Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.4.24.3 (collagenase)
 18,340 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Prostaglandins, especially PGE2 and PGI2, appear to participate in the development of inflammatory reactions. While these PGs may act to promote inflammation, they may also inhibit immune reactions; this effect is largely related to stimulation of adenylate cyclase. Human rheumatoid synovial tissue explants and derived adherent synovial cells (ASC) in vitro produce large amounts of PG, primarily PGE2, which may participate in the pathogenesis of rheumatoid inflammation and promote the osteoclastic resorption of juxtaarticular bone. Rheumatoid synovial organ cultures are unusual in that they derive a significant proportion of archidonic acid substrate for the PGE2 synthesis from triglycerides, while ASC utilize primarily phospholipids. Aspirin-like, nonsteroidal anti-inflammatory drugs inhibit PGE2 synthesis by rheumatoid synovial organ cultures at concentrations similar to those achieved in plasma during therapy. Glucocorticoids are also potent inhibitors of PGE2 synthesis, and evidence from experiments with tissue labeled with 1-[14C]arachidonic acid indicates that glucocorticoids do not act to inhibit arachidonic acid release, as has been postulated for other tissues. Human peripheral blood mononuclear cells produce a factor (MCF) that regularly stimulates the production of PGE2 and collagenase from resting ASC often by over 100-fold. The MCF appears to be produced by monocytes, and its production by monocytes is enhanced by lectin-stimulated T-cells. The ability of ASC to respond to exogenous PGE2 stimulation of cAMP synthesis is inhibited or stimulated by factors that increase or decrease PGE2 levels, respectively, in the cultures. The MCF augments the responsiveness of cAMP response to PGE2 in indomethacin-treated cultures. These in vitro experiments suggest that the pathogenesis of rheumatoid inflammation involves interactions between monocyte-macrophages, lymphocytes, and synovial cells regulating the production of PGE2, cAMP, and other factors.
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PMID:Prostaglandins and their regulation in rheumatoid inflammation. 23 4

Extracellular matrix metalloproteases are secreted by the resident cells of the tissue in a proenzyme form, and their extracellular activity is regulated at the level of gene expression, proenzyme activation, and interaction with inhibitors. To understand the molecular mechanisms that control the activity of ECM metalloproteases and their effect on the cellular phenotype, we have established cell lines in which the transcription of the protease genes is repressed. We also have undertaken a detailed study of the pathway of extracellular activation of interstitial procollagenase. Stable transfection of three human tumor cell lines--H-ras-transformed bronchial epithelial cells TBE-1, fibrosarcoma cells HT1080, and melanoma cells A2058--with the adenovirus E1A gene dramatically repressed the expression of the secreted proteases, type IV and interstitial collagenases, and urokinase-type plasminogen activator. Concomitantly, E1A-expressing cells showed reduced metastatic activity in vivo and reduced ability to traverse a reconstituted basement membrane in vitro. Monospecific anti-type IV collagenase antibody inhibited the invasive activity of parental tumor cell lines in the in vitro system, suggesting a possible causal relationship between the effect of E1A on the expression of secreted proteases and the reduced metastatic potential of the E1A-expressing transformants. We have also studied the mechanism of regulation of metalloprotease activity at the level of extracellular activation by investigating the cascade of proteolytic events that results in the activation of interstitial procollagenase. Cocultivation of the major cellular components of skin, dermal fibroblasts, and epidermal keratinocytes induces activation of interstitial procollagenase and prostromelysin in the presence of plasminogen. This activation occurs through a uPA-plasmin-dependent pathway in which plasmin catalyzes the first step in activation of both collagenase and stromelysin by amino-terminal processing. Activated stromelysin can in turn convert plasmin-activated collagenase into a fully active enzyme by removal of approximately 15 amino acid residues from the carboxyl end of the enzyme. This second step of activation results in a 5-8-fold further increase in specific activity of collagenase. This cascade of proteolytic events may constitute a major physiologic pathway of collagenase activation.
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PMID:Secreted proteases. Regulation of their activity and their possible role in metastasis. 215 52

