Regulatory T cells targeting a pathogenic MHC class II: Insulin peptide epitope postpone spontaneous autoimmune diabetes
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ABSTRACT:
ORGANISM(S): Mus musculus
PROVIDER: GSE238146 | GEO | 2023/07/24
REPOSITORIES: GEO
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Project description:Abstract- The class II region of the Major Histocompatibility locus is the main contributor to the genetic susceptibility to type 1 diabetes (T1D). The loss of an aspartic acid at position 57 of diabetogenic HLA-DQ8 chains supports this association; it influences the recognition of peptides in the context of HLA-DQ8, and I-Ag7 using a mechanism termed the P9 switch. Here, we built register-specific insulin MHC tetramers, Ins12-20 and Ins13-21, to examine anti-insulin CD4 T cell responses during the early pre-diabetic phase of disease in mice. A single cell gene expression analysis and single cell T cell receptor (TCR) sequencing of anti-insulin CD4 T cells performed in 6 and 12-week-old NOD mice, revealed tissue-specific gene expression signatures. TCR signaling and clonal expansion were found only in the islets of Langerhans. and produced either classical Th1 differentiation or an unusual Treg phenotype, independent of TCR usage. The early phase of the anti-insulin response was dominated by cells specific for Ins12-20, the register that supports a P9 switch mode of recognition. The presence of the switch was demonstrated by TCR sequencing, re-expression, mutagenesis, and functional testing of alpha/beta TCR pairs in vitro. The genetic correction of the beta57 mutation resulted in the disappearance of D/E residues in the CDR3beta of anti-Ins12-20 T cells, and inability of cells normally activated by a switch to recognize the Ins9-23 peptide. These results provide the first molecular mechanistic explanation that links the unique MHC class II polymorphism of T1D with the recognition of islet antigens and disease onset.
2019-07-18 | GSE134440 | GEO
Project description:Abstract- The class II region of the Major Histocompatibility locus is the main contributor to the genetic susceptibility to type 1 diabetes (T1D). The loss of an aspartic acid at position 57 of diabetogenic HLA-DQ8 chains supports this association; it influences the recognition of peptides in the context of HLA-DQ8, and I-Ag7 using a mechanism termed the P9 switch. Here, we built register-specific insulin MHC tetramers, Ins12-20 and Ins13-21, to examine anti-insulin CD4 T cell responses during the early pre-diabetic phase of disease in mice. A single cell gene expression analysis and single cell T cell receptor (TCR) sequencing of anti-insulin CD4 T cells performed in 6 and 12-week-old NOD mice, revealed tissue-specific gene expression signatures. TCR signaling and clonal expansion were found only in the islets of Langerhans. and produced either classical Th1 differentiation or an unusual Treg phenotype, independent of TCR usage. The early phase of the anti-insulin response was dominated by cells specific for Ins12-20, the register that supports a P9 switch mode of recognition. The presence of the switch was demonstrated by TCR sequencing, re-expression, mutagenesis, and functional testing of alpha/beta TCR pairs in vitro. The genetic correction of the beta57 mutation resulted in the disappearance of D/E residues in the CDR3beta of anti-Ins12-20 T cells, and inability of cells normally activated by a switch to recognize the Ins9-23 peptide. These results provide the first molecular mechanistic explanation that links the unique MHC class II polymorphism of T1D with the recognition of islet antigens and disease onset.
2019-07-25 | GSE134883 | GEO
Project description:Type 1 diabetes (T1D) is characterized by pancreatic islet infiltration by autoreactive immune cells and a near-total loss of β-cells. Restoration of insulin-producing β-cells coupled with immunomodulation to suppress the autoimmune attack has emerged as a potential approach to counter T1D. Here we report that enhancing β-cell mass in female NOD mice early in life (prior to weaning) results in immunomodulation of T-cells, reduced islet infiltration and lower β-cell apoptosis, that together protect them from developing T1D. We observed that a model exhibiting β-cell hyperplasia on the NOD background (NOD-LIRKO) displayed altered β-cell antigens, and islet transplantation studies showed prolonged graft survival of NOD-LIRKO islets even upon exposure to diabetogenic splenocytes in vivo. Adoptive transfer of splenocytes from the NOD-LIRKOs prevented diabetes development in pre-diabetic NOD mice, while conversely, similar protective outcomes were obtained when NOD-LIRKO splenocytes were adoptively transferred after mixing them with diabetogenic NOD splenocytes in a dose-dependent manner. A significant increase in the splenic CD4+CD25+FoxP3+ regulatory T-cell (Treg) population in the NOD-LIRKO mice was observed to drive the protected phenotype since Treg depletion rendered NOD-LIRKO mice diabetic. The increase in Tregs coupled with a downregulation of key mediators of cellular function, upregulation of apoptosis and activation of TGF-β/SMAD3 signaling pathway in pathogenic T-cells favored reduced ability to kill β-cells. These data provide novel evidence that initiating β-cell proliferation, alone, prior to islet infiltration by immune cells alters the identity of β-cells, decreases pathologic self-reactivity of effector cells and increases Tregs to prevent progression of T1D.
