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)

CGP 47969A is a novel inhibitor of the biosynthesis of interleukin-1 and other cytokines, being developed as an anti-arthritic. The effect of the compound on lipopolysaccharide (LPS; 1 microgram/ml) stimulated nitric oxide (NO) production by the mouse macrophage cell line, J774A.1, was examined in the present study. CGP 47969A inhibited NO production in a concentration-dependent fashion (0.1-10 microM; IC50 = 2 microM) in a 24 h assay. Dexamethasone (Dex), which inhibits cytokine and inducible nitric oxide synthase (iNOS) gene transcription, and N-methyl arginine (NMA), a substrate analogue inhibitor of NOS activity, also inhibited NO production in this assay system with IC50 values of approximately 5 nM and 100 microM, respectively. When iNOS expression was induced by LPS for 24 h, CGP 47969A and Dex did not inhibit NO production, whereas NMA retained activity (IC50 = 40 microM). In time course experiments, CGP 47969A (10 microM) or Dex (1 microM) were added to J774A.1 cultures at t = 0, 1, 3 or 6 h after LPS. Dex inhibited NO production by 86%, 57%, 35% and 15% at these time points, while CGP 47969A inhibited by 90%, 91%, 89% and 76%. Taken together, the results indicate that CGP 47969A inhibits NO production by an effect similar to the inhibitory effect on cytokine production rather than by inhibition of iNOS enzyme activity per se or iNOS gene expression. The ability of CGP 47969A to inhibit cytokine and NO production may explain its efficacy in animal models of arthritis.
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PMID:Effects of the cytokine synthesis inhibitor CGP 47969A on nitric oxide production by lipopolysaccharide-stimulated J774A.1 macrophages. 774 Oct 43

Interleukin-2 (15 micrograms/mouse, i.p. twice daily for 4 days and once on the 5th day) significantly lowered cytochrome P-450 and heme content and increased heme oxygenase mRNA accumulation; the activities of 7-ethoxycoumarin O-deethylase, ethoxy- and pentoxyphenoxazone O-dealkylases were decreased. The activity of the type O form of hepatic xanthine oxidase increased, but there was no increase in lipid peroxide, expressed in terms of microsomal malondialdehyde. In vivo inactivation of xanthine oxidase activity by feeding mice with tungstate did not substantially change the degree of interleukin-2-induced cytochrome P-450 depression, suggesting that the two processes are not causally linked. Induction of tolerance to endotoxin by a 4-day pretreatment with lipopolysaccharide resulted in 50% protection against this depression despite inhibition of the interleukin-2 induced formation of tumor necrosis factor. This suggests that the release of tumor necrosis factor per se does not fully account for the depression of cytochrome P-450. Dexamethasone, already used in patients to reduce the toxicity of interleukin-2 therapy, provided full protection against the cytochrome P-450 depression.
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PMID:Mechanisms of interleukin-2-induced depression of hepatic cytochrome P-450 in mice. 779 64

Kupffer cells are known to produce tumor necrosis factor-alpha upon stimulation with endotoxin or viruses. This tumor necrosis factor-alpha synthesis is suppressed by prostaglandin E2 or dexamethasone. Using Northern blotting and reverse transcriptase-polymerase chain reaction, it is demonstrated that endotoxin-induced tumor necrosis factor-alpha synthesis is blocked by prostaglandin E2 or dibutyryl 3':5'-cyclic adenosine monophosphate on the transcriptional level. Tumor necrosis factor-alpha itself suppressed endotoxin-evoked tumor necrosis factor-alpha mRNA expression when given in a narrow time interval with lipopolysaccharide. Interleukin-10 of human or mouse origin also inhibited the synthesis of tumor necrosis factor-alpha mRNA and protein when given more than 2 h prior to the endotoxin challenge. The suppressive effect of prostaglandin E2 lasted for more than 36 h while IL-10 blocked tumor necrosis factor-alpha production for barely 24 h. Dexamethasone reduced the endotoxin-induced tumor necrosis factor-alpha mRNA formation by approximately 50% only, although it led to nearly complete inhibition of the synthesis of the mature protein. Taken together with reverse transcriptase-polymerase chain reaction data revealing significant amounts of tumor necrosis factor-alpha mRNA in resting Kupffer cells, an additional posttranscriptional regulation of tumor necrosis factor-alpha synthesis has to be assumed. Tumor necrosis factor-alpha mRNA was not induced by interferon-gamma, interleukin-1 beta or interleukin-6 (the latter two cytokines are also synthesized by Kupffer cells), but a 24-h prestimulation of liver macrophages with interferon-gamma or phorbol ester had a modest priming effect.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Regulation of the mRNA expression for tumor necrosis factor-alpha in rat liver macrophages. 793 Apr 83

