Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:2.7.7.49 (reverse transcriptase)
 31,746 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The effects of cyclic strain on the production of tissue plasminogen activator (tPA) and type 1 plasminogen activator inhibitor (PAI-1) by cultured endothelial cells (EC) were examined. Human saphenous vein EC were seeded in selective areas of culture plates with flexible membrane bottoms (corresponding to specific strain regions) and grown to confluence. Membranes were deformed by vacuum (-20 kPa) at 60 cycles/min (0.5 s strain alternating with 0.5 s relaxation in the neutral position) for 5 days. EC grown in the periphery were subjected to 7-24% strain, while cells grown in the center experienced less than 7% strain. The results show a significant increase in immunoreactive tPA production on days 1, 3 and 5 compared to day 0 in EC subjected to more than 7% cyclic strain. There was no significant elevation of tPA in the medium of EC subjected to less than 7% strain. tPA activity could only be detected in the medium of EC subjected to more than 7% cyclic strain. PAI-1 levels in the medium were not significantly different in either group. In addition, immunocytochemical detection of intracellular tPA and messenger ribonucleic acid (mRNA) expression of tPA (assessed by the reverse transcriptase polymerase chain reaction utilizing tPA specific sense and antisense primers) was significantly increased in EC subjected to more than 7% cyclic strain. We conclude that a 60 cycles/min regimen of strain that is greater than 7% can selectively stimulate tPA production by EC in vitro and may contribute to the relative nonthrombogenicity of the endothelium in vivo.
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PMID:Tissue plasminogen activator expression in endothelial cells exposed to cyclic strain in vitro. 128 45

Fluid shear stress can stimulate secretion of tissue plasminogen activator (tPA) by cultured human endothelial cells, while plasminogen activator inhibitor type-1 secretion remains unstimulated. To determine whether hemodynamically induced changes in tPA messenger RNA (mRNA) levels also occur, primary cultures from the same harvest of primary human umbilical vein endothelial cells were either maintained in stationary culture or exposed to arterial levels of shear stress (25 dynes/cm2) for 24 hours. Total cellular RNA was isolated from the shear stressed and stationary cultures and the relative levels of tPA mRNA and glyceraldehyde 3-phosphate dehydrogenase (GAPDH) mRNA were determined using a coupled reverse transcriptase/polymerase chain reaction method. As indicated by the amount of amplification product, tPA mRNA levels were many fold higher (greater than 10) in endothelial cells subjected to shear stress for 24 hours than in stationary controls. In contrast, mRNA levels for GAPDH were similar in control and shear stressed cells. The constancy of the measured GAPDH signal indicated that the tPA response was a selective effect of fluid shear stress. When a similar polymerase chain reaction method was used, the mRNA levels of basic fibroblast growth factor (bFGF) were found not to vary in comparison to GAPDH mRNA after 24 hours of shear stress. These results indicate that enhancement of the fibrinolytic potential of endothelial cells in response to hemodynamic forces could involve transcriptional events.
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PMID:Tissue plasminogen activator messenger RNA levels increase in cultured human endothelial cells exposed to laminar shear stress. 211 Jan 69

Human proteinase inhibitor 6 (PI-6) is a recently described protein belonging to the serine proteinase inhibitor (serpin) superfamily. Sequence similarity suggests that PI-6 most resembles the ovalbumin (ov) serpins which include plasminogen activator inhibitor-2, the squamous cell carcinoma antigen, monocyte/neutrophil elastase inhibitor, and maspin. Although these proteins are associated with carcinomas and inflammation, they appear to have diverse functions and little is known of their physiological roles. In this study we have characterized cDNA and genomic clones encoding mouse PI-6 in order to analyze the localization, structure, and expression of the gene. The reactive center residues (Arg-Cys) are conserved in the mouse molecule, and recombinant mouse PI-6 was shown to bind thrombin, indicating that it has similar inhibitory properties to its human counterpart. Using reverse transcriptase-polymerase chain reaction assays on RNA isolated from 15-day-old embryos and adult mice, we have shown that mouse PI-6 expression is developmentally regulated, and that, unlike human PI-6, it is absent from the placenta. The mouse homologue of the human PI-6 gene has been designated Spi3 and was mapped to chromosome 13 between the Pl1 and ctla2 alpha genes. It spans 20 kilobases, consists of 7 exons and 6 introns, and contains a TATA motif 24 nucleotides upstream of the transcriptional start site. A 680-base pair DNA fragment containing this motif and 31 nucleotides of the 5'-untranslated region of the structural gene directed transcription of a bacterial cat gene, demonstrating the presence of a functional promoter. The PI-6 gene lacks an intron present in the ovalbumin and PAI-2 genes; otherwise it is identical in terms of the numbers, position, and phasing of the intron/exon boundaries. These results suggest that PI-6 and the ov-serpin genes have diverged and do not belong to the same subgroup.
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PMID:Gene structure, chromosomal localization, and expression of the murine homologue of human proteinase inhibitor 6 (PI-6) suggests divergence of PI-6 from the ovalbumin serpins. 760 71

