LncRNA MIR144HG-derived miR-144 suppresses antibacterial signaling and facilitates bacteria escape in fish

Abstract

Growing number studies show that lncRNA is an important regulatory factor and plays an irreplaceable role in innate immunity. However, most studies on lncRNA have focused on mammals and it is unknown in lower vertebrates. In this study, we identify a new lncRNA, named MIR144HG, which can have a negative role in antibacterial immunity of Miichthys miiuy caused by Vibrio anguillarum and V. harveyi. MyD88, TAK1 and p65 are very important pathway genes in antibacterial innate immune responses, whether in mammals or lower vertebrates. Here, we found that miR-144–3p could target MyD88, TAK1 and p65, inhibit host antibacterial response and promote bacterial escape. Further studies found that miR-144–3p can be derived by MIR144HG, and finally enhance the inhibitory effect of miR-144–3p on host antibacterial immunity. Moreover, V. anguillarum and V. harveyi are the two most susceptible Gram-negative pathogens in aquaculture, and the economic losses caused by these two bacteria are immeasurable every year. Our results not only elucidate the mechanism of the lncRNA-miRNA-mRNA axis in antibacterial immune responses, but also provide new insights for understanding the impact of lncRNA on host immunity and bacteria escape.