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Khaykelson D, Asor R, Zhao Z, Schlicksup CJ, Zlotnick A, Raviv U. Guanidine Hydrochloride-Induced Hepatitis B Virus Capsid Disassembly Hysteresis. Biochemistry 2024; 63:1543-1552. [PMID: 38787909 PMCID: PMC11191408 DOI: 10.1021/acs.biochem.4c00077] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2024] [Revised: 04/20/2024] [Accepted: 04/25/2024] [Indexed: 05/26/2024]
Abstract
Hepatitis B virus (HBV) displays remarkable self-assembly capabilities that interest the scientific community and biotechnological industries as HBV is leading to an annual mortality of up to 1 million people worldwide (especially in Africa and Southeast Asia). When the ionic strength is increased, hepatitis B virus-like particles (VLPs) can assemble from dimers of the first 149 residues of the HBV capsid protein core assembly domain (Cp149). Using solution small-angle X-ray scattering, we investigated the disassembly of the VLPs by titrating guanidine hydrochloride (GuHCl). Measurements were performed with and without 1 M NaCl, added either before or after titrating GuHCl. Fitting the scattering curves to a linear combination of atomic models of Cp149 dimer (the subunit) and T = 3 and T = 4 icosahedral capsids revealed the mass fraction of the dimer in each structure in all the titration points. Based on the mass fractions, the variation in the dimer-dimer association standard free energy was calculated as a function of added GuHCl, showing a linear relation between the interaction strength and GuHCl concentration. Using the data, we estimated the energy barriers for assembly and disassembly and the critical nucleus size for all of the assembly reactions. Extrapolating the standard free energy to [GuHCl] = 0 showed an evident hysteresis in the assembly process, manifested by differences in the dimer-dimer association standard free energy obtained for the disassembly reactions compared with the equivalent assembly reactions. Similar hysteresis was observed in the energy barriers for assembly and disassembly and the critical nucleus size. The results suggest that above 1.5 M, GuHCl disassembled the capsids by attaching to the protein and adding steric repulsion, thereby weakening the hydrophobic attraction.
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Affiliation(s)
- Daniel Khaykelson
- Institute
of Chemistry and the Center for Nanoscience and Nanotechnology, the Hebrew University of Jerusalem, Edmond J. Safra Campus, Givat Ram, Jerusalem 9190401, Israel
| | - Roi Asor
- Institute
of Chemistry and the Center for Nanoscience and Nanotechnology, the Hebrew University of Jerusalem, Edmond J. Safra Campus, Givat Ram, Jerusalem 9190401, Israel
| | - Zhongchao Zhao
- Department
of Molecular and Cellular Biochemistry, Indiana University, Bloomington, Indiana 47405, United States
| | - Christopher John Schlicksup
- Department
of Molecular and Cellular Biochemistry, Indiana University, Bloomington, Indiana 47405, United States
| | - Adam Zlotnick
- Department
of Molecular and Cellular Biochemistry, Indiana University, Bloomington, Indiana 47405, United States
| | - Uri Raviv
- Institute
of Chemistry and the Center for Nanoscience and Nanotechnology, the Hebrew University of Jerusalem, Edmond J. Safra Campus, Givat Ram, Jerusalem 9190401, Israel
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2
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Chung CY, Sun CP, Tao MH, Wu HL, Wang SH, Yeh SH, Zheng QB, Yuan Q, Xia NS, Ogawa K, Nakashima K, Suzuki T, Chen PJ. Major HBV splice variant encoding a novel protein important for infection. J Hepatol 2024; 80:858-867. [PMID: 38336347 DOI: 10.1016/j.jhep.2024.01.037] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/04/2023] [Revised: 01/16/2024] [Accepted: 01/23/2024] [Indexed: 02/12/2024]
Abstract
BACKGROUND & AIMS HBV expresses more than 10 spliced RNAs from the viral pregenomic RNA, but their functions remain elusive and controversial. To address the function of HBV spliced RNAs, we generated splicing-deficient HBV mutants and conducted experiments to assess the impact of these mutants on HBV infection. METHODS HepG2-NTCP cells, human hepatocyte chimeric FRG mice (hu-FRG mice), and serum from patients with chronic hepatitis B were used for experiments on HBV infection. Additionally, SHifter assays and cryo-electron microscopy were performed. RESULTS We found the infectivity of splicing-deficient HBV was decreased 100-1,000-fold compared with that of wild-type HBV in hu-FRG mice. Another mutant, A487C, which loses the most abundant spliced RNA (SP1), also exhibits severely impaired infectivity. SP1 hypothetically encodes a novel protein HBcSP1 (HBc-Cys) that lacks the C-terminal cysteine from full-length HBc. In the SHifter assay, HBcSP1 was detected in wild-type viral particles at a ratio of about 20-100% vs. conventional HBc, as well as in the serum of patients with chronic hepatitis B, but not in A487C particles. When infection was conducted with a shorter incubation time of 4-8 h at lower PEG concentrations in HepG2-NTCP cells, the entry of the A487C mutant was significantly slower. SP1 cDNA complementation of the A487C mutant succeeded in rescuing its infectivity in hu-FRG mice and HepG2-NTCP cells. Moreover, cryo-electron microscopy revealed a disulfide bond between HBc cysteine 183 and 48 in the HBc intradimer of the A487C capsid, leading to a locked conformation that disfavored viral entry in contrast to the wild-type capsid. CONCLUSIONS Prior studies unveiled the potential integration of the HBc-Cys protein into the HBV capsid. We confirmed the proposal and validated its identity and function during infection. IMPACT AND IMPLICATIONS HBV SP1 RNA encodes a novel HBc protein (HBcSP1) that lacks the C-terminal cysteine from conventional HBc (HBc-Cys). HBcSP1 was detected in cell culture-derived HBV and confirmed in patients with chronic infection by both immunological and chemical modification assays at 10-50% of capsid. The splicing-deficient mutant HBV (A487C) impaired infectivity in human hepatocyte chimeric mice and viral entry in the HepG2-NTCP cell line. Furthermore, these deficiencies of the splicing-deficient mutant could be rescued by complementation with the SP1-encoded protein HBcSP1. We confirmed and validated the identity and function of HBcSP1 during infection, building on the current model of HBV particles.
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Affiliation(s)
- Chen-Yen Chung
- National Taiwan University College of Medicine, Taipei, Taiwan
| | - Cheng-Pu Sun
- Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan
| | - Mi-Hua Tao
- Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan
| | - Hui-Lin Wu
- Hepatitis Research Center, National Taiwan University Hospital, Taipei, Taiwan
| | - Sheng-Han Wang
- Hepatitis Research Center, National Taiwan University Hospital, Taipei, Taiwan
| | - Shiou-Hwei Yeh
- National Taiwan University College of Medicine, Taipei, Taiwan; Hepatitis Research Center, National Taiwan University Hospital, Taipei, Taiwan
| | - Qing-Bing Zheng
- National Institute of Diagnostics and Vaccine Development in Infectious Diseases, School of Life Sciences, Xiamen University, Xiamen, P.R. China
| | - Quan Yuan
- National Institute of Diagnostics and Vaccine Development in Infectious Diseases, School of Life Sciences, Xiamen University, Xiamen, P.R. China
| | - Ning-Shao Xia
- National Institute of Diagnostics and Vaccine Development in Infectious Diseases, School of Life Sciences, Xiamen University, Xiamen, P.R. China
| | - Kenji Ogawa
- RIKEN Center for Sustainable Resource Science (CSRS), RIKEN, Wako, Saitama, Japan
| | | | | | - Pei-Jer Chen
- National Taiwan University College of Medicine, Taipei, Taiwan.
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3
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Feng Q, Saladin M, Wu C, Cao E, Zheng W, Zhang A, Bhardwaj P, Li X, Shen Q, Kapinos LE, Mariappan M, Lusk CP, Xiong Y, Lim RYH, Lin C. Channel width modulates the permeability of DNA origami based nuclear pore mimics. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.05.09.593438. [PMID: 38766144 PMCID: PMC11100828 DOI: 10.1101/2024.05.09.593438] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2024]
Abstract
Nucleoporins (nups) in the central channel of nuclear pore complexes (NPCs) form a selective barrier that suppresses the diffusion of most macromolecules while enabling rapid transport of nuclear transport receptors (NTRs) with bound cargos. The complex molecular interactions between nups and NTRs have been thought to underlie the gatekeeping function of the NPC. Recent studies have shown considerable variation in NPC diameter but how altering NPC diameter might impact the selective barrier properties remains unclear. Here, we build DNA nanopores with programmable diameters and nup arrangement to mimic NPCs of different diameters. We use hepatitis B virus (HBV) capsids as a model for large-size cargos. We find that Nup62 proteins form a dynamic cross-channel meshwork impermeable to HBV capsids when grafted on the interior of 60-nm wide nanopores but not in 79-nm pores, where Nup62 cluster locally. Furthermore, importing substantially changes the dynamics of Nup62 assemblies and facilitates the passage of HBV capsids through NPC mimics containing Nup62 and Nup153. Our study shows the transport channel width is critical to the permeability of nup barriers and underscores the role of NTRs in dynamically remodeling nup assemblies and mediating the nuclear entry of viruses.
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Affiliation(s)
- Qingzhou Feng
- Department of Cell Biology, Yale School of Medicine, USA
- Nanobiology Institute, Yale University, USA
| | | | - Chunxiang Wu
- Department of Biophysics and Biochemistry, Yale University, USA
| | - Eason Cao
- Department of Cell Biology, Yale School of Medicine, USA
- Nanobiology Institute, Yale University, USA
| | - Wei Zheng
- Department of Biophysics and Biochemistry, Yale University, USA
| | - Amy Zhang
- Department of Cell Biology, Yale School of Medicine, USA
- Nanobiology Institute, Yale University, USA
| | | | - Xia Li
- Department of Cell Biology, Yale School of Medicine, USA
| | - Qi Shen
- Department of Cell Biology, Yale School of Medicine, USA
- Nanobiology Institute, Yale University, USA
- Department of Biophysics and Biochemistry, Yale University, USA
| | | | - Malaiyalam Mariappan
- Department of Cell Biology, Yale School of Medicine, USA
- Nanobiology Institute, Yale University, USA
| | | | - Yong Xiong
- Department of Biophysics and Biochemistry, Yale University, USA
| | - Roderick Y. H. Lim
- Biozentrum, University of Basel, Switzerland
- Swiss Nanoscience Institute, University of Basel, Switzerland
| | - Chenxiang Lin
- Department of Cell Biology, Yale School of Medicine, USA
- Nanobiology Institute, Yale University, USA
- Department of Biomedical Engineering, Yale University, USA
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4
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Romero S, Unchwaniwala N, Evans EL, Eliceiri KW, Loeb DD, Sherer NM. Live Cell Imaging Reveals HBV Capsid Translocation from the Nucleus To the Cytoplasm Enabled by Cell Division. mBio 2023; 14:e0330322. [PMID: 36809075 PMCID: PMC10127671 DOI: 10.1128/mbio.03303-22] [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: 11/29/2022] [Accepted: 01/17/2023] [Indexed: 02/23/2023] Open
Abstract
Hepatitis B virus (HBV) capsid assembly is traditionally thought to occur predominantly in the cytoplasm, where the virus gains access to the virion egress pathway. To better define sites of HBV capsid assembly, we carried out single cell imaging of HBV Core protein (Cp) subcellular trafficking over time under conditions supporting genome packaging and reverse transcription in Huh7 hepatocellular carcinoma cells. Time-course analyses including live cell imaging of fluorescently tagged Cp derivatives showed Cp to accumulate in the nucleus at early time points (~24 h), followed by a marked re-distribution to the cytoplasm at 48 to 72 h. Nucleus-associated Cp was confirmed to be capsid and/or high-order assemblages using a novel dual label immunofluorescence strategy. Nuclear-to-cytoplasmic re-localization of Cp occurred predominantly during nuclear envelope breakdown in conjunction with cell division, followed by strong cytoplasmic retention of Cp. Blocking cell division resulted in strong nuclear entrapment of high-order assemblages. A Cp mutant, Cp-V124W, predicted to exhibit enhanced assembly kinetics, also first trafficked to the nucleus to accumulate at nucleoli, consistent with the hypothesis that Cp's transit to the nucleus is a strong and constitutive process. Taken together, these results provide support for the nucleus as an early-stage site of HBV capsid assembly, and provide the first dynamic evidence of cytoplasmic retention after cell division as a mechanism underpinning capsid nucleus-to-cytoplasm relocalization. IMPORTANCE Hepatitis B virus (HBV) is an enveloped, reverse-transcribing DNA virus that is a major cause of liver disease and hepatocellular carcinoma. Subcellular trafficking events underpinning HBV capsid assembly and virion egress remain poorly characterized. Here, we developed a combination of fixed and long-term (>24 h) live cell imaging technologies to study the single cell trafficking dynamics of the HBV Core Protein (Cp). We demonstrate that Cp first accumulates in the nucleus, and forms high-order structures consistent with capsids, with the predominant route of nuclear egress being relocalization to the cytoplasm during cell division in conjunction with nuclear membrane breakdown. Single cell video microscopy demonstrated unequivocally that Cp's localization to the nucleus is constitutive. This study represents a pioneering application of live cell imaging to study HBV subcellular transport, and demonstrates links between HBV Cp and the cell cycle.
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Affiliation(s)
- Sofia Romero
- McArdle Laboratory for Cancer Research (Department of Oncology), University of Wisconsin-Madison School of Medicine and Public Health, Madison, Wisconsin, USA
- Institute for Molecular Virology, University of Wisconsin-Madison, Madison, Wisconsin, USA
- Microbiology Doctoral Training Program, University of Wisconsin-Madison, Madison, Wisconsin, USA
- Carbone Cancer Center, University of Wisconsin-Madison School of Medicine and Public Health, Madison, Wisconsin, USA
| | - Nuruddin Unchwaniwala
- McArdle Laboratory for Cancer Research (Department of Oncology), University of Wisconsin-Madison School of Medicine and Public Health, Madison, Wisconsin, USA
- Institute for Molecular Virology, University of Wisconsin-Madison, Madison, Wisconsin, USA
- Carbone Cancer Center, University of Wisconsin-Madison School of Medicine and Public Health, Madison, Wisconsin, USA
| | - Edward L. Evans
- Laboratory for Optical and Computational Instrumentation, Center for Quantitative Cell Imaging, University of Wisconsin-Madison, Madison, Wisconsin, USA
- Morgridge Institute for Research, Madison, Wisconsin, USA
| | - Kevin W. Eliceiri
- Laboratory for Optical and Computational Instrumentation, Center for Quantitative Cell Imaging, University of Wisconsin-Madison, Madison, Wisconsin, USA
- Morgridge Institute for Research, Madison, Wisconsin, USA
| | - Daniel D. Loeb
- McArdle Laboratory for Cancer Research (Department of Oncology), University of Wisconsin-Madison School of Medicine and Public Health, Madison, Wisconsin, USA
- Carbone Cancer Center, University of Wisconsin-Madison School of Medicine and Public Health, Madison, Wisconsin, USA
| | - Nathan M. Sherer
- McArdle Laboratory for Cancer Research (Department of Oncology), University of Wisconsin-Madison School of Medicine and Public Health, Madison, Wisconsin, USA
- Institute for Molecular Virology, University of Wisconsin-Madison, Madison, Wisconsin, USA
- Carbone Cancer Center, University of Wisconsin-Madison School of Medicine and Public Health, Madison, Wisconsin, USA
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5
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Modeling HIV-1 nuclear entry with nucleoporin-gated DNA-origami channels. Nat Struct Mol Biol 2023; 30:425-435. [PMID: 36807645 PMCID: PMC10121901 DOI: 10.1038/s41594-023-00925-9] [Citation(s) in RCA: 14] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2022] [Accepted: 01/16/2023] [Indexed: 02/22/2023]
Abstract
Delivering the virus genome into the host nucleus through the nuclear pore complex (NPC) is pivotal in human immunodeficiency virus 1 (HIV-1) infection. The mechanism of this process remains mysterious owing to the NPC complexity and the labyrinth of molecular interactions involved. Here we built a suite of NPC mimics-DNA-origami-corralled nucleoporins with programmable arrangements-to model HIV-1 nuclear entry. Using this system, we determined that multiple cytoplasm-facing Nup358 molecules provide avid binding for capsid docking to the NPC. The nucleoplasm-facing Nup153 preferentially attaches to high-curvature regions of the capsid, positioning it for tip-leading NPC insertion. Differential capsid binding strengths of Nup358 and Nup153 constitute an affinity gradient that drives capsid penetration. Nup62 in the NPC central channel forms a barrier that viruses must overcome during nuclear import. Our study thus provides a wealth of mechanistic insight and a transformative toolset for elucidating how viruses like HIV-1 enter the nucleus.
