The antiviral protein viperin interacts with the viral N protein to inhibit proliferation of porcine epidemic diarrhea virus

In the early stage of virus infection, the pattern recognition receptor (PRR) signaling pathway of the host cell is activated to induce interferon production, activating interferon-stimulated genes (ISGs) that encode antiviral proteins that exert antiviral effects. Viperin is one of the innate antiviral proteins that exert broad-spectrum antiviral effects by various mechanisms. Porcine epidemic diarrhea virus (PEDV) is a coronavirus that causes huge losses to the pig industry. Research on early antiviral responses in the gastrointestinal tract is essential for developing strategies to prevent the spread of PEDV. In this study, we investigated the mechanisms of viperin in PEDV-infected IPEJ-C2 cells. Increased expression of interferon and viperin and decreased replication of PEDV with a clear reduction in the viral load were observed in PEDV-infected IPEC-J2 cells. Amino acids 1-50 of porcine viperin contain an endoplasmic reticulum signal sequence that allows viperin to be anchored to the endoplasmic reticulum and are necessary for its function in inhibiting PEDV proliferation. The interaction of the viperin S-adenosylmethionine domain with the N protein of PEDV was confirmed via confocal laser scanning microscopy and co-immunoprecipitation. This interaction might interfere with viral replication or assembly to reduce virus proliferation. Our results highlight a potential mechanism whereby viperin is able to inhibit PEDV replication and play an antiviral role in innate immunity.