The aim of our study was to characterize a model of human prostaglandin endoperoxide synthase-2 (PGHS-2) expression allowing the assessment of pharmacological inhibition in vitro and ex vivo. Heparinized human whole blood samples were incubated with lipopolysaccharide (LPS, 0.1-50 micrograms/ml) for 0 to 24 hr at 37 degrees C. The contribution of platelet PGHS-1 was suppressed by either pretreating the subjects with aspirin (300 mg 48 hr before sampling) or adding aspirin (10 micrograms/ml) in vitro at time 0. PGE2 was measured by radioimmunoassay. LPS induced expression of cyclooxygenase activity in a time- and concentration-dependent fashion. After 24 hr at 10 micrograms/ml LPS, PGE2 production averaged 12.1 +/- 6.2 ng/ml (mean +/- S.D., n = 7). Cyclooxygenase activity increased in parallel with the mass of a monocyte protein doublet analyzed by Western blot using antibodies directed against the carboxyl-terminal portion of human PGHS-2. Dexamethasone (2 microM) inhibited LPS-induced PGE2 production by 96 +/- 4% (mean +/- S.D., n = 3). Four different inhibitors were tested in vitro on the cyclooxygenase activity of LPS-induced monocyte PGH-2 and thrombin-stimulated platelet PGHS-1. IC50 values (microM) for inhibition of PGHS-1 and PGHS-2 were: indomethacin, 0.70 +/- 0.20 vs 0.36 +/- 0.10 (P < .05); S-indobufen, 0.64 +/- 0.22 vs. 14.9 +/- 8 (P < .05), R-indobufen, 38 +/- 18 vs. 230 +/- 68 (P < .01), 6-methoxy-2-naphthyl acetic acid (the active metabolite of nabumetone), 278 +/- 96 vs. 187 +/- 96.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Biochemical and pharmacological characterization of the cyclooxygenase activity of human blood prostaglandin endoperoxide synthases. 799 88

The role of mucosal fibroblasts in intestinal inflammatory reactions is not known. In this study, we demonstrate that fibroblasts grown from histologically normal human duodenal biopsy tissues expressed mRNA genes for granulocyte-macrophage colony-stimulating factor (GM-CSF), IL-1 alpha, IL-1 beta, IL-6, IL-8, IL-10, intercellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1) when stimulated with lipopolysaccharide (LPS) or IL-1 alpha. The increased mRNA expression of GM-CSF, IL-1 alpha, IL-1 beta, IL-6 and IL-8 in response to IL-1 alpha and LPS stimulation was time- and dose-dependent. In contrast, IL-10 was weakly expressed when fibroblasts were stimulated with LPS, IL-1 alpha or tumour necrosis factor-alpha (TNF-alpha), but the expression was enhanced in the presence of cycloheximide combined with optimal concentrations of LPS, IL-1 alpha or TNF-alpha, IL-1 alpha was a more potent stimulator than LPS for GM-CSF, IL-6, IL-8 and IL-10 expression, but not for IL-1 alpha and IL-1 beta. Increased GM-CSF, IL-6 and IL-8 gene expression was associated with the production of cytokine proteins in culture supernatant, but IL-1 alpha and IL-1 beta remained undetectable. Dexamethasone suppressed both gene expression and protein production of GM-CSF, IL-6 and IL-8 when fibroblasts were exposed to IL-1 alpha. TNF-alpha stimulated the release of GM-CSF, IL-6 and IL-8 and, combined with IL-1 alpha, cytokine production was enhanced synergistically. Finally, both LPS and IL-1 alpha up-regulated ICAM-1 and VCAM-1 gene expression. These findings implicate duodenal fibroblasts in the initiation and/or regulation of intestinal inflammation.
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PMID:GM-CSF, IL-1 alpha, IL-1 beta, IL-6, IL-8, IL-10, ICAM-1 and VCAM-1 gene expression and cytokine production in human duodenal fibroblasts stimulated with lipopolysaccharide, IL-1 alpha and TNF-alpha. 800 13

