RESUMO
Interleukin (IL) 27 is a member of the IL-12 family and is a heterodimeric cytokine composed of IL-27A and Epstein-Barr virus-induced 3 (EBI3). It plays an important role in regulating inflammation and cancer progression. IL-27A not only functions by dimerizing with EBI3 but also acts alone. Here, we report that IL-27A and EBI3 suppress spring viremia of carp virus (SVCV) replication in zebrafish. Expression analysis reveals that il-27a and ebi3 were significantly upregulated in the ZF4 cells by SVCV and poly(I:C), and in the zebrafish caudal fin (ZFIN) cells overexpressed with SVCV genes. Interestingly, il-27a and ebi3 were not modulated by IFNφ1, indicating that they are not IFN stimulated genes (ISGs). Furthermore, overexpression of IL-27A and EBI3 alone inhibited SVCV replication in the EPC cells, but less potent than co-expression of IL-27A and EBI3. Intriguingly, IL-27A could not induce the expression of irf3, ifn, isg15 and mx1. Taken together, our results demonstrate that IL-27A and EBI3 activate innate antiviral response in an IFN independent manner in zebrafish.
Assuntos
Doenças dos Peixes , Interleucina-27 , Infecções por Rhabdoviridae , Rhabdoviridae , Peixe-Zebra , Animais , Infecções por Vírus Epstein-Barr , Proteínas de Peixes/genética , Proteínas de Peixes/metabolismo , Herpesvirus Humano 4/metabolismo , Interleucina-27/genética , Interleucinas/genética , Rhabdoviridae/fisiologia , Infecções por Rhabdoviridae/veterinária , Viremia , Replicação Viral , Peixe-Zebra/genética , Peixe-Zebra/metabolismoRESUMO
IFN regulatory factor (IRF) 2 belongs to the IRF1 subfamily, and its functions are not yet fully understood. In this study, we showed that IRF2a was a negative regulator of the interferon (IFN) response induced by spring viremia of carp virus (SVCV). Irf2a-/- knockout zebrafish were less susceptible to SVCV than wild-type fish. Transcriptomic analysis reveals that differentially expressed genes (DEGs) in the irf2a-/- and irf2a+/+ cells derived caudal fins were mainly involved in cytokine-cytokine receptor interaction, mitogen-activated protein kinase (MAPK) signaling pathway, and transforming growth factor-beta (TGF-beta) signaling pathway. Interestingly, the basal expression levels of interferon stimulating genes (ISGs), including pkz, mx, apol, and stat1 were higher in the irf2a-/- cells than irf2a+/+ cells, suggesting that they may contribute to the increased viral resistance of the irf2a-/- cells. Overexpression of IRF2a inhibited the activation of ifnφ1 and ifnφ3 induced by SVCV and poly(I:C) in the epithelioma papulosum cyprini (EPC) cells. Further, it was found that SVCV phosphoprotein (SVCV-P) could interact with IRF2a to promote IRF2a nuclear translocation and protein stability via suppressing K48-linked ubiquitination of IRF2a. Both IRF2a and SVCV-P not only destabilized STAT1a but reduced its translocation into the nucleus. Our work demonstrates that IRF2a cooperates with SVCV-P to suppress host antiviral response against viral infection in zebrafish. IMPORTANCE Interferon regulatory factors (IRFs) are central in the regulation of interferon-mediated antiviral immunity. Here, we reported that IRF2a suppressed interferon response and promoted virus replication in zebrafish. The suppressive effects were enhanced by the phosphoprotein of the spring viremia of carp virus (SVCV) via inhibition of K48-linked ubiquitination of IRF2a. IRF2a and SVCV phosphoprotein cooperated to degrade STAT1 and block its nuclear translocation. Our work demonstrated that IRFs and STATs were targeted by the virus through posttranslational modifications to repress interferon-mediated antiviral response in lower vertebrates.
Assuntos
Doenças dos Peixes , Fator Regulador 2 de Interferon , Fosfoproteínas , Infecções por Rhabdoviridae , Rhabdoviridae , Animais , Doenças dos Peixes/virologia , Interferons/imunologia , Fosfoproteínas/metabolismo , Rhabdoviridae/fisiologia , Infecções por Rhabdoviridae/imunologia , Infecções por Rhabdoviridae/veterinária , Viremia , Peixe-Zebra/virologia , Fator Regulador 2 de Interferon/metabolismo , Técnicas de Inativação de Genes , Processamento de Proteína Pós-Traducional , Fator de Transcrição STAT1 , Replicação ViralRESUMO
PLAAT1 is a member of the PLAAT protein family and plays important roles in tumor suppression, transglutaminase activation and peroxisomal biogenesis. Recently, PLAAT1 has been shown to promote degradation of p53 protein and cellular organelles such as mitochondria, endoplasmic reticulum and lysosome. In this study, we show that PLAAT1 inhibits the production of type I interferon and promotes virus replication in zebrafish. Overexpression of Plaat1 in zebrafish cells suppresses antiviral responses and promotes virus replication. Mechanistically, PLAAT1 interacts with IRF3 and IRF7 to initiate degradation of IRF3 and IRF7, which can be attenuated by 3-methyladenine, an inhibitor of autophagosome. Our study provides novel insights into the functions of PLAAT1 in host immune response to viral infection.
Assuntos
Interferon Tipo I , Animais , Antivirais , Fatores Reguladores de Interferon/metabolismo , Interferon Tipo I/metabolismo , Transglutaminases/metabolismo , Proteína Supressora de Tumor p53 , Peixe-Zebra/metabolismo , Proteínas de Peixe-Zebra/genética , Proteínas de Peixe-Zebra/metabolismoRESUMO
PLAAT1 belongs to the PLAAT family and plays regulatory roles in cell growth, tumor suppression and phospholipid metabolism. However, whether PLAAT1 is involved in p53 mediated signaling has not been investigated. Here, we report that PLAAT1 promotes degradation of p53 in zebrafish. We found that the plaat1 gene was constitutively expressed in tissues including liver, kidney, spleen, intestine, eye and brain, with relative higher expression levels detected in the brain and eye. Overexpression of plaat1 led to inhibition of p53 and tnfα mRNA expression. Furthermore, it was shown that PLAAT1 interacted with p53 to facilitate p53 degradation via autophagy-lysosome dependent pathway. Our work indicates that PLAAT1 is involved in the interplay between p53 mediated cellular responses and autophagy.