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Dugdale HF, Levy Y, Jungbluth H, Oldfors A, Ochala J. Aberrant myonuclear domains and impaired myofiber contractility despite marked hypertrophy in MYMK-related, Carey-Fineman-Ziter Syndrome. Acta Neuropathol Commun 2024; 12:80. [PMID: 38790073 PMCID: PMC11127446 DOI: 10.1186/s40478-024-01783-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2024] [Accepted: 04/10/2024] [Indexed: 05/26/2024] Open
Abstract
Carey Fineman Ziter Syndrome (CFZS) is a rare autosomal recessive disease caused by mutations in the MYMK locus which encodes the protein, myomaker. Myomaker is essential for fusion and concurrent myonuclei donation of muscle progenitors during growth and development. Strikingly, in humans, MYMK mutations appear to prompt myofiber hypertrophy but paradoxically, induce generalised muscle weakness. As the underlying cellular mechanisms remain unexplored, the present study aimed to gain insights by combining myofiber deep-phenotyping and proteomic profiling. Hence, we isolated individual muscle fibers from CFZS patients and performed mechanical, 3D morphological and proteomic analyses. Myofibers from CFZS patients were ~ 4x larger than controls and possessed ~ 2x more myonuclei than those from healthy subjects, leading to disproportionally larger myonuclear domain volumes. These greater myonuclear domain sizes were accompanied by smaller intrinsic cellular force generating-capacities in myofibers from CFZS patients than in control muscle cells. Our complementary proteomic analyses indicated remodelling in 233 proteins particularly those associated with cellular respiration. Overall, our findings suggest that myomaker is somewhat functional in CFZS patients, but the associated nuclear accretion may ultimately lead to non-functional hypertrophy and altered energy-related mechanisms in CFZS patients. All of these are likely contributors of the muscle weakness experienced by CFZS patients.
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Affiliation(s)
- Hannah F Dugdale
- School of Sport, Exercise and Health Sciences, Loughborough University, Loughborough, UK
- Centre for Human and Applied Physiological Sciences, School of Basic and Medical Biosciences, Faculty of Life Sciences and Medicine, King's College London, London, UK
| | - Yotam Levy
- Centre for Human and Applied Physiological Sciences, School of Basic and Medical Biosciences, Faculty of Life Sciences and Medicine, King's College London, London, UK
| | - Heinz Jungbluth
- Randall Centre for Cell and Molecular Biophysics, Muscle Signalling Section, Faculty of Life Sciences and Medicine (FoLSM), King's College London, London, UK
- Department of Paediatric Neurology, Neuromuscular Service, Evelina Children's Hospital, Guy's and St Thomas' Hospital NHS Foundation Trust, London, UK
| | - Anders Oldfors
- Department of Laboratory Medicine, University of Gothenburg, Gothenburg, Sweden
| | - Julien Ochala
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.
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2
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Buddell T, Purdy AL, Patterson M. The genetics of cardiomyocyte polyploidy. Curr Top Dev Biol 2024; 156:245-295. [PMID: 38556425 DOI: 10.1016/bs.ctdb.2024.01.008] [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] [Indexed: 04/02/2024]
Abstract
The regulation of ploidy in cardiomyocytes is a complex and tightly regulated aspect of cardiac development and function. Cardiomyocyte ploidy can range from diploid (2N) to 8N or even 16N, and these states change during key stages of development and disease progression. Polyploidization has been associated with cellular hypertrophy to support normal growth of the heart, increased contractile capacity, and improved stress tolerance in the heart. Conversely, alterations to ploidy also occur during cardiac pathogenesis of diseases, such as ischemic and non-ischemic heart failure and arrhythmia. Therefore, understanding which genes control and modulate cardiomyocyte ploidy may provide mechanistic insight underlying cardiac growth, regeneration, and disease. This chapter summarizes the current knowledge regarding the genes involved in the regulation of cardiomyocyte ploidy. We discuss genes that have been directly tested for their role in cardiomyocyte polyploidization, as well as methodologies used to identify ploidy alterations. These genes encode cell cycle regulators, transcription factors, metabolic proteins, nuclear scaffolding, and components of the sarcomere, among others. The general physiological and pathological phenotypes in the heart associated with the genetic manipulations described, and how they coincide with the respective cardiomyocyte ploidy alterations, are further discussed in this chapter. In addition to being candidates for genetic-based therapies for various cardiac maladies, these genes and their functions provide insightful evidence regarding the purpose of widespread polyploidization in cardiomyocytes.
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Affiliation(s)
- Tyler Buddell
- Cardiovascular Center, Medical College of Wisconsin, Milwaukee, WI, United States; Department of Cell Biology, Neurobiology, and Anatomy, Medical College of Wisconsin, Milwaukee, WI, United States
| | - Alexandra L Purdy
- Department of Cell Biology, Neurobiology, and Anatomy, Medical College of Wisconsin, Milwaukee, WI, United States
| | - Michaela Patterson
- Cardiovascular Center, Medical College of Wisconsin, Milwaukee, WI, United States; Department of Cell Biology, Neurobiology, and Anatomy, Medical College of Wisconsin, Milwaukee, WI, United States.
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3
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Aman F, El Khatib E, AlNeaimi A, Mohamed A, Almulla AS, Zaidan A, Alshafei J, Habbal O, Eldesouki S, Qaisar R. Is the myonuclear domain ceiling hypothesis dead? Singapore Med J 2023; 64:415-422. [PMID: 34544215 PMCID: PMC10395806 DOI: 10.11622/smedj.2021103] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2020] [Accepted: 09/01/2020] [Indexed: 11/18/2022]
Abstract
Muscle fibres are multinuclear cells, and the cytoplasmic territory where a single myonucleus controls transcriptional activity is called the myonuclear domain (MND). MND size shows flexibility during muscle hypertrophy. The MND ceiling hypothesis states that hypertrophy results in the expansion of MND size to an upper limit or MND ceiling, beyond which additional myonuclei via activation of satellite cells are required to support further growth. However, the debate about the MND ceiling hypothesis is far from settled, and various studies show conflicting results about the existence or otherwise of MND ceiling in hypertrophy. The aim of this review is to summarise the literature about the MND ceiling in various settings of hypertrophy and discuss the possible factors contributing to a discrepancy in the literature. We conclude by describing the physiological and clinical significance of the MND ceiling limit in the muscle adaptation process in various physiological and pathological conditions.
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Affiliation(s)
- Ferdos Aman
- Department of Basic Medical Sciences, College of Medicine, University of Sharjah, Sharjah, United Arab Emirates
| | - Eman El Khatib
- Department of Basic Medical Sciences, College of Medicine, University of Sharjah, Sharjah, United Arab Emirates
| | - Alanood AlNeaimi
- Department of Basic Medical Sciences, College of Medicine, University of Sharjah, Sharjah, United Arab Emirates
| | - Ahmed Mohamed
- Department of Basic Medical Sciences, College of Medicine, University of Sharjah, Sharjah, United Arab Emirates
| | - Alya Sultan Almulla
- Department of Basic Medical Sciences, College of Medicine, University of Sharjah, Sharjah, United Arab Emirates
| | - Amna Zaidan
- Department of Basic Medical Sciences, College of Medicine, University of Sharjah, Sharjah, United Arab Emirates
| | - Jana Alshafei
- Department of Basic Medical Sciences, College of Medicine, University of Sharjah, Sharjah, United Arab Emirates
| | - Omar Habbal
- Department of Basic Medical Sciences, College of Medicine, University of Sharjah, Sharjah, United Arab Emirates
| | - Salma Eldesouki
- Department of Basic Medical Sciences, College of Medicine, University of Sharjah, Sharjah, United Arab Emirates
| | - Rizwan Qaisar
- Department of Basic Medical Sciences, College of Medicine, University of Sharjah, Sharjah, United Arab Emirates
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Miyazaki M, Sawada A, Sawamura D, Yoshida S. Decreased insulin-like growth factor-1 expression in response to mechanical loading is associated with skeletal muscle anabolic resistance in cancer cachexia. Growth Horm IGF Res 2023; 69-70:101536. [PMID: 37229943 DOI: 10.1016/j.ghir.2023.101536] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/02/2022] [Revised: 05/07/2023] [Accepted: 05/16/2023] [Indexed: 05/27/2023]
Abstract
OBJECTIVE Cachexia is a systemic metabolic syndrome characterized by loss of body weight and skeletal muscle mass during chronic wasting diseases, such as cancer. Skeletal muscle in cancer cachexia is less responsive to anabolic factors including mechanical loading; however, the precise molecular mechanism is largely unknown. In this study, we examined the underlying mechanism of anabolic resistance in skeletal muscle in a cancer cachexia model. METHODS CD2F1 mice (male, 8 weeks old) were subcutaneously transplanted (1 × 106 cells per mouse) with a mouse colon cancer-derived cell line (C26) as a model of cancer cachexia. Mechanical overload of the plantaris muscle by synergist tenotomy was performed during the 2nd week and the plantaris muscle was sampled at the 4th week following C26 transplantation. RESULTS The hypertrophic response of skeletal muscle (increased skeletal muscle weight/protein synthesis efficiency and activation of mechanistic target of rapamycin complex 1 signaling) associated with mechanical overload was significantly suppressed during cancer cachexia. Screening of gene expression profile and pathway analysis using microarray revealed that blunted muscle protein synthesis was associated with cancer cachexia and was likely induced by downregulation of insulin-like growth factor-1 (IGF-1) and impaired activation of IGF-1-dependent signaling. CONCLUSIONS These observations indicate that cancer cachexia induces resistance to muscle protein synthesis, which may be a factor for inhibiting the anabolic adaptation of skeletal muscle to physical exercise in cancer patients.
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Affiliation(s)
- Mitsunori Miyazaki
- Department of Integrative Physiology, Graduate School of Biomedical and Health Sciences, Hiroshima University, Japan; Department of Physical Therapy, School of Rehabilitation Sciences, Health Sciences University of Hokkaido, Japan.
| | - Atsushi Sawada
- Department of Physical Therapy, School of Rehabilitation Sciences, Health Sciences University of Hokkaido, Japan
| | - Daisuke Sawamura
- Department of Rehabilitation Science, Faculty of Health Sciences, Hokkaido University, Japan
| | - Susumu Yoshida
- Department of Physical Therapy, School of Rehabilitation Sciences, Health Sciences University of Hokkaido, Japan
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5
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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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6
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Qaisar R, Ustrana S, Muhammad T, Shah I. Sarcopenia in pulmonary diseases is associated with elevated sarcoplasmic reticulum stress and myonuclear disorganization. Histochem Cell Biol 2021; 157:93-105. [PMID: 34665327 DOI: 10.1007/s00418-021-02043-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/06/2021] [Indexed: 02/07/2023]
Abstract
Chronic obstructive pulmonary disease (COPD) is frequently associated with age-related muscle loss or sarcopenia. However, the exact molecular mechanism of muscle loss in COPD remains elusive. We investigated the association of chronic dysregulation of sarcoplasmic reticulum (SR) protein homeostasis (a condition called SR stress) and myonuclear disorganization with sarcopenia in patients with COPD. Markers of SR stress and their downstream consequences, including apoptosis and inflammation, were upregulated in patients with COPD. The maximal SR Ca2+ ATPase (SERCA) activity was significantly reduced in advanced COPD as compared to healthy controls. Single muscle fiber diameter and cytoplasmic domain per myonucleus were significantly smaller in patients with advanced COPD than in healthy controls. Increased disruption of myonuclear organization was found in the COPD patients as compared to healthy controls. These changes in SR dysfunction were accompanied by elevated global levels of oxidative stress, including lipid peroxidation and mitochondrial reactive oxygen species (ROS) production. Altogether, our data suggest that muscle weakness in advanced COPD is in part associated with the disruption of SR protein and calcium homeostasis and their pathological consequences.
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Affiliation(s)
- Rizwan Qaisar
- Basic Medical Sciences, College of Medicine, University of Sharjah, 27272, Sharjah, United Arab Emirates.
| | - Shahjahan Ustrana
- Department of Biochemistry, Gomal Medical College, Dera Ismail Khan, 29050, Pakistan
| | - Tahir Muhammad
- Department of Biochemistry, Gomal Medical College, Dera Ismail Khan, 29050, Pakistan
| | - Islam Shah
- Al-Qassimi Hospital, 27272, Sharjah, United Arab Emirates
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7
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Antimyostatin Treatment in Health and Disease: The Story of Great Expectations and Limited Success. Cells 2021; 10:cells10030533. [PMID: 33802348 PMCID: PMC8001237 DOI: 10.3390/cells10030533] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2021] [Revised: 02/24/2021] [Accepted: 02/26/2021] [Indexed: 12/14/2022] Open
Abstract
In the past 20 years, myostatin, a negative regulator of muscle mass, has attracted attention as a potential therapeutic target in muscular dystrophies and other conditions. Preclinical studies have shown potential for increasing muscular mass and ameliorating the pathological features of dystrophic muscle by the inhibition of myostatin in various ways. However, hardly any clinical trials have proven to translate the promising results from the animal models into patient populations. We present the background for myostatin regulation, clinical and preclinical results and discuss why translation from animal models to patients is difficult. Based on this, we put the clinical relevance of future antimyostatin treatment into perspective.
