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)

Degradation of the extracellular basement membrane is implicated in atherosclerosis, restenosis after angioplasty, and intimal thickening of vein grafts. Upregulation of metalloproteinase (MMP)-2 and MMP-9 accompanies neointima formation in cholesterol-fed rabbits, in rat and pig models of angioplasty, and in organ cultures of human saphenous veins. MMPs are inhibited by binding to tissue inhibitors of MMPs (TIMPs). Relatively little is known about their regulation in relationship to neointima formation; thus, we investigated TIMP expression in the organ culture model. Qualitative reverse transcriptase-polymerase chain reaction of mRNA extracted from veins showed that TIMP-1, TIMP-2, and TIMP-3 are each expressed before and after culture. Zymography revealed that TIMP-1 was the most abundant TIMP secreted and that its secretion increased dramatically between 0 to 2 and 12 to 14 days of culture. An enzyme-linked immunosorbent assay showed that TIMP-1 secretion increased from 3.2+/-1.5 (mean+/-SE) to 32+/-6 ng/mg wet weight per day (n=5, P<0.01). Immunocytochemical testing localized the increased expression of TIMP-1 to neointimal smooth muscle cells. Although less abundant, TIMP-2 secretion also increased from 0.8+/-0. 3 to 4.7+/-0.2 ng/mg wet weight per day (n=5, P<0.001), and tissue levels increased from 33+/-7 to 150+/-70 ng/mg wet weight (P<0.05). TIMP-2 was also immunolocalized to neointimal smooth muscle cells and their surrounding matrix. TIMP-3 was not secreted but was detected variably and constitutively in tissue extracts (160+/-120 and 170+/-100 ng/mg wet weight [n=9] on days 2 and 14, respectively). TIMP-3 was found in the cells and extracellular matrix of the media and adventitia before culture and to a lesser extent in the neointima after 14 days of culture. Rates of total TIMP secretion on day 14 exceeded those of MMP-2 and MMP-9 (10.6+/-1.9 and 15.6+/-2.3 ng/mg wet weight per day, respectively). Consistent with this, in situ zymography showed that MMP gelatinase activity was highly localized to cell bodies in the media and neointima. Secretion of TIMP-1 and TIMP-2 is greatly increased during neointima formation in human saphenous veins. TIMP-1 is readily released, whereas TIMP-2 remains partially attached and TIMP-3 exclusively attached to the extracellular matrix. Regulation of TIMP expression is therefore an important determinant of net MMP activity during neointima formation, restricting it to the pericellular environment.
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PMID:Expression of tissue inhibitor of metalloproteinase-1, -2, and -3 during neointima formation in organ cultures of human saphenous vein. 997 5

A method was developed for generating soluble, active "aggrecanase" in conditioned media from interleukin-1-stimulated bovine nasal cartilage cultures. Using bovine nasal cartilage conditioned media as a source of the aggrecanase enzyme, an enzymatic assay was established employing purified aggrecan monomers as a substrate and monitoring specific aggrecanase-mediated cleavage products by Western analysis using the monoclonal antibody, BC-3 (which recognizes the new N terminus, ARGS, on fragments produced by cleavage between amino acid residues Glu373 and Ala374). Using this assay we have characterized cartilage aggrecanase with respect to assay kinetics, pH and salt optima, heat sensitivity, and stability upon storage. Aggrecanase activity was inhibited by the metalloprotease inhibitor, EDTA, while a panel of inhibitors of serine, cysteine, and aspartic proteinases had no effect, suggesting that aggrecanase is a metalloproteinase. Sensitivity to known matrix metalloproteinase inhibitors as well as to the endogenous tissue inhibitor of metalloproteinases, TIMP-1, further support the notion that aggrecanase is a metalloproteinase potentially related to the ADAM family or MMP family of proteases previously implicated in the catabolism of the extracellular matrix.
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PMID:Generation and characterization of aggrecanase. A soluble, cartilage-derived aggrecan-degrading activity. 1003 54

