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Niller HH, Ay E, Banati F, Demcsák A, Takacs M, Minarovits J. Wild type HBx and truncated HBx: Pleiotropic regulators driving sequential genetic and epigenetic steps of hepatocarcinogenesis and progression of HBV-associated neoplasms. Rev Med Virol 2015; 26:57-73. [PMID: 26593760 DOI: 10.1002/rmv.1864] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2015] [Revised: 09/30/2015] [Accepted: 10/15/2015] [Indexed: 12/23/2022]
Abstract
Hepatitis B virus (HBV) is one of the causative agents of hepatocellular carcinoma. The molecular mechanisms of tumorigenesis are complex. One of the host factors involved is apparently the long-lasting inflammatory reaction which accompanies chronic HBV infection. Although HBV lacks a typical viral oncogene, the HBx gene encoding a pleiotropic regulatory protein emerged as a major player in liver carcinogenesis. Here we review the tumorigenic functions of HBx with an emphasis on wild type and truncated HBx variants, and their role in the transcriptional dysregulation and epigenetic reprogramming of the host cell genome. We suggest that HBx acquired by the HBV genome during evolution acts like a cellular proto-onc gene that is activated by deletion during hepatocarcinogenesis. The resulting viral oncogene (v-onc gene) codes for a truncated HBx protein that facilitates tumor progression. Copyright © 2015 John Wiley & Sons, Ltd.
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Affiliation(s)
- Hans Helmut Niller
- Institute for Medical Microbiology and Hygiene, University of Regensburg, Regensburg, Germany
| | - Eva Ay
- Department of Retrovirology, National Center for Epidemiology, Budapest, Hungary
| | - Ferenc Banati
- RT-Europe Nonprofit Research Center, Mosonmagyarovar, Hungary
| | - Anett Demcsák
- University of Szeged, Faculty of Dentistry, Department of Oral Biology and Experimental Dental Research, Szeged, Hungary
| | - Maria Takacs
- Division of Virology, National Center for Epidemiology, Budapest, Hungary
| | - Janos Minarovits
- University of Szeged, Faculty of Dentistry, Department of Oral Biology and Experimental Dental Research, Szeged, Hungary
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202
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IL6 Inhibits HBV Transcription by Targeting the Epigenetic Control of the Nuclear cccDNA Minichromosome. PLoS One 2015; 10:e0142599. [PMID: 26580974 PMCID: PMC4651563 DOI: 10.1371/journal.pone.0142599] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2015] [Accepted: 10/23/2015] [Indexed: 01/05/2023] Open
Abstract
The HBV covalently closed circular DNA (cccDNA) is organized as a mini-chromosome in the nuclei of infected hepatocytes by histone and non-histone proteins. Transcription from the cccDNA of the RNA replicative intermediate termed pre-genome (pgRNA), is the critical step for genome amplification and ultimately determines the rate of HBV replication. Multiple evidences suggest that cccDNA epigenetic modifications, such as histone modifications and DNA methylation, participate in regulating the transcriptional activity of the HBV cccDNA. Inflammatory cytokines (TNFα, LTβ) and the pleiotropic cytokine interleukin-6 (IL6) inhibit hepatitis B virus (HBV) replication and transcription. Here we show, in HepG2 cells transfected with linear HBV monomers and HBV-infected NTCP-HepG2 cells, that IL6 treatment leads to a reduction of cccDNA-bound histone acetylation paralleled by a rapid decrease in 3.5kb/pgRNA and subgenomic HBV RNAs transcription without affecting cccDNA chromatinization or cccDNA levels. IL6 repressive effect on HBV replication is mediated by a loss of HNF1α and HNF4α binding to the cccDNA and a redistribution of STAT3 binding from the cccDNA to IL6 cellular target genes.
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203
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Rivière L, Gerossier L, Ducroux A, Dion S, Deng Q, Michel ML, Buendia MA, Hantz O, Neuveut C. HBx relieves chromatin-mediated transcriptional repression of hepatitis B viral cccDNA involving SETDB1 histone methyltransferase. J Hepatol 2015; 63:1093-102. [PMID: 26143443 DOI: 10.1016/j.jhep.2015.06.023] [Citation(s) in RCA: 144] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/04/2015] [Revised: 06/16/2015] [Accepted: 06/24/2015] [Indexed: 02/06/2023]
Abstract
BACKGROUND & AIMS Maintenance of the covalently closed circular HBV DNA (cccDNA) that serves as a template for HBV transcription is responsible for the failure of antiviral therapies. While studies in chronic hepatitis patients have shown that high viremia correlates with hyperacetylation of cccDNA-associated histones, the molecular mechanisms controlling cccDNA stability and transcriptional regulation are still poorly understood. This study aimed to decipher the role of chromatin and chromatin modifier proteins on HBV transcription. METHODS We analyzed the chromatin structure of actively transcribed or silenced cccDNA by infecting primary human hepatocytes and differentiated HepaRG cells with wild-type virus or virus deficient (HBVX-) for the expression of hepatitis B virus X protein (HBx), that is required for HBV expression. RESULTS In the absence of HBx, HBV cccDNA was transcriptionally silenced with the concomitant decrease of histone 3 (H3) acetylation and H3K4me3, increase of H3 di- and tri-methylation (H3K9me) and the recruitment of heterochromatin protein 1 factors (HP1) that correlate with condensed chromatin. SETDB1 was found to be the main histone methyltransferase responsible for the deposition of H3K9me3 and HBV repression. Finally, full transcriptional reactivation of HBVX- upon HBx re-expression correlated with an increase of histone acetylation and H3K4me3, and a concomitant decrease of HP1 binding and of H3K9me3 on the cccDNA. CONCLUSION Upon HBV infection, cellular mechanisms involving SETDB1-mediated H3K9me3 and HP1 induce silencing of HBV cccDNA transcription through modulation of chromatin structure. HBx is able to relieve this repression and allow the establishment of active chromatin.
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Affiliation(s)
- Lise Rivière
- Unité des Hépacivirus et Immunité Innée, Institut Pasteur, 28 rue du Dr. Roux, 75015 Paris, France; UMR CNRS 3569, 28 rue du Dr. Roux, 75015 Paris, France
| | - Laetitia Gerossier
- Inserm U1052, CNRS UMR5286, Centre de Recherche en Cancérologie de Lyon, Université de Lyon, F-69000 Lyon, France
| | - Aurélie Ducroux
- Unité des Hépacivirus et Immunité Innée, Institut Pasteur, 28 rue du Dr. Roux, 75015 Paris, France; UMR CNRS 3569, 28 rue du Dr. Roux, 75015 Paris, France; Institute for Experimental Virology, Group Innate Immunity and Viral Evasion, 30625 Hannover, Germany(†)
| | - Sarah Dion
- Laboratoire de Pathogenèse des Virus de l'Hépatite B, Département de Virologie, Institut Pasteur, 75015 Paris, France
| | - Qiang Deng
- Laboratoire de Pathogenèse des Virus de l'Hépatite B, Département de Virologie, Institut Pasteur, 75015 Paris, France; Laboratory of Molecular Virology and Immunology, Institute Pasteur of Shanghai, Chinese Academy of Sciences, Shanghai, China(†)
| | - Marie-Louise Michel
- Laboratoire de Pathogenèse des Virus de l'Hépatite B, Département de Virologie, Institut Pasteur, 75015 Paris, France
| | - Marie-Annick Buendia
- Inserm Unit U785, University Paris-Sud, Paul Brousse Hospital, 12 Avenue Paul Vaillant Couturier, 94800 Villejuif, France
| | - Olivier Hantz
- Inserm U1052, CNRS UMR5286, Centre de Recherche en Cancérologie de Lyon, Université de Lyon, F-69000 Lyon, France
| | - Christine Neuveut
- Unité des Hépacivirus et Immunité Innée, Institut Pasteur, 28 rue du Dr. Roux, 75015 Paris, France; UMR CNRS 3569, 28 rue du Dr. Roux, 75015 Paris, France.
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204
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Mapping of histone modifications in episomal HBV cccDNA uncovers an unusual chromatin organization amenable to epigenetic manipulation. Proc Natl Acad Sci U S A 2015; 112:E5715-24. [PMID: 26438841 DOI: 10.1073/pnas.1518090112] [Citation(s) in RCA: 171] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
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 because it does not directly affect nuclear HBV closed circular DNA (cccDNA), the genomic form that templates viral transcription and sustains viral persistence. Novel approaches that directly target cccDNA regulation 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, to our knowledge, 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 effect 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.
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205
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Abstract
HBV persists by depositing covalently closed circular DNA (cccDNA) into the nucleus of infected host cells. HBV X protein (HBx) is a crucial determinant for regulating HBV activity, but the molecular details have not been fully understood. A new role for HBx in regulating cccDNA transcription has now been identified.
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Affiliation(s)
- Ulrike Protzer
- Institute of Virology, Technische Universität München and the Helmholtz Zentrum München, Trogerstrasse 30, D-81675 München, Germany
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206
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Giersch K, Dandri M. Hepatitis B and Delta Virus: Advances on Studies about Interactions between the Two Viruses and the Infected Hepatocyte. J Clin Transl Hepatol 2015; 3:220-9. [PMID: 26623269 PMCID: PMC4663204 DOI: 10.14218/jcth.2015.00018] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/21/2015] [Revised: 07/11/2015] [Accepted: 07/12/2015] [Indexed: 12/14/2022] Open
Abstract
The mechanisms determining persistence of hepatitis B virus (HBV) infection and long-term pathogenesis of HBV-associated liver disease appear to be multifactorial. Although viral replication can be efficiently suppressed by the antiviral treatments currently available, viral clearance is generally not achieved since HBV has developed unique replication strategies, enabling persistence of its genome within the infected hepatocytes. Moreover, no direct antiviral therapy exists for the more than 15 million people worldwide that are also coinfected with the hepatitis delta virus (HDV), a defective virus that needs the HBV envelope proteins for propagation. The limited availability of robust HBV and HDV infection systems has hindered the understanding of the complex network of virus-virus and virus-host interactions that are established in the course of infection and slowed down progress in drug development. Since chronic HBV/HDV coinfection leads to the most severe form of chronic viral hepatitis, elucidation of the molecular mechanisms regulating virus-host interplay and pathogenesis are urgently needed. This article summarizes the current knowledge regarding the interactions among HBV, HDV, and the infected target cell and discusses the dependence of HDV on HBV activity and possible future therapeutic approaches.
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Affiliation(s)
- Katja Giersch
- Department of Internal Medicine, Center for Internal Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Maura Dandri
- Department of Internal Medicine, Center for Internal Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
- German Center for Infection Research (DZIF), Hamburg-Lübeck-Borstel site, Germany
- Correspondence to: Maura Dandri, Department of Internal Medicine, Center for Internal Medicine, University Medical Center Hamburg-Eppendorf, Martinistr. 52, D-20246 Hamburg, Germany. Tel: +49-40741052949, Fax: +49-40741057232, E-mail:
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207
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Fang CY, Shen CH, Wang M, Chen PL, Chan MW, Hsu PH, Chang D. Global profiling of histone modifications in the polyomavirus BK virion minichromosome. Virology 2015; 483:1-12. [DOI: 10.1016/j.virol.2015.04.009] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2014] [Revised: 01/05/2015] [Accepted: 04/08/2015] [Indexed: 01/05/2023]
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208
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Guo JT, Guo H. Metabolism and function of hepatitis B virus cccDNA: Implications for the development of cccDNA-targeting antiviral therapeutics. Antiviral Res 2015; 122:91-100. [PMID: 26272257 DOI: 10.1016/j.antiviral.2015.08.005] [Citation(s) in RCA: 115] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2015] [Accepted: 08/07/2015] [Indexed: 02/07/2023]
Abstract
Persistent hepatitis B virus (HBV) infection relies on the stable maintenance and proper functioning of a nuclear episomal form of the viral genome called covalently closed circular (ccc) DNA. One of the major reasons for the failure of currently available antiviral therapeutics to achieve a cure of chronic HBV infection is their inability to eradicate or inactivate cccDNA. In this review article, we summarize our current understanding of cccDNA metabolism in hepatocytes and the modulation of cccDNA by host pathophysiological and immunological cues. Perspectives on the future investigation of cccDNA biology, as well as strategies and progress in therapeutic elimination and/or transcriptional silencing of cccDNA through rational design and phenotypic screenings, are also discussed. This article forms part of a symposium in Antiviral Research on "An unfinished story: from the discovery of the Australia antigen to the development of new curative therapies for hepatitis B."
