RESUMEN
Acute myeloid leukemia (AML) is a heterogeneous cell population comprising genetically diverse sub-clones with significant differences in properties that vary from one patient to another. Since AML properties are similar to those of hematopoietic stem and myeloid cells, bone marrow as an organ responsible for the survival of AML-initiating cells has been proposed to be able to cause relapse following chemotherapy. Therefore, establishing in vivo experimental systems is critical for understanding the properties of AML cells and developing therapeutic strategies. In this review, the history, advantages, and disadvantages of mouse leukemia models wherein mouse cells are transformed by oncogenic events, including xenograft mice in which human AML cells are transplanted into immunodeficient mice, were introduced. Following which I described the development of chimeric antigen receptor cell therapy using human cytokines expressing the AML xenograft mice.
Asunto(s)
Leucemia Mieloide Aguda , Receptores Quiméricos de Antígenos , Animales , Citocinas , Humanos , Inmunoterapia Adoptiva , Leucemia Mieloide Aguda/patología , Ratones , Modelos Animales , Linfocitos TRESUMEN
The extracellular matrix (ECM) is the basis for virtually all cellular processes and is also related to tumor metastasis. Fibronectin (FN), a major ECM macromolecule expressed by different cell types and also present in plasma, consists of multiple functional modules that bind to ECM-associated, plasma, and cell-surface proteins such as integrins and FN itself, thus ensuring its cell-adhesive and modulatory role. Here we show that FN constitutes an immune checkpoint. Thus, FN was identified as a physiological ligand for a tumor/leukemia/lymphoma- as well as autoimmune-associated checkpoint, ILT3/LILRB4 (B4, CD85k). Human B4 and the murine ortholog, gp49B, bound FN with sub-micromolar affinities as assessed by bio-layer interferometry. The major B4-binding site in FN was located at the N-terminal 30-kDa module (FN30), which is apart from the major integrin-binding site present at the middle of the molecule. Blockade of B4-FN binding such as with B4 antibodies or a recombinant FN30-Fc fusion protein paradoxically ameliorated autoimmune disease in lupus-prone BXSB/Yaa mice. The unexpected nature of the B4-FN checkpoint in autoimmunity is discussed, referring to its potential role in tumor immunity.
Asunto(s)
Enfermedades Autoinmunes/metabolismo , Fibronectinas/metabolismo , Glicoproteínas de Membrana/metabolismo , Receptores Inmunológicos/metabolismo , Animales , Enfermedades Autoinmunes/inmunología , Autoinmunidad/inmunología , Comunicación Celular/inmunología , Línea Celular Tumoral , Células Cultivadas , Fibronectinas/inmunología , Células Endoteliales de la Vena Umbilical Humana/inmunología , Células Endoteliales de la Vena Umbilical Humana/metabolismo , Humanos , Leucocitos Mononucleares/inmunología , Leucocitos Mononucleares/metabolismo , Glicoproteínas de Membrana/inmunología , Ratones , Fagocitosis/inmunología , Células RAW 264.7 , Receptores Inmunológicos/inmunología , Células THP-1/inmunología , Células THP-1/metabolismoRESUMEN
Elucidation of how the differentiation of hematopoietic stem and progenitor cells (HSPCs) is reconfigured in response to the environment is critical for understanding the biology and disorder of hematopoiesis. Here we found that the transcription factors (TFs) Bach2 and Bach1 promoted erythropoiesis by regulating heme metabolism in committed erythroid cells to sustain erythroblast maturation and by reinforcing erythroid commitment at the erythro-myeloid bifurcation step. Bach TFs repressed expression of the gene encoding the transcription factor C/EBPß, as well as that of its target genes encoding molecules important for myelopoiesis and inflammation; they achieved the latter by binding to their regulatory regions also bound by C/EBPß. Lipopolysaccharide diminished the expression of Bach TFs in progenitor cells and promoted myeloid differentiation. Overexpression of Bach2 in HSPCs promoted erythroid development and inhibited myelopoiesis. Knockdown of BACH1 or BACH2 in human CD34+ HSPCs impaired erythroid differentiation in vitro. Thus, Bach TFs accelerate erythroid commitment by suppressing the myeloid program at steady state. Anemia of inflammation and myelodysplastic syndrome might involve reduced activity of Bach TFs.
