PPARgamma coactivator-1 (PGC-1) α; ;and β serve as master transcriptional regulators of muscle mitochondrial functional capacity and are capable of enhancing muscle endurance when overexpressed in mice. We sought to determine whether muscle-specific transgenic overexpression of PGC-1β affects the detraining response following endurance training. First, we established and validated a mouse exercise training/detraining protocol. Secondly, we found that overexpression of PGC-1β in skeletal muscle of sedentary mice fully recapitulated the training response using multiple physiological and gene expression endpoints. Lastly, overexpression of PGC-1β during the detraining period resulted in a partial prevention of the detraining response. Specifically, an increase in ΔVO2max was maintained in trained mice with muscle overexpression of PGC-1β 6 weeks after cessation of training. However, other detraining responses, including changes in running performance and in situ 1/2 relaxation time (a measure of contractility) were not affected by overexpression of PGC-1β. We conclude that while activation of muscle PGC-1β is sufficient to drive the complete endurance phenotype in sedentary mice, it only partially prevents the detraining response following exercise training suggesting that the process of endurance detraining involves mechanisms beyond the reversal of muscle autonomous mechanisms involved in endurance fitness. In addition, the protocol described here should be useful for assessing early-stage proof-of-concept interventions in pre-clinical models of muscle disuse atrophy.
- Skeletal muscle
- Endurance exercise
- Muscle detraining
- Copyright © 2017, American Journal of Physiology-Endocrinology and Metabolism