Project description:CD8+ T cells are pre-programmed for cytotoxic differentiation. However, a subset of effector CD8+ T cells (‘Tc17’) produce IL-17 and fail to express cytotoxic genes. Here, we show that the transcription factors directing IL-17 production inhibit cytotoxicity despite persistent Runx3 expression. Cytotoxic gene repression did not require the transcription factor Thpok. We further show that STAT3 restrained cytotoxic gene expression in CD8+ T cells and that RORgt represses cytotoxic genes by inhibiting the functions but not the expression of the ‘cytotoxic’ transcription factors T-bet and Eomesodermin. Thus, the transcriptional circuitry directing IL-17 expression inhibits cytotoxic functions.
Project description:CD8+ T cells are pre-programmed for cytotoxic differentiation. However, a subset of effector CD8+ T cells (‘Tc17’) produce IL-17 and fail to express cytotoxic genes. Here, we show that the transcription factors directing IL-17 production inhibit cytotoxicity despite persistent Runx3 expression. Cytotoxic gene repression did not require the transcription factor Thpok. We further show that STAT3 restrained cytotoxic gene expression in CD8+ T cells and that RORgt represses cytotoxic genes by inhibiting the functions but not the expression of the ‘cytotoxic’ transcription factors T-bet and Eomesodermin. Thus, the transcriptional circuitry directing IL-17 expression inhibits cytotoxic functions.
Project description:IL-17-producing cells are important mediators of graft-versus-host disease (GVHD) after allogeneic stem cell transplantation (SCT). Here we demonstrate that a distinct CD8+ Tc17 population develops rapidly after SCT but fails to maintain lineage fidelity such that they are unrecognizable in the absence of a fate reporter. Tc17 differentiation is dependent on alloantigen presentation by host-DC together with IL-6. Tc17 cells express high levels of multiple prototypic lineage-defining transcription factors (e.g. RORgt, T-bet) and cytokines (e.g. IL-17A, IL-22, IFNg, GM-CSF, IL-13). Targeted depletion of Tc17 early after transplant protects from lethal acute GVHD, however Tc17 cells are non-cytolytic and fail to mediate graft–versus–leukemia (GVL) effects. Thus, the Tc17 differentiation program during GVHD culminates in a highly plastic, hyper-inflammatory, poorly-cytolytic effector population which we term inflammatory Tc17 (iTc17). Since iTc17 mediate GVHD without contributing to GVL, therapeutic inhibition of iTc17 development in a clinical setting represents an attractive approach for separating GVHD and GVL. Single colour, Illumina MouseRef-8 v2.0 Beadarrays.
Project description:IL-17-producing CD8+ (Tc17)T cells are implicated in the pathogenesis of multiple sclerosis (MS), thereby representing a promising target for therapy. We found that dimethyl fumarate (DMF), a first-line medication for MS upregulated reactive oxygen species (ROS) by glutathione depletion in murine Tc17 cells, which limited IL-17 and diverted Tc17 cells towards cytotoxic T lymphocyte (CTL) signature. DMF enhanced PI3K-AKT-FOXO1-T-bet- as well as STAT5-signaling leading to restricted permissive histone state at the Il17 locus. T-bet-deficiency, inhibiting PI3K-AKT, STAT5 or histone deacetylases prevented DMF-ROS-mediated IL-17 suppression. In MS patients with stable response, DMF suppressed IL-17 production by CD8+ T-cells and triggered diversion from Tc17 towards CTL signature along with enriched ROS-, PI3K-AKT-FOXO1-signaling, demonstrating comparable regulation across species. Accordingly, in the mouse model for MS, DMF limited Tc17-encephalitogenicity. Our findings disclose DMF-ROS-AKT-driven pathway, which selectively modulates Tc17 fate to ameliorate MS, thus opening avenue to develop markers and targets for specific therapy.
