1
|
Millward DJ. Post-natal muscle growth and protein turnover: a narrative review of current understanding. Nutr Res Rev 2024; 37:141-168. [PMID: 37395180 DOI: 10.1017/s0954422423000124] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/04/2023]
Abstract
A model explaining the dietary-protein-driven post-natal skeletal muscle growth and protein turnover in the rat is updated, and the mechanisms involved are described, in this narrative review. Dietary protein controls both bone length and muscle growth, which are interrelated through mechanotransduction mechanisms with muscle growth induced both from stretching subsequent to bone length growth and from internal work against gravity. This induces satellite cell activation, myogenesis and remodelling of the extracellular matrix, establishing a growth capacity for myofibre length and cross-sectional area. Protein deposition within this capacity is enabled by adequate dietary protein and other key nutrients. After briefly reviewing the experimental animal origins of the growth model, key concepts and processes important for growth are reviewed. These include the growth in number and size of the myonuclear domain, satellite cell activity during post-natal development and the autocrine/paracrine action of IGF-1. Regulatory and signalling pathways reviewed include developmental mechanotransduction, signalling through the insulin/IGF-1-PI3K-Akt and the Ras-MAPK pathways in the myofibre and during mechanotransduction of satellite cells. Likely pathways activated by maximal-intensity muscle contractions are highlighted and the regulation of the capacity for protein synthesis in terms of ribosome assembly and the translational regulation of 5-TOPmRNA classes by mTORC1 and LARP1 are discussed. Evidence for and potential mechanisms by which volume limitation of muscle growth can occur which would limit protein deposition within the myofibre are reviewed. An understanding of how muscle growth is achieved allows better nutritional management of its growth in health and disease.
Collapse
Affiliation(s)
- D Joe Millward
- Department of Nutritional Sciences, School of Biosciences & Medicine, Faculty of Health and Medical Sciences, University of Surrey, Guildford, UK
| |
Collapse
|
2
|
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.
Collapse
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
| |
Collapse
|
3
|
Viggars MR, Wen Y, Peterson CA, Jarvis JC. Automated cross-sectional analysis of trained, severely atrophied and recovering rat skeletal muscles using MyoVision 2.0. J Appl Physiol (1985) 2022; 132:593-610. [PMID: 35050795 DOI: 10.1152/japplphysiol.00491.2021] [Citation(s) in RCA: 21] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The number of myonuclei within a muscle fiber is an important factor in muscle growth, but its regulation during muscle adaptation is not well understood. We aimed to elucidate the timecourse of myonuclear dynamics during endurance training, loaded and concentric resistance training, and nerve silencing-induced disuse atrophy with subsequent recovery. We modified tibialis anterior muscle activity in free-living rats with electrical stimulation from implantable pulse generators, or with implantable osmotic pumps delivering tetrodotoxin (TTX) to silence the motor nerve without transection. We used the updated, automated software MyoVision to measure fiber type-specific responses in whole tibialis anterior cross-sections (~8000 fibers each). Seven days of continuous low frequency stimulation (CLFS) reduced muscle mass (-12%), increased slower myosin isoforms and reduced IIX/IIB fibers (-32%) and substantially increased myonuclei especially in IIX/IIB fibers (55.5%). High load resistance training (Spillover), produced greater hypertrophy (~16%) in muscle mass and fiber cross-sectional area (CSA) than low load resistance training (concentric, ~6%) and was associated with myonuclear addition in all fiber types (35-46%). TTX-induced nerve silencing resulted in progressive loss in muscle mass, fiber CSA, and myonuclei per fiber cross-section (-50.7%, -53.7%, -40.7%, respectively at 14 days). Myonuclear loss occurred in a fiber type-independent manner, but subsequent recovery during voluntary habitual activity suggested that type IIX/IIB fibers contained more new myonuclei during recovery from severe atrophy. This study demonstrates the power and accuracy provided by the updated MyoVision software and introduces new models for studying myonuclear dynamics in training, detraining, retraining, repeated disuse, and recovery.
Collapse
Affiliation(s)
- Mark Robert Viggars
- Research Institute for Sport & Exercise Sciences, grid.4425.7Liverpool John Moores University, Liverpool, United Kingdom.,Department of Physiology and Functional Genomics, University of Florida, Gainesville, Florida, United States.,Myology Institute, University of Florida, Gainesville, Florida, United States
| | - Yuan Wen
- Department of Physiology, College of Medicine, University of Kentucky, Lexington, Kentucky, United States.,Center for Muscle Biology, University of Kentucky, Lexington, Kentucky, United States.,MyoAnalytics, LLC, Lexington, Kentucky, United States
| | - Charlotte A Peterson
- Department of Physiology, College of Medicine, University of Kentucky, Lexington, Kentucky, United States.,Center for Muscle Biology, University of Kentucky, Lexington, Kentucky, United States
| | - Jonathan C Jarvis
- Research Institute for Sport & Exercise Sciences, grid.4425.7Liverpool John Moores University, Liverpool, United Kingdom
| |
Collapse
|
4
|
Hettinger ZR, Hamagata K, Confides AL, Lawrence MM, Miller BF, Butterfield TA, Dupont-Versteegden EE. Age-Related Susceptibility to Muscle Damage Following Mechanotherapy in Rats Recovering From Disuse Atrophy. J Gerontol A Biol Sci Med Sci 2021; 76:2132-2140. [PMID: 34181006 PMCID: PMC8599051 DOI: 10.1093/gerona/glab186] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2021] [Indexed: 12/13/2022] Open
Abstract
The inability to fully recover lost muscle mass following periods of disuse atrophy predisposes older adults to lost independence and poor quality of life. We have previously shown that mechanotherapy at a moderate load (4.5 N) enhances muscle mass recovery following atrophy in adult, but not older adult rats. We propose that elevated transverse stiffness in aged muscle inhibits the growth response to mechanotherapy and hypothesize that a higher load (7.6 N) will overcome this resistance to mechanical stimuli. F344/BN adult and older adult male rats underwent 14 days of hindlimb suspension, followed by 7 days of recovery with (RE + M) or without (RE) mechanotherapy at 7.6 N on gastrocnemius muscle. The 7.6 N load was determined by measuring transverse passive stiffness and linearly scaling up from 4.5 N. No differences in protein turnover or mean fiber cross-sectional area were observed between RE and RE + M for older adult rats or adult rats at 7.6 N. However, there was a higher number of small muscle fibers present in older adult, but not adult rats, which was explained by a 16-fold increase in the frequency of small fibers expressing embryonic myosin heavy chain. Elevated central nucleation, satellite cell abundance, and dystrophin-/laminin+ fibers were present in older adult rats only following 7.6 N, while 4.5 N did not induce damage at either age. We conclude that age is an important variable when considering load used during mechanotherapy and age-related transverse stiffness may predispose older adults to damage during the recovery period following disuse atrophy.
