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

类风湿性关节炎(RA)在退伍军人中比非退伍军人更常见。女性构成了 军人的比例越来越高，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。RA滑膜中的类风湿关节炎滑膜成纤维细胞 (RASF)是过度增殖的，是增生性滑膜组织终末层的主要细胞类型， 侵袭并降解邻近的软骨和骨骼。TRAF2介导的NF-B和JNK的激活导致 RASF的过度增殖、慢性炎症和侵蚀性关节炎是RA的标志。核因子是如何- B和JNK在类风湿滑膜成纤维细胞中被激活仍然难以捉摸，尽管研究表明 阻断肿瘤坏死因子介导的NF-B和JNK的激活可延缓RA的进展。然而，一个很大的 RA患者对抗肿瘤坏死因子治疗无反应。我们小组和其他人的研究表明 类风湿滑膜成纤维细胞(RA-Exo)释放的外切体参与RA的致病作用 几种不同关节疾病动物模型的炎症反应，包括类风湿关节炎。外切体是小细胞衍生的 大小为30-100 nm的内吞来源的小泡。胞吐作用释放的胞外体进入细胞外 在太空中，它们被认为是细胞间通信的重要驱动力。关节滑液中的外周小体 类风湿关节炎患者可导致炎症、软骨退化和关节破坏。然而，Exosome in 滑液可由不同类型的细胞释放，包括滑膜中的RASF。哪种细胞类型 释放导致关节炎症和软骨退化的外体还没有得到很好的研究。 与这一提议特别相关的是，我们已经证明了RASF外切体(RA-Exo)激活了肿瘤坏死因子- 受体相关因子2(TRAF2)介导的NF-B和JNK2途径的激活 TRAF2的稳定化。更重要的是，我们的初步数据清楚地表明，芳烃受体 类风湿关节炎(RA)患者滑膜中AHR的表达显著升高。表达与以下因素正相关 骨侵蚀和TRAF2的定位，有力地支持了该途径在发病机制中的相关性 类风湿性关节炎在人类中的作用。在机械上，AhR在RA-Exo中富含，而RA-Exo AhR是稳定所需的 TRAF2.我们的总体假设是，在RA-Exo中靶向AhR中心的网络会导致TRAF2 抑制TRAF2介导的RASF中NF-B和JNK2通路的激活。 因此，破坏RA外体中的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滑膜骨质侵蚀的发生 病人。 我们实现这一目标的计划在以下三个具体目标中概述： 1.确定导致小鼠关节炎发生的RA-Exo AhR网络。 2.确定RA-Exo AhR相关激酶活性是否介导TRAF2AF的解离 来自TRAF2复合体。 3.确定阻止VCIP135招募到RA-Exo AhR是否会导致防止 HuRASF/SCID小鼠模型中侵蚀性关节炎的发展。 这项研究的积极成果将为未来的产品开发提供机构驱动小说的基础 治疗类风湿关节炎的药物。此外，它对预测无反应性RA-Exo的生物标志物具有较高的价值。 在开始抗肿瘤坏死因子或个体化药物治疗之前的个人。

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.