2019-03-29 | GSE128315 | GEO
Project description:Biomarkers capable of monitoring β cell stress during the evolution of type 1 diabetes (T1D) are currently lacking. MicroRNAs (miRNAs) are a class of small non-coding RNAs ~22 nucleotides in length that modulate gene expression by binding to the 3’untranslated region of target mRNAs. Given their stability in biological fluids and enrichment in cell-derived EVs, we hypothesized that miRNAs from human islet and islet-derived EVs could identify β-cell stress/death and be leveraged in T1D biomarker strategies. To test this, human islets were obtained from 10 cadaveric donors (5 male/5 female) and treated with or without cytokines (IL-1β and IFN-γ) for 24 hrs, as an ex vivo model of T1D. Small RNA sequencing was performed and identified 1110 and 890 miRNAs in total and 20 and 14 differentially expressed (DE) miRNAs (fold change≥1.5 and p<0.05) from islets and EVs, respectively. These findings were validated in an independent set of cytokine-treated islets and islet-derived EVs (7M and 5F donors). Interestingly, miRNA expression pattern was strikingly different between male and female donors at baseline and under cytokine stress with < 10% overlap among the DE miRNAs. miR-155-5p and miR-146a-5p were the only two miRNAs that were upregulated in cytokine-treated islets and EVs in both the sexes. Functional enrichment analysis of DE miRNAs identified pathways such as insulin signaling, ER stress and apoptosis. Taken together, these data suggest that miRNA expression patterns change dynamically in both human islets and islet-derived EVs in response to pro-inflammatory cytokine stress. EV miRNAs were largely distinct from those in the islet fraction, suggesting that miRNAs are selectively packaged into EVs in response to extrinsic cues. Finally, these data highlight the importance of considering sex as a biological variable when defining T1D biomarkers.
2023-08-08 | GSE160391 | GEO
Project description:Type 1 diabetes (T1D) results from insulin insufficiency due to the loss or dysfunction of pancreatic beta cells following T cell-mediated autoimmune attack. Currently, the only long-term therapy is daily exogenous insulin replacement. The ideal curative approach is the durable restoration of functional islets via transplantation with or without immunosuppression or immune modulation. To date, the limiting factors impeding realization of this goal is the lack of a cost effective and limitless source of high-quality islets suitable for transplantation and the ability to provide long-term islet graft acceptance without prolonged need for deleterious immunosuppression. Ongoing clinical trials are testing the suitability of islets derived from human induced pluripotent stem cells (iPSC); however, long-term acceptance of these or any other islet graft will require a clinically effective therapeutic strategy to prevent engrafted islet destruction by pre-existing islet-antigen specific T cells. While current immunomodulatory strategies focus on autologous T regulatory (Treg) cell expansion or the use of broad immunosuppression, here we demonstrate in the NOD mouse model for T1D that autologous islet graft acceptance can be achieved by the targeted elimination of (re)-activated islet-reactive CD4+ and CD8+ T effector (Teff) cells in the initial post-transplantation period by using a short-acting, combination therapy that results in the elimination of islet-reactive Teff cells by exacerbation of their natural DNA damage response (DDR) to drive apoptosis while at the same time maintaining endogenous Treg cell function and reducing the effector function of residual islet-reactive T cells.
