Modifiers of Beta-Amyloid Metabolism and Deposition in Mouse Models of Alzheimer’S Disease
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MODIFIERS OF BETA-AMYLOID METABOLISM AND DEPOSITION IN MOUSE MODELS OF ALZHEIMER’S DISEASE by STEFANIE SCHRUMP Submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy Dissertation Adviser: Bruce Lamb, Ph.D. Department of Genetics CASE WESTERN RESERVE UNIVERSITY August, 2011 CASE WESTERN RESERVE UNIVERSITY SCHOOL OF GRADUATE STUDIES We hereby approve the thesis/dissertation of Stefanie Elaine Schrump______________________________________ candidate for the Doctor of Philosophy degree *. (signed) Mitch Drumm_______________________________________ (chair of the committee) Bruce Lamb_________________________________________ Anna Mitchell_______________________________________ Gary Landreth_______________________________________ ___________________________________________________ (date) May 9, 2011____________ *We also certify that written approval has been obtained for any proprietary material contained therein. 2 Copyright © 2011 by Stefanie E. Schrump All rights reserved 3 This thesis is dedicated to my children, the greatest accomplishments of my life. 4 TABLE OF CONTENTS Chapter 1: Introduction and Research Aims………………………………….16 Introduction to Alzheimer’s Disease Alzheimer’s Disease Hallmarks Alzheimer’s Disease Epidemiology APP, Abeta and the Amyloid Hypothesis Mouse Models of Alzheimer’s Disease Research Aims Chapter 2: Gene-Environment Interactions Influence Beta-Amyloid Metabolism in Mice…………………………………………………..60 Abstract Introduction Materials and Methods Results Discussion Chapter 3: The Role of the Complement Protein C5 Signaling in Beta- Amyloid Deposition………………………………………………...117 Abstract Introduction Materials and Methods Results Discussion 5 Chapter 4: Genetic Background Differentially Influences Beta-Amyloid Metabolism and Deposition……………………………………….154 Abstract Introduction Materials and Methods Results Discussion Chapter 5: Summary and Future Directions…………………………………195 Summary Observation 1: Genetic background alters Aβ levels Observation 2: Genes and environment interact to alter Aβ levels Observation 3: Identification of chromosomal loci associated with altered Aβ levels Conclusions Bibliography…………………………………………………………………………209 6 LIST OF TABLES: Chapter 1: Table 1-1: Genes showing genome-wide significance in at least one GWAS……………………………………………………...52 Table 1-2: Current top nine genes, in addition to APOE, associated with Alzheimer’s disease based on meta-analysis of published association studies………………………………...53 Table 1-3: Selected examples of mouse models of Alzheimer’s disease………………………………………………………….58 Table 1-4: Summary of studies examining the effects of HF/HC diet on mouse models of AD………………………………………59 Chapter 2: Table 2-1: Genes exhibiting altered expression on HF/HC diets …………………………………………………………...103 Supplemental Table 2-1: 159 genes differentially expressed in HF/HC fed B6-R1.40 animals……………………………….112 Supplemental Table 2-2: 6 genes differentially expressed in HF/HC- fed 129-R1.40 animals……………………………………....116 7 LIST OF FIGURES Chapter 1: Figure 1-1: Genetic and environmental factors influence AD risk……………………………………………………………….50 Figure 1-2: Processing of the amyloid precursor protein (APP)……………………………………………………………54 Figure 1-3: The amyloid hypothesis………………………………..56 Chapter 2: Figure 2-1: Genetic background dependent effects of HF/HC diet on body weight, serum cholesterol and brain Aβ levels…..91 Figure 2-2: Correlation of brain Aβ levels with serum cholesterol in B6-R1.40 mice…………………………………………………93 Figure 2-3: Unaltered APP expression and processing in B6-R1.40 animals on HF/HC diet……………………………………….95 Figure 2-4: Similar brain Apoe levels in B6-R1.40 animals on the HF/HC and LF/LC diets……………………………….97 Figure 2-5: Unique brain gene expression profile in B6-R1.40 mice on the LF/LC and HF/HC diets……………………………….99 Figure 2-6: qRT-PCR verification of a subset of genes identified by microarray…………………………………………………….101 Supplemental Figure 2-1: Gender differences in body weight on HF/HC diet…………………………………………………….104 8 Supplemental Figure 2-2: Genetic background dependant effect of HF/HC diet on brain cholesterol…………………………….106 Supplemental Figure 2-3: Correlation of brain Aβ levels with body weight in individual R1.40 lines……………………………..108 Supplemental Figure 2-4: Correlation of brain Aβ with fasted serum cholesterol in R1.40 animals………………………………..110 Chapter 3: Figure 3-1: Region identified in QTL mapping correlates with B6.D2.2D congenic interval………………………………...138 Figure 3-2: B6.D2.2D congenic interval does not alter APP processing…………………………………………………….140 Figure 3-3: B6.D2.2D congenic interval on chromosome 2 does not alter steady state Aβ levels………………………………….142 Figure 3-4: D2 congenic interval of mouse chromosome 2 reduces Aβ deposition………………………………………………….144 Figure 3-5: Absence of the C5a receptor does not alter APP processing…………………………………………………….146 Figure 3-6: Absence of C5a receptor does not alter steady state Aβ levels…………………………………………………………..148 Figure 3-7: Absence of the C5a receptor reduces Aβ deposition in the R1.40 mouse model of AD……………………………...150 Figure 3-8: Absence of C5a receptor reduces Aβ deposition in the APPPS1 mouse model of AD……………………………….152 9 Chapter 4: Figure 4-1: Analysis of the congenic R1.40 mouse model of AD.