Figure 7: BLVRB and HMOX1 Are Induced in Macrophages on Iron Exposure

THP-1 human monocytic cell line–derived human macrophages were stimulated with ferric ammonium citrate (FAC) and cellular iron uptake quantified over time using the ferrozine assay (top panel). qPCR shows a rapid induction of HMOX1 expression already after 4 h of stimulation, whereas BLVRB was up-regulated after 24 h. Plots show mean fold change ± SEM of 3 independent experiments. p values calculated with analysis of variance (ANOVA) across all groups and Student's t-test in comparison to 2 h time point. All results normalized to the nonstimulated control cells (A). Perls staining confirms presence of cellular iron deposits after 24 h of stimulation. By immunofluorescence, BLVRB protein is induced and localized to subcellular vesicles in FAC-treated cells, whereas HMOX1 shows perinuclear and diffused cytoplasmic localization (arrows). Bottom panels show higher magnification (B). DAPI = 4,6-diamino-phenylindole; other abbreviations as in Figures 1, 2, and 5.