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Brüggemann Y, Klöhn M, Wedemeyer H, Steinmann E. Hepatitis E virus: from innate sensing to adaptive immune responses. Nat Rev Gastroenterol Hepatol 2024; 21:710-725. [PMID: 39039260 DOI: 10.1038/s41575-024-00950-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 05/29/2024] [Indexed: 07/24/2024]
Abstract
Hepatitis E virus (HEV) infections are a major cause of acute viral hepatitis in humans worldwide. In immunocompetent individuals, the majority of HEV infections remain asymptomatic and lead to spontaneous clearance of the virus, and only a minority of individuals with infection (5-16%) experience symptoms of acute viral hepatitis. However, HEV infections can cause up to 30% mortality in pregnant women, become chronic in immunocompromised patients and cause extrahepatic manifestations. A growing body of evidence suggests that the host immune response to infection with different HEV genotypes is a critical determinant of distinct HEV infection outcomes. In this Review, we summarize key components of the innate and adaptive immune responses to HEV, including the underlying immunological mechanisms of HEV associated with acute and chronic liver failure and interactions between T cell and B cell responses. In addition, we discuss the current status of vaccines against HEV and raise outstanding questions regarding the immune responses induced by HEV and treatment of the disease, highlighting areas for future investigation.
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Affiliation(s)
- Yannick Brüggemann
- Department of Molecular and Medical Virology, Ruhr University Bochum, Bochum, Germany
| | - Mara Klöhn
- Department of Molecular and Medical Virology, Ruhr University Bochum, Bochum, Germany
| | - Heiner Wedemeyer
- Department of Gastroenterology, Hepatology and Endocrinology, Hannover Medical School, Hannover, Germany
- German Center for Infection Research (DZIF), Partner Sites Hannover-Braunschweig, Hannover, Germany
- Cluster of Excellence RESIST (EXC 2155), Hannover Medical School, Hannover, Germany
| | - Eike Steinmann
- Department of Molecular and Medical Virology, Ruhr University Bochum, Bochum, Germany.
- German Center for Infection Research (DZIF), External Partner Site, Bochum, Germany.
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Kanda T, Li TC, Takahashi M, Nagashima S, Primadharsini PP, Kunita S, Sasaki-Tanaka R, Inoue J, Tsuchiya A, Nakamoto S, Abe R, Fujiwara K, Yokosuka O, Suzuki R, Ishii K, Yotsuyanagi H, Okamoto H. Recent advances in hepatitis E virus research and the Japanese clinical practice guidelines for hepatitis E virus infection. Hepatol Res 2024; 54:1-30. [PMID: 38874115 DOI: 10.1111/hepr.14062] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/25/2024] [Revised: 04/22/2024] [Accepted: 05/09/2024] [Indexed: 06/15/2024]
Abstract
Acute hepatitis E was considered rare until reports emerged affirming the existence of hepatitis E virus (HEV) genotypes 3 and 4 infections in Japan in the early 2000s. Extensive studies by Japanese researchers have highlighted the pivotal role of pigs and wild animals, such as wild boars and deer, as reservoirs for HEV, linking them to zoonotic infections in Japan. Currently, when hepatitis occurs subsequent to the consumption of undercooked or grilled pork, wild boar meat, or offal (including pig liver and intestines), HEV infection should be considered. Following the approval of anti-HEV immunoglobulin A antibody as a diagnostic tool for hepatitis E by Japan's Health Insurance System in 2011, the annual number of diagnosed cases of HEV infection has surged. Notably, the occurrence of post-transfusion hepatitis E promoted nationwide screening of blood products for HEV using nucleic acid amplification tests since 2020. Furthermore, chronic hepatitis E has been observed in immunosuppressed individuals. Considering the significance of hepatitis E, heightened preventive measures are essential. The Japan Agency for Medical Research and Development Hepatitis A and E viruses (HAV and HEV) Study Group, which includes special virologists and hepatologists, held a virtual meeting on February 17, 2024. Discussions encompassed pathogenesis, transmission routes, diagnosis, complications, severity factors, and ongoing and prospective vaccination or treatments for hepatitis E. Rigorous assessment of referenced studies culminated in the formulation of recommendations, which are detailed within this review. This comprehensive review presents recent advancements in HEV research and Japanese clinical practice guidelines for HEV infection.
