Chen Yunzhi, Yan Xuemei, Xu Xiao, Yuan Shuhua, Xu Fen, Liang Hua
Department of Endocrinology and Metabolism, Third Affiliated Hospital of Sun Yat-Sen University, and Guangdong Provincial Key Laboratory of Diabetology, Guangzhou, China.
Department of Endocrinology and Metabolism, No. 903 Hospital of PLA Joint Logistic Support Force, Hangzhou, China.
Endocrine. 2020 Dec;70(3):517-525. doi: 10.1007/s12020-020-02470-7. Epub 2020 Aug 30.
GLP-1 receptor agonists, such as exenatide, have been proven to attenuate nonalcoholic fatty liver disease (NAFLD) in vivo and in vitro. However, the efficiency of exenatide had interindividual differences. PNPLA3 is a major susceptibility gene for NAFLD and its I148M polymorphism increases the risk of all disorders of the NAFLD spectrum. Whether this variant contributes to variability in exenatide response is still unclear.
PNPLA3 148I knockin HepG2 cells were constructed using the Cas9/sgRNA system. Oil Red O staining combined with TG quantification was used to evaluate lipid accumulation. Western blotting and qRT-qPCR were conducted, respectively, to measure the protein and mRNA expression of lipid metabolic and endoplasmic reticulum (ER) stress-related inflammatory markers. PNPLA3 I148M was genotyped in type 2 diabetics using Sanger sequencing. The exenatide-induced changes in liver fat content and other clinical parameters were compared between PNPLA3 I148M genotypes.
Lipid deposition increased in both PNPLA3 148I/I and 148M/M HepG2 cells treated with palmitoleic acid, while cells with 148M/M had a higher TG content than those with 148I/I. Exendin-4 treatment was showed to be more significant in 148I/I cells than in 148M/M cells in terms of reducing the intrahepatic fat content, inhibiting SREBP-1c and ER stress-related inflammation, and activating AMPK-ACC lipid oxidation pathway. In patients with type 2 diabetes, 24-week treatment with exenatide improved liver fat content in patients carrying PNPLA3 148I/I better than in patients with 148M/M.
PNPLA3 I148M might modify the anti-NAFLD response to exenatide.
胰高血糖素样肽-1（GLP-1）受体激动剂，如艾塞那肽，已被证实在体内和体外均可减轻非酒精性脂肪性肝病（NAFLD）。然而，艾塞那肽的疗效存在个体差异。PNPLA3是NAFLD的一个主要易感基因，其I148M多态性增加了NAFLD谱中所有疾病的风险。该变体是否导致艾塞那肽反应的变异性仍不清楚。
使用Cas9/sgRNA系统构建PNPLA3 148I敲入HepG2细胞。采用油红O染色结合甘油三酯（TG）定量来评估脂质蓄积。分别进行蛋白质印迹法和qRT-qPCR，以检测脂质代谢和内质网（ER）应激相关炎症标志物的蛋白质和mRNA表达。使用桑格测序法对2型糖尿病患者的PNPLA3 I148M进行基因分型。比较PNPLA3 I148M基因型之间艾塞那肽诱导的肝脏脂肪含量变化和其他临床参数。
在用棕榈油酸处理的PNPLA3 148I/I和148M/M HepG2细胞中，脂质沉积均增加，而148M/M细胞的TG含量高于148I/I细胞。在降低肝内脂肪含量、抑制固醇调节元件结合蛋白-1c（SREBP-1c）和ER应激相关炎症以及激活腺苷酸活化蛋白激酶-乙酰辅酶A羧化酶（AMPK-ACC）脂质氧化途径方面，艾塞那肽-4治疗在148I/I细胞中比在148M/M细胞中更显著。在2型糖尿病患者中，24周的艾塞那肽治疗改善携带PNPLA3 148I/I患者的肝脏脂肪含量比148M/M患者更好。
PNPLA3 I148M可能会改变对艾塞那肽的抗NAFLD反应。
