HIF-1α overexpression increases Nox2 expression and activity. A: Deferoxamine (1 mM; DFO) treatment for 20 h increases HIF-1α accumulation in PC12 cells. Top part, representative HIF-1α immunoblot. Bottom part, densitometric analysis of HIF-1α protein levels normalized to tubulin levels and expressed as percent change from control (C). B–D: DFO increases HIF-1-dependent gene expression (B) Nox2 mRNA expression (C) and Nox enzyme activity (D). E: PC12 cells were transfected with 1 µg of either basic vector (pBS) or HIF-1α plasmid (HA3-HIF-1α). Top part, representative HIF-1α immunoblot. Bottom part, densitometric analysis of HIF-1α protein levels normalized to tubulin levels. F–H: Overexpression of HIF-1α increases HIF-1-dependent gene expression (F), Nox2 mRNA expression (G), and Nox enzyme activity (H). Mean ± SEM (n = 4) are shown; **P < 0.01 compared with control (C) or pBS.