Novel role of NF-κB-p65 in antioxidant homeostasis in human kidney-2 cells

George LE, Lokhandwala MF, Asghar M. Novel role of NF-kappa B-p65 in antioxidant homeostasis in human kidney-2 cells. Am J Physiol Renal Physiol 302: F1440-F1446, 2012. First published March 7, 2012; doi:10.1152/ajprenal.00006.2012.-Nuclear factor-kappa B (NF-kappa B) plays a role in inflammation. However, we recently reported an association between NF-kappa B and antioxidant enzymes in renal proximal tubules of exercise-trained rats, suggesting its role in antioxidant homeostasis (George L, Lokhandwala MF, Asghar M. Am J Physiol Renal Physiol 297: F1174-F1180, 2009). A direct role of NF-kappa B in antioxidant homeostasis in renal cells has not been elucidated and warrants investigation. Therefore, we examined whether NF-kappa B has a direct role in antioxidant homeostasis and redox balance in human kidney-2 cells overexpressing NF-kappa B-p65 and compared them with the cells overexpressing Nrf-2, a well-known transcription factor involved in antioxidant homeostasis. The ability of NF-kappa B-p65 to increase antioxidant enzymes, to reduce reactive oxygen species (ROS), and to rescue ROS-induced renal dopamine D1 receptor dysfunction, was studied. The transcription activity of NF-kappa B-p65 and Nrf-2, measured as luciferase reporter activity, increased in cells overexpressing these nuclear factors. The levels of mRNA and activity of glutathione peroxidase as well as the protein levels of superoxide dismutase-1 and glutamylcystein transferase were increased in cells overexpressing NF-kappa B-p65 and Nrf-2. Furthermore, the levels of ROS decreased and D1 receptor agonist SKF38393-mediated [S-35]GTP gamma S binding (index of D1 receptor function) increased in the presence of hydrogen peroxide in cells overexpressing NF-kappa B-p65 and Nrf-2. These results suggest a direct role of NF-kappa B-p65 in antioxidant homeostasis, contributing to redox balance in renal cells.