Identification of intracellular pathways through which TGF-beta1 upregulates PAI-1 expression in endothelial cells.
Upregulation of plasminogen activator inhibitor type 1 (PAI-1) expression is a critical mechanism through which transforming growth factor-beta1 (TGF-beta1) accelerates intimal growth. The aim of this study was to identify signaling pathways through which TGF-beta1 upregulates PAI-1 expression in endothelial cells (EC) and test interventions for blocking these pathways. We transduced cultured bovine EC with an adenoviral vector containing the PAI-1 promoter fused to a beta-galactosidase reporter gene. We used these cells, along with vectors expressing potential modifiers of TGF-beta1 signaling and pharmacologic antagonists of mitogen-activated protein kinase (MAPK) pathways to identify key mediators of basal and TGF-beta1-regulated PAI-1 expression. Basal activity of the PAI-1 promoter was directly correlated with Ras activation and was blocked by a dominant negative (DN) type I TGF-beta receptor. TGF-beta1-stimulated activity of the PAI-1 promoter did not require Ras activation, and was lessened or eliminated by expression of either DN type I or type II TGF-beta receptors and by inhibition of either of two MAPKs: MEK and p38. Our results suggest unanticipated pathways of TGF-beta1 signaling in EC and point to new strategies to limit TGF-beta1-induced vascular disease.
Woodward
Robert N
RN
Gladstone Institute of Cardiovascular Disease, University of California, San Francisco, CA 94158, USA.
Finn
Aloke V
AV
Dichek
David A
DA
D000256:Adenoviridae / Q000235:genetics; D000818:Animals; D002417:Cattle; D002478:Cells, Cultured; D004730:Endothelium, Vascular / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D018014:Gene Transfer Techniques; D005822:Genetic Vectors / Q000008:administration & dosage; D066298:In Vitro Techniques; D020929:Mitogen-Activated Protein Kinase Kinases / Q000378:metabolism; D017395:Plasminogen Activator Inhibitor 1 / Q000235:genetics*; D011651:Pulmonary Artery / Q000166:cytology / Q000378:metabolism; D015398:Signal Transduction; D016212:Transforming Growth Factor beta / Q000494:pharmacology*; D053773:Transforming Growth Factor beta1; D015854:Up-Regulation / Q000187:drug effects*
D017395:Plasminogen Activator Inhibitor 1; D016212:Transforming Growth Factor beta; D053773:Transforming Growth Factor beta1; D020929:Mitogen-Activated Protein Kinase Kinases