Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P15088 (mast cell)
 14,925 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Rab proteins are ras-like low molecular mass GTP-binding proteins, which are postulated to act as specific regulators of membrane trafficking in exocytosis and endocytosis. We have previously shown that synthetic peptides, corresponding to the effector domain of Rab3 proteins, stimulate a complete exocytotic response in mast cells. We have used a PCR-cloning strategy to investigate the presence of mRNA encoding Rab3 in mast cells. RNA based PCR was then performed on mast cell RNA using degenerate oligonucleotide primers based on two conserved sequences among Rab3 proteins. However, no PCR products were obtained, even for proteins known to be expressed in high copy numbers in mast cells (beta-actin and Fc receptor). We have found that the problem resides in the presence of mast cell secretory granule derived heparin, that copurifies with the RNA; heparin has been shown to inhibit the activity of reverse transcriptase and Taq polymerase in PCR. After treating the RNA (obtained from about 500 mast cells) with heparinase, several PCR products of varying size were obtained using primers specific for Rab3 proteins. These products were cloned and sequenced. We have found clones containing sequences that had a 100% homology at the deduced amino acid level to a portion of Rab3B and Rab3D (amino acids 16 to 83).
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PMID:RT-PCR cloning of Rab3 isoforms expressed in peritoneal mast cells. 750 66

In this report we demonstrate that murine bone marrow cells cultured in either interleukin (IL)-3 or mast cell growth factor (MGF, also known as c-kit ligand and stem cell factor) differentially express cytokine genes. Bone marrow cells cultured in IL-3 differentiate and proliferate, taking on a mucosal mast cell-like phenotype. These cells express the IL-4 gene. Bone marrow cells cultured in MGF take on a connective tissue mast cell-like phenotype and possess transcripts for both of the subunits of the IL-12 cytokine. Bone marrow cells cultured in both IL-3 and MGF express the IL-4 gene at lower levels than that seen for the IL-3 culture alone, but do not possess IL-12 gene transcripts. The level of IL-12 subunit transcripts derived from the MGF-derived bone marrow cells was compared to that found in splenocytes and activated macrophages, the only cells in which IL-12 production has been previously documented. Both of the IL-12 subunit transcripts were found, compared to a beta-actin control, to be present within MGF-derived cells in the same if not higher quantities than the splenocyte or macrophage cultures. Mucosal mast cells have been previously implicated in the development of the T helper type 2 (TH2) T cell phenotype via their expression of IL-4. The finding that the MGF-derived connective tissue-like mast cells possess IL-12 transcripts suggests that the development of the TH1 T cell pathway may be positively influenced by this type of mast cell.
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PMID:Preferential expression of interleukin-12 or interleukin-4 by murine bone marrow mast cells derived in mast cell growth factor or interleukin-3. 751 32

We examined the capacity of interleukin (IL)-4 to induce or enhance the expression of certain cytokines in resting and activated cells of the HMC-1 human leukemic mast cell line. The HMC-1 mast cells were cultured with or without recombinant human IL-4 and then activated with the calcium ionophore ionomycin. Stimulation of non-IL-4-treated cells with ionomycin (10 microM) for periods of 30 min to 8 hr induced expression of mRNA encoding IL-3, IL-4 and IL-8 but was without effect on levels of mRNA for tumour necrosis factor (TNF)-alpha or beta-actin. Culture of the cells with IL-4 (100 ng/ml) for 24 hr led to a small increase in resting levels of mRNA for IL-3 and IL-8 but not for IL-4, TNF-alpha or beta-actin. More notably, the IL-4 treatment produced a pronounced elevation of mRNA for IL-3 and IL-8 when the cells were subsequently activated with ionomycin. The IL-4 treatment produced a negligible effect on IL-4 mRNA, and no effect on TNF-alpha or beta-actin mRNA levels in ionomycin-activated cells. Quantitation of cDNA by competitive polymerase chain reaction (PCR) revealed that the IL-4 treatment produced a sixfold increase in ionomycin-induced levels of cellular IL-3 mRNA, a fourfold increase in induced IL-8 mRNA and less than a twofold increase in induced IL-4 mRNA. The IL-4 treatment led to a 15- to 20-fold increase in ionomycin-induced secretion of IL-3 product and a doubling of induced IL-8 product. These effects of IL-4 were not associated with increased mast cell numbers. We conclude that IL-4 alone is a weak activator of IL-3 and IL-8 gene expression in mast cells, but is able to enhance activation signals in stimulated mast cells leading to transcription and secretion of these two cytokines.
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PMID:IL-4 enhances IL-3 and IL-8 gene expression in a human leukemic mast cell line. 775 Oct 24