Collapse
Affiliation(s)
- Zachary R Hettinger
- Department of Physical Therapy, College of Health Sciences, University of Kentucky, Lexington, USA
- Center for Muscle Biology, University of Kentucky, Lexington, USA
| | - Kyoko Hamagata
- Center for Muscle Biology, University of Kentucky, Lexington, USA
| | - Amy L Confides
- Department of Physical Therapy, College of Health Sciences, University of Kentucky, Lexington, USA
- Center for Muscle Biology, University of Kentucky, Lexington, USA
| | - Marcus M Lawrence
- Aging and Metabolism Research Program, Oklahoma Medical Research Foundation, Oklahoma City, USA
| | - Benjamin F Miller
- Aging and Metabolism Research Program, Oklahoma Medical Research Foundation, Oklahoma City, USA
| | - Timothy A Butterfield
- Center for Muscle Biology, University of Kentucky, Lexington, USA
- Department of Athletic Training and Clinical Nutrition, College of Health Sciences, University of Kentucky, Lexington, USA
| | - Esther E Dupont-Versteegden
- Department of Physical Therapy, College of Health Sciences, University of Kentucky, Lexington, USA
- Center for Muscle Biology, University of Kentucky, Lexington, USA
| |
Collapse
|
5
|
Bengtsen M, Winje IM, Eftestøl E, Landskron J, Sun C, Nygård K, Domanska D, Millay DP, Meza-Zepeda LA, Gundersen K. Comparing the epigenetic landscape in myonuclei purified with a PCM1 antibody from a fast/glycolytic and a slow/oxidative muscle. PLoS Genet 2021; 17:e1009907. [PMID: 34752468 PMCID: PMC8604348 DOI: 10.1371/journal.pgen.1009907] [Citation(s) in RCA: 7] [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: 05/07/2021] [Revised: 11/19/2021] [Accepted: 10/23/2021] [Indexed: 01/04/2023] Open
Abstract
Muscle cells have different phenotypes adapted to different usage, and can be grossly divided into fast/glycolytic and slow/oxidative types. While most muscles contain a mixture of such fiber types, we aimed at providing a genome-wide analysis of the epigenetic landscape by ChIP-Seq in two muscle extremes, the fast/glycolytic extensor digitorum longus (EDL) and slow/oxidative soleus muscles. Muscle is a heterogeneous tissue where up to 60% of the nuclei can be of a different origin. Since cellular homogeneity is critical in epigenome-wide association studies we developed a new method for purifying skeletal muscle nuclei from whole tissue, based on the nuclear envelope protein Pericentriolar material 1 (PCM1) being a specific marker for myonuclei. Using antibody labelling and a magnetic-assisted sorting approach, we were able to sort out myonuclei with 95% purity in muscles from mice, rats and humans. The sorting eliminated influence from the other cell types in the tissue and improved the myo-specific signal. A genome-wide comparison of the epigenetic landscape in EDL and soleus reflected the differences in the functional properties of the two muscles, and revealed distinct regulatory programs involving distal enhancers, including a glycolytic super-enhancer in the EDL. The two muscles were also regulated by different sets of transcription factors; e.g. in soleus, binding sites for MEF2C, NFATC2 and PPARA were enriched, while in EDL MYOD1 and SIX1 binding sites were found to be overrepresented. In addition, more novel transcription factors for muscle regulation such as members of the MAF family, ZFX and ZBTB14 were identified. Complex tissues like skeletal muscle contain a variety of cells which confound the analysis of each cell type when based on homogenates, thus only about half of the cell nuclei in muscles reside inside the muscle cells. We here describe a labelling and sorting technique that allowed us to study the epigenetic landscape in purified muscle cell nuclei leaving the other cell types out. Differences between a fast/glycolytic and a slow/oxidative muscle were studied. While all skeletal muscle fibers have a similar make up and basic function, they differ in their physiology and the way they are used. Thus, some fibers are fast contracting but fatigable, and are used for short lasting explosive tasks such as sprinting. Other fibers are slow and are used for more prolonged tasks such as standing or long distance running. Since fiber type correlate with metabolic profile these features can also be related to metabolic diseases. We here show that the epigenetic landscape differed in gene loci corresponding to the differences in functional properties, and revealed that the two types are enriched in different gene regulatory networks. Exercise can alter muscle phenotype, and the epigenetic landscape might be related to how plastic different properties are.
Collapse
Affiliation(s)
- Mads Bengtsen
- Department of Biosciences, University of Oslo, Oslo, Norway
| | | | - Einar Eftestøl
- Department of Biosciences, University of Oslo, Oslo, Norway
- Division of Molecular Cardiovascular Biology, Cincinnati Children’s Hospital Medical Center, Cincinnati, Ohio, United States of America
| | | | - Chengyi Sun
- Division of Molecular Cardiovascular Biology, Cincinnati Children’s Hospital Medical Center, Cincinnati, Ohio, United States of America
| | - Kamilla Nygård
- Department of Biosciences, University of Oslo, Oslo, Norway
| | - Diana Domanska
- Department of Pathology, University of Oslo, Oslo, Norway
| | - Douglas P. Millay
- Division of Molecular Cardiovascular Biology, Cincinnati Children’s Hospital Medical Center, Cincinnati, Ohio, United States of America
- Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, Ohio, United States of America
| | - Leonardo A. Meza-Zepeda
- Department of Core Facilities, Institute for Cancer Research, Oslo University Hospital, Oslo, Norway
| | | |
Collapse
|
6
|
Eftestøl E, Franchi MV, Kasper S, Flück M. JNK activation in TA and EDL muscle is load-dependent in rats receiving identical excitation patterns. Sci Rep 2021; 11:16405. [PMID: 34385505 PMCID: PMC8361015 DOI: 10.1038/s41598-021-94930-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2021] [Accepted: 07/12/2021] [Indexed: 11/09/2022] Open
Abstract
As the excitation-contraction coupling is inseparable during voluntary exercise, the relative contribution of the mechanical and neural input on hypertrophy-related molecular signalling is still poorly understood. Herein, we use a rat in-vivo strength exercise model with an electrically-induced standardized excitation pattern, previously shown to induce a load-dependent increase in myonuclear number and hypertrophy, to study acute effects of load on molecular signalling. We assessed protein abundance and specific phosphorylation of the four protein kinases FAK, mTOR, p70S6K and JNK after 2, 10 and 28 min of a low- or high-load contraction, in order to assess the effects of load, exercise duration and muscle-type on their response to exercise. Specific phosphorylation of mTOR, p70S6K and JNK was increased after 28 min of exercise under the low- and high-load protocol. Elevated phosphorylation of mTOR and JNK was detectable already after 2 and 10 min of exercise, respectively, but greatest after 28 min of exercise, and JNK phosphorylation was highly load-dependent. The abundance of all four kinases was higher in TA compared to EDL muscle, p70S6K abundance was increased after exercise in a load-independent manner, and FAK and JNK abundance was reduced after 28 min of exercise in both the exercised and control muscles. In conclusion, the current study shows that JNK activation after a single resistance exercise is load-specific, resembling the previously reported degree of myonuclear accrual and muscle hypertrophy with repetition of the exercise stimulus.
Collapse
Affiliation(s)
- Einar Eftestøl
- Department of Biosciences, University of Oslo, Kristine Bonnevies hus, Blindernveien 31, 0371, Oslo, Norway.
