ZBP1 activation

项目总结/摘要 假定的核苷酸传感器ZBP 1可以触发坏死性细胞死亡或转录反应， 遗传学研究表明，这种途径是宿主防御一系列病毒病原体所必需的。 此外，最近的研究表明，在某些情况下，ZBP 1可以在无菌条件下被激活。 条件下，暗示内源性细胞产物作为潜在的ZBP 1配体。然而，尽管长期研究， 负责激活ZBP 1的配体及其与核苷酸传感的其他组分的相互作用 双链RNA、核糖核蛋白和病毒的Z型核酸等， 所有物种都被认为是配体。ZBP 1仅与另一个基因共享其关键核苷酸传感结构域， 哺乳动物蛋白ADAR 1。ADAR 1灭活内源性dsRNA物质以限制自身炎症 病理学和人类患者中ADAR 1的突变导致严重的自身免疫性疾病Acardi， Goutieres综合征（AGS）。我们假设ADAR 1和ZBP 1竞争一个共同的内源性 配体，其被ADAR 1灭活是限制ZBP 1激活所必需的。为了支持这一观点， 在新开发的人类ADAR 1突变小鼠模型中观察到的ADAR 1突变通过消融 ZBP 1.这一发现支持了我们的假设，也意味着与丧失相关的自身免疫病理学 ADAR 1功能的降低是由ZBP 1依赖性炎症和细胞死亡的激活引起的。使用这些 作为一个起点，这里提出的工作将调查ZBP 1激活和功能， 追求三个目标：首先，我们将使用ADAR 1突变和其他新的小鼠模型，以促进 内源性ZBP 1配体分离和鉴定。第二，我们将评估 坏死性凋亡以及ZBP 1介导的炎症信号传导对人类肿瘤动物模型的病理学的影响 AGS由ADAR 1突变触发，并测试坏死性凋亡抑制剂改善这种病理的能力。 第三，我们将研究其他dsRNA传感器，包括MDA 5和PKR，对ZBP 1配体形成的作用 和坏死性凋亡途径激活。这项工作将揭示ZBP 1功能的关键方面， 鉴定ZBP 1依赖性坏死性凋亡作为改善AGS潜在可治疗靶点。

Project Summary/Abstract The putative nucleotide sensor ZBP1 can trigger necroptotic cell death or transcriptional responses, and genetic studies indicate that this pathway is required for host defense against an array of viral pathogens. Furthermore, recent studies show that in some circumstances ZBP1 can become activated under sterile conditions, implicating endogenous cellular products as potential ZBP1 ligands. However, despite long study, the ligand responsible for activating ZBP1 and its interplay with other components of the nucleotide sensing machinery remain controversial, with double-stranded RNA, ribonucleoprotein, and viral Z-form nucleic acid species all suggested as ligand. ZBP1 shares its key nucleotide sensing domain with only one other mammalian protein, ADAR1. ADAR1 inactivates endogenous dsRNA species to limit autoinflammatory pathology, and mutations in ADAR1 in human patients lead to the severe autoimmune disease Acardi- Goutieres syndrome (AGS). We hypothesize that ADAR1 and ZBP1 compete for a common endogenous ligand, whose inactivation by ADAR1 is required to limit ZBP1 activation. In support of this idea, the pathology observed in a newly-developed mouse model of human ADAR1 mutation was fully rescued by ablation of ZBP1. This finding supports our hypothesis, and also implies that autoimmune pathology associated with loss of ADAR1 function is caused by activation of ZBP1-dependent inflammation and cell death. Using these observations as a starting point, the work proposed here will investigate ZBP1 activation and function by pursuing three Aims: First, we will use ADAR1 mutation and additional new mouse models to facilitate isolation and identification of an endogenous ZBP1 ligand. Second, we will assess the contribution of necroptosis as well as ZBP1-mediated inflammatory signaling to the pathology of an animal model of human AGS triggered by ADAR1 mutation, and test the ability of necroptosis inhibitors to ameliorate this pathology. Third, we will investigate the role of other dsRNA sensors, including MDA5 and PKR, to ZBP1 ligand formation and necroptotic pathway activation. Together this work will both reveal key aspects of ZBP1 function, and identify ZBP1-dependent necroptosis as a potentially treatable target to ameliorate AGS.