Evidence for the Occurrence of a Fast-Acting Inhibitor for Tissue-Type Plasminogen Activator in Human Plasma

Verheijen, J.H.; Chang, Glenn T.G.; Kluft, C.

doi:10.1055/s-0038-1661109

Cited by 377 publications

(160 citation statements)

References 10 publications

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“…The properties ofthe thrombin-induced endothelial cell PA-I are the same as those previously described by us for the PA-I induced by glucocorticoids in rat hepatoma cells (10)(11)(12)(13) and by others for the PA-I in human plasma (23)(24)(25)(26), platelets (7), and cultured human (2-4) and bovine endothelial cells (5,27). As shown in Fig.…”

Section: Resultssupporting

confidence: 62%

Thrombin induction of plasminogen activator-inhibitor in cultured human endothelial cells.

1986

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We have examined the effect of thrombin on the activity of plasminogen activator (PA) and plasminogen activator-inhibitor (PA-I) in medium conditioned by primary cultures of human umbilical vein endothelial cells. PA activity was measured by fibrinolytic and esterolytic assays, and total tissue-type PA (tPA) antigen by radioimmunoassay. Net PA-I activity was assayed by titration of human urokinase esterolytic activity. Incubation of confluent endothelial cell cultures with thrombin for 24 h caused a sixfold increase in PA-I activity. The effect of thrombin was half-maximal at -0.4 U/ml (<4 nM), and required concomitant RNA and protein synthesis. The stimulation of PA-I activity required active a-thrombin and was not obtained with 'y-thrombin nor with thrombin catalytically inactivated with hirudin. Because of the excess of PA-I, PA activity was not measurable in either control or thrombin-treated cells. Thrombin did, however, increase medium concentration of tPA antigen by approximately fourfold. The thrombin-induced PA-I inhibited both tPA and urokinase, did not lose activity upon acidification, and was stable to sodium dodecyl sulfate and thiol reduction. We conclude that physiologic concentrations of thrombin increase both PA-I activity and tPA antigen in medium conditioned by human umbilical vein endothelial cells. Because there was always a several-fold increase in the net activity of free PA-I, these observations suggest that the net effect of thrombin is to decrease fibrinolytic activity in human endothelial cells. Thus, thrombin, in addition to its role in coagulation, may protect clots from premature lysis by increasing the amount of a specific fibrinolytic inhibitor.

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Section: Resultssupporting

confidence: 62%

Thrombin induction of plasminogen activator-inhibitor in cultured human endothelial cells.

1986

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“…Specific protein inhibitors of PA have also been identified in a number of tissues, body fluids, and cell cultures (10,14,18,19,22,26,30,35,42,44,56,66,70,73,78,80,81,83), though the mutual relationship of these inhibitors is not yet fully clarified. An Mr 54,000 plasminogen activator inhibitor (PAI) was recently purified from the human fibrosarcoma cell line HT-1080 (4), and immunologic evidence sug- : HES, human embryonic skin; PA, plasminogen activator; PAl, PAl-l, or PAl-2, plasminogen activator inhibitor, or specifically, PAl type 1 or type 2; t-PA, tissue-type plasminogen activator; u-PA, urokinase-type plasminogen activator; TNP, trinitrophenyl. gested that it is of the same type as the inhibitors from the rat hepatoma cell line HTC (66), bovine endothelial cells (18,42,44,56,70), and human blood platelets (19).…”

mentioning

confidence: 99%

Distinct localizations of urokinase-type plasminogen activator and its type 1 inhibitor under cultured human fibroblasts and sarcoma cells

Pöllänen¹,

Saksela²,

Salonen³

et al. 1987

The Journal of Cell Biology

296

127

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Abstract. We studied the immunocytochemical localization of urokinase-type plasminogen activator (u-PA) and the type 1 plasminogen activator inhibitor (PAI-1) in human fibroblasts and sarcoma cells, using both polyclonal and monoclonal antibodies. The u-PA was found to be located at discrete cell-substratum contact sites, and also at areas of cell-cell contacts, whereas PAI-1 was distributed as a homogenous carpet excluding strialike areas on the substrate under the cells. To confirm the extracellular localization of u-PA and PAIl, we stained the cells live at 0°C before fixation. A double-labeling experiment showed different distribution of u-PA and PAI-1 under the cells, and especially their peripheral parts. The staining pattern of u-PA and PAI-1 resisted treatment with 0.2% saponin followed by mechanical removal of cells, a method previously reported to isolate focal contact membranes of fibroblasts. We further demonstrated the deposition of u-PA to the contact areas of cells obtained by saponin treatment by zymography, and that of PAI-1 by metabolic labeling, reverse zymography, immunoblotting, and immunoprecipitation. Fibronectin was also present in the preparations. The deposition of both PAI-1 and fibronectin by the sarcoma cells was enhanced, after treating the cells with 10 -6 M dexamethasone. The confinement of u-PA to discrete contact sites and the more uniform distribution of PAI-1 on the cell substratum may explain how cells producing large amounts of enzyme inhibitors can produce PAmediated focal proteolysis.

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“…Sodium citrate was used as anti-coagulant to collect the blood plasma and PA, PAI [6], glucose and fibrinogen [7] estimations were carried out. Total cholesterol [8], triglycerides [9], HDL cholesterol [10] were estimated in serum.…”

Section: Methodsmentioning

confidence: 99%

Effect of Growth Hormone on Plasminogen Activator and Inhibitor Activity in Rat

et al. 2012

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Growth retardation is one of the significant changes in chronic kidney disease (CKD) and is associated with increased morbidity and mortality. Disturbances in growth hormone (GH) are held responsible for several complications in CKD. GH is a protein based peptide hormone which directly or indirectly regulates renal functions to ensure homeostasis. We investigated the effects of growth hormone on plasminogen activators (PA) in rat kidney, PA and plasminogen activator inhibitor (PAI), glucose and fibrinogen in plasma and serum lipid profile. Rats were injected daily with 250 mU GH kg-1 body weight subcutaneously for one week. Growth hormone treatment increased PA activity significantly in rat kidneys as compared to controls. No changes were seen in PA, PAI and fibrinogen levels in the plasma of two groups of rats. There was significant decrease in plasma glucose, total cholesterol and LDL-cholesterol levels in serum of treated group resulting in the decrease of HDL/LDL and total cholesterol/cholesterol ratios. However, triglycerides and VLDL showed significant higher activity in the serum of treated group as compared to controls. Our data suggests that GH administration might improve renal function by increasing PA activity in kidney as well as by reducing the cholesterol content in blood. GH may be effective in improving growth failure as it helps to maintain the normal homeostatic balance.

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Evidence for the Occurrence of a Fast-Acting Inhibitor for Tissue-Type Plasminogen Activator in Human Plasma

Cited by 377 publications

References 10 publications

Thrombin induction of plasminogen activator-inhibitor in cultured human endothelial cells.

Thrombin induction of plasminogen activator-inhibitor in cultured human endothelial cells.

Distinct localizations of urokinase-type plasminogen activator and its type 1 inhibitor under cultured human fibroblasts and sarcoma cells

Effect of Growth Hormone on Plasminogen Activator and Inhibitor Activity in Rat

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