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McCoullough LC, Sadauskas T, Sozzi V, Mak KY, Mason H, Littlejohn M, Revill PA. The in vitro replication phenotype of hepatitis B virus (HBV) splice variants Sp3 and Sp9 and their impact on wild-type HBV replication. J Virol 2024; 98:e0153823. [PMID: 38501924 PMCID: PMC11019940 DOI: 10.1128/jvi.01538-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2023] [Accepted: 02/22/2024] [Indexed: 03/20/2024] Open
Abstract
Prior to nuclear export, the hepatitis B virus (HBV) pregenomic RNA may be spliced by the host cell spliceosome to form shorter RNA sequences known as splice variants. Due to deletions in the open reading frames, splice variants may encode novel fusion proteins. Although not essential for HBV replication, the role of splice variants and their novel fusion proteins largely remains unknown. Some splice variants and their encoded novel fusion proteins have been shown to impair or promote wild-type HBV replication in vitro, and although splice variants Sp3 and Sp9 are two of the most common splice variants identified to date, their in vitro replication phenotype and their impact on wild-type HBV replication are unclear. Here, we utilize greater than genome-length Sp3 and Sp9 constructs to investigate their replication phenotype in vitro, and their impact on wild-type HBV replication. We show that Sp3 and Sp9 were incapable of autonomous replication, which was rescued by providing the polymerase and core proteins in trans. Furthermore, we showed that Sp3 had no impact on wild-type HBV replication, whereas Sp9 strongly reduced wild-type HBV replication in co-transfection experiments. Knocking out Sp9 novel precore-surface and core-surface fusion protein partially restored replication, suggesting that these proteins contributed to suppression of wild-type HBV replication, providing further insights into factors regulating HBV replication in vitro. IMPORTANCE The role of hepatitis B virus (HBV) splice variants in HBV replication and pathogenesis currently remains largely unknown. However, HBV splice variants have been associated with the development of hepatocellular carcinoma, suggesting a role in HBV pathogenesis. Several in vitro co-transfection studies have shown that different splice variants have varying impacts on wild-type HBV replication, perhaps contributing to viral persistence. Furthermore, all splice variants are predicted to produce novel fusion proteins. Sp1 hepatitis B splice protein contributes to liver disease progression and apoptosis; however, the function of other HBV splice variant novel fusion proteins remains largely unknown. We show that Sp9 markedly impairs HBV replication in a cell culture co-transfection model, mediated by expression of Sp9 novel fusion proteins. In contrast, Sp3 had no effect on wild-type HBV replication. Together, these studies provide further insights into viral factors contributing to regulation of HBV replication.
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Affiliation(s)
- Laura C. McCoullough
- Victorian Infectious Diseases Reference Laboratory, Royal Melbourne Hospital at the Peter Doherty Institute for Infection and Immunity, Melbourne, Australia
- Department of Microbiology and Immunology, University of Melbourne at the Peter Doherty Institute for Infection and Immunity, Melbourne, Australia
| | - Tomas Sadauskas
- Victorian Infectious Diseases Reference Laboratory, Royal Melbourne Hospital at the Peter Doherty Institute for Infection and Immunity, Melbourne, Australia
- Department of Microbiology and Immunology, University of Melbourne at the Peter Doherty Institute for Infection and Immunity, Melbourne, Australia
| | - Vitina Sozzi
- Victorian Infectious Diseases Reference Laboratory, Royal Melbourne Hospital at the Peter Doherty Institute for Infection and Immunity, Melbourne, Australia
| | - Kai Yan Mak
- Victorian Infectious Diseases Reference Laboratory, Royal Melbourne Hospital at the Peter Doherty Institute for Infection and Immunity, Melbourne, Australia
| | - Hugh Mason
- Victorian Infectious Diseases Reference Laboratory, Royal Melbourne Hospital at the Peter Doherty Institute for Infection and Immunity, Melbourne, Australia
| | - Margaret Littlejohn
- Victorian Infectious Diseases Reference Laboratory, Royal Melbourne Hospital at the Peter Doherty Institute for Infection and Immunity, Melbourne, Australia
- Department of Infectious Diseases, University of Melbourne at the Peter Doherty Institute for Infection and Immunity, Melbourne, Australia
| | - Peter A. Revill
- Victorian Infectious Diseases Reference Laboratory, Royal Melbourne Hospital at the Peter Doherty Institute for Infection and Immunity, Melbourne, Australia
- Department of Infectious Diseases, University of Melbourne at the Peter Doherty Institute for Infection and Immunity, Melbourne, Australia
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2
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Xu X, Zhang L, Ye G, Shi J, Peng Y, Xin F, Lin Y, Wu Q, Lin X, Chen W. Hepatitis B doubly spliced protein (HBDSP) promotes hepatocellular carcinoma cell apoptosis via ETS1/GATA2/YY1-mediated p53 transcription. J Virol 2023; 97:e0108723. [PMID: 37929990 PMCID: PMC10688342 DOI: 10.1128/jvi.01087-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2023] [Accepted: 09/26/2023] [Indexed: 11/07/2023] Open
Abstract
IMPORTANCE Hepatitis B virus (HBV) spliced variants are associated with viral persistence or pathogenicity. Hepatitis B doubly spliced protein (HBDSP), which has been previously reported as a pleiotropic transactivator protein, can potentially serve as an HBV virulence factor. However, the underlying mechanisms of HBDSP in HBV-associated liver diseases remain to be elucidated. In this study, we revealed that HBDSP promotes cellular apoptosis and induces wt-p53-dependent apoptotic signaling pathway in wt-p53 hepatocellular cells by transactivating p53 transcription, and increases the release of HBV progeny. Therefore, HBDSP may promote the HBV particles release through wt-p53-dependent hepatocellular apoptosis. Our findings suggest that blocking HBDSP-induced wt-p53-dependent apoptosis might have therapeutic values for chronic hepatitis B.
