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

Fibroblast growth factor-2 (FGF-2) is an established mediator of smooth muscle cell (SMC) proliferation after vascular injury. However, the influence of FGF-2 on collagen fiber remodeling, which may be a prerequisite for vascular SMC accumulation, is not well understood. We determined that FGF-2 almost completely abrogated the formation of immunodetectable type I collagen fibers in the extracellular matrix of cultured human vascular SMCs. This was associated with reduced expression of pro alpha-chains for types I and III collagen, as assessed by Western blot analysis, and a corresponding reduction in collagen synthesis. Densitometry of Northern blots indicated a potent reduction of mRNA encoding pro alpha-chains for types I and III collagen and a minor reduction in mRNA for pro alpha-chains for type V collagen. Interstitial collagenase (MMP-1), which is required for degradation of collagen types I and III, was not expressed by SMCs under basal culture conditions, but expression was induced by FGF-2, with a potent, dose-dependent increase in MMP-1 protein in conditioned medium. Metalloproteinase inhibitors TIMP-1, TIMP-2, and TIMP-3 were expressed by unstimulated SMCs and were differentially regulated by FGF-2. TIMP-1 expression increased modestly, TIMP-2 expression was repressed, and TIMP-3 was relatively unaffected. The net effect on substrate degradation, as assessed by zymography of conditioned media, was induction of MMP-1 lytic activity by FGF-2, with no effect on the activity of MMP-2, MMP-3, or MMP-9. These data indicate that stimulation of human SMCs with FGF-2 establishes a phenotype in which collagen fiber production is repressed and the capacity for fiber degradation activated. This coordinated response may be critical for SMC accumulation during vascular remodeling as well as atherosclerotic plaque destabilization.
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PMID:Coordinated effects of fibroblast growth factor-2 on expression of fibrillar collagens, matrix metalloproteinases, and tissue inhibitors of matrix metalloproteinases by human vascular smooth muscle cells. Evidence for repressed collagen production and activated degradative capacity. 910 65

Phospholipase C (PLC) is a putative virulence factor of several pathogenic bacteria. We studied if exogenous PLC would perturb epithelial behavior in infected tissues. Gelatin and casein zymography of cell culture medium indicated that the broad-spectrum PLC of Bacillus cereus induced matrix metalloproteinase (MMP) production in epithelial cells of human skin (NHEK), human gingiva (HGE), and porcine periodontal ligament (PLE). In all three cell types, the strongest increase (ninefold) at 0.1 U/ml was seen in the MMP-9 (92-kDa gelatinase) activity, and the effect was dose dependent in the range of 0.1 to 1.0 U/ml. A relatively weaker increase (twofold) in MMP-2 (72-kDa gelatinase) was also observed in each cell type. PLC induction of MMP-3 (48-kDa stromelysin) was also seen in NHEK and HGE on gelatin and more sensitively for PLE by casein zymography (fivefold). Total gelatinolytic activity as measured by degradation of 14C-labeled denatured type I collagen increased by about 18-fold (NHEK), 12-fold (HGE), and 14-fold (PLE). Northern analysis showed a clear increase in the MMP-9, and a minor increase in MMP-3 mRNA levels but no significant increase in MMP-2 mRNA levels. Further studies with PLE revealed that MMP-9 induction by PLC progressively increased with the length of cell culture time in the absence of serum. PLC induction of MMPs was polar, with MMP-9 and MMP-3 secreted primarily in the apical direction and MMP-2 secreted mainly in the basal direction. The PLC effect was blocked by neomycin, an inhibitor of the phosphoinositol signal pathway. No significant effects were observed in MMP expression with the calcium ionophore A23187 or phospholipase A2. Morphologically, PLC treatment resulted in reduced contacts between the cultured cells and loss of the cell surface microvilli. These results suggest that PLC secreted by bacterial pathogens may disrupt epithelium of infected tissue and increase the subepithelial tissue destruction through induction of MMPs.
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PMID:Bacterial phospholipase C upregulates matrix metalloproteinase expression by cultured epithelial cells. 939 78

