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Wiśniewski M, Babirye P, Musubika C, Papakonstantinou E, Kirimunda S, Łaźniewski M, Szczepińska T, Joloba ML, Eliopoulos E, Bongcam-Rudloff E, Vlachakis D, Kumar Halder A, Plewczyński D, Wayengera M. Use of in silico approaches, synthesis and profiling of Pan-filovirus GP-1,2 preprotein specific antibodies. Brief Funct Genomics 2024:elae012. [PMID: 38605526 DOI: 10.1093/bfgp/elae012] [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: 12/28/2023] [Revised: 03/15/2024] [Accepted: 03/22/2024] [Indexed: 04/13/2024] Open
Abstract
Intermolecular interactions of protein-protein complexes play a principal role in the process of discovering new substances used in the diagnosis and treatment of many diseases. Among such complexes of proteins, we have to mention antibodies; they interact with specific antigens of two genera of single-stranded RNA viruses belonging to the family Filoviridae-Ebolavirus and Marburgvirus; both cause rare but fatal viral hemorrhagic fever in Africa, with pandemic potential. In this research, we conduct studies aimed at the design and evaluation of antibodies targeting the filovirus glycoprotein precursor GP-1,2 to develop potential targets for the pan-filovirus easy-to-use rapid diagnostic tests. The in silico research using the available 3D structure of the natural antibody-antigen complex was carried out to determine the stability of individual protein segments in the process of its formation and maintenance. The computed free binding energy of the complex and its decomposition for all amino acids allowed us to define the residues that play an essential role in the structure and indicated the spots where potential antibodies can be improved. Following that, the study involved targeting six epitopes of the filovirus GP1,2 with two polyclonal antibodies (pABs) and 14 monoclonal antibodies (mABs). The evaluation conducted using Enzyme Immunoassays tested 62 different sandwich combinations of monoclonal antibodies (mAbs), identifying 10 combinations that successfully captured the recombinant GP1,2 (rGP). Among these combinations, the sandwich option (3G2G12* - (rGP) - 2D8F11) exhibited the highest propensity for capturing the rGP antigen.
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Affiliation(s)
- Maciej Wiśniewski
- Laboratory of Functional and Structural Genomics, Centre of New Technologies, University of Warsaw, Banacha 2c, 02-097, Warsaw, Poland
| | - Peace Babirye
- Department of Immunology and Molecular Biology, School of Biomedical Sciences, College of Health Sciences, Makerere University, Old Mulago Hill Road P.O. Box 7072, Kampala, Uganda
| | - Carol Musubika
- Department of Immunology and Molecular Biology, School of Biomedical Sciences, College of Health Sciences, Makerere University, Old Mulago Hill Road P.O. Box 7072, Kampala, Uganda
| | - Eleni Papakonstantinou
- Genetics Laboratory, Biotechnology Department, School of Applied Biology and Biotechnology,Agricultural University of Athens, Iera Odos 7511855 Athens, Greece
| | - Samuel Kirimunda
- Department of Immunology and Molecular Biology, School of Biomedical Sciences, College of Health Sciences, Makerere University, Old Mulago Hill Road P.O. Box 7072, Kampala, Uganda
| | - Michal Łaźniewski
- Laboratory of Functional and Structural Genomics, Centre of New Technologies, University of Warsaw, Banacha 2c, 02-097, Warsaw, Poland
| | - Teresa Szczepińska
- Laboratory of Functional and Structural Genomics, Centre of New Technologies, University of Warsaw, Banacha 2c, 02-097, Warsaw, Poland
| | - Moses L Joloba
- Department of Immunology and Molecular Biology, School of Biomedical Sciences, College of Health Sciences, Makerere University, Old Mulago Hill Road P.O. Box 7072, Kampala, Uganda
| | - Elias Eliopoulos
- Genetics Laboratory, Biotechnology Department, School of Applied Biology and Biotechnology,Agricultural University of Athens, Iera Odos 7511855 Athens, Greece
| | - Erik Bongcam-Rudloff
- Department of Animal Breeding and Genetics, Bioinformatics section, Swedish University for Agricultural Sciences, Ulls väg 26, PO Box 7023, S-750 07 Uppsala, Sweden
| | - Dimitrios Vlachakis
- Genetics Laboratory, Biotechnology Department, School of Applied Biology and Biotechnology, Agricultural University of Athens, Iera Odos 7511855 Athens, Greece
| | - Anup Kumar Halder
- Laboratory of Functional and Structural Genomics, Centre of New Technologies, University of Warsaw, Banacha 2c, 02-097, Warsaw, Poland
- Laboratory of Bioinformatics and Computational Genomics, Faculty of Mathematics and Information Science, Warsaw University of Technology, Koszykowa 75, 00-662, Warsaw, Poland
| | - Dariusz Plewczyński
- Laboratory of Functional and Structural Genomics, Centre of New Technologies, University of Warsaw, Banacha 2c, 02-097, Warsaw, Poland
- Laboratory of Bioinformatics and Computational Genomics, Faculty of Mathematics and Information Science, Warsaw University of Technology, Koszykowa 75, 00-662, Warsaw, Poland
| | - Misaki Wayengera
- Department of Immunology and Molecular Biology, School of Biomedical Sciences, College of Health Sciences, Makerere University, Old Mulago Hill Road P.O. Box 7072, Kampala, Uganda
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Zhang Y, Zhang M, Wu H, Wang X, Zheng H, Feng J, Wang J, Luo L, Xiao H, Qiao C, Li X, Zheng Y, Huang W, Wang Y, Wang Y, Shi Y, Feng J, Chen G. A novel MARV glycoprotein-specific antibody with potentials of broad-spectrum neutralization to filovirus. eLife 2024; 12:RP91181. [PMID: 38526940 PMCID: PMC10963030 DOI: 10.7554/elife.91181] [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] [Indexed: 03/27/2024] Open
Abstract
Marburg virus (MARV) is one of the filovirus species that cause deadly hemorrhagic fever in humans, with mortality rates up to 90%. Neutralizing antibodies represent ideal candidates to prevent or treat virus disease. However, no antibody has been approved for MARV treatment to date. In this study, we identified a novel human antibody named AF-03 that targeted MARV glycoprotein (GP). AF-03 possessed a high binding affinity to MARV GP and showed neutralizing and protective activities against the pseudotyped MARV in vitro and in vivo. Epitope identification, including molecular docking and experiment-based analysis of mutated species, revealed that AF-03 recognized the Niemann-Pick C1 (NPC1) binding domain within GP1. Interestingly, we found the neutralizing activity of AF-03 to pseudotyped Ebola viruses (EBOV, SUDV, and BDBV) harboring cleaved GP instead of full-length GP. Furthermore, NPC2-fused AF-03 exhibited neutralizing activity to several filovirus species and EBOV mutants via binding to CI-MPR. In conclusion, this work demonstrates that AF-03 represents a promising therapeutic cargo for filovirus-caused disease.
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Affiliation(s)
- Yuting Zhang
- State Key Laboratory of Toxicology and Medical Countermeasures, Institute of Pharmacology and ToxicologyBeijingChina
- Inner Mongolia Key Lab of Molecular Biology, School of Basic Medical Sciences, Inner Mongolia Medical UniversityHohhotChina
| | - Min Zhang
- State Key Laboratory of Toxicology and Medical Countermeasures, Institute of Pharmacology and ToxicologyBeijingChina
| | - Haiyan Wu
- State Key Laboratory of Toxicology and Medical Countermeasures, Institute of Pharmacology and ToxicologyBeijingChina
| | - Xinwei Wang
- State Key Laboratory of Toxicology and Medical Countermeasures, Institute of Pharmacology and ToxicologyBeijingChina
- Inner Mongolia Key Lab of Molecular Biology, School of Basic Medical Sciences, Inner Mongolia Medical UniversityHohhotChina
| | - Hang Zheng
- State Key Laboratory of Toxicology and Medical Countermeasures, Institute of Pharmacology and ToxicologyBeijingChina
- Inner Mongolia Key Lab of Molecular Biology, School of Basic Medical Sciences, Inner Mongolia Medical UniversityHohhotChina
| | - Junjuan Feng
- State Key Laboratory of Toxicology and Medical Countermeasures, Institute of Pharmacology and ToxicologyBeijingChina
- Inner Mongolia Key Lab of Molecular Biology, School of Basic Medical Sciences, Inner Mongolia Medical UniversityHohhotChina
| | - Jing Wang
- State Key Laboratory of Toxicology and Medical Countermeasures, Institute of Pharmacology and ToxicologyBeijingChina
| | - Longlong Luo
- State Key Laboratory of Toxicology and Medical Countermeasures, Institute of Pharmacology and ToxicologyBeijingChina
| | - He Xiao
- State Key Laboratory of Toxicology and Medical Countermeasures, Institute of Pharmacology and ToxicologyBeijingChina
| | - Chunxia Qiao
- State Key Laboratory of Toxicology and Medical Countermeasures, Institute of Pharmacology and ToxicologyBeijingChina
| | - Xinying Li
- State Key Laboratory of Toxicology and Medical Countermeasures, Institute of Pharmacology and ToxicologyBeijingChina
| | - Yuanqiang Zheng
- Inner Mongolia Key Lab of Molecular Biology, School of Basic Medical Sciences, Inner Mongolia Medical UniversityHohhotChina
| | - Weijin Huang
- Division of HIV/AIDS and Sex-transmitted Virus Vaccines, National Institutes for Food and Drug ControlBeijingChina
| | - Youchun Wang
- Division of HIV/AIDS and Sex-transmitted Virus Vaccines, National Institutes for Food and Drug ControlBeijingChina
| | - Yi Wang
- Department of Hematology, Fifth Medical Center of Chinese PLA General HospitalBeijingChina
| | - Yanchun Shi
- Inner Mongolia Key Lab of Molecular Biology, School of Basic Medical Sciences, Inner Mongolia Medical UniversityHohhotChina
| | - Jiannan Feng
- State Key Laboratory of Toxicology and Medical Countermeasures, Institute of Pharmacology and ToxicologyBeijingChina
| | - Guojiang Chen
- State Key Laboratory of Toxicology and Medical Countermeasures, Institute of Pharmacology and ToxicologyBeijingChina
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Mehedi M, Ricklefs S, Takada A, Sturdevant D, Porcella SF, Marzi A, Feldmann H. RNA Editing as a General Trait of Ebolaviruses. J Infect Dis 2023; 228:S498-S507. [PMID: 37348869 PMCID: PMC10651210 DOI: 10.1093/infdis/jiad228] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2023] [Revised: 06/06/2023] [Accepted: 06/20/2023] [Indexed: 06/24/2023] Open
Abstract
RNA editing has been discovered as an essential mechanism for the transcription of the glycoprotein (GP) gene of Ebola virus but not Marburg virus. We developed a rapid transcript quantification assay (RTQA) to analyze RNA transcripts generated through RNA editing and used immunoblotting with a pan-ebolavirus monoclonal antibody to confirm different GP gene-derived products. RTQA successfully quantified GP gene transcripts during infection with representative members of 5 ebolavirus species. Immunoblotting verified expression of the soluble GP and the transmembrane GP. Our results defined RNA editing as a general trait of ebolaviruses. The degree of editing, however, varies among ebolaviruses with Reston virus showing the lowest and Bundibugyo virus the highest degree of editing.
