Early and quantal (by litter) expression of insulin autoantibodies in the nonobese diabetic mice predict early diabetes onset

Decoding the immune dance: Unraveling the interplay between beta cells and type 1 diabetes

BACKGROUND

Type 1 diabetes (T1D) is an autoimmune disease characterized by the specific destruction of insulin-producing beta cells in the pancreas by the immune system, including CD4 cells which orchestrate the attack and CD8 cells which directly destroy the beta cells, resulting in the loss of glucose homeostasis.

SCOPE OF REVIEW

This comprehensive document delves into the complex interplay between the immune system and beta cells, aiming to shed light on the mechanisms driving their destruction in T1D. Insights into the genetic predisposition, environmental triggers, and autoimmune responses provide a foundation for understanding the autoimmune attack on beta cells. From the role of viral infections as potential triggers to the inflammatory response of beta cells, an intricate puzzle starts to unfold. This exploration highlights the importance of beta cells in breaking immune tolerance and the factors contributing to their targeted destruction. Furthermore, it examines the potential role of autophagy and the impact of cytokine signaling on beta cell function and survival.

MAJOR CONCLUSIONS

This review collectively represents current research findings on T1D which offers valuable perspectives on novel therapeutic approaches for preserving beta cell mass, restoring immune tolerance, and ultimately preventing or halting the progression of T1D. By unraveling the complex dynamics between the immune system and beta cells, we inch closer to a comprehensive understanding of T1D pathogenesis, paving the way for more effective treatments and ultimately a cure.

Cytokine-Induced Myeloid-Derived Suppressor Cells Demonstrate Their Immunoregulatory Functions to Prolong the Survival of Diabetic Mice

Type 1 diabetes is an inflammatory state. Myeloid-derived suppressive cells (MDSCs) originate from immature myeloid cells and quickly expand to control host immunity during infection, inflammation, trauma, and cancer. This study presents an ex vivo procedure to develop MDSCs from bone marrow cells propagated from granulocyte-macrophage-colony-stimulating factor (GM-CSF), interleukin (IL)-6, and IL-1β cytokines expressing immature morphology and high immunosuppression of T-cell proliferation. The adoptive transfer of cytokine-induced MDSCs (cMDSCs) improved the hyperglycemic state and prolonged the diabetes-free survival of nonobese diabetic (NOD) mice with severe combined immune deficiency (SCID) induced by reactive splenic T cells harvested from NOD mice. In addition, the application of cMDSCs reduced fibronectin production in the renal glomeruli and improved renal function and proteinuria in diabetic mice. Moreover, cMDSCs use mitigated pancreatic insulitis to restore insulin production and reduce the levels of HbA1c. In conclusion, administering cMDSCs propagated from GM-CSF, IL-6, and IL-1β cytokines provides an alternative immunotherapy protocol for treating diabetic pancreatic insulitis and renal nephropathy.

Human hypoimmune primary pancreatic islets avoid rejection and autoimmunity and alleviate diabetes in allogeneic humanized mice

Transplantation of allogeneic pancreatic donor islets has successfully been performed in selected patients with difficult-to-control insulin-dependent diabetes and impaired awareness of hypoglycemia (IAH). However, the required systemic immunosuppression associated with this procedure prevents this cell replacement therapy from more widespread adoption in larger patient populations. We report the editing of primary human islet cells to the hypoimmune HLA class I- and class II-negative and CD47-overexpressing phenotype and their reaggregation into human HIP pseudoislets (p-islets). Human HIP p-islets were shown to survive, engraft, and ameliorate diabetes in immunocompetent, allogeneic, diabetic humanized mice. HIP p-islet cells were further shown to avoid autoimmune killing in autologous, diabetic humanized autoimmune mice. The survival and endocrine function of HIP p-islet cells were not impaired by contamination of unedited or partially edited cells within the p-islets. HIP p-islet cells were eliminated quickly and reliably in this model using a CD47-targeting antibody, thus providing a safety strategy in case HIP cells exert toxicity in a future clinical setting. Transplantation of human HIP p-islets for which no immunosuppression is required has the potential to lead to wider adoption of this therapy and help more diabetes patients with IAH and history of severe hypoglycemic events to achieve insulin independence.

Rodent models for diabetes

Diabetes mellitus (DM) is associated with many health complications and is potentially a morbid condition. As prevalence increases at an alarming rate around the world, research into new antidiabetic compounds with different mechanisms is the top priority. Therefore, the preclinical experimental induction of DM is imperative for advancing knowledge, understanding pathogenesis, and developing new drugs. Efforts have been made to examine recent literature on the various induction methods of Type I and Type II DM. The review summarizes the different in vivo models of DM induced by chemical, surgical, and genetic (immunological) manipulations and the use of pathogens such as viruses. For good preclinical assessment, the animal model must exhibit face, predictive, and construct validity. Among all reported models, chemically induced DM with streptozotocin was found to be the most preferred model. However, the purpose of the research and the outcomes to be achieved should be taken into account. This review was aimed at bringing together models, benefits, limitations, species, and strains. It will help the researcher to understand the pathophysiology of DM and to choose appropriate animal models.

β-Cell Cre Expression and Reduced Ins1 Gene Dosage Protect Mice From Type 1 Diabetes

A central goal of physiological research is the understanding of cell-specific roles of disease-associated genes. Cre-mediated recombineering is the tool of choice for cell type-specific analysis of gene function in preclinical models. In the type 1 diabetes (T1D) research field, multiple lines of nonobese diabetic (NOD) mice have been engineered to express Cre recombinase in pancreatic β cells using insulin promoter fragments, but tissue promiscuity remains a concern. Constitutive Ins1tm1.1(cre)Thor (Ins1Cre) mice on the C57/bl6-J background have high β-cell specificity with no reported off-target effects. We explored whether NOD:Ins1Cre mice could be used to investigate β-cell gene deletion in T1D disease modeling. We studied wild-type (Ins1WT/WT), Ins1 heterozygous (Ins1Cre/WT or Ins1Neo/WT), and Ins1 null (Ins1Cre/Neo) littermates on a NOD background. Female Ins1Neo/WT mice exhibited significant protection from diabetes, with further near-complete protection in Ins1Cre/WT mice. The effects of combined neomycin and Cre knockin in Ins1Neo/Cre mice were not additive to the Cre knockin alone. In Ins1Neo/Cre mice, protection from diabetes was associated with reduced insulitis at age 12 weeks. Collectively, these data confirm previous reports that loss of Ins1 alleles protects NOD mice from diabetes development and demonstrates, for the first time, that Cre itself may have additional protective effects. This has important implications for the experimental design and interpretation of preclinical T1D studies using β-cell-selective Cre in NOD mice.

