Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P00750 (PLA)
 16,800 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The effects of tumor necrosis factor (TNF)-alpha on the plasminogen activator (PA)/plasmin system in human dental pulp (HDP) cells were examined. TNF-alpha treatment induced a significantly high level of PA activity in the conditioned medium of HDP cells in a time- and dose-dependent manner, compared with untreated control cells. Western-blot analysis revealed that tissue type (t)PA protein in conditioned medium was increased by TNF-alpha when compared with control medium. Furthermore the tPA mRNA level had increased in HDP cells treated with TNF-alpha, as determined by reverse transcription-polymerase chain reaction, but urokinase PA and PA inhibitor-1 mRNA levels did not increase. We examined the effects of TNF-alpha against activities of matrix metalloproteinases (MMPs) using zymography. TNF-alpha stimulated MMP-2 activity in conditioned medium and stimulated MMP-9 activity with addition of plasminogen into conditioned medium. The present results suggested that TNF-alpha stimulates PA activity via an enhancement of tPA gene expression in HDP cells and MMP-2 activity, and further that tPA-activated TNF-alpha stimulated MMP-9.
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PMID:Stimulation of plasminogen activator activity and matrix metalloproteinases of human dental pulp-derived cells by tumor necrosis factor-alpha. 1148 46

Proteases are linked to the malignant phenotype of different solid tumors. Therefore, the expression of the matrix metalloproteinase (MMP)-2 and MMP-9 and of the serine protease urokinase-type plasminogen activator (uPA) and its inhibitor plasminogen activator inhibitor type 1 (PAI-1) in the progression of ovarian cancer was investigated. Gelatinolytic activity and protein expression of MMP-2 and MMP-9 were analyzed in tissue extracts of 19 cystadenomas and 18 low malignant potential (LMP) tumors, as well as 41 primary tumors of advanced ovarian cancer stage International Federation of Gynecology and Obstetrics IIIc/IV and their corresponding omentum metastases by quantitative gelatin zymography and Western blot. In the same tissue extracts, antigen levels of uPA and its inhibitor PAI-1 were determined by ELISA. Protein expression of pro-MMP-2 (72 kDa) and pro-MMP-9 (92 kDa as well as antigen levels of uPA and PAI-1 were low in benign ovarian tumors but increased significantly from LMP tumors to advanced ovarian cancers. The highest values of all of the proteolytic factors were detected in omentum metastases. Active MMP-2 enzyme (62 kDa) was detected only in ovarian cancer (66%) and corresponding metastases (93%) but never in benign or LMP tumors. The activation rate of MMP-2 to its active isoform was higher in the metastases. Comparing both proteolytic systems, higher PAI-1 concentrations were consistently found in cancers with high pro-MMP-9 expression. These data indicate that members of the plasminogen activator system, as well as the metalloproteinases MMP-2/9, increase with growing malignant potential of ovarian tumors. These findings are of particular relevance to the development of protease inhibitors as new therapeutic approaches in ovarian cancer.
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PMID:Increased expression of matrix metalloproteinases (MMP)-2, MMP-9, and the urokinase-type plasminogen activator is associated with progression from benign to advanced ovarian cancer. 1148 18

Degradation of the extracellular matrix leads to the release of fragments, which elicit biological responses distinct from intact molecules. We have reported that alpha1:Ser(2091)-Arg(2108), a peptide derived from the alpha1-chain of laminin-1, triggers protein kinase C-dependent activation of MAPK(erk1/2), leading to the up-regulation of macrophage urokinase type plasminogen activator and matrix metalloproteinase (MMP)-9 expression. Since intact laminin-1 failed to trigger these events, we hypothesized that alpha1:Ser(2091)-Arg(2108) is cryptic or assumes a conformation not recognized by macrophages. Here we demonstrate that elastase cleavage of laminin-1 generates fragments, which stimulate proteinase expression by RAW264.7 macrophages and peritoneal macrophages. In contrast, fragments generated by MMP-2, MMP-7, or plasmin had no effect on macrophage proteinase expression. Elastase-generated laminin-1 fragments were fractionated by heparin-Sepharose chromatography. Heparin-binding fragments stimulated macrophages' proteinase expression severalfold greater than nonbinding fragments. The heparin binding fragments reacted with antibodies directed against regions of the alpha1-chain including alpha1:Ser(2091)-Arg(2108) and the globular domain. A peptide from the first loop of the globular domain (alpha1:Ser(2179)-Ser(2198)) triggered the phosphorylation of MAPK(erk1/2) and stimulated the expression of macrophage urokinase type plasminogen activator and MMP-9. Moreover, a heparin-binding fraction isolated from an aortic aneurysm contained fragments of alpha1-chain and stimulated macrophages' proteinase expression. Based on these data, we conclude that cryptic domains in the COOH-terminal portion of the alpha1-chain of laminin are exposed by proteolysis and stimulate macrophages' proteinase expression.
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PMID:Exposure of cryptic domains in the alpha 1-chain of laminin-1 by elastase stimulates macrophages urokinase and matrix metalloproteinase-9 expression. 1182 68

