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)

The reverse transcriptase polymerase chain reaction (RT-PCR) procedure is markedly inhibited in specimens of blood that contain commercial heparin as an anticoagulant or in cell preparations containing rat or mouse peritoneal mast cells. However, it was not known whether the levels of endogenous, mast cell-associated heparin that are present in some mammalian tissues are sufficient to interfere with the use of RT-PCR in these settings. We show that RT-PCR detects little or no mRNA transcripts for either mast cell-associated products, such as mouse mast cell-associated protease-2 or -4 (MMCP-2 or MMCP-4) or mast cell carboxypeptidase A, or for mast cell-nonspecific products, such as glyceraldehyde 3-phosphate dehydrogenase, in routinely prepared specimens of cells or tissues that include populations of heparin-containing mast cells. However, signals for mast cell-associated or mast cell-nonspecific transcripts can be readily detected in such specimens if they are treated with heparinase before RT-PCR. RT-PCR after heparinase treatment appears to represent an extremely sensitive method for detecting mast cell-associated transcripts in tissue specimens, permitting the identification of transcripts for mast cell-specific proteases in the skin of genetically mast cell-deficient WBB6F1-W/WV mice, a tissue that contains few or no mast cells according to histological analysis.
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PMID:Detection of mouse mast cell-associated protease mRNA. Heparinase treatment greatly improves RT-PCR of tissues containing mast cell heparin. 785 46

The present report describes a novel function of mast cells that consists of a B cell growth activity. The B cell response occurred without any stimulation or preactivation of mast cells. A small number of mast cells was required, since mast cell/B cell ratios as low as 1/100 to 1/10,000 lead to effective B cell activation. Mast cell-dependent B cell activation resulted, within 48 h of incubation, in blast formation, proliferation, and IgM production. Both low and high density B cells were responsive to mast cells. Supernatants from unstimulated mast cells could also activate B cells, suggesting that a B cell-stimulating activity (MC-BSA) is mediated by a soluble factor(s). The addition of anti-IL-4 or anti-IL-6 mAbs or even proteases to the mast cell-derived supernatants did not alter B cell activation. However, treatment of mast cells with mitomycin C or actinomycin D, or paraformaldehyde fixation totally abrogated MC-BSA. Fractionation of mast cell supernatant by gel filtration chromatography resulted in four peaks, ranging from > 200 to 15 kDa, all of which were biologically active on B cells. Because mast cells are known to continuously release proteoglycans, MC-BSA was subjected to chondroitinase and heparinase treatment, but no significant inhibition of B cell activation was obtained. This direct T cell-independent stimulatory effect of mast cells on B cells could account for a mechanism by which plasma cells are continuously produced in lymphoid organs and particularly in bone marrow.
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PMID:Mouse bone marrow-derived mast cells and mast cell lines constitutively produce B cell growth and differentiation activities. 875 61

We used cationized colloidal gold in order to investigate the distribution of anionic sites in different secretory granules of rat and mouse mast cells. The localization of the anionic sites was performed by post-embedding labeling of thin sections of rat peritoneal cells or mouse skin tissue, fixed in Karnovsky's fixative and OsO4, and embedded in Araldite or LR white, respectively. In all cases anionic sites were demonstrated with a high density variation depending on cell type. In all mast cell secretory granules we have observed the highest density (ca. 500-900 gold particles/microns2), while in other peritoneal cell granules it was about 10 times less (ca. 40-80 gold particles/microns2). Pretreatment of the LR white sections with heparinase I and III resulted in a reduction of 97% and 72%, respectively, in the binding of the gold particles to the granules, indicating that the majority of the gold binding reactivity is due to heparin. Correlation of section profile area with labeling density revealed that the smaller granules were significantly more labeled when compared to the larger profiles. On the basis of these observations it seems that a post-translational change (mainly sulfation of heparin) of secretory content influences the granule anionic charge and thus may affect the intragranule buffer capacity.
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PMID:An histochemical approach to characterization of anionic constituents in mast cell secretory granules. 877 31