Asunto(s)
Anemia/metabolismo , Factores de Transcripción con Cremalleras de Leucina de Carácter Básico/metabolismo , Eritropoyesis/fisiología , Anemia/etiología , Animales , Diferenciación Celular/fisiología , Células Eritroides/citología , Células Eritroides/metabolismo , Humanos , Infecciones/complicaciones , Lipopolisacáridos/toxicidad , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Síndromes Mielodisplásicos/etiología , Síndromes Mielodisplásicos/metabolismoRESUMEN
BTB and CNC homology 2 (Bach2) is a transcriptional repressor that is required for the formation of the germinal center (GC) and reactions, including class switch recombination and somatic hypermutation of Ig genes in B cells, within the GC. Although BCR-induced proliferation is essential for GC reactions, the function of Bach2 in regulating B cell proliferation has not been elucidated. In this study, we demonstrate that Bach2 is required to sustain high levels of B cell proliferation in response to BCR signaling. Following BCR engagement in vitro, B cells from Bach2-deficient (Bach2-/-) mice showed lower incorporation of BrdU and reduced cell cycle progression compared with wild-type cells. Bach2-/- B cells also underwent increased apoptosis, as evidenced by an elevated frequency of sub-G1 cells and early apoptotic cells. Transcriptome analysis of BCR-engaged B cells from Bach2-/- mice revealed reduced expression of the antiapoptotic gene Bcl2l1 encoding Bcl-xL and elevated expression of cyclin-dependent kinase inhibitor (CKI) family genes, including Cdkn1a, Cdkn2a, and Cdkn2b Reconstitution of Bcl-xL expression partially rescued the proliferation defect of Bach2-/- B cells. Chromatin immunoprecipitation experiments showed that Bach2 bound to the CKI family genes, indicating that these genes are direct repression targets of Bach2. These findings identify Bach2 as a requisite factor for sustaining high levels of BCR-induced proliferation, survival, and cell cycle progression, and it promotes expression of Bcl-xL and repression of CKI genes. BCR-induced proliferation defects may contribute to the impaired GC formation observed in Bach2-/- mice.
Asunto(s)
Linfocitos B/inmunología , Factores de Transcripción con Cremalleras de Leucina de Carácter Básico/inmunología , Activación de Linfocitos/inmunología , Animales , Factores de Transcripción con Cremalleras de Leucina de Carácter Básico/metabolismo , Proliferación Celular , Proteínas Inhibidoras de las Quinasas Dependientes de la Ciclina/inmunología , Ratones , Ratones Noqueados , Receptores de Antígenos de Linfocitos B/inmunologíaRESUMEN
Plasma cells (PCs) acquiring long lifespans in the bone marrow (BM) play a pivotal role in the humoral arm of immunological memory. The PCs reside in a special BM niche and produce antibodies against past-encountered pathogens or vaccine components for a long time. In BM, cysteine-X-cysteine (CXC) chemokine receptor type 4 (CXCR4)-expressing PCs and myeloid cells such as dendritic cells are attracted to and held by CXC chemokine ligand 12 (CXCR12)-secreting stromal cells, where survival of the PCs is supported by soluble factors such as IL-6 and APRIL (a proliferation-inducing ligand) produced by neighboring myeloid cells. Although these stromal cells are also supposed to be involved in the support of the survival and antibody production, the full molecular mechanism has not been clarified yet. Here, we show that BM PDGFRα+Sca-1+-enriched mesenchymal stem cells (MSCs), which can contribute as stromal cells for hematopoietic stem cells, also support in vitro survival of and antibody production by BM PCs. IL-6 produced by MSCs was found to be involved in the support. Immunohistochemistry of BM sections suggested a co-localization of a minor population of PCs with PDGFRα+Sca-1+ MSCs in the BM. We also found that the sort-purified MSC preparation was composed of multiple cell groups with different gene expression profiles, as found on single-cell RNA sequencing, to which multiple roles in the in vitro PC support could be attributed.
