Type 1 diabetes (T1D) arises from T cell-mediated destruction of pancreatic β-cells. However, genetic susceptibility alone cannot account for the increasing incidence and earlier onset of T1D, suggesting a substantial contribution from environmental factors, particularly the gut microbiota. This review synthesises recent human, multiomics and experimental evidence linking gut microbiota dysbiosis and microbial metabolites to β-cell autoimmunity. We focus on two converging mechanisms: (1) metabolite-driven disruption of intestinal barrier integrity and immune regulation, and (2) molecular mimicry between microbial peptides and islet autoantigens that activate autoreactive T cells. Across human cohorts and animal models, T1D-associated dysbiosis features reduced short-chain fatty acid (SCFA)-producing bacteria (e.g., Faecalibacterium, Roseburia) and increased pro-inflammatory taxa (e.g., Bacteroides, Streptococcus spp.). SCFA deficiency compromises Treg induction and gut barrier stability, facilitating antigen translocation. Several gut-derived peptides, such as the Parabacteroides distasonis hprt4-18 peptide, share sequence homology with insulin and other islet antigens, activate insulin-reactive T cells and accelerate diabetes in NOD mice, supporting a role for molecular mimicry. Interventional approaches including FMT, probiotics and prebiotics show promise but remain heterogeneous; their efficacy is highly strain-, timing- and context-dependent and translation from animal studies to humans is still limited. Therapeutically targeting the gut-islet axis, through modulation of microbiota, microbial metabolites or cross-reactive antigens, offers potential for disease prevention or adjunctive treatment. We highlight emerging biomarkers, including MAIT-cell phenotypes, antimicrobial peptide reactivity and microbiome-derived functional signatures, and emphasise the need for stratified clinical trial designs based on age, genotype and baseline microbiota composition to address current variability. The microbiota-metabolite-molecular mimicry axis provides a coherent mechanistic framework linking gut dysbiosis to T1D pathogenesis. Advancing these insights into clinical application will require rigorous, genotype-stratified human studies and standardised, transparent methodological approaches.

ABSTRACT Small non-coding RNAs, such as microRNAs and tRNA-derived fragments, are key regulators of cellular processes, but the functions of small intronic RNAs (sinRNAs), a recently identified RNA class, remain largely unknown. Here, we report that two sinRNAs, sinR-D and sinR-T, are upregulated in pancreatic β-cells of NOD mice, a well-established model of type 1 diabetes. Using in vivo RNA-tagging, we demonstrate that these sinRNAs are packaged into extracellular vesicles released by infiltrating CD4+ T lymphocytes and subsequently delivered to β-cells during the early stages of autoimmune attack. Functional analyses revealed that overexpression of sinR-T has little effect on β-cell viability, whereas sinR-D markedly increases β-cell apoptosis. This finding suggests that the transfer of sinR-D contributes to β-cell destruction and the onset of type 1 diabetes. Furthermore, pull-down experiments with biotinylated sinRNAs identified Ago2, a core component of the RNA-induced silencing complex (RISC), as a binding partner of sinR-D, indicating mechanistic parallels with microRNA-mediated regulation. Collectively, our data uncover a novel role for sinRNAs as extracellularly transferred regulators of β-cell fate, expanding the repertoire of small RNAs implicated in the initiation of type 1 diabetes.

Diabetes is associated with β-cell destruction (Type 1) or functional failure (Type 2). Our research has shown that β-cell failure in Type 2 Diabetes is secondary to the progression of β-cell dedifferentiation. Until recently, it was unclear whether the process was reversible. By analyzing the molecular underpinning of β-cell dedifferentiation, we identified ectopic activation of the enzyme aldehyde dehydrogenase subtype 1A3 (ALDH1A3) as an early marker and effector of the process. Although the signaling pathways by which activation of ALDH1A3 impinges on β-cell function are still to be determined, the enzyme provides a tractable pharmacological target. We have shown that a proprietary, highly potent, and specific ALDH1A3 inhibitor can reverse β-cell dysfunction in animals. Clinical trials of a further version of this compound are being readied. Another area of our interest is the treatment of Type 1 Diabetes by conversion of intestinal epithelial cells into glucose-responsive insulin-producing, β-like cells. We have developed small molecule FoxO1 inhibitors that, when administered orally to diabetic rodents, can lower glycemia and generate insulin-immunoreactive intestinal cells. These cells can also be generated in NOD mice and lead to a restoration of insulin production, demonstrating that they are resistant to autoimmunity. Further preclinical studies are underway to test safety and efficacy of this approach as a Type 1 Diabetes treatment.

