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Shalamova L, Barth P, Pickin MJ, Kouti K, Ott B, Humpert K, Janssen S, Lorenzo G, Brun A, Goesmann A, Hain T, Hartmann RK, Rossbach O, Weber F. Nucleocapsids of the Rift Valley fever virus ambisense S segment contain an exposed RNA element in the center that overlaps with the intergenic region. Nat Commun 2024; 15:7602. [PMID: 39217162 PMCID: PMC11365940 DOI: 10.1038/s41467-024-52058-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2023] [Accepted: 08/21/2024] [Indexed: 09/04/2024] Open
Abstract
Rift Valley fever virus (RVFV) is a mosquito-borne zoonotic pathogen. Its RNA genome consists of two negative-sense segments (L and M) with one gene each, and one ambisense segment (S) with two opposing genes separated by the noncoding "intergenic region" (IGR). These vRNAs and the complementary cRNAs are encapsidated by nucleoprotein (N). Using iCLIP2 (individual-nucleotide resolution UV crosslinking and immunoprecipitation) to map all N-vRNA and N-cRNA interactions, we detect N coverage along the L and M segments. However, the S segment vRNA and cRNA each contain approximately 100 non-encapsidated nucleotides stretching from the IGR into the 5'-adjacent reading frame. These exposed regions are RNase-sensitive and predicted to form stem-loop structures with the mRNA transcription termination motif positioned near the top. Moreover, optimal S segment transcription and replication requires the entire exposed region rather than only the IGR. Thus, the RVFV S segment contains a central, non-encapsidated RNA region with a functional role.
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Affiliation(s)
- Lyudmila Shalamova
- Institute for Virology, FB10-Veterinary Medicine, Justus-Liebig University, Giessen, Germany
| | - Patrick Barth
- Bioinformatics & Systems Biology, Justus-Liebig University, Giessen, Germany
- Cell Biology and Plant Biochemistry, University of Regensburg, Regensburg, Germany
| | - Matthew J Pickin
- Institute for Virology, FB10-Veterinary Medicine, Justus-Liebig University, Giessen, Germany
| | - Kiriaki Kouti
- Institute for Virology, FB10-Veterinary Medicine, Justus-Liebig University, Giessen, Germany
| | - Benjamin Ott
- Institute for Medical Microbiology, FB11-Medicine, Justus-Liebig University, Giessen, Germany
| | - Katharina Humpert
- Institute for Medical Microbiology, FB11-Medicine, Justus-Liebig University, Giessen, Germany
- Institute of Molecular Oncology, Genomics Core Facility, Philipps-University, Marburg, Germany
| | - Stefan Janssen
- Algorithmic Bioinformatics, Justus-Liebig University, Giessen, Germany
| | - Gema Lorenzo
- Centro de Investigación en Sanidad Animal (CISA-INIA/CSIC), Valdeolmos, Madrid, Spain
| | - Alejandro Brun
- Centro de Investigación en Sanidad Animal (CISA-INIA/CSIC), Valdeolmos, Madrid, Spain
| | - Alexander Goesmann
- Bioinformatics & Systems Biology, Justus-Liebig University, Giessen, Germany
| | - Torsten Hain
- Institute for Medical Microbiology, FB11-Medicine, Justus-Liebig University, Giessen, Germany
| | - Roland K Hartmann
- Institute of Pharmaceutical Chemistry, Philipps-University Marburg, Marburg, Germany
| | - Oliver Rossbach
- Institute for Biochemistry, FB 08-Biology and Chemistry, Justus-Liebig University, Giessen, Germany
| | - Friedemann Weber
- Institute for Virology, FB10-Veterinary Medicine, Justus-Liebig University, Giessen, Germany.
