Arctigenin alleviates ER stress via activating AMPK
Arctigenin alleviates ER stress via activating AMPK
复制标题
牛蒡甙元通过激活 AMPK 缓解 ER 应激
DOI：
10.1038/aps.2012.60
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发表时间：
2012-07-01
影响因子：
8.2
通讯作者：
Yu, Qiang
中科院分区：
文献类型：
--
作者：
Gu, Yuan;Sun, Xiao-xiao;Yu, Qiang
目的：研究牛蒡苷元（arctigenin，ATG）对内质网应激的保护作用及其机制。使用MTT测定法测量细胞活力。PCR和Western blotting分析基因和蛋白表达。通过RNA干扰（RNAi）实现CaMKKβ、LKB 1和AMPKα1基因的沉默。结果：ATG（2.5、5和10 μmol/L）浓度依赖性地抑制ER应激诱导剂Brefeldin A（100 nmol/L）诱导的细胞死亡和未折叠蛋白反应（UPR）。ATG（1、5和10 μmol/L）通过抑制mTOR-p70 S6 K信号通路和eEF 2活性，显著抑制细胞蛋白质合成，而AMPKα1的RNAi沉默可部分逆转上述作用。ATG（1-50 μmol/L）通过抑制复合物I介导的呼吸作用，降低细胞内ATP水平并激活AMPK。用AMPK抑制剂化合物C（25 μmol/L）预处理细胞可解除ATG对ER应激的抑制作用。结论：ATG是一种有效的内质网应激缓解剂，其作用机制可能是通过激活AMPK，减少蛋白质翻译，降低内质网负荷，从而保护INS-1 β细胞免受内质网应激。
Aim:To investigate the protective effects of arctigenin (ATG), a phenylpropanoid dibenzylbutyrolactone lignan from Arctium lappa L (Compositae), against ER stress in vitro and the underlying mechanisms.Methods:A cell-based screening assay for ER stress regulators was established. Cell viability was measured using MTT assay. PCR and Western blotting were used to analyze gene and protein expression. Silencing of the CaMKKβ, LKB1, and AMPKα1 genes was achieved by RNA interference (RNAi). An ATP bioluminescent assay kit was employed to measure the intracellular ATP levels.Results:ATG (2.5, 5 and 10 μmol/L) inhibited cell death and unfolded protein response (UPR) in a concentration-dependent manner in cells treated with the ER stress inducer brefeldin A (100 nmol/L). ATG (1, 5 and 10 μmol/L) significantly attenuated protein synthesis in cells through inhibiting mTOR-p70S6K signaling and eEF2 activity, which were partially reversed by silencing AMPKα1 with RNAi. ATG (1-50 μmol/L) reduced intracellular ATP level and activated AMPK through inhibiting complex I-mediated respiration. Pretreatment of cells with the AMPK inhibitor compound C (25 μmol/L) rescued the inhibitory effects of ATG on ER stress. Furthermore, ATG (2.5 and 5 μmol/L) efficiently activated AMPK and reduced the ER stress and cell death induced by palmitate (2 mmol/L) in INS-1 β cells.Conclusion:ATG is an effective ER stress alleviator, which protects cells against ER stress through activating AMPK, thus attenuating protein translation and reducing ER load.