ERK1/2-核因子-кB通路介导乙型肝炎病毒x蛋白抑制过氧化物酶体增殖物激活受体-α表达

ERK1/2-NF-κB inhibited the expression of peroxisome proliferator activated receptorαafter the transfection of HBx plasmid

目的研究乙型肝炎病毒X蛋白(HBx)对过氧化物酶体增殖物激活受体(PPAR)-α的抑制作用,并探讨其中的内在机制。方法培养人肝癌细胞系HepG2,转染HBx表达质粒,Western blot方法检测PPAR-α、丝裂原活化蛋白激酶(MAPK,ERK1／2)和IкB蛋白的变化,凝胶迁移率实验检测核转录因子(NF)-кB蛋白的活性改变,分别加入MAPK和NF-кB特异性的抑制剂PD98059与吡咯烷二硫代氨基甲酸盐(PDTC),观察PPAR-α蛋白的变化。结果(1)HBx质粒转染HepG2后,与对照组相比,ERK2表达增加,NF-кB被激活,PPAR-α的表达下调；(2)阻断NF-кB后,NF-кB的活性下降,PPAR-α的表达增加；(3)阻断MAPK后,转染HBx表达质粒,NF-кB的活性下降,PPAR-α的表达增加。结论HBx抑制细胞核转录因子PPAR-α的表达,可能与ERK1／2-NF-кB激活有关。

Objective To study the inhibitort effects of hepatitis x protein （HBx） on peroxisome proliferator activated reeeptora （PPARα） and its mechanism. Methods HBx expression plasmid was transfeeted into the hepatic cancer cells （ HepG2）, and the HBx expression was detected by using immunofluoreseenee 36 h after transfeetion. EMSA was performed to investigate the affinity of NF-κB, the mRNA and protein expression of PPARα was detected by RT-PCR and Western-blot, and the protein expression levels of ERK2 and IκB were detected by Western blot. When MAPK and NF-κB blocker （PD98059 and PDTC） was added to different groups, the expression level of PPARα protein was detected by Western blot. Results Comparing with control group, the mRNA and protein expression of PPARα was decreased significantly after HBx transfection. After PD98059 or PDTC was added, the expression level of PPARα protein was increased inversely. Conclusion HBx can decrease the expression of PPARα, which may be related with the activation of ERK1/2-NF-κB.