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Comparsion of IGRP reactive CD8 T cell clones

ABSTRACT: 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.

ORGANISM(S): Homo sapiens

PROVIDER: GSE80569 | GEO | 2016/05/21

SECONDARY ACCESSION(S): PRJNA319327

REPOSITORIES: GEO

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Project description:We demonstrate diverse roles of interferonâgamma (IFN-Î³) 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-Î³ (H22) resulted in long term protection (LTP) from diabetes, with inflammation but persistence of a significant, albeit decreased numbers of Î²-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-Î², 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-Î³ was neutralized, paradoxically, there was reduced inflammation and no diabetes if host myeloid cells lacked IFN-Î³ receptor. Hence, using monoclonal CD4 T cells, IFN-Î³ 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).

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Comparsion of IGRP reactive CD8 T cell clones

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