1
|
Woytinek K, Glitscher M, Hildt E. Antagonism of epidermal growth factor receptor signaling favors hepatitis E virus life cycle. J Virol 2024; 98:e0058024. [PMID: 38856640 PMCID: PMC11265270 DOI: 10.1128/jvi.00580-24] [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: 04/24/2024] [Accepted: 05/09/2024] [Indexed: 06/11/2024] Open
Abstract
Hepatitis E virus (HEV) poses a global threat, which currently remains understudied in terms of host interactions. Epidermal growth factor receptor (EGFR) plays multifaceted roles in viral pathogenesis, impacting host-cell entry, viral replication, and host-defense modulation. On the one hand, EGFR signaling emerged as a major driver in innate immunity; on the other hand, a crosstalk between HEV and EGFR requires deeper analysis. We therefore aimed to dissect the receptor's involvement in the HEV life cycle. In persistently HEV-infected cells, the EGFR amount is decreased alongside with enhanced receptor internalization. As compared with the control ligand-induced EGFR, activation revealed an early receptor internalization and degradation in HEV-replicating cells, resulting in a notable EGFR signaling delay. Interestingly, inhibition or silencing of EGFR increased viral replication, extracellular and intracellular viral transcripts, and released infectious particles. The pro-viral impact of EGFR inhibition was attributed to (i) impaired expression of interferon-stimulated genes, (ii) activation of the autophagosomal system, (iii) virus-induced inhibition of lysosomal acidification, and (iv) a decrease of the cellular cholesterol level. IMPORTANCE This study identifies epidermal growth factor receptor (EGFR) as a novel host factor affecting hepatitis E virus (HEV): EGFR downregulation promotes viral replication, release, and evasion from the innate immune response. The discovery that EGFR inhibition favors viral spread is particularly concerning for HEV patients undergoing EGFR inhibitor treatment.
Collapse
Affiliation(s)
| | - Mirco Glitscher
- Division of Virology, Paul Ehrlich Institute, Langen, Germany
| | - Eberhard Hildt
- Division of Virology, Paul Ehrlich Institute, Langen, Germany
| |
Collapse
|
2
|
Jiao F, Zhao Y, Zhou G, Meng C, Wang L, Wu S, Li J, Cao L, Zhou B, Luo Y, Jiao H. Multiple Functions of Hepatitis E Virus ORF3. Microorganisms 2024; 12:1405. [PMID: 39065173 PMCID: PMC11278674 DOI: 10.3390/microorganisms12071405] [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: 06/16/2024] [Revised: 07/05/2024] [Accepted: 07/08/2024] [Indexed: 07/28/2024] Open
Abstract
Hepatitis E (Hepatitis E, HE) is an acute and chronic infectious hepatitis caused by hepatitis E virus (Hepatitis E Virus, HEV) infection, which is responsible for most acute hepatitis in the world and is a significant public health problem. The pathogen, HEV, has three Open Reading Frames (ORFs) ORF1, ORF2, and ORF3, each of which has a different function. Most of the current research is focused on ORF1 and ORF2, while the research on ORF3 is still relatively small. To provide more ideas for the study of HEV pathogenesis and the prevention and treatment of HE, this paper reviews the effects of ORF3 on the ERK pathway, growth factors, immune response, and virus release.
Collapse
Affiliation(s)
- Fengyuan Jiao
- The College of Veterinary Medicine, Southwest University, Chongqing 402460, China; (F.J.); (G.Z.); (C.M.); (L.W.); (S.W.); (J.L.); (L.C.)
| | - Yu Zhao
- Ministry of Agriculture and Rural Affairs Key Laboratory of Crop Genitic Resources and Germplasm Innovation in Karst Region, Institute of Animal Husbandry and Veterinary Medicine of Guizhou Academy of Agricultural Science, Guiyang 550005, China;
| | - Gengxu Zhou
- The College of Veterinary Medicine, Southwest University, Chongqing 402460, China; (F.J.); (G.Z.); (C.M.); (L.W.); (S.W.); (J.L.); (L.C.)
| | - Chi Meng
- The College of Veterinary Medicine, Southwest University, Chongqing 402460, China; (F.J.); (G.Z.); (C.M.); (L.W.); (S.W.); (J.L.); (L.C.)
| | - Lingjie Wang
- The College of Veterinary Medicine, Southwest University, Chongqing 402460, China; (F.J.); (G.Z.); (C.M.); (L.W.); (S.W.); (J.L.); (L.C.)
| | - Shengping Wu
- The College of Veterinary Medicine, Southwest University, Chongqing 402460, China; (F.J.); (G.Z.); (C.M.); (L.W.); (S.W.); (J.L.); (L.C.)
| | - Jixiang Li
- The College of Veterinary Medicine, Southwest University, Chongqing 402460, China; (F.J.); (G.Z.); (C.M.); (L.W.); (S.W.); (J.L.); (L.C.)
| | - Liting Cao
- The College of Veterinary Medicine, Southwest University, Chongqing 402460, China; (F.J.); (G.Z.); (C.M.); (L.W.); (S.W.); (J.L.); (L.C.)
| | - Bo Zhou
- Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Yujinxiang Street 573, Changchun 130102, China;
| | - Yichen Luo
- The College of Veterinary Medicine, Southwest University, Chongqing 402460, China; (F.J.); (G.Z.); (C.M.); (L.W.); (S.W.); (J.L.); (L.C.)
| | - Hanwei Jiao
- The College of Veterinary Medicine, Southwest University, Chongqing 402460, China; (F.J.); (G.Z.); (C.M.); (L.W.); (S.W.); (J.L.); (L.C.)
| |
Collapse
|
3
|
Shahini E, Argentiero A, Andriano A, Losito F, Maida M, Facciorusso A, Cozzolongo R, Villa E. Hepatitis E Virus: What More Do We Need to Know? MEDICINA (KAUNAS, LITHUANIA) 2024; 60:998. [PMID: 38929615 PMCID: PMC11205503 DOI: 10.3390/medicina60060998] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/10/2024] [Revised: 06/14/2024] [Accepted: 06/17/2024] [Indexed: 06/28/2024]
Abstract
Hepatitis E virus (HEV) infection is typically a self-limiting, acute illness that spreads through the gastrointestinal tract but replicates in the liver. However, chronic infections are possible in immunocompromised individuals. The HEV virion has two shapes: exosome-like membrane-associated quasi-enveloped virions (eHEV) found in circulating blood or in the supernatant of infected cell cultures and non-enveloped virions ("naked") found in infected hosts' feces and bile to mediate inter-host transmission. Although HEV is mainly spread via enteric routes, it is unclear how it penetrates the gut wall to reach the portal bloodstream. Both virion types are infectious, but they infect cells in different ways. To develop personalized treatment/prevention strategies and reduce HEV impact on public health, it is necessary to decipher the entry mechanism for both virion types using robust cell culture and animal models. The contemporary knowledge of the cell entry mechanism for these two HEV virions as possible therapeutic target candidates is summarized in this narrative review.
Collapse
Affiliation(s)
- Endrit Shahini
- Gastroenterology Unit, National Institute of Gastroenterology-IRCCS “Saverio de Bellis”, Castellana Grotte, 70013 Bari, Italy; (F.L.); (R.C.)
| | | | - Alessandro Andriano
- Department of Precision and Regenerative Medicine and Ionian Area, University of Bari Aldo Moro Medical School, 70124 Bari, Italy;
| | - Francesco Losito
- Gastroenterology Unit, National Institute of Gastroenterology-IRCCS “Saverio de Bellis”, Castellana Grotte, 70013 Bari, Italy; (F.L.); (R.C.)
| | - Marcello Maida
- Gastroenterology and Endoscopy Unit, S. Elia-Raimondi Hospital, 93100 Caltanissetta, Italy;
| | - Antonio Facciorusso
- Department of Medical and Surgical Sciences, University of Foggia, 71122 Foggia, Italy;
| | - Raffaele Cozzolongo
- Gastroenterology Unit, National Institute of Gastroenterology-IRCCS “Saverio de Bellis”, Castellana Grotte, 70013 Bari, Italy; (F.L.); (R.C.)
| | - Erica Villa
- Gastroenterology Unit, CHIMOMO Department, University of Modena & Reggio Emilia, Via del Pozzo 71, 41121 Modena, Italy
| |
Collapse
|
4
|
Li X, Sun X, Pinpin J, Zhao Q, Sun Y. Multifunctional ORF3 protein of hepatitis E virus. J Med Virol 2024; 96:e29691. [PMID: 38783788 DOI: 10.1002/jmv.29691] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2024] [Revised: 04/23/2024] [Accepted: 05/14/2024] [Indexed: 05/25/2024]
Abstract
Hepatitis E virus (HEV) is an emerging zoonotic pathogen that is transmitted primarily through the fecal-oral route and can cause acute hepatitis in humans. Since HEV was identified as a zoonotic pathogen, different species of HEV strains have been globally identified from various hosts, leading to an expanding range of hosts. The HEV genome consists of a 5' noncoding region, three open reading frames (ORFs), and a 3' noncoding region. The ORF3 protein is the smallest but has many functions in HEV release and pathogenesis. In this review, we systematically summarize recent progress in understanding the functions of the HEV ORF3 protein in virion release, biogenesis of quasi-enveloped viruses, antigenicity, and host environmental regulation. This review will help us to understand HEV replication and pathogenesis mechanisms better.