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6
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Starr CA, Nair S, Huang SY, Hagan MF, Jacobson SC, Zlotnick A. Engineering Metastability into a Virus-like Particle to Enable Triggered Dissociation. J Am Chem Soc 2023; 145:2322-2331. [PMID: 36651799 PMCID: PMC10018796 DOI: 10.1021/jacs.2c10937] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
For a virus-like particle (VLP) to serve as a delivery platform, the VLP must be able to release its cargo in response to a trigger. Here, we use a chemical biology approach to destabilize a self-assembling capsid for a subsequent triggered disassembly. We redesigned the dimeric hepatitis B virus (HBV) capsid protein (Cp) with two differentially addressable cysteines, C150 for reversibly crosslinking the capsid and C124 to react with a destabilizing moiety. The resulting construct, Cp150-V124C, assembles into icosahedral, 120-dimer VLPs that spontaneously crosslink via the C-terminal C150, leaving C124 buried at a dimer-dimer interface. The VLP is driven into a metastable state when C124 is reacted with the bulky fluorophore, maleimidyl BoDIPY-FL. The resulting VLP is stable until exposed to modest, physiologically relevant concentrations of reducing agent. We observe dissociation with FRET relaxation of polarization, size exclusion chromatography, and resistive-pulse sensing. Dissociation is slow, minutes to hours, with a characteristic lag phase. Mathematical modeling based on the presence of a nucleation step predicts disassembly dynamics that are consistent with experimental observations. VLPs transfected into hepatoma cells show similar dissociation behavior. These results suggest a generalizable strategy for designing a VLP that can release its contents in an environmentally responsive reaction.
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Affiliation(s)
- Caleb A. Starr
- Molecular and Cellular Biochemistry, Indiana University, Bloomington, IN 47405 USA
| | - Smita Nair
- Molecular and Cellular Biochemistry, Indiana University, Bloomington, IN 47405 USA
- current address: Door Pharmaceuticals, Bloomington, IN 47401 USA
| | - Sheng-Yuan Huang
- Department of Chemistry, Indiana University, Bloomington, IN 47405 USA
| | - Michael F. Hagan
- Martin Fisher School of Physics, Brandeis University, Waltham, MA 02454 USA
| | | | - Adam Zlotnick
- Molecular and Cellular Biochemistry, Indiana University, Bloomington, IN 47405 USA
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7
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Pregenomic RNA Launch Hepatitis B Virus Replication System Facilitates the Mechanistic Study of Antiviral Agents and Drug-Resistant Variants on Covalently Closed Circular DNA Synthesis. J Virol 2022; 96:e0115022. [PMID: 36448800 PMCID: PMC9769369 DOI: 10.1128/jvi.01150-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/05/2022] Open
Abstract
Hepatitis B virus (HBV) replicates its genomic DNA by reverse transcription of an RNA intermediate, termed pregenomic RNA (pgRNA), within nucleocapsid. It had been shown that transfection of in vitro-transcribed pgRNA initiated viral replication in human hepatoma cells. We demonstrated here that viral capsids, single-stranded DNA, relaxed circular DNA (rcDNA) and covalently closed circular DNA (cccDNA) became detectable sequentially at 3, 6, 12, and 24 h post-pgRNA transfection into Huh7.5 cells. The levels of viral DNA replication intermediates and cccDNA peaked at 24 and 48 h post-pgRNA transfection, respectively. HBV surface antigen (HBsAg) became detectable in culture medium at day 4 posttransfection. Interestingly, the early robust viral DNA replication and cccDNA synthesis did not depend on the expression of HBV X protein (HBx), whereas HBsAg production was strictly dependent on viral DNA replication and expression of HBx, consistent with the essential role of HBx in the transcriptional activation of cccDNA minichromosomes. While the robust and synchronized HBV replication within 48 h post-pgRNA transfection is particularly suitable for the precise mapping of the HBV replication steps, from capsid assembly to cccDNA formation, targeted by distinct antiviral agents, the treatment of cells starting at 48 h post-pgRNA transfection allows the assessment of antiviral agents on mature nucleocapsid uncoating, cccDNA synthesis, and transcription, as well as viral RNA stability. Moreover, the pgRNA launch system could be used to readily assess the impacts of drug-resistant variants on cccDNA formation and other replication steps in the viral life cycle. IMPORTANCE Hepadnaviral pgRNA not only serves as a template for reverse transcriptional replication of viral DNA but also expresses core protein and DNA polymerase to support viral genome replication and cccDNA synthesis. Not surprisingly, cytoplasmic expression of duck hepatitis B virus pgRNA initiated viral replication leading to infectious virion secretion. However, HBV replication and antiviral mechanism were studied primarily in human hepatoma cells transiently or stably transfected with plasmid-based HBV replicons. The presence of large amounts of transfected HBV DNA or transgenes in cellular chromosomes hampered the robust analyses of HBV replication and cccDNA function. As demonstrated here, the pgRNA launch HBV replication system permits the accurate mapping of antiviral target and investigation of cccDNA biosynthesis and transcription using secreted HBsAg as a convenient quantitative marker. The effect of drug-resistant variants on viral capsid assembly, genome replication, and cccDNA biosynthesis and function can also be assessed using this system.
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8
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Invasion and Propagation of White Spot Syndrome Virus: Hijacking of the Cytoskeleton, Intracellular Transport Machinery, and Nuclear Import Transporters. J Virol 2022; 96:e0220521. [PMID: 35638850 DOI: 10.1128/jvi.02205-21] [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] [Indexed: 11/20/2022] Open
Abstract
The pathogenesis of white spot syndrome virus (WSSV) is largely unclear. In this study, we found that actin nucleation and clathrin-mediated endocytosis were recruited for internalization of WSSV into crayfish hematopoietic tissue (Hpt) cells. This internalization was followed by intracellular transport of the invading virions via endocytic vesicles and endosomes. After envelope fusion within endosomes, the penetrated nucleocapsids were transported along microtubules toward the periphery of the nuclear pores. Furthermore, the nuclear transporter CqImportin α1/β1, via binding of ARM repeat domain within CqImportin α1 to the nuclear localization sequences (NLSs) of viral cargoes and binding of CqImportin β1 to the nucleoporins CqNup35/62 with the action of CqRan for docking to nuclear pores, was hijacked for both targeting of the incoming nucleocapsids toward the nuclear pores and import of the expressed viral structural proteins containing NLS into the cell nucleus. Intriguingly, dysfunction of CqImportin α1/β1 resulted in significant accumulation of incoming nucleocapsids on the periphery of the Hpt cell nucleus, leading to substantially decreased introduction of the viral genome into the nucleus and remarkably reduced nuclear import of expressed viral structural proteins with NLS; both of these effects were accompanied by significantly inhibited viral propagation. Accordingly, the survival rate of crayfish post-WSSV challenge was significantly increased after dysfunction of CqImportin α1/β1, also showing significantly reduced viral propagation, and was induced either by gene silencing or by pharmacological blockade via dietary administration of ivermectin per os. Collectively, our findings improve our understanding of WSSV pathogenesis and support future antiviral designing against WSSV. IMPORTANCE As one of the largest animal DNA viruses, white spot syndrome virus (WSSV) has been causing severe economical loss in aquaculture due to the limited knowledge on WSSV pathogenesis for an antiviral strategy. We demonstrate that the actin cytoskeleton, endocytic vesicles, endosomes, and microtubules are hijacked for WSSV invasion; importantly, the nuclear transporter CqImportin α1/β1 together with CqRan were recruited, via binding of CqImportin β1 to the nucleoporins CqNup35/62, for both the nuclear pore targeting of the incoming nucleocapsids and the nuclear import of expressed viral structural proteins containing the nuclear localization sequences (NLSs). This is the first report that NLSs from both viral structure proteins and host factor are elaborately recruited together to facilitate WSSV infection. Our findings provide a novel explanation for WSSV pathogenesis involving systemic hijacking of host factors, which can be used for antiviral targeting against WSSV disease, such as the blockade of CqImportin α1/β1 with ivermectin.
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Bianca C, Sidhartha E, Tiribelli C, El-Khobar KE, Sukowati CHC. Role of hepatitis B virus in development of hepatocellular carcinoma: Focus on covalently closed circular DNA. World J Hepatol 2022; 14:866-884. [PMID: 35721287 PMCID: PMC9157711 DOI: 10.4254/wjh.v14.i5.866] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/30/2021] [Revised: 01/31/2022] [Accepted: 04/25/2022] [Indexed: 02/06/2023] Open
Abstract
Chronic infection with hepatitis B virus (HBV) remains a major global health problem, especially in developing countries. It may lead to prolonged liver damage, fibrosis, cirrhosis, and hepatocellular carcinoma. Persistent chronic HBV infection is related to host immune response and the stability of the covalently closed circular DNA (cccDNA) in human hepatocytes. In addition to being essential for viral transcription and replication, cccDNA is also suspected to play a role in persistent HBV infections or hepatitis relapses since cccDNA is very stable in non-dividing human hepatocytes. Understanding the pathogenicity and oncogenicity of HBV components would be essential in the development of new diagnostic tools and treatment strategies. This review summarizes the role and molecular mechanisms of HBV cccDNA in hepatocyte transformation and hepatocarcinogenesis and current efforts to its detection and targeting.
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Affiliation(s)
- Claryssa Bianca
- Department of Biomedicine, Indonesia International Institute for Life Sciences, Jakarta 13210, Indonesia
| | - Elizabeth Sidhartha
- Department of Biomedicine, Indonesia International Institute for Life Sciences, Jakarta 13210, Indonesia
| | - Claudio Tiribelli
- Centro Studi Fegato, Fondazione Italiana Fegato ONLUS, Trieste 34149, Italy
| | - Korri Elvanita El-Khobar
- Eijkman Center for Molecular Biology, National Research and Innovation Agency (BRIN), Jakarta 10340, Indonesia
| | - Caecilia H C Sukowati
- Centro Studi Fegato, Fondazione Italiana Fegato ONLUS, Trieste 34149, Italy
- Eijkman Center for Molecular Biology, National Research and Innovation Agency (BRIN), Jakarta 10340, Indonesia
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10
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Jacobs R, Singh P, Smith T, Arbuthnot P, Maepa MB. Prospects of viral vector-mediated delivery of sequences encoding anti-HBV designer endonucleases. Gene Ther 2022:10.1038/s41434-022-00342-5. [PMID: 35606493 DOI: 10.1038/s41434-022-00342-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2021] [Revised: 05/05/2022] [Accepted: 05/06/2022] [Indexed: 11/09/2022]
Abstract
Available treatment for chronic hepatitis B virus (HBV) infection offers modest functional curative efficacy. The viral replicative intermediate comprising covalently closed circular DNA (cccDNA) is responsible for persistent chronic HBV infection. Hence, current efforts have focused on developing therapies that disable cccDNA. Employing gene editing tools has emerged as an attractive strategy, with the end goal of establishing permanently inactivated cccDNA. Although anti-HBV designer nucleases are effective in vivo, none has yet progressed to clinical trial. Lack of safe and efficient delivery systems remains the limiting factor. Several vectors may be used to deliver anti-HBV gene editor-encoding sequences, with viral vectors being at the forefront. Despite the challenges associated with packaging large gene editor-encoding sequences into viral vectors, advancement in the field is overcoming such limitations. Translation of viral vector-mediated gene editing against HBV to clinical application is within reach. This review discusses the prospects of delivering HBV targeted designer nucleases using viral vectors.
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Affiliation(s)
- Ridhwaanah Jacobs
- Wits/SAMRC Antiviral Gene Therapy Research Unit, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Prashika Singh
- Wits/SAMRC Antiviral Gene Therapy Research Unit, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Tiffany Smith
- Wits/SAMRC Antiviral Gene Therapy Research Unit, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Patrick Arbuthnot
- Wits/SAMRC Antiviral Gene Therapy Research Unit, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Mohube Betty Maepa
- Wits/SAMRC Antiviral Gene Therapy Research Unit, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa.
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11
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Harati Taji Z, Bielytskyi P, Shein M, Sani MA, Seitz S, Schütz AK. Transient RNA Interactions Leave a Covalent Imprint on a Viral Capsid Protein. J Am Chem Soc 2022; 144:8536-8550. [PMID: 35512333 PMCID: PMC9121876 DOI: 10.1021/jacs.1c12439] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
The hepatitis B virus (HBV) is the leading cause of persistent liver infections. Its DNA-based genome is synthesized through reverse transcription of an RNA template inside the assembled capsid shell. In addition to the structured assembly domain, the capsid protein harbors a C-terminal extension that mediates both the enclosure of RNA during capsid assembly and the nuclear entry of the capsid during infection. The arginine-rich motifs within this extension, though common to many viruses, have largely escaped atomic-scale investigation. Here, we leverage solution and solid-state nuclear magnetic resonance spectroscopy at ambient and cryogenic temperatures, under dynamic nuclear polarization signal enhancement, to investigate the organization of the genome within the capsid. Transient interactions with phosphate groups of the RNA backbone confine the arginine-rich motifs to the interior capsid space. While no secondary structure is induced in the C-terminal extension, interactions with RNA counteract the formation of a disulfide bond, which covalently tethers this peptide arm onto the inner capsid surface. Electrostatic and covalent contributions thus compete in the spatial regulation of capsid architecture. This disulfide switch represents a coupling mechanism between the structured assembly domain of the capsid and the enclosed nucleic acids. In particular, it enables the redox-dependent regulation of the exposure of the C-terminal extension on the capsid surface, which is required for nuclear uptake of the capsid. Phylogenetic analysis of capsid proteins from hepadnaviruses points toward a function of this switch in the persistence of HBV infections.
