ABSTRACT: The transcription factor Tcf1 ensures the development and cytotoxic function of NK cells by limiting the expression of Granzymes [Affymetrix]
Project description:The transcription factor Tcf1 ensures the development and cytotoxic function of NK cells by limiting the expression of Granzymes [ChIP-Seq]
Project description:The transcription factor Tcf1 plays an essential role for the development of NK cells, however, its precise role for NK cell development, maturation and function is poorly understood. Here we show that distinct domains of Tcf1 direct bone marrow progenitors towards the NK cell lineage and mediate lineage commitment and NK cell expansion, and that Tcf1 downregulation is required for terminal NK cell maturation. Impaired NK cell development in the absence of Tcf1 is explained by increased cell death due to excessive expression of Granzyme family proteins, which results in NK cell self-destruction. In addition, excessive Granzyme B expression leads to target cell induced NK cell death and consequently reduced target cell killing by NK cells lacking Tcf1. Mechanistically, Tcf1 prevents excessive Granzyme B expression by binding to a newly identified enhancer element upstream of the Granzyme B locus. These data identify an unexpected requirement to limit the expression of cytotoxic effector molecules for lymphocyte development.
Project description:The transcription factor Tcf1 plays an essential role for the development of NK cells, however, its precise role for NK cell development, maturation and function is poorly understood. Here we show that distinct domains of Tcf1 direct bone marrow progenitors towards the NK cell lineage and mediate lineage commitment and NK cell expansion, and that Tcf1 downregulation is required for terminal NK cell maturation. Impaired NK cell development in the absence of Tcf1 is explained by increased cell death due to excessive expression of Granzyme family proteins, which results in NK cell self-destruction. In addition, excessive Granzyme B expression leads to target cell induced NK cell death and consequently reduced target cell killing by NK cells lacking Tcf1. Mechanistically, Tcf1 prevents excessive Granzyme B expression by binding to a newly identified enhancer element upstream of the Granzyme B locus. These data identify an unexpected requirement to limit the expression of cytotoxic effector molecules for lymphocyte development.
Project description:Regulatory T (Treg) cells are important regulators of the immune system and have versatile functions for the homeostasis and repair of tissues. They express the forkhead box transcription factor Foxp3 as a lineage-defining protein. In mature Treg cells, the Foxp3 core promoter is unmethylated indicating that this area could harbor a transcription factor complex to initiate or repress gene expression, respectively. We used an unbiased method to identify Foxp3-promoter-binding transcription factors (TFs) by inverted chromatin immunoprecipitation (IP) followed by quantitative mass spectrometry. We identified several candidate factors which showed Foxp3-promoter suppressive capacity, one of which was T-cell factor 1 (Tcf1). Using viral overexpression and CRISPR/Cas knockout studies, we identified Tcf1 as a repressor of Foxp3 expression in primary conventional CD4 T cells (Tconv). In Tcf1-deficient animals, increased levels of Foxp3intermediateCD25negative T cells were identified in secondary lymphoid tissues, implicating that Tcf1 protects Foxp3-negative T cells from inadvertent Foxp3 expression.
Project description:Hhex encodes a homeobox transcriptional regulator that plays a key role in embryonic development and hematopoiesis. Hhex is highly expressed in NK cells and germline deletion of Hhex results in significant defects in lymphoid development, including NK cells. However, whether Hhex is intrinsically required throughout NK cell development or for NK cell function remains unknown. To investigate this, we generated mice that specifically lack Hhex in NK cells. Hhex was intrinsically required for NK cell homeostasis, while NK cell differentiation, IL-15 responsiveness and cytotoxic function were largely normal in the absence of Hhex. Unexpectedly, increased IL-15 availability failed to rescue Hhex-deficient NK cell homeostasis, suggesting that Hhex regulates developmental pathways extrinsic to those dependent on IL-15. Gene expression and functional genetic approaches revealed that Hhex promoted NK cell survival by repressing BIM expression, a key apoptotic mediator in NK cells. This study identifies Hhex as a novel transcription factor essential for NK cell biology.
