掌叶半夏凝集素蛋白刺激巨噬细胞的致炎作用研究

Pro-inflammatory mechanism of lectin from Pinellia pedatisecta on macrophage

为探索掌叶半夏凝集素蛋白(PPL)刺激巨噬细胞诱导炎症的作用与炎症小体NLRP3的相关性。采用凝胶色谱纯化掌叶半夏凝集素蛋白并采用SDS-PAGE凝胶电泳分析其纯度;采用ELISA法以IL-1β为指标考察PPL刺激巨噬细胞释放炎症因子的影响;采用荧光探针DCFH-DA荧光酶标仪检测PPL刺激巨噬细胞后活性氧ROS的水平变化;以ROS抑制剂NAC(N-乙酰半胱氨酸)预处理巨噬细胞,考察PPL刺激ROS的过量生成与炎症因子IL-1β大量释放的相关性;采用Western Blot方法检测PPL对炎症小体生成相关的Caspase-1 p20,NLRP3,TXNIP,ASC等蛋白的表达水平变化。结果显示分离纯化的PPL达到电泳纯;PPL刺激巨噬细胞后引起ROS过量释放,引起强烈的氧化应激反应,胞内炎症因子IL-1β含量显著升高;NAC可抑制PPL导致的ROS过量生成,且IL-1β释放也显著降低。同时PPL可诱导胞内Caspase-1 p20,NLRP3,ASC蛋白表达升高,TXNIP表达显著降低。研究结果表明,PPL刺激巨噬细胞可导致强烈的氧化应激反应,同时能够激活炎症小体NLRP3,导致IL-1β大量生成释放,即PPL能够通过ROS-TXNIP-NLRP3-IL-1β信号通路促进IL-1β的成熟和分泌,导致炎症级联反应。

To investigate the mechanism of lectin from PineUia pedatisecta（PPL） on macrophage-induced inflammation and its asso- ciation with inflammatory corpuscles NLRP3. Lectin from P. pedatisecta was isolated and purified by gel chromatography, and its purity was analyzed by using SDS-PAGE gel electrophoresis. ELISA was used to investigate the effect of PPL on inflammatory cytokines re- leased by macrophages, with IL-1β as indicators ; and fluorescence probe DCFH-DA fluorometer was used to determine changes in active oxygen ROS of macrophages after application of lectin from P. pedatisecta. RAW264. 7 cells were pre-treated with ROS inhibitor N-ace- tylcysteine （NAC） to investigate the effect on ROS and the release of inflammatory factor IL-lfl from macrophages to research the rela- tionship between them. The protein levels of NLRP3, Caspase-1 p20, ASC and TXNIP were determined by Western blot. The results showed that isolated and purified PPL could reach electrophoretic purity; PPL stimulated macrophages and induced the excessive re- lease of ROS, leading to strong oxidative stress reaction, and the levels of intracellular inflammatory factorsIL-1β were significantly in-creased. NAC could inhibit PPL-induced ROS excessive production and significantly reduce the release of IL-1,8. In addition, PPL could induce the increase in protein expression levels of Caspase-1 p20, NLRP3 and ASC, and significantly reduce TXNIP expression. The results showed that PPL could cause a strong oxidative stress response by stimulating macrophages, activate inflammatory corpus- cles NLRP3, and result in large amount of IL-1,8 release. That is, PPL could lead to inflammatory cascade reaction by promoting the maturation and secretion of IL-1β through ROS-TXNIP-NLRP3-IL-1β signaling pathway.