1
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Takahashi M, Nishizawa T, Nishizono A, Kawakami M, Sato Y, Kawakami K, Irokawa M, Tamaru T, Miyazaki S, Shimada M, Ozaki H, Primadharsini PP, Nagashima S, Murata K, Okamoto H. Recent decline in hepatitis E virus prevalence among wild boars in Japan: Probably due to countermeasures implemented in response to outbreaks of classical swine fever virus infection. Virus Res 2024; 348:199438. [PMID: 39013518 PMCID: PMC11315222 DOI: 10.1016/j.virusres.2024.199438] [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: 05/22/2024] [Revised: 07/08/2024] [Accepted: 07/13/2024] [Indexed: 07/18/2024]
Abstract
Previous studies have emphasized the necessity of surveillance and control measures for hepatitis E virus (HEV) infection in wild boars, an important reservoir of HEV. To assess the current situation of HEV infection in wild boars in Japan, this study investigated the prevalence and genetic diversity of HEV among wild boars captured in 16 prefectures of Japan during 2018-2023. Serum samples from 968 wild boars were examined for anti-HEV IgG antibodies and HEV RNA. The prevalence of anti-HEV IgG varied geographically from 0 % to 35.0 %. HEV RNA was detected in 3.6 % of boars, with prevalence varying by prefecture from 0 % to 22.2 %. Genotype 3 was the most prevalent genotype (91.9 %), followed by genotype 4 (5.4 %), with one strain closely related to genotype 6. The prevalence of HEV infection among wild boars decreased from 2018/2019 to 2022/2023 with significant declines in levels of anti-HEV IgG antibodies (14.5 % vs. 6.2 %, P < 0.0001) and HEV RNA (7.6 % vs. 1.5 %, P < 0.0001). Regional analysis showed varying trends, with no HEV RNA-positive boars found in several regions in recent years. A plausible factor contributing to the decline in HEV infection is the application of countermeasures, including installing fences to prevent intrusion into pig farms, implemented in response to the emergence of classical swine fever virus (CSFV) infection in wild boars and domestic pigs, with incidents reported annually since 2018. Further investigation is warranted to explore the association between countermeasures to CSFV infection and the decrease in HEV infection among wild boars.
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Affiliation(s)
- Masaharu Takahashi
- Division of Virology, Department of Infection and Immunity, Jichi Medical University School of Medicine, Shimotsuke, Tochigi 329-0498, Japan
| | - Tsutomu Nishizawa
- Division of Virology, Department of Infection and Immunity, Jichi Medical University School of Medicine, Shimotsuke, Tochigi 329-0498, Japan
| | - Akira Nishizono
- Department of Microbiology, Faculty of Medicine and Research Center for Global and Local Infectious Diseases, Oita University, Yufu, Oita 879-5593, Japan
| | - Manri Kawakami
- Center for Liver Disease, Okayama Saiseikai General Hospital, Okayama, Okayama 700-8511, Japan
| | - Yukihiro Sato
- Department of Internal Medicine, Kamiichi General Hospital, Nakaniikawa-gun, Toyama 930-0391, Japan
| | - Kazunori Kawakami
- Ayagawa National Health Insurance Sue Hospital, Ayauta-gun, Kagawa 761-2103, Japan
| | | | - Tomoko Tamaru
- Nishiizu Ken-ikukai Hospital, Kamo-gun, Shizuoka 410-3514, Japan
| | - Shinichi Miyazaki
- Department of Gastroenterology, Tottori Seikyo Hospital, Tottori, Tottori 680-0833, Japan
| | - Mizuho Shimada
- Health Care Center, Jichi Medical University Hospital, Shimotsuke, Tochigi 329-0434, Japan
| | | | - Putu Prathiwi Primadharsini
- Division of Virology, Department of Infection and Immunity, Jichi Medical University School of Medicine, Shimotsuke, Tochigi 329-0498, Japan
| | - Shigeo Nagashima
- Division of Virology, Department of Infection and Immunity, Jichi Medical University School of Medicine, Shimotsuke, Tochigi 329-0498, Japan
| | - Kazumoto Murata
- Division of Virology, Department of Infection and Immunity, Jichi Medical University School of Medicine, Shimotsuke, Tochigi 329-0498, Japan
| | - Hiroaki Okamoto
- Division of Virology, Department of Infection and Immunity, Jichi Medical University School of Medicine, Shimotsuke, Tochigi 329-0498, Japan.
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2
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Wißing MH, Meister TL, Nocke MK, Gömer A, Masovic M, Knegendorf L, Brüggemann Y, Bader V, Siddharta A, Bock CT, Ploss A, Kenney SP, Winklhofer KF, Behrendt P, Wedemeyer H, Steinmann E, Todt D. Genetic determinants of host- and virus-derived insertions for hepatitis E virus replication. Nat Commun 2024; 15:4855. [PMID: 38844458 PMCID: PMC11156872 DOI: 10.1038/s41467-024-49219-8] [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: 10/06/2023] [Accepted: 05/24/2024] [Indexed: 06/09/2024] Open
Abstract
Hepatitis E virus (HEV) is a long-neglected RNA virus and the major causative agent of acute viral hepatitis in humans. Recent data suggest that HEV has a very heterogeneous hypervariable region (HVR), which can tolerate major genomic rearrangements. In this study, we identify insertions of previously undescribed sequence snippets in serum samples of a ribavirin treatment failure patient. These insertions increase viral replication while not affecting sensitivity towards ribavirin in a subgenomic replicon assay. All insertions contain a predicted nuclear localization sequence and alanine scanning mutagenesis of lysine residues in the HVR influences viral replication. Sequential replacement of lysine residues additionally alters intracellular localization in a fluorescence dye-coupled construct. Furthermore, distinct sequence patterns outside the HVR are identified as viral determinants that recapitulate the enhancing effect. In conclusion, patient-derived insertions can increase HEV replication and synergistically acting viral determinants in and outside the HVR are described. These results will help to understand the underlying principles of viral adaptation by viral- and host-sequence snatching during the clinical course of infection.
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Affiliation(s)
| | - Toni Luise Meister
- Department for Molecular and Medical Medicine, Ruhr University Bochum, Bochum, Germany
- Institute for Infection Research and Vaccine Development (IIRVD), Centre for Internal Medicine, University Medical Centre Hamburg-Eppendorf (UKE), Hamburg, Germany
- Department for Clinical Immunology of Infectious Diseases, Bernhard Nocht Institute for Tropical Medicine (BNITM), Hamburg, Germany
- German Centre for Infection Research (DZIF), Partner site Hamburg-Lübeck-Borstel-Riems, Hamburg, Germany
| | - Maximilian Klaus Nocke
- Department for Molecular and Medical Medicine, Ruhr University Bochum, Bochum, Germany
- European Virus Bioinformatics Center (EVBC), Jena, Germany
| | - André Gömer
- Department for Molecular and Medical Medicine, Ruhr University Bochum, Bochum, Germany
| | - Mejrema Masovic
- Department for Molecular and Medical Medicine, Ruhr University Bochum, Bochum, Germany
| | - Leonard Knegendorf
- Institute for Experimental Virology, TWINCORE Centre for Experimental and Clinical Infection Research, a Joint Venture between the Medical School Hannover (MHH) and the Helmholtz Centre for Infection Research (HZI), Hannover, Germany
- Hannover Medical School, Institute for Medical Microbiology and Hospital Epidemiology, Hannover, Germany
| | - Yannick Brüggemann
- Department for Molecular and Medical Medicine, Ruhr University Bochum, Bochum, Germany
| | - Verian Bader
- Department of Molecular Cell Biology, Institute of Biochemistry and Pathobiochemistry, Ruhr University Bochum, Bochum, Germany
- Department of Biochemistry of Neurodegenerative Diseases, Institute of Biochemistry and Pathobiochemistry, Ruhr University Bochum, Bochum, Germany
| | - Anindya Siddharta
- Institute for Experimental Virology, TWINCORE Centre for Experimental and Clinical Infection Research, a Joint Venture between the Medical School Hannover (MHH) and the Helmholtz Centre for Infection Research (HZI), Hannover, Germany
| | - Claus-Thomas Bock
- Division of Viral Gastroenteritis and Hepatitis Pathogens and Enteroviruses, Department of Infectious Diseases, Robert Koch Institute, Berlin, Germany
| | - Alexander Ploss
- Department of Molecular Biology, Princeton University, Princeton, NJ, USA
| | - Scott P Kenney
- Center for Food Animal Health, Departments of Animal Sciences and Veterinary Preventive Medicine, The Ohio State University, Wooster, OH, 43210, USA
| | - Konstanze F Winklhofer
- Department of Molecular Cell Biology, Institute of Biochemistry and Pathobiochemistry, Ruhr University Bochum, Bochum, Germany
- Cluster of Excellence RESOLV, Bochum, Germany
| | - Patrick Behrendt
- Institute for Experimental Virology, TWINCORE Centre for Experimental and Clinical Infection Research, a Joint Venture between the Medical School Hannover (MHH) and the Helmholtz Centre for Infection Research (HZI), Hannover, Germany
- Department of Gastroenterology, Hepatology and Endocrinology, Hannover Medical School, Hannover, Germany
- German Center for Infectious Disease Research (DZIF); Partner Sites Hannover-Braunschweig, Braunschweig, Germany
| | - Heiner Wedemeyer
- Department of Gastroenterology, Hepatology and Endocrinology, Hannover Medical School, Hannover, Germany
- German Center for Infectious Disease Research (DZIF); Partner Sites Hannover-Braunschweig, Braunschweig, Germany
- Excellence Cluster 2155 RESIST, Hannover Medical School, Hannover, Germany, Braunschweig, Germany
| | - Eike Steinmann
- Department for Molecular and Medical Medicine, Ruhr University Bochum, Bochum, Germany.
- German Centre for Infection Research (DZIF), External Partner Site, Bochum, Germany.
| | - Daniel Todt
- Department for Molecular and Medical Medicine, Ruhr University Bochum, Bochum, Germany.
- European Virus Bioinformatics Center (EVBC), Jena, Germany.
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3
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Feng Z. Cathepsins prime hepatitis E virus for cell entry. Hepatology 2024:01515467-990000000-00887. [PMID: 38776183 DOI: 10.1097/hep.0000000000000936] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/10/2024] [Accepted: 05/10/2024] [Indexed: 05/24/2024]
Affiliation(s)
- Zongdi Feng
- Center for Vaccines and Immunity, The Abigail Wexner Research Institute at Nationwide Children's Hospital, Columbus, Ohio, USA
- The Ohio State University College of Medicine, Columbus, Ohio, USA
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4
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Oechslin N, Da Silva N, Ankavay M, Moradpour D, Gouttenoire J. A genome-wide CRISPR/Cas9 screen identifies a role for Rab5A and early endosomes in hepatitis E virus replication. Proc Natl Acad Sci U S A 2023; 120:e2307423120. [PMID: 38109552 PMCID: PMC10756275 DOI: 10.1073/pnas.2307423120] [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: 05/08/2023] [Accepted: 11/17/2023] [Indexed: 12/20/2023] Open
Abstract
Hepatitis E virus (HEV) is a major cause of acute hepatitis worldwide. As the other positive-strand RNA viruses, it is believed to replicate its genome in a membrane-associated replication complex. However, current understanding of the host factors required for productive HEV infection is limited and the site as well as the composition of the HEV replication complex are still poorly characterized. To identify host factors required for HEV RNA replication, we performed a genome-wide CRISPR/Cas9 screen in permissive human cell lines harboring subgenomic HEV replicons allowing for positive and negative selection. Among the validated candidates, Ras-related early endosomal protein Rab5A was selected for further characterization. siRNA-mediated silencing of Rab5A and its effectors APPL1 and EEA1, but not of the late and recycling endosome components Rab7A and Rab11A, respectively, significantly reduced HEV RNA replication. Furthermore, pharmacological inhibition of Rab5A and of dynamin-2, required for the formation of early endosomes, resulted in a dose-dependent decrease of HEV RNA replication. Colocalization studies revealed close proximity of Rab5A, the HEV ORF1 protein, corresponding to the viral replicase, as well as HEV positive- and negative-strand RNA. In conclusion, we successfully exploited CRISPR/Cas9 and selectable subgenomic replicons to identify host factors of a noncytolytic virus. This approach revealed a role for Rab5A and early endosomes in HEV RNA replication, likely by serving as a scaffold for the establishment of functional replication complexes. Our findings yield insights into the HEV life cycle and the virus-host interactions required for productive infection.
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Affiliation(s)
- Noémie Oechslin
- Division of Gastroenterology and Hepatology, Lausanne University Hospital and University of Lausanne, Lausanne1011, Switzerland
| | - Nathalie Da Silva
- Division of Gastroenterology and Hepatology, Lausanne University Hospital and University of Lausanne, Lausanne1011, Switzerland
| | - Maliki Ankavay
- Division of Gastroenterology and Hepatology, Lausanne University Hospital and University of Lausanne, Lausanne1011, Switzerland
| | - Darius Moradpour
- Division of Gastroenterology and Hepatology, Lausanne University Hospital and University of Lausanne, Lausanne1011, Switzerland
| | - Jérôme Gouttenoire
- Division of Gastroenterology and Hepatology, Lausanne University Hospital and University of Lausanne, Lausanne1011, Switzerland
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5
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Buchanan FJT, Chen S, Harris M, Herod MR. The hepatitis E virus ORF1 hypervariable region confers partial cyclophilin dependency. J Gen Virol 2023; 104:001919. [PMID: 37942835 PMCID: PMC10768694 DOI: 10.1099/jgv.0.001919] [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: 12/06/2022] [Accepted: 10/27/2023] [Indexed: 11/10/2023] Open
Abstract
Hepatitis E virus (HEV) is an emerging pathogen responsible for more than 20 million cases of acute hepatitis globally per annum. Healthy individuals typically have a self-limiting infection, but mortality rates in some populations such as pregnant women can reach 30 %. A detailed understanding of the virus lifecycle is lacking, mainly due to limitations in experimental systems. In this regard, the cyclophilins are an important family of proteins that have peptidyl-prolyl isomerase activity and play roles in the replication of a number of positive-sense RNA viruses, including hepatotropic viruses such as hepatitis C virus (HCV). Cyclophilins A and B (CypA/B) are the two most abundant Cyps in hepatocytes and are therefore potential targets for pan-viral therapeutics. Here, we investigated the importance of CypA and CypB for HEV genome replication using sub-genomic replicons. Using a combination of pharmacological inhibition by cyclosporine A (CsA), and silencing by small hairpin RNA we find that CypA and CypB are not essential for HEV replication. However, we find that silencing of CypB reduces replication of some HEV isolates in some cells. Furthermore, sensitivity to Cyp silencing appears to be partly conferred by the sequence within the hypervariable region of the viral polyprotein. These data suggest HEV is atypical in its requirements for cyclophilin for viral genome replication and that this phenomenon could be genotype- and sequence-specific.
