Regulation of FAT/CD36 expression in human skeletal muscle

FAT/CD36 is an integral membrane protein and plays an important role in transporting long chain fatty acids into skeletal muscle cells. The aim of this study was to gain insight into what regulates FAT/CD36 expression in human skeletal muscle. We examined the role of FAT/CD36 in primary human skeletal muscle cells by measuring the expression of mRNA for FAT/CD36 via RT‐PCR (CD36/18s). During cellular differentiation from myoblasts to myotubes, mRNA expression of FAT/CD36 is significantly increased by 83%. Treatment with fatty acids (500uM 1:1 oleate:palmitate) for 24h significantly increased FAT/CD36 expression 5‐fold (P<0.05), whereas treatment (24h) with a PPAR delta agonist increased FAT/CD36 expression 1.5‐fold compared to controls. FAT/CD36 expression significantly increased in a dose‐dependent manner following treatment (24h) with 10nM (5‐fold), 100nM (30‐fold), and 1,000nM (70‐fold) insulin compared to control (0nM insulin) (P<0.05). Our preliminary findings also show that FAT/CD36 mRNA expression is significantly elevated 4.5‐fold in obese compared to lean muscle cells (P<0.05). We conclude that FAT/CD36 expression is upregulated in obese skeletal muscle and following treatment with either fatty acids or insulin.