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Affiliation(s)
- Zahra Harati Taji
- Bavarian NMR Center, Department of Chemistry, Technical University of Munich, Garching 85748, Germany.,Institute of Structural Biology, Helmholtz Zentrum München, Neuherberg 85764, Germany
| | - Pavlo Bielytskyi
- Bavarian NMR Center, Department of Chemistry, Technical University of Munich, Garching 85748, Germany.,Institute of Structural Biology, Helmholtz Zentrum München, Neuherberg 85764, Germany
| | - Mikhail Shein
- Bavarian NMR Center, Department of Chemistry, Technical University of Munich, Garching 85748, Germany.,Institute of Structural Biology, Helmholtz Zentrum München, Neuherberg 85764, Germany
| | - Marc-Antoine Sani
- School of Chemistry, Bio21 Institute, University of Melbourne, Melbourne, Victoria 3010, Australia
| | - Stefan Seitz
- Department of Infectious Diseases, Molecular Virology, University of Heidelberg, Heidelberg 69120, Germany.,Division of Virus-Associated Carcinogenesis (F170), German Cancer Research Center (DKFZ), Heidelberg 69120, Germany
| | - Anne K Schütz
- Bavarian NMR Center, Department of Chemistry, Technical University of Munich, Garching 85748, Germany.,Institute of Structural Biology, Helmholtz Zentrum München, Neuherberg 85764, Germany
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12
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Khan IW, Dad Ullah MU, Choudhry M, Ali MJ, Ali MA, Lam SLK, Shah PA, Kaur SP, Lau DTY. Novel Therapies of Hepatitis B and D. Microorganisms 2021; 9:2607. [PMID: 34946209 PMCID: PMC8707465 DOI: 10.3390/microorganisms9122607] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2021] [Revised: 12/03/2021] [Accepted: 12/07/2021] [Indexed: 02/05/2023] Open
Abstract
Hepatitis B virus (HBV) infection is a global public health issue and is a major cause of cirrhosis and hepatocellular carcinoma (HCC). Hepatitis D virus (HDV) requires the hepatitis B surface antigen (HBsAg) to replicate. The eradication of HBV, therefore, can also cure HDV. The current therapies for chronic hepatitis B and D are suboptimal and cannot definitely cure the viruses. In order to achieve functional or complete cure of these infections, novel therapeutic agents that target the various sites of the viral replicative cycle are necessary. Furthermore, novel immunomodulatory agents are also essential to achieve viral clearance. Many of these new promising compounds such as entry inhibitors, covalently closed circular DNA (cccDNA) inhibitors, small interfering RNAs (siRNAs), capsid assembly modulators and nucleic acid polymers are in various stages of clinical developments. In this review article, we provided a comprehensive overview of the structure and lifecycle of HBV, the limitations of the current therapies and a summary of the novel therapeutic agents for both HDV and HBV infection.
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Affiliation(s)
- Iman Waheed Khan
- Liver Center, Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02115, USA; (I.W.K.); (M.U.D.U.); (M.C.); (M.J.A.); (M.A.A.); (S.P.K.)
| | - Mati Ullah Dad Ullah
- Liver Center, Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02115, USA; (I.W.K.); (M.U.D.U.); (M.C.); (M.J.A.); (M.A.A.); (S.P.K.)
| | - Mina Choudhry
- Liver Center, Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02115, USA; (I.W.K.); (M.U.D.U.); (M.C.); (M.J.A.); (M.A.A.); (S.P.K.)
| | - Mukarram Jamat Ali
- Liver Center, Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02115, USA; (I.W.K.); (M.U.D.U.); (M.C.); (M.J.A.); (M.A.A.); (S.P.K.)
| | - Muhammad Ashar Ali
- Liver Center, Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02115, USA; (I.W.K.); (M.U.D.U.); (M.C.); (M.J.A.); (M.A.A.); (S.P.K.)
| | - Sam L. K. Lam
- Liver Center, Department of Medicine, Department of Pharmacy, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02115, USA;
| | - Pir Ahmad Shah
- Department of Internal Medicine, University of Texas, San Antonio, TX 78229, USA;
| | - Satinder Pal Kaur
- Liver Center, Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02115, USA; (I.W.K.); (M.U.D.U.); (M.C.); (M.J.A.); (M.A.A.); (S.P.K.)
| | - Daryl T. Y. Lau
- Liver Center, Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02115, USA; (I.W.K.); (M.U.D.U.); (M.C.); (M.J.A.); (M.A.A.); (S.P.K.)
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13
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Mani N, Cole AG, Phelps JR, Ardzinski A, Burns R, Chiu T, Cuconati A, Dorsey BD, Evangelista E, Fan K, Guo F, Harasym TO, Kadhim S, Kowalski R, Kultgen SG, Lee ACH, Li AH, Majeski SA, Miller A, Pasetka C, Reid SP, Rijnbrand R, Micolochick Steuer HM, Stever K, Tang S, Teng X, Wang X, Sofia MJ. Preclinical characterization of AB-506, an inhibitor of HBV replication targeting the viral core protein. Antiviral Res 2021; 197:105211. [PMID: 34826506 DOI: 10.1016/j.antiviral.2021.105211] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2021] [Revised: 11/19/2021] [Accepted: 11/22/2021] [Indexed: 02/06/2023]
Abstract
AB-506, a small-molecule inhibitor targeting the HBV core protein, inhibits viral replication in vitro (HepAD38 cells: EC50 of 0.077 μM, CC50 > 25 μM) and in vivo (HBV mouse model: ∼3.0 log10 reductions in serum HBV DNA compared to the vehicle control). Binding of AB-506 to HBV core protein accelerates capsid assembly and inhibits HBV pgRNA encapsidation. Furthermore, AB-506 blocks cccDNA establishment in HBV-infected HepG2-hNTCP-C4 cells and primary human hepatocytes, leading to inhibition of viral RNA, HBsAg, and HBeAg production (EC50 from 0.64 μM to 1.92 μM). AB-506 demonstrated activity across HBV genotypes A-H and maintains antiviral activity against nucleos(t)ide analog-resistant variants in vitro. Evaluation of AB-506 against a panel of core variants showed that T33N/Q substitutions results in >200-fold increase in EC50 values, while L30F, L37Q, and I105T substitutions showed an 8 to 20-fold increase in EC50 values in comparison to the wild-type. In vitro combinations of AB-506 with NAs or an RNAi agent were additive to moderately synergistic. AB-506 exhibits good oral bioavailability, systemic exposure, and higher liver to plasma ratios in rodents, a pharmacokinetic profile supporting clinical development for chronic hepatitis B.
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Affiliation(s)
- Nagraj Mani
- Arbutus Biopharma Inc., 701 Veterans Circle, Warminster, PA, 18974, USA.
| | - Andrew G Cole
- Arbutus Biopharma Inc., 701 Veterans Circle, Warminster, PA, 18974, USA
| | - Janet R Phelps
- Arbutus Biopharma Inc., 701 Veterans Circle, Warminster, PA, 18974, USA
| | - Andrzej Ardzinski
- Arbutus Biopharma Inc., 701 Veterans Circle, Warminster, PA, 18974, USA
| | - Robbin Burns
- Arbutus Biopharma Inc., 701 Veterans Circle, Warminster, PA, 18974, USA
| | - Tim Chiu
- Arbutus Biopharma Inc., 701 Veterans Circle, Warminster, PA, 18974, USA
| | - Andrea Cuconati
- Arbutus Biopharma Inc., 701 Veterans Circle, Warminster, PA, 18974, USA
| | - Bruce D Dorsey
- Arbutus Biopharma Inc., 701 Veterans Circle, Warminster, PA, 18974, USA
| | - Ellen Evangelista
- Arbutus Biopharma Inc., 701 Veterans Circle, Warminster, PA, 18974, USA
| | - Kristi Fan
- Arbutus Biopharma Inc., 701 Veterans Circle, Warminster, PA, 18974, USA
| | - Fang Guo
- Arbutus Biopharma Inc., 701 Veterans Circle, Warminster, PA, 18974, USA
| | - Troy O Harasym
- Arbutus Biopharma Inc., 701 Veterans Circle, Warminster, PA, 18974, USA
| | - Salam Kadhim
- Arbutus Biopharma Inc., 701 Veterans Circle, Warminster, PA, 18974, USA
| | - Roseann Kowalski
- Arbutus Biopharma Inc., 701 Veterans Circle, Warminster, PA, 18974, USA
| | - Steven G Kultgen
- Arbutus Biopharma Inc., 701 Veterans Circle, Warminster, PA, 18974, USA
| | - Amy C H Lee
- Arbutus Biopharma Inc., 701 Veterans Circle, Warminster, PA, 18974, USA
| | - Alice H Li
- Arbutus Biopharma Inc., 701 Veterans Circle, Warminster, PA, 18974, USA
| | - Sara A Majeski
- Arbutus Biopharma Inc., 701 Veterans Circle, Warminster, PA, 18974, USA
| | - Angela Miller
- Arbutus Biopharma Inc., 701 Veterans Circle, Warminster, PA, 18974, USA
| | - Chris Pasetka
- Arbutus Biopharma Inc., 701 Veterans Circle, Warminster, PA, 18974, USA
| | - Stephen P Reid
- Arbutus Biopharma Inc., 701 Veterans Circle, Warminster, PA, 18974, USA
| | - Rene Rijnbrand
- Arbutus Biopharma Inc., 701 Veterans Circle, Warminster, PA, 18974, USA
| | | | - Kim Stever
- Arbutus Biopharma Inc., 701 Veterans Circle, Warminster, PA, 18974, USA
| | - Sunny Tang
- Arbutus Biopharma Inc., 701 Veterans Circle, Warminster, PA, 18974, USA
| | - Xiaowei Teng
- Arbutus Biopharma Inc., 701 Veterans Circle, Warminster, PA, 18974, USA
| | - Xiaohe Wang
- Arbutus Biopharma Inc., 701 Veterans Circle, Warminster, PA, 18974, USA
| | - Michael J Sofia
- Arbutus Biopharma Inc., 701 Veterans Circle, Warminster, PA, 18974, USA
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14
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Niklasch M, Zimmermann P, Nassal M. The Hepatitis B Virus Nucleocapsid-Dynamic Compartment for Infectious Virus Production and New Antiviral Target. Biomedicines 2021; 9:1577. [PMID: 34829806 PMCID: PMC8615760 DOI: 10.3390/biomedicines9111577] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2021] [Revised: 10/19/2021] [Accepted: 10/21/2021] [Indexed: 12/11/2022] Open
Abstract
Hepatitis B virus (HBV) is a small enveloped DNA virus which replicates its tiny 3.2 kb genome by reverse transcription inside an icosahedral nucleocapsid, formed by a single ~180 amino acid capsid, or core, protein (Cp). HBV causes chronic hepatitis B (CHB), a severe liver disease responsible for nearly a million deaths each year. Most of HBV's only seven primary gene products are multifunctional. Though less obvious than for the multi-domain polymerase, P protein, this is equally crucial for Cp with its multiple roles in the viral life-cycle. Cp provides a stable genome container during extracellular phases, allows for directed intracellular genome transport and timely release from the capsid, and subsequent assembly of new nucleocapsids around P protein and the pregenomic (pg) RNA, forming a distinct compartment for reverse transcription. These opposing features are enabled by dynamic post-transcriptional modifications of Cp which result in dynamic structural alterations. Their perturbation by capsid assembly modulators (CAMs) is a promising new antiviral concept. CAMs inappropriately accelerate assembly and/or distort the capsid shell. We summarize the functional, biochemical, and structural dynamics of Cp, and discuss the therapeutic potential of CAMs based on clinical data. Presently, CAMs appear as a valuable addition but not a substitute for existing therapies. However, as part of rational combination therapies CAMs may bring the ambitious goal of a cure for CHB closer to reality.
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Affiliation(s)
| | | | - Michael Nassal
- Internal Medicine II/Molecular Biology, University Hospital Freiburg, Hugstetter Str. 55, D-79106 Freiburg, Germany; (M.N.); (P.Z.)
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15
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Van Damme E, Vanhove J, Severyn B, Verschueren L, Pauwels F. The Hepatitis B Virus Interactome: A Comprehensive Overview. Front Microbiol 2021; 12:724877. [PMID: 34603251 PMCID: PMC8482013 DOI: 10.3389/fmicb.2021.724877] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2021] [Accepted: 08/17/2021] [Indexed: 12/19/2022] Open
Abstract
Despite the availability of a prophylactic vaccine, chronic hepatitis B (CHB) caused by the hepatitis B virus (HBV) is a major health problem affecting an estimated 292 million people globally. Current therapeutic goals are to achieve functional cure characterized by HBsAg seroclearance and the absence of HBV-DNA after treatment cessation. However, at present, functional cure is thought to be complicated due to the presence of covalently closed circular DNA (cccDNA) and integrated HBV-DNA. Even if the episomal cccDNA is silenced or eliminated, it remains unclear how important the high level of HBsAg that is expressed from integrated HBV DNA is for the pathology. To identify therapies that could bring about high rates of functional cure, in-depth knowledge of the virus' biology is imperative to pinpoint mechanisms for novel therapeutic targets. The viral proteins and the episomal cccDNA are considered integral for the control and maintenance of the HBV life cycle and through direct interaction with the host proteome they help create the most optimal environment for the virus whilst avoiding immune detection. New HBV-host protein interactions are continuously being identified. Unfortunately, a compendium of the most recent information is lacking and an interactome is unavailable. This article provides a comprehensive review of the virus-host relationship from viral entry to release, as well as an interactome of cccDNA, HBc, and HBx.
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Affiliation(s)
- Ellen Van Damme
- Janssen Research & Development, Janssen Pharmaceutical Companies, Beerse, Belgium
| | - Jolien Vanhove
- Janssen Research & Development, Janssen Pharmaceutical Companies, Beerse, Belgium.,Early Discovery Biology, Charles River Laboratories, Beerse, Belgium
| | - Bryan Severyn
- Janssen Research & Development, Janssen Pharmaceutical Companies, Springhouse, PA, United States
| | - Lore Verschueren
- Janssen Research & Development, Janssen Pharmaceutical Companies, Beerse, Belgium
| | - Frederik Pauwels
- Janssen Research & Development, Janssen Pharmaceutical Companies, Beerse, Belgium
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16
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Campos-Valdez M, Monroy-Ramírez HC, Armendáriz-Borunda J, Sánchez-Orozco LV. Molecular Mechanisms during Hepatitis B Infection and the Effects of the Virus Variability. Viruses 2021; 13:v13061167. [PMID: 34207116 PMCID: PMC8235420 DOI: 10.3390/v13061167] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2021] [Revised: 06/10/2021] [Accepted: 06/11/2021] [Indexed: 12/16/2022] Open
Abstract
The immunopathogenesis and molecular mechanisms involved during a hepatitis B virus (HBV) infection have made the approaches for research complex, especially concerning the patients’ responses in the course of the early acute stage. The study of molecular bases involved in the viral clearance or persistence of the infection is complicated due to the difficulty to detect patients at the most adequate points of the disease, especially in the time lapse between the onset of the infection and the viral emergence. Despite this, there is valuable data obtained from animal and in vitro models, which have helped to clarify some aspects of the early immune response against HBV infection. The diversity of the HBV (genotypes and variants) has been proven to be associated not only with the development and outcome of the disease but also with the response to treatments. That is why factors involved in the virus evolution need to be considered while studying hepatitis B infection. This review brings together some of the published data to try to explain the immunological and molecular mechanisms involved in the different stages of the infection, clinical outcomes, viral persistence, and the impact of the variants of HBV in these processes.
