Project description:Differentiation of naive CD4+ T cells into T-helper (Th) effector subsets is critical for protection against pathogens. Together, E-protein transcription factors and the inhibitor-of-DNA binding (Id) proteins are important arbiters of T cell development, but their role in the differentiation of Th1 and Tfh cells is not well understood. Th1 cells show robust Id2 expression compared to Tfh cells, and RNAi depletion of Id2 increased Tfh cell frequencies and germinal center responses, while impairing Th1 cell accumulation during viral infection. Further, Th1 cell differentiation was blocked by genetic ablation of Id2, leading to E-protein dependent accumulation of effector cells with 78% of Th1-associated genes showing diminished expression and a concurrent enrichment of the Tfh gene-expression program. The Tfh-defining transcriptional repressor Bcl6 bound to the Id2 locus inhibiting expression, providing a mechanism by which bimodal expression of Id2 in Tfh and Th1 cells can be established. Thus, Id2 is critical in enforcing the reciprocal development of Th1 and Tfh cell fates. We used microarray to assess the changes in gene expression between Id2-sufficient and -deficient Th1 and Tfh cells.
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:TFH and Th1 cells generated after viral or intracellular bacterial infections are critical for the control of infections and the development of immunological memories. However, the mechanisms that govern the choice of activated CD4 T cells to the two alternative fates remain unclear. Here, we found that reciprocal expression of TCF1 and Blimp1 between viral-specific TFH and Th1 cells started early after infection. TCF1 was intrinsically required for the differentiation of TFH cells. In the absence of TCF1, TFH cells failed to maintain their transcriptional and metabolic signatures, distinct from those in Th1 cells. Mechanistically, TCF1 functioned through forming negative feedback loops with IL-2 and Blimp1 signaling. Thus, we have demonstrated an essential role of TCF1 in TFH-cell differentiation. Tcf7 deficient and WT SMARTA CD4 T cells were isolated from mice 8 days after Lymphocytic Choriomeningitis Virus (LCMV) infection. TFH and Th1 cells were separated by FACS.
Project description:This study provides evidence on the molecular mechanisms by which P2RX7 signaling promotes Th1 cell differentiation. P2RX7 induces T-bet expression and aerobic glycolysis in splenic CD4+ T cells that respond to malaria, at a time prior to Th1/Tfh polarization. Cell-intrinsic P2RX7 signaling sustains the glycolytic pathway and causes bioenergetic mitochondrial stress in activated CD4+ T cells. We also show in vitro the phenotypic similarities of Th1-polarized CD4+ T cells that do not express P2RX7 and those in which the glycolytic pathway is pharmacologically inhibited. In addition, ATP synthase blockade in vitro and the consequent inhibition of oxidative phosphorylation, which forces cells to use aerobic glycolysis, is sufficient to promote rapid CD4+ T cell proliferation and polarization to the Th1 profile in the absence of P2RX7. These data demonstrate that P2RX7-mediated metabolic reprograming for aerobic glycolysis is a key event for Th1 cell differentiation and suggest that ATP synthase inhibition is a fundamental mechanism by which P2X7 signaling induces the Th1 response.
Project description:It is now well established that the E- and Id-protein axis regulates multiple steps in lymphocyte development. However, it remains unknown as to how E- and Id-proteins mechanistically enforce and maintain the naïve T cell fate. Here we show that Id2 and Id3 suppressed the development and expansion of innate-variant TFH cells. Innate-variant TFH cells required MHC Class I-like signalling and were associated with germinal center B cell development. We found that Id2 and Id3 induced Foxo1 and Foxp1 expression to antagonize the activation of TFH transcription signature. We show that Id2 and Id3 acted upstream of the Hif1a/Foxo/AKT/mTORC1 pathway as well as the c-myc/p19Arf module to control cellular expansion and activation. We found that mice depleted for Id2 and Id3 expression developed colitis and αβ T cell lymphomas. Lymphomas depleted for Id2 and Id3 expression displayed elevated levels of c-myc whereas p19Arf abundance declined. Transcription signatures of Id2- and Id3-depleted lymphomas revealed similarities with genetic deficiencies associated with Burkitt lymphoma. We propose that in response to antigen receptor and/or cytokine signaling the E-Id protein axis modulates the activities of the PI3K-AKT-mTORC1-Hifa and c-myc/p19Arf pathways to control cellular expansion and homeostatic proliferation. RNA-seq data of 5 of wild type CD4SP cells, 3 of wild type Tfh cells, 3 of Id3-/- CD4SP cells, 3 of Id2-/-Id3-/-(dKO) CD4SP cells, and 6 of Id2-/-Id3-/- lymphoma cells.
