Porcine epidemic diarrhea virus (PEDV), the causative agent of PED, belongs to the genus Alphacoronavirus in the family Coronaviridae.
Reactive oxygen species (ROS), endoplasmic reticulum (ER) stress, and autophagy play crucial roles in regulating a variety of cellular processes during
viral infection. However, the precise role of autophagy in PEDV-infected Vero cells remains largely elusive. To elucidate how PEDV
infection induces autophagy, this study ascertained whether ER stress was present in PEDV-infected Vero cells. The results showed PEDV
infection significantly increased the expression of
GRP78 and LC3Ⅱ. Treatment with the ER stress inhibitor
4-phenylbutyrate (4-PBA) could significantly inhibit PEDV-induced autophagy.
Antioxidants, such as
N-acetylcysteine (NAC), could significantly inhibit PEDV-induced ER stress and autophagy, indicating that ROS act as an upstream regulator of ER stress-mediated autophagy. Further research found that activation of ER stress triggered the unfolded protein response (UPR) through PERK, IRE1, and ATF6 pathways during PEDV
infection. However, treatment with the PERK inhibitor
GSK2606414, IRE1 inhibitor
STF-083010 but not ATF6 inhibitor
AEBSF reversed PEDV-induced autophagy. Taken together, the results of this study showed that accumulated ROS played an essential role in regulating ER stress-mediated autophagy during PEDV
infection. We also found that PERK and IER1 pathways of UPR signalling were involved in PEDV-induced autophagy. Furthermore, PEDV induced autophagy to promote viral replication via PERK and IER1 pathways in Vero cells. These results provide the mechanism of PEDV-induced ROS-dependent ER stress-mediated autophagy in Vero cells through activating PERK and IRE1 pathways.