Huetter 2004 Biochem J
| Hütter E, Renner K, Pfister G, Stöckl P, Jansen-Dürr P, Gnaiger E (2004) Senescence-associated changes in respiration and oxidative phosphorylation in primary human fibroblasts. Biochem J 380: 919-928. |
Huetter E, Renner K, Pfister G, Stoeckl P, Jansen-Duerr P, Gnaiger E (2004) Biochem J
Abstract: Limitation of lifespan in replicative senescence is related to oxidative stress, which is probably both the cause and consequence of impaired mitochondrial respiratory function. The respiration of senescent human diploid fibroblasts was analysed by high-resolution respirometry. To rule out cell-cycle effects, proliferating and growth-arrested young fibroblasts were used as controls. Non-coupled respiration, as normalized to citrate synthase activity, remained unchanged, reflecting a constant mitochondrial electron transfer system (ETS) capacity. Oligomycin-inhibited LEAK respiration, however, was significantly increased in mitochondria of senescent cells, indicating a lower coupling of electron transfer with phosphorylation. In contrast, growth-arrested young fibroblasts exhibited a higher coupling control compared with proliferating controls. In intact cells, partial uncoupling (dyscoupling) may lead to either decreased oxidative ATP production or a compensatory increase in ROUTINE respiration. To distinguish between these alternatives, we subtracted oligomycin-inhibited respiration from ROUTINE respiration, which allowed us to determine the part of respiratory activity coupled with ATP production. Despite substantial differences in the respiratory control ratio, ranging from 4 to 11 in the different experimental groups, a fixed proportion of ETS capacity was maintained for coupled oxidative phosphorylation in all the experimental groups. This finding indicates that the senescent cells fully compensate for increased proton leakage by enhanced electron-transport activity in the ROUTINE state. These results provide a new insight into age-associated defects in mitochondrial function and compensatory mechanisms in intact cells. • Keywords: Aging, Coupling state, Mitochondria, Oxidative stress, Primary human fibroblast, Respiration, Senescence.
• O2k-Network Lab: AT_Innsbruck_Gnaiger E, AT_Innsbruck_Jansen-Duerr P
Labels:
Stress:RONS; Oxidative Stress"RONS; Oxidative Stress" is not in the list (Cell death, Cryopreservation, Ischemia-reperfusion, Permeability transition, Oxidative stress;RONS, Temperature, Hypoxia, Mitochondrial disease) of allowed values for the "Stress" property., Aging; Senescence"Aging; Senescence" is not in the list (Cell death, Cryopreservation, Ischemia-reperfusion, Permeability transition, Oxidative stress;RONS, Temperature, Hypoxia, Mitochondrial disease) of allowed values for the "Stress" property. Organism: Human Tissue;cell: Fibroblast Preparation: Intact Cell; Cultured; Primary"Intact Cell; Cultured; Primary" is not in the list (Intact organism, Intact organ, Permeabilized cells, Permeabilized tissue, Homogenate, Isolated mitochondria, SMP, Chloroplasts, Enzyme, Oxidase;biochemical oxidation, ...) of allowed values for the "Preparation" property., Permeabilized cells
Regulation: Respiration; OXPHOS; ETS Capacity"Respiration; OXPHOS; ETS Capacity" is not in the list (Aerobic glycolysis, ADP, ATP, ATP production, AMP, Calcium, Coupling efficiency;uncoupling, Cyt c, Flux control, Inhibitor, ...) of allowed values for the "Respiration and regulation" property., Coupling; Membrane Potential"Coupling; Membrane Potential" is not in the list (Aerobic glycolysis, ADP, ATP, ATP production, AMP, Calcium, Coupling efficiency;uncoupling, Cyt c, Flux control, Inhibitor, ...) of allowed values for the "Respiration and regulation" property., Mitochondrial Biogenesis; Mitochondrial Density"Mitochondrial Biogenesis; Mitochondrial Density" is not in the list (Aerobic glycolysis, ADP, ATP, ATP production, AMP, Calcium, Coupling efficiency;uncoupling, Cyt c, Flux control, Inhibitor, ...) of allowed values for the "Respiration and regulation" property.
HRR: Oxygraph-2k
Comment
- In the context of another study (MiP2005 Abstract), we compared respiration of intact and permeabilized fibroblasts with excellent results. Therefore, permeabilized cells provide an excellent model to extend mitochondrial studies of senescence. In fact, the fibroblasts in the present study were permeabilized for the JC1 experiments, to eliminate the confounding effect of the plasma membrane potential.
