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In the quest for heightened protection against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants, we engineered a prototype vaccine utilizing the plant expression system of Nicotiana benthamiana, to produce a recombinant SARS-CoV-2 virus-like particle (VLP) vaccine presenting the S-protein from the Beta (B.1.351) variant of concern (VOC). This innovative vaccine, formulated with either a squalene oil-in-water emulsion or a synthetic CpG oligodeoxynucleotide adjuvant, demonstrated efficacy in a golden Syrian Hamster challenge model. The Beta VLP vaccine induced a robust humoral immune response, with serum exhibiting neutralization not only against SARS-CoV-2 Beta but also cross-neutralizing Delta and Omicron pseudoviruses. Protective efficacy was demonstrated, evidenced by reduced viral RNA copies and mitigated weight loss and lung damage compared to controls. This compelling data instills confidence in the creation of a versatile platform for the local manufacturing of potential pan-sarbecovirus vaccines, against evolving viral threats.
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COVID-19 , Animales , Cricetinae , Humanos , COVID-19/prevención & control , Mesocricetus , SARS-CoV-2 , Vacunas contra la COVID-19/genética , Glicoproteína de la Espiga del Coronavirus , Anticuerpos Antivirales , Anticuerpos NeutralizantesRESUMEN
Influenza A Virus (IAV) is a recurring respiratory virus with limited availability of antiviral therapies. Understanding host proteins essential for IAV infection can identify targets for alternative host-directed therapies (HDTs). Using affinity purification-mass spectrometry and global phosphoproteomic and protein abundance analyses using three IAV strains (pH1N1, H3N2, H5N1) in three human cell types (A549, NHBE, THP-1), we map 332 IAV-human protein-protein interactions and identify 13 IAV-modulated kinases. Whole exome sequencing of patients who experienced severe influenza reveals several genes, including scaffold protein AHNAK, with predicted loss-of-function variants that are also identified in our proteomic analyses. Of our identified host factors, 54 significantly alter IAV infection upon siRNA knockdown, and two factors, AHNAK and coatomer subunit COPB1, are also essential for productive infection by SARS-CoV-2. Finally, 16 compounds targeting our identified host factors suppress IAV replication, with two targeting CDK2 and FLT3 showing pan-antiviral activity across influenza and coronavirus families. This study provides a comprehensive network model of IAV infection in human cells, identifying functional host targets for pan-viral HDT.
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COVID-19 , Subtipo H5N1 del Virus de la Influenza A , Virus de la Influenza A , Gripe Humana , Humanos , Virus de la Influenza A/genética , Gripe Humana/genética , Subtipo H5N1 del Virus de la Influenza A/genética , Subtipo H3N2 del Virus de la Influenza A/metabolismo , Proteómica , Replicación Viral/genética , SARS-CoV-2 , Antivirales/metabolismo , Interacciones Huésped-Patógeno/genéticaRESUMEN
The SARS-CoV-2 pandemic demonstrated the need for potent and broad-spectrum vaccines. This study reports the development and testing of a lumpy skin disease virus (LSDV)-vectored vaccine against SARS-CoV-2, utilizing stabilized spike and conserved nucleocapsid proteins as antigens to develop robust immunogenicity. Construction of the vaccine (LSDV-SARS2-S,N) was confirmed by polymerase chain reaction (PCR) amplification and sequencing. In vitro characterization confirmed that cells infected with LSDV-SARS2-S,N expressed SARS-CoV-2 spike and nucleocapsid protein. In BALB/c mice, the vaccine elicited high magnitude IFN-γ ELISpot responses (spike: 2808 SFU/106 splenocytes) and neutralizing antibodies (ID50 = 6552). Testing in hamsters, which emulate human COVID-19 disease progression, showed the development of high titers of neutralizing antibodies against the Wuhan and Delta SARS-CoV-2 variants (Wuhan ID50 = 2905; Delta ID50 = 4648). Additionally, hamsters vaccinated with LSDV-SARS2-S,N displayed significantly less weight loss, lung damage, and reduced viral RNA copies following SARS-CoV-2 infection with the Delta variant as compared to controls, demonstrating protection against disease. These data demonstrate that LSDV-vectored vaccines display promise as an effective SARS-CoV-2 vaccine and as a potential vaccine platform for communicable diseases in humans and animals. Further efficacy testing and immune response analysis, particularly in non-human primates, are warranted.
