Huang Hsiu-Chen, Tao Mi-Hua, Hung Tzu-Min, Chen Jui-Chieh, Lin Zi-Jun, Huang Cheng
Department of Applied Science, National Hsinchu University of Education, Hsinchu, Taiwan.
Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan.
Antiviral Res. 2014 Nov;111:100-11. doi: 10.1016/j.antiviral.2014.09.009. Epub 2014 Sep 27.
Hepatitis B virus (HBV) is a major cause of liver disease and hepatocellular carcinoma. Chronic HBV infection is currently managed with either nucleoside/nucleotide-based or interferon-based therapies, but fails to clear infection in a substantial proportion of cases, and antiviral strategies targeting the early stages of infection are therefore required for the prevention of HBV infection. In this study, we examined some common phytochemicals and identified epigallocatechin-3-gallate (EGCG) as a new inhibitor of HBV entry. EGCG, a flavonoid present in green tea extract, belongs to the subclass of catechins. We demonstrated that EGCG at a concentration of 50μM inhibited HBV entry into immortalized human primary hepatocytes by more than 80%, whereas the other four catechins tested had much weaker inhibitory effects. DMSO-differentiated HuS-E/2 cells expressed sodium taurocholate cotransporting polypeptide (NTCP), which is a receptor for HBV. Application of EGCG during HBV inoculation markedly inhibited infection in both DMSO-differentiated HuS-E/2 cells and HA-NTCP-expressing Huh7 cells. Interestingly, EGCG induced clathrin-dependent endocytosis of NTCP from the plasma membrane followed by protein degradation. In addition, EGCG inhibited the clathrin-mediated endocytosis of transferrin. Treatment of cells with EGCG had no effect on HBV genome replication or virion secretion. Moreover, the characteristic of HBV virion and the expression of known HBV entry factors were unaltered by EGCG. Finally, the antiviral activity of EGCG on HBV entry was observed using four different genotypes, A to D. These results show that the green tea-derived molecule EGCG potently inhibits HBV entry and could be used in prevention of HBV reinfection.
乙型肝炎病毒（HBV）是肝脏疾病和肝细胞癌的主要病因。目前，慢性HBV感染采用核苷/核苷酸类或干扰素类疗法进行治疗，但在相当一部分病例中无法清除感染，因此需要针对感染早期阶段的抗病毒策略来预防HBV感染。在本研究中，我们检测了一些常见的植物化学物质，并确定表没食子儿茶素-3-没食子酸酯（EGCG）是一种新的HBV进入抑制剂。EGCG是绿茶提取物中的一种黄酮类化合物，属于儿茶素亚类。我们证明，浓度为50μM的EGCG可抑制HBV进入永生化人原代肝细胞，抑制率超过80%，而所检测的其他四种儿茶素的抑制作用则弱得多。二甲基亚砜（DMSO）分化的HuS-E/2细胞表达牛磺胆酸钠共转运多肽（NTCP），它是HBV的受体。在接种HBV期间应用EGCG可显著抑制DMSO分化的HuS-E/2细胞和表达HA-NTCP的Huh7细胞中的感染。有趣的是，EGCG诱导NTCP从质膜发生网格蛋白依赖性内吞作用，随后蛋白质降解。此外，EGCG抑制转铁蛋白的网格蛋白介导的内吞作用。用EGCG处理细胞对HBV基因组复制或病毒粒子分泌没有影响。此外，EGCG未改变HBV病毒粒子的特性和已知HBV进入因子的表达。最后，使用四种不同的基因型A至D观察到EGCG对HBV进入的抗病毒活性。这些结果表明，源自绿茶的分子EGCG可有效抑制HBV进入，并可用于预防HBV再感染。
