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:3.4.24.3 (collagenase)
18,340 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Immortalized human chondrocytes were established by transfection of primary cultures of juvenile costal chondrocytes with vectors encoding simian virus 40 large T antigen and selection in suspension culture over agarose. Stable cell lines were generated that exhibited chondrocyte morphology, continuous proliferative capacity (> 80 passages) in monolayer culture in serum-containing medium, and expression of mRNAs encoding chondrocyte-specific collagens II, IX, and XI and proteoglycans in an insulin-containing serum substitute. They did not express type X collagen or versican mRNA. These cells synthesized and secreted extracellular matrix molecules that were reactive with monoclonal antibodies against type II collagen, large proteoglycan (PG-H, aggrecan), and chondroitin-4- and chondroitin-6-sulfate. Interleukin-1 beta (IL-1 beta) decreased the levels of type II collagen mRNA and increased the levels of mRNAs for collagenase, stromelysin, and immediate early genes (egr-1, c-fos, c-jun, and jun-B). These cell lines also expressed reporter gene constructs containing regulatory sequences (-577/+3,428 bp) of the type II collagen gene (COL2A1) in transient transfection experiments, and IL-1 beta suppressed this expression by 50-80%. These results show that immortalized human chondrocytes displaying cartilage-specific modulation by IL-1 beta can be used as a model for studying normal and pathological repair mechanisms.
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PMID:Interleukin-1 beta-modulated gene expression in immortalized human chondrocytes. 798 69

The c-fos proto-oncogene is believed to play a pivotal role in transducing growth factor-mediated signals from the extracellular milieu into the nucleus. c-fos protein dimerizes with c-jun and related proteins and mediates transcription via AP-1 sites. Using c-fos-deficient mice generated through gene knockout techniques, we derived 3T3-type cell lines from primary embryonic fibroblasts. The c-fos-deficient cells grow normally under optimal culture conditions and show only a slight reduction in growth rate in low serum culture compared with control cells. They also express mRNA for most of the Fos and Jun family members at normal levels. The overall levels of AP-1 DNA binding activity are normal and several genes (c-jun, MCP1, metallothionein) known to contain functional AP-1 sites are expressed normally in the c-fos-deficient and control cells. In contrast, mRNA for the metalloproteases stromelysin (MMP-3) and type I collagenase (MMP-1), which are often induced by oncogenes and growth factors and have been implicated in tumor invasiveness, cannot be induced by epidermal growth factor or platelet-derived growth factor in c-fos-deficient cells. Transformation of mutant cells with polyoma middle T oncogene essentially restores wild-type levels of stromelysin expression, while transformation with v-src leads to only a weak induction of the metalloprotease. These results clearly demonstrate that some AP-1-dependent genes require c-fos for full expression while others do not; oncogenes may activate expression of metalloproteases via either fos-dependent or fos-independent mechanisms. These results also imply that c-fos may play an important regulatory role in the invasive behavior of malignant tumors, independent of any role this proto-oncogene might play in cell growth per se.
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PMID:Targeted disruption of the c-fos gene demonstrates c-fos-dependent and -independent pathways for gene expression stimulated by growth factors or oncogenes. 803 3

Matrix metalloproteinases are secreted enzymes important in inflammation and tumor invasion. Earlier, we demonstrated that in normal human FS-4 fibroblasts, collagenase and stromelysin mRNA levels are increased not only after treatment with known matrix metalloproteinase inducers such as tumor necrosis factor (TNF), interleukin-1, and 12-O-tetradecanoylphorbol-13-acetate, but also with interferon-beta (IFN-beta). In this study, we compared the regulation of these matrix metalloproteinase genes by TNF and IFN-beta. We show that both TNF and IFN-beta increase steady-state levels of collagenase and stromelysin mRNAs with similar slow kinetics. The glucocorticoid dexamethasone blocked matrix metalloproteinase induction by both cytokines. The protein synthesis inhibitor cycloheximide inhibited collagenase mRNA induction by TNF or IFN-beta, suggesting that induction by both agents is indirect. Consistent with these observations, both TNF and IFN-beta increased c-fos and c-jun mRNA levels. Furthermore, treatment with TNF or IFN-beta increased the transcriptional activity of activator protein-1-responsive chloramphenicol acetyltransferase reporter gene constructs, including a native collagenase promoter-driven chloramphenicol acetyltransferase construct. These findings show that regulation of matrix metalloproteinase gene expression by both TNF and IFN-beta involves the transcription factor activator protein-1 and demonstrate a novel indirect mechanism of type I IFN-induced gene expression.
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PMID:Interferon-beta induces metalloproteinase mRNA expression in human fibroblasts. Role of activator protein-1. 806 4

