Effect of dietary gluten on dendritic cells and innate immune subsets in BALB/c and NOD mice

Expression of tolerogenic dendritic cells in the small intestinal tissue of patients with celiac disease

Tolerogenic dendritic cells (tolCDs) play an important role in the regulation of inflammation in autoimmune diseases such as celiac disease (CeD). Dendritic cells express CD207, CD11c, and CD103 on their surface. In addition to the receptors mentioned above, tolCDs can express the immune-regulating enzyme indoleamine 2,3-dioxygenase (IDO). This study aimed to determine the mRNA and protein expression of CD11c, CD103 and CD207 markers, and also IDO gene expression in intestinal tissues of CeD patients in comparison to the healthy individuals. Duodenal biopsies were collected from 60 CeD patients and 60 controls. Total RNA was extracted and gene expression analysis was performed using Real-time PCR SYBR® Green method. Additionally, biopsy specimens were paraffinized and protein expression was evaluated using immunohistochemistry (IHC) for expression of CD11c+, CD207+and CD103+. Gene expression levels of CD11c (P = 0.045), CD103 (P < 0.001), CD207 (P < 0.001) and IDO (P = 0.01) were significantly increased in CeD patients compared to the control group. However, only CD103 protein expression was found to be significantly higher in CeD patients in comparison to the control group (P < 0.001). The result of this study showed that the expresion levels of CD11c, CD103, CD207 and IDO markers were higher in CeD patients compared to the controls, indicating the effort of dendritic cells to counterbalance the gliadin-triggered abnormal immune responses in CeD patients.

Prevalence of haplotype DQ2/DQ8 and celiac disease in children with type 1 diabetes

Type 1 diabetes (T1D) and celiac disease (CD) coexist very often. Identification of the human leukocyte antigen (HLA) DQ2/DQ8 can confirm the genetic predisposition to CD. Negative result of this test allows to exclude CD with a high probability. It was suggested that in individuals with higher risk of CD, including T1D patients, the implementation of genetic testing should reduce the number of patients requiring systematic immunological screening. The aim of this study was to analyze the prevalence of different haplotypes predisposing to CD in children and adolescents with previously diagnosed T1D.

MATERIAL AND METHODS

A retrospective analysis was performed on 166 T1D children (91 girls) in whom HLA DQ2/DQ8 alleles were tested. In 9.6% CD was also diagnosed.

RESULTS

In 12.7% both HLA DQ2/DQ8 were negative. In 87.3% patients HLA DQ2 and/or DQ8 was positive, including 27.7% patients with both haplotypes DQ2.5 and DQ8 positive. In all CD patients the disease predisposing alleles were positive, while none of the HLA DQ2/DQ8 negative children were diagnosed with CD.

CONCLUSIONS

The prevalence of HLA DQ2.5 and the HLA DQ2.5 / HLA DQ8 configuration is higher in patients with T1D, and CD compared to children with T1D alone. The combination of HLA DQ2 and HLA DQ8 most significantly increases the risk of developing CD. The group of HLA DQ2/DQ8 negative patients with improbable CD diagnosis, is relatively small. Most of T1D patients HLA DQ2/DQ8 positive need further regular antibody assessment. In patients with T1D, who are at high risk of developing CD, genetic testing may be considered to select those who require further systematic serological evaluation. Due to its retrospective nature, the study was not registered in the database of clinical trials and the Clinical trial registration number is not available.

The etiology and pathogenesis of type 1 diabetes - A personal, non-systematic review of possible causes, and interventions

In this review after a lifelong research career, my personal opinion on the development of type 1 diabetes (T1D) from its very start to clinical manifestation will be described. T1D is a disease of an increased intestinal permeability and a reduced pancreas volume. I am convinced that virus might be the initiator and that this virus could persist on strategically significant locations. Furthermore, intake of gluten is important both in foetal life and at later ages. Disturbances in sphingolipid metabolism may also be of crucial importance. During certain stages of T1D, T cells take over resulting in the ultimate destruction of beta cells, which manifests T1D as an autoimmune disease. Several preventive and early treatment strategies are mentioned. All together this review has more new theories than usually, and it might also be more speculative than ordinarily. But without new ideas and theories advancement is difficult, even though everything might not hold true during the continuous discovery of the etiology and pathogenesis of T1D.

