A chemically defined system supports two distinct types of stem cell from a single blastocyst and their self-assembly to generate blastoid

Abstract: The pluripotent stem cells exist in a narrow window during early development and its derivation depends on intrinsic and extrinsic growth signaling in vitro. It has remained challenging to derive two or three distinct cell lines that are representative of blastocyst-stage lineages from one preimplantation embryo simultaneously in a chemical defined condition. Therefore, it is desirable to establish a system by manipulating extrinsic signaling in culture to derive multiple types of stem cells from a single blastocyst. Here, we report that a defined medium containing Activin A, WNT activator and LIF (ACL medium), enables establishment of ACL-ESCs and ACL-XEN cells from one blastocyst. Our results indicate that ACL-ESCs and ACL-XEN cells represent ICM and PrE lineages of blastocyst. Importantly, we obtained ACL-blastoid from ACL-ESCs and ACL-XEN cells self-aggregation, partially recapitulating early development and initiation of early implantation events. This study would not only provide a culture system for derivation and maintenance of two types of cell lines corresponding to ICM as well as PrE, but also deepen our understanding of early embryogenesis and widen insights into translational application of stem cells.