Pathophysiology Of Type 1 Diabetes Research Articles

Gene-environment interaction in the pathophysiology of type 1 diabetes.

Type 1 diabetes (T1D) is a complex metabolic autoimmune disorder that affects millions of individuals worldwide and often leads to significant comorbidities. However, the precise trigger of autoimmunity and disease onset remain incompletely elucidated. This integrative perspective article synthesizes the cumulative role of gene-environment interaction in the pathophysiology of T1D. Genetics plays a significant role in T1D susceptibility, particularly at the major histocompatibility complex (MHC) locus and cathepsin H (CTSH) locus. In addition to genetics, environmental factors such as viral infections, pesticide exposure, and changes in the gut microbiome have been associated with the development of T1D. Alterations in the gut microbiome impact mucosal integrity and immune tolerance, increasing gut permeability through molecular mimicry and modulation of the gut immune system, thereby increasing the risk of T1D potentially through the induction of autoimmunity. HLA class II haplotypes with known effects on T1D incidence may directly correlate to changes in the gut microbiome, but precisely how the genes influence changes in the gut microbiome, and how these changes provoke T1D, requires further investigations. These gene-environment interactions are hypothesized to increase susceptibility to T1D through epigenetic changes such as DNA methylation and histone modification, which in turn modify gene expression. There is a need to determine the efficacy of new interventions that target these epigenetic modifications such as "epidrugs", which will provide novel avenues for the effective management of T1D leading to improved quality of life of affected individuals and their families/caregivers.

NET Proteome in Established Type 1 Diabetes Is Enriched in Metabolic Proteins.

Type 1 diabetes (T1D) is a chronic autoimmune disease characterized by a T-cell-mediated destruction of the pancreatic insulin-producing beta cells. A growing body of evidence suggests that abnormalities in neutrophils and neutrophil extracellular trap (NET) formation (NETosis) are associated with T1D pathophysiology. However, little information is available on whether these changes are primary neutrophil defects or related to the environmental signals encountered during active disease. In the present work, the NET proteome (NETome) of phorbol 12-myristate 13-acetate (PMA)- and ionomycin-stimulated neutrophils from people with established T1D compared to healthy controls (HC) was studied by proteomic analysis. Levels of NETosis, in addition to plasma levels of pro-inflammatory cytokines and NET markers, were comparable between T1D and HC subjects. However, the T1D NETome was distinct from that of HC in response to both stimuli. Quantitative analysis revealed that the T1D NETome was enriched in proteins belonging to metabolic pathways (i.e., phosphoglycerate kinase, glyceraldehyde-3-phosphate dehydrogenase, and UTP-glucose-1-phosphate uridylyltransferase). Complementary metabolic profiling revealed that the rate of extracellular acidification, an approximate measure for glycolysis, and mitochondrial respiration were similar between T1D and HC neutrophils in response to both stimuli. The NETome of people with established T1D was enriched in metabolic proteins without an apparent alteration in the bio-energetic profile or dysregulated NETosis. This may reflect an adaptation mechanism employed by activated T1D neutrophils to avoid impaired glycolysis and consequently excessive or suboptimal NETosis, pivotal in innate immune defence and the resolution of inflammation.

Adequacy of knowledge of new medical graduates about diagnosis and management of children and adolescents with type 1 diabetes in a developing country

BackgroundKnowledge of diabetes by the graduate physicians had been reported to be deficient in many aspects of diagnosis and management of type 1 diabetes (T1D). This will reflect on patient care and quality of health services especially in limited-resources countries. Our aim was to assess knowledge of basic management of T1D in new medical graduates in Jordan.MethodsA questionnaire was developed to collect information concerning demographics and knowledge and was distributed in paper form and online using google forms. The knowledge was assessed using 28 questions on different aspects of the disease.ResultsA total of 358 new medicine graduates responded to the survey and female respondents were significantly higher than male respondents. Average number of lectures concerning diabetes during the medical school years was 3.92 ± 1.37. High knowledge scores were on pathophysiology of T1D, hypoglycemia, and certain aspects of diabetic ketoacidosis. Female gender, higher number of persons with T1D the participant had encountered during medical school, and good or excellent expected degree of self-knowledge of diabetes were associated with high knowledge score, p values = 0.01, 0.009, and < 0.001, respectively. Female gender and good or excellent expected degree of knowledge of diabetes predicted high knowledge score, p value = 0.008, and < 0.001, respectively.ConclusionGaps in knowledge of new medical graduates in certain T1D subjects exist. This can be corrected by many strategies including changes in curricula, elective courses, more clinical exposure, and interprofessional education. These measures must be evaluated for their short and long-term benefits.