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COVID-19 , Virus de la Dermatosis Nodular Contagiosa , Vacunas , Animales , Cricetinae , Bovinos , Ratones , Humanos , SARS-CoV-2/genética , Vacunas contra la COVID-19 , COVID-19/prevención & control , Anticuerpos Neutralizantes , Ratones Endogámicos BALB C , Proteínas de la Nucleocápside , Anticuerpos Antivirales , Glicoproteína de la Espiga del Coronavirus/genéticaRESUMEN
Molecular farming of vaccines has been heralded as a cheap, safe and scalable production platform. In reality, however, differences in the plant biosynthetic machinery, compared to mammalian cells, can complicate the production of viral glycoproteins. Remodelling the secretory pathway presents an opportunity to support key post-translational modifications, and to tailor aspects of glycosylation and glycosylation-directed folding. In this study, we applied an integrated host and glyco-engineering approach, NXS/T Generation™, to produce a SARS-CoV-2 prefusion spike trimer in Nicotiana benthamiana as a model antigen from an emerging virus. The size exclusion-purified protein exhibited a characteristic prefusion structure when viewed by transmission electron microscopy, and this was indistinguishable from the equivalent mammalian cell-produced antigen. The plant-produced protein was decorated with under-processed oligomannose N-glycans and exhibited a site occupancy that was comparable to the equivalent protein produced in mammalian cell culture. Complex-type glycans were almost entirely absent from the plant-derived material, which contrasted against the predominantly mature, complex glycans that were observed on the mammalian cell culture-derived protein. The plant-derived antigen elicited neutralizing antibodies against both the matched Wuhan and heterologous Delta SARS-CoV-2 variants in immunized hamsters, although titres were lower than those induced by the comparator mammalian antigen. Animals vaccinated with the plant-derived antigen exhibited reduced viral loads following challenge, as well as significant protection from SARS-CoV-2 disease as evidenced by reduced lung pathology, lower viral loads and protection from weight loss. Nonetheless, animals immunized with the mammalian cell-culture-derived protein were better protected in this challenge model suggesting that more faithfully reproducing the native glycoprotein structure and associated glycosylation of the antigen may be desirable.
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Molecular responses to influenza A virus (IAV) infections vary between mammalian species. To identify conserved and species-specific molecular responses, we perform a comparative study of transcriptomic data derived from blood cells, primary epithelial cells, and lung tissues collected from IAV-infected humans, ferrets, and mice. The molecular responses in the human host have unique functions such as antigen processing that are not observed in mice or ferrets. Highly conserved gene coexpression modules across the three species are enriched for IAV infection-induced pathways including cell cycle and interferon (IFN) signaling. TDRD7 is predicted as an IFN-inducible host factor that is up-regulated upon IAV infection in the three species. TDRD7 is required for antiviral IFN response, potentially modulating IFN signaling via the JAK/STAT/IRF9 pathway. Identification of the common and species-specific molecular signatures, networks, and regulators of IAV infection provides insights into host-defense mechanisms and will facilitate the development of novel therapeutic interventions against IAV infection.
