Vascular endothelial growth factor-mediated induction of manganese superoxide dismutase occurs through redox-dependent regulation of forkhead and IkappaB/NF-kappaB

J Biol Chem. 2004 Oct 15;279(42):44030-8. doi: 10.1074/jbc.M408285200. Epub 2004 Aug 11.


The mitochondrial antioxidant manganese superoxide dismutase (Mn-SOD) plays a critical cytoprotective role against oxidative stress. Vascular endothelial growth factor (VEGF) was shown previously to induce expression of Mn-SOD in endothelial cells by a NADPH oxidase-dependent mechanism. The goal of the current study was to determine the transcriptional mechanisms underlying this phenomenon. VEGF resulted in protein kinase C-dependent phosphorylation of IkappaB and subsequent translocation of p65 NF-kappaB into the nucleus. Overexpression of constitutively active IkappaB blocked VEGF stimulation of Mn-SOD. In transient transfection assays, VEGF increased Mn-SOD promoter activity, an effect that was dependent on a second intronic NF-kappaB consensus motif. In contrast, VEGF-mediated induction of Mn-SOD was enhanced by the phosphatidylinositol 3-kinase (PI3K) inhibitor LY294002 and by dominant negative Akt and was decreased by constitutively active Akt. Overexpression of a constitutively active (phosphorylation-resistant) form of FKHRL1 (TMFKHRL1) resulted in increased Mn-SOD expression, suggesting that the negative effect of PI3K-Akt involves attenuation of forkhead activity. In co-transfection assays, the Mn-SOD promoter was transactivated by TMFKHRL1. Flavoenzyme inhibitor, diphenyleneiodonium (DPI), and antisense oligonucleotides against p47phox (AS-p47phox) inhibited VEGF stimulation of IkappaB/NF-kappaB and forkhead phosphorylation, supporting a role for NADPH oxidase activity in both signaling pathways. Like VEGF, hepatocyte growth factor (HGF) activated the PI3K-Akt-forkhead pathway. However, HGF-PI3K-Akt-forkhead signaling was insensitive to diphenyleneiodonium and AS-p47phox. Moreover, HGF failed to induce phosphorylation of IkappaB/NF-kappaB or nuclear translocation of NF-kappaB and had no effect on Mn-SOD expression. Together, these data suggest that VEGF is uniquely coupled to Mn-SOD expression through growth factor-specific reactive oxygen species (ROS)-sensitive positive (protein kinase C-NF-kappaB) and negative (PI3K-Akt-forkhead) signaling pathways.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Active Transport, Cell Nucleus
  • Cell Line
  • Cells, Cultured
  • Coronary Vessels
  • Endothelium, Vascular / cytology
  • Endothelium, Vascular / enzymology*
  • Enzyme Induction / drug effects
  • Forkhead Transcription Factors
  • Humans
  • I-kappa B Proteins / metabolism*
  • NADPH Oxidases / metabolism
  • NF-kappa B / antagonists & inhibitors
  • NF-kappa B / metabolism*
  • Nuclear Proteins / metabolism*
  • Oxidation-Reduction
  • Oxidative Stress / physiology
  • Phosphorylation
  • Superoxide Dismutase / biosynthesis*
  • Transcription Factors / metabolism*
  • Umbilical Veins


  • Forkhead Transcription Factors
  • I kappa B beta protein
  • I-kappa B Proteins
  • NF-kappa B
  • Nuclear Proteins
  • Transcription Factors
  • Superoxide Dismutase
  • NADPH Oxidases