……………………………………………………………..181 Figure 4-2: Steady state Aβ levels are increased in the B6.A-R1.40 consomic strains compared with the B6-R1.40 controls…………………………………………….183 Figure 4-3: Brain Aβ deposition reduced in the presence of A11 chromosome………………………………………………….185 Figure 4-4: APP processing is unaltered in the B6.A11-APPPS1 consomic animals…………………………………………….187 Figure 4-5: B6.D2.1D and B6.D2.7D congenic regions are not associated with reduced steady state Aβ levels…………..189 Figure 4-6: Aβ deposition reduced in B6.D2.1D congenic animals………………………………………………………...191 Figure 4-7: APP processing is unaltered in the B6.D2.1D congenic strain…………………………………………………………...193 10 ACKNOWLEDGEMENTS Being a student with the unique opportunity of starting graduate school in one lab and finishing in another, I have had an enriched graduate experience and have so many people to thank. I will begin by acknowledging people who have supported my scientific endeavors within the laboratory. First and foremost, I would like to thank my current advisor, Bruce Lamb, for taking me on as a graduate student mid-program, after my first mentor moved to Washington. His dedication to the fight against Alzheimer’s disease is inspirational. I am grateful for the opportunity to train with Bruce and will value him as a colleague throughout my scientific career. I would next like to thank Guixiang Xu, who has been an immeasurable help to me in the Lamb lab. I appreciate her scientific help as well as her loyal friendship. To Kiran Bhaskar, who has served as a mentor and a friend, you are always there to help, no matter the problem. I will miss our lively scientific discussions. To Davis Ryman, thank you for being an attentive and supportive baymate and friend. To all the other member of the Lamb lab, past and present who have provided assistance throughout my time in the lab, Brenda Mayne, Laura Kulnane, Karen Mann, Emily Lehman, Yuan Gao, Niki Kokako-Cochran, Megan Konerth, Yutaro Komuro, Nicole Maphis, Nick Varvel and Sungho Lee, I thank you. I’d also like to thank my first lab, where I spent the first two years of my graduate career and who really gave me the desire, confidence and opportunity to begin graduate school. To the bright and shining Terry Hassold, who was always ready with a pat on the back and a vote of confidence, you made 11 research fun, you made me want to make you proud, thank you. To his lovely wife Pat, who was always there to provide scientific support, thank you. You are the kindest couple in research and I am so grateful for the time we had. To the members of the Hunt/Hassold lab, especially Kara Koehler, Jodi Jackson, Martha Sujario and Petrice Brown, as well as to Brenda in the Willard lab and Michele in the Schwartz lab, I thank you for your support both scientific and moral. This was a really wonderful time in my scientific career, you are all greatly missed. To Joe Nadeau, the Chairman of the Genetics Department, I thank you for your kindness in making the decision to stay behind easy. To Hua Lou and Anne Matthew, the genetics graduate student advisors; I thank you for all of your assistance through the years. Thank you to all of the support staff in the Genetics Department at CWRU as well as in the Neuroscience Department at CCF, Clarice Young, Malana Bey, Dianne Austin, Michele Bey, Michele Yanick, Carol Haney and Eleanor Goldfarb who have been invaluable resources over the years. Finally, I would like to thank my committee members, Mitch Drumm, Gary Landreth, Anna Mitchell and Mark Palmert, for their guidance and support through the years. I’ve really cherished my time at the CWRU Genetics Department. Now I must acknowledge a number of people who have supported my graduate career in other ways. First, to my husband, Michael, he is always on my side, always believes I will persevere and always puts things in perspective for me, for his love and support I am forever thankful. To my children, my best accomplishments, I hope I have been a good role model for you and help you 12 realize you can accomplish your dreams. Coming home to my family has made every day a blessing. To my parents, Carl and Diane Schrump, who have been wonderful role models, balancing a happy family life with graduate careers in education, you have provided me with a lifetime of love and have always believed I could do anything, to you I am forever grateful. To my brother Tom who is always available for advice and support, thank you. A very special thanks to my sister Terri, who has helped me in so many ways I will never be able to repay you, your strength has been an inspiration. To my Mother-in-law and Father-in-law and all of my sister-in-laws and brother-in-laws, who are always there with warm words of encouragement, thank you. My family has been my greatest cheering section, with constant encouragement and an undying belief in me, without them I would never have been able to do this.