Gut-Ex-Vivo system as a model to study gluten response in celiac disease

Celiac disease (CD) is a complex immune-mediated chronic disease characterized by a consistent inflammation of the gastrointestinal tract induced by gluten intake in genetically predisposed individuals. Although initiated by the interaction between digestion-derived gliadin, a gluten component, peptides, and the intestinal epithelium, the disorder is highly complex and involving other components of the intestine, such as the immune system. Therefore, conventional model systems, mainly based on two- or three-dimension cell cultures and co-cultures, cannot fully recapitulate such a complex disease. The development of mouse models has facilitated the study of different interacting cell types involved in the disorder, together with the impact of environmental factors. However, such in vivo models are often expensive and time consuming. Here we propose an organ ex vivo culture (gut-ex-vivo system) based on small intestines from gluten-sensitive mice cultivated in a dynamic condition, able to fully recapitulate the biochemical and morphological features of the mouse model exposed to gliadin (4 weeks), in 16 h. Indeed, upon gliadin exposure, we observed: i) a down-regulation of cystic fibrosis transmembrane regulator (CFTR) and an up-regulation of transglutaminase 2 (TG2) at both mRNA and protein levels; ii) increased intestinal permeability associated with deregulated tight junction protein expression; iii) induction and production of pro-inflammatory cytokines such as interleukin (IL)-15, IL-17 and interferon gamma (IFNγ); and iv) consistent alteration of intestinal epithelium/villi morphology. Altogether, these data indicate that the proposed model can be efficiently used to study the pathogenesis of CD, test new or repurposed molecules to accelerate the search for new treatments, and to study the impact of the microbiome and derived metabolites, in a time- and cost- effective manner.

Why is the Incidence of Type 1 Diabetes Increasing?

Type 1 diabetes is a condition that can lead to serious long-term complications and can have significant psychological and quality of life implications. Its incidence is increasing in all parts of the world, but the reasons for this are incompletely understood. Genetic factors alone cannot explain such a rapid increase in incidence; therefore, environmental factors must be implicated. Lifestyle factors have been classically associated with type 2 diabetes. However, there are data implicating obesity and insulin resistance to type 1 diabetes as well (accelerator hypothesis). Cholesterol has also been shown to be correlated with the incidence of type 1 diabetes; this may be mediated by immunomodulatory effects of cholesterol. There is considerable interest in early life factors, including maternal diet, mode of delivery, infant feeding, childhood diet, microbial exposure (hygiene hypothesis), and use of anti-microbials in early childhood. Distance from the sea has recently been shown to be negatively correlated with the incidence of type 1 diabetes. This may contribute to the increasing incidence of type 1 diabetes since people are increasingly living closer to the sea. Postulated mediating mechanisms include hours of sunshine (and possibly vitamin D levels), mean temperature, dietary habits, and pollution. Ozone, polychlorinated biphenyls, phthalates, trichloroethylene, dioxin, heavy metals, bisphenol, nitrates/nitrites, and mercury are amongst the chemicals which may increase the risk of type 1 diabetes. Another area of research concerns the role of the skin and gut microbiome. The microbiome is affected by many of the factors mentioned above, including the mode of delivery, infant feeding, exposure to microbes, antibiotic use, and dietary habits. Research on the reasons why the incidence of type 1 diabetes is increasing not only sheds light on its pathogenesis but also offers insights into ways we can prevent type 1 diabetes.

