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

---

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

The activity of type I 5'-deiodinase (5'DI) is known to correlate with thyroid status; it is high in hyperthyroidism and low in hypothyroidism. Recently, it was shown that the increased activity of type I 5'DI in hyperthyroidism is associated with an increase in enzyme contents as well as its mRNA in liver. However, it remains unknown whether thyroid hormone directly regulates the expression of 5'DI mRNA in hepatocytes. In this study, the direct actions of thyroid hormone as well as rT3 and dexamethasone on type I 5'DI mRNA were investigated using primary cultures of rat hepatocytes. Hepatocytes were prepared from euthyroid rats by collagenase perfusion and plated either on collagen-coated dishes for conventional monolayer cultures or on positively charged dishes for spheroid cultures. After hormonal treatments, the levels of mRNAs for type I 5'DI and albumin were determined by Northern blotting. In spheroid cultures, T3 increased type I 5'DI mRNA in a dose- and time-dependent manner, whereas the albumin mRNA level was not altered. A lesser effect was observed in hepatocytes cultured as monolayers. The T3-induced increase in 5'DI mRNA was not inhibited by pretreatment with cycloheximide, indicating that the effect of thyroid hormone on 5'DI mRNA is direct, not requiring de novo protein synthesis. rT3 did not affect the levels in type I 5'DI mRNA increased by T3. On the other hand, dexamethasone alone increased 5'DI mRNA and, when added together with T3, had a synergistic effect. In contrast to T3, dexamethasone increased albumin mRNA. Dexamethasone-induced increases in mRNAs for 5'DI and albumin were inhibited by pretreatment of cycloheximide. The present study indicated that T3 increases 5'DI mRNA through a direct action on its gene, whereas the effect of dexamethasone requires de novo synthesis of a protein factor(s).
...
PMID:Effects of thyroid and glucocorticoid hormones on the level of messenger ribonucleic acid for iodothyronine type I 5'-deiodinase in rat primary hepatocyte cultures grown as spheroids. 824 26

Rat mucosal keratinocytes serially propagated under permanently serum-free conditions responded to interleukin (IL)-1 beta/IL-alpha and to transforming growth factor (TGF)-alpha/epidermal growth factor (EGF) (as well as to 12-O-tetradecanoylphorbol-13-acetate (TPA)) by upregulation of M(r) 95,000 gelatinase (MMP-9) (M(r) 95K GL) and fibroblast-type collagenase (MMP-1) (FIB-CL), whereas control cells expressed barely detectable levels of either of these enzymes. The cells secreted 8-10 micrograms/10(6) cells/day (M(r) 95K GL) and 2-3 micrograms/10(6) cells/day (FIB-CL) of enzyme protein for at least 24 h when maximally induced. This level was attained only after a 24-h lag period, and the earliest emergence of enzyme protein in the culture medium required 10-14 h. IL-1 beta was by far the most potent cytokine with maximal effect already at 10(-10) M, whereas IL-1 alpha, TGF-alpha, and EGF required 20-100-fold higher concentrations. Pretreatment of the cells with TPA (10(-7) M) abolished the subsequent response to IL-1 beta, TGF-alpha, and EGF and at the same time resulted in > 90% reduction of cytosolic protein kinase C activity. Surprisingly, staurosporine, a potent kinase inhibitor, not only failed to block growth factor/cytokine responses but itself stimulated expression of the enzymes at a magnitude comparable to TPA. The inducing effect of TGF-alpha/EGF was down-regulated by 70-85% by 10(-7) M dexamethasone. Dexamethasone was less effective in ablating the IL-1 beta response yielding 60% reduction M(r) 95K GL and little or no reduction of FIB-CL. Dexamethasone also failed to block the TPA response.
...
PMID:Interleukin-1 beta and transforming growth factor-alpha/epidermal growth factor induce expression of M(r) 95,000 type IV collagenase/gelatinase and interstitial fibroblast-type collagenase by rat mucosal keratinocytes. 839 30

