Plasminogen-dependent and -independent Proteolytic Activity of Murine Endothelioma Cells with Targeted Inactivation of Fibrinolytic Genes

1997 ◽  
Vol 77 (02) ◽  
pp. 362-367 ◽  
Author(s):  
H R Lijnen ◽  
E F Wagner ◽  
D Collen
Keyword(s):  
Extracellular Matrix ◽  
Plasminogen Activator ◽  
Proteolytic Activity ◽  
Tissue Type ◽  
Plasminogen Activation ◽  
Matrix Degradation ◽  
Wild Type ◽  
Type Plasminogen Activator ◽  
Targeted Inactivation ◽  
Pai 1

SummaryPlasminogen-dependent and -independent proteolytic activity of murine endothelioma (End) cells that were derived from mice with targeted inactivation of the tissue-type plasminogen activator (t-PA -/-), urokinase-type plasminogen activator (u-PA-/-) or plasminogen activator inhibitor-1 (PAI-1 -/- genes was studied with the use of fibrin and extracellular matrix degradation assays. In a buffer milieu, the activation rate of plasminogen (final concentration 0.25 µM) with wild-type and t-PA-/- End cells (3 X 104 to 4 X 106 cells/ml) was comparable, but it was about 4-fold reduced with u-PA -/- End cells and 3-fold enhanced with PAI-1End cells. Plasminogen activation was markedly reduced by addition of amiloride or of anti-murine u-PA antibodies but not by addition of anti-murine t-PA antibodies, and it was not stimulated by addition of fibrin. Lysis of125I-fibrin labeled matrix in the presence of plasminogen was comparable with wild-type, t-PA-/- and PAI-1-/- End cells (50% lysis in 3 h with 0.7 to 1.5 X 106 cells/ml), but was significantly reduced with u-PA-/- End cells (50% lysis in 20 h with 0.87 X 106 cells/ml). Lysis of3H-proline labeled extracellular matrix in the presence of plasminogen with wild-type, t-PA-/- and PAI-1-/- End cells (20% lysis in 48 h with 3 to 5 X 106 cells/ml) was comparable, but it was virtually abolished with u-PA-/- End cells. In the absence of plasminogen, lysis of both the fibrin and the extracellular matrix by all four cell types was drastically reduced and was virtually abolished by addition of phenylmethylsulfonylfluoride or 1,10 phenanthroline.These data indicate that the proteolytic activity of the transformed murine endothelioma cells, measured in plasminogen activation or matrix degradation assays, is essentially u-PA-related and largely plasminogen-dependent.

Differential Role of Components of the Fibrinolytic System in the Formation and Removal of Thrombus Induced by Endothelial Injury

1999 ◽  
Vol 81 (04) ◽  
pp. 601-604 ◽  
Author(s):  
Hiroyuki Matsuno ◽  
Osamu Kozawa ◽  
Masayuki Niwa ◽  
Shigeru Ueshima ◽  
Osamu Matsuo ◽  
...  
Keyword(s):  
Plasminogen Activator ◽  
Thrombus Formation ◽  
Endothelial Injury ◽  
Fibrinolytic System ◽  
Tissue Type ◽  
Clot Lysis ◽  
Wild Type ◽  
Type Plasminogen Activator ◽  
Pai 1

SummaryThe role of fibrinolytic system components in thrombus formation and removal in vivo was investigated in groups of six mice deficient in urokinase-type plasminogen activator (u-PA), tissue-type plasminogen activator (t-PA), or plasminogen activator inhibitor-1 (PAI-1) (u-PA-/-, t-PA-/- or PAI-1-/-, respectively) or of their wild type controls (u-PA+/+, t-PA+/+ or PAI-1+/+). Thrombus was induced in the murine carotid artery by endothelial injury using the photochemical reaction between rose bengal and green light (540 nm). Blood flow was continuously monitored for 90 min on day 0 and for 20 min on days 1, 2 and 3. The times to occlusion after the initiation of endothelial injury in u-PA+/+, t-PA+/+ or PAI-1+/+ mice were 9.4 ± 1.3, 9.8 ± 1.1 or 9.7 ± 1.6 min, respectively. u-PA-/- and t-PA-/- mice were indistinguishable from controls, whereas that of PAI-1-/- mice were significantly prolonged (18.4 ± 3.7 min). Occlusion persisted for the initial 90 min observation period in 10 of 18 wild type mice and was followed by cyclic reflow and reocclusion in the remaining 8 mice. At day 1, persistent occlusion was observed in 1 wild type mouse, 8 mice had cyclic reflow and reocclusion and 9 mice had persistent reflow. At day 2, all injured arteries had persistent reflow. Persistent occlusion for 90 min on day 0 was observed in 3 u-PA-/-, in all t-PA-/- mice at day 1 and in 2 of the t-PA-/-mice at day 2 (p <0.01 versus wild type mice). Persistent patency was observed in all PAI-1-/- mice at day 1 and in 5 of the 6 u-PA-/- mice at day 2 (both p <0.05 versus wild type mice). In conclusion, t-PA increases the rate of clot lysis after endothelial injury, PAI-1 reduces the time to occlusion and delays clot lysis, whereas u-PA has little effect on thrombus formation and spontaneous lysis.

