Role of core protein mutations in the development of occult HBV infection
Role of core protein mutations in the development of occult HBV infection
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核心蛋白突变在隐匿性乙型肝炎病毒感染发展中的作用
DOI：
10.1016/j.jhep.2020.12.023
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发表时间：
2021-05-14
影响因子：
25.7
通讯作者：
Li, Tingting
中科院分区：
文献类型：
--
作者：
Chen, Jingna;Liu, Bochao;Li, Tingting
背景与目的：隐匿性HBV感染（OBI）与输血传播的HBV感染和肝细胞癌有关。关于OBI发生的研究主要集中在S区和调控元件的突变上。方法：从26株B基因型OBI样本中，通过序列比对和Western blot分析，筛选出一株核心蛋白/衣壳（Cp）发生9个氨基酸（aa）替换的OBI株（SZA），以探讨Cp突变对病毒抗原产生的影响。通过在HBV基因组的1.3倍长度上携带SZA或野生型（WT）Cp的复制能力pHBV1.3产生了一个由30个Cp复制子组成的大组，其中各种Cp突变体通过修复SZA-Cp的位点突变或通过定点诱变产生WT-Cp的位点突变而单独引入。分别对转染Huh 7细胞或感染小鼠中单个SZA和WT Cp突变复制子的HBcAg、HBeAg、HBsAg和病毒RNA的表达进行定量。Cp突变体对细胞内或细胞外病毒蛋白产生的影响的分析表明，Cp中的W 62 R突变对HBV复制期间HBcAg和HBeAg产生的减少具有关键影响，而P50 H和/或S74 G突变在体内影响病毒蛋白产生方面发挥有限作用。HBV Cp中的W 62 R及其组合突变可能会在病毒复制期间大量影响HBcAg和HBeAg的产生，这反过来可能有助于OBI的发生。隐匿性B型肝炎病毒感染（OBI）已被发现与HBV S区的氨基酸突变有关，但核心蛋白（Cp）突变的作用仍不清楚。在这项研究中，OBI菌株（SZA）携带9个氨基酸取代的Cp已全面检查在体外和体内。Cp中的W 62 R突变主要减少HBV复制期间的HBcAg和HBeAg产生，可能导致OBI的发生。(C)2021年欧洲肝脏研究协会。Elsevier B. V.出版，保留所有权利。
Background & Aims: Occult HBV infection (OBI) is associated with transfusion-transmitted HBV infection and hepatocellular carcinoma. Studies on OBI genesis have concentrated onmutations in the S region and the regulatory elements. Herein, we aimed to determine the role of mutations in the core region on OBIs.Methods: An OBI strain (SZA) carrying 9 amino acid (aa) substitutions in the core protein/capsid (Cp) was selected by sequence alignment and Western blot analysis from 26 genotype B OBI samples to extensively explore the impact of Cp mutations on viral antigen production in vitro and in vivo.Results: A large panel of 30 Cp replicons were generated by a replication-competent pHBV1.3 carrying SZA or wild-type (WT) Cp in a 1.3-fold over-length of HBV genome, in which the various Cp mutants were individually introduced by repairing site mutations of SZA-Cp or creating site mutations of WT-Cp by site-directed mutagenesis. The expression of HBcAg, HBeAg, and HBsAg and viral RNA was quantified from individual SZA and WT Cp mutant replicons in transfected Huh7 cells or infected mice, respectively. An analysis of the effect of Cp mutants on intracellular or extracellular viral protein production indicated that the W62R mutation in Cp had a critical impact on the reduction of HBcAg and HBeAg production during HBV replication, whereas P50H and/or S74G mutations played a limited role in influencing viral protein production in vivo.Conclusions: W62R and its combination mutations in HBV Cp might massively affect HBcAg and HBeAg production during viral replication, which, in turn, might contribute to the occurrence of OBI.Lay summary: Occult hepatitis B virus infections (OBIs) have been found to be associated with amino acid mutations in the S region of the HBV, but the role of mutations in the core protein (Cp) remains unclear. In this study, an OBI strain (SZA) carrying 9 amino acid substitutions in Cp has been examined comprehensively in vitro and in vivo. The W62R mutation in Cp majorly reduces HBcAg and HBeAg production during HBV replication, potentially contributing to the occurrence of OBI. (C) 2021 European Association for the Study of the Liver. Published by Elsevier B.V. All rights reserved.