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

Contact activation occurs when plasma comes in contact with negatively charged manmade surfaces but no substance that initiates contact activation in vivo has been identified. We have isolated a mast cell heparin proteoglycan (MC-HepPG) from a Furth mouse mastocytoma-derived cell line that is analogous to human tissue-type mast cell HepPG. This material and other glycosaminoglycans (GAGs) were tested for their ability to accelerate the reciprocal activation of factor XII and prekallikrein and the autoactivation of factor XII. Quantitative analysis showed the MC-HepPG to be as active as dextran sulfate on a weight basis; hog intestine heparin, dermatan sulfate, keratan polysulfate and chondroitin sulfate C were less active, other sulfated polysaccharides were essentially inactive. Incubation of MC-HepPG in 1:4 diluted plasma resulted in complete cleavage of high molecular weight kininogen in a factor XII-dependent reaction. All of the MC-HepPG dependent reactions described above were inhibited by preincubation of MC-HepPG with heparinase I and II but not by pretreatment with heparitinase, chondroitinase ABC or the serine protease inhibitor aPMSF thus indicating that heparin proteoglycan is indeed acting as an initiating 'surface'. We analysed the proteoglycan preparation by HPLC gel filtration. Fractions spanning a molecular weight range of > 400000-8000 were active initiators. Comparison of the chromatograms obtained before and after cleavage of GAG side chains from the protein core suggested that dissociated GAGs in the MW range 69000-17000 are the most active species rather than the complete proteoglycan. MC-HepPG GAGs therefore represent a physiologic macromolecule with activity comparable to non-physiological surfaces in a purified system and with the capability to induce activation of the contact system in diluted plasma. Its ability to promote kinin generation links cellular and humoral inflammatory responses in the perivasculature and provides a possible explanation for the elevated kinin levels observed after allergen exposure.
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PMID:Mast cell derived heparin activates the contact system: a link to kinin generation in allergic reactions. 920 86

Mast cell proteases in the tongue and jejunum of Mongolian gerbils (Meriones unguiculatus) were examined by enzyme-histochemical methods. Both trypsin-like (tryptase) and chymotrypsin-like (chymase) protease activities were demonstrated in mast cells in the tongue of fresh cryosections. When frozen sections of the tongue were post-fixed in various fixatives, those fixed in Carnoy's fluid showed strongest enzyme activities. Tryptase and chymase activities in paraffin sections of both tissues were well preserved when tissues were fixed in Carnoy's fluid at 4 degrees C for 15 min. However, enzyme activities in both tissues, especially in the tongue, were drastically reduced by longer fixation time and higher temperature. When Carnoy-fixed (4 degrees C for 15 min) paraffin sections were treated with heparinase I or chondroitinase ABC before enzyme-histochemical stainings for proteases, tryptase activities were lost entirely in the tongue and mostly in the jejunum by heparinase I digestion, and slightly in both organs by chondroitinase ABC digestion. In contrast, chymase activities at both sites were not influenced by these pretreatments. These results show that although mast cells in the tongue as well as in the jejunum of Mongolian gerbils contain both tryptase and chymase activities, their stability to fixations is variable among organs so that tissue fixation conditions are crucial for the preservation. At least some part of the stability of mast cell proteases is dependent on the proteoglycans present in mast cell granules.
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PMID:Reappraisal of the expression of mast cell proteases of Mongolian gerbils (Meriones unguiculatus). 974 May 13

The addition of rat mast cell granules to confluent bovine pulmonary artery endothelial cell monolayers resulted in the formation of numerous lacunae in the cultures. Several lines of evidence identified heparin proteoglycan as the component of the granule matrix responsible for the effect: presence of the activity in the proteoglycan fraction after chromatography of granule extracts, inhibition of granule activity by digestion with heparinase I, the failure of proteolysis of the proteoglycan fraction with proteinase K to significantly diminish its activity, and the failure of chymase and carboxypeptidase inhibitors to inhibit granule activity. The onset of hole formation was delayed for several hours after granule addition to the culture, and maximal hole formation occurred between 8 and 16 hours and was sustained as long as 24 hours. The lacunae formed by the separation of motile endothelial cells within the monolayer and was not attributable to cell contractile activity or cell loss. Time-lapse video recording showed that the holes were dynamic, individual holes expanding and regressing over a period of hours. Formation of lacunae occurred on gelatin and fibronectin surfaces alike. The presence of active chymase in the granules prevented the action of the proteoglycan. Heparin glycosaminoglycan as distinct from the proteoglycan did not similarly affect the endothelial monolayers but did block the action of granules added subsequently, indicating the likelihood of a heparin-reactive receptor or binding site.
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PMID:Mast cell granule heparin proteoglycan induces lacunae in confluent endothelial cell monolayers. 1032 11

