The Role of the Notch Pathway in Bile Duct Development

切迹通路在胆管发育中的作用

• 批准号: 7681058
• 负责人: Kathleen Mary Loomes
• 金额: $ 33.94万
• 依托单位: CHILDREN'S HOSP OF PHILADELPHIA
• 依托单位国家: 美国
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-09-15 至 2011-02-28
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7681058
• 关键词: Ablation; Alagille Syndrome; Biliary; Biological Assay; Breeding; Cell Culture Techniques; Cell Line; Cells; Childhood; Classification; Complementary DNA; Cytokeratin; Development; Disease; Ductal; Embryo; Gene Targeting; Genes; Genetic; Genotype; Hepatocyte; Human; Inborn Genetic Diseases; Intrahepatic bile duct; Knock-out; Knockout Mice; Ligands; Liver; Microarray Analysis; Modeling; Molecular; Morbidity - disease rate; Mus; Mutant Strains Mice; Notch Signaling Pathway; Pathway interactions; Pattern; Phenotype; Population; Regulation; Research Personnel; Reverse Transcriptase Polymerase Chain Reaction; Role; Sampling; Signal Transduction; Specific qualifier value; Staging; Stimulus; System; Time; Tissue-Specific Gene Expression; Tissues; Transgenic Organisms; bile duct; body system; cDNA Arrays; jagged1 protein; mortality; mouse model; mutant; notch protein; novel; programs; recombinase; response; transcription factor

DESCRIPTION (provided by applicant): Inherited disorders of intrahepatic bile duct development are a major cause of morbidity and mortality in the pediatric population. In recent years, advances have been made toward understanding the genetic control of liver development, but relatively little is understood regarding the molecular regulation of bile duct development. Identification of Jag1 as the disease gene for Alagille syndrome (AGS), an autosomal dominant disorder characterized by bile duct paucity along with anomalies in other organ systems, has revealed a crucial role for Jag1 and the Notch pathway in bile duct development. Jag1 encodes a ligand in the Notch signaling pathway, which is involved in cell fate determination in many organ systems. Homozygous targeted disruption of Jag1 in a mouse model causes early embryonic lethality, and the heterozygous mutant mouse has no phenotype. We have generated a Jag1 conditional knockout mouse using the Cre/lox gene targeting system. This model will permit the systematic study of the role of Jag1 in the development of multiple organ systems at specified times during development. Preliminary studies have demonstrated expression of Jag1 in the primitive bile ducts, or ductal plate cells, which originate from hepatocyte precursors in developing mouse and human liver. We propose to selectively ablate Jag1 in the developing liver and bile ducts by breeding the Jag1-loxP mouse with a liver-specific Cre transgenic line. Using this mouse model, we will perform detailed studies of ductal plate remodeling and bile duct development in the absence of Jag 1. In addition, we will employ real time PCR and micro array analysis to identify unique downstream targets of the Notch pathway in bile duct development. As a complementary strategy, we propose to use a cell culture approach in which we will derive bipotential hepatoblast cell lines from embryonic wildtype and Jag1 null livers. We will assess their response to defined stimuli, and rescue the phenotype by transfecting with activated Notch

描述（由申请人提供）：肝内胆管发育的遗传疾病是小儿人群发病率和死亡率的主要原因。近年来，在理解肝脏发育的遗传控制方面取得了进步，但是关于胆管发育的分子调节，相对较少了解。将JAG1鉴定为Alagille综合征（AGS）的疾病基因，这是一种以胆管较差为特征的常染色体显性疾病，以及其他器官系统中的异常情况，揭示了JAG1和胆管导管发育中的Notch途径至关重要。 JAG1编码Notch信号通路中的配体，该配体参与了许多器官系统中的细胞命运测定。纯合靶向JAG1在小鼠模型中的破坏会引起早期胚胎致死性，而杂合突变小鼠没有表型。我们使用CRE/LOX基因靶向系统生成了JAG1条件基因敲除小鼠。该模型将允许系统地研究JAG1在开发过程中指定时间的多器官系统开发中的作用。初步研究表明，Jag1在原始胆管或导管板细胞中的表达，这些胆汁板细胞起源于发育中的小鼠和人肝脏中的肝细胞前体。我们建议通过用肝脏特异性CRE转基因线育种JAG1-LOXP小鼠，在发育中的肝脏和胆管中有选择地烧蚀Jag1。使用这种小鼠模型，我们将在没有JAG 1的情况下对导管板重塑和胆管发育进行详细研究。此外，我们将采用实时PCR和微阵列分析来确定胆管发展中Notch途径的独特下游靶标。作为一种互补策略，我们建议使用一种细胞培养方法，其中我们将从胚胎野生型和JAG1 NULL肝脏中得出双能型肝细胞细胞系。我们将评估他们对定义刺激的反应，并通过用激活的档次转染来挽救表型