Altered expression of plasminogen activator inhibitors (PAIs) is of potential relevance to the process of lung fibrosis. To clarify the involvement of PAIs in interstitial lung diseases, we examined whether alterations in PAI-1 and PAI-2 were induced in response to a single intratracheal administration of a fibrosing dose of crystalline silica in mice (5 mg x animal(-1)). The time course of changes in PAI activity and PAI-1 protein were characterized in bronchoalveolar lavage fluid (BALF) and changes in PAI-1 and PAI-2 messenger ribonucleic acid (mRNAs) were monitored by reverse transcriptase polymerase chain reaction (RT-PCR) in BALF cells and lung tissue up to the fibrotic stage of the disease. Substantial levels of PAI activity were found in BALF of control animals, whereas no PAI-1 protein was detected. In response to silica treatment, we observed an acute increase of PAI activity and PAI-1 protein levels in BALF (day 1), associated with an induction of PAI-1 and PAI-2 mRNA levels in lung tissue. In alveolar macrophages, silica treatment induced a persistent upregulation of PAI-2 mRNA only. One month after silica treatment, PAI activity was undetectable in BALF while substantial PAI activity was still present in controls. At the same time point, sustained upregulation of PAI-1 and PAI- 2 mRNAs was, however, noted in lung tissue of animals treated with silica. These findings support the possible implication of PAIs in the remodelling process induced by silica in the lung.
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PMID:Expression of plasminogen activator inhibitors type-1 and type-2 in the mouse lung after administration of crystalline silica. 962 97

The expression of urokinase-type plasminogen activator (u-PA), u-PA receptor (u-PAR) and plasminogen activator inhibitor (PAI) 1 and 2 was examined in 105 cases of primary lung cancer tissue using immunohistochemical staining and reverse transcriptase polymerase chain reaction (RT-PCR) techniques. The expression of u-PA, u-PAR and PAI-1 was detected in approximately 80% of primary lung cancers, whereas detectable PAI-2 expression was observed only in half of the overall cases. We assessed the relationships between the expression pattern and clinicopathological findings and found that a diminished expression level of PAI-2 was significantly correlated with lymph node metastasis and a poor prognosis. These results indicate that PAI-2 may play a critical role in the regulation of extracellular matrix degradation during tumour cell invasion and metastasis, and the expression of PAI-2 may be useful as a marker for evaluating the prognosis of lung cancer.
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PMID:Significance of plasminogen activator inhibitor 2 as a prognostic marker in primary lung cancer: association of decreased plasminogen activator inhibitor 2 with lymph node metastasis. 974 10

