1
|
Inoue T, Yagi S, Tanaka Y. Two Concepts of Hepatitis B Core-Related Antigen Assay: A Highly Sensitive and Rapid Assay or an Effective Tool for Widespread Screening. Viruses 2024; 16:848. [PMID: 38932141 PMCID: PMC11209401 DOI: 10.3390/v16060848] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2024] [Revised: 05/20/2024] [Accepted: 05/24/2024] [Indexed: 06/28/2024] Open
Abstract
Hepatitis B core-related antigen (HBcrAg) reflects the activity of intrahepatic covalently closed circular DNA. HBcrAg can be detected even in chronic hepatitis B patients in whom serum HBV DNA or hepatitis B surface antigen is undetectable. The HBcrAg measurement system was developed based on two concepts. One is a fully-automated and highly-sensitive HBcrAg assay (iTACT-HBcrAg) and the other is a point-of-care testing (POCT) that can be used in in resource-limited areas. iTACT-HBcrAg is an alternative to HBV DNA for monitoring HBV reactivation and predicting the development of hepatocellular carcinoma. This validated biomarker is available in routine clinical practice in Japan. Currently, international guidelines for the prevention of mother-to-child transmission recommend anti-HBV prophylaxis for pregnant women with high viral loads. However, over 95% of HBV-infected individuals live in countries where HBV DNA quantification is widely unavailable. Given this situation, a rapid and simple HBcrAg assay for POCT would be highly effective. Long-term anti-HBV therapy may have potential side effects and appropriate treatment should be provided to eligible patients. Therefore, a simple method of determining the indication for anti-HBV treatment would be ideal. This review provides up-to-date information regarding the clinical value of HBcrAg in HBV management, based on iTACT-HBcrAg or POCT.
Collapse
Affiliation(s)
- Takako Inoue
- Department of Clinical Laboratory Medicine, Nagoya City University Hospital, Nagoya 467-8602, Japan;
| | - Shintaro Yagi
- Research and Development Department, Advanced Life Science Institute, Inc., Hachioji 192-0031, Japan;
| | - Yasuhito Tanaka
- Department of Gastroenterology and Hepatology, Faculty of Life Sciences, Kumamoto University, Kumamoto 860-8556, Japan
| |
Collapse
|
2
|
Yang R, Ko YH, Li F, Lokareddy RK, Hou CFD, Kim C, Klein S, Antolínez S, Marín JF, Pérez-Segura C, Jarrold MF, Zlotnick A, Hadden-Perilla JA, Cingolani G. Structural basis for nuclear import of hepatitis B virus (HBV) nucleocapsid core. SCIENCE ADVANCES 2024; 10:eadi7606. [PMID: 38198557 PMCID: PMC10780889 DOI: 10.1126/sciadv.adi7606] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/17/2023] [Accepted: 12/08/2023] [Indexed: 01/12/2024]
Abstract
Nuclear import of the hepatitis B virus (HBV) nucleocapsid is essential for replication that occurs in the nucleus. The ~360-angstrom HBV capsid translocates to the nuclear pore complex (NPC) as an intact particle, hijacking human importins in a reaction stimulated by host kinases. This paper describes the mechanisms of HBV capsid recognition by importins. We found that importin α1 binds a nuclear localization signal (NLS) at the far end of the HBV coat protein Cp183 carboxyl-terminal domain (CTD). This NLS is exposed to the capsid surface through a pore at the icosahedral quasi-sixfold vertex. Phosphorylation at serine-155, serine-162, and serine-170 promotes CTD compaction but does not affect the affinity for importin α1. The binding of 30 importin α1/β1 augments HBV capsid diameter to ~620 angstroms, close to the maximum size trafficable through the NPC. We propose that phosphorylation favors CTD externalization and prompts its compaction at the capsid surface, exposing the NLS to importins.
Collapse
Affiliation(s)
- Ruoyu Yang
- Department of Biochemistry and Molecular Biology, Thomas Jefferson University, 1020 Locust Street, Philadelphia, PA 19107, USA
| | - Ying-Hui Ko
- Department of Biochemistry and Molecular Genetics, The University of Alabama at Birmingham, 1825 University Blvd, Birmingham, AL 35294, USA
| | - Fenglin Li
- Department of Biochemistry and Molecular Biology, Thomas Jefferson University, 1020 Locust Street, Philadelphia, PA 19107, USA
| | - Ravi K. Lokareddy
- Department of Biochemistry and Molecular Genetics, The University of Alabama at Birmingham, 1825 University Blvd, Birmingham, AL 35294, USA
| | - Chun-Feng David Hou
- Department of Biochemistry and Molecular Biology, Thomas Jefferson University, 1020 Locust Street, Philadelphia, PA 19107, USA
| | - Christine Kim
- Department of Molecular and Cellular Biochemistry, Indiana University, Bloomington, Indiana, IN 47405, USA
| | - Shelby Klein
- Department of Chemistry, Indiana University, Bloomington, Indiana, IN 47405, USA
| | - Santiago Antolínez
- Department of Chemistry and Biochemistry, University of Delaware, Newark, DE 19716, USA
| | - Juan F. Marín
- Department of Chemistry and Biochemistry, University of Delaware, Newark, DE 19716, USA
| | - Carolina Pérez-Segura
- Department of Chemistry and Biochemistry, University of Delaware, Newark, DE 19716, USA
| | - Martin F. Jarrold
- Department of Chemistry, Indiana University, Bloomington, Indiana, IN 47405, USA
| | - Adam Zlotnick
- Department of Molecular and Cellular Biochemistry, Indiana University, Bloomington, Indiana, IN 47405, USA
| | | | - Gino Cingolani
- Department of Biochemistry and Molecular Genetics, The University of Alabama at Birmingham, 1825 University Blvd, Birmingham, AL 35294, USA
| |
Collapse
|
3
|
