Ravasz 2024 Sci Rep
| Ravasz D, Bui D, Nazarian S, Pallag G, Karnok N, Roberts J, Marzullo BP, Tennant DA, Greenwood B, Kitayev A, Hill C, Komlódi T, Doerrier C, Cunatova K, Fernandez-Vizarra E, Gnaiger E, Kiebish MA, Raska A, Kolev K, Czumbel B, Narain NR, Seyfried TN, Chinopoulos C (2024) Residual Complex I activity and amphidirectional Complex II operation support glutamate catabolism through mtSLP in anoxia. Sci Rep 14:1729. https://doi.org/10.1038/s41598-024-51365-4 |
Ravasz D, Bui D, Nazarian S, Pallag G, Karnok N, Roberts J, Marzullo BP, Tennant DA, Greenwood B, Kitayev A, Hill C, Komlódi T, Doerrier C, Cunatova K, Fernandez-Vizarra E, Gnaiger E, Kiebish MA, Raska A, Kolev K, Czumbel B, Narain NR, Seyfried TN, Chinopoulos C (2024) Sci Rep
Abstract: Anoxia halts oxidative phosphorylation (OXPHOS) causing an accumulation of reduced compounds in the mitochondrial matrix which impedes dehydrogenases. By simultaneously measuring oxygen concentration, NADH autofluorescence, mitochondrial membrane potential and ubiquinone reduction extent in isolated mitochondria in real-time, we demonstrate that Complex I utilized endogenous quinones to oxidize NADH under acute anoxia. 13C metabolic tracing or untargeted analysis of metabolites extracted during anoxia in the presence or absence of site-specific inhibitors of the electron transfer system showed that NAD+ regenerated by Complex I is reduced by the 2-oxoglutarate dehydrogenase Complex yielding succinyl-CoA supporting mitochondrial substrate-level phosphorylation (mtSLP), releasing succinate. Complex II operated amphidirectionally during the anoxic event, providing quinones to Complex I and reducing fumarate to succinate. Our results highlight the importance of quinone provision to Complex I oxidizing NADH maintaining glutamate catabolism and mtSLP in the absence of OXPHOS.
• Bioblast editor: Gnaiger E • O2k-Network Lab: AT Innsbruck Oroboros, IT Padova Viscomi C, HU Budapest Tretter L, HU Budapest Chinopoulos C
Labels: MiParea: Respiration
Stress:Hypoxia Organism: Mouse Tissue;cell: Heart, Liver Preparation: Isolated mitochondria
Regulation: mt-Membrane potential, Redox state Coupling state: OXPHOS Pathway: N, S HRR: Oxygraph-2k, O2k-Fluorometer, NextGen-O2k
Rhodamine 123
