Endurance Training Boosts Muscle Mitochondria Through MOTS-c Peptide Secretion
Background
Mitochondria are the powerhouses of our cells, and their function is critical for skeletal muscle performance and overall metabolic health. The peptide MOTS-c (mitochondrial open reading frame of 12S rRNA-c) is a fascinating molecule derived directly from mitochondria, known to influence metabolism. However, the precise relationship between MOTS-c, skeletal muscle mitochondrial function, and the adaptations observed with endurance exercise has remained unclear.
Results
The study revealed a strong, positive association between circulating MOTS-c levels and aerobic exercise capacity in both human and mouse models. Specifically, marathon runners demonstrated elevated serum MOTS-c compared to sedentary subjects, correlating with their superior maximal oxygen uptake. In mice, long-term endurance training resulted in a significant increase in both serum MOTS-c and skeletal muscle mitochondrial respiration rates. The most critical finding was that endurance training enhances skeletal muscle mitochondrial respiratory function by promoting MOTS-c secretion and activating the AMPK/PGC-1α signaling pathway, directly linking this peptide to exercise adaptation. This mechanistic insight suggests that MOTS-c acts as a crucial mediator in the beneficial effects of exercise on muscle mitochondria.
Why It Matters
This research provides a novel mechanistic understanding of how endurance training improves skeletal muscle mitochondrial function, highlighting MOTS-c as a key player. The findings suggest that circulating MOTS-c levels could serve as an important biomarker for predicting aerobic exercise capacity, assessing body fat status, monitoring endurance training load, and evaluating overall physical function. This opens avenues for potential therapeutic strategies, where modulating MOTS-c levels could enhance exercise benefits or mitigate age-related decline in mitochondrial function, potentially leading to interventions that mimic the benefits of exercise for individuals unable to train.