Fig. 5.

Dexamethasone promotes proliferative responses via NADPH oxidases and hypoxia-inducible factor-1 in endothelial cells.

(A–C) Human microvascular endothelial cells (HMEC-1) were transfected with siRNA against p22phox, NOX2, NOX4 or scrambled RNA (siCtr). (A) Cells were exposed to dexamethasone (Dex, 10 nM) for 24 h or remained untreated (Ctr), and a 5-bromo-2′deoxyuridine (BrdU) incorporation assay was performed (n = 3,*p < 0.05 vs. siCtrCtr; ^#p < 0.05 vs. siCtrDex; (1-β) = 1). (B/C) HMEC-1 were seeded on matrigel for an in vitro tube formation assay and exposed to dexamethasone (Dex, 10 nM) for 6 h or remained untreated (Ctr). (B) Representative figures are shown. (C) For quantification, total tube lengths were evaluated (n = 3, *p < 0.05 vs. siCtrCtr; ^#p < 0.05 vs. siCtrDex; (1-β) = 1). (D–F) HMEC-1 were transfected with siRNA against HIF1α (siHIF1α) or with scrambled RNA (siCtr). (D/E) Cells were seeded on matrigel for an in vitro tube formation assay and exposed to dexamethasone (Dex, 10 nM) for 6 h. (D) Representative figures are shown. (E) For quantification, total tube lengths were evaluated (n = 3, *p < 0.05 vs. siCtrCtr; ^#p < 0.05 vs. siCtrDex; (1-β) = 1). (F) For BrdU incorporation assay, cells were exposed to dexamethasone (Dex, 10 nM) for 6 h or remained untreated (Ctr) (n = 3, *p < 0.05 vs. siCtrCtr; ^#p < 0.05 vs. siCtrDex; (1-β) = 1). Two-tailed Student's t-test was used in all cases.