Cross comparison of imaging strategies of mitochondria in C. elegans during aging

Mitochondria are double membrane-bound organelles with pleiotropic roles in the cell, including energy production through aerobic respiration, calcium signaling, metabolism, proliferation, immune signaling, and apoptosis. Dysfunction of mitochondria is associated with numerous physiological consequences and drives various diseases, and is one of twelve biological hallmarks of aging, linked to aging pathology. There are many distinct changes that occur to the mitochondria during aging including changes in mitochondrial morphology, which can be used as a robust and simple readout of mitochondrial quality and function. Although mitochondrial morphology alone cannot be used to conclude the quality of mitochondria, it is highly correlated with mitochondrial function whereby mitochondria exhibit increased fragmentation with age in multiple cell types of the nematode C. elegans. Thus, C. elegans serve as a robust model for rapidly measuring mitochondrial morphology changes during aging. To standardize imaging methods for mitochondrial morphology in C. elegans, we provide a detailed comparative characterization of several transgenic constructs, highlighting benefits and caveats for aging biology studies.