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

Microvascular endothelial cells (RFCs) cultured in two-dimensional (2D) cultures proliferate rapidly and exhibit an undifferentiated phenotype. Addition of transforming growth factor beta1 (TGFbeta1) increases fibronectin expression and inhibits proliferation. RFCs cultured in three-dimensional (3D) type I collagen gels proliferate slowly and are refractory to the anti-proliferative effects of TGF beta1. TGF beta1 promotes tube formation in 3D cultures. TGF beta1 increases fibronectin expression and urokinase plasminogen activator (uPA) activity and plasminogen activator inhibitor-1 (PAI-1) levels in 3D cultures. Since the TGF beta type I and II receptors have been reported to regulate different activities induced by TGF beta1, we compared the TGF beta receptor profiles on cells in 2D and 3D cultures. RFCs in 3D cultures exhibited a significant loss of cell surface type II receptor compared with cells in 2D cultures. The inhibitory effect of TGF beta1 on proliferation is suppressed in transfected 2D cultures expressing a truncated form of the type II receptor, while its stimulatory effect on fibronectin production is reduced in both 2D and 3D transfected cultures expressing a truncated form of the type I receptor. These data suggest that the type II receptor mediates the antiproliferative effect of TGF beta1 while the type I receptor mediates the matrix response of RFCs to TGF beta1 and demonstrate that changes in the matrix environment can modulate the surface expression of TGF beta receptors, altering the responsiveness of RFCs to TGF beta1.
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PMID:Modulation of transforming growth factor beta receptor levels on microvascular endothelial cells during in vitro angiogenesis. 861 76

Urokinase receptors (uPAR; CD87) from complexes with complement receptor 3 (CR3) (CD11b/CD18), a beta2 integrin. In this study, we sought to determine if this association modulates the adhesive function of CR3. Both CR3 and uPAR concentrate at the ventral surface of fibrinogen-adherent human monocytes, and CR3-uPAR coupling increases substantially upon adhesion to fibrinogen. Pretreatment with anti-uPAR monoclonal antibody reduced adhesion to CR3 counterligands (fibrinogen and keyhole limpet hemocyanin) by 50%, but did not affect adhesion to fibronectin, a beta1 integrin counterligand. Antisense (AS) oligonucleotides were used to determine if selectively suppressing uPAR expression also modulates CR3 adhesive function. AS-uPAR oligo reduced CR3-dependent adhesion by 43+/-9% (P<0.01), but did not affect CR3-independent adhesion. To determine if the effects of uPAR are mediated through its ligand, monocytes were pre-treated with AS oligo to block uPA expression. Unlike the effects of blocking uPAR expression, AS-uPA oligo increased adhesion by 46% (P<0.005), and exogenous intact uPA, but not uPA fragments, reversed this effect. We conclude that complex formation with uPAR facilitates the adhesive functions of CR3. This function of uPAR is not dependent upon its occupancy with uPA, which negatively influences adhesion.
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PMID:The urokinase receptor (CD87) facilitates CD11b/CD18-mediated adhesion of human monocytes. 862 79

We characterized a new mammary tumor cell line, F3II, previously established in vitro from a clonal subpopulation of the BALB/c transplantable mammary adenocarcinoma M3, moderately metastatic to lung. The F3II cell line has been passaged > 50 times. It has grown as elongated cells adherent to the bottom of the flask. Cytogenetic studies showed that F3II cultures were nearly triploid. Tumor cells expressed fibronectin and showed high levels of cell-surface urokinase, a key protease in invasion and metastasis. F3II cells grew as poorly differentiated, spindle-cell carcinoma tumors (sarcomatoid carcinomas) with a prominent local invasiveness, a high angiogenic response, and a 90-100% incidence of lung metastases when inoculated s.c. into syngeneic mice. Ultrastructural and immunocytochemical analysis revealed characteristic features of carcinomas. Our data suggest that F3II is less differentiated and more aggressive than the original tumor line, supporting the notion that mammary carcinomas are heterogeneous neoplasms and contain subpopulations with diverse biologic behavior. The F3II mouse mammary sarcomatoid carcinoma line is a suitable model to examine antiinvasive, antiangiogenic, and antimetastatic agents.
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PMID:Characterization of F3II, a sarcomatoid mammary carcinoma cell line originated from a clonal subpopulation of a mouse adenocarcinoma. 869 44

