Reduced removal of damaged cell parts may cause cigarette smoke to trigger cell aging linked to chronic lung disease

Cigarette smoke exposure at concentrations of 0.2-0.75% impairs mitophagy and is associated with cellular senescence in lung cells.

• Impaired mitophagy and accumulation of damaged mitochondria were observed in human lung fibroblasts and small airway epithelial cells exposed to cigarette smoke extract.
• Reduced translocation of Parkin to damaged mitochondria was linked to increased levels of cytoplasmic p53 due to cigarette smoke exposure.
• Similar impaired Parkin translocation and mitophagy were also found in mouse lungs with emphysema after 6 months of cigarette smoke exposure.
• Patients with chronic obstructive pulmonary disease exhibited impaired mitophagy and increased cellular senescence in primary small airway epithelial cells.
• Restoration of mitophagy using a mitochondria-targeted antioxidant reduced mitochondrial mass accumulation and delayed cellular senescence in Parkin-overexpressing cells.

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