Project description:Post-translational modifications of histones are well-established epigenetic modifications that play an important role in gene expression and regulation. These modifications are partly mediated by the Trithorax group (TrxG) complex, which regulates the induction or maintence of gene transcription. We investigated the role of Menin, a component of the TrxG complex, in the acquisition and maintenance of T helper type 2 (Th2) cell identity using T cell-specific Menin-deficient mice. Our gene expression analysis revealed that Menin was involved in the maintenance of the high level expression of the previously identified Th2-specific genes rather than the induction of these genes. This result suggests a role of Menin in the maintenance of Th2 cell identity. Menin directly bound to the Gata3 gene locus, and this Menin-Gata3 axis appeared to form a core unit of the Th2-specific gene regulatory network. Consistent with the phenotype of Menin-deficient Th2 cells observed in vitro, Menin deficiency resulted in the attenuation of effector Th2 cell-induced airway inflammation. In addition, in memory Th2 cells, Menin was found to play an important role in the maintenance of the expression of Th2-specific genes, including Gata3, Il4, and Il13. Consequently, Menin-deficient memory Th2 cells showed an impaired abiliy to recruit eosinophils to the lung, resulting in the attenuation of memory Th2 cell-induced airway inflammation. This study confirmed the critical role of Menin in Th2 cell-mediated immune responses.
Project description:Post-translational modifications of histones are well-established epigenetic modifications that play an important role in gene expression and regulation. These modifications are partly mediated by the Trithorax group (TrxG) complex, which regulates the induction or maintence of gene transcription. We investigated the role of Menin, a component of the TrxG complex, in the acquisition and maintenance of T helper type 2 (Th2) cell identity using T cell-specific Menin-deficient mice. Our gene expression analysis revealed that Menin was involved in the maintenance of the high level expression of the previously identified Th2-specific genes rather than the induction of these genes. This result suggests a role of Menin in the maintenance of Th2 cell identity. Menin directly bound to the Gata3 gene locus, and this Menin-Gata3 axis appeared to form a core unit of the Th2-specific gene regulatory network. Consistent with the phenotype of Menin-deficient Th2 cells observed in vitro, Menin deficiency resulted in the attenuation of effector Th2 cell-induced airway inflammation. In addition, in memory Th2 cells, Menin was found to play an important role in the maintenance of the expression of Th2-specific genes, including Gata3, Il4, and Il13. Consequently, Menin-deficient memory Th2 cells showed an impaired abiliy to recruit eosinophils to the lung, resulting in the attenuation of memory Th2 cell-induced airway inflammation. This study confirmed the critical role of Menin in Th2 cell-mediated immune responses.
Project description:Lysosome-mediated autophagy (including mitophagy) is crucial for cell survival and homeostasis. Although the mechanisms of lysosome activation during stress are well recognized, the epigenetic regulation of lysosomal gene expression remains largely unexplored. Menin, encoded by the MEN1 gene, is a chromatin-related protein that is widely involved in gene transcription via histone modifications. Here, we report that menin regulates the transcription of important lysosomal genes through MLL-mediated H3K4me3 reprogramming, which is necessary for maintaining lysosomal homeostasis. Menin also directly controls the expression of SQSTM1 and MAP1LC3B to maintain autophagic flux in an AMPK/mTORC1-independent manner. Moreover, menin maintains mitochondrial genome integrity and homeostasis by tightly regulating TFAM expression. In genetically engineered mouse models, Men1 deficiency resulted in severe lysosomal/mitochondrial dysfunction and an impaired self-clearance ability, which further led to metabolite accumulation and spontaneous lung cancer development. SP2509, a histone demethylase inhibitor, effectively reversed the downregulation of lysosomal/mitochondrial genes caused by loss of Men1. Our study confirms the previously unrecognized biological and mechanistic importance of menin-mediated H3K4me3 in maintaining organelle homeostasis.
