1. Rho protein inhibition blocks cyclooxygenase-2 expression by proinflammatory mediators in endothelial cells.
- Author
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Schmeck B, Brunsch M, Seybold J, Krüll M, Eichel-Streiber Cv, Suttorp N, and Hippenstiel S
- Subjects
- 6-Ketoprostaglandin F1 alpha analysis, Animals, Cyclooxygenase 1, Cyclooxygenase 2, Cyclooxygenase 2 Inhibitors, Endothelial Cells, Gene Expression Regulation, Humans, Lipopolysaccharides pharmacology, Membrane Proteins, Prostaglandins biosynthesis, Swine, Tumor Necrosis Factor-alpha pharmacology, Umbilical Veins cytology, rho GTP-Binding Proteins antagonists & inhibitors, Cyclooxygenase Inhibitors, Endothelium, Vascular cytology, Inflammation Mediators pharmacology, Isoenzymes biosynthesis, Prostaglandin-Endoperoxide Synthases biosynthesis, rho GTP-Binding Proteins physiology
- 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.
- Published
- 2003
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