Sjögren's disease (SjD) is a group of chronic autoimmune diseases primarily targeting exocrine glands, including the lacrimal glands (LG). Involvement of the lacrimal glands leads to severe dry eye, also known as Sjögren's disease-associated dry eye (SjD-DE). Current, available animal models of SjD are achieved by using autoantigens from salivary gland. This study establishes a novel lacrimal gland-specific autoimmune model that recapitulates key features of SjD-DE, providing a tool for investigating LG-focused mechanisms in SjD. To establish the lacrimal gland-specific Sjögren's model (termed LGSS) model, autoimmune responses were induced in mice using homogenized lacrimal gland proteins. LGSS mice were evaluated at various timepoints after immunization to determine SjD development. SjD phenotype such as tear and saliva secretion, lymphocyte infiltration in the lacrimal and salivary glands and serum autoantibody levels was assessed. Immune cell profiles in the spleen and cervical lymph nodes were evaluated via flow cytometry. In addition, corneal epithelial intactness, goblet cell density, lacrimal gland injury was evaluated to assess lacrimal gland involvement and secondary ocular surface damage. RNA sequencing and gene enrichment analysis of diseased lacrimal glands were performed. LGSS mice demonstrated a reduced tear and saliva secretion, increased lymphocyte infiltration, and elevated autoantibody levels that are similar to common SjD mice. Additionally, the established LGSS mice demonstrated increased populations of Th1 and Th17 cell, along with lacrimal gland and ocular surface damage. RNA sequencing revealed that LGSS mice shared a common genetic profile with NOD mice, the spontaneous SjD model, such as Parp9, Cdkn2c, and Ifi35. Additionally, LGSS mice exhibited several uniquely expressed genes, including metabolism-related genes (Cbs, Dlst, Sardh) and genes associated with cellular processes (Actc1, Tnnc1). The LGSS mice have been shown that successfully replicates several key features of SjD and demonstrates significant lacrimal gland and ocular surface damages, making it a valuable animal model to study SjD-DE.

