microRNA expression profiling of human myeloid precursors

Hemopoiesis entails a series of hierarchically organized events that proceed throughout cell specification and terminates with cell differentiation. Commitment needs the transcription factors effort that, in concert with microRNAs, drives cell fate specification, answering to promiscuous patterns of gene expression by turning on lineage-specific genes and repressing alternate lineage transcripts. Therefore microRNAs and mRNAs cooperate to direct cell fate decisions. We obtained microRNAs profiles from human CD34+ hemopoietic progenitor cells and in-vitro differentiated erythroblasts, megakaryoblasts, monoblasts and myeloblasts precursors and we analyzed them together with the gene expression profiles of the same populations. We found that for most part of microRNAs specifically up-regulated in one single cell progeny an inverse correlation between microRNAs and down-regulated putative targets expression levels occurs. We chose hsa-mir-299-5p as a model to get further insights into the possible biological relevance of this microRNAs-mRNAs expression integrated analytical approach and we asked if the forced expression of a single lineage-specific microRNA is able to control the cell fate of CD34+ progenitors grown in multilineage culture conditions. Gain and loss of-function experiments established that mir-299-5p regulates hemopoietic progenitors fate modulating reciprocally megakaryocytic-granulocytic versus erythroid-monocytic differentiation and has at least two genuine targets, the transcription factors CTCF and SOX4. Total cellular RNA was extracted from five CD34 HPCs, MYELO, MONO, MKC and ERY populations Five RNAs for each cellular context were then pooled and miroRNA expression profiles were analyzed by means of RealTime-PCR TaqMan MicroRNA Assays Human Panel Early Access Kit (Life Technologies-Applied Biosystems)