Molecular Mechanisms of Toxin-InducedBiliary Atresia

项目概要（与原始提交资料相比无变更） 胆道闭锁（BA）是一种新生儿胆管病，是肝移植的主要适应症， 儿科人群。人类BA的病因仍然不清楚，然而，BA在澳大利亚新生儿中流行， 与母体摄入Dysphania种植物相关的家畜支持毒性病因学。使用一项 体内斑马鱼胆汁分泌试验，我们已经分离出biliatresone，一种新的植物生物碱，具有选择性 肝外胆汁毒性可能导致BA综合征（1）。这种毒素介导的 BA模型概括了人类BA的主要特征，因此可用于模拟这种罕见但 重要的儿科肝病。 胆汁酸是一种强亲电试剂，我们已经证明氧化还原应激和蛋白质组应激起着关键作用 胆汁酸中毒。具体而言，我们发现：1）肝外胆管细胞表现出显著的 在基线时和用胆固醇酯治疗后，与对照组相比， 肝内胆管细胞和肝细胞;和2）胆脂松毒性可以通过药理学改变 和GSH氧化还原稳态的遗传操纵（2）。本提案的总体目标是继续 使用胆固醇作为损伤模型，用于定义胆管细胞对毒性损伤的应激反应，并探索 应激反应与胆道损伤遗传易感性之间的联系。该提案包括两个 具体目标。在目标1中，我们将定义肝脏氧化还原异质性的机制， 在斑马鱼模型中对毒性损伤的易感性。在目标2中，我们将定义胆管细胞蛋白质组之间的联系， 和氧化还原应激反应和遗传易感性氧化还原诱导的胆管细胞损伤使用斑马鱼和 来源于诱导多能干细胞的人胆管细胞。 拟议的实验将揭示新的信息的分子机制的基础 我们希望这将刺激BA和其他疾病的新治疗策略的发展。 胆管疾病

PROJECT SUMMARY (NO CHANGES FROM ORIGINAL SUBMISSION) Biliary atresia (BA) is a neonatal cholangiopathy that is the leading indication for liver transplantation in the pediatric population. The etiology of human BA remains obscure, however, BA epidemics in newborn Australian livestock associated with maternal ingestion of the Dysphania species plant support a toxic etiology. Using an in vivo zebrafish biliary secretion assay, we have isolated biliatresone, a novel plant isoflavonoid with selective extrahepatic biliary toxicity that is likely responsible for the Dysphania BA syndrome (1). This toxin-mediated BA model recapitulates the cardinal features of human BA and thus can be used to model this rare but important pediatric liver disease. Biliatresone is a strong electrophile and we have shown that redox stress and proteomic stress play critical roles in biliatresone toxicity. Specifically, we have found that: 1) extrahepatic cholangiocytes exhibit a significantly more oxidized glutathione (GSH) redox potential both at baseline and after treatment with biliatresone compared to intrahepatic cholangiocytes and hepatocytes; and 2) biliatresone toxicity can be altered through pharmacologic and genetic manipulation of GSH redox homeostasis (2). The overarching goals of this proposal are to continue use biliatresone as an injury model for defining cholangiocyte stress responses to toxic insults and to explore the links between stress responses and genetic susceptibility to biliary injury. The proposal consists of two specific aims. In Aim 1, we will define mechanisms of liver redox heterogeneity that confer differential susceptibility to toxic injury in the zebrafish model. In Aim 2, we will define links between cholangiocyte proteomic and redox stress responses and genetic susceptibility to redox-induced cholangiocyte injury using zebrafish and human cholangiocytes derived from induced pluripotent stem cells. The proposed experiments will reveal novel information about the molecular mechanisms underlying the pathogenesis of BA that we hope will spur the development of new therapeutic strategies for BA and other cholangiopathies.