Genome-wide identification of functional elements regulated by T-bet and GATA3 in human T-cells
ABSTRACT: T-bet and GATA3 induce differentiation of CD4+ T-cells into Th1 or Th2 effectors. These exhibit a range of different properties but understanding of T-bet and GATA3 function is mostly limited to the murine Ifng and Il4/Il5/Il13 loci. We hypothesised that extending such analyses across the human genome would allow further insight into T-bet and GATA3 function. We have discovered that T-bet and GATA3 bind to multiple distal sites at a set of key immune regulatory genes. These sites display markers of functional elements, act as enhancers in reporter assays and are associated with lineage-specific expression regulated by T-bet and GATA3. Our approach also reveals that GATA3 is distributed at T-bet binding sites in Th1 cells and that T-bet directly activates its own expression. We propose that these aspects of T-bet and GATA3 function are critical for Th1/ Th2 differentiation and provide a model for the relationship between other lineage-specific regulators. ChIP was performed using antibody against T-bet in Th1 cells and against GATA3 in Th1 cells as well as Th2 cells. A sample of whole cell extract (WCE) from Th1 cells and Th2 cells was sequenced. Th1 WCE was used as the background to determine enrichment.
Project description:Although lincRNAs are implicated in regulating gene expression in various tissues, little is known about lincRNA transcriptomes in the T cell lineages. Here we identify 1,524 lincRNAs in 42 T cell samples from early T cell progenitors to terminally differentiated T helper subsets. Our analysis revealed highly dynamic and cell-specific expression patterns of lincRNAs during T cell differentiation. Importantly, these lincRNAs are located in genomic regions enriched for protein-coding genes with immune-regulatory functions. Many of these transcripts are bound and regulated by the key T cell transcription factors, T-bet, GATA3, STAT4 and STAT6. We demonstrate that the lincRNA LincR-Ccr2-5'AS, together with GATA3, is an essential component of a regulatory circuit in Th2-specific gene expression. To obtain comprehensive profiles of lincRNA expression during the development and differentiation of T cell lineages, we purified CD4-CD8 double negative (DN) cells (DN1, DN2, DN3 and DN4), double positive (DP) cells (CD4+CD8+CD3low and CD4+CD8intCD69+), single positive (SP) CD4 and CD8 cells, and thymic-derived regulatory T cells (tTreg) from thymi of C57BL/6 mice. Additionally, we obtained Th1, Th2, Th17 and iTreg cells by in vitro differentiation of naïve CD4 T cells for a various length of time in culture (4 hrs, 8 hrs, 12 hrs, 24 hrs, 48 hrs, 72 hrs, 1 week, 2weeks). Total and/or polyadenylated RNAs from these cells was analyzed using RNA-Seq. To understand the regulation of lincRNAs by T cell master regulator T-bet, we compared the transcriptiomes between T-bet deficient Th1 cells and control Th1 cells. We did similar experiments and data analysis for STAT4 (Th1), GATA3 (Th2) and STAT6 (Th2). Finally, to address the funcation of a Th2-specifically expressed lincRNA, lincR-Ccr2-5'AS, we compared the transcriptomes between lincR-Ccr2-5'AS knockdown Th2 cells and control Th2 cells.
Project description:Differentiation of naive CD4 T cells into type 2 helper (Th2) cells is accompanied by chromatin remodeling and increased expression of a set of Th2-specific genes including those encoding Th2 cytokines. IL-4-mediated STAT6 activation induces high levels of transcription of GATA3, a master regulator of Th2 cell differentiation, and enforced expression of GATA3 induces Th2 cytokine expression. However, it remains unclear whether the expression of other Th2-specific genes is induced directly by GATA3. A genome-wide unbiased ChIP-seq analysis revealed that GATA3 bound to 1,279 genes selectively in Th2 cells, and 101 genes in both Th1 and Th2 cells. Simultaneously, we identified 26 highly Th2-specific STAT6-dependent inducible genes by a DNA microarray analysis-based three-step selection processes, and among them 17 genes showed GATA3 binding. We assessed dependency on GATA3 for the transcription of these 26 Th2-specific genes, and 10 genes showed increased transcription in a GATA3-dependent manner while 16 genes showed no significant responses. The transcription of the 16 GATA3-nonresponding genes was clearly increased by the introduction of an active form of STAT6, STAT6VT. Therefore, although GATA3 has been recognized as a master regulator of Th2 cell differentiation, many Th2-specific genes are not regulated by GATA3 itself but in collaboration with STAT6. Th1 and Th2 subsets are profiled for mRNA expression Examination of GATA3-binding and 3 different histone modifications in Th1 and Th2 cells.
