Quantify nanoscopic alterations associated with mitochondrial dysfunctions using three-dimensional single-molecule localization microscopy

ABSTRACT The morphology of mitochondria provides insights into their functions. Three-dimensional (3D) single-molecule localization microscopy (SMLM) uniquely enables the analysis of mitochondrial morphological features individually, thanks to its high resolution. However, nearly all reported studies of mitochondrial morphology have been qualitative and without statistical analysis. We report a quantitative method to extract mitochondrial morphological metrics, including volume, aspect ratio, and local protein density, from 3D SMLM images, with single-mitochondrion sensitivity. We validated our approach using simulated ground-truth SMLM images of mitochondria. We further tested our morphological analysis on mitochondria that have been altered functionally and morphologically in controlled manners. This work sets the stage to analyze mitochondrial morphological alterations associated with disease progression quantitatively.