Hepatocyte growth factor regulates E box-dependent plasminogen activator inhibitor type 1 gene expression in HepG2 liver cells.
OBJECTIVE
We sought to determine the etiologic mechanism of pleiotropic growth factor, hepatocyte growth factor (HGF), as a regulator of hepatic synthesis of plasminogen activator inhibitor (PAI)-1, the physiological inhibitor of fibrinolysis and a potential inducer of atherothrombosis.


RESULTS
HGF increased PAI-1 mRNA expression and PAI-1 protein accumulation in the conditioned media of human liver-derived HepG2 cells, and increased hepatic PAI-1 mRNA expression in vivo in mice. HGF-inducible PAI-1 mRNA was attenuated by U0126, a specific inhibitor of mitogen-activated protein kinase (MAPK) kinase, and genistein, an inhibitor of tyrosine kinase. HGF increased the human PAI-1 promoter (-829 to +36 bp) activity, and deletion and mutation analysis uncovered a functional E box (5'-CACATG-3') at positions -158 to -153 bp. Electrophoretic mobility shift assays demonstrated that this E box binds upstream stimulatory factors (USFs). HGF phosphorylated USFs through MAPK and tyrosine kinase pathways. Co-transfection of USF1 expression vector increased PAI-1 promoter activity. Sterol regulatory element-binding protein-1 attenuated HGF-inducible PAI-1 promoter activity.


CONCLUSIONS
Because USFs are involved in the regulation of carbohydrates and lipid metabolism, HGF-mediated PAI-1 production may provide a novel link between atherothrombosis and metabolic derangements. Targeting HGF signaling pathway may modulate the thrombotic risk in high-risk patients.
Imagawa
Shogo
S
The Department of Cardiovascular Medicine, Hokkaido University Graduate School of Medicine, Kita 15, Nishi 7, Kitaku, Sapporo, Japan 060-8638.
Fujii
Satoshi
S
Dong
Jie
J
Furumoto
Tomoo
T
Kaneko
Takeaki
T
Zaman
Tarikuz
T
Satoh
Yuki
Y
Tsutsui
Hiroyuki
H
Sobel
Burton E
BE
D000818:Animals; D045744:Cell Line, Tumor; D004247:DNA; D024721:E-Box Elements; D005786:Gene Expression Regulation; D017228:Hepatocyte Growth Factor / Q000502:physiology*; D006801:Humans; D008099:Liver / Q000378:metabolism*; D020935:MAP Kinase Signaling System; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D020929:Mitogen-Activated Protein Kinase Kinases / Q000378:metabolism; D010766:Phosphorylation; D017395:Plasminogen Activator Inhibitor 1 / Q000235:genetics*; D011401:Promoter Regions, Genetic; D017434:Protein Structure, Tertiary; D011505:Protein-Tyrosine Kinases / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D015398:Signal Transduction / Q000502:physiology; D051779:Sterol Regulatory Element Binding Proteins / Q000502:physiology; D051720:Upstream Stimulatory Factors / Q000502:physiology
D017395:Plasminogen Activator Inhibitor 1; D012333:RNA, Messenger; D051779:Sterol Regulatory Element Binding Proteins; D051720:Upstream Stimulatory Factors; D017228:Hepatocyte Growth Factor; D004247:DNA; D011505:Protein-Tyrosine Kinases; D020929:Mitogen-Activated Protein Kinase Kinases