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Affiliation(s)
- Marina Campos-Valdez
- Centro Universitario de Ciencias de la Salud, Departamento de Biología Molecular y Genómica, Instituto de Biología Molecular en Medicina, Universidad de Guadalajara, Guadalajara 44340, Jalisco, México; (M.C.-V.); (H.C.M.-R.); (J.A.-B.)
| | - Hugo C. Monroy-Ramírez
- Centro Universitario de Ciencias de la Salud, Departamento de Biología Molecular y Genómica, Instituto de Biología Molecular en Medicina, Universidad de Guadalajara, Guadalajara 44340, Jalisco, México; (M.C.-V.); (H.C.M.-R.); (J.A.-B.)
| | - Juan Armendáriz-Borunda
- Centro Universitario de Ciencias de la Salud, Departamento de Biología Molecular y Genómica, Instituto de Biología Molecular en Medicina, Universidad de Guadalajara, Guadalajara 44340, Jalisco, México; (M.C.-V.); (H.C.M.-R.); (J.A.-B.)
- Escuela de Medicina y Ciencias de la Salud, Tecnológico de Monterrey, Campus Guadalajara, Zapopan 45201, Jalisco, México
| | - Laura V. Sánchez-Orozco
- Centro Universitario de Ciencias de la Salud, Departamento de Biología Molecular y Genómica, Instituto de Biología Molecular en Medicina, Universidad de Guadalajara, Guadalajara 44340, Jalisco, México; (M.C.-V.); (H.C.M.-R.); (J.A.-B.)
- Correspondence: ; Tel.: +52-33-3954-5677
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17
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AlBurtamani N, Paul A, Fassati A. The Role of Capsid in the Early Steps of HIV-1 Infection: New Insights into the Core of the Matter. Viruses 2021; 13:v13061161. [PMID: 34204384 PMCID: PMC8234406 DOI: 10.3390/v13061161] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2021] [Revised: 06/10/2021] [Accepted: 06/14/2021] [Indexed: 01/27/2023] Open
Abstract
In recent years, major advances in research and experimental approaches have significantly increased our knowledge on the role of the HIV-1 capsid in the virus life cycle, from reverse transcription to integration and gene expression. This makes the capsid protein a good pharmacological target to inhibit HIV-1 replication. This review covers our current understanding of the role of the viral capsid in the HIV-1 life cycle and its interaction with different host factors that enable reverse transcription, trafficking towards the nucleus, nuclear import and integration into host chromosomes. It also describes different promising small molecules, some of them in clinical trials, as potential targets for HIV-1 therapy.
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18
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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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19
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Regulation of Hepatitis B Virus Replication by Cyclin Docking Motifs in Core Protein. J Virol 2021; 95:JVI.00230-21. [PMID: 33789995 DOI: 10.1128/jvi.00230-21] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2021] [Accepted: 03/27/2021] [Indexed: 12/16/2022] Open
Abstract
Hepatitis B virus (HBV) capsid or core protein (HBc) consists of an N-terminal domain (NTD) and a C-terminal domain (CTD) connected by a short linker peptide. Dynamic phosphorylation and dephosphorylation of HBc regulate its multiple functions in capsid assembly and viral replication. The cellular cyclin-dependent kinase 2 (CDK2) plays a major role in HBc phosphorylation and, furthermore, is incorporated into the viral capsid, accounting for most of the "endogenous kinase" activity associated with the capsid. The packaged CDK2 is thought to play a role in phosphorylating HBc to trigger nucleocapsid disassembly (uncoating), an essential step during viral infection. However, little is currently known on how CDK2 is recruited and packaged into the capsid. We have now identified three RXL motifs in the HBc NTD known as cyclin docking motifs (CDMs), which mediate the interactions of various CDK substrates/regulators with CDK/cyclin complexes. Mutations of the CDMs in the HBc NTD reduced CTD phosphorylation and diminished CDK2 packaging into the capsid. Also, the CDM mutations showed little effects on capsid assembly and pregenomic RNA (pgRNA) packaging but impaired the integrity of mature nucleocapsids. Furthermore, the CDM mutations blocked covalently closed circular DNA (CCC DNA) formation during infection while having no effect on or enhancing CCC DNA formation via intracellular amplification. These results indicate that the HBc NTD CDMs play a role in CDK2 recruitment and packaging, which, in turn, is important for productive infection.IMPORTANCE Hepatitis B virus (HBV) is an important global human pathogen and persistently infects hundreds of millions of people, who are at high risk of cirrhosis and liver cancer. HBV capsid packages a host cell protein kinase, the cyclin-dependent kinase 2 (CDK2), which is thought to be required to trigger disassembly of the viral nucleocapsid during infection by phosphorylating the capsid protein, a prerequisite for successful infection. We have identified docking sites on the capsid protein for recruiting CDK2, in complex with its cyclin partner, to facilitate capsid protein phosphorylation and CDK2 packaging. Mutations of these docking sites reduced capsid protein phosphorylation, impaired CDK2 packaging into HBV capsids, and blocked HBV infection. These results provide novel insights regarding CDK2 packaging into HBV capsids and the role of CDK2 in HBV infection and should facilitate the development of antiviral drugs that target the HBV capsid protein.
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20
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Tabasi M, Nombela I, Janssens J, Lahousse AP, Christ F, Debyser Z. Role of Transportin-SR2 in HIV-1 Nuclear Import. Viruses 2021; 13:829. [PMID: 34064404 PMCID: PMC8147801 DOI: 10.3390/v13050829] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2021] [Revised: 04/29/2021] [Accepted: 05/02/2021] [Indexed: 12/14/2022] Open
Abstract
The HIV replication cycle depends on the interaction of viral proteins with proteins of the host. Unraveling host-pathogen interactions during the infection is of great importance for understanding the pathogenesis and the development of antiviral therapies. To date HIV uncoating and nuclear import are the most debated steps of the HIV-1 replication cycle. Despite numerous studies during past decades, there is still much controversy with respect to the identity and the role of viral and host factors involved in these processes. In this review, we provide a comprehensive overview on the role of transportin-SR2 as a host cell factor during active nuclear transport.
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Affiliation(s)
| | | | | | | | | | - Zeger Debyser
- Laboratory for Molecular Virology and Gene Therapy, Department of Pharmaceutical and Pharmacological Sciences, KU Leuven, 3000 Leuven, Flanders, Belgium; (M.T.); (I.N.); (J.J.); (A.P.L.); (F.C.)
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21
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Hu J, Tang L, Cheng J, Zhou T, Li Y, Chang J, Zhao Q, Guo JT. Hepatitis B virus nucleocapsid uncoating: biological consequences and regulation by cellular nucleases. Emerg Microbes Infect 2021; 10:852-864. [PMID: 33870849 PMCID: PMC8812769 DOI: 10.1080/22221751.2021.1919034] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Upon infection of hepatocyte, Hepatitis B virus (HBV) genomic DNA in nucleocapsid is transported into the nucleus and converted into a covalently closed circular (ccc) DNA to serve as the template for transcription of viral RNAs. Viral DNA in the cytoplasmic progeny nucleocapsid is another resource to fuel cccDNA amplification. Apparently, nucleocapsid disassembly, or viral genomic DNA uncoating, is an essential step for cccDNA synthesis from both de novo infection and intracellular amplification pathways, and has a potential to activate DNA sensors and induce an innate immune response in infected hepatocytes. However, where and how the nucleocapsid disassembly occurs is not well understood. The work reported herein showed that the enhanced disassembly of progeny mature nucleocapsids in the cytoplasm supported cccDNA intracellular amplification, but failed to activate the cGAS-STING-mediated innate immune response in hepatocytes. Interestingly, while expression of a cytoplasmic exonuclease TREX1 in human hepatoma cells supporting HBV replication significantly reduced the amounts of cccDNA as well as its precursor, deproteinized relaxed circular (rc) DNA, expression of TREX1 in sodium taurocholate cotransporting polypeptide-expressing human hepatoma cells did not inhibit cccDNA synthesis from de novo HBV infection. The results from this cytoplasmic nuclease protection assay imply that the disassembly of progeny mature nucleocapsids and removal of viral DNA polymerase covalently linked to the 5′ end of minus strand of rcDNA take place in the cytoplasm. On the contrary, the disassembly of virion-derived nucleocapsids during de novo infection may occur at a different subcellular compartment and possibly via distinct mechanisms.
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Affiliation(s)
- Jin Hu
- Department of Experimental Medicine, Baruch S. Blumberg Institute, Doylestown, PA, USA.,Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, People's Republic of China
| | - Liudi Tang
- Department of Experimental Medicine, Baruch S. Blumberg Institute, Doylestown, PA, USA.,Microbiology and Immunology Graduate Program, Drexel University College of Medicine, Philadelphia, PA, USA
| | - Junjun Cheng
- Department of Experimental Medicine, Baruch S. Blumberg Institute, Doylestown, PA, USA
| | - Tianlun Zhou
- Department of Experimental Medicine, Baruch S. Blumberg Institute, Doylestown, PA, USA
| | - Yuhuan Li
- Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, People's Republic of China
| | - Jinhong Chang
- Department of Experimental Medicine, Baruch S. Blumberg Institute, Doylestown, PA, USA
| | - Qiong Zhao
- Department of Experimental Medicine, Baruch S. Blumberg Institute, Doylestown, PA, USA
| | - Ju-Tao Guo
- Department of Experimental Medicine, Baruch S. Blumberg Institute, Doylestown, PA, USA
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22
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Abstract
Hepatitis B virus (HBV) core protein (Cp) can be found in the nucleus and cytoplasm of infected hepatocytes; however, it preferentially segregates to a specific compartment correlating with disease status. Regulation of this intracellular partitioning of Cp remains obscure. In this paper, we report that cellular compartments are filled and vacated by Cp in a time- and concentration-dependent manner in both transfections and infections. At early times after transfection, Cp, in a dimeric state, preferentially localizes to the nucleolus. Later, the nucleolar compartment is emptied and Cp progresses to being predominantly nuclear, with a large fraction of the protein in an assembled state. Nuclear localization is followed by cell-wide distribution, and then Cp becomes exclusively cytoplasmic. The same trend in Cp movement is seen during an infection. Putative nucleolar retention signals have been identified and appear to be structure dependent. Export of Cp from the nucleus involves the CRM1 exportin. Time-dependent flux can be recapitulated by modifying Cp concentration, suggesting transitions are regulated by reaching a threshold concentration.
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23
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Marchetti AL, Guo H. New Insights on Molecular Mechanism of Hepatitis B Virus Covalently Closed Circular DNA Formation. Cells 2020; 9:cells9112430. [PMID: 33172220 PMCID: PMC7694973 DOI: 10.3390/cells9112430] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2020] [Revised: 11/03/2020] [Accepted: 11/04/2020] [Indexed: 12/15/2022] Open
Abstract
The chronic factor of the Hepatitis B Virus (HBV), specifically the covalently closed circular DNA (cccDNA), is a highly stable and active viral episomal genome established in the livers of chronic hepatitis B patients as a constant source of disease. Being able to target and eliminate cccDNA is the end goal for a genuine cure for HBV. Yet how HBV cccDNA is formed from the viral genomic relaxed circular DNA (rcDNA) and by what host factors had been long-standing research questions. It is generally acknowledged that HBV hijacks cellular functions to turn the open circular DNA conformation of rcDNA into cccDNA through DNA repair mechanisms. With great efforts from the HBV research community, there have been several recent leaps in our understanding of cccDNA formation. It is our goal in this review to analyze the recent reports showing evidence of cellular factor's involvement in the molecular pathway of cccDNA biosynthesis.
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Affiliation(s)
- Alexander L. Marchetti
- Department of Microbiology and Immunology, School of Medicine, Indiana University, Indianapolis, IN 46202, USA;
- Cancer Virology Program, Hillman Cancer Center, School of Medicine, University of Pittsburgh, Pittsburgh, PA 15213, USA
| | - Haitao Guo
- Cancer Virology Program, Hillman Cancer Center, School of Medicine, University of Pittsburgh, Pittsburgh, PA 15213, USA
- Department of Microbiology and Molecular Genetics, University of Pittsburgh, Pittsburgh, PA 15213, USA
- Correspondence:
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24
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Dandri M, Petersen J. cccDNA Maintenance in Chronic Hepatitis B - Targeting the Matrix of Viral Replication. Infect Drug Resist 2020; 13:3873-3886. [PMID: 33149632 PMCID: PMC7605611 DOI: 10.2147/idr.s240472] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2020] [Accepted: 10/02/2020] [Indexed: 12/11/2022] Open
Abstract
Chronic hepatitis B is a numerically important cause of cirrhosis and hepatocellular carcinoma, despite an effective prophylactic vaccine and well-tolerated and effective oral antivirals. Both the incapacity of the immune system to clear hepatitis B virus (HBV) infection and the unique replication strategies adopted by HBV are considered key determinants of HBV chronicity. In this regard, the formation of the HBV DNA minichromosome, the covalently closed circular DNA (cccDNA), in the nucleus of infected hepatocytes, is essential not only for the production of all viral proteins but also for HBV persistence even after long-term antiviral therapy. Licensed polymerase inhibitors target the HBV reverse transcriptase activity, control the disease with long-term therapy but fail to eliminate the cccDNA. Consequently, the production of viral RNAs and proteins, including the hepatitis B surface antigen (HBsAg), is not abolished. Novel therapeutic efforts that are in the pipeline for early clinical trials explore novel targets and molecules. Such therapeutic efforts focus on achieving a functional cure, which is defined by the loss of HBsAg and undetectable HBV DNA levels in serum. Since a true cure of HBV infection requires the elimination of the cccDNA from infected cells, comprehension of the mechanisms implicated in cccDNA biogenesis, regulation and stability appears necessary to achieve HBV eradication. In this review, we will summarize the state of knowledge on cccDNA metabolism, focusing on insights suggesting potential weak points of the cccDNA that may be key for the development of therapeutic approaches and design of clinical trials aiming at lowering cccDNA loads and activity.
