Interaction analysis of miRNA and mRNA reveals the regulatory mechanism of immune response in golden pompano (Trachinotus ovatus) spleen to Streptococcus iniae infection.

Streptococcus iniae is a major warm-water pathogen that cause high mortality and severe economic losses in golden pompano industry. In the present study, we performed the mRNA-miRNA integrated transcriptomic analysis of spleen of golden pompano challenged with S. iniae to explore the possible regulatory mechanism to bacterial infection. In total, we excavated 5072 DEGs, of which 2765 up-regulated and 2307 down-regulated genes. KEGG enrichment analysis indicated that the DEGs were primarily enriched in immune-related pathways, such as proteasome, cytokine-cytokine receptor interaction, p53 signaling pathway, lysosome, phagosome, Herpes simplex virus 1 infection. Additionally, a protein-protein interaction (PPI) network was constructed to extract hub genes. And the result showed that 4 hub genes, comprising cd4, il10, tnfsf2, myd88, may play vital roles in response to S. iniae infection. Furthermore, a total of 46 differentially expressed miRNAs (DEMs) were identified, containing 23 known and 23 novel DEMs. By integrating mRNA and miRNA joint analysis, we established a miRNA-mRNA regulatory network, including 12 miRNAs and 14 genes. Among them, novel-miR-357 were identified as a multi-target hub miRNA. These results provide important insights into the molecular regulatory mechanisms of immune response and inflammation processes in the defense of golden pompano against S. iniae infection.