It is clear that toxic oxidative stress in nigrostriatal dopaminergic neurons plays an important role in the pathogenesis of Parkinson's disease (PD). Since scientific evidence support mitochondria (mito) as a critical site for the induction of oxidative stress and cell death in PD, an attractive neuroprotective strategy would be to enrich nigrostriatal mito with the antioxidant, d-alpha-tocopherol (T). Accordingly, we contend that ineffective protection observed with vitamin E treatments in previous clinical and experimental investigations on PD resulted from the inability of these vitamin E treatments to enrich nigrostriatal mito with protective levels of T. In support of the critical role of mito T in the protection of cells against toxic oxidative stress, we have recently discovered that a single injection of d-alpha-tocopheryl succinate (TS) [but not T or d-alpha-tocopheryl acetate (TA)] as well as 7 days of dietary vitamin E (1400 IU TA/kg diet) result in dramatic T enrichment of hepatic mito membranes which completely prevented rotenone- and ferrous iron-induced necrotic cell death in rat hepatocytes. It is our working hypothesis that protection against toxic oxidative stress in experimental PD is dependent on the nigrostriatal enrichment of mito membranes with protective levels of T that attenuates mito reactive oxygen species (ROS) production and protects mito from ROS-mediated mito lipid, protein and DNA damage and these dopaminergic cells from death. This hypothesis will be tested both in vitro and in vivo using the oxidative insults: MPTP (or MPP+), rotenone or ferrous iron by: (1) determining the effect of T enrichment of mito membranes in dopaminergic cells on oxidative stress-induced mito ROS production, mito lipid, protein and DNA damage and apoptotic and necrotic cell death and (2) determining the ability of in vivo parenteral TS administration and chronic dietary vitamin E administration to enrich striatal mito membranes with T and protect against experimental PD. We believe that these novel studies will result in breakthrough discoveries that will clearly define the role of mito T in experimental PD as well as identify effective T treatment strategies for PD.

Agency
National Institute of Health (NIH)
Institute
National Institute of Neurological Disorders and Stroke (NINDS)
Type
Exploratory/Developmental Grants (R21)
Project #
1R21NS044202-01A1
Application #
6618801
Study Section
National Institute of Neurological Disorders and Stroke Initial Review Group (NSD)
Project Start
2003-03-01
Project End
2003-10-30
Budget Start
2003-03-01
Budget End
2003-10-30
Support Year
1
Fiscal Year
2003
Total Cost
$1,471
Indirect Cost
Name
Washington State University
Department
Pharmacology
Type
Schools of Pharmacy
DUNS #
041485301
City
Pullman
State
WA
Country
United States
Zip Code
99164
Fariss, Marc W; Chan, Catherine B; Patel, Manisha et al. (2005) Role of mitochondria in toxic oxidative stress. Mol Interv 5:94-111
Grammatopoulos, Tom N; Ahmadi, Ferogh; Jones, Susan M et al. (2005) Angiotensin II protects cultured midbrain dopaminergic neurons against rotenone-induced cell death. Brain Res 1045:64-71