Title

Modulation of autophagy signaling with resistance exercise and protein ingestion following short-term energy deficit

Date of this Version

2015

Document Type

Journal Article

Grant Number

ARC Linkage Project grant # LP100100010

Publication Details

Citation only

Smiles, W. J., Areta, J. L., Coffey, V. G., Phillips, S. M., Moore, D. R., Stellingwerff, T., Burke, L. M., Hawley, J. A., & Camera, D. M. (2015). Modulation of autophagy signaling with resistance exercise and protein ingestionfollowing short-term energy deficit. American Journal of Physiology - Regulatory, Integrative and Comparative Physiology, 309(5), R603-R612.

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2015 HERDC submission

Copyright © 2015 the American Physiological Society

ISSN

0363-6119

Abstract

Autophagy contributes to remodeling of skeletal muscle and is sensitive to contractile activity and prevailing energy availability. We investigated changes in targeted genes and proteins with roles in autophagy following 5 days of energy balance (EB), energy deficit (ED), and resistance exercise (REX) after ED. Muscle biopsies from 15 subjects (8 males, 7 females) were taken at rest following 5 days of EB [45 kcal·kg fat free mass (FFM)−1·day−1] and 5 days of ED (30 kcal·kg FFM−1·day−1). After ED, subjects completed a bout of REX and consumed either placebo (PLA) or 30 g whey protein (PRO) immediately postexercise. Muscle biopsies were obtained at 1 and 4 h into recovery in each trial. Resting protein levels of autophagy-related gene protein 5 (Atg5) decreased after ED compared with EB (∼23%, P < 0.001) and remained below EB from 1 to 4 h postexercise in PLA (∼17%) and at 1 h in PRO (∼18%, P < 0.05). In addition, conjugated Atg5 (cAtg12) decreased below EB in PLA at 4 h (∼20, P < 0.05); however, its values were increased above this time point in PRO at 4 h alongside increases in FOXO1 above EB (∼22–26%, P < 0.05). Notably, these changes were subsequent to increases in unc-51-like kinase 1Ser757 phosphorylation (∼60%) 1 h postexercise in PRO. No significant changes in gene expression of selected autophagy markers were found, but EGR-1 increased above ED and EB in PLA (∼417–864%) and PRO (∼1,417–2,731%) trials 1 h postexercise (P < 0.001). Postexercise protein availability, compared with placebo, can selectively promote autophagic responses to REX in ED.

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This document has been peer reviewed.