MMP-low HSCs contain more fragmented mitochondria. (Ai) Representative 3-dimensional immunofluorescent confocal images of TOM20 (red, TOM20; blue, DAPI; scale bar, 1 μm). (Aii) The total number of mitochondrial fragments per cell. (Aiii-Aiv) The average area and volume per fragment of mitochondria in each cell. (B) Representative 3-dimensional immunofluorescent confocal images (left) of DRP1 (green, DRP1; blue, DAPI; scale bar, 1 μm) and quantification (right) of fluorescence intensity of localized DRP1 foci above threshold. (C) Two-dimensional immunofluorescent confocal images (left; scale bar, 5 μm) of TOM20 (red), DRP1 (green), DAPI (blue), merged (yellow); inset contains magnified images, quantification of colocalization of TOM20 and DRP1 (right). All analyses were performed in MMP-low and MMP-high CD90⁺ PB HSCs. Data are presented as mean ± standard deviation; Student t test: *P < .05, **P < .01, ****P < .0001.