Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.4.21.68 (tissue plasminogen activator)
 11,311 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We investigated in vitro chemotactic responses to fibronectin and laminin, invasion through reconstituted basement membrane (Matrigel) and secretion of matrix metalloproteinases and plasminogen activators by non-tumorigenic Mel-ab melanocytes; B16 melanoma; and the metastatic sublines, B16F1, B16F10 and B16BL6. In vitro chemotactic and invasive ability were not associated with in vivo metastatic potential. Secretion of various matrix-degrading enzymes was not related to in vitro invasion. Conditioned media from all B16 melanoma sublines, but not from Mel-ab cells, contained the M(r) 92,000 progelatinase. The activated M(r) 85,000 species was present only in conditioned media from Mel-ab, B16 and B16F1 cells. Mel-ab cells secreted copious amounts of the M(r) 72,000 progelatinase, and the M(r) 66,000 active form was also present in conditioned media. Secretion of the M(r) 72,000 progelatinase by B16 melanoma sublines was markedly lower, and only conditioned media from B16 cells contained the activated M(r) 66,000 form. Furthermore, cell lysates of Mel-ab cells contained a M(r) 67,000 metalloproteinase which was absent in the tumor cells. All cells secreted tissue plasminogen activator; however, the metastatic B16F1, B16F10 and B16-BL6 cells also secreted urokinase plasminogen activator. Our results indicate that matrix metalloproteinase secretion by itself is not associated with tumorigenicity or metastatic potential. Secretion of urokinase plasminogen activator, and not tissue plasminogen activator, reflected the metastatic characteristics of the B16 melanoma tumor sublines.
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PMID:Differences in expression of metalloproteinases and plasminogen activators in murine melanocytes and B16 melanoma variants: lack of association with in vitro invasion. 755 59

Plasminogen activator inhibitor-1 (PAI-1), the primary inhibitor of tissue-type plasminogen activator (t-PA) and urokinase plasminogen activator, is an important regulator of the blood fibrinolytic system. Elevated plasma levels of PAI-1 are associated with thrombosis, and high levels of PAI-1 within platelet-rich clots contribute to their resistance to lysis by t-PA. Consequently, strategies aimed at inhibition of PAI-1 may prove clinically useful. This study was designed to test the hypothesis that a 14-amino acid peptide, corresponding to the PAI-1 reactive center loop (residues 333-346), can rapidly inhibit PAI-1 function. PAI-1 (0.7 microM) was incubated with peptide (55 microM) at 37 degrees C. At timed intervals, residual PAI-1 activity was determined by addition of reaction mixture samples to t-PA and chromogenic substrate. The T1/2 of PAI-1 activity in the presence of peptide was 4 +/- 3 min compared to a control T1/2 of 98 +/- 18 min. The peptide also inhibited complex formation between PAI-1 and t-PA as demonstrated by SDS-PAGE analysis. However, the capacity of the peptide to inhibit PAI-1 bound to vitronectin, a plasma protein that stabilizes PAI-1 activity, was markedly attenuated. Finally, the peptide significantly enhanced in vitro lysis of platelet-rich clots and platelet-poor clots containing recombinant PAI-1. These results indicate that a 14-amino acid peptide can rapidly inactivate PAI-1 and accelerate fibrinolysis in vitro. These studies also demonstrate that PAI-1 function can be directly attenuated in a physiologic setting and suggest a novel approach for augmenting fibrinolysis in vivo.
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PMID:Peptide-mediated inactivation of recombinant and platelet plasminogen activator inhibitor-1 in vitro. 773 6