Collapse
Affiliation(s)
- Xiaoxuan Li
- Department of Preventive Veterinary Medicine, College of Veterinary Medicine, Northwest Agriculture and Forestry University, Yangling, Shaanxi, China
| | - Xuwen Sun
- Department of Preventive Veterinary Medicine, College of Veterinary Medicine, Northwest Agriculture and Forestry University, Yangling, Shaanxi, China
| | - Ji Pinpin
- Department of Preventive Veterinary Medicine, College of Veterinary Medicine, Northwest Agriculture and Forestry University, Yangling, Shaanxi, China
| | - Qin Zhao
- Department of Preventive Veterinary Medicine, College of Veterinary Medicine, Northwest Agriculture and Forestry University, Yangling, Shaanxi, China
| | - Yani Sun
- Department of Preventive Veterinary Medicine, College of Veterinary Medicine, Northwest Agriculture and Forestry University, Yangling, Shaanxi, China
| |
Collapse
|
5
|
Lu Q, Wu H, Meng J, Wang J, Wu J, Liu S, Tong J, Nie J, Huang W. Multi-epitope vaccine design for hepatitis E virus based on protein ORF2 and ORF3. Front Microbiol 2024; 15:1372069. [PMID: 38577684 PMCID: PMC10991829 DOI: 10.3389/fmicb.2024.1372069] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2024] [Accepted: 03/07/2024] [Indexed: 04/06/2024] Open
Abstract
Introduction Hepatitis E virus (HEV), with heightened virulence in immunocompromised individuals and pregnant women, is a pervasive threat in developing countries. A globaly available vaccine against HEV is currently lacking. Methods We designed a multi-epitope vaccine based on protein ORF2 and ORF3 of HEV using immunoinformatics. Results The vaccine comprised 23 nontoxic, nonallergenic, soluble peptides. The stability of the docked peptide vaccine-TLR3 complex was validated by molecular dynamic simulations. The induction of effective cellular and humoral immune responses by the multi-peptide vaccine was verified by simulated immunization. Discussion These findings provide a foundation for future HEV vaccine studies.
Collapse
Affiliation(s)
- Qiong Lu
- Division of HIV/AIDS and Sex-transmitted Virus Vaccines, Institute for Biological Product Control, National Institutes for Food and Drug Control and WHO Collaborating Center for Standardization and Evaluation of Biologicals, Beijing, China
| | - Hao Wu
- Division of HIV/AIDS and Sex-transmitted Virus Vaccines, Institute for Biological Product Control, National Institutes for Food and Drug Control and WHO Collaborating Center for Standardization and Evaluation of Biologicals, Beijing, China
- Wuhan Institute of Biological Products Co., Ltd., Wuhan, China
| | - Jing Meng
- State Key Laboratory of Common Mechanism Research for Major Diseases, Suzhou Institute of Systems Medicine, Chinese Academy of Medical Sciences and Peking Union Medical College, Suzhou, Jiangsu, China
| | | | - Jiajing Wu
- Research and Development Department, Beijing Yunling Biotechnology Co., Ltd., Beijing, China
| | - Shuo Liu
- Changping Laboratory, Beijing, China
- Graduate School of Peking Union Medical College, Beijing, China
| | - Jincheng Tong
- Division of HIV/AIDS and Sex-transmitted Virus Vaccines, Institute for Biological Product Control, National Institutes for Food and Drug Control and WHO Collaborating Center for Standardization and Evaluation of Biologicals, Beijing, China
| | - Jianhui Nie
- Division of HIV/AIDS and Sex-transmitted Virus Vaccines, Institute for Biological Product Control, National Institutes for Food and Drug Control and WHO Collaborating Center for Standardization and Evaluation of Biologicals, Beijing, China
| | - Weijin Huang
- Division of HIV/AIDS and Sex-transmitted Virus Vaccines, Institute for Biological Product Control, National Institutes for Food and Drug Control and WHO Collaborating Center for Standardization and Evaluation of Biologicals, Beijing, China
| |
Collapse
|
6
|
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.
Collapse
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.
| |
Collapse
|
7
|
Ju X, Dong L, Ding Q. Hepatitis E Virus Life Cycle. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2023; 1417:141-157. [PMID: 37223864 DOI: 10.1007/978-981-99-1304-6_10] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Hepatitis E virus (HEV) infects over 20 million people worldwide per year, leading to 30,000-40,000 deaths. In most cases HEV infection in a self-limited, acute illness. However, chronic infections could occur in immunocompromised individuals. Due to scarcity of robust cell culture models in vitro and genetic tractable animal models in vivo, the details of HEV life cycle, as well as its interaction with host cells still remain elusive, which dampens antivirals discovery. In this chapter, we present an update in the HEV infectious cycle steps: entry, genome replication/subgenomic RNA transcription, assembly, and release. Moreover, we discussed the future prospective on HEV research and illustrates important questions urgently to be addressed.
Collapse
Affiliation(s)
- Xiaohui Ju
- School of Medicine, Tsinghua University, Beijing, China
| | - Lin Dong
- School of Medicine, Tsinghua University, Beijing, China
| | - Qiang Ding
- School of Medicine, Tsinghua University, Beijing, China.
| |
Collapse
|
8
|
Liu X, Qi S, Yin X. Morphogenesis of Hepatitis E Virus. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2023; 1417:159-169. [PMID: 37223865 DOI: 10.1007/978-981-99-1304-6_11] [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, a leading cause of acute hepatitis worldwide, has been recognized as non-enveloped virus since its discovery in the 1980s. However, the recent identification of lipid membrane-associated form termed as "quasi-enveloped" HEV has changed this long-held notion. Both naked HEV and quasi-enveloped HEV play important roles in the pathogenesis of hepatitis E. However, the biogenesis and the mechanisms underlying the composition, biogenesis regulation, and functions of the novel quasi-enveloped virions remain enigmatic. In this chapter, we highlight the most recent discoveries on the dual life cycle of these two different types of virions, and further discuss the implication of the quasi-envelopment in our understanding of the molecular biology of HEV.
Collapse
Affiliation(s)
- Xing Liu
- State Key Laboratory for Animal Disease Control and Prevention, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, China
| | - Shuhui Qi
- State Key Laboratory for Animal Disease Control and Prevention, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, China
| | - Xin Yin
- State Key Laboratory for Animal Disease Control and Prevention, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, China.
| |
Collapse
|
9
|
He Q, Zhang Y, Gong W, Zeng H, Wang L. Genetic Evolution of Hepatitis E Virus. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2023; 1417:59-72. [PMID: 37223859 DOI: 10.1007/978-981-99-1304-6_5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Comparative analysis of the genomic sequences of multiple hepatitis E virus (HEV) isolates has revealed extensive genomic diversity among them. Recently, a variety of genetically distinct HEV variants have also been isolated and identified from large numbers of animal species, including birds, rabbits, rats, ferrets, bats, cutthroat trout, and camels, among others. Furthermore, it has been reported that recombination in HEV genomes takes place in animals and in human patients. Also, chronic HEV infection in immunocompromised individuals has revealed the presence of viral strains carrying insertions from human genes. This paper reviews current knowledge on the genomic variability and evolution of HEV.
Collapse
Affiliation(s)
- Qiyu He
- Department of Microbiology and Infectious Disease Center, School of Basic Medical Sciences, Peking University Health Science Center, Beijing, China
| | - Yulin Zhang
- Department of Microbiology and Infectious Disease Center, School of Basic Medical Sciences, Peking University Health Science Center, Beijing, China
| | - Wanyun Gong
- Department of Microbiology and Infectious Disease Center, School of Basic Medical Sciences, Peking University Health Science Center, Beijing, China
| | - Hang Zeng
- Department of Microbiology and Infectious Disease Center, School of Basic Medical Sciences, Peking University Health Science Center, Beijing, China
| | - Ling Wang
- Department of Microbiology and Infectious Disease Center, School of Basic Medical Sciences, Peking University Health Science Center, Beijing, China.
| |
Collapse
|
10
|
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.
Collapse
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.
| |
Collapse
|
11
|
Cancela F, Noceti O, Arbiza J, Mirazo S. Structural aspects of hepatitis E virus. Arch Virol 2022; 167:2457-2481. [PMID: 36098802 PMCID: PMC9469829 DOI: 10.1007/s00705-022-05575-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2022] [Accepted: 06/04/2022] [Indexed: 12/14/2022]
Abstract
Hepatitis E virus (HEV) is a leading cause of acute hepatitis worldwide. Hepatitis E is an enterically transmitted zoonotic disease that causes large waterborne epidemic outbreaks in developing countries and has become an increasing public-health concern in industrialized countries. In this setting, the infection is usually acute and self-limiting in immunocompetent individuals, although chronic cases in immunocompromised patients have been reported, frequently associated with several extrahepatic manifestations. Moreover, extrahepatic manifestations have also been reported in immunocompetent individuals with acute HEV infection. HEV belongs to the alphavirus-like supergroup III of single-stranded positive-sense RNA viruses, and its genome contains three partially overlapping open reading frames (ORFs). ORF1 encodes a nonstructural protein with eight domains, most of which have not been extensively characterized: methyltransferase, Y domain, papain-like cysteine protease, hypervariable region, proline-rich region, X domain, Hel domain, and RNA-dependent RNA polymerase. ORF2 and ORF3 encode the capsid protein and a multifunctional protein believed to be involved in virion release, respectively. The novel ORF4 is only expressed in HEV genotype 1 under endoplasmic reticulum stress conditions, and its exact function has not yet been elucidated. Despite important advances in recent years, the biological and molecular processes underlying HEV replication remain poorly understood, primarily due to a lack of detailed information about the functions of the viral proteins and the mechanisms involved in host-pathogen interactions. This review summarizes the current knowledge concerning HEV proteins and their biological properties, providing updated detailed data describing their function and focusing in detail on their structural characteristics. Furthermore, we review some unclear aspects of the four proteins encoded by the ORFs, highlighting the current key information gaps and discussing potential novel experimental strategies for shedding light on those issues.