Zinc transporter 8 haploinsufficiency protects against beta cell dysfunction in type 1 diabetes by increasing mitochondrial respiration

ObjectiveZinc transporter 8 (ZnT8) is a major humoral target in human type 1 diabetes (T1D). Polymorphic variants of Slc30A8, which encodes ZnT8, are also associated with protection from type 2 diabetes (T2D). The current study examined whether ZnT8 might play a role beyond simply being a target of autoimmunity in the pathophysiology of T1D. MethodsThe phenotypes of NOD mice with complete or partial global loss of ZnT8 were determined using a combination of disease incidence, histological, transcriptomic, and metabolic analyses. ResultsUnexpectedly, while complete loss of ZnT8 accelerated spontaneous T1D, heterozygosity was partially protective. In vivo and in vitro studies of ZnT8 deficient NOD.SCID mice suggested that the accelerated disease was due to more rampant autoimmunity. Conversely, beta cells in heterozygous animals uniquely displayed increased mitochondrial fitness under mild proinflammatory conditions. ConclusionsIn pancreatic beta cells and immune cell populations, Zn2+ plays a key role as a regulator of redox signaling and as an independent secondary messenger. Importantly, Zn2+ also plays a major role in maintaining mitochondrial homeostasis. Our results suggest that regulating mitochondrial fitness by altering intra-islet zinc homeostasis may provide a novel mechanism to modulate T1D pathophysiology.

1260-P: Gut Microbiome and Metabolic Activity in Type 1 Diabetes—An Analysis Based on the Presence of GADA

Background: Type 1 diabetes (T1D) progression is affected by the level of circulating glutamic acid decarboxylase antibody (GADA) , a main manifestation of islet autoimmunity. The gut microbiome and serum metabolites may contribute to islet autoimmunity in patients with T1D. Methods: We used radiobinding assay to measure GADA titers and identify the GADA+ ones (n=49) in 1T1D patients. The gut microbiome was assessed by 16S rRNA gene sequencing, and the serum metabolites were analysed with GC/MS. Results: T1D patients with and without GADA exhibited compositional and functional changes in the gut microbiome. Profiles in patients with GADA were distinct, with a significant increase in the abundances of Alistipes, Ruminococcus, Prevotella, Dialister, and marked depletion of Bacteroides, Bifidobacterium, Roseburia. For the untargeted serum metabolites, compared with those of GADA-, there were 54 significantly different metabolites with tryptophan metabolism: phenylalanine, and tyrosine and tryptophan biosynthesis decreased in patients with GADA. In addition, patients with GADA had elevated concentrations of Indole-3-acetic-acid, a marker of intestinal inflammation and epithelial damage. Co-occurrence network analysis revealed that gut microbiome disturbances affected tryptophan metabolism, suggesting that disturbed gut microbiome may mediate T1D immunotypes. Tryptophan metabolism may mediate inflammation in the pathogenesis and pathophysiology of T1D. Conclusion: These findings suggest that metabolites produced by the patients with GADA gut microbiota could cause damage to intestinal and systemic homeostasis and could be targeted for preventing the development of T1D. Disclosure T.Yue: None. X.Zheng: None. Z.Liu: None. Y.Ding: None. J.W.Wei: None. W.Xu: None. J.Weng: None. S.Luo: None. Funding the National Key r&amp;D Program (2017YFC1309600) the Anhui Provincial Natural science foundation (006212943003)

Novel Insights into the Immunotherapy-Based Treatment Strategy for Autoimmune Type 1 Diabetes