Inflammatory and 'non-inflammatory' forms of arthritis affect a large proportion of the population and these diseases can often lead to disability. Although the pain of arthritis can be relieved to some extent by the peripherally acting aspirin-like drugs, the progression of disease leading to joint destruction is largely resistant to current drug therapy. The synovial joints of patients with rheumatoid arthritis are infiltrated with neutrophils, macrophages and lymphocytes and the resident cells become activated to degrade the cartilage and bone. The inflammatory and destructive changes that occur are brought about by the action of mediators or local hormones which are produced by a variety of cell-types. Lipid mediators, such as prostaglandins, contribute to the symptoms of arthritis while polypeptide cytokines, such as interleukin 1 and tumour necrosis factor, play a key role in joint destruction by activating the synovial cells and chondrocytes to release metalloproteinases, such as collagenase. Aspirin-like drugs inhibit the production of prostaglandins from inflamed tissues and thereby blunt the symptoms of arthritis. However, these drugs do not suppress the production of collagenase from connective tissue cells and, therefore, do not halt the degeneration of joint tissues.
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PMID:Pathogenesis and treatment of chronic arthritis. 269 74

A method for long-term cultivation of large amounts of human microvascular endothelial cells from the omental tissue (human omental tissue microvascular endothelial cells, HOTMECs) was devised. The method originally described by Kern, Knedler, and Eckel was modified: HOTMECs were isolated by enzymatic dissociation with collagenase. For primary cultivation and passages, HOTMECs were plated either onto fibronectin-coated petri dishes or onto a human fibroblast extracellular matrix (HFB-ECM) prepared from the same tissue. Omental tissue (10-15 g) yielded 4-8 X 10(5) HOTMECs; more than 90% of the cells adhered to precoated dishes and grew in Waymouth's culture medium supplemented with 20% heat-inactivated fetal calf serum. Confluence was reached 3-5 days after seeding with an average of 1-2 X 10(6) cells/dish. Confluent HOTMEC layers were subcultured at a split ratio of 1:3 up to 11 passages by plating the cells onto dishes coated with HFB-ECM and maintained in long-term culture for up to 3 months. The endothelial origin of these cells was demonstrated as follows. The cells in culture showed the typical "cobblestone" growth pattern and synthesized von Willebrand factor (vWF) as determined by metabolic labeling. Using an indirect immunostaining technique, the cytoplasm of the HOTMECs stained for vWF. A monoclonal antibody specific for human endothelial cells bound exclusively to the cultured cells. The expression of thrombomodulin on the surface of the cultured cells was demonstrated by the activation of protein C by thrombin. In control experiments, these features could be detected on neither fibroblasts nor mesothelial cells.
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PMID:Microvascular endothelial cells from human omental tissue: modified method for long-term cultivation and new aspects of characterization. 282 81

The products of the collagen-alpha 1(I) and -alpha 2(I) genes form the triple helical molecule collagen type I, which constitutes the major ECM protein in tissue fibrosis. The collagen-alpha 1(I) gene is mainly transcriptionally regulated, and its promoter activity depends on the interaction of the transcription factors NF-I and Sp1 with a tandem repeat of evolutionary conserved NF-I/Sp1 switch elements. An increased affinity of Sp1 to these elements has been observed in experimental liver fibrosis. Here, we demonstrate that the DNA binding drug mithramycin displays a high affinity binding to the GC-rich elements in the collagen-alpha 1(I) promoter as measured by DNAse I protection and gel retardation assays. Mithramycin interferes with Sp1 but not with NF-I binding to these sites. At a concentration of 100 nM, mithramycin efficiently reduces basal and TGF-beta-stimulated alpha 1(I) gene expression in human primary fibroblasts. The transcriptional activity and mRNA steady state levels of other genes, including the collagenase gene, as well as the growth rate of fibroblasts remained unchanged on exposure to this drug. Taken together, our results indicate that the transcriptional activity of the type I collagen gene highly depends on its GC-rich regulatory elements, and further, that these elements can be differentially blocked, thereby changing the balance between ECM structural and degrading gene activities in human fibroblasts.
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PMID:Mithramycin selectively inhibits collagen-alpha 1(I) gene expression in human fibroblast. 1456 12

