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Zhang C, Freistaedter A, Schmelas C, Gunkel M, Dao Thi VL, Grimm D. An RNA Interference/Adeno-Associated Virus Vector-Based Combinatorial Gene Therapy Approach Against Hepatitis E Virus. Hepatol Commun 2021; 6:878-888. [PMID: 34719133 PMCID: PMC8948557 DOI: 10.1002/hep4.1842] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/15/2021] [Revised: 09/10/2021] [Accepted: 10/10/2021] [Indexed: 12/22/2022] Open
Abstract
Hepatitis E virus (HEV) is a major public health problem with limited therapeutic options. Here, we engineered adeno-associated viral vectors of serotype 6 (AAV6) to express short hairpin RNAs (shRNAs) against HEV transcripts with the prospect of down-regulating HEV replication in vivo. We designed 20 different shRNAs, targeting the genome of the HEV genotype 3 (GT3) Kernow-C1 p6 strain, for delivery upon AAV6 transduction. Using an original selectable HEV GT3 reporter replicon, we identified three shRNAs that efficiently down-regulated HEV replication. We further confirmed their inhibitory potency with full-length HEV infection. Seventy-two hours following transduction, HEV replication in both systems decreased by up to 95%. The three most potent inhibitory shRNAs identified were directed against the methyltransferase domain, the junction region between the open reading frames (ORFs), and the 3´ end of ORF2. Targeting all three regions by multiplexing the shRNAs further enhanced their inhibitory potency over a prolonged period of up to 21 days following transduction. Conclusion: Combining RNA interference and AAV vector-based gene therapy has great potential for suppressing HEV replication. Our strategy to target the viral RNA with multiplexed shRNAs should help to counteract viral escape through mutations. Considering the widely documented safety of AAV vector-based gene therapies, our approach is, in principle, amenable to clinical translation.
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Affiliation(s)
- Cindy Zhang
- Department of Infectious Diseases/Virology, Medical Faculty, Heidelberg University, Cluster of Excellence CellNetworks, BioQuant, Center for Integrative Infectious Diseases Research, Heidelberg, Germany.,Schaller Research group at Department of Infectious Diseases/Virology, Medical Faculty, Heidelberg University, Center for Integrative Infectious Diseases Research, Heidelberg, Germany.,German Center for Infection Research, Heidelberg, Germany
| | - Andrew Freistaedter
- Schaller Research group at Department of Infectious Diseases/Virology, Medical Faculty, Heidelberg University, Center for Integrative Infectious Diseases Research, Heidelberg, Germany
| | - Carolin Schmelas
- Department of Infectious Diseases/Virology, Medical Faculty, Heidelberg University, Cluster of Excellence CellNetworks, BioQuant, Center for Integrative Infectious Diseases Research, Heidelberg, Germany
| | - Manuel Gunkel
- High-Content Analysis of the Cell and Advanced Biological Screening Facility, BioQuant, Heidelberg University, Heidelberg, Germany
| | - Viet Loan Dao Thi
- Schaller Research group at Department of Infectious Diseases/Virology, Medical Faculty, Heidelberg University, Center for Integrative Infectious Diseases Research, Heidelberg, Germany.,German Center for Infection Research, Heidelberg, Germany
| | - Dirk Grimm
- Department of Infectious Diseases/Virology, Medical Faculty, Heidelberg University, Cluster of Excellence CellNetworks, BioQuant, Center for Integrative Infectious Diseases Research, Heidelberg, Germany.,German Center for Infection Research, Heidelberg, Germany.,German Center for Cardiovascular Research, Heidelberg, Germany
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Abstract
Hepatitis E virus (HEV) possesses many of the features of other positive-stranded RNA viruses but also adds HEV-specific nuances, making its virus-host interactions unique. Slow virus replication kinetics and fastidious growth conditions, coupled with the historical lack of an efficient cell culture system to propagate the virus, have left many gaps in our understanding of its structure and replication cycle. Recent advances in culturing selected strains of HEV and resolving the 3D structure of the viral capsid are filling in knowledge gaps, but HEV remains an extremely understudied pathogen. Many steps in the HEV life cycle and many aspects of HEV pathogenesis remain unknown, such as the host and viral factors that determine cross-species infection, the HEV-specific receptor(s) on host cells, what determines HEV chronicity and the ability to replicate in extrahepatic sites, and what regulates processing of the open reading frame 1 (ORF1) nonstructural polyprotein.