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Affiliation(s)
- Xiazhen Xu
- Key Laboratory of Gastrointestinal Cancer (Fujian Medical University), Ministry of Education, School of Basic Medical Sciences, Fujian Medical University, Fuzhou, China
| | - Lu Zhang
- Key Laboratory of Gastrointestinal Cancer (Fujian Medical University), Ministry of Education, School of Basic Medical Sciences, Fujian Medical University, Fuzhou, China
| | - Guiying Ye
- Key Laboratory of Gastrointestinal Cancer (Fujian Medical University), Ministry of Education, School of Basic Medical Sciences, Fujian Medical University, Fuzhou, China
| | - Jiajian Shi
- Key Laboratory of Gastrointestinal Cancer (Fujian Medical University), Ministry of Education, School of Basic Medical Sciences, Fujian Medical University, Fuzhou, China
| | - Yibin Peng
- Key Laboratory of Gastrointestinal Cancer (Fujian Medical University), Ministry of Education, School of Basic Medical Sciences, Fujian Medical University, Fuzhou, China
| | - Fan Xin
- Key Laboratory of Gastrointestinal Cancer (Fujian Medical University), Ministry of Education, School of Basic Medical Sciences, Fujian Medical University, Fuzhou, China
- Fujian Key Laboratory of Tumor Microbiology, Department of Medical Microbiology, School of Basic Medical Sciences, Fujian Medical University, Fuzhou, China
| | - Yi Lin
- Key Laboratory of Gastrointestinal Cancer (Fujian Medical University), Ministry of Education, School of Basic Medical Sciences, Fujian Medical University, Fuzhou, China
- Fujian Key Laboratory of Tumor Microbiology, Department of Medical Microbiology, School of Basic Medical Sciences, Fujian Medical University, Fuzhou, China
| | - Qiong Wu
- Key Laboratory of Gastrointestinal Cancer (Fujian Medical University), Ministry of Education, School of Basic Medical Sciences, Fujian Medical University, Fuzhou, China
- Fujian Key Laboratory of Tumor Microbiology, Department of Medical Microbiology, School of Basic Medical Sciences, Fujian Medical University, Fuzhou, China
| | - Xu Lin
- Key Laboratory of Gastrointestinal Cancer (Fujian Medical University), Ministry of Education, School of Basic Medical Sciences, Fujian Medical University, Fuzhou, China
- Fujian Key Laboratory of Tumor Microbiology, Department of Medical Microbiology, School of Basic Medical Sciences, Fujian Medical University, Fuzhou, China
| | - Wannan Chen
- Key Laboratory of Gastrointestinal Cancer (Fujian Medical University), Ministry of Education, School of Basic Medical Sciences, Fujian Medical University, Fuzhou, China
- Fujian Key Laboratory of Tumor Microbiology, Department of Medical Microbiology, School of Basic Medical Sciences, Fujian Medical University, Fuzhou, China
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3
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Zhao L, Lythgoe KA. The social role of defective viral genomes in chronic viral infections: a commentary on Leeks et al. 2023. J Evol Biol 2023; 36:1577-1581. [PMID: 37975505 PMCID: PMC10880559 DOI: 10.1111/jeb.14244] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2023] [Accepted: 10/05/2023] [Indexed: 11/19/2023]
Affiliation(s)
- Lele Zhao
- Big Data Institute, Li Ka Shing Centre for Health Information and Discovery, Nuffield Department of MedicineUniversity of OxfordOxfordUK
- Pandemic Sciences Institute, Nuffield Department for MedicineUniversity of OxfordOxfordUK
| | - Katrina A. Lythgoe
- Big Data Institute, Li Ka Shing Centre for Health Information and Discovery, Nuffield Department of MedicineUniversity of OxfordOxfordUK
- Pandemic Sciences Institute, Nuffield Department for MedicineUniversity of OxfordOxfordUK
- Department of BiologyUniversity of OxfordOxfordUK
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4
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Villanueva RA, Loyola A. Pre- and Post-Transcriptional Control of HBV Gene Expression: The Road Traveled towards the New Paradigm of HBx, Its Isoforms, and Their Diverse Functions. Biomedicines 2023; 11:1674. [PMID: 37371770 DOI: 10.3390/biomedicines11061674] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2023] [Revised: 06/04/2023] [Accepted: 06/07/2023] [Indexed: 06/29/2023] Open
Abstract
Hepatitis B virus (HBV) is an enveloped DNA human virus belonging to the Hepadnaviridae family. Perhaps its main distinguishable characteristic is the replication of its genome through a reverse transcription process. The HBV circular genome encodes only four overlapping reading frames, encoding for the main canonical proteins named core, P, surface, and X (or HBx protein). However, pre- and post-transcriptional gene regulation diversifies the full HBV proteome into diverse isoform proteins. In line with this, hepatitis B virus X protein (HBx) is a viral multifunctional and regulatory protein of 16.5 kDa, whose canonical reading frame presents two phylogenetically conserved internal in-frame translational initiation codons, and which results as well in the expression of two divergent N-terminal smaller isoforms of 8.6 and 5.8 kDa, during translation. The canonical HBx, as well as the smaller isoform proteins, displays different roles during viral replication and subcellular localizations. In this article, we reviewed the different mechanisms of pre- and post-transcriptional regulation of protein expression that take place during viral replication. We also investigated all the past and recent evidence about HBV HBx gene regulation and its divergent N-terminal isoform proteins. Evidence has been collected for over 30 years. The accumulated evidence simply strengthens the concept of a new paradigm of the canonical HBx, and its smaller divergent N-terminal isoform proteins, not only during viral replication, but also throughout cell pathogenesis.
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Affiliation(s)
| | - Alejandra Loyola
- Centro Ciencia & Vida, Fundación Ciencia & Vida, Santiago 8580702, Chile
- Facultad de Medicina y Ciencia, Universidad San Sebastián, Santiago 7510602, Chile
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5
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Sozzi V, McCoullough L, Mason H, Littlejohn M, Revill P. The in vitro replication phenotype of hepatitis B virus (HBV) splice variant Sp1. Virology 2022; 574:65-70. [DOI: 10.1016/j.virol.2022.07.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2022] [Revised: 07/08/2022] [Accepted: 07/09/2022] [Indexed: 11/30/2022]
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6
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Maslac O, Wagner J, Sozzi V, Mason H, Svarovskaia J, Tan S, Gaggar A, Locarnini S, Yuen L, Littlejohn M, Revill PA. Secreted hepatitis B virus splice variants differ by HBV genotype and across phases of chronic hepatitis B infection. J Viral Hepat 2022; 29:604-615. [PMID: 35582878 PMCID: PMC9544302 DOI: 10.1111/jvh.13702] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/17/2022] [Revised: 04/25/2022] [Accepted: 04/27/2022] [Indexed: 12/09/2022]
Abstract
Chronic hepatitis B (CHB) is characterized by progression through different phases of hepatitis B virus (HBV) infection and disease. Although not necessary for HBV replication, there is increasing evidence that HBV splice variants are associated with liver disease progression and pathogenesis. However, there have been no studies till date on the frequency or diversity of splice variants for different HBV genotypes across the phases of CHB. Next generation sequencing data from 404 patient samples of HBV genotype A, B, C or D in Phase I, Phase II or Phase IV of CHB was analysed for HBV splice variants using an in house bioinformatics pipeline. HBV splice variants differed in frequency and type by genotype and phase of natural history. Splice variant Sp1 was the most frequently detected (206/404, 51% of patients), followed by Sp13 (151/404 37% of patients). The frequency of variants was generally highest in Phase II (123/165, 75% of patients), a phase typically associated with enhanced immune activation, followed by Phase I (69/99, 70% of patients). Splice variants were associated with reduced hepatitis B e antigen (HBeAg) levels and statistically reduced likelihood of achieving HBsAg loss (functional cure) in Phase II patients for Sp1 and Sp13 (p = .0014 and .0156, respectively). The frequency of HBV splice variants in patient serum differed markedly by HBV genotype and phase of CHB natural history. The increased levels of HBV splice variants detected in CHB phase II patients compared with the higher replicative Phase I in particular warrants further investigation.