Nayak S, Gowda J, Abbas SA, Kim H, Han SB. Recent Advances in the Development of Sulfamoyl-Based Hepatitis B Virus Nucleocapsid Assembly Modulators. Viruses 2023; 15:2367. [PMID: 38140607 PMCID: PMC10747759 DOI: 10.3390/v15122367] [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: 10/15/2023] [Revised: 11/24/2023] [Accepted: 11/27/2023] [Indexed: 12/24/2023] Open
Abstract
Hepatitis B virus (HBV) is the primary contributor to severe liver ailments, encompassing conditions such as cirrhosis and hepatocellular carcinoma. Globally, 257 million people are affected by HBV annually and 887,000 deaths are attributed to it, representing a substantial health burden. Regrettably, none of the existing therapies for chronic hepatitis B (CHB) have achieved satisfactory clinical cure rates. This issue stems from the existence of covalently closed circular DNA (cccDNA), which is difficult to eliminate from the nucleus of infected hepatocytes. HBV genetic material is composed of partially double-stranded DNA that forms complexes with viral polymerase inside an icosahedral capsid composed of a dimeric core protein. The HBV core protein, consisting of 183 to 185 amino acids, plays integral roles in multiple essential functions within the HBV replication process. In this review, we describe the effects of sulfamoyl-based carboxamide capsid assembly modulators (CAMs) on capsid assembly, which can suppress HBV replication and disrupt the production of new cccDNA. We present research on classical, first-generation sulfamoyl benzocarboxamide CAMs, elucidating their structural composition and antiviral efficacy. Additionally, we explore newly identified sulfamoyl-based CAMs, including sulfamoyl bicyclic carboxamides, sulfamoyl aromatic heterocyclic carboxamides, sulfamoyl aliphatic heterocyclic carboxamides, cyclic sulfonamides, and non-carboxamide sulfomoyl-based CAMs. We believe that certain molecules derived from sulfamoyl groups have the potential to be developed into essential components of a well-suited combination therapy, ultimately yielding superior clinical efficacy outcomes in the future.
Collapse
Affiliation(s)
- Sandesha Nayak
- Therapeutics and Biotechnology Division, Korea Research Institute of Chemical Technology, Daejeon 34114, Republic of Korea
- Department of Medicinal Chemistry and Pharmacology, University of Science & Technology, Daejeon 34113, Republic of Korea
| | - Jayaraj Gowda
- Therapeutics and Biotechnology Division, Korea Research Institute of Chemical Technology, Daejeon 34114, Republic of Korea
- Department of Medicinal Chemistry and Pharmacology, University of Science & Technology, Daejeon 34113, Republic of Korea
| | - Syed Azeem Abbas
- Therapeutics and Biotechnology Division, Korea Research Institute of Chemical Technology, Daejeon 34114, Republic of Korea
- Department of Medicinal Chemistry and Pharmacology, University of Science & Technology, Daejeon 34113, Republic of Korea
| | - Hyejin Kim
- Therapeutics and Biotechnology Division, Korea Research Institute of Chemical Technology, Daejeon 34114, Republic of Korea
| | - Soo Bong Han
- Therapeutics and Biotechnology Division, Korea Research Institute of Chemical Technology, Daejeon 34114, Republic of Korea
- Department of Medicinal Chemistry and Pharmacology, University of Science & Technology, Daejeon 34113, Republic of Korea
| |
Collapse
|
4
|
Geissler R, Patel M, Anderson M, Vaillant A, Qiu X, Cloherty G. Novel fully automated prototype assays for specific detection of phosphorylated and non-phosphorylated Hepatitis B core antigens. J Clin Virol 2023; 166:105529. [PMID: 37406597 DOI: 10.1016/j.jcv.2023.105529] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2023] [Revised: 06/23/2023] [Accepted: 06/28/2023] [Indexed: 07/07/2023]
Abstract
BACKGROUND Hepatitis B core antigen (HBcAg) has been proposed as a surrogate marker to reflect transcriptional activity of HBV covalently closed circular DNA (cccDNA) during active infections and may be a valuable tool to monitor the efficacy of antiviral therapies. However, HBcAg-specific immunoassays are unavailable, and current assays that measure hepatitis B core-related antigen (HBcrAg) cannot distinguish between HBcAg, HBeAg, and precore (PreC) proteins. OBJECTIVE Two fully automated assays were developed to specifically detect phosphorylated HBcAg (P-HBcAg, representing non-HBV DNA-containing particles) and non-phosphorylated HBcAg (representing HBV DNA-containing particles) circulating in HBV infected patients. STUDY DESIGN P-HBcAg and HBcAg levels were analyzed in 124 single timepoint patients with active infections, in three longitudinal specimens from patients with acute HBV infections, and in four chronic hepatitis B (CHB) patients on-therapy (TDF - tenofovir disoproxil fumarate, pegIFN - pegylated interferon, NAPs - nucleic acids polymers). RESULTS Analyzing acute infections revealed that P-HBcAg and HBcAg levels correlate more closely than HBcrAg to HBV DNA. During antiviral treatment of CHB patients, HBcAg correlates well with HBV DNA and indicates a therapeutic response to the treatment at the beginning of the therapy. In contrast, P-HBcAg tracks more closely to HBV RNA. Importantly, P-HBcAg is detectable several months after HBcAg became undetectable indicating that cccDNA is still transcriptionally active in hepatocytes. CONCLUSIONS Overall, the ability to specifically distinguish between the various states of HBcAg (phosphorylated and non-phosphorylated) can provide additional insights for disease staging, drug development, and management of HBV therapies.
