The NOD mouse: a model of immune dysregulation

Akkermansia muciniphila restrains type 1 diabetes onset by eliciting cDC2 and Treg cell differentiation in NOD and STZ-induced experimental models

AIMS

Akkermansia muciniphila (A. muciniphila), a Gram-negative anaerobic mucus-layer-degrading bacterium found in the intestinal mucosa, exhibits potential as a probiotic, showing promise in mitigating autoimmune and chronic inflammatory diseases. This study aims to investigate whether A. muciniphila supplementation might confer protection against type 1 diabetes (T1D) and to elucidate the immunological pathways through which it exerts its beneficial effects.

MATERIALS AND METHODS

Non-obese diabetic (NOD) mice and streptozotocin (STZ)-induced type 1 diabetes (T1D) models were used to evaluate the protective effects of A. muciniphila during T1D course. Body weight, blood glucose levels, and T1D incidence were monitored. Immune responses in the pancreas, pancreatic (PLN) and cecal lymph nodes (CLN) and bone marrow-derived dendritic cells (BMDC) were evaluated by flow cytometry and ELISA.

KEY FINDINGS

Viable A. muciniphila supplementation conferred protection against T1D onset in STZ-induced T1D and NOD mouse models. T1D modulation by A. muciniphila in the STZ model was independent of the gut microbiota, and it was associated with increased tolerogenic type-2 dendritic cells (SIRP-α+CD11b+CD103+) and regulatory T (Treg) cells in PLN and pancreas. BMDC differentiated in the presence of A. muciniphila exhibited a tolerogenic profile and induced Treg cell generation in vitro. A. muciniphila-induced protection in T1D outcome was abrogated in FOXP3-DTR mice depleted of Treg cells, indicating that its mechanism of action is dependent on the CD4+Foxp3+ Treg cells.

SIGNIFICANCE

A. muciniphila supplementation attenuates T1D development in mice by modulating the tolerogenic immune response and is a promising new therapeutic tool for this autoimmune disease.

Single-cell RNA-seq reveals disease-specific CD8+ T cell clonal expansion and a high frequency of transcriptionally distinct double-negative T cells in diabetic NOD mice

T cells primarily drive the autoimmune destruction of pancreatic beta cells in Type 1 diabetes (T1D). However, the profound yet uncharacterized diversity of the T cell populations in vivo has hindered obtaining a clear picture of the T cell changes that occur longitudinally during T1D onset. This study aimed to identify T cell clonal expansion and distinct transcriptomic signatures associated with T1D progression in Non-Obese Diabetic (NOD) mice. Here we profiled the transcriptome and T cell receptor (TCR) repertoire of T cells at single-cell resolution from longitudinally collected peripheral blood and pancreatic islets of NOD mice using single-cell RNA sequencing technology. We detected disease dependent development of infiltrating CD8 + T cells with altered cytotoxic and inflammatory effector states. In addition, we discovered a high frequency of transcriptionally distinct double negative (DN) T cells that fluctuate throughout T1D pathogenesis. This study identifies potential disease relevant TCR sequences and potential disease biomarkers that can be further characterized through future research.

IFN-α Induces Heterogenous ROS Production in Human β-Cells

Type 1 diabetes (T1D) is a multifactorial disease involving genetic and environmental factors, including viral infection. We investigated the impact of interferon alpha (IFN-α), a cytokine produced during the immune response to viral infection or the presence of un-edited endogenous double-stranded RNAs, on human β-cell physiology. Intravital microscopy on transplanted human islets using a β-cell-selective reactive oxygen species (ROS) biosensor (RIP1-GRX1-roGFP2), revealed a subset of human β-cells that acutely produce ROS in response to IFN-α. Comparison to Integrated Islet Distribution Program (IIDP) phenotypic data revealed that healthier donors had more ROS accumulating cells. I n vitro IFN-α treatment of human islets similarly elicited a heterogenous increase in superoxide production that originated in the mitochondria. To determine the unique molecular signature predisposing cells to IFN-α stimulated ROS production, we flow sorted human islets treated with IFN-α. RNA sequencing identified genes involved in inflammatory and immune response in the ROS-producing cells. Comparison with single cell RNA-Seq datasets available through the Human Pancreas Analysis Program (HPAP) showed that genes upregulated in ROS-producing cells are enriched in control β-cells rather than T1D donors. Combined, these data suggest that IFN-α stimulates mitochondrial ROS production in healthy human β-cells, potentially predicting a more efficient antiviral response.