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Affiliation(s)
- Ju-Tao Guo
- Baruch S. Blumberg Institute, Hepatitis B Foundation, Doylestown, PA 18902, USA.
| | - Haitao Guo
- Department of Microbiology and Immunology, Indiana University School of Medicine, 635 Barnhill Drive, Indianapolis, IN 46202, USA.
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209
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Zeisel MB, Lucifora J, Mason WS, Sureau C, Beck J, Levrero M, Kann M, Knolle PA, Benkirane M, Durantel D, Michel ML, Autran B, Cosset FL, Strick-Marchand H, Trépo C, Kao JH, Carrat F, Lacombe K, Schinazi RF, Barré-Sinoussi F, Delfraissy JF, Zoulim F. Towards an HBV cure: state-of-the-art and unresolved questions--report of the ANRS workshop on HBV cure. Gut 2015; 64:1314-26. [PMID: 25670809 DOI: 10.1136/gutjnl-2014-308943] [Citation(s) in RCA: 207] [Impact Index Per Article: 23.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/03/2014] [Accepted: 01/10/2015] [Indexed: 12/11/2022]
Abstract
HBV infection is a major cause of liver cirrhosis and hepatocellular carcinoma. Although HBV infection can be efficiently prevented by vaccination, and treatments are available, to date there is no reliable cure for the >240 million individuals that are chronically infected worldwide. Current treatments can only achieve viral suppression, and lifelong therapy is needed in the majority of infected persons. In the framework of the French National Agency for Research on AIDS and Viral Hepatitis 'HBV Cure' programme, a scientific workshop was held in Paris in June 2014 to define the state-of-the-art and unanswered questions regarding HBV pathobiology, and to develop a concerted strategy towards an HBV cure. This review summarises our current understanding of HBV host-interactions leading to viral persistence, as well as the roadblocks to be overcome to ultimately address unmet medical needs in the treatment of chronic HBV infection.
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Affiliation(s)
- Mirjam B Zeisel
- Inserm, U1110, Institut de Recherche sur les Maladies Virales et Hépatiques, Strasbourg, France Université de Strasbourg, Strasbourg, France
| | - Julie Lucifora
- Inserm U1052, CNRS UMR 5286, Cancer Research Center of Lyon (CRCL), Université de Lyon (UCBL), Lyon, France
| | | | - Camille Sureau
- INTS, Laboratoire de Virologie Moléculaire, Paris, France
| | - Jürgen Beck
- Department of Internal Medicine 2/Molecular Biology, University Hospital Freiburg, Freiburg, Germany
| | - Massimo Levrero
- Center for Life Nanosciences (CNLS)-IIT/Sapienza, Rome, Italy Laboratory of Gene Expression, Department of Internal Medicine (DMISM), Sapienza University of Rome, Italy
| | - Michael Kann
- Université de Bordeaux, Microbiologie fondamentale et Pathogénicité, UMR 5234, Bordeaux, France CNRS, Microbiologie fondamentale et Pathogénicité, UMR 5234, Bordeaux, France CHU de Bordeaux, Bordeaux, France
| | - Percy A Knolle
- Technische Universität München, Institut für Molekulare Immunologie, München, Germany
| | - Monsef Benkirane
- Institut de Génétique Humaine, Laboratoire de Virologie Moléculaire, CNRS UPR1142, Montpellier, France
| | - David Durantel
- Inserm U1052, CNRS UMR 5286, Cancer Research Center of Lyon (CRCL), Université de Lyon (UCBL), Lyon, France
| | - Marie-Louise Michel
- Laboratoire de Pathogenèse des Virus de l'Hépatite B, Département de Virologie, Institut Pasteur, Paris, France
| | - Brigitte Autran
- Laboratory of Immunity and Infection, Inserm U945, Paris, France Laboratory of Immunity and Infection, UPMC University Paris 06, Unité mixte de recherche-S945, Paris, France Inserm, IFR 113, Immunité-Cancer-Infection, Paris, France
| | - François-Loïc Cosset
- CIRI-International Center for Infectiology Research, Team EVIR, Université de Lyon, Lyon, France. Inserm, U1111, Lyon, France Ecole Normale Supérieure de Lyon, Lyon, France. CNRS, UMR5308, Lyon, France LabEx Ecofect, Université de Lyon, Lyon, France
| | | | - Christian Trépo
- Inserm U1052, CNRS UMR 5286, Cancer Research Center of Lyon (CRCL), Université de Lyon (UCBL), Lyon, France Department of Hepatology, Croix-Rousse Hospital, Hospices Civils de Lyon, Lyon, France
| | - Jia-Horng Kao
- Department of Internal Medicine, Department of Medical Research, Graduate Institute of Clinical Medicine, and Hepatitis Research Center, National Taiwan University College of Medicine and Hospital, Taipei, Taiwan
| | - Fabrice Carrat
- Inserm, UMR_S 1136, Institut Pierre Louis d'Epidémiologie et de Santé Publique, Paris, France Sorbonne Universités, UPMC Univ Paris 06, Paris, France Assistance Publique Hôpitaux de Paris, Hôpital Saint Antoine, Paris, France
| | - Karine Lacombe
- Inserm, UMR_S 1136, Institut Pierre Louis d'Epidémiologie et de Santé Publique, Paris, France Sorbonne Universités, UPMC Univ Paris 06, Paris, France Assistance Publique Hôpitaux de Paris, Hôpital Saint Antoine, Paris, France
| | - Raymond F Schinazi
- Center for AIDS Research, Emory University School of Medicine and Veterans Affairs Medical Center, Atlanta, Georgia, USA
| | - Françoise Barré-Sinoussi
- Inserm and Unit of Regulation of Retroviral Infections, Department of Virology, Institut Pasteur, Paris, France
| | | | - Fabien Zoulim
- Inserm U1052, CNRS UMR 5286, Cancer Research Center of Lyon (CRCL), Université de Lyon (UCBL), Lyon, France Department of Hepatology, Croix-Rousse Hospital, Hospices Civils de Lyon, Lyon, France
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210
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Zlotnick A, Venkatakrishnan B, Tan Z, Lewellyn E, Turner W, Francis S. Core protein: A pleiotropic keystone in the HBV lifecycle. Antiviral Res 2015; 121:82-93. [PMID: 26129969 DOI: 10.1016/j.antiviral.2015.06.020] [Citation(s) in RCA: 190] [Impact Index Per Article: 21.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2015] [Revised: 06/22/2015] [Accepted: 06/26/2015] [Indexed: 12/21/2022]
Abstract
Hepatitis B Virus (HBV) is a small virus whose genome has only four open reading frames. We argue that the simplicity of the virion correlates with a complexity of functions for viral proteins. We focus on the HBV core protein (Cp), a small (183 residue) protein that self-assembles to form the viral capsid. However, its functions are a little more complicated than that. In an infected cell Cp modulates almost every step of the viral lifecycle. Cp is bound to nuclear viral DNA and affects its epigenetics. Cp correlates with RNA specificity. Cp assembles specifically on a reverse transcriptase-viral RNA complex or, apparently, nothing at all. Indeed Cp has been one of the model systems for investigation of virus self-assembly. Cp participates in regulation of reverse transcription. Cp signals completion of reverse transcription to support virus secretion. Cp carries both nuclear localization signals and HBV surface antigen (HBsAg) binding sites; both of these functions appear to be regulated by contents of the capsid. Cp can be targeted by antivirals - while self-assembly is the most accessible of Cp activities, we argue that it makes sense to engage the broader spectrum of Cp function. This article forms part of a symposium in Antiviral Research on "From the discovery of the Australia antigen to the development of new curative therapies for hepatitis B: an unfinished story."
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Affiliation(s)
- Adam Zlotnick
- Molecular & Cellular Biology, Indiana University, Bloomington, IN, United States.
| | | | - Zhenning Tan
- Assembly BioSciences, Bloomington, IN, United States; Assembly BioSciences, San Francisco, CA, United States
| | - Eric Lewellyn
- Assembly BioSciences, Bloomington, IN, United States; Assembly BioSciences, San Francisco, CA, United States
| | - William Turner
- Assembly BioSciences, Bloomington, IN, United States; Assembly BioSciences, San Francisco, CA, United States
| | - Samson Francis
- Molecular & Cellular Biology, Indiana University, Bloomington, IN, United States; Assembly BioSciences, Bloomington, IN, United States; Assembly BioSciences, San Francisco, CA, United States
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211
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Chen J, Wu M, Liu K, Zhang W, Li Y, Zhou X, Bai L, Yuan Z. New insights into hepatitis B virus biology and implications for novel antiviral strategies. Natl Sci Rev 2015. [DOI: 10.1093/nsr/nwv044] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Abstract
Hepatitis B virus (HBV), a small DNA virus with a unique replication mode, can cause chronic hepatitis (CHB), which is characterized by the persistence of the viral covalently closed circular DNA that serves as the template for HBV replication and the production of large amounts of secreted HBV surface antigen (HBsAg) that is present in excess of the levels of infectious virus. Despite the success of currently approved antiviral treatments for CHB patients, including interferon and nucleotide analogs, which suppress HBV replication and reduce the risk of CHB-related liver diseases, these therapies fail to eradicate the virus in most of the patients. With the development of the cell and animal models for HBV study, a better understanding of the HBV life cycle has been achieved and a series of novel antiviral strategies that target different stages of HBV replication have been designed to overcome the viral factors that contribute to HBV persistence. Such basic HBV research advancements and therapeutic developments are the subject of this review.