Type 1 diabetes (T1D) is an autoimmune disease characterized by the destruction of insulin-producing pancreatic β-cells by their own immune system, resulting in lifelong insulin deficiency. Continuous exogenous insulin replacement therapy is the current standard of care for T1D. Transplantation of primary pancreatic islets or the entire pancreas is a viable remedy for managing patients with autoimmune T1D. However, this strategy is not feasible due to several obstacles, including a scarcity of donors, islet cells, and poor vascular engraftment of islets post-transplantation, as well as the need for prolonged immune suppression. Innovative approaches must be developed to counteract pancreatic β-cell destruction and salvage endogenic insulin production, thereby regulating blood glucose levels. This review includes an overview of autoimmune T1D, immune cells involved in T1D pathophysiology, and immunotherapy-based strategies to treat and prevent autoimmune T1D. Recent immunotherapy progress toward targeting pancreatic islet-specific immune pathways tangled tolerance has fueled the advancement of therapies that may allow for the prevention or reversal of this autoimmune T1D while avoiding other adverse reactions associated with the previous attempt, which was mostly immunosuppressive. As a result, significant efforts are currently underway to improve the efficacy of immunotherapy-based approaches by leveraging the beneficial actions of immune cells, specifically effector CD4+, CD8+, and regulatory T cells. This review will provide an overview of currently available immune-based therapeutic options for T1D and will examine the growing evidence that supports the use of immune cell-based approaches to improve therapeutic outcomes in the prevention or reversal of autoimmune T1D.

The Role of Stem Cells in the Treatment of Type 1 Diabetes Mellitus and Associated Complications

Type 1 diabetes (T1D) affects many individuals worldwide and is associated with multiple long-term complications. The underlying pathophysiology of T1D involves an autoimmune process that leads to destruction of pancreatic β-islet cells, which are the sole cells responsible for producing the body’s insulin. Thus, the current recommended treatment for T1D is insulin therapy, which requires continuous awareness and monitoring throughout the day, placing a great deal of stress and responsibility on patients. Various modalities are under investigation to provide alternatives to treatment, or even a cure. Adult endogenous progenitor cells have been studied as one potential therapy for patients with T1D due to their ability to prevent an allogenic immune response in addition to an autoimmune response. Additionally, pancreatic ductal cells and bone marrow stem cells served as one of the first areas of research that demonstrated self-progenitor cells could regenerate pancreatic islet cells. A major limitation to stem cell therapy success is the risk of graft rejection. However, altering immune cell composition and creating physical barriers to protect the implanted cells from attack has been one successful solution to this by circumventing the pernicious immune response that is characteristic of T1D. Other limitations of these therapies include teratoma risk and the inability to reproduce the required signaling environment for cell differentiation ex vivo. Furthermore, stem cell therapy has shown promise in its applications for treatment of diabetes-associated complications including diabetic retinopathy, diabetic nephropathy, and diabetic neuropathy. This article critically reviews previous research and current progress toward stem cell treatment options for patients with T1D.

Identifying Changes in Peripheral Lymphocyte Subpopulations in Adult Onset Type 1 Diabetes.

T- and B-lymphocytes play an important role in the pathogenesis of type 1 diabetes (T1D), a chronic disease caused by the autoimmune destruction of the insulin-producing cells in the pancreatic islets. Flow cytometry allows their characterization in peripheral blood, letting to investigate changes in cellular subpopulations that can provide insights in T1D pathophysiology. With this purpose, CD4+ and CD8+ T cells (including naïve, central memory, effector memory and terminally differentiated effector (TEMRA), Th17 and Tregs) and B cells subsets (naïve, unswitched memory, switched memory and transitional B cells) were analysed in peripheral blood of adult T1D patients at disease onset and after ≥2 years using multiparametric flow cytometry. Here we report changes in the percentage of early and late effector memory CD4+ and CD8+ T cells as well as of naïve subsets, regulatory T cells and transitional B cells in peripheral blood of adult patients at onset of T1D when compared with HD. After 2 years follow-up these changes were maintained. Also, we found a decrease in percentage of Th17 and numbers of T cells with baseline. In order to identify potential biomarkers of disease, ROC curves were performed being late EM CD4 T cell subset the most promising candidate. In conclusion, the observed changes in the percentage and/or absolute number of lymphocyte subpopulations of adult T1D patients support the hypothesis that effector cells migrate to the pancreas and this autoimmune process perseveres along the disease. Moreover, multiparametric flow allows to identify those subsets with potential to be considered biomarkers of disease.

