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Yu Y, Kass MA, Zhang M, Youssef N, Freije CA, Brock KP, Aguado LC, Seifert LL, Venkittu S, Hong X, Shlomai A, de Jong YP, Marks DS, Rice CM, Schneider WM. Deep mutational scanning of hepatitis B virus reveals a mechanism for cis-preferential reverse transcription. Cell 2024; 187:2735-2745.e12. [PMID: 38723628 PMCID: PMC11127778 DOI: 10.1016/j.cell.2024.04.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2023] [Revised: 02/12/2024] [Accepted: 04/10/2024] [Indexed: 05/22/2024]
Abstract
Hepatitis B virus (HBV) is a small double-stranded DNA virus that chronically infects 296 million people. Over half of its compact genome encodes proteins in two overlapping reading frames, and during evolution, multiple selective pressures can act on shared nucleotides. This study combines an RNA-based HBV cell culture system with deep mutational scanning (DMS) to uncouple cis- and trans-acting sequence requirements in the HBV genome. The results support a leaky ribosome scanning model for polymerase translation, provide a fitness map of the HBV polymerase at single-nucleotide resolution, and identify conserved prolines adjacent to the HBV polymerase termination codon that stall ribosomes. Further experiments indicated that stalled ribosomes tether the nascent polymerase to its template RNA, ensuring cis-preferential RNA packaging and reverse transcription of the HBV genome.
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Affiliation(s)
- Yingpu Yu
- Laboratory of Virology and Infectious Disease, The Rockefeller University, New York, NY 10065, USA
| | - Maximilian A Kass
- Laboratory of Virology and Infectious Disease, The Rockefeller University, New York, NY 10065, USA; Department of Infectious Diseases, Molecular Virology, Heidelberg University, Medical Faculty Heidelberg, Heidelberg, Germany
| | - Mengyin Zhang
- Laboratory of Virology and Infectious Disease, The Rockefeller University, New York, NY 10065, USA
| | - Noor Youssef
- Department of Systems Biology, Harvard Medical School, Boston, MA 02115, USA; Department of Organismic and Evolutionary Biology, Broad Institute of MIT and Harvard, Harvard University, Cambridge, MA 02138, USA
| | - Catherine A Freije
- Laboratory of Virology and Infectious Disease, The Rockefeller University, New York, NY 10065, USA
| | - Kelly P Brock
- Department of Systems Biology, Harvard Medical School, Boston, MA 02115, USA; Department of Organismic and Evolutionary Biology, Broad Institute of MIT and Harvard, Harvard University, Cambridge, MA 02138, USA
| | - Lauren C Aguado
- Laboratory of Virology and Infectious Disease, The Rockefeller University, New York, NY 10065, USA
| | - Leon L Seifert
- Laboratory of Virology and Infectious Disease, The Rockefeller University, New York, NY 10065, USA; Center for Clinical and Translational Science, The Rockefeller University, New York, NY 10065, USA
| | - Sanjana Venkittu
- Laboratory of Virology and Infectious Disease, The Rockefeller University, New York, NY 10065, USA
| | - Xupeng Hong
- Laboratory of Virology and Infectious Disease, The Rockefeller University, New York, NY 10065, USA
| | - Amir Shlomai
- Laboratory of Virology and Infectious Disease, The Rockefeller University, New York, NY 10065, USA
| | - Ype P de Jong
- Laboratory of Virology and Infectious Disease, The Rockefeller University, New York, NY 10065, USA; Division of Gastroenterology and Hepatology, Weill Cornell Medical College, New York, NY 10065, USA
| | - Debora S Marks
- Department of Systems Biology, Harvard Medical School, Boston, MA 02115, USA; Department of Organismic and Evolutionary Biology, Broad Institute of MIT and Harvard, Harvard University, Cambridge, MA 02138, USA
| | - Charles M Rice
- Laboratory of Virology and Infectious Disease, The Rockefeller University, New York, NY 10065, USA.
| | - William M Schneider
- Laboratory of Virology and Infectious Disease, The Rockefeller University, New York, NY 10065, USA.
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2
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Gómez-Moreno A, Ploss A. Mechanisms of Hepatitis B Virus cccDNA and Minichromosome Formation and HBV Gene Transcription. Viruses 2024; 16:609. [PMID: 38675950 PMCID: PMC11054251 DOI: 10.3390/v16040609] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2024] [Revised: 04/11/2024] [Accepted: 04/13/2024] [Indexed: 04/28/2024] Open
Abstract
Hepatitis B virus (HBV) is the etiologic agent of chronic hepatitis B, which puts at least 300 million patients at risk of developing fibrosis, cirrhosis, and hepatocellular carcinoma. HBV is a partially double-stranded DNA virus of the Hepadnaviridae family. While HBV was discovered more than 50 years ago, many aspects of its replicative cycle remain incompletely understood. Central to HBV persistence is the formation of covalently closed circular DNA (cccDNA) from the incoming relaxed circular DNA (rcDNA) genome. cccDNA persists as a chromatinized minichromosome and is the major template for HBV gene transcription. Here, we review how cccDNA and the viral minichromosome are formed and how viral gene transcription is regulated and highlight open questions in this area of research.
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Affiliation(s)
| | - Alexander Ploss
- Department of Molecular Biology, Princeton University, Princeton, NJ 08544, USA
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Wang J, Yuan X, Wang Y, Zhang Y, Han M, Lu H, Liu S, Zhang Y, Ge F, Liu Y, Cheng J. PreS1BP mediates inhibition of Hepatitis B virus replication by promoting HBx protein degradation. Virus Res 2024; 341:199326. [PMID: 38253259 PMCID: PMC10846407 DOI: 10.1016/j.virusres.2024.199326] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2023] [Revised: 01/07/2024] [Accepted: 01/18/2024] [Indexed: 01/24/2024]
Abstract
BACKGROUND PreS1-binding protein (PreS1BP), recognized as a nucleolar protein and tumor suppressor, influences the replication of various viruses, including vesicular stomatitis virus (VSV) and herpes simplex virus type 1 (HSV-1). Its role in hepatitis B virus (HBV) replication and the underlying mechanisms, however, remain elusive. METHODS We investigated PreS1BP expression levels in an HBV-replicating cell and animal model and analyzed the impact of its overexpression on viral replication metrics. HBV DNA, covalently closed circular DNA (cccDNA), hepatitis B surface antigen (HBsAg), hepatitis B core antigen (HBcAg), and HBV RNA levels were assessed in HBV-expressing stable cell lines under varying PreS1BP conditions. Furthermore, co-immunoprecipitation and ubiquitination assays were used to detect PreS1BP- hepatitis B virus X protein (HBx) interactions and HBx stability modulated by PreS1BP. RESULTS Our study revealed a marked decrease in PreS1BP expression in the presence of active HBV replication. Functional assays showed that PreS1BP overexpression significantly inhibited HBV replication and transcription, evidenced by the reduction in HBV DNA, cccDNA, HBsAg, HBcAg, and HBV RNA levels. At the molecular level, PreS1BP facilitated the degradation of HBx in a dose-dependent fashion, whereas siRNA-mediated knockdown of PreS1BP led to an increase in HBx levels. Subsequent investigations uncovered that PreS1BP accelerated HBx protein degradation via K63-linked ubiquitination in a ubiquitin-proteasome system-dependent manner. Co-immunoprecipitation assays further established that PreS1BP enhances the recruitment of the proteasome 20S subunit alpha 3 (PSMA3) for interaction with HBx, thereby fostering its degradation. CONCLUSIONS These findings unveil a previously unidentified mechanism wherein PreS1BP mediates HBx protein degradation through the ubiquitin-proteasome system, consequentially inhibiting HBV replication. This insight positions PreS1BP as a promising therapeutic target for future HBV interventions. Further studies are warranted to explore the clinical applicability of modulating PreS1BP in HBV therapy.
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Affiliation(s)
- Jun Wang
- Peking University Ditan Teaching Hospital, Beijing 100015, China; Beijing Key Laboratory of Emerging Infectious Diseases, Institute of Infectious Diseases, Beijing Ditan Hospital, Capital Medical University, Beijing 100015, China
| | - Xiaoxue Yuan
- Beijing Key Laboratory of Emerging Infectious Diseases, Institute of Infectious Diseases, Beijing Ditan Hospital, Capital Medical University, Beijing 100015, China; The Division of Liver Diseases, Beijing Ditan Hospital, Capital Medical University, Beijing 100015, China
| | - Yun Wang
- The Division of Liver Diseases, Beijing Ditan Hospital, Capital Medical University, Beijing 100015, China
| | - Yu Zhang
- The Division of Liver Diseases, Beijing Ditan Hospital, Capital Medical University, Beijing 100015, China
| | - Ming Han
- Beijing Key Laboratory of Emerging Infectious Diseases, Institute of Infectious Diseases, Beijing Ditan Hospital, Capital Medical University, Beijing 100015, China; The Division of Liver Diseases, Beijing Ditan Hospital, Capital Medical University, Beijing 100015, China
| | - Hongping Lu
- Hebei Utu Pharmaceutical Company Ltd, Shijiazhuang, Hebei Province 052165, China
| | - Shunai Liu
- Beijing Key Laboratory of Emerging Infectious Diseases, Institute of Infectious Diseases, Beijing Ditan Hospital, Capital Medical University, Beijing 100015, China; The Division of Liver Diseases, Beijing Ditan Hospital, Capital Medical University, Beijing 100015, China
| | - Yang Zhang
- Beijing Key Laboratory of Emerging Infectious Diseases, Institute of Infectious Diseases, Beijing Ditan Hospital, Capital Medical University, Beijing 100015, China
| | - Feilin Ge
- Department of Chinese Medicine, the First Affiliated Hospital of Zhengzhou University, Zhengzhou 450052, China
| | - Yan Liu
- Department of Infectious Diseases, The Fifth Medical Center of Chinese PLA General Hospital, Beijing 100039, China.
| | - Jun Cheng
- Peking University Ditan Teaching Hospital, Beijing 100015, China; Hebei Utu Pharmaceutical Company Ltd, Shijiazhuang, Hebei Province 052165, China.
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4
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Jin Y, Wang S, Xu S, Zhao S, Xu X, Poongavanam V, Menéndez-Arias L, Zhan P, Liu X. Targeting hepatitis B virus cccDNA levels: recent progress in seeking small molecule drug candidates. Drug Discov Today 2023; 28:103617. [PMID: 37196762 DOI: 10.1016/j.drudis.2023.103617] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2023] [Revised: 03/29/2023] [Accepted: 05/10/2023] [Indexed: 05/19/2023]
Abstract
Hepatitis B virus (HBV) infection is a major global health problem that puts people at high risk of death from cirrhosis and liver cancer. The presence of covalently closed circular DNA (cccDNA) in infected cells is considered to be the main obstacle to curing chronic hepatitis B. At present, the cccDNA cannot be completely eliminated by standard treatments. There is an urgent need to develop drugs or therapies that can reduce HBV cccDNA levels in infected cells. We summarize the discovery and optimization of small molecules that target cccDNA synthesis and degradation. These compounds are cccDNA synthesis inhibitors, cccDNA reducers, core protein allosteric modulators, ribonuclease H inhibitors, cccDNA transcriptional modulators, HBx inhibitors and other small molecules that reduce cccDNA levels. Teaser: HBV covalently closed circular DNA (cccDNA) can be stably maintained in infected cells for a prolonged period, and this is the fundamental reason why hepatitis B cannot be completely cured. Here, we review recent progress in the development of small molecules that can reduce cccDNA levels in infected cells.
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Affiliation(s)
- Yu Jin
- Department of Medicinal Chemistry, Key Laboratory of Chemical Biology (Ministry of Education), School of Pharmaceutical Sciences, Shandong University, 44 West Culture Road, 250012 Jinan, Shandong, PR China
| | - Shuo Wang
- Department of Medicinal Chemistry, Key Laboratory of Chemical Biology (Ministry of Education), School of Pharmaceutical Sciences, Shandong University, 44 West Culture Road, 250012 Jinan, Shandong, PR China
| | - Shujing Xu
- Department of Medicinal Chemistry, Key Laboratory of Chemical Biology (Ministry of Education), School of Pharmaceutical Sciences, Shandong University, 44 West Culture Road, 250012 Jinan, Shandong, PR China
| | - Shujie Zhao
- Department of Medicinal Chemistry, Key Laboratory of Chemical Biology (Ministry of Education), School of Pharmaceutical Sciences, Shandong University, 44 West Culture Road, 250012 Jinan, Shandong, PR China
| | - Xiangrui Xu
- Department of Medicinal Chemistry, Key Laboratory of Chemical Biology (Ministry of Education), School of Pharmaceutical Sciences, Shandong University, 44 West Culture Road, 250012 Jinan, Shandong, PR China
| | - Vasanthanathan Poongavanam
- Department of Physics, Chemistry and Pharmacy, University of Southern Denmark, Odense M, DK-5230, Denmark
| | - Luis Menéndez-Arias
- Centro de Biología Molecular 'Severo Ochoa' (Consejo Superior de Investigaciones Científicas & Universidad Autónoma de Madrid), 28049 Madrid, Spain.
| | - Peng Zhan
- Department of Medicinal Chemistry, Key Laboratory of Chemical Biology (Ministry of Education), School of Pharmaceutical Sciences, Shandong University, 44 West Culture Road, 250012 Jinan, Shandong, PR China.
| | - Xinyong Liu
- Department of Medicinal Chemistry, Key Laboratory of Chemical Biology (Ministry of Education), School of Pharmaceutical Sciences, Shandong University, 44 West Culture Road, 250012 Jinan, Shandong, PR China.
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5
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He L, Shen H, Deng H, Zhang X, Xu Y, Shi C, Ouyang Z. Identification of critical residues in the regulatory protein HBx for Smc5/6 interaction and hepatitis B virus production. Antiviral Res 2023; 211:105519. [PMID: 36592669 DOI: 10.1016/j.antiviral.2022.105519] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2022] [Revised: 12/13/2022] [Accepted: 12/28/2022] [Indexed: 01/01/2023]
Abstract
The host structural maintenance of chromosomes 5/6 complex (Smc5/6) is a restriction factor of hepatitis B virus (HBV) that inhibits the transcription of viral ccDNA. HBV antagonizes this restriction by expressing the regulatory X protein (HBx) which targets Smc5/6 for degradation via DNA damage-binding protein 1 (DDB1) E3 ubiquitin ligase. However, the molecular insights into how Smc5/6 interacts with HBx remain elusive. In this study, we systematically investigated the interaction between Smc5/6 and HBx. Smc5/6 interacts with HBx through multiple sites in the absence of DDB1 in the pull-down assay. HBx C-terminal is sufficient for the interaction. Most importantly, residue Phe132, which is strictly conserved in all HBV subtypes, is critical for interaction with Smc5/6 both in vitro and in vivo. Mutation of this site (F132A) results in defect in Smc5/6 interaction, extrachromosomal reporter transcription, and HBV production both in cells and in mouse model. Collectively, our data identifies a key residue on HBx for Smc5/6 interaction and viral production. These results provide valuable information for both basic research and therapeutic drugs targeting HBx.
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Affiliation(s)
- Lili He
- Department of Pathogen Biology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, 13 Hangkong Road, Wuhan, Hubei province, 430030, China
| | - Huanyu Shen
- Department of Pathogen Biology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, 13 Hangkong Road, Wuhan, Hubei province, 430030, China
| | - Hui Deng
- Department of Pathogen Biology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, 13 Hangkong Road, Wuhan, Hubei province, 430030, China
| | - Xiaoyan Zhang
- Department of Pathogen Biology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, 13 Hangkong Road, Wuhan, Hubei province, 430030, China
| | - Yang Xu
- Department of Pathogen Biology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, 13 Hangkong Road, Wuhan, Hubei province, 430030, China
| | - Chunwei Shi
- Department of Pathogen Biology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, 13 Hangkong Road, Wuhan, Hubei province, 430030, China
| | - Zhuqing Ouyang
- Department of Pathogen Biology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, 13 Hangkong Road, Wuhan, Hubei province, 430030, China.
