Hypoxic-ischemic encephalopathy is an important cause of long-term neurological morbidity in babies, children, and adults. How vulnerable the brain is to hypoxic-ischemic injury depends critically on postnatal maturation. Activation of neuronal glutamate receptors plays a major role in the excitotoxic neurodegeneration that characterizes acute brain injury from hypoxia-ischemia. The importance of postnatal maturation in determining vulnerability to hypoxia-ischemia highlights the need for a precise understanding of how postnatal maturation regulates the intracellular components of excitotoxicity. The major objective of this application is to characterize the precise developmental regulation of the calcium-dependent processes that lead to excitotoxic neurodegeneration. To achieve this objective, the following Specific Aims are proposed: (i) Identify how plasma membrane Na+/Ca2+ exchange, ER Ca2+ sequestration and mitochondrial Ca2+ sequestration change with postnatal development. Hippocampal neurons cultured from P 0-5, P 10-15, and P 18-25 rats will be exposed to a step increase in intracellular [Ca2+], and the contributions of the mitochondria, ER, and plasma membrane Na+/Ca2+ exchanger to the return of intracellular [Ca2+] to baseline will be measured. (ii) Assess the importance of developmental changes to these homeostatic mechanisms in determining vulnerability to NMDA. NMDA-induced loss in viability will be measured in neuronal cultures from rats of the same age groups in the presence and absence of specific blockade of these mechanisms. (iii) Identify the role of mitochondrial Ca2+ accumulation in the increased dissipation of mitochondrial membrane potential that occurs during postnatal development during NMDA exposure. NMDA effects on delta psi will be measured in neurons from the same 3 age groups and correlated with changes in mitochondrial [Ca2+], and cytosolic [Ca2+] in the presence and absence of mitochondrial Na+/Ca2+ exchange blockade. Isolated uniporter and Na+/Ca2+ exchanger activity will be measured in permeabilized neurons from P 0-5 and P 18-25 rats. (iv) Determine the extent to which alterations in mitochondrial Ca2+ accumulation contribute to the postnatal development of excitotoxic vulnerability. NMDA induced neuronal death will be measured in the presence and absence of blockade of the Na+/Ca2+ exchanger and of the mitochondrial transition pore.

Agency
National Institute of Health (NIH)
Institute
National Institute of Neurological Disorders and Stroke (NINDS)
Type
Research Project (R01)
Project #
5R01NS038547-05
Application #
6783277
Study Section
Special Emphasis Panel (ZRG1-MDCN-2 (01))
Program Officer
Hicks, Ramona R
Project Start
2000-08-15
Project End
2006-07-31
Budget Start
2004-08-01
Budget End
2006-07-31
Support Year
5
Fiscal Year
2004
Total Cost
$219,822
Indirect Cost
Name
University of Chicago
Department
Pediatrics
Type
Schools of Medicine
DUNS #
005421136
City
Chicago
State
IL
Country
United States
Zip Code
60637
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Plant, Leigh D; Dementieva, Irina S; Kollewe, Astrid et al. (2010) One SUMO is sufficient to silence the dimeric potassium channel K2P1. Proc Natl Acad Sci U S A 107:10743-8
Wang, Xue Qing; Deriy, Ludmila V; Foss, Sarah et al. (2006) CLC-3 channels modulate excitatory synaptic transmission in hippocampal neurons. Neuron 52:321-33
Li, Dongdong; Marks, Jeremy D; Schumacker, Paul T et al. (2005) Physiological hypoxia promotes survival of cultured cortical neurons. Eur J Neurosci 22:1319-26
Marks, Jeremy D; Boriboun, Chan; Wang, Janice (2005) Mitochondrial nitric oxide mediates decreased vulnerability of hippocampal neurons from immature animals to NMDA. J Neurosci 25:6561-75
Kuznetsov, Andrey; Bindokas, Vytautas P; Marks, Jeremy D et al. (2005) FRET-based voltage probes for confocal imaging: membrane potential oscillations throughout pancreatic islets. Am J Physiol Cell Physiol 289:C224-9
Kweon, Gi-Ryang; Marks, Jeremy D; Krencik, Robert et al. (2004) Distinct mechanisms of neurodegeneration induced by chronic complex I inhibition in dopaminergic and non-dopaminergic cells. J Biol Chem 279:51783-92