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Affiliation(s)
- Jieliang Chen
- Key Laboratory of Medical Molecular Virology, Ministry of Education and Health, and Department of Medical Microbiology, School of Basic Medical Sciences, Shanghai Medical College, Fudan University, Shanghai 200032, China
- Research Unit, Shanghai Public Health Clinical Center, Fudan University, Shanghai 201508, China
| | - Min Wu
- Research Unit, Shanghai Public Health Clinical Center, Fudan University, Shanghai 201508, China
| | - Kuancheng Liu
- Key Laboratory of Medical Molecular Virology, Ministry of Education and Health, and Department of Medical Microbiology, School of Basic Medical Sciences, Shanghai Medical College, Fudan University, Shanghai 200032, China
- Institutes of Medical Microbiology and Biomedical Sciences, Fudan University, Shanghai 200032, China
| | - Wen Zhang
- Key Laboratory of Medical Molecular Virology, Ministry of Education and Health, and Department of Medical Microbiology, School of Basic Medical Sciences, Shanghai Medical College, Fudan University, Shanghai 200032, China
- Research Unit, Shanghai Public Health Clinical Center, Fudan University, Shanghai 201508, China
| | - Yaming Li
- Key Laboratory of Medical Molecular Virology, Ministry of Education and Health, and Department of Medical Microbiology, School of Basic Medical Sciences, Shanghai Medical College, Fudan University, Shanghai 200032, China
| | - Xiaohui Zhou
- Research Unit, Shanghai Public Health Clinical Center, Fudan University, Shanghai 201508, China
| | - Lu Bai
- Key Laboratory of Medical Molecular Virology, Ministry of Education and Health, and Department of Medical Microbiology, School of Basic Medical Sciences, Shanghai Medical College, Fudan University, Shanghai 200032, China
| | - Zhenghong Yuan
- Key Laboratory of Medical Molecular Virology, Ministry of Education and Health, and Department of Medical Microbiology, School of Basic Medical Sciences, Shanghai Medical College, Fudan University, Shanghai 200032, China
- Institutes of Medical Microbiology and Biomedical Sciences, Fudan University, Shanghai 200032, China
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212
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Xiang A, Ren F, Lei X, Zhang J, Guo R, Lu Z, Guo Y. The hepatitis B virus (HBV) core protein enhances the transcription activation of CRE via the CRE/CREB/CBP pathway. Antiviral Res 2015; 120:7-15. [PMID: 25936964 DOI: 10.1016/j.antiviral.2015.04.013] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2014] [Revised: 04/16/2015] [Accepted: 04/21/2015] [Indexed: 12/21/2022]
Abstract
We previously reported that hepatitis B virus core protein (HBc) can bind to the Enhancer I (Enh I) domain and can accumulate with transcription coactivator cAMP response element (CRE). This raises the possibility that HBc may interact with CRE/CREB and regulate CRE transcription activation. In this study, we investigated the function and mechanisms of HBc in regulating CRE transcriptional activation using the HepG2 cell line. Our results showed the following: (1) HBc expression significantly increases HBV CRE transcriptional activation; (2) phosphorylation of the serine residues in the arginine-rich domain (ARD) of HBc protein impacts the function of transcriptional activation by the CRE; (3) HBc protein significantly increases HBV CRE transcriptional activation following forskolin treatment; (4) HBc nonspecifically binds to CRE and enhances the binding of the cAMP response element-binding protein (CREB) to CRE; and (5) HBc increases the concurrent accumulation of CREB and CBP at the CRE region. HBc activates Enh I through its binding to CRE, increasing the concurrent accumulation of CREB/CBP on CRE, and thus increases CRE transcriptional activation.
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Affiliation(s)
- An Xiang
- School of Pharmacology, The Fourth Military Medical University, Xi'an 710032, China
| | - Fengling Ren
- School of Public Health, Xi'an Jiaotong University, Xi'an 710061, China
| | - Xiaoying Lei
- School of Pharmacology, The Fourth Military Medical University, Xi'an 710032, China
| | - Ju Zhang
- School of Pharmacology, The Fourth Military Medical University, Xi'an 710032, China
| | - Ruijuan Guo
- School of Pharmacology, The Fourth Military Medical University, Xi'an 710032, China
| | - Zifan Lu
- School of Pharmacology, The Fourth Military Medical University, Xi'an 710032, China
| | - Yanhai Guo
- School of Pharmacology, The Fourth Military Medical University, Xi'an 710032, China
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213
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Seeger C, Mason WS. Molecular biology of hepatitis B virus infection. Virology 2015; 479-480:672-86. [PMID: 25759099 PMCID: PMC4424072 DOI: 10.1016/j.virol.2015.02.031] [Citation(s) in RCA: 566] [Impact Index Per Article: 62.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2015] [Revised: 02/09/2015] [Accepted: 02/16/2015] [Indexed: 02/06/2023]
Abstract
Human hepatitis B virus (HBV) is the prototype of a family of small DNA viruses that productively infect hepatocytes, the major cell of the liver, and replicate by reverse transcription of a terminally redundant viral RNA, the pregenome. Upon infection, the circular, partially double-stranded virion DNA is converted in the nucleus to a covalently closed circular DNA (cccDNA) that assembles into a minichromosome, the template for viral mRNA synthesis. Infection of hepatocytes is non-cytopathic. Infection of the liver may be either transient (<6 months) or chronic and lifelong, depending on the ability of the host immune response to clear the infection. Chronic infections can cause immune-mediated liver damage progressing to cirrhosis and hepatocellular carcinoma (HCC). The mechanisms of carcinogenesis are unclear. Antiviral therapies with nucleoside analog inhibitors of viral DNA synthesis delay sequelae, but cannot cure HBV infections due to the persistence of cccDNA in hepatocytes.
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214
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Oh J, Sanders IF, Chen EZ, Li H, Tobias JW, Isett RB, Penubarthi S, Sun H, Baldwin DA, Fraser NW. Genome wide nucleosome mapping for HSV-1 shows nucleosomes are deposited at preferred positions during lytic infection. PLoS One 2015; 10:e0117471. [PMID: 25710170 PMCID: PMC4339549 DOI: 10.1371/journal.pone.0117471] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2014] [Accepted: 12/23/2014] [Indexed: 01/01/2023] Open
Abstract
HSV is a large double stranded DNA virus, capable of causing a variety of diseases from the common cold sore to devastating encephalitis. Although DNA within the HSV virion does not contain any histone protein, within 1 h of infecting a cell and entering its nucleus the viral genome acquires some histone protein (nucleosomes). During lytic infection, partial micrococcal nuclease (MNase) digestion does not give the classic ladder band pattern, seen on digestion of cell DNA or latent viral DNA. However, complete digestion does give a mono-nucleosome band, strongly suggesting that there are some nucleosomes present on the viral genome during the lytic infection, but that they are not evenly positioned, with a 200 bp repeat pattern, like cell DNA. Where then are the nucleosomes positioned? Here we perform HSV-1 genome wide nucleosome mapping, at a time when viral replication is in full swing (6 hr PI), using a microarray consisting of 50mer oligonucleotides, covering the whole viral genome (152 kb). Arrays were probed with MNase-protected fragments of DNA from infected cells. Cells were not treated with crosslinking agents, thus we are only mapping tightly bound nucleosomes. The data show that nucleosome deposition is not random. The distribution of signal on the arrays suggest that nucleosomes are located at preferred positions on the genome, and that there are some positions that are not occupied (nucleosome free regions -NFR or Nucleosome depleted regions -NDR), or occupied at frequency below our limit of detection in the population of genomes. Occupancy of only a fraction of the possible sites may explain the lack of a typical MNase partial digestion band ladder pattern for HSV DNA during lytic infection. On average, DNA encoding Immediate Early (IE), Early (E) and Late (L) genes appear to have a similar density of nucleosomes.
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Affiliation(s)
- Jaewook Oh
- Department of Microbiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, United States of America
| | - Iryna F. Sanders
- Department of Microbiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, United States of America
| | - Eric Z. Chen
- Department of Chemical Pathology, The Chinese University of Hong Kong, Li Ka Shing Institute of Health Sciences, Hong Kong SAR, China
- Department of Biostatistics and Epidemiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, United States of America
| | - Hongzhe Li
- Department of Biostatistics and Epidemiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, United States of America
| | - John W. Tobias
- Penn Molecular Profiling Facility, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, United States of America
| | - R. Benjamin Isett
- Penn Molecular Profiling Facility, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, United States of America
| | - Sindura Penubarthi
- Department of Microbiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, United States of America
| | - Hao Sun
- Department of Chemical Pathology, The Chinese University of Hong Kong, Li Ka Shing Institute of Health Sciences, Hong Kong SAR, China
| | - Don A. Baldwin
- Pathonomics LLC, Philadelphia, PA, 19104, United States of America
| | - Nigel W. Fraser
- Department of Microbiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, United States of America
- * E-mail:
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215
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Transbody against hepatitis B virus core protein inhibits hepatitis B virus replication in vitro. Int Immunopharmacol 2015; 25:363-9. [PMID: 25676532 DOI: 10.1016/j.intimp.2015.01.028] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2014] [Revised: 01/14/2015] [Accepted: 01/29/2015] [Indexed: 02/08/2023]
Abstract
Hepatitis B virus (HBV) infection is one of the major causes of chronic liver diseases. The current therapeutics show limited efficacy. In the HBV life cycle, virus core antigen (HBcAg) plays important multiple roles. Blocking the pleiotropic functions of HBcAg may thus represent a promising strategy for anti-HBV replication. In this study, monoclonal antibody (MAb) against core antigen of human HBV was coupled with TAT protein transduction domain (TAT PTD) to form transbody, and the effect on virus replication was evaluated in vitro. The HBV transbody, HBcMAb-TAT PTD conjugate, recognized HBcAg and retained cell-penetrating activity in living cells. In HBV-transfected liver cell line HepG2.2.15, HBV transbody suppressed not only the extracellular HBsAg, HBeAg and HBV DNA, but also the intracellular HBsAg, HBeAg, HBcAg and HBV DNA in a dose-dependent manner. These results indicate that the transbody prepared possesses readily cell-penetrating ability and potent antiviral activity, providing a novel approach, a cell-permeable antibody against HBcAg, for the treatment of HBV infection.
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216
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Targeting the Achilles heel of the hepatitis B virus: a review of current treatments against covalently closed circular DNA. Drug Discov Today 2015; 20:548-61. [PMID: 25622780 DOI: 10.1016/j.drudis.2015.01.008] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2014] [Revised: 12/15/2014] [Accepted: 01/14/2015] [Indexed: 01/05/2023]
Abstract
Chronic infection with hepatitis B virus (HBV) often leads to the development of liver cancer and cirrhosis, creating immense sociological, clinical and economic burdens worldwide. Although current anti-HBV medications manage to control the disease progression and help restore normal liver functions, they often fail to eliminate the virus completely. A major reason for this failure is the presence of a stable viral genome in the hepatocyte nucleus: the covalently closed circular DNA (cccDNA). Targeting HBV cccDNA is a promising approach that could lead to a complete cure. Here, we review various research approaches that are directed toward eliminating HBV cccDNA. This is a brief, yet comprehensive, summary of current state-of-the-art developments in this emerging area of interest.
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217
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Transcription of hepatitis B virus covalently closed circular DNA is regulated by CpG methylation during chronic infection. PLoS One 2014; 9:e110442. [PMID: 25337821 PMCID: PMC4206413 DOI: 10.1371/journal.pone.0110442] [Citation(s) in RCA: 70] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2014] [Accepted: 09/12/2014] [Indexed: 02/07/2023] Open
Abstract
The persistence of hepatitis B virus (HBV) infection is maintained by the nuclear viral covalently closed circular DNA (cccDNA), which serves as transcription template for viral mRNAs. Previous studies suggested that cccDNA contains methylation-prone CpG islands, and that the minichromosome structure of cccDNA is epigenetically regulated by DNA methylation. However, the regulatory effect of each CpG island methylation on cccDNA activity remains elusive. In the present study, we analyzed the distribution of CpG methylation within cccDNA in patient samples and investigated the impact of CpG island methylation on cccDNA-driven virus replication. Our study revealed the following observations: 1) Bisulfite sequencing of cccDNA from chronic hepatitis B patients indicated that CpG island I was seldom methylated, 2) CpG island II methylation was correlated to the low level of serum HBV DNA in patients, and in vitro methylation studies confirmed that CpG island II methylation markedly reduced cccDNA transcription and subsequent viral core DNA replication, 3) CpG island III methylation was associated with low serum HBsAg titers, and 4) Furthermore, we found that HBV genotype, HBeAg positivity, and patient age and liver fibrosis stage were also relevant to cccDNA CpG methylation status. Therefore, we clearly demonstrated that the status of cccDNA methylation is connected to the biological behavior of HBV. Taken together, our study provides a complete profile of CpG island methylation within HBV cccDNA and new insights for the function of CpG methylation in regulating HBV cccDNA transcription.
