miR-23a-3p and miR-23a-5p target CiGadd45ab to modulate inflammatory response and apoptosis in grass carp.

Ctenopharyngodon idella growth arrest and DNA damage-inducible 45 ab (CiGadd45ab) is a subtype of the Gadd45a gene of the Gadd45 family in grass carp. There is increasing evidence that microRNAs (miRNAs) are involved in the regulation of inflammatory and apoptotic responses. However, little is known about the regulatory effects of miRNAs on CiGadd45ab expression. In the present study, CiGadd45ab was identified as a target gene of miR-23a-3p and miR-23a-5p, based on miRNA expression profiling and a dual-luciferase reporter assay. In addition, miR-23a-3p and miR-23a-5p were both confirmed to be involved in the inflammatory response following infection with Aeromonas hydrophila by targeting CiGadd45ab. Transfection with miR-23a-3p and miR-23a-5p mimics and inhibitor altered proinflammatory gene expression and apoptosis rate, thereby suggesting that miRNAs regulate immune response and anti-apoptosis by targeting CiGadd45ab in grass carp. Our results provide a theoretical basis for exploring the molecular mechanisms by which miR-23a-3p and miR-23a-5p target CiGadd45ab to regulate inflammation and apoptosis against bacterial infection in grass carp.