A nucleosome switch primes Hepatitis B Virus infection [RNA-Seq]
Ontology highlight
ABSTRACT:
ORGANISM(S): Homo sapiens
PROVIDER: GSE225714 | GEO | 2023/03/03
REPOSITORIES: GEO
Similar Datasets
Project description:Chronic hepatitis B virus (HBV) infection is an incurable global health threat capable of causing liver disease and hepatocellular carcinoma. During the genesis of infection, HBV establishes an independent chromosome, cccDNA, consisting of the circular viral genome and host histones. The first viral protein expressed, HBx, induces degradation of a host silencing factor to facilitate infection. However, the relationship between cccDNA’s chromatin and early HBx transcription state remains poorly understood. Using reconstituted viral chromosomes, we found that nucleosomes in cccDNA drive HBx transcription. We corroborated these findings in cells and further showed that chromatin destabilizing drugs inhibit viral transcription and antigen expression in hepatocytes. Our results shed new light on a long-standing paradox and represent a novel therapeutic avenue for the treatment of chronic HBV.
2023-03-03 | GSE225715 | GEO
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.
2022-12-01 | GSE156690 | GEO
Project description:In hepatocyte nuclei, hepatitis B virus (HBV) genomes occur episomally as covalently closed circular DNA (cccDNA). The HBV X protein (HBx) is required to initiate and maintain HBV replication and acts as host gene trans-regulator. However, functionally relevant spatiotemporal localization and interactions of cccDNA and HBx remain to be understood. This is the first study utilizing circularized chromosome conformation capture (4C) to identify regional virus-host genome interactions. We combined 4C with RNA-seq and ChIP-seq to illuminate the nuclear landscape associated with HBV episomes and HBx. Moreover, we functionally studied HBx-binding to episomal HBV DNA. In human HBV-positive HepaRG hepatocytes, 4C and ChIP revealed specific nuclear localization of HBV episomes and HBx associated with actively transcribed nuclear domains correlating well in size with constrained topological units built up by chromatin fibre loops, which are believed to constitute fundamental cell nuclear architectural units. Interestingly, HBx alone occupied transcribed chromatin domains, and its binding to HBV episomes depended on its C-terminus in vitro. In conclusion, HBx and HBV DNA similarly follow higher-order nuclear assembly patterns, specifically favoring transcriptionally active nuclear compartments. These novel observations may shed light on important unsolved problems: to understand the long-term episomal stability and the facilitation of viral persistence.
2018-04-30 | GSE100400 | GEO
Project description:Chronic hepatitis B virus (HBV) infection affects 240 million people worldwide and is a major risk factor for liver failure and hepatocellular carcinoma. Current antiviral therapy inhibits cytoplasmic HBV genomic replication, but is not curative since it does not eliminate nuclear HBV cccDNA, the genomic form that templates viral transcription and sustains viral persistence. Novel approaches that directly target the transcriptional regulation of cccDNA would therefore be highly desirable. cccDNA is assembled with cellular histone proteins into chromatin, but little is known about the regulation of HBV chromatin by histone posttranslational modifications (PTMs). Here, using a new cccDNA ChIP-Seq approach, we report the first genome-wide maps of PTMs in cccDNA-containing chromatin from de novo infected HepG2 cells, primary human hepatocytes and from HBV infected liver tissue. We find high levels of PTMs associated with active transcription enriched at specific sites within the HBV genome, and surprisingly very low levels of PTMs linked to transcriptional repression even at silent HBV promoters. We show that transcription and active PTMs in HBV chromatin are reduced by the activation of an innate immunity pathway, and that this can be recapitulated with a small molecule epigenetic modifying agent, opening the possibility that chromatin-based regulation of cccDNA transcription could be a new therapeutic approach to chronic HBV infection.
2015-10-08 | GSE68402 | GEO
Project description:Hepatitis B virus (HBV) infects 240 million people worldwide. The infection requires establishment and persistence of a viral episome, the covalently closed circular (ccc) DNA, in the nucleus. Here we studied cccDNA spatial localization in the 3D host genome by using chromosome conformation capture based sequencing analysis and fluorescence in situ hybridization (FISH). We show cccDNA is not randomly distributed in host nucleus, rather, it is preferentially accumulated at specialized areas, particularly in regions close to chromosome 19 (chr.19). Activation of cccDNA appears to be associated with its re-localization from a heterochromatin hub pre-established by 5 regions of chr.19 to transcriptionally active regions formed by chromosomes in close proximity to chr.19 including chr. 16, 17, 20, 22. This active versus inactive positioning at discrete regions of host genome is primarily controlled by viral HBx protein and host factors including the structural maintenance of chromosomes protein 5/6 (SMC5/6) complex.
2021-07-06 | GSE145150 | GEO
Project description:Covalently closed circular DNA (cccDNA) forms the basis for replication and persistence of hepatitis B virus (HBV) in the chronically infected liver. We have previously shown through the analysis of de novo HBV infected cell lines that viral transcription is subject to regulation by posttranslational modifications (PTMs) of histone proteins bound to cccDNA. We now report the successful adaptation of this ChIPseq approach for the analysis of fine-needle patient liver biopsy specimens to investigate the role of histone PTMs in chronically HBV-infected patients. Using 18 specimens from patients in different stages of chronic HBV infection our work shows that the profile of histone PTMs in chronic infection is more nuanced than observed in our previous work largely focused on acute infection in in vitro models. Specifically, we find that the majority of recovered HBV sequences are associated with the activating histone PTM H3K4me3, in line with our previous findings. We further find that the striking interpatient variability of its deposition in this patient cohort is linked to viral transcription and patient HBeAg status. Unexpectedly, we detect a significant localized deposition of the inhibitory histone PTM H3K9me3 on HBV-DNA in select patient biopsies which was not observed previously. Altogether, our results show that current in vitro models of HBV infection are unable to fully recapitulate the complex epigenetic landscape of chronic HBV infection observed in vivo and demonstrate that fine needle liver biopsy specimens can provide sufficient material to further investigate the interaction of viral and host proteins on HBV-DNA.
2019-02-07 | GSE113879 | GEO
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
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
Project description:Hepatitis B Virus (HBV) remains a major public health problem, and is a major cause liver cancer worldwide. HBV infection in vivo requires the function of the HBx protein, which facilitates expression of viral genes from the episomal genome by an unknown mechanism. Evidence suggests that HBx functions as a targeting subunit for the CRL4 E3 ubiquitin ligase, redirecting the complex to target and degrade an unknown host restriction factor. We used substrate trapping proteomics to search for ubiquitylation substrates of HBx. We used MLN4924 to block CRL activity and stabilize interactions between HBx and its substrates. We then performed APMS to identify bound proteins and potential substrates.
2016-09-29 | PXD004762 | Pride
Project description:Hepatitis B virus (HBV) infection could cause hepatitis, liver cirrhosis and hepatocellular carcinoma. HBV-mediated pathogenesis is only partially understood, but X protein (HBx) reportedly possesses oncogenic potential. Exosomes are small membrane vesicles with diverse functions released by various cells including hepatocytes, and HBV harnesses cellular exosome biogenesis and export machineries for virion morphogenesis and secretion. Therefore, HBV infection might cause changes in exosome contents with functional implications for both virus and host. In this project, exosome protein content changes induced by HBV and HBx were quantitatively analyzed by SILAC/LC-MS/MS. Exosomes prepared from SILAC-labeled hepatoma cell line Huh-7 transfected with HBx, wildtype or HBx-null HBV replicon plasmids were analyzed by LC-MS/MS.
2014-10-09 | PXD001339 | Pride