Reprogramming Epiblast Stem Cells into Pre-Implantation Blastocyst Cell-like Cells

Recently, a new wave of synthetic embryo systems (SESs) have been established from cultured cells toward efficient and ethical embryonic development research. We recently reported our epiblast stem cell (EPISC) reprogramming SES that generates numerous blastocyst (BC)-like hemispheres (BCLH) with pluripotent and extraembryonic cell features detected microscopically. Here, we further explored the system over key time points with unprecedented single-cell RNA sequencing (scRNA-seq) analysis and revealed broad induction of the 2C-like reporter MERVL and RNA velocity diverging three major population regions with genetic expression resembling pluripotent epiblast (EPI), primitive endoderm (PE), and trophectoderm (TE). Enrichment of those three BC-like cell fates involved key regulons, zygotic genome activation (ZGA) related genes, specific RNA splicing, and select cells meaningfully distinguished critical regulons of model cells. This analysis confirms the induction of the extraembryonic cell populations during the reprogramming and we anticipate that our unique BCLH SES and rich data may uncover new facets of cell potency, improve developmental biology, and help biomedicine advance.