Collapse
Affiliation(s)
- Florencia Cancela
- grid.11630.350000000121657640Sección Virología, Facultad de Ciencias, Universidad de la República, Montevideo, Uruguay
| | - Ofelia Noceti
- grid.414402.70000 0004 0469 0889Programa Nacional de Trasplante Hepático y Unidad Docente Asistencial Centro Nacional de Tratamiento Hepatobiliopancreatico. Hospital Central de las Fuerzas Armadas, Montevideo, Uruguay
| | - Juan Arbiza
- grid.11630.350000000121657640Sección Virología, Facultad de Ciencias, Universidad de la República, Montevideo, Uruguay
| | - Santiago Mirazo
- grid.11630.350000000121657640Sección Virología, Facultad de Ciencias, Universidad de la República, Montevideo, Uruguay ,grid.11630.350000000121657640Departamento de Bacteriología y Virología, Instituto de Higiene, Facultad de Medicina, Universidad de la República, Montevideo, Uruguay ,Av. Alfredo Navarro 3051, PC 11600 Montevideo, Uruguay
| |
Collapse
|
12
|
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.
Collapse
|
13
|
Glitscher M, Hildt E. Hepatitis E virus egress and beyond - the manifold roles of the viral ORF3 protein. Cell Microbiol 2021; 23:e13379. [PMID: 34272798 DOI: 10.1111/cmi.13379] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2021] [Revised: 06/18/2021] [Accepted: 07/06/2021] [Indexed: 11/30/2022]
Abstract
Although the hepatitis E virus represents an uprising threat to the global community by representing the commonest cause of an acute viral hepatitis worldwide, its life cycle is grossly understudied. Albeit HEV is a non-enveloped virus, its progeny is released as quasi-enveloped virions. Thus, the responsible accessory protein pORF3 gained rising attention in the past years. It mediates viral release via the exosomal route by targeting the viral capsid to the endosomal system, more precisely to multivesicular bodies. As this is followed by quasi-envelopment, pORF3 may in terms represent a substitute to a conventional envelope protein. This feature proofs to be rather unique with respect to other enteric viruses, although the protein's role in the viral life cycle seems to reach far beyond simply maintaining release of progeny viruses. How pORF3 affects viral morphogenesis, how it mediates efficient viral release and how it supports viral spread is summarised in this microreview. With this, we aim to shed light on functions of pORF3 to gain further insights in still enigmatic aspects of the HEV life cycle. TAKE AWAYS: HEV is released as exosome via multivesicular bodies Viral pORF3 mediates release via endosomal complexes required for transport pORF3 modulates various cellular processes in infected cells Elucidation of pORF3-related processes imply novel clinical strategies.
Collapse
Affiliation(s)
| | - Eberhard Hildt
- Department Virology, Paul-Ehrlich-Institut, Langen, Germany
| |
Collapse
|
14
|
Advances in Hepatitis E Virus Biology and Pathogenesis. Viruses 2021; 13:v13020267. [PMID: 33572257 PMCID: PMC7915517 DOI: 10.3390/v13020267] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2020] [Revised: 01/21/2021] [Accepted: 02/02/2021] [Indexed: 02/07/2023] Open
Abstract
Hepatitis E virus (HEV) is one of the causative agents for liver inflammation across the world. HEV is a positive-sense single-stranded RNA virus. Human HEV strains mainly belong to four major genotypes in the genus Orthohepevirus A, family Hepeviridae. Among the four genotypes, genotype 1 and 2 are obligate human pathogens, and genotype 3 and 4 cause zoonotic infections. HEV infection with genotype 1 and 2 mainly presents as acute and self-limiting hepatitis in young adults. However, HEV infection of pregnant women with genotype 1 strains can be exacerbated to fulminant hepatitis, resulting in a high rate of case fatality. As pregnant women maintain the balance of maternal-fetal tolerance and effective immunity against invading pathogens, HEV infection with genotype 1 might dysregulate the balance and cause the adverse outcome. Furthermore, HEV infection with genotype 3 can be chronic in immunocompromised patients, with rapid progression, which has been a challenge since it was reported years ago. The virus has a complex interaction with the host cells in downregulating antiviral factors and recruiting elements to generate a conducive environment of replication. The virus-cell interactions at an early stage might determine the consequence of the infection. In this review, advances in HEV virology, viral life cycle, viral interference with the immune response, and the pathogenesis in pregnant women are discussed, and perspectives on these aspects are presented.
Collapse
|
15
|
Zahmanova G, Mazalovska M, Takova K, Toneva V, Minkov I, Peyret H, Lomonossoff G. Efficient Production of Chimeric Hepatitis B Virus-Like Particles Bearing an Epitope of Hepatitis E Virus Capsid by Transient Expression in Nicotiana benthamiana. Life (Basel) 2021; 11:life11010064. [PMID: 33477348 PMCID: PMC7830250 DOI: 10.3390/life11010064] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2020] [Revised: 01/13/2021] [Accepted: 01/14/2021] [Indexed: 12/12/2022] Open
Abstract
The core antigen of hepatitis B virus (HBcAg) is capable of self-assembly into virus-like particles (VLPs) when expressed in a number of heterologous systems. Such VLPs are potential carriers of foreign antigenic sequences for vaccine design. In this study, we evaluated the production of chimeric HBcAg VLPs presenting a foreign epitope on their surface, the 551–607 amino acids (aa) immunological epitope of the ORF2 capsid protein of hepatitis E virus. A chimeric construct was made by the insertion of 56 aa into the immunodominant loop of the HBcAg. The sequences encoding the chimera were inserted into the pEAQ-HT vector and infiltrated into Nicotiana benthamiana leaves. The plant-expressed chimeric HBcHEV ORF2 551–607 protein was recognized by an anti-HBcAg mAb and anti-HEV IgG positive swine serum. Electron microscopy showed that plant-produced chimeric protein spontaneously assembled into “knobbly” ~34 nm diameter VLPs. This study shows that HBcAg is a promising carrier platform for the neutralizing epitopes of hepatitis E virus (HEV) and the chimeric HBcAg/HEV VLPs could be a candidate for a bivalent vaccine.
Collapse
Affiliation(s)
- Gergana Zahmanova
- Department of Plant Physiology and Molecular Biology, University of Plovdiv, 4000 Plovdiv, Bulgaria; (M.M.); (K.T.); (V.T.)
- Center of Plant Systems Biology and Biotechnology, 4000 Plovdiv, Bulgaria;
- Correspondence: (G.Z.); (G.L.); Tel.: +359-32-261529 (G.Z.); +44-1603-450351 (G.L.)
| | - Milena Mazalovska
- Department of Plant Physiology and Molecular Biology, University of Plovdiv, 4000 Plovdiv, Bulgaria; (M.M.); (K.T.); (V.T.)
| | - Katerina Takova
- Department of Plant Physiology and Molecular Biology, University of Plovdiv, 4000 Plovdiv, Bulgaria; (M.M.); (K.T.); (V.T.)
| | - Valentina Toneva
- Department of Plant Physiology and Molecular Biology, University of Plovdiv, 4000 Plovdiv, Bulgaria; (M.M.); (K.T.); (V.T.)
- Institute of Molecular Biology and Biotechnologies, 4108 Markovo, Bulgaria
| | - Ivan Minkov
- Center of Plant Systems Biology and Biotechnology, 4000 Plovdiv, Bulgaria;
- Institute of Molecular Biology and Biotechnologies, 4108 Markovo, Bulgaria
| | - Hadrien Peyret
- Department of Biological Chemistry, John Innes Centre, Norwich Research Park, Colney NR4 7UH, UK;
| | - George Lomonossoff
- Department of Biological Chemistry, John Innes Centre, Norwich Research Park, Colney NR4 7UH, UK;
- Correspondence: (G.Z.); (G.L.); Tel.: +359-32-261529 (G.Z.); +44-1603-450351 (G.L.)
| |
Collapse
|
16
|
Boumaiza M, Trabelsi K, Choucha Z, Akrouti I, Leone S, Picone D, Kallel H. Production and characterization of a fusion form of hepatitis E virus tORF2 capsid protein in Escherichia coli. Prep Biochem Biotechnol 2020; 51:562-569. [PMID: 33095097 DOI: 10.1080/10826068.2020.1836656] [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: 10/23/2022]
Abstract
Hepatitis E virus (HEV) is a nonenveloped virus causing an emerging zoonotic disease posing a severe threat to the public health in the world, especially to pregnant women. In this study, a truncated form (aa 368-606) of the open reading frame 2 of the capsid protein (tORF2-HEV), a major structural protein of HEV, was expressed in Escherichia coli. This work characterizes for the first time, the fused Glutathione-S-Transferase-tagged tORF2 (GST-tORF2) and tORF2-HEV forms in E. coli. The fusion protein was purified by affinity chromatography with a purity higher than 90% and to yield about 27% after thrombin digestion. The purified GST-tORF2 protein was then characterized by western blot, using anti-GST antibodies, and CD spectroscopy. The GST-tORF2 and tORF2-HEV proteins were shown to be efficient to develop an ELISA test to detect anti-HEV IgG in mice sera immunized with a recombinant full length ORF2 protein. Sera showed a significant increase of the absorbance signal at 450 nm, in plate wells coated with a quantity of 0.5, 1 and 2 µg of proteins. ELISA plates coated with the purified GST-tORF2 and tORF2-HEV showed similar response when compared to the HEV ELISA where total insect cell lysate, infected with the recombinant baculovirus expressing full ORF2, was used as positive control.
