1
|
Wang Y, Fan L, Ye P, Wang Z, Liang C, Liu Q, Yang X, Long Z, Shi W, Zhou Y, Lin J, Yan H, Huang H, Liu L, Qian J. A novel transcription and replication-competent virus-like particles system modelling the Nipah virus life cycle. Emerg Microbes Infect 2024:2368217. [PMID: 38865205 DOI: 10.1080/22221751.2024.2368217] [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: 06/14/2024]
Abstract
AbstractNipah virus (NiV), a highly pathogenic Henipavirus in humans, has been responsible for annual outbreaks in recent years. Experiments revolving live NiV are highly restricted to biosafety level 4 (BSL-4) laboratories, which impedes NiV research. In this study, we developed a transcription and replication-competent NiV-like particles (trVLP-NiV) lacking N, P, and L genes. This trVLP-NiV exhibited the ability to infect and continuously passage in cells ectopically expressing N, P, and L proteins while maintaining stable genetic characteristics. Moreover, the trVLP-NiV displayed a favourable safety profile in hamsters. Using the system, we found the NiV nucleoprotein residues interacting with viral RNA backbone affected viral replication in opposite patterns. This engineered system was sensitive to well-established antiviral drugs, innate host antiviral factors, and neutralising antibodies. We then established a high-throughput screening platform utilizing the trVLP-NiV, leading to the identification of tunicamycin as a potential anti-NiV compound. Evidence showed that tunicamycin inhibited NiV replication by decreasing the infectivity of progeny virions. In conclusion, this trVLP-NiV system provided a convenient and versatile molecular tool for investigating NiV molecular biology and conducting antiviral drug screening under BSL-2 conditions. Its application will contribute to the development of medical countermeasures against NiV infections.
Collapse
Affiliation(s)
- Yulong Wang
- Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, China
| | - Linjin Fan
- Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, China
| | - Pengfei Ye
- Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, China
| | - Zequn Wang
- Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, China
| | - Chudan Liang
- Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, China
| | - Quan Liu
- Guangdong Key Laboratory of Animal Conservation and Resource Utilization, Guangdong Public Laboratory of Wild Animal Conservation and Utilization, Institute of Zoology, Guangdong Academy of Sciences, Guangzhou, China
| | - Xiaofeng Yang
- Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, China
| | - Zhenyu Long
- Institute of Infectious Diseases, Guangzhou Eighth people's Hospital, Guangzhou Medical University, Guangzhou, China
| | - Wendi Shi
- Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, China
| | - Yuandong Zhou
- Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, China
| | - Jingyan Lin
- Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, China
| | - Huijun Yan
- Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, China
| | - Hongxin Huang
- Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, China
| | - Linna Liu
- Institute of Infectious Diseases, Guangzhou Eighth people's Hospital, Guangzhou Medical University, Guangzhou, China
| | - Jun Qian
- Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, China
- School of Public Health (Shenzhen), Shenzhen Campus of Sun Yat-sen University, Shenzhen, China
- Shenzhen Key Laboratory of Pathogenic Microbes and Biosafety, Shenzhen, China
- Guangdong Provincial Highly Pathogenic Microorganism Science Data Center, Guangzhou, China
| |
Collapse
|
2
|
Xie SZ, Yao K, Li B, Peng C, Yang XL, Shi ZL. Development of a Měnglà virus minigenome and comparison of its polymerase complexes with those of other filoviruses. Virol Sin 2024:S1995-820X(24)00074-9. [PMID: 38782261 DOI: 10.1016/j.virs.2024.03.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2023] [Accepted: 03/25/2024] [Indexed: 05/25/2024] Open
Abstract
Ebola virus (EBOV) and Marburg virus (MARV), members of the Filoviridae family, are highly pathogenic and can cause hemorrhagic fevers, significantly impacting human society. Bats are considered reservoirs of these viruses because related filoviruses have been discovered in bats. However, due to the requirement for maximum containment laboratories when studying infectious viruses, the characterization of bat filoviruses often relies on pseudoviruses and minigenome systems. In this study, we used RACE technology to sequence the 3'-leader and 5'-trailer of Měnglà virus (MLAV) and constructed a minigenome. Similar to MARV, the transcription activities of the MLAV minigenome are independent of VP30. We further assessed the effects of polymorphisms at the 5' end on MLAV minigenome activity and identified certain mutations that decrease minigenome reporter efficiency, probably due to alterations in the RNA secondary structure. The reporter activity upon recombination of the 3'-leaders and 5'-trailers of MLAV, MARV, and EBOV with those of the homologous or heterologous minigenomes was compared and it was found that the polymerase complex and leader and trailer sequences exhibit intrinsic specificities. Additionally, we investigated whether the polymerase complex proteins from EBOV and MARV support MLAV minigenome RNA synthesis and found that the homologous system is more efficient than the heterologous system. Remdesivir efficiently inhibited MLAV as well as EBOV replication. In summary, this study provides new information on bat filoviruses and the minigenome will be a useful tool for high-throughput antiviral drug screening.
Collapse
Affiliation(s)
- Shi-Zhe Xie
- State Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, 430071, China; University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Ke Yao
- State Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, 430071, China; University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Bei Li
- State Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, 430071, China
| | - Cheng Peng
- State Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, 430071, China
| | - Xing-Lou Yang
- Yunnan Key Laboratory of Biodiversity Information, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, 650201, China; Hubei Jiangxia Laboratory, Wuhan, 430200, China.
| | - Zheng-Li Shi
- State Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, 430071, China.
| |
Collapse
|
3
|
Domènech-Eres R, Jaeckel M, Hadeler B, Lienemann T, Lutz T, Heinze C. A GFP-expressing minigenome of a chrysovirus replicating in fungi. Virology 2024; 591:109987. [PMID: 38219372 DOI: 10.1016/j.virol.2024.109987] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2023] [Revised: 12/11/2023] [Accepted: 01/05/2024] [Indexed: 01/16/2024]
Abstract
The Fusarium graminearum virus China 9 (FgV-ch9) is a member of the genus Betachrysovirus in the Chrysoviridae family and causes hypovirulence in its host, Fusarium graminearum, the causal agent of Fusarium head blight. Although insights into viral biology of FgV-ch9 have expanded in recent years, questions regarding the function of virus-encoded proteins, cis-acting elements, and virus transmission are yet to be answered. Therefore, we developed a tool for the establishment of an artificial 6th segment of FgV-ch9, which encodes a GFP gene flanked by the non-translated regions of FgV-ch9 segment 1. Subsequently, we have proved successful encapsidation of this artificial segment into virus particles as well as its horizontal transmission. Expression of GFP was further verified via immunoassay and life cell imaging. Thus far, we were able to establish for the first time a mini-replicon system for segmented dsRNA viruses replicating in fungi.
Collapse
Affiliation(s)
- Robert Domènech-Eres
- University of Hamburg, Institute of Plant Science and Microbiology, Molecular Phytopathology, Ohnhorststr. 18, 22609, Hamburg, Germany.
| | - Mareike Jaeckel
- University of Hamburg, Institute of Plant Science and Microbiology, Molecular Phytopathology, Ohnhorststr. 18, 22609, Hamburg, Germany.
| | - Birgit Hadeler
- University of Hamburg, Institute of Plant Science and Microbiology, Molecular Phytopathology, Ohnhorststr. 18, 22609, Hamburg, Germany.
| | - Tim Lienemann
- University of Hamburg, Institute of Plant Science and Microbiology, Molecular Phytopathology, Ohnhorststr. 18, 22609, Hamburg, Germany.
| | - Tobias Lutz
- University of Hamburg, Institute of Plant Science and Microbiology, Molecular Phytopathology, Ohnhorststr. 18, 22609, Hamburg, Germany.
| | - Cornelia Heinze
- University of Hamburg, Institute of Plant Science and Microbiology, Molecular Phytopathology, Ohnhorststr. 18, 22609, Hamburg, Germany.
| |
Collapse
|
4
|
O’Donnell KL, Callison J, Feldmann H, Hoenen T, Marzi A. Single-Dose Treatment With Vesicular Stomatitis Virus-Based Ebola Virus Vaccine Expressing Ebola Virus-Specific Artificial Micro-RNA Does Not Protect Mice From Lethal Disease. J Infect Dis 2023; 228:S677-S681. [PMID: 37186162 PMCID: PMC10651205 DOI: 10.1093/infdis/jiad121] [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: 03/15/2023] [Revised: 04/13/2023] [Accepted: 04/25/2023] [Indexed: 05/17/2023] Open
Abstract
Although significant progress has been made in the development of therapeutics against Ebola virus (EBOV), we sought to expand upon existing strategies and combine an RNA interference-based intervention with the approved vesicular stomatitis virus-based Ebola virus (VSV-EBOV) vaccine to conjointly treat and vaccinate patients during an outbreak. We constructed VSV-EBOV vectors expressing artificial micro-RNAs (amiRNAs) targeting sequences of EBOV proteins. In vitro experiments demonstrated a robust decrease in EBOV replication using a minigenome system and infectious virus. For in vivo evaluation, mouse-adapted EBOV-infected CD-1 mice were treated 24 hours after infection with a single dose of the VSV-EBOV amiRNA constructs. We observed no difference in disease progression or survival compared to the control-treated mice. In summary, while amiRNAs decrease viral replication in vitro, the effect is not sufficient to protect mice from lethal disease, and this therapeutic approach requires further optimization.
Collapse
Affiliation(s)
- Kyle L O’Donnell
- Laboratory of Virology, Division of Intramural Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, Montana
| | - Julie Callison
- Laboratory of Virology, Division of Intramural Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, Montana
| | - Heinz Feldmann
- Laboratory of Virology, Division of Intramural Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, Montana
| | - Thomas Hoenen
- Laboratory for Integrative Cell and Infection Biology, Institute of Molecular Virology and Cell Biology, Friedrich-Loeffler-Institut, Greifswald, Germany
| | - Andrea Marzi
- Laboratory of Virology, Division of Intramural Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, Montana
| |
Collapse
|
5
|
Hsu CJ, Chen CH, Chen WT, Liu PC, Chang TY, Lin MH, Chen CC, Chen HY, Huang CH, Cheng YH, Sun JR. Development of an EBOV MiniG plus system as an advanced tool for anti-Ebola virus drug screening. Heliyon 2023; 9:e22138. [PMID: 38045158 PMCID: PMC10692823 DOI: 10.1016/j.heliyon.2023.e22138] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2023] [Revised: 10/21/2023] [Accepted: 11/05/2023] [Indexed: 12/05/2023] Open
Abstract
The incidence of zoonotic diseases, such as coronavirus disease 2019 and Ebola virus disease, is increasing worldwide. However, drug and vaccine development for zoonotic diseases has been hampered because the experiments involving live viruses are limited to high-containment laboratories. The Ebola virus minigenome system enables researchers to study the Ebola virus under BSL-2 conditions. Here, we found that the addition of the nucleocapsid protein of human coronaviruses, such as severe acute respiratory syndrome coronavirus 2, can increase the ratio of green fluorescent protein-positive cells by 1.5-2 folds in the Ebola virus minigenome system. Further analysis showed that the nucleocapsid protein acts as an activator of the Ebola virus minigenome system. Here, we developed an EBOV MiniG Plus system based on the Ebola virus minigenome system by adding the SARS-CoV-2 nucleocapsid protein. By evaluating the antiviral effect of remdesivir and rupintrivir, we demonstrated that compared to that of the traditional Ebola virus minigenome system, significant concentration-dependent activity was observed in the EBOV MiniG Plus system. Taken together, these results demonstrate the utility of adding nucleocapsid protein to the Ebola virus minigenome system to create a powerful platform for screening antiviral drugs against the Ebola virus.
Collapse
Affiliation(s)
- Chi-Ju Hsu
- Institute of Preventive Medicine, National Defense Medical Center, Taipei, Taiwan
- Graduate Institute of Medical Science, National Defense Medical Center, Taipei, Taiwan
| | - Cheng-Hsiu Chen
- Institute of Preventive Medicine, National Defense Medical Center, Taipei, Taiwan
- Graduate Institute of Medical Science, National Defense Medical Center, Taipei, Taiwan
| | - Wen-Ting Chen
- Institute of Preventive Medicine, National Defense Medical Center, Taipei, Taiwan
| | - Ping-Cheng Liu
- Institute of Preventive Medicine, National Defense Medical Center, Taipei, Taiwan
- Graduate Institute of Applied Science and Technology, National Taiwan University of Science and Technology, Taiwan
| | - Tein-Yao Chang
- Institute of Preventive Medicine, National Defense Medical Center, Taipei, Taiwan
- Department of Pathology and Graduate Institute of Pathology and Parasitology, Tri-Service General Hospital, National Defense Medical Center, Taiwan
| | - Meng-He Lin
- Institute of Preventive Medicine, National Defense Medical Center, Taipei, Taiwan
| | - Cheng-Cheung Chen
- Institute of Preventive Medicine, National Defense Medical Center, Taipei, Taiwan
- Graduate Institute of Medical Science, National Defense Medical Center, Taipei, Taiwan
| | - Hsing-Yu Chen
- Department of Medical Techniques, Taipei City Hospital Ren-Ai Branch, Taiwan
| | - Chih-Heng Huang
- Institute of Preventive Medicine, National Defense Medical Center, Taipei, Taiwan
- Graduate Institute of Medical Science, National Defense Medical Center, Taipei, Taiwan
| | - Yun-Hsiang Cheng
- Institute of Preventive Medicine, National Defense Medical Center, Taipei, Taiwan
- Department of Physiology and Biophysics, Graduate Institute of Physiology, National Defense Medical Center, Taiwan
| | - Jun-Ren Sun
- Institute of Preventive Medicine, National Defense Medical Center, Taipei, Taiwan
- Graduate Institute of Medical Science, National Defense Medical Center, Taipei, Taiwan
- Department of Physiology and Biophysics, Graduate Institute of Physiology, National Defense Medical Center, Taiwan
- Division of Infectious Diseases and Tropical Medicine, Department of Internal Medicine, Tri-Service General Hospital, National Defense Medical Center, Taiwan
| |
Collapse
|
6
|
Sion E, Ab-Rahim S, Muhamad M. Trends on Human Norovirus Virus-like Particles (HuNoV-VLPs) and Strategies for the Construction of Infectious Viral Clones toward In Vitro Replication. Life (Basel) 2023; 13:1447. [PMID: 37511822 PMCID: PMC10381778 DOI: 10.3390/life13071447] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2023] [Revised: 06/07/2023] [Accepted: 06/10/2023] [Indexed: 07/30/2023] Open
Abstract
Most acute gastroenteritis (AGE) outbreaks and sporadic cases in developing countries are attributable to infection by human norovirus (HuNoV), the enteric virus mainly transmitted via fecal-contaminated water. However, it has been challenging to study HuNoV due to the lack of suitable systems to cultivate and replicate the virus, hindering the development of treatments and vaccines. Researchers have been using virus-like particles (VLPs) and infectious viral clones to overcome this challenge as alternatives to fresh virus isolates in various in vitro and ex vivo models. VLPs are multiprotein structures that mimic the wild-type virus but cannot replicate in host cells due to the lack of genetic materials for replication, limiting downstream analysis of the virus life cycle and pathogenesis. The development of in vitro cloning systems has shown promise for HuNoV replication studies. This review discusses the approaches for constructing HuNoV-VLPs and infectious viral clones, the techniques involved, and the challenges faced. It also highlights the relationship between viral genes and their protein products and provides a perspective on technical considerations for producing efficient HuNoV-VLPs and infectious viral clones, which could substitute for native human noroviruses in future studies.
