EOMES-expressing CD4+ T cells are increased in PTPN22 (1858T) risk allele carriers
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ABSTRACT: The presence of the PTPN22 risk variant (1858T) is associated to several autoimmune diseases including rheumatoid arthritis (RA). Despite a number of studies exploring the function of PTPN22 in T cells, the exact impact of the PTPN22 risk variant on T cell function in humans is still unclear. In this study, using RNA sequencing, we show that, upon TCR-activation, naïve CD4+ T cells carrying two PTPN22 risk alleles overexpress a limited number of genes including CFLAR and 4-1BB important for cytotoxic T cell differentiation. Moreover, an increased number of cytotoxic EOMES+ CD4+ T cells were observed in PTPN22 risk allele carriers, which negatively correlated with a decreased number of naïve T cells in older individuals. No difference in the frequency of other CD4+ T cell subsets (Th1, Th17, Tfh, Treg) was observed in PTPN22 risk allele carriers and Treg suppressive capacity was not altered. Finally, in synovial fluids of RA patients, an accumulation of EOMES+ CD4+ T cells was observed with a more pronounced production of Perforin-1 in PTPN22 risk allele carriers. Altogether, our data provide a novel mechanism of action of PTPN22 risk variant on CD4+ T-cell differentiation and identify EOMES+ CD4+ T cell as a relevant T cell subset in RA.
Project description:Protein tyrosine phosphatase nonreceptor type 22 (PTPN22) gene segregates with most autoimmune diseases; its risk allele encodes overactive PTPN22 phosphatases that alter B cell receptor (BCR) signaling potentially involved in the regulation of central B cell tolerance. To assess whether PTPN22 risk allele affects the removal of developing autoreactive B cells, we tested by ELISA the reactivity of recombinant antibodies isolated from single B cells from asymptomatic healthy individuals carrying one or two PTPN22 risk allele(s). We found that new emigrant/transitional and mature naive B cells from PTPN22 risk allele carriers contained high frequencies of autoreactive clones compared to non-carrier control donors. Hence, a single PTPN22 risk allele has a dominant effect on altering autoreactive B cell counterselection, suggesting that early B cell tolerance checkpoint defects precede the onset of autoimmunity. In addition, gene array experiments comparing mature naïve B cells from healthy individuals carrying or not PTPN22 risk allele(s) revealed that the strength of association of PTPN22 for autoimmunity, second in importance only to the MHC, may not only be due to BCR signaling alteration but also to the regulation of other genes, which themselves have also been identified as involved in the development of autoimmune diseases. The PTPN22 risk allele is a single nucleotide change (cytidine to thymidine) at residue 1858, which results in a single amino acid substitution from arginine to tryptophan at position 620 of the PTPN22/Lyp protein. Data from mature naïve B cell populations from patients carrying 1 or 2 PTPN22 T alleles and non-carrier patients were compared in order to characterize the impact of PTPN22 polymorphism on B cell physiology. RNA was extracted from batch-sorted CD19+CD10-CD21+CD27- conventional mature naive B cells using the Absolutely RNA microprep kit (Stratagene). 100-200 ng of RNA was obtained per sample, and the quality of the purified RNA was assessed by the Bioanalyzer from Agilent. Using the Ovation biotin system kit from Nugen, 30-50ng of RNA was amplified and labeled to produce cDNA. Labeled cDNA was hybridized on chips containing the whole human genome (Human Genome U133 Plus 2.0 from Affymetrix).
