title: Tissue factor pathway inhibitor 2 is induced by thrombin in human macrophages.
abstract: Tissue factor pathway inhibitor 2 (TFPI2) is a serine protease inhibitor critical for the regulation of extracellular matrix remodeling and atherosclerotic plaque stability. Previously, we demonstrated that TFPI2 expression is increased in monocytes from patients with familial combined hyperlipidemia (FCH). To gain insight into the molecular mechanisms responsible for this upregulation, we examined TFPI2 expression in THP-1 macrophages exposed to lipoproteins and thrombin. Our results showed that TFPI2 expression was not affected by treatment with very low density lipoproteins (VLDL), but was induced by thrombin (10 U/ml) in THP-1 (1.9-fold increase, p<0.001) and human monocyte-derived macrophages (2.3-fold increase, p<0.005). The specificity of the inductive effect was demonstrated by preincubation with the thrombin inhibitors hirudin and PPACK, which ablated thrombin effects. TFPI2 induction was prevented by pre-incubation with MEK1/2 and JNK inhibitors, but not by the EGF receptor antagonist AG1478. In the presence of parthenolide, an inhibitor of NFκB, but not of SR-11302, a selective AP-1 inhibitor, thrombin-mediated TFPI2 induction was blunted. Our results also show that thrombin treatment increased ERK1/2, JNK and IκBα phosphorylation. Finally, we ruled out the possibility that TFPI2 induction by thrombin was mediated by COX-2, as preincubation with a selective COX-2 inhibitor did not prevent the inductive effect. In conclusion, thrombin induces TFPI2 expression by a mechanism involving ERK1/2 and JNK phosphorylation, leading finally to NFkB activation. In the context of atherosclerosis, thrombin-induced macrophage TFPI2 expression could represent a means of avoiding excessive activation of matrix metalloproteases at sites of inflammation.
authors.affiliation: Unidad de Farmacología, Universidad de Barcelona, Spain. alegret@ub.edu
authors.forename: Jordi
authors.initials: J
authors.lastname: Pou
authors.forename: Alba
authors.initials: A
authors.lastname: Rebollo
authors.forename: Lídia
authors.initials: L
authors.lastname: Piera
authors.forename: Manuel
authors.initials: M
authors.lastname: Merlos
authors.forename: Núria
authors.initials: N
authors.lastname: Roglans
authors.forename: Juan C
authors.initials: JC
authors.lastname: Laguna
authors.forename: Marta
authors.initials: M
authors.lastname: Alegret
mesh_terms: D000590:Amino Acid Chloromethyl Ketones / Q000494:pharmacology; D000873:Anthracenes / Q000494:pharmacology; D000991:Antithrombins / Q000494:pharmacology; D015153:Blotting, Western; D002070:Butadienes / Q000494:pharmacology; D002460:Cell Line; D002478:Cells, Cultured; D052246:Cyclooxygenase 2 Inhibitors / Q000494:pharmacology; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005419:Flavonoids / Q000494:pharmacology; D015870:Gene Expression / Q000187:drug effects; D006023:Glycoproteins / Q000235:genetics / Q000378:metabolism*; D006629:Hirudins / Q000494:pharmacology; D006801:Humans; D048031:JNK Mitogen-Activated Protein Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism; D008079:Lipoproteins, VLDL / Q000494:pharmacology; D008264:Macrophages / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D020928:Mitogen-Activated Protein Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism; D016328:NF-kappa B / Q000037:antagonists & inhibitors / Q000378:metabolism; D009570:Nitriles / Q000494:pharmacology; D009578:Nitrobenzenes / Q000494:pharmacology; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012717:Sesquiterpenes / Q000494:pharmacology; D015398:Signal Transduction / Q000187:drug effects; D013449:Sulfonamides / Q000494:pharmacology; D013917:Thrombin / Q000494:pharmacology*; D013997:Time Factors
chemical_list: D000590:Amino Acid Chloromethyl Ketones; D000873:Anthracenes; D000991:Antithrombins; D002070:Butadienes; D052246:Cyclooxygenase 2 Inhibitors; D004791:Enzyme Inhibitors; D005419:Flavonoids; D006023:Glycoproteins; D006629:Hirudins; D008079:Lipoproteins, VLDL; D016328:NF-kappa B; D009570:Nitriles; D009578:Nitrobenzenes; D012717:Sesquiterpenes; D013449:Sulfonamides; C113580:U 0126; C021240:tissue-factor-pathway inhibitor 2; C080955:N-(2-cyclohexyloxy-4-nitrophenyl)methanesulfonamide; C432165:pyrazolanthrone; C002669:parthenolide; D048031:JNK Mitogen-Activated Protein Kinases; D020928:Mitogen-Activated Protein Kinases; D013917:Thrombin; C040308:phenylalanyl-prolyl-arginine-chloromethyl ketone; C093973:2-(2-amino-3-methoxyphenyl)-4H-1-benzopyran-4-one