FIG. 5.

Involvement of Nrf2 in EP-mediated HO-1 expression. Cells were treated for 1 h with EP at 5, 10, and 25 mM, and then harvested and subjected to cytosol/nuclear fractionation (A). Cells were transiently transfected with the ARE-luc vector (B). After incubation, cells were treated with EP (5, 10, and 25 mM) or EP (25 mM)+SB203580 (10 μM, which was pretreated 1 h before addition of EP) for 1 h. After incubation, cells were subjected to luciferase assay as described in the Materials and Methods section. Cells were transfected with scramble (siRNA) or siNrf2 (C) as described in the Materials and Methods section. After 8-h incubation with EP (25 mM), cells were harvested and subjected to western blot for HO-1 expression. Transfection efficiency was confirmed by checking Nrf2 expression. Data are presented as±SD of three independent experiments. Significance compared with control, *p<0.05 and **p<0.01; significance compared with EP alone or EP+ssiRNA, ^†p<0.05 and ^††p<0.01. ARE, antioxidant redox element; Nrf2, NF-E2-related factor 2.