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8
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Monti E, Toniolo L, Marcucci L, Bondì M, Martellato I, Šimunič B, Toninello P, Franchi MV, Narici MV, Reggiani C. Are muscle fibres of body builders intrinsically weaker? A comparison with single fibres of aged-matched controls. Acta Physiol (Oxf) 2021; 231:e13557. [PMID: 32921001 DOI: 10.1111/apha.13557] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2020] [Revised: 08/21/2020] [Accepted: 09/03/2020] [Indexed: 12/17/2022]
Abstract
AIM Skeletal muscles of Body Builders (BB) represent an interesting model to study muscle mass gains in response to high volume resistance training. It is debated whether muscle contractile performance improves in proportion to mass. Here, we aim to assess whether muscle hypertrophy does not occur at the expense of performance. METHODS Six BB and Six untrained controls (CTRL) were recruited. Cross-sectional area (CSA) and maximum voluntary contraction (MVC) of quadriceps femoris muscle (QF) and CSA and architecture of vastus lateralis (VL) were determined. Moreover, a biopsy was taken from VL mid-portion and single fibres were analysed. RESULTS QF CSA and MVC were 32% (n.s., P = .052) and 58% (P = .009) higher in BB than in CTRL, respectively. VL CSA was 37% higher in BB (P = .030). Fast 2A fibres CSA was 24% (P = .048) greater in BB than in CTRL, when determined in immunostained sections of biopsy samples. Single permeabilized fast fibres CSA was 37% (n.s., P = .052) higher in BB than in CTRL, and their force was slightly higher in BB (n.s.), while specific tension (P0 ) was 19% (P = .024) lower. The lower P0 was not explained either by lower myosin content or by impaired calcium diffusion. Conversely, the swelling caused by skinning-induced permeabilization was different and, when used to correct P0 , differences between populations disappeared. CONCLUSIONS The results show that high degree of muscle hypertrophy is not detrimental for force generation capacity, as increases in fibre size and force are strictly proportional once the differential swelling response is accounted for.
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Affiliation(s)
- Elena Monti
- Department of Biomedical Sciences University of Padova Padova Italy
| | - Luana Toniolo
- Department of Biomedical Sciences University of Padova Padova Italy
| | - Lorenzo Marcucci
- Department of Biomedical Sciences University of Padova Padova Italy
| | - Michela Bondì
- Department of Biomedical Sciences University of Padova Padova Italy
| | - Ivan Martellato
- Department of Biomedical Sciences University of Padova Padova Italy
| | - Bostjan Šimunič
- Science and Research Centre Koper Institute for Kinesiology Research Koper Slovenia
| | - Paolo Toninello
- Clinic of Plastic Surgery Padova University Hospital Padova Italy
| | | | - Marco V. Narici
- Department of Biomedical Sciences University of Padova Padova Italy
- Science and Research Centre Koper Institute for Kinesiology Research Koper Slovenia
- CIR‐MYO Myology Centre Department of Biomedical Sciences University of Padua Padova Italy
| | - Carlo Reggiani
- Department of Biomedical Sciences University of Padova Padova Italy
- Science and Research Centre Koper Institute for Kinesiology Research Koper Slovenia
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9
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Cramer AAW, Prasad V, Eftestøl E, Song T, Hansson KA, Dugdale HF, Sadayappan S, Ochala J, Gundersen K, Millay DP. Nuclear numbers in syncytial muscle fibers promote size but limit the development of larger myonuclear domains. Nat Commun 2020; 11:6287. [PMID: 33293533 PMCID: PMC7722938 DOI: 10.1038/s41467-020-20058-7] [Citation(s) in RCA: 47] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2019] [Accepted: 10/30/2020] [Indexed: 12/11/2022] Open
Abstract
Mammalian cells exhibit remarkable diversity in cell size, but the factors that regulate establishment and maintenance of these sizes remain poorly understood. This is especially true for skeletal muscle, comprised of syncytial myofibers that each accrue hundreds of nuclei during development. Here, we directly explore the assumed causal relationship between multinucleation and establishment of normal size through titration of myonuclear numbers during mouse neonatal development. Three independent mouse models, where myonuclear numbers were reduced by 75, 55, or 25%, led to the discovery that myonuclei possess a reserve capacity to support larger functional cytoplasmic volumes in developing myofibers. Surprisingly, the results revealed an inverse relationship between nuclei numbers and reserve capacity. We propose that as myonuclear numbers increase, the range of transcriptional return on a per nuclear basis in myofibers diminishes, which accounts for both the absolute reliance developing myofibers have on nuclear accrual to establish size, and the limits of adaptability in adult skeletal muscle.
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Affiliation(s)
- Alyssa A W Cramer
- Division of Molecular Cardiovascular Biology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, 45229, USA
| | - Vikram Prasad
- Division of Molecular Cardiovascular Biology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, 45229, USA
| | - Einar Eftestøl
- Division of Molecular Cardiovascular Biology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, 45229, USA
- Department of Biosciences, University of Oslo, Oslo, Norway
| | - Taejeong Song
- Department of Internal Medicine, Division of Cardiovascular Health and Disease, University of Cincinnati College of Medicine, Cincinnati, OH, 45229, USA
| | - Kenth-Arne Hansson
- Department of Biosciences, University of Oslo, Oslo, Norway
- Center for Integrative Neuroplasticity (CINPLA), Department of Biosciences, University of Oslo, Oslo, Norway
| | - Hannah F Dugdale
- Center of Human and Applied Physiological Sciences, School of Basic and Medical Biosciences, Faculty of Life Sciences & Medicine, King's College London, London, UK
| | - Sakthivel Sadayappan
- Department of Internal Medicine, Division of Cardiovascular Health and Disease, University of Cincinnati College of Medicine, Cincinnati, OH, 45229, USA
| | - Julien Ochala
- Center of Human and Applied Physiological Sciences, School of Basic and Medical Biosciences, Faculty of Life Sciences & Medicine, King's College London, London, UK
- Randall Center for Cell and Molecular Biophysics, School of Basic & Medical Biosciences, Faculty of Life Sciences & Medicine, Guy's Campus, King's College London, London, UK
- Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
| | | | - Douglas P Millay
- Division of Molecular Cardiovascular Biology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, 45229, USA.
- Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, OH, 45229, USA.
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10
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Chemoradiation impairs myofiber hypertrophic growth in a pediatric tumor model. Sci Rep 2020; 10:19501. [PMID: 33177579 PMCID: PMC7659015 DOI: 10.1038/s41598-020-75913-w] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2020] [Accepted: 10/19/2020] [Indexed: 01/05/2023] Open
Abstract
Pediatric cancer treatment often involves chemotherapy and radiation, where off-target effects can include skeletal muscle decline. The effect of such treatments on juvenile skeletal muscle growth has yet to be investigated. We employed a small animal irradiator to administer fractionated hindlimb irradiation to juvenile mice bearing implanted rhabdomyosarcoma (RMS) tumors. Hindlimb-targeted irradiation (3 × 8.2 Gy) of 4-week-old mice successfully eliminated RMS tumors implanted one week prior. After establishment of this preclinical model, a cohort of tumor-bearing mice were injected with the chemotherapeutic drug, vincristine, alone or in combination with fractionated irradiation (5 × 4.8 Gy). Single myofiber analysis of fast-contracting extensor digitorum longus (EDL) and slow-contracting soleus (SOL) muscles was conducted 3 weeks post-treatment. Although a reduction in myofiber size was apparent, EDL and SOL myonuclear number were differentially affected by juvenile irradiation and/or vincristine treatment. In contrast, a decrease in myonuclear domain (myofiber volume/myonucleus) was observed regardless of muscle or treatment. Thus, inhibition of myofiber hypertrophic growth is a consistent feature of pediatric cancer treatment.
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11
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Ross JA, Tasfaout H, Levy Y, Morgan J, Cowling BS, Laporte J, Zanoteli E, Romero NB, Lowe DA, Jungbluth H, Lawlor MW, Mack DL, Ochala J. rAAV-related therapy fully rescues myonuclear and myofilament function in X-linked myotubular myopathy. Acta Neuropathol Commun 2020; 8:167. [PMID: 33076971 PMCID: PMC7574461 DOI: 10.1186/s40478-020-01048-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2020] [Accepted: 10/02/2020] [Indexed: 01/17/2023] Open
Abstract
X-linked myotubular myopathy (XLMTM) is a life-threatening skeletal muscle disease caused by mutations in the MTM1 gene. XLMTM fibres display a population of nuclei mispositioned in the centre. In the present study, we aimed to explore whether positioning and overall distribution of nuclei affects cellular organization and contractile function, thereby contributing to muscle weakness in this disease. We also assessed whether gene therapy alters nuclear arrangement and function. We used tissue from human patients and animal models, including XLMTM dogs that had received increasing doses of recombinant AAV8 vector restoring MTM1 expression (rAAV8-cMTM1). We then used single isolated muscle fibres to analyze nuclear organization and contractile function. In addition to the expected mislocalization of nuclei in the centre of muscle fibres, a novel form of nuclear mispositioning was observed: irregular spacing between those located at the fibre periphery, and an overall increased number of nuclei, leading to dramatically smaller and inconsistent myonuclear domains. Nuclear mislocalization was associated with decreases in global nuclear synthetic activity, contractile protein content and intrinsic myofilament force production. A contractile deficit originating at the myofilaments, rather than mechanical interference by centrally positioned nuclei, was supported by experiments in regenerated mouse muscle. Systemic administration of rAAV8-cMTM1 at doses higher than 2.5 × 1013 vg kg−1 allowed a full rescue of all these cellular defects in XLMTM dogs. Altogether, these findings identify previously unrecognized pathological mechanisms in human and animal XLMTM, associated with myonuclear defects and contractile filament function. These defects can be reversed by gene therapy restoring MTM1 expression in dogs with XLMTM.
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12
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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: 39] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2019] [Revised: 12/09/2019] [Accepted: 12/12/2019] [Indexed: 12/12/2022]
Abstract
Prolonged unloading of skeletal muscle, a common outcome of events such as spaceflight, bed rest and hindlimb unloading, can result in extensive metabolic, structural and functional changes in muscle fibres. With advancement in investigations of cellular and molecular mechanisms, understanding of disuse muscle atrophy has significantly increased. However, substantial gaps exist in our understanding of the processes dictating muscle plasticity during unloading, which prevent us from developing effective interventions to combat muscle loss. This review aims to update the status of knowledge and underlying mechanisms leading to cellular and molecular changes in skeletal muscle during unloading. We have also discussed advances in the understanding of contractile dysfunction during spaceflights and in ground-based models of muscle unloading. Additionally, we have elaborated on potential therapeutic interventions that show promising results in boosting muscle mass and strength during mechanical unloading. Finally, we have identified key gaps in our knowledge as well as possible research direction for the future.
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Affiliation(s)
- Rizwan Qaisar
- Department of Basic Medical Sciences College of Medicine University of Sharjah Sharjah UAE
| | - Asima Karim
- Department of Basic Medical Sciences College of Medicine University of Sharjah Sharjah UAE
| | - Adel B. Elmoselhi
- Department of Basic Medical Sciences College of Medicine University of Sharjah Sharjah UAE
- Department of Physiology Michigan State University East Lansing MI USA
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13
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Abstract
The hallmark of most cardiac diseases is the progressive loss of cardiomyocytes. In the perinatal period, cardiomyocytes still proliferate, and the heart shows the capacity to regenerate upon injury. In the adult heart, however, the actual rate of cardiomyocyte renewal is too low to efficiently counteract substantial cell loss caused by cardiac injury. In mammals, cardiac growth by cell number expansion changes to growth by cardiomyocyte enlargement soon after birth, coinciding with a period in which most cardiomyocytes increase their DNA content by multinucleation and nuclear polyploidization. Although cardiomyocyte hypertrophy is often associated with these processes, whether polyploidy is a prerequisite or a consequence of hypertrophic growth is unclear. Both the benefits of cardiomyocyte enlargement over proliferative growth of the heart and the physiological role of polyploidy in cardiomyocytes are enigmatic. Interestingly, hearts in animal species with substantial cardiac regenerative capacity dominantly comprise diploid cardiomyocytes, raising the hypothesis that cardiomyocyte polyploidy poses a barrier for cardiomyocyte proliferation and subsequent heart regeneration. On the contrary, there is also evidence for self-duplication of multinucleated myocytes, suggesting a more complex picture of polyploidy in heart regeneration. Polyploidy is not restricted to the heart but also occurs in other cell types in the body. In this review, we explore the biological relevance of polyploidy in different species and tissues to acquire insight into its specific role in cardiomyocytes. Furthermore, we speculate about the physiological role of polyploidy in cardiomyocytes and how this might relate to renewal and regeneration.
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Affiliation(s)
- Wouter Derks
- From the Center for Regenerative Therapies Dresden, Technische Universität Dresden, Germany (W.D., O.B.)
| | - Olaf Bergmann
- From the Center for Regenerative Therapies Dresden, Technische Universität Dresden, Germany (W.D., O.B.).,Karolinska Institutet, Cell and Molecular Biology, Stockholm, Sweden (O.B.)
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14
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Beedour R, Ross JA, Levy Y, Ochala J. Effect of PGC1-beta ablation on myonuclear organisation. J Muscle Res Cell Motil 2019; 40:335-341. [PMID: 31485877 PMCID: PMC6831542 DOI: 10.1007/s10974-019-09549-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Skeletal muscle fibres are large, elongated multinucleated cells. Each nucleus within a myofibre is responsible for generating gene products for a finite volume of cytoplasm-the myonuclear domain (MND). Variation in MND sizes during atrophy, hypertrophy and disease states, are common. The factors that contribute to definitive MND sizes are not yet fully understood. Previous work has shown that peroxisome proliferator-activated receptor gamma coactivator 1α (PGC1-α) modulates MND volume, presumably to support increased biogenesis of mitochondria. The transcriptional co-regulator peroxisome proliferator-activated receptor gamma coactivator 1β (PGC1-β) is a homologue of PGC1-α with overlapping functions. To investigate the role of this protein in MND size regulation, we studied a mouse skeletal muscle specific knockout (cKO). Myofibres were isolated from the fast twitch extensor digitorum longus (EDL) muscle, membrane-permeabilised and analysed in 3 dimensions using confocal microscopy. PGC1-β ablation resulted in no significant difference in MND size between cKO and wild type (WT) mice, however, subtle differences in nuclear morphology were observed. To determine whether these nuclear shape changes were associated with alterations in global transcriptional activity, acetyl histone H3 immunostaining was carried out. We found there was no significant difference in nuclear fluorescence intensity between the two genotypes. Overall, the results suggest that PGC-1α and PGC-1β play different roles in regulating nuclear organisation in skeletal muscle; however, further work is required to pinpoint their exact functions.
