Project description:Bivalent histone domains have been proposed to contribute to pluripotency in embryonic stem cells, suggesting an epigenetic mechanism may regulate stem cell behavior in general. Here we compare histone modifications in two other stem cells derived from the blastocyst. We show that extraembryonic stem cells have little repressive lysine 27 trimethylation and few bivalent domains. Thus, bivalent domains are not a common mechanism for maintaining the undifferentiated state in blastocyst-derived stem cells and alternative mechanisms must mediate transcriptional repression in extraembryonic cells. We show that lysine 9 trimethylation, but not DNA methylation, is likely to fulfill this role. Intriguingly, although we do detect bivalent domains in pluripotent cells in the early mouse embryo, the epigenetic status of extraembryonic cells does not entirely reflect their in vitro stem cell counterparts. Therefore, differences in epigenetic regulation between lineage progenitors in vivo and in vitro may arise during selection for self-renewal in vitro. Expression profiles [GSM388878-GSM388881] of three different stem cells (R1 embryonic stem cells, trophoblast stem cells, extraembryonic endoderm stem cells) were generated for comparison to CHIP-seq data [GSM392044-GSM392055] of the same three stem cell lines to observe correlations with Histone 3 K4 and K27 trimethylation patterns. CHIP-seq details: R1 embryonic stem cells, trophoblast stem cells or extraembryonic endoderm stem cells were grown, lysed and chromatin purified. The chromatin was immunoprecipitated for either histone 3 K4 trimethylation or histone 3 K27 trimethylation and the immunoprecipitate was subjected to purification and high-throughput Illumina-based sequencing.
Project description:Faithful embryogenesis requires the precise coordination between embryonic and extraembryonic tissues. Although embryonic and extraembryonic stem cells have been derived from several mammalian species including humans, they are cultured in different conditions, which makes it difficult to study their intercommunication. Here, by simultaneously activating FGF, TGF-β and WNT pathways, we derived stable pluripotent stem cells (PSCs), trophoblast stem cells (TSCs) and extraembryonic endoderm stem cells (XENs) from mouse blastocysts under the same condition (FTW). Co-culture of PSCs and XENs in the same environment uncovered, among other interactions, a previously unrecognized control of proliferation of epiblast cells by extraembryonic endoderm cells. FTW condition also supported de novo derivation of XENs from cynomolgus monkey and human blastocysts, and enabled setting up co-culture of human iPSCs and XENs. Crosspieces comparison revealed conserved and divergent processes and genes regulating XENs and ligand-receptor interactions between pluripotent and extraembryonic endoderm cells. Our study establishes a unique stem cell co-culture strategy to examine embryonic and extraembryonic lineage crosstalk during early mammalian development, and opens the door for developing more faithful in vitro models and differentiation protocols.
Project description:Faithful embryogenesis requires the precise coordination between embryonic and extraembryonic tissues. Although embryonic and extraembryonic stem cells have been derived from several mammalian species including humans, they are cultured in different conditions, which makes it difficult to study their intercommunication. Here, by simultaneously activating FGF, TGF-β and WNT pathways, we derived stable pluripotent stem cells (PSCs), trophoblast stem cells (TSCs) and extraembryonic endoderm stem cells (XENs) from mouse blastocysts under the same condition (FTW). Co-culture of PSCs and XENs in the same environment uncovered, among other interactions, a previously unrecognized control of proliferation of epiblast cells by extraembryonic endoderm cells. FTW condition also supported de novo derivation of XENs from cynomolgus monkey and human blastocysts, and enabled setting up co-culture of human iPSCs and XENs. Crosspieces comparison revealed conserved and divergent processes and genes regulating XENs and ligand-receptor interactions between pluripotent and extraembryonic endoderm cells. Our study establishes a unique stem cell co-culture strategy to examine embryonic and extraembryonic lineage crosstalk during early mammalian development, and opens the door for developing more faithful in vitro models and differentiation protocols.
Project description:To identify splicing regulators with unique regulation in placenta and the trophectoderm lineage, we sequenced trophoblast stem (TS) and Extraembryonic endoderm stem (XEN) cells.