Collapse
Affiliation(s)
- Emilly Sion
- Department of Biochemistry and Molecular Medicine, Faculty of Medicine, Universiti Teknologi MARA, Selangor Branch, Sungai Buloh Campus, Sungai Buloh 47000, Selangor, Malaysia
| | - Sharaniza Ab-Rahim
- Department of Biochemistry and Molecular Medicine, Faculty of Medicine, Universiti Teknologi MARA, Selangor Branch, Sungai Buloh Campus, Sungai Buloh 47000, Selangor, Malaysia
| | - Mudiana Muhamad
- Department of Biochemistry and Molecular Medicine, Faculty of Medicine, Universiti Teknologi MARA, Selangor Branch, Sungai Buloh Campus, Sungai Buloh 47000, Selangor, Malaysia
| |
Collapse
|
7
|
Zimmermann L, Chlanda P. Cryo-electron tomography of viral infection - from applications to biosafety. Curr Opin Virol 2023; 61:101338. [PMID: 37348443 DOI: 10.1016/j.coviro.2023.101338] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2022] [Revised: 04/25/2023] [Accepted: 05/28/2023] [Indexed: 06/24/2023]
Abstract
Cellular cryo-electron tomography (cryo-ET) offers 3D snapshots at molecular resolution capturing pivotal steps during viral infection. However, tomogram quality depends on the vitrification level of the sample and its thickness. In addition, mandatory inactivation protocols to assure biosafety when handling highly pathogenic viruses during cryo-ET can compromise sample preservation. Here, we focus on different strategies applied in cryo-ET and discuss their advantages and limitations with reference to severe acute respiratory syndrome coronavirus 2 studies. We highlight the importance of virus-like particle (VLP) and replicon systems to study virus assembly and replication in a cellular context without inactivation protocols. We discuss the application of chemical fixation and different irradiation methods in cryo-ET sample preparation and acquisition workflows.
Collapse
Affiliation(s)
- Liv Zimmermann
- Schaller Research Groups, Department of Infectious Diseases, Virology, Heidelberg University Hospital, 69120 Heidelberg, Germany
| | - Petr Chlanda
- Schaller Research Groups, Department of Infectious Diseases, Virology, Heidelberg University Hospital, 69120 Heidelberg, Germany.
| |
Collapse
|
8
|
van der Meulen K, Smets G, Rüdelsheim P. Viral Replicon Systems and Their Biosafety Aspects. APPLIED BIOSAFETY 2023; 28:102-122. [PMID: 37342518 PMCID: PMC10278005 DOI: 10.1089/apb.2022.0037] [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: 06/23/2023]
Abstract
Introduction Viral RNA replicons are self-amplifying RNA molecules generated by deleting genetic information of one or multiple structural proteins of wild-type viruses. Remaining viral RNA is used as such (naked replicon) or packaged into a viral replicon particle (VRP), whereby missing genes or proteins are supplied via production cells. Since replicons mostly originate from pathogenic wild-type viruses, careful risk consideration is crucial. Methods A literature review was performed compiling information on potential biosafety risks of replicons originating from positive- and negative-sense single-stranded RNA viruses (except retroviruses). Results For naked replicons, risk considerations included genome integration, persistence in host cells, generation of virus-like vesicles, and off-target effects. For VRP, the main risk consideration was formation of primary replication competent virus (RCV) as a result of recombination or complementation. To limit the risks, mostly measures aiming at reducing the likelihood of RCV formation have been described. Also, modifying viral proteins in such a way that they do not exhibit hazardous characteristics in the unlikely event of RCV formation has been reported. Discussion and Conclusion Despite multiple approaches developed to reduce the likelihood of RCV formation, scientific uncertainty remains on the actual contribution of the measures and on limitations to test their effectiveness. In contrast, even though effectiveness of each individual measure is unclear, using multiple measures on different aspects of the system may create a solid barrier. Risk considerations identified in the current study can also be used to support risk group assignment of replicon constructs based on a purely synthetic design.
Collapse
|
9
|
Pseudotyped Viruses for Marburgvirus and Ebolavirus. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2023; 1407:105-132. [PMID: 36920694 DOI: 10.1007/978-981-99-0113-5_6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/16/2023]
Abstract
Marburg virus (MARV) and Ebola virus (EBOV) of the Filoviridae family are the most lethal viruses in terms of mortality rate. However, the development of antiviral treatment is hampered by the requirement for biosafety level-4 (BSL-4) containment. The establishment of BSL-2 pseudotyped viruses can provide important tools for the study of filoviruses. This chapter summarizes general information on the filoviruses and then focuses on the construction of replication-deficient pseudotyped MARV and EBOV (e.g., lentivirus system and vesicular stomatitis virus system). It also details the potential applications of the pseudotyped viruses, including neutralization antibody detection, the study of infection mechanisms, the evaluation of antibody-dependent enhancement, virus entry inhibitor screening, and glycoprotein mutation analysis.
Collapse
|
10
|
Afowowe TO, Sakurai Y, Urata S, Zadeh VR, Yasuda J. Topoisomerase II as a Novel Antiviral Target against Panarenaviral Diseases. Viruses 2022; 15:105. [PMID: 36680145 PMCID: PMC9866940 DOI: 10.3390/v15010105] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2022] [Revised: 12/23/2022] [Accepted: 12/28/2022] [Indexed: 01/01/2023] Open
Abstract
Although many arenaviruses cause severe diseases with high fatality rates each year, treatment options are limited to off-label use of ribavirin, and a Food and Drug Administration (FDA)-approved vaccine is not available. To identify novel therapeutic candidates against arenaviral diseases, an RNA polymerase I-driven minigenome (MG) expression system for Lassa virus (LASV) was developed and optimized for high-throughput screening (HTS). Using this system, we screened 2595 FDA-approved compounds for inhibitors of LASV genome replication and identified multiple compounds including pixantrone maleate, a topoisomerase II inhibitor, as hits. Other tested topoisomerase II inhibitors also suppressed LASV MG activity. These topoisomerase II inhibitors also inhibited Junin virus (JUNV) MG activity and effectively limited infection by the JUNV Candid #1 strain, and siRNA knockdown of both topoisomerases (IIα and IIβ) restricted JUNV replication. These results suggest that topoisomerases II regulate arenavirus replication and can serve as molecular targets for panarenaviral replication inhibitors.
Collapse
Affiliation(s)
- Tosin Oladipo Afowowe
- Department of Emerging Infectious Diseases, Institute of Tropical Medicine (NEKKEN), Nagasaki University, Nagasaki 852-8523, Japan
- Program for Nurturing Global Leaders in Tropical and Emerging Communicable Diseases, Graduate School of Biomedical Sciences, Nagasaki University, Nagasaki 852-8523, Japan
| | - Yasuteru Sakurai
- Department of Emerging Infectious Diseases, Institute of Tropical Medicine (NEKKEN), Nagasaki University, Nagasaki 852-8523, Japan
- National Research Center for the Control and Prevention of Infectious Diseases (CCPID), Nagasaki University, Nagasaki 852-8523, Japan
| | - Shuzo Urata
- National Research Center for the Control and Prevention of Infectious Diseases (CCPID), Nagasaki University, Nagasaki 852-8523, Japan
| | - Vahid Rajabali Zadeh
- Department of Emerging Infectious Diseases, Institute of Tropical Medicine (NEKKEN), Nagasaki University, Nagasaki 852-8523, Japan
| | - Jiro Yasuda
- Department of Emerging Infectious Diseases, Institute of Tropical Medicine (NEKKEN), Nagasaki University, Nagasaki 852-8523, Japan
- Program for Nurturing Global Leaders in Tropical and Emerging Communicable Diseases, Graduate School of Biomedical Sciences, Nagasaki University, Nagasaki 852-8523, Japan
- National Research Center for the Control and Prevention of Infectious Diseases (CCPID), Nagasaki University, Nagasaki 852-8523, Japan
| |
Collapse
|
11
|
Abstract
Ebola virus (EBOV) VP30 regulates viral genome transcription and replication by switching its phosphorylation status. However, the importance of VP30 phosphorylation and dephosphorylation in other viral replication processes such as nucleocapsid and virion assembly is unclear. Interestingly, VP30 is predominantly dephosphorylated by cellular phosphatases in viral inclusions, while it is phosphorylated in the released virions. Thus, uncertainties regarding how VP30 phosphorylation in nucleocapsids is achieved and whether VP30 phosphorylation provides any advantages in later steps in viral replication have arisen. In the present study, to characterize the roles of VP30 phosphorylation in nucleocapsid formation, we used electron microscopic analyses and live cell imaging systems. We identified VP30 localized to the surface of protrusions surrounding nucleoprotein (NP)-forming helical structures in the nucleocapsid, suggesting the involvement in assembly and transport of nucleocapsids. Interestingly, VP30 phosphorylation facilitated its association with nucleocapsid-like structures (NCLSs). On the contrary, VP30 phosphorylation does not influence the transport characteristics and NCLS number leaving from and coming back into viral inclusions, indicating that the phosphorylation status of VP30 is not a prerequisite for NCLS departure. Moreover, the phosphorylation status of VP30 did not cause major differences in nucleocapsid transport in authentic EBOV-infected cells. In the following budding step, the association of VP30 and its phosphorylation status did not influence the budding efficiency of virus-like particles. Taken together, it is plausible that EBOV may utilize the phosphorylation of VP30 for its selective association with nucleocapsids, without affecting nucleocapsid transport and virion budding processes. IMPORTANCE Ebola virus (EBOV) causes severe fevers with unusually high case fatality rates. The nucleocapsid provides the template for viral genome transcription and replication. Thus, understanding the regulatory mechanism behind its formation is important for the development of novel therapeutic approaches. Previously, we established a live-cell imaging system based on the ectopic expression of viral fluorescent fusion proteins, allowing the visualization and characterization of intracytoplasmic transport of nucleocapsid-like structures. EBOV VP30 is an essential transcriptional factor for viral genome synthesis, and, although its role in viral genome transcription and replication is well understood, the functional importance of VP30 phosphorylation in assembly of nucleocapsids is still unclear. Our work determines the localization of VP30 at the surface of ruffled nucleocapsids, which differs from the localization of polymerase in EBOV-infected cells. This study sheds light on the novel role of VP30 phosphorylation in nucleocapsid assembly, which is an important prerequisite for virion formation.
Collapse
|
12
|
Vanmechelen B, Stroobants J, Chiu W, Naesens L, Schepers J, Vermeire K, Maes P. Development and optimization of biologically contained Marburg virus for high-throughput antiviral screening. Antiviral Res 2022; 207:105426. [DOI: 10.1016/j.antiviral.2022.105426] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2022] [Revised: 09/17/2022] [Accepted: 09/24/2022] [Indexed: 11/27/2022]
|
13
|
Comparison of Crimean-Congo Hemorrhagic Fever Virus and Aigai Virus in Life Cycle Modeling Systems Reveals a Difference in L Protein Activity. J Virol 2022; 96:e0059922. [PMID: 35695578 PMCID: PMC9278617 DOI: 10.1128/jvi.00599-22] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Crimean-Congo hemorrhagic fever virus (CCHFV) is a tick-borne orthonairovirus that causes a severe, often fatal, hemorrhagic disease throughout Africa, Asia, and Southeast Europe. A wide variety of strains are circulating in the field which broadly correlate to their geographic distribution. The viral determinants of pathogenicity remain unclear, as does the contribution of strain-specific differences to pathology. Aigai virus (AIGV) is a closely related virus (formally designated CCHFV genotype VI, Europe II, or AP92-like virus), which has been proposed to be less virulent than CCHFV. However, the molecular details leading to potential differences in virulence are unknown. To explore if differences exist, life cycle modeling systems, including both a minigenome and a transcriptionally competent virus-like particle assay, were developed for AIGV to allow the comparison with the CCHFV reference IbAr10200 strain. Using this approach, we could demonstrate that AIGV exhibits lower viral gene expression than the reference strain of CCHFV. Subsequent systematic exchange of viral components revealed that the L protein is responsible for the observed differences in gene expression and that the interferon (IFN) antagonistic activity of the ovarian tumor-type protease domain is not responsible for this effect. IMPORTANCE Crimean-Congo hemorrhagic fever virus (CCHFV) is the cause of severe hemorrhagic disease, which is often fatal. Present throughout Africa, Asia, and Southeast Europe, a diverse number of viral genotypes exist. However, the viral determinants of pathogenicity remain unclear. It has been proposed that the closely related Aigai virus (AIGV) may be a less virulent virus. Here, using newly developed and improved life cycle modeling systems we have examined potential differences between the CCHFV reference strain, IbAr10200, and AIGV. Using this approach, we identified lower viral gene expression driven by the AIGV viral polymerase as a major difference which may be indicative of lower virulence.
