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Ageing has no effect on the regulation of the ubiquitin proteasome-related genes and proteins following resistance exercise
Stefanetti, Renae J. Zacharewicz, Evelyn Della Gatta, Paul A. Garnham, Andrew Russell, Aaron P. Lamon, Séverine
Stefanetti, Renae J.
Zacharewicz, Evelyn
Della Gatta, Paul A.
Garnham, Andrew
Russell, Aaron P.
Lamon, Séverine
Abstract
Skeletal muscle atrophy is a critical component of the ageing process. Age-related muscle wasting is due to disrupted muscle protein turnover, a process mediated in part by the ubiquitin proteasome pathway ( UPP ). Additionally, older subjects have been observed to have an attenuated anabolic response, at both the molecular and physiological levels, following a single-bout of resistance exercise ( RE ). We investigated the expression levels of the UPP-related genes and proteins involved in muscle protein degradation in 10 older ( 60–75 years ) vs. 10 younger ( 18–30 years ) healthy male subjects at basal as well as 2 h after a single-bout of RE. MURF1, atrogin-1 and FBXO40, their substrate targets PKM2, myogenin, MYOD, MHC and EIF3F as well as MURF1 and atrogin-1 transcriptional regulators FOXO1 and FOXO3 gene and/or protein expression levels were measured via real time PCR and western blotting, respectively. At basal, no age-related difference was observed in the gene/protein levels of atrogin-1, MURF1, myogenin, MYOD and FOXO1/3. However, a decrease in FBXO40 mRNA and protein levels was observed in older subjects, while PKM2 protein was increased. In response to RE, MURF1, atrogin-1 and FBXO40 mRNA were upregulated in both the younger and older subjects, with changes observed in protein levels. In conclusion, UPP-related gene/protein expression is comparably regulated in healthy young and old male subjects at basal and following RE. These findings suggest that UPP signaling plays a limited role in the process of age-related muscle wasting. Future studies are required to investigate additional proteolytic mechanisms in conjunction with skeletal muscle protein breakdown ( MPB ) measurements following RE in older vs. younger subjects.
Keywords
skeletal muscle, resistance exercise, muscle protein breakdown, ubiquitin-proteasome, atrogene signaling
Date
2014
Type
Journal article
Journal
Frontiers in Physiology
Book
Volume
5
Issue
Page Range
1-10
Article Number
ACU Department
Centre for Exercise and Nutrition
Faculty of Health Sciences
Faculty of Health Sciences
Collections
Relation URI
Source URL
Event URL
Open Access Status
Open access
License
File Access
Open
Notes
© 2014 Stefanetti, Zacharewicz, Della Gatta, Garnham, Russell and Lamon. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.