Angiotensin II stimulation of NAD(P)H oxidase activity: upstream mediators

Circ Res. 2002 Sep 6;91(5):406-13. doi: 10.1161/01.res.0000033523.08033.16.


Angiotensin II (Ang II)-stimulated hypertrophy of vascular smooth muscle cells is mediated by reactive oxygen species (ROS) derived from NAD(P)H oxidases. The upstream signaling mechanisms by which Ang II activates these oxidases are unclear but may include protein kinase C, tyrosine kinases, phosphatidylinositol-3-kinase, and Rac, a small molecular weight G protein. We found that Ang II-stimulated ROS production is biphasic. The first phase occurs rapidly (peak at 30 seconds) and is dependent on protein kinase C activation. The larger second phase of ROS generation (peak at 30 minutes) requires Rac activation, because inhibition of Rac by either Clostridium difficile toxin A or dominant-negative Rac significantly inhibits Ang II-induced ROS production. Phosphatidylinositol-3-kinase inhibitors (wortmannin or LY294002) and the epidermal growth factor (EGF) receptor kinase blocker AG1478 attenuate both Rac activation and ROS generation. The upstream activator of EGF receptor transactivation, c-Src, is also required for ROS generation, because PP1, an Src kinase inhibitor, abrogates the Ang II stimulation of both responses. These results suggest that c-Src, EGF receptor transactivation, phosphatidylinositol-3-kinase, and Rac play important roles in the sustained Ang II-mediated activation of vascular smooth muscle cell NAD(P)H oxidases and provide insight into the integrated signaling mechanisms whereby Ang II stimulation leads to activation of the growth-related NAD(P)H oxidases.

Publication types

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

MeSH terms

  • Androstadienes / pharmacology
  • Angiotensin II / pharmacology*
  • Animals
  • Cells, Cultured
  • Chromones / pharmacology
  • Enzyme Inhibitors / pharmacology
  • ErbB Receptors / metabolism
  • Flow Cytometry
  • Hydrogen Peroxide / metabolism
  • Indoles / pharmacology
  • Male
  • Maleimides / pharmacology
  • Morpholines / pharmacology
  • Muscle, Smooth, Vascular / cytology
  • Muscle, Smooth, Vascular / drug effects*
  • Muscle, Smooth, Vascular / metabolism
  • NADH, NADPH Oxidoreductases / drug effects
  • NADH, NADPH Oxidoreductases / metabolism*
  • NADPH Oxidases
  • Phosphatidylinositol 3-Kinases / metabolism
  • Phosphoinositide-3 Kinase Inhibitors
  • Protein Kinase C / antagonists & inhibitors
  • Protein Kinase C / metabolism
  • Pyrazoles / pharmacology
  • Pyrimidines / pharmacology
  • Rats
  • Rats, Sprague-Dawley
  • Reactive Oxygen Species / metabolism
  • Signal Transduction / drug effects
  • Time Factors
  • Wortmannin
  • rac GTP-Binding Proteins / metabolism
  • src-Family Kinases / antagonists & inhibitors
  • src-Family Kinases / metabolism


  • 4-amino-5-(4-methylphenyl)-7-(tert-butyl)pyrazolo(3,4-d)pyrimidine
  • Androstadienes
  • Chromones
  • Enzyme Inhibitors
  • Indoles
  • Maleimides
  • Morpholines
  • Phosphoinositide-3 Kinase Inhibitors
  • Pyrazoles
  • Pyrimidines
  • Reactive Oxygen Species
  • Angiotensin II
  • 2-(4-morpholinyl)-8-phenyl-4H-1-benzopyran-4-one
  • Hydrogen Peroxide
  • NADH, NADPH Oxidoreductases
  • NADPH Oxidases
  • ErbB Receptors
  • src-Family Kinases
  • Protein Kinase C
  • rac GTP-Binding Proteins
  • bisindolylmaleimide I
  • Wortmannin