Totipotent-Like Cell-Based Embryo Model Recapitulating Mouse Embryogenesis from Pre-Implantation to Gastrulation [RNA-Seq]

The development of stem-cell-derived models of mammalian embryogenesis has provided invaluable tools for investigating embryo development. However, constructing embryo models that can continuously recapitulate the full developmental trajectory, from zygotic genome activation (ZGA) to gastrulation, remains a major challenge. Here, we developed a new chemical cocktail to induce totipotent-like cells with robust proliferation ability, and leveraged these cells to establish a stepwise protocol to generate a continuous embryo model. This model sequentially mimics mouse embryogenesis from embryonic day 1.5 to 7.5. It recapitulates key developmental milestones, including ZGA in 2-cell embryos, the diversification of embryonic and extraembryonic lineages from 4-cell to 64-cell stages, the formation of blastocysts, and the subsequent development into post-implantation egg cylinders. Notably, these structures can undergo gastrulation, as evidenced by primitive streak formation and the subsequent emergence of several hallmarks of early organogenesis. Our study opens new avenues for modeling mammalian embryogenesis in vitro. Overall design: A series of bulk RNA-seq data were analyzed, including EPSCs under 6 conditions: E (EPSC), C (EPSC + CHIR-99021), CE (EPSC + CHIR-99021 + Elvitegravir), CP (EPSC + CHIR-99021 + PD0325901), CCD2 (EPSC + CHIR-99021 + CD1530), and "all" (EPSC + all small molecules); long-term passaged S1 samples (P25, P38); S2, S3, S5, and their corresponding samples treated with drug combinations minus one agent; as well as mESCs, mESC-derived S1.