Loss of synaptic contacts, formation of neurofibrillary tangles and neuronal death are characteristic features of Alzheimer's disease. Oxidative stress causes neurodegeneration and affected neurons in AD demonstrate biochemical footprints of the past presence of oxidative stress. We reported that apolipoprotein E (apoE) regulates NO production, a key reactive oxygen/nitrogen species that causes oxidative stress. Our additional new data demonstrate that apolipoprotein E alters the neuronal uptake of L-arginine, the substrate* converted by nitric oxide synthase (NOS) into NO. We hypothesize that apoE regulates the function of cationic amino acid (CAT) transporters in an isoform specific manner, thereby altering the entry of L- arginine into the neuron which is then converted to NO by the action of NOS. We will test this hypothesis by measuring the functional activity of the CAT transporter in murine primary neuronal cultures exposed to human apoE and its isoforms and in primary neuronal cultures from mouse models expressing isoforms of human APOE and its gene products. Using semi-quantitative and quantitative measures, we will determine the effect of apoE and APOE genotype on CAT transporter mRNA and protein expression. Translation to NO production will be measured both directly by determining supernatant nitrite levels produced by NOS -containing neurons and indirectly by measuring indices of past-presence of NO (nitrotyrosine and hemeoxygenase 1). The validity of the mouse model will be tested by determining the apoE isoform dependency of arginine transporters in post-mortem human brain from individuals with and without previous clinical signs of dementia due to Alzheimer's disease.

Agency
National Institute of Health (NIH)
Institute
National Institute on Aging (NIA)
Type
Research Project (R01)
Project #
5R01AG019740-03
Application #
6721224
Study Section
Special Emphasis Panel (ZRG1-BDCN-3 (01))
Program Officer
Snyder, Stephen D
Project Start
2002-04-01
Project End
2007-03-30
Budget Start
2004-04-01
Budget End
2005-03-31
Support Year
3
Fiscal Year
2004
Total Cost
$365,750
Indirect Cost
Name
Duke University
Department
Internal Medicine/Medicine
Type
Schools of Medicine
DUNS #
044387793
City
Durham
State
NC
Country
United States
Zip Code
27705
Colton, Carol A; Wilcock, Donna M (2010) Assessing activation states in microglia. CNS Neurol Disord Drug Targets 9:174-91
Vitek, Michael P; Brown, Candice M; Colton, Carol A (2009) APOE genotype-specific differences in the innate immune response. Neurobiol Aging 30:1350-60
Wilcock, Donna M; Colton, Carol A (2009) Immunotherapy, vascular pathology, and microhemorrhages in transgenic mice. CNS Neurol Disord Drug Targets 8:50-64
Wilcock, Donna M; Gharkholonarehe, Nastaran; Van Nostrand, William E et al. (2009) Amyloid reduction by amyloid-beta vaccination also reduces mouse tau pathology and protects from neuron loss in two mouse models of Alzheimer's disease. J Neurosci 29:7957-65
Wilcock, D M; Vitek, M P; Colton, C A (2009) Vascular amyloid alters astrocytic water and potassium channels in mouse models and humans with Alzheimer's disease. Neuroscience 159:1055-69
Wilcock, Donna M; Lewis, Matthew R; Van Nostrand, William E et al. (2008) Progression of amyloid pathology to Alzheimer's disease pathology in an amyloid precursor protein transgenic mouse model by removal of nitric oxide synthase 2. J Neurosci 28:1537-45
Colton, Carol A; Wilcock, Donna M; Wink, David A et al. (2008) The effects of NOS2 gene deletion on mice expressing mutated human AbetaPP. J Alzheimers Dis 15:571-87
Hutchinson, D; Ho, V; Dodd, M et al. (2007) Quantitative measurement of postural sway in mouse models of human neurodegenerative disease. Neuroscience 148:825-32
Colton, C A; Vitek, M P; Wink, D A et al. (2006) NO synthase 2 (NOS2) deletion promotes multiple pathologies in a mouse model of Alzheimer's disease. Proc Natl Acad Sci U S A 103:12867-72
Bae, S Y; Xu, Q; Hutchinson, D et al. (2005) Y+ and y+ L arginine transporters in neuronal cells expressing tyrosine hydroxylase. Biochim Biophys Acta 1745:65-73

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