The NOD mouse: a model of immune dysregulation

Aire mediates tolerance to insulin through thymic trimming of high-affinity T cell clones

Insulin is a central autoantigen in the pathogenesis of T1D, and thymic epithelial cell expression of insulin under the control of the Autoimmune Regulator (Aire) is thought to be a key component of maintaining tolerance to insulin. In spite of this general working model, direct detection of this thymic selection on insulin-specific T cells has been somewhat elusive. Here, we used a combination of highly sensitive T cell receptor transgenic models for detecting thymic selection and sorting and sequencing of Insulin-specific CD4+ T cells from Aire-deficient mice as a strategy to further define their selection. This analysis revealed a number of unique t cell receptor (TCR) clones in Aire-deficient hosts with high affinity for insulin/major histocompatibility complex (MHC) ligands. We then modeled the thymic selection of one of these clones in Aire-deficient versus wild-type hosts and found that this model clone could escape thymic negative selection in the absence of thymic Aire. Together, these results suggest that thymic expression of insulin plays a key role in trimming and removing high-affinity insulin-specific T cells from the repertoire to help promote tolerance.

Autoimmune CD8+ T cells in type 1 diabetes: from single-cell RNA sequencing to T-cell receptor redirection

Type 1 diabetes (T1D) is an organ-specific autoimmune disease caused by pancreatic β cell destruction and mediated primarily by autoreactive CD8+ T cells. It has been shown that only a small number of stem cell-like β cell-specific CD8+ T cells are needed to convert normal mice into T1D mice; thus, it is likely that T1D can be cured or significantly improved by modulating or altering self-reactive CD8+ T cells. However, stem cell-type, effector and exhausted CD8+ T cells play intricate and important roles in T1D. The highly diverse T-cell receptors (TCRs) also make precise and stable targeted therapy more difficult. Therefore, this review will investigate the mechanisms of autoimmune CD8+ T cells and TCRs in T1D, as well as the related single-cell RNA sequencing (ScRNA-Seq), CRISPR/Cas9, chimeric antigen receptor T-cell (CAR-T) and T-cell receptor-gene engineered T cells (TCR-T), for a detailed and clear overview. This review highlights that targeting CD8+ T cells and their TCRs may be a potential strategy for predicting or treating T1D.

Network approach reveals preferential T-cell and macrophage association with α-linked β-cells in early stage of insulitis in NOD mice

One of the challenges in studying islet inflammation - insulitis - is that it is a transient phenomenon. Traditional reporting of the insulitis progression is based on cumulative, donor-averaged values of leucocyte density in the vicinity of pancreatic islets, that hinders intra- and inter-islet heterogeneity of disease progression. Here, we aimed to understand why insulitis is non-uniform, often with peri-insulitis lesions formed on one side of an islet. To achieve this, we demonstrated applicability of network theory in detangling intra-islet multi-cellular interactions during insulitis. Specifically, we asked the question "what is unique about regions of the islet which interact with immune cells first". This study utilized the non-obese diabetic mouse model of type one diabetes and examined the interplay among α-, β-, T-cells, myeloid cells, and macrophages in pancreatic islets during the progression of insulitis. Disease evolution was tracked based on T/β cell ratio in individual islets. In the early stage, we found that immune cells are preferentially interacting with α-cell-rich regions of an islet. At the islet periphery α-linked β-cells were found to be targeted significantly more compared to those without α-cell neighbors. Additionally, network analysis revealed increased T-myeloid, and T-macrophage interactions with all β-cells.

Refined protocol for newly onset identification in non-obese diabetic mice: an animal-friendly, cost-effective, and efficient alternative

BACKGROUND

Therapeutic interventions for diabetes are most effective when administered in the newly onset phase, yet determining the exact onset moment can be elusive in practice. Spontaneous autoimmune diabetes among NOD mice appears randomly between 12 and 32 weeks of age with an incidence range from 60 to 90%. Furthermore, the disease often progresses rapidly to severe diabetes within days, resulting in a very short window of newly onset phase, that poses significant challenge in early diagnosis. Conventionally, extensive blood glucose (BG) testing is typically required on large cohorts throughout several months to conduct prospective survey. We incorporated ultrasensitive urine glucose (UG) testing into an ordinary BG survey process, initially aiming to elucidate the lag period required for excessive glucose leaking from blood to urine during diabetes progression in the mouse model.

RESULTS

The observations unexpectedly revealed that small amounts of glucose detected in the urine often coincide with, sometimes even a couple days prior than elevated BG is diagnosed. Accordingly, we conducted the UG-based survey protocol in another cohort that was validated to accurately identified every individual near onset, who could then be confirmed by following few BG tests to fulfill the consecutive BG + criteria. This approach required fewer than 95 BG tests, compared to over 700 tests with traditional BG survey, to diagnose all the 37-38 diabetic mice out of total 60. The average BG level at diagnosis was slightly below 350 mg/dl, lower than the approximately 400 mg/dl observed with conventional BG monitoring.

CONCLUSIONS

We demonstrated a near perfect correlation between BG + and ultrasensitive UG + results in prospective survey with no lag period detected under twice weekly of testing frequency. This led to the refined protocol based on surveying with noninvasive UG testing, allowing for the early identification of newly onset diabetic mice with only a few BG tests required per mouse. This protocol significantly reduces the need for extensive blood sampling, lancet usage, labor, and animal distress, aligning with the 3Rs principle. It presents a convenient, accurate, and animal-friendly alternative for early diabetes diagnosis, facilitating research on diagnosis, pathogenesis, prevention, and treatment.

Tipping the balance in autoimmunity: are regulatory t cells the cause, the cure, or both?

Regulatory T cells (Tregs) are a specialized subgroup of T-cell lymphocytes that is crucial for maintaining immune homeostasis and preventing excessive immune responses. Depending on their differentiation route, Tregs can be subdivided into thymically derived Tregs (tTregs) and peripherally induced Tregs (pTregs), which originate from conventional T cells after extrathymic differentiation at peripheral sites. Although the regulatory attributes of tTregs and pTregs partially overlap, their modes of action, protein expression profiles, and functional stability exhibit specific characteristics unique to each subset. Over the last few years, our knowledge of Treg differentiation, maturation, plasticity, and correlations between their phenotypes and functions has increased. Genetic and functional studies in patients with numeric and functional Treg deficiencies have contributed to our mechanistic understanding of immune dysregulation and autoimmune pathologies. This review provides an overview of our current knowledge of Treg biology, discusses monogenetic Treg pathologies and explores the role of Tregs in various other autoimmune disorders. Additionally, we discuss novel approaches that explore Tregs as targets or agents of innovative treatment options.

The N-Methyl-D-Aspartate Receptor Antagonist Dextromethorphan Improves Glucose Homeostasis and Preserves Pancreatic Islets in NOD Mice

For treatment of type 1 diabetes mellitus, a combination of immune-based interventions and medication to promote beta-cell survival and proliferation has been proposed. Dextromethorphan (DXM) is an N-methyl-D-aspartate receptor antagonist with a good safety profile, and to date, preclinical and clinical evidence for blood glucose-lowering and islet-cell-protective effects of DXM have only been provided for animals and individuals with type 2 diabetes mellitus. Here, we assessed the potential anti-diabetic effects of DXM in the non-obese diabetic mouse model of type 1 diabetes. More specifically, we showed that DXM treatment led to five-fold higher numbers of pancreatic islets and more than two-fold larger alpha- and beta-cell areas compared to untreated mice. Further, DXM treatment improved glucose homeostasis and reduced diabetes incidence by 50%. Our data highlight DXM as a novel candidate for adjunct treatment of preclinical or recent-onset type 1 diabetes.

Fluvoxamine inhibits Th1 and Th17 polarization and function by repressing glycolysis to attenuate autoimmune progression in type 1 diabetes

BACKGROUND

Fluvoxamine is one of the selective serotonin reuptake inhibitors (SSRIs) that are regarded as the first-line drugs to manage mental disorders. It has been also recognized with the potential to treat inflammatory diseases and viral infection. However, the effect of fluvoxamine on autoimmune diseases, particularly type 1 diabetes (T1D) and the related cellular and molecular mechanisms, are yet to be addressed.

METHOD

Herein in this report, we treated NOD mice with fluvoxamine for 2 weeks starting from 10-week of age to dissect the impact of fluvoxamine on the prevention of type 1 diabetes. We compared the differences of immune cells between 12-week-old control and fluvoxamine-treated mice by flow cytometry analysis. To study the mechanism involved, we extensively examined the characteristics of CD4+ T cells with fluvoxamine stimulation using RNA-seq analysis, real-time PCR, Western blot, and seahorse assay. Furthermore, we investigated the relevance of our data to human autoimmune diabetes.

RESULT

Fluvoxamine not only delayed T1D onset, but also decreased T1D incidence. Moreover, fluvoxamine-treated NOD mice showed significantly attenuated insulitis coupled with well-preserved β cell function, and decreased Th1 and Th17 cells in the peripheral blood, pancreatic lymph nodes (PLNs), and spleen. Mechanistic studies revealed that fluvoxamine downregulated glycolytic process by inhibiting phosphatidylinositol 3-kinase (PI3K)-AKT signaling, by which it restrained effector T (Teff) cell differentiation and production of proinflammatory cytokines.