Asunto(s)
Formación de Anticuerpos , Antígenos Ly/metabolismo , Médula Ósea/metabolismo , Interleucina-6/metabolismo , Proteínas de la Membrana/metabolismo , Células Madre Mesenquimatosas/metabolismo , Células Plasmáticas/citología , Células Plasmáticas/inmunología , Receptor alfa de Factor de Crecimiento Derivado de Plaquetas/metabolismo , Animales , Supervivencia Celular , Células Cultivadas , Ratones , Ratones Endogámicos C57BL , Ratones NoqueadosRESUMEN
The capacity of the liver to regenerate is likely to be encoded as a plasticity of molecular networks within the liver. By applying a combination of comprehensive analyses of the epigenome, transcriptome, and proteome, we herein depict the molecular landscape of liver regeneration. We demonstrated that histone H3 Lys-4 was trimethylated at the promoter regions of many loci, among which only a fraction, including cell-cycle-related genes, were transcriptionally up-regulated. A cistrome analysis guided by the histone methylation patterns and the transcriptome identified FOXM1 as the key transcription factor promoting liver regeneration, which was confirmed in vitro using a hepatocarcinoma cell line. The promoter regions of cell-cycle-related genes and Foxm1 acquired higher levels of trimethylated histone H3 Lys-4, suggesting that epigenetic regulations of these key regulatory genes define quiescence and regeneration of the liver cells. A quantitative proteome analysis of the regenerating liver revealed that conditional protein degradation also mediated regeneration-specific protein expression. These sets of informational resources should be useful for further investigations of liver regeneration.
Asunto(s)
Regulación de la Expresión Génica , Histonas/química , Regeneración Hepática , Hígado/metabolismo , ARN Mensajero/metabolismo , Secuencias de Aminoácidos , Animales , Carcinoma Hepatocelular/metabolismo , Línea Celular Tumoral , Proliferación Celular , Epigénesis Genética , Proteína Forkhead Box M1/metabolismo , Neoplasias Hepáticas/metabolismo , Lisina/química , Masculino , Metilación , Ratones , Ratones Endogámicos C57BL , Regiones Promotoras Genéticas , Proteoma/metabolismo , TranscriptomaRESUMEN
Hematopoietic stem cell and multipotent progenitor (MPP) commitment can be tuned in response to an infection so that their differentiation is biased toward myeloid cells. Here, we find that Bach2, which inhibits myeloid differentiation in common lymphoid progenitors, represses a cohort of myeloid genes and activates those linked to lymphoid function. Bach2 repressed both Cebpb and its target Csf1r, encoding C/EBPß and macrophage colony-stimulating factor receptor (M-CSFr), respectively, whereas C/EBPß repressed Bach2 and activated Csf1r. Bach2 and C/EBPß further bound to overlapping regulatory regions at their myeloid target genes, suggesting the presence of a gene regulatory network (GRN) with mutual repression between these factors and a feedforward loop leading to myeloid gene regulation. Lipopolysaccharide reduced the expression of Bach2, resulting in enhanced myeloid differentiation. The Bach2-C/EBPß GRN pathway thus tunes MPP commitment to myeloid and lymphoid lineages both under normal conditions and after infection.
Asunto(s)
Factores de Transcripción con Cremalleras de Leucina de Carácter Básico/metabolismo , Proteínas Potenciadoras de Unión a CCAAT/metabolismo , Redes Reguladoras de Genes , Células Madre Hematopoyéticas/metabolismo , Células Madre Multipotentes/metabolismo , Animales , Sitios de Unión , Diferenciación Celular/genética , Regulación hacia Abajo/genética , Elementos de Facilitación Genéticos/genética , Células Madre Hematopoyéticas/citología , Células Progenitoras Linfoides/citología , Células Progenitoras Linfoides/metabolismo , Ratones Endogámicos C57BL , Células Madre Multipotentes/citología , Células Progenitoras Mieloides/citología , Células Progenitoras Mieloides/metabolismo , Unión ProteicaRESUMEN
Bach2 is a transcription factor which represses its target genes and plays important roles in the differentiation of B and T lymphoid cells. Bach2-deficient (KO) mice develop severe pulmonary alveolar proteinosis, which is associated with increased numbers of granulocytes and T cells. Bach2 is essential for the regulation of T cells, but its role in the regulation of granulocytes is not clear. Here, we observed increased numbers of eosinophils but not neutrophils in the bone marrow, spleen, peripheral blood, and bronchoalveolar lavage fluids of Bach2 KO mice compared with those of wild-type (WT) mice. Upon co-transplantation of the bone marrow cells from CD45.2 Bach2 KO and CD45.1/CD45.2 double-positive WT mice to irradiated WT CD45.1/CD45.2 mice, the reconstituted numbers of eosinophils were similar between Bach2 KO and WT cells. These results showed that the deficiency of Bach2 in eosinophils did not directly drive the differentiation of eosinophils. To investigate the effect of Bach2 KO CD4+ T cells upon eosinophils, we analyzed Rag2/Bach2-double deficient (dKO) mice which lack lymphocytes including CD4+ T cells. Rag2/Bach2 dKO mice did not show any increase in the numbers of eosinophils. Importantly, Bach2 KO mice showed an increase of interleukin-5 (Il-5) in the sera compared with WT mice. These results suggest that up-regulated functions of CD4+ T cells including secretion of Il-5 resulted in proliferation and/or migration to peripheral tissues of eosinophils in Bach2 KO mice. We propose that Bach2 controls homeostasis of eosinophils via restricting the production of Il-5 in CD4+ T cells.