Collapse
|
14
|
Vanmechelen B, Stroobants J, Chiu W, Schepers J, Marchand A, Chaltin P, Vermeire K, Maes P. Identification of novel Ebola virus inhibitors using biologically contained virus. Antiviral Res 2022; 200:105294. [PMID: 35337896 DOI: 10.1016/j.antiviral.2022.105294] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2021] [Revised: 03/09/2022] [Accepted: 03/20/2022] [Indexed: 12/13/2022]
Abstract
Despite recent advancements in the development of vaccines and monoclonal antibody therapies for Ebola virus disease, treatment options remain limited. Moreover, management and containment of Ebola virus outbreaks is often hindered by the remote nature of the locations in which the outbreaks originate. Small-molecule compounds offer the advantage of being relatively cheap and easy to produce, transport and store, making them an interesting modality for the development of novel therapeutics against Ebola virus disease. Furthermore, the repurposing of small-molecule compounds, previously developed for alternative applications, can aid in reducing the time needed to bring potential therapeutics from bench to bedside. For this purpose, the Medicines for Malaria Venture provides collections of previously developed small-molecule compounds for screening against other infectious diseases. In this study, we used biologically contained Ebola virus to screen over 4,200 small-molecule drugs and drug-like compounds provided by the Medicines for Malaria Venture (i.e., the Pandemic Response Box and the COVID Box) and the Centre for Drug Design and Discovery (CD3, KU Leuven, Belgium). In addition to confirming known Ebola virus inhibitors, illustrating the validity of our screening assays, we identified eight novel selective Ebola virus inhibitors. Although the inhibitory potential of these compounds remains to be validated in vivo, they represent interesting compounds for the study of potential interventions against Ebola virus disease and might serve as a basis for the development of new therapeutics.
Collapse
Affiliation(s)
- Bert Vanmechelen
- KU Leuven, Department of Microbiology, Immunology and Transplantation, Rega Institute, Laboratory of Clinical and Epidemiological Virology, Leuven, Belgium
| | - Joren Stroobants
- KU Leuven, Department of Microbiology, Immunology and Transplantation, Rega Institute, Laboratory of Virology and Chemotherapy, Leuven, Belgium
| | - Winston Chiu
- KU Leuven, Department of Microbiology, Immunology and Transplantation, Rega Institute, Laboratory of Virology and Chemotherapy, Leuven, Belgium
| | - Joost Schepers
- KU Leuven, Department of Microbiology, Immunology and Transplantation, Rega Institute, Laboratory of Virology and Chemotherapy, Leuven, Belgium
| | - Arnaud Marchand
- CISTIM Leuven vzw, Gaston Geenslaan 2, 3000, Leuven, Belgium
| | - Patrick Chaltin
- CISTIM Leuven vzw, Gaston Geenslaan 2, 3000, Leuven, Belgium; Centre for Drug Design and Discovery (CD3), KU Leuven, Gaston Geenslaan 2, 3000, Leuven, Belgium
| | - Kurt Vermeire
- KU Leuven, Department of Microbiology, Immunology and Transplantation, Rega Institute, Laboratory of Virology and Chemotherapy, Leuven, Belgium
| | - Piet Maes
- KU Leuven, Department of Microbiology, Immunology and Transplantation, Rega Institute, Laboratory of Clinical and Epidemiological Virology, Leuven, Belgium.
| |
Collapse
|
15
|
Hirano M, Sakurai Y, Urata S, Kurosaki Y, Yasuda J, Yoshii K. A screen of FDA-approved drugs with minigenome identified tigecycline as an antiviral targeting nucleoprotein of Crimean-Congo hemorrhagic fever virus. Antiviral Res 2022; 200:105276. [DOI: 10.1016/j.antiviral.2022.105276] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2021] [Revised: 02/07/2022] [Accepted: 03/03/2022] [Indexed: 01/10/2023]
|
16
|
Li N, Zhang Y, Yao L, Shi Y, Zhao Q, Huang B, Sun Y. A Recombinant Porcine Reproductive and Respiratory Syndrome Virus Stably Expressing DsRed Protein Based on Bacterial Artificial Chromosome System. Front Microbiol 2022; 13:839845. [PMID: 35126342 PMCID: PMC8814527 DOI: 10.3389/fmicb.2022.839845] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2021] [Accepted: 01/03/2022] [Indexed: 11/13/2022] Open
Abstract
Recombinant viruses possessing reporter proteins as tools are widely applied in investigating viral biology because of the convenience for observation. Previously, we generated a recombinant pathogenic porcine reproductive and respiratory syndrome virus (PRRSV) with enhanced green fluorescent protein (EGFP) reporter for monitoring virus spread and screening of neutralizing antibodies. PRRSV with different kinds of reporters can support more application scenarios. Here, we described a new genetically stable infectious clones of a highly pathogenic PRRSV (HP-PRRSV) harboring the DsRed (a red fluorescent protein isolated from the coral Discosoma) gene. In the recombinant infectious clone, the transcription regulatory sequence 2 (TRS2) of PRRSV was inserted between the open reading frame 7 (ORF7) and 3′UTR to drive the transcription of DsRed gene, which makes it a separate transcription unit in the viral genome. Using the bacterial artificial chromosome (BAC) system and cytomegalovirus (CMV) promoter, the recombinant HP-PRRSV with the DsRed insertion was successfully rescued and showed similar growth and replication patterns compared with the wild-type virus in the MARC-145 cells. In addition, the DsRed protein was stably expressed in the recombinant virus for at least 10 passages with consistent fluorescence intensity and density. Using the recombinant HP-PRRSV with DsRed protein, the virus tracking in MARC-145 was observed by live-cell imaging. Meanwhile, quantification of the DsRed fluorescence positive cells by flow cytometry provides an alternative to standard methods for testing the level of PRRSV infection. This recombinant PRRSV with DsRed fluorescence protein expression could be a useful tool for fundamental research on the viral biology and shows the new design for stable expression of foreign genes in PRRSV.
Collapse
Affiliation(s)
- Na Li
- Key Laboratory of Ecological Security, Collaborative Innovation Centre of Water Security for Water Source Region of Mid-line of South-to-North Diversion Project of Henan Province, Henan Provincial Engineering and Technology Center of Health Products for Livestock and Poultry, School of Life Sciences and Agricultural Engineering, Nanyang Normal University, Nanyang, China
| | - Yiyi Zhang
- Key Laboratory of Ecological Security, Collaborative Innovation Centre of Water Security for Water Source Region of Mid-line of South-to-North Diversion Project of Henan Province, Henan Provincial Engineering and Technology Center of Health Products for Livestock and Poultry, School of Life Sciences and Agricultural Engineering, Nanyang Normal University, Nanyang, China
| | - Lunguang Yao
- Key Laboratory of Ecological Security, Collaborative Innovation Centre of Water Security for Water Source Region of Mid-line of South-to-North Diversion Project of Henan Province, Henan Provincial Engineering and Technology Center of Health Products for Livestock and Poultry, School of Life Sciences and Agricultural Engineering, Nanyang Normal University, Nanyang, China
| | - Yunpeng Shi
- Shijiazhuang Customs (Huanghua Port), Cangzhou, China
| | - Qin Zhao
- College of Veterinary Medicine, Northwest A&F University, Yangling, China
| | - Baicheng Huang
- National Research Center for Veterinary Medicine, Luoyang, China
- *Correspondence: Baicheng Huang,
| | - Yani Sun
- College of Veterinary Medicine, Northwest A&F University, Yangling, China
- Yani Sun,
| |
Collapse
|
17
|
Ren F, Shen S, Wang Q, Wei G, Huang C, Wang H, Ning YJ, Zhang DY, Deng F. Recent Advances in Bunyavirus Reverse Genetics Research: Systems Development, Applications, and Future Perspectives. Front Microbiol 2021; 12:771934. [PMID: 34950119 PMCID: PMC8689132 DOI: 10.3389/fmicb.2021.771934] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2021] [Accepted: 11/03/2021] [Indexed: 12/25/2022] Open
Abstract
Bunyaviruses are members of the Bunyavirales order, which is the largest group of RNA viruses, comprising 12 families, including a large group of emerging and re-emerging viruses. These viruses can infect a wide variety of species worldwide, such as arthropods, protozoans, plants, animals, and humans, and pose substantial threats to the public. In view of the fact that a better understanding of the life cycle of a highly pathogenic virus is often a precondition for developing vaccines and antivirals, it is urgent to develop powerful tools to unravel the molecular basis of the pathogenesis. However, biosafety level −3 or even −4 containment laboratory is considered as a necessary condition for working with a number of bunyaviruses, which has hampered various studies. Reverse genetics systems, including minigenome (MG), infectious virus-like particle (iVLP), and infectious full-length clone (IFLC) systems, are capable of recapitulating some or all steps of the viral replication cycle; among these, the MG and iVLP systems have been very convenient and effective tools, allowing researchers to manipulate the genome segments of pathogenic viruses at lower biocontainment to investigate the viral genome transcription, replication, virus entry, and budding. The IFLC system is generally developed based on the MG or iVLP systems, which have facilitated the generation of recombinant infectious viruses. The MG, iVLP, and IFLC systems have been successfully developed for some important bunyaviruses and have been widely employed as powerful tools to investigate the viral replication cycle, virus–host interactions, virus pathogenesis, and virus evolutionary process. The majority of bunyaviruses is generally enveloped negative-strand RNA viruses with two to six genome segments, of which the viruses with bipartite and tripartite genome segments have mostly been characterized. This review aimed to summarize current knowledge on reverse genetic studies of representative bunyaviruses causing severe diseases in humans and animals, which will contribute to the better understanding of the bunyavirus replication cycle and provide some hints for developing designed antivirals.
Collapse
Affiliation(s)
- Fuli Ren
- Research Center for Translational Medicine, Wuhan Jinyintan Hospital, Wuhan, China.,State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, China.,National Virus Resource Center, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, China
| | - Shu Shen
- State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, China.,National Virus Resource Center, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, China
| | - Qiongya Wang
- Research Center for Translational Medicine, Wuhan Jinyintan Hospital, Wuhan, China
| | - Gang Wei
- Research Center for Translational Medicine, Wuhan Jinyintan Hospital, Wuhan, China
| | - Chaolin Huang
- Research Center for Translational Medicine, Wuhan Jinyintan Hospital, Wuhan, China
| | - Hualin Wang
- State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, China.,National Virus Resource Center, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, China
| | - Yun-Jia Ning
- State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, China.,National Virus Resource Center, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, China
| | - Ding-Yu Zhang
- Research Center for Translational Medicine, Wuhan Jinyintan Hospital, Wuhan, China
| | - Fei Deng
- State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, China.,National Virus Resource Center, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, China
| |
Collapse
|
18
|
Yun SM, Lee TY, Lim HY, Ryou J, Lee JY, Kim YE. Development and Characterization of a Reverse Genetics System for a Human-Derived Severe Fever With Thrombocytopenia Syndrome Virus Isolate From South Korea. Front Microbiol 2021; 12:772802. [PMID: 34867909 PMCID: PMC8636023 DOI: 10.3389/fmicb.2021.772802] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2021] [Accepted: 10/22/2021] [Indexed: 11/17/2022] Open
Abstract
Severe fever with thrombocytopenia syndrome virus (SFTSV) is an emerging, tick-borne Bandavirus that causes lethal disease in humans. As there are no licensed vaccines and therapeutics for SFTSV, there is an urgent need to develop countermeasures against it. In this respect, a reverse genetics (RG) system is a powerful tool to help achieve this goal. Herein, we established a T7 RNA polymerase-driven RG system to rescue infectious clones of a Korean SFTSV human isolate entirely from complementary DNA (cDNA). To establish this system, we cloned cDNAs encoding the three antigenomic segments into transcription vectors, with each segment transcribed under the control of the T7 promoter and the hepatitis delta virus ribozyme (HdvRz) sequences. We also constructed two helper plasmids expressing the nucleoprotein (NP) or viral RNA-dependent RNA polymerase (RdRp) under the control of the T7 promoter and the encephalomyocarditis virus (EMCV) internal ribosome entry site (IRES). After co-transfection into BHK/T7-9 cells with three transcription and two helper plasmids, then passaging in Vero E6 or Huh-7 cells, we confirmed efficient rescue of the recombinant SFTSV. By evaluating the in vitro and in vivo virological properties of the parental and rescued SFTSVs, we show that the rescued virus exhibited biological properties similar to those of the parental virus. This system will be useful for identifying molecular viral determinants of SFTSV infection and pathogenesis and for facilitating the development of vaccine and antiviral approaches.
