Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.1.27.4 (ribonuclease)
 6,621 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The peritoneum has been shown to possess fibrinolytic activity which is thought to play a role in the prevention of intra-abdominal adhesion formation. Recently inflamed peritoneal tissue has been shown to have reduced fibrinolytic activity secondary to increased levels of plasminogen activator inhibitor-1 (PAI-1). The aim of this study was to localize the production of PAI-1 in appendix tissue using in situ mRNA hybridization. Sections of normal and inflamed appendix were hybridized with a digoxigenin-labelled cDNA probe. PAI-1 production was localized to both mesothelium and serosal blood vessel endothelium in all inflamed appendix samples. Cell identities were confirmed using immunohistochemistry directed against mesothelial and endothelial cell markers. Staining was not seen on 1 probe following ribonuclease digestion). The identification of the cells expressing the PAI-1 gene in peritoneum increases our understanding of the pathophysiological changes in fibrinolytic activity which occur in inflammation and may lead to adhesion formation.
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PMID:Localization of plasminogen activator inhibitor-1 production in inflamed appendix by in situ mRNA hybridization. 843 16

The hypothesized relationships between plasminogen activator inhibitor (PAI-1) genotypes, PAI-1 levels, and their potential regulation by hypertriglyceridemic (HTG) very low density lipoprotein (VLDL) and lipoprotein(a) [Lp(a)] was examined in a PAI-1 genotyped human umbilical vein endothelial cell (HUVEC) culture model system. Individual human umbilical veins were used to obtain cultured ECs and were genotyped for PAI-1 by using the HindIII restriction fragment length polymorphism (RFLP) as a marker for genetic variation. Digested genomic DNA, examined by Southern blot analysis and probed with an [alpha-32P]dCTP-labeled 2.2-kb PAI-1 cDNA, yielded three RFLPs designated 1/1 (22-kb band only), 1/2 (22-plus 18-kb bands), and 2/2 (18-kb band only). Individual PAI-1 genotyped HUVEC cultures were incubated in the absence or presence of HTG-VLDL (0 to 50 micrograms/mL) or Lp(a) (0 to 50 micrograms/mL) at 37 degrees C for various times (4 to 24 hours), followed by analyses of PAI-1 antigen (by ELISA) and mRNA (by ribonuclease protection assay) levels, EC surface-localized plasmin generation assays, and nuclear run-on transcription assays. Secreted PAI-1 antigen levels were increased approximately 2- to 3-fold by HTG-VLDL and approximately 1.6 to 2-fold by Lp(a); mRNA levels were increased approximately 3- to 4.5-fold by HTG-VLDL and approximately 2.5- to 3.2-fold by Lp(a) compared with medium-incubated controls, primarily in the 2/2 PAI-1 genotype HUVEC cultures. Increases in PAI-1 mRNA induced by HTG-VLDL or Lp(a) could be abolished by coincubation with actinomycin D (2 x 10(-6) mol/mL) or puromycin (1 microgram/mL). In addition, nuclear transcription run-on assays typically demonstrated that HTG-VLDL increased PAI-1 gene transcription rates by approximately 5- to 6-fold and approximately 4- to 5-fold, respectively, primarily in the 2/2 PAI-1 genotype HUVEC cultures compared with 1/1 PAI-1 genotype HUVEC cultures or medium-incubated controls. The positive control interleukin-1 increased both 2/2 and 1/1 PAI-1 mRNA levels by approximately 5- to 6-fold. Increased PAI-1 antigen and mRNA expression were associated with a concomitant 50% to 60% decrease in plasmin generation. These combined results demonstrate the genotype-specific regulation of PAI-1 expression by HTG-VLDL and Lp(a) and further indicate that these risk factor-associated components regulate PAI-1 gene expression at the transcriptional level in cultured HUVECs. Results from these studies further suggest that individuals with this responsive 2/2 PAI-1 genotype may reflect the additional inherent potential for later HTG-VLDL- or Lp(a)-induced fibrinolytic dysfunction, resulting in the early initiation of thrombosis, atherogenesis, and coronary artery disease.
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PMID:Genotype-specific transcriptional regulation of PAI-1 expression by hypertriglyceridemic VLDL and Lp(a) in cultured human endothelial cells. 940 14

Transforming growth factor-beta1 (TGF-beta1) is a cytokine expressed by mammary cells. While TGF-beta1 can inhibit the proliferation of human breast cancer cells, many cell lines are unresponsive to it. To shed light on the mechanisms underlying resistance to TGF-beta1, we examined expression of the mediators of TGF-beta1 signaling in the mammary carcinoma cell lines MCF-7, T47D, ZR-75-1, BT-20, MDA-MB-231 and MDA-MB-468. The levels of mRNA encoding Smad2, 3 and 4 as well as the type II (TbetaRII) and type I (TbetaRI) membrane receptors were determined by Northern analysis and/or ribonuclease protection assays. Smad2 and Smad3 mRNAs were detected in all 6 cell lines examined, whereas Smad4 mRNA was not detected in MDA-MB-468 cells, which are known to harbor a homozygous deletion of the Smad4 gene. TbetaRI was expressed in all 6 cell lines, whereas TbetaRII was not detected in ZR-75-1 and T47D cells. Of the cell lines tested, only MCF-7 cells were growth-inhibited by TGF-beta1. In contrast, only MDA-MB-231 cells showed induction of the PAI-1 promotor in response to TGF-beta1. We also examined the regulation of Smad mRNA expression by estrogens and androgens in ZR-75-1 cells. Neither estradiol nor dihydrotestosterone affected Smad2, 3 or 4 mRNA levels in ZR-75-1 cells. These results indicate that the lack of response to TGF-beta1 in the breast cancer cell lines examined can be attributed to the absence of either TbetaRII or the Smad4 gene product. Moreover, we show that the proliferative and transcriptional responses to TGF-beta1 are dissociable and that Smad expression is not regulated by sex steroids in ZR-75-1 cells.
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PMID:Expression profile of agonistic Smads in human breast cancer cells: absence of regulation by estrogens. 1007 59

Classically, activated protein C (APC) of the protein C/protein S anticoagulant pathway has functioned not only to inactivate the procoagulant factors Va and VIIIa but also to inhibit the activity of plasminogen activator inhibitor-1 (PAI-1). More recent data have suggested that the protein C/protein S pathway may serve as a physiological link between coagulation and inflammation. This APC pathway link was proposed because of observations showing that APC could both modulate the effects of cytokines and block neutrophil activation. As a further extension of the effect(s) of APC on cytokines, we found that APC, at the equivalent physiological protein C concentration of 4 microg/ml, significantly upregulated monocyte chemotactic protein-1 (MCP-1) RNA in human umbilical vein endothelial cells (HUVECs), as indicated by a ribonuclease protection assay (RPA) at 3 and 6 h with a return to near basal levels by 24 h. ELISA determinations demonstrated that 4 microg/ml of APC induced a significant (P=.0001) increase in MCP-1 protein production over basal levels within a 24-h period. At the same concentration, APC downregulated endothelial cell nitric oxide synthase (eNOS) RNA. Downregulation first became apparent at 6 h and continued through 48 h of culture. This downregulation was concentration dependent over a range of 1.3-12 microg/ml, and there was no effect on cell viability within this range. In support of other studies, we also found that exogenously added nitric oxide (NO) inhibited MCP-1 production. These data suggest that APC may induce MCP-1 through the inhibition of eNOS.
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PMID:Activated protein C induction of MCP-1 in human endothelial cells: a possible role for endothelial cell nitric oxide synthase. 1167 83