Intestinal miR-29a targets Caveolin-2

Recent studies identified microRNAs (miRNAs) as key regulators of intestinal development showing that their dysregulation may lead to intestinal disease. However, most miRNA-mRNA-interactions are still to be deciphered by functional analyses. The aim of this study was to identify regulated miRNAs and their targets during Salmonella infection using pigs as a model. Because of their close phylogenetic distance to humans, pigs serve as a suitable model for studying intestinal development or disease. Our results showed dysregulation of intestinal miR-29a upon Salmonella infection of piglets. Target prediction of miR-29a using bioinformatical tools revealed Caveolin-2 (CAV2) as a potential target. Interestingly, CAV2 was down-regulated in piglets infected with Salmonella. MiR-29a-CAV2-interaction was verified by luciferase reporter assays. The porcine intestinal epithelial cell line IPECJ-2 and the human cervix carcinoma cell line HeLa were co-transfected with miR-29a mimic and reporter-plasmids harbouring the identified porcine or human CAV2 target site. Reporter-plasmids harbouring the mutated target site as well as a non-sense miRNA served as internal controls. In both cell lines reporter assays resulted in consistent and significant down-regulation of luciferase activity under the control of the CAV2 target site. Our ongoing work concentrates on the regulation of CAV2 protein after miR-29a mimic and anti-miR transfection as well as the verification of the in vivo data using in vitro Salmonella infection models.The study was supported by grants from DFG (SH 465/1-1 & SFB 852 project B4).