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Submitted on September 25, 2001
Accepted on February 17, 2002
From the Department of Cardiovascular Medicine (T.K., S.F., D.G., N.I., K.W., T.F., T.S., A.K.), Hokkaido University Graduate School of Medicine, Sapporo, Japan; the Howard Hughes Medical Institute (A.M.), Duke University, Durham, NC; and the Department of Medicine (B.E.S.), University of Vermont, Burlington.
* To whom correspondence should be addressed. E-mail: sfujii{at}med.hokudai.ac.jp.
AbstractPlasminogen
activator inhibitor-1 (PAI-1) inhibits
fibrinolysis and proteolysis. Basic fibroblast growth
factor (bFGF) stimulates angiogenesis, which requires regional
proteolysis. Because modulation of vasculopathy requires tight control
of proteolysis, effects of bFGF on PAI-1 expression in
endothelial cells (ECs) were characterized. bFGF
increased PAI-1 mRNA and accumulation of PAI-1 protein in conditioned
media in human umbilical vein ECs. The bFGF-mediated increase in PAI-1
mRNA was attenuated by inhibition of extracellular signal--regulated
kinase kinase in human ECV304 cells. The rate of decrease in PAI-1 mRNA
after actinomycin D treatment was not affected by bFGF. Transient
transfection assays of the human PAI-1 promoter-luciferase construct
demonstrated that bFGF-induced PAI-1 transcription was dependent on the
elements within the -313 to -260 bp relative to the transcription
start site. This region contains an Ets-1--like site.
Electrophoretic mobility shift assay showed that bFGF increased nuclear
translocation or DNA binding of the Ets-1--like transcription factor to
the PAI-1 promoter. Nucleotide substitution to disrupt the
Ets-1--like site reduced bFGF-stimulated promoter activity. Fenofibric
acid, an agonist ligand for the peroxisome
proliferator--activated receptor-
, inhibited basal and
bFGF-stimulated PAI-1 expression. By inducing PAI-1 expression from
ECs, bFGF may control proteolysis and fibrinolysis in
vessel walls.
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