Previous investigations have shown that culture of freshly isolated hepatocytes under conventional conditions, i.e., on dried rat tail collagen in the presence of growth factors, facilitates cell growth but also causes an extensive down-regulation of most liver-specific functions. This dedifferentiation process can be prevented if the cells are cultured on a reconstituted basement membrane gel matrix derived from the Englebreth-Holm-Swarm mouse sarcoma tumor (EHS gel). To gain insight into the mechanisms regulating this response to extracellular matrix, we are analyzing the activities of two families of transcription factors, C/EBP and AP-1, which control the transcription of hepatic and growth-responsive genes, respectively. We demonstrate that isolation of hepatocytes from the normal quiescent rat liver by collagenase perfusion activates the immediate-early growth response program, as indicated by increased expression of c-jun, junB, c-fos, and c-myc mRNAs. Adhesion of these activated cells to dried rat tail collagen augments the elevated levels of these mRNAs for the initial 1 to 2 h postplating; junB and c-myc mRNA levels then drop steeply, with junB returning to normal quiescence and the c-myc level remaining slightly elevated during the 3-day culture period. Levels of c-jun mRNA and AP-1 DNA binding activity, however, remain elevated from the outset, while C/EBP alpha mRNA expression is down-regulated, resulting in a decrease in the steady-state levels of the 42- and 30-kDa C/EBP alpha polypeptides and C/EBP alpha DNA binding activity. In contrast, C/EBP beta mRNA production remains at near-normal hepatic levels for 5 to 8 days of culture, although its DNA binding activity decreases severalfold during this time. Adhesion of hepatocytes to the EHS gel for the same period of time dramatically alters this program: it arrests growth and inhibits AP-1 DNA binding activity and the expression of c-jun, junB, and c-myc mRNAs, but, in addition, it restores C/EBP alpha mRNA and protein as well as C/EBP alpha and C/EBP beta DNA binding activities to the abundant levels present in freshly isolated hepatocytes. These changes are not due merely to growth inhibition, because suppression of hepatocyte proliferation on collagen by epidermal growth factor starvation or addition of transforming growth factor beta does not inhibit AP-1 activity or restore C/EBP alpha DNA binding activity to normal hepatic levels. These data suggest that expression of the normal hepatic phenotype requires that hepatocytes exist in a G0 state of growth arrest, facilitated here by adhesion of cells to the EHS gel, in order to express high levels of hepatic transcription factors such as C/EBP alpha.
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PMID:Cell-extracellular matrix interactions can regulate the switch between growth and differentiation in rat hepatocytes: reciprocal expression of C/EBP alpha and immediate-early growth response transcription factors. 806 19

Using specific cDNAs isolated from mouse fibroblasts we determined tissue-specific expression of different matrix metalloproteinase genes: both stromelysin-1 and collagenase IV are highly expressed in heart and lung, whereas collagenase I is expressed most abundantly in skeletal muscle, kidney, and bone. High basal level expression of stromelysin-2 is found in heart and kidney. Like in man and rat, the expressions of collagenase I, stromelysin-1, and stromelysin-2 are regulated by the tumor promoter 12-O-tetradecanoyl-phorbol 13-acetate and by UV irradiation, but not by cAMP. In contrast, the expression of the 72-kDa collagenase IV is not affected by either stimuli. We and others have shown previously that under cell culture conditions, the regulation of human collagenase I is regulated by the transcription factor Fos/Jun (AP-1). Here we show that in c-fos transgenic mice transcription of collagenase I is induced in thymus, spleen, and, most dominantly, in bone upon overexpression of Fos. Neither collagenase IV nor stromelysin-1 or stromelysin-2 expression is affected by c-Fos. The sites of induced collagenase I expression correlate with the sites of Fos-induced long-term cellular alterations in transgenic mice including bone remodeling and T cell development. In fact, in the developing bone tumors strongly enhanced levels of collagenase I transcripts were detectable. These results identify collagenase I as a Fos-regulated gene in vivo and suggest a possible role for Fos/Jun heterodimers in establishing the pathological phenotype of c-fos transgenic mice.
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PMID:Phenotypic alterations in fos-transgenic mice correlate with changes in Fos/Jun-dependent collagenase type I expression. Regulation of mouse metalloproteinases by carcinogens, tumor promoters, cAMP, and Fos oncoprotein. 814 18