Matrilysin (MAT) is a member of the matrix metalloproteinase (MMP) family which is believed to degrade components of the extracellular matrix (ECM) during processes of tissue remodeling. Although MAT is similar to the stromelysins in its substrate specificity, and to interstitial collagenase in the crystal structure of its catalytic domain, this enzyme is unique in that it lacks the carboxy-terminal segments encoded by other MMP genes. Characterization of the human MAT gene has revealed that the promoter region contains typical MMP promoter elements such as AP-1 and PEA3, which mediate responsiveness to growth factors, oncogenes, and phorbol esters. Activated recombinant forms of human MAT cleave ECM and basement membrane proteins such as fibronectin, collagen type IV, laminin, and particularly elastin, entactin, and cartilage proteoglycan aggregates. Furthermore, MAT appears to mediate the proteolytic processing of other molecules (e.g. tumor necrosis factor alpha precursor, urokinase plasminogen activator). MAT is expressed in a variety of tumors ranging from adenomas to carcinomas and adenocarcinomas of the breast, colon, prostate, stomach, upper aerodigestive tract, lung, and skin, where it may be involved in tumor formation as well as the tissue degradation which accompanies tumor cell extravasation. Localization of MAT mRNA and protein to the tumor cells is unusual in that the majority of MMPs are produced in the stroma. This distinctive tissue-restricted pattern of MAT expression is a recapitulation of the expression pattern in normal human tissue, where MAT protein localizes to secretory and ductal epithelium in the endometrium and in various exocrine glands. In the mouse, high constitutive levels of MAT mRNA are found in epithelial cells in the uterus, small intestine, and extra-testicular ducts. Taken together, these findings suggest that MAT may have a specific role in normal gland and organ function, a possibility which can be explored further by the genetic manipulation of MAT levels in vivo.
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PMID:Matrilysin: an epithelial matrix metalloproteinase with potentially novel functions. 872

Tumor cells produce urokinase-type plasminogen activator (uPA) in an enzymatically inactive proenzyme form (pro-uPA). Secreted pro-uPA can immediately bind to the specific uPA receptors (uPAR) on tumor cell surface with high affinity. The uPAR specifically recognizes enzymatically inactive pro-uPA and active high molecular weight-uPA (HMW-uPA) by their growth factor-like terminal domain. uPAR is a glycoprotein of approximately 55 kDa; the affinity for uPA is high (0.2 nM) and the rate of dissociation is low. Receptor-bound uPA catalizes the formation of plasmin on the cell surface to generate the proteolytic cascade that contributes to the breakdown of basement membrane and extracellular matrix. The plasma membrane uPAR has attracted considerable attention because of its role in migration and tissue invasion by mononuclear phagocytes and malignant cells. In some cell types uPAR localizes uPA to cell-cell and cell-substratum contact sites, providing the possibility of a directional proteolysis that may be involved in cell migration and invasion. Recently it has been reported that competitive displacement of uPA from uPAR resulted in decreased proteolysis, suggesting that the cell surface is the preferred site for uPA-mediated protein degradation. Various very different approaches to interfere with the expression or reactivity of uPA or uPAR at the gene or protein level were successfully tested including antisense oligonucleotides, antibodies, inhibitors and recombinant or synthetic uPA and uPAR analogues. Recently we have reported that a highly purified urinary trypsin inhibitor (UTI) efficiently inhibits soluble and tumor cell-surface receptor-bound plasmin. UTI inhibits not only tumor cell invasion in an in vitro assay but also production of experimental and spontaneous lung metastasis in an in vivo mouse model. The anti-invasive effect is dependent on the anti-plasmin activity of UTI. UTI peptide, which inhibits plasmin activity, synthesized by an automated peptide synthesizer showed mouse 3LL cell invasion inhibitory activity. UTI and the effective peptide inhibited tumor cell invasion through Matrigel. UTI did not inhibit tumor cell proliferation or the binding of the cells to Matrigel. Also, UTI did not inhibit chemotactic migration of tumor cells to fibronectin. It is likely that UTI acts as a protease inhibitor. We attempted to synthesize conjugates between ATF and UTI. Thus, conjugating a physiological plasmin inhibitor to ATF might target it to reduce cell-associated proteolytic activity to the close environment of the uPAR-expressing tumor cell surface and subsequently may effectively inhibit tumor cell invasion and metastasis, because the cell surface uPAR might be a critical component of the metastatic machinery. A method of conjugation of the UTI domain II (HI-8), to the receptor-binding amino-terminal fragment (ATF) of uPA has been developed utilizing the heterobifunctional cross-linking reagent, N-succinimidyl-3-(2-pyridyldithio) propionate (SPDP). The conjugate retained its protease inhibiting activity and showed a binding reactivity to uPAR on the surface of tumor cells. We have shown that the conjugate exhibits plasmin inhibition to the close environment of the cell surface and subsequently inhibits the tumor cell invasion through Matrigel in an in vitro invasion assay. In order to extend our idea, we attempt to produce a novel hybrid molecule consisting of the ATF of uPA placed at the N-terminus of UTI domain II (HI-8) by protein engineering techniques. Exogenously applied ATFHI hybrid protein can immediately bind to the specific uPAR on cell surfaces with high affinity. The receptor-bound hybrid protein focuses the protease-inhibiting activity to the tumor cell surface. This is effectively a bifunctional molecule which, in addition to inhibiting trypsin and plasmin activities directly, is able toblock unoccupied uPAR, thereby preventing localization of uPA activity.
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PMID:[Mechanism of tumor cell-induced extracellular matrix degradation--inhibition of cell-surface proteolytic activity might have a therapeutic effect on tumor cell invasion and metastasis]. 880 30