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Affiliation(s)
- Olivia Maslac
- Division of Molecular Research and DevelopmentVictorian Infectious Diseases Reference LaboratoryPeter Doherty Institute for Infection and ImmunityRoyal Melbourne HospitalMelbourneVictoriaAustralia,Department of MicrobiologyMonash UniversityClaytonVictoriaAustralia
| | - Josef Wagner
- Division of Molecular Research and DevelopmentVictorian Infectious Diseases Reference LaboratoryPeter Doherty Institute for Infection and ImmunityRoyal Melbourne HospitalMelbourneVictoriaAustralia
| | - Vitina Sozzi
- Division of Molecular Research and DevelopmentVictorian Infectious Diseases Reference LaboratoryPeter Doherty Institute for Infection and ImmunityRoyal Melbourne HospitalMelbourneVictoriaAustralia
| | - Hugh Mason
- Division of Molecular Research and DevelopmentVictorian Infectious Diseases Reference LaboratoryPeter Doherty Institute for Infection and ImmunityRoyal Melbourne HospitalMelbourneVictoriaAustralia
| | | | | | | | - Stephen Locarnini
- Division of Molecular Research and DevelopmentVictorian Infectious Diseases Reference LaboratoryPeter Doherty Institute for Infection and ImmunityRoyal Melbourne HospitalMelbourneVictoriaAustralia
| | - Lilly Yuen
- Division of Molecular Research and DevelopmentVictorian Infectious Diseases Reference LaboratoryPeter Doherty Institute for Infection and ImmunityRoyal Melbourne HospitalMelbourneVictoriaAustralia
| | - Margaret Littlejohn
- Division of Molecular Research and DevelopmentVictorian Infectious Diseases Reference LaboratoryPeter Doherty Institute for Infection and ImmunityRoyal Melbourne HospitalMelbourneVictoriaAustralia,Department of Infectious DiseasesUniversity of MelbourneParkvilleVictoriaAustralia
| | - Peter A. Revill
- Division of Molecular Research and DevelopmentVictorian Infectious Diseases Reference LaboratoryPeter Doherty Institute for Infection and ImmunityRoyal Melbourne HospitalMelbourneVictoriaAustralia,Department of MicrobiologyMonash UniversityClaytonVictoriaAustralia,Department of Microbiology and ImmunologyUniversity of MelbourneParkvilleVictoriaAustralia
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7
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Pley C, Lourenço J, McNaughton AL, Matthews PC. Spacer Domain in Hepatitis B Virus Polymerase: Plugging a Hole or Performing a Role? J Virol 2022; 96:e0005122. [PMID: 35412348 PMCID: PMC9093120 DOI: 10.1128/jvi.00051-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2022] [Accepted: 03/14/2022] [Indexed: 11/25/2022] Open
Abstract
Hepatitis B virus (HBV) polymerase is divided into terminal protein, spacer, reverse transcriptase, and RNase domains. Spacer has previously been considered dispensable, merely acting as a tether between other domains or providing plasticity to accommodate deletions and mutations. We explore evidence for the role of spacer sequence, structure, and function in HBV evolution and lineage, consider its associations with escape from drugs, vaccines, and immune responses, and review its potential impacts on disease outcomes.
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Affiliation(s)
- Caitlin Pley
- School of Clinical Medicine, University of Cambridge, Cambridge, United Kingdom
- Guy’s and St Thomas’ NHS Foundation Trust, London, United Kingdom
| | - José Lourenço
- Department of Zoology, University of Oxford, Oxford, United Kingdom
- Biosystems and Integrative Sciences Institute, University of Lisbon, Lisbon, Portugal
| | - Anna L. McNaughton
- Population Health Science, Bristol Medical School, University of Bristol, Bristol, United Kingdom
- Nuffield Department of Medicine, University of Oxford Medawar Building, Oxford, United Kingdom
| | - Philippa C. Matthews
- Nuffield Department of Medicine, University of Oxford Medawar Building, Oxford, United Kingdom
- The Francis Crick Institute, London, United Kingdom
- Division of Infection and Immunity, University College London, London, United Kingdom
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8
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Kremsdorf D, Lekbaby B, Bablon P, Sotty J, Augustin J, Schnuriger A, Pol J, Soussan P. Alternative splicing of viral transcripts: the dark side of HBV. Gut 2021; 70:2373-2382. [PMID: 34535538 DOI: 10.1136/gutjnl-2021-324554] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/02/2021] [Accepted: 09/06/2021] [Indexed: 02/06/2023]
Abstract
Regulation of alternative splicing is one of the most efficient mechanisms to enlarge the proteomic diversity in eukaryotic organisms. Many viruses hijack the splicing machinery following infection to accomplish their replication cycle. Regarding the HBV, numerous reports have described alternative splicing events of the long viral transcript (pregenomic RNA), which also acts as a template for viral genome replication. Alternative splicing of HBV pregenomic RNAs allows the synthesis of at least 20 spliced variants. In addition, almost all these spliced forms give rise to defective particles, detected in the blood of infected patients. HBV-spliced RNAs have long been unconsidered, probably due to their uneasy detection in comparison to unspliced forms as well as for their dispensable role during viral replication. However, recent data highlighted the relevance of these HBV-spliced variants through (1) the trans-regulation of the alternative splicing of viral transcripts along the course of liver disease; (2) the ability to generate defective particle formation, putative biomarker of the liver disease progression; (3) modulation of viral replication; and (4) their intrinsic propensity to encode for novel viral proteins involved in liver pathogenesis and immune response. Altogether, tricky regulation of HBV alternative splicing may contribute to modulate multiple viral and cellular processes all along the course of HBV-related liver disease.
