Project description:It is becoming clear that the acquisition of T cell functions is closely linked to the reprogramming of the metabolic pathway. However, the impact of metabolic changes on the differentiation of helper T cell subsets remains unclear. We herein demonstrate a critical role of glutamine metabolism in regulating type 2-immune response. Bach2, a transcriptional repressor, binds to an AP-1 motif, and suppresses Th2 cell differentiation and glutaminolysis. Glutaminase 2, which controls glutamine metabolism, was identified as a Bach2 target gene. The pharmacological inhibition of glutamine metabolism normalized allergic lung inflammation that developed spontaneously in T-cell specific Bach2-deficient mice. These findings reveal the importance of the Bach2-dependent modulation of glutamine metabolism in regulating Th2 cell differentiation and Th2 cell- mediated inflammation.
Project description:It is becoming clear that the acquisition of T cell functions is closely linked to the reprogramming of the metabolic pathway. However, the impact of metabolic changes on the differentiation of helper T cell subsets remains unclear. We herein demonstrate a critical role of glutamine metabolism in regulating type 2-immune response. Bach2, a transcriptional repressor, binds to an AP-1 motif, and suppresses Th2 cell differentiation and glutaminolysis. Glutaminase 2, which controls glutamine metabolism, was identified as a Bach2 target gene. The pharmacological inhibition of glutamine metabolism normalized allergic lung inflammation that developed spontaneously in T-cell specific Bach2-deficient mice. These findings reveal the importance of the Bach2-dependent modulation of glutamine metabolism in regulating Th2 cell differentiation and Th2 cell- mediated inflammation.
Project description:Although Bach2 plays an important role in regulating the Th2-type immune response, the underlying molecular mechanisms remain unclear. We herein demonstrate that Bach2 associates with Batf and binds to the regulatory regions of the Th2 cytokine gene loci. The Bach2-Batf complex antagonizes the recruitment of the Batf-Irf4 complex to AP-1 motifs and suppresses Th2 cytokine production. Furthermore, we found that Bach2 regulates the Batf and Batf3 expressions via two distinct pathways. First, Bach2 suppresses the maintenance of the Batf and Batf3 expression through the inhibition of IL-4 production. Second, the Bach2-Batf complex directly binds to the Batf and Batf3 gene loci and reduces transcription by interfering with the Batf-Irf4 complex. These findings suggest that IL-4 and Batf form a positive feedback amplification loop to induce Th2 cell differentiation and the subsequent Th2-type immune response, and Bach2-Batf interactions are required to prevent an excessive Th2 response.
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:Bach2 codes for a transcriptional regulator exerting major influences on T cell mediated immune regulation. Effector CTLs derived from in vitro activation of murine CD8+ T cells showed increased proliferative and cytolytic capacity in the absence of BACH2. Before activation, BACH2-deficient CD8+ T cells had a higher abundance of memory and reduced abundance of naïve cells compared to wild-type. CTLs derived from central memory T cells were more potently cytotoxic than those derived from naïve T cells, but even within separated subsets, BACH2-deficiency conferred a cytotoxic advantage. Immunofluorescence and electron microscopy revealed larger granules in BACH2-deficient compared to wild-type CTLs, and proteomic analysis showed an increase in granule content, including perforin and granzymes. Thus, the enhanced cytotoxicity observed in effector CTLs lacking BACH2 arises not only from differences in their initial differentiation state but also inherent production of enlarged cytolytic granules. These results demonstrate how a single gene deletion can produce a CTL super-killer.
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:The role of FoxP3+ regulatory T (Treg) cells in the maintenance of immunological tolerance is well established. Recently, genome-wide association studies (GWAS) in humans have associated polymorphisms within the BACH2 locus encoding the transcription factor BTB and CNC homology 1, basic leucine zipper transcription factor 2 (Bach2) with diverse allergic and autoimmune diseases including asthma, multiple sclerosis, Crohn's disease, celiac disease, generalized vitiligo and type 1 diabetes. Common to these diseases is a failure to adequately maintain immunological tolerance. However, a role for Bach2 in this process has not been established. Here, by assessing the phenotype of mice in which the Bach2 gene is disrupted, we demonstrate a non-redundant role for Bach2 in the prevention of a spontaneous lethal inflammatory disorder predominantly affecting the lung and gut with excessive T helper 2 (Th2) responses and formation of circulating autoantibodies. Bach2 was necessary for efficient induction of FoxP3 expression both during thymopoesis and upon stimulation of naïve peripheral CD4+ T cells under Treg polarizing conditions in vitro. Consequently, in bone marrow reconstitution experiments, Bach2 expression within the haematopoetic system was necessary for suppression of lethal autoimmunity in a manner that was FoxP3 dependent. These findings demonstrate a requirement for Bach2 in early lineage commitment of both thymic and induced Treg cells and point to shared mechanisms that underlie diverse allergic and autoimmune disorders that may serve as targets in the development of novel therapeutic strategies. Six samples were collected from separate mice: three Ly5.1+ wildtype thymocyte samples (biological replicates) and three Ly5.1- Bach2 knockout thymocyte samples (biological replicates).
Project description:Although CD4 T cell senescence plays an important role in immunosenescence, the mechanisms remain unclear. We found that T cell-specific Menin deficiency results in the premature senescence of CD4 T cells, accompanied by the senescence-associated secretory phenotype (SASP) after antigenic stimulation. TH1 and TH2 differentiation was dysregulated in Menin-knockout CD4 T cells. Bach2, which regulates SASP and TH differentiation, was identified as a Menin target. Menin binds to the Bach2 locus, and controls its expression through maintenance of histone acetylation. These findings reveal a critical role of the Menin-Bach2 pathway in regulating CD4 T cell senescence and homeostasis, thus indicating the involvement of this pathway in the inhibition of age-associated development of inflammatory diseases, which are induced by immunosenescence. Examination of transcriptional factor Menin binding and histone modefications in Menin WT and KO CD4 T cells