1
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Attwaters M, Hughes SM. Cellular and molecular pathways controlling muscle size in response to exercise. FEBS J 2022; 289:1428-1456. [PMID: 33755332 DOI: 10.1111/febs.15820] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2021] [Revised: 02/27/2021] [Accepted: 03/12/2021] [Indexed: 12/14/2022]
Abstract
From the discovery of ATP and motor proteins to synaptic neurotransmitters and growth factor control of cell differentiation, skeletal muscle has provided an extreme model system in which to understand aspects of tissue function. Muscle is one of the few tissues that can undergo both increase and decrease in size during everyday life. Muscle size depends on its contractile activity, but the precise cellular and molecular pathway(s) by which the activity stimulus influences muscle size and strength remain unclear. Four correlates of muscle contraction could, in theory, regulate muscle growth: nerve-derived signals, cytoplasmic calcium dynamics, the rate of ATP consumption and physical force. Here, we summarise the evidence for and against each stimulus and what is known or remains unclear concerning their molecular signal transduction pathways and cellular effects. Skeletal muscle can grow in three ways, by generation of new syncytial fibres, addition of nuclei from muscle stem cells to existing fibres or increase in cytoplasmic volume/nucleus. Evidence suggests the latter two processes contribute to exercise-induced growth. Fibre growth requires increase in sarcolemmal surface area and cytoplasmic volume at different rates. It has long been known that high-force exercise is a particularly effective growth stimulus, but how this stimulus is sensed and drives coordinated growth that is appropriately scaled across organelles remains a mystery.
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Affiliation(s)
- Michael Attwaters
- Randall Centre for Cell and Molecular Biophysics, School of Basic and Medical Biosciences, King's College London, UK
| | - Simon M Hughes
- Randall Centre for Cell and Molecular Biophysics, School of Basic and Medical Biosciences, King's College London, UK
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2
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Chambers PJ, Juracic ES, Fajardo VA, Tupling AR. The role of SERCA and sarcolipin in adaptive muscle remodeling. Am J Physiol Cell Physiol 2022; 322:C382-C394. [PMID: 35044855 DOI: 10.1152/ajpcell.00198.2021] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Sarcolipin (SLN) is a small integral membrane protein that regulates the sarco(endo)plasmic reticulum Ca2+-ATPase (SERCA) pump. When bound to SERCA, SLN reduces the apparent Ca2+ affinity of SERCA and uncouples SERCA Ca2+ transport from its ATP consumption. As such, SLN plays a direct role in altering skeletal muscle relaxation and energy expenditure. Interestingly, the expression of SLN is dynamic during times of muscle adaptation, where large increases in SLN content are found in response to development, atrophy, overload and disease. Several groups have suggested that increases in SLN, especially in dystrophic muscle, are deleterious to muscle function and exacerbate already abhorrent intracellular Ca2+ levels. However, there is also significant evidence to show that increased SLN content is a beneficial adaptive mechanism which protects the SERCA pump and activates Ca2+ signaling and adaptive remodeling during times of cell stress. In this review, we first discuss the role for SLN in healthy muscle during both development and overload, where SLN has been shown to activate Ca2+ signaling to promote mitochondrial biogenesis, fibre type shifts and muscle hypertrophy. Then, with respect to muscle disease, we summarize the discrepancies in the literature as to whether SLN upregulation is adaptive or maladaptive in nature. This review is the first to offer the concept of SLN hormesis in muscle disease, wherein both too much and too little SLN are detrimental to muscle health. Finally, the underlying mechanisms which activate SLN upregulation are discussed, specifically acknowledging a potential positive feedback loop between SLN and Ca2+ signaling molecules.
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Affiliation(s)
- Paige J Chambers
- Department of Kinesiology and Health Sciences, University of Waterloo, Waterloo, Ontario, Canada
| | - Emma S Juracic
- Department of Kinesiology and Health Sciences, University of Waterloo, Waterloo, Ontario, Canada
| | - Val A Fajardo
- Department Department of Kinesiology, Brock University, St. Catharines, Ontario, Canada.,Centre for Bone and Muscle Health, Brock University, St. Catharines, Ontario, Canada
| | - A Russell Tupling
- Department of Kinesiology and Health Sciences, University of Waterloo, Waterloo, Ontario, Canada
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3
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Seto JT, Roeszler KN, Meehan LR, Wood HD, Tiong C, Bek L, Lee SF, Shah M, Quinlan KGR, Gregorevic P, Houweling PJ, North KN. ACTN3 genotype influences skeletal muscle mass regulation and response to dexamethasone. SCIENCE ADVANCES 2021; 7:eabg0088. [PMID: 34215586 PMCID: PMC11060041 DOI: 10.1126/sciadv.abg0088] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/04/2020] [Accepted: 05/19/2021] [Indexed: 06/13/2023]
Abstract
Homozygosity for the common ACTN3 null polymorphism (ACTN3 577X) results in α-actinin-3 deficiency in ~20% of humans worldwide and is linked to reduced sprint and power performance in both elite athletes and the general population. α-Actinin-3 deficiency is also associated with reduced muscle mass, increased risk of sarcopenia, and altered muscle wasting response induced by denervation and immobilization. Here, we show that α-actinin-3 plays a key role in the regulation of protein synthesis and breakdown signaling in skeletal muscle and influences muscle mass from early postnatal development. We also show that α-actinin-3 deficiency reduces the atrophic and anti-inflammatory response to the glucocorticoid dexamethasone in muscle and protects against dexamethasone-induced muscle wasting in female but not male mice. The effects of α-actinin-3 deficiency on muscle mass regulation and response to muscle wasting provide an additional mechanistic explanation for the positive selection of the ACTN3 577X allele in recent human history.
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Affiliation(s)
- Jane T Seto
- Murdoch Children's Research Institute, The Royal Children's Hospital, Melbourne, VIC, Australia
- Department of Paediatrics, University of Melbourne, The Royal Children's Hospital, Melbourne, VIC, Australia
| | - Kelly N Roeszler
- Murdoch Children's Research Institute, The Royal Children's Hospital, Melbourne, VIC, Australia
- Department of Paediatrics, University of Melbourne, The Royal Children's Hospital, Melbourne, VIC, Australia
| | - Lyra R Meehan
- Murdoch Children's Research Institute, The Royal Children's Hospital, Melbourne, VIC, Australia
| | - Harrison D Wood
- Murdoch Children's Research Institute, The Royal Children's Hospital, Melbourne, VIC, Australia
| | - Chrystal Tiong
- Murdoch Children's Research Institute, The Royal Children's Hospital, Melbourne, VIC, Australia
| | - Lucinda Bek
- Murdoch Children's Research Institute, The Royal Children's Hospital, Melbourne, VIC, Australia
- Department of Paediatrics, University of Melbourne, The Royal Children's Hospital, Melbourne, VIC, Australia
| | - Siaw F Lee
- Murdoch Children's Research Institute, The Royal Children's Hospital, Melbourne, VIC, Australia
| | - Manan Shah
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, NSW, Australia
| | - Kate G R Quinlan
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, NSW, Australia
| | - Paul Gregorevic
- Centre for Muscle Research, Department of Physiology, University of Melbourne, Melbourne, VIC, Australia
- Baker Heart and Diabetes Institute, Melbourne, VIC, Australia
- Department of Biochemistry and Molecular Biology, Monash University, Clayton, VIC, Australia
- Department of Neurology, University of Washington, Seattle, WA, USA
| | - Peter J Houweling
- Murdoch Children's Research Institute, The Royal Children's Hospital, Melbourne, VIC, Australia
- Department of Paediatrics, University of Melbourne, The Royal Children's Hospital, Melbourne, VIC, Australia
| | - Kathryn N North
- Murdoch Children's Research Institute, The Royal Children's Hospital, Melbourne, VIC, Australia.
- Department of Paediatrics, University of Melbourne, The Royal Children's Hospital, Melbourne, VIC, Australia
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4
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The Role of Nutri(epi)genomics in Achieving the Body's Full Potential in Physical Activity. Antioxidants (Basel) 2020; 9:antiox9060498. [PMID: 32517297 PMCID: PMC7346155 DOI: 10.3390/antiox9060498] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2020] [Accepted: 06/05/2020] [Indexed: 12/12/2022] Open
Abstract
Physical activity represents a powerful tool to achieve optimal health. The overall activation of several molecular pathways is associated with many beneficial effects, mainly converging towards a reduced systemic inflammation. Not surprisingly, regular activity can contribute to lowering the “epigenetic age”, acting as a modulator of risk toward several diseases and enhancing longevity. Behind this, there are complex molecular mechanisms induced by exercise, which modulate gene expression, also through epigenetic modifications. The exercise-induced epigenetic imprint can be transient or permanent and contributes to the muscle memory, which allows the skeletal muscle adaptation to environmental stimuli previously encountered. Nutrition, through key macro- and micronutrients with antioxidant properties, can play an important role in supporting skeletal muscle trophism and those molecular pathways triggering the beneficial effects of physical activity. Nutrients and antioxidant food components, reversibly altering the epigenetic imprint, have a big impact on the phenotype. This assigns a role of primary importance to nutri(epi)genomics, not only in optimizing physical performance, but also in promoting long term health. The crosstalk between physical activity and nutrition represents a major environmental pressure able to shape human genotypes and phenotypes, thus, choosing the right combination of lifestyle factors ensures health and longevity.
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5
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Moradi F, Copeland EN, Baranowski RW, Scholey AE, Stuart JA, Fajardo VA. Calmodulin-Binding Proteins in Muscle: A Minireview on Nuclear Receptor Interacting Protein, Neurogranin, and Growth-Associated Protein 43. Int J Mol Sci 2020; 21:E1016. [PMID: 32033037 PMCID: PMC7038096 DOI: 10.3390/ijms21031016] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2019] [Revised: 01/27/2020] [Accepted: 01/31/2020] [Indexed: 01/26/2023] Open
Abstract
Calmodulin (CaM) is an important Ca2+-sensing protein with numerous downstream targets that are either CaM-dependant or CaM-regulated. In muscle, CaM-dependent proteins, which are critical regulators of dynamic Ca2+ handling and contractility, include calcineurin (CaN), CaM-dependant kinase II (CaMKII), ryanodine receptor (RyR), and dihydropyridine receptor (DHPR). CaM-regulated targets include genes associated with oxidative metabolism, muscle plasticity, and repair. Despite its importance in muscle, the regulation of CaM-particularly its availability to bind to and activate downstream targets-is an emerging area of research. In this minireview, we discuss recent studies revealing the importance of small IQ motif proteins that bind to CaM to either facilitate (nuclear receptor interacting protein; NRIP) its activation of downstream targets, or sequester (neurogranin, Ng; and growth-associated protein 43, GAP43) CaM away from their downstream targets. Specifically, we discuss recent studies that have begun uncovering the physiological roles of NRIP, Ng, and GAP43 in skeletal and cardiac muscle, thereby highlighting the importance of endogenously expressed CaM-binding proteins and their regulation of CaM in muscle.
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Affiliation(s)
- Fereshteh Moradi
- Department of Biological Sciences, Brock University, St. Catharines, ON L2S 3A1, Canada; (F.M.); (J.A.S.)
| | - Emily N. Copeland
- Centre for Neuroscience, Brock University, St. Catharines, ON L2S 3A1, Canada;
- Centre for Bone and Muscle Health, Brock University, St. Catharines, ON L2S 3A1, Canada;
| | - Ryan W. Baranowski
- Centre for Bone and Muscle Health, Brock University, St. Catharines, ON L2S 3A1, Canada;
- Department of Kinesiology, Brock University, St. Catharines, ON L2S 3A1, Canada;
| | - Aiden E. Scholey
- Department of Kinesiology, Brock University, St. Catharines, ON L2S 3A1, Canada;
| | - Jeffrey A. Stuart
- Department of Biological Sciences, Brock University, St. Catharines, ON L2S 3A1, Canada; (F.M.); (J.A.S.)
| | - Val A. Fajardo
- Centre for Neuroscience, Brock University, St. Catharines, ON L2S 3A1, Canada;
- Centre for Bone and Muscle Health, Brock University, St. Catharines, ON L2S 3A1, Canada;
- Department of Kinesiology, Brock University, St. Catharines, ON L2S 3A1, Canada;
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6
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Fajardo VA, Chambers PJ, Juracic ES, Rietze BA, Gamu D, Bellissimo C, Kwon F, Quadrilatero J, Russell Tupling A. Sarcolipin deletion in mdx mice impairs calcineurin signalling and worsens dystrophic pathology. Hum Mol Genet 2019; 27:4094-4102. [PMID: 30137316 DOI: 10.1093/hmg/ddy302] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2018] [Accepted: 08/15/2018] [Indexed: 12/11/2022] Open
Abstract
Duchenne muscular dystrophy (DMD) is the most severe form of muscular dystrophy affecting 1 in 3500 live male births. Although there is no cure for DMD, therapeutic strategies aimed at enhancing calcineurin signalling and promoting the slow fibre phenotype have shown promise in mdx mice, which is the classical mouse model for DMD. Sarcolipin (SLN) is a small protein that regulates the sarco(endo)plasmic reticulum Ca2+-ATPase pump and its expression is highly upregulated in dystrophic skeletal muscle. We have recently shown that SLN in skeletal muscle amplifies calcineurin signalling thereby increasing myofibre size and the slow fibre phenotype. Therefore, in the present study we sought to determine the physiological impact of genetic Sln deletion in mdx mice, particularly on calcineurin signalling, fibre-type distribution and size and dystrophic pathology. We generated an mdx/Sln-null (mdx/SlnKO) mouse colony and hypothesized that the soleus and diaphragm muscles from these mice would display blunted calcineurin signalling, smaller myofibre sizes, an increased proportion of fast fibres and worsened dystrophic pathology compared with mdx mice. Our results show that calcineurin signalling was impaired in mdx/SlnKO mice as indicated by reductions in utrophin, stabilin-2 and calcineurin expression. In addition, mdx/SlnKO muscles contained smaller myofibres, exhibited a slow-to-fast fibre-type switch that corresponded with reduced expression of mitochondrial proteins and displayed a worsened dystrophic pathology compared with mdx muscles. Altogether, our findings demonstrate a critical role for SLN upregulation in dystrophic muscles and suggest that SLN can be viewed as a potential therapeutic target.
