Indomethacin prevents the induction of inducible nitric oxide synthase in murine peritoneal macrophages and decreases their nitric oxide production

Indomethacin (0.1-0.5 mM concentration) inhibits nitric oxide production in murine peritoneal macrophages. This was evidenced by measuring both nitrite production or 14C-L-citrulline formation. The inhibition was caused by the diminution of de novo inducible nitric oxide synthase production as demonstrated by Western blotting experiment. The effect of indomethacin after 4 h treatment was irreversible. NO synthase and arginase activities and the uptake of arginine were not directly affected by the drug. Indomethacin also decreased uridine incorporation in macrophages. The effect of indomethacin on the induction of other enzymes (i.e. arginase) was weaker. © 2001 Elsevier Science Inc.SCOPUS: ar.jinfo:eu-repo/semantics/publishe

Effects of dexamethasone on macrophage migration inhibitory factor production in sepsis.

Macrophage migration inhibitory factor (MIF) is a proinflammatory cytokine that plays a major role in the pathogenesis of sepsis. Some studies have indicated that glucocorticoids increase MIF production in physiological conditions. The goal of this study was to determine whether glucocorticoid treatment also upregulates MIF production in sepsis. Male NMRI mice (6-10 weeks old) underwent laparotomy, proximal ligation of the cecum, and double perforation with a 19-gauge needle (cecal ligation and puncture). Mice were randomly treated with saline (control) or dexamethasone at doses of 0.1, 1, or 10 mg/kg ip. At 6 or 18 h postoperatively, 10 mice per group were euthanized; and blood, peritoneal fluid, liver, lung, kidney, and heart tissue samples were retrieved. MIF, IL-6, TNF-alpha, and IL-10 were measured by enzyme-linked immunosorbent assay. Sepsis induced by cecal ligation and puncture produced a marked increase in MIF and cytokine levels in plasma and peritoneal fluid. Treatment with dexamethasone 10 mg/kg decreased MIF levels in plasma after 18 h, but there was no effect of dexamethasone on MIF production locally in the peritoneal cavity or in the liver, lungs, heart, or kidneys. We conclude that glucocorticoid treatment does not upregulate MIF production in sepsis.Journal ArticleSCOPUS: ar.jinfo:eu-repo/semantics/publishe

Chicken cystatin stimulates nitric oxide release from interferon-γ- activated mouse peritoneal macrophages via cytokine synthesis

Cystatins are natural tight-binding, reversible inhibitors of cysteine proteases. We have shown that cystatins also stimulate nitric oxide (NO) production by interferon-γ-activated mouse peritoneal macrophages [Verdot, L. Lalmanach, G. Vercruysse, V. Hartman, S. Lucius, R. Hoebeke, J. Gauthier F. and Vray, B. (1996) J. Biol. Chem. 271, 28077-28081]. The present study was undertaken to further document this new function. Macrophages activated with interferon-γ and then stimulated with interferon-γ plus chicken cystatin generated increased amounts of NO in comparison with macrophages only activated with interferon-γ. Interferon-γ-activated macrophages must be incubated with chicken cystatin for at least 8 h to upregulate NO production. NO induction was due to increased inducible nitric oxide synthase protein synthesis. Macrophages incubated with chicken cystatin alone or with interferon-γ plus chicken cystatin produced increased amounts of both tumor necrosis factor α and interleukin 10. The addition of recombinant murine tumor necrosis factor α alone or in combination with recombinant murine interleukin-10 mimicked the effect of chicken cystatin. The addition of neutralizing anti-(tumor necrosis factor α) antibodies reduced sharply NO production by chicken cystatin/ interferon-γ-activated mouse peritoneal macrophages. Taken together, these data suggest that chicken cystatin induces the synthesis of tumor necrosis factor α and interleukin 10. In turn, these two cytokines stimulate the production of NO by interferon-γ-activated macrophages. The findings point to a new relationship between cystatins, cytokines, inflammation and the immune response.SCOPUS: ar.jinfo:eu-repo/semantics/publishe

Development and characterization of nuclear microsatellite markers for the African walnut Coula edulis Baill (Coulaceae)

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Polysaccharides extracted from Plantago palmata Hook.f. leaves induce nitric oxide and tumor necrosis factor-alfa production by interferon-gamma-activated macrophages

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Polysaccharides extracted from the leaves of Plantago palmata Hook.f. induce nitric oxide and tumor necrosis factor-alpha production by interferon-gamma-activated macrophages.