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Affiliation(s)
| | - Stacy Ricklefs
- Genomics Unit, Research Technology Branch, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, Montana
| | - Ayato Takada
- Division of Global Epidemiology, International Institute for Zoonosis Control, Hokkaido University, Sapporo, Japan
| | - Dan Sturdevant
- Genomics Unit, Research Technology Branch, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, Montana
| | - Stephen F Porcella
- Genomics Unit, Research Technology Branch, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, Montana
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Petersen M, Lotke R, Hopfensperger K, Victoria S, Haußmann I, Burster T, Baldauf HM, Sauter D. Inhibition of Infectious HIV-1 Production by Rerouting the Cellular Furin Inhibitor Serpin B8. J Virol 2023; 97:e0029423. [PMID: 37272794 PMCID: PMC10308892 DOI: 10.1128/jvi.00294-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2023] [Accepted: 05/17/2023] [Indexed: 06/06/2023] Open
Abstract
Serpins are a superfamily of proteins that regulate a variety of physiological processes by irreversibly inhibiting the enzymatic activity of different serine proteases. For example, Serpin Family B Member 8 (Serpin B8, also known as PI8 and CAP2) binds to and inhibits the proprotein convertase furin. Like many other viral pathogens, human immunodeficiency virus type 1 (HIV-1) exploits furin for the proteolytic activation of its envelope glycoprotein (Env). Since the furin inhibitor Serpin B8 is expressed in primary target cells of HIV-1 and induced under inflammatory conditions, we hypothesized that it might interfere with HIV-1 Env maturation and decrease infectivity of newly produced virions. Indeed, recombinant Serpin B8 reduced furin-mediated cleavage of an HIV-1 Env reporter substrate in vitro. However, Serpin B8 did not affect Env maturation or reduce HIV-1 particle infectivity when expressed in HIV-1-producing cells. Immunofluorescence imaging, dimerization assays and in silico sequence analyses revealed that Serpin B8 failed to inhibit intracellular furin since both proteins localized to different subcellular compartments. We therefore aimed at rendering Serpin B8 active against HIV-1 by relocalizing it to furin-containing secretory compartments. Indeed, the addition of a heterologous signal peptide conferred potent anti-HIV-1 activity to Serpin B8 and significantly decreased infectivity of newly produced viral particles. Thus, our findings demonstrate that subcellular relocalization of a cellular protease inhibitor can result in efficient inhibition of infectious HIV-1 production. IMPORTANCE Many cellular proteases serve as dependency factors during viral infection and are hijacked by viruses for the maturation of their own (glyco)proteins. Consequently, inhibition of these cellular proteases may represent a means to inhibit the spread of viral infection. For example, several studies have investigated the serine protease furin as a potential therapeutic target since this protease cleaves and activates several viral envelope proteins, including HIV-1 Env. Besides the development of small molecule inhibitors, cell-intrinsic protease inhibitors may also be exploited to advance current antiviral treatment approaches. Here, we show that Serpin B8, an endogenous furin inhibitor, can inhibit HIV-1 Env maturation and efficiently reduce infectious HIV-1 production when rerouted to the secretory pathway. The results of our study not only provide important insights into the biology of Serpins, but also show how protein engineering of an endogenous furin inhibitor can render it active against HIV-1.
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Affiliation(s)
- Moritz Petersen
- Institute for Medical Virology and Epidemiology of Viral Diseases, University Hospital Tübingen, Tübingen, Germany
| | - Rishikesh Lotke
- Institute for Medical Virology and Epidemiology of Viral Diseases, University Hospital Tübingen, Tübingen, Germany
| | - Kristina Hopfensperger
- Institute for Medical Virology and Epidemiology of Viral Diseases, University Hospital Tübingen, Tübingen, Germany
| | - Sabina Victoria
- Institute for Medical Virology and Epidemiology of Viral Diseases, University Hospital Tübingen, Tübingen, Germany
| | - Isabell Haußmann
- Institute for Medical Virology and Epidemiology of Viral Diseases, University Hospital Tübingen, Tübingen, Germany
| | - Timo Burster
- School of Sciences and Humanities, Nazarbayev University, Astana, Kazakhstan
| | - Hanna-Mari Baldauf
- Max von Pettenkofer Institute and Gene Center, Virology, National Reference Center for Retroviruses, Faculty of Medicine, LMU Munich, Munich, Germany
| | - Daniel Sauter
- Institute for Medical Virology and Epidemiology of Viral Diseases, University Hospital Tübingen, Tübingen, Germany
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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.
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6
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Rohde C, Pfeiffer S, Baumgart S, Becker S, Krähling V. Ebola Virus Activates IRE1α-Dependent XBP1u Splicing. Viruses 2022; 15:122. [PMID: 36680162 PMCID: PMC9863596 DOI: 10.3390/v15010122] [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: 11/29/2022] [Revised: 12/22/2022] [Accepted: 12/29/2022] [Indexed: 01/04/2023] Open
Abstract
Ebola (EBOV) and Marburg virus (MARV) are highly pathogenic filoviruses that influence cellular signaling according to their own needs. MARV has been shown to regulate the IRE1α-dependent unfolded protein response (UPR) to ensure optimal virus replication. It was not known whether EBOV affects this signaling cascade, which can be beneficial or detrimental for viruses. Activation of IRE1α leads to the expression of the transcription factor XBP1s, which binds to cis-acting UPR elements (UPRE), resulting in the expression of genes aimed at restoring homeostasis in the endoplasmic reticulum. We observed that EBOV infection, in contrast to MARV infection, led to UPR activation by IRE1α-dependent but not ATF6-dependent signaling. We showed an activation of IRE1α, XBP1s and UPRE target genes upon EBOV infection. ATF6, another UPRE transcription factor, was not activated. UPRE activation was mainly attributed to the EBOV nucleoprotein NP and the soluble glycoprotein sGP. Finally, activation of UPR by thapsigargin, a potent ER-stress inducer, in parallel to infection as well as knock-out of XBP1 had no effect on EBOV growth, while MARV proliferation was affected by thapsigargin-dependent UPR activation. Taken together EBOV and MARV differ in their strategy of balancing IRE1α-dependent signaling for their own needs.
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Affiliation(s)
- Cornelius Rohde
- Institute of Virology, Philipps University Marburg, 35043 Marburg, Germany
- German Center for Infection Research (DZIF), Partner Site Gießen–Marburg–Langen, 35043 Marburg, Germany
| | - Sebastian Pfeiffer
- Institute of Virology, Philipps University Marburg, 35043 Marburg, Germany
| | - Sara Baumgart
- Institute of Virology, Philipps University Marburg, 35043 Marburg, Germany
- German Center for Infection Research (DZIF), Partner Site Gießen–Marburg–Langen, 35043 Marburg, Germany
| | - Stephan Becker
- Institute of Virology, Philipps University Marburg, 35043 Marburg, Germany
- German Center for Infection Research (DZIF), Partner Site Gießen–Marburg–Langen, 35043 Marburg, Germany
| | - Verena Krähling
- Institute of Virology, Philipps University Marburg, 35043 Marburg, Germany
- German Center for Infection Research (DZIF), Partner Site Gießen–Marburg–Langen, 35043 Marburg, Germany
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Zhang Y, Zhang L, Wu J, Yu Y, Liu S, Li T, Li Q, Ding R, Wang H, Nie J, Cui Z, Wang Y, Huang W, Wang Y. A second functional furin site in the SARS-CoV-2 spike protein. Emerg Microbes Infect 2022; 11:182-194. [PMID: 34856891 PMCID: PMC8741242 DOI: 10.1080/22221751.2021.2014284] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
The ubiquitously-expressed proteolytic enzyme furin is closely related to the pathogenesis of SARS-CoV-2 and therefore represents a key target for antiviral therapy. Based on bioinformatic analysis and pseudovirus tests, we discovered a second functional furin site located in the spike protein. Furin still increased the infectivity of mutated SARS-CoV-2 pseudovirus in 293T-ACE2 cells when the canonical polybasic cleavage site (682-686) was deleted. However, K814A mutation eliminated the enhancing effect of furin on virus infection. Furin inhibitor prevented infection by 682-686-deleted SARS-CoV-2 in 293T-ACE2-furin cells, but not the K814A mutant. K814A mutation did not affect the activity of TMPRSS2 and cathepsin L but did impact the cleavage of S2 into S2' and cell-cell fusion. Additionally, we showed that this functional furin site exists in RaTG13 from bat and PCoV-GD/GX from pangolin. Therefore, we discovered a new functional furin site that is pivotal in promoting SARS-CoV-2 infection.
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Affiliation(s)
- Yue Zhang
- Division of HIV/AIDS and Sex-transmitted Virus Vaccines, Institute for Biological Product Control, National Institutes for Food and Drug Control (NIFDC), Beijing, People's Republic of China
- National Vaccine & Serum Institute, Beijing, People's Republic of China
| | - Li Zhang
- Division of HIV/AIDS and Sex-transmitted Virus Vaccines, Institute for Biological Product Control, National Institutes for Food and Drug Control (NIFDC), Beijing, People's Republic of China
| | - Jiajing Wu
- Division of HIV/AIDS and Sex-transmitted Virus Vaccines, Institute for Biological Product Control, National Institutes for Food and Drug Control (NIFDC), Beijing, People's Republic of China
| | - Yuanling Yu
- Division of HIV/AIDS and Sex-transmitted Virus Vaccines, Institute for Biological Product Control, National Institutes for Food and Drug Control (NIFDC), Beijing, People's Republic of China
| | - Shuo Liu
- Division of HIV/AIDS and Sex-transmitted Virus Vaccines, Institute for Biological Product Control, National Institutes for Food and Drug Control (NIFDC), Beijing, People's Republic of China
| | - Tao Li
- Division of HIV/AIDS and Sex-transmitted Virus Vaccines, Institute for Biological Product Control, National Institutes for Food and Drug Control (NIFDC), Beijing, People's Republic of China
| | - Qianqian Li
- Division of HIV/AIDS and Sex-transmitted Virus Vaccines, Institute for Biological Product Control, National Institutes for Food and Drug Control (NIFDC), Beijing, People's Republic of China
| | - Ruxia Ding
- Division of HIV/AIDS and Sex-transmitted Virus Vaccines, Institute for Biological Product Control, National Institutes for Food and Drug Control (NIFDC), Beijing, People's Republic of China
| | - Haixin Wang
- Division of HIV/AIDS and Sex-transmitted Virus Vaccines, Institute for Biological Product Control, National Institutes for Food and Drug Control (NIFDC), Beijing, People's Republic of China
| | - Jianhui Nie
- Division of HIV/AIDS and Sex-transmitted Virus Vaccines, Institute for Biological Product Control, National Institutes for Food and Drug Control (NIFDC), Beijing, People's Republic of China
| | - Zhimin Cui
- Division of HIV/AIDS and Sex-transmitted Virus Vaccines, Institute for Biological Product Control, National Institutes for Food and Drug Control (NIFDC), Beijing, People's Republic of China
| | - Yulin Wang
- National Vaccine & Serum Institute, Beijing, People's Republic of China
| | - Weijin Huang
- Division of HIV/AIDS and Sex-transmitted Virus Vaccines, Institute for Biological Product Control, National Institutes for Food and Drug Control (NIFDC), Beijing, People's Republic of China
| | - Youchun Wang
- Division of HIV/AIDS and Sex-transmitted Virus Vaccines, Institute for Biological Product Control, National Institutes for Food and Drug Control (NIFDC), Beijing, People's Republic of China
- Lead Contact
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Baral P, Pavadai E, Zhou Z, Xu Y, Tison CK, Pokhrel R, Gerstman BS, Chapagain PP. Immunoinformatic screening of Marburgvirus epitopes and computational investigations of epitope-allele complexes. Int Immunopharmacol 2022; 111:109109. [PMID: 35926269 DOI: 10.1016/j.intimp.2022.109109] [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: 03/22/2022] [Revised: 06/14/2022] [Accepted: 07/27/2022] [Indexed: 11/17/2022]
Abstract
Marburgvirus (MARV), a member of the Filovirus family, causes severe hemorrhagic fever in humans. Currently, there are no approved vaccines or post exposure treatment methods available against MARV. With the aim of identifying vaccine candidates against MARV, we employ different sequence-based computational methods to predict the MHC-I and MHC-II T-cell epitopes as well as B-cell epitopes for the complete MARV genome. We analyzed the variations in the predicted epitopes among four MARV variants, the Lake Victoria, Angola, Musoke, and Ravn. We used a consensus approach to identify several epitopes, including novel epitopes, and narrowed down the selection based on different parameters such as antigenicity and IC50 values. The selected epitopes can be used in various vaccine constructs that give effective antibody responses. The MHC-I epitope-allele complexes for GP and NP with favorably low IC50 values were investigated using molecular dynamics computations to determine the molecular details of the epitope-allele complexes. This study provides information for further experimental validation of the potential epitopes and the design and development of MARV vaccines.
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Affiliation(s)
- Prabin Baral
- Department of Physics, Florida International University, Miami, FL 33199, USA
| | - Elumalai Pavadai
- Department of Physics, Florida International University, Miami, FL 33199, USA
| | - Ziyou Zhou
- Biotech Group, Luna Labs USA, Charlottesville, VA 22903, USA
| | - Yang Xu
- Biotech Group, Luna Labs USA, Charlottesville, VA 22903, USA
| | | | - Rudramani Pokhrel
- Department of Physics, Florida International University, Miami, FL 33199, USA
| | - Bernard S Gerstman
- Department of Physics, Florida International University, Miami, FL 33199, USA; Biomolecular Sciences Institute, Florida International University, Miami, FL 33199, USA
| | - Prem P Chapagain
- Department of Physics, Florida International University, Miami, FL 33199, USA; Biomolecular Sciences Institute, Florida International University, Miami, FL 33199, USA.