Snake envenomation employs three well integrated strategies: prey immobilization via hypotension, prey immobilization via paralysis, and prey digestion. Purines (adenosine, guanosine and inosine) evidently play a central role in the envenomation strategies of most advanced snakes. Purines constitute the perfect multifunctional toxins, participating simultaneously in all three envenomation strategies. Because they are endogenous regulatory compounds in all vertebrates, it is impossible for any prey organism to develop resistance to them. Purine generation from endogenous precursors in the prey explains the presence of many hitherto unexplained enzyme activities in snake venoms: 5'-nucleotidase, endonucleases (including ribonuclease), phosphodiesterase, ATPase, ADPase, phosphomonoesterase, and NADase. Phospholipases A(2), cytotoxins, myotoxins, and heparinase also participate in purine liberation, in addition to their better known functions. Adenosine contributes to prey immobilization by activation of neuronal adenosine A(1) receptors, suppressing acetylcholine release from motor neurons and excitatory neurotransmitters from central sites. It also exacerbates venom-induced hypotension by activating A(2) receptors in the vasculature. Adenosine and inosine both activate mast cell A(3) receptors, liberating vasoactive substances and increasing vascular permeability. Guanosine probably contributes to hypotension, by augmenting vascular endothelial cGMP levels via an unknown mechanism. Novel functions are suggested for toxins that act upon blood coagulation factors, including nitric oxide production, using the prey's carboxypeptidases. Leucine aminopeptidase may link venom hemorrhagic metalloproteases and endogenous chymotrypsin-like proteases with venom L-amino acid oxidase (LAO), accelerating the latter. The primary function of LAO is probably to promote prey hypotension by activating soluble guanylate cyclase in the presence of superoxide dismutase. LAO's apoptotic activity, too slow to be relevant to prey capture, is undoubtedly secondary and probably serves principally a digestive function. It is concluded that the principal function of L-type Ca(2+) channel antagonists and muscarinic toxins, in Dendroaspis venoms, and acetylcholinesterase in other elapid venoms, is to promote hypotension. Venom dipeptidyl peptidase IV-like enzymes probably also contribute to hypotension by destroying vasoconstrictive peptides such as Peptide YY, neuropeptide Y and substance P. Purines apparently bind to other toxins which then serve as molecular chaperones to deposit the bound purines at specific subsets of purine receptors. The assignment of pharmacological activities such as transient neurotransmitter suppression, histamine release and antinociception, to a variety of proteinaceous toxins, is probably erroneous. Such effects are probably due instead to purines bound to these toxins, and/or to free venom purines.
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PMID:Ophidian envenomation strategies and the role of purines. 1173 31

Imatinib mesylate (Gleevec) inhibits the BCR-ABL tyrosine kinase in chronic granulocytic leukemia. Previous studies have demonstrated that imatinib mesylate also inhibits the survival and functions of normal mast cells by interfering with the receptor tyrosine kinase for stem cell factor (SCF), c-kit, which is expressed by mast cells. Because mast cells extensively surround many types of cancer and contain powerful anticoagulants such as heparin, we investigated the effects of imatinib mesylate on blood clotting and tumor growth within subcutaneous implants of a mammary adenocarcinoma cell line (4T1) in BALB/c mice. After 5 days of oral treatment with 10 mg/kg of the drug, the average mass of the tumors in treated mice (198 +/- 42 mg, n = 5) was significantly (p < 0.05) greater than the average mass of the tumors from untreated (control) mice (60 +/- 23 mg, n = 5). Moreover, the tumors in the treated mice were frequently surrounded by large lakes of clotted blood that were not evident in tumors from the control mice. Accelerated growth and blood clotting were also observed in tumor-bearing mice treated with heparinase I enzyme to destroy endogenous mast cell heparin and in NDST-2 knockout mice in which there is a targeted disruption in the gene coding for mast cell heparin synthesis. We conclude that imatinib mesylate accelerated the growth and peri-tumoral blood clotting of implants of mammary adenocarcinoma in mice. These results suggest that imatinib mesylate may have significant effects on mast cells infiltrating tumors, in addition to its other biologic activities. Our results also indicate that the mechanism of this effect may be related to the anticoagulant properties of mast cell heparin.
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PMID:Acceleration of tumor growth and peri-tumoral blood clotting by imatinib mesylate (Gleevec). 1286 22

An unexplained paradox of malignant melanoma is the apparent failure of the blood within the tumor to clot despite the presence of multiple factors that should promote blood clotting. Here we present histochemical evidence that human and murine melanomas are extensively infiltrated by abundant mast cells. Because mast cells contain the natural anticoagulant heparin, the present studies were aimed at defining the role of mast cell heparin in preventing the blood from clotting within B16 melanoma grafts in C57BL/6 J mice. Mice bearing B16 melanoma grafts were treated with non-specific or specific inhibitors of mast cell heparin (protamine or heparinase, respectively). After the drug treatment there was histologic and functional evidence of selective thrombosis of the blood vessels within the protamine and heparinase treated melanoma grafts. A similar, high degree of thrombosis was also observed in B16 tumors grown in transgenic NDST-2 knockout mice bearing a targeted disruption in the gene coding for mast cell heparin synthesis. The tumors grown in the protamine-treated animals were significantly smaller than the tumors from control (untreated mice). By contrast, the tumors treated with heparinase or grown in the NDST-2 knockout mice were significantly larger than the tumors from control (untreated) mice. We conclude that the intrinsic procoagulant properties of malignant melanoma are neutralized in vivo by the anticoagulant properties of endogenous heparin produced by mast cells that naturally infiltrate the tumor. Our results also suggest that thrombosis and hemostasis within melanoma may play a complex role in modulating the growth of the tumor.
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PMID:Inhibition of thrombosis in melanoma allografts in mice by endogenous mast cell heparin. 1288 84


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