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)

Muscle cell migration plays an important role in the incorporation of transplanted myoblasts in muscle fibers. Understanding the mechanisms underlying the high migration capacity of the C(2)C(12) myoblast cell line may help to develop approaches to improve the migration of normal myoblasts and consequently to increase their participation to the host myofiber regeneration. We have previously shown that matrix metalloproteinases are implicated in the in vivo migration of C(2)C(12). Here, we studied the role of urokinase plasminogen activator (uPA) in this process. The expression of uPA mRNA and the enzymatic activity of uPA were studied in both normal myoblasts and the C(2)C(12) myoblast cell line. Reverse transcriptase polymerase chain reaction analysis showed that uPA mRNA was more strongly expressed in C(2)C(12) cells than in normal myoblasts. The enzymatic activity of secreted uPA analyzed by casein zymography is higher in medium conditioned by C(2)C(12) cells than in medium conditioned by normal myoblasts. Using our previously described microtube technique to assess in vivo cell migration, we showed that uPA is implicated in the in vivo migration of C(2)C(12) cells since this migration was abrogated in the presence of aprotinin (a general serine protease inhibitor) or amiloride (a uPA-specific inhibitor). We, therefore, hypothesized that increasing endogenous uPA expression by normal myoblasts may improve their migration capacity. Since an accumulating body of evidence has shown that growth factors regulate expression of uPA in a wide range of cells, we treated normal myoblasts with several growth factors alone or in combination with components of the extracellular matrix (ECM). All stimulants tested showed a minimal to strong effect on uPA enzymatic activity as assayed by zymography analysis. The positive effect of basic fibroblast growth factor (bFGF) on uPA enzymatic activity was slightly potentiated in the presence of fibronectin. Moreover, the pretreatment and coinjection of mouse myoblasts with bFGF alone or in combination with fibronectin improved significantly their in vivo migration throughout the tibialis anterior muscle of mdx mice. These results suggest that increasing uPA expression by an appropriate combination of growth factors and ECM components constitutes a possible approach to improving the migration of myogenic cells after transplantation.
 ...
PMID:The urokinase plasminogen activator: an interesting way to improve myoblast migration following their transplantation. 1241 83

The proteolytic activity in chloroform-treated plasma euglobulins has been attributed to plasmin. Plasmin can digest both casein and fibrin. Epsilon aminocaproic acid, which inhibits the activation of plasminogen, the precursor of plasmin, by streptokinase, urokinase, and tissue activators enhanced the development of casein hydrolytic activity in a mixture of chloroform and plasma euglobulins. Fibrinolytic activity was also enhanced, but this was evident only if the epsilon aminocaproic acid was removed from the chloroform-treated euglobulins prior to assay. The reasons for the paradoxical enhancement of chloroform-induced casein hydrolysis by euglobulins containing epsilon aminocaproic acid are unclear. However, studies of optimal pH, heat stability, and the effect of ionic strength on the activation of the precursor of this proteolytic enzyme do not differentiate it from plasminogen.
 ...
PMID:The enhancement of chloroform-induced plasma proteolytic activity by epsilon aminocaproic acid. 1388 79

1. On subcellular fractionation of rabbit kidney by differential and density-gradient centrifugation, a high proportion of the tissue activator of plasminogen activity was found to be particulate and displayed sedimentation properties associated with the lysosome-rich fraction as judged biochemically by the acid-phosphatase activity. 2. The activator activity is closely associated with a latent protease whose activity is enhanced in the presence of Triton X-100 or sodium deoxycholate in the neutral pH range. Besides hydrolysing casein this protease is also capable of attacking fibrinogen at pH7.4. 3. The pH optimum for activator activity and its inhibition by in-hexanoic acid (in-aminocaproic acid) point to its possible similarity to urokinase, an activator of plasminogen present in the urine of most mammals.
 ...
PMID:STUDIES ON THE TISSUE ACTIVATOR OF PLASMINOGEN. DISTRIBUTION OF ACTIVATOR AND PROTEOLYTIC ACTIVITY IN THE SUBCELLULAR FRACTIONS OF RABBIT KIDNEY. 1434 53