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Affiliation(s)
- Val A Fajardo
- Department of Kinesiology, University of Waterloo, Waterloo, ON N2L 3G1 Canada
| | - Paige J Chambers
- Department of Kinesiology, University of Waterloo, Waterloo, ON N2L 3G1 Canada
| | - Emma S Juracic
- Department of Kinesiology, University of Waterloo, Waterloo, ON N2L 3G1 Canada
| | - Bradley A Rietze
- Department of Kinesiology, University of Waterloo, Waterloo, ON N2L 3G1 Canada
| | - Daniel Gamu
- Department of Kinesiology, University of Waterloo, Waterloo, ON N2L 3G1 Canada
| | | | - Frenk Kwon
- Department of Kinesiology, University of Waterloo, Waterloo, ON N2L 3G1 Canada
| | - Joe Quadrilatero
- Department of Kinesiology, University of Waterloo, Waterloo, ON N2L 3G1 Canada
| | - A Russell Tupling
- Department of Kinesiology, University of Waterloo, Waterloo, ON N2L 3G1 Canada
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7
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Kim Y, Yang DS, Katti P, Glancy B. Protein composition of the muscle mitochondrial reticulum during postnatal development. J Physiol 2019; 597:2707-2727. [PMID: 30919448 PMCID: PMC6826232 DOI: 10.1113/jp277579] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2018] [Accepted: 03/11/2019] [Indexed: 01/24/2023] Open
Abstract
KEY POINTS Muscle mitochondrial networks changed from a longitudinal, fibre parallel orientation to a perpendicular configuration during postnatal development. Mitochondrial dynamics, mitophagy and calcium uptake proteins were abundant during early postnatal development. Mitochondrial biogenesis and oxidative phosphorylation proteins were upregulated throughout muscle development. Postnatal muscle mitochondrial network formation is accompanied by a change in protein expression profile from mitochondria designed for co-ordinated cellular assembly to mitochondria highly specialized for cellular energy metabolism. ABSTRACT Striated muscle mitochondria form connected networks capable of rapid cellular energy distribution. However, the mitochondrial reticulum is not formed at birth and the mechanisms driving network development remain unclear. In the present study, we aimed to establish the network formation timecourse and protein expression profile during postnatal development of the murine muscle mitochondrial reticulum. Two-photon microscopy was used to observe mitochondrial network orientation in tibialis anterior (TA) muscles of live mice at postnatal days (P) 1, 7, 14, 21 and 42, respectively. All muscle fibres maintained a longitudinal, fibre parallel mitochondrial network orientation early in development (P1-7). Mixed networks were most common at P14 but, by P21, almost all fibres had developed the perpendicular mitochondrial orientation observed in mature, glycolytic fibres. Tandem mass tag proteomics were then applied to examine changes in 6869 protein abundances in developing TA muscles. Mitochondrial proteins increased by 32% from P1 to P42. In addition, both nuclear- and mitochondrial-DNA encoded oxidative phosphorylation (OxPhos) components were increased during development, whereas OxPhos assembly factors decreased. Although mitochondrial dynamics and mitophagy were induced at P1-7, mitochondrial biogenesis was enhanced after P14. Moreover, calcium signalling proteins and the mitochondrial calcium uniporter had the highest expression early in postnatal development. In conclusion, mitochondrial networks transform from a fibre parallel to perpendicular orientation during the second and third weeks after birth in murine glycolytic skeletal muscle. This structural transition is accompanied by a change in protein expression profile from mitochondria designed for co-ordinated cellular assembly to mitochondria highly specialized for cellular energy metabolism.
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Affiliation(s)
- Yuho Kim
- National Heart, Lung, and Blood Institute National Institutes of HealthBethesdaMDUSA
| | - Daniel S. Yang
- National Heart, Lung, and Blood Institute National Institutes of HealthBethesdaMDUSA
| | - Prasanna Katti
- National Heart, Lung, and Blood Institute National Institutes of HealthBethesdaMDUSA
| | - Brian Glancy
- National Heart, Lung, and Blood Institute National Institutes of HealthBethesdaMDUSA
- National Institute of Arthritis and Musculoskeletal and Skin DiseasesNational Institutes of HealthBethesdaMDUSA
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8
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Analysis of differential gene expression of the transgenic pig with overexpression of PGC1α in muscle. Mol Biol Rep 2019; 46:3427-3435. [PMID: 30980266 DOI: 10.1007/s11033-019-04805-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2018] [Accepted: 04/09/2019] [Indexed: 10/27/2022]
Abstract
In order to better understand the key regulatory mechanisms of PGC1α in muscle fiber type transition, the RNA-seq was used to compare the change of gene expression in gastrocnemius muscles between wild type pigs and transgenic pigs with overexpression of PGC1α gene in muscle. 371 differentially expressed genes (P ≤ 0.05 and Ratio ≥ 2), including 184 up-regulated genes and 187 down-regulated genes, were identified. Five main signaling pathways including metabolic pathways, ECM-receptor interaction, PPAR signaling pathway, adipocytokine signaling pathway and insulin signaling pathway, were authenticated using KEGG pathway analysis. Our results indicate that the fat metabolism pathway plays an important role in the transformation of muscle fiber types regulated by PGC1α.
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9
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Ravel-Chapuis A, Bélanger G, Côté J, Michel RN, Jasmin BJ. Misregulation of calcium-handling proteins promotes hyperactivation of calcineurin-NFAT signaling in skeletal muscle of DM1 mice. Hum Mol Genet 2017; 26:2192-2206. [PMID: 28369518 DOI: 10.1093/hmg/ddx109] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2016] [Accepted: 03/16/2017] [Indexed: 12/26/2022] Open
Abstract
Myotonic Dystrophy type 1 (DM1) is caused by an expansion of CUG repeats in DMPK mRNAs. This mutation affects alternative splicing through misregulation of RNA-binding proteins. Amongst pre-mRNAs that are mis-spliced, several code for proteins involved in calcium homeostasis suggesting that calcium-handling and signaling are perturbed in DM1. Here, we analyzed expression of such proteins in DM1 mouse muscle. We found that the levels of several sarcoplasmic reticulum proteins (SERCA1, sarcolipin and calsequestrin) are altered, likely contributing to an imbalance in calcium homeostasis. We also observed that calcineurin (CnA) signaling is hyperactivated in DM1 muscle. Indeed, CnA expression and phosphatase activity are both markedly increased in DM1 muscle. Coherent with this, we found that activators of the CnA pathway (MLP, FHL1) are also elevated. Consequently, NFATc1 expression is increased in DM1 muscle and becomes relocalized to myonuclei, together with an up-regulation of its transcriptional targets (RCAN1.4 and myoglobin). Accordingly, DM1 mouse muscles display an increase in oxidative metabolism and fiber hypertrophy. To determine the functional consequences of this CnA hyperactivation, we administered cyclosporine A, an inhibitor of CnA, to DM1 mice. Muscles of treated DM1 mice showed an increase in CUGBP1 levels, and an exacerbation of key alternative splicing events associated with DM1. Finally, inhibition of CnA in cultured human DM1 myoblasts also resulted in a splicing exacerbation of the insulin receptor. Together, these findings show for the first time that calcium-CnA signaling is hyperactivated in DM1 muscle and that such hyperactivation represents a beneficial compensatory adaptation to the disease.
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Affiliation(s)
- Aymeric Ravel-Chapuis
- Department of Cellular and Molecular Medicine and Center for Neuromuscular Disease, Faculty of Medicine, University of Ottawa, Ottawa, ON, Canada
| | - Guy Bélanger
- Department of Cellular and Molecular Medicine and Center for Neuromuscular Disease, Faculty of Medicine, University of Ottawa, Ottawa, ON, Canada
| | - Jocelyn Côté
- Department of Cellular and Molecular Medicine and Center for Neuromuscular Disease, Faculty of Medicine, University of Ottawa, Ottawa, ON, Canada
| | - Robin N Michel
- Department of Exercise Science, Faculty of Arts and Science, Concordia University, Montreal, QC, Canada
| | - Bernard J Jasmin
- Department of Cellular and Molecular Medicine and Center for Neuromuscular Disease, Faculty of Medicine, University of Ottawa, Ottawa, ON, Canada
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10
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Egner IM, Bruusgaard JC, Gundersen K. An apparent lack of effect of satellite cell depletion on hypertrophy could be due to methodological limitations. Response to ‘Methodological issues limit interpretation of negative effects of satellite cell depletion on adult muscle hypertrophy’. Development 2017; 144:1365-1367. [DOI: 10.1242/dev.148163] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Affiliation(s)
- Ingrid M. Egner
- Department of Biosciences, University of Oslo, Blindern, Oslo N-0316, Norway
| | - Jo C. Bruusgaard
- Department of Biosciences, University of Oslo, Blindern, Oslo N-0316, Norway
- Department of Health Sciences, Kristiania University College, P.O. Box 1190, Sentrum, Oslo N-0107, Norway
| | - Kristian Gundersen
- Department of Biosciences, University of Oslo, Blindern, Oslo N-0316, Norway
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11
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Fajardo VA, Gamu D, Mitchell A, Bloemberg D, Bombardier E, Chambers PJ, Bellissimo C, Quadrilatero J, Tupling AR. Sarcolipin deletion exacerbates soleus muscle atrophy and weakness in phospholamban overexpressing mice. PLoS One 2017; 12:e0173708. [PMID: 28278204 PMCID: PMC5344511 DOI: 10.1371/journal.pone.0173708] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2016] [Accepted: 02/24/2017] [Indexed: 11/18/2022] Open
Abstract
Sarcolipin (SLN) and phospholamban (PLN) are two small proteins that regulate the sarco(endo)plasmic reticulum Ca2+-ATPase pumps. In a recent study, we discovered that Pln overexpression (PlnOE) in slow-twitch type I skeletal muscle fibers drastically impaired SERCA function and caused a centronuclear myopathy-like phenotype, severe muscle atrophy and weakness, and an 8 to 9-fold upregulation of SLN protein in the soleus muscles. Here, we sought to determine the physiological role of SLN upregulation, and based on its role as a SERCA inhibitor, we hypothesized that it would represent a maladaptive response that contributes to the SERCA dysfunction and the overall myopathy observed in the PlnOE mice. To this end, we crossed Sln-null (SlnKO) mice with PlnOE mice to generate a PlnOE/SlnKO mouse colony and assessed SERCA function, CNM pathology, in vitro contractility, muscle mass, calcineurin signaling, daily activity and food intake, and proteolytic enzyme activity. Our results indicate that genetic deletion of Sln did not improve SERCA function nor rescue the CNM phenotype, but did result in exacerbated muscle atrophy and weakness, due to a failure to induce type II fiber compensatory hypertrophy and a reduction in total myofiber count. Mechanistically, our findings suggest that impaired calcineurin activation and resultant decreased expression of stabilin-2, and/or impaired autophagic signaling could be involved. Future studies should examine these possibilities. In conclusion, our study demonstrates the importance of SLN upregulation in combating muscle myopathy in the PlnOE mice, and since SLN is upregulated across several myopathies, our findings may reveal SLN as a novel and universal therapeutic target.
