Deubiquitinase cylindromatosis (CYLD) regulates antibacterial immunity and apoptosis in Chinese mitten crab (Eriocheir sinensis).

Ubiquitination and deubiquitination of target proteins is an important mechanism for cells to rapidly respond to changes in the external environment. The deubiquitinase, cylindromatosis (CYLD), is a tumor suppressor protein. CYLD from Drosophila melanogaster participates in the antimicrobial immune response. In vertebrates, CYLD also regulates bacterial-induced apoptosis. However, whether CYLD can regulate the bacterial-induced innate immune response in crustaceans is unknown. In the present study, we reported the identification and cloning of CYLD in Chinese mitten crab, Eriocheir sinensis. Quantitative real-time reverse transcription polymerase chain reaction analysis showed that EsCYLD was widely expressed in all the examined tissues and was upregulated in the hemolymph after Vibrio parahaemolyticus challenge. Knockdown of EsCYLD in hemocytes promoted the cytoplasm-to-nucleus translocation of transcription factor Relish under V. parahaemolyticus stimulation and increased the expression of corresponding antimicrobial peptides. In vivo, silencing of EsCYLD promoted the removal of bacteria from the crabs and enhanced their survival. In addition, interfering with EsCYLD expression inhibited apoptosis of crab hemocytes caused by V. parahaemolyticus stimulation. In summary, our findings revealed that EsCYLD negatively regulates the nuclear translocation of Relish to affect the expression of corresponding antimicrobial peptides and regulates the apoptosis of crab hemocytes, thus indirectly participating in the innate immunity of E. sinensis.