Collapse
Affiliation(s)
- Rene Geissler
- Abbott Laboratories, Abbott Diagnostics Division, Abbott Park, Illinois, United States.
| | - Megha Patel
- Abbott Laboratories, Abbott Diagnostics Division, Abbott Park, Illinois, United States
| | - Mark Anderson
- Abbott Laboratories, Abbott Diagnostics Division, Abbott Park, Illinois, United States
| | | | - Xiaoxing Qiu
- Abbott Laboratories, Abbott Diagnostics Division, Abbott Park, Illinois, United States
| | - Gavin Cloherty
- Abbott Laboratories, Abbott Diagnostics Division, Abbott Park, Illinois, United States
| |
Collapse
|
5
|
McFadden WM, Sarafianos SG. Biology of the hepatitis B virus (HBV) core and capsid assembly modulators (CAMs) for chronic hepatitis B (CHB) cure. Glob Health Med 2023; 5:199-207. [PMID: 37655181 PMCID: PMC10461335 DOI: 10.35772/ghm.2023.01065] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2023] [Revised: 06/03/2023] [Accepted: 06/30/2023] [Indexed: 09/02/2023]
Abstract
Hepatitis B virus (HBV) is a hepadnavirus, a small DNA virus that infects liver tissue, with some unusual replication steps that share similarities to retroviruses. HBV infection can lead to chronic hepatitis B (CHB), a life-long infection associated with significant risks of liver disease, especially if untreated. HBV is a significant global health problem, with hundreds of millions currently living with CHB. Currently approved strategies to prevent or inhibit HBV are highly effective, however, a cure for CHB has remained elusive. To achieve a cure, elimination of the functionally integrated HBV covalently closed chromosomal DNA (cccDNA) genome is required. The capsid core is an essential component of HBV replication, serving roles when establishing infection and in creating new virions. Over the last two and a half decades, significant efforts have been made to find and characterize antivirals that target the capsid, specifically the HBV core protein (Cp). The antivirals that interfere with the kinetics and morphology of the capsid, termed capsid assembly modulators (CAMs), are extremely potent, and clinical investigations indicate they are well tolerated and highly effective. Several CAMs offer the potential to cure CHB by decreasing the cccDNA pools. Here, we review the biology of the HBV capsid, focused on Cp, and the development of inhibitors that target it.
Collapse
Affiliation(s)
- William M. McFadden
- Center for ViroScience and Cure, Laboratory of Biochemical Pharmacology, Department of Pediatrics, Emory University School of Medicine, Atlanta, GA, USA
- Children's Healthcare of Atlanta, Atlanta, GA, USA
| | - Stefan G. Sarafianos
- Center for ViroScience and Cure, Laboratory of Biochemical Pharmacology, Department of Pediatrics, Emory University School of Medicine, Atlanta, GA, USA
- Children's Healthcare of Atlanta, Atlanta, GA, USA
| |
Collapse
|
6
|
Hofmann S, Plank V, Groitl P, Skvorc N, Hofmann K, Luther J, Ko C, Zimmerman P, Bruss V, Stadler D, Carpentier A, Rezk S, Nassal M, Protzer U, Schreiner S. SUMO Modification of Hepatitis B Virus Core Mediates Nuclear Entry, Promyelocytic Leukemia Nuclear Body Association, and Efficient Formation of Covalently Closed Circular DNA. Microbiol Spectr 2023; 11:e0044623. [PMID: 37199632 PMCID: PMC10269885 DOI: 10.1128/spectrum.00446-23] [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: 02/05/2023] [Accepted: 04/24/2023] [Indexed: 05/19/2023] Open
Abstract
Persistence of hepatitis B virus (HBV) infection is due to a nuclear covalently closed circular DNA (cccDNA), generated from the virion-borne relaxed circular DNA (rcDNA) genome in a process likely involving numerous cell factors from the host DNA damage response (DDR). The HBV core protein mediates rcDNA transport to the nucleus and likely affects stability and transcriptional activity of cccDNA. Our study aimed at investigating the role of HBV core protein and its posttranslational modification (PTM) with SUMO (small ubiquitin-like modifiers) during the establishment of cccDNA. HBV core protein SUMO PTM was analyzed in His-SUMO-overexpressing cell lines. The impact of HBV core SUMOylation on association with cellular interaction partners and on the HBV life cycle was determined using SUMOylation-deficient mutants of the HBV core protein. Here, we show that the HBV core protein is posttranslationally modified by the addition of SUMO and that this modification impacts nuclear import of rcDNA. By using SUMOylation-deficient HBV core mutants, we show that SUMO modification is a prerequisite for the association with specific promyelocytic leukemia nuclear bodies (PML-NBs) and regulates the conversion of rcDNA to cccDNA. By in vitro SUMOylation of HBV core, we obtained evidence that SUMOylation triggers nucleocapsid disassembly, providing novel insights into the nuclear import process of rcDNA. HBV core protein SUMOylation and subsequent association with PML bodies in the nucleus constitute a key step in the conversion of HBV rcDNA to cccDNA and therefore a promising target for inhibiting formation of the HBV persistence reservoir. IMPORTANCE HBV cccDNA is formed from the incomplete rcDNA involving several host DDR proteins. The exact process and the site of cccDNA formation are poorly understood. Here, we show that HBV core protein SUMO modification is a novel PTM regulating the function of HBV core. A minor specific fraction of the HBV core protein resides with PML-NBs in the nuclear matrix. SUMO modification of HBV core protein mediates its recruitment to specific PML-NBs within the host cell. Within HBV nucleocapsids, SUMOylation of HBV core induces HBV capsid disassembly and is a prerequisite for nuclear entry of HBV core. SUMO HBV core protein association with PML-NBs is crucial for efficient conversion of rcDNA to cccDNA and for the establishment of the viral persistence reservoir. HBV core protein SUMO modification and the subsequent association with PML-NBs might constitute a potential novel target in the development of drugs targeting the cccDNA.
