Our laboratory has shown that systemic inhibition of mitochondrial complex I with rotenone reproduces in rats and monkeys many features of PD, including dopaminergic degeneration, Lewy body and neurite (alpha-synuclein) pathology, DJ-i modification and translocation to mitochondria, and impairment of the ubiquitin-proteasome system. Most recently, we have found that there is iron deposition in substantia nigra of rotenone treated rats and monkeys, which appears identical to that seen in PD brains. In this model, transferrin (Tf) becomes oxidized (at Cys26o) and accumulates in nigral dopaminergic neurons. In collaboration with Charleen Chu, director of the Neuropathology Core, Greenamyre has found a similar - previously undescribed - accumulation of transferrin in nigral neurons in human postmortem specimens from PD cases. Additionally, he has found that transferrin receptor 2 (TfR2): (i) has a mitochondrial targeting sequence;(ii) is localized, in part, in mitochondria;and (iii) protein is selectively expressed in nigral dopamine neurons in rats.
Aim i : We will determine the sequence of cell types that accumulate iron after rotenone using the in vivo model and organotypic midbrain slice cultures, and we vAW ultimately assess this in human postmortem specimens across Braak staging.
Aim 2 : We will characterize (i) the oxidation state and distributions of Tf and TfR2 in the rotenone brain, (ii) the functional consequences of Tf oxidation, and (iii) ultimately, the distributions and oxidation states of these proteins in human specimens.
Aim 3 : We will assess the functional role of TfR2 by overexpressing or silencing the TfR2 gene under basal conditions and with rotenone treatment. Outcomes to be measured include: aspects of iron homeostasis, oxidative stress, a-synuclein/cytochrome c interactions, activation of cell death and protective mechanisms and cell viability.
Aim 4 : Lastly, we will manipulate - via viral-mediated gene transfer - proteins that regulate or chelate iron. We will look at the effects of manipulating ferritin and frataxin on rotenone-induced toxicity. We believe this project will elucidate (i) the mechanisms by which iron accumulates in PD and (ii) its role in PD pathogenesis.

Agency
National Institute of Health (NIH)
Institute
National Institute of Neurological Disorders and Stroke (NINDS)
Type
Research Program Projects (P01)
Project #
5P01NS059806-04
Application #
8378712
Study Section
National Institute of Neurological Disorders and Stroke Initial Review Group (NSD)
Project Start
Project End
Budget Start
2012-07-01
Budget End
2013-06-30
Support Year
4
Fiscal Year
2012
Total Cost
$250,305
Indirect Cost
$82,206
Name
University of Pittsburgh
Department
Type
DUNS #
004514360
City
Pittsburgh
State
PA
Country
United States
Zip Code
15213
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Wang, Jiayin; Shi, Yejie; Zhang, Lili et al. (2014) Omega-3 polyunsaturated fatty acids enhance cerebral angiogenesis and provide long-term protection after stroke. Neurobiol Dis 68:91-103
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