Effect of <i>Aeromonas hydrophila</i> infection on leptin receptor overlapping transcript expression in <i>Rana amurensis</i>

The leptin receptor overlapping transcript (LepROT) has been suggested to play several roles in immunomodulatory mechanisms; however, the understanding of its role in <i>Rana amurensis</i> immunity is still very limited. Here, we performed hematoxylin-eosin staining, quantitative reverse-transcription polymerase chain reaction (qRT-PCR), immunofluorescence and western blotting to investigate the roles of LepROT in the immunomodulatory mechanism and the influence of its expression on the nuclear factor-kappa B (NF-κB) signaling pathway, such as the activation of IκB kinase and NF-кB, in amphibian resistance to infection with <i>Aeromonas hydrophila</i> (<i>Ah</i>). After <i>Ah</i> infection, the liver, lung, kidney, skin, muscle, and stomach of <i>R. amurensis</i> showed cell structure disturbance, bleeding, and texture abnormalities. In addition, the relative expression levels of LepROT, NF-кB, IKKα, and IKKβ were all upregulated after <i>Ah</i> infection; however, they showed time-dependent differential expression. The NF-кB signaling pathway exhibited robust expression levels, which might be explained by the positive feedback regulation function of LepROT. Overall, this study provides a basis for further assessment of the biological functions of LepROT and highlights its role in the regulation of immune mechanisms.