Combined mRNA and microRNA profiling reveals that miR-148a and miR-20b control human mesenchymal stem cell phenotype via EPAS1

International audienceMesenchymal stem cells (MSC) are present in a wide variety of tissues during development of the human embryo starting as early as the first trimester. Gene expression profiling of those cells has focused primarily on the molecular signs characterizing their potential heterogeneity and their differentiation potential. In contrast, molecular mechanisms participating to the emergence of MSC identity in embryo are still poorly understood. In this study, human embryonic stem cells (hES) were differentiated toward MSCs (ES-MSC) to compare the genetic patterns between pluripotent hES and multipotent MSC cells by performing a large genome-wide expression profiling of mRNAs and microRNAs (miRNAs). After whole-genome differential transcriptomic analysis, a stringent protocol was used to search for genes differentially expressed between hES and ES-MSC, followed by several validation steps to identify the genes most specifically linked to the MSC phenotype. A network was obtained that encompassed 74 genes in 13 interconnected transcriptional systems which are likely to contribute to MSC identity. Pairs of negatively correlated miRNAs and mRNAs, which suggest miRNA-target relationships, were then extracted and validation sought using PremiRs. We report here that under-expression of miR-148a and miR-20b in ES-MSCs, as compared to ES, allows an increase in expression of the EPAS1 transcription factor that results in the expression of markers of the MSC phenotype specification

Global transcriptional profiling of neural and mesenchymal progenitors derived from human embryonic stem cells reveals alternative developmental signaling pathways.

International audienceHuman embryonic stem cells can be differentiated along different lineages, providing the possibility of a precise analysis of genes profiles associated with specific commitments. Subtractive gene expression profiling between differentiated and undifferentiated cells provides lists of potential actors in this commitment. This combines, however, genes that are specifically associated with development and others that are over expressed because of nonlineage-specific differentiation systems. As a way to establish gene profiles associated with the neural and/or to the mesodermal commitments of human embryonic stem cells more precisely, we have carried out a 2-step analysis. We first performed a subtractive analysis of gene profiles of each of these lineages as compared to the undifferentiated stage. Then, we extended the analysis by comparing the 2 sets of results with each other. This strategy has allowed us to eliminate large numbers of genes that were over expressed in both sets of results and to uniquely associate different gene networks with either the neural or the mesodermal commitments