| | - Martino V Franchi
- Laboratory for Muscle Plasticity, Department of Orthopaedics, University of Zürich, Zurich, Switzerland.,Department of Biomedical Sciences, University of Padova, Padua, Italy
| | - Stephanie Kasper
- Laboratory for Muscle Plasticity, Department of Orthopaedics, University of Zürich, Zurich, Switzerland
| | - Martin Flück
- Laboratory for Muscle Plasticity, Department of Orthopaedics, University of Zürich, Zurich, Switzerland
| |
Collapse
|
7
|
Millward DJ. Interactions between Growth of Muscle and Stature: Mechanisms Involved and Their Nutritional Sensitivity to Dietary Protein: The Protein-Stat Revisited. Nutrients 2021; 13:729. [PMID: 33668846 PMCID: PMC7996181 DOI: 10.3390/nu13030729] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2021] [Revised: 02/15/2021] [Accepted: 02/22/2021] [Indexed: 02/07/2023] Open
Abstract
Childhood growth and its sensitivity to dietary protein is reviewed within a Protein-Stat model of growth regulation. The coordination of growth of muscle and stature is a combination of genetic programming, and of two-way mechanical interactions involving the mechanotransduction of muscle growth through stretching by bone length growth, the core Protein-Stat feature, and the strengthening of bone through muscle contraction via the mechanostat. Thus, growth in bone length is the initiating event and this is always observed. Endocrine and cellular mechanisms of growth in stature are reviewed in terms of the growth hormone-insulin like growth factor-1 (GH-IGF-1) and thyroid axes and the sex hormones, which together mediate endochondral ossification in the growth plate and bone lengthening. Cellular mechanisms of muscle growth during development are then reviewed identifying (a) the difficulties posed by the need to maintain its ultrastructure during myofibre hypertrophy within the extracellular matrix and the concept of muscle as concentric "bags" allowing growth to be conceived as bag enlargement and filling, (b) the cellular and molecular mechanisms involved in the mechanotransduction of satellite and mesenchymal stromal cells, to enable both connective tissue remodelling and provision of new myonuclei to aid myofibre hypertrophy and (c) the implications of myofibre hypertrophy for protein turnover within the myonuclear domain. Experimental data from rodent and avian animal models illustrate likely changes in DNA domain size and protein turnover during developmental and stretch-induced muscle growth and between different muscle fibre types. Growth of muscle in male rats during adulthood suggests that "bag enlargement" is achieved mainly through the action of mesenchymal stromal cells. Current understanding of the nutritional regulation of protein deposition in muscle, deriving from experimental studies in animals and human adults, is reviewed, identifying regulation by amino acids, insulin and myofibre volume changes acting to increase both ribosomal capacity and efficiency of muscle protein synthesis via the mechanistic target of rapamycin complex 1 (mTORC1) and the phenomenon of a "bag-full" inhibitory signal has been identified in human skeletal muscle. The final section deals with the nutritional sensitivity of growth of muscle and stature to dietary protein in children. Growth in length/height as a function of dietary protein intake is described in the context of the breastfed child as the normative growth model, and the "Early Protein Hypothesis" linking high protein intakes in infancy to later adiposity. The extensive paediatric studies on serum IGF-1 and child growth are reviewed but their clinical relevance is of limited value for understanding growth regulation; a role in energy metabolism and homeostasis, acting with insulin to mediate adiposity, is probably more important. Information on the influence of dietary protein on muscle mass per se as opposed to lean body mass is limited but suggests that increased protein intake in children is unable to promote muscle growth in excess of that linked to genotypic growth in length/height. One possible exception is milk protein intake, which cohort and cross-cultural studies suggest can increase height and associated muscle growth, although such effects have yet to be demonstrated by randomised controlled trials.
Collapse
Affiliation(s)
- D Joe Millward
- Department of Nutritional Sciences, Faculty of Health and Medical Sciences, University of Surrey, Guildford GU2 7XH, UK
| |
Collapse
|
8
|
Eftestøl E. Excitation and tension development-The Yin & Yang of muscle signalling. Acta Physiol (Oxf) 2021; 231:e13575. [PMID: 33135293 DOI: 10.1111/apha.13575] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Affiliation(s)
- Einar Eftestøl
- Department of Biosciences University of Oslo Oslo Norway
| |
Collapse
|
9
|
Rindom E, Herskind J, Blaauw B, Overgaard K, Vissing K, Paoli FV. Concomitant excitation and tension development are required for myocellular gene expression and protein synthesis in rat skeletal muscle. Acta Physiol (Oxf) 2021; 231:e13540. [PMID: 32687678 DOI: 10.1111/apha.13540] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2019] [Revised: 07/12/2020] [Accepted: 07/14/2020] [Indexed: 02/06/2023]
Abstract
AIM Loading-induced tension development is often assumed to constitute an independent cue to initiate muscle protein synthesis following resistance exercise. However, with traditional physiological models of resistance exercise, changes in loading-induced tension development also reflect changes in neural activation patterns, and direct evidence for a mechanosensitive mechanism is therefore limited. Here, we sought to examine the importance of excitation and tension development per se on initiation of signalling, gene transcription and protein synthesis in rat skeletal muscle. METHODS Isolated rat extensor digitorum longus muscles were allocated to the following interventions: (a) Excitation-induced eccentric contractions (ECC); (b) Passive stretching without excitation (PAS); (c) Excitation with inhibition of contractions (STIM + IMA ) and; (d) Excitation in combination with both inhibition of contractions and PAS (STIM + IMA + PAS). Assessment of transcriptional and translational signalling, gene transcription and acute muscle protein synthesis was compared in stimulated vs contra-lateral non-stimulated control muscle. RESULTS Protein synthesis increased solely in muscles subjected to a combination of excitation and tension development (ECC and STIM + IMA + PAS). The same pattern was true for p38 mitogen-activated protein kinase signalling for gene transcription as well as for gene transcription of immediate early genes FOS and JUN. In contrast, mechanistic target of rapamycin Complex 1 signalling for translation initiation increased in all muscles subjected to increased tension development (ECC and STIM + IMA + PAS as well as PAS). CONCLUSIONS The current study suggests that exercise-induced increases in protein synthesis as well as transcriptional signalling is dependent on the concomitant effect of excitation and tension development, whereas signalling for translation initiation is only dependent of tension development per se.
Collapse
Affiliation(s)
- Emil Rindom
- Department of Biomedicine Aarhus University Aarhus Denmark
| | - Jon Herskind
- Section for Sport Science Department of Public Health Aarhus University Aarhus Denmark
| | - Bert Blaauw
- Department of Biomedical Sciences University of Padova Padova Italy
| | - Kristian Overgaard
- Section for Sport Science Department of Public Health Aarhus University Aarhus Denmark
| | - Kristian Vissing
- Section for Sport Science Department of Public Health Aarhus University Aarhus Denmark
| | - Frank V. Paoli
- Department of Biomedicine Aarhus University Aarhus Denmark
| |
Collapse
|
10
|
Rønning SB, Carlson CR, Aronsen JM, Pisconti A, Høst V, Lunde M, Liland KH, Sjaastad I, Kolset SO, Christensen G, Pedersen ME. Syndecan-4 -/- Mice Have Smaller Muscle Fibers, Increased Akt/mTOR/S6K1 and Notch/HES-1 Pathways, and Alterations in Extracellular Matrix Components. Front Cell Dev Biol 2020; 8:730. [PMID: 32850844 PMCID: PMC7411008 DOI: 10.3389/fcell.2020.00730] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2020] [Accepted: 07/15/2020] [Indexed: 12/11/2022] Open
Abstract
Background Extracellular matrix (ECM) remodeling is essential for skeletal muscle development and adaption in response to environmental cues such as exercise and injury. The cell surface proteoglycan syndecan-4 has been reported to be essential for muscle differentiation, but few molecular mechanisms are known. Syndecan-4–/– mice are unable to regenerate damaged muscle, and display deficient satellite cell activation, proliferation, and differentiation. A reduced myofiber basal lamina has also been reported in syndecan-4–/– muscle, indicating possible defects in ECM production. To get a better understanding of the underlying molecular mechanisms, we have here investigated the effects of syndecan-4 genetic ablation on molecules involved in ECM remodeling and muscle growth, both under steady state conditions and in response to exercise. Methods Tibialis anterior (TA) muscles from sedentary and exercised syndecan-4–/– and WT mice were analyzed by immunohistochemistry, real-time PCR and western blotting. Results Compared to WT, we found that syndecan-4–/– mice had reduced body weight, reduced muscle weight, muscle fibers with a smaller cross-sectional area, and reduced expression of myogenic regulatory transcription factors. Sedentary syndecan-4–/– had also increased mRNA levels of syndecan-2, decorin, collagens, fibromodulin, biglycan, and LOX. Some of these latter ECM components were reduced at protein level, suggesting them to be more susceptible to degradation or less efficiently translated when syndecan-4 is absent. At the protein level, TRPC7 was reduced, whereas activation of the Akt/mTOR/S6K1 and Notch/HES-1 pathways were increased. Finally, although exercise induced upregulation of several of these components in WT, a further upregulation of these molecules was not observed in exercised syndecan-4–/– mice. Conclusion Altogether our data suggest an important role of syndecan-4 in muscle development.