1. In guinea-pigs previously sensitized with ovalbumin, the intra-plantar administration of the antigen induced dose-dependent and sustained oedema. An intense infiltrate of neutrophils and eosinophils was observed at the peak of the oedema (4 h). 2. Oedema induced by ovalbumin at the doses of 50 or 200 micrograms/paw was not inhibited by antihistamines (meclizine and cetirizine), a PAF antagonist (BN 50730), a cyclo-oxygenase inhibitor (indomethacin), a lipoxygenase inhibitor (MK-886), a dual type lipo- and cyclo-oxygenase inhibitor (NDGA), a bradykinin antagonist (Hoe 140) or the combination of cetirizine, MK-886, indomethacin and BN 50730. These drugs did inhibit paw oedema induced by their specific agonists or by carrageenin. These results suggest that histamine, PAF, prostaglandins, leukotrienes or bradykinin are not important in the development of immune paw oedema in guinea-pigs. 3. Dexamethasone (10 mg kg-1) inhibited oedema induced by ovalbumin (50 or 200 micrograms/paw, P < 0.05). This effect apparently does not result from inhibition of arachidonate metabolism, since indomethacin, MK-886 and NDGA were without effect. 4. Oedema induced by ovalbumin (50 or 200 micrograms/paw) was also inhibited by azelastine. This effect was not due to the anti-histaminic property of azelastine since two other potent-antihistamines, meclizine and cetirizine, were ineffective. 5. Intravenous injection of lipopolysaccharide (LPS) dose-dependently inhibited the oedema induced by ovalbumin (200 micrograms/paw). This effect could not be attributed to hypotension or leucopenia since the maximal dose applied (81 micrograms kg-1) did not induce significant changes in the blood pressure or in the white blood cell levels of the animals. It is suggested that the effect of LPS is mediated by the endogenous release of cytokines, including tumour necrosis factor (TNF alpha). Murine TNF alpha dose dependently(9-81 microg kg-1) inhibited the paw oedema induced by ovalbumin.7. The anti-oedematogenic effects of LPS and/or TNF alpha are possibly associated with their capacity to inhibit leucocyte emigration. Accordingly, guinea-pigs rendered leucopenic with vinblastine exhibited less intense oedema after ovalbumin. Vinblastine did not affect oedema induced by PAF or bradykinin,indicating that vascular responsiveness was not involved.
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PMID:Drug modulation of antigen-induced paw oedema in guinea-pigs: effects of lipopolysaccharide, tumour necrosis factor and leucocyte depletion. 803 30

The effect of anti-inflammatory drugs on cytokine production at local inflammatory sites was investigated in a carrageenin-induced rat pleurisy model. Exudate volume and leukocyte number in the pleural cavity at 3 h after the carrageenin injection were significantly reduced by the pretreatment with indomethacin or dexamethasone. Both drugs also reduced the prostaglandin E2 level in the exudate. However, production of tumor necrosis factor (TNF) and interleukin-1 in the pleural exudate was significantly enhanced by the pretreatment with indomethacin, whereas the interleukin-6 level was reduced. Pretreatment with dexamethasone markedly suppressed all these cytokine levels. When resident pleural cells were stimulated with lipopolysaccharide in vitro, the presence of exogenous prostaglandin E2 reduced the production of TNF and interleukin-1, while it increased that of interleukin-6 in a dose-dependent manner. These results suggest that prostaglandin E2 could be a regulating factor involved in cytokine production at the inflammatory site. Dexamethasone may express a direct suppressive action on cytokine production rather than an indirect regulatory action through prostaglandin E2 level.
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PMID:Differential effects of indomethacin and dexamethasone on cytokine production in carrageenin-induced rat pleurisy. 815 61