Type 1 diabetes is a complex autoimmune disorder in which autoreactive CD4⁺ and CD8⁺ T cells destroy pancreatic beta-cells, resulting in insulin deficiency and hyperglycemia. Although genetic susceptibility, particularly certain HLA alleles, contributes to disease risk, not all genetically predisposed individuals develop Type 1 diabetes. Screening first degree relatives (FDRs) for islet autoantibodies (GAD65, IAA, IA-2, ZnT8) helps detect autoimmune activity. However, these serum markers arise only after T-helper cell activation, limiting early intervention opportunities. Since protein antigen recognition by B cells requires T-helper cell assistance through linked recognition, T cell activation precedes B cell activation and autoantibody production. Activation of these T cells leads to shedding of the immune-regulatory (activation) surface protein LAG-3 (Lymphocyte Activation Gene-3 or CD223), generating its soluble form, sLAG-3, that is detectable in circulation. We hypothesized that sLAG-3 may serve as an early biomarker of autoimmune activity preceding islet autoantibody development in type 1 diabetes. Plasma sLAG-3 levels were measured longitudinally in female diabetes-prone NOD mice and analyzed in relation to islet antigen-specific CD4⁺ T cell expansion and diabetes onset. To mechanistically link autoreactive T cell activation to sLAG-3 release. Naive autoreactive C6.6.9 TCR-transgenic (TCR-Tg) CD4⁺ T cells were adoptively transferred into NOD.SCID mice and longitudinal assessment for plasma sLAG-3, beta-cell antigen specific CD4⁺ T cell tetramer profiles, and circulating insulin ( Ins2 ) mRNA to determine ongoing beta-cell stress. In parallel, sLAG-3 levels were analyzed from different human cohorts, including FDRs of individuals with type 1 diabetes, using cross-sectional and longitudinal approaches. In murine models, elevated sLAG-3 correlated with expansion of islet-specific CD4⁺ T cells that preceded hyperglycemia and diabetes onset. In the adoptive transfer model, early increases in sLAG-3 and circulating Ins2 mRNA marked immune activation and emerging beta-cell stress prior to overt diabetes. In our human cohorts, sLAG-3 was detectable in autoantibody-negative and single-autoantibody-positive FDRs, with higher levels observed in progressors compared to non-progressors, and associated with high-risk HLA genotypes. These findings identify sLAG-3 as a candidate biomarker of early T cell activation in type 1 diabetes that may precede islet autoantibody development. Integration of sLAG-3 with antigen-specific T cell and beta-cell stress markers could improve early risk stratification and inform preventive strategies before substantial loss of beta-cell. Prospective longitudinal studies aligned to seroconversion are required to validate sLAG-3 as a surrogate marker of early disease activity. What is already known about this subject?: Before the clinical onset of hyperglycemia, type 1 diabetes is characterized by a prolonged preclinical phase in which autoreactive B and T cells mediate progressive beta-cell destruction.Current risk stratification strategies rely mainly on genetic susceptibility (genomic DNA) and the detection of islet autoantibodies in plasma/serum.Islet autoantibodies arise only after CD4⁺ T cell activation and therefore do not capture the earliest stages of immune dysregulation.Consequently, biomarkers that directly reflect early pathogenic T cell activity prior to, or independent of, seroconversion remain limited and insufficiently validated.What is the key question?: Can plasma sLAG-3 levels, beta-cell antigen-specific CD4⁺ T cell tetramer expression, and circulating Ins2 mRNA serve as very early biomarkers of autoimmune activity in type 1 diabetes and serve to better inform risk stratification, thereby informing preventive intervention strategies for the clinician? What are the new findings?: sLAG-3 increases transiently during early antigen-specific CD4⁺ T cell activation stage, precedes hyperglycemia in mouse models, and is elevated in autoantibody-negative and single-autoantibody-positive first-degree relatives who later progress to type 1 diabetes. sLAG-3 was associated with beta-cell antigen-specific CD4⁺ T cell expansion, assessment of stress induced beta cell Ins2 mRNA release and high-risk HLA genotypes, indicating early autoimmune activation rather than established disease. How might this impact clinical practice in the foreseeable future?: These findings support sLAG-3 as a candidate early biomarker of T cell activation, before or at the earliest stages of islet autoantibody development in some at-risk individuals. Integration of plasma sLAG-3 with beta-cell antigen specific CD4⁺ T cell profiling and insulin mRNA measurements could complement current autoantibody-based screening, improve risk stratification, and enable earlier preventive interventions to preserve beta-cell function in patients at-risk for type 1 diabetes.

Sjögren's disease (SjD), a systemic autoimmune disease, is characterized by exocrine glandular damage and hypofunction. The molecular mechanism of SjD was still unknown. Mendelian analysis was conducted to identify the targets. Clinical characteristics of the serum protein were assessed in a cohort of SjD patients. In NOD mice, the target inhibitor was used to regulate lymphocytic infiltration and salivary secretion, and RNA-seq was conducted. Ferroptosis-related characters and salivary glandular function were evaluated in target-treated animals, as assessed by Fer-1 rescue. As the results indicated, Mendelian analysis identified LGALS9 (the gene encoding Gal9) as a key gene for SjD. In patients, clustering of CRP, ESR, IgG, and RF distinguished two patient groups with distinct Gal9 levels. Elevated Gal9 levels correlated with decreased unstimulated whole saliva flow and higher focus scores. GSE datasets showed that Gal9 is associated with the ferroptosis markers. In the NOD model, Gal9 inhibition reduced FS and IgG levels as well as decreased Th1 and Th17 infiltration. RNA-seq revealed enrichment of ferroptosis-related pathways in SjD. As a regulator of glutathione metabolism, Gal9 promotes ferroptosis through IFN-γ-dependent regulation of ACSL4 and GPX4. Meanwhile, the exacerbation of glandular injury and lipid peroxidation induced by Gal9 was abolished by ferroptosis inhibitor Fer-1. In conclusion, Gal9 promoted ferroptosis-related salivary gland dysfunction in SjD. KEY MESSAGES: Galectin9 (Gal9) acts as a pathogenic mediator in Sjögren's disease (SjD) and a mechanistic amplifier of ferroptosis. Gal9 identified as an upstream inducer of ferroptosis, exacerbated the lymphocytic infiltration and glandular dysfunction in SjD. Inhibition of ferroptosis can restore Gal9-induced salivary gland dysregulation.