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Affiliation(s)
- Frazer J. T. Buchanan
- School of Molecular and Cellular Biology, Faculty of Biological Sciences and Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds, LS2 9JT, UK
| | - Shucheng Chen
- Department of Paediatrics, Harvard Medical School, Boston, Massachusetts, USA
| | - Mark Harris
- School of Molecular and Cellular Biology, Faculty of Biological Sciences and Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds, LS2 9JT, UK
| | - Morgan R. Herod
- School of Molecular and Cellular Biology, Faculty of Biological Sciences and Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds, LS2 9JT, UK
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6
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Nagashima S, Primadharsini PP, Nishiyama T, Takahashi M, Murata K, Okamoto H. Development of a HiBiT-tagged reporter hepatitis E virus and its utility as an antiviral drug screening platform. J Virol 2023; 97:e0050823. [PMID: 37681960 PMCID: PMC10537679 DOI: 10.1128/jvi.00508-23] [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: 04/05/2023] [Accepted: 06/15/2023] [Indexed: 09/09/2023] Open
Abstract
Previously, we developed an infectious hepatitis E virus (HEV) harboring the nanoKAZ gene in the hypervariable region of the open reading frame 1 (ORF1) of the HEV3b (JE03-1760F/P10) genome and demonstrated the usefulness for screening anti-HEV drugs that inhibit the early infection process. In the present study, we constructed another reporter HEV (HEV3b-HiBiT) by placing a minimized HiBiT tag derived from NanoLuc luciferase at the 3'-end of the viral capsid (ORF2) coding sequence. It replicated efficiently in PLC/PRF/5 cells, produced membrane-associated particles identical to those of the parental virus, and was genetically stable and infectious. The HiBiT tag was fused to both secreted ORF2s (ORF2s-HiBiT) and ORF2c capsid protein (ORF2c-HiBiT). The ORF2c-HiBiT formed membrane-associated HEV particles (eHEV3b-HiBiT). By treating these particles with digitonin, we demonstrated that the HiBiT tag was expressed on the surface of capsid and was present inside the lipid membrane. To simplify the measurement of luciferase activity and provide a more convenient screening platform, we constructed an ORF2s-defective mutant (HEV3b-HiBiT/ΔORF2s) in which the secreted ORF2s are suppressed. We used this system to evaluate the effects of introducing small interfering RNAs and treatment with an inhibitor or accelerator of exosomal release on HEV egress and demonstrated that the effects on virus release can readily be analyzed. Therefore, HEV3b-HiBiT and HEV3b-HiBiT/ΔORF2s reporters may be useful for investigating the virus life cycle and can serve as a more convenient screening platform to search for candidate drugs targeting the late stage of HEV infection such as particle formation and release. IMPORTANCE The construction of recombinant infectious viruses harboring a stable luminescence reporter gene is essential for investigations of the viral life cycle, such as viral replication and pathogenesis, and the development of novel antiviral drugs. However, it is difficult to maintain the stability of a large foreign gene inserted into the viral genome. In the present study, we successfully generated a recombinant HEV harboring the 11-amino acid HiBiT tag in the ORF2 coding region and demonstrated the infectivity, efficient virus growth, particle morphology, and genetic stability, suggesting that this recombinant HEV is useful for in vitro assays. Furthermore, this system can serve as a more convenient screening platform for anti-HEV drugs. Thus, an infectious recombinant HEV is a powerful approach not only for elucidating the molecular mechanisms of the viral life cycle but also for the screening and development of novel antiviral agents.
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Affiliation(s)
- Shigeo Nagashima
- Division of Virology, Department of Infection and Immunity, Jichi Medical University School of Medicine, Tochigi, Japan
| | - Putu Prathiwi Primadharsini
- Division of Virology, Department of Infection and Immunity, Jichi Medical University School of Medicine, Tochigi, Japan
| | - Takashi Nishiyama
- Division of Virology, Department of Infection and Immunity, Jichi Medical University School of Medicine, Tochigi, Japan
| | - Masaharu Takahashi
- Division of Virology, Department of Infection and Immunity, Jichi Medical University School of Medicine, Tochigi, Japan
| | - Kazumoto Murata
- Division of Virology, Department of Infection and Immunity, Jichi Medical University School of Medicine, Tochigi, Japan
| | - Hiroaki Okamoto
- Division of Virology, Department of Infection and Immunity, Jichi Medical University School of Medicine, Tochigi, Japan
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7
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Primadharsini PP, Nagashima S, Nishiyama T, Okamoto H. Three Distinct Reporter Systems of Hepatitis E Virus and Their Utility as Drug Screening Platforms. Viruses 2023; 15:1989. [PMID: 37896767 PMCID: PMC10611241 DOI: 10.3390/v15101989] [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: 09/09/2023] [Revised: 09/20/2023] [Accepted: 09/22/2023] [Indexed: 10/29/2023] Open
Abstract
The hepatitis E virus (HEV) is increasingly acknowledged as the primary cause of acute hepatitis. While most HEV infections are self-limiting, cases of chronic infection and fulminant hepatitis necessitate the administration of anti-HEV medications. However, there is a lack of specific antiviral drugs designed for HEV, and the currently available drug (ribavirin) has been associated with significant adverse effects. The development of innovative antiviral drugs involves targeting distinct steps within the viral life cycle: the early step (attachment and internalization), middle step (translation and RNA replication), and late step (virus particle formation and virion release). We recently established three HEV reporter systems, each covering one or two of these steps. Using these reporter systems, we identified various potential drug candidates that target different steps of the HEV life cycle. Through rigorous in vitro testing using our robust cell culture system with the genotype 3 HEV strain (JE03-1760F/P10), we confirmed the efficacy of these drugs, when used alone or in combination with existing anti-HEV drugs. This underscores their significance in the quest for an effective anti-HEV treatment. In the present review, we discuss the development of the three reporter systems, their applications in drug screening, and their potential to advance our understanding of the incompletely elucidated HEV life cycle.
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Affiliation(s)
- Putu Prathiwi Primadharsini
- Division of Virology, Department of Infection and Immunity, Jichi Medical University School of Medicine, 3311-1 Yakushiji, Shimotsuke 329-0498, Tochigi, Japan; (P.P.P.); (S.N.)
| | - Shigeo Nagashima
- Division of Virology, Department of Infection and Immunity, Jichi Medical University School of Medicine, 3311-1 Yakushiji, Shimotsuke 329-0498, Tochigi, Japan; (P.P.P.); (S.N.)
| | - Takashi Nishiyama
- Laboratory of Membrane Proteins, Research Division for Quantitative Life Sciences, Institute for Quantitative Biosciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-0032, Japan;
| | - Hiroaki Okamoto
- Division of Virology, Department of Infection and Immunity, Jichi Medical University School of Medicine, 3311-1 Yakushiji, Shimotsuke 329-0498, Tochigi, Japan; (P.P.P.); (S.N.)
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8
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Pierce DM, Buchanan FJT, Macrae FL, Mills JT, Cox A, Abualsaoud KM, Ward JC, Ariëns RAS, Harris M, Stonehouse NJ, Herod MR. Thrombin cleavage of the hepatitis E virus polyprotein at multiple conserved locations is required for genome replication. PLoS Pathog 2023; 19:e1011529. [PMID: 37478143 PMCID: PMC10395923 DOI: 10.1371/journal.ppat.1011529] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2022] [Accepted: 07/03/2023] [Indexed: 07/23/2023] Open
Abstract
The genomes of positive-sense RNA viruses encode polyproteins that are essential for mediating viral replication. These viral polyproteins must undergo proteolysis (also termed polyprotein processing) to generate functional protein units. This proteolysis can be performed by virally-encoded proteases as well as host cellular proteases, and is generally believed to be a key step in regulating viral replication. Hepatitis E virus (HEV) is a leading cause of acute viral hepatitis. The positive-sense RNA genome is translated to generate a polyprotein, termed pORF1, which is necessary and sufficient for viral genome replication. However, the mechanism of polyprotein processing in HEV remains to be determined. In this study, we aimed to understand processing of this polyprotein and its role in viral replication using a combination of in vitro translation experiments and HEV sub-genomic replicons. Our data suggest no evidence for a virally-encoded protease or auto-proteolytic activity, as in vitro translation predominantly generates unprocessed viral polyprotein precursors. However, seven cleavage sites within the polyprotein (suggested by bioinformatic analysis) are susceptible to the host cellular protease, thrombin. Using two sub-genomic replicon systems, we demonstrate that mutagenesis of these sites prevents replication, as does pharmacological inhibition of serine proteases including thrombin. Overall, our data supports a model where HEV uses host proteases to support replication and could have evolved to be independent of a virally-encoded protease for polyprotein processing.
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Affiliation(s)
- Danielle M Pierce
- School of Molecular and Cellular Biology, Faculty of Biological Sciences and Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds, United Kingdom
| | - Frazer J T Buchanan
- School of Molecular and Cellular Biology, Faculty of Biological Sciences and Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds, United Kingdom
| | - Fraser L Macrae
- Discovery and Translational Science Department, Leeds Institute of Cardiovascular and Metabolic Medicine, University of Leeds, Leeds, United Kingdom
| | - Jake T Mills
- School of Molecular and Cellular Biology, Faculty of Biological Sciences and Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds, United Kingdom
| | - Abigail Cox
- School of Molecular and Cellular Biology, Faculty of Biological Sciences and Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds, United Kingdom
| | - Khadijah M Abualsaoud
- School of Molecular and Cellular Biology, Faculty of Biological Sciences and Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds, United Kingdom
- Department of Laboratory and Blood Bank, Al Mikhwah General Hospital, Al Mikhwah, Saudi Arabia
| | - Joseph C Ward
- School of Molecular and Cellular Biology, Faculty of Biological Sciences and Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds, United Kingdom
| | - Robert A S Ariëns
- Discovery and Translational Science Department, Leeds Institute of Cardiovascular and Metabolic Medicine, University of Leeds, Leeds, United Kingdom
| | - Mark Harris
- School of Molecular and Cellular Biology, Faculty of Biological Sciences and Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds, United Kingdom
| | - Nicola J Stonehouse
- School of Molecular and Cellular Biology, Faculty of Biological Sciences and Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds, United Kingdom
| | - Morgan R Herod
- School of Molecular and Cellular Biology, Faculty of Biological Sciences and Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds, United Kingdom
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9
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Oechslin N, Ankavay M, Moradpour D, Gouttenoire J. Expanding the Hepatitis E Virus Toolbox: Selectable Replicons and Recombinant Reporter Genomes. Viruses 2023; 15:v15040869. [PMID: 37112849 PMCID: PMC10147066 DOI: 10.3390/v15040869] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2023] [Revised: 03/27/2023] [Accepted: 03/28/2023] [Indexed: 03/31/2023] Open
Abstract
Hepatitis E virus (HEV) has received relatively little attention for decades although it is now considered as one of the most frequent causes of acute hepatitis worldwide. Our knowledge of this enterically-transmitted, positive-strand RNA virus and its life cycle remains scarce but research on HEV has gained momentum more recently. Indeed, advances in the molecular virology of hepatitis E, including the establishment of subgenomic replicons and infectious molecular clones, now allow study of the entire viral life cycle and to explore host factors required for productive infection. Here, we provide an overview on currently available systems, with an emphasis on selectable replicons and recombinant reporter genomes. Furthermore, we discuss the challenges in developing new systems which should enable to further investigate this widely distributed and important pathogen.
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10
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Wang Y, Zhao C, Qi Y, Geng Y. Hepatitis E Virus. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2023; 1417:1-13. [PMID: 37223855 DOI: 10.1007/978-981-99-1304-6_1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Since the sequence of hepatitis E virus (HEV) was determined from a patient with enterically transmitted non-A, non-B hepatitis in 1989, similar sequences have been isolated from many different animals, including pigs, wild boars, deer, rabbits, bats, rats, chicken, and trout. All of these sequences have the same genomic organization, which contains open reading frames (ORFs) 1, 2, and 3, although their genomic sequences are variable. Some have proposed that they be classified as new family, Hepeviridae, which would be further divided into different genera and species according to their sequence variability. The size of these virus particles generally ranged from 27 to 34 nm. However, HEV virions produced in cell culture differ in structure from the viruses found in feces. Those from cell culture have a lipid envelope and either lack or have a little ORF3, whereas the viruses isolated from feces lack a lipid envelope but have ORF3 on their surfaces. Surprisingly, most of the secreted ORF2 proteins from both these sources are not associated with HEV RNA.
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Affiliation(s)
- Youchun Wang
- Institute of Medical Biology, Chinese Academy of Medical Science & Peking Union Medical College, Kunming, China.
| | - Chenyan Zhao
- Division of HIV/AIDS and Sex-Transmitted Virus Vaccines, National Institutes for Food and Drug Control, Beijing, China
| | - Ying Qi
- Division of HIV/AIDS and Sex-Transmitted Virus Vaccines, National Institutes for Food and Drug Control, Beijing, China
| | - Yansheng Geng
- Key Laboratory of Public Health Safety of Hebei Province, School of Public Health, Hebei University, Baoding, China
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11
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Zhou Y, Zhao C, Tian Y, Xu N, Wang Y. Characteristics and Functions of HEV Proteins. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2023; 1417:15-32. [PMID: 37223856 DOI: 10.1007/978-981-99-1304-6_2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Hepatitis E virus (HEV) is a non-enveloped virus containing a single-stranded, positive-sense RNA genome of 7.2 kb, which consists of a 5' non-coding region, three open reading frames (ORFs), and a 3' non-coding region. ORF1 is diverse between genotypes and encodes the nonstructural proteins, which include the enzymes needed for virus replication. In addition to its role in virus replication, the function of ORF1 is relevant to viral adaption in culture and may also relate to virus infection and HEV pathogenicity. ORF2 protein is the capsid protein, which is about 660 amino acids in length. It not only protects the integrity of the viral genome, but is also involved in many important physiological activities, such as virus assembly, infection, host interaction, and innate immune response. The main immune epitopes, especially neutralizing epitopes, are located on ORF2 protein, which is a candidate antigen for vaccine development. ORF3 protein is a phosphoprotein of 113 or 114 amino acids with a molecular weight of 13 kDa with multiple functions that can also induce strong immune reactivity. A novel ORF4 has been identified only in genotype 1 HEV and its translation promotes viral replication.
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Affiliation(s)
- Yan Zhou
- RegCMC, Great Regulatory Affairs, Sanofi (China) Investment Co., Ltd, Beijing, China
| | - Chenyan Zhao
- Division of HIV/AIDS and Sex-Transmitted Virus Vaccines, National Institutes for Food and Drug Control, Beijing, China
| | - Yabin Tian
- Division II of In Vitro Diagnostics for Infectious Diseases, National Institutes for Food and Drug Control, Beijing, China
| | - Nan Xu
- Division of HIV/AIDS and Sex-Transmitted Virus Vaccines, National Institutes for Food and Drug Control, Beijing, China
| | - Youchun Wang
- Institute of Medical Biology, Chinese Academy of Medical Science & Peking Union Medical College, Kunming, China.
