Thrombin Stimulates Expression of Tissue-Type Plasminogen Activator and Plasminogen Activator lnhibitor Type 1 in Cultured Human Vascular Smooth Muscle Cells

1993 ◽  
Vol 70 (03) ◽  
pp. 469-474 ◽  
Author(s):  
Johann Wojta ◽  
Marisa Gallicchio ◽  
Hans Zoellner ◽  
Peter Hufnagl ◽  
Karena Last ◽  
...  
Keyword(s):  
Smooth Muscle ◽  
Smooth Muscle Cells ◽  
Plasminogen Activator ◽  
Vascular Smooth Muscle Cells ◽  
Fold Increase ◽  
Tissue Type ◽  
Tissue Type Plasminogen Activator ◽  
Type Plasminogen Activator ◽  
Pai 1

SummaryThe effect of thrombin on the fibrinolytic potential of human vascular smooth muscle cells (SMC) in culture was studied. SMC of different origin responded to thrombin treatment with a dose and time dependent increase in tissue-type plasminogen activator (t-PA) and plasminogen activator inhibitor type-1 (PAI-1) levels in both cell lysates and conditioned media with maximum effects achieved at 10-20 IU/ml thrombin. PAI-1 antigen levels also increased in the extracellular matrix of thrombin treated SMC. PAI-2 levels in cell lysates of such SMC were not affected by thrombin. The effect was restricted to active thrombin, since DFP-thrombin and thrombin treated with hirudin showed no increasing effect on t-PA and PAI-1 levels in SMC.Enzymatically active thrombin also caused a four-fold increase in specific PAI-1 mRNA and a three-fold increase in t-PA mRNA.Furthermore we demonstrated the presence of high and low affinity binding sites for thrombin on the surface of SMC with a K D = 4.3 × 10−10 M and 9.0 × 104 sites per cell and a KD = 0.6 × 10−8 M and 5.8 × 105 sites per cell respectively.Thrombin could come in contact with SMC in case of vascular injury or following gap formation between endothelial cells. Our data support the idea that besides its known proliferative effect for SMC, thrombin could also modulate their fibrinolytic system.

scholarly journals Vascular Smooth Muscle Cells Potentiate Plasmin Generation by Both Urokinase and Tissue Plasminogen Activator-Dependent Mechanisms: Evidence for a Specific Tissue-Type Plasminogen Activator Receptor on These Cells

Blood ◽  
1997 ◽  
Vol 90 (6) ◽  
pp. 2312-2322 ◽  
Author(s):  
Vincent Ellis ◽  
Simon A. Whawell
Keyword(s):  
Smooth Muscle ◽  
Vascular Smooth Muscle ◽  
Smooth Muscle Cells ◽  
Plasminogen Activator ◽  
Vascular Smooth Muscle Cells ◽  
Muscle Cells ◽  
Tissue Type ◽  
Affinity Binding ◽  
Tissue Type Plasminogen Activator ◽  
Type Plasminogen Activator

Plasminogen activators play a role in the response of the vessel wall to injury, presumably by mediating the degradation of extracellular matrix (ECM) by vascular smooth muscle cells (VSMCs) that is necessary for their migration and proliferation. We have therefore investigated the ability of VSMCs to assemble specific cell surface plasminogen-activating systems. Urokinase-type plasminogen activator (uPA) bound to a single class of site on VSMCs (kd, 2 nmol/L), binding of pro-uPA resulted in a large potentiation of plasmin generation and both were competed by antibodies to the uPA receptor (uPAR). Tissue-type plasminogen activator (tPA) also bound to VSMCs as determined by functional assay, with the binding isotherms showing two classes of binding site with apparent kds of 25 and 300 nmol/L. tPA binding to the higher affinity site caused a greater than 90-fold enhancement of the activation of cell bound plasminogen, whereas the lower affinity binding, mediated primarily by the ECM, had little effect on tPA activity. The high-affinity binding of tPA to VSMCs resulted in an eightfold greater potential for plasmin generation than the binding of uPA, with this difference increasing to 15-fold after thrombin stimulation of the cells due to a 1.8-fold increase in tPA binding. These data show a novel specific tPA receptor on VSMCs that may be important for the regulation of plasminogen activation in various vascular pathologies.

scholarly journals Vascular Smooth Muscle Cells Potentiate Plasmin Generation by Both Urokinase and Tissue Plasminogen Activator-Dependent Mechanisms: Evidence for a Specific Tissue-Type Plasminogen Activator Receptor on These Cells