Asunto(s)
Factores de Transcripción con Cremalleras de Leucina de Carácter Básico/metabolismo , Eosinófilos/metabolismo , Homeostasis , Linfocitos T Colaboradores-Inductores/metabolismo , Animales , Recuento de Células , Depleción Linfocítica , Ratones Endogámicos C57BL , Ratones NoqueadosRESUMEN
Iron plays the central role in oxygen transport by erythrocytes as a constituent of heme and hemoglobin. The importance of iron and heme is also to be found in their regulatory roles during erythroblast maturation. The transcription factor Bach1 may be involved in their regulatory roles since it is deactivated by direct binding of heme. To address whether Bach1 is involved in the responses of erythroblasts to iron status, low iron conditions that induced severe iron deficiency in mice were established. Under iron deficiency, extensive gene expression changes and mitophagy disorder were induced during maturation of erythroblasts. Bach1-/- mice showed more severe iron deficiency anemia in the developmental phase of mice and a retarded recovery once iron was replenished when compared with wild-type mice. In the absence of Bach1, the expression of globin genes and Hmox1 (encoding heme oxygenase-1) was de-repressed in erythroblasts under iron deficiency, suggesting that Bach1 represses these genes in erythroblasts under iron deficiency to balance the levels of heme and globin. Moreover, an increase in genome-wide DNA methylation was observed in erythroblasts of Bach1-/- mice under iron deficiency. These findings reveal the principle role of iron as a regulator of gene expression in erythroblast maturation and suggest that the iron-heme-Bach1 axis is important for a proper adaptation of erythroblast to iron deficiency to avoid toxic aggregates of non-heme globin.
Asunto(s)
Adaptación Biológica , Anemia Ferropénica/metabolismo , Factores de Transcripción con Cremalleras de Leucina de Carácter Básico/metabolismo , Eritroblastos/metabolismo , Hemo/metabolismo , Hierro/metabolismo , Anemia Ferropénica/etiología , Animales , Factores de Transcripción con Cremalleras de Leucina de Carácter Básico/genética , Células Sanguíneas/metabolismo , Células de la Médula Ósea/metabolismo , Análisis por Conglomerados , Metilación de ADN , Dieta , Modelos Animales de Enfermedad , Perfilación de la Expresión Génica , Regulación de la Expresión Génica , Globinas/genética , Globinas/metabolismo , Ratones , Ratones Noqueados , Mitofagia/genética , Unión Proteica , Transducción de SeñalRESUMEN
Plasmablasts and plasma cells (PBs and PCs) producing pathogenic auto-antibodies in patients with systemic autoimmune diseases could be a better target for specific therapies for the disease than general immunosuppression or pan- or activated B-cell targeting. Our previous study indicated that leukocyte immunoglobulin-like receptor (LILR) B4 (B4, also known as ILT3/LIR-5/CD85k), a tolerogenic receptor in antigen-presenting cells, is ectopically expressed on the PB/PC surface in healthy individuals. Here, we show that the enlarged population size of PBs/PCs with augmented B4 expression is characteristic in non-treated systemic lupus erythematosus (SLE). Paradoxically, the transcription frequency of the anti-double-strand DNA immunoglobulin-coding VH sequence in the B4+ population of non-treated SLE was significantly higher than that in B4- cells. B4+ and B4- PBs/PCs were suggested to be developmentally equivalent based on the simultaneous generation of these populations upon activation of memory B cells in vitro B4 expression was found to be induced efficiently by IL-2, while IFN-α effectively induced B4+ PBs/PCs in vitro Utilizing the elevated B4 will support opening a new avenue for identifying the mechanism for generation of, and additional molecular markers for, pathogenic cells.