Project description:T-bet is a critical transcription factor for T helper 1 (Th1) cell differentiation. To study the regulation and functions of T-bet, we developed a T-bet-ZsGreen reporter mouse strain, in which GFP faithfully reflects the expression of T-bet. By using this tool, we report that signals elicited by IL-12 and IFNg are redundant in inducing T-bet in mice infected with Toxoplasma gondii and that T-bet does not contribute to its own expression when induced by IL-12 and IFNg. While both T-bet and Stat4 are critical for IFNg production, IFNg signaling is dispensable. Strikingly, loss of T-bet results in activation of an endogenous Th2 program in cells expressing T-bet-ZsGreen. Genome-wide analyses suggest T-bet directly induces Th1-related genes but indirectly suppresses Th2-related genes. Our study revealed redundancy and synergy among several Th1-inducing pathways in regulating the expression of T-bet and IFNg, and a critical role of T-bet in suppressing an endogenous Th2 program. RNA-Seq experiments were performed using total RNAs isolated from both wild type and Tbx21-/- Th1 cells in duplicates. Tbet ChIP-seq was performed using wild type Th1 cells. H3K4me1 and H3K27me3 ChIP-seq was performed using both wild type and Tbx21-/- Th1 cells.
Project description:For the purpose of the Gene Regulatory Network validation we have performed chromatin-immunoprecipitation sequencing (ChIP-Seq) experiment for three transcription factors; namely GATA3, MAF and MYB. ChIP-Seq of GATA3, MAF and MYB in human naïve CD4+ T-cells differentiated toward Th1 and Th2 until day 6. Matched INPUT samples were also sequenced for each condition.
Project description:Following antigen encounter by CD4 T cells, polarizing cytokines induce the expression of master regulators that control differentiation. Inactivation of the histone methyltransferase Ezh2 was found to specifically enhance T-helper (Th)1 and Th2 cell differentiation and plasticity. Ezh2 directly bound and facilitated correct expression of Tbx21 and Gata3 in differentiating Th1 and Th2 cells, accompanied by substantial tri-methylation at lysine 27 of histone 3 (H3K27-Me3). In addition, Ezh2 deficiency resulted in spontaneous generation of discrete IFN-γ and Th2 cytokine-producing populations in non-polarizing cultures, and under these conditions IFN-γ expression was largely dependent on enhanced expression of the transcription factor Eomesodermin. In vivo, Loss of Ezh2 caused increased pathology in a model of allergic asthma and resulted in progressive accumulation of memory phenotype Th2 cells. This study establishes a functional link between Ezh2 and transcriptional regulation of lineage-specifying genes in terminally differentiated CD4 T cells. Examination of Ezh2 binding in Th1 and Th2 cells.
