Nonobese diabetic (NOD) mice are a widely used animal model to study mechanisms leading to autoimmune diabetes. A gluten-free diet reduces and delays the incidence of diabetes in NOD mice, but the underlying mechanisms remain largely unknown. In this study, we performed single-cell transcriptomic and flow cytometry analysis of T cells and innate lymphocytes in the spleen and pancreatic lymph nodes of NOD mice fed a gluten-free or standard diet. We observed that the gluten-free diet did not induce a substantial alteration in the abundance or phenotype of any lymphocyte subset that would directly explain its protective effect against diabetes. However, the gluten-free diet induced subtle changes in the differentiation of subsets with previously proposed protective roles in diabetes development, such as Tregs, activated γδT cells, and NKT cells. Globally, the gluten-free diet paradoxically promoted activation and effector differentiation across multiple subpopulations and induced genes regulated by IL-2, IL-7, and IL-15. In contrast, the standard diet induced type I interferon-responsive genes. Overall, the gluten-free diet might prevent diabetes in NOD mice by inducing small-scale changes in multiple cell types rather than acting on a specific lymphocyte subset.

• Keywords
• NOD mice, T regulatory cells, gluten‐free diet, single‐cell transcriptomics, type I diabetes,
• MeSH
• Lymphocyte Activation immunology   MeSH
• Diet, Gluten-Free * MeSH
• Cell Differentiation MeSH
• Diabetes Mellitus, Type 1 * immunology   MeSH
• Mice, Inbred NOD MeSH
• Mice MeSH
• T-Lymphocyte Subsets * immunology   MeSH
• Transcriptome MeSH
• Animals MeSH
• Check Tag
• Mice MeSH
• Female MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH

Studies have documented that the pathogenesis of autoimmune diabetes is influenced by the intake of gluten. Aims. To investigate the importance of gluten exposure during pregnancy and the subsequent development of autoimmune diabetes in offspring. Methods. Nonobese diabetic mice were divided into 7 groups to receive combinations of gluten-free and standard diet before, during, or after pregnancy. Diabetes incidence in offspring was followed in each group (n = 16-27) for 310 days. Insulitis score and intestinal expression of T-cell transcription factors (RT-QPCR) were evaluated in animals from the different diet groups. Results. If mothers were fed a gluten-free diet only during pregnancy, the development of autoimmune diabetes in offspring was almost completely prevented with an incidence reduction from 62.5% in gluten-consuming mice to 8.3% (p < 0.0001) in the gluten-free group. The islets of Langerhans were less infiltrated (p < 0.001) and the intestinal expression of RORγt (Th17) (p < 0.0001) reduced in mice whose mothers were Gluten-free during pregnancy. Conclusion. A gluten-free diet exclusively during pregnancy efficiently prevents autoimmune diabetes development in offspring and reduces insulitis and intestinal expression of RORγt (Th17).

• MeSH
• Diet, Gluten-Free methods   MeSH
• Diabetes Mellitus, Type 1 diet therapy   immunology   prevention & control   MeSH
• Nuclear Receptor Subfamily 1, Group F, Member 3 genetics   MeSH
• Islets of Langerhans immunology   pathology   MeSH
• RNA, Messenger metabolism   MeSH
• Mice, Inbred NOD MeSH
• Mice MeSH
• Pancreatitis immunology   pathology   MeSH
• Reverse Transcriptase Polymerase Chain Reaction MeSH
• Intestinal Mucosa metabolism   MeSH
• Pregnancy in Diabetics diet therapy   MeSH
• Pregnancy MeSH
• TCF Transcription Factors genetics   MeSH
• Animals MeSH
• Check Tag
• Mice MeSH
• Pregnancy MeSH
• Female MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH
• Names of Substances
• Nuclear Receptor Subfamily 1, Group F, Member 3 MeSH
• RNA, Messenger MeSH
• TCF Transcription Factors MeSH

