microRNA expression profiling of polarized macrophages

microRNAs are small non-coding RNAs that regulate gene expression at a post-translational level, and play a crucial role in the development of cells of the immune system. Macrophages are essential for generating inflammatory reactions upon tissue damage and encountering of invading pathogens, yet modulation of their immune responses is critical for maintaining tissue homeostasis. Macrophages can present different phenotypes, depending on the cytokine environment they encounter in the affected tissues. In this study, we have identified expression signatures of miRNAs that are differentially regulated during maturation of monocytes and polarization of macrophages by cytokines. We present a comprehensive characterization of miRNA expression in human monocytes and M1, M2a and M2c polarized macrophages, using next-generation Sequencing by Oligonucleotide Ligation and Detection (SOLiD). We have analyzed freshly isolated human monocytes and 5 day monocyte-derived macrophages unstimulated, or stimulated with IFNgamma+TNFalpha (M1), IL-4 (M2a) or IL-10 (M2c).