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Enfermedades Transmisibles , Virus de la Influenza A , Gripe Humana , Infecciones por Orthomyxoviridae , Animales , Antivirales , Hurones/metabolismo , Humanos , Virus de la Influenza A/fisiología , Gripe Humana/genética , Interferones/metabolismo , Ratones , Infecciones por Orthomyxoviridae/genética , RibonucleoproteínasAsunto(s)
Vacuna nCoV-2019 mRNA-1273/administración & dosificación , Vacuna BNT162/administración & dosificación , COVID-19/epidemiología , ChAdOx1 nCoV-19/administración & dosificación , SARS-CoV-2/patogenicidad , Vacuna nCoV-2019 mRNA-1273/inmunología , Adulto , Vacuna BNT162/inmunología , COVID-19/inmunología , COVID-19/prevención & control , COVID-19/virología , Vacunas contra la COVID-19/inmunología , ChAdOx1 nCoV-19/inmunología , Femenino , Humanos , Inmunización Secundaria , Inmunogenicidad Vacunal , Masculino , SARS-CoV-2/inmunología , SARS-CoV-2/aislamiento & purificación , Carga ViralRESUMEN
A deficient interferon (IFN) response to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection has been implicated as a determinant of severe coronavirus disease 2019 (COVID-19). To identify the molecular effectors that govern IFN control of SARS-CoV-2 infection, we conducted a large-scale gain-of-function analysis that evaluated the impact of human IFN-stimulated genes (ISGs) on viral replication. A limited subset of ISGs were found to control viral infection, including endosomal factors inhibiting viral entry, RNA binding proteins suppressing viral RNA synthesis, and a highly enriched cluster of endoplasmic reticulum (ER)/Golgi-resident ISGs inhibiting viral assembly/egress. These included broad-acting antiviral ISGs and eight ISGs that specifically inhibited SARS-CoV-2 and SARS-CoV-1 replication. Among the broad-acting ISGs was BST2/tetherin, which impeded viral release and is antagonized by SARS-CoV-2 Orf7a protein. Overall, these data illuminate a set of ISGs that underlie innate immune control of SARS-CoV-2/SARS-CoV-1 infection, which will facilitate the understanding of host determinants that impact disease severity and offer potential therapeutic strategies for COVID-19.
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Antígenos CD/genética , Interacciones Huésped-Patógeno/genética , Factores Reguladores del Interferón/genética , Interferón Tipo I/genética , SARS-CoV-2/genética , Proteínas Virales/genética , Animales , Antígenos CD/química , Antígenos CD/inmunología , Sitios de Unión , Línea Celular Tumoral , Chlorocebus aethiops , Retículo Endoplásmico/genética , Retículo Endoplásmico/inmunología , Retículo Endoplásmico/virología , Proteínas Ligadas a GPI/química , Proteínas Ligadas a GPI/genética , Proteínas Ligadas a GPI/inmunología , Regulación de la Expresión Génica , Aparato de Golgi/genética , Aparato de Golgi/inmunología , Aparato de Golgi/virología , Células HEK293 , Interacciones Huésped-Patógeno/inmunología , Humanos , Inmunidad Innata , Factores Reguladores del Interferón/clasificación , Factores Reguladores del Interferón/inmunología , Interferón Tipo I/inmunología , Simulación del Acoplamiento Molecular , Unión Proteica , Conformación Proteica en Hélice alfa , Conformación Proteica en Lámina beta , Dominios y Motivos de Interacción de Proteínas , SARS-CoV-2/inmunología , Transducción de Señal , Células Vero , Proteínas Virales/química , Proteínas Virales/inmunología , Internalización del Virus , Liberación del Virus/genética , Liberación del Virus/inmunología , Replicación Viral/genética , Replicación Viral/inmunologíaRESUMEN
A deficient interferon response to SARS-CoV-2 infection has been implicated as a determinant of severe COVID-19. To identify the molecular effectors that govern interferon control of SARS-CoV-2 infection, we conducted a large-scale gain-of-function analysis that evaluated the impact of human interferon stimulated genes (ISGs) on viral replication. A limited subset of ISGs were found to control viral infection, including endosomal factors that inhibited viral entry, nucleic acid binding proteins that suppressed viral RNA synthesis, and a highly enriched cluster of ER and Golgi-resident ISGs that inhibited viral translation and egress. These included the type II integral membrane protein BST2/tetherin, which was found to impede viral release, and is targeted for immune evasion by SARS-CoV-2 Orf7a protein. Overall, these data define the molecular basis of early innate immune control of viral infection, which will facilitate the understanding of host determinants that impact disease severity and offer potential therapeutic strategies for COVID-19.