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Affiliation(s)
- Maura Dandri
- Department of Internal Medicine, University Medical Center Hamburg - Eppendorf, Hamburg, Germany.,German Center for Infection Research (DZIF), Hamburg-Luebeck-Borstel-Riems Site, Germany
| | - Joerg Petersen
- Institute for Interdisciplinary Medicine, Asklepios Klinik St Georg, University of Hamburg, Hamburg, Germany
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25
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Magnius L, Mason WS, Taylor J, Kann M, Glebe D, Dény P, Sureau C, Norder H, Ictv Report Consortium. ICTV Virus Taxonomy Profile: Hepadnaviridae. J Gen Virol 2020; 101:571-572. [PMID: 32416744 PMCID: PMC7414443 DOI: 10.1099/jgv.0.001415] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
The family Hepadnaviridae comprises small enveloped viruses with a partially double-stranded DNA genome of 3.0–3.4 kb. All family members express three sets of proteins (preC/C, polymerase and preS/S) and replication involves reverse transcription within nucleocapsids in the cytoplasm of hepatocytes. Hepadnaviruses are hepatotropic and infections may be transient or persistent. There are five genera: Parahepadnavirus, Metahepadnavirus, Herpetohepadnavirus, Avihepadnavirus and Orthohepadnavirus. This is a summary of the International Committee on Taxonomy of Viruses (ICTV) Report on the family Hepadnaviridae, which is available at ictv.global/report/hepadnaviridae.
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Affiliation(s)
- Lars Magnius
- Ulf Lundahl´s Foundation, 10061 Stockholm, Sweden
| | | | - John Taylor
- Fox Chase Cancer Center, Philadelphia, PA 19111, USA
| | - Michael Kann
- Department of Infectious Diseases, Institute of Biomedicine, Sahlgrenska Academy, University of Gothenburg, 41345 Gothenburg, Sweden
| | - Dieter Glebe
- Institute of Medical Virology, National Reference Centre for Hepatitis B and D Viruses, Justus-Liebig-University Giessen, German Centre for Infection Research (DZIF), Giessen, Germany
| | - Paul Dény
- Centre de Recherches en Cancérologie de Lyon, INSERM U1052, UMR CNRS 5286, Team Hepatocarcinogenesis and Viral Infection, Lyon, France
| | - Camille Sureau
- Institut National de la Transfusion Sanguine (INTS), CNRS-INSERM U1134, Paris, France
| | - Heléne Norder
- Department of Infectious Diseases, Institute of Biomedicine, Sahlgrenska Academy, University of Gothenburg, 41345 Gothenburg, Sweden
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26
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Rashidi S, Farhadi L, Ghasemi F, Sheikhesmaeili F, Mohammadi A. The potential role of HLA-G in the pathogenesis of HBV infection: Immunosuppressive or immunoprotective? INFECTION GENETICS AND EVOLUTION 2020; 85:104580. [PMID: 33022425 DOI: 10.1016/j.meegid.2020.104580] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/09/2020] [Revised: 09/20/2020] [Accepted: 10/01/2020] [Indexed: 02/07/2023]
Abstract
The non-classical human leukocyte antigens (HLA)-G could be generally considered as a potent tolerogenic molecule, which modulates immune responses. HLA-G due to the immunosuppressive properties may play an important role in the pathogenesis of infections related to the liver. HLA-G may display two distinct activities in the pathological conditions so that it could be protective in the autoimmune and inflammatory diseases or could be suppressive of the immune system in the infections or cancers. HLA-G might be used as a novel therapeutic target for liver diseases in the future. Indeed, new therapeutic agents targeting HLA-G expression or antibodies which block HLA-G activity are being developed and tested. However, further consideration of the HLA-G function in liver disease is required. This review aims to summarize the role of HLA-G in the liver of patients with HBV infection.
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Affiliation(s)
- Saadyeh Rashidi
- Cellular and Molecular Research Center, Research Institute for Health Development, Kurdistan University of Medical Sciences, Sanandaj, Iran
| | - Leila Farhadi
- Cellular and Molecular Research Center, Research Institute for Health Development, Kurdistan University of Medical Sciences, Sanandaj, Iran
| | - Faezeh Ghasemi
- Blood Transfusion Research Center, High Institute for Research and Education in Transfusion Medicine, Tehran, Iran
| | - Farshad Sheikhesmaeili
- Liver and Digestive Research Center, Research Institute for Health Development, Kurdistan University of Medical Sciences, Sanandaj, Iran
| | - Asadollah Mohammadi
- Cellular and Molecular Research Center, Research Institute for Health Development, Kurdistan University of Medical Sciences, Sanandaj, Iran.
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27
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Chakraborty A, Ko C, Henning C, Lucko A, Harris JM, Chen F, Zhuang X, Wettengel JM, Roessler S, Protzer U, McKeating JA. Synchronised infection identifies early rate-limiting steps in the hepatitis B virus life cycle. Cell Microbiol 2020; 22:e13250. [PMID: 32799415 PMCID: PMC7611726 DOI: 10.1111/cmi.13250] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2020] [Revised: 07/15/2020] [Accepted: 07/27/2020] [Indexed: 12/11/2022]
Abstract
Hepatitis B virus (HBV) is an enveloped DNA virus that contains a partially double-stranded relaxed circular (rc) DNA. Upon infection, rcDNA is delivered to the nucleus where it is repaired to covalently closed circular (ccc) DNA that serves as the transcription template for all viral RNAs. Our understanding of HBV particle entry dynamics and host pathways regulating intracellular virus trafficking and cccDNA formation is limited. The discovery of sodium taurocholate co-transporting peptide (NTCP) as the primary receptor allows studies on these early steps in viral life cycle. We employed a synchronised infection protocol to quantify HBV entry kinetics. HBV attachment to cells at 4°C is independent of NTCP, however, subsequent particle uptake is NTCP-dependent and reaches saturation at 12 h post-infection. HBV uptake is clathrin- and dynamin dependent with actin and tubulin playing a role in the first 6 h of infection. Cellular fractionation studies demonstrate HBV DNA in the nucleus within 6 h of infection and cccDNA was first detected at 24 h post-infection. Our studies show the majority (83%) of cell bound particles enter HepG2-NTCP cells, however, only a minority (<1%) of intracellular rcDNA was converted to cccDNA, highlighting this as a rate-limiting in establishing infection in vitro. This knowledge highlights the deficiencies in our in vitro cell culture systems and will inform the design and evaluation of physiologically relevant models that support efficient HBV replication.
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Affiliation(s)
- Anindita Chakraborty
- Institute of Virology, Technical University of Munich, School of Medicine/Helmholtz Zentrum München, Munich, Germany.,Technical University of Munich, Institute for Advanced Study, Munich, Germany
| | - Chunkyu Ko
- Institute of Virology, Technical University of Munich, School of Medicine/Helmholtz Zentrum München, Munich, Germany
| | - Christin Henning
- Institute of Virology, Technical University of Munich, School of Medicine/Helmholtz Zentrum München, Munich, Germany
| | - Aaron Lucko
- Institute of Virology, Technical University of Munich, School of Medicine/Helmholtz Zentrum München, Munich, Germany
| | - James M Harris
- Nuffield Department of Medicine, University of Oxford, Oxford, UK
| | - Fuwang Chen
- Institute of Virology, Technical University of Munich, School of Medicine/Helmholtz Zentrum München, Munich, Germany
| | - Xiaodong Zhuang
- Nuffield Department of Medicine, University of Oxford, Oxford, UK
| | - Jochen M Wettengel
- Institute of Virology, Technical University of Munich, School of Medicine/Helmholtz Zentrum München, Munich, Germany
| | - Stephanie Roessler
- Institute of Pathology, University Hospital Heidelberg, Heidelberg, Germany
| | - Ulrike Protzer
- Institute of Virology, Technical University of Munich, School of Medicine/Helmholtz Zentrum München, Munich, Germany.,Technical University of Munich, Institute for Advanced Study, Munich, Germany.,German Center for Infection Research (DZIF), Munich, Germany
| | - Jane A McKeating
- Nuffield Department of Medicine, University of Oxford, Oxford, UK
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28
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Intracellular Trafficking of HBV Particles. Cells 2020; 9:cells9092023. [PMID: 32887393 PMCID: PMC7563130 DOI: 10.3390/cells9092023] [Citation(s) in RCA: 45] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2020] [Revised: 08/31/2020] [Accepted: 09/02/2020] [Indexed: 12/15/2022] Open
Abstract
The human hepatitis B virus (HBV), that is causative for more than 240 million cases of chronic liver inflammation (hepatitis), is an enveloped virus with a partially double-stranded DNA genome. After virion uptake by receptor-mediated endocytosis, the viral nucleocapsid is transported towards the nuclear pore complex. In the nuclear basket, the nucleocapsid disassembles. The viral genome that is covalently linked to the viral polymerase, which harbors a bipartite NLS, is imported into the nucleus. Here, the partially double-stranded DNA genome is converted in a minichromosome-like structure, the covalently closed circular DNA (cccDNA). The DNA virus HBV replicates via a pregenomic RNA (pgRNA)-intermediate that is reverse transcribed into DNA. HBV-infected cells release apart from the infectious viral parrticle two forms of non-infectious subviral particles (spheres and filaments), which are assembled by the surface proteins but lack any capsid and nucleic acid. In addition, naked capsids are released by HBV replicating cells. Infectious viral particles and filaments are released via multivesicular bodies; spheres are secreted by the classic constitutive secretory pathway. The release of naked capsids is still not fully understood, autophagosomal processes are discussed. This review describes intracellular trafficking pathways involved in virus entry, morphogenesis and release of (sub)viral particles.
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29
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Viswanathan U, Mani N, Hu Z, Ban H, Du Y, Hu J, Chang J, Guo JT. Targeting the multifunctional HBV core protein as a potential cure for chronic hepatitis B. Antiviral Res 2020; 182:104917. [PMID: 32818519 DOI: 10.1016/j.antiviral.2020.104917] [Citation(s) in RCA: 60] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2020] [Revised: 08/08/2020] [Accepted: 08/10/2020] [Indexed: 12/14/2022]
Abstract
The core (capsid) protein of hepatitis B virus (HBV) is the building block of nucleocapsids where viral DNA reverse transcriptional replication takes place and mediates virus-host cell interaction important for the persistence of HBV infection. The pleiotropic role of core protein (Cp) in HBV replication makes it an attractive target for antiviral therapies of chronic hepatitis B, a disease that affects more than 257 million people worldwide without a cure. Recent clinical studies indicate that core protein allosteric modulators (CpAMs) have a great promise as a key component of hepatitis B curative therapies. Particularly, it has been demonstrated that modulation of Cp dimer-dimer interactions by several chemical series of CpAMs not only inhibit nucleocapsid assembly and viral DNA replication, but also induce the disassembly of double-stranded DNA-containing nucleocapsids to prevent the synthesis of cccDNA. Moreover, the different chemotypes of CpAMs modulate Cp assembly by interaction with distinct amino acid residues at the HAP pocket between Cp dimer-dimer interfaces, which results in the assembly of Cp dimers into either non-capsid Cp polymers (type I CpAMs) or empty capsids with distinct physical property (type II CpAMs). The different CpAMs also differentially modulate Cp metabolism and subcellular distribution, which may impact cccDNA metabolism and host antiviral immune responses, the critical factors for the cure of chronic HBV infection. This review article highlights the recent research progress on the structure and function of core protein in HBV replication cycle, the mode of action of CpAMs, as well as the current status and perspectives on the discovery and development of core protein-targeting antivirals. This article forms part of a symposium in Antiviral Research on "Wide-ranging immune and direct-acting antiviral approaches to curing HBV and HDV infections."
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Affiliation(s)
- Usha Viswanathan
- Baruch S. Blumberg Institute, 3805 Old Easton Road, Doylestown, PA, 18902, USA
| | - Nagraj Mani
- Arbutus Biopharma Inc., 701 Veterans Circle, Warminster, PA, 18974, USA
| | - Zhanying Hu
- Baruch S. Blumberg Institute, 3805 Old Easton Road, Doylestown, PA, 18902, USA
| | - Haiqun Ban
- Baruch S. Blumberg Institute, 3805 Old Easton Road, Doylestown, PA, 18902, USA
| | - Yanming Du
- Baruch S. Blumberg Institute, 3805 Old Easton Road, Doylestown, PA, 18902, USA
| | - Jin Hu
- Baruch S. Blumberg Institute, 3805 Old Easton Road, Doylestown, PA, 18902, USA
| | - Jinhong Chang
- Baruch S. Blumberg Institute, 3805 Old Easton Road, Doylestown, PA, 18902, USA
| | - Ju-Tao Guo
- Baruch S. Blumberg Institute, 3805 Old Easton Road, Doylestown, PA, 18902, USA.
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30
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Makbul C, Nassal M, Böttcher B. Slowly folding surface extension in the prototypic avian hepatitis B virus capsid governs stability. eLife 2020; 9:e57277. [PMID: 32795390 PMCID: PMC7455244 DOI: 10.7554/elife.57277] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2020] [Accepted: 08/13/2020] [Indexed: 12/12/2022] Open
Abstract
Hepatitis B virus (HBV) is an important but difficult to study human pathogen. Most basics of the hepadnaviral life-cycle were unraveled using duck HBV (DHBV) as a model although DHBV has a capsid protein (CP) comprising ~260 rather than ~180 amino acids. Here we present high-resolution structures of several DHBV capsid-like particles (CLPs) determined by electron cryo-microscopy. As for HBV, DHBV CLPs consist of a dimeric α-helical frame-work with protruding spikes at the dimer interface. A fundamental new feature is a ~ 45 amino acid proline-rich extension in each monomer replacing the tip of the spikes in HBV CP. In vitro, folding of the extension takes months, implying a catalyzed process in vivo. DHBc variants lacking a folding-proficient extension produced regular CLPs in bacteria but failed to form stable nucleocapsids in hepatoma cells. We propose that the extension domain acts as a conformational switch with differential response options during viral infection.
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Affiliation(s)
- Cihan Makbul
- Julius Maximilian University of Würzburg, Department of Biochemistry and Rudolf Virchow CentreWürzburgGermany
| | - Michael Nassal
- University Hospital Freiburg, Internal Medicine 2/Molecular BiologyFreiburgGermany
| | - Bettina Böttcher
- Julius Maximilian University of Würzburg, Department of Biochemistry and Rudolf Virchow CentreWürzburgGermany
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31
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Wettengel JM, Burwitz BJ. Innovative HBV Animal Models Based on the Entry Receptor NTCP. Viruses 2020; 12:E828. [PMID: 32751581 PMCID: PMC7472226 DOI: 10.3390/v12080828] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2020] [Revised: 07/24/2020] [Accepted: 07/27/2020] [Indexed: 02/07/2023] Open
Abstract
Hepatitis B is a major global health problem, with an estimated 257 million chronically infected patients and almost 1 million deaths per year. The causative agent is hepatitis B virus (HBV), a small, enveloped, partially double-stranded DNA virus. HBV has a strict species specificity, naturally infecting only humans and chimpanzees. Sodium taurocholate co-transporting polypeptide (NTCP), a bile acid transporter expressed on hepatocytes, has been shown to be one of the key factors in HBV infection, playing a crucial role in the HBV entry process in vitro and in vivo. Variations in the amino acid sequence of NTCP can inhibit HBV infection and, therefore, contributes, in part, to the species barrier. This discovery has revolutionized the search for novel animal models of HBV. Indeed, it was recently shown that variations in the amino acid sequence of NTCP represent the sole species barrier for HBV infection in macaques. Here, we review what is known about HBV entry through the NTCP receptor and highlight how this knowledge has been harnessed to build new animal models for the study of HBV pathogenesis and curative therapies.