A Cure for Type 1 Diabetes: Are We There Yet?

Type 1 diabetes (T1D) affects over 2 million people in the United States and has no known cure. The discovery and first use of insulin in humans 102 years ago marked a revolutionary course of treatment for the disease, and although the formulations and delivery systems have advanced, insulin administration remains the standard of care today. While improved treatment options represent notable progress in T1D management, finding a functional cure for the disease remains the ultimate goal. Approaches to curing T1D have historically focused on blunting the autoimmune response, although sustained effects of immune modulation have proven elusive. Islet transplant therapies have also proven effective, although a lack of available donor tissue and the need for immunosuppression to prevent both host-graft rejection and the autoimmune response have reserved such treatments for those who already require immunosuppressive regimens for other reasons or undergo severe hypoglycemic events in conjunction with hypoglycemic unawareness. With the advent of human stem cell research, the focus has shifted toward generating an abundance of allogeneic, functional beta-like cells that can be transplanted into the patients. Immunoisolation devices have also shown some promise as a method of preventing immune rejection and the autoimmune destruction of transplanted cells. Finally, advances in new immune therapies, if used in the early stages of T1D progression, have proven to delay the onset of diabetes. Stem cell-based therapies are a promising approach to curing T1D. The ongoing clinical trials show some success, although they currently require immunosuppressant agents. Encapsulation devices provide a method of immunoisolation that does not require immunosuppression; however, the devices tested thus far eventually lead to cell death and fibrotic tissue growth. Substantial research efforts are underway to develop new approaches to protect the stem cell-derived beta cells upon transplantation.

Serum and tear autoantibodies from NOD and NOR mice as potential diagnostic indicators of local and systemic inflammation in Sjögren's disease

Background

Sjögren's Disease (SjD) is an autoimmune disease characterized by lymphocytic infiltration of salivary and lacrimal glands (LG). The LG produces the protein-rich aqueous component of tears, and SjD-associated autoimmune dacryoadenitis (AD) may thus alter tear autoantibody composition.

Methods

The presence of tertiary lymphoid structures (TLS) in LG from two murine models of SjD-associated AD, male non-obese diabetic (NOD) and male non-obese insulitis resistant (NOR) mice, were evaluated using immunofluorescence. IgG and IgA reactivity in serum and tears from these models were probed in three studies against a panel of 80-120 autoantigens using autoantibody microarrays relative to serum and tears from healthy male BALB/c mice. Sources of Ig in tears were investigated using scRNA-Seq of the LG (GSE132420). Data were analyzed by R package Limma and Seurat.

Results

Analysis of immunofluorescence in LG sections from both SjD models showed TLS. Only one autoantibody was significantly elevated in tears and serum in both SjD models across all studies. Three autoantibodies were significantly elevated in serum but not in tears in both SjD models across all studies. Conversely, six IgG and thirteen IgA autoantibodies (6 sharing the same autoantigen) were significantly elevated in tears but not serum in both SjD models. Igha and Ighg2b expressing cells were identified in the plasma cell cluster of NOD.H2b LG.

Conclusion

NOD and NOR mice with SjD-associated AD have distinct autoantibody profiles in tears and serum. Tear IgA isotype autoantibodies showed a greater diversity than tear IgG autoantibodies. TLS observed in LG are a likely source of the tear autoantibodies.

Immunopeptidomics for autoimmunity: unlocking the chamber of immune secrets

T cells mediate pathogenesis of several autoimmune disorders by recognizing self-epitopes presented on Major Histocompatibility Complex (MHC) or Human Leukocyte Antigen (HLA) complex. The majority of autoantigens presented to T cells in various autoimmune disorders are not known, which has impeded autoantigen identification. Recent advances in immunopeptidomics have started to unravel the repertoire of antigenic epitopes presented on MHC. In several autoimmune diseases, immunopeptidomics has led to the identification of novel autoantigens and has enhanced our understanding of the mechanisms behind autoimmunity. Especially, immunopeptidomics has provided key evidence to explain the genetic risk posed by HLA alleles. In this review, we shed light on how immunopeptidomics can be leveraged to discover potential autoantigens. We highlight the application of immunopeptidomics in Type 1 Diabetes (T1D), Systemic Lupus Erythematosus (SLE), and Rheumatoid Arthritis (RA). Finally, we highlight the practical considerations of implementing immunopeptidomics successfully and the technical challenges that need to be addressed. Overall, this review will provide an important context for using immunopeptidomics for understanding autoimmunity.

