scholarly journals Presumption of guilt for T cells in type 1 diabetes: lead culprits or partners in crime depending on age of onset?

Diabetologia ◽  
2020 ◽  
Vol 64 (1) ◽  
pp. 15-25 ◽  
Author(s):  
Alexia Carré ◽  
Sarah J. Richardson ◽  
Etienne Larger ◽  
Roberto Mallone
Keyword(s):  
T Cells ◽  
Type 1 Diabetes ◽  
T Cell ◽  
Beta Cells ◽  
Disease Onset ◽  
Strong Support ◽  
Islet Autoimmunity ◽  
Relative Role ◽  
Age Related

AbstractAvailable evidence provides arguments both for and against a primary pathogenic role for T cells in human type 1 diabetes. Genetic susceptibility linked to HLA Class II lends strong support. Histopathology documents HLA Class I hyperexpression and islet infiltrates dominated by CD8+ T cells. While both hallmarks are near absent in autoantibody-positive donors, the variable insulitis and residual beta cells of recent-onset donors suggests the existence of a younger-onset endotype with more aggressive autoimmunity and an older-onset endotype with more vulnerable beta cells. Functional arguments from ex vivo and in vitro human studies and in vivo ‘humanised’ mouse models are instead neutral or against a T cell role. Clinical support is provided by the appearance of islet autoantibodies before disease onset. The faster C-peptide loss and superior benefits of immunotherapies in individuals with younger-onset type 1 diabetes reinforce the view of age-related endotypes. Clarifying the relative role of T cells will require technical advances in the identification of their target antigens, in their detection and phenotyping in the blood and pancreas, and in the study of the T cell/beta cell crosstalk. Critical steps toward this goal include the understanding of the link with environmental triggers, the description of T cell changes along the natural history of disease, and their relationship with age and the ‘benign’ islet autoimmunity of healthy individuals.

scholarly journals An HLA-Transgenic Mouse Model of Type 1 Diabetes That Incorporates the Reduced but Not Abolished Thymic Insulin Expression Seen in Patients

2016 ◽  
Vol 2016 ◽  
pp. 1-8 ◽  
Author(s):  
Jeffrey Babad ◽  
Riyasat Ali ◽  
Jennifer Schloss ◽  
Teresa P. DiLorenzo
Keyword(s):  
Type 1 Diabetes ◽  
T Cell ◽  
Beta Cells ◽  
Immune Cell ◽  
Regulatory Region ◽  
Islet Autoimmunity ◽  
Positive Type ◽  
Insulin Expression ◽  
Pancreatic Islet Beta Cells

Type 1 diabetes (T1D) is an autoimmune disease characterized by T cell-mediated destruction of the pancreatic islet beta cells. Multiple genetic loci contribute to disease susceptibility in humans, with the most responsible locus being the major histocompatibility complex (MHC). Certain MHC alleles are predisposing, including the common HLA-A∗02:01. After the MHC, the locus conferring the strongest susceptibility to T1D is the regulatory region of the insulin gene, and alleles associated with reduced thymic insulin expression are predisposing. Mice express two insulin genes,Ins1andIns2. While both are expressed in beta cells, onlyIns2is expressed in the thymus. We have developed an HLA-A∗02:01-transgenic NOD-based T1D model that is heterozygous for a functionalIns2gene. These mice exhibit reduced thymic insulin expression and accelerated disease in both genders. Immune cell populations are not grossly altered, and the mice exhibit typical signs of islet autoimmunity, including CD8 T cell responses to beta cell peptides also targeted in HLA-A∗02:01-positive type 1 diabetes patients. This model should find utility as a tool to uncover the mechanisms underlying the association between reduced thymic insulin expression and T1D in humans and aid in preclinical studies to evaluate insulin-targeted immunotherapies for the disease.

scholarly journals A miRNA181a/NFAT5 axis links impaired T cell tolerance induction with autoimmune type 1 diabetes

2018 ◽  
Vol 10 (422) ◽  
pp. eaag1782 ◽  
Author(s):  
Isabelle Serr ◽  
Martin G. Scherm ◽  
Adam M. Zahm ◽  
Jonathan Schug ◽  
Victoria K. Flynn ◽  
...  
Keyword(s):  
T Cells ◽  
Type 1 Diabetes ◽  
T Cell ◽  
Early Stage ◽  
Tolerance Induction ◽  
Islet Autoimmunity ◽  
Activated T Cells