Collapse
Affiliation(s)
| | - Cathrine Rein Carlson
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Oslo, Norway
| | - Jan Magnus Aronsen
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Oslo, Norway.,Bjørknes College, Oslo, Norway
| | - Addolorata Pisconti
- Department of Biochemistry and Cell Biology, Stony Brook University, Stony Brook, NY, United States
| | | | - Marianne Lunde
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Oslo, Norway
| | - Kristian Hovde Liland
- Nofima AS, Ås, Norway.,Faculty of Sciences and Technology, Norwegian University of Life Sciences, Ås, Norway
| | - Ivar Sjaastad
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Oslo, Norway.,K.G. Jebsen Center for Cardiac Research, University of Oslo, Oslo, Norway
| | - Svein Olav Kolset
- Department of Nutrition, Institute of Basic Medical Sciences, University of Oslo, Oslo, Norway
| | - Geir Christensen
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Oslo, Norway.,K.G. Jebsen Center for Cardiac Research, University of Oslo, Oslo, Norway
| | | |
Collapse
|
11
|
A focused review of myokines as a potential contributor to muscle hypertrophy from resistance-based exercise. Eur J Appl Physiol 2020; 120:941-959. [PMID: 32144492 DOI: 10.1007/s00421-020-04337-1] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2019] [Accepted: 02/27/2020] [Indexed: 02/07/2023]
Abstract
PURPOSE Resistance exercise induces muscle growth and is an important treatment for age-related losses in muscle mass and strength. Myokines are hypothesized as a signal conveying physiological information to skeletal muscle, possibly to "fine-tune" other regulatory pathways. While myokines are released from skeletal muscle following contraction, their role in increasing muscle mass and strength in response to resistance exercise or training is not established. Recent research identified both local and systemic release of myokines after an acute bout of resistance exercise. However, it is not known whether myokines with putative anabolic function are mechanistically involved in producing muscle hypertrophy after resistance exercise. Further, nitric oxide (NO), an important mediator of muscle stem cell activation, upregulates the expression of certain myokine genes in skeletal muscle. METHOD In the systemic context of complex hypertrophic signaling, this review: (1) summarizes literature on several well-recognized, representative myokines with anabolic potential; (2) explores the potential mechanistic role of myokines in skeletal muscle hypertrophy; and (3) identifies future research required to advance our understanding of myokine anabolism specifically in skeletal muscle. RESULT This review establishes a link between myokines and NO production, and emphasizes the importance of considering systemic release of potential anabolic myokines during resistance exercise as complementary to other signals that promote hypertrophy. CONCLUSION Investigating adaptations to resistance exercise in aging opens a novel avenue of interdisciplinary research into myokines and NO metabolites during resistance exercise, with the longer-term goal to improve muscle health in daily living, aging, and rehabilitation.
Collapse
|
12
|
Russell CS, Mostafavi A, Quint JP, Panayi AC, Baldino K, Williams TJ, Daubendiek JG, Hugo Sánchez V, Bonick Z, Trujillo-Miranda M, Shin SR, Pourquie O, Salehi S, Sinha I, Tamayol A. In Situ Printing of Adhesive Hydrogel Scaffolds for the Treatment of Skeletal Muscle Injuries. ACS APPLIED BIO MATERIALS 2020; 3:1568-1579. [DOI: 10.1021/acsabm.9b01176] [Citation(s) in RCA: 58] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Affiliation(s)
- Carina S. Russell
- Department of Mechanical and Materials Engineering, University of Nebraska, 900 North 16th Street, Room NH W330, Lincoln, Nebraska 68588, United States
| | - Azadeh Mostafavi
- Department of Mechanical and Materials Engineering, University of Nebraska, 900 North 16th Street, Room NH W330, Lincoln, Nebraska 68588, United States
| | - Jacob P. Quint
- Department of Mechanical and Materials Engineering, University of Nebraska, 900 North 16th Street, Room NH W330, Lincoln, Nebraska 68588, United States
| | - Adriana C. Panayi
- Division of Plastic Surgery, Brigham and Women’s Hospital, Harvard Medical School, 75 Francis Street, Boston, Massachusetts 02115, United States
| | - Kodi Baldino
- Division of Plastic Surgery, Brigham and Women’s Hospital, Harvard Medical School, 75 Francis Street, Boston, Massachusetts 02115, United States
| | - Tyrell J. Williams
- Department of Mechanical and Materials Engineering, University of Nebraska, 900 North 16th Street, Room NH W330, Lincoln, Nebraska 68588, United States
| | - Jocelyn G. Daubendiek
- Department of Mechanical and Materials Engineering, University of Nebraska, 900 North 16th Street, Room NH W330, Lincoln, Nebraska 68588, United States
| | - Victor Hugo Sánchez
- Department of Mechanical and Materials Engineering, University of Nebraska, 900 North 16th Street, Room NH W330, Lincoln, Nebraska 68588, United States
| | - Zack Bonick
- Department of Mechanical and Materials Engineering, University of Nebraska, 900 North 16th Street, Room NH W330, Lincoln, Nebraska 68588, United States
| | | | - Su Ryon Shin
- Department of Medicine, Brigham and Women’s Hospital, Harvard Medical School, Boston, Massachusetts 02139, United States
| | - Olivier Pourquie
- Department of Pathology, Brigham and Women’s Hospital, Harvard Medical School, Boston, Massachusetts 02115, United States
| | - Sahar Salehi
- Chair of Biomaterials, University of Bayreuth, Bayreuth, 95447 Germany
| | - Indranil Sinha
- Division of Plastic Surgery, Brigham and Women’s Hospital, Harvard Medical School, 75 Francis Street, Boston, Massachusetts 02115, United States
| | - Ali Tamayol
- Department of Mechanical and Materials Engineering, University of Nebraska, 900 North 16th Street, Room NH W330, Lincoln, Nebraska 68588, United States
| |
Collapse
|
13
|
Hammarström D, Øfsteng S, Koll L, Hanestadhaugen M, Hollan I, Apró W, Whist JE, Blomstrand E, Rønnestad BR, Ellefsen S. Benefits of higher resistance-training volume are related to ribosome biogenesis. J Physiol 2020; 598:543-565. [PMID: 31813190 DOI: 10.1113/jp278455] [Citation(s) in RCA: 46] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2019] [Accepted: 12/03/2019] [Indexed: 12/25/2022] Open
Abstract
KEY POINTS For individuals showing suboptimal adaptations to resistance training, manipulation of training volume is a potential measure to facilitate responses. This remains unexplored. Here, 34 untrained individuals performed contralateral resistance training with moderate and low volume for 12 weeks. Moderate volume led to larger increases in muscle cross-sectional area, strength and type II fibre-type transitions. These changes coincided with greater activation of signalling pathways controlling muscle growth and greater induction of ribosome synthesis. Out of 34 participants, thirteen displayed clear benefit of MOD on muscle hypertrophy and sixteen showed clear benefit of MOD on muscle strength gains. This coincided with greater total RNA accumulation in the early phase of the training period, suggesting that ribosomal biogenesis regulates the dose-response relationship between training volume and muscle hypertrophy. These results demonstrate that there is a dose-dependent relationship between training volume and outcomes. On the individual level, benefits of higher training volume were associated with increased ribosomal biogenesis. ABSTRACT Resistance-exercise volume is a determinant of training outcomes. However not all individuals respond in a dose-dependent fashion. In this study, 34 healthy individuals (males n = 16, 23.6 (4.1) years; females n = 18, 22.0 (1.3) years) performed moderate- (3 sets per exercise, MOD) and low-volume (1 set, LOW) resistance training in a contralateral fashion for 12 weeks (2-3 sessions per week). Muscle cross-sectional area (CSA) and strength were assessed at Weeks 0 and 12, along with biopsy sampling (m. vastus lateralis). Muscle biopsies were also sampled before and 1 h after the fifth session (Week 2). MOD resulted in larger increases in muscle CSA (5.2 (3.8)% versus 3.7 (3.7)%, P < 0.001) and strength (3.4-7.7% difference, all P < 0.05. This coincided with greater reductions in type IIX fibres from Week 0 to Week 12 (MOD, -4.6 percentage points; LOW -3.2 percentage points), greater phosphorylation of S6-kinase 1 (p85 S6K1Thr412 , 19%; p70 S6K1Thr389 , 58%) and ribosomal protein S6Ser235/236 (37%), greater rested-state total RNA (8.8%) and greater exercise-induced c-Myc mRNA expression (25%; Week 2, all P < 0.05). Thirteen and sixteen participants, respectively, displayed clear benefits in response to MOD on muscle hypertrophy and strength. Benefits were associated with greater accumulation of total RNA at Week 2 in the MOD leg, with every 1% difference increasing the odds of MOD benefit by 7.0% (P = 0.005) and 9.8% (P = 0.002). In conclusion, MOD led to greater functional and biological adaptations than LOW. Associations between dose-dependent total RNA accumulation and increases in muscle mass and strength point to ribosome biogenesis as a determinant of dose-dependent training responses.
