Xiangya School of Public Health, Central South University, Changsha, 410128, China.
Nutrients. 2019 Nov 15;11(11):2794. doi: 10.3390/nu11112794.
Punicalagin, a hydrolysable tannin of pomegranate juice, exhibits multiple biological effects, including inhibiting production of pro-inflammatory cytokines in macrophages. Autophagy, an intracellular self-digestion process, has been recently shown to regulate inflammatory responses. In this study, we investigated the anti-inflammatory potential of punicalagin in lipopolysaccharide (LPS) induced RAW264.7 macrophages and uncovered the underlying mechanisms. Punicalagin significantly attenuated, in a concentration-dependent manner, LPS-induced release of NO and decreased pro-inflammatory cytokines TNF-α and IL-6 release at the highest concentration. We found that punicalagin inhibited NF-κB and MAPK activation in LPS-induced RAW264.7 macrophages. Western blot analysis revealed that punicalagin pre-treatment enhanced LC3II, p62 expression, and decreased Beclin1 expression in LPS-induced macrophages. MDC assays were used to determine the autophagic process and the results worked in concert with Western blot analysis. In addition, our observations indicated that LPS-induced releases of NO, TNF-α, and IL-6 were attenuated by treatment with autophagy inhibitor chloroquine, suggesting that autophagy inhibition participated in anti-inflammatory effect. We also found that punicalagin downregulated FoxO3a expression, resulting in autophagy inhibition. Overall these results suggested that punicalagin played an important role in the attenuation of LPS-induced inflammatory responses in RAW264.7 macrophages and that the mechanisms involved downregulation of the FoxO3a/autophagy signaling pathway.
鞣花酸是石榴汁中的一种可水解单宁，具有多种生物学效应，包括抑制巨噬细胞中促炎细胞因子的产生。自噬是一种细胞内自我消化的过程，最近已被证明可调节炎症反应。在这项研究中，我们研究了鞣花酸在脂多糖（LPS）诱导的 RAW264.7 巨噬细胞中的抗炎潜力，并揭示了其潜在的机制。鞣花酸以浓度依赖性方式显著减弱 LPS 诱导的 RAW264.7 巨噬细胞中 NO 的释放，并在最高浓度下降低促炎细胞因子 TNF-α和 IL-6 的释放。我们发现，鞣花酸抑制 LPS 诱导的 RAW264.7 巨噬细胞中 NF-κB 和 MAPK 的激活。Western blot 分析显示，鞣花酸预处理增强了 LPS 诱导的巨噬细胞中 LC3II、p62 的表达，并降低了 Beclin1 的表达。MDC 测定用于确定自噬过程，结果与 Western blot 分析一致。此外，我们的观察表明，自噬抑制剂氯喹处理可减轻 LPS 诱导的 NO、TNF-α和 IL-6 的释放，表明自噬抑制参与了抗炎作用。我们还发现，鞣花酸下调 FoxO3a 的表达，导致自噬抑制。总的来说，这些结果表明，鞣花酸在减弱 LPS 诱导的 RAW264.7 巨噬细胞炎症反应中发挥了重要作用，其机制涉及下调 FoxO3a/自噬信号通路。
