Analysis of mRNA and miRNA expression in RAW 264.7 macrophages infected with Salmonella enterica subsp. enterica serovar Dublin in the early stage of infection

Salmonella enterica subsp. enterica serovar Dublin (Salmonella Dublin) is a host-adapted pathogen that causes severe systemic disease in cattle and presents a zoonotic risk to humans. While macrophages play a pivotal role in host defense against Salmonella they are also an intracellular niche for bacterial persistence. However, the mechanism underlying the early transcriptional response of macrophages to Salmonella Dublin infection is poorly understood. This study used high-throughput sequencing to profile mRNA and miRNA expression in RAW 264.7 mouse macrophages 2 h after infection with Salmonella Dublin compared to uninfected control cells. A total of 1,080 differentially expressed (DE) mRNAs were identified, of which 492 were up-regulated and 588 were down-regulated. In addition, 23 DE miRNAs, 18 up-regulated and 5 down-regulated, were identified. Meanwhile, KEGG enrichment analysis indicated significant enrichment of the DE mRNAs and miRNAs in signaling pathways associated with macrophage immune activation, including the TNF, HIF-1, and MAPK signaling pathways, as well as those involved in responses to Salmonella infection. The accuracy of the mRNA sequencing results was verified using RT-qPCR. In conclusion, the findings showed significant up-regulation of Acod1, Ccl22, Bcl2a1b, miR-146-3p, and miR-150-5p in the early stages of Salmonella Dublin infection of mouse macrophages, suggesting the involvement of these molecules in regulating the host immune response.