Airway Mucin Dynamics in Infection and Inflammation
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AIRWAY MUCIN DYNAMICS IN INFECTION AND INFLAMMATION Bethany Batson A dissertation submitted to the faculty at the University of North Carolina at Chapel Hill in partial fulfillment of the requirements for the degree of Doctor in Philosophy in the Department of Pathology and Laboratory Medicine in the School of Medicine. Chapel Hill 2019 Approved by: Claire Doerschuk Mehmet Kesimer Jonathon Homeister Marianne Muhlebach Wanda O’Neal © 2019 Bethany Batson ALL RIGHTS RESERVED ii ABSTRACT Bethany Batson: Airway Mucin Dynamics in Infection and Inflammation (Under the direction of Mehmet Kesimer) Mucus plays a critical role in the innate immunity of the airways acting as the body’s first line of defense against pathogens. Mucus is a complex gel and much is still unknown regarding its constituents and how these cooperatively imbue mucus with its physiological and rheological properties. One such component, mucin, a large polymeric glycoprotein, is responsible for many of the rheological properties of mucus and its concentration has been linked to the development of several airway diseases. The importance of a properly functioning and mobile mucus layer is most evident when it becomes defective, a defining feature of the cystic fibrosis (CF) and asthmatic airway disease, which can have devastating consequences. A better understanding of why mucus becomes static and occludes airways or becomes a nidus for infection would not only clarify the pathogenesis of these diseases, but would inform future therapeutic advances. Using in vitro models and in vivo sputum samples, the following body of work aims to elucidate and characterize how the various mucus components including mucin, mucin interacting proteins, and regulatory exosomal miRNAs change in CF and asthmatic lung environments with the hypothesis that these qualitative and quantitative changes are key drivers in the development of pathologic mucus. We will show that the ratio of the two main gel- iii forming mucins is unique to specific airway diseases as are the proteins with which theses mucin interact. A specific focus will be placed on IgGFc-binding protein (FCGBP), a mucin interacting protein predicted to stabilize the colonic mucus layer, which we show is differentially secreted in CF and asthma lung environments. Several exosomal miRNA were identified that target mucin and its glycosylation machinery which also show disease specificity in regards to their expression. These findings broaden our understanding of how mucins are altered and contribute to the function of mucus in health and disease. iv ACKNOWLEDGMENTS Countless individuals have played a role in the creation, revision, and completion of this body of work. My committee members, Dr. Claire Doerschuk, Dr. Marianne Muhlebach, Dr. Wanda O’Neal, Dr. Jonathon Homeister, and Dr. Mehmet Kesimer provided the encouragement and input that facilitated the completion of my work and graduate studies. I would like to dedicate this work to my mentor, Mehmet Kesimer, who nurtured my enthusiasm for research and gave me the opportunity to become an independent investigator. This work would not have been possible without his blessing and guidance. Not only did you push me scientifically, but your continued support while I struggled with a difficult pregnancy and a newborn made finishing my PhD a reality. I have spent the past five years in the Kesimer lab, which have been filled with riveting scientific (and non-scientific) conversation, laughter, and collaboration, and exciting science. Each member of the lab has enhanced my graduate experience with their specific area of technical expertise but also in other less scientific ways. From Giorgia Radicioni, I have learned about Italy and scuba diving; from Boris Reidel, everything German and Star Wars; from Jerome Carpenter, anything sports, PowerPoint animations, and what it means to be “optihensive”, with Stephanie Livengood, I have shared my love for cats and dogs; and from Sabri Abdelwahab, I have learned about selfless generosity and developed v a heightened appreciation for Baklava. I could never forget, the former lab manager and one of my best friends, Amina Ford, who taught me how to laugh through difficult times and that regardless of your title and position, with hard work you can achieve great things. I not only view these individuals as my labmates, but my friends and North Carolina family. This work was truly a collaborative effort that involved numerous labs and core facilities within the CF center, and those both on and off UNCs’ campus. Within the Marsico Lung Institute and CF center I would like to acknowledge the following labs and cores: The CF Center Tissue Procurement and Cell Culture Core, The Molecular Biology Core, The Histology Core, The Michael Hooker Microscopy Core, and really the entire 7th floor of Marsico Hall. Outside of the CF center, I would like to recognize Dr. Brenda Temple from The UNC Center for Structural Biology, the High Throughput Genomic Sequencing Facility, Dr. Flavia Teles and Lynn Martin, and The UNC Animal Histopathology Core. Outside of UNC, I would like to acknowledge the fruitful collaboration with Dr. Tiemeyer and Tadahiro Kumagai from University of Georgia’s Complex Carbohydrate Research Center. Lastly I would like to thank my family. My husband, Kellen Batson, has provided unending encouragement, unconditional love and support, which started with his willingness to move from the West Coast to North Carolina and continues even now as he encourages me to pursue my dream of becoming a medical doctor. Life became a little bit more complicated when we decided to have Finley, but I wouldn’t choose to be married, parents, and best friends with anyone else! Finley Marie Batson, even though you are unaware of what I have been up to these last vi couple years, you have brought an incredible amount of joy, laughter, and smiles into my life. I work hard for you, my little cupcake, and hopefully one day you will be as proud of me as I already am of you. vii TABLE OF CONTENTS LIST OF FIGURES .................................................................................................. xiv LIST OF TABLES ..................................................................................................... xix LIST OF ABBREVIATIONS ..................................................................................... xxi INTRODUCTION: MUCUS & MUCIN ........................................................................ 1 CHAPTER 1. PART A: COMPREHENSIVE CHARACTERIZATION OF MUCINS WITHIN THE CF AIRWAY USING IN-VITRO MODELS ................. 7 Introduction: Cystic Fibrosis ................................................................................... 7 Methods ............................................................................................................... 11 Cell Culture ....................................................................................................... 11 CF cell culture models ...................................................................................... 11 Mucin Isolation and Static Light Scattering ....................................................... 12 Isolation and Analysis of Stored Gel Forming Mucins ....................................... 13 Whole Mount Immunohistochemistry (IHC) ...................................................... 13 Agarose Gel Electrophoresis ............................................................................ 14 Mass Spectrometry ........................................................................................... 15 Proteomic Semi-tryptic peptide analysis ........................................................... 17 Rate Zonal Centrifugation ................................................................................. 17 Exosome Isolation ............................................................................................ 18 MUC5B and MUC5AC Standard In-Vitro Experimental Design ........................ 18 Results: ................................................................................................................ 20 viii CF Cell Culture Models: Immunohistochemistry and MUC5B and MUC5AC concentration quantitation ......................................................... 20 SMM: MUC5AC and MUC5B concentration quantitation .................................. 21 CF cell culture models: Macromolecular characterization of secreted and intracellular gel forming mucins .......................................................... 21 Ps.a. cell culture model: MUC5B Semi-tryptic peptide analysis ........................ 23 CF cell culture models: Conformation analysis of the secreted gel forming mucins .......................................................................................... 24 SMM cell culture model: Proteomic pathway analysis of secreted proteins ...... 24 Ps.a. cell culture model: Proteomic pathway analysis of secreted proteins ...... 25 Proteomic comparison of secretions from SMM and Ps.a. CF cell culture models ........................................................................................... 26 CF Cell culture models: Proteomic analysis of mucin interacting proteins in secretions ................................................................................ 26 Ps.a. CF cell culture model: Pathway analysis of differentially expressed exosomal miRNA ...................................................................................... 27 Ps.a. CF cell culture model: In silico MUC5B activity prediction