Collapse
Affiliation(s)
- Seok-Min Yun
- Division of Acute Viral Diseases, Center for Emerging Virus Research, National Institute of Infectious Diseases, National Institute of Health, Korea Disease Control and Prevention Agency, Cheongju-si, South Korea
| | - Tae-Young Lee
- Division of Emerging Virus and Vector Research, Center for Emerging Virus Research, National Institute of Infectious Diseases, National Institute of Health, Korea Disease Control and Prevention Agency, Cheongju-si, South Korea
| | - Hee-Young Lim
- Division of Emerging Virus and Vector Research, Center for Emerging Virus Research, National Institute of Infectious Diseases, National Institute of Health, Korea Disease Control and Prevention Agency, Cheongju-si, South Korea
| | - Jungsang Ryou
- Division of Acute Viral Diseases, Center for Emerging Virus Research, National Institute of Infectious Diseases, National Institute of Health, Korea Disease Control and Prevention Agency, Cheongju-si, South Korea
| | - Joo-Yeon Lee
- Center for Emerging Virus Research, National Institute of Infectious Diseases, National Institute of Health, Korea Disease Control and Prevention Agency, Cheongju-si, South Korea
| | - Young-Eui Kim
- Division of Acute Viral Diseases, Center for Emerging Virus Research, National Institute of Infectious Diseases, National Institute of Health, Korea Disease Control and Prevention Agency, Cheongju-si, South Korea
| |
Collapse
|
19
|
Ren F, Shen S, Ning YJ, Wang Q, Dai S, Shi J, Zhou M, Wang H, Huang C, Zhang DY, Deng F. Non-structural Proteins of Severe Fever With Thrombocytopenia Syndrome Virus Suppress RNA Synthesis in a Transcriptionally Active cDNA-Derived Viral RNA Synthesis System. Front Microbiol 2021; 12:709517. [PMID: 34484148 PMCID: PMC8415556 DOI: 10.3389/fmicb.2021.709517] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2021] [Accepted: 07/23/2021] [Indexed: 11/13/2022] Open
Abstract
Severe fever with thrombocytopenia syndrome (SFTS) is an emerging infectious disease caused by the tick-borne SFTS bunyavirus (SFTSV) resulting in a high fatality rate up to 30%. SFTSV is a negative-strand RNA virus containing three single-stranded RNA genome segments designated as L, M, and S, which respectively, encode the RNA-dependent RNA polymerase (RdRp), glycoproteins Gn and Gc, and nucleoprotein (N) and non-structural proteins (NSs). NSs can form inclusion bodies (IBs) in infected and transfected cells. A previous study has provided a clue that SFTSV NSs may be involved in virus-like or viral RNA synthesis; however, the details remain unclear. Our work described here reveals that SFTSV NSs can downregulate virus-like RNA synthesis in a dose-dependent manner within a cDNA-derived viral RNA synthesis system, i.e., minigenome (−) and minigenome (+) systems based on transfection, superinfection, and luciferase reporter activity determination; meanwhile, NSs also show a weak inhibitory effect on virus replication. By using co-immunoprecipitation (Co-IP) and RT-PCR combined with site-directed mutagenesis, we found that NSs suppress virus-like RNA or virus replication through interacting with N but not with RdRp, and the negative regulatory effect correlates closely with the IB structure it formed but is not associated with its role of antagonizing host innate immune responses. When the cytoplasmic structure of IB formed by SFTSV NSs was deprived, the inhibitory effect of NSs on virus-like RNA synthesis would weaken and even disappear. Similarly, we also evaluated other bandavirus NSs that cannot form IB in neither infected nor transfected cells, and the results showed that the NSs of Heartland bandavirus (HRTV) did not show a significant inhibitory effect on virus-like RNA synthesis within a minigenome system. Our findings provide experimental evidence that SFTSV NSs participate in regulating virus-like or viral RNA synthesis and the negative effect may be due to the NSs–N interaction.
Collapse
Affiliation(s)
- Fuli Ren
- Research Center for Translational Medicine, Wuhan Jinyintan Hospital, Wuhan, China.,State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, China.,National Virus Resource Center, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, China
| | - Shu Shen
- State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, China.,National Virus Resource Center, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, China
| | - Yun-Jia Ning
- State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, China.,National Virus Resource Center, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, China
| | - Qiongya Wang
- Research Center for Translational Medicine, Wuhan Jinyintan Hospital, Wuhan, China
| | - Shiyu Dai
- State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, China.,National Virus Resource Center, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, China
| | - Junming Shi
- State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, China.,National Virus Resource Center, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, China
| | - Min Zhou
- State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, China.,National Virus Resource Center, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, China
| | - Hualin Wang
- State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, China.,National Virus Resource Center, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, China
| | - Chaolin Huang
- Research Center for Translational Medicine, Wuhan Jinyintan Hospital, Wuhan, China.,Department of Infectious Diseases, Wuhan Jinyintan Hospital, Wuhan, China
| | - Ding-Yu Zhang
- Research Center for Translational Medicine, Wuhan Jinyintan Hospital, Wuhan, China
| | - Fei Deng
- State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, China.,National Virus Resource Center, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, China
| |
Collapse
|
20
|
Porcine Reproductive and Respiratory Syndrome Virus: Immune Escape and Application of Reverse Genetics in Attenuated Live Vaccine Development. Vaccines (Basel) 2021; 9:vaccines9050480. [PMID: 34068505 PMCID: PMC8150910 DOI: 10.3390/vaccines9050480] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2021] [Revised: 04/08/2021] [Accepted: 04/11/2021] [Indexed: 01/16/2023] Open
Abstract
Porcine reproductive and respiratory syndrome virus (PRRSV), an RNA virus widely prevalent in pigs, results in significant economic losses worldwide. PRRSV can escape from the host immune response in several processes. Vaccines, including modified live vaccines and inactivated vaccines, are the best available countermeasures against PRRSV infection. However, challenges still exist as the vaccines are not able to induce broad protection. The reason lies in several facts, mainly the variability of PRRSV and the complexity of the interaction between PRRSV and host immune responses, and overcoming these obstacles will require more exploration. Many novel strategies have been proposed to construct more effective vaccines against this evolving and smart virus. In this review, we will describe the mechanisms of how PRRSV induces weak and delayed immune responses, the current vaccines of PRRSV, and the strategies to develop modified live vaccines using reverse genetics systems.
Collapse
|
21
|
A Novel Ebola Virus VP40 Matrix Protein-Based Screening for Identification of Novel Candidate Medical Countermeasures. Viruses 2020; 13:v13010052. [PMID: 33396288 PMCID: PMC7824103 DOI: 10.3390/v13010052] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2020] [Accepted: 12/29/2020] [Indexed: 12/12/2022] Open
Abstract
Filoviruses, such as Ebola virus and Marburg virus, are of significant human health concern. From 2013 to 2016, Ebola virus caused 11,323 fatalities in Western Africa. Since 2018, two Ebola virus disease outbreaks in the Democratic Republic of the Congo resulted in 2354 fatalities. Although there is progress in medical countermeasure (MCM) development (in particular, vaccines and antibody-based therapeutics), the need for efficacious small-molecule therapeutics remains unmet. Here we describe a novel high-throughput screening assay to identify inhibitors of Ebola virus VP40 matrix protein association with viral particle assembly sites on the interior of the host cell plasma membrane. Using this assay, we screened nearly 3000 small molecules and identified several molecules with the desired inhibitory properties. In secondary assays, one identified compound, sangivamycin, inhibited not only Ebola viral infectivity but also that of other viruses. This finding indicates that it is possible for this new VP40-based screening method to identify highly potent MCMs against Ebola virus and its relatives.
Collapse
|
22
|
Vanmechelen B, Stroobants J, Vermeire K, Maes P. Advancing Marburg virus antiviral screening: Optimization of a novel T7 polymerase-independent minigenome system. Antiviral Res 2020; 185:104977. [PMID: 33220335 DOI: 10.1016/j.antiviral.2020.104977] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2020] [Revised: 11/10/2020] [Accepted: 11/16/2020] [Indexed: 12/19/2022]
Abstract
Marburg virus (MARV) is the only known pathogenic filovirus not belonging to the genus Ebolavirus. Minigenomes have proven a useful tool to study MARV, but all existing MARV minigenomes are dependent on the addition of an exogenous T7 RNA polymerase to drive minigenome expression. However, exogenous expression of a T7 polymerase is not always feasible and can act as a confounding factor in compound screening assays. We have developed an alternative minigenome that is controlled by the natively expressed RNA polymerase II. We demonstrate here the characteristics of this new system and its applicability in a wide range of cell types. Our system shows a clear concentration-dependent activity and shows comparable activity to the existing T7 polymerase-based system at higher concentrations, also in difficult-to-transfect cell lines. In addition, we show that our system can be used for compound screening in a 96-well format, thereby providing an attractive alternative to previously developed MARV minigenomes.
Collapse
Affiliation(s)
- Bert Vanmechelen
- Department of Microbiology, Immunology and Transplantation, Rega Institute, Laboratory of Clinical and Epidemiological Virology, KU Leuven, Herestraat 49, box 1040 3000, Leuven, Belgium
| | - Joren Stroobants
- Department of Microbiology, Immunology and Transplantation, Rega Institute, Laboratory of Virology and Chemotherapy, KU Leuven, Herestraat 49, box 1043 3000, Leuven, Belgium
| | - Kurt Vermeire
- Department of Microbiology, Immunology and Transplantation, Rega Institute, Laboratory of Virology and Chemotherapy, KU Leuven, Herestraat 49, box 1043 3000, Leuven, Belgium
| | - Piet Maes
- Department of Microbiology, Immunology and Transplantation, Rega Institute, Laboratory of Clinical and Epidemiological Virology, KU Leuven, Herestraat 49, box 1040 3000, Leuven, Belgium.
| |
Collapse
|
23
|
DeMers HL, He S, Pandit SG, Hannah EE, Zhang Z, Yan F, Green HR, Reyes DF, Hau D, McLarty ME, Altamura L, Taylor-Howell C, Gates-Hollingsworth MA, Qiu X, AuCoin DP. Development of an antigen detection assay for early point-of-care diagnosis of Zaire ebolavirus. PLoS Negl Trop Dis 2020; 14:e0008817. [PMID: 33141837 PMCID: PMC7608863 DOI: 10.1371/journal.pntd.0008817] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2020] [Accepted: 08/30/2020] [Indexed: 12/19/2022] Open
Abstract
The 2013–2016 Ebola virus (EBOV) outbreak in West Africa and the ongoing cases in the Democratic Republic of the Congo have spurred development of a number of medical countermeasures, including rapid Ebola diagnostic tests. The likelihood of transmission increases as the disease progresses due to increasing viral load and potential for contact with others. Early diagnosis of EBOV is essential for halting spread of the disease. Polymerase chain reaction assays are the gold standard for diagnosing Ebola virus disease (EVD), however, they rely on infrastructure and trained personnel that are not available in most resource-limited settings. Rapid diagnostic tests that are capable of detecting virus with reliable sensitivity need to be made available for use in austere environments where laboratory testing is not feasible. The goal of this study was to produce candidate lateral flow immunoassay (LFI) prototypes specific to the EBOV glycoprotein and viral matrix protein, both targets known to be present during EVD. The LFI platform utilizes antibody-based technology to capture and detect targets and is well suited to the needs of EVD diagnosis as it can be performed at the point-of-care, requires no cold chain, provides results in less than twenty minutes and is low cost. Monoclonal antibodies were isolated, characterized and evaluated in the LFI platform. Top performing LFI prototypes were selected, further optimized and confirmed for sensitivity with cultured live EBOV and clinical samples from infected non-human primates. Comparison with a commercially available EBOV rapid diagnostic test that received emergency use approval demonstrates that the glycoprotein-specific LFI developed as a part of this study has improved sensitivity. The outcome of this work presents a diagnostic prototype with the potential to enable earlier diagnosis of EVD in clinical settings and provide healthcare workers with a vital tool for reducing the spread of disease during an outbreak. Ebola virus (EBOV) causes a severe hemorrhagic fever and has an extremely high fatality rate that ranges from 60%-90%. There is no approved treatment or vaccine for this infectious disease and halting spread of the virus relies on identifying and isolating infected patients quickly. The current gold standard, polymerase chain reaction assay, requires patient samples be transported to regional reference laboratories where it often takes days to get results. A handful of Ebola rapid diagnostic tests have been developed, but lack the sensitivity required to detect the virus in earlier stages of the disease. There is great need for more sensitive rapid diagnostic tests that can identify the EBOV infected patients when they first become symptomatic. This study focused on production of high affinity mAbs to two target EBOV proteins for development of a more sensitivity rapid diagnostic test. Efforts have resulted in production of prototype detecting the EBOV glycoprotein that shows a notable improvement in sensitivity and offers the potential for earlier diagnosis of infection.
