Interaction with Rip2 and Th17 in Chronic Inflammation

 描述（由申请方提供）：Th 17细胞通过募集中性粒细胞提供针对某些但非全部细菌感染的保护性免疫。受体相互作用蛋白2（Rip 2）是细胞内肽聚糖传感器Nod 1和Nod 2使用的衔接分子，在指导针对各种细菌的先天免疫应答中起着重要作用（1）。然而，Th 17细胞产生细胞因子IL-17 A、IL-17 F和IL-22，这些细胞因子与皮肤的慢性炎性疾病（即，牛皮癣），肺（即，哮喘和 慢性阻塞性肺病），和肠（即，克罗恩病）。我们研究了重要的人类病原体肺炎衣原体（CP），它与慢性疾病如过敏性哮喘，慢性肺部疾病，慢性阻塞性肺疾病的恶化以及其他慢性炎症性疾病如动脉粥样硬化和吸烟者肺癌的进展有关。我们之前发现肺泡巨噬细胞中的Rip 2在控制小鼠CP感染中起着关键作用，但存活的Rip 2-/-小鼠发生了严重的慢性肺部炎症，包括增强的肺纤维化（2）。出乎意料的是，我们发现Rip 2缺陷型T细胞本质上倾向于Th 17和IL-17 A的产生，揭示了Rip 2在调节Th 17分化中的新作用。我们的初步研究表明，在致病性（IL-1 β驱动的）Th 17分化的条件下， Rip 2-/- T细胞表现出Th 17分化增强和视黄酸相关孤儿受体α（RORα）表达增加，ROR α是一种重要的转录因子，有助于Th 17偏斜。我们的数据还支持这样的假设，即CP感染后Rip 2-/-小鼠中观察到的慢性炎症是Rip 2-/- T细胞中固有的Th 17偏斜缺陷的结果，与IL-17对细菌杀伤的作用无关。鉴于NOD/Rip 2多态性与人类各种IL-17驱动的慢性炎症性疾病（包括严重哮喘和克罗恩病）相关的鉴定越来越多，我们将寻求确定这种新型Rip 2-Th 17调节轴在T细胞中的功能意义。基于这些关键的新发现，我们提出了以下研究，重点围绕中心假设，即T细胞中的Rip 2缺陷本质上增强了Th 17分化，从而在CP感染期间诱导慢性炎症，并且NODs/RIP 2的缺失通过增强RORα活性增加了Th 17偏斜。为了验证这些假设，我们提出了以下三个具体目标：目标1。确定IL- 17信号在CP感染和慢性肺部炎症和纤维化中的作用。目标2.确定Rip 2/IL-17轴在CP感染诱导的慢性肺部炎症/肺纤维化中的作用，以及人Rip 2 SNP在Th 17驱动疾病中Th 17偏移中的作用。目标3：研究Rip 2调控Th 17细胞分化的分子机制。在这些研究的结论中，我们期望在T细胞中描绘出这种新的Th 17调节途径，并确定了治疗缓解Th 17介导的慢性炎症性疾病的关键靶点。

 DESCRIPTION (provided by applicant): Th17 cells provide protective immunity against certain, but not all, bacterial infections through the recruitment of neutrophils. Receptor interacting protein 2 (Rip2), the adapter molecule used by the intracellular peptidoglycan sensors Nod1 and Nod2, plays an important role in directing innate immune responses against various bacteria (1). However, Th17 cells produce the cytokines IL-17A, IL-17F, and IL-22 that have been linked to chronic inflammatory diseases of skin (i.e., psoriasis), lung (i.e., asthma and chronic obstructive pulmonary disease), and gut (i.e., Crohn's disease). We study the important human pathogen, Chlamydia pneumoniae (CP) that has been associated with chronic conditions such as allergic asthma, chronic lung diseases, exacerbation of chronic obstructive pulmonary disease, and as well as the progression of other chronic inflammatory diseases such as atherosclerosis and lung cancer in smokers. We previously found that Rip2 in alveolar macrophages played a critical role in controlling CP infection in mice, yet surviving Rip2-/- mice developed a profound chronic lung inflammation including enhanced lung fibrosis (2). Unexpectedly, we found that Rip2-deficient T cells were intrinsically skewed towards Th17 and IL-17A production, revealing a novel role for Rip2 in regulating Th17 differentiation. Our preliminary studies show that under conditions of pathogenic (IL-1-driven) Th17 differentiation, Rip2-/- T cells exhibit enhanced Th17 differentiation and increased expression of retinoic acid-related orphan receptor alpha (RORα), an important transcription factor that contributes to Th17 skewing. Our data also support the hypothesis that the chronic inflammation seen in Rip2-/- mice after CP infection is a result of the intrinsic Th17 skewing defect in Rip2-/- T cells, independent of IL-17 effects on bacterial killing. Given the increasing identification of NOD/Rip2 polymorphisms associated with various IL-17-driven chronic inflammatory diseases in humans, including severe asthma and Crohn's disease, we will seek to determine the functional implications of this novel Rip2-Th17 regulatory axis in T cells. Based upon these key novel findings, we propose the following studies focused around the central hypothesis that Rip2 deficiency in T cells intrinsically enhances Th17 differentiation, thereby inducing chronic inflammation during CP infection, and that deletion of NODs/RIP2 increases Th17 skewing through enhanced RORα activity. To test these hypotheses, we propose the following three Specific Aims: Aim 1. To determine the role of IL- 17 signaling during CP infection and chronic lung inflammation and fibrosis. Aim 2. To determine the role of the Rip2/IL-17 axis in CP infection-induced chronic lung inflammation/lung fibrosis and the role of human Rip2 SNPs in Th17 skewing in Th17-driven disease. Aim 3. To investigate the molecular mechanisms by which Rip2 regulates Th17 differentiation. At the conclusion of these studies, we expect to have delineated this novel Th17 regulatory pathway in T cells and have identified key targets for therapeutically mitigating Th17-mediated chronic inflammatory diseases.