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Affiliation(s)
- Tatsuo Kanda
- Division of Gastroenterology and Hepatology, Department of Medicine, Nihon University School of Medicine, Tokyo, Japan
- Division of Gastroenterology and Hepatology, Uonuma Institute of Community Medicine, Niigata University Medical and Dental Hospital, Minamiuonuma, Japan
- Division of Gastroenterology and Hepatology, Graduate School of Medicine and Dental Sciences, Niigata University, Niigata, Japan
| | - Tian-Cheng Li
- Department of Virology II, National Institute of Infectious Diseases, Tokyo, Japan
| | - Masaharu Takahashi
- Division of Virology, Department of Infection and Immunity, Jichi Medical University School of Medicine, Shimotsuke, Tochigi, Japan
| | - Shigeo Nagashima
- Division of Virology, Department of Infection and Immunity, Jichi Medical University School of Medicine, Shimotsuke, Tochigi, Japan
| | - Putu Prathiwi Primadharsini
- Division of Virology, Department of Infection and Immunity, Jichi Medical University School of Medicine, Shimotsuke, Tochigi, Japan
| | - Satoshi Kunita
- Center for Experimental Medicine, Jichi Medical University School of Medicine, Shimotsuke, Tochigi, Japan
| | - Reina Sasaki-Tanaka
- Division of Gastroenterology and Hepatology, Department of Medicine, Nihon University School of Medicine, Tokyo, Japan
- Division of Gastroenterology and Hepatology, Graduate School of Medicine and Dental Sciences, Niigata University, Niigata, Japan
| | - Jun Inoue
- Division of Gastroenterology, Tohoku University Graduate School of Medicine, Sendai, Japan
| | - Atsunori Tsuchiya
- Division of Gastroenterology and Hepatology, Graduate School of Medicine and Dental Sciences, Niigata University, Niigata, Japan
| | - Shingo Nakamoto
- Department of Gastroenterology, Graduate School of Medicine, Chiba University, Chuo-ku, Chiba, Japan
| | - Ryuzo Abe
- Department of Emergency Medicine, Oita University, Oita, Japan
| | - Keiichi Fujiwara
- Department of Gastroenterology, Graduate School of Medicine, Chiba University, Chuo-ku, Chiba, Japan
| | - Osamu Yokosuka
- Department of Gastroenterology, Graduate School of Medicine, Chiba University, Chuo-ku, Chiba, Japan
| | - Ryosuke Suzuki
- Department of Virology II, National Institute of Infectious Diseases, Tokyo, Japan
| | - Koji Ishii
- Department of Quality Assurance and Radiological Protection, National Institute of Infectious Diseases, Tokyo, Japan
| | - Hiroshi Yotsuyanagi
- Division of Infectious Diseases, Advanced Clinical Research Center, Institute of Medical Science, University of Tokyo, Tokyo, Japan
- Department of Infectious Diseases and Applied Immunology, Hospital of the Institute of Medical Science, University of Tokyo, Tokyo, Japan
| | - Hiroaki Okamoto
- Division of Virology, Department of Infection and Immunity, Jichi Medical University School of Medicine, Shimotsuke, Tochigi, Japan
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Glitscher M, Spannaus IM, Behr F, Murra RO, Woytinek K, Bender D, Hildt E. The Protease Domain in HEV pORF1 Mediates the Replicase's Localization to Multivesicular Bodies and Its Exosomal Release. Cell Mol Gastroenterol Hepatol 2024; 17:589-605. [PMID: 38190941 PMCID: PMC10900777 DOI: 10.1016/j.jcmgh.2024.01.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/25/2023] [Revised: 01/03/2024] [Accepted: 01/03/2024] [Indexed: 01/10/2024]
Abstract
BACKGROUND A peculiar feature of the hepatitis E virus (HEV) is its reliance on the exosomal route for viral release. Genomic replication is mediated via the viral polyprotein pORF1, yet little is known about its subcellular localization. METHODS Subcellular localization of pORF1 and its subdomains, generated and cloned based on a structural prediciton of the viral replicase, was analyzed via confocal laser scanning microscopy. Exosomes released from cells were isolated via ultracentrifugation and analyzed by isopycnic density gradient centrifugation. This was followed by fluorimetry or Western blot analyses or reverse transcriptase-polymerase chain reaction to analyze separated particles in more detail. RESULTS We found pORF1 to be accumulating within the endosomal system, most dominantly to multivesicular bodies (MVBs). Expression of the polyprotein's 7 subdomains revealed that the papain-like cysteine-protease (PCP) is the only domain localizing like the full-length protein. A PCP-deficient pORF1 mutant lost its association to MVBs. Strikingly, both pORF1 and PCP can be released via exosomes. Similarly, genomic RNA still is released via exosomes in the absence of pORF2/3. CONCLUSIONS Taken together, we found that pORF1 localizes to MVBs in a PCP-dependent manner, which is followed by exosomal release. This reveals new aspects of HEV life cycle, because replication and release could be coupled at the endosomal interface. In addition, this may mediate capsid-independent spread or may facilitate the spread of viral infection, because genomes entering the cell during de novo infection readily encounter exosomally transferred pORF1.
