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Roberts MD, McCarthy JJ, Hornberger TA, Phillips SM, Mackey AL, Nader GA, Boppart MD, Kavazis AN, Reidy PT, Ogasawara R, Libardi CA, Ugrinowitsch C, Booth FW, Esser KA. Mechanisms of mechanical overload-induced skeletal muscle hypertrophy: current understanding and future directions. Physiol Rev 2023; 103:2679-2757. [PMID: 37382939 PMCID: PMC10625844 DOI: 10.1152/physrev.00039.2022] [Citation(s) in RCA: 39] [Impact Index Per Article: 39.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2023] [Revised: 06/12/2023] [Accepted: 06/21/2023] [Indexed: 06/30/2023] Open
Abstract
Mechanisms underlying mechanical overload-induced skeletal muscle hypertrophy have been extensively researched since the landmark report by Morpurgo (1897) of "work-induced hypertrophy" in dogs that were treadmill trained. Much of the preclinical rodent and human resistance training research to date supports that involved mechanisms include enhanced mammalian/mechanistic target of rapamycin complex 1 (mTORC1) signaling, an expansion in translational capacity through ribosome biogenesis, increased satellite cell abundance and myonuclear accretion, and postexercise elevations in muscle protein synthesis rates. However, several lines of past and emerging evidence suggest that additional mechanisms that feed into or are independent of these processes are also involved. This review first provides a historical account of how mechanistic research into skeletal muscle hypertrophy has progressed. A comprehensive list of mechanisms associated with skeletal muscle hypertrophy is then outlined, and areas of disagreement involving these mechanisms are presented. Finally, future research directions involving many of the discussed mechanisms are proposed.
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Affiliation(s)
- Michael D Roberts
- School of Kinesiology, Auburn University, Auburn, Alabama, United States
| | - John J McCarthy
- Department of Physiology, College of Medicine, University of Kentucky, Lexington, Kentucky, United States
| | - Troy A Hornberger
- Department of Comparative Biosciences, University of Wisconsin-Madison, Madison, Wisconsin, United States
| | - Stuart M Phillips
- Department of Kinesiology, McMaster University, Hamilton, Ontario, Canada
| | - Abigail L Mackey
- Institute of Sports Medicine Copenhagen, Department of Orthopedic Surgery, Copenhagen University Hospital-Bispebjerg and Frederiksberg, and Department of Clinical Medicine, University of Copenhagen, Copenhagen, Denmark
| | - Gustavo A Nader
- Department of Kinesiology and Huck Institutes of the Life Sciences, The Pennsylvania State University, University Park, Pennsylvania, United States
| | - Marni D Boppart
- Department of Kinesiology and Community Health, University of Illinois at Urbana-Champaign, Urbana, Illinois, United States
| | - Andreas N Kavazis
- School of Kinesiology, Auburn University, Auburn, Alabama, United States
| | - Paul T Reidy
- Department of Kinesiology, Nutrition and Health, Miami University, Oxford, Ohio, United States
| | - Riki Ogasawara
- Healthy Food Science Research Group, Cellular and Molecular Biotechnology Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Japan
| | - Cleiton A Libardi
- MUSCULAB-Laboratory of Neuromuscular Adaptations to Resistance Training, Department of Physical Education, Federal University of São Carlos, São Carlos, Brazil
| | - Carlos Ugrinowitsch
- School of Physical Education and Sport, University of São Paulo, São Paulo, Brazil
| | - Frank W Booth
- Department of Biomedical Sciences, University of Missouri, Columbia, Missouri, United States
| | - Karyn A Esser
- Department of Physiology and Aging, College of Medicine, University of Florida, Gainesville, Florida, United States
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McIntosh MC, Sexton CL, Godwin JS, Ruple BA, Michel JM, Plotkin DL, Ziegenfuss TN, Lopez HL, Smith R, Dwaraka VB, Sharples AP, Dalbo VJ, Mobley CB, Vann CG, Roberts MD. Different Resistance Exercise Loading Paradigms Similarly Affect Skeletal Muscle Gene Expression Patterns of Myostatin-Related Targets and mTORC1 Signaling Markers. Cells 2023; 12:898. [PMID: 36980239 PMCID: PMC10047349 DOI: 10.3390/cells12060898] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2023] [Revised: 03/10/2023] [Accepted: 03/14/2023] [Indexed: 03/17/2023] Open
Abstract
Although transcriptome profiling has been used in several resistance training studies, the associated analytical approaches seldom provide in-depth information on individual genes linked to skeletal muscle hypertrophy. Therefore, a secondary analysis was performed herein on a muscle transcriptomic dataset we previously published involving trained college-aged men (n = 11) performing two resistance exercise bouts in a randomized and crossover fashion. The lower-load bout (30 Fail) consisted of 8 sets of lower body exercises to volitional fatigue using 30% one-repetition maximum (1 RM) loads, whereas the higher-load bout (80 Fail) consisted of the same exercises using 80% 1 RM loads. Vastus lateralis muscle biopsies were collected prior to (PRE), 3 h, and 6 h after each exercise bout, and 58 genes associated with skeletal muscle hypertrophy were manually interrogated from our prior microarray data. Select targets were further interrogated for associated protein expression and phosphorylation induced-signaling events. Although none of the 58 gene targets demonstrated significant bout x time interactions, ~57% (32 genes) showed a significant main effect of time from PRE to 3 h (15↑ and 17↓, p < 0.01), and ~26% (17 genes) showed a significant main effect of time from PRE to 6 h (8↑ and 9↓, p < 0.01). Notably, genes associated with the myostatin (9 genes) and mammalian target of rapamycin complex 1 (mTORC1) (9 genes) signaling pathways were most represented. Compared to mTORC1 signaling mRNAs, more MSTN signaling-related mRNAs (7 of 9) were altered post-exercise, regardless of the bout, and RHEB was the only mTORC1-associated mRNA that was upregulated following exercise. Phosphorylated (phospho-) p70S6K (Thr389) (p = 0.001; PRE to 3 h) and follistatin protein levels (p = 0.021; PRE to 6 h) increased post-exercise, regardless of the bout, whereas phospho-AKT (Thr389), phospho-mTOR (Ser2448), and myostatin protein levels remained unaltered. These data continue to suggest that performing resistance exercise to volitional fatigue, regardless of load selection, elicits similar transient mRNA and signaling responses in skeletal muscle. Moreover, these data provide further evidence that the transcriptional regulation of myostatin signaling is an involved mechanism in response to resistance exercise.
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Affiliation(s)
| | - Casey L. Sexton
- School of Kinesiology, Auburn University, Auburn, AL 36849, USA
| | | | | | - J. Max Michel
- School of Kinesiology, Auburn University, Auburn, AL 36849, USA
| | | | | | | | | | | | - Adam P. Sharples
- Institute for Physical Performance, Norwegian School of Sport Sciences, 0164 Oslo, Norway
| | - Vincent J. Dalbo
- School of Health, Medical and Applied Sciences, Central Queensland University, Rockhampton 4700, Australia
| | | | - Christopher G. Vann
- Duke Molecular Physiology Institute, Duke University School of Medicine, Durham, NC 03824, USA
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Santos HO, Cerqueira HS, Tinsley GM. The Effects of Dietary Supplements, Nutraceutical Agents, and Physical Exercise on Myostatin Levels: Hope or Hype? Metabolites 2022; 12:1146. [PMID: 36422286 PMCID: PMC9695935 DOI: 10.3390/metabo12111146] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2022] [Revised: 11/16/2022] [Accepted: 11/18/2022] [Indexed: 09/12/2024] Open
Abstract
Myostatin, a secreted growth factor belonging to the transforming growth factor β (TGF-β) family, performs a role in hindering muscle growth by inhibiting protein kinase B (Akt) phosphorylation and the associated activation of hypertrophy pathways (e.g., IGF-1/PI3K/Akt/mTOR pathway). In addition to pharmacological agents, some supplements and nutraceutical agents have demonstrated modulatory effects on myostatin levels; however, the clinical magnitude must be appraised with skepticism before translating the mechanistic effects into muscle hypertrophy outcomes. Here, we review the effects of dietary supplements, nutraceutical agents, and physical exercise on myostatin levels, addressing the promise and pitfalls of relevant randomized clinical trials (RCTs) to draw clinical conclusions. RCTs involving both clinical and sports populations were considered, along with wasting muscle disorders (e.g., sarcopenia) and resistance training-induced muscle hypertrophy, irrespective of disease status. Animal models were considered only to expand the mechanisms of action, and observational data were consulted to elucidate potential cutoff values. Collectively, the effects of dietary supplements, nutraceutical agents, and physical exercise on myostatin mRNA expression in skeletal muscle and serum myostatin levels are not uniform, and there may be reductions, increases, or neutral effects. Large amounts of research using resistance protocols shows that supplements or functional foods do not clearly outperform placebo for modulating myostatin levels. Thus, despite some biological hope in using supplements or certain functional foods to decrease myostatin levels, caution must be exercised not to propagate the hope of the food supplement market, select health professionals, and laypeople.
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Affiliation(s)
- Heitor O. Santos
- School of Medicine, Federal University of Uberlandia (UFU), Uberlandia 38408-100, Brazil
| | | | - Grant M. Tinsley
- Department of Kinesiology and Sport Management, Texas Tech University, Lubbock, TX 79409, USA
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Pan J, Purev C, Zhao H, Zhang Z, Wang F, Wendoule N, Qi G, Liu Y, Zhou H. Discovery of exercise-related genes and pathway analysis based on comparative genomes of Mongolian originated Abaga and Wushen horse. Open Life Sci 2022; 17:1269-1281. [PMID: 36249530 PMCID: PMC9518662 DOI: 10.1515/biol-2022-0487] [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: 04/13/2022] [Revised: 07/21/2022] [Accepted: 07/28/2022] [Indexed: 11/17/2022] Open
Abstract
The Mongolian horses have excellent endurance and stress resistance to adapt to the cold and harsh plateau conditions. Intraspecific genetic diversity is mainly embodied in various genetic advantages of different branches of the Mongolian horse. Since people pay progressive attention to the athletic performance of horse, we expect to guide the exercise-oriented breeding of horses through genomics research. We obtained the clean data of 630,535,376,400 bp through the entire genome second-generation sequencing for the whole blood of four Abaga horses and ten Wushen horses. Based on the data analysis of single nucleotide polymorphism, we severally detected that 479 and 943 positively selected genes, particularly exercise related, were mainly enriched on equine chromosome 4 in Abaga horses and Wushen horses, which implied that chromosome 4 may be associated with the evolution of the Mongolian horse and athletic performance. Four hundred and forty genes of positive selection were enriched in 12 exercise-related pathways and narrowed in 21 exercise-related genes in Abaga horse, which were distinguished from Wushen horse. So, we speculated that the Abaga horse may have oriented genes for the motorial mechanism and 21 exercise-related genes also provided a molecular genetic basis for exercise-directed breeding of the Mongolian horse.
