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analyses of molecular mechanisms of mast cell activation in the innate immune and allergic reactions

先天免疫和过敏反应中肥大细胞激活的分子机制分析

基本信息

批准号：
15390163
负责人：
RA Chisei
金额：
$ 8.32万
依托单位：
Nihon University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
2003
资助国家：
日本
起止时间：
2003 至 2004
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-15390163/
关键词：
mast cell FcεRI Toll like receptors allergy innate immunity reactive oxygen species

项目摘要

1.Suppressive signals through the high affinity IgE receptor (FcεRI) β chainIn the FcεRI β chain ITAM mutant cells, activation of ERK, JNK and NF-κ B was significantly enhanced upon FcεRI crosslinking, although recruitment of Lyn, SHIP, and SHP to the β chain was severely impaired. Moreover, we revealed that C terminal region of the β chain positively regulated mast cell activation. β chain ITAM Tg are mated with β chain deficient mouse.2.Regulation of FcεRI β chain gene expressionThe transcription factor MZF-1 suppressed human FcεRI β chain gene expression via an element in the fourth intron. FHL3 was isolated from a human cDNA library as a repressive co-factor of MZF-1 by yeast two hybrid assays. GM-CSF induced translocation of FHL3 to the nucleus in addition to expression of MZF-1,suggesting that GM-CSF downregulated FcεRIβ expression through accumulation of MZF-1/FHL3 complex in the nucleus3.TLR signaling in mast cellsNF-kappa B activation by LPS was mediated via MyD88 dependent or independent pathways. We also demonstrated that PKR-dependent pathway regulated MyD88-independent NF-κ B activation.4.FcεRIβ-dependent or independent production of hydrogen peroxide in mast cellsWe explored the role of FcεRIβ in the production of H_2O_2 upon FcεRI cross-linking and found that the oxidant is produced through two distinct pathways : dependent or independent of FcεRIβ. The FcεRIβ-dependent production of H_2O_2 was mediated by the physical interaction with Lyn kinase via its immunoreceptor tyrosine-based activation motif, while the FcεRIβ-independent production of H_2O_2 appeared to be a result of intramitochondrial production of superoxide and its dismutation catalyzed by superoxide dismutase. Furthermore, while the FcεRIβ-dependent oxidative burst is required for maximal calcium store emptying, a prerequisite event for the initiation of store-operated calcium entry, the FcεRIβ-independent response seems to be involved in the prolongation of the calcium entry.

1.通过高亲和力IgE受体(FcεRI)β链的抑制信号在FcεRIβ链ITAM突变细胞中，FcεRI交联后ERK、JNK和NF-κB的活化显着增强，尽管Lyn、SHIP和SHP向β链的募集严重受损。此外，我们发现β链的C末端区域正向调节肥大细胞的激活。 β链ITAM Tg与β链缺陷小鼠交配。2.FcεRI β链基因表达的调节转录因子MZF-1通过第四内含子中的元件抑制人FcεRI β链基因表达。通过酵母两种杂交分析从人类 cDNA 文库中分离出 FHL3，作为 MZF-1 的抑制辅因子。除了MZF-1的表达外，GM-CSF还诱导FHL3易位至细胞核，这表明GM-CSF通过MZF-1/FHL3复合物在细胞核中的积累下调FcεRIβ的表达。肥大细胞中的TLR信号转导LPS通过MyD88依赖性或独立途径介导NF-κB激活。我们还证明了PKR依赖性途径调节MyD88独立的NF-κB激活。4.肥大细胞中FcεRIβ依赖性或独立的过氧化氢产生我们探索了FcεRIβ在FcεRI交联后产生H_2O_2中的作用，发现氧化剂是通过两种不同的途径产生的：依赖于FcεRIβ或独立于FcεRIβ。 H_2O_2 依赖于 FcεRIβ 的产生是通过其基于免疫受体酪氨酸的激活基序与 Lyn 激酶的物理相互作用介导的，而 H_2O_2 不依赖于 FcεRIβ 的产生似乎是线粒体内超氧化物产生及其由超氧化物歧化酶催化的歧化的结果。此外，虽然 FcεRIβ 依赖性氧化爆发是最大钙库排空所必需的，这是启动钙库操纵的钙进入的先决条件，但 FcεRIβ 独立反应似乎参与了钙进入的延长。