ABSTRACT
It has been reported that the glycoprotein extracted from Aloe has strong anti-inflammatory response. However, there has been no research report yet about the effect of Aloe on allergic hypersensitivity reactivity. By using guinea pig lung mast cells, this study aimed to examine the effects of Aloe glycoprotein (NY945) on the mediator releases caused by mast cell activation, and also aimed to assess the effects of NY945 on the mechanism of mediator releases in the mast cell activation. We partially purified mast cell from guinea pig lung tissues by using the enzyme digestion, the rough and the discontinuous density percoll gradient method. Mast cells were sensitized with IgG, (anti-OA) and challenged with ovalbumin. Histamine was assayed by fluorometric analyzer, leukotrienes by radioimmunoassay. The phospholipase D activity was assessed by the production of labeled phosphatidylalcohol. The amount of mass 1, 2-diacylglycerol (DAG) was measured by the (3H)-DAG produced when prelabeled with (3H)myristic acid. The phospholipid methylation was assessed by measuring the incorporation of the (3H)methyl moiety into phospholipids of cellular membranes. Pretreatment of NY945 (10 microgram) significantly decreased histamine and leukotrienes releases during mast cell activation. The decrease of histamine release was stronger than that of leukotriene during mast cell activation. The phospholipase D activity increased by the mast cell activation was decreased by the dose-dependent manner in the pretreatment of NY945. The amount of DAG produced by PLC activity was decreased by NY945 pretreatment. The amount of -mass 1, 2-diacylglycerol produced by activation of mast cells was decreased in the pretreatment of NY945. NY945 pretreatment strongly inhibited the incorporation of the (3H)-methyl moiety into phospholipids. The data suggest that NY945 purified from Aloe inhibits in part an increase of 1, 2-diacylglycerol which is produced by activating mast cells with antigen-antibody reactions, which is mediated via phosphatidylcholine-phospholipase D and phosphatidylinositol-phospholipase C systems, and then followed by the inhibition of histamine release. Furthermore, NY945 reduces the production of phosphatidylcholine by inhibiting the methyltransferase I and II, which decreases the conversion of phosphatidylcholine into arachidonic acid and inhibits the production of leukotrienes.
Subject(s)
Animals , Aloe , Antigen-Antibody Complex , Antigen-Antibody Reactions , Arachidonic Acid , Digestion , Glycoproteins , Guinea Pigs , Guinea , Histamine , Histamine Release , Hypersensitivity , Immunoglobulin G , Leukotrienes , Lung , Mast Cells , Membranes , Methylation , Ovalbumin , Phosphatidylcholines , Phospholipase D , Phospholipids , Radioimmunoassay , Research ReportABSTRACT
We previously reported that some components of ginsenosides decreased mediator releases evoked by the activation of mast cells with specific antigen-antibody reactions. This study aimed to assess the effects of ginsenosides (Rb2, Re) on the mechanism of histamine release in the mast cell activation. We partially purified guinea pig lung mast cells by using enzyme digestion, the rough and the discontinuous percoll density gradient method. Mast cells were sensitized with IgG1 and challenged with ovalbumin (OA). Histamine was assayed by fluorometric analyzer, leukotrienes by radioimmunoassay. Phospholipase D (PLD) activity was assessed more directly by the production of (3H)phosphatidylbutanol (PBut) which was produced by PLD-mediated transphosphatidylation in the presence of butanol. The amount of 1,2-diacylglycerol (DAG) were measured by the (3H)DAG labeled with (3H)palmitic acid or (3H)myristic acid. Pretreatment of Rb2 (300 microgram) significantly decreased histamine release by 60%, but Re (300 gg) increased histamine release by 34%. Leukotrienes release in Rb2 was decreased by 40%, Re was not affected in the leukotrienes release during mast cell activations. An increasing PLD activity during mast cell activation was decreased by the dose-dependent manner in the pretreatment of Rb2, but Re pretreatment facilitated the increased PLD activity during mast cell activation. The amount of DAG produced by phospholipase C (PLC) activity was decreased by Rb2 pretreatment, but Re pretreatment was not affected. The amount of mass DAG was decreased by Rb2 and Re pretreatment during mast cell activation. The data suggest that Rb2 purified from Korean Red Ginseng Radix inhibits the DAG which is produced by the activation of mast cells with antigen-antibody reactions via both phosphatidylinositide-PLC and phosphatidylcholine-PLD systems, and then followed by the inhibition of histamine release. However, Re increases histamine release by stimulation of DAG production, which is mediated by phosphatidylcholine-PLD system rather than by phosphatidylinositide-PLC system, but inhibits the mass DAG production. Thus, it could be inferred that other mechanisms play a role in the increase of histamine release during mast cell activation.
