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Query: UNIPROT:P15088 (mast cell)
 14,925 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Many mast cells are present in the tumor tissues of neurofibromatosis 1. We investigated the mechanism of the mast cell increase. Since the stem cell factor (SCF) induces development of mast cells and since the receptor of SCF is encoded by the c-kit gene, we examined the expression of SCF mRNA and c-kit mRNA in neurofibroma tissues. In situ hybridization demonstrated strong expression of c-kit messenger RNA in mast cells in the neurofibroma, but the expression of SCF mRNA was not demonstrable by in situ hybridization in either neurofibroma tissues or control normal skin tissues. When RNA extracted from neurofibroma tissues or normal skin tissues was reverse transcribed and then amplified by the polymerase chain reaction, the amount of SCF cDNA was greater in neurofibroma tissues than in normal skin tissues. The results suggest that SCF and the c-kit receptor are associated with the increase of mast cells in neurofibroma tissues.
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PMID:Possible involvement of c-kit receptor and its ligand in increase of mast cells in neurofibroma tissues. 769 36

The recently cloned interleukin 13 (IL-13) shares most investigated biological activities on B lymphocytes and monocytes with IL-4. In this study we investigated the potential role of IL-13 in regulating human mast cell activities. The effects of IL-13 on the expression of an immediate-early response gene (c-fos), proliferation, expression of mast cell-associated cell surface antigen (CD54 and Kit), and in vitro differentiation of human mast cells, were investigated. We compared the effect of IL-13 with that of IL-4. Both IL-13 and IL-4 induced expression of c-fos in cells from the human mast cell line HMC-1. This indicates that mast cells express functional receptors for IL-13. IL-13 and IL-4 decreased the proliferation rate of HMC-1 cells. However, IL-13 was less potent than IL-4. Human mast cells constitutively express the adhesion molecule ICAM-1 (CD54) and the receptor for stem cell factor (Kit) (CD117). The expression of CD54 was increased after treatment with IL-13 or IL-4, whereas the expression of Kit was decreased. Also in this action IL-4 was more potent than IL-13. By culturing mononuclear cells from cord blood in the presence of stem cell factor there is a differentiation of tryptase-positive mast cells in the cultures. This process was inhibited when IL-4 was present. In contrast, IL-13 did not affect the expression of tryptase during differentiation of stem cell factor dependent cord blood-derived mast cells. Taken together, these findings indicate that IL-13 has regulatory effects on human mast cells. The effect overlaps with but is also different from that of IL-4.
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PMID:Effects of interleukin (IL)-13 on immediate-early response gene expression, phenotype and differentiation of human mast cells. Comparison with IL-4. 770 21

Mast cell neutral proteases are the most precise markers of heterogeneity among human mast cells. Two types of human mast cells have been recognized. MCTC cells contain tryptase together with chymase, cathepsin-G like protease, and mast cell carboxypeptidase; MCT cells contain tryptase, but lack the other neutral proteases present in MCTC cells. All mast cells develop from hemopoietic stem cells. In vitro procedures for studying mast cell growth have been developed, using the major human mast cell growth factor, stem cell factor (SCF, also called Kit-ligand). Cultures of hemopoietic progenitor cells in the presence of SCF alone result in selective differentiation to mast cells. The same progenitor cells can be induced to differentiate into other lineages when SCF is used with various lineage-specific colony-stimulating factors such as erythropoietin for erythrocytes. Mast cell development from hematopoietic progenitors may represent a "default pathway," occurring optimally in a permissive microenvironment such as skin, bowel, and lung. The presence or absence of certain cytokines in blood and bone marrow may create a non-permissive environment, thus the absence of granulated mast cells in such locations.
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PMID:Human mast cell heterogeneity. 772 Oct 78

A number of new observations have added to our understanding of mast cell biology and the relevance of this cell to the genesis of asthma. The purpose of this review has been to highlight this new information and to refer the reader to extensive reviews where previously documented and well-known data are available. Of particular current interest is the knowledge that mast cell growth and differentiation is regulated by a specific molecule, stem cell factor, which interacts with a receptor on the surface of the mast cell (a tyrosine kinase) and that mast cell phenotype may be modulated by exposure to stem cell factor as well as to a host of inflammatory cytokines. In addition to the ability to release vasoactive/spasmogenic mediators characterized by histamine, the slow-reacting substance of anaphylaxis (sulfidopeptide leukotrienes), platelet-activating factor, and adenosine, the mast cell can release a unique family of enzymes and generate a cassette of cytokines with critically important pro-inflammatory potential. The enzymes that are unique to the mast cell can potentiate a number of inflammatory events central to asthma, including fibroblast activation, mucus secretion, smooth muscle contraction, and neuropeptide degradation, while the cytokines may directly influence the influx, persistence, and activity of inflammatory cells, particularly eosinophilis and basophils, through the ability of the cytokines to modulate endothelial expression of leukocyte adhesion receptors and to prevent target cell apoptosis.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Mast cells and airway inflammation in asthma. 795 90

