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Abstract
Hepatitis B virus (HBV) infection is a major global health problem with over 240 million infected individuals at risk of developing progressive liver disease and hepatocellular carcinoma. HBV is an enveloped DNA virus that establishes its genome as an episomal, covalently closed circular DNA (cccDNA) in the nucleus of infected hepatocytes. Currently, available standard-of-care treatments for chronic hepatitis B (CHB) include nucleos(t)ide analogues (NAs) that suppress HBV replication but do not target the cccDNA and hence rarely cure infection. There is considerable interest in determining the lifespan of cccDNA molecules to design and evaluate new curative treatments. We took a novel approach to this problem by developing a new mathematical framework to model changes in evolutionary rates during infection which, combined with previously determined within-host evolutionary rates of HBV, we used to determine the lifespan of cccDNA. We estimate that during HBe-antigen positive (HBeAgPOS) infection the cccDNA lifespan is 61 (36-236) days, whereas during the HBeAgNEG phase of infection it is only 26 (16-81) days. We found that cccDNA replicative capacity declined by an order of magnitude between HBeAgPOS and HBeAgNEG phases of infection. Our estimated lifespan of cccDNA is too short to explain the long durations of chronic infection observed in patients on NA treatment, suggesting that either a sub-population of long-lived hepatocytes harbouring cccDNA molecules persists during therapy, or that NA therapy does not suppress all viral replication. These results provide a greater understanding of the biology of the cccDNA reservoir and can aid the development of new curative therapeutic strategies for treating CHB.
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Affiliation(s)
- Katrina A Lythgoe
- Big Data Institute, University of Oxford, Old Road Campus, Oxford OX3 7LF, UK
- Department of Zoology, University of Oxford, Medawar Building, South Parks Road, Oxford OX1 3SY, UK
| | - Sheila F Lumley
- Nuffield Department of Medicine, University of Oxford, Medawar Building, South Parks Road, Oxford OX1 3SY, UK
- Department of Infectious Diseases and Microbiology, Oxford University Hospitals NHS Foundation Trust, John Radcliffe Hospital, Headley Way, Oxford OX3 9DU, UK
| | - Lorenzo Pellis
- Department of Mathematics, Alan Turing Building, Oxford Rd, Manchester M13 9PL, UK
| | - Jane A McKeating
- Nuffield Department of Medicine Research Building, University of Oxford, Oxford OX3 7LF, UK
| | - Philippa C Matthews
- Nuffield Department of Medicine, University of Oxford, Medawar Building, South Parks Road, Oxford OX1 3SY, UK
- Department of Infectious Diseases and Microbiology, Oxford University Hospitals NHS Foundation Trust, John Radcliffe Hospital, Headley Way, Oxford OX3 9DU, UK
- NIHR Biomedical Research Centre, John Radcliffe Hospital, Headley Way, Oxford OX3 9DU, UK
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Wing PA, Davenne T, Wettengel J, Lai AG, Zhuang X, Chakraborty A, D'Arienzo V, Kramer C, Ko C, Harris JM, Schreiner S, Higgs M, Roessler S, Parish JL, Protzer U, Balfe P, Rehwinkel J, McKeating JA. A dual role for SAMHD1 in regulating HBV cccDNA and RT-dependent particle genesis. Life Sci Alliance 2019; 2:e201900355. [PMID: 30918010 PMCID: PMC6438393 DOI: 10.26508/lsa.201900355] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2019] [Revised: 03/15/2019] [Accepted: 03/18/2019] [Indexed: 02/06/2023] Open
Abstract
Chronic hepatitis B is one of the world's unconquered diseases with more than 240 million infected subjects at risk of developing liver disease and hepatocellular carcinoma. Hepatitis B virus reverse transcribes pre-genomic RNA to relaxed circular DNA (rcDNA) that comprises the infectious particle. To establish infection of a naïve target cell, the newly imported rcDNA is repaired by host enzymes to generate covalently closed circular DNA (cccDNA), which forms the transcriptional template for viral replication. SAMHD1 is a component of the innate immune system that regulates deoxyribonucleoside triphosphate levels required for host and viral DNA synthesis. Here, we show a positive role for SAMHD1 in regulating cccDNA formation, where KO of SAMHD1 significantly reduces cccDNA levels that was reversed by expressing wild-type but not a mutated SAMHD1 lacking the nuclear localization signal. The limited pool of cccDNA in infected Samhd1 KO cells is transcriptionally active, and we observed a 10-fold increase in newly synthesized rcDNA-containing particles, demonstrating a dual role for SAMHD1 to both facilitate cccDNA genesis and to restrict reverse transcriptase-dependent particle genesis.
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Affiliation(s)
- Peter Ac Wing
- Nuffield Department of Medicine, University of Oxford, Oxford, UK
| | - Tamara Davenne
- Medical Research Council Human Immunology Unit, Medical Research Council Weatherall Institute of Molecular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, UK
| | - Jochen Wettengel
- Institute of Virology, Technische Universität München/Helmholtz Zentrum München, Munich, Germany
| | - Alvina G Lai
- Nuffield Department of Medicine, University of Oxford, Oxford, UK
| | - Xiaodong Zhuang
- Nuffield Department of Medicine, University of Oxford, Oxford, UK
| | - Anindita Chakraborty
- Institute of Virology, Technische Universität München/Helmholtz Zentrum München, Munich, Germany
| | | | - Catharina Kramer
- Nuffield Department of Medicine, University of Oxford, Oxford, UK
| | - Chunkyu Ko
- Institute of Virology, Technische Universität München/Helmholtz Zentrum München, Munich, Germany
| | - James M Harris
- Nuffield Department of Medicine, University of Oxford, Oxford, UK
| | - Sabrina Schreiner
- Institute of Virology, Technische Universität München/Helmholtz Zentrum München, Munich, Germany
- German Center for Infection Research (DZIF), Munich Partner Site, Munich, Germany
| | - Martin Higgs
- Institutes of Cancer and Genomic Sciences and Immunity and Immunotherapy, College of Medical and Dental Sciences, University of Birmingham, UK
| | - Stephanie Roessler
- Institute of Pathology, University Hospital Heidelberg, Heidelberg, Germany
| | - Joanna L Parish
- Institutes of Cancer and Genomic Sciences and Immunity and Immunotherapy, College of Medical and Dental Sciences, University of Birmingham, UK
| | - Ulrike Protzer
- Institute of Virology, Technische Universität München/Helmholtz Zentrum München, Munich, Germany
- German Center for Infection Research (DZIF), Munich Partner Site, Munich, Germany
| | - Peter Balfe
- Institutes of Cancer and Genomic Sciences and Immunity and Immunotherapy, College of Medical and Dental Sciences, University of Birmingham, UK
| | - Jan Rehwinkel
- Medical Research Council Human Immunology Unit, Medical Research Council Weatherall Institute of Molecular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, UK
| | - Jane A McKeating
- Nuffield Department of Medicine, University of Oxford, Oxford, UK
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