Regulation of Macrophage Activation by House Dust Mite

曾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 国土安全部派驻人员，患哮喘的风险是后者的1.6倍。此外，诊断出的 12岁以后出现症状的哮喘是入伍的排除标准。而理工学院- 儿子患过敏性炎症性疾病的风险增加尚未确定，暴露于高水平 粉尘和其他吸入颗粒物被认为是最可能的解释。无处不在的环境 过敏原，房屋尘螨(HDM)，被发现在伊拉克服役的士兵的帐篷中含量很高，已知 成为哮喘的主要诱因。据估计，50%-80%的鼻炎和哮喘是由于 HDM。然而，HDM诱发和加重哮喘的机制尚不完全清楚。 HDM和许多其他可吸入颗粒物含有刺激性结构，我们称之为过敏原-AS- 关联分子模式(AAMP)，参与并刺激先天模式识别受体(PRR)。 虽然其他人研究了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(Mφ)--一种在先天免疫系统中居于中心的细胞，在 肺部和呼吸道。人巨噬细胞集落刺激因子刺激MφS诱导干扰素β和几个特征基因的表达。 交替激活的MφS(又称M2 MφS)的特征，包括几丁质酶家族成员。我们认识到- 在诱导干扰素β和控制几丁质酶基因表达的caspase11之间找到了一条新的途径 和Mφ形态，而不诱导高水平的IL-1β或下垂。此外，我们的初步数据 结果表明：(I)HDM刺激TLR4非依赖性Caspase11蛋白和酶活性增加 (2)Caspase11是HDM体外诱导几丁质酶基因表达和最佳干扰素β所必需的； (3)HDM引起Mφ的大小和形状发生显著变化，并引起肌动蛋白动力学的显著变化，{a 伊拉克胜利营的粉尘样本复制了反应；(Iv)HDM刺激蛋白质spe-spe的表达 CIES表明与自噬相关的过程，如LC-3脂化作用，没有降解通量； 观察到类似的HDM引起的人类原代MφS的变化。因此，我们在这次更新提案中的总体目标 目的是研究非规范的caspase11途径控制Mφ表型和M DNA表型的机制。 因此，HDM引起的哮喘。了解这一过程具有重要的临床意义，因为人类哮喘患者 他们的M2数量增加，血液和呼吸道中几丁质酶蛋白的数量也增加- 尤其是在哮喘加重期间。此外，我们还证明了M2启动并放大了符号-- 在一种小鼠模型中发现哮喘。 有待检验的中心假说是，caspase 11途径调节一种亚 M-φS的M2基因集，并通过调节肌动蛋白动力学控制M-φ的形态和迁移 吞噬小体和自噬小体融合，从而增强过敏和哮喘。设计的具体目标 验证这一假说的方法是：1)研究caspase11在调节去甲肾上腺素诱导的M-φ变化中的作用 表型和变态反应性肺部炎症，2)描述caspase11和自噬MA的作用。 3)验证去甲肾上腺素对肌动蛋白动力学和M-φ运动的调节作用 人MφS和MφS的反应比较哮喘患者和对照组的反应。 我们研究的预期结果是，它将描绘出由 普遍存在的环境变应原HDM，驱动M2基因的表达和Mφ的功能。这一增长 知识对退伍军人和国家都有好处，因为这些途径可能会导致 控制HDM引起的变应性鼻炎和哮喘的新靶点。

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.