Type 1 Diabetes Mellitus (T1D) is an organ-specific autoimmune disease characterized by persistent hyperglycemia due to immune-mediated destruction of pancreatic islet β-cells. Targeting immune cell metabolism has emerged as a promising therapeutic strategy. We investigated whether the fatty acid oxidation (FAO) inhibitor trimetazidine (TMZ), one of only three approved drugs directly targeting cellular metabolism, can restrain autoreactive immunity and delay T1D in non-obese diabetic mice (NOD). TMZ enhanced mitochondrial membrane potential, suppressed FAO, and curtailed activation and proliferation of human CD8+ T cells. In dysglycemic NOD mice, a clinically approved dose of TMZ delayed progression to T1D, reduced mean glycemia, and decreased islet CD4⁺/CD8⁺ infiltration. Single-cell RNA sequencing revealed depletion of FAO-high, stress-responsive cells and mitochondrially active stromal cells, indicating improved pancreatic health. Prolonged exposure induced compensatory upregulation of carnitine-palmitoyl-transferase-1A (CPT1A) in CD8⁺ subsets, counterbalancing early benefits. In summary, TMZ transiently restrains CD8⁺ T cell activity, reduces islet infiltration, and improves pancreatic health. The adaptive upregulation of CPT1A demonstrates a novel evasion mechanism to FAO inhibition and underscores the central role of FAO in sustaining pathogenic T cells. Our work highlights metabolic adaptation as a key determinant of autoimmune progression, validating FAO as a therapeutic target in T1D.

This study successfully developed an oral vaccine for Type 1 Diabetes utilizing recombinant Lactococcus lactis expressing the GAD65 autoantigen. We conducted an in-depth investigation into its protective mechanisms in NOD mice, with a particular focus on its effects on the gut microbiota and metabolome. The administration of the GAD65-L. lactis vaccine resulted in a significant delay in diabetes onset and the preservation of pancreatic function. Our analyses revealed notable alterations in the gut microbial ecosystem, enhancing its diversity and the abundance of beneficial bacteria. Metabolomic profiling indicated time-dependent changes in metabolic pathways, with a marked enrichment of pyrimidine metabolism at 16 weeks and arachidonic acid metabolism at 24 weeks after vaccination by both GAD65-L. lactis and NZ9000-L. lactis. Integrated correlation analysis identified specific microbiota–metabolite interactions, including associations between Ruminiclostridium and lipid species in the GAD65-L. lactis group. These modifications in the microbial community and metabolic landscape were accompanied by enhanced immunoregulatory responses in intestinal LPLs, including expanded Treg populations and suppressed CD8+ T cells, a rising trend in IL-10-producing naive dendritic cells, and increased concentrations of TGF-β.

IntroductionIL-17 is a key cytokine helping preserve the intestinal barrier against infections; however, the T cells that primarily secrete IL-17 (Th17) can promote the development of autoimmunity. In Type 1 diabetes, the role of IL-17 is less well understood, with many studies evaluating the role of IL-17, without considering changes within the intestine. Furthermore, therapeutically targeting IL-12/IL-23 (upstream of IL-17) or IL-17 directly can help preserve insulin-producing beta cells in those newly diagnosed with Type 1 diabetes. Thus, there is a need to better understand how IL-17 may modulate susceptibility to Type 1 diabetes by linking intestinal changes to type 1 diabetes development.MethodsWe studied IL-17-deficient NOD mice to understand the role of IL-17 in mediatingsusceptibility to Type 1 diabetes in vivo and in vitro.ResultsOur study showed that IL-17-deficient NOD mice were protected from autoimmune diabetes, and in vivo adoptive transfer studies showed that both immune and non-immune cells are important for modulating diabetes development. We found significant reductions in both regulatory T cells and inflammatory T-bet-expressing CD8+ T cells, while Type 3 Innate Lymphoid Cells (ILC3s) were expanded. These changes were found to be mediated through altered gut microbiota composition of the IL-17-deficient NOD mice. Finally, we demonstrated that intestinal epithelial cells from IL-17-deficient NOD mice were less able to present autoantigen to autoreactive CD8+ T cells, with reduced proinflammatory cytokine secretion. This effect was specific to IL-17 deficiency, as addition of exogenous IL-17 resulted in improved antigen presentation to autoreactive CD8+ T cells.DiscussionTogether, our data suggest a novel role for IL-17 in modulating epithelial cell function and antigen presentation within the intestinal tissue, resulting in reduced autoantigen-specific T cell responses and enhanced protection from autoimmune diabetes. Better understanding of how targeted IL-17 blockade could be administered to the intestine may help better prevent the development of Type 1 diabetes.

