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)

Altered degradation of extracellular matrix has been implicated in the pathogenesis of hepatic fibrosis. We investigated levels and cellular sites of gene expression of two major collagen-degrading enzymes, matrix-metalloproteinase (MMP)-1 (fibroblast type-interstitial collagenase) and MMP-2 (72-kd gelatinase, type IV collagenase) in five normal and 18 fibrotic human livers as well as in cultured human hepatic fat-storing cells by Northern blot analysis and in situ hybridization. Fat-storing cells expressed both MMP-1 and MMP-2 RNA in vitro. In vivo, MMP-1 was undetectable in mesenchymal and parenchymal cells of all liver specimens, whereas MMP-2 transcripts were expressed in all livers by vimentin-positive, CD68-negative mesenchymal cells. Mesenchymal cells of all fibrotic livers displayed high transcript levels of transforming growth factor-beta 1, which is known to modulate MMP expression. Along with de novo fibrogenesis and possibly influenced by transforming growth factor-beta 1, expression of MMP-2 in the absence of MMP-1 expression may be responsible for the quantitative and qualitative changes of extracellular matrix observed in chronic liver disease.
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PMID:Differential expression of matrix-metalloproteinase-1 and -2 genes in normal and fibrotic human liver. 812 38

Overexpression of the multifunctional growth factor transforming growth factor-beta 1 (TGF beta 1) has been connected to numerous diseases in human. TGF beta 1 expression is largely governed by three AP-1 binding sites located in two different promoters of this gene. We have examined the ability of retinoid receptors to inhibit the activity of the two promoters (especially the promoter 1) by cotransfection assays in the hepatocellular carcinoma cell line HepG2. When the TGF beta 1 promoter activity is induced by 12-O-tetradecanoyl phorbol13-acetate (an activator of AP-1-controlled gene transcription), this activity can be strongly repressed by retinoic acid receptor-alpha (RAR alpha), RAR beta, or retinoid X receptor-alpha (RXR alpha) as well as other members of the nuclear receptor family. Repression was hormone dependent and a function of receptor concentration. Heterodimerization of RAR alpha or RAR beta with RXR alpha did not modify the inhibition activities of these receptors, indicating that heterodimer formation is not required for antagonizing of AP-1 activity. On further examining the anti-AP-1 activity of RXR alpha we observed that three different AP-1-controlled promoters (TGF beta 1, collagenase, and cFos) can be inhibited. Using gel shift assays, we demonstrated that RXR alpha inhibits Jun and Fos DNA binding and that 9-cis RA enhances this inhibition, suggesting that a mechanism involving direct protein-protein interaction between RXR and AP-1 components mediates the inhibitory effect observed in vivo. Transfection analyses with RXR alpha point mutations revealed that residues L422, C432, and, to a lesser extent, residues L418 and L430, are involved in ligand-induced anti-AP1 activity of RXR alpha in vivo. Thus both types of retinoid receptors can inhibit AP-1-activated promoters, including the TGF beta 1 gene promoter, via a mechanism that involves protein-protein interaction.
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PMID:Retinoic acid receptors and retinoid X receptor-alpha down-regulate the transforming growth factor-beta 1 promoter by antagonizing AP-1 activity. 826 64

1. Pig synovial fibroblasts in culture were studied to determine if they were an easily reproducible model system for studying the actions of cytokines and growth factors on human synovial cells. The biochemical analyses were conducted by activity assays, enzymography and Northern blot. 2. Human recombinant interleukin-1 alpha, basic fibroblast growth factor and transforming growth factor-beta 1 were studied in combinations because of their known involvement in controlling tissue remodelling. 3. The response of pig fibroblasts to these agents, in terms of the expression of matrix metalloproteinases (collagenase, gelatinase and stromelysin) and their inhibitors (TIMPs), show that they behave similarly enough to human cells for use when supplies of human primary cells are unavailable.
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PMID:The expression of matrix metalloproteinases and their inhibitors by pig synovial cells and their regulation by combinations of cytokines and growth factors. 828 64

