Regulation of Macrophage Activation by House Dust Mite

描述（由申请人提供）： 在伊拉克服役的美国士兵患过敏性鼻炎和哮喘的风险增加。部署在波斯湾的士兵患过敏性鼻炎的风险是本土驻扎人员的两倍，患哮喘的风险是本土驻扎人员的1.6倍。此外，在12岁以后诊断出哮喘症状是入伍的排除标准。虽然过敏性炎症性疾病风险增加的原因尚未确定，但暴露于高水平的灰尘和其他吸入颗粒被认为是最可能的解释。普遍存在的环境过敏原，屋尘螨（HDM），在伊拉克服役的士兵的帐篷中发现了高水平的过敏原，并且被认为是哮喘的主要诱因。据估计，50-80%的鼻炎和哮喘是由于HDM;然而，HDM诱导和加重哮喘的机制尚未完全了解。 HDM和许多其它吸入颗粒含有我们称为过敏原相关分子模式（AAMP）的刺激性结构，其接合并刺激先天模式识别受体（PRR）。虽然其他人已经研究了HDM对上皮细胞和树突状细胞的影响，但我们发现HDM直接激活巨噬细胞，巨噬细胞是先天免疫系统的核心细胞，在肺部和气道中大量存在。HDM刺激巨噬细胞诱导IFN-γ和几个基因的表达，这些基因是交替激活的巨噬细胞（AAM）的特征，包括几丁质酶家族成员，与过敏性疾病密切相关。因此，我们的总体目标是在这个建议是HDM所利用的先天免疫传感系统，导致一个替代激活状态的巨噬细胞分化的特点。对这一过程的理解在临床上是重要的;人类哮喘患者的血液和气道中AAM数量增加，几丁质酶蛋白量增加，特别是在哮喘急性发作期间。此外，我们已经表明，AAM启动和放大哮喘小鼠模型的症状。 待检验的中心假设是HDM中发现的AAMP阵列激活先天信号传导途径，其协调地导致巨噬细胞中AAM基因的表达，增强过敏和哮喘。旨在检验这些假设的具体目的是：1）确定细胞表面传感器在HDM诱导的反应中的作用，2）确定炎性小体和IL-1家族成员在HDM诱导的效应中的作用，3）分析IFN-γ的作用。对高密度聚乙烯诱导的反应，和4）通过比较从对照或哮喘退伍军人分离的人巨噬细胞中的反应来验证HDM对巨噬细胞的作用。这些实验将通过用HDM刺激从野生型和基因缺陷小鼠制备的巨噬细胞在体外进行。我们还将分析HDM对来源于PBMC的人巨噬细胞的影响。重要的是，一旦我们确定了一个先天传感器和信号通路，这是必要的HDM诱导的巨噬细胞在体外的影响，我们将分析传感器在巨噬细胞活化和过敏性肺部炎症在体内使用HDM诱导哮喘的小鼠模型的重要性。 我们的研究的预期结果是，它将描绘由无处不在的环境过敏原HDM激活的驱动AAM基因表达的信号通路。这种知识的增加将有利于退伍军人和国家，因为这些途径可能会导致确定新的目标，以控制高密度脂蛋白诱导的过敏性鼻炎和哮喘。

DESCRIPTION (provided by applicant): US soldiers who have served in Iraq show an increased risk for allergic rhinitis and asthma. Soldiers deployed in the Persian Gulf had twice the risk of developing allergic rhinitis as compared to homeland stationed personnel and 1.6 times the risk of developing asthma. Furthermore, the diagnosis of asthma with symptoms after the age of 12 years is an exclusion critierion for military enlistment. While the reason for the increased risk for allergic inflammatoy diseases has not been established, exposure to high levels of dust and other inhaled particles is thought to be the most likely explanation. The ubiquitous environmental allergen, house dust mite (HDM), was found in high levels in the tents of soldiers serving in Iraq and is known to be a major inducer of asthma. It has been estimated that between 50-80% of rhinitis and asthma is due to HDM; however, the mechanisms by which HDM induces and exacerbates asthma are not fully understood. HDM and many other inhaled particulates contain stimulatory structures we have termed allergen- associated molecular patterns (AAMPs) that engage and stimulate innate pattern recognition receptors (PRR). While others have studied the effects of HDM on epithelial and dendritic cells, we have found that HDM directly activates macrophages, a cell that is central in the innate immune system and found in abundance in the lungs and airways. HDM stimulates macrophages to induce the expression of IFN-¿ and several genes that are characteristic of alternatively activated macrophages (AAM), including chitinase family members, that are strongly associated with allergic disease. Thus, our overall goal in this proposal is to characterize the innate immune sensing systems utilized by HDM that lead to an alternatively activated state of macrophage differentiation. An understanding of this process is clinically important; human asthmatics have elevated numbers of AAM and increased amounts of chitinase proteins in their blood and airways, especially during asthma exacerbations. Furthermore, we have shown that AAM initiate and amplify the symptoms of asthma in a mouse model. The central hypothesis to be tested is that the array of AAMPs found in HDM activate innate signaling pathways that coordinately lead to the expression of AAM genes in macrophages enhancing allergy and asthma. The specific aims designed to test these hypotheses are 1) to determine the contribution of cell surface sensors in HDM-induced responses, 2) to determine the role of the inflammasome and IL-1 family members in HDM-induced effects, 3) to analyze the contribution of IFN-¿ to the HDM-induced responses, and 4) to validate the effect of HDM on macrophages by comparing responses in human macrophages isolated from controls or asthmatic veterans. These experiments will be performed in vitro by stimulating macrophages prepared from wild type and gene deficient mice with HDM. We will also analyze the effects of HDM on human macrophages derived from PBMC. Importantly, once we identify an innate sensor and signaling pathway that is necessary for HDM-induced effects on macrophages in vitro, we will analyze the importance of the sensor in macrophage activation and allergic lung inflammation in vivo using a mouse model of HDM-induced asthma. The anticipated outcome of our research is that it will delineate the signaling pathways activated by the ubiquitous environmental allergen HDM that drive expression of AAM genes. This increase in knowledge will have benefit for veterans and the nation because these pathways will likely lead to the identification of new targets for the control of HDM-induced allergic rhinitis and asthma.