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McKendry J, Stokes T, Mcleod JC, Phillips SM. Resistance Exercise, Aging, Disuse, and Muscle Protein Metabolism. Compr Physiol 2021; 11:2249-2278. [PMID: 34190341 DOI: 10.1002/cphy.c200029] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Skeletal muscle is the organ of locomotion, its optimal function is critical for athletic performance, and is also important for health due to its contribution to resting metabolic rate and as a site for glucose uptake and storage. Numerous endogenous and exogenous factors influence muscle mass. Much of what is currently known regarding muscle protein turnover is owed to the development and use of stable isotope tracers. Skeletal muscle mass is determined by the meal- and contraction-induced alterations of muscle protein synthesis and muscle protein breakdown. Increased loading as resistance training is the most potent nonpharmacological strategy by which skeletal muscle mass can be increased. Conversely, aging (sarcopenia) and muscle disuse lead to the development of anabolic resistance and contribute to the loss of skeletal muscle mass. Nascent omics-based technologies have significantly improved our understanding surrounding the regulation of skeletal muscle mass at the gene, transcript, and protein levels. Despite significant advances surrounding the mechanistic intricacies that underpin changes in skeletal muscle mass, these processes are complex, and more work is certainly needed. In this article, we provide an overview of the importance of skeletal muscle, describe the influence that resistance training, aging, and disuse exert on muscle protein turnover and the molecular regulatory processes that contribute to changes in muscle protein abundance. © 2021 American Physiological Society. Compr Physiol 11:2249-2278, 2021.
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Affiliation(s)
- James McKendry
- Exercise Metabolism Research Group, Department of Kinesiology, McMaster University, Hamilton, Ontario, Canada
| | - Tanner Stokes
- Exercise Metabolism Research Group, Department of Kinesiology, McMaster University, Hamilton, Ontario, Canada
| | - Jonathan C Mcleod
- Exercise Metabolism Research Group, Department of Kinesiology, McMaster University, Hamilton, Ontario, Canada
| | - Stuart M Phillips
- Exercise Metabolism Research Group, Department of Kinesiology, McMaster University, Hamilton, Ontario, Canada
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Acute sprint exercise transcriptome in human skeletal muscle. PLoS One 2019; 14:e0223024. [PMID: 31647849 PMCID: PMC6812755 DOI: 10.1371/journal.pone.0223024] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2019] [Accepted: 09/11/2019] [Indexed: 12/25/2022] Open
Abstract
Aim To examine global gene expression response to profound metabolic and hormonal stress induced by acute sprint exercise. Methods Healthy men and women (n = 14) performed three all-out cycle sprints interspersed by 20 min recovery. Muscle biopsies were obtained before the first, and 2h and 20 min after last sprint. Microarray analysis was performed to analyse acute gene expression response and repeated blood samples were obtained. Results In skeletal muscle, a set of immediate early genes, FOS, NR4A3, MAFF, EGR1, JUNB were markedly upregulated after sprint exercise. Gene ontology analysis from 879 differentially expressed genes revealed predicted activation of various upstream regulators and downstream biofunctions. Gene signatures predicted an enhanced turnover of skeletal muscle mass after sprint exercise and some novel induced genes such as WNT9A, FZD7 and KLHL40 were presented. A substantial increase in circulating free fatty acids (FFA) was noted after sprint exercise, in parallel with upregulation of PGC-1A and the downstream gene PERM1 and gene signatures predicting enhanced lipid turnover. Increase in growth hormone and insulin in blood were related to changes in gene expressions and both hormones were predicted as upstream regulators. Conclusion This is the first study reporting global gene expression in skeletal muscle in response to acute sprint exercise and several novel findings are presented. First, in line with that muscle hypertrophy is not a typical finding after a period of sprint training, both hypertrophy and atrophy factors were regulated. Second, systemic FFA and hormonal and exposure might be involved in the sprint exercise-induced changes in gene expression.
