AXL receptor tyrosine kinase regulates Apolipoprotein E expression
department or school: Medicine, Faculty of
department or school: Pathology and Laboratory Medicine, Department of
data provider: DSpace
degree campus: UBCV
creator: Zhao, Wenchen
issued: 2019-09-30T00:00:00
issued: 2018
related degree: Master of Science - MSc
degree grantor: University of British Columbia
description: Alzheimer's disease (AD), the leading cause of dementia, is a chronic neurodegenerative disease. One of the hallmarks of AD is the accumulation of amyloid plaques in the brain. Apolipoprotein E (apoE), which carries lipids in the brain in the form of lipoproteins, plays an undisputed role in AD pathophysiology. The APOE gene is the most validated genetic risk factor for late onset AD, and has well-established associations with amyloid deposition and clearance from the brain. We and others have shown that lipidation of apoE can assist amyloid clearance, raising interest in augmenting apoE function as a proposed therapeutic strategy for AD. A high-throughput phenotypic screen was conducted using a CCF-STTG1 human astrocytoma cell line to identify small molecules that could upregulate apoE secretion. A subset of AXL receptor tyrosine kinase inhibitors, which we term AXL modulators were identified as positive hits. The objective of this thesis is to dissect the mechanism of action (MoA) by which AXL modulators upregulate apoE expression. We initially understood their dependency on AXL by treating AXL-/- CCF-STTG1 cells generated using CRISPR-Cas9 method with the lead compound. We then determined if Liver X Receptor (LXR) activity was required utilizing LXR knock-out (KO) mouse embryonic fibroblasts (MEF) cells. Immunoblotting analysis of AXL protein indicated the ability of AXL modulators to promote AXL receptor cleavage and stabilize the intracellular domain (ICD). To investigate the role of AXL-ICD in apoE homeostasis, various Axl variants, including WT AXL, kinase-dead AXL mutant, Axl-ICD, and AXL N-terminal fragment were stably reconstituted in AXL-/- CCF-STTG1 cells. ApoE baseline expression was significantly upregulated only upon reconstitution of ICD-containing AXL variants. In summary, AXL protein plays a significant role in apoE homeostasis through its intracellular domain.
aggregated CHO: https://circle.library.ubc.ca/rest/handle/2429/67274
note: AXL RECEPTOR TYROSINE KINASE REGULATES APOLIPOPROTEIN E EXPRESSION by Wenchen Zhao B.Sc., The University of British Columbia, 2016 A THESIS SUBMITTED IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF SCIENCE in THE FACULTY OF GRADUATE AND POSTDOCTORAL STUDIES (Pathology and Laboratory Medicine) THE UNIVERSITY OF BRITISH COLUMBIA (Vancouver) September 2018 © Wenchen Zhao, 2018 ii The following individuals certify that they have read, and recommend to the Faculty of Graduate and Postdoctoral Studies for acceptance, a thesis/dissertation entitled: AXL Receptor Tyrosine Kinase Regulates Apolipoprotein E Expression submitted by Wenchen Zhao in partial fulfillment of the requirements for the degree of Master of Science in Pathology and Laboratory Medicine Examining Committee: Cheryl Wellington, Pathology and Laboratory Medicine Supervisor Helene Cote, Pathology and Laboratory Medicine Supervisory Committee Member Haakon Nygaard, Experimental Medicine Supervisory Committee Member Neil Cashman, Pathology and Laboratory Medicine Additional Examiner Susanne Clee, Cellular and Physiological Sciences Additional Examiner Additional Supervisory Committee Members: Aly Karsan, Pathology and Laboratory Medicine Supervisory Committee Member Supervisory Committee Member iii Abstract Alzheimer's disease (AD), the leading cause of dementia, is a chronic neurodegenerative disease. One of the hallmarks of AD is the accumulation of amyloid plaques in the brain. Apolipoprotein E (apoE), which carries lipids in the brain in the form of lipoproteins, plays an undisputed role in AD pathophysiology. The APOE gene is the most validated genetic risk factor for late onset AD, and has well-established associations with amyloid deposition and clearance from the brain. We and others have shown that lipidation of apoE can assist amyloid clearance, raising interest in augmenting apoE function as a proposed therapeutic strategy for AD. A high-throughput phenotypic screen was conduct…
has type: Thesis/Dissertation
date issued: 2018-11
is shown at: 10.14288/1.0372324
language: eng
degree discipline: Pathology and Laboratory Medicine
provider: Vancouver : University of British Columbia Library
publisher: University of British Columbia
rights: Attribution-NonCommercial-NoDerivatives 4.0 International
rights URI: http://creativecommons.org/licenses/by-nc-nd/4.0/
scholar level: Graduate
type: Text
identifier URI: http://hdl.handle.net/2429/67274