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Affiliation(s)
- Val A. Fajardo
- Department of Kinesiology, University of Waterloo, Waterloo, Ontario, Canada, N2L 3G1
| | - Daniel Gamu
- Department of Kinesiology, University of Waterloo, Waterloo, Ontario, Canada, N2L 3G1
| | - Andrew Mitchell
- Department of Kinesiology, University of Waterloo, Waterloo, Ontario, Canada, N2L 3G1
| | - Darin Bloemberg
- Department of Kinesiology, University of Waterloo, Waterloo, Ontario, Canada, N2L 3G1
| | - Eric Bombardier
- Department of Kinesiology, University of Waterloo, Waterloo, Ontario, Canada, N2L 3G1
| | - Paige J. Chambers
- Department of Kinesiology, University of Waterloo, Waterloo, Ontario, Canada, N2L 3G1
| | - Catherine Bellissimo
- Department of Kinesiology, University of Waterloo, Waterloo, Ontario, Canada, N2L 3G1
| | - Joe Quadrilatero
- Department of Kinesiology, University of Waterloo, Waterloo, Ontario, Canada, N2L 3G1
| | - A. Russell Tupling
- Department of Kinesiology, University of Waterloo, Waterloo, Ontario, Canada, N2L 3G1
- * E-mail:
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12
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Eicosapentaenoic and Docosahexaenoic Acid-Enriched High Fat Diet Delays Skeletal Muscle Degradation in Mice. Nutrients 2016; 8:nu8090543. [PMID: 27598198 PMCID: PMC5037530 DOI: 10.3390/nu8090543] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2016] [Revised: 08/22/2016] [Accepted: 08/25/2016] [Indexed: 01/06/2023] Open
Abstract
Low-grade chronic inflammatory conditions such as ageing, obesity and related metabolic disorders are associated with deterioration of skeletal muscle (SkM). Human studies have shown that marine fatty acids influence SkM function, though the underlying mechanisms of action are unknown. As a model of diet-induced obesity, we fed C57BL/6J mice either a high fat diet (HFD) with purified marine fatty acids eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) (HFD-ED), a HFD with corn oil, or normal mouse chow for 8 weeks; and used transcriptomics to identify the molecular effects of EPA and DHA on SkM. Consumption of ED-enriched HFD modulated SkM metabolism through increased gene expression of mitochondrial β-oxidation and slow-fiber type genes compared with HFD-corn oil fed mice. Furthermore, HFD-ED intake increased nuclear localization of nuclear factor of activated T-cells (Nfatc4) protein, which controls fiber-type composition. This data suggests a role for EPA and DHA in mitigating some of the molecular responses due to a HFD in SkM. Overall, the results suggest that increased consumption of the marine fatty acids EPA and DHA may aid in the prevention of molecular processes that lead to muscle deterioration commonly associated with obesity-induced low-grade inflammation.
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13
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Park SY, Yun Y, Lim JS, Kim MJ, Kim SY, Kim JE, Kim IS. Stabilin-2 modulates the efficiency of myoblast fusion during myogenic differentiation and muscle regeneration. Nat Commun 2016; 7:10871. [PMID: 26972991 PMCID: PMC4793076 DOI: 10.1038/ncomms10871] [Citation(s) in RCA: 79] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2015] [Accepted: 01/28/2016] [Indexed: 01/16/2023] Open
Abstract
Myoblast fusion is essential for the formation of skeletal muscle myofibres. Studies have shown that phosphatidylserine is necessary for myoblast fusion, but the underlying mechanism is not known. Here we show that the phosphatidylserine receptor stabilin-2 acts as a membrane protein for myoblast fusion during myogenic differentiation and muscle regeneration. Stabilin-2 expression is induced during myogenic differentiation, and is regulated by calcineurin/NFAT signalling in myoblasts. Forced expression of stabilin-2 in myoblasts is associated with increased myotube formation, whereas deficiency of stabilin-2 results in the formation of small, thin myotubes. Stab2-deficient mice have myofibres with small cross-sectional area and few myonuclei and impaired muscle regeneration after injury. Importantly, myoblasts lacking stabilin-2 have reduced phosphatidylserine-dependent fusion. Collectively, our results show that stabilin-2 contributes to phosphatidylserine-dependent myoblast fusion and provide new insights into the molecular mechanism by which phosphatidylserine mediates myoblast fusion during muscle growth and regeneration. Phosphatidylserine and its receptors are associated with cell-cell fusion. Here, the authors show the phosphatidylserine receptor stabilin-2 is expressed by muscle cells and plays a vital role in myoblast fusion and post-injury muscle regeneration in mice.
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Affiliation(s)
- Seung-Yoon Park
- Department of Biochemistry, School of Medicine, Dongguk University, Gyeongju 780-714, Republic of Korea
| | - Youngeun Yun
- Department of Biochemistry and Cell Biology, School of Medicine, Kyungpook National University, Daegu 700-422, Republic of Korea
| | - Jung-Suk Lim
- Department of Biochemistry, School of Medicine, Dongguk University, Gyeongju 780-714, Republic of Korea
| | - Mi-Jin Kim
- Department of Biochemistry, School of Medicine, Dongguk University, Gyeongju 780-714, Republic of Korea
| | - Sang-Yeob Kim
- Department of Convergence Medicine, University of Ulsan, College of Medicine &Asan Institute for Life Sciences, Asan Medical Center, Seoul 138-736, Republic of Korea
| | - Jung-Eun Kim
- Department of Molecular Medicine, School of Medicine, Kyungpook National University, Daegu 700-422, Republic of Korea
| | - In-San Kim
- Biomedical Research Institute, Korea Institute Science and Technology, Seoul 136-791, Republic of Korea.,KU-KIST school, Korea University, Seoul 136-701, Republic of Korea
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14
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Schroder EA, Harfmann BD, Zhang X, Srikuea R, England JH, Hodge BA, Wen Y, Riley LA, Yu Q, Christie A, Smith JD, Seward T, Wolf Horrell EM, Mula J, Peterson CA, Butterfield TA, Esser KA. Intrinsic muscle clock is necessary for musculoskeletal health. J Physiol 2015; 593:5387-404. [PMID: 26486627 PMCID: PMC4704520 DOI: 10.1113/jp271436] [Citation(s) in RCA: 90] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2015] [Accepted: 10/12/2015] [Indexed: 12/21/2022] Open
Abstract
KEY POINTS The endogenous molecular clock in skeletal muscle is necessary for maintenance of phenotype and function. Loss of Bmal1 solely from adult skeletal muscle (iMSBmal1(-/-) ) results in reductions in specific tension, increased oxidative fibre type and increased muscle fibrosis with no change in feeding or activity. Disruption of the molecular clock in adult skeletal muscle is sufficient to induce changes in skeletal muscle similar to those seen in the Bmal1 knockout mouse (Bmal1(-/-) ), a model of advanced ageing. iMSBmal1(-/-) mice develop increased bone calcification and decreased joint collagen, which in combination with the functional changes in skeletal muscle results in altered gait. This study uncovers a fundamental role for the skeletal muscle clock in musculoskeletal homeostasis with potential implications for ageing. ABSTRACT Disruption of circadian rhythms in humans and rodents has implicated a fundamental role for circadian rhythms in ageing and the development of many chronic diseases including diabetes, cardiovascular disease, depression and cancer. The molecular clock mechanism underlies circadian rhythms and is defined by a transcription-translation feedback loop with Bmal1 encoding a core molecular clock transcription factor. Germline Bmal1 knockout (Bmal1 KO) mice have a shortened lifespan, show features of advanced ageing and exhibit significant weakness with decreased maximum specific tension at the whole muscle and single fibre levels. We tested the role of the molecular clock in adult skeletal muscle by generating mice that allow for the inducible skeletal muscle-specific deletion of Bmal1 (iMSBmal1). Here we show that disruption of the molecular clock, specifically in adult skeletal muscle, is associated with a muscle phenotype including reductions in specific tension, increased oxidative fibre type, and increased muscle fibrosis similar to that seen in the Bmal1 KO mouse. Remarkably, the phenotype observed in the iMSBmal1(-/-) mice was not limited to changes in muscle. Similar to the germline Bmal1 KO mice, we observed significant bone and cartilage changes throughout the body suggesting a role for the skeletal muscle molecular clock in both the skeletal muscle niche and the systemic milieu. This emerging area of circadian rhythms and the molecular clock in skeletal muscle holds the potential to provide significant insight into intrinsic mechanisms of the maintenance of muscle quality and function as well as identifying a novel crosstalk between skeletal muscle, cartilage and bone.
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Affiliation(s)
- Elizabeth A Schroder
- Center for Muscle Biology, University of Kentucky, Lexington, KY, USA
- Department of Physiology, College of Medicine, University of Kentucky, Lexington, KY, USA
| | - Brianna D Harfmann
- Center for Muscle Biology, University of Kentucky, Lexington, KY, USA
- Department of Physiology, College of Medicine, University of Kentucky, Lexington, KY, USA
| | - Xiping Zhang
- Center for Muscle Biology, University of Kentucky, Lexington, KY, USA
- Department of Physiology, College of Medicine, University of Kentucky, Lexington, KY, USA
| | - Ratchakrit Srikuea
- Center for Muscle Biology, University of Kentucky, Lexington, KY, USA
- Department of Physiology, College of Medicine, University of Kentucky, Lexington, KY, USA
| | | | - Brian A Hodge
- Center for Muscle Biology, University of Kentucky, Lexington, KY, USA
- Department of Physiology, College of Medicine, University of Kentucky, Lexington, KY, USA
| | - Yuan Wen
- Center for Muscle Biology, University of Kentucky, Lexington, KY, USA
- Department of Physiology, College of Medicine, University of Kentucky, Lexington, KY, USA
| | - Lance A Riley
- Center for Muscle Biology, University of Kentucky, Lexington, KY, USA
- Department of Physiology, College of Medicine, University of Kentucky, Lexington, KY, USA
| | - Qi Yu
- Department of Physiology, College of Medicine, University of Kentucky, Lexington, KY, USA
| | - Alexander Christie
- Department of Physiology, College of Medicine, University of Kentucky, Lexington, KY, USA
| | - Jeffrey D Smith
- Center for Muscle Biology, University of Kentucky, Lexington, KY, USA
- Department of Physiology, College of Medicine, University of Kentucky, Lexington, KY, USA
| | - Tanya Seward
- Center for Muscle Biology, University of Kentucky, Lexington, KY, USA
| | - Erin M Wolf Horrell
- Center for Muscle Biology, University of Kentucky, Lexington, KY, USA
- Department of Physiology, College of Medicine, University of Kentucky, Lexington, KY, USA
| | - Jyothi Mula
- Center for Muscle Biology, University of Kentucky, Lexington, KY, USA
- College of Health Sciences, University of Kentucky, Lexington, KY, USA
| | - Charlotte A Peterson
- Center for Muscle Biology, University of Kentucky, Lexington, KY, USA
- College of Health Sciences, University of Kentucky, Lexington, KY, USA
| | - Timothy A Butterfield
- Center for Muscle Biology, University of Kentucky, Lexington, KY, USA
- College of Health Sciences, University of Kentucky, Lexington, KY, USA
| | - Karyn A Esser
- Center for Muscle Biology, University of Kentucky, Lexington, KY, USA
- Department of Physiology, College of Medicine, University of Kentucky, Lexington, KY, USA
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15
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Abstract
A growing body of research has demonstrated the effectiveness of exercise (low-intensity resistance training, walking, cycling) combined with blood flow restriction (BFR) for increased muscular strength and hypertrophy. The BFR is achieved via the application of external pressure over the proximal portion of the upper or lower extremities. The external pressure applied is sufficient to maintain arterial inflow while occluding venous outflow of blood distal to the occlusion site. With specific reference to low-intensity resistance training, the ability to significantly increase muscle strength and hypertrophy when combined with BFR is different from the traditional paradigm, which suggests that lifting only higher intensity loads increases such characteristics. The purpose of this review was to discuss the relevant literature with regard to the type and magnitude of acute responses and chronic adaptations associated with BFR exercise protocols vs. traditional non-BFR exercise protocols. Furthermore, the mechanisms that stimulate such responses and adaptations will be discussed in the context of neural, endocrine, and metabolic pathways. Finally, recommendations will be discussed for the practitioner in the prescription of exercise with BFR.
