TLR5b-mediated NF-KB activation promotes neutrophil recruitment to defense Edwardsiella piscicida infection in zebrafish

NF -KB signaling pathway plays important roles in innate immunity, which could response to various microbials infection and mediate immune defense. It has been reported that NF -KB signaling could be activated after Edwardsiella piscicida infection in zebrafish, while the molecular mechanism of NF -KB signaling in defensing against E. piscicida remains largely unknown. Herein, we use an in vivo NF -KB detection model in larvae, and confirm that the NF -KB signaling pathway was activated by upstream receptor TLR5b through recognizing the flagella of E. piscicida. Besides, we explore the expression of immune-related genes which regulated by NF -KB during infection. Specifically, NF -KB activation upregulates the expression of cxcl8a, promoting the recruitment of neutrophils. Moreover, we prove that NF -KB signaling activation decrease the colonization of E. piscicida and rescue the mortality of larvae. Taken together, our study reveals that TLR5b-mediated NF -KB activation promotes cxcl8a-dependent neutrophils recruitment to defense E. piscicida infection in zebrafish, which contributes to better understanding the mechanism of NF -KB signaling activation in teleost fish.