Abstract
Cell fate commitment of pre-implantation blastocysts, to either the inner cell mass or trophoblast, is the first step in cell lineage segregation of the developing human embryo. However, the intercellular signals that control fate determination of these cells remain obscure. Human embryonic stem cells (hESCs) provide a unique model for studying human early embryonic development. We have previously shown that Activin/Nodal signaling contributes to maintaining pluripotency of hESCs, which are derivatives of the inner cell mass. Here we further demonstrate that the inhibition of Activin/Nodal signaling results in the loss of hESC pluripotency and trophoblast differentiation, similar to BMP4-induced trophoblast differentiation from hESCs. We also show that the trophoblast induction effect of BMP4 correlates with and depends on the inhibition of Activin/Nodal signaling. However, the activation of BMP signaling is still required for trophoblast differentiation when Activin/Nodal signaling is inhibited. These data reveal that the early lineage segregation of hESCs is determined by the combinatorial signals of Activin/Nodal and BMP.
Highlights
The pre-implantation human blastocyst consists of two cell types: the pluripotent inner cell mass and the trophoblast, or the outer epithelial layer of the blastocyst
Inhibition of Activin/Nodal Signaling in human embryonic stem cell (hESC) Results in Rapid Differentiation—Activin/Nodal signaling has been shown to play a key role in the maintenance of undifferentiated human ES cells (16 –18)
To further address the function of Activin/Nodal signaling in the developmental fate of hESCs, and to understand the early developmental mechanisms of human embryogenesis, we inhibited Activin/Nodal signaling in hESCs
Summary
All hESC experiments were conducted in accordance with the guidelines for research on human embryonic stem cells, jointly issued by the Ministry of Science and Technology and the Ministry of Health of China [20], and approved by the ethical committee of Shanghai Institutes for Biological Sciences. Protein factors or SB431542 were added directly to the culture in the continued presence of conditioned medium (CM). Real-time PCR was performed using a Synergy Brand GreenIbased PCR Master mixture (TOYOBO). The normalized expression values for all control and treated samples were averaged, and an average -fold change was determined. Analysis of variance was conducted between the normalized relative expression values for control and treated samples to determine statistical significance. The following antibodies were used: anti-SSEA4 (Developmental Studies Hybridoma Bank), anti-hCG␣ (R&D Systems), and anti-hCG (Abcam). The concentration of estradiol and progesterone were analyzed with an ELISA kit
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