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Yu X, Saphire EO. Development and Structural Analysis of Antibody Therapeutics for Filoviruses. Pathogens 2022; 11:pathogens11030374. [PMID: 35335698 PMCID: PMC8949092 DOI: 10.3390/pathogens11030374] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2022] [Revised: 03/16/2022] [Accepted: 03/17/2022] [Indexed: 11/16/2022] Open
Abstract
The filoviruses, including ebolaviruses and marburgviruses, are among the world’s deadliest pathogens. As the only surface-exposed protein on mature virions, their glycoprotein GP is the focus of current therapeutic monoclonal antibody discovery efforts. With recent technological developments, potent antibodies have been identified from immunized animals and human survivors of virus infections and have been characterized functionally and structurally. Structural insight into how the most successful antibodies target GP further guides vaccine development. Here we review the recent developments in the identification and characterization of neutralizing antibodies and cocktail immunotherapies.
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Affiliation(s)
- Xiaoying Yu
- Center for Infectious Disease and Vaccine Discovery, La Jolla Institute for Immunology, 9420 Athena Circle, La Jolla, CA 92037, USA;
| | - Erica Ollmann Saphire
- Center for Infectious Disease and Vaccine Discovery, La Jolla Institute for Immunology, 9420 Athena Circle, La Jolla, CA 92037, USA;
- Department of Medicine, University of California, San Diego, La Jolla, CA 92093, USA
- Correspondence: ; Tel.: +1-858-752-6791
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Bioinformatics Analysis of Allele Frequencies and Expression Patterns of ACE2, TMPRSS2 and FURIN in Different Populations and Susceptibility to SARS-CoV-2. Genes (Basel) 2021; 12:genes12071041. [PMID: 34356057 PMCID: PMC8303858 DOI: 10.3390/genes12071041] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2021] [Revised: 05/18/2021] [Accepted: 06/02/2021] [Indexed: 02/07/2023] Open
Abstract
The virus responsible for the COVID-19 global health crisis, SARS-CoV-2, has been shown to utilize the ACE2 protein as an entry point to its target cells. The virus has been shown to rely on the actions of TMPRSS2 (a serine protease), as well as FURIN (a peptidase), for the critical priming of its spike protein. It has been postulated that variations in the sequence and expression of SARS-CoV-2's receptor (ACE2) and the two priming proteases (TMPRSS2 and FURIN) may be critical in contributing to SARS-CoV-2 infectivity. This study aims to examine the different expression levels of FURIN in various tissues and age ranges in light of ACE2 and TMPRSS2 expression levels using the LungMAP database. Furthermore, we retrieved expression quantitative trait loci (eQTLs) of the three genes and their annotation. We analyzed the frequency of the retrieved variants in data from various populations and compared it to the Egyptian population. We highlight FURIN's potential interplay with the immune response to SARS-CoV-2 and showcase a myriad of variants of the three genes that are differentially expressed across populations. Our findings provide insights into potential genetic factors that impact SARS-CoV-2 infectivity in different populations and shed light on the varying expression patterns of FURIN.
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Antibody responses to filovirus infections in humans: protective or not? THE LANCET. INFECTIOUS DISEASES 2021; 21:e348-e355. [PMID: 34175003 DOI: 10.1016/s1473-3099(21)00006-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/29/2020] [Revised: 12/17/2020] [Accepted: 01/04/2021] [Indexed: 12/16/2022]
Abstract
Disease outbreaks caused by Ebola virus and other filoviruses highlight the urgent need for an in-depth understanding of the role of antibody responses in recovery. In this Personal View we aim to discuss the controversial biological role of antibodies during natural filovirus infections in humans. Survival during natural human filovirus infections correlates with the magnitude of the process of antibodies binding to the filovirus glycoprotein and neutralising the virus. Despite the severity of the disease, highly potent monoclonal antibodies have been isolated from survivors of natural filovirus infections, suggesting that the magnitude of the antibody response is insufficient for prevention of severe disease. Unlike natural infections, filovirus vaccines, which express the viral glycoprotein, do induce protective concentrations of antibodies, albeit only when administered at very high doses. Multiple mechanisms by which filoviruses can delay and reduce the antibody response have been identified in the past decade. Furthermore, subneutralising antibody concentrations have been shown to enhance filovirus infections of immune cells bearing Fc receptors. Understanding the role of antibody responses during natural filovirus infections is important for the development of safe and potent vaccines and antibody-based treatments.
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12
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Nemunaitis J, Stanbery L, Senzer N. Severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infection: let the virus be its own demise. Future Virol 2020. [PMCID: PMC7249572 DOI: 10.2217/fvl-2020-0068] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
There has been a collaborative global effort to construct novel therapeutic and prophylactic approaches to SARS-CoV-2 management. Although vaccine development is crucial, acute management of newly infected patients, especially those with severe acute respiratory distress syndrome, is a priority. Herein we describe the rationale and potential of repurposing a dual plasmid, Vigil (pbi-shRNAfurin-GM-CSF), now in Phase III cancer trials, for the treatment of and, in certain circumstances, enhancement of the immune response to SARS-CoV-2.
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13
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Ilinykh PA, Huang K, Santos RI, Gilchuk P, Gunn BM, Karim MM, Liang J, Fouch ME, Davidson E, Parekh DV, Kimble JB, Pietzsch CA, Meyer M, Kuzmina NA, Zeitlin L, Saphire EO, Alter G, Crowe JE, Bukreyev A. Non-neutralizing Antibodies from a Marburg Infection Survivor Mediate Protection by Fc-Effector Functions and by Enhancing Efficacy of Other Antibodies. Cell Host Microbe 2020; 27:976-991.e11. [PMID: 32320678 DOI: 10.1016/j.chom.2020.03.025] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2019] [Revised: 12/10/2019] [Accepted: 03/26/2020] [Indexed: 11/15/2022]
Abstract
Marburg virus (MARV) and Ebola virus (EBOV) belong to the family Filoviridae. MARV causes severe disease in humans with high fatality. We previously isolated a large panel of monoclonal antibodies (mAbs) from B cells of a human survivor with previous naturally acquired MARV infection. Here, we characterized functional properties of these mAbs and identified non-neutralizing mAbs targeting the glycoprotein (GP) 2 portion of the mucin-like domain (MLD) of MARV GP, termed the wing region. One mAb targeting the GP2 wing, MR228, showed therapeutic protection in mice and guinea pigs infected with MARV. The protection was mediated by the Fc fragment functions of MR228. Binding of another GP2 wing-specific non-neutralizing mAb, MR235, to MARV GP increased accessibility of epitopes in the receptor-binding site (RBS) for neutralizing mAbs, resulting in enhanced virus neutralization by these mAbs. These findings highlight an important role for non-neutralizing mAbs during natural human MARV infection.
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Affiliation(s)
- Philipp A Ilinykh
- Department of Pathology, University of Texas Medical Branch, Galveston, TX, USA; Galveston National Laboratory, Galveston, TX, USA
| | - Kai Huang
- Department of Pathology, University of Texas Medical Branch, Galveston, TX, USA; Galveston National Laboratory, Galveston, TX, USA
| | - Rodrigo I Santos
- Department of Pathology, University of Texas Medical Branch, Galveston, TX, USA; Galveston National Laboratory, Galveston, TX, USA
| | - Pavlo Gilchuk
- Vanderbilt Vaccine Center, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Bronwyn M Gunn
- Ragon Institute of MGH, MIT, and Harvard, Cambridge, MA, USA
| | - Marcus M Karim
- Ragon Institute of MGH, MIT, and Harvard, Cambridge, MA, USA
| | - Jenny Liang
- Integral Molecular, Philadelphia, PA 19104, USA
| | | | | | - Diptiben V Parekh
- Department of Immunology and Microbiology, The Scripps Research Institute, La Jolla, CA, USA
| | - James B Kimble
- Department of Pathology, University of Texas Medical Branch, Galveston, TX, USA; Galveston National Laboratory, Galveston, TX, USA
| | - Colette A Pietzsch
- Department of Pathology, University of Texas Medical Branch, Galveston, TX, USA; Galveston National Laboratory, Galveston, TX, USA
| | - Michelle Meyer
- Department of Pathology, University of Texas Medical Branch, Galveston, TX, USA; Galveston National Laboratory, Galveston, TX, USA
| | - Natalia A Kuzmina
- Department of Pathology, University of Texas Medical Branch, Galveston, TX, USA; Galveston National Laboratory, Galveston, TX, USA
| | | | - Erica Ollmann Saphire
- Department of Immunology and Microbiology, The Scripps Research Institute, La Jolla, CA, USA; Skaggs Institute for Chemical Biology, The Scripps Research Institute, La Jolla, CA, USA
| | - Galit Alter
- Ragon Institute of MGH, MIT, and Harvard, Cambridge, MA, USA
| | - James E Crowe
- Vanderbilt Vaccine Center, Vanderbilt University Medical Center, Nashville, TN, USA; Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, TN, USA; Department of Pediatrics (Infectious Diseases), Vanderbilt University Medical Center, Nashville, TN, USA.
| | - Alexander Bukreyev
- Department of Pathology, University of Texas Medical Branch, Galveston, TX, USA; Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, TX; Galveston National Laboratory, Galveston, TX, USA.
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14
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Izaguirre G. The Proteolytic Regulation of Virus Cell Entry by Furin and Other Proprotein Convertases. Viruses 2019; 11:v11090837. [PMID: 31505793 PMCID: PMC6784293 DOI: 10.3390/v11090837] [Citation(s) in RCA: 101] [Impact Index Per Article: 20.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2019] [Revised: 09/03/2019] [Accepted: 09/06/2019] [Indexed: 12/11/2022] Open
Abstract
A wide variety of viruses exploit furin and other proprotein convertases (PCs) of the constitutive protein secretion pathway in order to regulate their cell entry mechanism and infectivity. Surface proteins of enveloped, as well as non-enveloped, viruses become processed by these proteases intracellularly during morphogenesis or extracellularly after egress and during entry in order to produce mature virions activated for infection. Although viruses also take advantage of other proteases, it is when some viruses become reactive with PCs that they may develop high pathogenicity. Besides reacting with furin, some viruses may also react with the PCs of the other specificity group constituted by PC4/PC5/PACE4/PC7. The targeting of PCs for inhibition may result in a useful strategy to treat infections with some highly pathogenic viruses. A wide variety of PC inhibitors have been developed and tested for their antiviral activity in cell-based assays.
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Affiliation(s)
- Gonzalo Izaguirre
- College of Dentistry, University of Illinois at Chicago, Chicago, IL 60612, USA.
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15
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Braun E, Sauter D. Furin-mediated protein processing in infectious diseases and cancer. Clin Transl Immunology 2019; 8:e1073. [PMID: 31406574 PMCID: PMC6682551 DOI: 10.1002/cti2.1073] [Citation(s) in RCA: 188] [Impact Index Per Article: 37.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2019] [Revised: 07/10/2019] [Accepted: 07/13/2019] [Indexed: 12/17/2022] Open
Abstract
Proteolytic cleavage regulates numerous processes in health and disease. One key player is the ubiquitously expressed serine protease furin, which cleaves a plethora of proteins at polybasic recognition motifs. Mammalian substrates of furin include cytokines, hormones, growth factors and receptors. Thus, it is not surprising that aberrant furin activity is associated with a variety of disorders including cancer. Furthermore, the enzymatic activity of furin is exploited by numerous viral and bacterial pathogens, thereby enhancing their virulence and spread. In this review, we describe the physiological and pathophysiological substrates of furin and discuss how dysregulation of a simple proteolytic cleavage event may promote infectious diseases and cancer. One major focus is the role of furin in viral glycoprotein maturation and pathogenicity. We also outline cellular mechanisms regulating the expression and activation of furin and summarise current approaches that target this protease for therapeutic intervention.
