Regulation of Macrophage Activation by House Dust Mite

在伊拉克服役的美国士兵患过敏性鼻炎的风险增加， 哮喘;部署在波斯湾的士兵患过敏性鼻炎的风险是部署在海湾的士兵的两倍。 美国国土安全部派驻人员和1.6倍的风险发展为哮喘。此外，诊断 12岁以后出现哮喘症状是入伍的排除标准。而真正的-- 儿子的过敏性炎症性疾病的风险增加尚未建立，接触高水平 灰尘和其他吸入颗粒被认为是最有可能的解释。无处不在的环境 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， 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不完全清楚。 HDM和许多其他吸入颗粒物含有刺激性结构，我们称之为过敏原， 结合和刺激先天模式识别受体（PRR）的相关分子模式（AAMP）。 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直接影响上皮细胞和树突状细胞。 激活巨噬细胞（M φ）-一种在先天免疫系统中处于中心位置的细胞， 肺部和呼吸道HDM刺激M φ诱导IFN β和几个特征性基因的表达， 具有交替激活的M φ（也称为M2 M φ）的特征，包括几丁质酶家族成员。我们发现- 阐明了IFN β诱导和控制几丁质酶基因表达的caspase 11之间的新途径 和M φ形态而不诱导高水平的IL-1 β或焦亡。此外，我们的初步数据显示， 表明：（i）HDM刺激非TLR4依赖性caspase 11蛋白和酶活性的增加， （ii）caspase 11是HDM体外诱导几丁质酶基因表达和IFN β最适表达所必需的; (iii)HDM诱导M φ的大小和形状发生显著变化，同时肌动蛋白动力学发生显著变化，{a 响应复制的灰尘样品从胜利营，伊拉克;（iv）HDM刺激蛋白质spe-的表达， 指示自噬相关过程的片段，例如LC-3脂化，而没有降解通量;和（v）我们 在人类原发性M φ中观察到类似的HDM诱导的变化。因此，我们在这项更新建议中的总体目标 是表征非经典半胱天冬酶11途径控制M φ表型的机制， 从而导致高密度脂蛋白引起的哮喘。了解这一过程在临床上是重要的，因为人类哮喘患者 血液和呼吸道中的M2数量增加，几丁质酶蛋白量增加， 尤其是在哮喘恶化期间。此外，我们已经表明，M2启动和放大的symp- 小鼠哮喘模型的研究。 有待检验的中心假设是caspase 11途径调节一个亚单位的表达， M φ中的一组M2基因，并通过调节肌动蛋白动力学来控制M φ的形态和迁移， 吞噬体和自噬体融合，从而增强过敏和哮喘。设计的具体目标 为了验证这一假设，我们采用了以下方法：1）研究caspase 11在HDM诱导的M φ变化中的作用 表型和过敏性肺部炎症，2）描绘caspase 11和自噬性肿瘤的贡献， 3）证实HDM诱导的肌动蛋白动力学和M φ运动的调节， 人M φ的反应和{比较哮喘患者和对照受试者的M φ反应。} 我们研究的预期结果是，它将描绘出由蛋白质激活的信号通路。 普遍存在的环境过敏原HDM驱动M2基因表达和M φ功能。的这种增加 知识将有利于退伍军人和国家，因为这些途径可能会导致识别， 阳离子的新目标，用于控制高密度脂蛋白诱导的过敏性鼻炎和哮喘。

United States (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 criterion for military enlistment. While the rea- son for the increased risk for allergic inflammatory 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-as- sociated 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 the macrophage (Mφ) - a cell that is central in the innate immune system and found in abundance in the lungs and airways. HDM stimulates Mφs to induce the expression of IFNβ and several genes that are char- acteristic of alternatively-activated Mφs (also termed M2 Mφs), including chitinase family members. We identi- fied a novel pathway between the induction of IFNβ and caspase 11 that controls chitinase gene expression and Mφ morphology without inducing high levels of IL-1β or pyroptosis. Furthermore, our preliminary data show that: (i) HDM stimulates an increase in caspase 11 protein and enzyme activity in a TLR4-independent manner; (ii) caspase 11 is required for chitinase gene expression and optimal IFNβ induced by HDM in vitro; (iii) HDM induces a dramatic change in Mφ size and shape with pronounced changes in actin dynamics, {a response replicated by dust samples from Camp Victory, Iraq; (iv) HDM stimulates expression of protein spe- cies indicative of autophagy-related processes, such as LC-3 lipidation, without degradative flux;} and (v) we observed similar HDM-induced changes in human primary Mφs. Thus, our overall goal in this renewal proposal is to characterize the mechanism by which the non-canonical caspase 11 pathway controls Mφ phenotype and thus HDM-induced asthma. An understanding of this process is clinically important since human asthmatics have elevated numbers of M2, as well as increased amounts of chitinase proteins in their blood and airways- especially during asthma exacerbations. Furthermore, we have shown that M2 initiate and amplify the symp- toms of asthma in a mouse model. The central hypothesis to be tested is that the caspase 11 pathway regulates the expression of a sub- set of M2 genes in Mφs and controls Mφ morphology and migration by regulating actin dynamics critical for phagolysome and autophagosome fusion, thereby enhancing allergy and asthma. The specific aims designed to test this hypothesis are: 1) to characterize the role of caspase 11 in regulating HDM-induced changes in Mφ phenotype and allergic lung inflammation, 2) to delineate the contribution of caspase 11 and autophagic ma- chinery to the regulation of actin dynamics and Mφ motility induced by HDM, and 3) to validate HDM-induced responses in human Mφs and {compare responses in Mφs from from asthmatics and control subjects.} 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 M2 genes and Mφ function. This increase in knowledge will have benefit for Veterans and the nation because these pathways will likely lead to the identifi- cation of new targets for the control of HDM-induced allergic rhinitis and asthma.