Immune deficiency phenotypes of Il2rg, Rag2 or Il2rg/Rag2 double knockout rats; establishment of human leukemia xenograft models

BACKGROUND

Genetically immunodeficient mice lacking Il2rg and Rag2 genes have been widely utilized in the field of biomedical research. However, immunodeficient rats, which offer the advantage of larger size, have not been as extensively used to date. Recently, Severe Combined Immunodeficiency (SCID) rats were generated using CRISPR/Cas9 system, targeting Il2rg and Rag2 in National BioResource Project in Japan. We imported and investigated more detailed phenotypes of wild-type (WT) Il2rg knockout (KO), Rag2 KO and Il2rg/Rag2 KO rats for 20 weeks.

RESULTS

During experiments, Il2rg KO, Rag2 KO and Il2rg/Rag2 KO rats showed decreased white blood cells and systemic lymphopenia, with reduced CD4+, CD8+ T cells and CD161+ NK cells. Additionally, all KO strains exhibited reduced relative spleen weights, hypoplasia of the germinal center in the white pulp, and atrophy with the disappearance of the boundary between the cortex and medulla in the thymus, compared to WT rats. Furthermore, we established human acute lymphoblastic leukemia xenograft rat model by intravenously injecting 5.0 × 106 cells/kg of NALM6 cells into Il2rg/Rag2 KO rats.

CONCLUSIONS

These findings indicate that Il2rg KO, Rag2 KO, and Il2rg/Rag2 KO rats exhibited SCID phenotypes, suggesting their potential application as immunodeficient animal models for tumor xenograft studies.

12-Lipoxygenase inhibition delays onset of autoimmune diabetes in human gene replacement mice

Type 1 diabetes (T1D) is characterized by the autoimmune destruction of insulin-producing β cells and involves an interplay between β cells and cells of the innate and adaptive immune systems. We investigated the therapeutic potential of targeting 12-lipoxygenase (12-LOX), an enzyme implicated in inflammatory pathways in β cells and macrophages, using a mouse model in which the endogenous mouse Alox15 gene is replaced by the human ALOX12 gene. Our finding demonstrated that VLX-1005, a potent 12-LOX inhibitor, effectively delayed the onset of autoimmune diabetes in human gene replacement non-obese diabetic mice. By spatial proteomics analysis, VLX-1005 treatment resulted in marked reductions in infiltrating T and B cells and macrophages, with accompanying increases in immune checkpoint molecule PD-L1, suggesting a shift toward an immunosuppressive microenvironment. RNA sequencing analysis of isolated islets and polarized proinflammatory macrophages revealed significant alteration of cytokine-responsive pathways and a reduction in IFN response after VLX-1005 treatment. Our studies demonstrated that the ALOX12 human replacement gene mouse provides a platform for the preclinical evaluation of LOX inhibitors and supports VLX-1005 as an inhibitor of human 12-LOX that engages the enzymatic target and alters the inflammatory phenotypes of islets and macrophages to promote the delay of autoimmune diabetes.

UTX Epigenetically Imposes a Cytolytic Effector Program in Autoreactive Stem-like CD8+ T cell Progenitors

Type 1 Diabetes Mellitus (T1D) is an autoimmune disease caused by unremitting immune attack on pancreas insulin-producing beta cells. Persistence of the autoimmune response is mediated by TCF1+ Ly108+ progenitor CD8+ T (Tprog) cells, a stem-like population that gives rise to exhausted effectors with limited cytolytic function in chronic virus infection and cancer. What paradoxically drives Tprog conversion to highly cytolytic effectors in T1D, however, remains unclear. Here, we show that the epigenetic regulator UTX controls diabetogenic CD8+ Tprog differentiation by poising chromatin for transition to a cytolytic effector state. Indeed, deletion of UTX function in T cells impairs conversion of Tprog to autoimmune effectors and protects mice from spontaneous diabetes, as well as an aggressive form of autoimmune diabetes induced by anti-PD1 cancer immunotherapy. Furthermore, short-term treatment with UTX inhibitor GSKJ4 similarly protects from T1D, highlighting the therapeutic potential of targeting UTX-mediated mechanisms to break unremitting autoimmune responses.

