miR-302 family, miR-145 and miR-296 temporal expression profile along the cell cycle of human pluripotent stem cells

Human pluripotent stem cells (hPSCs), like embryonic (hESCs) and induced pluripotent stem cells (hiPSCs), exhibit an unusual cell cycle structure characterized by a short G1 phase and cells being most of time in S phase. hPSCs are receptive to differentiation cues during their transition through G1 phase when lineage determination is decided. Although several MicroRNAs (miRNAs) have been shown to target transcripts that directly or indirectly coordinate the cell cycle of pluripotent cells, its temporal expression profile along hPSCs cell cycle remains poorly characterized. miR-145 and miR-296 are induced during differentiation and silence the self-renewal and pluripotency program. miR-302 family is essential for hPSCs stemness and its expression decreases during differentiation. We aimed to study how the aforementioned miRNAs are regulated along the cell cycle of hPSCs. We demonstrated by pharmacological synchronization and block and release experiments that miR-145, miR-296 and miR-302 family are periodically expressed in hPSCs. Importantly, miR-302 family expression is induced at G1/S boundary and remained high at S phase, presumably to impede differentiation onset. Besides, we confirmed by a gene ontology analysis that many validated miR-302 family target genes are involved in cell cycle regulation.