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12
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Praditya DF, Klöhn M, Brüggemann Y, Brown LE, Porco JA, Zhang W, Kinast V, Kirschning A, Vondran FWR, Todt D, Steinmann E. Identification of structurally re-engineered rocaglates as inhibitors against hepatitis E virus replication. Antiviral Res 2022; 204:105359. [PMID: 35728703 PMCID: PMC9731315 DOI: 10.1016/j.antiviral.2022.105359] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2022] [Revised: 05/16/2022] [Accepted: 06/06/2022] [Indexed: 11/19/2022]
Abstract
Hepatitis E virus (HEV) infections are a leading cause of acute viral hepatitis in humans and pose a considerable threat to public health. Current standard of care treatment is limited to the off-label use of nucleoside-analog ribavirin (RBV) and PEGylated interferon-α, both of which are associated with significant side effects and provide limited efficacy. In the past few years, a promising natural product compound class of eukaryotic initiation factor 4A (eIF4A) inhibitors (translation initiation inhibitors), called rocaglates, were identified as antiviral agents against RNA virus infections. In the present study, we evaluated a total of 205 synthetic rocaglate derivatives from the BU-CMD compound library for their antiviral properties against HEV. At least eleven compounds showed inhibitory activities against the HEV genotype 3 (HEV-3) subgenomic replicon below 30 nM (EC50 value) as determined by Gaussia luciferase assay. Three amidino-rocaglates (ADRs) (CMLD012073, CMLD012118, and CMLD012612) possessed antiviral activity against HEV with EC50 values between 1 and 9 nM. In addition, these three selected compounds inhibited subgenomic replicons of different genotypes (HEV-1 [Sar55], wild boar HEV-3 [83-2] and human HEV-3 [p6]) in a dose-dependent manner and at low nanomolar concentrations. Furthermore, tested ADRs tend to be better tolerated in primary hepatocytes than hepatoma cancer cell lines and combination treatment of CMLD012118 with RBV and interferon-α (IFN-α) showed that CMLD012118 acts additive to RBV and IFN-α treatment. In conclusion, our results indicate that ADRs, especially CMLD012073, CMLD012118, and CMLD012612 may prove to be potential therapeutic candidates for the treatment of HEV infections and may contribute to the discovery of pan-genotypic inhibitors in the future.
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Affiliation(s)
- Dimas F Praditya
- Department of Molecular and Medical Virology, Ruhr-University Bochum, Bochum, Germany; Research Center for Vaccine and Drugs, The National Research and Innovation Agency, Cibinong, Indonesia.
| | - Mara Klöhn
- Department of Molecular and Medical Virology, Ruhr-University Bochum, Bochum, Germany.
| | - Yannick Brüggemann
- Department of Molecular and Medical Virology, Ruhr-University Bochum, Bochum, Germany.
| | - Lauren E Brown
- Department of Chemistry, Boston University, Boston, MA, 02215, USA; Center for Molecular Discovery (BU-CMD), Boston University, Boston, MA, USA.
| | - John A Porco
- Department of Chemistry, Boston University, Boston, MA, 02215, USA; Center for Molecular Discovery (BU-CMD), Boston University, Boston, MA, USA.
| | - Wenhan Zhang
- Department of Chemistry, Boston University, Boston, MA, 02215, USA; Center for Molecular Discovery (BU-CMD), Boston University, Boston, MA, USA.
| | - Volker Kinast
- Department of Molecular and Medical Virology, Ruhr-University Bochum, Bochum, Germany; Department of Medical Microbiology and Virology, Carl von Ossietzky University Oldenburg, Oldenburg, Germany.
| | - Andreas Kirschning
- Institute of Organic Chemistry, Leibniz University Hannover, Schneiderberg 1B, 30167, Hannover, Germany.
| | - Florian W R Vondran
- ReMediES, Department of General, Visceral and Transplantation Surgery, Hannover Medical School, Hannover, Germany; German Centre for Infection Research (DZIF), Partner Site Hannover-Braunschweig, Hannover, Germany.
| | - Daniel Todt
- Department of Molecular and Medical Virology, Ruhr-University Bochum, Bochum, Germany; European Virus Bioinformatics Center (EVBC), 07743, Jena, Germany.
| | - Eike Steinmann
- Department of Molecular and Medical Virology, Ruhr-University Bochum, Bochum, Germany; German Centre for Infection Research (DZIF), External Partner Site, Bochum, Germany.
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13
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Viral Interference of Hepatitis C and E Virus Replication in Novel Experimental Co-Infection Systems. Cells 2022; 11:cells11060927. [PMID: 35326378 PMCID: PMC8946046 DOI: 10.3390/cells11060927] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2022] [Revised: 03/04/2022] [Accepted: 03/04/2022] [Indexed: 12/04/2022] Open
Abstract
Background: Hepatitis C virus (HCV) constitutes a global health problem, while hepatitis E virus (HEV) is the major cause of acute viral hepatitis globally. HCV/HEV co-infections have been poorly characterized, as they are hampered by the lack of robust HEV cell culture systems. This study developed experimental models to study HCV/HEV co-infections and investigate viral interference in cells and humanized mice. Methods: We used state-of-the art human hepatocytes tissue culture models to assess HEV and HCV replication in co- or super-transfection settings. Findings were confirmed by co- and super-infection experiments in human hepatocytes and in vivo in human liver chimeric mice. Results: HEV was inhibited by concurrent HCV replication in human hepatocytes. This exclusion phenotype was linked to the protease activity of HCV. These findings were corroborated by the fact that in HEV on HCV super-infected mice, HEV viral loads were reduced in individual mice. Similarly, HCV on HEV super-infected mice showed reduced HCV viral loads. Conclusion: Direct interference of both viruses with HCV NS3/4A as the determinant was observed. In vivo, we detected reduced replication of both viruses after super-infection in individual mice. These findings provide new insights into the pathogenesis of HCV-HEV co-infections and should contribute to its clinical management in the future.
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14
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Metzger K, Bentaleb C, Hervouet K, Alexandre V, Montpellier C, Saliou JM, Ferrié M, Camuzet C, Rouillé Y, Lecoeur C, Dubuisson J, Cocquerel L, Aliouat-Denis CM. Processing and Subcellular Localization of the Hepatitis E Virus Replicase: Identification of Candidate Viral Factories. Front Microbiol 2022; 13:828636. [PMID: 35283856 PMCID: PMC8908324 DOI: 10.3389/fmicb.2022.828636] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2021] [Accepted: 02/01/2022] [Indexed: 01/26/2023] Open
Abstract
Hepatitis E virus (HEV) is the major cause of acute hepatitis worldwide. HEV is a positive-sense RNA virus expressing three open reading frames (ORFs). ORF1 encodes the ORF1 non–structural polyprotein, the viral replicase which transcribes the full-length genome and a subgenomic RNA that encodes the structural ORF2 and ORF3 proteins. The present study is focused on the replication step with the aim to determine whether the ORF1 polyprotein is processed during the HEV lifecycle and to identify where the replication takes place inside the host cell. As no commercial antibody recognizes ORF1 in HEV-replicating cells, we aimed at inserting epitope tags within the ORF1 protein without impacting the virus replication efficacy. Two insertion sites located in the hypervariable region were thus selected to tolerate the V5 epitope while preserving HEV replication efficacy. Once integrated into the infectious full-length Kernow C-1 p6 strain, the V5 epitopes did neither impact the replication of genomic nor the production of subgenomic RNA. Also, the V5-tagged viral particles remained as infectious as the wildtype particles to Huh-7.5 cells. Next, the expression pattern of the V5-tagged ORF1 was compared in heterologous expression and replicative HEV systems. A high molecular weight protein (180 kDa) that was expressed in all three systems and that likely corresponds to the unprocessed form of ORF1 was detected up to 25 days after electroporation in the p6 cell culture system. Additionally, less abundant products of lower molecular weights were detected in both in cytoplasmic and nuclear compartments. Concurrently, the V5-tagged ORF1 was localized by confocal microscopy inside the cell nucleus but also as compact perinuclear substructures in which ORF2 and ORF3 proteins were detected. Importantly, using in situ hybridization (RNAScope ®), positive and negative-strand HEV RNAs were localized in the perinuclear substructures of HEV-producing cells. Finally, by simultaneous detection of HEV genomic RNAs and viral proteins in these substructures, we identified candidate HEV factories.
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Affiliation(s)
- Karoline Metzger
- CNRS, INSERM, CHU Lille, Institut Pasteur de Lille, U1019 – UMR 9017 – Center for Infection and Immunity of Lille (CIIL), Université de Lille, Lille, France
| | - Cyrine Bentaleb
- CNRS, INSERM, CHU Lille, Institut Pasteur de Lille, U1019 – UMR 9017 – Center for Infection and Immunity of Lille (CIIL), Université de Lille, Lille, France
| | - Kévin Hervouet
- CNRS, INSERM, CHU Lille, Institut Pasteur de Lille, U1019 – UMR 9017 – Center for Infection and Immunity of Lille (CIIL), Université de Lille, Lille, France
| | - Virginie Alexandre
- CNRS, INSERM, CHU Lille, Institut Pasteur de Lille, U1019 – UMR 9017 – Center for Infection and Immunity of Lille (CIIL), Université de Lille, Lille, France
| | - Claire Montpellier
- CNRS, INSERM, CHU Lille, Institut Pasteur de Lille, U1019 – UMR 9017 – Center for Infection and Immunity of Lille (CIIL), Université de Lille, Lille, France
| | - Jean-Michel Saliou
- CNRS, Inserm, CHU Lille, Institut Pasteur de Lille, UMR2014 – US41 – Plateformes Lilloises de Biologie and Santé (PLBS), Université de Lille, Lille, France
| | - Martin Ferrié
- CNRS, INSERM, CHU Lille, Institut Pasteur de Lille, U1019 – UMR 9017 – Center for Infection and Immunity of Lille (CIIL), Université de Lille, Lille, France
| | - Charline Camuzet
- CNRS, INSERM, CHU Lille, Institut Pasteur de Lille, U1019 – UMR 9017 – Center for Infection and Immunity of Lille (CIIL), Université de Lille, Lille, France
| | - Yves Rouillé
- CNRS, INSERM, CHU Lille, Institut Pasteur de Lille, U1019 – UMR 9017 – Center for Infection and Immunity of Lille (CIIL), Université de Lille, Lille, France
| | - Cécile Lecoeur
- CNRS, INSERM, CHU Lille, Institut Pasteur de Lille, U1019 – UMR 9017 – Center for Infection and Immunity of Lille (CIIL), Université de Lille, Lille, France
| | - Jean Dubuisson
- CNRS, INSERM, CHU Lille, Institut Pasteur de Lille, U1019 – UMR 9017 – Center for Infection and Immunity of Lille (CIIL), Université de Lille, Lille, France
| | - Laurence Cocquerel
- CNRS, INSERM, CHU Lille, Institut Pasteur de Lille, U1019 – UMR 9017 – Center for Infection and Immunity of Lille (CIIL), Université de Lille, Lille, France
| | - Cécile-Marie Aliouat-Denis
- CNRS, INSERM, CHU Lille, Institut Pasteur de Lille, U1019 – UMR 9017 – Center for Infection and Immunity of Lille (CIIL), Université de Lille, Lille, France
- *Correspondence: Cécile-Marie Aliouat-Denis,
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Yang Y, Sun Z, Li H, Tian J, Chen M, Liu T. Preparation and Immune Effect of HEV ORF2 P206@PLGA Nanoparticles. NANOMATERIALS 2022; 12:nano12040595. [PMID: 35214924 PMCID: PMC8878542 DOI: 10.3390/nano12040595] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/20/2021] [Revised: 01/28/2022] [Accepted: 02/03/2022] [Indexed: 12/12/2022]
Abstract
The hepatitis E virus (HEV) is an important pathogen that threatens global public health. One-third of the world’s population lives in the epidemic area of HEV, causing 20 million infections and 70,000 deaths annually. In China, HEV transmission has changed from human-to-human transmission of HEV1 to zoonotic transmission of HEV4, causing hepatitis outbreaks throughout the country. Protecting vulnerable groups, such as practitioners related to animal husbandry and downstream consumers who are immune deficient or pregnant, from HEV infections is an urgent task. At present, the commercial human vaccine, Hecolin® (HEV 239 vaccine), is licensed for use only in China. HEV 239 vaccine is a human vaccine developed for HEV1. Although it has a cross-protective effect on HEV4, the level of immune protection is still different. To address the transformation of domestic HEV transmission modes, there is an urgent need to develop a new vaccine against zoonotic HEV4. P206@PLGA is a vaccine candidate in which nanomaterials are used to encapsulate viral capsid proteins for the immunization of livestock animals. Our experiments show that P206@PLGA has excellent biocompatibility and safety. In addition, P206@PLGA can effectively induce animals to produce a high titer of antibodies against HEV4, and thus has the potential to become a veterinary vaccine for the prevention of HEV. This approach provides a new concept for HE prevention to reduce the transmission of HEV in farms and protect susceptible populations.
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Affiliation(s)
| | | | | | | | - Mingyong Chen
- Correspondence: (M.C.); (T.L.); Tel.: +86-010-62733398 (T.L.)
| | - Tianlong Liu
- Correspondence: (M.C.); (T.L.); Tel.: +86-010-62733398 (T.L.)
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16
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Gordeychuk I, Kyuregyan K, Kondrashova A, Bayurova E, Gulyaev S, Gulyaeva T, Potemkin I, Karlsen A, Isaeva O, Belyakova A, Lyashenko A, Sorokin A, Chumakov A, Morozov I, Isaguliants M, Ishmukhametov A, Mikhailov M. Immunization with recombinant ORF2 p551 protein protects common marmosets (Callithrix jacchus) against homologous and heterologous hepatitis E virus challenge. Vaccine 2022; 40:89-99. [PMID: 34836660 DOI: 10.1016/j.vaccine.2021.11.042] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2021] [Revised: 10/18/2021] [Accepted: 11/14/2021] [Indexed: 12/23/2022]
Abstract
BACKGROUND Hepatitis E virus (HEV) is a major causative agent of acute hepatitis worldwide, prompting continuous HEV vaccine efforts. Vaccine development is hampered by the lack of convenient animal models susceptible to infection with different HEV genotypes. We produced recombinant open reading frame 2 protein (pORF2; p551) of HEV genotype (GT) 3 and assessed its immunogenicity and protectivity against HEV challenge in common marmosets (Callithrix jacchus, CM). METHODS p551 with consensus sequence corresponding to amino acid residues 110-660 of HEV GT3 pORF2 was expressed in E. coli and purified by affinity chromatography. CMs were immunized intramuscularly with 20 μg of p551 VLPs with alum adjuvant (n = 4) or adjuvant alone (n = 2) at weeks 0, 3, 7 and 19. At week 27, p551-immunized and control animals were challenged with HEV GT1 or GT3 and thereafter longitudinally screened for markers of liver function, anti-HEV IgG and HEV RNA in feces and sera. RESULTS Purified p551 formed VLPs with particle size of 27.71 ± 2.42 nm. Two immunizations with p551 induced anti-HEV IgG mean titer of 1:1810. Immunized CMs challenged with homologous and heterologous HEV genotype did not develop HEV infection during the follow-up. Control CMs infected with both HEV GT1 and GT3 demonstrated signs of HEV infection with virus shedding and elevation of the levels of liver enzymes. High levels of anti-HEV IgG persisted in vaccinated CMs and control CMs that resolved HEV infection, for up to two years post challenge. CONCLUSIONS CMs are shown to be a convenient laboratory animal model susceptible to infection with HEV GT1 and GT3. Immunization with HEV GT3 ORF2/p551 triggers potent anti-HEV antibody response protecting CMs from homologous and heterologous HEV challenge. This advances p551 in VLPs as a prototype vaccine against HEV.