Collapse
Affiliation(s)
- Haley L. DeMers
- Department of Microbiology and Immunology, University of Nevada, Reno School of Medicine Reno, Nevada, United States of America
| | - Shihua He
- Special Pathogens Program, National Microbiology Laboratory, Public Health Agency of Canada, Winnipeg, Manitoba, Canada
| | - Sujata G. Pandit
- Department of Microbiology and Immunology, University of Nevada, Reno School of Medicine Reno, Nevada, United States of America
| | - Emily E. Hannah
- Department of Microbiology and Immunology, University of Nevada, Reno School of Medicine Reno, Nevada, United States of America
| | - Zirui Zhang
- Special Pathogens Program, National Microbiology Laboratory, Public Health Agency of Canada, Winnipeg, Manitoba, Canada
- Department of Medical Microbiology, University of Manitoba, Winnipeg, Manitoba, Canada
| | - Feihu Yan
- Department of Medical Microbiology, University of Manitoba, Winnipeg, Manitoba, Canada
| | - Heather R. Green
- Department of Microbiology and Immunology, University of Nevada, Reno School of Medicine Reno, Nevada, United States of America
| | - Denise F. Reyes
- Department of Microbiology and Immunology, University of Nevada, Reno School of Medicine Reno, Nevada, United States of America
| | - Derrick Hau
- Department of Microbiology and Immunology, University of Nevada, Reno School of Medicine Reno, Nevada, United States of America
| | - Megan E. McLarty
- Department of Microbiology and Immunology, University of Nevada, Reno School of Medicine Reno, Nevada, United States of America
| | - Louis Altamura
- Diagnostic Systems Division, United States Army Medical Research Institute of Infectious Diseases, Fort Detrick, Maryland, United States of America
| | - Cheryl Taylor-Howell
- Diagnostic Systems Division, United States Army Medical Research Institute of Infectious Diseases, Fort Detrick, Maryland, United States of America
| | | | - Xiangguo Qiu
- Special Pathogens Program, National Microbiology Laboratory, Public Health Agency of Canada, Winnipeg, Manitoba, Canada
- * E-mail: (XQ); (DPA)
| | - David P. AuCoin
- Department of Microbiology and Immunology, University of Nevada, Reno School of Medicine Reno, Nevada, United States of America
- * E-mail: (XQ); (DPA)
| |
Collapse
|
24
|
The Integrity of the YxxL Motif of Ebola Virus VP24 Is Important for the Transport of Nucleocapsid-Like Structures and for the Regulation of Viral RNA Synthesis. J Virol 2020; 94:JVI.02170-19. [PMID: 32102881 DOI: 10.1128/jvi.02170-19] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2020] [Accepted: 02/15/2020] [Indexed: 12/15/2022] Open
Abstract
While it is well appreciated that late domains in the viral matrix proteins are crucial to mediate efficient virus budding, little is known about roles of late domains in the viral nucleocapsid proteins. Here, we characterized the functional relevance of a YxxL motif with potential late-domain function in the Ebola virus nucleocapsid protein VP24. Mutations in the YxxL motif had two opposing effects on the functions of VP24. On the one hand, the mutation affected the regulatory function of VP24 in viral RNA transcription and replication, which correlated with an increased incorporation of minigenomes into released transcription- and replication-competent virus-like particles (trVLPs). Consequently, cells infected with those trVLPs showed higher levels of viral transcription. On the other hand, mutations of the YxxL motif greatly impaired the intracellular transport of nucleocapsid-like structures (NCLSs) composed of the viral proteins NP, VP35, and VP24 and the length of released trVLPs. Attempts to rescue recombinant Ebola virus expressing YxxL-deficient VP24 failed, underlining the importance of this motif for the viral life cycle.IMPORTANCE Ebola virus (EBOV) causes a severe fever with high case fatality rates and, so far, no available specific therapy. Understanding the interplay between viral and host proteins is important to identify new therapeutic approaches. VP24 is one of the essential nucleocapsid components and is necessary to regulate viral RNA synthesis and condense viral nucleocapsids before their transport to the plasma membrane. Our functional analyses of the YxxL motif in VP24 suggested that it serves as an interface between nucleocapsid-like structures (NCLSs) and cellular proteins, promoting intracellular transport of NCLSs in an Alix-independent manner. Moreover, the YxxL motif is necessary for the inhibitory function of VP24 in viral RNA synthesis. A failure to rescue EBOV encoding VP24 with a mutated YxxL motif indicated that the integrity of the YxxL motif is essential for EBOV growth. Thus, this motif might represent a potential target for antiviral interference.
Collapse
|
25
|
Abstract
The largest Ebola virus (EBOV) epidemic in West Africa ever caused more than 28,000 cases and 11,000 deaths, and the current EBOV epidemic in the Democratic Republic of the Congo continues, with more than 3,000 cases to date. Therefore, it is essential to develop antivirals against EBOV. Recently, an inhibitor of the cellular phosphatase PP2A-mediated dephosphorylation of the EBOV transcription factor VP30 has been shown to suppress the spread of Ebola virus. Here, we identified the protein kinase SRPK1 as a VP30-specific kinase that phosphorylates serine 29, the same residue that is dephosphorylated by PP2A. SRPK1-mediated phosphorylation of serine 29 enabled primary viral transcription. Mutation of the SRPK1 recognition motif in VP30 resulted in significant growth inhibition of EBOV. Similarly, elevation of the phosphorylation status of serine 29 by overexpression of SRPK1 inhibited EBOV growth, highlighting the importance of reversible phosphorylation of VP30 as a potential therapeutic target. Ebola virus (EBOV) causes a severe and often fatal disease for which no approved vaccines or antivirals are currently available. EBOV VP30 has been described as a viral phosphoprotein, and nonphosphorylated VP30 is essential and sufficient to support secondary transcription in an EBOV-specific minigenome system; however, phosphorylatable serine residues near the N terminus of VP30 are required to support primary viral transcription as well as the reinitiation of VP30-mediated transcription at internal EBOV genes. While the dephosphorylation of VP30 by the cellular phosphatase PP2A was found to be mediated by nucleoprotein, the VP30-specific kinases and the role of phosphorylation remain unknown. Here, we report that serine-arginine protein kinase 1 (SRPK1) and SRPK2 phosphorylate serine 29 of VP30, which is located in an N-terminal R26xxS29 motif. Interaction with VP30 via the R26xxS29 motif recruits SRPK1 into EBOV-induced inclusion bodies, the sites of viral RNA synthesis, and an inhibitor of SRPK1/SRPK2 downregulates primary viral transcription. When the SRPK1 recognition motif of VP30 was mutated in a recombinant EBOV, virus replication was severely impaired. It is presumed that the interplay between SRPK1 and PP2A in the EBOV inclusions provides a comprehensive regulatory circuit to ensure the activity of VP30 in EBOV transcription. Thus, the identification of SRPK1 is an important mosaic stone that completes our picture of the players involved in Ebola virus transcription regulation.
Collapse
|
26
|
Duplantier AJ, Shurtleff AC, Miller C, Chiang CY, Panchal RG, Sunay M. Combating biothreat pathogens: ongoing efforts for countermeasure development and unique challenges. DRUG DISCOVERY TARGETING DRUG-RESISTANT BACTERIA 2020. [PMCID: PMC7258707 DOI: 10.1016/b978-0-12-818480-6.00007-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Research to discover and develop antibacterial and antiviral drugs with potent activity against pathogens of biothreat concern presents unique methodological and process-driven challenges. Herein, we review laboratory approaches for finding new antibodies, antibiotics, and antiviral molecules for pathogens of biothreat concern. Using high-throughput screening techniques, molecules that directly inhibit a pathogen’s entry, replication, or growth can be identified. Alternatively, molecules that target host proteins can be interesting targets for development when countering biothreat pathogens, due to the modulation of the host immune response or targeting proteins that interfere with the pathways required by the pathogen for replication. Monoclonal and cocktail antibody therapies approved by the Food and Drug Administration for countering anthrax and under development for treatment of Ebola virus infection are discussed. A comprehensive tabular review of current in vitro, in vivo, pharmacokinetic and efficacy datasets has been presented for biothreat pathogens of greatest concern. Finally, clinical trials and animal rule or traditional drug approval pathways are also reviewed. Opinions; interpretations; conclusions; and recommendations are those of the authors and are not necessarily endorsed by the US Army.
Collapse
|
27
|
Takamatsu Y, Dolnik O, Noda T, Becker S. A live-cell imaging system for visualizing the transport of Marburg virus nucleocapsid-like structures. Virol J 2019; 16:159. [PMID: 31856881 PMCID: PMC6923871 DOI: 10.1186/s12985-019-1267-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2019] [Accepted: 12/05/2019] [Indexed: 01/22/2023] Open
Abstract
Background Live-cell imaging is a powerful tool for visualization of the spatio-temporal dynamics of moving signals in living cells. Although this technique can be utilized to visualize nucleocapsid transport in Marburg virus (MARV)- or Ebola virus-infected cells, the experiments require biosafety level-4 (BSL-4) laboratories, which are restricted to trained and authorized individuals. Methods To overcome this limitation, we developed a live-cell imaging system to visualize MARV nucleocapsid-like structures using fluorescence-conjugated viral proteins, which can be conducted outside BSL-4 laboratories. Results Our experiments revealed that nucleocapsid-like structures have similar transport characteristics to those of nucleocapsids observed in MARV-infected cells, both of which are mediated by actin polymerization. Conclusions We developed a non-infectious live cell imaging system to visualize intracellular transport of MARV nucleocapsid-like structures. This system provides a safe platform to evaluate antiviral drugs that inhibit MARV nucleocapsid transport.
Collapse
Affiliation(s)
- Yuki Takamatsu
- Institute of Virology, Philipps-University Marburg, Hans-Meerwein-Straße, 35043, Marburg, Germany.,Laboratory of Ultrastructural Virology, Institute for Frontier Life and Medical Sciences, Kyoto University, Shogoin-Kawahara-cho 53, Sakyo-ku, Kyoto, 606-8507, Japan
| | - Olga Dolnik
- Institute of Virology, Philipps-University Marburg, Hans-Meerwein-Straße, 35043, Marburg, Germany
| | - Takeshi Noda
- Laboratory of Ultrastructural Virology, Institute for Frontier Life and Medical Sciences, Kyoto University, Shogoin-Kawahara-cho 53, Sakyo-ku, Kyoto, 606-8507, Japan. .,Laboratory of Ultrastructural Virology, Graduate School of Biostudies, Kyoto University, Shogoin-Kawahara-cho 53, Sakyo-ku, Kyoto, 606-8507, Japan.
| | - Stephan Becker
- Institute of Virology, Philipps-University Marburg, Hans-Meerwein-Straße, 35043, Marburg, Germany. .,German Center of Infection Research (DZIF), partner site Giessen-Marburg-Langen, Marburg, Germany.
| |
Collapse
|
28
|
Shu T, Gan T, Bai P, Wang X, Qian Q, Zhou H, Cheng Q, Qiu Y, Yin L, Zhong J, Zhou X. Ebola virus VP35 has novel NTPase and helicase-like activities. Nucleic Acids Res 2019; 47:5837-5851. [PMID: 31066445 PMCID: PMC6582406 DOI: 10.1093/nar/gkz340] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2018] [Revised: 04/21/2019] [Accepted: 04/25/2019] [Indexed: 12/13/2022] Open
Abstract
Ebola virus (EBOV) is a non-segmented, negative-sense RNA virus (NNSV) in the family Filoviridae, and is recognized as one of the most lethal pathogens in the planet. For RNA viruses, cellular or virus-encoded RNA helicases play pivotal roles in viral life cycles by remodelling viral RNA structures and/or unwinding viral dsRNA produced during replication. However, no helicase or helicase-like activity has ever been found to associate with any NNSV-encoded proteins, and it is unknown whether the replication of NNSVs requires the participation of any viral or cellular helicase. Here, we show that despite of containing no conserved NTPase/helicase motifs, EBOV VP35 possesses the NTPase and helicase-like activities that can hydrolyse all types of NTPs and unwind RNA helices in an NTP-dependent manner, respectively. Moreover, guanidine hydrochloride, an FDA-approved compound and inhibitor of certain viral helicases, inhibited the NTPase and helicase-like activities of VP35 as well as the replication/transcription of an EBOV minigenome replicon in cells, highlighting the importance of VP35 helicase-like activity during EBOV life cycle. Together, our findings provide the first demonstration of the NTPase/helicase-like activity encoded by EBOV, and would foster our understanding of EBOV and NNSVs.
Collapse
Affiliation(s)
- Ting Shu
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan, Hubei 430072, China
| | - Tianyu Gan
- Unit of Viral Hepatitis, CAS Key Laboratory of Molecular Virology and Immunology, Institut Pasteur of Shanghai, CAS, Shanghai 200031, China.,University of Chinese Academy of Sciences, Beijing 100049, China
| | - Peng Bai
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan, Hubei 430072, China
| | - Xiaotong Wang
- University of Chinese Academy of Sciences, Beijing 100049, China.,State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences (CAS), Wuhan, Hubei 430071, China.,Wuhan National Biosafety Laboratory, Mega-Science Center for Bio-Safety Research, CAS, Wuhan, Hubei 430071, China
| | - Qi Qian
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan, Hubei 430072, China.,State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences (CAS), Wuhan, Hubei 430071, China.,Wuhan National Biosafety Laboratory, Mega-Science Center for Bio-Safety Research, CAS, Wuhan, Hubei 430071, China
| | - Hui Zhou
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan, Hubei 430072, China.,State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences (CAS), Wuhan, Hubei 430071, China.,Wuhan National Biosafety Laboratory, Mega-Science Center for Bio-Safety Research, CAS, Wuhan, Hubei 430071, China
| | - Qi Cheng
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan, Hubei 430072, China
| | - Yang Qiu
- University of Chinese Academy of Sciences, Beijing 100049, China.,State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences (CAS), Wuhan, Hubei 430071, China.,Wuhan National Biosafety Laboratory, Mega-Science Center for Bio-Safety Research, CAS, Wuhan, Hubei 430071, China
| | - Lei Yin
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan, Hubei 430072, China
| | - Jin Zhong
- Unit of Viral Hepatitis, CAS Key Laboratory of Molecular Virology and Immunology, Institut Pasteur of Shanghai, CAS, Shanghai 200031, China.,Wuhan National Biosafety Laboratory, Mega-Science Center for Bio-Safety Research, CAS, Wuhan, Hubei 430071, China
| | - Xi Zhou
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan, Hubei 430072, China.,University of Chinese Academy of Sciences, Beijing 100049, China.,State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences (CAS), Wuhan, Hubei 430071, China.,Wuhan National Biosafety Laboratory, Mega-Science Center for Bio-Safety Research, CAS, Wuhan, Hubei 430071, China
| |
Collapse
|
29
|
Du X, Zuo X, Meng F, Wu F, Zhao X, Li C, Cheng G, Qin FXF. Combinatorial screening of a panel of FDA-approved drugs identifies several candidates with anti-Ebola activities. Biochem Biophys Res Commun 2019; 522:862-868. [PMID: 31806372 DOI: 10.1016/j.bbrc.2019.11.065] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2019] [Accepted: 11/10/2019] [Indexed: 01/16/2023]
Abstract
Ebola virus (EBOV), pathogen of Ebola hemorrhagic fever (EHF), is an enveloped filamental RNA virus. Recently, the EHF crisis occurred in the Democratic Republic of the Congo again highlights the urgency for its clinical treatments. However, no Food and Drug Administration (FDA)-approved therapeutics are currently available. Drug repurposing screening is a time- and cost-effective approach for identifying anti-EBOV therapeutics. Here, by combinatorial screening using pseudovirion and minigenome replicon systems we have identified several FDA-approved drugs with significant anti-EBOV activities. These potential candidates include azithromycin, clomiphene, chloroquine, digitoxin, epigallocatechin-gallate, fluvastatin, tetrandrine and tamoxifen. Mechanistic studies revealed that fluvastatin inhibited EBOV pseudovirion entry by blocking the pathway of mevalonate biosynthesis, while the inhibitory effect of azithromycin on EBOV maybe due to its intrinsic cationic amphiphilic structure altering the homeostasis of later endosomal vesicle similar as tamoxifen. Moreover, based on structure and pathway analyses, the anti-EBOV activity has been extended to other family members of statins, such as simvastatin, and multiple other cardiac glycoside drugs, some of which exhibited even stronger activities. More importantly, in searching for drug interaction, we found various synergy between several anti-EBOV drug combinations, showing substantial and powerful synergistic against EBOV infection. In conclusion, our work illustrates a successful and productive approach to identify new mechanisms and targets for treating EBOV infection by combinatorial screening of FDA-approved drugs.
