Project description:A better understanding of the mechanisms regulating CD8+ T cell differentiation is essential to develop new strategies to fight infections and cancer. Using genetic mouse models and blocking antibodies, we uncovered cellular and molecular mechanisms by which Notch signaling favors efficient generation of effector CD8+ T cells. Using transcriptional and epigenetic studies, we identified a unique Notch-driven T cell-specific signature. Early Notch signals were associated with chromatin opening in regions occupied by bZIP transcription factors, specifically BATF, known to be important for CD8+ T cell differentiation. Overall, we show that the delivery of early Notch signals controls the molecular and functional fate of CD8+ T cells after infection.
Project description:A better understanding of the mechanisms regulating CD8+ T cell differentiation is essential to develop new strategies to fight infections and cancer. Using genetic mouse models and blocking antibodies, we uncovered cellular and molecular mechanisms by which Notch signaling favors efficient generation of effector CD8+ T cells. Using transcriptional and epigenetic studies, we identified a unique Notch-driven T cell-specific signature. Early Notch signals were associated with chromatin opening in regions occupied by bZIP transcription factors, specifically BATF, known to be important for CD8+ T cell differentiation. Overall, we show that the delivery of early Notch signals controls the molecular and functional fate of CD8+ T cells after infection.
Project description:Phosphatidylinositol-3-kinase p110 delta (PI3Kp110δ) is pivotal for CD8+ T cell immune responses. To inform how PI3Kp110δ regulates CD8+ T cells, the current study focuses on PI3Kp110δ controlled transcriptional programs and reveals how PI3Kp110δ selectively induces and represses expression of key genes that create a cytotoxic T cell (CTL). The data identify differences in PI3Kp110δ regulated transcriptional programs between naïve and cytotoxic T cells including differential control of cytolytic effector molecules, costimulatory receptors and the critical inhibitory receptors CTLA4 and SLAMF6. However, common to both naïve and effector cells is PI3Kp110δ control of the production of chemokines and cytokines that orchestrate communication between the adaptive and innate immune system. The study provides a comprehensive resource for understanding how PI3Kp110δ uses multiple mechanisms dependent on Protein Kinase B/AKT, FOXO1 dependent and independent mechanisms and mitogen-activated protein kinases (MAPK) to direct CD8+ T cell fate.
Project description:Phosphatidylinositol-3-kinase p110 delta (PI3Kp110δ) is pivotal for CD8+ T cell immune responses. To inform how PI3Kp110δ regulates CD8+ T cells, the current study focuses on PI3Kp110δ controlled transcriptional programs and reveals how PI3Kp110δ selectively induces and represses expression of key genes that create a cytotoxic T cell (CTL). The data identify differences in PI3Kp110δ regulated transcriptional programs between naïve and cytotoxic T cells including differential control of cytolytic effector molecules, costimulatory receptors and the critical inhibitory receptors CTLA4 and SLAMF6. However, common to both naïve and effector cells is PI3Kp110δ control of the production of chemokines and cytokines that orchestrate communication between the adaptive and innate immune system. The study provides a comprehensive resource for understanding how PI3Kp110δ uses multiple mechanisms dependent on Protein Kinase B/AKT, FOXO1 dependent and independent mechanisms and mitogen-activated protein kinases (MAPK) to direct CD8+ T cell fate.
Project description:DNMT3a is a de novo DNA methyltransferase expressed robustly after T cell activation that regulates plasticity of CD4+ T cell cytokine expression. Here we show that DNMT3a is critical for directing early CD8+ T cell effector and memory fate decisions. While effector function of DNMT3a knockout T cells is normal, they develop more memory precursor and fewer terminal effector cells in a T cell intrinsic manner compared to wild-type animals. Rather than increasing plasticity of differentiated effector CD8+ T cells, loss of DNMT3a biases differentiation of early effector cells into memory precursor cells. This is attributed in part to ineffective repression of Tcf1 expression in knockout T cells, as DNMT3a localizes to the Tcf7 promoter and catalyzes its de novo methylation in early effector WT CD8+ T cells. This data identifies DNMT3a as a crucial regulator of CD8+ early effector cell differentiation and effector versus memory fate decisions. Examination of global genomic DNA methylation by MBD-seq in naïve CD8 T cells and CD8 T cells 8 days post Vaccinia-Ova infection, comparing OT1 TCR-Tg CD8 T cells isolated from WT and T cell conditional DNMT3a KO mice.