Animal models of immune-mediated demyelinating polyneuropathies

Immune-mediated demyelinating polyneuropathies (IMDPs) are rare disorders in which dysregulated adaptive immune responses cause peripheral nerve demyelinating inflammation and axonal injury in susceptible individuals. Despite significant advances in understanding IMDP pathogenesis guided by patient data and representative mammalian models, specific therapies are lacking. Significant knowledge gaps in IMDP pathogenesis still exist, e.g. precise antigen(s) and mechanisms that initially trigger immune system activation and identification of large population disease susceptibility factors. The initial directional cues for antigen-specific effector or autoreactive leukocyte trafficking into peripheral nerves are also unknown. An overview of current animal models, with emphasis on the experimental autoimmune neuritis and spontaneous autoimmune peripheral polyneuropathy models, is provided. Insights on the initial directional cues for peripheral nerve tissue specific autoimmunity using a novel Major Histocompatibility Complex class II conditional knockout mouse strain are also discussed, suggesting an essential research tool to study cell- and time-dependent adaptive immunity in autoimmune diseases.

An IL-2 mutein increases regulatory T cell suppression of dendritic cells via IL-10 and CTLA-4 to promote T cell anergy

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 T cell receptor-dependent gene modules, and high IL-10 and CTLA-4 expression. Increased IL-10 signaling limited surface major histocompatibility complex class II upregulation during conventional dendritic cell (cDC) maturation, while increased CTLA-4-dependent transendocytosis led to the transfer of CD80 and CD86 co-stimulatory 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.

The harmful effect of ankylosing spondylitis on diabetes mellitus: new evidence from the Mendelian randomization analysis

Background

While observational research has highlighted a possible link between ankylosing spondylitis (AS) and type 2 diabetes (T2DM), the quality of evidence remains limited, and the causal relationship is yet to be established. This study aims to explore the causal link between AS and T2DM, as well as its impact on traits related to glucose metabolism.

Method

To infer a causal relationship between AS and various diabetes-related traits, including type 1 diabetes (T1DM), T2DM, blood glucose levels, fasting glucose, glycated hemoglobin, and fasting insulin, we employed Mendelian randomization (MR) analysis. We sourced GWAS summary data for both exposure and outcome variables from the IEU OpenGWAS database, GWAS Catalog, and FinnGen database. To synthesize the results of the MR analyses, we applied meta-analysis techniques using either a fixed or random effects model. For identifying and excluding instrumental variants (IVs) that exhibit horizontal pleiotropy with the outcomes, we utilized the MR-PRESSO method. Sensitivity analyses were conducted using the MR-Egger method, along with Q and I^2 tests, to ensure the robustness of our findings.

Results

Our analysis revealed a significant association between AS and an increased risk of T1DM with an odds ratio (OR) of 1.5754 (95% CI: 1.2935 to 1.9187) and T2DM with an OR of 1.0519 (95% CI: 1.0059 to 1.1001). Additionally, AS was associated with elevated levels of fasting glucose (beta coefficient = 0.0165, 95% CI: 0.0029 to 0.0301) and blood glucose (beta coefficient = 0.0280, 95% CI: 0.0086 to 0.0474), alongside a decrease in fasting insulin levels (beta coefficient = -0.0190, 95% CI: -0.0330 to -0.0050).

Conclusion

Our findings collectively underscore the detrimental impact of AS on the development of diabetes, highlighting the critical influence of autoimmune disorders in diabetes onset. This provides profound insights into the pathogenesis of diabetes from an immunological standpoint.

Small-molecule inhibitors of the CD40-CD40L costimulatory interaction are effective in pancreatic islet transplantation and prevention of type 1 diabetes models