Collapse
Affiliation(s)
- Xiaohong Du
- Center of Systems Medicine, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, 100005, China; Suzhou Institute of Systems Medicine, Suzhou, Jiangsu, 215123, China
| | - Xiangyang Zuo
- Center of Systems Medicine, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, 100005, China; Suzhou Institute of Systems Medicine, Suzhou, Jiangsu, 215123, China
| | - Fang Meng
- Center of Systems Medicine, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, 100005, China; Suzhou Institute of Systems Medicine, Suzhou, Jiangsu, 215123, China
| | - Fei Wu
- Center of Systems Medicine, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, 100005, China; Suzhou Institute of Systems Medicine, Suzhou, Jiangsu, 215123, China
| | - Xin Zhao
- Center of Systems Medicine, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, 100005, China; Suzhou Institute of Systems Medicine, Suzhou, Jiangsu, 215123, China
| | - Chunfeng Li
- Center of Systems Medicine, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, 100005, China; Suzhou Institute of Systems Medicine, Suzhou, Jiangsu, 215123, China
| | - Genhong Cheng
- Center of Systems Medicine, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, 100005, China; Suzhou Institute of Systems Medicine, Suzhou, Jiangsu, 215123, China; Department of Microbiology, Immunology and Molecular Genetics, University of California, Los Angeles, CA, 90095, USA
| | - F Xiao-Feng Qin
- Center of Systems Medicine, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, 100005, China; Suzhou Institute of Systems Medicine, Suzhou, Jiangsu, 215123, China.
| |
Collapse
|
30
|
Hume AJ, Mühlberger E. Distinct Genome Replication and Transcription Strategies within the Growing Filovirus Family. J Mol Biol 2019; 431:4290-4320. [PMID: 31260690 PMCID: PMC6879820 DOI: 10.1016/j.jmb.2019.06.029] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2019] [Revised: 05/31/2019] [Accepted: 06/24/2019] [Indexed: 11/18/2022]
Abstract
Research on filoviruses has historically focused on the highly pathogenic ebola- and marburgviruses. Indeed, until recently, these were the only two genera in the filovirus family. Recent advances in sequencing technologies have facilitated the discovery of not only a new ebolavirus, but also three new filovirus genera and a sixth proposed genus. While two of these new genera are similar to the ebola- and marburgviruses, the other two, discovered in saltwater fishes, are considerably more diverse. Nonetheless, these viruses retain a number of key features of the other filoviruses. Here, we review the key characteristics of filovirus replication and transcription, highlighting similarities and differences between the viruses. In particular, we focus on key regulatory elements in the genomes, replication and transcription strategies, and the conservation of protein domains and functions among the viruses. In addition, using computational analyses, we were able to identify potential homology and functions for some of the genes of the novel filoviruses with previously unknown functions. Although none of the newly discovered filoviruses have yet been isolated, initial studies of some of these viruses using minigenome systems have yielded insights into their mechanisms of replication and transcription. In general, the Cuevavirus and proposed Dianlovirus genera appear to follow the transcription and replication strategies employed by the ebola- and marburgviruses, respectively. While our knowledge of the fish filoviruses is currently limited to sequence analysis, the lack of certain conserved motifs and even entire genes necessitates that they have evolved distinct mechanisms of replication and transcription.
Collapse
Affiliation(s)
- Adam J Hume
- Department of Microbiology, Boston University School of Medicine, Boston, MA 02118, USA; National Emerging Infectious Diseases Laboratories, Boston University, Boston, MA 02118, USA
| | - Elke Mühlberger
- Department of Microbiology, Boston University School of Medicine, Boston, MA 02118, USA; National Emerging Infectious Diseases Laboratories, Boston University, Boston, MA 02118, USA.
| |
Collapse
|
31
|
Therapeutic strategies to target the Ebola virus life cycle. Nat Rev Microbiol 2019; 17:593-606. [DOI: 10.1038/s41579-019-0233-2] [Citation(s) in RCA: 81] [Impact Index Per Article: 16.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/18/2019] [Indexed: 02/07/2023]
|
32
|
Abstract
This chapter reviews our current knowledge about the spatiotemporal assembly of filoviral particles. We will follow particles from nucleocapsid entry into the cytoplasm until the nucleocapsids are enveloped at the plasma membrane. We will also highlight the currently open scientific questions surrounding filovirus assembly.
Collapse
|
33
|
Kämper L, Zierke L, Schmidt ML, Müller A, Wendt L, Brandt J, Hartmann E, Braun S, Holzerland J, Groseth A, Hoenen T. Assessment of the function and intergenus-compatibility of Ebola and Lloviu virus proteins. J Gen Virol 2019; 100:760-772. [DOI: 10.1099/jgv.0.001261] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Affiliation(s)
- Lennart Kämper
- 1 Institute for Molecular Virology and Cell Biology, Friedrich-Loeffler-Institut, Greifswald – Insel Riems, Germany
| | - Lukas Zierke
- 1 Institute for Molecular Virology and Cell Biology, Friedrich-Loeffler-Institut, Greifswald – Insel Riems, Germany
| | - Marie Luisa Schmidt
- 1 Institute for Molecular Virology and Cell Biology, Friedrich-Loeffler-Institut, Greifswald – Insel Riems, Germany
| | - Andreas Müller
- 1 Institute for Molecular Virology and Cell Biology, Friedrich-Loeffler-Institut, Greifswald – Insel Riems, Germany
| | - Lisa Wendt
- 1 Institute for Molecular Virology and Cell Biology, Friedrich-Loeffler-Institut, Greifswald – Insel Riems, Germany
| | - Janine Brandt
- 1 Institute for Molecular Virology and Cell Biology, Friedrich-Loeffler-Institut, Greifswald – Insel Riems, Germany
| | - Eric Hartmann
- 1 Institute for Molecular Virology and Cell Biology, Friedrich-Loeffler-Institut, Greifswald – Insel Riems, Germany
| | - Stefanie Braun
- 1 Institute for Molecular Virology and Cell Biology, Friedrich-Loeffler-Institut, Greifswald – Insel Riems, Germany
| | - Julia Holzerland
- 2 Junior Research Group Arenavirus Biology, Friedrich-Loeffler-Institut, Greifswald – Insel Riems, Germany
| | - Allison Groseth
- 2 Junior Research Group Arenavirus Biology, Friedrich-Loeffler-Institut, Greifswald – Insel Riems, Germany
| | - Thomas Hoenen
- 1 Institute for Molecular Virology and Cell Biology, Friedrich-Loeffler-Institut, Greifswald – Insel Riems, Germany
| |
Collapse
|
34
|
Bhat SM, Mudgal PP, N S, Arunkumar G. Spectrum of candidate molecules against Chikungunya virus - an insight into the antiviral screening platforms. Expert Rev Anti Infect Ther 2019; 17:243-264. [PMID: 30889372 DOI: 10.1080/14787210.2019.1595591] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
INTRODUCTION Chikungunya disease has undergone a phenomenal transition in its status from being recognized as a sporadic infection to acquiring a global prominence over the last couple of decades. The causative agent behind the explosive epidemics worldwide is the re-emerging pathogen, Chikungunya virus (CHIKV). Areas covered: The current review discusses all the possible avenues of antiviral research towards combating CHIKV infection. Aspects of antiviral drug discovery such as antiviral targets, candidate molecules screened, and the various criteria to be a potential inhibitor are all discussed at length. Existing antiviral drug screening tools for CHIKV and their applications are thoroughly described. Clinical trial status of agents with therapeutic potential has been updated with special mention of candidate molecules under patent approval. Databases such as PubMed, Google Scholar, ScienceDirect, Google Patent, and Clinical Trial Registry platforms were referred. Expert opinion: The massive outbreaks of Chikungunya viral disease in the recent past and the serious health concerns imposed thereby, have driven the search for effective therapeutics. The greatest challenge being the non-availability of robust, reproducible, cost-effective and biologically accurate assay models. Nevertheless, there is a need to identify good models mimicking the appropriate microenvironment of an infectious setting.
Collapse
Affiliation(s)
- Shree Madhu Bhat
- a Manipal Centre for Virus Research , Manipal Academy of Higher Education (Deemed to be University) , Manipal , Karnataka , India
| | - Piya Paul Mudgal
- a Manipal Centre for Virus Research , Manipal Academy of Higher Education (Deemed to be University) , Manipal , Karnataka , India
| | - Sudheesh N
- a Manipal Centre for Virus Research , Manipal Academy of Higher Education (Deemed to be University) , Manipal , Karnataka , India
| | - Govindakarnavar Arunkumar
- a Manipal Centre for Virus Research , Manipal Academy of Higher Education (Deemed to be University) , Manipal , Karnataka , India
| |
Collapse
|
35
|
Salata C, Calistri A, Alvisi G, Celestino M, Parolin C, Palù G. Ebola Virus Entry: From Molecular Characterization to Drug Discovery. Viruses 2019; 11:v11030274. [PMID: 30893774 PMCID: PMC6466262 DOI: 10.3390/v11030274] [Citation(s) in RCA: 52] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2019] [Revised: 03/15/2019] [Accepted: 03/16/2019] [Indexed: 02/06/2023] Open
Abstract
Ebola Virus Disease (EVD) is one of the most lethal transmissible infections, characterized by a high fatality rate, and caused by a member of the Filoviridae family. The recent large outbreak of EVD in Western Africa (2013–2016) highlighted the worldwide threat represented by the disease and its impact on global public health and the economy. The development of highly needed anti-Ebola virus antivirals has been so far hampered by the shortage of tools to study their life cycle in vitro, allowing to screen for potential active compounds outside a biosafety level-4 (BSL-4) containment. Importantly, the development of surrogate models to study Ebola virus entry in a BSL-2 setting, such as viral pseudotypes and Ebola virus-like particles, tremendously boosted both our knowledge of the viral life cycle and the identification of promising antiviral compounds interfering with viral entry. In this context, the combination of such surrogate systems with large-scale small molecule compounds and haploid genetic screenings, as well as rational drug design and drug repurposing approaches will prove priceless in our quest for the development of a treatment for EVD.
Collapse
Affiliation(s)
- Cristiano Salata
- Department of Molecular Medicine, University of Padova, IT-35121 Padova, Italy.
| | - Arianna Calistri
- Department of Molecular Medicine, University of Padova, IT-35121 Padova, Italy.
| | - Gualtiero Alvisi
- Department of Molecular Medicine, University of Padova, IT-35121 Padova, Italy.
| | - Michele Celestino
- Department of Molecular Medicine, University of Padova, IT-35121 Padova, Italy.
| | - Cristina Parolin
- Department of Molecular Medicine, University of Padova, IT-35121 Padova, Italy.
| | - Giorgio Palù
- Department of Molecular Medicine, University of Padova, IT-35121 Padova, Italy.
| |
Collapse
|
36
|
Gutierrez B, Escalera-Zamudio M, Pybus OG. Parallel molecular evolution and adaptation in viruses. Curr Opin Virol 2019; 34:90-96. [PMID: 30703578 PMCID: PMC7102768 DOI: 10.1016/j.coviro.2018.12.006] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2018] [Accepted: 12/11/2018] [Indexed: 01/05/2023]
Abstract
Parallel molecular evolution is the independent evolution of the same genotype or phenotype from distinct ancestors. The simple genomes and rapid evolution of many viruses mean they are useful model systems for studying parallel evolution by natural selection. Parallel adaptation occurs in the context of several viral behaviours, including cross-species transmission, drug resistance, and host immune escape, and its existence suggests that at least some aspects of virus evolution and emergence are repeatable and predictable. We introduce examples of virus parallel evolution and summarise key concepts. We outline the difficulties in detecting parallel adaptation using virus genomes, with a particular focus on phylogenetic and structural approaches, and we discuss future approaches that may improve our understanding of the phenomenon.
