It has been shown that peripheral clearance of amyloid beta peptides reduces amyloid beta peptide levels in the brain through what has been termed a """"""""sink effect"""""""". We have exploited this """"""""sink effect"""""""" by showing that the peptidase neprilysin, when expressed peripherally on leukocytes reduced amyloid beta peptide levels in the brain of a hAPP transgenic mouse model of Alzheimer's disease. To obtain peripheral neprilysin expression we transplanted bone marrow stem cells transduced with lentivirus expressing neprilysin to a recipient hAPP transgenic mouse. We now propose to further develop peripheral expression of neprilysin as a therapeutic treatment for AD.
Two specific aims directed at further developing peripheral neprilysin expression, without the need for bone marrow transplantation, are proposed:
SPECIFIC AIM 1. To test the use of a single chain antibody-neprilysin (NEP) chimeric protein targeted to red blood cells to lower brain amyloid beta peptide levels. Chimeric proteins composed of a single chain antibody targeted to a mouse erythrocyte epitope fused with neprilysin will be used to produce erythrocyte bound neprilysin which will be tested for the ability to lower brain amyloid beta peptide levels.
SPECIFIC AIM 2. To test the use of a myristoylated-neprilysin to attach NEP to hematopoietic cells. We will generate a form of neprilysin in which a myristoyl-peptide is linked to the C-terminus. This myristoyl-NEP will be used to produce peripheral NEP by insertion into the plasma membrane of hematopoietic cells and tested for the ability to lower brain amyloid beta peptide levels. We have as an overall objective the translation of one of these methods to the testing of human subjects. PUBLIC HEALTH RELEVENCE: The focus of this proposal is to develope a new therapeutic approach for treating Alzheimer's disease. We propose to express the enzyme neprilysin on blood cells where it can degrade plasma amyloid beta peptides leading to a lowering of brain amyloid beta peptides which are known to play a major role in causing Alzheimer's disease.

Agency
National Institute of Health (NIH)
Institute
National Institute on Aging (NIA)
Type
Exploratory/Developmental Grants (R21)
Project #
1R21AG029907-01A2
Application #
7530025
Study Section
Special Emphasis Panel (ZRG1-MNPS-C (09))
Program Officer
Buckholtz, Neil
Project Start
2009-06-15
Project End
2011-05-31
Budget Start
2009-06-15
Budget End
2010-05-31
Support Year
1
Fiscal Year
2009
Total Cost
$166,823
Indirect Cost
Name
University of Kentucky
Department
Biochemistry
Type
Schools of Medicine
DUNS #
939017877
City
Lexington
State
KY
Country
United States
Zip Code
40506
Mateen, F J; Krecke, K; Younge, B R et al. (2010) Evolution of a tumor-like lesion in cerebroretinal vasculopathy and TREX1 mutation. Neurology 75:1211-3