Document Detail

The effect of training on the expression of mitochondrial biogenesis- and apoptosis-related proteins in skeletal muscle of patients with mtDNA defects.
MedLine Citation:
PMID:  17551003     Owner:  NLM     Status:  MEDLINE    
Mitochondrial myopathy patients (MMPs) have impaired oxidative phosphorylation and exercise intolerance. Endurance training of MMPs improves exercise tolerance, but also increases mutational load. To assess the regulation of mitochondrial content in MMPs, we measured proteins involved in 1) biogenesis, 2) oxidative stress, and 3) apoptosis in MMPs and healthy controls (HCs) both before and after endurance training. Before training, MMPs had a greater mitochondrial content, along with a 1.4-fold (P < 0.05) higher expression of the biogenesis regulator peroxisome proliferator-activated receptor-gamma coactivator-1alpha (PGC-1alpha). The DNA repair enzyme 8-oxoguanine DNA glycolase-1 (OGG-1), the antioxidant manganese superoxide dismutase (MnSOD), and the apoptotic proteins AIF and Bcl-2 were higher in MMPs compared with HCs. Aconitase, an enzyme sensitive to oxidative stress, was 52% lower (P < 0.05) in MMPs when calculated based on an estimate of mitochondrial volume and oxidative stress-induced protein modifications tended to be higher in MMPs compared with HCs. Endurance training (ET) induced increases in mitochondrial content in both HC subjects and MMPs, but there was no effect of training on the regulatory proteins Tfam or PGC-1alpha. In MMPs, training induced a selective reduction of OGG-1, an increase in MnSOD, and a reduction in aconitase activity. Thus, before training, MMPs exhibited an adaptive response of nuclear proteins indicative of a compensatory increase in mitochondrial content. Following training, several parallel adaptations occurred in MMPs and HCs, which may contribute to previously observed functional improvements of exercise in MMPs. However, our results indicate that muscle from MMPs may be exposed to greater levels of oxidative stress during the course of training. Further investigation is required to evaluate the long-term benefits of endurance training as a therapeutic intervention for mitochondrial myopathy patients.
Peter J Adhihetty; Tanja Taivassalo; Ronald G Haller; Donald R Walkinshaw; David A Hood
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't     Date:  2007-06-05
Journal Detail:
Title:  American journal of physiology. Endocrinology and metabolism     Volume:  293     ISSN:  0193-1849     ISO Abbreviation:  Am. J. Physiol. Endocrinol. Metab.     Publication Date:  2007 Sep 
Date Detail:
Created Date:  2007-09-03     Completed Date:  2007-10-24     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  100901226     Medline TA:  Am J Physiol Endocrinol Metab     Country:  United States    
Other Details:
Languages:  eng     Pagination:  E672-80     Citation Subset:  IM    
School of Kinesiology and Health Science, York University, Toronto, Ontario, Canada M3J 1P3.
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MeSH Terms
Apoproteins / metabolism*
Cell Differentiation
DNA, Mitochondrial / genetics*
Genetic Predisposition to Disease / genetics
Mitochondrial Diseases / genetics*,  metabolism*,  pathology
Mitochondrial Proteins / metabolism*
Muscle, Skeletal / physiopathology*
Reg. No./Substance:
0/Apoproteins; 0/DNA, Mitochondrial; 0/Mitochondrial Proteins

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