Project description:Regulatory T cells (Tregs) are crucial for the maintenance of immune tolerance and restrict immunopathology during inflammation, yet they limit efficient anti-tumor immunity in the tumor microenvironment (TME). Effector Tregs (eTregs) are thought to be the cellular subset equipped with the strongest immunosuppressive and cancer promoting properties. Here we found by in preclinical cancer models, that Treg specific deletion of IL23R reduces tumor growth. Using heterozygous conditional knock-out mice in which Il23r KO and Il23r WT Tregs coexist in the same tumor microenvironment, we found that IL-23 sensing represents a crucial signal driving the maintenance and stabilization of eTregs involving the transcription factor Foxp3.
Project description:Through their functional diversification, CD4+ T cells play key roles in both driving and constraining immune-mediated pathology. Transcription factors are critical in the generation and maintenance of cellular diversity and negative regulators antagonistic to alternate fates often act in conjunction with positive regulators to stabilize lineage specification1. Polymorphisms within the locus encoding a transcription factor BACH2 are associated with diverse immune-mediated diseases including asthma2, multiple sclerosis3, Crohn¹s disease4-5, coeliac disease6, vitiligo7 and type 1 diabetes8. A role for Bach2 in maintaining immune homeostasis, however, has not been established. Here, we define Bach2 as a broad regulator of immune activation that stabilizes immunoregulatory capacity while repressing the differentiation programmes of multiple effector lineages in CD4+ T cells. Bach2 was required for efficient formation of regulatory (Treg) cells and consequently for suppression of lethal inflammation in a manner that was Treg cell dependent. Assessment of the genome-wide function of Bach2, however, revealed that it represses genes associated with effector cell differentiation. Consequently, its absence during Treg polarization resulted in inappropriate diversion to effector lineages. In addition, Bach2 constrained full effector differentiation within Th1, Th2 and Th17 cell lineages. These findings identify Bach2 as a key regulator of CD4+ T-cell differentiation that prevents inflammatory disease by controlling the balance between tolerance and immunity. The role of Bach2t to regulate immune homeostasis was investigated by mapping DNA binding profiles of Bach2 in iTreg condition. The function of Bach2 was also evaluated by comparing transcriptome in WT and Bach2-deficient iTreg cells and further comparison was done with transcriptome in naive, Th1, Th2, and Th17 conditions.
Project description:Interleukin-23 (IL-23) is a proinflammatory cytokine mainly produced by myeloid cells that promotes tumor growth in various preclinical cancer models and correlates with adverse outcomes. However, as to how IL-23 fuels tumor growth is unclear. Here, we found tumor-associated macrophages to be the main source of IL-23 in mouse and human tumor microenvironments. Among IL-23-sensing cells, we identified a subset of tumor-infiltrating regulatory T (Treg) cells that display a highly suppressive phenotype across mouse and human tumors. The use of three preclinical models of solid cancer in combination with genetic ablation of Il23r in Treg cells revealed that they are responsible for the tumor-promoting effect of IL-23. Mechanistically, we found that IL-23 sensing represents a crucial signal driving the maintenance and stabilization of effector Treg cells involving the transcription factor Foxp3. Our data support that targeting the IL-23/IL-23R axis in cancer may represent a means of eliciting antitumor immunity.
Project description:Regulatory T (Treg) cells can facilitate transplant tolerance and attenuate autoimmune- and inflammatory diseases. Therefore, it is clinically relevant to stimulate Treg cell expansion and function in vivo and to create therapeutic Treg cell products in vitro. We report that TNF receptor 2 (TNFR2) is a unique costimulus for naïve, thymus-derived (t)Treg cells from human blood that promotes their differentiation into non-lymphoid tissue (NLT)-resident effector Treg cells, without Th-like polarization. In contrast, CD28 costimulation maintains a lymphoid tissue (LT)-resident Treg cell phenotype. We base this conclusion on transcriptome and proteome analysis of TNFR2- and CD28-costimulated CD4+ Treg cells and conventional T (Tconv) cells, followed by bioinformatic comparison with published transcriptomic Treg cell signatures from NLT and LT in health and disease, including autoimmunity and cancer. These analyses illuminate that TNFR2 costimulation promotes Treg cell capacity for survival, migration, immunosuppression and tissue regeneration. Functional studies confirmed improved migratory ability of TNFR2-costimulated tTreg cells. Flow cytometry validated the presence of the TNFR2-driven Treg cell signature in effector/memory Treg cells from the human placenta as opposed to blood. Thus, TNFR2 can be exploited as driver of NLT-resident Treg cell differentiation for adoptive cell therapy or antibody-based immunomodulation in human disease.