Project description:Protein tyrosine phosphatase nonreceptor type 22 (PTPN22) gene segregates with most autoimmune diseases; its risk allele encodes overactive PTPN22 phosphatases that alter B cell receptor (BCR) signaling potentially involved in the regulation of central B cell tolerance. To assess whether PTPN22 risk allele affects the removal of developing autoreactive B cells, we tested by ELISA the reactivity of recombinant antibodies isolated from single B cells from asymptomatic healthy individuals carrying one or two PTPN22 risk allele(s). We found that new emigrant/transitional and mature naive B cells from PTPN22 risk allele carriers contained high frequencies of autoreactive clones compared to non-carrier control donors. Hence, a single PTPN22 risk allele has a dominant effect on altering autoreactive B cell counterselection, suggesting that early B cell tolerance checkpoint defects precede the onset of autoimmunity. In addition, gene array experiments comparing mature naïve B cells from healthy individuals carrying or not PTPN22 risk allele(s) revealed that the strength of association of PTPN22 for autoimmunity, second in importance only to the MHC, may not only be due to BCR signaling alteration but also to the regulation of other genes, which themselves have also been identified as involved in the development of autoimmune diseases. The PTPN22 risk allele is a single nucleotide change (cytidine to thymidine) at residue 1858, which results in a single amino acid substitution from arginine to tryptophan at position 620 of the PTPN22/Lyp protein.
Project description:Our fine-mapping of 76 non-MHC loci associated with risk for rheumatoid arthritis (RA, 11,475 cases, 15,870 controls) has recently identified rs117701653, a non-coding single nucleotide polymorphism (SNP) in the CTLA4/CD28/ICOS locus, as the variant most likely to modulate RA risk within this region, with the minor allele (C) showing disease protection compared to the major allele (A). Notably, this SNP exhibits allele-specific protein binding, further supporting its regulatory nature, including greater binding of proteins from Jurkat T cell nuclear extract to the protective allele (C) than to the risk allele (A) by electrophoretic mobility shift assay (EMSA). To identify this protein or protein complex, we applied an efficient DNA pulldown technique, flanking restriction enhanced pulldown (FREP), using nuclear extract from Jurkat T cells, bait DNA corresponding to the (C) allele of rs117701653, competitor DNA fragment, and irrelevant DNA sequence as a negative control. Mass spectrometry analysis of peptides released from FREP identified 43 proteins. Our strongest candidate was structural maintenance of chromosomes flexible hinge domain-containing protein 1 (SMCHD1), which exhibited specific binding to the (C) allele of rs117701653. We confirmed the allelic affinity of SMCHD1 using multiple orthogonal approaches, including FREP and western blotting, EMSA with anti-SMCHD1 antibodies, and CHIP-qPCR with CRISPR-modified Jurkat clones bearing different genotype at rs117701653. In this study, we identified SMCHD1, a chromatin regulator that binds allelically to the rs117701653 allele (C) associated with protection against RA risk.
Project description:To gain mechanistic insights into how EOMES regulates CD4+ T-cell differentiation and function, we performed an RNA-seq analysis using Eomes-GFP reporter mice (Eomes+/GFP) to isolate GFP+ (EOMES+) and GFP- (EOMES-) CD4+ T-cells by FACS sorting. We also sequenced RNA from Eomes-deficient GFP+ and GFP- CD4+ T-cells isolated from EomesΔT/GFP knock-out mice, in which one Eomes allele is disrupted by GFP insertion and the DNA-binding domain of the other allele is deleted in T cells by Lck-driven Cre recombinase. Hence, we had two populations of GFP+ cells where the EOMES locus was transcribed, one with a transcriptionally active EOMES protein (Eomes+/GFP) and another one with no transcriptionally active EOMES (EomesΔT/GFP), plus the respective GFP-negative controls isolated from the same mice. A homogeneous population of EOMES-expressing CD4+ T cells were obtained by transferring naïve sorted CD25- CD45RBhigh CD4+ T-cells isolated from Eomes+/GFP reporter or EomesΔT/GFP knock-out donor animals into Rag2-/- mice. After three weeks of adoptive transfer GFP+ and GFP- CD4+ T-cell populations from these mice were FACS-sorted for transcriptome analysis by RNA sequencing.
Project description:In this study, we examine gene expression and function of immune cell subsets to demonstrate how a common allelic variant of PTPN22, which strongly increases the risk of autoimmune disease, promotes successful clearance of an otherwise chronic viral infection.
