Induction of endothelin-1 expression by oxidative stress in vascular smooth muscle cells

Cardiovasc Pathol. Nov-Dec 2001;10(6):311-5. doi: 10.1016/s1054-8807(01)00095-3.

Abstract

Atherosclerosis is based on endothelial dysfunction leading to impaired vasomotor function. This is partially due to nitric oxide (NO) depletion caused by oxidative stress. Since the vasoconstrictor endothelin-1 (ET-1) might also be involved in endothelial dysfunction, we investigated whether oxidative stress regulates ET-1 expression in vascular smooth muscle cells (VSMC). Human aortic VSMC were treated with H(2)O(2) (200 microM) for up to 8 h. mRNA expression of preproendothelin (prepro-ET) was analyzed by RT-PCR. ET-1 protein and the marker for oxidative stress, 8-isoprostane, were determined by ELISA. Activity of cytosolic phospholipase A2 (cPLA(2)) as an indicator of ET-1 autocrine activity was measured photometrically. Stimulation of VSMC with H(2)O(2) resulted in increased expression of prepro-ET mRNA after 1 h with a maximum after 6 h (fourfold), similar to treatment with angiotensin II. ET-1 protein was significantly increased by H(2)O(2) treatment with a maximum after 8 h (P<.05). This effect was inhibited by the antioxidants resveratrol (100 microM) and quercetin (50 microM). In quiesced VSMC, incubation with H(2)O(2)-conditioned medium resulted in increased cPLA(2) activity compared to the controls (P<.05). This activity was partially inhibited by the ET(A)-receptor antagonist, PD 142893 (10 microM), indicating functional ET-1 in the conditioned medium. The presence of oxidative stress in H(2)O(2)-treated VSMC was associated by significantly increased formation of 8-isoprostane (P<.05). The data indicate for the first time that oxidative stress increases ET-1 generation and autocrine ET-1 activity in VSMC, a mechanism that might contribute to endothelial dysfunction in atherosclerosis.

MeSH terms

  • Antioxidants / pharmacology
  • Aorta
  • Cells, Cultured
  • Cytosol / enzymology
  • Dinoprost* / analogs & derivatives*
  • Dose-Response Relationship, Drug
  • Endothelin-1 / biosynthesis*
  • Endothelin-1 / genetics
  • Endothelin-1 / immunology
  • Enzyme-Linked Immunosorbent Assay
  • F2-Isoprostanes / analysis
  • F2-Isoprostanes / metabolism
  • Humans
  • Hydrogen Peroxide / pharmacology
  • Muscle, Smooth, Vascular / cytology
  • Muscle, Smooth, Vascular / drug effects
  • Muscle, Smooth, Vascular / metabolism*
  • Oligopeptides / pharmacology
  • Oxidative Stress*
  • Phospholipases A / analysis
  • Phospholipases A / biosynthesis
  • Phospholipases A2
  • Quercetin / pharmacology
  • RNA, Messenger / analysis
  • RNA, Messenger / metabolism
  • Resveratrol
  • Reverse Transcriptase Polymerase Chain Reaction
  • Stilbenes / pharmacology

Substances

  • Antioxidants
  • Endothelin-1
  • F2-Isoprostanes
  • Oligopeptides
  • RNA, Messenger
  • Stilbenes
  • PD 142893
  • 8-epi-prostaglandin F2alpha
  • Quercetin
  • Dinoprost
  • Hydrogen Peroxide
  • Phospholipases A
  • Phospholipases A2
  • Resveratrol