Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.4.24.17 (MMP-3)
 3,419 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The expression of messenger RNA encoding neutral metalloproteinases and the tissue inhibitor of metalloproteinases (TIMP) in human arthritic synovium was evaluated in situ, using RNA probes. Interstitial collagenase and stromelysin were expressed by synovial lining cells in patients with active rheumatoid arthritis (RA). Proteinase messenger RNA was found both in cells expressing mononuclear phagocyte antigens and in cells that were negative for the antigens. TIMP was also expressed predominantly along the synovial lining layer. In highly inflammatory RA, TIMP expression appeared less intense than that of the proteases. In osteoarthritic synovium, TIMP was expressed at easily detectable levels, whereas the expression of collagenase and stromelysin was less prominent. The balance between expression of the metalloproteinases and of the metalloproteinase inhibitor in synovium appears to be altered during inflammation. These results are consistent with the notion that synovium plays different roles in the cartilage damage of RA and of osteoarthritis.
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PMID:Expression of metalloproteinases and metalloproteinase inhibitor in human arthritic synovium. 165 8

The expression of collagenolytic activity by cells represents the rate-limiting step in the turnover of collagen during remodeling. The collagenase gene is transcriptionally activated in normal dermal or rheumatoid synovial fibroblasts by interleukin-1 beta (IL-1 beta), resulting in secretion of trypsin-activatable procollagenase measuring in the range of 2.0-5.0 units/10(6) cells/48 h in the 14C-fibril assay. The addition of interferon-gamma (IFN-gamma; 50-100 units/ml) inhibits the expression of collagenase activity by 45-80% in these cells. The IL-1 beta induction of procollagenase protein was not altered by IFN-gamma, as judged by Western blot analysis using a monoclonal antibody to collagenase and by gelatin zymography, and procollagenase mRNA was also unaltered, as assessed by Northern blot analysis. Because collagenolytic activity is also controlled by the quantity of tissue inhibitor of metalloproteinases present, its expression was examined by Western blot analysis using a polyclonal antibody to tissue inhibitor of metalloproteinases and by reverse gelatin zymography. Tissue inhibitor of metalloproteinase protein was found to be unaltered or slightly less abundant in conditioned media from cultures treated with IL-1 beta and IFN-gamma when compared with that from cultures treated with IL-1 beta alone. However, the expression of the metalloproteinase activator of procollagenase, stromelysin, was found to be significantly inhibited by the addition of IFN-gamma. Addition of purified activated stromelysin to these conditioned media completely reconstituted collagenolytic activity. These observations demonstrate in an intact system that stromelysin is a specific activator necessary for the development of collagenolytic activity. Despite stromelysin's lack of catalytic activity against collagen, its expression can serve as a control point in the regulation of collagenolysis.
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PMID:Stromelysin expression regulates collagenase activation in human fibroblasts. Dissociable control of two metalloproteinases by interferon-gamma. 166 Apr 74

Primary and passaged human synovial fibroblasts isolated from rheumatoid pannus were treated with recombinant interleukin-1 (IL-1) alpha or beta, tumor necrosis factor-alpha (TNF), or phorbol myristate acetate (PMA) to determine the effects of these stimuli on the relative expression of stromelysin, collagenase, and tissue inhibitor of metalloproteinases (TIMP). The steady-state mRNA levels for these genes and glyceraldehyde-3-phosphate dehydrogenase were determined on Northern blots. Immunoblot analyses of the conditioned media using monoclonal antibodies generated against recombinant human stromelysin, collagenase, or TIMP showed that protein levels reflected the corresponding steady-state mRNA levels. The results revealed that 1) stromelysin and collagenase were not always coordinately expressed; 2) IL-1 was more potent than TNF or PMA in the induction of stromelysin expression; 3) neither IL-1 nor TNF significantly affected TIMP expression; 4) PMA induced both metalloproteinase and TIMP expression; and 5) the combination of IL-1 plus TNF had a synergistic effect on stromelysin expression. Dose response and time course experiments demonstrated that the synergistic effect of IL-1 plus TNF occurred at saturating concentrations of each cytokine and lasted for 7 days. In summary, the ability of IL-1 and TNF to preferentially induce stromelysin and collagenase expression, versus TIMP, may define a pivotal role for these cytokines in the pathogenesis of rheumatoid arthritis.
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PMID:Discoordinate expression of stromelysin, collagenase, and tissue inhibitor of metalloproteinases-1 in rheumatoid human synovial fibroblasts. Synergistic effects of interleukin-1 and tumor necrosis factor-alpha on stromelysin expression. 169 73