Genistein antagonizes gliadin-induced CFTR malfunction in models of celiac disease

In celiac disease (CD), an intolerance to dietary gluten/gliadin, antigenic gliadin peptides trigger an HLA-DQ2/DQ8-restricted adaptive Th1 immune response. Epithelial stress, induced by other non-antigenic gliadin peptides, is required for gliadin to become fully immunogenic. We found that cystic-fibrosis-transmembrane-conductance-regulator (CFTR) acts as membrane receptor for gliadin-derived peptide P31-43, as it binds to CFTR and impairs its channel function. P31-43-induced CFTR malfunction generates epithelial stress and intestinal inflammation. Maintaining CFTR in an active open conformation by the CFTR potentiators VX-770 (Ivacaftor) or Vrx-532, prevents P31-43 binding to CFTR and controls gliadin-induced manifestations. Here, we evaluated the possibility that the over-the-counter nutraceutical genistein, known to potentiate CFTR function, would allow to control gliadin-induced alterations. We demonstrated that pre-treatment with genistein prevented P31-43-induced CFTR malfunction and an epithelial stress response in Caco-2 cells. These effects were abrogated when the CFTR gene was knocked out by CRISP/Cas9 technology, indicating that genistein protects intestinal epithelial cells by potentiating CFTR function. Notably, genistein protected gliadin-sensitive mice from intestinal CFTR malfunction and gliadin-induced inflammation as it prevented gliadin-induced IFN-γ production by celiac peripheral-blood-mononuclear-cells (PBMC) cultured ex-vivo in the presence of P31-43-challenged Caco-2 cells. Our results indicate that natural compounds capable to increase CFTR channel gating might be used for the treatment of CD.

Diabetogenic effect of gluten in Wistar albino rats: a preliminary preclinical screening

Background and aims

Gluten-related disease affects less than 1% population and is not considered of relevance at the public health level. However, the consumption of a gluten-free diet has been most commonly adopted as a special diet worldwide in the recent past. In the present study, we investigated the association of gluten intake and diabetes in Wistar albino rats.

Methods

Thirty adult Wistar rats were randomly divided into five groups: control, diabetic, and test treated with pure gluten (100, 200 and 400 mg/kg body weight). Diabetes was induced in rats by intraperitoneal injection of Streptozotocin (65 mg/kg) after a dose of nicotinamide (110 mg/kg). Body weight, fasting blood glucose levels, postprandial blood glucose levels and histopathology of the pancreas were compared.

Results

Fasting blood glucose levels and postprandial blood glucose were significantly higher in diabetes animals but there were no significant changes in gluten treated groups. Other parameters were not significantly changed among different groups.

Conclusions

Gluten at doses 100 mg/kg, 200 mg/kg and 400 mg/kg is not a diabetogenic diet and hence it needs not be excluded from diet for the prevention and management of Type 2 diabetes mellitus.

Deamidation and Enzymatic Hydrolysis of Gliadins Alter Their Processing by Dendritic Cells in Vitro

Gliadins are major wheat allergens. Their treatment by acid or enzymatic hydrolysis has been shown to modify their allergenic potential. As the interaction of food proteins with dendritic cells (DCs) is a key event in allergic sensitization, we wished to investigate whether deamidation and enzymatic hydrolysis influence gliadin processing by DC and to examine the capacity of gliadins to activate DCs. We compared the uptake and degradation of native and modified gliadins by DCs using mouse bone marrow-derived DCs. We also analyzed the effects of these interactions on the phenotypes of DCs and T helper (Th) lymphocytes. Modifying gliadins induced a change in physicochemical properties (molecular weight, hydrophobicity, and sequence) and also in the peptide size. These alterations in turn led to increased uptake and intracellular degradation of the proteins by DCs. Native gliadins (NGs) (100 μg/mL), but not modified gliadins, increased the frequency of DC expressing CD80 (15.41 ± 2.36% vs 6.81 ± 1.10%, p < 0.001), CCR7 (28.53 ± 8.17% vs 17.88 ± 2.53%, p < 0.001), CXCR4 (70.14 ± 4.63% vs 42.82 ± 1.96%, p < 0.001), and CCR7-dependent migration (2.46 ± 1.45 vs 1.00 ± 0.22, p < 0.01) compared with NGs. This was accompanied by Th lymphocyte activation (30.37 ± 3.87% vs 21.53 ± 3.14%, p < 0.1) and proliferation (16.39 ± 3.97% vs 9.31 ± 2.80%, p > 0.1). Moreover, hydrolysis decreases the peptide size and induces an increase in gliadin uptake and degradation. Deamidation and extensive enzymatic hydrolysis of gliadins modify their interaction with DCs, leading to alteration of their immunostimulatory capacity. These findings demonstrate the strong relationship between the biochemical characteristics of proteins and immune cell interactions.

