THE ROLE OF INNATE IMMUNITY IN THE RESPONSE TO INTRACORTICAL MICROELECTRODES by JOHN KARL HERMANN Submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy Dissertation Advisor: Dr. Jeffrey R. Capadona Department of Biomedical Engineering CASE WESTERN RESERVE UNIVERSITY August 2018 CASE WESTERN RESERVE UNIVERSITY SCHOOL OF GRADUATE STUDIES We hereby approve the dissertation of John Hermann, candidate for the degree of Doctor of Philosophy*. Jeffrey R. Capadona Research Advisor Abidemi B. Ajiboye Committee Chair Dawn M. Taylor Committee Member Dominique M. Durand Committee Member Nicholas P. Ziats Committee Member 4/25/2018 Date of Defense *We also certify that written approval has been obtained for any proprietary material contained therein. i Table of Contents List of Tables ..................................................................................................................... vi List of Figures .................................................................................................................. viii Acknowledgements ............................................................................................................ xi List of Abbreviations ....................................................................................................... xiv Abstract ............................................................................................................................... 1 Chapter 1 Specific Aims .................................................................................................... 3 Aim 1: Investigate the effect of genetic and therapeutic inhibition of CD14 on intracortical microelectrode performance and tissue integration. ................................... 5 Aim 2: Characterize the role of TLR2 and TLR4 in the neuroinflammatory response to intracortical microelectrodes. .......................................................................................... 6 Chapter 2 Introduction ....................................................................................................... 8 2.1 Applications of Neural Interfacing ............................................................................ 8 2.2 Neural Interfacing Methods .................................................................................... 10 2.3 Intracortical microelectrodes ................................................................................... 13 2.4 Failure of intracortical microelectrodes .................................................................. 18 2.5 Foreign body response to intracortical microelectrodes ......................................... 23 2.6 Interventions to mitigate biological failures ............................................................ 27 2.7 Studies linking neuroinflammation to electrode failure .......................................... 44 2.8 Innate Immunity ...................................................................................................... 50 ii 2.9 Toll-like Receptors and CD14 ................................................................................. 53 2.10 Toll-like Receptors and CD14 in Neurodegenerative disorders ........................... 64 2.11 TLRs/CD14 in the foreign body response to intracortical microelectrodes .......... 67 2.12 How to inhibit TLR2, TLR4, and CD14 ............................................................... 72 Chapter 3 Inhibition of the cluster of differentiation 14 innate immunity pathway with IAXO-101 improves chronic microelectrode performance*# .......................................... 79 3.1 Abstract ................................................................................................................... 79 3.2 Introduction ............................................................................................................. 80 3.3 Methods ................................................................................................................... 85 3.4 Results ..................................................................................................................... 95 3.5 Discussion ............................................................................................................. 112 3.6 Conclusions ........................................................................................................... 123 3.7 Acknowledgements ............................................................................................... 124 Chapter 4 The role of toll-like receptor 2 and 4 innate immunity pathways in intracortical microelectrode induced neuroinflammation. .................................................................. 125 4.1 Abstract ................................................................................................................. 125 4.2 Introduction ........................................................................................................... 126 4.3 Materials and methods .......................................................................................... 129 4.4 Results ................................................................................................................... 136 4.5 Discussion ............................................................................................................. 150 iii 4.6 Conclusions ........................................................................................................... 158 4.7 Acknowledgements ............................................................................................... 159 4.8 Funding.................................................................................................................. 159 Chapter 5 Conclusions and Future Directions ............................................................... 160 Appendix ......................................................................................................................... 168 Supporting Author Papers ............................................................................................... 169 Supporting Author Paper 1 Targeting CD14 on blood derived cells improves intracortical microelectrode performance* ......................................................................................... 170 6.1 Abstract ................................................................................................................. 170 6.2 Introduction ........................................................................................................... 171 6.3 Results ................................................................................................................... 174 6.4 Discussion ............................................................................................................. 182 6.5 Conclusion ............................................................................................................. 189 6.6 Methods ................................................................................................................. 189 6.7 Acknowledgements ............................................................................................... 199 Supporting Author Paper 2 Implantation of Neural Probes in the Brain Elicits Oxidative Stress* ............................................................................................................................. 200 7.1 Abstract ................................................................................................................. 200 7.2 Introduction ........................................................................................................... 201 7.3 Materials and Methods .......................................................................................... 205 iv 7.4 Results ................................................................................................................... 212 7.5 Discussion ............................................................................................................. 219 7.6 Conclusion ............................................................................................................. 223 7.7 Conflict of Interest Statement ............................................................................... 224 7.8 Authors and Contributors ...................................................................................... 224 7.9 Funding.................................................................................................................. 225 7.10 Acknowledgements ............................................................................................. 225 Supplemental Information .............................................................................................. 226 8.1 Supplemental information from Chapter 3 ............................................................ 226 8.2 Supplemental information for Supporting Author Paper 1 ................................... 230 Bibliography ................................................................................................................... 236 v List of Tables Table 1. Major types of interfaces with the brain with varying degrees of invasiveness. 12 Table 2. Summary of major pathogen associated molecular patterns (PAMPs) recognized by toll-like receptors (TLRs). ........................................................................................... 56 Table 3. Summary of major damage associated molecular patterns (DAMPs)