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2
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Muralitharan I, Sahoo AK, Augusthian PD, Samal A. Computational prediction of phytochemical inhibitors against the cap-binding domain of Rift Valley fever virus. Mol Divers 2024; 28:2637-2650. [PMID: 37481749 DOI: 10.1007/s11030-023-10702-x] [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: 05/06/2023] [Accepted: 07/16/2023] [Indexed: 07/25/2023]
Abstract
Rift Valley fever is a zoonotic disease that can spread through livestock and mosquitoes, and its symptoms include retinitis, photophobia, hemorrhagic fever and neurological effects. The World Health Organization has identified Rift Valley fever as one of the viral infections that has potential to cause a future epidemic. Hence, efforts are urgently needed toward development of therapeutics and vaccine against this infectious disease. Notably, the causative virus namely, the Rift Valley fever virus (RVFV), utilizes the cap-snatching mechanism for viral transcription, rendering its cap-binding domain (CBD) as an effective antiviral target. To date, there are no published studies towards identification of potential small molecule inhibitors for the CBD of RVFV. Here, we employ a virtual screening workflow comprising of molecular docking and molecular dynamics (MD) simulation, to identify 5 potential phytochemical inhibitors of the CBD of RVFV. These 5 phytochemical inhibitors can be sourced from Indian medicinal plants, Ferula assa-foetida, Glycyrrhiza glabra and Leucas cephalotes, used in traditional medicine. In sum, the 5 phytochemical inhibitors of the CBD of RVFV identified by this purely computational study are promising drug lead molecules which can be considered for detailed experimental validation against RVFV infection.
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Affiliation(s)
- Ishwarya Muralitharan
- Computational Biology Group, The Institute of Mathematical Sciences (IMSc), CIT Campus, Taramani, Chennai, 600113, India
| | - Ajaya Kumar Sahoo
- Computational Biology Group, The Institute of Mathematical Sciences (IMSc), CIT Campus, Taramani, Chennai, 600113, India
- Homi Bhabha National Institute (HBNI), Mumbai, 400094, India
| | - Priya Dharshini Augusthian
- Computational Biology Group, The Institute of Mathematical Sciences (IMSc), CIT Campus, Taramani, Chennai, 600113, India
| | - Areejit Samal
- Computational Biology Group, The Institute of Mathematical Sciences (IMSc), CIT Campus, Taramani, Chennai, 600113, India.
- Homi Bhabha National Institute (HBNI), Mumbai, 400094, India.
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3
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Subramani C, Sharma G, Chaira T, Barman TK. High content screening strategies for large-scale compound libraries with a focus on high-containment viruses. Antiviral Res 2024; 221:105764. [PMID: 38008193 DOI: 10.1016/j.antiviral.2023.105764] [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: 09/11/2023] [Revised: 11/14/2023] [Accepted: 11/19/2023] [Indexed: 11/28/2023]
Abstract
A majority of viral diseases do not have FDA-approved drugs. The recent outbreaks caused by SARS-CoV-2, monkeypox, and Sudan ebolavirus have exposed the critical need for rapid screening and identification of antiviral compounds against emerging/re-emerging viral pathogens. A high-content screening (HCS) platform is becoming an essential part of the drug discovery process, thanks to developments in image acquisition and analysis. While HCS has several advantages, its full potential has not been realized in antiviral drug discovery compared to conventional drug screening approaches, such as fluorescence or luminescence-based microplate assays. Therefore, this review aims to summarize HCS workflow, strategies, and developments in image-based drug screening, focusing on high-containment viruses.
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Affiliation(s)
- Chandru Subramani
- Department of Pathology, University of Texas Medical Branch, Galveston, TX, USA; Galveston National Laboratory, Galveston, TX, USA
| | - Ghanshyam Sharma
- Regional Centre for Biotechnology, NCR Biotech Science Cluster, Faridabad, Haryana, India
| | - Tridib Chaira
- Department of Pharmacology, SGT University, Gurugram, Haryana, India
| | - Tarani Kanta Barman
- Department of Pathology, University of Texas Medical Branch, Galveston, TX, USA; Galveston National Laboratory, Galveston, TX, USA.
