PARP-1 in Juvenile Idiopathic Arthritis-associated IL-10 Promoter Polymorphisms

描述(由申请人提供)： 摘要：幼年特发性关节炎(JIA)是儿童最常见的慢性自身免疫性炎症性疾病。IL-10启动子-1082A/-819T/-592A(ATA)启动子型患者产生的IL-10较低，可导致炎症反应过度，导致更严重的关节炎，提示IL-10基因变异与JIA有直接关联。最近，我们发现聚腺苷二磷酸核糖聚合酶1(PARP-1)是一种新的IL-10基因表达的转录抑制因子，它与ATA IL-10启动子基因的结合亲和力增强。因此，我们假设PARP-1介导的抑制IL-10的产生在JIA的发病机制中起重要作用，取消这种抑制可能会导致治疗JIA的有效方法。IL-10是一种由T细胞、B细胞、巨噬细胞和树突状细胞等多种免疫细胞产生的多效性细胞因子。它抑制促炎细胞因子的产生，并抑制促炎细胞因子的作用，如肿瘤坏死因子-a(TNF-a)。PARP-1是一种高度保守的核锌指蛋白，参与DNA修复、染色质解缩和基因表达。我们最近的工作证明，PARP-1与IL-10启动子的结合可以通过-592a序列的多态而增强，并且PARP-1的过度表达导致人巨噬细胞产生IL-10的水平降低。然而，IL-10如何由PARP-1调节的机制细节尚不清楚，必须阐明才能开发基于PARP-1靶向的新疗法。因此，在本项目中，我们将：(1)从分子水平阐明PARP-1调控IL-10基因表达的机制细节。(2)开发能够逆转PARP-1介导的对表达ATA IL-10启动子基因的JIA患者IL-10产生抑制的方法。这项研究将使我们能够确定调控途径中的关键步骤，这些步骤可能被探索为JIA治疗干预的潜在靶点。此外，对抑制JIA患者易感类型血细胞中PARP-1活性的拟议研究可能最终有助于纠正他们IL-10产生缺陷，从而恢复患者自身控制关节炎炎症的免疫能力。 公共卫生相关性： 阐明PARP-1调节IL-10基因表达的分子机制将使我们能够确定调控途径中的关键步骤，这些步骤可能被探索为青少年关节炎治疗干预的潜在靶点。此外，拟议中的研究如何抑制关节炎患者血细胞中的PARP-1活性可能最终有助于纠正他们的IL-10产生缺陷，从而恢复患者自身控制关节炎炎症的免疫能力。

DESCRIPTION (provided by applicant): ABSTRACT: Juvenile idiopathic arthritis (JIA) is the most common chronic autoimmune inflammatory disease in childhood. Lower IL-10 production in patients with the -1082A/-819T/-592A (ATA) IL-10 promoter genotype can lead to excessive inflammatory responses with more severe arthritis, suggesting a direct association of IL-10 gene variants with JIA. Recently, we identified poly(ADP-ribose) polymerase 1 (PARP-1) as a novel transcriptional repressor of IL-10 gene expression with enhanced binding affinity for the ATA IL-10 promoter genotype. Therefore, we hypothesize that PARP-1-mediated suppression of IL-10 production is important for the pathogenesis of JIA, and that removing this suppression could result in effective therapies for treating patients with JIA. IL-10 is a pleiotropic cytokine produced by a variety of immune cells including T cells, B cells, macrophages and dendritic cells. It inhibits the production of proinflammatory cytokines and suppresses the effects of proinflammatory cytokines such as tumor necrosis factor-a (TNF-a). PARP-1 is a highly conserved nuclear zinc- finger protein involved in DNA repair, chromatin decondensation and gene expression. Our recent work has demonstrated that PARP-1 binding to the IL-10 promoter is enhanced by the -592A sequence polymorphism, and that over-expression of PARP-1 results in lower IL-10 production in human macrophages. However, the mechanistic details of how IL-10 is regulated by PARP-1 are unknown, and must be elucidated in order to develop new therapies based on targeting PARP-1. Therefore, in this project, we will: (1) elucidate the mechanistic detail of how PARP-1 regulates IL-10 gene expression at the molecular level. (2) develop methods capable of reversing PARP-1-mediated suppression of IL-10 production in JIA patients expressing the ATA IL-10 promoter genotype. This study will enable us to identify key steps in the regulatory pathway that may be explored as potential targets of therapeutic intervention in JIA. Moreover, the proposed investigation into ways to inhibit PARP-1 activity in JIA patients' blood cells of the susceptible type may eventually help correct their IL-10 production deficit, thus restoring the patients' own immune capacity to control arthritic inflammation. PUBLIC HEALTH RELEVANCE: RELEVANCE Elucidation of the molecular mechanisms whereby PARP-1 regulates IL-10 gene expression will enable us identify key steps in the regulatory pathway that may be explored as potential targets of therapeutic intervention in juvenile arthritis. Moreover, the proposed investigation into ways to inhibit PARP-1 activity in arthritis patients' blood cells may eventually help correct their IL-10 production deficit, thus restoring the patients' own immune capacity to control arthritic inflammation.