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Affiliation(s)
- Ryan Beedour
- Faculty of Life Sciences & Medicine, School of Basic and Medical Biosciences, Centre of Human and Applied Physiological Sciences, King's College London, London, UK
| | - Jacob A Ross
- Faculty of Life Sciences & Medicine, School of Basic and Medical Biosciences, Centre of Human and Applied Physiological Sciences, King's College London, London, UK
| | - Yotam Levy
- Faculty of Life Sciences & Medicine, School of Basic and Medical Biosciences, Centre of Human and Applied Physiological Sciences, King's College London, London, UK
| | - Julien Ochala
- Faculty of Life Sciences & Medicine, School of Basic and Medical Biosciences, Centre of Human and Applied Physiological Sciences, King's College London, London, UK.
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15
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Ferreira DMS, Cheng AJ, Agudelo LZ, Cervenka I, Chaillou T, Correia JC, Porsmyr-Palmertz M, Izadi M, Hansson A, Martínez-Redondo V, Valente-Silva P, Pettersson-Klein AT, Estall JL, Robinson MM, Nair KS, Lanner JT, Ruas JL. LIM and cysteine-rich domains 1 (LMCD1) regulates skeletal muscle hypertrophy, calcium handling, and force. Skelet Muscle 2019; 9:26. [PMID: 31666122 PMCID: PMC6822430 DOI: 10.1186/s13395-019-0214-1] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2019] [Accepted: 09/30/2019] [Indexed: 12/27/2022] Open
Abstract
BACKGROUND Skeletal muscle mass and strength are crucial determinants of health. Muscle mass loss is associated with weakness, fatigue, and insulin resistance. In fact, it is predicted that controlling muscle atrophy can reduce morbidity and mortality associated with diseases such as cancer cachexia and sarcopenia. METHODS We analyzed gene expression data from muscle of mice or human patients with diverse muscle pathologies and identified LMCD1 as a gene strongly associated with skeletal muscle function. We transiently expressed or silenced LMCD1 in mouse gastrocnemius muscle or in mouse primary muscle cells and determined muscle/cell size, targeted gene expression, kinase activity with kinase arrays, protein immunoblotting, and protein synthesis levels. To evaluate force, calcium handling, and fatigue, we transduced the flexor digitorum brevis muscle with a LMCD1-expressing adenovirus and measured specific force and sarcoplasmic reticulum Ca2+ release in individual fibers. Finally, to explore the relationship between LMCD1 and calcineurin, we ectopically expressed Lmcd1 in the gastrocnemius muscle and treated those mice with cyclosporine A (calcineurin inhibitor). In addition, we used a luciferase reporter construct containing the myoregulin gene promoter to confirm the role of a LMCD1-calcineurin-myoregulin axis in skeletal muscle mass control and calcium handling. RESULTS Here, we identify LIM and cysteine-rich domains 1 (LMCD1) as a positive regulator of muscle mass, that increases muscle protein synthesis and fiber size. LMCD1 expression in vivo was sufficient to increase specific force with lower requirement for calcium handling and to reduce muscle fatigue. Conversely, silencing LMCD1 expression impairs calcium handling and force, and induces muscle fatigue without overt atrophy. The actions of LMCD1 were dependent on calcineurin, as its inhibition using cyclosporine A reverted the observed hypertrophic phenotype. Finally, we determined that LMCD1 represses the expression of myoregulin, a known negative regulator of muscle performance. Interestingly, we observed that skeletal muscle LMCD1 expression is reduced in patients with skeletal muscle disease. CONCLUSIONS Our gain- and loss-of-function studies show that LMCD1 controls protein synthesis, muscle fiber size, specific force, Ca2+ handling, and fatigue resistance. This work uncovers a novel role for LMCD1 in the regulation of skeletal muscle mass and function with potential therapeutic implications.
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Affiliation(s)
- Duarte M S Ferreira
- Molecular & Cellular Exercise Physiology, Department of Physiology and Pharmacology, Karolinska Institutet, Biomedicum, SE-171 77, Stockholm, Sweden
| | - Arthur J Cheng
- Molecular Muscle Physiology and Pathophysiology, Department of Physiology and Pharmacology, Karolinska Institutet, Biomedicum, SE-171 77, Stockholm, Sweden.,Present Address: Faculty of Health, York University, School of Kinesiology and Health Science, Toronto, Ontario, Canada
| | - Leandro Z Agudelo
- Molecular & Cellular Exercise Physiology, Department of Physiology and Pharmacology, Karolinska Institutet, Biomedicum, SE-171 77, Stockholm, Sweden.,Present Address: Computer Science and Artificial Intelligence Laboratory, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
| | - Igor Cervenka
- Molecular & Cellular Exercise Physiology, Department of Physiology and Pharmacology, Karolinska Institutet, Biomedicum, SE-171 77, Stockholm, Sweden
| | - Thomas Chaillou
- Molecular Muscle Physiology and Pathophysiology, Department of Physiology and Pharmacology, Karolinska Institutet, Biomedicum, SE-171 77, Stockholm, Sweden.,School of Health Sciences, Örebro University, Örebro, Sweden
| | - Jorge C Correia
- Molecular & Cellular Exercise Physiology, Department of Physiology and Pharmacology, Karolinska Institutet, Biomedicum, SE-171 77, Stockholm, Sweden
| | - Margareta Porsmyr-Palmertz
- Molecular & Cellular Exercise Physiology, Department of Physiology and Pharmacology, Karolinska Institutet, Biomedicum, SE-171 77, Stockholm, Sweden
| | - Manizheh Izadi
- Molecular & Cellular Exercise Physiology, Department of Physiology and Pharmacology, Karolinska Institutet, Biomedicum, SE-171 77, Stockholm, Sweden.,Present Address: Karp Research Building, Boston, MA, 02115, USA
| | - Alicia Hansson
- Molecular & Cellular Exercise Physiology, Department of Physiology and Pharmacology, Karolinska Institutet, Biomedicum, SE-171 77, Stockholm, Sweden
| | - Vicente Martínez-Redondo
- Molecular & Cellular Exercise Physiology, Department of Physiology and Pharmacology, Karolinska Institutet, Biomedicum, SE-171 77, Stockholm, Sweden
| | - Paula Valente-Silva
- Molecular & Cellular Exercise Physiology, Department of Physiology and Pharmacology, Karolinska Institutet, Biomedicum, SE-171 77, Stockholm, Sweden
| | - Amanda T Pettersson-Klein
- Molecular & Cellular Exercise Physiology, Department of Physiology and Pharmacology, Karolinska Institutet, Biomedicum, SE-171 77, Stockholm, Sweden
| | - Jennifer L Estall
- Division of Cardiovascular and Metabolic Disease, Institut de recherches cliniques de Montreal (IRCM), Montreal, QC, Canada
| | - Matthew M Robinson
- Division of Endocrinology, Diabetes and Nutrition, Mayo Clinic, Rochester, MN, 55905, USA
| | - K Sreekumaran Nair
- Division of Endocrinology, Diabetes and Nutrition, Mayo Clinic, Rochester, MN, 55905, USA
| | - Johanna T Lanner
- Molecular Muscle Physiology and Pathophysiology, Department of Physiology and Pharmacology, Karolinska Institutet, Biomedicum, SE-171 77, Stockholm, Sweden
| | - Jorge L Ruas
- Molecular & Cellular Exercise Physiology, Department of Physiology and Pharmacology, Karolinska Institutet, Biomedicum, SE-171 77, Stockholm, Sweden.
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16
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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: 756] [Impact Index Per Article: 151.2] [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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17
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Fokin A, Minderis P, Venckunas T, Lionikas A, Kvedaras M, Ratkevicius A. Myostatin dysfunction does not protect from fasting-induced loss of muscle mass in mice. JOURNAL OF MUSCULOSKELETAL & NEURONAL INTERACTIONS 2019; 19:342-353. [PMID: 31475942 PMCID: PMC6737554] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
OBJECTIVES The aim of the study was to investigate if myostatin dysfunction can ameliorate fasting-induced muscle wasting. METHODS 18-week old males from Berlin high (BEH) strain with myostatin dysfunction and wild type myostatin (BEH+/+) strain were subjected to 48-h food deprivation (FD). Changes in body composition as well as contractile properties of soleus (SOL) and extensor digitorum longus (EDL) muscles were studied. RESULTS BEH mice were heavier than BEH+/+ mice (56.0±2.5 vs. 49.9±2.8 g, P<0.001, respectively). FD induced similar loss of body mass in BEH and BEH+/+ mice (16.6±2.4 vs. 17.4±2.2%, P>0.05), but only BEH mice experienced wasting of the gastrocnemius, tibialis anterior and plantaris muscles. FD induced a marked decrease in specific muscle force of SOL. EDL of BEH mice tended to be protected from this decline. CONCLUSION Myostatin dysfunction does not protect from loss of muscle mass during fasting.
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Affiliation(s)
- Andrej Fokin
- Institute of Sport Science and Innovations, Lithuanian Sports University, Kaunas, Lithuania
| | - Petras Minderis
- Institute of Sport Science and Innovations, Lithuanian Sports University, Kaunas, Lithuania
| | - Tomas Venckunas
- Institute of Sport Science and Innovations, Lithuanian Sports University, Kaunas, Lithuania,Department of Applied Biology and Rehabilitation, Lithuanian Sports University, Kaunas, Lithuania
| | - Arimantas Lionikas
- School of Medicine, Medical Sciences and Nutrition, College of Life Sciences and Medicine, University of Aberdeen, Aberdeen, Scotland, UK
| | - Mindaugas Kvedaras
- Institute of Sport Science and Innovations, Lithuanian Sports University, Kaunas, Lithuania
| | - Aivaras Ratkevicius
- Department of Applied Biology and Rehabilitation, Lithuanian Sports University, Kaunas, Lithuania,Corresponding author: Dr. Aivaras Ratkevicius, Department of Applied Biology and Rehabilitation, Lithuanian Sports University, Sporto g. 6, LT-44221 Kaunas, Lithuania E-mail:
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18
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Levy Y, Ross JA, Niglas M, Snetkov VA, Lynham S, Liao CY, Puckelwartz MJ, Hsu YM, McNally EM, Alsheimer M, Harridge SD, Young SG, Fong LG, Español Y, Lopez-Otin C, Kennedy BK, Lowe DA, Ochala J. Prelamin A causes aberrant myonuclear arrangement and results in muscle fiber weakness. JCI Insight 2018; 3:120920. [PMID: 30282816 PMCID: PMC6237469 DOI: 10.1172/jci.insight.120920] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2018] [Accepted: 08/23/2018] [Indexed: 01/06/2023] Open
Abstract
Physiological and premature aging are frequently associated with an accumulation of prelamin A, a precursor of lamin A, in the nuclear envelope of various cell types. Here, we aimed to underpin the hitherto unknown mechanisms by which prelamin A alters myonuclear organization and muscle fiber function. By experimentally studying membrane-permeabilized myofibers from various transgenic mouse lines, our results indicate that, in the presence of prelamin A, the abundance of nuclei and myosin content is markedly reduced within muscle fibers. This leads to a concept by which the remaining myonuclei are very distant from each other and are pushed to function beyond their maximum cytoplasmic capacity, ultimately inducing muscle fiber weakness.
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Affiliation(s)
- Yotam Levy
- School of Basic and Medical Biosciences, Faculty of Life Sciences & Medicine, and
| | - Jacob A Ross
- School of Basic and Medical Biosciences, Faculty of Life Sciences & Medicine, and
| | - Marili Niglas
- School of Basic and Medical Biosciences, Faculty of Life Sciences & Medicine, and
| | - Vladimir A Snetkov
- School of Basic and Medical Biosciences, Faculty of Life Sciences & Medicine, and
| | - Steven Lynham
- Proteomics Facility, Centre of Excellence for Mass Spectrometry, King's College London, London, United Kingdom
| | - Chen-Yu Liao
- Buck Institute for Research on Aging, Novato, California, USA
| | - Megan J Puckelwartz
- Center for Genetic Medicine, Northwestern University, Chicago, Illinois, USA
| | - Yueh-Mei Hsu
- Buck Institute for Research on Aging, Novato, California, USA
| | - Elizabeth M McNally
- Center for Genetic Medicine, Northwestern University, Chicago, Illinois, USA
| | - Manfred Alsheimer
- Department of Cell and Developmental Biology, University of Würzburg, Würzburg, Germany
| | - Stephen Dr Harridge
- School of Basic and Medical Biosciences, Faculty of Life Sciences & Medicine, and
| | - Stephen G Young
- Department of Medicine, University of California Los Angeles, Los Angeles, California, USA
| | - Loren G Fong
- Department of Medicine, University of California Los Angeles, Los Angeles, California, USA
| | - Yaiza Español
- Departamento de Bioquímica y Biología Molecular, Facultad de Medicina, Instituto Universitario de Oncología (IUOPA), Universidad de Oviedo, Oviedo, Spain
| | - Carlos Lopez-Otin
- Departamento de Bioquímica y Biología Molecular, Facultad de Medicina, Instituto Universitario de Oncología (IUOPA), Universidad de Oviedo, Oviedo, Spain.,Centro de Investigación Biomédica en Red de Cáncer (CIBERONC), Spain
| | - Brian K Kennedy
- Buck Institute for Research on Aging, Novato, California, USA.,Departments of Biochemistry and Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore.,Centre for Healthy Ageing, National University Health System, Singapore.,Singapore Institute for Clinical Sciences, Singapore
| | - Dawn A Lowe
- Divisions of Rehabilitation Science and Physical Therapy, Department of Rehabilitation Medicine, School of Medicine, University of Minnesota, Minneapolis, Minnesota, USA
| | - Julien Ochala
- School of Basic and Medical Biosciences, Faculty of Life Sciences & Medicine, and
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19
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Satkunskiene D, Ratkevicius A, Kamandulis S, Venckunas T. Effects of myostatin on the mechanical properties of muscles during repeated active lengthening in the mouse. Appl Physiol Nutr Metab 2018; 44:381-388. [PMID: 30222937 DOI: 10.1139/apnm-2018-0369] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The aim of the present study was to investigate how myostatin dysfunction affects fast and slow muscle stiffness and viscosity during severe repeated loading. Isolated extensor digitorum longus (EDL) and soleus muscles of young adult female mice of the BEH (dysfunctional myostatin) and BEH+/+ (functional myostatin) strains were subjected to 100 contraction-stretching loading cycles during which contractile and mechanical properties were assessed. BEH mice exhibited greater exercise-induced muscle damage, although the effect was muscle- and age-dependent and limited to the early phases of simulated exercise. The relative reduction of the EDL muscle isometric force recorded during the initial 10-30 loading cycles was greater in BEH mice than in BEH+/+ mice and exceeded that of the soleus muscle of either strain. The induced damage was associated with lower muscle stiffness. The effects of myostatin on the mechanical properties of muscles depend on muscle type and maturity.
