School of Basic Medicine, Henan University of Traditional Chinese Medicine, Zhengzhou 450008, China.
Molecules. 2012 May 30;17(6):6557-68. doi: 10.3390/molecules17066557.
Radix Glycyrrhizae polysaccharide (GP), the most important component of Radix Glycyrrhizae, has been reported to have many immunopharmacological activities. However, the mechanism by which GP affects dendritic cells (DCs) has not been elucidated. In this study, we investigated the effect of GP on murine bone marrow-derived DCs and the potential pathway through which GP exerts this effect. Mononuclear cells (MNCs) were isolated from murine bone marrow and induced to become DCs by culturing with GM-CSF and IL-4. Six days later, DCs were divided into three groups: control group, GP group and LPS group. After 48 h of treatment, phenotypic figures and antigen uptake ability were determined by FACS analysis. The proliferation of DC-stimulated allogenic CD3+ T cells was detected by WST-1. IL-12 p70 and IFN-γ, which are secreted by DCs and CD3+ T cells respectively, were quantified by ELISA. Additionally, IL-12 p40 mRNA expression was determined by real-time PCR. Alterations in TLR4-related signaling pathways were examined by performing an antibody neutralization experiment. Treatment of DCs with GP resulted in the enhanced expression of the cell surface molecules CD80, CD86 and MHC I-A/I-E. GP also increased the production of IL-12 p70 by DCs in a time-dependent manner. The endocytosis of FITC-dextran by DCs was suppressed by GP administration. Furthermore, GP-treated DCs enhanced both the proliferation and IFN-γ secretion of allogenic CD3+ T cells. Finally, the effects of GP on DCs were partially reduced by using inhibitors of TLR4, NF-κB, p38 MAPK or JNK. In conclusion, GP can induce the maturation of DCs, and does so, in part, by regulating a TLR4-related signaling pathway.
甘草多糖（GP）是甘草的主要成分之一，具有多种免疫药理学活性。然而，GP 影响树突状细胞（DC）的机制尚未阐明。在本研究中，我们研究了 GP 对小鼠骨髓来源的 DC 的影响，以及 GP 发挥这种作用的潜在途径。从鼠骨髓中分离出单核细胞（MNC），并通过与 GM-CSF 和 IL-4 共培养诱导成为 DC。6 天后，将 DC 分为三组：对照组、GP 组和 LPS 组。处理 48 小时后，通过 FACS 分析测定表型和抗原摄取能力。通过 WST-1 检测 DC 刺激的同种异体 CD3+T 细胞的增殖。通过 ELISA 定量检测 DC 和 CD3+T 细胞分别分泌的 IL-12 p70 和 IFN-γ。此外，通过实时 PCR 测定 IL-12 p40 mRNA 的表达。通过进行抗体中和实验来检测 TLR4 相关信号通路的改变。结果表明，GP 处理可增强 DC 表面分子 CD80、CD86 和 MHC I-A/I-E 的表达。GP 还可时间依赖性地增加 DC 中 IL-12 p70 的产生。GP 给药可抑制 DC 摄取 FITC-右旋糖酐。此外，GP 处理的 DC 增强了同种异体 CD3+T 细胞的增殖和 IFN-γ 分泌。最后，使用 TLR4、NF-κB、p38 MAPK 或 JNK 的抑制剂部分减少了 GP 对 DC 的作用。总之，GP 可诱导 DC 成熟，其部分机制是通过调节 TLR4 相关信号通路。