To determine the fate of Fc epsilon RI+ cells on fibroblasts in vitro, human bone marrow derived CD34+ cells were cultured in the presence of recombinant human interleukin 3 and recombinant human hematopoietic stem cell factor for 3 weeks, and Fc epsilon RI+ cells were purified by immunomagnetic selection. This enriched Fc epsilon RI+ cell population consisted of 92-94% basophils and 3-5% mast cells as determined by morphologic, immunohistochemical, and ultrastructural criteria. The Fc epsilon RI+ cells were then cocultured with 3T3 fibroblasts. Basophils decreased markedly by 1 week and were absent from cocultures by 2-3 weeks, while the mast cell numbers on the fibroblast monolayers remained constant. Ultrastructural examination of cocultures at 2 days demonstrated phagocytosis of basophils by fibroblasts. By 1 week, phagocytosed basophil membranes and granules gave fibroblasts the superficial appearance of mast cells by toluidine blue staining. Mast cells surviving in cocultures could be distinguished from granule-containing fibroblasts by IgE surface labeling and by ultrastructural demonstration of tryptase-positive granules. Thus, while mast cells remain viable in coculture with 3T3 fibroblasts, basophils do not survive and are internalized and degraded by the fibroblast monolayer.
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PMID:Fibroblasts determine the fate of Fc epsilon RI+ cell populations in vitro by selectively supporting the viability of mast cells while internalizing and degrading basophils. 798 8

The basic understanding of mast cell ontogeny and function has been fundamentally changed in recent years with observations that the cells produce and respond to a broad range of cytokines. These rapidly accruing data and their potential significance were discussed at the recent symposium "Mast Cells in the Cytokine Network", and the overview lectures of most speakers are summarized in this special journal issue. In the present introductory manuscript, the organizers of the meeting discuss data fundamental to an understanding of the topic and highlight aspects of special interest. They consider mast cells to be defined most reliably by their unique ultrastructure since the cells are highly heterogeneous in dependence of the species studied, their tissue location, their stage of development and probably also in relation to cytokines. Most other characteristics of mast cells are shared with diverse other cell types. Murine mast cell development is induced by several cytokines. These factors are mostly ineffective in human cells except for stem cell factor which causes mast cell development from CD34+/c-kit+ progenitors. There is however recent evidence that fibroblasts and keratinocytes produce additional growth factors for human mast cells. Regarding cytokine secretion, most molecules known so far are produced by both murine and human mast cells. The cells furthermore bear receptors for several cytokines, enabling them to respond in an autocrine and paracrine fashion. Mast cells may thus function within a complex cytokine network, affecting physiological as well as immunological and inflammatory processes.
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PMID:Mast cells in the cytokine network: the what, where from and what for. 852 93

The regulation of tissue mast cell number depends both on the rate of production of mast cell precursors from bone marrow and the length of survival of mature mast cells within tissues. Mast cells develop from bone marrow under the influence of both interleukin-3 (IL-3) and the c-kit ligand, also known as stem cell factor (SCF). In humans, the mast cell precursor is CD34+, FcERI-. Mast cell precursors with time become less responsive to IL-3 and more responsive to SCF. Mast cell proliferation directed by SCF is enhanced by other cytokines including both IL-4 and IL-10. Once mast cell precursors target to tissues, their survival may largely be dependent upon the local production of SCF. Withdrawal of IL-3 or SCF results in mast cell apoptosis; SCF rescues mast cells following IL-3 withdrawal. TGF-beta prevents this SCF rescue. Engagement of extracellular matrix by integrin receptors may also effect mast cell numbers. Thus, in the final analysis, mast cell numbers, while relatively constant in the normal state, may be up-regulated by altering the rate of their production centrally or length of survival in the periphery.
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PMID:Mast cell ontogeny and apoptosis. 852 94