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Affiliation(s)
- Jing Pan
- Faculty of Life Sciences, Inner Mongolia Agricultural University, Hohhot, Inner Mongolia Autonomous Region, People’s Republic of China
- Department of Reproductive Medicine, Inner Mongolia Maternal and Child Health Care Hospitaly, Hohhot, Inner Mongolia Autonomous Region, People’s Republic of China
| | - Chimge Purev
- Mongolia-China Joint Laboratory of Applied Molecular Biology, “Administration of the Science Park” CSTI, Ulaanbaatar, Mongolia
| | - Hongwei Zhao
- Beijing 8omics Gene Technology Co. Ltd, Beijing, People’s Republic of China
| | - Zhipeng Zhang
- Faculty of Life Sciences, Inner Mongolia Agricultural University, Hohhot, Inner Mongolia Autonomous Region, People’s Republic of China
| | - Feng Wang
- Faculty of Life Sciences, Nankai University, Tianjin, People’s Republic of China
| | - Nashun Wendoule
- Animal Husbandry Workstation of Ewenki Autonomous County, Hulun Buir, Inner Mongolia Autonomous Region, People’s Republic of China
| | - Guichun Qi
- Bayanta Village of Animal Husbandry and Veterinary Station of Ewenki Autonomous County, Hulun Buir, Inner Mongolia Autonomous Region, People’s Republic of China
| | - Yongbin Liu
- Sheep Collaboration and Innovation Center, Inner Mongolia Universityy, Hohhot, Inner Mongolia Autonomous Region, People’s Republic of China
| | - Huanmin Zhou
- Faculty of Life Sciences, Inner Mongolia Agricultural University, Hohhot, Inner Mongolia Autonomous Region, People’s Republic of China
- Sheep Collaboration and Innovation Center, Inner Mongolia Universityy, Hohhot, Inner Mongolia Autonomous Region, People’s Republic of China
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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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Arent SM, Cintineo HP, McFadden BA, Chandler AJ, Arent MA. Nutrient Timing: A Garage Door of Opportunity? Nutrients 2020; 12:nu12071948. [PMID: 32629950 PMCID: PMC7400240 DOI: 10.3390/nu12071948] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2020] [Revised: 06/26/2020] [Accepted: 06/28/2020] [Indexed: 12/11/2022] Open
Abstract
Nutrient timing involves manipulation of nutrient consumption at specific times in and around exercise bouts in an effort to improve performance, recovery, and adaptation. Its historical perspective centered on ingestion during exercise and grew to include pre- and post-training periods. As research continued, translational focus remained primarily on the impact and outcomes related to nutrient consumption during one specific time period to the exclusion of all others. Additionally, there seemed to be increasing emphasis on outcomes related to hypertrophy and strength at the expense of other potentially more impactful performance measures. As consumption of nutrients does not occur at only one time point in the day, the effect and impact of energy and macronutrient availability becomes an important consideration in determining timing of additional nutrients in and around training and competition. This further complicates the confining of the definition of “nutrient timing” to one very specific moment in time at the exclusion of all other time points. As such, this review suggests a new perspective built on evidence of the interconnectedness of nutrient impact and provides a pragmatic approach to help frame nutrient timing more inclusively. Using this approach, it is argued that the concept of nutrient timing is constrained by reliance on interpretation of an “anabolic window” and may be better viewed as a “garage door of opportunity” to positively impact performance, recovery, and athlete availability.
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Affiliation(s)
- Shawn M. Arent
- Department of Exercise Science, University of South Carolina, Columbia, SC 29208, USA; (H.P.C.); (B.A.M.); (A.J.C.)
- Correspondence: ; Tel.: +1-803-576-8394
| | - Harry P. Cintineo
- Department of Exercise Science, University of South Carolina, Columbia, SC 29208, USA; (H.P.C.); (B.A.M.); (A.J.C.)
| | - Bridget A. McFadden
- Department of Exercise Science, University of South Carolina, Columbia, SC 29208, USA; (H.P.C.); (B.A.M.); (A.J.C.)
| | - Alexa J. Chandler
- Department of Exercise Science, University of South Carolina, Columbia, SC 29208, USA; (H.P.C.); (B.A.M.); (A.J.C.)
| | - Michelle A. Arent
- Department of Health Promotion, Education, and Behavior, University of South Carolina, Columbia, SC 29208, USA;
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Exercise Mitigates the Loss of Muscle Mass by Attenuating the Activation of Autophagy during Severe Energy Deficit. Nutrients 2019; 11:nu11112824. [PMID: 31752260 PMCID: PMC6893734 DOI: 10.3390/nu11112824] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2019] [Revised: 10/30/2019] [Accepted: 11/14/2019] [Indexed: 01/07/2023] Open
Abstract
The loss of skeletal muscle mass with energy deficit is thought to be due to protein breakdown by the autophagy-lysosome and the ubiquitin-proteasome systems. We studied the main signaling pathways through which exercise can attenuate the loss of muscle mass during severe energy deficit (5500 kcal/day). Overweight men followed four days of caloric restriction (3.2 kcal/kg body weight day) and prolonged exercise (45 min of one-arm cranking and 8 h walking/day), and three days of control diet and restricted exercise, with an intra-subject design including biopsies from muscles submitted to distinct exercise volumes. Gene expression and signaling data indicate that the main catabolic pathway activated during severe energy deficit in skeletal muscle is the autophagy-lysosome pathway, without apparent activation of the ubiquitin-proteasome pathway. Markers of autophagy induction and flux were reduced by exercise primarily in the muscle submitted to an exceptional exercise volume. Changes in signaling are associated with those in circulating cortisol, testosterone, cortisol/testosterone ratio, insulin, BCAA, and leucine. We conclude that exercise mitigates the loss of muscle mass by attenuating autophagy activation, blunting the phosphorylation of AMPK/ULK1/Beclin1, and leading to p62/SQSTM1 accumulation. This includes the possibility of inhibiting autophagy as a mechanism to counteract muscle loss in humans under severe energy deficit.
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Gieske BT, Stecker RA, Smith CR, Witherbee KE, Harty PS, Wildman R, Kerksick CM. Metabolic impact of protein feeding prior to moderate-intensity treadmill exercise in a fasted state: a pilot study. J Int Soc Sports Nutr 2018; 15:56. [PMID: 30497484 PMCID: PMC6267781 DOI: 10.1186/s12970-018-0263-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2018] [Accepted: 11/13/2018] [Indexed: 12/21/2022] Open
Abstract
Background Augmenting fat oxidation is a primary goal of fitness enthusiasts and individuals desiring to improve their body composition. Performing aerobic exercise while fasted continues to be a popular strategy to achieve this outcome, yet little research has examined how nutritional manipulations influence energy expenditure and/or fat oxidation during and after exercise. Initial research has indicated that pre-exercise protein feeding may facilitate fat oxidation while minimizing protein degradation during exercise, but more research is needed to determine if the source of protein further influences such outcomes. Methods Eleven healthy, college-aged males (23.5 ± 2.1 years, 86.0 ± 15.6 kg, 184 ± 10.3 cm, 19.7 ± 4.4%fat) completed four testing sessions in a randomized, counter-balanced, crossover fashion after observing an 8–10 h fast. During each visit, baseline substrate oxidation and resting energy expenditure (REE) were assessed via indirect calorimetry. Participants ingested isovolumetric, solutions containing 25 g of whey protein isolate (WPI), 25 g of casein protein (CAS), 25 g of maltodextrin (MAL), or non-caloric control (CON). After 30 min, participants performed 30 min of treadmill exercise at 55–60% heart rate reserve. Substrate oxidation and energy expenditure were re-assessed during exercise and 15 min after exercise. Results Delta scores comparing the change in REE were normalized to body mass and a significant group x time interaction (p = 0.002) was found. Post-hoc comparisons indicated the within-group changes in REE following consumption of WPI (3.41 ± 1.63 kcal/kg) and CAS (3.39 ± 0.82 kcal/kg) were significantly greater (p < 0.05) than following consumption of MAL (1.57 ± 0.99 kcal/kg) and tended to be greater than the non-caloric control group (2.00 ± 1.91 kcal/kg, p = 0.055 vs. WPI and p = 0.061 vs. CAS). Respiratory exchange ratio following consumption of WPI and CAS significantly decreased during the post exercise period while no change was observed for the other groups. Fat oxidation during exercise was calculated and increased in all groups throughout exercise. CAS was found to oxidize significantly more fat (p < 0.05) than WPI during minutes 10–15 (CAS: 2.28 ± 0.38 g; WPI: 1.7 ± 0.60 g) and 25–30 (CAS: 3.03 ± 0.55 g; WPI: 2.24 ± 0.50 g) of the exercise bout. Conclusions Protein consumption before fasted moderate-intensity treadmill exercise significantly increased post-exercise energy expenditure compared to maltodextrin ingestion and tended to be greater than control. Post-exercise fat oxidation was improved following protein ingestion. Throughout exercise, fasting (control) did not yield more fat oxidation versus carbohydrate or protein, while casein protein allowed for more fat oxidation than whey. These results indicate rates of energy expenditure and fat oxidation can be modulated after CAS protein consumption prior to moderate-intensity cardiovascular exercise and that fasting did not lead to more fat oxidation during or after exercise.
