Fig. 6.

ERK1 MAPK may be not involved in H₂O₂-induced NOX5-S expression. Transfection of ERK1 siRNA and control siRNA was carried out with Lipofectamine 2000. After a 4-h transfection, the transfection medium was replaced with regular medium. Twenty-four hours later, the transfectants were exposed to H₂O₂ (10⁻¹³ M) in fresh medium for an additional 48 h. A, knockdown of ERK1 had no effect on H₂O₂-induced NOX5 mRNA levels. B, knockdown of ERK1 had no effect on H₂O₂-induced increase in thymidine incorporation. The data suggest that ERK1 may not be involved in H₂O₂-induced increase in NOX5-S expression and in cell proliferation. n = 3, ANOVA, **, P < 0.01, compared with control siRNA group; #, P < 0.05, ##, P < 0.01, compared with control siRNA plus H₂O₂ group.