Asunto(s)
Autoanticuerpos/inmunología , Tolerancia Inmunológica/inmunología , Lupus Eritematoso Sistémico/inmunología , Lupus Eritematoso Sistémico/patología , Células Plasmáticas/inmunología , Receptores de Superficie Celular/inmunología , Adolescente , Adulto , Anciano , Femenino , Humanos , Masculino , Glicoproteínas de Membrana , Persona de Mediana Edad , Receptores Inmunológicos , Adulto JovenRESUMEN
Pulmonary alveolar proteinosis (PAP) is a disease resulting from a dysfunction of the alveolar macrophages (AMs) where excess surfactant protein accumulates in the alveolar spaces. We previously reported that Bach2 KO mice developed PAP due to a defect in the handling of lipids by AMs. To investigate the functions of Bach1 and Bach2, which are regulated by oxidative stress, in the AMs and in lung homeostasis, we generated mice that lacked both Bach1 and Bach2 (Bach1/2 DKO mice). The Bach1/2 DKO mice showed more severe PAP phenotype than Bach2 KO mice with abnormal AMs, whereas the Bach1 KO mice did not develop any pulmonary disease. The PAP-like disease in the Bach1/2 DKO and Bach2 KO mice was not ameliorated by antioxidant, suggesting that ROS was not involved in the onset of PAP in the absence of Bach1 and Bach2. A microarray and a chromatin immunoprecipitation sequence analysis revealed that Bach1 and Bach2 directly repress the common set of genes involved in the inflammatory response, and that Bach2 is a major contributor to this repression. These results suggest that Bach1 and Bach2 work in a complementary manner to maintain the normal function of the AMs and surfactant homeostasis in the lung.
Asunto(s)
Factores de Transcripción con Cremalleras de Leucina de Carácter Básico/metabolismo , Pulmón/metabolismo , Macrófagos Alveolares/metabolismo , Surfactantes Pulmonares/metabolismo , Animales , Factores de Transcripción con Cremalleras de Leucina de Carácter Básico/genética , Macrófagos Alveolares/citología , Ratones , Ratones NoqueadosRESUMEN
Dendritic cells (DCs) are critical immune response regulators; however, the mechanism of DC differentiation is not fully understood. Heterozygous germ line GATA2 mutations induce GATA2-deficiency syndrome, characterized by monocytopenia, a predisposition to myelodysplasia/acute myeloid leukemia, and a profoundly reduced DC population, which is associated with increased susceptibility to viral infections, impaired phagocytosis, and decreased cytokine production. To define the role of GATA2 in DC differentiation and function, we studied Gata2 conditional knockout and haploinsufficient mice. Gata2 conditional deficiency significantly reduced the DC count, whereas Gata2 haploinsufficiency did not affect this population. GATA2 was required for the in vitro generation of DCs from Lin(-)Sca-1(+)Kit(+) cells, common myeloid-restricted progenitors, and common dendritic cell precursors, but not common lymphoid-restricted progenitors or granulocyte-macrophage progenitors, suggesting that GATA2 functions in the myeloid pathway of DC differentiation. Moreover, expression profiling demonstrated reduced expression of myeloid-related genes, including mafb, and increased expression of T-lymphocyte-related genes, including Gata3 and Tcf7, in Gata2-deficient DC progenitors. In addition, GATA2 was found to bind an enhancer element 190-kb downstream region of Gata3, and a reporter assay exhibited significantly reduced luciferase activity after adding this enhancer region to the Gata3 promoter, which was recovered by GATA sequence deletion within Gata3 +190. These results suggest that GATA2 plays an important role in cell-fate specification toward the myeloid vs T-lymphocyte lineage by regulating lineage-specific transcription factors in DC progenitors, thereby contributing to DC differentiation.