Transforming growth factor beta-1 (TGF-beta1) is secreted in a biologically inactive form and stored in the extracellular matrix as a 290 kDa complex consisting of the mature TGF-beta1 homodimer (Mr 25 kDa), the latency-associated peptide (LAP; Mr 75 kDa), and the latent TGF-beta1 binding protein-1 (LTBP1; Mr 190 kDa). Latent TGF-beta1, composed of these three components, is known as the "large latent TGF-beta1 complex." In contrast, latent TGF-beta1 without LTBP1 is known as "small latent TGF-beta1." For all latent forms, dissociation of the TGF-beta1 homodimer from LAP is necessary for growth factor activation and acquisition of biological activity. Matrix vesicles produced by growth plate chondrocytes contain matrix metalloproteinases that can activate small latent TGF-beta1. The enzyme responsible for this is matrix metalloproteinase-3 (MMP-3), although matrix vesicles also contain MMP-2 and plasminogen activator. The present study tested the hypothesis that matrix vesicle enzymes are also involved in the release of the large latent TGF-beta1 complex stored in the extracellular matrix. Matrix vesicles were isolated from cultures of resting zone and growth zone chondrocytes and metalloproteinases present in the matrix vesicles extracted with guanidine-HCl. Chondrocyte extracellular matrices were prepared by lysing confluent cultures and removing the lysed cells. The matrices were incubated with matrix vesicle extracts and the release of total and active TGF-beta1 was determined. To determine if MMP-2 or MMP-3 was involved in the release, matrix vesicle extracts were preincubated with anti-MMP-2 antibody or anti-MMP-3 antibody to selectively deplete the enzyme activity. Matrices were also treated with rhMMP-2 or rhMMP-3. To determine the identity of the released protein(s), digests were separated on SDS-polyacrylamide gels and Western blotting analysis was performed using a specific antibody to LTBP1. Matrix vesicle extracts released both active and total (=latent + active) TGF-beta1 in a time-dependent manner, with peak release after 1 hour of incubation. The amount of total TGF-beta1 released was 10 times higher than the release of active TGF-beta1. The effect of the matrix vesicle extracts was dose-dependent; in addition, the amount and ratio of active to total TGF-b1 released was very similar, irrespective of the source of matrix or matrix vesicle extracts. Pre-incubation of matrix vesicle extracts with anti-MMP-3 antibody blocked the release of active and total TGF-beta1, whereas pre-incubation with pre-immune IgG or anti-MMP-2 antibody had no effect. The addition of rhMMP-3, but not rhMMP-2, caused a dose-dependent increase in the release of total, but not active, TGF-beta1. Western analysis confirmed that both matrix vesicle extracts and rhMMP-3 released the large latent TGF-beta1 complex from the matrix. In addition to the expected 290, 230, and 190 kDa bands, samples run without reduction also contained proteins of molecular weights 110 and 50 kDa that reacted with the anti-LTBP1 antibody. When these same samples were electrophoresed after reduction, the high molecular weight immunoreactive bands disappeared and three bands of molecular weight 75, 32, and 25 kDa were observed. These results indicate that matrix vesicles contain enzymes, especially MMP-3, which are responsible for the release of TGF-beta1 from the matrix, most of which is in latent form. Further, the data suggest that release of the large complex occurs via cleavage at several novel sites in the 130 kDa LTBP1 molecule. Since matrix vesicle MMP-3 is also able to activate small latent TGF-beta1, these results suggest that the large latent TGF-beta1 complex protects against activation of the small latent TGF-beta1. Thus, the data suggest that release of the large latent TGF-bl complex from the matrix and activation of the latent growth factor are only two steps of what must be at least a three-step process.
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PMID:The first stage of transforming growth factor beta1 activation is release of the large latent complex from the extracellular matrix of growth plate chondrocytes by matrix vesicle stromelysin-1 (MMP-3). 1190 8

