Tan, K.P., Yang, M. and Ito, S.
Notes: The authors explored the role that nuclear factor (erythroid 2-like) factor 2 (Nrf2) may have in mitigating the cytotoxic effects of bile acids on cells. A reporter vector was constructed using the core sequence of antioxidant reporter element (ARE) sythnesized by annealing two complementary oligonucleotides with Kpn1 and BglII at the 5’ and 3’ ends, respectively, and ligated into the same restriction sites of the pGL3-Promoter Vector (designated pGL3_ARE). To ensure specificity for the experiments, three point mutations were introduced into the ARE sequence (designated pGL3_mARE). To create HepG2 cells that stably expressed human Na(+)-taurocholate co-transporting polypeptide (NTCP), the cDNA clone of NTCP was subcloned into pTargeT™ Mammalian Expression Vector via the NotI site and selected using 500μg/ml G-418. The stable clones or standard HepG2 cells were transiently transfected with 0.1µg of pGL3_ARE or pGL3_mARE, 0.02µg of the control reporter pRL-TK Vector, with or without Nrf2 or dominant negative Nrf2 expression constructs. After overnight transfection, the cells were treated with bile acids for 16–18 hours and luciferase activities determined using the Dual-Luciferase® Reporter Assay System. Each experiment was done in triplicate and repeated at least two times. (3691)