Collapse
Affiliation(s)
- Daniel Hammarström
- Section for Health and Exercise Physiology, Department of Public Health and Sport Sciences, Inland Norway University of Applied Sciences, Elverum, Norway.,Swedish School of Sport and Health Sciences, Box 5626, SE-114 86, Stockholm, Sweden
| | - Sjur Øfsteng
- Section for Health and Exercise Physiology, Department of Public Health and Sport Sciences, Inland Norway University of Applied Sciences, Elverum, Norway
| | - Lise Koll
- Innlandet Hospital Trust, Postboks 990, 2629, Lillehammer, Norway
| | | | - Ivana Hollan
- Hospital for Rheumatic Diseases, Magrethe Grundtvigsvei 6, 2609, Lillehammer, Norway.,Brigham and Women's Hospital, 75 Francis Street, Boston, MA, 02115, USA
| | - William Apró
- Swedish School of Sport and Health Sciences, Box 5626, SE-114 86, Stockholm, Sweden
| | - Jon Elling Whist
- Innlandet Hospital Trust, Postboks 990, 2629, Lillehammer, Norway
| | - Eva Blomstrand
- Swedish School of Sport and Health Sciences, Box 5626, SE-114 86, Stockholm, Sweden
| | - Bent R Rønnestad
- Section for Health and Exercise Physiology, Department of Public Health and Sport Sciences, Inland Norway University of Applied Sciences, Elverum, Norway
| | - Stian Ellefsen
- Section for Health and Exercise Physiology, Department of Public Health and Sport Sciences, Inland Norway University of Applied Sciences, Elverum, Norway.,Innlandet Hospital Trust, Postboks 990, 2629, Lillehammer, Norway
| |
Collapse
|
14
|
Rindom E, Kristensen AM, Overgaard K, Vissing K, Paoli FV. Activation of mTORC1 signalling in rat skeletal muscle is independent of the EC-coupling sequence but dependent on tension per se in a dose-response relationship. Acta Physiol (Oxf) 2019; 227:e13336. [PMID: 31231946 DOI: 10.1111/apha.13336] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2019] [Revised: 06/04/2019] [Accepted: 06/20/2019] [Indexed: 12/29/2022]
Abstract
AIM mTORC1 is regarded as an important key regulator of protein synthesis and hypertrophy following mechanical stimuli in skeletal muscle. However, as excitation and tension development is tightly coupled in most experimental models, very little and largely indirect evidence exist for such a mechanosensitive pathway. Here, we sought to examine whether activation of mTORC1 signalling is dependent on tension per se in rat skeletal muscle. METHODS To examine the mechanosensitivity of mTORC1, rat EDL muscles were exposed to either excitation-induced eccentric contractions (ECC), passive stretching (PAS) with identical peak tension (Tpeak ) and Tension-Time-Integral (TTI), or ECC with addition of inhibitors of the myosin ATPases (IMA ). To further explore the relationship between tension and mTORC1 signalling, rat EDL muscles were subjected to PAS of different magnitudes of Tpeak while standardizing TTI and vice versa. RESULTS PAS and ECC with equal Tpeak and TTI produced similar responses in mTORC1 signalling despite different modes of tension development. When active tension during ECC was nearly abolished by addition of IMA , mTORC1 signalling was reduced to a level comparable to non-stimulated controls. In addition, when muscles were exposed to PAS of varying levels of Tpeak with standardized TTI, activation of mTORC1 signalling displayed a positive relationship with peak tension. CONCLUSIONS The current study directly links tension per se to activation of mTORC1 signalling, which is independent of an active EC-coupling sequence. Moreover, activation of mTORC1 signalling displays a positive dose-response relationship with peak tension.
Collapse
Affiliation(s)
- Emil Rindom
- Department of Biomedicine Aarhus University Aarhus Denmark
| | - Anders M. Kristensen
- Section for Sport Science, Department of Public Health Aarhus University Aarhus Denmark
| | - Kristian Overgaard
- Section for Sport Science, Department of Public Health Aarhus University Aarhus Denmark
| | - Kristian Vissing
- Section for Sport Science, Department of Public Health Aarhus University Aarhus Denmark
| | | |
Collapse
|
15
|
Jin J, Bakker AD, Wu G, Klein-Nulend J, Jaspers RT. Physicochemical Niche Conditions and Mechanosensing by Osteocytes and Myocytes. Curr Osteoporos Rep 2019; 17:235-249. [PMID: 31428977 PMCID: PMC6817749 DOI: 10.1007/s11914-019-00522-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
PURPOSE OF REVIEW Bone and muscle mass increase in response to mechanical loading and biochemical cues. Bone-forming osteoblasts differentiate into early osteocytes which ultimately mature into late osteocytes encapsulated in stiff calcified matrix. Increased muscle mass originates from muscle stem cells (MuSCs) enclosed between their plasma membrane and basal lamina. Stem cell fate and function are strongly determined by physical and chemical properties of their microenvironment, i.e., the cell niche. RECENT FINDINGS The cellular niche is a three-dimensional structure consisting of extracellular matrix components, signaling molecules, and/or other cells. Via mechanical interaction with their niche, osteocytes and MuSCs are subjected to mechanical loads causing deformations of membrane, cytoskeleton, and/or nucleus, which elicit biochemical responses and secretion of signaling molecules into the niche. The latter may modulate metabolism, morphology, and mechanosensitivity of the secreting cells, or signal to neighboring cells and cells at a distance. Little is known about how mechanical loading of bone and muscle tissue affects osteocytes and MuSCs within their niches. This review provides an overview of physicochemical niche conditions of (early) osteocytes and MuSCs and how these are sensed and determine cell fate and function. Moreover, we discuss how state-of-the-art imaging techniques may enhance our understanding of these conditions and mechanisms.
