Immunobiology of Acute Environmental Asthma

描述（由申请人提供）：U19项目“急性环境性哮喘的免疫生物学”的重点是对先天免疫过程在急性环境性哮喘介导中的作用进行机制研究。流行病学研究清楚地表明，与空气污染物相关的哮喘急性发作是哮喘急性发作的主要原因。内毒素是一种常见的环境污染物，存在于环境颗粒物以及职业和家庭环境中。内毒素在高水平时可引起哮喘患者的嗜肺炎症反应，在低水平时可增强哮喘患者对气道变应原刺激的反应。我们已经表明，内毒素引起气道单核细胞和巨噬细胞的变化（增加CD 14，CD 80，Fc？RI和HLA-DR），其与对先天性或获得性免疫刺激的增强应答相关。我们的团队最近在CATERPILLER家族中发现了新的炎症调节分子，特别是cryopyrin（上调嗜中性炎症和单核细胞功能）和monarch-1（下调对先天激活的反应）。Cryopyrin是特别感兴趣的，因为它通过形成基于Caspase-1的炎性体来切割pro-IL-1？活性IL-1？(with IL-6和其它介质的下游产生）和IL-18。此外，在病原体相关的分子模式受体（包括CD 14通过TLR 4促进的内毒素结合）或P2 X7受体通过ATP（其越来越多地被认为是在非特异性细胞损伤后由宿主细胞释放的内源性危险信号）连接后，冷比林被激活。这些双重激活途径可能解释了各种吸入环境污染物的类似作用，并代表了急性哮喘治疗的新靶点。我们将对CATERPILLER家族成员cryopyrin和monarch-1的作用（项目1-J. Ting PI）以及NALP-1和嘌呤能受体P2 X7的作用（项目2-B）进行机制研究。Koller，PI）在啮齿类动物模型的环境哮喘，结合转化项目（项目3-D。Peden，PI），旨在确定内毒素和变应原诱导的炎症相互作用对过敏性哮喘患者气道生物学的影响。人体研究将集中在气道单核细胞的生物学和先天免疫和CATERPILLAR家族的免疫调节剂和P2 X7受体在气道中的表达。除了评估先天性免疫过程在调节气道炎症中的作用外，我们还将研究这种炎症与气道生理学的关系，特别是粘膜纤毛清除。粘膜纤毛清除率降低是一个未充分研究的过程，它介导哮喘急性发作，是哮喘严重程度增加的一个特征。 项目1：哮喘中的新型和先天免疫基因（TING，J） 项目1描述（由申请人提供）：我们最近发现CATERPILLER家族与构成植物免疫系统的抗病（R）蛋白的NB-LRR（核苷酸结合，富含亮氨酸重复序列）超家族具有结构相似性。在动物界，这个家族也被称为NOD或NLR。这个家族的临床重要性是由家族成员与许多免疫疾病的遗传联系所强调的。在人类基因家族成员中，其中几个似乎在控制过度热情的炎症反应中介导负调控功能。最值得注意的是Monarch-1蛋白，它阻断了NF-？B诱导激酶（NIK）。抑制NIK可降低一系列与哮喘相关的趋化因子的表达。轻度哮喘个体诱导痰的基因分析表明，Monarch-1基因在这些个体中相对于对照组减少，支持该基因在炎症过程中的抑制作用。另一组家族成员调节IL-1的产生。其中最值得注意的是cryopyrin，其在用许多诱导剂刺激时介导炎性小体复合物的形成。炎性体复合物是半胱天冬酶1原加工成成熟半胱天冬酶1所需的。反过来，半胱天冬酶-1是将IL-1原和IL-18原加工成其成熟形式所必需的。IL-1和IL-18分别在炎症和TH 2偏移中起重要作用。Cryopyrin在介导加重炎症的巨噬细胞坏死中也是重要的。因此，有令人信服的理由相信Monarch-1和cryopyrin在哮喘中具有关键作用，但没有体内数据表明情况确实如此。此外，我们已经证明这两种蛋白质都是ATP结合蛋白，并且它们表现出ATP酶活性，从而提供了调节其功能的方法，这可能是药物发现的重要线索。本研究的目的是：（1）研究Monarch-1在三种哮喘动物模型（卵清蛋白诱导的、内毒素诱导的和屋尘螨诱导的）中的相关性，并描述Monarch-1在体内和离体的生化作用。(2)目的：研究冷吡啉及其受体（ASC）与哮喘的相关性。(3)研究并鉴定调节Monarch-1和cryopyrin核苷酸结合特性和ATP酶功能的因素。

DESCRIPTION (provided by applicant): The focus of this U19 project, "Immunobiology of Acute Environmental Asthma", is to conduct mechanistic studies of the role of innate immune processes in mediation of acute environmental asthma. Epidemiological studies have clearly shown that asthma exacerbation linked to air pollutants is a major cause of asthma exacerbation. Endotoxin is a commonly encountered environmental pollutant found in ambient particulate matter and in occupational and domestic settings as well. Endotoxin can induce neutrophilic inflammation at high levels, and at low levels enhance response of asthmatics to airway allergen challenge. We have shown that endotoxin causes changes in airway monocytes and macrophages (increased CD14, CD80, Fc?RI and HLA-DR) which are associated with enhanced response to either innate or acquired immune stimuli. Our team has recently identified novel regulatory molecules of inflammation in the CATERPILLER family, specifically cryopyrin (which upregulates neutrophilic inflammation and monocytic function) and monarch-1, (which downregulates response to innate activation). Cryopyrin is of particular interest as it acts through formation of a Caspase-1 based inflammasome to cleave pro-IL-l? to active IL-1? (with downstream production of IL-6 and other mediators) and IL-18. Furthermore, cryopyrin is activated after ligation of either pathogen associated molecular pattern receptors (including CD14 facilitated binding of endotoxin by TLR4) or the P2X7 receptor by ATP (which is increasingly recognized as an endogenous danger signal released by host cells following non-specific cell injury). These dual activation pathways likely account for the similar actions of a wide variety of inhaled environmental contaminants, and