Constitutive biosynthesis of plasminogen activator inhibitor type-1 (PAI-1) by cultured human aortic endothelial cells independent of insulin

1993 ◽  
Vol 4 (8) ◽  
pp. 713-720 ◽  
Author(s):  
Kevin J. Klassen ◽  
Thomas K. Nordt ◽  
David J. Schneider ◽  
Burton E. Sobel
Keyword(s):  
Endothelial Cells ◽  
Plasminogen Activator ◽  
Plasminogen Activator Inhibitor ◽  
Aortic Endothelial Cells ◽  
Inhibitor Type ◽  
Activator Inhibitor Type ◽  
Human Aortic Endothelial Cells ◽  
Activator Inhibitor ◽  
Pai 1

scholarly journals Hepatocyte growth factor stimulates expression of plasminogen activator inhibitor type 1 and tissue factor in HepG2 cells

Blood ◽  
1994 ◽  
Vol 84 (1) ◽  
pp. 151-157 ◽  
Author(s):  
J Wojta ◽  
T Nakamura ◽  
A Fabry ◽  
P Hufnagl ◽  
R Beckmann ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Plasminogen Activator ◽  
Plasminogen Activator Inhibitor ◽  
Cell Type ◽  
Inhibitor Type ◽  
Activator Inhibitor Type ◽  
Hepatocyte Growth ◽  
Activator Inhibitor ◽  
Pai 1

Abstract HGF is a powerful mitogen for both rat and human hepatocytes, epithelial cells and endothelial cells in vitro, and is angiogenic in vivo. It has considerable homology with plasminogen and has been shown to upregulate urokinase-type plasminogen activator (u-PA) in endothelial cells as well as u-PA and its receptor in kidney epithelial cells. In this study, we report that human recombinant HGF stimulates expression of plasminogen activator inhibitor type 1 (PAI-1) and tissue factor (TF) in the human hepatoma cell line HepG2. PAI-1 antigen as determined by a specific enzyme-linked immunosorbent assay increased up to threefold in conditioned media of HepG2. This increase was dose dependent with maximum stimulation achieved with a concentration of 50 ng/mL of hepatocyte growth factor (HGF). PAI-1 antigen also increased up to fourfold in the extracellular matrix in HGF treated HepG2. The production of the PAI-1 binding protein vitronectin (Vn) was not affected by HGF. In contrast, TF activity in HepG2 treated with HGF increased up to twofold. As determined by Northern blotting, PAI-1 and TF-specific mRNA were increased significantly in the presence of HGF, whereas Vn mRNA was not affected. The increase in PAI-1 and TF mRNA was also seen when HepG2 were incubated with HGF in the presence of cycloheximide, thereby indicating that de novo protein synthesis is not required to mediate the effect. u-PA could be detected neither in unstimulated or HGF-stimulated HepG2 cells on the antigen level nor on the mRNA level. In conclusion, our data give evidence that HGF, in addition to its proliferative effect for different cell types, is also involved in the local regulation of fibrinolysis and coagulation. One could speculate that HGF might modulate processes requiring matrix degradation by increasing the expression of the protease u-PA in one cell type and by upregulating the expression of the serine protease inhibitor PAI-1 in a different cell type. Because u-PA has been shown to activate latent HGF to the active form, it could furthermore be speculated that by upregulating PAI-1, which in turn could inhibit u- PA, HGF might regulate its own activation.

scholarly journals Human fibroblasts downregulate plasminogen activator inhibitor type-1 in cultured human macrovascular and microvascular endothelial cells

Blood ◽  
1996 ◽  
Vol 88 (10) ◽  
pp. 3880-3886 ◽  
Author(s):  
JC Zhang ◽  
A Fabry ◽  
L Paucz ◽  
J Wojta ◽  
BR Binder
Keyword(s):  
Endothelial Cells ◽  
Smooth Muscle ◽  
Smooth Muscle Cells ◽  
Plasminogen Activator ◽  
Plasminogen Activator Inhibitor ◽  
Inhibitor Type ◽  
Activator Inhibitor Type ◽  
Activator Inhibitor ◽  
Pai 1

We have previously reported that plasminogen activator inhibitor type-1 (PAI-1) expression in endothelial cells (ECs) can be modulated differently by smooth muscle cells depending on their origin. Human pulmonary artery smooth muscle cells (HPASMCs) strongly downregulated PAI-1 expression in ECs. Fibroblasts (FBs) are another cell type that could come in close contact with ECs. Therefore, it was the aim of this study to investigate whether FBs could also influence the fibrinolytic potential of ECs. As in the case of HPASMCs, PAI-1 antigen produced by human umbilical vein ECs (HUVECs) cocultured with human skin FBs (HSFBs) was significantly lower as compared with the sum of PAI-1 secreted by the respective cell types cultured separately. Not only HUVECs but also human skin microvascular ECs (HSMECs) responded in a dose-dependent way to serum-free conditioned media (CM) from HSFBs from one individual donor. Similar results were obtained when CM from HSFBs from four other individual donors were used. PAI-1 mRNA decreased in HUVECs incubated for 6 hours with HSFB-CM to 24% to 55% of control, depending on the preparation of HSFBs used. A significant PAI-1 downregulatory effect was only observed when CM from low-passage HSFBs (up to passage no. 5) was used, whereas no reduction in EC PAI-1 production was observed with CM obtained from HSFBs in passage no. 8. This PAI-1 downregulatory activity present in HSFB-CM was heat-labile and had a molecular mass of approximately 5 kD. When CM from HPASMCs was analyzed in the same way, an almost identical elution profile was found. In conclusion, our data showed that FBs can decrease the expression of PAI-1 in ECs. Such an effect could be operative during wound-healing and at other capillary sites where FBs could render ECs profibrinolytic, thereby facilitating processes requiring an increase in proteolytic activity such as EC migration and proliferation.

