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RESEARCH PRODUCT

A266 AMYLASE TRYPSIN INHIBITORS FROM WHEAT EXACERBATE GLUTEN-INDUCED PATHOLOGY AND ALTER GUT MICROBIOTA IN MICE

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BACKGROUND: Celiac disease (CeD) is an autoimmune enteropathy triggered by gluten in genetically susceptible individuals expressing HLA DQ2 or DQ8. The adaptive immune response is characterized by a gluten-specific T-cells, anti-gluten and anti-tissue transglutaminase-2 antibodies. Proliferation and activation of intraepithelial lymphocytes (IELs) is central to the innate immune response, although the triggers and receptors remain unclear. Amylase trypsin inhibitors (ATIs) are pest-resistant molecules in modern wheat with TLR4-activating capacities in mononuclear phagocytic cells. AIMS: Our aim was to determine whether ATIs act as innate activators, enhancing gluten immunopathology in mice. METHODS: NOD/DQ8 mice sensitized with cholera toxin and gliadin received a diet containing: 1) ATIs with no gluten (ATIs), 2) gluten de-enriched of ATIs (G-deATIs), or 3) G supplemented with ATIs (G+ATIs), for 2 weeks. Non-sensitized NOD/DQ8 (controls) received a wheat-free diet (WFD) for 2 weeks. To determine if ATIs could induce symptoms of wheat-sensitivity in non-genetically susceptible mice, C57BL/6 were placed on WFD or ATI diet for 1 week. CD3(+) IELs were measured by immunohistochemistry, paracellular permeability by Ussing chambers and 16s profiles of cecal contents via Illumia MiSeq. RESULTS: NOD/DQ8 mice receiving G+ATIs developed increased paracellular permeability, higher CD3(+) IEL counts and decreased villous-to-crypt (V/C) ratios compared with controls fed a WFD. Mice receiving ATIs and G+ATIs had lower Lactobacillus abundance in comparison with mice on a WFD and G-deATIs, respectively. An in vitro screen of ATI metabolism by bacteria, suggested that commensals are capable of degrading ATIs, including some Lactobacillus strains. C57BL/6 mice on an ATI diet developed increased paracellular permeability and CD3(+) IELs in comparison to mice on a WFD, but no decreases in V/C ratios. CONCLUSIONS: Our results indicate that ATIs induce IELs and exacerbate gluten-induced pathology in susceptible mice, while only leading to innate immune activation in WT mice. Thus, ATIs in wheat may initiate innate immunity in celiac disease or promote symptom generation in people with Non-Celiac Wheat Sensitivity. Supplementation with Lactobacillus strains involved in ATI metabolism may help attenuate gluten-related disorders. FUNDING AGENCIES: CIHR