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Affiliation(s)
- Ilya Gordeychuk
- Chumakov Federal Scientific Center for Research and Development of Immune-and-Biological Products of Russian Academy of Sciences, Moscow 108819, Russia; Institute for Translational Medicine and Biotechnology, Sechenov First Moscow State Medical University, Moscow 127994, Russia.
| | - Karen Kyuregyan
- Chumakov Federal Scientific Center for Research and Development of Immune-and-Biological Products of Russian Academy of Sciences, Moscow 108819, Russia; I.I. Mechnikov Research Institute of Vaccines and Sera, Moscow 105064, Russia; Russian Medical Academy of Continuous Professional Education, Moscow 125993, Russia.
| | - Alla Kondrashova
- Chumakov Federal Scientific Center for Research and Development of Immune-and-Biological Products of Russian Academy of Sciences, Moscow 108819, Russia; Institute for Translational Medicine and Biotechnology, Sechenov First Moscow State Medical University, Moscow 127994, Russia
| | - Ekaterina Bayurova
- Chumakov Federal Scientific Center for Research and Development of Immune-and-Biological Products of Russian Academy of Sciences, Moscow 108819, Russia.
| | - Stanislav Gulyaev
- Chumakov Federal Scientific Center for Research and Development of Immune-and-Biological Products of Russian Academy of Sciences, Moscow 108819, Russia.
| | - Tatiana Gulyaeva
- Chumakov Federal Scientific Center for Research and Development of Immune-and-Biological Products of Russian Academy of Sciences, Moscow 108819, Russia.
| | - Ilya Potemkin
- Chumakov Federal Scientific Center for Research and Development of Immune-and-Biological Products of Russian Academy of Sciences, Moscow 108819, Russia; I.I. Mechnikov Research Institute of Vaccines and Sera, Moscow 105064, Russia; Russian Medical Academy of Continuous Professional Education, Moscow 125993, Russia.
| | - Anastasia Karlsen
- Chumakov Federal Scientific Center for Research and Development of Immune-and-Biological Products of Russian Academy of Sciences, Moscow 108819, Russia; I.I. Mechnikov Research Institute of Vaccines and Sera, Moscow 105064, Russia; Russian Medical Academy of Continuous Professional Education, Moscow 125993, Russia; N.F. Gamaleya Federal Research Center for Epidemiology & Microbiology, Moscow 123098, Russia
| | - Olga Isaeva
- I.I. Mechnikov Research Institute of Vaccines and Sera, Moscow 105064, Russia; Russian Medical Academy of Continuous Professional Education, Moscow 125993, Russia.
| | - Alla Belyakova
- Chumakov Federal Scientific Center for Research and Development of Immune-and-Biological Products of Russian Academy of Sciences, Moscow 108819, Russia.
| | - Anna Lyashenko
- Chumakov Federal Scientific Center for Research and Development of Immune-and-Biological Products of Russian Academy of Sciences, Moscow 108819, Russia.
| | - Alexey Sorokin
- Chumakov Federal Scientific Center for Research and Development of Immune-and-Biological Products of Russian Academy of Sciences, Moscow 108819, Russia
| | - Alexey Chumakov
- Chumakov Federal Scientific Center for Research and Development of Immune-and-Biological Products of Russian Academy of Sciences, Moscow 108819, Russia; Institute for Translational Medicine and Biotechnology, Sechenov First Moscow State Medical University, Moscow 127994, Russia
| | - Igor Morozov
- Chumakov Federal Scientific Center for Research and Development of Immune-and-Biological Products of Russian Academy of Sciences, Moscow 108819, Russia.
| | - Maria Isaguliants
- Chumakov Federal Scientific Center for Research and Development of Immune-and-Biological Products of Russian Academy of Sciences, Moscow 108819, Russia; N.F. Gamaleya Federal Research Center for Epidemiology & Microbiology, Moscow 123098, Russia; Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, 17177 Stockholm, Sweden.
| | - Aydar Ishmukhametov
- Chumakov Federal Scientific Center for Research and Development of Immune-and-Biological Products of Russian Academy of Sciences, Moscow 108819, Russia; Institute for Translational Medicine and Biotechnology, Sechenov First Moscow State Medical University, Moscow 127994, Russia.
| | - Mikhail Mikhailov
- I.I. Mechnikov Research Institute of Vaccines and Sera, Moscow 105064, Russia; Russian Medical Academy of Continuous Professional Education, Moscow 125993, Russia.
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The Capsid (ORF2) Protein of Hepatitis E Virus in Feces Is C-Terminally Truncated. Pathogens 2021; 11:pathogens11010024. [PMID: 35055972 PMCID: PMC8779013 DOI: 10.3390/pathogens11010024] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2021] [Revised: 12/21/2021] [Accepted: 12/24/2021] [Indexed: 11/17/2022] Open
Abstract
The hepatitis E virus (HEV) is a causative agent of hepatitis E. HEV virions in circulating blood and culture media are quasi-enveloped, while those in feces are nonenveloped. The capsid (ORF2) protein associated with an enveloped HEV virion is reported to comprise the translation product of leucine 14/methionine 16 to 660 (C-terminal end). However, the nature of the ORF2 protein associated with fecal HEV remains unclear. In the present study, we compared the molecular size of the ORF2 protein among fecal HEV, cell-culture-generated HEV (HEVcc), and detergent-treated protease-digested HEVcc. The ORF2 proteins associated with fecal HEV were C-terminally truncated and showed the same size as those of the detergent-treated protease-digested HEVcc virions (60 kDa), in contrast to those of the HEVcc (68 kDa). The structure prediction of the ORF2 protein (in line with previous studies) demonstrated that the C-terminal region (54 amino acids) of an ORF2 protein is in flux, suggesting that proteases target this region. The nonenveloped nondigested HEV structure prediction indicates that the C-terminal region of the ORF2 protein moves to the surface of the virion and is unnecessary for HEV infection. Our findings clarify the maturation of nonenveloped HEV and will be useful for studies on the HEV lifecycle.
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18
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Cellular Organelles Involved in Hepatitis E Virus Infection. Pathogens 2021; 10:pathogens10091206. [PMID: 34578238 PMCID: PMC8469867 DOI: 10.3390/pathogens10091206] [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: 08/21/2021] [Revised: 09/16/2021] [Accepted: 09/16/2021] [Indexed: 12/24/2022] Open
Abstract
Hepatitis E virus (HEV), a major cause of acute hepatitis worldwide, infects approximately 20 million individuals annually. HEV can infect a wide range of mammalian and avian species, and cause frequent zoonotic spillover, increasingly raising public health concerns. To establish a successful infection, HEV needs to usurp host machineries to accomplish its life cycle from initial attachment to egress. However, relatively little is known about the HEV life cycle, especially the functional role(s) of cellular organelles and their associated proteins at different stages of HEV infection. Here, we summarize current knowledge regarding the relation of HEV with the different cell organelles during HEV infection. Furthermore, we discuss the underlying mechanisms by which HEV infection is precisely regulated in infected cells and the modification of host cell organelles and their associated proteins upon HEV infection.
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19
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Bai H, Kataoka M, Ami Y, Suzaki Y, Takeda N, Muramatsu M, Li TC. Immunogenicity and Antigenicity of Rabbit Hepatitis E Virus-Like Particles Produced by Recombinant Baculoviruses. Viruses 2021; 13:v13081573. [PMID: 34452436 PMCID: PMC8402727 DOI: 10.3390/v13081573] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2021] [Revised: 07/28/2021] [Accepted: 08/06/2021] [Indexed: 12/14/2022] Open
Abstract
Rabbit hepatitis E virus (HEV) is a novel HEV belonging to genotype 3 (HEV-3) in the Orthohepevirus A species of the genus Hepevirus, family Hepeviridae. Rabbit HEV was originally isolated from rabbits and found to cause zoonotic infection. Although rabbit HEV can be successfully grown in culture with several cell lines, including the human carcinoma cell line PLC/PRF/5, it is difficult to obtain the large amounts of viral antigen required for diagnosis and vaccine development. In this study, we expressed N-terminal 13 and 111 aa-truncated rabbit HEV ORF2 proteins using recombinant baculoviruses and obtained two types of virus-like particles (VLPs), RnVLPs and RsVLPs with ~35 and 24 nm diameter, respectively. Anti-rabbit HEV IgG antibodies were induced in high titer by immunizing rabbits with RnVLPs or RsVLPs. The antibody secretion in the serum persisted more than three years. RsVLPs showed stronger antigenic cross-reactivity against HEV-1, HEV-3 and HEV-4 than rat HEV. Moreover, anti-RsVLPs antibodies neutralized not only the cognate virus but also HEV-1, HEV-3 and HEV-4 ex vivo, indicating that rabbit HEV had the same serotype as human HEVs. In contrast, the antibody did not block rat HEV infection, demonstrating that rat HEV belonged to a different serotype. Animal experiments indicated that immunization with either RnVLPs or RsVLPs completely protected the rabbits from challenge by rabbit HEV, suggesting that the VLPs are candidates for rabbit HEV vaccine development.
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Affiliation(s)
- Huimin Bai
- Department of Basic Medicine and Forensic Medicine, Baotou Medical College, Baotou 014060, China;
| | - Michiyo Kataoka
- Department of Pathology, National Institute of Infectious Diseases, Tokyo 208-0011, Japan;
| | - Yasushi Ami
- Management Department of Biosafety, Laboratory Animal, and Pathogen Bank, National Institute of Infectious Diseases, Tokyo 208-0011, Japan; (Y.A.); (Y.S.)
| | - Yuriko Suzaki
- Management Department of Biosafety, Laboratory Animal, and Pathogen Bank, National Institute of Infectious Diseases, Tokyo 208-0011, Japan; (Y.A.); (Y.S.)
| | - Naokazu Takeda
- Research Institute for Microbial Diseases, Osaka University, Osaka 565-0781, Japan;
| | - Masamichi Muramatsu
- Department of Virology II, National Institute of Infectious Diseases, Tokyo 208-0011, Japan;
| | - Tian-Cheng Li
- Department of Virology II, National Institute of Infectious Diseases, Tokyo 208-0011, Japan;
- Correspondence: ; Tel.: +81-42-561-0771; Fax: +81-42-565-4729
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20
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Wang B, Meng XJ. Structural and molecular biology of hepatitis E virus. Comput Struct Biotechnol J 2021; 19:1907-1916. [PMID: 33995894 PMCID: PMC8079827 DOI: 10.1016/j.csbj.2021.03.038] [Citation(s) in RCA: 32] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2021] [Revised: 03/26/2021] [Accepted: 03/29/2021] [Indexed: 02/07/2023] Open
Abstract
Hepatitis E virus (HEV) is one of the most common causes of acute viral hepatitis, mainly transmitted by fecal-oral route but has also been linked to fulminant hepatic failure, chronic hepatitis, and extrahepatic neurological and renal diseases. HEV is an emerging zoonotic pathogen with a broad host range, and strains of HEV from numerous animal species are known to cross species barriers and infect humans. HEV is a single-stranded, positive-sense RNA virus in the family Hepeviridae. The genome typically contains three open reading frames (ORFs): ORF1 encodes a nonstructural polyprotein for virus replication and transcription, ORF2 encodes the capsid protein that elicits neutralizing antibodies, and ORF3, which partially overlaps ORF2, encodes a multifunctional protein involved in virion morphogenesis and pathogenesis. HEV virions are non-enveloped spherical particles in feces but exist as quasi-enveloped particles in circulating blood. Two types of HEV virus-like particles (VLPs), small T = 1 (270 Å) and native virion-sized T = 3 (320-340 Å) have been reported. There exist two distinct forms of capsid protein, the secreted form (ORF2S) inhibits antibody neutralization, whereas the capsid-associated form (ORF2C) self-assembles to VLPs. Four cis-reactive elements (CREs) containing stem-loops from secondary RNA structures have been identified in the non-coding regions and are critical for virus replication. This mini-review discusses the current knowledge and gaps regarding the structural and molecular biology of HEV with emphasis on the virion structure, genomic organization, secondary RNA structures, viral proteins and their functions, and life cycle of HEV.
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Affiliation(s)
- Bo Wang
- Center for Emerging, Zoonotic and Arthropod-borne Pathogens, Department of Biomedical Sciences and Pathobiology, Virginia-Maryland College of Veterinary Medicine, Virginia Polytechnic Institute and State University, Blacksburg, VA, USA
| | - Xiang-Jin Meng
- Center for Emerging, Zoonotic and Arthropod-borne Pathogens, Department of Biomedical Sciences and Pathobiology, Virginia-Maryland College of Veterinary Medicine, Virginia Polytechnic Institute and State University, Blacksburg, VA, USA
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21
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Xu M, Sun L, Wang Y, Gao S, Yang W, Li M. Different mutations at position 562 of the hepatitis E virus capsid proteins exhibit differential effects on viral neutralizing activity. Exp Ther Med 2020; 21:110. [PMID: 33335573 PMCID: PMC7739852 DOI: 10.3892/etm.2020.9542] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2020] [Accepted: 10/16/2020] [Indexed: 11/15/2022] Open
Abstract
The hepatitis E virus (HEV) capsid protein pORF2 comprises three potential N-linked glycosylation sites. One site, N562, is located at the cell attachment and neutralizing antigenic regions. The present study performed detailed analyses of the effects of specific amino acid substitutions at position 562 in the homodimerization, glycosylation, antigenicity, immunogenicity and neutralization activities of HEV pORF2. Recombinant HEV pORF2 glycoprotein E1 (amino acids 439-617) and three mutant variants (N562L, N562C and N562K) were expressed in Pichia pastoris (P. pastoris) and SDS-PAGE, Western blot analysis, tunicamycin assay, double-antibody sandwich ELISA and in vitro PCR-based neutralization assay were performed to characterize the different constructs. All proteins were indicated to be secreted by P. pastoris and formed homodimers. Tunicamycin assay revealed the glycosylated status of the wild-type protein, but the mutants were indicated to be non-glycosylated. All proteins were immunoreactive with a neutralizing monoclonal antibody but were not recognized by the antibody after denaturation into monomers. An in vitro PCR-based neutralization assay using mouse antibodies indicated efficient neutralization against N562L, whereas antibodies against N562C and N562K were revealed to be non-neutralizing. Collectively, the present study indicated that specific amino acid substitutions at position 562 serve crucial roles in the activity of the HEV neutralizing epitope.
