Effects of Acute Aerobic Exercise on Whole Genome Nucleosome Maps in Skeletal Muscle of Lean vs Overweight/Obese Men

Acute aerobic exercise has been shown to improve skeletal muscle mitochondrial function and completeness of fatty acid ß-oxidation which contribute to improved insulin sensitivity. The effectiveness of acute exercise on improving mitochondrial adaptations, leading to improved insulin sensitivity, in overweight/obese (Ov/Ob) individuals is controversial. This study aimed to determine the effects of acute exercise on epigenetic regulation, specifically nucleosome positioning, of genes involved in skeletal muscle mitochondrial adaptations in lean vs Ov/Ob men. Overall design: 30 men, aged 19-30 years, were recruited and divided into two groups: lean (BMI<25, 18.5- 24.1 kg/m2, n=15) and Ov/Ob (BMI=25, 25.5- 36.9 kg/m2, n=15). Vastus lateralis muscle biopsy samples were collected at rest, following an overnight fast (Pre; n=14 in lean Pre and n=15 in Ov/Ob Pre). Subjects then ingested a standardized high-carbohydrate breakfast (7 kcal/kg; 60% carbohydrate, 25% fat, 15% protein). Four hours later, they performed an acute bout of cycling exercise (50% VO2max, expending ~650 kcal) and vastus lateralis muscle biopsy samples were collected immediately after the exercise bout (Post; n=15 in lean Post and in Ov/Ob Post). Mononucleosomal DNA was extracted from vastus lateralis muscle samples (n=5 per group) and MNase-seq was performed using the Illumina platform and analyzed via HOMER and custom scripts, as previously described (Henagan, TM et al 2015).