摘要：SummaryMitochondrial function relies on multiple quality control mechanisms, including the release of mitochondrial vesicles. To investigate the ultrastructure and prevalence of mitochondrial membranous protrusions (and, by extension, vesicles) in neurons, we surveyed mitochondria in rat and planarian brains using transmission electron microscopy (EM). We observed that mitochondrial protrusions mostly extend from the outer membrane. Leveraging available 3D EM datasets of the brain, we further analyzed mitochondrial protrusions in neurons of mouse andDrosophilabrains, identifying high-resolution spatial views of these protrusions. To assess whether the abundance of mitochondrial protrusions and mitochondria-derived vesicles respond to cellular stress, we examined neurons expressing fluorescently tagged mitochondrial markers using confocal microscopy with Airyscan and found increased numbers of mitochondrial protrusions and vesicles with mild stress. Future studies using improved spatial resolution with added temporal information may further define the functional implications of mitochondrial protrusions and vesicles in neurons.Graphical AbstractDisplay OmittedHighlights•2D and 3D EM visualizes mitochondrial protrusions in the brain•Rodent,Drosophila, and planarian neurons display similar ultrastructure of protrusions•Light microscopy of mitochondrial markers shows mitochondrial protrusions and vesicles•Neurons under mild stress produce more mitochondrial protrusions and vesiclesOptical Imaging; Neuroscience; Cell Biology; Structural Biology
