FOXP3+ regulatory T cell development and function require histone/protein deacetylase 3
ABSTRACT: Treg dysfunction is associated with a variety of inflammatory diseases. Treg populations are defined by expression of the oligomeric transcription factor FOXP3 and inability to produce IL-2, a cytokine required for T cell maintenance and survival. FOXP3 activity is regulated post-translationally by histone/protein acetyltransferases and histone/protein deacetylases (HDACs). Here, we determined that HDAC3 mediates both the development and function of the two main Treg subsets, thymus-derived Tregs and induced Tregs (iTregs). We determined that HDAC3 and FOXP3 physically interact and that HDAC3 expression markedly reduces Il2 promoter activity. In murine models, conditional deletion of Hdac3 during thymic Treg development restored Treg production of IL-2 and blocked the suppressive function of Tregs. HDAC3-deficient mice died from autoimmunity by 4-6 weeks of age; however, injection of WT FOXP3+ Tregs prolonged survival. Adoptive transfer of Hdac3-deficient Tregs, unlike WT Tregs, did not control T cell proliferation in naive mice and did not prevent allograft rejection or colitis. HDAC3 also regulated the development of iTregs, as HDAC3-deficient conventional T cells were not converted into iTregs under polarizing conditions and produced large amounts of IL-2, IL-6, and IL-17. We conclude that HDAC3 is essential for the normal development and suppressive functions of thymic and peripheral FOXP3+ Tregs. RNA was isolated using RNeasy kits (QIAGEN), and RNA integrity and quantity were analyzed by NanoDrop ND-1000 and Nanochip 2100 Bioanalyzer (Agilent Technologies). Microarray experiments were performed using whole mouse genome oligoarrays (Mouse430a, Affymetrix) and array data analyzed using MAYDAY 2.12 software. Array data were subjected to robust multiarray average (RMA) normalization and analyzed using Student’s t test. Only data with a false discovery rate-adjusted P value of less than 0.05 and at least 2× differential expression were included in the analysis. Data underwent z-score transformation for display.
Project description:The proposed use of Foxp3+ T-regulatory (Treg) cells as potential cellular therapy in patients with autoimmune diseases, or post-hemopoietic stem cell or organ transplantation, requires a sound understanding of the transcriptional regulation of Foxp3 expression. Conserved CpG dinucleotides in the Treg-specific demethylated region (TSDR) upstream of Foxp3 are demethylated only in stable, thymic-derived Foxp3+ Tregs. Since methyl-binding domain (Mbd) proteins recruit histone-modifying and chromatin-remodeling complexes to methylated sites, we tested whether targeting of Mbd2 might promote demethylation of Foxp3 and thereby promote Treg numbers or function. Surprisingly, while ChIP analysis showed Mbd2 binding to the Foxp3-associated TSDR site in Tregs, Mbd2 targeting by homologous recombination or siRNA decreased Treg numbers and impaired Treg suppressive function in vitro and in vivo. Moreover, we found complete TSDR demethylation in WT Tregs but >75% methylation in Mbd2-/- Tregs, whereas re-introduction of Mbd2 into Mbd2-null Tregs restored TSDR demethylation, Foxp3 gene expression and Treg suppressive function. Lastly, Mbd2-/- Tregs had markedly binding of the DNA demethylase enzyme, Tet2, in the TSDR region. These data show that Mbd2 has a key role in promoting TSDR demethylation, Foxp3 expression and Treg suppressive function. RNA from three independent samples from magnetically separated CD4+CD25+ Treg of MBD2–/– mice, compared to wild type control (all Balb/c background).
Project description:Foxp3 expressing regulatory T cells (Tregs) are the central regulator of immune homeostasis and tolerance. As it is believed that proper Treg function is compromised under inflammatory conditions, exploring a pathway that enhances Treg function is of great importance. In this study, we report that IL-27, an IL-12 family cytokine known to play both pro- and anti-inflammatory role in T cells, plays a pivotal role in Treg function to control T cell-induced colitis. Unlike WT Tregs capable of inhibiting colitogenic T cell expansion and inflammatory cytokine expression, IL-27R-deficient Tregs were unable to downregulate inflammatory T cell responses. Tregs stimulated with IL-27 expressed substantially enhanced suppressive function both in vitro and in vivo. IL-27 stimulation of Tregs induced expression of LAG3, a surface molecule implicated in negatively regulating immune responses. LAG3 expression in IL-27-stimulated Tregs was critical to mediate suppressive Treg function. Finally, human Tregs also displayed enhanced suppressive function and LAG3 expression in response to IL-27 stimulation. Taken together, our results highlight a novel function of the IL-27/LAG3 axis in Treg regulation of inflammatory responses in the intestine. FACS purified Foxp3+ Tregs were stimulated in the presence of media or IL-27 to compare IL-27 induced gene profiles. Four samples (media stimulated or IL-27-stimulated) were collected from four independent experiments. Genes altered by IL-27 treatment were compared to those of media stimulated Tregs.