Project description:A blastocyst consists of three distinctive cell types: epiblast (EPI), trophoblast (TB), and primitive endoderm (PrE). Stem cell lines representing EPI and TB (embryonic stem (ES) cells and trophoblast stem (TS) cells) have been derived and they contribute to epiblast derivatives and trophoblast derivatives of stem cell-blastocyst chimeras, respectively. Although derived from PrE, extraembryonic endoderm (XEN) cells contribute to only a limited part of parietal endoderm (PE) but rarely to other PrE derivatives. Here we describe the establishment of primitive endoderm stem (PrES) cell lines in mice. PrES cells were derived and maintained in a serum-free media containing CHIR99021, FGF4, heparin, and PDGF-AA. RNA-seq analysis revealed that the transcriptome of PrES cells is globaly different from XEN cells: PrES cells express not only endoderm markers (Dab2, Gata4, Gata6, Sox17, etc.), but also pluripotent markers (Pou5f1, Cdh1, Nanog, Zfp42, etc.), and resembles in vivo founder PrE. PrES cells were rapidly and efficiently incorporated into PrE after blastocyst injection and efficiently contributed to all PrE derivatives, including PE, VE (visceral endoderm), and MZE (marginal zone endoderm) in chimeras. Importantly, PrES cells rescued embryonic lethality of PrE-depleted blastocysts by complementing all PrE derivatives. PrES cells thus not only contribute to understanding of the mechanisms of PrE specification but also provide a critical resource for artificial embryo reconstitution by stem cells alone.
Project description:The conventional trophoblast stem cells represent post-implantation extraembryonic ectoderm-like state and not that of pre-implantation trophectoderm, irrespective of their origin. To capture the trophectoderm-like state we established culture conditions that facilitate the co-existence of characteristics of both the extraembryonic lineages, namely, primitive endoderm and trophectoderm. We term these cells XTE cells. We carried out RNA-seq on XTE cells from different origins, as well as XEN cells, XEN-like cells, and ES cells, to assess their transcriptional profiles and identify putative marker genes and master regulators.
Project description:The mammalian blastocyst consists of three distinct cell types: epiblast, trophoblast (TB), and primitive endoderm (PrE). Although embryonic stem cells (ESCs) and trophoblast stem cells (TSCs) retain the functional properties of Epi and TB, the currently available extraembryonic endoderm cells (XENC) do not fully recapitulate the developmental potential of PrE. Here we report derivation of primitive endoderm stem cells (PrESCs) in mice. PrESCs express both PrE and pluripotency marker genes like founder PrE. These cells are efficiently incorporated into PrE upon blastocyst injection, generate functionally competent PrE-derived tissues, and support fetal development of PrE-depleted blastocysts in chimeras. Establishment of PrESCs therefore represents a significant step-forward in elucidating the mechanisms for PrE specification and subsequent pre- and post-implantation development.
Project description:DNA and Histone-3 Lysine 27 methylation typically function as repressive modifications and operate within distinct genomic compartments. In mammals, the majority of the genome is kept in a DNA methylated state, whereas the Polycomb Repressive Complexes regulate the unmethylated CpG-rich promoters of developmental genes. In contrast to this general framework, the extraembryonic lineages display non-canonical, globally intermediate DNA methylation levels that includes disruption of local Polycomb domains. To better understand this unusual landscape’s molecular properties, we genetically and chemically perturbed major epigenetic pathways in mouse Trophoblast Stem Cells (TSCs). We find that the extraembryonic epigenome reflects ongoing and dynamic de novo methyltransferase recruitment, which is continuously antagonized by Polycomb to maintain intermediate, locally disordered methylation. Despite its disorganized molecular appearance, our data point to a highly controlled equilibrium between counteracting repressors within extraembryonic cells, one that can seemingly persist indefinitely without bistable features typically seen for embryonic forms of epigenetic regulation. Dataset 1: EED co-immunoprecipitation of wild type mouse trophoblast stem cells (TSCs) and Eed knockout TSCs as control, with 3 biological replicates per condition.
Project description:Embryonic (ES) and epiblast (EpiSC) stem cells are pluripotent but committed to an embryonic lineage fate. Conversely, trophoblast (TS) a nd extraembryonic endoderm (XEN) stem cells contribute predominantly to tissues of the placenta and yolk sac, respectively. Here we show that each of these four stem cell types is defined by a unique DNA methylation profile. Despite their distinct developmental origin, TS and XEN cells share key epigenomic hallmarks, chiefly characterized by robust DNA methylation of embryo-specific developmental regulators, as well as a subordinate role of 5-hydroxymethylation. We also observe a substantial methylation reinforcement of pre-existing epigenetic repressive marks that specifically occurs in extraembryonic stem cells compared to in vivo tissue, presumably due to continued high Dnmt3b expression levels. These differences establish a major epigenetic barrier between the embryonic and extraembryonic stem cell types. In addition, epigenetic lineage boundaries also separate the two extraembryonic stem cell types by mutual repression of key lineage-specific transcription factors. Thus, global DNA methylation patterns are a defining feature of each stem cell type that underpin lineage commitment and differentiative potency of early embryo-derived stem cells. Our detailed methylation profiles identify a cohort of developmentally regulated sequence elements, such as orphan CpG islands, that will be most valuable to uncover novel transcriptional regulators and pivotal M-^QM-^QgatekeeperM-^RM-^R genes in pluripotency and lineage differentiation.