Asunto(s)
Diferenciación Celular/inmunología , Células Dendríticas/inmunología , Factor de Transcripción GATA2/inmunología , Animales , Diferenciación Celular/genética , Células Dendríticas/citología , Factor de Transcripción GATA2/genética , Factor de Transcripción GATA3/genética , Factor de Transcripción GATA3/inmunología , Factor Nuclear 1-alfa del Hepatocito/genética , Factor Nuclear 1-alfa del Hepatocito/inmunología , Ratones , Ratones Noqueados , Células Mieloides/citología , Células Mieloides/inmunología , Linfocitos T/citología , Linfocitos T/inmunologíaRESUMEN
The transcription repressor Bach2 is required for class switch recombination and somatic hypermutation of antibody genes in B cells, and proper development of effector and regulatory T cells. In addition, Bach2 and its related factor Bach1 promote B cell commitment of progenitor cells by repressing myeloid-related genes. Bach2 and the myeloid regulators C/EBPß and C/EBPα mutually repress their expression, forming a gene regulatory network (GRN) that dictates the process of lineage commitment. Bach2 forms another GRN with the plasma cell regulator Blimp-1, in which Bach2 and Blimp-1 mutually repress their expression. Since Bach2 expression is reduced in plasma cells, the repression of myeloid-related genes in B cells may be dissolved upon terminal differentiation of B cells to plasma cells. The Bach2 GRNs support the myeloid-based model of hematopoiesis. Myeloid-like characteristics suppressed or manifested in B cells by modifying differentiation trajectories of B and myeloid cells may be termed as 'inner myeloid' after the concept of 'inner fish'.
Asunto(s)
Linfocitos B/citología , Factores de Transcripción con Cremalleras de Leucina de Carácter Básico/fisiología , Cambio de Clase de Inmunoglobulina/fisiología , Linfocitos T/citología , Animales , Linfocitos B/inmunología , Proteína beta Potenciadora de Unión a CCAAT/metabolismo , Proteínas Potenciadoras de Unión a CCAAT/metabolismo , Diferenciación Celular , Regulación de la Expresión Génica/inmunología , Humanos , Linfocitos T/inmunologíaRESUMEN
Mature lymphoid cells express the transcription 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. Bach2(hi) 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.
Asunto(s)
Linfocitos B/citología , Factores de Transcripción con Cremalleras de Leucina de Carácter Básico/metabolismo , Diferenciación Celular/fisiología , Células Precursoras de Linfocitos B/citología , Transactivadores/metabolismo , Animales , Linfocitos B/metabolismo , Factores de Transcripción con Cremalleras de Leucina de Carácter Básico/genética , Linaje de la Célula , Separación Celular , Inmunoprecipitación de Cromatina , Ensayo de Cambio de Movilidad Electroforética , Citometría de Flujo , Regulación de la Expresión Génica/fisiología , Células Progenitoras Linfoides/citología , Células Progenitoras Linfoides/metabolismo , Linfopoyesis/fisiología , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Análisis de Secuencia por Matrices de Oligonucleótidos , Células Precursoras de Linfocitos B/metabolismo , Reacción en Cadena en Tiempo Real de la Polimerasa , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Transactivadores/genéticaRESUMEN
Bach2 is a basic region-leucine zipper (bZip) transcription factor that forms heterodimers with small Maf oncoproteins and binds to target genes, thus repressing their expression. Bach2 is required for class switch recombination (CSR) and somatic hypermutation (SHM) of immunoglobulin genes in activated B cells. Bach2 represses the expression of Prdm1 encoding Blimp-1 repressor and thereby inhibits terminal differentiation of B cells to plasma cells. This causes a delay in the induction of Prdm1, thereby securing a time window for the expression of Aicda encoding activation-induced cytidine deaminase (AID) required for both CSR and SHM. Based on the characteristics of a gene regulatory network (GRN) involving Bach2 and Prdm1 and its dynamics, a 'delay-driven diversity' model was introduced to explain the responses of activated B cells. Bach2 is also required for the proper differentiation and function of peripheral T cells. In the absence of Bach2, CD4(+) T cells show increased differentiation to effector cells producing higher levels of Th2-related cytokines, such as IL-4 and IL-10, and a reduction in the generation of regulatory T cells. Bach2 represses many genes in T cells, including Prdm1, suggesting that the Bach2-Prdm1 pathway is also important in maintaining the homeostasis of T cells. Furthermore, Bach2 is essential for the function of alveolar macrophages. Therefore, Bach2 orchestrates both acquired and innate immunity at multiple points. Its connection with disease is also reviewed in this report.
