Immunopathogenesis of Bullous Pemphigoid

描述(申请人提供)：大疱性类天疱疮(BP)是一种自身免疫性真皮下水泡病，其特征是皮损部位有自身抗体和炎性浸润物。BP自身抗体识别两种半染色体蛋白，BP180和BP230。体内外研究表明，抗BP180自身抗体可结合补体，具有致病性。NC16A是BP180的胞外区，是致病自身抗体的主要靶点。包括肿瘤坏死因子在内的促炎细胞因子升高？那么IL-1呢？存在于BP患者的疱液和血清中。然而，这些关键的炎症介质的作用以及它们在BP中是如何上调的仍不清楚。缺乏合适的体内系统是使用患者来源的自身抗体研究BP炎性免疫反应的主要障碍。我们的实验室最近培育了一个人源化的BP180小鼠品系(命名为NC16A小鼠)，其中小鼠的BP180NC14A结构域被人的BP180NC16A结构域取代。注射抗NC16A自身抗体的NC16A小鼠会出现皮肤损害，这些损害概括了BP的关键免疫组织学特征。我们的初步结果表明，致病抗体诱导的真皮下水泡的形成与肿瘤坏死因子？和IL-1？，从基因或药物上阻断炎性小体组装/激活可显著降低IL-1？并消除随后的水泡。因此，这项建议的目的是利用我们的NC16A小鼠模型研究炎性小体在BP中的作用。我们对这一提议的中心假设是，炎性小体通过介导IL-1？产生并随之而来的炎症细胞浸润和组织损伤。为了确定炎性小体是否参与实验性BP，并揭示炎性小体在真皮下水泡形成过程中的确切功能，我们提出了以下具体目标：目的1是确定NC16A小鼠实验性BP是否需要炎性小体激活；目的2是确定抗NC16A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是否非炎性小体激活？是上调的，并参与了NC16A小鼠的BP水泡。拟议的研究试图在炎症体激活和BP之间建立直接联系，这一作用在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确定。由于这项建议整合了疾病机制研究和临床前试验，预计研究结果将对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-? 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.