title: Induction of endothelin-1 expression by oxidative stress in vascular smooth muscle cells.
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.
authors.affiliation: Division of Cardiology, University of Heidelberg, Bergheimer Str. 58, D-69115, Heidelberg, Germany. johannes_ruef@med.uni-heidelberg.de
authors.forename: J
authors.initials: J
authors.lastname: Ruef
authors.forename: M
authors.initials: M
authors.lastname: Moser
authors.forename: W
authors.initials: W
authors.lastname: Kübler
authors.forename: C
authors.initials: C
authors.lastname: Bode
mesh_terms: D000975:Antioxidants / Q000494:pharmacology; D001011:Aorta; D002478:Cells, Cultured; D003600:Cytosol / Q000201:enzymology; D015237:Dinoprost / Q000031:analogs & derivatives*; D004305:Dose-Response Relationship, Drug; D019332:Endothelin-1 / Q000096:biosynthesis* / Q000235:genetics / Q000276:immunology; D004797:Enzyme-Linked Immunosorbent Assay; D028441:F2-Isoprostanes / Q000032:analysis / Q000378:metabolism; D006801:Humans; D006861:Hydrogen Peroxide / Q000494:pharmacology; D009131:Muscle, Smooth, Vascular / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D009842:Oligopeptides / Q000494:pharmacology; D018384:Oxidative Stress; D010741:Phospholipases A / Q000032:analysis / Q000096:biosynthesis; D054467:Phospholipases A2; D011794:Quercetin / Q000494:pharmacology; D012333:RNA, Messenger / Q000032:analysis / Q000378:metabolism; D000077185:Resveratrol; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013267:Stilbenes / Q000494:pharmacology
chemical_list: D000975:Antioxidants; D019332:Endothelin-1; D028441:F2-Isoprostanes; D009842:Oligopeptides; D012333:RNA, Messenger; D013267:Stilbenes; C076213:PD 142893; C075750:8-epi-prostaglandin F2alpha; D011794:Quercetin; D015237:Dinoprost; D006861:Hydrogen Peroxide; D010741:Phospholipases A; D054467:Phospholipases A2; D000077185:Resveratrol