In the present study, we demonstrate that both interleukin-1 (IL-1) and interleukin-6 (IL-6) induced a significant decrease in glycosaminoglycan (GAG) synthesis and, more strikingly, secretion by 7 and 13 day-old chick embryo skin fibroblasts. We demonstrated that interleukin treatment also inhibited the synthesis of collagenase-digestible proteins (type I collagen). In addition, tissue culture supernatants (conditioned media, CM) were tested for reactivity for IL specific ELISAs and for their ability to stimulate proliferative responses in mouse thymocytes and hybridoma cells. Our findings demonstrate that chick embryo skin fibroblasts spontaneously produce IL-1 and, in even greater amounts, IL-6. Highest levels of interleukin secretion were found in the CM of 13 day-old fibroblasts and the IL-1 beta isoform was predominant over IL-1 alpha. Pretreatment of the fibroblasts with either IL-1 or IL-6 increased the secretion of both cytokines. Increased IL-1 levels were correlated with enhanced IL-1 bioactivity in the CM of IL-6 treated fibroblasts. By contrast, the raised concentrations of IL-1 in the CM of IL-1 treated cells and IL-6 in the CM of IL-1 or IL-6 treated fibroblasts failed to translate into augmented bioactivity. These observations, taken together, indicated that IL-1 and IL-6 are able to regulate the synthesis and secretion of ECM macromolecules of developing connective tissues and the cytokine release by chick embryo skin fibroblasts.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Interleukin-1 and interleukin-6 differentially regulate the accumulation of newly synthesized extracellular matrix components and the cytokine release by developing chick embryo skin fibroblasts. 784 37

Re-epithelialization involves interactions between keratinocytes and the extracellular matrix upon which these cells move. It is hypothesized that keratinocytes are activated when wounded, and the resultant phenotypic change directs re-epithelialization. We have adapted organotypic cultures, in which oral gingival keratinocytes are fully differentiated, to study re-epithelialization following wounding. To elucidate keratinocyte behavior and phenotype during re-epithelialization, we have investigated this process in the presence and absence of the growth factor TGF-beta 1 and have monitored expression of MMP-1 (Type I collagenase) mRNA by in situ hybridization. In addition, we have followed proliferation and migration of wound keratinocytes by genetically marking these cells with a retroviral vector and by measuring their proliferative index. We found that keratinocytes grown without TGF-beta 1 were hyperproliferative in response to wounding, and re-epithelialization was complete by 24 h. However, 2.5 ng/mL TGF-beta 1 induced a transient delay in re-epithelialization, a reduction in proliferation, and fewer clusters of genetically marked cells. Keratinocytes expressed MMP-1 mRNA only when they covered the wounded surface, suggesting that the cells acquire a collagenolytic phenotype during re-epithelialization and that contact with different ECM components may modulate keratinocyte expression of MMP-1. We conclude that the phenotype of oral keratinocytes is altered during re-epithelialization in vitro and that this process is modulated by TGF-beta 1. Re-epithelialization occurs as keratinocytes are activated to move over the wound bed. Understanding the phenotype of wounded keratinocytes may facilitate treatment of chronic oral wounds and periodontal disease.
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PMID:Re-epithelialization of human oral keratinocytes in vitro. 867 2

Extracellular matrix metalloproteinases (MMPs) are activated in dilated cardiomyopathic (DCM) hearts [Tyagi et al. (1996): Mol Cell Biochem 155:13-21]. To examine whether the MMP activation is occurring at the gene expression level, we performed differential display mRNA analysis on tissue from six dilated cardiomyopathy (DCM) explanted and five normal human hearts. Specifically, we identified three genes to be induced and several other genes to be repressed following DCM. Southern blot analysis of isolated cDNA using a collagenase cDNA probe indicated that one of the genes induced during DCM was interstitial collagenase (MMP-1). Northern blot analysis using MMP-1 cDNA probe indicated that MMP-1 was induced three- to fourfold in the DCM heart as compared to normal tissue. To analyze posttranslational expression of MMP and tissue inhibitor of matrix metalloproteinase (TIMP) we performed immunoblot, immunoassay, and substrate zymographic assays. TIMP-1 and MMP-1 levels were 37 +/- 8 ng/mg and 9 +/- 2 ng/mg in normal tissue specimens (P < 0.01) and 2 +/- 1 ng/mg and 45 +/- 11 ng/mg in DCM tissue (P < 0.01), respectively. Zymographic analysis demonstrated lytic bands at 66 kDa and 54 kDa in DCM tissue as compared to one band at 66 kDa in normal tissue. Incubation of zymographic gel with metal chelator (phenanthroline) abolished both bands suggesting activation of neutral MMP in DCM heart tissue. TIMP-1 was repressed approximately twentyfold in DCM hearts when compared with normal heart tissue. In situ immunolabeling of MMP-1 indicated phenotypic differences in the fibroblast cells isolated from the DCM heart as compared to normal heart. These results suggest disruption in the balance of myopathic-fibroblast cell ECM-proteinase and antiproteinase in ECM remodeling which is followed by dilated cardiomyopathy.
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PMID:Differential gene expression of extracellular matrix components in dilated cardiomyopathy. 891 70

