Fig. 5

Blocking STAT3 activation with Stattic, a STAT3 inhibitor, prevents GDF11 mediated atrophy in vitro. A Bright-field images of myotubes treated with rGDF11 (50ng/ml), with or without STAT3 inhibitor Stattic for 48 h. Scale bars = 50 μm. The fiber widths were measured and calculated (right panel). B Myotubes treated with rGDF11 then with Stattic for 48h were used for Western blot analysis with antibodies against iNOS, pY-STAT3, total STAT3, socs3, and GAPDH. C Total protein content of rGDF11-treated myotubes, with or without STAT3 inhibitor Stattic for 48 h. D NO levels were measured in supernatant from the myotubes described in the panel. E Representative western blotting images of ubiquitin from myotubes. F Protein expression of trim63, fbx32, and foxo1 in myotubes treated with rGDF11 then with Stattic for 48h. G Representative Western blots of phosphorylation and total STAT3 from myotubes treated with rGDF11, siALK5, or AcvRIIb. Data presented as mean ± SEM. Versus vehicle control, *P < 0.05, **P < 0.01, ***P < 0.001; versus rGDF11 control, ^#P < 0.05, ^##P < 0.01, ^###P < 0.001; n=3