Acidic fibroblast growth factor (FGF-1), a prototype member of the heparin-binding growth factor family, influences proliferation, differentiation, and protein synthesis in different cell types. However, its possible role on lung extracellular matrix (ECM) metabolism has not been evaluated. In this study we examined the effects of FGF-1 and FGF-1 plus heparin on type I collagen, collagen-binding stress protein HSP47, interstitial collagenase (matrix metalloproteinase [MMP]-1), gelatinase A, and tissue inhibitor of metalloproteinase (TIMP)-1 and TIMP-2 expression by normal human lung fibroblasts. Heparin was used because it enhances the biologic activities of FGF-1. Fibroblasts were exposed either to 20 ng/ml FGF-1 plus 100 micrograms/ml heparin for 48 h or to FGF-1 or heparin alone. Messenger RNA (mRNA) expression was analyzed by Northern blot. Collagen synthesis was evaluated by digestion of [3H]collagen with bacterial collagenase, MMP-1 by Western blot, and gelatinolytic activities by zymography. Our results show that FGF-1 induced collagenase mRNA expression, which was strongly enhanced when FGF-1 was used with heparin. Likewise, both FGF-1 and FGF-1 plus heparin reduced by 70 to 80% the expression of type I collagen transcript, in part through effect on pro-alpha1(I) collagen mRNA stability. A downregulation of HSP47 gene expression was also observed. Synthesis of collagen and collagenase proteins paralleled gene expression results. FGF-1 activities were abolished with genistein, a tyrosine kinase inhibitor. Neither FGF-1 nor FGF-1 plus heparin affected the expression of TIMP-1, TIMP-2, and gelatinase A. These findings demonstrate that FGF-1, mostly in the presence of heparin, upregulates collagenase and downregulates type I collagen expression that might have a protective role in avoiding collagen accumulation during lung ECM remodeling.
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PMID:Acidic fibroblast growth factor induces an antifibrogenic phenotype in human lung fibroblasts. 1022 73

The insulin-like growth factors (IGFs) in adult mammalian plasma circulate predominantly in 150-kDa complexes that also contain IGF-binding protein-3 (IGFBP-3) and an acid-labile subunit. Proteolysis of IGFBP-3 within the 150-kDa complex decreases its affinity for IGFs, facilitating their release to the tissues. By contrast, 150-kDa complexes are not detected in serum from fetal or pregnant adult rats. Decreased complex formation results from insufficient availability of IGFBP-3 due to increased IGFBP-3 proteolysis. The present study characterizes IGFBP-3 protease activity in serum from fetal, pregnant and non-pregnant adult rats by comparing the effect of different protease inhibitors. Proteolysis of exogenous recombinant human IGFBP-3 (for fetal and pregnancy serum) or endogenous IGFBP-3 (for non-pregnant adult rat serum) following incubation at 37 degrees C was measured by ligand blotting. In all three sera, IGFBP-3 proteolysis was inhibited completely by: (i) EDTA, a chelator of divalent cations. Inhibition was reversed by zinc, but not by calcium ions; (ii) 4-(2-aminoethyl)-benzenesulfonyl fluoride (AEBSF), an inhibitor of serine proteases; and (iii) a specific tissue inhibitor of matrix metalloproteinases (TIMP-1). Recombinant human matrix metalloproteinase-3 (MMP-3) proteolyzed recombinant human IGFBP-3 or endogenous rat IGFBP-3 in non-pregnancy serum pretreated with AEBSF to inactivate endogenous serine proteases. These results suggest that serine proteases initiate the activation of latent MMP precursor, and that the activated MMP directly degrades IGFBP-3.
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PMID:Proteolysis of insulin-like growth factor binding protein-3 in serum from pregnant, non-pregnant and fetal rats by matrix metalloproteinases and serine proteases. 1022 1

Since proteolysis of the dermal collagenous matrix and basement membranes is required for local invasive growth and early metastasis formation of cutaneous melanomas, we have analysed the activities/expression levels of certain metalloproteinases in melanomas and cultured melanoma cells by in situ hybridization and Northern analysis. In addition to collagenases-1 and -3 that have been implicated in invasive growth behaviour of various malignant tumours, we analysed the levels of 72-kDa gelatinase and its activators MT1-MMP and TIMP-2 in cultured melanoma cells. The lesions examined included three cases of lentigo maligna and 28 cases of Clark grade I-V melanomas. The premalignant as well as the grade I tumours were consistently negative for collagenase-1 and -3 and TIMP-1 and -3. The collagenases were predominantly expressed in the cancer cells of Clark grade III and IV tumours. TIMP-1 and -3 were abundantly expressed in the cancer and/or stromal cells of grade III and IV melanomas, while TIMP-2 protein was detected also in melanomas representing lower invasive potential. Northern analysis of seven melanoma cell lines showed that the expression of collagenase-1 and TIMPs-1 and -3 was associated with 72-kDa gelatinase positivity. All melanoma cell lines were positive for MT1-MMP and TIMP-2 mRNAs. Our results suggest that overexpression of collagenases-1 and -3 and TIMPs-1 and -3 is induced during melanoma progression. Expression of TIMPs may reflect host response to tumour invasion in an effort to control MMP activity and preserve extracellular matrix integrity.
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PMID:Expression of collagenases-1 and -3 and their inhibitors TIMP-1 and -3 correlates with the level of invasion in malignant melanomas. 1036 Jun 51

