黄曲霉毒素B1诱导MEK/ERK/ROS介导的巨噬细胞自噬反应

摘要

为研究黄曲霉毒素B1(AFB1)能否诱导细胞自噬,并初步探讨其可能的作用机制.利用免疫荧光、酶标仪检测、免疫印迹等技术检测经AFB1处理过的细胞的自噬水平、相关蛋白的表达量以及活性氧(Reac-tive oxygen species,ROS)的产生情况.结果表明:AFB1能够引起RAW264.7细胞和Hela细胞的自噬反应,并且该自噬为完全自噬.AFB1诱导的小鼠单核巨噬细胞RAW264.7自噬是依赖细胞外信号调节激酶(Extra-cellular signal-regulated kinase,ERK)途径发生的,并受ROS的调节.此外,发现AFB1诱导ROS产生呈浓度依赖性,而ROS抑制剂同时抑制了ROS和自噬发生,但自噬抑制剂并没有有效地抑制ROS的产生,表明ROS处于AFB1诱导自噬的上游,对自噬起到调节作用.这表明AFB1诱导的自噬现象在细胞中普遍存在,而自噬作为机体的免疫机制,在抵抗AFB1毒力侵染的过程中发挥重要作用.%To explore whether aflatoxin B1 (AFB1) can induce autophagy in macrophages and what are the possible mechanisms and functions of autophagy,we used immunofluorescence staining,western blot,microplate reader and other techniques to detect the levels of autophagy,quantified the expressions of proteins and molecules related with autophagy,and more importantly detected the abilities of ROS production from RAW264.7 cells,which was treated with AFB1.The results showed that RAW264.7 cells and Hela cells could produce autophagy induced by AFB1.Furthermore,AFBl-induced autophagy was a complete process.Interestingly,autophagy production induced by AFB1 via extracellular signal-regulated kinase (ERK)-dependent pathway and was regulated by reactive oxygen species (ROS).In addition,we found that AFB1 induced the prodution of reactive oxygen species (ROS) in a dose-dependent manner,and especially,inhibition of ROS prevented autophagy process,indicating that ROS generation occurred upstream of AFB1-induced autophagy.Therefore,our study showed that AFB 1 induced autophagy generally existed in mammalian cells.So autophagy played an important role in resisting AFB 1 infection.These results will lay a solid foundation for further study on mechanism of aflatoxin.