CHEMOKINE INDUCTION BY RECEPTOR MEDIATED PHAGOCYTOSIS

这是一个修改后的应用程序的建议，研究细胞内的 导致促炎因子表达的信号转导途径 当巨噬细胞遇到肺中的颗粒时，趋化因子。肺泡 肺的区域持续暴露于吸入的颗粒， 包括惰性微粒和气溶胶化的病原体。 肺泡 巨噬细胞（AM）主要负责清除这些 颗粒从肺部，并启动和传播“适当的” 炎症反应。对颗粒结合和/或吞噬作用的反应 的AM是取决于所遇到的粒子的特性。 巨噬细胞表面受体与调理颗粒的结合 导致大量的呼吸爆发，随后增加 促炎细胞因子（包括血小板）的mRNA转录物 因子-4家族趋化因子、巨噬细胞炎性蛋白-2（MIP-2）和 KC. 我们假设肺部炎症是在吸入 颗粒被调理并被肺泡巨噬细胞吸收， 特异性表面受体，其介导细胞内信号， 激活MIP-2和KC基因的转录。 的性质 介导MIP-2/KC基因诱导的细胞内信号 表达是未知的，然而，我们提出了大量的初步数据， 涉及活性氧（ROS）作为主要刺激， 诱导这些mRNA。 我们建议使用分子和生物化学 以双向方式定义该转导途径的技术 从巨噬细胞膜上的刺激和 响应，MIP-2/KC mRNA合成。研究的具体目标是， 建议：（l）确定在下列情况下运作的管理机制： 巨噬细胞结合调理颗粒增加MIP-2和KC mRNA （2）克隆并鉴定MIP-2的5 '侧翼区 （3）鉴定推定的顺式元件，并建立它们的 在控制MIP-2和KC基因转录中的作用;和（4） 确定活性氧物质是信号关键成分 诱导MIP-2和KC基因表达的转导途径。阐明 调理颗粒诱导趋化因子合成的途径将 大大增加了我们对肺部炎症的理解， 相关疾病。

This is a revised application of a proposal to study the intracellular signal transduction pathway which leads to expression of pro-inflammatory chemokines when macrophages encounter particles in the lung. Alveolar regions of the lung are continuously exposed to inhaled particles, including both inert particulates and aerosolized pathogens. Alveolar macrophages (AMs) are primarily responsible for clearance of these particles from the lung, and for initiating and propagating a "proper" inflammatory response. Responses to particle binding and/or phagocytosis of AMs is dependent upon characteristics of the particles encountered. Binding of opsonized particles by cell surface receptors of macrophages results in a substantial respiratory burst and subsequently increases in mRNA transcripts for pro-inflammatory cytokines including the Platelet Factor-4 family chemokines, macrophage inflammatory protein-2 (MIP-2) and KC. We hypothesize that pulmonary inflammation is induced when inhaled particles are opsonized and taken up by alveolar macrophages using specific surface receptors which transduce intracellular signals to activate transcription of the MIP-2 and KC genes. The nature of the intracellular signal(s) that mediate the induction of MIP-2/KC gene expression is unknown, however, we present substantial preliminary data implicating reactive oxygen species (ROS) as the primary stimulus for induction of these mRNAs. We propose to use molecular and biochemical techniques to define this transduction pathway in a bi-directional fashion starting from both the stimulus at the macrophage cell membrane and the response, MIP-2/KC mRNA synthesis. The specific aims of the studies we propose are: (l) To determine the regulatory mechanisms operative when macrophage binding of opsonized particles increases MIP-2 and KC mRNA levels; (2) To clone and characterize the 5'-flanking regions of the MIP-2 and KC genes; (3) To identify putative cis elements and establish their role in controlling transcription of the MIP-2 and KC genes; and (4) To establish that reactive oxygen species are a key component of the signal transduction pathway inducing MIP-2 and KC gene expression. Elucidation of the pathway by which opsonized particles induce chemokine synthesis will add significantly to our understanding of pulmonary inflammation and associated diseases.