Esrrb plays an important role in maintaining self-renewal of trophoblast stem cells (TSCs) and reprogramming somatic cells to induced TSCs [RNA-Seq]

Trophoblast stem cells (TSCs) are derived from the trophoectoderm of a blastocyst and can maintain self-renewal in vitro. Meanwhile, essential insights into the molecular mechanisms controlling placental developmental could be gained by using TSCs that can differentiate into the various placental trophoblast cell types in vitro. Esrrb is a transcription factor with pivotal roles in maintaining TSCs’ self-renewal, but the exact transcriptional networks that Esrrb involved in TSCs are largely unknown. In the present study, we elucidated the function of Esrrb during TSC self-renewal and differentiation. We demonstrate that precise levels of Essrb are critical for TSCs stemness maintenance and normal trophoblast differentiation, as Esrrb depletion results in down-regulation of the key TSC-specific transcription factors, consequently causing TSCs differentiation and forced expression of Esrrb can partially block TSCs differentiation in the absence of FGF4. This function of Esrrb is exerted by directly binding and activating a core set of TSC-specific target genes including Cdx2, Eomes, Sox2, Fgfr4 and BMP4. Furthermore, we investigate the role of Esrrb in reprogramming of mouse embryonic fibroblasts (MEFs) to induced TSCs (iTSCs). We show that Esrrb can facilitate the conversion of iTSCs from MEFs. Moreover, Esrrb can substitute for Eomes during this conversion process. Our findings provide a better understanding of the molecular mechanism of Esrrb in maintaining TSCs self-renewal and iTSCs reprogramming.