ALTERATIONS IN PEROXISOMAL-MITOCHONDRIAL INTERPLAY IN SKELETAL MUSCLE ACCELERATES MUSCLE DYSFUNCTION

Whole-body energy expenditure, as well as glucose and lipid metabolism, are regulated by skeletal muscles, which account for 40-50% of human body mass. Peroxisomes are dynamic organelles that play a crucial role in lipid metabolism and clearance of reactive oxygen species, however their role in muscles remains poorly understood.

To clarify this issue, we generated a muscle-specific transgenic mouse line with peroxisome import deficiency resulting from deletion of peroxisomal biogenesis factor 5 (Pex5). Pex5 inhibition disrupted the tethering between peroxisomes and mitochondria, impaired lipid metabolism and reduced muscle force and exercise performance. Moreover, mitochondrial content and function were also altered, accelerating age-related structural defects, neuromuscular junction degeneration, and muscle atrophy. Altogether, our findings show the importance of preserving peroxisomal function and their contact sites with mitochondria to maintain muscle health during aging.