IL-5 receptor activation and eosinophil signal transduction

(申请人摘要)这项研究建议的重点是描绘 白介素5(IL-5)家族细胞因子的调节机制 人类嗜酸性粒细胞的功能。这一目标的重要性在于 强调的是观察到IL-5家族细胞因子介导 嗜酸性粒细胞的招募和激活可能有助于 哮喘的病理生理特点。然而，IL-5通过的途径 受体信号转导与嗜酸性炎症的控制有关 人们对哮喘的认识还不够深入。在这方面，我们现在处于独特的 能够严谨地剖析特定IL-5的作用 人类嗜酸性粒细胞生物学调节中的信号事件 血液和呼吸道嗜酸性粒细胞。此外，我们还拥有三项关键功能 应该允许我们获得关于嗜酸性粒细胞生物学和 哮喘，包括：a)常规获得高度纯化的人血和呼吸道 嗜酸性粒细胞，包括从哮喘患者身上分离出来的嗜酸性粒细胞，b) 参与介导IL-5和IL-5的关键信号分子的鉴定 趋化因子在外周和呼吸道嗜酸性粒细胞中的作用，包括 Ras G蛋白超家族、MAP激酶(ERKs 1和2)以及几个 统计转录因子，以及c)分析方法的发展 人嗜酸性粒细胞中细胞因子/趋化因子信号的研究，包括一项技术 将显性-负性分子引入原始人 嗜酸性粒细胞。这些工具将用来检验IL-5的总体假设 受体信号转导和调节嗜酸性粒细胞功能的作用 Ras超家族的低分子量G蛋白，ERK1和ERK2，以及几种状态 因素，这些通路的作用不仅仅是调解直接的 IL-5相关细胞因子对嗜酸性粒细胞功能的影响 对启动血细胞对各种不同的 参与控制这一细胞的其他因素呢？S的炎症能力。 因此，建议开展以下调查工作：1)测试 RAS超家族G蛋白激活对IL-5至关重要的假设 增强人血嗜酸性粒细胞的炎症能力。2) 评价IL-5启动人血嗜酸性粒细胞反应的机制 趋化因子，并确定这种启动过程的要求如何 在呼吸道细胞中被绕过。3)考察STAT3和STAT5依赖的作用 IL-5介导的人嗜酸性粒细胞基因表达及调控途径 生物反应性。

(Applicant's Abstract) This research proposal is focused on delineating the mechanisms by which the interleukin-5 (IL-5) family of cytokines can regulate the function of the human eosinophil. The importance of this goal is emphasized by the observation that IL-5 family cytokines mediate the recruitment and activation of eosinophils that likely contributes to the pathophysiologic features of asthma. However, the pathways whereby IL-5 receptor signaling is coupled to the control of eosinophilic inflammation in asthma are not well understood. In this regard, we are now in the unique position of being able to rigorously dissect the role of specific IL-5 signaling events in the modulation of eosinophil biology using both human blood and airway eosinophils. In addition, we have three key capabilities that should permit us to obtain new insights regarding eosinophil biology and asthma, including: a) routine access to highly purified human blood and airway eosinophils, including eosinophils isolated from people with asthma, b) the identification of key signaling molecules involved in mediating IL-5 and chemokine action in peripheral and airway eosinophils, including members of the Ras G-protein superfamily, the MAP kinases (ERKs 1 and 2), and several STAT transcription factors, and c) the development of methods for the analysis of cytokine/chemokine signaling in human eosinophils, including a technique for the introduction of dominant-negative molecules into primary human eosinophils. These tools will be used to test the overall hypothesis that IL-5 receptor signaling and regulation of eosinophil function involves the action of low MW G-proteins of the Ras superfamily, ERKs 1 and 2, and several STAT factors, and that the role of these pathways is not only to mediate the direct effects of IL-5 related cytokines on eosinophil function, but that they are also critical for priming blood cells to become responsive to a variety of other factors involved in the control of this cell?s inflammatory capacity. Accordingly, the following lines of investigation are proposed: 1) Test the hypothesis that activation of Ras superfamily G-proteins is essential for IL-5 to enhance the inflammatory capacity of the human blood eosinophil. 2) Evaluate the mechanism whereby IL-5 primes human blood eosinophils to respond to chemokines and ascertain how the requirement for this priming processes is bypassed in airway cells. 3) Examine the role of STAT3- and STAT5-dependent pathways in IL-5-mediated regulation of human eosinophil gene expression and biological responsiveness.