Regulation of endothelial tissue plasminogen activator and plasminogen activator inhibitor type 1 synthesis by diacylglycerol, phorbol ester, and thrombin.
The influence of diacylglycerols, which are physiological activators of protein kinase C, on the production of tissue-type plasminogen activator (tPA) and plasminogen activator inhibitor type 1 (PAI-1) by human umbilical vein endothelial cells (HUVEC) was studied in order to gain insight into the regulation of fibrinolysis by these cells. 1,2-dioctanoyl-sn-glycerol (diC8) stimulated tPA production in a dose- and time-dependent manner. The tPA antigen in cell supernatants increased from 0.9 ng/10(6) cells in unstimulated cells to 12.4 ng (10(6) cells after incubation with 400 microM diC8 for 24 hours. In contrast, PAI-1 production was not influenced by diC8, whereas phorbol 12-myristate 13-acetate (PMA) or thrombin stimulated both, tPA and PAI-1 production by HUVEC. Staurosporine and H7, which are inhibitors of protein kinase C, inhibited tPA synthesis by HUVEC. The degree of inhibition was dependent on the agonist used. While diC8-induced tPA production was inhibited to more than 80% by H7 (10 microM) and staurosporine (10 nM), higher doses of inhibitors were required to inhibit thrombin- and PMA-induced tPA production. Thrombin-induced PAI-1 production was inhibited to more than 80% by H7 (10 microM) and to about 50% by staurosporine, whereas PMA-induced PAI-1 production was not inhibited by staurosporine, and only to about 50% by higher doses of H7 (30 microM). These data suggest that activation of protein kinase C is a common intracellular trigger mechanism for the induction of tPA synthesis by HUVEC. Protein kinase C is most likely also involved in the regulation of PAI-1 synthesis by HUVEC.
Grulich-Henn
J
J
Clinical Research Unit for Blood Coagulation and Thrombosis, Max-Planck-Gesellschaft, Giessen, Federal Republic of Germany.
Müller-Berghaus
G
G
D004075:Diglycerides / Q000494:pharmacology; D004730:Endothelium, Vascular / Q000378:metabolism*; D005786:Gene Expression Regulation / Q000187:drug effects; D006801:Humans; D066298:In Vitro Techniques; D015849:Plasminogen Inactivators / Q000378:metabolism*; D011493:Protein Kinase C / Q000037:antagonists & inhibitors / Q000502:physiology*; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D013917:Thrombin / Q000494:pharmacology; D010959:Tissue Plasminogen Activator / Q000096:biosynthesis*
D004075:Diglycerides; D015849:Plasminogen Inactivators; D011493:Protein Kinase C; D013917:Thrombin; D010959:Tissue Plasminogen Activator; D013755:Tetradecanoylphorbol Acetate