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Affiliation(s)
- Danguole Satkunskiene
- Institute of Sports Science and Innovation, Lithuanian Sports University, Kaunas, Lithuania.,Institute of Sports Science and Innovation, Lithuanian Sports University, Kaunas, Lithuania
| | - Aivaras Ratkevicius
- Institute of Sports Science and Innovation, Lithuanian Sports University, Kaunas, Lithuania.,Institute of Sports Science and Innovation, Lithuanian Sports University, Kaunas, Lithuania
| | - Sigitas Kamandulis
- Institute of Sports Science and Innovation, Lithuanian Sports University, Kaunas, Lithuania.,Institute of Sports Science and Innovation, Lithuanian Sports University, Kaunas, Lithuania
| | - Tomas Venckunas
- Institute of Sports Science and Innovation, Lithuanian Sports University, Kaunas, Lithuania.,Institute of Sports Science and Innovation, Lithuanian Sports University, Kaunas, Lithuania
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20
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Ross JA, Levy Y, Svensson K, Philp A, Schenk S, Ochala J. SIRT1 regulates nuclear number and domain size in skeletal muscle fibers. J Cell Physiol 2018; 233:7157-7163. [PMID: 29574748 PMCID: PMC5993587 DOI: 10.1002/jcp.26542] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2017] [Accepted: 02/12/2018] [Indexed: 12/16/2022]
Abstract
Skeletal muscle fibers are giant multinucleated cells wherein individual nuclei govern the protein synthesis in a finite volume of cytoplasm; this is termed the myonuclear domain (MND). The factors that control MND size remain to be defined. In the present study, we studied the contribution of the NAD+‐dependent deacetylase, sirtuin 1 (SIRT1), to the regulation of nuclear number and MND size. For this, we isolated myofibers from mice with tissue‐specific inactivation (mKO) or inducible overexpression (imOX) of SIRT1 and analyzed the 3D organisation of myonuclei. In imOX mice, the number of nuclei was increased whilst the average MND size was decreased as compared to littermate controls. Our findings were the opposite in mKO mice. Muscle stem cell (satellite cell) numbers were reduced in mKO muscles, a possible explanation for the lower density of myonuclei in these mice; however, no change was observed in imOX mice, suggesting that other factors might also be involved, such as the functional regulation of stem cells/muscle precursors. Interestingly, however, the changes in the MND volume did not impact the force‐generating capacity of muscle fibers. Taken together, our results demonstrate that SIRT1 is a key regulator of MND sizes, although the underlying molecular mechanisms and the cause‐effect relationship between MND and muscle function remain to be fully defined.
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Affiliation(s)
- Jacob A Ross
- School of Basic and Medical Biosciences, Faculty of Life Sciences and Medicine, King's College London, London, UK
| | - Yotam Levy
- School of Basic and Medical Biosciences, Faculty of Life Sciences and Medicine, King's College London, London, UK
| | - Kristoffer Svensson
- Department of Orthopaedic Surgery, University of California San Diego, La Jolla, California.,Biomedical Sciences Graduate Program, University of California San Diego, La Jolla, California
| | - Andrew Philp
- School of Sport and Exercise Sciences, University of Birmingham, Birmingham, UK
| | - Simon Schenk
- Department of Orthopaedic Surgery, University of California San Diego, La Jolla, California.,Biomedical Sciences Graduate Program, University of California San Diego, La Jolla, California
| | - Julien Ochala
- School of Basic and Medical Biosciences, Faculty of Life Sciences and Medicine, King's College London, London, UK
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21
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Klose A, Liu W, Paris ND, Forman S, Krolewski JJ, Nastiuk KL, Chakkalakal JV. Castration induces satellite cell activation that contributes to skeletal muscle maintenance. JCSM RAPID COMMUNICATIONS 2018; 1:e00040. [PMID: 29782610 PMCID: PMC5959044] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
BACKGROUND Sarcopenia, the age-related loss of skeletal muscle, is a side effect of androgen deprivation therapy (ADT) for prostate cancer patients. Resident stem cells of skeletal muscle, satellite cells (SCs), are an essential source of progenitors for the growth and regeneration of skeletal muscle. Decreased androgen signaling and deficits in the number and function of SCs are features of aging. Although androgen signaling is known to regulate skeletal muscle, the cellular basis for ADT-induced exacerbation of sarcopenia is unknown. Furthermore, the consequences of androgen deprivation on SC fate in adult skeletal muscle remain largely unexplored. METHODS We examined SC fate in an androgen-deprived environment using immunofluorescence and fluorescence-activated cell sorting (FACS) with SC-specific markers in young castrated mice. To study the effects of androgen deprivation on SC function and skeletal muscle regenerative capacity, young castrated mice were subjected to experimental regenerative paradigms. SC-derived-cell contributions to skeletal muscle maintenance were examined in castrated Pax7CreER/+; ROSA26mTmG/+ mice. SCs were depleted in Pax7CreER/+; ROSA26DTA/+ mice to ascertain the consequences of SC ablation in sham and castrated skeletal muscles. Confocal immunofluorescence analysis of neuromuscular junctions (NMJs), and assessment of skeletal muscle physiology, contractile properties, and integrity were conducted. RESULTS Castration led to SC activation, however this did not result in a decline in SC function or skeletal muscle regenerative capacity. Surprisingly, castration induced SC-dependent maintenance of young skeletal muscle. The functional dependence of skeletal muscles on SCs in young castrated mice was demonstrated by an increase in SC-derived-cell fusion within skeletal muscle fibers. SC depletion was associated with further atrophy and functional decline, as well as the induction of partial innervation and the loss of NMJ-associated myonuclei in skeletal muscles from castrated mice. CONCLUSION The maintenance of skeletal muscles in young castrated mice relies on the cellular contributions of SCs. Considering the well-described age-related decline in SCs, the results in this study highlight the need to devise strategies that promote SC maintenance and activity to attenuate or reverse the progression of sarcopenia in elderly androgen-deprived individuals.
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Affiliation(s)
- Alanna Klose
- Department of Orthopaedics and Rehabilitation, Center for Musculoskeletal Research, University of Rochester Medical Center, Rochester, NY USA
| | - Wenxuan Liu
- Department of Orthopaedics and Rehabilitation, Center for Musculoskeletal Research, University of Rochester Medical Center, Rochester, NY USA
| | - Nicole D. Paris
- Department of Orthopaedics and Rehabilitation, Center for Musculoskeletal Research, University of Rochester Medical Center, Rochester, NY USA
| | - Sophie Forman
- Department of Orthopaedics and Rehabilitation, Center for Musculoskeletal Research, University of Rochester Medical Center, Rochester, NY USA
| | - John J. Krolewski
- Department of Cancer Genetics & Genomics, and Center for Personalized Medicine, Roswell Park Cancer Institute; Buffalo, NY USA
| | - Kent L. Nastiuk
- Department of Cancer Genetics & Genomics, and Department of Urology, Roswell Park Cancer Institute; Buffalo, NY USA
| | - Joe V. Chakkalakal
- Department of Orthopaedics and Rehabilitation, Center for Musculoskeletal Research, University of Rochester Medical Center, Rochester, NY USA
- Stem Cell and Regenerative Medicine Institute, University of Rochester Medical Center, Rochester, NY USA
- The Rochester Aging Research Center, University of Rochester Medical Center, Rochester, NY USA
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22
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Ueberschlag-Pitiot V, Stantzou A, Messéant J, Lemaitre M, Owens DJ, Noirez P, Roy P, Agbulut O, Metzger D, Ferry A. Gonad-related factors promote muscle performance gain during postnatal development in male and female mice. Am J Physiol Endocrinol Metab 2017; 313:E12-E25. [PMID: 28351832 DOI: 10.1152/ajpendo.00446.2016] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/13/2016] [Revised: 02/22/2017] [Accepted: 03/22/2017] [Indexed: 11/22/2022]
Abstract
To better define the role of male and female gonad-related factors (MGRF, presumably testosterone, and FGRF, presumably estradiol, respectively) on mouse hindlimb skeletal muscle contractile performance/function gain during postnatal development, we analyzed the effect of castration initiated before puberty in male and female mice. We found that muscle absolute and specific (normalized to muscle weight) maximal forces were decreased in 6-mo-old male and female castrated mice compared with age- and sex-matched intact mice, without alteration in neuromuscular transmission. Moreover, castration decreased absolute and specific maximal powers, another important aspect of muscle performance, in 6-mo-old males, but not in females. Absolute maximal force was similarly reduced by castration in 3-mo-old muscle fiber androgen receptor (AR)-deficient and wild-type male mice, indicating that the effect of MGRF was muscle fiber AR independent. Castration reduced the muscle weight gain in 3-mo mice of both sexes and in 6-mo females but not in males. We also found that bone morphogenetic protein signaling through Smad1/5/9 was not altered by castration in atrophic muscle of 3-mo-old mice of both sexes. Moreover, castration decreased the sexual dimorphism regarding muscle performance. Together, these results demonstrated that in the long term, MGRF and FGRF promote muscle performance gain in mice during postnatal development, independently of muscle growth in males, largely via improving muscle contractile quality (force and power normalized), and that MGFR and FGRF also contribute to sexual dimorphism. However, the mechanisms underlying MGFR and FGRF actions remain to be determined.
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Affiliation(s)
- Vanessa Ueberschlag-Pitiot
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, Université de Strasbourg, CNRS UMR7104/INSERM U964, Illkirch, France
| | - Amalia Stantzou
- Sorbonne Universités, Université Pierre et Marie Curie-Paris6, Myology Research Center, UM76 and INSERM U974 and CNRS FRE 3617 and Institut de Myologie, Paris, France
| | - Julien Messéant
- Sorbonne Universités, Université Pierre et Marie Curie-Paris6, Myology Research Center, UM76 and INSERM U974 and CNRS FRE 3617 and Institut de Myologie, Paris, France
| | - Megane Lemaitre
- Sorbonne Universités, Université Pierre et Marie Curie-Paris6, Myology Research Center, UM76 and INSERM U974 and CNRS FRE 3617 and Institut de Myologie, Paris, France
| | - Daniel J Owens
- Sorbonne Universités, Université Pierre et Marie Curie-Paris6, Myology Research Center, UM76 and INSERM U974 and CNRS FRE 3617 and Institut de Myologie, Paris, France
| | - Philippe Noirez
- Institut de Recherche Biomédicale et D'épidemiologie du Sport, EA 7329, Institut National du Sport de l'Expertise et de la Performance, Laboratory of Excellence GR-Ex, Paris, France
- Université Sorbonne Paris Cité, Université Paris Descartes, Paris, France; and
| | - Pauline Roy
- Sorbonne Universités, Université Pierre et Marie Curie-Paris6, Myology Research Center, UM76 and INSERM U974 and CNRS FRE 3617 and Institut de Myologie, Paris, France
| | - Onnik Agbulut
- Sorbonne Universités, Université Pierre et Marie Curie-Paris6, Institut de Biologie Paris-Seine, UMR CNRS 8256, Biological Adaptation and Ageing, Paris, France
| | - Daniel Metzger
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, Université de Strasbourg, CNRS UMR7104/INSERM U964, Illkirch, France
| | - Arnaud Ferry
- Sorbonne Universités, Université Pierre et Marie Curie-Paris6, Myology Research Center, UM76 and INSERM U974 and CNRS FRE 3617 and Institut de Myologie, Paris, France;
- Université Sorbonne Paris Cité, Université Paris Descartes, Paris, France; and
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23
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Terena SML, Fernandes KPS, Bussadori SK, Deana AM, Mesquita-Ferrari RA. Systematic review of the synergist muscle ablation model for compensatory hypertrophy. Rev Assoc Med Bras (1992) 2017; 63:164-172. [DOI: 10.1590/1806-9282.63.02.164] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2016] [Accepted: 06/26/2016] [Indexed: 11/21/2022] Open
Abstract
Summary Objective: The aim was to evaluate the effectiveness of the experimental synergists muscle ablation model to promote muscle hypertrophy, determine the period of greatest hypertrophy and its influence on muscle fiber types and determine differences in bilateral and unilateral removal to reduce the number of animals used in this model. Method: Following the application of the eligibility criteria for the mechanical overload of the plantar muscle in rats, nineteen papers were included in the review. Results: The results reveal a greatest hypertrophy occurring between days 12 and 15, and based on the findings, synergist muscle ablation is an efficient model for achieving rapid hypertrophy and the contralateral limb can be used as there was no difference between unilateral and bilateral surgery, which reduces the number of animals used in this model. Conclusion: This model differs from other overload models (exercise and training) regarding the characteristics involved in the hypertrophy process (acute) and result in a chronic muscle adaptation with selective regulation and modification of fast-twitch fibers in skeletal muscle. This is an efficient and rapid model for compensatory hypertrophy.
