Format

Send to

Choose Destination
See comment in PubMed Commons below
Nutr Res. 2014 Apr;34(4):368-74. doi: 10.1016/j.nutres.2014.02.003. Epub 2014 Feb 10.

β-Hydroxy-β-methylbutyrate facilitates PI3K/Akt-dependent mammalian target of rapamycin and FoxO1/3a phosphorylations and alleviates tumor necrosis factor α/interferon γ-induced MuRF-1 expression in C2C12 cells.

Author information

1
Department of Community Healthcare & Geriatrics, Nagoya University Graduate School of Medicine, Nagoya, Japan.
2
Department of Community Healthcare & Geriatrics, Nagoya University Graduate School of Medicine, Nagoya, Japan. Electronic address: xianwu@med.nagoya-u.ac.jp.
3
Department of Sports Medicine, Nagoya University Graduate School of Medicine, Nagoya, Japan.
4
Department of Community Healthcare & Geriatrics, Nagoya University Graduate School of Medicine, Nagoya, Japan. Electronic address: kuzuya@med.nagoya-u.ac.jp.

Abstract

β-Hydroxy-β-methylbutyrate (HMB) prevents deleterious muscle responses under pathological conditions, including tumor- and chronic steroid therapy-related muscle losses. Here, we investigated the hypothesis that HMB may modulate the balance between protein synthesis and degradation in the PI3K/Akt-mediated mammalian target of rapamycin (mTOR) and FoxO1/FoxO3a-dependent mechanisms in differentiated C2C12 muscle cells. We also tested the effect of HMB on the expression of MuRF-1 and atrogin-1 in response to the inflammatory stress. β-Hydroxy-β-methylbutyrate up-regulated phosphorylation of Akt and mTOR, and these effects were completely abolished in the presence of PI3K inhibitor LY294002. β-Hydroxy-β-methylbutyrate also up-regulated FoxO1 and FoxO3a phosphorylation, and these changes were inhibited by LY294002. Although, unexpectedly, HMB failed to reduce the expressions of atrophy-related atrogin-1 messenger RNA and the protein response to the proinflammatory cytokines tumor necrosis factor α plus interferon γ, HMB did attenuate the MuRF-1 expression. Thus, HMB appears to restore the balance between intracellular protein synthesis and proteolysis, likely via activation of the PI3K/Akt-dependent mTOR and FoxO1/FoxO3a signaling pathway and the reduction of tumor necrosis factor α/interferon γ-induced MuRF-1 expression, thereby ameliorating aging-related muscle atrophy.

KEYWORDS:

C2C12; Forkhead box class O; Phosphoinositide 3-kinase; Ubiquitin ligase; β-Hydroxy-β-methylbutyrate

PMID:
24774073
DOI:
10.1016/j.nutres.2014.02.003
[Indexed for MEDLINE]
PubMed Commons home

PubMed Commons

0 comments
How to join PubMed Commons

    Supplemental Content

    Full text links

    Icon for Elsevier Science
    Loading ...
    Support Center