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)

REV 3164 has been evaluated in a variety of intact rodent models to reveal potential utility in the prophylactic treatment of asthma. REV 3164 was found a potent, orally active inhibitor of rat (IgE) passive cutaneous anaphylaxis (PCA, ED50 = 0.9 mg/kg). By contrast, at 50-200 mg/kg p.o., it did not affect guinea-pig (IgG1) PCA. In PCA rats, both REV 3164, 1-36 mg/kg i.p., and the known inhibitor of mast cell mediator release, disodium cromoglycate (DSCG), 2-54 mg/kg i.p., blocked cutaneous wheals caused by i.v. antigen challenge but not by intradermal serotonin or histamine. Neither REV 3164 (0.1-10 mg/kg i.p.) nor DSCG (2-54 mg/kg i.p.) affected Compound 48/80-induced wheals. REV 3164 (0.01-1 mg/kg i.v. or 10 mg/kg i.p.) abolished rat (IgE) passive lung anaphylaxis (PLA, ED50 = 0.05 mg/kg i.v. for inhibition of elevated airway resistance). At 10 mg/kg i.p., REV 3164 did not affect active lung anaphylaxis in guinea-pigs pharmacologically manipulated to enhance the production and action of slow reacting substance of anaphylaxis (SRS-A), nor did it exhibit anticholinergic activity in the rat. REV 3164 (100 mg/kg i.p.) did not protect conscious guinea-pigs from histamine aerosol-induced collapse. It is concluded that REV 3164 is an oral inhibitor of IgE-dependent immediate hypersensitivity in the rat with biological activities in rats and guinea-pigs similar to DSCG.
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PMID:In vivo anti-allergic and bronchopulmonary pharmacology of REV 3164 in rats and guinea-pigs. 649 6

Five 2-pyridinecarboxylic acid-related compounds (1, 2 and 5-7) showed germination inhibition against the seed of Brassica campestris L. subsp. rapa HOOK fil et ANDERS at a concentration of 5.0 x 10(-4) M. These compounds also demonstrated inhibitory activity on the growth of the root of this plant at a concentration of 3.0 x 10(-4) M; among these compounds, 2-pyridylacetic acid (5) showed the strongest inhibitory activity, and the effect was slightly stronger than that of sodium 2,4-dichlorophenoxyacetate (2,4-D) used as a positive control. The amounts of chlorophyll in the cotyledons of this plant treated with these active compounds was lower than that of the control group. Four compounds (1 and 5-7) with germination inhibition also showed inhibitory activities against alpha-amylase and carboxypeptidase A, and 5 was the strongest inhibitor toward both enzymes.
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PMID:Inhibitory activities of 2-pyridinecarboxylic acid analogs on phytogrowth and enzymes. 1059 34

Piratoxin-I (PrTX-I) is a Lys-49 phospholipase (PLA(2)) homologue, isolated from Bothrops pirajai snake venom, that has no phospholipase activity. In this study, we investigated the in vivo oedematogenic activity of PrTX-I in both the rat and the rabbit as well as the ability of PrTX-I to activate rat mast cells in vitro. In the rat paw and skin, PrTX-I (3-100 microg/paw) induced a dose-dependent oedema that was associated with extensive mast cell degranulation. The involvement of mast cells in PrTX-I-mediated oedema formation in the rat was further confirmed by the findings that this protein significantly activated rat peritoneal mast cells in vitro, causing the release of [(14)C]5-hydroxytryptamine ([(14)C]5-HT; 51 +/- 1%). In the rabbit, PrTX-I (10-100 microg/site) also induced dose-dependent skin oedema formation that was not affected by either mepyramine (a histamine H(1) receptor antagonist) or cyproheptadine (1.0 microg/site), indicating that mast cells do not play a role in this animal species. The bradykinin B(2) receptor antagonist Hoe 140 (0.5 microg/site) and the platelet-activating factor (PAF) receptor antagonist WEB 2086 (200 microg/site) also failed to affect the PrTX-I-induced rabbit skin oedema, ruling out the involvement of kinins and PAF. The PLA(2) inhibitor p-bromophenacyl bromide greatly reduced the PrTX-I-induced oedema in both the rat and the rabbit, and also inhibited the rat in vitro mast cell activation induced by this PLA(2) homologue. The polyanions heparin and dermatan sulphate efficiently prevented oedema formation in both species, and heparin inhibited PrTX-I-induced rat mast cell degranulation. Our results are consistent with the suggestion that the cationic charge of PrTX-I plays a major role in the inflammatory responses induced by this PLA(2) homologue.
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PMID:Inflammatory oedema induced by the lys-49 phospholipase A(2) homologue piratoxin-i in the rat and rabbit. Effect of polyanions and p-bromophenacyl bromide. 1073 29

