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Krebs cycle metabolites and preferential succinate oxidation following neonatal hypoxic-ischemic brain injury in mice.

TitleKrebs cycle metabolites and preferential succinate oxidation following neonatal hypoxic-ischemic brain injury in mice.
Publication TypeJournal Article
Year of Publication2017
AuthorsSahni PV, Zhang J, Sosunov S, Galkin A, Niatsetskaya Z, Starkov A, Brookes PS, Ten VS
JournalPediatr Res
Date Published2017 Dec 06
ISSN1530-0447
Abstract

BackgroundReverse electron transport (RET) driven by the oxidation of succinate has been proposed as the mechanism of accelerated production of reactive oxygen species (ROS) in post-ischemic mitochondria. However, it remains unclear whether upon reperfusion, mitochondria preferentially oxidase succinate.MethodsNeonatal mice were subjected to Rice-Vannucci model of hypoxic-ischemic brain injury (HI) followed by assessment of Krebs cycle metabolites, mitochondrial substrate preference, and H2O2 generation rate in the ischemic brain.ResultsWhile brain mitochondria from control mice exhibited a rotenone-sensitive complex-I-dependent respiration, HI-brain mitochondria, at the initiation of reperfusion, demonstrated complex-II-dependent respiration, as rotenone minimally affected, but inhibition of complex-II ceased respiration. This was associated with a 30-fold increase of cerebral succinate concentration and significantly elevated H2O2 emission rate in HI-mice compared to controls. At 60 min of reperfusion, cerebral succinate content and the mitochondrial response to rotenone did not differ from that in controls.ConclusionThese data are the first ex vivo evidence, that at the initiation of reperfusion, brain mitochondria transiently shift their metabolism from complex-I-dependent oxidation of NADH toward complex II-linked oxidation of succinate. Our study provides a critical piece of support for existence of the RET-dependent mechanism of elevated ROS production in reperfusion.Pediatric Research advance online publication 6 December 2017. doi:10.1038/pr.2017.277.

DOI10.1038/pr.2017.277
Alternate JournalPediatr. Res.
PubMed ID29211056
Grant ListR01 HL071158 / HL / NHLBI NIH HHS / United States
R01 NS100850 / NS / NINDS NIH HHS / United States