represent novel targets for treatment of acute asthma. We will conduct mechanistic studies of the role of the CATERPILLER family members cryopyrin and monarch-1 (Project 1-J. Ting PI), and the role of NALP-1 and the purinergic receptor P2X7 (Project 2-B. Koller, PI) in rodent models of environmental asthma, in conjunction with a translational project (Project 3-D. Peden, PI) designed to determine the effect of interaction of endotoxin- and allergen-induced inflammation on the airway biology of allergic asthmatics. Human studies will be focused on the biology of airway monocytic cells and the expression of innate immune and the CATERPILLAR family of immune regulators and P2X7 receptors in the airway. In addition to assessment of the role of innate immune processes in regulating airway inflammation, we will examine the relationship of this inflammation on airway physiology, specifically mucociliary clearance. Decreased mucociliary clearance is an understudied process which mediates asthma exacerbation and is a feature of increased asthma severity. PROJECT 1: Novel and innate immune genes in asthma (TING, J) PROJECT 1 DESCRIPTION (provided by applicant): We recently discovered the CATERPILLER family which share structural similarities with the NB-LRR (nucleotide-binding, leucine-rich repeat) super-family of disease resistance (R) proteins that constitutes the plant immune system. In the animal kingdom, this family is also known as NOD or NLR. The clinical importance of this family is underscored by the genetic linkage of family members to a number of immunologic disorders. Among the human gene family members, several of these appear to mediate negative regulatory function in controlling an overzealous inflammatory response. Most notable is the Monarch-1 protein which blocks the function of NF-?B inducing kinase (NIK). Inhibition of NIK reduces the expression of an array of chemokines with relevance in asthma. Gene profiling of induced sputum from mildly asthmatic individuals suggests that the Monarch-1 gene is reduced in these individuals relative to controls, supporting the inhibitory role of this gene during inflammation. Another group of family members regulates IL-1 production. Most notable among these is cryopyrin which mediates formation of the inflammasome complex upon stimulation with a number of inducers. The inflammasome complex is required for procaspase 1 processing to mature caspase 1. In turn, caspase-1 is required for the processing of pro-IL-1 and pro-IL-18 to their mature forms. IL-1 and IL-18 are respectively important in inflammation and TH2 skewing. Cryopyrin is also important in mediating macrophage necrosis which exacerbates inflammation. Thus there are compelling reasons to believe that Monarch-1 and cryopyrin have crucial roles in asthma, however there is no in vivo data to indicate that this is the case. Furthermore we have shown that both of these proteins are ATP-binding proteins, and they exhibit ATPase activity, thus providing ways to modulate their function, which might be important leads to drug discovery. The goals of this proposal are: (1) To study the relevance of Monarch-1 in three animal models of asthma (OVA-induced, endotoxin, and house dust mite and delineate the biochemical effects of Monarch-1 in vivo and ex vivo. (2) To study the relevance of cryopyrin and a cryopyrin-adaptor (ASC) in asthma. (3) To study and identify factors which modulate the nucleotide-binding properties and ATPase function of Monarch-1 and cryopyrin.