Fig. 2: Proliferation and differentiation potentials of hTSL cells.

a Growth curve of hTS and hTSL cells. Although hTS and hTSL^naïve cells could be stably maintained for more than 100 days, hTSL^primed cells stopped proliferation within 50 days. b Time-lapse analysis of EVT-like cells differentiating from hTS and hTSL cells. The phase-contrast images are taken from time-lapse Supplementary Movie 1–3. The scale bar indicates 300 μm. Similar results were obtained with two independent cell lines. c Flow cytometry analysis of HLA-G expression on EVT-like cells derived from hTS and hTSL^naïve cells. Representative data obtained from two independent cell lines are shown. d Phase contrast and immunofluorescence images of ST-like cells derived from hTS and hTSL cells. Cells were stained for SDC1 and CGB. Nuclei were stained with Hoechst 33258. The scale bar indicates 100 μm. Similar results were obtained with two independent cell lines. e Fusion efficiency of ST-hTS and -hTSL cells. The fusion index is defined as (N-S)/T, where N is the number of nuclei in the syncytia, S is the number of syncytia, and T is the total number of nuclei counted. Three ST-hTS, two ST-hTSL^naïve, and two ST-hTSL^primed cell lines were analyzed. Black bars and numbers indicate the mean fusion indexes. f Levels of hCG secreted by ST-hTS and -hTSL cells. Three ST-hTS, two ST-hTSL^naïve, and two ST-hTSL^primed cell lines were analyzed. Black bars and numbers indicate the mean amount of hCG.