Blood ◽  
1997 ◽  
Vol 90 (6) ◽  
pp. 2312-2322 ◽  
Author(s):  
Vincent Ellis ◽  
Simon A. Whawell
Keyword(s):  
Smooth Muscle ◽  
Vascular Smooth Muscle ◽  
Smooth Muscle Cells ◽  
Plasminogen Activator ◽  
Vascular Smooth Muscle Cells ◽  
Muscle Cells ◽  
Tissue Type ◽  
Affinity Binding ◽  
Tissue Type Plasminogen Activator ◽  
Type Plasminogen Activator

Abstract Plasminogen activators play a role in the response of the vessel wall to injury, presumably by mediating the degradation of extracellular matrix (ECM) by vascular smooth muscle cells (VSMCs) that is necessary for their migration and proliferation. We have therefore investigated the ability of VSMCs to assemble specific cell surface plasminogen-activating systems. Urokinase-type plasminogen activator (uPA) bound to a single class of site on VSMCs (kd, 2 nmol/L), binding of pro-uPA resulted in a large potentiation of plasmin generation and both were competed by antibodies to the uPA receptor (uPAR). Tissue-type plasminogen activator (tPA) also bound to VSMCs as determined by functional assay, with the binding isotherms showing two classes of binding site with apparent kds of 25 and 300 nmol/L. tPA binding to the higher affinity site caused a greater than 90-fold enhancement of the activation of cell bound plasminogen, whereas the lower affinity binding, mediated primarily by the ECM, had little effect on tPA activity. The high-affinity binding of tPA to VSMCs resulted in an eightfold greater potential for plasmin generation than the binding of uPA, with this difference increasing to 15-fold after thrombin stimulation of the cells due to a 1.8-fold increase in tPA binding. These data show a novel specific tPA receptor on VSMCs that may be important for the regulation of plasminogen activation in various vascular pathologies.

LRP and αvβ3 mediate tPA activation of smooth muscle cells

2006 ◽  
Vol 291 (3) ◽  
pp. H1351-H1359 ◽  
Author(s):  
Sa'ed Akkawi ◽  
Taher Nassar ◽  
Mark Tarshis ◽  
Douglas B. Cines ◽  
Abd Al-Roof Higazi
Keyword(s):  
Smooth Muscle ◽  
Vascular Smooth Muscle ◽  
Smooth Muscle Cells ◽  
Plasminogen Activator ◽  
Vascular Smooth Muscle Cells ◽  
Density Lipoprotein ◽  
Plasminogen Activator Inhibitor ◽  
Muscle Cells ◽  
Tissue Type ◽  
Pai 1

Tissue-type plasminogen activator (tPA) regulates vascular contractility through the low-density lipoprotein-related receptor (LRP), and this effect is inhibited by plasminogen activator inhibitor type 1 (PAI-1). We now report that tPA-mediated vasocontraction also requires the integrin αvβ3. tPA-induced contraction of rat aortic rings is inhibited by the Arg-Gly-Asp (RGD) peptide and by monoclonal anti-αvβ3 antibody. tPA induces the formation of a complex between LRP and αvβ3 in vascular smooth muscle cells. The three proteins are internalized within 10 min, causing the cells to become refractory to the readdition of tPA. LRP and αvβ3 return to the cell surface by 90 min, restoring cell responsiveness to tPA. PAI-1 and the PAI-1-derived hexapeptide EEIIMD abolish the vasocontractile activity of tPA and inhibit the tPA-mediated interaction between LRP and αvβ3. tPA induces calcium mobilization from intracellular stores in vascular smooth muscle cells, and this effect is inhibited by PAI-1, RGD, and antibodies to both LRP and αvβ3. These data indicate that tPA-mediated vasocontraction involves the coordinated interaction of LRP with αvβ3. Delineating the mechanism underlying these interactions and the nature of the signals transduced may provide new tools to regulate vascular tone and other consequences of tPA-mediated signaling.

scholarly journals Prognostic value of tissue-type plasminogen activator (tPA) and its complex with the type-1 inhibitor (PAI-1) in breast cancer

1999 ◽  
Vol 80 (1-2) ◽  
pp. 286-294 ◽  
Author(s):  
J H de Witte ◽  
C G J Sweep ◽  
J G M Klijn ◽  
N Grebenschikov ◽  
H A Peters ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Plasminogen Activator ◽  
Prognostic Value ◽  
Tissue Type ◽  
Tissue Type Plasminogen Activator ◽  
Type Plasminogen Activator ◽  
Pai 1

scholarly journals The majority of type 1 plasminogen activator inhibitor associated with cultured human endothelial cells is located under the cells and is accessible to solution-phase tissue-type plasminogen activator.

