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)

It is well established that cultured endothelial cells are induced to generate tissue factor activity when incubated with either endotoxin or thrombin. In this study a perfusion system was used on 3-4 cm long human saphenous veins. The veins were perfused with thrombin (2.5 U/ml), endotoxin (30 ng/ml) or just medium for 3 h at 37 degrees C. After the perfusion, the veins were treated with collagenase, and EC were collected and subjected to tissue factor activity measurements. Some perfused veins were examined for tissue factor activity on the vessel wall by allowing factor VII and factor X to interact with the lumen of the intact vessels, followed by quantitation of generated factor Xa in a chromogenic assay. No formation of tissue factor activity could be found after perfusion in either collagenase-dissolved endothelial cells or in the coupled chromogenic assay for tissue factor activity performed in the lumen of the vessel. Our data strongly suggest that endothelial cells in intact endothelium may behave quite differently from isolated endothelial cells stimulated in cell cultures.
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PMID:Lack of ability to synthesize tissue factor by endothelial cells in intact human saphenous veins. 213 38

Synthesis and secretion of blood coagulation factor X was studied during incubations of hepatocytes prepared by perfusion of rat livers with collagenase. The apparent molecular weight of factor X isolated from the incubation medium was about 14,000 less than factor X isolated from rat plasma. The extracellular form of factor X was a two-chain polypeptide and the observed difference in molecular weight was reflected in the heavy chain. Since these properties were more characteristic of factor Xa than factor X, experiments were designed to determine if factor X activation occurred during the incubations. Clotting factor assays indicated that factor X secreted by hepatocytes was present as factor Xa. Also, when purified plasma factor X was added to incubations of hepatocytes the added factor X was converted to factor Xa. Plasma membranes prepared from isolated hepatocytes or from liver homogenates contained an enzyme that converted factor X to factor Xa in a calcium-dependent reaction. The results suggest that the activity is due to the presence of thromboplastin (tissue factor) and factor VII in the membrane preparations.
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PMID:The activation of factor X by hepatocyte plasma membranes. 261 30

Metabolic heterogeneity has previously been demonstrated for cloned fibroblast populations. It is unclear whether a "high producer" or "activated" phenotype for one cell product reflects general metabolic activation or whether activated phenotypes for different metabolic markers segregate independently among cloned populations. We examined human foreskin fibroblast substrains, isolated by limiting dilution cloning, for heterogeneity in biosynthesis of PGE2 and collagenase (stimulated by Interleukin 1-containing mononclear cell supernates), and tissue factor. Synthesis of these products varied 5- to 10-fold among 16 substrains isolated from two parent lines (AT and WB). Metabolic phenotypes (high versus low levels of synthesis) were stable for the substrains over multiple weeks of culture. In neither group of substrains was there a correlation between levels of stimulated PGE synthesis and stimulated collagenase synthesis (r = -0.24 and 0.29 for AT and WB substrains, respectively). Similarly, tissue factor generation did not correlate with either PGE production (r = 0.12 and -0.38 for AT and WB substrains, respectively) or collagenase synthesis (r = 0.17 and 0.21 for AT and WB substrains, respectively). The discordance between high producer phenotypes for the different products was observed even when all three products were measured in the same culture. Activated phenotypes for different metabolic markers thus appear to segregate among cells independently. The process of connective tissue activation by immune cell-derived mediators may depend on the constituent makeup of the responding connective tissue cell population.
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PMID:Synthesis of PGE2, collagenase and tissue factor by fibroblast substrains: substrains are differentially activated for different metabolic products. 300 12

Tissue factor (TF) is a major activator of the coagulation cascade and may play a role in initiating thrombosis after intravascular injury. To investigate whether medial vascular smooth muscle provides a source of TF following arterial injury, the induction of TF mRNA and protein was studied in balloon-injured rat aorta. After full length aortic injury, aortas were harvested at various times and the media and adventitia separated using collagenase digestion and microscopic dissection. In uninjured aortic media, TF mRNA was undetectable by RNA blot hybridization. 2 h after balloon injury TF mRNA levels increased markedly. Return to near baseline levels occurred at 24 h. In situ hybridization with a 35S-labeled antisense rat TF cRNA probe detected TF mRNA in the adventitia but not in the media or endothelium of uninjured aorta. 2 h after balloon dilatation, a marked induction of TF mRNA was observed in the adventitia and media. Using a functional clotting assay, TF procoagulant activity was detected at low levels in uninjured rat aortic media and rose by approximately 10-fold 2 h after balloon dilatation. Return to baseline occurred within 4 d. These data demonstrate that vascular injury rapidly induces active TF in arterial smooth muscle, providing a procoagulant that may result in thrombus initiation or propagation.
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PMID:Tissue factor is rapidly induced in arterial smooth muscle after balloon injury. 768 1

