mots-c

Demonstrated synergistic interaction between MOTS-c and exercise intervention in C2C12 myotubes and mice. C2C12 cells exposed to AMPK inhibitor (Compound C) showed decreased PGC-1α and MOTS-c expression, confirming AMPK-dependent mechanism. Combined MOTS-c treatment with exercise training enhanced PGC-1α expression beyond either intervention alone, improved mitochondrial biogenesis, attenuated insulin resistance more effectively, and enhanced glucose metabolism. Molecular mechanism: AMPK induces MOTS-c expression through PGC-1α, creating positive feedback loop. Results support MOTS-c as exercise-mimetic agent working synergistically with actual exercise to amplify metabolic benefits including improved insulin sensitivity and glucose homeostasis.

Landmark study demonstrating MOTS-c as exercise-induced peptide improving physical performance across all ages. Mouse studies: systemic treatment enhanced treadmill running ~2-fold in young (2mo.), middle-aged (12mo.), and old (22mo.) mice; old mice doubled running capacity and outran untreated middle-aged cohorts. Late-life treatment (starting 23.5 mo., 3x/week) improved healthspan with enhanced grip strength, stride length, walking distance, reduced blood glucose. Human exercise study: skeletal muscle MOTS-c increased 11.9-fold post-exercise (remained elevated 4h), circulating levels increased 1.6-fold during exercise. Mechanisms: regulates nuclear genes (metabolism, proteostasis), skeletal muscle metabolism (glucose, amino acids), myoblast stress adaptation via HSF1 activation.

First demonstration that mitochondrial genome-encoded factor actively regulates nuclear gene expression. Spatial/temporal analysis shows MOTS-c translocates from mitochondria to nucleus within 0.5-3 hours following glucose restriction, serum deprivation, or oxidative stress (tBHP). Nuclear translocation requires AMPK activation (blocked by Compound C or siRNA against AMPKα). RNA-seq revealed MOTS-c regulates broad range of genes including bona fide NRF2-target genes with antioxidant response elements (ARE). Immunoprecipitation confirmed MOTS-c interaction with stress-responsive transcription factors NFE2L2/NRF2, ATF1/ATF7, JUND. Wild-type but not nuclear-null mutants significantly improved cellular survival under metabolic stress. Establishes integrated bi-genomic cross-communication mechanism.

Original discovery study identifying MOTS-c as 16-amino-acid peptide encoded in mitochondrial 12S rRNA. Primary target organ: skeletal muscle. Mechanism: inhibits folate cycle and de novo purine biosynthesis, increases AICAR levels (5-fold in stable cells), activates AMPK pathway (phosphorylation of Thr172), downstream effects on ACC/CPT-1 for fatty acid oxidation. Mouse studies: prevented age-dependent insulin resistance in old mice, prevented high-fat-diet-induced insulin resistance and obesity, reduced weight gain through increased energy expenditure, decreased liver fat accumulation. Increased NAD+ levels, partially involves SIRT1. Coordinates cellular glucose, mitochondrial, and fatty acid metabolism.

Unbiased metabolomics analysis in diet-induced obese (DIO) mice identified three key metabolic pathways reduced by MOTS-c treatment: sphingolipid metabolism (ceramides, deoxysphingolipids—established T2DM risk predictors), monoacylglycerol metabolism (regulates lipoprotein lipase activity via ANGPTL3/4/8 modulation), and dicarboxylate metabolism (alternative fuel substrates during impaired glucose metabolism). These pathways are upregulated in obesity/T2DM models. MOTS-c improves insulin sensitivity and increases beta-oxidation to prevent fat accumulation through modulating these plasma metabolite pathways. Comparison with other MDPs (humanin, SHLP2) shows MOTS-c uniquely modulates monoacylglycerol and dicarboxylate pathways while sharing common effects on sphingolipids and glutathione. Provides mechanistic understanding of weight/fatty liver reduction.