Numerous studies have shown that Alpha-beta accumulation leads to synaptic dysfunction and loss of synapses. Synaptic Alpha-beta and Alpha-beta oligomers have been strongly implicated in the progression of AD. Recent studies have demonstrated that gamma-secretase forms an active complex at synapses. However, proteins modulating synaptic APP processing remain largely unknown. We have performed two proteomic screens in mouse brain lysates to identify proteins interacting with the ectodomains of APP and nicastrin. These screens have identified synaptotagmins (Syt) 1, 2, and 9 as strong binding partners of both APP and nicastrin. Syt1 and 9 also interact with the large loop of PSI (Project 3). Sytl, 2, and 9 are type I Ca2+-sensing synaptic vesicle membrane proteins and play a major role in distinct membrane fusion events for synaptic vesicle release. Our further co-IP, EM, and in situ PLA studies demonstrated that full-length Syts bind to APP in cells and mouse brains. GST pulldown assays confirmed specific binding of Sytl to a the region surrounding the KPI domain of APP. Our preliminary data also show that overexpression of Syts increases Alpha-beta generation and ratios, by perhaps inducing p- and/or gamma-secretase-mediated processing of APP. Syt expression also increases palmitoylated APP levels. Here, we will test the hypothesis that Sytl, 2, and 9 act as physiological modulators of APP processing in neurons. Specifically, we will further explore the regulation of Syt binding to APP, dissect the contribution of Syts to Alpha-beta generation in neuronal models and will ask whether Syts affect the neuronal functions of gamma-secretase. In addition, we will also analyze the effect of novel APP-specific gamma-secretase inhibitors (Project 1) and gamma-secretase modulators (Project 2) on the neuronal functions of gamma-secretase with particular focus on synaptic proteins, and on the processing of non-APP gamma-secretase substrates. These experiments are aimed at identifying compounds lacking adverse effects commonly associated with gamma-secretase inhibitors. Our project will contribute to the overall goal of the program project in providing mechanistic data that may serve in the development of novel p- or gamma-secretase-based strategies forthe prevention and treatment of Alzheimer's disease.

Public Health Relevance

We have recently found that three synaptotagmins bind to the beta-amyloid precursor protein, thereby increasing toxic beta-amyloid production. This proposal directly tests the mechanism of how synaptotagmins modulate beta-amyloid generation in neuronal models of Alzheimer's disease and may contribute to the development of novel strategies for the prevention and treatment of the disease.

Agency
National Institute of Health (NIH)
Institute
National Institute on Aging (NIA)
Type
Research Program Projects (P01)
Project #
5P01AG015379-17
Application #
8738551
Study Section
Special Emphasis Panel (ZAG1)
Project Start
Project End
Budget Start
2014-07-01
Budget End
2015-06-30
Support Year
17
Fiscal Year
2014
Total Cost
Indirect Cost
Name
Brigham and Women's Hospital
Department
Type
DUNS #
City
Boston
State
MA
Country
United States
Zip Code
02199
Jorfi, Mehdi; D'Avanzo, Carla; Kim, Doo Yeon et al. (2018) Three-Dimensional Models of the Human Brain Development and Diseases. Adv Healthc Mater 7:
Hartmann, Stephanie; Zheng, Fang; Kyncl, Michele C et al. (2018) ?-Secretase BACE1 Promotes Surface Expression and Function of Kv3.4 at Hippocampal Mossy Fiber Synapses. J Neurosci 38:3480-3494
Norambuena, Andrés; Wallrabe, Horst; Cao, Rui et al. (2018) A novel lysosome-to-mitochondria signaling pathway disrupted by amyloid-? oligomers. EMBO J 37:
Funane, Tsukasa; Hou, Steven S; Zoltowska, Katarzyna Marta et al. (2018) Selective plane illumination microscopy (SPIM) with time-domain fluorescence lifetime imaging microscopy (FLIM) for volumetric measurement of cleared mouse brain samples. Rev Sci Instrum 89:053705
Zoltowska, Katarzyna Marta; Maesako, Masato; Meier, Joshua et al. (2018) Novel interaction between Alzheimer's disease-related protein presenilin 1 and glutamate transporter 1. Sci Rep 8:8718
Park, Joseph; Wetzel, Isaac; Marriott, Ian et al. (2018) A 3D human triculture system modeling neurodegeneration and neuroinflammation in Alzheimer's disease. Nat Neurosci 21:941-951
Chatila, Zena K; Kim, Eunhee; Berlé, Clara et al. (2018) BACE1 Regulates Proliferation and Neuronal Differentiation of Newborn Cells in the Adult Hippocampus in Mice. eNeuro 5:
Zoltowska, Katarzyna Marta; Berezovska, Oksana (2018) Dynamic Nature of presenilin1/?-Secretase: Implication for Alzheimer's Disease Pathogenesis. Mol Neurobiol 55:2275-2284
Jorfi, Mehdi; D'Avanzo, Carla; Tanzi, Rudolph E et al. (2018) Human Neurospheroid Arrays for In Vitro Studies of Alzheimer's Disease. Sci Rep 8:2450
Gong, Yi; Sasidharan, Nikhil; Laheji, Fiza et al. (2017) Microglial dysfunction as a key pathological change in adrenomyeloneuropathy. Ann Neurol 82:813-827

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