It is known that the mammalian ovary possesses a complete interleukin-1 (IL-1) system replete with ligands, receptors, and a receptor antagonist. To further assess the hypothesis that IL-1 may play an intermediary role in gonadotropin-triggered ovulation, we have set out to determine whether IL-1 is capable of promoting ovarian collagenase biosynthesis, an established component of the ovulatory cascade. Untreated cultured whole ovarian dispersates from immature (25 day old) rats constitutively elaborated several collagenolytic species as assessed in a gelatin matrix. A major 72 kilodalton (kDa) gelatinase (GL) was particularly apparent. Treatment with IL-1 beta produced selective dose- and cell density-dependent increments in the accumulation of a 92-kDa GL species. Administration of an IL-1 receptor antagonist neutralized the IL-1-induced stimulation of the 92-kDa GL in a dose-dependent fashion thereby supporting the presumption that the IL-1 effect is receptor mediated. Studies of comparable cellular densities of granulosa or enriched theca-interstitial cultures demonstrated the IL-1 induced 92-kDa GL to be highly expressed in the enriched theca-interstitial but not in the isolated granulosa cell preparations. Treatment with transforming growth factor-beta 1, a putative regulator of IL-1 action, significantly attenuated IL-1-induced 92-kDa GL accumulation thereby suggesting a potential regulatory paracrine/autocrine role for this agent in ovarian gelatinase economy. Initial characterization revealed the 92-kDa GL species to be a metalloproteinase present in its proenzyme zymogenic form. Taken together, our present findings reveal the ovarian expression of a constitutive 72-kDa GL and of an IL-1-stimulated 92-kDa GL the accumulation of which is particularly marked in enriched theca-interstitial preparations. These observations, along with the demonstration of the gonadotropin-dependent preovulatory induction of ovarian IL-1 gene expression, provide strong indirect support for the view that IL-1 may be the centerpiece of an intraovarian regulatory loop concerned with the promotion of the ovulatory cascade.
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PMID:Cytokine-mediated regulation of rat ovarian function: interleukin-1 stimulates the accumulation of a 92-kilodalton gelatinase. 838 88

The balance between the activities of matrix metalloproteinases (MMPs) and the tissue inhibitors of metalloproteinases (TIMPs) is an important control point in tissue remodeling. Previous studies have demonstrated elevated expression of the MMPs collagenase and stromelysin-1 by aged human diploid fibroblasts compared to early-passage cultures. We show here that aging cells display an altered response to transforming growth factor-beta 1 (TGF beta 1) that selectively affects MMP mRNA expression. In both young and old cells, phorbol myristoyl-13 acetate (PMA) induced the expression of transcripts of collagenase, stromelysin-1, gelatinase-B, TIMP-1, and TIMP-3. In young cells, TGF beta 1 reciprocally modulated PMA-induced MMP and TIMP gene expression leading to reduced levels of transcripts for the MMPs and augmented accumulation of TIMP-1 and TIMP-3 mRNAs. However, repressing effects of TGF beta 1 on collagenase, stromelysin-1, and gelatinase-B RNA expression were not apparent in old cells, though induction of the TIMP genes was unimpaired. By electrophoretic mobility shift analysis the nuclear transcription factors AP1 and serum response factor (SRF) showed reduced levels of DNA binding activities in old fibroblasts compared to young cells. A probe for the TGF beta-inhibitory element (TIE) gave equivalent levels of complexes with nuclear extracts from both types of cells, though of different mobilities. We conclude that the effects of TGF beta 1 on MMP and TIMP gene expression involve different cellular intermediaries, and suggest that altered composition or modification of TIE binding factors in aging cells may underlie the failure of TGF beta 1-mediated transcription repression. This mechanism may contribute to elevated constitutive expression of MMPs in old cells and to the connective tissue deterioration that accompanies the aging process.
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PMID:Differential effects of transforming growth factor-beta 1 on the expression of matrix metalloproteinases and tissue inhibitors of metalloproteinases in young and old human fibroblasts. 870 90

In order to elucidate collagen metabolism in hepatocellular carcinoma (HCC) tissue, we compared levels of different potential markers of collagen metabolism and plasma transforming growth factor-beta 1 in patients with HCC and in patients with liver cirrhosis. Serum levels of prolyl hydroxylase and the tissue inhibitor of metalloproteinase-1 in patients with HCC were significantly higher than those in patients with liver cirrhosis and increased with the size of the HCC tumour, whereas the serum levels of procollagen type III propeptide and type IV collagen 7S domain were similar in the two groups. In HCC, the increased plasma transforming growth factor-beta 1 levels were closely correlated with serum levels of prolyl hydroxylase and the tissue inhibitor of metalloproteinase-1. These findings suggest that, in HCC tissue, the intracellular biosynthesis of collagen is enhanced, whereas the secretion of procollagen is disturbed and the degradation of collagen is suppressed by the excess production of the tissue inhibitor of metalloproteinase-1. The results also suggest that plasma transforming growth factor-beta 1 plays an important role in the altered metabolism of collagen in HCC.
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PMID:Serum markers for fibrosis and plasma transforming growth factor-beta 1 in patients with hepatocellular carcinoma in comparison with patients with liver cirrhosis. 874 16