Collapse
Affiliation(s)
- Samuel Hofmann
- Institute of Virology, School of Medicine, Technical University of Munich, Germany
- Institute of Virology, Hannover Medical School, Hannover, Germany
| | - Verena Plank
- Institute of Virology, School of Medicine, Technical University of Munich, Germany
| | - Peter Groitl
- Institute of Virology, School of Medicine, Technical University of Munich, Germany
| | - Nathalie Skvorc
- Institute of Virology, School of Medicine, Technical University of Munich, Germany
| | - Katharina Hofmann
- Institute of Virology, School of Medicine, Technical University of Munich, Germany
- Institute of Virology, Hannover Medical School, Hannover, Germany
| | - Julius Luther
- Institute of Virology, Hannover Medical School, Hannover, Germany
| | - Chunkyu Ko
- Institute of Virology, School of Medicine, Technical University of Munich, Germany
- Institute of Virology, Helmholtz Zentrum München, Munich, Germany
| | - Peter Zimmerman
- Department of Internal Medicine II/Molecular Biology, University Hospital Freiburg, Freiburg, Germany
| | - Volker Bruss
- Institute of Virology, Helmholtz Zentrum München, Munich, Germany
| | - Daniela Stadler
- Institute of Virology, School of Medicine, Technical University of Munich, Germany
- Institute of Virology, Helmholtz Zentrum München, Munich, Germany
| | | | - Shahinda Rezk
- Institute of Virology, School of Medicine, Technical University of Munich, Germany
- Medical Research Institute, Department of Molecular and Diagnostic Microbiology, Alexandria University, Alexandria, Egypt
| | - Michael Nassal
- Department of Internal Medicine II/Molecular Biology, University Hospital Freiburg, Freiburg, Germany
| | - Ulrike Protzer
- Institute of Virology, School of Medicine, Technical University of Munich, Germany
- Institute of Virology, Helmholtz Zentrum München, Munich, Germany
- German Center for Infection Research, Munich, Germany
| | - Sabrina Schreiner
- Institute of Virology, School of Medicine, Technical University of Munich, Germany
- Institute of Virology, Hannover Medical School, Hannover, Germany
- Institute of Virology, Helmholtz Zentrum München, Munich, Germany
- German Center for Infection Research, Munich, Germany
- Cluster of Excellence RESIST (Resolving Infection Susceptibility; EXC 2155), Hannover Medical School, Hannover, Germany
| |
Collapse
|
7
|
Mohebbi A, Ghorbanzadeh T, Naderifar S, Khalaj F, Askari FS, Sammak AS. A fragment-based drug discovery developed on ciclopirox for inhibition of Hepatitis B virus core protein: An in silico study. PLoS One 2023; 18:e0285941. [PMID: 37196004 DOI: 10.1371/journal.pone.0285941] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2022] [Accepted: 05/05/2023] [Indexed: 05/19/2023] Open
Abstract
The Hepatitis B virus (HBV) core protein is an attractive target for preventing capsid assembly and viral replication. Drug repurposing strategies have introduced several drugs targeting HBV core protein. This study used a fragment-based drug discovery (FBDD) approach to reconstruct a repurposed core protein inhibitor to some novel antiviral derivatives. Auto Core Fragment in silico Screening (ACFIS) server was used for deconstruction-reconstruction of Ciclopirox in complex with HBV core protein. The Ciclopirox derivatives were ranked based on their free energy of binding (ΔGB). A quantitative structure affinity relationship (QSAR) was established on the Ciclopirox derivatives. The model was validated by a Ciclopirox-property-matched decoy set. A principal component analysis (PCA) was also assessed to define the relationship of the predictive variable of the QSAR model. 24-derivatives with a ΔGB (-16.56±1.46 Kcal.mol-1) more than Ciclopirox was highlighted. A QSAR model with a predictive power of 88.99% (F-statistics = 9025.78, corrected df(25), Pr > F = 0.0001) was developed by four predictive descriptors (ATS1p, nCs, Hy, F08[C-C]). The model validation showed no predictive power for the decoy set (Q2 = 0). No significant correlation was observed between predictors. By directly attaching to the core protein carboxyl-terminal domain, Ciclopirox derivatives may be able to suppress HBV virus assembly and subsequent viral replication inhibition. Hydrophobic residue Phe23 is a critical amino acid in the ligand binding domain. These ligands share the same physicochemical properties that lead to the development of a robust QSAR mode. The same strategy may also be used for future drug discovery of viral inhibitors.
Collapse
Affiliation(s)
- Alireza Mohebbi
- Department of Virology, School of Medicine, Iran University of Medical Sciences, Tehran, Iran
- Vista Aria Rena Gene Inc., Golestan Province, Gorgan, Iran
| | - Touba Ghorbanzadeh
- Department of Microbiology, Tehran North Branch, Islamic Azad University of Tehran, Tehran, Iran
| | - Shabnam Naderifar
- Department of Biotechnology, Brandenburg Technology University, Senftenberg, Germany
| | - Fattaneh Khalaj
- Liver and Pancreatobiliary Diseases Research Center, Shariati Hospital, Tehran University of Medical Sciences, Tehran, Iran
- Digestive Diseases Research Center, Shariati Hospital, Tehran University of Medical Sciences, Tehran, Iran
| | | | - Ali Salehnia Sammak
- Department of Microbiology, Rasht Branch, Islamic Azad University, Rasht, Iran
| |
Collapse
|
8
|
Nakai Y, Miyakawa K, Yamaoka Y, Hatayama Y, Nishi M, Suzuki H, Kimura H, Takahashi H, Kimura Y, Ryo A. Generation and Utilization of a Monoclonal Antibody against Hepatitis B Virus Core Protein for a Comprehensive Interactome Analysis. Microorganisms 2022; 10:microorganisms10122381. [PMID: 36557634 PMCID: PMC9783060 DOI: 10.3390/microorganisms10122381] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2022] [Revised: 11/22/2022] [Accepted: 11/29/2022] [Indexed: 12/05/2022] Open
Abstract
Hepatitis B virus (HBV) core antigen (HBc) is a structural protein that forms the viral nucleocapsid and is involved in various steps of the viral replication cycle, but its role in the pathogenesis of HBV infection is still elusive. In this study, we generated a mouse monoclonal antibody (mAb) against HBc and used it in antibody-based in situ biotinylation analysis in order to identify host proteins that interact with HBc. HBc antigen was produced with a wheat germ cell-free protein synthesis system and used to immunize mice. Among the established hybridoma clones, a single clone (mAb #7) was selected and further characterized for its ability in the antibody-based in situ biotinylation analysis to collect host proteins that are in the vicinity of HBc. Using mass spectrometry, we identified 215 HBc-interacting host proteins, three of which bind HBc most significantly under hypoxic conditions. Our results indicate that mAb #7 can be used to systematically identify host proteins that interact with HBc under pathophysiological conditions, and thus may be useful to explore the molecular pathways involved in HBV-induced cytopathogenesis.
