Fig. 1

Differentiation of human induced pluripotent stem cell (hiPSC)-derived endothelial cells (iECs) from wild type (WT) and fibrodysplasia ossificans progressiva (FOP) hiPSC lines. a Endothelial cell differentiation protocol adapted from White et al. [17]. WT and FOP hiPSCs were induced to form mesodermal progenitors using BMP4, Activin A, and bFGF. Embryoid bodies (EBs) were cultured in medium supplemented with VEGF and bFGF on day 4 and plated onto collagen IV on day 5. iEC precursors were identified by KDR/PECAM positivity. Scale bars, 200 μm (hiPSCs, EBs, and EBs at day 6) and 1 μm (hiPS-derived endothelial cells). b Mean percentage of cells expressing both PECAM and KDR by fluorescence-activated cell sorting (FACS) analysis on day 6 of endothelial differentiation of one WT hESC line, three WT hiPSC lines, and four FOP hiPSC lines. Error bars represent the mean ± one standard deviation of at least three independent replicates for each of the three WT and four FOP cell lines. Mean values were not statistically different. c FACS analysis of WT and FOP hiPSCs on day 0 and day 6 of endothelial differentiation. iECs co-expressing PECAM and KDR were sorted by FACS on day 6 and then cultured in endothelial cell medium. Analysis of PECAM and VE-Cadherin expression by FACS of sorted iECs after one passage is shown on the right. d WT and FOP hiPSCs were differentiated as in Fig. 1A and sorted on day 6. iECs were immunostained for endothelial markers PECAM and VE-Cadherin. Scale bars, 100 μm