脂滴自噬在丙型肝炎病毒核心蛋白下调沉默信息调节因子1诱导小鼠肝脂肪变性中的作用

The effect of lipophagy on hepatitis C virus core protein-induced hepatic steatosis viadown-regulation of silent information regulator 1 in mice

目的研究脂滴自噬在HCV核心蛋白下调沉默信息调节因子1(SIRT1)诱导小鼠肝脂肪变性中的作用。方法小鼠随机分为两组,每组10只。实验组小鼠尾静脉注射HCV core重组表达载体。对照组小鼠尾静脉注射磷酸盐缓冲溶液。1个月后处死小鼠。检测肝功能、脂联素、血清和肝内甘油三酰(TG)、肝脏组织病理学检查肝脂肪变性程度。蛋白质免疫法检测肝脏SIRT1蛋白、脂联素受体(AdipoR)蛋白以及脂滴自噬相关蛋白微管相关蛋白1轻链3-Ⅱ(LC3-Ⅱ)、脂肪分化相关蛋白(ADRP)、尾部作用蛋白(TIP-47)和P62蛋白的表达。计量资料采用t检验。结果与对照组相比,HCV组小鼠出现肝脂肪变性;肝脏TG含量明显增加[(80.9±20.1)比(45.8±10.5)μg/mg,t=4.964,P<0.01];血清脂联素[(1.05±0.25)比(1.41±0.45)ng/mL,t=2.211,P<0.05]水平下降;SIRT1蛋白水平(0.4±0.1比0.9±0.2,t=7.071,P<0.01)和AdipoR2蛋白水平(0.4±0.1比0.8±0.2,t=5.656,P<0.01)下降;LC3-Ⅱ蛋白(0.8±0.2比0.4±0.1,t=5.656,P<0.01)、TIP-47蛋白(0.9±0.3比0.4±0.1,t=5.000,P<0.01)和ADRP蛋白(0.8±0.3比0.4±0.1,t=4.000,P<0.01)表达增加;而p62蛋白(0.7±0.2比0.8±0.3,t=0.877,P>0.05)表达水平差异无统计学意义。结论 HCV核心蛋白下调SIRT1表达,下调脂联素及受体表达,引起不完全脂滴自噬导致肝脂肪变性。

Objective To investigate the effect of lipophagy on hepatitis C virus（HCV）core protein-induced hepatic steatosis viadown-regulating silent information regulator 1（SIRT1）in mice.Methods Mice were randomized into HCV group and control group（n=10 in both groups）,with injection of HCV core recombinant expression vectors or sterile phosphate buffered solution（PBS）through the tail vein,respectively.All mice were sacrificed in 1 month after the injection.Liver function and serum adiponectin were collected.Total triacylglycerol（TG）were measured in both serum and liver tissues.Levels of SIRT1 protein,adiponectin receptor 2（AdipoR2）protein,light chain 3-Ⅱ（LC3-Ⅱ）protein,adipose differentiation related protein（ADRP）,tail interacting protein 47 KD（TIP-47）and P62 protein in liver were measured using western blot.Quantitative data was analyzed using t-test.Results In HCV group,histopathological examinations revealed hepatic steatosis,and the hepatic TG content（80.9±20.1 vs 45.8±10.5μg/mg,t=4.964,P〈0.01）and levels of LC3-Ⅱ protein（0.8±0.2 vs 0.4±0.1,t=5.656,P〈0.01）,TIP-47 protein（0.9±0.3 vs 0.4±0.1,t=5.000,P〈0.01）and ADRP protein（0.8±0.3 vs 0.4±0.1,t=4.000,P〈0.01）were all increased than those in the control group.However,serum adiponectin（1.05±0.25 vs 1.41±0.45 ng/ml,t=2.211,P〈0.05）,SIRT1 protein（0.4±0.1 vs 0.9±0.2,t=7.071,P〈0.01）and AdipoR2 protein（0.4±0.1 vs 0.8±0.2,t=5.656,P〈0.01）were decreased in HCV mice group compared with those in control group.Expression of P62 protein（0.7±0.2 vs 0.8±0.3,t=0.877,P〈0.05）showed no significant difference between the two groups.Conclusion HCV core protein might cause hepatic steatosis viainducing incomplete lipophagy through down-regulating the expression of SIRT1,adiponectin and AdipoR2.