Potentialities of Gene Therapy in Pediatric Endocrinology

Gene therapy has become an appealing therapeutic option in many pediatric fields, including endocrinology. Unlike traditional drugs based on molecules that require repeated and frequent burdensome administrations, a single genetic therapeutic intervention may allow durable and curative clinical benefits. Although this highly innovative technology holds a great promise for the treatment of monogenic diseases, its clinical applications in the field of endocrinology have been so far challenging. In this review, we will discuss various ex vivo and in vivo approaches and potential applications of gene addition and gene editing approaches for treating hyperfunctional and hypofunctional endocrine diseases due to intrinsic defects or autoimmune origin. We will focus on the recent advances in gene therapy approaches aimed at treating type 1 diabetes and monogenic forms of endocrinopathies such as growth hormone deficiency, congenital adrenal hyperplasia, diabetes insipidus, IPEX, as well as their trends and future directions.

Diagnosis and treatment of type 1 diabetes at the dawn of the personalized medicine era

Type 1 diabetes affects millions of people globally and requires careful management to avoid serious long-term complications, including heart and kidney disease, stroke, and loss of sight. The type 1 diabetes patient cohort is highly heterogeneous, with individuals presenting with disease at different stages and severities, arising from distinct etiologies, and overlaying varied genetic backgrounds. At present, the “one-size-fits-all” treatment for type 1 diabetes is exogenic insulin substitution therapy, but this approach fails to achieve optimal blood glucose control in many individuals. With advances in our understanding of early-stage diabetes development, diabetes stratification, and the role of genetics, type 1 diabetes is a promising candidate for a personalized medicine approach, which aims to apply “the right therapy at the right time, to the right patient”. In the case of type 1 diabetes, great efforts are now being focused on risk stratification for diabetes development to enable pre-clinical detection, and the application of treatments such as gene therapy, to prevent pancreatic destruction in a sub-set of patients. Alongside this, breakthroughs in stem cell therapies hold great promise for the regeneration of pancreatic tissues in some individuals. Here we review the recent initiatives in the field of personalized medicine for type 1 diabetes, including the latest discoveries in stem cell and gene therapy for the disease, and current obstacles that must be overcome before the dream of personalized medicine for all type 1 diabetes patients can be realized.

Investigation of type 1 diabetes in NOD mice knockout for the osteopontin gene

OBJECTIVE

Type 1 diabetes onset is preceded by a pre-inflammatory stage leading to insulitis and followed by targeted destruction of the insulin-producing beta cells of the pancreas. Osteopontin (OPN) is a secreted phosphoprotein with cytokine properties, implicated in many physiological and pathological processes, including infection and autoimmunity. We have previously identified up-regulated osteopontin transcripts in the pancreatic lymph nodes of the NOD (Non-Obese Diabetic) mouse at the pre-diabetic stages. Investigating the underlined disease initiating mechanisms may well contribute to the development of novel preventive therapies. Our aim was to construct opn null mice in a NOD autoimmune-prone genetic background and address the pathogenic or protective role of the osteopontin molecule in the early stages of type 1 diabetes.

METHODS

We generated opn null mutant mice in a NOD genetic background by serial backcrossing to the existing C57BL/6 opn knockout strain. The presence of opn wild type or null alleles in the congenic lines was evaluated by PCR amplification. We used NOD opn-null mice to assess the phenotypic evolution of type 1 diabetes. The presence of OPN in the serum was evaluated by ELISA and by immunostaining on the mouse tissues. The primary gene structure of the NOD opn encoding gene and protein sequences were compared to the known alleles of other mouse strains. Evaluation of Single Nucleotide Polymorphisms (SNPs) variation between opn alleles of the opn gene is reported.

RESULTS

In the absence of OPN, type 1 diabetes is accelerated, suggesting a protective role of this cytokine on the insulin-producing cells of the pancreatic islets. Conversely, in the presence of the opn gene, an increase of the OPN protein in the serum of young NOD mice indicates that this molecule might be involved in the immune regulatory events taking place at early stages, prior to disease onset. Our data support that OPN acts as a positive regulator of the early islet autoimmune damage, possibly by a shift of the steady-state of T1D pathogenesis. We report that the OPN protein structure of the NOD/ShiLtJ strain corresponds to the a-type allele of the osteopontin gene. Comparative analysis of the single nucleotide polymorphisms between the a-type and b-type alleles indicates that the majority of variations are within the non-coding regions of the gene.

CONCLUSIONS

The construction of opn null mice in an autoimmune genetic background (NOD.B6.Cg-spp1^-/-) provides important tools for the study of the implication of the OPN in type 1 diabetes, offering the possibility to address the significance of this molecule as an early marker of the disease and as a therapeutic agent in preclinical studies.

The Role of NOD Mice in Type 1 Diabetes Research: Lessons from the Past and Recommendations for the Future

For more than 35 years, the NOD mouse has been the primary animal model for studying autoimmune diabetes. During this time, striking similarities to the human disease have been uncovered. In both species, unusual polymorphisms in a major histocompatibility complex (MHC) class II molecule confer the most disease risk, disease is caused by perturbations by the same genes or different genes in the same biological pathways and that diabetes onset is preceded by the presence of circulating autoreactive T cells and autoantibodies that recognize many of the same islet antigens. However, the relevance of the NOD model is frequently challenged due to past failures translating therapies from NOD mice to humans and because the appearance of insulitis in mice and some patients is different. Nevertheless, the NOD mouse remains a pillar of autoimmune diabetes research for its usefulness as a preclinical model and because it provides access to invasive procedures as well as tissues that are rarely procured from patients or controls. The current article is focused on approaches to improve the NOD mouse by addressing reasons why immune therapies have failed to translate from mice to humans. We also propose new strategies for mixing and editing the NOD genome to improve the model in ways that will better advance our understanding of human diabetes. As proof of concept, we report that diabetes is completely suppressed in a knock-in NOD strain with a serine to aspartic acid substitution at position 57 in the MHC class II Aβ. This supports that similar non-aspartic acid substitutions at residue 57 of variants of the human class II HLA-DQβ homolog confer diabetes risk.