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Affiliation(s)
- Dina Kremsdorf
- Institut National de la Santé et de la Recherche Médicale U938, Centre de Recherche de Saint Antoine, Sorbonne Université-Faculté Saint Antoine, Paris, France
| | - Bouchra Lekbaby
- Institut National de la Santé et de la Recherche Médicale U938, Centre de Recherche de Saint Antoine, Sorbonne Université-Faculté Saint Antoine, Paris, France
| | - Pierre Bablon
- Institut National de la Santé et de la Recherche Médicale U938, Centre de Recherche de Saint Antoine, Sorbonne Université-Faculté Saint Antoine, Paris, France
| | - Jules Sotty
- Institut National de la Santé et de la Recherche Médicale U938, Centre de Recherche de Saint Antoine, Sorbonne Université-Faculté Saint Antoine, Paris, France
| | - Jérémy Augustin
- Institut National de la Santé et de la Recherche Médicale U938, Centre de Recherche de Saint Antoine, Sorbonne Université-Faculté Saint Antoine, Paris, France
| | - Aurélie Schnuriger
- Institut National de la Santé et de la Recherche Médicale U938, Centre de Recherche de Saint Antoine, Sorbonne Université-Faculté Saint Antoine, Paris, France.,Assistance Publique - Hôpitaux de Paris, Département de Virologie, GHU Paris-Est, Paris, France
| | - Jonathan Pol
- Institut National de la Santé et de la Recherche Médicale U1138, Centre de Recherche des Cordeliers, Université de Paris, Sorbonne Université, Paris, France.,Metabolomics ann Cell Biology Platforms, Gustave Roussy Cancer Campus, Villejuif, France
| | - Patrick Soussan
- Institut National de la Santé et de la Recherche Médicale U938, Centre de Recherche de Saint Antoine, Sorbonne Université-Faculté Saint Antoine, Paris, France .,Assistance Publique - Hôpitaux de Paris, Département de Virologie, GHU Paris-Est, Paris, France
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9
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Wang T, Qin Y, Zhang J, Li X, Tong S, Zhao W, Zhang J. An antiviral drug-resistant mutant of hepatitis B virus with high replication capacity in association with a large in-frame deletion in the preS1 region of viral surface gene. Virus Genes 2020; 56:677-686. [PMID: 32840739 DOI: 10.1007/s11262-020-01787-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2019] [Accepted: 08/08/2020] [Indexed: 12/14/2022]
Abstract
We amplified a full-length hepatitis B virus (HBV) genome from the serum of a chronic hepatitis B patient who experienced virological breakthrough with high HBV DNA titer following adefovir (ADV) therapy. The PCR product was cloned and sequencing of the six clones revealed an isolate of C2 subgenotype. Mutation(s) in the polymerase gene responsible for ADV resistance included rtA181T (all clones) and rtN236T (four clones). The rtA181T mutation caused the W172* nonsense mutation in the overlapping S gene. In addition, all the clones harbored another nonsense mutation in the S gene (C69*) and a 207nt in-frame deletion in the preS1 region. These clones were converted to a 1.1mer construct for transient transfection of Huh7 cells. All the clones were deficient in hepatitis B surface antigen production. Three clones had similar levels of DNA replication. Comparison with a wild-type clone of the same genotype revealed a higher intracellular level of replicative DNA for clone c4, which was reduced by putting back the deleted 207nt, but not by co-transfection with an expression construct for the three surface proteins to rescue virion production. The HBcAg expression of the c4 and c4+207nt clones was mainly in the nucleus. Co-transfection with the L/M/S proteins expression construct did not alter the distribution of core. Clone c4 showed a significantly decreased susceptibility to ADV, a mild reduction in susceptibility to lamivudine and tenofovir, but remained sensitive to entecavir. In conclusion, this is an unusual ADV-resistant HBV isolate harboring two nonsense mutations in the S gene and a large in-frame deletion in the preS1 region, but still retains a high replication phenotype, which can provide a platform for recombinant vector construction.
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Affiliation(s)
- Ting Wang
- Department of Infectious Diseases, Jing'An District Centre Hospital of Shanghai (Huashan Hospital, Fudan University Jing'An Branch), Shanghai, China.,Department of Infectious Diseases, The First Affiliated Hospital of Soochow University, 188 Shizi Street, Gusu District, Soochow, 215006, Jiangsu, China
| | - Yanli Qin
- Department of Infectious Diseases, Huashan Hospital, Fudan University, 12 Middle Wulumuqi Road, Shanghai, 200040, China
| | - Jing Zhang
- Key Lab of Medical Molecular Virology, School of Basic Medical Sciences, Fudan University, Shanghai, China
| | - Xinyan Li
- Department of Hepatitis Diseases, Shanghai Public Health Clinical Center, Fudan University, Shanghai, China
| | - Shuping Tong
- Key Lab of Medical Molecular Virology, School of Basic Medical Sciences, Fudan University, Shanghai, China
| | - Weifeng Zhao
- Department of Infectious Diseases, The First Affiliated Hospital of Soochow University, 188 Shizi Street, Gusu District, Soochow, 215006, Jiangsu, China.
| | - Jiming Zhang
- Department of Infectious Diseases, Jing'An District Centre Hospital of Shanghai (Huashan Hospital, Fudan University Jing'An Branch), Shanghai, China. .,Department of Infectious Diseases, Huashan Hospital, Fudan University, 12 Middle Wulumuqi Road, Shanghai, 200040, China.
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10
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Nakajima S, Watashi K, Fukano K, Tsukuda S, Wakae K, Aizaki H, Muramatsu M, Wakita T, Toyoda T. Non-nucleoside hepatitis B virus polymerase inhibitors identified by an in vitro polymerase elongation assay. J Gastroenterol 2020; 55:441-52. [PMID: 31768802 DOI: 10.1007/s00535-019-01643-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/30/2019] [Accepted: 11/12/2019] [Indexed: 02/04/2023]
Abstract
BACKGROUND Hepatitis B virus (HBV) polymerase is the only virus-encoded enzyme essential for producing the HBV genome and is regarded as an attractive drug target. However, the difficulty of synthesizing and purifying recombinant HBV polymerase protein has hampered the development of new drugs targeting this enzyme, especially compounds unrelated to the nucleoside structure. We recently have developed a technique for the synthesis and purification of recombinant HBV polymerase containing the reverse transcriptase (RT) domain that carried DNA elongation activity in vitro. METHODS We used the overproduced protein to establish an in vitro high-throughput screening system to identify compounds that inhibit the elongation activity of HBV polymerase. RESULTS We screened 1120 compounds and identified a stilbene derivative, piceatannol, as a potential anti-HBV agent. Derivative analysis identified another stilbene derivative, PDM2, that was able to inhibit HBV replication with an IC50 of 14.4 ± 7.7 μM. An infection experiment suggested that the compounds inhibit the replication of HBV rather than the entry process, as expected. Surface plasmon resonance analysis demonstrated a specific interaction between PDM2 and the RT domain. Importantly, PDM2 showed similar inhibitory activity against the replication of both wild-type HBV and a lamivudine/entecavir-resistant HBV variant. Furthermore, PDM2 showed an additive effect in combination with clinically used nucleos(t)ide analogs. CONCLUSIONS We report the development of a screening system that is useful for identifying non-nucleos(t)ide RT inhibitors.
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11
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Toyoda T, Wang Y, Wen Y, Tanaka Y. Fluorescence-based biochemical analysis of human hepatitis B virus reverse transcriptase activity. Anal Biochem 2020; 597:113642. [PMID: 32171777 DOI: 10.1016/j.ab.2020.113642] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2019] [Revised: 02/04/2020] [Accepted: 02/18/2020] [Indexed: 12/14/2022]
Abstract
Although the unique mechanism by which hepatitis B virus (HBV) polymerase primes reverse transcription is now well-characterized, the subsequent elongation process remains poorly understood. Reverse transcriptase (RT)-RNase H sequences from polymerase amino acid 304 (the C-terminal part of spacer domain) to 843 were expressed in Escherichia coli and purified partially. RT elongation activity was investigated using the fluorescent-tagged primer and homopolymeric RNA templates. RT elongation activity depended on both Mg2+ and Mn2+, and had low affinity for purine deoxynucleotides, which may be related with the success of adefovir, tenofovir, and entecavir. However, the polymerization rate was lower than that of human immunodeficiency virus RT. All HBV genotypes displayed similar RT activity, except for genotype B, which demonstrated increased elongation activity.
