Komlodi 2018b EBEC2018: Difference between revisions
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Our results highlight the importance of the availability of quinones in conjunction with the operation of Complex I in maintaining substrate-level phosphorylation during anoxia. | Our results highlight the importance of the availability of quinones in conjunction with the operation of Complex I in maintaining substrate-level phosphorylation during anoxia. | ||
|editor=[[Kandolf G]] | |editor=[[Kandolf G]] | ||
|mipnetlab= | |mipnetlab=AT Innsbruck Oroboros, UK Brighton Moore AL, HU Budapest Chinopoulos C | ||
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== Affiliations == | == Affiliations == | ||
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== References == | == References == | ||
:::# Kiss G, Konrad C, Doczi J, Starkov AA, Kawamata H, Manfredi G, Zhang SF, Gibson GE, Beal MF, Adam-Vizi V, Chinopoulos C (2013) The negative impact of ฮฑ-ketoglutarate dehydrogenase complex deficiency on matrix substrate-level phosphorylation. FASEB J 27:2392-406. | :::# Kiss G, Konrad C, Doczi J, Starkov AA, Kawamata H, Manfredi G, Zhang SF, Gibson GE, Beal MF, Adam-Vizi V, Chinopoulos C (2013) The negative impact of ฮฑ-ketoglutarate dehydrogenase complex deficiency on matrix substrate-level phosphorylation. FASEB J 27:2392-406. | ||
{{Labeling | |||
|area=Respiration | |||
|injuries=Permeability transition, Oxidative stress;RONS | |||
|organism=Mouse | |||
|tissues=Liver | |||
|preparations=Isolated mitochondria | |||
|topics=Q-junction effect | |||
|pathways=N | |||
|instruments=Oxygraph-2k, O2k-Fluorometer | |||
|additional=MitoFit 2022 NADH | |||
}} |
Latest revision as of 09:59, 3 May 2022
Endogenous quinones sustain NADH oxidation by Complex I during anoxia, supporting substrate-level phosphorylation in mouse liver mitochondria. |
Link: EBEC2018
Komlodi T, Ravasz D, Kitayev A, Hill C, Kiebish M, Doerrier C, Moore AL, Gnaiger E, Narain N, Seyfried TN, Adam-Vizi V, Chinopoulos C (2018)
Event: EBEC2018
Anoxia leads to over-reduction of mitochondrial coenzyme Q (Q, quinone) pools rendering Complex I unable to oxidize NADH, leading to a profound decrease in the matrix NAD+/NADH ratio. As a consequence, the function of matrix dehydrogenases is impaired. Yet, under certain anoxic conditions catabolism of metabolites converging through the ฮฑ-ketoglutarate dehydrogenase Complex (KGDHC) is known to occur, yielding succinyl-CoA, in turn supporting substrate-level phosphorylation substantiated by succinate-CoA ligase [1].
Mitochondrial respiration and NADH autofluorescence were measured simultaneously with the NextGen-O2k (Oroboros Instruments, Innsbruck, Austria), and the redox state of the Q-pool was detected with a three-electrode system implanted into the O2k (Oroboros Q2k).
We show that in isolated mouse liver mitochondria Complex I utilizes endogenous quinones oxidizing NADH during anoxia. Untargeted metabolomic analysis of matrix metabolites of mitochondria subjected to respiratory arrest due to anoxia and in the presence of specific inhibitors of respiratory complexes infer showed that NAD+ arising from Complex I is utilized by KGDHC yielding succinyl-CoA for succinate-CoA ligase, thus maintaining substrate-level phosphorylation during anoxia. Finally, by using custom-made 3D-printed plugs designed for standard fluorometric cuvettes, we show that under no conditions of respiratory arrest due to anoxia and/or pharmacological inhibition of the complexes did the mitochondria undergo swelling, which could potentially confound matrix metabolite estimations or bioenergetic parameters due to permeability transition. Our results highlight the importance of the availability of quinones in conjunction with the operation of Complex I in maintaining substrate-level phosphorylation during anoxia.
โข Bioblast editor: Kandolf G
โข O2k-Network Lab: AT Innsbruck Oroboros, UK Brighton Moore AL, HU Budapest Chinopoulos C
Affiliations
- Komlรณdi T(4), Ravasz D(1), Kitayev A(2), Hill C, Kiebish M(2), Doerrier C(4), Moore AL(3), Gnaiger E(4,5), Narain N(2), Seyfried TN(6), Adam-Vizi V(1), Chinopoulos C(1)
- Dept Medical Biochem, Semmelweis Univ, Budapest, Hungary
- BERG LLC, Framingham, MA, USA
- Dept Biochemistry Molecular Biology, School Life Sciences, Univ Sussex, Brighton, UK
- Oroboros Instruments, Innsbruck, Austria
- D. Swarovski Research Lab, Mitochondrial Physiology, Dept Visceral, Transplant Thoracic Surgery, Medical Univ Innsbruck, Austria
- Biology Dept, Boston College, Chestnut Hill, Boston, MA, USA
References
- Kiss G, Konrad C, Doczi J, Starkov AA, Kawamata H, Manfredi G, Zhang SF, Gibson GE, Beal MF, Adam-Vizi V, Chinopoulos C (2013) The negative impact of ฮฑ-ketoglutarate dehydrogenase complex deficiency on matrix substrate-level phosphorylation. FASEB J 27:2392-406.
Labels: MiParea: Respiration
Stress:Permeability transition, Oxidative stress;RONS Organism: Mouse Tissue;cell: Liver Preparation: Isolated mitochondria
Regulation: Q-junction effect
Pathway: N HRR: Oxygraph-2k, O2k-Fluorometer
MitoFit 2022 NADH