T Cell-Mediated Beta Cell Destruction: Autoimmunity and Alloimmunity in the Context of Type 1 Diabetes

Type 1 diabetes (T1D) results from destruction of pancreatic beta cells by T cells of the immune system. Despite improvements in insulin analogs and continuous blood glucose level monitoring, there is no cure for T1D, and some individuals develop life-threatening complications. Pancreas and islet transplantation have been attractive therapeutic approaches; however, transplants containing insulin-producing cells are vulnerable to both recurrent autoimmunity and conventional allograft rejection. Current immune suppression treatments subdue the immune system, but not without complications. Ideally a successful approach would target only the destructive immune cells and leave the remaining immune system intact to fight foreign pathogens. This review discusses the autoimmune diabetes disease process, diabetic complications that warrant a transplant, and alloimmunity. First, we describe the current understanding of autoimmune destruction of beta cells including the roles of CD4 and CD8 T cells and several possibilities for antigen-specific tolerance induction. Second, we outline diabetic complications necessitating beta cell replacement. Third, we discuss transplant recognition, potential sources for beta cell replacement, and tolerance-promoting therapies under development. We hypothesize that a better understanding of autoreactive T cell targets during disease pathogenesis and alloimmunity following transplant destruction could enhance attempts to re-establish tolerance to beta cells.

Longitudinal Frequencies of Blood Leukocyte Subpopulations Differ between NOD and NOR Mice but Do Not Predict Diabetes in NOD Mice

Immune phenotyping provides insight into disease pathogenesis and prognostic markers. Trajectories from age of 4 to 36 weeks were modeled for insulin autoantibodies and for leukocyte subpopulations in peripheral blood from female NOD (n = 58) and NOR (n = 22) mice. NOD mice had higher trajectories of insulin autoantibodies, CD4(+) and CD8(+) T lymphocytes, B lymphocytes, IgD(+)IgM(-) B lymphocytes, and NK cells and lower trajectories of CD4(+)CD25(+) T lymphocytes, IgM(+) B lymphocytes, granulocytes, and monocytes than NOR mice (all p < 0.001). Of these, only the increased IAA trajectory was observed in NOD mice that developed diabetes as compared to NOD mice that remained diabetes-free. Therefore, the profound differences in peripheral blood leukocyte proportions observed between the diabetes-prone NOD mice and the diabetes-resistant mice do not explain the variation in diabetes development within NOD mice and do not provide markers for diabetes prediction in this model.

Genetic architecture of early pre-inflammatory stage transcription signatures of autoimmune diabetes in the pancreatic lymph nodes of the NOD mouse reveals significant gene enrichment on chromosomes 6 and 7

Autoimmune diseases are characterized by the stimulation of an excessive immune response to self-tissues by inner and/or outer organism factors. Common characteristics in their etiology include a complex genetic predisposition and environmental triggers as well as the implication of the major histocompatibility (MHC) locus on human chromosome 6p21. A restraint number of non-MHC susceptibility genes, part of the genetic component of type 1 diabetes have been identified in human and in animal models, while the complete spectrum of genes involved remains unknown. We elaborate herein patterns of chromosomal organization of 162 genes differentially expressed in the pancreatic lymph nodes of Non-Obese Diabetic mice, carefully selected by early sub-phenotypic evaluation (presence or absence of insulin autoantibodies). Chromosomal assignment of these genes revealed a non-random distribution on five chromosomes (47%). Significant gene enrichment was observed in particular for two chromosomes, 6 and 7. While a subset of these genes coding for secreted proteins showed significant enrichment on both chromosomes, the overall pool of genes was significantly enriched on chromosome 7. The significance of this unexpected gene distribution on the mouse genome is discussed in the light of novel findings indicating that genes affecting common diseases map to recombination “hotspot” regions of mammalian genomes. The genetic architecture of transcripts differentially expressed in specific stages of autoimmune diabetes offers novel venues towards our understanding of patterns of inheritance potentially affecting the pathological disease mechanisms.

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Chromosomal organization of differentially expressed genes in early autoimmunity

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Non-random distribution of type 1 diabetes-related transcripts on the mouse genome

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High density of genetic polymorphisms on specific loci of chromosomes 6 and 7

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Correlation of mapping positions on chromosomes 6 and 7 with known T1D loci

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Our study offers candidate genes and loci drawn in the genomics of T1D initiation.

Autoimmunity and antibody affinity maturation are modulated by genetic variants on mouse chromosome 12

Autoimmune diseases result from a break in immune tolerance leading to an attack on self-antigens. Autoantibody levels serve as a predictive tool for the early diagnosis of many autoimmune diseases, including type 1 diabetes. We find that a genetic locus on mouse chromosome 12 influences the affinity maturation of antibodies as well as autoantibody production. Thus, we generated a NOD.H2(k) congenic strain bearing B10 alleles at the locus comprised within the D12Mit184 and D12Mit12 markers, which we named NOD.H2(k)-Chr12. We determined the biological relevance of the Chr12 locus on the autoimmune process using an antigen-specific TCR transgenic autoimmune mouse model. Specifically, the 3A9 TCR transgene, which recognizes a peptide from hen egg lysozyme (HEL) in the context of I-A(k), and the HEL transgene, which is expressed under the rat-insulin promoter (iHEL), were bred into the NOD.H2(k)-Chr12 congenic strain. In the resulting 3A9 TCR:iHEL NOD.H2(k)-Chr12 mice, we observed a significant decrease in diabetes incidence as well as a decrease in both the quantity and affinity of HEL-specific IgG autoantibodies relative to 3A9 TCR:iHEL NOD.H2(k) mice. Notably, the decrease in autoantibodies due to the Chr12 locus was not restricted to the TCR transgenic model, as it was also observed in the non-transgenic NOD.H2(k) setting. Of importance, antibody affinity maturation upon immunization and re-challenge was also impeded in NOD.H2(k)-Chr12 congenic mice relative to NOD.H2(k) mice. Together, these results demonstrate that a genetic variant(s) present within the Chr12 locus plays a global role in modulating antibody affinity maturation.