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Affiliation(s)
- Bradley T Gieske
- Exercise and Performance Nutrition Laboratory, School of Health Sciences, Lindenwood University, St. Charles, MO, 63301, USA
| | - Richard A Stecker
- Exercise and Performance Nutrition Laboratory, School of Health Sciences, Lindenwood University, St. Charles, MO, 63301, USA
| | - Charles R Smith
- Department of Exercise Science, Arnold School of Public Health, University of South Carolina, Columbia, USA
| | - Kyle E Witherbee
- Exercise and Performance Nutrition Laboratory, School of Health Sciences, Lindenwood University, St. Charles, MO, 63301, USA
| | - Patrick S Harty
- Exercise and Performance Nutrition Laboratory, School of Health Sciences, Lindenwood University, St. Charles, MO, 63301, USA
| | - Robert Wildman
- Department of Food and Nutrition Sciences, Texas Woman's University, Denton, TX, USA
| | - Chad M Kerksick
- Exercise and Performance Nutrition Laboratory, School of Health Sciences, Lindenwood University, St. Charles, MO, 63301, USA.
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Abstract
Muscle protein breakdown (MPB) is an important metabolic component of muscle remodeling, adaptation to training, and increasing muscle mass. Degradation of muscle proteins occurs via the integration of three main systems—autophagy and the calpain and ubiquitin-proteasome systems. These systems do not operate independently, and the regulation is complex. Complete degradation of a protein requires some combination of the systems. Determination of MPB in humans is technically challenging, leading to a relative dearth of information. Available information on the dynamic response of MPB primarily comes from stable isotopic methods with expression and activity measures providing complementary information. It seems clear that resistance exercise increases MPB, but not as much as the increase in muscle protein synthesis. Both hyperaminoacidemia and hyperinsulinemia inhibit the post-exercise response of MPB. Available data do not allow a comprehensive examination of the mechanisms behind these responses. Practical nutrition recommendations for interventions to suppress MPB following exercise are often made. However, it is likely that some degree of increased MPB following exercise is an important component for optimal remodeling. At this time, it is not possible to determine the impact of nutrition on any individual muscle protein. Thus, until we can develop and employ better methods to elucidate the role of MPB following exercise and the response to nutrition, recommendations to optimize post exercise nutrition should focus on the response of muscle protein synthesis. The aim of this review is to provide a comprehensive examination of the state of knowledge, including methodological considerations, of the response of MPB to exercise and nutrition in humans.
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Roberts MD, Haun CT, Mobley CB, Mumford PW, Romero MA, Roberson PA, Vann CG, McCarthy JJ. Physiological Differences Between Low Versus High Skeletal Muscle Hypertrophic Responders to Resistance Exercise Training: Current Perspectives and Future Research Directions. Front Physiol 2018; 9:834. [PMID: 30022953 PMCID: PMC6039846 DOI: 10.3389/fphys.2018.00834] [Citation(s) in RCA: 67] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2018] [Accepted: 06/13/2018] [Indexed: 12/22/2022] Open
Abstract
Numerous reports suggest there are low and high skeletal muscle hypertrophic responders following weeks to months of structured resistance exercise training (referred to as low and high responders herein). Specifically, divergent alterations in muscle fiber cross sectional area (fCSA), vastus lateralis thickness, and whole body lean tissue mass have been shown to occur in high versus low responders. Differential responses in ribosome biogenesis and subsequent protein synthetic rates during training seemingly explain some of this individual variation in humans, and mechanistic in vitro and rodent studies provide further evidence that ribosome biogenesis is critical for muscle hypertrophy. High responders may experience a greater increase in satellite cell proliferation during training versus low responders. This phenomenon could serve to maintain an adequate myonuclear domain size or assist in extracellular remodeling to support myofiber growth. High responders may also express a muscle microRNA profile during training that enhances insulin-like growth factor-1 (IGF-1) mRNA expression, although more studies are needed to better validate this mechanism. Higher intramuscular androgen receptor protein content has been reported in high versus low responders following training, and this mechanism may enhance the hypertrophic effects of testosterone during training. While high responders likely possess “good genetics,” such evidence has been confined to single gene candidates which typically share marginal variance with hypertrophic outcomes following training (e.g., different myostatin and IGF-1 alleles). Limited evidence also suggests pre-training muscle fiber type composition and self-reported dietary habits (e.g., calorie and protein intake) do not differ between high versus low responders. Only a handful of studies have examined muscle biomarkers that are differentially expressed between low versus high responders. Thus, other molecular and physiological variables which could potentially affect the skeletal muscle hypertrophic response to resistance exercise training are also discussed including rDNA copy number, extracellular matrix and connective tissue properties, the inflammatory response to training, and mitochondrial as well as vascular characteristics.
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Affiliation(s)
| | - Cody T Haun
- School of Kinesiology, Auburn University, Auburn, AL, United States
| | | | - Petey W Mumford
- School of Kinesiology, Auburn University, Auburn, AL, United States
| | - Matthew A Romero
- School of Kinesiology, Auburn University, Auburn, AL, United States
| | - Paul A Roberson
- School of Kinesiology, Auburn University, Auburn, AL, United States
| | | | - John J McCarthy
- Department of Physiology, University of Kentucky College of Medicine, Lexington, KY, United States
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11
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Mobley CB, Haun CT, Roberson PA, Mumford PW, Kephart WC, Romero MA, Osburn SC, Vann CG, Young KC, Beck DT, Martin JS, Lockwood CM, Roberts MD. Biomarkers associated with low, moderate, and high vastus lateralis muscle hypertrophy following 12 weeks of resistance training. PLoS One 2018; 13:e0195203. [PMID: 29621305 PMCID: PMC5886420 DOI: 10.1371/journal.pone.0195203] [Citation(s) in RCA: 63] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2017] [Accepted: 03/19/2018] [Indexed: 12/20/2022] Open
Abstract
We sought to identify biomarkers which delineated individual hypertrophic responses to resistance training. Untrained, college-aged males engaged in full-body resistance training (3 d/wk) for 12 weeks. Body composition via dual x-ray absorptiometry (DXA), vastus lateralis (VL) thickness via ultrasound, blood, VL muscle biopsies, and three-repetition maximum (3-RM) squat strength were obtained prior to (PRE) and following (POST) 12 weeks of training. K-means cluster analysis based on VL thickness changes identified LOW [n = 17; change (mean±SD) = +0.11±0.14 cm], modest (MOD; n = 29, +0.40±0.06 cm), and high (HI; n = 21, +0.69±0.14 cm) responders. Biomarkers related to histology, ribosome biogenesis, proteolysis, inflammation, and androgen signaling were analyzed between clusters. There were main effects of time (POST>PRE, p<0.05) but no cluster×time interactions for increases in DXA lean body mass, type I and II muscle fiber cross sectional area and myonuclear number, satellite cell number, and macronutrients consumed. Interestingly, PRE VL thickness was ~12% greater in LOW versus HI (p = 0.021), despite POST values being ~12% greater in HI versus LOW (p = 0.006). However there was only a weak correlation between PRE VL thickness scores and change in VL thickness (r2 = 0.114, p = 0.005). Forced post hoc analysis indicated that muscle total RNA levels (i.e., ribosome density) did not significantly increase in the LOW cluster (351±70 ng/mg to 380±62, p = 0.253), but increased in the MOD (369±115 to 429±92, p = 0.009) and HI clusters (356±77 to 470±134, p<0.001; POST HI>POST LOW, p = 0.013). Nonetheless, there was only a weak association between change in muscle total RNA and VL thickness (r2 = 0.079, p = 0.026). IL-1β mRNA levels decreased in the MOD and HI clusters following training (p<0.05), although associations between this marker and VL thickness changes were not significant (r2 = 0.0002, p = 0.919). In conclusion, individuals with lower pre-training VL thickness values and greater increases muscle total RNA levels following 12 weeks of resistance training experienced greater VL muscle growth, although these biomarkers individually explained only ~8–11% of the variance in hypertrophy.
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Affiliation(s)
| | - Cody T. Haun
- School of Kinesiology, Auburn University, Auburn, AL, United States of America
| | - Paul A. Roberson
- School of Kinesiology, Auburn University, Auburn, AL, United States of America
| | - Petey W. Mumford
- School of Kinesiology, Auburn University, Auburn, AL, United States of America
| | - Wesley C. Kephart
- School of Kinesiology, Auburn University, Auburn, AL, United States of America
| | - Matthew A. Romero
- School of Kinesiology, Auburn University, Auburn, AL, United States of America
| | - Shelby C. Osburn
- School of Kinesiology, Auburn University, Auburn, AL, United States of America
| | - Christopher G. Vann
- School of Kinesiology, Auburn University, Auburn, AL, United States of America
| | - Kaelin C. Young
- School of Kinesiology, Auburn University, Auburn, AL, United States of America
- Department of Cell Biology and Physiology, Edward Via College of Osteopathic Medicine–Auburn Campus, Auburn, AL, United States of America
| | - Darren T. Beck
- School of Kinesiology, Auburn University, Auburn, AL, United States of America
- Department of Cell Biology and Physiology, Edward Via College of Osteopathic Medicine–Auburn Campus, Auburn, AL, United States of America
| | - Jeffrey S. Martin
- School of Kinesiology, Auburn University, Auburn, AL, United States of America
- Department of Cell Biology and Physiology, Edward Via College of Osteopathic Medicine–Auburn Campus, Auburn, AL, United States of America
| | | | - Michael D. Roberts
- School of Kinesiology, Auburn University, Auburn, AL, United States of America
- Department of Cell Biology and Physiology, Edward Via College of Osteopathic Medicine–Auburn Campus, Auburn, AL, United States of America
- * E-mail:
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12
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Romero MA, Mobley CB, Mumford PW, Roberson PA, Haun CT, Kephart WC, Healy JC, Beck DT, Young KC, Martin JS, Lockwood CM, Roberts MD. Acute and chronic resistance training downregulates select LINE-1 retrotransposon activity markers in human skeletal muscle. Am J Physiol Cell Physiol 2017; 314:C379-C388. [PMID: 29351416 DOI: 10.1152/ajpcell.00192.2017] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Herein, we examined if acute or chronic resistance exercise affected markers of skeletal muscle long interspersed nuclear element-1 (LINE-1) retrotransposon activity. In study 1, 10 resistance-trained college-aged men performed three consecutive daily back squat sessions, and vastus lateralis biopsies were taken before (Pre), 2 h following session 1 (Post1), and 3 days following session 3 (Post2). In study 2, 13 untrained college-aged men performed a full-body resistance training program (3 days/wk), and vastus lateralis biopsies were taken before ( week 0) and ~72 h following training cessation ( week 12). In study 1, LINE-1 mRNA decreased 42-48% at Post1 and 2 ( P < 0.05), and reverse transcriptase (RT) activity trended downward at Post2 (-37%, P = 0.067). In study 2, LINE-1 mRNA trended downward at week 12 (-17%, P = 0.056) while LINE-1 promoter methylation increased (+142%, P = 0.041). Open reading frame (ORF)2p protein expression (-24%, P = 0.059) and RT activity (-26%, P = 0.063) also trended downward by week 12. Additionally, changes in RT activity versus satellite cell number were inversely associated ( r = -0.725, P = 0.008). Follow-up in vitro experiments demonstrated that 48-h treatments with lower doses (1 μM and 10 μM) of efavirenz and nevirapine (non-nucleoside RT inhibitors) increased myoblast proliferation ( P < 0.05). However, we observed a paradoxical decrease in myoblast proliferation with higher doses (50 μM) of efavirenz and delavirdine. This is the first report suggesting that resistance exercise downregulates markers of skeletal muscle LINE-1 activity. Given our discordant in vitro findings, future research is needed to thoroughly assess whether LINE-1-mediated RT activity enhances or blunts myoblast, or primary satellite cell, proliferative capacity.
