RESUMO
The importance of Notch signaling to maintain CD8- dendritic cells (DCs) in the spleen has recently been revealed. However, the ligand responsible for this Notch signaling has not been determined yet. In this study, we demonstrated that blocking of Delta-like (Dll) 1 alone had no significant effect on the maintenance of CD8- DCs while marginal zone (MZ) B cells were significantly reduced in the spleen of mice. On the other hand, blocking of Dll1, Dll4, Jagged1 and Jagged2 significantly decreased CD8- DCs. All these Notch ligands are expressed predominantly in the red pulp of the spleen where CD8- DCs reside. These results indicate a differential regulation of CD8- DCs and MZ B cells by Notch ligands in the spleen.
Assuntos
Linfócitos B/metabolismo , Proteínas de Ligação ao Cálcio/metabolismo , Células Dendríticas Foliculares/metabolismo , Peptídeos e Proteínas de Sinalização Intercelular/metabolismo , Proteínas de Membrana/metabolismo , Receptores Notch/metabolismo , Baço/metabolismo , Animais , Anticorpos Bloqueadores/administração & dosagem , Linfócitos B/imunologia , Antígenos CD8 , Proteínas de Ligação ao Cálcio/genética , Proteínas de Ligação ao Cálcio/imunologia , Contagem de Células , Células Dendríticas Foliculares/imunologia , Regulação da Expressão Gênica , Peptídeos e Proteínas de Sinalização Intercelular/genética , Peptídeos e Proteínas de Sinalização Intercelular/imunologia , Interleucina-12/metabolismo , Proteína Jagged-1 , Proteína Jagged-2 , Proteínas de Membrana/genética , Proteínas de Membrana/imunologia , Camundongos , Camundongos Endogâmicos C57BL , Receptores Notch/genética , Receptores Notch/imunologia , Proteínas Serrate-Jagged , Transdução de Sinais/imunologia , Baço/imunologia , Baço/patologiaRESUMO
OTT/RBM15-BSAC/MAL/MKL1/MRTF-A was identified as a fusion transcript generated by t(1;22)(p13;q13) in acute megakaryoblastic leukemia. Previous studies have shown that BSAC (basic, SAP, and coiled-coil domain) activates the promoters containing CArG boxes via interaction with serum response factor, and OTT (one twenty-two) negatively regulates the development of megakaryocytes and myeloid cells. However, the mechanism by which OTT-BSAC promotes leukemia is largely unknown. Here we show that OTT-BSAC, but not BSAC or OTT strongly activates several promoters containing a transcription factor Yin Yang 1-binding sequence. In addition, although BSAC predominantly localizes in the cytoplasm and its nuclear translocation is considered to be regulated by the Rho-actin signaling pathway, OTT-BSAC exclusively localizes in the nucleus. Moreover, OTT interacts with histone deacetylase 3, but this interaction is abolished in OTT-BSAC. Collectively, these functional and spatial changes of OTT and BSAC caused by the fusion might perturb their functions, culminating in the development of acute megakaryoblastic leukemia.
Assuntos
Núcleo Celular/metabolismo , Proteínas de Ligação a DNA/metabolismo , Leucemia Megacarioblástica Aguda/metabolismo , Proteínas de Fusão Oncogênica/metabolismo , Proteínas de Ligação a RNA/metabolismo , Elementos de Resposta , Transcrição Gênica , Transporte Ativo do Núcleo Celular/genética , Linhagem Celular Tumoral , Núcleo Celular/genética , Proteínas de Ligação a DNA/genética , Histona Desacetilases/genética , Histona Desacetilases/metabolismo , Humanos , Leucemia Megacarioblástica Aguda/genética , Megacariócitos/metabolismo , Proteínas de Fusão Oncogênica/genética , Estrutura Terciária de Proteína/genética , Proteínas de Ligação a RNA/genética , Elementos de Resposta/genética , Transativadores , Transcrição Gênica/genética , Regulação para Cima/genética , Fator de Transcrição YY1/genética , Fator de Transcrição YY1/metabolismoRESUMO
Notch2 and Delta-like 1 (Dll1) have been implicated in the development of marginal zone B (MZB) cells. In the present study, we characterized the expression and function of mouse Notch receptors and ligands in the spleen by using newly generated mAbs. Although Notch2 was expressed on both B and T cells in the spleen, the highest expression was observed on precursors of marginal zone B and MZB cells. Dll1 was expressed on macrophage and erythroblasts in the red pulp, but not on B cells or marginal zone macrophage. Administration of a blocking mAb against Dll1 not only blocked the development of MZB cells in juvenile mice but also gradually depleted the pre-established MZB cells in adult mice, indicating a critical role for Dll1 in the maintenance of MZB cells in the spleen of normal mice. Interestingly, Dll1 was not necessary for the maintenance of MZB cells in lupus-prone (NZB x NZW) F1 mice particularly after the onset of the disease, suggesting that the Dll1 independence may be a feature of dysregulated MZB cells producing auto-antibodies.
Assuntos
Autoimunidade/imunologia , Linfócitos B/imunologia , Peptídeos e Proteínas de Sinalização Intracelular/imunologia , Peptídeos e Proteínas de Sinalização Intracelular/metabolismo , Proteínas de Membrana/imunologia , Proteínas de Membrana/metabolismo , Animais , Anticorpos Bloqueadores/farmacologia , Autoanticorpos/biossíntese , Linfócitos B/metabolismo , Linfócitos B/patologia , Diferenciação Celular/imunologia , Modelos Animais de Doenças , Regulação da Expressão Gênica/imunologia , Homeostase/imunologia , Peptídeos e Proteínas de Sinalização Intracelular/antagonistas & inibidores , Lúpus Eritematoso Sistêmico/imunologia , Proteínas de Membrana/antagonistas & inibidores , Camundongos , Camundongos Endogâmicos NZB , Receptor Notch2/imunologia , Receptor Notch2/metabolismo , Baço/imunologia , Baço/metabolismo , Baço/patologiaRESUMO
AIM: To determine the molecular mechanisms underlying the efficacy of bacillus Calmette-Guérin (BCG) therapy against superficial carcinoma of the urinary bladder, we evaluated the expression of cytotoxic molecules on tumor-infiltrating lymphocytes before and after therapy. METHODS: Immunofluorescence staining allowed the specific detection of Fas, Fas ligand (FasL), and tumor necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL) expression on tumor cells and the respective leukocyte populations in biopsy samples from 6 patients. RESULTS: Significant increases in the infiltration of FasL- and TRAIL-expressing CD4+ T cells and macrophages and FasL-expressing CD8+ T and NK cells were observed after BCG instillation in bladder carcinoma. Moreover, Fas expression was upregulated on tumor cells after BCG instillation. CONCLUSION: The data suggested that the enhanced infiltration of FasL- and/or TRAIL-expressing leukocytes (CD4+ T cells, CD8+ T cells, natural killer cells and macrophages) and the induction of Fas expression on tumor cells may play an important role in the therapeutic effect of BCG instillation.
