Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.4.24.35 (matrix metalloproteinase 9)
 2,207 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Thickening of the tubular basement membrane is one of the hallmarks of the polycystic kidney disease (PKD). The present study was conducted to investigate the potential role of the matrix metalloproteinase-2 (MMP-2) and its specific tissue inhibitors (TIMP-1 and TIMP-2) in the accumulation of matrix components in PKD. As a model of PKD, two-month-old heterozygous Han:SPRD rats, which are at an early stage of cystogenesis, were used. MMP-2, but not MMP-9 (gelatinase B) nor MMP-3 (stromelysin) could be detected in proximal tubules of the normal rat kidney. The presence of the inhibitors TIMP-1 and TIMP-2 was confirmed on the mRNA level. In tubules from PKD rats MMP-2 activity was lower (31 +/- 8 vs. 58 +/- 7 U/prep., N = 9, P < 0.05), mRNA of MMP-2 was reduced 4.2 +/- 0.6-fold (N = 4, P < 0.05) and enzyme protein was depressed 3.8 +/- 0.8-fold (N = 4, P < 0.05). By contrast, TIMP-1 mRNA was 9.0 +/- 1.1-fold and TIMP-2 mRNA 3.8 +/- 0.7-fold (N = 4, P < 0.05) elevated over controls. Cyst fluid from homozygous rats contained MMP-2 protein and activity. These findings indicate that tubular MMP-2 activity is reduced in PKD, due to down-regulation of MMP-2, up-regulation of TIMP-1 and TIMP-2, and luminal secretion of the enzyme. It is conceivable that these alterations relate to the enhanced matrix accumulation observed in the evolution of PKD.
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PMID:Tubular gelatinase A (MMP-2) and its tissue inhibitors in polycystic kidney disease in the Han:SPRD rat. 877 Sep 51

Matrix metalloproteinases participate in normal physiologic processes; however, their overproduction has been associated with connective tissue destruction in a variety of pathological states. Migrating basal keratinocytes transiently express collagenase-1 during normal cutaneous reepithelialization. However, the overexpression of both collagenase-1 and stromelysin-1 has been associated with the pathogenesis of chronic nonhealing ulcers. Aberrant expression of metalloproteinases in inflammation is mediated, at least in part, by soluble factors. Since hepatocyte growth factor/scatter factor (HGF/SF) has been reported to promote keratinocyte migration and proliferation, key events in wound repair, and since HGF/SF is produced by dermal fibroblasts and its c-Met receptor is expressed by basal keratinocytes in wounded skin, we have studied the effects of HGF/SF upon keratinocyte metalloproteinase expression. We have found that HGF/SF can stimulate keratinocyte collagenase-1 and stromelysin-1 production in a dose-dependent and matrix-dependent manner. Expression of 92-kDa gelatinase was not affected by HGF/SF. We determined that HGF/SF regulation of collagenase-1 expression is transcriptionally mediated and requires tyrosine kinase and protein kinase C activaties. HGF/NK1, a naturally occurring, truncated form of HGF/SF, also stimulates collagenase-1 production, but much less efficiently than does the parent molecule. However, HGF/NK2, another HGF/SF splice variant, as well as heparin, potently inhibit HGF/SF-induced collagenase-1 synthesis. These results indicate that HGF/SF and its naturally occurring splice variants have diverse biological effects on keratinocytes and suggest an additional mechanism whereby HGF/SF may regulate keratinocyte function during wound repair.
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PMID:Mechanisms of hepatocyte growth factor stimulation of keratinocyte metalloproteinase production. 879 21

