miR-200 modulates coelomocytes antibacterial activities and LPS priming via targeting Tollip in Apostichopus japonicus

In order to explore the potential roles of microRNAs (miRNAs) in regulating Toll-like receptor (TLR) pathways, we identified Toll interacting protein as a putative target of miR-200 in Apostichopus japonicus coelomocytes by RNA-seq screening (denoted as AjTollip). The positive expression profiles of miR-200 and AjTollip were detected in both LPS exposure primary coelomocytes and Vibrio splendidus challenge sea cucumber. Co-infection miR-200 mimics significantly elevated the expression of AjTollip and its down-stream molecules. In contrast, miR-200 inhibitor significantly repressed the expression of these TLR-pathway members. More importantly, miR-200 displayed not only to enhance coelomocytes antibacterial activities, but to suppress LPS priming in vitro. Overall, all these results will enhance our understanding on miR-200 regulatory roles in anti-bacterial process in sea cucumber.