Heparin-binding growth factor-1 modulation of plasminogen activator inhibitor-1 expression. Interaction with cAMP and protein kinase C-mediated pathways.
Plasminogen activator inhibitor-1 (PAI-1) inhibits the tissue plasminogen activator (tPA) and urokinase activation of plasminogen to plasmin, a protease of trypsin-like specificity which is involved in a number of processes, including fibrinolysis, matrix degradation and angiogenesis. Both phorbol esters and cAMP elevating compounds have been shown to modulate PAI-1 and tPA expression in endothelial cell culture. HBGF-1 (previously designated endothelial cell growth factor) stimulates endothelial cell growth in vitro and is angiogenic in vivo. We have reported that removal of HBGF-1 from human umbilical vein endothelial cell (HUVEC) media results in an approximately 5-fold increase in PAI-1 mRNA levels and in PAI-1 protein secreted into the media by 20 h. Here we report the effects of HBGF-1 on the phorbol ester and cAMP modulation of HUVEC PAI-1 expression. The phorbol ester PMA induced an approximate 5-fold increase in PAI-1 mRNA levels at 4 h, which returned to base line by 20 h, with or without HBGF-1 present in the media. This increase in PAI-1 mRNA levels was mediated by an increase in PAI-1 gene transcription and was abated in the presence of cycloheximide. Treatment of cells with the adenylate cyclase activator forskolin or the phosphodiesterase inhibitor HL 725, in the presence of HBGF-1 or immediately after its withdrawal, decreased PAI-1 mRNA levels and protein secreted into the conditioned media by 20 h. However, forskolin or HL 725 addition had little or no effect on PAI-1 mRNA when added 20 h after HBGF-1 withdrawal. Both the PMA and HBGF-1 modulation of PAI-1 were abolished by treatment with the protein kinase inhibitor H-7. Treatment of HUVEC with HBGF-1 had no acute effect on intracellular inositol phosphate hydrolysis or cAMP levels. Further studies on intracellular pathways involved in HBGF-1 modulation of PAI-1 will enhance our understanding of the role these factors play in cellular proliferation and angiogenesis.
Konkle
B A
BA
Department of Medicine, Jefferson Medical College of Thomas Jefferson University, Philadelphia, Pennsylvania 19107.
Kollros
P R
PR
Kelly
M D
MD
D019307:1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine; D015152:Blotting, Northern; D002478:Cells, Cultured; D005576:Colforsin / Q000494:pharmacology; D000242:Cyclic AMP / Q000502:physiology*; D003513:Cycloheximide / Q000494:pharmacology; D016220:Fibroblast Growth Factor 1 / Q000494:pharmacology*; D015870:Gene Expression; D006801:Humans; D066298:In Vitro Techniques; D007295:Inositol Phosphates / Q000378:metabolism; D007546:Isoquinolines / Q000494:pharmacology; D010879:Piperazines / Q000494:pharmacology; D015849:Plasminogen Inactivators / Q000378:metabolism*; D011493:Protein Kinase C / Q000037:antagonists & inhibitors / Q000502:physiology*; D015398:Signal Transduction; D010959:Tissue Plasminogen Activator / Q000235:genetics; D014158:Transcription, Genetic / Q000187:drug effects
D007295:Inositol Phosphates; D007546:Isoquinolines; D010879:Piperazines; D015849:Plasminogen Inactivators; D016220:Fibroblast Growth Factor 1; D005576:Colforsin; D019307:1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine; D003513:Cycloheximide; D000242:Cyclic AMP; D011493:Protein Kinase C; D010959:Tissue Plasminogen Activator