Collapse
Affiliation(s)
- Yusuke Nakai
- Department of Microbiology, Yokohama City University School of Medicine, Yokohama 236-0004, Japan
- Advanced Medical Research Center, Yokohama City University, Yokohama 236-0004, Japan
| | - Kei Miyakawa
- Department of Microbiology, Yokohama City University School of Medicine, Yokohama 236-0004, Japan
| | - Yutaro Yamaoka
- Department of Microbiology, Yokohama City University School of Medicine, Yokohama 236-0004, Japan
- Life Science Laboratory, Technology and Development Division, Kanto Chemical Co., Inc., Isehara 259-1146, Japan
| | - Yasuyoshi Hatayama
- Department of Microbiology, Yokohama City University School of Medicine, Yokohama 236-0004, Japan
- Advanced Medical Research Center, Yokohama City University, Yokohama 236-0004, Japan
| | - Mayuko Nishi
- Department of Microbiology, Yokohama City University School of Medicine, Yokohama 236-0004, Japan
| | - Hidefumi Suzuki
- Department of Molecular Biology, Yokohama City University School of Medicine, Yokohama 236-0004, Japan
| | - Hirokazu Kimura
- Department of Health Science, Gunma Paz University Graduate School, Takasaki 370-0006, Japan
| | - Hidehisa Takahashi
- Department of Molecular Biology, Yokohama City University School of Medicine, Yokohama 236-0004, Japan
| | - Yayoi Kimura
- Advanced Medical Research Center, Yokohama City University, Yokohama 236-0004, Japan
| | - Akihide Ryo
- Department of Microbiology, Yokohama City University School of Medicine, Yokohama 236-0004, Japan
- Advanced Medical Research Center, Yokohama City University, Yokohama 236-0004, Japan
- Correspondence: ; Tel.: +81-45-787-2602
| |
Collapse
|
9
|
Moharana M, Pattanayak SK, Khan F. Computational efforts to identify natural occurring compounds from phyllanthus niruri that target hepatitis B viral infections: DFT, docking and dynamics simulation study. J INDIAN CHEM SOC 2022. [DOI: 10.1016/j.jics.2022.100662] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/16/2022]
|
10
|
Callon M, Malär AA, Lecoq L, Dujardin M, Fogeron M, Wang S, Schledorn M, Bauer T, Nassal M, Böckmann A, Meier BH. Fast Magic‐Angle‐Spinning NMR Reveals the Evasive Hepatitis B Virus Capsid C‐Terminal Domain**. Angew Chem Int Ed Engl 2022; 61:e202201083. [PMID: 35653505 PMCID: PMC9400876 DOI: 10.1002/anie.202201083] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2022] [Indexed: 11/08/2022]
Abstract
Experimentally determined protein structures often feature missing domains. One example is the C‐terminal domain (CTD) of the hepatitis B virus capsid protein, a functionally central part of this assembly, crucial in regulating nucleic‐acid interactions, cellular trafficking, nuclear import, particle assembly and maturation. However, its structure remained elusive to all current techniques, including NMR. Here we show that the recently developed proton‐detected fast magic‐angle‐spinning solid‐state NMR at >100 kHz MAS allows one to detect this domain and unveil its structural and dynamic behavior. We describe the experimental framework used and compare the domain's behavior in different capsid states. The developed approaches extend solid‐state NMR observations to residues characterized by large‐amplitude motion on the microsecond timescale, and shall allow one to shed light on other flexible protein domains still lacking their structural and dynamic characterization.
Collapse
Affiliation(s)
| | | | - Lauriane Lecoq
- Molecular Microbiology and Structural Biochemistry (MMSB) UMR 5086 CNRS/Université de Lyon, Labex Ecofect 7 passage du Vercors 69367 Lyon France
| | - Marie Dujardin
- Molecular Microbiology and Structural Biochemistry (MMSB) UMR 5086 CNRS/Université de Lyon, Labex Ecofect 7 passage du Vercors 69367 Lyon France
| | - Marie‐Laure Fogeron
- Molecular Microbiology and Structural Biochemistry (MMSB) UMR 5086 CNRS/Université de Lyon, Labex Ecofect 7 passage du Vercors 69367 Lyon France
| | - Shishan Wang
- Molecular Microbiology and Structural Biochemistry (MMSB) UMR 5086 CNRS/Université de Lyon, Labex Ecofect 7 passage du Vercors 69367 Lyon France
| | | | - Thomas Bauer
- Physical Chemistry, ETH Zürich 8093 Zürich Switzerland
| | - Michael Nassal
- University Hospital Freiburg Dept. of Medicine II/Molecular Biology Medical Center University of Freiburg Freiburg Germany
| | - Anja Böckmann
- Molecular Microbiology and Structural Biochemistry (MMSB) UMR 5086 CNRS/Université de Lyon, Labex Ecofect 7 passage du Vercors 69367 Lyon France
| | - Beat H. Meier
- Physical Chemistry, ETH Zürich 8093 Zürich Switzerland
| |
Collapse
|
11
|
Callon M, Malär AA, Lecoq L, Dujardin M, Fogeron ML, Wang S, Schledorn M, Bauer T, Nassal M, Böckmann A, Meier BH. Fast Magic‐Angle‐Spinning NMR Reveals the Evasive Hepatitis B Virus Capsid C‐Terminal Domain. Angew Chem Int Ed Engl 2022. [DOI: 10.1002/ange.202201083] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Morgane Callon
- ETH Zurich D-CHAB: Eidgenossische Technische Hochschule Zurich Departement Chemie und Angewandte Biowissenschaften D-CHAB SWITZERLAND
| | - Alexander A. Malär
- ETH Zurich D-CHAB: Eidgenossische Technische Hochschule Zurich Departement Chemie und Angewandte Biowissenschaften D-CHAB SWITZERLAND
| | | | | | | | | | - Maarten Schledorn
- ETH Zurich D-CHAB: Eidgenossische Technische Hochschule Zurich Departement Chemie und Angewandte Biowissenschaften D-CHAB SWITZERLAND
| | - Thomas Bauer
- ETH Zurich D-CHAB: Eidgenossische Technische Hochschule Zurich Departement Chemie und Angewandte Biowissenschaften D-CHAB SWITZERLAND
| | - Michael Nassal
- University of Freiburg Hospital: Universitatsklinikum Freiburg Molecular Biology GERMANY
| | | | - Beat H Meier
- ETH Zurich D-CHAB: Eidgenossische Technische Hochschule Zurich Departement Chemie und Angewandte Biowissenschaften Department of Physical Chemistry Wolfgang-Pauli-Strasse 10 8093 Zürich SWITZERLAND
| |
Collapse
|
12
|
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.