2024-09-11 | GSE262644 | GEO
Project description:Like humans, the NOD mouse and other diabetes susceptible rat strains, T1D in BB rats is dependent on the major histocompatibility complex (MHC, insulin dependent diabetes mellitus locus 1, Iddm1) located on chromosome 20. In rats this is the HLA-DQB1 homologue RT1-B, specifically the RT1u haplotype. Our studies employ congenic derivatives of the BB rat, the DRlyp/lyp and DR+/+ strains, which differ only by the 2 Mb lyp (lymphopenia, Iddm2) region on chromosome 4. TID in the lymphopenic DRlyp/lyp rat is spontaneous and onset occurs in 100% of animals during adolescence (65.3+/-6.3 days) due to a recessive mutation within GIMAP5 (GTPase, IMAP family member 5). Gimap5 is a mitochondrial GTP-binding protein necessary for post-thymic T cell survival. The spontaneously diabetic phenotype observed in DRlyp/lyp rats is thought to be elicited through deficiency in CD4+CD25+ TREG cells as T1D in lymphopenic BB rats can be rescued through adoptive transfer of this population. Genetic variation in GIMAP5 has been associated with the development of protein-tyrosine phosphatase-2 (IA-2) autoantibodies in human T1D [28] and is significantly associated with systemic lupus erythematosus (SLE). The non-lymphopenic DR+/+ strain possesses wild-type GIMAP5 alleles and does not develop spontaneous T1D, however, T1D is inducible through administration of lymphotoxic anti-RT6 monoclonal antibody and immune activating polyinosinic polycytidylic acid (poly I:C; a ligand of toll-like receptor 3), or through viral depletion of CD4+CD25+ regulatory T (TREG) cells. Such treatments do not induce T1D in the related Wistar-Furth (WF) rats and suggest the presence of an underlying diabetic predisposition in BB rats that is phenotypically manifested upon loss of immune regulation. DRlyp/lyp and DR+/+ rats possess characteristics that make them ideal for the identification of pathways relevant to the development of T1D since they possess absolute or conditional susceptibility to T1D. The Gimap-/- Iddm2 locus conveys upon DRlyp/lyp rats a deficiency in immune regulatory capacity and the spontaneous T1D phenotype. Consistent with the concept that autoimmunity involves both a lack of self-tolerance as well as target organ-specific factors, we have discovered that DRlyp/lyp and DR+/+ (BB) rats share an islet specific stress. This is reflected by the expression of immune mediators, including the chemokine eotaxin that recruits eosinophils, certain T cell subsets, dendritic cells, and mast cells, by islet β cells early in life, before infiltration of immune cells into the islet (insulitis). While BB and WF rats share Iddm1 (RT1u/u MHC), islet eotaxin expression in not observed in WF islets and thus is associated with the T1D susceptibility of BB rats. Further supporting the hypothesis that additional genetic factors, perhaps those working at the level of the pancreatic β cell, are necessary for the development of T1D are the observations that 1) The generation Fischer 344 (F344) rats either homozygous for Gimap5-/- or homozygous for both RT1u/u and Gimap5-/- fail to develop T1D; and 2) genetic crosses between BB rats and non diabetic strains have identified numerous Iddm loci independent of Iddm1 and Iddm2. In this study, using islet gene expression profiling, direct serum-level measurement, quantitative real-time PCR and targeted histological follow-up, we investigate pancreatic islet gene expression in BB rat at 5 weeks (+/-5 days) which is prior to insulitis in DRlyp/lyp rats. We compare DR+/+, JB++, JBlyp/lyp and DRlyp/lyp islet activity to that of WF and F344 rats to investigate any potential for reduction in capability to deal with oxidative stress in BB rats compared to non-BB and whether any differences in that capability map to known Iddm regions.
2010-02-21 | E-GEOD-20214 | biostudies-arrayexpress
Project description:Many patients with type 1 diabetes (T1D) have residual beta cells producing small amounts of C-peptide long after disease onset, but develop an inadequate glucagon response to hypoglycemia following T1D diagnosis. The features of these residual beta cells and alpha cells persisting in the islet endocrine compartment are largely unknown due to difficulty of comprehensive investigation. By studying the T1D pancreas and isolated islets, we show that remnant beta cells appeared to maintain several aspects of regulated insulin secretion. However, the function of T1D alpha cells was markedly reduced and these cells had alterations in transcription factors constituting and alpha and beta cell identity. In the native pancreas and after placing the T1D islets into a non-autoimmune, normoglycemic in vivo environment, there was no evidence of alpha-to-beta cell conversion. These results suggest a new explanation for the disordered T1D counterregulatory glucagon response to hypoglycemia.
