Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.4.24.23 (MMP)
 4,246 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Evidence presented in the accompanying article (Gibbs, D. F., T. P. Shanley, R. L. Warner, H. S. Murphy, J. Varani, and K. J. Johnson. 1999. Role of matrix metalloproteinases in models of macrophage-dependent acute lung injury: evidence for alveolar macrophage as source of proteinases. Am. J. Respir. Cell Mol. Biol. 20:1145-1154) implicates alveolar macrophage matrix metalloproteinases (MMPs) in two models of acute lung inflammation in the rat. As a prerequisite to understanding which specific MMPs might be involved in the injury and how they might function, it was necessary to know the spectrum of enzymes present. To this end, alveolar macrophages were obtained from normal rat lungs by bronchoalveolar lavage, placed in culture with and without various agonists, and assessed by a variety of techniques for MMPs. The identification process involved characterization by gelatin, beta-casein, and kappa-elastin zymography, with confirmation of identity by Western blot/immunoprecipitation. Message levels of detected MMPs were assessed by Northern blot. Rat alveolar macrophages were found to produce a low constitutive level of MMP-2 (72-kD gelatinase A) that was only modestly upregulated following stimulation with phorbol myristate acetate, bacterial lipopolysaccharide, or immunoglobulin A-containing immune complexes. Although control cells were found to produce little or no MMP-9 (92-kD gelatinase B) or MMP-12 (metalloelastase), both enzymes were markedly upregulated upon stimulation. In the same stimulated macrophages there was little activity against type I collagen (associated with MMP-13 [collagenase-3] on the basis of Western blotting), no activity suggestive of stromelysin or matrilysin, and no measurable secretion of the serine proteinases, elastase and cathepsin G. These data demonstrate the ability of rat alveolar macrophages to elaborate certain MMPs under proinflammatory conditions, consistent with their possible involvement in the progression of acute inflammation.
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PMID:Characterization of matrix metalloproteinases produced by rat alveolar macrophages. 1034 Sep 32

Membrane type 3 matrix metalloproteinase (MT3-MMP), an activator for the zymogen of MMP-2 (proMMP-2, or progelatinase A), is known to be expressed in human placenta, brain, lung and rat vascular smooth muscle cells, but information about its biochemical properties is limited. In the present study, we expressed and purified a truncated form of MT3-MMP lacking the transmembrane and intracytoplasmic domain (DeltaMT3) and characterized the enzyme biochemically. DeltaMT3 digested type III collagen into characteristic 3/4- and 1/4-fragments by cleaving the Gly781-Ile782 and Gly784-Ile785 bonds of alpha1(III) chains. Although DeltaMT3 did not have such an activity against type I collagen, it attacked the Gly4-Ile5 bond of the triple helical portion of alpha2(I) chains, leading to removal of the crosslink containing N-terminal telopeptides. By quantitative analyses of the activities of DeltaMT3 and a similar deletion mutant of MT1-MMP (DeltaMT1), DeltaMT3 was approximately fivefold more efficient at cleaving type III collagen. DeltaMT3 also digested cartilage proteoglycan, gelatin, fibronectin, vitronectin, laminin-1, alpha1-proteinase inhibitor and alpha2-macroglobulin into almost identical fragments to those given by DeltaMT1, although carboxymethylated transferrin digestion by DeltaMT3 generated some extra fragments. The activity of DeltaMT3 was inhibited by tissue inhibitor of metalloproteinases-2 (TIMP-2) and TIMP-3 in a 1 : 1 stoichiometry, but not by TIMP-1. ProMMP-2 was partially activated by DeltaMT3 to give the intermediate form. These results indicate that, like MT1-MMP, MT3-MMP exhibits proteolytic activities against a wide range of extracellular matrix molecules. However, differences in the proMMP-2 activation and tissue distribution suggest that MT3-MMP and MT1-MMP play different roles in the pathophysiological digestion of extracellular matrix.
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PMID:Characterization of a truncated recombinant form of human membrane type 3 matrix metalloproteinase. 1041 55

