Derivation and transcriptional profiling analysis of pluripotent stem cell lines from rat blastocysts.

Embryonic stem (ES) cells are derived from blastocyst-stage embryos. Their unique properties of self-renewal and pluripotency make them an attractive tool for basic research and a potential cell resource for therapy. ES cells of mouse and human have been successfully generated and applied in a wide range of research. However, no genuine ES cell lines have been obtained from rat to date. In this study, we identified pluripotent cells in early rat embryos using specific antibodies against markers of pluripotent stem cells. Subsequently, by modifying the culture medium for rat blastocysts, we derived pluripotent rat ES-like cell lines, which expressed pluripotency markers and formed embryoid bodies (EBs) in vitro. Importantly, these rat ES-like cells were able to produce teratomas. Both EBs and teratomas contained tissues from all three embryonic germ layers. In addition, from the rat ES-like cells, we derived a rat primitive endoderm (PrE) cell line. Furthermore, we conducted transcriptional profiling of the rat ES-like cells and identified the unique molecular signature of the rat pluripotent stem cells. Our analysis demonstrates that multiple signaling pathways, including the BMP, Activin and mTOR pathways, may be involved in keeping the rat ES-like cells in an undifferentiated state. The cell lines and information obtained in this study will accelerate our understanding of the molecular regulation underlying pluripotency and guide us in the appropriate manipulation of ES cells from a particular species.