Nosaka Takuto, Naito Tatsushi, Murata Yosuke, Matsuda Hidetaka, Ohtani Masahiro, Hiramatsu Katsushi, Nishizawa Tsutomu, Okamoto Hiroaki, Nakamoto Yasunari
Second Department of Internal Medicine, Faculty of Medical Sciences, University of Fukui, Fukui, Japan.
Division of Virology, Department of Infection and Immunity, Jichi Medical University School of Medicine, Tochigi, Japan.
Hepatol Res. 2022 Feb;52(2):141-152. doi: 10.1111/hepr.13722. Epub 2021 Nov 15.
Curing hepatitis B virus (HBV) infection requires elimination of covalently closed circular DNA (cccDNA). Interferon (IFN)-γ has noncytolytic antiviral potential; however, elimination of cccDNA could not be achieved. To enhance the regulatory effect, we comprehensively analyzed the host factors associated with cccDNA amplification and IFN-γ and IFN-α effects using an in vitro HBV infection system showing various transcription levels.
Primary human hepatocytes were infected with HBV using genomic plasmids carrying the basic core promoter mutation A1762T/G1764A and/or the precore mutation G1896A and treated with IFN-γ and IFN-α. Comprehensive and functional studies involving microarray and small interfering RNA analysis revealed the host factors related to cccDNA regulation.
The HBV infection system reproduced the HBV life cycle and showed various propagation levels. Microarray analysis revealed 53 genes correlated with the cccDNA levels. Of the 53 genes, expression of IFN-induced protein 44-like (IFI44L) was significantly upregulated by IFN-γ and IFN-α. The anti-HBV effect of IFI44L is exerted regardless of IFN-γ or IFN-α by inhibiting the activation of nuclear factor-κB and signal transducer and activator of transcription 1 pathways.
Using the in vitro HBV infection system, an IFN-inducible molecule, IFI44L, associated with cccDNA amplification, was identified. These results suggest an innovative molecular strategy for the regulation of HBV cccDNA by controlling a novel host factor, IFI44L.
治愈乙型肝炎病毒（HBV）感染需要消除共价闭合环状DNA（cccDNA）。干扰素（IFN）-γ具有非细胞溶解性抗病毒潜力；然而，无法实现cccDNA的消除。为增强调节作用，我们使用显示不同转录水平的体外HBV感染系统，全面分析了与cccDNA扩增以及IFN-γ和IFN-α作用相关的宿主因子。
用携带基本核心启动子突变A1762T/G1764A和/或前核心突变G1896A的基因组质粒感染原代人肝细胞，并分别用IFN-γ和IFN-α处理。涉及微阵列和小干扰RNA分析的全面功能研究揭示了与cccDNA调节相关的宿主因子。
HBV感染系统重现了HBV生命周期，并显示出不同的增殖水平。微阵列分析揭示了53个与cccDNA水平相关的基因。在这53个基因中，IFN诱导蛋白44样蛋白（IFI44L）的表达被IFN-γ和IFN-α显著上调。IFI44L通过抑制核因子-κB和信号转导及转录激活因子1途径的激活发挥抗HBV作用，且与IFN-γ或IFN-α无关。
利用体外HBV感染系统，鉴定出一种与cccDNA扩增相关的IFN诱导分子IFI44L。这些结果提示了一种通过控制新型宿主因子IFI44L来调节HBV cccDNA的创新分子策略。