The mouse idd2 locus is linked to the proportion of immunoregulatory double-negative T cells, a trait associated with autoimmune diabetes resistance

Autoimmune diseases result from a break in immune tolerance. Various mechanisms of peripheral tolerance can protect against autoimmunity, including immunoregulatory CD4(-)CD8(-) double-negative (DN) T cells. Indeed, we have previously shown that diabetes-prone mouse strains exhibit a low proportion of DN T cells relative to that of diabetes-resistant mice, and that a single autologous transfer of DN T cells can impede autoimmune diabetes development, at least in the 3A9 TCR transgenic setting. In this study, we aim to understand the genetic basis for the difference in DN T cell proportion between diabetes-resistant and diabetes-prone mice. We thus perform an unbiased linkage analysis in 3A9 TCR F2 (NOD.H2(k) × B10.BR) mice and reveal that a locus on chromosome 9, which coincides with Idd2, is linked to the proportion of DN T cells in the lymph nodes. We generate two NOD.H2(k).B10-Chr9 congenic mouse strains and validate the role of this genetic interval in defining the proportion of DN T cells. Moreover, we find that the increased proportion of DN T cells in lymphoid organs is associated with a decrease in both diabetes incidence and serum IgG Ab levels. Together, the data suggest that Idd2 is linked to DN T cell proportion and that a physiological increase in DN T cell number may be sufficient to confer resistance to autoimmune diabetes. Altogether, these findings could help identify new candidate genes for the development of therapeutic avenues aimed at modulating DN T cell number for the prevention of autoimmune diseases.

The unique neonatal NK cells: a critical component required for neonatal autoimmune disease induction by maternal autoantibody

Human maternal autoantibodies can trigger autoimmune diseases such as congenital heart block (CHB) in the progeny of women with lupus or Sjogren’s disease. The pathogenic effect of early autoantibody (autoAb) exposure has been investigated in a murine neonatal autoimmune ovarian disease (nAOD) model triggered by a unique ZP3 antibody. Although immune complexes (IC) are formed in adult and neonatal ovaries, ZP3 antibody triggers severe nAOD only in <7-day-old neonatal mice. Propensity to nAOD is due to the uniquely hyper-responsive neonatal natural killer (NK) cells that lack the inhibitory Ly49C/I receptors. In nAOD, the neonatal NK cells directly mediate ovarian inflammation and oocyte depletion while simultaneously promoting de novo pathogenic ovarian-specific T cell responses. Resistance to nAOD in older mice results from the emergence of the Ly49C/I⁺ NK cells that regulate effector NK cells and from CD25⁺ regulatory T cell control. In preliminary studies, FcγRIII⁺ NK cells as well as the ovarian resident FcγRIII⁺ macrophages and/or dendritic cells were found to be as indispensable players. Activated by ovarian IC, they migrate to lymphoid organs where NK cell priming occurs. Remarkably, the findings in nAOD are very similar to those reported for neonatal responses to a retrovirus and its cognate antibody that lead to long-lasting immunity. Studies on nAOD therefore provide insights into maternal autoAb-mediated neonatal autoimmunity, including CHB, while simultaneously uncovering new properties of the neonatal innate and adaptive responses, lethality of premature infant infection, and novel neonatal antiviral vaccine design.

Antigen presentation in the autoimmune diabetes of the NOD mouse

This paper reviews the presentation of peptides by major histocompatibility complex (MHC) class II molecules in the autoimmune diabetes of the nonobese diabetic (NOD) mouse. Islets of Langerhans contain antigen-presenting cells that capture the proteins and peptides of the beta cells' secretory granules. Peptides bound to I-A(g7), the unique MHC class II molecule of NOD mice, are presented in islets and in pancreatic lymph nodes. The various beta cell-derived peptides interact with selected CD4 T cells to cause inflammation and beta cell demise. Many autoreactive T cells are found in NOD mice, but not all have a major role in the initiation of the autoimmune process. I emphasize here the evidence pointing to insulin autoreactivity as a seminal component in the diabetogenic process.

Transmaternal bisphenol A exposure accelerates diabetes type 1 development in NOD mice

Diabetes mellitus type 1 is an autoimmune disease with a genetic predisposition that is triggered by environmental factors during early life. Epidemiological studies show that bisphenol A (BPA), an endocrine disruptor, has been detected in about 90% of all analyzed human urine samples. In this study, BPA was found to increase the severity of insulitis and the incidence of diabetes in female non obese diabetic (NOD) mice offspring after transmaternal exposure through the dams' drinking water (0, 0.1, 1, and 10mg/l). Both the severity of insulitis in the pancreatic islets at 11 weeks of age and the diabetes prevalence at 20 weeks were significantly increased for female offspring in the highest exposure group compared to the control group. Increased numbers of apoptotic cells, a reduction in tissue resident macrophages and an increase in regulatory T cells were observed in islets prior to insulitis development in transmaternally exposed offspring. The detectable apoptotic cells were identified as mostly glucagon producing alpha-cells but also tissue resident macrophages and beta-cells. In the local (pancreatic) lymph node neither regulatory T cell nor NKT cell populations were affected by maternal BPA exposure. Maternal BPA exposure may have induced systemic immune changes in offspring, as evidenced by alterations in LPS- and ConA-induced cytokine secretion in splenocytes. In conclusion, transmaternal BPA exposure, in utero and through lactation, accelerated the spontaneous diabetes development in NOD mice. This acceleration appeared to be related to early life modulatory effects on the immune system, resulting in adverse effects later in life.

Long-term bisphenol A exposure accelerates insulitis development in diabetes-prone NOD mice

Exposure to the endocrine disruptor (ED) bisphenol A (BPA) used in polycarbonate plastic and epoxy resins appears ubiquitous since BPA can be found in over 90% of analyzed urine samples from all age groups. There is a parallel occurrence of increased prevalence in type 1 diabetes mellitus (T1DM) and an increased exposure to EDs the last decades. T1DM is caused by insulin deficiency due to autoimmune destruction of insulin producing pancreatic beta cells and has been suggested to be induced by various environmental factors acting together with a genetic predisposition. The objective of the present study was to investigate the effect of BPA (0, 1 and 100 mg/l BPA in the drinking water) on T1DM development in nonobese diabetic (NOD) mice, spontaneously developing T1DM. Histological evaluation of pancreas from 12-weeks-old female mice revealed significantly increased insulitis in mice exposed to 1 mg/l BPA, while the insulitis was less severe at the higher BPA exposure. Serum glucose levels in the 1 mg/ml BPA group tended to be hyperglycaemic, also indicating an accelerated onset of T1DM. The high BPA exposure seemed to counteract the diabetes development in females and also in male NOD mice for both BPA concentrations. Prior to insulitis, both BPA concentrations resulted in increased apoptosis and reduced numbers of tissue resident macrophages in pancreatic islets. In conclusion, long-term BPA exposure at a dose three times higher than the tolerable daily intake of 50 µg/kg, appeared to accelerate spontaneous insulitis and diabetes development in NOD mice.

