FX is internalized by SR-AI in HEK293 cells but not in THP1-derived macrophages. THP1-derived macrophages (A,C) or SR-AI–expressing HEK-293 (B,D) were incubated with FX for 1 hour at 37°C. FX was immunostained (red) along with polymerized actin counterstaining using Alexa488-labeled phalloïdin (A-B) or EEA-1 immunostaining (C-D). Dotted lines define cell boundaries based on phalloïdin staining (A-B), and arrows indicate spots of colocalization (C-D). Images were acquired in confocal microscopy (objective 63×, z-depth 1 µm). Bars represent 10 µm. (E) FX colocalization with EEA-1 was quantified by calculating the tMC for FX using JACoP plugin in Fiji software. The results are expressed in a whisker plot where boxes represent the median and 25th to 75th percentile and bars represent the minimum and maximum of 10 to 11 cells in 3 different experiments. ***P < .001 in a Mann-Whitney nonparametric unpaired statistical test.