Molecular checkpoints that trigger the onset of islet autoimmunity or progression to human type 1 diabetes (T1D) are incompletely understood. Using T cells from children at an early stage of islet autoimmunity without clinical T1D, we find that a microRNA181a (miRNA181a)–mediated increase in signal strength of stimulation and costimulation links nuclear factor of activated T cells 5 (NFAT5) with impaired tolerance induction and autoimmune activation. We show that enhancing miRNA181a activity increases NFAT5 expression while inhibiting FOXP3+ regulatory T cell (Treg) induction in vitro. Accordingly, Treg induction is improved using T cells from NFAT5 knockout (NFAT5ko) animals, whereas altering miRNA181a activity does not affect Treg induction in NFAT5ko T cells. Moreover, high costimulatory signals result in phosphoinositide 3-kinase (PI3K)–mediated NFAT5, which interferes with FoxP3+ Treg induction. Blocking miRNA181a or NFAT5 increases Treg induction in murine and humanized models and reduces murine islet autoimmunity in vivo. These findings suggest targeting miRNA181a and/or NFAT5 signaling for the development of innovative personalized medicines to limit islet autoimmunity.

Regeneration of insulin-producing [beta]-cells during recovery from disease: a cure for Type 1 Diabetes

2018 ◽  
Author(s):  
◽  
Tobechukwu Kenneth Ukah
Keyword(s):  
T Cells ◽  
Type 1 Diabetes ◽  
T Cell ◽  
Combination Therapy ◽  
Beta Cells ◽  
Th17 Cells ◽  
Nod Mice ◽  
I Cells

[ACCESS RESTRICTED TO THE UNIVERSITY OF MISSOURI AT AUTHOR'S REQUEST.] Type 1 diabetes (T1D) is a chronic disease condition characterized by destruction of the insulin-producing [beta]-cells by self-reactive lymphocytes of the immune system. While some immunotherapeutic approaches against T1D directly target and modulate diabetogenic specific T cells or the entire T cell repertoire, other efforts utilize antigen presenting cells or T cell-regulating molecules to control the T cells. In chapter II, we set out to determine the role of regulatory cytokines, IL-4 and IL-13 in T1D progression. IL-4 and IL-13 are widely reported as anti-inflammatory cytokines, and both can signal via the IL-4R[alpha]/IL-13R[alpha]1 heteroreceptor (HR). To determine the role of these cytokines in T1D development, we generated NOD mice in which the IL-13R[alpha]1 arm of the HR is deleted, thereby rendering the HR nonfunctional. Surprisingly, the findings indicate that NOD mice lacking the HR (13R-/-) display resistance to T1D as the rise in blood glucose level (BGL) and islet inflammation were significantly delayed in these HR-deficient relative to HR-sufficient (13R+/+) mice. In fact, the frequency and spleen-to-pancreas dynamics of both Th1 and Th17 cells were affected in 13R-/- mice. This outcome is likely due to an increase in the frequency of mTGF[beta][subscript +]Foxp3[subscript int] regulatory T cells and persistence of CD206[subscript +] macrophage in the pancreas as both types of cells confer resistance to T1D upon transfer to 13R+/+ mice. These findings reveal new insights as to the role environmental IL-4/IL-13 and the HR play in peripheral tolerance and the development of T1D. In chapter III, we investigate the source of newly formed β-cells during recovery from overt T1D under a combination therapy that involves an immunoglobulin chimera, Ig-GAD2 and bone marrow cells transfer. This combination therapy proved effective in driving immune modulation of diabetogenic-specific T cells and repair of the islet vasculature leading to the formation of new endogenous [beta]-cells that were able to thrive and restore long-lasting normoglycemia. Our new findings reveal and suggest that the combination therapy leads to the formation of healthy islets by inducing division of residual β-cells and differentiation of precursor cells. Furthermore, while the pancreas is cleared of immune infiltration during recovery from disease, both the lymph nodes and spleen displayed a significant reduction in Th17 cells, and the disease did not rebound. These circumstances are relevant to humans as intervention could be made at early as well as late stages after diagnosis. Overall, these results provide insights on future immunotherapeutic measures of T1D using regulatory cytokines or intervention with an antigen-specific therapy.

