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

1. Intradermal or subplantar injection of soluble snake venom phospholipase A2 (PLA2) evoked a brisk inflammatory response, with cutaneous vascular permeability increase and paw oedema. 2. These inflammatory processes are mainly the result of arachidonic acid cascade activation and mast cell degranulation. 3. Copper, iron and zinc have an inhibitory effect on vascular permeability increase and paw oedema induced by PLA2. 4. Copper and iron could have not only a direct effect on PLA2 but on enzymes of arachidonic acid cascade. 5. However, zinc have a moderate antiinflammatory activity. This effect could be the result to inhibit PLA2 induced mast cell degranulation.
 ...
PMID:Effects of copper, iron and zinc on oedema formation induced by phospholipase A2. 135 48

Changes in the activities of three gastric and nine pancreatic enzymes plus colipase were determined during postnatal development and weaning in calves. In calves exclusively milk-fed for 2, 7, 28, 56, 70 and 119 d, the enzyme activities per kilogram of empty live weight increased with age for chymotrypsin, elastase, carboxypeptidases A and B, ribonuclease and alpha-amylase, decreased for chymosin, lysozyme and colipase but showed no change in the case of pepsin, trypsin, lipase and phospholipase A2 compared with animals at birth. The greatest increase was that in alpha-amylase activity (about 50-fold between d 2 and 119). In calves weaned between d 28 and 56, all the activities were higher than in milk-fed animals, except that of chymosin (which was slightly lower) and that of colipase (which did not change). At 119 d of age, chymotrypsin, carboxypeptidase A, alpha-amylase and lipase were 1.6- to fourfold higher in ruminants than in preruminants. Thus, most enzyme activities were modified first by colostrum and milk intake, and again upon weaning by development of the forestomachs and ingestion of solid food. These ontogenic patterns might be under the control of many gut regulatory peptides, the plasma concentrations of which changed simultaneously. Some gastric and pancreatic enzymes were correlated to plasma concentrations of these gut regulatory peptides.
 ...
PMID:Gastric and pancreatic enzyme activities and their relationship with some gut regulatory peptides during postnatal development and weaning in calves. 137 46

Phospholipase A2 activity in lysates of mast cells and their related cells [mouse bone marrow-derived IL-3 dependent mast cells (BMMC), rat connective tissue mast cells (CTMC), and rat mastocytoma RBL-2H3 cells] was measured using phosphatidylethanolamine (PE), phosphatidylserine (PS), and phosphatidylcholine (PC) as exogenous substrates. Both BMMC and RBL cells showed rather high phospholipase A2 activity, whereas CTMC showed only weak activity. These cells contained at least three types of phospholipase A2. Type 1 enzyme showed no appreciable affinity to heparin, and preferentially hydrolyzed either PC or PE, both of which have an arachidonic acid at the sn-2 position. The activity was absorbed by monoclonal antibody against rabbit platelet cytosolic 85-kDa phospholipase A2. Type 2 enzyme had an affinity to heparin, and was completely inhibited by anti-rat platelet 14-kDa secretory phospholipase A2. This enzyme could be expressed as an "ecto-type" enzyme on the cell surface and might be secreted from cells when mast cells are activated. Type 3 enzyme also had an affinity to heparin, but was separated from type 2 enzyme on reverse-phase HPLC. This enzyme did not interact with anti-14-kDa secretory enzyme antibody. Purified type 3 enzyme (30-kDa) specifically hydrolyzed PS. p-Bromophenacylbromide inhibited all types of phospholipase A2, whereas mepacrine inhibited type 2 and type 3 enzymes, but not type 1 enzyme. Type 2 enzyme was also inhibited by the specific antibody, complement degradation product, and a small-molecular-weight inhibitor. Histamine release was inhibited by all these inhibitors, whereas PGD2 production was inhibited only by p-bromophenacylbromide. Possible roles for these phospholipases A2 in mast cell function are proposed.
 ...
PMID:Characteristics and possible functions of mast cell phospholipases A2. 163 97