The fibrinolytic potential of the endothelial cells gives important antithrombotic properties to the vascular wall. Thrombosis is a frequent complication to atherosclerosis and other conditions where inflammatory mediators are present in the vascular wall. Inflammatory agents like lipopolysaccharide (LPS) and tumor necrosis factor-alpha (TNF alpha) have been demonstrated to modulate the expression of fibrinolytic factors in cultured endothelial cells. In the present study the expression of tissue-type plasminogen activator (t-PA), urokinase plasminogen activator (u-PA) and plasminogen activator inhibitors-1 and -2 (PAI-1 and PAI-2) antigen in conditioned medium from cultured human umbilical vein (HUVEC) and human saphenous vein (HSVEC) endothelial cells was investigated under basal conditions and after stimulation with LPS, TNF alpha, interferon-gamma (IFN-gamma) or interleukin-6 (IL-6) alone or in combinations. Stimulation with LPS or TNF alpha increased the expression of PAI-1, u-PA and PAI-2 in HUVEC and HSVEC, while the t-PA response differed between the two cell types. The effects of TNF alpha were modulated by IFN-gamma but not by IL-6. The increased expression of u-PA after stimulation with TNF alpha was reduced by IFN-gamma. In contrast, TNF alpha-induced expression of PAI-2 was synergistically increased by addition of IFN-gamma. These effects of IFN-gamma represent additional mechanisms by which inflammatory mediators may turn the fibrinolytic potential of the endothelium in a prothrombotic direction.
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PMID:Interferon-gamma modulates the fibrinolytic response in cultured human endothelial cells. 777 58

To explore the role of transforming growth factor-beta (TGF beta) isoforms and other growth-related genes during prostate morphogenesis in the mouse, we examined mRNA levels in fetal day 17 urogenital sinus, mesenchyme (UGM), and epithelium (UGE) as well as in the ventral, dorsal, and anterior lobes of the adult prostate. In addition, we used antiserum specific for extracellular TGF beta 1 in immunohistochemical studies to localize accumulation of the TGF beta 1 isozyme in the above tissues as well as those derived from fetal day 19 and neonatal mouse prostate. Differential patterns of expression in fetal and adult tissues were seen. TGF beta 1, -beta 2, and -beta 3 expression was substantially elevated in UGM compared to that in UGE, yet only TGF beta 1, not TGF beta 2 or TGF beta 3, mRNA levels were sustained in adult prostate tissues. High levels of accumulation of TGF beta 1 were demonstrated by immunohistochemistry in the mesenchymal compartment compared to those in the epithelial compartment throughout development. Interestingly, the highest levels of TGF beta 1 appeared in areas of active epithelial duct formation and delineated the mesenchymal architectural changes necessary for ductal network formation. Additional studies revealed that levels of mRNAs for other genes involved in tissue remodeling and growth were also elevated in UGM compared to those in UGE. Tissue plasminogen activator, urokinase plasminogen activator, androgen receptor, and c-myc mRNA levels were also elevated in UGM compared to UGE. Interestingly, whereas tissue plasminogen activator mRNA levels, like those of TGF beta 2 and -beta 3, were barely detectable in adult prostatic tissues, mRNA levels for urokinase plasminogen activator, androgen receptor, and c-myc were readily detected and expressed in a lobe-specific fashion. Overall, these data indicate that expression of TGF beta 1 isoforms and other growth-related genes is associated with mesenchymal cells in areas of active morphogenesis during prostate development and provide objective molecular and cellular information regarding mediators of mesenchymal-epithelial interactions in prostate.
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PMID:Mesenchymal-epithelial interactions and transforming growth factor-beta expression during mouse prostate morphogenesis. 811 40

The pathophysiology of the cellular basis of radiation-induced demyelination and white-matter necrosis of the central nervous system (CNS) is poorly understood. Preliminary data suggest that tissue damage is partly mediated through changes in the proteolytic enzymes. In this study, we irradiated rat cervical spinal cords with single doses of 24 Gy of 18 MV photons or 20 MeV electrons and measured the levels of plasminogen activators at days 2, 7, 30, 60, 90, 120, 130 and 145 after irradiation, using appropriate controls at each time. Fibrin zymography revealed fibrinolytic bands representing molecular weights of 68,000 and 48,000 in controls and irradiated samples; these bands increased significantly at days 120, 130 and 145 after irradiation. Inhibition of these enzymatic bands with specific antibodies against tissue-type plasminogen activator (tPA) and amiloride, an inhibitor for urokinase plasminogen activator (uPA), confirmed that these bands were tPA and uPA. Enzymatic levels quantified by densitometry showed a twofold elevation in the levels of tPA and more than a tenfold increase in uPA after 120 days' irradiation. Activity of uPA was increased threefold by day 2 and increased steadily with time compared to nonirradiated control samples. Enzyme-linked immunosorbent assay (ELISA) also showed a threefold increase in the tPA content in the extracts of irradiated rat cervical spinal cords at days 120, 130 and 145. This study adds additional information to the proposed role of plasminogen activators in the pathogenic pathways of radiation damage in the CNS.
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PMID:Elevated levels of plasminogen activators in the pathogenesis of delayed radiation damage in rat cervical spinal cord in vivo. 818 13

