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.

项目概要 肝脏表现出卓越的再生能力，但慢性损伤或严重急性损伤可能会导致肝脏损伤。 压倒代偿反应并导致肝衰竭 需要定期移植肝脏。 超出了捐赠者库，需要开发新的基于再生医学的疗法和 该提案寻求更深入地了解肝脏的内源性修复机制。 了解导管反应 (DR) 背后的基因调控网络，这是一种相关的损伤反应 DR 的定义是胆管上皮的增殖性扩张。 细胞（BEC），并且可能涉及成熟肝细胞和 BEC 之间的背景依赖性谱系转换， DR 的基因调控，包括 BEC 如何促进组织再生，目前仍知之甚少。 Sox9 是干细胞/祖细胞所需的转录因子。 在许多上皮组织中发挥功能，并已被证明可以通过全基因组建立细胞身份 对肝脏中染色质景观的影响，BEC 规范的开发时机需要 Sox9。 我们的实验室最近使用 Sox9EGFP 转基因来研究 BEC 异质性。 并表明 Sox9 在 BEC 和胆周杂种亚群中以不同水平表达 我们实验室的新发现也证明了稳态和胆汁淤积期间的肝细胞（HybHeps）。 成年 Sox9 敲除小鼠的 BEC 异常 该提议的中心假设是 Sox9 发挥作用。 作为 DR 的主要调节者，通过抑制增殖和促进 BEC 特性实现以下具体目标。 将检验这一假设：目标 1A 将确定 Sox9 在损伤诱导的 BEC 增殖中的作用，通过 使用 Sox9EGFP 等位基因和 (1) 组合 BEC/肝细胞或 (2) BEC 特异性 Sox9 敲除小鼠 目标 1B 将通过以下方式确定 Sox9 在双向 BEC 至肝细胞可塑性中的作用。 互补的体内谱系追踪和体外类器官检测将绘制染色质调控图谱。 通过整合肝损伤期间 BEC 亚群的转录组学和染色质测定，了解 DR 的情况。 目标 2B 将通过将单细胞多组学应用于 BEC 来确定 Sox9 在 DR 中的基因组调控影响 该项目中生成的特定 Sox9 敲除小鼠模型将提供基本机制。 深入了解 DR 的基因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。