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Affiliation(s)
- Mirco Glitscher
- Department of Virology, Paul-Ehrlich-Institute, Langen, Germany
| | | | - Fabiane Behr
- Department of Virology, Paul-Ehrlich-Institute, Langen, Germany
| | | | | | - Daniela Bender
- Department of Virology, Paul-Ehrlich-Institute, Langen, Germany
| | - Eberhard Hildt
- Department of Virology, Paul-Ehrlich-Institute, Langen, Germany.
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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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Morozov SY, Lezzhov AA, Solovyev AG. Predicted Membrane-Associated Domains in Proteins Encoded by Novel Monopartite Plant RNA Viruses Related to Members of the Family Benyviridae. Int J Mol Sci 2023; 24:12161. [PMID: 37569537 PMCID: PMC10418960 DOI: 10.3390/ijms241512161] [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: 06/28/2023] [Revised: 07/17/2023] [Accepted: 07/27/2023] [Indexed: 08/13/2023] Open
Abstract
As a continuation of our previous work, in this paper, we examine in greater detail the genome organization and some protein properties of the members of a potential group named Reclovirids and belonging to Benyviridae-related viruses. It can be proposed that the single-component Reclovirid genomes encode previously undiscovered transport genes. Indeed, analysis of the coding potential of these novel viral genomes reveals one or more cistrons ranging in size from 40 to 80 to about 600 codons, located in the 3'-terminal region of the genomic RNA, encoding proteins with predicted hydrophobic segments that are structurally diverse among Reclovirids and have no analogues in other plant RNA viruses. Additionally, in many cases, the possible methyltransferase domain of Reclovirid replicases is preceded by membrane-embedded protein segments that are not present in annotated members of the Benyviridae family. These observations suggest a general association of most Reclovirid proteins with cell membranes.
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Affiliation(s)
- Sergey Y. Morozov
- A. N. Belozersky Institute of Physico-Chemical Biology, Moscow State University, 119992 Moscow, Russia; (A.A.L.); (A.G.S.)
- Department of Virology, Biological Faculty, Moscow State University, 119234 Moscow, Russia
| | - Alexander A. Lezzhov
- A. N. Belozersky Institute of Physico-Chemical Biology, Moscow State University, 119992 Moscow, Russia; (A.A.L.); (A.G.S.)
| | - Andrey G. Solovyev
- A. N. Belozersky Institute of Physico-Chemical Biology, Moscow State University, 119992 Moscow, Russia; (A.A.L.); (A.G.S.)
- Department of Virology, Biological Faculty, Moscow State University, 119234 Moscow, Russia
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Dearborn AD, Kumar A, Marcotrigiano J. Learning more about hepatitis E virus. eLife 2023; 12:87047. [PMID: 36947136 PMCID: PMC10032651 DOI: 10.7554/elife.87047] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/23/2023] Open
Abstract
A domain in the ORF1 polyprotein of the hepatitis E virus that was previously thought to be a protease is actually a zinc-binding domain.
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Affiliation(s)
- Altaira D Dearborn
- Structural Virology Section, Laboratory of Infectious Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, United States
| | - Ashish Kumar
- Structural Virology Section, Laboratory of Infectious Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, United States
| | - Joseph Marcotrigiano
- Structural Virology Section, Laboratory of Infectious Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, United States
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