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A nucleosome switch primes Hepatitis B Virus infection [ChIP-Seq]

ABSTRACT: Chronic hepatitis B virus (HBV) infection is an incurable global health threat responsible for causing liver disease and hepatocellular carcinoma. During the genesis of infection, HBV establishes an independent minichromosome consisting of the viral covalently closed circular DNA (cccDNA) genome and host histones. The viral X gene must be expressed immediately upon infection to induce degradation of the host silencing factor, Smc5/6. However, the relationship between cccDNA chromatinization and X gene transcription remains poorly understood. Establishing a reconstituted viral minichromosome platform, we found that nucleosome occupancy in cccDNA drives X transcription. We corroborated these findings in cells and further showed that the chromatin destabilizing molecule CBL137 inhibits X transcription and HBV infection in hepatocytes. Our results shed light on a long-standing paradox and represent a potential new therapeutic avenue for the treatment of chronic HBV infection.

ORGANISM(S): Homo sapiens

PROVIDER: GSE270130 | GEO | 2024/06/19

REPOSITORIES: GEO

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A nucleosome switch primes Hepatitis B Virus infection [Mnase-Seq, ChIP-Seq]

Project description:Chronic hepatitis B virus (HBV) infection is an incurable global health threat responsible for causing liver disease and hepatocellular carcinoma. During the genesis of infection, HBV establishes an independent minichromosome consisting of the viral covalently closed circular DNA (cccDNA) genome and host histones. The viral X gene must be expressed immediately upon infection to induce degradation of the host silencing factor, Smc5/6. However, the relationship between cccDNA chromatinization and X gene transcription remains poorly understood. Establishing a reconstituted viral minichromosome platform, we found that nucleosome occupancy in cccDNA drives X transcription. We corroborated these findings in cells and further showed that the chromatin destabilizing molecule CBL137 inhibits X transcription and HBV infection in hepatocytes. Our results shed light on a long-standing paradox and represent a potential new therapeutic avenue for the treatment of chronic HBV infection.

2023-03-03 | GSE225715 | GEO

A nucleosome switch primes Hepatitis B Virus infection [RNA-Seq]

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2021-07-06 | GSE145150 | GEO

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Project description:Chronic infection of Hepatitis B virus (HBV) remains a public health problem worldwide. HBV infection relies on the persistence of covalently closed circular DNA (cccDNA) in the nucleus and actively cccDNA transcription. To understand HBV cccDNA transcription regulation at single cell level, we isolated primary human hepatocytes from liver humanized FRG mice infected by one or more (two or three) HBV genotypes, and we quantified transcripts of HBV structural genes in single cells. HBV transcripts were ascribed to the transcription of individual HBV genes by 5’ end sequencing thus avoiding the ambiguity caused by the overlap of viral genome coding at the 3’ ends. Transcripts from different cccDNA in single cells were separated according to the single-nucleotide polymorphism (SNP) among different HBV genotypes. We found that the transcription of HBV follows “all-or-none” pattern in single cells: either all of the individual cccDNA molecules actively transcribe simultaneously, or, none of them generates transcripts of the structural genes. In vitro cell infection assays with recombinant HBV are consistent with the sequencing results of ex vivo samples from natural HBV infection, and also confirm that such a pattern is apparently controlled by the expression of HBx protein. These results strongly support a synchronized transcription model of HBV cccDNA molecules in single hepatocytes, and provide new insight helpful for developing HBV cure strategy.

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Hepatocyte Host Factor IFI44L Regulates the Innate and Acquired Immune Responses to Hepatitis B Virus

Project description:Objective: Curing hepatitis B requires the complete elimination of covalently closed circular DNA (cccDNA). Interferon (IFN)-γ is produced by cytotoxic T lymphocytes and has noncytolytic antiviral potential; however, elimination of cccDNA could not be achieved. To enhance the regulatory effect of IFN-γ, we comprehensively analyzed the host factors that associated with cccDNA amplification and IFN-γ effects using the in vitro HBV infection system that exhibits various transcription levels. Design: Primary human hepatocytes were infected with HBV using genomic plasmids carrying the basic core promoter 1762/1764 and/or the precore 1896 mutation and treated with IFN-γ, IFN-α, and entecavir. Comprehensive expression analysis and functional studies were performed to analyze the host factors related to the cccDNA regulation using RNA microarray and siRNA analysis. Results: HBV infection system accurately reproduced the HBV life cycle and exhibited various transcription levels. Microarray analysis revealed that 53 genes increased depending on the cccDNA levels. Of 53 genes, the expression of IFN-induced protein 44-like (IFI44L) was the most upregulated by IFN-γ and IFN-α but not entecavir, and associated with the anti-viral effects of IFN-γ. siRNA analysis revealed that IFI44L negatively regulates the innate immune response and IFN-γ function to suppress HBV transcription and propagation by inhibiting the activation of NF-κB and STAT1 pathways.

2020-12-12 | GSE163042 | GEO

Hepatitis B virus core protein is not required for cccDNA transcriptional regulation

Project description:Background & Aims: Hepatitis B virus (HBV) infection is a major health burden worldwide and currently there is no cure. The persistence of HBV covalently closed circular DNA (cccDNA) is the major obstacle for antiviral treatment. HBV core protein (HBc) has merged as a promising antiviral target, as it plays important roles in critical steps of viral life cycle. However, whether HBc could regulate HBV cccDNA transcription remains to be illustrated. Methods: Synthesized HBV cccDNA and HBVcircle with or without HBc deficiency were transfected into hepatocytes. A recently reported Adeno-Associated Virus (AAV) mediated HBV cccDNA mouse model was employed. Two capsid assembly modulators (CAMs) were used. HBV replication markers were evaluated. Chromatin immunoprecipitation (ChIP) or ChIP sequencing assays were conducted with different transcription factors, histones and RNA polymerase 2. Results: In HBV cccDNA and HBVcircle transfection assays, lack of HBc showed no effect on transcription of HBV RNA as well as HBV surface antigen production. Reconstitution of HBc did not change cccDNA derived HBV markers. Similar results were obtained in vivo, from mouse cccDNA model. ChIP data revealed similar transcription regulation of HBc deficient cccDNA chromatin with wide type cccDNA. Furthermore, CAMs treatment could not alter cccDNA transcription. Conclusions: Our results indicate that HBc neither affects histone modifications and transcription factors binding of cccDNA, nor influences cccDNA transcription. Although CAMs could reduce HBc binding to cccDNA, it does not suppress cccDNA transcriptional activity. Thus, therapeutic targeting capsid or HBc is not sufficient to reduce cccDNA transcription.

2022-04-01 | GSE199653 | GEO

Characterization of early transcriptomic changes associated with hepatitis B virus exposure in human and macaque immune cell populations

Project description:Chronic hepatitis B virus (HBV) infection affects close to 300 million individuals worldwide, representing one of the major etiological factors for the development of cirrhosis and hepatocellular carcinoma (HCC). At the molecular level, the mechanisms behind chronic HBV infection are based on the persistence of the viral genome as an episomal structure termed covalently closed circular DNA (cccDNA), and the evasion of both innate and adaptive immune responses. Thus, it is considered that HBV cure will be a multi-layered combination approach of anti-viral and immune-boosting strategies. Although the development of potential HBV therapeutics has been hampered by the lack of suitable long-term infection models, the stark contrast between human and non-human primates regarding their immune responses and infection outcomes, represents an opportunity to identify the molecular mechanisms favoring HBV elimination. Therefore, we aimed to characterize the early transcriptomic changes associated with HBV exposure in human and macaque immune cell populations.

2023-08-08 | GSE223073 | GEO

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