Beyond Bioenergetics: Emerging Roles of Mitochondrial Fatty Acid Oxidation in Stress Response and Aging

Mitochondrial fatty acid oxidation (FAO) has long been recognized as a central pathway for energy production, providing acetyl-CoA, NADH, and FADH₂ to sustain cellular growth and survival. However, recent advances have revealed that FAO exerts far broader roles beyond bioenergetics. FAO contributes to redox balance by generating NADPH for antioxidant defense, regulates protein acetylation through acetyl-CoA availability, and modulates stress signaling pathways to support cellular adaptation under nutrient or genotoxic stress. These emerging insights establish FAO as a metabolic hub that integrates energy homeostasis with redox regulation, epigenetic modification, and stress responses. Dysregulation of FAO has been increasingly implicated in aging and diverse pathologies, including cellular senescence, obesity, cancer and fibrosis. In this review, we highlight recent findings and provide an updated perspective on the expanding roles of mitochondrial FAO in stress responses and aging, with particular emphasis on its potential as a therapeutic target in age-associated diseases.