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Affiliation(s)
- Mingjie Xu
- Medical Research and Laboratory Diagnostic Center, Jinan Central Hospital Affiliated to Shandong First Medical University and Shandong Academy of Medical Sciences, Jinan, Shandong 250013, P.R. China
| | - Lizhi Sun
- Medical Research and Laboratory Diagnostic Center, Jinan Central Hospital Affiliated to Shandong First Medical University and Shandong Academy of Medical Sciences, Jinan, Shandong 250013, P.R. China
| | - Yan Wang
- Medical Research and Laboratory Diagnostic Center, Jinan Central Hospital Affiliated to Shandong First Medical University and Shandong Academy of Medical Sciences, Jinan, Shandong 250013, P.R. China
| | - Shuchun Gao
- Department of Liver Disease, Jinan Infectious Disease Hospital Affiliated to Shandong University, Jinan, Shandong 250021, P.R. China.,Department of Digestive Disease, Shandong Provincial Hospital Affiliated to Shandong University, Jinan, Shandong 250021, P.R. China
| | - Weihua Yang
- Medical Research and Laboratory Diagnostic Center, Jinan Central Hospital Affiliated to Shandong First Medical University and Shandong Academy of Medical Sciences, Jinan, Shandong 250013, P.R. China
| | - Meng Li
- Medical Research and Laboratory Diagnostic Center, Jinan Central Hospital Affiliated to Shandong First Medical University and Shandong Academy of Medical Sciences, Jinan, Shandong 250013, P.R. China
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22
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Chanmanee T, Ajawatanawong P, Louisirirotchanakul S, Chotiyaputta W, Chainuvati S, Wongprompitak P. Phylogenetic analysis of two new complete genomes of the hepatitis E virus (HEV) genotype 3 from Thailand. Mol Biol Rep 2020; 47:8657-8668. [PMID: 33058031 PMCID: PMC7674359 DOI: 10.1007/s11033-020-05908-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2019] [Accepted: 10/08/2020] [Indexed: 02/06/2023]
Abstract
Hepatitis E virus (HEV) is a causative agent of acute viral hepatitis globally. Evolutionary phylogeny classifies the HEV into eight genotypes that correlate with the viral transmission. Only four genotypes have been proven to be responsible for transmission in humans. However, there has been no report on the genomics and genotyping of HEV in Thailand during the past ten years. Here, we identified the genotype distributions of the Thai isolates of HEV and we sequenced two HEV genomes. We screened for 18 Thai isolates of HEV from Siriraj Hospital in Bangkok, from 2014–2016. The HEV genomes were sequenced from the serum and feces of a patient. The results showed that all Thai isolates of HEV were identified as genotype 3 (HEV-3). The ORF2 and genome phylogenies suggested two subgenotypes, called 3.1 and 3.2. The Thai isolates of HEV were frequently found in the subgenotype 3.1. The genome sequences of the two Thai isolates of HEV from the serum and fecal samples of the same patient showed 91% nucleotide similarity with the HEV genotype 3. Comparisons between the HEV genome and the ORF2 phylogenies illustrated that the ORF2 tree can be used to identify HEV genotypes, but it has less phylogenetic power for the HEV evolution. The two new genome sequences of HEV-3 from Thailand could contribute valuable information to the HEV genome study. (226 words)
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Affiliation(s)
- Tipsuda Chanmanee
- Department of Microbiology, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand
| | - Pravech Ajawatanawong
- Division of Bioinformatics and Data Management for Research, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand
| | - Suda Louisirirotchanakul
- Department of Microbiology, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand
| | - Watcharasak Chotiyaputta
- Division of Gastroenterology, Department of Medicine, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand
| | - Siwaporn Chainuvati
- Division of Gastroenterology, Department of Medicine, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand
| | - Patimaporn Wongprompitak
- Department of Immunology, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand.
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23
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Liao MH, Wu FT, Bai H, Doan YH, Yang JY, Takeda N, Muramatsu M, Li TC. Hepatitis E virus infection in 6-month-old pigs in Taiwan. Sci Rep 2020; 10:16869. [PMID: 33037297 PMCID: PMC7547095 DOI: 10.1038/s41598-020-74034-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2019] [Accepted: 09/18/2020] [Indexed: 11/01/2022] Open
Abstract
Hepatitis E virus (HEV) is the causative agent of acute hepatitis E. Genotype 3 (G3) and 4 (G4) HEV have recently been identified in and isolated from swine as the main HEV genotypes worldwide. However, there is limited information on HEV infection status among pigs in Taiwan, especially pigs in the stage before transportation to the slaughterhouse. To determine the frequency of HEV infection among pigs in Taiwan, we detected and quantified HEV RNA contained in 295 fecal specimens collected from 6-month-old pigs bred in 30 pig farms located in 8 counties. We found that 25.1% (74/295) of the fecal specimens were positive for HEV RNA by a quantitative real-time reverse transcription-polymerase chain reaction, and the copy number ranged from 2.3 × 103 to 2.08 × 107 copies/g. Amplification of a 338 bp sequence in ORF2 was achieved in 16 of 74 HEV RNA-positive samples, and their nucleotide sequences were determined. Two HEV sequences appeared to belong to subtype 3a of G3 and the remaining 14 HEV sequences belonged to subtype 4b of G4 (G4b). The entire genome sequence of two G4b HEVs was obtained by next-generation sequence analyses, and the phylogenetic analyses indicated that unique G4b HEVs were circulating in pig farms in Taiwan. In the present study, we found that both G3 and G4 HEVs were circulating in Taiwanese pig farms and G4b was the predominant subtype. In addition, the relatively high detection frequency of HEV RNA in the 6-month-old pigs indicated that Taiwanese pigs just before transportation to the slaughterhouse are at risk of carrying HEVs, and thus thorough cooking or heating of pork meat or organs is needed before consumption in Taiwan and possibly in other countries as well.
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Affiliation(s)
- Ming-Hui Liao
- Department of Veterinary Medicine, College of Veterinary Medicine, National Pingtung University of Science and Technology, No. 1, Hseuh-Fu Road, Nei Pu, Pingtung, 91201, Taiwan.,Department of Post-Baccalaureate Veterinary Medicine, College of Medical and Health Science, Asia University, No. 500, Liou-Feng Road, Wufeng Dist., Taichung City, 41354, Taiwan
| | - Fang-Tzy Wu
- Center for Research, Diagnostics and Vaccine Development, Taiwan Centers for Disease Control, No.161, Kun-Yang Street, Taipei City, 11561, Taiwan
| | - Huimin Bai
- Department of Basic Medicine and Forensic Medicine, Baotou Medical College, Jianshe Road 31, Baotou, 014060, Inner Mongolia, People's Republic of China
| | - Yen Hai Doan
- Department of Environmental Parasitology, Tokyo Medical and Dental University, M&D Tower 16F, 1-5-45 Yushima, Bunkyo-ku, Tokyo, 113-8519, Japan
| | - Jyh-Yuan Yang
- Center for Research, Diagnostics and Vaccine Development, Taiwan Centers for Disease Control, No.161, Kun-Yang Street, Taipei City, 11561, Taiwan
| | - Naokazu Takeda
- Research Institute for Microbial Diseases, Osaka University, Suita, Osaka, 565-0781, Japan
| | - Masamichi Muramatsu
- Department of Virology II, National Institute of Infectious Diseases, 4-7-1 Gakuen, Musashi-murayama, Tokyo, 208-0011, Japan
| | - Tian-Cheng Li
- Department of Virology II, National Institute of Infectious Diseases, 4-7-1 Gakuen, Musashi-murayama, Tokyo, 208-0011, Japan.
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Abstract
Hepatitis A virus (HAV) and hepatitis E virus (HEV) infections are the main causes for acute hepatitis worldwide. Both viruses had long been considered as nonenveloped viruses. However, recent work has uncovered that both viruses circulate in the bloodstream as membrane-cloaked, "quasi-enveloped" particles that are, surprisingly, infectious and likely the only form mediating virus spread within the host. The discovery of quasi-enveloped HAV and HEV particles has fundamentally changed the traditional view on the life cycle and pathogenesis of these viruses. However, because HAV and HEV are phylogenetically unrelated and their capsid assembly processes are quite distinct, it is not clear whether they use similar or different mechanisms for envelopment and exit. This review provides an overview of the current knowledge about the assembly and exit processes of HAV and HEV and perspectives for future studies.
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Affiliation(s)
- Zongdi Feng
- Center for Vaccines and Immunity, The Abigail Wexner Research Institute at Nationwide Children's Hospital, Columbus, OH, United States; Department of Pediatrics, Ohio State University College of Medicine, Columbus, OH, United States.
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25
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Scholz J, Falkenhagen A, Bock CT, Johne R. Reverse genetics approaches for hepatitis E virus and related viruses. Curr Opin Virol 2020; 44:121-128. [PMID: 32818718 DOI: 10.1016/j.coviro.2020.07.004] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2020] [Revised: 06/05/2020] [Accepted: 07/06/2020] [Indexed: 12/19/2022]
Abstract
The hepatitis E virus (HEV) is the causative agent of acute and chronic hepatitis in humans. Related viruses have been found in several animal species. Reverse genetics systems (RGSs), which enable the generation of infectious virus from cloned cDNA by transfection of cultured cells or intrahepatic injection into laboratory animals, have been developed for HEV genotypes 1, 3, 4, 5 and 7 as well as for avian HEV and rat HEV. However, low virus recovery rates and slow replication in cell cultures are observed for most of the HEV types. Nevertheless, the RGSs enabled the site-directed mutagenesis of single nucleotides, deletion of genome fragments, insertion of sequence tags and a marker gene as well as the generation of chimeric viruses.
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Affiliation(s)
- Johannes Scholz
- Department Biological Safety, German Federal Institute for Risk Assessment, Berlin, Germany
| | - Alexander Falkenhagen
- Department Biological Safety, German Federal Institute for Risk Assessment, Berlin, Germany
| | - Claus-Thomas Bock
- Division of Viral Gastroenteritis and Hepatitis Pathogens and Enteroviruses, Department of Infectious Diseases, Robert Koch Institute, Berlin, Germany
| | - Reimar Johne
- Department Biological Safety, German Federal Institute for Risk Assessment, Berlin, Germany.
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26
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Kumar M, Hooda P, Khanna M, Patel U, Sehgal D. Development of BacMam Induced Hepatitis E Virus Replication Model in Hepatoma Cells to Study the Polyprotein Processing. Front Microbiol 2020; 11:1347. [PMID: 32625196 PMCID: PMC7315041 DOI: 10.3389/fmicb.2020.01347] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2020] [Accepted: 05/26/2020] [Indexed: 01/10/2023] Open
Abstract
The processing of polyprotein(s) to form structural and non-structural components remains an enigma due to the non-existence of an efficient and robust Hepatitis E Virus (HEV) culture system. We used the BacMam approach to construct an HEV replication model in which the HEV genome was cloned in the BacMam vector under the CMV promoter. The recombinant BacMam was used to infect Huh7 cells to transfer the HEV genome. HEV replication was authenticated by the presence of RNAs of both the polarity (+) and (-) and formation of hybrid RNA, a replication intermediate. The presence of genes for Papain-like Cysteine Protease (PCP), methyltransferase (MeT), RNA dependent RNA polymerase (RdRp), and ORF2 was confirmed by PCR amplification. Further, the infectious nature of the culture system was established as evidenced by the cross-infection of uninfected cells using the cell lysate from the infected cells. The HEV replication model was validated by detection of the ORF1 (Open Reading Frame1) encoded proteins, identified by Western blotting and Immunofluorescence by using epitope-specific antibodies against each protein. Consequently, discrete bands of 18, 35, 37, and 56 kDa corresponding to PCP, MeT, RdRp, and ORF2, respectively, were seen. Besides demonstrating the presence of non-structural enzymes of HEV along with ORF2, activity of a key enzyme, HEV-methyltransferase has also been observed. A 20% decrease in the replicative forms of RNA could be seen in presence of 100 μM Ribavirin after 48 h of treatment. The inhibition gradually increased from 0 to 24 to 48 h post-treatment. Summarily, infectious HEV culture system has been established, which could demonstrate the presence of HEV replicative RNA forms, the structural and non-structural proteins and the methyltransferase in its active form. The system may also be used to study the mechanism of action of Ribavirin in inhibiting HEV replication and develop a therapy.
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Affiliation(s)
- Manjeet Kumar
- Virology Laboratory, Department of Life Sciences, Shiv Nadar University, Greater Noida, India
| | - Preeti Hooda
- Virology Laboratory, Department of Life Sciences, Shiv Nadar University, Greater Noida, India
| | - Madhu Khanna
- Virology Lab, Department of Virology, Vallabhbhai Patel Chest Institute, University of Delhi, New Delhi, India
| | - Utkarsh Patel
- Virology Laboratory, Department of Life Sciences, Shiv Nadar University, Greater Noida, India
| | - Deepak Sehgal
- Virology Laboratory, Department of Life Sciences, Shiv Nadar University, Greater Noida, India
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27
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Liu Z, Behloul N, Baha S, Wei W, Tao W, Zhang T, Li W, Shi R, Meng J. Role of the C-terminal cysteines in virus-like particle formation and oligomerization of the hepatitis E virus ORF2 truncated proteins. Virology 2020; 544:1-11. [DOI: 10.1016/j.virol.2020.01.011] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2019] [Revised: 01/26/2020] [Accepted: 01/26/2020] [Indexed: 12/12/2022]
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Abstract
Chronic HEV infections pose a significant clinical problem in immunocompromised individuals. The lack of an efficient cell culture system has severely limited investigation of the HEV life cycle and the development of effective antivirals. Here we report the establishment of a robust HEV cell culture system in human hepatocytes with viral titers up to 106 FFU/mL. These produced intracellular-derived HEVcc particles demonstrated replication to high viral loads in human liver chimeric mice and were able to efficiently infect primary human as well as porcine hepatocytes. This unique infectious cell culture model provides a powerful tool for the analysis of host–virus interactions that should facilitate the discovery of antiviral drugs for this important zoonotic pathogen. Hepatitis E virus (HEV) is the causative agent of hepatitis E in humans and the leading cause for acute viral hepatitis worldwide. The virus is classified as a member of the genus Orthohepevirus A within the Hepeviridae family. Due to the absence of a robust cell culture model for HEV infection, the analysis of the viral life cycle, the development of effective antivirals and a vaccine is severely limited. In this study, we established a protocol based on the HEV genotype 3 p6 (Kernow C-1) and the human hepatoma cell lines HepG2 and HepG2/C3A with different media conditions to produce intracellular HEV cell culture-derived particles (HEVcc) with viral titers between 105 and 106 FFU/mL. Viral titers could be further enhanced by an HEV variant harboring a mutation in the RNA-dependent RNA polymerase. These HEVcc particles were characterized in density gradients and allowed the trans-complementation of subgenomic reporter HEV replicons. In addition, in vitro produced intracellular-derived particles were infectious in liver-humanized mice with high RNA copy numbers detectable in serum and feces. Efficient infection of primary human and swine hepatocytes using the developed protocol could be observed and was inhibited by ribavirin. Finally, RNA sequencing studies of HEV-infected primary human hepatocytes demonstrated a temporally structured transcriptional defense response. In conclusion, this robust cell culture model of HEV infection provides a powerful tool for studying viral–host interactions that should facilitate the discovery of antiviral drugs for this important zoonotic pathogen.
