Figure 3.

NaIO₃ induces release of ferritin in lysosomal membrane-enclosed vesicles. Co-immunostaining of ARPE-19 cells with goat anti-ferritin and rabbit anti-LAMP-1 antibodies followed by species-specific secondary antibodies conjugated with Alexa Fluor 546 (red) and Alexa Fluor 488 (green) showed co-localization in intracellular (panels 7, 8, arrowhead) and extracellular (panels 7, 8 vs. panels 3, 4, arrowhead) vesicles in NaIO₃-treated cells relative to controls. Extracellular vesicles positive for LAMP-1 were also seen in vehicle-treated controls (panels 3, 4, arrowhead). Cells treated with only secondary antibodies showed no reaction (Supplementary Figure S2). Experiments shown in Figure 2E and Figure 3 were conducted simultaneously to maintain scientific rigor and had the same controls. Scale bar: 25 µm.