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4
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Hamele CE, Spurrier MA, Leonard RA, Heaton NS. Segmented, Negative-Sense RNA Viruses of Humans: Genetic Systems and Experimental Uses of Reporter Strains. Annu Rev Virol 2023; 10:261-282. [PMID: 37774125 PMCID: PMC10795101 DOI: 10.1146/annurev-virology-111821-120445] [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: 10/01/2023]
Abstract
Negative-stranded RNA viruses are a large group of viruses that encode their genomes in RNA across multiple segments in an orientation antisense to messenger RNA. Their members infect broad ranges of hosts, and there are a number of notable human pathogens. Here, we examine the development of reverse genetic systems as applied to these virus families, emphasizing conserved approaches illustrated by some of the prominent members that cause significant human disease. We also describe the utility of their genetic systems in the development of reporter strains of the viruses and some biological insights made possible by their use. To conclude the review, we highlight some possible future uses of reporter viruses that not only will increase our basic understanding of how these viruses replicate and cause disease but also could inform the development of new approaches to therapeutically intervene.
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Affiliation(s)
- Cait E Hamele
- Department of Molecular Genetics and Microbiology, Duke University School of Medicine, Durham, North Carolina, USA;
| | - M Ariel Spurrier
- Department of Molecular Genetics and Microbiology, Duke University School of Medicine, Durham, North Carolina, USA;
| | - Rebecca A Leonard
- Department of Molecular Genetics and Microbiology, Duke University School of Medicine, Durham, North Carolina, USA;
| | - Nicholas S Heaton
- Department of Molecular Genetics and Microbiology, Duke University School of Medicine, Durham, North Carolina, USA;
- Duke Human Vaccine Institute, Duke University School of Medicine, Durham, North Carolina, USA
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5
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Islam K, Carlsson M, Enquist PA, Qian W, Marttila M, Strand M, Ahlm C, Evander M. Structural Modifications and Biological Evaluations of Rift Valley Fever Virus Inhibitors Identified from Chemical Library Screening. ACS OMEGA 2022; 7:6854-6868. [PMID: 35252679 PMCID: PMC8892858 DOI: 10.1021/acsomega.1c06513] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/19/2021] [Accepted: 02/04/2022] [Indexed: 06/14/2023]
Abstract
The Rift Valley fever virus (RVFV) is an emerging high-priority pathogen endemic in Africa with pandemic potential. There is no specific treatment or approved antiviral drugs for the RVFV. We previously developed a cell-based high-throughput assay to screen small molecules targeting the RVFV and identified a potential effective antiviral compound (1-N-(2-(biphenyl-4-yloxy)ethyl)propane-1,3-diamine) as a lead compound. Here, we investigated how structural modifications of the lead compound affected the biological properties and the antiviral effect against the RVFV. We found that the length of the 2-(3-aminopropylamino)ethyl chain of the compound was important for the compound to retain its antiviral activity. The antiviral activity was similar when the 2-(3-aminopropylamino)ethyl chain was replaced with a butyl piperazine chain. However, we could improve the cytotoxicity profile of the lead compound by changing the phenyl piperazine linker from the para-position (compound 9a) to the meta-position (compound 13a). Results from time-of-addition studies suggested that compound 13a might be active during virus post-entry and/or the replication phase of the virus life cycle and seemed to affect the K+ channel. The modifications improved the properties of our lead compound, and our data suggest that 13a is a promising candidate to evaluate further as a therapeutic agent for RVFV infection.