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Affiliation(s)
- Elisabeth Braun
- Institute of Molecular VirologyUlm University Medical CenterUlmGermany
| | - Daniel Sauter
- Institute of Molecular VirologyUlm University Medical CenterUlmGermany
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16
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Braun E, Hotter D, Koepke L, Zech F, Groß R, Sparrer KM, Müller JA, Pfaller CK, Heusinger E, Wombacher R, Sutter K, Dittmer U, Winkler M, Simmons G, Jakobsen MR, Conzelmann KK, Pöhlmann S, Münch J, Fackler OT, Kirchhoff F, Sauter D. Guanylate-Binding Proteins 2 and 5 Exert Broad Antiviral Activity by Inhibiting Furin-Mediated Processing of Viral Envelope Proteins. Cell Rep 2019; 27:2092-2104.e10. [DOI: 10.1016/j.celrep.2019.04.063] [Citation(s) in RCA: 73] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2018] [Revised: 03/11/2019] [Accepted: 04/12/2019] [Indexed: 12/13/2022] Open
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17
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Keshwara R, Hagen KR, Abreu-Mota T, Papaneri AB, Liu D, Wirblich C, Johnson RF, Schnell MJ. A Recombinant Rabies Virus Expressing the Marburg Virus Glycoprotein Is Dependent upon Antibody-Mediated Cellular Cytotoxicity for Protection against Marburg Virus Disease in a Murine Model. J Virol 2019; 93:e01865-18. [PMID: 30567978 PMCID: PMC6401435 DOI: 10.1128/jvi.01865-18] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2018] [Accepted: 12/10/2018] [Indexed: 12/14/2022] Open
Abstract
Marburg virus (MARV) is a filovirus related to Ebola virus (EBOV) associated with human hemorrhagic disease. Outbreaks are sporadic and severe, with a reported case mortality rate of upward of 88%. There is currently no antiviral or vaccine available. Given the sporadic nature of outbreaks, vaccines provide the best approach for long-term control of MARV in regions of endemicity. We have developed an inactivated rabies virus-vectored MARV vaccine (FILORAB3) to protect against Marburg virus disease. Immunogenicity studies in our labs have shown that a Th1-biased seroconversion to both rabies virus and MARV glycoproteins (GPs) is beneficial for protection in a preclinical murine model. As such, we adjuvanted FILORAB3 with glucopyranosyl lipid adjuvant (GLA), a Toll-like receptor 4 agonist, in a squalene-in-water emulsion. Across two different BALB/c mouse challenge models, we achieved 92% protection against murine-adapted Marburg virus (ma-MARV). Although our vaccine elicited strong MARV GP antibodies, it did not strongly induce neutralizing antibodies. Through both in vitro and in vivo approaches, we elucidated a critical role for NK cell-dependent antibody-mediated cellular cytotoxicity (ADCC) in vaccine-induced protection. Overall, these findings demonstrate that FILORAB3 is a promising vaccine candidate for Marburg virus disease.IMPORTANCE Marburg virus (MARV) is a virus similar to Ebola virus and also causes a hemorrhagic disease which is highly lethal. In contrast to EBOV, only a few vaccines have been developed against MARV, and researchers do not understand what kind of immune responses are required to protect from MARV. Here we show that antibodies directed against MARV after application of our vaccine protect in an animal system but fail to neutralize the virus in a widely used virus neutralization assay against MARV. This newly discovered activity needs to be considered more when analyzing MARV vaccines or infections.
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Affiliation(s)
- Rohan Keshwara
- Department of Microbiology and Immunology, Sidney Kimmel Medical College at Thomas Jefferson University, Philadelphia, Pennsylvania, USA
| | - Katie R Hagen
- Integrated Research Facility, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Fort Detrick, Maryland, USA
| | - Tiago Abreu-Mota
- Department of Microbiology and Immunology, Sidney Kimmel Medical College at Thomas Jefferson University, Philadelphia, Pennsylvania, USA
- Life and Health Sciences Research Institute (ICVS) School of Medicine, University of Minho, Braga, Portugal
- ICVS/3B's, PT Government Associate Laboratory, Braga/Guimarães, Portugal
| | - Amy B Papaneri
- Emerging Viral Pathogens Section, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, USA
| | - David Liu
- Integrated Research Facility, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Fort Detrick, Maryland, USA
| | - Christoph Wirblich
- Department of Microbiology and Immunology, Sidney Kimmel Medical College at Thomas Jefferson University, Philadelphia, Pennsylvania, USA
| | - Reed F Johnson
- Emerging Viral Pathogens Section, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, USA
| | - Matthias J Schnell
- Department of Microbiology and Immunology, Sidney Kimmel Medical College at Thomas Jefferson University, Philadelphia, Pennsylvania, USA
- Jefferson Vaccine Center, Sidney Kimmel Medical College at Thomas Jefferson University, Philadelphia, Pennsylvania, USA
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18
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Babirye P, Musubika C, Kirimunda S, Downing R, Lutwama JJ, Mbidde EK, Weyer J, Paweska JT, Joloba ML, Wayengera M. Identity and validity of conserved B cell epitopes of filovirus glycoprotein: towards rapid diagnostic testing for Ebola and possibly Marburg virus disease. BMC Infect Dis 2018; 18:498. [PMID: 30285648 PMCID: PMC6171133 DOI: 10.1186/s12879-018-3409-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2018] [Accepted: 09/23/2018] [Indexed: 11/13/2022] Open
Abstract
Background Ebolavirus and Marburgvirus are genera of the virus family Filoviridae. Filoviruses cause rare but fatal viral hemorrhagic fevers (VHFs) in remote villages of equatorial Africa with potential for regional and international spread. Point-of-care (POC) rapid diagnostic tests (RDTs) are critical for early epidemic detection, reponse and control. There are 2 RDTs for Zaire ebolavirus (EBOV), but not other Ebolavirus spp. or Marburg marburgvirus (MARV). We validate 3 conserved B cell epitopes of filovirus glycoprotein (GP) using ebola virus diseases (EVD) survivor samples, towards devising pan-filovirus RDTs. Methods In-silico Immuno-informatics:- (a) multiple and basic local alignments of amino-acid sequences of filovirus (4 Ebolavirus spp. & MARV) Gp1, 2 and epitope prediction and conservation analyses within context of ClusterW, BLAST-P and the immune epitope database analysis resource (IEDB-AR); alongside (b) in-vitro enzyme immuno-assays (EIAs) for SUDV Gp1, 2 antigen and host-specific antibodies (IgM and IgG) among 94 gamma irradiated EVD survivor serum and 9 negative controls. Results Linear B cell epitopes were present across the entire length of all Gp1, 2, most lying in the region between amino acids positioned 350 and 500. Three seperate epitopes 97/80_GAFFLYDRLAST, 39_YEAGEWAENCY and 500_CGLRQLANETTQALQLFLRATTELR (designated UG-Filo-Peptide− 1, 2 and 3 respectively) were conserved within all studied filovirus species Gp1, 2. Gp1, 2 host specific IgM levels were comparably low (av. ODs < 0.04 [95% CI: 0.02837 to 0.04033]) among the 9 negative controls and 57 survivor samples analyzed. Host specific IgG levels, on the other hand, were elevated (av. ODs > 1.7525 [95% CI: 0.3010 to 3.1352]) among the 92 survivor samples relative to the 9 negative controls (av. ODs < 0.2.321 [95% CI: -0.7596 to 0.5372]). Filovirus Gp1, 2 antigen was not detected [av. ODs < 0.20] within EVD survivor serum relative to recombinant protein positive controls [av. ODs = 0.50]. Conclusions These conserved B cell epitopes of filovirus Gp1, 2 and their derivative antibodies are promising for research and development of RDTs for EVD, with potential for extension to detect MVD. Electronic supplementary material The online version of this article (10.1186/s12879-018-3409-x) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Peace Babirye
- Department of Immunology and Molecular Biology, School of Biomedical Sciences, College of Health Sciences, Makerere University, P o Box 7072, Kampala, Uganda
| | - Carol Musubika
- Department of Immunology and Molecular Biology, School of Biomedical Sciences, College of Health Sciences, Makerere University, P o Box 7072, Kampala, Uganda
| | - Samuel Kirimunda
- Department of Immunology and Molecular Biology, School of Biomedical Sciences, College of Health Sciences, Makerere University, P o Box 7072, Kampala, Uganda
| | - Robert Downing
- Arbovirology and Filovirology Laboratories/Centers for Disease Control-CDC, Uganda Virus Research Institute (UVRI), Entebbe, Uganda
| | - Julian J Lutwama
- Arbovirology and Filovirology Laboratories/Centers for Disease Control-CDC, Uganda Virus Research Institute (UVRI), Entebbe, Uganda
| | - Edward K Mbidde
- Arbovirology and Filovirology Laboratories/Centers for Disease Control-CDC, Uganda Virus Research Institute (UVRI), Entebbe, Uganda
| | - Jacqueline Weyer
- Center for Emerging Zoonotic Diseases, National Institute for Communicable Diseases, Johanesburg, South Africa
| | - Janusz T Paweska
- Center for Emerging Zoonotic Diseases, National Institute for Communicable Diseases, Johanesburg, South Africa
| | - Moses L Joloba
- Department of Immunology and Molecular Biology, School of Biomedical Sciences, College of Health Sciences, Makerere University, P o Box 7072, Kampala, Uganda
| | - Misaki Wayengera
- Department of Immunology and Molecular Biology, School of Biomedical Sciences, College of Health Sciences, Makerere University, P o Box 7072, Kampala, Uganda. .,Unit of Genetics & Genomics & Department of Pathology, School of Biomedical Sciences, College of Health Sciences, Makerere University, P o Box 7072, Kampala, Uganda.
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19
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Mittler E, Schudt G, Halwe S, Rohde C, Becker S. A Fluorescently Labeled Marburg Virus Glycoprotein as a New Tool to Study Viral Transport and Assembly. J Infect Dis 2018; 218:S318-S326. [DOI: 10.1093/infdis/jiy424] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Eva Mittler
- Institut für Virologie, Philipps-Universität Marburg, Marburg, Germany
| | - Gordian Schudt
- Institut für Virologie, Philipps-Universität Marburg, Marburg, Germany
| | - Sandro Halwe
- Institut für Virologie, Philipps-Universität Marburg, Marburg, Germany
- German Center of Infection Research, Partner Site Giessen-Marburg-Langen, Marburg, Germany
| | - Cornelius Rohde
- Institut für Virologie, Philipps-Universität Marburg, Marburg, Germany
- German Center of Infection Research, Partner Site Giessen-Marburg-Langen, Marburg, Germany
| | - Stephan Becker
- Institut für Virologie, Philipps-Universität Marburg, Marburg, Germany
- German Center of Infection Research, Partner Site Giessen-Marburg-Langen, Marburg, Germany
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20
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The structural basis for filovirus neutralization by monoclonal antibodies. Curr Opin Immunol 2018; 53:196-202. [PMID: 29940415 DOI: 10.1016/j.coi.2018.05.001] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2018] [Revised: 04/30/2018] [Accepted: 05/02/2018] [Indexed: 12/21/2022]
Abstract
Filoviruses, including ebolaviruses and marburgviruses, are the causative agents of highly lethal disease outbreaks. The 2013-2016 Ebola virus outbreak was responsible for >28000 infections and >11000 deaths. Although there are currently no licensed vaccines or therapeutics for any filovirus-induced disease, monoclonal antibodies (mAbs) are among the most promising options for therapeutic development. Hundreds of mAbs have been isolated from human survivors of filovirus infections that target the viral spike glycoprotein (GP). The binding, neutralization, and cross-reactivity of many of these mAbs has been determined. Several mAbs have been characterized structurally, and this information has been crucial for strategizing therapeutic and vaccine design. Here we present an overview of the structural features of the neutralizing/protective epitopes on filovirus glycoproteins.
