Fig. 4

Pulmonary macrophages phagocytosed exMt. (A) The confocal laser scanning microscope micrographs show that the exMt labeled with MitoTracker are internalized by macrophages (white arrow, scale bars:100 μm, MitoTracker Deep Red: red, CD68: green, DAPI: blue). (B) Amnis^® flow cytometric images show exMt binding a macrophage (top panel), endocytosed by a macrophage (bottom panel), after 30 min co-incubation at 37 °C (representative images from 20,000 images randomly selected), as shown by a representative histogram in a concentration-dependent manner (n = 3/group, one-way analysis of variance). (C) exMt bonded to RAW264.7 cells under transmission electron microscopy (scale bars: 2 μm). (D) Macrophages internalized exMt (n = 3/group, paired t test), as determined by the presence of mouse mitochondrial DNA in mouse exMt-treated human macrophage that were trypsinized to remove surface-bound exMt