The effect of eicosapentaenoic and docosahexaenoic acid on protein synthesis and breakdown in murine C2C12 myotubes.
Biochem Biophys Res Commun. 2013 Feb 21. Kamolrat T, Gray SR.
Eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) have been found to stimulate protein synthesis with little information regarding the effects on protein breakdown. Furthermore whether there are distinct effects of EPA and DHA remains to be established. The aim of the current study was to determine the distinct effects of EPA and DHA on protein synthesis, protein breakdown and signalling pathways in C2C12 myotubes.
Fully differentiated C2C12 cells were incubated for 24h with 0.1% ethanol (control), 50μM EPA or 50μM DHA prior to experimentation. After serum (4h) and amino acid (1h) starvation cells were stimulated with 2mM l-leucine and protein synthesis measured using 3H-labelled phenylalanine. Protein breakdown was measured using 3H-labelled phenylalanine and signalling pathways (Akt, mTOR, p70S6k, 4EBP1, rps6 and FOXO3a) via Western blots.
Data revealed that after incubation with EPA protein synthesis was 25% greater (P<0.05) compared to the control cells, with no effect of DHA. Protein breakdown was 22% (P<0.05) lower, compared to control cells, after incubation with EPA, with no effect of DHA. Analysis of signalling pathways revealed that both EPA and DHA incubation increased (P<0.05) p70s6k phosphorylation, EPA increased (P<0.05) FOXO3a phosphorylation, with no alteration in other signalling proteins. The current study has demonstrated distinct effects of EPA and DHA on protein metabolism with EPA showing a greater ability to result in skeletal muscle protein accretion.