The proto-oncogene transcription factors Fos and Jun form a heterodimeric complex that binds to DNA and regulates expression of specific target genes. Continuous expression of c-fos causes transformation of cultured fibroblasts and induces osteogenic sarcoma in mice. To investigate the molecular basis of fos-mediated oncogenesis, we developed a conditional cell transformation system in which Fos expression was regulated by isopropyl-beta-D-thiogalactopyranoside (IPTG). Synthesis or repression of Fos in L1-3c-fos cells occurred rapidly, within 30 min, after the removal or addition of IPTG to the culture medium. However, there was a significant delay between the induction of Fos expression and the appearance of morphological transformation. No effect was observed after 12 h of Fos expression, partial transformation was detected after 24 h, and full transformation required approximately 3 days of continuous Fos expression. Similarly, the transformed cell morphology persisted for at least 2 days after repression of Fos, and a normal phenotype was observed only after 3 days. Fos-Jun complexes, capable of binding to AP-1 sequences, were present continuously during the delay in morphological transformation. Furthermore, increased expression of several candidate Fos target genes, including those encoding Fra-1, transin (stromelysin), collagenase, and ornithine decarboxylase, was detected shortly after Fos induction. The induction of morphological transformation was not dependent on the cell cycle, as it occurred in both cycling and noncycling cells. Thus, the Fos-Jun complexes present before L1-3c-fos cells become fully transformed are transcriptionally active. These complexes disappeared, and the Fos target genes were repressed at least 2 days prior to reversion. Our results suggest that cell transformation by Fos requires increased expression of a target gene(s) with a long-lived product(s) that must reach a critical level.
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PMID:Cell transformation by c-fos requires an extended period of expression and is independent of the cell cycle. 819 66

Matrixmetalloproteinases (MMP), such as type IV collagenases and interstitial collagenases, play an important role in tumor invasion and metastasis. And tissue inhibitor of metalloproteinases (TIMP) inhibit collagenolytic activity of these enzymes. We investigated the gene expressions of MMP-9 (92 kDa type IV collagenase), MMP-2 (72 kDa type IV collagenase), TIMP-1 and TIMP-2 in bladder cancers by Northern blot and slot blot hybridization. The mRNA levels of MMP-2, TIMP-1 and TIMP-2 increased in the cases with invasion and metastasis of bladder cancers. These findings suggest that MMP-2 acts as a regulator of the invasion and metastasis of bladder cancers. The MMP-2/TIMP-2 ratio increased as tumor invasion and metastasis progressed, suggesting that an imbalance in the MMP and TIMP ratio promote the invasion and metastasis of bladder cancers. And we also investigated the gene expressions of c-fos that activate the collagenase genes, and there was a correlation between c-fos and MMP-2 in gene expressions. It is suggested that fos gene may play an important role for the invasion and metastasis in bladder cancers.
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PMID:[Gene expressions of type IV collagenase and tissue inhibitor of metalloproteinases (TIMP) in human bladder cancers]. 832 Aug 89

Platelet-activating factor (PAF), a potent lipid mediator involved in inflammatory and immune responses, accumulates rapidly in response to injury in a variety of tissues, including the corneal epithelium. However, the precise role of this compound in the cascade of events following insult has not been defined. Here we examined the effect of PAF on gene expression in the epithelial cells of rabbit corneas in organ culture. We found that incubation with 100 nM methylcarbamoyl PAF, a nonhydrolyzable analog of PAF, produced rapid transient 2.8- and 3.5-fold increases in the expression of c-fos and c-jun, respectively, at 1 hr, followed by increased expression of the collagenase type I gene beginning at 3 hr and peaking at 14-fold by 8 hr. Addition of the protein-synthesis-inhibitor cycloheximide superinduced c-fos and c-jun, strongly potentiating the PAF effect, but inhibited the induction of collagenase type I expression, suggesting the existence of a transcriptional factor linking the two events. BN-50730, a selective antagonist of intracellular PAF-binding sites, blocked the expression of the immediate-early genes as well as the increase in collagenase type I mRNA. Our results suggest that one of the functions of PAF may be to enhance the breakdown of the extracellular matrix as a part of the remodeling process during corneal wound healing after injury. Pathologically, a PAF-induced overproduction of collagenase may be a factor in the development of corneal ulcers, as well as other pathophysiological conditions such as cartilage destruction in arthritis. If so, inhibitors of this signal-transduction pathway may be useful as tools for further investigation and, eventually, as therapeutic agents to treat such disorders.
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PMID:Platelet-activating factor induces collagenase expression in corneal epithelial cells. 837 47

