Germline-like TCR alpha chains shared between autoreactive T cells in blood and pancreas [dataset1]
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ABSTRACT: How human islet antigen reactive CD4+ memory T cells (IAR T cells) from peripheral blood affect Type 1 Diabetes (T1D) progression in the pancreas is poorly understood. We identified paired alpha/beta (TRA/TRB) T cell receptors (TCRs) in IAR T cells from the blood of healthy, at-risk, new onset, and established T1D donors, and measured sequence overlap with TCRs in pancreata from organ donors. We detected extensive TRA junction sharing between IAR T cells and pancreatic infiltrating T cells (PIT), with perfect or single mismatched TRA junction amino acid sequences comprising ~34% of unique IAR TRA junctions. PIT-matched TRA junctions were largely public, and showed significant nucleotide sequence convergence, increased use of germline-encoded residues in epitope engagement, and a potential for cross-reactivity. The link with T cells in the pancreas implicates autoreactive IAR T cells with shared TRA junctions in the prediabetic and new onset phases of T1D progression.
Project description:How human islet antigen reactive CD4+ memory T cells (IAR T cells) from peripheral blood affect Type 1 Diabetes (T1D) progression in the pancreas is poorly understood. We identified paired alpha/beta (TRA/TRB) T cell receptors (TCRs) in IAR T cells from the blood of healthy, at-risk, new onset, and established T1D donors, and measured sequence overlap with TCRs in pancreata from organ donors. We detected extensive TRA junction sharing between IAR T cells and pancreatic infiltrating T cells (PIT), with perfect or single mismatched TRA junction amino acid sequences comprising ~34% of unique IAR TRA junctions. PIT-matched TRA junctions were largely public, and showed significant nucleotide sequence convergence, increased use of germline-encoded residues in epitope engagement, and a potential for cross-reactivity. The link with T cells in the pancreas implicates autoreactive IAR T cells with shared TRA junctions in the prediabetic and new onset phases of T1D progression.
Project description:Human islet antigen reactive CD4+ memory T cells (IAR T cells) play a key role in the pathogenesis of autoimmune type 1 diabetes (T1D). Using single cell RNA-sequencing (scRNA-seq) to identify T cell receptors (TCRs) in IAR T cells, we have identified a class of TCRs that share TCR alpha chains between individuals (“public”).
Project description:Autoreactive B cells play an important but ill-defined role in autoimmune type 1 diabetes (T1D). To better understand their contribution to disease, we performed single cell gene expression and BCR-seq on pancreatic islet antigen-reactive (IAR) B cells from the peripheral blood of nondiabetic (ND), autoantibody positive prediabetic (AAB), and recent-onset T1D individuals. We found that the frequency of IAR B cells was increased particularly in AAB, but also in T1D compared to ND donors. Additionally, IAR B cells from AAB and T1D donors exhibited differential gene expression in B cell signaling, pro-inflammatory, infection, and antigen processing and presentation pathways compared to ND donors. Strikingly, both AAB and T1D donors demonstrated a significant increase in particular heavy and light chain V gene usages compared to ND, and these B cells were enriched in islet-reactivity. Shared public clones of IAR B cells were found almost entirely among the AAB and T1D donors. IAR B cells were clonally expanded in the autoimmune donors, particularly the AAB group. Notably, a substantial fraction of IAR B cells in AAB and T1D donors appeared to be polyreactive and was confirmed by production of recombinant monoclonal antibodies. Altogether, these results expand our current understanding of B cells during development of T1D, how autoreactive B cells may become activated, and identify unique BCR repertoire differences that may serve as biomarkers for increased disease risk. These findings could be applied to future therapeutic approaches to prevent or treat T1D, as well as assess response to therapy.