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6
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Kim ET, Kim KD. Topological implications of DNA tumor viral episomes. BMB Rep 2022; 55:587-594. [PMID: 36379513 PMCID: PMC9813422] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2022] [Indexed: 12/29/2022] Open
Abstract
A persistent DNA tumor virus infection transforms normal cells into cancer cells by either integrating its genome into host chromosomes or retaining it as an extrachromosomal entity called episome. Viruses have evolved mechanisms for attaching episomes to infected host cell chromatin to efficiently segregate the viral genome during mitosis. It has been reported that viral episome can affect the gene expression of the host chromosomes through interactions between viral episomes and epigenetic regulatory host factors. This mini review summarizes our current knowledge of the tethering sites of viral episomes, such as EBV, KSHV, and HBV, on host chromosomes analyzed by three-dimensional genomic tools. [BMB Reports 2022; 55(12): 587-594].
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Affiliation(s)
- Eui Tae Kim
- Department of Microbiology and Immunology, Jeju National University College of Medicine, Jeju 63241, Korea,Department of Biomedicine & Drug Development, Jeju National University, Jeju 63241, Korea
| | - Kyoung-Dong Kim
- Department of Systems Biotechnology, Chung-Ang University, Anseong 17546, Korea,Corresponding author. Tel: +82-31-670-3359; Fax: +82-31-675-3108; E-mail:
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7
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Gilmore SA, Tam D, Cheung TL, Snyder C, Farand J, Dick R, Matles M, Feng JY, Ramirez R, Li L, Yu H, Xu Y, Barnes D, Czerwieniec G, Brendza KM, Appleby TC, Birkus G, Willkom M, Kobayashi T, Paoli E, Labelle M, Boesen T, Tay CH, Delaney WE, Notte GT, Schmitz U, Feierbach B. Characterization of a KDM5 small molecule inhibitor with antiviral activity against hepatitis B virus. PLoS One 2022; 17:e0271145. [PMID: 36477212 PMCID: PMC9728921 DOI: 10.1371/journal.pone.0271145] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2022] [Accepted: 11/14/2022] [Indexed: 12/12/2022] Open
Abstract
Chronic hepatitis B (CHB) is a global health care challenge and a major cause of liver disease. To find new therapeutic avenues with a potential to functionally cure chronic Hepatitis B virus (HBV) infection, we performed a focused screen of epigenetic modifiers to identify potential inhibitors of replication or gene expression. From this work we identified isonicotinic acid inhibitors of the histone lysine demethylase 5 (KDM5) with potent anti-HBV activity. To enhance the cellular permeability and liver accumulation of the most potent KDM5 inhibitor identified (GS-080) an ester prodrug was developed (GS-5801) that resulted in improved bioavailability and liver exposure as well as an increased H3K4me3:H3 ratio on chromatin. GS-5801 treatment of HBV-infected primary human hepatocytes reduced the levels of HBV RNA, DNA and antigen. Evaluation of GS-5801 antiviral activity in a humanized mouse model of HBV infection, however, did not result in antiviral efficacy, despite achieving pharmacodynamic levels of H3K4me3:H3 predicted to be efficacious from the in vitro model. Here we discuss potential reasons for the disconnect between in vitro and in vivo efficacy, which highlight the translational difficulties of epigenetic targets for viral diseases.
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Affiliation(s)
- Sarah A. Gilmore
- Gilead Sciences, Inc., Foster City, California, United States America
| | - Danny Tam
- Gilead Sciences, Inc., Foster City, California, United States America
| | - Tara L. Cheung
- Gilead Sciences, Inc., Foster City, California, United States America
| | - Chelsea Snyder
- Gilead Sciences, Inc., Foster City, California, United States America
| | - Julie Farand
- Gilead Sciences, Inc., Foster City, California, United States America
| | - Ryan Dick
- Gilead Sciences, Inc., Foster City, California, United States America
| | - Mike Matles
- Gilead Sciences, Inc., Foster City, California, United States America
| | - Joy Y. Feng
- Gilead Sciences, Inc., Foster City, California, United States America
| | - Ricardo Ramirez
- Gilead Sciences, Inc., Foster City, California, United States America
| | - Li Li
- Gilead Sciences, Inc., Foster City, California, United States America
| | - Helen Yu
- Gilead Sciences, Inc., Foster City, California, United States America
| | - Yili Xu
- Gilead Sciences, Inc., Foster City, California, United States America
| | - Dwight Barnes
- Gilead Sciences, Inc., Foster City, California, United States America
| | - Gregg Czerwieniec
- Gilead Sciences, Inc., Foster City, California, United States America
| | | | - Todd C. Appleby
- Gilead Sciences, Inc., Foster City, California, United States America
| | - Gabriel Birkus
- Gilead Sciences, Inc., Foster City, California, United States America
| | - Madeleine Willkom
- Gilead Sciences, Inc., Foster City, California, United States America
| | - Tetsuya Kobayashi
- Gilead Sciences, Inc., Foster City, California, United States America
| | - Eric Paoli
- Gilead Sciences, Inc., Foster City, California, United States America
| | | | - Thomas Boesen
- EpiTherapeutics ApS, Copenhagen, Denmark
- Novo Nordisk A/S, Bagsvaerd, Denmark
| | - Chin H. Tay
- Gilead Sciences, Inc., Foster City, California, United States America
| | | | - Gregory T. Notte
- Gilead Sciences, Inc., Foster City, California, United States America
| | - Uli Schmitz
- Gilead Sciences, Inc., Foster City, California, United States America
- * E-mail:
| | - Becket Feierbach
- Gilead Sciences, Inc., Foster City, California, United States America
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8
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Abstract
Hepatitis B virus (HBV)‐related diseases are among the major diseases that affect millions of people worldwide. These diseases are difficult to eradicate and thus pose a serious global health challenge. There is an urgent need to understand the cross talk mechanism between HBV and the host. Cholesterol‐25‐hydroxylase (CH25H) and its enzymatic product, 25‐hydroxycholesterol (25HC), were previously shown to exhibit effective broad‐spectrum antiviral activity. However, the role of CH25H in the regulation of HBV infection and replication remains unclear. The present study reported increased expression of CH25H in HBV-infected patients compared to healthy subjects. Importantly, higher expression of CH25H expression was found to be associated with low HBV replication. Additionally, the present study aimed to identify CH25H mutants, which would lack hydroxylase activity but retain antiviral activity toward HBV infection and replication. Interestingly, it was observed that both CH25H and its mutants interacted with HBx protein and inhibited nuclear translocation of HBx. In particular, CH25H interacted with the C-terminal region of HBx, while transmembrane region 3 of CH25H was found to be critical for CH25H–HBx interaction and inhibition of HBV replication. The study results suggested that 25HC promoted HBV infection but not HBV replication. Thus, the results of the present study suggested the involvement of a dual mechanism in CH25H-mediated regulation of HBV replication. The study clearly demonstrated cross talk between HBV and the host through CH25H–HBx axis.
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9
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Sun Y, Teng Y, Wang L, Zhang Z, Chen C, Wang Y, Zhang X, Xiang P, Song X, Lu J, Li N, Gao L, Liang X, Xia Y, Wu Z, Ma C. LINC01431 Promotes Histone H4R3 Methylation to Impede HBV Covalently Closed Circular DNA Transcription by Stabilizing PRMT1. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2022; 9:e2103135. [PMID: 35398991 PMCID: PMC9165498 DOI: 10.1002/advs.202103135] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/21/2021] [Revised: 03/11/2022] [Indexed: 06/14/2023]
Abstract
Covalently closed circular DNA (cccDNA) is the transcriptional template of hepatitis B virus (HBV), which interacts with both host and viral proteins to form minichromosome in the nucleus and is resistant to antiviral agents. Identification of host factors involved in cccDNA transcriptional regulation is expected to prove a new venue for HBV therapy. Recent evidence suggests the involvement of long noncoding RNAs (lncRNAs) in mediating the interaction of host factors with various viruses, however, lncRNAs that HBV targets and represses cccDNA transcription have not been fully elucidated. Here, the authors identified LINC01431 as a novel host restriction factor for HBV transcription. Mechanically, LINC01431 competitively bound with type I protein arginine methyltransferase (PRMT1) to block the HBx-mediated PRMT1 ubiquitination and degradation. Consequently, LINC01431 increased the occupancy of PRMT1 on cccDNA, leading to enhanced H4R3me2a modification and reduced acetylation of cccDNA-bound histones, thereby repressing cccDNA transcription. In turn, to facilitate viral replication, HBV transcriptionally repressed LINC01431 expression by HBx-mediated repression of transcription factor Zinc fingers and homeoboxes 2 (ZHX2). Collectively, the study demonstrates LINC01431 as a novel epigenetic regulator of cccDNA minichromosome and highlights a feedback loop of HBx-LINC01431-PRMT1 in HBV replication, which provides potential therapeutic targets for HBV treatment.
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Affiliation(s)
- Yang Sun
- Key Laboratory for Experimental Teratology of Ministry of Education and Department of ImmunologySchool of Basic Medical SciencesCheeloo Medical CollegeShandong UniversityJinanShandong250012China
| | - Yan Teng
- State Key Laboratory of Virology and Hubei Province Key Laboratory of Allergy and ImmunologyInstitute of Medical VirologySchool of Basic Medical SciencesWuhan UniversityWuhanHubei430072China
| | - Liyuan Wang
- Key Laboratory for Experimental Teratology of Ministry of Education and Department of ImmunologySchool of Basic Medical SciencesCheeloo Medical CollegeShandong UniversityJinanShandong250012China
| | - Zhaoying Zhang
- Key Laboratory for Experimental Teratology of Ministry of Education and Department of ImmunologySchool of Basic Medical SciencesCheeloo Medical CollegeShandong UniversityJinanShandong250012China
| | - ChaoJia Chen
- Key Laboratory for Experimental Teratology of Ministry of Education and Department of ImmunologySchool of Basic Medical SciencesCheeloo Medical CollegeShandong UniversityJinanShandong250012China
| | - Yingchun Wang
- Key Laboratory for Experimental Teratology of Ministry of Education and Department of ImmunologySchool of Basic Medical SciencesCheeloo Medical CollegeShandong UniversityJinanShandong250012China
| | - Xiaodong Zhang
- Key Laboratory for Experimental Teratology of Ministry of Education and Department of ImmunologySchool of Basic Medical SciencesCheeloo Medical CollegeShandong UniversityJinanShandong250012China
| | - Peng Xiang
- Key Laboratory for Experimental Teratology of Ministry of Education and Department of ImmunologySchool of Basic Medical SciencesCheeloo Medical CollegeShandong UniversityJinanShandong250012China
| | - Xiaojia Song
- Key Laboratory for Experimental Teratology of Ministry of Education and Department of ImmunologySchool of Basic Medical SciencesCheeloo Medical CollegeShandong UniversityJinanShandong250012China
| | - Jinghui Lu
- Department of Hepatobiliary SurgeryQilu Hospital of Shandong University, JinanShandong250012China
| | - Nailin Li
- Karolinska InstituteDepartment of Medicine‐SolnaClinical Pharmacology GroupStockholm17176Sweden
| | - Lifen Gao
- Key Laboratory for Experimental Teratology of Ministry of Education and Department of ImmunologySchool of Basic Medical SciencesCheeloo Medical CollegeShandong UniversityJinanShandong250012China
| | - Xiaohong Liang
- Key Laboratory for Experimental Teratology of Ministry of Education and Department of ImmunologySchool of Basic Medical SciencesCheeloo Medical CollegeShandong UniversityJinanShandong250012China
| | - Yuchen Xia
- State Key Laboratory of Virology and Hubei Province Key Laboratory of Allergy and ImmunologyInstitute of Medical VirologySchool of Basic Medical SciencesWuhan UniversityWuhanHubei430072China
| | - Zhuanchang Wu
- Key Laboratory for Experimental Teratology of Ministry of Education and Department of ImmunologySchool of Basic Medical SciencesCheeloo Medical CollegeShandong UniversityJinanShandong250012China
| | - Chunhong Ma
- Key Laboratory for Experimental Teratology of Ministry of Education and Department of ImmunologySchool of Basic Medical SciencesCheeloo Medical CollegeShandong UniversityJinanShandong250012China
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10
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Abstract
Hepatitis B virus (HBV) is a hepatotropic virus and an important human pathogen. There are an estimated 296 million people in the world that are chronically infected by this virus, and many of them will develop severe liver diseases including hepatitis, cirrhosis and hepatocellular carcinoma (HCC). HBV is a small DNA virus that replicates via the reverse transcription pathway. In this review, we summarize the molecular pathways that govern the replication of HBV and its interactions with host cells. We also discuss viral and non-viral factors that are associated with HBV-induced carcinogenesis and pathogenesis, as well as the role of host immune responses in HBV persistence and liver pathogenesis.
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Affiliation(s)
- Yu-Chen Chuang
- Department of Molecular Microbiology and Immunology, University of Southern California Keck School of Medicine, Los Angeles, CA 90089, USA
| | - Kuen-Nan Tsai
- Department of Molecular Microbiology and Immunology, University of Southern California Keck School of Medicine, Los Angeles, CA 90089, USA
| | - Jing-Hsiung James Ou
- Department of Molecular Microbiology and Immunology, University of Southern California Keck School of Medicine, Los Angeles, CA 90089, USA
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11
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Xu F, Song H, Xiao Q, Wei Q, Pang X, Gao Y, Tan G. Type-III interferon stimulated gene TRIM31 mutation in an HBV patient blocks its ability in promoting HBx degradation. Virus Res 2022; 308:198650. [PMID: 34863820 DOI: 10.1016/j.virusres.2021.198650] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2021] [Revised: 11/29/2021] [Accepted: 11/29/2021] [Indexed: 10/19/2022]
Abstract
TRIM5γ, together with TRIM31, has been shown to promote HBx ubiquitination and degradation. This study aimed to explore whether a patient with HCC (hepatic cell carcinoma) having a small nucleotide inserted into the TRIM31 gene, which made a shorter transcript stop at 768 bp, would result in blocking the activity of TRIM31 in promoting HBx degradation. Besides, this study aimed to determine the binding region of the TRIM31-TRIM5γ-HBx complex. HBV (Hepatitis B virus) infection was reported to induce type-III IFN but not type-I or type-II IFNs, here TRIM31 was found to be a type III rather than a type I stimulated gene, which was indispensable in inhibiting the hepatitis B virus replication by the interferon families. Thus, this study further identified the critical role of TRIM31 in the host-hepatitis B virus interaction.
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Affiliation(s)
- Fengchao Xu
- Department of Immunology, Institute of Translational Medicine, the First Hospital of Jilin University, Changchun, Jilin 130061, China
| | - Hongxiao Song
- Department of Immunology, Institute of Translational Medicine, the First Hospital of Jilin University, Changchun, Jilin 130061, China
| | - Qingfei Xiao
- Department of Nephrology, the First Hospital of Jilin University, Changchun, 130031, Jilin, China
| | - Qi Wei
- Department of Anesthesia, the First Hospital, Jilin University, Changchun, 130021, Jilin, China
| | - Xiaoli Pang
- Department of Pediatric Gastroenterology, the First Hospital, Jilin University, Changchun 130021, Jilin, China
| | - Yanli Gao
- Department of Pediatrics, the First Hospital, Jilin University, Changchun 130021, Jilin, China.
| | - Guangyun Tan
- Department of Immunology, Institute of Translational Medicine, the First Hospital of Jilin University, Changchun, Jilin 130061, China.
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12
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Tsuge M. The association between hepatocarcinogenesis and intracellular alterations due to hepatitis B virus infection. Liver Int 2021; 41:2836-2848. [PMID: 34559952 DOI: 10.1111/liv.15065] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/24/2021] [Revised: 09/13/2021] [Accepted: 09/19/2021] [Indexed: 02/06/2023]
Abstract
Chronic hepatitis B virus (HBV) infection is a worldwide health problem leading to severe liver dysfunction, including liver cirrhosis and hepatocellular carcinoma. Although current antiviral therapies for chronic HBV infection have been improved and can lead to a strong suppression of viral replication, it is difficult to completely eliminate the virus with these therapies once chronic HBV infection is established in the host. Furthermore, chronic HBV infection alters intracellular metabolism and signalling pathways, resulting in the activation of carcinogenesis in the liver. HBV produces four viral proteins: hepatitis B surface-, hepatitis B core-, hepatitis B x protein, and polymerase; each plays an important role in HBV replication and the intracellular signalling pathways associated with hepatocarcinogenesis. In vitro and in vivo experimental models for analyzing HBV infection and replication have been established, and gene expression analyses using microarrays or next-generation sequencing have also been developed. Thus, it is possible to clarify the molecular mechanisms for intracellular alterations, such as endoplasmic reticulum stress, oxidative stress, and epigenetic modifications. In this review, the impact of HBV viral proteins and intracellular alterations in HBV-associated hepatocarcinogenesis are discussed.