Collapse
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
| |
Collapse
|
13
|
Ca2+/Calmodulin-Dependent Protein Kinase II Inhibits Hepatitis B Virus Replication from cccDNA via AMPK Activation and AKT/mTOR Suppression. Microorganisms 2022; 10:microorganisms10030498. [PMID: 35336076 PMCID: PMC8950817 DOI: 10.3390/microorganisms10030498] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2021] [Revised: 02/21/2022] [Accepted: 02/21/2022] [Indexed: 11/16/2022] Open
Abstract
Ca2+/calmodulin-dependent protein kinase II (CaMKII), which is involved in the calcium signaling pathway, is an important regulator of cancer cell proliferation, motility, growth, and metastasis. The effects of CaMKII on hepatitis B virus (HBV) replication have never been evaluated. Here, we found that phosphorylated, active CaMKII is reduced during HBV replication. Similar to other members of the AMPK/AKT/mTOR signaling pathway associated with HBV replication, CaMKII, which is associated with this pathway, was found to be a novel regulator of HBV replication. Overexpression of CaMKII reduced the expression of covalently closed circular DNA (cccDNA), HBV RNAs, and replicative intermediate (RI) DNAs while activating AMPK and inhibiting the AKT/mTOR signaling pathway. Findings in HBx-deficient mutant-transfected HepG2 cells showed that the CaMKII-mediated AMPK/AKT/mTOR signaling pathway was independent of HBx. Moreover, AMPK overexpression reduced HBV cccDNA, RNAs, and RI DNAs through CaMKII activation. Although AMPK acts downstream of CaMKII, AMPK overexpression altered CaMKII phosphorylation, suggesting that CaMKII and AMPK form a positive feedback loop. These results demonstrate that HBV replication suppresses CaMKII activity, and that CaMKII upregulation suppresses HBV replication from cccDNA via AMPK and the AKT/mTOR signaling pathway. Thus, activation or overexpression of CaMKII may be a new therapeutic target against HBV infection.
Collapse
|
14
|
Kim H, Ko C, Lee JY, Kim M. Current Progress in the Development of Hepatitis B Virus Capsid Assembly Modulators: Chemical Structure, Mode-of-Action and Efficacy. Molecules 2021; 26:molecules26247420. [PMID: 34946502 PMCID: PMC8705634 DOI: 10.3390/molecules26247420] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2021] [Revised: 11/24/2021] [Accepted: 12/02/2021] [Indexed: 12/15/2022] Open
Abstract
Hepatitis B virus (HBV) is a major causative agent of human hepatitis. Its viral genome comprises partially double-stranded DNA, which is complexed with viral polymerase within an icosahedral capsid consisting of a dimeric core protein. Here, we describe the effects of capsid assembly modulators (CAMs) on the geometric or kinetic disruption of capsid construction and the virus life cycle. We highlight classical, early-generation CAMs such as heteroaryldihydropyrimidines, phenylpropenamides or sulfamoylbenzamides, and focus on the chemical structure and antiviral efficacy of recently identified non-classical CAMs, which consist of carboxamides, aryl ureas, bithiazoles, hydrazones, benzylpyridazinones, pyrimidines, quinolines, dyes, and antimicrobial compounds. We summarize the therapeutic efficacy of four representative classical compounds with data from clinical phase 1 studies in chronic HBV patients. Most of these compounds are in phase 2 trials, either as monotherapy or in combination with approved nucleos(t)ides drugs or other immunostimulatory molecules. As followers of the early CAMs, the therapeutic efficacy of several non-classical CAMs has been evaluated in humanized mouse models of HBV infection. It is expected that these next-generation HBV CAMs will be promising candidates for a series of extended human clinical trials.
Collapse
Affiliation(s)
- Hyejin Kim
- Correspondence: (H.K.); (M.K.); Tel.: +82-42-860-7130 (H.K.); +82-42-860-7540 (M.K.)
| | | | | | - Meehyein Kim
- Correspondence: (H.K.); (M.K.); Tel.: +82-42-860-7130 (H.K.); +82-42-860-7540 (M.K.)
