Thrombin up-regulates tissue factor pathway inhibitor-2 synthesis through a cyclooxygenase-2-dependent, epidermal growth factor receptor-independent mechanism.
The serine proteinase inhibitor tissue factor pathway inhibitor-2 (TFPI-2) inhibits the tissue factor-factor VIIa complex and thereby impairs factor Xa and subsequently thrombin generation. Here we show that thrombin itself up-regulates TFPI-2 mRNA and protein expression in human liver myofibroblasts, a cell type shown to express high levels of TFPI-2 (Neaud, V., Hisaka, T., Monvoisin, A., Bedin, C., Balabaud, C., Foster, D. C., Desmoulière, A., Kisiel, W., and Rosenbaum, J. (2000) J. Biol. Chem. 275, 35565-35569). This effect required thrombin catalytic activity, as shown by its abolition with hirudin. Although the thrombin effect could be mimicked by agonists of both protease-activated receptor (PAR)-1 and PAR-4, it was largely blocked by a PAR-1 blocking antibody. Transactivation of the epidermal growth factor (EGF) receptor has been reported as a common event in thrombin signaling. However, thrombin did not detectably transactivate the EGF receptor in liver myofibroblasts, and blocking the EGF receptor did not affect TFPI-2 induction. On the other hand, thrombin increased the expression of cyclooxygenase-2 (COX-2) mRNA via a MAPK-dependent pathway, and a specific COX-2 inhibitor abolished the effect of thrombin on TFPI-2 expression. Thus, thrombin, through PAR-1 signaling, up-regulates the synthesis of TFPI-2 via a MAPK/COX-2-dependent pathway. The up-regulation of TFPI-2 expression by thrombin could in turn down-regulate thrombin generation and contribute to limit blood coagulation.
Neaud
Véronique
V
Groupe de Recherches pour l'Etude du Foie, INSERM E362 and IFR66, Université Victor Segalen Bordeaux 2, 33076 Bordeaux, France.
Duplantier
Jennifer Gillibert
JG
Mazzocco
Claire
C
Kisiel
Walter
W
Rosenbaum
Jean
J
D015152:Blotting, Northern; D015153:Blotting, Western; D002384:Catalysis; D002478:Cells, Cultured; D051546:Cyclooxygenase 2; D018076:DNA, Complementary / Q000378:metabolism; D015536:Down-Regulation; D004791:Enzyme Inhibitors / Q000494:pharmacology; D066246:ErbB Receptors / Q000378:metabolism*; D006023:Glycoproteins / Q000096:biosynthesis*; D006629:Hirudins / Q000378:metabolism; D006801:Humans; D007527:Isoenzymes / Q000378:metabolism*; D008099:Liver / Q000378:metabolism; D020935:MAP Kinase Signaling System; D008565:Membrane Proteins; D010766:Phosphorylation; D011451:Prostaglandin-Endoperoxide Synthases / Q000378:metabolism*; D012313:RNA / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D044463:Receptor, PAR-1 / Q000378:metabolism; D018179:Receptors, Thrombin / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015398:Signal Transduction; D013917:Thrombin / Q000378:metabolism / Q000502:physiology*; D013997:Time Factors; D015533:Transcriptional Activation; D015854:Up-Regulation
D018076:DNA, Complementary; D004791:Enzyme Inhibitors; D006023:Glycoproteins; D006629:Hirudins; D007527:Isoenzymes; D008565:Membrane Proteins; D012333:RNA, Messenger; D044463:Receptor, PAR-1; D018179:Receptors, Thrombin; C021240:tissue-factor-pathway inhibitor 2; D012313:RNA; D051546:Cyclooxygenase 2; C496540:PTGS2 protein, human; D011451:Prostaglandin-Endoperoxide Synthases; D066246:ErbB Receptors; D013917:Thrombin; C112908:protease-activated receptor 4