Collapse
Affiliation(s)
- Mohamed Boumaiza
- Laboratory of Molecular Microbiology, Vaccinology and Biotechnology Development, Group of Biotechnology Development, Institut Pasteur de Tunis, Université Tunis El Manar, Tunis, Tunisia
| | - Khaled Trabelsi
- Laboratory of Molecular Microbiology, Vaccinology and Biotechnology Development, Group of Biotechnology Development, Institut Pasteur de Tunis, Université Tunis El Manar, Tunis, Tunisia.,Life Science Department, Biotechnology Programme, College of Graduate Studies, Arabian Gulf University, Manama, Bahrain
| | - Zeineb Choucha
- Laboratory of Molecular Microbiology, Vaccinology and Biotechnology Development, Group of Biotechnology Development, Institut Pasteur de Tunis, Université Tunis El Manar, Tunis, Tunisia
| | - Ines Akrouti
- Laboratory of Molecular Microbiology, Vaccinology and Biotechnology Development, Group of Biotechnology Development, Institut Pasteur de Tunis, Université Tunis El Manar, Tunis, Tunisia
| | - Serena Leone
- Department of Chemical Sciences, University of Naples Federico II, Naples, Italy
| | - Delia Picone
- Department of Chemical Sciences, University of Naples Federico II, Naples, Italy
| | - Héla Kallel
- Laboratory of Molecular Microbiology, Vaccinology and Biotechnology Development, Group of Biotechnology Development, Institut Pasteur de Tunis, Université Tunis El Manar, Tunis, Tunisia.,UnivercellsVaccines, Nivelles, Belgium
| |
Collapse
|
17
|
Virus-Host Cell Interplay during Hepatitis E Virus Infection. Trends Microbiol 2020; 29:309-319. [PMID: 32828646 PMCID: PMC7437515 DOI: 10.1016/j.tim.2020.07.002] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2020] [Revised: 06/26/2020] [Accepted: 07/22/2020] [Indexed: 12/11/2022]
Abstract
The molecular interplay between cellular host factors and viral proteins is a continuous process throughout the viral life cycle determining virus host range and pathogenesis. The hepatitis E virus (HEV) is a long-neglected RNA virus and the major causative agent of acute viral hepatitis in humans worldwide. However, the mechanisms of liver pathology and clinical disease remain poorly understood for HEV infection. This review summarizes our current understanding of HEV-host cell interactions and highlights experimental strategies and techniques to identify novel host components required for the viral life cycle as well as restriction factors. Understanding these interactions will provide insight into the viral life cycle of HEV and might further help to devise novel therapeutic strategies and antiviral targets.
Collapse
|
18
|
On the Host Side of the Hepatitis E Virus Life Cycle. Cells 2020; 9:cells9051294. [PMID: 32456000 PMCID: PMC7291229 DOI: 10.3390/cells9051294] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2020] [Revised: 05/20/2020] [Accepted: 05/21/2020] [Indexed: 12/12/2022] Open
Abstract
Hepatitis E virus (HEV) infection is one of the most common causes of acute hepatitis in the world. HEV is an enterically transmitted positive-strand RNA virus found as a non-enveloped particle in bile as well as stool and as a quasi-enveloped particle in blood. Current understanding of the molecular mechanisms and host factors involved in productive HEV infection is incomplete, but recently developed model systems have facilitated rapid progress in this area. Here, we provide an overview of the HEV life cycle with a focus on the host factors required for viral entry, RNA replication, assembly and release. Further developments of HEV model systems and novel technologies should yield a broader picture in the future.
Collapse
|
19
|
Rapid High-Yield Transient Expression of Swine Hepatitis E ORF2 Capsid Proteins in Nicotiana benthamiana Plants and Production of Chimeric Hepatitis E Virus-Like Particles Bearing the M2e Influenza Epitope. PLANTS 2019; 9:plants9010029. [PMID: 31878256 PMCID: PMC7020208 DOI: 10.3390/plants9010029] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/27/2019] [Revised: 12/12/2019] [Accepted: 12/21/2019] [Indexed: 12/27/2022]
Abstract
The Hepatitis E virus (HEV) is a causative agent of acute hepatitis, mainly transmitted by the fecal-oral route or zoonotic. Open reading frame (ORF) 2 encodes the viral capsid protein, which is essential for virion assembly, host interaction, and inducing neutralizing antibodies. In this study, we investigated whether full-length and N- and C-terminally modified versions of the capsid protein transiently expressed in N. benthamiana plants could assemble into highly-immunogenic, virus-like particles (VLPs). We also assessed whether such VLPs can act as a carrier of foreign immunogenic epitopes, such as the highly-conserved M2e peptide from the Influenza virus. Plant codon-optimized HEV ORF2 capsid genes were constructed in which the nucleotides coding the N-terminal, the C-terminal, or both parts of the protein were deleted. The M2e peptide was inserted into the P2 loop after the residue Gly556 of HEV ORF2 protein by gene fusion, and three different chimeric constructs were designed. Plants expressed all versions of the HEV capsid protein up to 10% of total soluble protein (TSP), including the chimeras, but only the capsid protein consisting of aa residues 110 to 610 (HEV 110–610) and chimeric M2 HEV 110–610 spontaneously assembled in higher order structures. The chimeric VLPs assembled into particles with 22–36 nm in diameter and specifically reacted with the anti-M2e antibody.
Collapse
|
20
|
Hepatitis E virus infections in Europe. J Clin Virol 2019; 120:20-26. [DOI: 10.1016/j.jcv.2019.09.004] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2019] [Accepted: 09/06/2019] [Indexed: 12/11/2022]
|
21
|
Abstract
Hepatitis E virus (HEV) infection is a major cause of acute hepatitis worldwide. It is transmitted enterically but replicates in the liver. Recent studies indicate that HEV exists in two forms: naked, nonenveloped virions that are shed into feces to mediate inter-host transmission, and membrane-cloaked, quasienveloped virions that circulate in the bloodstream to mediate virus spread within a host. Both virion types are infectious, but differ in the way they infect cells. Elucidating the entry mechanism for both virion types is essential to understand HEV biology and pathogenesis, and is relevant to the development of treatments and preventions for HEV. This review summarizes the current understanding of the cell entry mechanism for these two HEV virion types.
Collapse
Affiliation(s)
- Xin Yin
- Center for Vaccines and Immunity, The Research Institute at Nationwide Children's Hospital, Columbus, OH 43205, USA.
| | - Zongdi Feng
- Center for Vaccines and Immunity, The Research Institute at Nationwide Children's Hospital, Columbus, OH 43205, USA.
- Department of Pediatrics, The Ohio State University College of Medicine, Columbus, OH 43210, USA.
| |
Collapse
|
22
|
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.
Collapse
|
23
|
Hepatitis E Virus Assembly and Release. Viruses 2019; 11:v11060539. [PMID: 31181848 PMCID: PMC6631228 DOI: 10.3390/v11060539] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2019] [Revised: 05/31/2019] [Accepted: 06/07/2019] [Indexed: 12/12/2022] Open
Abstract
Hepatitis E is an underestimated threat to public health, caused by the hepatitis E virus (HEV). HEV is the most common cause of acute viral hepatitis in the world, with no available direct-acting antiviral treatment. According to a recent WHO report, 20 million people become infected with HEV annually, resulting in 44,000 deaths. However, due to the scarcity of efficient in vitro cell culture systems for HEV, our knowledge of the life cycle of HEV is incomplete. Recently, significant progress has been made towards gaining a more comprehensive view of the HEV life cycle, as several in vitro culturing systems have been developed in recent years. Here, we review current knowledge and recent advances with regard to the HEV life cycle, with a particular focus on the assembly and release of viral particles. We also discuss the knowledge gaps in HEV assembly and release. Meanwhile, we highlight experimental platforms that could potentially be utilized to fill these gaps. Lastly, we offer perspectives on the future of research into HEV virology and its interaction with host cells.
Collapse
|
24
|
Zhang XL, Li WF, Yuan S, Guo JY, Li ZL, Chi SH, Huang WJ, Li XW, Huang SJ, Shao JW. Meta-transcriptomic analysis reveals a new subtype of genotype 3 avian hepatitis E virus in chicken flocks with high mortality in Guangdong, China. BMC Vet Res 2019; 15:131. [PMID: 31060564 PMCID: PMC6503432 DOI: 10.1186/s12917-019-1884-y] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2018] [Accepted: 04/25/2019] [Indexed: 02/07/2023] Open
Abstract
Background Hepatitis E virus (HEV) is one of most important zoonotic viruses, and it can infect a wide range of host species. Avian HEV has been identified as the aetiological agent of big liver and spleen disease or hepatitis-splenomegaly syndrome in chickens. HEV infection is common among chicken flocks in China, and there are currently no practical measures for preventing the spread of the disease. The predominant avian HEV genotype circulating in China have been identified as genotype 3 strains, although some novel genotypes have also been identified from chicken flocks in China. Results In this study, we used a meta-transcriptomics approach to identify a new subtype of genotype 3 avian HEV in broiler chickens at a poultry farm located in Shenzhen, Guangdong Province, China. The complete genome sequence of the avian HEV, designated CaHEV-GDSZ01, is 6655-nt long, including a 5′ UTR of 24 nt and a 3′ UTR of 125 nt (excluding the poly(A) tail), and contains three open reading frames (ORFs). Sequence analysis indicated that the complete ORF1 (4599 nt/1532 aa), ORF2 (1821 nt/606 aa) and ORF3 (264 nt/87 aa) of CaHEV-GDSZ01 share the highest nucleotide sequence identity (85.8, 86.7 and 95.8%, respectively) with the corresponding ORFs of genotype 3 avian HEV. Phylogenetic analyses further demonstrated that the avian HEV identified in this study is a new subtype of genotype 3 avian HEV. Conclusions Our results demonstrate that a new subtype of genotype 3 avian HEV is endemic in Guangdong, China, and could cause high mortality in infected chickens. This study also provides full genomic data for better understanding the evolutionary relationships of avian HEV circulating in China. Altogether, the results presented in this study suggest that more attention should be paid to avian HEV and its potential disease manifestation.