Inhibitor-Resistant Tissue-Type Plasminogen Activator: An Improved Thrombolytic Agent In Vitro

1994 ◽  
Vol 71 (01) ◽  
pp. 124-128 ◽  
Author(s):  
R V Shohet ◽  
S Spitzer ◽  
E L Madison ◽  
R Bassel-Duby ◽  
M-J Gething ◽  
...  
Keyword(s):  
Plasminogen Activator ◽  
Plasminogen Activator Inhibitor ◽  
Tissue Type ◽  
Wild Type ◽  
Plasminogen Activator Inhibitor 1 ◽  
Tissue Type Plasminogen Activator ◽  
Type Plasminogen Activator ◽  
Pai 1

SummaryPlatelet-rich clots are inefficiently lysed by current fibrinolytic agents. Platelets contain a great deal of plasminogen activator inhibitor 1 (PAI-1), the principal endogenous inhibitor of tissue-type plasminogen activator (t-PA). We have tested whether PAI-1 resistant t-PAs would be more effective thrombolytic agents in an in vitro model of platelet rich clots. Clots were formed with recalcified human plasma without or with the addition of platelets. The lysis of these clots was followed by the release of incorporated 125I-fibrinogen. Mutant and wild-type t-PA were almost equally effective against clots lacking platelets but the mutant was twice as effective at lysing platelet-rich clots. A mechanism for this effect is suggested by the demonstration that a complex between wild-type t-PA and extruded platelet contents resembles that between purified t-PA and PAI-1 and that the PAI-1 resistant t-PA does not interfere with formation of this adduct. Because of its enhanced ability to lyse platelet-rich clots in vitro, further in vivo work may find that PAI-1 resistant t-PA is a more efficacious therapeutic agent than wild-type t-PA in situations where platelets contribute to the failure of thrombolysis.

scholarly journals Hormonal control of plasmin and tissue-type plasminogen activator activity in rat milk during involution of the mammary gland

2000 ◽  
Vol 167 (2) ◽  
pp. 265-273 ◽  
Author(s):  
E Tonner ◽  
GJ Allan ◽  
DJ Flint
Keyword(s):  
Mammary Gland ◽  
Growth Factor ◽  
Plasminogen Activator ◽  
Tissue Type ◽  
Plasminogen Activation ◽  
Insulin Like Growth Factor ◽  
Tissue Type Plasminogen Activator ◽  
Type Plasminogen Activator ◽  
Igf I ◽  
Pai 1

We have proposed that growth hormone (GH) and prolactin (PRL) interact to suppress apoptosis in the mammary gland. GH increases insulin-like growth factor-I (IGF-I) synthesis whereas PRL suppresses the production of insulin-like growth factor-binding protein-5 (IGFBP-5) in the epithelial cells, which would otherwise inhibit IGF-mediated cell survival. IGFBP-5 was present in milk from involuting glands at high concentrations (approximately 60 microg/ml) and had a high affinity (8.03 x 10(-10) M) for IGF-I, suggesting an inhibitory effect of IGFBP-5 in the mammary gland. IGFBP-5 was present in the micellar fraction of milk and binds specifically to alpha(s2)-casein. Since alpha(s2)-casein also binds plasminogen and tissue-type plasminogen activator (t-PA), resulting in the conversion of plasminogen to plasmin, and since IGFBP-5 binds to plasminogen activator inhibitor-1 (PAI-1), we investigated whether apoptosis and extracellular matrix (ECM) degradation might be coordinately controlled by GH and PRL possibly acting through IGFBP-5. Litters were removed from lactating rats to initiate involution. Plasminogen activation and t-PA activity were both increased dramatically after 48 h and GH and PRL suppressed this response. By contrast, 17beta-oestradiol, progesterone or corticosterone did not influence either process. An antiserum to IGF-I, which blocked systemic IGF-I effects, failed to inhibit the activation of plasminogen or the increase in t-PA, suggesting that paracrine effects of IGF-I may be more important. Teat-sealing, which led to the accumulation of milk without hormonal changes, also led to increases in plasminogen activation and t-PA activity, suggesting that locally produced factors (of which IGFBP-5 is one) are important in controlling ECM remodelling. We propose that GH and PRL inhibit apoptosis and ECM remodelling by a process that involves the control of IGF-I and PAI-1 availability by IGFBP-5, thus allowing these processes to be tightly coordinated.