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Affiliation(s)
- Masataka Tsuge
- Natural Science Center for Basic Research and Development, Hiroshima University, Hiroshima, Japan.,Department of Gastroenterology and Metabolism, Graduate School of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan.,Research Center for Hepatology and Gastroenterology, Hiroshima University, Hiroshima, Japan
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13
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Erken R, Andre P, Roy E, Kootstra N, Barzic N, Girma H, Laveille C, Radreau‐Pierini P, Darteil R, Vonderscher J, Scalfaro P, Tangkijvanich P, Flisiak R, Reesink H. Farnesoid X receptor agonist for the treatment of chronic hepatitis B: A safety study. J Viral Hepat 2021; 28:1690-1698. [PMID: 34467593 PMCID: PMC9293351 DOI: 10.1111/jvh.13608] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/07/2021] [Accepted: 08/17/2021] [Indexed: 12/09/2022]
Abstract
The nuclear farnesoid X receptor (FXR) regulates bile acid homeostasis and is a drug target for metabolic liver diseases. FXR also plays an important role in hepatitis B virus (HBV) DNA transcription. In vitro and in mice, FXR agonist treatment leads to inhibition of viral replication and a decline in viral proteins, pregenomic RNA (pgRNA) and HBV DNA levels. We aimed to translate this to a clinical use by primarily evaluating the safety and secondary the anti-viral effect of Vonafexor, a FXR agonist, in chronic hepatitis B (CHB) patients. In total, 73 CHB patients were enrolled in a two-part Phase Ib double-blind, placebo-controlled trial. Patients were randomized to receive oral Vonafexor (100, 200 and 400 mg once daily, or 200 mg twice daily), placebo, or entecavir (Part A, n = 48) or to receive Vonafexor (300 mg once daily or 150 mg twice daily), or placebo, combined with pegylated-interferon-α2a (Part B, n = 25) for 29 days. Patients were followed up for 35 days. Enrolled CHB patients were mostly HBeAg-negative. Vonafexor was overall well tolerated and safe. The most frequent adverse events were moderate gastrointestinal events. Pruritus was more frequent with twice-daily compared with once-daily regimens (56%-67% vs. 16%, respectively, p < 0.05). Vonafexor monotherapy of 400 mg once daily decreased HBsAg concentrations (-0.1 log10 IU/mL, p < 0.05), and Vonafexor/pegylated-IFN-α2a combination therapy decreased HBcrAg and pgRNA. In conclusion, Vonafexor was safe with a decline in HBV markers observed in CHB patients suggesting a potential anti-viral effect the therapeutic potential of which has to be evaluated in larger trials.
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Affiliation(s)
- Robin Erken
- Department of Gastroenterology and HepatologyAmsterdam UMCUniversity of AmsterdamDuivendrechtThe Netherlands
| | - Patrice Andre
- Inserm U1111CNRS UMR5308Université Lyon 1, and Ecole Normale Supérieure de LyonLyonFrance
| | | | - Neeltje Kootstra
- Amsterdam UMCUniversity of AmsterdamDepartment of Experimental ImmunologyAmsterdam Infection & Immunity InstituteUniversity of AmsterdamAmsterdamNetherlands
| | | | | | | | | | | | | | | | - Pisit Tangkijvanich
- Center of Excellence in Hepatitis and Liver CancerFaculty of MedicineChulalongkorn UniversityBangkokThailand
| | - Robert Flisiak
- Klinika Chorób Zakaźnych I Hepatologii UMBUniwersytecki Szpital Kliniczny w BiałymstokuBiałystokPoland
| | - Henk Reesink
- Department of Gastroenterology and HepatologyLeiden University Medical CenterLeidenThe Netherlands
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14
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Medhat A, Arzumanyan A, Feitelson MA. Hepatitis B x antigen (HBx) is an important therapeutic target in the pathogenesis of hepatocellular carcinoma. Oncotarget 2021; 12:2421-2433. [PMID: 34853663 PMCID: PMC8629409 DOI: 10.18632/oncotarget.28077] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2021] [Accepted: 09/04/2021] [Indexed: 12/12/2022] Open
Abstract
Hepatitis B virus (HBV) is a human pathogen that has infected an estimated two billion people worldwide. Despite the availability of highly efficacious vaccines, universal screening of the blood supply for virus, and potent direct acting anti-viral drugs, there are more than 250 million carriers of HBV who are at risk for the sequential development of hepatitis, fibrosis, cirrhosis and hepatocellular carcinoma (HCC). More than 800,000 deaths per year are attributed to chronic hepatitis B. Many different therapeutic approaches have been developed to block virus replication, and although effective, none are curative. These treatments have little or no impact upon the portions of integrated HBV DNA, which often encode the virus regulatory protein, HBx. Although given little attention, HBx is an important therapeutic target because it contributes importantly to (a) HBV replication, (b) in protecting infected cells from immune mediated destruction during chronic infection, and (c) in the development of HCC. Thus, the development of therapies targeting HBx, combined with other established therapies, will provide a functional cure that will target virus replication and further reduce or eliminate both the morbidity and mortality associated with chronic liver disease and HCC. Simultaneous targeting of all these characteristics underscores the importance of developing therapies against HBx.
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Affiliation(s)
- Arvin Medhat
- Department of Molecular Cell Biology, Azad University, North Unit, Tehran, Iran
| | - Alla Arzumanyan
- Department of Biology, College of Science and Technology, Temple University, Philadelphia, PA, USA
| | - Mark A Feitelson
- Department of Biology, College of Science and Technology, Temple University, Philadelphia, PA, USA
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15
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Canonical and Divergent N-Terminal HBx Isoform Proteins Unveiled: Characteristics and Roles during HBV Replication. Biomedicines 2021; 9:biomedicines9111701. [PMID: 34829930 PMCID: PMC8616016 DOI: 10.3390/biomedicines9111701] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2021] [Revised: 11/11/2021] [Accepted: 11/11/2021] [Indexed: 11/16/2022] Open
Abstract
Hepatitis B virus (HBV) X protein (HBx) is a viral regulatory and multifunctional protein. It is well-known that the canonical HBx reading frame bears two phylogenetically conserved internal in-frame translational initiation codons at Met2 and Met3, thus possibly generating divergent N-terminal smaller isoforms during translation. Here, we demonstrate that the three distinct HBx isoforms are generated from the ectopically expressed HBV HBx gene, named XF (full-length), XM (medium-length), and XS (short-length); they display different subcellular localizations when expressed individually in cultured hepatoma cells. Particularly, the smallest HBx isoform, XS, displayed a predominantly cytoplasmic localization. To study HBx proteins during viral replication, we performed site-directed mutagenesis to target the individual or combinatorial expression of the HBx isoforms within the HBV viral backbone (full viral genome). Our results indicate that of all HBx isoforms, only the smallest HBx isoform, XS, can restore WT levels of HBV replication, and bind to the viral mini chromosome, thereby establishing an active chromatin state, highlighting its crucial activities during HBV replication. Intriguingly, we found that sequences of HBV HBx genotype H are devoid of the conserved Met3 position, and therefore HBV genotype H infection is naturally silent for the expression of the HBx XS isoform. Finally, we found that the HBx XM (medium-length) isoform shares significant sequence similarity with the N-terminus domain of the COMMD8 protein, a member of the copper metabolism MURR1 domain-containing (COMMD) protein family. This novel finding might facilitate studies on the phylogenetic origin of the HBV X protein. The identification and functional characterization of its isoforms will shift the paradigm by changing the concept of HBx from being a unique, canonical, and multifunctional protein toward the occurrence of different HBx isoforms, carrying out different overlapping functions at different subcellular localizations during HBV genome replication. Significantly, our current work unveils new crucial HBV targets to study for potential antiviral research, and human virus pathogenesis.
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16
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Yuan H, Zhao L, Yuan Y, Yun H, Zheng W, Geng Y, Yang G, Wang Y, Zhao M, Zhang X. HBx represses WDR77 to enhance HBV replication by DDB1-mediated WDR77 degradation in the liver. Am J Cancer Res 2021; 11:8362-8378. [PMID: 34373747 PMCID: PMC8343998 DOI: 10.7150/thno.57531] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2020] [Accepted: 07/06/2021] [Indexed: 12/18/2022] Open
Abstract
Rationale: Hepatitis B x protein (HBx) is required to initiate and maintain the replication of hepatitis B virus (HBV). Protein arginine methyltransferases 5 (PRMT5) negatively regulates HBV transcription. WD repeat domain 77 protein (WDR77) greatly enhances the methyltransferase activity of PRMT5. However, the role of WDR77 in the modulation of cccDNA transcription and HBV replication is poorly understood. In this study, we investigated the mechanism by which HBx modulated HBV replication involving WDR77 in the liver. Methods: A human liver-chimeric mouse model was established. Immunohistochemistry (IHC) staining, Western blot analysis, Southern blot analysis, Northern blot analysis, immunofluorescence assays, ELISA, RT-qPCR, CoIP assays, and ChIP assays were performed in human liver-chimeric mouse model, primary human hepatocytes (PHHs), HepG2-NTCP, dHepaRG and HepG2 cell lines. Results: HBV infection and HBx expression remarkably reduced the protein levels of WDR77 in human liver-chimeric mice and HepG2-NTCP cells. WDR77 restricted cccDNA transcription and HBV replication in PHHs and HepG2-NTCP cells. Mechanically, WDR77 enhanced PRMT5-triggered symmetric dimethylation of arginine 3 on H4 (H4R3me2s) on the cccDNA minichromosome to control cccDNA transcription. HBx drove the cellular DDB1-containing E3 ubiquitin ligase to degrade WDR77 through recruiting WDR77, leading to the disability of methyltransferase activity of PRMT5. Thus, HBx promoted HBV replication by driving a positive feedback loop of HBx-DDB1/WDR77/PRMT5/H4R3me2s/cccDNA/HBV/HBx in the liver. Conclusions: HBx attenuates the WDR77-mediated HBV repression by driving DDB1-induced WDR77 degradation in the liver. Our finding provides new insights into the mechanism by which HBx enhances HBV replication in the liver.
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17
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Song Y, Li M, Wang Y, Zhang H, Wei L, Xu W. E3 ubiquitin ligase TRIM21 restricts hepatitis B virus replication by targeting HBx for proteasomal degradation. Antiviral Res 2021; 192:105107. [PMID: 34097931 DOI: 10.1016/j.antiviral.2021.105107] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2020] [Revised: 04/29/2021] [Accepted: 05/31/2021] [Indexed: 12/13/2022]
Abstract
As a cytosol ubiquitin ligase and antibody receptor, Tripartite motif-containing 21 (TRIM21) has been reported to mediate the restriction of hepatitis B virus (HBV) through an HBx-antibody-dependent intracellular neutralization (ADIN) mechanism. However, whether TRIM21 limits HBV replication by targeting viral proteins remains unclarified. In this study, we demonstrate that TRIM21 inhibits HBV gene transcription and replication in HBV plasmid transfected and HBV-infected hepatoma cells. RING and PRY-SPRY domains are involved in this activity. TRIM21 interacts with HBx protein and targets HBx for ubiquitination and proteasomal degradation, leading to impaired HBx-mediated degradation of structural maintenance of chromosomes 6 (Smc6) and suppression of HBV replication. TRIM21 fails to restrict the replication of an HBx-deficient HBV. And knock-down of Smc6 largely impairs the anti-HBV activity of TRIM21 in HepG2 cells. In a hydrodynamic injection (HDI)-based HBV mouse model, we confirm an in vivo anti-HBV and anti-HBx therapeutic effect of TRIM21 by over-expression or knocking-out strategy. Our findings reveal a novel mechanism that TRIM21 restricts HBV replication through targeting HBx-Smc5/6 pathway, which may have an implication in the future TRIM21-based therapeutic application.
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Affiliation(s)
- Yahui Song
- 199 RengAi Road, Institute of Biology and Medical Sciences, Soochow University, Suzhou 215123, P.R. China
| | - Min Li
- 199 RengAi Road, Institute of Biology and Medical Sciences, Soochow University, Suzhou 215123, P.R. China
| | - Yanqi Wang
- 199 RengAi Road, Institute of Biology and Medical Sciences, Soochow University, Suzhou 215123, P.R. China
| | - Hongkai Zhang
- 199 RengAi Road, Institute of Biology and Medical Sciences, Soochow University, Suzhou 215123, P.R. China
| | - Lin Wei
- 199 RengAi Road, Institute of Biology and Medical Sciences, Soochow University, Suzhou 215123, P.R. China
| | - Wei Xu
- 199 RengAi Road, Institute of Biology and Medical Sciences, Soochow University, Suzhou 215123, P.R. China.
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18
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Singh P, Kairuz D, Arbuthnot P, Bloom K. Silencing hepatitis B virus covalently closed circular DNA: The potential of an epigenetic therapy approach. World J Gastroenterol 2021; 27:3182-3207. [PMID: 34163105 PMCID: PMC8218364 DOI: 10.3748/wjg.v27.i23.3182] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/29/2021] [Revised: 03/23/2021] [Accepted: 05/07/2021] [Indexed: 02/06/2023] Open
Abstract
Global prophylactic vaccination programmes have helped to curb new hepatitis B virus (HBV) infections. However, it is estimated that nearly 300 million people are chronically infected and have a high risk of developing hepatocellular carcinoma. As such, HBV remains a serious health priority and the development of novel curative therapeutics is urgently needed. Chronic HBV infection has been attributed to the persistence of the covalently closed circular DNA (cccDNA) which establishes itself as a minichromosome in the nucleus of hepatocytes. As the viral transcription intermediate, the cccDNA is responsible for producing new virions and perpetuating infection. HBV is dependent on various host factors for cccDNA formation and the minichromosome is amenable to epigenetic modifications. Two HBV proteins, X (HBx) and core (HBc) promote viral replication by modulating the cccDNA epigenome and regulating host cell responses. This includes viral and host gene expression, chromatin remodeling, DNA methylation, the antiviral immune response, apoptosis, and ubiquitination. Elimination of the cccDNA minichromosome would result in a sterilizing cure; however, this may be difficult to achieve. Epigenetic therapies could permanently silence the cccDNA minichromosome and promote a functional cure. This review explores the cccDNA epigenome, how host and viral factors influence transcription, and the recent epigenetic therapies and epigenome engineering approaches that have been described.
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Affiliation(s)
- Prashika Singh
- Wits/SAMRC Antiviral Gene Therapy Research Unit, School of Pathology, University of the Witwatersrand, Johannesburg 2050, Gauteng, South Africa
| | - Dylan Kairuz
- Wits/SAMRC Antiviral Gene Therapy Research Unit, School of Pathology, University of the Witwatersrand, Johannesburg 2050, Gauteng, South Africa
| | - Patrick Arbuthnot
- Wits/SAMRC Antiviral Gene Therapy Research Unit, School of Pathology, University of the Witwatersrand, Johannesburg 2050, Gauteng, South Africa
| | - Kristie Bloom
- Wits/SAMRC Antiviral Gene Therapy Research Unit, School of Pathology, University of the Witwatersrand, Johannesburg 2050, Gauteng, South Africa
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19
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Tang D, Zhao H, Wu Y, Peng B, Gao Z, Sun Y, Duan J, Qi Y, Li Y, Zhou Z, Guo G, Zhang Y, Li C, Sui J, Li W. Transcriptionally inactive hepatitis B virus episome DNA preferentially resides in the vicinity of chromosome 19 in 3D host genome upon infection. Cell Rep 2021; 35:109288. [PMID: 34192543 DOI: 10.1016/j.celrep.2021.109288] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2020] [Revised: 03/07/2021] [Accepted: 06/02/2021] [Indexed: 12/12/2022] Open
Abstract
The hepatitis B virus (HBV) infects 257 million people worldwide. HBV infection requires establishment and persistence of covalently closed circular (ccc) DNA, a viral episome, in nucleus. Here, we study cccDNA spatial localization in the 3D host genome by using chromosome conformation capture-based sequencing analysis and fluorescence in situ hybridization (FISH). We show that transcriptionally inactive cccDNA is not randomly distributed in host nucleus. Rather, it is preferentially accumulated at specialized areas, including regions close to chromosome 19 (chr.19). Activation of the cccDNA is apparently associated with its re-localization, from a pre-established heterochromatin hub formed by 5 regions of chr.19 to transcriptionally active regions formed by chr.19 and nearby chromosomes including chr.16, 17, 20, and 22. This active versus inactive positioning at discrete regions of the host genome is primarily controlled by the viral HBx protein and by host factors including the structural maintenance of chromosomes protein 5/6 (SMC5/6) complex.