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24
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Ross JA, Pearson A, Levy Y, Cardel B, Handschin C, Ochala J. Exploring the Role of PGC-1α in Defining Nuclear Organisation in Skeletal Muscle Fibres. J Cell Physiol 2016; 232:1270-1274. [PMID: 27861863 DOI: 10.1002/jcp.25678] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2016] [Accepted: 11/03/2016] [Indexed: 12/16/2022]
Abstract
Muscle fibres are multinucleated cells, with each nucleus controlling the protein synthesis in a finite volume of cytoplasm termed the myonuclear domain (MND). What determines MND size remains unclear. In the present study, we aimed to test the hypothesis that the level of expression of the transcriptional coactivator PGC-1α and subsequent activation of the mitochondrial biogenesis are major contributors. Hence, we used two transgenic mouse models with varying expression of PGC-1α in skeletal muscles. We isolated myofibres from the fast twitch extensor digitorum longus (EDL) and slow twitch diaphragm muscles. We then membrane-permeabilised them and analysed the 3D spatial arrangements of myonuclei. In EDL muscles, when PGC-1α is over-expressed, MND volume decreases; whereas, when PGC-1α is lacking, no change occurs. In the diaphragm, no clear difference was noted. This indicates that PGC-1α and the related mitochondrial biogenesis programme are determinants of MND size. PGC-1α may facilitate the addition of new myonuclei in order to reach MND volumes that can support an increased mitochondrial density. J. Cell. Physiol. 232: 1270-1274, 2017. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- Jacob A Ross
- Centre of Human and Aerospace Physiological Sciences, Faculty of Life Sciences & Medicine, King's College London, London, UK
| | - Adam Pearson
- Centre of Human and Aerospace Physiological Sciences, Faculty of Life Sciences & Medicine, King's College London, London, UK
| | - Yotam Levy
- Centre of Human and Aerospace Physiological Sciences, Faculty of Life Sciences & Medicine, King's College London, London, UK
| | | | | | - Julien Ochala
- Centre of Human and Aerospace Physiological Sciences, Faculty of Life Sciences & Medicine, King's College London, London, UK
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25
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Activin Receptor Type IIB Inhibition Improves Muscle Phenotype and Function in a Mouse Model of Spinal Muscular Atrophy. PLoS One 2016; 11:e0166803. [PMID: 27870893 PMCID: PMC5117715 DOI: 10.1371/journal.pone.0166803] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2016] [Accepted: 11/03/2016] [Indexed: 12/18/2022] Open
Abstract
Spinal muscular atrophy (SMA) is a devastating neurodegenerative disorder that causes progressive muscle atrophy and weakness. Using adeno-associated virus-mediated gene transfer, we evaluated the potential to improve skeletal muscle weakness via systemic, postnatal inhibition of either myostatin or all signaling via the activin receptor type IIB (ActRIIB). After demonstrating elevated p-SMAD3 content and differential content of ActRIIB ligands, 4-week-old male C/C SMA model mice were treated intraperitoneally with 1x1012 genome copies of pseudotype 2/8 virus encoding a soluble form of the ActRIIB extracellular domain (sActRIIB) or protease-resistant myostatin propeptide (dnMstn) driven by a liver specific promoter. At 12 weeks of age, muscle mass and function were improved in treated C/C mice by both treatments, compared to controls. The fast fiber type muscles had a greater response to treatment than did slow muscles, and the greatest therapeutic effects were found with sActRIIB treatment. Myostatin/activin inhibition, however, did not rescue C/C mice from the reduction in motor unit numbers of the tibialis anterior muscle. Collectively, this study indicates that myostatin/activin inhibition represents a potential therapeutic strategy to increase muscle mass and strength, but not neuromuscular junction defects, in less severe forms of SMA.
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26
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Stantzou A, Ueberschlag-Pitiot V, Thomasson R, Furling D, Bonnieu A, Amthor H, Ferry A. Effect of constitutive inactivation of the myostatin gene on the gain in muscle strength during postnatal growth in two murine models. Muscle Nerve 2016; 55:254-261. [PMID: 27312354 DOI: 10.1002/mus.25220] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2015] [Revised: 04/20/2016] [Accepted: 06/13/2016] [Indexed: 11/07/2022]
Abstract
INTRODUCTION The effect of constitutive inactivation of the gene encoding myostatin on the gain in muscle performance during postnatal growth has not been well characterized. METHODS We analyzed 2 murine myostatin knockout (KO) models, (i) the Lee model (KOLee ) and (ii) the Grobet model (KOGrobet ), and measured the contraction of tibialis anterior muscle in situ. RESULTS Absolute maximal isometric force was increased in 6-month-old KOLee and KOGrobet mice, as compared to wild-type mice. Similarly, absolute maximal power was increased in 6-month-old KOLee mice. In contrast, specific maximal force (relative maximal force per unit of muscle mass was decreased in all 6-month-old male and female KO mice, except in 6-month-old female KOGrobet mice, whereas specific maximal power was reduced only in male KOLee mice. CONCLUSIONS Genetic inactivation of myostatin increases maximal force and power, but in return it reduces muscle quality, particularly in male mice. Muscle Nerve 55: 254-261, 2017.
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Affiliation(s)
- Amalia Stantzou
- Université de Versailles Saint-Quentin, Unité de formation et de recherche des sciences de la santé des sciences, Montigny-le-Bretonneux, France
| | - Vanessa Ueberschlag-Pitiot
- Université de Strasbourg, Institut de Génétique et de Biologie Moléculaire et Cellulaire, Illkirch, France
| | - Remi Thomasson
- Université Paris Descartes, Institut de Recherche bio-Médicale et d'Epidémiologie du Sport, Sorbonne Paris Cité, Paris, France
| | - Denis Furling
- Sorbonne Universités CNRS, Centre de Recherche en Myologie, Paris, France
| | - Anne Bonnieu
- INRA, Université Montpellier, Dynamique Musculaire et Métabolisme, Montpellier, France
| | - Helge Amthor
- Université de Versailles Saint-Quentin, Unité de formation et de recherche des sciences de la santé des sciences, Montigny-le-Bretonneux, France
| | - Arnaud Ferry
- Sorbonne Universités CNRS, Centre de Recherche en Myologie, Paris, France
- Université Paris Descartes, Sorbonne Paris Cité, Paris, France
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27
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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: 125] [Impact Index Per Article: 15.6] [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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28
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Kornegay JN, Bogan DJ, Bogan JR, Dow JL, Wang J, Fan Z, Liu N, Warsing LC, Grange RW, Ahn M, Balog-Alvarez CJ, Cotten SW, Willis MS, Brinkmeyer-Langford C, Zhu H, Palandra J, Morris CA, Styner MA, Wagner KR. Dystrophin-deficient dogs with reduced myostatin have unequal muscle growth and greater joint contractures. Skelet Muscle 2016; 6:14. [PMID: 27047655 PMCID: PMC4819282 DOI: 10.1186/s13395-016-0085-7] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2016] [Accepted: 02/24/2016] [Indexed: 09/02/2023] Open
Abstract
Background Myostatin (Mstn) is a negative regulator of muscle growth whose inhibition promotes muscle growth and regeneration. Dystrophin-deficient mdx mice in which myostatin is knocked out or inhibited postnatally have a less severe phenotype with greater total mass and strength and less fibrosis and fatty replacement of muscles than mdx mice with wild-type myostatin expression. Dogs with golden retriever muscular dystrophy (GRMD) have previously been noted to have increased muscle mass and reduced fibrosis after systemic postnatal myostatin inhibition. Based partly on these results, myostatin inhibitors are in development for use in human muscular dystrophies. However, persisting concerns regarding the effects of long-term and profound myostatin inhibition will not be easily or imminently answered in clinical trials. Methods To address these concerns, we developed a canine (GRippet) model by crossbreeding dystrophin-deficient GRMD dogs with Mstn-heterozygous (Mstn+/−) whippets. A total of four GRippets (dystrophic and Mstn+/−), three GRMD (dystrophic and Mstn wild-type) dogs, and three non-dystrophic controls from two litters were evaluated. Results Myostatin messenger ribonucleic acid (mRNA) and protein levels were downregulated in both GRMD and GRippet dogs. GRippets had more severe postural changes and larger (more restricted) maximal joint flexion angles, apparently due to further exaggeration of disproportionate effects on muscle size. Flexors such as the cranial sartorius were more hypertrophied on magnetic resonance imaging (MRI) in the GRippets, while extensors, including the quadriceps femoris, underwent greater atrophy. Myostatin protein levels negatively correlated with relative cranial sartorius muscle cross-sectional area on MRI, supporting a role in disproportionate muscle size. Activin receptor type IIB (ActRIIB) expression was higher in dystrophic versus control dogs, consistent with physiologic feedback between myostatin and ActRIIB. However, there was no differential expression between GRMD and GRippet dogs. Satellite cell exhaustion was not observed in GRippets up to 3 years of age. Conclusions Partial myostatin loss may exaggerate selective muscle hypertrophy or atrophy/hypoplasia in GRMD dogs and worsen contractures. While muscle imbalance is not a feature of myostatin inhibition in mdx mice, findings in a larger animal model could translate to human experience with myostatin inhibitors. Electronic supplementary material The online version of this article (doi:10.1186/s13395-016-0085-7) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Joe N Kornegay
- Department of Pathology and Laboratory Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599 USA ; Department of Neurology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599 USA ; Department of Veterinary Integrative Biosciences, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, TX 77843-4458 USA
| | - Daniel J Bogan
- Department of Pathology and Laboratory Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599 USA
| | - Janet R Bogan
- Department of Pathology and Laboratory Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599 USA
| | - Jennifer L Dow
- Department of Pathology and Laboratory Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599 USA
| | - Jiahui Wang
- Department of Psychiatry, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599 USA
| | - Zheng Fan
- Department of Neurology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599 USA
| | - Naili Liu
- The Hugo W. Moser Research Institute at Kennedy Krieger Institute and Departments of Neurology and Neuroscience, Johns Hopkins School of Medicine, Baltimore, MD 21205 USA
| | - Leigh C Warsing
- The Hugo W. Moser Research Institute at Kennedy Krieger Institute and Departments of Neurology and Neuroscience, Johns Hopkins School of Medicine, Baltimore, MD 21205 USA
| | - Robert W Grange
- Department of Human Nutrition, Foods and Exercise, Virginia Tech University, Blacksburg, VA 24061 USA
| | - Mihye Ahn
- Department of Biostatistics, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599 USA
| | - Cynthia J Balog-Alvarez
- Department of Veterinary Integrative Biosciences, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, TX 77843-4458 USA
| | - Steven W Cotten
- Department of Pathology, The Ohio State University, Columbus, OH 43210 USA
| | - Monte S Willis
- Department of Pathology and Laboratory Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599 USA
| | - Candice Brinkmeyer-Langford
- Department of Veterinary Integrative Biosciences, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, TX 77843-4458 USA
| | - Hongtu Zhu
- Department of Biostatistics, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599 USA
| | - Joe Palandra
- Rare Disease Research Unit, Pfizer, Inc., Cambridge Park Drive, Cambridge, MA USA
| | - Carl A Morris
- Rare Disease Research Unit, Pfizer, Inc., Cambridge Park Drive, Cambridge, MA USA
| | - Martin A Styner
- Department of Psychiatry, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599 USA ; Department of Computer Science, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599 USA
| | - Kathryn R Wagner
- The Hugo W. Moser Research Institute at Kennedy Krieger Institute and Departments of Neurology and Neuroscience, Johns Hopkins School of Medicine, Baltimore, MD 21205 USA
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29
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Walsh ME, Bhattacharya A, Sataranatarajan K, Qaisar R, Sloane L, Rahman MM, Kinter M, Van Remmen H. The histone deacetylase inhibitor butyrate improves metabolism and reduces muscle atrophy during aging. Aging Cell 2015; 14:957-70. [PMID: 26290460 PMCID: PMC4693467 DOI: 10.1111/acel.12387] [Citation(s) in RCA: 204] [Impact Index Per Article: 22.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/26/2015] [Indexed: 12/16/2022] Open
Abstract
Sarcopenia, the loss of skeletal muscle mass and function during aging, is a major contributor to disability and frailty in the elderly. Previous studies found a protective effect of reduced histone deacetylase activity in models of neurogenic muscle atrophy. Because loss of muscle mass during aging is associated with loss of motor neuron innervation, we investigated the potential for the histone deacetylase (HDAC) inhibitor butyrate to modulate age‐related muscle loss. Consistent with previous studies, we found significant loss of hindlimb muscle mass in 26‐month‐old C57Bl/6 female mice fed a control diet. Butyrate treatment starting at 16 months of age wholly or partially protected against muscle atrophy in hindlimb muscles. Butyrate increased muscle fiber cross‐sectional area and prevented intramuscular fat accumulation in the old mice. In addition to the protective effect on muscle mass, butyrate reduced fat mass and improved glucose metabolism in 26‐month‐old mice as determined by a glucose tolerance test. Furthermore, butyrate increased markers of mitochondrial biogenesis in skeletal muscle and whole‐body oxygen consumption without affecting activity. The increase in mass in butyrate‐treated mice was not due to reduced ubiquitin‐mediated proteasomal degradation. However, butyrate reduced markers of oxidative stress and apoptosis and altered antioxidant enzyme activity. Our data is the first to show a beneficial effect of butyrate on muscle mass during aging and suggests HDACs contribute to age‐related muscle atrophy and may be effective targets for intervention in sarcopenia and age‐related metabolic disease.
