MOTS-C

Most peptides come from the nuclear genome; MOTS-C does not. It is encoded by mitochondrial DNA, specifically an open reading frame (ORF) inside the 12S rRNA gene, hence the abbreviation. With 16 amino acids it belongs to a small group of mitochondrially encoded peptides.

Where the research comes from:

• First described in 2015 by Lee et al. at USC, in Pinchas Cohen's group.
• Since then one of the most studied molecules in mitochondrial research and one of the first well-characterized mitokines.

How it acts in research models:

• The target is the AMPK axis, reached through the folate-methionine one-carbon pathway.
• AMPK is the cell's energy sensor; once activated it steers glucose uptake, fatty acid oxidation and the formation of new mitochondria.
• Under metabolic stress, MOTS-C moves into the nucleus in an AMPK-dependent way and regulates stress-response genes there, partly together with the transcription factor NRF2.

The working hypothesis: MOTS-C is an endocrine signal between mitochondrion and nucleus that reports the cell's energy state. Its levels in several tissues track age, physical activity and metabolic status; in humans, endogenous expression in skeletal muscle and blood rises after exercise, and in mice of every age physical performance improved under MOTS-C. Typical studies run for weeks in cell culture or animal models and ask about insulin sensitivity, metabolic flexibility and age-related change. Below: the original paper, the nucleus study, the exercise study and a review on diabetes and aging.

The available preclinical work describes no pronounced toxicity profile for MOTS-C, in keeping with an endogenous peptide; according to the studies it counts as well tolerated.

• Injection site: slight redness, a feeling of pressure or passing irritation is the most common observation with subcutaneous dosing.
• Circulation: isolated mentions of warmth, slight dizziness or fatigue shortly after administration.
• Blood sugar: because MOTS-C reaches into glucose uptake and energy metabolism via AMPK, possible effects on blood glucose are discussed in the literature.
• Evidence: human studies barely exist, nearly everything comes from cell culture and animal models.

This summary is no substitute for medical advice.

• The mitochondrial-derived peptide MOTS-c promotes metabolic homeostasis - the first description from 2015.
• MOTS-c translocates to the nucleus to regulate nuclear gene expression under metabolic stress - shows the AMPK-dependent move into the nucleus and the interplay with NRF2.
• MOTS-c is an exercise-induced regulator of physical decline and muscle homeostasis - performance data from mice of three age groups and expression data from human muscle after exercise.
• Mitochondrial-Encoded Peptide MOTS-c, Diabetes, and Aging-Related Diseases - a 2023 review focused on both types of diabetes and on age-associated diseases.