Fig. 4
POS phagocytosis and the role of Nav1.4 and Nav1.8. a Phagocytosis was studied by dissecting mouse eyes at various time points during the circadian cycle. Filamentous actin was stained with phalloidin (gray in the merged image) to highlight epithelial cell–cell junctions. Laser scanning confocal microscopy Z-maximum intensity projections of mouse RPE prepared at light onset showed localization of opsin labeled POS particles (blue) and Nav1.4 (green) together with Nav1.8 (red). Lower panels show a high contrast blowup of highlighted regions. Scale bars 10 μm. To study phagocytosis in vitro, mature hESC-derived RPE were labeled with 1.4 nm nanogold-conjugated antibodies against b Nav1.4 and c Nav1.8 during phagocytosis of purified porcine POS particles and in control conditions. Without POS exposure, both channels showed localization near the cell-cell junctions (black arrows) but by incubating the monolayers with POS particles for b 2 h or c 4 h, the localization (black arrows) was also evident around the phagocytic cups and recently ingested phagosomes. Scale bars 250 nm