As part of our work to develop small-molecule inhibitors (SMIs) of the CD40-CD40L(CD154) costimulatory protein-protein interaction, here, we describe the ability of two of our most promising SMIs, DRI-C21041 and DRI-C21095, to prolong the survival and function of islet allografts in two murine models of islet transplantation (under the kidney capsule and in the anterior chamber of the eye) and to prevent autoimmune type 1 diabetes (T1D) onset in NOD mice. In both transplant models, a significant portion of islet allografts (50%-80%) remained intact and functional long after terminating treatment, suggesting the possibility of inducing operational immune tolerance via inhibition of the CD40-CD40L axis. SMI-treated mice maintained the structural integrity and function of their islet allografts with concomitant reduction in immune cell infiltration as evidenced by direct longitudinal imaging in situ. Furthermore, in female NODs, three-month SMI treatment reduced the incidence of diabetes from 80% to 60% (DRI-C21041) and 25% (DRI-C21095). These results (i) demonstrate the susceptibility of this TNF superfamily protein-protein interaction to small-molecule inhibition, (ii) confirm the in vivo therapeutic potential of these SMIs of a critical immune checkpoint, and (iii) reaffirm the therapeutic promise of CD40-CD40L blockade in islet transplantation and T1D prevention. Thus, CD40L-targeting SMIs could ultimately lead to alternative immunomodulatory therapeutics for transplant recipients and prevention of autoimmune diseases that are safer, less immunogenic, more controllable (shorter half-lives), and more patient-friendly (i.e., suitable for oral administration, which makes them easier to administer) than corresponding antibody-based interventions.

Polymer scaffolds delineate healthy from diseased states at sites distal from the pancreas in two models of type 1 diabetes

Type 1 diabetes (T1D) prevention is currently limited by the lack of diagnostic tools able to identify disease before autoimmune destruction of the pancreatic β cells. Autoantibody tests are used to predict risk and, in combination with glucose dysregulation indicative of β cell loss, to determine administration of immunotherapies. Our objective was to remotely identify immune changes associated with the disease, and we have employed a subcutaneously implanted microporous poly(e-caprolactone) (PCL) scaffold to function as an immunological niche (IN) in two models of T1D. Biopsy and analysis of the IN enables disease monitoring using transcriptomic changes at a distal site from autoimmune destruction of the pancreas, thereby gaining cellular level information about disease without the need for a biopsy of the native organ. Using this approach, we identified gene signatures that stratify healthy and diseased mice in both an adoptive transfer model and a spontaneous onset model of T1D. The gene signatures identified herein demonstrate the ability of the IN to identify immune activation associated with diabetes across models.

12-Lipoxygenase inhibition delays onset of autoimmune diabetes in human gene replacement mice

Type 1 diabetes (T1D) is characterized by the autoimmune destruction of insulin-producing β cells and involves an interplay between β cells and cells of the innate and adaptive immune systems. We investigated the therapeutic potential of targeting 12-lipoxygenase (12-LOX), an enzyme implicated in inflammatory pathways in β cells and macrophages, using a mouse model in which the endogenous mouse Alox15 gene is replaced by the human ALOX12 gene. Our finding demonstrated that VLX-1005, a potent 12-LOX inhibitor, effectively delayed the onset of autoimmune diabetes in human gene replacement non-obese diabetic mice. By spatial proteomics analysis, VLX-1005 treatment resulted in marked reductions in infiltrating T and B cells and macrophages with accompanying increases in immune checkpoint molecule PD-L1, suggesting a shift towards an immune-suppressive microenvironment. RNA sequencing analysis of isolated islets and polarized proinflammatory macrophages revealed significant alteration of cytokine-responsive pathways and a reduction in interferon response after VLX-1005 treatment. Our studies demonstrated that the ALOX12 human replacement gene mouse provides a platform for the preclinical evaluation of LOX inhibitors and supports VLX-1005 as an inhibitor of human 12-LOX that engages the enzymatic target and alters the inflammatory phenotypes of islets and macrophages to promote the delay of autoimmune diabetes.

Mucosal Addressin Cell Adhesion Molecule-1 Mediates T Cell Migration into Pancreas-Draining Lymph Nodes for Initiation of the Autoimmune Response in Type 1 Diabetes

Type 1 diabetes (T1D) is an autoimmune disease that is caused by autoreactive T cell-mediated destruction of insulin-producing β cells in the pancreatic islets. Although naive autoreactive T cells are initially primed by islet antigens in pancreas-draining lymph nodes (pan-LNs), the adhesion molecules that recruit T cells into pan-LNs are unknown. We show that high endothelial venules in pan-LNs of young nonobese diabetic mice have a unique adhesion molecule profile that includes strong expression of mucosal addressin cell adhesion molecule-1 (MAdCAM-1). Anti-MAdCAM-1 antibody blocked more than 80% of the migration of naive autoreactive CD4+ T cells from blood vessels into pan-LNs. Transient blockade of MAdCAM-1 in young nonobese diabetic mice led to increased numbers of autoreactive regulatory CD4+ T cells in pan-LNs and pancreas and to long-lasting protection from T1D. These results indicate the importance of MAdCAM-1 in the development of T1D and suggest MAdCAM-1 as a potential therapeutic target for treating T1D.