Interleukin-1 (IL-1) greatly induces osteoclast formation and stimulates bone resorption of mouse calvaria in culture. In the presence of soluble IL-6 receptor (sIL-6R), IL-6 similarly induces osteoclast formation, but the potency of IL-6 in inducing bone resorption in organ culture is weaker than that of IL-1. To study the differences in bone-resorbing activity between IL-1 and IL-6, we examined the effects of the two cytokines on the induction of matrix metalloproteinases (MMPs). In mouse calvarial cultures, IL-1 markedly enhanced the messenger RNA (mRNA) expression of MMP-13 (collagenase 3), MMP-2 (gelatinase A), MMP-9 (gelatinase B), and MMP-3 (stromelysin 1), which associated with increases in bone matrix degradation. A hydroxamate inhibitor of MMPs significantly suppressed bone-resorbing activity induced by IL-1. Gelatin zymography showed that both pro- and active-forms of MMP-2 and MMP-9 were detected in the conditioned medium collected from calvarial cultures, and IL-1 markedly stimulated both pro- and active-forms of the two gelatinases. IL-6 with sIL-6R also stimulated mRNA expression and biological activities of these MMPs, but the potency was much weaker than that of IL-1. Conditioned medium collected from IL-1-treated calvariae degraded native type I collagen, but 3/4- and 1/4-length collagen fragments were not detected, suggesting that both collagenases and gelatinases synergistically degraded type I collagen into smaller fragments. In mouse osteoblastic cells, the expression ofMMP-2, MMP-3, and MMP-13 mRNAs could be detected, and they were markedly enhanced by IL-1alpha on days 2 and 5. IL-6 with sIL-6R also induced expression of MMP-13 and MMP-2 mRNAs on day 2, but the expression was rather transient. These results demonstrate that the potency of induction of MMPs by IL-1 and IL-6 is closely linked to the respective bone-resorbing activity, suggesting that MMP-dependent degradation of bone matrix plays a key role in bone resorption induced by these cytokines.
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PMID:Regulation of matrix metalloproteinases (MMP-2, -3, -9, and -13) by interleukin-1 and interleukin-6 in mouse calvaria: association of MMP induction with bone resorption. 949 70

Normal as well as neoplastic cells traverse extracellular matrix barriers by mobilizing proteolytic enzymes in response to epidermal growth factor (EGF)-EGF receptor (EGFR) or hepatocyte growth factor/scatter factor (SF)-c-Met interactions. The plasminogen activator-plasminogen axis has been proposed to play a key role during cell invasion, but the normal development of plasminogen activator- as well as that of plasminogen-deficient mice supports the existence of alternate proteolytic systems that permit cells to traverse extracellular matrix barriers. To characterize the role that matrix-degrading proteinases play in EGF- or SF-stimulated invasion, a human squamous carcinoma cell line (UM-SCC-1) was triggered atop the matrices of type I collagen or human dermal explants in a three-dimensional culture system. During EGF- or SF-induced invasion, UM-SCC-1 cells expressed urokinase-type plasminogen activator (uPA) and uPA receptor as well as the matrix metalloproteinases (MMPs), membrane-type MMP-1, collagenase 1, stromelysin 1, and gelatinase B. Despite the presence of a positive correlation between uPA receptor-uPA expression and growth factor-stimulated invasion, UM-SCC-1 invasion was not affected by inhibitors directed against the plasminogen activator-plasminogen axis. In contrast, both recombinant and synthetic MMP inhibitors completely suppressed invasion by either EGF- or SF-stimulated cells without affecting either proteinase expression or cell motility across collagen-coated surfaces. These data demonstrate that MMPs, but not the plasminogen activator-plasmin system, can directly regulate the ability of either EGF- or SF-stimulated tumor cells to invade interstitial matrix barriers.
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PMID:Role of the plasminogen activator and matrix metalloproteinase systems in epidermal growth factor- and scatter factor-stimulated invasion of carcinoma cells. 982 36

