A XEN-like state bridges somatic cells to pluripotency during chemical reprogramming. Mus musculus

Pluripotent stem cells can be generated from somatic cells by using pure chemicals.However, the cell fate dynamics and molecular events that occur during the chemical reprogramming process remain unclear. In this study, we found that the chemical reprogramming process requires the early formation of extra-embryonic endoderm (XEN)-like cells and a late transition from XEN-like cells to CiPSCs, a new route that differs from the pathway of transcription factor-induced reprogramming. Moreover, by more precisely manipulating the cell fate transition in a step-wise manner through the XEN-like state, we identified small-molecule boosters and established a robust chemical reprogramming system, with a yield up to 1,000-fold greater than that of the previously reported protocol. These findings demonstrate that chemical reprogramming is a unique and promising approach in the future manipulation of cell fates. Overall design: We analyzed the gene expression profiles of intermediate cells obtained from diferent timepoints during chemical reprogramming process,using RNA-Sequencing. Embryo-derived XEN cells (eXENs), chemically-derived eXEN cell lines (CeXENs), embryonic stem cells (ESCs) and chemically-induced pluripotent stem cells (CiPSCs) are used as controls.