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Böl M, Iyer R, Dittmann J, Garcés-Schröder M, Dietzel A. Investigating the passive mechanical behaviour of skeletal muscle fibres: Micromechanical experiments and Bayesian hierarchical modelling. Acta Biomater 2019; 92:277-289. [PMID: 31077887 DOI: 10.1016/j.actbio.2019.05.015] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2019] [Revised: 04/24/2019] [Accepted: 05/06/2019] [Indexed: 02/06/2023]
Abstract
Characterisation of the skeletal muscle's passive properties is a challenging task since its structure is dominated by a highly complex and hierarchical arrangement of fibrous components at different scales. The present work focuses on the micromechanical characterisation of skeletal muscle fibres, which consist of myofibrils, by realising three different deformation states, namely, axial tension, axial compression, and transversal compression. To the best of the authors' knowledge, the present study provides a novel comprehensive data set representing of different deformation states. These data allow for a better understanding of muscle fibre load transfer mechanisms and can be used for meaningful modelling approaches. As the present study shows, axial tension and compression experiments reveal a strong tension-compression asymmetry at fibre level. In comparison to the tissue level, this asymmetric behaviour is more pronounced at the fibre scale, elucidating the load transfer mechanism in muscle tissue and aiding in the development of future modelling strategies. Further, a Bayesian hierarchical modelling approach was used to consider the experimental fluctuations in a parameter identification scheme, leading to more comprehensive parameter distributions that reflect the entire observed experimental uncertainty. STATEMENT OF SIGNIFICANCE: This article examines for the first time the mechanical properties of skeletal muscle fibres under axial tension, axial compression, and transversal compression, leading to a highly comprehensive data set. Moreover, a Bayesian hierarchical modelling concept is presented to identify model parameters in a broad way. The results of the deformation states allow a new and comprehensive understanding of muscle fibres' load transfer mechanisms; one example is the effect of tension-compression asymmetry. On the one hand, the results of this study contribute to the understanding of muscle mechanics and thus to the muscle's functional understanding during daily activity. On the other hand, they are relevant in the fields of skeletal muscle multiscale, constitutive modelling.
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Affiliation(s)
- Markus Böl
- Institute of Solid Mechanics, Technische Universität Braunschweig, Braunschweig D-38106, Germany.
| | - Rahul Iyer
- Institute of Solid Mechanics, Technische Universität Braunschweig, Braunschweig D-38106, Germany
| | - Johannes Dittmann
- Institute of Solid Mechanics, Technische Universität Braunschweig, Braunschweig D-38106, Germany
| | - Mayra Garcés-Schröder
- Institute of Micro Technology, Technische Universität Braunschweig, Braunschweig D-38124, Germany
| | - Andreas Dietzel
- Institute of Micro Technology, Technische Universität Braunschweig, Braunschweig D-38124, Germany
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Mey JT, Solomon TPJ, Kirwan JP, Haus JM. Skeletal muscle Nur77 and NOR1 insulin responsiveness is blunted in obesity and type 2 diabetes but improved after exercise training. Physiol Rep 2019; 7:e14042. [PMID: 30912283 PMCID: PMC6434071 DOI: 10.14814/phy2.14042] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2019] [Revised: 03/07/2019] [Accepted: 03/07/2019] [Indexed: 02/07/2023] Open
Abstract
Obesity and type 2 diabetes (T2DM) are characterized by a blunted metabolic response to insulin, and strongly manifests in skeletal muscle insulin resistance. The orphan nuclear receptors, Nur77 and NOR1, regulate insulin-stimulated nutrient metabolism where Nur77 and NOR1 gene expression is increased with acute aerobic exercise and acute insulin stimulation. Whether Nur77 or NOR1 are associated with the insulin-sensitizing effects of chronic aerobic exercise training has yet to be elucidated. Fourteen lean healthy controls (LHC), 12 obese (OB), and 10 T2DM individuals (T2DM) underwent hyperinsulinemic-euglycemic clamps with skeletal muscle biopsies. Muscle was analyzed for Nur77 and NOR1 gene and protein expression at basal and insulin-stimulated conditions. Furthermore, a subcohort of 18 participants (OB, n = 12; T2DM, n = 6) underwent a 12-week aerobic exercise intervention (85% HRmax , 60 min/day, 5 days/week). In response to insulin infusion, LHC increased protein expression of Nur77 (8.7 ± 3.2-fold) and NOR1 (3.6 ± 1.1-fold), whereas OB and T2DM remained unaffected. Clamp-derived glucose disposal rates correlated with Nur77 (r2 = 0.14) and NOR1 (r2 = 0.12) protein expression responses to insulin, whereas age (Nur77: r2 = 0.22; NOR1: r2 = 0.25) and BMI (Nur77: r2 = 0.22; NOR1: r2 = 0.42) showed inverse correlations, corroborating preclinical data. In the intervention cohort, exercise improved Nur77 protein expression in response to insulin (PRE: -1.2 ± 0.3%, POST: 6.2 ± 1.5%). Also, insulin treatment of primary human skeletal muscle cells increased Nur77 and NOR1 protein. These findings highlight the multifactorial nature of insulin resistance in human obesity and T2DM. Understanding the regulation of Nur77 and NOR1 in skeletal muscle and other insulin-sensitive tissues will create opportunities to advance therapies for T2DM.