Project description:Following an infection, CD4+ lymphocytes can differentiate into long-lived memory T cells, some of which circulate through the secondary lymphoid organs (SLOs) while a population lodges in non-lymphoid tissues. While CD4+ T cells in SLOs have been examined, the developmental origins and transcriptional regulation of tissue-resident memory T cells (TRM) remain largely undefined. Here, we investigated the phenotypic, functional, and transcriptional profile of virus-specific CD4+ TRM in the small intestine (SI) following acute lymphocytic choriomeningitis virus (LCMV) infection. LCMV-specific CD4+ TRM at day 7 of infection shared a gene-expression program and chromatin profile with TH1 cells and progressively acquired a mature TRM program by day 21 memory time point, supporting a developmental relationship between TRM and TH1 subsets. Furthermore, we demonstrated that TRM cells expressed genes associated with both effector and memory T cell fates, including the transcriptional regulators Blimp1, Id2, and Bcl6 which were necessary for CD4+ TRM differentiation. TH1-associated Blimp1 and Id2 were both required for early TRM formation, while TFH-associated Bcl6 initially inhibited TRM differentiation but was critical for development of long-lived TRM cells. Our results identify new significance for TFs previously associated with circulating CD4+ T cell populations and their roles in driving SI CD4+ TRM differentiation.
Project description:Following an infection, CD4+ lymphocytes can differentiate into long-lived memory T cells, some of which circulate through the secondary lymphoid organs (SLOs) while a population lodges in non-lymphoid tissues. While CD4+ T cells in SLOs have been examined, the developmental origins and transcriptional regulation of tissue-resident memory T cells (TRM) remain largely undefined. Here, we investigated the phenotypic, functional, and transcriptional profile of virus-specific CD4+ TRM in the small intestine (SI) following acute lymphocytic choriomeningitis virus (LCMV) infection. LCMV-specific CD4+ TRM at day 7 of infection shared a gene-expression program and chromatin profile with TH1 cells and progressively acquired a mature TRM program by day 21 memory time point, supporting a developmental relationship between TRM and TH1 subsets. Furthermore, we demonstrated that TRM cells expressed genes associated with both effector and memory T cell fates, including the transcriptional regulators Blimp1, Id2, and Bcl6 which were necessary for CD4+ TRM differentiation. TH1-associated Blimp1 and Id2 were both required for early TRM formation, while TFH-associated Bcl6 initially inhibited TRM differentiation but was critical for development of long-lived TRM cells. Our results identify new significance for TFs previously associated with circulating CD4+ T cell populations and their roles in driving SI CD4+ TRM differentiation.
Project description:Following an infection, CD4+ lymphocytes can differentiate into long-lived memory T cells, some of which circulate through the secondary lymphoid organs (SLOs) while a population lodges in non-lymphoid tissues. While CD4+ T cells in SLOs have been examined, the developmental origins and transcriptional regulation of tissue-resident memory T cells (TRM) remain largely undefined. Here, we investigated the phenotypic, functional, and transcriptional profile of virus-specific CD4+ TRM in the small intestine (SI) following acute lymphocytic choriomeningitis virus (LCMV) infection. LCMV-specific CD4+ TRM at day 7 of infection shared a gene-expression program and chromatin profile with TH1 cells and progressively acquired a mature TRM program by day 21 memory time point, supporting a developmental relationship between TRM and TH1 subsets. Furthermore, we demonstrated that TRM cells expressed genes associated with both effector and memory T cell fates, including the transcriptional regulators Blimp1, Id2, and Bcl6 which were necessary for CD4+ TRM differentiation. TH1-associated Blimp1 and Id2 were both required for early TRM formation, while TFH-associated Bcl6 initially inhibited TRM differentiation but was critical for development of long-lived TRM cells. Our results identify new significance for TFs previously associated with circulating CD4+ T cell populations and their roles in driving SI CD4+ TRM differentiation.
Project description:Following an infection, CD4+ lymphocytes can differentiate into long-lived memory T cells, some of which circulate through the secondary lymphoid organs (SLOs) while a population lodges in non-lymphoid tissues. While CD4+ T cells in SLOs have been examined, the developmental origins and transcriptional regulation of tissue-resident memory T cells (TRM) remain largely undefined. Here, we investigated the phenotypic, functional, and transcriptional profile of virus-specific CD4+ TRM in the small intestine (SI) following acute lymphocytic choriomeningitis virus (LCMV) infection. LCMV-specific CD4+ TRM at day 7 of infection shared a gene-expression program and chromatin profile with TH1 cells and progressively acquired a mature TRM program by day 21 memory time point, supporting a developmental relationship between TRM and TH1 subsets. Furthermore, we demonstrated that TRM cells expressed genes associated with both effector and memory T cell fates, including the transcriptional regulators Blimp1, Id2, and Bcl6 which were necessary for CD4+ TRM differentiation. TH1-associated Blimp1 and Id2 were both required for early TRM formation, while TFH-associated Bcl6 initially inhibited TRM differentiation but was critical for development of long-lived TRM cells. Our results identify new significance for TFs previously associated with circulating CD4+ T cell populations and their roles in driving SI CD4+ TRM differentiation.
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.