Project description:Mature lymphoid cells express the transcriptional repressor Bach2, which imposes regulation on humoral and cellular immunity. Here we found critical roles for Bach2 in the development of cells of the B lineage, commencing from the common lymphoid progenitor (CLP) stage, with Bach1 as an auxiliary. Overexpression of Bach2 in pre-pro-B cells deficient in the transcription factor EBF1 and single-cell analysis of CLPs revealed that Bach2 and Bach1 repressed the expression of genes important for myeloid cells (M-bM-^@M-^Xmyeloid genesM-bM-^@M-^Y). Bach2 and Bach1 bound to presumptive regulatory regions of the myeloid genes. Bach2hi CLPs showed resistance to myeloid differentiation even when cultured under myeloid conditions. Our results suggest that Bach2 functions with Bach1 and EBF1 to promote B cell development by repressing myeloid genes in CLPs. WT and Bach1 and Bach2 double deficient (DD) CLPs. Multipotent progenitors (MPPs) infected with control-GFP and Bach2-GFP and cultured several condition. Follicular B cells (Fo B) stimulated with IgM. Three expreriments was performed in this paper.
Project description:Mature lymphoid cells express the transcriptional repressor Bach2, which imposes regulation on humoral and cellular immunity. Here we found critical roles for Bach2 in the development of cells of the B lineage, commencing from the common lymphoid progenitor (CLP) stage, with Bach1 as an auxiliary. Overexpression of Bach2 in pre-pro-B cells deficient in the transcription factor EBF1 and single-cell analysis of CLPs revealed that Bach2 and Bach1 repressed the expression of genes important for myeloid cells (‘myeloid genes’). Bach2 and Bach1 bound to presumptive regulatory regions of the myeloid genes. Bach2hi CLPs showed resistance to myeloid differentiation even when cultured under myeloid conditions. Our results suggest that Bach2 functions with Bach1 and EBF1 to promote B cell development by repressing myeloid genes in CLPs.
Project description:Background: Pulmonary alveolar proteinosis (PAP) is a rare disease showing excess accumulation of surfactant protein in the alveolar spaces. It chiefly results from a dysfunction of alveolar macrophages (AMs) due to a lack of granulocyte macrophage colony-stimulating factor (GM-CSF) signaling including the expression of PU.1. We previously reported that mice deficient for Bach2 developed PAP-like disease due to a defect of lipid handling by AMs. Recently, Bach1 and Bach2 have been reported to function redundantly in early B cell development. The aim of this study was to investigate the function of Bach1 and Bach2 in alveolar macrophage and lung homeostasis. Methods: We generated mice lacking both Bach1 and Bach2 (Bach1/2 DKO mice) and investigated their body weight and survival rate. Whole lungs of mice were observed with Hematoxylin and eosin (HE) stain when they were 8 or 12-13 weeks old. The expression of surface markers and the numbers of alveolar macrophages and eosinophils in BAL were analyzed by flow cytometry (FACS). We also analyzed tissue macrophages in bone marrow and spleen by FACS. We administered N-acetyl cysteine to mice from prenatal stage and observed lung pathology at 12 weeks. Result: Bach1/2 DKO mice showed a more rapid and severe PAP phenotype than Bach2-deficient mice (Bach2 KO mice), whereas Bach1-deficient mice (Bach1 KO mice) did not develop any pulmonary disease. AMs in Bach1/2 DKO mice showed a foamy appearance, suggesting a defect in lipid handling. In contrast, the numbers of bone marrow macrophages and red pulp macrophages were not affected in Bach1/2 DKO mice. The PAP-like disease in Bach1/2 DKO and Bach2 KO mice was not ameliorated by N-acetyl cysteine. Conclusion: We suggest that Bach1 and Bach2 work in a complementary manner for the normal function of AMs and the maintenance of surfactant homeostasis in the lungs. Oxidative stress may be involved in the process of PAP by inactivating Bach1 and Bach2.
Project description:Transcription factor Bach2 has been reported to regulate the development and function of multiple immune cells including T cells and B cells. As a transcription repressor, Bach2 plays its role by repressing the expression of downstream targets. We are interested in whether Bach2 will affect NK cell development and what's the relationship between Bach2 and other transcription factors in regulating NK cell function. Here we try to explore the chromatin accessibility of Bach2 by ATAC-seq. We compared enriched peaks in mouse NK cell from Bach2 conditional knockout mice and control mice.
Project description:We report here the broad transcriptomic program regulated by BACH2 transcription factor. We used a well suited in vitro model of B cell differentiation to evaluate transcriptomic program governed by BACH2 leading to Plasmocyte (PC) differentiation. In this model B cells were cultured with anti-BCR, CpG, CD40L and Interleukin-2 (IL2). This Interleukin triggers PC differentiation by directly repressing BACH2 expression. We artificially inhibit BACH2 expression by siRNA and found that this condition is sufficient to trigger PC differentiation without IL2. To understand global changes induced by enforced BACH2 downregulation we compared Chip-Sequencing data between activated B Cells and BACH2 deficient B cells (siBACH2). We found that BACH2 binds more than 3000 genes across the human genome. RNAsequencing comparing IL2 drivent committed cells and siBACH2 committed cells highlighs a large common trasncriptional program shared by both conditions and involved in B cell destiny. This study provides evidence that BACH2 is a guardian of B cell fate.