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Two classes of antivirals targeting the viral neuraminidase (NA) and endonuclease are currently the only clinically useful drugs for the treatment of influenza. However, resistance to both antivirals has been observed in clinical isolates, and there was widespread resistance to oseltamivir (an NA inhibitor) among H1N1 viruses prior to 2009. This potential for resistance and lack of diversity for antiviral targets highlights the need for new influenza antivirals with a higher barrier to resistance. In this study, we identified an antiviral compound, M85, that targets host kinases, epidermal growth factor receptor (EGFR), and phosphoinositide 3 class II ß (PIK3C2ß) and is not susceptible to resistance by viral mutations. M85 blocks endocytosis of influenza viruses and inhibits a broad-spectrum of viruses with minimal cytotoxicity. In vitro, we found that combinations of M85 and oseltamivir have strong synergism. In the mouse model for influenza, treatment with the combination therapy was more protective against a lethal viral challenge than oseltamivir alone, indicating that development of M85 could lead to combination therapies for influenza. Finally, through this discovery of M85 and its antiviral mechanism, we present the first description of PIK3C2ß as a necessary host factor for influenza virus entry.
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Antivirales/farmacología , Inhibidores Enzimáticos/farmacología , Orthomyxoviridae/efectos de los fármacos , Oseltamivir/farmacología , Fosfatidilinositol 3-Quinasas/efectos de los fármacos , Internalización del Virus/efectos de los fármacos , Animales , Línea Celular , Chlorocebus aethiops , Fosfatidilinositol 3-Quinasas Clase II/efectos de los fármacos , Modelos Animales de Enfermedad , Combinación de Medicamentos , Evaluación Preclínica de Medicamentos , Farmacorresistencia Viral/efectos de los fármacos , Sinergismo Farmacológico , Receptores ErbB , Femenino , Humanos , Subtipo H1N1 del Virus de la Influenza A/efectos de los fármacos , Masculino , Ratones , Ratones Endogámicos BALB C , Células VeroRESUMEN
For the first time in nearly 20 years there is a new class of antiviral drug for influenza. The latest approved antiviral is baloxavir marboxil (trade name, Xofluza) which targets the endonuclease function of the viral PA polymerase subunit and prevents the transcription of viral mRNA. The most promising aspect of this new drug is its pharmacology which allows for effective treatment of influenza A or B virus infection with just a single dose. A clinical trial showed greater reductions in viral loads with baloxavir marboxil treatment compared with oseltamivir, although no difference in the time to alleviation of symptoms between these two drugs. With this new class of influenza drug comes exciting prospects for combination therapy with the neuraminidase inhibitors which may help to abate concerns about the development of resistance.
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Antivirales/farmacología , Gripe Humana/tratamiento farmacológico , Orthomyxoviridae/efectos de los fármacos , Oxazinas/farmacología , Piridinas/farmacología , Tiepinas/farmacología , Triazinas/farmacología , Animales , Ensayos Clínicos como Asunto , Dibenzotiepinas , Farmacorresistencia Viral , Humanos , Virus de la Influenza A/efectos de los fármacos , Virus de la Influenza B/efectos de los fármacos , Morfolinas , Infecciones por Orthomyxoviridae/tratamiento farmacológico , Piridonas , Carga Viral/efectos de los fármacosRESUMEN
Viruses utilize a number of host factors in order to carry out their replication cycles. Influenza A virus (IAV) and human respiratory syncytial virus (RSV) both infect the tissues of the respiratory tract, and as such we hypothesize that they might require similar host factors. Several published genome-wide screens have identified putative IAV host factors; however, there is significant discordance between their hits. In order to build on this work, we integrated a variety of "OMICS" data sources using two complementary network analyses, yielding 51 genes enriched for both IAV and RSV replication. We designed a targeted small interfering RNA (siRNA)-based assay to screen these genes against IAV under robust conditions and identified 13 genes supported by two IAV subtypes in both primary and transformed human lung cells. One of these hits, RNA binding motif 14 (RBM14), was validated as a required host factor and furthermore was shown to relocalize to the nucleolus upon IAV infection but not with other viruses. Additionally, the IAV NS1 protein is both necessary and sufficient for RBM14 relocalization, and relocalization also requires the double-stranded RNA (dsRNA) binding capacity of NS1. This work reports the discovery of a new host requirement for IAV replication and exposes a novel example of interplay between IAV NS1 and the host protein, RBM14.IMPORTANCE Influenza A virus (IAV) and respiratory syncytial virus (RSV) present major global disease burdens. There are high economic costs associated with morbidity as well as significant mortality rates, especially in developing countries, in children, and in the elderly. There are currently limited therapeutic options for these viruses, which underscores the need for novel research into virus biology that may lead to the discovery of new therapeutic approaches. This work extends existing research into host factors involved in virus replication and explores the interaction between IAV and one such host factor, RBM14. Further study to fully characterize this interaction may elucidate novel mechanisms used by the virus during its replication cycle and open new avenues for understanding virus biology.