Collapse
Affiliation(s)
- Jianfeng Jin
- Department of Oral Cell Biology, Academic Centre for Dentistry Amsterdam (ACTA), University of Amsterdam and Vrije Universiteit Amsterdam, Amsterdam Movement Sciences, Amsterdam, The Netherlands
| | - Astrid D Bakker
- Department of Oral Cell Biology, Academic Centre for Dentistry Amsterdam (ACTA), University of Amsterdam and Vrije Universiteit Amsterdam, Amsterdam Movement Sciences, Amsterdam, The Netherlands
| | - Gang Wu
- Department of Oral Implantology and Prosthetic Dentistry, Academic Centre for Dentistry Amsterdam (ACTA), University of Amsterdam and Vrije Universiteit Amsterdam, Amsterdam Movement Sciences, Amsterdam, The Netherlands
| | - Jenneke Klein-Nulend
- Department of Oral Cell Biology, Academic Centre for Dentistry Amsterdam (ACTA), University of Amsterdam and Vrije Universiteit Amsterdam, Amsterdam Movement Sciences, Amsterdam, The Netherlands
| | - Richard T Jaspers
- Laboratory for Myology, Faculty of Behavioral and Movement Sciences, Vrije Universiteit Amsterdam, Amsterdam Movement Sciences, De Boelelaan 1108, 1081 HZ, Amsterdam, The Netherlands.
| |
Collapse
|
16
|
Winje IM, Sheng X, Hansson K, Solbrå A, Tennøe S, Saatcioglu F, Bruusgaard JC, Gundersen K. Cachexia does not induce loss of myonuclei or muscle fibres during xenografted prostate cancer in mice. Acta Physiol (Oxf) 2019; 225:e13204. [PMID: 30325108 DOI: 10.1111/apha.13204] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2018] [Revised: 10/02/2018] [Accepted: 10/08/2018] [Indexed: 12/25/2022]
Abstract
AIM Cachexia is a severe wasting disorder involving loss of body- and muscle mass reducing survival and quality of life in cancer patients. We aim at determining if cachexia is a mere perturbation of the protein balance or if the condition also involves a degenerative loss of myonuclei within the fibre syncytia or loss of whole muscle fibres. METHODS We induced cachexia by xenografting PC3 prostate cancer cells in nu/nu mice. Six weeks later, we counted myonuclei by in vivo microscopic imaging of single live fibres in the extensor digitorum longus muscle (EDL), and the EDL, soleus and tibialis anterior muscles were also harvested for ex vivo histology. RESULTS The mice lost on average 15% of the whole-body wt. The muscle wet weight of the glycolytic, fast EDL was reduced by 14%, the tibialis anterior by 17%, and the slow, oxidative soleus by 6%. The fibre cross-sectional area in the EDL was reduced by 21% with no loss of myonuclei or any significant reduction in the number of muscle fibres. TUNEL-positive nuclei or fibres with embryonic myosin were rare both in cachectic and control muscles, and haematoxylin-eosin staining revealed no clear signs of muscle pathology. CONCLUSION The data suggest that the cachexia induced by xenografted prostate tumours induces a pronounced atrophy not accompanied by a loss of myonuclei or a loss of muscle fibres. Thus, stem cell related treatment might be redundant, and the quest for treatment options should rather focus on intervening with intracellular pathways regulating muscle fibre size.
Collapse
Affiliation(s)
| | - Xia Sheng
- Department of Biosciences University of Oslo Oslo Norway
| | - Kenth‐Arne Hansson
- Department of Biosciences University of Oslo Oslo Norway
- Center for Integrative Neuroplasticity (CINPLA) University of Oslo Oslo Norway
| | - Andreas Solbrå
- Center for Integrative Neuroplasticity (CINPLA) University of Oslo Oslo Norway
- Department of Physics University of Oslo Oslo Norway
| | - Simen Tennøe
- Center for Integrative Neuroplasticity (CINPLA) University of Oslo Oslo Norway
- Department of Informatics University of Oslo Oslo Norway
| | - Fahri Saatcioglu
- Department of Biosciences University of Oslo Oslo Norway
- Institute of Cancer Genetics and Informatics Oslo University Hospital Oslo Norway
| | - Jo Christiansen Bruusgaard
- Department of Biosciences University of Oslo Oslo Norway
- Center for Integrative Neuroplasticity (CINPLA) University of Oslo Oslo Norway
- Department of Health Sciences Kristiania University College Oslo Norway
| | - Kristian Gundersen
- Department of Biosciences University of Oslo Oslo Norway
- Center for Integrative Neuroplasticity (CINPLA) University of Oslo Oslo Norway
| |
Collapse
|
17
|
Olsen LA, Nicoll JX, Fry AC. The skeletal muscle fiber: a mechanically sensitive cell. Eur J Appl Physiol 2019; 119:333-349. [PMID: 30612167 DOI: 10.1007/s00421-018-04061-x] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2018] [Accepted: 12/21/2018] [Indexed: 12/12/2022]
Abstract
The plasticity of skeletal muscle, whether an increase in size, change in metabolism, or alteration in structural properties, is in a continuous state of flux largely dependent upon physical activity. Much of the past research has expounded upon these ever-changing aspects of the muscle fiber following exercise. Specifically, endocrine and paracrine signaling have been heavily investigated lending to much of the past literature comprised of such endocrinological dynamics following muscle activity. Mechanotransduction, the ability of a cell to convert a mechanical stimulus into an intracellular biochemical response, has garnered much less attention. Recent work, however, has demonstrated the physical continuity of the muscle fiber, specifically demonstrating a continuous physical link between the extracellular matrix (ECM), cytoskeleton, and nuclear matrix as a means to rapidly regulate gene expression following a mechanical stimulus. Similarly, research has shown mechanical stimuli to directly influence cytoplasmic signaling whether through oxidative adaptations, increased muscle size, or enhanced muscle integrity. Regrettably, minimal research has investigated the role that exercise may play within the mechanotransducing signaling cascades. This proposed line of study may prove paramount as muscle-related diseases greatly impact one's ability to lead an independent lifestyle along with contributing a substantial burden upon the economy. Thus, this review explores both biophysical and biochemical mechanotransduction, and how these signaling pathways may be influenced following exercise.
Collapse
Affiliation(s)
- Luke A Olsen
- Biomedical Sciences, University of Kansas Medical Center, Kansas City, KS, 66160, USA
| | - Justin X Nicoll
- Department of Kinesiology, California State University, Northridge, CA, 91330-8287, USA
| | - Andrew C Fry
- Department of Health, Sport, and Exercise Sciences, University of Kansas, Lawrence, KS, 66045, USA.
| |
Collapse
|
18
|
Winje IM, Bengtsen M, Eftestøl E, Juvkam I, Bruusgaard JC, Gundersen K. Specific labelling of myonuclei by an antibody against pericentriolar material 1 on skeletal muscle tissue sections. Acta Physiol (Oxf) 2018; 223:e13034. [PMID: 29330928 DOI: 10.1111/apha.13034] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2017] [Revised: 01/05/2018] [Accepted: 01/08/2018] [Indexed: 01/11/2023]
Abstract
AIM Skeletal muscle is a heterogeneous tissue containing several different cell types, and only about 40%-50% of the cell nuclei within the tissue belong to myofibres. Existing technology, attempting to distinguish myonuclei from other nuclei at the light microscopy level, has led to controversies in our understanding of the basic cell biology of muscle plasticity. This study aims at demonstrating that an antibody against the protein pericentriolar material 1 (PCM1) can be used to reliably identify myonuclei on histological cross sections from humans, mice and rats. METHODS Cryosections were labelled with a polyclonal antibody against PCM1. The specificity of the labelling for myonuclei was verified using 3D reconstructions of confocal z-stacks triple-labelled for DNA, dystrophin and PCM1, and by co-localization with nuclear mCherry driven by the muscle-specific Alpha-Actin-1 promoter after viral transduction. RESULTS The PCM1 antibody specifically labelled all myonuclei, and myonuclei only, in cryosections of muscles from rats, mice and men. Nuclei in other cell types including satellite cells were not labelled. Both normal muscles and hypertrophic muscles after synergist ablation were investigated. CONCLUSION Pericentriolar material 1 can be used as a specific histological marker for myonuclei in skeletal muscle tissue without relying on counterstaining of other structures or cumbersome and subjective analysis of nuclear positioning.