Collapse
Affiliation(s)
- Xue-Lian Zhang
- Key Laboratory for Preventive Research of Emerging Animal Diseases, Foshan University, Foshan, 528231, Guangdong, China.,College of Life Science and Engineering, Foshan University, Foshan, 528231, Guangdong, China
| | - Wen-Feng Li
- College of Life Science and Engineering, Foshan University, Foshan, 528231, Guangdong, China
| | - Sheng Yuan
- College of Life Science and Engineering, Foshan University, Foshan, 528231, Guangdong, China
| | - Jin-Yue Guo
- Key Laboratory for Preventive Research of Emerging Animal Diseases, Foshan University, Foshan, 528231, Guangdong, China.,College of Life Science and Engineering, Foshan University, Foshan, 528231, Guangdong, China
| | - Zhi-Li Li
- Key Laboratory for Preventive Research of Emerging Animal Diseases, Foshan University, Foshan, 528231, Guangdong, China.,College of Life Science and Engineering, Foshan University, Foshan, 528231, Guangdong, China
| | - Shi-Hong Chi
- College of Life Science and Engineering, Foshan University, Foshan, 528231, Guangdong, China
| | - Wen-Jing Huang
- College of Life Science and Engineering, Foshan University, Foshan, 528231, Guangdong, China
| | - Xiao-Wen Li
- College of Life Science and Engineering, Foshan University, Foshan, 528231, Guangdong, China
| | - Shu-Jian Huang
- Key Laboratory for Preventive Research of Emerging Animal Diseases, Foshan University, Foshan, 528231, Guangdong, China. .,College of Life Science and Engineering, Foshan University, Foshan, 528231, Guangdong, China.
| | - Jian-Wei Shao
- Key Laboratory for Preventive Research of Emerging Animal Diseases, Foshan University, Foshan, 528231, Guangdong, China. .,College of Life Science and Engineering, Foshan University, Foshan, 528231, Guangdong, China. .,Department of Medical Microbiology and Parasitology, Zhejiang University School of Medicine, Hangzhou, 310058, Zhejiang, China.
| |
Collapse
|
25
|
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.
Collapse
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
| |
Collapse
|
26
|
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.
Collapse
|
27
|
Life cycle and morphogenesis of the hepatitis E virus. Emerg Microbes Infect 2018; 7:196. [PMID: 30498191 PMCID: PMC6265337 DOI: 10.1038/s41426-018-0198-7] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2018] [Revised: 11/01/2018] [Accepted: 11/05/2018] [Indexed: 12/19/2022]
Abstract
Hepatitis E virus (HEV) is transmitted primarily via contaminated water and food by the fecal oral route and causes epidemics in developing countries. In industrialized countries, zoonotic transmission of HEV is prevalent. In addition, HEV is the major cause of acute hepatitis in healthy adults and can cause chronic hepatitis in immunocompromised patients, with pregnant HEV-infected women having increased mortality rates of approximately 25%. HEV was once an understudied and neglected virus. However, in recent years, the safety of blood products with respect to HEV has increasingly been considered to be a public health problem. The establishment of HEV infection models has enabled significant progress to be made in understanding its life cycle. HEV infects cells via a receptor (complex) that has yet to be identified. The HEV replication cycle is initiated immediately after the (+) stranded RNA genome is released into the cell cytosol. Subsequently, infectious viral particles are released by the ESCRT complex as quasi-enveloped viruses (eHEVs) into the serum, whereas feces and urine contain only nonenveloped infectious viral progeny. The uncoating of the viral envelope takes place in the biliary tract, resulting in the generation of a nonenveloped virus that is more resistant to environmental stress and possesses a higher infectivity than that of eHEV. This review summarizes the current knowledge regarding the HEV life cycle, viral morphogenesis, established model systems and vaccine development.
Collapse
|
28
|
Todt D, Meister TL, Steinmann E. Hepatitis E virus treatment and ribavirin therapy: viral mechanisms of nonresponse. Curr Opin Virol 2018; 32:80-87. [PMID: 30384328 DOI: 10.1016/j.coviro.2018.10.001] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2018] [Revised: 09/27/2018] [Accepted: 10/04/2018] [Indexed: 02/07/2023]
Abstract
Hepatitis E virus (HEV) can cause chronic infections in immunosuppressed patients with adverse clinical outcomes. Intervention strategies are limited with ribavirin (RBV) being the only main therapeutic option as off-label drug. Recent reports on RBV monotherapy failures show a coherence with the presence of certain single nucleotide variants (SNVs) and in-frame insertions in the hypervariable region of open reading frame 1 in the HEV genome. Importantly, some of the alterations were present in the viral population as minor variant before RBV administration. Individualized infection medicine by early detection of emerging viral variants in patients could improve treatment outcome and prognosis.
Collapse
Affiliation(s)
- Daniel Todt
- Department of Molecular and Medical Virology, Ruhr-University Bochum, Bochum, Germany
| | - Toni Luise Meister
- Department of Molecular and Medical Virology, Ruhr-University Bochum, Bochum, Germany
| | - Eike Steinmann
- Department of Molecular and Medical Virology, Ruhr-University Bochum, Bochum, Germany.
| |
Collapse
|
29
|
Pavesi A, Vianelli A, Chirico N, Bao Y, Blinkova O, Belshaw R, Firth A, Karlin D. Overlapping genes and the proteins they encode differ significantly in their sequence composition from non-overlapping genes. PLoS One 2018; 13:e0202513. [PMID: 30339683 PMCID: PMC6195259 DOI: 10.1371/journal.pone.0202513] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2018] [Accepted: 08/03/2018] [Indexed: 11/19/2022] Open
Abstract
Overlapping genes represent a fascinating evolutionary puzzle, since they encode two functionally unrelated proteins from the same DNA sequence. They originate by a mechanism of overprinting, in which point mutations in an existing frame allow the expression (the "birth") of a completely new protein from a second frame. In viruses, in which overlapping genes are abundant, these new proteins often play a critical role in infection, yet they are frequently overlooked during genome annotation. This results in erroneous interpretation of mutational studies and in a significant waste of resources. Therefore, overlapping genes need to be correctly detected, especially since they are now thought to be abundant also in eukaryotes. Developing better detection methods and conducting systematic evolutionary studies require a large, reliable benchmark dataset of known cases. We thus assembled a high-quality dataset of 80 viral overlapping genes whose expression is experimentally proven. Many of them were not present in databases. We found that overall, overlapping genes differ significantly from non-overlapping genes in their nucleotide and amino acid composition. In particular, the proteins they encode are enriched in high-degeneracy amino acids and depleted in low-degeneracy ones, which may alleviate the evolutionary constraints acting on overlapping genes. Principal component analysis revealed that the vast majority of overlapping genes follow a similar composition bias, despite their heterogeneity in length and function. Six proven mammalian overlapping genes also followed this bias. We propose that this apparently near-universal composition bias may either favour the birth of overlapping genes, or/and result from selection pressure acting on them.
Collapse
Affiliation(s)
- Angelo Pavesi
- Department of Chemistry, Life Sciences and Environmental Sustainability, University of Parma, Parma, Italy
| | - Alberto Vianelli
- Department of Theoretical and Applied Sciences, University of Insubria, Varese, Italy
| | - Nicola Chirico
- Department of Theoretical and Applied Sciences, University of Insubria, Varese, Italy
| | - Yiming Bao
- BIG Data Center, Beijing Institute of Genomics, Chinese Academy of Sciences, Beijing, China
| | - Olga Blinkova
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, MD, United States of America
| | - Robert Belshaw
- School of Biomedical & Healthcare Sciences, Plymouth University Peninsula Schools of Medicine and Dentistry (PUPSMD), Plymouth, United Kingdom
| | - Andrew Firth
- Department of Pathology, Division of Virology, University of Cambridge, Cambridge, United Kingdom
| | - David Karlin
- Department of Zoology, University of Oxford, Oxford, United Kingdom
- Division of Structural Biology, University of Oxford, Oxford, United Kingdom
| |
Collapse
|
30
|
Su Q, Li Y, Zhang Y, Zhang Z, Meng F, Cui Z, Chang S, Zhao P. Characterization of the novel genotype avian hepatitis E viruses from outbreaks of hepatic rupture haemorrhage syndrome in different geographical regions of China. Transbound Emerg Dis 2018; 65:2017-2026. [PMID: 30086212 DOI: 10.1111/tbed.12987] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2018] [Revised: 08/01/2018] [Accepted: 08/02/2018] [Indexed: 12/21/2022]
Abstract
Since 2016, hepatic rupture haemorrhage syndrome (HRHS) has emerged in layer and broiler breeder hens in several provinces of China, and novel genotype avian hepatitis E viruses were detected from these chickens. To gain a better understanding of the genetic properties of the novel avian HEV strain, the capsid gene of four isolates from birds at four farms experiencing HRHS in different geographical regions were determined and compared with those of reported pathogenic and nonpathogenic avian HEV isolates as well as mammalian HEVs. Results showed that all those isolates share 80.1%-88.2% nucleotide sequence identity and 89.3%-91.9% amino acid sequence identity with other published avian HEV strains, while phylogenetic analysis further demonstrate that a novel genotype avian HEV was epidemic in China. Meanwhile, sequence analysis revealed that those novel isolates contain various amino acid mutations and even a hypervariable region in their major antigenic domains, which might be the critical factors for the pathogenicity elevation and even change their antigenicity. The data presented in this report will enhance the current understanding of the epidemiology and genetic diversity of the novel genotype avian HEV in China and provide additional insight into the critical factors that determine the pathogenicity of it.