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Affiliation(s)
- Scott P Kenney
- Food Animal Health Research Program, The Ohio State University, Wooster, Ohio 44691
| | - Xiang-Jin Meng
- Department of Biomedical Sciences and Pathobiology, Virginia Polytechnic Institute and State University, Blacksburg, Virginia 24061
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Qureshi A, Tantray VG, Kirmani AR, Ahangar AG. A review on current status of antiviral siRNA. Rev Med Virol 2018; 28:e1976. [PMID: 29656441 PMCID: PMC7169094 DOI: 10.1002/rmv.1976] [Citation(s) in RCA: 68] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2017] [Revised: 01/18/2018] [Accepted: 02/12/2018] [Indexed: 01/12/2023]
Abstract
Viral diseases like influenza, AIDS, hepatitis, and Ebola cause severe epidemics worldwide. Along with their resistant strains, new pathogenic viruses continue to be discovered so creating an ongoing need for new antiviral treatments. RNA interference is a cellular gene‐silencing phenomenon in which sequence‐specific degradation of target mRNA is achieved by means of complementary short interfering RNA (siRNA) molecules. Short interfering RNA technology affords a potential tractable strategy to combat viral pathogenesis because siRNAs are specific, easy to design, and can be directed against multiple strains of a virus by targeting their conserved gene regions. In this review, we briefly summarize the current status of siRNA therapy for representative examples from different virus families. In addition, other aspects like their design, delivery, medical significance, bioinformatics resources, and limitations are also discussed.
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Affiliation(s)
- Abid Qureshi
- Biomedical Informatics Center, Sher-i-Kashmir Institute of Medical Sciences (SKIMS), Srinagar, India
| | - Vaqar Gani Tantray
- Biomedical Informatics Center, Sher-i-Kashmir Institute of Medical Sciences (SKIMS), Srinagar, India
| | - Altaf Rehman Kirmani
- Biomedical Informatics Center, Sher-i-Kashmir Institute of Medical Sciences (SKIMS), Srinagar, India
| | - Abdul Ghani Ahangar
- Biomedical Informatics Center, Sher-i-Kashmir Institute of Medical Sciences (SKIMS), Srinagar, India
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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.
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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
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Mahilkar S, Paingankar MS, Lole KS. Hepatitis E virus RNA-dependent RNA polymerase: RNA template specificities, recruitment and synthesis. J Gen Virol 2016; 97:2231-2242. [PMID: 27324050 DOI: 10.1099/jgv.0.000528] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Hepatitis E virus (HEV) is a positive-sense RNA virus and member of the genus Orthohepevirus in the family Hepeviridae. Although HEV RNA-dependent RNA polymerase (HEV-RdRp) plays an important role in the HEV life cycle, its template specificities are not completely understood. We expressed HEV-RdRp protein with His-tag in a bacterial system and analysed template specificities using different putative cis-regulatory elements in the HEV genome. The enzyme showed highest affinity for the 3' non-coding region (NCR), then for the 5'NCR and least for the putative subgenomic promoter (SgP). The enzyme could co-bind to 3'NCR and putative SgP templates together, as evident from the supershift in binding assay, indicating presence of different binding sites for these elements. Proteomic analysis revealed that the RNA elements share two common peptides for binding, while a third peptide, which is highly conserved across different HEV genotypes, is specific for 3'NCR. We propose that, during the early phases of replication, as negative sense antigenome copies accumulate at the replication site, they probably initiate promoter swapping from 3'NCR to SgP, to favour synthesis of subgenomic RNA and to prevent synthesis of genomic RNA. The conserved site for 3'NCR binding could be potential antiviral target and needs further evaluation.
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Affiliation(s)
- Shakuntala Mahilkar
- Hepatitis Division, National Institute of Virology, Microbial Containment Complex, Sus Road, Pashan, 411021 Pune, India
| | - Mandar S Paingankar
- Department of Zoology, Molecular Biology Research, Laboratory Savitribai Phule Pune University, 411007 Pune, India
| | - Kavita S Lole
- Hepatitis Division, National Institute of Virology, Microbial Containment Complex, Sus Road, Pashan, 411021 Pune, India
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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.
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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 ;
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The hepatitis E virus capsid C-terminal region is essential for the viral life cycle: implication for viral genome encapsidation and particle stabilization. J Virol 2013; 87:6031-6. [PMID: 23468481 DOI: 10.1128/jvi.00444-13] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
Although the C-terminal 52 amino acids (C52aa) of hepatitis E virus (HEV) capsid are not essential for morphology, the C52aa-encoding region is required for replication. Transfection of a C52aa knockdown mutant showed transient growth, and the earliest population included a majority of noninfectious (possibly empty) particles and a minority of infectious particles with C-terminal capsid degradation. Finally, the complete revertant was generated reproducibly. C52aa is essential for the viral life cycle, promoting accurate encapsidation and stabilizing encapsidated particles.