Collapse
Affiliation(s)
- I M Winje
- Department of Biosciences, University of Oslo, Oslo, Norway
| | - M Bengtsen
- Department of Biosciences, University of Oslo, Oslo, Norway
| | - E Eftestøl
- Department of Biosciences, University of Oslo, Oslo, Norway
| | - I Juvkam
- Department of Biosciences, University of Oslo, Oslo, Norway
| | - J C Bruusgaard
- Department of Biosciences, University of Oslo, Oslo, Norway
- Department of Health Sciences, Kristiania University College, Oslo, Norway
| | - K Gundersen
- Department of Biosciences, University of Oslo, Oslo, Norway
| |
Collapse
|
19
|
Bamman MM, Roberts BM, Adams GR. Molecular Regulation of Exercise-Induced Muscle Fiber Hypertrophy. Cold Spring Harb Perspect Med 2018; 8:cshperspect.a029751. [PMID: 28490543 DOI: 10.1101/cshperspect.a029751] [Citation(s) in RCA: 54] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Skeletal muscle hypertrophy is a widely sought exercise adaptation to counteract the muscle atrophy of aging and disease, or to improve athletic performance. While this desired muscle enlargement is a well-known adaptation to resistance exercise training (RT), the mechanistic underpinnings are not fully understood. The purpose of this review is thus to provide the reader with a summary of recent advances in molecular mechanisms-based on the most current literature-that are thought to promote RT-induced muscle hypertrophy. We have therefore focused this discussion on the following areas of fertile investigation: ribosomal function and biogenesis, muscle stem (satellite) cell activity, transcriptional regulation, mechanotransduction, and myokine signaling.
Collapse
Affiliation(s)
- Marcas M Bamman
- Department of Cell, Developmental, and Integrative Biology, University of Alabama at Birmingham, Birmingham, Alabama 35294.,UAB Center for Exercise Medicine, University of Alabama at Birmingham, Birmingham, Alabama 35205.,Geriatric Research, Education, and Clinical Center, Veterans' Affairs Medical Center, Birmingham, Alabama 35233
| | - Brandon M Roberts
- Department of Cell, Developmental, and Integrative Biology, University of Alabama at Birmingham, Birmingham, Alabama 35294.,UAB Center for Exercise Medicine, University of Alabama at Birmingham, Birmingham, Alabama 35205
| | - Gregory R Adams
- Department of Physiology and Biophysics, University of California Irvine, Irvine, California 92617
| |
Collapse
|
20
|
Ato S, Makanae Y, Kido K, Sase K, Yoshii N, Fujita S. The effect of different acute muscle contraction regimens on the expression of muscle proteolytic signaling proteins and genes. Physiol Rep 2018; 5:5/15/e13364. [PMID: 28778992 PMCID: PMC5555890 DOI: 10.14814/phy2.13364] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2017] [Revised: 06/27/2017] [Accepted: 06/28/2017] [Indexed: 01/07/2023] Open
Abstract
Previous studies have reported that different modes of muscle contraction (i.e., eccentric or concentric contraction) with similar contraction times can affect muscle proteolytic responses. However, the effect of different contraction modes on muscle proteolytic response under the same force-time integral (FTI: contraction force × time) has not been investigated. The purpose of this study was to investigate the effect of different contraction modes, with the same FTI, on acute proteolytic signaling responses. Eleven-week-old male Sprague-Dawley rats were randomly assigned to eccentric (EC), concentric (CC), or isometric contraction (IC) groups. Different modes of muscle contraction were performed on the right gastrocnemius muscle using electrical stimulation, with the left muscle acting as a control. In order to apply an equivalent FTI, the number of stimulation sets was modified between the groups. Muscle samples were taken immediately and three hours after exercise. Phosphorylation of FoxO3a at Ser253 was significantly increased immediately after exercise compared to controls irrespective of contraction mode. The mRNA levels of the ubiquitin ligases, MuRF1, and MAFbx mRNA were unchanged by contraction mode or time. Phosphorylation of ULK1 at Ser317 (positive regulatory site) and Ser757 (negative regulatory site) was significantly increased compared to controls, immediately or 3 h after exercise, in all contraction modes. The autophagy markers (LC3B-II/I ratio and p62 expression) were unchanged, regardless of contraction mode. These data suggest that differences in contraction mode during resistance exercise with a constant FTI, are not factors in regulating proteolytic signaling in the early phase of skeletal muscle contraction.
Collapse
Affiliation(s)
- Satoru Ato
- Faculty of Sport and Health Science, Ritsumeikan University, Kusatsu, Shiga, Japan
| | - Yuhei Makanae
- Faculty of Sport and Health Science, Ritsumeikan University, Kusatsu, Shiga, Japan
| | - Kohei Kido
- Faculty of Sport and Health Science, Ritsumeikan University, Kusatsu, Shiga, Japan
| | - Kohei Sase
- Faculty of Sport and Health Science, Ritsumeikan University, Kusatsu, Shiga, Japan
| | - Naomi Yoshii
- Faculty of Sport and Health Science, Ritsumeikan University, Kusatsu, Shiga, Japan
| | - Satoshi Fujita
- Faculty of Sport and Health Science, Ritsumeikan University, Kusatsu, Shiga, Japan
| |
Collapse
|
21
|
Mosole S, Zampieri S, Furlan S, Carraro U, Löefler S, Kern H, Volpe P, Nori A. Effects of Electrical Stimulation on Skeletal Muscle of Old Sedentary People. Gerontol Geriatr Med 2018; 4:2333721418768998. [PMID: 29662923 PMCID: PMC5896842 DOI: 10.1177/2333721418768998] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2017] [Revised: 01/25/2018] [Accepted: 02/08/2018] [Indexed: 01/10/2023] Open
Abstract
Physical activity plays an important role in preventing muscle atrophy and chronic diseases in adults and in the elderly. Calcium (Ca2+) cycling and activation of specific molecular pathways are essential in contraction-induced muscle adaptation. This study attains human muscle sections and total homogenates prepared from biopsies obtained before (control) and after 9 weeks of training by electrical stimulation (ES) on a group of volunteers. The aim of the study was to investigate about the molecular mechanisms that support functional muscle improvement by ES. Evidences of kinase/phosphatase pathways activation after ES were obtained. Moreover, expression of Sarcalumenin, Calsequestrin and sarco/endoplasmic reticulum Ca2+-ATPase (Serca) isoforms was regulated by training. In conclusion, this work shows that neuromuscular ES applied to vastus lateralis muscle of sedentary seniors combines fiber remodeling with activation of Ca2+-Calmodulin molecular pathways and modulation of key Ca2+-handling proteins.
