A ROLE FOR THE NLR FAMILY MEMBERS NLRC4 AND NLRP3 IN ASTROCYTIC INFLAMMASOME ACTIVATION AND ASTROGLIOSIS Leslie C. Freeman A dissertation submitted to the faculty of the University of North Carolina at Chapel Hill in partial fulfillment of the requirements for the degree of Doctor of Philosophy in the Curriculum of Genetics and Molecular Biology. Chapel Hill 2016 Approved by: Jenny P. Y. Ting Glenn K. Matsushima Beverly H. Koller Silva S. Markovic-Plese Pauline. Kay Lund ©2016 Leslie C. Freeman ALL RIGHTS RESERVED ii ABSTRACT Leslie C. Freeman: A Role for the NLR Family Members NLRC4 and NLRP3 in Astrocytic Inflammasome Activation and Astrogliosis (Under the direction of Jenny P.Y. Ting) The inflammasome is implicated in many inflammatory diseases but has been primarily studied in the macrophage-myeloid lineage. Here we demonstrate a physiologic role for nucleotide-binding domain, leucine-rich repeat, CARD domain containing 4 (NLRC4) in brain astrocytes. NLRC4 has been primarily studied in the context of gram-negative bacteria, where it is required for the maturation of pro-caspase-1 to active caspase-1. We show the heightened expression of NLRC4 protein in astrocytes in a cuprizone model of neuroinflammation and demyelination as well as human multiple sclerotic brains. Similar to macrophages, NLRC4 in astrocytes is required for inflammasome activation by its known agonist, flagellin. However, NLRC4 in astrocytes also mediate inflammasome activation in response to lysophosphatidylcholine (LPC), an inflammatory molecule associated with neurologic disorders. In addition to NLRC4, astrocytic NLRP3 is required for inflammasome activation by LPC. Two biochemical assays show the interaction of NLRC4 with NLRP3, suggesting the possibility of a NLRC4-NLRP3 co-inflammasome. iii To study the physiologic relevance of NLRC4 in the brain, Nlrc4 -/- mice showed a pronounced delay in astrogliosis, a partial reduction in microglial accumulation, mature oligodendrocyte numbers and demyelination during neuroinflammation and demyelination. These results revealed an in vivo role for NLRC4 in a neurologic disease model that is not due to a bacterial infection. iv I dedicate this work to my loving sister Joy M. Bobb-Semple who showed me the embodiment of love, self sacrifice, generosity, perseverance, courage and determination. During my most difficult times I always remember Joy’s strength, fight, humor and determination as well as her honesty during her own personal struggles and battles. And so I pray I can have one tenth of the will, strength and determination that she showed, as she remains a beacon of hope during my most difficult and trying times and my guardian angel who has looked out for me since I was little child and still looks out for me as an adult today. v ACKNOWLEDGEMENTS First I would like to thank my mentor Dr. Jenny Ting for her patience, compassion, understanding and never ending support in helping me to develop as a graduate student. She has provided me a tremendous and rare once in life time opportunity to work in her laboratory. Working in Dr. Jenny Ting’s lab over the years has exposed me to a multitude of collaborative scientific opportunities, endeavors and to be apart of a lab environment that constantly evolves and that is at the cutting edge of broad novel scientific ideas and areas of application. I am not certain what my scientific future will hold but I am certain that I will probably not have the opportunity to work in a laboratory like that of Dr. Jenny Ting’s, and for that I will be eternally grateful to her for granting me the opportunity and privilege to work in her lab. I would to thank my committee members: Dr. Glenn Matsushima, Dr. Beverly H. Koller, Dr. Silva S. Markovic-Plese, Dr. Jenny Ting, and Dr. Pauline Kay Lund for taking the time out of their busy schedules to help me develop as graduate student and challenge me to think critically about scientific experiments and concepts. They have been invaluable resources in terms of sharing ideas and new techniques vi I would like to thank Dr. Antonio Baines, Dr. Ashalla Freeman, and Dr. Patricia Phelps of the IMSD program for their help as an external resource in providing me with guidance and future opportunities as a developing graduate student. I would also like to thank my friends Nick Gomez, Tikki Hayes, Daniel Dominguez and Kyle Gualton for their friendship, solace, support and insight during my time as a graduate student. I would also like to thank former and present colleagues such as Haitao Guo, Justin Wilson, Justin Callaway, Coy Allen, Monika Schneider, Beckley Davis, Greg Robbins, Adeeb Rahman, Brianne Barker and Erin McElvania TeKippe for taking the time out of their busy work schedules to provide insight and assistance in the progression and