microRNA profile of bovine monocyte-derived macrophages infected in vitro with Streptococcus agalactiae

In a subclinical infection such as bovine streptococcal mastitis, early recognition is a great challenge, and miRNAs profiling could potentially assist in the diagnosis and contribute to the understanding of pathogenicity and defense mechanisms. We have examined the miRNA repertoire during the early phase response of bovine macrophages to in vitro infection with live Streptococcus agalactiae. Next generation sequencing of 20 small RNA libraries from blood monocyte-derived macrophages exposed to two sequence types of S. agalactiae (ST103 and ST12) for 6 hours in vitro was performed. Analyzes of over 356 million of high quality sequence reads, revealed that 17 and 44 miRNAs were differentially expressed (P < 0.05) between the control unchallenged macrophages and the macrophages infected with ST103 and ST12, respectively. We also identified the expression of 31 potentially novel bovine miRNAs.