Project description:The HMG-box factor Tcf1 is required during T-cell development in the thymus and mediates the nuclear response to Wnt signals. Tcf1-/- mice have previously been characterized and show developmental blocks at the CD4-CD8- double negative (DN) to CD4+CD8+ double positive transition. Due to the blocks in T-cell development, Tcf1-/- mice normally have a very small thymus. Unexpectedly, a large proportion of Tcf1-/- mice spontaneously develop thymic lymphomas with 50% of mice developing a thymic lymphoma/leukemia at the age of 16 wk. These lymphomas are clonal, highly metastatic, and paradoxically show high Wnt signaling when crossed with Wnt reporter mice and have high expression of Wnt target genes Lef1 and Axin2. In wild-type thymocytes, Tcf1 is higher expressed than Lef1, with a predominance of Wnt inhibitory isoforms. Loss of Tcf1 as repressor of Lef1 leads to high Wnt activity and is the initiating event in lymphoma development, which is exacerbated by activating Notch1 mutations. Thus, Notch1 and loss of Tcf1 functionally act as collaborating oncogenic events. Tcf1 deficiency predisposes to the development of thymic lymphomas by ectopic up-regulation of Lef1 due to lack of Tcf1 repressive isoforms and frequently by cooperating activating mutations in Notch1. Tcf1 therefore functions as a T-cell‚Äìspecific tumor suppressor gene, besides its established role as a Wnt responsive transcription factor. Thus, Tcf1 acts as a molecular switch between proliferative and repressive signals during T-lymphocyte development in the thymus. Using the Tcf1-/- DeltaVII/DeltaVII knockout mouse (Verbeek et al. Nature 1995), thymocytes of 17 mice (5 control Tcf+/-, 4 Tcf-/- and 8 Tcf-/- with thymic lymphoma) were homogenized for RNA isolation using Qiagen RNeasy minicolumns. The quantity and quality of total RNA was determined using spectrophotometry (Nanodrop) and an Agilent Bioanalyzer. One ¬µg of RNA was used to generate cRNA using Affymetrix One cycle cDNA synthesis kit (Affymetrix, Santa Clara, CA, USA), after which the samples were biotinylated using an Affymetrix IVT labeling kit (Affymetrix). The samples were hybridized overnight at 42¬?C to GeneChip mouse genome 430 2.0 Arrays (Affymetrix). Washing and staining steps were performed on a Fluidics station 450, and the Genechips were scanned using a GeneChip scanner 3000 (Affymetrix) at the Department of Immunology, Erasmus Medical Center. Raw data were normalized and summarized using Robust Multichip Average (RMA) method. The experiment consists of 5 control Tcf+/- thymi, 4 Tcf-/- thymi and 8 Tcf-/- thymus samples with thymic lymphoma.
Project description:The HMG-box factor Tcf1 is required during T-cell development in the thymus and mediates the nuclear response to Wnt signals. Tcf1−/− mice have previously been characterized and show developmental blocks at the CD4−CD8− double negative (DN) to CD4+CD8+ double positive transition. Due to the blocks in T-cell development, Tcf1−/− mice normally have a very small thymus. Unexpectedly, a large proportion of Tcf1−/− mice spontaneously develop thymic lymphomas with 50% of mice developing a thymic lymphoma/leukemia at the age of 16 wk. These lymphomas are clonal, highly metastatic, and paradoxically show high Wnt signaling when crossed with Wnt reporter mice and have high expression of Wnt target genes Lef1 and Axin2. In wild-type thymocytes, Tcf1 is higher expressed than Lef1, with a predominance of Wnt inhibitory isoforms. Loss of Tcf1 as repressor of Lef1 leads to high Wnt activity and is the initiating event in lymphoma development, which is exacerbated by activating Notch1 mutations. Thus, Notch1 and loss of Tcf1 functionally act as collaborating oncogenic events. Tcf1 deficiency predisposes to the development of thymic lymphomas by ectopic up-regulation of Lef1 due to lack of Tcf1 repressive isoforms and frequently by cooperating activating mutations in Notch1. Tcf1 therefore functions as a T-cell–specific tumor suppressor gene, besides its established role as a Wnt responsive transcription factor. Thus, Tcf1 acts as a molecular switch between proliferative and repressive signals during T-lymphocyte development in the thymus. Using the Tcf1−/− ΔVII/ΔVII knockout mouse (Verbeek et al. Nature 1995), thymocytes of 17 mice (5 control Tcf+/-, 4 Tcf-/- and 8 Tcf-/- with thymic lymphoma) were homogenized for RNA isolation using Qiagen RNeasy minicolumns. The quantity and quality of total RNA was determined using spectrophotometry (Nanodrop) and an Agilent Bioanalyzer. One µg of RNA was used to generate cRNA using Affymetrix One cycle cDNA synthesis kit (Affymetrix, Santa Clara, CA, USA), after which the samples were biotinylated using an Affymetrix IVT labeling kit (Affymetrix). The samples were hybridized overnight at 42°C to GeneChip mouse genome 430 2.0 Arrays (Affymetrix). Washing and staining steps were performed on a Fluidics station 450, and the Genechips were scanned using a GeneChip scanner 3000 (Affymetrix) at the Department of Immunology, Erasmus Medical Center. Raw data were normalized and summarized using Robust Multichip Average (RMA) method.
2014-02-14 | GSE54976 | GEO
Project description:Transcription factor Zhx2 restricts NK cell antitumor immunity by limiting maturation and survival
Project description:Natural killer (NK) cells are innate lymphoid cells that play a critical role in the direct immune defense against tumor cells and pathogens, and additionally have important immune regulatory functions by cytokine secretion. Whereas NK cell biology has been extensively studied in mouse models, transcriptional control of human NK cell differentiation is poorly understood. In this study, we generated ETS1-deficient human embryonic stem cell (hESC) clones using the CRISPR/Cas9 technology. In a complementary approach, we generated ETS1 loss-of-function cord blood hematopoietic stem cells (HSCs) by retroviral transduction of the dominant-negative ETS1 p27 isoform. We show that the transcription factor ETS1 is required for human NK cell differentiation. Transcriptome and ChIP analysis reveal that ETS1 directly regulates expression of several NK cell-linked transcription factors. Also, expression of genes involved in cytokine secretion and cytotoxic activity is ETS1-dependent, whereby these effector functions are decreased in residual NK cells developing from ETS1 loss-of-function cord blood hematopoietic stem cells. Our data show that ETS1 is a critical regulator of human NK cell development and function, and provide important insights in the underlying molecular mechanisms.