Project description:Ets1 can directly bind key TFH genes, regulating their expression . Loss of Ets1 results in the pre-mature expression of TFH-genes in Non-TFH cells. We wished to analyze if loss of Ets1 correlated with changes in chromatin accessibility especially in TFH gene loci.
Project description:To characterize the effect of loss of Ets1 in Non-TFH and TFH cells, we performed gene expression RNAseq analysis for T follicular helper (TFH) and Non-T follicular helper (Non-TFH) cells in WT (Ets1 fl/fl) and Ets1 KO (CD4-cre Ets1 fl/fl) mice.
Project description:Follicular helper T (Tfh) cells access the B cell follicle to promote antibody responses, and are particularly important for germinal center (GC) reactions. However, the molecular mechanisms of how Tfh cells are physically associated with GCs are incompletely understood. Here we report that the sphingosine-1-phosphate receptor 2 (S1PR2) gene is highly expressed in a subpopulation of Tfh cells that localizes in GCs. S1PR2-deficient Tfh cells exhibited reduced accumulation in GCs due to their impaired retention. T cells deficient in both S1PR2 and CXCR5 were ineffective in supporting GC responses compared to T cells deficient only in CXCR5. These results suggest that S1PR2 and CXCR5 cooperatively regulate localization of Tfh cells in GCs to support GC responses. Venus-high Tfh, Venus-low Tfh, PD1-intermediate Th, PD1-low Th and naïve CD4+ T cells were sorted on FACSAria from immunized S1pr2V/+ mice or control mice for RNA extraction and hybridization on Affimetrix microarrays.
Project description:We found that a number of Tfh cells downmodulated BCL6 protein after their development, and we sought to compare the gene expression between BCL6-hi Tfh cells and BCL6-low Tfh cells. CD4+ T cells were sorted from immunized and non-immunized mice for RNA extraction and hybridization on Affymetrix microarrays. Bcl6yfp/+ OT-II cells were transferred to congenic recipient mice, and immunized with NP-OVA in CFA subcutaneously. Seven or ten days after immunization, cells were collected from draining lymph nodes, and sorted on FACSAria by the expression of CXCR5, PD-1 and BCL6-YFP. Naive CD4+ T cells were CD4+ CD44lo CD62Lhi cells from unimmunized mice.
Project description:ATAC-Seq experiments were performed to elucidate the chromatin state changes among naïve CD4+ T cells, WT follicular helper T (TFH) cells and WT type 1 helper T (TH1) cells Day2 (D2), Day5 (D5), Day8 (D8) post-LCMV-Armstrong infection, as well as EZH2-null (KO) TFH and TH1 at Day8 post-LCMV-infection. The analysis suggested stringent lineage-specific mode of chromatin accessibility in each group, indicating chromatin remodeling is tightly associated with TFH versus TH1 lineage differentiation in response to acute viral infection. Furthermore, the comparison between wild-type and EZH2-null TFH cells showed that less-opening state of certain chromatin accessible region in TFH-differentiation associated genes in the formers, suggesting EZH2 led to permissive chromatin accessibility primarily at specific regions of TFH-associated genes. H3K27me3-ChIP-seq was performed in WT TFH and TH1 cells to confirm the deposition of the histone marks at those loci.
Project description:We found that a number of Tfh cells downmodulated BCL6 protein after their development, and we sought to compare the gene expression between BCL6-hi Tfh cells and BCL6-low Tfh cells.
Project description:CD4 T cell help is critical for both the generation and maintenance of germinal centers, and T follicular helper (TFH) cells are the CD4 T cell subset required for this process. SAP (SH2D1A) expression in CD4 T cells is essential for germinal center development. However, SAP-deficient mice have only a moderate defect in TFH differentiation as defined by common TFH surface markers. CXCR5+ TFH cells are found within the germinal center as well as along the boundary regions of T/B cell zones. Here we show that germinal center associated T cells (GC TFH) can be identified by their co-expression of CXCR5 and the GL7 epitope, allowing for phenotypic and functional analysis of TFH and GC TFH populations. Here we show GC TFH are a functionally discrete subset of further polarized TFH cells, with enhanced B cell help capacity and a specialized ability to produce IL-4 in a TH2-independent manner. Strikingly, SAP-deficient mice have an absence of the GC TFH subset and SAP- TFH are defective in IL-4 and IL-21 production. We further demonstrate that SLAM (Slamf1, CD150), a surface receptor that utilizes SAP signaling, is specifically required for IL-4 production by GC TFH. GC TFH cells require IL-4 and IL-21 production for optimal help to B cells. These data illustrate complexities of SAP-dependent SLAM family receptor signaling, revealing a prominent role for SLAM receptor ligation in IL-4 production by germinal center CD4 T cells but not in TFH and GC TFH differentiation. Analysis of in vivo polyclonal GC Tfh vs Tfh vs Non-Tfh eight days after LCMV viral infection. Analysis of in vivo follicular helper CD4 T cells (CXCR5high GL7low), versus germinal center follicular helper CD4 T cells (CXCR5hi GL7hi), versus non-follicular helper CD4 T cells (CXCR5low) eight days after viral infection.