Endothelial cells grown on filters developed junctional complexes that reduced diffusional transport and increased electrical resistance over the cell layer. Induction of tissue factor by recombinant interleukin-1 beta led to a highly polarized tissue factor expression on the apical cell surface only. After prolonged growth to allow deposition of matrix, removal of the endothelial cells by collagenase or by 0.1 mol/L NH4OH left behind some cellular material as well as tissue factor, which was only detectable in the upper compartment. A human bladder carcinoma cell line, which does not form tight junctions and expresses tissue factor constitutively, showed essentially no polarity. Endothelial cell secretory compounds like von Willebrand factor, tissue plasminogen activator, and plasminogen activator inhibitor-1 were constitutively released to both sides. The added secretion due to recombinant interleukin-1 beta stimulation of the endothelial cells observed for von Willebrand factor and tissue plasminogen activator was, however, localized to the apical surface. The availability of tissue factor on the luminal surface of endothelial cells, ie, allowing contact with factor VII in the flowing blood, has potentially very significant pathophysiological consequences.
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PMID:Polar expression of tissue factor in human umbilical vein endothelial cells. 794 8

A discrepancy exists between basal tissue factor (TF) expression found in endothelial cell cultures and the failure to detect TF in unpertubated endothelial cells in vivo. We demonstrated that basal TF expression in endothelial cell cultures originated from contaminating cells. These cells were ultrastructurally and flowcytometrically identified as smooth muscle cells. The cell cultures had been obtained from collagenase-treated human umbilical cord vessels. Histologic studies revealed that after collagenase treatment the basement membrane was digested and underlying structures were disrupted at some areas of the vein. We selected chymotrypsin as an alternative for the isolation of endothelial cells. Using chymotrypsin, the endothelial lining was selectively lost leaving the basement membrane undisturbed. Furthermore, use of chymotrypsin instead of collagenase minimized the level of basal TF activity. Taken together, we demonstrated that basal TF expression in endothelial cell cultures is caused by contaminating smooth muscle cells. This contamination can strongly be reduced using chymotrypsin instead of collagenase for isolation of endothelial cells.
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PMID:Basal tissue factor expression in endothelial cell cultures is caused by contaminating smooth muscle cells. Reduction by using chymotrypsin instead of collagenase. 858 1

The pathogenesis of venous leg ulcers is based on the leakage of fibrinogen leading to a pericapillary fibrin cuff and plugging of capillaries by white blood cells. On the basis of a previous work, we had assumed that the key event in the pathogenesis of venous leg ulcers is related to inflammation generated by activated white blood cells that accumulate under unrelieved blood pressure, because in ulcer biopsies we had detected the presence of tumor necrosis factor-alpha (TNF-alpha) in intracapillary monocytes, elastase in the polymorphonuclear leukocytes near the vessels, and a pericapillary undegraded fibrin cuff causing a diffusion barrier to oxygen. This concept was developed because TNF-alpha synthesized by activated monocytes is responsible for many deleterious effects. It has a potent mitogenic effect on fibroblasts, leading to new collagen deposition and angiogenesis, it induces an increase in collagenase production, it acts through upregulation of an intracellular adhesion molecule (ICAM-1), leading to leukocyte sequestration and consequently a release of toxic metabolites by the polymorphonuclear cells, an early step in chronic inflammation, it activates the coagulation pathway via a marked increase in monocyte-associated tissue factor (TF) procoagulant activity, and it inhibits fibrinolysis by promoting the release of PAI-1, contributing to undegraded fibrin deposition. Therefore, we were interested in evaluating, in patients with venous leg ulcers, the effect of pentoxifylline administered at 1,200 mg daily (versus placebo) for 2-months, as this drug induces a decrease in TNF-alpha synthesis and also blocks its activity. This pilot assay was performed in blind. Evolution of several parameters in ulcer biopsies are analyzed: TNF-alpha, intact fibrin, fibrin degradation products, ICAM-1, TF, and elastase. Pentoxifylline administration induced a decrease of local elastase and of fibrin deposit. These results support the hypothesis that accumulation of activated leukocytes is the key event in venous leg ulcers.
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PMID:Expression of elastase and fibrin in venous leg ulcer biopsies: a pilot study of pentoxifylline versus placebo. 869 46