Bothropstoxin-I (BthTX-I) and bothropstoxin-II (BthTX-II) are Lys-49 and Asp-49 phospholipases A(2) (PLA(2)s), respectively, isolated from Bothrops jararacussu venom. Piratoxin-I (PrTX-I) is a Lys-49 PLA(2) isolated from Bothrops pirajai venom. In this study, the ability of BthTX-I, BthTX-II and PrTX-I to recruit leucocytes into the rat pleural cavity and potential mechanisms underlying this effect were investigated. Intrapleural injection of either BthTX-I or PrTX-I (10-100 microg/cavity each) caused a significant leucocyte infiltration at 12 h after injection. The maximal cell migration was observed with the dose of 30 microg/cavity (14.9+/-15.5 and 17.6+/-1. 6x10(6) cells/cavity, respectively). Leucocyte counts consisted mainly of mononuclear cells, but significant amounts of neutrophils and eosinophils were also observed. Intrapleural injection of BthTX-II (10-100 microg/cavity) caused a marked leucocyte infiltration at 6 and 12 h after injection. The maximal response was observed with the dose of 100 microg/cavity (57.3+/-3.4x10(6) cells/cavity, 6 h). The leucocyte counts were mainly composed of neutrophils and mononuclear cells. The treatment of either BthTX-I (30 microg/cavity, 12 h) or BthTX-II (30 microg/cavity, 6 h) with the PLA(2) inhibitor p-bromophenacyl bromide (p-BPB) had no effect on the total and differential leucocyte counts induced by these proteins. The same treatment partially reduced the PrTX-I-induced pleural leucocyte infiltration. In rats depleted of the histamine and 5-hydroxytryptamine (5-HT) stores by chronic treatment with compound 48/80, the total leucocyte counts in response to BthTX-I, BthTX-II and PrTX-I was not significantly affected compared to control animals. In addition, BthTX-I, BthTX-II and PrTX-I (100 microg/ml each) significantly degranulated pleural mast cells in vitro leading to the release of [(14)C]5-hydroxytryptamine ([(14)C]5-HT). p-BPB and heparin (50 IU/ml) significantly reduced the [(14)C]5-HT release induced by these PLA(2)s. Our results demonstrate that BthTX-I, BthTX-II and PrTX-I recruit leucocyte into the pleural cavity of the rat by mechanisms unrelated to enzymatic activity and pleural mast cell degranulation.
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PMID:Leucocyte recruitment induced by type II phospholipases A(2) into the rat pleural cavity. 1085 16

Lysophosphatidylserine (1-acyl-2-lyso-PS) has been shown to stimulate histamine release from rat peritoneal mast cells (RPMC) triggered by FcepsilonRI (high affinity receptor for IgE) cross-linking, although the precise mechanism of lyso-PS production has been obscure. In the present study we show that phosphatidylserine-specific phospholipase A(1), PS-PLA(1), stimulates histamine release from RPMC through production of 2-acyl-1-lyso-PS in the presence of FcepsilonRI cross-linker. The potency of 2-acyl-1-lyso-PS was almost equal to that of 1-acyl-2-lyso-PS. A catalytically inactive PS-PLA(1), in which an active serine residue (Ser(166)) was replaced with an alanine residue did not show such activity. sPLA(2)-IIA, another secretory PLA(2) that is capable of producing lyso-PS in vitro, was also a poor histamine inducer against RPMC. PS-PLA(1) significantly stimulated histamine release from crude RPMC, indicating that lyso-PS is mainly derived from cells other than mast cells. In agreement with this phenomenon, the enzyme stimulated the histamine release more efficiently when RPMC were mixed with apoptotic Jurkat cells. Under these conditions, lyso-PS with unsaturated fatty acid was released from the apoptotic cells treated with PS-PLA(1). Finally, heparin, which has affinity for PS-PLA(1), completely blocked the stimulatory effect of the enzyme. In conclusion, PS-PLA(1) may bind to heparan sulfate proteoglycan, efficiently hydrolyze PS appearing on plasma membranes of apoptotic cells, and stimulate mast cell activation mediated by 2-acyl-1-lyso-PS.
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PMID:Phosphatidylserine-specific phospholipase A1 stimulates histamine release from rat peritoneal mast cells through production of 2-acyl-1-lysophosphatidylserine. 1139 20

