Rejuvenating Inter-organellar Communication Via Mitophagy in Ageing and Neurodegeneration.

Abstract

Ageing and neurodegeneration are characterized by the progressive breakdown of organellar communication between mitochondria, the endoplasmic reticulum (ER), and lysosomes. Recent findings underline mitophagy as a central modulator of this interconnected network. Impaired mitophagy induces ER fragmentation, lysosomal dysfunction, imbalanced mitochondrial dynamics, and deregulation of calcium homeostasis, suggesting that mitochondrial turnover is essential for the maintenance of global organellar architecture. Conversely, restoring mitophagy re-establishes structural integrity and functional coordination across subcellular compartments. Notably, Urolithin A (UA) rejuvenates inter-organelle crosstalk through a defined calcium-dependent mechanism. UA promotes ER-derived calcium release via ITR-1/ITPR/InsP3R, EMC-3/EMC3, and TMCO-1/TMCO1, and enhances calcium uptake into mitochondria through MCU-1/MCU. This calcium flux activates DRP-1/DRP1-mediated mitochondrial fission, facilitating mi-tophagy initiation. In parallel, calcium-dependent activation of the UNC-43/CaMKII-SKN-1/Nrf2 axis stimulates mitochondrial biogenesis and metabolic adaptation. Furthermore, UA increases ER-mitochondrial contact sites (MAMs) and restores lysosomal activity, thereby re-establishing functional inter-organellar communication in nematodes and mammalian cells. These findings establish mitophagy as a central node of cellular and tissue homeostasis, acting through the stabilization of the organellar communication network to promote healthspan and lifespan while highlighting the need for future studies to validate these mechanisms across human tissues and disease-relevant cellular contexts.