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)

In the immune system macrophages are the cells responsible for nitric oxide (NO) production. The synthesis of NO by activated macrophages correlates with their cytotoxic effect on neoplastic cells as well as killing of intracellular parasites. In the present paper we test several parameters that may influence (in vitro) NO production by murine peritoneal macrophages previously stimulated in vivo by intraperitoneal injection of thioglycollate. In our system the maximum NO/NO2- release was obtained in the culture containing 10(6) M phi/ml after 24 h incubation. For macrophage activation we used lipopolysaccharide (LPS) and several recombinant cytokines (IFN-gamma, TNF-alpha, IL-2, IL-3, IL-6). We also tested the influence of latex phagocytosis on NO production by simultaneously activated macrophages.
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PMID:An improved experimental model for the study of in vitro release of nitric oxide by murine peritoneal macrophages. 750 53

The immune cytokine interleukin-1 (IL-1) causes a pronounced elevation in substance P (SP) immunoreactivity and the mRNA coding for its preprotachykinin precursor in cultured superior cervical (sympathetic) ganglia (SCG; Jonakait and Schotland, 1990; Freidin and Kessler, 1991; Hart et al., 1991). In this study we have investigated the possibility that the SCG can respond to other immune stimulators, notably lipopolysaccharide (LPS), a product of bacterial cell walls. LPS treatment of cultured SCG resulted in a dose-dependent increase in SP. However, LPS did not induce SP in the absence of non-neuronal cells, suggesting the necessity of a non-neuronal cell-derived intermediate. Since the LPS induction of SP was partially blocked by a specific IL-1 receptor antagonist (IL-1ra) and since LPS induced approximately an 8-fold increase in mRNA coding for IL-1 itself, we concluded that IL-1 is at least one of these LPS-induced intermediates. TNF-alpha, which also raises SP levels, may be another. IL-6, which may also be increased by LPS, does not increase levels of SP. The synthetic glucocorticoid hormone dexamethasone (DEX) blocks the LPS induction of SP with a Ki approximating 8 x 10(-11) M. The inhibition is due in part to the blockade of the LPS induction of ganglionic IL-1 mRNA. Moreover, inhibition of the LPS induction of SP by indomethacin implies mediation of the effect through prostaglandins. The inhibition by indomethacin suggests a non-monocytic cell source since prostaglandins are thought to restrict the LPS induction of monocytic IL-1.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Lipopolysaccharide induces substance P in sympathetic ganglia via ganglionic interleukin-1 production. 750 97

Nitric oxide (NO) contributes to the antitumor, antimicrobial, and immunosuppressive activity of macrophages. An inducible form of NO synthase (iNOS) is responsible for high output generation of nitric oxide by macrophages after stimulation with cytokines and/or lipopolysaccharide (LPS). In the present study, we demonstrate that interleukin 4 (IL-4) suppressed production of NO by primary mouse peritoneal macrophages exposed to IFN-gamma with or without LPS, even while synergizing with IFN-gamma to increase the secretion of TNF-alpha. Suppression of NO production was paralleled by decreases in iNOS enzyme activity and iNOS antigen. IL-4 did not inhibit induction of iNOS mRNA 4-6 h after exposure to IFN-gamma, but strongly reduced iNOS mRNA at later times of stimulation (24-72 h), without increasing its turnover. The conditions for maximal suppression of iNOS expression by IL-4 and the mechanisms of suppression differed from those determined in parallel for transforming growth-factor-beta as described elsewhere. These results illustrate the diversity of phenotypes of macrophages deactivated by different cytokines, and demonstrate that IL-4 has the potential to reduce one component of the anti-tumor, antimicrobial, and immunosuppressive activities of macrophages.
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PMID:Mechanism of suppression of nitric oxide synthase expression by interleukin-4 in primary mouse macrophages. 750 68

Production of nitric oxide (NO) by macrophages is enhanced upon activation by bacterial endotoxins and cytokines mainly via an increase of the intracellular content of the inducible isoform of nitric oxide synthase (i-NOS). We have studied in detail the effect of several modulators of macrophage activity on steady state levels of i-NOS mRNA in the mouse macrophage-like cell line RAW 264.7. Bacterial lipopolysaccharide (LPS) and interferon-gamma (IFN-gamma) were found to be effective inducers of i-NOS mRNA, in accordance with their known ability to stimulate both i-NOS activity and NO production in macrophages from different sources, while TNF-alpha, IL-1, or IL-6 was ineffective in this regard. Accumulation of i-NOS mRNA in response to either LPS or IFN-gamma stimulation was accompanied by increased i-NOS gene transcription, as detected both by using a nuclear "run-on" transcription assay and by transient transfection of the cloned gene promoter in RAW 264.7 cells. Co-stimulation of the cells with both inducers resulted in higher steady state levels of i-NOS mRNA in the absence, however, of a corresponding potentiation of the rate of gene transcription. This was due primarily to a considerable effect of LPS on i-NOS mRNA stability, with prolongation of its half-life from 1-1.5 h, in the presence of IFN-gamma alone, to 4-6 h in the presence of both LPS and IFN-gamma.
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PMID:Dual mechanism for the control of inducible-type NO synthase gene expression in macrophages during activation by interferon-gamma and bacterial lipopolysaccharide. Transcriptional and post-transcriptional regulation. 751 Jun 85

