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)

Matrix metalloproteinases (MMPs) and tissue inhibitors of metalloproteinases (TIMPs) play a significant role in regulating angiogenesis, the process of new blood vessel formation. Interstitial collagenase (MMP-1), 72 kDa gelatinase A/type IV collagenase (MMP-2), and 92 kDa gelatinase B/type IV collagenase (MMP-9) dissolve extracellular matrix (ECM) and may initiate and promote angiogenesis. TIMP-1, TIMP-2, TIMP-3, and possibly, TIMP-4 inhibit neovascularization. A new paradigm is emerging that matrilysin (MMP-7), MMP-9, and metalloelastase (MMP-12) may block angiogenesis by converting plasminogen to angiostatin, which is one of the most potent angiogenesis antagonists. MMPs and TIMPs play a complex role in regulating angiogenesis. An understanding of the biochemical and cellular pathways and mechanisms of angiogenesis will provide important information to allow the control of angiogenesis, e.g. the stimulation of angiogenesis for coronary collateral circulation formation; while the inhibition for treating arthritis and cancer.
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PMID:Complex role of matrix metalloproteinases in angiogenesis. 979 30

Membrane-type 3 matrix metalloproteinase (MT3-MMP) is a novel MT-MMP which has a transmembrane domain at the C terminus, and mediates activation of pro-gelatinase A, just as does MT1-MMP. Previously, we reported that MT1-MMP was expressed on microglial cells only in the white matter [Yamada T, Yoshiyama Y, Sato H, Seiki M, Shinagawa A, Takahashi M (1995) Acta Neuropathol 90:421-424]. In the present study of both non-neurological and Alzheimer brain tissues, we examined the localization of MT3-MMP by immunohistochemistry. Anti-MT3-MMP antibodies gave positive staining of microglial cells in all brain tissues. Positively stained microglia were found not only in the white matter but also in the gray matter. Reverse transcriptase-polymerase chain reaction for MT3-MMP mRNA showed the same amount of expression in gray and white matters, while that for gelatinase A and MT1-MMP mRNA expressed much higher in the white matter than in the gray matter. These results suggest that MT3-MMP may play a role on microglial cells, although its role may be different from MT1-MMP in the brain.
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PMID:Expression of the membrane-type 3 matrix metalloproteinase (MT3-MMP) in human brain tissues. 979 98

In situ gelatin zymography is a technique, which utilises a gelatin-based emulsion overlay to detect and, more importantly, localise the gelatinase activity in underlying tissue. Gelatinase A [matrix metalloproteinase-2 (MMP-2)] and gelatinase B [matrix metalloproteinase-9 (MMP-9)] are present in equine hoof homogenates and supernatants from cultured hoof explants by SDS-PAGE gelatin zymography, and it has been assumed that the enzymes are derived solely from matrix and epithelia and not from other sources such as leucocytes. Using in situ zymography, gelatinases are shown to be localised within the equine epidermal hoof lamellae and, more specifically, are apparently produced by epidermal basal and/or parabasal cells. The pattern of expression correlates with that expected based on the progression of pathological changes observed during the onset of laminitis, thus providing further evidence that laminitis pathology probably arises as a result of inadequate local MMP regulation.
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PMID:Localisation of gelatinase activity in epidermal hoof lamellae by in situ zymography. 982 33

Matrix metalloproteinase-2 (MMP-2, gelatinase A) is involved in the inflammatory and sclerotic events of glomerular diseases. Newly identified membrane-type matrix metalloproteinases (MT-MMP) have been shown to activate specifically proMMP-2. To date, several types of MT-MMP have been cloned; however, their expressions in glomerular diseases have not been evaluated. To investigate the role of MT-MMP in glomerular diseases, the glomerular gene expression and enzymatic activity of MT-MMP were examined during the time course of nephritis induced in rats by anti-Thy1.1 antibody injection. Both MT1-MMP and MMP-2 mRNA expression increased prominently 5 and 10 d after anti-Thy1.1 antibody injection and decreased thereafter, as assayed by semiquantitative reverse transcription-PCR. In contrast, there were no remarkable changes in the gene expression of MT2-MMP between normal and diseased tissue, and that of MT3-MMP was not detected in isolated glomeruli by reverse transcription-PCR analysis. The activation of proMMP-2 as analyzed by gelatin zymography correlated with the glomerular MT1-MMP gene expression, suggesting that proMMP-2 was activated by MT1-MMP. Protein and mRNA expression of fibronectin, one of the major mesangial matrix proteins and substrate of MMP-2, were also synchronized with MT1-MMP and MMP-2 expression. In situ hybridization revealed intense MT1-MMP mRNA expression in the proliferating mesangial cells. Interestingly, MT1-MMP gene expression exhibited a similar distribution as alpha-smooth muscle actin expression, which was closely associated with mesangial phenotypic change. These results suggest that among the newly identified MT-MMP, MT1-MMP may play the central role in activation of proMMP-2. Furthermore, the enhancement of MT1-MMP and MMP-2 expression associated with mesangial phenotypic change may contribute to the development of anti-Thy1.1 antibody-induced glomerulonephritis and remodeling of extracellular matrices.
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PMID:Enhanced expression of membrane type-1 matrix metalloproteinase in mesangial proliferative glomerulonephritis. 984 80

