MrgD通过抑制内质网应激调节肝癌细胞脂肪酸代谢

MrgD regulates fat acid metabolism in HepG2 via inhibiting ERS

目的抑制脂肪酸和胆固醇的合成可以有效降低肝癌细胞脂肪积累或脂质代谢,从而抑制肝细胞癌发生。本研究旨在探讨MrgD对肝癌细胞脂肪代谢的作用及机制。方法借助慢病毒包装的重组MrgD表达质粒及MrgD干扰质粒,分别建立稳定性过表达和低表达MrgD的HepG2细胞株。利用游离脂肪酸诱导构建体外细胞脂肪变性模型,通过油红O染色、以及检测脂肪合成相关基因(SREBP2,ACC1)以及ERS标记蛋白(ATF6)水平评估MrgD对肝细胞脂肪代谢的影响和机制。结果成功构建过表达和低表达MrgD的稳转HepG2细胞。在FFA诱导的HepG2细胞脂肪变性模型中,MrgD过表达细胞的脂滴沉积少于对照组;而在低表达MrgD细胞中观察到相反的趋势。同时MrgD过表达降低了HepG2细胞经脂肪酸诱导后脂肪合成及ERS的相关基因蛋白水平。对应的低表达MrgD细胞中上述蛋白表达水平则较对照组明显上调。结论本研究在体外初步揭示了MrgD通过调控内质网应激抑制肝癌细胞脂肪合成,结果提示MrgD途径可能参与肝细胞癌的发展。

Objective Inhibiting the synthesis of fatty acids and cholesterol could effectively reduce the occurrence of liver cancer,which is detrimental to the growth of hepatocarcinoma lesions.This study aims to explore the effect and mechanism of MrgD on the fat metabolism of hepatocyte.Methods The recombinant MrgD overexpression and interference plasmids were packaged by lentivirus to generate stable HepG2 cell lines with MrgD high and low expressions,respectively.In vitro steatosis model induced by free fatty acids,the effect of MrgD on HepG2 cells fatty acid metabolism was evaluated by oil red O staining,and fat synthesis-related genes(SREBP2,ACC1)and endoplasmic reticulum stress(ERS)marker protein(BiP)levels.Results The stable HepG2 cells with high or low expression of MrgD were successfully constructed.In the FFA-induced HepG2 cells,high MrgD expression significantly decreased the lipid droplet deposition and TG production compared with MrgD low expression.Meanwhile,MrgD overexpression inhibited the fat synthesis and ERS-related protein levels induced by fatty acids in HepG2 cells.Correspondingly,the expression levels of the fat synthesis and ERS-related proteins were significantly up-regulated in low-expressing MrgD HepG2 cells.Conclusion The study revealed that MrgD inhibits fat synthesis in hepatocarcinoma cells by regulating endoplasmic reticulum stress in vitro,suggesting that the MrgD pathway may be involved in developing hepatocellular carcinoma.