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Affiliation(s)
- Michael E. Walsh
- Department of Cellular and Structural Biology San Antonio TX 78229
| | - Arunabh Bhattacharya
- Department of Cellular and Structural Biology San Antonio TX 78229
- The Barshop Institute for Longevity and Aging Studies, San Antonio, TX 78245 The University of Texas Health Science Center at San Antonio TX 78229 USA
| | | | - Rizwan Qaisar
- Oklahoma Medical Research Foundation Oklahoma City OK USA
| | - Lauren Sloane
- The Barshop Institute for Longevity and Aging Studies, San Antonio, TX 78245 The University of Texas Health Science Center at San Antonio TX 78229 USA
| | - Md M. Rahman
- Department of Cellular and Structural Biology San Antonio TX 78229
| | - Michael Kinter
- Oklahoma Medical Research Foundation Oklahoma City OK USA
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30
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Meijer JP, Jaspers RT, Rittweger J, Seynnes OR, Kamandulis S, Brazaitis M, Skurvydas A, Pišot R, Šimunič B, Narici MV, Degens H. Single muscle fibre contractile properties differ between body-builders, power athletes and control subjects. Exp Physiol 2015; 100:1331-41. [DOI: 10.1113/ep085267] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2015] [Accepted: 08/26/2015] [Indexed: 12/13/2022]
Affiliation(s)
- J. P. Meijer
- School of Healthcare Science; Manchester Metropolitan University; Manchester UK
- Laboratory for Myology, MOVE Research Institute Amsterdam, Faculty of Human Movement Sciences; VU University Amsterdam; Amsterdam The Netherlands
| | - R. T. Jaspers
- Laboratory for Myology, MOVE Research Institute Amsterdam, Faculty of Human Movement Sciences; VU University Amsterdam; Amsterdam The Netherlands
| | - J. Rittweger
- German Aerospace Center, Institute of Aerospace Medicine and Space Physiology; Cologne Germany
| | | | - S. Kamandulis
- Sports Science and Innovation Institute; Lithuanian Sports University; Kaunas Lithuania
| | - M. Brazaitis
- Sports Science and Innovation Institute; Lithuanian Sports University; Kaunas Lithuania
| | - A. Skurvydas
- Sports Science and Innovation Institute; Lithuanian Sports University; Kaunas Lithuania
| | - R. Pišot
- Institute of Kinesiology Research; University of Primorska; Koper Slovenia
| | - B. Šimunič
- Institute of Kinesiology Research; University of Primorska; Koper Slovenia
| | | | - H. Degens
- School of Healthcare Science; Manchester Metropolitan University; Manchester UK
- Sports Science and Innovation Institute; Lithuanian Sports University; Kaunas Lithuania
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31
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Minderis P, Kilikevicius A, Baltusnikas J, Alhindi Y, Venckunas T, Bunger L, Lionikas A, Ratkevicius A. Myostatin dysfunction is associated with reduction in overload induced hypertrophy of soleus muscle in mice. Scand J Med Sci Sports 2015; 26:894-901. [DOI: 10.1111/sms.12532] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/02/2015] [Indexed: 12/16/2022]
Affiliation(s)
- P. Minderis
- Institute of Sport Science and Innovations; Lithuanian Sports University; Kaunas Lithuania
| | - A. Kilikevicius
- Institute of Sport Science and Innovations; Lithuanian Sports University; Kaunas Lithuania
| | - J. Baltusnikas
- Institute of Sport Science and Innovations; Lithuanian Sports University; Kaunas Lithuania
| | - Y. Alhindi
- School of Medical Sciences; College of Life Sciences and Medicine; University of Aberdeen; Aberdeen Scotland UK
| | - T. Venckunas
- Institute of Sport Science and Innovations; Lithuanian Sports University; Kaunas Lithuania
| | - L. Bunger
- Animal Breeding and Genetics, Animal and Veterinary Sciences group; Scotland's Rural College (SRUC); Edinburgh UK
| | - A. Lionikas
- Institute of Sport Science and Innovations; Lithuanian Sports University; Kaunas Lithuania
- School of Medical Sciences; College of Life Sciences and Medicine; University of Aberdeen; Aberdeen Scotland UK
| | - A. Ratkevicius
- Institute of Sport Science and Innovations; Lithuanian Sports University; Kaunas Lithuania
- School of Medical Sciences; College of Life Sciences and Medicine; University of Aberdeen; Aberdeen Scotland UK
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32
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Baltusnikas J, Kilikevicius A, Venckunas T, Fokin A, Bünger L, Lionikas A, Ratkevicius A. Myostatin dysfunction impairs force generation in extensor digitorum longus muscle and increases exercise-induced protein efflux from extensor digitorum longus and soleus muscles. Appl Physiol Nutr Metab 2015. [DOI: 10.1139/apnm-2014-0513] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Myostatin dysfunction promotes muscle hypertrophy, which can complicate assessment of muscle properties. We examined force generating capacity and creatine kinase (CK) efflux from skeletal muscles of young mice before they reach adult body and muscle size. Isolated soleus (SOL) and extensor digitorum longus (EDL) muscles of Berlin high (BEH) mice with dysfunctional myostatin, i.e., homozygous for inactivating myostatin mutation, and with a wild-type myostatin (BEH+/+) were studied. The muscles of BEH mice showed faster (P < 0.01) twitch and tetanus contraction times compared with BEH+/+ mice, but only EDL displayed lower (P < 0.05) specific force. SOL and EDL of age-matched but not younger BEH mice showed greater exercise-induced CK efflux compared with BEH+/+ mice. In summary, myostatin dysfunction leads to impairment in muscle force generating capacity in EDL and increases susceptibility of SOL and EDL to protein loss after exercise.
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Affiliation(s)
- Juozas Baltusnikas
- Institute of Sports Sciences and Innovation, Lithuanian Sports University, Sporto 6, LT-44221, Kaunas, Lithuania
| | - Audrius Kilikevicius
- Institute of Sports Sciences and Innovation, Lithuanian Sports University, Sporto 6, LT-44221, Kaunas, Lithuania
| | - Tomas Venckunas
- Institute of Sports Sciences and Innovation, Lithuanian Sports University, Sporto 6, LT-44221, Kaunas, Lithuania
| | - Andrej Fokin
- Institute of Sports Sciences and Innovation, Lithuanian Sports University, Sporto 6, LT-44221, Kaunas, Lithuania
| | - Lutz Bünger
- Scotland’s Rural College (SRUC), Edinburgh, UK
| | - Arimantas Lionikas
- School of Medical Sciences, College of Life Sciences and Medicine, University of Aberdeen, Aberdeen, Scotland, UK
| | - Aivaras Ratkevicius
- Institute of Sports Sciences and Innovation, Lithuanian Sports University, Sporto 6, LT-44221, Kaunas, Lithuania
- School of Medical Sciences, College of Life Sciences and Medicine, University of Aberdeen, Aberdeen, Scotland, UK
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Mendias CL, Lynch EB, Gumucio JP, Flood MD, Rittman DS, Van Pelt DW, Roche SM, Davis CS. Changes in skeletal muscle and tendon structure and function following genetic inactivation of myostatin in rats. J Physiol 2015; 593:2037-52. [PMID: 25640143 DOI: 10.1113/jphysiol.2014.287144] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2014] [Accepted: 01/23/2015] [Indexed: 11/08/2022] Open
Abstract
Myostatin is a negative regulator of skeletal muscle and tendon mass. Myostatin deficiency has been well studied in mice, but limited data are available on how myostatin regulates the structure and function of muscles and tendons of larger animals. We hypothesized that, in comparison to wild-type (MSTN(+/+) ) rats, rats in which zinc finger nucleases were used to genetically inactivate myostatin (MSTN(Δ/Δ) ) would exhibit an increase in muscle mass and total force production, a reduction in specific force, an accumulation of type II fibres and a decrease and stiffening of connective tissue. Overall, the muscle and tendon phenotype of myostatin-deficient rats was markedly different from that of myostatin-deficient mice, which have impaired contractility and pathological changes to fibres and their extracellular matrix. Extensor digitorum longus and soleus muscles of MSTN(Δ/Δ) rats demonstrated 20-33% increases in mass, 35-45% increases in fibre number, 20-57% increases in isometric force and no differences in specific force. The insulin-like growth factor-1 pathway was activated to a greater extent in MSTN(Δ/Δ) muscles, but no substantial differences in atrophy-related genes were observed. Tendons of MSTN(Δ/Δ) rats had a 20% reduction in peak strain, with no differences in mass, peak stress or stiffness. The general morphology and gene expression patterns were similar between tendons of both genotypes. This large rodent model of myostatin deficiency did not have the negative consequences to muscle fibres and extracellular matrix observed in mouse models, and suggests that the greatest impact of myostatin in the regulation of muscle mass may not be to induce atrophy directly, but rather to block hypertrophy signalling.
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Affiliation(s)
- Christopher L Mendias
- Department of Orthopaedic Surgery, University of Michigan, Ann Arbor, MI, USA; Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI, USA
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Muscle Quality in Aging: a Multi-Dimensional Approach to Muscle Functioning with Applications for Treatment. Sports Med 2015; 45:641-58. [DOI: 10.1007/s40279-015-0305-z] [Citation(s) in RCA: 88] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
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Horbelt D, Boergermann JH, Chaikuad A, Alfano I, Williams E, Lukonin I, Timmel T, Bullock AN, Knaus P. Small molecules dorsomorphin and LDN-193189 inhibit myostatin/GDF8 signaling and promote functional myoblast differentiation. J Biol Chem 2014; 290:3390-404. [PMID: 25368322 PMCID: PMC4319009 DOI: 10.1074/jbc.m114.604397] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
GDF8, or myostatin, is a member of the TGF-β superfamily of secreted polypeptide growth factors. GDF8 is a potent negative regulator of myogenesis both in vivo and in vitro. We found that GDF8 signaling was inhibited by the small molecule ATP competitive inhibitors dorsomorphin and LDN-193189. These compounds were previously shown to be potent inhibitors of BMP signaling by binding to the BMP type I receptors ALK1/2/3/6. We present the crystal structure of the type II receptor ActRIIA with dorsomorphin and demonstrate that dorsomorphin or LDN-193189 target GDF8 induced Smad2/3 signaling and repression of myogenic transcription factors. As a result, both inhibitors rescued myogenesis in myoblasts treated with GDF8. As revealed by quantitative live cell microscopy, treatment with dorsomorphin or LDN-193189 promoted the contractile activity of myotubular networks in vitro. We therefore suggest these inhibitors as suitable tools to promote functional myogenesis.
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Affiliation(s)
- Daniel Horbelt
- From the Institute for Chemistry-Biochemistry, Freie Universität Berlin, 14195 Berlin, Germany
| | - Jan H Boergermann
- From the Institute for Chemistry-Biochemistry, Freie Universität Berlin, 14195 Berlin, Germany
| | - Apirat Chaikuad
- the Structural Genomics Consortium, University of Oxford, Oxford OX3 7DQ, United Kingdom, and
| | - Ivan Alfano
- the Structural Genomics Consortium, University of Oxford, Oxford OX3 7DQ, United Kingdom, and
| | - Eleanor Williams
- the Structural Genomics Consortium, University of Oxford, Oxford OX3 7DQ, United Kingdom, and
| | - Ilya Lukonin
- From the Institute for Chemistry-Biochemistry, Freie Universität Berlin, 14195 Berlin, Germany
| | - Tobias Timmel
- the Muscle Research Unit, Experimental and Clinical Research Center, 13125 Berlin, Germany
| | - Alex N Bullock
- the Structural Genomics Consortium, University of Oxford, Oxford OX3 7DQ, United Kingdom, and
| | - Petra Knaus
- From the Institute for Chemistry-Biochemistry, Freie Universität Berlin, 14195 Berlin, Germany,
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36
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Aline G, Sotiropoulos A. Srf: A key factor controlling skeletal muscle hypertrophy by enhancing the recruitment of muscle stem cells. BIOARCHITECTURE 2014; 2:88-90. [PMID: 22880147 PMCID: PMC3414385 DOI: 10.4161/bioa.20699] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Adult skeletal muscles adapt their fiber size to workload. We show that serum response factor (Srf) is required for satellite cell-mediated hypertrophic muscle growth. Deletion of Srf from myofibers, and not satellite cells, blunts overload-induced hypertrophy, and impairs satellite cell proliferation and recruitment to pre-existing fibers. We reveal a gene network in which Srf within myofibers modulates interleukin-6 and cyclooxygenase-2/interleukin-4 expressions and therefore exerts a paracrine control of satellite cell functions. In Srf-deleted muscles, in vivo overexpression of interleukin-6 is sufficient to restore satellite cell proliferation, but not satellite cell fusion and overall growth. In contrast, cyclooxygenase-2/interleukin-4 overexpression rescues satellite cell recruitment and muscle growth without affecting satellite cell proliferation, identifying altered fusion as the limiting cellular event. These findings unravel a role for Srf in the translation of mechanical cues applied to myofibers into paracrine signals, which in turn will modulate satellite cell functions and support muscle growth.
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37
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Philippou A, Barton ER. Optimizing IGF-I for skeletal muscle therapeutics. Growth Horm IGF Res 2014; 24:157-163. [PMID: 25002025 PMCID: PMC4665094 DOI: 10.1016/j.ghir.2014.06.003] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/09/2014] [Accepted: 06/09/2014] [Indexed: 12/13/2022]
Abstract
It is virtually undisputed that IGF-I promotes cell growth and survival. However, the presence of several IGF-I isoforms, vast numbers of intracellular signaling components, and multiple receptors results in a complex and highly regulated system by which IGF-I actions are mediated. IGF-I has long been recognized as one of the critical factors for coordinating muscle growth, enhancing muscle repair, and increasing muscle mass and strength. How to optimize this panoply of pathways to drive anabolic processes in muscle as opposed to aberrant growth in other tissues is an area that deserves focus. This review will address how advances in the bioavailability, potency, and tissue response of IGF-I can provide new potential directions for skeletal muscle therapeutics.
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Affiliation(s)
- Anastassios Philippou
- Department of Physiology, Medical School, National and Kapodistrian University of Athens, Athens, Greece
| | - Elisabeth R Barton
- Department of Anatomy and Cell Biology, School of Dental Medicine, and Pennsylvania Muscle Institute, University of Pennsylvania, Philadelphia, PA, USA.
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Mouisel E, Relizani K, Mille-Hamard L, Denis R, Hourdé C, Agbulut O, Patel K, Arandel L, Morales-Gonzalez S, Vignaud A, Garcia L, Ferry A, Luquet S, Billat V, Ventura-Clapier R, Schuelke M, Amthor H. Myostatin is a key mediator between energy metabolism and endurance capacity of skeletal muscle. Am J Physiol Regul Integr Comp Physiol 2014; 307:R444-54. [DOI: 10.1152/ajpregu.00377.2013] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Myostatin (Mstn) participates in the regulation of skeletal muscle size and has emerged as a regulator of muscle metabolism. Here, we hypothesized that lack of myostatin profoundly depresses oxidative phosphorylation-dependent muscle function. Toward this end, we explored Mstn −/− mice as a model for the constitutive absence of myostatin and AAV-mediated overexpression of myostatin propeptide as a model of myostatin blockade in adult wild-type mice. We show that muscles from Mstn −/− mice, although larger and stronger, fatigue extremely rapidly. Myostatin deficiency shifts muscle from aerobic toward anaerobic energy metabolism, as evidenced by decreased mitochondrial respiration, reduced expression of PPAR transcriptional regulators, increased enolase activity, and exercise-induced lactic acidosis. As a consequence, constitutively reduced myostatin signaling diminishes exercise capacity, while the hypermuscular state of Mstn−/− mice increases oxygen consumption and the energy cost of running. We wondered whether these results are the mere consequence of the congenital fiber-type switch toward a glycolytic phenotype of constitutive Mstn −/− mice. Hence, we overexpressed myostatin propeptide in adult mice, which did not affect fiber-type distribution, while nonetheless causing increased muscle fatigability, diminished exercise capacity, and decreased Pparb/d and Pgc1a expression. In conclusion, our results suggest that myostatin endows skeletal muscle with high oxidative capacity and low fatigability, thus regulating the delicate balance between muscle mass, muscle force, energy metabolism, and endurance capacity.