Partners in Crime: Beta-Cells and Autoimmune Responses Complicit in Type 1 Diabetes Pathogenesis.

Type 1 diabetes (T1D) is an autoimmune disease characterized by autoreactive T cell-mediated destruction of insulin-producing pancreatic beta-cells. Loss of beta-cells leads to insulin insufficiency and hyperglycemia, with patients eventually requiring lifelong insulin therapy to maintain normal glycemic control. Since T1D has been historically defined as a disease of immune system dysregulation, there has been little focus on the state and response of beta-cells and how they may also contribute to their own demise. Major hurdles to identifying a cure for T1D include a limited understanding of disease etiology and how functional and transcriptional beta-cell heterogeneity may be involved in disease progression. Recent studies indicate that the beta-cell response is not simply a passive aspect of T1D pathogenesis, but rather an interplay between the beta-cell and the immune system actively contributing to disease. Here, we comprehensively review the current literature describing beta-cell vulnerability, heterogeneity, and contributions to pathophysiology of T1D, how these responses are influenced by autoimmunity, and describe pathways that can potentially be exploited to delay T1D.

Can the FUT2 Non-secretor Phenotype Associated With Gut Microbiota Increase the Children Susceptibility for Type 1 Diabetes? A Mini Review.

The global toll of type 1 diabetes (T1D) has steadily increased over the last decades. It is now widely acknowledged that T1D pathophysiology is more complex than expected. Indeed, a multifaceted interplay between genetic, metabolic, inflammatory and environmental factors exists that leads to heterogeneous clinical manifestations across individuals. Children with non-secretor phenotype and those affected by T1D share low abundance of bifidobacteria, low content of short-chain fatty acids, intestinal phosphatase alkaline and a high incidence of inflammatory bowel diseases. In this context, host-gut microbiota dyad may represent a relevant contributor to T1D development and progression due to its crucial role in shaping host immunity and susceptibility to autoimmune conditions. The FUT2 gene is responsible for the composition and functional properties of glycans in mucosal tissues and bodily secretions, including human milk. FUT2 polymorphisms may profoundly influence gut microbiota composition and host susceptibility to viral infections and chronic inflammatory disease. In this minireview, the possible interplay between mothers' phenotype, host FUT2 genetic background and gut microbiota composition will be discussed in perspective of the T1D onset. The study of FUT2-gut microbiota interaction may add a new piece on the puzzling T1D etiology and unveil novel targets of intervention to contrast T1D development and progression. Dietary interventions, including the intake of α-(1, 2)-fucosyl oligosaccharides in formula milk and the use of specific prebiotics and probiotics, could be hypothesized.

Beta‐cell‐specific Loss of the Inhibitory G protein, Gαz, has Sex‐dependent Effects on Development and Pathophysiology of Type 1 Diabetes

