Generation of Transient Totipotent Blastomere-like Stem Cells by Short-term High-dose Pladienolide B Treatment

As an alternative model for studying the dynamic process of early mammalian embryonic development, much progress has been made in using mouse embryonic stem cells (mESCs) to generate embryo-like structures, especially by modifying the starting cells. A previous study has demonstrated that totipotent blastomere-like cells (TBLCs) can be obtained by continuous treatment of mESCs with a low-dose splicing inhibitor, Pladienolide B (PlaB). However, these totipotent mESCs have limited proliferative capacity. Here, we report that short-term high-dose PlaB treatment can also induce mESCs to acquire totipotency. This treatment equips this novel type of stem cells with the ability to self-organize into blastoids and recapitulate key preimplantation developmental processes. Therefore, the stem cells are termed transient totipotent blastomere-like stem cells (tTBLCs). Transcriptome analysis showed that tTBLC blastoids bore similarities to mouse E3.5 blastocysts, E4.5 blastocysts, and TBLC blastoids. Additionally, we found that tTBLC blastoids could develop beyond the implantation stage, forming egg-cylinder-like structures both in vitro and in vivo. In summary, our research provides an alternative rapid and convenient method to generate the starting cells capable of developing into blastoids, which have immense application in various fields, not only in the basic study of early mouse embryogenesis but also in high-throughput drug screening.