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Affiliation(s)
- Zachary K Pope
- 1Kinesiology and Sports Studies Department, Eastern Illinois University, Charleston, Illinois 2Department of Health Sciences, Lehman College, Bronx, New York
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16
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Calcineurin: a poorly understood regulator of muscle mass. Int J Biochem Cell Biol 2013; 45:2173-8. [PMID: 23838168 DOI: 10.1016/j.biocel.2013.06.029] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2013] [Revised: 06/26/2013] [Accepted: 06/28/2013] [Indexed: 01/14/2023]
Abstract
This review will discuss the existing literature that has examined the role of calcineurin (CnA) in the regulation of skeletal muscle mass in conditions associated with hypertrophic growth or atrophy. Muscle mass is determined by the balance between protein synthesis and degradation which is controlled by a number of intracellular signaling pathways, most notably the insulin/IGF/phosphatidylinositol 3-kinase (PI3K)/Akt system. Despite being activated by IGF-1 and having well-described functions in the determination of muscle fiber phenotypes, calcineurin (CnA), a Ca(2+)-activated serine/threonine phosphatase, and its downstream signaling partners have garnered little attention as a regulator of muscle mass. Compared to other signaling pathways, the relatively few studies that have examined the role of CnA in the regulation of muscle size have produced discordant results. The reasons for these differences is not obvious but may be due to the selective nature of the genetic models studied, fluctuations in the endogenous level of CnA activity in various muscles, and the variable use of CnA inhibitors to inhibit CnA signaling. Despite the inconsistent nature of the outcomes, there is sufficient direct and indirect evidence to conclude that CnA plays a role in the regulation of skeletal muscle mass. This article is part of a Directed Issue entitled: Molecular basis of muscle wasting.
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17
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Mitochondria as a potential regulator of myogenesis. ScientificWorldJournal 2013; 2013:593267. [PMID: 23431256 PMCID: PMC3574753 DOI: 10.1155/2013/593267] [Citation(s) in RCA: 81] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2012] [Accepted: 01/16/2013] [Indexed: 12/24/2022] Open
Abstract
Recent studies have shown that mitochondria play a role in the regulation of myogenesis. Indeed, the abundance, morphology, and functional properties of mitochondria become altered when the myoblasts differentiate into myotubes. For example, mitochondrial mass/volume, mtDNA copy number, and mitochondrial respiration are markedly increased after the onset of myogenic differentiation. Besides, mitochondrial enzyme activity is also increased, suggesting that the metabolic shift from glycolysis to oxidative phosphorylation as the major energy source occurs during myogenic differentiation. Several lines of evidence suggest that impairment of mitochondrial function and activity blocks myogenic differentiation. However, yet little is known about the molecular mechanisms underlying the regulation of myogenesis by mitochondria. Understanding how mitochondria are involved in myogenesis will provide a valuable insight into the underlying mechanisms that regulate the maintenance of cellular homeostasis. Here, we will summarize the current knowledge regarding the role of mitochondria as a potential regulator of myogenesis.
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Umeki D, Ohnuki Y, Mototani Y, Shiozawa K, Fujita T, Nakamura Y, Saeki Y, Okumura S. Effects of Chronic Akt/mTOR Inhibition by Rapamycin on Mechanical Overload–Induced Hypertrophy and Myosin Heavy Chain Transition in Masseter Muscle. J Pharmacol Sci 2013; 122:278-88. [DOI: 10.1254/jphs.12195fp] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022] Open
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19
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Schoenfeld BJ. Does Exercise-Induced Muscle Damage Play a Role in Skeletal Muscle Hypertrophy? J Strength Cond Res 2012; 26:1441-53. [DOI: 10.1519/jsc.0b013e31824f207e] [Citation(s) in RCA: 124] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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20
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Joanne P, Hourdé C, Ochala J, Caudéran Y, Medja F, Vignaud A, Mouisel E, Hadj-Said W, Arandel L, Garcia L, Goyenvalle A, Mounier R, Zibroba D, Sakamato K, Butler-Browne G, Agbulut O, Ferry A. Impaired adaptive response to mechanical overloading in dystrophic skeletal muscle. PLoS One 2012; 7:e35346. [PMID: 22511986 PMCID: PMC3325198 DOI: 10.1371/journal.pone.0035346] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2011] [Accepted: 03/14/2012] [Indexed: 11/25/2022] Open
Abstract
Dystrophin contributes to force transmission and has a protein-scaffolding role for a variety of signaling complexes in skeletal muscle. In the present study, we tested the hypothesis that the muscle adaptive response following mechanical overloading (ML) would be decreased in MDX dystrophic muscle lacking dystrophin. We found that the gains in muscle maximal force production and fatigue resistance in response to ML were both reduced in MDX mice as compared to healthy mice. MDX muscle also exhibited decreased cellular and molecular muscle remodeling (hypertrophy and promotion of slower/oxidative fiber type) in response to ML, and altered intracellular signalings involved in muscle growth and maintenance (mTOR, myostatin, follistatin, AMPKα1, REDD1, atrogin-1, Bnip3). Moreover, dystrophin rescue via exon skipping restored the adaptive response to ML. Therefore our results demonstrate that the adaptive response in response to ML is impaired in dystrophic MDX muscle, most likely because of the dystrophin crucial role.
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Affiliation(s)
- Pierre Joanne
- Université Paris Diderot, Sorbonne Paris Cité, CNRS EAC4413, Unit of Functional and Adaptive Biology, Laboratory of Stress and Pathologies of the Cytoskeleton, Paris, France
| | - Christophe Hourdé
- Université Pierre et Marie Curie-Paris6, Sorbonne Universités, UMR S794, INSERM U974, CNRS UMR7215, Institut de Myologie, Paris, France
| | - Julien Ochala
- Department of Neuroscience, Uppsala University, Uppsala, Sweden
| | - Yvain Caudéran
- Université Pierre et Marie Curie-Paris6, Sorbonne Universités, UMR S794, INSERM U974, CNRS UMR7215, Institut de Myologie, Paris, France
| | - Fadia Medja
- Université Pierre et Marie Curie-Paris6, Sorbonne Universités, UMR S794, INSERM U974, CNRS UMR7215, Institut de Myologie, Paris, France
| | - Alban Vignaud
- Université Pierre et Marie Curie-Paris6, Sorbonne Universités, UMR S794, INSERM U974, CNRS UMR7215, Institut de Myologie, Paris, France
| | - Etienne Mouisel
- Université Pierre et Marie Curie-Paris6, Sorbonne Universités, UMR S794, INSERM U974, CNRS UMR7215, Institut de Myologie, Paris, France
| | - Wahiba Hadj-Said
- Université Pierre et Marie Curie-Paris6, Sorbonne Universités, UMR S794, INSERM U974, CNRS UMR7215, Institut de Myologie, Paris, France
| | - Ludovic Arandel
- Université Pierre et Marie Curie-Paris6, Sorbonne Universités, UMR S794, INSERM U974, CNRS UMR7215, Institut de Myologie, Paris, France
| | - Luis Garcia
- Université Pierre et Marie Curie-Paris6, Sorbonne Universités, UMR S794, INSERM U974, CNRS UMR7215, Institut de Myologie, Paris, France
| | - Aurélie Goyenvalle
- Université Pierre et Marie Curie-Paris6, Sorbonne Universités, UMR S794, INSERM U974, CNRS UMR7215, Institut de Myologie, Paris, France
| | - Rémi Mounier
- Université Paris Descartes, Sorbonne Paris Cité, INSERM U1016, CNRS UMR8104, Institut Cochin, Paris, France
| | - Daria Zibroba
- MRC Protein Phosphorylation Unit, College of Life Sciences, University of Dundee, Dundee, United Kingdom
| | - Kei Sakamato
- MRC Protein Phosphorylation Unit, College of Life Sciences, University of Dundee, Dundee, United Kingdom
| | - Gillian Butler-Browne
- Université Pierre et Marie Curie-Paris6, Sorbonne Universités, UMR S794, INSERM U974, CNRS UMR7215, Institut de Myologie, Paris, France
| | - Onnik Agbulut
- Université Paris Diderot, Sorbonne Paris Cité, CNRS EAC4413, Unit of Functional and Adaptive Biology, Laboratory of Stress and Pathologies of the Cytoskeleton, Paris, France
| | - Arnaud Ferry
- Université Pierre et Marie Curie-Paris6, Sorbonne Universités, UMR S794, INSERM U974, CNRS UMR7215, Institut de Myologie, Paris, France
- Université Paris Descartes, Sorbonne Paris Cité, Paris, France
- * E-mail:
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21
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Martins KJB, St-Louis M, Murdoch GK, MacLean IM, McDonald P, Dixon WT, Putman CT, Michel RN. Nitric oxide synthase inhibition prevents activity-induced calcineurin-NFATc1 signalling and fast-to-slow skeletal muscle fibre type conversions. J Physiol 2012; 590:1427-42. [PMID: 22219342 DOI: 10.1113/jphysiol.2011.223370] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
The calcineurin–NFAT (nuclear factor of activated T-cells) signalling pathway is involved in the regulation of activity-dependent skeletal muscle myosin heavy chain (MHC) isoform type expression. Emerging evidence indicates that nitric oxide (NO) may play a critical role in this regulatory pathway. Thus, the purpose of this study was to investigate the role of NO in activity-induced calcineurin–NFATc1 signalling leading to skeletal muscle faster-to-slower fibre type transformations in vivo. Endogenous NO production was blocked by administering L-NAME (0.75 mg ml(−1)) in drinking water throughout 0, 1, 2, 5 or 10 days of chronic low-frequency stimulation (CLFS; 10 Hz, 12 h day(−1)) of rat fast-twitch muscles (L+Stim; n = 30) and outcomes were compared with control rats receiving only CLFS (Stim; n = 30). Western blot and immunofluorescence analyses revealed that CLFS induced an increase in NFATc1 dephosphorylation and nuclear localisation, sustained by glycogen synthase kinase (GSK)-3β phosphorylation in Stim, which were all abolished in L+Stim. Moreover, real-time RT-PCR revealed that CLFS induced an increased expression of MHC-I, -IIa and -IId(x) mRNAs in Stim that was abolished in L+Stim. SDS-PAGE and immunohistochemical analyses revealed that CLFS induced faster-to-slower MHC protein and fibre type transformations, respectively, within the fast fibre population of both Stim and L+Stim groups. The final fast type IIA to slow type I transformation, however, was prevented in L+Stim. It is concluded that NO regulates activity-induced MHC-based faster-to-slower fibre type transformations at the transcriptional level via inhibitory GSK-3β-induced facilitation of calcineurin–NFATc1 nuclear accumulation in vivo, whereas transformations within the fast fibre population may also involve translational control mechanisms independent of NO signalling.
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Affiliation(s)
- Karen J B Martins
- Exercise Biochemistry Laboratory, Faculty of Physical Education and Recreation, University of Alberta, Edmonton, AB, Canada T6G 2H9
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HE ZIHONG, HU YANG, LI YANCHUN, YVERT THOMAS, SANTIAGO CATALINA, GÓMEZ-GALLEGO FÉLIX, RUIZ JONATANR, LUCIA ALEJANDRO. Are Calcineurin Genes Associated with Athletic Status? A Function, Replication Study. Med Sci Sports Exerc 2011; 43:1433-40. [DOI: 10.1249/mss.0b013e31820e7f38] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
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24
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Meissner JD, Freund R, Krone D, Umeda PK, Chang KC, Gros G, Scheibe RJ. Extracellular signal-regulated kinase 1/2-mediated phosphorylation of p300 enhances myosin heavy chain I/beta gene expression via acetylation of nuclear factor of activated T cells c1. Nucleic Acids Res 2011; 39:5907-25. [PMID: 21498542 PMCID: PMC3152325 DOI: 10.1093/nar/gkr162] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
The nuclear factor of activated T-cells (NFAT) c1 has been shown to be essential for Ca2+-dependent upregulation of myosin heavy chain (MyHC) I/β expression during skeletal muscle fiber type transformation. Here, we report activation of extracellular signal-regulated kinase (ERK) 1/2 in Ca2+-ionophore-treated C2C12 myotubes and electrostimulated soleus muscle. Activated ERK1/2 enhanced NFATc1-dependent upregulation of a −2.4 kb MyHCI/β promoter construct without affecting subcellular localization of endogenous NFATc1. Instead, ERK1/2-augmented phosphorylation of transcriptional coactivator p300, promoted its recruitment to NFATc1 and increased NFATc1–DNA binding to a NFAT site of the MyHCI/β promoter. In line, inhibition of ERK1/2 signaling abolished the effects of p300. Comparison between wild-type p300 and an acetyltransferase-deficient mutant (p300DY) indicated increased NFATc1–DNA binding as a consequence of p300-mediated acetylation of NFATc1. Activation of the MyHCI/β promoter by p300 depends on two conserved acetylation sites in NFATc1, which affect DNA binding and transcriptional stimulation. NFATc1 acetylation occurred in Ca2+-ionophore treated C2C12 myotubes or electrostimulated soleus. Finally, endogenous MyHCI/β gene expression in C2C12 myotubes was strongly inhibited by p300DY and a mutant deficient in ERK phosphorylation sites. In conclusion, ERK1/2-mediated phosphorylation of p300 is crucial for enhancing NFATc1 transactivation function by acetylation, which is essential for Ca2+-induced MyHCI/β expression.