Stimulated monocytes are involved in blood clotting and fibrin dissolution by synthesizing tissue factor (TF) and fibrinolytic components such as plasminogen activator inhibitor type 2 (PAI-2). Heparin interacts with smooth muscle cells, platelets, and endothelial cells and specifically binds to human monocytes. In endothelial and smooth muscle cells, heparin selectively inhibits collagenase and tissue plasminogen activator gene expression. To investigate (1) heparin's influence on the hemostatic system by its interactions with plasma factors and cellular elements and (2) to determine its effects on gene expression in blood circulating cells, we studied the effect of heparin on TF and PAI-2 protein and mRNA in human lipopolysaccharide (LPS)- or interferon-gamma (IFN-gamma)-stimulated monocytes. TF and PAI-2 proteins were investigated by ELISA and by assaying procoagulant activity. The mRNA study was carried out by an initial PCR screening followed by a Northern blot semiquantitative analysis. Heparin (0.5 U/mL) inhibited both TF and PAI-2 production and gene expression. The contemporaneous protein and mRNA decrease (TF and PAI-2 protein 22 and 42%, respectively; suggests that this action is, at least partially, at the transcriptional level. The effect is not specific for heparin and is not demonstrated by other glycosaminoglycans (chondroitin-4-sulfate or dermatan sulfate). This action may be relevant for the antithrombotic activity of heparin in cell-mediated blood clotting activation.
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PMID:Tissue factor and plasminogen activator inhibitor type 2 expression in human stimulated monocytes is inhibited by heparin. 920 Mar 37

Sodding of vascular grafts involves coating the biomaterial with cells prepared from collagenase-digested fat tissue after removal of the adipocytes by centrifugation. The goal of this study was to investigate the staining characteristics of the sodding cells as well as their ability to express the procoagulant protein tissue factor, and to compare these findings to those found with extensively purified microvascular endothelial cells (MEC) prepared from similar tissue. Sodding cells and MEC, isolated using immunomagnetic separation with anti-PECAM antibodies, were prepared from liposuction material and endothelial-specific staining was compared. The expression of tissue factor on these cells was examined using both an ELISA and a chromogenic assay to assess the rate of generation of factor Xa. Sodding cells expressed significantly more tissue factor than the unstimulated MEC in which the expression was undetectable (sodding cells 2466 +/- 830 pg/mL, P < 0.05). There was no further increase in tissue factor expression in the sodding cells with stimulation with lipopolysaccharide (LPS); however, purified MEC expressed significantly more tissue factor after exposure to LPS (1247 +/- 356 pg/mL, P < 0.05). These results were confirmed by the determination of procoagulant activity of the cells whereby the procoagulant activity on unstimulated MEC was significantly less than that found after stimulation of these cells, and it was also less than stimulated and unstimulated sodding cells (absorbance at 405 nm: 0.423 +/- 0.125, unstimulated MEC; 1.000 +/- 0.438, stimulated MEC; 1.129 +/- 0.396, unstimulated sodding cells; 1.171 +/- 0.254, stimulated sodding cells, P < 0.05). Staining of these two cells types also demonstrated significant uptake of acetylated LDL (Ac-LDL) in the purified MEC which was essentially absent in the sodding cells. Further, vWf staining was found to a greater degree in the purified MEC than in the sodding cells. These experiments demonstrated that the cells prepared for cell sodding express large amounts of tissue factor. The sodding cells do not stain for antigens known to be specific for endothelial cells, whereas MEC do and therefore the concentration of endothelial cells in the sodding cells is small. The significance of the tissue factor expression on the surface of sodded grafts is not yet known.
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PMID:Tissue factor expression by cells used for sodding of prosthetic vascular grafts. 934 10

As a model system for the identification of genes involved in the progression of human breast cancer, differential gene expression in cell lines MCF-7 and MCF-7ADR was investigated. The latter cell line is derived from the former. Cell line MCF-7 is estrogen receptor-positive, vimentin-negative and uninvasive in the Matrigel outgrowth assay and in the nude mouse, while MCF-7ADR is estrogen receptor-negative, hormone-resistant, vimentin-positive, invasive in the Matrigel outgrowth assay and in the nude mouse and resistant to adriamycin due to overexpression of glycoprotein gp170. We have shown that tumor progression in this model system is mediated by transcriptional regulation of mitochondria-related genes, proteases, transmembrane receptors and cell cycle-related gene proteins. Among the genes differentially regulated at the transcriptional level in the cell lines MCF-7 and MCF-7ADR are a new mitochondrial transcript, mitochondrial creatine kinase, matrix metalloproteinase-1, stromelysin-3, urokinase and its receptor, tissue factor, E-cadherin, epidermal growth factor receptor, transmembrane proteins Mat-8 and progression associated protein (PAP), cyclin E, cyclin-dependent kinase-2 and cell cycle inhibitory proteins p16, p21 and p27.
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PMID:Molecular analysis of two mammary carcinoma cell lines at the transcriptional level as a model system for progression of breast cancer. 951 94


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