1990 ◽  
Vol 110 (1) ◽  
pp. 155-163 ◽  
Author(s):  
R R Schleef ◽  
T J Podor ◽  
E Dunne ◽  
J Mimuro ◽  
D J Loskutoff
Keyword(s):  
Endothelial Cells ◽  
Plasminogen Activator ◽  
Plasminogen Activator Inhibitor ◽  
Solution Phase ◽  
Tissue Type ◽  
Tissue Type Plasminogen Activator ◽  
Type Plasminogen Activator ◽  
Activator Inhibitor ◽  
Pai 1

The interactions between exogenously added tissue-type plasminogen activator (t-PA) and the active form of type 1 plasminogen activator inhibitor (PAI-1) produced by and present in cultured human umbilical vein endothelial cells (HUVECs) were investigated. Immunoblotting analysis of the conditioned media obtained from monolayers of HUVECs treated with increasing concentrations of t-PA (less than or equal to 10 micrograms/ml) revealed a dose-dependent formation of both t-PA/PAI-1 complexes, and of a 42,000-Mr cleaved or modified form of the inhibitor. Immunoradiometric assays indicated that t-PA treatment resulted in a fourfold increase in PAI-1 antigen present in the conditioned media. This increase did not result from the release of PAI-1 from intracellular stores, but rather reflected a t-PA-dependent decrease in the PAI-1 content of the Triton X-100 insoluble extracellular matrix (ECM). Although the rate of t-PA-mediated release of PAI-1 was increased by the removal of the monolayer, similar quantities of PAI-1 were removed in the presence or absence of the cells. These results suggest that the cells only represent a semipermeable barrier between ECM-associated PAI-1 and exogenous t-PA. Treatment of HUVECs with t-PA (1 microgram/ml, 2 h) to deplete the ECM of PAI-1 did not affect the subsequent rate of PAI-1 production and deposition into the ECM. Immunogold electron microscopy of HUVECs not only confirmed the location of PAI-1 primarily in the region between the culture substratum and ventral cell surface but failed to demonstrate significant (less than 1%) PAI-1 on the cell surface. Thus, the majority of PAI-1 associated with cultured HUVEC monolayers is present under the cells in the ECM and is accessible to solution-phase t-PA.

Production of Tissue-Type Plasminogen Activator (t-PA) and Type-1 Plasminogen Activator Inhibitor (PAI-1) in Mildly Cirrhotic Rat Liver

1996 ◽  
Vol 75 (05) ◽  
pp. 801-807 ◽  
Author(s):  
Taiichiro Seki ◽  
Hideo Imai ◽  
Shigeyuki Uno ◽  
Toyohiko Ariga ◽  
Thomas D Gelehrter
Keyword(s):  
Plasminogen Activator ◽  
Rat Liver ◽  
Plasminogen Activator Inhibitor ◽  
Tissue Type ◽  
Tissue Type Plasminogen Activator ◽  
Type Plasminogen Activator ◽  
Activator Inhibitor ◽  
Pai 1

SummaryWe have studied the production of tissue-type plasminogen activator (t-PA) and type-1 plasminogen activator inhibitor (PAI-1) in liver of normal rats and in rats with mild cirrhosis induced by carbon tetrachloride inhalation, to demonstrate the production of these fibrinolytic components and their pathophysiologic role in the liver in vivo. Immunohistochemical study of paraffin-embedded liver sections and fibrin autography of frozen sections showed that the normal rat liver produces very little t-PA or PAI-1. On the contrary, striking t-PA activity and both t-PA and PAI-1 antigens were observed in the cirrhotic liver. Both t-PA and PAI-1 in plasma were also markedly increased in the cirrhotic rats. Because the hepatocyte can internalize t-PA or PA/PAI-1 complexes from circulation, Northern blot analysis of the total liver RNA was performed to demonstrate the endogenous synthesis of t-PA and PAI-1 in the liver. Although the normal liver hardly expresses either t-PA or PAI-1 mRNA, striking t-PA and PAI-1 mRNA expression was observed in the liver of rats with mild cirrhosis.These data demonstrate that t-PA and PAI-1 production is strongly upregulated in the liver in rats with mild cirrhosis. These fibrinolytic components, whose production is closely associated with liver failure, may play important roles in the regulation of hepatocyte proliferation and liver regeneration in vivo.

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