This study tested the hypothesis that certain secretory phospholipase A(2) (sPLA(2)) isotypes act in a cytokine-like fashion through cell surface receptors to influence mast cell survival. Initial experiments revealed that sPLA(2) activity and sPLA(2) receptor expression are increased, and mast cells lost their capacity to maintain membrane asymmetry upon cytokine depletion. Groups IB and III, but not group IIA PLA(2), prevented the loss of membrane asymmetry. Similarly, group IB prevented nucleosomal DNA fragmentation in mast cells. Providing putative products of sPLA(2) hydrolysis to cytokine-depleted mast cells did not influence survival. Furthermore, catalytic inactivation of sPLA(2) did not alter its capacity to prevent apoptosis. Inhibition of protein synthesis using cycloheximide or actinomycin reversed the antiapoptotic effect of sPLA(2). Additionally, both wild-type and catalytically inactive group IB PLA(2) induced IL-3 synthesis in mast cells. However, adding IL-3-neutralizing Ab did not change Annexin V(FITC) binding and only partially inhibited thymidine incorporation in sPLA(2)-supplemented mast cells. In contrast, IL-3-neutralizing Ab inhibited both Annexin V(FITC) binding and thymidine incorporation in mast cells maintained with IL-3. sPLA(2) enhanced phosphoinositide 3'-kinase activity, and a specific inhibitor of phosphoinositide 3'-kinase reversed the antiapoptotic effects of sPLA(2). Likewise, sPLA(2) increased the degradation of I-kappaBalpha, and specific inhibitors of nuclear factor kappa activation (NF-kappaB) reversed the antiapoptotic effects of sPLA(2). Together, these experiments reveal that certain isotypes of sPLA(2) enhance the survival of mast cells in a cytokine-like fashion by activating antiapoptotic signaling pathways independent of IL-3 and probably via sPLA(2) receptors rather than sPLA(2) catalytic products.
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PMID:Enhancement of mast cell survival: a novel function of some secretory phospholipase A(2) isotypes. 1159 36

This study aim was to assess the effects of rebamipide on the mechanism of histamine release and biosynthesis and release of leukotrienes caused by mast cell activation. We purified mast cells from guinea pig lung tissues by the use of enzyme digestion, the rough and the discontinuous density percoll gradient method. Mast cells were sensitized with IgG1 (anti-OVA) antibody and challenged with ovalbumin. Mast cells were also stimulated with A23187 and the intracellular Ca(2+) level was measured. Histamine and leukotrienes were measured by automated fluorometric analyzer and radioimmunoassay, respectively. The intracellular Ca(2+) level was analyzed using a confocal laser scanning microscope. Protein kinase C (PKC) activity was determined by protein phosphorylated with [gamma-(32)P]ATP. The phospholipase D activity was assessed by the labeled phosphatidylalcohol. Mass 1,2-diacylglycerol (DAG) was measured by the [(3)H]DAG produced when prelabeled with [(3)H]myristic acid. PLA(2) activity was determined by measuring the arachidonic acid released from the labeled phospholipids. Rebamipide decreased the releases of histamine and leukotrienes, and completely blocked Ca(2+) influx during mast cell activation by antigen-antibody reactions. It also decreased the release of histamine and leukotrienes during mast cell activation by A23187. The PKC and PLD activities were also decreased by rebamipide in a dose-dependent manner. Rebamipide inhibited the mass DAG production and PLA(2) activity during mast cell activation. The data suggest that rebamipide inhibits intracellular signals and blocks Ca(2+) influx in mast cells activated by specific antigen-antibody reactions, which in turn inhibits histamine release and leukotriene generation.
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PMID:The inhibitory mechanism of rebamipide on the mediator release in the guinea pig lung mast cells activated with specific antigen-antibody reactions. 1159 24