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

Previous studies have shown a correlation between the production of certain matrix metalloproteinases (MMPs), especially the gelatinases, by malignant tumors and the progression of these cancers as they invade and metastasize through the extracellular matrix and basement membranes. However, very few of these studies examined this relationship in human oral cancer in vivo, and none addressed the issue of how combinations of the MMPs may further enhance tumor progression. To determine which MMPs are produced in vivo by human oral cancers, we used specific anti-human-MMP antibodies and immunocytochemistry (ICC) methods to examine oral cancer tissue specimens from 20 surgery patients. The ICC data indicated that 72-kDa (72K-GL) and 92-kDa gelatinases (92K-GL) were produced in vivo by discreet clusters of tumor cells and by stromal fibroblasts, vascular endothelial cells (72K-GL), and PMNs (92K-GL). Some stromal fibroblasts near the tumors also appeared to produce fibroblast-type collagenase (FIB-CL), a finding confirmed by Western blot analysis of media conditioned by oral tumor explant cultures. ICC results indicated that 5 of the 20 tumors coincidentally produced all three MMPs. To examine how the two gelatinases and FIB-CL may interact in vitro to degrade fibrillar type I collagen, a major structural component of the extracellular matrix, we used a modified FIB-CL activity assay. Combinations of the gelatinases and FIB-CL were incubated with a 3H-collagen substrate, with the results compared with the combination of stromelysin-1 (SL-1, a superactivator of FIB-CL) and FIB-CL. 92K-GL caused a nine-fold increase in collagenase activity, equivalent to SL-1, while 72K-GL produced a four-fold increase. These results indicate that human oral cancers produce 92K-GL, 72K-GL, and FIB-CL in vivo and that the gelatinases and FIB-CL cooperate to enhance collagen degradation greatly in vitro.
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PMID:92K-GL (MMP-9) and 72K-GL (MMP-2) are produced in vivo by human oral squamous cell carcinomas and can enhance FIB-CL (MMP-1) activity in vitro. 1040 63

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

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

The matrix metalloproteinase (MMP) family has been implicated in the process of a variety of diseases such as arthritis, atherosclerosis, and tumor cell metastasis. To study the mechanisms of MMP action on collagenous substrates, we have constructed homotrimeric triple-helical peptide (THP) models of the collagenase cleavage sites in types I and II collagen. The THPs incorporate either the alpha1(I)772-786 or the alpha1(II)772-783 sequence. The alpha1(I)772-786 and alpha1(II)772-783 THPs were hydrolyzed by MMP-1 at the Gly-Ile and Gly-Leu bonds, respectively, analogous to the bonds cleaved in corresponding native collagens. Thus, the THPs contained all necessary information to direct MMP-1 binding and proteolysis. Subsequent investigations using the alpha1(I)772-786 THP showed hydrolysis by MMP-2, MMP-13, and a COOH-terminal domain-deleted MMP-1 (MMP-1(Delta(243-450))) but not by MMP-3 or a COOH-terminal domain-deleted MMP-3 (MMP-3(Delta(248-460))). Kinetic analyses showed a k(cat)/K(m) value of 1,808 s(-1) m(-1) for MMP-1 hydrolysis of alpha1(I)772-786 THP, approximately 10-fold lower than for type I collagen. The effect is caused primarily by relative K(m) values. MMP-2 and MMP-13 cleaved the THP more rapidly than MMP-1, but MMP-2 cleavage occurred at distinct multiple sites. Comparison of MMP-1 and MMP-1(Delta(243-450)) hydrolysis of alpha1(I)772-786 THP showed that both can cleave a triple-helical substrate with a slightly higher K(m) value for MMP-1(Delta(243-450)). We propose that the COOH-terminal domain of MMPs is necessary for orienting whole, native collagen molecules but may not be necessary for binding to and cleaving a THP. This proposal is consistent with the large distance between the MMP-1 catalytic and COOH-terminal domains observed by three-dimensional structural analysis and supports previous suggestions that the features of the catalytic domain contribute significantly toward enzyme specificity.
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PMID:Hydrolysis of triple-helical collagen peptide models by matrix metalloproteinases. 1078 34


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