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Affiliation(s)
- Joachim D Meissner
- Department of Vegetative Physiology, Institute of Biochemistry, Hannover Medical School, D-30625 Hannover, Germany
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25
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Qin W, Bauman WA, Cardozo C. Bone and muscle loss after spinal cord injury: organ interactions. Ann N Y Acad Sci 2010; 1211:66-84. [PMID: 21062296 DOI: 10.1111/j.1749-6632.2010.05806.x] [Citation(s) in RCA: 125] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Spinal cord injury (SCI) results in paralysis and marked loss of skeletal muscle and bone below the level of injury. Modest muscle activity prevents atrophy, whereas much larger--and as yet poorly defined--bone loading seems necessary to prevent bone loss. Once established, bone loss may be irreversible. SCI is associated with reductions in growth hormone, IGF-1, and testosterone, deficiencies likely to exacerbate further loss of muscle and bone. Reduced muscle mass and inactivity are assumed to be contributors to the high prevalence of insulin resistance and diabetes in this population. Alterations in muscle gene expression after SCI share common features with other muscle loss states, but even so, show distinct profiles, possibly reflecting influences of neuromuscular activity due to spasticity. Changes in bone cells and markers after SCI have similarities with other conditions of unloading, although after SCI these changes are much more dramatic, perhaps reflecting the much greater magnitude of unloading. Adiposity and marrow fat are increased after SCI with intriguing, though poorly understood, implications for the function of skeletal muscle and bone cells.
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Affiliation(s)
- Weiping Qin
- Center of Excellence for the Medical Consequences of Spinal Cord Injury, James J. Peters Veterans Affairs Medical Center, Bronx, New York, USA.
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26
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The functional role of calcineurin in hypertrophy, regeneration, and disorders of skeletal muscle. J Biomed Biotechnol 2010; 2010:721219. [PMID: 20379369 PMCID: PMC2850156 DOI: 10.1155/2010/721219] [Citation(s) in RCA: 83] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2009] [Accepted: 02/09/2010] [Indexed: 12/27/2022] Open
Abstract
Skeletal muscle uses calcium as a second messenger to respond and adapt to environmental stimuli. Elevations in intracellular calcium levels activate calcineurin, a serine/threonine phosphatase, resulting in the expression of a set of genes involved in the maintenance, growth, and remodeling of skeletal muscle. In this review, we discuss the effects of calcineurin activity on hypertrophy, regeneration, and disorders of skeletal muscle. Calcineurin is a potent regulator of muscle remodeling, enhancing the differentiation through upregulation of myogenin or MEF2A and downregulation of the Id1 family and myostatin. Foxo may also be a downstream candidate for a calcineurin signaling molecule during muscle regeneration. The strategy of controlling the amount of calcineurin may be effective for the treatment of muscular disorders such as DMD, UCMD, and LGMD. Activation of calcineurin produces muscular hypertrophy of the slow-twitch soleus muscle but not fast-twitch muscles.
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27
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Are calcineurin genes associated with endurance phenotype traits? Eur J Appl Physiol 2010; 109:359-69. [DOI: 10.1007/s00421-010-1361-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/11/2010] [Indexed: 10/19/2022]
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28
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Pogozelski AR, Geng T, Li P, Yin X, Lira VA, Zhang M, Chi JT, Yan Z. p38gamma mitogen-activated protein kinase is a key regulator in skeletal muscle metabolic adaptation in mice. PLoS One 2009; 4:e7934. [PMID: 19936205 PMCID: PMC2775956 DOI: 10.1371/journal.pone.0007934] [Citation(s) in RCA: 119] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2009] [Accepted: 10/19/2009] [Indexed: 12/20/2022] Open
Abstract
Regular endurance exercise induces skeletal muscle contractile and metabolic adaptations, conferring salutary health benefits, such as protection against the metabolic syndrome. The plasticity of skeletal muscle has been extensively investigated, but how the adaptive processes are precisely controlled is largely unknown. Using muscle-specific gene deletion in mice, we now show that p38gamma mitogen-activated protein kinase (MAPK), but not p38alpha and p38beta, is required for endurance exercise-induced mitochondrial biogenesis and angiogenesis, whereas none of the p38 isoforms are required for IIb-to-IIa fiber-type transformation. These phenotypic findings were further supported by microarray and real-time PCR analyses revealing contractile activity-dependent p38gamma target genes, including peroxisome proliferator-activated receptor gamma co-activator-1alpha (Pgc-1alpha) and vascular endothelial growth factor (Vegf), in skeletal muscle following motor nerve stimulation. Gene transfer-mediated overexpression of a dominant negative form of p38gamma, but not that of p38alpha or p38beta, blocked motor nerve stimulation-induced Pgc-1alpha transcription. These findings provide direct evidence for an obligated role of p38gamma MAPK-PGC-1alpha regulatory axis in endurance exercise-induced metabolic adaptation, but not contractile adaptation, in skeletal muscle.
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Affiliation(s)
- Andrew R. Pogozelski
- Department of Medicine, Duke University Medical Center, Durham, North Carolina, United States of America
| | - Tuoyu Geng
- Department of Medicine, Duke University Medical Center, Durham, North Carolina, United States of America
| | - Ping Li
- Department of Medicine, Duke University Medical Center, Durham, North Carolina, United States of America
| | - Xinhe Yin
- Department of Medicine, Duke University Medical Center, Durham, North Carolina, United States of America
| | - Vitor A. Lira
- Department of Medicine-Cardiovascular Medicine, University of Virginia, Charlottesville, Virginia, United States of America
- Center for Skeletal Muscle Research at Robert M. Berne Cardiovascular Research Center, University of Virginia, Charlottesville, Virginia, United States of America
| | - Mei Zhang
- Department of Medicine, Duke University Medical Center, Durham, North Carolina, United States of America
| | - Jen-Tsan Chi
- Institute for Genome Sciences and Policy, Duke University Medical Center, Durham, North Carolina, United States of America
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, North Carolina, United States of America
| | - Zhen Yan
- Department of Medicine, Duke University Medical Center, Durham, North Carolina, United States of America
- Department of Medicine-Cardiovascular Medicine, University of Virginia, Charlottesville, Virginia, United States of America
- Center for Skeletal Muscle Research at Robert M. Berne Cardiovascular Research Center, University of Virginia, Charlottesville, Virginia, United States of America
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Pandorf CE, Jiang WH, Qin AX, Bodell PW, Baldwin KM, Haddad F. Calcineurin plays a modulatory role in loading-induced regulation of type I myosin heavy chain gene expression in slow skeletal muscle. Am J Physiol Regul Integr Comp Physiol 2009; 297:R1037-48. [PMID: 19657098 DOI: 10.1152/ajpregu.00349.2009] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
The role of calcineurin (Cn) in skeletal muscle fiber-type expression has been a subject of great interest because of reports indicating that it controls the slow muscle phenotype. To delineate the role of Cn in phenotype remodeling, particularly its role in driving expression of the type I myosin heavy chain (MHC) gene, we used a novel strategy whereby a profound transition from fast to slow fiber type is induced and examined in the absence and presence of cyclosporin A (CsA), a Cn inhibitor. To induce the fast-to-slow transition, we first subjected rats to 7 days of hindlimb suspension (HS) + thyroid hormone [triiodothyronine (T(3))] to suppress nearly all expression of type I MHC mRNA in the soleus muscle. HS + T(3) was then withdrawn, and rats resumed normal ambulation and thyroid state, during which vehicle or CsA (30 mg x kg(-1) x day(-1)) was administered for 7 or 14 days. The findings demonstrate that, despite significant inhibition of Cn, pre-mRNA, mRNA, and protein abundance of type I MHC increased markedly during reloading relative to HS + T(3) (P < 0.05). Type I MHC expression was, however, attenuated by CsA compared with vehicle treatment. In addition, type IIa and IIx MHC pre-mRNA, mRNA, and relative protein levels were increased in Cn-treated compared with vehicle-treated rats. These findings indicate that Cn has a modulatory role in MHC transcription, rather than a role as a primary regulator of slow MHC gene expression.
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Affiliation(s)
- Clay E Pandorf
- Department of Physiology and Biophysics, University of California, Irvine, Irvine, California 92697, USA
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30
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Mallinson J, Meissner J, Chang KC. Chapter 2. Calcineurin signaling and the slow oxidative skeletal muscle fiber type. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2009; 277:67-101. [PMID: 19766967 DOI: 10.1016/s1937-6448(09)77002-9] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Calcineurin, also known as protein phosphatase 2B (PP2B), is a calcium-calmodulin-dependent phosphatase. It couples intracellular calcium to dephosphorylate selected substrates resulting in diverse biological consequences depending on cell type. In mammals, calcineurin's functions include neuronal growth, development of cardiac valves and hypertrophy, activation of lymphocytes, and the regulation of ion channels and enzymes. This chapter focuses on the key roles of calcineurin in skeletal muscle differentiation, regeneration, and fiber type conversion to an oxidative state, all of which are crucial to muscle development, metabolism, and functional adaptations. It seeks to integrate the current knowledge of calcineurin signaling in skeletal muscle and its interactions with other prominent regulatory pathways and their signaling intermediates to form a molecular overview that could provide directions for possible future exploitations in human metabolic health.
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Affiliation(s)
- Joanne Mallinson
- School of Veterinary Medicine and Science, University of Nottingham, Sutton Bonington, UK
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31
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Sakuma K, Akiho M, Nakashima H, Nakao R, Hirata M, Inashima S, Yamaguchi A, Yasuhara M. Cyclosporin A modulates cellular localization of MEF2C protein and blocks fiber hypertrophy in the overloaded soleus muscle of mice. Acta Neuropathol 2008; 115:663-74. [PMID: 18369646 DOI: 10.1007/s00401-008-0371-5] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2007] [Revised: 03/13/2008] [Accepted: 03/14/2008] [Indexed: 12/26/2022]
Abstract
The molecular signaling pathway linked to hypertrophy of the anti-gravity/postural soleus muscle after mechanical overloading has not been identified. Using reverse transcription-polymerase chain reaction (RT-PCR), Western blot, and immunohistochemical analyses, we investigated whether the amounts of myocyte enhancer factor (MEF)2C, MEF2D, and myogenin change in the mechanically overloaded soleus muscle after treatment with the calcineurin inhibitor cyclosporine A (CsA). Adult male ICR mice were subjected to a surgical ablation of the gastrocnemius muscle and treated with either CsA (25 mg/kg) or vehicle, once daily. They were killed at 2, 4, 7, 10, and 14 days post-injury. Mechanical overloading resulted in a significant increase in the wet weight and the cross-sectional area of slow and fast fibers of the soleus muscle in placebo-treated mice but not CsA-treated mice. RT-PCR analysis did not show a marked difference in MEF2C and MEF2D mRNA levels in the overloaded soleus muscle in placebo- or CsA-administered mice. After 2 days of mechanical overloading, we observed co-localization of MEF2C and myogenin in several mononuclear cells under both conditions. These MEF2C-positive mononuclear cells also possessed immunoreactivity for c-Met, a satellite cell marker. At 4 days, mechanical overloading induced marked expression of MEF2C but not MEF2D in the subsarcolemmal region in a group of myotubes and/or myofibers. Such a MEF2C-positive region emerged less often in the hypertrophied soleus muscle subjected to the treatment with CsA. At 7 days, we observed many mononuclear cells possessing both MEF2C and myogenin protein in mice treated with CsA, but not the placebo. Our results demonstrated that CsA treatment modulates the amount and cellular localization of MEF2C protein. The modulation of MEF2C by CsA treatment may inhibit the hypertrophic process in the soleus muscle after mechanical overloading.
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Affiliation(s)
- Kunihiro Sakuma
- Health Science Center, Toyohashi University of Technology, 1-1 Hibarigaoka, Tenpaku-cho, Toyohashi 441-8580, Japan.
