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West DWD, Doering TM, Thompson JLM, Budiono BP, Lessard SJ, Koch LG, Britton SL, Steck R, Byrne NM, Brown MA, Peake JM, Ashton KJ, Coffey VG. Low responders to endurance training exhibit impaired hypertrophy and divergent biological process responses in rat skeletal muscle. Exp Physiol 2021; 106:714-725. [PMID: 33486778 DOI: 10.1113/ep089301] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2020] [Accepted: 01/19/2021] [Indexed: 12/11/2022]
Abstract
NEW FINDINGS What is the central question of this study? The extent to which genetics determines adaptation to endurance versus resistance exercise is unclear. Previously, a divergent selective breeding rat model showed that genetic factors play a major role in the response to aerobic training. Here, we asked: do genetic factors that underpin poor adaptation to endurance training affect adaptation to functional overload? What is the main finding and its importance? Our data show that heritable factors in low responders to endurance training generated differential gene expression that was associated with impaired skeletal muscle hypertrophy. A maladaptive genotype to endurance exercise appears to dysregulate biological processes responsible for mediating exercise adaptation, irrespective of the mode of contraction stimulus. ABSTRACT Divergent skeletal muscle phenotypes result from chronic resistance-type versus endurance-type contraction, reflecting the principle of training specificity. Our aim was to determine whether there is a common set of genetic factors that influence skeletal muscle adaptation to divergent contractile stimuli. Female rats were obtained from a genetically heterogeneous rat population and were selectively bred from high responders to endurance training (HRT) or low responders to endurance training (LRT; n = 6/group; generation 19). Both groups underwent 14 days of synergist ablation to induce functional overload of the plantaris muscle before comparison to non-overloaded controls of the same phenotype. RNA sequencing was performed to identify Gene Ontology biological processes with differential (LRT vs. HRT) gene set enrichment. We found that running distance, determined in advance of synergist ablation, increased in response to aerobic training in HRT but not LRT (65 ± 26 vs. -6 ± 18%, mean ± SD, P < 0.0001). The hypertrophy response to functional overload was attenuated in LRT versus HRT (20.1 ± 5.6 vs. 41.6 ± 16.1%, P = 0.015). Between-group differences were observed in the magnitude of response of 96 upregulated and 101 downregulated pathways. A further 27 pathways showed contrasting upregulation or downregulation in LRT versus HRT in response to functional overload. In conclusion, low responders to aerobic endurance training were also low responders for compensatory hypertrophy, and attenuated hypertrophy was associated with differential gene set regulation. Our findings suggest that genetic factors that underpin aerobic training maladaptation might also dysregulate the transcriptional regulation of biological processes that contribute to adaptation to mechanical overload.
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Affiliation(s)
- Daniel W D West
- Department of Physiology and Membrane Biology, University of California Davis, Davis, California, USA.,Toronto Rehabilitation Institute, Toronto, Ontario, Canada.,Faculty of Kinesiology and Physical Education, University of Toronto, Toronto, Ontario, Canada
| | - Thomas M Doering
- Faculty of Health Sciences and Medicine, Bond University, Robina, Gold Coast, Queensland, Australia.,School of Health, Medical and Applied Sciences, Central Queensland University, Rockhampton, Queensland, Australia
| | - Jamie-Lee M Thompson
- Faculty of Health Sciences and Medicine, Bond University, Robina, Gold Coast, Queensland, Australia
| | - Boris P Budiono
- School of Community Health, Charles Sturt University, Port Macquarie, New South Wales, Australia
| | - Sarah J Lessard
- Research Division, Joslin Diabetes Center, Boston, Massachusetts, USA.,Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts, USA
| | - Lauren G Koch
- Department of Physiology and Pharmacology, University of Toledo, Toledo, Ohio, USA
| | - Steven L Britton
- Department of Anesthesiology, University of Michigan, Ann Arbor, Michigan, USA
| | - Roland Steck
- Institute of Health and Biomedical Innovation, Queensland University of Technology, Brisbane, Queensland, Australia
| | - Nuala M Byrne
- School of Health Sciences, University of Tasmania, Launceston, Tasmania, Australia
| | - Matthew A Brown
- Guy's & St Thomas' NHS Foundation Trust and King's College London NIHR Biomedical Research Centre, London, UK
| | - Jonathan M Peake
- Institute of Health and Biomedical Innovation, Queensland University of Technology, Brisbane, Queensland, Australia
| | - Kevin J Ashton
- Faculty of Health Sciences and Medicine, Bond University, Robina, Gold Coast, Queensland, Australia
| | - Vernon G Coffey
- Faculty of Health Sciences and Medicine, Bond University, Robina, Gold Coast, Queensland, Australia
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