关键词：CRISPR/Cas9； HBx; HDAC抑制剂；乙型肝炎病毒 (HBV);可访问性；共价闭合环状 DNA (cccDNA)；表观遗传调控；干扰素（干扰素）；稳定。
本文受版权保护。版权所有。 作者: StephenW 时间: 2021-11-17 12:48
Hepatitis B Virus cccDNA Minichromosomes in Distinct Epigenetic Transcriptional States Differ in Their Vulnerability to Damage
Yang Wang 1 , Yumeng Li 1 , Wenjing Zai 1 , Kongying Hu 1 , Yuanfei Zhu 1 , Qiang Deng 1 2 , Min Wu 3 , Yaming Li 1 , Jieliang Chen 1 2 , Zhenghong Yuan 1 2
Affiliations
Affiliations
1
Key Laboratory of Medical Molecular Virology (MOE/NHC/CAMS), School of Basic Medical Sciences, Shanghai Medical College, Fudan University, Shanghai, China.
2
Research Unit of Cure of Chronic Hepatitis B Virus Infection, Chinese Academy of Medical Sciences, China.
3
Shanghai Public Health Clinical Center, Fudan University, Shanghai, China.
PMID: 34779008 DOI: 10.1002/hep.32245
Abstract
Background and aims: Hepatitis B virus (HBV) covalently closed circular DNA (cccDNA) is a major obstacle for a cure of chronic hepatitis B. Accumulating evidence suggests that epigenetic modifications regulate the transcriptional activity of cccDNA minichromosomes. However, it remains unclear how the epigenetic state of cccDNA affects its stability.
Approaches and results: By using HBV infection cell models, in vitro and in vivo recombinant cccDNA (rcccDNA) and the HBVcircle models, the reduction rate of HBV cccDNA and the efficacy of APOBEC3A- and CRISPR/Cas9-mediated cccDNA targeting were compared between cccDNAs with distinct transcriptional activities. Interferon-α treatment and HBx deletion were applied as two strategies for cccDNA repression. Chromatin immunoprecipitation and micrococcal nuclease assays were performed to determine the epigenetic pattern of cccDNA. The HBV cccDNA levels remained stable in non-dividing hepatocytes, however, they were significantly reduced during cell division, and the reduction rate was similar between cccDNAs in transcriptionally-active and transcriptionally-repressed states. Strikingly, HBV rcccDNA without HBx expression exhibited a significantly longer persistence in mice. The cccDNA in low transcriptional activity exhibited an epigenetic inactive pattern and was more difficult to access by APOBEC3A and engineered CRISPR-Cas9. The epigenetic regulator activating cccDNA increased its vulnerability to APOBEC3A.
Conclusions: HBV cccDNA minichromosomes in distinct epigenetic transcriptional states showed a similar reduction rate during cell division, but significantly differ in their accessibility and vulnerability to targeted nucleases and antiviral agents. Epigenetic sensitization of cccDNA makes it more susceptible to damage and may potentially contribute to an HBV cure.
Keywords: CRISPR/Cas9; HBx; HDAC inhibitor; Hepatitis B virus (HBV); accessibility; covalently closed circular DNA (cccDNA); epigenetic Regulation; interferon (IFN); stability.
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