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MESH Headings
- Adult
- Aged
- Case-Control Studies
- Cells, Cultured
- Chicago
- Cross-Sectional Studies
- Diabetes Mellitus, Type 2/blood
- Diabetes Mellitus, Type 2/diagnosis
- Diabetes Mellitus, Type 2/physiopathology
- Diabetes Mellitus, Type 2/therapy
- Exercise Therapy
- Female
- Humans
- Insulin Resistance
- Longitudinal Studies
- Male
- Membrane Transport Proteins/genetics
- Membrane Transport Proteins/metabolism
- Middle Aged
- Muscle, Skeletal/metabolism
- Muscle, Skeletal/physiopathology
- Myoblasts, Skeletal/metabolism
- Nuclear Receptor Subfamily 4, Group A, Member 1/genetics
- Nuclear Receptor Subfamily 4, Group A, Member 1/metabolism
- Obesity/blood
- Obesity/diagnosis
- Obesity/physiopathology
- Obesity/therapy
- Ohio
- Signal Transduction
- Time Factors
- Treatment Outcome
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Affiliation(s)
- Jacob T. Mey
- Department of Kinesiology and NutritionUniversity of Illinois ChicagoChicagoIllinois
| | - Thomas P. J. Solomon
- School of Sport, Exercise, and Rehabilitation SciencesUniversity of BirminghamBirminghamUnited Kingdom
| | - John P. Kirwan
- Metabolic Translational Research CenterEndocrinology & Metabolism InstituteCleveland ClinicClevelandOhio
- Integrative Physiology and Molecular Medicine LaboratoryPennington Biomedical Research CenterBaton RougeLouisiana
| | - Jacob M. Haus
- Department of Kinesiology and NutritionUniversity of Illinois ChicagoChicagoIllinois
- School of KinesiologyUniversity of MichiganAnn ArborMichigan
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McGlory C, Devries MC, Phillips SM. Skeletal muscle and resistance exercise training; the role of protein synthesis in recovery and remodeling. J Appl Physiol (1985) 2016; 122:541-548. [PMID: 27742803 DOI: 10.1152/japplphysiol.00613.2016] [Citation(s) in RCA: 77] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2016] [Revised: 10/04/2016] [Accepted: 10/05/2016] [Indexed: 12/22/2022] Open
Abstract
Exercise results in the rapid remodeling of skeletal muscle. This process is underpinned by acute and chronic changes in both gene and protein synthesis. In this short review we provide a brief summary of our current understanding regarding how exercise influences these processes as well as the subsequent impact on muscle protein turnover and resultant shift in muscle phenotype. We explore concepts of ribosomal biogenesis and the potential role of increased translational capacity vs. translational efficiency in contributing to muscular hypertrophy. We also examine whether high-intensity sprinting-type exercise promotes changes in protein turnover that lead to hypertrophy or merely a change in mitochondrial content. Finally, we propose novel areas for future study that will fill existing knowledge gaps in the fields of translational research and exercise science.