Induction of long-term tolerance to β-cell autoantigens has been investigated both in animal models and in human type 1 diabetes (T1D) in order to prevent the disease. As regards external compounds, the dietary plant protein fraction has been associated with high penetrance of the disease, whereas gluten-free diets prevent T1D in animal models. Herewith we investigated whether intranasal (i.n.) administration of gliadin or gluten may arrest the diabetogenic process. I.n. administration of gliadin to 4-week-old NOD mice significantly reduced the diabetes incidence. Similarly, the insulitis was lowered. Intranasal gliadin also rescued a fraction of prediabetic 13-week-old NOD mice from progressing to clinical onset of diabetes compared to OVA-treated controls. Vaccination with i.n. gliadin led to an induction of CD4(+)Foxp3(+) T cells and even more significant induction of γδ T cells in mucosal, but not in non-mucosal lymphoid compartments. This prevention strategy was characterized by an increased proportion of IL-10 and a decreased proportion of IL-2, IL-4 and IFN-γ-positive CD4(+)Foxp3(+) T cells, and IFN-γ-positive γδ T cells, preferentially in mucosal lymphoid organs. In conclusion, i.n. vaccination with gliadin, an environmental antigen with possible etiological influence in T1D, may represent a novel, safer strategy for prevention or even early cure of T1D.

• MeSH
• Administration, Intranasal MeSH
• CD4-Positive T-Lymphocytes immunology   MeSH
• Cytokines metabolism   MeSH
• Diabetes Mellitus, Type 1 drug therapy   immunology   prevention & control   MeSH
• Forkhead Transcription Factors metabolism   MeSH
• Gliadin administration & dosage   therapeutic use   MeSH
• Glutens administration & dosage   MeSH
• Humans MeSH
• Lymphoid Tissue immunology   pathology   MeSH
• Mice, Inbred NOD MeSH
• Lymphocyte Count MeSH
• Immunity, Mucosal MeSH
• Animals MeSH
• Check Tag
• Humans MeSH
• Female MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Names of Substances
• Cytokines MeSH
• Forkhead Transcription Factors MeSH
• FOXP3 protein, human MeSH Browser
• Gliadin MeSH
• Glutens MeSH

Metagenomic approaches are currently being used to decipher the genome of the microbiota (microbiome), and, in parallel, functional studies are being performed to analyze the effects of the microbiota on the host. Gnotobiological methods are an indispensable tool for studying the consequences of bacterial colonization. Animals used as models of human diseases can be maintained in sterile conditions (isolators used for germ-free rearing) and specifically colonized with defined microbes (including non-cultivable commensal bacteria). The effects of the germ-free state or the effects of colonization on disease initiation and maintenance can be observed in these models. Using this approach we demonstrated direct involvement of components of the microbiota in chronic intestinal inflammation and development of colonic neoplasia (i.e., using models of human inflammatory bowel disease and colorectal carcinoma). In contrast, a protective effect of microbiota colonization was demonstrated for the development of autoimmune diabetes in non-obese diabetic (NOD) mice. Interestingly, the development of atherosclerosis in germ-free apolipoprotein E (ApoE)-deficient mice fed by a standard low-cholesterol diet is accelerated compared with conventionally reared animals. Mucosal induction of tolerance to allergen Bet v1 was not influenced by the presence or absence of microbiota. Identification of components of the microbiota and elucidation of the molecular mechanisms of their action in inducing pathological changes or exerting beneficial, disease-protective activities could aid in our ability to influence the composition of the microbiota and to find bacterial strains and components (e.g., probiotics and prebiotics) whose administration may aid in disease prevention and treatment.

• MeSH
• Autoimmune Diseases etiology   microbiology   MeSH
• Gastrointestinal Tract microbiology   MeSH
• Germ-Free Life * MeSH
• Immunity MeSH
• Humans MeSH
• Metagenome immunology   MeSH
• Disease Models, Animal MeSH
• Neoplasms etiology   microbiology   MeSH
• Mucous Membrane immunology   MeSH
• Inflammation etiology   microbiology   MeSH
• Animals MeSH
• Check Tag
• Humans MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Review MeSH