JAK3 and PI3K mediate bovine Interferon-tau stimulated gene expression in the blood neutrophils

Interferon tau, a 23 kDa trophoblast derived protein diffuses out from the uterus into the circulation and leads to the expression of IFNτ stimulated genes viz. ISG15 and OAS1 in blood neutrophils. The IFNτ pathway is species as well as tissue specific. To unsnarl the IFNτ downstream signaling pathway, the blood neutrophils were incubated simultaneously with 10 ng/ml of recombinant bovine interferon tau and the inhibitors of JAK2 (AG490), JAK3 (CP690550), p38 (SB202190), PI3K/Akt (LY294002), and MAPK/Erk (U0126) at specific doses for 4-hr duration. The IFNτ pathway was determined through real-time gene expression of ISG15 and OAS1; immunocytochemistry of ISG15; and Western blotting of ISG15, OAS1, pJAK3 and PI3K. The ISG15 and OAS1 expression decreased significantly (p < 0.001) in the presence of pJAK3 and PI3K inhibitors as compared to a positive control where only interferon tau was used. Immunocytochemistry revealed an attenuated ISG15 response while stimulating blood neutrophils with pJAK3 inhibitor (CP690550) and PI3K inhibitor (LY294002). Similarly, Western blot analysis of neutrophil protein fraction showed weak signals of ISG15, OAS1, pJAK3 and PI3K in the presence of pJAK3 and PI3K inhibitors. The expression profile, immunocytochemistry and western blot analysis revealed a JAK3 and PI3K mediated interferon-tau stimulated gene expression in blood neutrophils.