title: Modulation of autophagy signaling with resistance exercise and protein ingestion following short-term energy deficit.
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 1(Ser757) 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.
authors.affiliation: Mary MacKillop Institute for Health Research, Centre for Exercise and Nutrition, Australian Catholic University, Melbourne, Victoria, Australia;
authors.forename: William J
authors.initials: WJ
authors.lastname: Smiles
authors.affiliation: Mary MacKillop Institute for Health Research, Centre for Exercise and Nutrition, Australian Catholic University, Melbourne, Victoria, Australia;
authors.forename: José L
authors.initials: JL
authors.lastname: Areta
authors.affiliation: Bond Institute of Health and Sport and Faculty of Health Sciences and Medicine, Bond University, Queensland, Australia;
authors.forename: Vernon G
authors.initials: VG
authors.lastname: Coffey
authors.affiliation: Exercise Metabolism Research Group, Department of Kinesiology, McMaster University, Hamilton, Ontario, Canada;
authors.forename: Stuart M
authors.initials: SM
authors.lastname: Phillips
authors.affiliation: Faculty of Kinesiology and Physical Education, University of Toronto, Toronto, Ontario, Canada;
authors.forename: Daniel R
authors.initials: DR
authors.lastname: Moore
authors.affiliation: Canadian Sport Institute-Pacific, Victoria, Canada; and.
authors.forename: Trent
authors.initials: T
authors.lastname: Stellingwerff
authors.affiliation: Department of Sports Nutrition, Australian Institute of Sport, Canberra, Australia.
authors.forename: Louise M
authors.initials: LM
authors.lastname: Burke
authors.affiliation: Mary MacKillop Institute for Health Research, Centre for Exercise and Nutrition, Australian Catholic University, Melbourne, Victoria, Australia; Research Institute for Sport and Exercise Sciences, Liverpool John Moores University, Liverpool, United Kingdom;
authors.forename: John A
authors.initials: JA
authors.lastname: Hawley
authors.affiliation: Mary MacKillop Institute for Health Research, Centre for Exercise and Nutrition, Australian Catholic University, Melbourne, Victoria, Australia; donny.camera@acu.edu.au.
authors.forename: Donny M
authors.initials: DM
authors.lastname: Camera
mesh_terms: D000328:Adult; D001343:Autophagy / Q000235:genetics; D001706:Biopsy; D002149:Energy Intake; D004734:Energy Metabolism; D005260:Female; D005786:Gene Expression Regulation; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins / Q000235:genetics / Q000378:metabolism; D008297:Male; D009124:Muscle Proteins / Q000235:genetics / Q000378:metabolism; D018482:Muscle, Skeletal / Q000378:metabolism* / Q000473:pathology; D012333:RNA, Messenger / Q000378:metabolism; D055070:Resistance Training; D015398:Signal Transduction / Q000235:genetics; D013312:Stress, Physiological; D013997:Time Factors; D014739:Victoria; D000067816:Whey Proteins / Q000008:administration & dosage* / Q000378:metabolism; D055815:Young Adult
chemical_list: D047908:Intracellular Signaling Peptides and Proteins; D009124:Muscle Proteins; D012333:RNA, Messenger; D000067816:Whey Proteins
keywords: autophagy; muscle protein breakdown; resistance exercise; skeletal muscle