Collapse
Affiliation(s)
| | | | - Oliver G Pybus
- Department of Zoology, University of Oxford, Oxford, United Kingdom.
| |
Collapse
|
37
|
Staufen1 Interacts with Multiple Components of the Ebola Virus Ribonucleoprotein and Enhances Viral RNA Synthesis. mBio 2018; 9:mBio.01771-18. [PMID: 30301857 PMCID: PMC6178623 DOI: 10.1128/mbio.01771-18] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
Abstract
Ebola virus (EBOV) is a negative-strand RNA virus with significant public health importance. Currently, no therapeutics are available for Ebola, which imposes an urgent need for a better understanding of EBOV biology. Here we dissected the virus-host interplay between EBOV and host RNA-binding proteins. We identified novel EBOV host factors, including Staufen1, which interacts with multiple viral factors and is required for efficient viral RNA synthesis. Ebola virus (EBOV) genome and mRNAs contain long, structured regions that could hijack host RNA-binding proteins to facilitate infection. We performed RNA affinity chromatography coupled with mass spectrometry to identify host proteins that bind to EBOV RNAs and identified four high-confidence proviral host factors, including Staufen1 (STAU1), which specifically binds both 3′ and 5′ extracistronic regions of the EBOV genome. We confirmed that EBOV infection rate and production of infectious particles were significantly reduced in STAU1-depleted cells. STAU1 was recruited to sites of EBOV RNA synthesis upon infection and enhanced viral RNA synthesis. Furthermore, STAU1 interacts with EBOV nucleoprotein (NP), virion protein 30 (VP30), and VP35; the latter two bridge the viral polymerase to the NP-coated genome, forming the viral ribonucleoprotein (RNP) complex. Our data indicate that STAU1 plays a critical role in EBOV replication by coordinating interactions between the viral genome and RNA synthesis machinery.
Collapse
|
38
|
Dunham EC, Leske A, Shifflett K, Watt A, Feldmann H, Hoenen T, Groseth A. Lifecycle modelling systems support inosine monophosphate dehydrogenase (IMPDH) as a pro-viral factor and antiviral target for New World arenaviruses. Antiviral Res 2018; 157:140-150. [PMID: 30031760 PMCID: PMC11099991 DOI: 10.1016/j.antiviral.2018.07.009] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2018] [Revised: 06/14/2018] [Accepted: 07/16/2018] [Indexed: 12/24/2022]
Abstract
Infection with Junín virus (JUNV) is currently being effectively managed in the endemic region using a combination of targeted vaccination and plasma therapy. However, the long-term sustainability of plasma therapy is unclear and similar resources are not available for other New World arenaviruses. As a result, there has been renewed interest regarding the potential of drug-based therapies. To facilitate work on this issue, we present the establishment and subsequent optimization of a JUNV minigenome system to a degree suitable for high-throughput miniaturization, thereby providing a screening platform focused solely on factors affecting RNA synthesis. Using this tool, we conducted a limited drug library screen and identified AVN-944, a non-competitive inosine monophosphate dehydrogenase (IMPDH) inhibitor, as an inhibitor of arenavirus RNA synthesis. We further developed a transcription and replication competent virus-like particle (trVLP) system based on these minigenomes and used it to screen siRNAs against IMPDH, verifying its role in supporting arenavirus RNA synthesis. The antiviral effect of AVN-944, as well as siRNA inhibition, on JUNV RNA synthesis supports that, despite playing only a minor role in the activity of ribavirin, exclusive IMPDH inhibitors may indeed have significant therapeutic potential for use against New World arenaviruses. Finally, we confirmed that AVN-944 is also active against arenavirus infection in cell culture, supporting the suitability of arenavirus lifecycle modelling systems as tools for the screening and identification, as well as the mechanistic characterization, of novel antiviral compounds.
Collapse
Affiliation(s)
- Eric C Dunham
- Laboratory of Virology, Division of Intramural Research, National Institute of Allergy and Infectious Diseases (NIAID), National Institutes of Health (NIH), Hamilton, MT, USA.
| | - Anne Leske
- Junior Research Group Arenavirus Biology, Friedrich-Loeffler-Institut, Greifswald, Insel Riems, Germany.
| | - Kyle Shifflett
- Laboratory of Virology, Division of Intramural Research, National Institute of Allergy and Infectious Diseases (NIAID), National Institutes of Health (NIH), Hamilton, MT, USA.
| | - Ari Watt
- Laboratory of Virology, Division of Intramural Research, National Institute of Allergy and Infectious Diseases (NIAID), National Institutes of Health (NIH), Hamilton, MT, USA.
| | - Heinz Feldmann
- Laboratory of Virology, Division of Intramural Research, National Institute of Allergy and Infectious Diseases (NIAID), National Institutes of Health (NIH), Hamilton, MT, USA.
| | - Thomas Hoenen
- Laboratory of Virology, Division of Intramural Research, National Institute of Allergy and Infectious Diseases (NIAID), National Institutes of Health (NIH), Hamilton, MT, USA; Institute of Molecular Virology and Cell Biology, Friedrich-Loeffler-Institut, Greifswald, Insel Riems, Germany.
| | - Allison Groseth
- Laboratory of Virology, Division of Intramural Research, National Institute of Allergy and Infectious Diseases (NIAID), National Institutes of Health (NIH), Hamilton, MT, USA; Junior Research Group Arenavirus Biology, Friedrich-Loeffler-Institut, Greifswald, Insel Riems, Germany.
| |
Collapse
|
39
|
Martin S, Chiramel AI, Schmidt ML, Chen YC, Whitt N, Watt A, Dunham EC, Shifflett K, Traeger S, Leske A, Buehler E, Martellaro C, Brandt J, Wendt L, Müller A, Peitsch S, Best SM, Stech J, Finke S, Römer-Oberdörfer A, Groseth A, Feldmann H, Hoenen T. A genome-wide siRNA screen identifies a druggable host pathway essential for the Ebola virus life cycle. Genome Med 2018; 10:58. [PMID: 30081931 PMCID: PMC6090742 DOI: 10.1186/s13073-018-0570-1] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2018] [Accepted: 07/13/2018] [Indexed: 01/01/2023] Open
Abstract
Background The 2014–2016 Ebola virus (EBOV) outbreak in West Africa highlighted the need for improved therapeutic options against this virus. Approaches targeting host factors/pathways essential for the virus are advantageous because they can potentially target a wide range of viruses, including newly emerging ones and because the development of resistance is less likely than when targeting the virus directly. However, systematic approaches for screening host factors important for EBOV have been hampered by the necessity to work with this virus at biosafety level 4 (BSL4). Methods In order to identify host factors involved in the EBOV life cycle, we performed a genome-wide siRNA screen comprising 64,755 individual siRNAs against 21,566 human genes to assess their activity in EBOV genome replication and transcription. As a screening platform, we used reverse genetics-based life cycle modelling systems that recapitulate these processes without the need for a BSL4 laboratory. Results Among others, we identified the de novo pyrimidine synthesis pathway as an essential host pathway for EBOV genome replication and transcription, and confirmed this using infectious EBOV under BSL4 conditions. An FDA-approved drug targeting this pathway showed antiviral activity against infectious EBOV, as well as other non-segmented negative-sense RNA viruses. Conclusions This study provides a minable data set for every human gene regarding its role in EBOV genome replication and transcription, shows that an FDA-approved drug targeting one of the identified pathways is highly efficacious in vitro, and demonstrates the power of life cycle modelling systems for conducting genome-wide host factor screens for BSL4 viruses. Electronic supplementary material The online version of this article (10.1186/s13073-018-0570-1) contains supplementary material, which is available to authorized users.
Collapse
Affiliation(s)
- Scott Martin
- Division of Preclinical Innovation, National Center for Advancing Translational Sciences, National Institutes of Health, 31 Center Drive, Bethesda, MD, 20892, USA.,Present address: Department of Discovery Oncology, Genentech, 1 DNA Way, South San Francisco, CA, 94080, USA
| | - Abhilash I Chiramel
- Laboratory of Virology, Division of Intramural Research, National Institute for Allergy and Infectious Diseases, National Institutes of Health, 903 S 4th St., Hamilton, MT, 59840, USA
| | - Marie Luisa Schmidt
- Institute of Molecular Virology and Cell Biology, Friedrich-Loeffler-Institut, Südufer 10, 17493, Greifswald, Insel Riems, Germany
| | - Yu-Chi Chen
- Division of Preclinical Innovation, National Center for Advancing Translational Sciences, National Institutes of Health, 31 Center Drive, Bethesda, MD, 20892, USA
| | - Nadia Whitt
- Division of Preclinical Innovation, National Center for Advancing Translational Sciences, National Institutes of Health, 31 Center Drive, Bethesda, MD, 20892, USA
| | - Ari Watt
- Laboratory of Virology, Division of Intramural Research, National Institute for Allergy and Infectious Diseases, National Institutes of Health, 903 S 4th St., Hamilton, MT, 59840, USA
| | - Eric C Dunham
- Laboratory of Virology, Division of Intramural Research, National Institute for Allergy and Infectious Diseases, National Institutes of Health, 903 S 4th St., Hamilton, MT, 59840, USA
| | - Kyle Shifflett
- Laboratory of Virology, Division of Intramural Research, National Institute for Allergy and Infectious Diseases, National Institutes of Health, 903 S 4th St., Hamilton, MT, 59840, USA
| | - Shelby Traeger
- Laboratory of Virology, Division of Intramural Research, National Institute for Allergy and Infectious Diseases, National Institutes of Health, 903 S 4th St., Hamilton, MT, 59840, USA
| | - Anne Leske
- Junior Research Group Arenavirus Biology, Friedrich-Loeffler-Institut, Südufer 10, 17493, Greifswald, Insel Riems, Germany
| | - Eugen Buehler
- Division of Preclinical Innovation, National Center for Advancing Translational Sciences, National Institutes of Health, 31 Center Drive, Bethesda, MD, 20892, USA
| | - Cynthia Martellaro
- Laboratory of Virology, Division of Intramural Research, National Institute for Allergy and Infectious Diseases, National Institutes of Health, 903 S 4th St., Hamilton, MT, 59840, USA
| | - Janine Brandt
- Institute of Molecular Virology and Cell Biology, Friedrich-Loeffler-Institut, Südufer 10, 17493, Greifswald, Insel Riems, Germany
| | - Lisa Wendt
- Institute of Molecular Virology and Cell Biology, Friedrich-Loeffler-Institut, Südufer 10, 17493, Greifswald, Insel Riems, Germany
| | - Andreas Müller
- Institute of Molecular Virology and Cell Biology, Friedrich-Loeffler-Institut, Südufer 10, 17493, Greifswald, Insel Riems, Germany
| | - Stephanie Peitsch
- Institute of Molecular Virology and Cell Biology, Friedrich-Loeffler-Institut, Südufer 10, 17493, Greifswald, Insel Riems, Germany
| | - Sonja M Best
- Laboratory of Virology, Division of Intramural Research, National Institute for Allergy and Infectious Diseases, National Institutes of Health, 903 S 4th St., Hamilton, MT, 59840, USA
| | - Jürgen Stech
- Institute of Molecular Virology and Cell Biology, Friedrich-Loeffler-Institut, Südufer 10, 17493, Greifswald, Insel Riems, Germany
| | - Stefan Finke
- Institute of Molecular Virology and Cell Biology, Friedrich-Loeffler-Institut, Südufer 10, 17493, Greifswald, Insel Riems, Germany
| | - Angela Römer-Oberdörfer
- Institute of Molecular Virology and Cell Biology, Friedrich-Loeffler-Institut, Südufer 10, 17493, Greifswald, Insel Riems, Germany
| | - Allison Groseth
- Laboratory of Virology, Division of Intramural Research, National Institute for Allergy and Infectious Diseases, National Institutes of Health, 903 S 4th St., Hamilton, MT, 59840, USA.,Junior Research Group Arenavirus Biology, Friedrich-Loeffler-Institut, Südufer 10, 17493, Greifswald, Insel Riems, Germany
| | - Heinz Feldmann
- Laboratory of Virology, Division of Intramural Research, National Institute for Allergy and Infectious Diseases, National Institutes of Health, 903 S 4th St., Hamilton, MT, 59840, USA
| | - Thomas Hoenen
- Laboratory of Virology, Division of Intramural Research, National Institute for Allergy and Infectious Diseases, National Institutes of Health, 903 S 4th St., Hamilton, MT, 59840, USA. .,Institute of Molecular Virology and Cell Biology, Friedrich-Loeffler-Institut, Südufer 10, 17493, Greifswald, Insel Riems, Germany.
| |
Collapse
|
40
|
Abstract
Filoviruses are among the most pathogenic viruses known to man, and work with live viruses is restricted to maximum containment laboratories. In order to study individual aspects of the virus life cycle outside of maximum containment laboratories, life cycle modeling systems have been established, which use reporter-encoding miniature versions of the viral genome called minigenomes. With basic minigenome systems viral genome replication and transcription can be studied, whereas more advanced systems also allow us to model other aspects of the virus life cycle outside of a maximum containment laboratory. These systems, therefore, represent powerful tools to study the biology of filoviruses, and for the screening and development of antivirals.
Collapse
Affiliation(s)
- Thomas Hoenen
- Friedrich-Loeffler-Institut, Institute for Molecular Virology and Cell Biology, Greifswald-Isle of Riems, Germany.
| |
Collapse
|
41
|
Abstract
The recently developed Crimean-Congo hemorrhagic fever virus (CCHFV) reverse genetics systems have paved the way for experiments looking to identify and characterize the roles played by viral and cellular proteins in the CCHFV life cycle. In particular, the development of the noninfectious minigenome and virus-like particle (VLP) systems is a tremendous technological advance, as these systems allow for precisely targeting proteins or nucleic acids and measuring the effects these mutations or treatments have on viral life cycle stages. Importantly, these systems can be used at low-containment levels. Presented are the materials and methods currently available to study CCHFV transcription, replication, and translation in the context of a minigenome or VLP.