Cytokine-inducible nitric oxide (NO) production has been implicated in the pathogenesis of septic shock. The present study was designed to determine which cytokines induce expression of the NO synthase gene in rat aortic vascular smooth muscle cells (VSMC) in vitro and whether NO synthase gene expression is inducible in vivo. NO synthase mRNA appeared after 4-h exposure to interleukin-1 beta (IL-1 beta), and levels continued to increase up to 24 h. Levels of NO synthase transcripts were greatest in VSMC treated with IL-1 beta (1 nM), lower in VSMC treated with Escherichia coli lipopolysaccharide (LPS; 100 micrograms/ml), and just detectable in VSMC treated with tumor necrosis factor-alpha (TNF-alpha; 1 nM). IL-1 beta, TNF-alpha, and LPS each induced NO synthase activity, assessed by release of nitrite, conversion of L-arginine to L-citrulline, and increased levels of guanosine 3',5'-cyclic monophosphate, whereas IL-2, IL-6, and interferon-gamma were ineffective. IL-1 beta was more potent and effective than TNF-alpha; however, submaximal concentrations of TNF-alpha acted synergistically with IL-1 beta to induce NO synthase gene expression and activity. Inducible NO synthase mRNA was present in aorta from rats 6 h after treatment with LPS (5 mg/kg), but not at 24 h. Synergistic activation of NO synthase gene expression in VSMC by IL-1 beta and TNF-alpha may contribute to hypotension in sepsis.
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PMID:Interleukin-1 beta and tumor necrosis factor-alpha synergistically induce NO synthase in rat vascular smooth muscle cells. 751 63

Glycosyl phosphatidylinositol (GPI)-anchored membrane proteins are deficient in the blood cells affected by paroxysmal nocturnal hemoglobinuria (PNH). The relation of the deficiencies of CD59 and CD14 with the clinical features of PNH are reported. CD59 binds to complement components C8 and C9 derived from human sera and inhibits the C5b-9-mediated hemolysis in a species-selective manner. The CD59-binding sites were revealed to be localized in the alpha subunit of C8 and in the "b" domain of C9 (thrombin fragment). The deficiency of CD59 in PNH is causatively related to the hemolytic features in PNH. A monocyte differentiation antigen, CD14, is deficient in the affected PNH monocytes. CD14 is reported to be one of the receptors to lipopolysaccharide (LPS). LPS-binding to the monocytes were revealed to be mediated through CD14 on monocytes. Enhancement of LPS-binding to monocytes by the presence of serum was not seen to PNH-affected monocytes. PNH-affected monocytes showed impaired TNF-alpha production in response to LPS. The deficiency of CD14 indicates the abnormality in PNH-affected monocytes, however, its significance in the clinical features of PNH is to be clarified.
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PMID:[Clinical features and diagnosis of paroxysmal nocturnal hemoglobinuria: correlates with the deficiency of GPI-anchored membrane proteins]. 751 13

This study describes the expression characteristics of E-selectin molecules using immunogold histochemical techniques on cultured human umbilical vein endothelial cells (HUVEC). The expression of E-selectin was induced by tumour necrosis factor-alpha (TNF-alpha, 300 U/ml), phorbol ester (PMA, 10 ng/ml) and bacterial lipopolysaccharide (LPS, 4 micrograms/ml). No expression was demonstrated on control cells. Using the silver-enhanced colloidal gold-labelling technique, at the light microscopical level, HUVEC could be distinctively subdivided into three staining types. The cell labelling index, expressed as the number of 'positively' stained cells as a proportion of all viewed cells was the highest in the LPS group. For transmission electron microscopy (TEM) the preembedding immunocytochemical staining method and embedding in epoxy resin (Agar 100) according to standard procedures was used. In TEM gold particles were localized in close association with the apical plasma membrane, as well as on the surface of microvillus-like projections (the latter by TNF-alpha group). For high resolution scanning electron microscopy (HR-SEM) the secondary (SEI) and the backscattered electron imaging (BEI) modes were used. Gold particles were randomly distributed over the whole cell surface, although they appeared to be denser in the perinuclear zone. The quantitative evaluation on SE and BE viewing (the number of gold particles per cell area in microns 2) demonstrated the highest density of labelling in the LPS-treated group, but there was only a significant difference between LPS and TNF-alpha groups (P < 0.01, t-test). Furthermore, the ultrastructural studies indicated that treatment with substances which up-regulate E-selectin expression was not related to toxic cell damage or significant alterations of cellular ultrastructure.
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PMID:Application of immunogold labelling for light and electron microscopic localization of endothelial leukocyte adhesion molecule 1 (ELAM-1) on cultured human endothelial cells. 752 Aug 16

