PPARα siRNA transfection decreased catalase expression and abolished beneficial effects of Wy14643 in human dermal fibroblasts.

<p><b>(a)</b> Human fibroblasts were transfected with scrambled siRNA as a negative control (NC) or siRNAs selectively targeting PPARα (100 nM) for 48 h. Cells were subjected to serum-starvation for 24 h. Levels of PPARα and catalase mRNAs were measured by qPCR. Data are presented as mean±SEM (n = 3), *<i>p</i><0.05, ***<i>p</i><0.001 vs. cells transfected with scrambled siRNA <b>(b)</b> Cultured fibroblasts were transfected with scrambled siRNA or PPARα siRNA for 48 h, and serum-starved for 24 h. Then, they were exposed to UV irradiation (100 mJ/cm²), followed by 1–100 μM Wy14643 treatment for 72 h. Levels of procollagen and MMP-1 proteins released into culture media were measured by western blotting. The bands are representative of results from three independent experiments. <b>(c)</b> Procollagen and MMP-1 mRNA expression was measured by qPCR. Data are presented as mean±SEM (n = 3), *<i>p</i><0.05, **<i>p</i><0.01 vs. UV-treated cells; #<i>p</i><0.05, ##<i>p</i><0.01 vs. NC siRNA-transfected UV-treated cells.