Oleic acid up-regulates myosin heavy chain (MyHC) 1 expression and increases mitochondrial mass and maximum respiration in C2C12 myoblasts

摘要

Skeletal muscle is divided into type 1 and type 2 fibers. Type 1 fibers are rich in mitochondria, have high oxidative metabolism, and are resistant to fatigue. Muscle-specific overexpression of peroxisome proliferator-activated receptor (PPAR)delta drastically increases the number of type 1 fibers. We focused on oleic acid, an omega-9 monounsaturated fatty acid, as a factor that activates PPAR delta. In this study, we examined the effects of oleic acid on the muscle fiber type of C2C12 myotubes and its relationship with PPAR delta. Our results showed that oleic acid treatment increased the levels of myosin heavy chain (MyHC)1, a known type 1 fiber marker, as well as mitochondrial mass and maximum respiration in C2C12 cells. To confirm the relationship between PPAR delta activation and oleic acid-induced MyHC1 increase, we examined the effects of oleic acid in PPAR delta knockdown C2C12 myoblasts. We found that oleic acid supplementation increased the mRNA expression of MyHC1 in PPAR delta-knockdown C2C12 cells. Our data suggest that oleic acid increases type 1 fiber levels in C2C12 myotubes in a PPAR delta-independent manner. (C) 2020 The Author(s). Published by Elsevier Inc.