To define the capacity of glucocorticoids to regulate tissue damage associated with inflammation more clearly, we have studied the effects of dexamethasone on human alveolar macrophage secretion of both a variety of metalloproteinases and also the counter-regulatory tissue inhibitor of metalloproteinases (TIMP). We found that dexamethasone selectively and coordinately inhibited expression of the following human metalloproteinases: interstitial collagenase, stromelysin, and the 92-kDa type IV collagenase, as well as TIMP. Both basal and LPS-stimulated cells exhibited similar degrees of inhibition, with greater than 50% decrease in secretion of all enzymes and TIMP observed at dexamethasone concentrations of greater than or equal to 10(-8) M in serum-containing medium. The effects of dexamethasone were mediated at a pretranslational level. In summary, our results indicate that glucocorticoids suppress the matrix-degrading phenotype that is characteristic of mature human mononuclear phagocytes, and block the effects of the most potent known signal for upregulation of metalloproteinase secretion. Similar actions in vivo would serve to limit tissue damage associated with the inflammatory response.
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PMID:Dexamethasone selectively modulates basal and lipopolysaccharide-induced metalloproteinase and tissue inhibitor of metalloproteinase production by human alveolar macrophages. 170 19

We have previously reported that polypeptide growth factors had an anti-inflammatory effect by decreasing the cytokine-enhanced expression of factor B (FB), an activator of the alternative complement pathway, in human fibroblasts. To further characterize the role of cytokines and growth factors in the inflammatory/repair continuum, we have studied the effects of interleukin-1 (IL-1) and platelet-derived growth factor (PDGF) on the expression of metalloproteinases/antiproteinases of the extracellular matrix in cultured human fibroblasts. Co-incubation of IL-1 and PDGF synergistically increased the expression of stromelysin and interstitial collagenase to 23-fold (for both proteins) over background, while PDGF decreased the IL-1-enhanced expression of FB by 82%. PDGF, but not IL-1, alone or in combination, increased the synthesis of tissue inhibitor of metalloproteinases. RNA blot analysis indicated that the changes in protein synthesis were regulated at a pretranslational level. Cycloheximide treatment indicated that the effects of PDGF on the metalloproteinases/antiproteinases were not protein-dependent, in contrast to results obtained for FB. The effect of the three dimeric forms of PDGF (AA, AB, and BB) on the synthesis of metalloproteinases and FB was also analyzed. The effects were qualitatively similar for each of the dimeric forms; however, the BB and AB isoforms had considerably greater effects than PDGF-AA. It has been reported that the PDGF receptors found in human fibroblasts have higher binding affinity for the BB and AB isoforms of the growth factor. The results presented in this paper are in accord with the possibility that differences in the biological activity of the three isoforms of PDGF are due to differences in the number or affinity of the binding sites of the target cells, rather than to different activation pathways of the receptor. Thus, PDGF increased cytokine effects on metalloproteinases, while decreasing cytokine effects or complement activator FB. The net effect of these changes may be to decrease inflammation and enhance remodeling early in repair and to enhance matrix stability later in the repair process.
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PMID:Differential regulation of the expression of proteinases/antiproteinases in fibroblasts. Effects of interleukin-1 and platelet-derived growth factor. 171 16

A specific high-titre polyclonal antiserum to recombinant human prostromelysin was raised in a sheep and shown by immunoblotting to detect latent prostromelysin, high and low Mr active forms and the C-terminal domain. This antiserum was used to demonstrate by indirect immunofluorescence that latent and active high Mr prostromelysin bind to reconstituted collagen fibrils, and to other extracellular matrix components in tissues ex vivo but that active low Mr stromelysin does not. Isolation of the C-terminal domain was carried out to demonstrate that stromelysin binding was through this domain. By use of an antiserum to the tissue inhibitor of metalloproteinases (TIMP) it was shown that TIMP is unable to bind to reconstituted collagen fibrils. TIMP, however, will bind when active high Mr stromelysin is present but not if latent prostromelysin is bound. We conclude that stromelysin has different binding specificities from those previously documented for collagenase; only active collagenase binds to reconstituted collagen fibrils. However, TIMP binds to the active forms of both stromelysin and collagenase when these are bound to the collagen fibrils. These results have important implications for the interpretation of immunolocalization data in establishing the roles of metalloproteinases and their inhibitors in vivo.
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PMID:Binding of latent and high Mr active forms of stromelysin to collagen is mediated by the C-terminal domain. 177 6

