PHENOTYPIC PATTERN OF ASTROCYTE ACTIVATION IN RESPONSE TO AGING AND ALZHEIMER’S-LIKE PATHOLOGY IN CHIIMPANZEES A thesis submitted To Kent State University in partial Fulfillment of the requirements for the Degree of Master of Arts by Emily LaRee Munger August, 2016 © Copyright All rights reserved Except for previously published materials Thesis written by Emily LaRee Munger B.S., Kent State University, 2014 M.A., Kent State University, 2016 Approved by Dr. Mary Ann Raghanti , Advisor Dr. Mary Ann Raghanti , Chair, Department of Anthropology Dr. James L. Blank , Dean, College of Arts and Sciences ii TABLE OF CONETENTS LIST OF FIGURES.................................................................................................................. v LIST OF TABLES.................................................................................................................... v LIST OF ABBREVIATIONS.................................................................................................. vi ACKNOWLEDGEMENTS..................................................................................................... vii CHAPTER 1 INTRODUCTION...................................................................................................... 1 1.1 Astrocytes’ Response to Pathology.......................................................... 3 Mild to Moderate Reactive Astrogliosis................................................... 5 Severe Diffuse Reactive Astrogliosis........................................................ 5 Severe Reactive Astrogliosis with Compact Glial Scar Formation.......... 6 1.2 Aging........................................................................................................ 7 1.3 Astrocytes and Alzheimer’s Disease........................................................ 7 Reactive Astrogliosis…............................................................................. 8 Astrocytes and Amyloid-β......................................................................... 9 Astrocytes and Tau.................................................................................... 11 Apolipoprotein E....................................................................................... 12 Neuroinflammation and Oxidative Stress................................................. 13 Blood Brain Barrier………....................................................................... 14 Disruption of Interlaminar Astrocytes...................................................... 15 1.4 The Great Apes and Alzheimer’s-like Pathology..................................... 16 1.5 Research Questions and Hypotheses........................................................ 19 CHAPTER 2 METHODS.................................................................................................................. 21 2.1 Specimens and Regions............................................................................. 21 2.2 Tissue Fixation.......................................................................................... 23 2.3 Sample Processing..................................................................................... 23 2.4 Immunohistochemistry.............................................................................. 24 2.5 Data Collection.......................................................................................... 25 2.6 Statistical Analysis.................................................................................... 27 Sex and Subfields................................................................................. 28 Age and Pathology.............................................................................. 29 Cortical Layers and Regions............................................................... 30 CHAPTER 3 RESULTS................................................................................................................... 32 iii 3.1 Qualitative Examination of GFAP-ir Astrocytes...................................... 32 3.2 Sex Differences......................................................................................... 35 3.3 Aging........................................................................................................ 35 3.4 Area Differences....................................................................................... 39 3.5 Comparison with Pathological Markers................................................... 42 CHAPTER 4 DISCUSSION............................................................................................................. 45 4.1 Age............................................................................................................ 45 4.2 Pathology.................................................................................................. 46 4.3 Sex Differences......................................................................................... 50 4.4 Conclusion................................................................................................ 52 4.5 Future Directions...................................................................................... 52 REFERENCES....................................................................................................................... 54 APPENDIX A........................................................................................................................ 81 APPENDIX B........................................................................................................................ 84 APPENDIX C........................................................................................................................ 86 APPENDIX D........................................................................................................................ 87 APPENDIX E........................................................................................................................ 90 APPENDIX F........................................................................................................................ 92 iv LIST OF FIGURES 1. Astrocyte subtypes in primates.......................................................................................... 3 2. Mild, moderate, and severe astrogliosis............................................................................. 7 3. GFAP-ir staining surrounding the vasculature in chimpanzees......................................... 15 4. Progression of AD pathogenesis........................................................................................ 23 5. Nissl-stained and GFAP immunostained sections of frontal cortex.................................. 26 6. Nissl-stained and GFAP immunostained sections of the MTG......................................... 27 7. Nissl-stained and GFAP immunostained sections of the HC............................................ 27 8. GFAP-ir staining................................................................................................................ 33 9. Severe inflammatory response of astrocytes in chimpanzees............................................ 34 10. Astrogliosis in response to amyloid and tau in the vasculature....................................... 34 11. Sex difference in GFAP-ir astrocyte soma volume in PFC layer III and V.................... 35 12. GFAP-ir density and soma volume by age in the HC...................................................... 36 13. GFAP-ir density and soma volume by age in the PFC.................................................... 37 14. GFAP-ir density and soma volume by age in the MTG.................................................. 38 15. GFAP-ir density by brain region..................................................................................... 39 16. GFAP-ir density and soma volume compared by cortical layer and subfield................. 41 17. Astrocyte density compared against total brain age score............................................... 42 18. Astrocyte density compared against tau brain age score................................................. 43 19. Astrocyte density compared against Aβ brain age score................................................. 44 LIST OF TABLES 1. Specimens quantified in the PFC, MTG, and HC.............................................................. 21 v LIST OF ABBREVIATIONS Aβ – β-amyloid AD – Alzheimer’s disease ANOVA – analysis of variance APP – amyloid precursor protein ApoE – apolipoprotein E gene BBB – blood brain barrier β-secretase – amyloid precursor protein cleavage enzyme 1 CAA – cerebral amyloid angiopathy CE – coefficient of error CNS – central nervous system GFAP – glial fibrillary acidic protein GFAP-ir – glial fibrillary acidic protein immunoreactivity GSH – glutathione HC – hippocampus LRP-1 – low-density lipoprotein receptor-related protein MCI – mild cognitive impairment mRNA – messenger RNA MTG – middle temple gyrus NFT’s – neurofibrillary tangles PFC – prefrontal cortex ROS – reactive oxygen species vi ACKNOWLEDGEMENTS I would first like to give many thanks to my advisor, Dr. Mary Ann Raghanti, whose constant support and advice has allowed me to succeed in this program. Your excitement for this field and your research motivates me to do my best. You have helped me to grow both personally and professionally and I could never thank you enough. I would also like to thank Dr. Gemma Casadesus-Smith and Dr. Richard Meindl for agreeing to be on my committee and for providing guidance and support throughout this process. To my office