Matrix metalloproteinases (MMPs) are zinc-dependent endopeptidases which are secreted from cells as zymogens and can be activated by treatment with organomercurial reagents or limited proteolysis. The proenzyme forms of MMP-2 (gelatinase A) and MMP-9 (gelatinase B) are found in complex with tissue inhibitor of metalloproteinases (designated proMMP-2/ TIMP-2 and proMMP-9/TIMP-1, respectively). The proposed mechanism of activation by mercurial compounds involves the induction of a conformational change in the zymogen which leads to propeptide autoprocessing. To investigate the possibility of conformational differences in MMPs, solute quenching of MMP intrinsic fluorescence was used to probe the relative exposure of tryptophan residues in latent and mercurial-activated MMPs. Our data demonstrate that fluorescence quenching of the proMMP-2/TIMP-2 complex by either acrylamide or iodide is significantly increased following mercurial activation. In contrast, no significant change in tryptophan accessibility accompanies mercurial treatment of either proMMP-2 or TIMP-2 alone, or mercurial-activated MMP-2 mixed with TIMP-2. To determine whether the enhanced fluorescence quenching was unique to the activated proMMP-2/TIMP-2 complex, similar experiments were performed using MMP-1, MMP-3, and MMP-9/TIMP-1 complex. In all cases, both latent and mercurialtreated MMPs exhibited similar fluorescence quenching profiles, suggesting that there are no significant conformational differences between the zymogen and activated forms of MMP-1, -2, -3, or -9/TIMP-1. The enhanced fluorescence quenching observed with mercurial-treated proMMP-2/TIMP-2 is indicative of increased exposure of a previously buried tryptophan residue(s), providing evidence for a structural rearrangement of the activated complex. These data, together with our previous biochemical observation that mercurial treatment of proMMP-2/TIMP-2 exposes the MMP-2 active site without propeptide processing (Y. Itoh et al. (1995) Biochem. J. 308, 645-651), suggest that the activated proMMP-2 in the complex may represent a transitional conformational intermediate in MMP activation.
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PMID:Fluorescence quenching studies of matrix metalloproteinases (MMPs): evidence for structural rearrangement of the proMMP-2/TIMP-2 complex upon mercurial activation. 880 67

Towards gene transfer-based therapies of renal glomerulonephritis, this study examines the feasibility of using a mesangial cell vector (J. Clin. Invest. 94, 497-505, 1994) engineered to secrete interleukin-1 receptor antagonist (IL-1ra). IL-1ra cDNA was introduced into cultured rat mesangial cells, and stably transfected vector cells were established. Compared to mock transfectants, the vector cells showed blunted expression of gelatinase B, stromelysin and monocyte chemoattractant protein-1 in response to IL-1 beta. The attenuated responses were transferable to untransfected cells by cross-feeding with vector cell-conditioned media. The vector cells were then delivered into the glomeruli of rats via the renal circulation. Compared to either unmodified or mock cell-containing glomeruli, the glomeruli transferred with vector cells showed repressed expression of gelatinase B in response to IL-1 beta. Transfer of vector cells thus conferred insensitivity to IL-1 on the glomerulus. This result indicates the feasibility of modifying glomerular microenvironment against certain pathogenic mediators via the ex vivo transfer of therapeutically-relevant genes to the glomerulus.
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PMID:Gene transfer of interleukin-1 receptor antagonist into the renal glomerulus via a mesangial cell vector. 883 5

In the present study, we examined the roles of the matrix metalloproteinases collagenase, 72-kDa and 92-kDa gelatinase, and proteoglycanase in the tissue remodeling that occurs during luteal development and regression, using a pseudopregnant rat model. Pseudopregnancy was induced in immature female rats by eCG/hCG priming, and animals (n = 3 to 4 per time point) were killed on Days 1, 2, 4, 8, 12, 14, or 16 of pseudopregnancy (Day 0 = time of hCG administration). Ovaries were then removed and analyzed for either matrix metalloproteinase mRNA expression or activity. During luteal development (Day 1 of pseudopregnancy), activity of both collagenase (p = 0.009) and gelatinase (p = 0.0003), but not proteoglycanase (p > or = 0.05), was significantly greater than at all other time points. In accord with gelatinase activity, transcript levels of this enzyme were elevated at Day 1 of pseudopregnancy. Specifically, gelatinase transcript levels for the 72-kDa and 92-kDa enzymes were greatest at Day 1 (p = 0.0003 and p = 0.001, respectively), decreased 3-fold by Day 2,4-fold by Day 4, and reached 10-fold lower levels by Days 8 and 12 of pseudopregnancy. Proteoglycanase transcript could not be detected by Northern analysis during luteal development or any other time point examined in the current study. During the period of luteal maintenance (approximately Days 4-8 of pseudopregnancy in the rat), collagenase and gelatinase displayed basal levels of activity, but only proteoglycanase activity was elevated compared to luteal development levels of this enzyme. During luteal regression (Days 12-14 of pseudopregnancy in the rat), all enzymes displayed basal levels of enzyme activity. In accord with gelatinolytic activity during luteal regression, both 72-kDa and 92-kDa gelatinase mRNA were detectable at baseline levels. In contrast to the baseline levels of collagenolytic activity during luteal regression, collagenase transcript displayed peak values (approximately 8-fold greater than Day 1 levels; p = 0.004) at Day 12 of pseudopregnancy. It is concluded from these studies that collagenase and the gelatinases play a role in the tissue remodeling associated with luteal development, proteoglycanase is associated with luteal maintenance, and collagenase may contribute to the structural regression of the corpus luteum.
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PMID:Collagenase, gelatinase, and proteoglycanase messenger ribonucleic acid expression and activity during luteal development, maintenance, and regression in the pseudopregnant rat ovary. 883 83