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Affiliation(s)
- Koushikul Islam
- Department
of Clinical Microbiology, Umeå University, Umeå 901 85, Sweden
| | - Marcus Carlsson
- Department
of Chemistry, Umeå University, Umeå 901 87, Sweden
| | | | - Weixing Qian
- Department
of Chemistry, Umeå University, Umeå 901 87, Sweden
| | - Marko Marttila
- Department
of Clinical Microbiology, Umeå University, Umeå 901 85, Sweden
| | - Mårten Strand
- Department
of Clinical Microbiology, Umeå University, Umeå 901 85, Sweden
| | - Clas Ahlm
- Department
of Clinical Microbiology, Umeå University, Umeå 901 85, Sweden
| | - Magnus Evander
- Department
of Clinical Microbiology, Umeå University, Umeå 901 85, Sweden
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6
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Morales Vasquez D, Chiem K, Ye C, Martinez-Sobrido L. Bioluminescent and Fluorescent Reporter-Expressing Recombinant SARS-CoV-2. Methods Mol Biol 2022; 2524:235-248. [PMID: 35821476 DOI: 10.1007/978-1-0716-2453-1_18] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Abstract
Reporter-expressing recombinant severe acute respiratory syndrome coronavirus 2 (rSARS-CoV-2) represents an excellent tool to understand the biology of and ease studying viral infections in vitro and in vivo. The broad range of applications of reporter-expressing recombinant viruses is due to the facilitated expression of fluorescence or bioluminescence readouts. In this chapter, we describe a detailed protocol on the generation of rSARS-CoV-2 expressing Venus, mCherry, and NLuc that represents a valid surrogate to track viral infections.
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Affiliation(s)
| | - Kevin Chiem
- Texas Biomedical Research Institute, San Antonio, TX, USA
| | - Chengjin Ye
- Texas Biomedical Research Institute, San Antonio, TX, USA
| | - Luis Martinez-Sobrido
- Texas Biomedical Research Institute, San Antonio, TX, USA.
- Department of Disease Prevention and Intervention, Texas Biomedical Research Institute, San Antonio, TX, USA.
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7
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Abstract
RNA-activated protein kinase (PKR) is one of the most powerful antiviral defense factors of the mammalian host. PKR acts by phosphorylating mRNA translation initiation factor eIF2α, thereby converting it from a cofactor to an inhibitor of mRNA translation that strongly binds to initiation factor eIF2B. To sustain synthesis of their proteins, viruses are known to counteract this on the level of PKR or eIF2α or by circumventing initiation factor-dependent translation altogether. Here, we report a different PKR escape strategy executed by sandfly fever Sicilian virus (SFSV), a member of the increasingly important group of phleboviruses. We found that the nonstructural protein NSs of SFSV binds to eIF2B and protects it from inactivation by PKR-generated phospho-eIF2α. Protein synthesis is hence maintained and the virus can replicate despite ongoing full-fledged PKR signaling in the infected cells. Thus, SFSV has evolved a unique strategy to escape the powerful antiviral PKR. RNA-activated protein kinase (PKR) is a major innate immune factor that senses viral double-stranded RNA (dsRNA) and phosphorylates eukaryotic initiation factor (eIF) 2α. Phosphorylation of the α subunit converts the eIF2αβγ complex into a stoichiometric inhibitor of eukaryotic initiation factor eIF2B, thus halting mRNA translation. To escape this protein synthesis shutoff, viruses have evolved countermechanisms such as dsRNA sequestration, eIF-independent translation by an internal ribosome binding site, degradation of PKR, or dephosphorylation of PKR or of phospho-eIF2α. Here, we report that sandfly fever Sicilian phlebovirus (SFSV) confers such a resistance without interfering with PKR activation or eIF2α phosphorylation. Rather, SFSV expresses a nonstructural protein termed NSs that strongly binds to eIF2B. Although NSs still allows phospho-eIF2α binding to eIF2B, protein synthesis and virus replication are unhindered. Hence, SFSV encodes a unique PKR antagonist that acts by rendering eIF2B resistant to the inhibitory action of bound phospho-eIF2α.
