Abstract | CONTEXT: Reduced mitochondrial coupling ( ATP/O2 [P/O]) is associated with sedentariness and insulin resistance. Interpreting the physiological relevance of P/O measured in vitro is challenging. OBJECTIVE: To evaluate muscle mitochondrial function and associated transcriptional profiles in nonobese healthy individuals distinguished by their in vivo P/O. DESIGN: Individuals from an ancillary study of Comprehensive Assessment of Long-term Effects of Reducing Intake of Energy phase 2 were assessed at baseline. SETTING: The study was performed at Pennington Biomedical Research Center. PARTICIPANTS: Forty-seven (18 males, 26-50 y of age) sedentary, healthy nonobese individuals were divided into 2 groups based on their in vivo P/O. INTERVENTION: None. Main Outcome(s): Body composition by dual-energy x-ray absorptiometry, in vivo mitochondrial function (P/O and maximal ATP synthetic capacity) by 31P-magnetic resonance spectroscopy and optical spectroscopy were measured. A muscle biopsy was performed to measure fiber type, transcriptional profiling (microarray), and protein expressions. RESULTS: No differences in body composition, peak aerobic capacity, type I fiber content, or mitochondrial DNA copy number were observed between the 2 groups. Compared with the uncoupled group (lower P/O), the coupled group (higher P/O) had higher rates of maximal ATP synthetic capacity (maximal ATP synthetic capacity, P < .01). Transcriptomics analyses revealed higher expressions of genes involved in mitochondrial remodeling and the oxidative stress response in the coupled group. A trend for higher mitonuclear protein imbalance (P = .06) and an elevated mitochondrial unfolded protein response ( heat shock protein 60 protein; P = .004) were also identified in the coupled group. CONCLUSIONS: Higher muscle mitochondrial coupling is accompanied by an overall elevation in mitochondrial function, a novel transcriptional signature of oxidative stress and mitochondrial remodeling and indications of an mitochondrial unfolded protein response.
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Authors | Lauren M Sparks, Leanne M Redman, Kevin E Conley, Mary-Ellen Harper, Andrew Hodges, Alexey Eroshkin, Sheila R Costford, Meghan E Gabriel, Fanchao Yi, Cherie Shook, Heather H Cornnell, Eric Ravussin, Steven R Smith |
Journal | The Journal of clinical endocrinology and metabolism
(J Clin Endocrinol Metab)
Vol. 101
Issue 12
Pg. 4994-5003
(12 2016)
ISSN: 1945-7197 [Electronic] United States |
PMID | 27710240
(Publication Type: Clinical Trial, Phase II, Journal Article, Randomized Controlled Trial)
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Chemical References |
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Topics |
- Absorptiometry, Photon
- Adenosine Triphosphate
(metabolism)
- Adult
- Female
- Gene Expression Profiling
- Hormesis
- Humans
- Magnetic Resonance Spectroscopy
- Male
- Middle Aged
- Mitochondria, Muscle
(metabolism)
- Muscle, Skeletal
(metabolism)
- Oxidative Coupling
- Oxidative Stress
- Oxygen Consumption
- Sedentary Behavior
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