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21
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Böttcher-Friebertshäuser E, Garten W, Klenk HD. Characterization of Proprotein Convertases and Their Involvement in Virus Propagation. ACTIVATION OF VIRUSES BY HOST PROTEASES 2018. [PMCID: PMC7122180 DOI: 10.1007/978-3-319-75474-1_9] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Affiliation(s)
| | - Wolfgang Garten
- Institut für Virologie, Philipps Universität, Marburg, Germany
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22
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Filovirus proteins for antiviral drug discovery: Structure/function of proteins involved in assembly and budding. Antiviral Res 2018; 150:183-192. [DOI: 10.1016/j.antiviral.2017.12.022] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2017] [Revised: 12/20/2017] [Accepted: 12/28/2017] [Indexed: 01/30/2023]
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23
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King LB, Fusco ML, Flyak AI, Ilinykh PA, Huang K, Gunn B, Kirchdoerfer RN, Hastie KM, Sangha AK, Meiler J, Alter G, Bukreyev A, Crowe JE, Saphire EO. The Marburgvirus-Neutralizing Human Monoclonal Antibody MR191 Targets a Conserved Site to Block Virus Receptor Binding. Cell Host Microbe 2018; 23:101-109.e4. [PMID: 29324225 PMCID: PMC5772738 DOI: 10.1016/j.chom.2017.12.003] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2017] [Revised: 10/28/2017] [Accepted: 12/08/2017] [Indexed: 11/22/2022]
Abstract
Since their first identification 50 years ago, marburgviruses have emerged several times, with 83%-90% lethality in the largest outbreaks. Although no vaccines or therapeutics are available for human use, the human antibody MR191 provides complete protection in non-human primates when delivered several days after inoculation of a lethal marburgvirus dose. The detailed neutralization mechanism of MR191 remains outstanding. Here we present a 3.2 Å crystal structure of MR191 complexed with a trimeric marburgvirus surface glycoprotein (GP). MR191 neutralizes by occupying the conserved receptor-binding site and competing with the host receptor Niemann-Pick C1. The structure illuminates previously disordered regions of GP including the stalk, fusion loop, CX6CC switch, and an N-terminal region of GP2 that wraps about the outside of GP1 to anchor a marburgvirus-specific "wing" antibody epitope. Virus escape mutations mapped far outside the MR191 receptor-binding site footprint suggest a role for these other regions in the GP quaternary structure.
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Affiliation(s)
- Liam B King
- Department of Immunology and Microbiology, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Marnie L Fusco
- Department of Immunology and Microbiology, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Andrew I Flyak
- Departments of Pediatrics, Pathology, Microbiology, and Immunology, and the Vanderbilt Vaccine Center, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Philipp A Ilinykh
- Department of Pathology, University of Texas Medical Branch, Galveston, TX 77555, USA; Galveston National Laboratory, Galveston, TX 77550, USA
| | - Kai Huang
- Department of Pathology, University of Texas Medical Branch, Galveston, TX 77555, USA; Galveston National Laboratory, Galveston, TX 77550, USA
| | - Bronwyn Gunn
- Ragon Institute of Massachusetts General Hospital, Massachusetts Institute of Technology and Harvard University, Cambridge, MA 02139, USA
| | - Robert N Kirchdoerfer
- Department of Immunology and Microbiology, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Kathryn M Hastie
- Department of Immunology and Microbiology, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Amandeep K Sangha
- Department of Chemistry and Center for Structural Biology, Vanderbilt University, Nashville, TN 37232, USA
| | - Jens Meiler
- Department of Chemistry and Center for Structural Biology, Vanderbilt University, Nashville, TN 37232, USA
| | - Galit Alter
- Ragon Institute of Massachusetts General Hospital, Massachusetts Institute of Technology and Harvard University, Cambridge, MA 02139, USA
| | - Alexander Bukreyev
- Department of Pathology, University of Texas Medical Branch, Galveston, TX 77555, USA; Department of Microbiology & Immunology, University of Texas Medical Branch, Galveston, TX 77555, USA; Galveston National Laboratory, Galveston, TX 77550, USA
| | - James E Crowe
- Departments of Pediatrics, Pathology, Microbiology, and Immunology, and the Vanderbilt Vaccine Center, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Erica Ollmann Saphire
- Department of Immunology and Microbiology, The Scripps Research Institute, La Jolla, CA 92037, USA; Skaggs Institute for Chemical Biology, The Scripps Research Institute, La Jolla, CA 92037, USA.
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24
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Proteolytic Processing of Filovirus Glycoproteins. ACTIVATION OF VIRUSES BY HOST PROTEASES 2018. [PMCID: PMC7122482 DOI: 10.1007/978-3-319-75474-1_5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/03/2022]
Abstract
Filoviruses (Marburg virus and Ebola virus) have a single envelope glycoprotein (GP) that initiates infection. GP is a class I fusion protein that forms trimeric spikes composed of heterodimers of the subunits GP1 and GP2. GP1 and GP2 are derived from the precursor pre-GP by furin cleavage during exocytosis. GP1 contains a receptor-binding core topped by a glycan cap and a heavily glycosylated mucin-like domain, while GP2 contains a fusion loop and a membrane anchor. After entering cells by macropinocytosis, the glycan cap and the mucin-like domain are removed from GP1 by endosomal cathepsins B and L exposing the binding site for the Niemann-Pick C1 receptor. It appears that there is no strict requirement for specific proteases involved in GP processing. Thus, furin is not indispensible for GP1-2 cleavage, and GP1 may be trimmed not only by cathepsins B and L but also by other endosomal proteases. Two soluble glycoproteins of Ebola virus are also processed by host proteases. A significant amount of GP1,2 is cleaved by the metalloprotease TACE and shed from the surface of infected cells (GP1,2 delta). The secreted protein sGP is derived from the precursor pre-sGP by furin cleavage.
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25
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Clarke EC, Collar AL, Ye C, Caì Y, Anaya E, Rinaldi D, Martinez B, Yarborough S, Merle C, Theisen M, Wada J, Kuhn JH, Bradfute SB. Production and Purification of Filovirus Glycoproteins in Insect and Mammalian Cell Lines. Sci Rep 2017; 7:15091. [PMID: 29118454 PMCID: PMC5678155 DOI: 10.1038/s41598-017-15416-3] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2017] [Accepted: 10/26/2017] [Indexed: 01/10/2023] Open
Abstract
Filoviruses are highly virulent pathogens capable of causing severe disease. The glycoproteins of filoviruses are the only virally expressed proteins on the virion surface and are required for receptor binding. As such, they are the main candidate vaccine antigen. Despite their virulence, most filoviruses are not comprehensively characterized, and relatively few commercially produced reagents are available for their study. Here, we describe two methods for production and purification of filovirus glycoproteins in insect and mammalian cell lines. Considerations of expression vector choice, modifications to sequence, troubleshooting of purification method, and glycosylation differences are all important for successful expression of filovirus glycoproteins in cell lines. Given the scarcity of commercially available filovirus glycoproteins, we hope our experiences with possible difficulties in purification of the proteins will facilitate other researchers to produce and purify filovirus glycoproteins rapidly.
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Affiliation(s)
- Elizabeth C Clarke
- Center for Global Health, Division of Infectious Diseases, Department of Internal Medicine, University of New Mexico, Albuquerque, New Mexico, 87131, USA
| | - Amanda L Collar
- Center for Global Health, Division of Infectious Diseases, Department of Internal Medicine, University of New Mexico, Albuquerque, New Mexico, 87131, USA
| | - Chunyan Ye
- Center for Global Health, Division of Infectious Diseases, Department of Internal Medicine, University of New Mexico, Albuquerque, New Mexico, 87131, USA
| | - Yíngyún Caì
- Integrated Research Facility at Fort Detrick, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Frederick, Maryland, 21702, USA
| | - Eduardo Anaya
- Department of Pathology, University of New Mexico, Albuquerque, New Mexico, 87131, USA
| | - Derek Rinaldi
- Department of Pathology, University of New Mexico, Albuquerque, New Mexico, 87131, USA
| | - Britney Martinez
- Undergraduate Pipeline Network, University of New Mexico, Albuquerque, New Mexico, 87131, USA
| | - Sarah Yarborough
- Undergraduate Pipeline Network, University of New Mexico, Albuquerque, New Mexico, 87131, USA
| | | | | | - Jiro Wada
- Integrated Research Facility at Fort Detrick, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Frederick, Maryland, 21702, USA
| | - Jens H Kuhn
- Integrated Research Facility at Fort Detrick, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Frederick, Maryland, 21702, USA
| | - Steven B Bradfute
- Center for Global Health, Division of Infectious Diseases, Department of Internal Medicine, University of New Mexico, Albuquerque, New Mexico, 87131, USA.
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Hashiguchi T. [Molecular basis for negative-strand RNA virus entry and neutralization by antibodies]. Uirusu 2017; 67:69-78. [PMID: 29593155 DOI: 10.2222/jsv.67.69] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Mononegaviruses are non-segmented negative-strand RNA viruses, and include measles, mumps, Marburg, and Ebola viruses. Measles virus and mumps virus, members of the family Paramyxoviridae, are immunotropic and neurotropic, respectively. Marburg virus and Ebola virus, members of the family Filoviridae, cause highly lethal hemorrhagic fever. In this paper, I summarize the recent structural and functional studies on the viral glycoproteins (GPs) of these viruses, which have shed light on virus entry and the humoral response. The structural and functional analyses of the interaction between viral GPs and receptors/antibodies also illuminate directions toward therapeutics against the viruses.
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Affiliation(s)
- Takao Hashiguchi
- Affiliation; Department of Virology, Faculty of medicine, Kyushu University
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27
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Filovirus proteins for antiviral drug discovery: A structure/function analysis of surface glycoproteins and virus entry. Antiviral Res 2016; 135:1-14. [PMID: 27640102 PMCID: PMC7113884 DOI: 10.1016/j.antiviral.2016.09.001] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2016] [Revised: 09/01/2016] [Accepted: 09/05/2016] [Indexed: 12/20/2022]
Abstract
This review focuses on the recent progress in our understanding of filovirus protein structure/function and its impact on antiviral research. Here we focus on the surface glycoprotein GP1,2 and its different roles in filovirus entry. We first describe the latest advances on the characterization of GP gene-overlapping proteins sGP, ssGP and Δ-peptide. Then, we compare filovirus surface GP1,2 proteins in terms of structure, synthesis and function. As they bear potential in drug-design, the discovery of small organic compounds inhibiting filovirus entry is a currently very active field. Although it is at an early stage, the development of antiviral drugs against Ebola and Marburg virus entry might prove essential to reduce outbreak-associated fatality rates through post-exposure treatment of both suspected and confirmed cases. The filovirus surface glycoprotein is the key player protein responsible for viral entry. Secreted forms of the glycoprotein have been suggested to participate to filovirus virus pathogenicity. Recent structural insights of the filovirus surface glycoprotein highlight new antiviral perspectives. Interesting compounds and innovative antiviral strategies emerge from research and development to inhibit filovirus entry.
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28
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Banadyga L, Dolan MA, Ebihara H. Rodent-Adapted Filoviruses and the Molecular Basis of Pathogenesis. J Mol Biol 2016; 428:3449-66. [PMID: 27189922 PMCID: PMC5010511 DOI: 10.1016/j.jmb.2016.05.008] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2016] [Revised: 05/04/2016] [Accepted: 05/06/2016] [Indexed: 11/29/2022]
Abstract
Ebola, Marburg, and Ravn viruses, all filoviruses, are the causative agents of severe hemorrhagic fever. Much of what we understand about the pathogenesis of filovirus disease is derived from work with animal models, including nonhuman primates, which are considered the "gold standard" filovirus model since they faithfully recapitulate the clinical hallmarks of filovirus disease. However, rodent models, including the mouse, guinea pig, and hamster, also exist for Ebola, Marburg, and Ravn viruses, and although they may not reproduce all the clinical signs of filovirus disease, thanks to their relative ease of use and low cost, they are often the first choice for initial descriptions of virus pathogenesis and evaluation of antiviral prophylactics and therapeutics. Since filoviruses do not cause significant disease in adult, immunocompetent rodents, these models rely on "rodent-adapted" viruses that have been passaged several times through their host until virulence and lethality are achieved. In the process of adaptation, the viruses acquire numerous nucleotide/amino acid mutations that contribute to virulence in their rodent host. Interestingly, virus protein 24 (VP24) and nucleoprotein (NP) appear to be major virulence factors for ebolaviruses in rodents, whereas VP40 appears to be the major virulence factor for marburgviruses. By characterizing these mutations and understanding the molecular mechanisms that lead to the acquisition of virulence, we can gain better insight into the pathogenic processes that underlie filovirus disease in humans. These processes, and the viral and/or cellular proteins that contribute to them, will make attractive targets for the development of novel therapeutics and counter-measures.
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Affiliation(s)
- Logan Banadyga
- Laboratory of Virology, Division of Intramural Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, MT 59840, USA
| | - Michael A Dolan
- Bioinformatics and Computational Biosciences Branch, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Hideki Ebihara
- Laboratory of Virology, Division of Intramural Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, MT 59840, USA.