Previous studies have shown that the urokinase-type plasminogen activator receptor (uPAR) is localized to the adherence sites of leukocytes and tumor cells suggesting that pericellular proteolysis may accompany focal activation of adherence. To assess for focused pericellular proteolytic activity, we prepared two-dimensional substrates coated with FITC-casein or Bodipy FL-BSA. These molecules are poorly fluorescent, but become highly fluorescent after proteolytic degradation. Fluorescent peptide products were observed at adherence sites of stationary human neutrophils and at lamellipodia of polarized neutrophils. During cell migration, multiple regions of proteolysis appeared sequentially beneath the cell. Similarly, proteolytic action was restricted to adherence sites of resting HT1080 tumor cells but localized to the invadopodia of active cells. Using an extracellular fluorescence quenching method, we demonstrate that these fluorescent peptide products are extracellular. The uPA/uPAR system played an important role in the observed proteolytic activation. Plasminogen activator inhibitor-1 significantly reduced focal proteolysis. Sites of focal proteolysis matched the membrane distribution of uPAR. When uPA was dissociated from uPAR by acid washing, substantially reduced pericellular proteolysis was found. uPAR-negative T47D tumor cells did not express significant levels of substrate proteolysis. However, transfectant clones expressing uPAR (for example, T47D-26) displayed high levels of fluorescence indicating proteolysis at adherence sites. To provide further evidence for the role of the uPA/uPAR system in pericellular proteolysis, peritoneal macrophages from uPA knock-out (uPA-/-) and control (uPA+/+) mice were studied. Pericellular proteolysis was dramatically reduced in uPA-negative peritoneal macrophages. Thus, we have: (1). developed a novel methodology to detect pericellular proteolytic function, (2). demonstrated focused activation of proteolytic enzymatic activity in several cell types, (3). demonstrated its usefulness in real-time studies of cell migration, and (4). showed that the uPA/uPAR system is an important contributor to focal pericellular proteolysis.
 ...
PMID:Pericellular proteolysis by leukocytes and tumor cells on substrates: focal activation and the role of urokinase-type plasminogen activator. 1504 74

Remodeling of the extracellular matrix (ECM) occurs during antral follicle growth, and the plasminogen activators (PA) have been implicated in this process in rodents. In the present study, we measured the expression and secretion of PA and the PA inhibitor protease nexin-1 (SerpinE2) in antral and basal bovine granulosa cells from small (<6 mm), medium (6-8 mm), and large follicles (>8 mm) during 6 days of culture in serum-free medium. Casein zymography revealed that the cells secreted predominantly tissue-type PA (tPA) with urokinase (uPA) being associated mainly with cell lysates, and Western blot demonstrated that the cells secreted SerpinE2. Overall, secreted tPA activity was higher in cultures of cells from small follicles compared with large follicles, and secreted SerpinE2 levels were higher in cultures of cells from large follicles. In cultures of cells from small follicles, secreted tPA levels increased with time of culture for antral but not basal cells, and SerpinE2 levels increased with time for basal but not antral cells. In cultures of granulosa cells from large follicles, tPA activity increased significantly with time of culture, whereas SerpinE2 levels decreased. Cell-associated uPA activity decreased with time in cells from medium and large follicles. Reverse-transcription polymerase chain reaction and Northern blot analysis showed that SerpinE2 secretion was regulated largely at the transcriptional level, whereas tPA secretion was not. The data suggest stage-dependent regulation of granulosa cell PA and SerpinE2 production, consistent with a role in ECM remodeling during follicle growth.
 ...
PMID:Plasminogen activator and serine protease inhibitor-E2 (protease nexin-1) expression by bovine granulosa cells in vitro. 1512 99

Cancer metastasis, involving multiple processes and various cytophysiological changes, is a primary cause of cancer death and may complicate the clinical management, even lead to death. Silibinin is a flavonoid antioxidant and wildly used for its antihepatotoxic properties and recent studies have revealed pleiotropic anticancer and antiproliferative capabilities of silibinin. In this study, we first observed that silibinin exerted a dose- and time-dependent inhibitory effect on the invasion and motility, but hardly on the adhesion, of highly metastatic A549 cells in the absence of cytotoxicity. To look at the precise involvement of silibinin in cancer metastasis, A549 cells were treated with silibinin at various concentrations, up to 100 microM, for a defined period and then subjected to gelatin zymography, casein zymography and Western blot to investigate the impacts of silibinin on metalloproteinase-2 (MMP-2), urokinase plasminogen activator (u-PA), and tissue inhibitor of metalloproteinase-2 (TIMP-2), respectively. The results showed that a silibinin treatment may decrease the expressions of MMP-2 and u-PA in a concentration- and time-dependent manner and enhance the expression of TIMP-2. Further analysis with semi-quantitative RT-PCR showed that silibinin may regulate the expressions of MMP-2 and u-PA on the transcriptional level while on the translational or post-translational level for TIMP-2.
 ...
PMID:Silibinin inhibits the invasion of human lung cancer cells via decreased productions of urokinase-plasminogen activator and matrix metalloproteinase-2. 1522 46

Plasminogen activation is believed to be critical to the progression of oral squamous cell carcinoma by facilitating matrix degradation during invasion and metastasis, and high levels of urokinase plasminogen activator (uPA) and plasminogen activator (PA) inhibitor-1 (PAI-1) in tumors predict poor disease outcome. We describe the development of a novel method for studying PA in oral cancer that combines the sensitivity and specificity of zymography with the spatial resolution of immunohistochemistry. Laser capture microdissection (LCM) was combined with plasminogen-casein zymography to analyze uPA, tissue PA (tPA), uPA-PAI-1 complexes, and tPA-PAI-1 complexes in 11 tumors and adjacent non-malignant epithelium from squamous cell carcinomas of the tongue, floor of mouth, larynx, and vocal cord. uPA was detectable in all tumor samples analyzed, uPA-PAI-1 complexes in three samples, and tPA in nine. PA was detectable in as little as 0.5 microg protein lysate from microdissected tumors. In all specimens, uPA expression was highly increased in tumor tissue compared to adjacent non-malignant tissue. In conclusion, LCM combined with zymography may be excellently suited for analyzing the prognostic significance and causal involvement of the plasminogen activation system in oral cancer.
 ...
PMID:Detection of plasminogen activators in oral cancer by laser capture microdissection combined with zymography. 1550 94

