Fig. 4
Inhibition of PPAR-γ on the expression of PPAR-γ and ET-1 mRNA. A549 cells were incubated with 10 ng/mL TGF-β1 or 10 μM S2871 respectively while cells were pre-treated with 10 μM S2871 for 60 min before 10 ng/mL TGF-β1 stimulation for S2871 + TGF-β1 group. Then the samples were collected and analyzed by real-time qPCR, ELISA and western blotting as described previously. The relative PPAR-γ mRNA level (normalized to GAPDH mRNA) in S2871 group was significantly decreased (a) while compared to control group and the ET-1 level was significantly increased (b) (*p < 0.05). The increased expression of ET-1 mRNA (c) and protein (d) mediated by TGF-β1was enhanced by S2871 (*p < 0.05). Western blotting showed that S2871 increased the expression of phospho-P38 and phospho-Smad2 (e). The results are presented as means ± SD of 3 independent experiments performed in triplicate. (C, control group; S, S2871 group; TGF, TGF-β1 group; S + TGF, S2871 + TGF-β1 group)