scholarly journals HLA-B*39:06 Efficiently Mediates Type 1 Diabetes in a Mouse Model Incorporating Reduced Thymic Insulin Expression1

2018 ◽  
Author(s):  
Jennifer Schloss ◽  
Riyasat Ali ◽  
Jeremy J. Racine ◽  
Harold D. Chapman ◽  
David V. Serreze ◽  
...  
Keyword(s):  
T Cells ◽  
Type 1 Diabetes ◽  
T Cell ◽  
Mouse Model ◽  
Disease Onset ◽  
Cell Subset ◽  
Class I ◽  
Class I Mhc ◽  
Insulin Expression

ABSTRACTType 1 diabetes (T1D) is characterized by T cell-mediated destruction of the insulin-producing βcells of the pancreatic islets. Among the loci associated with T1D risk, those most predisposing are found in the MHC region. HLA-B*39:06 is the most predisposing class I MHC allele and is associated with an early age of onset. To establish an NOD mouse model for the study of HLA-B*39:06, we expressed it in the absence of murine class I MHC. HLA-B*39:06 was able to mediate the development of CD8 T cells, support lymphocytic infiltration of the islets, and confer T1D susceptibility. Because reduced thymic insulin expression is associated with increased T1D risk in patients, we incorporated this in our model as well, finding that HLA-B*39:06-transgenic NOD mice with reduced thymic insulin expression have an earlier age of disease onset and a higher overall prevalence as compared to littermates with typical thymic insulin expression. This was despite virtually indistinguishable blood insulin levels, T cell subset percentages, and TCR Vβ family usage, indicating that reduced thymic insulin expression does not impact T cell development on a global scale. Rather, we propose that it allows the thymic escape of insulin-reactive HLA-B*39:06-restricted T cells which participate in β cell destruction. We also found that in mice expressing either HLA-B*39:06 or HLA-A*02:01 in the absence of murine class I MHC, HLA transgene identity alters TCR Vβ usage, which may contribute to varying diabetogenic CD8 T cell repertoires in the presence of different HLA class I alleles.

scholarly journals An Age-Related Exponential Decline in the Risk of Multiple Islet Autoantibody Seroconversion During Childhood

2021 ◽  
Author(s):  
Ezio Bonifacio ◽  
Andreas Weiß ◽  
Christiane Winkler ◽  
Markus Hippich ◽  
Marian J. Rewers ◽  
...  
Keyword(s):  
Type 1 Diabetes ◽  
Confidence Interval ◽  
Islet Autoantibodies ◽  
Islet Autoimmunity ◽  
Islet Autoantibody ◽  
Age Related ◽  
At Risk Children ◽  
Exponential Decline ◽  
Design And Methods

<b>Objective</b>. Islet autoimmunity develops prior to clinical type 1 diabetes and includes multiple and single autoantibody phenotypes. The objective was to determine age-related risks of islet autoantibodies that reflect etiology and improve screening for pre-symptomatic type 1 diabetes. <p><b>Research Design and Methods</b>. The Environmental Determinants of Diabetes in the Young study prospectively followed 8,556 genetically at-risk children at 3–6-month intervals from birth for the development of islet autoantibodies and type 1 diabetes. The age-related change in the risk of developing islet autoantibodies was determined using landmark and regression models. </p> <p><b>Results</b>. The 5-year risk of developing multiple islet autoantibodies was 4.3% (95% confidence interval, 3.8–4.7) at 7.5 months of age and declined to 1.1% (95% confidence interval, 0.8–1.3) at a landmark age of 6.25 years (<i>P</i><0.0001). Risk decline was slight or absent in single insulin- and GAD-autoantibody phenotypes. The influence of sex, <i>HLA</i> and other susceptibility genes on risk subsided with increasing age and was abrogated by age six years. Highest sensitivity and positive predictive value of multiple islet autoantibody phenotypes for type 1 diabetes was achieved by autoantibody screening at 2 years and again at 5–7 years of age. </p> <p><b>Conclusions</b>. The risk of developing islet autoimmunity declines exponentially with age and the influence of major genetic factors on this risk is limited to the first few years of life. </p>

scholarly journals Proinsulin-Reactive CD4 T Cells in the Islets of Type 1 Diabetes Organ Donors

