Related Experiment Video
Updated: Mar 29, 2026
Analysis of HBV-Specific CD4 T-cell Responses and Identification of HLA-DR-Restricted CD4 T-Cell Epitopes Based on a Peptide Matrix
Published on: October 20, 2021
An HBV-Derived Peptide Poly6 as a Novel Candidate for Functional Cure Via IFN-I-Mediated Epigenetic Regulation of
Junghwa Jang1, Dong Hyun Kim1, Ziyun Kim1
1Department of Microbiology and Immunology, College of Medicine, Seoul National University, Seoul, Republic of Korea.
Insights
Poly6, a peptide from hepatitis B virus (HBV), effectively reduces HBV DNA and RNA by activating interferon pathways. This peptide shows promise for a functional cure in chronic HBV infection.
Area of Science:
- Virology
- Immunology
- Molecular Biology
Background:
- Chronic hepatitis B virus (HBV) infection is difficult to cure, primarily due to covalently closed circular DNA (cccDNA).
- Novel therapeutic strategies targeting cccDNA are crucial for achieving a functional cure.
Purpose of the Study:
- To investigate the antiviral efficacy and mechanism of Poly6, an HBV-encoded peptide, against chronic HBV infection.
- To evaluate Poly6's potential as a therapeutic candidate for HBV control.
Main Methods:
- In vitro studies using hepatocyte-derived cell lines.
- In vivo studies in hydrodynamic injection models and HBV transgenic mice.
- Mechanistic analyses involving mitochondrial stress, STING-IRF3 pathway, IFI16 induction, and epigenetic modifications of cccDNA.
Main Results:
- Poly6 significantly reduced cccDNA, pregenomic RNA, and viral DNA with no observed cytotoxicity.
- Poly6 demonstrated synergistic antiviral effects when combined with entecavir.
- Poly6 induced a type I interferon (IFN-I) response via mitochondrial stress and IFI16 activation, leading to epigenetic silencing of cccDNA.
Conclusions:
- Poly6 triggers a unified IFN-I-centered cascade that targets multiple stages of the HBV lifecycle.
- Poly6 exhibits significant therapeutic potential for achieving durable control of chronic HBV infection.
Abstract:
Covalently closed circular DNA (cccDNA) represents the central obstacle to achieving a functional cure for chronic hepatitis B virus (HBV) infection. Poly6, a peptide encoded within the HBV genome, was investigated for antiviral efficacy in hepatocyte-derived cell lines, hydrodynamic injection models, and HBV transgenic mice. Poly6 administration markedly decreased cccDNA, pregenomic RNA, and viral DNA without detectable cytotoxicity. Poly6 also showed synergistic antiviral effects with entecavir. Mechanistic analyzes demonstrated that Poly6 initiates parallel upstream events: mitochondrial stress resulting in oxidized mtDNA release and activation of the STING-IRF3 pathway, and induction of IFI16, a nuclear DNA sensor implicated in interferon regulation. Both signals converged on robust type I interferon (IFN-I) production. The IFN-I response subsequently promoted expression of canonical ISGs, including iNOS, which generated nitric oxide to disrupt nucleocapsid assembly. Concurrently, IFI16, whose abundance was further increased by interferon signaling, amplified IFN-I production and imposed epigenetic silencing of cccDNA through Sp1 sequestration and histone hypoacetylation. Chromatin immunoprecipitation confirmed reduced acetylation of H3K27, H4K5, and H4K12 on cccDNA minichromosomes. These results delineate a unified IFN-I-centered cascade in which Poly6 coordinates complementary antiviral activities, supporting its translational potential as a therapeutic candidate for durable HBV control.
Related Concept Videos
01:30Inhibitors of Viral Protein Synthesis
01:29Immune Response Against Viral Pathogens
NK Cells
NK cells are a crucial part of our innate immune system, acting as the first line of defense against viral infections. These cells can recognize and kill infected cells without prior exposure to the virus, effectively slowing down the spread of infection. Additionally, NK cells produce proinflammatory...