Asunto(s)
Linfocitos B/inmunología , Factores de Transcripción con Cremalleras de Leucina de Carácter Básico/metabolismo , Enfermedades del Sistema Inmune/inmunología , Células Plasmáticas/inmunología , Linfocitos T/inmunología , Animales , Factores de Transcripción con Cremalleras de Leucina de Carácter Básico/genética , Diferenciación Celular , Regulación de la Expresión Génica/inmunología , Redes Reguladoras de Genes/inmunología , Humanos , Cambio de Clase de Inmunoglobulina/genética , Proteína Oncogénica v-maf/metabolismo , Unión Proteica , Hipermutación Somática de Inmunoglobulina/genética , Balance Th1 - Th2RESUMEN
Oxidative stress contributes to both aging and tumorigenesis. The transcription factor Bach1, a regulator of oxidative stress response, augments oxidative stress by repressing the expression of heme oxygenase-1 (HO-1) gene (Hmox1) and suppresses oxidative stress-induced cellular senescence by restricting the p53 transcriptional activity. Here we investigated the lifelong effects of Bach1 deficiency on mice. Bach1-deficient mice showed longevity similar to wild-type mice. Although HO-1 was upregulated in the cells of Bach1-deficient animals, the levels of ROS in Bach1-deficient HSCs were comparable to those in wild-type cells. Bach1(-/-); p53(-/-) mice succumbed to spontaneous cancers as frequently as p53-deficient mice. Bach1 deficiency significantly altered transcriptome in the liver of the young mice, which surprisingly became similar to that of wild-type mice during the course of aging. The transcriptome adaptation to Bach1 deficiency may reflect how oxidative stress response is tuned upon genetic and environmental perturbations. We concluded that Bach1 deficiency and accompanying overexpression of HO-1 did not influence aging or p53 deficiency-driven tumorigenesis. Our results suggest that it is useful to target Bach1 for acute injury responses without inducing any apparent deteriorative effect.
Asunto(s)
Envejecimiento/metabolismo , Factores de Transcripción con Cremalleras de Leucina de Carácter Básico/deficiencia , Carcinogénesis/metabolismo , Carcinogénesis/patología , Hemo-Oxigenasa 1/metabolismo , Animales , Factores de Transcripción con Cremalleras de Leucina de Carácter Básico/metabolismo , Perfilación de la Expresión Génica , Regulación de la Expresión Génica , Redes Reguladoras de Genes , Células Madre Hematopoyéticas/metabolismo , Hígado/metabolismo , Hígado/patología , Longevidad , Ratones Endogámicos C57BL , Transcriptoma/genética , Proteína p53 Supresora de Tumor/deficiencia , Proteína p53 Supresora de Tumor/metabolismoRESUMEN
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.
