The overarching theme of this proposal is that polymorphisms identified by recent Alzheimer's disease (AD) genome wide association studies biologically define rate-limiting steps in AD pathways. Hence, elucidating their mechanism of action will identify robust pharmacologic targets. Notably, a SNP with modest molecular actions may reduce AD risk by 10% but a drug that acts strongly at the same target may have a large effect on AD risk. This proposal will elucidate the mechanism of action of rs3865444 (rs444), an AD-associated SNP in CD33, and translate this mechanism into a proof of concept AD treatment. In our highly compelling preliminary results, we associate the AD-protective minor allele of rs444 with (i) a robust increase in the proportion of CD33 lacking exon 2 (D2-CD33) which appears critical to CD33 function. Large pharma have developed humanized monoclonal antibodies against CD33 for acute myeloid leukemia (AML); these antibodies and their derivatives have potential AD relevance as CD33 antagonists. This leads to our global hypothesis: Reduced CD33 function decreases AD risk whether CD33 inhibition is due to genetics or pharmacologic agents. To test our hypothesis, we will (i) Elucidate the mechanism underlying the CD33 AD SNP, (ii) Compare CD33 and D2- CD33 function, especially relative to AD pathogenic mechanisms, and (iii) Translate CD33 genetics into a novel AD therapeutic mimic. Overall, this focused proposal will develop our compelling mechanistic genetic results, elucidate the differences in D2-CD33 and CD33 function, and begin to translate these changes into an AD-preventive agent. In work beyond the scope of this focused proposal, we anticipate that these therapeutic agents will be tested in AD murine models that are transgenic for human CD33 and, eventually, humans.

Public Health Relevance

The significance of this proposal to public health is that we will identify the mechanism whereby a genetic factor modulates the risk of Alzheimer's disease. We will then perform studies to identify agents that target this mechanism as proof-of-concept pre- clinical Alzheimer's disease prevention studies.

Agency
National Institute of Health (NIH)
Institute
National Institute on Aging (NIA)
Type
Research Project (R01)
Project #
5R01AG045775-04
Application #
9251728
Study Section
Cellular and Molecular Biology of Neurodegeneration Study Section (CMND)
Program Officer
Refolo, Lorenzo
Project Start
2014-04-15
Project End
2018-03-31
Budget Start
2017-04-01
Budget End
2018-03-31
Support Year
4
Fiscal Year
2017
Total Cost
$276,741
Indirect Cost
$92,241
Name
University of Kentucky
Department
Physiology
Type
Schools of Medicine
DUNS #
939017877
City
Lexington
State
KY
Country
United States
Zip Code
40506
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Vasquez, Jared B; Simpson, James F; Harpole, Ryan et al. (2017) Alzheimer's Disease Genetics and ABCA7 Splicing. J Alzheimers Dis 59:633-641
De Rossi, Pierre; Buggia-Prévot, Virginie; Clayton, Benjamin L L et al. (2016) Predominant expression of Alzheimer's disease-associated BIN1 in mature oligodendrocytes and localization to white matter tracts. Mol Neurodegener 11:59
Malik, Manasi; Chiles 3rd, Joe; Xi, Hualin S et al. (2015) Genetics of CD33 in Alzheimer's disease and acute myeloid leukemia. Hum Mol Genet 24:3557-70
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Parikh, Ishita; Medway, Christopher; Younkin, Steven et al. (2014) An intronic PICALM polymorphism, rs588076, is associated with allelic expression of a PICALM isoform. Mol Neurodegener 9:32
Downer, Brian; Estus, Steven; Katsumata, Yuriko et al. (2014) Longitudinal trajectories of cholesterol from midlife through late life according to apolipoprotein E allele status. Int J Environ Res Public Health 11:10663-93
Parikh, Ishita; Fardo, David W; Estus, Steven (2014) Genetics of PICALM expression and Alzheimer's disease. PLoS One 9:e91242
Malik, Manasi; Simpson, James F; Parikh, Ishita et al. (2013) CD33 Alzheimer's risk-altering polymorphism, CD33 expression, and exon 2 splicing. J Neurosci 33:13320-5