We have examined the effects of mercuric chloride (HgCl2) on growth and IL-4, IL-8, TNF-alpha and MHC class II gene expression in the HMC-1 human leukemic mast cell line. Proliferation, measured by [3H]thymidine incorporation or production of a formazan product (MTT assay), was substantially inhibited by HgCl2 at concentrations of 10(-6) M and above. Inspection of the DNA by agarose gel electrophoresis from HgCl2-treated cells revealed that it was intact, indicating inhibition of DNA synthesis, but not denaturation. HgCl2 inhibited expression of mRNA for IL-8, TNF-alpha and MHC class II at 4 x 10(-6) M and inhibited expression of IL-4 mRNA at 8 x 10(-6) M and above. At a concentration of 10(-5)M, HgCl2 almost completely blocked mRNA expression for IL-4, IL-8, TNF-alpha and MHC class II, but produced negligible inhibition of expression of mRNA encoding the housekeeping gene beta-actin, thus demonstrating selective toxicity for the cytokine and MHC class II genes studied. Pre-exposure of the cells to human recombinant IL-4 prior to treatment with HgCl2 had no effect on expression levels of any of the genes examined. The effects seen in this study are consistent with previous reports showing immunotoxic effects of HgCl2 on other cell types, therefore, the HMC-1 mast cell line may prove useful in further studies of mast cell cytokine gene expression and the mechanisms involved in cytokine gene toxicity.
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PMID:The effects of mercuric chloride on growth, cytokine and MHC class II gene expression in a human leukemic mast cell line. 856 Apr 97

To define the molecular regulation of mast cell phenotype and function optimized procedures must be available to study mRNA from mast cells freshly isolated from tissues. However, rat peritoneal mast cells (PMC) contain large amounts of the proteoglycan heparin, and unfortunately, this molecule which is a potent inhibitor of reverse transcriptase (RT) and Taq polymerase and thus RT-PCR, copurifies with RNA. Here we describe an optimized protocol for extracting and amplifying RNA from rat PMC. Mast cells were isolated from rat peritoneum and a method modified from that of Chomczynski and Sacchi (1987) was used to extract the RNA. Following the removal of heparin by heparinase digestion, first strand cDNA synthesis was primed with oligo-dT and the resulting cDNA was quantified by rapid paper chromatography. The use of a detection system for the reverse transcription reaction ensured that the production of cDNA had occurred and allowed subsequent PCR testing to be optimal. cDNA thus produced can be used to detect relatively specific (histidine decarboxylase) and non-specific (beta-actin) mast cell products. Our PCR studies have shown a 300-fold increase in sensitivity over RNA processed by other methods.
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PMID:Optimization of the isolation and effective use of mRNA from rat mast cells. 905 Sep 42

A mast cell line, RBL-2H3, was exposed to 835 MHz for 20 minutes, three times per day for 7 days at a power density of 8.1 +/- 3 mW/cm2. From day 4 onwards, it was observed that the rate of DNA synthesis and cell replication increased, that actin distribution and cell morphology became altered, and the amount of beta-hexosaminidase (a marker of granule secretion) released in response to a calcium ionophore was significantly enhanced, in comparison to unexposed cultures. There were no effects seen on levels of cytoskeletal protein synthesis or of beta-actin mRNA. Morphological changes persisted following subculture for at least 7 days in the absence of further exposure. It is hypothesized that effects of exposure to an electromagnetic field at 835 MHz may be mediated via a signal transduction pathway.
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PMID:Effects of exposure to electromagnetic radiation at 835 MHz on growth, morphology and secretory characteristics of a mast cell analogue, RBL-2H3. 931 43

The stem cell factor (SCF)/c-kit ligand/receptor system has been implicated in stem (oval) cell activation following liver injury in the rat. The aim of this study was to determine the role of the SCF/c-kit system in pediatric human liver during acute and chronic liver injury. Tissue was obtained from hepatectomy specimens of patients undergoing liver transplantation for extrahepatic biliary atresia (EHBA) and fulminant hepatic failure (FHF). Specific expression of mRNA for c-kit and beta-actin was measured by ribonuclease protection and by immunohistochemistry to localize c-kit in tissue sections. Expression of c-kit was detected at relatively consistent levels in normal and cirrhotic (EHBA) livers. However, in FHF, c-kit mRNA levels were elevated in 3 of 6 specimens. Immunolocalization highlighted the presence of small numbers of c-kit-positive cells in the portal tracts of normal livers with increased numbers in cirrhotic livers. The highest c-kit staining, however, was observed in FHF, in which, in addition to the cells in the portal tracts, discrete c-kit-positive cells were also found integrated into bile ducts. Colocalization studies demonstrated some of the c-kit-positive cells to be of mast cell, leukocyte, and hematopoietic cell origin. However, there remained a subset that was also negative for these markers. The up-regulation of c-kit receptor expression in diseased livers suggests an involvement of this receptor/ligand system in hepatic repair mechanisms, and we speculate that c-kit-positive cells may represent a hepatic progenitor cell population. The origin and growth/differentiation potential of these c-kit-positive cells is under investigation.
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PMID:Expression of the stem cell factor receptor c-kit in normal and diseased pediatric liver: identification of a human hepatic progenitor cell? 1038 46