The mechanisms that underlie the beta‐cell pathophysiology of Type 1 Diabetes (T1D) are not fully understood. Our lab has discovered a role for the unique inhibitory G‐protein, Gαz, in beta‐cell function, survival, and replication in both normal conditions and those of pathological stress. Gαz, when acting as a canonical inhibitory G‐protein, reduces production of cAMP through inhibition of adenylate cyclase. Cyclic AMP acts as essential player in the amplification of glucose‐stimulated insulin secretion, while also mediating pathways that regulate beta‐cell death and replication. Previous work in our lab has shown that non‐obese diabetic (NOD) mice with global loss of Gαz are protected from developing T1D‐like hyperglycemia through increased beta‐cell function, increased beta‐cell replication, and decreased beta‐cell death. In order to determine if Gαz in the beta‐cell was solely responsible for the protected phenotype, we generated a beta‐cell‐specific Gαzknockout mouse by breeding GzFlox/Flox mice with Rat Insulin Promoter (RIP) driven CreHerrmice, on the NOD background for more than 10 generations. Experimental mice were sNP genotyped to ensure preservation of NOD loci. Weekly random‐fed blood glucose measurements were taken beginning at weaning. Loss of beta‐cell Gαz(GαzβKO), only provided a modest protection against diabetes development; 69% of Gαz βKO females remained euglycemic over the first 30 weeks of life compared to 59% in Cre+ NOD controls. Consistent with this phenotype, neither pancreases from Gαzβ‐cell‐KO males nor females had increased beta‐cell fractional area as compared to Cre+ controls. Overall, both euglycemic Gαzβ‐cell‐KO males and females had improved glucose tolerance at 12 weeks of age, with this effect persisting at 28 weeks of age only in females. Yet, the mean insulitis score at 28 weeks‐of‐age was dramatically reduced in GαzβKO males only, and this score was strongly correlated with 28‐week glucose tolerance test AUC. The effects of Gαzβ‐cell‐KO on plasma insulin and ex vivo islet insulin secretion are also differentially regulated by sex: effects that appear to correlate with baseline expression of the constitutively‐active splice variant of the Gαz coupled EP3 receptor. Finally, changes in intra‐islet hormone production and secretion in full‐body vs. beta‐cell‐specific Gαz‐KO mice provide a potential mechanism for the incomplete protection from hyperglycemia in Gαzβ‐cell‐KO mice. Overall, our results show a divergent, sex‐dependent role for beta‐cell Gαz in T1D pathophysiology and implicate Gαz as a hub of intra‐islet cell‐cell signaling.

A Fun Way to Learn About Diabetes: Using Therapeutic Play in a Brazilian Camp

PurposeUnderstanding disease mechanisms inside the body is crucial to engage youth with type 1 diabetes (T1D) in self-care behaviors. This study describes how Instructional Therapeutic Play (ITP) group sessions held by nurses in a Brazilian camp can enhance youth's understanding about T1D. Design and methodsYouth with T1D participated in video recorded ITP group sessions guided by the Sensitive Creative Method. First, participants were asked to create an artistic production based upon the query “What happens in the body of a young person who has diabetes?”. They described their drawings and shared information, providing opportunities to discuss T1D pathophysiology. Second, campers were told a story about a child who had T1D onset using a rag doll and illustrative figures. Participants were asked to create a second artistic production based upon the same initial query. Finally, campers had another presentation of the drawings, discussion, and sharing through the question “How did the story told help you understand your diabetes?” Transcriptions of ITP sessions were submitted to thematic analysis. ResultsTwenty participants (9-17yo) were assigned to age/gender matched groups. Four themes were built: Designing insulin production; Experiencing the glycemic vigilance in diabetes management; The ITP session as a safe space to share challenges with nurses and peers; and Unraveling the myths of diabetes with the ITP session. ConclusionTherapeutic play sessions enhanced youth's knowledge and unraveled myths of T1D pathophysiology. Practice implicationsITP sessions can be developed by nurses in order to deliver age-appropriate diabetes education to pediatric patients.

From immunohistological to anatomical alterations of human pancreas in type 1 diabetes: New concepts on the stage.

The histological analysis of human pancreatic samples in type 1 diabetes (T1D) has been proven essential to move forward in the evaluation of in situ events characterizing T1D. Increasing availability of pancreatic tissues collected from diabetic multiorgan donors by centralized biorepositories, which have shared tissues among researchers in the field, has allowed a deeper understanding of T1D pathophysiology, using novel immunohistological and high-throughput methods. In this review, we provide a comprehensive update of the main recent advancements in the characterization of cellular and molecular events involving endocrine and exocrine pancreas as well as the immune system in the onset and progression of T1D. Additionally, we underline novel elements, which provide evidence that T1D pathological changes affect not only islet β-cells but also the entire pancreas.

