorenz KA, Kern M, Galpin AJ, Bagley JR. Skeletal Muscle Fiber Type and Morphology in a Middle-Aged Elite Male Powerlifter Using Anabolic Steroids. ACTA ACUST UNITED AC 2019. [DOI: 10.1007/s42978-019-00039-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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22
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Landim-Vieira M, Schipper JM, Pinto JR, Chase PB. Cardiomyocyte nuclearity and ploidy: when is double trouble? J Muscle Res Cell Motil 2019; 41:329-340. [PMID: 31317457 DOI: 10.1007/s10974-019-09545-7] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2019] [Accepted: 07/12/2019] [Indexed: 01/23/2023]
Abstract
Considerable effort has gone into investigating mechanisms that underlie the developmental transition in which mammalian cardiomyocytes (CMs) switch from being able to proliferate during development, to essentially having lost that ability at maturity. This problem is interesting not only for scientific curiosity, but also for its clinical relevance because controlling the ability of mature CMs to replicate would provide a much-needed approach for restoring cardiac function in damaged hearts. In this review, we focus on the propensity of mature mammalian CMs to be multinucleated and polyploid, and the extent to which this may be necessary for normal physiology yet possibly disadvantageous in some circumstances. In this context, we explore whether the concept of the myonuclear domain (MND) in multinucleated skeletal muscle fibers might apply to cardiomyocytes, and whether cardio-MND size might be related to the transition of CMs to become multinuclear. Nuclei in CMs are almost certainly integrators of not only biochemical, but also-because of their central location within the myofibrils-mechanical information, and this multimodal, integrative function in adult CMs-involving molecules that have been extensively studied along with newly identified possibilities-could influence both gene expression as well as replication of the genome and the nuclei themselves.
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Affiliation(s)
- Maicon Landim-Vieira
- Department of Biomedical Sciences, College of Medicine, Florida State University, Tallahassee, FL, USA
| | - Joslyn M Schipper
- Department of Biomedical Sciences, College of Medicine, Florida State University, Tallahassee, FL, USA.,Department of Biological Science, Florida State University, Tallahassee, FL, USA
| | - J Renato Pinto
- Department of Biomedical Sciences, College of Medicine, Florida State University, Tallahassee, FL, USA
| | - P Bryant Chase
- Department of Biological Science, Florida State University, Tallahassee, FL, USA. .,Department of Biological Science, Florida State University, Biology Unit One Room 206, 81 Chieftain Way, Tallahassee, FL, 32306-4370, USA.
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23
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Mashima D, Oka Y, Gotoh T, Tomonaga S, Sawano S, Nakamura M, Tatsumi R, Mizunoya W. Correlation between skeletal muscle fiber type and free amino acid levels in Japanese Black steers. Anim Sci J 2019; 90:604-609. [PMID: 30811817 PMCID: PMC6594095 DOI: 10.1111/asj.13185] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2018] [Accepted: 01/18/2019] [Indexed: 11/29/2022]
Abstract
Free amino acids are important components of tastants and flavor precursors in meat. To clarify the correlation between muscle fiber type and free amino acids, we determined the concentrations of various free amino acids and dipeptides in samples of different muscle tissues (n = 21), collected from 26-month-old Japanese Black steers (n = 3) at 2 days postmortem. The proportions of the myosin heavy chain (MyHC), slow (MyHC1) and fast (MyHC2) isoforms were determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). The contents of free amino acids and dipeptides were measured by high performance liquid chromatography (HPLC). The MyHC isoform composition varied among the tissue samples. The MyHC1 proportion ranged from 6.9% ± 3.9% to 83.3% ± 16.7%. We confirmed that there was a strong positive correlation between MyHC1 composition and total free amino acid concentrations, including those for two dipeptides. Among the 31 measured free amino acids and dipeptides, 11 showed significant positive correlations and five showed significant negative correlations with MyHC1 composition. These results suggest that a high MyHC1 content induces high free amino acid contents in bovine muscles possibly because of greater oxidative metabolism. This high level of free amino acids could contribute to the intense flavor of meat that is rich in slow-twitch fibers.
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Affiliation(s)
- Daisuke Mashima
- Department of Bioresource Sciences, Faculty of Agriculture, Kyushu University, Fukuoka, Japan
| | - Yoshiaki Oka
- Department of Bioresource Sciences, Faculty of Agriculture, Kyushu University, Fukuoka, Japan
| | - Takafumi Gotoh
- Department of Bioresource Sciences, Faculty of Agriculture, Kyushu University, Fukuoka, Japan.,Department of Agricultural Sciences and Natural Resources, Faculty of Agriculture, Kagoshima University, Kagoshima, Japan
| | - Shozo Tomonaga
- Department of Bioresource Sciences, Faculty of Agriculture, Kyushu University, Fukuoka, Japan.,Division of Applied Biosciences, Graduate School of Agriculture, Kyoto University, Kyoto, Japan
| | - Shoko Sawano
- Department of Bioresource Sciences, Faculty of Agriculture, Kyushu University, Fukuoka, Japan
| | - Mako Nakamura
- Department of Bioresource Sciences, Faculty of Agriculture, Kyushu University, Fukuoka, Japan
| | - Ryuichi Tatsumi
- Department of Bioresource Sciences, Faculty of Agriculture, Kyushu University, Fukuoka, Japan
| | - Wataru Mizunoya
- Department of Bioresource Sciences, Faculty of Agriculture, Kyushu University, Fukuoka, Japan
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24
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Larsson L, Degens H, Li M, Salviati L, Lee YI, Thompson W, Kirkland JL, Sandri M. Sarcopenia: Aging-Related Loss of Muscle Mass and Function. Physiol Rev 2019; 99:427-511. [PMID: 30427277 DOI: 10.1152/physrev.00061.2017] [Citation(s) in RCA: 710] [Impact Index Per Article: 142.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Sarcopenia is a loss of muscle mass and function in the elderly that reduces mobility, diminishes quality of life, and can lead to fall-related injuries, which require costly hospitalization and extended rehabilitation. This review focuses on the aging-related structural changes and mechanisms at cellular and subcellular levels underlying changes in the individual motor unit: specifically, the perikaryon of the α-motoneuron, its neuromuscular junction(s), and the muscle fibers that it innervates. Loss of muscle mass with aging, which is largely due to the progressive loss of motoneurons, is associated with reduced muscle fiber number and size. Muscle function progressively declines because motoneuron loss is not adequately compensated by reinnervation of muscle fibers by the remaining motoneurons. At the intracellular level, key factors are qualitative changes in posttranslational modifications of muscle proteins and the loss of coordinated control between contractile, mitochondrial, and sarcoplasmic reticulum protein expression. Quantitative and qualitative changes in skeletal muscle during the process of aging also have been implicated in the pathogenesis of acquired and hereditary neuromuscular disorders. In experimental models, specific intervention strategies have shown encouraging results on limiting deterioration of motor unit structure and function under conditions of impaired innervation. Translated to the clinic, if these or similar interventions, by saving muscle and improving mobility, could help alleviate sarcopenia in the elderly, there would be both great humanitarian benefits and large cost savings for health care systems.
