Genetic regulation of ductular reaction in liver injury and regeneration

肝损伤和再生中导管反应的基因调控

• 批准号: 10595652
• 负责人: Adam David Gracz
• 金额: $ 39.97万
• 依托单位: EMORY UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-04-01 至 2026-01-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10595652
• 关键词: Acute; Adult; Alleles; Biliary; Binding; Biological Assay; Cartilage; Cell Differentiation process; Cell Proliferation; Cells; Cholestasis; Chromatin; Chronic; Data; Development; Duct (organ) structure; Enhancers; Epigenetic Process; Epithelial Cell Proliferation; Epithelial Cells; Epithelium; Equilibrium; Esophagus; Exhibits; Functional disorder; Gene Expression; Genes; Genetic; Genetic Transcription; Genome; Genomic approach; Genomics; Goals; Hair follicle structure; Hepatocyte; Heterogeneity; Homeostasis; Human; Hybrids; Impairment; In Vitro; Injury; Intrahepatic bile duct; Knockout Mice; Knowledge; Liver; Liver Failure; Liver Regeneration; Liver diseases; Maps; Mediating; Modeling; Mus; Natural regeneration; Organoids; Phenotype; Play; Population; Process; Proliferating; Reaction; Regenerative Medicine; Regenerative capacity; Regulation; Reporting; Role; Specific qualifier value; Testing; Tissues; Transgenes; end stage liver disease; functional genomics; gene regulatory network; genome-wide; in vivo; in vivo Model; injury and repair; insight; intrahepatic; liver function; liver injury; liver transplantation; mouse model; multiple omics; novel therapeutics; regenerative; repaired; response; severe injury; stem cell function; stem cells; targeted treatment; therapeutic target; tissue regeneration; transcription factor; transcriptome sequencing; transcriptomics; transdifferentiation

PROJECT SUMMARY The liver exhibits remarkable capacity for regeneration, but chronic injury or severe acute damage can overwhelm compensatory responses and result in liver failure. The need for transplantable livers regularly exceeds the donor pool, necessitating the development of new regenerative medicine-based therapies and a deeper understanding of the liver’s endogenous repair mechanisms. This proposal seeks a mechanistic understanding of gene regulatory networks underlying ductular reaction (DR), a damage response associated with a broad range of liver injury and disease. DR is defined by the proliferative expansion of biliary epithelial cells (BECs) and can involve context-dependent lineage conversion between mature hepatocytes and BECs that contributes to tissue regeneration. The genetic regulation of DR remains poorly understood, including how BECs balance proliferation and phenotypic plasticity. Sox9 is a transcription factor required for stem/progenitor cell function in a number of epithelial tissues and has been shown to establish cellular identity through genome-wide effects on the chromatin landscape. In the liver, Sox9 is required for timing of BEC specification in development and is broadly expressed in adult BECs. Our lab recently used a Sox9EGFP transgene to study BEC heterogeneity and showed that Sox9 is expressed at distinct levels in subpopulations of BECs and peribiliary hybrid hepatocytes (HybHeps) during homeostasis and cholestasis. New findings from our lab also demonstrate abnormalities in BECs of adult Sox9 knockout mice. The central hypothesis of this proposal is that Sox9 functions as a master regulator of DR, by inhibiting proliferation and promoting BEC identity. The following specific aims will test this hypothesis: Aim 1A will determine the role of Sox9 in damage induced BEC proliferation, through the use of the Sox9EGFP allele and (1) combined BEC/hepatocyte or (2) BEC-specific Sox9 knockout mouse models. Aim 1B will determine the role of Sox9 in bi-directional BEC-to-hepatocyte plasticity, through complementary in vivo lineage tracing and in vitro organoid assays. Aim 2A will map the chromatin regulatory landscape of DR, by integrating transcriptomics and chromatin assays in BEC subpopulations during liver injury. Aim 2B will determine the genomic regulatory impact of Sox9 in DR by applying single cell multi-omics to BEC- specific Sox9 knockout mouse models. The data generated in this project will provide fundamental mechanistic insight into genetic regulation of DR and identify regulatory nodes for therapeutic targeting to enhance regeneration in end stage liver disease.

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 超过代偿反应并导致肝功能衰竭。需要定期移植肝脏 超过了供体库，需要开发新的再生医学为基础的疗法， 深入了解肝脏的内源性修复机制。该提案寻求一种机械的 了解小管反应（DR）的基因调控网络，这是一种与损伤相关的反应， 各种肝脏损伤和疾病DR的定义是胆管上皮细胞的增殖性扩张， 细胞（BEC）之间的相互作用，并且可以涉及成熟肝细胞和BEC之间的背景依赖性谱系转换， 有助于组织再生DR的遗传调控仍然知之甚少，包括BEC如何 平衡增殖和表型可塑性。Sox 9是干细胞/祖细胞所需的转录因子 在许多上皮组织中起作用，并已显示通过全基因组的表达建立细胞特性。 对染色质景观的影响在肝脏中，Sox 9是BEC特化发育所需的时间 并且在成体BEC中广泛表达。我们实验室最近使用Sox 9 EGFP转基因研究BEC异质性 结果表明，Sox 9在BEC亚群和胆管周围杂种中表达水平不同， 肝细胞（HybHeps）在体内平衡和胆汁淤积。我们实验室的新发现也证明了 成年Sox 9敲除小鼠BEC的异常。这个提议的核心假设是Sox 9的功能是 作为DR的主要调节剂，通过抑制增殖和促进BEC身份。以下具体目标 目的1A将通过以下方式确定Sox 9在损伤诱导的BEC增殖中的作用： 使用Sox 9 EGFP等位基因和（1）组合的BEC/肝细胞或（2）BEC特异性Sox 9敲除小鼠 模型目的1B将确定Sox 9在双向BEC-肝细胞可塑性中的作用，通过 互补的体内谱系追踪和体外类器官测定。Aim 2A将绘制染色质调节蛋白 DR的景观，通过整合转录组学和染色质测定在BEC亚群在肝损伤。 目的2B将通过将单细胞多组学应用于BEC来确定Sox 9在DR中的基因组调控影响。 特异性Sox 9敲除小鼠模型。在这个项目中产生的数据将提供基本的机械 深入了解DR的遗传调控，并确定治疗靶向的调控节点，以增强 终末期肝病的再生。