CONCLUSION

Collectively, our study supports that fluvoxamine could be a viable therapeutic drug against autoimmunity in T1D setting.

Teplizumab: promises and challenges of a recently approved monoclonal antibody for the prevention of type 1 diabetes or preservation of residual beta cell function

INTRODUCTION

Type 1 diabetes (T1D) is a chronic autoimmune endocrinopathy with increasing incidence that results in the depletion of pancreatic beta cells and exogenous insulin dependence. Despite technological advances in insulin delivery, disease control remains suboptimal, while previous immunotherapy options have failed to prevent T1D. Recently, teplizumab, an immunomodulating monoclonal antibody, was approved to delay or prevent T1D.

AREAS COVERED

Five randomized controlled trials have tested different regimens of administration, mostly 14-day schemes with dose escalation. In participants with new-onset T1D, teplizumab delayed C-peptide decline, improved glycemic control, and reduced insulin demand for a median of 1 or 2 years. Studies in at-risk relatives of patients showed a decrease in T1D incidence during 2 years of follow-up. Subgroups of responders with unique metabolic and immunological characteristics were identified. Mild to moderate adverse effects were reported, including transient rash, cytopenia, nausea, vomiting, and infections.

EXPERT OPINION

Teplizumab marks a turning point in T1D therapy. Areas of future research include the ideal population for screening, cost-effectiveness, and challenges in treatment accessibility. More studies are essential to evaluate the ideal duration of the regimen, the potential benefit of combinations with other drugs, and to identify endophenotypes with a high probability of response.

Discordant Effects of Polyamine Depletion by DENSpm and DFMO on β-cell Cytokine Stress and Diabetes Outcomes in Mice

Type 1 diabetes (T1D) is an autoimmune disease leading to dysfunction and loss of insulin-secreting β cells. In β cells, polyamines have been implicated in causing cellular stress and dysfunction. An inhibitor of polyamine biosynthesis, difluoromethylornithine (DFMO), has been shown to delay T1D in mouse models and preserve β-cell function in humans with recent-onset T1D. Another small molecule, N1,N11-diethylnorspermine (DENSpm), both inhibits polyamine biosynthesis and accelerates polyamine metabolism and is being tested for efficacy in cancer clinical trials. In this study, we show that DENSpm depletes intracellular polyamines as effectively as DFMO in mouse β cells. RNA-sequencing analysis, however, suggests that the cellular responses to DENSpm and DFMO differ, with both showing effects on cellular proliferation but the latter showing additional effects on mRNA translation and protein-folding pathways. In the low-dose streptozotocin-induced mouse model of T1D, DENSpm, unlike DFMO, did not prevent or delay diabetes outcomes but did result in improvements in glucose tolerance and reductions in islet oxidative stress. In nonobese diabetic (NOD) mice, short-term DENSpm administration resulted in a slight reduction in insulitis and proinflammatory Th1 cells in the pancreatic lymph nodes. Longer term treatment resulted in a dose-dependent increase in mortality. Notwithstanding the efficacy of both DFMO and DENSpm in reducing potentially toxic polyamine levels in β cells, our results highlight the discordant T1D outcomes that result from differing mechanisms of polyamine depletion and, more importantly, that toxic effects of DENSpm may limit its utility in T1D treatment.

The immunopathogenesis of narcolepsy type 1

Narcolepsy type 1 (NT1) is a chronic sleep disorder resulting from the loss of a small population of hypothalamic neurons that produce wake-promoting hypocretin (HCRT; also known as orexin) peptides. An immune-mediated pathology for NT1 has long been suspected given its exceptionally tight association with the MHC class II allele HLA-DQB1*06:02, as well as recent genetic evidence showing associations with polymorphisms of T cell receptor genes and other immune-relevant loci and the increased incidence of NT1 that has been observed after vaccination with the influenza vaccine Pandemrix. The search for both self-antigens and foreign antigens recognized by the pathogenic T cell response in NT1 is ongoing. Increased T cell reactivity against HCRT has been consistently reported in patients with NT1, but data demonstrating a primary role for T cells in neuronal destruction are currently lacking. Animal models are providing clues regarding the roles of autoreactive CD4+ and CD8+ T cells in the disease. Elucidation of the pathogenesis of NT1 will allow for the development of targeted immunotherapies at disease onset and could serve as a model for other immune-mediated neurological diseases.

Association between type 1 diabetes and systemic lupus erythematosus: a Mendelian randomization study

OBJECTIVES

Observational studies have shown that there is a bidirectional relationship between type 1 diabetes (T1D) and systemic lupus erythematosus (SLE); the causality of this association remains elusive and may be affected by confusion and reverse causality. There is also a lack of large-scale randomized controlled trials to verify. Therefore, this Mendelian randomization (MR) study aimed to investigate the causal association between T1D and SLE.

METHODS

We aggregated data using publicly available genome-wide association studies (GWAS), all from European populations. Select independent (R2 < 0.001) and closely related to exposure (P < 5 × 10-8) as instrumental variables (IVs). The inverse-variance weighted (IVW) method was used as the primary method. We also used MR-Egger, the weighted median method, MR-Robust, MR-Lasso, and other methods leveraged as supplements.

RESULTS

T1D had a positive causal association with SLE (IVW, odds ratio [OR] = 1.358, 95% confidence interval [CI], 1.205 - 1.530; P < 0.001). The causal association was verified in an independent validation set (IVW, OR = 1.137, 95% CI, 1.033 - 1.251; P = 0.001). SLE had a positive causal association with T1D (IVW, OR = 1.108, 95% CI, 1.074 - 1.144; P < 0.001). The causal association was verified in an independent validation set (IVW, OR = 1.085, 95% CI, 1.046 - 1.127; P < 0.001). These results have also been verified by sensitivity analysis.

CONCLUSION

The MR analysis results indicated a causal association between T1D and SLE. Therefore, further research is needed to clarify the potential biological mechanism between T1D and SLE. Key Points • Observational studies have shown that there is a bidirectional relationship between T1D and SLE. • We evaluated causal effects between T1D and SLE by Mendelian randomization analyses. • The MR analysis results indicated a causal association between T1D and SLE.

Epitope-based precision immunotherapy of Type 1 diabetes

Antigen-specific immunotherapies (ASITs) address important clinical needs in treating autoimmune diseases. However, Type 1 diabetes is a heterogeneous disease wherein patient characteristics influence responsiveness to ASITs. Targeting not only disease-relevant T cell populations, but also specific groups of patients using precision medicine is a new goal toward achieving effective treatment. HLA-restricted peptides provide advantages over protein as antigens, however, methods for profiling antigen-specific T cells need to improve in sensitivity, depth, and throughput to facilitate epitope selection. Delivery approaches are highly diverse, illustrating the many ways relevant antigen-presenting cell populations and anatomical locations can be targeted for tolerance induction. The role of persistence of antigen presentation in promoting durable antigen-specific tolerance requires further investigation. Based on the outcome of ASIT trials, the field is moving toward using patient-specific variations to improve efficacy, but challenges still lie on the path to delivering more effective and safer treatment to the T1D patient population.

Combination treatment of a novel CXCR3 antagonist ACT-777991 with an anti-CD3 antibody synergistically increases persistent remission in experimental models of type 1 diabetes

Treatment of patients with recent-onset type 1 diabetes with an anti-CD3 antibody leads to the transient stabilization of C-peptide levels in responder patients. Partial efficacy may be explained by the entry of islet-reactive T-cells spared by and/or regenerated after the anti-CD3 therapy. The CXCR3/CXCL10 axis has been proposed as a key player in the infiltration of autoreactive T cells into the pancreatic islets followed by the destruction of β cells. Combining the blockade of this axis using ACT-777991, a novel small-molecule CXCR3 antagonist, with anti-CD3 treatment may prevent further infiltration and β-cell damage and thus, preserve insulin production. The effect of anti-CD3 treatment on circulating T-cell subsets, including CXCR3 expression, in mice was evaluated by flow cytometry. Anti-CD3/ACT-777991 combination treatment was assessed in the virally induced RIP-LCMV-GP and NOD diabetes mouse models. Treatments started at disease onset. The effects on remission rate, blood glucose concentrations, insulitis, and plasma C-peptide were evaluated for the combination treatment and the respective monotherapies. Anti-CD3 treatment induced transient lymphopenia but spared circulating CXCR3+ T cells. Combination therapy in both mouse models synergistically and persistently reduced blood glucose concentrations, resulting in increased disease remission rates compared to each monotherapy. At the study end, mice in disease remission demonstrated reduced insulitis and detectable plasma C-peptide levels. When treatments were initiated in non-severely hyperglycemic NOD mice at diabetes onset, the combination treatment led to persistent disease remission in all mice. These results provide preclinical validation and rationale to investigate the combination of ACT-777991 with anti-CD3 for the treatment of patients with recent-onset diabetes.