We have previously documented that glucocorticoids suppress the proliferation of BDS1 hepatoma cells, a rat epithelial tumor cell line derived from minimal deviation Reuber H35 hepatoma cells. Flow cytometry demonstrated that, after treatment with the synthetic glucocorticoid dexamethasone, the growth of an asynchronous population of BDS1 cells was arrested within one cell cycle which resulted in an accumulation of cells with a G1-G0-like DNA content. Consistent with a glucocorticoid-induced block early in the G1 phase of the cell cycle, propidium iodide flow cytometry revealed that addition of dexamethasone up to 2 h after release from contact inhibition prevented BDS1 hepatoma cells from entering S phase, whereas dexamethasone treatment after 2 h had no effect on the entry of cells into S phase. Moreover, dexamethasone treatment did not prevent BDS1 cells from entering S phase after release from synchronization at the G1-S boundary by a double thymidine block. Analysis of DNA content, [3H]-thymidine incorporation, and autoradiography of [3H]-thymidine-labeled nuclei revealed that, after release from dexamethasone, BDS1 cells synchronously reinitiated cell cycle progression and entered S phase 8 h after hormone withdrawal. Northern blot analysis demonstrated that the level of transcripts encoding the G1 marker genes CYL-1 and CYL-2 G1 cyclins peaked 4 h after dexamethasone withdrawal. Dexamethasone induced a 20-fold increase in the level of c-jun mRNA which was reversed after hormone withdrawal, whereas expression of c-fos transcripts remained at a low level during the time course of hormone treatment and withdrawal. Transient transfections with a collagenase-chloramphenicol acetyltransferase reporter gene showed that dexamethasone inhibited 12-O-tetradecanoylphorbol-13-acetate-inducible, but not basal, AP-1 transcription factor activity. Our results demonstrate that glucocorticoids reversibly induce an early G1 block in cell cycle progression of an epithelial tumor cell line that occurs with a coordinate elevation in the expression of c-jun transcripts.
...
PMID:Glucocorticoids reversibly arrest rat hepatoma cell growth by inducing an early G1 block in cell cycle progression. 846 59

The process of mineralization in cells prepared either by neutral protease digestion (Pro I) or by collagenase digestion (fifth cycle, Col V) from fetal rat mandible was studied in vitro. Alkaline phosphatase (ALPase) activity of cells in Pro I was low on day 3, increased rapidly from day 8, and reached a maximum on day 16, whereas that in Col V was high on day 2, then declined and thereafter elevated to reach a maximum on day 13. Both cell populations synthesized type I collagen in cell matrix and medium. Type III collagen was observed in cell matrix of Pro I on day 14 and 21. There was alpha 2 band of type V collagen in cell matrix of Pro I on day 21. Calcium deposition could be detected from day 14 in Pro I and from day 19 in Col V. The von Kossa-positive nodules were found on day 17 in Pro I and day 21 in Col V, respectively. The extracellular matrix in Pro I electron-microscopically consisted of well-banded collagen fibrils with a large number of calcified spherules. An elevation of ALPase activity, collagen synthesis, and mineral deposition occurred sequentially with a time lapse in Col V, and almost simultaneously in Pro I. The number of mineralized nodules was correlated with the density of plated cells in Pro I, but not in Col V. Dexamethasone caused an increase in the number of mineralized nodules in Pro I, but not in Col V, suggesting that Pro I contained osteoprogenitor cells.(ABSTRACT TRUNCATED AT 250 WORDS)
...
PMID:Differentiation and mineralization in osteogenic precursor cells derived from fetal rat mandibular bone. 850 75