Asunto(s)
Factores de Transcripción con Cremalleras de Leucina de Carácter Básico/metabolismo , Homeostasis , Macrófagos Alveolares/metabolismo , Surfactantes Pulmonares/metabolismo , Proteínas Represoras/metabolismo , Animales , Factores de Transcripción con Cremalleras de Leucina de Carácter Básico/deficiencia , Colesterol/metabolismo , Progresión de la Enfermedad , Disnea/complicaciones , Disnea/genética , Disnea/patología , Eosinófilos/metabolismo , Perfilación de la Expresión Génica , Regulación de la Expresión Génica , Factor Estimulante de Colonias de Granulocitos y Macrófagos/metabolismo , Células Madre Hematopoyéticas/metabolismo , Factores Reguladores del Interferón/metabolismo , Metabolismo de los Lípidos/genética , Macrófagos Peritoneales/metabolismo , Ratones , Fagocitosis , Fenotipo , Proteínas Proto-Oncogénicas/metabolismo , Proteinosis Alveolar Pulmonar/complicaciones , Proteinosis Alveolar Pulmonar/genética , Proteinosis Alveolar Pulmonar/patología , Transducción de Señal , Transactivadores/metabolismoRESUMEN
There are no primary immunodeficiency diseases linked to the Y chromosome, because the Y chromosome does not contain any vital genes. We have established a novel mouse strain in which all males lack B and NK cells and have Peyer's patch defects. By 10 wk of age, 100% of the males had evident immunodeficiencies. Mating these immunodeficient males with wild-type females on two different genetic backgrounds for several generations demonstrated that the immunodeficiency is linked to the Y chromosome and is inherited in a Mendelian fashion. Although multicolor fluorescence in situ hybridization analysis showed that the Y chromosome in the mutant male mice was one third shorter than that in wild-type males, exome sequencing did not identify any significant gene mutations. The precise molecular mechanisms are still unknown. Bone marrow chimeric analyses demonstrated that an intrinsic abnormality in bone marrow hematopoietic cells causes the B and NK cell defects. Interestingly, fetal liver cells transplanted from the mutant male mice reconstituted B and NK cells in lymphocyte-deficient Il2rg(-/-) recipient mice, whereas adult bone marrow transplants did not. Transducing the EBF gene, a master transcription factor for B cell development, into mutant hematopoietic progenitor cells rescued B cell but not NK cell development both in vitro and in vivo. These Y chromosome-linked immunodeficient mice, which have preferential B and NK cell defects, may be a useful model of lymphocyte development.
Asunto(s)
Linfocitos B/inmunología , Enfermedades Genéticas Ligadas al Cromosoma Y/genética , Enfermedades Genéticas Ligadas al Cromosoma Y/inmunología , Síndromes de Inmunodeficiencia/genética , Células Asesinas Naturales/inmunología , Traslado Adoptivo , Animales , Modelos Animales de Enfermedad , Citometría de Flujo , Genes Ligados a Y/genética , Genes Ligados a Y/inmunología , Síndromes de Inmunodeficiencia/inmunología , Masculino , Ratones , Ratones Endogámicos C57BL , Reacción en Cadena en Tiempo Real de la Polimerasa , Reacción en Cadena de la Polimerasa de Transcriptasa InversaRESUMEN
OBJECTIVE: Reducing inflammation and osteoclastogenesis by heme oxygenase 1 (HO-1) induction could be beneficial in the treatment of rheumatoid arthritis (RA). However, the function of HO-1 in bone metabolism remains unclear. This study was undertaken to clarify the effects of HO-1 and its repressor Bach1 in osteoclastogenesis. METHODS: In vitro osteoclastogenesis was compared in Bach1-deficient and wild-type mice. Osteoclasts (OCs) were generated from bone marrow-derived macrophages by stimulation with macrophage colony-stimulating factor and RANKL. Osteoclastogenesis was assessed by tartrate-resistant acid phosphatase staining and expression of OC-related genes. Intracellular signal pathways in OC precursors were also assessed. HO-1 short hairpin RNA (shRNA) was transduced into Bach1(-/-) mouse bone marrow-derived macrophages to examine the role of HO-1 in osteoclastogenesis. In vivo inflammatory bone loss was evaluated by local injection of tumor necrosis factor α (TNFα) into calvaria. RESULTS: Transcription of HO-1 was down-regulated by stimulation with RANKL in the early stage of OC differentiation. Bach1(-/-) mouse bone marrow-derived macrophages were partially resistant to the RANKL-dependent HO-1 reduction and showed impaired osteoclastogenesis, which was associated with reduced expression of RANK and components of the downstream TNF receptor-associated factor 6/c-Fos/NF-ATc1 pathway as well as reduced expression of Blimp1. Treatment with HO-1 shRNA increased the number of OCs and expression of OC-related genes except for the Blimp1 gene during in vitro osteoclastogenesis from Bach1(-/-) mouse bone marrow-derived macrophages. TNFα-induced bone destruction was reduced in Bach1(-/-) mice in vivo. CONCLUSION: The present findings demonstrate that Bach1 regulates osteoclastogenesis under inflammatory conditions, via both HO-1-dependent and HO-1-independent mechanisms. Bach1 may be worthy of consideration as a target for treatment of inflammatory bone loss in diseases including RA.