HSPB1 promoter activity, mRNA levels, and protein expression are increased in normal rat kidney (NRK)-52E cells under oxidative stress.

NRK-52E cells were exposed to H₂O₂ (200, 400, or 600 μM) for 4 h, and (A) HSPB1 promoter activity was measured with luciferase assays, (B) HSPB1 mRNA levels were measured with polymerase chain reaction, and (C) HSPB1 protein and phospho-HSPB1 protein expression was measured with western blot analysis. (D) Densitometric analysis of HSPB1 protein expression after H₂O₂ exposure (200, 400, or 600 μM). Data are presented as means ± SEM, n = 5; *P < 0.05 vs. control cells.