Distinct and additive effects of calorie restriction and rapamycin in aging skeletal muscle [CR data set]

As global life expectancy continues to climb, maintaining skeletal muscle function is increasingly essential to ensure a good life quality for aging populations. Calorie restriction (CR) is the most potent and reproducible intervention to extend health and lifespan, but is largely unachievable in humans. Therefore, identification of “CR mimetics” has received much attention. Since CR targets nutrient-sensing pathways centering on mTORC1, rapamycin, the allosteric inhibitor of mTORC1, has been proposed as a potential CR mimetic and counteracts age-related muscle loss. Therefore, we tested whether rapamycin acts via similar mechanisms as CR to slow muscle aging. Contrary to our prediction, long-term CR and rapamycin-treated geriatric mice display distinct skeletal muscle gene expression profiles despite both conferring benefits to aging skeletal muscle. Furthermore, CR improved muscle integrity in a mouse with nutrient-insensitive sustained muscle mTORC1 activity and rapamycin provided additive benefits to CR in aging mouse muscles. Therefore, RM and CR exert distinct, compounding effects in aging skeletal muscle, opening the possibility of parallel interventions to counteract muscle aging. Skeletal muscle mRNA profiles of 30 months-old mice subjected to calorie restriction (70% of AIN93M diet with 1.43x(vitamins + minerals)) for 15 months from the age of 15 months were generated by next-generation sequencing.