Parental Dietary Protein Source and the Role of CMKLR1 in Determining the Severity of Dahl Salt-Sensitive Hypertension

Studies from our laboratory have revealed an important role for the maternal diet and the dietary protein source in the development of hypertension and renal injury in Dahl salt-sensitive (SS) rats. The current study sought to compare salt-induced hypertension, renal damage, and immune cell infiltration in the offspring of breeders fed either a casein- or gluten-based diet, with the hypothesis that offspring from gluten-fed breeders would fail to develop these SS phenotypes. When fed identical diets post-weaning, the F1 generation gluten offspring demonstrated lower mean arterial pressure (149.1±3.1 versus 162.5±5.8 mm Hg), albuminuria (166.2±34.6 versus 250.9±27.8 mg/day), and outer medullary protein casting (7.4±0.8% versus 13.1±1.3%) in response to high salt compared with the casein offspring (n=9-11). The gluten offspring also had fewer CD45+ leukocytes, CD11b/c+ monocytes/macrophages, CD3+ T cells, and CD45R+ B cells infiltrating the kidney. Analysis of the F2 generation gluten offspring also exhibited lower mean arterial pressure and renal damage compared with rats born from casein breeders (n=7-9), with no difference in renal immune cell infiltration. CMKLR1-receptor for the novel prohypertensive adipokine chemerin-was found via polymerase chain reaction array to be significantly upregulated (2.99-fold) in renal T cells isolated from F2 offspring of casein-fed versus gluten-fed parents. Furthermore, CMKLR1 inhibition via α-NETA (2-[α-naphthoyl] ethyltrimethylammonium iodide) treatment significantly attenuated renal immune cell infiltration, hypertension, and renal damage in SS rats fed high salt. Together, these data demonstrate the influence of the parental diet in determining the salt-induced hypertension, renal damage, and inflammatory phenotype of the offspring.

Cystic fibrosis transmembrane conductance regulator (CFTR) and autophagy: hereditary defects in cystic fibrosis versus gluten-mediated inhibition in celiac disease

Cystic Fibrosis (CF) is the most frequent lethal monogenetic disease affecting humans. CF is characterized by mutations in cystic fibrosis transmembrane conductance regulator (CFTR), a chloride channel whose malfunction triggers the activation of transglutaminase-2 (TGM2), as well as the inactivation of the Beclin-1 (BECN1) complex resulting in disabled autophagy. CFTR inhibition, TGM2 activation and BECN1 sequestration engage in an ‘infernal trio’ that locks the cell in a pro-inflammatory state through anti-homeostatic feedforward loops. Thus, stimulation of CFTR function, TGM2 inhibition and autophagy stimulation can be used to treat CF patients. Several studies indicate that patients with CF have a higher incidence of celiac disease (CD) and that mice bearing genetically determined CFTR defects are particularly sensitive to the enteropathogenic effects of the orally supplied gliadin (a gluten-derived protein). A gluten/gliadin-derived peptide (P31–43) inhibits CFTR in mouse intestinal epithelial cells, causing a local stress response that contributes to the immunopathology of CD. In particular, P31–43-induced CFTR inhibition elicits an epithelial stress response perturbing proteostasis. This event triggers TGM2 activation, BECN1 sequestration and results in molecular crosslinking of CFTR and P31-43 by TGM2. Importantly, stimulation of CFTR function with a pharmacological potentiator (Ivacaftor), which is approved for the treatment of CF, could attenuate the autophagy-inhibition and pro-inflammatory effects of gliadin in preclinical models of CD. Thus, CD shares with CF a common molecular mechanism involving CFTR inhibition that might respond to drugs that intercept the "infernal trio". Here, we highlight how drugs available for CF treatment could be repurposed for the therapy of CD.