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Affiliation(s)
- Lars Larsson
- Department of Physiology and Pharmacology, Basic and Clinical Muscle Biology Group, Karolinska Institutet , Stockholm , Sweden ; Section of Clinical Neurophysiology, Department of Clinical Neuroscience, Karolinska Institutet , Stockholm , Sweden ; Department of Biobehavioral Health, The Pennsylvania State University , University Park, Pennsylvania ; School of Healthcare Science, Metropolitan University , Manchester , United Kingdom ; Institute of Sport Science and Innovations, Lithuanian Sports University , Kaunas , Lithuania ; Clinical Genetics Unit, Department of Woman and Child Health, University of Padova , Padova , Italy ; IRP Città della Speranza, Padova , Italy ; Department of Biology, Texas A&M University , College Station, Texas ; Robert and Arlene Kogod Center on Aging, Mayo Clinic , Rochester, Minnesota ; Department of Biomedical Science, Venetian Institute of Molecular Medicine, University of Padova , Padova , Italy
| | - Hans Degens
- Department of Physiology and Pharmacology, Basic and Clinical Muscle Biology Group, Karolinska Institutet , Stockholm , Sweden ; Section of Clinical Neurophysiology, Department of Clinical Neuroscience, Karolinska Institutet , Stockholm , Sweden ; Department of Biobehavioral Health, The Pennsylvania State University , University Park, Pennsylvania ; School of Healthcare Science, Metropolitan University , Manchester , United Kingdom ; Institute of Sport Science and Innovations, Lithuanian Sports University , Kaunas , Lithuania ; Clinical Genetics Unit, Department of Woman and Child Health, University of Padova , Padova , Italy ; IRP Città della Speranza, Padova , Italy ; Department of Biology, Texas A&M University , College Station, Texas ; Robert and Arlene Kogod Center on Aging, Mayo Clinic , Rochester, Minnesota ; Department of Biomedical Science, Venetian Institute of Molecular Medicine, University of Padova , Padova , Italy
| | - Meishan Li
- Department of Physiology and Pharmacology, Basic and Clinical Muscle Biology Group, Karolinska Institutet , Stockholm , Sweden ; Section of Clinical Neurophysiology, Department of Clinical Neuroscience, Karolinska Institutet , Stockholm , Sweden ; Department of Biobehavioral Health, The Pennsylvania State University , University Park, Pennsylvania ; School of Healthcare Science, Metropolitan University , Manchester , United Kingdom ; Institute of Sport Science and Innovations, Lithuanian Sports University , Kaunas , Lithuania ; Clinical Genetics Unit, Department of Woman and Child Health, University of Padova , Padova , Italy ; IRP Città della Speranza, Padova , Italy ; Department of Biology, Texas A&M University , College Station, Texas ; Robert and Arlene Kogod Center on Aging, Mayo Clinic , Rochester, Minnesota ; Department of Biomedical Science, Venetian Institute of Molecular Medicine, University of Padova , Padova , Italy
| | - Leonardo Salviati
- Department of Physiology and Pharmacology, Basic and Clinical Muscle Biology Group, Karolinska Institutet , Stockholm , Sweden ; Section of Clinical Neurophysiology, Department of Clinical Neuroscience, Karolinska Institutet , Stockholm , Sweden ; Department of Biobehavioral Health, The Pennsylvania State University , University Park, Pennsylvania ; School of Healthcare Science, Metropolitan University , Manchester , United Kingdom ; Institute of Sport Science and Innovations, Lithuanian Sports University , Kaunas , Lithuania ; Clinical Genetics Unit, Department of Woman and Child Health, University of Padova , Padova , Italy ; IRP Città della Speranza, Padova , Italy ; Department of Biology, Texas A&M University , College Station, Texas ; Robert and Arlene Kogod Center on Aging, Mayo Clinic , Rochester, Minnesota ; Department of Biomedical Science, Venetian Institute of Molecular Medicine, University of Padova , Padova , Italy
| | - Young Il Lee
- Department of Physiology and Pharmacology, Basic and Clinical Muscle Biology Group, Karolinska Institutet , Stockholm , Sweden ; Section of Clinical Neurophysiology, Department of Clinical Neuroscience, Karolinska Institutet , Stockholm , Sweden ; Department of Biobehavioral Health, The Pennsylvania State University , University Park, Pennsylvania ; School of Healthcare Science, Metropolitan University , Manchester , United Kingdom ; Institute of Sport Science and Innovations, Lithuanian Sports University , Kaunas , Lithuania ; Clinical Genetics Unit, Department of Woman and Child Health, University of Padova , Padova , Italy ; IRP Città della Speranza, Padova , Italy ; Department of Biology, Texas A&M University , College Station, Texas ; Robert and Arlene Kogod Center on Aging, Mayo Clinic , Rochester, Minnesota ; Department of Biomedical Science, Venetian Institute of Molecular Medicine, University of Padova , Padova , Italy
| | - Wesley Thompson
- Department of Physiology and Pharmacology, Basic and Clinical Muscle Biology Group, Karolinska Institutet , Stockholm , Sweden ; Section of Clinical Neurophysiology, Department of Clinical Neuroscience, Karolinska Institutet , Stockholm , Sweden ; Department of Biobehavioral Health, The Pennsylvania State University , University Park, Pennsylvania ; School of Healthcare Science, Metropolitan University , Manchester , United Kingdom ; Institute of Sport Science and Innovations, Lithuanian Sports University , Kaunas , Lithuania ; Clinical Genetics Unit, Department of Woman and Child Health, University of Padova , Padova , Italy ; IRP Città della Speranza, Padova , Italy ; Department of Biology, Texas A&M University , College Station, Texas ; Robert and Arlene Kogod Center on Aging, Mayo Clinic , Rochester, Minnesota ; Department of Biomedical Science, Venetian Institute of Molecular Medicine, University of Padova , Padova , Italy
| | - James L Kirkland
- Department of Physiology and Pharmacology, Basic and Clinical Muscle Biology Group, Karolinska Institutet , Stockholm , Sweden ; Section of Clinical Neurophysiology, Department of Clinical Neuroscience, Karolinska Institutet , Stockholm , Sweden ; Department of Biobehavioral Health, The Pennsylvania State University , University Park, Pennsylvania ; School of Healthcare Science, Metropolitan University , Manchester , United Kingdom ; Institute of Sport Science and Innovations, Lithuanian Sports University , Kaunas , Lithuania ; Clinical Genetics Unit, Department of Woman and Child Health, University of Padova , Padova , Italy ; IRP Città della Speranza, Padova , Italy ; Department of Biology, Texas A&M University , College Station, Texas ; Robert and Arlene Kogod Center on Aging, Mayo Clinic , Rochester, Minnesota ; Department of Biomedical Science, Venetian Institute of Molecular Medicine, University of Padova , Padova , Italy
| | - Marco Sandri
- Department of Physiology and Pharmacology, Basic and Clinical Muscle Biology Group, Karolinska Institutet , Stockholm , Sweden ; Section of Clinical Neurophysiology, Department of Clinical Neuroscience, Karolinska Institutet , Stockholm , Sweden ; Department of Biobehavioral Health, The Pennsylvania State University , University Park, Pennsylvania ; School of Healthcare Science, Metropolitan University , Manchester , United Kingdom ; Institute of Sport Science and Innovations, Lithuanian Sports University , Kaunas , Lithuania ; Clinical Genetics Unit, Department of Woman and Child Health, University of Padova , Padova , Italy ; IRP Città della Speranza, Padova , Italy ; Department of Biology, Texas A&M University , College Station, Texas ; Robert and Arlene Kogod Center on Aging, Mayo Clinic , Rochester, Minnesota ; Department of Biomedical Science, Venetian Institute of Molecular Medicine, University of Padova , Padova , Italy
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25
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Harrison JF. Approaches for testing hypotheses for the hypometric scaling of aerobic metabolic rate in animals. Am J Physiol Regul Integr Comp Physiol 2018; 315:R879-R894. [DOI: 10.1152/ajpregu.00165.2018] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Hypometric scaling of aerobic metabolism [larger organisms have lower mass-specific metabolic rates (MR/g)] is nearly universal for interspecific comparisons among animals, yet we lack an agreed upon explanation for this pattern. If physiological constraints on the function of larger animals occur and limit MR/g, these should be observable as direct constraints on animals of extant species and/or as evolved responses to compensate for the proposed constraint. There is evidence for direct constraints and compensatory responses to O2 supply constraint in skin-breathing animals, but not in vertebrates with gas-exchange organs. The duration of food retention in the gut is longer for larger birds and mammals, consistent with a direct constraint on nutrient uptake across the gut wall, but there is little evidence for evolving compensatory responses to gut transport constraints in larger animals. Larger placental mammals (but not marsupials or birds) show evidence of greater challenges with heat dissipation, but there is little evidence for compensatory adaptations to enhance heat loss in larger endotherms, suggesting that metabolic rate (MR) more generally balances heat loss for thermoregulation in endotherms. Size-dependent patterns in many molecular, physiological, and morphological properties are consistent with size-dependent natural selection, such as stronger selection for neurolocomotor performance and growth rate in smaller animals and stronger selection for safety and longevity in larger animals. Hypometric scaling of MR very likely arises from different mechanisms in different taxa and conditions, consistent with the diversity of scaling slopes for MR.