Collapse
Affiliation(s)
- Qi Su
- College of Veterinary Medicine, Shandong Agricultural University, Tai'an, Shandong, China.,Shandong Provincial Key Laboratory of Animal Biotechnology and Disease Control and Prevention, Tai'an, Shandong, China.,Shandong Provincial Engineering Technology Research Center of Animal Disease Control and Prevention, Tai'an, Shandong, China
| | - Yang Li
- China Animal Health and Epidemiology Center, Qingdao, Shandong, China
| | - Yawen Zhang
- College of Veterinary Medicine, Shandong Agricultural University, Tai'an, Shandong, China.,Shandong Provincial Key Laboratory of Animal Biotechnology and Disease Control and Prevention, Tai'an, Shandong, China.,Shandong Provincial Engineering Technology Research Center of Animal Disease Control and Prevention, Tai'an, Shandong, China
| | - Zhihui Zhang
- College of Veterinary Medicine, Shandong Agricultural University, Tai'an, Shandong, China.,Shandong Provincial Key Laboratory of Animal Biotechnology and Disease Control and Prevention, Tai'an, Shandong, China.,Shandong Provincial Engineering Technology Research Center of Animal Disease Control and Prevention, Tai'an, Shandong, China
| | - Fanfeng Meng
- College of Veterinary Medicine, Shandong Agricultural University, Tai'an, Shandong, China.,Shandong Provincial Key Laboratory of Animal Biotechnology and Disease Control and Prevention, Tai'an, Shandong, China.,Shandong Provincial Engineering Technology Research Center of Animal Disease Control and Prevention, Tai'an, Shandong, China
| | - Zhizhong Cui
- College of Veterinary Medicine, Shandong Agricultural University, Tai'an, Shandong, China.,Shandong Provincial Key Laboratory of Animal Biotechnology and Disease Control and Prevention, Tai'an, Shandong, China.,Shandong Provincial Engineering Technology Research Center of Animal Disease Control and Prevention, Tai'an, Shandong, China
| | - Shuang Chang
- College of Veterinary Medicine, Shandong Agricultural University, Tai'an, Shandong, China.,Shandong Provincial Key Laboratory of Animal Biotechnology and Disease Control and Prevention, Tai'an, Shandong, China.,Shandong Provincial Engineering Technology Research Center of Animal Disease Control and Prevention, Tai'an, Shandong, China
| | - Peng Zhao
- College of Veterinary Medicine, Shandong Agricultural University, Tai'an, Shandong, China.,Shandong Provincial Key Laboratory of Animal Biotechnology and Disease Control and Prevention, Tai'an, Shandong, China.,Shandong Provincial Engineering Technology Research Center of Animal Disease Control and Prevention, Tai'an, Shandong, China
| |
Collapse
|
31
|
Glitscher M, Himmelsbach K, Woytinek K, Johne R, Reuter A, Spiric J, Schwaben L, Grünweller A, Hildt E. Inhibition of Hepatitis E Virus Spread by the Natural Compound Silvestrol. Viruses 2018; 10:E301. [PMID: 29865243 PMCID: PMC6024817 DOI: 10.3390/v10060301] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2018] [Revised: 05/18/2018] [Accepted: 05/31/2018] [Indexed: 02/07/2023] Open
Abstract
Every year, there are about 20 Mio hepatitis E virus (HEV) infections and 60,000 deaths that are associated with HEV worldwide. At the present, there exists no specific therapy for HEV. The natural compound silvestrol has a potent antiviral effect against the (-)-strand RNA-virus Ebola virus, and also against the (+)-strand RNA viruses Corona-, Picorna-, and Zika virus. The inhibitory effect on virus spread is due to an inhibition of the DEAD-box RNA helicase eIF4A, which is required to unwind structured 5'-untranslated regions (UTRs). This leads to an impaired translation of viral RNA. The HEV (+)-strand RNA genome contains a 5'-capped, short 5'-UTR. This study aims to analyze the impact of silvestrol on the HEV life cycle. Persistently infected A549 cells were instrumental. This study identifies silvestrol as a potent inhibitor of the release of HEV infectious viral particles. This goes along with a strongly reduced HEV capsid protein translation, retention of viral RNA inside the cytoplasm, and without major cytotoxic effects. Interestingly, in parallel silvestrol affects the activity of the antiviral major vault protein (MVP) by translocation from the cytoplasm to the perinuclear membrane. These data further characterize the complex antiviral activity of silvestrol and show silvestrol's broad spectrum of function, since HEV is a virus without complex secondary structures in its genome, but it is still affected.
Collapse
Affiliation(s)
- Mirco Glitscher
- Department of Virology, Paul-Ehrlich-Institut, 63225 Langen, Germany.
| | | | - Kathrin Woytinek
- Department of Virology, Paul-Ehrlich-Institut, 63225 Langen, Germany.
| | - Reimar Johne
- Federal Institute for Risk Assessment, 10589 Berlin, Germany.
| | - Andreas Reuter
- Department of Allergology, Paul-Ehrlich-Institut, 63225 Langen, Germany.
| | - Jelena Spiric
- Department of Allergology, Paul-Ehrlich-Institut, 63225 Langen, Germany.
| | - Luisa Schwaben
- Department of Allergology, Paul-Ehrlich-Institut, 63225 Langen, Germany.
| | - Arnold Grünweller
- Institute of Pharmaceutical Chemistry, Philipps-Universität Marburg, 35037 Marburg, Germany.
| | - Eberhard Hildt
- Department of Virology, Paul-Ehrlich-Institut, 63225 Langen, Germany.
- German Center for Infection Research (DZIF), 38124 Braunschweig, Germany.
| |
Collapse
|
32
|
Hepatitis E in High-Income Countries: What Do We Know? And What Are the Knowledge Gaps? Viruses 2018; 10:v10060285. [PMID: 29799485 PMCID: PMC6024799 DOI: 10.3390/v10060285] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2018] [Revised: 05/16/2018] [Accepted: 05/23/2018] [Indexed: 12/11/2022] Open
Abstract
Hepatitis E virus (HEV) is a positive-strand RNA virus transmitted by the fecal–oral route. HEV genotypes 1 and 2 infect only humans and cause mainly waterborne outbreaks. HEV genotypes 3 and 4 are widely represented in the animal kingdom, and are mainly transmitted as a zoonosis. For the past 20 years, HEV infection has been considered an imported disease in developed countries, but now there is evidence that HEV is an underrecognized pathogen in high-income countries, and that the incidence of confirmed cases has been steadily increasing over the last decade. In this review, we describe current knowledge about the molecular biology of HEV, its clinical features, its main routes of transmission, and possible therapeutic strategies in developed countries.
Collapse
|
33
|
Harrison L, DiCaprio E. Hepatitis E Virus: An Emerging Foodborne Pathogen. FRONTIERS IN SUSTAINABLE FOOD SYSTEMS 2018. [DOI: 10.3389/fsufs.2018.00014] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
|
34
|
Abstract
Hepatitis E virus (HEV) infection can lead to acute and chronic hepatitis as well as to extrahepatic manifestations such as neurological and renal disease; it is the most common cause of acute viral hepatitis worldwide. Four genotypes are responsible for most infection in humans, of which HEV genotypes 1 and 2 are obligate human pathogens and HEV genotypes 3 and 4 are mostly zoonotic. Until quite recently, HEV was considered to be mainly responsible for epidemics of acute hepatitis in developing regions owing to contamination of drinking water supplies with human faeces. However, HEV is increasingly being recognized as endemic in some developed regions. In this setting, infections occur through zoonotic transmission or contaminated blood products and can cause chronic hepatitis in immunocompromised individuals. HEV infections can be diagnosed by measuring anti-HEV antibodies, HEV RNA or viral capsid antigen in blood or stool. Although an effective HEV vaccine exists, it is only licensed for use in China. Acute hepatitis E is usually self-limiting and does not require specific treatment. Management of immunocompromised individuals involves lowering the dose of immunosuppressive drugs and/or treatment with the antiviral agent ribavirin.
Collapse
|
35
|
Donnelly MC, Scobie L, Crossan CL, Dalton H, Hayes PC, Simpson KJ. Review article: hepatitis E-a concise review of virology, epidemiology, clinical presentation and therapy. Aliment Pharmacol Ther 2017; 46:126-141. [PMID: 28449246 DOI: 10.1111/apt.14109] [Citation(s) in RCA: 54] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/21/2016] [Revised: 12/21/2016] [Accepted: 03/30/2017] [Indexed: 12/13/2022]
Abstract
BACKGROUND Hepatitis E virus (HEV) is a leading cause of acute icteric hepatitis and acute liver failure in the developing world. During the last decade, there has been increasing recognition of autochthonous (locally acquired) HEV infection in developed countries. Chronic HEV infection is now recognised, and in transplant recipients this may lead to cirrhosis and organ failure. AIM To detail current understanding of the molecular biology of HEV, diagnostic and therapeutic strategies and propose future directions for basic science and clinical research. METHODS PubMed was searched for English language articles using the key words "hepatitis E", "viral hepatitis", "autochthonous infection", "antiviral therapy", "liver transplantation", "acute", "chronic", "HEV", "genotype", "transmission" "food-borne", "transfusion". Additional relevant publications were identified from article reference lists. RESULTS There has been increasing recognition of autochthonous HEV infection in Western countries, mainly associated with genotype 3. Chronic HEV infection has been recognised since 2008, and in transplant recipients this may lead to cirrhosis and organ failure. Modes of transmission include food-borne transmission, transfusion of blood products and solid organ transplantation. Ribavirin therapy is used to treat patients with chronic HEV infection, but new therapies are required as there have been reports of treatment failure with ribavirin. CONCLUSIONS Autochthonous HEV infection is a clinical issue with increasing burden. Future work should focus on increasing awareness of HEV infection in the developed world, emphasising the need for clinicians to have a low threshold for HEV testing, particularly in immunosuppressed patients. Patients at potential risk of chronic HEV infection must also be educated and given advice regarding prevention of infection.
