RESUMO
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.
Assuntos
Antígenos CD/genética , Interações Hospedeiro-Patógeno/genética , Fatores Reguladores de Interferon/genética , Interferon Tipo I/genética , SARS-CoV-2/genética , Proteínas Virais/genética , Animais , Antígenos CD/química , Antígenos CD/imunologia , Sítios de Ligação , Linhagem Celular Tumoral , Chlorocebus aethiops , Retículo Endoplasmático/genética , Retículo Endoplasmático/imunologia , Retículo Endoplasmático/virologia , Proteínas Ligadas por GPI/química , Proteínas Ligadas por GPI/genética , Proteínas Ligadas por GPI/imunologia , Regulação da Expressão Gênica , Complexo de Golgi/genética , Complexo de Golgi/imunologia , Complexo de Golgi/virologia , Células HEK293 , Interações Hospedeiro-Patógeno/imunologia , Humanos , Imunidade Inata , Fatores Reguladores de Interferon/classificação , Fatores Reguladores de Interferon/imunologia , Interferon Tipo I/imunologia , Simulação de Acoplamento Molecular , Ligação Proteica , Conformação Proteica em alfa-Hélice , Conformação Proteica em Folha beta , Domínios e Motivos de Interação entre Proteínas , SARS-CoV-2/imunologia , Transdução de Sinais , Células Vero , Proteínas Virais/química , Proteínas Virais/imunologia , Internalização do Vírus , Liberação de Vírus/genética , Liberação de Vírus/imunologia , Replicação Viral/genética , Replicação Viral/imunologiaRESUMO
In recent years genome-wide RNAi screens have revealed hundreds of cellular factors required for influenza virus infections in human cells. The long-term goal is to establish some of them as drug targets for the development of the next generation of antivirals against influenza. We found that several members of the polo-like kinases (PLK), a family of serine/threonine kinases with well-known roles in cell cycle regulation, were identified as hits in four different RNAi screens and we therefore studied their potential as drug target for influenza. We show that knockdown of PLK1, PLK3, and PLK4, as well as inhibition of PLK kinase activity by four different compounds, leads to reduced influenza virus replication, and we map the requirement of PLK activity to early stages of the viral replication cycle. We also tested the impact of the PLK inhibitor BI2536 on influenza virus replication in a human lung tissue culture model and observed strong inhibition of virus replication with no measurable toxicity. This study establishes the PLKs as potential drug targets for influenza and contributes to a more detailed understanding of the intricate interactions between influenza viruses and their host cells.
Assuntos
Vírus da Influenza A/efeitos dos fármacos , Proteínas Serina-Treonina Quinases/antagonistas & inibidores , Proteínas Serina-Treonina Quinases/metabolismo , Replicação Viral/efeitos dos fármacos , Células A549 , Animais , Antimitóticos/farmacologia , Proteínas de Ciclo Celular/antagonistas & inibidores , Proteínas de Ciclo Celular/genética , Proteínas de Ciclo Celular/metabolismo , Cães , Glicina/análogos & derivados , Glicina/farmacologia , Células HEK293 , Humanos , Vírus da Influenza A/fisiologia , Influenza Humana/prevenção & controle , Influenza Humana/virologia , Células Madin Darby de Rim Canino , Inibidores de Proteínas Quinases/farmacologia , Proteínas Serina-Treonina Quinases/genética , Proteínas Proto-Oncogênicas/antagonistas & inibidores , Proteínas Proto-Oncogênicas/genética , Proteínas Proto-Oncogênicas/metabolismo , Pteridinas/farmacologia , Interferência de RNA , Sulfonas/farmacologia , Proteínas Supressoras de Tumor , Quinase 1 Polo-LikeRESUMO
Retinoic acid-inducible gene I (RIG-I) receptor recognizes 5'-triphosphorylated RNA and triggers a signalling cascade that results in the induction of type-I interferon (IFN)-dependent responses. Its precise regulation represents a pivotal balance between antiviral defences and autoimmunity. To elucidate the cellular cofactors that regulate RIG-I signalling, we performed two global RNA interference analyses to identify both positive and negative regulatory nodes operating on the signalling pathway during virus infection. These factors were integrated with experimentally and computationally derived interactome data to build a RIG-I protein interaction network. Our analysis revealed diverse cellular processes, including the unfolded protein response, Wnt signalling and RNA metabolism, as critical cellular components governing innate responses to non-self RNA species. Importantly, we identified K-Homology Splicing Regulatory Protein (KHSRP) as a negative regulator of this pathway. We find that KHSRP associates with the regulatory domain of RIG-I to maintain the receptor in an inactive state and attenuate its sensing of viral RNA (vRNA). Consistent with increased RIG-I antiviral signalling in the absence of KHSRP, viral replication is reduced when KHSRP expression is knocked down both in vitro and in vivo. Taken together, these data indicate that KHSRP functions as a checkpoint regulator of the innate immune response to pathogen challenge.