Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.4.21.73 (urokinase-type plasminogen activator)
 10,685 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Plasminogen activator inhibitor-1 (PAI-1), the primary inhibitor of tissue- and urokinase-type plasminogen activators, is considered a critical regulator of the fibrinolytic system. We previously reported a child with abnormal bleeding and complete PAI-1 deficiency caused by a frame-shift mutation in exon 4 of the PAI-1 gene. The purpose of this study was to provide genetic and clinical data on the extended pedigree of the original proband to better define the phenotype associated with PAI-1 deficiency. Allele-specific oligonucleotide hybridization was used to genotype individuals, and serum PAI-1 antigen was measured by enzyme-linked immunosorbent assay. By this approach we have identified 19 individuals who are heterozygous for the PAI-1 null allele and 7 homozygous individuals with complete PAI-1 deficiency. Clinical manifestations of PAI-1 deficiency were restricted to abnormal bleeding, which was observed only after trauma or surgery in homozygous affected individuals. A spectrum of bleeding patterns was observed, including intracranial and joint bleeding after mild trauma, delayed surgical bleeding, severe menstrual bleeding, and frequent bruising. Fibrinolysis inhibitors, including epsilon-aminocaproic acid and tranexamic acid, were effective in treating and preventing bleeding episodes. Other than abnormal bleeding, no significant developmental or other abnormalities were observed in homozygous PAI-1-deficient individuals. Heterozygous PAI-1 deficiency was not associated with abnormal bleeding, even after trauma or surgery. These observations define the clinical spectrum of PAI-1 deficiency and provide additional evidence to support the hypothesis that the primary function of plasminogen activator inhibitor-1 in vivo is to regulate vascular fibrinolysis.
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PMID:Human plasminogen activator inhibitor-1 (PAI-1) deficiency: characterization of a large kindred with a null mutation in the PAI-1 gene. 920 54

Plasminogen activator inhibitor-1 (PAI-1) cDNA was expressed in Escherichia coli (E. coli) with high efficiency using a heat-inducible vector. About 100 mg of recombinant PAI-1 (rPAI-1) could be obtained from 1 liter of bacteria culture. rPAI-1 in inclusion bodies was purified by pI precipitation and Sephadex G-75 chromatography. After treatment with 4 mol/L guanidinium chloride and dialysis, the largely inactive PAI-1 gained considerably in activity as judged by its reaction with low molecular weight u-PA (LMW-u-PA). Degenerated oligonucleotides containing ApaI site and mutations at Asp125, Glu128, Glu130 in PAI-1 cDNA were synthesized. To facilitate the introduction of mutations, an ApaI site was first generated in PAI-1 cDNA using one of the oligonucleotides. Taking advantage of the APaI site, thirteen PAI-1 mutants involving Asp125, Glu128 and Glu130 were produced with these oligonucleotides using PCR. Most of the PAI-1 mutants had a similar activity as compared to wild type PAI-1, while some of the triple-site mutants had completely lost their activity.
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PMID:High level expression of recombinant plasminogen activator inhibitor-1 in Escherichia coli and generation of its mutants involving Asp125, Glu128 and Glu130. 924 20

Plasminogen activator inhibitor-1 (PAI-1) is the primary physiological inhibitor of both tissue-type plasminogen activator (t-PA) and urokinase-type plasminogen activator (u-PA). Elevated plasma levels of PAI-1 have been associated with several important thrombotic diseases. A large number of studies have demonstrated that rats are suitable for in vivo investigations on thrombolysis and fibronolysis. In this study, we have expressed, in Escherichia coli, purified and characterized recombinant rat PAI-1 in comparison with human PAI-1. Subsequently this material was used to raise monoclonal antibodies using the hybridoma technology. Characterization of purified recombinant rat PAI-1 revealed that its functional and biochemical properties are similar to those of human PAI-1. Two fusions, with spleen cells from mice immunized with recombinant rat PAI-1, yielded 118 positive hybridomas. From these, 36 monoclonal antibodies were purified and evaluated for their applicability in the construction of sandwich-type ELISAs. Out of 860 combinations tested, 2 combinations were selected for the measurement of rat PAI-1 (antigen and activity) in biological samples (e.g., plasma, platelet lysates, cell-culture media, ...).
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PMID:Characterization of recombinant rat plasminogen activator inhibitor-1 and development of immunological tools for its quantitation. 931 43