| |
Collapse
|
15
|
Lubyova B, Tikalova E, Krulova K, Hodek J, Zabransky A, Hirsch I, Weber J. ATM-Dependent Phosphorylation of Hepatitis B Core Protein in Response to Genotoxic Stress. Viruses 2021; 13:v13122438. [PMID: 34960710 PMCID: PMC8705010 DOI: 10.3390/v13122438] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2021] [Revised: 11/29/2021] [Accepted: 12/02/2021] [Indexed: 12/31/2022] Open
Abstract
Chronic hepatitis caused by infection with the Hepatitis B virus is a life-threatening condition. In fact, 1 million people die annually due to liver cirrhosis or hepatocellular carcinoma. Recently, several studies demonstrated a molecular connection between the host DNA damage response (DDR) pathway and HBV replication and reactivation. Here, we investigated the role of Ataxia-telangiectasia-mutated (ATM) and Ataxia telangiectasia and Rad3-related (ATR) PI3-kinases in phosphorylation of the HBV core protein (HBc). We determined that treatment of HBc-expressing hepatocytes with genotoxic agents, e.g., etoposide or hydrogen peroxide, activated the host ATM-Chk2 pathway, as determined by increased phosphorylation of ATM at Ser1981 and Chk2 at Thr68. The activation of ATM led, in turn, to increased phosphorylation of cytoplasmic HBc at serine-glutamine (SQ) motifs located in its C-terminal domain. Conversely, down-regulation of ATM using ATM-specific siRNAs or inhibitor effectively reduced etoposide-induced HBc phosphorylation. Detailed mutation analysis of S-to-A HBc mutants revealed that S170 (S168 in a 183-aa HBc variant) is the primary site targeted by ATM-regulated phosphorylation. Interestingly, mutation of two major phosphorylation sites involving serines at positions 157 and 164 (S155 and S162 in a 183-aa HBc variant) resulted in decreased etoposide-induced phosphorylation, suggesting that the priming phosphorylation at these serine-proline (SP) sites is vital for efficient phosphorylation of SQ motifs. Notably, the mutation of S172 (S170 in a 183-aa HBc variant) had the opposite effect and resulted in massively up-regulated phosphorylation of HBc, particularly at S170. Etoposide treatment of HBV infected HepG2-NTCP cells led to increased levels of secreted HBe antigen and intracellular HBc protein. Together, our studies identified HBc as a substrate for ATM-mediated phosphorylation and mapped the phosphorylation sites. The increased expression of HBc and HBe antigens in response to genotoxic stress supports the idea that the ATM pathway may provide growth advantage to the replicating virus.
Collapse
Affiliation(s)
- Barbora Lubyova
- IOCB Gilead Research Center, Institute of Organic Chemistry and Biochemistry of the Czech Academy of Sciences, 160 00 Prague, Czech Republic; (E.T.); (K.K.); (J.H.); (A.Z.); (I.H.)
- Correspondence: (B.L.); (J.W.)
| | - Eva Tikalova
- IOCB Gilead Research Center, Institute of Organic Chemistry and Biochemistry of the Czech Academy of Sciences, 160 00 Prague, Czech Republic; (E.T.); (K.K.); (J.H.); (A.Z.); (I.H.)
| | - Kristyna Krulova
- IOCB Gilead Research Center, Institute of Organic Chemistry and Biochemistry of the Czech Academy of Sciences, 160 00 Prague, Czech Republic; (E.T.); (K.K.); (J.H.); (A.Z.); (I.H.)
| | - Jan Hodek
- IOCB Gilead Research Center, Institute of Organic Chemistry and Biochemistry of the Czech Academy of Sciences, 160 00 Prague, Czech Republic; (E.T.); (K.K.); (J.H.); (A.Z.); (I.H.)
| | - Ales Zabransky
- IOCB Gilead Research Center, Institute of Organic Chemistry and Biochemistry of the Czech Academy of Sciences, 160 00 Prague, Czech Republic; (E.T.); (K.K.); (J.H.); (A.Z.); (I.H.)
| | - Ivan Hirsch
- IOCB Gilead Research Center, Institute of Organic Chemistry and Biochemistry of the Czech Academy of Sciences, 160 00 Prague, Czech Republic; (E.T.); (K.K.); (J.H.); (A.Z.); (I.H.)
- Department of Genetics and Microbiology, Faculty of Science, Charles University, BIOCEV, 252 50 Vestec, Czech Republic
| | - Jan Weber
- IOCB Gilead Research Center, Institute of Organic Chemistry and Biochemistry of the Czech Academy of Sciences, 160 00 Prague, Czech Republic; (E.T.); (K.K.); (J.H.); (A.Z.); (I.H.)
- Correspondence: (B.L.); (J.W.)
| |
Collapse
|
16
|
Binding of a Pocket Factor to Hepatitis B Virus Capsids Changes the Rotamer Conformation of Phenylalanine 97. Viruses 2021; 13:v13112115. [PMID: 34834922 PMCID: PMC8618838 DOI: 10.3390/v13112115] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2021] [Revised: 10/13/2021] [Accepted: 10/15/2021] [Indexed: 12/26/2022] Open
Abstract
(1) Background: During maturation of the Hepatitis B virus, a viral polymerase inside the capsid transcribes a pre-genomic RNA into a partly double stranded DNA-genome. This is followed by envelopment with surface proteins inserted into a membrane. Envelopment is hypothetically regulated by a structural signal that reports the maturation state of the genome. NMR data suggest that such a signal can be mimicked by the binding of the detergent Triton X 100 to hydrophobic pockets in the capsid spikes. (2) Methods: We have used electron cryo-microscopy and image processing to elucidate the structural changes that are concomitant with the binding of Triton X 100. (3) Results: Our maps show that Triton X 100 binds with its hydrophobic head group inside the pocket. The hydrophilic tail delineates the outside of the spike and is coordinated via Lys-96. The binding of Triton X 100 changes the rotamer conformation of Phe-97 in helix 4, which enables a π-stacking interaction with Trp-62 in helix 3. Similar changes occur in mutants with low secretion phenotypes (P5T and L60V) and in a mutant with a pre-mature secretion phenotype (F97L). (4) Conclusion: Binding of Triton X 100 is unlikely to mimic structural maturation because mutants with different secretion phenotypes show similar structural responses.