scholarly journals Changes in the content of some components of the plasminogen activation system in the plasma of bladder cancer patients

2020 ◽  
Vol 80 (1) ◽  
pp. 15-19
Author(s):  
V. Dmytryk ◽  
O. Savchuk ◽  
P. Yakovlev
Keyword(s):  
Bladder Cancer ◽  
Blood Plasma ◽  
Plasminogen Activator ◽  
Tissue Type ◽  
Plasminogen Activation ◽  
Invasion And Metastasis ◽  
Plasminogen Activation System ◽  
Type Plasminogen Activator ◽  
Activation System ◽  
Pai 1

Bladder cancer (BC) continues to be a disease with a high mortality rate. Bladder cancer is the sixth for men and seventeenth for women in the incidence of malignancy worldwide. The invasion and metastasis of malignant tumors are caused by a sequence of processes, including loss of cell-cell and / or cell-matrix adhesion, proteolysis, and induction of angiogenesis. Different protease systems are involved in these processes, especially during the invasion and development of metastases. One such protease system is a plasminogen activation system or fibrinolysis system. Changes in the balance of plasminogen activation systems have been investigated in many types of malignancies, and these changes may not only indicate the functioning of this system but may also have prognostic significance. In malignancies, the components of this system are involved in the growth, invasion, and metastasis of tumors, affecting cell migration and angiogenesis. The main, but a well-studied component of the plasminogen activation system is serine proteinase – urokinase-type plasminogen activator (uPA). In contrast to uPA, tissue-type plasminogen activator (tPA) is characterized by a high affinity for fibrin and is involved in thrombolysis. Both types of plasminogen activators are synthesized in tumor tissues: tPA and uPA. The largest player among the inhibitors of fibrinolysis is the plasminogen activator inhibitor type 1 (PAI-1), involved in the pathogenesis of many cardiovascular diseases, as well as in cancer. The purpose of this study was to detect changes in the content of plasminogen activator tissue type tPA and PAI-1 in the blood plasma of patients with BC at different stages of the disease. The study involved 40 men who were verified with a diagnosis of BC. The content of tPA and PAI-1 in preoperative blood plasma was determined by enzyme immunoassay in ELISA modification. In our study, changes in the tPA and PAI-1 content of the blood plasma at different stages were identified, which can characterize tumor growth and invasion and can supplement existing disease information.

Immunoassay of Murine t-PA, u-PA and PAI-1 Using Monoclonal Antibodies Raised in Gene-inactivated Mice

1995 ◽  
Vol 74 (05) ◽  
pp. 1305-1309 ◽  
Author(s):  
Paul J Declerck ◽  
Maria Verstreken ◽  
Désiré J Collen
Keyword(s):  
Monoclonal Antibodies ◽  
Plasminogen Activator ◽  
Plasminogen Activator Inhibitor ◽  
Fold Increase ◽  
Tissue Type ◽  
Wild Type ◽  
Tissue Extracts ◽  
Type Plasminogen Activator ◽  
Murine Tissue ◽  
Pai 1

SummaryThree enzyme-linked immunosorbent assays for the quantitation of murine tissue-type plasminogen activator (t-PA), urokinase-type plasminogen aetivator (u-PA) and plasminogen activator inhibitor I (PAI-1), were developed using monoclonal antibodies raised against the autologous proteins in gene-inactivated mice. Dose-response was linear for t-PA and PAI-1 between 5 and 0.1 ng/ml and for u-PA between 50 and 1 ng/ml, with intra-assay, inter-assay and inter-dilution coefficients of variation of 6 to 14%. Assay recoveries of proteins (5 to 100 ng/ml) added to plasma were 73 to 95% for t-PA and PAI-1. Linear correlations (r = 0.65, r = 0.91 and r = 0.92, for t-PA, u-PA and PAI-1 respectively) were found between antigen and activity in plasma, urine and tissue extracts. Levels of t-PA and PAI-1 antigen in murine plasma were 2.5 ± 1.0 ng/ml (mean ± SD, n = 9) and 1.9 ± 0.6 ng/ml (mean ± SD, n = 8), respectively, in wild-type mice and undetectable in gene-inactivated mice. Bradykinin injection in mice provoked a 12-fold increase (p <0.0002) of t-PA and endotoxin injection an 80-fold increase (p <0.005) of PAI-1 levels. u-PA antigen levels in urine from wild-type mice ranged between 0.2 and 8.2 μ;g/ml (1.8 ± 1.9 μg/ml, mean ± SD, n = 17) and were undetectable in gene-inactivated mice.Thus, these assays may be useful for studies on the role of these proteins in tissue remodeling, atherosclerosis, embryogenesis, etc., in established mouse models. Gene-inactivated mice may constitute a general approach for the generation of monoclonal antibodies against the deficient translation products and for the development of specific immunoassays for murine proteins.

