title: Glycyrrhizin enhances interleukin-12 production in peritoneal macrophages.
abstract: Interleukin-12 (IL-12) is a monocyte/macrophage-derived cytokine that plays a prominent role in the development of T helper type 1 (Th1) cell-mediated immune responses. Glycyrrhizin (GL), an aqueous extract of liquorice root, used as Chinese medicine, is known to have various immunomodulating activities. In this study, GL showed a dose-dependent priming effect on lipopolysaccharide (LPS)-induced IL-12 p40 and IL-12 p70 (heterodimer of p40 and p35) protein production by peritoneal macrophages (PM). The maximal effect was observed when GL was intraperitoneally administered 12 hr before the PM were harvested and stimulated in vitro with LPS. The increases in IL-12 p70 and p40 protein production were primarily due to up-regulated transcription of IL-12 p35 and p40 messenger RNAs (mRNAs), as demonstrated by RNase protection assay. The augmentation of IL-12 p40 mRNA expression induced by GL pretreatment was associated with increased NF-kappaB activation. Moreover, GL exhibited the same priming effect on IL-12 production in interferon-gamma knockout (IFN-gamma-/-) mice. The production of granulocyte-macrophage colony-stimulating factor (GM-CSF) was not induced at any time point after GL pretreatment. These findings demonstrated the ability of GL to enhance LPS-induced IL-12 production by peritoneal macrophages, and indicated that the priming effect of GL on IL-12 production was independent of both IFN-gamma and GM-CSF.
authors: Department of Microbiology, Yamanashi Medical University, Yamanashi, Centre for Experimental Medicine, Institute of Medical Science, University of Tokyo, Tokyo, Japan.
authors: J H
authors: JH
authors: Dai
authors: Y
authors: Y
authors: Iwatani
authors: T
authors: T
authors: Ishida
authors: H
authors: H
authors: Terunuma
authors: H
authors: H
authors: Kasai
authors: Y
authors: Y
authors: Iwakula
authors: H
authors: H
authors: Fujiwara
authors: M
authors: M
authors: Ito
mesh_terms: D000818:Animals; D000890:Anti-Infective Agents / Q000276:immunology*; D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000276:immunology*; D018929:Cell Culture Techniques; D004306:Dose-Response Relationship, Immunologic; D005260:Female; D019695:Glycyrrhizic Acid / Q000276:immunology*; D016178:Granulocyte-Macrophage Colony-Stimulating Factor / Q000276:immunology; D007371:Interferon-gamma / Q000276:immunology; D018664:Interleukin-12 / Q000096:biosynthesis*; D008070:Lipopolysaccharides / Q000276:immunology; D017737:Macrophages, Peritoneal / Q000276:immunology*; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D016328:NF-kappa B / Q000378:metabolism; D010533:Peritoneal Lavage; D012333:RNA, Messenger / Q000235:genetics; D014158:Transcription, Genetic; D015854:Up-Regulation / Q000276:immunology
chemical_list: D000890:Anti-Infective Agents; D000894:Anti-Inflammatory Agents, Non-Steroidal; D008070:Lipopolysaccharides; D016328:NF-kappa B; D012333:RNA, Messenger; D018664:Interleukin-12; D019695:Glycyrrhizic Acid; D007371:Interferon-gamma; D016178:Granulocyte-Macrophage Colony-Stimulating Factor