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Affiliation(s)
- Jon F. Harrison
- School of Life Sciences, Arizona State University, Tempe, Arizona
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26
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Xenopus SOX5 enhances myogenic transcription indirectly through transrepression. Dev Biol 2018; 442:262-275. [PMID: 30071218 DOI: 10.1016/j.ydbio.2018.07.025] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2018] [Revised: 07/16/2018] [Accepted: 07/28/2018] [Indexed: 02/06/2023]
Abstract
In anamniotes, somite compartimentalization in the lateral somitic domain leads simultaneously to myotome and dermomyotome formation. In the myotome, Xenopus Sox5 is co-expressed with Myod1 in the course of myogenic differentiation. Here, we studied the function of Sox5 using a Myod1-induced myogenic transcription assay in pluripotent cells of animal caps. We found that Sox5 enhances myogenic transcription of muscle markers Des, Actc1, Ckm and MyhE3. The use of chimeric transactivating or transrepressive Sox5 proteins indicates that Sox5 acts as a transrepressor and indirectly stimulates myogenic transcription except for the slow muscle-specific genes Myh7L, Myh7S, Myl2 and Tnnc1. We showed that this role is shared by Sox6, which is structurally similar to Sox5, both belonging to the SoxD subfamily of transcription factors. Moreover, Sox5 can antagonize the inhibitory function of Meox2 on myogenic differentiation. Meox2 which is a dermomyotome marker, represses myogenic transcription in Myod-induced myogenic transcription assay and in Nodal5-induced mesoderm from animal cap assay. The inhibitory function of Meox2 and the pro-myogenic function of Sox5 were confirmed during Xenopus normal development by the use of translation-blocking oligomorpholinos and dexamethasone inducible chimeric Sox5 and Meox2 proteins. We have therefore identified a new function for SoxD proteins in muscle cells, which can indirectly enhance myogenic transcription through transrepression, in addition to the previously identified function as a direct repressor of slow muscle-specific genes.
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27
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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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28
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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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29
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Iyer SR, Shah SB, Valencia AP, Schneider MF, Hernández-Ochoa EO, Stains JP, Blemker SS, Lovering RM. Altered nuclear dynamics in MDX myofibers. J Appl Physiol (1985) 2016; 122:470-481. [PMID: 27979987 DOI: 10.1152/japplphysiol.00857.2016] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2016] [Revised: 12/02/2016] [Accepted: 12/06/2016] [Indexed: 01/17/2023] Open
Abstract
Duchenne muscular dystrophy (DMD) is a genetic disorder in which the absence of dystrophin leads to progressive muscle degeneration and weakness. Although the genetic basis is known, the pathophysiology of dystrophic skeletal muscle remains unclear. We examined nuclear movement in wild-type (WT) and muscular dystrophy mouse model for DMD (MDX) (dystrophin-null) mouse myofibers. We also examined expression of proteins in the linkers of nucleoskeleton and cytoskeleton (LINC) complex, as well as nuclear transcriptional activity via histone H3 acetylation and polyadenylate-binding nuclear protein-1. Because movement of nuclei is not only LINC dependent but also microtubule dependent, we analyzed microtubule density and organization in WT and MDX myofibers, including the application of a unique 3D tool to assess microtubule core structure. Nuclei in MDX myofibers were more mobile than in WT myofibers for both distance traveled and velocity. MDX muscle shows reduced expression and labeling intensity of nesprin-1, a LINC protein that attaches the nucleus to the microtubule and actin cytoskeleton. MDX nuclei also showed altered transcriptional activity. Previous studies established that microtubule structure at the cortex is disrupted in MDX myofibers; our analyses extend these findings by showing that microtubule structure in the core is also disrupted. In addition, we studied malformed MDX myofibers to better understand the role of altered myofiber morphology vs. microtubule architecture in the underlying susceptibility to injury seen in dystrophic muscles. We incorporated morphological and microtubule architectural concepts into a simplified finite element mathematical model of myofiber mechanics, which suggests a greater contribution of myofiber morphology than microtubule structure to muscle biomechanical performance.NEW & NOTEWORTHY Microtubules provide the means for nuclear movement but show altered organization in the muscular dystrophy mouse model (MDX) (dystrophin-null) muscle. Here, MDX myofibers show increased nuclear movement, altered transcriptional activity, and altered linkers of nucleoskeleton and cytoskeleton complex expression compared with healthy myofibers. Microtubule architecture was incorporated in finite element modeling of passive stretch, revealing a role of fiber malformation, commonly found in MDX muscle. The results suggest that alterations in microtubule architecture in MDX muscle affect nuclear movement, which is essential for muscle function.
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Affiliation(s)
- Shama R Iyer
- Department of Orthopaedics, University of Maryland School of Medicine, Baltimore, Maryland
| | - Sameer B Shah
- Departments of Orthopaedic Surgery and Bioengineering, University of California San Diego, La Jolla, California
| | - Ana P Valencia
- Department of Orthopaedics, University of Maryland School of Medicine, Baltimore, Maryland
| | - Martin F Schneider
- Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, Baltimore, Maryland
| | - Erick O Hernández-Ochoa
- Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, Baltimore, Maryland
| | - Joseph P Stains
- Department of Orthopaedics, University of Maryland School of Medicine, Baltimore, Maryland
| | - Silvia S Blemker
- Department of Biomedical Engineering and Mechanical and Aerospace Engineering, University of Virginia, Charlottesville, Virginia; and
| | - Richard M Lovering
- Department of Orthopaedics, University of Maryland School of Medicine, Baltimore, Maryland; .,Department of Physiology, University of Maryland School of Medicine, Baltimore, Maryland
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30
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Qaisar R, Bhaskaran S, Van Remmen H. Muscle fiber type diversification during exercise and regeneration. Free Radic Biol Med 2016; 98:56-67. [PMID: 27032709 DOI: 10.1016/j.freeradbiomed.2016.03.025] [Citation(s) in RCA: 85] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/28/2015] [Revised: 03/01/2016] [Accepted: 03/24/2016] [Indexed: 01/15/2023]
Abstract
The plasticity of skeletal muscle can be traced down to extensive metabolic, structural and molecular remodeling at the single fiber level. Skeletal muscle is comprised of different fiber types that are the basis of muscle plasticity in response to various functional demands. Resistance and endurance exercises are two external stimuli that differ in their duration and intensity of contraction and elicit markedly different responses in muscles adaptation. Further, eccentric contractions that are associated with exercise-induced injuries, elicit varied muscle adaptation and regenerative responses. Most adaptive changes are fiber type-specific and are highly influenced by diverse structural, metabolic and functional characteristics of individual fiber types. Regulation of signaling pathways by reactive oxygen species (ROS) and oxidative stress also plays an important role in muscle fiber adaptation during exercise. This review focuses on cellular and molecular responses that regulate the adaptation of skeletal muscle to exercise and exercise-related injuries.
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Affiliation(s)
- Rizwan Qaisar
- Aging and Metabolism Research Program, Oklahoma Medical Research Foundation, 825 NE 13th Street, Oklahoma City, OK 73104, USA
| | - Shylesh Bhaskaran
- Aging and Metabolism Research Program, Oklahoma Medical Research Foundation, 825 NE 13th Street, Oklahoma City, OK 73104, USA
| | - Holly Van Remmen
- Aging and Metabolism Research Program, Oklahoma Medical Research Foundation, 825 NE 13th Street, Oklahoma City, OK 73104, USA.