Gelatinase B is a regulated matrix metalloproteinase with important role in the remodeling of extracellular matrix and many pathological conditions such as tumor invasion and rheumatoid arthritis, physiological processes including embryonic growth and development, migration of blood leukocytes into tissues and tissue remodeling. Elevated levels of certain MMPs are believed to be associated with various pathological states. We cloned the 5'-flanking 600 bp sequence of human gelatinase B gene by PCR, which controls the expression of the gene by ligating it to the chloramphenicol acetyltransferase gene. Four kinds of cell lines were used to transiently transfect. Deletion analysis revealed that 100 bp (-600 to -500 bp) contributed positively to induction by tumour necrosis factor. The 100 bp contains NF-kappa B site, Ap-1 site, PEA3 and Sp-1 site. The expression of the human gelatinase B gene varied in different cells in the presence of TNF.NF-kappa B factor may play an important role in regulating the gene expression. Comparison of the finding with those for the promoter of gelatinase A, collagenase and stromelysin shows that the determinant for the inducibility of the gelatinase B gene is more complex.
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PMID:Molecular mechanism of transcriptional activation of human gelatinase B by proximal promoter. 884 71

Delayed re-epithelialization of the cornea after injury usually precedes stromal ulceration. Previous findings using a rat thermal injury model suggested that re-epithelialization is impeded by products of resident corneal cells, which destroy adhesive structures at the basement membrane zone. In this study, we provide additional evidence for this concept. Failure to re-epithelialize was found to correlate with an increase in the amounts of gelatinolytic matrix metalloproteinases present in the rat cornea. One of these gelatinases, gelatinase B, is synthesized by the resident corneal cells, and inhibitions of its synthesis correlated with inhibition of basement membrane dissolution. The matrix metalloproteinases collagenase and stromelysin are also synthesized by resident corneal cells in thermally injured corneas of rabbits, but the timing of bulk enzyme synthesis correlated more closely with deposition of repair tissue in the stroma than with failure to re-epithelialize. Nevertheless, in human corneas with repair defects, gelatinase B and collagenase are synthesized by cells in the basal layer of the epithelium directly adjacent to the basement membrane, suggesting that both could participate in dissolution of this structure. Importantly, treatment of thermally injured corneas with a synthetic inhibitor of matrix metalloproteinases significantly improved basement membrane integrity. These data support the concept that over-expression of matrix metalloproteinases by resident corneal cells impedes re-epithelialization after some types of corneal injury.
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PMID:Role of matrix metalloproteinases in failure to re-epithelialize after corneal injury. 886 76

Macrophages are present in inflammatory tissue sites where abnormal degradation of the extracellular matrix takes place. To evaluate the potential of macrophages to participate in such matrix destruction, we studied the effects of three cytokines present in inflammatory tissue sites, TNF-alpha, IL-1beta, and IFN-gamma, on the production of three matrix-degrading metalloproteinases, interstitial collagenase, stromelysin, and 92-kDa gelatinase, as well as their natural inhibitor, TIMP-1 (tissue inhibitor of metalloproteinases number 1), by human monocyte-derived macrophages differentiated in vitro. Spontaneous production of interstitial collagenase and stromelysin by these cells was minimal, and was not influenced by the cytokines. In contrast, the cells secreted substantial basal amounts of 92-kDa gelatinase, the secretion of which was stimulated (2- to 15-fold; on average 5-fold) by both TNF-alpha and IL-1beta, while the production of TIMP-1 was unaffected. IFN-gamma suppressed the production of the 92-kDa gelatinase induced by TNF-alpha- and IL-1beta. TNF-alpha and IL-1beta regulated the expression of 92-kDa gelatinase by monocyte-derived macrophages at the pretranslational level. The results show that expression of 92-kDa gelatinase, but not its natural inhibitor TIMP-1, by human tissue-type macrophages is selectively up-regulated by proinflammatory cytokines; which suggests that these cells, when actually present in an inflammatory environment, will actively participate in the destruction of the extracellular matrix.
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PMID:TNF-alpha and IL-1beta selectively induce expression of 92-kDa gelatinase by human macrophages. 889 53