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29
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Schmidt KM, Mühlberger E. Marburg Virus Reverse Genetics Systems. Viruses 2016; 8:E178. [PMID: 27338448 PMCID: PMC4926198 DOI: 10.3390/v8060178] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2016] [Revised: 06/14/2016] [Accepted: 06/16/2016] [Indexed: 12/16/2022] Open
Abstract
The highly pathogenic Marburg virus (MARV) is a member of the Filoviridae family and belongs to the group of nonsegmented negative-strand RNA viruses. Reverse genetics systems established for MARV have been used to study various aspects of the viral replication cycle, analyze host responses, image viral infection, and screen for antivirals. This article provides an overview of the currently established MARV reverse genetic systems based on minigenomes, infectious virus-like particles and full-length clones, and the research that has been conducted using these systems.
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Affiliation(s)
- Kristina Maria Schmidt
- Friedrich-Loeffler-Institut, Federal Research Institute for Animal Health, Institute of Novel and Emerging Infectious Diseases, Greifswald-Insel Riems 17493, Germany.
| | - Elke Mühlberger
- Department of Microbiology, School of Medicine, Boston University, 620 Albany Street, Boston, MA 02118, USA.
- National Emerging Infectious Diseases Laboratories (NEIDL), Boston University, 620 Albany Street, Boston, MA 02118, USA.
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30
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Zivcec M, Scholte FEM, Spiropoulou CF, Spengler JR, Bergeron É. Molecular Insights into Crimean-Congo Hemorrhagic Fever Virus. Viruses 2016; 8:106. [PMID: 27110812 PMCID: PMC4848600 DOI: 10.3390/v8040106] [Citation(s) in RCA: 73] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2016] [Revised: 04/15/2016] [Accepted: 04/18/2016] [Indexed: 01/11/2023] Open
Abstract
Crimean-Congo hemorrhagic fever virus (CCHFV) is a tick-borne pathogen that causes high morbidity and mortality. Efficacy of vaccines and antivirals to treat human CCHFV infections remains limited and controversial. Research into pathology and underlying molecular mechanisms of CCHFV and other nairoviruses is limited. Significant progress has been made in our understanding of CCHFV replication and pathogenesis in the past decade. Here we review the most recent molecular advances in CCHFV-related research, and provide perspectives on future research.
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Affiliation(s)
- Marko Zivcec
- Viral Special Pathogens Branch, Division of High Consequence Pathogens and Pathology, Centers for Disease Control and Prevention, Atlanta, GA 30333, USA.
| | - Florine E M Scholte
- Viral Special Pathogens Branch, Division of High Consequence Pathogens and Pathology, Centers for Disease Control and Prevention, Atlanta, GA 30333, USA.
| | - Christina F Spiropoulou
- Viral Special Pathogens Branch, Division of High Consequence Pathogens and Pathology, Centers for Disease Control and Prevention, Atlanta, GA 30333, USA.
| | - Jessica R Spengler
- Viral Special Pathogens Branch, Division of High Consequence Pathogens and Pathology, Centers for Disease Control and Prevention, Atlanta, GA 30333, USA.
| | - Éric Bergeron
- Viral Special Pathogens Branch, Division of High Consequence Pathogens and Pathology, Centers for Disease Control and Prevention, Atlanta, GA 30333, USA.
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31
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Chimeric Filoviruses for Identification and Characterization of Monoclonal Antibodies. J Virol 2016; 90:3890-3901. [PMID: 26819310 DOI: 10.1128/jvi.00101-16] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2016] [Accepted: 01/22/2016] [Indexed: 11/20/2022] Open
Abstract
UNLABELLED Recent experiments suggest that some glycoprotein (GP)-specific monoclonal antibodies (MAbs) can protect experimental animals against the filovirus Ebola virus (EBOV). There is a need for isolation of MAbs capable of neutralizing multiple filoviruses. Antibody neutralization assays for filoviruses frequently use surrogate systems such as the rhabdovirus vesicular stomatitis Indiana virus (VSV), lentiviruses or gammaretroviruses with their envelope proteins replaced with EBOV GP or pseudotyped with EBOV GP. It is optimal for both screening and in-depth characterization of newly identified neutralizing MAbs to generate recombinant filoviruses that express a reporter fluorescent protein in order to more easily monitor and quantify the infection. Our study showed that unlike neutralization-sensitive chimeric VSV, authentic filoviruses are highly resistant to neutralization by MAbs. We used reverse genetics techniques to replace EBOV GP with its counterpart from the heterologous filoviruses Bundibugyo virus (BDBV), Sudan virus, and even Marburg virus and Lloviu virus, which belong to the heterologous genera in the filovirus family. This work resulted in generation of multiple chimeric filoviruses, demonstrating the ability of filoviruses to tolerate swapping of the envelope protein. The sensitivity of chimeric filoviruses to neutralizing MAbs was similar to that of authentic biologically derived filoviruses with the same GP. Moreover, disabling the expression of the secreted GP (sGP) resulted in an increased susceptibility of an engineered virus to the BDBV52 MAb isolated from a BDBV survivor, suggesting a role for sGP in evasion of antibody neutralization in the context of a human filovirus infection. IMPORTANCE The study demonstrated that chimeric rhabdoviruses in which G protein is replaced with filovirus GP, widely used as surrogate targets for characterization of filovirus neutralizing antibodies, do not accurately predict the ability of antibodies to neutralize authentic filoviruses, which appeared to be resistant to neutralization. However, a recombinant EBOV expressing a fluorescent protein tolerated swapping of GP with counterparts from heterologous filoviruses, allowing high-throughput screening of B cell lines to isolate MAbs of any filovirus specificity. Human MAb BDBV52, which was isolated from a survivor of BDBV infection, was capable of partially neutralizing a chimeric EBOV carrying BDBV GP in which expression of sGP was disabled. In contrast, the parental virus expressing sGP was resistant to the MAb. Thus, the ability of filoviruses to tolerate swapping of GP can be used for identification of neutralizing MAbs specific to any filovirus and for the characterization of MAb specificity and mechanism of action.
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32
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Protective mAbs and Cross-Reactive mAbs Raised by Immunization with Engineered Marburg Virus GPs. PLoS Pathog 2015; 11:e1005016. [PMID: 26115029 PMCID: PMC4482612 DOI: 10.1371/journal.ppat.1005016] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2015] [Accepted: 06/09/2015] [Indexed: 11/25/2022] Open
Abstract
The filoviruses, which include the marburg- and ebolaviruses, have caused multiple outbreaks among humans this decade. Antibodies against the filovirus surface glycoprotein (GP) have been shown to provide life-saving therapy in nonhuman primates, but such antibodies are generally virus-specific. Many monoclonal antibodies (mAbs) have been described against Ebola virus. In contrast, relatively few have been described against Marburg virus. Here we present ten mAbs elicited by immunization of mice using recombinant mucin-deleted GPs from different Marburg virus (MARV) strains. Surprisingly, two of the mAbs raised against MARV GP also cross-react with the mucin-deleted GP cores of all tested ebolaviruses (Ebola, Sudan, Bundibugyo, Reston), but these epitopes are masked differently by the mucin-like domains themselves. The most efficacious mAbs in this panel were found to recognize a novel “wing” feature on the GP2 subunit that is unique to Marburg and does not exist in Ebola. Two of these anti-wing antibodies confer 90 and 100% protection, respectively, one hour post-exposure in mice challenged with MARV. The filoviruses have caused multiple outbreaks among humans this decade, including a 90% lethal outbreak of Marburg virus in Angola and a significant, sustained outbreak of Ebola virus in West Africa. The viral surface glycoprotein (GP), which enables filoviruses to infect host cells, is the primary target of the immune system. Antibodies that target filovirus GP have been shown to provide life-saving therapy in nonhuman primates. However, the majority of known antibodies are only reactive against Ebola virus and not other emerging filoviruses. In this study, we present ten antibodies against Marburg virus, elicited by immunization of mice using engineered forms of its GP. Surprisingly, two antibodies exhibit some cross-reactivity to ebolaviruses (including species Ebola, Sudan, Bundibugyo, Reston). Other antibodies in this panel recognize a novel “wing” feature on a portion of GP that is unique to Marburg and does not exist in ebolaviruses, and protect 90%-100% of mice from lethal exposure. These antibodies, and their structural and functional analysis presented here, illuminate directions forward for therapeutics against Marburg virus.
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33
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Clinton TR, Weinstock MT, Jacobsen MT, Szabo-Fresnais N, Pandya MJ, Whitby FG, Herbert AS, Prugar LI, McKinnon R, Hill CP, Welch BD, Dye JM, Eckert DM, Kay MS. Design and characterization of ebolavirus GP prehairpin intermediate mimics as drug targets. Protein Sci 2015; 24:446-63. [PMID: 25287718 PMCID: PMC4380977 DOI: 10.1002/pro.2578] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2014] [Accepted: 10/01/2014] [Indexed: 01/07/2023]
Abstract
Ebolaviruses are highly lethal filoviruses that cause hemorrhagic fever in humans and nonhuman primates. With no approved treatments or preventatives, the development of an anti-ebolavirus therapy to protect against natural infections and potential weaponization is an urgent global health need. Here, we describe the design, biophysical characterization, and validation of peptide mimics of the ebolavirus N-trimer, a highly conserved region of the GP2 fusion protein, to be used as targets to develop broad-spectrum inhibitors of ebolavirus entry. The N-trimer region of GP2 is 90% identical across all ebolavirus species and forms a critical part of the prehairpin intermediate that is exposed during viral entry. Specifically, we fused designed coiled coils to the N-trimer to present it as a soluble trimeric coiled coil as it appears during membrane fusion. Circular dichroism, sedimentation equilibrium, and X-ray crystallography analyses reveal the helical, trimeric structure of the designed N-trimer mimic targets. Surface plasmon resonance studies validate that the N-trimer mimic binds its native ligand, the C-peptide region of GP2. The longest N-trimer mimic also inhibits virus entry, thereby confirming binding of the C-peptide region during viral entry and the presence of a vulnerable prehairpin intermediate. Using phage display as a model system, we validate the suitability of the N-trimer mimics as drug screening targets. Finally, we describe the foundational work to use the N-trimer mimics as targets in mirror-image phage display, which will be used to identify D-peptide inhibitors of ebolavirus entry.
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Affiliation(s)
- Tracy R Clinton
- Department of Biochemistry, University of Utah School of MedicineSalt Lake City, Utah, 84112-5650
| | - Matthew T Weinstock
- Department of Biochemistry, University of Utah School of MedicineSalt Lake City, Utah, 84112-5650
| | - Michael T Jacobsen
- Department of Biochemistry, University of Utah School of MedicineSalt Lake City, Utah, 84112-5650
| | - Nicolas Szabo-Fresnais
- Department of Biochemistry, University of Utah School of MedicineSalt Lake City, Utah, 84112-5650,Cardiology Section, Department of Internal Medicine, University of Utah School of MedicineSalt Lake City, Utah, 84148
| | - Maya J Pandya
- Department of Biochemistry, University of Utah School of MedicineSalt Lake City, Utah, 84112-5650
| | - Frank G Whitby
- Department of Biochemistry, University of Utah School of MedicineSalt Lake City, Utah, 84112-5650
| | - Andrew S Herbert
- U.S. Army Medical Research Institute of Infectious Diseases, Fort DetrickFrederick, Maryland, 21702-5011
| | - Laura I Prugar
- U.S. Army Medical Research Institute of Infectious Diseases, Fort DetrickFrederick, Maryland, 21702-5011
| | - Rena McKinnon
- D-Peptide Research Division, Navigen, Inc.Salt Lake City, Utah, 84108
| | - Christopher P Hill
- Department of Biochemistry, University of Utah School of MedicineSalt Lake City, Utah, 84112-5650
| | - Brett D Welch
- D-Peptide Research Division, Navigen, Inc.Salt Lake City, Utah, 84108
| | - John M Dye
- U.S. Army Medical Research Institute of Infectious Diseases, Fort DetrickFrederick, Maryland, 21702-5011
| | - Debra M Eckert
- Department of Biochemistry, University of Utah School of MedicineSalt Lake City, Utah, 84112-5650,*Correspondence to: Debra M. Eckert; Department of Biochemistry, University of Utah School of Medicine, 15 N. Medical Drive East, Rm 4100, Salt Lake City, UT 84112. E-mail: or Michael S. Kay; Department of Biochemistry, University of Utah School of Medicine, 15 N. Medical Drive East, Rm 4100, Salt Lake City, UT 84112. E-mail:
| | - Michael S Kay
- Department of Biochemistry, University of Utah School of MedicineSalt Lake City, Utah, 84112-5650,*Correspondence to: Debra M. Eckert; Department of Biochemistry, University of Utah School of Medicine, 15 N. Medical Drive East, Rm 4100, Salt Lake City, UT 84112. E-mail: or Michael S. Kay; Department of Biochemistry, University of Utah School of Medicine, 15 N. Medical Drive East, Rm 4100, Salt Lake City, UT 84112. E-mail:
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Kajihara M, Takada A. Host Cell Factors Involved in Filovirus Infection. CURRENT TROPICAL MEDICINE REPORTS 2015. [DOI: 10.1007/s40475-015-0039-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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35
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Ng M, Ndungo E, Jangra RK, Cai Y, Postnikova E, Radoshitzky SR, Dye JM, Ramírez de Arellano E, Negredo A, Palacios G, Kuhn JH, Chandran K. Cell entry by a novel European filovirus requires host endosomal cysteine proteases and Niemann-Pick C1. Virology 2014; 468-470:637-646. [PMID: 25310500 DOI: 10.1016/j.virol.2014.08.019] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2014] [Revised: 07/30/2014] [Accepted: 08/20/2014] [Indexed: 11/19/2022]
Abstract
Lloviu virus (LLOV), a phylogenetically divergent filovirus, is the proposed etiologic agent of die-offs of Schreibers's long-fingered bats (Miniopterus schreibersii) in western Europe. Studies of LLOV remain limited because the infectious agent has not yet been isolated. Here, we generated a recombinant vesicular stomatitis virus expressing the LLOV spike glycoprotein (GP) and used it to show that LLOV GP resembles other filovirus GP proteins in structure and function. LLOV GP must be cleaved by endosomal cysteine proteases during entry, but is much more protease-sensitive than EBOV GP. The EBOV/MARV receptor, Niemann-Pick C1 (NPC1), is also required for LLOV entry, and its second luminal domain is recognized with high affinity by a cleaved form of LLOV GP, suggesting that receptor binding would not impose a barrier to LLOV infection of humans and non-human primates. The use of NPC1 as an intracellular entry receptor may be a universal property of filoviruses.
