Figure 5.

Inhibition of FoxO activity induces myofiber hypertrophy via increased de novo protein synthesis. A, B) Soleus and TA muscles were transfected with an empty vector or a DN FoxO expression plasmid; 4 d later, mice were injected with cycloheximide or vehicle for 6 d. Myofiber hypertrophy in soleus (A) and TA (B) muscle fibers expressing DN FoxO in vehicle-injected mice was prevented in mice injected with the protein synthesis inhibitor cycloheximide. C) Representative images and mean myotube diameter of C2C12 myotubes transfected (as myoblasts) with either DsRed or DN FoxO-DsRed and treated with vehicle or rapamycin (Rapa) for 72 h. *P < 0.05 vs. control empty vector or vehicle DsRed.