New and recurrent stroke is the third leading cause of death and the leading cause of long-term disability in the United States, yet no effective endogenous targets have been defined to prevent or attenuate stroke-induced brain injury. We have discovered that mitochondrial dihydrolipoamide dehydrogenase (DLDH) could be a target for chemical preconditioning against stroke injury. The objective of this application is thus to evaluate the neuroprotective efficacy of DLDH chemical preconditioning and delineate its underlying mechanisms. Our preliminary studies show that when rats were fed a 4-week diet supplemented with 5-methoxyindole-2- carboxylic acid (MICA), a specific and competitive DLDH inhibitor, brain infarction volume decreased by c. 60% after transient middle cerebral artery occlusion (tMCAO, 1 hr ischemia and 24 hr reperfusion). This result indicates that chronic DLDH inhibition by MICA affords robust cerebroprotection against stroke. Further studies of MICA-treated rats in the absence of stroke indicate that DLDH activity was lower than in control rats whilst NAD(P)H: quinone oxidoreductase-1 (NQO1) activity increased significantly in the MICA-treated rats. NQO1 is an inducible enzyme and its expression is activated by binding of the nuclear transcription factor E2-related factor 2 (Nrf2) to the antioxidant response element (ARE). Our preliminary studies also indicate that 4 weeks'MICA dietary administration did not affect food intake, body weight gain, blood glucose concentration, or mitochondrial respiratory complexes. These preliminary results support our central hypothesis that dietary inhibition of DLDH induces persistent cerebroprotection, affording enhanced recovery of cognitive and locomotor function after ischemic stroke, via activation of the Nrf2-ARE signaling cascade. The rationale for the proposed investigation is that identifying nontoxic, blood brain barrier-permeable chemical agents that afford brain protection from stroke, and defining the protective mechanisms, will foster development and clinical implementation of such agents to minimize death and disability in human victims of stroke. We plan to test our central hypothesis and, thereby, accomplish the objective of this application by addressing the following three Specific Aims: (1) To define the extent to which Nrf2 nuclear localization and NQO1 expression increase following MICA administration and tMCAO, (2) To measure the extent to which dietary preconditioning can produce persistent neuroprotection from stroke, and (3) To evaluate the effects of MICA diet and experimental stroke on neurobehavioral function and hippocampal synaptic plasticity measured as CA1 long-term potentiation (LTP). It is expected that the successfully completed study will provide novel strategies using DLDH as a target for stroke therapeutics.

Public Health Relevance

Stroke is a major cause of death and adult disability in the United States. Yet no effective endogenous targets have been defined to prevent or decrease ischemic brain injury. We have found that mitochondrial dihydrolipoamide dehydrogenase could be a suitable target for preconditioning or stroke tolerance. In particular, using rat as a model o stroke, we have found that dietary inhibition of DLDH for 4 weeks by a non- toxic inhibitor decreased brain infarction volume by about 60% after occlusion of middle cerebral artery for an hour. This project is to delineate the mechanisms of this dietary preconditioning phenotype to achieve our long term goal of exploiting DLDH as a novel therapeutic target for stroke.

National Institute of Health (NIH)
National Institute of Neurological Disorders and Stroke (NINDS)
Research Project (R01)
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Brain Injury and Neurovascular Pathologies Study Section (BINP)
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Bosetti, Francesca
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University of North Texas
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Fort Worth
United States
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Yan, Liang-Jun (2018) Reexploring 5-methoxyindole-2-carboxylic acid (MICA) as a potential antidiabetic agent. Diabetes Metab Syndr Obes 11:183-186
Wu, Jinzi; Jin, Zhen; Yang, Xiaorong et al. (2018) Post-ischemic administration of 5-methoxyindole-2-carboxylic acid at the onset of reperfusion affords neuroprotection against stroke injury by preserving mitochondrial function and attenuating oxidative stress. Biochem Biophys Res Commun 497:444-450
Yang, Xiaorong; Wu, Jinzi; Jing, Siqun et al. (2018) Mitochondrial protein sulfenation during aging in the rat brain. Biophys Rep 4:104-113
Yan, Liang-Jun (2018) Redox imbalance stress in diabetes mellitus: Role of the polyol pathway. Animal Model Exp Med 1:7-13
Luo, Xiaoting; Wu, Jinzi; Jin, Zhen et al. (2017) Non-Gradient Blue Native Polyacrylamide Gel Electrophoresis. Curr Protoc Protein Sci 87:19.29.1-19.29.12
Wu, Jinzi; Li, Rongrong; Li, Wenjun et al. (2017) Administration of 5-methoxyindole-2-carboxylic acid that potentially targets mitochondrial dihydrolipoamide dehydrogenase confers cerebral preconditioning against ischemic stroke injury. Free Radic Biol Med 113:244-254
Wu, Jinzi; Luo, Xiaoting; Thangthaeng, Nopporn et al. (2017) Pancreatic mitochondrial complex I exhibits aberrant hyperactivity in diabetes. Biochem Biophys Rep 11:119-129
Wu, Jinzi; Jin, Zhen; Yan, Liang-Jun (2017) Redox imbalance and mitochondrial abnormalities in the diabetic lung. Redox Biol 11:51-59
Jin, Zhen; Wu, Jinzi; Yan, Liang-Jun (2016) Chemical Conditioning as an Approach to Ischemic Stroke Tolerance: Mitochondria as the Target. Int J Mol Sci 17:351
Zheng, Hong; Wu, Jinzi; Jin, Zhen et al. (2016) Protein Modifications as Manifestations of Hyperglycemic Glucotoxicity in Diabetes and Its Complications. Biochem Insights 9:1-9

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