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218
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Tong HV, Thomas Bock C, Velavan TP. Genetic insights on host and hepatitis B virus in liver diseases. MUTATION RESEARCH-REVIEWS IN MUTATION RESEARCH 2014; 762:65-75. [PMID: 25475418 DOI: 10.1016/j.mrrev.2014.06.001] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/04/2014] [Revised: 06/16/2014] [Accepted: 06/17/2014] [Indexed: 02/08/2023]
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219
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Yang HC, Kao JH. Persistence of hepatitis B virus covalently closed circular DNA in hepatocytes: molecular mechanisms and clinical significance. Emerg Microbes Infect 2014; 3:e64. [PMID: 26038757 PMCID: PMC4185362 DOI: 10.1038/emi.2014.64] [Citation(s) in RCA: 92] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2014] [Revised: 07/17/2014] [Accepted: 07/21/2014] [Indexed: 02/06/2023]
Abstract
Covalently closed circular DNA (cccDNA) is the transcriptional template of hepatitis B virus (HBV). Extensive research over the past decades has unveiled the important role of cccDNA in the natural history and antiviral treatment of chronic HBV infection. cccDNA can persist in patients recovering from acute HBV infection for decades. This explains why HBV reactivation occasionally occurs in patients with resolved hepatitis B receiving intensive immunosuppressive agents. In addition, although advances in antiviral treatment dramatically improve the adverse outcomes of chronic hepatitis B (CHB), accumulating evidence demonstrates that current antiviral treatments alone, be they nucleos(t)ide analogs (NAs) or interferon (IFN), fail to cure most CHB patients because of the persistent cccDNA. NA suppresses HBV replication by directly inhibiting viral polymerase, while IFN enhances host immunity against HBV infection. Viral rebound often occurs after discontinuation of antiviral treatment. The loss of cccDNA can be induced by non-cytolytic destruction of cccDNA or immune-mediated killing of infected hepatocytes. It is known that NA has no direct effect on viral transcription or cccDNA stability. Therefore, the long half-life of hepatocytes leads to a very slow decline in cccDNA in patients under antiviral therapy. Novel antiviral agents targeting cccDNA or cccDNA-containing hepatocytes are thus required for curing chronic HBV infection.
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Affiliation(s)
- Hung-Chih Yang
- Department of Microbiology, National Taiwan University College of Medicine , Taipei 10002, Taiwan, China ; Graduate Institute of Clinical Medicine, National Taiwan University College of Medicine , Taipei 10002, Taiwan, China ; Department of Internal Medicine, National Taiwan University Hospital , Taipei 10002, Taiwan, China
| | - Jia-Horng Kao
- Graduate Institute of Clinical Medicine, National Taiwan University College of Medicine , Taipei 10002, Taiwan, China ; Department of Internal Medicine, National Taiwan University Hospital , Taipei 10002, Taiwan, China ; Hepatitis Research Center, National Taiwan University Hospital , Taipei 10002, Taiwan, China ; Department of Medical Research, National Taiwan University Hospital , Taipei 10002, Taiwan, China
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220
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Lucifora J, Xia Y, Reisinger F, Stadler D, Heikenwälder M, Protzer U. [Specific degradation of nuclear hepatitis B virus covalently closed circular DNA]. Med Sci (Paris) 2014; 30:724-6. [PMID: 25174742 DOI: 10.1051/medsci/20143008003] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Affiliation(s)
- Julie Lucifora
- Institute of Virology, Technische Universität München/Helmholtz Zentrum München, Munich, Allemagne - German Center for Infection Research (DZIF), Allemagne - affiliation actuelle : Inserm U1052, CNRS UMR 5286, centre de recherche en cancérologie de Lyon (CRCL), Université de Lyon (UCBL), Lyon, France
| | - Yuchen Xia
- Institute of Virology, Technische Universität München/Helmholtz Zentrum München, Munich, Allemagne
| | - Florian Reisinger
- Institute of Virology, Technische Universität München/Helmholtz Zentrum München, Munich, Allemagne
| | - Daniela Stadler
- Institute of Virology, Technische Universität München/Helmholtz Zentrum München, Munich, Allemagne
| | - Mathias Heikenwälder
- Institute of Virology, Technische Universität München/Helmholtz Zentrum München, Munich, Allemagne
| | - Ulrike Protzer
- Institute of Virology, Technische Universität München/Helmholtz Zentrum München, Munich, Allemagne - German Center for Infection Research (DZIF), Allemagne
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221
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Lazarevic I. Clinical implications of hepatitis B virus mutations: Recent advances. World J Gastroenterol 2014; 20:7653-7664. [PMID: 24976703 PMCID: PMC4069294 DOI: 10.3748/wjg.v20.i24.7653] [Citation(s) in RCA: 91] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/28/2013] [Revised: 01/05/2014] [Accepted: 03/05/2014] [Indexed: 02/06/2023] Open
Abstract
Hepatitis B virus (HBV) infection is a major cause of acute and chronic hepatitis, and of its long-term complications. It is the most variable among DNA viruses, mostly because of its unique life cycle which includes the activity of error-prone enzyme, reverse transcriptase, and the very high virion production per day. In last two decades, numerous research studies have shown that the speed of disease progression, reliability of diagnostic methods and the success of antiviral therapy and immunization are all influenced by genetic variability of this virus. It was shown that mutations in specific regions of HBV genome could be responsible for unwanted clinical outcomes or evasion of detection by diagnostic tools, thus making the monitoring for these mutations a necessity in proper evaluation of patients. The success of the vaccination programs has now been challenged by the discovery of mutant viruses showing amino acid substitutions in hepatitis B surface antigen (HBsAg), which may lead to evasion of vaccine-induced immunity. However, the emergence of these mutations has not yet raised concern since it was shown that they develop slowly. Investigations of HBV genetic variability and clinical implications of specific mutations have resulted in significant advances over the past decade, particularly in regard to management of resistance to antiviral drugs. In the era of drugs with high genetic barrier for resistance, on-going monitoring for possible resistance is still essential since prolonged therapy is often necessary. Understanding the frequencies and clinical implications of viral mutations may contribute to improvement of diagnostic procedures, more proper planning of immunization programs and creating the most efficient therapeutic protocols.
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222
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Recombinant covalently closed circular hepatitis B virus DNA induces prolonged viral persistence in immunocompetent mice. J Virol 2014; 88:8045-56. [PMID: 24807718 DOI: 10.1128/jvi.01024-14] [Citation(s) in RCA: 77] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
It remains crucial to develop a laboratory model for studying hepatitis B virus (HBV) chronic infection. We hereby produced a recombinant covalently closed circular DNA (rcccDNA) in view of the key role of cccDNA in HBV persistence. A loxP-chimeric intron was engineered into a monomeric HBV genome in a precursor plasmid (prcccDNA), which was excised using Cre/loxP-mediated DNA recombination into a 3.3-kb rcccDNA in the nuclei of hepatocytes. The chimeric intron was spliced from RNA transcripts without interrupting the HBV life cycle. In cultured hepatoma cells, cotransfection of prcccDNA and pCMV-Cre (encoding Cre recombinase) resulted in accumulation of nuclear rcccDNA that was heat stable and epigenetically organized as a minichromosome. A mouse model of HBV infection was developed by hydrodynamic injection of prcccDNA. In the presence of Cre recombinase, rcccDNA was induced in the mouse liver with effective viral replication and expression, triggering a compromised T-cell response against HBV. Significant T-cell hyporesponsiveness occurred in mice receiving 4 μg prcccDNA, resulting in prolonged HBV antigenemia for up to 9 weeks. Persistent liver injury was observed as elevated alanine transaminase activity in serum and sustained inflammatory infiltration in the liver. Although a T-cell dysfunction was induced similarly, mice injected with a plasmid containing a linear HBV replicon showed rapid viral clearance within 2 weeks. Collectively, our study provides an innovative approach for producing a cccDNA surrogate that established HBV persistence in immunocompetent mice. It also represents a useful model system in vitro and in vivo for evaluating antiviral treatments against HBV cccDNA. Importance: (i) Unlike plasmids that contain a linear HBV replicon, rcccDNA established HBV persistence with sustained liver injury in immunocompetent mice. This method could be a prototype for developing a mouse model of chronic HBV infection. (ii) An exogenous intron was engineered into the HBV genome for functionally seamless DNA recombination. This original approach could be also extended to other viral studies. (iii) rcccDNA was substantially induced in the nuclei of hepatocytes and could be easily distinguished by its exogenous intron using PCR. This convenient model system affords the opportunity to test antivirals directly targeting HBV cccDNA.
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223
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Taranta A, Tien Sy B, Zacher BJ, Rogalska-Taranta M, Manns MP, Bock CT, Wursthorn K. Hepatitis B virus DNA quantification with the three-in-one (3io) method allows accurate single-step differentiation of total HBV DNA and cccDNA in biopsy-size liver samples. J Clin Virol 2014; 60:354-60. [PMID: 24890819 DOI: 10.1016/j.jcv.2014.04.015] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2014] [Revised: 04/21/2014] [Accepted: 04/22/2014] [Indexed: 02/07/2023]
Abstract
BACKGROUND Hepatitis B virus (HBV) replicates via reverse transcription converting its partially double stranded genome into the covalently closed circular DNA (cccDNA). The long-lasting cccDNA serves as a replication intermediate in the nuclei of hepatocytes. It is an excellent, though evasive, parameter for monitoring the course of liver disease and treatment efficiency. OBJECTIVE To develop and test a new approach for HBV DNA quantification in serum and small-size liver samples. STUDY DESIGN The p3io plasmid contains an HBV fragment and human β-actin gene (hACTB) as a standard. Respective TaqMan probes were labeled with different fluorescent dyes. A triplex real-time PCR for simultaneous quantification of total HBV DNA, cccDNA and hACTB could be established. RESULTS Three-in-one method allows simultaneous analysis of 3 targets with a lower limit of quantification of 48 copies per 20 μl PCR reaction and a wide range of linearity (R(2)>0.99, p<0.0001) for all measured sequences. The method showed a pan-genotypic specificity among genotypes A-F with serum DNA samples from HBV infected patients. Total HBV DNA and cccDNA could be quantified in 32 and 22 of 33 FFPE preserved liver specimens, respectively. Total HBV DNA concentrations quantified by the 3io method remained comparable with Cobas TaqMan HBV Test v2.0. CONCLUSIONS The three-in-one protocol allows the single step quantification of viral DNA in samples from different sources. Therefore lower sample input, faster data acquisition, a lowered error and significantly lower costs are the advantages of the method.
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Affiliation(s)
- Andrzej Taranta
- Hannover Medical School (MHH), Department of Gastroenterology, Hepatology and Endocrinology, Carl-Neuberg-Straße 1, 30623 Hannover, Germany
| | - Bui Tien Sy
- Robert Koch Institute, Department of Infectious Diseases, Seestraße 10, 13353 Berlin, Germany; Institute of Tropical Medicine, University of Tuebingen, Wilhelmstraße 27D, 72074 Tübingen, Germany
| | - Behrend Johan Zacher
- Hannover Medical School (MHH), Department of Gastroenterology, Hepatology and Endocrinology, Carl-Neuberg-Straße 1, 30623 Hannover, Germany
| | - Magdalena Rogalska-Taranta
- Hannover Medical School (MHH), Department of Gastroenterology, Hepatology and Endocrinology, Carl-Neuberg-Straße 1, 30623 Hannover, Germany; Department of Infectious Diseases and Hepatology, Medical University of Bialystok, Żurawia 14, 15540 Białystok, Poland
| | - Michael Peter Manns
- Hannover Medical School (MHH), Department of Gastroenterology, Hepatology and Endocrinology, Carl-Neuberg-Straße 1, 30623 Hannover, Germany
| | - Claus Thomas Bock
- Robert Koch Institute, Department of Infectious Diseases, Seestraße 10, 13353 Berlin, Germany
| | - Karsten Wursthorn
- Hannover Medical School (MHH), Department of Gastroenterology, Hepatology and Endocrinology, Carl-Neuberg-Straße 1, 30623 Hannover, Germany; ifi - Institut für Interdisziplinäre Medizin, Lohmühlenstraße. 5, 20099 Hamburg, Germany.