Activation of the matrix metalloproteinase 2 (MMP-2) has been shown to play a major role in the proteolysis of extracellular matrix (ECM) associated with tumor invasion. Although the precise mechanism of this activation remains elusive, levels of the membrane type 1-MMP (MT1-MMP) at the cell surface and of the tissue inhibitor of MMP-2 (TIMP-2) appear to be two important determinants. Induction of MMP-2 activation in cells cultivated on collagen type I gels indicated that the ECM is important in the regulation of this process. In this study, we show that SPARC/osteonectin, a small ECM-associated matricellular glycoprotein, can induce MMP-2 activation in two invasive breast cancer cell lines (MDA-MB-231 and BT549) but not in a noninvasive counterpart (MCF-7), which lacks MT1-MMP. Using a set of peptides from different regions of SPARC, we found that peptide 1.1 (corresponding to the NH2-terminal region of the protein) contained the activity that induced MMP-2 activation. Despite the requirement for MT1-MMP, seen in MCF-7 cells transfected with MT1-MMP, the activation of MMP-2 by SPARC peptide 1.1 was not associated with increased steady-state levels of MT1-MMP mRNA or protein in either MT1-MMP-transfected MCF-7 cells or constitutively expressing MDA-MB-231 and BT549 cells. We did, however, detect decreased levels of TIMP-2 protein in the media of cells incubated with peptide 1.1 or recombinant SPARC; thus, the induction of MMP-2 activation by SPARC might be due in part to a diminution of TIMP-2 protein. We conclude that SPARC, and specifically its NH2-terminal domain, regulates the activation of MMP-2 at the cell surface and is therefore likely to contribute to the proteolytic pathways associated with tumor invasion.
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PMID:SPARC/osteonectin induces matrix metalloproteinase 2 activation in human breast cancer cell lines. 985 90

Membrane-type matrix metalloproteinases (MT-MMP) activate the zymogen form of MMP-2/Gelatinase A on cell surfaces and are expressed in invasive tumors. We sought to identify and characterize MT-MMP in a non-malignant cell type that undergoes a physiologic and reversible invasive phenotype during angiogenesis. Human dermal microvascular endothelial cells (HDMEC) were isolated from neonatal tissue and purified by anti-CD31 (PECAM) affinity beads. MT-MMP-1 and -3 transcripts were amplified by reverse transcriptase-polymerase chain reaction and northern blots showed a single 4.5 kB mRNA for MT-MMP-1 that was modulated by angiogenic factors and phorbol ester. Immunoblotting of reduced cellular extracts with different MT-MMP-1 antibodies showed the presence of the 63-65 kDa and 57-60 kDa forms, as well as additional forms at lower molecular weights. HDMEC membranes extracted with Triton X114 were incubated with gelatin-sepharose purified MMP-2 and MMP-9 to show activation of proenzymes. Pre-incubation of HDMEC with anti-MT-MMP-1 antibodies decreased proMMP-2 conversion activity only. The movement of HDMEC and the formation of tubule-like structures in three-dimensional collagen gels was markedly delayed by preincubation with the same anti-MT-MMP-1 antibodies. These results demonstrate the presence of MT-MMP in cutaneous microvascular cells in vitro. Modulation of these cell surface proteinases by angiogenic factors, demonstration of multiple processed forms, and specific attenuation of HDMEC morphogenetic patterns in three-dimensional collagen gels implicate their potential roles in the formation of new blood vessels in the skin.
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PMID:Membrane-type matrix metalloproteinases in human dermal microvascular endothelial cells: expression and morphogenetic correlation. 985 32

Collagenase-3 (MMP-13) is a matrix metalloproteinase recently identified on the basis of differential expression in normal breast tissues and in breast carcinoma. To date, collagenase-3 expression has been reported only in breast carcinomas and in articular cartilage of arthritic patients; the presence and possible implication of this enzyme in the progression of other malignant tumours are unknown. In this study collagenase-3 mRNA expression has been analysed by northern blot in a series of 35 matched squamous cell carcinomas of the larynx and the corresponding adjacent non-neoplastic tissues. In addition, mRNA expression of membrane type 1-matrix metalloproteinase (MT1-MMP) and gelatinase A, two matrix metalloproteinases which have the ability to activate collagenase-3 in vitro, was also examined in the same cases. No collagenase-3 expression was detected in any of the 35 normal mucosae, but collagenase-3 mRNA was observed in 20 of the 35 carcinomas (57 per cent). Western blot analysis revealed the presence of collagenase-3 protein in those carcinomas with high levels of mRNA expression, whereas no protein was detected in the carcinomas with negative mRNA expression, or in any of the normal tissues. The protein was localized predominantly in tumour epithelial cells. Collagenase-3 expression correlated significantly with better histological differentiation of the tumours (p = 0.026), as well as with advanced local invasion (p = 0.026). Collagenase-3 upregulation was also significantly associated with MT1-MMP and gelatinase A overexpression. These findings suggest that collagenase-3 expression may contribute to the progression of a significant subset of squamous cell carcinomas of the larynx and that its coordinate overexpression with MT1-MMP and gelatinase A may have a cooperative effect in the progression of the tumours.
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PMID:Collagenase-3 expression is associated with advanced local invasion in human squamous cell carcinomas of the larynx. 992 29

