A role for bacterial-derived proteases and protease inhibitors in food sensitivity.

TLDR: The gut microbiota as a therapeutic approach for gastrointestinal disorders and experimental evidence for the role of the gut microbiota in celiac disease pathogenesis are studied.

Abstract: ...................................................................................................................... iii ACKNOWLEDGMENTS ................................................................................................ vi TABLE OF CONTENTS ................................................................................................ vii LIST OF FIGURES ........................................................................................................ xii LIST OF TABLES .......................................................................................................... xvi LIST OF ABBREVIATIONS ....................................................................................... xvii CHAPTER 1: INTRODUCTON ...................................................................................... 1 1.1 The gastrointestinal immune system ......................................................................... 2 1.1.1 Innate mucosal immunity .................................................................................... 2 1.1.2 Adaptive mucosal immunity ................................................................................ 8 1.1.3 Tolerance to luminal antigens............................................................................ 11 1.2 The intestinal microbiota .......................................................................................... 15 1.2.1 The landscape of the intestinal microbiota ........................................................ 15 1.2.2 Dysbiosis and gastrointestinal disorders ........................................................... 17 1.2.3 Interactions between the mucosal immune system and intestinal microbiota .. 21 Justin L. McCarville – Ph.D. Thesis McMaster University – Medical Science viii 1.2.4 Targeting the intestinal microbiota as a therapeutic approach for gastrointestinal disorders ............................................................................................ 23 1.3 Celiac disease ............................................................................................................. 24 1.3.1 The adaptive immune response in celiac disease .......................................... 25 1.3.2 The innate immune response in celiac disease.............................................. 29 1.3.3 Modulation of celiac disease development and severity ............................... 33 1.4 Treatment of celiac disease........................................................................................ 33 1.5 The gut microbiota in celiac disease ......................................................................... 34 1.5.1 Clinical associations of the gut microbiota and celiac disease .................... 34 1.5.2 Experimental evidence for the role of the gut microbiota in celiac disease pathogenesis. .......................................................................................................... 37 1.5.3 Digestion of gluten by gastrointestinal bacteria ........................................... 40 1.6 Proteases and protease inhibitors in the gastrointestinal tract ............................ 41 1.6.1 Proteolytic balance in the gastrointestinal tract ........................................... 41 1.6.2 Recognition of proteases by protease activated receptors (PARs) ............... 43 1.6.3 Proteolytic imbalances in IBD and functional bowel disorders ................... 45 1.6.4 Proteolytic imbalance in celiac disease ........................................................ 48 1.6.5 Bacteria as a source of proteases and protease inhibitors ............................ 49 1.6.6 Bacteria as contributors of proteolytic imbalances in gastrointestinal disorders ................................................................................................................ 51 Justin L. McCarville – Ph.D. Thesis McMaster University – Medical Science ix CHAPTER 2: THESIS OBJECTIVES .......................................................................... 54 THESIS SCOPE ..................................................................................................... 55 THESIS AIMS ...................................................................................................... 56 CHAPTER 3: DUODENAL BACTERIAL FROM PATIENTS WITH CELIAC DISEASE AND HEALTHY SUBJECTS DISTINCTLY AFFECT GLUTEN BREAKDOWN AND IMMUNOGENICITY ................................................................ 59 SUMMARY .......................................................................................................... 60 ABSTRACT .......................................................................................................... 64......................................................................................................... 64 INTRODUCTION ................................................................................................ 66 METHODS ........................................................................................................... 67 RESULTS ............................................................................................................. 74 DISCUSSION ........................................................................................................ 92 ACKNOWLEDGMENTS .................................................................................... 97 REFERENCES ..................................................................................................... 98 SUPPLEMENTARY MATERIALS .................................................................. 105 CHAPTER 4: MICROBIAL PROTEASES MODULATE INNATE IMMUNITY AND INCREASE SENSITIVITY TO DIETARY ANITGEN THROUGH PAR-2 119 SUMMARY ........................................................................................................ 120 ABSTRACT ........................................................................................................ 124....................................................................................................... 124 Justin L. McCarville – Ph.D. Thesis McMaster University – Medical Science x INTRODUCTION .............................................................................................. 125 METHODS ......................................................................................................... 127 RESULTS ........................................................................................................... 133 DISCUSSION ...................................................................................................... 133 ACKNOWLEDGMENTS .................................................................................. 146 SUPPLEMENTARY FIGURES ......................................................................... 150 REFERENCES ................................................................................................... 156 CHAPTER 5: A COMMENSAL BIFIDOBACTERIUM LONGUM STRAIN IMPROVES GLUTEN-RELATED IMMUNOPATHOLOGY IN MICE THROUGH EXPRESSION OF A SERINE PROTEASE INHIBITOR ....................................... 161 SUMMARY ........................................................................................................ 162 ABSTRACT ........................................................................................................ 166....................................................................................................... 166 INTRODUCTION .............................................................................................. 167 METHODS ......................................................................................................... 169 RESULTS ........................................................................................................... 178 DISCUSSION ...................................................................................................... 190 ACKNOWLEDGMENTS .................................................................................. 195 REFERENCES ................................................................................................... 196 SUPPLEMENTARY FIGURES ......................................................................... 199 Justin L. McCarville – Ph.D. Thesis McMaster University – Medical Science xi DISCUSSION ................................................................................................................ 208 6.1 Summary ................................................................................................................... 209 6.2 Commensal-derived proteases metabolize gluten producing peptides with different immunogenicity .............................................................................................. 211 6.3 Commensal-derived proteases trigger intestinal inflammation and exacerbate pathology ......................................................................................................................... 214 6.4 Delivery of a protease inhibitor by a commensal bacterium prevents gluteninduced pathology ......................................................................................................... 218 6.5 Future Directions .................................................................................................... 220 6.6 Conclusions ............................................................................................................... 221 REFERENCES ............................................................................................................... 225 APPENDIX I: NOVEL PERSPECTIVES ON THE HERAPEAUTIC MODULATION OF THE GUT MICROBIOTA ...................................................... 240 APPENDIX II: PHARMACOLOGICAL APPRAOCHES IN CELIAC DISEASE .......................................................................................................................................... 255 APPENDIX III: INTESTINAL MICROBIOTA MODULATES GLUTENINDUCE