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 表现出人类白细胞抗原供者特异性抗体(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)和一种称为移植的进行性血管疾病 血管病变(TV)。虽然CAMR和TV是跨越不同固体器官的非常重要的临床问题 移植针对HLAI和HLAII的DSA促进CAMR和TV的机制 还不能理解。防治CAMR和TV的新机制靶点和治疗方法 都是迫切需要的。以前，我们证明了DSA诱导的人类白细胞抗原分子的连接表达在 内皮细胞表面(ECs)诱导调节生存、增殖和迁移的信号通路， 所有这些都与电视高度相关。然而，人类白细胞抗原的连接所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的有效靶向治疗 效应器的功能是防止CAMR和TV。根据我们的新结果，我们假设转录共- 激活子是相关蛋白(YAP)及其与WW结构域平行的转录共激活子 PDZ结合基序(TAZ)是河马途径的两个中心效应器，是下游的汇聚点 内皮细胞中DSA启动的有丝分裂和迁移信号的整合。虽然抑制了 转录因子或其共激活子的活性是一种具有挑战性的策略，最近的证据表明，一种新的 通过他汀类药物瞄准YAP/TAZ活动的途径。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了有益的作用。基于大量的初步研究， 这一提议的中心假设是，YAP及其伴生的TAZ在促进 内皮细胞对DSA的反应以及FDA批准的他汀类药物的增殖和迁移 抑制这些细胞的YAP/TAZ功能。我们假设的一个基本翻译含义是药物 可能是通过阻断促生长因子YAP/TAZ来预防CAMR的一个重要因素 ECS中的信令。我们建议通过追求三个具体目标来探索这一中心假设：1)确定 YAP在抗HLAI或HLAII抗体刺激的人内皮细胞中的调节和作用： Src激酶的作用。2)确定他汀类药物抑制YAP功能、增殖和迁移的机制(S) 抗HLAI或HLAII型抗体刺激的内皮细胞。3)他汀类药物对YAP的影响 和体内CAMR使用一种开发TV的同种异体心脏移植的新模型。我们建议SRC/YAP/TAZ AXIS在抗体介导的EC增殖中起关键作用，他汀类药物通过 YAP/TAZ抑制。我们预计，Src/YAP/TAZ轴将成为CAMR中的一个新靶点 推动进一步研究以重新定位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所致的同种异体移植物慢性损伤。

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.