The involvement of ecdysone and ecdysone receptor in regulating the expression of antimicrobial peptides in Chinese mitten crab, Eriocheir sinensis. (October 2020) - Huang, Shu
Abstract: The ecdysone, 20-hydroxyecdysone (20E) and ecdysone receptor (EcR), are regarded as the key regulators of development, metamorphosis, and growth in arthropods. In the present study, the role of 20E and Es EcR in regulating the expression of antimicrobial peptides (AMPs) was investigated in Chinese mitten crab, Eriocheir sinensis . The concentration of 20E in plasma was significantly ( p < 0.05) up-regulated from 3 h to 12 h after lipopolysaccharide (LPS) stimulation. The mRNA expression level of Es EcR-4 in hemocytes was significantly ( p < 0.01) up-regulated from 6 h to 24 h after LPS stimulation, while no significant changes of Es EcR-2 and Es EcR-3 transcripts were observed. After 20E injection, Es EcR-4 expression level was significantly increased from 12 h to 48 h with the highest level at 24 h (4.34-fold compared to the control group, p < 0.01), and the mRNA expression levels of AMPs ( Es ALF-2, Es LYZ and Es Crus) in hemocytes were significantly increased from 6 h to 24 h with the peak level of 2.93-fold ( p < 0.01), 2.33-fold ( p < 0.01) and 2.75-fold ( p < 0.01) at 12 h, respectively. After Es EcR-4 expression was interfered with specific dsRNA, a significant reduction of Es ALF-2 (0.56-fold compared to the control group, p < 0.01), Es LYZ (0.27-fold, p < 0.01) and Es Crus (0.41-fold, p < 0.01) mRNA expression level was observed in ds Es EcR-4+LPS group at 12 h post LPS stimulation. Moreover, the mRNA expression levels of Es Dorsal and Es JNK in hemocytes were significantly ( p < 0.05) increased from 6 h to 24 h post 20E injection, and the phosphorylation of Dorsal and JNK in the hemocytes were significantly ( p < 0.01) up-regulated at 3 h post 20E injection, while that in ds Es EcR-4+LPS group were significantly decreased after LPS stimulation compared to ds Es EGFP+LPS group. Taken together, these results suggested that 20E and Es EcR-4 play important roles in regulating the expression level of AMPs in the immune responses of E . sinensis by regulating the mRNA expression level and phosphorylation of Dorsal and JNK. Highlights: The 20E concentration and Es EcR mRNA expression were up-regulated by LPS stimulation. The transcripts of AMPs increased after 20E injection, while decreased after inhibition of Es EcR-4. The phosphorylation of Dorsal and JNK was increased after 20E injection. The phosphorylation of Dorsal and JNK was decreased after the inhibition of Es EcR-4.