The edema-producing activity of NNAVPLA2, an acidic phospholipase A2 (PLA2) enzyme from Naja naja atra venom (NNAV), was less potent than that of TMVPLA2 II, a basic PLA2 from Trimeresurus mucrosquamatus venom (TMV). These edema-forming effects were greatly suppressed by pretreatment of rats with diphenhydramine/methysergide or compound 48/80, which reduced the tissue content of histamine and serotonin. Heparin abolished and suppressed the paw edema caused by protamine and TMVPLA2 II, respectively, but had no effect on the NNAVPLA2-induced response. In isolated rat peritoneal mast cells, both PLA2 concentration dependently induced the release of histamine and beta-glucuronidase. Again, TMVPLA2 II was more potent than NNAVPLA2. This degranulation effect of mast cells caused by TMVPLA2 II and protamine was inhibited by heparin, while that caused by NNAVPLA2 was unaffected. The edema-forming and mast cell degranulation effects were greatly decreased in both PBPB-modified NNAVPLA2 and PBPB-modified TMVPLA2 II, in which the catalytic activity of the enzymes was completely lost. PBPB-modified TMVPLA2 II-induced paw edema was also suppressed by heparin. Furthermore, this edematous response was totally reversed in rat pretreated with aspirin in combination with diphenhydramine and methysergide. These results suggest that the edema-forming effect of PLA2 is probably dependent on the presence of catalytic, positive charge and pharmacological sites on its molecule.
 ...
PMID:Comparison of the enzymatic and edema-producing activities of two venom phospholipase A2 enzymes. 170 83

Two phospholipase A2 (PLA2) enzymes, TMVPLA2 I and TMVPLA2 II, isolated from Trimeresurus mucrosquamatus venom (TMV) induce rat hind-paw oedema in a dose-dependent manner. This response is suppressed by pretreatment with diphenhydramine, methysergide or compound 48/80, which reduces tissue histamine content. In isolated mast cells, TMVPLA2 I and TMVPLA2 II cause concentration-, time- and calcium-dependent release of histamine and beta-glucuronidase. This effect is inhibited by disodium cromoglycate, mepacrine, nordihydroguaiaretic acid, piriprost and BW 755C, but not by aspirin or indomethacin. These observations indicate that the mast cell plays a predominant role in TMVPLA2 I- and TMVPLA2 II-induced paw oedema, and that venom PLA2 enzyme needs an intact lipoxygenase pathway to induce mast cell degranulation.
 ...
PMID:Rat paw oedema and mast cell degranulation caused by two phospholipase A2 enzymes isolated from Trimeresurus mucrosquamatus venom. 171 67

Rat peritoneal mast cells were sensitized with IgE and challenged with the specific antigen in the presence of lysophosphatidylserine (lysoPS), an essential co-factor for rodent connective tissue mast cell degranulation, and the effects of phospholipase A2 inhibitors were examined. Mepacrine, a known inhibitor of phospholipase A2, at concentrations below 10(-5) M and anti-rat 14-kDa group II phospholipase A2 antibody inhibited histamine release, while they did not affect the prostaglandin generation. Like histamine release, prostaglandin generation in IgE- and antigen- challenged rat peritoneal mast cells was dependent on the presence of lysoPS. These results indicate that 14-kDa group II phospholipase A2 may play an essential role in IgE-, antigen-, and lysoPS-dependent degranulation process of rat peritoneal mast cells and that the mechanism whereby it participates may not be due to the production of lysoPS from PS in mast cell membranes.
 ...
PMID:Group II phospholipase A2 inhibitors suppressed lysophosphatidylserine-dependent degranulation of rat peritoneal mast cells. 172 8

The extracellular form of 14-kDa group II phospholipase A2 has been found to accumulate at various types of inflammatory sites. In the present paper, we have studied the possible role of the extracellular 14-kDa group II phospholipase A2 in the process of prostaglandin production in activated rat mast cells. When mast cells obtained from the peritoneal cavity of rats were sensitized with IgE, challenged with antigen and then exposed to extracellular 14-kDa group II phospholipase A2, appreciable release of prostaglandin D2 was observed. Generation of prostaglandin D2 was dependent on the concentration of the phospholipase A2 as well as that of the antigen, while no appreciable prostaglandin D2 generation was observed with cells in the absence of the antigen. No histamine release was observed under the same conditions. Phosphatidylcholine in mast cell membranes was appreciably hydrolyzed to liberate free arachidonic acid when mast cells were incubated with 14-kDa group II phospholipase A2 added exogenously in the presence of the antigen. Both the generation of prostaglandin D2 and the release of arachidonic acid were retarded by inhibitors specific to 14-kDa group II phospholipase A2. Thus, 14-kDa group II phospholipase A2 may function in the process of inflammation by acting on IgE-antigen-primed mast cells, which are not fully activated, to generate eicosanoids.
 ...
PMID:Eicosanoid generation from antigen-primed mast cells by extracellular mammalian 14-kDa group II phospholipase A2. 175 67

