Mitochondria-derived vesicles in neurodegeneration

Mitophagy is a well-characterized and redundant recycling system for damaged mitochondria and a marker of organelle quality (Picca et al., 2023). Yet, the assessment of mitophagy in vivo remains a challenge. The characterization of the endosomal-lysosomal pathways supporting the endocytic trafficking has provided invaluable information also into mitophagy signaling. The endocytic pathway has been implicated in preserving mitochondrial quality via generation of mitochondria-derived vesicles (MDVs) and, as such, has been related to mitophagy tasks (Ferrucci et al., 2024). Altered mitophagy and MDV signaling accompany brain aging and neurodegenerative conditions (Ferrucci et al., 2024). However, how MDVs can be best characterized to be exploited as hallmarks of health and disease is debated. MDVs may be a trait d’union between dysfunctional mitophagy and decline of cell homeostasis through shuttling and/or being themselves mitochondria-derived damage-associated molecular patterns. These latter by instigating chronic low-grade inflammation may support neuroinflammation and neurodegeneration (Ferrucci et al., 2024). Alternatively, MDVs may rescue mitochondrial bioenergetics of neighbouring cells and favour neuronal health by transferring functional organelles. However, what defines one or the other role of MDVs and whether the outcome is mediated by vesicle subpopulations released under different metabolic triggers remain to be defined. Herein, we discuss MDVs as surrogate and more accessible measures of mitophagy. We also highlight the importance of addressing challenges in MDVs isolation and characterization to appreciate their signaling roles in neurodegeneration.