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29
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Recombinant Hepatitis E Viruses Harboring Tags in the ORF1 Protein. J Virol 2019; 93:JVI.00459-19. [PMID: 31315997 PMCID: PMC6744232 DOI: 10.1128/jvi.00459-19] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2019] [Accepted: 07/09/2019] [Indexed: 12/15/2022] Open
Abstract
Hepatitis E virus (HEV) infection is an important cause of acute hepatitis and may lead to chronic infection in immunocompromised patients. Knowledge of the viral life cycle is incomplete due to the limited availability of functional tools. In particular, low levels of expression of the ORF1 protein or limited sensitivity of currently available antibodies or both limit our understanding of the viral replicase. Here, we report the successful establishment of subgenomic HEV replicons and full-length genomes harboring an epitope tag or a functional reporter in the ORF1 protein. These novel tools should allow further characterization of the HEV replication complex and to improve our understanding of the viral life cycle. Hepatitis E virus (HEV) is one of the most common causes of acute hepatitis and jaundice in the world. Current understanding of the molecular virology and pathogenesis of hepatitis E is incomplete, due particularly to the limited availability of functional tools. Here, we report the development of tagged HEV genomes as a novel tool to investigate the viral life cycle. A selectable subgenomic HEV replicon was subjected to random 15-nucleotide sequence insertion using transposon-based technology. Viable insertions in the open reading frame 1 (ORF1) protein were selected in a hepatoblastoma cell line. Functional insertion sites were identified downstream of the methyltransferase domain, in the hypervariable region (HVR), and between the helicase and RNA-dependent RNA polymerase domains. HEV genomes harboring a hemagglutinin (HA) epitope tag or a small luciferase (NanoLuc) in the HVR were found to be fully functional and to allow the production of infectious virus. NanoLuc allowed quantitative monitoring of HEV infection and replication by luciferase assay. The use of HA-tagged replicons and full-length genomes allowed localization of putative sites of HEV RNA replication by the simultaneous detection of viral RNA by fluorescence in situ hybridization and of ORF1 protein by immunofluorescence. Candidate HEV replication complexes were found in cytoplasmic dot-like structures which partially overlapped ORF2 and ORF3 proteins as well as exosomal markers. Hence, tagged HEV genomes yield new insights into the viral life cycle and should allow further investigation of the structure and composition of the viral replication complex. IMPORTANCE Hepatitis E virus (HEV) infection is an important cause of acute hepatitis and may lead to chronic infection in immunocompromised patients. Knowledge of the viral life cycle is incomplete due to the limited availability of functional tools. In particular, low levels of expression of the ORF1 protein or limited sensitivity of currently available antibodies or both limit our understanding of the viral replicase. Here, we report the successful establishment of subgenomic HEV replicons and full-length genomes harboring an epitope tag or a functional reporter in the ORF1 protein. These novel tools should allow further characterization of the HEV replication complex and to improve our understanding of the viral life cycle.
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30
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Shiota T, Li TC, Nishimura Y, Yoshizaki S, Sugiyama R, Shimojima M, Saijo M, Shimizu H, Suzuki R, Wakita T, Muramatsu M, Ishii K. Integrin α3 is involved in non-enveloped hepatitis E virus infection. Virology 2019; 536:119-124. [PMID: 31421623 DOI: 10.1016/j.virol.2019.07.025] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2019] [Revised: 07/29/2019] [Accepted: 07/29/2019] [Indexed: 12/20/2022]
Abstract
Hepatitis E virus (HEV) causes acute and fulminant hepatitis worldwide. Although enveloped (e) and non-enveloped (ne) forms of HEV have been discovered, host factors involved in infection, including receptors, remain to be elucidated. Here, we identified integrin α3 (encoded by ITGA3), a protein that binds and responds to the extracellular matrix, as an essential host factor for HEV infection. Integrin α3 expression was lower in four HEV-non-permissive cell subclones than in an HEV-permissive subclone. ITGA3 knockout cells lost HEV permissibility, suggesting that integrin α3 is critical for HEV infection. Stable expression of integrin α3 in an HEV-non-permissive subclone provided permissibility only to infection by neHEV; expression of integrin α3 lacking the ectodomain did not. Direct interaction between neHEV and the integrin α3 ectodomain was confirmed by co-precipitation using a soluble integrin α3-Fc. These results strongly suggest that integrin α3 is a key molecule for cellular attachment and entry of neHEV.
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Affiliation(s)
- Tomoyuki Shiota
- Department of Virology II, National Institute of Infectious Diseases, Gakuen 4-7-1, Musashi-murayama, Tokyo, 208-0011, Japan
| | - Tian-Cheng Li
- Department of Virology II, National Institute of Infectious Diseases, Gakuen 4-7-1, Musashi-murayama, Tokyo, 208-0011, Japan
| | - Yorihiro Nishimura
- Department of Virology II, National Institute of Infectious Diseases, Gakuen 4-7-1, Musashi-murayama, Tokyo, 208-0011, Japan
| | - Sayaka Yoshizaki
- Department of Virology II, National Institute of Infectious Diseases, Gakuen 4-7-1, Musashi-murayama, Tokyo, 208-0011, Japan
| | - Ryuichi Sugiyama
- Department of Virology II, National Institute of Infectious Diseases, Gakuen 4-7-1, Musashi-murayama, Tokyo, 208-0011, Japan
| | - Masayuki Shimojima
- Department of Virology I, National Institute of Infectious Diseases, Gakuen 4-7-1, Musashi-murayama, Tokyo, 208-0011, Japan
| | - Masayuki Saijo
- Department of Virology I, National Institute of Infectious Diseases, Gakuen 4-7-1, Musashi-murayama, Tokyo, 208-0011, Japan
| | - Hiroyuki Shimizu
- Department of Virology II, National Institute of Infectious Diseases, Gakuen 4-7-1, Musashi-murayama, Tokyo, 208-0011, Japan
| | - Ryosuke Suzuki
- Department of Virology II, National Institute of Infectious Diseases, Gakuen 4-7-1, Musashi-murayama, Tokyo, 208-0011, Japan
| | - Takaji Wakita
- Department of Virology II, National Institute of Infectious Diseases, Gakuen 4-7-1, Musashi-murayama, Tokyo, 208-0011, Japan
| | - Masamichi Muramatsu
- Department of Virology II, National Institute of Infectious Diseases, Gakuen 4-7-1, Musashi-murayama, Tokyo, 208-0011, Japan
| | - Koji Ishii
- Department of Quality Assurance and Radiological Protection, National Institute of Infectious Diseases, Gakuen 4-7-1, Musashi-murayama, Tokyo, 208-0011, Japan.
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31
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Fu RM, Decker CC, Dao Thi VL. Cell Culture Models for Hepatitis E Virus. Viruses 2019; 11:E608. [PMID: 31277308 PMCID: PMC6669563 DOI: 10.3390/v11070608] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2019] [Revised: 06/24/2019] [Accepted: 06/29/2019] [Indexed: 12/14/2022] Open
Abstract
Despite a growing awareness, hepatitis E virus (HEV) remains understudied and investigations have been historically hampered by the absence of efficient cell culture systems. As a result, the pathogenesis of HEV infection and basic steps of the HEV life cycle are poorly understood. Major efforts have recently been made through the development of HEV infectious clones and cellular systems that significantly advanced HEV research. Here, we summarize these systems, discussing their advantages and disadvantages for HEV studies. We further capitalize on the need for HEV-permissive polarized cell models to better recapitulate the entire HEV life cycle and transmission.
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Affiliation(s)
- Rebecca Menhua Fu
- Schaller Research Group at Department of Infectious Diseases and Virology, Heidelberg University Hospital, Cluster of Excellence CellNetworks, 69120 Heidelberg, Germany
- Heidelberg Biosciences International Graduate School, Heidelberg University, 69120 Heidelberg, Germany
| | - Charlotte Caroline Decker
- Schaller Research Group at Department of Infectious Diseases and Virology, Heidelberg University Hospital, Cluster of Excellence CellNetworks, 69120 Heidelberg, Germany
- Heidelberg Biosciences International Graduate School, Heidelberg University, 69120 Heidelberg, Germany
| | - Viet Loan Dao Thi
- Schaller Research Group at Department of Infectious Diseases and Virology, Heidelberg University Hospital, Cluster of Excellence CellNetworks, 69120 Heidelberg, Germany.
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32
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Isolation of Subtype 3c, 3e and 3f-Like Hepatitis E Virus Strains Stably Replicating to High Viral Loads in an Optimized Cell Culture System. Viruses 2019; 11:v11060483. [PMID: 31141895 PMCID: PMC6632007 DOI: 10.3390/v11060483] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2019] [Revised: 05/17/2019] [Accepted: 05/25/2019] [Indexed: 12/18/2022] Open
Abstract
The hepatitis E virus (HEV) is transmitted via the faecal-oral route in developing countries (genotypes 1 and 2) or through contaminated food and blood products worldwide (genotypes 3 and 4). In Europe, HEV subtypes 3c, 3e and 3f are predominant. HEV is the leading cause of acute hepatitis globally and immunocompromised patients are particularly at risk. Because of a lack of cell culture systems efficiently propagating wild-type viruses, research on HEV is mostly based on cell culture-adapted isolates carrying uncommon insertions in the hypervariable region (HVR). While optimizing the cell culture system using the cell culture-adapted HEV strain 47832c, we isolated three wild-type strains derived from clinical specimens representing the predominant spectrum of HEV in Europe. The novel isolates 14-16753 (3c), 14-22707 (3e) and 15-22016 (3f-like) replicate to high viral loads of 108, 109 and 106.5 HEV RNA copies/mL at 14 days post-inoculation, respectively. In addition, they could be kept as persistently infected cell cultures with constant high viral loads (~109 copies/mL) for more than a year. In contrast to the latest isolates 47832c, LBPR-0379 and Kernow-C1, the new isolates do not carry genome insertions in the HVR. Optimization of HEV cell culture identified amphotericin B, distinct salts and fetal calf serum (FCS) as important medium supplements. Overconfluent cell layers increased infectivity and virus production. PLC/PRF/5, HuH-7-Lunet BLR, A549 and HepG2/C3A supported replication with different efficiencies. The novel strains and optimized cell culture system may be useful for studies on the HEV life cycle, inactivation, specific drug and vaccine development.
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Meister TL, Bruening J, Todt D, Steinmann E. Cell culture systems for the study of hepatitis E virus. Antiviral Res 2019; 163:34-49. [PMID: 30653997 DOI: 10.1016/j.antiviral.2019.01.007] [Citation(s) in RCA: 54] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2018] [Revised: 01/08/2019] [Accepted: 01/13/2019] [Indexed: 12/26/2022]
Abstract
Hepatitis E virus (HEV) is the causative agent of hepatitis E in humans and is the leading cause of enterically-transmitted viral hepatitis worldwide. Increasing numbers of HEV infections, together with no available specific anti-HEV treatment, contributes to the pathogen's major health burden. A robust cell culture system is required for virologic studies and the development of new antiviral drugs. Unfortunately, like other hepatitis viruses, HEV is difficult to propagate in conventional cell lines. Many different cell culture systems have been tested using various HEV strains, but viral replication usually progresses very slowly, and infection with low virion counts results in non-productive HEV replication. However, recent progress involving generation of cDNA clones and passaging primary patient isolates in distinct cell lines has improved in vitro HEV propagation. This review describes various approaches to cultivate HEV in cellular and animal models and how these systems are used to study HEV infections and evaluate anti-HEV drug candidates.
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Affiliation(s)
- Toni L Meister
- Ruhr-University Bochum, Faculty of Medicine, Department of Molecular and Medical Virology, Bochum, Germany
| | - Janina Bruening
- Ruhr-University Bochum, Faculty of Medicine, Department of Molecular and Medical Virology, Bochum, Germany
| | - Daniel Todt
- Ruhr-University Bochum, Faculty of Medicine, Department of Molecular and Medical Virology, Bochum, Germany.
| | - Eike Steinmann
- Ruhr-University Bochum, Faculty of Medicine, Department of Molecular and Medical Virology, Bochum, Germany.
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Abstract
Hepatitis E virus (HEV) possesses many of the features of other positive-stranded RNA viruses but also adds HEV-specific nuances, making its virus-host interactions unique. Slow virus replication kinetics and fastidious growth conditions, coupled with the historical lack of an efficient cell culture system to propagate the virus, have left many gaps in our understanding of its structure and replication cycle. Recent advances in culturing selected strains of HEV and resolving the 3D structure of the viral capsid are filling in knowledge gaps, but HEV remains an extremely understudied pathogen. Many steps in the HEV life cycle and many aspects of HEV pathogenesis remain unknown, such as the host and viral factors that determine cross-species infection, the HEV-specific receptor(s) on host cells, what determines HEV chronicity and the ability to replicate in extrahepatic sites, and what regulates processing of the open reading frame 1 (ORF1) nonstructural polyprotein.