Project description:We investigated the role of DNMT1 in immune homeostasis by generating mice lacking DNMT1 in Foxp3+ T-regulatory (Treg) cells. These mice showed decreased peripheral Foxp3+ Tregs, complete loss of Foxp3+ Treg suppressive functions in vitro and in vivo, and died from autoimmunity by 3-4 weeks unless they received perinatal transfer of wild-type Tregs that prolonged their survival. Methylation of CpG-sites in the TSDR region of Foxp3 was unaffected by DNMT1 deletion, but microarray revealed more >500 proinflammatory and other genes were upregulated in DNMT1-/- Tregs. CD4-Cre-mediated DNMT1 deletion showed inability of conventional T cells to convert to Foxp3+ Treg under appropriate polarizing conditions. Hence, DNMT1 is absolutely necessary for maintenance of the gene program required for normal Treg development and function. RNA from three independent samples of magnetically separated CD4+CD25+ Treg of fl-DNMT1/Foxp3cre mice, compared to wild type (C57BL6) control
Project description:A new Treg-specific, FoxP3-GFP-hCre BAC transgenic was crossed to a conditional Dicer knock-out mouse strain to analyze the role of microRNAs (miRNA) in the development and function of regulatory T cells (Tregs). Although thymic Tregs developed normally in this setting, the cells showed evidence of altered differentiation and dysfunction in the periphery. Dicer-deficient Treg lineage cells failed to remain stable as a subset of cells down-regulated the Treg-specific transcription factor, FoxP3, while the majority expressed altered levels of multiple genes and proteins (including Neuropilin 1, GITR and CTLA-4) associated with the Treg fingerprint. In fact, a significant percentage of the Treg lineage cells took on a Th memory phenotype including increased levels of CD127, IL-4, and interferon-g. Importantly, Dicer-deficient Tregs lost suppression activity in vivo; the mice rapidly developed fatal systemic autoimmune disease resembling the FoxP3 knockout phenotype. These results support a central role for miRNAs in maintaining the stability of differentiated Treg function in vivo and homeostasis of the adaptive immune system. Overall design: Lymph node CD4+YFP+ T cells from FoxP3-GFP-hCre x ROSA26R-YFP Dicerwt/lox (Het) and FoxP3-GFP-hCre x ROSA26R-YFP Dicerlox/lox (KO) mice were isolated by flow cytometry. Triplicate GeneChips were used for each T cell population.
Project description:A new Treg-specific, FoxP3-GFP-hCre BAC transgenic was crossed to a conditional Dicer knock-out mouse strain to analyze the role of microRNAs (miRNA) in the development and function of regulatory T cells (Tregs). Although thymic Tregs developed normally in this setting, the cells showed evidence of altered differentiation and dysfunction in the periphery. Dicer-deficient Treg lineage cells failed to remain stable as a subset of cells down-regulated the Treg-specific transcription factor, FoxP3, while the majority expressed altered levels of multiple genes and proteins (including Neuropilin 1, GITR and CTLA-4) associated with the Treg fingerprint. In fact, a significant percentage of the Treg lineage cells took on a Th memory phenotype including increased levels of CD127, IL-4, and interferon-g. Importantly, Dicer-deficient Tregs lost suppression activity in vivo; the mice rapidly developed fatal systemic autoimmune disease resembling the FoxP3 knockout phenotype. These results support a central role for miRNAs in maintaining the stability of differentiated Treg function in vivo and homeostasis of the adaptive immune system. Experiment Overall Design: Lymph node CD4+YFP+ T cells from FoxP3-GFP-hCre x ROSA26R-YFP Dicerwt/lox (Het) and FoxP3-GFP-hCre x ROSA26R-YFP Dicerlox/lox (KO) mice were isolated by flow cytometry. Triplicate GeneChips were used for each T cell population.