Fischer rat thyroid (FRT) cells organize a matrix of extracellular fibronectin (FN) fibrils, which undergoes extensive remodeling according to cell culture confluence. In non-confluent cells FN forms a fibrillar array associated with the ventral cell surface. However, basal FN is progressively removed in confluent cultures and substituted by non-fibrillar FN deposits at lateral cell domains in regions of cell-cell contacts. FRT cells secrete and expose on the plasma membrane the tissue-type plasminogen activator and, in serum-free cultures, plasminogen induces a rapid loss of FN fibrils. Incubation with plasmin inhibitors greatly reduces this effect. FRT cells also express annexin II, a plasminogen receptor, suggesting that plasmin activity is associated with the pericellular enviroment. This is in agreement with the observation that a great reduction in FN degradation is observed if the cells are pre-incubated with carboxypeptidase B, which prevents plasminogen binding to the cells. A gelatinolytic activity with a molecular weigth equivalent to MMP-2 has been demonstrated by zymography of culture media, and the presence of MMP-2 and MT1-MMP on the cell plasma membrane has been detected by immunofluorescence. These results indicate that in the FN remodeling process, occurring during FRT epithelium maturation, both plasmin-dependent (tPA activated) and plasmin-independent proteolytic activities are involved.
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PMID:The role of proteases in fibronectin matrix remodeling in thyroid epithelial cell monolayer cultures. 1192 11

A fragment of rat thoracic aorta within type I collagen gel was employed as a model of angiogenesis, including the processes of cell migration, proliferation and capillary tube formation. Endogenous angiogenic factors in this model were studied. Expressions of vascular endothelial growth factor (VEGF) and its receptor, and proteolytic enzyme activities (matrix metalloprotease-2; MMP-2 and plasminogen activator; PA) increased during angiogenesis. The angiogenesis was inhibited by VEGF receptor kinase inhibitor and MMP inhibitor, confirming that these endogenous factors played an important role in angiogenesis. Interestingly, these inhibitors induced different capillary morphologies, including differences of cell migration and sprouting. Furthermore, dexamethasone (a down-regulator of MMP and PA) and TNP-470 (an endothelial cell growth inhibitor) induced another capillary morphology. The results suggest that the capillary structure in this model is dramatically influenced by the inhibition of angiogenic signalling and extracellular matrix (ECM) degradation. We also found that a novel angiogenesis inhibitor, the microbial metabolite luminacin, which was recently identified by us (Wakabayashi et al., J. Antiobiot., 53, 591-596 (2000)), induced a different morphology compared with other inhibitors examined, suggesting that it has a unique mechanism of action. Our results indicate that this rat aorta model should be useful for screening novel angiogenesis inhibitors.
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PMID:Characterization of rat aortic fragment within collagen gel as an angiogenesis model; capillary morphology may reflect the action mechanisms of angiogenesis inhibitors. 1199 22

A nutritionally induced obesity model was used to investigate the modulation of fibrinolytic and gelatinolytic activity during the development of adipose tissue. Five week old male mice were fed a standard fat diet (SFD, 13% kcal as fat) or a high fat diet (HFD, 42% kcal as fat) for up to 15 weeks. The HFD resulted in body weights of 31 +/- 0.9 g, 38 +/- 2.0 g and 47 +/- 1.9 g at 5, 10 and 15 weeks, respectively; corresponding values for mice on the SFD were 26 +/- 0.6 g, 31 +/- 0.9 g and 31 +/- 1.2 g (all p < 0.001). The weight of the isolated subcutaneous (s.c.) or gonadal (GON) fat after 15 weeks of HFD was 1,870 +/- 180 mg or 1,470 +/- 160 mg, as compared to 250 +/- 58 mg or 350 +/- 71 mg for the SFD (p < 0.001). The HFD induced marked time-dependent hyperglycemia and elevated levels of triglycerides and total cholesterol. The HFD diet also induced a marked hypertrophy of the adipocytes as compared to the SFD, e.g. diameter of 83 +/- 3.0 microns versus 52 +/- 4.2 microns for GON adipocytes at 15 weeks (p < 0.005). Plasma plasminogen activator inhibitor-1 (PAI-1) levels were higher in mice on the HFD as compared to the SFD; they were comparable in extracts of s.c. or GON adipose tissue, whereas at different time points tissue-type (t-PA) and urokinase-type (u-PA) plasminogen activator activity was somewhat lower in the adipose tissues of mice on HFD. Gelatinolytic activity (mainly MMP-2) was detected in s.c. but not in GON adipose tissue of mice on SFD, and decreased on the HFD. In situ zymography on cryosections did not reveal different fibrinolytic activities in s.c. or GON adipose tissues of the HFD as compared to the SFD groups, whereas significantly lower gelatinolytic and higher caseinolytic activities were detected in s.c. and GON tissues of mice on the HFD (p < or = 0.05). The fibrillar collagen content was lower in adipose tissue of mice on HFD. Thus, in this model time-dependent development of adipose tissue appears to be associated with modulation of proteolytic activity.
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PMID:Modulation of fibrinolytic and gelatinolytic activity during adipose tissue development in a mouse model of nutritionally induced obesity. 1219 10

