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)

We report on the effect of prolonged hyperglycaemic (11 and 30 mM D-glucose) culture conditions on human mesangial cell matrix metalloproteinases (MMPs), plasminogen activators and their inhibitors. The results indicate that hyperglycaemic conditions modulate the potential proteolytic activity of the enzymes secreted by confluent cultures of these cells. Gelatinase A (MMP-2) activity was always higher in cultures maintained under hyperglycaemic than under normoglycaemic conditions (4 mM D-glucose). In contrast, gelatinase B (MMP-9) activity was decreased under the same conditions. Matrilysin (MMP-7) activity was decreased by up to 100% under hyperglycaemic conditions. Reverse transcriptase-PCR and Western-blotting analyses indicate that in all cases both the transcripts and the protein level were correlated with enzymic activity. One tissue inhibitor of metalloproteinases, TIMP-2, was barely detectable under hyperglycaemic conditions (30 mM D-glucose). In contrast, TIMP-1 increased during the initial 2 weeks of culture in hyperglycaemic conditions and remained elevated to the end of the experiment (4 weeks). Under normoglycaemic conditions TIMP-1 decreased after 2 weeks of culture. Hyperglycaemic conditions also decreased markedly the activity of tissue plasminogen activator (t-PA). This seemed to be due to increased synthesis of its inhibitor, plasminogen activator inhibitor 1, under these conditions rather than to decreased expression of the t-PA enzyme.
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PMID:Modulation of neutral protease expression in human mesangial cells by hyperglycaemic culture. 900 62

The role of extracellular proteolysis in inflammatory demyelination, originally hypothesized as a mechanism for myelin degradation, is increasingly recognized as a pathogenetic step and as a target for therapy in human demyelinating disease. The activation of ubiquitous plasminogen by urokinase (u-PA) and tissue-type plasminogen activator (t-PA), which is associated with various neuropathologies, including multiple sclerosis (MS), is the key initiator of the activation cascade of the four classes of matrix metalloproteinases (MMPs): collagenases, stromelysins, membrane-type metalloproteinases and gelatinases. Spatiotemporal protein and mRNA expression of gelatinase B (MMP-9) and matrilysin (MMP-7) have been documented respectively in MS lesions and in the central nervous system (CNS) of animals developing experimental autoimmune encephalomyelitis (EAE). A close interaction between disease-promoting cytokines and extracellularly acting proteases is deduced from in vitro experiments. Cytokines regulate the balance between the proteases and their respective specific inhibitors at the transcriptional level, while proteolysis is a reciprocal mechanism to enhance (by activation) or downmodulate (by degradation) the specific activities of cytokines. In acute inflammation the contribution of chemokines is hierarchically organised, interleukin-8 (IL-8) and related CXC-chemokines inducing a rapid influx of neutrophils in the acute lesions and an instantaneous exocytosis of gelatinase B granules. This results in sudden and extensive damage to the CNS. In chronic disease involving autoimmune processes CC-chemokines that act mainly on mononuclear cell types appear to be more strictly regulated. As MMPs modify matrix components, promoting extravasation of lymphocytes and monocytes/macrophages and have the potential to generate encephalitogenic peptides from myelin basic protein, novel treatments for demyelinating diseases may be predicted by specific inhibition of these enzymes. Here we review plasminogen activators and the MMP family, in the context of their role in CNS inflammation and demyelination and highlight studies in which intervention in these protease cascades are and may be used to treat demyelinating diseases.
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PMID:Plasminogen activators and matrix metalloproteases, mediators of extracellular proteolysis in inflammatory demyelination of the central nervous system. 1037 31

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

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

When SW620 colon cancer-derived metastatic cells were exposed to nanomolar concentrations of Taxol, colchicine or (Z)-3,5,4'-trimethoxystilbene (R3), huge aneuploid, polynuclear cells survived the treatment. These cells released considerable amounts of the matrix metalloproteinase matrilysin (MMP-7), and tissue-type plasminogen activator (tPA) into the surrounding culture medium. MMP-7, and other proteolytic enzymes were highly expressed by these cells. In spite of their enormous size, the polyploid cells exhibited a considerable migratory capacity, as was demonstrated by their migration through an artificial basement membrane. While colchicine and R3-treated cells showed an inverse relationship between drug concentration and invasiveness, treatment with Taxol increased the capacity of the SW620 cells to penetrate through the membrane. The invasive capacity was not correlated with the induction and release of proteolytic enzymes. The idea that expression and release of proteolytic enzymes is a fundamental prerequisite of tumour cell invasiveness is generally accepted. The ability of the cells to respond to chemotactic signalling, and the filamentous structures of the cells, together with several cell adhesion factors, which are the basis of cell migration, are prerequisites of invasiveness. These factors are presumably different in the aneuploid cells produced by Taxol, colchicine and R3, and await scrutiny.
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PMID:Polyploidisation of metastatic colon carcinoma cells by microtubule and tubulin interacting drugs: effect on proteolytic activity and invasiveness. 1537 54

To clarify the potential involvement of plasmin(ogen) cascade proteins in the cell dissociation and subsequent invasion of pancreatic cancer cells, western blot analysis, immunocytochemistry, immunohistochemistry, and in vitro invasion assay were performed in the cell lines or tissue of pancreatic cancer. The strong expression of plasmin(ogen), urokinase type plasminogen activator (uPA) and uPA receptor (uPAR), and apparently weak expression of the relevant proteins were found in the conditioned medium of dissociated (PC-1.0) and non-dissociated (PC-1) pancreatic cancer cells, respectively. Furthermore, uPA-treatment significantly induced the expression of plasmin(ogen) and uPAR in the conditioned medium of non-dissociated (PC-1) pancreatic cancer cells. Moreover, the expression of plasmin(ogen) and uPAR was stronger at the invasive front than at the center of human pancreatic cancer tissue. On the other hand, plasmin-treatment induced the expression of matrix metalloproteinase-2 (MMP-2), MMP-7 and MMP-9 in PC-1 cells. Simultaneously, plasmin- or uPA-treatments obviously induced the dissociation of cell colonies and in vitro invasiveness in PC-1 cells. The plasmin(ogen) cascade is closely involved in the invasion of pancreatic cancer cells and, especially in its early stage, cell dissociation. Targeting the plasmin(ogen) cascade may provide a new insight into molecular target therapy based on anti-invasion and anti-metastasis for pancreatic cancer.
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PMID:Analysis of the invasion-metastasis mechanism in pancreatic cancer: involvement of plasmin(ogen) cascade proteins in the invasion of pancreatic cancer cells. 1639 91