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Affiliation(s)
- Scott P Kenney
- Food Animal Health Research Program, The Ohio State University, Wooster, Ohio 44691
| | - Xiang-Jin Meng
- Department of Biomedical Sciences and Pathobiology, Virginia Polytechnic Institute and State University, Blacksburg, Virginia 24061
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Palmitoylation mediates membrane association of hepatitis E virus ORF3 protein and is required for infectious particle secretion. PLoS Pathog 2018; 14:e1007471. [PMID: 30532200 PMCID: PMC6307819 DOI: 10.1371/journal.ppat.1007471] [Citation(s) in RCA: 57] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2018] [Revised: 12/27/2018] [Accepted: 11/16/2018] [Indexed: 02/07/2023] Open
Abstract
Hepatitis E virus (HEV) is a positive-strand RNA virus encoding 3 open reading frames (ORF). HEV ORF3 protein is a small, hitherto poorly characterized protein involved in viral particle secretion and possibly other functions. Here, we show that HEV ORF3 protein forms membrane-associated oligomers. Immunoblot analyses of ORF3 protein expressed in cell-free vs. cellular systems suggested a posttranslational modification. Further analyses revealed that HEV ORF3 protein is palmitoylated at cysteine residues in its N-terminal region, as corroborated by 3H-palmitate labeling, the investigation of cysteine-to-alanine substitution mutants and treatment with the palmitoylation inhibitor 2-bromopalmitate (2-BP). Abrogation of palmitoylation by site-directed mutagenesis or 2-BP treatment altered the subcellular localization of ORF3 protein, reduced the stability of the protein and strongly impaired the secretion of infectious particles. Moreover, selective membrane permeabilization coupled with immunofluorescence microscopy revealed that HEV ORF3 protein is entirely exposed to the cytosolic side of the membrane, allowing to propose a model for its membrane topology and interactions required in the viral life cycle. In conclusion, palmitoylation determines the subcellular localization, membrane topology and function of HEV ORF3 protein in the HEV life cycle. Hepatitis E virus (HEV) infection is believed to be the most common cause of acute hepatitis and jaundice in the world. HEV is a positive-strand RNA virus found as a non-enveloped virion in bile and feces or as a quasi-enveloped virion in blood and in cell culture. The HEV ORF3 protein is involved in viral particle secretion likely through the exosomal pathway. Here, we provide evidence for palmitoylation of ORF3 protein at its N-terminal cysteine-rich domain. Palmitoylation of ORF3 protein determines its subcellular localization and function in particle secretion. In addition, our data indicate a membrane topology where HEV ORF3 protein is entirely exposed to the cytosol, providing important insight into its interactions in the viral life cycle.
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Todt D, Moeller N, Praditya D, Kinast V, Friesland M, Engelmann M, Verhoye L, Sayed IM, Behrendt P, Dao Thi VL, Meuleman P, Steinmann E. The natural compound silvestrol inhibits hepatitis E virus (HEV) replication in vitro and in vivo. Antiviral Res 2018; 157:151-158. [PMID: 30036559 PMCID: PMC7113770 DOI: 10.1016/j.antiviral.2018.07.010] [Citation(s) in RCA: 50] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2017] [Revised: 04/19/2018] [Accepted: 07/17/2018] [Indexed: 02/07/2023]
Abstract
Hepatitis E virus (HEV) is the causative agent of hepatitis E in humans and a member of the genus Orthohepevirus in the family Hepeviridae. HEV infections are the common cause of acute hepatitis but can also take chronic courses. Ribavirin is the treatment of choice for most patients and type I interferon (IFN) has been evaluated in a few infected transplantation patients in vivo. However, no effective and specific treatments against HEV infections are currently available. In this study, we evaluated the natural compound silvestrol, isolated from the plant Aglaia foveolata, and known for its specific inhibition of the DEAD-box RNA helicase eIF4A in state-of-the-art HEV experimental model systems. Silvestrol blocked HEV replication of different subgenomic replicons in a dose-dependent manner at low nanomolar concentrations and acted additive to ribavirin (RBV). In addition, HEV p6-based full length replication and production of infectious particles was reduced in the presence of silvestrol. A pangenotypic effect of the compound was further demonstrated with primary isolates from four different human genotypes in HEV infection experiments of hepatocyte-like cells derived from human embryonic and induced pluripotent stem cells. In vivo, HEV RNA levels rapidly declined in the feces of treated mice while no effect was observed in the vehicle treated control animals. In conclusion, silvestrol could be identified as pangenotypic HEV replication inhibitor in vitro with additive effect to RBV and further demonstrated high potency in vivo. The compound therefore may be considered in future treatment strategies of chronic hepatitis E in immunocompromised patients. The natural compound silvestrol is a potent inhibitor of HEV replication. HEV infection of laboratory and primary isolates could be inhibited by silvestrol. Silvestrol demonstrated high potency in human liver chimeric mice. Targeting translation initiation could be a novel antiviral strategy for the treatment of chronic hepatitis E.
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Affiliation(s)
- Daniel Todt
- Ruhr-University Bochum, Faculty of Medicine, Department of Molecular and Medical Virology, Germany; Institute for Experimental Virology, TWINCORE Centre for Experimental and Clinical Infection Research, a Joint Venture Between the Medical School Hannover (MHH) and the Helmholtz Centre for Infection Research (HZI), Feodor-Lynen-Str. 7, 30625, Hannover, Germany
| | - Nora Moeller
- Institute for Experimental Virology, TWINCORE Centre for Experimental and Clinical Infection Research, a Joint Venture Between the Medical School Hannover (MHH) and the Helmholtz Centre for Infection Research (HZI), Feodor-Lynen-Str. 7, 30625, Hannover, Germany
| | - Dimas Praditya
- Institute for Experimental Virology, TWINCORE Centre for Experimental and Clinical Infection Research, a Joint Venture Between the Medical School Hannover (MHH) and the Helmholtz Centre for Infection Research (HZI), Feodor-Lynen-Str. 7, 30625, Hannover, Germany
| | - Volker Kinast
- Institute for Experimental Virology, TWINCORE Centre for Experimental and Clinical Infection Research, a Joint Venture Between the Medical School Hannover (MHH) and the Helmholtz Centre for Infection Research (HZI), Feodor-Lynen-Str. 7, 30625, Hannover, Germany
| | - Martina Friesland
- Institute for Experimental Virology, TWINCORE Centre for Experimental and Clinical Infection Research, a Joint Venture Between the Medical School Hannover (MHH) and the Helmholtz Centre for Infection Research (HZI), Feodor-Lynen-Str. 7, 30625, Hannover, Germany
| | - Michael Engelmann
- Institute for Experimental Virology, TWINCORE Centre for Experimental and Clinical Infection Research, a Joint Venture Between the Medical School Hannover (MHH) and the Helmholtz Centre for Infection Research (HZI), Feodor-Lynen-Str. 7, 30625, Hannover, Germany
| | - Lieven Verhoye
- Laboratory of Liver Infectious Diseases, Department of Clinical Chemistry, Microbiology and Immunology, Center for Vaccinology, Ghent University, Ghent, Belgium
| | - Ibrahim M Sayed
- Laboratory of Liver Infectious Diseases, Department of Clinical Chemistry, Microbiology and Immunology, Center for Vaccinology, Ghent University, Ghent, Belgium; Microbiology and Immunology Department, Faculty of Medicine, Assuit University, Assuit, Egypt
| | - Patrick Behrendt
- Institute for Experimental Virology, TWINCORE Centre for Experimental and Clinical Infection Research, a Joint Venture Between the Medical School Hannover (MHH) and the Helmholtz Centre for Infection Research (HZI), Feodor-Lynen-Str. 7, 30625, Hannover, Germany; Department of Gastroenterology, Hepatology and Endocrinology, Hannover Medical School, Germany
| | - Viet Loan Dao Thi
- Department of Virology, University Hospital, Heidelberg, Germany; Laboratory of Virology and Infectious Disease, The Rockefeller University, New York, NY, USA
| | - Philip Meuleman
- Laboratory of Liver Infectious Diseases, Department of Clinical Chemistry, Microbiology and Immunology, Center for Vaccinology, Ghent University, Ghent, Belgium
| | - Eike Steinmann
- Ruhr-University Bochum, Faculty of Medicine, Department of Molecular and Medical Virology, Germany; Institute for Experimental Virology, TWINCORE Centre for Experimental and Clinical Infection Research, a Joint Venture Between the Medical School Hannover (MHH) and the Helmholtz Centre for Infection Research (HZI), Feodor-Lynen-Str. 7, 30625, Hannover, Germany.
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van Tong H, Hoan NX, Wang B, Wedemeyer H, Bock CT, Velavan TP. Hepatitis E Virus Mutations: Functional and Clinical Relevance. EBioMedicine 2016; 11:31-42. [PMID: 27528267 PMCID: PMC5049923 DOI: 10.1016/j.ebiom.2016.07.039] [Citation(s) in RCA: 48] [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: 07/25/2016] [Accepted: 07/29/2016] [Indexed: 02/07/2023] Open
Abstract
Hepatitis E virus (HEV) infection is a major cause of acute hepatitis and affects more than 20 million individuals, with three million symptomatic cases and 56,000 recognized HEV-related deaths worldwide. HEV is endemic in developing countries and is gaining importance in developed countries, due to increased number of autochthone cases. Although HEV replication is controlled by the host immune system, viral factors (especially specific viral genotypes and mutants) can modulate HEV replication, infection and pathogenesis. Limited knowledge exists on the contribution of HEV genome variants towards pathogenesis, susceptibility and to therapeutic response. Nonsynonymous substitutions can modulate viral proteins structurally and thus dysregulate virus-host interactions. This review aims to compile knowledge and discuss recent advances on the casual role of HEV heterogeneity and its variants on viral morphogenesis, pathogenesis, clinical outcome and antiviral resistance. HEV causes acute hepatitis and recently comes into focus because of persistent infection in immunocompromised patients. HEV variability can be associated with clinical pathogenesis and transmission dynamics. Mutations in the HEV genome can influence HEV physiology and virus-host interaction. HEV mutations and variability are likely associated with fulminant hepatic failure and chronic hepatitis E. The Y1320H and G1634R/K mutations in the RdRp domain contribute to antiviral resistance through enhancing HEV replication.
We searched MEDLINE database and PubMed for articles from 1980 through June 30, 2016. Search terms used in various combinations were “hepatitis E”, “hepatitis E virus”, “hepatitis E virus infection”, “hepatitis E virus mutation”, “HEV variability”, “HEV genotype”, “HEV drug resistance”, “HEV replication” and “ribavirin”. Articles resulting from these searches and relevant references cited in those articles were selected based on their related topics and were reviewed. Abstracts and reports from meetings were also included. Articles published in English were included.
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Affiliation(s)
- Hoang van Tong
- Institute of Tropical Medicine, University of Tübingen, Tübingen, Germany.
| | - Nghiem Xuan Hoan
- Institute of Tropical Medicine, University of Tübingen, Tübingen, Germany
| | - Bo Wang
- Department of Infectious Diseases, Robert Koch Institute, Berlin, Germany
| | - Heiner Wedemeyer
- Department of Gastroenterology, Hepatology and Endocrinology, Hannover Medical School, Hannover, Germany
| | - C-Thomas Bock
- Department of Infectious Diseases, Robert Koch Institute, Berlin, Germany.
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Pérez-Gracia MT, Suay-García B, García M, Mateos-Lindemann ML. Hepatitis E: latest developments in knowledge. Future Microbiol 2016; 11:789-808. [DOI: 10.2217/fmb-2016-0012] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Hepatitis E, caused by Hepatitis E virus (HEV), is a highly prevalent disease in developing countries. In developed nations, autochthonous HEV infections seem to be an emergent disease. Its clinical manifestations and epidemiology are well known for endemic countries. It has been confirmed that hepatitis E is a zoonosis and that parenteral transmission can also occur. The molecular mechanisms of HEV replication are not fully understood, mostly because there are no efficient cell culture systems. HEV can cause chronic hepatitis in organ transplant recipients and immunocompetent patients. Cases with fulminant hepatitis and other extrahepatic manifestations have also been reported. The diagnosis is based on serological studies and detection of HEV RNA in blood and feces. Treatment with ribavirin and/or pegylated-IFN-α have proven to be successful in some cases. The recently approved/marketed vaccine is a good option in order to prevent this infection.
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Affiliation(s)
- M Teresa Pérez-Gracia
- Área de Microbiología, Departamento de Farmacia, Instituto de Ciencias Biomédicas, Facultad de Ciencias de la Salud, Universidad CEU Cardenal Herrera, Avenida Seminario s/n 46113, Moncada, Valencia, Spain
| | - Beatriz Suay-García
- Área de Microbiología, Departamento de Farmacia, Instituto de Ciencias Biomédicas, Facultad de Ciencias de la Salud, Universidad CEU Cardenal Herrera, Avenida Seminario s/n 46113, Moncada, Valencia, Spain
| | - Mario García
- Área de Microbiología, Departamento de Farmacia, Instituto de Ciencias Biomédicas, Facultad de Ciencias de la Salud, Universidad CEU Cardenal Herrera, Avenida Seminario s/n 46113, Moncada, Valencia, Spain
| | - M Luisa Mateos-Lindemann
- Unidad de Virología, Servicio de Microbiología, Hospital Universitario Ramón y Cajal, Ctra. Colmenar Km 9,1, Madrid 28034, Spain
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Zhou Y, Zhao C, Tian Y, Xu N, Wang Y. Characteristics and Functions of HEV Proteins. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2016; 948:17-38. [PMID: 27738977 DOI: 10.1007/978-94-024-0942-0_2] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Hepatitis E virus (HEV) is a non-enveloped virus containing a single-stranded, positive-sense RNA genome of 7.2 kb, which consists of a 5' noncoding region, three open reading frames (ORFs), and a 3' noncoding region. ORF1 is diverse between genotypes and encodes the nonstructural proteins, which include the enzymes needed for virus replication. In addition to its role in virus replication, the function of ORF1 is relevant to viral adaption in cultured cells and may also relate to virus infection and HEV pathogenicity. ORF2 protein is the capsid protein, which is about 660 amino acids in length. It not only protects the integrity of the viral genome but is also involved in many important physiological activities, such as virus assembly, infection, and host interaction. The main immune epitopes, especially neutralizing epitopes, are located on ORF2 protein, which is a candidate antigen for vaccine development. ORF3 protein is a phosphoprotein of 113 or 114 amino acids with a molecular weight of 13 kDa with multiple functions that can also induce strong immune reactivity.
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Affiliation(s)
- Yan Zhou
- Division of Drug and Cosmetics Inspection, Center for Food and Drug Inspection, China Food and Drug Administration, No.11 Fa Hua Nan Li, Dongcheng District, Beijing, 100061, China
| | - Chenyan Zhao
- Division of HIV/AIDS and Sex-transmitted Virus Vaccines, National Institutes for Food and Drug Control, No. 2 Tiantanxili, Dongcheng District, Beijing, 100050, China
| | - Yabin Tian
- Division of Diagnosis, National Institutes for Food and Drug Control, No. 2 Tiantanxili, Dongcheng District, Beijing, 100050, China
| | - Nan Xu
- Division of HIV/AIDS and Sex-transmitted Virus Vaccines, National Institutes for Food and Drug Control, No. 2 Tiantanxili, Dongcheng District, Beijing, 100050, China
| | - Youchun Wang
- Division of HIV/AIDS and Sex-transmitted Virus Vaccines, National Institutes for Food and Drug Control, No. 2 Tiantanxili, Dongcheng District, Beijing, 100050, China.
