MicroRNA-146 function in the innate immune response of zebrafish embryos to Salmonella typhimurium infection [RNA-seq]
We used zebrafish embryos as an in vivo system to investigate the role of the microRNA-146 family (consisting of 2 members miR-146a and miR-146b) in the innate immune response to S. typhimurium infection.  To determine the role of miR-146 microRNAs in the response to S. typhimurium infection we used Illumina RNA sequencing to compare the mRNA expression profiles of control embryos versus embryos with  knockdown of miR-146a and miR-146b. RNA sequencing analysis of miR-146 knockdown embryos showed no major effects on pro-inflammatory gene expression or on the expression of transcriptional regulators and signal transduction components of the immune response. In contrast, apoliprotein-mediated lipid transport emerged as an infection-inducible pathway under miR-146 knockdown conditions, suggesting a function of miR-146 in regulating lipid metabolism during inflammation. Overall design: Embryos were injected at the one cell stage with a combination of two morpholinos targeting miR-146a and miR-146b, or with the standard control morpholino from GeneTools. Subsequently, at 28 hours post fertilzation (hpf) they were infected by injecting 200-250 colony forming units of S. typhimurium strain SL1027 into the caudal vein, or mock-injected with PBS. RNA was isolated at 8 hours post injection (hpi) for Illumina RNAseq analysis. Two independent experiments were performed for RNAseq analysis of biological duplicates.