Project description:The differentiation of naive CD8+ T cells into effector cells is important for establishing immunity. However, the effect of heterogeneous naive CD8+ T cell populations is not fully understood. Here, we demonstrate that steady-state naive CD8+ T cells are composed of functionally heterogeneous subpopulations that differ in their ability to differentiate into type 17 cytotoxic effector cells (Tc17) in inflammatory disease models. The differential ability of Tc17 differentiation was not related to T-cell receptor (TCR) diversity and antigen specificity but was inversely correlated with self-reactivity acquired during development. Mechanistically, this phenomenon was linked to differential levels of intrinsic TCR sensitivity and basal SMAD3 expression, generating a wide spectrum of Tc17 differentiation potential within naive CD8+ T cell populations. These findings suggest that developmental self-reactivity can determine the fate of naive CD8+ T cells to generate functionally distinct effector populations and achieve immense diversity and complexity in antigen-specific T-cell immune responses.
Project description:IL-17-producing cells are important mediators of graft-versus-host disease (GVHD) after allogeneic stem cell transplantation (SCT). Here we demonstrate that a distinct CD8+ Tc17 population develops rapidly after SCT but fails to maintain lineage fidelity such that they are unrecognizable in the absence of a fate reporter. Tc17 differentiation is dependent on alloantigen presentation by host-DC together with IL-6. Tc17 cells express high levels of multiple prototypic lineage-defining transcription factors (e.g. RORgt, T-bet) and cytokines (e.g. IL-17A, IL-22, IFNg, GM-CSF, IL-13). Targeted depletion of Tc17 early after transplant protects from lethal acute GVHD, however Tc17 cells are non-cytolytic and fail to mediate graft–versus–leukemia (GVL) effects. Thus, the Tc17 differentiation program during GVHD culminates in a highly plastic, hyper-inflammatory, poorly-cytolytic effector population which we term inflammatory Tc17 (iTc17). Since iTc17 mediate GVHD without contributing to GVL, therapeutic inhibition of iTc17 development in a clinical setting represents an attractive approach for separating GVHD and GVL.
Project description:A plethora of data supports a major role of CD4+ and CD8+ T lymphocytes for the initiation, progression and maintenance of allergic contact dermatitis (ACD). However, in-depth understanding of the underlying molecular mechanisms is still limited. NFATc1 , a central component of the Ca++-Calcineurin-NFAT-signalling network, plays an essential role in T cell activation. We therefore investigated its impact on contact hypersensitivity (CHS), the mouse model for ACD. The CHS response to 2,4,6-trinitrochlorobenzene (TNCB) was diminished in Nfatc1fl/flxCd4-cre mice (Nfatc1-/-) as compared to wild-type (WT) animals and associated with a lower percentage of interleukin (IL)17-producing CD8+T (Tc17) cells in both inflamed skin and draining lymph nodes (dLN). In vitro Tc17 polarization assays revealed that Nfatc1-/- CD8+ T cells have a reduced capacity to polarize into Tc17 cells. Applying single-cell RNA sequencing, we realized that NFATc1 controls the T cell differentiation fate. In the absence of NFATc1, CD8+ T cells favour the development of Interferon (IFN)-g-secreting CD8+ T (Tc1) lymphocytes while in its presence they turn into Tc17 cells. Finally, we showed the adoptive transfer of TNCB-sensitized WT CD8+T cells rescued tThe CHS response could be rescued in naïve Nfatc1-/-mice by adoptive transfer of TNCB-sensitized WT CD8+T cells. Our data demonstrate that NFATc1 acts as a molecular switch controllcontrolsing the development of Tc17 cells and can be used as a target to alleviate surveilling CD8+T cell-mediated CHS responses.
Project description:Psoriasis is an inflammatory, IL-17-driven skin disease in which autoantigen-induced CD8+ T cells have been identified as pathogenic drivers. In this study, we used single-cell RNA-seq to identify 11 transcriptionally diverse CD8+ T cell subsets in psoriatic and healthy skin. Among several inflammatory subsets enriched in psoriatic skin, we observed two Tc17 subsets that were metabolically divergent, developmentally related, and expressed CXCL13, which we found to be a biomarker of psoriasis severity. Despite high co-inhibitory receptor expression in the Tc17 clusters, a comparison of these cells with melanoma-infiltrating CD8+ T cells revealed upregulated cytokine, cytolytic, and metabolic transcriptional activity in the psoriatic cells that differed from an exhaustion program. Our findings provide a high-resolution view of cutaneous CD8+ T cells in psoriasis and healthy skin and shed light on their functional distinctions within the chronic pathologies of autoimmunity and cancer.