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Affiliation(s)
- Melinda Ng
- Department of Microbiology and Immunology, Albert Einstein College of Medicine, Bronx, NY 10461, United States
| | - Esther Ndungo
- Department of Microbiology and Immunology, Albert Einstein College of Medicine, Bronx, NY 10461, United States
| | - Rohit K Jangra
- Department of Microbiology and Immunology, Albert Einstein College of Medicine, Bronx, NY 10461, United States
| | - Yingyun Cai
- Integrated Research Facility at Fort Detrick, National Institute for Allergy and Infectious Diseases, National Institutes of Health, Frederick, MD 21702, United States
| | - Elena Postnikova
- Integrated Research Facility at Fort Detrick, National Institute for Allergy and Infectious Diseases, National Institutes of Health, Frederick, MD 21702, United States
| | - Sheli R Radoshitzky
- United States Army Medical Research Institute of Infectious Diseases, Fort Detrick, Frederick, MD 21702, United States
| | - John M Dye
- United States Army Medical Research Institute of Infectious Diseases, Fort Detrick, Frederick, MD 21702, United States
| | | | - Ana Negredo
- National Center of Microbiology, Instituto de Salud Carlos III, 28220 Madrid, Spain
| | - Gustavo Palacios
- United States Army Medical Research Institute of Infectious Diseases, Fort Detrick, Frederick, MD 21702, United States
| | - Jens H Kuhn
- Integrated Research Facility at Fort Detrick, National Institute for Allergy and Infectious Diseases, National Institutes of Health, Frederick, MD 21702, United States
| | - Kartik Chandran
- Department of Microbiology and Immunology, Albert Einstein College of Medicine, Bronx, NY 10461, United States.
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36
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Gnirß K, Fiedler M, Krämer-Kühl A, Bolduan S, Mittler E, Becker S, Schindler M, Pöhlmann S. Analysis of determinants in filovirus glycoproteins required for tetherin antagonism. Viruses 2014; 6:1654-71. [PMID: 24721789 PMCID: PMC4014715 DOI: 10.3390/v6041654] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2013] [Revised: 03/27/2014] [Accepted: 03/30/2014] [Indexed: 01/06/2023] Open
Abstract
The host cell protein tetherin can restrict the release of enveloped viruses from infected cells. The HIV-1 protein Vpu counteracts tetherin by removing it from the site of viral budding, the plasma membrane, and this process depends on specific interactions between the transmembrane domains of Vpu and tetherin. In contrast, the glycoproteins (GPs) of two filoviruses, Ebola and Marburg virus, antagonize tetherin without reducing surface expression, and the domains in GP required for tetherin counteraction are unknown. Here, we show that filovirus GPs depend on the presence of their authentic transmembrane domains for virus-cell fusion and tetherin antagonism. However, conserved residues within the transmembrane domain were dispensable for membrane fusion and tetherin counteraction. Moreover, the insertion of the transmembrane domain into a heterologous viral GP, Lassa virus GPC, was not sufficient to confer tetherin antagonism to the recipient. Finally, mutation of conserved residues within the fusion peptide of Ebola virus GP inhibited virus-cell fusion but did not ablate tetherin counteraction, indicating that the fusion peptide and the ability of GP to drive host cell entry are not required for tetherin counteraction. These results suggest that the transmembrane domains of filoviral GPs contribute to tetherin antagonism but are not the sole determinants.
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Affiliation(s)
- Kerstin Gnirß
- Infection Biology Unit, German Primate Center, 37077 Göttingen, Germany.
| | - Marie Fiedler
- Infection Biology Unit, German Primate Center, 37077 Göttingen, Germany.
| | - Annika Krämer-Kühl
- Infection Biology Unit, German Primate Center, 37077 Göttingen, Germany.
| | - Sebastian Bolduan
- Institute of Virology, Helmholtz Center Munich, 85764 Neuherberg, Germany.
| | - Eva Mittler
- Institute of Virology, Philipps-University-Marburg, 35043 Marburg, Germany.
| | - Stephan Becker
- Institute of Virology, Philipps-University-Marburg, 35043 Marburg, Germany.
| | - Michael Schindler
- Institute of Virology, Helmholtz Center Munich, 85764 Neuherberg, Germany.
| | - Stefan Pöhlmann
- Infection Biology Unit, German Primate Center, 37077 Göttingen, Germany.
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37
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Page A, Volchkova V, Reid S, Mateo M, Bagnaud-Baule A, Nemirov K, Shurtleff A, Lawrence P, Reynard O, Ottmann M, Lotteau V, Biswal S, Thimmulappa R, Bavari S, Volchkov V. Marburgvirus Hijacks Nrf2-Dependent Pathway by Targeting Nrf2-Negative Regulator Keap1. Cell Rep 2014; 6:1026-1036. [DOI: 10.1016/j.celrep.2014.02.027] [Citation(s) in RCA: 63] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2013] [Revised: 12/13/2013] [Accepted: 02/18/2014] [Indexed: 12/26/2022] Open
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38
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Warfield KL, Swenson DL, Demmin G, Bavari S. Filovirus-like particles as vaccines and discovery tools. Expert Rev Vaccines 2014; 4:429-40. [PMID: 16026254 DOI: 10.1586/14760584.4.3.429] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Ebola and Marburg viruses are members of the family Filoviridae, which cause severe hemorrhagic fevers in humans. Filovirus outbreaks have been sporadic, with mortality rates currently ranging from 30 to 90%. Unfortunately, there is no efficacious human therapy or vaccine available to treat disease caused by either Ebola or Marburg virus infection. Expression of the filovirus matrix protein, VP40, is sufficient to drive spontaneous production and release of virus-like particles (VLPs) that resemble the distinctively filamentous infectious virions. The addition of other filovirus proteins, including virion proteins (VP)24, 30 and 35 and glycoprotein, increases the efficiency of VLP production and results in particles containing multiple filovirus antigens. Vaccination with Ebola or Marburg VLPs containing glycoprotein and VP40 completely protects rodents from lethal challenge with the homologous virus. These candidate vaccines are currently being tested for immunogenicity and efficacy in nonhuman primates. Furthermore, the Ebola and Marburg VLPs are being used as a surrogate model to further understand the filovirus life cycle, with the goal of developing rationally designed vaccines and therapeutics. Thus, in addition to their use as a vaccine, VLPs are currently being used as tools to learn lessons about filovirus pathogenesis, immunology, replication and assembly requirements.
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Affiliation(s)
- Kelly L Warfield
- United States Army Medical Research Institute of Infectious Diseases, Fort Detrick, MD 21702-5011, USA.
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39
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Noyori O, Nakayama E, Maruyama J, Yoshida R, Takada A. Suppression of Fas-mediated apoptosis via steric shielding by filovirus glycoproteins. Biochem Biophys Res Commun 2013; 441:994-8. [PMID: 24239546 DOI: 10.1016/j.bbrc.2013.11.018] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2013] [Accepted: 11/03/2013] [Indexed: 10/26/2022]
Abstract
Apoptotic death of virus-infected cells is generally thought to be a defense mechanism to limit the spread of infectious virions by eliminating virus-producing cells in host animals. On the other hand, several viruses have been shown to have anti-apoptotic mechanisms to facilitate efficient viral replication and transmission. In this study, we found that the filovirus glycoprotein (GP) expressed on cell surfaces formed a steric shield over the Fas molecule and that GP-expressing cells showed resistance to cell death induced by a Fas agonistic antibody. These results suggest that filovirus GP-mediated steric shielding may interfere with the Fas-induced apoptotic signal transduction in infected cells and serve as an immune evasion mechanism for filoviruses.
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Affiliation(s)
- Osamu Noyori
- Division of Global Epidemiology, Hokkaido University Research Center for Zoonosis Control, Sapporo 001-0020, Japan
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40
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Noyori O, Matsuno K, Kajihara M, Nakayama E, Igarashi M, Kuroda M, Isoda N, Yoshida R, Takada A. Differential potential for envelope glycoprotein-mediated steric shielding of host cell surface proteins among filoviruses. Virology 2013; 446:152-61. [DOI: 10.1016/j.virol.2013.07.029] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2013] [Revised: 05/15/2013] [Accepted: 07/24/2013] [Indexed: 12/21/2022]
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41
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Abstract
Lloviu virus (LLOV), a novel filovirus detected in bats, is phylogenetically distinct from viruses in the genera Ebolavirus and Marburgvirus in the family Filoviridae. While filoviruses are known to cause severe hemorrhagic fever in humans and/or nonhuman primates, LLOV is biologically uncharacterized, since infectious LLOV has never been isolated. To examine the properties of LLOV, we characterized its envelope glycoprotein (GP), which likely plays a key role in viral tropism and pathogenicity. We first found that LLOV GP principally has the same primary structure as the other filovirus GPs. Similar to the other filoviruses, virus-like particles (VLPs) produced by transient expression of LLOV GP, matrix protein, and nucleoprotein in 293T cells had densely arrayed GP spikes on a filamentous particle. Mouse antiserum to LLOV VLP was barely cross-reactive to viruses of the other genera, indicating that LLOV is serologically distinct from the other known filoviruses. For functional study of LLOV GP, we utilized a vesicular stomatitis virus (VSV) pseudotype system and found that LLOV GP requires low endosomal pH and cathepsin L, and that human C-type lectins act as attachment factors for LLOV entry into cells. Interestingly, LLOV GP-pseudotyped VSV infected particular bat cell lines more efficiently than viruses bearing other filovirus GPs. These results suggest that LLOV GP mediates cellular entry in a manner similar to that of the other filoviruses while showing preferential tropism for some bat cells.
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42
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Abstract
A number of advances in recent years have significantly furthered our understanding of filovirus attachment and cellular tropism. For example, several cell-surface molecules have been identified as attachment factors with the potential to facilitate the in vivo targeting of particular cell types such as macrophages and hepatic cells. Furthermore, our knowledge of internalization and subsequent events during filovirus entry has also been widened, adding new variations to the paradigms for viral entry established for HIV and influenza. In particular, host cell factors such as endosomal proteases and the intracellular receptor Niemann-Pick C1 are now known to play a vital role in activating the membrane fusion potential of filovirus glycoproteins.
