Suppression of ERK signalling promotes pluripotent epiblast in the human blastocyst

Confocal microscopy images (.lif) of human embryos from the manuscript:<br>Simon et. al., (2025) Suppression of ERK signalling promotes pluripotent epiblast in the human blastocyst.<br>FGF experiments (related to Fig. 1a):<br>Experiments 220318, 220512, 220520, 220705, 241203, and 241223Control vs FGF (250ng/ml FGF4 + Heparin, 500ng/ml FGF4 + Heparin, and 750ng/ml FGF4 + Heparin) treated Day 5 human embryos for 36 hours.Immunofluorescence staining for GATA4 (A488, hypoblast), NANOG (A594, epiblast), and GATA3 (A647, trophectoderm) and counterstained with DAPI.Imaged on Leica SP8 Scanning Confocal Microscopy.pERK experiments (related to Fig. 2a):Experiments 211021, 211105 and 220120Control Day 5, Day 6 and Day 6.5 human embryosImmunofluorescence staining for SOX2 (A488, epiblast), pERK (A594) and OTX2 (A647, hypoblast) and counterstained with DAPI.Imaged on Leica SP8 Scanning Confocal Microscopy.ERKi experiments (related to Fig. 2d and 4a):Experiments 220205, 220225, and 220311Control (0.1% DMSO) vs ERKi (5μM Ulixertinib) treated Day 5 human embryos for 36 hours.Immunofluorescence staining for GATA4 (A488, hypoblast), NANOG (A594, epiblast), and GATA3 (A647, trophectoderm) and counterstained with DAPI.Imaged on Leica SP8 Scanning Confocal Microscopy.Experiment 231212Control (0.1% DMSO) vs ERKi (5μM Ulixertinib) treated Day 5 human embryos for 36 hours.Immunofluorescence staining for KLF17 (A488 - naive pluripotency), KLF4 (A555, failed), and SOX2 (A647, epiblast) and counterstained with DAPI.Imaged on Leica SP8 Scanning Confocal Microscopy.Please see manuscript for detailed materials and methods<br>Downstream quantification of fluorescence intensities performed with an image analysis pipeline available on GitLab: https://gitlab.developers.cam.ac.uk/ctr/ctr-bioinformatics/niakan-lab/simon-et-al-2025