Stepwise conversion methods between ground states pluripotency from naïve to primed.

Pluripotent stem cells (PSCs) are in vitro adaptations of in vivo pluripotency continuum and can be broadly classified into naïve state characteristic of pre-implantation epiblast and primed state resembling peri-gastrulation epiblasts. Naïve and primed PSCs differ in their cellular and molecular characteristics, e.g., molecular mechanisms for maintaining undifferentiated state. Naïve-to-primed PSC transition provides a tractable in vitro model to study pluripotency development in vivo. We previously developed a protocol that enabled high-efficient (100%) and homogenous derivation of ground state of primed epiblast stem cells (rsEpiSCs) by culturing the isolated post-implantation mouse epiblast under the culture condition containing FGF2 and a Wnt signaling inhibitor (IWR1) (F/R1 condition). Based on F/R1 condition, in this study, we developed three naïve-to-primed conversion methods for generating rsEpiSCs from naïve ground state of mouse ESCs (2i/LIF condition). We found that stepwise methods, but not directly, were effective for bona fide rsEpiSCs conversion from mouse ESCs. In sum, we established a robust and efficient ground states of naïve-to-primed PSC conversion strategy that will facilitate the study of genetic, epigenetic and metabolic processes involved in pluripotency progression in vivo.