Greggio, ChiaraJha, PoojaKulkarni, Sameer S.Lagarrigue, SylvianeBroskey, Nicholas T.Boutant, MarieWang, XuAlonso, Sonia CondeOfori, EmmanuelAuwerx, JohanCanto, CarlesAmati, Francesca2017-03-272017-03-272017-03-27201710.1016/j.cmet.2016.11.004https://infoscience.epfl.ch/handle/20.500.14299/135878WOS:000396354400012Mitochondrial dysfunction is a hallmark of multiple metabolic complications. Physical activity is known to increase mitochondrial content in skeletal muscle, counteracting age-related decline in muscle function and protecting against metabolic and cardiovascular complications. Here, we investigated the effect of 4 months of exercise training on skeletal muscle mitochondria electron transport chain complexes and supercomplexes in 26 healthy, sedentary older adults. Exercise differentially modulated respiratory complexes. Complex I was the most upregulated complex and not stoichiometrically associated to the other complexes. In contrast to the other complexes, complex I was almost exclusively found assembled in supercomplexes in muscle mitochondria. Overall, supercomplex content was increased after exercise. Inparticular, complexes I, III, andIV wereredistributed to supercomplexes in the form of I+III2+IV. Taken together, our results provide the first evidence that exercise affects the stoichiometry of supercomplex formation in humans and thus reveal a novel adaptive mechanism for increased energy demand.text::journal::journal article::research article