We studied the role of the adventitia in adaptive arteriogenesis during the phase of active growth of coronary collateral vessels (CV) induced by chronic occlusion of the left circumflex coronary artery in canine hearts. We used electron microscopy and immunoconfocal (IF) labeling for bFGF, matrix metalloproteinase (MMP)-2, MMP-9, tissue-type plasminogen activator (tPA), its inhibitor (PAI-1), fibronectin (FN), and Ki-67. Proliferation of smooth muscle cells and adventitial fibroblasts was evident. Quantitative IF showed that adventitial MMP-2, MMP-9, and FN were 9.2-, 7.5-, and 8.6-fold, bFGF was 5.1-fold, and PAI-1 was 3.4-fold higher in CV than in normal vessels (NV). The number of fibroblasts was 5-fold elevated in CV, but the elastic fiber content was 25-fold greater in NV than in CV. Perivascular myocyte damage and induction of endothelial nitric oxide synthase in peri-CV capillaries indicate expansion of CV. It was concluded that adventitial activation is associated with the development of CV through cell proliferation, production of growth factors, and induction of extracellular proteolysis thereby contributing to remodeling during adaptive arteriogenesis.
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PMID:Remodeling of the adventitia during coronary arteriogenesis. 1238 38

We examined the role of matrix metalloproteinases (MMPs), tissue inhibitors of MMP (TIMPs), and plasminogen activator (PA) in transmyocardial laser revascularization (TMLR)-induced angiogenesis. TMLR was accomplished with a carbon dioxide laser in seven dogs whose left anterior descending coronary artery (LAD) was ligated. Seven control dogs underwent only LAD ligation, and four dogs underwent a sham operation, consisting only of a left thoracotomy. Two weeks later, transmural myocardial samples were harvested from the distributions of the LAD and the left circumflex artery for substrate zymography, immunohistochemical staining, and in situ zymography. MMP-1, MMP-2, TIMP-1, TIMP-2, and urokinase-type PA levels in the distribution of the LAD were higher in the laser group than in the control or sham group. Counts of von Willebrand factor-positive microvessels and smooth muscle alpha-actin-positive arterioles demonstrated that the angiogenesis and ateriogenesis was promoted in the laser group and correlated directly with the number of MMP-stained microvessels. We conclude that TMLR induces the expression of MMPs, TIMPs, and urokinase-type PA and that these proteinases play an important role in angiogenesis after TMLR.
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PMID:Role of MMPs and plasminogen activators in angiogenesis after transmyocardial laser revascularization in dogs. 1238 87

Acquired abdominal aortic aneurysms are usually associated with a mural thrombus through which blood continues to flow. Some early data suggest that aneurysmal evolution correlates with the biological activity of the thrombus. Our hypothesis was therefore that the thrombus could adsorb blood components and store, release, and participate in the activation of proteases involved in aneurysmal evolution. For this purpose, we have explored both the metalloproteinase and fibrinolytic systems in the thrombus and the wall of human aneurysms. We have first investigated blood clot formation and lysis in vitro. Spontaneous clotting induces a release of promatrix metalloproteinase (pro-MMP)-9 into the serum that was fourfold higher than in paired control plasma (P < 0.001). Fibrinolysis progressively released more MMP-9 in a time-dependent manner (P < 0.01). After selective isolation, we demonstrated that polymorphonuclear leukocytes are the main source of MMP-9 release during clot formation. Protease content was then analyzed in 35 mural thrombi and walls of human abdominal aortic aneurysms sampled during surgical repair. In 15 aneurysms, the liquid phase at the interface between the thrombus and the wall was sampled separately. Both thrombus and wall contained MMP-2 and MMP-9 but the ratio MMP-9/MMP-2 was higher in the thrombus than in the wall. The liquid interface also contained active MMP-9. Immunohistochemistry of the thrombus confirmed these findings, showing the presence of polymorphonuclear leukocytes at the luminal pole of the thrombus, co-localizing with MMP-9 storage. In contrast, MMP-3 and MMP-7 were only present in the aneurysmal wall. Plasminogen was present in the mural thrombus but plasmin activity was present in both thrombus and wall. In the liquid interface, plasmin-alpha(2)-anti-plasmin complexes were detected demonstrating in vivo the activation of plasminogen. In contrast, u-PA and t-PA were detectable only in the wall, suggesting that plasminogen present in the thrombus could be activated by factors secreted by the arterial wall. This was demonstrated in vitro, in which co-incubation of thrombus and wall extracts generated plasmin in the presence of a fibrin matrix and activated MMPs. In conclusion, our study strongly suggests that the mural thrombus, by trapping polymorphonuclear leukocytes and adsorbing plasma components could act as a source of proteases in aneurysms that may play a critical role in enlargement and rupture.
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PMID:Involvement of the mural thrombus as a site of protease release and activation in human aortic aneurysms. 1241 17


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