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Nucléolo Celular/química , Interacciones Huésped-Patógeno , Virus de la Influenza A/fisiología , Péptidos y Proteínas de Señalización Intracelular/metabolismo , Proteínas no Estructurales Virales/metabolismo , Replicación Viral , Células Cultivadas , Humanos , Transporte de ProteínasRESUMEN
How transcription affects genome 3D organization is not well understood. We found that during influenza A (IAV) infection, rampant transcription rapidly reorganizes host cell chromatin interactions. These changes occur at the ends of highly transcribed genes, where global inhibition of transcription termination by IAV NS1 protein causes readthrough transcription for hundreds of kilobases. In these readthrough regions, elongating RNA polymerase II disrupts chromatin interactions by inducing cohesin displacement from CTCF sites, leading to locus decompaction. Readthrough transcription into heterochromatin regions switches them from the inert (B) to the permissive (A) chromatin compartment and enables transcription factor binding. Data from non-viral transcription stimuli show that transcription similarly affects cohesin-mediated chromatin contacts within gene bodies. Conversely, inhibition of transcription elongation allows cohesin to accumulate at previously transcribed intragenic CTCF sites and to mediate chromatin looping and compaction. Our data indicate that transcription elongation by RNA polymerase II remodels genome 3D architecture.
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Cromatina/metabolismo , Genoma Humano , Subtipo H5N1 del Virus de la Influenza A/metabolismo , Sitios de Unión , Factor de Unión a CCCTC/química , Factor de Unión a CCCTC/metabolismo , Proteínas Portadoras/antagonistas & inhibidores , Proteínas Portadoras/genética , Proteínas Portadoras/metabolismo , Proteínas de Ciclo Celular/metabolismo , Línea Celular , Cromatina/química , Proteínas Cromosómicas no Histona/metabolismo , Flavonoides/farmacología , Humanos , Interferón beta/farmacología , Macrófagos/citología , Macrófagos/metabolismo , Macrófagos/virología , Proteínas Nucleares/antagonistas & inhibidores , Proteínas Nucleares/genética , Proteínas Nucleares/metabolismo , Piperidinas/farmacología , Unión Proteica , Proteínas Proto-Oncogénicas/antagonistas & inhibidores , Proteínas Proto-Oncogénicas/genética , Proteínas Proto-Oncogénicas/metabolismo , Interferencia de ARN , ARN Polimerasa II/genética , ARN Polimerasa II/metabolismo , ARN Interferente Pequeño/metabolismo , Transcripción Genética/efectos de los fármacos , Proteínas no Estructurales Virales/genética , Proteínas no Estructurales Virales/metabolismo , CohesinasRESUMEN
A correction to this article has been published and is linked from the HTML and PDF versions of this paper. The error has been fixed in the paper.
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The human interferon (IFN)-induced MxA protein is a key antiviral host restriction factor exhibiting broad antiviral activity against many RNA viruses, including highly pathogenic avian influenza A viruses (IAV) of the H5N1 and H7N7 subtype. To date the mechanism for how MxA exerts its antiviral activity is unclear, however, additional cellular factors are believed to be essential for this activity. To identify MxA cofactors we performed a genome-wide siRNA-based screen in human airway epithelial cells (A549) constitutively expressing MxA using an H5N1 reporter virus. These data were complemented with a proteomic screen to identify MxA-interacting proteins. The combined data identified SMARCA2, the ATPase subunit of the BAF chromatin remodeling complex, as a crucial factor required for the antiviral activity of MxA against IAV. Intriguingly, our data demonstrate that although SMARCA2 is essential for expression of some IFN-stimulated genes (ISGs), and the establishment of an antiviral state, it is not required for expression of MxA, suggesting an indirect effect on MxA activity. Transcriptome analysis of SMARCA2-depleted A549-MxA cells identified a small set of SMARCA2-regulated factors required for activity of MxA, in particular IFITM2 and IGFBP3. These findings reveal that several virus-inducible factors work in concert to enable MxA restriction of IAV.