Bioluminescence imaging reveals dynamics of beta cell loss in the non-obese diabetic (NOD) mouse model

We generated a mouse model (MIP-Luc-VU-NOD) that enables non-invasive bioluminescence imaging (BLI) of beta cell loss during the progression of autoimmune diabetes and determined the relationship between BLI and disease progression. MIP-Luc-VU-NOD mice displayed insulitis and a decline in bioluminescence with age which correlated with beta cell mass, plasma insulin, and pancreatic insulin content. Bioluminescence declined gradually in female MIP-Luc-VU-NOD mice, reaching less than 50% of the initial BLI at 10 weeks of age, whereas hyperglycemia did not ensue until mice were at least 16 weeks old. Mice that did not become diabetic maintained insulin secretion and had less of a decline in bioluminescence than mice that became diabetic. Bioluminescence measurements predicted a decline in beta cell mass prior to the onset of hyperglycemia and tracked beta cell loss. This model should be useful for investigating the fundamental processes underlying autoimmune diabetes and developing new therapies targeting beta cell protection and regeneration.

Nearby Construction Impedes the Progression to Overt Autoimmune Diabetes in NOD Mice

Construction nearby animal houses has sporadically been reported to affect various aspects of animal health. Most of the reports have focussed on the impact on stress hormone levels and the hypersensitivity of animals relative to humans. There has also been an anecdotal report on the impact of construction on autoimmune diabetes in NOD mice. Here, we describe that nearby construction significantly impedes the progression to overt diabetes in female NOD mice offspring. We demonstrate that this was not due to a genetic drift or to particularities associated with our specific mouse colony. Interestingly, although the glycemia levels remained low in mice born from mothers subject to construction stress during gestation, we detected an active autoimmune reaction towards pancreatic islet cells, as measured by both the degree of insulitis and the presence of insulin autoantibody levels in the serum. These results suggest that the external stress imposed during embryonic development does not prevent but significantly delays the autoimmune process. Together, our findings emphasize the impact of surrounding factors during in vivo studies and are in agreement with the hypothesis that both environmental and genetic cues contribute to autoimmune diabetes development.

Investigation of secreted protein transcripts as early biomarkers for type 1 diabetes in the mouse model

Type 1 diabetes (T1D) represents a serious health burden in the world, complicated by the fact that disease onset can be preceded by a long time period without evident clinical signs. It would be then of critical importance to detect the disease in its early stages. In this direction, we seek here to identify early preinflammatory markers for autoimmune diabetes, mining our previously reported transcriptome data relevant to distinct early sub-phenotypes in the NOD mouse, associated with early insulin autoantibodies (E-IAA). More specifically we focus on secreted or transmembrane protein transcripts, identifying in this category 71 differentially expressed transcripts which are regulated at the early preinflammatory stages of T1D in the pancreatic lymph nodes (PLN). Following the expression patterns of these 71 transcripts, correspondence analysis (a multivariate analysis method) reveals a clear-cut segregation of the individual samples according to the early subphenotype used. Thus the 71 transcripts coding for secreted proteins constitute a candidate-set of predictive biomarkers for the development of autoimmune damage of the β cells of the pancreas. The majority of these genes have human orthologs and accordingly they represent potential candidate biomarkers for the human disease. In addition, for predictive purposes, the analysis reveals the possibility to reduce significantly the size of the candidate-set in practice, with various genes displaying identical expression profiles.

Early determinants of type 1 diabetes: experience from the BABYDIAB and BABYDIET studies

Type 1 diabetes is an immune-mediated disorder that results from progressive destruction of the islet β cells. A genetic susceptibility for the development of islet autoimmunity and type 1 diabetes is well documented, and an environmental influence is assumed. Prospective studies from birth have shown that islet autoimmunity occurs very early in life, which implies that fetal or postnatal environmental factors may program the development of islet autoimmunity. In this overview, results from the BABYDIAB study, a prospective study from birth on the natural history of type 1 diabetes, and the BABYDIET study, a dietary intervention study, are discussed with a focus on the role of a diabetes environment in utero and the role of early gluten exposure on islet autoimmunity risk in children.

Antibodies against insulin measured by electrochemiluminescence predicts insulitis severity and disease onset in non-obese diabetic mice and can distinguish human type 1 diabetes status

BACKGROUND

The detection of insulin autoantibodies (IAA) aids in the prediction of autoimmune diabetes development. However, the long-standing, gold standard 125I-insulin radiobinding assay (RBA) has low reproducibility between laboratories, long sample processing times and requires the use of newly synthesized radiolabeled insulin for each set of assays. Therefore, a rapid, non-radioactive, and reproducible assay is highly desirable.

METHODS

We have developed electrochemiluminescence (ECL)-based assays that fulfill these criteria in the measurement of IAA and anti-insulin antibodies (IA) in non-obese diabetic (NOD) mice and in type 1 diabetic individuals, respectively. Using the murine IAA ECL assay, we examined the correlation between IAA, histopathological insulitis, and blood glucose in a cohort of female NOD mice from 4 up to 36 weeks of age. We developed a human IA ECL assay that we compared to conventional RBA and validated using samples from 34 diabetic and 59 non-diabetic individuals in three independent laboratories.

RESULTS

Our ECL assays were rapid and sensitive with a broad dynamic range and low background. In the NOD mouse model, IAA levels measured by ECL were positively correlated with insulitis severity, and the values measured at 8-10 weeks of age were predictive of diabetes onset. Using human serum and plasma samples, our IA ECL assay yielded reproducible and accurate results with an average sensitivity of 84% at 95% specificity with no statistically significant difference between laboratories.

CONCLUSIONS

These novel, non-radioactive ECL-based assays should facilitate reliable and fast detection of antibodies to insulin and its precursors sera and plasma in a standardized manner between laboratories in both research and clinical settings. Our next step is to evaluate the human IA assay in the detection of IAA in prediabetic subjects or those at risk of type 1 diabetes and to develop similar assays for other autoantibodies that together are predictive for the diagnosis of this common disorder, in order to improve prediction and facilitate future therapeutic trials.

Loss of intra-islet CD20 expression may complicate efficacy of B-cell-directed type 1 diabetes therapies

OBJECTIVE

Consistent with studies in NOD mice, early clinical trials addressing whether depletion of B cells by the Rituximab CD20-specific antibody provides an effective means for type 1 diabetes reversal have produced promising results. However, to improve therapeutic efficacy, additional B-cell-depleting agents, as well as attempts seeking diabetes prevention, are being considered.