This study examined effects of blood-contacting materials on the monocyte reaction following the first contact of human blood with hollow fibre dialyser membranes under pyrogen-free conditions. Membrane materials were the unchanged regenerated cellulose, the synthetic polysulphone (PS), a positively charged diethylaminoethyl cellulose (DEAE-C), the negatively charged carboxymethyl cellulose (CMC) and acrylonitrile copolymer (AN). The experimental system involved perfusion with human fresh venous blood through different modules containing the materials in the form of hollow fibre membranes. Extracellular and intracellular aspects of blood reactions after the first contact with the materials were investigated in Ficoll-separated granulocytes and peripheral blood mononuclear cells. Investigations were done by release reactions of platelet activating factor (PAF), oxygen radical (O2-), leukotriene B4, prostaglandin E2 (PGE2) and cytokines (IL-1 beta, TNF-alpha, IL-6). The intracellular activation of peripheral blood mononuclear cells was done by mRNA transcription of IL-1 beta, TNF-alpha, IL-6, IL-8 and beta 2-microglobulin (beta 2-MG). From the set of parameters, release reactions were only measurable for PAF, PGE2 and O2- if a second stimulus (phorbol myristate acetate, lipopolysaccharide, zymosan and calcium ionophore) was used after blood-membrane interaction. Although the extent of the release reaction was weak, negatively charged membranes were, in general, more active. All dialysers exhibited the same increase in beta 2-MG mRNA transcription, suggesting that all blood-contacting membranes initiate the gene expression of beta 2-MG at the same level. TNF-alpha, IL-6, IL-1 beta and IL-8 mRNAs were demonstrated in the AN and CMC membranes rather than the other materials, which exhibit a lower transcription than the tubing set. As has been found, an enhanced generation of PGE2 for both CMC and AN membranes supports, therefore, the concept of an effect of the negative charges of the materials in the gene expression of cytokines. However, this initiation does not lead to the generation of cytokines, even after stimulation with pyrogens.
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PMID:Effect of dialyser membranes on extracellular and intracellular granulocyte and monocyte activation in ex vivo pyrogen-free conditions. 753 Sep 99

Both fish oil-derived omega-3 polyunsaturated fatty acid (omega 3 PUFA) supplementation and essential fatty acid (EFA) deficiency have been shown to exert anti-inflammatory effects and, hence, to ameliorate immune-mediated glomerulonephritis. The mechanisms underlying these effects include alterations in the production of eicosanoids, cytokines (that is, tumor necrosis factor, TNF-alpha) and reactive oxygen species by blood borne cells. Because, in addition to these mediators nitric oxide (NO) is also implicated in glomerular injury, we have examined if both diets affected macrophage NO production as well. Rats were fed a standard chow, an omega 3 PUFA-supplemented diet, or an EFA-deficient diet for six weeks before resident peritoneal macrophages were isolated. These cells were exposed to lipopolysaccharide (LPS) and the NO metabolite, nitrite (NO2-), was measured in the medium using the Griess reagent. Release of NO2- was enhanced by LPS in a dose-dependent manner. With 10 ng/ml LPS challenge, NO2- release was reduced by 37% and 57% by omega 3 PUFA supplementation and EFA deficiency, respectively. NO2- returned to control levels two weeks after the end of diet. Macrophage production of TNF-alpha responded in a similar manner. Diet-induced reduction of NO2- release was neither attributable to a reduction of inducible NO synthase mRNA levels as shown by Northern blot analysis, nor to an increased competition of NO synthase and arginase for the substrate (L-arginine). Indeed, arginase activity of macrophages was even slightly reduced by both omega 3 PUFA-supplemented diet and EFA-deficient diet.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Fish oil supplementation and essential fatty acid deficiency reduce nitric oxide synthesis by rat macrophages. 753 89

Ovine tumour necrosis factor-alpha (OvTNF-alpha) was cloned by reverse transcription-polymerase reaction using RNA isolated from lipopolysaccharide (LPS)-stimulated alveolar macrophages and primers based on the human TNF-alpha cDNA sequence. An expression vector carrying the coding sequence of the mature form of ovine TNF was constructed. The recombinant Ov-TNF alpha (rOvTNF-alpha) was expressed as a glutathione-S-transferase (GST) fusion protein. It was cleaved with thrombin to yield rOvTNF free of the GST moiety. Growth at a lower temperature of 30 degrees C and use of Escherichia coli strains AM207, AM305, E392 and NM522 did not improve the recovery of rOvTNF-alpha from the soluble fraction to a significant extent. Purification of recombinant proteins was achieved rapidly and easily by affinity chromatography using glutathione-Sepharose. Yields of pure rOvTNF-alpha achieved in E. coli JM109 and AM207 were approximately 1 mg L-1. Both rOvTNF-alpha and recombinant human TNF-alpha (rhTNF-alpha) exerted cytotoxicity on L929 cells. However, rOvTNF-alpha but not rhTNF-alpha stimulated proliferation of ovine thymocytes. Maximum levels of TNF-alpha mRNA expression by LPS-stimulated ovine alveolar macrophages were detected at approximately 4 h post-stimulation.
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PMID:Expression, biological activity and kinetics of production of recombinant ovine TNF-alpha. 753 48


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