4,4-Diaponeurosporene regulated lactoferrin expression in neutrophils by IL-27 secreted dendritic cells

Sow colostrum is rich in lactoferrin (LF), which can be orally administered to protect piglets from porcine epidemic diarrhea virus (PEDV) infection, thereby reducing piglet mortality. Previous study has shown that sows fed with recombinant B. subtilis expressing 4,4-diaponeurosporene (B.S-Dia) have significantly higher LF levels in their colostrum compared to sows fed with B. subtilis. This suggests that 4,4-diaponeurosporene (DNP) produced by B.S-Dia may influence LF content in sow colostrum. In this study, we first extracted DNP expressed by the recombinant probiotic using acetone-hexane extraction. Flow cytometry, RT-qPCR, and ELISA analyses demonstrated that DNP promoted dendritic cell (DCs) maturation and increased the expression of IL-1β and IL-27. We then established a method for isolating neutrophils from sow colostrum and set up a co-culture system of neutrophils and DCs to investigate factors regulating LF secretion. The results indicated that DCs secretions enhanced LF expression in neutrophils. Finally, the application of IL-27 inhibitors confirmed that IL-27 produced by DCs upregulates LF secretion in neutrophils. These findings elucidate the mechanism by which DNP promotes LF production in colostrum and provide a theoretical foundation for using B.S-Dia to prevent and control PEDV infection in piglets.