Disodium cromoglycate (cromolyn) inhibits mast cell secretion, but its mechanism has not been elucidated. One possibility is the phosphorylation of a 78-kDa mast cell protein, two fragments of which are homologous to moesin, a member of the ezrin, radixin, moesin family. These proteins appear to be involved in signal transduction by regulating functional associations between the cell surface and the cytoskeleton. Moesin cDNA was cloned from rat basophil leukemia cells, which are similar to mucosal mast cells, and polyclonal antiserum was prepared against recombinant moesin expressed in Escherichia coli. Moesin phosphorylated in mast cells treated with cromolyn shifted from the soluble to the precipitable fraction and associated with Sepharose-linked beta-actin. Recombinant moesin also associated with Sepharose-linked beta-actin, and so did purified RBL moesin, but only if the latter was first denatured. Moesin thus appears to have actin binding sites that are not exposed under normal conditions but may become available by in vivo phosphorylation or by denaturation. Immunocytochemistry using confocal microscopy showed moesin to be primarily localized on the inner aspect of the plasma membrane and around secretory granules. Double immunocytochemistry for moesin and actin colocalized them in most areas. Ultracryoimmunoelectron microscopy to preserve the antigenicity of moesin identified the protein close to the plasma and secretory granule membranes. Cromolyn appeared to induce clustering of moesin around secretory granules. It is hypothesized that conformational changes of moesin, regulated by phosphorylation/dephosphorylation, may lead to positional rearrangements with respect to the membrane/cytoskeleton that could possibly regulate mast cell secretion.
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PMID:Cloning and cellular localization of the rat mast cell 78-kDa protein phosphorylated in response to the mast cell "stabilizer" cromolyn. 1094 28

Lactoferrin (LF), a glycogen of the transferrin family with anti-bacterial and immunomodulatory properties, is expressed in various secretions and tissues. Cutaneous LF serves as a mast cell stabilising compound, modulates T cell activity and is found during IgE-mediated late phase reactions at allergen challenged sites. Culicoides hypersensitivity (CHS) in horses is a common IgE-mediated allergic dermatitis, characterised by an early and late phase cutaneous reaction upon allergen challenge. The aim of the study presented here was to examine whether LF mRNA expression in skin biopsies from horses affected by CHS prior to and 4h following intradermal challenge with a commercial C. nubeculosus extract is modified in comparison to skin biopsies from non-affected horses. In order to obtain reliable data, real time PCR was performed and genes of interest were normalized using three different housekeeping genes, beta-actin, GAPDH, beta-2-microglobulin. In comparison to non-affected horses, higher variation in LF mRNA levels both prior to and post-intradermal challenge with C. nubeculosus extract was seen in horses affected by CHS. However, the statistical analysis demonstrated that LF mRNA expression was not significantly different between CHS affected and non-affected horses prior to intradermal challenge with C. nubeculosus extract. Intradermal injection of C. nubeculosus extract did not result in local upregulation of LF mRNA at 4h post-injection. LF mRNA expression was therefore not significantly different pre- or post-intradermal challenge with C. nubeculosus extract in either group. Our data indicate that clinically normal skin of horses affected by CHS is not characterized by modified maintenance levels of LF mRNA. In contrast to human skin allergen challenged sites, LF mRNA levels in horses affected by CHS are not significantly different to that of control sites at 4h post-injection of C. nubeculosus extract.
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PMID:Lactoferrin, a glycoprotein with immunomodulatory and mast cell stabilising properties, in skin of horses suffering from Culicoides hypersensitivity. 1722 35

It is now established that non-contractile cells with thin filopodia, also called vascular interstitial cells (VICs), are constitutively present in the media of many, if not all, blood vessels. The aim of this study was to determine the type of cell lineage to which arterial VICs belong using immunocytochemical, and real-time and reverse transcription PCR (RT-PCR). Using RT-PCR, we compared gene expression profiles of single VICs and smooth muscle cells (SMCs) freshly dispersed from rat middle cerebral artery. Both VICs and SMCs expressed the SMC marker, smooth muscle myosin heavy chain (SM-MHC), but did not express fibroblast, pericyte, neuronal, mast cell, endothelial or stem cell markers. Freshly isolated VICs also did not express c-kit, which is the marker for interstitial cells of Cajal in the gastrointestinal tract. Immunocytochemical labelling of contractile proteins showed that VICs and SMCs expressed SM-MHC similarly to the same degree, but VICs in contrast to SMCs had decreased expression of alpha-SM-actin and very low or no expression of calponin. Real-time RT-PCR was consistent with immunocytochemical experiments and showed that VICs had four times lower gene expression of calponin comparing to SMCs, which may explain VICs' inability to contract. VICs had greater expression than SMCs of structural proteins such as non-muscular beta-actin and desmin. The results obtained suggest that VICs represent a subtype of SMCs and may originate from the same precursor as SMCs, but later develop filopodia and a non-contractile cell phenotype.
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PMID:Interstitial cells from rat middle cerebral artery belong to smooth muscle cell type. 1917 86


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