乙型肝炎病毒X基因突变体在抗病毒治疗期间出现，并增加cccD

StephenW

Hepatitis B virus X gene mutants emerge during antiviral therapy and increase cccDNA levels to compensate for replication suppression
Chih-Lang Lin  1   2   3   4 , Rong-Nan Chien  1   2   3   4 , Yu-De Chu  2 , Kung-Hao Liang  5 , Ya-Hui Huang  2   3 , Po-Yuan Ke  6 , Kwang-Huei Lin  6 , Yang-Hsiang Lin  7   8 , Chau-Ting Yeh  9   10   11   12
Affiliations

    PMID: 32770306 DOI: 10.1007/s12072-020-10079-1

Abstract

Background: Hepatitis B virus (HBV) X gene (HBx) mutants can develop during the natural course of chronic HBV infection. However, little is known about whether the emergence of HBx mutants during long-term antiviral therapy is an adaptation of HBV to antiviral stress. This study was to identify HBx mutants that emerged in patients experiencing Lamivudine resistance or suboptimal treatment.

Methods: Forty-six Lamivudine-resistant patients and 46 patients with suboptimal treatment responses to Entecavir were enrolled in this study. HBx mutants were identified by sequence analysis and their roles in the HBV replication cycle were characterized.

Results: We show that deletion/truncation/insertion mutations were only detected in the Lamivudine resistance group, while synonymous mutations were found in both groups. Follow-up analyses revealed that five patients in the Lamivudine group developed hepatocellular carcinoma, while patients in the Entecavir group did not. These mutants were characterized by a significant decrease in transactivation of the pre-S1 promoter, and varying effects on transactivation of the X promoter. Co-transfection of HBx-mutant plasmid and HBV replication-competent clone into HepG2 cells resulted in increased nuclear-to-cytoplamic HBV core antigen, HBV-DNA ratios, and nuclear covalently closed circular DNA (cccDNA). Antiviral drug sensitivity assays revealed that these mutants exhibited a compensatory effect to counteract antiviral drug suppression, resulting in elevated secretory HBV-DNA levels.

Conclusions: Our study demonstrates that HBx mutants can emerge during Lamivudine or Entecavir therapy. These mutants exhibit altered transactivation of the HBV pre-S1 and X promoters, leading to increased cccDNA levels to compensate for replication suppression.

Keywords: Entecavir; Lamivudine; Pre-S1 promoter; Suboptimal response; Transactivation.

StephenW

乙型肝炎病毒X基因突变体在抗病毒治疗期间出现，并增加cccDNA水平以补偿复制抑制
林志朗1 2 3 4，钱荣南1 2 3 4，朱玉德2，梁公好5，黄雅慧2 3，坡媛媛6，林光辉6，杨-祥林7 8，叶秋婷9 10 11 12
隶属关系

    PMID：32770306 DOI：10.1007 / s12072-020-10079-1

抽象

背景：乙型肝炎病毒（HBV）X基因（HBx）突变体可以在慢性HBV感染的自然过程中发展。但是，关于长期抗病毒治疗期间HBx突变体的出现是否是HBV对抗病毒应激的适应性知之甚少。这项研究旨在确定出现拉米夫定耐药或治疗效果欠佳的患者中出现的HBx突变体。

方法：本研究纳入了46例对拉米夫定耐药的患者和46例对恩替卡韦治疗效果欠佳的患者。通过序列分析鉴定了HBx突变体，并表征了它们在HBV复制周期中的作用。

结果：我们显示仅在拉米夫定耐药组中检测到缺失/截短/插入突变，而在两组中均发现了同义突变。后续分析显示，拉米夫定组中有5例患上肝细胞癌，而恩替卡韦组中则没有。这些突变体的特征在于前S1启动子的反式激活显着减少，并且对X启动子的反式激活具有不同的影响。将HBx突变质粒和具有HBV复制能力的克隆共转染到HepG2细胞中，导致核细胞间质HBV核心抗原，HBV-DNA比率和核共价闭合环状DNA（cccDNA）的增加。抗病毒药物敏感性测定表明，这些突变体显示出抵消抗病毒药物抑制作用的补偿作用，导致分泌型HBV-DNA水平升高。

结论：我们的研究表明，拉米夫定或恩替卡韦治疗期间可出现HBx突变体。这些突变体表现出改变的HBV pre-S1和X启动子反式激活，从而导致cccDNA水平增加，以补偿复制抑制。

关键字：恩替卡韦；拉米夫定; S1前启动子；次优反应；反激活。