EFFECT OF INTERLEUKIN 5 RECEPTOR ACTIVATION ON EOSINOPHIL SIGNAL TRANSDUCTION

白细胞介素 5 受体激活对嗜酸性粒细胞信号转导的影响

• 批准号: 6302440
• 负责人: PAUL JOHN BERTICS
• 金额: $ 22.9万
• 依托单位: UNIVERSITY OF WISCONSIN-MADISON
• 依托单位国家: 美国
• 财政年份: 1999
• 资助国家: 美国
• 起止时间: 1999-12-01 至 2000-11-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6302440
• 关键词: antiport; apoptosis; asthma; cell adhesion; chemotaxis; cytokine receptors; enzyme activity; eosinophil; human tissue; immunoregulation; inflammation; integrins; interleukin 5; leukotrienes; mitogen activated protein kinase; phosphorylation; receptor binding; receptor expression; tissue /cell culture; transcription factor

Allergic inflammation and asthma are characterized by eosinophilia and the increased production of interleukin 5 (Il-5) in blood and affected tissues. Eosinophils can promote both bronchial smooth muscle contraction and increased permeability of bronchial mucosa. Eosinophil- derived mediators [e.g., granule proteins, reactive oxygen species and leukotriene C4 (LTC4)], can evoke hyper-responsiveness, epithelial damage, inflammation and bronchoconstriction. IL-5 is known to regulate eosinophil function, which can contribute to the pathogenesis of asthma. For example, IL-5 stimulation of blood eosinophils can produce several functional changes that mirror the phenotypic characteristics of the airway eosinophil, and these IL-5-induced changes include the priming LTC4 release, the increased membrane expression of CD11b/CD18, the enhance adherence to endothelial cells, and prolonged survival. Because little is known about IL-5 signal transduction in eosinophils, the present project is designed to explore the mechanisms by which Il-5 mediates alterations in eosinophil function, thereby increasing its inflammatory potential. This proposal will test a model of IL-5 intracellular signaling processes that is based on studies by us and others on the IL-5 family of cytokines. Our overall goal is to assess the importance of various aspects of this model to the intracellular events in human eosinophils stimulated with IL-5, and to relate these signaling processes to eosinophil function. The studies will focus on functional changes, namely chemotaxis, adherence to endothelium, LTC4 generation and suppression of apoptotic cell death, that are of particular relevance to the inflammatory capacity and accumulation of eosinophils in the pathogenesis of asthma. The proposed research centers around our observation that IL-5 stimulates the tyrosine phosphorylation of several cellular proteins, including the phosphorylation and activation of a 45-kDa mitogen- activated protein kinase (MAP kinase). The central hypothesis is developed that multiple pathways are involved in the IL-5 mediated tyrosine phosphorylation and activation of MAP kinases in eosinophils. To test this hypothesis, we will analyze the events that link IL-5 receptor activation to MAP kinase stimulation, such as pathways encompassing tyrosine kinases, Ras, protein kinase C, and/or pertussis toxin-sensitive G-proteins. Secondly, we will also examine selected processes that may result from IL-5-stimulated MAP kinase activity, including the regulation of phospholipase A2, ribosomal S6 kinase II (Rsk) and the hematopoietic transcription factor GATA-2, since these proteins are established MAP kinase substrates. These investigations lead to the related hypothesis that MAP kinase activation is a key intracellular mechanism, that along with other signaling events, is associated with IL-5 mediated changes in eosinophil function, including the priming of LTC4 generation, increased adherence to endothelial cells, chemotaxis and suppression of apoptotic cell death. In sum, it is anticipated that these studies will lead to a greater understanding of the molecular processes associated with eosinophilic inflammation that is a major characteristic of the pathophysiology of asthma.

过敏性炎症和哮喘的特征是嗜酸性粒细胞增多， 白细胞介素5（IL-5）在血液中的产生增加， 组织中 嗜酸性粒细胞可促进支气管平滑肌 支气管粘膜收缩和通透性增加。 嗜酸性粒细胞 衍生的介体[例如，颗粒蛋白质、活性氧物质和 白三烯C4（LTC 4）]，可引起高反应性，上皮细胞 损伤、炎症和支气管收缩。 已知IL-5调节 嗜酸性粒细胞功能，这可能有助于哮喘的发病机制。 例如，血液嗜酸性粒细胞的IL-5刺激可以产生几种细胞因子。 功能变化，反映了表型特征， 气道嗜酸性粒细胞，这些IL-5诱导的变化包括启动 LTC 4的释放，CD 11b/CD 18的膜表达增加， 增强对内皮细胞的粘附，并延长存活。 因为 对IL-5在嗜酸性粒细胞中的信号转导知之甚少， 本项目旨在探索IL-5 介导嗜酸性粒细胞功能的改变，从而增加其 潜在的炎症 该提案将测试IL-5的模型 细胞内信号传导过程是基于我们的研究， 其他人对IL-5家族的细胞因子。 我们的总体目标是评估 该模型的各个方面对细胞内 IL-5刺激的人嗜酸性粒细胞中的事件，并将这些事件与 嗜酸性粒细胞功能的信号传导过程。 研究将集中在 功能变化，即趋化性、内皮粘附、LTC 4 产生和抑制凋亡性细胞死亡， 特别是与炎症的能力和积累， 嗜酸性粒细胞在哮喘发病中的作用 这项研究的中心是我们观察到的IL-5 刺激几种细胞蛋白质的酪氨酸磷酸化， 包括45-kDa丝裂原的磷酸化和活化， 活化蛋白激酶（MAP激酶）。 核心假设是 研究表明，IL-5介导的细胞凋亡中涉及多种途径。 嗜酸性粒细胞中的酪氨酸磷酸化和MAP激酶的活化。 为了验证这一假设，我们将分析与IL-5 受体激活MAP激酶刺激，如通路 包括酪氨酸激酶、Ras、蛋白激酶C和/或百日咳 毒素敏感性G蛋白 第二，我们也会选择 可能由IL-5刺激的MAP激酶活性引起的过程， 包括磷脂酶A2、核糖体S6激酶II (Rsk)和造血转录因子加塔-2，因为这些 蛋白质是确定的MAP激酶底物。 这些调查 导致相关的假设，即MAP激酶激活是一个关键， 细胞内机制，沿着其他信号事件， 与IL-5介导的嗜酸性粒细胞功能变化相关，包括 LTC 4产生的引发，增加对内皮细胞的粘附， 细胞、趋化性和抑制凋亡性细胞死亡。 总之， 预计这些研究将使人们更好地了解 与嗜酸性粒细胞性炎症相关的分子过程 这是哮喘病理生理学的主要特征。