Tomar 2022 Biochim Biophys Acta Bioenerg
| Tomar N, Zhang X, Kandel SM, Sadri S, Yang C, Liang M, Audi SH, Cowley AW Jr, Dash RK (2022) Substrate-dependent differential regulation of mitochondrial bioenergetics in the heart and kidney cortex and outer medulla. https://doi.org/10.1016/j.bbabio.2021.148518 |
» Biochim Biophys Acta Bioenerg 1863:148518. PMID: 34864090 Open Access
Tomar N, Zhang X, Kandel SM, Sadri S, Yang C, Liang M, Audi SH, Cowley AW Jr, Dash RK (2022) Biochim Biophys Acta Bioenerg
Abstract: The kinetics and efficiency of mitochondrial oxidative phosphorylation (OxPhos) can depend on the choice of respiratory substrates. Furthermore, potential differences in this substrate dependency among different tissues are not well-understood. Here, we determined the effects of different substrates on the kinetics and efficiency of OxPhos in isolated mitochondria from the heart and kidney cortex and outer medulla (OM) of Sprague-Dawley rats. The substrates were pyruvate+malate, glutamate+malate, palmitoyl-carnitine+malate, alpha-ketoglutarate+malate, and succinate±rotenone at saturating concentrations. The kinetics of OxPhos were interrogated by measuring mitochondrial bioenergetics under different ADP perturbations. Results show that the kinetics and efficiency of OxPhos are highly dependent on the substrates used, and this dependency is distinctly different between heart and kidney. Heart mitochondria showed higher respiratory rates and OxPhos efficiencies for all substrates in comparison to kidney mitochondria. Cortex mitochondria respiratory rates were higher than OM mitochondria, but OM mitochondria OxPhos efficiencies were higher than cortex mitochondria. State 3 respiration was low in heart mitochondria with succinate but increased significantly in the presence of rotenone, unlike kidney mitochondria. Similar differences were observed in mitochondrial membrane potential. Differences in H2O2 emission in the presence of succinate±rotenone were observed in heart mitochondria and to a lesser extent in OM mitochondria, but not in cortex mitochondria. Bioenergetics and H2O2 emission data with succinate±rotenone indicate that oxaloacetate accumulation and reverse electron transfer may play a more prominent regulatory role in heart mitochondria than kidney mitochondria. These studies provide novel quantitative data demonstrating that the choice of respiratory substrates affects mitochondrial responses in a tissue-specific manner.
• Bioblast editor: Gnaiger E • O2k-Network Lab: US WI Milwaukee Dash RK
On terminology
- For harmonization of terminology on respiratory states and rates, see
- Gnaiger E et al ― MitoEAGLE Task Group (2020) Mitochondrial physiology. Bioenerg Commun 2020.1. https://doi.org/10.26124/bec:2020-0001.v1
- For harmonization of terminology on respiratory states and rates, see
Labels:
Outdated terminology
Labels: MiParea: Respiration
Stress:Oxidative stress;RONS Organism: Rat Tissue;cell: Heart, Kidney Preparation: Isolated mitochondria
Regulation: ADP, Inhibitor, mt-Membrane potential Coupling state: LEAK, OXPHOS, ET Pathway: F, N, S HRR: Oxygraph-2k
