Opposing roles of p47phox in basal versus angiotensin II-stimulated alterations in vascular O2- production, vascular tone, and mitogen-activated protein kinase activation

Circulation. 2004 Mar 16;109(10):1307-13. doi: 10.1161/01.CIR.0000118463.23388.B9. Epub 2004 Mar 1.

Abstract

Background: NADPH oxidase is a major source of vascular superoxide (O2-) production and is implicated in angiotensin II (Ang II)-induced oxidant stress. The p47phox subunit plays an important role in Ang II-induced oxidase activation, but its role in basal oxidase activity and vascular function is unclear.

Methods and results: Aortae from p47phox-/- and matched wild-type (WT) mice (n=9/group) were incubated ex vivo with or without Ang II (200 nmol/L, 30 minutes) and then examined for (1) NADPH-dependent O2- production, (2) endothelium-dependent and -independent vascular relaxation, and (3) activation of mitogen-activated protein kinases (MAPKs). In the absence of Ang II, p47phox-/- vessels had slightly but significantly higher (1.3+/-0.1-fold; P<0.05) NADPH-dependent O2- production than WT; impaired relaxation to acetylcholine (maximum 54+/-4% versus 80+/-3%; P<0.05), which was normalized to WT levels by the O2- scavenger tiron or by Mn(III)tetrakis(1-methyl-4-pyridyl)porphyrin pentachloride, and increased basal phosphorylation of ERK1/2, p38MAPK, and JNK compared with WT. In WT aortae, Ang II increased NADPH-dependent O2- production (2.5+/-0.5-fold; P<0.05), impaired relaxation to acetylcholine (maximum 60+/-6% versus 80+/-3%; P<0.05), and increased ERK1/2, p38MAPK, and JNK phosphorylation (P<0.05). In contrast, Ang II failed to increase O2- production, impair acetylcholine responses, or increase MAPK activation in p47phox-/- aortae.

Conclusions: p47phox plays a complex dual role in the vasculature. It inhibits basal NADPH oxidase activity but is critical for Ang II-induced vascular dysfunction via activation of NADPH oxidase.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • 1,2-Dihydroxybenzene-3,5-Disulfonic Acid Disodium Salt / pharmacology
  • Acetylcholine / pharmacology
  • Angiotensin II / pharmacology*
  • Animals
  • Aorta, Thoracic
  • Endothelium, Vascular / physiology
  • Enzyme Activation / drug effects
  • Free Radical Scavengers / pharmacology
  • In Vitro Techniques
  • JNK Mitogen-Activated Protein Kinases*
  • MAP Kinase Kinase 4
  • MAP Kinase Signaling System / drug effects
  • Metalloporphyrins / pharmacology
  • Mice
  • Mice, Knockout
  • Mitogen-Activated Protein Kinase 1 / metabolism
  • Mitogen-Activated Protein Kinase 3
  • Mitogen-Activated Protein Kinase Kinases / metabolism
  • Mitogen-Activated Protein Kinases / metabolism
  • NADPH Oxidases / metabolism
  • Nitric Oxide Donors / pharmacology
  • Nitroprusside / pharmacology
  • Oxygen / metabolism
  • Phosphoproteins / physiology*
  • Reactive Oxygen Species / metabolism
  • Vasodilation / drug effects
  • p38 Mitogen-Activated Protein Kinases

Substances

  • Free Radical Scavengers
  • Metalloporphyrins
  • Nitric Oxide Donors
  • Phosphoproteins
  • Reactive Oxygen Species
  • Angiotensin II
  • Nitroprusside
  • 1,2-Dihydroxybenzene-3,5-Disulfonic Acid Disodium Salt
  • tetrakis(N-methyl-4-pyridiniumyl)porphine manganese(III) complex
  • NADPH Oxidases
  • neutrophil cytosolic factor 1
  • JNK Mitogen-Activated Protein Kinases
  • Mitogen-Activated Protein Kinase 1
  • Mitogen-Activated Protein Kinase 3
  • Mitogen-Activated Protein Kinases
  • p38 Mitogen-Activated Protein Kinases
  • MAP Kinase Kinase 4
  • Mitogen-Activated Protein Kinase Kinases
  • Acetylcholine
  • Oxygen