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Mediators of Inflammation
Volume 2015, Article ID 372931, 12 pages
http://dx.doi.org/10.1155/2015/372931
Research Article

Glycyrrhizic Acid Promotes M1 Macrophage Polarization in Murine Bone Marrow-Derived Macrophages Associated with the Activation of JNK and NF-κB

Key Laboratory of Animal Molecular Nutrition of Education of Ministry, College of Animal Sciences, Zhejiang University, 866 Yu Hang Tang Road, Hangzhou, Zhejiang 310058, China

Received 7 July 2015; Revised 10 October 2015; Accepted 15 October 2015

Academic Editor: Yona Keisari

Copyright © 2015 Yulong Mao et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

The roots and rhizomes of Glycyrrhiza species (licorice) have been widely used as natural sweeteners and herbal medicines. The aim of this study is to investigate the effect of glycyrrhizic acid (GA) from licorice on macrophage polarization. Both phenotypic and functional activities of murine bone marrow-derived macrophages (BMDMs) treated by GA were assessed. Our results showed that GA obviously increased the cell surface expression of CD80, CD86, and MHCII molecules. Meanwhile, GA upregulated the expression of CCR7 and the production of TNF-α, IL-12, IL-6, and NO (the markers of classically activated (M1) macrophages), whereas it downregulated the expression of MR, Ym1, and Arg1 (the markers of alternatively activated (M2) macrophage). The functional tests showed that GA dramatically enhanced the uptake of FITC-dextran and E. coli K88 by BMDMs and decreased the intracellular survival of E. coli K88 and S. typhimurium. Moreover, we demonstrated that JNK and NF-κB activation are required for GA-induced NO and M1-related cytokines production, while ERK1/2 pathway exhibits a regulatory effect via induction of IL-10. Together, these findings indicated that GA promoted polarization of M1 macrophages and enhanced its phagocytosis and bactericidal capacity. The results expanded our knowledge about the role of GA in macrophage polarization.