development of my projects. vii TABLE OF CONTENTS LIST OF TABLES ............................................................................................................ xii LIST OF FIGURES ......................................................................................................... xiii LIST OF ABBREVIATIONS .......................................................................................... xvi CHAPTER 1: The pathogenic role of the inflammasome in neurodegenerative diseases ..1 1.1 Introduction to Inflammasomes and Neuroinflammation ..................................1 1.2 The Inflammasome and Alzheimer’s disease and Disease Models ...................5 1.3 The Inflammasome and Traumatic Brain Injury .............................................11 1.4 The Inflammasome and Cerebral Ischemic Stroke ..........................................15 1.5 The Inflammasome and Multiple Sclerosis .....................................................19 1.6 The Inflammasome and Parkinson’s disease ...................................................23 1.7 Conclusions ......................................................................................................30 1.8 Introduction to PKC subfamilies .....................................................................35 1.9 The role of PKC-δ during cardiovascular disease ...........................................39 1.10 The role of PKC-δ during cancer ...................................................................40 1.11 The role of PKC-δ in immunology ............................................................... 43 viii CHAPTER 2: A role for the NLR family members NLRC4 and NLRP3 in astrocytic inflammasome activation and astrogliosis .......................................47 2.1. Overview .........................................................................................................47 2.2. Introduction .....................................................................................................49 2.3 Results ..............................................................................................................55 2.3.1 Nlrc4 expression in the cuprizone model of demyelination .........................55 2.3.2 Nlrc4 expression in multiple sclerosis and normal human brain ................. 57 2.3.3 Astrocytic NLRC4 displays the same specificity for flagellin as macrophage NLRC4 ...........................................................................60 2.3.4 NLRC4 and NLRP3 mediate lysophosphatidylcholine induced IL-1β release from mouse primary macrophages .....................................64 2.3.5 LPC-mediated release of IL-1β in astrocytes is Nlrc4 and Nlrp3 dependent ..............................................................................................67 2.3.6 NLRC4 and NLRP3 associate in a biochemical assay .................................69 ix 2.3.7 Astrogliosis is delayed in Nlrc4 -/- mice .........................................................72 2.3.8 Accumulation of microglia/macrophages is delayed in Nlrc4 -/- mice ..........74 2.3.9 Demyelination is delayed in cuprizone-treated Nlrc4 -/- mice .......................76 2.4 Discussion .......................................................................................................78 2.5 Materials and Methods .....................................................................................82 2.6 Supplemental Figures...................................................................................... 90 CHAPTER 3: A potential role for PKC-δ during Neuroinflammation .............................92 3.1 Introduction ......................................................................................................92 3.2 Results ..............................................................................................................94 3.2.1 PKC-δ selective inhibitors inhibit LPC mediated IL-1β release in WT BMMs ...................................................................................94 3.2.2 LPC stimulation of WT BMMs results in phosphorylation of PKC-δ .................................................................................96 3.2.3 LPC measurement of cuprizone treated brains in WT and Nlrc4 -/- mice ..............................................................................98 3.2.4 PKC-δ gene expression in mouse tissues ....................................................100 3.2.5. PKC-δ protein expression decreases in cuprizone treated brains with increasing cuprizone exposure ........................102 3.3 Discussion .....................................................................................................104 3.4 Materials and Methods ..................................................................................107