Death Receptor DR5 as a Proviral Factor for Viral Entry and Replication of Coronavirus PEDV

Porcine epidemic diarrhea virus (PEDV), a member of Coronaviridae, causes high mortality in newborn piglets, and has caused significant economic losses in the pig industry. PEDV infection can induce apoptosis, both caspase-dependent and caspase-independent, but the details of apoptosis remain clarified. This study investigated the effect of death receptor DR5 on PEDV infection and its relationship with PEDV-induced apoptosis. We found that DR5 knockdown reduced viral mRNA and protein levels of PEDV, and the viral titer decreased from 10(4.5) TCID(50) to 10(3.4) TCID(50) at 12 hpi. Overexpression of DR5 significantly increased the viral titer. Further studies showed that DR5 facilitates viral replication by regulating caspase-8-dependent apoptosis, and the knockdown of DR5 significantly reduced PEDV-induced apoptosis. Interestingly, we detected a biphasic upregulation expression of DR5 in both Vero cells and piglets in response to PEDV infection. We found that DR5 also facilitates viral entry of PEDV, especially, incubation with DR5 antibody can reduce the PEDV binding to Vero cells. Our study improves the understanding of the mechanism by which PEDV induces apoptosis and provides new insights into the biological function of DR5 in PEDV infection.