Idiopathic Parkinson's Disease (PD) is a major neurodegenerative disease affecting at least 1 million Americans, and the cellular cause of PD is not yet known with certainty. This proposal will explore further the central hypothesis that defects in mitochondrial electron transport chain (ETC) function are a major contributor to premature cell death in PD and will address four Specific Aims 1) define the pathophysiology of mitochondrial transition pore function, and how regulation of membrane potential and intracellular calcium signaling are altered in PD; 2) determine mechanisms of Bcl protein regulation in PD cybrids, and whether transfection with Bcl-overexpression vectors alters mitochondrial function and improves survival; 3) further define the interactions among MAPKinase signaling pathways and NFkappaBeta transcription factor in PD; and 4) characterize mitochondrial transition pore complexes isolated from human postmortem PD brain and compare their function to those isolated from control brain. This project will make use of state-of-the- art intracellular ion imaging technology, RT-PCR techniques, gene transfection strategies, and will develop cell-free systems to examine several inter-related hypotheses. Behind all of these laboratory experiments is a therapeutic imperative, which will be explored in cell and cell-free models. Because new data presented in this application supports the hypothesis of systemically increased oxidative stress in PD patients, exploring these events in an established cell model is even more compelling. This proposal will also compare findings in PD cybrids with those in SY5Y cells exposed to chronic rotenone treatment, a pharmacological cell-based model of complex I loss. Ultimately, the results from this proposal will establish the central importance of genetically acquired mitochondrial ETC dysfunction as an etiologic factor in sporadic PD. Paradigms for evaluating neuroprotective therapies will also be developed to allow targeted approaches to correcting consequences of increased oxidative stress in cells.

National Institute of Health (NIH)
National Institute of Neurological Disorders and Stroke (NINDS)
Research Project (R01)
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Study Section
Special Emphasis Panel (ZRG1-BDCN-3 (01))
Program Officer
Oliver, Eugene J
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University of Virginia
Schools of Medicine
United States
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Thiffault, Christine; Bennett Jr, James P (2005) Cyclical mitochondrial deltapsiM fluctuations linked to electron transport, F0F1 ATP-synthase and mitochondrial Na+/Ca+2 exchange are reduced in Alzheimer's disease cybrids. Mitochondrion 5:109-19
Onyango, Isaac G; Tuttle, Jeremy B; Bennett Jr, James P (2005) Altered intracellular signaling and reduced viability of Alzheimer's disease neuronal cybrids is reproduced by beta-amyloid peptide acting through receptor for advanced glycation end products (RAGE). Mol Cell Neurosci 29:333-43
Onyango, Isaac G; Tuttle, Jeremy B; Bennett Jr, James P (2005) Brain-derived growth factor and glial cell line-derived growth factor use distinct intracellular signaling pathways to protect PD cybrids from H2O2-induced neuronal death. Neurobiol Dis 20:141-54
Onyango, Isaac G; Bennett Jr, James P; Tuttle, Jeremy B (2005) Endogenous oxidative stress in sporadic Alzheimer's disease neuronal cybrids reduces viability by increasing apoptosis through pro-death signaling pathways and is mimicked by oxidant exposure of control cybrids. Neurobiol Dis 19:312-22
Onyango, Isaac G; Tuttle, Jeremy B; Bennett Jr, James P (2005) Activation of p38 and N-acetylcysteine-sensitive c-Jun NH2-terminal kinase signaling cascades is required for induction of apoptosis in Parkinson's disease cybrids. Mol Cell Neurosci 28:452-61
Khan, Shaharyar M; Bennett Jr, James P (2004) Development of mitochondrial gene replacement therapy. J Bioenerg Biomembr 36:387-93
Trimmer, Patricia A; Keeney, Paula M; Borland, M Kate et al. (2004) Mitochondrial abnormalities in cybrid cell models of sporadic Alzheimer's disease worsen with passage in culture. Neurobiol Dis 15:29-39
Kindler, Dean D; Thiffault, Christine; Solenski, Nina J et al. (2003) Neurotoxic nitric oxide rapidly depolarizes and permeabilizes mitochondria by dynamically opening the mitochondrial transition pore. Mol Cell Neurosci 23:559-73
Dennis, Jameel; Bennett Jr, James P (2003) Interactions among nitric oxide and Bcl-family proteins after MPP+ exposure of SH-SY5Y neural cells II: exogenous NO replicates MPP+ actions. J Neurosci Res 72:89-97
Brill 2nd, Louis B; Bennett Jr, James P (2003) Dependence on electron transport chain function and intracellular signaling of genomic responses in SH-SY5Y cells to the mitochondrial neurotoxin MPP(+). Exp Neurol 181:25-38

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