Collapse
|
17
|
Conformational Plasticity of Hepatitis B Core Protein Spikes Promotes Peptide Binding Independent of the Secretion Phenotype. Microorganisms 2021; 9:microorganisms9050956. [PMID: 33946808 PMCID: PMC8145704 DOI: 10.3390/microorganisms9050956] [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: 04/03/2021] [Revised: 04/22/2021] [Accepted: 04/26/2021] [Indexed: 12/31/2022] Open
Abstract
Hepatitis B virus is a major human pathogen, which forms enveloped virus particles. During viral maturation, membrane-bound hepatitis B surface proteins package hepatitis B core protein capsids. This process is intercepted by certain peptides with an “LLGRMKG” motif that binds to the capsids at the tips of dimeric spikes. With microcalorimetry, electron cryo microscopy and peptide microarray-based screens, we have characterized the structural and thermodynamic properties of peptide binding to hepatitis B core protein capsids with different secretion phenotypes. The peptide “GSLLGRMKGA” binds weakly to hepatitis B core protein capsids and mutant capsids with a premature (F97L) or low-secretion phenotype (L60V and P5T). With electron cryo microscopy, we provide novel structures for L60V and P5T and demonstrate that binding occurs at the tips of the spikes at the dimer interface, splaying the helices apart independent of the secretion phenotype. Peptide array screening identifies “SLLGRM” as the core binding motif. This shortened motif binds only to one of the two spikes in the asymmetric unit of the capsid and induces a much smaller conformational change. Altogether, these comprehensive studies suggest that the tips of the spikes act as an autonomous binding platform that is unaffected by mutations that affect secretion phenotypes.
Collapse
|
18
|
Early Steps of Hepatitis B Life Cycle: From Capsid Nuclear Import to cccDNA Formation. Viruses 2021; 13:v13050757. [PMID: 33925977 PMCID: PMC8145197 DOI: 10.3390/v13050757] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2021] [Revised: 04/22/2021] [Accepted: 04/23/2021] [Indexed: 02/06/2023] Open
Abstract
Hepatitis B virus (HBV) remains a major public health concern, with more than 250 million chronically infected people who are at high risk of developing liver diseases, including cirrhosis and hepatocellular carcinoma. Although antiviral treatments efficiently control virus replication and improve liver function, they cannot cure HBV infection. Viral persistence is due to the maintenance of the viral circular episomal DNA, called covalently closed circular DNA (cccDNA), in the nuclei of infected cells. cccDNA not only resists antiviral therapies, but also escapes innate antiviral surveillance. This viral DNA intermediate plays a central role in HBV replication, as cccDNA is the template for the transcription of all viral RNAs, including pregenomic RNA (pgRNA), which in turn feeds the formation of cccDNA through a step of reverse transcription. The establishment and/or expression of cccDNA is thus a prime target for the eradication of HBV. In this review, we provide an update on the current knowledge on the initial steps of HBV infection, from the nuclear import of the nucleocapsid to the formation of the cccDNA.
Collapse
|
19
|
Shih C, Wu SY, Chou SF, Yuan TTT. Virion Secretion of Hepatitis B Virus Naturally Occurring Core Antigen Variants. Cells 2020; 10:cells10010043. [PMID: 33396864 PMCID: PMC7823318 DOI: 10.3390/cells10010043] [Citation(s) in RCA: 4] [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: 11/08/2020] [Revised: 12/21/2020] [Accepted: 12/28/2020] [Indexed: 02/07/2023] Open
Abstract
In natural infection, hepatitis B virus (HBV) core protein (HBc) accumulates frequent mutations. The most frequent HBc variant in chronic hepatitis B patients is mutant 97L, changing from an isoleucine or phenylalanine to a leucine (L) at HBc amino acid 97. One dogma in the HBV research field is that wild type HBV secretes predominantly virions containing mature double-stranded DNA genomes. Immature genomes, containing single-stranded RNA or DNA, do not get efficiently secreted until reaching genome maturity. Interestingly, HBc variant 97L does not follow this dogma in virion secretion. Instead, it exhibits an immature secretion phenotype, which preferentially secretes virions containing immature genomes. Other aberrant behaviors in virion secretion were also observed in different naturally occurring HBc variants. A hydrophobic pocket around amino acid 97 was identified by bioinformatics, genetic analysis, and cryo-EM. We postulated that this hydrophobic pocket could mediate the transduction of the genome maturation signal for envelopment from the capsid interior to its surface. Virion morphogenesis must involve interactions between HBc, envelope proteins (HBsAg) and host factors, such as components of ESCRT (endosomal sorting complex required for transport). Immature secretion can be offset by compensatory mutations, occurring at other positions in HBc or HBsAg. Recently, we demonstrated in mice that the persistence of intrahepatic HBV DNA is related to virion secretion regulated by HBV genome maturity. HBV virion secretion could be an antiviral drug target.
Collapse
Affiliation(s)
- Chiaho Shih
- Graduate Institute of Medicine, Kaohsiung Medical University, Kaohsiung 80708, Taiwan
- Institute of Biomedical Sciences, Academia Sinica, Taipei 11529, Taiwan
- Correspondence: (C.S.); (T.-T.T.Y.)
| | - Szu-Yao Wu
- Chimera Bioscience Inc., No. 18 Siyuan St., Zhongzheng Dist., Taipei 10087, Taiwan;
| | - Shu-Fan Chou
- Department of Microbiology, Harvard Medical School, Boston, MA 02115, USA;
| | - Ta-Tung Thomas Yuan
- TFBS Bioscience, Inc. 3F, No. 103, Ln 169, Kangning St., Xizhi Dist., New Taipei City 221, Taiwan
- Correspondence: (C.S.); (T.-T.T.Y.)
| |
Collapse
|
20
|
Bernacchi S. Special Issue "Function and Structure of Viral Ribonucleoproteins Complexes". Viruses 2020; 12:v12121355. [PMID: 33256140 PMCID: PMC7760632 DOI: 10.3390/v12121355] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2020] [Accepted: 11/24/2020] [Indexed: 12/12/2022] Open
Affiliation(s)
- Serena Bernacchi
- Architecture et Réactivité de l'ARN-CNRS UPR 9002, Université de Strasbourg, Institut de Biologie Moléculaire et Cellulaire, 67084 Strasbourg, France
| |
Collapse
|