A hallmark of parasitic meningitis is the infiltration of eosinophils into the subarachnoid space. Infection with Angiostrongylus cantonensis in mice induced proteinase activity in parallel with the pathological changes of eosinophilic meningitis. Zymogram analysis demonstrated that 70 and 55 kDa proteinases from cerebrospinal fluid (CSF) were active against the casein/plasminogen substrate. The proteinase activities were clearly inhibited by phenylmethanesulphonyl fluoride but not by ethylenediamine tetraacetic acid, 1,10-phenanthroline or leupeptin. Western blotting confirmed these enzymes to be tissue-type plasminogen activator and urokinase-type plasminogen activator, respectively. High activities of tissue-type plasminogen activator and urokinase-type plasminogen activator were detected in the CSF of mice with eosinophilic meningitis, and correlated positively with CSF eosinophil numbers and total protein, respectively. Immunohistochemistry demonstrated that tissue-type plasminogen activator and urokinase-type plasminogen activator localised in the endothelial cells of blood vessels, in blood clots and in infiltrated leukocytes. These results suggest that tissue-type plasminogen activator and urokinase-type plasminogen activator may be play a role in the pathogenesis of eosinophilic meningitis of angiostrongyliasis.
 ...
PMID:Elevation of plasminogen activators in cerebrospinal fluid of mice with eosinophilic meningitis caused by Angiostrongylus cantonensis. 1554 96

The aim of this study was to investigate the effects of different doses of exogenous recombinant human tissue plasminogen activator (rt-PA) on the endogenous cerebral plasminogen-plasmin system in focal ischemia in rats. Ischemia was induced using the suture model. Each group of rats (n = 6) received either treatment (0.9, 9 or 18 mg rt-PA/kg body weight) or saline (control group) at the end of ischemia; a sham-operated group was added. The activity of the plasminogen activators was measured by casein-dependent plasminogen zymography. In the cortex urokinase (u-PA) rose from sham (no ischemia), 91 +/- 7% to ischemia, 176 +/- 10% (P < 0.005). Increasing rt-PA doses led to further significant (P < 0.001) cortical u-PA activation which was maximal at 18 mg: 249 +/- 13%. An extreme increase in the u-PA activity was observed in the basal ganglia to 1019 +/- 22% (P < 0.001). This increase was further aggravated by higher rt-PA doses (18 mg, 1236 +/- 15%; P < 0.001). The t-PA level did not change I3R24 during (3 h ischemia followed by reperfusion for 24 h); however, during low and moderate doses of rt-PA, endogenous t-PA was reduced. In conclusion, while ischemia leads to a significant increase in u-PA, mainly in the basal ganglia, t-PA is not altered. Increasing doses of rt-PA lead to a further elevation of u-PA. Thus, u-PA seems to play a major role in the endogenous plasminogen activator system following focal cerebral ischemia.
 ...
PMID:Rt-PA causes a significant increase in endogenous u-PA during experimental focal cerebral ischemia. 1557 44

In mammalian females, follicular units arise from the fragmentation of ovigerous cords, which spread over the first three postnatal days in the rat. The mechanisms underlying such a process of epithelial remodeling involve a specific balance between basal membrane (BM) deposition and degradation that has as yet not been precisely described. We have investigated the contribution of proteases in BM remodeling by localization of transcripts, protein, or enzymatic activity. In addition, we have analyzed BM deposition at the ultrastructural level and by immunofluorescence detection of BM components. At birth, when fragmentation occurred, epithelial cells displayed an upregulation of membrane type 1-matrix metalloproteinase (MT1-MMP) and urokinase-type plasminogen activator (uPA), as well as laminin alpha1 mRNAs. Although MMP2 expression was restricted to mesenchymal cells throughout development, in situ zymography showed that gelatinase-MMP2 activity colocalized with BM deposition inside deepening clefts in the areas of ovigerous cord fragmentation. In the days following birth, gelatin and plasminogen-casein zymography showed an increased enzymatic activity of MMP2 and uPA, respectively. In organotypic cultures of 21-day postconception ovaries, serine protease inhibitors like aprotinin could efficiently block follicle histogenesis. In addition, our results show that the well described and great wave of oocyte attrition characteristic of the days following birth closely correlates with BM remodeling. Altogether, our data show that during follicle histogenesis, ovigerous cord fragmentation results from an acute BM component deposition in deepening clefts and that BM homeostasy involves proteinases of the MMP2/MT1-MMP/TIMP3 and plasminogen/uPA families.
 ...
PMID:Basal membrane remodeling during follicle histogenesis in the rat ovary: contribution of proteinases of the MMP and PA families. 1561 83


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>