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

项目总结 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能 压倒再生机制，导致终末期肝病。缺乏有效的药物治疗 再加上供体器官供应不足，有必要开发新的再生医学-- 以治疗为基础，对肝脏修复的基本机制有更深入的了解。转录因子 SOX9在许多上皮组织中是干细胞/祖细胞功能所必需的，并已被证明 建立手机身份。在肝脏中，Sox9是胆管上皮细胞(BEC)规范的计时所必需的 在成体BEC中广泛表达。SOX9缺乏加重小鼠胆管病变 阿拉格尔综合症。我的初步数据显示Sox9基因敲除小鼠的导管缺乏，这表明 Sox9在BEC规范中的核心角色。本提案旨在定义肝内BEC的功能调节。 SOX9的网络，在发育和损伤相关的导管反应(DR)中。DR是一种常见的 以肝脏疾病为特征，以BECs的增殖性扩张为特征。此外，基于 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BECs。DR的基因调控仍然知之甚少。这个 这一提议的中心假设是，Sox9是建立适当的肝内BEC所必需的 发育中的网络和导管反应。我将通过以下具体目标来检验这一假设： 目的1建立SOX9在小鼠肝内形成功能性胆管的发育条件 通过使用组织学、胆汁酸分析、有机物分析和3D组织成像。AIM 1B将进行调查 Sox9在通过scRNA-seq指定BEC亚群中的作用。目标2将决定Sox9如何维持 使用可诱导的sox9基因敲除小鼠的DR期间的成年BEC群体。BEC功能将通过肝脏进行检测 血清生化、组织学和血统追踪。该项目将决定Sox9如何建立和 保持BEC人口，并为我提供培训，以实现我获得以研究为重点的教员的目标 研究胃肠道组织的动态平衡和再生。这项工作意义重大，因为这些发现将有助于 了解肝脏修复的基本机制，可用于确定新的靶点 终末期肝病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.