MOTS-c

MOTS-c, short for mitochondrial open reading frame of the 12S rRNA-c, is a 16-amino-acid peptide encoded by mitochondrial DNA. It is studied as part of communication between mitochondria and the cell nucleus in response to metabolic stress and physical exercise. Naturally produced MOTS-c must be distinguished from experimental administration of a synthetic peptide.

Research suggests that MOTS-c acts as a signalling molecule between mitochondria and the nucleus. During energy shortage, intense exercise or other metabolic stress, the peptide may move into the nucleus and influence genes involved in energy production, antioxidant defence and cellular adaptation. Through these pathways, it may contribute to metabolic balance and efficient energy use.

One of the most studied proposed mechanisms involves AMPK, a central cellular energy sensor. Activation of AMPK promotes glucose utilisation, increases fatty-acid oxidation and shifts cells towards more energy-efficient metabolism. Animal studies have reported improved insulin sensitivity and reduced metabolic disturbances caused by high-fat diets, as well as less development of obesity in some models. These findings have made MOTS-c an important subject in metabolic-disease research.

MOTS-c has also attracted attention in exercise physiology. Human studies have found that strenuous exercise can substantially change the body’s natural MOTS-c concentration. In one study, skeletal-muscle MOTS-c increased approximately 11.9-fold after exercise, while plasma levels rose about 1.6-fold during exercise and remained elevated for a period afterwards. These findings suggest that endogenous MOTS-c participates in the body’s adaptation to physical activity and may be one signal involved in training-related metabolic adaptation.

Preclinical mouse studies have reported improved physical performance in animals of different ages after experimental MOTS-c administration. Effects were observed in young, middle-aged and old mice. Treatment begun at a very advanced age was also associated with greater overall activity and improved healthspan, although this did not necessarily mean a significant extension of maximum lifespan. These results have encouraged further research into whether any comparable effects could occur in humans.

The relationship between MOTS-c and ageing is another research focus. Natural levels of the peptide appear to decline with age. Researchers have proposed that lower MOTS-c may be associated with impaired mitochondrial function, increased insulin resistance and reduced physical capacity. This has prompted investigation into whether understanding its mechanisms could inform future approaches to healthy-ageing biology and age-related metabolic change. These questions remain experimental.

Possible effects on inflammation and oxidative stress are also being studied. Laboratory and animal research suggests that MOTS-c may reduce inflammatory signalling, support antioxidant systems and protect mitochondria during metabolic stress. These observations have led to research in cardiovascular, neurodegenerative and other chronic-disease models in which mitochondrial dysfunction is important. Most evidence in these areas still comes from cells and animals.

Most data on the effects of synthetic MOTS-c come from cell and animal models. Human research has mainly shown that exercise alters endogenous MOTS-c in muscle or blood. This does not demonstrate that synthetic MOTS-c treats disease or safely improves physical performance in humans.

MOTS-c is an important subject in mitochondrial-signalling research, particularly in relation to AMPK, glucose metabolism and adaptation to exercise. Potential medical applications remain experimental. Controlled human studies would need to evaluate the effectiveness, pharmacokinetics and safety of synthetic MOTS-c separately from observations of the naturally occurring peptide.