Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P43026 (lipopolysaccharide)
 62,215 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The fibrinolytic potential of the endothelial cells gives important antithrombotic properties to the vascular wall. Thrombosis is a frequent complication to atherosclerosis and other conditions where inflammatory mediators are present in the vascular wall. Inflammatory agents like lipopolysaccharide (LPS) and tumor necrosis factor-alpha (TNF alpha) have been demonstrated to modulate the expression of fibrinolytic factors in cultured endothelial cells. In the present study the expression of tissue-type plasminogen activator (t-PA), urokinase plasminogen activator (u-PA) and plasminogen activator inhibitors-1 and -2 (PAI-1 and PAI-2) antigen in conditioned medium from cultured human umbilical vein (HUVEC) and human saphenous vein (HSVEC) endothelial cells was investigated under basal conditions and after stimulation with LPS, TNF alpha, interferon-gamma (IFN-gamma) or interleukin-6 (IL-6) alone or in combinations. Stimulation with LPS or TNF alpha increased the expression of PAI-1, u-PA and PAI-2 in HUVEC and HSVEC, while the t-PA response differed between the two cell types. The effects of TNF alpha were modulated by IFN-gamma but not by IL-6. The increased expression of u-PA after stimulation with TNF alpha was reduced by IFN-gamma. In contrast, TNF alpha-induced expression of PAI-2 was synergistically increased by addition of IFN-gamma. These effects of IFN-gamma represent additional mechanisms by which inflammatory mediators may turn the fibrinolytic potential of the endothelium in a prothrombotic direction.
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PMID:Interferon-gamma modulates the fibrinolytic response in cultured human endothelial cells. 777 58

The plasminogen activator inhibitor PAI-1 is markedly elevated in vivo and in vitro upon exposure to the inflammatory mediators tumor necrosis factor alpha (TNF alpha), interleukin-1 (IL-1), and bacterial lipopolysaccharide. Here we report that the isoflavone compound genistein prevents the increase in synthesis of PAI-1 induced by these inflammatory mediators in human endothelial cells in vitro, and partially reduces the basal PAI-1 production by these cells. These effects of genistein were accompanied by a decrease in PAI-1 mRNA and in a suppression of the PAI-1 transcription rate as shown by run-on assay. A specific action of genistein, probably by inhibiting a tyrosine protein kinase, is likely, because the structural genistein analogue daidzein, which has a low tyrosine protein kinase inhibitor activity, did not inhibit PAI-1 synthesis. Vanadate, a tyrosine protein phosphatase inhibitor, increased PAI-1 production. The effect of genistein on PAI-1 synthesis was rather selective. Herbimycin A also reduced PAI-1 synthesis, but several other tyrosine protein kinase inhibitors, namely tyrphostin A47, methyl-2,5-dihydroxy-cinnamate, and compound 5, were unable to do so. All these tyrosine protein kinase inhibitors reduced basic fibroblast growth factor (b-FGF)-induced [3H]thymidine incorporation in endothelial cells. This indicates that the effect of genistein on PAI-1 transcription proceeds independently of its effect on mitogenesis. In contrast to TNF-alpha-induced PAI-1 production, the transcription and synthesis of urokinase-type plasminogen activator (u-PA) was not inhibited by genistein. A TNF-alpha-mutant (Trp32Thr86TNF alpha) that specifically recognizes the 55-kD TNF-receptor, mimicked the effects of TNF alpha on both PAI-1 and u-PA. Because genistein affected PAI-1, but not u-PA induced by this mutant, involvement of different TNF-receptors cannot underlie the difference in the effects of genistein on PAI-1 and u-PA synthesis. Because genistein also inhibited PAI-1 induction by thrombin and IL-4, it is likely that genistein does not act on a TNF alpha-receptor-coupled protein kinase but on the signal transduction pathway enhancing PAI-1 transcription. Our results suggest that the TNF alpha-induced signal transduction pathway of PAI-1 transcription involves a genistein-sensitive step that is not involved in the induction of u-PA by TNF alpha. Given the limited sensitivity to several other tyrosine protein kinase inhibitors, this genistein-sensitive step may be a potential target for pharmacologic intervention to reduce elevated plasma PAI-1 levels.
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PMID:Genistein reduces tumor necrosis factor alpha-induced plasminogen activator inhibitor-1 transcription but not urokinase expression in human endothelial cells. 794 70

