Immunopathogenesis of Bullous Pemphigoid

描述（由申请方提供）：大疱性类天疱疮（BP）是一种自身免疫性表皮下水疱性疾病，其特征为自身抗体和病变部位的炎性浸润。BP自身抗体识别两种半桥粒蛋白，BP 180和BP 230。体外和体内研究已经证明，抗BP 180 IgG自身抗体固定补体并且是致病的。NC 16 A是BP 180的胞外结构域，是致病性自身抗体的主要靶标。BP患者的疱液和血清中存在升高的促炎细胞因子，包括TNF-α和IL-1 β。然而，这些关键炎症介质的作用以及它们在BP中如何上调仍然未知。缺乏合适的体内系统是使用患者源性自身抗体研究BP中炎症免疫反应的主要障碍。我们的实验室最近产生了人源化BP 180小鼠品系（称为NC 16 A小鼠），其中小鼠BP 180 NC 14 A结构域被人BP 180 NC 16 A结构域取代。注射了抗NC 16 A自身抗体的NC 16 A小鼠出现皮肤病变，其概括了BP的关键免疫组织学特征。我们的初步研究结果表明，病原性抗体诱导的表皮下水疱形成与TNF-α和IL-1 β水平的升高相关并依赖于TNF-α和IL-1 β水平的升高，阻断炎性小体的组装/激活可显著降低炎症反应， IL-1 β水平，并消除随后的水泡。因此，本提案的目的是使用我们的NC 16 A小鼠模型研究炎性小体在BP中的作用。我们对这一建议的中心假设是，炎性小体通过介导IL-1 β的产生和随后的炎性细胞浸润和组织损伤在实验性BP的发展中发挥关键作用。为了确定炎性小体是否参与实验性BP，并揭示炎性小体在表皮下水疱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NC 16 A小鼠实验性BP是否需要炎性小体激活;目的2是确定抗NC 16 A自身抗体介导的炎性小体激活是否发生在肥大细胞中;目的3将确定IL-1 β的炎性体非依赖性激活是否上调并参与NC 16 A小鼠的BP起泡。所提出的研究试图建立炎性小体激活和BP之间的直接联系，这在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尚未建立。由于该提案整合了疾病机制研究和临床前试验，预计这些发现将对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-α and IL-1ß 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-α and IL-1ß, and blocking inflammasome assembly/activation genetically or pharmacologically significantly reduces the IL-1ß 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-1ß 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-1ß 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.