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Affiliation(s)
| | | | | | | | - Cody T Haun
- School of Kinesiology, Auburn University , Auburn, Alabama
| | | | - James C Healy
- School of Kinesiology, Auburn University , Auburn, Alabama.,Department of Cell Biology and Physiology, Edward Via College of Osteopathic Medicine-Auburn Campus , Auburn, Alabama
| | - Darren T Beck
- School of Kinesiology, Auburn University , Auburn, Alabama.,Department of Cell Biology and Physiology, Edward Via College of Osteopathic Medicine-Auburn Campus , Auburn, Alabama
| | - Kaelin C Young
- School of Kinesiology, Auburn University , Auburn, Alabama.,Department of Cell Biology and Physiology, Edward Via College of Osteopathic Medicine-Auburn Campus , Auburn, Alabama
| | - Jeffrey S Martin
- School of Kinesiology, Auburn University , Auburn, Alabama.,Department of Cell Biology and Physiology, Edward Via College of Osteopathic Medicine-Auburn Campus , Auburn, Alabama
| | | | - Michael D Roberts
- School of Kinesiology, Auburn University , Auburn, Alabama.,Department of Cell Biology and Physiology, Edward Via College of Osteopathic Medicine-Auburn Campus , Auburn, Alabama
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13
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Effect of eccentric action velocity on expression of genes related to myostatin signaling pathway in human skeletal muscle. Biol Sport 2017; 35:111-119. [PMID: 30455539 PMCID: PMC6234307 DOI: 10.5114/biolsport.2018.71600] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2016] [Revised: 01/12/2017] [Accepted: 10/14/2017] [Indexed: 01/05/2023] Open
Abstract
The aim of this study was to investigate the effects of an acute bout of eccentric actions, performed at fast velocity (210º.s-1) and at slow velocity (20º.s-1), on the gene expression of regulatory components of the myostatin (MSTN) signalling pathway. Participants performed an acute bout of eccentric actions at either a slow or a fast velocity. Muscle biopsy samples were taken before, immediately after, and 2 h after the exercise bout. The gene expression of the components of the MSTN pathway was assessed by real-time PCR. No change was observed in MSTN, ACTRIIB, GASP-1 or FOXO-3a gene expression after either slow or fast eccentric actions (p > 0.05). However, the MSTN inhibitors follistatin (FST), FST-like-3 (FSTL3) and SMAD-7 were significantly increased 2 h after both eccentric actions (p < 0.05). No significant difference between bouts was found before, immediately after, or 2 h after the eccentric actions (slow and fast velocities, p > 0.05). The current findings indicate that a bout of eccentric actions activates the expression of MSTN inhibitors. However, no difference was observed in MSTN inhibitors’ gene expression when comparing slow and fast eccentric actions. It is possible that the greater time under tension induced by slow eccentric (SE) actions might compensate the effect of the greater velocity of fast eccentric (FE) actions. Additional studies are required to address the effect of eccentric action (EA) velocities on the pathways related to muscle hypertrophy.
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14
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Haun CT, Mumford PW, Roberson PA, Romero MA, Mobley CB, Kephart WC, Anderson RG, Colquhoun RJ, Muddle TWD, Luera MJ, Mackey CS, Pascoe DD, Young KC, Martin JS, DeFreitas JM, Jenkins NDM, Roberts MD. Molecular, neuromuscular, and recovery responses to light versus heavy resistance exercise in young men. Physiol Rep 2017; 5:5/18/e13457. [PMID: 28963127 PMCID: PMC5617935 DOI: 10.14814/phy2.13457] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2017] [Revised: 08/30/2017] [Accepted: 09/04/2017] [Indexed: 11/24/2022] Open
Abstract
Recent evidence suggests that resistance training with light or heavy loads to failure results in similar adaptations. Herein, we compared how both training modalities affect the molecular, neuromuscular, and recovery responses following exercise. Resistance‐trained males (mean ± SE: 22 ± 2 years, 84.8 ± 9.0 kg, 1.79 ± 0.06 m; n = 15) performed a crossover design of four sets of leg extensor exercise at 30% (light RE) or 80% (heavy RE) one repetition maximum (1RM) to repetition failure, and heavy RE or light RE 1 week later. Surface electromyography (EMG) was monitored during exercise, and vastus lateralis muscle biopsies were collected at baseline (PRE), 15 min (15mPOST), and 90 min following RE (90mPOST) for examination of molecular targets and fiber typing. Isokinetic dynamometry was also performed before (PRE), immediately after (POST), and 48 h after (48hPOST) exercise. Dependent variables were analyzed using repeated measures ANOVAs and significance was set at P ≤ 0.05. Repetitions completed were greater during light RE (P < 0.01), while EMG amplitude was greater during heavy RE (P ≤ 0.01). POST isokinetic torque was reduced following light versus heavy RE (P < 0.05). Postexercise expression of mRNAs and phosphoproteins associated with muscle hypertrophy were similar between load conditions. Additionally, p70s6k (Thr389) phosphorylation and fast‐twitch fiber proportion exhibited a strong relationship after both light and heavy RE (r > 0.5). While similar mRNA and phosphoprotein responses to both modalities occurred, we posit that heavy RE is a more time‐efficient training method given the differences in total repetitions completed, lower EMG amplitude during light RE, and impaired recovery response after light RE.
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Affiliation(s)
- Cody T Haun
- School of Kinesiology, Auburn University, Auburn, Alabama
| | | | | | | | | | | | | | - Ryan J Colquhoun
- Applied Neuromuscular Physiology Laboratory, Oklahoma State University, Stillwater
| | - Tyler W D Muddle
- Applied Neuromuscular Physiology Laboratory, Oklahoma State University, Stillwater
| | - Michael J Luera
- Applied Neuromuscular Physiology Laboratory, Oklahoma State University, Stillwater
| | - Cameron S Mackey
- Applied Neuromuscular Physiology Laboratory, Oklahoma State University, Stillwater
| | - David D Pascoe
- School of Kinesiology, Auburn University, Auburn, Alabama
| | - Kaelin C Young
- School of Kinesiology, Auburn University, Auburn, Alabama.,Department of Cell Biology and Physiology, Edward Via College of Osteopathic Medicine - Auburn Campus, Auburn, Alabama
| | - Jeffrey S Martin
- School of Kinesiology, Auburn University, Auburn, Alabama.,Department of Cell Biology and Physiology, Edward Via College of Osteopathic Medicine - Auburn Campus, Auburn, Alabama
| | - Jason M DeFreitas
- Applied Neuromuscular Physiology Laboratory, Oklahoma State University, Stillwater
| | | | - Michael D Roberts
- School of Kinesiology, Auburn University, Auburn, Alabama .,Department of Cell Biology and Physiology, Edward Via College of Osteopathic Medicine - Auburn Campus, Auburn, Alabama
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15
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Jäger R, Kerksick CM, Campbell BI, Cribb PJ, Wells SD, Skwiat TM, Purpura M, Ziegenfuss TN, Ferrando AA, Arent SM, Smith-Ryan AE, Stout JR, Arciero PJ, Ormsbee MJ, Taylor LW, Wilborn CD, Kalman DS, Kreider RB, Willoughby DS, Hoffman JR, Krzykowski JL, Antonio J. International Society of Sports Nutrition Position Stand: protein and exercise. J Int Soc Sports Nutr 2017; 14:20. [PMID: 28642676 PMCID: PMC5477153 DOI: 10.1186/s12970-017-0177-8] [Citation(s) in RCA: 337] [Impact Index Per Article: 48.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2017] [Accepted: 06/05/2017] [Indexed: 01/03/2023] Open
Abstract
The International Society of Sports Nutrition (ISSN) provides an objective and critical review related to the intake of protein for healthy, exercising individuals. Based on the current available literature, the position of the Society is as follows:An acute exercise stimulus, particularly resistance exercise, and protein ingestion both stimulate muscle protein synthesis (MPS) and are synergistic when protein consumption occurs before or after resistance exercise.For building muscle mass and for maintaining muscle mass through a positive muscle protein balance, an overall daily protein intake in the range of 1.4-2.0 g protein/kg body weight/day (g/kg/d) is sufficient for most exercising individuals, a value that falls in line within the Acceptable Macronutrient Distribution Range published by the Institute of Medicine for protein.Higher protein intakes (2.3-3.1 g/kg/d) may be needed to maximize the retention of lean body mass in resistance-trained subjects during hypocaloric periods.There is novel evidence that suggests higher protein intakes (>3.0 g/kg/d) may have positive effects on body composition in resistance-trained individuals (i.e., promote loss of fat mass).Recommendations regarding the optimal protein intake per serving for athletes to maximize MPS are mixed and are dependent upon age and recent resistance exercise stimuli. General recommendations are 0.25 g of a high-quality protein per kg of body weight, or an absolute dose of 20-40 g.Acute protein doses should strive to contain 700-3000 mg of leucine and/or a higher relative leucine content, in addition to a balanced array of the essential amino acids (EAAs).These protein doses should ideally be evenly distributed, every 3-4 h, across the day.The optimal time period during which to ingest protein is likely a matter of individual tolerance, since benefits are derived from pre- or post-workout ingestion; however, the anabolic effect of exercise is long-lasting (at least 24 h), but likely diminishes with increasing time post-exercise.While it is possible for physically active individuals to obtain their daily protein requirements through the consumption of whole foods, supplementation is a practical way of ensuring intake of adequate protein quality and quantity, while minimizing caloric intake, particularly for athletes who typically complete high volumes of training. Rapidly digested proteins that contain high proportions of essential amino acids (EAAs) and adequate leucine, are most effective in stimulating MPS. Different types and quality of protein can affect amino acid bioavailability following protein supplementation. Athletes should consider focusing on whole food sources of protein that contain all of the EAAs (i.e., it is the EAAs that are required to stimulate MPS). Endurance athletes should focus on achieving adequate carbohydrate intake to promote optimal performance; the addition of protein may help to offset muscle damage and promote recovery. Pre-sleep casein protein intake (30-40 g) provides increases in overnight MPS and metabolic rate without influencing lipolysis.
