RESUMEN
Elucidating virus-cell interactions is fundamental to understanding viral replication and identifying targets for therapeutic control of viral infection. The extracellular signal-regulated kinase (ERK) pathway has been shown to regulate pathogenesis during many viral infections, but its role during coronavirus infection is undetermined. Infectious bronchitis virus is the representative strain of Gammacoronavirus, which causes acute and highly contagious diseases in the poultry farm. In this study, we investigated the role of ERK1/2 signaling pathway in IBV infection. We found that IBV infection activated ERK1/2 signaling and the up-regulation of phosphatase DUSP6 formed a negative regulation loop. Pharmacological inhibition of MEK1/2-ERK1/2 signaling suppressed the expression of DUSP6, promoted cell death, and restricted virus replication. In contrast, suppression of DUSP6 by chemical inhibitor or siRNA increased the phosphorylation of ERK1/2, protected cells from apoptosis, and facilitated IBV replication. Overexpression of DUSP6 decreased the level of phospho-ERK1/2, promoted apoptosis, while dominant negative mutant DUSP6-DN lost the regulation function on ERK1/2 signaling and apoptosis. In conclusion, these data suggest that MEK-ERK1/2 signaling pathway facilitates IBV infection, probably by promoting cell survival; meanwhile, induction of DUSP6 forms a negative regulation loop to restrict ERK1/2 signaling, correlated with increased apoptosis and reduced viral load. Consequently, components of the ERK pathway, such as MEK1/2 and DUSP6, represent excellent targets for the development of antiviral drugs.
Asunto(s)
Apoptosis/fisiología , Fosfatasas de Especificidad Dual/metabolismo , Quinasas MAP Reguladas por Señal Extracelular/metabolismo , Virus de la Bronquitis Infecciosa/fisiología , Fosfatasas de la Proteína Quinasa Activada por Mitógenos/metabolismo , Animales , Butadienos/farmacología , Línea Celular , Pollos , Chlorocebus aethiops , Fosfatasas de Especificidad Dual/antagonistas & inhibidores , Fosfatasas de Especificidad Dual/genética , Quinasas MAP Reguladas por Señal Extracelular/genética , Fosfatasas de la Proteína Quinasa Activada por Mitógenos/antagonistas & inhibidores , Fosfatasas de la Proteína Quinasa Activada por Mitógenos/genética , Nitrilos/farmacología , Regulación hacia Arriba , Replicación ViralRESUMEN
Inflammatory responses are important aspects of the innate immune system during virus infection. We found that Newcastle disease virus can induce inflammasome activation in the human macrophage-like cell line THP-1. Viral replication was required for inflammasome activation, and small hairpin RNA knockdown experiments indicated that IL-1ß secretion was mediated by the NLRP3 inflammasome. We also verified the results in LPS-primed bone marrow-derived macrophages (BMDMs) from NLRP3-deficient and wild type mice. NDV is considered to be a promising oncolytic virus. Stimulating the immune system has been proposed as a key mechanism of oncolytic specificity, and the inflammasome appears to be an important mechanism by which NDV is controlled. Knockdown of inflammasome components or chemical inhibition of caspase-1 activity shows that cell survival was augmented and benefited NDV replication. This study shows that NLRP3 inflammasome activation is an innate cellular response to NDV infection and offers insights into the oncolytic specificity of NDV.