The plasmin activation system plays a key role in extracellular matrix degradation in many malignant tumors. Because no data are available on the involvement of the plasmin activation system in matrix degradation by thyroid carcinoma, the present study was performed using follicular thyroid carcinoma cell lines obtained from a primary tumor (FTC-133) and metastases (FTC-236 and FTC-238) of one patient. Matrix degradation by these cell lines was studied assessing the release of radioactivity from S35-methionine labeled extracellular matrix coated onto plastic. The involvement of constituents of the plasmin activation system as well as matrix metalloproteinases (MMPs), another class of proteolytic enzymes, which can be activated by plasmin, were assessed by semiquantitative reverse transcriptase-polymerase chain reaction (RT-PCR) and zymography. In the matrix degradation experiment, S35 release by FTC-133 was significantly higher than FTC-236 and FTC-238. S35 degradation could be inhibited by the plasmin inhibitor aprotinin and by anti-human urokinase-type plasminogen activator (uPA) antibody, indicating the involvement of the plasmin activation system. Matrix degradation could also be inhibited by the MMP inhibitor marimastat, thus demonstrating the involvement of MMPs in matrix degradation by these cell lines. Zymographic assays revealed activity of uPA in all cell lines. However, in contrast with FTC-236 and FTC-238, no plasminogen activator inhibitor (PAI) or PAI1 mRNA were found in FTC-133. Therefore, the differences in PAI activity as observed between the cell lines may originate from differences in PAI1 gene transcription. Differences in PAI1 expression did not affect the attachment of these cell lines to vitronectin. We conclude that the plasmin activation system is involved in extracellular matrix degradation by these metastatic follicular thyroid carcinoma cell lines. Differences in extracellular matrix degradation between the cell lines correspond with differences in PAI1 gene expression, indicating the significance of PAI1 in extracellular matrix degradation by metastatic follicular thyroid carcinoma.
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PMID:Degradation of extracellular matrix by metastatic follicular thyroid carcinoma cell lines: role of the plasmin activation system. 1052 70

In this report we compared the mechanism by which nitric oxide (NO), generated exogenously and endogenously, affects the plasminogen activator inhibitor type 1 (PAI-1) expression in endothelial cells. For this purpose, we stimulated the endothelial cell line EA.hy 926 with tumour necrosis factor alpha (TNFalpha) in the presence of the exogenously NO-releasing donors, sodium nitroprusside (SNP) and S-nitroso-N-acetylpenicillamine, or regulators of nitric oxide synthase (NOS) inhibitor N-nitro-L-arginine-methyl ester hydrochloride and substrate L-Arg. Expression of PAI-1 in EA.hy 926 cells was determined by measuring the level of mRNA, using relative quantitative reverse transcriptase PCR, and protein, using ELISA. In addition, we estimated the level of activation of two mitogen-activated protein kinases (MAPKs), extracellular signal-regulated kinase (ERK1/2) and c-Jun N-terminal kinase (JNK1/2), in the cells before and after treatment with TNFalpha, in the presence or absence of NO donors and inhibitors. In contrast to exogenously released NO that significantly reduced mostly basal PAI-1 expression, endogenously generated NO by NOS potentiated TNFalpha-induced upregulation of PAI-1 expression. Exogenously and endogenously generated NO causes different effects on activation of the MAPKs ERK1/2 and JNK1/2. Specifically, the SNP-released NO activates only ERK1/2, while endogenously generated NO in a pathway induced by TNFalpha activates both MAPKs. Thus our data indicate that due to different cellular locations and mechanisms of generation, NO may participate in various signalling pathways leading to opposite effects on PAI-1 expression in endothelial cells.
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PMID:Dual regulatory effects of nitric oxide on plasminogen activator inhibitor type 1 expression in endothelial cells. 1067 8

Inflammation and tissue trauma during the surgical procedure reduce the peritoneal fibrinolytic capacity. These conditions promote adhesion formation, and are associated with increased expression of transforming growth factor beta 1 (TGF-beta1). The objective of the present study was to investigate whether TGF-beta1 regulates the expression of fibrinolytic components in peritoneal mesothelial cells. Human peritoneal mesothelial cells (HPMC) were cultured and treated with various concentrations of human recombinant TGF-beta1 (0.1, 1.0 and 10 ng/mL) for 24 h. Levels of tissue- and urokinase plasminogen activator (t-PA and uPA), plasminogen activator inhibitor type-1 (PAI-1) and type-2 (PAI-2) mRNA and protein were assessed by quantitative reverse transcriptase polymerase chain reaction (Q-RT-PCR) and ELISA, respectively. HPMC expressed these components at the gene and protein level. TGF-beta1 downregulated, dose-dependently t-PA mRNA and protein to about 50% of control values (p = 0.0010), and doubled PAI-1 protein production (p = 0.0008) compared to untreated controls. Although uPA gene expression increased in cells exposed to TGF-beta1, the corresponding protein concentration in conditioned media did not. PAI-2 was not affected, either at the gene or protein level. In conclusion, the results indicate that fibrinolytic capacity of mesothelial cells is reduced by TGF-beta1, suggesting that peritoneal adhesion formation induced by TGF-beta1 may be mediated, in part, through reduction in fibrin degradation capacity at an early stage of peritoneal tissue repair.
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PMID:Differential regulation of mesothelial cell fibrinolysis by transforming growth factor beta 1. 1112 59