The purpose of this study was to investigate the association among matrix metalloproteinases (gelatinases A and B, stromelysin-3 (ST3) and matrilysin) mRNAs expressed in primary breast carcinomas and standard prognostic parameters and clinical outcome. mRNA levels were determined by Northern analysis in samples of 81 breast cancer patients (median follow-up, 40 months) and 27 samples of uninvolved adjacent breast tissue. Proteases were expressed by the majority of the tumors and normal breast tissues examined. ST3, gelatinase A and matrilysin mRNAs were more often expressed at high levels in carcinomatous than in normal breast tissues. Differences in the distribution of gelatinase B mRNA were not found. However, paired normal tissues generally produced weaker signals when compared to matched tumor samples. Univariate analysis showed no significant association of gelatinase A and matrilysin mRNAs with the classical prognostic markers (age, menopausal status, stage, size, nodal status, vascular infiltrate, necrosis, steroid receptors, metastasis and survival). Overexpression of ST3 was more frequently found in tumors of post-menopausal women (P < 0.022). Elevated expression of gel B mRNA was associated with the presence of vascular infiltrate (P < 0.026), necrosis (P < 0.039), PR negative tumors (P < 0.014) and inversely correlated to the number of survivors (P < 0.021). Multivariate analysis including 68 patients for whom all information was available indicated that neither stromelysin correlated significantly with pathological, clinical or biochemical features. High levels of gelatinase A and B mRNAs were inversely associated with the number of survivors. Our findings suggest that measurements of gelatinase A and B mRNAs expression in breast carcinoma may help to identify patients with an aggressive form of the disease.
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PMID:Expression of gelatinases A and B, stromelysin-3 and matrilysin genes in breast carcinomas: clinico-pathological correlations. 993 4

Tissue inhibitor of metalloproteinases-2 (TIMP-2) is supposed to play a regulatory role in the cell-mediated activation of progelatinase A. To investigate the mechanism of the regulation, we prepared and characterized a chemically modified TIMP-2, and examined its effects on the activation of progelatinase A. We found that treatment of TIMP-2 with cyanate ion led to loss of inhibitory activity toward matrilysin or gelatinase A. Structural and functional analyses of the modified TIMP-2 showed that carbamylation of the alpha-amino group of the NH2-terminal Cys1 of TIMP-2 led to complete loss of the inhibitory activity. When the reactive-site modified TIMP-2 was added to culture medium of concanavalin A-stimulated HT1080 cells, the conversion of endogenous progelatinase A to the intermediate form was partially inhibited, whereas that of the intermediate form to the mature one was strongly inhibited. The reactive site-modified TIMP-2 also prevented an accumulation of active gelatinase A on the cell surface. We speculate that occupation of the hemopexin-like domain of gelatinase A by the reactive site-modified TIMP-2 makes it unable for gelatinase A to be retained on the cell surface, thus preventing the autocatalytic conversion of the intermediate form of gelatinase A to its mature form.
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PMID:Reactive site-modified tissue inhibitor of metalloproteinases-2 inhibits the cell-mediated activation of progelatinase A. 1018 41

Thrombin has been shown previously to activate gelatinase A in human umbilical vein endothelial cells. The activation is thought to be mediated by membrane-type 1 matrix metalloproteinase (MT1-MMP) on the cell surface, which generates the 62-kd intermediate and the 59-kd fully active forms. We used microvascular endothelial cells derived from human neonatal foreskin to investigate the mechanism of gelatinase A activation by thrombin. Gelatinase A was measured using zymography. Whereas activation by PMA generated both the 62-kd intermediate and the 59-kd fully active forms of gelatinase A after 24 hours, activation by thrombin produced only the 59-kd species rapidly (within 2 hours). Four findings indicate that MT1-MMP was not involved in thrombin-induced activation: (1) there was no up-regulation of MT1-MMP after 2 hours stimulation by thrombin, even though there was activation of gelatinase A; (2) the 62-kd intermediate species was never detected in response to thrombin; (3) tissue inhibitor of matrix metalloproteinase-2 completely prevented gelatinase A activation induced by PMA but not by thrombin; and (4) the metalloproteinase inhibitor 1,10-phenanthroline did not inhibit thrombin-induced activation. Together, these data demonstrate that activation of gelatinase A by thrombin is different from PMA and operating via a pathway independent of MT1-MMP. The ability of thrombin to rapidly and efficiently activate gelatinase A is likely to be a major contributing factor to its potent angiogenic activity.
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PMID:Thrombin rapidly and efficiently activates gelatinase A in human microvascular endothelial cells via a mechanism independent of active MT1 matrix metalloproteinase. 1021 99


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