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8
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Wendt L, Bostedt L, Hoenen T, Groseth A. High-throughput screening for negative-stranded hemorrhagic fever viruses using reverse genetics. Antiviral Res 2019; 170:104569. [PMID: 31356830 DOI: 10.1016/j.antiviral.2019.104569] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2019] [Revised: 06/28/2019] [Accepted: 07/25/2019] [Indexed: 02/06/2023]
Abstract
Viral hemorrhagic fevers (VHFs) cause thousands of fatalities every year, but the treatment options for their management remain very limited. In particular, the development of therapeutic interventions is restricted by the lack of commercial viability of drugs targeting individual VHF agents. This makes approaches like drug repurposing and/or the identification of broad range therapies (i.e. those directed at host responses or common proviral factors) highly attractive. However, the identification of candidates for such antiviral repurposing or of host factors/pathways important for the virus life cycle is reliant on high-throughput screening (HTS). Recently, such screening work has been increasingly facilitated by the availability of reverse genetics-based approaches, including tools such as full-length clone (FLC) systems to generate reporter-expressing viruses or various life cycle modelling (LCM) systems, many of which have been developed and/or greatly improved during the last years. In particular, since LCM systems are capable of modelling specific steps in the life cycle, they are a valuable tool for both targeted screening (i.e. for inhibitors of a specific pathway) and mechanism of action studies. This review seeks to summarize the currently available reverse genetics systems for negative-sense VHF causing viruses (i.e. arenaviruses, bunyaviruses and filoviruses), and to highlight the recent advancements made in applying these systems for HTS to identify either antivirals or new virus-host interactions that might hold promise for the development of future treatments for the infections caused by these deadly but neglected virus groups.
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Affiliation(s)
- Lisa Wendt
- Institute of Molecular Virology and Cell Biology, Friedrich-Loeffler-Institut, Greifswald, Insel Riems, Germany
| | - Linus Bostedt
- Junior Research Group - Arenavirus Biology, Friedrich-Loeffler-Institut, Greifswald, Insel Riems, Germany
| | - Thomas Hoenen
- Institute of Molecular Virology and Cell Biology, Friedrich-Loeffler-Institut, Greifswald, Insel Riems, Germany.
| | - Allison Groseth
- Junior Research Group - Arenavirus Biology, Friedrich-Loeffler-Institut, Greifswald, Insel Riems, Germany.
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9
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Jia K, Yuan Y, Liu W, Liu L, Qin Q, Yi M. Identification of Inhibitory Compounds Against Singapore Grouper Iridovirus Infection by Cell Viability-Based Screening Assay and Droplet Digital PCR. MARINE BIOTECHNOLOGY (NEW YORK, N.Y.) 2018; 20:35-44. [PMID: 29209860 DOI: 10.1007/s10126-017-9785-1] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/28/2017] [Accepted: 11/20/2017] [Indexed: 06/07/2023]
Abstract
Singapore grouper iridovirus (SGIV) is one of the major causative agents of fish diseases and has caused significant economic losses in the aquaculture industry. There is currently no commercial vaccine or effective antiviral treatment against SGIV infection. Annually, an increasing number of small molecule compounds from various sources have been produced, and many are proved to be potential inhibitors against viruses. Here, a high-throughput in vitro cell viability-based screening assay was developed to identify antiviral compounds against SGIV using the luminescent-based CellTiter-Glo reagent in cultured grouper spleen cells by quantificational measurement of the cytopathic effects induced by SGIV infection. This assay was utilized to screen for potential SGIV inhibitors from five customized compounds which had been reported to be capable of inhibiting other viruses and 30 compounds isolated from various marine organisms, and three of them [ribavirin, harringtonine, and 2-hydroxytetradecanoic acid (2-HOM)] were identified to be effective on inhibiting SGIV infection, which was further confirmed with droplet digital PCR (ddPCR). In addition, the ddPCR results revealed that ribavirin and 2-HOM inhibited SGIV replication and entry in a dose-dependent manner, and harringtonine could reduce SGIV replication rather than entry at the working concentration without significant toxicity. These findings provided an easy and reliable cell viability-based screening assay to identify compounds with anti-SGIV effect and a way of studying the anti-SGIV mechanism of compounds.
