Research Note: IsomiRs of chicken miR-146b-5p are activated upon Salmonella enterica serovar Enteritidis infection.

In order to enrich the knowledge of chicken transcriptomic response to Salmonella enterica serovar Enteritidis infection, 2-day-old chicks were orally inoculated with this bacteria (1.0 × 10 cfu/mL), and then the cecum tissues of 3 days post-inoculation were utilized for RNA sequencing (6 replicates each for treatment group and control group). After analysis, we found a variety of inflammatory genes were triggered at the mRNA level upon infection. Notably, the expression profiles at the miRNA level and the isomiR level were heterogeneous. Certain isomiRs of chicken miR-146b-5p were significantly increased by more than 2 times compared to control (Padj < 0.05). Combining the bioinformatics prediction, transcriptome data and RT-qPCR results, we deduced that the isomiRs of chicken miR-146b-5p might act to sustain the RIG-I-like receptor signaling and type I interferon induction by repressing USP3 transcript. Our findings provide a new perspective on the regulatory function of miR-146b-5p and facilitate the study of isomiRs.