An IL-2 mutein increases IL-10 and CTLA-4-dependent suppression of dendritic cells by regulatory T cells

Interleukin-2 (IL-2) variants with increased CD25 dependence that selectively expand Foxp3+ regulatory T (TR) cells are in clinical trials for treating inflammatory diseases. Using an Fc-fused IL-2 mutein (Fc.IL-2 mutein) we developed that prevents diabetes in non-obese diabetic (NOD) mice, we show that Fc.IL-2 mutein induced an activated TR population with elevated proliferation, a transcriptional program associated with Stat5- and TCR-dependent gene modules, and high IL-10 and CTLA-4 expression. Increased IL-10 signaling limited surface MHC class II upregulation during conventional dendritic cell (cDC) maturation, while increased CTLA-4-dependent transendocytosis led to the transfer of CD80 and CD86 costimulatory ligands from maturing cDCs to TR cells. In NOD mice, Fc.IL-2 mutein treatment promoted the suppression of cDCs in the inflamed pancreas and pancreatic lymph nodes resulting in T cell anergy. Thus, IL-2 mutein-expanded TR cells have enhanced functional properties and restrict cDC function, offering promise for targeted immunotherapy use in autoimmune disease.

Teplizumab in Type 1 Diabetes Mellitus: An Updated Review

Type 1 diabetes mellitus (T1DM) is a chronic autoimmune condition characterized by the irreversible destruction of the β cells of the pancreas, which leads to a lifelong dependency on exogenous insulin. Despite the advancements in insulin delivery methods, the suboptimal outcomes of these methods have triggered the search for therapies that may prevent or reverse the disease. Given the autoimmune aetiology of T1DM, therapies counteracting the immune-mediated destruction of the β-cells are the obvious target. Although several treatment strategies have been attempted to target cellular, humoral and innate immunity, very few have had a clinically meaningful impact. Of all the available immunomodulatory agents, cluster of differentiation (CD) 3 antibodies have exhibited the most promising preclinical and clinical results. Muromonab-CD3, which also happened to be a murine CD3 antibody, was the first monoclonal antibody approved for clinical use and was primarily indicated for graft rejection. The adverse effects associated with muromonab-CD3 led to its withdrawal. Teplizumab, a newer CD3 antibody, has a better side-effect profile because of its humanized nature and non-Fc-receptor-binding domain. In November 2022, teplizumab became the first immunomodulatory agent to be licensed by the US Food and Drug Administration for delaying the onset of T1DM in high-risk adults and children over 8 years old. The mechanism seems to be enhancing regulatory T-cell activity and promoting immune tolerance. This article reviews the mechanism of action and the clinical trials of teplizumab in individuals with T1DM or at risk of developing the disease.

PPARs at the crossroads of T cell differentiation and type 1 diabetes

T-cell-mediated autoimmune type 1 diabetes (T1D) is characterized by the immune-mediated destruction of pancreatic beta cells (β-cells). The increasing prevalence of T1D poses significant challenges to the healthcare system, particularly in countries with struggling economies. This review paper highlights the multifaceted roles of Peroxisome Proliferator-Activated Receptors (PPARs) in the context of T1D, shedding light on their potential as regulators of immune responses and β-cell biology. Recent research has elucidated the intricate interplay between CD4+ T cell subsets, such as Tregs and Th17, in developing autoimmune diseases like T1D. Th17 cells drive inflammation, while Tregs exert immunosuppressive functions, highlighting the delicate balance crucial for immune homeostasis. Immunotherapy has shown promise in reinstating self-tolerance and restricting the destruction of autoimmune responses, but further investigations are required to refine these therapeutic strategies. Intriguingly, PPARs, initially recognized for their role in lipid metabolism, have emerged as potent modulators of inflammation in autoimmune diseases, particularly in T1D. Although evidence suggests that PPARs affect the β-cell function, their influence on T-cell responses and their potential impact on T1D remains largely unexplored. It was noted that PPARα is involved in restricting the transcription of IL17A and enhancing the expression of Foxp3 by minimizing its proteasomal degradation. Thus, antagonizing PPARs may exert beneficial effects in regulating the differentiation of CD4+ T cells and preventing T1D. Therefore, this review advocates for comprehensive investigations to delineate the precise roles of PPARs in T1D pathogenesis, offering innovative therapeutic avenues that target both the immune system and pancreatic function. This review paper seeks to bridge the knowledge gap between PPARs, immune responses, and T1D, providing insights that may revolutionize the treatment landscape for this autoimmune disorder. Moreover, further studies involving PPAR agonists in non-obese diabetic (NOD) mice hold promise for developing novel T1D therapies.

Targeting β Cells with Cathelicidin Nanomedicines Improves Insulin Function and Pancreas Regeneration in Type 1 Diabetic Rats

Type 1 diabetes (T1D) is an incurable condition with an increasing incidence worldwide, in which the hallmark is the autoimmune destruction of pancreatic insulin-producing β cells. Cathelicidin-based peptides have been shown to improve β cell function and neogenesis and may thus be relevant while developing T1D therapeutics. In this work, a cathelicidin-derived peptide, LLKKK18, was loaded in poly(lactic-co-glycolic acid) (PLGA) nanoparticles (NPs), surface-functionalized with exenatide toward a GLP-1 receptor, aiming the β cell-targeted delivery of the peptide. The NPs present a mean size of around 100 nm and showed long-term stability, narrow size distribution, and negative ζ-potential (-10 mV). The LLKKK18 association efficiency and loading were 62 and 2.9%, respectively, presenting slow and sustained in vitro release under simulated physiologic fluids. Glucose-stimulated insulin release in the INS-1E cell line was observed in the presence of the peptide. In addition, NPs showed a strong association with β cells from isolated rat islets. After administration to diabetic rats, NPs induced a significant reduction of the hyperglycemic state, an improvement in the pancreatic insulin content, and glucose tolerance. Also remarkable, a considerable increase in the β cell mass in the pancreas was observed. Overall, this novel and versatile nanomedicine showed glucoregulatory ability and can pave the way for the development of a new generation of therapeutic approaches for T1D treatment.

Single-cell profiling reveals unique features of diabetogenic T cells in anti-PD-1-induced type 1 diabetes mice

Immune-related adverse events (irAEs) are a notable complication of PD-1 cancer immunotherapy. A better understanding of how these iatrogenic diseases compare with naturally arising autoimmune diseases is needed for treatment and monitoring of irAEs. We identified differences in anti-PD-1-induced type 1 diabetes (T1D) and spontaneous T1D in non-obese diabetic (NOD) mice by performing single-cell RNA-seq and TCR-seq on T cells from the pancreas, pancreas-draining lymph node (pLN), and blood of mice with PD-1-induced T1D or spontaneous T1D. In the pancreas, anti-PD-1 resulted in expansion of terminally exhausted/effector-like CD8+ T cells, an increase in T-bethi CD4+FoxP3- T cells, and a decrease in memory CD4+FoxP3- and CD8+ T cells in contrast to spontaneous T1D. Notably, anti-PD-1 caused increased TCR sharing between the pancreas and the periphery. Moreover, T cells in the blood of anti-PD-1-treated mice expressed markers that differed from spontaneous T1D, suggesting that the blood may provide a window to monitor irAEs rather than relying exclusively on the autoimmune target organ.

Sulforaphane: A nutraceutical against diabetes-related complications

There is an increasing interest in the use of nutraceuticals and plant-derived bioactive compounds from foods for their potential health benefits. For example, as a major active ingredient found from cruciferous vegetables like broccoli, there has been growing interest in understanding the therapeutic effects of sulforaphane against diverse metabolic complications. The past decade has seen an extensive growth in literature reporting on the potential health benefits of sulforaphane to neutralize pathological consequences of oxidative stress and inflammation, which may be essential in protecting against diabetes-related complications. In fact, preclinical evidence summarized within this review supports an active role of sulforaphane in activating nuclear factor erythroid 2-related factor 2 or effectively modulating AMP-activated protein kinase to protect against diabetic complications, including diabetic cardiomyopathy, diabetic neuropathy, diabetic nephropathy, as well as other metabolic complications involving non-alcoholic fatty liver disease and skeletal muscle insulin resistance. With clinical evidence suggesting that foods rich in sulforaphane like broccoli can improve the metabolic status and lower cardiovascular disease risk by reducing biomarkers of oxidative stress and inflammation in patients with type 2 diabetes. This information remains essential in determining the therapeutic value of sulforaphane or its potential use as a nutraceutical to manage diabetes and its related complications. Finally, this review discusses essential information on the bioavailability profile of sulforaphane, while also covering information on the pathological consequences of oxidative stress and inflammation that drive the development and progression of diabetes.

Lymph node sharing between pancreas, gut, and liver leads to immune crosstalk and regulation of pancreatic autoimmunity

Lymph nodes (LNs) are critical sites for shaping tissue-specific adaptive immunity. However, the impact of LN sharing between multiple organs on such tailoring is less understood. Here, we describe the drainage hierarchy of the pancreas, liver, and the upper small intestine (duodenum) into three murine LNs. Migratory dendritic cells (migDCs), key in instructing adaptive immune outcome, exhibited stronger pro-inflammatory signatures when originating from the pancreas or liver than from the duodenum. Qualitatively different migDC mixing in each shared LN influenced pancreatic β-cell-reactive T cells to acquire gut-homing and tolerogenic phenotypes proportional to duodenal co-drainage. However, duodenal viral infections rendered non-intestinal migDCs and β-cell-reactive T cells more pro-inflammatory in all shared LNs, resulting in elevated pancreatic islet lymphocyte infiltration. Our study uncovers immune crosstalk through LN co-drainage as a powerful force regulating pancreatic autoimmunity.