Immunomodulatory Functions of TNF-Related Apoptosis-Inducing Ligand in Type 1 Diabetes

Tumor necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL) is a member of the TNF protein superfamily and was initially identified as a protein capable of inducing apoptosis in cancer cells. In addition, TRAIL can promote pro-survival and proliferation signaling in various cell types. Subsequent studies have demonstrated that TRAIL plays several important roles in immunoregulation, immunosuppression, and immune effector functions. Type 1 diabetes (T1D) is an autoimmune disease characterized by hyperglycemia due to the loss of insulin-producing β-cells, primarily driven by T-cell-mediated pancreatic islet inflammation. Various genetic, epigenetic, and environmental factors, in conjunction with the immune system, contribute to the initiation, development, and progression of T1D. Recent reports have highlighted TRAIL as an important immunomodulatory molecule with protective effects on pancreatic islets. Experimental data suggest that TRAIL protects against T1D by reducing the proliferation of diabetogenic T cells and pancreatic islet inflammation and restoring normoglycemia in animal models. In this review, we aimed to summarize the consequences of TRAIL action in T1D, focusing on and discussing its signaling mechanisms, role in the immune system, and protective effects in T1D.

Working with Miraculous Mice: Mus musculus as a Model Organism

The laboratory mouse has been described as a "miracle" model organism, providing a window by which we may gain an understanding of ourselves. Since the first recorded mouse experiment in 1664, the mouse has become the most used animal model in biomedical research. Mice are ideally suited as a model organism because of their small size, short gestation period, large litter size, and genetic similarity to humans. This article provides a broad overview of the laboratory mouse as a model organism and is intended for undergraduates and those new to working with mice. We delve into the history of the laboratory mouse and outline important terminology to accurately describe research mice. The types of laboratory mice available to researchers are reviewed, including outbred stocks, inbred strains, immunocompromised mice, and genetically engineered mice. The critical role mice have played in advancing knowledge in the areas of oncology, immunology, and pharmacology is highlighted by examining the significant contribution of mice to Nobel Prize winning research. International mouse mutagenesis programs and accurate phenotyping of mouse models are outlined. We also explain important considerations for working with mice, including animal ethics; the welfare principles of replacement, refinement, and reduction; and the choice of mouse model in experimental design. Finally, we present practical advice for maintaining a mouse colony, which involves adequate training of staff, the logistics of mouse housing, monitoring colony health, and breeding strategies. Useful resources for working with mice are also listed. The aim of this overview is to equip the reader with a broad appreciation of the enormous potential and some of the complexities of working with the laboratory mouse in a quest to improve human health. © 2024 The Author(s). Current Protocols published by Wiley Periodicals LLC.

Experimental approaches for induction of diabetes mellitus and assessment of antidiabetic activity: An in vitro and in vivo methodological review

BACKGROUND

Diabetes mellitus poses a global health challenge, driving the need for innovative therapeutic solutions. Experimental methods play a crucial role in evaluating the efficacy of potential antidiabetic drugs, both in vitro and in vivo. Yet concerns about reproducibility persist, necessitating comprehensive reviews.

OBJECTIVES

This review aims to outline experimental approaches for inducing diabetes and evaluating antidiabetic activity, synthesizing data from authoritative sources and academic literature.

METHODS

We conducted a systematic search of prominent databases, including PubMed, ScienceDirect, and Scopus, to identify relevant articles spanning from 1943 to the present. A total of 132 articles were selected for inclusion in this review, focusing on in vitro and in vivo experimental validations of antidiabetic treatments.

RESULTS

Our review highlights the diverse array of experimental methods employed for inducing diabetes mellitus and evaluating antidiabetic interventions. From cell culture assays to animal models, researchers have employed various techniques to study the effectiveness of novel therapeutic agents.

CONCLUSION

This review provides a comprehensive guide to experimental approaches for assessing antidiabetic activity. By synthesizing data from a range of sources, we offer valuable insights into the current methodologies used in diabetes research. Standardizing protocols and enhancing reproducibility are critical for advancing effective antidiabetic treatments.