Role of Dietary Gluten in Development of Celiac Disease and Type I Diabetes: Management Beyond Gluten-Free Diet

Gluten triggers Celiac Disease (CD) and type I diabetes in genetically predisposed population of human leukocyte antigen DQ2/DQ8+ and associates with disorders such as schizophrenia and autism. Application of a strict gluten-free diet is the only well-established treatment for patients with CD, whereas the treatment for patients with celiac type I diabetes may be depend on the timing and frequency of the diet. The application of a gluten-free diet in patients with CD may contribute to the development of metabolic syndrome and nonalcoholic fatty liver disease and may also lead to a high glycemic index, low fiber diet and micronutrient deficiencies. The alteration of copper bioavailability (deficient, excess or aberrant coordination) may contribute to the onset and progress of related pathologies. Therefore, nutrient intake of patients on a gluten-free diet should be the focus of future researches. Other gluten-based therapies have been rising with interest such as enzymatic pretreatment of gluten, oral enzyme supplements to digest dietary gluten, gluten removal by breeding wheat varieties with reduced or deleted gluten toxicity, the development of polymeric binders to suppress gluten induced pathology.

A pathogenic role for cystic fibrosis transmembrane conductance regulator in celiac disease

Intestinal handling of dietary proteins usually prevents local inflammatory and immune responses and promotes oral tolerance. However, in ~ 1% of the world population, gluten proteins from wheat and related cereals trigger an HLA DQ2/8‐restricted T_H1 immune and antibody response leading to celiac disease. Prior epithelial stress and innate immune activation are essential for breaking oral tolerance to the gluten component gliadin. How gliadin subverts host intestinal mucosal defenses remains elusive. Here, we show that the α‐gliadin‐derived LGQQQPFPPQQPY peptide (P31–43) inhibits the function of cystic fibrosis transmembrane conductance regulator (CFTR), an anion channel pivotal for epithelial adaptation to cell‐autonomous or environmental stress. P31–43 binds to, and reduces ATPase activity of, the nucleotide‐binding domain‐1 (NBD1) of CFTR, thus impairing CFTR function. This generates epithelial stress, tissue transglutaminase and inflammasome activation, NF‐κB nuclear translocation and IL‐15 production, that all can be prevented by potentiators of CFTR channel gating. The CFTR potentiator VX‐770 attenuates gliadin‐induced inflammation and promotes a tolerogenic response in gluten‐sensitive mice and cells from celiac patients. Our results unveil a primordial role for CFTR as a central hub orchestrating gliadin activities and identify a novel therapeutic option for celiac disease.

Possible Prevention of Diabetes with a Gluten-Free Diet

Gluten seems a potentially important determinant in type 1 diabetes (T1D) and type 2 diabetes (T2D). Intake of gluten, a major component of wheat, rye, and barley, affects the microbiota and increases the intestinal permeability. Moreover, studies have demonstrated that gluten peptides, after crossing the intestinal barrier, lead to a more inflammatory milieu. Gluten peptides enter the pancreas where they affect the morphology and might induce beta-cell stress by enhancing glucose- and palmitate-stimulated insulin secretion. Interestingly, animal studies and a human study have demonstrated that a gluten-free (GF) diet during pregnancy reduces the risk of T1D. Evidence regarding the role of a GF diet in T2D is less clear. Some studies have linked intake of a GF diet to reduced obesity and T2D and suggested a role in reducing leptin- and insulin-resistance and increasing beta-cell volume. The current knowledge indicates that gluten, among many environmental factors, may be an aetiopathogenic factors for development of T1D and T2D. However, human intervention trials are needed to confirm this and the proposed mechanisms.