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Affiliation(s)
- Tetsuya Toyoda
- Choju Medical Institute, Fukushimura Hospital, 19-14 Azayamanaka, Noyori-Cho, Toyohashi, Aichi, 441-8124, Japan.
| | - Yongxiang Wang
- Key Laboratory of Medical Molecular Virology, Institute of Medical Microbiology, Shanghai Medical College, Fudan University, Shanghai, 200032, PR China
| | - Yumei Wen
- Key Laboratory of Medical Molecular Virology, Institute of Medical Microbiology, Shanghai Medical College, Fudan University, Shanghai, 200032, PR China
| | - Yasuhito Tanaka
- Department of Virology and Liver Unit, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan
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12
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Han J, Gong GZ, Lei JH, Qin WJ, Qin RH, Wang XY, Gu JX, Ren SF, Wen YM. Response to immune complex vaccine in chronic hepatitis B patients is associated with lower baseline level of serum IgG galactosylation. Medicine (Baltimore) 2019; 98:e16208. [PMID: 31261570 PMCID: PMC6617443 DOI: 10.1097/md.0000000000016208] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
The composition of glycan in immunoglobulin G (IgG) has shown to affect various diseases and can be regulated by drugs and preventive vaccination. A hepatitis B surface antigen (HBsAg)-hepatitis B immunoglobulin (HBIG) immune complex (YIC) therapeutic vaccine for chronic hepatitis B (CHB) patients has undergone clinical trials. To explore for markers of CHB, which could be associated with responsiveness to YIC therapeutic vaccine, serum IgG glycosylation in CHB patients was analyzed.Kinetic changes of serum galactosylated IgG in 53 hepatitis Be antigen (HBeAg)-positive CHB patients treated with YIC were monitored by matrix-assisted laser desorption/ionization (MALDI) mass spectrometry (MS) analysis. Whole blood cytokines were assayed by cytokine binding assay kits. All samples were back assayed before treatment, during therapy and follow-up for 6 months from a previous completed clinical trial.During YIC treatment, 26 patients with lower IgG galactosylation level at baseline [galactosylation level (Gal-ratio) = -0.29, 0.18 (mean, SD)] showed sustained increase of serum galactosylated IgG, and responded to YIC treatment by HBeAg seroconversion. While those who did not respond to YIC treatment [Gal-ratio = -0.40, 0.15 (mean, SD)] failed to show similar changes. Furthermore, this kinetic increase of galactosylated IgG correlated with marked up-regulated IL-2 level, confirming that effective cellular immune responses have participated in responsiveness.For HBeAg-positive CHB patients lower serum IgG galactosylation level may serve as an indicator for selecting a suitable subpopulation of candidates for YIC therapeutic vaccination.
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Affiliation(s)
- Jing Han
- Department of Biochemistry and Molecular Biology, NHC Key Laboratory of Glycoconjugates Research, School of Basic Medical Sciences, Shanghai Medical College, Fudan University
| | - Guo-Zhong Gong
- Department of Infectious Diseases, the Second Xiangya Hospital, Central South University, Changsha
| | - Jian-Hua Lei
- Department of Infectious Diseases, the Second Xiangya Hospital, Central South University, Changsha
| | - Wen-Jun Qin
- Department of Biochemistry and Molecular Biology, NHC Key Laboratory of Glycoconjugates Research, School of Basic Medical Sciences, Shanghai Medical College, Fudan University
| | - Rui-Huan Qin
- Department of Biochemistry and Molecular Biology, NHC Key Laboratory of Glycoconjugates Research, School of Basic Medical Sciences, Shanghai Medical College, Fudan University
| | - Xuan-Yi Wang
- Key Laboratory Medical Molecular Virology, Ministry of Education/Health, School of Basic Medical Sciences, Shanghai Medical College, Fudan University
- The Institutes of Biomedical Sciences, Shanghai Medical College, Fudan University, Shanghai, People's Republic of China
| | - Jian-Xin Gu
- Department of Biochemistry and Molecular Biology, NHC Key Laboratory of Glycoconjugates Research, School of Basic Medical Sciences, Shanghai Medical College, Fudan University
| | - Shi-Fang Ren
- Department of Biochemistry and Molecular Biology, NHC Key Laboratory of Glycoconjugates Research, School of Basic Medical Sciences, Shanghai Medical College, Fudan University
| | - Yu-Mei Wen
- Key Laboratory Medical Molecular Virology, Ministry of Education/Health, School of Basic Medical Sciences, Shanghai Medical College, Fudan University
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13
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Abstract
Hepatitis B virus (HBV) has infected one-third of world population, and 240 million people are chronic carriers, to whom a curative therapy is still not available. Similar to other viruses, persistent HBV infection relies on the virus to exploit host cell functions to support its replication and efficiently evade host innate and adaptive antiviral immunity. Understanding HBV replication and concomitant host cell interactions is thus instrumental for development of therapeutics to disrupt the virus-host interactions critical for its persistence and cure chronic hepatitis B. Although the currently available cell culture systems of HBV infection are refractory to genome-wide high throughput screening of key host cellular factors essential for and/or regulating HBV replication, classic one-gene (or pathway)-at-a-time studies in the last several decades have already revealed many aspects of HBV-host interactions. An overview of the landscape of HBV-hepatocyte interaction indicates that, in addition to more tightly suppressing viral replication by directly targeting viral proteins, disruption of key viral-host cell interactions to eliminate or inactivate the covalently closed circular (ccc) DNA, the most stable HBV replication intermediate that exists as an episomal minichromosome in the nucleus of infected hepatocyte, is essential to achieve a functional cure of chronic hepatitis B. Moreover, therapeutic targeting of integrated HBV DNA and their transcripts may also be required to induce hepatitis B virus surface antigen (HBsAg) seroclearance and prevent liver carcinogenesis.
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Affiliation(s)
- Jin Hu
- Baruch S. Blumberg Institute, 3805 Old Easton Road, Doylestown, Pennsylvania 18902, United States
- Institute of Medicinal Biotechnology, Chinese Academy of Medical Science, 1 Tian-tan Xi-li, Beijing, 100050, China
| | - Junjun Cheng
- Baruch S. Blumberg Institute, 3805 Old Easton Road, Doylestown, Pennsylvania 18902, United States
| | - Liudi Tang
- Microbiology and Immunology Graduate Program, Drexel University College of Medicine, 2900 West Queen Lane, Philadelphia, Pennsylvania 19129, United States
| | - Zhanying Hu
- Baruch S. Blumberg Institute, 3805 Old Easton Road, Doylestown, Pennsylvania 18902, United States
| | - Yue Luo
- Baruch S. Blumberg Institute, 3805 Old Easton Road, Doylestown, Pennsylvania 18902, United States
- Institute of Hepatology, Second Xiangya Hospital, Central South University, 87 Xiangya Road, Changsha, Hunan 410008, China
| | - Yuhuan Li
- Institute of Medicinal Biotechnology, Chinese Academy of Medical Science, 1 Tian-tan Xi-li, Beijing, 100050, China
| | - Tianlun Zhou
- Baruch S. Blumberg Institute, 3805 Old Easton Road, Doylestown, Pennsylvania 18902, United States
| | - Jinhong Chang
- Baruch S. Blumberg Institute, 3805 Old Easton Road, Doylestown, Pennsylvania 18902, United States
| | - Ju-Tao Guo
- Baruch S. Blumberg Institute, 3805 Old Easton Road, Doylestown, Pennsylvania 18902, United States
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14
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Ito N, Nakashima K, Sun S, Ito M, Suzuki T. Cell Type Diversity in Hepatitis B Virus RNA Splicing and Its Regulation. Front Microbiol 2019; 10:207. [PMID: 30800119 PMCID: PMC6375855 DOI: 10.3389/fmicb.2019.00207] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2018] [Accepted: 01/24/2019] [Indexed: 12/21/2022] Open
Abstract
Although RNA splicing of hepatitis B virus (HBV) is a commonly observed in livers of hepatitis B patients as well as in the cultured cells replicating the viral genome, its biological significance in the HBV life cycle and the detailed regulatory mechanisms are still largely unclear. In this study, we found cell-type dependency of HBV splicing of the 3.5 kb pregenomic RNA, which is efficiently spliced in human hepatoma cells but not in cells derived from human hepatic stellate, mouse hepatoma and human non-hepatic cells. It may be likely that RNA splicing is one of the determinants of host range restriction of HBV. Given the finding indicating the difference in cell-type dependency of the splicing efficiency between HBV and simian virus 40, we carried out intron-swapping experiments. The results suggest the presence of putative exonic splicing enhancer that possibly works in the cell-type dependent fashion. Together with further mutational analyses, a novel 50-nt intronic splicing silencer, whose secondary structure is well conserved among the HBV strains, was identified. It appears that this intronic silencer functions effectively independent of cell backgrounds.
