title: Rho protein inhibition blocks cyclooxygenase-2 expression by proinflammatory mediators in endothelial cells.
abstract: Rho proteins participate in the regulation of inflammatory gene expression in endothelial cells. We made use of Clostridium difficile toxin B-10643 (TcdB-10463) which inhibites RhoA/Rac1/Cdc42 to analyze their role in expression and regulation of cyclooxygenase-2 (COX-2) in endothelial cells (EC). Pretreatment of EC with TcdB-10643 prevented lipopolysaccharide (LPS)-or tumor necrosis factor-alpha (TNFalpha)-related COX-2 expression but had no effect on COX-1 protein levels. TcdB-10463 preincubation suppressed LPS-dependent nuclear factor-kappaB activation (NF-kappaB). Rho inhibition did not affect COX-1 activity. Inactivation of Rho proteins before LPS stimulation blocked arachidonic acid (AA)-, thrombin-, and Escherichia coli hemolysin (HlyA)-dependent release of COX-2-related 6-ketoprostaglandin F(1alpha), (6k-PGF(1alpha)). In contrast, Rho inhibition did not affect COX-2-dependent 6k-PGF(1alpha) liberation when TcdB-10643 was added 10 h after LPS or TNFalpha stimulation of EC. Therefore, RhoA/Rac1/Cdc42 contribute to NF-kappaB-dependent LPS- and TNFalpha-induced expression of PGHS-2 in EC but had no effect on the activity of expressed COX-1 and COX-2.
authors.affiliation: Charité, Department of Internal Medicine, Humboldt-University, Berlin, Germany.
authors.forename: Bernd
authors.initials: B
authors.lastname: Schmeck
authors.forename: Marco
authors.initials: M
authors.lastname: Brunsch
authors.forename: Joachim
authors.initials: J
authors.lastname: Seybold
authors.forename: Matthias
authors.initials: M
authors.lastname: Krüll
authors.forename: Christoph v
authors.initials: Cv
authors.lastname: Eichel-Streiber
authors.forename: Norbert
authors.initials: N
authors.lastname: Suttorp
authors.forename: Stefan
authors.initials: S
authors.lastname: Hippenstiel
mesh_terms: D015121:6-Ketoprostaglandin F1 alpha / Q000032:analysis; D000818:Animals; D051545:Cyclooxygenase 1; D051546:Cyclooxygenase 2; D052246:Cyclooxygenase 2 Inhibitors; D016861:Cyclooxygenase Inhibitors; D042783:Endothelial Cells; D004730:Endothelium, Vascular / Q000166:cytology*; D005786:Gene Expression Regulation; D006801:Humans; D018836:Inflammation Mediators / Q000494:pharmacology*; D007527:Isoenzymes / Q000096:biosynthesis*; D008070:Lipopolysaccharides / Q000494:pharmacology; D008565:Membrane Proteins; D011451:Prostaglandin-Endoperoxide Synthases / Q000096:biosynthesis*; D011453:Prostaglandins / Q000096:biosynthesis; D013552:Swine; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology; D014471:Umbilical Veins / Q000166:cytology; D020741:rho GTP-Binding Proteins / Q000037:antagonists & inhibitors / Q000502:physiology*
chemical_list: D052246:Cyclooxygenase 2 Inhibitors; D016861:Cyclooxygenase Inhibitors; D018836:Inflammation Mediators; D007527:Isoenzymes; D008070:Lipopolysaccharides; D008565:Membrane Proteins; D011453:Prostaglandins; D014409:Tumor Necrosis Factor-alpha; D015121:6-Ketoprostaglandin F1 alpha; D051545:Cyclooxygenase 1; D051546:Cyclooxygenase 2; C496511:PTGS1 protein, human; C496540:PTGS2 protein, human; D011451:Prostaglandin-Endoperoxide Synthases; D020741:rho GTP-Binding Proteins