Project description:Foxp3+ T-regulatory cells (Tregs) are key to immune homeostasis such that their diminished numbers or function can cause autoimmunity and allograft rejection. Foxp3+ Tregs express histone/protein deacetylases (HDACs) that regulate chromatin remodeling, gene expression and protein function. Pan-HDAC inhibitors developed for oncology enhance Treg production and suppression but have limited non-oncologic applications given their broad effects. We show, using HDAC6-deficient mice and WT mice treated with HDAC6-specific inhibitors, that HDAC6 inhibition promotes Treg suppressive activity in models of inflammation and autoimmunity, including multiple forms of experimental colitis and fully MHC-incompatible cardiac allograft rejection. Many of the beneficial effects of HDAC6 targeting are also achieved by inhibition of the HDAC6-regulated protein, HSP90. Hence, selective targeting of a single HDAC isoform, HDAC6, or its downstream target, HSP90, can promote Treg-dependent suppression of autoimmunity and transplant rejection. RNA from three independent samples from magnetically separated CD4+CD25+ Treg of HDAC6 knock out, compared to wild type (C57BL6) control
Project description:Foxp3+ T-regulatory (Treg) cells maintain immune homeostasis and limit autoimmunity, but can also curtail host responses to cancers. Tregs are therefore promising targets to enhance anti-tumor immunity. Histone/protein acetyltransferases (HATs) promote chromatin accessibility, gene transcription and the function of multiple transcription factors and non-histone proteins. We found that conditional deletion or pharmacologic inhibition of one specific HAT, p300, in Foxp3+ Tregs, increased TCR-induced apoptosis in Tregs, impaired Treg suppressive function and iTreg peripheral conversion, and limited tumor growth in immunocompetent, but not in immunodeficient, hosts. Our data demonstrate that p300 is important for Foxp3+ Treg function and homeostasis in vivo and in vitro, and identify a novel mechanism to diminish Treg function without overtly impairing effector Tcell responses or inducing autoimmunity. Collectively, these data suggest a new approach for cancer immunotherapy. RNA from three independent samples from magnetically separated CD4+CD25+ Treg of fl-p300/Foxp3cre mice, compared to wild type (Foxp3cre) control (all C57Bl/6 background).
Project description:Regulatory T cells (Tregs) are responsible for limiting autoimmunity and chronic inflammation. Foxp3 is a transcription factor that acts as a master regulator of Treg development and function. A serendipitous observation led to the realization that a well-characterized Foxp3gfp reporter mouse, which expresses an N-terminal GFP-Foxp3 fusion protein, is a hypomorph that causes profoundly accelerated autoimmune diabetes on a NOD background. Although natural Treg development and in vitro function is not significantly altered in Foxp3gfp NOD and C57BL/6 mice, Treg fitness function in inflammatory environments is perturbed and TGFβ-induced Treg development reduced. Foxp3gfpis unable to interact with the histone acetyltransferase Tip60, the histone deacetylase HDAC7, and the Ikaros family zinc finger 4, Eos, which leads to reduced Foxp3 acetylation and enhanced K48-linked polyubiquitylation. Collectively this leads to an altered transcriptional landscape and reduced Foxp3-mediated gene repression, notably at the hallmark IL-2 promoter. Loss of controlled Foxp3-driven epigenetic modification leads to Treg insufficiency that causes autoimmunity in prone environments. 16 samples overall split between 2 genotypes (wild type and Foxp3 knock in) and two cell types (Tregs and Tconv)
Project description:LKB1 deficiency in Treg cells impairs their survival, metabolism and suppressive function. To exclude the impact of excessive inflammation on LKB1-deficient Treg cells, we generated mixed bone marrow (BM) chimeras using Foxp3-Cre WT and Foxp3-Cre Stk11 fl/fl BM cells, together with CD45.1+ BM cells. We used microarray to compare the global transcription profile of dornor-derived LKB1-deficient Tregs with WT counterparts. Overall design: In total 10 samples; 5 sampels WT Treg cells and 5 samples of LKB1-deficient Treg cells
Project description:Targeting histone/protein deacetylase (HDAC)-6, -9, or Sirtuin-1 (Sirt1) augments the suppressive functions of Foxp3+ T regulatory (Treg) cells, but it is unclear if this involves different mechanisms, such that combined inhibition would be beneficial. We compared the suppressive functions of Tregs from wild-type C57BL/6 mice or mice with global (HDAC6-/-, HDAC9-/-, dual HDAC6/9-/-) or conditional deletion (CD4-Cre or Foxp3-Cre and floxed Sirt1; GSE26425) alone, or after treatment with isoform-selective HDAC inhibitors (HDACi). We found the heat shock response was crucial in mediating the effects of HDAC6, but not Sirt1 inhibition. Furthermore, while HDAC6, HDAC9 and Sirt1 all deacetylate Foxp3, each has diverse effects on Foxp3 transcription, and loss of HDAC9 is associated with stabilization of Stat5 acetylation and its transcriptional activity. Targeting different HDAC can increase Treg function by multiple and additive mechanisms, indicating the therapeutic potential for combinations of HDACi in the management of autoimmunity and alloresponses post-transplant. RNA from three independent samples of magnetically separated CD4+CD25+ Treg of HDAC9-/- mice, compared to wild type (C57BL/6) control.