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Subtipo H5N1 del Virus de la Influenza A/crecimiento & desarrollo , Subtipo H7N7 del Virus de la Influenza A/crecimiento & desarrollo , Gripe Humana/virología , Proteínas de Resistencia a Mixovirus/metabolismo , Factores de Transcripción/metabolismo , Células A549 , Antivirales/farmacología , Perfilación de la Expresión Génica , Interacciones Huésped-Patógeno , Humanos , Subtipo H5N1 del Virus de la Influenza A/efectos de los fármacos , Subtipo H7N7 del Virus de la Influenza A/efectos de los fármacos , Gripe Humana/tratamiento farmacológico , Gripe Humana/metabolismo , Interferones/farmacología , Proteínas de Resistencia a Mixovirus/genética , Proteoma/análisis , Factores de Transcripción/genética , Replicación ViralRESUMEN
Paramyxovirus V proteins are known antagonists of the RIG-I-like receptor (RLR)-mediated interferon induction pathway, interacting with and inhibiting the RLR MDA5. We report interactions between the Nipah virus V protein and both RIG-I regulatory protein TRIM25 and RIG-I. We also observed interactions between these host proteins and the V proteins of measles virus, Sendai virus, and parainfluenza virus. These interactions are mediated by the conserved C-terminal domain of the V protein, which binds to the tandem caspase activation and recruitment domains (CARDs) of RIG-I (the region of TRIM25 ubiquitination) and to the SPRY domain of TRIM25, which mediates TRIM25 interaction with the RIG-I CARDs. Furthermore, we show that V interaction with TRIM25 and RIG-I prevents TRIM25-mediated ubiquitination of RIG-I and disrupts downstream RIG-I signaling to the mitochondrial antiviral signaling protein. This is a novel mechanism for innate immune inhibition by paramyxovirus V proteins, distinct from other known V protein functions such as MDA5 and STAT1 antagonism.IMPORTANCE The host RIG-I signaling pathway is a key early obstacle to paramyxovirus infection, as it results in rapid induction of an antiviral response. This study shows that paramyxovirus V proteins interact with and inhibit the activation of RIG-I, thereby interrupting the antiviral signaling pathway and facilitating virus replication.
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Proteína 58 DEAD Box/metabolismo , Infecciones por Paramyxoviridae/metabolismo , Paramyxoviridae/fisiología , Transducción de Señal , Factores de Transcripción/metabolismo , Proteínas de Motivos Tripartitos/metabolismo , Ubiquitina-Proteína Ligasas/metabolismo , Proteínas Virales/metabolismo , Replicación Viral , Células A549 , Animales , Proteína 58 DEAD Box/genética , Perros , Células HeLa , Humanos , Células de Riñón Canino Madin Darby , Complejos Multienzimáticos/genética , Complejos Multienzimáticos/metabolismo , Infecciones por Paramyxoviridae/genética , Receptores Inmunológicos , Factores de Transcripción/genética , Proteínas de Motivos Tripartitos/genética , Ubiquitina-Proteína Ligasas/genética , Ubiquitinación/genética , Proteínas Virales/genéticaRESUMEN
At every step of their replication cycle influenza viruses depend heavily on their host cells. The multifaceted interactions that occur between the virus and its host cell determine the outcome of the infection, including efficiency of progeny virus production, tropism, and pathogenicity. In order to understand viral disease and develop therapies for influenza it is therefore pertinent to study the intricate interplay between influenza viruses and their required host factors. Here, we review the current knowledge on host cell factors required by influenza virus at the different stages of the viral replication cycle. We also discuss the roles of host factors in zoonotic transmission of influenza viruses and their potential for developing novel antivirals.