2017-12-12 | GSE106148 | GEO
Project description:Assessing the self-peptides presented by susceptible major histocompatibility complex (MHC) molecules is crucial for evaluating the pathogenesis and therapeutics of tissue-specific autoimmune diseases. However, direct examination of such MHC-bound peptides displayed in the target organ remains largely impractical. Here, we demonstrate that the blood leukocytes from non-obese diabetic (NOD) mice presented peptide epitopes to autoreactive CD4 T cells. These peptides were bound to the autoimmune class II MHC molecule, I-Ag7, and originated from insulin B-chain and C-peptide. The presentation required a glucose challenge, which stimulated the release of insulin peptides from pancreatic islets. The circulating leukocytes, especially the B cells, promptly captured and presented these peptides. Although canonical intracellular processing of insulin was involved in the presentation, extracellular binding of catabolized insulin products to I-Ag7 gave rise to a unique pathogenic epitope. Administration of monoclonal antibodies recognizing insulin B-chain abolished the presentation and diminished diabetes incidence. Mass spectrometry analysis of the leukocyte MHC-II peptidomes revealed a series of beta cell derived peptides, with identical sequences to those previously in the islet MHC-II peptidome. Thus, the WBC peptidome echoes that found in islets and serves to identify immunogenic peptides in an otherwise inaccessible tissue.
2021-03-26 | PXD024400 | Pride
Project description:The IL-22RA1 receptor is highly expressed in the pancreas, and exogenous IL-22 has been shown to reduce endoplasmic reticulum and oxidative stress in human pancreatic islets and promote secretion of high-quality insulin from beta-cells. However, the endogenous role of IL-22RA1 signaling on these cells remains unclear. Here, we show that antibody neutralisation of IL-22RA1 in cultured human islets leads to impaired insulin quality and increased cellular stress. Through the generation of mice lacking IL-22ra1 specifically on pancreatic alpha- or beta-cells, we demonstrate that ablation of murine beta-cell IL-22ra1 leads to similar decreases in insulin secretion, quality and islet regeneration, whilst increasing islet cellular stress, inflammation and MHC II expression. These changes in insulin secretion led to impaired glucose tolerance, a finding more pronounced in female animals compared to males. Our findings attribute a regulatory role for endogenous pancreatic beta-cell IL-22ra1 in insulin secretion, islet regeneration, inflammation/cellular stress and appropriate systemic metabolic regulation.
2024-04-16 | GSE262867 | GEO
Project description:Pancreatic islet transplantation as a cure for type 1 diabetes (T1D) cannot be scaled up due to a scarcity of human pancreas donors. In vitro expansion of beta cells from mature human pancreatic islets provides an alternative source of insulin-producing cells. The exact nature of the expanded cells produced by diverse expansion protocols, and their potential for differentiation into functional beta cells, remain elusive. We performed a large-scale meta-analysis of gene expression in human pancreatic islet cells, which were processed using three different previously described protocols for expansion and attempted re-differentiation. All three expansion protocols induced dramatic changes in the expression profiles of pancreatic islets; many of these changes are shared among the three protocols. Attempts at re-differentiation of expanded cells induce a limited number of gene expression changes. Nevertheless, these fail to restore a pancreatic islet-like gene expression pattern. Comparison with a collection of public microarray datasets confirmed that expanded cells are highly comparable to mesenchymal stem cells. Genes induced in expanded cells are also enriched for targets of transcription factors important for pluripotency induction. The present data increases our understanding of the active pathways in expanded and re-differentiated islets. Knowledge of the mesenchymal stem cell potential may help development of drug therapeutics to restore beta cell mass in T1D patients. Experiment Overall Design: In this study, we have tested three different protocols to expand human pancreatic islets in monolayer and after attempted maneuvers to re-differentiate the expanded cells back to islets. We have characterized the resulting cells in detail by performing microarray analyses with fresh pancreatic islets, expanded islet cells and re-differentiated cells. Genes modified by either of three protocols have 70 to 80% overlap with the genes changed by the other two protocols. Although there are promising changes in the right direction, none of the three protocols could achieve a return to a functional islet state. The expanded cells highly resemble Mesenchymal Stem Cells (MSC), and similar gene regulatory networks seem to be active in both cell types. On the other hand, the expanded islet cells are different from MSC in that they seem to retain activity of some islet gene modules. The current results highlight the importance of designing new strategies that take into account the MSC potential of expanded cells.
2009-08-07 | E-GEOD-15543 | biostudies-arrayexpress