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31
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Omairi S, Matsakas A, Degens H, Kretz O, Hansson KA, Solbrå AV, Bruusgaard JC, Joch B, Sartori R, Giallourou N, Mitchell R, Collins-Hooper H, Foster K, Pasternack A, Ritvos O, Sandri M, Narkar V, Swann JR, Huber TB, Patel K. Enhanced exercise and regenerative capacity in a mouse model that violates size constraints of oxidative muscle fibres. eLife 2016; 5. [PMID: 27494364 PMCID: PMC4975572 DOI: 10.7554/elife.16940] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2016] [Accepted: 07/19/2016] [Indexed: 12/28/2022] Open
Abstract
A central tenet of skeletal muscle biology is the existence of an inverse relationship between the oxidative fibre capacity and its size. However, robustness of this relationship is unknown. We show that superimposition of Estrogen-related receptor gamma (Errγ) on the myostatin (Mtn) mouse null background (Mtn-/-/ErrγTg/+) results in hypertrophic muscle with a high oxidative capacity thus violating the inverse relationship between fibre size and oxidative capacity. We also examined the canonical view that oxidative muscle phenotype positively correlate with Satellite cell number, the resident stem cells of skeletal muscle. Surprisingly, hypertrophic fibres from Mtn-/-/ErrγTg/+ mouse showed satellite cell deficit which unexpectedly did not affect muscle regeneration. These observations 1) challenge the concept of a constraint between fibre size and oxidative capacity and 2) indicate the important role of the microcirculation in the regenerative capacity of a muscle even when satellite cell numbers are reduced. DOI:http://dx.doi.org/10.7554/eLife.16940.001
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Affiliation(s)
- Saleh Omairi
- School of Biological Sciences, University of Reading, Reading, United Kingdom
| | | | - Hans Degens
- School of Healthcare Science, Manchester Metropolitan University, Manchester, United Kingdom.,Lithuanian Sports University, Kaunas, Lithuania
| | - Oliver Kretz
- Renal Division, University Medical Center Freiburg, Freiburg, Germany.,Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Kenth-Arne Hansson
- Centre for Integrative Neuroplasticity, Department of Biosciences, University of Oslo, Oslo, Norway
| | - Andreas Våvang Solbrå
- Centre for Integrative Neuroplasticity, Department of Biosciences, University of Oslo, Oslo, Norway.,Department of Physics, University of Oslo, Oslo, Norway
| | - Jo C Bruusgaard
- Centre for Integrative Neuroplasticity, Department of Biosciences, University of Oslo, Oslo, Norway.,Department of Health Sciences, Kristiania University College, Oslo, Norway
| | - Barbara Joch
- Department of Neuroanatomy, University of Freiburg, Freiburg, Germany.,Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Roberta Sartori
- Venetian Institute of Molecular Medicine, University of Padua, Padua, Italy
| | - Natasa Giallourou
- Department of Food and Nutritional Sciences, University of Reading, Reading, United Kingdom
| | - Robert Mitchell
- School of Biological Sciences, University of Reading, Reading, United Kingdom
| | | | - Keith Foster
- School of Biological Sciences, University of Reading, Reading, United Kingdom
| | - Arja Pasternack
- Department of Bacteriology and Immunology, Haartman Institute, University of Helsinki, Helsinki, Finland
| | - Olli Ritvos
- Department of Bacteriology and Immunology, Haartman Institute, University of Helsinki, Helsinki, Finland
| | - Marco Sandri
- Venetian Institute of Molecular Medicine, University of Padua, Padua, Italy
| | - Vihang Narkar
- Institute of Molecular Medicine, University of Health Science Center, Houston, Texas
| | - Jonathan R Swann
- Department of Food and Nutritional Sciences, University of Reading, Reading, United Kingdom
| | - Tobias B Huber
- Renal Division, University Medical Center Freiburg, Freiburg, Germany.,Faculty of Medicine, University of Freiburg, Freiburg, Germany.,BIOSS Center for Biological Signalling Studies, Albert-Ludwigs-University Freiburg, Houston, Texas.,FRIAS, Freiburg Institute for Advanced Studies and Center for Biological System Analysis ZBSA, Freiburg, Germany
| | - Ketan Patel
- School of Biological Sciences, University of Reading, Reading, United Kingdom.,FRIAS, Freiburg Institute for Advanced Studies and Center for Biological System Analysis ZBSA, Freiburg, Germany
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32
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Paoli A, Pacelli QF, Cancellara P, Toniolo L, Moro T, Canato M, Miotti D, Neri M, Morra A, Quadrelli M, Reggiani C. Protein Supplementation Does Not Further Increase Latissimus Dorsi Muscle Fiber Hypertrophy after Eight Weeks of Resistance Training in Novice Subjects, but Partially Counteracts the Fast-to-Slow Muscle Fiber Transition. Nutrients 2016; 8:nu8060331. [PMID: 27258300 PMCID: PMC4924172 DOI: 10.3390/nu8060331] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2016] [Revised: 05/16/2016] [Accepted: 05/19/2016] [Indexed: 11/18/2022] Open
Abstract
The response to resistance training and protein supplementation in the latissimus dorsi muscle (LDM) has never been investigated. We investigated the effects of resistance training (RT) and protein supplementation on muscle mass, strength, and fiber characteristics of the LDM. Eighteen healthy young subjects were randomly assigned to a progressive eight-week RT program with a normal protein diet (NP) or high protein diet (HP) (NP 0.85 vs. HP 1.8 g of protein·kg−1·day−1). One repetition maximum tests, magnetic resonance imaging for cross-sectional muscle area (CSA), body composition, and single muscle fibers mechanical and phenotype characteristics were measured. RT induced a significant gain in strength (+17%, p < 0.0001), whole muscle CSA (p = 0.024), and single muscle fibers CSA (p < 0.05) of LDM in all subjects. Fiber isometric force increased in proportion to CSA (+22%, p < 0.005) and thus no change in specific tension occurred. A significant transition from 2X to 2A myosin expression was induced by training. The protein supplementation showed no significant effects on all measured outcomes except for a smaller reduction of 2X myosin expression. Our results suggest that in LDM protein supplementation does not further enhance RT-induced muscle fiber hypertrophy nor influence mechanic muscle fiber characteristics but partially counteracts the fast-to-slow fiber shift.
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Affiliation(s)
- Antonio Paoli
- Department of Biomedical Sciences, University of Padova, Padova 35131, Italy.
| | - Quirico F Pacelli
- Department of Biomedical Sciences, University of Padova, Padova 35131, Italy.
| | - Pasqua Cancellara
- Department of Biomedical Sciences, University of Padova, Padova 35131, Italy.
| | - Luana Toniolo
- Department of Biomedical Sciences, University of Padova, Padova 35131, Italy.
| | - Tatiana Moro
- Department of Biomedical Sciences, University of Padova, Padova 35131, Italy.
| | - Marta Canato
- Department of Biomedical Sciences, University of Padova, Padova 35131, Italy.
| | | | - Marco Neri
- AIFeM (Italian Medicine and Fitness Federation), Ravenna 48121, Italy.
| | - Aldo Morra
- Euganea Medica, Diagnostic Centre, Via Colombo 13, Albignasego (Padova) 35020, Italy.
| | - Marco Quadrelli
- Euganea Medica, Diagnostic Centre, Via Colombo 13, Albignasego (Padova) 35020, Italy.
| | - Carlo Reggiani
- Department of Biomedical Sciences, University of Padova, Padova 35131, Italy.
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33
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Dumont NA, Bentzinger CF, Sincennes MC, Rudnicki MA. Satellite Cells and Skeletal Muscle Regeneration. Compr Physiol 2016; 5:1027-59. [PMID: 26140708 DOI: 10.1002/cphy.c140068] [Citation(s) in RCA: 409] [Impact Index Per Article: 51.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Skeletal muscles are essential for vital functions such as movement, postural support, breathing, and thermogenesis. Muscle tissue is largely composed of long, postmitotic multinucleated fibers. The life-long maintenance of muscle tissue is mediated by satellite cells, lying in close proximity to the muscle fibers. Muscle satellite cells are a heterogeneous population with a small subset of muscle stem cells, termed satellite stem cells. Under homeostatic conditions all satellite cells are poised for activation by stimuli such as physical trauma or growth signals. After activation, satellite stem cells undergo symmetric divisions to expand their number or asymmetric divisions to give rise to cohorts of committed satellite cells and thus progenitors. Myogenic progenitors proliferate, and eventually differentiate through fusion with each other or to damaged fibers to reconstitute fiber integrity and function. In the recent years, research has begun to unravel the intrinsic and extrinsic mechanisms controlling satellite cell behavior. Nonetheless, an understanding of the complex cellular and molecular interactions of satellite cells with their dynamic microenvironment remains a major challenge, especially in pathological conditions. The goal of this review is to comprehensively summarize the current knowledge on satellite cell characteristics, functions, and behavior in muscle regeneration and in pathological conditions.