Collapse
Affiliation(s)
- M C Donnelly
- Department of Hepatology and Scottish Liver Transplant Unit, University of Edinburgh, Royal Infirmary of Edinburgh, Edinburgh, UK
| | - L Scobie
- Department of Biological and Biomedical Sciences, Glasgow Caledonian University, Glasgow, UK
| | - C L Crossan
- Department of Biological and Biomedical Sciences, Glasgow Caledonian University, Glasgow, UK
| | - H Dalton
- Royal Cornwall Hospital Trust and European Centre for Environment and Human Health, University of Exeter, Truro, UK
| | - P C Hayes
- Department of Hepatology and Scottish Liver Transplant Unit, University of Edinburgh, Royal Infirmary of Edinburgh, Edinburgh, UK
| | - K J Simpson
- Department of Hepatology and Scottish Liver Transplant Unit, University of Edinburgh, Royal Infirmary of Edinburgh, Edinburgh, UK
| |
Collapse
|
36
|
Genotype-Specific Evolution of Hepatitis E Virus. J Virol 2017; 91:JVI.02241-16. [PMID: 28202767 DOI: 10.1128/jvi.02241-16] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2016] [Accepted: 01/31/2017] [Indexed: 12/20/2022] Open
Abstract
Hepatitis E virus (HEV) is the most common cause of acute viral hepatitis globally. HEV comprises four genotypes with different geographic distributions and host ranges. We utilize this natural case-control study for investigating the evolution of zoonotic viruses compared to single-host viruses, using 244 near-full-length HEV genomes. Genome-wide estimates of the ratio of nonsynonymous to synonymous evolutionary changes (dN/dS ratio) located a region of overlapping reading frames, which is subject to positive selection in genotypes 3 and 4. The open reading frames (ORFs) involved have functions related to host-pathogen interaction, so genotype-specific evolution of these regions may reflect their fitness. Bayesian inference of evolutionary rates shows that genotypes 3 and 4 have significantly higher rates than genotype 1 across all ORFs. Reconstruction of the phylogenies of zoonotic genotypes demonstrates significant intermingling of isolates between hosts. We speculate that the genotype-specific differences may result from cyclical adaptation to different hosts in genotypes 3 and 4.IMPORTANCE Hepatitis E virus (HEV) is increasingly recognized as a pathogen that affects both the developing and the developed world. While most often clinically mild, HEV can be severe or fatal in certain demographics, such as expectant mothers. Like many other viral pathogens, HEV has been classified into several distinct genotypes. We show that most of the HEV genome is evolutionarily constrained. One locus of positive selection is unusual in that it encodes two distinct protein products. We are the first to detect positive selection in this overlap region. Genotype 1, which infects humans only, appears to be evolving differently from genotypes 3 and 4, which infect multiple species, possibly because genotypes 3 and 4 are unable to achieve the same fitness due to repeated host jumps.
Collapse
|
37
|
Pelosi E, Clarke I. Hepatitis E: a complex and global disease. EMERGING HEALTH THREATS JOURNAL 2017. [DOI: 10.3402/ehtj.v1i0.7069] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Affiliation(s)
- E Pelosi
- Department of Microbiology and Virology, Health Protection Agency, Southeast Regional Laboratory, Southampton General Hospital, Southampton, UK; and
| | - I Clarke
- Department of Molecular Microbiology, Southampton Medical School, Southampton General Hospital, Southampton, UK
| |
Collapse
|
38
|
Nan Y, Zhang YJ. Molecular Biology and Infection of Hepatitis E Virus. Front Microbiol 2016; 7:1419. [PMID: 27656178 PMCID: PMC5013053 DOI: 10.3389/fmicb.2016.01419] [Citation(s) in RCA: 59] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2016] [Accepted: 08/26/2016] [Indexed: 12/13/2022] Open
Abstract
Hepatitis E virus (HEV) is a viral pathogen transmitted primarily via fecal-oral route. In humans, HEV mainly causes acute hepatitis and is responsible for large outbreaks of hepatitis across the world. The case fatality rate of HEV-induced hepatitis ranges from 0.5 to 3% in young adults and up to 30% in infected pregnant women. HEV strains infecting humans are classified into four genotypes. HEV strains from genotypes 3 and 4 are zoonotic, whereas those from genotypes 1 and 2 have no known animal reservoirs. Recently, notable progress has been accomplished for better understanding of HEV biology and infection, such as chronic HEV infection, in vitro cell culture system, quasi-enveloped HEV virions, functions of the HEV proteins, mechanism of HEV antagonizing host innate immunity, HEV pathogenesis and vaccine development. However, further investigation on the cross-species HEV infection, host tropism, vaccine efficacy, and HEV-specific antiviral strategy is still needed. This review mainly focuses on molecular biology and infection of HEV and offers perspective new insight of this enigmatic virus.
Collapse
Affiliation(s)
- Yuchen Nan
- Department of Preventive Veterinary Medicine, College of Veterinary Medicine, Northwest A&F UniversityYangling, China; Molecular Virology Laboratory, VA-MD College of Veterinary Medicine and Maryland Pathogen Research Institute, University of Maryland, College Park, College ParkMD, USA
| | - Yan-Jin Zhang
- Molecular Virology Laboratory, VA-MD College of Veterinary Medicine and Maryland Pathogen Research Institute, University of Maryland, College Park, College Park MD, USA
| |
Collapse
|
39
|
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.
Collapse
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.
| | | |
Collapse
|
40
|
Steele KE, Seth P, Catlin-Lebaron KMK, Schoneboom BA, Husain MM, Grieder F, Maheshwari RK. Tunicamycin Enhances Neuroinvasion and Encephalitis in Mice Infected with Venezuelan Equine Encephalitis Virus. Vet Pathol 2016; 43:904-13. [PMID: 17099147 DOI: 10.1354/vp.43-6-904] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Venezuelan equine encephalitis (VEE) viruses cause natural outbreaks in humans and horses and represent a significant biothreat agent. The effect of tunicamycin on the course of the disease in mice with VEE was investigated, and the combined effects of these agents was characterized. CD-1 mice given 2.5 μg of tunicamycin had > 1,000-fold more virus in the brain 48 hours after infection with the virulent VEE strain V3000 and >100-fold of the attenuated strain V3034 at all tested times than did untreated mice, indicating enhanced neuroinvasion. Tunicamycin did not alter the viremia profiles of these viruses nor the replication of V3000 in the brain itself. Tunicamycin alone caused ultrastructural blood-brain barrier damage, yet neuroinvasion by V3000 in treated mice appeared to occur via the olfactory system rather than the blood-brain barrier. Tunicamycin-treated, V3000-infected mice also exhibited earlier and more severe weight loss, neurological signs, neuronal infection, neuronal necrosis and apoptosis, and inflammation than untreated, V3000-infected mice. The mean survival time of tunicamycin-treated, V3000-infected mice was 7.3 days versus 9.9 days for untreated, V3000-infected mice. These studies imply that animals that ingest toxins similar to tunicamycin, including the agent of annual ryegrass toxicity in livestock, are conceivably at greater risk from infections by encephalitis viruses and that humans and horses exposed to agents acting similar to tunicamycin may be more susceptible to encephalitis caused by VEE viruses. The exact mechanism of tunicamycin-enhanced neuroinvasion by VEE viruses requires further study.
Collapse
Affiliation(s)
- K E Steele
- Department of Pathology, Uniformed Services University of the Health Sciences, 4301 Jones Bridge Road, Bethesda, MD 20814, USA
| | | | | | | | | | | | | |
Collapse
|
41
|
Identification of critical residues in Hepatitis E virus macro domain involved in its interaction with viral methyltransferase and ORF3 proteins. Sci Rep 2016; 6:25133. [PMID: 27113483 PMCID: PMC4844956 DOI: 10.1038/srep25133] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2015] [Accepted: 04/12/2016] [Indexed: 01/16/2023] Open
Abstract
Hepatitis E virus (HEV) is a major cause of hepatitis in normal and organ transplant individuals. HEV open reading frame-1 encodes a polypeptide comprising of the viral nonstructural proteins as well as domains of unknown function such as the macro domain (X-domain), V, DUF3729 and Y. The macro domain proteins are ubiquitously present from prokaryotes to human and in many positive-strand RNA viruses, playing important roles in multiple cellular processes. Towards understanding the function of the HEV macro domain, we characterized its interaction partners among other HEV encoded proteins. Here, we report that the HEV X-domain directly interacts with the viral methyltransferase and the ORF3 proteins. ORF3 association with the X-domain was mediated through two independent motifs, located within its N-terminal 35aa (amino acids) and C-terminal 63-123aa. Methyltransferase interaction domain was mapped to N-terminal 30-90aa. The X-domain interacted with both ORF3 and methyltransferase through its C-terminal region, involving 66th,67th isoleucine and 101st,102nd leucine, conserved across HEV genotypes. Furthermore, ORF3 and methyltransferase competed with each other for associating with the X-domain. These findings provide molecular understanding of the interaction between the HEV macro domain, methyltransferase and ORF3, suggesting an important role of the macro domain in the life cycle of HEV.
Collapse
|
42
|
Full coding hepatitis E virus genotype 3 genome amplification method. J Virol Methods 2016; 230:18-23. [PMID: 26784284 PMCID: PMC7172825 DOI: 10.1016/j.jviromet.2016.01.004] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2015] [Revised: 01/12/2016] [Accepted: 01/14/2016] [Indexed: 02/07/2023]
Abstract
A new amplification method for the complete HEV coding genome was described. HEV genome organization and function were reviewed. Polymorphic amino acids of each HEV genome region were analyzed in reference sequences. Complete coding HEV sequence of an immunocompromised patient with acute infection was analyzed.
Hepatitis E virus (HEV) genotype 3 produces zoonotic infection associated with the consumption of infected animals. HEV infections can become chronic in immunocompromised (IC) patients. The viral genome has three well defined open reading frames (ORF1, ORF2 and ORF3) within which various domains and functions have been described. This paper (i) describes a new method of complete sequencing of the HEV coding region through overlapping PCR systems, (ii) establishes a consensus sequence and polymorphic positions (PP) for each domain, and (iii) analyzes the complete coding sequence of an IC patient. With regard to the consensus, a high percentage of PP was observed in protease (PP = 19%) and the X domain (PP = 22%) within ORF1, the N-terminal region of the S domain (PP = 22%) in ORF2, and the P1 (PP = 35%) and P2 (PP = 25%) domains in ORF3. In contrast, the ORF1 Y, ORF2 S, ORF2 M and ORF3 D1 domains were conserved in the reference sequences (0.40, 1, 0.70 and 0% of PP, respectively). The sequence from the IC patient had more mutations in the RpRp (D1235G, Q1242R, S1454T, V1480I, I1502 V, K1511R, G1373 V, E1442D, V1693 M), the terminal ORF2 S- domain (F10L, S26T, G36S, S70P, A105 V, I113 V), the X domain (T938 M, T856 V, S898A) and the helicase (S1014N, S975T, Q1133 K).