Normal wounds can heal by secondary intention (epidermal migration to cover a denuded surface) or by approximation of the wound edges (e.g., suturing). In healing by secondary intention, epidermis-derived MMPs are important. Keratinocyte migration begins within 3-6 hr post injury, as basal cells detach from underlying basal lamina and encounter a dermal substratum rich in type I collagen. Cell contact with type I collagen in vitro stimulates collagenase-1 expression, which is mediated by the alpha 2 beta 1 integrin, the major keratinocyte collagen-binding receptor. Collagenase-1 activity alone is necessary and sufficient for keratinocyte migration over a collagen subsurface. Stromelysins-1 and -2 are also found in the epidermis of normal acute wounds. Stromelysin-2 co-localizes with collagenase-1 and may facilitate cell migration over non-collagenous matrices of the dermis. In contrast, stromelysin-1 is expressed by keratinocytes behind the migrating front and which remain on basal lamina, i.e., the proliferative cell population. Studies with stromelysin-1-deficient mice that suggest this MMP plays a role in keratinocyte detachment from underlying basement membrane to initiate cell migration. In chronic ulcers, MMP levels are markedly elevated, in contrast to their precise temporal and spatial expression in acute wounds. Both collagenase-1 and stromelysin-1 are found in fibroblasts underlying the nonhealing epithelium, and stromelysin-1 expression is especially prominent. Two key questions underlie the use of MMP inhibitors and wound healing: (1) will these agents impair normal reepithelialization in wounds that heal by secondary intention; and (2) can MMP inhibitors be effective therapy for chronic ulcers? The answer to neither is known. Batimastat and marimastat appear not to interfere with normal wound healing, but only in sutured surgical wounds, a situation in which MMP expression has practically no role. We also show the first example of an in vivo immune response, contact hypersensitivity, which is dependent upon MMP activity. Using gene-deficient mice, we demonstrate that stromylysin-1 (MMP-3) is required for sensitization, whereas gelatinase B (MMP-9) is required for timely resolution of the reaction to antigenic challenge.
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PMID:Role of matrix metalloproteinases and their inhibition in cutaneous wound healing and allergic contact hypersensitivity. 1041 17

Cancer mortality usually results from the tumor invading the local environment and metastasizing to vital organs, e.g. liver, lung, and brain. Degradation of the extracellular matrix is, therefore, the sine qua non of tumor cell invasion. this degradation is mediated mainly by MMPs, and thus, inhibition of MMP synthesis is a target for anticancer agents. Tumor cells must traverse both the basement membrane (type IV collagen) and the interstitial stroma (type I collagen). Therefore, we used scanning electron microscopy to examine the invasive behavior of several aggressive tumor cell lines, A2058 melanoma cells, and SCC and FaDu squamous cell carcinomas through these matrices; and we monitored the ability of all-trans retinoic acid and several RAR-specific ligands to block invasion. We demonstrate that several retinoids, which are specific RAR alpha, beta, or gamma agonists/antagonists, selectively inhibited MMP synthesis in the three tumor cell lines. However, there was not a common pattern of MMP inhibition by a particular retinoid. For instance, a RAR alpha antagonist suppressed MMP-1 and MMP-2 synthesis in the melanoma cell line, but not in the FaDu or SCC-25 cells. On the other hand, synthesis of MMP-1 and MMP-9 by the FaDu cells was affected hardly at all, while a RAR gamma antagonist reduced the levels of MMP-2. Only all-trans retinoic acid reduced MMP-1 synthesis in these cells. We postulate that the differences may be related to a differential pattern of RAR expression in each of these cells, and that the RARs expressed by each cell line may not be targets of these RAR specific compounds. All-trans retinoic acid is a pan ligand, binding to all three RARs and, therefore, may modulate gene expression more generally. We conclude that the power of these new ligands lies in their specificity, which can be directed towards modulating expression of certain RARs and, thus, of certain MMPs. By blocking MMP synthesis, retinoids may be effective in cancer therapy by decreasing tumor invasiveness.
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PMID:Retinoid-mediated suppression of tumor invasion and matrix metalloproteinase synthesis. 1041 49