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Affiliation(s)
- Dingbin Tang
- Peking University-Tsinghua University-National Institute of Biological Sciences Joint Graduate Program, School of Life Sciences, Peking University, Beijing, China; National Institute of Biological Sciences, Beijing, China
| | - Hanqing Zhao
- National Institute of Biological Sciences, Beijing, China
| | - Yumeng Wu
- Peking University-Tsinghua University-National Institute of Biological Sciences Joint Graduate Program, School of Life Sciences, Peking University, Beijing, China; National Institute of Biological Sciences, Beijing, China
| | - Bo Peng
- Peking University-Tsinghua University-National Institute of Biological Sciences Joint Graduate Program, School of Life Sciences, Peking University, Beijing, China; National Institute of Biological Sciences, Beijing, China
| | - Zhenchao Gao
- National Institute of Biological Sciences, Beijing, China
| | - Yinyan Sun
- National Institute of Biological Sciences, Beijing, China
| | - Jinzhi Duan
- National Institute of Biological Sciences, Beijing, China
| | - Yonghe Qi
- National Institute of Biological Sciences, Beijing, China
| | - Yunfei Li
- National Institute of Biological Sciences, Beijing, China
| | - Zhongmin Zhou
- College of Life Sciences, Beijing Normal University, Beijing, China; National Institute of Biological Sciences, Beijing, China
| | - Guilan Guo
- College of Life Sciences, Beijing Normal University, Beijing, China; National Institute of Biological Sciences, Beijing, China
| | - Yu Zhang
- National Institute of Biological Sciences, Beijing, China
| | - Cheng Li
- School of Life Sciences, Center for Statistical Science, Center for Bioinformatics, Peking University, Beijing, China
| | - Jianhua Sui
- National Institute of Biological Sciences, Beijing, China; Tsinghua Institute of Multidisciplinary Biomedical Research, Tsinghua University, Beijing, China
| | - Wenhui Li
- National Institute of Biological Sciences, Beijing, China; Tsinghua Institute of Multidisciplinary Biomedical Research, Tsinghua University, Beijing, China.
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20
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Mena EL, Donahue CJ, Vaites LP, Li J, Rona G, O'Leary C, Lignitto L, Miwatani-Minter B, Paulo JA, Dhabaria A, Ueberheide B, Gygi SP, Pagano M, Harper JW, Davey RA, Elledge SJ. ORF10-Cullin-2-ZYG11B complex is not required for SARS-CoV-2 infection. Proc Natl Acad Sci U S A 2021; 118:e2023157118. [PMID: 33827988 PMCID: PMC8092598 DOI: 10.1073/pnas.2023157118] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
In order to understand the transmission and virulence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), it is necessary to understand the functions of each of the gene products encoded in the viral genome. One feature of the SARS-CoV-2 genome that is not present in related, common coronaviruses is ORF10, a putative 38-amino acid protein-coding gene. Proteomic studies found that ORF10 binds to an E3 ubiquitin ligase containing Cullin-2, Rbx1, Elongin B, Elongin C, and ZYG11B (CRL2ZYG11B). Since CRL2ZYG11B mediates protein degradation, one possible role for ORF10 is to "hijack" CRL2ZYG11B in order to target cellular, antiviral proteins for ubiquitylation and subsequent proteasomal degradation. Here, we investigated whether ORF10 hijacks CRL2ZYG11B or functions in other ways, for example, as an inhibitor or substrate of CRL2ZYG11B While we confirm the ORF10-ZYG11B interaction and show that the N terminus of ORF10 is critical for it, we find no evidence that ORF10 is functioning to inhibit or hijack CRL2ZYG11B Furthermore, ZYG11B and its paralog ZER1 are dispensable for SARS-CoV-2 infection in cultured cells. We conclude that the interaction between ORF10 and CRL2ZYG11B is not relevant for SARS-CoV-2 infection in vitro.
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Affiliation(s)
- Elijah L Mena
- Division of Genetics, Department of Genetics, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115
- Howard Hughes Medical Institute, Brigham and Women's Hospital, Boston, MA 02115
| | - Callie J Donahue
- Department of Microbiology, National Emerging Infectious Disease Laboratories, Boston University Medical Campus, Boston, MA 02118
| | - Laura Pontano Vaites
- Department of Cell Biology, Blavatnik Institute, Harvard Medical School, Boston, MA 02115
| | - Jie Li
- Department of Biochemistry and Molecular Pharmacology, New York University Grossman School of Medicine, New York, NY 10016
| | - Gergely Rona
- Department of Biochemistry and Molecular Pharmacology, New York University Grossman School of Medicine, New York, NY 10016
- Howard Hughes Medical Institute, New York University Grossman School of Medicine, New York, NY 10016
| | - Colin O'Leary
- Division of Genetics, Department of Genetics, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115
| | - Luca Lignitto
- Department of Biochemistry and Molecular Pharmacology, New York University Grossman School of Medicine, New York, NY 10016
| | - Bearach Miwatani-Minter
- Department of Biochemistry and Molecular Pharmacology, New York University Grossman School of Medicine, New York, NY 10016
| | - Joao A Paulo
- Department of Cell Biology, Blavatnik Institute, Harvard Medical School, Boston, MA 02115
| | - Avantika Dhabaria
- Department of Biochemistry and Molecular Pharmacology, New York University Grossman School of Medicine, New York, NY 10016
- Proteomics Laboratory, Division of Advanced Research Technologies, New York University Grossman School of Medicine, New York, NY 10016
| | - Beatrix Ueberheide
- Department of Biochemistry and Molecular Pharmacology, New York University Grossman School of Medicine, New York, NY 10016
- Proteomics Laboratory, Division of Advanced Research Technologies, New York University Grossman School of Medicine, New York, NY 10016
- Department of Neurology, New York University Grossman School of Medicine, New York, NY 10016
| | - Steven P Gygi
- Department of Cell Biology, Blavatnik Institute, Harvard Medical School, Boston, MA 02115
| | - Michele Pagano
- Department of Biochemistry and Molecular Pharmacology, New York University Grossman School of Medicine, New York, NY 10016;
- Howard Hughes Medical Institute, New York University Grossman School of Medicine, New York, NY 10016
| | - J Wade Harper
- Department of Cell Biology, Blavatnik Institute, Harvard Medical School, Boston, MA 02115;
| | - Robert A Davey
- Department of Microbiology, National Emerging Infectious Disease Laboratories, Boston University Medical Campus, Boston, MA 02118;
| | - Stephen J Elledge
- Division of Genetics, Department of Genetics, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115;
- Howard Hughes Medical Institute, Brigham and Women's Hospital, Boston, MA 02115
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21
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Takeuchi Y, Tsuge M, Tsushima K, Suehiro Y, Fujino H, Ono A, Yamauchi M, Makokha GN, Nakahara T, Murakami E, Abe-Chayama H, Kawaoka T, Miki D, Imamura M, Aikata H, Hayes CN, Tateno C, Chayama K. Signal Activation of Hepatitis B Virus-Related Hepatocarcinogenesis by Up-regulation of SUV39h1. J Infect Dis 2021; 222:2061-2070. [PMID: 32514521 DOI: 10.1093/infdis/jiaa317] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2020] [Accepted: 06/06/2020] [Indexed: 12/22/2022] Open
Abstract
BACKGROUND Hepatitis B virus (HBV) X (HBx) protein is associated with hepatocellular carcinogenesis via the induction of malignant transformation and mitochondrial dysfunction. However, the association between HBx and histone methyltransferase in carcinogenesis has not been fully clarified. In the current study, we analyzed the association between HBx and the histone methyltransferase suppressor of variegation 3-9 homolog 1 (SUV39h1) using HBV replication models. METHODS We constructed several HBx and SUV39h1 expression plasmids and analyzed the association between HBx and SUV39h1 with respect to HBV replication and hepatocarcinogenesis. RESULTS SUV39h1 up-regulation was observed in HBV-infected humanized mouse livers and clinical HBV-related hepatocellular carcinoma tissues, indicating that SUV39h1 expression might be regulated by HBV infection. Through in vitro analysis, we determined that the coactivator domain of HBx interacts with the PSET (PostSET) and SET (Su(var)3-9, Enhancer-of-zeste, Trithorax) domains of SUV39h1. The expression levels of 4 genes, activating transcription factor 6, α-fetoprotein, growth arrest and DNA damage-inducible 45a, and dual-specificity phosphatase 1, known to induce carcinogenesis via HBx expression, were up-regulated by HBx and further up-regulated in the presence of both HBx and SUV39h1. Furthermore, histone methyltransferase activity, the main function of SUV39h1, was enhanced in the presence of HBx. CONCLUSIONS We demonstrated that SUV39h1 and HBx enhance each other's activity, leading to HBx-mediated hepatocarcinogenesis. We propose that regulation of this interaction could help suppress development of hepatocellular carcinoma.
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Affiliation(s)
- Yasue Takeuchi
- Department of Gastroenterology and Metabolism, Graduate School of Biomedical & Health Sciences, Hiroshima University, Hiroshima, Japan.,Research Center for Hepatology and Gastroenterology, Hiroshima University, Hiroshima, Japan
| | - Masataka Tsuge
- Department of Gastroenterology and Metabolism, Graduate School of Biomedical & Health Sciences, Hiroshima University, Hiroshima, Japan.,Research Center for Hepatology and Gastroenterology, Hiroshima University, Hiroshima, Japan.,Natural Science Center for Basic Research and Development, Hiroshima University, Hiroshima, Japan
| | - Ken Tsushima
- Department of Gastroenterology and Metabolism, Graduate School of Biomedical & Health Sciences, Hiroshima University, Hiroshima, Japan.,Research Center for Hepatology and Gastroenterology, Hiroshima University, Hiroshima, Japan
| | - Yosuke Suehiro
- Department of Gastroenterology and Metabolism, Graduate School of Biomedical & Health Sciences, Hiroshima University, Hiroshima, Japan.,Research Center for Hepatology and Gastroenterology, Hiroshima University, Hiroshima, Japan
| | - Hatsue Fujino
- Department of Gastroenterology and Metabolism, Graduate School of Biomedical & Health Sciences, Hiroshima University, Hiroshima, Japan.,Research Center for Hepatology and Gastroenterology, Hiroshima University, Hiroshima, Japan
| | - Atsushi Ono
- Department of Gastroenterology and Metabolism, Graduate School of Biomedical & Health Sciences, Hiroshima University, Hiroshima, Japan.,Research Center for Hepatology and Gastroenterology, Hiroshima University, Hiroshima, Japan
| | - Masami Yamauchi
- Department of Gastroenterology and Metabolism, Graduate School of Biomedical & Health Sciences, Hiroshima University, Hiroshima, Japan.,Research Center for Hepatology and Gastroenterology, Hiroshima University, Hiroshima, Japan
| | - Grace Naswa Makokha
- Department of Gastroenterology and Metabolism, Graduate School of Biomedical & Health Sciences, Hiroshima University, Hiroshima, Japan.,Research Center for Hepatology and Gastroenterology, Hiroshima University, Hiroshima, Japan
| | - Takashi Nakahara
- Department of Gastroenterology and Metabolism, Graduate School of Biomedical & Health Sciences, Hiroshima University, Hiroshima, Japan.,Research Center for Hepatology and Gastroenterology, Hiroshima University, Hiroshima, Japan
| | - Eisuke Murakami
- Department of Gastroenterology and Metabolism, Graduate School of Biomedical & Health Sciences, Hiroshima University, Hiroshima, Japan.,Research Center for Hepatology and Gastroenterology, Hiroshima University, Hiroshima, Japan
| | - Hiromi Abe-Chayama
- Research Center for Hepatology and Gastroenterology, Hiroshima University, Hiroshima, Japan.,Center for Medical Specialist Graduate Education and Research, Institute of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan
| | - Tomokazu Kawaoka
- Department of Gastroenterology and Metabolism, Graduate School of Biomedical & Health Sciences, Hiroshima University, Hiroshima, Japan.,Research Center for Hepatology and Gastroenterology, Hiroshima University, Hiroshima, Japan
| | - Daiki Miki
- Department of Gastroenterology and Metabolism, Graduate School of Biomedical & Health Sciences, Hiroshima University, Hiroshima, Japan.,Research Center for Hepatology and Gastroenterology, Hiroshima University, Hiroshima, Japan
| | - Michio Imamura
- Department of Gastroenterology and Metabolism, Graduate School of Biomedical & Health Sciences, Hiroshima University, Hiroshima, Japan.,Research Center for Hepatology and Gastroenterology, Hiroshima University, Hiroshima, Japan
| | - Hiroshi Aikata
- Department of Gastroenterology and Metabolism, Graduate School of Biomedical & Health Sciences, Hiroshima University, Hiroshima, Japan.,Research Center for Hepatology and Gastroenterology, Hiroshima University, Hiroshima, Japan
| | - C Nelson Hayes
- Department of Gastroenterology and Metabolism, Graduate School of Biomedical & Health Sciences, Hiroshima University, Hiroshima, Japan.,Research Center for Hepatology and Gastroenterology, Hiroshima University, Hiroshima, Japan
| | - Chise Tateno
- Research Center for Hepatology and Gastroenterology, Hiroshima University, Hiroshima, Japan.,PhoenixBio, Higashi-Hiroshima, Japan
| | - Kazuaki Chayama
- Department of Gastroenterology and Metabolism, Graduate School of Biomedical & Health Sciences, Hiroshima University, Hiroshima, Japan.,Research Center for Hepatology and Gastroenterology, Hiroshima University, Hiroshima, Japan.,Laboratory for Digestive Diseases, RIKEN Center for Integrative Medical Sciences, Hiroshima, Japan
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22
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Omagari K, Asamitsu K, Tanaka Y. Application of fluorescent-based technology detecting protein-protein interactions to monitor the binding of hepatitis B virus X protein to DNA-damage-binding protein 1. Biophys Physicobiol 2021; 18:67-77. [PMID: 33977004 PMCID: PMC8056151 DOI: 10.2142/biophysico.bppb-v18.008] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2020] [Accepted: 03/12/2021] [Indexed: 12/02/2022] Open
Abstract
The hepatitis B virus X protein (HBx) and the V protein of paramyxovirus simian virus 5 (SV5-V) interact with DNA damage-binding protein 1 (DDB1), a cellular enzyme involved in DNA repair and cell cycle regulation, to stimulate viral activity. DDB1 has several cellular substrates, and the amino acid sequences of the binding sites in the viral proteins and their substrates are notably dissimilar. To determine whether HBx binds preferentially to DDB1, despite differences in the amino acid sequences, we developed a system to monitor DDB1 binding in living cells through a protein-protein visualization system, designated fluorescent-based technology detecting protein-protein interactions (Fluoppi). HBx in association with DDB1 formed clear fluorescent puncta. The number of these fluorescent puncta increased with an increase in the amount of HBx. The binding of HBx to DDB1 inhibited the cellular substrate DDB1-CUL4A-associated factor 9 (DCAF9) from binding to DDB1. The inhibitor nitazoxanide prevented the viral proteins HBx and SV5-V from binding to DDB1 but did not inhibit the binding of DCAF9 or HBx(ΔNC), which constitutes the binding site of HBx. Our results demonstrate that the Fluoppi system is useful for monitoring the binding of HBx to DDB1 as well as for examining the effect of drugs on DDB1-Hbx binding.
