Project description:The aim of this study was to investigate microRNA expression pattern and its functional relevance on the commitment toward mucosal differentiation and on IgE-mediated activation of mast cells. To identify microRNA genes the expression of which change during the differentiation and activation of murine primary mast cells in vitro, the putative committed progenitors (c-kit+ cells isolated on day 6 from differentiating cultures), immature mast cells (BMMC), mucosal-type mast cells (MMC), and IgE-activated mast cells were compared by Agilent microRNA array. RNA was isolated by miRNeasy (Qiagen) from: 1) c-kit+ cells, isolated from differentiating cultures (in the presence of IL3 and SCF) derived from the bone marrow using MACS column purification, 2) immature BMMCs obtained by cultivation of bone marrow cells in the presence of IL3 and SCF for 4 weeks, 3) mucosal-type mast cells by additional differentiation of immature BMMCs for 5 days by supplementation of IL9 and TGFbeta, and 4) activated mast cells by presensitization with anti-DNP IgE followed by IgE-crosslinking by DNP-antigen challenge for 2 hours. Agilent microRNA microarray was run on these experimental groups. Four biological replicates were included in every experimental group.
Project description:The aim of this study was to investigate microRNA expression pattern and its functional relevance on the commitment toward mucosal differentiation and on IgE-mediated activation of mast cells. To identify microRNA genes the expression of which change during the differentiation and activation of murine primary mast cells in vitro, the putative committed progenitors (c-kit+ cells isolated on day 6 from differentiating cultures), immature mast cells (BMMC), mucosal-type mast cells (MMC), and IgE-activated mast cells were compared by Agilent microRNA array.
Project description:Mast cells, activated by antigen via the high affinity receptor for IgE (FcεRI), release an array of pro-inflammatory mediators that contribute to allergic disorders such as asthma and anaphylaxis. The KIT ligand, stem cell factor (SCF), is critical for mast cell expansion, differentiation and survival, and, under acute conditions, enhances mast cell activation. However, extended SCF exposure in vivo conversely protects against fatal antigen-mediated anaphylaxis. In investigating this dichotomy, we identified a novel mode of regulation of the mast cell activation phenotype through SCF-mediated programming. We found that mouse bone marrow-derived mast cells chronically exposed to SCF displayed a marked attenuation of FcεRI-mediated degranulation and cytokine production. The hypo-responsive phenotype was not a consequence of altered signals regulating calcium flux or protein kinase C, but of ineffective cytoskeletal reorganization, with evidence implicating a down-regulation of expression of the Src kinase Hck. Collectively, these findings demonstrate a major role for SCF in the homeostatic control of mast cell activation with potential relevance to mast cell-driven disease and the development of novel approaches for the treatment of allergic disorders. Mouse bone marrow-derived mast cells were treated with IL3, IL3+IL33, or IL3+SCF. Six replicates each.
Project description:Intestinal mucosal mast cells are critically involved in the development of food-induced allergic disorders. However, factors that induce differentiation of mucosal mast cells in the intestinal mucosa are largely unknown. To identify factors involved in mucosal mast cell differentiation, we compared the gene expression profiles between mucosal mast cells isolated from the small intestine and bone marrow-derived mast cells cultured in the presence of TGF-β or Notch ligand. Mucosal mast cells were isolated from the small intestine of naïve BALB/c mice by flow cytometry. Bone marrow-derived mast cells (BMMCs) were generated by culturing BALB/c bone marrow cells with murine interleukin-3 and stem cell factor for 3-4 weeks, and then cells were cultured for 6 days in the presence or absence of TGF-β or Delta-like 1 (Dll1), which is a Notch ligand. Total RNAs extracted from these cells were processed and hybridized to Affymetrix GeneChips.
Project description:Intestinal mucosal mast cells are critically involved in the development of food-induced allergic disorders. However, factors that induce differentiation of mucosal mast cells in the intestinal mucosa are largely unknown. To identify factors involved in mucosal mast cell differentiation, we compared the gene expression profiles between mucosal mast cells isolated from the small intestine and bone marrow-derived mast cells cultured in the presence of TGF-β or Notch ligand.
Project description:We performed large-scale comparative microarrays of bone marrow -derived mast cells and basophils at rest, upon an adaptive-type action (IgE-crosslinking) or upon innate-type activation (IL-33-activation).