Along with degradation of type IV collagen in basement membrane, destruction of the stromal collagens, types I and III, is an essential step in the invasive/metastatic behavior of tumor cells, and it is mediated, at least in part, by interstitial collagenase 1 (matrix metalloproteinase 1 (MMP-1)). Because A2058 melanoma cells produce substantial quantities of MMP-1, we used these cells as models for studying invasion of type I collagen. With a sensitive and quantitative in vitro invasion assay, we monitored the ability of these cells to invade a matrix of type I collagen and the ability of a serine proteinase inhibitor and all-trans-retinoic acid to block invasion. Although these cells produce copious amounts of MMP-1, they do not invade collagen unless they are co-cultured with fibroblasts or with conditioned medium derived from fibroblasts. Our studies indicate that a proteolytic cascade that depends on stromal/tumor cell interactions facilitates the ability of A2058 melanoma cells to invade a matrix of type I collagen. This cascade activates latent MMP-1 and involves both serine proteinases and MMPs, particularly stromelysin 1 (MMP-3). All-trans-retinoic acid (10(-6) M) suppresses the invasion of tumor cells by several mechanisms that include suppression of MMP synthesis and an increase in levels of tissue inhibitor of metalloproteinases 1 and 2. We conclude that invasion of stromal collagen by A2058 melanoma cells is mediated by a novel host/tumor cell interaction in which a proteolytic cascade culminates in the activation of pro-MMP-1 and tumor cell invasion.
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PMID:A novel host/tumor cell interaction activates matrix metalloproteinase 1 and mediates invasion through type I collagen. 1046 64

An immunoassay for cross-linked N-telopeptides of type I collagen (NTx) in urine or serum has proven to give a sensitive index of osteoclast-mediated bone resorption. We show that recombinant human cathepsin K is highly active in releasing the NTx neoepitope in 100% yield from bone type I collagen. Cathepsins S, L, and B were also active but at 57%, 36%, and 27% of the yield of K, respectively. The matrix metalloproteinases that were tested, stromelysin, collagenase 3, or matrilysin, did not produce any immunoreactivity. Cathepsin K also acted on demineralized bone matrix, releasing NTx epitope and completely dissolving the bone particles in 24-48 h. Proteolytic cleavage of a G-L peptide bond in the alpha2(I)N-telopeptide was shown to be required for recognition by monoclonal antibody 1H11. Peptide analysis identified bonds in the N-telopeptide and helical cross-linking domains adjacent to the cross-linking residues at which cathepsin K cleaved in bone collagen. The sites were consistent with the known substrate specificity of cathepsin K, which prefers a hydrophobic residue or proline in the critical P2 position. The NTx peptides generated by cathepsin K were of low molecular weight, in the range previously found in human urine. Because cathepsin K appears to be essential for the normal resorption of mineralized bone matrix by osteoclasts, these findings help explain the specificity and responsiveness of NTx as a marker of osteoclastic bone resorption in vivo.
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PMID:Proteolysis of human bone collagen by cathepsin K: characterization of the cleavage sites generating by cross-linked N-telopeptide neoepitope. 1070 96

Membrane type 1 matrix metalloproteinase (MT1-MMP) is a membrane-bound proteinase and a cell-surface receptor and activator of gelatinase A in normal and neoplastic cells. We have expressed and purified a soluble deletion mutant of MT1-MMP lacking the transmembrane and cytoplasmic domains and an inactive mutant of the soluble MT1-MMP, where the active-site glutamic acid(240) was substituted by alanine (E240A). A baculovirus transfer vector coding for amino acids 21-539 of MT1-MMP (DeltaTM) and a similar vector coding for the mutation (E240ADeltaTM) were constructed for expression in insect cells. Both DeltaTM and E240ADeltaTM were secreted to the culture medium of infected High Five insect cells. They were then purified by cation-exchange followed by gel-filtration chromatography. DeltaTM was able to cleave denatured type I collagen and fibronectin and activate MMP-2/gelatinase-A, while E240ADeltaTM had only low proteolytic activity against denatured collagen I. The current expression and purification protocol should prove useful for the production of large amounts of enzymatically active soluble MT1-MMP.
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PMID:Expression and purification of soluble and inactive mutant forms of membrane type 1 matrix metalloproteinase. 1083 92

