ApoE receptors mediate many of the functions of apoE in the CNS;including endocytosis of lipoproteins, activation of kinase signaling pathways, and modulation of synaptic signaling and glial activation. One important aspect of apoE receptor biology is its shedding from the cell via regulated cleavage mechanisms. In this project, we will focus on one of these apoE receptors, ApoER2.
In Aim 1, we will test how proteolytic enzymes generate soluble receptors and cytoplasmic fragments, analyzing ADAMs and BACE. We will determine the mechanism of these cleavages, testing whether they are altered by the alternatively spliced O- linked glycosylation domain of ApoER2 and inhibited by the endogenous metalloproteinase inhibitor, TIMP-3. We hypothesize that the proteases responsible for APR cleavage also act on apoE receptors.
In Aim 2, we will focus on the regulation of these cleavage events. We will test how cytoplasmic adaptor proteins (FE65, Dab-1, SNX-17), influence trafficking of ApoER2, and how ligand binding (specifically apoE isoforms) affect receptor metabolism. We will examine the role shedding plays in the functions of ApoER2 in endocytosis and signaling, inlcuding mechanisms of neurotoxicity.
In Aim 3, we will test how secreted apoE receptors are cleared, examining several possible mediators of endocytosis. Through these three aims, we will define the production, function, and clearance of soluble ApoER2, and how the shedding process affects the functions of full-length ApoER2.
In Aim 4, we will examine the connections between ApoER2 and APP, using primary neurons and genetically modified mice. We will test how ligands (apoE-lipoproteins) affect ApoER2 proteolysis in vivo, and how soluble and full length ApoER2 affect AH plaque formation. We hypothesizethat because APP and apoE receptors share ligands, adaptor proteins, and proteolytic pathways, alteration of receptors such as ApoER2 have important effects on APP trafficking and proteolysis in vivo. We will work in concert with the other projects to progress each of these aims: Project 1for understanding how physiologically relevant forms of human apoE isoforms affect ApoER2 function including neurotoxicity; Project 2 for analysis of receptor splice variants;Project 3 for analysis of ApoER2 trafficking and processing; and Project 5 for determining the effects of ApoER2 on neuronal signaling and APP processing in vivo. Overall, these studies will examine the functional effects of apoE isoforms via ApoER2 in the CNS.

Agency
National Institute of Health (NIH)
Institute
National Institute on Aging (NIA)
Type
Research Program Projects (P01)
Project #
5P01AG030128-05
Application #
8500095
Study Section
Special Emphasis Panel (ZAG1-ZIJ-4)
Project Start
Project End
Budget Start
2013-07-01
Budget End
2014-06-30
Support Year
5
Fiscal Year
2013
Total Cost
$206,457
Indirect Cost
Name
University of Illinois at Chicago
Department
Type
DUNS #
098987217
City
Chicago
State
IL
Country
United States
Zip Code
60612
Luo, Jia; Lee, Sue H; VandeVrede, Lawren et al. (2016) A multifunctional therapeutic approach to disease modification in multiple familial mouse models and a novel sporadic model of Alzheimer's disease. Mol Neurodegener 11:35
DiBattista, Amanda M; Dumanis, Sonya B; Newman, Joshua et al. (2016) Identification and modification of amyloid-independent phenotypes of APOE4 mice. Exp Neurol 280:97-105
Cacciottolo, Mafalda; Christensen, Amy; Moser, Alexandra et al. (2016) The APOE4 allele shows opposite sex bias in microbleeds and Alzheimer's disease of humans and mice. Neurobiol Aging 37:47-57
Fu, Yuan; Zhao, Jing; Atagi, Yuka et al. (2016) Apolipoprotein E lipoprotein particles inhibit amyloid-β uptake through cell surface heparan sulphate proteoglycan. Mol Neurodegener 11:37
Tai, Leon M; Thomas, Riya; Marottoli, Felecia M et al. (2016) The role of APOE in cerebrovascular dysfunction. Acta Neuropathol 131:709-23
Teter, Bruce; LaDu, Mary Jo; Sullivan, Patrick M et al. (2016) Apolipoprotein E isotype-dependent modulation of microRNA-146a in plasma and brain. Neuroreport 27:791-5
Yang, Longyu; Liu, Chia-Chen; Zheng, Honghua et al. (2016) LRP1 modulates the microglial immune response via regulation of JNK and NF-κB signaling pathways. J Neuroinflammation 13:304
Casey, Caroline S; Atagi, Yuka; Yamazaki, Yu et al. (2015) Apolipoprotein E Inhibits Cerebrovascular Pericyte Mobility through a RhoA Protein-mediated Pathway. J Biol Chem 290:14208-17
Zhong, Li; Chen, Xiao-Fen; Zhang, Zhen-Lian et al. (2015) DAP12 Stabilizes the C-terminal Fragment of the Triggering Receptor Expressed on Myeloid Cells-2 (TREM2) and Protects against LPS-induced Pro-inflammatory Response. J Biol Chem 290:15866-77
Liu, De-shan; Pan, Xiao-dong; Zhang, Jing et al. (2015) APOE4 enhances age-dependent decline in cognitive function by down-regulating an NMDA receptor pathway in EFAD-Tg mice. Mol Neurodegener 10:7

Showing the most recent 10 out of 139 publications