RESUMO
IMPORTANCE: One of the fundamental features that make viruses intracellular parasites is the necessity to use cellular translational machinery. Hence, this is a crucial checkpoint for controlling infections. Here, we show that dengue and Zika viruses, responsible for nearly 400 million infections every year worldwide, explore such control for optimal replication. Using immunocompetent cells, we demonstrate that arrest of protein translations happens after sensing of dsRNA and that the information required to avoid this blocking is contained in viral 5'-UTR. Our work, therefore, suggests that the non-canonical translation described for these viruses is engaged when the intracellular stress response is activated.
Assuntos
Vírus da Dengue , Estresse Fisiológico , Replicação Viral , Zika virus , eIF-2 Quinase , Animais , Humanos , Células A549 , Chlorocebus aethiops , Dengue/imunologia , Dengue/virologia , Vírus da Dengue/fisiologia , eIF-2 Quinase/genética , eIF-2 Quinase/metabolismo , Fator de Iniciação 2 em Eucariotos/metabolismo , Deleção de Genes , Biossíntese de Proteínas/genética , Biossíntese de Proteínas/imunologia , Estresse Fisiológico/genética , Estresse Fisiológico/imunologia , Células Vero , Replicação Viral/genética , Replicação Viral/imunologia , Zika virus/fisiologia , Infecção por Zika virus/imunologia , Infecção por Zika virus/virologia , RNA de Cadeia Dupla/metabolismoRESUMO
IFN-stimulated gene 15 (ISG15) deficiency in humans leads to severe IFNopathies and mycobacterial disease, the latter being previously attributed to its extracellular cytokine-like activity. In this study, we demonstrate a novel role for secreted ISG15 as an IL-10 inducer, unique to primary human monocytes. A balanced ISG15-induced monocyte/IL-10 versus lymphoid/IFN-γ expression, correlating with p38 MAPK and PI3K signaling, was found using targeted in vitro and ex vivo systems analysis of human transcriptomic datasets. The specificity and MAPK/PI3K-dependence of ISG15-induced monocyte IL-10 production was confirmed in vitro using CRISPR/Cas9 knockout and pharmacological inhibitors. Moreover, this ISG15/IL-10 axis was amplified in leprosy but disrupted in human active tuberculosis (TB) patients. Importantly, ISG15 strongly correlated with inflammation and disease severity during active TB, suggesting its potential use as a biomarker, awaiting clinical validation. In conclusion, this study identifies a novel anti-inflammatory ISG15/IL-10 myeloid axis that is disrupted in active TB.
Assuntos
Citocinas/imunologia , Interleucina-10/imunologia , Leucócitos Mononucleares/imunologia , Tuberculose/imunologia , Ubiquitinas/imunologia , HumanosRESUMO
Targeting regions of proteins that show a high degree of structural conservation has been proposed as a method of developing immunotherapies and vaccines that may bypass the wide genetic variability of RNA viruses. Despite several attempts, a vaccine that protects evenly against the four circulating Dengue virus (DV) serotypes remains elusive. To find critical conserved amino acids in dengue viruses, 120 complete genomes of each serotype were selected at random and used to calculate conservation scores for nucleotide and amino acid sequences. The identified peptide sequences were analysed for their structural conservation and localisation using crystallographic data. The longest, surface exposed, highly conserved peptide of Envelope protein was found to correspond to amino acid residues 250 to 270. Mutation of this peptide in DV1 was lethal, since no replication of the mutant virus was detected in human cells. Antibodies against this peptide were detected in DV naturally infected patients indicating its potential antigenicity. Hence, this study has identified a highly conserved, critical peptide in DV that is a target of antibodies in infected humans.