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Affiliation(s)
| | - Chad M. Kerksick
- Exercise and Performance Nutrition Laboratory, School of Health Sciences, Lindenwood University, St. Charles, MO USA
| | - Bill I. Campbell
- Performance & Physique Enhancement Laboratory, University of South Florida, Tampa, FL USA
| | - Paul J. Cribb
- Metabolic Precision Certifications, Queensland, Australia
| | | | | | | | | | - Arny A. Ferrando
- Department of Geriatrics, University of Arkansas for Medical Sciences, Little Rock, AR USA
| | - Shawn M. Arent
- IFNH Center for Health & Human Performance, Department of Kinesiology & Health, Rutgers, the State University of New Jersey, New Brunswick, New Jersey USA
| | - Abbie E. Smith-Ryan
- Applied Physiology Laboratory, Department of Exercise and Sport Science, University of North Carolina, Chapel Hill, NC USA
| | - Jeffrey R. Stout
- Institute of Exercise Physiology and Wellness, University of Central Florida, Orlando, FL USA
| | - Paul J. Arciero
- Human Nutrition and Metabolism Laboratory, Health and Exercise Sciences Department, Skidmore College, Saratoga Springs, NY 12866 USA
| | - Michael J. Ormsbee
- Department of Nutrition, Food and Exercise Sciences, Institute of Sport Sciences and Medicine, Florida State University, Tallahassee, USA
- Biokinetics, Exercise and Leisure Studies, University of KwaZulu-Natal, Durban, 4000 South Africa
| | - Lem W. Taylor
- Human Performance Laboratory, University of Mary Hardin-Baylor UMHB, Belton, TX 76513 USA
| | - Colin D. Wilborn
- Human Performance Laboratory, University of Mary Hardin-Baylor UMHB, Belton, TX 76513 USA
| | - Doug S. Kalman
- Department of Nutrition & Endocrinology, QPS, Miami, FL USA
| | - Richard B. Kreider
- Exercise & Sport Nutrition Lab, Human Clinical Research Facility, Department of Health & Kinesiology, Texas A&M University, College Station, TX USA
| | - Darryn S. Willoughby
- Exercise and Biochemical Nutrition Laboratory, Department of Health, Human Performance, and Recreation, Baylor University, Waco, TX USA
| | - Jay R. Hoffman
- Institute of Exercise Physiology and Wellness, University of Central Florida, Orlando, FL USA
| | | | - Jose Antonio
- Department of Health and Human Performance, Nova Southeastern University, Davie, FL USA
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16
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Mobley CB, Holland AM, Kephart WC, Mumford PW, Lowery RP, Kavazis AN, Wilson JM, Roberts MD. Progressive resistance-loaded voluntary wheel running increases hypertrophy and differentially affects muscle protein synthesis, ribosome biogenesis, and proteolytic markers in rat muscle. J Anim Physiol Anim Nutr (Berl) 2017; 102:317-329. [DOI: 10.1111/jpn.12691] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2016] [Accepted: 01/12/2017] [Indexed: 01/04/2023]
Affiliation(s)
| | | | | | | | - R. P. Lowery
- Applied Science and Performance Institute; Tampa FL USA
| | - A. N. Kavazis
- Auburn University; Auburn AL USA
- Edward Via College of Osteopathic Medicine - Auburn Campus; Auburn AL USA
| | - J. M. Wilson
- Applied Science and Performance Institute; Tampa FL USA
| | - M. D. Roberts
- Auburn University; Auburn AL USA
- Edward Via College of Osteopathic Medicine - Auburn Campus; Auburn AL USA
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17
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Smiles WJ, Hawley JA, Camera DM. Effects of skeletal muscle energy availability on protein turnover responses to exercise. ACTA ACUST UNITED AC 2016; 219:214-25. [PMID: 26792333 DOI: 10.1242/jeb.125104] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Skeletal muscle adaptation to exercise training is a consequence of repeated contraction-induced increases in gene expression that lead to the accumulation of functional proteins whose role is to blunt the homeostatic perturbations generated by escalations in energetic demand and substrate turnover. The development of a specific 'exercise phenotype' is the result of new, augmented steady-state mRNA and protein levels that stem from the training stimulus (i.e. endurance or resistance based). Maintaining appropriate skeletal muscle integrity to meet the demands of training (i.e. increases in myofibrillar and/or mitochondrial protein) is regulated by cyclic phases of synthesis and breakdown, the rate and turnover largely determined by the protein's half-life. Cross-talk among several intracellular systems regulating protein synthesis, breakdown and folding is required to ensure protein equilibrium is maintained. These pathways include both proteasomal and lysosomal degradation systems (ubiquitin-mediated and autophagy, respectively) and the protein translational and folding machinery. The activities of these cellular pathways are bioenergetically expensive and are modified by intracellular energy availability (i.e. macronutrient intake) and the 'training impulse' (i.e. summation of the volume, intensity and frequency). As such, exercise-nutrient interactions can modulate signal transduction cascades that converge on these protein regulatory systems, especially in the early post-exercise recovery period. This review focuses on the regulation of muscle protein synthetic response-adaptation processes to divergent exercise stimuli and how intracellular energy availability interacts with contractile activity to impact on muscle remodelling.
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Affiliation(s)
- William J Smiles
- Centre for Exercise and Nutrition, Mary MacKillop Institute for Health Research, Australian Catholic University, Melbourne, VIC 3065, Australia
| | - John A Hawley
- Centre for Exercise and Nutrition, Mary MacKillop Institute for Health Research, Australian Catholic University, Melbourne, VIC 3065, Australia Research Institute for Sport and Exercise Sciences, Liverpool John Moores University, Liverpool L3 3AF, UK
| | - Donny M Camera
- Centre for Exercise and Nutrition, Mary MacKillop Institute for Health Research, Australian Catholic University, Melbourne, VIC 3065, Australia
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18
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Dalbo VJ, Roberts MD, Mobley CB, Ballmann C, Kephart WC, Fox CD, Santucci VA, Conover CF, Beggs LA, Balaez A, Hoerr FJ, Yarrow JF, Borst SE, Beck DT. Testosterone and trenbolone enanthate increase mature myostatin protein expression despite increasing skeletal muscle hypertrophy and satellite cell number in rodent muscle. Andrologia 2016; 49. [PMID: 27246614 DOI: 10.1111/and.12622] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/29/2016] [Indexed: 01/03/2023] Open
Abstract
The androgen-induced alterations in adult rodent skeletal muscle fibre cross-sectional area (fCSA), satellite cell content and myostatin (Mstn) were examined in 10-month-old Fisher 344 rats (n = 41) assigned to Sham surgery, orchiectomy (ORX), ORX + testosterone (TEST; 7.0 mg week-1 ) or ORX + trenbolone (TREN; 1.0 mg week-1 ). After 29 days, animals were euthanised and the levator ani/bulbocavernosus (LABC) muscle complex was harvested for analyses. LABC muscle fCSA was 102% and 94% higher in ORX + TEST and ORX + TREN compared to ORX (p < .001). ORX + TEST and ORX + TREN increased satellite cell numbers by 181% and 178% compared to ORX, respectively (p < .01), with no differences between conditions for myonuclear number per muscle fibre (p = .948). Mstn protein was increased 159% and 169% in the ORX + TEST and ORX + TREN compared to ORX (p < .01). pan-SMAD2/3 protein was ~30-50% greater in ORX compared to SHAM (p = .006), ORX + TEST (p = .037) and ORX + TREN (p = .043), although there were no between-treatment effects regarding phosphorylated SMAD2/3. Mstn, ActrIIb and Mighty mRNAs were lower in ORX, ORX + TEST and ORX + TREN compared to SHAM (p < .05). Testosterone and trenbolone administration increased muscle fCSA and satellite cell number without increasing myonuclei number, and increased Mstn protein levels. Several genes and signalling proteins related to myostatin signalling were differentially regulated by ORX or androgen therapy.