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Affiliation(s)
- Nicolas A Dumont
- Sprott Centre for Stem Cell Research, Ottawa Hospital Research Institute, Ottawa, Ontario, Canada
| | - C Florian Bentzinger
- Sprott Centre for Stem Cell Research, Ottawa Hospital Research Institute, Ottawa, Ontario, Canada.,Nestlé Institute of Health Sciences, EPFL Campus, Lausanne, Switzerland
| | - Marie-Claude Sincennes
- Sprott Centre for Stem Cell Research, Ottawa Hospital Research Institute, Ottawa, Ontario, Canada
| | - Michael A Rudnicki
- Sprott Centre for Stem Cell Research, Ottawa Hospital Research Institute, Ottawa, Ontario, Canada.,Faculty of Medicine, Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, Ontario, Canada
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34
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Frese S, Ruebner M, Suhr F, Konou TM, Tappe KA, Toigo M, Jung HH, Henke C, Steigleder R, Strissel PL, Huebner H, Beckmann MW, van der Keylen P, Schoser B, Schiffer T, Frese L, Bloch W, Strick R. Long-Term Endurance Exercise in Humans Stimulates Cell Fusion of Myoblasts along with Fusogenic Endogenous Retroviral Genes In Vivo. PLoS One 2015; 10:e0132099. [PMID: 26154387 PMCID: PMC4495930 DOI: 10.1371/journal.pone.0132099] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2015] [Accepted: 06/10/2015] [Indexed: 11/21/2022] Open
Abstract
Myogenesis is defined as growth, differentiation and repair of muscles where cell fusion of myoblasts to multinucleated myofibers is one major characteristic. Other cell fusion events in humans are found with bone resorbing osteoclasts and placental syncytiotrophoblasts. No unifying gene regulation for natural cell fusions has been found. We analyzed skeletal muscle biopsies of competitive cyclists for muscle-specific attributes and expression of human endogenous retrovirus (ERV) envelope genes due to their involvement in cell fusion of osteoclasts and syncytiotrophoblasts. Comparing muscle biopsies from post- with the pre-competitive seasons a significant 2.25-fold increase of myonuclei/mm fiber, a 2.38-fold decrease of fiber area/nucleus and a 3.1-fold decrease of satellite cells (SCs) occurred. We propose that during the pre-competitive season SC proliferation occurred following with increased cell fusion during the competitive season. Expression of twenty-two envelope genes of muscle biopsies demonstrated a significant increase of putative muscle-cell fusogenic genes Syncytin-1 and Syncytin-3, but also for the non-fusogenic erv3. Immunohistochemistry analyses showed that Syncytin-1 mainly localized to the sarcolemma of myofibers positive for myosin heavy-chain isotypes. Cellular receptors SLC1A4 and SLC1A5 of Syncytin-1 showed significant decrease of expression in post-competitive muscles compared with the pre-competitive season, but only SLC1A4 protein expression localized throughout the myofiber. Erv3 protein was strongly expressed throughout the myofiber, whereas envK1-7 localized to SC nuclei and myonuclei. Syncytin-1 transcription factors, PPARγ and RXRα, showed no protein expression in the myofiber, whereas the pCREB-Ser133 activator of Syncytin-1 was enriched to SC nuclei and myonuclei. Syncytin-1, Syncytin-3, SLC1A4 and PAX7 gene regulations along with MyoD1 and myogenin were verified during proliferating or actively-fusing human primary myoblast cell cultures, resembling muscle biopsies of cyclists. Myoblast treatment with anti-Synycytin-1 abrogated cell fusion in vitro. Our findings support functional roles for ERV envelope proteins, especially Syncytin-1, contributing to cell fusion of myotubes.
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Affiliation(s)
- Sebastian Frese
- Institute of Cardiovascular Research and Sport Medicine, Department of Molecular and Cellular Sport Medicine, German Sport University Cologne, Am Sportpark Muengersdorf, Cologne, Germany
- University Hospital Zurich, Department of Neurology, Frauenklinikstrasse, Zurich, Switzerland
- Institute of Human Movement Sciences and Sport, Exercise Physiology, ETH Zurich, Winterthurerstrasse, Zurich, Switzerland
| | - Matthias Ruebner
- Friedrich-Alexander University Erlangen-Nürnberg, University-Clinic Erlangen, Department of Gynaecology and Obstetrics, Laboratory for Molecular Medicine, Erlangen, Universitaetsstrasse, Erlangen, Germany
| | - Frank Suhr
- Institute of Cardiovascular Research and Sport Medicine, Department of Molecular and Cellular Sport Medicine, German Sport University Cologne, Am Sportpark Muengersdorf, Cologne, Germany
| | - Thierry M. Konou
- Institute of Cardiovascular Research and Sport Medicine, Department of Molecular and Cellular Sport Medicine, German Sport University Cologne, Am Sportpark Muengersdorf, Cologne, Germany
| | - Kim A. Tappe
- Institute of Cardiovascular Research and Sport Medicine, Department of Molecular and Cellular Sport Medicine, German Sport University Cologne, Am Sportpark Muengersdorf, Cologne, Germany
| | - Marco Toigo
- Institute of Human Movement Sciences and Sport, Exercise Physiology, ETH Zurich, Winterthurerstrasse, Zurich, Switzerland
- University of Zurich, Balgrist University Hospital, Department of Orthopaedics, Forchstrasse, Zurich, Switzerland
| | - Hans H. Jung
- University Hospital Zurich, Department of Neurology, Frauenklinikstrasse, Zurich, Switzerland
| | - Christine Henke
- Friedrich-Alexander University Erlangen-Nürnberg, University-Clinic Erlangen, Department of Gynaecology and Obstetrics, Laboratory for Molecular Medicine, Erlangen, Universitaetsstrasse, Erlangen, Germany
| | - Ruth Steigleder
- Friedrich-Alexander University Erlangen-Nürnberg, University-Clinic Erlangen, Department of Gynaecology and Obstetrics, Laboratory for Molecular Medicine, Erlangen, Universitaetsstrasse, Erlangen, Germany
| | - Pamela L. Strissel
- Friedrich-Alexander University Erlangen-Nürnberg, University-Clinic Erlangen, Department of Gynaecology and Obstetrics, Laboratory for Molecular Medicine, Erlangen, Universitaetsstrasse, Erlangen, Germany
| | - Hanna Huebner
- Friedrich-Alexander University Erlangen-Nürnberg, University-Clinic Erlangen, Department of Gynaecology and Obstetrics, Laboratory for Molecular Medicine, Erlangen, Universitaetsstrasse, Erlangen, Germany
| | - Matthias W. Beckmann
- Friedrich-Alexander University Erlangen-Nürnberg, University-Clinic Erlangen, Department of Gynaecology and Obstetrics, Laboratory for Molecular Medicine, Erlangen, Universitaetsstrasse, Erlangen, Germany
| | - Piet van der Keylen
- Institute of Anatomy, Friedrich-Alexander University of Erlangen-Nürnberg, Krankenhausstrasse, Erlangen, Germany
| | - Benedikt Schoser
- Ludwig Maximilian University Munich, Department of Neurology, Friedrich Baur Institute, Ziemssenstrasse, Munich, Germany
| | - Thorsten Schiffer
- German Sport University Cologne, Outpatient Clinic for Sports Traumatology and Public Health Consultation, Am Sportpark Muengersdorf, Cologne, Germany
| | - Laura Frese
- University Hospital and University Zurich, Division of Surgical Research, Raemistrasse, Zurich, Switzerland
| | - Wilhelm Bloch
- Institute of Cardiovascular Research and Sport Medicine, Department of Molecular and Cellular Sport Medicine, German Sport University Cologne, Am Sportpark Muengersdorf, Cologne, Germany
- The German Research Centre of Elite Sport, German Sport University Cologne, Am Sportpark Muengersdorf, Cologne, Germany
| | - Reiner Strick
- Friedrich-Alexander University Erlangen-Nürnberg, University-Clinic Erlangen, Department of Gynaecology and Obstetrics, Laboratory for Molecular Medicine, Erlangen, Universitaetsstrasse, Erlangen, Germany
- * E-mail:
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35
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Bagley JR. Fibre type-specific hypertrophy mechanisms in human skeletal muscle: potential role of myonuclear addition. J Physiol 2015; 592:5147-8. [PMID: 25448185 DOI: 10.1113/jphysiol.2014.282574] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Affiliation(s)
- James R Bagley
- Biochemistry and Molecular Exercise Physiology Laboratory, Center for Sport Performance, California State University, Fullerton, CA, USA
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36