Differential lipid signaling from CD4+ and CD8+ T cells contributes to type 1 diabetes development

Introduction

We reported that Ca2+-independent phospholipase A2β (iPLA2β)-derived lipids (iDLs) contribute to type 1 diabetes (T1D) onset. As CD4+ and CD8+ T cells are critical in promoting β-cell death, we tested the hypothesis that iDL signaling from these cells participates in T1D development.

Methods

CD4+ and CD8+ T cells from wild-type non-obese diabetic (NOD) and NOD.iPLA2β+/- (NOD.HET) mice were administered in different combinations to immunodeficient NOD.scid.

Results

In mice receiving only NOD T cells, T1D onset was rapid (5 weeks), incidence 100% by 20 weeks, and islets absent. In contrast, onset was delayed 1 week and incidence reduced 40%-50% in mice receiving combinations that included NOD.HET T cells. Consistently, islets from these non-diabetic mice were devoid of infiltrate and contained insulin-positive β-cells. Reduced iPLA2β led to decreased production of proinflammatory lipids from CD4+ T cells including prostaglandins and dihydroxyeicosatrienoic acids (DHETs), products of soluble epoxide hydrolase (sEH), and inhibition of their signaling decreased (by 82%) IFNγ+CD4+ cells abundance. However, only DHETs production was reduced from CD8+ T cells and was accompanied by decreases in sEH and granzyme B.

Discussion

These findings suggest that differential select iDL signaling in CD4+ and CD8+ T cells contributes to T1D development, and that therapeutics targeting such signaling might be considered to counter T1D.

Hyperglycemia in a NOD Mice Model of Type-I Diabetes Aggravates Collagenase-Induced Intracerebral Hemorrhagic Injury

BACKGROUND

Intracerebral hemorrhage (ICH) is a severe type of stroke with high mortality. Persistent hyperglycemia following ICH is linked to deteriorated neurological functions and death. However, the exacerbating effect of hyperglycemia on ICH injury at the molecular level is still unclear. Therefore, this study explores the impact of diabetes on ICH injury using a non-obese diabetic (NOD) mouse model of type I diabetes mellitus.

METHODS

NOD and non-diabetic (non-obese resistant) mice subjected to ICH by intrastriatal injection of collagenase were sacrificed three days following the ICH. Brains were collected for hematoma volume measurement and immunohistochemistry. Neurobehavioral assays were conducted 24 h before ICH and then repeated at 24, 48 and 72 h following ICH.

RESULTS

NOD mice showed increased hematoma volume and impairment in neurological function, as revealed by rotarod and grip strength analyses. Immunohistochemical staining showed reduced glial cell activation, as indicated by decreased GFAP and Iba1 staining. Furthermore, the expression of oxidative/nitrosative stress markers represented by 3-nitrotyrosine and inducible nitric oxide synthase was reduced in the diabetic group.

CONCLUSIONS

Overall, our findings support the notion that hyperglycemia exacerbates ICH injury and worsens neurological function and that the mechanism of injury varies depending on the type of diabetes model used.

Antigen-specific T cell responses in autoimmune diabetes

Autoimmune diabetes is a disease characterized by the selective destruction of insulin-secreting β-cells of the endocrine pancreas by islet-reactive T cells. Autoimmune disease requires a complex interplay between host genetic factors and environmental triggers that promote the activation of such antigen-specific T lymphocyte responses. Given the critical involvement of self-reactive T lymphocyte in diabetes pathogenesis, understanding how these T lymphocyte populations contribute to disease is essential to develop targeted therapeutics. To this end, several key antigenic T lymphocyte epitopes have been identified and studied to understand their contributions to disease with the aim of developing effective treatment approaches for translation to the clinical setting. In this review, we discuss the role of pathogenic islet-specific T lymphocyte responses in autoimmune diabetes, the mechanisms and cell types governing autoantigen presentation, and therapeutic strategies targeting such T lymphocyte responses for the amelioration of disease.

How can we establish animal models of HIV-associated lymphoma?

