Project description:In an accompanying paper we found specific localization of diabetogenic T cells only to islets of Langerhans bearing the specific antigen. Instrumental in the specific localization was the presence of intra-islet dendritic cells bearing the β-cell-peptide-MHC complex. Here we report that the entry of diabetogenic CD4 T cells very rapidly triggered inflammatory gene expression changes in islets and vessels by up-regulating chemokines and adhesion molecules. VCAM-1 expression was notable in blood vessels and so was ICAM-1. ICAM-1 was also found on β-cells. These expression changes induced the entry of non-specific T cells that otherwise did not localize to the islets. In contrast to the entry of diabetogenic CD4 T cells, the entrance of non-specific T cells required a chemokine response and VCAM-1 expression by the islets. Interferon-gamma was important for the early gene expression changes in the islets. By microarray analysis we detected up-regulation of a group of interferon-inducible genes as early as 8 hours post T cell transfer. These studies provide a baseline to examine the development of therapeutics that can modulate islet localization of diabetogenic T cells to control this autoimmune disease. 20 total samples
Project description:In an accompanying paper we found specific localization of diabetogenic T cells only to islets of Langerhans bearing the specific antigen. Instrumental in the specific localization was the presence of intra-islet dendritic cells bearing the β-cell-peptide-MHC complex. Here we report that the entry of diabetogenic CD4 T cells very rapidly triggered inflammatory gene expression changes in islets and vessels by up-regulating chemokines and adhesion molecules. VCAM-1 expression was notable in blood vessels and so was ICAM-1. ICAM-1 was also found on β-cells. These expression changes induced the entry of non-specific T cells that otherwise did not localize to the islets. In contrast to the entry of diabetogenic CD4 T cells, the entrance of non-specific T cells required a chemokine response and VCAM-1 expression by the islets. Interferon-gamma was important for the early gene expression changes in the islets. By microarray analysis we detected up-regulation of a group of interferon-inducible genes as early as 8 hours post T cell transfer. These studies provide a baseline to examine the development of therapeutics that can modulate islet localization of diabetogenic T cells to control this autoimmune disease.
Project description:In the NOD mouse model of autoimmune diabetes, IL-27 stimulates CD4 and CD8 T cells to enhance their IFNγ production and diabetogenic capacity. Here, single-cell RNA sequencing and T cell adoptive transfer showed that IL-27 intrinsically controlled the differentiation of islet-infiltrating CD4 T cells by driving them toward an IL-21+ Th1 phenotype. Consequently, IL-27 signaling in CD4 T cells was important for BATF and granzyme B expression in islet CD8 T effectors. Complete absence of IL-21 signaling in CD8 T cells additionally impaired their cytokine production. BATF overexpression increased the diabetogenic potential of β-cell autoreactive CD8 T cells lacking help from CD4 T cell-derived IL-21. Macrophages were the main source of IL-27 in islets, whose expression correlated with T cell infiltration. IFNγ and CD40 signaling conferred by activated T cells induced macrophage IL-27 production. Collectively, our findings reveal a role of IL-27 in orchestrating interconnected positive feedback loops involving CD4 T cells, CD8 T cells, and macrophages in autoimmune diabetes.
Project description:Interleukin (IL)-21 is essential for type 1 diabetes (T1D) development in the NOD mouse model. IL-21-expressing CD4 T cells are present in pancreatic islets where they contribute to disease progression. However, little is known about their phenotype and differentiation states. To fill this gap, we generated a novel IL-21 reporter NOD strain to further characterize IL-21+ CD4 T cells in T1D. IL-21+ CD4 T cells accumulate in pancreatic islets and recognize β-cell antigens. Single-cell RNA sequencing revealed that most CD4 T effector cells in islets actively express IL-21 and they are highly diabetogenic despite expressing multiple inhibitory molecules, including PD-1 and LAG3. Islet IL-21+ CD4 T cells segregate into four phenotypically and transcriptionally distinct differentiation states, less differentiated early effectors, Tfh-like cells, and two Th1 subsets. Trajectory analysis predicts that early effectors differentiate into both Tfh-like and terminal Th1 cells. We further demonstrated that intrinsic IL-27 signaling controls the differentiation of islet IL-21+ CD4 T cells, contributing to their helper function. Collectively, our study reveals the heterogeneity of islet-infiltrating IL-21+ CD4 T cells and indicates that both Tfh-like and Th1 subsets continuously produce IL-21 throughout their differentiation process, highlighting the important sources of IL-21 in T1D pathogenesis.
Project description:T cells infiltrate pancreatic islets during the progression of type 1 diabetes (T1D) but their differentiation states have not been completely defined. We used unbiased single-cell RNA sequencing analyses to gain further insight into the phenotypic complexity of islet-infiltrating T cells in non-obese diabetic (NOD) mice. In the CD4 T cell compartment, we identified naïve, memory, and regulatory T cells, as well as multiple Il21 expressing effector subsets positive for markers indicative of Th1 and Tfh cells. In CD8 T cells, we identified two activated subsets in addition to naïve cells. The two activated islet CD8 T cell subsets respectively resemble the self-renewing progenitor cells and the terminally differentiated/exhausted effectors during chronic lymphocytic choriomeningitis virus infection. We also identified a BATF-driven transcriptional signature promoting the diabetogenic activity of islet-infiltrating β cell autoreactive CD8 T effectors. Our results provide a useful resource for understanding T cell differentiation programs in T1D.
