Fig. 2: FGF signalling is required for proliferation during post-implantation development. | Nature Communications

Fig. 2: FGF signalling is required for proliferation during post-implantation development.

From: A single cell characterisation of human embryogenesis identifies pluripotency transitions and putative anterior hypoblast centre

Fig. 2

a/b UMAPs showing expression levels of main FGF ligands (FGF2/4) (a) and receptors (FGFR1/2/3/4) (b). The epiblast is a source of FGF2/4. FGF receptors (FGFR1/2/3/4) are widely expressed throughout all the lineages, with FGFR1 being the most highly expressed. c Immunofluorescence of human embryos at 8 d.p.f. cultured in DMSO control, in MEK inhibitor PD0325901 at 3 and 1 μM, in pan-FGFR inhibitor LY2874455 at 1 μM and 500 nM, in FGF2/4+heparan sulphate proteoglycans. On the left: zoom-out maximum projection, on the right z-sections. Number of experimental replicates: 9. d–f Quantification of the cell number for the epiblast marked by OCT4 (d), hypoblast by SOX17 expressing cells in contact with the basal side of epiblast (e), and trophoblast (negative for OCT4/SOX17) (f). Statistical test: two-tailed Kruskal–Wallis test with Dunn’s correction. d Inhibition by PD 3 μM causes significant reduction of OCT4 cells, non-significant at 1 μM: p = 0.0026 (**) control vs PD 3 μM. Inhibition by LY causes a significant reduction both at 1 μM and 500 nM: p = 0.0006 (***) control vs LY 1 μM, p = 0.0109 (*) control vs LY 500 nM. Non-significant difference when supplemented with FGF2/4. e Inhibition by PD causes a significant reduction of SOX17 cells both at 3 μM and 1 μM: p = 0.0023 (**) control vs PD 3 μM, p = 0.0203 (*) control vs PD 1 μM. Inhibition by LY causes a significant reduction both at 1 μM and 500 nM: p = 0.0011 (**) control vs LY 1 μM, p = 0.0002 (***) control vs LY 500 nM. Non-significant difference when supplemented with FGF2/4. f Inhibition by PD does not cause a significant reduction in trophoblast cells, either at 3 μM or 1 μM. Inhibition by LY causes significant reduction only at 500 nM: p = 0.0015 (**) control vs LY. Non-significant difference when supplemented with FGF2/4. Box represents the 25th–75th percentiles interval, middle line the median, cross represents the mean, whiskers show the minimum and maximum values, dots represent individual embryos. Number of embryos: control (n = 19), PD 3 μM (n = 12), PD 1 μM (n = 15), LY 1 μM (n = 8), LY 500 nM (n = 8), FGF2/4 (n = 7). Scale bars: 50 μm (Fig. 2c) and 25 μm (Fig. 2c i–ii, zoom). Source data are provided as a Source Data file.

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