Caloric Restriction Normalizes Obesity-Induced Alterations on Regulators of Skeletal Muscle Growth Signaling.

The objective of this study was to establish the impact of caloric restriction on high fat diet-induced alterations on regulators of skeletal muscle growth. We hypothesized that caloric restriction would reverse the negative effects of high fat diet-induced obesity on REDD1 and mTOR-related signaling. Following an initial 8 week period of HF diet-induced obesity, caloric restriction (CR ~30 %) was employed while mice continued to consume either a low (LF) or high fat (HF) diet for 8 weeks. Western analysis of skeletal muscle showed that CR reduced (p < 0.05) the obesity-related effects on the lipogenic protein, SREBP1. Likewise, CR reduced (p < 0.05) the obesity-related effects on the hyperactivation of mTORC1 and ERK1/2 signaling to levels comparable to the LF mice. CR also reduced (p < 0.05) obesity-induced expression of negative regulators of growth, REDD1 and cleaved caspase 3. These findings have implications for on the reversibility of dysregulated growth signaling in obese skeletal muscle, using short-term caloric restriction.