Suppression of a JAK-STAT pathway target gene Ftz-F1H enhances the resistance of shrimp to Vibrio parahaemolyticus

Abstract

Bacterial diseases, especially those caused by Vibrio infection, are major constraints to shrimp aquaculture. The fushi tarazu (FTZ) transcription factor (Ftz-F1) is an orphan nuclear receptor now known to be essentially involved in embryonic development, but its role in immunity is still unknown. In the current study, a Ftz-F1 homologue (Ftz-F1H) was identified from Pacific white shrimp Litopenaeus vannamei and functionally studied in the context of antibacterial response. Ftz-F1H was a target gene of the JAK-STAT pathway and its product was mainly localized in the nucleus. The expression of Ftz-F1H was significantly up-regulated upon bacterial stimulation, indicating its involvement in antibacterial response. In Ftz-F1H-silenced shrimp, expression of a set of immune effector genes and the phagocytic activity of hemocytes were increased. Moreover, the mortality rate of Vibrio parahaemolyticus infected shrimp as well as the bacterial load in tissues was significantly decreased after silencing of Ftz-F1H. These suggested that Ftz-F1H functioned as an inhibitor of antibacterial response in shrimp. To our knowledge, it is the first report on the immune function of Ftz-F1 family in invertebrates. The shrimp Ftz-F1H gene could be potentially used as a therapeutic target for improving immune defense against bacterial infection.