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Affiliation(s)
- Chris McGlory
- Department of Kinesiology, McMaster University, Ontario, Canada
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6
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Välimäki IA, Vuorimaa T, Ahotupa M, Vasankari TJ. Strenuous physical exercise accelerates the lipid peroxide clearing transport by HDL. Eur J Appl Physiol 2016; 116:1683-91. [DOI: 10.1007/s00421-016-3422-y] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2015] [Accepted: 06/26/2016] [Indexed: 01/14/2023]
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7
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Pan JH, Kim JH, Kim HM, Lee ES, Shin DH, Kim S, Shin M, Kim SH, Lee JH, Kim YJ. Acetic acid enhances endurance capacity of exercise-trained mice by increasing skeletal muscle oxidative properties. Biosci Biotechnol Biochem 2015; 79:1535-41. [DOI: 10.1080/09168451.2015.1034652] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
Abstract
Acetic acid has been shown to promote glycogen replenishment in skeletal muscle during exercise training. In this study, we investigated the effects of acetic acid on endurance capacity and muscle oxidative metabolism in the exercise training using in vivo mice model. In exercised mice, acetic acid induced a significant increase in endurance capacity accompanying a reduction in visceral adipose depots. Serum levels of non-esterified fatty acid and urea nitrogen were significantly lower in acetic acid-fed mice in the exercised mice. Importantly, in the mice, acetic acid significantly increased the muscle expression of key enzymes involved in fatty acid oxidation and glycolytic-to-oxidative fiber-type transformation. Taken together, these findings suggest that acetic acid improves endurance exercise capacity by promoting muscle oxidative properties, in part through the AMPK-mediated fatty acid oxidation and provide an important basis for the application of acetic acid as a major component of novel ergogenic aids.
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Affiliation(s)
- Jeong Hoon Pan
- Department of Food and Biotechnology, Korea University, Sejong, Republic of Korea
| | - Jun Ho Kim
- Department of Food and Biotechnology, Korea University, Sejong, Republic of Korea
| | - Hyung Min Kim
- Department of Food and Biotechnology, Korea University, Sejong, Republic of Korea
| | - Eui Seop Lee
- Department of Food and Biotechnology, Korea University, Sejong, Republic of Korea
| | - Dong-Hoon Shin
- Department of Food and Biotechnology, Korea University, Sejong, Republic of Korea
| | - Seongpil Kim
- R&D Center, Daesang Corp., Icheon, Republic of Korea
| | | | - Sang Ho Kim
- School of Global Sport Studies, Korea University, Sejong, Republic of Korea
| | - Jin Hyup Lee
- Department of Food and Biotechnology, Korea University, Sejong, Republic of Korea
| | - Young Jun Kim
- Department of Food and Biotechnology, Korea University, Sejong, Republic of Korea
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Assis L, Yamashita F, Magri AMP, Fernandes KR, Yamauchi L, Renno ACM. Effect of low-level laser therapy (808 nm) on skeletal muscle after endurance exercise training in rats. Braz J Phys Ther 2015; 19:457-65. [PMID: 26647747 PMCID: PMC4668339 DOI: 10.1590/bjpt-rbf.2014.0113] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/24/2014] [Accepted: 05/28/2015] [Indexed: 11/29/2022] Open
Abstract
BACKGROUND: Low-level laser therapy (LLLT) has been demonstrated to be effective in
optimizing skeletal muscle performance in animal experiments and in clinical
trials. However, little is known about the effects of LLLT on muscle recovery
after endurance training. OBJECTIVE: This study evaluates the effects of low-level laser therapy (LLLT) applied after
an endurance training protocol on biochemical markers and morphology of skeletal
muscle in rats. METHOD: Wistar rats were divided into control group (CG), trained group (TG), and trained
and laser irradiated group (TLG). The endurance training was performed on a
treadmill, 1 h/day, 5 days/wk, for 8 wk at 60% of the maximal speed reached during
the maximal effort test (Tmax) and laser irradiation was applied after training.
