Research Paper Volume 11, Issue 23 pp 11329—11346

Figure 5. MKP-1 is an Nrf2 target gene. (A) Knockdown of Nrf2 reduced the expression of MKP-1 in A549 cells. siNrf2-C27 cells derived from A549 cells stably expressed siRNA against Nrf2. (a) mRNA levels of MKP-1 in siNrf2-C27 and siGFP-C5 cells were determined by RT-PCR. The level of 18S rRNA was used as internal control. The value for siCon cells was set at 100%. Data are presented as the mean ± SD of triplicate experiments. (b) MKP-1 protein expression in siNrf2-C27 and siGFP-C5 cells was determined by Western immunoblotting with anti-MKP-1. The relative levels of MKP-1 normalized to actin are shown above each lane. The value for siGFP-C5 cells was set at 1. (B) Knockdown of Nrf2 decreased the mRNA and protein levels of MKP-1 in H460 cells. H460 cells were transiently transfected with siRNA against Nrf2. (a) Total RNAs were harvested 24 h later. The mRNA levels of Nrf2 and MKP-1 were measured by RT-PCR. The level of 18S rRNA was used as internal control. The value for scrambled siRNA was set at 100%. (b) MKP-1 protein expression in cells transfected with scrambled siRNA or Nrf2-siRNA cells was determined by Western immunoblotting with anti-MKP-1. The relative levels of MKP-1 normalized to actin are shown above each lane. The value for scrambled siRNA-transfected cells was set at 1. Blots in 5Ab and 5Bb are representative at least three separate experiments. Data in 5Aa and 5Ba are presented as the mean ± SD of triplicate experiments (*p <0.05, **p <0.01).