📢 Save the date! I am excited to announce the International Dutch Embryo Model Meeting 2025 in Nijmegen (NL) on Thursday 27 March and Friday 28 March! Registration is open now, or more information: https://t.co/NnmKmuxjlC. Direct link to registration https://t.co/E6UVyxVpHA.

We are really excited to share our findings on monochorionic twinning in human blastoid embryo models https://t.co/6VUCshmitj, shedding light, finally, on the formation of identical twins. @MERLN_UM @Dorian_Luijkx https://t.co/x9jzpYjhci

Excited to share our latest work "Automated, high-throughput phenotypic screening and analysis platform to study pre- and post-implantation morphogenesis in stem cell-derived embryo-like structures"! https://t.co/063MD9upNB

Wanneer begint het leven van een stamcel-embryo? https://t.co/L3Q9ZA0lxv Een blogje n.a.v. van een experiment waarbij uit stamcellen gekweekte embryo's van java-aapjes zijn teruggeplaatst bij draagmoeders. Hierover schreef ik ook een artikel in het @ndnl

9. specification that is currently not exploited by the blastocyst.

8. differentiation potential seen with the addition of RA, although our data show that RA alone is not sufficient to robustly trigger PrE differentiation (Fig. 1L). An alternative explanation is that the induction cocktail may enforce ESCs to follow a route towards PrE

7. presence of a subset (<1%) of cells with higher developmental potential (e.g. 2-cell-like-cells (2CLC)(Macfarlan et al. 2012)). Recently, retinoic acid signalling was found as a potent inducer of these 2CLC in mESC (Iturbide et al. 2021). This could explain the increased XEnd

6. ICM precursor, it could be argued whether sufficient plasticity is still present in these cells to efficiently form PrE. Alternatively, the capacity of naive ESCs to form PrE-like cells might be due to a previously underestimated plasticity of these cells and/or to the

5. and RARγ. Thus, Epi cells and ESCs may use RA signals for development. However, since ESCs grown in 2i/lif conditions correspond transcriptionally to the E4.5 preimplantation Epi (Boroviak et al. 2014), the stage at which the Epi and PrE already bifurcated from their common

4. Retinoic Acid Receptor (RAR) isoforms RARα, RARβ and RARγ. Of these, RARα and RARγ are expressed from around the E3.5 blastocyst stage (Mohammed et al. 2017). Correspondingly, in our single cell RNA data we find that a subpopulation of ESCs expanded in 2i/lif expresses RARα

3. concentrations of retinoic acid in combination with serum-based medium is reported to be sufficient to drive PrE differentiation (Cho et al. 2012; Semrau et al. 2017). Retinoic acid is thought to trigger differentiation mainly by binding to the three partially redundant

2. Wigger et al. 2017; Chazaud et al. 2006; Yamanaka, Lanner, and Rossant 2010; Wicklow et al. 2014)). In addition, Wnt signalling has previously been identified for its role in PrE differentiation in ESCs (Toyokuni et al. 2018; Ohinata et al. 2022; Anderson et al. 2017), and low

1. FGF/Mapk/Erk signaling has been described extensively for its role in establishing the PrE/Epi proportion and reinforcing PrE identity ((Azami et al. 2017; Kang, Garg, and Hadjantonakis 2017; Molotkov et al. 2017; Ohnishi et al. 2014; Krawchuk et al. 2013; Schröter et al. 2015

We added a section in the discussion about this but it could not be added in the final manuscript due to size/length limitations. Here it is:

A thought: The findings of reprogramming mESC towards a totipotent state by using a combination of a GSKbeta inhibitor, a retinoic acid analogue and the compound WS6 may suggest the XEn/Epi co-induction happens via partial reprogramming

Happy to share our manuscript on the self-organized reciprocal inductions between the co-developing epiblast and extraembryonic endoderm tissues that support post-implantation progression @NRivron @MERLN_UM https://t.co/jgm33TxwYH

Impressive art on a wall in Valencia

Hubrecht and @MERLN_UM scientists have successfully created embryo-like structures from mouse #stemcells. This new method opens the door to understanding the first and hidden processes of life, problems of #infertility, or the embryonic origin of diseases. https://t.co/Vavz3dLl3e

Damage repair! How do they do it? Follow our cells! #cells #science #art

Dear Feras, The image of the ossicles is amazing! We'd like to publish it. Please contact me: erikvrij at gmail @Feras_lahham