Project description:T cells infiltrate pancreatic islets during the progression of type 1 diabetes (T1D) but their differentiation states have not been completely defined. We used unbiased single-cell RNA sequencing analyses to gain further insight into the phenotypic complexity of islet-infiltrating T cells in non-obese diabetic (NOD) mice. In the CD4 T cell compartment, we identified naïve, memory, and regulatory T cells, as well as multiple Il21 expressing effector subsets positive for markers indicative of Th1 and Tfh cells. In CD8 T cells, we identified two activated subsets in addition to naïve cells. The two activated islet CD8 T cell subsets respectively resemble the self-renewing progenitor cells and the terminally differentiated/exhausted effectors during chronic lymphocytic choriomeningitis virus infection. We also identified a BATF-driven transcriptional signature promoting the diabetogenic activity of islet-infiltrating β cell autoreactive CD8 T effectors. Our results provide a useful resource for understanding T cell differentiation programs in T1D.
2024-01-22 | GSE125452 | GEO
Project description:Genome-wide association, RNA-seq and iTRAQ analyses identify candidate genes controlling radicle length of wheat
Project description:Autoreactive CD8+ T-cells recognizing autoantigens expressed by pancreatic islets lead to the destruction of insulin-producing β-cells in type 1 diabetes, but these T-cell also occur in healthy subjects. We tested the hypothesis that uncontrolled expansion of diabetogenic T-cells in patients occurs, resulting from failure to activate apoptosis. We compared function, transcriptome and epigenetic regulation thereof in relation with fate upon repeated exposure to islet-autoantigen of islet autoreactive T-cells from healthy and type 1 diabetic donors with identical islet epitope specificity and HLA-A2 restriction. Patient's T-cells proliferated exponentially, whereas those of non-diabetic origin succumbed to cell death. Transcriptome analysis revealed reduced expression of TRAIL, TRAIL-R2, FAS and FASLG (members of the extrinsic apoptosis pathway) in patient-derived compared to healthy-donor-derived T cells. This was mirrored by increased expression of microRNAs predicted to regulate these particular genes, namely miR-98, miR-23b and miR-590-5p. Gene specific targeting by these microRNAs was confirmed using dual-luciferase reporter assays. Finally, transfection of these microRNAs into primary T-cells reduced FAS and TRAIL mRNA underscoring their functional relevance. We propose that repression of pro-apoptotic pathways by microRNAs contributes to unrestricted expansion of diabetogenic cytotoxic T-cells, implicating microRNA-mediated gene silencing in islet autoimmunity in T1D.
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.
Project description:We demonstrate diverse roles of interferonâgamma (IFN-γ) in the induction and regulation of immune-mediated inflammation using a transfer model of autoimmune diabetes. The diabetogenic CD4+BDC2.5 (BDC) T cell clone upon transfer into NOD.scid mice induced destruction of islets of Langerhans leading to diabetes. Administration of a neutralizing antibody to IFN-γ (H22) resulted in long term protection (LTP) from diabetes, with inflammation but persistence of a significant, albeit decreased numbers of β-cells. BDC T cells were a mixture of cells expressing high, intermediate and low levels of the T cell receptor. Clonotype-low BDC T cells were required for LTP. Furthermore, islet infiltrating leukocytes in the LTP mice contained Foxp3+CD4 T cells. Islet inflammation in both diabetic and LTP mice was characterized by heavy infiltration of macrophages. Gene expression profiles indicated that macrophages in diabetic mice were M1-type, while LTP mice contained M2-differentiated. The LTP was abolished if mice were treated with either an antibody depleting CD4 T cells, or a neutralizing antibody to CTLA-4, in this case, only at a late stage. Neutralization of IL-10, TGF-β, GITR or CD25 had no effect. Transfer of only clonotype-high expressing BDC T cells induced diabetes but in contrast, H22 antibodies did not inhibit diabetes. While clonotype high T cells induced diabetes even when IFN-γ was neutralized, paradoxically, there was reduced inflammation and no diabetes if host myeloid cells lacked IFN-γ receptor. Hence, using monoclonal CD4 T cells, IFN-γ can have a wide diversity of roles, depending on the setting of the immune process. Experiment Overall Design: Pancreatic islets were laser-capture microdissected from mice injected with diabetogenic T cells. One cohort of mice also received injections with anti-interfereon gamma monoclonal antibody, which protected those mice from developing diabetes. RNA prepared from islets was amplified and analyzed by Affymetrix GeneChips. Each GeneChip was prepared from RNA pooled from 5 mice at each timepoint. GeneChips were prepared from RNA extracted at different days following injection of T cells. The following days were assayed day 0 (i.e., untreated), day 3 (for diabetic and protected islets), day 4 (diabetic and protected), day 5 (only for protected, as diabetic islets were too edematous to dissect), day 8 (diabetic and protected).