Figure 4. MSCs enhance macrophage bioenergetics.

(a) Mitochondrial respiration of human macrophages, human MSCs or human fibroblasts was measured as OCR using the XF technology. Macrophages were co-cultured with or without human MSCs or fibroblasts (1:10 ratio) or treated with human MSC-derived exosomes (40 μg per protein) in the presence or absence of Oligomycin A and FCCP to differentiate ATP-linked respiration from the proton leak. Plotted data (mean±s.e.m.) were performed using six replicates per sample and repeated three times. (b) Pseudocoloured photomicrographs (0–240 min) of MitoSOX Red-stained macrophages that were non-stimulated (upper panel), or treated with silica (20 μg cm⁻², lower panel) or silica plus human MSC-derived exosomes (added 10 min after silica, middle panel). Scale bars, 50 μ. (c) Time course of MitoSOX Red emission by human macrophages treated as in b. Figure is representative of five exposures (nine stages positions per test and 6 cells per stage). (d) OCR as in a of silica-exposed macrophages treated with or without human MSCs, human MSC-derived exosomes or human fibroblasts. Plotted values (mean±s.e.m.) are from experiments repeated three times, *P<0.05 as compared to control, ^#P<0.05 as compared to silica treated macrophages, as determined by Student's t-test.