The initial step in atherosclerosis is the rapid targeting of monocytes to the sites of inflammation and endothelial injury. Serum levels of intercellular adhesion molecule-1 were found to be increased in ischaemic heart disease patients and polymorphisms in the E-selectin gene were associated with accelerated atherosclerosis in young (age < 40 years) patients, further suggesting a role of inflammation in atherosclerosis. Cholesterol loading in macrophages was found to induce interleukin-8 expression, suggesting an association between foam cell formation and beta 2-integrin-dependent adhesion of leukocytes. Enhanced endothelium-platelet interaction induced by hypercholesterolaemia is mediated by von Willebrand factor, whereas platelet adhesion to subendothelial matrix is mediated by fibulin-fibrinogen complexes. Activated platelets mediate the homing of leukocytes by interaction with the subendothelial matrix under shear stresses that do not allow neutrophil adhesion. They may also contribute to the oxidative modification of LDL, provide a source of lipids for foam cell generation and contribute to smooth muscle cell proliferation. Oxidized LDL induces tissue factor in macrophages that also provide sites for fibrin polymerization and decreases the anticoagulant activity of endothelium by interfering with thrombomodulin expression and inactivating tissue factor pathway inhibitor. Intravascular fibrinolysis induced by tissue-type plasminogen activator or urokinase may contribute to the initiation of atherosclerosis by inducing P-selectin and platelet activating factor as well as to plaque rupture, either directly or indirectly, by activating metalloproteinases. Plasminogen activator inhibitor-1 inhibits smooth muscle cell migration and, in the presence of vitronectin, promotes the clearance of thrombin by LDL receptor-related protein at sites of endothelial injury.
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PMID:Thrombosis and atherosclerosis. 933 57

Induction of in vitro angiogenesis and upregulation of urokinase- and tissue type-plasminogen activator (uPA, tPA) expression are two hallmarks of vascular endothelial growth factor (VEGF) activity on cultured endothelial cells. We report here that neutralizing antibodies to basic fibroblast growth factor (bFGF) inhibit VEGF-induced in vitro angiogenesis in bovine microvascular endothelial (BME) cells. Analysis of VEGF receptor-2 (VEGFR-2) expression revealed no alteration in VEGFR-2 mRNA or total protein in anti-bFGF antibody-treated BME or bovine aortic endothelial (BAE) cells. Ethidium bromide/agarose gel electrophoresis on the cytosolic fraction of BME cells revealed a basal level of fragmented DNA that was increased by anti-bFGF antibodies to an extent not exceeding that observed in parallel cultures incubated with concentrations of transforming growth factor-ss1 that increase VEGF-induced in vitro angiogenesis. In both BME and BAE cells, antibodies to bFGF also decreased basal levels of cell-associated uPA activity, and completely blocked the VEGF-mediated increase in uPA and tPA expression observed in parallel cultures incubated with VEGF alone. In contrast, PA inhibitor-1 expression was strongly upregulated in BME and BAE cells incubated with antibodies to bFGF, either alone or in combination with VEGF. These findings demonstrate that: (1) VEGF-induced in vitro angiogenesis and PA expression are dependent on endogenous bFGF, (2) that this phenomenon is not mediated by a decrease in VEGFR-2 expression and that apoptosis does not necessarily correlate with inhibition of invasion, and (3) that inhibition of endogenous bFGF in VEGF-treated cells results in a net antiproteolytic (and possibly also anti-adherent) effect, which could account in part for the inhibitory effect of the anti-bFGF antibodies. These findings point to a novel and unsuspected role for endogenous bFGF in regulating VEGF-induced in vitro angiogenesis.
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PMID:Vascular endothelial growth factor-induced in vitro angiogenesis and plasminogen activator expression are dependent on endogenous basic fibroblast growth factor. 937 78