Angiotensin-converting enzyme (ACE) inhibitors have been shown to minimize fibrosis of the kidney tubulointerstitium in several diseases. In addition to lowering angiotensin II levels, ACE inhibitors can increase kinin levels and subsequently increase nitric oxide formation. To determine whether nitric oxide generation is a component of the beneficial effect of ACE inhibitors on renal fibrosis, enalapril, enalapril plus NG-nitro-L-arginine methyl ester (L-NAME) or L-arginine was administered to rats that had undergone unilateral ureteral obstruction (UUO). Ureteral obstruction caused significant increases in interstitial volume, monocyte macrophage infiltration, interstitial collagen IV and alpha-smooth muscle actin expression, transforming growth factor-beta 1 mRNA, collagen IV mRNA, and tissue inhibitor of metalloproteinase-1 mRNA. Enalapril treatment significantly blunted the increase in all parameters during UUO. Cotreatment of the animals with enalapril and L-NAME reversed the beneficial effect of enalapril in the obstructed kidney for all parameters. Treatment of animals with UUO with L-arginine significantly blunted the increase in all parameters except for transforming growth factor-beta 1 mRNA expression. In the enalapril- plus-L-NAME-treated animals, there were modest but significant increases in monocyte/macrophage infiltration of the interstitium and glomerulus, and collagen IV and alpha-smooth muscle actin expression in the interstitium of the contralateral unobstructed kidney. The urine nitrite concentration was significantly increased by either enalapril or L-arginine treatment, whereas L-NAME significantly reduced urine nitrite concentration. These results suggest that treatment modalities that increase nitric oxide formation have a beneficial effect on the progression of cellular and molecular parameters of tubulointerstitial fibrosis caused by obstruction of the ureter.
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PMID:Nitric oxide generation ameliorates the tubulointerstitial fibrosis of obstructive nephropathy. 891 81

Cytoskeleton not only controls cell morphology but also regulates cell growth, migration, differentiation, and gene expression, events which are fundamental to embryogenesis, carcinogenesis, and wound healing. We have recently reported that reorganization of cytoskeleton induces expression of mRNA for transforming growth factor-beta 1 (TGF-beta 1), collagenase, and tissue inhibitor of metalloproteinase-I (TIMP-I) in dermal fibroblasts. In this report we have examined the role of gene transcription in this induction. As judged by nuclear run-on assay, trypsin, EGTA (ethylene glycol-bis (beta-aminoethyl ether) N, N, N', N', tetra-acetic acid), or cytochalasin C (Chs) increased the rate of transcription of the TGF-beta 1 gene by 2.0, 2.7, and 1.6 fold, respectively, and of the collagenase gene by 5.3, 6.2, and 3.3 fold. The rate of transcription of the TIMP-I gene was increased by trypsin (4.3 fold) or EGTA (3.8 fold) but unaffected by Chs. Cytochalasin induced an increase in the rate of transcription of procollagen I (alpha 1), procollagen I (alpha 2), and fibronectin genes by 1.4, 1.5, and 1.9 fold respectively, while trypsinization or EGTA treatment had no or little effects on these gene. Since transcription of the TGF-beta 1 gene is believed to be largely governed by the activating protein 1 (AP1) complex, we also examined the expression of mRNA for c-fos and c-jun protoon-coproteins. Trypsinization induced rapid (within 30 min) and transient expression of c-fos mRNA. A 2.4 fold increase in c-jun mRNA was apparent after 4 hr and persisted for at least 24 hr. Actinomycin D (Act D) suppressed the induction of TGF-beta 1 mRNA by Chs but had less effect on the TGF-beta 1 mRNA in trypsinized cells which had been replated for 4 hr, suggesting that the half life of TGF-beta 1 mRNA is reduced in cells with a disassembled cytoskeleton. Simultaneous treatment with Chs and cycloheximide (Cxm) resulted in a superinduction of TGF-beta 1 mRNA by 88 +/- 23% (n = 4, P < 0.05), which was abrogated by preexposure to Act D. In contrast, the induction of collagenase mRNA by Chs was totally blocked by Cxm, indicating that the Cxm-mediated superinduction is selective and that protein synthesis is required for induction of this mRNA. Our results suggest that the activities of genes for proteins involved in the structure (Type I collagen and fibronectin), turnover (collagenase and TIMP-1) and regulation (TGF-beta 1) of extracellular matrix (ECM), are all governed at least in part by the status of the cytoskeleton. Since the cytoskeleton is reorganized during cell division, migration, and differentiation, these results may have implications for the regulation of ECM during such processes as embryogenesis, carcinogenesis, and wound healing.
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PMID:Cytoskeleton regulates expression of genes for transforming growth factor-beta 1 and extracellular matrix proteins in dermal fibroblasts. 925 40

