Wu Lehao, Fan Yunpeng, Fan Chao, Yu Yang, Sun Lei, Jin Yu, Zhang Yan, Ye Richard D
School of Pharmacy, Shanghai Jiao Tong University, Shanghai 200240, China.
Engineering Research Center of Pharmaceutical Process Chemistry, Ministry of Education, School of Pharmacy, East China University of Science and Technology, Shanghai 200237, China.
Eur J Pharmacol. 2017 Apr 15;801:46-53. doi: 10.1016/j.ejphar.2017.02.049. Epub 2017 Mar 2.
The effects of licocoumarone (LC) isolated from Glycyrrhiza uralensis were studied in LPS-stimulated RAW 264.7 macrophages. Our study demonstrated that LC dose-dependently attenuated LPS-induced NO production by down-regulating iNOS expression. Additionally, the treatment with LC inhibited LPS-induced expression of cytokines including IL-1β, IL-6 and IL-10, but not TNF-α, at both mRNA and protein levels. Similar suppressive effects of LC were observed on LPS-stimulated murine peritoneal macrophages as well. Furthermore, LC significantly reduced LPS-stimulated NF-κB activation by inhibition of IκBα degradation and p65 phosphorylation. The results from NF-κB-luc reporter gene assay further support the inhibitory effect of LC on NF-κB activation. Further studies showed that LC also interfered with the MAPKs and STAT3 signaling pathways, which are typical inflammatory signaling pathways triggered by LPS. Taken together, these results show that LC attenuates LPS-induced cytokine gene expression in RAW 264.7 macrophages through mechanisms that involve NF-κB, MAPKs and STAT3 signaling pathways, but the pattern of inhibition differs from that of a global immunosuppresant. Our study indicates that LC is a functional constituent of Glycyrrhiza uralensis with potential implications in infectious and immune-related diseases.
研究了从甘草中分离出的甘草香豆素（LC）对脂多糖（LPS）刺激的RAW 264.7巨噬细胞的影响。我们的研究表明，LC通过下调诱导型一氧化氮合酶（iNOS）的表达，剂量依赖性地减弱LPS诱导的一氧化氮（NO）生成。此外，LC处理在mRNA和蛋白质水平上均抑制LPS诱导的包括白细胞介素-1β（IL-1β）、白细胞介素-6（IL-6）和白细胞介素-10（IL-10）在内的细胞因子表达，但不影响肿瘤坏死因子-α（TNF-α）。在LPS刺激的小鼠腹腔巨噬细胞上也观察到了LC类似的抑制作用。此外，LC通过抑制IκBα降解和p65磷酸化，显著降低LPS刺激的核因子-κB（NF-κB）激活。NF-κB荧光素酶报告基因分析结果进一步支持了LC对NF-κB激活的抑制作用。进一步的研究表明，LC还干扰了丝裂原活化蛋白激酶（MAPKs）和信号转导子与转录激活子3（STAT3）信号通路，这两条通路是由LPS触发的典型炎症信号通路。综上所述，这些结果表明，LC通过涉及NF-κB、MAPKs和STAT3信号通路的机制减弱LPS诱导的RAW 264.7巨噬细胞中细胞因子基因的表达，但其抑制模式不同于全身性免疫抑制剂。我们的研究表明，LC是甘草的一种功能性成分，在感染性疾病和免疫相关疾病中具有潜在意义。