Recombinant Variants of Tissue-Type Plasminogen Activator Containing Amino Acid Substitutions in the Finger Domain

1992 ◽  
Vol 68 (06) ◽  
pp. 672-677 ◽  
Author(s):  
Hitoshi Yahara ◽  
Keiji Matsumoto ◽  
Hiroyuki Maruyama ◽  
Tetsuya Nagaoka ◽  
Yasuhiro Ikenaka ◽  
...  
Keyword(s):  
Amino Acid ◽  
Plasminogen Activator ◽  
Half Life ◽  
Tissue Type ◽  
Clot Lysis ◽  
Amino Acid Substitutions ◽  
Wild Type ◽  
Plasma Clot ◽  
Tissue Type Plasminogen Activator ◽  
Type Plasminogen Activator

SummaryTissue-type plasminogen activator (t-PA) is a fibrin-specific agent which has been used to treat acute myocardial infarction. In an attempt to clarify the determinants for its rapid clearance in vivo and high affinity for fibrin clots, we produced five variants containing amino acid substitutions in the finger domain, at amino acid residues 7–9, 10–14, 15–19, 28–33, and 37–42. All the variants had a prolonged half-life and a decreased affinity for fibrin of various degrees. The 37–42 variant demonstrated about a 6-fold longer half-life with a lower affinity for fibrin. Human plasma clot lysis assay estimated the fibrinolytic activity of the 37–42 variant to be 1.4-fold less effective than that of the wild-type rt-PA. In a rabbit jugular vein clot lysis model, doses of 1.0 and 0.15 mg/kg were required for about 70% lysis in the wild-type and 37–42 variant, respectively. Fibrinogen was degraded only when the wild-type rt-PA was administered at a dose of 1.0 mg/kg. These findings suggest that the 37–42 variant can be employed at a lower dosage and that it is a more fibrin-specific thrombolytic agent than the wild-type rt-PA.

A Specific Immunologic Assay for Functional Plasminogen Activator Inhibitor 1 in Plasma – Standardized Measurements of the Inhibitor and Related Parameters in Patients with Venous Thromboembolic Disease

1992 ◽  
Vol 68 (05) ◽  
pp. 486-494 ◽  
Author(s):  
Malou Philips ◽  
Anne-Grethe Juul ◽  
Johan Selmer ◽  
Bent Lind ◽  
Sixtus Thorsen
Keyword(s):  
Plasminogen Activator ◽  
Plasminogen Activator Inhibitor ◽  
Normal Subjects ◽  
Tissue Type ◽  
Blood Collection ◽  
Plasminogen Activator Inhibitor 1 ◽  
Type Plasminogen Activator ◽  
Significant Difference ◽  
Activator Inhibitor ◽  
Pai 1

SummaryA new assay for functional plasminogen activator inhibitor 1 (PAI-1) in plasma was developed. The assay is based on the quantitative conversion of PAI-1 to urokinase-type plasminogen activator (u-PA)-PAI-l complex the concentration of which is then determined by an ELISA employing monoclonal anti-PAI-1 as catching antibody and monoclonal anti-u-PA as detecting antibody. The assay exhibits high sensitivity, specificity, accuracy, and precision. The level of functional PAI-1, tissue-type plasminogen activator (t-PA) activity and t-PA-PAI-1 complex was measured in normal subjects and in patients with venous thromboembolism in a silent phase. Blood collection procedures and calibration of the respective assays were rigorously standardized. It was found that the patients had a decreased fibrinolytic capacity. This could be ascribed to high plasma levels of PAI-1. The release of t-PA during venous occlusion of an arm for 10 min expressed as the increase in t-PA + t-PA-PAI-1 complex exhibited great variation and no significant difference could be demonstrated between the patients with a thrombotic tendency and the normal subjects.

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