The phosphatidylinositol 3-kinase inhibitor wortmannin blocks mast cell exocytosis but not IL-6 production.
The phosphatidylinositol 3-kinase inhibitor wortmannin blocks mast cell exocytosis but not IL-6 production.
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DOI：
10.4049/jimmunol.156.5.1942
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发表时间：
1996-03
影响因子：
4.4
通讯作者：
D. Marquardt;J. Alongi;L. Walker
中科院分区：
文献类型：
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作者：
D. Marquardt;J. Alongi;L. Walker
磷脂酰肌醇3-激酶（pi3 -激酶）活性已被证明在通过与酪氨酸激酶相关的受体和与小或异三聚体G蛋白偶联的受体的细胞信号传导中起重要作用。在高亲和IgE受体交联、钙直接内流和/或腺苷受体激动剂暴露刺激的小鼠骨髓源性肥大细胞中，研究了这种活性在肥大细胞脱颗粒、白三烯C4生成和IL-6产生中的重要性。Wortmannin是一种真菌代谢物，在纳摩尔浓度下相对特异性地抑制pi3激酶，阻断颗粒相关肥大细胞介质的释放，而不依赖于所使用的分泌刺激。这种抑制在wortmannin预孵育2至5分钟后最为显著，并且在另外用外源性n -乙基羧氨基腺苷处理以增强预形成介质释放的细胞中同样有效。在激活后20分钟或激活后16小时，肥大细胞白三烯C4的产生不受高达100 nM的wortmannin暴露的影响。用wortmannin预孵育的肥大细胞在银的攻击下没有表现出典型的颗粒肿胀和融合、膜皱褶增加或胞外分泌的电镜证据。pi3激酶的激活似乎对肥大细胞脱颗粒至关重要，但不是花生四烯酸代谢或细胞因子产生所必需的。此外，wortmannin对肥大细胞分泌的抑制不是刺激特异性的，但对IgE受体交联和直接钙内流都是明显的。
Phosphatidylinositol 3-kinase (PI3-kinase) activity has been shown to be important in cellular signaling via receptors associated with tyrosine kinases and receptors coupled to small or heterotrimeric G proteins. The importance of this activity in mast cell degranulation, leukotriene C4 generation, and IL-6 production was examined in mouse bone marrow-derived mast cells stimulated by high affinity IgE receptor cross-linking, direct influx of calcium, and/or adenosine receptor agonist exposure. Wortmannin, a fungal metabolite that at nanomolar concentrations inhibits PI3-kinase relatively specifically, blocked the release of granule-associated mast cell mediators independent of the secretory stimulus used. This inhibition was most prominent after a 2- to 5-min preincubation with wortmannin and was equally effective in cells additionally treated with exogenous N-ethylcarboxamidoadenosine to potentiate preformed mediator release. Mast cell production of leukotriene C4 20 min after activation or IL-6 16 h after activation was unaffected by up to 100 nM of wortmannin exposure. Mast cells preincubated with wortmannin failed to develop the classic electronmicroscopic evidence of granule swelling and fusion, increased membrane ruffling, or exocytosis upon Ag challenge. Activation of PI3-kinase appears to be critical for mast cell degranulation but is not required for arachidonic acid metabolism or cytokine production to occur. Furthermore, the inhibition of mast cell secretion by wortmannin is not stimulus specific but is evident for both IgE receptor cross-linking and direct calcium influx.