Project description:Through their functional diversification, CD4+ T cells play key roles in both driving and constraining immune-mediated pathology. Transcription factors are critical in the generation and maintenance of cellular diversity and negative regulators antagonistic to alternate fates often act in conjunction with positive regulators to stabilize lineage specification1. Polymorphisms within the locus encoding a transcription factor BACH2 are associated with diverse immune-mediated diseases including asthma2, multiple sclerosis3, Crohn¹s disease4-5, coeliac disease6, vitiligo7 and type 1 diabetes8. A role for Bach2 in maintaining immune homeostasis, however, has not been established. Here, we define Bach2 as a broad regulator of immune activation that stabilizes immunoregulatory capacity while repressing the differentiation programmes of multiple effector lineages in CD4+ T cells. Bach2 was required for efficient formation of regulatory (Treg) cells and consequently for suppression of lethal inflammation in a manner that was Treg cell dependent. Assessment of the genome-wide function of Bach2, however, revealed that it represses genes associated with effector cell differentiation. Consequently, its absence during Treg polarization resulted in inappropriate diversion to effector lineages. In addition, Bach2 constrained full effector differentiation within Th1, Th2 and Th17 cell lineages. These findings identify Bach2 as a key regulator of CD4+ T-cell differentiation that prevents inflammatory disease by controlling the balance between tolerance and immunity.
Project description:We show that Ly49+CD122+ CD8+ Treg have a distinct expression profie compared to conventional Foxp3+ CD4+ Treg and CD49 lo CD122+ CD8 effector like cells. RNA was extracted from sorted cells and sent for sequencing
Project description:Atherosclerosis, a pathological condition underlying cardiovascular diseases, involves chronic inflammation with a strong autoimmune component. Detailed molecular definition of autoreactive CD4+T cells in atherosclerotic patients is critical for understanding their role in disease pathogenesis. Apolipoprotein B (APOB) is a clinically relevant atherosclerosis-related autoantigen. Here, we used an activation-induced marker assay to conduct deep transcriptomic analyses of circulating APOB-reactive CD4+T cells from 40 patients with coronary artery disease. We identified autoreactive T cells expressing tissue-homing chemokine receptors and effector Treg signatures, suggesting recirculation of APOB-specific CD4+T cells between blood and atherosclerotic plaques. Treg gene signature and oligoclonality peaked in patients with mild disease, but declined in those with severe atherosclerosis. By contrast, clonal expansion and expression of effector molecules in inflammatory APOB-specific CD4+T cells increased with progressing disease severity. Thus, the autoimmune response in atherosclerosis starts with an atheroprotective regulatory program but switches to an inflammatory phenotype, likely accelerating disease progression.
Project description:Coordinated repression of gene expression by evolutionarily conserved microRNA (miRNA) clusters and paralogs ensures that miRNAs efficiently exert their biological impact. Combining both loss- and gain-of-function genetic approaches, here we show that the miR-23~27~24 clusters regulate multiple aspects of T cell biology, particularly Th2 immunity. Low expression of this miRNA family confers proper effector T cell function at both physiological and pathological settings. Further studies in T cells with exaggerated regulation by individual members of the miR-23~27~24 clusters revealed miR-24 and miR-27 collaboratively limit Th2 responses through targeting IL-4 and GATA3 in both direct and indirect manners. Intriguingly, while overexpression of the entire miR-23 cluster also negatively impacts other Th lineages, enforced expression of miR-24, in contrast to miR-23 and miR-27, actually promotes the differentiation of Th1, Th17 and iTreg cells, implying that under certain conditions, miRNA families can fine tune the biological effects of their regulation by having individual members antagonize rather than cooperate with each other. Together, our results identify a miRNA family with important immunological roles and suggest tight regulation of miR-23~27~24 clusters in T cells is required to maintain optimal effector function and to prevent aberrant immune responses. naïve T cells isolated from mice with T cell-specific overexpression of the entire miR-23 cluster or individual miR-23 family members as well as from mice with T cell-specific deletion of both miR-23a/b clusters
Project description:Human FOXP3+ regulatory T (Treg) cells are central to immune tolerance. However, their heterogeneity and differentiation remain incompletely understood. Here we use single-cell RNA and T cell receptor sequencing to resolve Treg cells from healthy individuals and patients with or without acute graft-versus-host disease (aGVHD) who undergo stem cell transplantation. These analyses, combined with functional assays, separate Treg cells into naïve/activated/effector stages, and resolve the HLA-DRhi, LIMS1hi, highly suppressive FOXP3hi, and highly proliferative MKI67hi effector subsets. Trajectory analysis assembles Treg subsets into two differentiation paths (I/II) with distinctive phenotypic/functional programs, ending with the FOXP3hi and MKI67hi subsets, respectively. Transcription factors FOXP3 and SUB1 contribute to some Path I and Path II phenotypes, respectively. These FOXP3hi and MKI67hi subsets and two differentiation pathways are conserved in transplanted patients, despite having functional/migratory impairments under aGVHD. The findings expand the understanding of Treg cell heterogeneity and differentiation and provide a single-cell atlas for the dissection of Treg complexity in health and disease.