Stocking the toolbox-Using preclinical models to understand the development and treatment of immune checkpoint inhibitor-induced immune-related adverse events

Cancer patients treated with immune checkpoint inhibitors (ICIs) are susceptible to a broad and variable array of immune-related adverse events (irAEs). With increasing clinical use of ICIs, defining the mechanism for irAE development is more critical than ever. However, it currently remains challenging to predict when these irAEs occur and which organ may be affected, and for many of the more severe irAEs, inaccessibility to the tissue site hampers mechanistic insight. This lack of understanding of irAE development in the clinical setting emphasizes the need for greater use of preclinical models that allow for improved prediction of biomarkers for ICI-initiated irAEs or that validate treatment options that inhibit irAEs without hampering the anti-tumor immune response. Here, we discuss the utility of preclinical models, ranging from exploring databases to in vivo animal models, focusing on where they are most useful and where they could be improved.

Regulatory T cells targeting a pathogenic MHC class II: Insulin peptide epitope postpone spontaneous autoimmune diabetes

Introduction

In spontaneous type 1 diabetes (T1D) non-obese diabetic (NOD) mice, the insulin B chain peptide 9-23 (B:9-23) can bind to the MHC class II molecule (IAg7) in register 3 (R3), creating a bimolecular IAg7/InsulinB:9-23 register 3 conformational epitope (InsB:R3). Previously, we showed that the InsB:R3-specific chimeric antigen receptor (CAR), constructed using an InsB:R3-monoclonal antibody, could guide CAR-expressing CD8 T cells to migrate to the islets and pancreatic lymph nodes. Regulatory T cells (Tregs) specific for an islet antigen can broadly suppress various pathogenic immune cells in the islets and effectively halt the progression of islet destruction. Therefore, we hypothesized that InsB:R3 specific Tregs would suppress autoimmune reactivity in islets and efficiently protect against T1D.

Methods

To test our hypothesis, we produced InsB:R3-Tregs and tested their disease-protective effects in spontaneous T1D NOD.CD28-/- mice.

Results

InsB:R3-CAR expressing Tregs secrete IL-10 dominated cytokines upon engagement with InsB:R3 antigens. A single infusion of InsB:R3 Tregs delayed the onset of T1D in 95% of treated mice, with 35% maintaining euglycemia for two healthy lifespans, readily home to the relevant target whereas control Tregs did not. Our data demonstrate that Tregs specific for MHC class II: Insulin peptide epitope (MHCII/Insulin) protect mice against T1D more efficiently than polyclonal Tregs lacking islet antigen specificity, suggesting that the MHC II/insulin-specific Treg approach is a promising immune therapy for safely preventing T1D.

SOCS3 inhibits the mesenchymal stromal cell secretory factor SDF-1-mediated improvement of islet function in non-obese diabetic mice

BACKGROUND

Islet transplantation is used therapeutically in a minority of patients with type 1 diabetes (T1D). However, successful outcomes are hampered by early islet β-cell loss caused by immune rejection and autoimmunity. Recent studies have demonstrated that mesenchymal stromal cells can enhance islet function both in vitro and in vivo by secreting ligands that activate islet G-protein coupled receptors (GPCRs). Stromal cell-derived factor 1 (SDF-1) is an MSC-secreted GPCR ligand, whereas the suppressor of cytokine signaling 3 (SOCS3) is a negative regulator of STAT3-activating cytokines. Here, we determined whether improvement in islet function mediated by exogenous SDF-1 is impaired by SOCS3 in experimental models of T1D.

METHODS

Isolated islets were cultured for 48 h with SDF-1. Cytokine-induced apoptosis was measured immediately. Islets from Socs3^-/- mice were pre-cultured with exogenous SDF-1 and transplanted underneath the kidney capsule of C57BL/6 mice with streptozotocin-induced diabetes. Blood glucose levels were monitored for 28 days. AMD3100, an antagonist of the SDF-1 ligand CXCR4, was administered subcutaneously to islet transplanted mice to inhibit CXCR4 before and after transplantation.

RESULTS

SDF-1 protected islet cells from cytokine-induced apoptosis in vitro. SOCS3-knockout (KO) islets pretreated with SDF-1 were effective in reducing blood glucose in non-obese diabetic mice in vivo. We found that SDF-1 elicits localized immunosuppression in transplanted SOCS3-KO islets. Immunomodulation was observed when SOCS-KO islets were preconditioned with SDF-1. Gene expression and flow cytometric analyses revealed significantly decreased immune cell infiltration, inflammatory cytokines, and concomitant increases in FOXP3⁺ regulatory T cells, alternatively activated M2 macrophages, and dendritic cell phenotypes. Administration of AMD3100 impaired the SDF-1-mediated improvement in SOCS3-KO islet function and local immune suppression.

CONCLUSION

SDF-1 improves the function of islet grafts in autoimmune diabetes through regulation by CXCR4; however, the presence of SOCS3 reverses the protective effect of SDF-1 on islet grafts. These data reveal a molecular pathway that can elicit localized immunosuppression and delay graft destruction in transplanted islets.

Non-coding sequence variation reveals fragility within interleukin 2 feedback circuitry and shapes autoimmune disease risk

Genetic variants associated with human autoimmune diseases commonly map to non-coding control regions, particularly enhancers that function selectively in immune cells and fine-tune gene expression within a relatively narrow range of values. How such modest, cell-type-selective changes can meaningfully shape organismal disease risk remains unclear. To explore this issue, we experimentally manipulated species-conserved enhancers within the disease-associated IL2RA locus and studied accompanying changes in the progression of autoimmunity. Perturbing distinct enhancers with restricted activity in conventional T cells (Tconvs) or regulatory T cells (Tregs)-two functionally antagonistic T cell subsets-caused only modest, cell-type-selective decreases in IL2ra expression parameters. However, these same perturbations had striking and opposing effects in vivo , completely preventing or severely accelerating disease in a murine model of type 1 diabetes. Quantitative tissue imaging and computational modelling revealed that each enhancer manipulation impinged on distinct IL-2-dependent feedback circuits. These imbalances altered the intracellular signaling and intercellular communication dynamics of activated Tregs and Tconvs, producing opposing spatial domains that amplified or constrained ongoing autoimmune responses. These findings demonstrate how subtle changes in gene regulation stemming from non-coding variation can propagate across biological scales due to non-linearities in intra- and intercellular feedback circuitry, dramatically shaping disease risk at the organismal level.

Causal associations between type 1 diabetes and COVID-19 infection and prognosis: a two-sample Mendelian randomization study

INTRODUCTION

It has been suggested that type 1 diabetes was associated with increased COVID-19 morbidity and mortality. However, their causal relationship is still unclear. Herein, we performed a two-sample Mendelian randomization (MR) to investigate the causal effect of type 1 diabetes on COVID-19 infection and prognosis.

RESEARCH DESIGN AND METHODS

The summary statistics of type 1 diabetes were obtained from two published genome-wide association studies of European population, one as a discovery sample including 15 573 cases and 158 408 controls, and the other data as a replication sample consisting of 5913 cases and 8828 controls. We first performed a two-sample MR analysis to evaluate the causal effect of type 1 diabetes on COVID-19 infection and prognosis. Then, reverse MR analysis was conducted to determine whether reverse causality exists.

RESULTS

MR analysis results showed that the genetically predicted type 1 diabetes was associated with higher risk of severe COVID-19 (OR=1.073, 95% CI: 1.034 to 1.114, p_FDR=1.15×10^-3) and COVID-19 death (OR=1.075, 95% CI: 1.033 to 1.119, p_FDR=1.15×10^-3). Analysis of replication dataset showed similar results, namely a positive association between type 1 diabetes and severe COVID-19 (OR=1.055, 95% CI: 1.029 to 1.081, p_FDR=1.59×10^-4), and a positively correlated association with COVID-19 death (OR=1.053, 95% CI: 1.026 to 1.081, p_FDR=3.50×10^-4). No causal association was observed between type 1 diabetes and COVID-19 positive, hospitalized COVID-19, the time to the end of COVID-19 symptoms in the colchicine treatment group and placebo treatment group. Reverse MR analysis showed no reverse causality.

CONCLUSIONS

Type 1 diabetes had a causal effect on severe COVID-19 and death after COVID-19 infection. Further mechanistic studies are needed to explore the relationship between type 1 diabetes and COVID-19 infection and prognosis.

Tolerogenic IL-10-engineered dendritic cell-based therapy to restore antigen-specific tolerance in T cell mediated diseases

Tolerogenic dendritic cells play a critical role in promoting antigen-specific tolerance via dampening of T cell responses, induction of pathogenic T cell exhaustion and antigen-specific regulatory T cells. Here we efficiently generate tolerogenic dendritic cells by genetic engineering of monocytes with lentiviral vectors co-encoding for immunodominant antigen-derived peptides and IL-10. These transduced dendritic cells (designated DC^IL-10/Ag) secrete IL-10 and efficiently downregulate antigen-specific CD4⁺ and CD8⁺ T cell responses from healthy subjects and celiac disease patients in vitro. In addition, DC^IL-10/Ag induce antigen-specific CD49b⁺LAG-3⁺ T cells, which display the T regulatory type 1 (Tr1) cell gene signature. Administration of DC^IL-10/Ag resulted in the induction of antigen-specific Tr1 cells in chimeric transplanted mice and the prevention of type 1 diabetes in pre-clinical disease models. Subsequent transfer of these antigen-specific T cells completely prevented type 1 diabetes development. Collectively these data indicate that DC^IL-10/Ag represent a platform to induce stable antigen-specific tolerance to control T-cell mediated diseases.