Since thromboembolic complications in transplanted patients are generally attributed to combined abnormalities in platelets and coagulo-lytic system, some hemostatic parameters tPA (tissue plasmogin activator):Ag and activity, its inhibitor-PAIAg and activity, tPA/PAI, thrombin-antithrombin (TAT) and plasmin-antiplasmin complexes (PAP), urokinase-uPA, euglobulin clot lysis time-ECLT, fibrinogen, plasminogen, protein C activity, D-dimer, prothrombin fragments1+2 (F1+2), fibrin monomers, fibronectin, lipoprotein-a, and von Willebrand factor(vWF), were evaluated using commercially available kits. The studies were performed on kidney transplant recipients treated with CsA, azathioprine and prednisone (n=21), and healthy volunteers (n=21). ECLT was significantly prolonged in kidney transplant recipients together with a rise in F1+2,lipoprotein-a, fibrinogen, fibronectin, and vWF when compared with controls. The TPA level was lower, whereas the PAI level was higher in kidney transplant recipients when compared with controls. In conclusion, CsA-treated kidney transplant recipients show evidence of pronounced impairment in fibrinolysis and endothelial damage in comparison with healthy volunteers.
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PMID:The coagulo-lytic system and endothelial function in cyclosporine-treated kidney allograft recipients. 882 84

The effect of transforming growth factor-beta (TGF-beta) was analyzed on the synthesis of fibronectin, collagen type IV, and urokinase plasminogen activator in human glomerular epithelial cells in culture. An increase in the abundance of specific mRNA was found for collagen type IV and fibronectin. Fibronectin protein synthesis was also increased in TGF-beta treated cells; most of the de novo synthesized fibronectin was found as an unsoluble protein associated with extracellular matrix. In the same cells the amount of plasminogen activator mRNA was found leading also to a decreased surface expression of urokinase plasminogen activator. The data support the concept that by upregulating matrix protein synthesis and downregulating the plasminogen activator system, TGF-beta favors the development of sclerosis.
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PMID:Interaction of transforming growth factor beta 1 with human glomerular epithelial cells in culture: opposite effects on synthesis of matrix proteins and on urokinase plasminogen activator. 884 65

A pathogenetic role for fibrin deposition and platelet activation in the kidney is thought to play a role in the pathogenesis of acute renal failure (ARF). Thus, some fibrinolytic parameters and platelet function have been studied in 17 patients with ARF and compared to healthy volunteers and subjects with chronic renal failure (CRF). Since serotonin may participate in pathological processes resulting from platelet/vessel wall interactions, its level in the whole blood and plasma was also assayed. In ARF and CRF platelet aggregatory responses in both whole blood and in platelet rich plasma upon stimulation with various agonists (collagen, arachidonic acid, ADP, ristocetin) were lower than those obtained in healthy volunteers. Increased levels of lipoprotein (a), von Willebrand factor (vWF) and fibronectin were found in ARF relative to controls. Protein C activity was significantly lower in patients with ARF. Euglobulin clot lysis time was prolonged in ARF and CRF, reflecting a decreased overall fibrinolytic activity. Activity of tissue plasminogen activator (tPA) inhibitor (PAI) and PAI:Ag were higher in ARF, whereas tPA:Ag, urokinase, tPA/PAI complexes, thrombin-antithrombin complexes (TAT), plasmin-antiplasmin (PAP) complexes, fibrinogen, and F1+2 did not differ between ARF and controls. In CRF elevated levels of TAT, PAP, fibrinogen and prothrombin fragments F1+2 were found, whereas concentration of fibronectin was lowered when compared to controls. In both groups of renal failure patients increased levels of fibrin monomers and d-dimer were found relative to healthy volunteers. Whole blood serotonin was significantly lower, whereas plasma serotonin was significantly higher in patients with ARF and CRF relative to controls. Serotonin uptake and its release from platelets were markedly diminished in patients with ARF and CRF. Chronic renal failure exhibit a slightly different pattern of coagulopathies that acute renal failure.
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PMID:Hemostasis, platelet function and serotonin in acute and chronic renal failure. 887 44