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Affiliation(s)
- Noriomi Ito
- Department of Virology and Parasitology, Hamamatsu University School of Medicine, Shizuoka, Japan
| | - Kenji Nakashima
- Department of Virology and Parasitology, Hamamatsu University School of Medicine, Shizuoka, Japan
| | - Suofeng Sun
- Department of Virology and Parasitology, Hamamatsu University School of Medicine, Shizuoka, Japan
| | - Masahiko Ito
- Department of Virology and Parasitology, Hamamatsu University School of Medicine, Shizuoka, Japan
| | - Tetsuro Suzuki
- Department of Virology and Parasitology, Hamamatsu University School of Medicine, Shizuoka, Japan
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15
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Kostyusheva A, Kostyushev D, Brezgin S, Volchkova E, Chulanov V. Clinical Implications of Hepatitis B Virus RNA and Covalently Closed Circular DNA in Monitoring Patients with Chronic Hepatitis B Today with a Gaze into the Future: The Field Is Unprepared for a Sterilizing Cure. Genes (Basel) 2018; 9:E483. [PMID: 30301171 PMCID: PMC6210151 DOI: 10.3390/genes9100483] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2018] [Revised: 09/30/2018] [Accepted: 10/03/2018] [Indexed: 12/12/2022] Open
Abstract
. Chronic hepatitis B virus (HBV) infection has long remained a critical global health issue. Covalently closed circular DNA (cccDNA) is a persistent form of the HBV genome that maintains HBV chronicity. Decades of extensive research resulted in the two therapeutic options currently available: nucleot(s)ide analogs and interferon (IFN) therapy. A plethora of reliable markers to monitor HBV patients has been established, including the recently discovered encapsidated pregenomic RNA in serum, which can be used to determine treatment end-points and to predict the susceptibility of patients to IFN. Additionally, HBV RNA splice variants and cccDNA and its epigenetic modifications are associated with the clinical course and risks of hepatocellular carcinoma (HCC) and liver fibrosis. However, new antivirals, including CRISPR/Cas9, APOBEC-mediated degradation of cccDNA, and T-cell therapies aim at completely eliminating HBV, and it is clear that the diagnostic arsenal for defining the long-awaited sterilizing cure is missing. In this review, we discuss the currently available tools for detecting and measuring HBV RNAs and cccDNA, as well as the state-of-the-art in clinical implications of these markers, and debate needs and goals within the context of the sterilizing cure that is soon to come.
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Affiliation(s)
| | | | - Sergey Brezgin
- Central Research Institute of Epidemiology, Moscow, 111123, Russia.
- National Research Centre, Institute of Immunology, Federal Medical Biological Agency, Moscow, 115478, Russia.
| | - Elena Volchkova
- I.M. Sechenov First Moscow State Medical University, Ministry of Health of the Russian Federation, Moscow, 119146, Russia.
| | - Vladimir Chulanov
- Central Research Institute of Epidemiology, Moscow, 111123, Russia.
- I.M. Sechenov First Moscow State Medical University, Ministry of Health of the Russian Federation, Moscow, 119146, Russia.
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16
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Abstract
Chronic hepatitis B is a global health problem. The clinical outcomes of chronic hepatitis B infection include asymptomatic carrier state, chronic hepatitis (CH), liver cirrhosis (LC), and hepatocellular carcinoma (HCC). Because of the spontaneous error rate inherent to viral reverse transcriptase, the hepatitis B virus (HBV) genome evolves during the course of infection under the antiviral pressure of host immunity. The clinical significance of pre-S/S variants has become increasingly recognized in patients with chronic HBV infection. Pre-S/S variants are often identified in hepatitis B carriers with CH, LC, and HCC, which suggests that these naturally occurring pre-S/S variants may contribute to the development of progressive liver damage and hepatocarcinogenesis. This paper reviews the function of the pre-S/S region along with recent findings related to the role of pre-S/S variants in liver diseases. According to the mutation type, five pre-S/S variants have been identified: pre-S deletion, pre-S point mutation, pre-S1 splice variant, C-terminus S point mutation, and pre-S/S nonsense mutation. Their associations with HBV genotype and the possible pathogenesis of pre-S/S variants are discussed. Different pre-S/S variants cause liver diseases through different mechanisms. Most cause the intracellular retention of HBV envelope proteins and induction of endoplasmic reticulum stress, which results in liver diseases. Pre-S/S variants should be routinely determined in HBV carriers to help identify individuals who may be at a high risk of less favorable liver disease progression. Additional investigations are required to explore the molecular mechanisms of the pre-S/S variants involved in the pathogenesis of each stage of liver disease.
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Affiliation(s)
- Bing-Fang Chen
- School of Medicine, Fu-Jen Catholic University, New Taipei City 24205, Taiwan
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17
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Lin YM, Chen BF. A putative hepatitis B virus splice variant associated with chronic hepatitis and liver cirrhosis. Virology 2017; 510:224-233. [PMID: 28750326 DOI: 10.1016/j.virol.2017.07.025] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2017] [Revised: 07/19/2017] [Accepted: 07/20/2017] [Indexed: 02/07/2023]
Abstract
Hepatitis B virus (HBV) pre-S deletion was associated with chronic hepatitis (CH) and liver cirrhosis (LC); however, the type of pre-S deletion associated with these conditions and the mechanism of the generation of pre-S deletion remain unknown. Here, pre-S sequences from asymptomatic carriers (ASCs) and carriers with CH or LC were analyzed. The results indicated that deletion in the S promoter and the C-terminal half of the pre-S1 region was more frequent in CH and LC patients than in ASCs. RNA splicing analysis revealed that one type of pre-S1 deletion mutant, termed spPS1, was derived from splicing. This variant was associated with CH (12.7% vs. 1.8%, P = 0.06) and LC (14.5% vs. 1.8%, P = 0.032) when compared with ASC. In conclusion, spPS1, a putative splice variant; S promoter deletion mutant; and deletion in the C-terminal half of the pre-S1 region were closely associated with CH and LC development.
