Fig. 4

High-quality, functional RPE was obtained with the xeno-free differentiation method. a RT-PCR showing signature RPE gene expression, and b immunofluorescence labeling and c Western blot showing key RPE protein expression after final maturation on inserts for hESC1-RPE. Nuclei counterstained with DAPI; scale bars = 20 μm. d Confocal sections after 4 h POS feeding at +37 °C and at +4 °C (negative control; neg.contr.). Arrows indicate internalized POS labeled with anti-opsin antibody. Scale bars = 20 μm. e Mean PEDF secretion measured with ELISA from the apical side of cell culture inserts; n = number of inserts from two independent differentiation experiments. Error bars denote standard deviation. +/– ind. with and without induction, hPSC human pluripotent stem cell