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Cao D, Meng XJ. Molecular biology and replication of hepatitis E virus. Emerg Microbes Infect 2012; 1:e17. [PMID: 26038426 PMCID: PMC3630916 DOI: 10.1038/emi.2012.7] [Citation(s) in RCA: 108] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2011] [Revised: 03/21/2012] [Accepted: 04/08/2012] [Indexed: 02/07/2023]
Abstract
Hepatitis E virus (HEV), a single-stranded, positive-sense RNA virus, is responsible for acute hepatitis E epidemics in many developing countries, and the virus is also endemic in some industrialized countries. Hepatitis E is a recognized zoonotic disease, and several animal species, including pigs, are potential reservoirs for HEV. The genome of HEV contains three open reading frames (ORFs). ORF1 encodes the nonstructural proteins, ORF2 encodes the capsid protein, and ORF3 encodes a small multifunctional protein. The ORF2 and ORF3 proteins are translated from a single, bicistronic mRNA. The coding sequences for these two ORFs overlap each other, but neither overlaps with ORF1. Whereas the mechanisms underlying HEV replication are poorly understood, the construction of infectious viral clones, the identification of cell lines that support HEV replication, and the development of small animal models have allowed for more detailed study of the virus. As result of these advances, recently, our understanding of viral entry, genomic replication and viral egress has improved. Furthermore, the determination of the T=1 and T=3 structure of HEV virus-like particles has furthered our understanding of the replication of HEV. This article reviews the latest developments in the molecular biology of HEV with an emphasis on the genomic organization, the expression and function of genes, and the structure and replication of HEV.
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Affiliation(s)
- Dianjun Cao
- Center for Molecular Medicine and Infectious Diseases, Department of Biomedical Sciences and Pathobiology, Virginia Polytechnic Institute and State University (Virginia Tech) , Blacksburg, VA 24061-0913, USA
| | - Xiang-Jin Meng
- Center for Molecular Medicine and Infectious Diseases, Department of Biomedical Sciences and Pathobiology, Virginia Polytechnic Institute and State University (Virginia Tech) , Blacksburg, VA 24061-0913, USA
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Shah PS, Schaffer DV. Antiviral RNAi: translating science towards therapeutic success. Pharm Res 2011; 28:2966-82. [PMID: 21826573 PMCID: PMC5012899 DOI: 10.1007/s11095-011-0549-8] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2011] [Accepted: 07/25/2011] [Indexed: 01/07/2023]
Abstract
Viruses continuously evolve to contend with an ever-changing environment that involves transmission between hosts and sometimes species, immune responses, and in some cases therapeutic interventions. Given the high mutation rate of viruses relative to the timescales of host evolution and drug development, novel drug classes that are readily screened and translated to the clinic are needed. RNA interference (RNAi)—a natural mechanism for specific degradation of target RNAs that is conserved from plants to invertebrates and vertebrates—can potentially be harnessed to yield therapies with extensive specificity, ease of design, and broad application. In this review, we discuss basic mechanisms of action and therapeutic applications of RNAi, including design considerations and areas for future development in the field.
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Affiliation(s)
- Priya S Shah
- Department of Chemical and Biolmolecular Engineering, University of California, Berkeley, California 94720, USA
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Liu T, Lei M, Jiao H, Du L, Cheng Y, Zhang D, Hao Y, Man C, Wang F. RNA interference induces effective inhibition of mRNA accumulation and protein expression of SHEV ORF3 gene in vitro. Curr Microbiol 2011; 62:1355-62. [PMID: 21225263 DOI: 10.1007/s00284-010-9863-3] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2010] [Accepted: 12/23/2010] [Indexed: 11/25/2022]
Abstract
RNA interference (RNAi) provides a powerful promising approach to inhibit viral infection specifically. To explore the possibility of using RNAi as a strategy against HEV infection, which is a serious public health problem in developing countries of Asia, Middle East, Africa, and in Mexico, after the fusion protein expression plasmids pEGFP-ORF3 which contain the EGFP reporter gene and SHEV ORF3 as silencing target, were constructed; EGFP-ORF3 fusion protein expressing HEK 293 cell lines were established; and four siRNAs targeting ORF3 gene were designed, synthesized, and used to transfect the stable cell lines. At 24, 48, and 72 h after transfection, flow cytometry, real-time quantitative PCR, and Western blot were used to assess the expression level of ORF3. The results demonstrated that specific siRNAs which are sequence dependant effectively inhibited mRNA accumulation and protein expression of SHEV ORF3 in HEK 293 cells. These findings provide useful information for the development of RNAi-based prophylaxis and therapy for SHEV infection.
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Affiliation(s)
- Tao Liu
- Hainan Key Lab of Tropical Animal Reproduction & Breeding and Epidemic Disease Research (Construction Period), Animal Genetic Engineering Key Lab of Haikou, College of Agriculture, Hainan University, Haidian Island, Haikou 570228, People's Republic of China
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