Project description:Classical mouse embryology has established a paradigm of early development drivenby sequential lineage bifurcations. Accordingly, mouse embryonic stem cells derivedfrom early epiblast have lost the potency to produce extraembryonic trophectoderm.We show in contrast that human naive epiblast cells readily make trophectoderm.Inhibition of ERK signalling, instrumental in naive stem cell propagation, unexpectedlypotentiates trophectoderm formation, an effect enhanced by Nodal inhibition.Transcriptome analyses authenticate conversion into trophectoderm with subsequentproduction of syncitiotrophoblast, cytotrophoblast and trophoblast stem cells. Geneticperturbations indicate that NANOG suppresses and TFAP2C enables trophectoderminduction. Consistent with post-implantation progression, trophectoderm potential isextinguished in conventional human pluripotent stem cells, which instead makeamnion. Finally, human embryo epiblasts from late blastocysts efficiently generatetrophectoderm and differentiated trophoblast. Thus, pluripotent cells in the humanembryo retain extraembryonic lineage plasticity and regenerative potential untilimplantation. Harnessing this unanticipated regulative capacity may be beneficial forassisted reproduction technology.
Project description:Classical mouse embryology has established a paradigm of early development drivenby sequential lineage bifurcations. Accordingly, mouse embryonic stem cells derivedfrom early epiblast have lost the potency to produce extraembryonic trophectoderm.We show in contrast that human naive epiblast cells readily make trophectoderm.Inhibition of ERK signalling, instrumental in naive stem cell propagation, unexpectedlypotentiates trophectoderm formation, an effect enhanced by Nodal inhibition.Transcriptome analyses authenticate conversion into trophectoderm with subsequentproduction of syncitiotrophoblast, cytotrophoblast and trophoblast stem cells. Geneticperturbations indicate that NANOG suppresses and TFAP2C enables trophectoderminduction. Consistent with post-implantation progression, trophectoderm potential isextinguished in conventional human pluripotent stem cells, which instead makeamnion. Finally, human embryo epiblasts from late blastocysts efficiently generatetrophectoderm and differentiated trophoblast. Thus, pluripotent cells in the humanembryo retain extraembryonic lineage plasticity and regenerative potential untilimplantation. Harnessing this unanticipated regulative capacity may be beneficial forassisted reproduction technology.
Project description:Transcriptomic analysis confirms the trophoblast identity of the naïve pluripotent stem cell derived TSC cultures by comparing to the placenta derived TSC culture.
Project description:Reversion from primed to naïve pluripotent status has been achieved by various signaling manipulation, but it is still unclear what signaling is the actual driving force to get over the hurdle from primed to naïve pluripotency. We previously reported that activation of AMP kinase (AMPK) contributed to maintenance of naïve pluripotency. Here, we further show that AMPK activators, AICAR, A769662 or metformin, can induce the reversion of primed mouse epiblast stem cells (mEpiSCs) to naïve pluripotent state. Primed mEpiSCs in our naïve cell culture condition with leukemia inhibitory factor (LIF) and 2 kinase inhibitors (2i) (2iL) never gave rise to naïve state cells. Addition of AICAR alone even in the absence of 2iL or either of AMPK inhibitors with LIF induced appearance of naïve-like cells from primed mEpiSCs. Through maintenance and passages of these cells in 2iL condition, clear naïve-like morphology colonies were purely obtained. They showed core naïve protein expression, and global naïve gene expression profiles. These cells contributed to chimeric mice including germline transmission. Inhibition of p38 signaling abolished the AMPK-elicited reversion and forced activation of p38 in primed mEpiSCs partially reproduced the naïve cell induction, suggesting that p38 is one of the critical downstream in AMPK activation. AMPK pathway should be a novel critical driving force in reversion of primed to naïve pluripotency.
Project description:The epiblast is the first cell type that forms apical-basal polarity de novo as the mouse embryo implants into the maternal uterus, while the extraembryonic neighbours of the epiblast - trophectoderm and primitive endoderm - retain their pre-established polarity beyond implantation [1]; however, it is still unclear how the epiblast establishes apical-basal polarity de novo. Here, we focused on Rap1 signaling pathway, which is activated during the transition of the epiblast from the naïve to primed state of pluripotency during implantation [2]. Through the preestablished in vitro three-dimensional culture system [3], genetic knockouts and proximity-biotinylation analyses, we found that Rap1 integrates multiple signals that contribute to de novo formation of apical-basal polarity. Importantly, formation of apical-basal polarity in the epiblast is essential for its correct patterning and proper communication with the extraembryonic lineages. Altogether, these results not only dissect molecular details of de novo apical-basal polarity formation, but also have broader implications for epithelial polarity and development.
Project description:Reversion from primed to naïve pluripotent status has been achieved by various signaling manipulation, but it is still unclear what signaling is the actual driving force to get over the hurdle from primed to naïve pluripotency. We previously reported that activation of AMP kinase (AMPK) contributed to maintenance of naïve pluripotency. Here, we further show that AMPK activators, AICAR, A769662 or metformin, can induce the reversion of primed mouse epiblast stem cells (mEpiSCs) to naïve pluripotent state. Primed mEpiSCs in our naïve cell culture condition with leukemia inhibitory factor (LIF) and 2 kinase inhibitors (2i) (2iL) never gave rise to naïve state cells. Addition of AICAR alone even in the absence of 2iL or either of AMPK inhibitors with LIF induced appearance of naïve-like cells from primed mEpiSCs. Through maintenance and passages of these cells in 2iL condition, clear naïve-like morphology colonies were purely obtained. They showed core naïve protein expression, and global naïve gene expression profiles. These cells contributed to chimeric mice including germline transmission. Inhibition of p38 signaling abolished the AMPK-elicited reversion and forced activation of p38 in primed mEpiSCs partially reproduced the naïve cell induction, suggesting that p38 is one of the critical downstream in AMPK activation. Single cell RNA-seq analysis under AICAR stimulation successfully demonstrated the reversion process with appearance of intermediate naïve-like population. AMPK pathway should be a novel critical driving force in reversion of primed to naïve pluripotency.