RESEARCH DESIGN AND METHODS

Autoantibodies, including those against insulin (IAAs), are used to identify at-risk subjects for inclusion in diabetes prevention trials. Therefore, we tested the ability of anti-CD20 to prevent diabetes in NOD mice when administered either before or after IAA onset.

RESULTS

The murine CD20-specific 18B12 antibody that like Rituximab, depletes the follicular (FO) but not marginal zone subset of B cells, efficiently inhibited diabetes development in NOD mice in a likely regulatory T-cell-dependent manner only when treatment was initiated before IAA detection. One implication of these results is that the FO subset of B cells preferentially contributes to early diabetes initiation events. However, most important, the inefficient ability of anti-CD20 treatment to exert late-stage diabetes prevention was found to be attributable to downregulation of CD20 expression upon B cell entry into pancreatic islets.

CONCLUSIONS

These findings provide important guidance for designing strategies targeting B cells as a potential means of diabetes intervention.

Beyond the hormone: insulin as an autoimmune target in type 1 diabetes

Insulin is not only the hormone produced by pancreatic β-cells but also a key target antigen of the autoimmune islet destruction leading to type 1 diabetes. Despite cultural biases between the fields of endocrinology and immunology, these two facets should not be regarded separately, but rather harmonized in a unifying picture of diabetes pathogenesis. There is increasing evidence suggesting that metabolic factors (β-cell dysfunction, insulin resistance) and immunological components (inflammation and β-cell-directed adaptive immune responses) may synergize toward islet destruction, with insulin standing at the crossroad of these pathways. This concept further calls for a revision of the classical dichotomy between type 1 and type 2 diabetes because metabolic and immune mechanisms may both contribute to different extents to the development of different forms of diabetes. After providing a background on the mechanisms of β-cell autoimmunity, we will explain the role of insulin and its precursors as target antigens expressed not only by β-cells but also in the thymus. Available knowledge on the autoimmune antibody and T-cell responses against insulin will be summarized. A unifying scheme will be proposed to show how different aspects of insulin biology may lead to β-cell destruction and may be therapeutically exploited. We will argue about possible reasons why insulin remains the mainstay of metabolic control in type 1 diabetes but has so far failed to prevent or halt β-cell autoimmunity as an immune modulatory reagent.

Progressive erosion of β-cell function precedes the onset of hyperglycemia in the NOD mouse model of type 1 diabetes

OBJECTIVE

A progressive decline in insulin responses to glucose was noted in individuals before the onset of type 1 diabetes. We determined whether such abnormalities occurred in prediabetic NOD mice-the prototypic model for human type 1 diabetes.

RESEARCH DESIGN AND METHODS

Morning blood glucose was measured every other day in a cohort of NOD females. Glucose tolerance and insulin secretion were measured longitudinally by intraperitoneal glucose tolerance tests in NOD/ShiLtJ and BALB/cJ mice 6 to 14 weeks of age. Arginine-stimulated insulin secretion and insulin sensitivity were assessed during intraperitoneal arginine or intraperitoneal insulin tolerance tests.

RESULTS

During prediabetes, NOD females displayed a progressive increase in glucose levels followed by an acute onset of hyperglycemia. First-phase insulin responses (FPIRs) during the intraperitoneal glucose tolerance test (IPGTT) declined before loss of glucose tolerance in NOD. The failure of FPIR could be detected, with a decline in peak insulin secretion during IPGTT. Arginine-stimulated insulin secretion remained unchanged during the study period. The decline in insulin secretion in NOD mice could not be explained by changes in insulin sensitivity.

CONCLUSIONS

There was an impressive decline in FPIR before changes in glucose tolerance, suggesting that impairment of FPIR is an early in vivo marker of progressive β-cell failure in NOD mice and human type 1 diabetes. We portend that these phenotypes in NOD mice follow a similar pattern to those seen in humans with type 1 diabetes and validate, in a novel way, the importance of this animal model for studies of this disease.

Anti-islet autoantibodies trigger autoimmune diabetes in the presence of an increased frequency of islet-reactive CD4 T cells

OBJECTIVE

To define cellular mechanisms by which B cells promote type 1 diabetes.

RESEARCH DESIGN AND METHODS

The study measured islet-specific CD4 T cell regulation in T-cell receptor transgenic mice with elevated frequencies of CD4 T cells recognizing hen egg lysozyme (HEL) autoantigen expressed in islet β-cells and thymic epithelium under control of the insulin-gene promoter. The effects of a mutation in Roquin that dysregulates T follicular helper (Tfh) cells to promote B-cell activation and anti-islet autoantibodies were studied, as were the effects of HEL antigen-presenting B cells and passively transferred or maternally transmitted anti-islet HEL antibodies.

RESULTS

Mouse anti-islet IgG antibodies-either formed as a consequence of excessive Tfh activity, maternally transmitted, or passively transferred-caused a breakdown of tolerance in islet-reactive CD4(+) cells and fast progression to diabetes. Progression to diabetes was ameliorated in the absence of B cells or when the B cells could not secrete islet-specific IgG. Anti-islet antibodies increased the survival of proliferating islet-reactive CD4(+) T cells. FcγR blockade delayed and reduced the incidence of autoimmune diabetes.

CONCLUSIONS

B cells can promote type 1 diabetes by secreting anti-islet autoantibodies that act in an FcγR-mediated manner to enhance the expansion of islet-reactive CD4 T cells and cooperate with inherited defects in thymic and peripheral CD4 T-cell tolerance. Cooperation between inherited variants affecting CD4 T-cell tolerance and anti-islet autoantibodies should be examined in epidemiological studies and in studies examining the efficacy of B-cell depletion.

Metabolic imprinting, programming and epigenetics – a review of present priorities and future opportunities

Metabolic programming and metabolic imprinting describe early life events, which impact upon on later physiological outcomes. Despite the increasing numbers of papers and studies, the distinction between metabolic programming and metabolic imprinting remains confusing. The former can be defined as a dynamic process whose effects are dependent upon a critical window(s) while the latter can be more strictly associated with imprinting at the genomic level. The clinical end points associated with these phenomena can sometimes be mechanistically explicable in terms of gene expression mediated by epigenetics. The predictivity of outcomes depends on determining if there is causality or association in the context of both early dietary exposure and future health parameters. The use of biomarkers is a key aspect of determining the predictability of later outcome, and the strengths of particular types of biomarkers need to be determined. It has become clear that several important health endpoints are impacted upon by metabolic programming/imprinting. These include the link between perinatal nutrition, nutritional epigenetics and programming at an early developmental stage and its link to a range of future health risks such as CVD and diabetes. In some cases, the evidence base remains patchy and associative, while in others, a more direct causality between early nutrition and later health is clear. In addition, it is also essential to acknowledge the communication to consumers, industry, health care providers, policy-making bodies as well as to the scientific community. In this way, both programming and, eventually, reprogramming can become effective tools to improve health through dietary intervention at specific developmental points.