Collapse
|
43
|
Zhang Y, Gong W, Zeng H, Wang L. Genetic Evolution of Hepatitis E Virus. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2016; 948:73-88. [PMID: 27738980 DOI: 10.1007/978-94-024-0942-0_5] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Comparative analysis of the genomic sequences of multiple hepatitis E virus (HEV) isolates has revealed extensive genomic diversity among them. Recently, a variety of genetically distinct HEV variants have also been isolated and identified from large numbers of animal species, including birds, rabbits, rats, ferrets, bats, cutthroat trout, and camels, among others. Furthermore, it has been reported that recombination in HEV genomes takes place in animals and in human patients. Also, chronic HEV infection in immunocompromised individuals has revealed the presence of viral strains carrying insertions from human genes. This paper reviews the current knowledge on the genomic variability and evolution of HEV.
Collapse
Affiliation(s)
- Yulin Zhang
- Department of Microbiology and Infectious Disease Center, School of Basic Medical Sciences, Peking University Health Science Center, 38 Xueyuan Road, Haidian District, Beijing, 100191, China
| | - Wanyun Gong
- Department of Microbiology and Infectious Disease Center, School of Basic Medical Sciences, Peking University Health Science Center, 38 Xueyuan Road, Haidian District, Beijing, 100191, China
| | - Hang Zeng
- Department of Microbiology and Infectious Disease Center, School of Basic Medical Sciences, Peking University Health Science Center, 38 Xueyuan Road, Haidian District, Beijing, 100191, China
| | - Ling Wang
- Department of Microbiology and Infectious Disease Center, School of Basic Medical Sciences, Peking University Health Science Center, 38 Xueyuan Road, Haidian District, Beijing, 100191, China.
| |
Collapse
|
44
|
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.
Collapse
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.
| |
Collapse
|
45
|
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.
Collapse
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.
| |
Collapse
|
46
|
The Hepatitis E virus intraviral interactome. Sci Rep 2015; 5:13872. [PMID: 26463011 PMCID: PMC4604457 DOI: 10.1038/srep13872] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2015] [Accepted: 08/07/2015] [Indexed: 12/19/2022] Open
Abstract
Hepatitis E virus (HEV) is an emerging virus causing epidemic acute hepatitis in developing countries as well as sporadic cases in industrialized countries. The life cycle of HEV is still poorly understood and the lack of efficient cell culture systems and animal models are the principal limitations for a detailed study of the viral replication cycle. Here we exhaustively examine all possible intraviral protein-protein interactions (PPIs) of HEV by systematic Yeast two-hybrid (Y2H) and LuMPIS screens, providing a basis for studying the function of these proteins in the viral replication cycle. Key PPIs correlate with the already published HEV 3D structure. Furthermore, we report 20 novel PPIs including the homodimerization of the RNA dependent RNA polymerase (RdRp), the self-interaction of the papain like protease, and ORF3 interactions with the papain-like protease and putative replicase components: RdRp, methylase and helicase. Furthermore, we determined the dissociation constant (Kd) of ORF3 interactions with the viral helicase, papain-like protease and methylase, which suggest a regulatory function for ORF3 in orchestrating the formation of the replicase complex. These interactions may represent new targets for antiviral drugs.
Collapse
|
47
|
van der Eijk AA, Pas SD, Cornelissen JJ, de Man RA. Hepatitis E virus infection in hematopoietic stem cell transplant recipients. Curr Opin Infect Dis 2015; 27:309-15. [PMID: 24977683 DOI: 10.1097/qco.0000000000000076] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
PURPOSE OF REVIEW Recipients of allogeneic stem cell transplantations are at risk of acquiring acute hepatitis E virus (HEV) infection, leading to chronicity. We review the incidence, sequela, extrahepatic manifestations, and treatment of hepatitis due to HEV infection in allogeneic hematopoietic stem cell transplantation (alloHSCT) recipients. RECENT FINDINGS HEV infection and progression to chronic HEV in alloHSCT recipients are recently described. Misdiagnosis of HEV in alloHSCT recipients occurs, with liver enzyme abnormalities often attributed to hepatic graft-versus-host disease or drug-induced liver injury. HEV infection may occur in HSCT donors and emphasizes the need for HEV screening not only after HSCT, but also in donors presenting with liver function disturbances. The discussion about HEV screening of blood products will continue. Extrahepatic manifestations of hepatitis E are described. SUMMARY HEV RNA screening in alloHSCT recipients with elevated liver enzymes is advised. Intervention strategies should be considered in cases of acute or chronic HEV infection. The first-line approach includes reduction of immunosuppressive medication. Oral ribavirin is in experienced hands a reasonable well tolerated treatment option, although the optimal dose, duration, and quantitative goals of ribavirin treatment are still unknown. Further studies are needed to improve our understanding of HEV, including extrahepatic manifestations and evaluation of therapeutic options.
Collapse
Affiliation(s)
- Annemiek A van der Eijk
- aDepartment of Viroscience bDepartment of Hematology cDepartment of Hepatogastroenterology, Erasmus Medical Center, Rotterdam, the Netherlands
| | | | | | | |
Collapse
|
48
|
Abstract
INTRODUCTION Hepatitis E virus (HEV) is one of the most common causes of acute viral hepatitis in the world with an estimated 20 million infections per year. Although the mortality rate is < 1% among the general population, pregnant women can have a fatality rate of up to 30%. Additionally, chronic hepatitis E has increasingly become a significant clinical problem in immunocompromised individuals. Effective antivirals against HEV are needed. AREAS COVERED This review article addresses the current state of knowledge of HEV infections with regard to animal and cell culture model systems that are important for antiviral discovery and testing, our current understanding of the molecular mechanisms of virus replication, our understanding of how each viral protein functions, and areas that can potentially be exploited as therapeutic targets. EXPERT OPINION Lack of an efficient cell culture system for HEV propagation, the limited knowledge of HEV lifecycle, and the inherent self-limiting infection within the normal populace make the development of new therapeutic agents against HEV challenging. There are many promising therapeutic targets, and the tools for identifying and testing potential antivirals are rapidly evolving. The development of effective therapeutics against HEV in immunocompromised and pregnant patient populations is warranted.
Collapse
Affiliation(s)
- Scott P Kenney
- Virginia Polytechnic Institute and State University (Virginia Tech), College of Veterinary Medicine, Center for Molecular Medicine and Infectious Diseases, Department of Biomedical Sciences and Pathobiology , CRC-Integrated Life Sciences Building (0913), 1981 Kraft Drive, Blacksburg, VA 24061-0913 , USA +1 540 231 6912 ; +1 540 231 3414 ;
| | | |
Collapse
|
49
|
Lessons from hepatitis E vaccine design. Curr Opin Virol 2015; 11:130-6. [PMID: 25913817 DOI: 10.1016/j.coviro.2015.04.003] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2014] [Revised: 04/01/2015] [Accepted: 04/06/2015] [Indexed: 12/29/2022]
Abstract
Acute hepatitis E is still a major public health issue, especially in developing countries, and hepatitis E virus (HEV) infection will likely only be preventable through prophylactic vaccines. In this review, we describe the lessons learnt from developing the first commercial hepatitis E vaccine (Hecolin), launched to market in China in 2012. The antigenicity and immunogenicity of VLP immunogens concomitant with the scalable Escherichia coli system and our large-scale clinical verification resulted in the success of our vaccine. The structures of the HEV capsid protein in complex with different antibodies provide important molecular insights into capsid assembly and antibody neutralization of the virus, providing a paradigm for B-cell epitope-based vaccine design.
Collapse
|
50
|
Feng Z, Hirai-Yuki A, McKnight KL, Lemon SM. Naked Viruses That Aren't Always Naked: Quasi-Enveloped Agents of Acute Hepatitis. Annu Rev Virol 2014; 1:539-60. [PMID: 26958733 DOI: 10.1146/annurev-virology-031413-085359] [Citation(s) in RCA: 109] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Historically, viruses were considered to be either enveloped or nonenveloped. However, recent work on hepatitis A virus and hepatitis E virus challenges this long-held tenet. Whereas these human pathogens are shed in feces as naked nonenveloped virions, recent studies indicate that both circulate in the blood completely masked in membranes during acute infection. These membrane-wrapped virions are as infectious as their naked counterparts, although they do not express a virally encoded protein on their surface, thus distinguishing them from conventional enveloped viruses. The absence of a viral fusion protein implies that these quasi-enveloped virions have unique mechanisms for entry into cells. Like true enveloped viruses, however, these phylogenetically distinct viruses usurp components of the host ESCRT system to hijack host cell membranes and noncytolytically exit infected cells. The membrane protects these viruses from neutralizing antibodies, facilitating dissemination within the host, whereas nonenveloped virions shed in feces are stable in the environment, allowing for epidemic transmission.
Collapse
Affiliation(s)
- Zongdi Feng
- Lineberger Comprehensive Cancer Center, Inflammatory Diseases Institute, and Departments of Medicine and Microbiology & Immunology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-7292;
| | - Asuka Hirai-Yuki
- Lineberger Comprehensive Cancer Center, Inflammatory Diseases Institute, and Departments of Medicine and Microbiology & Immunology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-7292;
| | - Kevin L McKnight
- Lineberger Comprehensive Cancer Center, Inflammatory Diseases Institute, and Departments of Medicine and Microbiology & Immunology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-7292;
| | - Stanley M Lemon
- Lineberger Comprehensive Cancer Center, Inflammatory Diseases Institute, and Departments of Medicine and Microbiology & Immunology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-7292;
| |
Collapse
|