THIS IS AN APPLICATION FOR AN INDEPENDENT SCIENTIST AWARD (K02) Recent results implicating cholesterol metabolism in the pathophysiology of Alzheimer's disease (AD) provide a rationale for studying the proteins involved in maintenance of cholesterol homeostasis. Four cytochrome P450 (P450) enzymes are known to catalyze the first and key steps in cholesterol degradation in different organs: P450 46A1 in the brain, P450 7A1 in the liver, P450 11A1 in steroidogenic tissues and the brain, and P450 27A1 in all other extrahepatic tissues. The long-term goals of this laboratory are: 1) to establish how the four enzymes that share <= 25% sequence identity bind the very same substrate, cholesterol, yet produce a different product, and 2) to determine the molecular basis for their very different catalytic efficiencies allowing P450 7A1 to metabolize 600 mg of cholesterol every day and P450 46A1 only 6-7 mg. The results will provide insight into how to modulate the activity of cholesterol-metabolizing P450s in vivo and thus maintain cholesterol at normal levels in the periphery and the brain. Our current GM62882 is focused on P450s 7A1 and 27A1, enzymes that are crucial for cholesterol catabolism outside the brain. In the Research Plan of this K02 we propose to expand our structure/function studies and investigate P450s 46A1 and 11A1, enzymes that regulate the elimination of excess cholesterol in the brain. The Career Development plan includes collaborative studies with investigators from the Alzheimer's Disease Research Center at Mount Sinai School of Medicine that will involve two techniques new to the P.I.'s research program. Gas chromatography-mass spectrometry will be used to quantify cholesterol metabolite levels in human brain samples of normal and AD-affected subjects, and immunocytochemistry to study the expression of P450s 46A1 and 11A1, as well as amyloid precursor and (3 proteins in the same brain samples. The new methodologies and collaborative studies will help in developing a new direction in the P.I.'s research program and foster application of the basic science knowledge to prevention and treatment of diseases associated with imbalances in cholesterol metabolism. If funded, the release time and salary support will significantly enhance the P.I.'s career in basic science research and make it more medically oriented.

Agency
National Institute of Health (NIH)
Institute
National Institute on Aging (NIA)
Type
Research Scientist Development Award - Research (K02)
Project #
5K02AG024336-02
Application #
7092133
Study Section
National Institute on Aging Initial Review Group (NIA)
Program Officer
Petanceska, Suzana
Project Start
2005-07-15
Project End
2010-06-30
Budget Start
2006-07-15
Budget End
2007-06-30
Support Year
2
Fiscal Year
2006
Total Cost
$102,281
Indirect Cost
Name
University of Texas Medical Br Galveston
Department
Pharmacology
Type
Schools of Medicine
DUNS #
800771149
City
Galveston
State
TX
Country
United States
Zip Code
77555
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Shafaati, Marjan; Marutle, Amelia; Pettersson, Hanna et al. (2011) Marked accumulation of 27-hydroxycholesterol in the brains of Alzheimer's patients with the Swedish APP 670/671 mutation. J Lipid Res 52:1004-10
Mast, Natalia; Annalora, Andrew J; Lodowski, David T et al. (2011) Structural basis for three-step sequential catalysis by the cholesterol side chain cleavage enzyme CYP11A1. J Biol Chem 286:5607-13
Mast, Natalia; Reem, Rachel; Bederman, Ilya et al. (2011) Cholestenoic Acid is an important elimination product of cholesterol in the retina: comparison of retinal cholesterol metabolism with that in the brain. Invest Ophthalmol Vis Sci 52:594-603
Liao, Wei-Li; Heo, Gun-Young; Dodder, Nathan G et al. (2011) Quantification of cholesterol-metabolizing P450s CYP27A1 and CYP46A1 in neural tissues reveals a lack of enzyme-product correlations in human retina but not human brain. J Proteome Res 10:241-8
Charvet, Casey; Liao, Wei-Li; Heo, Gun-Young et al. (2011) Isolevuglandins and mitochondrial enzymes in the retina: mass spectrometry detection of post-translational modification of sterol-metabolizing CYP27A1. J Biol Chem 286:20413-22
Heo, Gun-Young; Bederman, Ilya; Mast, Natalia et al. (2011) Conversion of 7-ketocholesterol to oxysterol metabolites by recombinant CYP27A1 and retinal pigment epithelial cells. J Lipid Res 52:1117-27
Shafaati, Marjan; Mast, Natalia; Beck, Olof et al. (2010) The antifungal drug voriconazole is an efficient inhibitor of brain cholesterol 24S-hydroxylase in vitro and in vivo. J Lipid Res 51:318-23
Mast, Natalia; Shafaati, Marjan; Zaman, Wahiduz et al. (2010) Marked variability in hepatic expression of cytochromes CYP7A1 and CYP27A1 as compared to cerebral CYP46A1. Lessons from a dietary study with omega 3 fatty acids in hamsters. Biochim Biophys Acta 1801:674-81
Liao, Wei-Li; Heo, Gun-Young; Dodder, Nathan G et al. (2010) Optimizing the conditions of a multiple reaction monitoring assay for membrane proteins: quantification of cytochrome P450 11A1 and adrenodoxin reductase in bovine adrenal cortex and retina. Anal Chem 82:5760-7

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