scholarly journals Hepatocyte growth factor stimulates expression of plasminogen activator inhibitor type 1 and tissue factor in HepG2 cells

Blood ◽  
1994 ◽  
Vol 84 (1) ◽  
pp. 151-157 ◽  
Author(s):  
J Wojta ◽  
T Nakamura ◽  
A Fabry ◽  
P Hufnagl ◽  
R Beckmann ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Plasminogen Activator ◽  
Plasminogen Activator Inhibitor ◽  
Cell Type ◽  
Inhibitor Type ◽  
Activator Inhibitor Type ◽  
Hepatocyte Growth ◽  
Activator Inhibitor ◽  
Pai 1

HGF is a powerful mitogen for both rat and human hepatocytes, epithelial cells and endothelial cells in vitro, and is angiogenic in vivo. It has considerable homology with plasminogen and has been shown to upregulate urokinase-type plasminogen activator (u-PA) in endothelial cells as well as u-PA and its receptor in kidney epithelial cells. In this study, we report that human recombinant HGF stimulates expression of plasminogen activator inhibitor type 1 (PAI-1) and tissue factor (TF) in the human hepatoma cell line HepG2. PAI-1 antigen as determined by a specific enzyme-linked immunosorbent assay increased up to threefold in conditioned media of HepG2. This increase was dose dependent with maximum stimulation achieved with a concentration of 50 ng/mL of hepatocyte growth factor (HGF). PAI-1 antigen also increased up to fourfold in the extracellular matrix in HGF treated HepG2. The production of the PAI-1 binding protein vitronectin (Vn) was not affected by HGF. In contrast, TF activity in HepG2 treated with HGF increased up to twofold. As determined by Northern blotting, PAI-1 and TF-specific mRNA were increased significantly in the presence of HGF, whereas Vn mRNA was not affected. The increase in PAI-1 and TF mRNA was also seen when HepG2 were incubated with HGF in the presence of cycloheximide, thereby indicating that de novo protein synthesis is not required to mediate the effect. u-PA could be detected neither in unstimulated or HGF-stimulated HepG2 cells on the antigen level nor on the mRNA level. In conclusion, our data give evidence that HGF, in addition to its proliferative effect for different cell types, is also involved in the local regulation of fibrinolysis and coagulation. One could speculate that HGF might modulate processes requiring matrix degradation by increasing the expression of the protease u-PA in one cell type and by upregulating the expression of the serine protease inhibitor PAI-1 in a different cell type. Because u-PA has been shown to activate latent HGF to the active form, it could furthermore be speculated that by upregulating PAI-1, which in turn could inhibit u- PA, HGF might regulate its own activation.

Induction of Synthesis of Plasminogen Activator Inhibitor Type-1 byTissue-Type Plasminogen Activator in Human Hepatic and Endothelial Cells

1990 ◽  
Vol 64 (03) ◽  
pp. 412-419 ◽  
Author(s):  
Satoshi Fujii ◽  
Charles L Lucore ◽  
William E Hopkins ◽  
Joseph J Billadello ◽  
Burton E Sobel
Keyword(s):  
Endothelial Cells ◽  
Plasminogen Activator ◽  
Plasminogen Activator Inhibitor ◽  
Hep G2 ◽  
Inhibitor Type ◽  
Activator Inhibitor Type ◽  
Activator Inhibitor ◽  
Pai 1

SummaryPlasminogen activator inhibitor type-1 (PAI-1) can modify fibrinolytic activity in vitro and in vivo. The present study was performed to determine whether pharmacologic concentrations of tissue-typeplasminogen activator (t-PA) can initiate negative feedback by stimulating PAI-1 synthesis. In both human hepatoma cells (Hep G2) and human umbilical vein endothelial cells (HUVEC), t-PA increased the total concentrations and appearance of newly synthesized protein inconditioned media of free PAI-1 and PAI-1 complexed with t-PA in a dose and time dependent fashion judging from results after immunoprecipi-tation of metabolically labeled PAI-1. The t-PA effect was not attributable simply to release of stored or matrix-bound PAI-1. In HUVEC, Northern blot analyses indicated that t-PA increased steady-state levels of PAI-1 mRNA two-fold. In contrast PAI-1 mRNA expression was not increased in Hep G2 cells. Thus, mechanisms of stimulation appeared to differ in the two cell lines. The results obtained are consistent with the hypothesis that increased PAI-1 synthesis and secretion in response to t-PA may limit or attenuate fibrinolysis locally or systemically in vivo.

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