Newborn rat brain astrocytes cultured in vitro in a chemically defined medium are shown to secrete enhanced levels of nerve growth factor (NGF) when they are exposed to various types of proteases. Proteolytic enzymes such as alpha-thrombin or collagenase induce a continuous, dose-dependent enhancement of the levels of cell-secreted NGF. Incubation of astrocytes for a 24-h period with 300 ng/ml of alpha-thrombin (approximately 9 nM, or 1 U/ml) results in an increase of the levels of cell-secreted NGF by a factor of three- to fourfold, and at doses 10 times higher, stimulation by a factor of up to four- to fivefold was observed. This phenomenon reflects an enhancement of the cellular pool of NGF mRNA, already noticeable after 3 h of treatment, which is preceded by a temporary activation of protooncogenes encoding transcription factors of the AP-1 family, such as c-fos, c-jun or junB. Trypsin, plasmin, alpha-chymotrypsin, or elastase also enhanced, to different extents, the levels of cell-secreted NGF. However, unlike alpha-thrombin or collagenase, these enzymes cause, above a critical concentration, an extensive cell detachment from the solid support, and this is accompanied by a decrease of their activity on the production of NGF, so that their dose-response curves are bell shaped. Stimulation was maximal at those concentrations that cause a limited loosening of the cell-substratum interactions, as evidenced by a retraction of some cell processes after 24 h of treatment. Studies of the effect of alpha-thrombin indicate that the proteolytic activity itself is required to enhance the production of NGF by astrocytes. Inactivation of alpha-thrombin with D-phenyl-alanyl-L-propyl-L-arginine chloromethyl ketone, phenylmethylsulfonyl fluoride, antithrombin III, or hirudin results in a marked decrease of the stimulatory effect. Furthermore, the prolonged presence of alpha-thrombin is required to elicit a maximal effect on the levels of extracellular NGF, which was observed after 48 h of treatment. It is known that some effects of alpha-thrombin require binding to the cell surface. We found that gamma-thrombin, which still has some proteolytic activity but has lost its ability to bind to the cell surface, is almost as potent as alpha-thrombin in promoting the release of NGF. It is concluded that the effect of thrombin on NGF synthesis is essentially mediated by its proteolytic activity.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Enhancement of the synthesis and secretion of nerve growth factor in primary cultures of glial cells by proteases: a possible involvement of thrombin. 843 76

We have investigated the effect of electroporation on the expression of collagen alpha 1(I), collagenase, c-fos and c-jun genes in human dermal fibroblasts (HDF), human smooth muscle cells (HSMC) and HeLa cells. Collagenase and collagen mRNA levels were respectively increased and decreased in a voltage-dependent manner in HDF harvested 2 days after a sham electroporation. These effects were still observed 10 days after electroporation. Similar effects occurred in electroporated HSMC. Neither collagen nor collagenase mRNAs were detected in control or electroporated HeLa cells. c-fos and c-jun mRNA levels were also increased in electroporated HDF, HSMC and HeLa cells harvested 1 h after plating. This suggests that factor AP1 (fos/jun) could mediate the up-regulation of collagenase expression in electroporated HDF and HSMC. When electroporation of HDF was performed in the presence of H7, an inhibitor of protein kinase C, no increase in collagenase mRNA level was observed, suggesting that protein kinase C might be involved in the transduction of the effect. All the effects reported were also suppressed when cells were electroporated in a medium containing EGTA, suggesting that Ca2+ might mediate the transduction of this effect.
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PMID:Modulation of expression of endogenous collagenase and collagen genes by electroporation: possible involvement of Ca2+ and protein kinase C. 843 82


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