To better understand the extrarenal production of active vitamin D metabolites by cells of the monocyte/macrophage lineage, we investigated the 25-hydroxyvitamin D (25OHD)-1-hydroxylation reaction in the v-myc-transformed chick myelomonocytic cell line HD-11; the 1-hydroxylation reaction in this cell line has a high affinity for 25-hydroxylated vitamin D substrates, is localized to mitochondria, and is associated with cytochrome P450 activity. In this study we demonstrated that the HD-11 cell 1-hydroxylation reaction in vitro is not affected by the majority of extracellular regulatory factors that modulate expression of the renal 25OHD-1-hydroxylase in vivo. A 50% increase in extracellular calcium and phosphate concentrations, physiological inhibitory events for renal 1,25-dihydroxyvitamin D [1,25-(OH)2D] synthesis, did not decrease basal expression of the HD-11 cell 1-hydroxylation reaction, nor did a 50% decrease in extracellular calcium and phosphate concentrations, stimulatory signals for the 1-hydroxylase in vivo, increase 1,25-(OH)2D3 synthesis in vitro. Receptor-saturating concentrations of PTH and PTH-related peptide were similarly without effect. In contrast, the HD-11 1-hydroxylation reaction was significantly stimulated in a dose-dependent fashion by the macrophage stimulatory agents lipopolysaccharide [P < 0.001 at a maximum effective concentration (EC100) of 25 micrograms/ml] and interferon-gamma (P < 0.001 at EC100 of 1000 IU/ml) and by insulin-like growth factor-I (P < 0.01 at EC100 of 15 nM) with the rank order of stimulation being interferon-gamma > lipopolysaccharide > insulin-like growth factor-I. Dexamethasone (> or = 10 nM) and the cytochrome P450 inhibitors (EC100, 20 microM), ketoconazole, clotrimazole, and menadione, all significantly inhibited the HD-11 cell 1-hydroxylation reaction. The naphthoquinone menadione, which blocks electron transfer to the P450-associated enzyme, was the most effective inhibitor of the reaction in both intact cells (3 +/- 1% of basal expression; P < or = 0.002) and after reconstitution of HD-11 cell mitochondrial extracts with a ferredoxin, reductase, O2, and NADPH (5 +/- 1% of basal; P < or = 0.02). We have also shown that 1,25-(OH)2D3 produced from substrate 25OHD3 appears to exert an endogenous (intracrine) inhibitory effect on HD-11 cell growth; incubation of HD-11 cells with a concentration of ketoconazole (10 microM) known to reduce 1,25-(OH)2D3 production by roughly 50% restored 50% of the growth deficit induced by 1,25-(OH)2D3 (EC100, 100 nM).(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Regulated production and intracrine action of 1,25-dihydroxyvitamin D3 in the chick myelomonocytic cell line HD-11. 819 84

Interleukin-8 (IL-8) is a neutrophil chemotactic factor expressed in many cell types, including human airway epithelial cells (HAEC). Inhaled corticosteroids are now used increasingly early in the treatment of airway inflammation such as in asthma, and directly interact with HAEC at relatively high concentrations. We have investigated the effect of dexamethasone on IL-8 expression in primary cultured HAEC obtained from transplantation donors. Northern blot analysis was used to measure IL-8 mRNA levels in HAEC, and radioimmunoassay was used to measure IL-8 protein in culture supernatant fluids. We demonstrated that IL-8 was expressed by primary cultured HAEC and that this was enhanced by IL-1 beta and tumour necrosis factor-alpha stimulation, but not by IL-6 or lipopolysaccharide. Dexamethasone suppressed IL-8 mRNA expression and protein synthesis dose-dependently in both resting and stimulated HAEC. The half-life of IL-8 mRNA determined in the presence of actinomycin D was less than 1 hr, and dexamethasone preincubation had no effect on mRNA stability. These results support the view that HAEC may play an important role in the pathogenesis of airway inflammatory diseases, and that glucocorticosteroids may exert their anti-inflammatory effects by blocking IL-8 gene expression and generation in these cells.
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PMID:Inhibition of interleukin-8 expression by dexamethasone in human cultured airway epithelial cells. 820 12

Tumour necrosis factor alpha (TNF alpha) has been reported to play a key role in the pathogenesis of sepsis and chronic inflammatory diseases, including rheumatoid arthritis and atherosclerosis, suggesting that agents which inhibit TNF alpha production may have therapeutic utility for the treatment of such conditions. Production of TNF alpha by LPS (lipopolysaccharide)-stimulated murine, rat and human heparinized blood was investigated. LPS (1-100 micrograms/ml) caused a similar concentration- and time-dependent stimulation of TNF alpha production by rat and human blood, achieving levels of 750-5000 U/ml (L929 bioassay) at 6 h. In contrast, TNF alpha production by LPS-stimulated murine blood was poor and variable (0-150 U/ml). Dexamethasone and pentoxifylline caused a concentration-dependent inhibition of TNF alpha production by LPS-stimulated human and rat blood with IC50s of 0.26 +/- 0.05 and 73.0 +/- 26.4 microM for human and 5.7 +/- 1.8 nM and 20.6 +/- 8.0 microM for rat blood, respectively. Therefore, LPS-stimulated rat and human, but not murine, blood are suitable systems for the detection and evaluation of inhibitors of TNF alpha production.
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PMID:Production of TNF alpha by LPS-stimulated murine, rat and human blood and its pharmacological modulation. 831 28


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