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Affiliation(s)
- Etienne Mouisel
- Institut National de la Santé et de la Recherche Médicale (INSERM)/Paul Sabatier University, UMR 1048, Institute of Metabolic and Cardiovascular Diseases, Obesity Research Laboratory, Toulouse, France
- Sorbonne Universités, Universités Européennes, l'Université Pierre et Marie Curie (UPMC), Paris 06, Myology Center of Research and Institut National de la Santé et de la Recherche Médicale, UMR S974 and Centre National de la Recherche Scientifique, FRE 3617 and Institut de Myologie, Paris, France
| | - Karima Relizani
- Department of Neuropediatrics and NeuroCure Clinical Research Center, Charité Universitätsmedizin Berlin, Berlin, Germany
- Laboratoire “End:icap”, UFR des Sciences de la Santé, Université de Versailles Saint-Quentin-en-Yvelines, France
| | | | - Raphaël Denis
- Université Paris Diderot, Sorbonne Paris Cité, Unité de Biologie Fonctionnelle et Adaptative, CNRS EAC 4413, Paris, France
| | - Christophe Hourdé
- Sorbonne Universités, Universités Européennes, l'Université Pierre et Marie Curie (UPMC), Paris 06, Myology Center of Research and Institut National de la Santé et de la Recherche Médicale, UMR S974 and Centre National de la Recherche Scientifique, FRE 3617 and Institut de Myologie, Paris, France
- Laboratory of Exercise Physiology, University of Savoie, Chambery, France
| | - Onnik Agbulut
- UPMC, Paris 06, Sorbonne Universités, UMR Centre National de la Recherche Scientifique (CNRS) Biological Adaptation and Ageing, Paris, France
| | - Ketan Patel
- School of Biological Sciences, University of Reading, Reading, United Kingdom
| | - Ludovic Arandel
- Sorbonne Universités, Universités Européennes, l'Université Pierre et Marie Curie (UPMC), Paris 06, Myology Center of Research and Institut National de la Santé et de la Recherche Médicale, UMR S974 and Centre National de la Recherche Scientifique, FRE 3617 and Institut de Myologie, Paris, France
| | - Susanne Morales-Gonzalez
- Department of Neuropediatrics and NeuroCure Clinical Research Center, Charité Universitätsmedizin Berlin, Berlin, Germany
| | | | - Luis Garcia
- Laboratoire “End:icap”, UFR des Sciences de la Santé, Université de Versailles Saint-Quentin-en-Yvelines, France
- Laboratoire International Associé - Biothérapies Appliquées aux Handicaps Neuromusculaires, Centre Scientifique de Monaco, Monaco
| | - Arnaud Ferry
- Sorbonne Universités, Universités Européennes, l'Université Pierre et Marie Curie (UPMC), Paris 06, Myology Center of Research and Institut National de la Santé et de la Recherche Médicale, UMR S974 and Centre National de la Recherche Scientifique, FRE 3617 and Institut de Myologie, Paris, France
- Université Paris Descartes, Paris, France
| | - Serge Luquet
- Université Paris Diderot, Sorbonne Paris Cité, Unité de Biologie Fonctionnelle et Adaptative, CNRS EAC 4413, Paris, France
- CNRS, EAC 4413, Paris, France; and
| | | | | | - Markus Schuelke
- Department of Neuropediatrics and NeuroCure Clinical Research Center, Charité Universitätsmedizin Berlin, Berlin, Germany
| | - Helge Amthor
- Sorbonne Universités, Universités Européennes, l'Université Pierre et Marie Curie (UPMC), Paris 06, Myology Center of Research and Institut National de la Santé et de la Recherche Médicale, UMR S974 and Centre National de la Recherche Scientifique, FRE 3617 and Institut de Myologie, Paris, France
- Laboratoire “End:icap”, UFR des Sciences de la Santé, Université de Versailles Saint-Quentin-en-Yvelines, France
- Laboratoire International Associé - Biothérapies Appliquées aux Handicaps Neuromusculaires, Centre Scientifique de Monaco, Monaco
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39
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Moorwood C, Barton ER. Caspase-12 ablation preserves muscle function in the mdx mouse. Hum Mol Genet 2014; 23:5325-41. [PMID: 24879640 DOI: 10.1093/hmg/ddu249] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
Duchenne muscular dystrophy (DMD) is a devastating muscle wasting disease caused by mutations in dystrophin. Several downstream consequences of dystrophin deficiency are triggers of endoplasmic reticulum (ER) stress, including loss of calcium homeostasis, hypoxia and oxidative stress. During ER stress, misfolded proteins accumulate in the ER lumen and the unfolded protein response (UPR) is triggered, leading to adaptation or apoptosis. We hypothesized that ER stress is heightened in dystrophic muscles and contributes to the pathology of DMD. We observed increases in the ER stress markers BiP and cleaved caspase-4 in DMD patient biopsies, compared with controls, and an increase in multiple UPR pathways in muscles of the dystrophin-deficient mdx mouse. We then crossed mdx mice with mice null for caspase-12, the murine equivalent of human caspase-4, which are resistant to ER stress. We found that deleting caspase-12 preserved mdx muscle function, resulting in a 75% recovery of both specific force generation and resistance to eccentric contractions. The compensatory hypertrophy normally found in mdx muscles was normalized in the absence of caspase-12; this was found to be due to decreased fibre sizes, and not to a fibre type shift or a decrease in fibrosis. Fibre central nucleation was not significantly altered in the absence of caspase-12, but muscle fibre degeneration found in the mdx mouse was reduced almost to wild-type levels. In conclusion, we have identified heightened ER stress and abnormal UPR signalling as novel contributors to the dystrophic phenotype. Caspase-4 is therefore a potential therapeutic target for DMD.
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Affiliation(s)
- Catherine Moorwood
- Department of Anatomy and Cell Biology, University of Pennsylvania School of Dental Medicine, Philadelphia, PA, USA and Pennsylvania Muscle Institute, University of Pennsylvania, Philadelphia, PA, USA
| | - Elisabeth R Barton
- Department of Anatomy and Cell Biology, University of Pennsylvania School of Dental Medicine, Philadelphia, PA, USA and Pennsylvania Muscle Institute, University of Pennsylvania, Philadelphia, PA, USA
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40
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Relizani K, Mouisel E, Giannesini B, Hourdé C, Patel K, Morales Gonzalez S, Jülich K, Vignaud A, Piétri-Rouxel F, Fortin D, Garcia L, Blot S, Ritvos O, Bendahan D, Ferry A, Ventura-Clapier R, Schuelke M, Amthor H. Blockade of ActRIIB signaling triggers muscle fatigability and metabolic myopathy. Mol Ther 2014; 22:1423-1433. [PMID: 24861054 DOI: 10.1038/mt.2014.90] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2013] [Accepted: 05/18/2014] [Indexed: 12/26/2022] Open
Abstract
Myostatin regulates skeletal muscle size via the activin receptor IIB (ActRIIB). However, its effect on muscle energy metabolism and energy-dependent muscle function remains largely unexplored. This question needs to be solved urgently since various therapies for neuromuscular diseases based on blockade of ActRIIB signaling are being developed. Here, we show in mice, that 4-month pharmacological abrogation of ActRIIB signaling by treatment with soluble ActRIIB-Fc triggers extreme muscle fatigability. This is associated with elevated serum lactate levels and a severe metabolic myopathy in the mdx mouse, an animal model of Duchenne muscular dystrophy. Blockade of ActRIIB signaling downregulates porin, a crucial ADP/ATP shuttle between cytosol and mitochondrial matrix leading to a consecutive deficiency of oxidative phosphorylation as measured by in vivo Phosphorus Magnetic Resonance Spectroscopy ((31)P-MRS). Further, ActRIIB blockade reduces muscle capillarization, which further compounds the metabolic stress. We show that ActRIIB regulates key determinants of muscle metabolism, such as Pparβ, Pgc1α, and Pdk4 thereby optimizing different components of muscle energy metabolism. In conclusion, ActRIIB signaling endows skeletal muscle with high oxidative capacity and low fatigability. The severe metabolic side effects following ActRIIB blockade caution against deploying this strategy, at least in isolation, for treatment of neuromuscular disorders.
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Affiliation(s)
- Karima Relizani
- Université Pierre et Marie Curie, Institut de Myologie, Unité mixte de recherche UPMC-AIM UM 76, INSERM U 974, CNRS UMR 7215, Paris, France; Department of Neuropediatrics and NeuroCure Clinical Research Center, Charité Universitätsmedizin Berlin, Berlin, Germany; UFR des Sciences de la Santé, Université de Versailles Saint-Quentin-en-Yvelines, Montigny-le-Bretonneux, France
| | - Etienne Mouisel
- Université Pierre et Marie Curie, Institut de Myologie, Unité mixte de recherche UPMC-AIM UM 76, INSERM U 974, CNRS UMR 7215, Paris, France; Current address: Inserm UMR 1048, Université Paul Sabatier, Toulouse, France
| | - Benoit Giannesini
- Aix-Marseille Université, Centre National de la Recherche Scientifique, Centre de Resonance Magnetique Biologique et Medicale UMR 7339, Marseille, France
| | - Christophe Hourdé
- Université Pierre et Marie Curie, Institut de Myologie, Unité mixte de recherche UPMC-AIM UM 76, INSERM U 974, CNRS UMR 7215, Paris, France
| | - Ketan Patel
- School of Biological Sciences, University of Reading, Reading, UK
| | - Susanne Morales Gonzalez
- Department of Neuropediatrics and NeuroCure Clinical Research Center, Charité Universitätsmedizin Berlin, Berlin, Germany
| | - Kristina Jülich
- Department of Neuropediatrics and NeuroCure Clinical Research Center, Charité Universitätsmedizin Berlin, Berlin, Germany
| | - Alban Vignaud
- Université Pierre et Marie Curie, Institut de Myologie, Unité mixte de recherche UPMC-AIM UM 76, INSERM U 974, CNRS UMR 7215, Paris, France; Généthon, 1 bis rue de l'Internationale, Evry, France
| | - France Piétri-Rouxel
- Université Pierre et Marie Curie, Institut de Myologie, Unité mixte de recherche UPMC-AIM UM 76, INSERM U 974, CNRS UMR 7215, Paris, France
| | | | - Luis Garcia
- UFR des Sciences de la Santé, Université de Versailles Saint-Quentin-en-Yvelines, Montigny-le-Bretonneux, France
| | - Stéphane Blot
- Unité de Neurologie, Ecole Nationale Vétérinaire d'Alfort, Université Paris Est, Créteil, France
| | - Olli Ritvos
- Department of Bacteriology and Immunology, Haartman Institute, University of Helsinki, Helsinki, Finland
| | - David Bendahan
- Aix-Marseille Université, Centre National de la Recherche Scientifique, Centre de Resonance Magnetique Biologique et Medicale UMR 7339, Marseille, France
| | - Arnaud Ferry
- Université Pierre et Marie Curie, Institut de Myologie, Unité mixte de recherche UPMC-AIM UM 76, INSERM U 974, CNRS UMR 7215, Paris, France; Université Paris Descartes, Paris, France
| | | | - Markus Schuelke
- Department of Neuropediatrics and NeuroCure Clinical Research Center, Charité Universitätsmedizin Berlin, Berlin, Germany.
| | - Helge Amthor
- Université Pierre et Marie Curie, Institut de Myologie, Unité mixte de recherche UPMC-AIM UM 76, INSERM U 974, CNRS UMR 7215, Paris, France; UFR des Sciences de la Santé, Université de Versailles Saint-Quentin-en-Yvelines, Montigny-le-Bretonneux, France; Service Génétique Médicale, CHU Necker-Enfants Malades, Université Paris Descartes, Paris, France.
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41
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Brisson BK, Spinazzola J, Park S, Barton ER. Viral expression of insulin-like growth factor I E-peptides increases skeletal muscle mass but at the expense of strength. Am J Physiol Endocrinol Metab 2014; 306:E965-74. [PMID: 24569593 PMCID: PMC3989742 DOI: 10.1152/ajpendo.00008.2014] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
Insulin-like growth factor I (IGF-I) is a protein that regulates and promotes growth in skeletal muscle. The IGF-I precursor polypeptide contains a COOH-terminal extension called the E-peptide. Alternative splicing in the rodent produces two isoforms, IA and IB, where the mature IGF-I in both isoforms is identical yet the E-peptides, EA and EB, share less than 50% homology. Recent in vitro studies show that the E-peptides can enhance IGF-I signaling, leading to increased myoblast cell proliferation and migration. To determine the significance of these actions in vivo and to evaluate if they are physiologically beneficial, EA and EB were expressed in murine skeletal muscle via viral vectors. The viral constructs ensured production of E-peptides without the influence of additional IGF-I through an inactivating mutation in mature IGF-I. E-peptide expression altered ERK1/2 and Akt phosphorylation and increased satellite cell proliferation. EB expression resulted in significant muscle hypertrophy that was IGF-I receptor dependent. However, the increased mass was associated with a loss of muscle strength. EA and EB have similar effects in skeletal muscle signaling and on satellite cells, but EB is more potent at increasing muscle mass. Although sustained EB expression may drive hypertrophy, there are significant physiological consequences for muscle.