OR17-6 Parenteral Cephalosporins and Glucose During the Neonatal Period Are Associated with Pediatric Type 1 Diabetes Development

Background: The incidence of both the survival of premature infants and type 1 diabetes (T1D) is rising worldwide. The pathophysiology of T1D depends on the differentiation of cellular and humoral immune systems recognition of the self, which occurs during the neonatal period and is influenced by environmental exposures. Aim: To assess the association between nutritional, antibiotic and parenteral exposures during the neonatal period and the development of pediatric T1D. Methods: a multicenter, paired case-control study. Preterm subjects who were born between 1990-2013, and developed T1D before the age of 18 years (T1D group), were paired with subjects who didn't develop TID (Control group) at a ratio of 1:3 by: gender, gestational age (GA), month of birth and birth medical center . This preterm population is a model of a neonatal population with strictly meticulous follow up data available in all medical centers in Israel. Data retrieved from charts included maternal history, delivery method, ethnic origin, weight for GA, NICU length of hospitalization, medications, parenteral fluid types, feeding modes and their timing. Univariate and multivariate analysis via Generalized Estimating Equations (GEE) using a binary logistic regression model were performed to evaluate the association between T1D and the assessed exposures. Results: T1D group included 52 subjects, 26 males, median GA 35 (26-36), mean BW 2307.6±534.5. Control group included 133 subjects, 69 males. median GA 35 (27-36), mean BW 2094.5±484.1. In univariate analysis, the odds ratio (OR) for T1D increased with each extra 100 grams in BW (OR 1.13, 95%CI 1.057-1.206, p < 0.001), later day of parenteral glucose initiation (OR 1.61, 95%CI 1.05-2.48, p 0.03), and parenteral cephalosporines initiated beyond the first week of life (OR 3.25, 95%CI 1.504-7.04, p 0.003). Treatment with narrow spectrum beta-lactam antibiotics during the first week of life was associated with lower risk for T1D development (OR 0.23, 95%CI 0.12-0.47, p < 0.001). Multivariate analysis revealed significant association between both treatment with cephalosporins beyond the first week of life and later day of parenteral glucose initiation and the development of pediatric T1D (OR 6.49, 95%CI 1.54-27.44, p 0.011 and OR 1.61, 95%CI 1.05-2.48, p 0.002, respectively). No association with feeding modality (oral/nasogastric), timing and type of feeding (breast or bottle) was found. Conclusions: This is the first report indicating a significant association between parenteral exposure and timing of variable antibiotic treatments and glucose solution administration during the neonatal period with development of T1D. This report indicates the need for a larger study to conclude clinical implications of management and exposure to these substances during the neonatal period and its relevance to the neonatal microbiome.

Multiplexed In Situ Imaging Mass Cytometry Analysis of the Human Endocrine Pancreas and Immune System in Type 1 Diabetes

The interaction between the immune system and endocrine cells in the pancreas is crucial for the initiation and progression of type 1 diabetes (T1D). Imaging mass cytometry (IMC) enables multiplexed assessment of the abundance and localization of more than 30 proteins on the same tissue section at 1-μm resolution. Herein, we have developed a panel of 33 antibodies that allows for the quantification of key cell types including pancreatic exocrine cells, islet cells, immune cells, and stromal components. We employed this panel to analyze 12 pancreata obtained from donors with clinically diagnosed T1D and 6 pancreata from non-diabetic controls. In the pancreata from donors with T1D, we simultaneously visualized significant alterations in islet architecture, endocrine cell composition, and immune cell presentation. Indeed, we demonstrate the utility of IMC to investigate complex events on the cellular level that will provide new insights on the pathophysiology of T1D.

Beta‐cell‐specific loss of the inhibitory G protein, Gαz, prevents development of Type 1 Diabetes in NOD mice.

