Figure 3.

Effects of histone methyltransferase on H3K9me1, H3K9me2, H3K9me3, CuZn-SOD, and Mn-SOD expression in placental trophoblasts. To determine if H3K9 methylation regulates CuZn-SOD and Mn-SOD expression in placental trophoblasts under oxidative stress condition, HTR-8/SVneo cells were cultured under 2%O2 treated with or without BIX01294 (5µM) in culture for 24 hours. BIX01294 is an inhibitor of histone methyltransferase. Expression of H3K9me1, H3K9me2, H3K9me3, CuZn-SOD and Mn-SOD were then evaluated. (A) Expression of H3K9me1, H3K9me2, and H3K9me3 were significantly upregulated in cells cultured under 2%O2 alone but no change (H3K9me1 and H3K9me3) or reduced (H3K9me2) in cells treated with BIX01294. In contrast, expression of CuZn-SOD and Mn-SOD were downregulated in cells cultured under 2%O2 alone but increased in cells treated with BIX01294. (B) The bar graphs show relative expression for H3K9me1, H3K9me2, H3K9me3, CuZn-SOD, and Mn-SOD after normalized by β-actin expression in each sample, mean ± SE from 5 independent experiments. *p<0.05 and **p<0.01: Cells cultured under 2% vs. 21%O2; #p<0.05 and ##p<0.01: BIX +2%O2 vs. 2%O2. These results suggest that antioxidant CuZn-SOD and Mn-SOD expression are regulated by methylation status of H3K9 in placental trophoblasts.