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Affiliation(s)
- Stefan Pöhlmann
- grid.10423.340000000095299877Institute for Virology, Hannover Medical School, Hannover, Germany ,grid.418215.b0000000085027018German Primate Center, Göttingen, Germany
| | - Graham Simmons
- grid.266102.10000000122976811Blood Systems Research Institute, and Department of Laboratory Medicine, University of California San Francisco, San Francisco, California USA
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43
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Cellular factors implicated in filovirus entry. Adv Virol 2013; 2013:487585. [PMID: 23365575 PMCID: PMC3556833 DOI: 10.1155/2013/487585] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2012] [Revised: 12/17/2012] [Accepted: 12/18/2012] [Indexed: 12/11/2022] Open
Abstract
Although filoviral infections are still occurring in different parts of the world, there are no effective preventive or treatment strategies currently available against them. Not only do filoviruses cause a deadly infection, but they also have the potential of being used as biological weapons. This makes it imperative to comprehensively study these viruses in order to devise effective strategies to prevent the occurrence of these infections. Entry is the foremost step in the filoviral replication cycle and different studies have reported the involvement of a myriad of cellular factors including plasma membrane components, cytoskeletal proteins, endosomal components, and cytosolic factors in this process. Signaling molecules such as the TAM family of receptor tyrosine kinases comprising of Tyro3, Axl, and Mer have also been implicated as putative entry factors. Additionally, filoviruses are suggested to bind to a common receptor and recent studies have proposed T-cell immunoglobulin and mucin domain 1 (TIM-1) and Niemann-Pick C1 (NPC1) as potential receptor candidates. This paper summarizes the existing literature on filoviral entry with a special focus on cellular factors involved in this process and also highlights some fundamental questions. Future research aimed at answering these questions could be very useful in designing novel antiviral therapeutics.
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44
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Kajihara M, Nakayama E, Marzi A, Igarashi M, Feldmann H, Takada A. Novel mutations in Marburg virus glycoprotein associated with viral evasion from antibody mediated immune pressure. J Gen Virol 2013; 94:876-883. [PMID: 23288419 DOI: 10.1099/vir.0.049114-0] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Marburg virus (MARV) and Ebola virus, members of the family Filoviridae, cause lethal haemorrhagic fever in humans and non-human primates. Although the outbreaks are concentrated mainly in Central Africa, these viruses are potential agents of imported infectious diseases and bioterrorism in non-African countries. Recent studies demonstrated that non-human primates passively immunized with virus-specific antibodies were successfully protected against fatal filovirus infection, highlighting the important role of antibodies in protective immunity for this disease. However, the mechanisms underlying potential evasion from antibody mediated immune pressure are not well understood. To analyse possible mutations involved in immune evasion in the MARV envelope glycoprotein (GP) which is the major target of protective antibodies, we selected escape mutants of recombinant vesicular stomatitis virus (rVSV) expressing MARV GP (rVSVΔG/MARVGP) by using two GP-specific mAbs, AGP127-8 and MGP72-17, which have been previously shown to inhibit MARV budding. Interestingly, several rVSVΔG/MARVGP variants escaping from the mAb pressure-acquired amino acid substitutions in the furin-cleavage site rather than in the mAb-specific epitopes, suggesting that these epitopes are recessed, not exposed on the uncleaved GP molecule, and therefore inaccessible to the mAbs. More surprisingly, some variants escaping mAb MGP72-17 lacked a large proportion of the mucin-like region of GP, indicating that these mutants efficiently escaped the selective pressure by deleting the mucin-like region including the mAb-specific epitope. Our data demonstrate that MARV GP possesses the potential to evade antibody mediated immune pressure due to extraordinary structural flexibility and variability.
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Affiliation(s)
- Masahiro Kajihara
- Division of Global Epidemiology, Hokkaido University Research Center for Zoonosis Control, Sapporo 001-0020, Japan
| | - Eri Nakayama
- Division of Global Epidemiology, Hokkaido University Research Center for Zoonosis Control, Sapporo 001-0020, Japan
| | - Andrea Marzi
- Laboratory of Virology, Division of Intramural Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rocky Mountain Laboratories, Hamilton, Montana, USA
| | - Manabu Igarashi
- Division of Bioinformatics, Hokkaido University Research Center for Zoonosis Control, Sapporo 001-0020, Japan
| | - Heinz Feldmann
- Laboratory of Virology, Division of Intramural Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rocky Mountain Laboratories, Hamilton, Montana, USA
| | - Ayato Takada
- School of Veterinary Medicine, the University of Zambia, P. O. Box 32379, Lusaka, Zambia.,Division of Global Epidemiology, Hokkaido University Research Center for Zoonosis Control, Sapporo 001-0020, Japan
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Mittler E, Kolesnikova L, Herwig A, Dolnik O, Becker S. Assembly of the Marburg virus envelope. Cell Microbiol 2012. [PMID: 23186212 DOI: 10.1111/cmi.12076] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
The key player to assemble the filamentous Marburg virus particles is the matrix protein VP40 which orchestrates recruitment of nucleocapsid complexes and the viral glycoprotein GP to the budding sites at the plasma membrane. Here, VP40 induces the formation of the viral particles, determines their morphology and excludes cellular proteins from the virions. Budding takes place at filopodia in non-polarized cells and at the basolateral cell pole in polarized epithelial cells. Molecular basis of how VP40 exerts its multifunctional role in these different processes is currently under investigation. Here we summarize recent data on structure-function relationships of VP40 and GP in connection with their function in assembly. Questions concerning the complex particle assembly, budding and release remaining enigmatic are addressed. Cytoplasmic domains of viral surface proteins often serve as a connection to the viral matrix protein or as binding sites for further viral or cellular proteins. A cooperation of MARV GP and VP40 building up the viral envelope can be proposed and is discussed in more detail in this review, as the cytoplasmic domain of GP represents an obvious interaction candidate because of its localization adjacent to the VP40 layer. Interestingly, truncation of the short cytoplasmic domain of GP neither inhibited interaction with VP40 nor incorporation of GP into progeny viral particles. Based on reverse genetics we generated recombinant virions expressing a GP mutant without the cytoplasmic tail. Investigations revealed attenuation in virus growth and an obvious defect in entry. Further investigations showed that the truncation of the cytoplasmic domain of GP impaired the structural integrity of the ectodomain, whichconsequently had impact on entry steps downstream of virus binding. Our data indicated that changes in the cytoplasmic domain are relayed over the lipid membrane to alter the function of the ectodomain.
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Affiliation(s)
- Eva Mittler
- Institute of Virology, Philipps University Marburg, Hans-Meerwein-Strasse 2, 35043 Marburg, Germany
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46
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Inhibition of Marburg virus budding by nonneutralizing antibodies to the envelope glycoprotein. J Virol 2012; 86:13467-74. [PMID: 23035224 DOI: 10.1128/jvi.01896-12] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The envelope glycoprotein (GP) of Marburg virus (MARV) and Ebola virus (EBOV) is responsible for virus entry into host cells and is known as the only target of neutralizing antibodies. While knowledge about EBOV-neutralizing antibodies and the mechanism for the neutralization of infectivity is being accumulated gradually, little is known about antibodies that can efficiently regulate MARV infectivity. Here we show that MARV GP-specific monoclonal antibodies AGP127-8 (IgG1) and MGP72-17 (IgM), which do not inhibit the GP-mediated entry of MARV into host cells, drastically reduced the budding and release of progeny viruses from infected cells. These antibodies similarly inhibited the formation of virus-like particles (VLPs) consisting of GP, the viral matrix protein, and nucleoprotein, whereas the Fab fragment of AGP127-8 showed no inhibitory effect. Morphological analyses revealed that filamentous VLPs were bunched on the surface of VLP-producing cells cultured in the presence of the antibodies. These results demonstrate a novel mechanism of the antibody-mediated inhibition of MARV budding, in which antibodies arrest unformed virus particles on the cell surface. Our data lead to the idea that such antibodies, like classical neutralizing antibodies, contribute to protective immunity against MARV and that the "classical" neutralizing activity is not the only indicator of a protective antibody that may be available for prophylactic and therapeutic use.
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47
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Abstract
In 1967, the first reported filovirus hemorrhagic fever outbreak took place in Germany and the former Yugoslavia. The causative agent that was identified during this outbreak, Marburg virus, is one of the most deadly human pathogens. This article provides a comprehensive overview of our current knowledge about Marburg virus disease ranging from ecology to pathogenesis and molecular biology.
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Affiliation(s)
- Kristina Brauburger
- Department of Microbiology, School of Medicine and National Emerging Infectious Diseases Laboratories Institute, Boston University, Boston, MA 02118, USA.
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48
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Becker GL, Lu Y, Hardes K, Strehlow B, Levesque C, Lindberg I, Sandvig K, Bakowsky U, Day R, Garten W, Steinmetzer T. Highly potent inhibitors of proprotein convertase furin as potential drugs for treatment of infectious diseases. J Biol Chem 2012; 287:21992-2003. [PMID: 22539349 DOI: 10.1074/jbc.m111.332643] [Citation(s) in RCA: 87] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Optimization of our previously described peptidomimetic furin inhibitors was performed and yielded several analogs with a significantly improved activity. The most potent compounds containing an N-terminal 4- or 3-(guanidinomethyl)phenylacetyl residue inhibit furin with K(i) values of 16 and 8 pM, respectively. These analogs inhibit other proprotein convertases, such as PC1/3, PC4, PACE4, and PC5/6, with similar potency, whereas PC2, PC7, and trypsin-like serine proteases are poorly affected. Incubation of selected compounds with Madin-Darby canine kidney cells over a period of 96 h revealed that they exhibit great stability, making them suitable candidates for further studies in cell culture. Two of the most potent derivatives were used to inhibit the hemagglutinin cleavage and viral propagation of a highly pathogenic avian H7N1 influenza virus strain. The treatment with inhibitor 24 (4-(guanidinomethyl)phenylacetyl-Arg-Val-Arg-4-amidinobenzylamide) resulted in significantly delayed virus propagation compared with an inhibitor-free control. The same analog was also effective in inhibiting Shiga toxin activation in HEp-2 cells. This antiviral effect, as well as the protective effect against a bacterial toxin, suggests that inhibitors of furin or furin-like proprotein convertases could represent promising lead structures for future drug development, in particular for the treatment of infectious diseases.
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Affiliation(s)
- Gero L Becker
- Institute of Pharmaceutical Chemistry, Philipps University, 35032 Marburg, Germany
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Affiliation(s)
- Andrew W Artenstein
- Center for Biodefense and Emerging Pathogens, Department of Medicine, Memorial Hospital of Rhode Island, Pawtucket 02860, USA.
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50
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Ebolavirus delta-peptide immunoadhesins inhibit marburgvirus and ebolavirus cell entry. J Virol 2011; 85:8502-13. [PMID: 21697477 DOI: 10.1128/jvi.02600-10] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
With the exception of Reston and Lloviu viruses, filoviruses (marburgviruses, ebolaviruses, and "cuevaviruses") cause severe viral hemorrhagic fevers in humans. Filoviruses use a class I fusion protein, GP(1,2), to bind to an unknown, but shared, cell surface receptor to initiate virus-cell fusion. In addition to GP(1,2), ebolaviruses and cuevaviruses, but not marburgviruses, express two secreted glycoproteins, soluble GP (sGP) and small soluble GP (ssGP). All three glycoproteins have identical N termini that include the receptor-binding region (RBR) but differ in their C termini. We evaluated the effect of the secreted ebolavirus glycoproteins on marburgvirus and ebolavirus cell entry, using Fc-tagged recombinant proteins. Neither sGP-Fc nor ssGP-Fc bound to filovirus-permissive cells or inhibited GP(1,2)-mediated cell entry of pseudotyped retroviruses. Surprisingly, several Fc-tagged Δ-peptides, which are small C-terminal cleavage products of sGP secreted by ebolavirus-infected cells, inhibited entry of retroviruses pseudotyped with Marburg virus GP(1,2), as well as Marburg virus and Ebola virus infection in a dose-dependent manner and at low molarity despite absence of sequence similarity to filovirus RBRs. Fc-tagged Δ-peptides from three ebolaviruses (Ebola virus, Sudan virus, and Taï Forest virus) inhibited GP(1,2)-mediated entry and infection of viruses comparably to or better than the Fc-tagged RBRs, whereas the Δ-peptide-Fc of an ebolavirus nonpathogenic for humans (Reston virus) and that of an ebolavirus with lower lethality for humans (Bundibugyo virus) had little effect. These data indicate that Δ-peptides are functional components of ebolavirus proteomes. They join cathepsins and integrins as novel modulators of filovirus cell entry, might play important roles in pathogenesis, and could be exploited for the synthesis of powerful new antivirals.
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