Two mutations of c-kit receptor tyrosine kinase (KIT), valine-559 to glycine (G559) and aspartic acid-814 to valine (V814), resulted in its constitutive activation. To examine the transforming and differentiation-inducing potential of the mutant KIT, we used the murine interleukin-3-dependent IC-2 mast cell line as a transfectant. The IC-2 cells contained few basophilic granules and did not express KIT on the surface. The KITG559 or KITV814 gene was introduced into IC-2 cells using a retroviral vector. KITG559 and KITV814 expressed in IC-2 cells were constitutively phosphorylated on tyrosine and demonstrated kinase activity in the absence of stem cell factor, which is a ligand for KIT. IC-2 cells expressing either KITG559 or KITV814 (IC-2G559 or IC-2V814 cells) showed factor-independent growth in suspension culture and produced tumors in nude athymic mice. In addition, IC-2G559 and IC-2V814 cells showed a more mature phenotype compared with the phenotype of the original IC-2 cells, especially after transplantation into nude mice. The number of basophilic granules and the content of histamine increased remarkably. KITG559 and KITV814 also influenced the transcriptional phenotype of mouse mast cell proteases (MMCP) in IC-2 cells. The expression of MMCP-2, MMCP-4, and MMCP-6 was much greater in IC-2G559 and IC-2V814 cells than in the original IC-2 cells. The results indicated that constitutively activated KIT had not only oncogenic activity but also differentiation-inducing activity in mast cells.
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PMID:Transforming and differentiation-inducing potential of constitutively activated c-kit mutant genes in the IC-2 murine interleukin-3-dependent mast cell line. 854 6

A peculiar point mutation results in constitutive activation of c-kit receptor tyrosine kinase (KIT) in three different tumor mast cell lines; ie, the HMC-1, P-815, and RBL-2H3. Because constitutive activation of KIT was also observed in the FMA3 mouse mastocytoma cell line, we investigated the molecular mechanism. Sequencing of the whole coding region of the c-kit showed that the point mutation found in HMC-1, P-815, and RBL-2H3 cells was absent in FMA3 cells and that the c-kit cDNA of FMA3 cells carried an in-frame deletion of 21 base pairs (bp) encoding Thr-Gln-Leu-Pro-Tyr-Asp-His at codons 573 to 579 at the juxtamembrane domain. The FMA3-type c-kit cDNA with 21 bp deletion was introduced into the IC-2 cell line, which was derived from murine cultured mast cells. IC-2 cells were dependent on interleukin (IL)-3 and did not express KIT on the surface. In IC-2 cells introduced with the FMA3-type c-kit cDNA, KIT was constitutively phosphorylated on tyrosines and activated. Moreover, the FMA3-type KIT was dimerized without the stimulation by stem cell factor (SCF), a ligand for KIT. The spontaneously dimerized FMA3-type KIT without SCF binding was not internalized even after the activation. IC-2 cells expressing the FMA3-type KIT grew in suspension culture without IL-3 and SCF and became leukemic in nude athymic mice. The deletion of seven amino acids at the juxtamembrane domain appeared to be a new activating mutation of KIT that might be involved in neoplastic growth of mast cells.
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PMID:Constitutive activation of c-kit in FMA3 murine mastocytoma cells caused by deletion of seven amino acids at the juxtamembrane domain. 854 52

The phenotypic and biologic properties of malignant cells in a case of aggressive mastocytosis with multi-organ involvement, circulating mast cell precursors and absence of skin infiltrates were analyzed. Circulating mast cell precursors were detected by immunostaining using antibodies against mast cell tryptase as well as by electron microscopy. These progenitors were tryptase+/chymase- (MCT) and accounted for 10 to 20% of nucleated mononuclear blood cells (MNC). A subset of them contained metachromatic granules. As assessed by combined toluidine blue/immunofluorescence staining, the granulated mast cell precursors were found to express CD9 (P24), CD33 (gp67) and CD44 (Pgp-1), but not basophil-related markers (CD11b (C3biR), CDw17 (lactosylceramide), CD123 (il-3R alpha))or monocyte-related antigens (CD14, CD15). Expression of the mast cell growth factor (MGF) receptor, c-kit(CD117), was also demonstrable, whereas the skin mast cell marker C5aR (CD88) could not be detected on mast cell precursors. The ligand of c-kit, recombinant human (rh) stem cell factor (SCF = MGF), induced histamine release from circulating mast cell progenitors, whereas rhC5a, a potent skin mast cell-/basophil-agonist, was ineffective over the dose-range (10(-9) to 10(-7(M)) tested. Analysis of mast cell antigens in malignant mastocytosis or mast cell leukemias may be helpful to establish a diagnosis and to determine the phenotype of the clone.
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PMID:A case of malignant mastocytosis with circulating mast cell precursors: biologic and phenotypic characterization of the malignant clone. 855 22


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