Project description:Antigen-specific effector CD8+ T cells deficient in Blimp-1 (Prdm1) do not acquire maximal effector functions, evade terminal differentiation, and more rapidly acquire some hallmark properties of memory CD8+ T cells. In this study, we compared the gene expression profiles of wildtype and Prdm1-/- LCMV-specific effector CD8+ T cells to better understand the molecular mechanisms underlying this striking phenotype. DNA microarray analysis was performed of DbGP33-41 and DbNP396-404 tetramer-positive effector CD8+ T cells FACS-sorted at day 8 post-LCMV infection from four independent samples of either Blimp-1 conditional knockout mice (CKO; Blimp-1flox/flox x GranzymeB-cre+) or wildtype (WT) littermate controls.
Project description:T cell dysfunctionality prevents clearance of chronic infections and cancer. Furthermore, epigenetic programming in dysfunctional CD8+ T cells limits durable responses to T cell-based immunotherapies, including immune checkpoint blockade (ICB). However, major gaps concern how upstream signals drive acquisition of dysfunctional epigenetic programs, and whether therapeutically targeting these signals can remodel terminally dysfunctional T cells to an ICB-responsive state. Here, we use an in vitro model of human T cell dysfunction and complementary in vivo mouse chronic virus infection and tumor models. We show that post-effector TGFβ1 signaling establishes terminal dysfunction in human CD8+ T cells through stable epigenetic changes. Importantly, we demonstrate that promoting BMP signaling while blocking TGFβ1 restored effector and memory programs in dysfunctional human CD8+ T cells, induced superior anti-tumor activity, and boosted ICB responses during mouse chronic virus infection. Thus, rebalancing TGFβ1/BMP-signals in dysfunctional CD8+ T cells provides an exciting new approach to enhance T cell immunotherapies.
Project description:T cell dysfunctionality prevents clearance of chronic infections and cancer. Furthermore, epigenetic programming in dysfunctional CD8+ T cells limits durable responses to T cell-based immunotherapies, including immune checkpoint blockade (ICB). However, major gaps concern how upstream signals drive acquisition of dysfunctional epigenetic programs, and whether therapeutically targeting these signals can remodel terminally dysfunctional T cells to an ICB-responsive state. Here, we use an in vitro model of human T cell dysfunction and complementary in vivo mouse chronic virus infection and tumor models. We show that post-effector TGFβ1 signaling establishes terminal dysfunction in human CD8+ T cells through stable epigenetic changes. Importantly, we demonstrate that promoting BMP signaling while blocking TGFβ1 restored effector and memory programs in dysfunctional human CD8+ T cells, induced superior anti-tumor activity, and boosted ICB responses during mouse chronic virus infection. Thus, rebalancing TGFβ1/BMP-signals in dysfunctional CD8+ T cells provides an exciting new approach to enhance T cell immunotherapies.
Project description:Transcriptome analyses of naive, effector and memory CD8 TCRP1A lymphocytes expressing or not an active form of the transcription factor Stat5. TCRP1A CD8 T lymphocytes were activated by their cognate Ag for 72h to induce their differentiation in effector T cells (TCRP1A eTL 72h: 4 replicates S1, S2, S3, S4). In some samples, an active form of Stat5 was introduced (TCRP1A Stat5ca eTL 72h: 2 replicates S9, S10). These 72h activated T cells were either purified and analyzed directly (samples mentioned above) or injected in congeneic hosts and recovered more than 20 days later from the host spleen and lymph nodes: TCRP1A eTL >d20: 2 replicates– S30, S32; TCRP1A Stat5ca eTL >d20: 4 replicates S11, S12, S13, S14). Naive TCRP1A CD8 T lymphocytes (TCRP1A-naive: 4 replicates S33, S34, S35, S36) are included as controls. TCRP1A CD8 T lymphocytes were activated by anti-CD3/CD28. After 24h, an active form of Stat5 was introduced in activated cells. Culture was continued for another 48h to induce their differentiation in effector T cells. These 72h activated T cells were either directly injected in congeneic hosts and recovered more than 14 days later from the host spleen and lymph nodes: T-BetKO Stat5ca >d14: 3 replicates S39, S40, S41.