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Xu M, Behloul N, Wen J, Zhang J, Meng J. Role of asparagine at position 562 in dimerization and immunogenicity of the hepatitis E virus capsid protein. INFECTION GENETICS AND EVOLUTION 2015; 37:99-107. [PMID: 26584510 DOI: 10.1016/j.meegid.2015.11.006] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/21/2015] [Revised: 10/22/2015] [Accepted: 11/07/2015] [Indexed: 12/11/2022]
Abstract
The hepatitis E virus (HEV) capsid protein, pORF2, contains 2 potential N-glycosylation sites, N137 and N310, located in the S domain, and one site, N562, in the P domain. The last domain located at positions 454-606 aa forms a protruding spike from the shell, with N562 being located in the apical center of the spike, which is also a cell-attachment region and neutralizing antigenic site. Here, we expressed in Pichia pastoris a recombinant polypeptide p179 comprising the region of 439-617 aa of the HEV pORF2 as well as a set of 4 mutant proteins containing substitutions of Q, D, P and Y instead of N at position 562. All proteins were shown to be secreted from yeast. Using SDS-PAGE, Western blot analysis and tunicamycin treatment assay, we showed that the wild-type (wt) protein, p179N562, and 2 mutant variants, p179N562Q and p179N562D, formed homodimers but only the wt protein was shown to be glycosylated. As homodimers, all 3 proteins were immunoreactive with a neutralizing monoclonal antibody (5G5); however, they did not immunoreact with 5G5 after denaturation into monomers. Two other mutant variants, p179N562P and p179N562Y, did not form homodimers but were immunoreactive with the 5G5 antibody. The wt protein was shown to be less immunoreactive with 5G5 than the mutant variants in a double-antibody sandwich ELISA, suggesting a role of glycosylation at N562 in reducing antibody binding. In vitro neutralization experiments showed a more efficient neutralization with mouse antibody against p179N562P and p179N562Y than against the other 3 proteins. These findings indicate that specific substitutions at position 562 have a more measurable effect on the activity of the HEV neutralizing epitope than dimerization or glycosylation of the structural protein. Furthermore, the secretion of monomers fully immunoreactive may call into question the importance of dimerization for an effective presentation of HEV neutralization epitopes.
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Affiliation(s)
- Mingjie Xu
- Department of Microbiology and Immunology, Southeast University, School of Medicine, 87 Dingjiaqiao Road, Nanjing, Jiangsu 210009, China.
| | - Nouredine Behloul
- Department of Microbiology and Immunology, Southeast University, School of Medicine, 87 Dingjiaqiao Road, Nanjing, Jiangsu 210009, China.
| | - Jiyue Wen
- Department of Microbiology and Immunology, Southeast University, School of Medicine, 87 Dingjiaqiao Road, Nanjing, Jiangsu 210009, China.
| | - Jianhua Zhang
- Department of Microbiology and Immunology, Southeast University, School of Medicine, 87 Dingjiaqiao Road, Nanjing, Jiangsu 210009, China.
| | - Jihong Meng
- Department of Microbiology and Immunology, Southeast University, School of Medicine, 87 Dingjiaqiao Road, Nanjing, Jiangsu 210009, China.
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Shiota T, Li TC, Yoshizaki S, Kato T, Wakita T, Ishii K. Establishment of hepatitis E virus infection-permissive and -non-permissive human hepatoma PLC/PRF/5 subclones. Microbiol Immunol 2015; 59:89-94. [PMID: 25495578 DOI: 10.1111/1348-0421.12219] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2014] [Revised: 11/20/2014] [Accepted: 11/28/2014] [Indexed: 12/18/2022]
Abstract
PLC/PRF/5 cells show limited permissiveness, meaning that almost all subclones are permissive; however, some subclones do not exhibit permissiveness for hepatitis E virus (HEV) infection. In this study, the single-cell cloning of PLC/PRF/5 was performed and heterogeneous subclones characterized. Notably, the efficiency of intracellular virus replication did not correlate with the permissiveness for HEV infection. However, as well as binding permissive subclones, virus-like particles bound non-permissive subclones on various levels, suggesting that these subclones have some deficiencies in the attachment and entry steps of infection. Our data would be useful for investigating the HEV life cycle.
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Affiliation(s)
- Tomoyuki Shiota
- Department of Virology II, National Institute of Infectious Diseases, Gakuen 4-7-1, Musashi-murayama, Tokyo, 208-0011, Japan
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Qi Y, Zhang F, Zhang L, Harrison TJ, Huang W, Zhao C, Kong W, Jiang C, Wang Y. Hepatitis E Virus Produced from Cell Culture Has a Lipid Envelope. PLoS One 2015; 10:e0132503. [PMID: 26161670 PMCID: PMC4498737 DOI: 10.1371/journal.pone.0132503] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2015] [Accepted: 06/15/2015] [Indexed: 01/10/2023] Open
Abstract
The absence of a productive cell culture system hampered detailed analysis of the structure and protein composition of the hepatitis E virion. In this study, hepatitis E virus from a robust HEV cell culture system and from the feces of infected monkeys at the peak of virus excretion was purified by ultra-centrifugation. The common feature of the two samples after ultracentrifugation was that the ORF2 protein mainly remained in the top fractions. The ORF2 protein from cell culture system was glycosylated, with an apparent molecular weight of 88 kDa, and was not infectious in PLC/PRF/5 cells. The ORF2 protein in this fraction can bind to and protect HEV RNA from digestion by RNase A. The RNA-ORF2 product has a similar sedimentation coefficient to the virus from feces. The viral RNA in the cell culture supernatant was mainly in the fraction of 1.15 g/cm3 but that from the feces was mainly in the fraction of 1.21 g/cm3. Both were infectious in PLC/PRF/5 cells. And the fraction in the middle of the gradient (1.06 g/cm3) from the cell culture supernatant,but not that from the feces, also has ORF2 protein and HEV RNA but was not infectious in PLC/PRF/5.The infectious RNA-rich fraction from the cell culture contained ORF3 protein and lipid but the corresponding fraction from feces had no lipid and little ORF3 protein. The lipid on the surface of the virus has no effect on its binding to cells but the ORF3 protein interferes with binding. The result suggests that most of the secreted ORF2 protein is not associated with HEV RNA and that hepatitis E virus produced in cell culture differs in structure from the virus found in feces in that it has a lipid envelope.
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Affiliation(s)
- Ying Qi
- National Engineering Laboratory for AIDS Vaccine, Jilin University, Changchun, 130012, China
- Division of HIV/AIDS and Sexually-Transmitted Virus Vaccines, National Institutes for Food and Drug Control, Beijing, 100050, China
| | - Feng Zhang
- Division of HIV/AIDS and Sexually-Transmitted Virus Vaccines, National Institutes for Food and Drug Control, Beijing, 100050, China
| | - Li Zhang
- Division of HIV/AIDS and Sexually-Transmitted Virus Vaccines, National Institutes for Food and Drug Control, Beijing, 100050, China
| | - Tim J. Harrison
- Division of Medicine, University College London Medical School, London, WC1E 6BT, United Kingdom
| | - Weijin Huang
- Division of HIV/AIDS and Sexually-Transmitted Virus Vaccines, National Institutes for Food and Drug Control, Beijing, 100050, China
| | - Chenyan Zhao
- Division of HIV/AIDS and Sexually-Transmitted Virus Vaccines, National Institutes for Food and Drug Control, Beijing, 100050, China
| | - Wei Kong
- National Engineering Laboratory for AIDS Vaccine, Jilin University, Changchun, 130012, China
| | - Chunlai Jiang
- National Engineering Laboratory for AIDS Vaccine, Jilin University, Changchun, 130012, China
| | - Youchun Wang
- Division of HIV/AIDS and Sexually-Transmitted Virus Vaccines, National Institutes for Food and Drug Control, Beijing, 100050, China
- * E-mail:
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Wu J, Si F, Jiang C, Li T, Jin M. Molecular detection of hepatitis E virus in sheep from southern Xinjiang, China. Virus Genes 2015; 50:410-7. [PMID: 25833205 PMCID: PMC4445917 DOI: 10.1007/s11262-015-1194-9] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2014] [Accepted: 03/27/2015] [Indexed: 12/16/2022]
Abstract
Hepatitis E virus (HEV) is a causative agent of infectious hepatitis in animals and humans both in developing and developed countries. Here, we collected 500 sheep sera and 75 raw sheep liver samples from a slaughterhouse in the southern part of the Xinjiang region, China, along with 26 sera of butchers from the same slaughterhouse. All serum samples were tested for anti-HEV antibody by enzyme-linked immunosorbent assay. Both serum and liver samples were evaluated for the presence of HEV RNA by nested polymerase chain reaction targeting partial nucleotide sequences of open reading frame 2 (ORF2). The results indicate that sheep seroprevalence was 35.20 % (176/500) and that four of the 75 (5.3 %) sheep livers showed detectable amounts of HEV RNA. The seroprevalence of the butchers was 57.7 % (15/26). The four amplicons shared 97.8-100 % nucleotide sequence identity and had pairwise sequence identities of 81.6-85.3 %, 84.2-85.3 %, 82.1-85.3 % and 84.7-97.9 % with the corresponding regions of genotypes 1, 2, 3 and 4 of HEV, respectively. A phylogenetic tree was constructed based on alignments of an amplified 186-bp ORF2 sequence and corresponding reference strains. The analysis showed that the four sheep strains detected in our study formed a lineage within a genotype 4 cluster that contains hb-3, bjsw1, T1, swCH189 and swCH25, all of which belong to genotype 4, subtype 4d. The results indicated a high level of seroconversion in sheep and suggested that sheep liver may be a source of foodborne HEV infection in humans.
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Affiliation(s)
- Junyuan Wu
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, 430070, China,
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Li TC, Kataoka M, Takahashi K, Yoshizaki S, Kato T, Ishii K, Takeda N, Mishiro S, Wakita T. Generation of hepatitis E virus-like particles of two new genotypes G5 and G6 and comparison of antigenic properties with those of known genotypes. Vet Microbiol 2015; 178:150-7. [PMID: 25934534 DOI: 10.1016/j.vetmic.2015.04.020] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2015] [Revised: 04/21/2015] [Accepted: 04/22/2015] [Indexed: 12/27/2022]
Abstract
In addition to the four major genotypes (G1 through G4) known for human hepatitis E virus (HEV), two new genotypes (G5 and G6) were suggested, based on unique viral nucleotide sequences derived from wild boars in Japan. It has been unknown whether the virus of these new genotypes can cause hepatitis in humans; neither G5 nor G6 HEV has been found in patients to date. To study the antigenic properties of G5 and G6 HEV, we expressed N-terminus-truncated HEV ORF2 protein by a recombinant baculovirus system, and we obtained virus-like particles (VLPs) for both G5 and G6. The VLPs showed antigenic cross-reactivity against G1, G3 and G4 HEV more strongly than against ferret or rat HEV. Moreover, both anti-G5 and anti-G6 VLPs antibodies could neutralize G3 HEV's ability to infect PLC/PRF/5 cells, suggesting that G5 and G6 HEV have the same serotype as human HEV.
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Affiliation(s)
- Tian-Cheng Li
- Department of Virology II, National Institute of Infectious Diseases, Gakuen 4-7-1, Musashi-murayama, Tokyo 208-0011, Japan.
| | - Michiyo Kataoka
- Department of Pathology, National Institute of Infectious Diseases, Gakuen 4-7-1, Musashi-murayama, Tokyo 208-0011, Japan
| | - Kazuaki Takahashi
- Department of Medical Sciences, Toshiba General Hospital, Shinagawa-Ku, Tokyo 140-8522, Japan
| | - Sayaka Yoshizaki
- Department of Virology II, National Institute of Infectious Diseases, Gakuen 4-7-1, Musashi-murayama, Tokyo 208-0011, Japan
| | - Takanobu Kato
- Department of Virology II, National Institute of Infectious Diseases, Gakuen 4-7-1, Musashi-murayama, Tokyo 208-0011, Japan
| | - Koji Ishii
- Department of Virology II, National Institute of Infectious Diseases, Gakuen 4-7-1, Musashi-murayama, Tokyo 208-0011, Japan
| | - Naokazu Takeda
- Research Institute for Microbial Diseases, Osaka University, Suita, Osaka 565-0781, Japan
| | - Shunji Mishiro
- Department of Medical Sciences, Toshiba General Hospital, Shinagawa-Ku, Tokyo 140-8522, Japan
| | - Takaji Wakita
- Department of Virology II, National Institute of Infectious Diseases, Gakuen 4-7-1, Musashi-murayama, Tokyo 208-0011, Japan
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Panda SK, Varma SP. Hepatitis e: molecular virology and pathogenesis. J Clin Exp Hepatol 2013; 3:114-24. [PMID: 25755485 PMCID: PMC3940135 DOI: 10.1016/j.jceh.2013.05.001] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/30/2013] [Accepted: 05/01/2013] [Indexed: 12/12/2022] Open
Abstract
Hepatitis E virus is a single, positive-sense, capped and poly A tailed RNA virus classified under the family Hepeviridae. Enteric transmission, acute self-limiting hepatitis, frequent epidemic and sporadic occurrence, high mortality in affected pregnants are hallmarks of hepatitis E infection. Lack of an efficient culture system and resulting reductionist approaches for the study of replication and pathogenesis of HEV made it to be a less understood agent. Early studies on animal models, sub-genomic expression of open reading frames (ORF) and infectious cDNA clones have helped in elucidating the genome organization, important stages in HEV replication and pathogenesis. The genome contains three ORF's and three untranslated regions (UTR). The 5' distal ORF, ORF1 is translated by host ribosomes in a cap dependent manner to form the non-structural polyprotein including the viral replicase. HEV replicates via a negative-sense RNA intermediate which helps in the formation of the positive-sense genomic RNA and a single bi-cistronic sub-genomic RNA. The 3' distal ORF's including the major structural protein pORF2 and the multifunctional host interacting protein pORF3 are translated from the sub-genomic RNA. Pathogenesis in HEV infections is not well articulated, and remains a concern due to the many aspects like host dependent and genotype specific variations. Animal HEV, zoonosis, chronicity in immunosuppressed patients, and rapid decompensation in affected chronic liver diseased patients warrants detailed investigation of the underlying pathogenesis. Recent advances about structure, entry, egress and functional characterization of ORF1 domains has furthered our understanding about HEV. This article is an effort to review our present understanding about molecular biology and pathogenesis of HEV.
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Affiliation(s)
- Subrat K. Panda
- Department of Pathology, All India Institute of Medical Sciences, New Delhi 110029, India,Address for correspondence. Subrat K. Panda, JC Bose Fellow, Professor & Head, Department of Pathology, All India Institute of Medical Sciences, New Delhi 110029, India. Tel.: +91 11 26594924 (off.); fax: +91 11 26588663, +91 11 26588641.
| | - Satya P.K. Varma
- Department of Pathology, All India Institute of Medical Sciences, New Delhi 110029, India
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