Park Eun-Jung, Lee Hae-Jeung
Department of Food and Nutrition, College of BioNano Technology, Gachon University, Seongnam 13120, Korea.
Institute for Aging and Clinical Nutrition Research, Gachon University, Seongnam 13120, Korea.
Nutr Res Pract. 2020 Oct;14(5):453-462. doi: 10.4162/nrp.2020.14.5.453. Epub 2020 Jun 8.
BACKGROUND/OBJECTIVES: (PG), an oriental herbal medicine, has been known to improve liver function, and has both anti-inflammatory and antimicrobial properties. However, little is known about the immune-enhancing effects of PG and its mechanism. In this study, we aimed to investigate whether fermented PG extract (FPGE), which has increased platycodin D content, activates the immune response in a murine macrophage cell line, RAW 264.7.
MATERIALS/METHODS: Cell viability was determined by Cell Counting Kit-8 assay and the nitric oxide (NO) levels were measured using Griess reagent. Cytokine messenger RNA levels of were monitored by quantitative reverse transcription polymerase chain reaction. To investigate the molecular mechanisms underlying immunomodulatory actions of FPGE in RAW 264.7 cells, we have conducted luciferase reporter gene assay and western blotting.
We found that FPGE treatment induced macrophage cell proliferation in a dose-dependent manner. FPGE also modulated the expression of NO and pro-inflammatory cytokines, such as tumor necrosis factor-α, interleukin (IL)-1β, and IL-6. The activation and phosphorylation levels of nuclear factor kappa B (NF-κB) were increased by FPGE treatment. Moreover, 5-aminoimidazole-4-carboxamide ribonucleotide, an activator of AMP-activated kinase (AMPK), significantly reduced both lipopolysaccharides- and FPGE-induced NF-κB reporter gene activity.
Taken together, our findings suggest that FPGE may be a novel immune-enhancing agent acting via AMPK-NF-κB signaling pathway.
背景/目的：桔梗（PG）是一种东方草药，已知其可改善肝功能，且具有抗炎和抗菌特性。然而，关于PG的免疫增强作用及其机制却知之甚少。在本研究中，我们旨在探究发酵桔梗提取物（FPGE）（其桔梗皂苷D含量有所增加）是否能激活小鼠巨噬细胞系RAW 264.7中的免疫反应。
材料/方法：通过细胞计数试剂盒-8法测定细胞活力，使用格里斯试剂测量一氧化氮（NO）水平。通过定量逆转录聚合酶链反应监测细胞因子信使核糖核酸水平。为了探究FPGE在RAW 264.7细胞中免疫调节作用的分子机制，我们进行了荧光素酶报告基因检测和蛋白质印迹分析。
我们发现FPGE处理以剂量依赖性方式诱导巨噬细胞增殖。FPGE还调节了NO以及促炎细胞因子如肿瘤坏死因子-α、白细胞介素（IL）-1β和IL-6的表达。FPGE处理可提高核因子κB（NF-κB）的激活和磷酸化水平。此外，AMP激活的蛋白激酶（AMPK）的激活剂5-氨基咪唑-4-甲酰胺核糖核苷酸显著降低了脂多糖和FPGE诱导的NF-κB报告基因活性。
综上所述，我们的研究结果表明FPGE可能是一种通过AMPK-NF-κB信号通路发挥作用的新型免疫增强剂。
