The long-term objective of this study is to understand the biological significance of oxidative modification of neprilysin on amyloid deposition in aging and Alzheimer's disease (AD). Amyloid deposition in the brain parenchyma and in vessels is a common phenomenon with advanced age and one of the diagnostic hallmarks for AD. Two possible explanations for excessive beta-amyloid (AB) deposition in aging and AD brains are overproduction and decreased degradation. Although the mechanisms involved in AB production have been extensively studied and the excessive production of AB has been confirmed to play a critical role in the pathogenesis of familial AD cases, there is little evidence so far to suggest that increased brain AB production is important in aging and sporadic AD. Recently, the role of AB degradation has been increasingly studied and several enzymes have been described with a range of abilities to degrade AB. Among them, neprilysin (NEP) has been considered by some a pivotal enzyme for AB degradation. Previous studies have shown that decreased NEP may contribute to the accumulation of AB in AD. Recent data from our group indicated that brain NEP is subject to oxidative modification in both AD and aging. To understand the biological significance of oxidized-NEP it is very important to know if oxidization decreases NEP enzymatic activity. It is also important to know the HNE modification site(s) of NEP to design therapeutic reagents that can block oxidative modification of NEP. Our working hypothesis is that initial amyloid accumulation will lead to HNE production with progressive inhibitory NEP, starting a feed-forward cycle of increasing amyloid accumulation, oxidative stress, and NEP inhibition. To test this hypothesis, as initial steps we propose three specific aims in this RO3 proposal: 1. To determine if human NEP expressed in cultured cells can be modified by exogenous HNE or endogenous HNE induced by synthetic AB; 2. To discover if HNE-modified NEP expressed in cultured cells has decreased enzymatic activity. 3. To identify critical HNE-modification sites which alter NEP activity. Our goal through this RO3 mechanism is to develop enough preliminary data for a future RO1 application that will further explore this hypothesis in animal models and in humans. ? ? ?

Agency
National Institute of Health (NIH)
Institute
National Institute on Aging (NIA)
Type
Small Research Grants (R03)
Project #
5R03AG025722-02
Application #
7273587
Study Section
Special Emphasis Panel (ZRG1-NDBG-A (09))
Program Officer
Snyder, Stephen D
Project Start
2006-09-01
Project End
2008-08-31
Budget Start
2007-09-01
Budget End
2008-08-31
Support Year
2
Fiscal Year
2007
Total Cost
$62,804
Indirect Cost
Name
University of Wisconsin Madison
Department
Pathology
Type
Schools of Medicine
DUNS #
161202122
City
Madison
State
WI
Country
United States
Zip Code
53715
Zhang, Ji; Wang, Suqing; Huang, Wei et al. (2016) Tissue Transglutaminase and Its Product Isopeptide Are Increased in Alzheimer's Disease and APPswe/PS1dE9 Double Transgenic Mice Brains. Mol Neurobiol 53:5066-78
Zhou, Li; Wei, Chunsheng; Huang, Wei et al. (2013) Distinct subcellular patterns of neprilysin protein and activity in the brains of Alzheimer's disease patients, transgenic mice and cultured human neuronal cells. Am J Transl Res 5:608-21
Shen, Jiao-Ning; Wang, Deng-Shun; Wang, Rui (2012) The protection of acetylcholinesterase inhibitor on ?-amyloid-induced the injury of neurite outgrowth via regulating axon guidance related genes expression in neuronal cells. Int J Clin Exp Pathol 5:900-13
Wang, Rui; Malter, James S; Wang, Deng-Shun (2010) N-acetylcysteine prevents 4-hydroxynonenal- and amyloid-beta-induced modification and inactivation of neprilysin in SH-SY5Y cells. J Alzheimers Dis 19:179-89
Wang, Suqing; Wang, Rui; Chen, Lang et al. (2010) Expression and functional profiling of neprilysin, insulin-degrading enzyme, and endothelin-converting enzyme in prospectively studied elderly and Alzheimer's brain. J Neurochem 115:47-57
Wang, Rui; Wang, Suqing; Malter, James S et al. (2009) Effects of 4-hydroxy-nonenal and Amyloid-beta on expression and activity of endothelin converting enzyme and insulin degrading enzyme in SH-SY5Y cells. J Alzheimers Dis 17:489-501
Wang, Rui; Wang, Suqing; Malter, James S et al. (2009) Effects of HNE-modification induced by Abeta on neprilysin expression and activity in SH-SY5Y cells. J Neurochem 108:1072-82
Wang, Suqing; Simon, Brook P; Bennett, David A et al. (2007) The significance of Pin1 in the development of Alzheimer's disease. J Alzheimers Dis 11:13-23