Figure 4. Deferoxamine alters EPC mitochondrial bioenergetics and dynamics. (A) DFO altered the bioenergetic profiles of human EPCs. Representative OCR curves of the EPCs are shown after the sequential addition of mitochondrial inhibitors to acquire respiratory parameters. The OCRs were automatically calculated and recorded in real time using Seahorse XF-24 software. EPCs with or without four-day 3 μM DFO treatment were seeded in a non-CO2 incubator for one hour before the OCR assay. Respiratory inhibitors were injected at the indicated times (a, oligomycin; b, CCCP; c, antimycin A) to determine the proton leak respiration, maximal respiratory capacity and mitochondrial reserve capacity, respectively. (B) Quantitative comparison of the OCRs of EPCs in the control (CTRL, 0 μM) and DFO (3 μM) groups. Despite proton leak respiration and non-mitochondrial respiration, all the OCR parameters were significantly reduced in the DFO group. * P < 0.05, ** P < 0.01. (C) Western blots were mitochondrial proteins in EPCs with or without DFO treatment, and in young or old EPCs. (D) Quantification of Western blot images are from three independent experiments. Young EPCs were treated with DFO (3 μM) for four days. EPCs of the same clone as the young EPCs with 10 additional passages were defined as old EPCs. (E) ATP production rate in DFO-treated EPCs. ** P < 0.01 compared with the untreated group. The experiment was repeated with three different clones of EPCs with similar results.