In neurodegenerative disease or after brain injury, parenchymal cells in the central nervous system are activated to produce inflammatory mediators, mainly consisting of cytokine-induced factors, in a manner similar to, but clearly different from a peripheral inflammatory response. The upregulated expression of several extracellular matrix proteins in astrocytes located surrounding a neuritic plaque in Alzheimer's disease is a good example of such a response. A family of mediators which is cytokine-induced during an inflammatory response in the periphery are the matrix metalloproteinases. Matrix metalloproteinases are calcium-requiring, zinc-containing endopeptidases that constitute a major component of the enzyme cascade responsible for degradation of extracellular matrix proteins such as collagen, proteoglycan and laminin. Little is known about the cellular source or the function of matrix metalloproteinases in the central nervous system or how their expression is regulated in brain. Thus, it was of interest to determine which factors of the so-called 'brain inflammatory response' regulate the expression of these proteases in the nervous system. To this end, we measured the expression of matrix metalloproteinases in cultured rat astrocytes and microglia after treatment with various cytokines. Interleukin-1 beta, tumor necrosis factor-alpha and lipopolysaccharide were potent stimulators of matrix metalloproteinase-2 (gelatinase A) and matrix metalloproteinase-9 (gelatinase B) in cultured rat astrocytes; the effect of each secretagogue was inhibited in the presence of glucocorticoid. Interleukin-1 beta and lipopolysaccharide also stimulated the production of matrix metalloproteinase-3 (stromelysin-1) in astrocytes. In addition, activated microglia release matrix metalloproteinase-9. The 'coactivator' of monocytic phagocytes, interferon-gamma, rather than augmenting the response to lipopolysaccharide, inhibited it. Thus, cytokines appear to be potent regulators of matrix metalloproteinase production in astrocytes and microglia. The presence of these enzymes in 'inflamed' central nervous system may suggest their involvement in the pathogenesis or progression of neurodegenerative diseases which are associated with an inflammatory component. Much remains to be learned about the potential substrates for these enzymes and the mechanism of their activation in the central nervous system.
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PMID:Regulation of matrix metalloproteinase expressions in astrocytes, microglia and neurons. 894 20

Injury to a peripheral nerve is followed by a remodeling process consisting of axonal degeneration and regeneration. It is not known how Schwann cell-derived basement membrane is preserved after injury or what role matrix metalloproteinases (MMPs) and their inhibitors play in axonal degeneration and regeneration. We showed that the MMPs gelatinase B (MMP-9), stromelysin-1 (MMP-3), and the tissue inhibitor of MMPs (TIMP)-1 were induced in crush and distal segments of mouse sciatic nerve after injury. TIMP-1 inhibitor activity was present in excess of proteinase activity in extracts of injured nerve. TIMP-1 protected basement membrane type IV collagen from degradation by exogenous gelatinase B in cryostat sections of nerve in vitro. In vivo, during the early phase (1 d after crush) and later phase (4 d after crush) after injury, induction of TNF-alpha and TGF-beta 1 mRNAs, known modulators of TIMP-1 expression, were paralleled by an upregulation of TIMP-1 and gelatinase B mRNAs. At 4 days after injury, TIMP-1, gelatinase B, and TNF-alpha mRNAs were localized to infiltrating macrophages and Schwann cells in the regions of nerve infiltrated by elicited macrophages. TIMP-1 and cytokine mRNA expression was upregulated in undamaged nerve explants incubated with medium conditioned by macrophages or containing the cytokines TGF-beta 1, TNF-alpha, and IL-1 alpha. These results show that TIMP-1 may protect basement membrane from uncontrolled degradation after injury and that cytokines produced by macrophages may participate in the regulation of TIMP-1 levels during nerve repair.
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PMID:Basement membrane and repair of injury to peripheral nerve: defining a potential role for macrophages, matrix metalloproteinases, and tissue inhibitor of metalloproteinases-1. 897 86


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