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Affiliation(s)
- Yu-Min Lin
- School of Medicine, Fu-Jen Catholic University, New Taipei City, Taiwan; Division of Gastroenterology, Department of Internal Medicine, Shin Kong Wu Ho-Su Memorial Hospital, Taipei, Taiwan
| | - Bing-Fang Chen
- School of Medicine, Fu-Jen Catholic University, New Taipei City, Taiwan.
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18
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Betz-Stablein BD, Töpfer A, Littlejohn M, Yuen L, Colledge D, Sozzi V, Angus P, Thompson A, Revill P, Beerenwinkel N, Warner N, Luciani F. Single-Molecule Sequencing Reveals Complex Genome Variation of Hepatitis B Virus during 15 Years of Chronic Infection following Liver Transplantation. J Virol 2016; 90:7171-83. [PMID: 27252524 DOI: 10.1128/JVI.00243-16] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2016] [Accepted: 05/10/2016] [Indexed: 12/22/2022] Open
Abstract
UNLABELLED Chronic hepatitis B (CHB) is prevalent worldwide. The infectious agent, hepatitis B virus (HBV), replicates via an RNA intermediate and is error prone, leading to the rapid generation of closely related but not identical viral variants, including those that can escape host immune responses and antiviral treatments. The complexity of CHB can be further enhanced by the presence of HBV variants with large deletions in the genome generated via splicing (spHBV variants). Although spHBV variants are incapable of autonomous replication, their replication is rescued by wild-type HBV. spHBV variants have been shown to enhance wild-type virus replication, and their prevalence increases with liver disease progression. Single-molecule deep sequencing was performed on whole HBV genomes extracted from samples, including the liver explant, longitudinally collected from a subject with CHB over a 15-year period after liver transplantation. By employing novel bioinformatics methods, this analysis showed that the dynamics of the viral population across a period of changing treatment regimens was complex. The spHBV variants detected in the liver explant remained present posttransplantation, and a highly diverse novel spHBV population as well as variants with multiple deletions in the pre-S genes emerged. The identification of novel mutations outside the HBV reverse transcriptase gene that co-occurred with known drug resistance-associated mutations highlights the relevance of using full-genome deep sequencing and supports the hypothesis that drug resistance involves interactions across the full length of the HBV genome. IMPORTANCE Single-molecule sequencing allowed the characterization, in unprecedented detail, of the evolution of HBV populations and offered unique insights into the dynamics of defective and spHBV variants following liver transplantation and complex treatment regimens. This analysis also showed the rapid adaptation of HBV populations to treatment regimens with evolving drug resistance phenotypes and evidence of purifying selection across the whole genome. Finally, the new open-source bioinformatics tools with the capacity to easily identify potential spliced variants from deep sequencing data are freely available.
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19
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Chen J, Wu M, Wang F, Zhang W, Wang W, Zhang X, Zhang J, Liu Y, Liu Y, Feng Y, Zheng Y, Hu Y, Yuan Z. Hepatitis B virus spliced variants are associated with an impaired response to interferon therapy. Sci Rep 2015; 5:16459. [PMID: 26585041 DOI: 10.1038/srep16459] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2015] [Accepted: 10/14/2015] [Indexed: 02/08/2023] Open
Abstract
During hepatitis B virus (HBV) replication, spliced HBV genomes and splice-generated proteins have been widely described, however, their biological and clinical significance remains to be defined. Here, an elevation of the proportion of HBV spliced variants in the sera of patients with chronic hepatitis B (CHB) is shown to correlate with an impaired respond to interferon-α (IFN-α) therapy. Transfection of the constructs encoding the three most dominant species of spliced variants into cells or ectopic expression of the two major spliced protein including HBSP and N-terminal-truncated viral polymerase protein result in strong suppression of IFN-α signaling transduction, while mutation of the major splicing-related sites of HBV attenuates the viral anti-IFN activities in both cell and mouse models. These results have associated the productions of HBV spliced variants with the failure response to IFN therapy and illuminate a novel mechanism where spliced viral products are employed to resist IFN-mediated host defense.
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20
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Zhang X, Zhu S, Zhu W, Li A, Zhu N. A Newly Identified Natural Splice Variant ASN Enhances Hepatitis B Virus Amplification. Viral Immunol 2015; 29:27-32. [PMID: 26501888 DOI: 10.1089/vim.2015.0044] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Chronic hepatitis B virus (HBV) infection causes approximately one-third of all the cases of liver cirrhosis and more than three-quarters of hepatocellular carcinoma (HCC) worldwide. There are eight different genotypes (A-H) of HBV, among which B and C are the major types of HBV in China. There is a positive correlation between viral load and level of viral splicing variants and the high risk of HCC. The aim of this study was to investigate the splicing variants of HBV circulating in HCC patients. Twenty-four carcinoma and adjacent liver tissues collected from HCC patients were studied. Using reverse transcription-polymerase chain reaction (RT-PCR) and sequencing, we identified a new type of natural splice variant with nucleotides 2448-489 and 910-2120 deleted, and we named it ASN. We also found that a higher viral load and splicing variant level existed in liver carcinoma tissues compared to paracarcinoma tissues. In the investigation of our splicing variant, we found its enhancing effect on HBV replication in vitro. Although splicing variants are not essential for the replication of HBV, they may have an important influence.
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Affiliation(s)
- Xiumin Zhang
- 1 Lab of Molecular Immunology, State Key Lab of Genetic Engineering, Institute of Biomedical Sciences (IBS), School of Life Sciences, Fudan University , Shanghai, People's Republic of China
| | - Sibo Zhu
- 1 Lab of Molecular Immunology, State Key Lab of Genetic Engineering, Institute of Biomedical Sciences (IBS), School of Life Sciences, Fudan University , Shanghai, People's Republic of China
| | - Wei Zhu
- 1 Lab of Molecular Immunology, State Key Lab of Genetic Engineering, Institute of Biomedical Sciences (IBS), School of Life Sciences, Fudan University , Shanghai, People's Republic of China
| | - Aijun Li
- 2 Oriental Liver Surgery Hospital, Second Military Medical University , Shanghai, People's Republic of China
| | - Naishuo Zhu
- 1 Lab of Molecular Immunology, State Key Lab of Genetic Engineering, Institute of Biomedical Sciences (IBS), School of Life Sciences, Fudan University , Shanghai, People's Republic of China
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21
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Abstract
Approximately 10.8% of human cancers are associated with infection by an oncogenic virus. These viruses include human papillomavirus (HPV), Epstein–Barr virus (EBV), Merkel cell polyomavirus (MCV), human T-cell leukemia virus 1 (HTLV-1), Kaposi's sarcoma-associated herpesvirus (KSHV), hepatitis C virus (HCV) and hepatitis B virus (HBV). These oncogenic viruses, with the exception of HCV, require the host RNA splicing machinery in order to exercise their oncogenic activities, a strategy that allows the viruses to efficiently export and stabilize viral RNA and to produce spliced RNA isoforms from a bicistronic or polycistronic RNA transcript for efficient protein translation. Infection with a tumor virus affects the expression of host genes, including host RNA splicing factors, which play a key role in regulating viral RNA splicing of oncogene transcripts. A current prospective focus is to explore how alternative RNA splicing and the expression of viral oncogenes take place in a cell- or tissue-specific manner in virus-induced human carcinogenesis.
