Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:3.4.24.17 (MMP-3)
3,419 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Epidermal growth factor (EGF) is a ubiquitous fibroblast mitogen which also stimulates the synthesis of the extracellular matrix degrading metalloproteinases, collagenase, and stromelysin. Using primary cultures of human skin fibroblast, we show that these metalloproteinase mRNAs are coordinately up-regulated by EGF; and that dexamethasone, a potent inhibitor of collagenase and stromelysin synthesis, coordinately down-regulates these EGF-induced mRNAs. Nuclear run-on assays showed that EGF increased transcription of collagenase and stromelysin approximately 2-fold over the untreated control, while repression by dexamethasone was difficult to detect. However, steady state mRNA levels were induced approximately 10-fold by EGF and co-treatment with dexamethasone decreased them to below control levels, suggesting modulation of mRNA stability. Thus, we measured the half-life of these mRNAs using "pulse-chase" methodology. Typically, the half-life of EGF-induced collagenase and stromelysin mRNAs was approximately 30 h, and co-treatment with dexamethasone decreased the half-life of these mRNAs by 30-50%. Additionally, we found that the transcription inhibitor DRB stabilized EGF-induced metalloproteinase mRNAs, suggesting an mRNA degradation pathway which requires transcription. Thus our data demonstrate that collagenase and stromelysin are coordinately regulated by EGF and by dexamethasone, primarily at the level of metalloproteinase mRNA stability.
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PMID:Post-transcriptional regulation of collagenase and stromelysin gene expression by epidermal growth factor and dexamethasone in cultured human fibroblasts. 146 71

We studied tissue samples of noninfected delayed union or nonunion of diaphyseal bones in 10 patients immunopathologically and neuroimmunologically 4 to 25 months after the primary injury. Samples mostly consisted of vascularized connective tissue of varying density with the proline-4-hydroxylase-containing fibroblast as the major cell type. Most inflammatory cells were CD4 T-lymphocytes and their number was always twice that of the CD8 positive cells. Staining for CD11b positive monocyte/macrophages showed in all samples positive cells scattered in the connective tissue stroma with perivascular enrichments. Mast cells were absent or very rare. Our findings suggest that delayed union and nonunion tissue consists of vascularized connective tissue, which mostly contains 5B5 fibroblasts, CD11b macrophages and vascular endothelial cells with only few immigrant recently recruited monocytes or lymphoid cells. Almost all resident cells seem to be involved in tissue remodeling as suggested by their content of fibroblast-type MMP-1 and its proteolytic activator MMP-3 or stromelysin. The most striking finding was the paucity or total lack of peripheral innervation, which may have to do with the nonunion of the fracture.
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PMID:Immunologic studies of nonunited fractures. 147

To probe the specificity of the metalloendoproteinase stromelysin toward peptide substrates, we determined kc/Km values for the stromelysin-catalyzed hydrolyses of peptides whose design was based loosely on the structure of a known SLN substrate, substance P (Arg-Pro-Lys-Pro-Gln-Gln-Phe-Phe-Gly-Leu-MetNH2, hydrolysis at Gln-Phe, kc/Km = 1700 M-1 s-1). Several noteworthy points emerge from this study: (i) Catalytic efficiency is dependent on peptide chain length with N-terminal truncation of substance P resulting in more pronounced rate-constant reductions than C-terminal truncation. These results suggest the existence of an extended active site for stromelysin. (ii) Preferences at positions P3, P2, P1, P1', and P2' are for the hydrophobic amino acids Pro, Leu, Ala, Nva, and Trp, respectively. (iii) Investigation of specificity at P3' supports our earlier hypothesis that SLN has a requirement for a hydrogen-bond donor at this position in its substrates. Based on these observations, we designed and had synthesized the fluorogenic substrate N-(2,4-dinitrophenyl)Arg-Pro-Lys-Pro-Leu-Ala-Nva-TrpNH2, whose stromelysin-catalyzed hydrolysis can be monitored continuously (kc/Km = 45,000 M-1 s-1).
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PMID:Substrate specificity of the human matrix metalloproteinase stromelysin and the development of continuous fluorometric assays. 147 98

Atherosclerotic lesions contain macrophages, smooth muscle cells and endothelial cells, all of which participate in lesion development. Upon stimulation these cells express a variety of different factors and receptors which are involved in lipid metabolism, cellular proliferation, tissue repair, immune response and inflammatory reactions. During the last few years, active expression of several genes has been reported in developing atherosclerotic lesions. These genes include scavenger receptor, 15-lipoxygenase, monocyte chemoattractant protein-1, macrophage colony stimulating factor-1, lipoprotein lipase, platelet-derived growth factor, tissue factor, apolipoprotein E, stromelysin, different adhesion molecules and various cytokines. Evidence continues to grow that the pattern of gene expression and the functional status of cells in different regions of atherosclerotic lesions may differ considerably and could be regulated by local factors present in atherosclerotic lesions. One such a powerful factor which may contribute to the regulation of gene expression in developing lesions is oxidized LDL which has been shown to affect the expression of cytokines, growth factors and chemotactic factors by arterial cells. Recent developments in the analysis of gene expression in the artery wall at the cellular level will undoubtedly increase our understanding about the sequence of events leading to the formation of atherosclerotic lesions.
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PMID:Gene expression in atherosclerotic lesions. 147 13