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224
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Occult HBV infection: a faceless enemy in liver cancer development. Viruses 2014; 6:1590-611. [PMID: 24717680 PMCID: PMC4014712 DOI: 10.3390/v6041590] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2014] [Revised: 03/13/2014] [Accepted: 03/20/2014] [Indexed: 12/12/2022] Open
Abstract
The hepatitis B virus (HBV) represents a worldwide public health problem; the virus is present in one third of the global population. However, this rate may in fact be higher due to occult hepatitis B virus infection (OBI). This condition is characterized by the presence of the viral genome in the liver of individuals sero-negative for the virus surface antigen (HBsAg). The causes of the absence of HBsAg in serum are unknown, however, mutations have been identified that produce variants not recognized by current immunoassays. Epigenetic and immunological host mechanisms also appear to be involved in HBsAg suppression. Current evidence suggests that OBI maintains its carcinogenic potential, favoring the progression of fibrosis and cirrhosis of the liver. In common with open HBV infection, OBI can contribute to the establishment of hepatocellular carcinoma. Epidemiological data regarding the global prevalence of OBI vary due to the use of detection methods of different sensitivity and specificity. In Latin America, which is considered an area of low prevalence for HBV, diagnostic screening methods using gene amplification tests for confirmation of OBI are not conducted. This prevents determination of the actual prevalence of OBI, highlighting the need for the implementation of cutting edge technology in epidemiological surveillance systems.
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225
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Lucifora J, Xia Y, Reisinger F, Zhang K, Stadler D, Cheng X, Sprinzl MF, Koppensteiner H, Makowska Z, Volz T, Remouchamps C, Chou WM, Thasler WE, Hüser N, Durantel D, Liang TJ, Münk C, Heim MH, Browning JL, Dejardin E, Dandri M, Schindler M, Heikenwalder M, Protzer U. Specific and nonhepatotoxic degradation of nuclear hepatitis B virus cccDNA. Science 2014; 343:1221-8. [PMID: 24557838 DOI: 10.1126/science.1243462] [Citation(s) in RCA: 703] [Impact Index Per Article: 70.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Current antiviral agents can control but not eliminate hepatitis B virus (HBV), because HBV establishes a stable nuclear covalently closed circular DNA (cccDNA). Interferon-α treatment can clear HBV but is limited by systemic side effects. We describe how interferon-α can induce specific degradation of the nuclear viral DNA without hepatotoxicity and propose lymphotoxin-β receptor activation as a therapeutic alternative. Interferon-α and lymphotoxin-β receptor activation up-regulated APOBEC3A and APOBEC3B cytidine deaminases, respectively, in HBV-infected cells, primary hepatocytes, and human liver needle biopsies. HBV core protein mediated the interaction with nuclear cccDNA, resulting in cytidine deamination, apurinic/apyrimidinic site formation, and finally cccDNA degradation that prevented HBV reactivation. Genomic DNA was not affected. Thus, inducing nuclear deaminases-for example, by lymphotoxin-β receptor activation-allows the development of new therapeutics that, in combination with existing antivirals, may cure hepatitis B.
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Affiliation(s)
- Julie Lucifora
- Institute of Virology, Technische Universität München-Helmholtz Zentrum München, 81675 Munich, Germany
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226
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Zhang X, Hou J, Lu M. Regulation of hepatitis B virus replication by epigenetic mechanisms and microRNAs. Front Genet 2013; 4:202. [PMID: 24133502 PMCID: PMC3796260 DOI: 10.3389/fgene.2013.00202] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2013] [Accepted: 09/22/2013] [Indexed: 12/17/2022] Open
Abstract
The hepatitis B virus (HBV) genome forms a covalently closed circular DNA (cccDNA) minichromosome that persists in the nucleus of virus-infected hepatocytes. HBV cccDNA serves as the template for viral mRNA synthesis and is subject to epigenetic regulation by several mechanisms, including DNA methylation and histone acetylation. Recently, microRNAs (miRNAs), a class of small non-coding RNAs, were also directly connected to the epigenetic machinery through a regulatory loop. Epigenetic modifications have been shown to affect miRNA expression, and a sub-group of miRNAs (defined as epi-miRNAs) can directly target effectors of the epigenetic machinery. In this review, we will summarize recent findings on the epigenetic mechanisms controlling HBV cccDNA function, primarily focusing on the epi-miRNA functions operating in HBV replication. Investigation of the epigenetic regulation of HBV replication may help to discover novel potential therapeutic targets for drug development with the goal to eradicate the HBV cccDNA pool in hepatocytes.
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Affiliation(s)
- Xiaoyong Zhang
- Hepatology Unit and Department of Infectious Diseases, Nanfang Hospital, Southern Medical University Guangzhou, China ; Institute of Virology, University Hospital of Essen, University of Duisburg Essen Essen, Germany
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227
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Hu Y, Zhu W, Tang G, Mayweg AV, Yang G, Wu JZ, Shen HC. Novel Therapeutics in Discovery and Development for Treatment of Chronic HBV Infection. ANNUAL REPORTS IN MEDICINAL CHEMISTRY 2013. [DOI: 10.1016/b978-0-12-417150-3.00017-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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228
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van Breugel PC, Robert EI, Mueller H, Decorsière A, Zoulim F, Hantz O, Strubin M. Hepatitis B virus X protein stimulates gene expression selectively from extrachromosomal DNA templates. Hepatology 2012; 56:2116-24. [PMID: 22744635 DOI: 10.1002/hep.25928] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/04/2012] [Accepted: 06/15/2012] [Indexed: 12/22/2022]
Abstract
UNLABELLED Chronic hepatitis B virus (HBV) infection is a major risk factor for liver cancer development. HBV encodes the hepatitis B virus X (HBx) protein that promotes transcription of the viral episomal DNA genome by the host cell RNA polymerase II. Here we provide evidence that HBx accomplishes this task by a conserved and unusual mechanism. Thus, HBx strongly stimulates expression of transiently transfected reporter constructs, regardless of the enhancer and promoter sequences. This activity invariably requires HBx binding to the cellular UV-damaged DDB1 E3 ubiquitin ligase, suggesting a common mechanism. Unexpectedly, none of the reporters tested is stimulated by HBx when integrated into the chromosome, despite remaining responsive to their cognate activators. Likewise, HBx promotes gene expression from the natural HBV episomal template but not from a chromosomally integrated HBV construct. The same was observed with the HBx protein of woodchuck HBV. HBx does not affect nuclear plasmid copy number and functions independently of CpG dinucleotide methylation. CONCLUSION We propose that HBx supports HBV gene expression by a conserved mechanism that acts specifically on episomal DNA templates independently of the nature of the cis-regulatory sequences. Because of its uncommon property and key role in viral transcription, HBx represents an attractive target for new antiviral therapies.
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Affiliation(s)
- Pieter C van Breugel
- Department of Microbiology and Molecular Medicine, University Medical Centre (C.M.U.), Geneva, Switzerland
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229
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Luo L, Chen S, Gong Q, Luo N, Lei Y, Guo J, He S. Hepatitis B virus X protein modulates remodelling of minichromosomes related to hepatitis B virus replication in HepG2 cells. Int J Mol Med 2012; 31:197-204. [PMID: 23128981 DOI: 10.3892/ijmm.2012.1165] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2012] [Accepted: 08/14/2012] [Indexed: 11/05/2022] Open
Abstract
Hepatitis B virus (HBV) covalently closed circular DNA (cccDNA) is organised into minichromosomes by histone and non-histone proteins. Remodelling of minichromosomes is crucial for the regulation of HBV replication, which is dependent on the presence of the hepatitis B virus X protein (HBx). However, the mechanisms of HBx-dependent HBV replication remain obscure. The objective of this study was to investigate the mechanism of HBx-dependent HBV replication through the pathway of chromatin remodelling. The role of HBx was investigated by transfecting human HepG2 cells with the linear full-length HBV genome (wild-type) or HBx-deficient mutant HBV DNA (HBx mutant). Our results showed that although the formation of cccDNA was not affected by HBx, HBV replication, transcription and antigen secretion were all significantly reduced, resulting from the absence of HBx. The acetylation, mono-methylation and phosphorylation of cccDNA-bound histone H3 were associated with HBV replication. In addition, the levels of cccDNA-bound methylated, phosphorylated and acetylated histone H3 decreased sharply in HBx mutant HBV DNA. HBx modulated not only the status of acetylation but also the methylation and phosphorylation of histone H3 bound to the cccDNA during HBV replication in HepG2 cells. These findings suggest that HBx plays an important role in modulating the remodelling of minichromosomes related to HBV replication and it may regulate viral replication through the pathway of chromatin remodelling.
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Affiliation(s)
- Li Luo
- Department of Gastroenterology, The Second Affiliated Hospital of Chongqing Medical University, Chongqing, PR China
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230
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Guo Y, Kang W, Lei X, Li Y, Xiang A, Liu Y, Zhao J, Zhang J, Yan Z. Hepatitis B viral core protein disrupts human host gene expression by binding to promoter regions. BMC Genomics 2012; 13:563. [PMID: 23088787 PMCID: PMC3484065 DOI: 10.1186/1471-2164-13-563] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2012] [Accepted: 10/15/2012] [Indexed: 02/07/2023] Open
Abstract
BACKGROUND The core protein (HBc) of hepatitis B virus (HBV) has been implicated in the malignant transformation of chronically-infected hepatocytes and displays pleiotropic functions, including RNA- and DNA-binding activities. However, the mechanism by which HBc interacts with the human genome to exert effects on hepatocyte function remains unknown. This study investigated the distribution of HBc binding to promoters in the human genome and evaluated its effects on the related genes' expression. RESULTS Whole-genome chromatin immunoprecipitation microarray (ChIP-on-chip) analysis was used to identify HBc-bound human gene promoters. Gene Ontology and pathway analyses were performed on related genes. The quantitative polymerase chain reaction assay was used to verify ChIP-on-chip results. Five novel genes were selected for luciferase reporter assay evaluation to assess the influence of HBc promoter binding. The HBc antibody immunoprecipitated approximately 3100 human gene promoters. Among these, 1993 are associated with known biological processes, and 2208 regulate genes with defined molecular functions. In total, 1286 of the related genes mediate primary metabolic processes, and 1398 encode proteins with binding activity. Sixty-four of the promoters regulate genes related to the mitogen-activated protein kinase (MAPK) pathways, and 41 regulate Wnt/beta-catenin pathway genes. The reporter gene assay indicated that HBc binding up-regulates proto-oncogene tyrosine-protein kinase (SRC), type 1 insulin-like growth factor receptor (IGF1R), and neurotrophic tyrosine kinase receptor 2 (NTRK2), and down-regulates v-Ha-ras Harvey rat sarcoma viral oncogene (HRAS). CONCLUSION HBc has the ability to bind a large number of human gene promoters, and can disrupt normal host gene expression. Manipulation of the transcriptional profile in HBV-infected hepatocytes may represent a key pathogenic mechanism of HBV infection.
