Autophagy Benefits the Replication of Egg Drop Syndrome Virus in Duck Embryo Fibroblasts

Abstract

Egg drop syndrome virus (EDSV) is an economically important pathogen with a broad host range, and it causes disease that leads to markedly decreased egg production. Although EDSV is known to induce apoptosis in duck embryo fibroblasts (DEFs), the interaction between EDSV and its host needs to be further researched. Here, we provide the first evidence that EDSV infection triggers autophagy in DEFs through increases in autophagosome-like double-membrane vesicles, the conversion of LC3-I to LC3-II, and LC3 colocalization with viral hexon proteins. Conversely, P62/SQSTM1 degradation, LC3-II turnover, and colocalization of LAMP and LC3 confirmed that EDSV infection triggers complete autophagy. Furthermore, we demonstrated that inhibition of autophagy by chloroquine (CQ) and 3-methyladenine (3MA) or RNA interference targeting ATG-7 decreased the yield of EDSV progeny. In contrast, induction of autophagy by rapamycin increased the EDSV progeny yield. In addition, we preliminarily demonstrated that the class I phosphoinositide 3-kinase (PI3K)/Akt/mTOR pathway contributes to autophagic induction following EDSV infection. Altogether, these finding lead us to conclude that EDSV infection induces autophagy, which benefits its own replication in host cells. These findings provide novel insights into EDSV–host interactions.

Glutamine Deficiency Promotes PCV2 Infection through Induction of Autophagy via Activation of ROS-Mediated JAK2/STAT3 Signaling Pathway

“…Autophagy is an intracellular bulk degradation pathway that is induced by diverse intracellular and extracellular stimuli. − In many previous studies, autophagy was regarded as a pro-viral defense mechanism in the pathogenesis of many viruses, , while several viruses have been shown to exploit the autophagic responses in favor of their infection. − Recently, our study in vitro has focused on the role of autophagy in promoting PCV2 infection, , and a few studies have been carried out in an in vivo model. Given that some virus infection in vivo has been illustrated recently to be affected by autophagy , and Gln deficiency could induce autophagy, we tested the hypothesis that autophagy induction might play an important role in PCV2 infection promoted by Gln deficiency in vivo and in vitro .…”

The Multi-Faceted Role of Autophagy During Animal Virus Infection

“…To date, only one report has verified the interaction between EDSV and autophagy. Wang et al (2018) reported that EDSV infection in duck embryo fibroblasts (DEFs) cells activates complete autophagy through the class I PI3K/Akt/mTOR pathway and exploits autophagy to enhance its replication.…”