Project description:Regulatory T cells (Treg) have been shown to adopt a catabolic metabolic programme with increased capacity for fatty acid oxidation fuelled oxidative phosphorylation (OXPHOS). The role of Foxp3 in this metabolic shift is poorly understood. Here we show that Foxp3 was sufficient to induce a significant increase in the spare respiratory capacity of the cell, the extra OXPHOS capacity available to a cell to meet increased demands on energy in response to work. Foxp3-expressing cells were enhanced in their ability to utilise palmitate for respiration and, in addition, the activity of electron transport complexes I, II and IV were enhanced following Foxp3 expression. Foxp3 also imparts a selective advantage in ATP generation capacity, one that might be exploited as a source of adenosine for functional immunomodulation. In order to explore possible mechanisms for these differences in metabolism we conducted a quantitative proteomics study to compare the contribution of TGFβ and the transcription factor Foxp3 to the Treg proteome. We used quantitative mass spectrometry to examine differences between proteomes of nuclear and cytoplasmic Foxp3-containing CD4+ T cells from various sources with Foxp3- activated CD4 T cells, as well as Treg from human peripheral blood. Gene set enrichment analysis of our proteomic datasets demonstrated that Foxp3 expression is associated with a significant up regulation of several members of the mitochondrial electron transport chain. Not only does Foxp3 influence genes directly concerned with immune function, but also with the energy generating functions of Treg.
Project description:Regulatory T (Treg) cells, whose identity and function are defined by the transcription factor Foxp3, are indispensable for immune homeostasis. It is unclear whether Foxp3 exerts its Treg lineage specification function through active modification of the chromatin landscape and establishment of new enhancers or by exploiting a pre-existing enhancer landscape. Analysis of the chromatin accessibility of Foxp3-bound enhancers in Treg and Foxp3-negative T cells showed that Foxp3 was bound overwhelmingly to pre-accessible enhancers occupied by its cofactors in precursor cells or a structurally related predecessor. Furthermore, the bulk of Foxp3-bound Treg cell enhancers inaccessible in Foxp3- CD4+ cells became accessible upon T cell receptor activation prior to Foxp3 expression with only a small subset associated with several functionally important genes being exclusively Treg cell-specific. Thus, in a late cellular differentiation process Foxp3 defines Treg cell functionality in an “opportunistic” manner by largely exploiting the preformed enhancer network instead of establishing a new enhancer landscape. Array expression. Three cell types with 3-5 replicates each.
Project description:To study the heterogeneity of regulatory T cells (Tregs) in various organs, we performed single-cell RNA sequencing on liver and splenic Treg cells obtained from 12-day and 7-week old mice. Unique Treg subsets in neonatal liver were found and their impact on liver development and maturation was investigated.
Project description:Regulatory T (Treg) cells, whose identity and function are defined by the transcription factor Foxp3, are indispensable for immune homeostasis. It is unclear whether Foxp3 exerts its Treg lineage specification function through active modification of the chromatin landscape and establishment of new enhancers or by exploiting a pre-existing enhancer landscape. Analysis of the chromatin accessibility of Foxp3-bound enhancers in Treg and Foxp3-negative T cells showed that Foxp3 was bound overwhelmingly to pre-accessible enhancers occupied by its cofactors in precursor cells or a structurally related predecessor. Furthermore, the bulk of Foxp3-bound Treg cell enhancers lacking in Foxp3- CD4+ cells became accessible upon T cell receptor activation prior to Foxp3 expression with only a small subset associated with several functionally important genes being exclusively Treg cell-specific. Thus, in a late cellular differentiation process Foxp3 defines Treg cell functionality in an “opportunistic” manner by largely exploiting the preformed enhancer network instead of establishing a new enhancer landscape. Four transcription factors (Foxp3, Ets1, Elf1, and Cbfb) were immunoprecipated while crosslinked to chromatin. These experiments were then combined with DNase-seq data (being uploaded separately as part of ENCODE project) to find that Foxp3 binds exclusively to open chromatin. Data was also leveraged from GSE40657 and GSE33653.