Stromelysin and stromelysin 2, closely related members of the metalloproteinase gene family degrade many non-collagenous components of the extracellular matrix and may play a role in the activation of latent procollagenase. Because we use monolayer cultures of rabbit and human fibroblasts as model systems to study these enzymes, we compared their expression in fibroblasts from both species. Rabbit stromelysin purified from fibroblast culture medium often appears as a protein doublet, while human stromelysin is a single protein band. Hybrid selection with a cDNA clone for rabbit stromelysin and in vitro translation of mRNA from rabbit fibroblasts stimulated with phorbol myristate acetate (PMA) reveals two translation products, Mr54 and 56KD, as measured by SDS polyacrylamide gel electrophoresis. In vitro transcription and translation of a 1.8 kb cDNA for rabbit stromelysin gives a single protein product, preprostromelysin, MR 56KD. We do not yet know whether the rabbit doublet represents two distinct gene products or whether it results from posttranscriptional/posttranslational processing of a single transcript or protein. To study human stromelysin, we cloned a cDNA from a rheumatoid synovial cell cDNA library and we used it to isolate genes for stromelysin and a related gene, stromelysin-2. Both genes are contained on approximately 14 kilobase pairs of DNA. With an exon containing fragment of the human stromelysin-2 genomic clone as a specific probe in Northern blot analysis, we demonstrate the differential expression of stromelysin and stromelysin 2 in rheumatoid synovial cells, human foreskin fibroblasts, and rabbit synovial fibroblasts. Chimeric constructs containing 302 bp of the human stromelysin promoter DNA linked to the bacterial gene chloramphenicol acetyl transferase (CAT) can be induced by PMA, epidermal growth factor (EGF) and interleukin-1 beta (IL-1 beta). Since the genes for stromelysin and stromelysin 2 are so conserved and since mechanisms regulating their expression appear to be distinctive, identification of these mechanisms in both rabbits and humans will increase our understanding of the relative role of these enzymes in normal and disease processes.
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PMID:Expression of stromelysin and stromelysin-2 in rabbit and human fibroblasts. 148 18

Expression of the rat stromelysin (transin) gene is stimulated by growth factors such as epidermal growth factor (EGF) and platelet-derived growth factor (PDGF), and inhibited by transforming growth factor-beta (TGF beta). Stimulation by both EGF and PDGF requires the presence of factors that recognize the AP-1 binding site in the stromelysin promoter, but PDGF stimulation requires induction of the protooncogene c-fos, while EGF acts through a FOS-independent pathway. The FOS-independent pathway appears to involve protein kinase C (PKC), since EGF, but not PDGF, requires activated protein kinase C to stimulate stromelysin expression. TGF beta inhibition of stromelysin gene expression requires an upstream sequence, referred to as the TGF beta inhibitory element (TIE). FOS is also a part of a protein complex that binds to the TIE. The protooncogene FOS is therefore involved in both stimulation and inhibition of stromelysin gene expression.
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PMID:The role of C-Fos in growth factor regulation of stromelysin/transin gene expression. 148 19

Extracellular matrix metalloproteases are synthesized as proenzymes and are activated by certain physiological agents after secretion into the extracellular space. The identity of these agents and the stimulus that elicits their response in vivo is only recently becoming clear, but a variety of agents or stimuli are capable of activating these metalloproteases in vitro also. Of these, the most well studied and characterized are trypsin, plasmin and the organomercurials. These agents appear to have in common an ability to disrupt the structure of the stable latent enzyme in such a way as to allow the generation of a proteolytic active site. In the case of organomercurial activation, intramolecular proteolytic cleavage of the amino-terminus of the enzyme occurs subsequent to generation of activity. A similar intramolecular process is seen with trypsin and plasmin activation except that it is initiated by a single trypsin or plasmin catalyzed cleavage in the amino-terminus prior to the autocatalytic cleavages. A possible explanation for organomercurial activation is that the mercurial disrupts a cysteinyl residue coordination bond with the active site zinc that prevents interaction with substrate. Disruption of this complex would allow productive enzyme-substrate interaction via the newly available coordination site. In addition, activated stromelysin is capable of increasing the specific activity of active interstitial collagenase by approximately ten-fold through what appears to be proteolytic removal of a small peptide.
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PMID:Activation of extracellular matrix metalloproteases by proteases and organomercurials. 148 30

