Exercise-induced mitochondrial p53 repairs mtDNA mutations in mutator mice.

Area of Science:

• Mitochondrial biology
• Aging research
• Exercise physiology

Background:

• Mitochondrial DNA (mtDNA) mutations and telomere dysfunction are linked to aging.
• Exercise is epidemiologically associated with increased longevity and reduced chronic disease risk.
• The molecular mechanisms behind exercise's benefits are not fully understood.

Purpose of the Study:

• To investigate the molecular mechanisms underlying exercise's beneficial effects on aging.
• To identify novel pathways involved in mitochondrial DNA repair.
• To explore the role of p53 in exercise-mediated mitochondrial maintenance.

Main Methods:

• Utilized transgenic mouse models with proofreading-deficient mitochondrial polymerase gamma (POLG1).
• Examined the effects of endurance exercise on mtDNA mutation burden and multisystem pathology.
• Investigated the role of the tumor suppressor protein p53 in mitochondria during exercise.

Main Results:

• Endurance exercise reduced mtDNA mutation burden and improved lifespan in mutator mice.
• Discovered a POLG1-independent mtDNA repair pathway activated by exercise.
• Demonstrated that p53 translocates to mitochondria, facilitating mtDNA repair and biogenesis.
• Exercise failed to confer benefits in mice lacking muscle-specific p53, highlighting p53's crucial role.

Conclusions:

• Established a new role for p53 in exercise-mediated maintenance of the mtDNA genome.
• Identified mitochondrially targeted p53 as a potential therapeutic strategy for mitochondrial diseases.