Influence of dietary protein on Dahl salt-sensitive hypertension: a potential role for gut microbiota

High blood pressure affects 1.39 billion adults across the globe and is the leading preventable cause of death worldwide. Hypertension is a multifaceted disease with known genetic and environmental factors contributing to its progression. Our studies utilizing the Dahl salt-sensitive (SS) rat have demonstrated the remarkable influence of dietary protein and maternal environment on the development of hypertension and renal damage in response to high salt. There is growing interest in the relationship between the microbiome and hypertension, with gut dysbiosis being correlated to a number of pathologies. This review summarizes the current literature regarding the interplay among dietary protein, the gut microbiota, and hypertension. These studies may provide insight into the effects we have observed between diet and hypertension in Dahl SS rats and, we hope, lead to new perspectives where potential dietary interventions or microbiota manipulations could serve as plausible therapies for hypertension.

Gluten-free diet during pregnancy alleviates signs of diabetes and celiac disease in NOD mouse offspring

BACKGROUND

Gluten-free (GF) diet during pregnancy ameliorates autoimmune diabetes in nonobese diabetic (NOD) mouse offspring. Due to comorbidity of celiac disease in type 1 diabetes, we hypothesized that GF diet in utero alleviates the humoral and histopathological signs of celiac disease in NOD mice. We aimed to establish the mechanisms behind the diabetes-protective effect of GF diet in utero.

METHODS

Breeding pairs of NOD mice were fed a GF or gluten-containing standard (STD) diet until parturition. The offspring were nursed by mothers on STD diet and continued on this diet until ages 4 and 13 weeks. Analyses of serum antitissue transglutaminase (anti-tTG) intestine and islet histology, islet transglutaminase (TG) activity, and cytokine expression in T cells from lymphoid organs were performed.

RESULTS

GF versus STD diet in utero led to reduced serum anti-tTG titre and increased villus-to-crypt ratio at both ages. Insulitis along with systemic and local inflammation were decreased, but islet TG activity was unchanged in 13-week-old GF mice. These mice had unchanged beta-cell volumes, but increased islet numbers throughout the prediabetic period.

CONCLUSIONS

Collectively, GF diet administered during pregnancy improves signs of celiac disease and autoimmune diabetes in the offspring. The diabetes-ameliorative effect of GF diet in utero is followed by dampening of inflammation, unchanged beta-cell volume, but increased islet numbers.

Obesity alters immune and metabolic profiles: New insight from obese-resistant mice on high-fat diet

OBJECTIVE

Diet-induced obesity has been shown to alter immune function in mice, but distinguishing the effects of obesity from changes in diet composition is complicated. It was hypothesized that immunological differences would exist between diet-induced obese (DIO) and obese-resistant (OB-Res) mice fed the same high-fat diet (HFD).

METHODS

BALB/c mice were fed either standard chow or HFD to generate lean or DIO and OB-Res mice, respectively. Resulting mice were analyzed for serum immunologic and metabolic profiles and cellular immune parameters.

RESULTS

BALB/c mice on HFD were categorized as DIO or OB-Res, based on body weight versus lean controls. DIO mice were physiologically distinct from OB-Res mice, whose serum insulin, leptin, gastric inhibitory polypeptide, and eotaxin concentrations remained similar to lean controls. DIO mice had increased macrophage(+) crown-like structures in white adipose tissue, although macrophage percentages were unchanged from OB-Res and lean mice. DIO mice also had decreased splenic CD4(+) T cells, elevated serum GM-CSF, and increased splenic CD11c(+) dendritic cells, but impaired dendritic cell stimulatory capacity (P < 0.05 vs. lean controls). These parameters were unaltered in OB-Res mice versus lean controls.

CONCLUSIONS

Diet-induced obesity results in alterations in immune and metabolic profiles that are distinct from effects caused by HFD alone.

Incidence of Type 1 Diabetes Is Not Increasing in a Population-Based Cohort in Olmsted County, Minnesota, USA

OBJECTIVES

To investigate the recent incidence of T1D in a US Midwestern county to determine whether this increase has been sustained and compare it with the incidence of celiac disease (CD) and also investigate the prevalence of CD, an associated autoimmune disease, within the cohort.