Early over expression of messenger RNA for multiple genes, including insulin, in the Pancreatic Lymph Nodes of NOD mice is associated with Islet Autoimmunity

BACKGROUND

Autoimmune diabetes (T1D) onset is preceded by a long inflammatory process directed against the insulin-secreting beta cells of the pancreas. Deciphering the early autoimmune mechanisms represents a challenge due to the absence of clinical signs at early disease stages. The aim of this study was to identify genes implicated in the early steps of the autoimmune process, prior to inflammation, in T1D. We have previously established that insulin autoantibodies (E-IAA) predict early diabetes onset delineating an early phenotypic check point (window 1) in disease pathogenesis. We used this sub-phenotype and applied differential gene expression analysis in the pancreatic lymph nodes (PLN) of 5 weeks old Non Obese Diabetic (NOD) mice differing solely upon the presence or absence of E-IAA. Analysis of gene expression profiles has the potential to provide a global understanding of the disease and to generate novel hypothesis concerning the initiation of the autoimmune process.

METHODS

Animals have been screened weekly for the presence of E-IAA between 3 and 5 weeks of age. E-IAA positive or negative NOD mice at least twice were selected and RNAs isolated from the PLN were used for microarray analysis. Comparison of transcriptional profiles between positive and negative animals and functional annotations of the resulting differentially expressed genes, using software together with manual literature data mining, have been performed.

RESULTS

The expression of 165 genes was modulated between E-IAA positive and negative PLN. In particular, genes coding for insulin and for proteins known to be implicated in tissue remodelling and Th1 immunity have been found to be highly differentially expressed. Forty one genes showed over 5 fold differences between the two sets of samples and 30 code for extracellular proteins. This class of proteins represents potential diagnostic markers and drug targets for T1D.

CONCLUSION

Our data strongly suggest that the immune related mechanisms taking place at this early age in the PLN, correlate with homeostatic changes influencing tissue integrity of the adjacent pancreatic tissue. Functional analysis of the identified genes suggested that similar mechanisms might be operating during pre-inflammatory processes deployed in tissues i) hosting parasitic microorganisms and ii) experiencing unrestricted invasion by tumour cells.

The postnatal maternal environment influences diabetes development in nonobese diabetic mice

When nonobese-diabetic (NOD) mouse embryos were implanted into pseudopregnant mothers of a nonautoimmune mouse strain, the progeny had a reduced type 1 diabetes (T1D) incidence, suggesting that transmission of maternal autoantibodies is important for T1D development. Whether eliminating islet autoantibody transmission in utero, or postnatally (through milk), prevented T1D is unknown. Herein, we show that fostering newborn NOD mice on B-cell deficient NOD.Igmu-/- dams does not prevent T1D, demonstrating that postnatally transmitted islet autoantibodies are not required for disease pathogenesis. Additionally, NOD.Igmu-/- mice reared on NOD dams did not develop T1D, indicating that autoantibody transmission to B-cell deficient NOD neonates is insufficient to trigger T1D. Interestingly, newborn NOD mice that were reared by ICR (but not NOD or C57BL/6) dams had reduced T1D incidence, although not as reduced as that reported after embryo transfer to ICR mice, suggesting that both prenatal and postnatal factors contribute to the observed reduction in T1D incidence. Thus, NOD mice have different risks for developing T1D depending on the strain of their foster mother, and both prenatal and postnatal maternal factors, other than islet autoantibodies, influence their T1D incidence. The results may be relevant for understanding the increasing incidence of T1D and designing interventions.

Rational development of antigen-specific therapies for type 1 diabetes

Administration of autoantigens, especially via the mucosal route, can induce tolerance under certain circumstances. In autoimmune diabetes, mucosal vaccination with autoantigens was frequently effective in restoring tolerance in mice but has not yet succeeded in humans. Furthermore, in some instances, autoimmunity can be precipitated upon autoantigen administration. We will here briefly discuss the underlying reasons and delineate which efforts should be made in the future to rationally translate antigen-specific immunotherapy, for example, by establishing better assays to reduce the risk for possible adverse events in humans.

B cells move to centre stage: novel opportunities for autoimmune disease treatment

The B-cell arm of the immune system has long been appreciated for its crucial role in pathogen resistance, but in the study of many autoimmune diseases, T cells have dominated the limelight for decades. However, the development of the B-cell-depleting antibody rituximab as a lymphoma therapy has provided a tool to probe the contribution made by B cells in several immune disorders. Recently, the success of B-cell depletion with rituximab in the treatment of rheumatoid arthritis has stimulated investigation of its effects in several other immune disorders, and considerable interest in the potential of drugs that can modulate B-cell function for the treatment of such diseases in general. This article discusses the role of B cells in a range of autoimmune disorders, including rheumatoid arthritis and systemic lupus erythematosus, and analyses approaches to therapeutic B-cell manipulation.

Transgenic insulin (B:9-23) T-cell receptor mice develop autoimmune diabetes dependent upon RAG genotype, H-2g7 homozygosity, and insulin 2 gene knockout

A series of recent studies in humans and the NOD mouse model have highlighted the central role that autoimmunity directed against insulin, in particular the insulin B chain 9-23 peptide, may play in the pathogenesis of type 1 diabetes. Both pathogenic and protective T-cell clones recognizing the B:9-23 peptide have been produced. This report describes the successful creation of BDC12-4.1 T-cell receptor (TCR) transgenic mice with spontaneous insulitis in F1 mice (FVB x NOD) and spontaneous diabetes in NOD.RAG(-/-) (backcross 1 generation). Disease progression is heterogeneous and is modified by a series of genetic factors including heterozygosity (H-2(g7)/H-2(q)) versus homozygosity for H-2(g7), the presence of additional T-/B-cell receptor-rearranged genes (RAG(+) versus RAG(-/-)), and the insulin 2 gene knockout (the insulin gene expressed in the NOD thymus). Despite lymphopenia, 40% of H-2(g7/g7) BDC12-4.1 TCR(+) RAG(-/-) Ins2(-/-) mice are diabetic by 10 weeks of age. As few as 13,500 transgenic T-cells from a diabetic TCR(+) RAG(-/-) mouse can transfer diabetes to an NOD.scid mouse. The current study demonstrates that the BDC12-4.1 TCR is sufficient to cause diabetes at NOD backcross 1, bypassing polygenic inhibition of insulitis and diabetogenesis.

