In vitro modelling of biliary development and diseases

胆汁是一种在肝脏中产生的有毒液体，通过被称为胆管的管状结构转移到肠道，在那里它有助于脂肪的吸收。在胆管疾病(胆管病)中，胆管不能有效地容纳和转移胆汁。结果，有毒的胆汁从胆管中泄漏出来，并在肝脏中积聚，造成严重损害。不幸的是，我们对导致胆道疾病的确切机制的了解非常有限。由于在实验室获取和维护活体胆管样本的技术困难，以及缺乏忠实复制这种疾病的动物模型，该领域的研究受到阻碍。然而，迫切需要破译疾病机制，以开发新的诊断测试和治疗方案。胆道疾病在所有肝脏疾病中占很大比例，具有很高的死亡率。唯一可用的治疗方法是肝移植，这是一种挽救生命但昂贵且具有挑战性的手术，需要终身药物治疗和随访，并因全国肝脏捐赠者短缺而复杂化。Alagille综合征(AGS)是一种遗传性疾病。虽然它累及多个器官，但由妊娠和生命早期胆管发育不良引起的胆道疾病是最常见的临床表现。肝移植仍然是唯一的治疗选择。与其他胆道疾病相比，AGS的研究有两个重要的优点：首先，其发病机制并不完全未知，因为导致它的遗传突变已经被描述过。其次，鉴于AGS与胆管发育密切相关，阐明其发病机制将为胆管的正常发育提供重要信息。胆管发育在一定程度上与所有导致儿科肝移植的儿童胆道疾病有关。因此，研究AGS可能会增进我们对整个胆道疾病的认识。本项目的目的是开发一种新的方法，在实验室中产生大量功能完整的胆管复制品。由此产生的导管将为研究任何胆道疾病、测试和开发新的治疗方法提供一个极好的模型。我建议应用这种方法来建立首个AGS的原则性疾病模型，并阐明其发病机制。我已经在实现这一目标方面取得了重大进展。利用干细胞技术，我从健康人的皮肤样本开始，成功地创造了具有功能的胆管复制品。我打算用同样的方法来产生和研究AGS患者的胆管。一旦导管被创建，我将使用尖端技术来破译导致AGS的一系列事件，并试图通过干预和改变这些事件来‘拯救’患病的导管。这个项目将阐明AGS的驱动机制，促进开发新的测试来早期识别疾病，开发新的标记物来预测其进程，以及替代肝移植的新的治疗方案。最终，它将有助于提高患者的生活质量，减轻移植等待名单上的压力，并将AGS从一种无法治疗的疾病转变为一种可管理的情况。此外，所描述的平台有可能从任何胆道疾病患者那里产生大量的胆管复制品。因此，它将为任何致力于胆管研究的研究小组提供一种强大的新型疾病建模工具，克服与缺乏胆管组织相关的困难，为未来认识和治疗胆道疾病铺平道路。

Bile is a toxic fluid produced in the liver and transferred through tubular structures known as bile ducts to the gut, where it helps with fat absorption. In bile duct disorders (cholangiopathies), the bile ducts fail to contain and transfer bile effectively. As a result, toxic bile leaks out of the ducts and accumulates in the liver causing significant damage. Unfortunately, our understanding of the exact mechanisms leading to biliary disease is very limited. Research in the field is hindered by technical difficulties in obtaining and maintaining live bile duct samples in the laboratory and the lack of animal models faithfully reproducing the disease. Nevertheless, the need to decipher the disease mechanisms, towards developing new diagnostic tests and treatment options is very pressing. Bile duct disorders account for a major proportion of all liver disease, carrying significant mortality. The only available treatment is liver transplantation, a lifesaving but expensive and challenging operation, requiring lifelong medication and follow-up and complicated by the national shortage of liver donors.Alagille syndrome (AGS) is an inherited disorder. Although it involves multiple organs, biliary disease caused by poor bile duct development in pregnancy and early life constitutes the most common clinical manifestation. Liver transplantation remains the only treatment option. Compared to other bile duct disorders the study of AGS has two important advantages: Primarily, the disease mechanism is not completely unknown, as the hereditary mutation causing it has already been described. Secondarily, in view of the close association between AGS and bile duct development, elucidating the disease mechanism will provide significant information on how bile ducts normally develop. Duct development is implicated to some extent in all childhood biliary disorders leading to paediatric liver transplantation. Therefore, studying AGS may advance our knowledge on a whole group of biliary diseases.The aim of this project is to develop a novel method for generating large amounts of fully functional bile duct replicas in the laboratory. The resulting ducts will provide an excellent model to study any biliary disease, test and develop new therapies. I propose applying this method for generating the first proof-of-principle disease model for AGS and elucidating the disease mechanism. I have already made significant progress towards achieving this goal. Using the technology of stem cells, I have successfully created functional bile duct replicas, starting from healthy individuals' skin samples. I intend to use the same approach to generate and study bile ducts from AGS patients. Once the ducts have been created, I will use cutting edge technology to decipher the series of events leading to AGS and attempt to 'rescue' the diseased ducts by intervening and altering these events.This project will shed light on the mechanisms driving AGS, facilitating the development of new tests for identifying the disease in early stages, new markers for predicting its course and new treatment options alternative to liver transplantation. Ultimately, it will contribute to improving the patients' quality of life, reducing pressure on the transplant waiting list and changing AGS from an untreatable disease to a manageable condition. Furthermore, the platform described has the potential to generate large amounts of bile duct replicas from patients with any biliary disorder. Therefore, it will provide a powerful novel disease modelling tool for the benefit of any research group working on bile ducts, overcoming the difficulties related to lack of biliary tissue and paving the road towards understanding and treating biliary disease in the future.