RESULTS: Both trained groups showed significant increase in speed compared to the CG. The
TLG demonstrated a significantly reduced lactate level, increased tibialis
anterior (TA) fiber cross-section area, and decreased TA fiber density. Myogenin
expression was higher in soleus and TA muscles in both trained groups. In
addition, LLLT produced myogenin downregulation in the TA muscle of trained
animals. CONCLUSION: These results suggest that LLLT could be an effective therapeutic approach for
stimulating recovery during an endurance exercise protocol.
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Affiliation(s)
- Livia Assis
- Departamento de Biociências, Universidade Federal de São Paulo, Santos, SP, Brazil
| | - Fernanda Yamashita
- Departamento de Biociências, Universidade Federal de São Paulo, Santos, SP, Brazil
| | - Angela M P Magri
- Departamento de Biociências, Universidade Federal de São Paulo, Santos, SP, Brazil
| | - Kelly R Fernandes
- Departamento de Biociências, Universidade Federal de São Paulo, Santos, SP, Brazil
| | - Liria Yamauchi
- Departamento de Ciências do Movimento Humano, Universidade Federal de São Paulo, Santos, SP, Brazil
| | - Ana C M Renno
- Departamento de Biociências, Universidade Federal de São Paulo, Santos, SP, Brazil
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9
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Interference between concurrent resistance and endurance exercise: molecular bases and the role of individual training variables. Sports Med 2014; 44:743-62. [PMID: 24728927 DOI: 10.1007/s40279-014-0162-1] [Citation(s) in RCA: 179] [Impact Index Per Article: 17.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Concurrent training is defined as simultaneously incorporating both resistance and endurance exercise within a periodized training regime. Despite the potential additive benefits of combining these divergent exercise modes with regards to disease prevention and athletic performance, current evidence suggests that this approach may attenuate gains in muscle mass, strength, and power compared with undertaking resistance training alone. This has been variously described as the interference effect or concurrent training effect. In recent years, understanding of the molecular mechanisms mediating training adaptation in skeletal muscle has emerged and provided potential mechanistic insight into the concurrent training effect. Although it appears that various molecular signaling responses induced in skeletal muscle by endurance exercise can inhibit pathways regulating protein synthesis and stimulate protein breakdown, human studies to date have not observed such molecular 'interference' following acute concurrent exercise that might explain compromised muscle hypertrophy following concurrent training. However, given the multitude of potential concurrent training variables and the limitations of existing evidence, the potential roles of individual training variables in acute and chronic interference are not fully elucidated. The present review explores current evidence for the molecular basis of the specificity of training adaptation and the concurrent interference phenomenon. Additionally, insights provided by molecular and performance-based concurrent training studies regarding the role of individual training variables (i.e., within-session exercise order, between-mode recovery, endurance training volume, intensity, and modality) in the concurrent interference effect are discussed, along with the limitations of our current understanding of this complex paradigm.
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10
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Agudelo L, Femenía T, Orhan F, Porsmyr-Palmertz M, Goiny M, Martinez-Redondo V, Correia J, Izadi M, Bhat M, Schuppe-Koistinen I, Pettersson A, Ferreira D, Krook A, Barres R, Zierath J, Erhardt S, Lindskog M, Ruas J. Skeletal Muscle PGC-1α1 Modulates Kynurenine Metabolism and Mediates Resilience to Stress-Induced Depression. Cell 2014; 159:33-45. [DOI: 10.1016/j.cell.2014.07.051] [Citation(s) in RCA: 443] [Impact Index Per Article: 44.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2014] [Revised: 06/27/2014] [Accepted: 07/16/2014] [Indexed: 01/17/2023]
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11
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Vitošević B, Ranković J, Mitić NR, Popović L, Ranković Nedin G. PHARMACOLOGICAL EXERCISE MIMETICS IN THERAPY: DELUSION OR FUTURE? ACTA MEDICA MEDIANAE 2013. [DOI: 10.5633/amm.2013.0411] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
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12
