降植烷通过内质网应激诱导大鼠巨噬细胞自噬

Pristane induces autophagy in rat macrophages through endoplasmic reticulum stress

目的探讨佐剂降植烷诱导自噬增强的确切机制。方法构建降植烷刺激的大鼠巨噬细胞系模型;Western blotting检测细胞模型能量代谢分子腺苷酸活化蛋白激酶(AMPK)、哺乳动物雷帕霉素靶蛋白(mTOR)及内质网应激通路真核起始因子2α(eIF2α)和肌醇依赖酶1α(IRE1α)的表达与活化,及转录因子EB(TFEB)的表达及入核情况;采用二硫苏糖醇(DTT)、4-苯基丁酸(4-PBA)调控细胞内质网应激水平并观察对mTOR表达和细胞自噬的影响。结果降植烷刺激的NR8383细胞模型中,eIF2α在刺激0.5 h活化,mTOR表达在刺激后1、3 h较对照组(0 h)显著降低,AMPK及IRE1α无明显变化。降植烷刺激的NR8383细胞模型的mTOR表达下调,在4-PBA干预时表达回升,而增强的LC3-II表达受到抑制;在DTT干预细胞模型时,mTOR表达则进一步下调,同时LC3-II表达则更高。降植烷诱导细胞的TFEB表达升高并活化入核。结论降植烷可能通过诱导内质网应激实现巨噬细胞自噬增强。

Objective To investigate the mechanism of pristane inducing autophagy in macrophages.Methods Pristane was used to stimulate NR8383,a rat macrophage cell line.The changes in signaling pathways of AMPK,mTOR,and endoplasmic reticulum(ER)stress pathways including eIF2αand IRE1αin the cell model,as well as the expression of transcriptional factor TFEB and its translocation to the nucleus,were detected by using Western blotting.ER stress pathways were intervened by using an inducer DTT or an inhibitor 4-PBA to determin its effect on mTOR expression and autophay.Results In pristane-stimulated NR8383 cell model,ER stress pathway eIF2αwas activated at 0.5 h after stimulation,and then mTOR expression was decreased at 1 and 3 h after stimulation.There was no change for AMPK and IRE1αpathways.With 4-PBA treatment,pristane-reduced mTOR expression and increased LC3-II were reversed,while with DTT treatment,mTOR expression decreased and LC3-II expression increased even more.Pristane induced the expression and activation of TFEB in NR8383 cells.Conclusion Pristane induces ER stress and leads to autophagy enhancement in rat macrophages.