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Affiliation(s)
- Katsumi Omagari
- Department of Virology, Nagoya City University Graduate School of Medical Sciences, Nagoya, Aichi 467-8601, Japan
| | - Kaori Asamitsu
- Department of Neurocognitive Science, Nagoya City University Graduate School of Medical Sciences, Nagoya, Aichi 467-8601, Japan
| | - Yasuhito Tanaka
- Department of Virology, Nagoya City University Graduate School of Medical Sciences, Nagoya, Aichi 467-8601, Japan.,Department of Gastroenterology and Hepatology, Faculty of Life Sciences, Kumamoto University, Kumamoto 860-8556, Japan
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23
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Dicoumarol, an NQO1 inhibitor, blocks cccDNA transcription by promoting degradation of HBx. J Hepatol 2021; 74:522-534. [PMID: 32987030 DOI: 10.1016/j.jhep.2020.09.019] [Citation(s) in RCA: 65] [Impact Index Per Article: 21.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/27/2020] [Revised: 09/06/2020] [Accepted: 09/14/2020] [Indexed: 12/16/2022]
Abstract
BACKGROUND & AIMS Current antiviral therapies help keep HBV under control, but they are not curative, as they are unable to eliminate the intracellular viral replication intermediate termed covalently closed circular DNA (cccDNA). Therefore, there remains an urgent need to develop strategies to cure CHB. Functional silencing of cccDNA is a crucial curative strategy that may be achieved by targeting the viral protein HBx. METHODS We screened 2,000 small-molecule compounds for their ability to inhibit HiBiT-tagged HBx (HiBiT-HBx) expression by using a HiBiT lytic detection system. The antiviral activity of a candidate compound and underlying mechanism of its effect on cccDNA transcription were evaluated in HBV-infected cells and a humanised liver mouse model. RESULTS Dicoumarol, an inhibitor of NAD(P)H:quinone oxidoreductase 1 (NQO1), significantly reduced HBx expression. Moreover, dicoumarol showed potent antiviral activity against HBV RNAs, HBV DNA, HBsAg and HBc protein in HBV-infected cells and a humanised liver mouse model. Mechanistic studies demonstrated that endogenous NQO1 binds to and protects HBx protein from 20S proteasome-mediated degradation. NQO1 knockdown or dicoumarol treatment significantly reduced the recruitment of HBx to cccDNA and inhibited the transcriptional activity of cccDNA, which was associated with the establishment of a repressive chromatin state. The absence of HBx markedly blocked the antiviral effect induced by NQO1 knockdown or dicoumarol treatment in HBV-infected cells. CONCLUSIONS Herein, we report on a novel small molecule that targets HBx to combat chronic HBV infection; we also reveal that NQO1 has a role in HBV replication through the regulation of HBx protein stability. LAY SUMMARY Current antiviral therapies for hepatitis B are not curative because of their inability to eliminate covalently closed circular DNA (cccDNA), which persists in the nuclei of infected cells. HBV X (HBx) protein has an important role in regulating cccDNA transcription. Thus, targeting HBx to silence cccDNA transcription could be an important curative strategy. We identified that the small molecule dicoumarol could block cccDNA transcription by promoting HBx degradation; this is a promising therapeutic strategy for the treatment of chronic hepatitis B.
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24
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HBV-Integration Studies in the Clinic: Role in the Natural History of Infection. Viruses 2021; 13:v13030368. [PMID: 33652619 PMCID: PMC7996909 DOI: 10.3390/v13030368] [Citation(s) in RCA: 41] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2021] [Revised: 02/21/2021] [Accepted: 02/22/2021] [Indexed: 02/06/2023] Open
Abstract
Hepatitis B virus (HBV) infection is a major global health problem causing acute and chronic liver disease that can lead to liver cirrhosis and hepatocellular carcinoma (HCC). HBV covalently closed circular DNA (cccDNA) is essential for viral replication and the establishment of a persistent infection. Integrated HBV DNA represents another stable form of viral DNA regularly observed in the livers of infected patients. HBV DNA integration into the host genome occurs early after HBV infection. It is a common occurrence during the HBV life cycle, and it has been detected in all the phases of chronic infection. HBV DNA integration has long been considered to be the main contributor to liver tumorigenesis. The recent development of highly sensitive detection methods and research models has led to the clarification of some molecular and pathogenic aspects of HBV integration. Though HBV integration does not lead to replication-competent transcripts, it can act as a stable source of viral RNA and proteins, which may contribute in determining HBV-specific T-cell exhaustion and favoring virus persistence. The relationship between HBV DNA integration and the immune response in the liver microenvironment might be closely related to the development and progression of HBV-related diseases. While many new antiviral agents aimed at cccDNA elimination or silencing have been developed, integrated HBV DNA remains a difficult therapeutic challenge.
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25
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Guan G, Zheng L, Xi J, Yang X, Chen X, Lu F. Cell Cycle Arrest Protein CDKN2C Is Not an HBV Host Factor. Virol Sin 2021; 36:810-813. [PMID: 33400093 DOI: 10.1007/s12250-020-00337-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2020] [Accepted: 11/16/2020] [Indexed: 12/18/2022] Open
Affiliation(s)
- Guiwen Guan
- Peking University People's Hospital, Peking University Hepatology Institute, Beijing Key Laboratory of Hepatitis C and Immunotherapy for Liver Diseases, Beijing, 100044, China.,Department of Microbiology & Infectious Disease Center, School of Basic Medical Sciences, Peking University Health Science Center, Beijing, 100191, China
| | - Liwei Zheng
- Department of Microbiology & Infectious Disease Center, School of Basic Medical Sciences, Peking University Health Science Center, Beijing, 100191, China
| | - Jingyuan Xi
- Department of Microbiology & Infectious Disease Center, School of Basic Medical Sciences, Peking University Health Science Center, Beijing, 100191, China
| | - Xingwen Yang
- Department of Microbiology & Infectious Disease Center, School of Basic Medical Sciences, Peking University Health Science Center, Beijing, 100191, China
| | - Xiangmei Chen
- Department of Microbiology & Infectious Disease Center, School of Basic Medical Sciences, Peking University Health Science Center, Beijing, 100191, China.
| | - Fengmin Lu
- Peking University People's Hospital, Peking University Hepatology Institute, Beijing Key Laboratory of Hepatitis C and Immunotherapy for Liver Diseases, Beijing, 100044, China. .,Department of Microbiology & Infectious Disease Center, School of Basic Medical Sciences, Peking University Health Science Center, Beijing, 100191, China.
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26
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Yao J, Liang X, Liu Y, Zheng M. Neddylation: A Versatile Pathway Takes on Chronic Liver Diseases. Front Med (Lausanne) 2020; 7:586881. [PMID: 33195347 PMCID: PMC7604315 DOI: 10.3389/fmed.2020.586881] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2020] [Accepted: 08/31/2020] [Indexed: 12/20/2022] Open
Abstract
Neddylation is a ubiquitin-like posttranslational modification that conjugates neural precursor cell expressed developmentally downregulated-8 (Nedd8) to specific substrates for regulation of protein activity. In light of current researches, the neddylation pathway is aberrant in the pathogenesis of many diseases. In our review, we summarize the versatile roles of neddylation in chronic liver diseases (CLDs). CLDs are one of the leading causes of chronic disease-associated deaths worldwide. There are diverse etiologic agents causing CLDs, mainly including hepatitis B virus (HBV) infection, nonalcoholic fatty liver disease (NAFLD), chronic exposure to alcohol or drugs, and autoimmune causes. So far, however, there remains a paucity of effective therapeutic approach to CLDs. In this review, we summarized the role of the neddylation pathway which runs through the chronic hepatitis B/NAFLD-liver fibrosis-cirrhosis-hepatocellular carcinoma (HCC) axis, a canonical pattern in the process of CLD development and progression. The dysregulation of neddylation may provide a better understanding of CLD pathology and even a novel therapeutic strategy. Correspondingly, inhibiting neddylation via MLN4924, a small molecule compound targeting NEDD8-activating enzyme (NAE), can potently alleviate CLD progression and improve the outcome. On this basis, profiling and characterization of the neddylation pathway can provide new insights into the CLD pathology as well as novel therapeutic strategies, independently of the etiology of CLD.
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Affiliation(s)
- Jiping Yao
- The State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, National Clinical Research Center for Infectious Diseases, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, The First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, China
| | - Xue Liang
- The State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, National Clinical Research Center for Infectious Diseases, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, The First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, China
| | - Yanning Liu
- The State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, National Clinical Research Center for Infectious Diseases, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, The First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, China
| | - Min Zheng
- The State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, National Clinical Research Center for Infectious Diseases, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, The First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, China
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27
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Stadelmayer B, Diederichs A, Chapus F, Rivoire M, Neveu G, Alam A, Fraisse L, Carter K, Testoni B, Zoulim F. Full-length 5'RACE identifies all major HBV transcripts in HBV-infected hepatocytes and patient serum. J Hepatol 2020; 73:40-51. [PMID: 32087349 DOI: 10.1016/j.jhep.2020.01.028] [Citation(s) in RCA: 41] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/31/2019] [Revised: 01/10/2020] [Accepted: 01/15/2020] [Indexed: 12/22/2022]
Abstract
BACKGROUND & AIMS Covalently closed circular DNA (cccDNA) is the episomal form of the HBV genome that stably resides in the nucleus of infected hepatocytes. cccDNA is the template for the transcription of 6 major viral RNAs, i.e. preC, pg, preS1/2, S and HBx RNA. All viral transcripts share the same 3' end and are all to various degrees subsets of each other. Especially under infection conditions, it has been difficult to study in depth the transcription of the different viral transcripts. We thus wanted to develop a method with which we could easily detect the full spectrum of viral RNAs in any lab. METHODS We set up an HBV full-length 5'RACE (rapid amplification of cDNA ends) method with which we measured and characterized the full spectrum of viral RNAs in cell culture and in chronically infected patients. RESULTS In addition to canonical HBx transcripts coding for full-length X, we identified shorter HBx transcripts potentially coding for short X proteins. We showed that interferon-β treatment leads to a strong reduction of preC and pgRNAs but has only a moderate effect on the other viral transcripts. We found pgRNA, 1 spliced pgRNA variant and a variety of HBx transcripts associated with viral particles generated by HepAD38 cells. The different HBx RNAs are both capped and uncapped. Lastly, we identified 3 major categories of circulating RNA species in patients with chronic HBV infection: pgRNA, spliced pgRNA variants and HBx. CONCLUSIONS This HBV full-length 5'RACE method should significantly contribute to the understanding of HBV transcription during the course of infection and therapy and may guide the development of novel therapies aimed at targeting cccDNA. LAY SUMMARY Especially under infection conditions, it has been difficult to study the different hepatitis B virus transcripts in depth. This study introduces a new method that can be used in any standard lab to discriminate all hepatitis B viral transcripts in cell culture and in the serum of patients.
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Affiliation(s)
- Bernd Stadelmayer
- INSERM U1052, CNRS UMR-5286, Cancer Research Center of Lyon (CRCL), Lyon, 69008, France; University of Lyon, Université Claude-Bernard (UCBL), 69008 Lyon, France.
| | - Audrey Diederichs
- INSERM U1052, CNRS UMR-5286, Cancer Research Center of Lyon (CRCL), Lyon, 69008, France; University of Lyon, Université Claude-Bernard (UCBL), 69008 Lyon, France
| | - Fleur Chapus
- INSERM U1052, CNRS UMR-5286, Cancer Research Center of Lyon (CRCL), Lyon, 69008, France; University of Lyon, Université Claude-Bernard (UCBL), 69008 Lyon, France
| | - Michel Rivoire
- INSERM U1032, Centre Léon Bérard (CLB), 69008 Lyon, France
| | - Gregory Neveu
- Evotec, 1541 Avenue Marcel Mérieux, 69280 Marcy l'Etoile, France
| | - Antoine Alam
- Evotec, 1541 Avenue Marcel Mérieux, 69280 Marcy l'Etoile, France
| | - Laurent Fraisse
- Evotec, 1541 Avenue Marcel Mérieux, 69280 Marcy l'Etoile, France
| | - Kara Carter
- Evotec, 1541 Avenue Marcel Mérieux, 69280 Marcy l'Etoile, France
| | - Barbara Testoni
- INSERM U1052, CNRS UMR-5286, Cancer Research Center of Lyon (CRCL), Lyon, 69008, France; University of Lyon, Université Claude-Bernard (UCBL), 69008 Lyon, France
| | - Fabien Zoulim
- INSERM U1052, CNRS UMR-5286, Cancer Research Center of Lyon (CRCL), Lyon, 69008, France; University of Lyon, Université Claude-Bernard (UCBL), 69008 Lyon, France; Hospices Civils de Lyon (HCL), 69002 Lyon, France.
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28
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Minor MM, Hollinger FB, McNees AL, Jung SY, Jain A, Hyser JM, Bissig KD, Slagle BL. Hepatitis B Virus HBx Protein Mediates the Degradation of Host Restriction Factors through the Cullin 4 DDB1 E3 Ubiquitin Ligase Complex. Cells 2020; 9:E834. [PMID: 32235678 PMCID: PMC7226812 DOI: 10.3390/cells9040834] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2020] [Revised: 03/24/2020] [Accepted: 03/25/2020] [Indexed: 02/06/2023] Open
Abstract
The hepatitis B virus (HBV) regulatory HBx protein is required for infection, and its binding to cellular damaged DNA binding protein 1 (DDB1) is critical for this function. DDB1 is an adaptor protein for the cullin 4A Really Interesting New Gene (RING) E3 ubiquitin ligase (CRL4) complex and functions by binding cellular DDB1 cullin associated factor (DCAF) receptor proteins that recruit substrates for ubiquitination and degradation. We compared the proteins found in the CRL4 complex immunoprecipitated from uninfected versus HBV-infected hepatocytes from human liver chimeric mice for insight into mechanisms by which HBV and the cell interact within the CRL4 complex. Consistent with its role as a viral DCAF, HBx was found in the HBV CRL4 complexes. In tissue culture transfection experiments, we showed that HBx expression led to decreased levels of known restriction factor structural maintenance of chromosomes protein 6 (SMC6) and putative restriction factors stromal interaction molecule 1 (STIM1, zinc finger E-box binding homeobox 2 (ZEB2), and proteasome activator subunit 4 (PSME4). Moreover, silencing of these proteins led to increased HBV replication in the HepG2-sodium taurocholate cotransporting polypeptide (NTCP) infection model. We also identified cellular DCAF receptors in CRL4 complexes from humanized mice. Increasing amounts of HBx did not reveal competitive DCAF binding to cullin4 (CUL4)-DDB1 in plasmid-transfected cells. Our results suggest a model in which HBx benefits virus replication by directly or indirectly degrading multiple cellular restriction factors.
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Affiliation(s)
- Marissa M. Minor
- Department of Molecular Virology and Microbiology, Baylor College of Medicine, Houston, TX 77030, USA; (M.M.M.); (F.B.H.); (A.L.M.); (J.M.H.)
| | - F. Blaine Hollinger
- Department of Molecular Virology and Microbiology, Baylor College of Medicine, Houston, TX 77030, USA; (M.M.M.); (F.B.H.); (A.L.M.); (J.M.H.)
| | - Adrienne L. McNees
- Department of Molecular Virology and Microbiology, Baylor College of Medicine, Houston, TX 77030, USA; (M.M.M.); (F.B.H.); (A.L.M.); (J.M.H.)
- Dan L. Duncan Cancer Center, Baylor College of Medicine, Houston, TX 77030, USA;
| | - Sung Yun Jung
- Dan L. Duncan Cancer Center, Baylor College of Medicine, Houston, TX 77030, USA;
- Department of Biochemistry, Baylor College of Medicine, Houston, TX 77030, USA
| | - Antrix Jain
- Mass Spectrometry Proteomics Core, Baylor College of Medicine, Houston, TX 77030, USA;
| | - Joseph M. Hyser
- Department of Molecular Virology and Microbiology, Baylor College of Medicine, Houston, TX 77030, USA; (M.M.M.); (F.B.H.); (A.L.M.); (J.M.H.)
| | - Karl-Dimiter Bissig
- Center for Cell and Gene Therapy, Baylor College of Medicine, Houston, TX 77030, USA;
| | - Betty L. Slagle
- Department of Molecular Virology and Microbiology, Baylor College of Medicine, Houston, TX 77030, USA; (M.M.M.); (F.B.H.); (A.L.M.); (J.M.H.)