Macrophage colony-stimulating factor (M-CSF or CSF-1) and granulocyte-macrophage CSF (GM-CSF) have been shown to increase human monocyte urokinase-type plasminogen-activator (u-PA) activity with possible consequences for cell migration and tissue remodeling; because monocyte u-PA activity is likely to be controlled in part also by the PA inhibitors (PAIs) made by the cell, the effect of M-CSF and GM-CSF on human monocyte PAI-2 and PAI-1 synthesis was investigated. To this end, elutriation-purified human monocytes were treated in vitro with purified recombinant human M-CSF and GM-CSF, and PAI-2 and PAI-1 antigen and mRNA levels measured by specific enzyme-linked immunosorbent assays and Northern blot, respectively. Each CSF could enhance the protein and mRNA levels of PAI-2 and PAI-1 at similar concentrations for each product. This similar regulation of monocyte PAI expression in response to the CSFs contrasted with that found for the effects of lipopolysaccharide, transforming growth factor-beta and a glucocorticoid. Therefore, PAIs may be modulating the effects of the CSFs on monocyte u-PA activity at sites of inflammation and tissue remodeling.
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PMID:Macrophage colony-stimulating factor and granulocyte-macrophage colony-stimulating factor stimulate the synthesis of plasminogen-activator inhibitors by human monocytes. 826 Jul

This study examined the effects of endogenous urokinase (uPA) on lipopolysaccharide (LPS)-stimulated tumor necrosis factor alpha (TNF-alpha) secretion in THP-1 mononuclear phagocytes. Anti-uPA monoclonal antibody (mAb) suppressed LPS-driven TNF-alpha secretion by 61.6 +/- 5.9% (P<.001), and PAI-1, a uPA inhibitor, suppressed it to 53.1 +/- 8.2% of the control value (P<.001). Up-regulation of TNF-alpha mRNA was suppressed in parallel with secreted TNF-alpha protein. TNF-alpha secretion was unaffected by depleting plasminogen or by aprotinin, a plasmin inhibitor. When endogenous uPA was displaced from the cell, exogenous high-molecular-weight (intact) uPA augmented LPS-driven TNF-alpha secretion. By contrast, a uPA fragment containing the catalytic domain was inhibitory, and the uPA receptor-binding domain had no effect. We conclude that endogenous uPA amplifies TNF-alpha neosynthesis of LPS-stimulated THP-1 mononuclear phagocytes. The effect requires intact uPA and is independent of plasmin activity. This represents a novel mechanism by which a mononuclear phagocyte-derived protease contributes to generating proinflammatory signals.
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PMID:Endogenously produced urokinase amplifies tumor necrosis factor-alpha secretion by THP-1 mononuclear phagocytes. 860 4

The direct effects of recombinant human erythropoietin(rHuEPO) on coagulation and fibrinolysis factors were evaluated in a cultured endothelial cell (EC) system. Confluent quiescent ECs were incubated with or without 5.0 U/ml rHuEPO for 1, 6, and 18 hours, and supernatant concentrations of plasminogen activator inhibitor-1 (PAI-1): antigen (Ag), tissue plasminogen activator and thrombomodulin, and supernatant activities of tissue factor pathway inhibitor and von Willebrand factor were measured. The results showed that only PAI-1 levels were increased by the presence of rHuEPO. In order to assess the effect of rHuEPO on PAI-1 production by EC more precisely, confluent ECs were incubated with various doses of rHuEPO (0, 1.0, 2.5, 5.0, 10.0 U/ml) for 1, 6, 12, and 18 hours, and PAI-1:Ag concentrations in the supernatants of media were measured. PAI-1:Ag in the supernatants were increased by the presence of rHuEPO at all incubation times (P < 0.01) and the increase in PAI-1:Ag was dependent on rHuEPO concentration. The increases in PAI-1:Ag by 5.0 U/ml rHuEPO were comparable to those by 0.1 U/ml tumor necrosis factor-alpha, 1.0 microgram/ml lipopolysaccharide, and 0.5 U/ml thrombin. The increase in PAI-1:Ag by rHuEPO was suppressed by pre-incubation with 10 micrograms/ml cycloheximide (P < 0.01) or 0.2 microgram/ml actinomycin D (P < 0.01). These results indicate that rHuEPO directly stimulates PAI-1 production in cultured EC via de novo protein and RNA syntheses.
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PMID:rHuEPO enhances the production of plasminogen activator inhibitor-1 in cultured endothelial cells. 880 78