This study was performed to evaluate the role of human microenvironmental cells in the metabolism of AcSDKP, a physiological inhibitor of hematopoietic stem cells. Using long-term marrow cultures (LTMCs), whose medium already contained a baseline value of AcSDKP, we found after 2 weeks a net output in the culture supernatant indicating that release by cells from the adherent layer was superior to consumption of the peptide. Since human microenvironmental cells consist of macrophages and vascular smooth-muscle-like stromal cells we generated pure populations of macrophages (by culturing cord blood cells in the presence of granulomonocytic colony-stimulating factor) and of stromal cells (generated by stromal colonies). We found in supernatants of macrophage cultures a significantly (p < 0.01) increased level of AcSDKP (compared with value in medium) while in supernatants of stromal cell cultures the level was decreased. Cell content of angiotensin-converting enzyme (ACE) in stromal cells was higher than in macrophages, which suggests a degradation of AcSDKP by stromal cells because of their higher amount of ACE. Finally, we analyzed the content of AcSDKP in adherent layers of LTMCs (with or without extracellular matrix [ECM] components), macrophages, and stromal cells. We found levels of AcSDKP of 1.5 pMol per 106 cells in extracts from macrophages or from stromal cells. On the contrary, extracts from primary layers of LTMCs contained 3 times more AcSDKP; however, after treatment of primary layers by collagenase, AcSDKP level fell to 1 pMol per 10(6) cells. Immunofluorescence using an anti-AcSDKP monoclonal antibody showed an extracellular network in certain areas of LTMCs. This study shows that 1) macrophages synthesize and release in the supernatant AcSDKP, 2) stromal cells probably degrade the peptide via ACE, and 3) components of the ECM from LTMCs serve as a reservoir for the peptide. These results are reminiscent of what has been described for growth factors, produced by microenvironmental cells, and stored in the ECM in close vicinity to hematopoietic precursors.
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PMID:Production and consumption of the tetrapeptide AcSDKP, a negative regulator of hematopoietic stem cells, by hematopoietic microenvironmental cells. 901 14

Migration to the intima and other responses of M-SMC in the rat carotid artery and abdominal aorta after balloon injury were investigated in vivo. Migration occurred intensively between the second and fifth days after injury. About 80% of the cells were in the G1 and S phases of the cell cycle. The majority of the migrating cells were therefore simultaneously proliferating. Positive values of 42.3%, 48.9%, 44.4%, and 32.8% of the migrating cells on the fifth day in the carotid artery for PDGF-B, elastase III B, MMP-I, and MMP-9, were observed, respectively. Many of the cells expressed messages of PDGF-A and elastases II and III B by in situ hybridization. Fine structures of the migrating cells were characterized as a synthetic phenotype of the smooth muscle cell with reduced attachment to their surrounding ECM. A biphasic proliferative response of the M-SMC appeared on the second and fifth days. Migration occurred correspondingly in the proliferative period. The populations of M-SMC positive in immunostainings for PDGFs, their receptors, elastase III B, and MMP-1 and MMP-9 also increased biphasically, around 12 h and five days after the injury. The results of these studies suggest that the migrating cells were proliferative and synthesizing PDGFs, elastases, and collagenases.
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PMID:Migration of medial smooth muscle cells to the intima after balloon injury. 918 23


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