Statins are a widely prescribed class of cholesterol lowering drugs whose use is frequently associated with muscle related ailments. A number of mechanisms have been implicated in statin-induced myotoxicity including alterations in both protein synthesis and protein degradation. The objective of the current study was to explore the mechanism(s) contributing to the statin-induced reduction in protein synthesis in the muscle-derived C2C12 cell line. Cells were treated with 10 μM simvastatin or vehicle alone for 24 h in 1% serum. Cells exposed to simvastatin exhibited reduced rates of protein synthesis as evidenced by [35S]methionine and [35S]cysteine incorporation into protein. The reduction in protein synthesis occurred with a concomitant decrease in expression and activity of eIF2B, a regulated and rate-controlling guanine nucleotide exchange factor known to affect global rates of protein synthesis. The reductions in protein synthesis and eIF2B expression were prevented by coincubation with mevalonate. Simvastatin treatment also resulted in a proteasome-sensitive reduction in the protein expression of all the subunits of the eIF2B heteropentameric complex. Finally, increased phosphorylation of the catalytic epsilon subunit at Ser535 was observed, an event consistent with an observed reduction in eIF2B activity. These results suggest that repression of eIF2B expression and activity may contribute, at least in part, to the statin-induced reduction in protein synthesis.
- mRNA translation
- HMC CoA-Reductase
- Copyright © 2010, American Journal of Physiology - Endocrinology and Metabolism