Human immunodeficiency virus (HIV) infection is strongly associated with a heightened incidence of lymphomas. To mirror the natural course of human HIV infection, animal models have been developed. These models serve as valuable tools to investigate disease pathobiology, assess antiretroviral and immunomodulatory drugs, explore viral reservoirs, and develop eradication strategies. However, there are currently no validated in vivo models of HIV-associated lymphoma (HAL), hampering progress in this crucial domain, and scant attention has been given to developing animal models dedicated to studying HAL, despite their pivotal role in advancing knowledge. This review provides a comprehensive overview of the existing animal models of HAL, which may enhance our understanding of the underlying pathogenesis and approaches for malignancies linked to HIV infection.

Can fecal microbiota transplantations modulate autoimmune responses in type 1 diabetes?

Type 1 diabetes (T1D) is a chronic autoimmune disease targeting insulin-producing pancreatic beta cells. T1D is a multifactorial disease incorporating genetic and environmental factors. In recent years, the advances in high-throughput sequencing have allowed researchers to elucidate the changes in the gut microbiota taxonomy and functional capacity that accompany T1D development. An increasing number of studies have shown a role of the gut microbiota in mediating immune responses in health and disease, including autoimmunity. Fecal microbiota transplantations (FMT) have been largely used in murine models to prove a causal role of the gut microbiome in disease progression and have been shown to be a safe and effective treatment in inflammatory human diseases. In this review, we summarize and discuss recent research regarding the gut microbiota-host interactions in T1D, the current advancement in therapies for T1D, and the usefulness of FMT studies to explore microbiota-host immunity encounters in murine models and to shape the course of human type 1 diabetes.

Untangling the genetics of beta cell dysfunction and death in type 1 diabetes

BACKGROUND

Type 1 diabetes (T1D) is a complex multi-system disease which arises from both environmental and genetic factors, resulting in the destruction of insulin-producing pancreatic beta cells. Over the past two decades, human genetic studies have provided new insight into the etiology of T1D, including an appreciation for the role of beta cells in their own demise.

SCOPE OF REVIEW

Here, we outline models supported by human genetic data for the role of beta cell dysfunction and death in T1D. We highlight the importance of strong evidence linking T1D genetic associations to bona fide candidate genes for mechanistic and therapeutic consideration. To guide rigorous interpretation of genetic associations, we describe molecular profiling approaches, genomic resources, and disease models that may be used to construct variant-to-gene links and to investigate candidate genes and their role in T1D.

MAJOR CONCLUSIONS

We profile advances in understanding the genetic causes of beta cell dysfunction and death at individual T1D risk loci. We discuss how genetic risk prediction models can be used to address disease heterogeneity. Further, we present areas where investment will be critical for the future use of genetics to address open questions in the development of new treatment and prevention strategies for T1D.

Molecular profiling of NOD mouse islets reveals a novel regulator of insulitis onset

Non-obese diabetes (NOD) mice are an established, spontaneous model of type 1 diabetes in which diabetes develops through insulitis. Using next-generation sequencing, coupled with pathway analysis, the molecular fingerprint of early insulitis was mapped in a cohort of mice ranging from 4 to 12 weeks of age. The resulting dynamic timeline revealed an initial decrease in proliferative capacity followed by the emergence of an inflammatory signature between 6 and 8 weeks that increased to a regulatory plateau between 10 and 12 weeks. The inflammatory signature is identified by the activation of central immunogenic factors such as Infg, Il1b, and Tnfa, and activation of canonical inflammatory signaling. Analysis of the regulatory landscape revealed the transcription factor Atf3 as a potential novel modulator of inflammatory signaling in the NOD islets. Furthermore, the Hedgehog signaling pathway correlated with Atf3 regulation, suggesting that the two play a role in regulating islet inflammation; however, further studies are needed to establish the nature of this connection.

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 hinder 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 the 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 that 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 the 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.

Soluble antigen arrays provide increased efficacy and safety over free peptides for tolerogenic immunotherapy

Autoantigen-specific immunotherapy using peptides offers a more targeted approach to treat autoimmune diseases, but clinical implementation has been challenging. 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 used (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. Over time, the peptides induced an IgE-independent anaphylactic reaction, the incidence of which was significantly delayed when peptides were in SAgA form rather than in free form. 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. Immunologic anaphylaxis occurred in NOD mice in a dose-dependent manner but not in C57BL/6 or BALB/c mice; however, its incidence did not correlate with the level of anti-peptide antibodies. We provide evidence that SAgAs significantly improve the efficacy of peptides to induce tolerance and prevent autoimmune diabetes while at the same time reducing their anaphylactogenic potential.

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.