Establishing Sox9 as a regulator of intrahepatic bile duct development and regeneration

项目摘要 肝脏表现出显著的再生能力，但慢性损伤或严重的急性损伤可以 压倒再生机制并导致终末期肝病。缺乏有效的治疗方法 再加上供体器官可用性不足，需要开发新的再生医学- 基础疗法和更深入地了解肝脏修复的基本机制。转录因子 Sox 9是许多上皮组织中干/祖细胞功能所必需的，并且已被证明 建立蜂窝身份。在肝脏中，Sox 9是胆管上皮细胞（BEC）特化的时间所必需的。 它广泛表达于成体BEC中。Sox 9缺陷性胆管炎小鼠模型的建立 Alagille综合征我的初步数据表明Sox 9基因敲除小鼠的导管缺乏，这表明 Sox 9在BEC规范中的核心作用。该建议旨在定义肝内BEC的功能调节 Sox 9在发育和损伤相关的导管反应（DR）过程中的网络。DR是一种常见的 BEC是肝脏疾病的特征，并由BEC的增殖性扩张定义。此外，根据 损伤类型、时间和/或损伤程度，DR可涉及成熟肝细胞之间的谱系转换 和促进组织再生的BEC。DR的遗传调控仍然知之甚少。的 该建议的中心假设是，Sox 9是建立适当的肝内BEC所必需的 发育中的网络和小管反应。我将通过以下具体目标来检验这一假设： 目的1A建立Sox 9在小鼠肝内胆管形成的发育要求 通过使用组织学、胆汁酸测定、类器官测定和3D组织成像。目标1B将进行调查 Sox 9在通过scRNA-seq指定BEC亚群中的作用。目标2将决定Sox 9如何维持 使用诱导型Sox 9敲除小鼠在DR期间的成年BEC群体。将通过肝脏测定BEC功能 血清生化、组织学和谱系追踪。该项目将确定Sox 9如何建立和 保持BEC的人口，并为我提供培训，以实现我获得以研究为中心的教师的目标 研究胃肠道组织的稳态和再生。这项工作意义重大，因为研究结果将有助于 了解肝脏修复的基本机制，可用于确定新的靶点， 在终末期肝病中恢复肝功能的治疗方法。

PROJECT SUMMARY The liver exhibits remarkable capacity for regeneration, but chronic injury or severe acute damage can overwhelm regenerative mechanisms and lead to end-stage liver disease. The lack of effective medical therapies combined with insufficient donor organ availability necessitates the development of new regenerative medicine- based therapies and a deeper understanding of the basic mechanisms of liver repair. The transcription factor Sox9 is required for stem/progenitor cell function in a number of epithelial tissues and has been shown to establish cellular identity. In the liver, Sox9 is required for timing of biliary epithelial cell (BEC) specification in development and is broadly expressed in adult BECs. Sox9 deficiency worsens cholangiopathy in mouse models of Alagille Syndrome. My preliminary data demonstrate ductal paucity in Sox9 knockout mice, suggesting a central role for Sox9 in BEC specification. This proposal seeks to define functional regulation of intrahepatic BEC networks by Sox9, during development and injury-associated ductular reaction (DR). DR is a common characteristic of liver disease and is defined by the proliferative expansion of BECs. Furthermore, based on damage type, timing, and/or extent of damage, DR can involve lineage conversion between mature hepatocytes and BECs that contributes to tissue regeneration. The genetic regulation of DR remains poorly understood. The central hypothesis of this proposal is that Sox9 is required to establish proper intrahepatic BEC networks in development and ductular reaction. I will test this hypothesis with the following specific aims: Aim 1A will establish the developmental requirement of Sox9 to form functional intrahepatic bile ducts in mice through the use of histology, bile acid assays, organoid assays, and 3D tissue imaging. Aim 1B will investigate the role of Sox9 in specifying BEC subpopulations through scRNA-seq. Aim 2 will determine how Sox9 maintains adult BEC populations during DR using inducible Sox9 knockout mice. BEC function will be assayed by liver serum biochemistry, histology, and lineage tracing. This project will determine how Sox9 establishes and maintains BEC populations and provide me with training towards my goal of obtaining a research-focused faculty position studying GI tissue homeostasis and regeneration. This work is significant because the findings will help develop an understanding of basic mechanisms of liver repair that can be used to identify novel targets for therapeutics to restore liver function in end stage liver disease.