The malignant potential of solid tumors is related to the ability to invade adjacent tissue and to metastasize. These properties of cancer cells depend on the synthesis of proteolytic enzymes which are able to digest adjacent connective tissue and basement membranes. We hypothesized that all elements of the plasminogen activation system might be overexpressed in malignant human breast tumors, functioning as an essential element in tumor invasion and metastasis. As determined by histopathological methods, the malignant tumors showed statistically significantly higher expression of urokinase plasminogen activator (uPA), type-1 plasminogen activator inhibitor (PAI-1), and especially urokinase plasminogen activator receptor (uPAR) than benign tissues. All those elements were present in higher amounts in the cancer cells than in the cells of benign or normal breast tissues. High exhibition of tissue plasminogen activator (tPA) found in cancer seems to be random and not related to the malignant or benign state, since benign and malignant tumors show overexpression of tissue plasminogen activator with similar frequency. When the tumors express high amounts of uPA, they express a high amount of uPAR in 50% of cases and PAI-1 in 57.3% of cases. When urokinase is expressed in low amount, the receptor is low in 28.6% and inhibitor in 21.4% of malignant breast tumors. This statistically significant consensus, 78.6% in the case of urokinase and its receptor and 78.6% in case of urokinase and its inhibitor, suggests that these activities may be the result of a unique mechanism of control, activated in the last steps of malignant transformation.
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PMID:Expression and localization of elements of the plasminogen activation system in benign breast disease and breast cancers. 822 86

Using immunohistochemistry and in situ hybridization, we have characterized the expression and localization of components of the plasminogen activator proteolytic cascade in an organotypic coculture system which consists of a "dermal" portion (human dermal fibroblasts throughout a collagen matrix) and a stratified, well-differentiated epidermal portion. Specifically, the following components were examined: the enzymes urokinase-type plasminogen activator and tissue-type plasminogen activator and their type 1 and type 2 inhibitors. Urokinase plasminogen activator mRNA and antigen were found predominantly in the least differentiated, basal keratinocytes; in some fields there was also faint deposition of antigen beneath the basal cells. The distribution of plasminogen activator inhibitor type 1 was similar to that of urokinase, except that inhibitor type 1 antigen deposition beneath the basal cells appeared more intense and uniform. In contrast to the results with urokinase plasminogen activator and inhibitor type 1, tissue plasminogen activator mRNA and antigen were localized focally in the suprabasal, i.e. more differentiated, keratinocytes. Plasminogen activator inhibitor type 2 mRNA and antigen were detected in most epidermal layers, but were more intense suprabasally and often spared the basal layer. These studies demonstrate that the same type of cell, i.e. the keratinocyte, can express different components of the plasminogen activator cascade depending on its state of differentiation. The change in expression of plasminogen activator cascade components with keratinocyte differentiation suggests distinct epidermal functions for these components, related to cell-matrix interaction and epidermal differentiation.
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PMID:Differential expression of plasminogen activators and their inhibitors in an organotypic skin coculture system. 827 Jun 42

Blackfoot disease is a unique endemic and chronic progressive arteriosclerotic vascular disease in southwest area of Taiwan. In this study, we determined the plasma levels of tissue plasminogen activator (tPA), plasminogen activator inhibitor (PAI), urokinase plasminogen activator (uPA), and von Willebrand factor (vWF) antigen in Blackfoot disease patients, in comparison with normal controls from non-endemic areas and the endemic area, Putai. Blackfoot disease patients had mean tPA antigen level of 7.9 ng/ml (n = 27) which was significantly lower (p < 0.05) than both the normal controls with 11.0 ng/ml (n = 20) and the Putai normal controls with 9.7 ng/ml (n = 39). However, the mean PAI-1 antigen level in the patient group was 41.2 ng/ml (n = 28) which was significantly higher (p = 0.0001) than both the normal controls with 19.7 ng/ml (n = 23) and the Putai normal controls with 21.3 ng/ml (n = 40). Furthermore, in the patient group, a significantly lower (p < 0.005) mean uPA antigen level (2.3 ng/ml, n = 18) was noted as compared with that in the normal controls (3.2 ng/ml, n = 14). No significant difference was observed in vWF antigen level between patients and normal controls. This study suggests that a reduced capacity for fibrinolysis is associated with Blackfoot disease.
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PMID:Impaired fibrinolysis in patients with Blackfoot disease. 830 60