Human peritoneal mesothelial cells (HMC) play a critical role in maintaining the intraperitoneal balance between fibrinolysis and coagulation by expressing the fibrinolytic enzyme tissue-type plasminogen activator (t-PA) as well as a specific plasminogen activator inhibitor, PAI-1, and the procoagulant protein tissue factor (TF). Of three compounds known to stimulate t-PA synthesis in cultured human endothelial cells, i.e., retinoic acid, the protein kinase C activator 4 beta-phorbol 12-myristate 13-acetate (PMA), and sodium butyrate, only butyrate (1 mM) caused about a threefold increase in t-PA synthesis and mRNA expression in HMC after 24 h of incubation, without markedly affecting PAI-1 synthesis. PMA (10 nM) induced a threefold increase in urokinase-type plasminogen activator (u-PA) mRNA, but u-PA antigen levels in the HMC conditioned media remained below the detection level (0.5 ng/ml), possibly as a result of rapid uptake and degradation by the u-PA receptor. The u-PA receptor mRNA levels were about fivefold enhanced above control levels after PMA treatment of the cells. An increase in intracellular adenosine 3',5'-cyclic monophosphate levels by forskolin (10 microM) diminished t-PA and PAI-1 levels 43 and 17%, respectively. Among the inflammatory mediators tested [tumor necrosis factor-alpha (TNF-alpha), interleukin-1 alpha, and bacterial lipopolysaccharide], TNF-alpha (10-1,000 U/ml) showed the strongest procoagulant effects. We found that the isoflavone compound genistein (25 micrograms/ml) prevented the TNF-alpha-induced expression of PAI-1 and TF while also slightly counteracting the decrease in t-PA synthesis. The protein kinase C inhibitor R0-318220 (3 microM) only moderately opposed the TNF-alpha-induced changes in t-PA and PAI-1 synthesis but completely prevented the induction of TF mRNA. In summary, our results demonstrate that t-PA synthesis in HMC is relatively insensitive to pharmacological stimulation. To restore the balance between fibrinolysis and coagulation under inflammatory conditions, attempts to interfere with the TNF-alpha-signaling pathway were more successful.
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PMID:Modulation of procoagulant and fibrinolytic system components of mesothelial cells by inflammatory mediators. 894 61

Tissue-type plasminogen activator (t-PA) and its physiological inhibitor, plasminogen activator inhibitor-1 (PAI-1), are known to be synthesized by vascular endothelial cells and to play important roles in regulating the fibrinolytic activity of plasma. We found that a new butadiene derivative, (3E, 4E)-3-benzylidene-4-(3,4,5-trimethoxybenzylidene)pyrrolidine -2,5-dione (T-686), inhibits PAI-1 production without affecting plasminogen activator (PA) synthesis in cultured bovine endothelial cells. T-686 (1-10 microM) dose-dependently decreased the accumulation of PAI-1 in conditioned medium from the treated cells and elevated PA activity in the conditioned medium. Analysis of the conditioned medium by the zymography technique indicated that T-686 decreased the activities of PAI-1 with an M(r) of 55,000 and t-PA/PAI-1 complex with an M(r) of 99,000. Furthermore, T-686 attenuated the augmentation of PAI-1 antigen induced by lipopolysaccharide in the conditioned medium. The decrease of PAI-1 antigen was in parallel with the reduction of the PAI-1 mRNA level (Northern blots). These results suggest that T-686 can promote net fibrinolytic activity through suppression of PAI-1 production without affecting PA elaboration in endothelial cells.
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PMID:Inhibitory effect of a new butadiene derivative on the production of plasminogen activator inhibitor-1 in cultured bovine endothelial cells. 901 Jul 71

