Abstract : The aim of our work is to study mechanisms of in situ regulation of respiration of permeabilized muscle cells in order to understand the relationship between regulation of oxidative phosphorylation, energy fluxes and structural organization of the cells.
We performed complete kinetic analysis of regulation of respiration in situ of permeabilized cardiac myocytes, supplemented with a system which modeling the effects of glycolysis. The mitochondria network structure was studied using confocal microscopy. Mechanisms of regulation of respiration and energy fluxes in vivo are system level properties. They depend on the complexity of cellular organization and intracellular interactions of mitochondria with cytoskeleton, intracellular MgATPases and cytoplasmic glycolytic system and mechanisms of phosphotransfer and feedback regulation via PCr/CK shuttle in the presence of highly selective restriction to the diffusion at the level of the outer mitochondrial membrane.
We applied this protocol to study the regulation of mitochondrial respiration in experimental and clinical studies. The investigation of cardiotoxic effect of doxorubicin showed that its mechanism is highly dependent on the loss of MtCK/OxPhos functional coupling.
Skeletal muscle dysfunction of patients with chronic obstructive pulmonary disease is characterized by a high affinity of oxidative phosphorylation for free ADP which decreases after endurance training and high affinity of MtCK for creatine which does not change significantly after training.