2021 ◽  
Vol 12 ◽  
Author(s):  
Laurie G. Landry ◽  
Amanda M. Anderson ◽  
Holger A. Russ ◽  
Liping Yu ◽  
Sally C. Kent ◽  
...  
Keyword(s):  
T Cells ◽  
Type 1 Diabetes ◽  
T Cell ◽  
Cd4 T Cells ◽  
Pancreatic Beta Cells ◽  
Hot Spot ◽  
Cell Receptor ◽  
Organ Donors ◽  
Hla Dq

Proinsulin is an abundant protein that is selectively expressed by pancreatic beta cells and has been a focus for development of antigen-specific immunotherapies for type 1 diabetes (T1D). In this study, we sought to comprehensively evaluate reactivity to preproinsulin by CD4 T cells originally isolated from pancreatic islets of organ donors having T1D. We analyzed 187 T cell receptor (TCR) clonotypes expressed by CD4 T cells obtained from six T1D donors and determined their response to 99 truncated preproinsulin peptide pools, in the presence of autologous B cells. We identified 14 TCR clonotypes from four out of the six donors that responded to preproinsulin peptides. Epitopes were found across all of proinsulin (insulin B-chain, C-peptide, and A-chain) including four hot spot regions containing peptides commonly targeted by TCR clonotypes derived from multiple T1D donors. Of importance, these hot spots overlap with peptide regions to which CD4 T cell responses have previously been detected in the peripheral blood of T1D patients. The 14 TCR clonotypes recognized proinsulin peptides presented by various HLA class II molecules, but there was a trend for dominant restriction with HLA-DQ, especially T1D risk alleles DQ8, DQ2, and DQ8-trans. The characteristics of the tri-molecular complex including proinsulin peptide, HLA-DQ molecule, and TCR derived from CD4 T cells in islets, provides an essential basis for developing antigen-specific biomarkers as well as immunotherapies.

scholarly journals Increased islet antigen–specific regulatory and effector CD4+ T cells in healthy individuals with the type 1 diabetes–protective haplotype

2020 ◽  
Vol 5 (44) ◽  
pp. eaax8767 ◽  
Author(s):  
Xiaomin Wen ◽  
Junbao Yang ◽  
Eddie James ◽  
I-Ting Chow ◽  
Helena Reijonen ◽  
...  
Keyword(s):  
T Cells ◽  
Type 1 Diabetes ◽  
T Cell ◽  
Regulatory T Cells ◽  
Interleukin 4 ◽  
Specific Class ◽  
Protective Haplotype ◽  
Specific Effector ◽  
Islet Antigen

The DRB1*15:01-DQB1*06:02 (DR1501-DQ6) haplotype is linked to dominant protection from type 1 diabetes, but the cellular mechanism for this association is unclear. To address this question, we identified multiple DR1501- and DQ6-restricted glutamate decarboxylase 65 (GAD65) and islet-specific glucose-6-phosphatase catalytic subunit–related protein (IGRP)–specific T cell epitopes. Three of the DR1501/DQ6-restricted epitopes identified were previously reported to be restricted by DRB1*04:01/DRB1*03:01/DQB1*03:02. We also used specific class II tetramer reagents to assess T cell frequencies. Our results indicated that GAD65- and IGRP-specific effector and CD25+CD127−FOXP3+ regulatory CD4+ T cells were present at higher frequencies in individuals with the protective haplotype than those with susceptible or neutral haplotypes. We further confirmed higher frequencies of islet antigen–specific effector and regulatory CD4+ T cells in DR1501-DQ6 individuals through a CD154/CD137 up-regulation assay. DR1501-restricted effector T cells were capable of producing interferon-γ (IFN-γ) and interleukin-4 (IL-4) but were more likely to produce IL-10 compared with effectors from individuals with susceptible haplotypes. To evaluate their capacity for antigen-specific regulatory activity, we cloned GAD65 and IGRP epitope–specific regulatory T cells. We showed that these regulatory T cells suppressed DR1501-restricted GAD65- and IGRP-specific effectors and DQB1*03:02-restricted GAD65-specific effectors in an antigen-specific fashion. In total, these results suggest that the protective DR1501-DQ6 haplotype confers protection through increased frequencies of islet-specific IL-10–producing T effectors and CD25+CD127−FOXP3+ regulatory T cells.