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Egan B, O’Connor PL, Zierath JR, O’Gorman DJ. Time course analysis reveals gene-specific transcript and protein kinetics of adaptation to short-term aerobic exercise training in human skeletal muscle. PLoS One 2013; 8:e74098. [PMID: 24069271 PMCID: PMC3771935 DOI: 10.1371/journal.pone.0074098] [Citation(s) in RCA: 91] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2013] [Accepted: 07/29/2013] [Indexed: 11/18/2022] Open
Abstract
Repeated bouts of episodic myofibrillar contraction associated with exercise training are potent stimuli for physiological adaptation. However, the time course of adaptation and the continuity between alterations in mRNA expression and protein content are not well described in human skeletal muscle. Eight healthy, sedentary males cycled for 60 min at 80% of peak oxygen consumption (VO2peak) each day for fourteen consecutive days, resulting in an increase in VO2peak of 17.5±3.8%. Skeletal muscle biopsies were taken at baseline, and on the morning following (+16 h after exercise) the first, third, seventh, tenth and fourteenth training sessions. Markers of mitochondrial adaptation (Cyt c and COXIV expression, and citrate synthase activity) were increased within the first week of training, but the mtDNA/nDNA ratio was unchanged by two weeks of training. Accumulation of PGC-1α and ERRα protein during training suggests a regulatory role for these factors in adaptations of mitochondrial and metabolic gene expression. A subset of genes were transiently increased after one training session, but returned to baseline levels thereafter, which is supportive of the concept of transcriptional capacity being particularly sensitive to the onset of a new level of contractile activity. Thus, gene-specific temporal patterns of induction of mRNA expression and protein content are described. Our results illustrate the phenomenology of skeletal muscle plasticity and support the notion that transcript level adjustments, coupled to accumulation of encoded protein, underlie the modulation of skeletal muscle metabolism and phenotype by regular exercise.
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Affiliation(s)
- Brendan Egan
- Institute for Sport and Health, School of Public Health, Physiotherapy, and Population Sciences, University College Dublin, Dublin, Ireland
- Department of Molecular Medicine and Surgery, Section of Integrative Physiology, Karolinska Institute, Stockholm, Sweden
| | - Paul L. O’Connor
- School of Health and Human Performance, Dublin City University, Dublin, Ireland
| | - Juleen R. Zierath
- Department of Molecular Medicine and Surgery, Section of Integrative Physiology, Karolinska Institute, Stockholm, Sweden
- Department of Physiology and Pharmacology, Karolinska Institute, Stockholm, Sweden
| | - Donal J. O’Gorman
- School of Health and Human Performance, Dublin City University, Dublin, Ireland
- Centre for Preventive Medicine, Dublin City University, Dublin, Ireland
- * E-mail:
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13
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Busso T, Flück M. A mixed-effects model of the dynamic response of muscle gene transcript expression to endurance exercise. Eur J Appl Physiol 2012. [PMID: 23179205 DOI: 10.1007/s00421-012-2547-x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Altered expression of a broad range of gene transcripts after exercise reflects the specific adjustment of skeletal muscle makeup to endurance training. Towards a quantitative understanding of this molecular regulation, we aimed to build a mixed-effects model of the dynamics of co-related transcript responses to exercise. It was built on the assumption that transcript levels after exercise varied because of changes in the balance between transcript synthesis and degradation. It was applied to microarray data of 231 gene transcripts in vastus lateralis muscle of six subjects 1, 8 and 24 h after endurance exercise and 6-week training on a stationary bicycle. Cluster analysis was used to select groups of transcripts having highest co-correlation of their expression (r > 0.70): Group 1 comprised 45 transcripts including factors defining the oxidative and contractile phenotype and Group 2 included 39 transcripts mainly defined by factors found at the cell periphery and the extracellular space. Data from six subjects were pooled to filter experimental noise. The model fitted satisfactorily the responses of Group 1 (r (2) = 0.62 before and 0.85 after training, P < 0.001) and Group 2 (r (2) = 0.75 and 0.79, P < 0.001). Predicted variation in transcription rate induced by exercise yielded a difference in amplitude and time-to-peak response of gene transcripts between the two groups before training and with training in Group 2. The findings illustrate that a mixed-effects model of transcript responses to exercise is suitable to explore the regulation of muscle plasticity by training at the transcriptional level and indicate critical experiments needed to consolidate model parameters empirically.