Clonally expanded, thyrotoxic effector CD8+ T cells driven by IL-21 contribute to checkpoint inhibitor thyroiditis

Autoimmune toxicity occurs in up to 60% of patients treated with immune checkpoint inhibitor (ICI) therapy for cancer and represents an increasing clinical challenge for expanding the use of these treatments. To date, human immunopathogenic studies of immune-related adverse events (IRAEs) have relied on sampling of circulating peripheral blood cells rather than affected tissues. Here, we directly obtained thyroid specimens from individuals with ICI-thyroiditis, one of the most common IRAEs, and compared immune infiltrates with those from individuals with spontaneous autoimmune Hashimoto's thyroiditis (HT) or no thyroid disease. Single-cell RNA sequencing revealed a dominant, clonally expanded population of thyroid-infiltrating cytotoxic CXCR6+ CD8+ T cells (effector CD8+ T cells) present in ICI-thyroiditis but not HT or healthy controls. Furthermore, we identified a crucial role for interleukin-21 (IL-21), a cytokine secreted by intrathyroidal T follicular (TFH) and T peripheral helper (TPH) cells, as a driver of these thyrotoxic effector CD8+ T cells. In the presence of IL-21, human CD8+ T cells acquired the activated effector phenotype with up-regulation of the cytotoxic molecules interferon-γ (IFN-γ) and granzyme B, increased expression of the chemokine receptor CXCR6, and thyrotoxic capacity. We validated these findings in vivo using a mouse model of IRAEs and further demonstrated that genetic deletion of IL-21 signaling protected ICI-treated mice from thyroid immune infiltration. Together, these studies reveal mechanisms and candidate therapeutic targets for individuals who develop IRAEs.

Soluble antigen arrays improve the efficacy and safety of peptide-based tolerogenic immunotherapy

Autoantigen-specific immunotherapy using peptides offers a more targeted approach to treat autoimmune diseases, but the limited in vivo stability and uptake of peptides impedes clinical implementation. We previously showed that multivalent delivery of peptides as soluble antigen arrays (SAgAs) efficiently protects against spontaneous autoimmune diabetes in the non-obese diabetic (NOD) mouse model. Here, we compared the efficacy, safety, and mechanisms of action of SAgAs versus free peptides. SAgAs, but not their corresponding free peptides at equivalent doses, efficiently prevented the development of diabetes. SAgAs increased the frequency of regulatory T cells among peptide-specific T cells or induce their anergy/exhaustion or deletion, depending on the type of SAgA (hydrolysable (hSAgA) and non-hydrolysable 'click' SAgA (cSAgA)) and duration of treatment, whereas their corresponding free peptides induced a more effector phenotype following delayed clonal expansion. Moreover, the N-terminal modification of peptides with aminooxy or alkyne linkers, which was needed for grafting onto hyaluronic acid to make hSAgA or cSAgA variants, respectively, influenced their stimulatory potency and safety, with alkyne-functionalized peptides being more potent and less anaphylactogenic than aminooxy-functionalized peptides. Both SAgA variants significantly delayed anaphylaxis compared to their respective free peptides. The anaphylaxis, which occurred in NOD mice but not in C57BL/6 mice, was dose-dependent but did not correlate with the production of IgG1 or IgE against the peptides. We provide evidence that SAgAs significantly improve the efficacy and safety of peptide-based immunotherapy.

Abatacept for Delay of Type 1 Diabetes Progression in Stage 1 Relatives at Risk: A Randomized, Double-Masked, Controlled Trial

OBJECTIVE

Previous studies showed that inhibiting lymphocyte costimulation reduces declining β-cell function in individuals newly diagnosed with type 1 diabetes. We tested whether abatacept would delay or prevent progression of type 1 diabetes from normal glucose tolerance (NGT) to abnormal glucose tolerance (AGT) or to diabetes and the effects of treatment on immune and metabolic responses.

RESEARCH DESIGN AND METHODS

We conducted a phase 2, randomized, placebo-controlled, double-masked trial of abatacept in antibody-positive participants with NGT who received monthly abatacept/placebo infusions for 12 months. The end point was AGT or diabetes, assessed by oral glucose tolerance tests.

RESULTS

A total of 101 participants received abatacept and 111 placebo. Of these, 81 (35 abatacept and 46 placebo) met the end point of AGT or type 1 diabetes diagnosis (hazard ratio 0.702; 95% CI 0.452, 1.09; P = 0.11) The C-peptide responses to oral glucose tolerance tests were higher in the abatacept arm (P < 0.03). Abatacept reduced the frequency of inducible T-cell costimulatory (ICOS)+ PD1+ T-follicular helper (Tfh) cells during treatment (P < 0.0001), increased naive CD4+ T cells, and also reduced the frequency of CD4+ regulatory T cells (Tregs) from the baseline (P = 0.0067). Twelve months after treatment, the frequency of ICOS+ Tfh, naive CD4+ T cells, and Tregs returned to baseline.

CONCLUSIONS

Although abatacept treatment for 1 year did not significantly delay progression to glucose intolerance in at-risk individuals, it impacted immune cell subsets and preserved insulin secretion, suggesting that costimulation blockade may modify progression of type 1 diabetes.

Vitamin D in Diabetes: Uncovering the Sunshine Hormone's Role in Glucose Metabolism and Beyond

Over the last decades, epidemiology and functional studies have started to reveal a pivotal role of vitamin D in both type 1 and type 2 diabetes pathogenesis. Acting through the vitamin D receptor (VDR), vitamin D regulates insulin secretion in pancreatic islets and insulin sensitivity in multiple peripheral metabolic organs. In vitro studies and both T1D and T2D animal models showed that vitamin D can improve glucose homeostasis by enhancing insulin secretion, reducing inflammation, reducing autoimmunity, preserving beta cell mass, and sensitizing insulin action. Conversely, vitamin D deficiency has been shown relevant in increasing T1D and T2D incidence. While clinical trials testing the hypothesis that vitamin D improves glycemia in T2D have shown conflicting results, subgroup and meta-analyses support the idea that raising serum vitamin D levels may reduce the progression from prediabetes to T2D. In this review, we summarize current knowledge on the molecular mechanisms of vitamin D in insulin secretion, insulin sensitivity, and immunity, as well as the observational and interventional human studies investigating the use of vitamin D as a treatment for diabetes.

Lentinan confers protection against type 1 diabetes by inducing regulatory T cell in spontaneous non-obese diabetic mice

BACKGROUND

Lentinan (LNT) is a complex fungal component that possesses effective antitumor and immunostimulating properties. However, there is a paucity of studies regarding the effects and mechanisms of LNT on type 1 diabetes.

OBJECTIVE

In the current study, we investigated whether an intraperitoneal injection of LNT can diminish the risk of developing type 1 diabetes (T1D) in non-obese diabetic (NOD) mice and further examined possible mechanisms of LNT's effects.

METHODS

Pre-diabetic female NOD mice 8 weeks of age, NOD mice with 140-160 mg/dL, 200-230 mg/dL or 350-450 mg/dL blood glucose levels were randomly divided into two groups and intraperitoneally injected with 5 mg/kg LNT or PBS every other day. Then, blood sugar levels, pancreas slices, spleen, PnLN and pancreas cells from treatment mice were examined.

RESULTS

Our results demonstrated that low-dosage injections (5 mg/kg) of LNT significantly suppressed immunopathology in mice with autoimmune diabetes but increased the Foxp3+ regulatory T cells (Treg cells) proportion in mice. LNT treatment induced the production of Tregs in the spleen and PnLN cells of NOD mice in vitro. Furthermore, the adoptive transfer of Treg cells extracted from LNT-treated NOD mice confirmed that LNT induced Treg function in vivo and revealed an enhanced suppressive capacity as compared to the Tregs isolated from the control group.

CONCLUSION

LNT was capable of stimulating the production of Treg cells from naive CD4 + T cells, which implies that LNT exhibits therapeutic values as a tolerogenic adjuvant and may be used to reverse hyperglycaemia in the early and late stages of T1D.

I-Ag7 β56/57 polymorphisms regulate non-cognate negative selection to CD4+ T cell orchestrators of type 1 diabetes

Genetic susceptibility to type 1 diabetes is associated with homozygous expression of major histocompatibility complex class II alleles that carry specific beta chain polymorphisms. Why heterozygous expression of these major histocompatibility complex class II alleles does not confer a similar predisposition is unresolved. Using a nonobese diabetic mouse model, here we show that heterozygous expression of the type 1 diabetes-protective allele I-Ag7 β56P/57D induces negative selection to the I-Ag7-restricted T cell repertoire, including beta-islet-specific CD4+ T cells. Surprisingly, negative selection occurs despite I-Ag7 β56P/57D having a reduced ability to present beta-islet antigens to CD4+ T cells. Peripheral manifestations of non-cognate negative selection include a near complete loss of beta-islet-specific CXCR6+ CD4+ T cells, an inability to cross-prime islet-specific glucose-6-phosphatase catalytic subunit-related protein and insulin-specific CD8+ T cells and disease arrest at the insulitis stage. These data reveal that negative selection on non-cognate self-antigens in the thymus can promote T cell tolerance and protection from autoimmunity.

