Regulatory control of glutamate - induced neuronal superoxide production Project Summary/Abstract Glutamate excitotoxicity is a primary cause of cell death in stroke, brain trauma. Neuronal production of superoxide is necessary for excitotoxic cell death to occur. Glutamate-induced superoxide production has long been considered an inevitable, physical consequence of calcium influx and resulting mitochondrial dysfunction, but recent studies show that the superoxide is instead produced by the signaling enzyme, NADPH oxidase. Here we aim to delineate key regulatory steps in the signal transduction pathway linking neuronal glutamate receptor activation to NADPH oxidase activation, and the role of this process in local cell-to-cell propagation of excitotoxic injury. Preliminary studies suggest that key components of this pathway include the NR2B subunit of NMDA-type glutamate receptors, phosphoinositol-3-kinase (PI3K), PTEN, and phospholipase A2. The studies proposed here will evaluate the importance of each of these components using pharmacological, dominant negative, and genetic approaches. We also aim to identify mechanisms by which NADPH oxidase and mitochondria may interact in superoxide production. These studies will be performed using dissociated neuronal cultures, brain slices, and whole-animal experimental models. Successful completion of these studies will reconcile long-standing contradictions in this field, and will identify novel targets and mechanisms contributing to both acute and chronic neurological disorders. These studies will also further our understanding of the molecular framework for normal superoxide signaling between neurons, a process thought to modulate synaptic plasticity in brain. 1

Public Health Relevance

Glutamate - induced neuronal death is an important cause of neural injury in both acute-onset disorders such as stroke and trauma, and more chronic disorders such as amyotrophic lateral sclerosis and Alzheimer's disease. The reactive oxygen species, superoxide, is known to mediate glutamate-induced neuronal death. Studies proposed here will identify key steps leading from glutamate receptor activation to the production of superoxide, and thereby identify ways of blocking or modulating this important cell injury pathway.

Agency
National Institute of Health (NIH)
Institute
National Institute of Neurological Disorders and Stroke (NINDS)
Type
Research Project (R01)
Project #
5R01NS081149-02
Application #
8539111
Study Section
Neural Oxidative Metabolism and Death Study Section (NOMD)
Program Officer
Bosetti, Francesca
Project Start
2012-09-01
Project End
2017-05-31
Budget Start
2013-06-01
Budget End
2014-05-31
Support Year
2
Fiscal Year
2013
Total Cost
$320,863
Indirect Cost
$109,769
Name
Northern California Institute Research & Education
Department
Type
DUNS #
613338789
City
San Francisco
State
CA
Country
United States
Zip Code
94121
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Swanson, Raymond A (2014) Glucose, acid, and aspartate: Friends and foes of the axon. Ann Neurol 75:490-1
Knox, Renatta; Brennan-Minnella, Angela M; Lu, Fuxin et al. (2014) NR2B phosphorylation at tyrosine 1472 contributes to brain injury in a rodent model of neonatal hypoxia-ischemia. Stroke 45:3040-7
Lam, Tina I; Brennan-Minnella, Angela M; Won, Seok Joon et al. (2013) Intracellular pH reduction prevents excitotoxic and ischemic neuronal death by inhibiting NADPH oxidase. Proc Natl Acad Sci U S A 110:E4362-8
Brennan-Minnella, A M; Shen, Y; El-Benna, J et al. (2013) Phosphoinositide 3-kinase couples NMDA receptors to superoxide release in excitotoxic neuronal death. Cell Death Dis 4:e580