Project description:Macrophages are central in regulating iron homeostasis. Transcription repressor Bach2 regulates by heme. Here we investigated the relationship between heme-regulated Bach2 and macrophage in bone marrow. We identified RFP-positive and negative macrophage were in bone marrow. We found that RFP-positive macrophage related with iron-heme homeostasis maintenance and RPF-negative population related with immune response. In RFP positive macrophage, we also found the lysosomal heme transporter hrg-1 was Bach2 direct target gene. Our results suggest that the function of the bone marrow macrophage alters according to expression of Bach2.
Project description:Macrophages are central in regulating iron homeostasis. Transcription repressor Bach1 regulates by heme. Here we investigated the relationship between heme-regulated Bach1 and bone marrow derived macrophage. We found that Bach1 KO macrophage showed that up-regulated genes were the process that iron-heme homeostasis and maintenance related gene compared with WT. Our results suggest that Bach1 expression is important to the heme homeostasis and maintenance in the bone marrow derived macrophage.
Project description:Macrophages are central in regulating iron homeostasis. Transcription repressor Bach2 regulates by heme. Here we investigated the relationship between heme-regulated Bach2 and macrophage in spleen. We found that gene expression were not many change between WT and Bach2 knock out mice in red-pulp macrophage.Our results suggest that the function of the red-pulp macrophage is not dependent on according to expression of Bach2.
Project description:Splenic red pulp macrophages (RPM) degrade senescent erythrocytes and recycle heme-associated iron. The transcription factor Spic is selectively expressed by RPM and is required for their development, but the physiologic stimulus inducing Spic is unknown. Here, we report that Spic also regulated the development of F4/80+VCAM+ bone marrow macrophages (BMM) and that Spic expression in BMM and RPM development was induced by heme, a metabolite of erythrocyte degradation. Pathologic hemolysis induced loss of RPM and BMM due to excess heme but induced Spic in monocytes to generate new RPM and BMM. Spic expression in monocytes was constitutively inhibited by the transcriptional repressor Bach1. Heme induced proteasome-dependent BACH1 degradation and rapid Spic derepression. Further, cysteine-proline dipeptide motifs in BACH1 that mediate heme-dependent degradation were necessary for Spic induction by heme. These findings are the first example of metabolite-driven differentiation of a tissue-resident macrophage subset and provide new insight into iron homeostasis. Bone marrow derived macrophages were generated in vitro by culturing WT and Bach1 knock out bone marrow in the presence of GM-CSF and their global gene expression pattern were compared in the presence or absence of heme at the various indicated time points after treatment. GMP and MPP populations were sorted from fetal liver chimeras and pooled by donor genotype. RNA was isolated using an RNAqueous-Micro Kit (Ambion) and submitted for amplification, labeling and hybridization. Expression values were analyzed after RMA quantile normalization using ArrayStar software (DNASTAR).
Project description:Splenic red pulp macrophages (RPM) degrade senescent erythrocytes and recycle heme-associated iron. The transcription factor Spic is selectively expressed by RPM and is required for their development, but the physiologic stimulus inducing Spic is unknown. Here, we report that Spic also regulated the development of F4/80+VCAM+ bone marrow macrophages (BMM) and that Spic expression in BMM and RPM development was induced by heme, a metabolite of erythrocyte degradation. Pathologic hemolysis induced loss of RPM and BMM due to excess heme but induced Spic in monocytes to generate new RPM and BMM. Spic expression in monocytes was constitutively inhibited by the transcriptional repressor Bach1. Heme induced proteasome-dependent BACH1 degradation and rapid Spic derepression. Further, cysteine-proline dipeptide motifs in BACH1 that mediate heme-dependent degradation were necessary for Spic induction by heme. These findings are the first example of metabolite-driven differentiation of a tissue-resident macrophage subset and provide new insight into iron homeostasis. Bone marrow derived macrophages were generated in vitro by culturing WT and Bach1 knock out bone marrow in the presence of GM-CSF and their global gene expression pattern were compared in the presence or absence of heme at the various indicated time points after treatment.