Natural history of type 1 diabetes

The natural history of autoimmune type 1 diabetes in children is associated with the appearance of islet autoantibodies early in life, which is influenced by genetic and environmental factors. Once islet autoantibodies have developed, the progression to diabetes in antibody-positive individuals is determined by the age of antibody appearance and by the magnitude of the autoimmunity, in turn related to the age of the subject. Characteristics that describe the magnitude of the autoimmunity can stage progression to type 1 diabetes in islet autoantibody-positive subjects regardless of genetic background or age.

Immunopathogenic role of TH1 cells in autoimmune diabetes: Evidence from a T1 and T2 doubly transgenic non-obese diabetic mouse model

To improve the feasibility of in vivo monitoring of autoreactive T cells in the diabetogenic process, we generated T1 and T2 doubly transgenic non-obese diabetic (NOD) mice in which transgenic human CD90 (hCD90) is simultaneously expressed on IFN-gamma-producing cells or murine CD90.1 (mCD90.1) is expressed on IL-4-producing cells. These transgenic NOD mice develop diabetes with the same kinetics and incidence as wild type NOD mice, permitting the physiological characterization of CD4(+)hCD90(+) cells, which represent T(H)1 cells in lymphoid organs and at the site of insulitis. CD4(+)hCD90(+) cells had a higher capacity to secret IFN-gamma than CD4(+)hCD90(-) cells in an autoantigen-specific manner. Transgenic mice treated with GAD65 plasmid were protected from autoimmune diabetes, and had a lower number of CD4(+)hCD90(+) cells, confirming the pathogenic role of CD4(+)hCD90(+) cells in autoimmune diabetes. To further investigate the effect of IL-12 on the development of T(H)1 cells in autoimmune diabetes, we crossed these doubly transgenic mice to IL-12p35-deficient NOD mice. Despite severe disturbance of diabetes in p35(-/-) mice, the frequency of T(H)1 cells in these mice was slightly lower than in wild type mice. These data support the pathological role of IL-12 in autoimmune diabetes and suggest the existence an IL-12-independent pathway of T(H)1 development.

"Agouti NOD": identification of a CBA-derived Idd locus on Chromosome 7 and its use for chimera production with NOD embryonic stem cells

Penetrance of the complex of genes predisposing the nonobese diabetic (NOD) mouse to autoimmune diabetes is affected by the maternal environment. NOD.CBALs-Tyr(+)/Lt is an agouti-pigmented Chromosome 7 congenic stock of NOD/Lt mice produced as a resource for embryo transfer experiments to provide the necessary maternal factors and allow the easy identification of NOD (albino) embryo donor phenotype. CBcNO6/Lt, a recombinant congenic agouti stock already containing approximately 50% NOD genome, was used as the donor source of a wild-type CBA tyrosinase allele. When the incidence of diabetes was assessed after nine generations of backcrossing and one generation of sib-sib mating, significant reduction in diabetes development was observed. No difference in diabetes development was observed in Tyr/Tyr(c) heterozygotes, showing that protection was recessive. Analysis of diabetes progression in another NOD stock congenic for C57BL/6 alleles on Chromosome 7 linked to the glucose phosphate isomerase (Gpi1(b)) locus provided no protection, indicating that the diabetes resistance (Idd) gene was distal to 34 cM (D7Mit346). Approximately 5 cM of the distal congenic region overlaps a region from C57L previously associated with protection when homozygous. The delayed onset and reduced frequency of diabetes in the NOD.CBALs-Tyr(+)/Lt stock is an advantage when females of this stock are used as surrogate mothers in studies involving hysterectomy or embryo transfers. Indeed, a newly developed NOD embryonic stem (ES) cell line injected into NOD.CBALs- Tyr(+)/Lt blastocysts produced approximately 50% live-born mice, of which approximately 11% were chimeric. Presumably because of high genomic instability, no germline transmission was observed.

Functional genomics in early autoimmunity

The molecular mechanisms initiating the autoimmune process in type 1 diabetes mellitus (T1DM) remain unknown, and studies aiming to address this question have been compromised by the difficulty of predicting the disease at an early age both in humans and in animal models. An additional hindrance in selecting individuals at an early age has been the complex genetic inheritance of autoimmune diabetes, implicating not only several genes but also environmental factors. We have previously demonstrated the predictive value of insulin autoantibodies (IAAs) at an early age, between three to five weeks in the NOD mouse. Animals positive for early appearance of IAAs (E-IAAs) develop autoimmune diabetes earlier. We showed a correlation between the presence of IAAs in the mothers during pregnancy, E-IAAs in the litters, and the early appearance of T1DM. NOD mice, E-IAA-positive, within litters from IAA-positive mothers during pregnancy, develop diabetes earlier and at a much greater rate than animals that are IAA-negative and from IAA-negative mothers. The molecular mechanisms responsible for this early autoimmune subphenotype were addressed by a global approach to differential gene expression analysis in the pancreatic lymph nodes (PaLNs). Although the data analysis is currently in progress, gene expression signatures were observed that are characteristic for PaLNs with regard to the presence or absence of IAAs. Overall, these data are consistent with the hypothesis of an early environmental influence from the autoimmune maternal environment on the genetic predisposition of the offspring, characterized by specific gene signatures leading to autoimmune disease.

The autoimmune contrivance: genetics in the mouse model

Autoimmunity and inheritance of complex characters behold an explosive interest in biology over the last 15 years. Research in the genetics of autoimmunity has been impelled by the isolation of genetic markers allowing tracing of heredity. The annotation and sequencing of the human and mouse genomes provide with the potential for further advancements, through the development of new technologies. This review aims to summarize advances made in the autoimmunity field, centered in type 1 diabetes in the NOD mouse model. It also aims to demonstrate that animal models, albeit some phenotypic and genetic dissimilarities with the human diseases, still remain the best way to move towards an understanding of the molecular mechanisms involved in autoimmunity. Assessing the current state of research in this field together with the increasing potential of novel biotechnology advancements, new insights to disease pathogenesis and discovery of molecular targets for intervention strategies are anticipated in the coming years.