Collapse
|
42
|
Abstract
In this chapter, we describe the minigenome system for Ebola virus (EBOV), which reconstitutes EBOV polymerase activity in cells and can be used to model viral genome replication and transcription. This protocol comprises all steps including cell culture, plasmid preparation, transfection, and luciferase reporter assay readout.
Collapse
|
43
|
Abstract
Ebolaviruses are the causative agent of a severe hemorrhagic fever with high case fatality rates, for which no approved specific therapy is available. As biosafety level 4 (BSL4) agents, work with live ebolaviruses is restricted to maximum containment laboratories. Transcription and replication-competent viruslike particle (trVLP) systems are reverse genetics-based life cycle modeling systems that allow researchers to model virtually the entire ebolavirus life cycle outside of a maximum containment laboratory. These systems can be used to dissect the virus life cycle, and thus increase our understanding of virus biology, as well as for more applied uses such as the screening and development of novel antivirals, and thus represent powerful tools for work on ebolaviruses.
Collapse
|
44
|
A high throughput screen identifies benzoquinoline compounds as inhibitors of Ebola virus replication. Antiviral Res 2018; 150:193-201. [DOI: 10.1016/j.antiviral.2017.12.019] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2017] [Revised: 12/22/2017] [Accepted: 12/26/2017] [Indexed: 01/28/2023]
|
45
|
Takamatsu Y, Kolesnikova L, Becker S. Ebola virus proteins NP, VP35, and VP24 are essential and sufficient to mediate nucleocapsid transport. Proc Natl Acad Sci U S A 2018; 115:1075-1080. [PMID: 29339477 PMCID: PMC5798334 DOI: 10.1073/pnas.1712263115] [Citation(s) in RCA: 42] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
The intracytoplasmic movement of nucleocapsids is a crucial step in the life cycle of enveloped viruses. Determination of the viral components necessary for viral nucleocapsid transport competency is complicated by the dynamic and complex nature of nucleocapsid assembly and the lack of appropriate model systems. Here, we established a live-cell imaging system based on the ectopic expression of fluorescent Ebola virus (EBOV) fusion proteins, allowing the visualization and analysis of the movement of EBOV nucleocapsid-like structures with different protein compositions. Only three of the five EBOV nucleocapsid proteins-nucleoprotein, VP35, and VP24-were necessary and sufficient to form transport-competent nucleocapsid-like structures. The transport of these structures was found to be dependent on actin polymerization and to have dynamics that were undistinguishable from those of nucleocapsids in EBOV-infected cells. The intracytoplasmic movement of nucleocapsid-like structures was completely independent of the viral matrix protein VP40 and the viral surface glycoprotein GP. However, VP40 greatly enhanced the efficiency of nucleocapsid recruitment into filopodia, the sites of EBOV budding.
Collapse
Affiliation(s)
- Yuki Takamatsu
- Institute of Virology, Faculty of Medicine, Philipps University Marburg, 35037 Marburg, Germany
| | - Larissa Kolesnikova
- Institute of Virology, Faculty of Medicine, Philipps University Marburg, 35037 Marburg, Germany
| | - Stephan Becker
- Institute of Virology, Faculty of Medicine, Philipps University Marburg, 35037 Marburg, Germany;
- Thematic Translational Unit Emerging Infections, German Center of Infection Research (DZIF), 35037 Marburg, Germany
| |
Collapse
|
46
|
|
47
|
Novel Stable Ebola Virus Minigenome Replicon Reveals Remarkable Stability of the Viral Genome. J Virol 2017; 91:JVI.01316-17. [PMID: 28878087 DOI: 10.1128/jvi.01316-17] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2017] [Accepted: 09/04/2017] [Indexed: 12/14/2022] Open
Abstract
Ebola virus (EBOV) causes severe hemorrhagic fever in humans and other primates with a high case fatality rate. No approved drug or vaccine of EBOV is available, which necessitates better understanding of the virus life cycle. Studies on EBOV have been hampered because experimentations involving live virus are restricted to biosafety level 4 (BSL4) laboratories. The EBOV minigenome system has provided researchers with the opportunity to study EBOV under BSL2 conditions. Here, we developed a novel EBOV minigenome replicon which, to our knowledge, is the first EBOV cell culture system that can stably replicate and transcribe the EBOV minigenome. The minigenomic RNA harboring a Gaussia luciferase and hygromycin-resistant marker can replicate for months in a helper cell stably expressing viral nucleoprotein (NP), viral protein 35 (VP35), VP30, and L proteins. Quantification of viral RNA (vRNA), cRNA, and mRNA levels of the EBOV minigenome demonstrated that the stable EBOV replicon had much-more-active minigenome replication than previously developed transient-transfection-based EBOV minigenome systems, which recapitulate viral primary transcription more than genome replication. Interestingly, minigenome replication in the stable EBOV replicon cells was insensitive to interferon treatment or RNA interference. Moreover, RNase digestion of the replicon cell lysates revealed the remarkably stable nature of the EBOV minigenomic vRNA ribonucleoprotein complex, which may help improve understanding of EBOV persistence in convalescent patients.IMPORTANCE The scope and severity of the recent Ebola outbreak in Western Africa justified a more comprehensive investigation of the causative risk group 4 agent Ebola virus (EBOV). Study of EBOV replication and antiviral development can be facilitated by developing a cell culture system that allows experimentation under biosafety level 2 conditions. Here, we developed a novel stable EBOV minigenome replicon which, to our knowledge, is the first EBOV cell culture system that can stably replicate and transcribe the EBOV minigenome. The replicon system had more-active genome replication than previously developed transient-transfection-based EBOV minigenome systems, providing a convenient surrogate system to study EBOV replication. Furthermore, self-replicating minigenomic vRNA in the replicon cells displayed strong stability in response to interferon treatment, RNA silencing, and RNase digestion, which may provide an explanation for the persistence of EBOV in survivors.
Collapse
|
48
|
Schmidt ML, Hoenen T. Characterization of the catalytic center of the Ebola virus L polymerase. PLoS Negl Trop Dis 2017; 11:e0005996. [PMID: 28991917 PMCID: PMC5648267 DOI: 10.1371/journal.pntd.0005996] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2017] [Revised: 10/19/2017] [Accepted: 09/27/2017] [Indexed: 01/02/2023] Open
Abstract
Background Ebola virus (EBOV) causes a severe hemorrhagic fever in humans and non-human primates. While no licensed therapeutics are available, recently there has been tremendous progress in developing antivirals. Targeting the ribonucleoprotein complex (RNP) proteins, which facilitate genome replication and transcription, and particularly the polymerase L, is a promising antiviral approach since these processes are essential for the virus life cycle. However, until now little is known about L in terms of its structure and function, and in particular the catalytic center of the RNA-dependent RNA polymerase (RdRp) of L, which is one of the most promising molecular targets, has never been experimentally characterized. Methodology/Principal findings Using multiple sequence alignments with other negative sense single-stranded RNA viruses we identified the putative catalytic center of the EBOV RdRp. An L protein with mutations in this center was then generated and characterized using various life cycle modelling systems. These systems are based on minigenomes, i.e. miniature versions of the viral genome, in which the viral genes are exchanged against a reporter gene. When such minigenomes are coexpressed with RNP proteins in mammalian cells, the RNP proteins recognize them as authentic templates for replication and transcription, resulting in reporter activity reflecting these processes. Replication-competent minigenome systems indicated that our L catalytic domain mutant was impaired in genome replication and/or transcription, and by using replication-deficient minigenome systems, as well as a novel RT-qPCR-based genome replication assay, we showed that it indeed no longer supported either of these processes. However, it still showed similar expression to wild-type L, and retained its ability to be incorporated into inclusion bodies, which are the sites of EBOV genome replication. Conclusions/Significance We have experimentally defined the catalytic center of the EBOV RdRp, and thus a promising antiviral target regulating an essential aspect of the EBOV life cycle. Ebola viruses cause severe hemorrhagic fevers, and were responsible for the devastating Ebola virus disease epidemic in West Africa from 2013 to 2016. While a number of experimental therapeutics against these viruses target the viral polymerase, there are still significant gaps in our knowledge regarding this essential viral protein. In particular, until now no experimental evidence has been provided identifying the catalytic center of the viral RNA-dependent RNA polymerase, which is absolutely essential for the virus life cycle due to its role in replicating and transcribing the viral negative-sense RNA genome. Based on a comparison to related negative-sense RNA viruses from other virus families we identified a putative catalytic center within the Ebola virus polymerase, and provide the experimental evidence that the Ebola virus polymerase indeed utilizes a classical GDNQ motif for both genome replication and transcription. This finding not only increases our knowledge regarding the molecular biology of Ebola viruses, but also defines a molecular target for the development of antivirals against this deadly virus.
Collapse
Affiliation(s)
- Marie Luisa Schmidt
- Institute for Molecular Virology and Cell Biology, Friedrich-Loeffler-Institut, Greifswald–Insel Riems, Germany
| | - Thomas Hoenen
- Institute for Molecular Virology and Cell Biology, Friedrich-Loeffler-Institut, Greifswald–Insel Riems, Germany
- * E-mail:
| |
Collapse
|
49
|
An RNA polymerase II-driven Ebola virus minigenome system as an advanced tool for antiviral drug screening. Antiviral Res 2017; 146:21-27. [PMID: 28807685 DOI: 10.1016/j.antiviral.2017.08.005] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2017] [Revised: 08/08/2017] [Accepted: 08/09/2017] [Indexed: 11/20/2022]
Abstract
Ebola virus (EBOV) causes a severe disease in humans with the potential for significant international public health consequences. Currently, treatments are limited to experimental vaccines and therapeutics. Therefore, research into prophylaxis and antiviral strategies to combat EBOV infections is of utmost importance. The requirement for high containment laboratories to study EBOV infection is a limiting factor for conducting EBOV research. To overcome this issue, minigenome systems have been used as valuable tools to study EBOV replication and transcription mechanisms and to screen for antiviral compounds at biosafety level 2. The most commonly used EBOV minigenome system relies on the ectopic expression of the T7 RNA polymerase (T7), which can be limiting for certain cell types. We have established an improved EBOV minigenome system that utilizes endogenous RNA polymerase II (pol II) as a driver for the synthesis of minigenome RNA. We show here that this system is as efficient as the T7-based minigenome system, but works in a wider range of cell types, including biologically relevant cell types such as bat cells. Importantly, we were also able to adapt this system to a reliable and cost-effective 96-well format antiviral screening assay with a Z-factor of 0.74, indicative of a robust assay. Using this format, we identified JG40, an inhibitor of Hsp70, as an inhibitor of EBOV replication, highlighting the potential for this system as a tool for antiviral drug screening. In summary, this updated EBOV minigenome system provides a convenient and effective means of advancing the field of EBOV research.
Collapse
|
50
|
Liang J, Jangra RK, Bollinger L, Wada J, Radoshitzky SR, Chandran K, Jahrling PB, Kuhn JH, Jensen KS. Candidate medical countermeasures targeting Ebola virus cell entry. Future Virol 2017. [DOI: 10.2217/fvl-2016-0113] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Medical countermeasures (MCMs) against virus infections ideally prevent the adsorption or entry of virions into target cells, thereby circumventing infection. Recent significant advances in elucidating the mechanism of Ebola virus (EBOV) host-cell penetration include the involvement of two-pore channels at the early stage of entry, and identification of cellular proteases for EBOV spike glycoprotein maturation and the intracellular EBOV receptor, Niemann–Pick type C1. This improved understanding of the initial steps of EBOV infection is now increasingly applied to rapid development of candidate MCMs, some of which have already entered the clinic. Candidate MCMs discussed include antibodies, small molecules and peptides that target various stages of the described EBOV cell-entry pathway. In this review, we summarize the currently known spectrum of EBOV cell-entry inhibitors, describe their mechanism of action and evaluate their potential for future development.
Collapse
Affiliation(s)
- Janie Liang
- Integrated Research Facility at Fort Detrick, National Institute of Allergy & Infectious Diseases, National Institutes of Health, Fort Detrick, Frederick, MD, USA
| | - Rohit K Jangra
- Department of Microbiology & Immunology, Albert Einstein College of Medicine, Bronx, NY, USA
| | - Laura Bollinger
- Integrated Research Facility at Fort Detrick, National Institute of Allergy & Infectious Diseases, National Institutes of Health, Fort Detrick, Frederick, MD, USA
| | - Jiro Wada
- Integrated Research Facility at Fort Detrick, National Institute of Allergy & Infectious Diseases, National Institutes of Health, Fort Detrick, Frederick, MD, USA
| | - Sheli R Radoshitzky
- United States Army Medical Research Institute of Infectious Diseases, Fort Detrick, Frederick, MD, USA
| | - Kartik Chandran
- Department of Microbiology & Immunology, Albert Einstein College of Medicine, Bronx, NY, USA
| | - Peter B Jahrling
- Integrated Research Facility at Fort Detrick, National Institute of Allergy & Infectious Diseases, National Institutes of Health, Fort Detrick, Frederick, MD, USA
| | - Jens H Kuhn
- Integrated Research Facility at Fort Detrick, National Institute of Allergy & Infectious Diseases, National Institutes of Health, Fort Detrick, Frederick, MD, USA
| | - Kenneth S Jensen
- Integrated Research Facility at Fort Detrick, National Institute of Allergy & Infectious Diseases, National Institutes of Health, Fort Detrick, Frederick, MD, USA
| |
Collapse
|