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Affiliation(s)
- V J Dalbo
- Medical and Applied Sciences, Central Queensland University, Rockhampton, Qld, Australia
| | - M D Roberts
- School of Kinesiology, Auburn University, Auburn, AL, USA
| | - C B Mobley
- School of Kinesiology, Auburn University, Auburn, AL, USA
| | - C Ballmann
- School of Kinesiology, Auburn University, Auburn, AL, USA
| | - W C Kephart
- School of Kinesiology, Auburn University, Auburn, AL, USA
| | - C D Fox
- School of Kinesiology, Auburn University, Auburn, AL, USA
| | - V A Santucci
- School of Kinesiology, Auburn University, Auburn, AL, USA
| | - C F Conover
- Malcom Randall Veterans Affairs Medical Center, Geriatric Research Education and Clinical Center, Gainesville, FL, USA
| | - L A Beggs
- Malcom Randall Veterans Affairs Medical Center, Geriatric Research Education and Clinical Center, Gainesville, FL, USA.,Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, FL, USA
| | - A Balaez
- Malcom Randall Veterans Affairs Medical Center, Geriatric Research Education and Clinical Center, Gainesville, FL, USA.,Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, FL, USA
| | - F J Hoerr
- Veterinary Diagnostic Pathology LLC, Auburn, AL, USA
| | - J F Yarrow
- Malcom Randall Veterans Affairs Medical Center, Geriatric Research Education and Clinical Center, Gainesville, FL, USA.,Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, FL, USA
| | - S E Borst
- Malcom Randall Veterans Affairs Medical Center, Geriatric Research Education and Clinical Center, Gainesville, FL, USA.,Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, FL, USA
| | - D T Beck
- Department of Cell Biology and Physiology, Edward Via College of Osteopathic Medicine-Auburn Campus, Auburn, AL, USA
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19
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Wadley AJ, Turner JE, Aldred S. Factors influencing post-exercise plasma protein carbonyl concentration. Free Radic Res 2016; 50:375-84. [PMID: 26873473 DOI: 10.3109/10715762.2015.1131824] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Exercise of sufficient intensity and duration can cause acute oxidative stress. Plasma protein carbonyl (PC) moieties are abundant, chemically stable, and easily detectable markers of oxidative stress that are widely used for the interpretation of exercise-induced changes in redox balance. Despite many studies reporting acute increases in plasma PC concentration in response to exercise, some studies, including those from our own laboratory have shown decreases. This review will discuss the differences between studies reporting increases, decreases, and no change in plasma PC concentration following exercise in humans; highlighting participant physiology (i.e. training status) and study design (i.e. intensity, duration, and novelty of the exercise bout) as the main factors driving the direction of the PC response to exercise. The role of the 20S proteasome system is proposed as a possible mechanism mediating the clearance of plasma PC following exercise. Resting and exercise-induced differences in plasma protein composition and balance between tissues are also discussed. We suggest that exercise may stimulate the clearance of plasma PC present at baseline, whereas simultaneously increasing reactive oxygen species production that facilitates the formation of new PC groups. The balance between these two processes likely explains why some studies have reported no change or even decreases in plasma PC level post-exercise when other biomarkers of oxidative stress (e.g. markers of lipid peroxidation) were elevated. Future studies should determine factors that influence the balance between PC clearance and formation following acute exercise.
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Affiliation(s)
- Alex J Wadley
- a Institute of Science and the Environment , University of Worcester , Worcester , UK
| | - James E Turner
- b School of Sport, Exercise & Rehabilitation Sciences , University of Birmingham , Edgbaston , Birmingham , UK
| | - Sarah Aldred
- c Department for Health , University of Bath , Bath , UK
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20
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Martin JS, Kephart WC, Mobley CB, Wilson TJ, Goodlett MD, Roberts MD. A single 60-min bout of peristaltic pulse external pneumatic compression transiently upregulates phosphorylated ribosomal protein s6. Clin Physiol Funct Imaging 2016; 37:602-609. [PMID: 26769680 DOI: 10.1111/cpf.12343] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2015] [Accepted: 12/09/2015] [Indexed: 11/28/2022]
Abstract
We investigated whether a single 60-min bout of whole leg, peristaltic pulse external pneumatic compression (EPC) altered select growth factor-related mRNAs and/or various phospho(p)-proteins related to cell growth, proliferation, inflammation and apoptosis signalling (e.g. Akt-mTOR, Jak-Stat). Ten participants (8 males, 2 females; aged 22·2 ± 0·4 years) reported to the laboratory 4 h post-prandial, and vastus lateralis muscle biopsies were obtained prior to (PRE), 1 h and 4 h post-EPC treatment. mRNA expression was analysed using real-time RT-PCR and phosphophorylated and cleaved proteins were analysed using an antibody array. No changes in selected growth factor-related mRNAs were observed following EPC. All p-proteins significantly altered by EPC decreased, except for p-rps6 (Ser235/236) which increased 31% 1 h post-EPC compared to PRE levels (P = 0·016). Notable decreases also included p-BAD (Ser112; -28%, P = 0·004) at 4 h post-EPC compared to PRE levels. In summary, an acute bout of EPC transiently upregulates p-rps6 as well as affecting other markers in the Akt-mTOR signalling cascade. Future research should characterize whether chronic EPC application promotes alterations in lower-limb musculature and/or enhances exercise-induced training adaptations.
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Affiliation(s)
- J S Martin
- Department of Cell Biology and Physiology, Edward Via College of Osteopathic Medicine - Auburn Campus, Auburn, AL, USA.,School of Kinesiology, Auburn University, Auburn, AL, USA
| | - W C Kephart
- School of Kinesiology, Auburn University, Auburn, AL, USA
| | - C B Mobley
- School of Kinesiology, Auburn University, Auburn, AL, USA
| | | | - M D Goodlett
- Department of Cell Biology and Physiology, Edward Via College of Osteopathic Medicine - Auburn Campus, Auburn, AL, USA.,Athletics Department, Auburn University, Auburn, AL, USA
| | - M D Roberts
- Department of Cell Biology and Physiology, Edward Via College of Osteopathic Medicine - Auburn Campus, Auburn, AL, USA.,School of Kinesiology, Auburn University, Auburn, AL, USA
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21
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Nam J, Perera P, Gordon R, Jeong YH, Blazek AD, Kim DG, Tee BC, Sun Z, Eubank TD, Zhao Y, Lablebecioglu B, Liu S, Litsky A, Weisleder NL, Lee BS, Butterfield T, Schneyer AL, Agarwal S. Follistatin-like 3 is a mediator of exercise-driven bone formation and strengthening. Bone 2015; 78:62-70. [PMID: 25937185 PMCID: PMC4466155 DOI: 10.1016/j.bone.2015.04.038] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/23/2015] [Revised: 04/15/2015] [Accepted: 04/24/2015] [Indexed: 11/17/2022]
Abstract
Exercise is vital for maintaining bone strength and architecture. Follistatin-like 3 (FSTL3), a member of follistatin family, is a mechanosensitive protein upregulated in response to exercise and is involved in regulating musculoskeletal health. Here, we investigated the potential role of FSTL3 in exercise-driven bone remodeling. Exercise-dependent regulation of bone structure and functions was compared in mice with global Fstl3 gene deletion (Fstl3-/-) and their age-matched Fstl3+/+ littermates. Mice were exercised by low-intensity treadmill walking. The mechanical properties and mineralization were determined by μCT, three-point bending test and sequential incorporation of calcein and alizarin complexone. ELISA, Western-blot analysis and qRT-PCR were used to analyze the regulation of FSTL3 and associated molecules in the serum specimens and tissues. Daily exercise significantly increased circulating FSTL3 levels in mice, rats and humans. Compared to age-matched littermates, Fstl3-/- mice exhibited significantly lower fracture tolerance, having greater stiffness, but lower strain at fracture and yield energy. Furthermore, increased levels of circulating FSTL3 in young mice paralleled greater strain at fracture compared to the lower levels of FSTL3 in older mice. More significantly, Fstl3-/- mice exhibited loss of mechanosensitivity and irresponsiveness to exercise-dependent bone formation as compared to their Fstl3+/+ littermates. In addition, FSTL3 gene deletion resulted in loss of exercise-dependent sclerostin regulation in osteocytes and osteoblasts, as compared to Fstl3+/+ osteocytes and osteoblasts, in vivo and in vitro. The data identify FSTL3 as a critical mediator of exercise-dependent bone formation and strengthening and point to its potential role in bone health and in musculoskeletal diseases.
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Affiliation(s)
- J Nam
- Department of Bioengineering, University of California, Riverside, CA 92507, USA.
| | - P Perera
- Division of Biosciences, The Ohio State University College of Dentistry, Columbus, OH 43210, USA
| | - R Gordon
- Division of Biosciences, The Ohio State University College of Dentistry, Columbus, OH 43210, USA
| | - Y H Jeong
- Division of Orthodontics, The Ohio State University College of Dentistry, Columbus, OH 43210, USA
| | - A D Blazek
- Department of Physiology and Cell Biology, The Ohio State University, Columbus, OH 43210, USA
| | - D G Kim
- Division of Orthodontics, The Ohio State University College of Dentistry, Columbus, OH 43210, USA
| | - B C Tee
- Division of Orthodontics, The Ohio State University College of Dentistry, Columbus, OH 43210, USA
| | - Z Sun
- Division of Orthodontics, The Ohio State University College of Dentistry, Columbus, OH 43210, USA
| | - T D Eubank
- Department of Internal Medicine, The Ohio State University College of Medicine, Columbus, OH 43210, USA
| | - Y Zhao
- Department of Biomedical Engineering, The Ohio State University, Columbus, OH 43210, USA
| | - B Lablebecioglu
- Division of Periodontics, The Ohio State University College of Dentistry, Columbus, OH 43210, USA
| | - S Liu
- Hormel Institute, University of Minnesota, MN 55901, USA
| | - A Litsky
- Department of Biomedical Engineering, The Ohio State University, Columbus, OH 43210, USA; Department of Orthopedics, The Ohio State University College of Medicine, Columbus, OH 43210, USA
| | - N L Weisleder
- Department of Physiology and Cell Biology, The Ohio State University, Columbus, OH 43210, USA
| | - B S Lee
- Department of Physiology and Cell Biology, The Ohio State University, Columbus, OH 43210, USA
| | - T Butterfield
- Department of Physiology, University of Kentucky, Lexington, KY 40536, USA
| | - A L Schneyer
- Department of Veterinary and Animal Science, University of Massachusetts-Amherst, MA 01003, USA
| | - S Agarwal
- Division of Biosciences, The Ohio State University College of Dentistry, Columbus, OH 43210, USA; Department of Orthopedics, The Ohio State University College of Medicine, Columbus, OH 43210, USA
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22
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Mobley CB, Hornberger TA, Fox CD, Healy JC, Ferguson BS, Lowery RP, McNally RM, Lockwood CM, Stout JR, Kavazis AN, Wilson JM, Roberts MD. Effects of oral phosphatidic acid feeding with or without whey protein on muscle protein synthesis and anabolic signaling in rodent skeletal muscle. J Int Soc Sports Nutr 2015; 12:32. [PMID: 26279644 PMCID: PMC4537536 DOI: 10.1186/s12970-015-0094-7] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2015] [Accepted: 08/09/2015] [Indexed: 11/10/2022] Open
Abstract
Background Phosphatidic acid (PA) is a diacyl-glycerophospholipid that acts as a signaling molecule in numerous cellular processes. Recently, PA has been proposed to stimulate skeletal muscle protein accretion, but mechanistic studies are lacking. Furthermore, it is unknown whether co-ingesting PA with other leucine-containing ingredients can enhance intramuscular anabolic signaling mechanisms. Thus, the purpose of this study was to examine if oral PA feeding acutely increases anabolic signaling markers and muscle protein synthesis (MPS) in gastrocnemius with and without whey protein concentrate (WPC). Methods Overnight fasted male Wistar rats (~250 g) were randomly assigned to four groups: control (CON, n = 6-13), PA (29 mg; n = 8), WPC (197 mg; n = 8), or PA + WPC (n = 8). Three hours post-feeding, gastrocnemius muscle was removed for markers of Akt-mTOR signaling, gene expression patterns related to skeletal muscle mass regulation and metabolism, and MPS analysis via the SUnSET method. Results Compared to CON rats, PA, WPC and PA + WPC resulted in a significant elevation in the phosphorylation of mTOR (Ser2481) and rps6 (Ser235/236) (p < 0.05) in the gastrocnemius though there were no differences between the supplemented groups. MPS levels in the gastrocnemius were significantly (p < 0.05) elevated in WPC versus CON rats, and tended to be elevated in PA versus CON rats (p = 0.08), though MPS was less in PA + WPC versus WPC rats (p < 0.05) in spite of robust increases in mTOR pathway activity markers in the former group. C2C12 myoblast data agreed with the in vivo data herein showing that PA increased MPS levels 51 % (p < 0.001) phosphorylated p70s6k (Thr389) levels 67 % (p < 0.001). Conclusions Our results are the first in vivo evidence to demonstrate that PA tends to increases MPS 3 h post-feeding, though PA may delay WPC-mediated MPS kinetics within a 3 h post-feeding window.