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Affiliation(s)
- Thierry Busso
- Laboratoire de Physiologie de l'Exercice, Université de Lyon, Saint-Etienne, France.
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14
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Phillips SM, Van Loon LJC. Dietary protein for athletes: from requirements to optimum adaptation. J Sports Sci 2012; 29 Suppl 1:S29-38. [PMID: 22150425 DOI: 10.1080/02640414.2011.619204] [Citation(s) in RCA: 231] [Impact Index Per Article: 19.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
Opinion on the role of protein in promoting athletic performance is divided along the lines of how much aerobic-based versus resistance-based activity the athlete undertakes. Athletes seeking to gain muscle mass and strength are likely to consume higher amounts of dietary protein than their endurance-trained counterparts. The main belief behind the large quantities of dietary protein consumption in resistance-trained athletes is that it is needed to generate more muscle protein. Athletes may require protein for more than just alleviation of the risk for deficiency, inherent in the dietary guidelines, but also to aid in an elevated level of functioning and possibly adaptation to the exercise stimulus. It does appear, however, that there is a good rationale for recommending to athletes protein intakes that are higher than the RDA. Our consensus opinion is that leucine, and possibly the other branched-chain amino acids, occupy a position of prominence in stimulating muscle protein synthesis; that protein intakes in the range of 1.3-1.8 g · kg(-1) · day(-1) consumed as 3-4 isonitrogenous meals will maximize muscle protein synthesis. These recommendations may also be dependent on training status: experienced athletes would require less, while more protein should be consumed during periods of high frequency/intensity training. Elevated protein consumption, as high as 1.8-2.0 g · kg(-1) · day(-1) depending on the caloric deficit, may be advantageous in preventing lean mass losses during periods of energy restriction to promote fat loss.
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Affiliation(s)
- Stuart M Phillips
- Department of Kinesiology, Exercise Metabolism Research Group, McMaster University, Hamilton, Ontario, Canada.
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15
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Narkar VA, Downes M, Yu RT, Embler E, Wang YX, Banayo E, Mihaylova MM, Nelson MC, Zou Y, Juguilon H, Kang H, Shaw RJ, Evans RM. AMPK and PPARdelta agonists are exercise mimetics. Cell 2008; 134:405-15. [PMID: 18674809 PMCID: PMC2706130 DOI: 10.1016/j.cell.2008.06.051] [Citation(s) in RCA: 1179] [Impact Index Per Article: 73.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2007] [Revised: 04/23/2008] [Accepted: 06/20/2008] [Indexed: 10/21/2022]
Abstract
The benefits of endurance exercise on general health make it desirable to identify orally active agents that would mimic or potentiate the effects of exercise to treat metabolic diseases. Although certain natural compounds, such as reseveratrol, have endurance-enhancing activities, their exact metabolic targets remain elusive. We therefore tested the effect of pathway-specific drugs on endurance capacities of mice in a treadmill running test. We found that PPARbeta/delta agonist and exercise training synergistically increase oxidative myofibers and running endurance in adult mice. Because training activates AMPK and PGC1alpha, we then tested whether the orally active AMPK agonist AICAR might be sufficient to overcome the exercise requirement. Unexpectedly, even in sedentary mice, 4 weeks of AICAR treatment alone induced metabolic genes and enhanced running endurance by 44%. These results demonstrate that AMPK-PPARdelta pathway can be targeted by orally active drugs to enhance training adaptation or even to increase endurance without exercise.