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Affiliation(s)
- Jochen M. Wettengel
- Institute of Virology, Technische Universität München/Helmholtz Zentrum München, Trogerstr. 30, 81675 Munich, Germany;
- Vaccine & Gene Therapy Institute, Oregon Health & Science University, 505 N.W. 185th Avenue Beaverton, Tanasbourne, OR 97006, USA
| | - Benjamin J. Burwitz
- Vaccine & Gene Therapy Institute, Oregon Health & Science University, 505 N.W. 185th Avenue Beaverton, Tanasbourne, OR 97006, USA
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32
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Phosphorylation of the Arginine-Rich C-Terminal Domains of the Hepatitis B Virus (HBV) Core Protein as a Fine Regulator of the Interaction between HBc and Nucleic Acid. Viruses 2020; 12:v12070738. [PMID: 32650547 PMCID: PMC7412469 DOI: 10.3390/v12070738] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2020] [Revised: 07/02/2020] [Accepted: 07/03/2020] [Indexed: 02/08/2023] Open
Abstract
The morphogenesis of Hepatitis B Virus (HBV) viral particles is nucleated by the oligomerization of HBc protein molecules, resulting in the formation of an icosahedral capsid shell containing the replication-competent nucleoprotein complex made of the viral polymerase and the pre-genomic RNA (pgRNA). HBc is a phospho-protein containing two distinct domains acting together throughout the viral replication cycle. The N-terminal domain, (residues 1–140), shown to self-assemble, is linked by a short flexible domain to the basic C-terminal domain (residues 150–183) that interacts with nucleic acids (NAs). In addition, the C-terminal domain contains a series of phospho-acceptor residues that undergo partial phosphorylation and de-phosphorylation during virus replication. This highly dynamic process governs the homeostatic charge that is essential for capsid stability, pgRNA packaging and to expose the C-terminal domain at the surface of the particles for cell trafficking. In this review, we discuss the roles of the N-terminal and C-terminal domains of HBc protein during HBV morphogenesis, focusing on how the C-terminal domain phosphorylation dynamics regulate its interaction with nucleic acids throughout the assembly and maturation of HBV particles.
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33
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Hepatitis B Virus Core Protein Domains Essential for Viral Capsid Assembly in a Cellular Context. J Mol Biol 2020; 432:3802-3819. [PMID: 32371046 DOI: 10.1016/j.jmb.2020.04.026] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2020] [Revised: 04/25/2020] [Accepted: 04/28/2020] [Indexed: 02/07/2023]
Abstract
Hepatitis B virus (HBV) core protein (HBc) is essential to the formation of the HBV capsid. HBc contains two domains: the N-terminal domain corresponding to residues 1-140 essential to form the icosahedral shell and the C-terminal domain corresponding to a basic and phosphorylated peptide, and required for DNA replication. The role of these two domains for HBV capsid assembly was essentially studied in vitro with HBc purified from mammalian or non-mammalian cell lysates, but their respective role in living cells remains to be clarified. We therefore investigated the assembly of the HBV capsid in Huh7 cells by combining fluorescence lifetime imaging microscopy/Förster's resonance energy transfer, fluorescence correlation spectroscopy and transmission electron microscopy approaches. We found that wild-type HBc forms oligomers early after transfection and at a sub-micromolar concentration. These oligomers are homogeneously diffused throughout the cell. We quantified a stoichiometry ranging from ~170 to ~230 HBc proteins per oligomer, consistent with the visualization of eGFP-containingHBV capsid shaped as native capsid particles by transmission electron microscopy. In contrast, no assembly was observed when HBc-N-terminal domain was expressed. This highlights the essential role of the C-terminal domain to form capsid in mammalian cells. Deletion of either the third helix or of the 124-135 residues of HBc had a dramatic impact on the assembly of the HBV capsid, inducing the formation of mis-assembled oligomers and monomers, respectively. This study shows that our approach using fluorescent derivatives of HBc is an innovative method to investigate HBV capsid formation.
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34
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Wang YX, Niklasch M, Liu T, Wang Y, Shi B, Yuan W, Baumert TF, Yuan Z, Tong S, Nassal M, Wen YM. Interferon-inducible MX2 is a host restriction factor of hepatitis B virus replication. J Hepatol 2020; 72:865-876. [PMID: 31863794 DOI: 10.1016/j.jhep.2019.12.009] [Citation(s) in RCA: 50] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/14/2019] [Revised: 11/27/2019] [Accepted: 12/02/2019] [Indexed: 02/06/2023]
Abstract
BACKGROUND & AIMS Non-cytolytic cure of HBV-infected hepatocytes by cytokines, including type I interferons (IFNs), is of importance for resolving acute and chronic infection. However, as IFNs stimulate hundreds of genes, those most relevant for HBV suppression remain largely unknown. Amongst them are the large myxovirus resistance (Mx) GTPases. Human MX1 (or MxA) is active against many RNA viruses, while MX2 (or MxB) was recently found to restrict HIV-1, HCV, and herpesviruses. Herein, we investigated the anti-HBV activity of MX2. METHODS The potential anti-HBV activity of MX2 and functional variants were assessed in transfected and HBV-infected hepatoma cells and primary human hepatocytes, employing multiple assays to analyze the synthesis and decay of HBV nucleic acids. The specific roles of MX2 in IFN-α-driven inhibition of HBV transcription and replication were assessed by MX2-specific shRNA interference (RNAi). RESULTS Both MX2 alone and IFN-α substantially inhibited HBV replication, due to significant deceleration of the synthesis and slight acceleration of the turnover of viral RNA. RNAi knockdown of MX2 significantly reduced the inhibitory effects of IFN-α. Strikingly, MX2 inhibited HBV infection by reducing covalently closed circular DNA (cccDNA), most likely by indirectly impairing the conversion of relaxed circular DNA to cccDNA rather than by destabilizing existing cccDNA. Various mutations affecting the GTPase activity and oligomerization status reduced MX2's anti-HBV activity. CONCLUSION MX2 is an important IFN-α inducible effector that decreases HBV RNA levels but can also potently inhibit HBV infection by indirectly impairing cccDNA formation. MX2 likely has the potential for therapeutic applications aimed at curing HBV infection by eliminating cccDNA. LAY SUMMARY This study shows that the protein MX2, which is induced by interferon-α, has important anti-hepatitis B virus (HBV) effector functions. MX2 can reduce the amount of covalently closed circular DNA, which is the form of DNA that HBV uses to maintain viral persistence within hepatocytes. MX2 also reduces HBV RNA levels by downregulating synthesis of viral RNA. MX2 likely represents a novel intrinsic HBV inhibitor that could have therapeutic potential, as well as being useful for improving our understanding of the complex biology of HBV and the antiviral mechanisms of interferon-α.
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Affiliation(s)
- Yong-Xiang Wang
- Key Laboratory of Medical Molecular Virology (MOE/NHC/CAMS), School of Basic Medical Sciences, Shanghai Medical College, Fudan University, 200032 Shanghai, China.
| | - Matthias Niklasch
- University Hospital Freiburg, Department of Internal Medicine II/Molecular Biology, 79106 Freiburg, Germany
| | - Tiantian Liu
- Key Laboratory of Medical Molecular Virology (MOE/NHC/CAMS), School of Basic Medical Sciences, Shanghai Medical College, Fudan University, 200032 Shanghai, China
| | - Yang Wang
- Key Laboratory of Medical Molecular Virology (MOE/NHC/CAMS), School of Basic Medical Sciences, Shanghai Medical College, Fudan University, 200032 Shanghai, China
| | - Bisheng Shi
- Shanghai Public Health Clinical Center, Shanghai Medical College, Fudan University, 201508 Shanghai, China
| | - Wenjie Yuan
- Key Laboratory of Medical Molecular Virology (MOE/NHC/CAMS), School of Basic Medical Sciences, Shanghai Medical College, Fudan University, 200032 Shanghai, China
| | - Thomas F Baumert
- Pôle Hépato-Digestif, Unité d'Hépatologie, Hôpitaux Universitaires de Strasbourg, Nouvel Hôpital Civil, 67091 Strasbourg, France; Université de Strasbourg, 67000 Strasbourg, France; Unité Inserm 1110, 67000 Strasbourg, France
| | - Zhenghong Yuan
- Key Laboratory of Medical Molecular Virology (MOE/NHC/CAMS), School of Basic Medical Sciences, Shanghai Medical College, Fudan University, 200032 Shanghai, China
| | - Shuping Tong
- Key Laboratory of Medical Molecular Virology (MOE/NHC/CAMS), School of Basic Medical Sciences, Shanghai Medical College, Fudan University, 200032 Shanghai, China
| | - Michael Nassal
- University Hospital Freiburg, Department of Internal Medicine II/Molecular Biology, 79106 Freiburg, Germany
| | - Yu-Mei Wen
- Key Laboratory of Medical Molecular Virology (MOE/NHC/CAMS), School of Basic Medical Sciences, Shanghai Medical College, Fudan University, 200032 Shanghai, China
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Dandri M. Epigenetic modulation in chronic hepatitis B virus infection. Semin Immunopathol 2020; 42:173-185. [PMID: 32185454 PMCID: PMC7174266 DOI: 10.1007/s00281-020-00780-6] [Citation(s) in RCA: 52] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2019] [Accepted: 01/08/2020] [Indexed: 02/06/2023]
Abstract
The human hepatitis B virus (HBV) is a small-enveloped DNA virus causing acute and chronic hepatitis. Despite the existence of an effective prophylactic vaccine and the strong capacity of approved antiviral drugs to suppress viral replication, chronic HBV infection (CHB) continues to be a major health burden worldwide. Both the inability of the immune system to resolve CHB and the unique replication strategy employed by HBV, which forms a stable viral covalently closed circular DNA (cccDNA) minichromosome in the hepatocyte nucleus, enable infection persistence. Knowledge of the complex network of interactions that HBV engages with its host is still limited but accumulating evidence indicates that epigenetic modifications occurring both on the cccDNA and on the host genome in the course of infection are essential to modulate viral activity and likely contribute to pathogenesis and cancer development. Thus, a deeper understanding of epigenetic regulatory processes may open new venues to control and eventually cure CHB. This review summarizes major findings in HBV epigenetic research, focusing on the epigenetic mechanisms regulating cccDNA activity and the modifications determined in infected host cells and tumor liver tissues.
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Affiliation(s)
- Maura Dandri
- I. Department of Internal Medicine, Center for Internal Medicine, University Medical Center Hamburg-Eppendorf, Martinistr. 52, 20246, Hamburg, Germany.
- German Center for Infection Research (DZIF), Hamburg-Lübeck-Borstel-Riems Site, Hamburg, Germany.
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Luo J, Xi J, Gao L, Hu J. Role of Hepatitis B virus capsid phosphorylation in nucleocapsid disassembly and covalently closed circular DNA formation. PLoS Pathog 2020; 16:e1008459. [PMID: 32226051 PMCID: PMC7145273 DOI: 10.1371/journal.ppat.1008459] [Citation(s) in RCA: 40] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2019] [Revised: 04/09/2020] [Accepted: 03/05/2020] [Indexed: 12/16/2022] Open
Abstract
Hepatitis B virus (HBV) delivers a partially double-stranded, relaxed circular (RC) DNA genome in complete virions to the host cell nucleus for conversion to the covalently closed circular (CCC) DNA, which establishes and sustains viral infection. An overlength pregenomic RNA (pgRNA) is then transcribed from CCC DNA and packaged into immature nucleocapsids (NCs) by the viral core (HBc) protein. pgRNA is reverse transcribed to produce RC DNA in mature NCs, which are then enveloped and secreted as complete virions, or delivered to the nucleus to replenish the nuclear CCC DNA pool. RC DNA, whether originating from extracellular virions or intracellular mature NCs, must be released upon NC disassembly (uncoating) for CCC DNA formation. HBc is known to undergo dynamic phosphorylation and dephosphorylation at its C-terminal domain (CTD) to facilitate pgRNA packaging and reverse transcription. Here, two putative phosphorylation sites in the HBc N-terminal domain (NTD), S44 and S49, were targeted for genetic and biochemical analysis to assess their potential roles in viral replication. The NTD mutant that mimics the non-phosphorylated state (N2A) was competent in all steps of viral replication tested from capsid assembly, pgRNA packaging, reverse transcription, to virion secretion, except for a decrease in CCC DNA formation. On the other hand, the phosphor-mimetic mutant N2E showed a defect in the early step of pgRNA packaging but enhanced the late step of mature NC uncoating and consequently, increased CCC DNA formation. N2E also enhanced phosphorylation in CTD and possibly elsewhere in HBc. Furthermore, inhibition of the cyclin-dependent kinase 2 (CDK2), which is packaged into viral capsids, could block CCC DNA formation. These results prompted us to propose a model whereby rephosphorylation of HBc at both NTD and CTD by the packaged CDK2, following CTD dephosphorylation during NC maturation, facilitates uncoating and CCC DNA formation by destabilizing mature NCs.
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Affiliation(s)
- Jun Luo
- Department of Microbiology and Immunology, The Pennsylvania State University College of Medicine, Hershey, Pennsylvania, United States of America
| | - Ji Xi
- Department of Microbiology and Immunology, The Pennsylvania State University College of Medicine, Hershey, Pennsylvania, United States of America
| | - Lu Gao
- Roche Pharma Research and Early Development, Roche Innovation Center Shanghai, Shanghai, China
| | - Jianming Hu
- Department of Microbiology and Immunology, The Pennsylvania State University College of Medicine, Hershey, Pennsylvania, United States of America
- * E-mail:
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Cytoplasmic Parvovirus Capsids Recruit Importin Beta for Nuclear Delivery. J Virol 2020; 94:JVI.01532-19. [PMID: 31748386 DOI: 10.1128/jvi.01532-19] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2019] [Accepted: 11/16/2019] [Indexed: 02/06/2023] Open
Abstract
Parvoviruses are an important platform for gene and cancer therapy. Their cell entry and the following steps, including nuclear import, are inefficient, limiting their use in therapeutic applications. Two models exist on parvoviral nuclear entry: the classical import of the viral capsid using nuclear transport receptors of the importin (karyopherin) family or the direct attachment of the capsid to the nuclear pore complex leading to the local disintegration of the nuclear envelope. Here, by laser scanning confocal microscopy and in situ proximity ligation analyses combined with coimmunoprecipitation, we show that infection requires importin β-mediated access to the nuclear pore complex and nucleoporin 153-mediated interactions on the nuclear side. The importin β-capsid interaction continued within the nucleoplasm, which suggests a mixed model of nuclear entry in which the classical nuclear import across the nuclear pore complex is accompanied by transient ruptures of the nuclear envelope, also allowing the passive entry of importin β-capsid complexes into the nucleus.IMPORTANCE Parvoviruses are small DNA viruses that deliver their DNA into the postmitotic nuclei, which is an important step for parvoviral gene and cancer therapies. Limitations in virus-receptor interactions or endocytic entry do not fully explain the low transduction/infection efficiency, indicating a bottleneck after virus entry into the cytoplasm. We thus investigated the transfer of parvovirus capsids from the cytoplasm to the nucleus, showing that the nuclear import of the parvovirus capsid follows a unique strategy, which differs from classical nuclear import and those of other viruses.
