Figure 5.

LXA₄-induced HO-1 expression was dependent on PPARγ activation and Nrf2 translocation. HK-2 cells were pretreated with 10 nM LXA₄ for 12 h and transfected with (A) PPARγ siRNA or (B) Nrf2 siRNA, then exposed to H/R. mRNA and protein expression levels of HO-1 were determined using quantitative PCR and western blotting. The amount of PCR products was normalized to GAPDH to determine the relative expression ratio (mRNA expression ratio ×1/10) for each mRNA Protein expression of HO-1 was presented as HO-1/β-actin ratio for each sample. (C) HK-2 cells were pretreated with LXA₄ for 12 h, then exposed to H/R, and HO-1 activity and expression levels were quantified. HO-1 concentration in cell lysates was determined using ELISA. Data are presented as the mean ± standard deviation of 5 independent experiments. *P<0.05 vs. control group. HO-1, heme oxygenase-1; H/R, hypoxia/reoxygenation; LXA₄, lipoxin A₄; PPARγ, peroxisome proliferator-activated receptor-γ; siRNA, small interfering RNA; Nrf2, nuclear factor E2-related factor 2.