Mononuclear phagocyte populations are characterized by specific miRNA-expression profiles. (A) Schematic of the development and relationship between the populations of the mononuclear phagocyte network. Framed and colored populations were sorted and investigated in this study. (B) Principal component analysis of the miRNA microarray results obtained from the 8 phagocyte populations. Each symbol represents a microarray dataset and for each population, color-coded as in panel A, duplicates were performed. (C) Hierarchal clustering of miRNA-profiling data revealed a clear separation of the various cells and reflects the developmental relationships consistent with the established tree. (D) K-means clustering of miRNAs that showed an at least 2-fold differential expression in 1 of the 8 cell populations tested. A total of 136 miRNAs could be divided into 7 defined clusters. Intensities of red and blue refer to increased or decreased miRNA expression, respectively. The full list of miRNAs and expression values can be found in supplemental Table 1. (E) Mean arbitrary expression signal intensities for 4 representative miRNAs of cluster 1-7. Normalized and standardized expression levels obtained from the 2 individual miRNA chips as depicted in supplemental Table 1 were averaged and converted to anti-log arbitrary expression values. Note the high expression of miR-142 in the DC compartment.