Project description:Differentiation of naïve CD4+ T cells into effector (Th1, Th2 and Th17) and induced regulatory (iTreg) T cells requires lineage-specifying transcription factors and epigenetic modifications that allow appropriate repression or activation of gene transcription. The epigenetic silencing of cytokine genes is associated with the repressive H3K27 trimethylation mark, mediated by Ezh2 or Ezh1 methyltransferase components of the polycomb repressive complex 2 (PRC2). EZH2 over-expression and activating mutations are implicated in tumorigenesis and correlate with poor prognosis in several tumor types 35. This spurred the development of EZH2 inhibitors which, by inducing tumor cell growth arrest and cell death, show therapeutic promise in cancer. A role for Ezh2 in suppressing Th1 and Th2 cytokine production and survival has recently been reported. It is not entirely clear whether Ezh2-PRC2 plays a role in H3K27me3 in cytokine loci in naïve CD4+ T cells and whether H3K27me3 has a non-redundant role in T helper cell lineage differentiation and survival. Here, we investigate the effects of T cell-specific Ezh2 deletion to determine the role that Ezh2-PRC2 plays in regulating the fate of differentiating naïve CD4+ T cells. Loss of Ezh2 altered the expression of 1328 genes in Th0 and 1979 genes in iTreg cells. Gene expression changes were positively correlated in both cell types, indicating that Ezh2 targets similar genes in these cells. As expected, Ifng was one of the genes most increased in expression by following loss of Ezh2. In addition, expression of Tbx21 homolog Eomes, a transcription factor that regulates IFNG production, was also significantly increased. We then performed H3K27me3 ChIP-seq on Ezh2fl/fl and Ezh2fl/fl.CD4Cre Th0 cells. Consistent with cellular phenotype and RNA-seq data, we observed a loss of the H3K27me3 at Eomes, Il4 and Il10 loci . Very low levels of H3K27me3 marks were present at Ifng and Tbx21 loci in differentiated Ezh2fl/fl Th0 cells, suggesting that upon differentiation, upregulation or activation of transcription factors accounts for IFNG overproduction. A significant loss of H3K27me3 was observed >2kb upstream of Gata3 locus , however this did not result in increased transcription . Of the 22381 genes tested for changes in H3K27me3, 1360 showed a statistically significant decrease in Ezh2fl/fl.CD4Cre Th0 cells, compared to wildtype. Furthermore, 404 of these genes also showed a concomitant gain in expression in Ezh2fl/fl.CD4Cre Th0 cells, suggesting that these loci are likely direct Ezh2-PRC2 targets. There are 3 biological replicates each of Ezh2fl/fl.CD4Cre and Ezh2fl/fl in both Th0 and iTreg cells for the RNA-seq experiment. There are 2 biological replicates each of Ezh2fl/fl.CD4Cre and Ezh2fl/fl in Th0 cells for the ChIP-seq experiment.
Project description:The transcription factor T-bet directs Th1 cell differentiation, but the molecular mechanisms that underlie this lineage-specific gene regulation are not completely understood. Here, we show that T-bet acts through super-enhancers in human and mouse Th1 cells to recruit Mediator and P-TEFb in the form of the super elongation complex (SEC). Th1-specific genes are poised in Th2 cells while T-bet-mediated recruitment of P-TEFb in Th1 cells activates transcriptional elongation. P-TEFb is recruited to both genes and super-enhancers, where it activates enhancer RNA transcription. P-TEFb inhibition and Mediator and SEC knockdown selectively block activation of T-bet target genes and P-TEFb inhibition abrogates Th1-associated experimental autoimmune uveitis. T-bet activity is independent of changes in NF-κB RelA and Brd4 binding, but T-bet- and NF-κB-mediated pathways converge to allow P-TEFb recruitment. These data support a model in which lineage-specifying factors allow recruitment of P-TEFb to poised genes to promote differentiation of alternative T cell fates. Overall design: Indentification of P-TEFb binding sites in human Th1 and Th2 cells Indentification of RelA binding sites in human Th1 cells treated with BAY 11-7082 and DMSO control Indentification of P-TEFb binding sites in human Th1 cells treated with BAY 11-7082 and DMSO control Indentification