Subject(s)
Animals , Antigen-Antibody Reactions , Digestion , Ginsenosides , Guinea Pigs , Guinea , Histamine Release , Histamine , Immunoglobulin G , Leukotrienes , Lung , Mast Cells , Ovalbumin , Panax , Phospholipase D , Radioimmunoassay , Type C PhospholipasesABSTRACT
The inhibitory effect of cromakalim on the mediator release from mast cells caused by antigenantibody reactions was in controversy with the specific antigen used. However, it has recently been observed that cromakalim inhibits the release of mediators from superfused tracheal and parenchymal strips or lung mast cells after passive sensitization with the IgG1 antibody. An attempt, therefore, was made to determine the inhibitory mechanisms of cromakalim on the release of mediators such as histamine and leukotriene released by the activation of enzymes during mast cell activation. Guinea pig lung mast cells were purified through enzyme digestion, rough percoll and continuous percoll density gradients. The purified mast cells were prelabeled with [3H]palmitic acid. PLD activity was assessed more directly by the production of labeled phosphatidylethanol by PLD-mediated transphosphatidylation in the presence of ethanol. In the cells labelled with [3H]myristic acid, [3H] DAG production was measured. The methyltransferase activity was assessed by measuring the incorporation of [3H]methyl moiety into phospholipids in sensitized mast cells labelled with L-[3H] methylmethionine. cAMP level was measured by radioimmunoassay. Cromakalim resulted in a decrease in the amount of histamine and leukotrienes releases by 30% in the ovalumin-induced mast cell. Cromakalim had little effect on phospholipase D activity enhanced by the activated mast cell. Cromakalim inhibited the initial increase of diacylglycerol production during mast cell activations. Cromakalim inhibited the phospholipid methylation increased in the activated mast cell. These results show that cromakalim decreases histamine release by inhibiting the initial increase of 1,2-diacylglycerol during the mast cell activation, which is mediated via the phosphatidylinositide-phospholipase C system rather than the phosphatidylcholine-phospholipase D system. Furthermore, cromakalim reduces phosphatidylcholine production by inhibiting the methyltransferase, which decreases the conversion of phosphatidylcholine into arachidonic acid and inhibits the production of leukotrienes.
Subject(s)
Female , Adenylyl Cyclases/metabolism , Animals , Antigen-Antibody Reactions , Benzopyrans/pharmacology , Cromakalim , Diglycerides/biosynthesis , Guinea Pigs , Histamine Release/drug effects , Leukotrienes/metabolism , Lung/drug effects , Mast Cells/drug effects , Methylation , Phospholipase D/metabolism , Phospholipids/metabolism , Potassium Channels/drug effects , Pyrroles/pharmacologyABSTRACT
The inhibitory effect of cromakalim on the mediator release from mast cells caused by antigenantibody reactions was in controversy with the specific antigen used. However, it has recently been observed that cromakalim inhibits the release of mediators from superfused tracheal and parenchymal strips or lung mast cells after passive sensitization with the IgG1 antibody. An attempt, therefore, was made to determine the inhibitory mechanisms of cromakalim on the release of mediators such as histamine and leukotriene released by the activation of enzymes during mast cell activation. Guinea pig lung mast cells were purified through enzyme digestion, rough percoll and continuous percoll density gradients. The purified mast cells were prelabeled with [3H]palmitic acid. PLD activity was assessed more directly by the production of labeled phosphatidylethanol by PLD-mediated transphosphatidylation in the presence of ethanol. In the cells labelled with [3H]myristic acid, [3H] DAG production was measured. The methyltransferase activity was assessed by measuring the incorporation of [3H]methyl moiety into phospholipids in sensitized mast cells labelled with L-[3H] methylmethionine. cAMP level was measured by radioimmunoassay. Cromakalim resulted in a decrease in the amount of histamine and leukotrienes releases by 30% in the ovalumin-induced mast cell. Cromakalim had little effect on phospholipase D activity enhanced by the activated mast cell. Cromakalim inhibited the initial increase of diacylglycerol production during mast cell activations. Cromakalim inhibited the phospholipid methylation increased in the activated mast cell. These results show that cromakalim decreases histamine release by inhibiting the initial increase of 1,2-diacylglycerol during the mast cell activation, which is mediated via the phosphatidylinositide-phospholipase C system rather than the phosphatidylcholine-phospholipase D system. Furthermore, cromakalim reduces phosphatidylcholine production by inhibiting the methyltransferase, which decreases the conversion of phosphatidylcholine into arachidonic acid and inhibits the production of leukotrienes.