We evaluated the hypothesis of sterol-regulatory element-binding protein (SREBP)-1c being a general mediator of the transcriptional effects of insulin, with a focus on adipocytes, in which insulin profoundly influences specific gene expression. Using real time quantitative reverse transcriptase-PCR to monitor changes in the expression of about 50 genes that cover a wide range of adipocyte functions, we have compared the impact of insulin treatment with that of adenoviral overexpression of either dominant positive or dominant negative SREBP-1c mutants in 3T3-L1 adipocytes. As expected, insulin up-regulated, dominant positive stimulated, and dominant negative decreased previously characterized direct SREBP targets (FAS, SCD-1, and low density lipoprotein receptor). We also identified three novel SREBP-1c transcriptional targets in adipocytes, which were confirmed by run-on assays: plasminogen activator inhibitor 1, CCAAT/enhancer-binding protein delta (C/EBPdelta), and C/EBPbeta. Because most insulin-regulated genes were also modulated by SREBP-1c mutants, our data establish that 1) SREBP-1c is an important mediator of insulin transcriptional effects in adipocytes, and 2) C/EBPbeta is under the direct control of SREBP-1c, as demonstrated by the ability of SREBP-1c to activate the transcription from C/EBPbeta promoter through canonical SREBP binding sites. Thus, some of the effects of insulin and/or SREBP-1c in mature fat cells might require C/EBPbeta or C/EBPdelta as transcriptional relays.
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PMID:Insulin and sterol-regulatory element-binding protein-1c (SREBP-1C) regulation of gene expression in 3T3-L1 adipocytes. Identification of CCAAT/enhancer-binding protein beta as an SREBP-1C target. 1204 7

Angiogenesis takes place during embryogenesis, characterized by the formation of new blood vessels from pre-existing ones. This biological process is also found in the female reproductive system, wound healing, and cancer development. Apoptosis, programmed cell death, is a physiological process in development, tissue homeostasis, and disease. Apoptosis is a normal event in several reproductive tissues including human placenta. In these studies, we investigated whether aberrant angiogenesis and apoptosis are associated with recurrent pregnancy loss (RPL). We compared the gene expression level for angiogenesis- and apoptosis-related genes in chorionic villi from RPL patients and those from normal controls. Semi-quantitative reverse transcriptase-polymerase chain reaction (RT-PCR) analysis revealed that 7 angiogenesis- and 12 apoptosis-related genes were abnormally expressed in chorionic villi from RPL patients. Angiogenesis-related genes that showed aberrant expression level are matrix metalloproteinase-2 (MMP-2), plasminogen activator inhibitor (PAI), integrin, transforming growth factor-beta (TGF-beta), vascular endothelial growth factor (VEGF), basic fibroblast growth factor (bFGF), and leptin receptor. Expression levels for these genes, except for leptin receptor, showed less in chorionic villi from RPL patients than those from normal controls. In contrast, higher expression levels of 12 apoptosis-related genes (caspase 3, 6, 7, 8, 9, 10, 12, BAD, BAX, BID, Fas, and FasL) were shown in chorionic villi from RPL patients than those from normal controls. Taken all together, it is likely that the lower expression of angiogenesis-related genes and the excessive expression of apoptosis-related genes are associated with RPL.
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PMID:Expression of angiogenesis- and apoptosis-related genes in chorionic villi derived from recurrent pregnancy loss patients. 1287 95


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