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Affiliation(s)
- Kuntong Jia
- Guangdong Provincial Key Laboratory of Marine Resources and Coastal Engineering, Zhuhai Key Laboratory of Marine Bioresources and Environment, School of Marine Sciences, Sun Yat-sen University, Guangzhou, Guangdong, China
| | - Yongming Yuan
- Department of Biological Sciences, National University of Singapore, Science Drive 4, Singapore, 117543, Singapore
| | - Wei Liu
- Guangdong Provincial Key Laboratory of Marine Resources and Coastal Engineering, Zhuhai Key Laboratory of Marine Bioresources and Environment, School of Marine Sciences, Sun Yat-sen University, Guangzhou, Guangdong, China
| | - Lan Liu
- Guangdong Provincial Key Laboratory of Marine Resources and Coastal Engineering, Zhuhai Key Laboratory of Marine Bioresources and Environment, School of Marine Sciences, Sun Yat-sen University, Guangzhou, Guangdong, China
| | - Qiwei Qin
- College of Marine Sciences, South China Agricultural University, Guangzhou, 510642, China.
| | - Meisheng Yi
- Guangdong Provincial Key Laboratory of Marine Resources and Coastal Engineering, Zhuhai Key Laboratory of Marine Bioresources and Environment, School of Marine Sciences, Sun Yat-sen University, Guangzhou, Guangdong, China.
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10
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Anti-Rift Valley fever virus activity in vitro, pre-clinical pharmacokinetics and oral bioavailability of benzavir-2, a broad-acting antiviral compound. Sci Rep 2018; 8:1925. [PMID: 29386590 PMCID: PMC5792431 DOI: 10.1038/s41598-018-20362-9] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2017] [Accepted: 01/17/2018] [Indexed: 12/24/2022] Open
Abstract
Rift Valley fever virus (RVFV) is a mosquito-borne hemorrhagic fever virus affecting both humans and animals with severe morbidity and mortality and is classified as a potential bioterror agent due to the possible aerosol transmission. At present there is no human vaccine or antiviral therapy available. Thus, there is a great need to develop new antivirals for treatment of RVFV infections. Benzavir-2 was previously identified as potent inhibitor of human adenovirus, herpes simplex virus type 1, and type 2. Here we assess the anti-RVFV activity of benzavir-2 together with four structural analogs and determine pre-clinical pharmacokinetic parameters of benzavir-2. In vitro, benzavir-2 efficiently inhibited RVFV infection, viral RNA production and production of progeny viruses. In vitro, benzavir-2 displayed satisfactory solubility, good permeability and metabolic stability. In mice, benzavir-2 displayed oral bioavailability with adequate maximum serum concentration. Oral administration of benzavir-2 formulated in peanut butter pellets gave high systemic exposure without any observed toxicity in mice. To summarize, our data demonstrated potent anti-RVFV activity of benzavir-2 in vitro together with a promising pre-clinical pharmacokinetic profile. This data support further exploration of the antiviral activity of benzavir-2 in in vivo efficacy models that may lead to further drug development for human use.
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11
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Atkins C, Freiberg AN. Recent advances in the development of antiviral therapeutics for Rift Valley fever virus infection. Future Virol 2017; 12:651-665. [PMID: 29181086 DOI: 10.2217/fvl-2017-0060] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2017] [Accepted: 07/26/2017] [Indexed: 12/25/2022]
Abstract
Rift Valley fever virus (RVFV) is a mosquito-borne bunyavirus endemic to sub-Saharan Africa and the Arabian Peninsula and the etiological agent of Rift Valley fever. Rift Valley fever is a disease of major public health and economic concern, affecting livestock and humans. In ruminants, RVFV infection is characterized by high mortality rates in newborns and near 100% abortion rates in pregnant animals. Infection in humans is typically manifested as a self-limiting febrile illness, but can lead to severe and fatal hepatitis, encephalitis, hemorrhagic fever or retinitis with partial or complete blindness. Currently, there are no specific treatment options available for RVFV infection. This review presents a summary of the therapeutic approaches that have been explored on the treatment of RVFV infection.