Project description:We performed large-scale comparative microarrays of bone marrow -derived mast cells and basophils at rest, upon an adaptive-type action (IgE-crosslinking) or upon innate-type activation (IL-33-activation).
Project description:Experimental IgE-mediated food allergy depends on intestinal anaphylaxis driven by interleukin (IL)-9. However, the primary cellular source of IL-9 and the mechanisms underlying the susceptibility to food-induced intestinal anaphylaxis remain unclear. Herein, we have reported the identification of multifunctional IL-9-producing mucosal mast cells (MMC9s) that can secrete prodigious amounts of IL-9 and IL-13 in response to IL-33, and mast cell protease-1 (MCPt-1) in response to antigen and IgE complex crosslinking, respectively. Repeated intragastric antigen challenge induced MMC9 development that required T cells, IL-4, and STAT6 transcription factor, but not IL-9 signals. Mice ablated of MMC9 induction failed to develop intestinal mastocytosis, which resulted in decreased food allergy symptoms that could be restored by adoptively transferred MMC9s. Finally, atopic patients that developed food allergy displayed increased intestinal expression of Il9 and MC-specific transcripts. Thus, the induction of MMC9s is a pivotal step to acquire the susceptibility to IgE-mediated food allergy. dUTP mRNA-Seq profiles of indicated hematopoietic cell lineages were generated on Illumina HiSeq2500. Hematopoietic cells were isolated from Balb/C mice that developed food allergy and bone marrow-derived mast cells were generated from naïve Balb/C mice
Project description:MicroRNA 155 (miR-155) has been shown to regulate the gene expression of important players of physiological and pathological processes, like hematopoietic lineage differentiation, immunity and inflammation, viral infections, cancer and cardiovascular diseases, among others. Degranulation is an event in which mast cells, upon activation of the FceRI, release their granule content rich in vasoactive amines, proteases and TNFa. Additionally activation of the receptor promotes de novo synthesis of cytokines, chemokines and growth factors. Analysis of bone marrow derived mast cells (BMMC) deficient in miR-155 showed a significant increase in FceRI mediated degranulation and in the release of cytokines like TNFa, IL-6 and IL-13. In addition miR 155-/- mice presented higher anaphylaxis reactions compared to WT mice. Gene expression analysis of BMMC was performed in order to identify intermediaries of FceRI mediated degranulation under the control of miR-155. The results indicate that miR-155 regulates negatively the expression of the regulatory subunits of the kinase PI3Kgamma, Pik3r5 (p101) and Pik3r6 (p84, p87PIKAP), involved in Ca+ influx and degranulation. Total RNA from 3 independent cultures of WT and miR-155-/- BMMC treated with anti-DNP IgE and 20 ng/ml DNP-HSA for 1hr were used to performed gene expression analysis using the Affymetrix GenechipM-BM-. Mouse Gene 1.0 ST
Project description:The zinc finger transcription factor GATA1 plays an essential role for differentiation in several hematopoietic cell lineages including erythroid cells, megakaryocytes and eosinophils. Although some studies demonstrated that GATA1 is also required for mast cell differentiation, the effect of complete ablation of GATA1 in mast cell differentiation has not been examined. Here, by using tamoxifen-inducible conditional Gata1 knockout mice, we show that the role of GATA1 in mast cell differentiation is less than previously anticipated in adult mice. Although systemic administration of tamoxifen resulted in complete ablation of GATA1 protein in bone marrow and spleen, cell number and distribution of peripheral tissue mast cells in Gata1-null mice were comparable to those in wild type mice. Bone marrow cells derived from Gata1-null mice differentiated into mast cells that express both c-Kit and IgE receptor M-NM-1 subunit. Finally, we show a line of evidence that GATA1 and GATA2 cooperatively regulate the expression of several mast cell-specific genes by chromatin immunoprecipitation assays and quantitative RT-PCR analyses. These results indicate that GATA1 is dispensable for differentiation and maintenance of mast cells in postnatal hematopoiesis and the loss of GATA1 function is likely compensated by GATA2. Murine bone marrow-derived mast cells from C57BL/6 mice were transfected with of control or GATA1 siRNA (200 pmol). Two samples were analyzed. Sample1 (ctrsi-mix) is prepared from cells transfected with control siRNA. Sample2 (G1si-mix) is prepared from cells transfected with GATA1 siRNA. For each siRNA treatment, two replicate samples prepared from different animals were pooled and used for the analysis.