Glucocorticoids have been shown to suppress collagen synthesis and gene expression by fibroblasts. However, little is known about their effects on fat-storing cells, the major matrix-producing cells in liver fibrosis. In this study we investigated the effect of dexamethasone on the extracellular matrix expression by cultured rat fat-storing cells. Fat-storing cells were isolated from male Wistar rats by collagenase/pronase digestion and purified by density gradient centrifugation. Fat-storing cells in early primary culture (3-day-old, representing a relatively quiescent phenotype) and in subculture (one passage, about 2-week-old, representing an activated phenotype) were treated with 10(-6) mol/L dexamethasone for messenger RNA (mRNA) study or with 10(-8) to 10(-6) mol/L dexamethasone for protein study. Expression of collagen type I, III, IV, fibronectin, and laminin was analyzed at the mRNA level by Northern hybridization, and at the protein level by metabolic labeling and immunoprecipitation. Dexamethasone had a variable effect on the expression of collagen alpha1(I) mRNA level. While a tendency for modest suppression was observed (5%-50%) in primary cells, the difference was not statistically significant. Variable response was observed in subcultured cells. Collagen alpha1(III) mRNA level showed a tendency for stimulation. Dexamethasone stimulated the expression of collagen alpha1 (IV), fibronectin, and laminin B1 mRNA levels by 1.4-, 2.4-, and 1.6-fold respectively, in primary fat-storing cells. Subcultured cells showed a similar response, but the magnitude of stimulation was more variable than that of primary cells. Unexpectedly, at the protein level dexamethasone had no effect on the expression of these proteins. Our results indicate that glucocorticoids do not possess a net suppressive effect on extracellular matrix synthesis by fat-storing cells. Beneficial effects of glucocorticoids may be attributable to other mechanisms of action, such as their anti-inflammatory effect.
...
PMID:Dexamethasone alters messenger RNA levels but not synthesis of collagens, fibronectin, or laminin by cultured rat fat-storing cells. 867 92

Matrix metalloproteinases (MMPs) have an important role in many biological processes, such as tumor metastasis, wound healing, and inflammation. The regulation of MMPs and their inhibitors is still not known in detail, and the aim of this study was to investigate the effects of dexamethasone on cultured oral benign and malignant cell lines. The expression of MMPs in culture was studied: in four gingival (GF) and one periodontal ligament (PLF) fibroblast cell lines; in six gingival keratinocyte (GK) cell lines; and in UNR (UNR-108, rat osteogenic sarcoma) and SCC (SCC-25, human tongue squamous cell carcinoma) cell lines. In the GFs, PLFs, and UNR cells, only MMP-2 (72 kDa gelatinase) was detected by gelatin zymography, while in most of the GK cell lines only MMP-9 (92 kDa gelatinase) was observed. In confluent SCC cultures, both MMP-2 and MMP-9 were found, while only MMP-2 was seen in rapidly growing SCC cells, demonstrating that cell proliferation influenced gelatinase expression in these cells, but not in the other cell lines studied. Dexamethasone at concentrations of 10(-5) mol/L and 10(-7) mol/L decreased the production of gelatinases in the GFs and PLFs, but not in the GKs, SCC, or UNR cells. The expression of mRNAs for matrix metalloproteinases (MMP-1 [interstitial collagenase] and MMP-2) and their inhibitors (TIMP-1 and TIMP-2) was also studied in the GFs by Northern hybridization. Dexamethasone markedly decreased the amount of MMP-2 mRNA in the GFs. The mRNA level of MMP-1 decreased even more in the same GFs. The mRNA levels for TIMP-1 and TIMP-2 were also decreased by dexamethasone in the GFs. Cell proliferation influenced the degree to which dexamethasone decreased these mRNA levels. The results indicate that glucocorticoids decrease the levels of MMPs and TIMPs in oral fibroblastic cells, whereas they do not appear to affect the production of gelatinases in either normal or malignant oral epithelial cell lines.
...
PMID:Effects of dexamethasone and cell proliferation on the expression of matrix metalloproteinases in human mucosal normal and malignant cells. 867 3

