2134/38182
Kathryn Aguilar-Agon
Kathryn
Aguilar-Agon
Andrew Capel
Andrew
Capel
Neil Martin
Neil
Martin
Darren J. Player
Darren J.
Player
Mark Lewis
Mark
Lewis
Mechanical loading stimulates hypertrophy in tissue-engineered skeletal muscle: Molecular and phenotypic responses
Loughborough University
2019
Hypertrophy
mTORC1
Myotubes
Skeletal muscle
Tissue engineering
Medical and Health Sciences not elsewhere classified
2019-07-02 13:51:10
Journal contribution
https://repository.lboro.ac.uk/articles/journal_contribution/Mechanical_loading_stimulates_hypertrophy_in_tissue-engineered_skeletal_muscle_Molecular_and_phenotypic_responses/9618776
Mechanical loading of skeletal muscle results in molecular and phenotypic adaptations typified by enhanced muscle size. Studies on humans are limited by the need for repeated sampling, and studies on animals have methodological and ethical limitations. In this investigation, three-dimensional skeletal muscle was tissue-engineered utilizing the murine cell line C2C12, which bears resemblance to native tissue and benefits from the advantages of conventional in vitro experiments. The work aimed to determine if mechanical loading induced an anabolic hypertrophic response, akin to that described in vivo after mechanical loading in the form of resistance exercise. Specifically, we temporally investigated candidate gene expression and Akt-mechanistic target of rapamycin 1 signalling along with myotube growth and tissue function. Mechanical loading (construct length increase of 15%) significantly increased insulin-like growth factor-1 and MMP-2 messenger RNA expression 21 hr after overload, and the levels of the atrophic gene MAFbx were significantly downregulated 45 hr after mechanical overload. In addition, p70S6 kinase and 4EBP-1 phosphorylation were upregulated immediately after mechanical overload. Maximal contractile force was augmented 45 hr after load with a 265% increase in force, alongside significant hypertrophy of the myotubes within the engineered muscle. Overall, mechanical loading of tissue-engineered skeletal muscle induced hypertrophy and improved force production.