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Interacciones Huésped-Patógeno/genética , Gripe Humana/genética , Gripe Humana/virología , Orthomyxoviridae/crecimiento & desarrollo , Replicación Viral , Humanos , Gripe Humana/tratamiento farmacológico , Orthomyxoviridae/patogenicidad , VirulenciaRESUMEN
S119 was a top hit from an ultrahigh throughput screen performed to identify novel inhibitors of influenza virus replication. It showed a potent antiviral effect (50% inhibitory concentration, IC50 = 20 nM) and no detectable cytotoxicity (50% cytotoxic concentration, CC50 > 500 µM) to yield a selectivity index greater than 25â¯000. Upon investigation, we found that S119 selected for resistant viruses carrying mutations in the viral nucleoprotein (NP). These resistance mutations highlight a likely S119 binding site overlapping with but not identical to that found for the compound nucleozin. Mechanism of action studies revealed that S119 affects both the oligomerization state and cellular localization of the NP protein which has an impact on viral transcription, replication, and protein expression. Through a hit-to-lead structure-activity relationship (SAR) study, we found an analog of S119, named S119-8, which had increased breadth of inhibition against influenza A and B viruses accompanied by only a small loss in potency. Finally, in vitro viral inhibition assays showed a synergistic relationship between S119-8 and oseltamivir when they were combined, indicating the potential for future drug cocktails.
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Antivirales/farmacología , Betainfluenzavirus/efectos de los fármacos , Virus de la Influenza A/efectos de los fármacos , Proteínas del Núcleo Viral/antagonistas & inhibidores , Animales , Línea Celular , Sinergismo Farmacológico , Regulación Viral de la Expresión Génica/efectos de los fármacos , Humanos , Virus de la Influenza A/fisiología , Betainfluenzavirus/fisiología , Pruebas de Sensibilidad Microbiana , Estructura Molecular , Oseltamivir/farmacología , Agregado de Proteínas/efectos de los fármacos , Unión Proteica , Internalización del Virus/efectos de los fármacos , Replicación Viral/efectos de los fármacosRESUMEN
Options for influenza therapy are currently limited to one class of drug, the neuraminidase inhibitors. Amidst concerns about drug resistance, much effort has been placed on the discovery of new drugs with distinct targets and mechanisms of action, with great success. There are now several candidates in late stage development which include small molecules targeting the three subunits of the viral polymerase complex and monoclonal antibodies targeting the hemagglutinin, as well as host-directed therapies. The availability of drugs with diverse mechanisms now opens the door to exploring combination therapies for influenza, and the range of administration routes presents more opportunities for treating hospitalized patients.
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Antivirales/uso terapéutico , Descubrimiento de Drogas , Gripe Humana/tratamiento farmacológico , Antivirales/clasificación , HumanosRESUMEN
Ebola virus (EBOV), a member of the family Filoviridae, is a nonsegmented negative-sense RNA virus that causes severe, often lethal, disease in humans. EBOV RNA synthesis is carried out by a complex that includes several viral proteins. The function of this machinery is essential for viral gene expression and viral replication and is therefore a potential target for antivirals. We developed and optimized a high-throughput screening (HTS) assay based on an EBOV minigenome assay, which assesses the function of the polymerase complex. The assay is robust in 384-well format and displays a large signal to background ratio and high Z-factor values. We performed a pilot screen of 2080 bioactive compounds, identifying 31 hits (1.5% of the library) with >70% inhibition of EBOV minigenome activity. We further identified eight compounds with 50% inhibitory concentrations below their 50% cytotoxic concentrations, five of which had selectivity index (SI) values >10, suggesting specificity against the EBOV polymerase complex. These included an inhibitor of inosine monophosphate dehydrogenase, a target known to modulate the EBOV replication complex. They also included novel classes of inhibitors, including inhibitors of protein synthesis and hypoxia inducible factor-1. Five compounds were tested for their ability to inhibit replication of a recombinant EBOV that expresses GFP (EBOV-GFP), and four inhibited EBOV-GFP growth at sub-cytotoxic concentrations. These data demonstrate the utility of the HTS minigenome assay for drug discovery and suggest potential directions for antifiloviral drug development.