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Blaauw B, Schiaffino S, Reggiani C. Mechanisms modulating skeletal muscle phenotype. Compr Physiol 2014; 3:1645-87. [PMID: 24265241 DOI: 10.1002/cphy.c130009] [Citation(s) in RCA: 155] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Mammalian skeletal muscles are composed of a variety of highly specialized fibers whose selective recruitment allows muscles to fulfill their diverse functional tasks. In addition, skeletal muscle fibers can change their structural and functional properties to perform new tasks or respond to new conditions. The adaptive changes of muscle fibers can occur in response to variations in the pattern of neural stimulation, loading conditions, availability of substrates, and hormonal signals. The new conditions can be detected by multiple sensors, from membrane receptors for hormones and cytokines, to metabolic sensors, which detect high-energy phosphate concentration, oxygen and oxygen free radicals, to calcium binding proteins, which sense variations in intracellular calcium induced by nerve activity, to load sensors located in the sarcomeric and sarcolemmal cytoskeleton. These sensors trigger cascades of signaling pathways which may ultimately lead to changes in fiber size and fiber type. Changes in fiber size reflect an imbalance in protein turnover with either protein accumulation, leading to muscle hypertrophy, or protein loss, with consequent muscle atrophy. Changes in fiber type reflect a reprogramming of gene transcription leading to a remodeling of fiber contractile properties (slow-fast transitions) or metabolic profile (glycolytic-oxidative transitions). While myonuclei are in postmitotic state, satellite cells represent a reserve of new nuclei and can be involved in the adaptive response.
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Affiliation(s)
- Bert Blaauw
- Department of Biomedical Sciences, University of Padova, Padova, Italy
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37
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Abstract
Many aspects of skeletal muscle biology are remarkably similar between mammals and tiny insects, and experimental models of mice and flies (Drosophila) provide powerful tools to understand factors controlling the growth, maintenance, degeneration (atrophy and necrosis), and regeneration of normal and diseased muscles, with potential applications to the human condition. This review compares the limb muscles of mice and the indirect flight muscles of flies, with respect to the mechanisms of adult myofiber formation, homeostasis, atrophy, hypertrophy, and the response to muscle degeneration, with some comment on myogenic precursor cells and common gene regulatory pathways. There is a striking similarity between the species for events related to muscle atrophy and hypertrophy, without contribution of any myoblast fusion. Since the flight muscles of adult flies lack a population of reserve myogenic cells (equivalent to satellite cells), this indicates that such cells are not required for maintenance of normal muscle function. However, since satellite cells are essential in postnatal mammals for myogenesis and regeneration in response to myofiber necrosis, the extent to which such regeneration might be possible in flight muscles of adult flies remains unclear. Common cellular and molecular pathways for both species are outlined related to neuromuscular disorders and to age-related loss of skeletal muscle mass and function (sarcopenia). The commonality of events related to skeletal muscles in these disparate species (with vast differences in size, growth duration, longevity, and muscle activities) emphasizes the combined value and power of these experimental animal models.
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38
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Liu F, Fry CS, Mula J, Jackson JR, Lee JD, Peterson CA, Yang L. Automated fiber-type-specific cross-sectional area assessment and myonuclei counting in skeletal muscle. J Appl Physiol (1985) 2013; 115:1714-24. [PMID: 24092696 DOI: 10.1152/japplphysiol.00848.2013] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Skeletal muscle is an exceptionally adaptive tissue that compromises 40% of mammalian body mass. Skeletal muscle functions in locomotion, but also plays important roles in thermogenesis and metabolic homeostasis. Thus characterizing the structural and functional properties of skeletal muscle is important in many facets of biomedical research, ranging from myopathies to rehabilitation sciences to exercise interventions aimed at improving quality of life in the face of chronic disease and aging. In this paper, we focus on automated quantification of three important morphological features of muscle: 1) muscle fiber-type composition; 2) muscle fiber-type-specific cross-sectional area, and 3) myonuclear content and location. We experimentally prove that the proposed automated image analysis approaches for fiber-type-specific assessments and automated myonuclei counting are fast, accurate, and reliable.
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Affiliation(s)
- Fujun Liu
- Division of Biomedical Informatics, Departments of Biostatistics and Computer Science, College of Public Health, University of Kentucky, Lexington, Kentucky
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39
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Myosin isoforms and contractile properties of single fibers of human Latissimus Dorsi muscle. BIOMED RESEARCH INTERNATIONAL 2013; 2013:249398. [PMID: 23971027 PMCID: PMC3736486 DOI: 10.1155/2013/249398] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/30/2013] [Accepted: 07/05/2013] [Indexed: 12/03/2022]
Abstract
The aim of our study was to investigate fiber type distribution and contractile characteristics of Latissimus Dorsi muscle (LDM). Samples were collected from 18 young healthy subjects (9 males and 9 females) through percutaneous fine needle muscle biopsy. The results showed a predominance of fast myosin heavy chain isoforms (MyHC) with 42% of MyHC 2A and 25% of MyHC 2X, while MyHC 1 represented only 33%. The unbalance toward fast isoforms was even greater in males (71%) than in females (64%). Fiber type distribution partially reflected MyHC isoform distribution with 28% type 1/slow fibers and 5% hybrid 1/2A fibers, while fast fibers were divided into 30% type 2A, 31% type A/X, 4% type X, and 2% type 1/2X. Type 1/slow fibers were not only less abundant but also smaller in cross-sectional area than fast fibers. During maximal isometric contraction, type 1/slow fibers developed force and tension significantly lower than the two major groups of fast fibers. In conclusion, the predominance of fast fibers and their greater size and strength compared to slow fibers reveal that LDM is a muscle specialized mainly in phasic and powerful activity. Importantly, such specialization is more pronounced in males than in females.
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40
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Partridge TA. The mdx mouse model as a surrogate for Duchenne muscular dystrophy. FEBS J 2013; 280:4177-86. [PMID: 23551987 DOI: 10.1111/febs.12267] [Citation(s) in RCA: 133] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2013] [Revised: 03/18/2013] [Accepted: 03/19/2013] [Indexed: 01/06/2023]
Abstract
Research into fundamental principles and the testing of therapeutic hypotheses for treatment of human disease is commonly performed on mouse models of human diseases. Although this is often the only practicable approach, it carries a number of caveats arising from differences between the two species. This review focuses on the example of skeletal muscle disease, in particular muscular dystrophy, to identify some of the principal classes of obstacles to translation of data from mouse to humans. Of these, the difference in scale is one of the most commonly ignored, and is of particular interest because it has quite major repercussions for evaluation of some classes of intervention and of outcome criteria, while having comparatively little bearing on others. Likewise, inter-species differences and similarities in cell and molecular biological mechanisms underlying development, growth and response to pathological processes should be considered on an individual basis. An awareness of such distinctions is crucial if we are to avoid misjudging the likely applicability to humans of results obtained on mouse models.
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Affiliation(s)
- Terence A Partridge
- Children's National Medical Center, Center for Genetic Medicine, Washington, DC 20010, USA.
