Leucine induces myofibrillar protein accretion in cultured skeletal muscle through mTOR dependent and -independent control of myosin heavy chain mRNA levels

Journal article


Haegens, Astrid, Schols, Annemie M. J. W., van Essen, Anon L., van Loon, Luc J. C. and Langen, Ramon C.. (2012). Leucine induces myofibrillar protein accretion in cultured skeletal muscle through mTOR dependent and -independent control of myosin heavy chain mRNA levels. Molecular Nutrition and Food Research. 56(5), pp. 741 - 752. https://doi.org/10.1002/mnfr.201100695
AuthorsHaegens, Astrid, Schols, Annemie M. J. W., van Essen, Anon L., van Loon, Luc J. C. and Langen, Ramon C.
Abstract

Scope: Nutritional intervention during muscle wasting aims to attenuate net muscle protein loss. Branched chain amino acids, especially leucine, are able to stimulate the anabolic mammalian target of rapamycin (mTOR) signalling cascade and protein synthesis. It has been suggested that muscle myofibrillar protein expression is more responsive to amino acid supplementation compared to cytoplasmic proteins, although accretion of myofibrillar proteins has not extensively been investigated. We hypothesized that leucine specifically increases myofibrillar protein synthesis in skeletal muscle. Methods and results: This hypothesis was investigated in C2C12 skeletal muscle cells using physiologically relevant culture conditions. Leucine supplementation specifically increased myofibrillar protein accretion, including myosin heavy chain-slow and -fast and myosin light chain 1 and -3 in C2C12 cells. Neither total protein content, nor de novo protein synthesis was affected, despite leucine-induced increased 4E-BP1 and S6K1 phosphorylation. Leucine supplementation did not affect myogenesis, measured by creatine kinase activity and myoblast fusion, either. Remarkably, leucine-induced increased myofibrillar protein accretion was accompanied by elevated MyHC mRNA levels, which involved mTOR-dependent and -independent regulation of MyHC-4 and MyHC-7 gene-expression, respectively. Conclusion: This study clearly demonstrates myofibrillar and not generic protein accretion in skeletal muscle following leucine supplementation, and suggests this involves pre-translational control of MyHC expression by leucine.

Year2012
JournalMolecular Nutrition and Food Research
Journal citation56 (5), pp. 741 - 752
PublisherWiley - V C H Verlag GmbH & Co. KGaA
ISSN1613-4125
Digital Object Identifier (DOI)https://doi.org/10.1002/mnfr.201100695
Scopus EID2-s2.0-84861684284
Page range741 - 752
Research GroupMary MacKillop Institute for Health Research
Publisher's version
File Access Level
Controlled
Place of publicationGermany
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