Using mass spectrometry to identify neoantigens in autoimmune diseases: The type 1 diabetes example

In autoimmune diseases, recognition of self-antigens presented by major histocompatibility complex (MHC) molecules elicits unexpected attack of tissue by autoantibodies and/or autoreactive T cells. Post-translational modification (PTM) may alter the MHC-binding motif or TCR contact residues in a peptide antigen, transforming the tolerance to self to autoreactivity. Mass spectrometry-based immunopeptidomics provides a valuable mechanism for identifying MHC ligands that contain PTMs and can thus provide valuable insights into pathogenesis and therapeutics of autoimmune diseases. A plethora of PTMs have been implicated in this process, and this review highlights their formation and identification.

Berberine Regulates GPX4 to Inhibit Ferroptosis of Islet β Cells

Ferroptosis, as a kind of non-apoptotic cell death, is involved in the pathogenesis of type 1 diabetes mellitus (T1DM). Islet B cells mainly produce insulin that is used to treat diabetes. Berberine (BBR) can ameliorate type 2 diabetes and insulin resistance in many ways. However, a few clues concerning the mechanism of BBR regulating ferroptosis of islet β cells in T1DM have been detected so far. We measured the effects of BBR and GPX4 on islet β cell viability and proliferation by MTT and colony formation assays. Western blot and qRT-PCR were utilized to examine GPX4 expression in islet β cells with distinct treatments. The influence of BBR and GPX4 on ferroptosis of islet β cells was investigated by evaluating the content of Fe²⁺ and reactive oxygen species (ROS) in cells. The mechanism of BBR targeting GPX4 to inhibit ferroptosis of islet β cells was further revealed by the rescue experiment. Our results showed that BBR and overexpression of GPX4 could notably accelerate cell viability and the proliferative abilities of islet β cells. Moreover, BBR stimulated GPX4 expression to reduce the content of Fe²⁺ and ROS, thereby repressing the ferroptosis of islet β cells, which functioned similarly as ferroptosis inhibitor Fer-1. In conclusion, BBR suppressed ferroptosis of islet β cells via promoting GPX4 expression, providing new insights into the mechanism of BBR for islet β cells.

The interplay of inflammation, exosomes and Ca2+ dynamics in diabetic cardiomyopathy

Diabetes mellitus is one of the prime risk factors for cardiovascular complications and is linked with high morbidity and mortality. Diabetic cardiomyopathy (DCM) often manifests as reduced cardiac contractility, myocardial fibrosis, diastolic dysfunction, and chronic heart failure. Inflammation, changes in calcium (Ca²⁺) handling and cardiomyocyte loss are often implicated in the development and progression of DCM. Although the existence of DCM was established nearly four decades ago, the exact mechanisms underlying this disease pathophysiology is constantly evolving. Furthermore, the complex pathophysiology of DCM is linked with exosomes, which has recently shown to facilitate intercellular (cell-to-cell) communication through biomolecules such as micro RNA (miRNA), proteins, enzymes, cell surface receptors, growth factors, cytokines, and lipids. Inflammatory response and Ca²⁺ signaling are interrelated and DCM  has been known to adversely affect many of these signaling molecules either qualitatively and/or quantitatively. In this literature review, we have demonstrated that Ca²⁺ regulators are tightly controlled at different molecular and cellular levels during various biological processes in the heart. Inflammatory mediators, miRNA and exosomes are shown to interact with these regulators, however how these mediators are linked to Ca²⁺ handling during DCM pathogenesis remains elusive. Thus, further investigations are needed to understand the mechanisms to restore cardiac Ca²⁺ homeostasis and function, and to serve as potential therapeutic targets in the treatment of DCM.

Effects of Aire on perforin expression in BMDCs via TLR7/8 and its therapeutic effect on type 1 diabetes

AIMS

Type 1 diabetes, as a kind of autoimmune diseases, usually results from the broken-down of self-tolerance. Autoimmune regulator (Aire), as a transcription factor, induces peripheral tolerance by regulating Toll-like receptor (TLR) expression in dendritic cells (DCs). Several studies have recently identified a small population of perforin-expressing DCs, which is an important population of tolerogenic DCs (tolDCs) that restricts autoreactive T cells in vivo through a perforin-mediated mechanism. Thus, the present study explored the specific relationship among Aire, perforin-expressing DCs and immune tolerance, as well as their roles in type 1 diabetes.

METHODS

We conducted studies based on the Aire-overexpressing bone marrow-derived dendritic cell (BMDC) model. And through in vitro and in vivo experiments to observe that Aire-overexpressing BMDCs which express perforin induce immune tolerance and treat type 1 diabetes via TLR7/8.

RESULTS

Aire enhances the expression of perforin in BMDCs after treatment with the TLR7/8 ligand as well as promotes the expression of TLR7/8 and myeloid differentiation primary response gene 88 (MyD88)-dependent pathway molecules. Aire-overexpressing BMDCs mediate apoptosis of allogeneic CD8⁺ T cells via perforin in vitro. Moreover, Aire-overexpressing BMDCs enhance the therapeutic effect of type 1 diabetes in non-obese diabetic (NOD) mice via perforin and induce apoptosis of autoreactive CD8⁺ T cells in vivo.

CONCLUSIONS

These results provide an experimental basis for comprehensively elucidating the role and significance of Aire expression in peripheral DCs, thereby providing new ideas for the treatment of autoimmune diseases by using Aire as a target to induce the production of perforin-expressing DCs.

Maternal hypertensive disorders during pregnancy and the risk of offspring diabetes mellitus in childhood, adolescence, and early adulthood: a nationwide population-based cohort study

BACKGROUND

Maternal hypertensive disorders during pregnancy (HDP) have been suggested to contribute to the development of offspring cardiovascular disease later in life, but empirical evidence remains inconsistent. This study was aimed to assess the association of maternal overall and type-specific HDPs with diabetes in offspring from childhood to early adulthood.

METHODS

Using Danish national health registers, a total of 2,448,753 individuals born in Denmark from 1978 to 2018 were included in this study. Maternal HDP included chronic hypertension, gestational hypertension, and preeclampsia. The outcome of interest was diabetes in offspring (including type 1, type 2, and gestational diabetes). The follow-up of offspring started at birth and ended at the first diagnosis of diabetes, emigration from Denmark, death, or time end on 31 December 2018, whichever came first. Cox proportional hazards regression was used to evaluate the hazard ratios (HRs) with 95% confidence intervals (CIs) of the association between maternal HDP and diabetes (including type 1, type 2, and gestational diabetes) in offspring from birth to young adulthood (up to 41 years), with the offspring's age as the time scale.

RESULTS

During a follow-up of up to 41 (median: 19.3) years, 1247 offspring born to mothers with HDP and 23,645 offspring born to mothers without HDP were diagnosed with diabetes. Compared with offspring born to mothers without HDP, those born to mothers with HDP had an increased risk for overall diabetes (HR=1.27, 95% CI=1.20-1.34), as well as for type 2 diabetes (HR=1.57, 95% CI=1.38-1.78) and gestational diabetes (HR=1.37, 95% CI=1.25-1.49). We did not observe obvious increased risk for type 1 diabetes (HR=1.08, 95% CI=0.98-1.18). Offspring of mothers with gestational hypertension (HR=1.37, 95% CI=1.00-1.88) or preeclampsia (HR=1.62, 95% CI=1.41-1.87) had higher risks of type 2 diabetes. The strongest association was observed for severe preeclampsia, with a 2-fold risk of type 2 diabetes (HR=2.00, 95% CI=1.42-2.82). The association between maternal HDP and type 1 diabetes did not reach statistical significance, except for maternal gestational hypertension (HR=1.41, 95%CI=1.17-1.71). In addition, we found that offspring born to mothers with any subtypes of maternal HDP had higher risk of gestational diabetes, and the corresponding HRs (95%CIs) for chronic hypertension, gestational hypertension, and preeclampsia were 1.60 (1.06-2.41), 1.29 (1.04-1.59), and 1.38 (1.24-1.53), respectively. We also observed stronger associations among offspring of mothers with HDP and comorbid diabetes (HR=4.64, 95%CI=3.85-5.60) than offspring of mothers with HDP or diabetes alone.

CONCLUSIONS

Offspring of mothers with HDP, especially mothers with comorbid diabetes, had an increased risk of diabetes later in their life. Our findings suggest that timely and effective prevention of HDP in women of childbearing age should be taken into consideration as diabetes prevention and control strategies for their generations.

How to create an experimental diabetes mellitus model?

Diabetes is a metabolic disorder characterized by chronic hyperglycemia. Early treatment is very important in terms of preventing diabetes-related late complications with high treatment costs and increasing the patient’s quality of life. In addition to investigating the pathophysiology of the disease studied, animal experiments pave the way for new approaches in treatments. Although there are many methods that can be used when creating a diabetes model, induction of diabetes with alloxan and streptozotocin are the most preferred ones. The aim of this article is to review the available information on diabetes-related methods, common problems and solutions, with known mechanisms of action, dose and time-determined methods.