Progesterone appears essential for ovulation and luteinization of the primate follicle, but specific gene targets of progesterone action remain elusive. Limited evidence supports a role for progesterone in the induction of collagenolytic activity in the periovulatory follicle of primate and nonprimate species. This study was designed to elucidate the pattern of expression and progesterone regulation of mRNAs for the matrix metalloproteinases (MMPs) and their tissue inhibitors (TIMPs) in macaque granulosa cells during controlled ovarian stimulation cycles before (0 h) and after (up to 36 h) administration of an ovulatory hCG bolus. Levels of mRNAs for interstitial collagenase, gelatinase A, matrilysin, TIMP-1 and TIMP-2 increased (p < 0.05) within 12 h of hCG, while gelatinase B mRNA increased later, by 36 h after hCG. Administration of a 3beta-hydroxysteroid dehydrogenase inhibitor (Trilostane [TRL]) during hCG treatment decreased (p < 0.05) mRNA levels for interstitial collagenase, gelatinase B, matrilysin, TIMP-1, and TIMP-2. Progestin (R5020) replacement during hCG+TRL treatment returned interstitial collagenase and TIMP-1 mRNAs to control levels. These data suggest that one action of progesterone, and possibly other steroids, in the cascade of events leading to ovulation and luteinization of the primate follicle is to regulate the expression of specific ovarian proteases and protease inhibitors.
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PMID:Expression of matrix metalloproteinases and their tissue inhibitor messenger ribonucleic acids in macaque periovulatory granulosa cells: time course and steroid regulation. 1037 26

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

Elevated MMP activities are implicated in tissue degradation in, e.g., arthritis and cancer. The present study was designed to measure MMP enzyme activity in plasma. Free active MMP is unlikely to be present in plasma: upon entering the circulation, active MMP is expected to be captured by the proteinase inhibitor alpha 2-macroglobulin (alpha 2M). Reconstituted MMP-13/alpha 2M complex was unable to degrade collagen (MW 300,000) in contrast to the low-molecular-weight fluorogenic substrate (MW < 1500). Limited access of high-MW substrates to the active site of MMPs captured by alpha 2M presents the most likely explanation. Consistently, the high-MW inhibitor TIMP (MW approximately 28,000) was unable to inhibit MMP/alpha 2M enzyme activity, whereas the low-MW inhibitor BB94 (MW approximately 500) effectively suppressed enzyme activity. By using fluorogenic substrates with Dabcyl/Fluorescein as quencher/fluorophore combin-ation, sensitive MMP-activity assays in plasma were achieved. Spiking of active MMP-13 and MMP-13/alpha 2M complex, and inhibitor studies with TIMP-1 and BB94, indicated that active MMPs are efficiently captured by alpha 2M in plasma. MMP activity was even detected in control plasma, and was significantly increased in plasma from rheumatoid arthritis patients.
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PMID:Fluorogenic MMP activity assay for plasma including MMPs complexed to alpha 2-macroglobulin. 1041 27

Matrix metalloproteinases are proteolytic enzymes which play a major role in resorption of collagen and other components of the extracellular matrix. They are controlled by specific inhibitors, so-called tissue inhibitors of metalloproteinases (TIMPs). The balance between matrix metalloproteinases and TIMPs seems to play a major role in controlling extracellular matrix homeostasis and cell migration. The influence of TIMP-1 on migration behaviour was explored in human hepatoma cells transiently and stably transfected with mouse TIMP-1, and incubated with biologically active TIMP-1. Transfection and biosynthesis were verified by Northern blotting, Western blotting, metabolic labeling, and reverse zymography. Overexpression of and incubation with TIMP-1 resulted in suppressed migration and seemed to enhance cell-cell contact. Using gelatin zymography and Western blotting we measured a significant increase of matrix metalloproteinases-2 and matrix metalloproteinases-9 in cells transfected with TIMP-1. This new phenomenon may be of important physiological significance in modulating TIMP and MMP expression. Our results indicate a functional involvement of TIMP-1 in matrix homeostasis and some automatic control in matrix turnover.
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PMID:Increased TIMP-1 activity results in increased expression of gelatinases and altered cell motility. 1050 6

Nonenzymatic glycation of extracellular matrix (ECM) proteins is increased in diabetes mellitus and aging and triggers cellular events leading to an imbalance in ECM homeostasis. We studied the influence of collagen glycation on matrix metalloproteinase production by dermal fibroblasts using the model of lattice cultures. Contraction of glycated collagen lattices was strongly reduced when compared to controls. Meanwhile, fibroblasts synthesized lower amounts of interstitial collagenase (MMP-1). Gelatinase A (MMP-2) production was not modified, but its activation was strongly inhibited. These effects were independent from the intensity of lattice contraction and from any simultaneous modification of tissue inhibitors of metalloproteinase (TIMP-1 and 2) production. These results demonstrate that the impaired ability of fibroblasts to remodel and contract a glycated extracellular matrix coincides with a decrease in MMP production.
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PMID:Decreased contraction of glycated collagen lattices coincides with impaired matrix metalloproteinase production. 1052 90


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