The activation of procollagenase and prostromelysin by mechanisms that might be functional in vivo has been investigated. Studies with cell monolayers plated onto collagen films have indicated key roles for plasmin and TIMP in these processes. Prostromelysin activation could be rapidly effected by fibroblast monolayers in the presence of plasminogen, with identical kinetics to plasminogen-streptokinase generated plasmin. Procollagenase activation by plasmin was shown to be poor, although an M(r) shift of 11,000 occurred. Activation was enhanced ten-fold by the presence of active stromelysin even at a very low molar ratio. A tumour cell line secreting procollagenase but not stromelysin was found to be dependent upon the addition of both stromelysin and plasminogen to effect degradation of collagen films. Biochemical studies of metalloproteinase activation were carried out using other purified proteinases synthesized by connective tissue cells including endopeptidase 24.11, endopeptidase-2, cathepsin B and cathepsin L. None was a particularly effective activator relative to plasmin, but cathepsin B was shown to activate stromelysin. By use of both cell model systems and biochemical studies of purified enzymes we have found that the role of plasmin as the major metalloproteinase activator in normal connective tissue cells remains unchallenged.
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PMID:Physiological mechanisms for metalloproteinase activation. 148 31

The zymogens of matrix metalloproteinase 1 (MMP-1: tissue collagenase), MMP-2 (gelatinase/type IV collagenase) and MMP-3 (stromelysin) were purified from the culture medium of human rheumatoid synovial fibroblasts and the mechanisms of activation of each zymogen by proteinases and 4-aminophenylmercuric acetate (APMA) were studied by kinetic and sequence analyses. The treatment of proMMP-1 (M(r) = 52,000) with proteinases or APMA converted the zymogen to M(r) = 43,000, but it exhibited only 14-25% of the maximal activity. Incubation of a partially active MMP-1 with MMP-3 resulted in rapid, full activation by generating the 41,000-M(r) MMP-1 with Phe81 as the NH2-terminus. MMP-3 directly activated proMMP-1 by cleaving the Gln80-Phe81 bond, but this reaction was extremely slow, indicating that the Gln80-Phe81 bond is not readily available to MMP-3 in the native proMMP-1 molecule. ProMMP-2 (M(r) = 72,000) was activated only by APMA, but not by proteinases. The activation by APMA was rapid and generated an active MMP-2 of M(r) 68,000, but the enzymic activity declined rapidly after activation by autolysis. The NH2-terminal sequence analysis of active MMP-2 indicated that the Asn80-Tyr81 bond was cleaved upon APMA treatment. In contrast, proMMP-3 (M(r) = 57,000) was activated by a variety of proteinases with different specificities. The initial attacks of these proteinases are on a stretch of highly charged groups at the position 34-39 in the propeptide.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Activation mechanisms of the precursors of matrix metalloproteinases 1, 2 and 3. 148 33

Procollagenase M(r) 85,000 (SDS-PAGE) was purified from buffy coat to homogeneity and represents a stable single polypeptide chain forming the entire proenzyme. The procollagenase can be activated by various proteinases, e.g. trypsin, chymotrypsin, cathepsin G, kallikrein and stromelysin and by different mercurial compounds. Proteolytic conversion of the latent enzyme to the active form by chymotrypsin is accompanied by a molecular weight reduction to an apparent M(r) 64,000. This active enzyme lacks the first 79 N-terminal residues. Activation by trypsin leads to a latent intermediate of apparent M(r) 70,000, lacking 48 N-terminal residues. The active enzyme is therefore generated upon prolonged incubation with trypsin by further cleavage of 22 N-terminal residues. Another latent intermediate form with apparent M(r) 69,000 is generated from the proenzyme upon incubation with leukocyte elastase by N-terminal cleavage of 53 or 64 residues, respectively. However, latent collagenase cannot be activated by plasmin. Activation by different mercurial compounds finally results in the formation of active collagenase with apparent M(r) 64,000. In contrast to the proenzyme, active collagenase can autolyse to give active M(r) 57,000 and 45,000 intermediates and two M(r) 28,000 fragments. Purification of latent leukocyte gelatinase yields three final products with apparent M(r) 98,000, 125,000 and 220,000 (SDS-PAGE; non reduced). Upon reduction, only the M(r) 98,000 form can be detected. The latent gelatinase can be activated in a similar manner as collagenase. Proteolytic activation by trypsin leads after N-terminal cleavage to an active gelatinase with sequence homology to leukocyte collagenase.
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PMID:Latent collagenase and gelatinase from human neutrophils and their activation. 148 34


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