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Akahori Y, Hijikata M. [Development of hepatitis B virus culture systems]. Uirusu 2020; 70:135-146. [PMID: 34544928 DOI: 10.2222/jsv.70.135] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Recent development of hepatitis B virus (HBV) culture systems has proceeded the molecular virological studies of the life cycle of HBV including infection step. However, the reproduction of HBV life cycle under the more physiological condition may be required to know the nature of HBV more precisely. The HBV culture system, we recently developed using immortalized human hepatocytes cultured in the three dimensional condition, seemed to be one of good tools for that purpose.
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Affiliation(s)
- Yuichi Akahori
- Laboratory of Tumor Viruses, Institute for Frontier Life and Medical Sciences, Kyoto University
| | - Makoto Hijikata
- Laboratory of Tumor Viruses, Institute for Frontier Life and Medical Sciences, Kyoto University
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Abstract
We employ a three-dimensional molecular dynamics to simulate a driven polymer translocation through a nanopore by applying an external force, for four pore diameters and two external forces. To see the polymer and pore interaction effects on translocation time, we studied nine interaction energies. Moreover, to better understand the simulation results, we investigate polymer center of mass, shape factor and the monomer spatial distribution through the translocation process. Our results reveal that increasing the polymer-pore interaction energy is accompanied by an increase in the translocation time and decrease in the process rate. Furthermore, for pores with greater diameter, the translocation becomes faster. The shape analysis of the polymer indicates that the polymer shape is highly sensitive to the interaction energy. In great interactions, the monomers come close to the pore from both sides. As a result, the translocation becomes fast at first and slows down at last. Overall, it can be concluded that the external force does not play a major role in the shape and distribution of translocated monomers. However, the interaction energy between monomer and nanopore has a major effect especially on the distribution of translocated monomers on the trans side.
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Abstract
With a yearly death toll of 880,000, hepatitis B virus (HBV) remains a major health problem worldwide, despite an effective prophylactic vaccine and well-tolerated, effective antivirals. HBV causes chronic hepatitis, fibrosis, cirrhosis, and hepatocellular carcinoma. The viral genome persists in infected hepatocytes even after long-term antiviral therapy, and its integration, though no longer able to support viral replication, destabilizes the host genome. HBV is a DNA virus that utilizes a virus-encoded reverse transcriptase to convert an RNA intermediate, termed pregenomic RNA, into the relaxed circular DNA genome, which is subsequently converted into a covalently closed circular DNA (cccDNA) in the host cell nucleus. cccDNA is maintained in the nucleus of the infected hepatocyte as a stable minichromosome and functions as the viral transcriptional template for the production of all viral gene products, and thus, it is the molecular basis of HBV persistence. The nuclear cccDNA pool can be replenished through recycling of newly synthesized, DNA-containing HBV capsids. Licensed antivirals target the HBV reverse transcriptase activity but fail to eliminate cccDNA, which would be required to cure HBV infection. Elimination of HBV cccDNA is so far only achieved by antiviral immune responses. Thus, this review will focus on possible curative strategies aimed at eliminating or crippling the viral cccDNA. Newer insights into the HBV life cycle and host immune response provide novel, potentially curative therapeutic opportunities and targets.
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Hu J, Cheng J, Tang L, Hu Z, Luo Y, Li Y, Zhou T, Chang J, Guo JT. Virological Basis for the Cure of Chronic Hepatitis B. ACS Infect Dis 2019; 5:659-674. [PMID: 29893548 DOI: 10.1021/acsinfecdis.8b00081] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Hepatitis B virus (HBV) has infected one-third of world population, and 240 million people are chronic carriers, to whom a curative therapy is still not available. Similar to other viruses, persistent HBV infection relies on the virus to exploit host cell functions to support its replication and efficiently evade host innate and adaptive antiviral immunity. Understanding HBV replication and concomitant host cell interactions is thus instrumental for development of therapeutics to disrupt the virus-host interactions critical for its persistence and cure chronic hepatitis B. Although the currently available cell culture systems of HBV infection are refractory to genome-wide high throughput screening of key host cellular factors essential for and/or regulating HBV replication, classic one-gene (or pathway)-at-a-time studies in the last several decades have already revealed many aspects of HBV-host interactions. An overview of the landscape of HBV-hepatocyte interaction indicates that, in addition to more tightly suppressing viral replication by directly targeting viral proteins, disruption of key viral-host cell interactions to eliminate or inactivate the covalently closed circular (ccc) DNA, the most stable HBV replication intermediate that exists as an episomal minichromosome in the nucleus of infected hepatocyte, is essential to achieve a functional cure of chronic hepatitis B. Moreover, therapeutic targeting of integrated HBV DNA and their transcripts may also be required to induce hepatitis B virus surface antigen (HBsAg) seroclearance and prevent liver carcinogenesis.
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Affiliation(s)
- Jin Hu
- Baruch S. Blumberg Institute, 3805 Old Easton Road, Doylestown, Pennsylvania 18902, United States
- Institute of Medicinal Biotechnology, Chinese Academy of Medical Science, 1 Tian-tan Xi-li, Beijing, 100050, China
| | - Junjun Cheng
- Baruch S. Blumberg Institute, 3805 Old Easton Road, Doylestown, Pennsylvania 18902, United States
| | - Liudi Tang
- Microbiology and Immunology Graduate Program, Drexel University College of Medicine, 2900 West Queen Lane, Philadelphia, Pennsylvania 19129, United States
| | - Zhanying Hu
- Baruch S. Blumberg Institute, 3805 Old Easton Road, Doylestown, Pennsylvania 18902, United States
| | - Yue Luo
- Baruch S. Blumberg Institute, 3805 Old Easton Road, Doylestown, Pennsylvania 18902, United States
- Institute of Hepatology, Second Xiangya Hospital, Central South University, 87 Xiangya Road, Changsha, Hunan 410008, China
| | - Yuhuan Li
- Institute of Medicinal Biotechnology, Chinese Academy of Medical Science, 1 Tian-tan Xi-li, Beijing, 100050, China
| | - Tianlun Zhou
- Baruch S. Blumberg Institute, 3805 Old Easton Road, Doylestown, Pennsylvania 18902, United States
| | - Jinhong Chang
- Baruch S. Blumberg Institute, 3805 Old Easton Road, Doylestown, Pennsylvania 18902, United States
| | - Ju-Tao Guo
- Baruch S. Blumberg Institute, 3805 Old Easton Road, Doylestown, Pennsylvania 18902, United States
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Human Hepatitis B Virus Core Protein Inhibits IFNα-Induced IFITM1 Expression by Interacting with BAF200. Viruses 2019; 11:v11050427. [PMID: 31075894 PMCID: PMC6563218 DOI: 10.3390/v11050427] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2019] [Revised: 05/04/2019] [Accepted: 05/07/2019] [Indexed: 02/06/2023] Open
Abstract
Human hepatitis B virus core protein (HBc) is a structural protein of the hepatitis B virus (HBV) and contributes to HBV regulation of host-cell transcription. However, the mechanisms of transcriptional regulation remain poorly characterized. To dissect the function of HBc, a yeast two-hybrid was performed to identify HBc-binding proteins, and the C-terminal of BRG1/hBRM-associated factors 200 (BAF200C) was identified. Then, the existence of HBc interactions with BAF200C and full-length BAF200 was confirmed via co-immunoprecipitation assays in 293T, HepG2 and HepG2-NTCP cells. Furthermore, we show that the binding between HBc and BAF200 was of vital importance to HBc mediated downregulation of interferon-induced transmembrane protein 1 (IFITM1) expression, and the mechanisms for the downregulation were disclosed as follows. Basal level of IFITM1 expression depends on BAF200, rather than the JAK–STAT1 pathway. The interaction of HBc with BAF200 disturbs the stability of the polybromo-associated BAF (PBAF) complex and results in the suppression of IFTM1 transcription. Finally, the antiviral effects of IFITM1 on cell proliferation and HBV replication were found to be partially restored when HBc was co-transfected with BAF200. Collectively, our findings indicate that HBc plays a role in HBV resistance against the antiviral activities of IFNα, providing details about HBV evasion of host innate immunity.
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Heger-Stevic J, Zimmermann P, Lecoq L, Böttcher B, Nassal M. Hepatitis B virus core protein phosphorylation: Identification of the SRPK1 target sites and impact of their occupancy on RNA binding and capsid structure. PLoS Pathog 2018; 14:e1007488. [PMID: 30566530 PMCID: PMC6317823 DOI: 10.1371/journal.ppat.1007488] [Citation(s) in RCA: 57] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2018] [Revised: 01/03/2019] [Accepted: 11/27/2018] [Indexed: 12/19/2022] Open
Abstract
Hepatitis B virus (HBV) replicates its 3 kb DNA genome through capsid-internal reverse transcription, initiated by assembly of 120 core protein (HBc) dimers around a complex of viral pregenomic (pg) RNA and polymerase. Following synthesis of relaxed circular (RC) DNA capsids can be enveloped and secreted as stable virions. Upon infection of a new cell, however, the capsid disintegrates to release the RC-DNA into the nucleus for conversion into covalently closed circular (ccc) DNA. HBc´s interactions with nucleic acids are mediated by an arginine-rich C terminal domain (CTD) with intrinsically strong non-specific RNA binding activity. Adaptation to the changing demands for nucleic acid binding during the viral life cycle is thought to involve dynamic phosphorylation / dephosphorylation events. However, neither the relevant enzymes nor their target sites in HBc are firmly established. Here we developed a bacterial coexpression system enabling access to definably phosphorylated HBc. Combining Phos-tag gel electrophoresis, mass spectrometry and mutagenesis we identified seven of the eight hydroxy amino acids in the CTD as target sites for serine-arginine rich protein kinase 1 (SRPK1); fewer sites were phosphorylated by PKA and PKC. Phosphorylation of all seven sites reduced nonspecific RNA encapsidation as drastically as deletion of the entire CTD and altered CTD surface accessibility, without major structure changes in the capsid shell. The bulk of capsids from human hepatoma cells was similarly highly, yet non-identically, phosphorylated as by SRPK1. While not proving SRPK1 as the infection-relevant HBc kinase the data suggest a mechanism whereby high-level HBc phosphorylation principally suppresses RNA binding whereas one or few strategic dephosphorylation events enable selective packaging of the pgRNA/polymerase complex. The tools developed in this study should greatly facilitate the further deciphering of the role of HBc phosphorylation in HBV infection and its evaluation as a potential new therapeutic target.
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Affiliation(s)
- Julia Heger-Stevic
- University Hospital Freiburg, Department of Medicine II / Molecular Biology, Faculty of Medicine, University of Freiburg, Freiburg, Germany
- Biological Faculty, University of Freiburg, Freiburg, Germany
| | - Peter Zimmermann
- University Hospital Freiburg, Department of Medicine II / Molecular Biology, Faculty of Medicine, University of Freiburg, Freiburg, Germany
- Biological Faculty, University of Freiburg, Freiburg, Germany
| | - Lauriane Lecoq
- Institut de Biologie et Chimie des Protéines, University of Lyon1, Lyon, France
| | - Bettina Böttcher
- Department of Biochemistry, Biocenter, University of Würzburg, Würzburg, Germany
| | - Michael Nassal
- University Hospital Freiburg, Department of Medicine II / Molecular Biology, Faculty of Medicine, University of Freiburg, Freiburg, Germany
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Makjaroen J, Somparn P, Hodge K, Poomipak W, Hirankarn N, Pisitkun T. Comprehensive Proteomics Identification of IFN-λ3-regulated Antiviral Proteins in HBV-transfected Cells. Mol Cell Proteomics 2018; 17:2197-2215. [PMID: 30097535 PMCID: PMC6210224 DOI: 10.1074/mcp.ra118.000735] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2018] [Revised: 06/10/2018] [Indexed: 12/16/2022] Open
Abstract
Interferon lambda (IFN-λ) is a relatively unexplored, yet promising antiviral agent. IFN-λ has recently been tested in clinical trials of chronic hepatitis B virus infection (CHB), with the advantage that side effects may be limited compared with IFN-α, as IFN-λ receptors are found only in epithelial cells. To date, IFN-λ's downstream signaling pathway remains largely unelucidated, particularly via proteomics methods. Here, we report that IFN-λ3 inhibits HBV replication in HepG2.2.15 cells, reducing levels of both HBV transcripts and intracellular HBV DNA. Quantitative proteomic analysis of HBV-transfected cells was performed following 24-hour IFN-λ3 treatment, with parallel IFN-α2a and PBS treatments for comparison using a dimethyl labeling method. The depth of the study allowed us to map the induction of antiviral proteins to multiple points of the viral life cycle, as well as facilitating the identification of antiviral proteins not previously known to be elicited upon HBV infection (e.g. IFITM3, XRN2, and NT5C3A). This study also shows up-regulation of many effectors involved in antigen processing/presentation indicating that this cytokine exerted immunomodulatory effects through several essential molecules for these processes. Interestingly, the 2 subunits of the immunoproteasome cap (PSME1 and PSME2) were up-regulated whereas cap components of the constitutive proteasome were down-regulated upon both IFN treatments, suggesting coordinated modulation toward the antigen processing/presentation mode. Furthermore, in addition to confirming canonical activation of interferon-stimulated gene (ISG) transcription through the JAK-STAT pathway, we reveal that IFN-λ3 restored levels of RIG-I and RIG-G, proteins known to be suppressed by HBV. Enrichment analysis demonstrated that several biological processes including RNA metabolism, translation, and ER-targeting were differentially regulated upon treatment with IFN-λ3 versus IFN-α2a. Our proteomic data suggests that IFN-λ3 regulates an array of cellular processes to control HBV replication.
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Affiliation(s)
- Jiradej Makjaroen
- From the ‡Medical Microbiology Interdisciplinary Program, Graduate School, Chulalongkorn University, Bangkok, Thailand
- §Center of Excellence in Immunology and Immune-mediated Diseases, Department of Microbiology, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand
- ¶Center of Excellence in Systems Biology, Research Affairs, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand
| | - Poorichaya Somparn
- §Center of Excellence in Immunology and Immune-mediated Diseases, Department of Microbiology, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand
- ¶Center of Excellence in Systems Biology, Research Affairs, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand
| | - Kenneth Hodge
- ¶Center of Excellence in Systems Biology, Research Affairs, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand
| | - Witthaya Poomipak
- ¶Center of Excellence in Systems Biology, Research Affairs, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand
| | - Nattiya Hirankarn
- §Center of Excellence in Immunology and Immune-mediated Diseases, Department of Microbiology, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand
| | - Trairak Pisitkun
- ¶Center of Excellence in Systems Biology, Research Affairs, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand
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Chabrolles H, Lahlali T, Auclair H, Salvetti A. [The multiple functions of the hepatitis B virus core protein: new research directions and therapeutic challenges]. Med Sci (Paris) 2018; 34:693-700. [PMID: 30230454 DOI: 10.1051/medsci/20183408016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Chronic infection by hepatitis B virus (HBV) is a major public health problem with more than 250 millions of people chronically infected worldwide who have a high risk to develop cirrhosis and hepatocellular carcinoma. Available treatments reduce viremia but do not eradicate the virus from hepatocytes. Therefore, there is an urgent need to develop new classes of antiviral molecules and the viral capsid protein, Core, constitutes a new favored target. Core protein Allosteric Modulators (CAMs) targeting its assembly functions are in clinical development. In addition, investigation of Core regulatory functions may lead to the development of compounds targeting cellular factors (HTA) that could be used in combined therapies aiming to achieve a better control of HBV replication.
