18�-Glycyrrhetinic Acid Triggers Curative Th1 Response and Nitric Oxide Up-Regulation in Experimental Visceral Leishmaniasis Associated with the Activation of NF-�B1
IR@IICB: CSIR-Indian Institute of Chemical Biology, Kolkata
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| Title |
18�-Glycyrrhetinic Acid Triggers Curative Th1 Response and
Nitric Oxide Up-Regulation in Experimental Visceral
Leishmaniasis Associated with the Activation of NF-�B1
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| Creator |
Ukil, Anindita
Biswas, Aruna Das, Tapasi Das, Pijush K |
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| Subject |
Infectious Diseases and Immunology
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| Description |
The efficacy of 18�-glycyrrhetinic acid (GRA), a pentacyclic triterpene belonging to the �-amyrin series of plant origin, was evaluated in experimental visceral leishmaniasis. GRA is reported to have antitumor and immunoregulatory activities, which may be attributable in part to the induction of NO. Indeed, an 11-fold increase in NO production was observed with 20 �M GRA in mouse peritoneal macrophages infected with Leishmania donovani promastigotes. In addition to having appreciable inhibitory
effects on amastigote multiplication within macrophages (IC50, 4.6 �g/ml), complete elimination of liver and spleen parasite burden was achieved by GRA at a dose of 50 mg/kg/day, given three times, 5 days apart, in a 45-day mouse model of visceral leishmaniasis. GRA treatment resulted in reduced levels of IL-10 and IL-4, but increased levels of IL-12, IFN-�, TNF-�, and inducible NO synthase, reflecting a switch of CD4� differentiation from Th2 to Th1. This treatment is likely to activate immunity,
thereby imparting resistance to reinfection. GRA induced NF-�B migration into the nucleus of parasite-infected cells and caused a diminishing presence of I�B in the cytoplasm. The lower level of cytoplasmic I�B� in GRA-treated cells resulted from increased phosphorylation of I�B� and higher activity of I�B kinase (IKK). Additional experiments demonstrated that GRA does not directly affect IKK activity. These results suggest that GRA exerts its effects at some level upstream of IKK in the signaling
pathway and induces the production of proinflammatory mediators through a mechanism that, at least in part, involves induction of NF-�B activation.
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| Date |
2005
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| Type |
Article
PeerReviewed |
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| Format |
application/pdf
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| Identifier |
http://www.eprints.iicb.res.in/346/1/ENDOCRINOLOGY__146(7_)2963%2D2975_;2005[48].pdf
Ukil, Anindita and Biswas, Aruna and Das, Tapasi and Das, Pijush K (2005) 18�-Glycyrrhetinic Acid Triggers Curative Th1 Response and Nitric Oxide Up-Regulation in Experimental Visceral Leishmaniasis Associated with the Activation of NF-�B1. The Journal of Immunology, 175. pp. 1161-1169. |
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| Relation |
http://dx.doi.org/
http://www.eprints.iicb.res.in/346/ |
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