- Dan L. Duncan Cancer Center, Baylor College of Medicine, Houston, TX 77030, USA;
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29
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HBV X protein mutations affect HBV transcription and association of histone-modifying enzymes with covalently closed circular DNA. Sci Rep 2020; 10:802. [PMID: 31964944 PMCID: PMC6972884 DOI: 10.1038/s41598-020-57637-z] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2019] [Accepted: 12/24/2019] [Indexed: 12/13/2022] Open
Abstract
The hepatitis B X protein (HBx) plays a role in the epigenetic regulation of hepatitis B virus (HBV) replication. This study investigated the effects of HBx mutations on HBV transcription and the recruitment of HBx, histone acetyl-transferase P300 and histone deacetylase 1 (HDAC1) to circularized HBV DNA (which resembles covalently closed circular DNA [cccDNA]). Compared with wild type, majority of mutants had lower levels of intracellular HBV RNA (44–77% reduction) and secretory HBsAg (25–81% reduction), and 12 mutants had a reduction in intracellular encapsidated HBV DNA (33–64% reduction). Eight mutants with >70% reduction in HBV RNA and/or HBsAg were selected for chromatin immunoprecipitation analysis. Four HBx mutants with mutations in amino acid residues 55–60 and 121–126 had a lower degree of HBx-cccDNA association than wild type HBx (mean % input: 0.02–0.64% vs. 3.08% in wild type). A reduced association between cccDNA and P300 (mean % input: 0.69–1.81% vs. 3.48% in wild type) and an augmented association with HDAC1 (mean % input: 4.01–14.0% vs. 1.53% in wild type) were detected. HBx amino acid residues 55–60 and 121–126 may play an important role in HBV transcription regulation, via their impeded interaction with cccDNA and altered recruitment of histone modifying enzymes to cccDNA.
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30
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Wang F, Shen F, Wang Y, Li Z, Chen J, Yuan Z. Residues Asn118 and Glu119 of hepatitis B virus X protein are critical for HBx-mediated inhibition of RIG-I-MAVS signaling. Virology 2020; 539:92-103. [PMID: 31706164 DOI: 10.1016/j.virol.2019.10.009] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2019] [Revised: 06/24/2019] [Accepted: 10/21/2019] [Indexed: 12/13/2022]
Abstract
Hepatitis B virus (HBV) X protein (HBx) has been reported to counteract the innate immune responses through interfering with the pattern recognition receptors signaling activated by retinoic acid-inducible gene-I (RIG-I)-mitochondrial antiviral signaling protein (MAVS). Here, we showed that, compared to the HBx derived from genotype (gt) A, C and D, HBx of gtB exhibited more potent inhibitory activity on the RIG-I-MAVS-mediated interferon-β promoter activation. Functional analysis of the genotype-associated differences in amino acid sequence and the reciprocal mutation experiments in transient-transfection and infection cell models revealed that HBx with asparagine (N) and glutamic acid (E) at 118-119 positions inhibited RIG-I signaling and interacted with MAVS more efficiently than that with lysine (K) and aspartic acid (D). An impaired RIG-I-induced MAVS aggregation was observed in the presence of HBx-118N119E while MAVS-TRAF3 interaction was not affected. These results implicated that HBx gene heterogeneity may affect the innate immune responses to HBV infection.
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Affiliation(s)
- Fan Wang
- MOE/NHC/CAMS Key Laboratory of Medical Molecular Virology, School of Basic Medical Sciences, Shanghai Medical College, Fudan University, Shanghai, 200032, China
| | - Fang Shen
- MOE/NHC/CAMS Key Laboratory of Medical Molecular Virology, School of Basic Medical Sciences, Shanghai Medical College, Fudan University, Shanghai, 200032, China
| | - Yang Wang
- MOE/NHC/CAMS Key Laboratory of Medical Molecular Virology, School of Basic Medical Sciences, Shanghai Medical College, Fudan University, Shanghai, 200032, China
| | - Ze Li
- Institute of Biomedical Sciences, Shanghai Medical College, Fudan University, Shanghai, 200032, China
| | - Jieliang Chen
- MOE/NHC/CAMS Key Laboratory of Medical Molecular Virology, School of Basic Medical Sciences, Shanghai Medical College, Fudan University, Shanghai, 200032, China.
| | - Zhenghong Yuan
- MOE/NHC/CAMS Key Laboratory of Medical Molecular Virology, School of Basic Medical Sciences, Shanghai Medical College, Fudan University, Shanghai, 200032, China.
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Rivière L, Quioc-Salomon B, Fallot G, Halgand B, Féray C, Buendia MA, Neuveut C. Hepatitis B virus replicating in hepatocellular carcinoma encodes HBx variants with preserved ability to antagonize restriction by Smc5/6. Antiviral Res 2019; 172:104618. [DOI: 10.1016/j.antiviral.2019.104618] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2019] [Revised: 08/08/2019] [Accepted: 10/05/2019] [Indexed: 12/26/2022]
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Spatiotemporal Analysis of Hepatitis B Virus X Protein in Primary Human Hepatocytes. J Virol 2019; 93:JVI.00248-19. [PMID: 31167911 PMCID: PMC6675897 DOI: 10.1128/jvi.00248-19] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2019] [Accepted: 05/28/2019] [Indexed: 12/18/2022] Open
Abstract
Hepatitis B virus X protein (HBx) is a promising drug target since it promotes the degradation of the host structural maintenance of chromosomes 5/6 complex (Smc5/6) that inhibits HBV transcription. To date, it has not been possible to study HBx in physiologically relevant cell culture systems due to the lack of a highly specific and selective HBx antibody. In this study, we developed a novel monoclonal HBx antibody and performed a spatiotemporal analysis of HBx in a natural infection system. This revealed that HBx localizes to the nucleus of infected cells, is expressed shortly after infection, and has a short half-life. In addition, we demonstrated that inhibiting HBx expression or function promotes the reappearance of Smc6 in the nucleus of infected cells. These data provide new insights into HBx and underscore its potential as a novel target for the treatment of chronic HBV infection. The structural maintenance of chromosomes 5/6 complex (Smc5/6) is a host restriction factor that suppresses hepatitis B virus (HBV) transcription. HBV counters this restriction by expressing the X protein (HBx), which redirects the host DNA damage-binding protein 1 (DDB1) E3 ubiquitin ligase to target Smc5/6 for degradation. HBx is an attractive therapeutic target for the treatment of chronic hepatitis B (CHB), but it is challenging to study this important viral protein in the context of natural infection due to the lack of a highly specific and sensitive HBx antibody. In this study, we developed a novel monoclonal antibody that enables detection of HBx protein in HBV-infected primary human hepatocytes (PHH) by Western blotting and immunofluorescence. Confocal imaging studies with this antibody demonstrated that HBx is predominantly located in the nucleus of HBV-infected PHH, where it exhibits a diffuse staining pattern. In contrast, a DDB1-binding-deficient HBx mutant was detected in both the cytoplasm and nucleus, suggesting that the DDB1 interaction plays an important role in the nuclear localization of HBx. Our study also revealed that HBx is expressed early after infection and has a short half-life (∼3 h) in HBV-infected PHH. In addition, we found that treatment with small interfering RNAs (siRNAs) that target DDB1 or HBx mRNA decreased HBx protein levels and led to the reappearance of Smc6 in the nuclei of HBV-infected PHH. Collectively, these studies provide the first spatiotemporal analysis of HBx in a natural infection system and also suggest that HBV transcriptional silencing by Smc5/6 can be restored by therapeutic targeting of HBx. IMPORTANCE Hepatitis B virus X protein (HBx) is a promising drug target since it promotes the degradation of the host structural maintenance of chromosomes 5/6 complex (Smc5/6) that inhibits HBV transcription. To date, it has not been possible to study HBx in physiologically relevant cell culture systems due to the lack of a highly specific and selective HBx antibody. In this study, we developed a novel monoclonal HBx antibody and performed a spatiotemporal analysis of HBx in a natural infection system. This revealed that HBx localizes to the nucleus of infected cells, is expressed shortly after infection, and has a short half-life. In addition, we demonstrated that inhibiting HBx expression or function promotes the reappearance of Smc6 in the nucleus of infected cells. These data provide new insights into HBx and underscore its potential as a novel target for the treatment of chronic HBV infection.
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Hepatitis B Virus X Protein Function Requires Zinc Binding. J Virol 2019; 93:JVI.00250-19. [PMID: 31167910 PMCID: PMC6675892 DOI: 10.1128/jvi.00250-19] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2019] [Accepted: 05/28/2019] [Indexed: 12/18/2022] Open
Abstract
The host structural maintenance of chromosomes 5/6 complex (Smc5/6) suppresses hepatitis B virus (HBV) transcription. HBV counters this restriction by expressing the X protein (HBx), which redirects the cellular DNA damage-binding protein 1 (DDB1)-containing E3 ubiquitin ligase to target Smc5/6 for degradation. However, the details of how HBx modulates the interaction between DDB1 and Smc5/6 remain to be determined. In this study, we performed biophysical analyses of recombinant HBx and functional analysis of HBx mutants in HBV-infected primary human hepatocytes (PHH) to identify key regions and residues that are required for HBx function. We determined that recombinant HBx is soluble and exhibits stoichiometric zinc binding when expressed in the presence of DDB1. Mass spectrometry-based hydrogen-deuterium exchange and cysteine-specific chemical footprinting of the HBx:DDB1 complex identified several HBx cysteine residues (located between amino acids 61 and 137) that are likely involved in zinc binding. These cysteine residues did not form disulfide bonds in HBx expressed in human cells. In line with the biophysical data, functional analysis demonstrated that HBx amino acids 45 to 140 are required for Smc6 degradation and HBV transcription in PHH. Furthermore, site-directed mutagenesis determined that C61, C69, C137, and H139 are necessary for HBx function, although they are likely not essential for DDB1 binding. This CCCH motif is highly conserved in HBV as well as in the X proteins from various mammalian hepadnaviruses. Collectively, our data indicate that the essential HBx cysteine and histidine residues form a zinc-binding motif that is required for HBx function.IMPORTANCE The structural maintenance of chromosomes 5/6 complex (Smc5/6) is a host restriction factor that suppresses HBV transcription. HBV counters this restriction by expressing HBV X protein (HBx), which redirects a host ubiquitin ligase to target Smc5/6 for degradation. Despite this recent advance in understanding HBx function, the key regions and residues of HBx required for Smc5/6 degradation have not been determined. In the present study, we performed biochemical, biophysical, and cell-based analyses of HBx. By doing so, we mapped the minimal functional region of HBx and identified a highly conserved CCCH motif in HBx that is likely responsible for coordinating zinc and is essential for HBx function. We also developed a method to produce soluble recombinant HBx protein that likely adopts a physiologically relevant conformation. Collectively, this study provides new insights into the HBx structure-function relationship and suggests a new approach for structural studies of this enigmatic viral regulatory protein.
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Zhang TY, Chen HY, Cao JL, Xiong HL, Mo XB, Li TL, Kang XZ, Zhao JH, Yin B, Zhao X, Huang CH, Yuan Q, Xue D, Xia NS, Yuan YA. Structural and functional analyses of hepatitis B virus X protein BH3-like domain and Bcl-xL interaction. Nat Commun 2019; 10:3192. [PMID: 31324803 PMCID: PMC6642116 DOI: 10.1038/s41467-019-11173-1] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2017] [Accepted: 06/25/2019] [Indexed: 12/12/2022] Open
Abstract
Hepatitis B virus (HBV) X protein, HBx, interacts with anti-apoptotic Bcl-2 and Bcl-xL proteins through its BH3-like motif to promote HBV replication and cytotoxicity. Here we report the crystal structure of HBx BH3-like motif in complex with Bcl-xL where the BH3-like motif adopts a short α-helix to snuggle into a hydrophobic pocket in Bcl-xL via its noncanonical Trp120 residue and conserved Leu123 residue. This binding pocket is ~2 Å away from the canonical BH3-only binding pocket in structures of Bcl-xL with proapoptotic BH3-only proteins. Mutations altering Trp120 and Leu123 in HBx impair its binding to Bcl-xL in vitro and HBV replication in vivo, confirming the importance of this motif to HBV. A HBx BH3-like peptide, HBx-aa113-135, restores HBV replication from a HBx-null HBV replicon, while a shorter peptide, HBx-aa118-127, inhibits HBV replication. These results provide crucial structural and functional insights into drug designs for inhibiting HBV replication and treating HBV patients.
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Affiliation(s)
- Tian-Ying Zhang
- State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, School of Public Health and School of Life Sciences, Xiamen University, 361102, Xiamen, China.,National Institute of Diagnostics and Vaccine Development in Infectious Diseases, School of Public Health and School of Life Sciences, Xiamen University, 361102, Xiamen, China
| | - Hong-Ying Chen
- National University of Singapore (Suzhou) Research Institute, 377 Lin Quan Street, Suzhou Industrial Park, 215123, Jiangsu, China
| | - Jia-Li Cao
- State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, School of Public Health and School of Life Sciences, Xiamen University, 361102, Xiamen, China.,National Institute of Diagnostics and Vaccine Development in Infectious Diseases, School of Public Health and School of Life Sciences, Xiamen University, 361102, Xiamen, China
| | - Hua-Long Xiong
- State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, School of Public Health and School of Life Sciences, Xiamen University, 361102, Xiamen, China.,National Institute of Diagnostics and Vaccine Development in Infectious Diseases, School of Public Health and School of Life Sciences, Xiamen University, 361102, Xiamen, China
| | - Xiao-Bing Mo
- National University of Singapore (Suzhou) Research Institute, 377 Lin Quan Street, Suzhou Industrial Park, 215123, Jiangsu, China
| | - Tian-Liang Li
- Department of Molecular, Cellular and Developmental Biology, University of Colorado, Boulder, CO, 80309, USA
| | - Xiao-Zhen Kang
- State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, School of Public Health and School of Life Sciences, Xiamen University, 361102, Xiamen, China.,National Institute of Diagnostics and Vaccine Development in Infectious Diseases, School of Public Health and School of Life Sciences, Xiamen University, 361102, Xiamen, China
| | - Jing-Hua Zhao
- State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, School of Public Health and School of Life Sciences, Xiamen University, 361102, Xiamen, China.,National Institute of Diagnostics and Vaccine Development in Infectious Diseases, School of Public Health and School of Life Sciences, Xiamen University, 361102, Xiamen, China
| | - Bo Yin
- National University of Singapore (Suzhou) Research Institute, 377 Lin Quan Street, Suzhou Industrial Park, 215123, Jiangsu, China
| | - Xiang Zhao
- School of Life Sciences and Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Tsinghua University, 100084, Beijing, China
| | - Cheng-Hao Huang
- State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, School of Public Health and School of Life Sciences, Xiamen University, 361102, Xiamen, China.,National Institute of Diagnostics and Vaccine Development in Infectious Diseases, School of Public Health and School of Life Sciences, Xiamen University, 361102, Xiamen, China
| | - Quan Yuan
- State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, School of Public Health and School of Life Sciences, Xiamen University, 361102, Xiamen, China. .,National Institute of Diagnostics and Vaccine Development in Infectious Diseases, School of Public Health and School of Life Sciences, Xiamen University, 361102, Xiamen, China.
| | - Ding Xue
- Department of Molecular, Cellular and Developmental Biology, University of Colorado, Boulder, CO, 80309, USA. .,School of Life Sciences and Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Tsinghua University, 100084, Beijing, China.
| | - Ning-Shao Xia
- State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, School of Public Health and School of Life Sciences, Xiamen University, 361102, Xiamen, China. .,National Institute of Diagnostics and Vaccine Development in Infectious Diseases, School of Public Health and School of Life Sciences, Xiamen University, 361102, Xiamen, China.
