Immunobiology of Acute Environmental Asthma

描述(申请人提供)：这个U19项目的重点是“急性环境性哮喘的免疫生物学”，是对天然免疫过程在急性环境性哮喘中的调节作用进行机制研究。流行病学研究清楚地表明，与空气污染物有关的哮喘恶化是哮喘恶化的主要原因。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。内毒素在高水平可诱导中性粒细胞炎症，在低水平可增强哮喘患者对呼吸道变应原攻击的反应。我们已经证明内毒素可引起呼吸道单核细胞和巨噬细胞的改变(CD14、CD80、Fc？RI和HLA-DR增加)，这与对先天或获得性免疫刺激的增强反应有关。我们的团队最近在卡特彼勒家族中发现了新的炎症调节分子，特别是低温比林(上调中性粒细胞炎症和单核细胞功能)和Monch-1(下调对先天激活的反应)。通过形成基于Caspase-1的炎性小体来裂解前IL-L，低温比林是特别有趣的。去激活IL-1？(下游产生IL-6和其他介质)和IL-18。此外，无论是与病原体相关的分子模式受体(包括CD14促进TLR4与内毒素的结合)或P2X7受体(日益被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，低温比林都被激活。这些双重激活途径可能解释了各种吸入环境污染物的相似作用，并代表了治疗急性哮喘的新靶点。我们将对卡特彼勒家族成员低温比林和君主-1的作用进行机制研究(项目1-J。Ting Pi)以及NALP-1和嘌呤能受体P2X7的作用(方案2-B)。Koller，Pi)在环境哮喘的啮齿动物模型中，与一个翻译项目(项目3-D)相结合。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呼吸道生物学的影响。人类研究将集中在呼吸道单核细胞的生物学和先天免疫的表达，以及卡特彼勒免疫调节剂家族和呼吸道中的P2X7受体。除了评估先天免疫过程在调节呼吸道炎症中的作用外，我们还将研究这种炎症与呼吸道生理的关系，特别是粘液纤毛清除。粘液纤毛清除减少是一个未被充分研究的过程，它介导了哮喘的恶化，是哮喘严重程度增加的一个特征。 项目1：哮喘中的新的和先天免疫基因(Ting，J) 项目1描述(申请人提供)：我们最近发现了卡特彼勒家族，它与构成植物免疫系统的抗病(R)超家族蛋白NB-LRR(核苷酸结合，富含亮氨酸的重复)在结构上有相似之处。在动物界，这个家庭也被称为NOD或NLR。这个家族的临床重要性被家族成员与一些免疫疾病的遗传联系所强调。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方面起到了负调节作用。最值得注意的是Monch-1蛋白，它阻断了核因子-B诱导激酶(NIK)的功能。抑制NIK可减少一系列与哮喘相关的趋化因子的表达。对轻度哮喘患者诱导痰的基因图谱表明，与对照组相比，这些患者的Monch-1基因减少，支持该基因在炎症过程中的抑制作用。另一组家庭成员负责调节IL-1的产生。其中最值得注意的是低温比林，它在一些诱导剂的刺激下介导炎性小体复合体的形成。炎症体复合体是原天冬氨酸蛋白酶1加工成熟caspase 1所必需的，而caspase-1又需要caspase-1将前白介素1和前白介素18加工成成熟形式。IL-1和IL-18分别在炎症和TH2偏斜中起重要作用。低温比林在介导巨噬细胞坏死方面也很重要，巨噬细胞坏死会加剧炎症。因此，有令人信服的理由相信君主-1和低温比林在哮喘中起着关键作用，然而，没有体内数据表明这是真的。此外，我们还发现这两种蛋白都是三磷酸腺苷结合蛋白，它们都具有ATPase活性，从而提供了调节其功能的途径，这可能是药物发现的重要线索。本研究的目的是：(1)研究Monch-1在三种哮喘动物模型(卵清蛋白诱导、内毒素诱导和屋尘螨诱导)中的相关性，并描述其在体内和体外的生化作用。(2)探讨低温比林及其受体(ASC)在哮喘发病中的作用。(3)研究和鉴定影响Monch-1和Cryopyrin核苷酸结合特性和ATPase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.