PATIENTS AND METHODS

A broad search strategy was used to identify all incident cases of T1D in Olmsted County, Minnesota, between January 1, 1994, and December 31, 2010, using the Rochester Epidemiology Project. Diagnosis and residency status were confirmed through the medical record. Incidence rates were directly standardized to the 2010 US population. Poisson regression was used to test for a change in incidence rate. Clinical charts were reviewed to confirm case status.

RESULTS

There were 233 incident cases of T1D. Directly adjusting for age and sex with respect to the 2010 US white population, the overall annual incidence of T1D was 9.2 (95% CI, 8.0-10.4) per 100,000 people per year among all ages and 19.9 (95% CI, 16.6-23.2) per 100,000 people per year for those younger than 20 years. There was no significant increase in the incidence of T1D over time (P=.45). Despite the overall stability in annual incidence, there was an initial increasing trend followed by a plateau. Of the 109 patients with T1D (47%) tested for CD, 12% (13) had biopsy-proven CD.

CONCLUSION

The incidence of T1D has stopped increasing in Olmsted County, Minnesota, in the most recent decade. Further studies are needed to confirm this finding and explore reasons for this plateau.

Where, How, and When: Positioning Posttranslational Modification Within Type 1 Diabetes Pathogenesis

Autoreactive T cells specific for islet autoantigens develop in type 1 diabetes (T1D) by escaping central as well as peripheral tolerance. The current paradigm for development of islet autoimmunity is just beginning to include the contribution of posttranslationally modified (PTM) islet autoantigens, for which the immune system may be ignorant rather than tolerant. As a result, PTM is the latest promising lead in the quest to understand how the break in peripheral tolerance occurs in T1D. However, it is not completely clear how, where, or when these modifications take place. Currently, only a few PTM antigens have been well-thought-out or identified in T1D, and methods for identifying and characterizing new PTM antigens are rapidly improving. This review will address both reported and potential new sources of modified islet autoantigens and discuss how islet neo-autoantigen generation may contribute to the development and progression of T1D.

Large Gliadin Peptides Detected in the Pancreas of NOD and Healthy Mice following Oral Administration

Gluten promotes type 1 diabetes in nonobese diabetic (NOD) mice and likely also in humans. In NOD mice and in non-diabetes-prone mice, it induces inflammation in the pancreatic lymph nodes, suggesting that gluten can initiate inflammation locally. Further, gliadin fragments stimulate insulin secretion from beta cells directly. We hypothesized that gluten fragments may cross the intestinal barrier to be distributed to organs other than the gut. If present in pancreas, gliadin could interact directly with the immune system and the beta cells to initiate diabetes development. We orally and intravenously administered 33-mer and 19-mer gliadin peptide to NOD, BALB/c, and C57BL/6 mice and found that the peptides readily crossed the intestinal barrier in all strains. Several degradation products were found in the pancreas by mass spectroscopy. Notably, the exocrine pancreas incorporated large amounts of radioactive label shortly after administration of the peptides. The study demonstrates that, even in normal animals, large gliadin fragments can reach the pancreas. If applicable to humans, the increased gut permeability in prediabetes and type 1 diabetes patients could expose beta cells directly to gliadin fragments. Here they could initiate inflammation and induce beta cell stress and thus contribute to the development of type 1 diabetes.

Diet, Microbiota and Immune System in Type 1 Diabetes Development and Evolution

Type 1 diabetes (T1D) is the second most frequent autoimmune disease in childhood. The long-term micro- and macro-vascular complications of diabetes are associated with the leading causes of disability and even mortality in young adults. Understanding the T1D etiology will allow the design of preventive strategies to avoid or delay the T1D onset and to help to maintain control after developing. T1D development involves genetic and environmental factors, such as birth delivery mode, use of antibiotics, and diet. Gut microbiota could be the link between environmental factors, the development of autoimmunity, and T1D. In this review, we will focus on the dietary factor and its relationship with the gut microbiota in the complex process involved in autoimmunity and T1D. The molecular mechanisms involved will also be addressed, and finally, evidence-based strategies for potential primary and secondary prevention of T1D will be discussed.

