Fig. 2: Change in cell morphology during differentiation of iPSCs into iMSC ARG.

Top row (Day 4): tight cell–cell contacts, typical for densely packed pluripotent stem cell colonies, are completely lost in cells undergoing ARG differentiation protocol, whereas the fibroblast-like cells undergoing differentiation are mixed with seemingly intact pluripotent stem cell colonies (yellow arrowheads) in cell cultures undergoing TEX differentiation protocol. Middle row (Day 12): appearance of large flattened cells indicated cellular senescence-like features (yellow arrows) in cells undergoing ARG differentiation protocol. In contrast, all differentiating iPSC12 and iPSC13 have uniform fibroblast-like morphology. Bottom row: iMSCs growing on tissue culture-treated plastic. Senescent-like cells (yellow arrows) are present only in cell cultures undergoing ARG-differentiation protocol