Project description:Fine-mapping and functional studies implicate rs117701653, a common non-coding variant in the CD28/CTLA4/ICOS locus, as a contributor to risk for rheumatoid arthritis and type 1 diabetes. Using DNA pulldown, mass spectrometry, genome editing and eQTL analysis, we establish that the disease-associated allele reduces affinity for the inhibitory chromosomal regulator SMCHD1 to drive expression of inducible T-cell costimulator (ICOS), enhancing memory CD4+ T cell ICOS expression in individuals bearing the risk allele. Higher ICOS expression is paralleled by an increase in circulating T peripheral helper (Tph) cells, and in rheumatoid arthritis patients, of blood and joint fluid Tph cells and circulating plasmablasts, suggesting a causal link. Indeed, ICOS ligation accelerates T cell differentiation into CXCR5-PD-1high Tph cells producing IL-21 and CXCL13, as does carriage of the rs117701653 risk allele. Thus, mechanistic dissection of a causal non-coding variant in human autoimmunity discloses a new pathway through which ICOS regulates Tph abundance.
Project description:Background and Objectives: The rs763361 non-synonymous (Gly307Ser) variant in the CD226 gene has been identified as a risk factor for several immune-mediated diseases, including multiple sclerosis (MS). Compelling evidence suggests that this allele may be one of the genetic driving forces contributing to suceptibility to MS by decreasing the immune-regulatory capacity of Treg cells and increasing the pro-inflammatory potential of CD4 T cells. However, the impact of this CD gene variant on CD8 T cell functions, a population that also plays a key role in MS, remain T to be determined. Methods: In order to study whether the CD226 risk variant affects human CD8 T cells functions, we used CD8 T cells isolated from PBMC of 16-age matched healthy donors homozygous for either the protective or risk allele of CD226. We characterized these CD8 T cells upon TCR stimulation using high-parametric flow cytometry, bulk RNAseq, and through characterization of canonical signaling pathways and cytokine production. Results: Upon TCR engagment, the phenotype of ex vivo CD8 T cells bearing the protective (CD226-307Gly) or the risk (CD226-307Ser) allele of CD226 was largely overlapping. However, transcriptomic signature of CD8 T cells from the donor carrying the risk allele presented an enrichment in TCR, JAK/STAT and INFg signaling.
Project description:Differences in DNA methylation have been reported in B and T lymphocyte populations, including CD4+ T cells, isolated from rheumatoid arthritis (RA) patients when compared to healthy controls. CD4+ T cells are a heterogeneous cell type with subpopulations displaying distinct DNA methylation patterns. In this study, we investigated DNA methylation using reduced representation bisulfite sequencing in two CD4+ T cell populations (CD4+ memory and naïve cells) in three groups: newly diagnosed, disease modifying antirheumatic drugs (DMARD) naïve RA patients (N=11), methotrexate (MTX) treated RA patients (N=18), and healthy controls (N=9) matched for age, gender and smoking status. Analyses of these data revealed significantly more differentially methylated positions (DMPs) in CD4+ memory than in CD4+ naïve T cells (904 vs 19 DMPs) in RA patients compared to controls. The majority of DMPs (72%) identified in newly diagnosed and DMARD naïve RA patients with active disease showed increased DNA methylation (39 DMPs), whereas most DMPs (80%) identified in the MTX treated RA patients in remission displayed decreased DNA methylation (694 DMPs). Interestingly, we also found that about one third of the 101 known RA risk loci overlapped (+/- 500 kb) with the DMPs. Notably, introns of the UBASH3A gene harbour both the lead RA risk SNP and two DMPs in CD4+ memory T cells. Our results suggest that RA associated DNA methylation differences vary between the two T cell subsets, but are also influenced by RA characteristics such as disease activity, disease duration and/or MTX treatment.
Project description:In the Greenlandic Inuit population, 17% are carriers of a nonsense TBC1D4 p.Arg684Ter variant. Homozygous variant carriers have impaired glucose tolerance and a 10-fold increased risk of type 2 diabetes. Here, we illuminate the consequences of lacking this muscle-specific long isoform of TBC1D4 during metabolic challenges in humans.