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
Project description:Functionally polarized CD4+ T helper (Th) cells such as Th1, Th2 and Th17 cells are central to the regulation of acquired immunity. However, the molecular mechanisms governing the maintenance of the polarized functions of Th cells remain unclear. GATA3, a master regulator of Th2 cell differentiation, initiates the expressions of Th2 cytokine genes and other Th2-specific genes. GATA3 also plays important roles in maintaining Th2 cell function and in continuous chromatin remodeling of Th2 cytokine gene loci. However, it is unclear whether continuous expression of GATA3 is required to maintain the expression of various other Th2-specific genes. In this report, genome-wide DNA gene expression profiling revealed that GATA3 expression is critical for the expression of a certain set of Th2-specific genes. We demonstrated that GATA3 dependency is reduced for some Th2-specific genes in fully developed Th2 cells compared to that observed in effector Th2 cells, whereas it is unchanged for other genes. Moreover, effects of a loss of GATA3 expression in Th2 cells on the expression of cytokine and cytokine receptor genes were examined in detail. A critical role of GATA3 in the regulation of Th2-specific gene expression is confirmed in in vivo generated antigen-specific memory Th2 cells. Therefore, GATA3 is required for the continuous expression of the majority of Th2-specific genes involved in maintaining the Th2 cell identity. Mock-transfected and GATA3 siRNA-transfected Th2 and Th2-4th cells are profiled for mRNA expression
Project description:Lysosome-mediated autophagy (including mitophagy) is crucial for cell survival and homeostasis. Although the mechanisms of lysosome activation during stress are well recognized, the epigenetic regulation of lysosomal gene expression remains largely unexplored. Menin, encoded by the MEN1 gene, is a chromatin-related protein that is widely involved in gene transcription via histone modifications. Here, we report that menin regulates the transcription of specific lysosomal genes, such as CTSB, CTSE, and TFE3, through MLL-mediated H3K4me3 reprogramming, which is necessary for maintaining lysosomal homeostasis. Menin also directly controls the expression of SQSTM1 and MAP1LC3B to maintain autophagic flux in an AMPK-mTORC1-independent manner. Furthermore, loss of menin led to mitochondrial dysfunction, resulting in elevated levels of reactive oxygen species (ROS) and ultimately leading to genome instability. In genetically engineered mouse models, Men1 deficiency resulted in severe lysosomal and mitochondrial dysfunction and an impaired self-clearance ability, which further led to metabolite accumulation and spontaneous lung cancer development. SP2509, a histone demethylase inhibitor, effectively reversed the downregulation of lysosomal and mitochondrial genes caused by loss of Men1. Our study confirms the previously unrecognized biological and mechanistic importance of menin-mediated H3K4me3 in maintaining organelle homeostasis.
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.
Project description:Functionally polarized CD4+ T helper (Th) cells such as Th1, Th2 and Th17 cells are central to the regulation of acquired immunity. However, the molecular mechanisms governing the maintenance of the polarized functions of Th cells remain unclear. GATA3, a master regulator of Th2 cell differentiation, initiates the expressions of Th2 cytokine genes and other Th2-specific genes. GATA3 also plays important roles in maintaining Th2 cell function and in continuous chromatin remodeling of Th2 cytokine gene loci. However, it is unclear whether continuous expression of GATA3 is required to maintain the expression of various other Th2-specific genes. In this report, genome-wide DNA gene expression profiling revealed that GATA3 expression is critical for the expression of a certain set of Th2-specific genes. We demonstrated that GATA3 dependency is reduced for some Th2-specific genes in fully developed Th2 cells compared to that observed in effector Th2 cells, whereas it is unchanged for other genes. Moreover, effects of a loss of GATA3 expression in Th2 cells on the expression of cytokine and cytokine receptor genes were examined in detail. A critical role of GATA3 in the regulation of Th2-specific gene expression is confirmed in in vivo generated antigen-specific memory Th2 cells. Therefore, GATA3 is required for the continuous expression of the majority of Th2-specific genes involved in maintaining the Th2 cell identity.