Huntington's disease (HD) is an autosomal dominant neurodegenerative disorder that is caused by a pathological expansion of CAG repeats within the gene encoding for a 350 kD protein called huntingtin. This polyglutamine expansion within huntingtin is fundamental to the pathogenesis of HD, however the mechanisms by which this mutation causes the disease are unknown. One of the leading hypotheses of the etiology of HD is that mutant huntingtin directly or indirectly compromises mitochondrial function resulting in impairment of energy metabolism, increased oxidative damage and eventually neuronal death. Indeed, a marked reduction in the activity of mitochondrial complexes II and Ill, and to a lesser extent complex IV, has been detected in the striatum of subjects with HD. Further, an N-terminal fragment of mutant huntingtin has been localized to the nucleus, and there is data to suggest that mutant huntingtin can alter gene expression. Considering these and other findings, it is of fundamental importance to determine how mutant huntingtin affects mitochondrial function, and further how these changes modulate the cellular toxicity of mutant huntingtin. Our overall working hypothesis is that mutant huntingtin compromises the function of mitochondria which results in altered cellular functions and an increased sensitivity of the neurons to specific stressors.
The specific aims of this proposal are to: (1) test the hypothesis that mutant huntingtin impairs mitochondrial function which sensitizes the cells to specific stressors, (2) test the hypothesis that expression of mutant huntingtin results in selective alterations in the expression of mitochondrial proteins involved in energy metabolism and (3) test the hypothesis that impaired mitochondrial function compromises proteasome activity and this results in alterations in huntingtin processing. Further, we hypothesize that this process is exacerbated in cells expressing mutant huntingtin. For these studies we will establish immortalized striatal neurons that inducibly express wild type and mutant huntingtin constructs. These studies will provide critically important data on the effects of mutant huntingtin on mitochondrial function and energy metabolism and provide insight into the mechanisms by which mutant huntingtin impairs mitochondrial function and contributes to the neurodegenerative processes in HD.

Agency
National Institute of Health (NIH)
Institute
National Institute of Neurological Disorders and Stroke (NINDS)
Type
Research Project (R01)
Project #
7R01NS041744-06
Application #
7455482
Study Section
Special Emphasis Panel (ZRG1-MDCN-2 (01))
Program Officer
Sutherland, Margaret L
Project Start
2002-08-01
Project End
2008-07-31
Budget Start
2007-05-01
Budget End
2008-07-31
Support Year
6
Fiscal Year
2006
Total Cost
$74,657
Indirect Cost
Name
University of Rochester
Department
Anesthesiology
Type
Schools of Dentistry
DUNS #
041294109
City
Rochester
State
NY
Country
United States
Zip Code
14627
Quintanilla, Rodrigo A; Jin, Youngnam N; von Bernhardi, Rommy et al. (2013) Mitochondrial permeability transition pore induces mitochondria injury in Huntington disease. Mol Neurodegener 8:45
Jin, Youngnam N; Yu, Yanxun V; Gundemir, Soner et al. (2013) Impaired mitochondrial dynamics and Nrf2 signaling contribute to compromised responses to oxidative stress in striatal cells expressing full-length mutant huntingtin. PLoS One 8:e57932
Quintanilla, Rodrigo A; Dolan, Philip J; Jin, Youngnam N et al. (2012) Truncated tau and A* cooperatively impair mitochondria in primary neurons. Neurobiol Aging 33:619.e25-35
Jin, Youngnam N; Hwang, Woong Y; Jo, Chulman et al. (2012) Metabolic state determines sensitivity to cellular stress in Huntington disease: normalization by activation of PPARýý. PLoS One 7:e30406
Colak, Gozde; Filiano, Anthony J; Johnson, Gail V W (2011) The application of permanent middle cerebral artery ligation in the mouse. J Vis Exp :
Pritchard, Susanne M; Dolan, Philip J; Vitkus, Alisa et al. (2011) The toxicity of tau in Alzheimer disease: turnover, targets and potential therapeutics. J Cell Mol Med 15:1621-35
Colak, Gozde; Keillor, Jeffrey W; Johnson, Gail V W (2011) Cytosolic guanine nucledotide binding deficient form of transglutaminase 2 (R580a) potentiates cell death in oxygen glucose deprivation. PLoS One 6:e16665
Dolan, Philip J; Jin, Youngnam N; Hwang, Woong et al. (2011) Decreases in valosin-containing protein result in increased levels of tau phosphorylated at Ser262/356. FEBS Lett 585:3424-9
Dolan, Philip J; Johnson, Gail V W (2010) The role of tau kinases in Alzheimer's disease. Curr Opin Drug Discov Devel 13:595-603
Jin, Youngnam N; Johnson, Gail V W (2010) The interrelationship between mitochondrial dysfunction and transcriptional dysregulation in Huntington disease. J Bioenerg Biomembr 42:199-205

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