Project description:Regulatory T cells (Treg) contribute to the crucial immunological processes of self-tolerance and immune homeostasis. However, the mechanisms underlying Treg function and cell fate decisions to differentiate between Treg and conventional T cells (Tconv) remain to be fully elucidated, especially at the histone modification level. Covalent modifications of histones establish and maintain chromatin structure, and regulate gene transcription events by facilitating access to cis-elements by trans-acting factors during mammalian development and cellular differentiation. We aimed to investigate the role of the methylation form of histone modification as related to Treg function and phenotype. High-resolution maps of the genome-wide distribution of monomethylated histone H3 lysine 4, H3K4me1, and the trimethylated form H3K4me3 were generated for human activated conventional CD4+CD25+FOXP3- T cells (aTconv) and CD4+CD25+FOXP3+ regulatory T cells (Treg) by sequencing using the Solexa 1G Genetic Analyzer. We found 2115 H3K4me3 regions corresponding to proximal promoter regions; the genes associated with these regions in Treg cells included the crucial transcription factor forkhead box P3 (FOXP3) and the chemokine receptor CCR7. We also identified 41024 Treg cell type-specific H3K4me1 regions. The majority of the H3K4me1 regions differing between the Treg and aTconv cells were located at promoter-distal sites, some of which were selected and consolidated to further examine enhancer activity in in vitro reporter gene assays. The findings from our study provide a comprehensive genome-wide dataset of lineage-specific H3K4me1 and H3K4me3 patterns in Treg and aTconv cells, which may control the differentiation decision, lineage commitment and cell type-specific gene regulation. This basic principle is likely not confined to the two closely-related T cell populations, but may apply generally to somatic cell lineages in adult organisms. Genome-wide distribution of monomethylated histone H3 lysine 4, H3K4me1, and the trimethylated form H3K4me3 in human activated conventional CD4+CD25+FOXP3- T cells (aTconv) and CD4+CD25+FOXP3+ regulatory T cells (Treg) (5 samples in total)
Project description:In this study, we compared the proteomes of mouse CD4+Foxp3+ regulatory T cells (Treg) and CD4+Foxp3- conventional T cells (Tconv) in order to build a data set of proteins differentially regulated in these two cell populations. The data set contains mass spectrometry results from the analysis of 7 biological replicates of Treg/Tconv cell samples purified by flow cytometry, each experiment performed from a pool of 4-5 mice. Global proteomic analysis of each sample was performed by single-run nanoLC-MS/MS, using chromatographic separation of peptides on 50cm C18 reverse-phase columns, with either a 480min gradient on LTQ-Velos orbitrap mass spectrometer (replicates 1 and 2) or a 300min gradient on Q-Exactive orbitrap mass spectrometer (replicates 3-7). Several MS injection replicates were performed for some experiments, leading to 27 raw files composing the data set. The detailed description of each analysis (file name, sample type, biological replicate number, MS technical replicate number, MS instrument used, sample name in MaxQuant ouput) is given in the table “Files list.txt”.
Project description:Natural CD4+FOXP3+ regulatory T (Treg) cells constitute a unique T-cell lineage that plays a pivotal role in maintaining immune homeostasis and immune tolerance. Recent studies provide evidence for the heterogeneity and plasticity of the Treg cell lineage. However, the fate of human Treg cells after loss of FOXP3 expression and the underlying epigenetic mechanisms remain to be fully elucidated. Here, we compared gene expression profiles and histone methylation status on two histone H3 lysine residues (H3K4me3 and H3K27me3) of expanded FOXP3+ and corresponding FOXP3-losing Treg cells. DGE assay showed that human Treg cells down-regulated Treg signature genes, whereas up-regulated a set of Th lineages-associated genes, especially for Th2, such as GATA3, GFI1 and IL13, after in vitro expansion. Furthermore, we found that reprogramming of Treg cells was associated with histone modifications, as shown by decreased abundance of permissive H3K4me3 within down-regulated Treg signature genes, such as FOXP3, CTLA4 and LRRC32 loci, although with no significant changes in H3K27me3 modification. Thus, our results indicate that human Treg cells could convert into a Th-like cells upon in vitro expansion, displaying a gene expression signature dominated by Th2 lineage associated genes, and the histone methylation might contribute to such conversion. mRNA profiles of in-vitro-expanded FOXP3+ Treg and FOXP3-losing Treg cells generated by deep sequencing.
Project description:Regulatory T (Treg) cells, whose identity and function are defined by the transcription factor Foxp3, are indispensable for immune homeostasis. It is unclear whether Foxp3 exerts its Treg lineage specification function through active modification of the chromatin landscape and establishment of new enhancers or by exploiting a pre-existing enhancer landscape. Analysis of the chromatin accessibility of Foxp3-bound enhancers in Treg and Foxp3-negative T cells showed that Foxp3 was bound overwhelmingly to pre-accessible enhancers occupied by its cofactors in precursor cells or a structurally related predecessor. Furthermore, the bulk of Foxp3-bound Treg cell enhancers inaccessible in Foxp3- CD4+ cells became accessible upon T cell receptor activation prior to Foxp3 expression with only a small subset associated with several functionally important genes being exclusively Treg cell-specific. Thus, in a late cellular differentiation process Foxp3 defines Treg cell functionality in an “opportunistic” manner by largely exploiting the preformed enhancer network instead of establishing a new enhancer landscape.
Project description:Regulatory T (Treg) cells, whose identity and function are defined by the transcription factor Foxp3, are indispensable for immune homeostasis. It is unclear whether Foxp3 exerts its Treg lineage specification function through active modification of the chromatin landscape and establishment of new enhancers or by exploiting a pre-existing enhancer landscape. Analysis of the chromatin accessibility of Foxp3-bound enhancers in Treg and Foxp3-negative T cells showed that Foxp3 was bound overwhelmingly to pre-accessible enhancers occupied by its cofactors in precursor cells or a structurally related predecessor. Furthermore, the bulk of Foxp3-bound Treg cell enhancers lacking in Foxp3- CD4+ cells became accessible upon T cell receptor activation prior to Foxp3 expression with only a small subset associated with several functionally important genes being exclusively Treg cell-specific. Thus, in a late cellular differentiation process Foxp3 defines Treg cell functionality in an “opportunistic” manner by largely exploiting the preformed enhancer network instead of establishing a new enhancer landscape.
Project description:The aim of this study was to quantify the impact of chimeric Foxp3-GFP protein on the Treg cell transcriptional program. Duplicate samples of Tconv (CD3+CD4+GFP-) and Treg (CD3+CD4+GFP+) splenocytes were double-sorted to achieve > 99.0% purity, from 6 weeks old male Foxp3-Fusion-GFP and Foxp3-ires-GFP mice of both B6 and NOD backgrounds. Following cell sorting into Trizol, RNA was purified, labeled and hybridized to Affymetrix arrays.