The mechanisms that underlie the beta‐cell pathophysiology of Type 1 Diabetes (T1D) are not fully understood. Our lab has discovered a role for the unique inhibitory G‐protein, Gαz, in beta‐cell function, survival, and replication in both normal conditions and those of pathological stress. Gαz, when acting as a canonical inhibitory G‐protein, reduces production of cyclic adenosine monophosphate (cAMP) through inhibition of adenylate cyclase. cAMP acts as essential player in the amplification of glucose‐stimulated insulin secretion, while also mediating pathways that regulate beta‐cell death and replication. We've shown previously that removal of this inhibitory protein is sufficient to promote insulin secretion, beta‐cell growth and survival using chemically‐induced beta‐cell death and diabetes in C57BL/6J mice. Previous work in our lab has also shown that non‐obese diabetic (NOD) mice with global loss of Gαz are protected from developing T1D‐like hyperglycemia through a multi‐faceted maintenance of beta‐cell health. Whole body Gαznull animals exhibited a significant increase in beta‐cell function and replication and decreased beta‐cell death. Most interestingly, islets from Gαz‐null NOD animals exhibited a marked decrease in immune infiltration. In order to determine if Gαz in the beta‐cell was responsible for the protected phenotype, we generated a beta‐cell‐specific Gαz knockout by breeding Gz Flox/Flox mice with Rat Insulin Promoter (RIP) driven CreHerr mice, on the NOD background. After 10 generations of backcrossing, we began by determining if loss of beta cell Gαz was sufficient to protect NOD animals from developing T1D‐like hyperglycemia. Weekly random‐fed blood glucose measurements were taken beginning at weaning. In the initial cohort, we saw a 12% penetrance of hyperglycemia in male Cre‐positive NOD mice and a 23% penetrance of hyperglycemia in female Cre‐positive NOD mice by 30 weeks of age. In contrast, Gαzβ‐cell‐KO males and females were entirely protected from developing hyperglycemia during this period. Despite this stark contrast, fasting blood glucose was no different between genotypes, grouped by sex, at either 12 or 28 weeks of age. Glucose tolerance was also not different between Cre‐positive NOD controls and Gαzβ‐cell‐KO animals. Experiments are ongoing to further investigate other facets of beta‐cell health, including function, replication and survival. Additionally, it will be crucial to evaluate the presence and extent of insulitis in our Gαzβ‐cell‐KO animals. Thus far, our results show a critical role for beta‐cell Gαz in promoting T1D pathophysiology, although the precise mechanism remains to be determined.Support or Funding InformationNIH F31 DK109698 to RFThis abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Dysfunctional autophagy following exposure to pro-inflammatory cytokines contributes to pancreatic \u03b2-cell apoptosis

Type 1 diabetes (T1D) results from β-cell destruction due to concerted action of both innate and adaptive immune responses. Pro-inflammatory cytokines, such as interleukin-1β and interferon-γ, secreted by the immune cells invading islets of Langerhans, contribute to pancreatic β-cell death in T1D. Cytokine-induced endoplasmic reticulum (ER) stress plays a central role in β-cell demise. ER stress can modulate autophagic response; however, no study addressed the regulation of autophagy during the pathophysiology of T1D. In this study, we document that cytokines activate the AMPK-ULK-1 pathway while inhibiting mTORC1, which stimulates autophagy activity in an ER stress-dependent manner. On the other hand, time-course analysis of LC3-II accumulation in autophagosomes revealed that cytokines block the autophagy flux in an ER stress independent manner, leading to the formation of large dysfunctional autophagosomes and worsening of ER stress. Cytokines rapidly impair lysosome function, leading to lysosome membrane permeabilization, Cathepsin B leakage and lysosomal cell death. Blocking cathepsin activity partially protects against cytokine-induced or torin1-induced apoptosis, whereas blocking autophagy aggravates cytokine-induced CHOP overexpression and β-cell apoptosis. In conclusion, cytokines stimulate the early steps of autophagy while blocking the autophagic flux, which aggravate ER stress and trigger lysosomal cell death. Restoration of autophagy/lysosomal function may represent a novel strategy to improve β-cell resistance in the context of T1D.

Association between type 1, type 2 cytokines, diabetic autoantibodies and 25-hydroxyvitamin D in children with type 1 diabetes.

