Expression profiles of miRNAs in polarized macrophages.

microRNAs (miRNAs) play a crucial role in tissue development and the pathology of various diseases. However, the effects and roles of miRNAs in macrophage polarization have yet to be investigated. In this study, we analyzed and compared the miRNA expression profiles of bone marrow-derived macrophages (BMDMs) with two distinct polarizing conditions (classical macrophage activation 'M1' and alternative activation 'M2') using miRNA microarray. In total, 109 miRNAs were differentially expressed between M1 and M2. The differential expression of selected miRNAs was validated by real-time qRT-PCR: miR-181a, miR-155-5p, miR-204-5p and miR-451 were upregulated (fold change >2, P<0.05) and miR-125-5p, miR-146a-3p, miR-143-3p and miR-145-5p were downregulated (fold change <-2, P<0.05) in M1 compared with M2. In conclusion, our study may be useful for exploring the precise roles of miRNAs in macrophage differentiation and polarized activation processes in the future.