Lysophosphatidylcholine (lyso-PC), a natural product of phospholipase A2 activity, induced the secretion of both granule-associated beta-hexosaminidase and newly generated leukotriene C4 from mouse bone marrow-derived mast cells. Micromolar concentrations of lyso-PC potentiated the release of beta-hexosaminidase induced by specific antigen but not the calcium ionophore, A23187. Exogenous adenosine was relatively ineffective in enhancing beta-hexosaminidase release from cells challenged with lyso PC. Lyso-PC caused a marked increase in intracellular free-calcium levels and induced the activation of protein kinase C (PKC). These effects could not be abrogated by a prolonged preincubation with pertussis toxin. Staurosporine, an inhibitor of PKC, partially inhibited the abilities of antigen and A23187 to induce beta-hexosaminidase release but was ineffective when lyso-PC was the secretagogue. Lyso-PC appears to activate mast cell PKC, but its ability to stimulate mast cell mediator release appears to be related to its ability to elevate intracellular free calcium concentrations.
 ...
PMID:Lysophosphatidylcholine induces mast cell secretion and protein kinase C activation. 183 66

Rapid incorporation of exogenous arachidonic acid into phospholipid has been detected in conjunction with eicosanoid synthesis by purified mast cell granules [Chock, S. P. & Schmauder-Chock, E. A. (1988) Biochem. Biophys. Res. Commun. 156, 1308-1315]. The species of phospholipid formed has now been identified primarily as phosphatidylinositol. A calcium-dependent phospholipase A2 has also been detected in the secretory granule. This enzyme, like the cyclooxygenase [Schmauder-Chock, E. A. & Chock, S. P. (1989) J. Histochem. Cytochem. 37, 1319-1328], appears to bind tightly to the granule matrix components. It is heat resistant and requires millimolar concentrations of calcium for optimal activity. It prefers phosphatidylinositol over phosphatidylcholine as substrate. Since the granule contains a large amount of phospholipid, the action of this phospholipase A2 can provide the required substrate for the arachidonic acid cascade. These findings provide the basis for linking phospholipase A2 to the production of eicosanoids during granule exocytosis. Since the granule also contains both an active acylating system that can rapidly reacylate lysophosphatidylinositol to form phosphatidylinositol, and an active phospholipase A2 which hydrolyzes phosphatidylinositol, a rapid turnover involving the fatty acid at the sn-2 position of phosphatidylinositol may occur. These findings are consistent with our postulation that the secretory granule is the source and/or the cause of many of the early biochemical events associated with the process of stimulus-secretion coupling.
 ...
PMID:Linking phospholipase A2 to phospholipid turnover and prostaglandin synthesis in mast cell granules. 190 Feb 37

The synthesis of platelet-activating factor (PAF) and of the 1-acyl analogue of PAF, 1-acyl-2-acetyl-sn-glycero-3-phosphocholine (1-acyl-2-acetyl-GPC) was examined in seven human cell preparations (lung mast cell, basophil, endothelial cell, neutrophil, eosinophil, lung macrophage, platelet) and in human lung fragments. Cells were activated by either an appropriate receptor-mediated stimulus or by ionophore A23187 in the presence of [3H]acetate. All cell types, with the exception of the platelet, responded to stimulation with at least a twofold increase in the formation of labeled 1-radyl-2-acetyl-GPC as compared with control values. A23187 was the more potent stimulus in all cell types examined except the lung mast cell, in which anti-IgE consistently induced the synthesis of more 1-radyl-2-acetyl-GPC. Human lung fragments stimulated by anti-IgE, Ag Amb a I (after passive sensitization), or A23187 also incorporated [3H]acetate into 1-radyl-2-acetyl-GPC. Subclass analysis of 1-radyl-2-acetyl-GPC produced by each cell indicated that the cell types examined can be divided into two groups according to the predominant type of 1-radyl-2-acetyl-GPC produced. Some cell types (mast cell, basophil, endothelial cell) produced predominantly 1-acyl-2-acetyl-GPC, whereas others (neutrophil, eosinophil, lung macrophage) produced almost exclusively PAF. In some cell types, such as the lung mast cell and the basophil, A23187 stimulation increased the synthesis of PAF relative to 1-acyl-2-acetyl-GPC as compared with anti-IgE stimulation. In the lung fragments, [3H]acetate was predominantly incorporated into 1-acyl-2-acetyl-GPC upon IgE-mediated stimulation (anti-IgE, Amb a I) and into PAF upon A23187 stimulation. The differential production of these two phospholipids was confirmed by determining their sensitivity to lipase A1 and phospholipase A2 hydrolysis and by HPLC. These data demonstrate that 1-acyl-2-acetyl-GPC can be synthesized by a variety of human cells involved in the inflammatory reaction. This finding raises fundamental questions about the biologic role of this molecule and the factors regulating its synthesis within inflammatory cells.
 ...
PMID:Differential synthesis of 1-acyl-2-acetyl-sn-glycero-3-phosphocholine and platelet-activating factor by human inflammatory cells. 207


1 2 3 4 5 6 Next >>