Inflammasome function and SJIA

描述（由申请人提供）：全身性幼年特发性关节炎（SJIA）是一种风湿性疾病，其特征为关节炎、登革热、一过性皮疹，有时还伴有其他类型的全身性炎症。SJIA目前被认为是一种多基因的自身炎症性疾病，但其发病机制的分子细节仍然未知。SJIA的一个显著特征是与巨噬细胞活化综合征（MAS）相关，这是一种可能致命的并发症。这一临床方面，以及SJIA免疫表型研究的数据，指出单核细胞谱系在疾病发病机制中是重要的。活化的单核细胞表达炎性体的组分，炎性体是一种多蛋白复合物，其感知感染性或有害刺激并激活半胱天冬酶-1，导致IL-1 β和IL-18的成熟和分泌，有时导致宿主细胞死亡。基于我们的初步数据，我们假设来自SJIA患者的单核细胞在炎性体途径中具有缺陷。这项R21提案的目的是发现影响单核细胞成熟和释放IL-1 β的宿主途径和基因，并将其作为候选疾病相关因子进行测试。在目标1中，我们将采用一种候选方法，通过测量与SJIA患者细胞中IL-1 β分泌相关的已知分子事件，与年龄匹配的免疫正常儿童细胞进行比较，来表征SJIA单核细胞中可能的缺陷。具体而言，我们将测量细胞因子释放，半胱天冬酶-1活化，半胱天冬酶-1调节的细胞死亡，Rab 39 a，嘌呤能受体P2 X7 R和孔形成蛋白，泛连接蛋白-1的表达水平。将对35例SJIA患者的相关候选基因进行测序。在目标2中，我们将采取一种偏差较小的方法，并进行正向遗传筛选，以确定影响正常细胞中IL-1 β分泌的宿主因素。该筛选可能会提供可能影响SJIA中IL-1 β生物学的其他候选因素。我们的研究结果将描述调节IL-1加工和分泌的分子组分，并最终可能导致新的和创新的方法来预防和治疗SJIA和其他自身炎症性疾病。

DESCRIPTION (provided by applicant): Systemic juvenile idiopathic arthritis (SJIA) is a rheumatic condition characterized by arthritis, quotidian fever, evanescent rash, and sometimes other types of systemic inflammation. SJIA is currently thought to be a multigenic, autoinflammatory disease, but the molecular details of its pathogenesis are still unknown. A striking feature of SJIA is its association with macrophage activation syndrome (MAS), a complication that can be fatal. This clinical aspect, together with data from immunophenotypic studies of SJIA, points to the monocyte lineage as being important in disease pathogenesis. Activated monocytes express components of the inflammasome, a multiprotein complex that senses infectious or noxious stimuli and activates caspase-1, leading to maturation and secretion of IL-1beta and IL-18 and sometimes to host cell death IL-1beta and IL-18 have been implicated in SJIA. Based on our preliminary data, we hypothesize that monocytes from SJIA patients harbor a defect in the inflammasome pathway. The objective of this R21 proposal is to discover host pathways and genes that influence IL- 1beta maturation and release by monocytes and to test these as candidate disease associated factors. In Aim 1, we will take a candidate approach to characterize possible defects in SJIA monocytes by measuring known molecular events related to IL-1beta secretion in cells from SJIA patients compared to cells from age-matched immunologically normal children. Specifically, we will measure cytokine release, activation of caspase-1, caspase-1 regulated cell death, levels of expression of Rab 39a, the purinergic receptor P2X7R, and the pore-forming protein, pannexin-1. Findings will be followed up with sequencing of associated candidate genes in 35 SJIA patients. In Aim 2, we will take a less biased approach and conduct a forward genetic screen to identify host factors that influence IL-1beta secretion in normal cells. This screen will likely provide additional candidate factors potentially affecting IL-1beta biology in SJIA. Our results will delineate molecular components regulating IL-1 processing and secretion and, ultimately, could result in new and innovative approaches to the prevention and treatment of SJIA and other autoinflammatory diseases.