Differential response of epiblast stem cells to Nodal and Activin signalling: a paradigm of early endoderm development in the embryo

Abstract

Mouse epiblast stem cells (EpiSCs) display temporal differences in the upregulation of Mixl1 expression during the initial steps of in vitro differentiation, which can be correlated with their propensity for endoderm differentiation. EpiSCs that upregulated Mixl1 rapidly during differentiation responded robustly to both Activin A and Nodal in generating foregut endoderm and precursors of pancreatic and hepatic tissues. By contrast, EpiSCs that delayed Mixl1 upregulation responded less effectively to Nodal and showed an overall suboptimal outcome of directed differentiation. The enhancement in endoderm potency in Mixl1-early cells may be accounted for by a rapid exit from the progenitor state and the efficient response to the induction of differentiation by Nodal. EpiSCs that readily differentiate into the endoderm cells are marked by a distinctive expression fingerprint of transforming growth factor (TGF)-β signalling pathway genes and genes related to the endoderm lineage. Nodal appears to elicit responses that are associated with transition to a mesenchymal phenotype, whereas Activin A promotes gene expression associated with maintenance of an epithelial phenotype. We postulate that the formation of definitive endoderm (DE) in embryoid bodies follows a similar process to germ layer formation from the epiblast, requiring an initial de-epithelialization event and subsequent re-epithelialization. Our results show that priming EpiSCs with the appropriate form of TGF-β signalling at the formative phase of endoderm differentiation impacts on the further progression into mature DE-derived lineages, and that this is influenced by the initial characteristics of the cell population. Our study also highlights that Activin A, which is commonly used as an in vitro surrogate for Nodal in differentiation protocols, does not elicit the same downstream effects as Nodal, and therefore may not effectively mimic events that take place in the mouse embryo.

Spatial Transcriptome for the Molecular Annotation of Lineage Fates and Cell Identity in Mid-gastrula Mouse Embryo

“…We further applied zip code mapping to identify the epiblast cells that are developmentally similar to the epiblast stem cells (EpiSCs). In agreement with our previous finding that EpiSCs are congruent with the anterior primitive streak cells of the midgastrulation embryo (Kaufman-Francis et al, 2014;Kojima et al, 2014a), cells of ten embryo-derived EpiSC lines and one ES cell-derived EpiSC line (ESD-EpiSC) (Zhang et al, 2010) were mapped to epiblast cell populations that encompassed those in the distal posterior domains (1P-4P) (Figures 7H, i-iii and 1F). Interestingly, EpiSCs with enhanced mesendoderm propensity displayed the transcriptome characteristics more of the posterior epiblast (the presumptive mesoderm and endoderm progenitors in the anterior primitive streak, Figure 7H iii; cf.…”

Mapping a Circular RNA–microRNA–mRNA-Signaling Regulatory Axis that Modulates Stemness Properties of Cancer Stem Cell Populations in Colorectal Cancer Spheroid Cells

“…The six core mRNAs have, indeed, also previously been reported to be involved in diverse CSC-related properties, ranging from proliferation, migration and invasion, chemoresistance and tumorigenicity (see Table 4 for full references). Importantly, pluripotency-associated properties have also been demonstrated in other reports [69][70][71][72][73]. The six core mRNAs may further be implicated to be linked with four major signaling pathways that modulate numerous CSC-associated properties observed in the CRC spheroids ( Figure 6).…”

A Case for Revisiting Nodal Signaling in Human Pluripotent Stem Cells

“…There have been reports of differing biological activity of Activin and Nodal. Chen et al found that the quality of endoderm induced by activin differed from that induced by NODAL, 76 and Tam and coworkers 77 showed that epiblast stem cells respond differently to activin compared to NODAL. As noted above, even in the presence of high doses of Activin or TGF‐β under defined conditions, hPSCs still display neural lineage priming across most of the population, suggesting that the suppression of neural specification mediated by Nodal signaling is incomplete under these conditions.…”