Phospholipases A(2) (PLA(2)s), of molecular mass 13-15kDa, are commonly isolated from snake venom. Two myotoxins with PLA(2) activity, BaPLA(2)I and BaPLA(2)III, with estimated molecular masses of 15kDa were isolated from the venom of Bothrops atrox using Sephacryl S-100-HR and reverse-phase chromatography. BaPLA(2)I was basic, with a pI of 9.1, while BaPLA(2)III was neutral with a pI of 6.9. On a molecular basis, BaPLA(2)III exhibited higher catalytic activity on synthetic substrates than BaPLA(2)I. Comparison of the N-terminal residues of BaPLA(2)I with other PLA(2) proteins from snake venoms showed that it has the highest homology (94%) with B. asper myotoxin II and homology with a PLA(2) Lys(49) from B. atrox (89%). In contrast, BaPLA(2)III demonstrated 75, 72, and 71% homology with PLA(2) from Vipera ammodytes meridionalis, B. jararacussu, and B. jararaca, respectively. BaPLA(2)I and BaPLA(2)III were capable, in vitro, of inducing mast cell degranulation and, in vivo, of causing creatine kinase release, edema, and myonecrosis typical of PLA(2)s from snake venoms, characterized by rapid disruption of the plasma membrane as indicated by clumping of myofilaments and necrosis of affected skeletal muscle cells. BaPLA(2)I- and BaPLA(2)III-specific monoclonal and polyclonal antibodies, although incapable of neutralizing PLA(2) edematogenic activity, blocked myonecrosis efficiently in an in vivo neutralization assay. The results presented herein suggest that the biological active site responsible for edema induction by these two PLA(2) enzymes is distinct from the myonecrosis active site and is not dependent upon the catalytic activity of the PLA(2) enzyme.
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PMID:Biochemical and biological properties of phospholipases A(2) from Bothrops atrox snake venom. 1223 22

Recent studies have suggested that dual inhibitors of cyclooxygenase (COX) and lipoxygenase (LO) may be more beneficial in the treatment of inflammatory diseases in which platelet-leukocyte interaction dominates the underlying inflammatory process, than inhibitors of COX or LO alone. In this study, we examined oxygenated xanthones, shown previously to inhibit platelet and neutrophil activation, with respect to the potency of COX inhibition. 1,3,6,7-Tetrahydroxyxanthone (norathyriol) was the most potent. Norathyriol suppressed thromboxane B(2) (TXB(2)) and leukotriene B(4) (LTB(4)) formation in calcium ionophore (A23187)- and formyl-methionyl-leucyl-phenylalanine (fMLP)-stimulated rat neutrophils. Norathyriol was 3-4 times more active against LTB(4) formation than against TXB(2) formation (IC(50) about 2.8 vs. 10 microM, respectively). Norathyriol also inhibited prostaglandin D(2) (PGD(2)) formation in A23187-stimulated rat mast cells (IC(50) 3.0+/-1.2 microM) and in arachidonic acid (AA)-activated mast cell lysate. Norathyriol was a more effective inhibitor of 5-LO activity than of COX, as shown also by analyses of enzyme activities in a cell-free system, of COX and 5-LO metabolic capacity in neutrophils and of ex vivo TXB(2) and LTB(4) formation in A23187-stimulated neutrophils. Moreover, norathyriol inhibited COX-2 and 12-LO with IC(50) values (19.6+/-1.5 and 1.2+/-0.1 microM, respectively) similar to those required for the inhibition of COX-1 and 5-LO (16.2+/-1.5 and 1.8+/-0.4 microM, respectively). Inhibition of 15-LO by norathyriol was slightly less active. Norathyriol had no effect on A23187-induced AA release from neutrophils and did not affect phospholipase A(2) (PLA(2)) activity in a cell-free system. These results indicate that norathyriol inhibits the formation of PGs and LTs in neutrophils probably through direct blockade of COX and 5-LO activities. Norathyriol, a single molecule with multiple targets, might provide a potential therapeutic benefit in the treatment of inflammatory diseases.
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PMID:Inhibition of the arachidonic acid cascade by norathyriol via blockade of cyclooxygenase and lipoxygenase activity in neutrophils. 1508 66

Increased mast cell numbers and mast cell activation represent one of the prevalent etiologic theories for interstitial cystitis, an inflammatory condition in the bladder. This study was designed primarily to determine whether increased mast cell tryptase in the bladder wall may play a role in activating bladder endothelial cell phospholipase A(2) (PLA(2)), leading to increased inflammatory phospholipid metabolite accumulation, which may propagate the inflammatory process. We stimulated human bladder microvascular endothelial cells with thrombin or tryptase and measured the activation of PLA(2) and the production of multiple membrane phospholipid-derived inflammatory mediators. Thrombin and tryptase stimulation resulted in activation of a Ca(2+)-independent PLA(2), leading to increased release of arachidonic acid and prostacyclin and increased production of platelet-activating factor. These responses were blocked completely by pretreatment of human bladder microvascular endothelial cells with the Ca(2+)-independent PLA(2)-selective inhibitor bromoenol lactone. The combination of increased prostacyclin and platelet-activating factor in the bladder circulation may result in vasodilation and increased polymorphonuclear leukocyte adherence to the endothelium and may facilitate recruitment of polymorphonuclear leukocytes to the bladder wall of patients with interstitial cystitis.
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PMID:Protease-activated receptor stimulation activates a Ca2+-independent phospholipase A2 in bladder microvascular endothelial cells. 1556 75


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