Engineered macroporous gelatin scaffolds enhance lymph node fibroblastic reticular cell identity and enable diabetogenic T cell immunomodulation.

Galectin-3, a β-galactoside–binding lectin, has been implicated in several inflammatory and autoimmune diseases. However, the significance of circulating Galectin-3 in type 1 diabetes (T1D) remains unclear. Here, we report that compared to healthy controls, patients with T1D and their first-degree relatives (FDRs) exhibited significantly increased serum Galectin-3 levels primarily produced and secreted by monocytes/macrophages. Pharmacological inhibition (TD139) as well as knockout of Galectin-3 gene both attenuated Galectin-3–mediated suppression of regulatory T cells (Treg cells) and protected from insulitis and diabetes onset in NOD mice. Mechanistically, Galectin-3 bound to and activated lymphocyte activation gene 3 (LAG3), a receptor expressed on activated T cells, subsequently suppressing the MEK/ERK signaling pathway and thereby hindering Treg cell differentiation and function. In summary, our study identifies Galectin-3 as a potential biomarker for T1D and suggests that TD139 holds promise as a therapeutic candidate for patients with T1D and high serum Galectin-3 levels.

Rapid protein carbonylation and decreased insulin secretion induced by inflammatory oxidative stress compounds.

Tet2 modulates ER stress responses related to β-cell death and autoimmunity in diabetes.

Type 1 diabetes mellitus (T1D) is a chronic disease caused by an unremitting autoimmune attack on pancreatic β cells. This autoimmune chronicity is mediated by stem-like progenitor CD8+ T cells that continually repopulate the pool of β cell–specific cytolytic effectors. Factors governing the conversion of progenitors to effectors, however, remain unclear. T1D has been linked to a chromosomal region (Xp13-p11) that contains the epigenetic regulator UTX, which suggests a key role for UTX in T1D pathogenesis. Here, we show that T cell–specific UTX deletion in NOD mice protects against T1D development. In T cells of NOD mice and patients with T1D, UTX ablation resulted in the accumulation of CD8+ progenitor cells with a concomitant decrease of effector cells, suggesting a key role for UTX in poising progenitors for transition to effectors. Mechanistically, UTX’s role in T1D was independent of its inherent histone demethylase activity but instead relied on binding with transcription factors (TCF1 and STAT3) to coregulate genes important in the maintenance and differentiation of progenitor CD8+ T cells. Together, these findings identify a critical role for UTX in T1D and the UTX:TCF1:STAT3 complex as a therapeutic target for terminating the long-lived autoimmune response.

BackgroundSjögren’s Syndrome (SS) is the second most prevalent autoimmune disease in China without effective therapy. Current evidence indicates safety and effectiveness of CheReCunJin formula (CRCJ) in treating SS. However, the underlying mechanism remains unclear.MethodsUPLC-Q-TOF-MS was applied for compound identification. Multiple components, targets and pathways involved in the treatment of SS with CRCJ were predicted by network pharmacology. Molecular docking was used for preliminary validation. NOD mouse, a classic spontaneous SS model, was used to examine the therapeutic effects on SS of CRCJ. The potential mechanism of CRCJ to mitigate SS was investigated by serum untargeted metabolomics. Validation of key pathway and targets was conducted using flow cytometry, ELISA, immunohistochemistry, Masson staining, and Western blot.Results373 compounds were identified in CRCJ. Through network pharmacology and molecular docking, 15 main components (eg, luteolin 7-O-β-D-glucoside, rutin, 1,4-dicaffeoylquinic acid, anemarsaponin C), 10 core targets (including HSP90AA1, TNF, MMP9, MAPK1, IL6), and the key pathway for CRCJ treating SS, IL-17 signaling pathway, were screened out. In NOD mice, CRCJ demonstrated the ability to improve salivary flow rate and water intake, reduce submandibular gland (SMG) tissue damage, and diminished the levels of IFN-α, IFN-β, IgG in serum. CRCJ modulated metabolic disorders, differentially regulating 63 metabolites and 6 metabolic pathways. Additional validation showed that CRCJ inhibited the Th17 cell activation, downregulated IL-17 signal transduction, and improved ECM degradation in SMG.ConclusionCRCJ protected salivary glands in SS by inhibiting IL-17 signal-mediated inflammatory cascade, an effect likely attributable to key bioactive components such as luteolin 7-O-β-D-glucoside, rutin, 1,4-dicaffeoylquinic acid, and anemarrhenasaponin C. This study provides a foundation for the further development and clinical application of CRCJ for the treatment of SS.