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32
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Michel RN, Chin ER, Chakkalakal JV, Eibl JK, Jasmin BJ. Ca2+/calmodulin-based signalling in the regulation of the muscle fibre phenotype and its therapeutic potential via modulation of utrophin A and myostatin expression. Appl Physiol Nutr Metab 2008; 32:921-9. [PMID: 18059617 DOI: 10.1139/h07-093] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Ca2+ signalling plays an important role in excitation-contraction coupling and the resultant force output of skeletal muscle. It is also known to play a crucial role in modulating both short- and long-term muscle cellular phenotypic adaptations associated with these events. Ca2+ signalling via the Ca2+/calmodulin (CaM)-dependent phosphatase calcineurin (CnA) and via Ca2+/CaM-dependent kinases, such as CaMKI and CaMKII, is known to regulate hypertrophic growth in response to overload, to direct slow versus fast fibre gene expression, and to contribute to mitochondrial biogenesis. The CnA- and CaMK-dependent regulation of the downstream transcription factors nuclear factor of activated T cells (NFAT) and myocyte-specific enhancer factor 2 are known to activate muscle-specific genes associated with a slower, more oxidative fibre phenotype. We have also recently shown the expression of utrophin A, a cytoskeletal protein that accumulates at the neuromuscular junction and plays a role in maturation of the postsynaptic apparatus, to be regulated by CnA-NFAT and Ca2+/CaM signalling. This regulation is fibre-type specific and potentiated by interactions with the transcriptional regulators and coactivators GA binding protein (also known as nuclear respiratory factor 2) and peroxisome proliferator-activated receptor-gamma coactivator 1 alpha. Another downstream target of CnA signalling may be myostatin, a transforming growth factor-beta family member that is a negative regulator of muscle growth. While the list of the downstream targets of CnA/NFAT- and Ca2+/CaM-dependent signalling is emerging, the precise interaction of these pathways with the Ca2+-independent pathways p38 mitogen-activated protein kinase, extracellular signal-regulated kinases 1 and 2, phosphoinositide-3 kinase, and protein kinase B (Akt/PKB) must also be considered when deciphering fibre responses and plasticity to altered contractile load.
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Affiliation(s)
- Robin N Michel
- Department of Chemistry and Biochemistry,Concordia University, The Richard J. Renaud Science Complex, Montreal, QC H4B 1R6, Canada.
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33
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Favier FB, Benoit H, Freyssenet D. Cellular and molecular events controlling skeletal muscle mass in response to altered use. Pflugers Arch 2008; 456:587-600. [DOI: 10.1007/s00424-007-0423-z] [Citation(s) in RCA: 91] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2007] [Accepted: 12/06/2007] [Indexed: 12/21/2022]
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34
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Abstract
Skeletal muscle is a malleable tissue capable of altering the type and amount of protein in response to disruptions to cellular homeostasis. The process of exercise-induced adaptation in skeletal muscle involves a multitude of signalling mechanisms initiating replication of specific DNA genetic sequences, enabling subsequent translation of the genetic message and ultimately generating a series of amino acids that form new proteins. The functional consequences of these adaptations are determined by training volume, intensity and frequency, and the half-life of the protein. Moreover, many features of the training adaptation are specific to the type of stimulus, such as the mode of exercise. Prolonged endurance training elicits a variety of metabolic and morphological changes, including mitochondrial biogenesis, fast-to-slow fibre-type transformation and substrate metabolism. In contrast, heavy resistance exercise stimulates synthesis of contractile proteins responsible for muscle hypertrophy and increases in maximal contractile force output. Concomitant with the vastly different functional outcomes induced by these diverse exercise modes, the genetic and molecular mechanisms of adaptation are distinct. With recent advances in technology, it is now possible to study the effects of various training interventions on a variety of signalling proteins and early-response genes in skeletal muscle. Although it cannot presently be claimed that such scientific endeavours have influenced the training practices of elite athletes, these new and exciting technologies have provided insight into how current training techniques result in specific muscular adaptations, and may ultimately provide clues for future and novel training methodologies. Greater knowledge of the mechanisms and interaction of exercise-induced adaptive pathways in skeletal muscle is important for our understanding of the aetiology of disease, maintenance of metabolic and functional capacity with aging, and training for athletic performance. This article highlights the effects of exercise on molecular and genetic mechanisms of training adaptation in skeletal muscle.
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Affiliation(s)
- Vernon G Coffey
- School of Medical Sciences, Exercise Metabolism Group, RMIT University, Melbourne, Victoria, Australia
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35
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Grondard C, Biondi O, Pariset C, Lopes P, Deforges S, Lécolle S, Gaspera BD, Gallien CL, Chanoine C, Charbonnier F. Exercise-induced modulation of calcineurin activity parallels the time course of myofibre transitions. J Cell Physiol 2007; 214:126-35. [PMID: 17559060 DOI: 10.1002/jcp.21168] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
This study establishes a causal link between the limitation of myofibre transitions and modulation of calcineurin activity, during different exercise paradigms. We have designed a new swimming-based training protocol in order to draw a comparison between a high frequency and amplitude exercise (swimming) and low frequency and amplitude exercise (running). We initially analysed the time course of muscle adaptations to a 6- or 12-week swimming- or running-based training exercise program, on two muscles of the mouse calf, the slow-twitch soleus and the fast-twitch plantaris. The magnitude of exercise-induced muscle plasticity proved to be dependent on both the muscle type and the exercise paradigm. In contrast to the running-based training which generated a continuous increase of the slow phenotype throughout a 12-week training program, swimming induced transitions to a slower phenotype which ended after 6 weeks of training. We then compared the time course of the exercise-induced changes in calcineurin activity during muscle adaptation to training. Both exercises induced an initial activation followed by the inhibition of calcineurin. In the muscles of animals submitted to a 12-week swimming-based training, this inhibition was concomitant with the end of myofibre transition. Calcineurin inhibition was a consequence of the inhibition of its catalytic subunit gene expression on one hand, and of the expression increase of the modulatory calcineurin interacting proteins 1 gene (MCIP1), on the other. The present study provides the first experimental cues for an interpretation of muscle phenotypic variation control.
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Affiliation(s)
- Clément Grondard
- Université Paris Descartes, Centre Universitaire des Saints-Pères, Laboratoire de Neurobiologie des Réseaux Sensorimoteurs, UMR 7060 CNRS, Equipe Biologie du Développement et de la Différenciation Neuromusculaire, Paris Cedex, France
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36
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Rana OR, Zobel C, Saygili E, Brixius K, Gramley F, Schimpf T, Mischke K, Frechen D, Knackstedt C, Schwinger RHG, Schauerte P, Saygili E. A simple device to apply equibiaxial strain to cells cultured on flexible membranes. Am J Physiol Heart Circ Physiol 2007; 294:H532-40. [PMID: 17965285 DOI: 10.1152/ajpheart.00649.2007] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The biomechanical environment to which cells are exposed is important to their normal growth, development, interaction, and function. Accordingly, there has been much interest in studying the role of biomechanical forces in cell biology and pathophysiology. This has led to the introduction and even commercialization of many experimental devices. Many of the early devices were limited by the heterogeneity of deformation of cells cultivated in different locations of the culture plate membranes and were also attached with complicated technical/electronic efforts resulting in a restriction of the reproducibility of these devices. The objective of this study was to design and build a simple device to allow the application of dose-dependent homogeneous equibiaxial static stretch to cells cultured on flexible silicone membranes to investigate biological and biomedical questions. In addition, cultured neonatal rat atrial cardiomyocytes were stretched with the proposed device with different strain gradients. For the first time with this study we could demonstrate that stretch up to 21% caused dose-dependent changes in biological markers such as the calcineurin activity, modulatory calcineurin-interacting protein-1, voltage-gated potassium channel isoform 4.2, and voltage-gated K(+) channel-interacting proteins-2 gene expression and transient outward potassium current densities but not the protein-to-DNA ratio and atrial natriuretic peptide mRNA. With both markers mentioned last, dose-dependent stretch alterations could only be achieved with stretch up to 13%. The simple and low-cost device presented here might be applied to a wide range of experimental settings in different fields of research.
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Affiliation(s)
- Obaida R Rana
- Univ. Hospital RWTH Aachen, Dept. I of Internal Medicine, Division of Cardiology, Pulmonary and Vascular Diseases, Pauwelsstrasse 30, Aachen, Germany.
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37
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Hand BD, Kostek MC, Ferrell RE, Delmonico MJ, Douglass LW, Roth SM, Hagberg JM, Hurley BF. Influence of promoter region variants of insulin-like growth factor pathway genes on the strength-training response of muscle phenotypes in older adults. J Appl Physiol (1985) 2007; 103:1678-87. [PMID: 17761791 PMCID: PMC2811278 DOI: 10.1152/japplphysiol.00420.2007] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
To examine the influence of insulin-like growth factor (IGF) pathway gene polymorphisms on muscle mass and strength responses to strength training (ST), we studied 128 White and Black men and women before and after a 10-wk single-leg knee extension ST program. One-repetition maximum strength, muscle volume (MV) via computed tomography, and muscle quality (MQ) were assessed at baseline and after 10 wk of ST. There was a significant combined IGF1 cytosine adenine (CA) repeat gene effect, which included both the IGF1 CA repeat main effect and IGF1 CA repeat x PPP3R1 insertion-deletion (I/D) gene x gene interaction effect, on the changes in strength (P < 0.01) and MQ (P < 0.05) with ST. There was a trend for a significant gene x gene interaction between IGF1 CA repeat and PPP3R1 I/D for changes in strength (P = 0.07) and MQ (P = 0.06) with ST. The influence of the PPP3R1 A-202C gene polymorphism on change in MV with ST approached significance (P = 0.06). The IGF1 CA repeat polymorphism had a significant influence on the change in strength and MV combined with ST (P < 0.05), whereas the influence of the PPP3R1 I/D polymorphism approached significance (P = 0.08). There were no associations between the IGFBP3 A-202C gene polymorphism and the muscle phenotypic responses to ST. These data suggest that two of the three IGF pathway gene polymorphisms identified in this study influence muscle phenotypic responses to ST in both black and white older men and women.
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Affiliation(s)
- Brian D Hand
- Dept. of Kinesiology, Univ. of Maryland, College Park, MD 20742, USA
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38
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Coffey VG, Hawley JA. The molecular bases of training adaptation. SPORTS MEDICINE (AUCKLAND, N.Z.) 2007. [PMID: 17722947 DOI: 10.2165/00007256-200737090-00001.] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Skeletal muscle is a malleable tissue capable of altering the type and amount of protein in response to disruptions to cellular homeostasis. The process of exercise-induced adaptation in skeletal muscle involves a multitude of signalling mechanisms initiating replication of specific DNA genetic sequences, enabling subsequent translation of the genetic message and ultimately generating a series of amino acids that form new proteins. The functional consequences of these adaptations are determined by training volume, intensity and frequency, and the half-life of the protein. Moreover, many features of the training adaptation are specific to the type of stimulus, such as the mode of exercise. Prolonged endurance training elicits a variety of metabolic and morphological changes, including mitochondrial biogenesis, fast-to-slow fibre-type transformation and substrate metabolism. In contrast, heavy resistance exercise stimulates synthesis of contractile proteins responsible for muscle hypertrophy and increases in maximal contractile force output. Concomitant with the vastly different functional outcomes induced by these diverse exercise modes, the genetic and molecular mechanisms of adaptation are distinct. With recent advances in technology, it is now possible to study the effects of various training interventions on a variety of signalling proteins and early-response genes in skeletal muscle. Although it cannot presently be claimed that such scientific endeavours have influenced the training practices of elite athletes, these new and exciting technologies have provided insight into how current training techniques result in specific muscular adaptations, and may ultimately provide clues for future and novel training methodologies. Greater knowledge of the mechanisms and interaction of exercise-induced adaptive pathways in skeletal muscle is important for our understanding of the aetiology of disease, maintenance of metabolic and functional capacity with aging, and training for athletic performance. This article highlights the effects of exercise on molecular and genetic mechanisms of training adaptation in skeletal muscle.
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Affiliation(s)
- Vernon G Coffey
- School of Medical Sciences, Exercise Metabolism Group, RMIT University, Melbourne, Victoria, Australia
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39
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Stupka N, Schertzer JD, Bassel-Duby R, Olson EN, Lynch GS. Calcineurin-A alpha activation enhances the structure and function of regenerating muscles after myotoxic injury. Am J Physiol Regul Integr Comp Physiol 2007; 293:R686-94. [PMID: 17475677 DOI: 10.1152/ajpregu.00612.2006] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Calcineurin signaling is essential for successful muscle regeneration. Although calcineurin inhibition compromises muscle repair, it is not known whether calcineurin activation can enhance muscle repair after injury. Tibialis anterior (TA) muscles from adult wild-type (WT) and transgenic mice overexpressing the constitutively active calcineurin-A alpha transgene under the control of the mitochondrial creatine kinase promoter (MCK-CnA alpha*) were injected with the myotoxic snake venom Notexin to destroy all muscle fibers. The TA muscle of the contralateral limb served as the uninjured control. Muscle structure was assessed at 5 and 9 days postinjury, and muscle function was tested in situ at 9 days postinjury. Calcineurin stimulation enhanced muscle regeneration and altered levels of myoregulatory factors (MRFs). Recovery of myofiber size and force-producing capacity was hastened in injured muscles of MCK-CnA alpha* mice compared with control. Myogenin levels were greater 5 days postinjury and myocyte enhancer factor 2a (MEF2a) expression was greater 9 days postinjury in muscles of MCK-CnA alpha* mice compared with WT mice. Higher MEF2a expression in regenerating muscles of MCK-CnA alpha* mice 9 days postinjury may be related to an increase of slow fiber genes. Calcineurin activation in uninjured and injured TA muscles slowed muscle contractile properties, reduced fatigability, and enhanced force recovery after 4 min of intermittent maximal stimulation. Therefore, calcineurin activation can confer structural and functional benefits to regenerating skeletal muscles, which may be mediated in part by differential expression of MRFs.