The objective of this study was to determine the acute effects of glucocorticoids on in vivo levels of bone collagen synthesis in neonatal mice. Mice were injected with vehicle or dexamethasone at the start of the experiment. At 22 h, mice were given a 10 microCi injection of [3H]proline. At 24 h, the mice were sacrificed and the incorporation of [3H]proline into collagenase-digestible CDP labeling) and noncollagen (NCP labeling) protein in calvariae were determined by digestion with bacterial collagenase. Calvarial RNA was analyzed for COL 1A1 and osteocalcin mRNA levels by Northern blotting. After 24 h, vehicle-treated mice showed a 9.8 +/- 1.0% weight gain while dexamethasone-treated mice (1 mg/kg) had a 7.4 +/- 0.8% weight loss. Dexamethasone (1 mg/kg) decreased CDP and NCP labeling in calvariae by 51 +/- 4% and 17 +/- 4%, respectively (13 experiments). The inhibitory effect on protein labeling was selective for collagen since dexamethasone decreased the percent collagen synthesis from 25.4 +/- 1.6% to 16.6 +/- 1.0% (13 experiments). Dexamethasone at 3 mg/kg also decreased CDP labeling and the percent collagen synthesis in calvariae. There was a 30% reduction in COL1A1 mRNA levels and a 67% decrease in osteocalcin mRNA levels. To determine the reversibility of the inhibition of collagen synthesis, mice were given a single injection of dexamethasone (1 mg/kg) and then injected with [3H]proline 2 h prior to sacrifice at 24, 48, or 72 h. The reduction in CDP labeling observed at 24 h was fully reversed by 48-72 h. Moreover, by 72 h, the-rate of weight gain by dexamethasone-treated mice was similar to vehicle-treated controls. These data show that administration of dexamethasone to neonatal mice leads to a selective decrease in bone collagen synthesis within 24 h that is accompanied by down-regulation of osteocalcin and COL1A1 mRNA levels. This model will be useful in determining mechanisms by which high dose glucocorticoids inhibit bone formation in vivo.
...
PMID:Dexamethasone suppresses in vivo levels of bone collagen synthesis in neonatal mice. 898 46

Our previous studies have demonstrated that lipocortin 1 (LC1, also called annexin 1) is an important mediator of glucocorticoid action in the neuroendocrine system, particularly with regard to the powerful inhibitory actions of the steroids on the secretion of ACTH and its hypothalamic releasing hormones. In the present study, we have used an antisense oligodeoxynucleotide (ODN) unique to LC1 to investigate further the role of this protein in the regulatory effects of dexamethasone on ACTH release in vitro from rat anterior pituitary cells. Pituitary cells dispersed with collagenase retained their functional and morphological integrity in vitro and sequestered ODNs in a time-dependent manner from the incubation medium. LC1 was readily detected in the cells by Western blot analysis or by immunoprecipitation/autoradiography after preloading with 35S-methionine/cysteine; the bulk of the protein was contained within an intracellular pool but a small amount was attached to the outer cell surface (pericellular). Dexamethasone (100 nm, 2.5 h) initiated de novo synthesis of LC1; it also increased the amount of LC1 in the pericellular pool detected by either method and caused a concomitant decrease in intracellular LC1. The responses to the steroid were prevented by the inclusion in the medium of an LC1 antisense ODN (50 nM, 3.5 h) but the corresponding sense and scrambled ODN sequences were inert. None of the ODN sequences tested influence the expression of annexin 5 in the pituitary tissue. CRH-41 (100 pM-1 mM), forskolin (1 nM-1 mM) and an L-Ca2+-channel opener BAY K8644 (100 pM-1 microM) initiated concentration dependent increases in immunoreactive- (ir-) ACTH release from the pituitary cells that were reduced (P < 0.01) by preincubation with dexamethasone (100 nM, 2.5 h). The inhibitory effects of the steroid were reversed by the LC1 antisense ODN (50 nM, P < 0.01), whereas the LC1 sense and scrambled control sequences (50 nM) were both ineffective in this respect (P > 0.05). The results add further support to the view that the acute inhibitory effects of glucocorticoids on the secretion of ACTH by the pituitary gland are dependent on the generation of lipocortin 1.
...
PMID:An antisense oligodeoxynucleotide to lipocortin 1 reverses the inhibitory actions of dexamethasone on the release of adrenocorticotropin from rat pituitary tissue in vitro. 920 35