Acquisition of metastatic competence by tumor cells is frequently accompanied by increased expression of extracellular proteases capable of degrading basement membrane and extracellular matrix. However, very little is known about how the genes encoding these enzymes and their inhibitor proteins are regulated in metastatic versus nonmetastatic cells. In this report, we have compared autocrine and paracrine regulation of tissue inhibitor of metalloproteinases (TIMP), transin, and urokinase plasminogen activator (uPA) genes in genetically related nonmetastatic SP1 and metastatic A3a cell lines. Compared to SP1 cells, metastatic A3a cells showed 15-20-fold higher transin, 3-5-fold less TIMP mRNA, and comparable levels of uPA mRNA. A qualitatively similar shift in expression of these genes was rapidly (i.e., 4-8 h) induced in nonmetastatic SP1 cells following the addition of conditioned medium from A3a cells. The gene-regulating activity present in A3a conditioned medium was heat-labile, suggesting that it was protein in nature. The responsiveness of SP1 cells to the factor(s) secreted by A3a conditioned medium was inhibited by cycloheximide. Basic fibroblast growth factor mimicked the effect of the A3a conditioned medium as an inducer of transin expression in the tumor cells. Although medium conditioned by the tumor cells did not affect uPA expression, addition of epidermal growth factor to the tumor cells transiently induced expression of uPA with a biphasic response that differed in SP1 and A3a cells. Initial induction of uPA at 2-4 h was similar for both cell lines, but after 24 h of exposure to epidermal growth factor, SP1 cells showed a net reduction in uPA, whereas metastatic cells returned to the unstimulated levels.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Autocrine and paracrine regulation of tissue inhibitor of metalloproteinases, transin, and urokinase gene expression in metastatic and nonmetastatic mammary carcinoma cells. 178 52

Extracellular matrix (ECM) turnover and remodeling are initiated, at least in part, by the regulated secretion of members of a family of matrix metalloproteinases. Human and bovine trabecular mesh-work in culture secrete interstitial collagenase, both the 72- and the 92-kD forms of type IV collagenase (gelatinases) and stromelysin, and the tissue inhibitor of metalloproteinases (TIMP). These proteinases and TIMP were identified by immunoblotting western transfers from sodium dodecylsulfate-polyacrylamide gel electrophoresis (SDS-PAGE) using several specific antiprotein and antipeptide polyclonal antibodies. Gelatinase and stromelysin enzymatic activities were also analyzed by substrate SDS-PAGE, in which proteinase substrates were polymerized into the gels before electrophoresis to allow subsequent activity assays. These matrix metalloproteinases and TIMP are secreted at low basal levels into trabecular culture medium; their secretion levels are increased several-fold by treatment of the cultures with the phorbol mitogen. 12-O-tetradecanoylphorbol-13-acetate (TPA). Characteristics of the trabecular matrix metalloproteinases and TIMP are similar to those secreted by numerous other tissues, including the retinal pigment epithelium. These proteinases may serve an important role in the maintenance and regulation of the trabecular extracellular matrix and, subsequently, of the aqueous humor outflow pathway in normal and glaucomatous eyes.
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PMID:Expression of matrix metalloproteinases and inhibitor by human trabecular meshwork. 184 30

Elastin is critical to the structural integrity of a variety of connective tissues. Only a select group of enzymes has thus far been identified capable of cleaving insoluble elastin. Recently, we observed that human alveolar macrophages secrete elastase activity that is largely inhibited by the tissue inhibitor of metalloproteinases (TIMP). This finding suggested that one or more of the metalloproteinases released by alveolar macrophages has elastase activity. Accordingly, we tested pure human interstitial collagenase, stromelysin, 92-kDa type IV collagenase, and 72-kDa type IV collagenase for elastolytic activity using kappa-elastin zymography and insoluble 3H-labeled elastin. The 92- and 72-kDa type IV collagenases were found to be elastolytic in both assay systems. A recombinant preparation of 92-kDa type IV collagenase with gelatinolytic activity was also found to be elastolytic. Organomercurial activation was essential to detect elastolytic activity of the native 92- and 72-kDa type IV collagenases and enhanced the elastase activity of the recombinant 92-kDa enzyme. On a molar basis the recombinant 92-kDa type IV collagenase was approximately 30% as active as human leukocyte elastase in solubilizing 3H-labeled elastin. Exogenously added TIMP in significant molar excess abolished the elastase activity of the 92- and 72-kDa type IV collagenases. Stromelysin and interstitial collagenase showed no significant elastolytic activity, although both were catalytically active against susceptible substrates. Conditioned media from cultures of human mononuclear phagocytes containing the 92-kDa enzyme produced a distinct zone of lysis in the kappa-elastin zymograms at this molecular mass. These results definitively extend the spectrum of human proteinases with elastolytic activity to metalloproteinases and suggest the enzymatic basis for elastase activity observed with certain cell types such as human alveolar macrophages.
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PMID:Human 92- and 72-kilodalton type IV collagenases are elastases. 185 Apr 24

Extracts of human articular cartilage have been examined for the presence of metalloproteinases that degrade proteoglycans and collagen of the extracellular matrix. Two enzymes (stromelysin and acid metalloproteinase) that degrade proteoglycan are elevated at least 150% in osteoarthritis (OA), whereas the tissue inhibitor of metalloproteinases (TIMP) shows only a small increase. We postulate an imbalance of enzyme over inhibitor that leads to net matrix destruction in OA. Stromelysin is shown to have an acid pH optimum of about 5.5. At this pH it can become spontaneously active and is less susceptible to TIMP inhibition than at pH 7.5. We postulate that the chondrocytes may secrete acid into the pericellular space, leading to localized enzyme activation and proteoglycan digestion.
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PMID:Role of metalloproteinases in human osteoarthritis. 185 Dec 33


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