果糖致HepG2细胞脂质沉积及ATF-4敲除的保护作用

Protection effect of ATF-4 knockdown on fructose-induced steatosis in HepG2 cells

目的探讨果糖对肝细胞脂质沉积的影响及激活转录因子4(ATF-4)敲减的干预作用。方法转染针对HepG细胞ATF-4的siRNA,根据处理将细胞分为4组:对照组(C)、高果糖组(F)、高果糖+阴性对照组(F+NC)、高果糖+ATF-4 siRNA组(F+ATF-4-),检测各组肝脏脂质从头合成上游转录因子及内质网应激标志物的基因水平,并检测下游脂质合成的关键酶类的蛋白表达水平。结果与C组比较,F组SREBP-1c、Ch REBP及GRP78、CHOP的基因表达增加,ATF-4敲减降低了上述基因的表达水平(均P<0.01);与C组比较,F组ACC、FAS、SCD-1的蛋白表达增加(均P<0.01),而ATF-4敲减降低了ACC、FAS、SCD-1的蛋白表达(均P<0.01)。结论 ATF-4敲减通过下调脂质从头合成改善果糖诱导的HepG2细胞脂质沉积,提示ATF-4对脂质从头合成具有调节作用。

Objective To investigate he intervention effect of knockdown of activating transcription factor4（ATF-4）on fructose-induced lipid accumulation in liver cells. Methods Hep G2 cells were divided into the con-trol group（C）,high fructose group（F）,high-fructose＋negative control group（F＋NC）and high-fructose＋ATF-4 si RNA group（F＋ ATF-4-）. The m RNA level of gens of the upstream transcriptional factors and ERS markers wasdetected. The protein level of ACC,FAS and SCD-1 was also detected. Results Compared with group C,them RNA expression of SREBP-1 c,Ch REBP,GRP78 and CHOP was increased（P〈0.01）,while ATF-4 knock-down decreased the expression of the above genes（P〈0.01,respectively）. Compared with group C,the proteinexpression of ACC,FAS and SCD-1 was increased in group F（P〈0.01,respectively）. While ATF-4 knockdowndecreased the protein expression of ACC,FAS and SCD-1. Conclusions ATF-4 knockdown can improve the lip-id steatosis induced by fructose through down-regulating lipid lipogenesis,indicating ATF-4 possesses a regulatoryeffect on lipogenesis.