Tumor invasion and metastasis is mediated in part by proteolytic enzymes including urokinase plasminogen activator (uPA). The object of this study was to quantitate the molecular expression of urokinase plasminogen activator-related components in human superficial and invasive transitional cell carcinoma tumors (TCC), as well as parental and invasive variant TCC cell lines. We examined 15 invasive and 14 superficial TCC tumors (from a total of 29 patients) and six bladder carcinoma cell lines for the steady state mRNA levels of uPA, the uPA receptor and uPA inhibitor-1 by quantitative RT-PCR normalized to the L7 ribosomal transcript (a housekeeping gene). Transcript levels were expressed in a ratio to the L7 housekeeping transcript. There was a three fold increase in uPA expression in invasive lesions compared to superficial tumors (p < 0.003). In addition, there was a concordant 2.7 fold increase in the uPA receptor transcript in invasive TCC (p < 0.008). However, there was no significant difference in the steady state levels of the PAI-1 mRNA between invasive and superficial tumors. Transcript levels for the urokinase-related genes were similar between normal mucosa and superficial tumors. Cultured cells (parental and invasive variants) were found to express higher levels of the three uPA-related genes overall. Invasive TCC cells selected by serial passage through a Boyden chamber demonstrated higher levels of uPA, uPA receptor and PAI-1 than parental cells (p < 0.05). These data from the human tumor specimens suggest that increased uPA and uPAr expression may be component of the invasive phenotype of TCC lesions.
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PMID:The expression of urokinase-related genes in superficial and invasive transitional cell carcinoma. 945 2

Retinoic acid (RA) induces the activation of latent transforming growth factor-beta (TGF-beta) in bovine aortic endothelial cells (BAECs) via enhancement of cellular plasminogen activator (PA)/plasmin levels. The resultant TGF-beta suppresses the excessive fibrinolytic activity by decreasing PA expression and stimulating expression of the PA inhibitor, PA inhibitor-1 (PAI-1), and inhibits cell proliferation. Here, we report that, in this regulatory system, RA simultaneously up-regulates the expression of TGF-beta receptor types I and II, resulting in enhancement of TGF-beta activity in the cells. RA increased the numbers of high- and low-affinity binding sites for 125I-TGF-beta1 2.1-fold and 1.5-fold, respectively, without alteration of their Kd values. Affinity labeling and Western and Northern blotting studies showed that, following RA treatment, surface levels of both type I and type II receptors increased due to augmentation in their mRNA levels. The effect was dose- and time-dependent. Treatment with 1 microM RA for 15 hr increased mRNA levels of type I and II receptor threefold and eightfold, respectively. Pretreatment of BAECs with either RA or retinol lowered the concentration of TGF-beta1 required to suppress PA levels, to enhance PAI-1 levels, and to inhibit cell proliferation. Thus, retinoids may regulate cellular functions of BAECs not only by inducing the formation of active TGF-beta but also by stimulating TGF-beta receptor expression. This regulatory mechanism may sustain TGF-beta-mediated regulation of EC function at a focal site where RA is acting.
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PMID:Retinoids potentiate transforming growth factor-beta activity in bovine endothelial cells through up-regulating the expression of transforming growth factor-beta receptors. 969 9

In the present study, we determined the plasma and tissue concentrations of tissue-type plasminogen activator, urokinase-type plasminogen activator, plasminogen activator inhibitor-1, plasminogen activator inhibitor-2 and urokinase-type plasminogen activator receptor in 32 patients with pathology-proved gastric cancer. The plasma levels of the same markers were compared in 37 patients with benign gastric ulcer in order to find out if these plasma levels could be used to evaluate the prognostic value in patients with gastric cancer. Plasma plasminogen activator inhibitor-1 was significantly higher in gastric cancer than in benign gastric disease (p < 0.0005), whereas plasma urokinase-type plasminogen activator was significantly lower in patients with gastric cancer than in those with benign ulcer (p = 0.003). There was no significant correlation between tissue and plasma concentrations of the same parameters. The plasma and tissue levels of fibrinolytic parameters were not affected by tumor size or distant metastasis, whereas tumor tissue concentration of urokinase-type plasminogen activator receptor and plasminogen activator inhibitor-2 were significantly higher in N0 than in N1 and N2, and tissue plasminogen activator inhibitor-1 was significantly higher in N0 than in N1. Plasma levels of the five fibrinolytic parameters could not take the place of the corresponding tissue concentrations on the diagnosis and prediction of prognosis in patients with gastric cancer. Tissue concentrations of urokinase-type plasminogen activator receptor and plasminogen activator inhibitor-2, especially the latter, can be used to predict lymph node involvement in patients with gastric cancer.
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PMID:Diagnostic and prognostic values of plasma levels of fibrinolytic markers in gastric cancer. 970 Aug 49

