Title : Altering stem cell states by controlling cell signaling information
Abstract:
Cell fate determination induced by cell signaling is central to stem cells and regenerative medicine. Pluripotent stem cells such as embryonic stem cells (ESC) are an attractive model for understanding the relationship between cell signaling and cell fates. Cultured mouse ESCs are heterogeneous and can exist in multiple cell states such as Totipotent, Pluripotent, Primed and Primitive Endoderm. Such heterogeneity can compromise stem cell applications. The signaling mechanisms regulating the Totipotent state acquisition and coexistence of these multiple cell states are poorly understood. In this study, we identify BMP4 as an inducer of the Totipotent state. However, we discovered that BMP4-mediated induction of the Totipotent state is constrained by the cross-activation of FGF, TGF-b and WNT pathways. We exploited this finding to enhance the proportion of Totipotent cells in ESCs by rationally inhibiting the cross-activated pathways using small molecules. Next, we utilized single-cell mRNA-sequencing (scRNA-seq) to analyze the resulting impact on cellular heterogeneity. The scRNA-seq analysis revealed that induction of the Totipotent state is accompanied by the suppression of both the Primed and Primitive Endoderm states, thus reducing the overall stem cell heterogeneity. Furthermore, the reprogrammed Totipotent cells generated in culture have a molecular and functional resemblance to Totipotent cell stages of the preimplantation embryo. Our findings reveal a BMP4 signaling mechanism in ESCs to regulate multiple cell states, potentially significant for managing stem cell heterogeneity in differentiation and reprogramming.