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Affiliation(s)
- Nicole Stupka
- Basic and Clinical Myology Laboratory, Department of Physiology, The University of Melbourne, Victoria, Australia
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40
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Abstract
Recruitment determines the profile of fibre-type-specific genes expressed across the range of muscle fibres associated with slow, fast fatigue-resistant and fast fatiguable motor units. Downstream signalling pathways activated by neural signalling and mechanical load have been the focus of intensive research in past years. It is now known that Ca2+-dependent calcineurin–nuclear factor of activated T cells and insulin-like growth factor 1 pathways and their downstream mediators contribute to these adaptive responses. These pathways regulate gene expression through muscle-specific (myocyte-enhancing factor 2, myoblast determination protein) and non-specific (nuclear factor of activated T cell 2, GATA-2) transcription factors. Transcriptional signals activated with increased contractile activity result in altered expression of fibre-type specific genes, including the myosin heavy chain isoforms and oxidative and glycolytic enzymes and a net change in muscle fibre-type composition. In contrast, transcriptional signals activated by increased load bearing result in hypertrophy or a growth response, a component of which involves satellite cell recruitment and fusion with existing adult myofibres. Calcineurin has been identified as a key mediator in the hypertrophic response, and the current challenge has been to determine the downstream target genes of this pathway. Exciting new data have emerged, showing that myostatin, a negative regulator of muscle growth, and utrophin, a cytoskeletal protein important in maintaining membrane integrity, are downstream targets of calcineurin signalling. Increased understanding of these mediators of muscle growth may provide strategies for the development of effective therapeutics to counter muscle weakness and muscular dystrophy.
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Affiliation(s)
- Robin N Michel
- Neuromuscular Research Laboratory, Department of Chemistry and Biochemistry, Laurentian University, Sudbury, Ontario P3E 2C6, Canada.
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41
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Launay T, Noirez P, Butler-Browne G, Agbulut O. Expression of slow myosin heavy chain during muscle regeneration is not always dependent on muscle innervation and calcineurin phosphatase activity. Am J Physiol Regul Integr Comp Physiol 2006; 290:R1508-14. [PMID: 16424085 DOI: 10.1152/ajpregu.00486.2005] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
In the literature, there is an ambiguity as to the respective roles played by calcineurin phosphatase activity (CPA) and muscle innervation in the reestablishment of the slow-twitch muscle phenotype after muscle regeneration in different species. In this study, we wanted to determine the role of calcineurin and muscle innervation on the appearance and maintenance of the slow phenotype during mouse muscle regeneration. The pattern of myosin expression and CPA was analyzed in adult ( n = 15), regenerating ( n = 45) and denervated-regenerating ( n = 32) slow-twitch soleus and fast-twitch extensor digitorum longus (EDL) muscles. Moreover, in a second group of denervated-regenerating mice ( n = 9), the animals were treated with a calcineurin inhibitor. Regeneration was induced by injection of cardiotoxin and in the denervated-regenerating group, denervation was carried out by cutting the sciatic nerve before the administration of cardiotoxin. In innervated-regenerating soleus muscle, CPA increased continuously after 10 days postinjury and by 21 days, there was a 3.5-fold increase in CPA compared with adult basal level, whereas in innervated-regenerating EDL muscle, CPA remained unchanged. Moreover, our results show that in denervated-regenerating muscles, the MyHC profile was identical in spite of the functional differences inherent in these muscles. In long-term denervated-regenerating muscles, a slow muscle phenotype was reexpressed both in the presence or absence of calcineurin inhibitor. Our results show that although in innervated-regenerating mouse muscle, the appearance of a slow phenotype is correlated with a peak of CPA, in denervated-regenerating muscles, a slow phenotype is triggered and maintained in a calcineurin- and nerve-independent manner.
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Affiliation(s)
- Thierry Launay
- University Paris 7, Institut National de la Santé et de la Recherce Médicale, Paris, France
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Zbreski MG, Helwig BG, Mitchell KE, Musch TI, Weiss ML, McAllister RM. Effects of Cyclosporine-A on Rat Soleus Muscle Fiber Size and Phenotype. Med Sci Sports Exerc 2006; 38:833-9. [PMID: 16672834 DOI: 10.1249/01.mss.0000218119.67120.b9] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
PURPOSE Organ transplant patients treated with cyclosporine-A (CsA) often exhibit weight loss and muscle weakness. The cellular target of CsA, calcineurin, has been implicated in maintenance of muscle fiber size and in expression of the type I skeletal muscle phenotype. We hypothesized that CsA treatment would cause fiber atrophy, as well as increase type IIa myosin heavy chain (MHC) content and oxidative enzyme activities in the soleus muscle. METHODS Rats were treated with CsA for 21 d (20 mg.kg(-1).d(-1); N = 16) and compared with control rats given olive oil vehicle (Veh; N = 16). Soleus muscles were excised bilaterally. MHC content was determined by gel electrophoresis, oxidative enzyme activities by spectrophotometric methods, and fiber type and size by histochemistry. RESULTS Lymphocyte count was depressed in CsA rats (P < 0.05), indicating treatment efficacy. Type IIa MHC content was increased in the soleus muscle with CsA (Veh, 10.4 +/- 1.7%; CsA, 15.1 +/- 2.0; P < 0.05) at the expense of type I MHC. Soleus muscle oxidative enzyme activities were also increased with CsA treatment (P < 0.05). Soleus muscle atrophy occurred, reflected by a 22% decrease in fiber cross-sectional area (Veh, 3255 +/- 105 microm(2); CsA, 2533 +/- 125; P < 0.05). CONCLUSION These findings indicate that CsA treatment is associated with changes in skeletal muscle fiber size and phenotype. The former may underlie clinical symptoms of transplant patients treated with CsA.
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Affiliation(s)
- Mike G Zbreski
- Department of Anatomy and Physiology, Kansas State University, Manhattan, USA
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Stupka N, Michell BJ, Kemp BE, Lynch GS. Differential calcineurin signalling activity and regeneration efficacy in diaphragm and limb muscles of dystrophic mdx mice. Neuromuscul Disord 2006; 16:337-46. [PMID: 16621557 DOI: 10.1016/j.nmd.2006.03.003] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2005] [Revised: 02/07/2006] [Accepted: 03/03/2006] [Indexed: 11/30/2022]
Abstract
Calcineurin activity is essential for successful skeletal muscle regeneration in young mdx mice and in wild type mice following myotoxic injury and cryodamage. In mature myofibres of adult mdx mice, calcineurin stimulation can ameliorate the dystrophic pathology. The aim of this study was to test the hypothesis that the more severe dystrophic pathology of the diaphragm compared with hindlimb muscles of mdx mice could be attributed to aberrant calcineurin signalling and that due to ongoing regeneration calcineurin activity would be greater in muscles of adult mdx than wild type mice. Differences in markers of regeneration between tibialis anterior and diaphragm muscles were also characterised, to determine whether there was an association between regeneration efficacy and calcineurin activity in dystrophic muscles. In diaphragm muscles of adult mdx mice, the proportion of centrally nucleated fibres and developmental myosin heavy chain protein expression was lower and myogenin protein expression was higher than in tibialis anterior muscles. Calcineurin and activated NFATc1 protein content and calcineurin phosphatase activity were higher in muscles from mdx than wild type mice and calcineurin activation was greater in diaphragm than tibialis anterior muscles of mdx mice. Thus, despite greater calcineurin activity in diaphragm compared to hindlimb muscles, regeneration events downstream of myoblast differentiation and mediated by the injured myofibre were severely compromised.
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MESH Headings
- Animals
- Calcineurin/metabolism
- Cell Differentiation/genetics
- Diaphragm/metabolism
- Diaphragm/pathology
- Diaphragm/physiopathology
- Disease Models, Animal
- Extremities/physiopathology
- Mice
- Mice, Inbred mdx
- Muscle Fibers, Skeletal/metabolism
- Muscle Fibers, Skeletal/pathology
- Muscle, Skeletal/metabolism
- Muscle, Skeletal/pathology
- Muscle, Skeletal/physiopathology
- Muscular Dystrophy, Duchenne/genetics
- Muscular Dystrophy, Duchenne/metabolism
- Muscular Dystrophy, Duchenne/physiopathology
- Myogenin/metabolism
- Myosin Heavy Chains/metabolism
- NFATC Transcription Factors/metabolism
- Regeneration/genetics
- Signal Transduction/genetics
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Affiliation(s)
- Nicole Stupka
- Department of Physiology, The University of Melbourne, Grattan Street, Melbourne, Vic. 3010, Australia
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44
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Chakkalakal JV, Michel SA, Chin ER, Michel RN, Jasmin BJ. Targeted inhibition of Ca2+/calmodulin signaling exacerbates the dystrophic phenotype in mdx mouse muscle. Hum Mol Genet 2006; 15:1423-35. [PMID: 16551657 DOI: 10.1093/hmg/ddl065] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
In this study, we crossbred mdx mice with transgenic mice expressing a small peptide inhibitor for calmodulin (CaM), known as the CaM-binding protein (CaMBP), driven by the slow fiber-specific troponin I slow promoter. This strategy allowed us to determine the impact of interfering with Ca(2+)/CaM-based signaling in dystrophin-deficient slow myofibers. Consistent with impairments in the Ca(2+)/CaM-regulated enzymes calcineurin and Ca(2+)/CaM-dependent kinase, the nuclear accumulation of nuclear factor of activated T-cell c1 and myocyte enhancer factor 2C was reduced in slow fibers from mdx/CaMBP mice. We also detected significant reductions in the levels of peroxisome proliferator gamma co-activator 1alpha and GA-binding protein alpha mRNAs in slow fiber-rich soleus muscles of mdx/CaMBP mice. In parallel, we observed significantly lower expression of myosin heavy chain I mRNA in mdx/CaMBP soleus muscles. This correlated with fiber-type shifts towards a faster phenotype. Examination of mdx/CaMBP slow muscle fibers revealed significant reductions in A-utrophin, a therapeutically relevant protein that can compensate for the lack of dystrophin in skeletal muscle. In accordance with lower levels of A-utrophin, we noted a clear exacerbation of the dystrophic phenotype in mdx/CaMBP slow fibers as exemplified by several pathological indices. These results firmly establish Ca(2+)/CaM-based signaling as key to regulating expression of A-utrophin in muscle. Furthermore, this study illustrates the therapeutic potential of using targets of Ca(2+)/CaM-based signaling as a strategy for treating Duchenne muscular dystrophy (DMD). Finally, our results further support the concept that strategies aimed at promoting the slow oxidative myofiber program in muscle may be effective in altering the relentless progression of DMD.
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Affiliation(s)
- Joe V Chakkalakal
- Department of Cellular and Molecular Medicine, Centre for Neuromuscular Diseases, Faculty of Medicine, University of Ottawa, Ottawa, Ont., Canada K1H 8M5
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Arai C, Ohnuki Y, Umeki D, Hirashita A, Saeki Y. Effects of Clenbuterol and Cyclosporin A on the Myosin Heavy Chain mRNA Level and the Muscle Mass in Rat Masseter. J Physiol Sci 2006; 56:205-9. [PMID: 16839454 DOI: 10.2170/physiolsci.rp002206] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2006] [Accepted: 05/22/2006] [Indexed: 11/05/2022]
Abstract
To gain more insight into the molecular mechanism of muscle growth and fiber-type transformations, we analyzed the effects of beta(2)-adrenergic agonist clenbuterol (CB) and/or cyclosporin A (CsA), a potent inhibitor of calcineurin (CaN), on the muscle mass as well as on the mRNA levels of myosin heavy chains (MHC I, IIa, IId/x, IIb), using a real-time RT-PCR with specific primers in rat masseter. In comparison with control, the CB treatment significantly decreased the MHC I mRNA level (p < 0.01), but increased the MHC IId/x mRNA level (p < 0.01), and the CsA treatment significantly decreased the MHC I mRNA level (p < 0.05) in association with the significant decrease in MHC IIb mRNA level (p < 0.05). The CB+CsA treatment significantly decreased the levels of MHC I (p < 0.01) and IIa mRNAs (p < 0.05), but increased the MHC IId/x mRNA level (p < 0.001) in association with a significant decrease in MHC IIb mRNA level (p < 0.01), in comparison with control. The masseter muscle mass was significantly (p < 0.001) increased by either the CB or the CB + CsA treatment, but decreased with the CsA treatment (p < 0.01). These results suggest that in rat masseter muscle, CB has an anabolic action accompanying MHC mRNA I IIa IId/x sequence transition independently of CaN-signaling pathways, and CaN is involved in the type I fiber gene expression and the muscle mass maintenance of type IIb fiber.