In gastric cancer, the urokinase-type plasminogen activator (uPA) system plays important roles in invasion and metastasis, processes which entail proteolysis and adhesion. Both the urokinase-type plasminogen activator receptor (uPAR) and the plasminogen activator inhibitor-1 (PAI-1) are thought to be important factors in this system. To clarify the relationship between these two factors and gastric cancer invasiveness, we evaluated the expression of uPAR and PAI-1 in 91 cases of gastric cancer by immunohistochemistry and in situ hybridization. Urokinase-type plasminogen activator receptor-mRNA, PAI-1-mRNA, uPAR and PAI-1 protein were diffusely distributed in the cytoplasm of the cancer cells and concentrated at invasive foci. Urokinase-type plasminogen activator receptor protein expression correlated with lymphatic, venous invasion (P< 0.01) and lymph node metastasis (P< 0.05); uPAR-mRNA expression correlated with lymphatic, venous invasion and lymph node metastasis (P< 0.05). Plasminogen activator inhibitor-1 protein expression correlated with lymphatic, venous invasion, lymph node metastasis and depth of invasion (P<0.01); PAI-1-mRNA expression was linked to lymphatic, venous invasion (P< 0.01), lymph node metastasis and depth of invasion (P< 0.05). This suggests that the proteolytic activity of uPAR and the cellular motility of PAI-1 in gastric cancer cells may determine penetration of lymphatic and blood vessels, whereby lymph node metastasis may be promoted and that the promotion of cellular motility by PAI-1 may influence the depth of cancer invasion.
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PMID:Expression of urokinase-type plasminogen activator receptor and plasminogen activator inhibitor-1 in gastric cancer. 979 94

The plasminogen activator-plasmin system plays a pivotal role in the delicately regulated process of extracellular matrix remodeling. Recent studies have shown that an imbalance of proteolytic enzymes over specific inhibitors in this system may lead to an aggressive, expanding, and infiltrating cellular phenotype. As cholesteatoma resembles a tumor in many ways, we investigated the pattern of expression for members of the plasminogen activator-plasmin system in 12 human cholesteatomas, using immunohistochemistry. As controls, 3 tympanic membranes and 4 ear canal skin specimens were used. In contrast to the tympanic membranes, all cholesteatoma specimens showed a strong expression of plasminogen at the basal epithelial cell layers. In ear canal skin, only the basal surface of the most basal epithelia stained discretely positive. The urokinase-type plasminogen activator (uPA) could be detected in the basal stratum of the cholesteatoma matrix and in the surrounding granulation tissue, while tissue-type plasminogen activator (tPA) was not detectable at all. Plasminogen activator inhibitor-1 (PAI-1) was expressed in both the granulation tissue and the granular cell layer of the matrix, but not in the basal epithelial cells; PAI-2 showed a pericellular expression pattern in the subbasal and granular cell layers. Neither uPA, tPA, nor the PAIs could be detected in tympanic membrane controls; ear canal skin showed the same staining pattern as cholesteatoma only for PAI-2. Our data demonstrate that there is a clear imbalance in favor of proteolytic activity in the basal epithelial layers of the cholesteatoma matrix, which might at least partly account for the aggressive behavior of this tumorlike lesion. Further, the pattern of expression resembles the pattern described for several epithelial malignancies.
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PMID:Expression pattern of the plasminogen activator-plasmin system in human cholesteatoma. 1008 16


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