of AFF4 binding sites in human Th1 cells treated with BAY 11-7082 and DMSO control Indentification of BRD4 binding sites in human Th1 cells treated with BAY 11-7082 and DMSO control Indentification of MED1 binding sites in human Th1 cells treated with BAY 11-7082 and DMSO control Indentification of P-TEFb binding sites in mouse wild-type and T-bet -/- Th1 and wild-type Th2 cells Indentification of RelA binding sites in mouse wild-type and T-bet -/- Th1 cells Indentification of Brd4 binding sites in mouse wild-type and T-bet -/- Th1 cells Indentification of Med1 binding sites in mouse wild-type and T-bet -/- Th1 cells Indentification of Aff4 binding sites in mouse wild-type and T-bet -/- Th1 cells Indentification of P-TEFb binding sites in EL4-GFP and EL4-T-bet cells Indentification of Flag-T-bet binding sites in EL4-T-bet-mPlum and EL4-Gata3-GFP cells Indentification of RelA binding sites in EL4-GFP and EL4-T-bet cells Indentification of Brd4 binding sites in EL4-GFP and EL4-T-bet cells Indentification of Med1 binding sites in EL4-GFP and EL4-T-bet cells Indentification of Aff4 binding sites in EL4-GFP and EL4-T-bet cells Indentification of RNA polymerase II binding sites in human Th1 and Th2 cells Mapping of H3K4me3 histone modifications in human Th1 and Th2 cells Mapping of H3K4me3 histone modifications in human CCR5+ memory Th1 Mapping of H3 histone in human CCR5+ memory Th1 Mapping of H3K27ac histone modifications in human Th1 and Th2 cells Mapping of H3K4me3 histone modifications in mouse wild-type and T-bet-/- Th1 cells Mapping of H3 histone in mouse wild-type and T-bet-/- Th1 cells
Project description:Functionally polarized CD4+ T helper (Th) cells such as Th1, Th2 and Th17 cells are central to the regulation of acquired immunity. However, the molecular mechanisms governing the maintenance of the polarized functions of Th cells remain unclear. GATA3, a master regulator of Th2 cell differentiation, initiates the expressions of Th2 cytokine genes and other Th2-specific genes. GATA3 also plays important roles in maintaining Th2 cell function and in continuous chromatin remodeling of Th2 cytokine gene loci. However, it is unclear whether continuous expression of GATA3 is required to maintain the expression of various other Th2-specific genes. In this report, genome-wide DNA gene expression profiling revealed that GATA3 expression is critical for the expression of a certain set of Th2-specific genes. We demonstrated that GATA3 dependency is reduced for some Th2-specific genes in fully developed Th2 cells compared to that observed in effector Th2 cells, whereas it is unchanged for other genes. Moreover, effects of a loss of GATA3 expression in Th2 cells on the expression of cytokine and cytokine receptor genes were examined in detail. A critical role of GATA3 in the regulation of Th2-specific gene expression is confirmed in in vivo generated antigen-specific memory Th2 cells. Therefore, GATA3 is required for the continuous expression of the majority of Th2-specific genes involved in maintaining the Th2 cell identity. Mock-transfected and GATA3 siRNA-transfected Th2 and Th2-4th cells are profiled for mRNA expression
Project description:T helper (Th) cells control host defense to pathogens. IL 12R expression is required for Th1, IL-4Rα for Th2, and IL-6Rα/gp130 for Th17 differentiation to allow responsiveness to IL-12, IL-4, and IL-6, respectively. IL-2 via STAT5 controls Th2 differentiation by regulating the Th2 cytokine gene cluster and Il4ra expression. Here we show that IL-2 regulates Th1 differentiation, inducing STAT5-dependent IL-12Rβ2 and T-bet expression, with impaired human Th1 differentiation when IL-2 was blocked. Th1 differentiation was also impaired in mouse Il2-/- T cells but restored by IL-12Rβ2 expression. Consistent with IL-2’s inhibition of Th17 differentiation, IL-2 decreased Il6ra and Il6st/gp130 expression, and Il6st augmented Th17 differentiation even when IL-2 was present. Thus, IL-2 influences T-cell differentiation by modulating cytokine receptor expression to help specify/maintain differentiated states. Genome-wide mapping of STAT1,STAT4,STAT5A,STAT5B binding to their target genes in Th1 or human CD4+ cells was conducted