Effect of wt versus mutant hsa-miR-122 overexpression on spontaneous hESC differentiation

We aimed to determine whether overexpression of endoderm-specific miRNA may affect hESC differentiation. To this end, we analyzed the effect of lentiviral-based overexpression of liver-specific miR-122 on hESC differentiation, using genomewide gene microarrays. Stable overexpression of endoderm-specific miR-122 in hESC resulted in increased expression of a few endodermal markers in spontaneously-differentiating hESC, but had no clear effect on directing differentiation towards an endodermal fate; rather, it delayed the general differentiation of hESC. Lentiviral vectors encoding either wt or mutant (control) hsa-miR-122 were transduced into hES cells (line HES2). The cells differentiated spontaneously in KO medium without feeder cells for 2 weeks, and the gene expression profile of wt- vs mutant-expressing miR-122 was compared. We used for this study 3 arrays for control (mutant miR) and 2 arrays for the treatment (wt miRNA).