Wnt11 positively regulates immune defense against Vibrio parahaemolyticus but promotes white spot syndrome virus infection in Litopenaeus vannamei

Vibrio parahaemolyticus and white spot syndrome virus (WSSV) are major threats for shrimp aquaculture. The Wnt family genes are well known to be involved in development and growth. In this study, the role of the Wnt11 gene from Pacific white shrimp Litopenaeus vannamei (LvWnt11) was investigated in the context of immune responses against V. parahaemolyticus and WSSV infection. We demonstrated that expression of LvWnt11 was regulated by Relish, Dorsal and STAT signaling pathways and changed after infection with various pathogens. Silencing of LvWnt11 in vivo significantly attenuated the immune defense against V. parahaemolyticus infection but enhanced that against WSSV infection. Although not affecting hemocyte phagocytosis, LvWnt11 regulated expression of immune related transcription factors Relish, Dorsal and STAT and a series of immune function proteins. Besides regulating promoters of target genes, LvWnt11 cooperated with Relish and Dorsal to improve their transcription regulatory activities. Moreover, LvWnt11 activated immediate early gene ie1 of WSSV, which could contribute to its promoting effect on WSSV infection. Therefore, the current study demonstrated that LvWnt11 played opposite roles in V. parahaemolyticus and WSSV infection, which may help to reveal the immune mechanisms in crustaceans and provide support for the prevention of diseases in cultured shrimp.