Project description:We report the translational regulation of murine TFH cells, showing that they contain high levels of translation initiation factor eIF4E, which we show is essential for translation of TFH cell differentiation and function mRNAs.
Project description:Analysis of in vivo antigen-specific (LCMV-specific, SMARTA TCR transgenic) follicular helper CD4 T cells (CXCR5high),versus non-follicular helper CD4 T cells (CXCR5low), eight days after viral infection. A paper including data analysis of these experiments has been accepted for publication (Robert J. Johnston et al. Bcl6 and Blimp-1 are reciprocal and antagonistic regulators of follicular helper CD4 T cell differentiation). Experiment Overall Design: Analysis of in vivo antigen-specific (LCMV-specific, SMARTA TCR transgenic) follicular helper CD4 T cells (CXCR5high), versus non-follicular helper CD4 T cells (CXCR5low), eight days after viral infection.
Project description:Analysis of in vivo antigen-specific (LCMV-specific, SMARTA TCR transgenic) follicular helper CD4 T cells (CXCR5high),versus non-follicular helper CD4 T cells (CXCR5low), eight days after viral infection. A paper including data analysis of these experiments has been accepted for publication (Robert J. Johnston et al. Bcl6 and Blimp-1 are reciprocal and antagonistic regulators of follicular helper CD4 T cell differentiation).
Project description:T follicular helper (Tfh) cells constitute an essential cell type in the induction of antibodies. We report that CD4 T cells lacking Foxo1 almost uniformly became CXCR5int Tfh cells following immunization. Moreover, a Foxo1 loss-of-function complemented an Icos mutation allowing the appearance of Tfh cells along with follicular, class-switched B cells and IgG isotype anti-DNA antibodies. Similarly, FOXO1 deficient Tfh differentiation displayed a substantially reduced dependence on ICOSL. Functional and molecular analyses show that FOXO1 regulates Tfh differentiation through a broad program of gene expression exemplified by positive regulation of Icos and negative regulation of Bcl6. These results demonstrate that a key step in Tfh differentiation is the ICOS-initiated activation of the PI3K-AKT pathway resulting in the inactivation of FOXO1. Performed ChIP-seq analysis to examine the role of foxo1 in the development of Tfh cells
Project description:T follicular helper (TFH) cells are essential for developing protective antibody responses following vaccination. Greater understanding of the genetic program leading to TFH differentiation is needed. Chromatin modifications are central in the control of gene expression. However, detailed knowledge of how chromatin regulators (CRs) regulate differentiation of TFH cells is limited. We screened a large shRNA library targeting all known CRs in mouse and identified the histone methyltransferase Mll1 as a positive regulator of TFH differentiation. Loss of Mll1 expression reduced formation of TFH cells following acute viral infection or protein immunization. In addition, expression of the TFH lineage-defining transcription factor Bcl6 was reduced in the absence of Mll1. Transcriptomics analysis identified Lef1 and Tcf7 as genes dependent on Mll1 for their expression, which provides one mechanism for the regulation of TFH differentiation by Mll1. Taken together, CRs such as Mll1 substantially influence TFH differentiation.
Project description:To determine the role of the cytokine activin A in the regulation of human T follicular helper (Tfh) cell gene program, we performed a transcriptomic analysis (RNA-seq) of human naïve CD4 T cells differentiated in vitro with activin A. The analysis of the gene expression profile driven by activin A, alone or in combination with IL-12 (a know regulator of human Tfh differentiation/function), revealed that activin A can regulate the expression of multiple molecules involved in the differentiation and/or function of human Tfh cells.
Project description:To determine the role of the cytokine activin A in the regulation of human T follicular helper (Tfh) cell gene program, we performed a transcriptomic analysis (RNA-seq) of human naïve CD4 T cells differentiated in vitro with activin A. The analysis of the gene expression profile driven by activin A, alone or in combination with IL-12 (a know regulator of human Tfh differentiation/function), revealed that activin A can regulate the expression of multiple molecules involved in the differentiation and/or function of human Tfh cells. Human naïve CD4 T cells were isolated from fresh PBMCs of healthy control subjects by magnetic bead isolation. Purity was measured by FACS as percentage of CD4+CD45RA+ cells and was 95% or higher. Upon isolation, naïve CD4 T cells were stimulated with anti-CD3/CD28 coated beads in the presence of the following cytokine combinations: no exogenous cytokines (beads only), activin A, IL-12, activin A+IL-12, TGFb, TGFb +IL12. Following 5 days of in vitro culture, live CD4 T cells were FACS sorted and gene expression was analyzed by RNA-seq. Data are from independent donors.