Project description:Type 1 diabetes (T1D) is caused by the autoimmune destruction of insulin-producing pancreatic beta cells, leading to life-long dependence on exogenous insulin. Profiling immune cells that infiltrate islets would be invaluable to understanding how beta cell destruction occurs. However, human pancreatic samples demonstrating active infiltration and beta cell destruction are rare. Alternatively, peri-pancreatic lymph nodes (pLNs) or other secondary lymphoid organs may harbor immune cells which participate in memory responses that drive T1D autoimmunity. To study the immune response throughout T1D onset and disease, lymphocytes from pLNs, mesenteric lymph nodes (mesLNs), and the spleen were collected from human T1D, auto-antibody positive (AAb+), and normal donors (NDs) enrolled in the Human Pancreas Analysis Program (HPAP). Tissue immune cell identity, phenotype, and transcriptional status was analyzed using Cellular Indexing of Transcriptomes and Epitopes by Sequencing (CITEseq). Lymphocytes from 17 pLN, 9 mesLN, and 15 spleen samples spanning 7 ND, 5 AAb+, and 7 T1D donors were thawed and processed through the CITEseq pipeline. 5 donors per disease group had a paired pLN and spleen sample, with 3 of the 5 donors having a paired mesLN sample, allowing for cross-tissue immune status comparison spanning multiple stages of disease onset. The dataset provides one of the first and largest CITEseq datasets on human AAb+ and T1D samples publicly available.
Project description:Type 1 Diabetes (T1D) is an autoimmune disease characterized by T cell-mediated destruction of insulin-producing pancreatic β-cells. The pathogenesis of T1D is not fully understood but involves development of autoantibodies (AAbs) followed by a progressive decline in first phase insulin response. Live imaging of T1D pancreatic slices has revealed β cell dysfunction irrespective of the acute presence or absence of CD3+ T cells. However, the mechanisms that drive this dysfunction in the prediabetic period remain unclear. In-situ longitudinal studies of human islet cell biology in the context of T1D are essentially impossible. Hence, we leveraged the availability of pancreas tissues from the Network for Pancreatic Organ donors with Diabetes (nPOD) program to phenotypically and transcriptionally characterize laser capture-microdissected islets across the natural history of T1D.
Project description:Islet-reactive T cells found in peripheral blood of type 1 diabetes (T1D) subjects are thought to be involved in disease pathogenesis, but full understanding of their role is complicated by their presence also in blood of in healthy subjects. To elucidate their role in T1D, we have combined flow cytometry and single cell RNA sequencing (RNA-seq) techniques to link prior antigen exposure, inferred from expanded TCR clonotypes, and functional capacities of islet antigen-reactive CD4+ memory T cells. We find that cells activated by pooled peptides from immunodominant islet antigens showed significantly higher clonotype sharing within recent onset T1D subjects than in healthy individuals, consistent with in vivo T cell expansion during disease progression. There was no clonotype sharing between donors, indicating a predominance of TCRs with distinct or “private” specificities. Expanded clonotypes could be stable, as one was detected at repeat visits by spanning more than a year by one subject. We identified distinct IGRP peptides as the targets of expanded TCR clonotypes from two T1D subjects, thereby implicating this molecule as a trigger for CD4+ T cell expansion during T1D. Transcriptome profiles of cells from T1D and healthy subjects differed, particularly in cells having the most highly expanded TCR clonotypes. As a group, cells with the most highly expanded TCR clonotypes showed Th2-like phenotypes, but at the single cell level there was phenotypic heterogeneity within and between donors. Our findings demonstrate unique specificities and phenotypes of individual islet-reactive CD4+ memory T cells that have expanded during disease progression.
Project description:Islet-reactive T cells found in peripheral blood of type 1 diabetes (T1D) subjects are thought to be involved in disease pathogenesis, but full understanding of their role is complicated by their presence also in blood of in healthy subjects. To elucidate their role in T1D, we have combined flow cytometry and single cell RNA sequencing (RNA-seq) techniques to link prior antigen exposure, inferred from expanded TCR clonotypes, and functional capacities of islet antigen-reactive CD4+ memory T cells. We find that cells activated by pooled peptides from immunodominant islet antigens showed significantly higher clonotype sharing within recent onset T1D subjects than in healthy individuals, consistent with in vivo T cell expansion during disease progression. There was no clonotype sharing between donors, indicating a predominance of TCRs with distinct or “private” specificities. Expanded clonotypes could be stable, as one was detected at repeat visits by spanning more than a year by one subject. We identified distinct IGRP peptides as the targets of expanded TCR clonotypes from two T1D subjects, thereby implicating this molecule as a trigger for CD4+ T cell expansion during T1D. Transcriptome profiles of cells from T1D and healthy subjects differed, particularly in cells having the most highly expanded TCR clonotypes. As a group, cells with the most highly expanded TCR clonotypes showed Th2-like phenotypes, but at the single cell level there was phenotypic heterogeneity within and between donors. Our findings demonstrate unique specificities and phenotypes of individual islet-reactive CD4+ memory T cells that have expanded during disease progression.
