RA synovial fibroblast exosomes(RA-EXo) mediated bone erosion via AhR/TRAF2pathway

风湿性关节炎（RA）在退伍军人中比非退伍军人更普遍。妇女占 军事人员的比例越来越高，关节炎的患病率高于男性。因此，RA是一种高度 退伍军人管理局（VA）的相关问题。在RA滑膜、类风湿关节炎滑膜成纤维细胞中 RASF是过度增殖的，是增生性滑膜组织终末层中的主要细胞类型， 侵入并降解邻近的软骨和骨。TRAF 2介导的NF-κ B B和JNK活化导致 RASF的过度增殖、慢性炎症和作为RA标志的侵蚀性关节炎。如何NF- 类风湿性滑膜成纤维细胞中JNK B和JNK的激活仍然是难以捉摸的，尽管研究已经证明， 阻断TNF α介导的NF-κ B B和JNK的活化可减轻RA的进展。然而，一个大的 RA患者人群对抗TNF α治疗无应答。我们小组和其他人的研究表明 从类风湿性滑膜成纤维细胞（RA-Exo）释放的外泌体有助于RA致病性， 在包括RA在内的几种不同的关节疾病动物模型中，外来体是小细胞衍生的 囊泡大小为30-100 nm，来源于内吞作用。外泌体通过胞吐作用释放到细胞外 空间，在那里它们被认为是细胞间通信的重要驱动因素。滑膜液中的外来体 RA患者可导致炎症、软骨退化和关节破坏。然而， 滑液可由滑膜中包括RASF的不同类型的细胞释放。哪些细胞类型 导致关节炎症和软骨退化的外泌体的释放还没有得到很好的研究。 与该提议特别相关的是，我们已经证明RASF外泌体（RA-Exo）激活TNF-α。 受体相关因子2（TRAF 2）介导的NF-κ B B和JNK途径的激活被以下物质促进： 稳定TRAF 2。更重要的是，我们的初步数据清楚地表明，芳香烃受体， (AhR)在RA患者的滑膜中表达显著升高。表达与 骨侵蚀，并与TRAF 2定位，强烈支持该途径在发病机制中的相关性 RA在人类从机制上讲，AhR在RA-Exo中富集，并且RA-Exo AhR是稳定 TRAF2.我们的总体假设是，在RA-Exo中以AhR为中心的网络导致TRAF 2 降解，以及防止TRAF 2介导的RASF中NF-κ B B和JNK途径的活化。 因此，破坏RA外泌体中的AhR网络将消除/减轻骨侵蚀和炎症 通过影响RA-Exo介导的途径，促进RA滑膜中骨侵蚀的发展， 患者 我们实现这一目标的计划概述在以下三个具体目标中： 1.确定导致小鼠模型中关节炎发展的RA-Exo AhR网络。 2.确定RA-Exo AhR相关激酶活性是否介导TRAF 2AF的解离 来自TRAF 2综合体。 3.确定阻断VCIP 135向RA-Exo AhR的募集是否导致阻止 在huRASF/SCID小鼠模型中侵蚀性关节炎的发展。 本研究的积极成果将为未来的产品开发机制驱动的新产品提供基础 治疗RA的药物此外，它对于从RA-Exo中预测无反应性的生物标志物具有高价值， 在开始抗TNF α或个性化药物治疗之前，

Rheumatoid Arthritis (RA) is more prevalent among veterans than nonveterans. Women comprise an increasing proportion of military personnel and have a higher prevalence of arthritis than men. Thus, RA is a highly relevant problem for the Veterans Administration (VA). In RA synovium, rheumatoid arthritis synovial fibroblasts (RASFs) are hyper proliferated, the leading cell type in the terminal layer of the hyperplastic synovial tissue that invades and degrades adjacent cartilage and bone. TRAF2 mediated activation of NF-B and JNK leads to hyperproliferation of RASFs, chronic inflammation and the erosive arthritis which is the hallmark of RA. How NF- B and JNK is activated in rheumatoid synovial fibroblast remains elusive, though studies have demonstrated that the blockade of TNF mediated activation of NF-B and JNK attenuates the RA progression. However, a large population of RA patients are non-response to anti-TNF therapy. Research from our group and others has shown that exosomes released from rheumatoid synovial fibroblasts (RA-Exo) contribute to RA pathogenicity and inflammation in several different animal models of joint disease, including RA. Exosomes are small cell derived vesicles that are 30-100 nm in size and of endocytic origin. Exosomes released by exocytosis into the extracellular space, where they are considered important drivers of intercellular communication. Exosomes in synovial fluid of RA patients can lead to inflammation, degeneration of cartilage, and destruction of joints. However, exosomes in synovial fluid could be released by different types of cells including RASFs in the synovium. Which cell types release exosomes that contribute to joint inflammation and degeneration of cartilage is not well studied. Of particular relevance to this proposal, we have demonstrated that RASF exosomes (RA-Exo) activate the TNF- receptor-associated factor 2 (TRAF2) mediated activation of the NF-B and JNK pathways is promoted by stabilization of TRAF2. More importantly, our preliminary data clearly demonstrate that aryl hydrocarbon receptor (AhR) expression is significantly elevated in synovium from patients with RA. Expression positively correlates with bone erosion and is localized with TRAF2, strongly supporting the relevance of this pathway in the pathogenesis of RA in humans. Mechanistically, AhR is enriched in the RA-Exo and RA-Exo AhR is required for stabilizing TRAF2. Our OVERALL HYPOTHESIS is that targeting AhR centered networks in RA-Exo leads to TRAF2 degradation, and the prevention of TRAF2 mediated activation of the NF-B and JNK pathways in RASFs. Therefore, disruption of the AhR network in RA exosomes will eliminate/attenuate bone erosion and inflammation by affecting RA-Exo mediated pathways contributing to the development of bone erosion in synovium of RA patients. Our plan to accomplish this objective are outlined in these three specific aims: 1. Identify the RA-Exo AhR network that results in the development of arthritis in the mouse models. 2. Determine whether RA-Exo AhR-associated kinase activity mediates dissociation of TRAF2AF from the TRAF2 complex. 3. Determine whether blocking the recruitment of VCIP135 to RA-Exo AhR results in preventing the development of erosive arthritis in the huRASF/SCID mouse model. The positive outcome of this study for future products would provide a basis for developing mechanism-driven novel drugs for RA therapy. Moreover, it is of high value for predicting biomarkers from RA-Exo of non-responsive individuals prior to commencing anti-TNF or personalized drug therapy.