New-onset type 1 diabetes and Graves' disease after antiretroviral therapy in a patient with human immunodeficiency virus infection

Patients with human immunodeficiency virus (HIV) infection receiving antiretroviral therapy can develop autoimmune diseases, referred to as immune-inflammatory reconstitution syndrome. Nevertheless, only a few reports on the onset of type 1 diabetes as immune-inflammatory reconstitution syndrome are available. A 40-year-old Japanese man with HIV infection was initiated with antiretroviral therapy at the age of 29 years. He developed Graves' disease at 35 years and diabetes, with a hemoglobin A1c of 6.5%, and maintained insulin secretion at 38 years. His antiglutamic acid decarboxylase antibody level was >2,000 U/mL, and he was diagnosed with slowly progressive type 1 diabetes. At the age of 40 years, he was admitted to our hospital with diabetic ketosis. We retrospectively assayed his stored plasma samples for thyroid-stimulating hormone receptor antibody and antiglutamic acid decarboxylase antibody, which showed positive conversion after initiating antiretroviral therapy, suggesting that Graves' disease and type 1 diabetes developed as a probable result of immune-inflammatory reconstitution syndrome.

Proteomic identification of MHC class I-associated peptidome derived from non-obese diabetic mouse thymus and pancreas

The peptides repertoire presented to CD8⁺ T cells by major histocompatibility complex (MHC) class I molecules is referred to as the MHC I-associated peptidome (MIP), which regulates thymus development, peripheral survival and function during lifetime of CD8⁺ T cells. Type 1 diabetes (T1D) is an organ-specific autoimmune disease caused by pancreatic β cells destruction mediated primarily by autoreactive CD8⁺ T cells. Non-obese diabetic (NOD) mouse is an important animal model of T1D. Here, we deeply analyzed the MIP derived from NOD mice thymus and pancreas, and demonstrated that the thymus MIP source proteins partially shared with the MIP source proteins derived from NOD mice pancreas and β cell line. One H-2Kd restricted peptide SLC35B1_26-34 which was shared by MIP derived from both NOD mice pancreatic tissues and islet β-cell line, but absent in MIP from NOD thymus tissues, showed ability to stimulate IFN-γ secretion and proliferation of NOD mice splenic CD8⁺ T cells. The global view of the MHC I-associated self-peptides repertoire in the thymus and pancreas of NOD mice may serve as a biological reference to identify potential autoantigens targeted by autoreactive CD8⁺ T cells in T1D. Data are available via ProteomeXchange with identifier PXD031966. SIGNIFICANCE: The peptides repertoire presented to CD8⁺ T cells by major histocompatibility complex (MHC) class I molecules is referred to as the MHC I-associated peptidome (MIP). The MIP presented by thymic antigen presenting cells (APCs) is crucial for shaping CD8⁺ T cell repertoire and self-tolerance, while the MIP presented by peripheral tissues and organs is not only involved in maintaining periphery CD8⁺ T cell survival and homeostasis, but also mediates immune surveillance and autoimmune responses of CD8⁺ T cells under pathological conditions. Type 1 diabetes (T1D) is an organ-specific autoimmune disease caused by the destruction of pancreatic β cells, mediated primarily by autoreactive CD8⁺ T cells. Non-obese diabetic (NOD) mouse is one of important animal models of spontaneous autoimmune diabetes that shares several key features with human T1D. The global view of the MHC I-associated self-peptides repertoire in the thymus and pancreas of NOD mice may serve as a good biological reference to identify potential autoantigens targeted by autoreactive CD8⁺ T cells in T1D. It has great significance for further clarifying the immune recognition and effect mechanism of autoreactive CD8⁺ T cells in the pathogenesis of T1D, and then developing antigen-specific immune intervention strategies.

Longitudinal monitoring of pancreatic islet damage in streptozotocin-treated mice with optical coherence microscopy

Pancreatic islets regulate glucose homeostasis in the body, and their dysfunction is closely related to diabetes. Islet transplantation into the anterior chamber of the eye (ACE) was recently developed for both in vivo islet study and diabetes treatment. Optical coherence microscopy (OCM) was previously used to monitor ACE transplanted islets in non-obese diabetic (NOD) mice for detecting autoimmune attack. In this study, OCM was applied to streptozotocin (STZ)-induced diabetic mouse models for the early detection of islet damage. A custom extended-focus OCM (xfOCM) was used to image islet grafts in the ACE longitudinally during STZ-induced beta cell destruction together with conventional bright-field (BF) imaging and invasive glucose level measurement. xfOCM detected local structural changes and vascular degradation during the islet damage which was confirmed by confocal imaging of extracted islet grafts. xfOCM detection of islet damage was more sensitive than BF imaging and glucose measurement. Longitudinal xfOCM images of islet grafts were quantitatively analyzed. All these results showed that xfOCM could be used as a non-invasive and sensitive monitoring method for the early detection of deficient islet grafts in the ACE with potential applications to human subjects.

A discovery-based proteomics approach identifies protein disulphide isomerase (PDIA1) as a biomarker of β cell stress in type 1 diabetes

BACKGROUND

Stress responses within the β cell have been linked with both increased β cell death and accelerated immune activation in type 1 diabetes (T1D). At present, information on the timing and scope of these responses as well as disease-related changes in islet β cell protein expression during T1D development is lacking.

METHODS

Data independent acquisition-mass spectrometry was performed on islets collected longitudinally from NOD mice and NOD-SCID mice rendered diabetic through T cell adoptive transfer.

FINDINGS

In islets collected from female NOD mice at 10, 12, and 14 weeks of age, we found a time-restricted upregulation of proteins involved in stress mitigation and maintenance of β cell function, followed by loss of expression of protective proteins that heralded diabetes onset. EIF2 signalling and the unfolded protein response, mTOR signalling, mitochondrial function, and oxidative phosphorylation were commonly modulated pathways in both NOD mice and NOD-SCID mice rendered acutely diabetic by T cell adoptive transfer. Protein disulphide isomerase A1 (PDIA1) was upregulated in NOD islets and pancreatic sections from human organ donors with autoantibody positivity or T1D. Moreover, PDIA1 plasma levels were increased in pre-diabetic NOD mice and in the serum of children with recent-onset T1D compared to non-diabetic controls.

INTERPRETATION

We identified a core set of modulated pathways across distinct mouse models of T1D and identified PDIA1 as a potential human biomarker of β cell stress in T1D.

FUNDING

NIH (R01DK093954, DK127308, U01DK127786, UC4DK104166, R01DK060581, R01GM118470, and 5T32DK101001-09). VA Merit Award I01BX001733. JDRF (2-SRA-2019-834-S-B, 2-SRA-2018-493-A-B, 3-PDF-20016-199-A-N, 5-CDA-2022-1176-A-N, and 3-PDF-2017-385-A-N).

Pancreatic Islet Cells Response to IFNγ Relies on Their Spatial Location within an Islet

Type 1 diabetes (T1D) is an auto-immune disease characterized by the progressive destruction of insulin-producing pancreatic beta cells. While beta cells are the target of the immune attack, the other islet endocrine cells, namely the alpha and delta cells, can also be affected by the inflammatory milieu. Here, using a flow cytometry-based strategy, we compared the impact of IFNγ, one of the main cytokines involved in T1D, on the three endocrine cell subsets isolated from C57BL/6 mouse islets. RNA-seq analyses revealed that alpha and delta cells exposed in vitro to IFNγ display a transcriptomic profile very similar to that of beta cells, with an increased expression of inflammation key genes such as MHC class I molecules, the CXCL10 chemokine and the programmed death-ligand 1 (PD-L1), three hallmarks of IFNγ signaling. Interestingly, at low IFNγ concentration, we observed two beta cell populations (responders and non-responders) based on PD-L1 protein expression. Our data indicate that this differential sensitivity relies on the location of the cells within the islet rather than on the existence of two different beta cells subsets. The same findings were corroborated by the in vivo analysis of pancreatic islets from the non-obese diabetic mouse model of T1D, showing more intense PD-L1 staining on endocrine cells close to immune infiltrate. Collectively, our work demonstrates that alpha and delta cells are as sensitive as beta cells to IFNγ, and suggests a gradual diffusion of the cytokine into an islet. These observations provide novel insights into the in situ inflammatory processes occurring in T1D progression.

Insulitis in Human Type 1 Diabetic Pancreas: From Stem Cell Grafting to Islet Organoids for a Successful Cell-Based Therapy

Type 1 diabetes (T1D) is an autoimmune disease with immune cells' islet infiltration (called "insulitis"), which leads to beta cell loss. Despite being the critical element of T1D occurrence and pathogenesis, insulitis is often present in a limited percentage of islets, also at diagnosis. Therefore, it is needed to define reproducible methods to detect insulitis and beta-cell decline, to allow accurate and early diagnosis and to monitor therapy. However, this goal is still far due to the morphological aspect of islet microvasculature, which is rather dense and rich, and is considerably rearranged during insulitis. More studies on microvasculature are required to understand if contrast-enhanced ultrasound sonography measurements of pancreatic blood-flow dynamics may provide a clinically deployable predictive marker to predict disease progression and therapeutic reversal in pre-symptomatic T1D patients. Therefore, it is needed to clarify the relation between insulitis and the dynamics of β cell loss and with coexisting mechanisms of dysfunction, according to clinical stage, as well as the micro vessels' dynamics and microvasculature reorganization. Moreover, the ideal cell-based therapy of T1D should start from an early diagnosis allowing a sufficient isolation of specific Procr+ progenitors, followed by the generation and expansion of islet organoids, which could be transplanted coupled to an immune-regulatory therapy which will permit the maintenance of pancreatic islets and an effective and long-lasting insulitis reversal.

