Differential miRNA content in BMDC-derived immature and mature exosomes. (A) Correlation plot of exosome miRNAs, indicating in red those miRNAs expressed differentially by immature and mature exosomes. (B) Expression pattern grid with miRNAs expressed differentially by immature and mature exosomes. Each box corresponds to a gene for a given sample of an experimental group. If the individual sample expression value for that miRNA is > 95 percentile of the same miRNA from the other sample group (considered as a group), it is colored red. If that individual miRNA expression value is < 5 percentile of the same miRNA from the other experimental group, it is painted green. If the expression value falls within the range of the 5th and 95th percentiles, it is represented as a black square. The groupings of miRNAs fall out logically according to the counts of the colored squares; the predominantly red and green group represents those miRNAs whereby the miRNA is overexpressed in all mature exosome samples (group a), or in all immature exosomes samples (group e). Group b represents miRNAs whereby the trend is toward overexpression in mature exosomes, and so on. The 2 main groups of most reliable differences are groups a and e. The black versus black (ie, group f) is actually miRNAs that have equal numbers of squares colored red, green, and black and are, therefore, not actually different; the measure of difference being high for such miRNAs may be because of outliers. Four independent samples of each type of exosome were analyzed.