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Affiliation(s)
| | - Troy A Hornberger
- Department of Comparative Biosciences, University of Wisconsin-Madison, Madison, WI USA
| | - Carlton D Fox
- School of Kinesiology, Auburn University, Auburn, AL USA
| | - James C Healy
- School of Kinesiology, Auburn University, Auburn, AL USA
| | | | - Ryan P Lowery
- Department of Health Sciences and Human Performance, University of Tampa, Tampa, FL USA
| | - Rachel M McNally
- Department of Comparative Biosciences, University of Wisconsin-Madison, Madison, WI USA
| | | | - Jeffrey R Stout
- Human Performance Laboratory, University of Central Florida, Orlando, FL USA
| | | | - Jacob M Wilson
- Department of Health Sciences and Human Performance, University of Tampa, Tampa, FL USA
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23
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Kerschan-Schindl K, Thalmann MM, Weiss E, Tsironi M, Föger-Samwald U, Meinhart J, Skenderi K, Pietschmann P. Changes in Serum Levels of Myokines and Wnt-Antagonists after an Ultramarathon Race. PLoS One 2015; 10:e0132478. [PMID: 26147574 PMCID: PMC4493015 DOI: 10.1371/journal.pone.0132478] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2015] [Accepted: 06/15/2015] [Indexed: 01/12/2023] Open
Abstract
BACKGROUND Regular physical activities have a positive effect on the muscular skeletal system but overstrenuous exercise may be different. Transiently suppressed bone formation and increased bone resorption after participation in a 246-km ultradistance race has been demonstrated. PURPOSE The aim of this study was to analyze effects of the Spartathlon race on novel musculoskeletal markers. METHODS Venous blood samples were obtained before and immediately after the race from 19 participants of the Spartathlon. From 9 runners who were available 3 days after the start blood was drawn for a third time. Serum levels of myostatin, an inhibitor of myogenic differentiation, and its opponent follistatin as well as sclerostin and dickkopf-1, both of them inhibitors of the wnt signaling pathway, and markers of bone turnover were determined. RESULTS Serum levels of myostatin were significantly higher after the race. Serum follistatin only showed a transient increase. Sclerostin levels did not significantly differ before and after the race, whereas dickkopf-1 levels were significantly decreased. At follow-up a decrement of sclerostin and dickkopf-1 levels was seen. Serum cathepsin K levels did not change. CONCLUSION The increase of serum levels of myostatin appears to reflect muscle catabolic processes induced by overstrenuous exercise. After the short-term uncoupling of bone turnover participation in an ultradistance race seems to initiate a long-term positive effect on bone indicated by the low-level inhibition of the Wnt/β-catenin signaling pathway.
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Affiliation(s)
- Katharina Kerschan-Schindl
- Department of Physical Medicine and Rehabilitation, Medical University of Vienna, Vienna, Austria
- * E-mail:
| | - Markus M. Thalmann
- Department of Cardiovascular Surgery, Hospital Hietzing, Vienna, Austria
| | - Elisabeth Weiss
- Department of Pathophysiology and Allergy Research, Center for Pathophysiology, Infectiology and Immunology, Medical University of Vienna, Vienna, Austria
| | - Maria Tsironi
- School of Nursing, University of Peloponnese, Sparta, Greece
| | - Ursula Föger-Samwald
- Department of Pathophysiology and Allergy Research, Center for Pathophysiology, Infectiology and Immunology, Medical University of Vienna, Vienna, Austria
| | - Johann Meinhart
- Karl Landsteiner Institute for Cardiovascular Surgical Research, Vienna, Austria
| | - Katerina Skenderi
- Department of Nutrition and Dietetics, Harokopio University, Athens, Greece
| | - Peter Pietschmann
- Department of Pathophysiology and Allergy Research, Center for Pathophysiology, Infectiology and Immunology, Medical University of Vienna, Vienna, Austria
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24
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Kephart WC, Mobley CB, Fox CD, Pascoe DD, Sefton JM, Wilson TJ, Goodlett MD, Kavazis AN, Roberts MD, Martin JS. A single bout of whole-leg, peristaltic pulse external pneumatic compression upregulates PGC-1α mRNA and endothelial nitric oxide sythase protein in human skeletal muscle tissue. Exp Physiol 2015; 100:852-64. [PMID: 25982469 DOI: 10.1113/ep085160] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2015] [Accepted: 05/13/2015] [Indexed: 12/22/2022]
Abstract
NEW FINDINGS What is the central question of this study? Does 60 min of peristaltic pulse external pneumatic compression (EPC) alter gene and protein expression patterns related to metabolism, vascular biology, redox balance and inflammation in vastus lateralis biopsy samples? What is the main finding and its importance? A single bout of EPC transiently upregulates PGC-1α mRNA, while also upregulating endothelial nitric oxide synthase protein and nitric oxide metabolite concentrations in vastus lateralis biopsy samples. We investigated whether a single 60 min bout of whole-leg, lower pressure external pneumatic compression (EPC) altered select vascular, metabolic, antioxidant and inflammation-related mRNAs. Ten participants (eight male, two female; aged 22.0 ± 0.4 years) reported to the laboratory 4 h postprandial, and vastus lateralis muscle biopsies were obtained before (PRE) and 1 and 4 h after EPC treatment. Messenger RNA expression was analysed using real-time RT-PCR, and significant mRNA findings were investigated further by Western blot analysis of respective protein concentrations. Peroxisome proliferator-activated receptor γ coactivator-1α (PGC-1α) mRNA increased by 77% 1 h following EPC compared with PRE levels (P = 0.005), but no change in protein concentration 1 or 4 h post-EPC was observed. Increases in endothelial nitric oxide sythase (eNOS) mRNA (+44%) and superoxide dismutase 2 (SOD2) mRNA (+57%) 1 h post-EPC as well as an increase in interleukin-10 mRNA (+132%) 4 h post-EPC compared with PRE levels were observed, but only approached significance (P = 0.076, 0.077 and 0.074, respectively). Interestingly, eNOS protein (+40%, P = 0.025) and nitrate and nitrite (NOx) concentrations (+69%, P = 0.025) increased 1-4 h post-EPC. Moreover, SOD2 protein tended to increase from PRE to 4 h post-EPC (+43%, P = 0.074), although no changes in tissue 4-hydroxnonenal levels was observed. An acute bout of EPC transiently upregulates PGC-1α mRNA, while also upregulating eNOS protein and NOx concentrations in vastus lateralis biopsy samples. Future research should characterize the origin of these responses (e.g. vascular or muscle fibre cells) and how the acute effects of EPC application on gene and protein expression observed herein are associated with functional improvements (e.g. metabolism, vascular function) in acute and chronic models.
