Urolithin A rewires inter-organellar communication via calcium signaling to promote mitophagy and longevity

Mitochondrial dysfunction and mitophagy deregulation are hallmark features of aging and age-related pathologies. Urolithin A (UA), a potent mitophagy inducer, is known to confer neuroprotection, maintain muscle integrity, and extend healthspan and lifespan across diverse species. Nonetheless, the molecular mechanisms underlying UA-mediated mitophagy remain largely unknown. Here, we demonstrate that UA treatment modulates cytosolic calcium levels, which are essential for initiating robust mitophagy in both neurons and muscles. Transcriptomic and proteomic analyses reveal that UA facilitates the reorganization of inter-organellar communication between endoplasmic reticulum (ER), lysosomes and mitochondria; processes that are highly dependent on calcium signaling. Our findings suggest that UA induces calcium release from the ER and enhances lysosomal activity, while downstream uptake of released calcium from mitochondria, ultimately leads to mitochondrial fission and the successful execution of mitophagy. Consistently, calcium chelation abolishes UA-induced mitophagy, leading to impaired muscle function and diminishes lifespan extension, underscoring the critical role of calcium dynamics. We further found that UA-induced calcium elevation triggers mitochondrial biogenesis through the activation of UNC-43/CaMKII and SKN-1/Nrf2; these pathways are also critical for healthspan and lifespan extension. In human cells, UA supplementation not only induces mitophagy but also enhances mitochondrial metabolism and prevents stress-induced senescence in a calcium-dependent manner. Ultimately, our findings uncover the mechanistic insights of UA-mediated geroprotection and underscore the central role of calcium dynamics in orchestrating the crosstalk and functional wiring of different cellular compartments, thereby sustaining energy homeostasis and overall organismal physiology. Overall design: Four age-synchronized populations of wild type (N2) C. elegans, treated with 50µM of Urolithin A from the L4 stage until day 4 of adulthood, were harvested independently and each was processed as an individual sample. Four additional populations were harvested in the absence of Urolithin A and were used as control samples. Total RNA was extrected from each sample and used for library preparation and RNAseq analysis to obtain gene expression profiles of Urolithin A-treated vs control animals.