Gene expression profiles between miRNA Negative control-treated and miR-124a-3p mimic treated-teratomas

The role of microRNAs (miRNAs) during mouse early development, especially in endoderm germ layer formation, is largely unknown. Here, using miRNA profiling, we discovered that miR-124a negatively regulates endoderm lineage commitment in mouse embryonic stem cells (mESCs). We showed that miR-124a inhibits endoderm differentiation in vitro through targeting the 3’ untranslated region (UTR) of Sox17 and Gata6, revealing the existence of an interplay between miR-124a and Sox17/Gata6 transcription factors in hepato-specific gene regulation. Besides, we proposed an in vivo system that utilizes teratoma to evaluate the functional role of miRNA in lineage specification. We demonstrated that ectopic expression of miR-124a in teratomas suppressed endoderm and mesoderm lineage differentiation while augmented the differentiation of ectoderm lineage. Collectively, our findings suggested that miR-124a plays a significant role in mESCs lineage commitment. Formation of teratomas derived from mESCs was performed in immunodeficiency mouse (BALB/c Nude). Mice were randomly divided into 2 groups (miR-124a vs Control) for in vivo miRNA transfection experiment (n=3 in each group). In vivo miRNA transfection was performed by intratumoral administration of miRNAs: “Atelogen QG” complexes at a final concentration of 15 µg/100 µL. In vivo delivery of miRNAs was performed once every 3 days until Day 28. At the end of the experiment, teratomas were harvested for histological analysis and microarray analysis.