Regulation of mediator release from human mast cell by extracellular adenosine.

描述(由申请人提供)： 这项建议旨在建立G蛋白偶联的腺苷受体(ADORs)与成熟人类肥大细胞上的FCE/YRS之间的分子联系，以帮助解释腺苷对哮喘等人类过敏性疾病的影响。胞外腺苷(ExtADO)是一种嘌呤核苷，吸入后可引起支气管痉挛，并促进哮喘患者(但不是正常患者)的肥大细胞脱颗粒。因此，它与哮喘的发病机制有关。四种G蛋白偶联的腺苷受体(A1AR、A2aAR、A2bAR和A3AR)已被鉴定和鉴定。然而，尽管间接证据表明A2bAR参与了extADO对人类呼吸道肥大细胞的影响，但对extADO对人呼吸道肥大细胞的影响的责任尚不清楚。已经描述了两种类型的人肥大细胞，MCTC和MCT。皮肤来源的MCTC细胞表达类胰蛋白酶、凝乳酶、羧基肽酶A3和组织蛋白酶G，而MCT细胞仅表达类胰蛋白酶，是肺中的优势细胞。我们的初步数据显示，高extADO(10-4M)抑制FceRI介导的MCTC(皮肤)肥大细胞脱颗粒，而低extADO(10-7M)促进MCT(肺)肥大细胞释放介质。因此，这表明extADO对这些不同类型的人肥大细胞的介质释放有不同的调节作用。ExtADO还可促进IL-13的分泌，但抑制MCTC细胞产生PGD2、肿瘤坏死因子α、GM-CSF和IL-6，并抑制核因子-KB的激活。这项拟议的研究将表征extADO对通过FceRI和FcyR11a激活的MCTC和MCT型肥大细胞释放介质的影响，FcyR11a是本实验室最近发现的一种激活的Ig G受体，在皮肤MCTC上有成分地表达，可能在肺MCT细胞上表达，并确定对这两种类型的肥大细胞的不同作用的负责人(S)。SYK激酶和src酪氨酸激酶Fyn和Lyn是FceRI依赖的脱颗粒的关键调节因子，将作为MCTC和MCT肥大细胞中ADAR信号的靶标进行分析。抑制核因子-kB的激活也将被评估为产生IL-13的一般机制。过敏和哮喘是美国人主要的健康问题。了解这些疾病的细胞成分和调节这些细胞类型的分子机制，对于我们努力减轻这些疾病造成的个人和社会负担是最有意义的。(摘要结束)

DESCRIPTION (provided by applicant): This proposal aims to establish a molecular link between G protein-coupled adenosine receptors (ADORs) and Fce/yRs on mature human mast cells to help explain the impact of adenosine on human allergic diseases such as asthma. Extracellular adenosine (extADO) is a purine nucleoside that when inhaled causes bronchospasm and enhances degranulation of mast cells in human asthmatic (but not in normal) airways. Thus, it is implicated in asthma pathogenesis. Four G protein-coupled adenosine receptors (A1AR, A2aAR, A2bAR and A3AR) have been identified and characterized. However, the ADOR responsible for the effect of extADO on human airway mast cells is not clear, though indirect evidence suggests A2bAR is involved. Two types of human mast cells, MCTC and MCT, have been described. MCTC cells from skin express tryptase, chymase, carboxypeptidase A3 and cathepsin G; whereas MCT cells express tryptase alone and are the predominant type in lung. Our preliminary data reveal that high extADO (10-4 M) inhibits FceRI-mediated degranulation of MCTC (skin) mast cells, whereas low extADO (10-7 M) augments mediator release from the MCT (lung) mast cells. Thus, indicating that extADO differentially regulates mediator release from these distinct types of human mast cells. extADO also augments secretion of IL-13, a Th2 cytokine implicated in asthma pathogenesis, but inhibits production of PGD2, TNF a, GM CSF and IL 6 from MCTC cells and inhibits NF-KB activation. The proposed research will characterize the effect of extADO on mediator release from the MCTC and MCT types of mast cells activated through FceRI and also FcyRlla, an activating IgG receptor recently discovered in this lab to be constitutively expressed on skin MCTC and, possibly, on lung MCT cells, and identify the ADOR(s) responsible for the observed contrasting effects on these two types of human mast cells. Syk kinase and src tyrosine kinases Fyn and Lyn, key regulators of FceRI-dependent degranulation, will be analyzed as targets of ADOR signals in MCTC and MCT mast cells. Repression of NF-KB activation will also be assessed as a general mechanism for IL-13 production. Allergies and asthma are major health concerns in the United States. Understanding the cellular components of these disorders and the molecular mechanisms that regulate these cell types is of prime interest in our efforts to alleviate the personal and societal burdens due to these disorders. (End of Abstract)