title: Hydrogen peroxide induces up-regulation of Fas in human endothelial cells.
abstract: Hydrogen peroxide (H2O2), an oxidant generated by inflammatory cells, is an important mediator of injury of endothelial cells (ECs). Here we show that H2O2 induces up-regulation of the expression of Fas, a death signal, in human ECs in culture. Flow cytometric analysis with a mAb against human Fas showed that incubation for 24 h with H2O2 induced a dose-dependent increase in the level of Fas in ECs. Coincubation with catalase, which rapidly degrades H2O2, inhibited H2O2-induced up-regulation of Fas. H2O2 also induced a dose-dependent increase in Fas mRNA level. A significant increase in Fas mRNA levels was observed from 6 h after stimulation with H2O2. Vanadate, a protein phosphatase inhibitor, significantly enhanced Fas mRNA and protein levels in H2O2-treated ECs. On the other hand, genistein, a tyrosine kinase inhibitor, inhibited H2O2-induced Fas mRNA expression. Furthermore, a flow cytometric method with propidium iodide staining and electron microscopic analysis showed that incubation with an agonistic Ab against Fas (anti-Fas IgM) induced apoptosis in H2O2-treated cells. These findings suggest that H2O2 induces up-regulation of Fas in ECs and that activation of protein tyrosine kinase may be involved in the mechanism of H2O2-induced Fas expression. Therefore, Fas-mediated apoptosis may have a pathologic role in H2O2-induced EC injury and thereby provide a new therapeutic target.
authors.affiliation: Department of Geriatric Medicine, Osaka University Medical School, Suita, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Suhara
authors.forename: K
authors.initials: K
authors.lastname: Fukuo
authors.forename: T
authors.initials: T
authors.lastname: Sugimoto
authors.forename: S
authors.initials: S
authors.lastname: Morimoto
authors.forename: T
authors.initials: T
authors.lastname: Nakahashi
authors.forename: S
authors.initials: S
authors.lastname: Hata
authors.forename: M
authors.initials: M
authors.lastname: Shimizu
authors.forename: T
authors.initials: T
authors.lastname: Ogihara
mesh_terms: D017209:Apoptosis / Q000187:drug effects / Q000276:immunology; D002478:Cells, Cultured; D004247:DNA / Q000378:metabolism; D004730:Endothelium, Vascular / Q000166:cytology / Q000187:drug effects* / Q000276:immunology*; D004791:Enzyme Inhibitors / Q000494:pharmacology; D019833:Genistein / Q000494:pharmacology; D006801:Humans; D008854:Microscopy, Electron; D010749:Phosphoprotein Phosphatases / Q000037:antagonists & inhibitors; D011505:Protein-Tyrosine Kinases / Q000037:antagonists & inhibitors; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D015854:Up-Regulation / Q000187:drug effects; D014638:Vanadates / Q000494:pharmacology; D019014:fas Receptor / Q000235:genetics* / Q000378:metabolism*
chemical_list: D004791:Enzyme Inhibitors; D012333:RNA, Messenger; D019014:fas Receptor; D014638:Vanadates; D004247:DNA; D019833:Genistein; D011505:Protein-Tyrosine Kinases; D010749:Phosphoprotein Phosphatases