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J Cereb Blood Flow Metab. 2017 Dec;37(12):3649-3658. doi: 10.1177/0271678X17730242. Epub 2017 Sep 15.

Reverse electron transfer results in a loss of flavin from mitochondrial complex I: Potential mechanism for brain ischemia reperfusion injury.

Author information

1
1 School of Biological Sciences, Medical Biology Centre, 1596 Queen's University Belfast , Belfast, UK.
2
2 Feil Family Brain and Mind Research Institute, Weill Cornell Medicine, New York, NY, USA.
3
3 Department of Pediatrics, Columbia University, New York, NY, USA.

Abstract

Ischemic stroke is one of the most prevalent sources of disability in the world. The major brain tissue damage takes place upon the reperfusion of ischemic tissue. Energy failure due to alterations in mitochondrial metabolism and elevated production of reactive oxygen species (ROS) is one of the main causes of brain ischemia-reperfusion (IR) damage. Ischemia resulted in the accumulation of succinate in tissues, which favors the process of reverse electron transfer (RET) when a fraction of electrons derived from succinate is directed to mitochondrial complex I for the reduction of matrix NAD+. We demonstrate that in intact brain mitochondria oxidizing succinate, complex I became damaged and was not able to contribute to the physiological respiration. This process is associated with a decline in ROS release and a dissociation of the enzyme's flavin. This previously undescribed phenomenon represents the major molecular mechanism of injury in stroke and induction of oxidative stress after reperfusion. We also demonstrate that the origin of ROS during RET is flavin of mitochondrial complex I. Our study highlights a novel target for neuroprotection against IR brain injury and provides a sensitive biochemical marker for this process.

KEYWORDS:

Flavin; ischemia; mitochondria; stroke; succinate

PMID:
28914132
PMCID:
PMC5718331
DOI:
10.1177/0271678X17730242
[Indexed for MEDLINE]
Free PMC Article

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