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41
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Absence of metabolic rate allometry in an ex vivo model of mammalian skeletal muscle. Comp Biochem Physiol A Mol Integr Physiol 2012; 162:157-62. [DOI: 10.1016/j.cbpa.2012.01.022] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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42
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Little SC, Biesiadecki BJ, Kilic A, Higgins RSD, Janssen PML, Davis JP. The rates of Ca2+ dissociation and cross-bridge detachment from ventricular myofibrils as reported by a fluorescent cardiac troponin C. J Biol Chem 2012; 287:27930-40. [PMID: 22718768 DOI: 10.1074/jbc.m111.337295] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
The rate-limiting step of cardiac muscle relaxation has been proposed to reside in the myofilament. Both the rates of cross-bridge detachment and Ca(2+) dissociation from troponin C (TnC) have been hypothesized to rate-limit myofilament inactivation. In this study we used a fluorescent TnC to measure both the rate of Ca(2+) dissociation from TnC and the rate of cross-bridge detachment from several different species of ventricular myofibrils. The fluorescently labeled TnC was sensitive to both Ca(2+) dissociation and cross-bridge detachment at low Ca(2+) (presence of EGTA), allowing for a direct comparison between the two proposed rates of myofilament inactivation. Unlike Ca(2+) dissociation from TnC, cross-bridge detachment varied in myofibrils from different species and was rate-limited by ADP release. At subphysiological temperatures (<20 °C), the rate of Ca(2+) dissociation from TnC was faster than the rate of cross-bridge detachment in the presence of ADP. These results support the hypothesis that cross-bridge detachment rate-limits relaxation. However, Ca(2+) dissociation from TnC was not as temperature-sensitive as cross-bridge detachment. At a near physiological temperature (35 °C) and ADP, the rate of cross-bridge detachment may actually be faster than the rate of Ca(2+) dissociation. This provides evidence that there may not be a simple, single rate-limiting step of myofilament inactivation.
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Affiliation(s)
- Sean C Little
- Department of Physiology and Cell Biology, College of Medicine, The Ohio State University, Columbus, Ohio 43210, USA
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43
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Agley CC, Velloso CP, Lazarus NR, Harridge SDR. An image analysis method for the precise selection and quantitation of fluorescently labeled cellular constituents: application to the measurement of human muscle cells in culture. J Histochem Cytochem 2012; 60:428-38. [PMID: 22511600 DOI: 10.1369/0022155412442897] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/07/2022] Open
Abstract
The accurate measurement of the morphological characteristics of cells with nonuniform conformations presents difficulties. We report here a straightforward method using immunofluorescent staining and the commercially available imaging program Adobe Photoshop, which allows objective and precise information to be gathered on irregularly shaped cells. We have applied this measurement technique to the analysis of human muscle cells and their immunologically marked intracellular constituents, as these cells are prone to adopting a highly branched phenotype in culture. Use of this method can be used to overcome many of the long-standing limitations of conventional approaches for quantifying muscle cell size in vitro. In addition, wider applications of Photoshop as a quantitative and semiquantitative tool in immunocytochemistry are explored.
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Affiliation(s)
- Chibeza C Agley
- Centre of Human and Aerospace Physiological Sciences, School of Biomedical Sciences, King's College London, London, United Kingdom
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44
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Qaisar R, Renaud G, Morine K, Barton ER, Sweeney HL, Larsson L. Is functional hypertrophy and specific force coupled with the addition of myonuclei at the single muscle fiber level? FASEB J 2011; 26:1077-85. [PMID: 22125316 DOI: 10.1096/fj.11-192195] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Muscle force is typically proportional to muscle size, resulting in constant force normalized to muscle fiber cross-sectional area (specific force). Mice overexpressing insulin-like growth factor-1 (IGF-1) exhibit a proportional gain in muscle force and size, but not the myostatin-deficient mice. In an attempt to explore the role of the cytoplasmic volume supported by individual myonuclei [myonuclear domain (MND) size] on functional capacity of skeletal muscle, we have investigated specific force in relation to MND and the content of the molecular motor protein, myosin, at the single muscle fiber level from myostatin-knockout (Mstn(-/-)) and IGF-1-overexpressing (mIgf1(+/+)) mice. We hypothesize that the addition of extra myonuclei is a prerequisite for maintenance of specific force during muscle hypertrophy. A novel algorithm was used to measure individual MNDs in 3 dimensions along the length of single muscle fibers from the fast-twitch extensor digitorum longus and the slow-twitch soleus muscle. A significant effect of the size of individual MNDs in hypertrophic muscle fibers on both specific force and myosin content was observed. This effect was muscle cell type specific and suggested there is a critical volume individual myonuclei can support efficiently. The large MNDs found in fast muscles of Mstn(-/-) mice were correlated with the decrement in specific force and myosin content in Mstn(-/-) muscles. Thus, myostatin inhibition may not be able to maintain the appropriate MND for optimal function.
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Affiliation(s)
- Rizwan Qaisar
- Department of Neuroscience, Uppsala University, SE-751 85 Uppsala, Sweden
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45
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Abstract
Vascular endothelial growth factor (VEGF) is a key regulator of angiogenesis – the growth of new microvessels from existing microvasculature. Angiogenesis is a complex process involving numerous molecular species, and to better understand it, a systems biology approach is necessary. In vivo preclinical experiments in the area of angiogenesis are typically performed in mouse models; this includes drug development targeting VEGF. Thus, to quantitatively interpret such experimental results, a computational model of VEGF distribution in the mouse can be beneficial. In this paper, we present an in silico model of VEGF distribution in mice, determine model parameters from existing experimental data, conduct sensitivity analysis, and test the validity of the model. The multiscale model is comprised of two compartments: blood and tissue. The model accounts for interactions between two major VEGF isoforms (VEGF120 and VEGF164) and their endothelial cell receptors VEGFR-1, VEGFR-2, and co-receptor neuropilin-1. Neuropilin-1 is also expressed on the surface of parenchymal cells. The model includes transcapillary macromolecular permeability, lymphatic transport, and macromolecular plasma clearance. Simulations predict that the concentration of unbound VEGF in the tissue is approximately 50-fold greater than in the blood. These concentrations are highly dependent on the VEGF secretion rate. Parameter estimation was performed to fit the simulation results to available experimental data, and permitted the estimation of VEGF secretion rate in healthy tissue, which is difficult to measure experimentally. The model can provide quantitative interpretation of preclinical animal data and may be used in conjunction with experimental studies in the development of pro- and anti-angiogenic agents. The model approximates the normal tissue as skeletal muscle and includes endothelial cells to represent the vasculature. As the VEGF system becomes better characterized in other tissues and cell types, the model can be expanded to include additional compartments and vascular elements.
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Priester C, Morton LC, Kinsey ST, Watanabe WO, Dillaman RM. Growth patterns and nuclear distribution in white muscle fibers from black sea bass, Centropristis striata: evidence for the influence of diffusion. ACTA ACUST UNITED AC 2011; 214:1230-9. [PMID: 21430198 DOI: 10.1242/jeb.053199] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
This study investigated the influence of fiber size on the distribution of nuclei and fiber growth patterns in white muscle of black sea bass, Centropristis striata, ranging in body mass from 0.45 to 4840 g. Nuclei were counted in 1 μm optical sections using confocal microscopy of DAPIand Acridine-Orange-stained muscle fibers. Mean fiber diameter increased from 36±0.87 μm in the 0.45 g fish to 280±5.47 μm in the 1885 g fish. Growth beyond 2000 g triggered the recruitment of smaller fibers, thus significantly reducing mean fiber diameter. Nuclei in the smaller fibers were exclusively subsarcolemmal (SS), whereas in larger fibers nuclei were more numerous and included intermyofibrillar (IM) nuclei. There was a significant effect of body mass on nuclear domain size (F=118.71, d.f.=3, P<0.0001), which increased to a maximum in fish of medium size (282-1885 g) and then decreased in large fish (>2000 g). Although an increase in the number of nuclei during fiber growth can help preserve the myonuclear domain, the appearance of IM nuclei during hypertrophic growth seems to be aimed at maintaining short effective diffusion distances for nuclear substrates and products. If only SS nuclei were present throughout growth, the diffusion distance would increase in proportion to the radius of the fibers. These observations are consistent with the hypothesis that changes in nuclear distribution and fiber growth patterns are mechanisms for avoiding diffusion limitation during animal growth.