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Affiliation(s)
- Vihang A Narkar
- Gene Expression Laboratory, Salk Institute, La Jolla, CA 92037, USA
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Tarnopolsky MA, Safdar A. The potential benefits of creatine and conjugated linoleic acid as adjuncts to resistance training in older adults. Appl Physiol Nutr Metab 2008; 33:213-27. [PMID: 18347674 DOI: 10.1139/h07-142] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Human aging is associated with a significant reduction in muscle mass (sarcopenia) resulting in muscle weakness and functional limitations in the elderly. Sarcopenia has been associated with mitochondrial dysfunction and the accumulation of mtDNA deletions. Resistance training increases muscle strength and size and can increase mitochondrial capacity and decrease oxidative stress in older adults. Creatine monohydrate (CrM) and conjugated linoleic acid (CLA) have biological effects that could enhance some of the beneficial effects of resistance training in older adults (i.e., up arrow fat-free mass, down arrow total body fat). We have completed two resistance-training studies with CrM alone and CrM+CLA supplementation in older adults to evaluate the independent effects of exercise and dietary supplements, as well as their interactive effects. Our studies, and several others, have found that CrM enhanced the resistance exercise mediated gains in fat-free mass and strength. More recently, we found that the addition of CLA also lead to a significant reduction of body fat after six months of resistance training in older adults. Older adults have fewer wild-type mtDNA copies and higher amounts of mtDNA deletions as compared with younger adults in mature skeletal muscle; however, these deletions are not seen in the satellite cell-derived myoblast cultures. These findings, and the fact that mtDNA deletions are lower and wild-type mtDNA copy number is higher after resistance training in older adults, suggests that activation of satellite cells secondary to resistance exercise-induced muscle damage can dilute or "shift" the proportion of mtDNA genotype towards that of a younger adult. Recent evidence suggests that CrM supplementation in combination with strength training can enhance satellite cell activation and total myonuclei number per muscle fiber in young men. Future studies are required to determine whether the mitochondrial adaptations to resistance exercise in older adults are further enhanced with CrM supplementation and whether this is due to increased recruitment of satellite cells. It will also be important to determine whether these changes are maintained over a longer time period.
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Affiliation(s)
- Mark A Tarnopolsky
- Department of Pediatrics and Medicine, McMaster University, HSC-2H26, 1200 Main St. W., Hamilton, ON L8N 3Z5, Canada.
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Gibala MJ, Little JP, van Essen M, Wilkin GP, Burgomaster KA, Safdar A, Raha S, Tarnopolsky MA. Short-term sprint interval versus traditional endurance training: similar initial adaptations in human skeletal muscle and exercise performance. J Physiol 2006; 575:901-11. [PMID: 16825308 PMCID: PMC1995688 DOI: 10.1113/jphysiol.2006.112094] [Citation(s) in RCA: 647] [Impact Index Per Article: 35.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2006] [Accepted: 06/29/2006] [Indexed: 12/14/2022] Open
Abstract
Brief, intense exercise training may induce metabolic and performance adaptations comparable to traditional endurance training. However, no study has directly compared these diverse training strategies in a standardized manner. We therefore examined changes in exercise capacity and molecular and cellular adaptations in skeletal muscle after low volume sprint-interval training (SIT) and high volume endurance training (ET). Sixteen active men (21 +/- 1 years, ) were assigned to a SIT or ET group (n = 8 each) and performed six training sessions over 14 days. Each session consisted of either four to six repeats of 30 s 'all out' cycling at approximately 250% with 4 min recovery (SIT) or 90-120 min continuous cycling at approximately 65% (ET). Training time commitment over 2 weeks was approximately 2.5 h for SIT and approximately 10.5 h for ET, and total training volume was approximately 90% lower for SIT versus ET ( approximately 630 versus approximately 6500 kJ). Training decreased the time required to complete 50 and 750 kJ cycling time trials, with no difference between groups (main effects, P = 0.05). Biopsy samples obtained before and after training revealed similar increases in muscle oxidative capacity, as reflected by the maximal activity of cytochrome c oxidase (COX) and COX subunits II and IV protein content (main effects, P = 0.05), but COX II and IV mRNAs were unchanged. Training-induced increases in muscle buffering capacity and glycogen content were also similar between groups (main effects, P = 0.05). Given the large difference in training volume, these data demonstrate that SIT is a time-efficient strategy to induce rapid adaptations in skeletal muscle and exercise performance that are comparable to ET in young active men.
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Affiliation(s)
- Martin J Gibala
- Department of Kinesiology IWC AB122, McMaster University, 1280 Main Street West, Hamilton, Ontario, L8S 4K1, Canada.
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