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Affiliation(s)
- Yanhai Guo
- State Key Laboratory of Cancer Biology, Department of Pharmacogenomics, School of Pharmacy, Fourth Military Medical University, 169 West Changle Road, Xi’an, 710032, China
| | - Wei Kang
- Department of Clinical Laboratory, Affiliated Hospital of Xi’an Medical University, Xi’an, 710077, China
| | - Xiaoying Lei
- State Key Laboratory of Cancer Biology, Department of Pharmacogenomics, School of Pharmacy, Fourth Military Medical University, 169 West Changle Road, Xi’an, 710032, China
| | - Yongnian Li
- Department of Infectious Diseases, 323 Hospital, Xi’an, 710000, China
| | - An Xiang
- State Key Laboratory of Cancer Biology, Department of Pharmacogenomics, School of Pharmacy, Fourth Military Medical University, 169 West Changle Road, Xi’an, 710032, China
| | - Yonglan Liu
- State Key Laboratory of Cancer Biology, Department of Pharmacogenomics, School of Pharmacy, Fourth Military Medical University, 169 West Changle Road, Xi’an, 710032, China
| | - Jinrong Zhao
- State Key Laboratory of Cancer Biology, Department of Pharmacogenomics, School of Pharmacy, Fourth Military Medical University, 169 West Changle Road, Xi’an, 710032, China
| | - Ju Zhang
- State Key Laboratory of Cancer Biology, Department of Pharmacogenomics, School of Pharmacy, Fourth Military Medical University, 169 West Changle Road, Xi’an, 710032, China
| | - Zhen Yan
- State Key Laboratory of Cancer Biology, Department of Pharmacogenomics, School of Pharmacy, Fourth Military Medical University, 169 West Changle Road, Xi’an, 710032, China
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231
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Fiorino S, Lorenzini S, Masetti M, Deleonardi G, Grondona AG, Silvestri T, Chili E, Del Prete P, Bacchi-Reggiani L, Cuppini A, Jovine E. Hepatitis B and C virus infections as possible risk factor for pancreatic adenocarcinoma. Med Hypotheses 2012; 79:678-97. [PMID: 22959312 DOI: 10.1016/j.mehy.2012.08.008] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2011] [Revised: 07/20/2012] [Accepted: 08/09/2012] [Indexed: 12/14/2022]
Abstract
Pancreatic adenocarcinoma (PAC) is a very aggressive and lethal cancer, with a very poor prognosis, because of absence of early symptoms, advanced stage at presentation, early metastatic dissemination and lack of both specific tests to detect its growth in the initial phases and effective systemic therapies. To date, the causes of PAC still remain largely unknown, but multiple lines of evidence from epidemiological and laboratory researches suggest that about 15-20% of all cancers are linked in some way to chronic infection, in particular it has been shown that several viruses have a role in human carcinogenesis. The purpose of this report is to discuss the hypothesis that two well-known oncogenic viruses, Human B hepatitis (HBV) and Human C hepatitis (HCV) are a possible risk factor for this cancer. Therefore, with the aim to examine the potential link between these viruses and PAC, we performed a selection of observational studies evaluating this association and we hypothesized that some pathogenetic mechanisms involved in liver carcinogenesis might be in common with pancreatic cancer development in patients with serum markers of present or past HBV and HCV infections. To date the available observational studies performed are few, heterogeneous in design as well as in end-points and with not univocal results, nevertheless they might represent the starting-point for future larger and better designed clinical trials to define this hypothesized relationship. Should these further studies confirm an association between HBV/HCV infection and PAC, screening programs might be justified in patients with active or previous hepatitis B and C viral infection.
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Affiliation(s)
- S Fiorino
- Unità Operativa di Medicina Interna, Ospedale di Budrio, Budrio, Bologna, Italy.
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232
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Characterization of nucleosome positioning in hepadnaviral covalently closed circular DNA minichromosomes. J Virol 2012; 86:10059-69. [PMID: 22787202 DOI: 10.1128/jvi.00535-12] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Hepadnaviral covalently closed circular DNA (cccDNA) exists as an episomal minichromosome in the nucleus of virus-infected hepatocytes, and serves as the transcriptional template for the synthesis of viral mRNAs. To obtain insight on the structure of hepadnaviral cccDNA minichromosomes, we utilized ducks infected with the duck hepatitis B virus (DHBV) as a model and determined the in vivo nucleosome distribution pattern on viral cccDNA by the micrococcal nuclease (MNase) mapping and genome-wide PCR amplification of isolated mononucleosomal DHBV DNA. Several nucleosome-protected sites in a region of the DHBV genome [nucleotides (nt) 2000 to 2700], known to harbor various cis transcription regulatory elements, were consistently identified in all DHBV-positive liver samples. In addition, we observed other nucleosome protection sites in DHBV minichromosomes that may vary among individual ducks, but the pattern of MNase mapping in those regions is transmittable from the adult ducks to the newly infected ducklings. These results imply that the nucleosomes along viral cccDNA in the minichromosomes are not random but sequence-specifically positioned. Furthermore, we showed in ducklings that a significant portion of cccDNA possesses a few negative superhelical turns, suggesting the presence of intermediates of viral minichromosomes assembled in the liver, where dynamic hepatocyte growth and cccDNA formation occur. This study supplies the initial framework for the understanding of the overall complete structure of hepadnaviral cccDNA minichromosomes.
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233
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Fallot G, Neuveut C, Buendia MA. Diverse roles of hepatitis B virus in liver cancer. Curr Opin Virol 2012; 2:467-73. [PMID: 22722078 DOI: 10.1016/j.coviro.2012.05.008] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2012] [Revised: 05/22/2012] [Accepted: 05/25/2012] [Indexed: 12/19/2022]
Abstract
Hepatitis B virus (HBV) is a widespread human pathogen responsible for acute and chronic liver diseases. The hepatitis B burden is particularly heavy in endemic countries, where liver cirrhosis and hepatocellular carcinoma are leading causes of death. However, the oncogenic role of HBV remains enigmatic. As the virus has no cytopathic effect, liver damage is attributed to immune responses that induce inflammation, apoptosis and regeneration, fostering the accumulation of genetic and epigenetic alterations. In a more direct action, frequent integration of HBV DNA into host chromosomes may lead to insertional mutagenesis of cancer-related genes and chromosomal instability. HBV proteins, notably the HBx transactivator, participate as co-factors in oncogenesis. Better understanding of hepatitis B pathogenesis is mandatory for improving disease management.
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234
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Dhason MS, Wang JCY, Hagan MF, Zlotnick A. Differential assembly of Hepatitis B Virus core protein on single- and double-stranded nucleic acid suggest the dsDNA-filled core is spring-loaded. Virology 2012; 430:20-9. [PMID: 22595445 DOI: 10.1016/j.virol.2012.04.012] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2011] [Revised: 02/08/2012] [Accepted: 04/19/2012] [Indexed: 02/07/2023]
Abstract
Hepatitis B Virus (HBV) cores assemble on viral RNA, which is reverse transcribed within the core to the partially dsDNA genome of mature HBV. However, constraining dsDNA, a stiff polymer, within a core necessarily requires far greater capsid stability than constraining ssRNA. We hypothesized that, unlike ssRNA, dsDNA would be a poor substrate for assembly. We examined titrations of ssDNA and dsDNA with purified HBV core protein, Cp183, by EMSA, EM, DLS, and etheno-DNA fluorescence. Cp183 bound ssDNA with high affinity to form virus-like capsids. However, Cp183 bound dsDNA poorly, forming a mixture of irregular complexes. Nonetheless, we observed some normal cores in dsDNA assembly reactions, indicating that the energy required to bend DNA could be similar to the protein-protein association energy. This similarity of energies suggests that dsDNA stresses mature HBV cores, in agreement with calculation, which may be the basis for the virus maturation signal and DNA release.
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Affiliation(s)
- Mary S Dhason
- Department of Molecular and Cellular Biochemistry, Indiana University, Bloomington, IN 47405, USA
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235
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Lucifora J, Arzberger S, Durantel D, Belloni L, Strubin M, Levrero M, Zoulim F, Hantz O, Protzer U. Hepatitis B virus X protein is essential to initiate and maintain virus replication after infection. J Hepatol 2011; 55:996-1003. [PMID: 21376091 DOI: 10.1016/j.jhep.2011.02.015] [Citation(s) in RCA: 327] [Impact Index Per Article: 25.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/08/2010] [Revised: 02/01/2011] [Accepted: 02/03/2011] [Indexed: 02/07/2023]
Abstract
BACKGROUND & AIMS The molecular biology of hepatitis B virus (HBV) has been extensively studied but the exact role of the hepatitis B X protein (HBx) in the context of natural HBV infections remains unknown. METHODS Primary human hepatocytes and differentiated HepaRG cells allowing conditional trans complementation of HBx were infected with wild type (HBV(wt)) or HBx deficient (HBV(x-)) HBV particles and establishment of HBV replication was followed. RESULTS We observed that cells inoculated with HBx-deficient HBV particles (HBV(x-)) did not lead to productive HBV infection contrary to cells inoculated with wild type HBV particles (HBV(wt)). Although equal amounts of nuclear covalently closed circular HBV-DNA (cccDNA) demonstrated comparable uptake and nuclear import, active transcription was only observed from HBV(wt) genomes. Trans-complementation of HBx was able to rescue transcription from the HBV(x-) genome and led to antigen and virion secretion, even weeks after infection. Constant expression of HBx was necessary to maintain HBV antigen expression and replication. Finally, we demonstrated that HBx is not packaged into virions during assembly but is expressed after infection within the new host cell to allow epigenetic control of HBV transcription from cccDNA. CONCLUSIONS Our results demonstrate that HBx is required to initiate and maintain HBV replication and highlight HBx as the key regulator during the natural infection process.
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Affiliation(s)
- Julie Lucifora
- Institute of Virology, Technische Universität München/Helmholtz Zentrum München, Trogerstrasse, 30, 81675 Munich, Germany
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236
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Bremer CM, Saniewski M, Wend UC, Torres P, Lelie N, Gerlich WH, Glebe D. Transient occult hepatitis B virus infection in a blood donor with high viremia. Transfusion 2011; 49:1621-9. [PMID: 19413737 DOI: 10.1111/j.1537-2995.2009.02188.x] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
BACKGROUND Screening of blood donors for viral nucleic acids has recently been introduced in several countries. With the use of transcription-mediated amplification, a blood donor was detected who had 90,000 copies of hepatitis B virus (HBV) DNA/mL but no hepatitis B surface antigen (HBsAg) or antibody to hepatitis B core antigen (anti-HBc). One month later, anti-HBc and hepatitis B surface antibody (anti-HBs) appeared; HBV DNA disappeared after 2 months. This study asked why HBsAg was undetectable in this rare case of transient occult HBV infection. STUDY DESIGN AND METHODS The HBV DNA in the first sample was cloned and sequenced to identify mutations. The physical nature of the virus was examined by polyethylene glycol precipitation, DNase digestion, density gradient centrifugation, and immunoprecipitation. RESULTS Several mutations were found all over the genome, but the HBs antigen loop was unchanged. A stop mutation in the precore region led to loss of hepatitis B e antigen (HBeAg) expression. No HBV DNA–containing immune complexes were present. The plasma did not contain nonencapsidated HBV DNA that could explain the absence of HBsAg. The virus was immune precipitated by antibodies against HBsAg or preS1 antigen. The ratio of HBV to HBsAg subviral particles was estimated to be 1 in less than 20 whereas in overt cases the ratio is 1 in more than 1000. CONCLUSION The acute resolving occult HBV infection was caused by an HBeAg-negative variant, which otherwise was almost normal. The negative HBsAg result was probably due to an unusually low production of surplus HBsAg. The absence of the viral immunomodulator HBeAg and the early appearance of anti-HBs suggested a rapid noncytolytic HBsAg-specific T-cell response leading to low expression of HBsAg.
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Affiliation(s)
- Corinna M Bremer
- Institute of Medical Virology, Justus Liebig University, Giessen, Germany
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237
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Fuente RADL, Gutiérrez ML, Garcia-Samaniego J, Fernández-Rodriguez C, Lledó JL, Castellano G. Pathogenesis of occult chronic hepatitis B virus infection. World J Gastroenterol 2011; 17:1543-8. [PMID: 21472118 PMCID: PMC3070123 DOI: 10.3748/wjg.v17.i12.1543] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/06/2010] [Revised: 01/22/2011] [Accepted: 01/29/2011] [Indexed: 02/06/2023] Open
Abstract
Occult hepatitis B infection (OBI) is characterized by hepatitis B virus (HBV) DNA in serum in the absence of hepatitis B surface antigen (HBsAg) presenting HBsAg-negative and anti-HBc positive serological patterns. Occult HBV status is associated in some cases with mutant viruses undetectable by HBsAg assays; but more frequently it is due to a strong suppression of viral replication and gene expression. OBI is an entity with world-wide diffusion. The failure to detect HBsAg, despite the persistence of the viral DNA, is due in most cases to the strong suppression of viral replication and gene expression that characterizes this “occult” HBV infection; although the mechanisms responsible for suppression of HBV are not well understood. The majority of OBI cases are secondary to overt HBV infection and represent a residual low viremia level suppressed by a strong immune response together with histological derangements which occurred during acute or chronic HBV infection. Much evidence suggests that it can favour the progression of liver fibrosis and the development of hepatocellular carcinoma.
