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Lemieux 2017 Sci Rep

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Lemieux H, Blier PU, Gnaiger E (2017) Remodeling pathway control of mitochondrial respiratory capacity by temperature in mouse heart: electron flow through the Q-junction in permeabilized fibers. Sci Rep s41598-017-02789-8.

ยป [www.nature.com/articles/s41598-017-02789-8]

Lemieux H, Blier PU, Gnaiger E (2017) Sci Rep

Abstract: Fuel substrate supply and oxidative phosphorylation are key determinants of muscle performance. Numerous studies of mammalian mitochondria are carried out (i) with substrate supply that limits electron flow, and (ii) far below physiological temperature. To analyze potentially implicated biases, we studied mitochondrial respiratory control in permeabilized mouse myocardial fibers using high-resolution respirometry. The capacity of oxidative phosphorylation at 37 ยฐC was nearly two-fold higher when fueled by physiological substrate combinations reconstituting tricarboxylic acid cycle function, compared with electron flow measured separately through NADH to Complex I or succinate to Complex II. The relative contribution of the NADH pathway to physiological respiratory capacity increased with a decrease in temperature from 37 to 25 ยบC. The apparent excess capacity of cytochrome c oxidase above physiological pathway capacity increased sharply under hypothermia due to limitation by NADH-linked dehydrogenases. This mechanism of mitochondrial respiratory control in the hypothermic mammalian heart is comparable to the pattern in ectotherm species, pointing towards NADH-linked mt-matrix dehydrogenases and the phosphorylation system rather than electron transfer complexes as the primary drivers of thermal sensitivity at low temperature. Delineating the link between stress and remodeling of oxidative phosphorylation is important for understanding metabolic perturbations in disease evolution and cardiac protection.

โ€ข Bioblast editor: Gnaiger E โ€ข O2k-Network Lab: AT Innsbruck Gnaiger E, AT Innsbruck OROBOROS, CA Rimouski Blier PU, CA Edmonton Lemieux H


Labels: MiParea: Respiration, Comparative MiP;environmental MiP 


Organism: Mouse  Tissue;cell: Heart  Preparation: Permeabilized tissue  Enzyme: Marker enzyme  Regulation: Temperature  Coupling state: LEAK, OXPHOS, ETS"ETS" is not in the list (LEAK, ROUTINE, OXPHOS, ET) of allowed values for the "Coupling states" property.  Pathway: N, S, NS  HRR: Oxygraph-2k 


Preprint

Lemieux H, Blier PU, Gnaiger E (2017) Remodeling pathway control of oxidative phosphorylation by temperature in the heart. bioRxiv doi: https://doi.org/10.1101/103457. - Lemieux 2017 bioRxiv Bioblast link