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Affiliation(s)
| | | | - Carlton D Fox
- School of Kinesiology, Auburn University, Auburn, AL, USA
| | - David D Pascoe
- School of Kinesiology, Auburn University, Auburn, AL, USA.,Department of Cell Biology and Physiology, Edward Via College of Osteopathic Medicine - Auburn Campus, Auburn, AL, USA
| | | | | | - Michael D Goodlett
- Department of Cell Biology and Physiology, Edward Via College of Osteopathic Medicine - Auburn Campus, Auburn, AL, USA.,Athletic Department, Auburn University, Auburn, AL, USA
| | | | - Michael D Roberts
- School of Kinesiology, Auburn University, Auburn, AL, USA.,Department of Cell Biology and Physiology, Edward Via College of Osteopathic Medicine - Auburn Campus, Auburn, AL, USA
| | - Jeffrey S Martin
- School of Kinesiology, Auburn University, Auburn, AL, USA.,Department of Cell Biology and Physiology, Edward Via College of Osteopathic Medicine - Auburn Campus, Auburn, AL, USA
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25
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Affiliation(s)
- Milène Catoire
- Nutrition, Metabolism and Genomics Group, Division of Human NutritionWageningen UniversityWageningenThe Netherlands
| | - Sander Kersten
- Nutrition, Metabolism and Genomics Group, Division of Human NutritionWageningen UniversityWageningenThe Netherlands
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26
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Mobley CB, Fox CD, Ferguson BS, Amin RH, Dalbo VJ, Baier S, Rathmacher JA, Wilson JM, Roberts MD. L-leucine, beta-hydroxy-beta-methylbutyric acid (HMB) and creatine monohydrate prevent myostatin-induced Akirin-1/Mighty mRNA down-regulation and myotube atrophy. J Int Soc Sports Nutr 2014; 11:38. [PMID: 25132809 PMCID: PMC4134516 DOI: 10.1186/1550-2783-11-38] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2014] [Accepted: 06/30/2014] [Indexed: 12/03/2022] Open
Abstract
Background The purpose of this study was to examine if L-leucine (Leu), β-hydroxy-β-methylbutyrate (HMB), or creatine monohydrate (Crea) prevented potential atrophic effects of myostatin (MSTN) on differentiated C2C12 myotubes. Methods After four days of differentiation, myotubes were treated with MSTN (10 ng/ml) for two additional days and four treatment groups were studied: 1) 3x per day 10 mM Leu, 2) 3x per day 10 mM HMB, 3) 3x per day 10 mM Crea, 4) DM only. Myotubes treated with DM without MSTN were analyzed as the control condition (DM/CTL). Following treatment, cells were analyzed for total protein, DNA content, RNA content, muscle protein synthesis (MPS, SUnSET method), and fiber diameter. Separate batch treatments were analyzed for mRNA expression patterns of myostatin-related genes (Akirin-1/Mighty, Notch-1, Ski, MyoD) as well as atrogenes (MuRF-1, and MAFbx/Atrogin-1). Results MSTN decreased fiber diameter approximately 30% compared to DM/CTL myotubes (p < 0.001). Leu, HMB and Crea prevented MSTN-induced atrophy. MSTN did not decrease MPS levels compared to DM/CTL myotubes, but MSTN treatment decreased the mRNA expression of Akirin-1/Mighty by 27% (p < 0.001) and MyoD by 26% (p < 0.01) compared to DM/CTL myotubes. shRNA experiments confirmed that Mighty mRNA knockdown reduced myotube size, linking MSTN treatment to atrophy independent of MPS. Remarkably, MSTN + Leu and MSTN + HMB myotubes had similar Akirin-1/Mighty and MyoD mRNA levels compared to DM/CTL myotubes. Furthermore, MSTN + Crea myotubes exhibited a 36% (p < 0.05) and 86% (p < 0.001) increase in Akirin-1/Mighty mRNA compared to DM/CTL and MSTN-only treated myotubes, respectively. Conclusions Leu, HMB and Crea may reduce MSTN-induced muscle fiber atrophy by influencing Akirin-1/Mighty mRNA expression patterns. Future studies are needed to examine if Leu, HMB and Crea independently or synergistically affect Akirin-1/Mighty expression, and how Akirin-1/Mighty expression mechanistically relates to skeletal muscle hypertrophy in vivo.
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Affiliation(s)
- Christopher Brooks Mobley
- School of Kinesiology, Molecular and Applied Sciences Laboratory, Auburn University, 301 Wire Road, Office 286, Auburn, AL 36849, USA
| | - Carlton D Fox
- School of Kinesiology, Molecular and Applied Sciences Laboratory, Auburn University, 301 Wire Road, Office 286, Auburn, AL 36849, USA
| | - Brian S Ferguson
- School of Kinesiology, Molecular and Applied Sciences Laboratory, Auburn University, 301 Wire Road, Office 286, Auburn, AL 36849, USA
| | - Rajesh H Amin
- Harrison School of Pharmacy, Auburn University, Auburn, AL, USA
| | - Vincent J Dalbo
- School of Medical and Applied Sciences, Central Queensland University, Rockhampton, QLD, Australia
| | | | | | - Jacob M Wilson
- Department of Health Sciences and Human Performance, University of Tampa, Tampa, FL, USA
| | - Michael D Roberts
- School of Kinesiology, Molecular and Applied Sciences Laboratory, Auburn University, 301 Wire Road, Office 286, Auburn, AL 36849, USA
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27
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Stefanetti RJ, Lamon S, Wallace M, Vendelbo MH, Russell AP, Vissing K. Regulation of ubiquitin proteasome pathway molecular markers in response to endurance and resistance exercise and training. Pflugers Arch 2014; 467:1523-1537. [DOI: 10.1007/s00424-014-1587-y] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2014] [Revised: 07/02/2014] [Accepted: 07/24/2014] [Indexed: 12/30/2022]
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28
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Brown LD, Thorn SR, O'Meara MC, Lavezzi JR, Rozance PJ. A physiological increase in insulin suppresses muscle-specific ubiquitin ligase gene activation in fetal sheep with sustained hypoglycemia. Physiol Rep 2014; 2:2/6/e12045. [PMID: 24944291 PMCID: PMC4208658 DOI: 10.14814/phy2.12045] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Decreased glucose transfer to the fetus is characteristic of pregnancies complicated by maternal under nutrition and placental insufficiency. Chronic experimental restriction of glucose transfer to the sheep fetus for the final 40% of gestation with a maternal insulin infusion (HG fetuses) results in fetal hypoglycemia, hypoinsulinemia, and decreased rates of fetal growth and protein accretion compared to controls (CON). Lower rates of fetal protein accretion are due to increased fetal protein breakdown and not decreased protein synthesis. However, the specific skeletal muscle pathways responsible for increased protein breakdown have not been determined. Nor has it been determined if low fetal glucose or insulin concentrations are more important for regulating these skeletal muscle protein breakdown pathways. We tested whether chronic restriction of glucose transfer to the fetus increased the ubiquitin-proteosome pathway or autophagy-lysosome pathway in fetal sheep skeletal muscle and found no evidence for an increase in the autophagy-lysosome pathway. However, HG fetuses had increase mRNA expression of MaFBx1 (twofold, P < 0.01) and a trend for increased mRNA expression of MuRF1 (P = 0.08) compared to CON. A subset of chronically hypoglycemic fetuses received an isoglycemic insulin infusion for the final 7 days of the maternal insulin infusion (HG + INS fetuses) and had MaFBx1 and MuRF1 mRNA concentrations similar to CON fetuses. These results demonstrate that fetuses exposed to sustained hypoglycemia have decreased protein accretion due to activation of the skeletal muscle ubiquitin-proteosome pathway and that a fetal hyperinsulinemic clamp can suppress this pathway even in the context of continued hypoglycemia.
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Affiliation(s)
- Laura D Brown
- Perinatal Research Center, Department of Pediatrics, University of Colorado Denver, Aurora, Colorado, USA Center for Women's Health Research, University of Colorado Denver, University of Colorado School of Medicine, Aurora, Colorado, USA
| | - Stephanie R Thorn
- Perinatal Research Center, Department of Pediatrics, University of Colorado Denver, Aurora, Colorado, USA Center for Women's Health Research, University of Colorado Denver, University of Colorado School of Medicine, Aurora, Colorado, USA
| | - Meghan C O'Meara
- Perinatal Research Center, Department of Pediatrics, University of Colorado Denver, Aurora, Colorado, USA
| | - Jinny R Lavezzi
- Perinatal Research Center, Department of Pediatrics, University of Colorado Denver, Aurora, Colorado, USA
| | - Paul J Rozance
- Perinatal Research Center, Department of Pediatrics, University of Colorado Denver, Aurora, Colorado, USA Center for Women's Health Research, University of Colorado Denver, University of Colorado School of Medicine, Aurora, Colorado, USA
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29
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Stefanetti RJ, Lamon S, Rahbek SK, Farup J, Zacharewicz E, Wallace MA, Vendelbo MH, Russell AP, Vissing K. Influence of divergent exercise contraction mode and whey protein supplementation on atrogin-1, MuRF1, and FOXO1/3A in human skeletal muscle. J Appl Physiol (1985) 2014; 116:1491-502. [PMID: 24458747 DOI: 10.1152/japplphysiol.00136.2013] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Knowledge from human exercise studies on regulators of muscle atrophy is lacking, but it is important to understand the underlying mechanisms influencing skeletal muscle protein turnover and net protein gain. This study examined the regulation of muscle atrophy-related factors, including atrogin-1 and MuRF1, their upstream transcription factors FOXO1 and FOXO3A and the atrogin-1 substrate eIF3-f, in response to unilateral isolated eccentric (ECC) vs. concentric (CONC) exercise and training. Exercise was performed with whey protein hydrolysate (WPH) or isocaloric carbohydrate (CHO) supplementation. Twenty-four subjects were divided into WPH and CHO groups and completed both single-bout exercise and 12 wk of training. Single-bout ECC exercise decreased atrogin-1 and FOXO3A mRNA compared with basal and CONC exercise, while MuRF1 mRNA was upregulated compared with basal. ECC exercise downregulated FOXO1 and phospho-FOXO1 protein compared with basal, and phospho-FOXO3A was downregulated compared with CONC. CONC single-bout exercise mediated a greater increase in MuRF1 mRNA and increased FOXO1 mRNA compared with basal and ECC. CONC exercise downregulated FOXO1, FOXO3A, and eIF3-f protein compared with basal. Following training, an increase in basal phospho-FOXO1 was observed. While WPH supplementation with ECC and CONC training further increased muscle hypertrophy, it did not have an additional effect on mRNA or protein levels of the targets measured. In conclusion, atrogin-1, MuRF1, FOXO1/3A, and eIF3-f mRNA, and protein levels, are differentially regulated by exercise contraction mode but not WPH supplementation combined with hypertrophy-inducing training. This highlights the complexity in understanding the differing roles these factors play in healthy muscle adaptation to exercise.
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Affiliation(s)
- Renae J Stefanetti
- Centre for Physical Activity and Nutrition, School of Exercise and Nutrition Sciences, Deakin University, Burwood, Australia
| | - Séverine Lamon
- Centre for Physical Activity and Nutrition, School of Exercise and Nutrition Sciences, Deakin University, Burwood, Australia
| | - Stine K Rahbek
- Section of Sport Science, Department of Public Health, Aarhus University, Aarhus, Denmark; and
| | - Jean Farup
- Section of Sport Science, Department of Public Health, Aarhus University, Aarhus, Denmark; and
| | - Evelyn Zacharewicz
- Centre for Physical Activity and Nutrition, School of Exercise and Nutrition Sciences, Deakin University, Burwood, Australia
| | - Marita A Wallace
- Centre for Physical Activity and Nutrition, School of Exercise and Nutrition Sciences, Deakin University, Burwood, Australia
| | - Mikkel H Vendelbo
- Department of Internal Medicine and Endocrinology, Aarhus University Hospital, Aarhus, Denmark
| | - Aaron P Russell
- Centre for Physical Activity and Nutrition, School of Exercise and Nutrition Sciences, Deakin University, Burwood, Australia
| | - Kristian Vissing
- Section of Sport Science, Department of Public Health, Aarhus University, Aarhus, Denmark; and
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