Project description:XEN cells are derived from the primitive endoderm of mouse blastocysts. In culture and in chimeras they exhibit properties of parietal endoderm. However, BMP signaling promotes XEN cells to form an epithelium and differentiate into visceral endoderm (VE). Of the several different subtypes of VE described, BMP induces a subtype that is most similar to the VE adjacent to the trophoblast-derived extraembryonic ectoderm. The experiment was performed to gain insight into genes regulated by BMP and activin in XEN cells, and also to more precisely define the VE subtypes formed in culture. IM8A1 XEN cells were treated for 6 days with BMP2 (20 ng/ml, R&D Systems), activin A (30 ng/ml, Peprotech), both, or neither in GMEM + 10% fetal bovine serum.
Project description:XEN cells are derived from the primitive endoderm of mouse blastocysts. In culture and in chimeras they exhibit properties of parietal endoderm. However, BMP signaling promotes XEN cells to form an epithelium and differentiate into visceral endoderm (VE). Of the several different subtypes of VE described, BMP induces a subtype that is most similar to the VE adjacent to the trophoblast-derived extraembryonic ectoderm. The experiment was performed to gain insight into genes regulated by BMP and activin in XEN cells, and also to more precisely define the VE subtypes formed in culture.
Project description:The signaling pathway for Nodal, a ligand of the transforming growth factor-beta (TGF-beta) superfamily, plays a central role in regulating the maintenance and/or differentiation of stem cell types that can be derived from the peri-implantation mouse embryo. Extraembryonic endoderm stem (XEN) cells are derived from the primitive endoderm of the blastocyst, which normally gives rise to the parietal and the visceral endoderm in vivo, but XEN cells do not contribute efficiently to the visceral endoderm in chimeric embryos. We have found that treatment of XEN cells with Nodal and/or Cripto, an EGF-CFC co-receptor for Nodal, results in up-regulation of markers for visceral endoderm as well as anterior visceral endoderm (AVE). Re-introduction of treated XEN cells into chimeric embryos by blastocyst injection or morula aggregation results in contribution to visceral endoderm and AVE. In culture, XEN cells do not express Cripto, but do express the related EGF-CFC co-receptor Cryptic and require Cryptic for Nodal signaling. Notably, the response to Nodal can be blocked by treatment with the ALK4/ALK5/ALK7 inhibitor SB431542, but Cripto treatment is unaffected, suggesting that its activity is independent of type I activin receptors. Gene set enrichment analysis of genome-wide expression signatures generated from XEN cells under these treatment conditions confirms the differing responses of Nodal- and Cripto-treated XEN cells to SB431542. Our findings define distinct pathways for Nodal and Cripto in the differentiation of visceral endoderm and AVE from XEN cells, and provide new insights into the specification of these cell types in vivo. Murine Xen-eyfg cell line treated with Alk4 inhibitor SB431542, Nodal and Cripto recombinant proteins.
Project description:The signaling pathway for Nodal, a ligand of the transforming growth factor-beta (TGF-beta) superfamily, plays a central role in regulating the maintenance and/or differentiation of stem cell types that can be derived from the peri-implantation mouse embryo. Extraembryonic endoderm stem (XEN) cells are derived from the primitive endoderm of the blastocyst, which normally gives rise to the parietal and the visceral endoderm in vivo, but XEN cells do not contribute efficiently to the visceral endoderm in chimeric embryos. We have found that treatment of XEN cells with Nodal and/or Cripto, an EGF-CFC co-receptor for Nodal, results in up-regulation of markers for visceral endoderm as well as anterior visceral endoderm (AVE). Re-introduction of treated XEN cells into chimeric embryos by blastocyst injection or morula aggregation results in contribution to visceral endoderm and AVE. In culture, XEN cells do not express Cripto, but do express the related EGF-CFC co-receptor Cryptic and require Cryptic for Nodal signaling. Notably, the response to Nodal can be blocked by treatment with the ALK4/ALK5/ALK7 inhibitor SB431542, but Cripto treatment is unaffected, suggesting that its activity is independent of type I activin receptors. Gene set enrichment analysis of genome-wide expression signatures generated from XEN cells under these treatment conditions confirms the differing responses of Nodal- and Cripto-treated XEN cells to SB431542. Our findings define distinct pathways for Nodal and Cripto in the differentiation of visceral endoderm and AVE from XEN cells, and provide new insights into the specification of these cell types in vivo.
