Depletion of <i>Sorcs3</i> Activates Totipotency in Mouse Embryonic Stem Cells by Modulating Key Signaling Pathways

Totipotency represents the greatest potential to yield an entire individual alongside its associated extraembryonic tissues, albeit transiently. Nevertheless, achieving sustainable totipotent stem cells remains an intriguing yet challenging endeavor. Here, it is reported that Sorcs3 depletion in murine embryonic stem cells (ESCs) enables robust differentiation into both embryonic and extraembryonic lineages, resulting in a totipotent-like state. Notably, Sorcs3 knockout (SKO)-ESCs can efficiently self-assemble into typical blastocyst-like structures, offering a versatile model for studying early embryonic development. Comprehensive analyses reveal that totipotency in SKO-ESCs is related to Tfap2c gene activation. Deletion of Tfap2c significantly reduces the developmental potential of SKO-ESCs across all the examined phenotypes, underscoring its critical role. Furthermore, single-cell transcriptome analysis of SKO-ESCs reveals that inhibition of the TGF-β, PI3K-AKT, and lysosome pathways drives totipotency activation, which is validated by the introduction of corresponding inhibitors into wild-type ESC cultures. Together, the findings facilitate the establishment of totipotent stem cells in a defined medium and provide a universal platform for studying totipotency.