Enhancement of autoimmunity in type 1 diabetes by gluten

Ingested food affects the composition of intestinal microbes, whereas microbes can affect the development of autoimmunity, including Type 1 diabetes (T1D). Many experiments conducted in animals and observations made in humans were suggestive of the importance of diet. Those dietary interventions that changed the development of T1D attracted our attention because they can be applied to large and diverse groups of people. We are interested in understanding how strongly dietary interventions depend on the microbiota and how they influence the immune system and disease development. The results of our preliminary experiments revealed that Hydrolyzed Casein (HC)-based diet was a microbiota-independent protector, whereas addition of gluten to HC diet caused a microbiota-dependent loss of protection. We hypothesized that protection works be relieving beta cells from stress minimizing activation of autoimmunity. Gluten’s mode of action is facilitation of both adaptive and innate immune mechanisms. To further uncover the mechanisms behind exacerbating properties of gluten, we will pursue the following aims: Specific Aim 1. Investigate the immune mechanisms involved in dietary protection from T1D and its reversal by gluten. · Analyze gene and protein marker expression at the single cell level in islets and pancreatic lymph nodes (PLN) of mice on different diets using single cell sequencing and multiparameter flowcytometry. · Perform functional testing of antigen presentation in animals fed different diets. · Perform functional comparisons of effector and regulatory T cell in these animals. · Perform analysis of other cell types in the islets and PLN. Specific Aim 2. Understand the autoimmune consequences of gluten and microbiota interactions. · Analyze the role of bacterial proteolysis in generation of the TCR agonists - peptides recognized by mouse T cells in the context of H-2g7. · To test the hypothesis that bacterial digest of gluten produces cross-reactive agonists that can cross- stimulate anti-islet responses. · Address the role of biologically active proteolytic products of gluten in innate immune system activation in vitro and, more importantly, in vivo.