Transcriptome Analysis Reveals the Regulation Role of miR-144-5p in Intestinal Immunity of Japanese Flounder (Paralichthys olivaceus)

MicroRNAs (miRNAs), 22-nucleotide-long micromanagers that guide the post-transcriptional regulation of a wide range of target genes, can theoretically be used as a diagnostic or therapeutic target for inflammatory reaction. In fish, miR-144-5p expression varies dramatically in response to the different bacterial infections and can regulate immunity-related genes to reduce the occurrence of inflammation. In this research, the regulation function of miR-144-5p to the intestinal innate immunity was udied in flounder Paralichthys olivaceus. The flounders were interfered by 2 µg g miR-144-5p antagomir and their tissues (intestine, liver and spleen) were harvested from the fish at 12 h post-injection. More than 60 million high-quality reads were collected. At 24 hours after miR-144-5p or miR-NC interference, a total of 2704 and 1823 different-expresion genes (DEGs) were identified in comparison with control group, respectively. The DEGs were enriched in a variety of immunity-related signaling pathways, including NOD-like receptor, Wnt and Toll-like receptor signaling pathways, according to GO and KEGG analyses. A total of 503 highly interacting DEGs engaged in 33 immunity-related signaling pathways were discovered using KEGG analyses. Additionally, 5 hub genes were found by protein-protein interaction networks, which formed an intricate immune regulation network. Meanwhile, these hub genes were mostly involved in focal adhesion, Wnt signaling pathway, as well as the Intestinal Immune Network for IgT (IgA) Production Pathway. In conclusion, the loss of miR-144-5p can affect immunity-related genes and downstream signaling pathways. Our findings suggest that miR-144-5p is a modulator of gene networks and signaling pathways associated with intestinal innate immunity.