Targeting the transcriptional co-activators YAP and TAZ with statins to prevent solid organ transplant rejection by HLA donor specific antibodies

项目摘要 表现出HLA供体特异性抗体（DSA）的实体器官移植受者由于以下原因而面临移植物丢失的风险 慢性抗体介导的排斥反应（cAMR），并发展为一种称为移植的进行性血管疾病 血管病变（TV）。尽管cAMR和TV是跨不同实体器官的高度显著的临床问题， 针对HLA I和HLA II的DSA导致cAMR和TV的机制是 还不明白。预防和治疗cAMR和TV的新机制靶点和治疗方法 是迫切需要的。以前，我们证明了DSA诱导的HLA分子连接表达在 内皮细胞（ECs）表面诱导的信号通路调节存活、增殖和迁移， 所有这些都与电视高度相关。然而，HLA连接刺激的关键转录程序， 分子仍有待鉴定。这种认识上的差距阻碍了DSA的有效治疗靶向 效应器功能，以防止cAMR和TV。根据我们的新结果，我们认为转录协同作用， 激活因子是相关蛋白（雅普）及其含有其旁腺WW-domain的转录共激活因子， PDZ结合基序（TAZ）是Hippo信号通路的两个中枢效应子，是下游的会聚点 以及在由DSA启动的有丝分裂和迁移信号传导中的整合。虽然抑制了 转录因子或其共激活因子的活性是一个具有挑战性的策略，最近的证据表明，一个新的 通过他汀类药物靶向雅普/TAZ活性的途径。重要的是，流行病学研究表明， 他汀类药物在临床移植人群中发挥有益作用。根据大量的初步研究， 这一建议的中心假设是，雅普及其附属的TAZ在促进 内皮细胞对DSA的反应性增殖和迁移，以及FDA批准的他汀类药物 抑制这些细胞中雅普/TAZ功能。我们的假设的一个基本的翻译含义是， 他汀类药物家族的一个重要因素是通过阻断促生长雅普/TAZ来预防cAMR EC中的信号。我们建议通过追求三个具体目标来探索这个中心假设：1）确定 雅普在用针对HLA I或HLA II的抗体刺激的人EC中的调节和功能： Src激酶的作用。2)定义他汀类药物抑制雅普功能、增殖和迁移的机制 用针对HLA I或HLA II的抗体刺激的EC。3)描述他汀类药物对雅普的影响 和cAMR在体内使用一种新的心脏移植同种异体移植物模型，发展电视。我们建议Src/雅普/TAZ 轴在抗体介导的EC增殖中起着关键作用，他汀类药物通过 雅普/TAZ抑制。我们预计Src/雅普/TAZ轴将成为cAMR的新靶点， 推动进一步研究重新定位FDA批准的他汀类药物，无论是单独使用还是与Src抑制剂联合使用 用于预防DSA引起的慢性同种异体移植物损伤。

PROJECT ABSTRACT Solid organ transplant recipients exhibiting HLA donor specific antibodies (DSA) are at risk for graft loss due to chronic antibody-mediated rejection (cAMR) and develop a progressive vascular disease known as transplant vasculopathy (TV). Although cAMR and TV are highly significant clinical problems across different solid organ transplants the mechanisms by which DSAs directed against HLA I and HLA II contribute to cAMR and TV are not yet understood. Novel mechanistic targets and therapeutic approaches to prevent and treat cAMR and TV are urgently needed. Previously, we demonstrated that DSA-induced ligation of HLA molecules expressed in the surface of endothelial cells (ECs) induces signaling pathways that regulate survival, proliferation and migration, all of which are highly relevant to TV. However, the key transcriptional programs stimulated by ligation of HLA molecules remain to be identified. This gap in understanding hinders effective therapeutic targeting of DSA effector functions to prevent cAMR and TV. Based on our new results, we posit that the transcriptional co- activator Yes-Associated Protein (YAP) and its paralog WW-domain-containing Transcriptional co-Activator with PDZ-binding motif (TAZ), two central effectors of the Hippo pathway, are downstream points of convergence and integration in the mitogenic and migratory signaling initiated by DSAs in ECs. Although inhibition of the activity of transcription factors or their co-activators is a challenging strategy, recent evidence suggests a new avenue to target YAP/TAZ activity via drugs of the statin family. Importantly, epidemiological studies indicate that statins exert a beneficial effect in clinical transplant populations. Based on substantial preliminary studies, the central hypothesis of this proposal is that YAP and its paralog TAZ play a crucial role in promoting the proliferation and migration of ECs in response to DSAs and that the FDA-approved drugs of the statin family inhibit YAP/TAZ function in these cells. A fundamental translational implication of our hypothesis is that the drugs of the statin family can be an important element in preventing cAMR by blocking growth-promoting YAP/TAZ signaling in ECs. We propose to explore this central hypothesis by pursuing three Specific Aims: 1) Determine the regulation and function of YAP in human ECs stimulated with antibodies directed against HLA I or HLA II: role of Src kinases. 2) Define the mechanism(s) by which statins inhibit YAP function, proliferation and migration of ECs stimulated with antibodies directed against HLA I or HLA II. 3) Characterize the impact of statins on YAP and cAMR in vivo using a novel model of heart graft allograft that develop TV. We propose that the Src/YAP/TAZ axis plays a critical role in antibody-mediated EC proliferation and that statins inhibit EC proliferation and TV via YAP/TAZ inhibition. We anticipate that the Src/YAP/TAZ axis will emerge as a novel target in cAMR thus propelling further studies to reposition FDA-approved statins either singly or in combination with Src inhibitors for preventing chronic allograft injury induced by DSAs.