During tissue-invasive events, migrating cells penetrate type I collagen-rich interstitial tissues by mobilizing undefined proteolytic enzymes. To screen for members of the matrix metalloproteinase (MMP) family that mediate collagen-invasive activity, an in vitro model system was developed wherein MDCK cells were stably transfected to overexpress each of ten different MMPs that have been linked to matrix remodeling states. MDCK cells were then stimulated with scatter factor/hepatocyte growth factor (SF/HGF) to initiate invasion and tubulogenesis atop either type I collagen or interstitial stroma to determine the ability of MMPs to accelerate, modify, or disrupt morphogenic responses. Neither secreted collagenases (MMP-1 and MMP-13), gelatinases (gelatinase A or B), stromelysins (MMP-3 and MMP-11), or matrilysin (MMP-7) affected SF/HGF-induced responses. By contrast, the membrane-anchored metalloproteinases, membrane-type 1 MMP, membrane-type 2 MMP, and membrane-type 3 MMP (MT1-, MT2-, and MT3-MMP) each modified the morphogenic program. Of the three MT-MMPs tested, only MT1-MMP and MT2-MMP were able to directly confer invasion-incompetent cells with the ability to penetrate type I collagen matrices. MT-MMP-dependent invasion proceeded independently of proMMP-2 activation, but required the enzymes to be membrane-anchored to the cell surface. These findings demonstrate that MT-MMP-expressing cells can penetrate and remodel type I collagen-rich tissues by using membrane-anchored metalloproteinases as pericellular collagenases.
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PMID:Regulation of cell invasion and morphogenesis in a three-dimensional type I collagen matrix by membrane-type matrix metalloproteinases 1, 2, and 3. 1085 Oct 27

Tumor cell adhesion and proteolysis of the extracellular matrix proteins surrounding the cells are tightly linked processes in tumor invasion. In this study, we sought to identify components of the cell surface of a vertical growth phase melanoma cell line, WM1341D, that mediate invasive cellular behavior. We determined by antisense inhibition that melanoma chondroitin sulfate proteoglycan (MCSP) and membrane-type 3 matrix metalloproteinase (MT3-MMP) expressed on WM1341D are required for invasion of type I collagen and degradation of type I gelatin. MT3-MMP co-immunoprecipitated with MCSP in WM1341D melanoma cells cultured on type I collagen or laminin. The association between MT3-MMP and MCSP was largely disrupted by removing chondroitin sulfate glycosaminoglycan (CS) from the cell surface, suggesting CS could mediate the association between the two cell surface core proteins. Recombinant MT3-MMP and MT3-MMP from whole cell lysates of WM1341D cells were specifically eluted from CS- conjugated affinity columns. The results indicate that MT3-MMP possesses the potential to promote melanoma invasion and proteolysis and that the formation of a complex between MT3-MMP and MCSP may be a crucial step in activating these processes.
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PMID:Melanoma chondroitin sulfate proteoglycan regulates matrix metalloproteinase-dependent human melanoma invasion into type I collagen. 1127 6

Type I collagen stimulation of pro-matrix metalloproteinase (pro-MMP)-2 activation by ovarian cancer cells involves beta(1) integrin receptor clustering; however, the specific cellular and biochemical events that accompany MMP processing are not well characterized. Collagenolysis is not required for stimulation of pro-MMP-2 activation, and denatured collagen does not elicit an MMP-2 activation response. Similarly, DOV13 cells bind to intact collagen utilizing both alpha(2)beta(1) and alpha(3)beta(1) integrins but interact poorly with collagenase-treated or thermally denatured collagen. Antibody-induced clustering of alpha(3)beta(1) strongly promotes activation of pro-MMP-2, whereas alpha(2)beta(1) integrin clustering has only marginal effects. Membrane-type 1 (MT1)-MMP is present on the DOV13 cell surface as both an active 55-kDa TIMP-2-binding species and a stable catalytically inactive 43-kDa form. Integrin clustering stimulates cell surface expression of MT1-MMP and co-localization of the proteinase to aggregated integrin complexes. Furthermore, cell surface proteolysis of the 55-kDa MT1-MMP species occurs in the absence of active MMP-2, suggesting MT1-MMP autolysis. Cellular invasion of type I collagen matrices requires collagenase activity, is blocked by tissue inhibitor of metalloproteinases-2 (TIMP-2) and collagenase-resistant collagen, is unaffected by TIMP-1, and is accompanied by pro-MMP-2 activation. Together, these data indicate that integrin stimulation of MT1-MMP activity is a rate-limiting step for type I collagen invasion and provide a mechanism by which this activity can be down-regulated following collagen clearance.
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PMID:Functional interplay between type I collagen and cell surface matrix metalloproteinase activity. 1133 Dec 72


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