The role of Yes-associated protein kinase YAP1 in canonical and non-canonical Hippo pathway in the disintegrin metalloproteinase ADAM15-mediated anoikis resistance of synovial fibroblasts in rheumatoid arthritis

风湿性关节炎（RA）是最常见的炎症性风湿性关节病。基于遗传倾向，异常失调的免疫效应级联导致慢性炎症反应，导致软骨和骨的蛋白水解破坏，从而损害关节的完整性。对这些破坏性过程至关重要的主要细胞群是滑膜成纤维细胞，其在发炎的滑膜中被激活并分泌基质降解酶。类风湿性关节炎滑膜成纤维细胞（RASFs）的一个标志是其病理生理学增加的凋亡抗性。此外，RASF在发炎的滑液中自由游动，在失去基质接触后是至关重要的，这通常诱导细胞凋亡，从而使它们具有抗失巢凋亡性。它们获得性抗失巢凋亡的潜在机制知之甚少，尽管由于它们能够在一个受影响的关节内扩展和浸润到关节组织中的病理生理学相关，而且它们通过循环系统迁移到远处健康软骨中的潜力，如动物研究所证明的。在RA患者的滑膜中已经证实了去整合素金属蛋白酶ADAM 15的显著上调表达。此外，这种增加的ADAM 15表达在死亡受体Fas/CD 95连接后赋予抗凋亡作用。本研究的目的是分析转录辅激活因子YAP 1是否在依赖于ADAM 15的（非）经典Hippo通路中赋予RASF失巢凋亡诱导的细胞保护特性。因此，由失巢凋亡诱导引起的ADAM 15依赖性YAP 1介导的信号通路将在RASF中表征。基于该结果，将评估应用特异性信号转导抑制剂选择性抑制YAP 1信号传导，从而阻断RASFs抗失巢凋亡能力的增加。此外，YAP 1上游粘附分子和受体将被确定，以及YAP 1下游基因targets.The研究的目的是阐明在RASFs的抗失巢凋亡的YAP 1信号转导中的ADAM 15依赖的分子相互作用，并确定新的靶点，用于药理学抑制这些具有侵略性破坏性的滑膜细胞群在RA中。

Rheumatoid arthritis (RA) is the most frequent inflammatory rheumatic joint disease. Based on genetic predispositions aberrantly dysregulated immunological effector cascades lead to chronic inflammatory reactions, resulting in the proteolytic destruction of cartilage and bone, thus compromising the integrity of articular joints. A major cell population critical for these destructive processes are the synovial fibroblasts, which are activated in the inflamed synovial membrane and secrete matrix degrading enzymes. A hallmark of rheumatoid arthritis synovial fibroblasts (RASFs) is their pathophysiological increased apoptosis resistance. Also RASFs, freely swimming in inflamed synovial fluid, are vital after their loss of matrix contact, which usually induces apoptosis, thereby rendering them anoikis resistant. The underlying mechanism of their acquired anoikis resistance are poorly understood, albeit pathophysiological relevant due to their capability to expand and infiltrate into joint tissues within one affected joint, and moreover their potential to migrate into distant healthy cartilage via the circulatory system, as has been demonstrated by animal studies.In our previous studies, a marked upregulated expression of the disintegrin metalloproteinase ADAM15 has been demonstrated in synovial membranes of RA patients. Moreover, this increased ADAM15 expression confers anti-apoptotic effects upon ligation of the death receptor Fas/CD95. The aim of the present study is to analyze, whether the transcriptional coactivator YAP1 confers cytoprotective properties in (non)-canonical Hippo pathway dependent on ADAM15 upon anoikis induction in RASFs. Therefore, ADAM15-dependent YAP1-mediated signalling pathways elicited by anoikis induction will be characterized in RASFs. Based on the outcome, the application of specific signal transduction inhibitors to selectively inhibit YAP1 signalling, thereby blocking the increased anoikis resistance of RASFs, will be evaluated. Additionally, YAP1 upstream adhesion molecules and receptors will be identified as well as YAP1 downstream gene targets.The aim of the study is the elucidation of ADAM15-dependent molecular interactions in YAP1 signaling in the anoikis resistance of RASFs and the identification of new targets for a pharmacological inhibition of these aggressively destructive synovial cell population in RA.