Vitamin D may play a role in the pathogenesis of type 1 diabetes (T1D). The aim of the current study was to determine the possible association between 25-hydroxyvitamin D [25(OH)D] levels and circulating levels of type 1 and type 2 cytokines, as well as the pathophysiology of T1D in children. A total of 250 T1D patients and 250 sex- and age-matched T1D-free controls were screened for 25(OH)D, hemoglobin A1c (HbA1c), type 1 and type 2 cytokines, C-reactive protein (CRP) and bone mineral metabolism, as well as antibodies against insulin, glutamic acid decarboxylase (anti-GAD 65) and islet cells. Our data showed that the plasma level of 25(OH)D was significantly lower in T1D patients and that there was a significant negative correlation between 25(OH)D levels and HbA1c values. There was a significant association between deficient levels of 25(OH)D and higher levels of cytokines (IFN-γ, TNF-α, IL-6, IL-1β, IL-4 and IL-10) and CRP. Total blood hemoglobin, the hematocrit percentage, body mass index SDS values, phosphate and magnesium levels were significantly lower in T1D patients than in T1D-free subjects. The levels of parathyroid hormone and alkaline phosphatase were significantly higher in T1D patients. Higher levels of cytokines were significantly associated with deficient levels of 25(OH)D. Moreover, in T1D patients, higher levels of islet antibodies, anti-GAD antibodies and anti-insulin antibodies were significantly associated with deficient levels of 25(OH)D. In type 1 diabetic children, deficient levels of 25(OH)D are associated with high levels of HbA1c, circulatory cytokines and antibody markers.

MicroRNAs: Novel Players in the Dialogue between Pancreatic Islets and Immune System in Autoimmune Diabetes.

MicroRNAs are small noncoding RNA molecules that regulate gene expression in all cell types. Therefore, these tiny noncoding RNA molecules are involved in a wide range of biological processes, exerting functional effects at cellular, tissue, and organ level. In pancreatic islets of Langerhans, including beta-cells, microRNAs are involved in cell differentiation as well as in insulin secretion, while in immune cells they have been shown to play pivotal roles in development, activation, and response to antigens. Indeed, it is not surprising that microRNA alterations can lead to the development of several diseases, including type 1 diabetes (T1D). Type 1 diabetes is the result of a selective autoimmune destruction of insulin-producing beta-cells, characterized by islet inflammation (insulitis), which leads to chronic hyperglycemia. Given the growing importance of microRNA in the pathophysiology of T1D, the aim of this review is to summarize the most recent data on the potential involvement of microRNAs in autoimmune diabetes. Specifically, we will focus on three different aspects: (i) microRNAs as regulators of immune homeostasis in autoimmune diabetes; (ii) microRNA expression in pancreatic islet inflammation; (iii) microRNAs as players in the dialogue between the immune system and pancreatic endocrine cells.

Serological autoantibody profiling of type 1 diabetes by protein arrays

The need for biomarkers that illuminate the pathophysiology of type 1 diabetes (T1D), enhance early diagnosis and provide additional avenues for therapeutic intervention is well recognized in the scientific community. We conducted a proteome-scale, two-stage serological AAb screening followed by an independent validation study. In the first stage, the immunoreactivity was compared between T1D cases and healthy controls against ~6000 human proteins using the nucleic acid programmable protein array (NAPPA). Genes identified with higher signal intensities in patients were challenged with a larger sample set during the second stage. Statistical analysis revealed 26 novel autoantigens and a known T1D-associated autoantigen. During validation, we verified the presence of AAbs to dual specificity tyrosine-phosphorylation-regulated kinase 2 (DYRK2) using the Luciferase ImmunoPrecipitation System (LIPS) assay (36% sensitivity, 98% specificity). The AUC for a combination of DYRK2A and the classical T1D AAb IA-2A was 0.90 compared to 0.72 for DYRK2A and 0.64 for IA-2A alone. This is the first systematic screening for seroreactivity against a large number of human proteins in T1D patients. We demonstrated the application of protein microarrays to identify novel autoantigens in T1D, expanded the current T1D "autoantigenome" and help fulfill the goal of searching for novel biomarker candidates for T1D. Protein microarrays provide a high-throughput platform that enables the profiling of serum antibodies to a large number of protein antigens. The value of AAb biomarkers in diagnosis, prognosis and treatment is well recognized in autoimmune diseases including T1D. We performed a systematic screening for new T1D-associated autoantigens by adapting the innovative protein array platform NAPPA. We believe that the discovery in this study will add information on candidate autoantigens that could potentially improve the diagnosis and help uncover the pathophysiology of T1D. The successful use of NAPPA for T1D AAb profiling will open the window for larger studies including more human antigen genes and other autoimmune diseases.