Isolation, Identification and Characterization of a Toxin Causing Biliary Atresia

引起胆道闭锁的毒素的分离、鉴定和表征

基本信息

批准号：
9131852
负责人：
MICHAEL A PACK
金额：
$ 44.8万
依托单位：
UNIVERSITY OF PENNSYLVANIA
依托单位国家：
美国
项目类别：
财政年份：
2011
资助国家：
美国
起止时间：
2011-04-01 至 2016-08-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/9131852
关键词：
3-Dimensional Adult Affect Age Animal Disease Models Antioxidants Apical Australia Bile fluid Biliary Biliary Atresia Binding Biological Biological Assay Candidate Disease Gene Cattle Cell Polarity Cells Child Childhood Cholestasis Chromosomes, Human, Pair 10 Clinical Complex Congenital atresia of extrahepatic bile duct Coupled Cysteine Data Diagnosis Disease Disease Outbreaks Duct (organ) structure Ductal Employee Strikes Environmental Exposure Epidemiology Etiology Extrahepatic Extrahepatic Cholestasis Fibrosis Fishes Funding Genetic Goals Health Histidine Human Human Chromosomes Immune system In Vitro Ingestion Libraries Link Liver Livestock Maps Mediating Messenger RNA Microtubules Modeling Molecular Mothers Mus Neonatal Newborn Infant Obstruction Oxidation-Reduction Oxidative Stress Pathogenesis Plants Poison Polyribosomes Population Predisposition Pregnancy Reduced Glutathione Reporting Research Personnel Resolution Role Sheep Signal Pathway Stress Structure Structure-Activity Relationship Testing Time Toxic effect Toxin Zebrafish base bile duct biological adaptation to stress chemical genetics cholangiocyte epidemiologic data genetic risk factor insight liver transplantation macrophage mutant neonate novel pregnant research study transcription factor

项目摘要

DESCRIPTION (provided by applicant): Biliary atresia (BA) is a fibrotic disorder that is the leading cause of neonatal cholestasis and the most common indication for liver transplant in the pediatric population. Although epidemiologic data suggest that BA arises from the interplay of genetic risk factors coupled with environmental exposures, the etiology is unknown. Insight into the pathogenesis of BA comes from the study of a naturally-occurring animal model of the disease. Over the last 40 years, there have been four outbreaks of BA in newborn livestock in Australia associated with ingestion of plants from the genus Dysphania by pregnant sheep and cows. Clinical and pathological findings from the affected lambs and calves show striking similarities with human BA, in particular marked fibrosis at the time of diagnosis. In our original proposal, we proposed to isolate the Dysphania biliary toxin. We now report that we have identified a selective extrahepatic biliary toxin, a previously undescribed isoflavonoid termed biliatresone, and have developed a new model of BA in larval zebrafish. Additionally, we have 1) identified structural features of biliatresone responsible for biliary toxicity, 2) demonstrated tht it binds reduced glutathione, cysteine and histidine in vitro and shown that the binding may be important for toxicity in zebrafish and mammalian cholangiocyte models, 3) identified a genetic link between toxin susceptibility in zebrafish and BA in humans, 4) demonstrated that biliatresone destabilizes mammalian cholangiocyte microtubules and alters cholangiocyte polarity, and 5) shown that biliatresone causes changes in Sox17 in mammalian cholangiocytes that are paralleled by changes observed in human BA livers. We hypothesize that biliatresone-induced toxicity is mechanistically relevant to human BA, and that signaling pathways related to susceptibility loci on human chromosome 10, oxidative stress, cell polarity, and Sox17 are critical to extrahepatic ductal atresia. Our overall goal is to employ a combined chemical, genetic, and cell biological approach to further understand the mechanism of extrahepatic duct obstruction and atresia. There are four specific aims: 1) to determine the effects of biliatresone on redox stress in the neonatal liver and bile ducts; 2) to determine the mechanism of biliatresone-mediated bile duct disruption at a cellular level, specifically to determine the relationship between oxidative stress, microtubules, and polarity in BA, and to identify signaling pathways downstream of Sox17 that could cause BA; 3) to identify genetic modifiers of biliatresone toxicity and determine their relevance to human BA; and 4) to synthesize and conduct structure-function studies of biliatresone and related compounds in order to identify critical structural features underlying toxicity. The proposed experiments will yield novel information about the mechanism of biliatresone-mediated BA; more importantly, they will provide insight into general mechanisms of extrahepatic ductal damage and potential therapies that are highly relevant to human BA.

描述（由应用提供）：胆道闭锁（BA）是一种纤维化疾病，是新生儿胆汁淤积的主要原因，也是小儿种群中肝移植的最常见指征。尽管流行病学数据表明BA是由遗传危险因素与环境暴露的相互作用引起的，但病因尚不清楚。对BA发病机理的洞察来自研究该疾病的天然动物模型。在过去的40年中，澳大利亚的新生儿牲畜爆发了四次BA爆发，与怀孕的绵羊和牛从吞咽困境中摄入植物有关。受影响的羔羊和犊牛的临床和病理发现表现出与人类BA的惊人相似性，特别是在诊断时明显的纤维化。在我们的原始提案，我们提议隔离烦躁的胆汁毒素。现在，我们报告说，我们已经确定了一种选择性的外雌性胆道毒素，这是一种先前未描述为胆汁毒素的异黄素，并在幼虫斑马鱼中开发了一种新的BA模型。 Additionally, we have 1) identified structural features of biliary resone responsible for biliary toxicity, 2) demonstrated tht it binds reduced glutathione, cysteine and histidine in vitro and shown that the binding may be important for toxicity in zebrafish and mammalian cholangiocyte models, 3) identified a genetic link between toxin susceptibility in zebrafish and BA in humans, 4)证明胆汁酮破坏了哺乳动物胆管细胞微管的稳定性，并改变了胆管细胞的极性，5）表明，胆汁酮会导致哺乳动物胆管细胞的Sox17的变化，这些变化与人类BA生活中观察到的变化相似。我们假设胆红素诱导的毒性在机械上与人类BA有关，并且与人类染色体上的易感性相关的信号通路，氧化应激，细胞极性和SOX17对膜外膜型型倾斜度至关重要。我们的总体目标是采用一种联合化学，遗传和细胞生物学方法来进一步了解肝外管阻塞和闭锁的机制。有四个特定的目的：1）确定胆汁肌对新生儿肝脏和胆管中氧化还原应激的影响； 2）确定在细胞水平上胆汁肌介导的胆管破坏的机理，特别是确定BA中氧化应激，微管和极性之间的关系，并鉴定Sox17下游的信号传导途径，可能导致BA； 3）鉴定胆汁毒性的遗传修饰剂并确定其与人类BA的相关性； 4）为了鉴定毒性基础的关键结构特征，合成和进行胆汁酮和相关化合物的结构功能研究。提出的实验将产生有关胆红素介导的BA机理的新信息；更重要的是，它们将洞悉与人类BA高度相关的脑外膜外损伤和潜在疗法的一般机制。