title: Glutathione regulation of redox-sensitive signals in tumor necrosis factor-alpha-induced vascular endothelial dysfunction.
abstract: We investigated the regulatory role of glutathione in tumor necrosis factor-alpha (TNF-alpha)-induced vascular endothelial dysfunction as evaluated by using vascular endothelial adhesion molecule expression and monocyte-endothelial monolayer binding. Since TNF-alpha induces various biological effects on vascular cells, TNF-alpha dosage could be a determinant factor directing vascular cells into different biological fates. Based on the adhesion molecule expression patterns responding to different TNF-alpha concentrations, we adopted the lower TNF-alpha (0.2 ng/ml) to rule out the possible involvement of other TNF-alpha-induced biological effects. Inhibition of glutathione synthesis by l-buthionine-(S,R)-sulfoximine (BSO) resulted in down-regulations of the TNF-alpha-induced adhesion molecule expression and monocyte-endothelial monolayer binding. BSO attenuated the TNF-alpha-induced nuclear factor-kappaB (NF-kappaB) activation, however, with no detectable effect on AP-1 and its related mitogen-activated protein kinases (MAPKs). Deletion of an AP-1 binding site in intercellular adhesion molecule-1 (ICAM-1) promoter totally abolished its constitutive promoter activity and its responsiveness to TNF-alpha. Inhibition of ERK, JNK, or NF-kappaB attenuates TNF-alpha-induced ICAM-1 promoter activation and monocyte-endothelial monolayer binding. Our study indicates that TNF-alpha induces adhesion molecule expression and monocyte-endothelial monolayer binding mainly via activation of NF-kappaB in a glutathione-sensitive manner. We also demonstrated that intracellular glutathione does not modulate the activation of MAPKs and/or their downstream AP-1 induced by lower TNF-alpha. Although AP-1 activation by the lower TNF-alpha was not detected in our systems, we could not rule out the possible involvement of transiently activated MAPKs/AP-1 in the regulation of TNF-alpha-induced adhesion molecule expression.
authors.affiliation: Laboratory of Molecular Toxicology, Division of Environmental Health and Occupational Medicine, National Health Research Institutes, Zhunan Town, Miaoli County, Taiwan. tctsou@nhri.org.tw
authors.forename: Tsui-Chun
authors.initials: TC
authors.lastname: Tsou
authors.forename: Szu Ching
authors.initials: SC
authors.lastname: Yeh
authors.forename: Feng-Yuan
authors.initials: FY
authors.lastname: Tsai
authors.forename: Jein-Wen
authors.initials: JW
authors.lastname: Chen
authors.forename: Huai-Chih
authors.initials: HC
authors.lastname: Chiang
mesh_terms: D002478:Cells, Cultured; D004730:Endothelium, Vascular / Q000166:cytology / Q000378:metabolism / Q000503:physiopathology*; D005978:Glutathione / Q000096:biosynthesis / Q000502:physiology*; D006801:Humans; D018799:Intercellular Adhesion Molecule-1 / Q000235:genetics; D010084:Oxidation-Reduction; D011401:Promoter Regions, Genetic; D047428:Protein Kinase Inhibitors / Q000494:pharmacology; D011494:Protein Kinases / Q000187:drug effects; D014409:Tumor Necrosis Factor-alpha / Q000502:physiology*
chemical_list: D047428:Protein Kinase Inhibitors; D014409:Tumor Necrosis Factor-alpha; D018799:Intercellular Adhesion Molecule-1; D011494:Protein Kinases; D005978:Glutathione