| | - Y Adam Yuan
- National University of Singapore (Suzhou) Research Institute, 377 Lin Quan Street, Suzhou Industrial Park, 215123, Jiangsu, China.,Department of Biological Sciences and Centre for Bioimaging Sciences, National University of Singapore, 14 Science Drive 4, Singapore, 117543, Singapore
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Peroxiredoxin 1, a Novel HBx-Interacting Protein, Interacts with Exosome Component 5 and Negatively Regulates Hepatitis B Virus (HBV) Propagation through Degradation of HBV RNA. J Virol 2019; 93:JVI.02203-18. [PMID: 30567989 DOI: 10.1128/jvi.02203-18] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2018] [Accepted: 12/12/2018] [Indexed: 12/20/2022] Open
Abstract
Hepatitis B virus (HBV) infection is a major risk factor for the development of chronic liver diseases, including cirrhosis and hepatocellular carcinoma (HCC). A growing body of evidence suggests that HBV X protein (HBx) plays a crucial role in viral replication and HCC development. Here, we identified peroxiredoxin 1 (Prdx1), a cellular hydrogen peroxide scavenger, as a novel HBx-interacting protein. Coimmunoprecipitation analysis coupled with site-directed mutagenesis revealed that the region from amino acids 17 to 20 of the HBx, particularly HBx Cys17, is responsible for the interaction with Prdx1. Knockdown of Prdx1 by siRNA significantly increased the levels of intracellular HBV RNA, HBV antigens, and extracellular HBV DNA, whereas knockdown of Prdx1 did not increase the activities of HBV core, enhancer I (Enh1)/X, preS1, and preS2/S promoters. Kinetic analysis of HBV RNA showed that knockdown of Prdx1 inhibited HBV RNA decay, suggesting that Prdx1 reduces HBV RNA levels posttranscriptionally. The RNA coimmunoprecipitation assay revealed that Prdx1 interacted with HBV RNA. The exosome component 5 (Exosc5), a member of the RNA exosome complexes, was coimmunoprecipitated with Prdx1, suggesting its role in regulation of HBV RNA stability. Taken together, these results suggest that Prdx1 and Exosc5 play crucial roles in host defense mechanisms against HBV infection.IMPORTANCE Hepatitis B virus (HBV) infection is a major global health problem. HBx plays important roles in HBV replication and viral carcinogenesis through its interaction with host factors. In this study, we identified Prdx1 as a novel HBx-binding protein. We provide evidence suggesting that Prdx1 promotes HBV RNA decay through interaction with HBV RNA and Exosc5, leading to downregulation of HBV RNA. These results suggest that Prdx1 negatively regulates HBV propagation. Our findings may shed new light on the roles of Prdx1 and Exosc5 in host defense mechanisms in HBV infection.
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Hou L, Zhao J, Gao S, Ji T, Song T, Li Y, Wang J, Geng C, Long M, Chen J, Lin H, Cai X, Cang Y. Restriction of hepatitis B virus replication by c-Abl-induced proteasomal degradation of the viral polymerase. SCIENCE ADVANCES 2019; 5:eaau7130. [PMID: 30775435 PMCID: PMC6365112 DOI: 10.1126/sciadv.aau7130] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/16/2018] [Accepted: 12/19/2018] [Indexed: 05/13/2023]
Abstract
About 257 million people with chronic infection of hepatitis B virus (HBV) worldwide are at high risk of developing terminal liver diseases. Reactivation of virus replication has been frequently reported in those patient populations receiving imatinib (an Abl kinase inhibitor) or bortezomib (a proteasome inhibitor) to treat concurrent diseases, but the underlying mechanism for this reactivation is unknown. We report that the HBV polymerase protein is recruited by Cdt2 to the cullin-RING ligase 4 (CRL4) for ubiquitination and proteasome degradation and that this process is stimulated by the c-Abl nonreceptor tyrosine kinase. Genetic ablation of the Abl-CRL4Cdt2 axis or pharmaceutical inhibition of this process stabilizes HBV polymerase protein and increases viral loads in HBV-infected liver cancer cell lines. Our study reveals a kinase-dependent activation of CRL4 ubiquitin ligase that can be targeted for blocking HBV replication.
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Affiliation(s)
- Lidan Hou
- Life Sciences Institute, Zhejiang University, Hangzhou, Zhejiang 310058, China
- School of Life Science and Technology, ShanghaiTech University, Shanghai 201210, China
| | - Jie Zhao
- Department of General Surgery, Sir Run Run Shaw Hospital, College of Medicine, Zhejiang University, Hangzhou, Zhejiang 310058, China
| | - Shaobing Gao
- Life Sciences Institute, Zhejiang University, Hangzhou, Zhejiang 310058, China
- Affiliated Cancer Hospital of Zhengzhou University, Zhengzhou, Henan 450008, China
| | - Tong Ji
- Department of General Surgery, Sir Run Run Shaw Hospital, College of Medicine, Zhejiang University, Hangzhou, Zhejiang 310058, China
| | - Tianyu Song
- Life Sciences Institute, Zhejiang University, Hangzhou, Zhejiang 310058, China
- School of Life Science and Technology, ShanghaiTech University, Shanghai 201210, China
| | - Yining Li
- Life Sciences Institute, Zhejiang University, Hangzhou, Zhejiang 310058, China
| | - Jingjie Wang
- Life Sciences Institute, Zhejiang University, Hangzhou, Zhejiang 310058, China
| | - Chenlu Geng
- Life Sciences Institute, Zhejiang University, Hangzhou, Zhejiang 310058, China
| | - Min Long
- Life Sciences Institute, Zhejiang University, Hangzhou, Zhejiang 310058, China
| | - Jiang Chen
- Department of General Surgery, Sir Run Run Shaw Hospital, College of Medicine, Zhejiang University, Hangzhou, Zhejiang 310058, China
| | - Hui Lin
- Department of General Surgery, Sir Run Run Shaw Hospital, College of Medicine, Zhejiang University, Hangzhou, Zhejiang 310058, China
| | - Xiujun Cai
- Department of General Surgery, Sir Run Run Shaw Hospital, College of Medicine, Zhejiang University, Hangzhou, Zhejiang 310058, China
| | - Yong Cang
- School of Life Science and Technology, ShanghaiTech University, Shanghai 201210, China
- Corresponding author.
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Lee H, Jeong H, Lee SY, Kim SS, Jang KL. Hepatitis B Virus X Protein Stimulates Virus Replication Via DNA Methylation of the C-1619 in Covalently Closed Circular DNA. Mol Cells 2019; 42:67-78. [PMID: 30518174 PMCID: PMC6354056 DOI: 10.14348/molcells.2018.0255] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2018] [Revised: 11/22/2018] [Accepted: 11/26/2018] [Indexed: 02/06/2023] Open
Abstract
Methylation of HBV cccDNA has been detected in vivo and in vitro; however, the mechanism and its effects on HBV replication remain unclear. HBx derived from a 1.2-mer HBV replicon upregulated protein levels and enzyme activities of DNA methyltransferase 1 (DNMT1), 3a, and 3b, resulting in methylation of the negative regulatory region (NRE) in cccDNA, while none of these effects were observed with an HBx-null mutant. The HBx-positive HBV cccDNA expressed higher levels of HBc and produced about 4-fold higher levels of HBV particles than those from the HBx-null counterpart. For these effects, HBx interrupted the action of NRE binding protein via methylation of the C-1619 within NRE, resulting in activation of the core promoter. Treatment with 5-Aza-2'dC or DNMT1 knock-down drastically impaired the ability of HBx to activate the core promoter and stimulate HBV replication in 1.2-mer HBV replicon and in vitro infection systems, indicating the positive role of HBx-mediated cccDNA methylation in HBV replication.
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Affiliation(s)
- Hyehyeon Lee
- Department of Microbiology, College of Natural Science, Pusan National University, Busan 46241,
Korea
| | - Hyerin Jeong
- Department of Microbiology, College of Natural Science, Pusan National University, Busan 46241,
Korea
| | - Sun Young Lee
- Department of Microbiology, College of Natural Science, Pusan National University, Busan 46241,
Korea
| | - Soo Shin Kim
- Department of Microbiology, College of Natural Science, Pusan National University, Busan 46241,
Korea
| | - Kyung Lib Jang
- Department of Microbiology, College of Natural Science, Pusan National University, Busan 46241,
Korea
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38
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39
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Smc5/6 Antagonism by HBx Is an Evolutionarily Conserved Function of Hepatitis B Virus Infection in Mammals. J Virol 2018; 92:JVI.00769-18. [PMID: 29848586 DOI: 10.1128/jvi.00769-18] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2018] [Accepted: 05/09/2018] [Indexed: 12/14/2022] Open
Abstract
Chronic infection with hepatitis B virus (HBV) is a major cause of liver disease and cancer in humans. HBVs (family Hepadnaviridae) have been associated with mammals for millions of years. Recently, the Smc5/6 complex, known for its essential housekeeping functions in genome maintenance, was identified as an antiviral restriction factor of human HBV. The virus has, however, evolved to counteract this defense mechanism by degrading the complex via its regulatory HBx protein. Whether the antiviral activity of the Smc5/6 complex against hepadnaviruses is an important and evolutionarily conserved function is unknown. In this study, we used an evolutionary and functional approach to address this question. We first performed phylogenetic and positive selection analyses of the Smc5/6 complex subunits and found that they have been conserved in primates and mammals. Yet, Smc6 showed marks of adaptive evolution, potentially reminiscent of a virus-host "arms race." We then functionally tested the HBx proteins from six divergent hepadnaviruses naturally infecting primates, rodents, and bats. We demonstrate that despite little sequence homology, these HBx proteins efficiently degraded mammalian Smc5/6 complexes, independently of the host species and of the sites under positive selection. Importantly, all HBx proteins also rescued the replication of an HBx-deficient HBV in primary human hepatocytes. These findings point to an evolutionarily conserved requirement for Smc5/6 inactivation by HBx, showing that Smc5/6 antiviral activity has been an important defense mechanism against hepadnaviruses in mammals. It will be interesting to investigate whether Smc5/6 may further be a restriction factor of other, yet-unidentified viruses that may have driven some of its adaptation.IMPORTANCE Infection with hepatitis B virus (HBV) led to 887,000 human deaths in 2015. HBV has been coevolving with mammals for millions of years. Recently, the Smc5/6 complex, which has essential housekeeping functions, was identified as a restriction factor of human HBV antagonized by the regulatory HBx protein. Here we address whether the antiviral activity of Smc5/6 is an important evolutionarily conserved function. We found that all six subunits of Smc5/6 have been conserved in primates, with only Smc6 showing signatures of an "evolutionary arms race." Using evolution-guided functional analyses that included infections of primary human hepatocytes, we demonstrated that HBx proteins from very divergent mammalian HBVs could all efficiently antagonize Smc5/6, independently of the host species and sites under positive selection. These findings show that Smc5/6 antiviral activity against HBV is an important function in mammals. They also raise the intriguing possibility that Smc5/6 may restrict other, yet-unidentified viruses.
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Wu Q, Li Z, Liu Q. An important role of SREBP-1 in HBV and HCV co-replication inhibition by PTEN. Virology 2018; 520:94-102. [PMID: 29803738 DOI: 10.1016/j.virol.2018.05.011] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2018] [Revised: 05/15/2018] [Accepted: 05/16/2018] [Indexed: 02/07/2023]
Abstract
HBV HCV co-infection leads to more severe liver diseases including liver cancer than mono-infections. Phosphatase and tensin homolog deleted on chromosome 10 (PTEN), a tumor suppressor, inhibits sterol regulatory element binding protein-1 (SREBP-1). In this study, we characterized the effect of the PTEN - SREBP-1 pathway on HBV HCV co-replication in a cellular model. We found that HBV and HCV can co-replicate in Huh-7 cells with no interference. Overexpression of PTEN inhibits, whereas PTEN knockdown enhances, HBV replication as well as HBV and HCV co-replication. Knocking down SREBP-1 decreases HBV replication in an HBx-dependent manner. SREBP-1 knockdown also decreases HCV replication. PTEN knockdown is concomitant with increased nuclear SREBP-1 levels. PTEN and SREBP-1 double knockdown results in intermediate levels of HBV and HCV replication in mono- and co-replication scenarios. Taken together, we demonstrated, for the first time, that the PTEN - SREBP-1 pathway can regulate HBV HCV co-replication.
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Affiliation(s)
- Qi Wu
- Vaccine and Infectious Disease Organization-International Vaccine Centre (VIDO-InterVac), University of Saskatchewan 120 Veterinary Road, Saskatoon, Saskatchewan, Canada S7N 5E3; Department of Veterinary Microbiology, University of Saskatchewan, Canada
| | - Zhubing Li
- Vaccine and Infectious Disease Organization-International Vaccine Centre (VIDO-InterVac), University of Saskatchewan 120 Veterinary Road, Saskatoon, Saskatchewan, Canada S7N 5E3; School of Public Health Vaccinology and Immunotherapeutics, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
| | - Qiang Liu
- Vaccine and Infectious Disease Organization-International Vaccine Centre (VIDO-InterVac), University of Saskatchewan 120 Veterinary Road, Saskatoon, Saskatchewan, Canada S7N 5E3; Department of Veterinary Microbiology, University of Saskatchewan, Canada; School of Public Health Vaccinology and Immunotherapeutics, University of Saskatchewan, Saskatoon, Saskatchewan, Canada.
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Role of HBx in hepatitis B virus persistence and its therapeutic implications. Curr Opin Virol 2018; 30:32-38. [PMID: 29454995 DOI: 10.1016/j.coviro.2018.01.007] [Citation(s) in RCA: 67] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2017] [Revised: 01/17/2018] [Accepted: 01/24/2018] [Indexed: 12/12/2022]
Abstract
Chronic hepatitis B virus infection is a significant risk factor for cirrhosis and hepatocellular carcinoma. The HBx protein is required for virus replication, but the lack of robust infection models has hindered our understanding of HBx functions that could be targeted for antiviral purposes. We briefly review three properties of HBx: its binding to DDB1 and its regulation of cell survival and metabolism, to illustrate how a single viral protein can have multiple effects in a cell. We propose that different functions of HBx are needed, depending on the changing hepatocyte environment encountered during a chronic virus infection, and that these functions might serve as novel therapeutic targets for inhibiting hepatitis B virus replication and the development of associated diseases.
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42
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Murphy CM, Xu Y, Li F, Nio K, Reszka-Blanco N, Li X, Wu Y, Yu Y, Xiong Y, Su L. Hepatitis B Virus X Protein Promotes Degradation of SMC5/6 to Enhance HBV Replication. Cell Rep 2017; 16:2846-2854. [PMID: 27626656 DOI: 10.1016/j.celrep.2016.08.026] [Citation(s) in RCA: 202] [Impact Index Per Article: 28.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2016] [Revised: 07/06/2016] [Accepted: 08/05/2016] [Indexed: 12/15/2022] Open
Abstract
The hepatitis B virus (HBV) regulatory protein X (HBx) activates gene expression from the HBV covalently closed circular DNA (cccDNA) genome. Interaction of HBx with the DDB1-CUL4-ROC1 (CRL4) E3 ligase is critical for this function. Using substrate-trapping proteomics, we identified the structural maintenance of chromosomes (SMC) complex proteins SMC5 and SMC6 as CRL4(HBx) substrates. HBx expression and HBV infection degraded the SMC5/6 complex in human hepatocytes in vitro and in humanized mice in vivo. HBx targets SMC5/6 for ubiquitylation by the CRL4(HBx) E3 ligase and subsequent degradation by the proteasome. Using a minicircle HBV (mcHBV) reporter system with HBx-dependent activity, we demonstrate that SMC5/6 knockdown, or inhibition with a dominant-negative SMC6, enhance HBx null mcHBV-Gluc gene expression. Furthermore, SMC5/6 knockdown rescued HBx-deficient HBV replication in human hepatocytes. These results indicate that a primary function of HBx is to degrade SMC5/6, which restricts HBV replication by inhibiting HBV gene expression.
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Affiliation(s)
- Christopher M Murphy
- Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA; Department of Microbiology and Immunology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Yanping Xu
- Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA; Department of Biochemistry and Biophysics, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Feng Li
- Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA; Department of Microbiology and Immunology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Kouki Nio
- Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA; Department of Microbiology and Immunology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Natalia Reszka-Blanco
- Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA; Department of Microbiology and Immunology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Xiaodong Li
- Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA; Department of Microbiology and Immunology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Yaxu Wu
- Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA; Department of Microbiology and Immunology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Yanbao Yu
- J. Craig Venter Institute, 9714 Medical Center Drive, Rockville, MD 20850, USA
| | - Yue Xiong
- Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA; Department of Biochemistry and Biophysics, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA.
| | - Lishan Su
- Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA; Department of Microbiology and Immunology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA.
