Modulation of oxidative phosphorylation machinery signifies a prime mode of anti-ageing mechanism of calorie restriction in male rat liver mitochondria

Abstract

Mitochondria being the major source and target of reactive oxygen species (ROS) play a crucial role during ageing. We analyzed ageing and calorie restriction (CR)-induced changes in abundance of rat liver mitochondrial proteins to understand key aspects behind the age-retarding mechanism of CR. The combination of blue-native (BN) gel system with fluorescence Difference Gel Electrophoresis (DIGE) facilitated an efficient analysis of soluble and membrane proteins, existing as monomers or multi-protein assemblies. Changes in abundance of specific key subunits of respiratory chain complexes I, IV and V, critical for activity and/or assembly of the complexes were identified. CR lowered complex I assembly and complex IV activity, which is discussed as a molecular mechanism to minimize ROS production at mitochondria. Notably, the antioxidant system was found to be least affected. The GSH:GSSG couple could be depicted as a rapid mean to handle the fluctuations in ROS levels led by reversible metabolic shifts. We evaluated the relative significance of ROS generation against quenching. We also observed parallel and unidirectional changes as effect of ageing and CR, in subunits of ATP synthase, cytochrome P450 and glutathione S-transferase. This is the first report on such 'putatively hormetic' ageing-analogous effects of CR, besides the age-retarding ones.

Proteome analysis in the assessment of ageing

“…GRP78, protein-disulfide isomerase, and beta-actin) were also found to be affected. A more than two-fold reduction in ATP synthase was found, which is in agreement with the study performed by Dani et al (2010). Yet the increase in several subunits of complex I was more pronounced, which might result in an increased generation of superoxide anion radicals through electron leakage (Jastroch et al, 2010).…”

“…The mitochondrial proteome of the liver was investigated in male Wistar rats between 6 and 26 months of age using DIGE in a blue-native gel system combined with MALDI-TOF MS (Dani et al, 2010). Proteins involved in OXPHOS (complex I, IV and ATP synthase) and redox homeostasis/detoxification (catalase, microsomal glutathione S-transferase and cytochrome p450) were shown to be altered in older animals depending on a normal or calorie-restricted diet.…”

“…Hence, despite the increases in the other OXPHOS components, the decreases in the catalytic components of ATP synthase (F 1 ) suggested a decrease of OXPHOS-dependent ATP in the ageing liver. The detoxifying agent cytochrome p450 was reported to decrease during ageing (Dani et al, 2010). An age-related loss in cytochrome p450 activity was also observed in human subjects over the age of 70 compared to younger subjects (Sotaniemi et al, 1997).…”

Oxidative Stress, Aging and Mitochondrial Dysfunction in Liver Pathology

“…19 Furthermore, the mitochondrial complex I NDUFA12 subunit exhibits a significant 1.8-fold increase in abundance with age whereas complex IV subunits II, Va and VIb show a 1.45-fold increase in isolated mouse liver mitochondria. 20 Interestingly, the authors show that the catalytic F 1 complex beta subunit of complex V exhibits an age-dependent decrease in protein abundance whereas the F o subunit b of complex V shows a 1.25 increase in abundance with aging. In addition, aging also alters enzymes involved in fatty acid metabolism, 19 glycolysis and glycogen metabolism.…”

Biological Membranes Are Nanostructures that Require Internal Heat and Imaginary Temperature as New, Unique Physiological Parameters Related to Biological Catalysts

“…Changes in CYP-dependent monooxygenase and subunits of ATP synthase occur as a result of calorie restriction and aging [52]. Cyt b5 cooperates with a-tocopherol to protect membrane lipids from oxidation [53], but the level of cyt b5 in organs and tissues changes with age.…”