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Affiliation(s)
- Masahiko Ajiro
- Tumor Virus RNA Biology Section, Gene Regulation and Chromosome Biology Laboratory, Center for Cancer Research, National Cancer Institute, National Institutes of Health , Frederick, MD 21702, USA
| | - Zhi-Ming Zheng
- Tumor Virus RNA Biology Section, Gene Regulation and Chromosome Biology Laboratory, Center for Cancer Research, National Cancer Institute, National Institutes of Health , Frederick, MD 21702, USA
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22
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Rodriguez-Frias F, Buti M, Tabernero D, Homs M. Quasispecies structure, cornerstone of hepatitis B virus infection: Mass sequencing approach. World J Gastroenterol 2013; 19:6995-7023. [PMID: 24222943 PMCID: PMC3819535 DOI: 10.3748/wjg.v19.i41.6995] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/28/2013] [Revised: 07/23/2013] [Accepted: 09/17/2013] [Indexed: 02/06/2023] Open
Abstract
Hepatitis B virus (HBV) is a DNA virus with complex replication, and high replication and mutation rates, leading to a heterogeneous viral population. The population is comprised of genomes that are closely related, but not identical; hence, HBV is considered a viral quasispecies. Quasispecies variability may be somewhat limited by the high degree of overlapping between the HBV coding regions, which is especially important in the P and S gene overlapping regions, but is less significant in the X and preCore/Core genes. Despite this restriction, several clinically and pathologically relevant variants have been characterized along the viral genome. Next-generation sequencing (NGS) approaches enable high-throughput analysis of thousands of clonally amplified regions and are powerful tools for characterizing genetic diversity in viral strains. In the present review, we update the information regarding HBV variability and present a summary of the various NGS approaches available for research in this virus. In addition, we provide an analysis of the clinical implications of HBV variants and their study by NGS.
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23
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Bayliss J, Lim L, Thompson AJV, Desmond P, Angus P, Locarnini S, Revill PA. Hepatitis B virus splicing is enhanced prior to development of hepatocellular carcinoma. J Hepatol 2013; 59:1022-8. [PMID: 23811301 DOI: 10.1016/j.jhep.2013.06.018] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/25/2013] [Revised: 06/04/2013] [Accepted: 06/18/2013] [Indexed: 12/20/2022]
Abstract
BACKGROUND & AIMS The hepatitis B virus (HBV) genome encodes specific sequence elements which promote splicing of viral DNA. It has been previously suggested that spliced HBV (spHBV) variants promote viral replication and protein production, leading to hepatocellular carcinoma (HCC). In this study, we have analysed changes in spHBV over time; providing the first longitudinal analysis of spHBV in relation to the development of HCC. METHODS Serial serum samples were collected from 165 patients with chronic HBV monoinfection, including 58 patients who later developed HCC. Real-time PCR was used to amplify and quantify wt and sp DNA loads. RESULTS spHBV was detected in over 80% of patients with chronic HBV infection. Median serum spHBV levels were significantly higher in HCC patients than HCC-free control patients (p<0.001). Univariate analysis revealed a strong correlation between time to HCC diagnosis and spHBV DNA levels (τ=0.203; p=0.016). Asian HBV genotype (p=0.025) and increased viral load (p<0.001) were also significantly associated with increased spHBV DNA levels. Multiple regression analysis revealed time to diagnosis of HCC, Asian HBV genotypes, and viral load to be associated with increased spHBV DNA (model p<0.001; R(2)=0.189). CONCLUSIONS HBV splicing is a common event during chronic infection and increases prior to diagnosis of HCC. Measurement of HBV splicing may prove a valuable adjunct to be used in the identification of chronically infected patients who are at increased risk of developing HCC.
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Affiliation(s)
- Julianne Bayliss
- Division of Molecular Research and Development, Victorian Infectious Diseases Reference Laboratory, North Melbourne, Victoria 3051, Australia.
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24
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Huang C, Xie MH, Liu W, Yang B, Yang F, Huang J, Huang J, Wu Q, Fu XD, Zhang Y. A structured RNA in hepatitis B virus post-transcriptional regulatory element represses alternative splicing in a sequence-independent and position-dependent manner. FEBS J 2011; 278:1533-46. [PMID: 21371260 DOI: 10.1111/j.1742-4658.2011.08077.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Hepatitis B virus (HBV) transcripts are subjected to multiple splicing decisions, but the mechanism of splicing regulation remains poorly understood. In this study, we used a well-investigated alternative splicing reporter to dissect splicing regulatory elements residing in the post-transcriptional regulatory element (PRE) of HBV. A strong intronic splicing silencer (ISS) with a minimal functional element of 105 nucleotides (referred to as PRE-ISS) was identified and, interestingly, both the sense and antisense strands of the element were found to strongly suppress alternative splicing in multiple human cell lines. PRE-ISS folds into a double-hairpin structure, in which substitution mutations disrupting the double-hairpin structure abolish the splicing silencer activity. Although it harbors two previously identified binding sites for polypyrimidine tract binding protein, PRE-ISS represses splicing independent of this protein. The silencing function of PRE-ISS exhibited a strong position dependence, decreasing with the distance from affected splice sites. PRE-ISS does not belong to the intronic region of any HBV splicing variants identified thus far, preventing the testing of this intronic silencer function in the regulation of HBV splicing. These findings, together with the identification of multiple sense-antisense ISSs in the HBV genome, support the hypothesis that a sequence-independent and structure-dependent regulatory mechanism may have evolved to repress cryptic splice sites in HBV transcripts, thereby preventing their aberrant splicing during viral replication in the host.
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Affiliation(s)
- Chen Huang
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Hubei, China
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25
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Abstract
Posttranscriptional regulation of gene expression is increasingly recognized as a model for inherited and acquired disease. Recent work has expanded understanding of the range of mechanisms that regulate several of these distinct steps, including messenger RNA (mRNA) splicing, trafficking, and/or stability. Each of these pathways is implicated in disease pathogenesis, and each represents important avenues for therapeutic intervention. This review summarizes important mechanisms controlling mRNA processing and the regulation of mRNA degradation, including the role of microRNAs and RNA binding proteins. These pathways provide important opportunities for therapeutic targeting directed at splicing and degradation in order to attenuate genetic defects in RNA metabolism. We will highlight developments in vector development and validation for therapeutic manipulation of mRNA expression with a focus on potential applications in metabolic and immunomediated liver disease.
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Affiliation(s)
| | - Nicholas O. Davidson
- Contact information: Nicholas O. Davidson, MD, Division of Gastroenterology, Box 8124, Washington University School of Medicine, 660. Euclid Avenue, St. Louis, MO 63110, Phone: (314)-362-2027,
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