BackgroundAge is a major risk factor for Alzheimer's disease (AD), with brain aging heterogeneity influencing individual susceptibility. Studying variability in aging trajectories due to genetic background can help distinguish normal brain aging from early pathological processes. We have previously showed that the profound impact of genetic variation in modulating phenotypes associated with Alzheimer's disease (AD). In this study, we aim to identify normal brain aging signatures across nine wild‐type strains to capture biological variability often overlooked in single‐strain studies, such as those limited to C57BL/6J.MethodBrain hemispheres from female and male mice (n = 4 per sex) across three age timepoints (4, 12, and 24 months) from nine wild‐type strains (A/J, C57BL/6J, 129S1/SvImJ, NOD/ShiLtJ, NZO/HlLtJ, CAST/EiJ, PWK/PhJ, WSB/EiJ and BALB/cJ) were processed for RNA‐Seq. Strain‐specific aging signatures were identified by comparing 12‐ and 24‐month data to the 4‐month timepoint. Differential expression (DE) and gene set enrichment analyses identified gene modules and pathways associated with brain aging. WGCNA was used to identify common aging signatures across strains. Strain‐specific signatures were aligned with human AD‐related modules using AD biodomains to examine brain aging in the context of AD.ResultAt 12 months, DE genes and enriched pathways were limited and highly variable across strains compared to 4 months. By 24 months, distinct strain‐specific aging signatures emerged, alongside common disruptions in immune response and inflammation. Notably, the magnitude and rate of these disruptions varied across strains, suggesting that baseline genetic differences play a critical role in shaping aging trajectories. Aligning these signatures with Alzheimer's disease (AD) biodomains revealed strain‐specific overlaps with AD‐related processes: NOD mice showed synaptic downregulation, WSB, NZO, and 129 strains exhibited proteostasis disruptions, and CAST mice displayed elevated lipid metabolism.ConclusionThese findings reveal both shared and strain‐specific molecular mechanisms of brain aging, emphasizing genetic influences on neurodegeneration risk. Aging signatures become more pronounced over time, with significant pathway enrichment emerging at 24 months, suggesting an acceleration of aging‐related molecular processes. Studying heterogeneous aging trajectories is crucial for capturing dynamic changes with age while also highlighting baseline genetic differences that shape these processes.