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238
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André P, Ramière C, Scholtes C, Curtil C, Lotteau V. Role of nuclear receptors in hepatitis B and C infections. Clin Res Hepatol Gastroenterol 2011; 35:169-75. [PMID: 21316326 DOI: 10.1016/j.clinre.2011.01.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/21/2010] [Revised: 12/26/2010] [Accepted: 01/03/2011] [Indexed: 02/04/2023]
Abstract
Nuclear receptors are key regulators of many cellular functions including energy supply by the direct control of the expression of target genes. They constitute a super-family of transcription factors activated by ligands, hormones or metabolites, and therefore, sensible to host metabolic stimuli. Viral replication and production requires energy and elementary building blocks from the infected cells. Hepatitis B and C virus replication is modulated in part by liver nuclear receptors that regulate the glucose and lipid metabolism. However, nuclear receptors control the two viruses' replication by different mechanisms. The expression of hepatitis B virus genes is directly under the control of nuclear receptors, which bind to the viral genome regulatory regions. Viral replication and production may, therefore, be optimal when cells receive the correct metabolic signals. Hepatitis C virus replication and production depend to a large extent on lipidogenesis and lipoprotein secretion. The role of nuclear receptors in controlling hepatitis C replication may be to turn on the cellular mode that would provide the appropriate metabolic environment for viral replication.
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Affiliation(s)
- Patrice André
- INSERM U851, IFR 128 biosciences Lyon Gerland, université de Lyon 1, 21 avenue Tony-Garnier, Lyon, France.
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239
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Abstract
HBV has evolved a unique life cycle that results in the production of enormous viral loads during active replication without actually killing the infected cells directly. Two of the key events in the viral life cycle of HBV involve firstly the generation of a covalently closed circular (ccc)DNA transcriptional template, either from input genomic DNA or newly replicated capsid-associated DNA, and secondly, reverse transcription of the viral pregenomic (pg)RNA to form progeny HBV DNA genomes. New data are emerging regarding the epigenetic control of cccDNA, which might represent another key factor involved in the pathogenesis and natural history of the disease. Because HBV uses reverse transcription to copy its genome, mutant viral genomes emerge frequently. Particular selection pressures, both endogenous (host immune clearance) and exogenous (vaccines and antiviral drugs), readily select out these escape mutants. The particular viral mutations or combination of mutations that directly affect the clinical outcome of infection are not known; however, four major 'pathways' of antiviral drug resistance-associated substitutions have now been identified. Further studies are clearly needed to identify the pathogenetic basis and clinical sequelae arising from the selection of these particular mutants. In the clinical context of antiviral drug resistance, treating physicians need to adopt therapeutic strategies that effectively control viral replication. Finally, the role of host genetics in influencing the outcome of HBV disease in the context of natural history and therapy is beginning to aid understanding in pathogenesis and, when this knowledge is linked to pathogen-specific databases, this should translate into more individualized patient care.
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Affiliation(s)
- Stephen Locarnini
- Victorian Infectious Diseases Reference Laboratory, North Melbourne, Victoria, Australia.
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240
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Gong Q, Chen S, Guo J, Sun H, Zheng G, Liu Q, Ren H, He S. Chromosome remodeling related to hepatitis B virus replication in HepG2 cells. DNA Cell Biol 2011; 30:347-54. [PMID: 21345131 DOI: 10.1089/dna.2010.1172] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Hepatitis B Virus (HBV) covalently closed circular DNA (cccDNA) is the main replicative intermediate of HBV and is organized into minichromosomes by the interaction with histone and nonhistone proteins. The remodeling of HBV minichromosomes such as post-translational modifications of histone proteins plays an important role in regulating HBV replication. To determine whether other remodeling occurs in addition to acetylation of cccDNA-bound H3 histones in the presence of HBV replication, a cell culture replication model of HBV was used to assess the dynamic status of acetylation, phosphorylation, and methylation of cccDNA-bound H3 histones at various times after transient transfection of linear HBV DNA into human hepatoma, HepG2 cells. H3 histones bound to cccDNA were found to be phosphorylated, mono-methylated, and acetylated in HepG2 cells containing replicating HBV. The acetylation and methylation status of H3 histones bound to cccDNA paralleled HBV replication. Our results demonstrate that phosphorylation and methylation occur in the remodeling of HBV minichromosomes during HBV replication. The modifications of cccDNA-bound H3 histones were associated with the level of HBV replication. These findings suggest that alterations in the extent of minichromosome remodeling might be a potential target to inhibit HBV replication in the development of effective novel antiviral agents.
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Affiliation(s)
- Qian Gong
- Department of Gastroenterology, The 2nd Affiliated Hospital of Chongqing Medical University, No. 74 Linjiang Road, Chongqing, China
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241
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Kim JW, Lee SH, Park YS, Hwang JH, Jeong SH, Kim N, Lee DH. Replicative activity of hepatitis B virus is negatively associated with methylation of covalently closed circular DNA in advanced hepatitis B virus infection. Intervirology 2011; 54:316-25. [PMID: 21242658 DOI: 10.1159/000321450] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2010] [Accepted: 09/20/2010] [Indexed: 12/12/2022] Open
Abstract
OBJECTIVES The aim of this study was to examine the methylation status of intrahepatic hepatitis B virus (HBV) covalently closed circular DNA (cccDNA) and to elucidate the possible relationship between the cccDNA methylation and viral replicative activity in patients with HBV-related liver cirrhosis (HBV-LC). METHODS The methylation status of HBV cccDNA was investigated by bisulfite sequencing in nonneoplastic tissues from 12 patients with HBV-LC who underwent surgical resection for combined hepatocellular carcinoma. Clinical, biochemical and virologic factors were evaluated with respect to the degrees of cccDNA methylation. We also examined the effect of methylation of cccDNA on viral transcription by an in vitro transcription assay. RESULTS Variable degrees of CpG methylation were present in the HBV cccDNA from patients with HBV-LC. Old age, low serum HBV DNA levels and low virion productivity were significantly associated with elevated cccDNA methylation. Virion productivity of cccDNA was also lower in HepAD38 cells with a higher degree of cccDNA methylation. In vitro transcription assays showed that the transcriptional activity of HBV cccDNA was suppressed by increased methylation of cccDNA. CONCLUSIONS Increased CpG methylation of cccDNA is associated with old age, low serum HBV DNA levels and suppressed replicative activity in HBV-LC.
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Affiliation(s)
- Jin-Wook Kim
- Department of Medicine, Seoul National University Bundang Hospital, Seongnam, South
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242
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Gong Q, He S. Advances in understanding the biological roles of HBx. Shijie Huaren Xiaohua Zazhi 2010; 18:3656-3661. [DOI: 10.11569/wcjd.v18.i34.3656] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Hepatitis B virus (HBV) is the leading cause of liver cancer. Globally, there are over 350 million individuals chronically infected with HBV, and approximately 25% of these individuals will develop hepatocellular carcinoma (HCC). HBV is the prototype virus of the hepadnavirus family. The genome of HBV is circular and contains four open reading frames (ORFs). The HBx protein encoded by the X region of HBV is a multifunctional regulatory protein that possesses a wide transactivation activity and plays critical roles in regulating intracellular signal transduction, viral replication and transcription, cell proliferation and apoptosis, protein degradation, and heredity stability of hepatocytes. Due to its important roles in the development of chronic liver diseases, the research on the HBx protein has become a hot topic in recent years. In this paper, we will summarize the latest advances in understanding the biological roles of the HBx protein.
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243
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Nuclear HBx binds the HBV minichromosome and modifies the epigenetic regulation of cccDNA function. Proc Natl Acad Sci U S A 2009; 106:19975-9. [PMID: 19906987 DOI: 10.1073/pnas.0908365106] [Citation(s) in RCA: 367] [Impact Index Per Article: 24.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
HBV cccDNA, the template for transcription of all viral mRNAs, accumulates in the nucleus of infected cells as a stable episome organized into minichromosomes by histones and non-histone viral and cellular proteins. Using a cccDNA-specific chromatin immunoprecipitation (ChIP)-based quantitative assay, we have previously shown that transcription of the HBV minichromosome is regulated by epigenetic changes of cccDNA-bound histones and that modulation of the acetylation status of cccDNA-bound H3/H4 histones impacts on HBV replication. We now show that the cellular histone acetyltransferases CBP, p300, and PCAF/GCN5, and the histone deacetylases HDAC1 and hSirt1 are all recruited in vivo onto the cccDNA. We also found that the HBx regulatory protein produced in HBV replicating cells is recruited onto the cccDNA minichromosome, and the kinetics of HBx recruitment on the cccDNA parallels the HBV replication. As expected, an HBV mutant that does not express HBx is impaired in its replication, and exogenously expressed HBx transcomplements the replication defects. p300 recruitment is severely impaired, and cccDNA-bound histones are rapidly hypoacetylated in cells replicating the HBx mutant, whereas the recruitment of the histone deacetylases hSirt1 and HDAC1 is increased and occurs at earlier times. Finally, HBx mutant cccDNA transcribes significantly less pgRNA. Altogether our results further support the existence of a complex network of epigenetic events that influence cccDNA function and HBV replication and identify an epigenetic mechanism (i.e., to prevent cccDNA deacetylation) by which HBx controls HBV replication.
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244
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Epigenetic activation of unintegrated HIV-1 genomes by gut-associated short chain fatty acids and its implications for HIV infection. Proc Natl Acad Sci U S A 2009; 106:18786-91. [PMID: 19843699 DOI: 10.1073/pnas.0905859106] [Citation(s) in RCA: 75] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Integration of HIV-1 linear DNA into the host chromatin is an essential step in the viral life cycle. However, the majority of reverse-transcribed, nuclear-imported viral genomes remain episomal, either as linear or circular DNA. To date, these nonintegrated viral genomes are largely considered "dead-end products" of reverse transcription. Indeed, limited gene expression from nonintegrated HIV-1 has been reported, although the mechanism that renders nonintegrating HIV-1 genomes incapable of supporting efficient viral replication has not been fully elucidated. Here, we demonstrate that nonintegrating HIV-1 and HIV-1-based vector genomes are organized into chromatin structures and enriched with histone modifications typical of transcriptionally silenced chromatin. Gene expression and replication of nonintegrating HIV-1 was notably increased in vitro upon exposure to histone deacetylase inhibitors (HDACi) in the form of various short-chain fatty acids (SCFAs) known to be endogenously produced by normal microbial-gut flora. Furthermore, we demonstrated genetic and functional crosstalk between episomal and integrated vector/viral genomes, resulting in recombination between integrated and nonintegrated HIV-1, as well as mobilization of episomal vector genomes by productive viral particles encoded by integrated viral genomes. Finally, we propose a mechanism describing the role of episomal HIV-1 forms in the viral life cycle in a SCFA-rich gut environment.