scholarly journals Position β57 of I-Ag7 controls early anti-insulin responses in NOD mice, linking an MHC susceptibility allele to type 1 diabetes onset

2019 ◽  
Vol 4 (38) ◽  
pp. eaaw6329 ◽  
Author(s):  
Louis Gioia ◽  
Marie Holt ◽  
Anne Costanzo ◽  
Siddhartha Sharma ◽  
Brian Abe ◽  
...  
Keyword(s):  
T Cells ◽  
Type 1 Diabetes ◽  
Disease Onset ◽  
Insulin Response ◽  
Nod Mice ◽  
Class Ii ◽  
Single Amino Acid ◽  
Specific Gene ◽  
Single Amino Acid Change

The class II region of the major histocompatibility complex (MHC) 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-DQβ chains supports this association; this single amino acid change influences how TCRs recognize peptides in the context of HLA-DQ8 and I-Ag7 using a mechanism termed the P9 switch. Here, we built register-specific insulin peptide MHC tetramers to examine CD4+ T cell responses to Ins12–20 and Ins13–21 peptides during the early prediabetic phase of disease in nonobese diabetic (NOD) mice. A single-cell analysis 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 T cells specific for Ins12–20, the register that supports a P9 switch mode of recognition. The presence of the P9 switch was demonstrated by TCR sequencing, reexpression, mutagenesis, and functional testing of TCRαβ pairs in vitro. Genetic correction of the I-Aβ57 mutation in NOD mice resulted in the disappearance of D/E residues in the CDR3β of anti-Ins12–20 T cells. These results provide a mechanistic molecular explanation that links the characteristic MHC class II polymorphism of T1D with the recognition of islet autoantigens and disease onset.

scholarly journals Children with type 1 diabetes of early age at onset – immune and metabolic phenotypes

2019 ◽  
Vol 32 (9) ◽  
pp. 935-941
Author(s):  
Madalena Sales Luis ◽  
Margarida Alcafache ◽  
Sara Ferreira ◽  
Ana Laura Fitas ◽  
Joana Simões Pereira ◽  
...  
Keyword(s):  
Type 1 Diabetes ◽  
Age At Onset ◽  
Disease Onset ◽  
Inverse Correlation ◽  
Early Age ◽  
Insulin Requirements ◽  
Age Related ◽  
One Year ◽  
Immune Imbalance

Abstract Objectives We aimed to evaluate children with type 1 diabetes (T1D) with early age at onset (EAO) for clinical, immune and metabolic features in order to identify age-related disease phenotypes. Methods Comparative study of two groups of T1D children: EAO (≤5 years) and later age at onset (LAO; >5 years), regarding the presence of other autoimmune (AI) diseases, diabetes ketoacidosis and immunologic profile at onset and metabolic data 1 year after diagnosis. Statistical analysis was performed with significance set for p < 0.05. Results The study included 137 children (EAO = 52, mean age 3.6 ± 1.5 [mean ± standard deviation (SD)] and LAO = 85, mean age 10.4 ± 2.9). EAO was more associated with concomitant AI diseases (p = 0.032). Despite no differences in disease onset, EAO presented with lower C-peptide levels (p = 0.01) and higher absolute lymphocyte number (p < 0.0001), with an inverse correlation between these two variables (p = 0.028). Additionally, the EAO group had a higher frequency of serum detection of three antibodies (Abs) (p = 0.0008), specifically insulin Abs (p = 0.0001). One year after diagnosis, EAO had higher total daily insulin (TDI) dose (p = 0.008), despite similar hemoglobin A1c (HbA1c). Conclusions Our data show an association of EAO T1D with more AI diseases, higher number of Abs, lower initial insulin reservoir and higher insulin requirements 1 year after diagnosis. In this group, immune imbalance seems more evident and disease progression faster, probably reflecting distinct “immune environment” with different ages at disease onset. Further studies in the field of immunogenetics and immune tolerance are required, to improve patient stratification and find novel targets for therapeutic intervention.

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