| Autor: |
Margolis LM; Military Nutrition Division, U.S. Army Research Institute of Environmental Medicine, Natick, Massachusetts., Carrigan CT; Military Nutrition Division, U.S. Army Research Institute of Environmental Medicine, Natick, Massachusetts., Murphy NE; Military Nutrition Division, U.S. Army Research Institute of Environmental Medicine, Natick, Massachusetts., DiBella MN; Military Nutrition Division, U.S. Army Research Institute of Environmental Medicine, Natick, Massachusetts.; Oak Ridge Institute of Science and Education, Belcamp, Maryland., Wilson MA; Military Nutrition Division, U.S. Army Research Institute of Environmental Medicine, Natick, Massachusetts., Whitney CC; Military Nutrition Division, U.S. Army Research Institute of Environmental Medicine, Natick, Massachusetts., Howard EE; Military Nutrition Division, U.S. Army Research Institute of Environmental Medicine, Natick, Massachusetts., Pasiakos SM; Military Performance Division, U.S. Army Research Institute of Environmental Medicine, Natick, Massachusetts., Rivas DA; Nutrition, Exercise Physiology and Sarcopenia Laboratory, Jean Mayer USDA Human Nutrition Research Center on Aging, Tufts University, Boston, Massachusetts. |
| Abstrakt: |
Posttranscriptional regulation by microRNA (miRNA) facilitates exercise and diet-induced skeletal muscle adaptations. However, the impact of diet on miRNA expression during postexercise recovery remains unclear. The objective of this study was to examine the effects of consuming carbohydrate or a nutrient-free control on skeletal muscle miRNA expression during 3 h of recovery from aerobic exercise. Using a randomized, crossover design, seven men (means ± SD, age: 21 ± 3 yr; body mass: 83 ± 13 kg; V̇o 2peak : 43 ± 2 mL/kg/min) completed two-cycle ergometry glycogen depletion trials followed by 3 h of recovery while consuming either carbohydrate (CHO: 1 g/kg/h) or control (CON: nutrient free). Muscle biopsy samples were obtained under resting fasted conditions at baseline and at the end of the 3-h recovery (REC) period. miRNA expression was determined using unbiased RT-qPCR microarray analysis. Trials were separated by 7 days. Twenty-five miRNAs were different ( P < 0.05) between CHO and CON at REC, with Let7i-5p and miR-195-5p being the most predictive of treatment. In vitro overexpression of Let7i-5p and miR-195-p5 in C2C12 skeletal muscle cells decreased ( P < 0.05) the expression of protein breakdown ( Foxo1 , Trim63 , Casp3 , and Atf4 ) genes, ubiquitylation, and protease enzyme activity compared with control. Energy sensing ( Prkaa1 and Prkab1 ) and glycolysis ( Gsy1 and Gsk3b ) genes were lower ( P < 0.05) with Let7i-5p overexpression compared with miR-195-5p and control. Fat metabolism ( Cpt1a , Scd1 , and Hadha ) genes were lower ( P < 0.05) in miR-195-5p than in control. These data indicate that consuming CHO after aerobic exercise alters miRNA profiles compared with CON, and these differences may govern mechanisms facilitating muscle recovery. NEW & NOTEWORTHY Results provide novel insight into effects of carbohydrate intake on the expression of skeletal muscle microRNA during early recovery from aerobic exercise and reveal that Let7i-5p and miR-195-5p are important regulators of skeletal muscle protein breakdown to aid in facilitating muscle recovery. |