Project description:Splenic red pulp macrophages (RPM) degrade senescent erythrocytes and recycle heme-associated iron. The transcription factor Spic is selectively expressed by RPM and is required for their development, but the physiologic stimulus inducing Spic is unknown. Here, we report that Spic also regulated the development of F4/80+VCAM+ bone marrow macrophages (BMM) and that Spic expression in BMM and RPM development was induced by heme, a metabolite of erythrocyte degradation. Pathologic hemolysis induced loss of RPM and BMM due to excess heme but induced Spic in monocytes to generate new RPM and BMM. Spic expression in monocytes was constitutively inhibited by the transcriptional repressor Bach1. Heme induced proteasome-dependent BACH1 degradation and rapid Spic derepression. Further, cysteine-proline dipeptide motifs in BACH1 that mediate heme-dependent degradation were necessary for Spic induction by heme. These findings are the first example of metabolite-driven differentiation of a tissue-resident macrophage subset and provide new insight into iron homeostasis. Global gene expression pattern of bone marrow-derived macrophages generated with GM-CSF in vitro and treated with heme were compared to those treated with vehicle at 6 hours, 24 hours, and 72 hours after treatment.
Project description:Splenic red pulp macrophages (RPM) degrade senescent erythrocytes and recycle heme-associated iron. The transcription factor Spic is selectively expressed by RPM and is required for their development, but the physiologic stimulus inducing Spic is unknown. Here, we report that Spic also regulated the development of F4/80+VCAM+ bone marrow macrophages (BMM) and that Spic expression in BMM and RPM development was induced by heme, a metabolite of erythrocyte degradation. Pathologic hemolysis induced loss of RPM and BMM due to excess heme but induced Spic in monocytes to generate new RPM and BMM. Spic expression in monocytes was constitutively inhibited by the transcriptional repressor Bach1. Heme induced proteasome-dependent BACH1 degradation and rapid Spic derepression. Further, cysteine-proline dipeptide motifs in BACH1 that mediate heme-dependent degradation were necessary for Spic induction by heme. These findings are the first example of metabolite-driven differentiation of a tissue-resident macrophage subset and provide new insight into iron homeostasis. Global gene expression pattern of bone marrow-derived macrophages generated with GM-CSF in vitro and treated with heme were compared to those treated with vehicle at 6 hours, 24 hours, and 72 hours after treatment. GM-CSF cultures of Spic(igfp/igfp) BM cells were treated with heme (80 µm) or vehicle after 6 days in culture. Adherent fraction of cells were harvested 6 hours, 24 hours, and 72 hours after treatment and RNA was isolated using an RNeasy mini kit (Qiagen) and submitted for amplification, labeling and hybridization. Expression values were analyzed after RMA quantile normalization using ArrayStar software (DNASTAR).
Project description:Pulmonary alveolar proteinosis (PAP) results from a dysfunction of alveolar macrophages (AMs), chiefly due to disruptions in the signaling of granulocyte macrophage colony-stimulating factor (GM-CSF). We found that mice deficient for the B lymphoid transcription repressor BTB and CNC homology 2 (Bach2) developed PAP-like accumulation of surfactant proteins in the lungs. Bach2 was expressed in AMs, and Bach2-deficient AMs showed alterations in lipid handling in comparison with wild-type (WT) cells. Although Bach2-deficient AMs showed a normal expression of the genes involved in the GM-CSF signaling, they showed an altered expression of the genes involved in chemotaxis, lipid metabolism, and alternative M2 macrophage activation with increased expression of Ym1 and arginase-1, and the M2 regulator Irf4. Peritoneal Bach2-deficient macrophages showed increased Ym1 expression when stimulated with interleukin-4. More eosinophils were present in the lung and peritoneal cavity of Bach2-deficient mice compared with WT mice. The PAP-like lesions in Bach2-deficient mice were relieved by WT bone marrow transplantation even after their development, confirming the hematopoietic origin of the lesions. These results indicate that Bach2 is required for the functional maturation of AMs and pulmonary homeostasis, independently of the GM-CSF signaling. WT (n=8) and Bach2KO (n=3) AMs. One expreriment was performed.