Flow cytometric gating for spleen monocyte and DC subsets: differences in autoimmune NOD mice and with acute inflammation

The role of antigen presenting cells (APCs) in the pathogenesis of autoimmune and other inflammatory diseases is now better understood due to advances in multicolor flow cytometry, gene expression analysis of APC populations, and functional correlation of mouse to human APC populations. A simple but informative nomenclature of conventional and plasmacytoid dendritic cell subsets (cDC1, cDC2, pDC) and monocyte-derived populations incorporates these advances, but accurate subset identification is critical. Ambiguous gating schemes and alterations of cell surface markers in inflammatory condition can make comparing results between studies difficult. Both acute inflammation, such as TLR-ligand stimulation, and chronic inflammation as found in mouse models of autoimmunity can alter DC subset gating. Here, we address these issues using in vivo CpG stimulation as an example of acute inflammation and the non-obese diabetic (NOD) mouse as a model of chronic inflammation.We provide a flow cytometric antibody panel and gating scheme that differentiate 2 monocytic and 3DC subsets in the spleen both at steady state and after CpG stimulation. Using this method, we observed differences in the composition of NOD DCs that have been previously reported, and newly identified increases in the number of NOD monocyte-derived DCs. Finally, we established a protocol for DC phosphoflow to measure the phosphorylation state of intracellular proteins, and use it to confirm functional differences in the identified subsets. Therefore, we present optimized methods for distinguishing monocytic and DC populations with and without inflammation and/or autoimmunity associated with NOD mice.

The Role of Gluten in Celiac Disease and Type 1 Diabetes

Celiac disease (CD) and type 1 diabetes (T1D) are autoimmune conditions in which dietary gluten has been proven or suggested to play a pathogenic role. In CD; gluten is established as the instigator of autoimmunity; the autoimmune process is halted by removing gluten from the diet; which allows for resolution of celiac autoimmune enteropathy and subsequent normalization of serological markers of the disease. However; an analogous causative agent has not yet been identified for T1D. Nevertheless; the role of dietary gluten in development of T1D and the potentially beneficial effect of removing gluten from the diet of patients with T1D are still debated. In this review; we discuss the comorbid occurrence of CD and T1D and explore current evidences for the specific role of gluten in both conditions; specifically focusing on current evidence on the effect of gluten on the immune system and the gut microbiota.

Rheumatoid arthritis-celiac disease relationship: joints get that gut feeling

Rheumatoid arthritis (RA) and celiac disease (CD) belong to the autoimmune disease family. Despite being separate entities they share multiple aspects. Epidemiologically they share comparable incidence environmental influences, associated antibodies and a recent incidental surge. They differ in their HLA pre-dispositions and specific predictive and diagnostic biomarkers. At the clinical level, celiac disease exhibits extra-intestinal rheumatic manifestations and RA gastrointestinal ones. Small bowel pathology exists in rheumatic patients. A trend towards responsiveness to a gluten free diet has been observed, ameliorating celiac rheumatic manifestations, whereas dietary interventions for rheumatoid arthritis remain controversial. Pathophysiologically, both diseases are mediated by endogenous enzymes in the target organs. The infectious, dysbiotic and increased intestinal permeability theories, as drivers of the autoimmune cascade, apply to both diseases. Contrary to their specific HLA pre-disposition, the diseases share multiple non-HLA loci. Those genes are crucial for activation and regulation of adaptive and innate immunity. Recently, light was shed on the interaction between host genetics and microbiota composition in relation to CD and RA susceptibility, connecting bugs and us and autoimmunity. A better understanding of the above mentioned similarities in the gut-joint inter-relationship, may elucidate additional facets in the mosaic of autoimmunity, relating CD to RA.