title: Complex intracellular signal transduction regulates tissue plasminogen activator (t-PA) and plasminogen activator inhibitor type-1 (PAI-1) synthesis in cultured human umbilical vein endothelium.
abstract: Endothelial cells are central in fibrinolysis because of their high production of both activators (t-PA, uPA) and inhibitors (PAI-1). The t-PA and PAI-1 synthesis could be regulated by signals transduction at several cellular levels. The purpose of this in vitro study, on cultured endothelial cells, was to explore the receptor/second messenger regulation of the t-PA and PAI-1 synthesis. Quiescent confluent human umbilical vein endothelial cells, cultured in passage 1, were exposed to different test substances. Samples from the conditioned medium were collected after 16 and 24 h and analysed for t-PA and PAI-1 antigen. All data presented were related to the data from control dishes (= 100%), in the same experiment. The results from the present study (mean +/- 95% confidence interval) demonstrated the following. (1) Forskolin, with a documented direct cAMP-inducing effect, decreased the basal PAI-1 production to 61 +/- 15%, and Na-nitroprusside, with a documented cGMP-inducing effect, increased the basal PAI-1 production to 141 +/- 38% without affecting the basal t-PA production. The surface receptor agonists isoprenalin or ephedrine, which indirectly affect adenylate cyclase, had no effect on t-PA or PAI-1 production. (2) Phorbolester (PMA), which directly activates proteinkinase C (PKC), increased the basal t-PA and PAI-1 production to 350 +/- 71%, and 163 +/- 35% respectively. (3) Thrombin, but not endothelin-1 (ET-1), increased the basal t-PA and PAI-1 production to 195 +/- 34% and 136 +/- 18%, respectively, indicating an PKC-mediated thrombin effect.(ABSTRACT TRUNCATED AT 250 WORDS)
authors.affiliation: Department of Surgery, Ostra Hospital, University of Göteborg, Sweden.
authors.forename: H
authors.initials: H
authors.lastname: Rydholm
authors.forename: S
authors.initials: S
authors.lastname: Boström
authors.forename: E
authors.initials: E
authors.lastname: Eriksson
authors.forename: B
authors.initials: B
authors.lastname: Risberg
mesh_terms: D002478:Cells, Cultured; D005576:Colforsin / Q000494:pharmacology; D016232:Endothelins / Q000494:pharmacology; D004730:Endothelium, Vascular / Q000378:metabolism*; D004731:Endotoxins / Q000494:pharmacology; D004809:Ephedrine / Q000494:pharmacology; D006801:Humans; D007545:Isoproterenol / Q000494:pharmacology; D009599:Nitroprusside / Q000494:pharmacology; D017395:Plasminogen Activator Inhibitor 1 / Q000096:biosynthesis*; D015398:Signal Transduction; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D013917:Thrombin / Q000494:pharmacology; D010959:Tissue Plasminogen Activator / Q000096:biosynthesis*; D014471:Umbilical Veins
chemical_list: D016232:Endothelins; D004731:Endotoxins; D017395:Plasminogen Activator Inhibitor 1; D009599:Nitroprusside; D005576:Colforsin; D013917:Thrombin; D010959:Tissue Plasminogen Activator; D004809:Ephedrine; D007545:Isoproterenol; D013755:Tetradecanoylphorbol Acetate