LXRα mediates RSV-induced CYP7A1 expression in HepG2 cells. (A) HepG2 cells were pre-incubated with vehicle or GGPP (10 μM) for 2 h, followed by RSV (50 μM) for an additional 24 h. Cellular lysates were subjected to quantitative RT-PCR to determine the mRNA levels of CYP7A1. (B) HepG2 cells were incubated with RSV (50 μM) for different times. (C) HepG2 cells were incubated with RSV (0, 25, 50 and 100 μM) for 12 h. The nuclear protein lysates were isolated and subjected to ELISA-based assay to determine the LXR transcriptional activity. The results are represented as the means ± SD of 3 individual experiments. Asterisks, significantly different from 0 hour or control ( P < 0.05).