Mammalian mitohormesis: from mitochondrial stressors to organismal benefits

A variety of stressors, including environmental insults, pathological conditions, and transition states, constantly challenge cells that, in turn, activate adaptive responses to maintain homeostasis. Mitochondria have pivotal roles in orchestrating these responses that influence not only cellular energy production but also broader physiological processes. Mitochondria contribute to stress adaptation through mechanisms including induction of the mitochondrial unfolded protein response (UPR^mt) and the integrated stress response (ISR). These responses are essential for managing mitochondrial proteostasis and restoring cellular function, with each being tailored to specific stressors and cellular milieus. While excessive stress can lead to maladaptive responses, mitohormesis refers to the beneficial effects of low-level mitochondrial stress. Initially studied in invertebrates and cell cultures, recent research has expanded to mammalian models of mitohormesis. In this literature review, we describe the current landscape of mammalian mitohormesis research and identify mechanistic patterns that result in local, systemic, or interorgan mitohormesis. These investigations reveal the potential for targeting mitohormesis for therapeutic benefit and can transform the treatment of diseases commonly associated with mitochondrial stress in humans.