Immunopathogenesis of Bullous Pemphigoid

描述（由申请人提供）：大疱性类天疱疮（BP）是一种自身免疫性表皮下起泡性疾病，以自身抗体和病变部位的炎症浸润为特征。BP自身抗体识别两种半粒染色体蛋白，BP180和BP230。体外和体内研究表明，抗bp180 IgG自身抗体可固定补体并具有致病性。NC16A是BP180的胞外结构域，是致病性自身抗体的主要靶点。促炎细胞因子升高，包括TNF-？和il - 1 ?存在于BP患者的水疱液和血清中。然而，这些关键炎症介质的作用以及它们如何在BP中上调仍不清楚。缺乏合适的体内系统是使用患者源性自身抗体研究BP炎症免疫反应的主要障碍。我们的实验室最近培育了一种人源化BP180小鼠品系（称为NC16A小鼠），其中小鼠BP180NC14A结构域被人类BP180NC16A结构域所取代。注射抗NC16A自身抗体的NC16A小鼠出现皮肤病变，再现了BP的关键免疫组织学特征。我们的初步结果显示，病原抗体诱导的表皮下水疱形成与TNF-？和il - 1 ?阻断炎性小体的组装/激活，从基因或药理学上显著降低IL-1？水平和消除随后的起泡。因此，本提案的目的是利用NC16A小鼠模型研究炎症小体在BP中的作用。我们的中心假设是炎症小体通过介导IL-1在实验性BP的发展中起关键作用。炎症细胞的产生及随后的浸润和组织损伤。为了确定炎症小体是否参与实验性BP，揭示炎症小体在表皮下起泡形成过程中的确切功能，我们提出以下具体目的：目的1是确定NC16A小鼠的实验性BP是否需要炎症小体激活；目的2是确定抗nc16a自身抗体介导的炎性体激活是否发生在肥大细胞中；Aim 3将确定是否炎性小体独立激活IL-1？表达上调并参与NC16A小鼠的BP起泡。拟议的研究试图建立炎症小体活化与BP之间的直接联系，这一作用尚未在BP和任何其他自身免疫性疾病，特别是自身抗体介导的疾病中建立。由于本提案将疾病机制研究和临床前试验相结合，研究结果有望对BP患者的治疗产生重大影响。

DESCRIPTION (provided by applicant): Bullous pemphigoid (BP) is an autoimmune subepidermal blistering disease characterized by autoantibodies and an inflammatory infiltrate at the lesional site. BP autoantibodies recognize two hemidesmosomal proteins, BP180 and BP230. In vitro and in vivo studies have demonstrated that anti-BP180 IgG autoantibodies fix complement and are pathogenic. NC16A, an extracellular domain of BP180, is the primary target of pathogenic autoantibodies. Elevated proinflammatory cytokines including TNF-? and IL-1? are present in blister fluids and sera of BP patients. However, the roles of these critical inflammatory mediators and how they are up-regulated in BP remain unknown. Lack of a suitable in vivo system is a major obstacle for studies of inflammatory immune responses in BP using patient-derived autoantibodies. Our lab recently generated a humanized BP180 mouse strain (termed NC16A mice), in which the mouse BP180NC14A domain is replaced by the human BP180NC16A domain. The NC16A mice injected with anti-NC16A autoantibodies develop skin lesions that recapitulate key immunohistological features of BP. Our preliminary results showed that subepidermal blister formation induced by pathogenic antibodies is associated with and dependent on increased levels of TNF-? and IL-1?, and blocking inflammasome assembly/activation genetically or pharmacologically significantly reduces the IL-1? level and abolishes subsequent blistering. Therefore, the objective of this proposal is to study the role of inflammasomes in BP using our NC16A mouse model. Our central hypothesis for this proposal is that inflammasomes play a critical role in the development of experimental BP by mediating IL-1? generation and subsequent inflammatory cell infiltration and tissue injury. To determine whether inflammasomes are involved in experimental BP and to uncover the precise functions of inflammasomes during the subepidermal blistering formation, we propose the following Specific Aims: Aim 1 is to determine whether inflammasome activation is required for experimental BP in NC16A mice; Aim 2 is to determine whether anti-NC16A autoantibody-mediated inflammasome activation takes place in mast cells; Aim 3 will determine whether inflammasome-independent activation of IL-1? is up-regulated and involved in BP blistering in NC16A mice. The proposed studies seek to establish a direct link between the inflammasome activation and BP, a role which has not been established in BP and any other autoimmune, especially autoantibody-mediated diseases. Since this proposal integrates both disease mechanism studies and preclinical trials, the findings are expected to have a significant impact on the treatment of patients with BP.