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Affiliation(s)
- Carolina Priester
- Department of Biology and Marine Biology, University of North Carolina Wilmington, 601 South College Road, Wilmington, NC 28403, USA.
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Kawai M, Kuwano A, Hiraga A, Miyata H. Relationships between myonuclear domain size and fibre properties in the muscles of Thoroughbred horses. Equine Vet J 2011:311-6. [PMID: 21059023 DOI: 10.1111/j.2042-3306.2010.00236.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
REASONS FOR PERFORMING STUDY The myonuclear domain (MND) is the region of cytoplasm governed by a single myonucleus. Myonuclear domain size is an important factor for muscle fibre plasticity because each myonucleus has limitations in the capacity of protein synthesis. Previous studies have demonstrated that differences in MND size exist in different fibre types in several species, including horses. OBJECTIVES To understand the basic mechanism of muscle plasticity, the relationships between MND size, muscle fibre type population and metabolic properties of skeletal muscles throughout the whole body in Thoroughbred horses were examined. METHODS Post mortem samples were taken from 20 muscles in 3 Thoroughbred horses aged 3-5 years of age. Fibre type population was determined on serial cross sections of each muscle sample, stained for monoclonal antibodies to each myosin heavy chain isoform. Oxidative (succinic dehydrogenase; SDH) and glycolytic (phosphofructokinase; PFK) enzyme activities were determined spectrophotometrically in each muscle sample. Furthermore, 30 single fibres were isolated from each muscle under stereomicroscopy and then fibre volume and myonuclear number for a given length analysed under confocal microscopy. The MND size of each single fibre was measured after normalisation of sarcomere length to 2.8 µm by staining with membrane-specific dye. RESULTS Immunohistochemical staining indicated that soleus, vastus lateralis and gluteus medius muscles had the highest percentage of type I, IIa and IIx muscle fibre, respectively. Biochemical analysis indicated highest activities of SDH and PFK in diaphragm and longissimus lumborum muscles, respectively. MNDs were largest in the splenius muscle and smallest in the soleus and masseter muscles. Myonuclear domain size is significantly related to type I muscle fibre population, but not to SDH activities of the muscles. CONCLUSION The MND size of muscle fibre depends on fibre type population rather than mitochondrial enzyme activities.
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Affiliation(s)
- M Kawai
- Biological Science, Graduate School of Medicine, Yamaguchi University, Yoshida, Yamaguchi, Japan
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Kocha KM, Genge CE, Moyes CD. Origins of interspecies variation in mammalian muscle metabolic enzymes. Physiol Genomics 2011; 43:873-83. [PMID: 21586671 DOI: 10.1152/physiolgenomics.00025.2011] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Do the transcriptional mechanisms that control an individual's mitochondrial content, PGC1α (peroxisome proliferator-activated receptor γ coactivator-1α) and NRF1 (nuclear respiratory factor-1), also cause differences between species? We explored the determinants of cytochrome c oxidase (COX) activities in muscles from 12 rodents differing 1,000-fold in mass. Hindlimb muscles differed in scaling patterns from isometric (soleus, gastrocnemius) to allometric (tibialis anterior, scaling coefficient = -0.16). Consideration of myonuclear domain reduced the differences within species, but interspecies differences remained. For tibialis anterior, there was no significant scaling relationship in mRNA/g for COX4-1, PGC1α, or NRF1, yet COX4-1 mRNA/g was a good predictor of COX activity (r(2) = 0.55), PGC1α and NRF1 mRNA correlated with each other (r(2) = 0.42), and both could predict COX4-1 mRNA (r(2) = 0.48 and 0.52) and COX activity (r(2) = 0.55 and 0.49). This paradox was resolved by multivariate analysis, which explained 90% of interspecies variation, about equally partitioned between mass effects and PGC1α (or NRF1) mRNA levels, independent of mass. To explore the determinants of PGC1α mRNA, we analyzed 52 mammalian PGC1α proximal promoters and found no size dependence in regulatory element distribution. Likewise, the activity of PGC1α promoter reporter genes from 30 mammals showed no significant relationship with body mass. Collectively, these studies suggest that not all muscles scale equivalently, but for those that show allometric scaling, transcriptional regulation of the master regulators, PGC1α and NRF1, does not account for scaling patterns, though it does contribute to interspecies differences in COX activities independent of mass.
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Affiliation(s)
- K M Kocha
- Department of Biology, Queen's University, Kingston, Ontario, Canada
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Abstract
PURPOSE OF REVIEW Current knowledge on satellite cells in relation to suggested mechanisms of loss of muscle mass and strength, induction of fat infiltration, and countermeasures is highlighted. RECENT FINDINGS Consensus on the definition of sarcopenia and sarcopenic obesity is proposed. Human satellite cell heterogeneity has now unequivocally been verified in situ as well as an adipogenic potential, though in mice other muscle stem cells are the hot topic to induce adipogenesis upon muscle damage. Inflammation, oxidative stress, proteolytic degradation, and nuclear apoptosis are discussed as pathogenetic mechanisms of sarcopenia, although little evidence exists that they are important in human muscle. In rodents, exercise-induced muscle injury is a hallmark for sequential events leading to muscle fiber necrosis and sarcopenia. Exercise in humans, on the contrary, is the key event to countermeasure sarcopenia. Cautions to extrapolate observation in rodents to explain human conditions have been presented. SUMMARY Human satellite cells are indispensable for maintenance of human muscle mass, but their implications in the pathogenesis of sarcopenia and sarcopenic obesity are still under debate. Nevertheless, satellite cell activation upon exercise seems unequivocally together with adequate nutrition to be the most effective countermeasure for sarcopenia and sarcopenic obesity.
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Affiliation(s)
- Lars-Eric Thornell
- Department of Integrative Medical Biology, Section for Anatomy, Umea University, Umea, Sweden.
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Fiaccavento R, Carotenuto F, Vecchini A, Binaglia L, Forte G, Capucci E, Maccari AM, Minieri M, Di Nardo P. An omega-3 fatty acid-enriched diet prevents skeletal muscle lesions in a hamster model of dystrophy. THE AMERICAN JOURNAL OF PATHOLOGY 2010; 177:2176-84. [PMID: 20829440 DOI: 10.2353/ajpath.2010.100174] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Currently, despite well-known mutational causes, a universal treatment for neuromuscular disorders is still lacking, and current therapeutic efforts are mainly restricted to symptomatic treatments. In the present study, δ-sarcoglycan-null dystrophic hamsters were fed a diet enriched in flaxseed-derived ω3 α-linolenic fatty acid from weaning until death. α-linolenic fatty acid precluded the dystrophic degeneration of muscle morphology and function. In fact, in dystrophic animals fed flaxseed-derived α-linolenic fatty acid, the histological appearance of the muscular tissue was improved, the proliferation of interstitial cells was decreased, and the myogenic differentiation originated new myocytes to repair the injured muscle. In addition, muscle myofibers were larger and cell membrane integrity was preserved, as witnessed by the correct localization of α-, β-, and γ-sarcoglycans and α-dystroglycan. Furthermore, the cytoplasmic accumulation of both β-catenin and caveolin-3 was abolished in dystrophic hamster muscle fed α-linolenic fatty acid versus control animals fed standard diet, while α-myosin heavy chain was expressed at nearly physiological levels. These findings, obtained by dietary intervention only, introduce a novel concept that provides evidence that the modulation of the plasmalemma lipid profile could represent an efficacious strategy to ameliorate human muscular dystrophy.
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Affiliation(s)
- Roberta Fiaccavento
- Laboratorio di Cardiologia Molecolare e Cellulare, Dipartimento di Medicina Interna, Università di Roma Tor Vergata, Via Montpellier, 1, 00133 Roma, Italy
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