In this study we investigated a possible counteracting activity notoginsenoside R1 (NG-R1) on lipopolysaccharide (LPS)-induced effects in vitro and in vivo. The upregulation of plasminogen activator inhibitor-1 (PAI-1) antigen due to LPS (1 microgram/mL for 12 hours) in human umbilical vein endothelial cells (HUVECs) was prevented when the cells were incubated simultaneously with 100 micrograms/mL NG-R1 (PAI-1 antigen: LPS-treated cells, 969 +/- 54 ng/10(5) cells; control cells, 370 +/- 15 ng/10(5) cells; LPS + NG-R1-treated cells, 469 +/- 29 ng/10(5) cells; n = 6). The 2.5- and 3.4-fold (2.2- and 3.2-kb) increases in PAI-1 mRNA levels induced by LPS (1 microgram/mL for 6 hours) were reduced to 1.4- and 2.6-fold increases in the presence of both LPS and 100 micrograms/mL NG-R1. LPS-induced tissue factor (TF) activity in HUVECs was also counteracted when the cells were coincubated with both LPS and 100 micrograms/mL NG-R1 for 6 hours (TF activity: LPS-treated cells, 88.6 +/- 6.5 mU/10(6) cells; control cells, 0.7 +/- 0.01 mU/10(6) cells; LPS + NG-R1-treated cells, 56.0 +/- 1.9 mU/10(6) cells). The 26-fold increase in TF mRNA levels induced by LPS (1 microgram/mL for 2 hours) was reduced to a 13-fold increase in the presence of both LPS and 100 micrograms/mL NG-R1. PAI activity levels in the plasma of mice 4 hours after injection of LPS (10 ng/g body wt) increased 2.3-fold compared with a control group. In contrast, PAI activity from LPS + NG-R1 (1 microgram/g body wt NG-R1)-treated animals was at control level (PAI-1 activity: LPS-treated group, 11.3 +/- 3.1 U/mL; control group, 4.9 +/- 0.3 U/mL; LPS + NG-R1-treated group, 4.3 +/- 1.0 U/mL; n = 5 to 8). The production of TNF-alpha induced by 1 microgram/mL LPS by cultured human whole-blood cells was inhibited by 46% when the cells were incubated together with 100 micrograms/mL NG-R1. NG-R1 protected mice from the lethal effects of LPS. The 78% lethality induced by LPS/galactosamine was reduced to 23% when NG-R1 was administered simultaneously (P < .01 by chi 2 test). To extend this study to inflammatory cells, the effect of NG-R1 on LPS stimulation of the monocytic cell line THP-1 was investigated. NG-R1 inhibited the LPS-induced degradation of I kappa B-alpha and superinduced LPS-induced I kappa B-alpha mRNA, indicating that the effect of NG-R1 is not restricted to endothelial cells and is at least in part mediated by interference with the NF-kappa B/I kappa B-alpha pathway.
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PMID:Notoginsenoside R1 counteracts endotoxin-induced activation of endothelial cells in vitro and endotoxin-induced lethality in mice in vivo. 910 64

We have examined the effects of an inhibitor of plasminogen activator inhibitor-1 (PAI-1) production, (3E,4E)-3-benzylidene-4-(3,4,5-trimethoxy-benzylidene)pyrrol idine-2,5-dione (T-686), on lipopolysaccharide (LPS)-induced death in mice. Oral administration of T-686 (10 and 100 mg/kg/day) for 8 days prior to the LPS injection (35 mg/kg, i.v.) protected mice from the lethal effect of LPS in a dose-dependent fashion. Moreover, treatment with 100 mg/kg T-686 attenuated the increase in plasma PAI-1 activity and the decrease in AT-III activity induced by LPS. We conclude that T-686 can reduce the mortality of mice induced by LPS, which seems to be partially correlated with both hypercoagulation and hypofibrinolysis.
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PMID:Protective effect of T-686, an inhibitor of plasminogen activator inhibitor-1 production, against the lethal effect of lipopolysaccharide in mice. 943 61

A stable immortalized venous endothelial cell (IVEC) line, obtained by transfection of human umbilical vein endothelial cells (HUVEC), retains many normal differentiated endothelial characteristics. We compared the fibrinolytic activities of IVEC and HUVEC, and observed that IVEC express a more profibrinolytic phenotype than HUVEC, since they bind and activate plasminogen more efficiently, produce more tissue plasminogen activator and urokinase-type plasminogen activator antigens, and secrete less plasminogen activator inhibitor-1 antigen both under basal conditions and after stimulation with lipopolysaccharide, phorbol ester and tumor necrosis factor. Moreover, immunostaining and Western blotting of IVEC for the plasminogen/tissue plasminogen activator receptor annexin II, as well as Northern blotting of annexin II mRNA, revealed similar patterns of surface expression in IVEC and HUVEC. Plasminogen activator inhibitor-2 is expressed similarly in both cell types. IVEC may be a useful human model for functional and pharmacological explorations and modulations of fibrinolytic system components.
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PMID:Profibrinolytic properties characterize a stably transformed human endothelial cell line. 962 13


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