Project description:Islet-reactive T cells found in peripheral blood of type 1 diabetes (T1D) subjects are thought to be involved in disease pathogenesis, but full understanding of their role is complicated by their presence also in blood of in healthy subjects. To elucidate their role in T1D, we have combined flow cytometry and single cell RNA sequencing (RNA-seq) techniques to link prior antigen exposure, inferred from expanded TCR clonotypes, and functional capacities of islet antigen-reactive CD4+ memory T cells. We find that cells activated by pooled peptides from immunodominant islet antigens showed significantly higher clonotype sharing within recent onset T1D subjects than in healthy individuals, consistent with in vivo T cell expansion during disease progression. There was no clonotype sharing between donors, indicating a predominance of TCRs with distinct or “private” specificities. Expanded clonotypes could be stable, as one was detected at repeat visits by spanning more than a year by one subject. We identified distinct IGRP peptides as the targets of expanded TCR clonotypes from two T1D subjects, thereby implicating this molecule as a trigger for CD4+ T cell expansion during T1D. Transcriptome profiles of cells from T1D and healthy subjects differed, particularly in cells having the most highly expanded TCR clonotypes. As a group, cells with the most highly expanded TCR clonotypes showed Th2-like phenotypes, but at the single cell level there was phenotypic heterogeneity within and between donors. Our findings demonstrate unique specificities and phenotypes of individual islet-reactive CD4+ memory T cells that have expanded during disease progression.
Project description:Islet-reactive T cells found in peripheral blood of type 1 diabetes (T1D) subjects are thought to be involved in disease pathogenesis, but full understanding of their role is complicated by their presence also in blood of in healthy subjects. To elucidate their role in T1D, we have combined flow cytometry and single cell RNA sequencing (RNA-seq) techniques to link prior antigen exposure, inferred from expanded TCR clonotypes, and functional capacities of islet antigen-reactive CD4+ memory T cells. We find that cells activated by pooled peptides from immunodominant islet antigens showed significantly higher clonotype sharing within recent onset T1D subjects than in healthy individuals, consistent with in vivo T cell expansion during disease progression. There was no clonotype sharing between donors, indicating a predominance of TCRs with distinct or “private” specificities. Expanded clonotypes could be stable, as one was detected at repeat visits by spanning more than a year by one subject. We identified distinct IGRP peptides as the targets of expanded TCR clonotypes from two T1D subjects, thereby implicating this molecule as a trigger for CD4+ T cell expansion during T1D. Transcriptome profiles of cells from T1D and healthy subjects differed, particularly in cells having the most highly expanded TCR clonotypes. As a group, cells with the most highly expanded TCR clonotypes showed Th2-like phenotypes, but at the single cell level there was phenotypic heterogeneity within and between donors. Our findings demonstrate unique specificities and phenotypes of individual islet-reactive CD4+ memory T cells that have expanded during disease progression.
Project description:Type 1 diabetes (T1D) results from autoimmune destruction of β cells in the pancreas. Protein tyrosine phosphatases (PTPs) are candidate genes for T1D and play a key role in autoimmune disease development and β-cell function. Here, we assessed the global protein and individual PTP profile in the pancreas of diabetic NOD mice treated with anti-CD3 mAb and IL-1RA combination therapy. The treatment reversed hyperglycemia compared to the anti-CD3 alone control group. We observed enhanced expression of PTPN2, a T1D candidate gene, and endoplasmic reticulum (ER) chaperones in the islets from cured mice.