Project description:The visceral endoderm (VE) is an epithelial tissue in the early postimplantation mouse embryo that encapsulates the pluripotent epiblast distally and the extraembryonic ectoderm proximally. In addition to facilitating nutrient exchange before the establishment of a circulation, the VE is critical for patterning the epiblast. Since VE is derived from the primitive endoderm (PrE) of the blastocyst, and PrE-derived eXtraembryonic ENdoderm (XEN) cells can be propagated in vitro, XEN cells should provide an important tool for identifying factors that direct VE differentiation. In this study, we demonstrated that BMP4 signalling induces the formation of a polarized epithelium in XEN cells. This morphological transition was reversible, and was associated with the acquisition of a molecular signature comparable to extraembryonic (ex) VE. Resembling exVE which will form the endoderm of the visceral yolk sac, BMP4-treated XEN cells regulated hematopoiesis by stimulating the expansion of primitive erythroid progenitors. We also observed that LIF exerted an antagonistic effect on BMP4-induced XEN cell differentiation, thereby impacting the extrinsic conditions used for the isolation and maintenance of XEN cells in an undifferentiated state. Taken together, our data suggest that XEN cells can be differentiated towards an exVE identity upon BMP4 stimulation, and therefore represent a valuable tool for investigating PrE lineage differentiation. Total RNA isolated in triplicate from XEN stem cell cultures that were untreated (samples 1-3) or treated with BMP4 growth factor (samples 4-6). Total RNA isolated in triplicate from XEN stem cells that were treated with BMP4 and were flow sorted as Afp::GFP-positive (samples 7-9) or Afp::GFP-negative (samples 10-12).
Project description:The visceral endoderm (VE) is an epithelial tissue in the early postimplantation mouse embryo that encapsulates the pluripotent epiblast distally and the extraembryonic ectoderm proximally. In addition to facilitating nutrient exchange before the establishment of a circulation, the VE is critical for patterning the epiblast. Since VE is derived from the primitive endoderm (PrE) of the blastocyst, and PrE-derived eXtraembryonic ENdoderm (XEN) cells can be propagated in vitro, XEN cells should provide an important tool for identifying factors that direct VE differentiation. In this study, we demonstrated that BMP4 signalling induces the formation of a polarized epithelium in XEN cells. This morphological transition was reversible, and was associated with the acquisition of a molecular signature comparable to extraembryonic (ex) VE. Resembling exVE which will form the endoderm of the visceral yolk sac, BMP4-treated XEN cells regulated hematopoiesis by stimulating the expansion of primitive erythroid progenitors. We also observed that LIF exerted an antagonistic effect on BMP4-induced XEN cell differentiation, thereby impacting the extrinsic conditions used for the isolation and maintenance of XEN cells in an undifferentiated state. Taken together, our data suggest that XEN cells can be differentiated towards an exVE identity upon BMP4 stimulation, and therefore represent a valuable tool for investigating PrE lineage differentiation.
Project description:In this study we showed that rat XEN cells grown in the presence of a GSK3 inhibitor exhibited enhanced formation of cell contacts and decreased motility. In contrast, treatment with forskolin induced the PE formation and epithelial-mesenchymal transition (EMT) in rat XEN cells. Using microarray and real-time PCR assays, we found that VE versus PE formation of rat XEN cells was correlated with change in expression levels of VE or PE marker genes. Similar to forskolin, EMT was prompted upon treatment of rat XEN cells with recombinant parathyroid hormone related peptide (PTHRP), an activator of the cAMP pathway in vivo. Taken together, our data suggest that rat XEN cells are PrE-like cells. The activation of Wnt pathway in rat XEN cells leads to the acquisition of VE characteristics, whereas the activation of the PTHRP/cAMP pathway leads to EMT and the formation of PE.
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:In this study we showed that rat XEN cells grown in the presence of a GSK3 inhibitor exhibited enhanced formation of cell contacts and decreased motility. In contrast, treatment with forskolin induced the PE formation and epithelial-mesenchymal transition (EMT) in rat XEN cells. Using microarray and real-time PCR assays, we found that VE versus PE formation of rat XEN cells was correlated with change in expression levels of VE or PE marker genes. Similar to forskolin, EMT was prompted upon treatment of rat XEN cells with recombinant parathyroid hormone related peptide (PTHRP), an activator of the cAMP pathway in vivo. Taken together, our data suggest that rat XEN cells are PrE-like cells. The activation of Wnt pathway in rat XEN cells leads to the acquisition of VE characteristics, whereas the activation of the PTHRP/cAMP pathway leads to EMT and the formation of PE. Rat XEN cells were cultured in four different conditions with 3 parallels for each condition: (1-3) without treatments control, (4-6) 2 days treated with CHIR alone, (7-9) 1 day treated with CHIR and 1 day with both CHIR and forskolin, and (10-12) 1 day treated with forskolin alone. In all samples on DAY1 cells were plated, at DAY2 cells were cultured in usual conditions (DMEM F12 medium and 10% Fetal Bovine Serum, both from Sigma) and inhibitor of GSK3 kinase 3 μM CHIR99021 (Axon Medchem) was added in samples 4-9. On DAY3 all cells were cultured in medium with 0.1% serum to exclude the influence of serum and in CONTROL (1-3) cells were cultured without experimental treatments, in CHIR (4-6) cells were further cultured with 3 μM CHIR99021, in CHIR plus FORSKOLIN cells were cultured with 3 μM CHIR99021 and 10μM Forskolin (Sigma), in FORSKOLIN cells were cultured for 1 day with 10 μM Forskolin. On DAY4 RNA was isolated.