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Affiliation(s)
- Chihiro Arai
- Department of Orthodontics, Tsurumi University School of Dental Medicine, 2-1-3 Tsurumi, Tsurumi-ku, Yokohama 230-8501, Japan
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46
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Angus LM, Chakkalakal JV, Méjat A, Eibl JK, Bélanger G, Megeney LA, Chin ER, Schaeffer L, Michel RN, Jasmin BJ. Calcineurin-NFAT signaling, together with GABP and peroxisome PGC-1α, drives utrophin gene expression at the neuromuscular junction. Am J Physiol Cell Physiol 2005; 289:C908-17. [PMID: 15930144 DOI: 10.1152/ajpcell.00196.2005] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
We examined whether calcineurin-NFAT (nuclear factors of activated T cells) signaling plays a role in specifically directing the expression of utrophin in the synaptic compartment of muscle fibers. Immunofluorescence experiments revealed the accumulation of components of the calcineurin-NFAT signaling cascade within the postsynaptic membrane domain of the neuromuscular junction. RT-PCR analysis using synaptic vs. extrasynaptic regions of muscle fibers confirmed these findings by showing an accumulation of calcineurin transcripts within the synaptic compartment. We also examined the effect of calcineurin on utrophin gene expression. Pharmacological inhibition of calcineurin in mice with either cyclosporin A or FK506 resulted in a marked decrease in utrophin A expression at synaptic sites, whereas constitutive activation of calcineurin had the opposite effect. Mutation of the previously identified NFAT binding site in the utrophin A promoter region, followed by direct gene transfer studies in mouse muscle, led to an inhibition in the synaptic expression of a lacZ reporter gene construct. Transfection assays performed with cultured myogenic cells indicated that calcineurin acted additively with GA binding protein (GABP) to transactivate utrophin A gene expression. Because both GABP- and calcineurin-mediated pathways are targeted by peroxisome proliferator-activated receptor-γ coactivator-1α (PGC-1α), we examined whether this coactivator contributes to utrophin gene expression. In vitro and in vivo transfection experiments showed that PGC-1α alone induces transcription from the utrophin A promoter. Interestingly, this induction is largely potentiated by coexpression of PGC-1α with GABP. Together, these studies indicate that the synaptic expression of utrophin is also driven by calcineurin-NFAT signaling and occurs in conjunction with signaling events that involve GABP and PGC-1α.
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Affiliation(s)
- Lindsay M Angus
- Department of Cellular and Molecular Medicine, and Centre for Neuromuscular Disease, Faculty of Medicine, University of Ottawa, 451 Smyth Road, Ottawa, Ontario, Canada K1H 8M5
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Oh M, Rybkin II, Copeland V, Czubryt MP, Shelton JM, van Rooij E, Richardson JA, Hill JA, De Windt LJ, Bassel-Duby R, Olson EN, Rothermel BA. Calcineurin is necessary for the maintenance but not embryonic development of slow muscle fibers. Mol Cell Biol 2005; 25:6629-38. [PMID: 16024798 PMCID: PMC1190329 DOI: 10.1128/mcb.25.15.6629-6638.2005] [Citation(s) in RCA: 81] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
Skeletal muscles are a mosaic of slow and fast twitch myofibers. During embryogenesis, patterns of fiber type composition are initiated that change postnatally to meet physiological demand. To examine the role of the protein phosphatase calcineurin in the initiation and maintenance of muscle fiber types, we used a "Flox-ON" approach to obtain muscle-specific overexpression of the modulatory calcineurin-interacting protein 1 (MCIP1/DSCR1), an inhibitor of calcineurin. Myo-Cre transgenic mice with early skeletal muscle-specific expression of Cre recombinase were used to activate the Flox-MCIP1 transgene. Contractile components unique to type 1 slow fibers were absent from skeletal muscle of adult Myo-Cre/Flox-MCIP1 mice, whereas oxidative capacity, myoglobin content, and mitochondrial abundance were unaltered. The soleus muscles of Myo-Cre/Flox-MCIP1 mice fatigued more rapidly than the wild type as a consequence of the replacement of the slow myosin heavy chain MyHC-1 with a fast isoform, MyHC-2A. MyHC-1 expression in Myo-Cre/Flox-MCIP1 embryos and early neonates was normal. These results demonstrate that developmental patterning of slow fibers is independent of calcineurin, while the maintenance of the slow-fiber phenotype in the adult requires calcineurin activity.
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Affiliation(s)
- Misook Oh
- University of Texas Southwestern Medical Center, 5323 Harry Hines Blvd., Dallas, TX 75390, USA
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Sakuma K, Nakao R, Aoi W, Inashima S, Fujikawa T, Hirata M, Sano M, Yasuhara M. Cyclosporin A treatment upregulates Id1 and Smad3 expression and delays skeletal muscle regeneration. Acta Neuropathol 2005; 110:269-80. [PMID: 15986223 DOI: 10.1007/s00401-005-1049-x] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2004] [Revised: 04/05/2005] [Accepted: 04/06/2005] [Indexed: 10/25/2022]
Abstract
The molecular signaling pathway linked to muscle regeneration has not yet been identified. Previously, we demonstrated that mice treated with cyclosporin A (CsA), a calcineurin inhibitor, failed to regenerate normally after muscle damage. Using reverse transcription (RT)-PCR, Western blot and immunohistochemical analysis, we investigated whether the amounts of nuclear factor of activated T cells (NFAT), myocyte-enhancer factor 2 (MEF2), the MyoD family, Id-1, and Smad3 change in the regenerating muscle after CsA treatment. Adult male ICR mice were subjected to a bupivacaine injection into the tibialis anterior muscle, and were treated with either CsA (25 mg/kg) or vehicle once daily. They were killed at 1, 2, 4, 6, 9 and 14 days post injury. RT-PCR analysis did not show a significant difference in MEF2s, MyoD and myogenin mRNA levels in the regenerating muscle in either placebo- and CsA-administered mice. In contrast, a significant increase in MRF4 mRNA was seen in CsA-administered mice compared to the placebo-treated mice at 4 and 9 days post surgery. In CsA-treated mice, the level of Id1 mRNA was elevated at day 9 relative to the placebo-treated mice. After 6 days, the CsA-treated mice possessed more abundant proliferating cell nuclear antigen (PCNA) and cyclin D1 protein in many satellite cells and/or myoblast-like cells in the regenerating muscle. The amount of myostatin, TGF-beta2 and Smad3 mRNA and proteins was increased more markedly in the mice treated with CsA. After 9 days, many satellite cells and/or myoblasts showed apparent co-localization of both MyoD and Smad3 in CsA-, but not in placebo-, treated mice. Our results demonstrated that CsA treatment upregulates Id1 and Smad3 expression and delays skeletal muscle regeneration in vivo.
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Affiliation(s)
- Kunihiro Sakuma
- Department of Legal Medicine, Kyoto Prefectural University of Medicine, 465 Kajii-cho, Kawaramachi-hirokoji, Kamigyo-ku, 602-8566 Kyoto, Japan.
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Armand AS, Pariset C, Laziz I, Launay T, Fiore F, Della Gaspera B, Birnbaum D, Charbonnier F, Chanoine C. FGF6 regulates muscle differentiation through a calcineurin-dependent pathway in regenerating soleus of adult mice. J Cell Physiol 2005; 204:297-308. [PMID: 15672378 DOI: 10.1002/jcp.20302] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Important functions in myogenesis have been proposed for FGF6, a member of the fibroblast growth factor family accumulating almost exclusively in the myogenic lineage, but its precise role in vivo remains mostly unclear. Here, using FGF6 (-/-) mice and rescue experiments by injection of recombinant FGF6, we dissected the functional role of FGF6 during in vivo myogenesis. We found that the appearance of myotubes was accelerated during regeneration of the soleus of FGF6 (-/-) mice versus wild type mice. This accelerated differentiation was correlated with increased expression of differentiation markers such as CdkIs and calcineurin, as well as structural markers such as MHCI and slow TnI. We showed that an elevated transcript level for calcineurin Aalpha subunit correlated with a positive regulation of calcineurin A activity in regenerating soleus of the FGF6 (-/-) mice. Cyclin D1 and calcineurin were up- and down-regulated, respectively in a dose-dependent manner upon injection of rhFGF6 in regenerating soleus of the mutant mice. We showed an increase of the number of slow oxidative (type I) myofibers, whereas fast oxidative (type IIa) myofibers were decreased in number in regenerating soleus of FGF6 (-/-) mice versus that of wild type mice. In adult soleus, the number of type I myofibers was also higher in FGF6 (-/-) mice than in wild type mice. Taken together these results evidenced a specific phenotype for soleus of the FGF6 (-/-) mice and led us to propose a model accounting for a specific dose-dependent effect of FGF6 in muscle regeneration. At high doses, FGF6 stimulates the proliferation of the myogenic stem cells, whereas at lower doses it regulates both muscle differentiation and muscle phenotype via a calcineurin-signaling pathway.
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Affiliation(s)
- Anne-Sophie Armand
- UMR 7060 CNRS, Equipe Biologie du Développement et de la Différenciation Neuromusculaire, Centre Universitaire des Saints-Pères, Université René Descartes, Paris, France
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Oishi Y, Ogata T, Ohira Y, Taniguchi K, Roy RR. Calcineurin and heat shock protein 72 in functionally overloaded rat plantaris muscle. Biochem Biophys Res Commun 2005; 330:706-13. [PMID: 15809055 DOI: 10.1016/j.bbrc.2005.03.049] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2005] [Indexed: 01/14/2023]
Abstract
The involvement of calcineurin (CaN) and heat shock protein (Hsp) 72 in the regulation of fiber size and/or phenotype in response to functional overload (FO) was investigated. In one FO group, the plantaris muscle was overloaded by cutting the distal tendons (5-10 mm length) of the soleus and gastrocnemius of 3-week-old male Wistar rats. Cyclosporin A (CsA), a CaN inhibitor, was injected daily (5 mg/kg body weight, i.p.) in a second group of FO rats (FO+CsA group) for a 2-week period. Compared to age-matched controls (Con), the absolute and relative plantaris weights were increased in both FO groups: the hypertrophic response was attenuated in FO+CsA rats. The mean cross-sectional area of each fiber type was increased (approximately 2.0-fold) in the plantaris of FO rats: CsA treatment attenuated this effect, although the fibers were still larger than in Con rats. The percent composition of myosin heavy chain (MHC) IIb decreased from 54% in Con to 19% in FO rats, whereas types I, IIa, and IIx MHC increased in the FO rats. CsA treatment blunted the shifts in MHC isoforms: the FO+CsA group showed a smaller decrease in type IIb and a smaller increase in type IIx MHC than the FO group. The levels of CaN-A and -B proteins were higher (approximately 2.5-fold) in FO than Con rats, whereas these values were similar in Con and FO+CsA rats. Hsp72 protein levels were higher in FO (3.6-fold) and FO+CsA (5.2-fold) than Con rats, with the values being significantly higher in the FO+CsA than FO rats. CsA treatment in Con rats had no effects on muscle mass, fiber size, MHC composition, and Hsp72 or CaN levels. Combined, these results suggest that CaN levels are related to changes in both fiber size and phenotype, and that Hsp72 levels are more related to the levels of stress added to the muscle rather than to increases in the slow fiber phenotype in functionally overloaded rat plantaris muscles.
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MESH Headings
- Animals
- Calcineurin/metabolism
- Cyclosporine/pharmacology
- HSP72 Heat-Shock Proteins
- Heat-Shock Proteins/metabolism
- Male
- Muscle Fibers, Fast-Twitch/drug effects
- Muscle Fibers, Fast-Twitch/pathology
- Muscle Fibers, Fast-Twitch/physiology
- Muscle Fibers, Slow-Twitch/drug effects
- Muscle Fibers, Slow-Twitch/pathology
- Muscle Fibers, Slow-Twitch/physiology
- Muscle, Skeletal/drug effects
- Muscle, Skeletal/pathology
- Muscle, Skeletal/physiology
- Myosin Heavy Chains/metabolism
- Organ Size/drug effects
- Protein Isoforms/metabolism
- Rats
- Rats, Wistar
- Time Factors
- Up-Regulation/drug effects
- Weight-Bearing/physiology
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Affiliation(s)
- Yasuharu Oishi
- Laboratory of Muscle Physiology, Faculty of Education, Kumamoto University, Kumamoto 860-8555, Japan.
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