Fig. 2.

TGFβ activates STAT3 signaling in fibroblasts. a Total nuclear and cytoplasmatic levels of P-STAT3 and total STAT3 in human dermal fibroblasts stimulated for 1 h with TGFβ as analyzed by western blot (n ≥ 4 and 2 technical replicates). b–d Time-dependent changes in the levels of P-STAT3 as evaluated by b immunofluorescence staining and c quantification further confirmed by d western blot (n ≥ 5 for all). e, f Levels of P-STAT3 in fibroblasts in bleomycin-challenged mice, treated with SD-208, a selective TGFβ receptor type 1 kinase inhibitor (n ≥ 4 with 2 technical replicates for all groups) analyzed by e western blot and f its quantification. Representative blots and images (200-fold magnification; horizontal scale bar, 100 μm) are shown. Expected band size for P-STAT3 and STAT3 are 79 kDa (lower faint band) and 86 kDa (higher intense band) and the ladder represents 100 kDa. Beta-actin expected molecular weight/size is 42 kDa. Results are shown as median ± interquartile range (IQR). *P < 0.05, **P < 0.01 vs. healthy dermal fibroblasts or unstimulated/untreated control fibroblasts, or vehicle-treated, fibrotic mice, respectively