title: Thrombin induces cyclooxygenase-2 expression and prostaglandin E2 release via PAR1 activation and ERK1/2- and p38 MAPK-dependent pathway in murine macrophages.
abstract: Thrombin levels increase at sites of vascular injury and during acute coronary syndromes. It is also increased several fold by sepsis with a reciprocal decrease in the anti-thrombin III levels. In this study we investigate the effects of thrombin on the induction of cyclooxygenase-2 (COX-2) and prostaglandin (PG) production in macrophages. Thrombin-induced COX-2 protein and mRNA expression in RAW264.7 and primary cultured peritoneal macrophages. A serine proteinase, trypsin, also exerted a similar effect. The inducing effect by thrombin in macrophages was not affected by a lipopolysaccharide (LPS)-binding antibiotic, polymyxin B, excluding the possibility of LPS contamination. The increase of COX-2 expression by thrombin was functionally linked to release of PGE(2) and PGI(2) but not thromboxane A(2) into macrophage culture medium. Thrombin-induced COX-2 expression and PGE(2) production were significantly attenuated by PD98059 and SB202190 but not by SP600125, suggesting that ERK1/2 and p38 MAPK activation were involved in this process. This was supported by the observation that thrombin could directly activate ERK1/2 and p38 MAPK in macrophages. A further analysis indicated that the proteinase-activated receptor 1 (PAR1)-activating agonist induced effects similar to those induced by thrombin in macrophages and the PAR1 antagonist-SCH79797 could attenuate thrombin-induced COX-2 expression and PGE(2) release. Taken together, we provided evidence demonstrating that thrombin can induce COX-2 mRNA and protein expression and PGE(2) production in macrophages through PAR1 activation and ERK1/2 and p38 MAPK-dependent pathway. The results presented here may explain, at least in part, the possible contribution of thrombin and macrophages in these pathological conditions.
authors.affiliation: School of Medicine, Fu-Jen Catholic University, Taipei, Taiwan.
authors.forename: Huey-Ming
authors.initials: HM
authors.lastname: Lo
authors.forename: Chih-Li
authors.initials: CL
authors.lastname: Chen
authors.forename: Yih-Jeng
authors.initials: YJ
authors.lastname: Tsai
authors.forename: Pi-Hui
authors.initials: PH
authors.lastname: Wu
authors.forename: Wen-Bin
authors.initials: WB
authors.lastname: Wu
mesh_terms: D000818:Animals; D002460:Cell Line; D051546:Cyclooxygenase 2 / Q000096:biosynthesis* / Q000235:genetics; D015232:Dinoprostone / Q000378:metabolism*; D004790:Enzyme Induction / Q000187:drug effects; D004791:Enzyme Inhibitors / Q000494:pharmacology; D011464:Epoprostenol / Q000378:metabolism; D005419:Flavonoids / Q000494:pharmacology; D007093:Imidazoles / Q000494:pharmacology; D017737:Macrophages, Peritoneal / Q000378:metabolism*; D051379:Mice; D048052:Mitogen-Activated Protein Kinase 3 / Q000037:antagonists & inhibitors / Q000378:metabolism*; D011725:Pyridines / Q000494:pharmacology; D011758:Pyrroles / Q000494:pharmacology; D011799:Quinazolines / Q000494:pharmacology; D044463:Receptor, PAR-1 / Q000819:agonists / Q000378:metabolism*; D015398:Signal Transduction; D013917:Thrombin / Q000378:metabolism* / Q000494:pharmacology; D013928:Thromboxane A2 / Q000378:metabolism; D048051:p38 Mitogen-Activated Protein Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism*; D010975:Platelet Aggregation Inhibitors
chemical_list: D004791:Enzyme Inhibitors; D005419:Flavonoids; D007093:Imidazoles; C415424:N3-cyclopropyl-7-((4-(1-methylethyl)phenyl)methyl)-7H-pyrrolo(3, 2-f)quinazoline-1,3-diamine; D011725:Pyridines; D011758:Pyrroles; D011799:Quinazolines; D044463:Receptor, PAR-1; D013928:Thromboxane A2; D011464:Epoprostenol; D051546:Cyclooxygenase 2; D048052:Mitogen-Activated Protein Kinase 3; D048051:p38 Mitogen-Activated Protein Kinases; D013917:Thrombin; D015232:Dinoprostone; C090942:4-(4-fluorophenyl)-2-(4-hydroxyphenyl)-5-(4-pyridyl)imidazole; C093973:2-(2-amino-3-methoxyphenyl)-4H-1-benzopyran-4-one; D010975:Platelet Aggregation Inhibitors