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Affiliation(s)
- Becky K Brisson
- Department of Anatomy and Cell Biology, School of Dental Medicine, and Pennsylvania Muscle Institute, University of Pennsylvania, Philadelphia, Pennsylvania
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42
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Pallafacchina G, Blaauw B, Schiaffino S. Role of satellite cells in muscle growth and maintenance of muscle mass. Nutr Metab Cardiovasc Dis 2013; 23 Suppl 1:S12-S18. [PMID: 22621743 DOI: 10.1016/j.numecd.2012.02.002] [Citation(s) in RCA: 94] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/16/2011] [Revised: 02/01/2012] [Accepted: 02/06/2012] [Indexed: 01/25/2023]
Abstract
Changes in muscle mass may result from changes in protein turnover, reflecting the balance between protein synthesis and protein degradation, and changes in cell turnover, reflecting the balance between myonuclear accretion and myonuclear loss. Myonuclear accretion, i.e. increase in the number of myonuclei within the muscle fibers, takes place via proliferation and fusion of satellite cells, myogenic stem cells associated to skeletal muscle fibers and involved in muscle regeneration. In developing muscle, satellite cells undergo extensive proliferation and most of them fuse with myofibers, thus contributing to the increase in myonuclei during early postnatal stages. A similar process is induced in adult skeletal muscle by functional overload and exercise. In contrast, satellite cells and myonuclei may undergo apoptosis during muscle atrophy, although it is debated whether myonuclear loss occurs in atrophying muscle. An increase in myofiber size can also occur by changes in protein turnover without satellite cell activation, e.g. in late phases of postnatal development or in some models of muscle hypertrophy. The relative role of protein turnover and cell turnover in muscle adaptation and in the establishment of functional muscle hypertrophy remains to be established. The identification of the signaling pathways mediating satellite cell activation may provide therapeutic targets for combating muscle wasting in a variety of pathological conditions, including cancer cachexia, renal and cardiac failure, neuromuscular diseases, as well as aging sarcopenia.
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Affiliation(s)
- G Pallafacchina
- Venetian Institute of Molecular Medicine (VIMM), Padova, Italy; Consiglio Nazionale delle Ricerche (CNR) Institute of Neurosciences, Padova, Italy; Department of Biomedical Sciences, University of Padova, Padova, Italy
| | - B Blaauw
- Venetian Institute of Molecular Medicine (VIMM), Padova, Italy; Department of Biomedical Sciences, University of Padova, Padova, Italy
| | - S Schiaffino
- Venetian Institute of Molecular Medicine (VIMM), Padova, Italy; Consiglio Nazionale delle Ricerche (CNR) Institute of Neurosciences, Padova, Italy.
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43
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Smith RC, Lin BK. Myostatin inhibitors as therapies for muscle wasting associated with cancer and other disorders. Curr Opin Support Palliat Care 2013; 7:352-60. [PMID: 24157714 PMCID: PMC3819341 DOI: 10.1097/spc.0000000000000013] [Citation(s) in RCA: 109] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
PURPOSE OF REVIEW This review summarizes recent progress in the development of myostatin inhibitors for the treatment of muscle wasting disorders. It also focuses on findings in myostatin biology that may have implications for the development of antimyostatin therapies. RECENT FINDINGS There has been progress in evaluating antimyostatin therapies in animal models of muscle wasting disorders. Some programs have progressed into clinical development with initial results showing positive impact on muscle volume.In normal mice myostatin deficiency results in enlarged muscles with increased total force but decreased specific force (total force/total mass). An increase in myofibrillar protein synthesis without concomitant satellite cell proliferation and fusion leads to muscle hypertrophy with unchanged myonuclear number. A specific force reduction is not observed when atrophied muscle, the predominant therapeutic target of myostatin inhibitor therapy, is made myostatindeficient.Myostatin has been shown to be expressed by a number of tumor cell lines in mice and man. SUMMARY Myostatin inhibition remains a promising therapeutic strategy for a range of muscle wasting disorders.
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Affiliation(s)
- Rosamund C Smith
- aBiotechnology Discovery Research bOncology Business Unit, Eli Lilly and Company
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44
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Egner IM, Bruusgaard JC, Eftestøl E, Gundersen K. A cellular memory mechanism aids overload hypertrophy in muscle long after an episodic exposure to anabolic steroids. J Physiol 2013; 591:6221-30. [PMID: 24167222 DOI: 10.1113/jphysiol.2013.264457] [Citation(s) in RCA: 79] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
Previous strength training with or without the use of anabolic steroids facilitates subsequent re-acquisition of muscle mass even after long intervening periods of inactivity. Based on in vivo and ex vivo microscopy we here propose a cellular memory mechanism residing in the muscle cells. Female mice were treated with testosterone propionate for 14 days, inducing a 66% increase in the number of myonuclei and a 77% increase in fibre cross-sectional area. Three weeks after removing the drug, fibre size was decreased to the same level as in sham treated animals, but the number of nuclei remained elevated for at least 3 months (>10% of the mouse lifespan). At this time, when the myonuclei-rich muscles were exposed to overload-exercise for 6 days, the fibre cross-sectional area increased by 31% while control muscles did not grow significantly. We suggest that the lasting, elevated number of myonuclei constitutes a cellular memory facilitating subsequent muscle overload hypertrophy. Our findings might have consequences for the exclusion time of doping offenders. Since the ability to generate new myonuclei is impaired in the elderly our data also invites speculation that it might be beneficial to perform strength training when young in order to benefit in senescence.
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Affiliation(s)
- Ingrid M Egner
- K. Gundersen: Department of Biosciences, University of Oslo, PO Box 1066 Blindern, N-0316 Oslo, Norway.
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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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46
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Skeletal muscle function during exercise-fine-tuning of diverse subsystems by nitric oxide. Int J Mol Sci 2013; 14:7109-39. [PMID: 23538841 PMCID: PMC3645679 DOI: 10.3390/ijms14047109] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2013] [Revised: 03/17/2013] [Accepted: 03/19/2013] [Indexed: 02/07/2023] Open
Abstract
Skeletal muscle is responsible for altered acute and chronic workload as induced by exercise. Skeletal muscle adaptations range from immediate change of contractility to structural adaptation to adjust the demanded performance capacities. These processes are regulated by mechanically and metabolically induced signaling pathways, which are more or less involved in all of these regulations. Nitric oxide is one of the central signaling molecules involved in functional and structural adaption in different cell types. It is mainly produced by nitric oxide synthases (NOS) and by non-enzymatic pathways also in skeletal muscle. The relevance of a NOS-dependent NO signaling in skeletal muscle is underlined by the differential subcellular expression of NOS1, NOS2, and NOS3, and the alteration of NO production provoked by changes of workload. In skeletal muscle, a variety of highly relevant tasks to maintain skeletal muscle integrity and proper signaling mechanisms during adaptation processes towards mechanical and metabolic stimulations are taken over by NO signaling. The NO signaling can be mediated by cGMP-dependent and -independent signaling, such as S-nitrosylation-dependent modulation of effector molecules involved in contractile and metabolic adaptation to exercise. In this review, we describe the most recent findings of NO signaling in skeletal muscle with a special emphasis on exercise conditions. However, to gain a more detailed understanding of the complex role of NO signaling for functional adaptation of skeletal muscle (during exercise), additional sophisticated studies are needed to provide deeper insights into NO-mediated signaling and the role of non-enzymatic-derived NO in skeletal muscle physiology.
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47
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Qaisar R, Renaud G, Hedstrom Y, Pöllänen E, Ronkainen P, Kaprio J, Alen M, Sipilä S, Artemenko K, Bergquist J, Kovanen V, Larsson L. Hormone replacement therapy improves contractile function and myonuclear organization of single muscle fibres from postmenopausal monozygotic female twin pairs. J Physiol 2013; 591:2333-44. [PMID: 23459759 DOI: 10.1113/jphysiol.2012.250092] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Ageing is associated with a decline in muscle mass and strength leading to increased physical dependency in old age. Postmenopausal women experience a greater decline than men of similar age in parallel with the decrease in female sex steroid hormone production. We recruited six monozygous female twin pairs (55-59 years old) where only one twin pair was on hormone replacement therapy (HRT use = 7.8 ± 4.3 years) to investigate the association of HRT with the cytoplasmic volume supported by individual myonuclei (myonuclear domain (MND) size,) together with specific force at the single fibre level. HRT use was associated with a significantly smaller (∼27%; P < 0.05) mean MND size in muscle fibres expressing the type I but not the IIa myosin heavy chain (MyHC) isoform. In comparison to non-users, higher specific force was recorded in HRT users both in muscle fibres expressing type I (∼27%; P < 0.05) and type IIa (∼23%; P < 0.05) MyHC isoforms. These differences were fibre-type dependent, i.e. the higher specific force in fast-twitch muscle fibres was primarily caused by higher force per cross-bridge while slow-twitch fibres relied on both a higher number and force per cross-bridge. HRT use had no effect on fibre cross-sectional area (CSA), velocity of unloaded shortening (V0) and relative proportion of MyHC isoforms. In conclusion, HRT appears to have significant positive effects on both regulation of muscle contraction and myonuclei organization in postmenopausal women.
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Affiliation(s)
- Rizwan Qaisar
- Department of Neuroscience, Clinical Neurophysiology, Uppsala University, Sweden
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48
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Hong P, Chen K, Huang B, Liu M, Cui M, Rozenberg I, Chaqour B, Pan X, Barton ER, Jiang XC, Siddiqui MAQ. HEXIM1 controls satellite cell expansion after injury to regulate skeletal muscle regeneration. J Clin Invest 2013; 122:3873-87. [PMID: 23023707 DOI: 10.1172/jci62818] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2012] [Accepted: 08/02/2012] [Indexed: 01/07/2023] Open
Abstract
The native capacity of adult skeletal muscles to regenerate is vital to the recovery from physical injuries and dystrophic diseases. Currently, the development of therapeutic interventions has been hindered by the complex regulatory network underlying the process of muscle regeneration. Using a mouse model of skeletal muscle regeneration after injury, we identified hexamethylene bisacetamide inducible 1 (HEXIM1, also referred to as CLP-1), the inhibitory component of the positive transcription elongation factor b (P-TEFb) complex, as a pivotal regulator of skeletal muscle regeneration. Hexim1-haplodeficient muscles exhibited greater mass and preserved function compared with those of WT muscles after injury, as a result of enhanced expansion of satellite cells. Transplanted Hexim1-haplodeficient satellite cells expanded and improved muscle regeneration more effectively than WT satellite cells. Conversely, HEXIM1 overexpression restrained satellite cell proliferation and impeded muscle regeneration. Mechanistically, dissociation of HEXIM1 from P-TEFb and subsequent activation of P-TEFb are required for satellite cell proliferation and the prevention of early myogenic differentiation. These findings suggest a crucial role for the HEXIM1/P-TEFb pathway in the regulation of satellite cell–mediated muscle regeneration and identify HEXIM1 as a potential therapeutic target for degenerative muscular diseases.
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Affiliation(s)
- Peng Hong
- Department of Cell Biology, State University of New York Downstate Medical Center,New York, New York, USA
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49
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Schirwis E, Agbulut O, Vadrot N, Mouisel E, Hourdé C, Bonnieu A, Butler-Browne G, Amthor H, Ferry A. The beneficial effect of myostatin deficiency on maximal muscle force and power is attenuated with age. Exp Gerontol 2012. [PMID: 23201547 DOI: 10.1016/j.exger.2012.11.008] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
The prolonged effect of myostatin deficiency on muscle performance in knockout mice has as yet been only poorly investigated. We have demonstrated that absolute maximal force is increased in 6-month old female and male knockout mice and 2-year old female knockout mice as compared to age- and sex-matched wildtype mice. Similarly, absolute maximal power is increased by myostatin deficiency in 6-month old female and male knockout mice but not in 2-year old female knockout mice. The increases we observed were greater in 6-month old female than in male knockout mice and can primarily result from muscle hypertrophy. In contrast, fatigue resistance was decreased in 6-month old knockout mice of both sexes as compared to age- and sex-matched wildtype mice. Moreover, in contrast to 2-year old female wildtype mice, aging in 2-year old knockout mice reduced absolute maximal force and power of both sexes as compared to their younger counterparts, although muscle weight did not change. These age-related decreases were lower in 2-year old female than in 2-year old male knockout mice. Together these results suggest that the beneficial effect of myostatin deficiency on absolute maximal force and power is greater in young (versus old) mice and female (versus male) mice. Most of these effects of myostatin deficiency are related neither to changes in the concentration of myofibrillar proteins nor to the slow to fast fiber type transition.
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Affiliation(s)
- E Schirwis
- Université Pierre et Marie Curie-Paris6, Sorbonne Universités, UMR S794, INSERM, U974, CNRS UMR7215, Institut de Myologie, Paris F-75013, France
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50
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Frost RA, Lang CH. Multifaceted role of insulin-like growth factors and mammalian target of rapamycin in skeletal muscle. Endocrinol Metab Clin North Am 2012; 41:297-322, vi. [PMID: 22682632 PMCID: PMC3376019 DOI: 10.1016/j.ecl.2012.04.012] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
This review describes the current literature on the interaction between insulin-like growth factors, endocrine hormones, and branched-chain amino acids on muscle physiology in healthy young individuals and during select pathologic conditions. Emphasis is placed on the mechanism by which physical and hormonal signals are transduced at the cellular level to either grow or atrophy skeletal muscle. The key role of the mammalian target of rapamycin and its ability to respond to hypertrophic and atrophic signals informs our understanding how a combination of physical, nutritional, and pharmacologic therapies may be used in tandem to prevent or ameliorate reductions in muscle mass.
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Affiliation(s)
- Robert A. Frost
- Associate Professor, Department of Cellular and Molecular Physiology, Pennsylvania State University College of Medicine, Hershey PA, 17033
- Professor and Vice Chairman, Department of Cellular and Molecular Physiology, Pennsylvania State University College of Medicine, Hershey PA, 17033
| | - Charles H. Lang
- Associate Professor, Department of Cellular and Molecular Physiology, Pennsylvania State University College of Medicine, Hershey PA, 17033
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