Ethnopharmacological data from eastern African traditional uses of Plantago palmata leaves suggest that some therapeutical activities could be dependent on their content in polysaccharides (PS). To further investigate immunomodulatory properties of these PS, they were extracted in water from leaves by maceration either at (i) 50 degrees C without filtration (PS50); (ii) 50 degrees C and filtration (PS50F); (iii) 100 degrees C, without filtration (PS100); or 100 degrees C and filtration (PS100F). The extract PS50 was further fractionated by high performance liquid chromatography (gel permeation chromatography) in three fractions namely F1, F2, and F3. The immunomodulatory properties of these four crude extracts and PS50 fractions were investigated by the measurement of nitric oxide (NO), tumor necrosis factor-alpha (TNF-alpha), and interleukin-10 (IL-10) production using interferon gamma-(IFN-gamma)-activated macrophages and non-activated macrophages as control. Non-activated J774 cell line macrophages, treated with any of the PS extracts, did produce neither NO, nor TNF-alpha, nor IL-10. In contrast, IFN-gamma-activated J774 macrophages synergized with PS50, but not with the three other crude extracts, to produce both NO and TNF-alpha, but not IL-10. Immunomodulatory effects due to traces of lipopolysaccharides (LPS) in PS extracts and fractions were ruled out by the use of macrophages from C3H/Hej mice known to be very low responders to LPS and similar results were obtained. In addition, F2 fraction from PS50 was particularly active in enhancing NO and TNF-alpha (but not IL-10) production by IFN-gamma-activated C3H/Hej macrophages. These results suggest that PS from P. palmata leaves possess immunomodulatory properties by stimulating NO and TNF-alpha production by activated macrophages.Journal ArticleResearch Support, Non-U.S. Gov'tSCOPUS: ar.jinfo:eu-repo/semantics/publishe

Action of chloroquine on nitric oxide production and parasite killing by macrophages

Chloroquine is known to inhibit several functions of macrophages, but its effect on the nitric oxide (NO)-dependent parasite killing capacity of macrophages has not been documented. NO synthesis by interferon-γ-induced mouse and casein-elicited rat macrophages was significantly and irreversibly inhibited by chloroquine. The activity of the inducible NO synthase was not directly altered, but previous incubation of macrophages with chloroquine decreased it. Chloroquine did not alter arginase activity or arginine uptake. NADPH diaphorase activity, an indicator of NO synthase was impaired. Western blotting showed that inducible NO synthase synthesis was blocked by chloroquine. The blocking of NO formation by chloroquine resulted in increased infection of mouse peritoneal macrophages by Trypanosoma cruzi (T. cruzi). This suggests that chloroquine decreases NO formation by macrophages by inhibiting the induction of NO synthase. The findings are further evidence that NO is involved in the anti-parasitic response of macrophages. Copyright (C) 1998 Elsevier Science B.V.SCOPUS: ar.jinfo:eu-repo/semantics/publishe

Polysaccharides extracted from Plantago palmata induce nitric oxide production by IFN--activated mouse peritoneal macrophages

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Transfection of Trypanosoma cruzi with Host CD40 Ligand Results in Improved Control of Parasite Infection

We have previously shown that infection by Trypanosoma cruzi, a parasitic protozoan, is reduced by injection of CD40 ligand (CD40L)-transfected 3T3 fibroblasts (D. Chaussabel, F. Jacobs, J. de Jonge, M. de Veerman, Y. Carlier, K. Thielemans, M. Goldman, and B. Vray, Infect. Immun. 67:1929-1934, 1999). This prompted us to transfect T. cruzi with the murine CD40L gene and to study the consequences of this transfection on the course of infection. For this, epimastigotes (Y strain) were electroporated with the pTEX vector alone or the pTEX-CD40L construct, and transfected cells were selected for their resistance to Geneticin G418. Then strain Y-, pTEX-, and pTEX-CD40L-transfected epimastigotes were transformed by metacyclogenesis into mammalian infective forms called Y, YpTEX, and YpTEX-CD40L trypomastigotes. Transfection of the CD40L gene and expression of the CD40L protein were assessed by reverse transcription-PCR and Western blot analysis. The three strains of parasites were infective in vitro for mouse peritoneal macrophages. When organisms were inoculated into mice, a very low level of parasitemia and no mortality were seen with the YpTEX-CD40L strain compared to the Y and YpTEX strains. Furthermore, the proliferative capacity and the secretion of gamma interferon were both preserved in spleen cells (SCs) from YpTEX-CD40L-infected mice but not with SCs from Y- and YpTEX-infected mice. These results suggest that the CD40L produced by transfected T. cruzi is involved in the modulation of an antiparasite immune response. Moreover, mice surviving YpTEX-CD40L infection resisted a challenge infection with the wild-type strain. Taken together, our data demonstrate the feasibility of generating a T. cruzi strain expressing a bioactive host costimulatory molecule that counteracts the immunodeficiency induced by the parasite during infection and enhances protective immunity against a challenge infection