Rab7 activation ameliorates impaired lysosome dynamics and mitophagic flux during chronic iron overload

Iron homeostasis is essential for cellular function, yet iron overload is linked to pathologies including cardiovascular disease and metabolic syndrome. Although excess iron has been associated with impaired autophagy and mitochondrial dysfunction, the effects of iron overload on lysosomal dynamics and mitophagy remain poorly defined. In this study, we demonstrate that iron overload disrupts mitochondrial morphology and lysosomal homeostasis, accompanied by iron accumulation in both organelles. While mitophagy is triggered upon iron overload, mitophagic flux is impaired, suggesting a defect in mitophagosome maturation and incomplete clearance. Notably, lysosomes in iron loaded cells were hyper-acidic and degradative, but became enlarged, perinuclear, and less motile, suggesting that altered lysosomal dynamics may contribute to defective mitophagic clearance. Interestingly, pharmacological activation of Rab7 restores lysosomal motility and mitophagic flux under iron overload conditions. It also improves mitochondrial function and cell viability. Together, these findings indicate that iron overload disrupts organelle homeostasis by impairing lysosomal and mitochondrial dynamics, ultimately arresting mitophagic flux due to altered lysosome dynamics and promoting cell death. Targeted activation of Rab7 mitigates these iron-induced effects, providing a potential therapeutic target for iron overload-induced cell death and tissue damage.