Cholestatic liver injury induces an inflammatory response that follows the activation of hepatic macrophages. Constitutive activation of the transcription factor, NF-kappaB, was found in these macrophages over the course of hepatic injury. Since NF-kappaB activation has been shown to have a key role in the inflammatory process, the modulatory effects of the antioxidant, alpha-tocopherol succinate, and the glucocorticoid, dexamethasone, on NF-kappaB activation were examined in this study. Male Sprague Dawley rats underwent 2-7 days of common bile duct division and ligation (CBDL) or sham laparotomy. Hepatic macrophages were isolated by collagenase Pronase perfusion and purified by centrifugal elutriation. Activation was determined by electrophoretic mobility shift assay and ELISA. We determined that NF-kappaB activation in injured hepatic macrophages could only be inhibited by dexamethasone. Dexamethasone-mediated inhibition of NF-kappaB activation required the synthesis of a regulatory protein since cycloheximide-treated cells were resistant to its effects. Furthermore, dexamethasone-treated hepatic macrophages showed elevated steady-state levels of IkappaB-alpha mRNA, suggesting the role of IkappaB-alpha as a potential regulatory mediator. Consistent with constitutive transcriptional activation we showed constitutive secretion of TNF-alpha from injured hepatic macrophages which could be inhibited by dexamethasone. These data show for the first time, in a biologically significant model of hepatic injury, constitutive activation of the key inflammatory transcription factor NF-kappaB and cytokine TNF-alpha. These results support an approach focused on the NF-kappaB/IkappaB-alpha pathway as a critical target for therapeutic intervention during hepatic injury, and the consideration of possible steroid-based therapies.
...
PMID:NF-kappaB activation and modulation in hepatic macrophages during cholestatic injury. 935 33

We have previously reported that ursolic acid, a pentacyclic triterpene acid, inhibited the invasion of HT1080 human fibrosarcoma cells by reducing the expression of matrix metalloproteinase-9. Since the chemical structure of ursolic acid is very similar to that of dexamethasone, a synthetic glucocorticoid, we investigated whether ursolic acid acts through the glucocorticoid receptor. The expression of matrix metalloproteinase-9 is thought to be regulated similarly with matrix metalloproteinase-1 and matrix metalloproteinase-3 as containing common 2-O-tetradecanoylphorbol-acetate responsible region, where AP-1 proteins can bind. Dexamethasone has been studied to repress the 2-O-tetradecanoylphorbol-acetate-induced expression of matrix metalloproteinase-1 and matrix metalloproteinase-3 through a glucocorticoid receptor-mediated manner. In Northern blot analysis, we found that ursolic acid reduced the expression of matrix metalloproteinase-1 and matrix metalloproteinase-3 induced by 2-O-tetradecanoylphorbol-acetate. Similarly, ursolic acid down-regulated 2-O-tetradecanoylphorbol-acetate-induction of matrix metalloproteinase-9 gene in the same manner of dexamethasone. RU486, a potent glucocorticoid receptor antagonist, was used for identifying that ursolic acid-induced down-regulation of matrix metalloproteinase-9 expression is mediated by its binding to glucocorticoid receptor. The effect of ursolic acid on the matrix metalloproteinase-9 expression was blocked by RU486, suggesting that ursolic acid acts via a glucocorticoid receptor in the regulation of matrix metalloproteinase-9. Western blot analysis and immunocytochemistry showed that ursolic acid increased glucocorticoid receptor fraction in the nucleus, although it decreased the synthesis of glucocorticoid receptor mRNA. In addition, ursolic acid did not decrease the expression of c-jun and DNA-binding activity of AP-1 to its cognate sequences. Taken together, we suggest that ursolic acid may induce the repression of matrix metalloproteinase-9 by stimulating the nuclear translocation of glucocorticoid receptor, and the translocated glucocorticoid receptor probably down-modulating the trans-activating function of AP-1 to 2-O-tetradecanoylphorbol-acetate responsible element of matrix metalloproteinase-9 promoter region.
...
PMID:Ursolic acid-induced down-regulation of MMP-9 gene is mediated through the nuclear translocation of glucocorticoid receptor in HT1080 human fibrosarcoma cells. 948 41


<< Previous 1 2 3 4 5 Next >>

---