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Affiliation(s)
- Colm Atkins
- Department of Pathology, The University of Texas Medical Branch, 301 University Boulevard, Galveston, TX 77555, USA.,Department of Pathology, The University of Texas Medical Branch, 301 University Boulevard, Galveston, TX 77555, USA
| | - Alexander N Freiberg
- Department of Pathology, The University of Texas Medical Branch, 301 University Boulevard, Galveston, TX 77555, USA.,The Sealy Center for Vaccine Development, The University of Texas Medical Branch, 301 University Boulevard, Galveston, TX 77555, USA.,The Center for Biodefense & Emerging Infectious Diseases, The University of Texas Medical Branch, 301 University Boulevard, Galveston, TX 77555, USA.,Department of Pathology, The University of Texas Medical Branch, 301 University Boulevard, Galveston, TX 77555, USA.,The Sealy Center for Vaccine Development, The University of Texas Medical Branch, 301 University Boulevard, Galveston, TX 77555, USA.,The Center for Biodefense & Emerging Infectious Diseases, The University of Texas Medical Branch, 301 University Boulevard, Galveston, TX 77555, USA
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12
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A Genome-Wide RNA Interference Screen Identifies a Role for Wnt/β-Catenin Signaling during Rift Valley Fever Virus Infection. J Virol 2016; 90:7084-7097. [PMID: 27226375 PMCID: PMC4984662 DOI: 10.1128/jvi.00543-16] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2016] [Accepted: 05/14/2016] [Indexed: 01/18/2023] Open
Abstract
Rift Valley fever virus (RVFV) is an arbovirus within the Bunyaviridae family capable of causing serious morbidity and mortality in humans and livestock. To identify host factors involved in bunyavirus replication, we employed genome-wide RNA interference (RNAi) screening and identified 381 genes whose knockdown reduced infection. The Wnt pathway was the most represented pathway when gene hits were functionally clustered. With further investigation, we found that RVFV infection activated Wnt signaling, was enhanced when Wnt signaling was preactivated, was reduced with knockdown of β-catenin, and was blocked using Wnt signaling inhibitors. Similar results were found using distantly related bunyaviruses La Crosse virus and California encephalitis virus, suggesting a conserved role for Wnt signaling in bunyaviral infection. We propose a model where bunyaviruses activate Wnt-responsive genes to regulate optimal cell cycle conditions needed to promote efficient viral replication. The findings in this study should aid in the design of efficacious host-directed antiviral therapeutics. IMPORTANCE RVFV is a mosquito-borne bunyavirus that is endemic to Africa but has demonstrated a capacity for emergence in new territories (e.g., the Arabian Peninsula). As a zoonotic pathogen that primarily affects livestock, RVFV can also cause lethal hemorrhagic fever and encephalitis in humans. Currently, there are no treatments or fully licensed vaccines for this virus. Using high-throughput RNAi screening, we identified canonical Wnt signaling as an important host pathway regulating RVFV infection. The beneficial role of Wnt signaling was observed for RVFV, along with other disparate bunyaviruses, indicating a conserved bunyaviral replication mechanism involving Wnt signaling. These studies supplement our knowledge of the fundamental mechanisms of bunyavirus infection and provide new avenues for countermeasure development against pathogenic bunyaviruses.
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13
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Making Bunyaviruses Talk: Interrogation Tactics to Identify Host Factors Required for Infection. Viruses 2016; 8:v8050130. [PMID: 27187446 PMCID: PMC4885085 DOI: 10.3390/v8050130] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2016] [Revised: 05/03/2016] [Accepted: 05/06/2016] [Indexed: 12/26/2022] Open
Abstract
The identification of host cellular genes that act as either proviral or antiviral factors has been aided by the development of an increasingly large number of high-throughput screening approaches. Here, we review recent advances in which these new technologies have been used to interrogate host genes for the ability to impact bunyavirus infection, both in terms of technical advances as well as a summary of biological insights gained from these studies.
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