Fig. 7.

NADPH oxidases promote dexamethasone-induced HIF1α protein levels.

(A) HMEC-1 were treated or not (Ctr) with either RU486 (RU, 500 μM) or GKT-137831 (GKT, 50 μM) for 1 h prior to treatment with dexamethasone (Dex, 10 nM) for 4 h. Western blot analyses were performed using an antibody against HIF1α. β-Actin served as loading control (n = 3; *p < 0.05 vs. Ctr; ^#p < 0.05 vs. Dex; (1-β)>0.955). Representative blots are shown. (B) HMEC-1 were transfected with siRNA against p22phox (sip22) or control siRNA (siCtr) and exposed to dexamethasone (Dex, 10 nM) for 4 h. Western blot analyses were performed using antibodies against p22phox and HIF1α. β-Actin served as loading control (n = 3; *p < 0.05 vs. siCtrDex 0 h; ^#p < 0.05 vs. siCtrDex 4 h; (1-β) = 1). Representative blots of are shown. (C/D) HMEC-1 were transfected with siCtr or siRNA against NOX4 (siN4/siNOX4) (C) or NOX2 (siN2/siNOX2) (D) and exposed to Dex (10 nM) for 4 h. Western blot analyses were performed using antibodies against NOX4, NOX2 and HIF1α. β-Actin served as loading control (n = 3; *p < 0.05 vs. siCtrDex 0 h; ^#p < 0.05 vs. siCtrDex 4 h; (1-β) = 1). Representative blots are shown. Two-tailed Student's t-test was used in all cases.