ABSTRACTBackgroundType 1 diabetes mellitus (T1DM) arises from autoimmune destruction of pancreatic β‐cells. Pleomorphic adenoma gene‐like 1 (PLAGL1) overexpression has been linked to β‐cell apoptosis, but molecular mechanisms remain incompletely understood. This study explored whether PLAGL1 exacerbates T1DM by promoting oxidative stress‐induced DNA damage and activating the cGAS/STING inflammatory pathway.MethodsThe mouse β‐cell line NIT‐1 was transfected with PLAGL1 overexpression plasmids or specific siRNA. Mitochondrial and nuclear DNA damage was assessed through comet assays, 8‐OHdG ELISA, and Western blot analysis of key DNA repair proteins, including XRCC1, OGG1, and PARP1. Oxidative stress was evaluated by measuring superoxide dismutase (SOD) activity and the glutathione redox state (GSH/GSSG ratio), while apoptosis was examined via expression levels of BCL2, BAX, and cleaved Caspase‐3. To investigate pathway involvement, pharmacological inhibitors—RU.521 (targeting cGAS) and H‐151 (targeting STING)—were applied. In NOD mice, PLAGL1 overexpression was combined with cGAS/STING inhibition; glucose tolerance was subsequently evaluated, and pancreatic tissue was subjected to histopathological examination.ResultsOverexpression of PLAGL1 triggered substantial mitochondrial and nuclear DNA damage, which was accompanied by elevated oxidative stress and compromised DNA repair. Consequently, cytoplasmic DNA accumulated, leading to activation of the cGAS/STING pathway and subsequent β‐cell apoptosis and functional decline. Treatment with the cGAS inhibitor RU‐521 or the STING inhibitor H‐151 markedly attenuated apoptosis and restored insulin secretion in PLAGL1‐overexpressing NIT‐1 cells. In NOD mice, PLAGL1 overexpression accelerated diabetes progression, whereas inhibition of the cGAS/STING axis preserved β‐cell mass, improved glucose homeostasis, and sustained insulin output. Histological evaluation further confirmed that inhibition of this signaling pathway helped maintain normal islet architecture.ConclusionOur findings demonstrated that PLAGL1 exacerbates β‐cell loss in type 1 diabetes by driving oxidative DNA damage and activating the cGAS/STING signaling cascade. Therapeutic intervention targeting this axis may therefore represent a promising strategy to protect β‐cells and attenuate disease progression.

The C1858T PTPN22 (R620W) variant has been implicated in the pathogenesis of several autoimmune disorders and represents a promising immunotherapeutic target for Type 1 diabetes. We have been implementing a novel immunotherapeutic approach based on the use of lipoplexes that deliver siRNA duplexes. The efficacy and safety of lipoplexes was previously demonstrated in vitro in halting variant expression in the peripheral blood of patients. Preclinical safety and efficacy must be ascertained in vivo in appropriate animal models before clinical investigations can be undertaken, according to regulatory authorities in Europe. In the light of the foregoing, this study aims to verify that lipoplexes against the murine Ptpn22-R619W, equivalent to the human PTPN22-R620W, could be used for animal experimentation. The murine fibroblast cell line L929 was transfected with the PF62-pLentiPtpn22-R619W plasmid. We designed specific siRNA duplexes for the Ptpn22-R619W allele and formulated them into cationic lipoplexes in order to halt variant expression in the transfected L929 cell line. Transfection of fibroblasts expressing R619W using lipoplexes resulted in efficient silencing at 100 pmol siRNA after 48 h post-transfection, reaching higher significant knockdown after 72 h. Lipoplexes efficiently suppress pathogenic Ptpn22 variant expression in vitro, supporting the feasibility of a pre-clinical platform for testing of in vivo lipoplexes in CRISPR-engineered NOD/ShiLtJ mice carrying the R619W mutation.

Mixed hematopoietic chimerism after allogeneic hematopoietic cell transplantation (HCT) promotes tolerance of transplanted donor-matched solid organs, corrects autoimmunity, and could transform therapeutic strategies for autoimmune type 1 diabetes (T1D). However, development of nontoxic bone marrow conditioning protocols is needed to expand clinical use. We developed a chemotherapy-free, nonmyeloablative (NMA) conditioning regimen that achieves mixed chimerism and allograft tolerance across MHC barriers in NOD mice. We obtained durable mixed hematopoietic chimerism in prediabetic NOD mice using anti–CD117 monoclonal antibody, T cell depleting antibodies, JAK1/2 inhibition, and low-dose total body irradiation prior to transplantation of MHC-mismatched B6 hematopoietic cells, preventing diabetes in 100% of chimeric NOD:B6 mice. In overtly diabetic NOD mice, NMA conditioning followed by combined B6 HCT and islet transplantation durably corrected diabetes in 100% of chimeric mice without chronic immunosuppression or graft-versus-host disease (GVHD). Chimeric mice remained immunocompetent, as assessed by blood count recovery and rejection of third-party allogeneic islets. Adoptive transfer studies and analysis of autoreactive T cells confirmed correction of autoimmunity. Analysis of chimeric NOD mice revealed central thymic deletion and peripheral tolerance mechanisms. Thus, with NMA conditioning and cell transplantation, we achieved durable hematopoietic chimerism without GVHD, promoted islet allograft tolerance, and reversed established T1D.

Protection Against Type 1 Diabetes Development in Mice With 4E-BP2 Deletion