SERPINB1 promotes porcine deltacoronavirus replication by targeting the viral accessory protein NS7a.

Porcine deltacoronavirus (PDCoV) is an emerging porcine enteric coronavirus in China, with the risk of cross-species transmission and zoonotic infection. SERPINB1, serine protease inhibitor, is a potential therapeutic target. It is unclear whether its role in PDCoV replication. Our study found that PDCoV infection upregulates the expression level of SERPINB1, suggesting a potential role for SERPINB1 in the viral life cycle. Further investigation revealed that SERPINB1 is an essential factor for viral replication, and its RCL domain is the key region for its viral-promoting activity. Moreover, SERPINB1 interacts with accessory protein NS7a of PDCoV. Understanding the mechanism by which SERPINB1 targets viral encoded proteins to promote PDCoV replication can enrich the pathogenesis and immune mechanism of PDCoV, and provide new targets and important theoretical basis for the development of antiviral drugs.