Project description:BTB and CNC homology 1 (BACH1) is a heme-binding transcription factor repressing the transcription from a subset of MAF recognition elements (MAREs) at low intracellular heme levels. Upon heme binding, BACH1 is released from the MAREs, resulting in increased expression of antioxidant response genes. To systematically address the gene regulatory networks involving BACH1, we combined chromatin immunoprecipitation-sequencing (ChIP-seq) analysis of BACH1 target genes in HEK 293 cells with knock-down of BACH1 using three independent types of small interfering RNAs followed by transcriptome profiling using microarrays. The 59 BACH1 target genes identified by ChIP-seq were found highly enriched in genes showing expression changes after BACH1 knock-down, demonstrating the impact of BACH1 repression on transcription. In addition to known and new BACH1 targets involved in heme degradation (HMOX1, FTL, FTH1, ME1, SLC48A1) and redox regulation (GCLC, GCLM, SLC7A11), we also discovered BACH1 target genes effecting cell cycle and apoptosis pathways (ITPR2, CALM1, SQSTM1, TFE3, EWSR1, CDK6, BCL2L11, MAFG) as well as subcellular transport processes (CLSTN1, PSAP, MAPT, vault RNA). The newly identified impact of BACH1 on genes involved in neurodegenerative processes and proliferation provides an interesting basis for future dissection of BACH1-mediated gene repression in neurodegeneration and virus-induced cancerogenesis. Examination of BACH1 binding in HEK 293T cells by chromatin immunoprecipitation-sequencing (CHIP-seq) with input DNA as control.
Project description:BTB and CNC homology 1 (BACH1) is a heme-binding transcription factor repressing the transcription from a subset of MAF recognition elements (MAREs) at low intracellular heme levels. Upon heme binding, BACH1 is released from the MAREs, resulting in increased expression of antioxidant response genes. To systematically address the gene regulatory networks involving BACH1, we performed knock-down of BACH1 in HEK 293T cells using three independent types of small interfering RNAs followed by transcriptome profiling using microarrays.
Project description:The transcription factor Bach2 is a critical negative regulator of Tfh cell differentiation, especially IL-4 subset. Tfh cells from the mesenteric lymph nodes of WT and Bach2 CD4 conditional KO mice were collected to process the Rna-seq. Mechanistically, Bach2 may limit abnormal IL-4-produicng Tfh cell formation by repressing c-Maf, CXCR5 and IL-4.
Project description:BTB and CNC homology 1 (BACH1) is a heme-binding transcription factor repressing the transcription from a subset of MAF recognition elements (MAREs) at low intracellular heme levels. Upon heme binding, BACH1 is released from the MAREs, resulting in increased expression of antioxidant response genes. To systematically address the gene regulatory networks involving BACH1, we combined chromatin immunoprecipitation-sequencing (ChIP-seq) analysis of BACH1 target genes in HEK 293 cells with knock-down of BACH1 using three independent types of small interfering RNAs followed by transcriptome profiling using microarrays. The 59 BACH1 target genes identified by ChIP-seq were found highly enriched in genes showing expression changes after BACH1 knock-down, demonstrating the impact of BACH1 repression on transcription. In addition to known and new BACH1 targets involved in heme degradation (HMOX1, FTL, FTH1, ME1, SLC48A1) and redox regulation (GCLC, GCLM, SLC7A11), we also discovered BACH1 target genes effecting cell cycle and apoptosis pathways (ITPR2, CALM1, SQSTM1, TFE3, EWSR1, CDK6, BCL2L11, MAFG) as well as subcellular transport processes (CLSTN1, PSAP, MAPT, vault RNA). The newly identified impact of BACH1 on genes involved in neurodegenerative processes and proliferation provides an interesting basis for future dissection of BACH1-mediated gene repression in neurodegeneration and virus-induced cancerogenesis.
Project description:The transcriptional repressors BCL6 and BACH2 are crucial regulators of germinal center (GC) B-cell fate, and are known to interact and repress transcription of PRDM1, a key driver of plasma cell differentiation. How these factors cooperate is not fully understood. Herein we show that while GC formation is only minimally impaired in Bcl6+/- or Bach2+/- mice, double heterozygous Bcl6+/-Bach2+/- mice exhibit profound reduction in GC formation. Splenic B-cells from Bcl6+/- Bach2+/- mice display accelerated plasmacytic differentiation and high expression of key plasma cell genes such as Prdm1, Xbp1 and CD138. ChIP-seq revealed that in B-cells BACH2 is mostly bound to genes together with its heterodimer partner MAFK. The BACH2-MAFK complex binds to sets of genes known to be involved in the GC response, 60% of which are also targets of BCL6. Approximately 30% of BACH2 peaks overlap with BCL6 including cis-regulatory sequences of the PRDM1 gene. BCL6 also modulates BACH2 protein stability and their protein levels are positively correlated in GC B-cells. Therefore, BCL6 and BACH2 cooperate to orchestrate gene expression patterning in GC B cells through both transcriptional and biochemical mechanisms, which collectively determine the proper initiation and timing of terminal differentiation. ChIP-seq using P18 antibodies in OCI-Ly7 cells