Transcriptome analysis reveals deep insights into the early immune response of turbot (Scophthalmus maximus) induced by inactivated Aeromonas salmonicida vaccine

Abstract

Non-coding RNAs are a class of RNAs, including circRNA and miRNA, that cannot be translated into proteins, but play an important role in the regulation of the expression of protein-coding genes. More and more evidences showed that circRNA can regulate the expression of miRNA target genes by adsorbing miRNA and form the circRNA-miRNA-mRNA regulatory network. The inactivated Aeromonas salmonicida vaccine is a commercial vaccine for many teleost. Understanding the role of circRNA and miRNA in the early stage of vaccine injection will provide a new insight for the study of the early immune response process in teleost. In this study, the expression profiles of circRNA, miRNA and mRNA were analyzed by high-throughput sequencing at 6 h, 12 h, 24 h and 96 h after injection of inactivated Aeromonas salmonicida vaccine and normal turbot spleen. Compared with the control group, 111, 141 and 453 differentially expressed circRNAs, miRNAs and mRNAs were identified in the four vaccination groups, respectively. The targeting relationships of differentially expressed miRNA to circRNA and mRNA were predicted by using miRanda software, and the results showed that a variety of differentially expressed immune-related genes were targeted. A total of 53 differentially expressed circRNA-miRNA-mRNA regulatory networks were constructed according to circRNA-miRNA pairs and miRNA-mRNA pairs. Among them, cell adhesion molecule 3 and immunoglobulin superfamily member 21 were regulated by the same miRNA (novel_880) and circRNA (novel_circ_0000311/novel_circ_0005326). These suggest that these circRNA-miRNA-mRNA regulatory networks may be a multi-molecule regulatory network, and its regulatory mechanism needs to be further studied.