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Levrero M, Pollicino T, Petersen J, Belloni L, Raimondo G, Dandri M. Control of cccDNA function in hepatitis B virus infection. J Hepatol 2009; 51:581-92. [PMID: 19616338 DOI: 10.1016/j.jhep.2009.05.022] [Citation(s) in RCA: 404] [Impact Index Per Article: 26.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
The template of hepatitis B virus (HBV) transcription, the covalently closed circular DNA (cccDNA), plays a key role in the life cycle of the virus and permits the persistence of infection. Novel molecular techniques have opened new possibilities to investigate the organization and the activity of the cccDNA minichromosome in vivo, and recent advances have started to shed light on the complexity of the mechanisms controlling cccDNA function. Nuclear cccDNA accumulates in hepatocyte nuclei as a stable minichromosome organized by histone and non-histone viral and cellular proteins. Identification of the molecular mechanisms regulating cccDNA stability and its transcriptional activity at the RNA, DNA and epigenetic levels in the course of chronic hepatitis B (CH-B) infection may reveal new potential therapeutic targets for anti-HBV drugs and hence assist in the design of strategies aimed at silencing and eventually depleting the cccDNA reservoir.
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Affiliation(s)
- Massimo Levrero
- Department of Internal Medicine, Sapienza University of Rome, Policlinico Umberto I, 0061 Rome, Italy.
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246
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Vivekanandan P, Thomas D, Torbenson M. Methylation regulates hepatitis B viral protein expression. J Infect Dis 2009; 199:1286-91. [PMID: 19301974 DOI: 10.1086/597614] [Citation(s) in RCA: 80] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
BACKGROUND Hepatitis B virus (HBV) DNA has been shown to contain CpG islands that are methylated in human tissue, which suggests a role for methylation in regulating viral protein production. However, data are lacking about whether methylation regulates viral gene expression. METHODS To investigate the hypothesis that methylation of viral DNA regulates viral gene expression, unmethylated, partially methylated, and fully methylated viral DNA was transfected into HepG2 cells. In addition, a new assay was designed that specifically identifies methylated covalently closed circular DNA (cccDNA) in human liver tissue. RESULTS Transfection of methylated HBV DNA led to reduced HBV mRNA levels in HepG2 cells, decreased surface and core protein expression in these cells, and decreased secretion of HBV viral proteins into the cell supernatant. These data provide direct evidence that CpG islands regulate gene transcription of HBV. Furthermore, methylated cccDNA was found in tumor and nonneoplastic human liver tissues. Finally, an in vitro equivalent of cccDNA showed decreased viral protein production in HepG2 cells after DNA methylation. CONCLUSION Taken together, these data demonstrate that methylation of viral CpG islands can regulate viral protein production.
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Affiliation(s)
- Perumal Vivekanandan
- Department of Pathology, the Johns Hopkins University School of Medicine, Baltimore, MD 21231, USA
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248
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Lucifora J, Durantel D, Belloni L, Barraud L, Villet S, Vincent IE, Margeridon-Thermet S, Hantz O, Kay A, Levrero M, Zoulim F. Initiation of hepatitis B virus genome replication and production of infectious virus following delivery in HepG2 cells by novel recombinant baculovirus vector. J Gen Virol 2008; 89:1819-1828. [PMID: 18632952 DOI: 10.1099/vir.0.83659-0] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
One of the major problems in gaining further insight into hepatitis B virus (HBV)/host-cell interactions is to improve the existing cellular models for the study of HBV replication. The first objective of this study was to improve the system based on transduction of HepG2 cells with a recombinant baculovirus to study HBV replication. A new HBV recombinant baculovirus, Bac-HBV-1.1, in which the synthesis of pre-genomic RNA is driven by a strong mammalian promoter, was generated. Transduction with this new recombinant baculovirus led to higher levels of HBV replication in HepG2 cells compared with levels obtained with previously described baculovirus vectors. The initiation of a complete HBV DNA replication cycle in Bac-HBV-1.1-transduced HepG2 cells was shown by the presence of HBV replicative intermediates, including covalently closed circular DNA (cccDNA). Only low levels of cccDNA were detected in the nucleus of infected cells. Data showed that cccDNA resulted from the recycling of newly synthesized nucleocapsids and was bound to acetylated histones in a chromatin-like structure. HBV particles released into the supernatant of transduced HepG2 cells were infectious in differentiated HepaRG cells. Several Bac-HBV-1.1 baculoviruses containing HBV strains carrying mutations conferring resistance to lamivudine and/or adefovir were constructed. Phenotypic analysis of these mutants confirmed the results obtained with the transfection procedures. In conclusion, an improved cell-culture system was established for the transduction of replication-competent HBV genomes. This will be useful for future studies of the fitness of HBV mutants.
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Affiliation(s)
- J Lucifora
- Université Lyon 1, IFR62 Lyon Est, 69008 Lyon, France.,INSERM, U871, 151 Cours Albert Thomas, 69003 Lyon, France
| | - D Durantel
- Hospices Civils de Lyon, Hôtel Dieu Hospital, 69002 Lyon, France.,Université Lyon 1, IFR62 Lyon Est, 69008 Lyon, France.,INSERM, U871, 151 Cours Albert Thomas, 69003 Lyon, France
| | - L Belloni
- Laboratoire Associé INSERM, U785, Villejuif, France.,Department of Internal Medicine and Laboratory of Gene Expression, Fondazione A. Cesalpino, University of Rome La Sapienza, Rome, Italy
| | - L Barraud
- Department of Internal Medicine and Laboratory of Gene Expression, Fondazione A. Cesalpino, University of Rome La Sapienza, Rome, Italy
| | - S Villet
- Université Lyon 1, IFR62 Lyon Est, 69008 Lyon, France.,INSERM, U871, 151 Cours Albert Thomas, 69003 Lyon, France
| | - I E Vincent
- Université Lyon 1, IFR62 Lyon Est, 69008 Lyon, France.,INSERM, U871, 151 Cours Albert Thomas, 69003 Lyon, France
| | - S Margeridon-Thermet
- Université Lyon 1, IFR62 Lyon Est, 69008 Lyon, France.,INSERM, U871, 151 Cours Albert Thomas, 69003 Lyon, France
| | - O Hantz
- Université Lyon 1, IFR62 Lyon Est, 69008 Lyon, France.,INSERM, U871, 151 Cours Albert Thomas, 69003 Lyon, France
| | - A Kay
- Université Lyon 1, IFR62 Lyon Est, 69008 Lyon, France.,INSERM, U871, 151 Cours Albert Thomas, 69003 Lyon, France
| | - M Levrero
- Eurofins-Viralliance, BioAlliance Pharma SA, Paris, France.,Laboratoire Associé INSERM, U785, Villejuif, France
| | - F Zoulim
- Hospices Civils de Lyon, Hôtel Dieu Hospital, 69002 Lyon, France.,Université Lyon 1, IFR62 Lyon Est, 69008 Lyon, France.,INSERM, U871, 151 Cours Albert Thomas, 69003 Lyon, France
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249
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Wiegand J, Wedemeyer H, Finger A, Heidrich B, Rosenau J, Michel G, Bock CT, Manns MP, Tillmann HL. A Decline in Hepatitis B virus Surface Antigen (HBsAg) Predicts Clearance, but does not Correlate with Quantitative HBeAg or HBV DNA Levels. Antivir Ther 2008. [DOI: 10.1177/135965350801300402] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Background The elimination of hepatitis B virus surface antigen (HBsAg) is the final goal of hepatitis B treatment, but is rarely achieved. As quantitative assays for HBsAg recently became available, we have investigated whether quantitative HBsAg measurements can substitute for hepatitis B virus (HBV) DNA quantification in treatment monitoring. Methods Within this study, 23 liver transplant patients and 18 heart transplant recipients were retrospectively analysed. Patients had been treated with famciclovir and/or lamivudine, in addition some had also received adefovir in cases of lamivudine resistance. Quantitative HBsAg and hepatitis B virus e antigen (HBeAg) levels were determined with the ArchitectTM assay. HBV DNA levels were determined with different assays available at given time points. Results We did not find a significant correlation between either HBsAg or HBeAg and HBV DNA levels – both in treated and untreated patients. More importantly, there was no significant concordance between an increase or decrease of HBsAg or HBeAg with HBV DNA. However, the curve and decline of quantitative HBsAg enabled prediction of eventual viral clearance. Eight patients showed a 2 log10 drop of HBsAg levels and eight patients demonstrated a reduction of HBsAg levels below 100 IU/ml; five patients fulfilled both criteria. Three of those five cleared HBsAg and became positive for antibodies against HBsAg. Conclusions Quantitative HBsAg and HBeAg cannot substitute for HBV DNA quantification during the assessment of antiviral therapy; however, the decline of HBsAg does predict eventual HBsAg clearance. A 2 log10 drop to below 100 IU/ml is associated with a high likelihood of HBsAg clearance.
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Affiliation(s)
- Johannes Wiegand
- Abteilung Gastroenterologie, Hepatologie und Endokrinologie, Medizinische Hochschule Hannover, Hannover, Germany
- Medizinische Klinik & Poliklinik II, Universität Leipzig, Leipzig, Germany
| | - Heiner Wedemeyer
- Abteilung Gastroenterologie, Hepatologie und Endokrinologie, Medizinische Hochschule Hannover, Hannover, Germany
| | - Andrea Finger
- Abteilung Gastroenterologie, Hepatologie und Endokrinologie, Medizinische Hochschule Hannover, Hannover, Germany
| | - Benjamin Heidrich
- Abteilung Gastroenterologie, Hepatologie und Endokrinologie, Medizinische Hochschule Hannover, Hannover, Germany
| | - Jens Rosenau
- Abteilung Gastroenterologie, Hepatologie und Endokrinologie, Medizinische Hochschule Hannover, Hannover, Germany
| | - Gerd Michel
- Foundation for Innovative New Diagnostics (FIND), 1216 Cointrin/Geneva, Switzerland
| | - C Thomas Bock
- Department of Molecular Pathology, Institute for Pathology, University Hospital of Tübingen, Tübingen, Germany
| | - Michael P Manns
- Abteilung Gastroenterologie, Hepatologie und Endokrinologie, Medizinische Hochschule Hannover, Hannover, Germany
- Medizinische Klinik & Poliklinik II, Universität Leipzig, Leipzig, Germany
- Duke Clinical Research Institute, Durham, NC 27705, USA
| | - Hans L Tillmann
- Abteilung Gastroenterologie, Hepatologie und Endokrinologie, Medizinische Hochschule Hannover, Hannover, Germany
- Medizinische Klinik & Poliklinik II, Universität Leipzig, Leipzig, Germany
- Duke Clinical Research Institute, Durham, NC 27705, USA
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250
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Abstract
The hepatitis B virus (HBV) belongs to the hepadnavirus family. The genome of the virus, formed by a small DNA molecule with 3,200 base pairs, has 4 strongly overlapping protein coding regions: ORF preS/S, corresponding to the envelope proteins that constitute the HBV surface antigen (HBsAg); ORF preC/C, which encodes the viral capsid component (core antigen or HBcAg) and a non-structural protein that, after postranslation modification, is secreted and constitutes the "e" antigen (HBeAg); ORF P, which encodes the viral polymerase (polyprotein with DNA polymerase activity, reverse transcriptase and RNAase), and ORF X, which encodes a protein that acts as a multifunctional regulator for both the viral and cell cycles. HBV has a mutation rate of 1.4-3.2 x 105 substitutions/nucleotide/year. As a result of this variability, the virus circulates as a complex mixture of genetic variants, constituting a semi-species, that evolves throughout the infection depending on the evolutionary pressure of factors such as the immune response and antiviral treatments. Based on this variability, HBV has been classified into 8 genotypes (A-H) defined by a difference of more than 8% in the sequences of the complete viral genome. This variability is also responsible for HBV resistance to antiviral treatments with nucleotide and nucleoside analogs. Diagnosis of HBV infection includes determination of virological markers: viral antigens (HBsAg, HBeAg), specific antibodies (anti-HBc, anti-HBe, anti-HBs) and study of HBV-DNA for its detection and quantification and determination of genotypes and viral variants.
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