Project description:This analysis compares the expression profiles of CGR8 ES cells, E3 epiblast stem cells, and E3R cells (E3 EpiSCs reverted to an ES-like state).
Project description:To characterize the EpiSCs (Epiblast stem cells) we established in our lab, we have employed whole genome microarray expression profiling as a platform to distinguish the EpiSCs (primed state) from ES cells (naïve state).
Project description:To explore genes involved in epiblast development, we have employed whole genome microarray expression profiling as a discovery platform to identify genes. Embryoid body (EB) formation induces embryonic stem (ES) cells to differentiate into germ layers via epiblasts and extra-embryonic tissues, whereas ES cells give rise only to extra-embryonic tissues in monolayer culture. We compared gene expression profiles of ES cells in each differentiation culture methods at day 1-3 or 4 of differentiation. The expression of organizer related genes (Lhx1, Cer1 and Foxa2) was specifically induced at day 3 of EBs, but not in monolayer culture. In epiblast model cells, the overexpression of Lhx1 induced gene expression of organizer and meso-endodermal markers, suggested that Lhx1 was related to epiblast differentiation. Gene expression related epiblast development was measured at undifferentiated state and day 1-3 or 4 of differentiation. Two independent experiments were performed at each time using different people for each experiment.
Project description:Primitive ectoderm cells (PE) in blastocysts represent the foundation of the pluripotent state, which is lost progressively during development. For example, development of epiblast cells from PE in postimplantation embryos is accompanied by transcriptional and epigenetic changes, including DNA methylation and X inactivation (Refs); these changes alter the nature of epiblast cells fundamentally, affecting their responsiveness to signaling molecules, and constitute a robust boundary that prevents their reversion to a PE-like state. Notably, epiblast cells unlike PE, are refractory to leukaemia inhibitory factor (LIF)/STAT3 signalling in vitro; instead, they respond to FGF/Activin to form self-renewing epiblast stem cells (EpiSCs) that are like human ES cells, which differ significantly from mouse embryonic stem cells (ES) derived from PE. However, here we show that under appropriate conditions, epiblast cells from postimplantation embryos can respond to LIF/STAT3/fetal calf serum (FCS), and undergo reprogramming to form embryonic stem cell -like cells (repiES: reprogrammed epiblast ES-like cells). Reprogramming of epiblast cells occurs progressively. First, they form colonies that retain key properties of epiblast cells (cEpi: cultured epiblast), which subsequently show erasure of epigenetic modifications, including DNA demethylation and X-reactivation to generate repiES. Analysis also revealed that repiES progressively acquire a transcriptome profile of ES cells that is distinct from cEpi and EpiSCs. In chimeras, repiES contributed to all the tissues, including germ cells. Thus, we show for the first time that reversion of epiblast cells to repiES phenotype entails progressive loss of phenotypic and epigenetic memory of epiblast cells. Our study provides insights into underlying mechanisms, and a tractable model for how signaling molecules induce epigenetic reprogramming of cells leading to an elemental pluripotent state.