Pancreatic islet-specific engineered Tregs exhibit robust antigen-specific and bystander immune suppression in type 1 diabetes models

Adoptive transfer of regulatory T cells (T_regs) is therapeutic in type 1 diabetes (T1D) mouse models. T_regs that are specific for pancreatic islets are more potent than polyclonal T_regs in preventing disease. However, the frequency of antigen-specific natural T_regs is extremely low, and ex vivo expansion may destabilize T_regs, leading to an effector phenotype. Here, we generated durable, antigen-specific engineered T_regs (EngT_regs) from primary human CD4⁺ T cells by combining FOXP3 homology-directed repair editing and lentiviral T cell receptor (TCR) delivery. Using TCRs derived from clonally expanded CD4⁺ T cells isolated from patients with T1D, we generated islet-specific EngT_regs that suppressed effector T cell (T_eff) proliferation and cytokine production. EngT_regs suppressed T_effs recognizing the same islet antigen in addition to bystander T_effs recognizing other islet antigens through production of soluble mediators and both direct and indirect mechanisms. Adoptively transferred murine islet-specific EngT_regs homed to the pancreas and blocked diabetes triggered by islet-specific T_effs or diabetogenic polyclonal T_effs in recipient mice. These data demonstrate the potential of antigen-specific EngT_regs as a targeted therapy for preventing T1D.

How dysregulation of the immune system promotes diabetes mellitus and cardiovascular risk complications

Diabetes mellitus (DM) is a chronic metabolic disorder characterized by persistent hyperglycemia due to insulin resistance or failure to produce insulin. Patients with DM develop microvascular complications that include chronic kidney disease and retinopathy, and macrovascular complications that mainly consist in an accelerated and more severe atherosclerosis compared to the general population, increasing the risk of cardiovascular (CV) events, such as stroke or myocardial infarction by 2- to 4-fold. DM is commonly associated with a low-grade chronic inflammation that is a known causal factor in its development and its complications. Moreover, it is now well-established that inflammation and immune cells play a major role in both atherosclerosis genesis and progression, as well as in CV event occurrence. In this review, after a brief presentation of DM physiopathology and its macrovascular complications, we will describe the immune system dysregulation present in patients with type 1 or type 2 diabetes and discuss its role in DM cardiovascular complications development. More specifically, we will review the metabolic changes and aberrant activation that occur in the immune cells driving the chronic inflammation through cytokine and chemokine secretion, thus promoting atherosclerosis onset and progression in a DM context. Finally, we will discuss how genetics and recent systemic approaches bring new insights into the mechanisms behind these inflammatory dysregulations and pave the way toward precision medicine.

CXCR3 antagonist AMG487 ameliorates experimental autoimmune prostatitis by diminishing Th1 cell differentiation and inhibiting macrophage M1 phenotypic activation

BACKGROUND

Chronic prostatitis and chronic pelvic pain syndrome (CP/CPPS) is an inflammatory immune disease that is characterized by infiltrating inflammatory cells in the prostate and pelvic or by perineal pain. Receptor CXCR3modulates immune and inflammatory responses; however, the effects of CXCR3 antagonist AMG487 in the context of CP/CPPS are unknown. Therefore, we investigated the effect of AMG487 in experimental autoimmune prostatitis (EAP) mice and explored the potential functional mechanisms.

METHODS

The EAP model was induced by intradermally injecting a mixture of prostate antigens and complete Freund's adjuvant on Days 0 and 28. To evaluate the effect of AMG487 on EAP mice, treatment with AMG487 and vehicle solution was conducted for the indicated period. Then, procedures were performed, including behavioral test, to evaluate the pain response to stimulation before the mice were killed and a histological assessment to evaluate the inflammation after the mice were killed. Immunofluorescence, flow cytometry, and Western blot assay were used to analyze the functional phenotype and regulation mechanism of AMG487 on T helper type 1 (Th1) cells and macrophages.

RESULTS

We found high expression of CXCR3 in human benign prostate tissues with inflammation and EAP mice. The elevated CXCR3 in prostate tissues correlates with the severity of inflammation. CXCR3 antagonist AMG487 treatment ameliorated the inflammatory changes and the pelvic pain of EAP mice. AMG487 inhibits Th1 cell differentiation through the IL-12/STAT4pathway and inhibits pro-inflammatory M1 macrophages through the lipopolysaccharide/NF-κB p65signaling. AMG487 could inhibit the secretion of inflammatory mediators in EAP mice.

CONCLUSION

CXCR3 antagonist AMG487 could ameliorate the inflammatory changes and the pelvic pain of EAP mice by diminishing Th1 cell differentiation and inhibiting macrophage M1 phenotypic activation. Thus, the results imply that AMG487 has the potential as an effective therapeutic agent in the prevention and treatment of EAP.

Using the Collaborative Cross and Diversity Outbred Mice in Immunology

The Collaborative Cross (CC) and the Diversity Outbred (DO) stock mouse panels are the most powerful murine genetics tools available to the genetics community. Together, they combine the strength of inbred animal models with the diversity of outbred populations. Using the 63 CC strains or a panel of DO mice, each derived from the same 8 parental mouse strains, researchers can map genetic contributions to exceptionally complex immunological and infectious disease traits that would require far greater powering if performed by genome-wide association studies (GWAS) in human populations. These tools allow genes to be studied in heterozygous and homozygous states and provide a platform to study epistasis between interacting loci. Most importantly, once a quantitative phenotype is investigated and quantitative trait loci are identified, confirmatory genetic studies can be performed, which is often problematic using the GWAS approach. In addition, novel stable mouse models for immune phenotypes are often derived from studies utilizing the DO and CC mice that can serve as stronger model systems than existing ones in the field. The CC/DO systems have contributed to the fields of cancer immunology, autoimmunity, vaccinology, infectious disease, allergy, tissue rejection, and tolerance but have thus far been greatly underutilized. In this article, we present a recent review of the field and point out key areas of immunology that are ripe for further investigation and awaiting new CC/DO research projects. We also highlight some of the strong computational tools that have been developed for analyzing CC/DO genetic and phenotypic data. Additionally, we have formed a centralized community on the CyVerse infrastructure where immunogeneticists can utilize those software tools, collaborate with groups across the world, and expand the use of the CC and DO systems for investigating immunogenetic phenomena. © 2022 Wiley Periodicals LLC.

Immunological balance between Treg and Th17 lymphocytes as a key element of type 1 diabetes progression in children

Type 1 diabetes (T1D) is autoimmune destruction of the beta cells of pancreatic islets. Due to complexity of that disease, the mechanisms leading to the tolerance breakdown are still not fully understood. Previous hypothesis of imbalance in the Th1 and Th2 cells as the main contributing factor has been recently changed towards role of other lymphocytes – regulatory (Treg) and IL-17A-producing (Th17). Our study aims to assess changes within Treg and Th17 cells in newly diagnosed T1D pediatric patients and their association with disease remission. Flow cytometry implementation allowed for Treg and Th17 analysis in studied groups and further combination with clinical and laboratory data. In addition, expression of diabetes-related genes was tested and evaluated in context of their association with studied lymphocytes. Initial results revealed that Treg and ratio Treg/Th17 are significantly higher in T1D than in healthy controls. Moreover, patients with lower HbA1c and daily insulin requirements demonstrated higher levels of Tregs. Similar tendency for insulin intake was also observed in reference to Th17 cells, together with high levels of these cells in patients demonstrating higher values for c-peptide after 2 years. In low-level Treg patients, that subset correlates with the c-peptide in the admission stage. In addition, higher levels of IL-10 were associated with its correlation with HbA1c and insulin dosage. In the context of gene expression, moderate associations were demonstrated in T1D subjects inter alia between CTLA4 and Treg or ratio Treg/Th17. Cumulatively, our data indicate a possible novel role of Treg and Th17 in mechanism of type 1 diabetes. Moreover, potential prognostic value of these populations has been shown in reference to diabetes remission.

Inhibition of IL-17A Protects against Thyroid Immune-Related Adverse Events while Preserving Checkpoint Inhibitor Antitumor Efficacy

Immune checkpoint inhibitor (ICI) immunotherapy leverages the body's own immune system to attack cancer cells but leads to unwanted autoimmune side effects in up to 60% of patients. Such immune-related adverse events (IrAEs) may lead to treatment interruption, permanent organ dysfunction, hospitalization, and premature death. Thyroiditis is one of the most common IrAEs, but the cause of thyroid IrAEs remains unknown. In this study, we use a new, physiologically relevant mouse model of ICI-associated autoimmunity to identify a key role for type 3 immune cells in the development of thyroid IrAEs. Multiple lineages of IL-17A-producing T cells expand in thyroid tissue with ICI treatment. Intrathyroidal IL-17A-producing innate-like γδT17 cells were increased in tumor-free mice, whereas adaptive Th17 cells were also prominent in tumor-bearing mice, following ICI treatment. Furthermore, Ab-based inhibition of IL-17A, a clinically available therapy, significantly reduced thyroid IrAE development in ICI-treated mice with and without tumor challenge. Finally, combination of IL-17A neutralization with ICI treatment in multiple tumor models did not reduce ICI antitumor efficacy. These studies suggest that targeting Th17 and γδT17 cell function via the IL-17A axis may reduce IrAEs without impairing ICI antitumor efficacy and may be a generalizable strategy to address type 3 immune-mediated IrAEs.