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Gómez-Moreno A, Garaigorta U. Hepatitis B Virus and DNA Damage Response: Interactions and Consequences for the Infection. Viruses 2017; 9:v9100304. [PMID: 29048354 PMCID: PMC5691655 DOI: 10.3390/v9100304] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2017] [Revised: 10/13/2017] [Accepted: 10/18/2017] [Indexed: 12/12/2022] Open
Abstract
Hepatitis B virus (HBV) is a major etiologic agent of acute and chronic hepatitis, and end-stage liver disease. Establishment of HBV infection, progression to persistency and pathogenesis are determined by viral and cellular factors, some of which remain still undefined. Key steps of HBV life cycle e.g., transformation of genomic viral DNA into transcriptionally active episomal DNA (cccDNA) or transcription of viral mRNAs from cccDNA, take place in the nucleus of infected cells and strongly depend on enzymatic activities provided by cellular proteins. In this regard, DNA damage response (DDR) pathways and some DDR proteins are being recognized as important factors regulating the infection. On one hand, HBV highjacks specific DDR proteins to successfully complete some of the steps of its life cycle. On the other hand, HBV subverts DDR pathways to presumably create a cellular environment that favours its replication. Direct consequences of these interactions are: HBV DNA integration into host chromosomal DNA, and accumulation of mutations in host chromosomal DNA that could eventually trigger carcinogenic processes, which would explain in part the incidence of hepatocellular carcinoma in chronically infected patients. Unravelling the interactions that HBV establishes with DDR pathways might help identify new molecular targets for therapeutic intervention.
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Affiliation(s)
- Andoni Gómez-Moreno
- Department of Molecular and Cellular Biology, Centro Nacional de Biotecnología-Consejo Superior de Investigaciones Científicas (CNB-CSIC), Darwin 3, 28049 Madrid, Spain.
| | - Urtzi Garaigorta
- Department of Molecular and Cellular Biology, Centro Nacional de Biotecnología-Consejo Superior de Investigaciones Científicas (CNB-CSIC), Darwin 3, 28049 Madrid, Spain.
- Centro de Investigación Biomédica en Red (CIBER) de Enfermedades Hepáticas y Digestivas (CIBERehd), 28029 Madrid, Spain.
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Zhou X, Shi H, Yang S, Sun P. An efficient rapid system for assaying HBx-mediated transactivation. Biotechnol Lett 2017; 39:1091-1099. [PMID: 28386736 DOI: 10.1007/s10529-017-2334-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2017] [Accepted: 03/30/2017] [Indexed: 02/05/2023]
Abstract
OBJECTIVES To develop a rapid and accurate assay system for screening inhibitors or enhancing agents targeting the transactivation capability of hepatitis B virus X protein (HBx) that activates cellular promoters in host cells to facilitate viral replication. RESULTS We constructed a new GFP-based reporter system which was different from a luciferase-based reporter system. Firstly, a FLAG-tagged HBx gene was inserted into an expression plasmid, resulting in plasmid pHBx. Next, HBx-FLAG was linked to EGFP by the internal ribosome entry site resulting in plasmid pHBxE. The transactivation effect of HBx-flag on cytomegalovirus (CMV) promoter was verified by EGFP expression using fluorescence quantitation and qPCR. Furthermore, the transactivation ability of the HBx gene was quantified by flow cytometry. Finally, this assay system was tested by known regulators of HBx including DDB1, ID1, and P53. As expected, the GFP reporter level in 293T cells changed with the increasing of HBx regulators. Furthermore, the system modeling the function of transactivation repressor in Hep3B, a HBV-integrated cell line. CONCLUSION Collectively, the GFP-based reporter system provides a rapid and accurate approach for analyzing transactivation ability of HBx.
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Affiliation(s)
- Xiaoling Zhou
- Stem Cell P2 Laboratory, Shantou University Medical College, Shantou, 515041, People's Republic of China
- The Center for Reproductive Medicine, Shantou University Medical College, Shantou, 515041, People's Republic of China
- Guangdong Provincial Key Laboratory of Infectious Diseases and Molecular Immunopathology, Shantou University Medical College, Shantou, 515041, People's Republic of China
| | - Haijun Shi
- Stem Cell P2 Laboratory, Shantou University Medical College, Shantou, 515041, People's Republic of China
- The Center for Reproductive Medicine, Shantou University Medical College, Shantou, 515041, People's Republic of China
- Guangdong Provincial Key Laboratory of Infectious Diseases and Molecular Immunopathology, Shantou University Medical College, Shantou, 515041, People's Republic of China
| | - Shaozhe Yang
- Stem Cell P2 Laboratory, Shantou University Medical College, Shantou, 515041, People's Republic of China
- The Center for Reproductive Medicine, Shantou University Medical College, Shantou, 515041, People's Republic of China
- Guangdong Provincial Key Laboratory of Infectious Diseases and Molecular Immunopathology, Shantou University Medical College, Shantou, 515041, People's Republic of China
| | - Pingnan Sun
- Stem Cell P2 Laboratory, Shantou University Medical College, Shantou, 515041, People's Republic of China.
- The Center for Reproductive Medicine, Shantou University Medical College, Shantou, 515041, People's Republic of China.
- Guangdong Provincial Key Laboratory of Infectious Diseases and Molecular Immunopathology, Shantou University Medical College, Shantou, 515041, People's Republic of China.
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Yan Z, Zeng J, Yu Y, Xiang K, Hu H, Zhou X, Gu L, Wang L, Zhao J, Young JAT, Gao L. HBVcircle: A novel tool to investigate hepatitis B virus covalently closed circular DNA. J Hepatol 2017; 66:1149-1157. [PMID: 28213165 DOI: 10.1016/j.jhep.2017.02.004] [Citation(s) in RCA: 57] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/26/2016] [Revised: 01/18/2017] [Accepted: 02/02/2017] [Indexed: 12/31/2022]
Abstract
BACKGROUND & AIMS Hepatitis B virus (HBV) covalently closed circular DNA (cccDNA) persists as a stable episome in infected hepatocytes and serves as a template for the transcription of all viral genes. Due to the narrow host range of HBV, the development of a robust mouse model that supports cccDNA-dependent viral replication is a key hurdle in the development of novel HBV therapeutics. This study aimed to develop a novel tool to investigate HBV cccDNA. METHODS Through minicircle technology, HBVcircle, a recombinant cccDNA, was easily generated and extracted from a genetically engineered E. coli strain. We characterized the performance of HBVcircle in cell culture by transfection and in immunocompetent mice by hydrodynamic injection (HDI). RESULTS We demonstrated that HBVcircle formed authentic cccDNA-like molecules in vitro in transiently transfected hepatic cells and in vivo in mouse liver after HDI. HBVcircle supported high levels and persistent HBV replication. In addition, we investigated different factors affecting HBV in vivo replication and persistence, including the host genetic background, vector design and dosage, viral genes and genotypes, and immune activation status. Furthermore, different classes of anti-HBV drugs were also assessed with the HBVcircle system. CONCLUSION Compared with previous reported HBV mouse models which employ other viral vectors to introduce overlength HBV genomes, viral gene expression and associated phenotypes are entirely driven by cccDNA-like viral genomes in the HBVcircle mouse model. Therefore, the HBVcircle is a close mimic of cccDNA, and it represents a novel tool for addressing HBV cccDNA related biological questions and for anti-HBV drug discovery. LAY SUMMARY To establish a mouse model that supports cccDNA-dependent transcription, a novel tool named HBVcircle, was developed with minicircle technology. HBVcircle formed authentic cccDNA-like molecules in hepatocytes, and supported high levels and persistent HBV replication in vivo. The HBVcircle is a close mimic of cccDNA, and it represents a novel tool for addressing HBV cccDNA related biological questions and for anti-HBV drug discovery.
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Affiliation(s)
- Zhipeng Yan
- Roche Innovation Center Shanghai, Shanghai 201203, China
| | - Jing Zeng
- Roche Innovation Center Shanghai, Shanghai 201203, China
| | - Youjun Yu
- Roche Innovation Center Shanghai, Shanghai 201203, China
| | - Kunlun Xiang
- Roche Innovation Center Shanghai, Shanghai 201203, China
| | - Hui Hu
- Roche Innovation Center Shanghai, Shanghai 201203, China
| | - Xue Zhou
- Roche Innovation Center Shanghai, Shanghai 201203, China
| | - Lili Gu
- Roche Innovation Center Shanghai, Shanghai 201203, China
| | - Li Wang
- Roche Innovation Center Shanghai, Shanghai 201203, China
| | - Jie Zhao
- Roche Innovation Center Shanghai, Shanghai 201203, China
| | | | - Lu Gao
- Roche Innovation Center Shanghai, Shanghai 201203, China.
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Identifying and Characterizing Interplay between Hepatitis B Virus X Protein and Smc5/6. Viruses 2017; 9:v9040069. [PMID: 28368357 PMCID: PMC5408675 DOI: 10.3390/v9040069] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2017] [Revised: 03/27/2017] [Accepted: 03/29/2017] [Indexed: 12/17/2022] Open
Abstract
Hepatitis B X protein (HBx) plays an essential role in the hepatitis B virus (HBV) replication cycle, but the function of HBx has been elusive until recently. It was recently shown that transcription from the HBV genome (covalently-closed circular DNA, cccDNA) is inhibited by the structural maintenance of chromosome 5/6 complex (Smc5/6), and that a key function of HBx is to redirect the DNA-damage binding protein 1 (DDB1) E3 ubiquitin ligase to target this complex for degradation. By doing so, HBx alleviates transcriptional repression by Smc5/6 and stimulates HBV gene expression. In this review, we discuss in detail how the interplay between HBx and Smc5/6 was identified and characterized. We also discuss what is known regarding the repression of cccDNA transcription by Smc5/6, the timing of HBx expression, and the potential role of HBx in promoting hepatocellular carcinoma (HCC).
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Kinoshita W, Ogura N, Watashi K, Wakita T. Host factor PRPF31 is involved in cccDNA production in HBV-replicating cells. Biochem Biophys Res Commun 2016; 482:638-644. [PMID: 27864147 DOI: 10.1016/j.bbrc.2016.11.085] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2016] [Accepted: 11/15/2016] [Indexed: 02/07/2023]
Abstract
Hepatitis B virus (HBV) covalently closed circular DNA (cccDNA) plays a central role in chronic HBV infection and replication, and is an important factor for HBV surface antigen loss indicating the endpoint of HBV treatment. However, there is a known problem that current anti-HBV drugs, including interferons and nucleos(t)ide analogues, reduce HBV replication but have a little or no effect on reducing cccDNA. Therefore, the development of new therapeutic agents is necessary to eradicate cccDNA. In this study, we identified pre-mRNA processing factor 31 (PRPF31) by siRNA screening as a factor associated with cccDNA. PRPF31 knockdown by siRNA decreased cccDNA formation without serious cytotoxicity. In rescue experiments, expression of siRNA-resistant PRPF31 recovered cccDNA formation. PRPF31 knockdown did not affect HBV core protein and HBV core DNA levels in HBV-replicating cells. Chromatin immunoprecipitation and immunoprecipitation assays revealed an association between PRPF31 and cccDNA. Furthermore, co-overexpression of PRPF31 and HBx enhanced cccDNA formation in HepAD38 cells. Taken together, the present findings suggest that the interaction between PRPF31 and HBx may be a novel target for anti-HBV treatment.
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Affiliation(s)
- Wataru Kinoshita
- Central Pharmaceutical Research Institute, Japan Tobacco Inc., Osaka, Japan.
| | - Naoki Ogura
- Central Pharmaceutical Research Institute, Japan Tobacco Inc., Osaka, Japan.
| | - Koichi Watashi
- Department of Virology II, National Institute of Infectious Diseases, Tokyo, Japan.
| | - Takaji Wakita
- Department of Virology II, National Institute of Infectious Diseases, Tokyo, Japan.
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Bagga S, Rawat S, Ajenjo M, Bouchard MJ. Hepatitis B virus (HBV) X protein-mediated regulation of hepatocyte metabolic pathways affects viral replication. Virology 2016; 498:9-22. [DOI: 10.1016/j.virol.2016.08.006] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2016] [Revised: 07/20/2016] [Accepted: 08/06/2016] [Indexed: 12/25/2022]
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Hepatitis B Virus Protein X Induces Degradation of Talin-1. Viruses 2016; 8:v8100281. [PMID: 27775586 PMCID: PMC5086613 DOI: 10.3390/v8100281] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2016] [Revised: 10/06/2016] [Accepted: 10/09/2016] [Indexed: 12/27/2022] Open
Abstract
In the infected human hepatocyte, expression of the hepatitis B virus (HBV) accessory protein X (HBx) is essential to maintain viral replication in vivo. HBx critically interacts with the host damaged DNA binding protein 1 (DDB1) and the associated ubiquitin ligase machinery, suggesting that HBx functions by inducing the degradation of host proteins. To identify such host proteins, we systematically analyzed the HBx interactome. One HBx interacting protein, talin-1 (TLN1), was proteasomally degraded upon HBx expression. Further analysis showed that TLN1 levels indeed modulate HBV transcriptional activity in an HBx-dependent manner. This indicates that HBx-mediated TLN1 degradation is essential and sufficient to stimulate HBV replication. Our data show that TLN1 can act as a viral restriction factor that suppresses HBV replication, and suggest that the HBx relieves this restriction by inducing TLN1 degradation.
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DDB1 Stimulates Viral Transcription of Hepatitis B Virus via HBx-Independent Mechanisms. J Virol 2016; 90:9644-9653. [PMID: 27535046 DOI: 10.1128/jvi.00977-16] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2016] [Accepted: 08/05/2016] [Indexed: 02/07/2023] Open
Abstract
HBx, a small regulatory protein of hepatitis B virus (HBV), augments viral DNA replication by stimulating viral transcription. Among numerous reported HBx-binding proteins, DDB1 has drawn attention, because DDB1 acts as a substrate receptor of the Cul4-DDB1 ubiquitin E3 ligase. Previous work reported that the DDB1-HBx interaction is indispensable for HBx-stimulated viral DNA replication, suggesting that the Cul4-DDB1 ubiquitin E3 ligase might target cellular restriction factors for ubiquitination and proteasomal degradation. To gain further insight into the DDB1-HBx interaction, we generated HBx mutants deficient for DDB1 binding (i.e., R96A, L98A, and G99A) and examined whether they support HBx-stimulated viral DNA replication. In contrast to data from previous reports, our results showed that the HBx mutants deficient for DDB1 binding supported viral DNA replication to nearly wild-type levels, revealing that the DDB1-HBx interaction is largely dispensable for HBx-stimulated viral DNA replication. Instead, we found that DDB1 directly stimulates viral transcription regardless of HBx expression. Through an HBV infection study, importantly, we demonstrated that DDB1 stimulates viral transcription from covalently closed circular DNA, a physiological template for viral transcription. Overall, we concluded that DDB1 stimulates viral transcription via a mechanism that does not involve an interaction with HBx. IMPORTANCE DDB1 constitutes a cullin-based ubiquitin E3 ligase, where DDB1 serves as an adaptor linking the cullin scaffold to the substrate receptor. Previous findings that the DDB1-binding ability of HBx is essential for HBx-stimulated viral DNA replication led to the hypothesis that HBx could downregulate host restriction factors that limit HBV replication through the cullin ubiquitin E3 ligase that requires the DDB1-HBx interaction. Consistent with this hypothesis, recent work identified Smc5/6 as a host restriction factor that is regulated by the viral cullin ubiquitin E3 ligase. In contrast, here we found that the DDB1-HBx interaction is largely dispensable for HBx-stimulated viral DNA replication. Instead, our results clearly showed that DDB1, regardless of HBx expression, enhances viral transcription. Overall, besides its role in the viral cullin ubiquitin E3 ligase, DDB1 itself stimulates viral transcription via HBx-independent mechanisms.
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