Porcine epidemic diarrhea virus (PEDV) causes acute and devastating enteric disease in suckling piglets and results in huge economic losses in the pig industry worldwide. To establish productive
infection, viruses must first circumvent the host innate immune response. In this study, we found that PEDV
infection stimulated
epidermal growth factor receptor (EGFR) activation, which has been linked to not only anticancer
therapeutics, but also
antiviral signaling. Therefore, we determined whether EGFR activation affected PEDV
infection by using an activator or overexpression assay. The data showed that EGFR activation enhanced virus replication in both cases. We also found that specific inhibition of EGFR by either inhibitors or
small interfering RNA (
siRNA) led to a decrease in virus yields. Further analysis revealed that inhibition of EGFR produced augmentation of
type I interferon genes. We next observed that the EGFR downstream cascade STAT3 was also activated upon PEDV
infection. Similar to the case of EGFR, specific inhibition of STAT3 by either inhibitor or
siRNA increased the
antiviral activity of
interferon and resulted in decreased PEDV
RNA levels, and vice versa. The data on STAT3 depletion in combination with EGFR activation suggest that the attenuation of
antiviral activity by EGFR activation requires activation of the STAT3 signaling pathway. Taken together, these data demonstrate that PEDV-induced EGFR activation serves as a negative regulator of the
type I interferon response and provides a novel therapeutic target for
virus infection.IMPORTANCE EGFR is a transmembrane
tyrosine receptor that mediates various cellular events, as well as several types of human
cancers. In this study, we investigated for the first time the role of EGFR in PEDV
infection. We observed that PEDV
infection induced EGFR activation. The role of EGFR activation is to impair the
antiviral activity of
type I interferon, which requires the involvement of the EGFR downstream signaling cascade STAT3. Our findings reveal a new mechanism evolved by PEDV to circumvent the host
antiviral response, which might serve as a therapeutic target against
virus infection.