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Affiliation(s)
- Hélène Chabrolles
- Centre de recherche en cancérologie de Lyon (CRCL), Inserm U1052, 151, cours Albert Thomas, 69003 Lyon, France
| | - Thomas Lahlali
- Centre de recherche en cancérologie de Lyon (CRCL), Inserm U1052, 151, cours Albert Thomas, 69003 Lyon, France
| | - Héloïse Auclair
- Centre de recherche en cancérologie de Lyon (CRCL), Inserm U1052, 151, cours Albert Thomas, 69003 Lyon, France
| | - Anna Salvetti
- Centre de recherche en cancérologie de Lyon (CRCL), Inserm U1052, 151, cours Albert Thomas, 69003 Lyon, France
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Hadden JA, Perilla JR, Schlicksup CJ, Venkatakrishnan B, Zlotnick A, Schulten K. All-atom molecular dynamics of the HBV capsid reveals insights into biological function and cryo-EM resolution limits. eLife 2018; 7:32478. [PMID: 29708495 PMCID: PMC5927769 DOI: 10.7554/elife.32478] [Citation(s) in RCA: 63] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2017] [Accepted: 04/05/2018] [Indexed: 12/11/2022] Open
Abstract
The hepatitis B virus capsid represents a promising therapeutic target. Experiments suggest the capsid must be flexible to function; however, capsid structure and dynamics have not been thoroughly characterized in the absence of icosahedral symmetry constraints. Here, all-atom molecular dynamics simulations are leveraged to investigate the capsid without symmetry bias, enabling study of capsid flexibility and its implications for biological function and cryo-EM resolution limits. Simulation results confirm flexibility and reveal a propensity for asymmetric distortion. The capsid’s influence on ionic species suggests a mechanism for modulating the display of cellular signals and implicates the capsid’s triangular pores as the location of signal exposure. A theoretical image reconstruction performed using simulated conformations indicates how capsid flexibility may limit the resolution of cryo-EM. Overall, the present work provides functional insight beyond what is accessible to experimental methods and raises important considerations regarding asymmetry in structural studies of icosahedral virus capsids.
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Affiliation(s)
- Jodi A Hadden
- Department of Chemistry and Biochemistry, University of Delaware, Newark, United States
| | - Juan R Perilla
- Department of Chemistry and Biochemistry, University of Delaware, Newark, United States
| | | | | | - Adam Zlotnick
- Department of Molecular and Cellular Biochemistry, Indiana University, Bloomington, United States
| | - Klaus Schulten
- Department of Physics, University of Illinois at Urbana-Champaign, Urbana, United States.,Beckman Institute, University of Illinois at Urbana-Champaign, Urbana, United States
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Osseman Q, Gallucci L, Au S, Cazenave C, Berdance E, Blondot ML, Cassany A, Bégu D, Ragues J, Aknin C, Sominskaya I, Dishlers A, Rabe B, Anderson F, Panté N, Kann M. The chaperone dynein LL1 mediates cytoplasmic transport of empty and mature hepatitis B virus capsids. J Hepatol 2018; 68:441-448. [PMID: 29113909 DOI: 10.1016/j.jhep.2017.10.032] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/22/2017] [Revised: 09/26/2017] [Accepted: 10/27/2017] [Indexed: 02/08/2023]
Abstract
BACKGROUND & AIMS Hepatitis B virus (HBV) has a DNA genome but replicates within the nucleus by reverse transcription of an RNA pregenome, which is converted to DNA in cytoplasmic capsids. Capsids in this compartment are correlated with inflammation and epitopes of the capsid protein core (Cp) are a major target for T cell-mediated immune responses. We investigated the mechanism of cytoplasmic capsid transport, which is important for infection but also for cytosolic capsid removal. METHODS We used virion-derived capsids containing mature rcDNA (matC) and empty capsids (empC). RNA-containing capsids (rnaC) were used as a control. The investigations comprised pull-down assays for identification of cellular interaction partners, immune fluorescence microscopy for their colocalization and electron microscopy after microinjection to determine their biological significance. RESULTS matC and empC underwent active transport through the cytoplasm towards the nucleus, while rnaC was poorly transported. We identified the dynein light chain LL1 as a functional interaction partner linking capsids to the dynein motor complex and showed that there is no compensatory transport pathway. Using capsid and dynein LL1 mutants we characterized the required domains on the capsid and LL1. CONCLUSIONS This is the first investigation on the detailed molecular mechanism of how matC pass the cytoplasm upon infection and how empC can be actively removed from the cytoplasm into the nucleus. Considering that hepatocytes with cytoplasmic capsids are better recognized by the T cells, we hypothesize that targeting capsid DynLL1-interaction will not only block HBV infection but also stimulate elimination of infected cells. LAY SUMMARY In this study, we identified the molecular details of HBV translocation through the cytoplasm. Our evidence offers a new drug target which could not only inhibit infection but also stimulate immune clearance of HBV infected cells.
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Affiliation(s)
- Quentin Osseman
- Univ. de Bordeaux, Microbiologie Fondamentale et Pathogénicité, UMR 5234, 33076 Bordeaux, France; CNRS, Microbiologie Fondamentale et Pathogénicité, UMR 5234, Bordeaux, France
| | - Lara Gallucci
- Univ. de Bordeaux, Microbiologie Fondamentale et Pathogénicité, UMR 5234, 33076 Bordeaux, France; CNRS, Microbiologie Fondamentale et Pathogénicité, UMR 5234, Bordeaux, France
| | - Shelly Au
- Department of Zoology, University of British Columbia Vancouver, B.C. V6T 1Z4, Canada
| | - Christian Cazenave
- Univ. de Bordeaux, Microbiologie Fondamentale et Pathogénicité, UMR 5234, 33076 Bordeaux, France; CNRS, Microbiologie Fondamentale et Pathogénicité, UMR 5234, Bordeaux, France
| | - Elodie Berdance
- Univ. de Bordeaux, Microbiologie Fondamentale et Pathogénicité, UMR 5234, 33076 Bordeaux, France; CNRS, Microbiologie Fondamentale et Pathogénicité, UMR 5234, Bordeaux, France
| | - Marie-Lise Blondot
- Univ. de Bordeaux, Microbiologie Fondamentale et Pathogénicité, UMR 5234, 33076 Bordeaux, France; CNRS, Microbiologie Fondamentale et Pathogénicité, UMR 5234, Bordeaux, France
| | - Aurélia Cassany
- Univ. de Bordeaux, Microbiologie Fondamentale et Pathogénicité, UMR 5234, 33076 Bordeaux, France; CNRS, Microbiologie Fondamentale et Pathogénicité, UMR 5234, Bordeaux, France
| | - Dominique Bégu
- Univ. de Bordeaux, Microbiologie Fondamentale et Pathogénicité, UMR 5234, 33076 Bordeaux, France; CNRS, Microbiologie Fondamentale et Pathogénicité, UMR 5234, Bordeaux, France
| | - Jessica Ragues
- Univ. de Bordeaux, Microbiologie Fondamentale et Pathogénicité, UMR 5234, 33076 Bordeaux, France; CNRS, Microbiologie Fondamentale et Pathogénicité, UMR 5234, Bordeaux, France
| | - Cindy Aknin
- Univ. de Bordeaux, Microbiologie Fondamentale et Pathogénicité, UMR 5234, 33076 Bordeaux, France; CNRS, Microbiologie Fondamentale et Pathogénicité, UMR 5234, Bordeaux, France
| | | | - Andris Dishlers
- Latvian Biomedical Research and Study Center, 1067 Riga, Latvia
| | - Birgit Rabe
- Institute of Medical Virology, University of Giessen, 35392 Giessen, Germany
| | - Fenja Anderson
- Institute of Medical Virology, University of Giessen, 35392 Giessen, Germany; Institute of Virology, Hannover Medical School, 30625 Hannover, Germany
| | - Nelly Panté
- Department of Zoology, University of British Columbia Vancouver, B.C. V6T 1Z4, Canada
| | - Michael Kann
- Univ. de Bordeaux, Microbiologie Fondamentale et Pathogénicité, UMR 5234, 33076 Bordeaux, France; CNRS, Microbiologie Fondamentale et Pathogénicité, UMR 5234, Bordeaux, France; Institute of Medical Virology, University of Giessen, 35392 Giessen, Germany; CHU de Bordeaux, 33000 Bordeaux, France.
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PRMT5: A novel regulator of Hepatitis B virus replication and an arginine methylase of HBV core. PLoS One 2017; 12:e0186982. [PMID: 29065155 PMCID: PMC5655436 DOI: 10.1371/journal.pone.0186982] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2017] [Accepted: 10/11/2017] [Indexed: 02/08/2023] Open
Abstract
In mammals, protein arginine methyltransferase 5, PRMT5, is the main type II enzyme responsible for the majority of symmetric dimethylarginine formation in polypeptides. Recent study reported that PRMT5 restricts Hepatitis B virus (HBV) replication through epigenetic repression of HBV DNA transcription and interference with encapsidation of pregenomic RNA. Here we demonstrate that PRMT5 interacts with the HBV core (HBc) protein and dimethylates arginine residues within the arginine-rich domain (ARD) of the carboxyl-terminus. ARD consists of four arginine rich subdomains, ARDI, ARDII, ARDIII and ARDIV. Mutation analysis of ARDs revealed that arginine methylation of HBc required the wild-type status of both ARDI and ARDII. Mass spectrometry analysis of HBc identified multiple potential ubiquitination, methylation and phosphorylation sites, out of which lysine K7 and arginines R150 (within ARDI) and R156 (outside ARDs) were shown to be modified by ubiquitination and methylation, respectively. The HBc symmetric dimethylation appeared to be linked to serine phosphorylation and nuclear import of HBc protein. Conversely, the monomethylated HBc retained in the cytoplasm. Thus, overexpression of PRMT5 led to increased nuclear accumulation of HBc, and vice versa, down-regulation of PRMT5 resulted in reduced levels of HBc in nuclei of transfected cells. In summary, we identified PRMT5 as a potent controller of HBc cell trafficking and function and described two novel types of HBc post-translational modifications (PTMs), arginine methylation and ubiquitination.
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Activation of Stimulator of Interferon Genes in Hepatocytes Suppresses the Replication of Hepatitis B Virus. Antimicrob Agents Chemother 2017; 61:AAC.00771-17. [PMID: 28717041 DOI: 10.1128/aac.00771-17] [Citation(s) in RCA: 47] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2017] [Accepted: 07/11/2017] [Indexed: 12/12/2022] Open
Abstract
Induction of interferon and proinflammatory cytokines is a hallmark of the infection of many different viruses. However, hepatitis B virus (HBV) does not elicit a detectable cytokine response in infected hepatocytes. In order to investigate the molecular mechanism underlying the innate immune evasion, a functional cyclic GMP-AMP (cGAMP) synthase (cGAS)-stimulator of interferon genes (STING) pathway was reconstituted in a human hepatoma cell line supporting tetracycline-inducible HBV replication. It was demonstrated that induction of HBV replication neither activated nor inhibited this cytosolic DNA sensing pathway. However, human hepatoma cells, as well as immortalized mouse hepatocytes, express low levels of STING, which upon activation by cGAMP, the natural ligand of STING, led to induction of a proinflammatory cytokine response. Treatment of immortalized mouse hepatocytes supporting HBV replication with either cGAMP or a small molecule pharmacologic STING agonist significantly reduced viral DNA in a STING- and Janus kinase 1-dependent manner. Moreover, cGAMP treatment was able to induce inflammatory cytokine gene expression and inhibit the transcription of covalently closed circular DNA in HBV-infected human hepatoma cells expressing sodium taurocholate cotransporting polypeptide, an essential receptor for HBV infection of hepatocytes. The studies reported here and previously (F. Guo et al., Antimicrob Agents Chemother 59:1273-1281, 2015, https://doi.org/10.1128/AAC.04321-14) thus support the notion that pharmacological activation of STING in macrophages and hepatocytes induces host innate responses that can efficiently control HBV replication. Hence, despite not playing a significant role in host innate immune response to HBV infection of hepatocytes, STING is potentially a valuable target for immunotherapy of chronic hepatitis B.
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Schreiner S, Nassal M. A Role for the Host DNA Damage Response in Hepatitis B Virus cccDNA Formation-and Beyond? Viruses 2017; 9:v9050125. [PMID: 28531167 PMCID: PMC5454437 DOI: 10.3390/v9050125] [Citation(s) in RCA: 69] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2017] [Revised: 05/16/2017] [Accepted: 05/18/2017] [Indexed: 12/12/2022] Open
Abstract
Chronic hepatitis B virus (HBV) infection puts more than 250 million people at a greatly increased risk to develop end-stage liver disease. Like all hepadnaviruses, HBV replicates via protein-primed reverse transcription of a pregenomic (pg) RNA, yielding an unusually structured, viral polymerase-linked relaxed-circular (RC) DNA as genome in infectious particles. Upon infection, RC-DNA is converted into nuclear covalently closed circular (ccc) DNA. Associating with cellular proteins into an episomal minichromosome, cccDNA acts as template for new viral RNAs, ensuring formation of progeny virions. Hence, cccDNA represents the viral persistence reservoir that is not directly targeted by current anti-HBV therapeutics. Eliminating cccDNA will thus be at the heart of a cure for chronic hepatitis B. The low production of HBV cccDNA in most experimental models and the associated problems in reliable cccDNA quantitation have long hampered a deeper understanding of cccDNA molecular biology. Recent advancements including cccDNA-dependent cell culture systems have begun to identify select host DNA repair enzymes that HBV usurps for RC-DNA to cccDNA conversion. While this list is bound to grow, it may represent just one facet of a broader interaction with the cellular DNA damage response (DDR), a network of pathways that sense and repair aberrant DNA structures and in the process profoundly affect the cell cycle, up to inducing cell death if repair fails. Given the divergent interactions between other viruses and the DDR it will be intriguing to see how HBV copes with this multipronged host system.
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Affiliation(s)
- Sabrina Schreiner
- Institute of Virology, Technische Universität München/Helmholtz Zentrum München, Ingolstädter Landstr. 1, Neuherberg, D-85764 Munich, Germany.
| | - Michael Nassal
- Dept. of Internal Medicine II/Molecular Biology, University Hospital Freiburg, Hugstetter Str. 55, D-79106 Freiburg, Germany.
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