Collapse
Affiliation(s)
- Simone Mosole
- University of Padova, Italy.,Ludwig Boltzmann Institute of Electrical Stimulation and Physical Rehabilitation, Vienna, Austria
| | - Sandra Zampieri
- University of Padova, Italy.,Ludwig Boltzmann Institute of Electrical Stimulation and Physical Rehabilitation, Vienna, Austria
| | - Sandra Furlan
- Institute of Neuroscience Consiglio Nazionale delle Ricerche, Padova, Italy
| | - Ugo Carraro
- IRRCS Fondazione Ospedale San Camillo, Venice, Italy
| | - Stefan Löefler
- Ludwig Boltzmann Institute of Electrical Stimulation and Physical Rehabilitation, Vienna, Austria
| | - Helmut Kern
- Ludwig Boltzmann Institute of Electrical Stimulation and Physical Rehabilitation, Vienna, Austria.,Institute of Physical Medicine and Rehabilitation, St. Pölten, Austria
| | | | | |
Collapse
|
22
|
Vigotsky AD, Halperin I, Lehman GJ, Trajano GS, Vieira TM. Interpreting Signal Amplitudes in Surface Electromyography Studies in Sport and Rehabilitation Sciences. Front Physiol 2018; 8:985. [PMID: 29354060 PMCID: PMC5758546 DOI: 10.3389/fphys.2017.00985] [Citation(s) in RCA: 215] [Impact Index Per Article: 35.8] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2017] [Accepted: 11/17/2017] [Indexed: 12/31/2022] Open
Abstract
Surface electromyography (sEMG) is a popular research tool in sport and rehabilitation sciences. Common study designs include the comparison of sEMG amplitudes collected from different muscles as participants perform various exercises and techniques under different loads. Based on such comparisons, researchers attempt to draw conclusions concerning the neuro- and electrophysiological underpinning of force production and hypothesize about possible longitudinal adaptations, such as strength and hypertrophy. However, such conclusions are frequently unsubstantiated and unwarranted. Hence, the goal of this review is to discuss what can and cannot be inferred from comparative research designs as it pertains to both the acute and longitudinal outcomes. General methodological recommendations are made, gaps in the literature are identified, and lines for future research to help improve the applicability of sEMG are suggested.
Collapse
Affiliation(s)
- Andrew D Vigotsky
- Department of Biomedical Engineering, Northwestern University, Evanston, IL, United States
| | - Israel Halperin
- Physiology Discipline, Australian Institute of Sport, Canberra, ACT, Australia.,Centre for Exercise and Sport Science Research, School of Medical and Health Sciences, Edith Cowan University, Joondalup, WA, Australia
| | | | - Gabriel S Trajano
- School of Exercise and Nutrition Sciences, Queensland University of Technology, Brisbane, QLD, Australia.,Institute of Health and Biomedical Innovation, Queensland University of Technology, Brisbane, QLD, Australia
| | - Taian M Vieira
- Laboratory for Engineering of the Neuromuscular System, Department of Electronics and Telecommunications, Politecnico di Torino, Turin, Italy
| |
Collapse
|
23
|
Miller BF, Hamilton KL, Majeed ZR, Abshire SM, Confides AL, Hayek AM, Hunt ER, Shipman P, Peelor FF, Butterfield TA, Dupont‐Versteegden EE. Enhanced skeletal muscle regrowth and remodelling in massaged and contralateral non-massaged hindlimb. J Physiol 2018; 596:83-103. [PMID: 29090454 PMCID: PMC5746529 DOI: 10.1113/jp275089] [Citation(s) in RCA: 49] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2017] [Accepted: 10/16/2017] [Indexed: 12/21/2022] Open
Abstract
KEY POINTS Muscle fibre cross sectional area is enhanced with massage in the form of cyclic compressive loading during regrowth after atrophy. Massage enhances protein synthesis of the myofibrillar and cytosolic, but not the mitochondrial fraction, in muscle during regrowth. Focal adhesion kinase activation and satellite cell number are elevated in muscles undergoing massage during regrowth. Muscle fibre cross sectional area and protein synthesis of the myofibrillar fraction, but not DNA synthesis, are elevated in muscle of the contralateral non-massaged limb. Massage in the form of cyclic compressive loading is a potential anabolic intervention during muscle regrowth after atrophy. ABSTRACT Massage, in the form of cyclic compressive loading (CCL), is associated with multiple health benefits, but its potential anabolic effect on atrophied muscle has not been investigated. We hypothesized that the mechanical activity associated with CCL induces an anabolic effect in skeletal muscle undergoing regrowth after a period of atrophy. Fischer-Brown Norway rats at 10 months of age were hindlimb unloaded for a period of 2 weeks. The rats were then allowed reambulation with CCL applied at a 4.5 N load at 0.5 Hz frequency for 30 min every other day for four bouts during a regrowth period of 8 days. Muscle fibre cross sectional area was enhanced by 18% with massage during regrowth compared to reloading alone, and this was accompanied by elevated myofibrillar and cytosolic protein as well as DNA synthesis. Focal adhesion kinase phosphorylation indicated that CCL increased mechanical stimulation, while a higher number of Pax7+ cells likely explains the elevated DNA synthesis. Surprisingly, the contralateral non-massaged limb exhibited a comparable 17% higher muscle fibre size compared to reloading alone, and myofibrillar protein synthesis, but not DNA synthesis, was also elevated. We conclude that massage in the form of CCL induces an anabolic response in muscles regrowing after an atrophy-inducing event. We suggest that massage can be used as an intervention to aid in the regrowth of muscle lost during immobilization.
Collapse
Affiliation(s)
- Benjamin F. Miller
- Health and Exercise ScienceColorado State UniversityFort CollinsCO80523‐1582USA
| | - Karyn L. Hamilton
- Health and Exercise ScienceColorado State UniversityFort CollinsCO80523‐1582USA
| | - Zana R. Majeed
- Department of Rehabilitation Sciences, College of Health SciencesUniversity of KentuckyLexingtonKY40536‐0200USA
| | - Sarah M. Abshire
- Department of Rehabilitation Sciences, College of Health SciencesUniversity of KentuckyLexingtonKY40536‐0200USA
- Center for Muscle BiologyUniversity of KentuckyLexingtonKY40536‐0200USA
| | - Amy L. Confides
- Department of Rehabilitation Sciences, College of Health SciencesUniversity of KentuckyLexingtonKY40536‐0200USA
- Center for Muscle BiologyUniversity of KentuckyLexingtonKY40536‐0200USA
| | - Amanda M. Hayek
- Department of Rehabilitation Sciences, College of Health SciencesUniversity of KentuckyLexingtonKY40536‐0200USA
| | - Emily R. Hunt
- Department of Rehabilitation Sciences, College of Health SciencesUniversity of KentuckyLexingtonKY40536‐0200USA
| | - Patrick Shipman
- Department of MathematicsColorado State UniversityFort CollinsCO80523‐1582USA
| | - Frederick F. Peelor
- Health and Exercise ScienceColorado State UniversityFort CollinsCO80523‐1582USA
| | - Timothy A. Butterfield
- Department of Rehabilitation Sciences, College of Health SciencesUniversity of KentuckyLexingtonKY40536‐0200USA
- Center for Muscle BiologyUniversity of KentuckyLexingtonKY40536‐0200USA
| | - Esther E. Dupont‐Versteegden
- Department of Rehabilitation Sciences, College of Health SciencesUniversity of KentuckyLexingtonKY40536‐0200USA
- Center for Muscle BiologyUniversity of KentuckyLexingtonKY40536‐0200USA
| |
Collapse
|