STAT4 and T-bet control follicular helper T cells development in viral infections [ATAC-seq]
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ABSTRACT: Follicular helper T (Tfh) cells promote germinal center (GC) B cell survival and proliferation, and guide their differentiation and Ig isotype switching by delivering contact-dependent and soluble factors, including IL-21, IL-4, IL-9, and IFN-g. IL-21 and IFN-g are co-expressed by Tfh cells during acute and chronic infections, but transcriptional regulation of these cytokines in the GC is incompletely understood. We show that the Th1 transcriptional regulators T-bet and STAT4 are co-expressed with Bcl6 in Tfh cells following acute murine lymphocytic choriomeningitis virus infection, albeit with temporal decline in T-bet expression as the GC response evolved. T-bet was important for Tfh cell production of IFN-g, but not IL-21, and for the generation of a robust germinal center reaction. STAT4, phosphorylated in Tfh cells upon infection, was required for their expression of T-bet and Bcl6, and that of IFN-g and IL-21. These data indicate that T-bet is concomitantly expressed with Bcl6 in Tfh cells and is required alongside STAT4 phosphorylation to coordinate Tfh cell IL-21 and IFN-g production, and for promotion of the GC response following acute viral challenge.
Project description:Follicular helper T (Tfh) cells promote germinal center (GC) B cell survival and proliferation, and guide their differentiation and Ig isotype switching by delivering contact-dependent and soluble factors, including IL-21, IL-4, IL-9, and IFN-g. IL-21 and IFN-g are co-expressed by Tfh cells during acute and chronic infections, but transcriptional regulation of these cytokines in the GC is incompletely understood. We show that the Th1 transcriptional regulators T-bet and STAT4 are co-expressed with Bcl6 in Tfh cells following acute murine lymphocytic choriomeningitis virus infection, albeit with temporal decline in T-bet expression as the GC response evolved. T-bet was important for Tfh cell production of IFN-g, but not IL-21, and for the generation of a robust germinal center reaction. STAT4, phosphorylated in Tfh cells upon infection, was required for their expression of T-bet and Bcl6, and that of IFN-g and IL-21. These data indicate that T-bet is concomitantly expressed with Bcl6 in Tfh cells and is required alongside STAT4 phosphorylation to coordinate Tfh cell IL-21 and IFN-g production, and for promotion of the GC response following acute viral challenge.
Project description:Follicular helper T (Tfh) cells comprise an important subset of helper T cells; however, their relationship with other helper lineages is incompletely understood. Herein, we show IL-12 acting via signal transducer and activator of transcription 4 (STAT4) induced both Il21 and Bcl6 genes, generating cells with features of both Tfh and Th1 cells. However, STAT4 also induced T-bet. Using ChIP-seq, we defined the genome-wide targets of T-bet and found that it repressed Bcl6 and other markers of Tfh cells, thereby attenuating the nascent Tfh-like phenotype in the late phase of Th1 specification. Finally, Tfh-like T cells were rapidly generated following Toxoplasma gondii infection in mice, but T-bet constrained Tfh cells expansion and consequent germinal center formation and antibody production. Our data argue that Tfh and Th1 share a transitional stage through the signal mediated by STAT4, which promotes both phenotypes. However, T-bet represses Tfh functionalities, promoting full Th1 differentiation. The roles of STAT4 and T-bet to determine T helper cell fate were investigated by comparing DNA binding profiles of STAT4 and T-bet in Th1 conditions. The functional outcome was further evaluated by profiling DNase hypersensitivity sites and histone epigenetic marks between WT and STAT4-deficient or T-bet-deficient T cells in Th1 conditions.
Project description:Follicular helper T (Tfh) cells comprise an important subset of helper T cells; however, their relationship with other helper lineages is incompletely understood. Herein, we show IL-12 acting via signal transducer and activator of transcription 4 (STAT4) induced both Il21 and Bcl6 genes, generating cells with features of both Tfh and Th1 cells. However, STAT4 also induced T-bet. Using ChIP-seq, we defined the genome-wide targets of T-bet and found that it repressed Bcl6 and other markers of Tfh cells, thereby attenuating the nascent Tfh-like phenotype in the late phase of Th1 specification. Finally, Tfh-like T cells were rapidly generated following Toxoplasma gondii infection in mice, but T-bet constrained Tfh cells expansion and consequent germinal center formation and antibody production. Our data argue that Tfh and Th1 share a transitional stage through the signal mediated by STAT4, which promotes both phenotypes. However, T-bet represses Tfh functionalities, promoting full Th1 differentiation.
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.
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. This SuperSeries is composed of the following subset Series: GSE21379: Expression Data from WT and Sh2d1a-/- in vivo follicular helper CD4 T cells (TFH) versus non follicular helper CD4 T cells (non-TFH) GSE21380: Expression Data from in vivo Tfh vs GC Tfh vs non-Tfh Refer to individual Series
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 antigen-specific (LCMV-specific, SMARTA TCR transgenic) WT and Sh2d1a-/- follicular helper CD4 T cells (CXCR5high),versus non-follicular helper CD4 T cells (CXCR5low), eight days after viral infection.
Project description:Follicular T helper cells (Tfh) are critical for providing help to B cells for germinal center (GC) formation. Mutations affecting SAP prevent GC formation due to defective T:B cell interactions, yet effects on Tfh cell differentiation remain unclear. We describe the in vitro differentiation of functionally competent “Tfh-like” cells that expressed IL-21, Tfh markers, and Bcl6, and rescued GC formation in SAP-deficient hosts substantially better than other T helper (Th) cells. SAP-deficient Tfh-like cells appeared virtually indistinguishable from wildtype, yet failed to support GCs in vivo. Interestingly, both Tfh-like and in vivo-derived Tfh cells could produce effector cytokines in response to polarizing conditions. Moreover, other Th cell populations could be reprogrammed to obtain Tfh characteristics. ChIP-Seq analyses revealed positive epigenetic markings on Tbx21, Gata3 and Rorc in Tfh-like and ex vivo Tfh cells, and Bcl6 in other Th cells, supporting the concept of plasticity between Tfh and other Th populations. We describe the in vitro differentiation of functionally competent IL-21-producing cells with Tfh-like properties. Importantly, transfer of low numbers of these cells induced GC formation in SAP-deficient hosts more effectively than other in vitro differentiated Th cells, suggesting they represent bona fide Tfh cell precursors. We have chosen the name “Tfh-like” cells for these in vitro differentiated IL-21 producing cells as they exhibit Tfh characteristics, but do not reside within B cell follicles. SAP-deficient Tfh-like cells were virtually indistinguishable from WT, yet nonetheless, failed to effectively contribute to Tfh cells and rescue GC formation in vivo. Evaluation of cytokine production as well as epigenetic chromatin modifications of genes encoding Th cell-specific transcription factors from either in vitro-generated Tfh-like cells or Tfh cells isolated directly ex vivo provided evidence for plasticity between Tfh-like and other Th cell populations. Our results provide insight into the requirements for differentiation and plasticity of Tfh cells, which are critical for the generation of effective long-term humoral immunity. RNA was prepared from subconfluent asynchronously proliferating cells using TRIZOL and purified by RNeasy MinElute Cleanup kit (Qiagen). Hybridization to Affymetrix GeneChip Mouse Genome 430 2.0 arrays was used to generate gene expression profiles of WT Tfh-like and SAP-deficient Tfh-like 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.
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.
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. This SuperSeries is composed of the SubSeries listed below.