1. Pentoxifylline (PTF) may act as a potential antifibrogenic agent by inhibiting cell proliferation and/or collagen deposition in cell type(s) responsible for the accumulation of extracellular matrix. The aim of the present study was to investigate at which level PTF may affect synthesis and degradation of type I collagen in human hepatic stellate cells (HSCs), a key source of connective tissue in fibrotic liver. 2. Procollagen type I synthesis and release were evaluated in cells maintained in serum free/insulin free medium for 48 h and then stimulated with transforming growth factor-beta 1 (TGF-beta 1) for different time periods in the presence or absence of PTF. TGF-beta 1 caused an upregulation of procollagen I mRNA levels with a peak increase after 3-6 h of stimulation. This effect was followed by an increase in both the cell associated and the extracellular levels of the corresponding protein, with a peak effect at 9-12 h after the addition of TGF-beta 1. Co-incubation with PTF slightly but consistently reduced basal as well as stimulated procollagen I mRNA levels, with negligible effects on the cell-associated expression of the corresponding protein. Conversely, PTF dose-dependently reduced procollagen type I levels detected in supernatants from unstimulated and stimulated cells. 3. Pulse-chase experiments employing L-[3H]-proline revealed that PTF was able to induce significantly the degradation of procollagen, mainly in the extracellular compartment. We next analysed the effect of PTF on the major pathway involved in type I collagen degradation. PTF did not affect the expression of metalloproteinase 1 (MMP-1) mRNA both in basal and stimulated conditions, whereas it markedly reduced the expression of tissue inhibitor of metalloproteinase 1 (TIMP-1) mRNA. Accordingly incubation with PTF increased the levels of 'activated MMP-1' in cell supernatants in both basal and stimulated conditions. 4. These results suggest that the antifibrogenic action of PTF on human HSCs is mainly mediated by extracellular collagen degradation rather than by a reduction of collagen synthesis.
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PMID:Effect of pentoxifylline on the degradation of procollagen type I produced by human hepatic stellate cells in response to transforming growth factor-beta 1. 940 68

Little is known about the pathogenesis of fibrosis in chronic pancreatitis. To reach a better understanding of this problem, we investigated the immunolocalizations of type IV collagen (Col-IV) and laminin around pancreatic ducts, and those of matrix metalloproteinase-2,9 (MMP-2,9), tissue inhibitors of metalloproteinase-1,2), and transforming growth factor-beta 1 (TGF beta 1) at the ductal epithelia in chronic pancreatitis. This study included 20 surgical specimens of fibrotic pancreas from patients with chronic pancreatitis and five normal samples from autopsy cases. Immunostaining was performed by the streptavidin-biotin method after antigen retrieval. We evaluated the staining patterns and the percentage of positive cells of each antigen. In chronic pancreatitis, the immunostainings of Col-IV and laminin along the basement membrane (BM) of pancreatic ducts were disrupted in 11 (55%) of 20 and eight (40%) of 20, respectively, whereas no disruption was detected in normal pancreas. Positive immunostainings for MMP-2, MMP-9, TIMP-1, and TIMF-2 in ductal epithelia were 15 (75%) of 20, five (25%) of 20, four (20%) of 20, and 10 (50%) of 20, respectively, whereas no immunostaining was seen in normal pancreas. The staining intensity of MMP-2 in ductal epithelia was associated with the staining intensity of Col-IV around the pancreatic ducts. Also, the staining intensity of MMP-2 was progressively increased in proportion to the staining intensity of TGF beta 1. These findings suggest that TGF beta 1 induced in pancreatic duct cells also induced MMP-2 in an autocrine or paracrine manner, and that this MMP-2 decomposed Col-IV of the BM of pancreatic ducts in chronic pancreatitis.
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PMID:Immunohistochemical study of transforming growth factor-beta 1, matrix metalloproteinase-2,9, tissue inhibitors of metalloproteinase-1,2, and basement membrane components at pancreatic ducts in chronic pancreatitis. 982 Nov 84


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