Fig. 3. p90RSK was involved in TGF-β1-induced ECM accumulation. A: Human lung fibroblasts were treated with increasing concentrations of FMK for 1 hour and then incubated with TGF-β1 (2 ng/ml) for 24 hours. Protein levels were assessed by immunoblotting with specific antibodies against collagen III, fibronectin, p-p90RSK, p90RSK, and tubulin. Bar graphs present the densitometric results of Western blot bands. ANOVA: *, p<0.05; **, p<0.01 versus CON. ^†, p<0.05, ^††, p<0.01 versus TGF-β1 treated. B: Fibroblasts were transduced Ad-DN-RSK or Ad-LacZ for 1 day and then treated with TGF-β1 (2 ng/ml) for 24 hours. Expression levels of collagen III, fibronectin, p90RSK and tubulin were assessed by Western blotting. Bar graphs present the densitometric results of Western blot bands. ANOVA: *, p<0.05; **, p<0.01 versus CON. ^†, p<0.05, ^††, p<0.01 versus TGF-β1 treated. C: Fibroblasts were treated with 10 µM FMK in the presence of TGF-β1 (2 ng/ml) for 6 hours. The mRNA levels of fibronectin and PAI-1 were determined by RT-qPCR. Relative expression levels were normalized versus GAPDH. Results are presented as the means±SDs of three independent experiments that produced similar results. *: p<0.05; **: p<0.01.