Addition of proteolytically generated fibronectin fragments (Fn-f) to cultured cartilage tissue causes greatly enhanced release of metalloproteinases (MMPs), such as pro-stromelysin-1 (proSln-1), and suppression of proteoglycan (PG) synthesis, through release of catabolic cytokines, while native fibronectin is ineffective. We have investigated whether enhanced release of proSln-1 was due to up-regulation of pro-Sln-1 mRNA. We report the addition of a 29-kDa (amino-terminal heparin-binding Fn-f) or a 140-kDa (central cell-binding Fn-f) to bovine chondrocytes in monolayer culture causes a dose dependent increase in the expression of pro-Sln-1 mRNA and the greatly enhanced release of pro-Sln-1 protein into the culture media. Up to 700 nM pro-Sln-1 was found in the conditioned media and metabolic labeling showed that it constituted a major portion of newly synthesized protein. A potential activator of pro-Sln-1, urokinase (u-PA), was released at elevated levels in the presence of the Fn-f while other activators, tissue plasminogen activator (t-PA) and plasmin activities were not detected. Addition of these activators to conditioned media did not allow conversion of pro-Sln-1 to active Sln-1. However, aminophenyl mercuric acid activated pro-Sln-1 to a 48-kDa Sln-1 form capable of degrading PG when added to cartilage suspensions. Gelatinase A mRNA was also enhanced, suggesting that the Fn-f may induce MMPs in general. However, the major regulator of Sln-1 activity, tissue inhibitor of MMPs form 1 (TIMP-1), was not induced at the gene level. Thus, a major effect of Fn-f on chondrocytes is to up-regulate pro-Sln-1 expression at the gene level, resulting in pro-Sln-1 as a major protein product.
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PMID:Fibronectin fragments induce the expression of stromelysin-1 mRNA and protein in bovine chondrocytes in monolayer culture. 887 27

Abnormalities in lipid metabolism appear to play a pathogenic role in progressive renal disease. To elucidate the cellular and molecular basis of renal interstitial fibrosis in uninephrectomized rats with diet-induced hypercholesterolemia, we fed experimental rats with standard rat chow supplemented with 4% cholesterol and 1% cholic acid. Control rats were fed an isocaloric diet. Groups of 7 control and 7 experimental rats were killed after 4, 8, and 12 weeks. Hypercholesterolemic rats developed albuminuria; serum creatinine was elevated at 12 weeks. By 12 weeks numerous oil red O-positive cells were present throughout the interstitium and to a lesser extent in tubules. Total renal lipid-peroxidation products were significantly increased (172 +/- 15, 198 +/- 28, and 197 +/- 13 mmol malondialdehyde/kidney at 4, 8, and 12 weeks vs. 123 +/- 17, 144 +/- 6, and 125 +/- 10 mmol in controls). Immunostaining revealed oxidatively modified lipoproteins within tubular and interstitial cells. The interstitial disease was characterized by an interstitial infiltrate of monocytes. Significant increases were detected in renal cortical mRNA levels for monocyte chemoattractant protein-1 (MCP-1), osteopontin, and vascular cell adhesion molecule-1 (VCAM-1), associated with changes in the pattern of immunostaining for each encoded proteins. Total kidney collagen was significantly increased at 12 weeks (9.8 +/- 0.9 mg/kidney vs. 7.8 +/- 0.9 mg in controls). At 12 weeks there was a significant increase in interstitial immunostaining for collagen I, collagen III, collagen IV, fibronectin and tenascin. A significant threefold increase in renal cortical mRNA levels for transforming growth factor beta-1 (TGF-beta 1) at 4 and 12 weeks was associated with the appearance of TGF-beta 1-positive interstitial cells. Renal matrix protein mRNA levels were measured at 4, 8, and 12 weeks. The only statistically significant elevations were procollagen alpha 1(I) and procollagen alpha 1(III) at weeks 8 and 12. In contrast, renal cortical mRNA levels for the tissue inhibitor of metalloproteinases-1 (TIMP-1) were significantly increased at 4, 8 and 12 weeks (1.4 +/- 0.5, 2.7 +/- 0.9 and 2.7 +/- 1.4 arbitrary densitometric units, respectively, vs. 1.0 +/- 0.4, 1.0 +/- 0.5 and 1.0 +/- 0.4 units for controls), and urokinase-type plasminogen activator (muPA) mRNA levels were significantly decreased at 4, 8, and 12 weeks (0.4 +/- 0.1 arbitrary densitometric units for all three experimental groups vs. 1.0 +/- 0.4, 1.0 +/- 0.3, and 1.0 +/- 0.4 units for the control groups). In summary, rats with diet-induced hypercholesterolemia develop renal interstitial fibrosis over several weeks. Following the accumulation of lipids within tubulointerstitial cells, interstitial nephritis develops. The fibrotic phase is characterized by modest changes in matrix protein mRNA levels, up-regulated TIMP-1, and down-regulated muPA levels, suggesting that altered matrix degradation plays a role in the interstitial fibrogenesis in this model.
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PMID:Interstitial inflammation and fibrosis in rats with diet-induced hypercholesterolemia. 888 71


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