Immunobiology of Acute Environmental Asthma

描述（由申请人提供）：本U19项目“急性环境哮喘的免疫生物学”的重点是对先天免疫过程在急性环境哮喘中的介导作用进行机制研究。流行病学研究清楚地表明，与空气污染物有关的哮喘加重是哮喘加重的主要原因。内毒素是一种常见的环境污染物，存在于环境颗粒物中，也存在于职业和家庭环境中。高水平的内毒素可诱导中性粒细胞炎症，低水平的内毒素可增强哮喘患者对气道过敏原的反应。我们已经证明，内毒素引起气道单核细胞和巨噬细胞的变化(CD14、CD80、Fc？RI和HLA-DR)，它们与增强对先天或获得性免疫刺激的反应有关。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（上调中性粒细胞炎症和单核细胞功能）和monarch-1（下调对先天激活的反应）。crypyrin是特别有趣的，因为它通过形成基于Caspase-1的炎性体来切割il -1 ？活性IL-1？（下游产生IL-6等介质）和IL-18。此外，crypyrin在病原体相关分子模式受体（包括CD14促进TLR4结合内毒素）或P2X7受体（ATP被越来越多地认为是宿主细胞在非特异性细胞损伤后释放的内源性危险信号）连接后被激活。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的作用进行机制研究（Project 1-J）。Ting PI)，以及NALP-1和嘌呤能受体P2X7的作用（项目2-B）。科勒，PI)在啮齿动物环境哮喘模型中，与一个翻译项目（项目3-D）一起。Peden， PI)旨在确定内毒素和过敏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家族免疫调节因子和P2X7受体在气道中的表达。除了评估先天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。粘膜纤毛清除减少是一个未充分研究的过程，它介导哮喘恶化，是哮喘严重程度增加的一个特征。

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.