The vascular endothelium plays a central role in the regulation of extrinsic fibrinolysis and thus maintains vascular patency through clot dissolution. Plasminogen activation provides an important source of localized proteolytic activity not only during fibrinolysis but also during a variety of other physiological and pathological processes. Numerous studies have indicated that human endothelial cells can directly synthesize and secrete plasminogen activators (PA) and inhibitors of these activators. PAs specifically hydrolyse a single arginine-valine bond in plasminogen, an abundant and widely distributed plasma zymogen, to form the broad spectrum serine protease, plasmin. Tissue type-PA (t-PA) and urokinase type PA (u-PA) forms of PA have been described in endothelial cells, although t-PA production and secretion is elevated most frequently. The tPA form of PA functions predominantly in endothelial cell mediated fibrinolysis, while uPA is involved in tissue remodeling. During inflammatory reactions activated mononuclear phagocytes produce a variety of cytokines which may influence the phenotype of the endothelium through a process termed "endothelial cell activation". Tumor necrosis factor alpha (TNF alpha), a mononuclear cytokine, is a distinct polypeptide of Mr 17,000 and has been implicated as a mediator of gram negative induced sepsis as well as angiogenesis. TNF alpha is known to interact with specific endothelial cell receptors and to alter endothelial coagulant and anticoagulant properties implying that cytokines may be potent modulators of hemostasis. Recent observations have indicated that TNF alpha and lymphotoxin (TNF beta) can promote the expression, synthesis and secretion of urokinase plasminogen activator (uPA) in human endothelial cells. The upregulation of uPA results in an alteration in the fibrinolytic capacity of endothelial cells and allows cells the selective ability to degrade and invade underlying subendothelial extracellular matrix (ECM). Endothelial cells treated with TNF alpha also display, in an in vitro angiogenic assay, the ability to invade Matrigel and reorganize into tube-like structures, unlike control cultures. The effects of TNF alpha on the PA proteolytic system of endothelial cells, the biological significance of this event and potential in vivo consequences will be discussed. In addition, the influence of cytokine regulatory control systems will be described, since it is becoming increasingly clear that cytokines do not act in isolation. The vascular endothelium serves as a widely distributed anatomical interface between the blood and tissue with diverse capabilities, performing distinctive biologic functions at different sites and within specific organs.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Cytokine regulation of endothelial cell extracellular proteolysis. 835 23

In Vienna, Austria, health workers took blood samples from 16 healthy, nonsmoking 19-35 year old women before and after they began using a combined oral contraceptive (OC) (Gynovin) (30 mcg ethinyl estradiol and 75 mcg gestodene) to assess the OC's effects on blood coagulation and fibrinolysis and the effect of the estrogen component on endothelial cells. Fibrinogen levels increased significantly after OC use (283 mg/dl vs. 342 mg/dl after the 1st treatment cycle; p .005). These levels remained significantly higher (326 mg/dl and 339 mg/dl after the 2nd and 3rd treatment cycles; p .005 and .05, respectively). Thrombin antithrombin III complex (TAT) and prothrombin fragment F1+2 levels increased just minimally during OC treatment. Levels of fibrin split-product D-dimer, plasma tissue plasminogen activator (t-PA) activity, and plasmin-antiplasmin (PAP) complexes were significantly higher during all OC treatment cycles than they were before treatment. Active plasminogen activator inhibitor (PAI-1) antigen, t-PA, and urokinase plasminogen activator antigen levels fell significantly after OC treatment and remained low during OC treatment. Experiments with the culture of human umbilical vein endothelial cells showed that ethinyl estradiol did not significantly affect the tissue factor content or surface thrombomodulin activity of these endothelial cells (i.e., hemostatic regulatory activities). It also did not change the secretion of the fibrinolytic components t-PA and PAI-1. None of the women developed thrombosis. Even though these findings did not clearly show OC-induced hemostatic activation in this relatively small group of women, clinical researchers should still determine activation markers to monitor the activation state of blood coagulation in certain OC users, such as obese women and those who smoke cigarettes.
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PMID:Studies on oral contraceptive-induced changes in blood coagulation and fibrinolysis and the estrogen effect on endothelial cells. 839 73


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