Transcriptional Control of Liver Development

描述(由申请人提供)： 肝脏由前肠腹侧内胚层的细胞发育而来，分化为肝母细胞，并增殖到邻近的间质中，形成肝芽。这些细胞中的大多数成熟为肝细胞，但门静脉周围的一些细胞发育为导管板，从而形成胆管。在小鼠中，这之后是肝动脉的形成，从而完成了门脉三联征。肝发生缺陷是几种儿科肝病的原因。这项建议旨在培训首席调查员(PI)，使其成为专注于肝脏发育研究的研究人员，最终目的是改善这些和其他肝脏疾病。 特异性AIMS 1-3的目标是描述控制肝发生的调控网络。FOXA家族的有翼螺旋转录因子在肝脏发生前的内胚层表达，它们与许多肝脏特异基因的调控区结合。第一个特定的目的是检验FOXA1和Foxa2在肝脏的规范和进一步发育中发挥核心作用的假设。整个内胚层缺乏FOXA1和FoxA2的小鼠胚胎将被产生；初步结果表明，在缺乏这些因素的情况下，不会发生肝脏规范。FOXA在肝脏发育中的作用机制将通过蛋白质和mRNA检测技术来识别其表达依赖于FOXA1或Foxa2的肝脏转录因子。在第二个特定目标中，这些发现将通过染色质免疫沉淀和启动子微阵列分析来扩展，以确定新的FOXA1和Foxa2靶基因。第三个具体目标将通过建立转基因小鼠品系，将重点扩大到包括胆管和肝动脉发育的后期阶段，从而能够分析胆管板和胆管上皮细胞特异性基因的表达。这些数据将被用来检验这样的假设，即肝动脉形成需要来自发育中的胆管的诱导信号。 在这些研究过程中，PI将获得实验室技能、研究培训和关键试剂，这将使他能够作为一名独立的内科科学家开始工作。从这项研究和未来的研究中获得的信息将提高我们对肝脏发育的了解，并可能加强对人类肝病的诊断、治疗和预防。

DESCRIPTION (provided by applicant): The liver develops from cells of the ventral foregut endoderm which differentiate into heptoblasts and proliferate into the adjacent mesenchyme to form the liver bud. Most of these cells mature into hepatocytes, but some of those surrounding the portal veins develop into the ductal plate, which gives rise to the bile ducts. In mice, this is followed by the formation of the hepatic arteries, thereby completing the portal triad. Defects in hepatogenesis are responsible for several pediatric liver diseases. This proposal aims to train the principal investigator (PI) for a research career focused on the study of liver development with the ultimate purpose of ameliorating these and other liver disorders. The goal of Specific Aims 1-3 is to characterize the regulatory networks controlling hepatogenesis. The Foxa family of winged helix transcription factors is expressed in the endoderm immediately before the onset of hepatogenesis, and they bind to the regulatory regions of a number of liver-specific genes. The first specific aim tests the hypothesis that Foxa1 and Foxa2 play a central role in the specification and further development of the liver. Mouse embryos lacking Foxa1 and Foxa2 throughout the endoderm will be generated; preliminary results indicate that in the absence of these factors, hepatic specification does not occur. The mechanism of Foxa function in liver development will be explored using protein and mRNA detection techniques to identify liver transcription factors whose expression is dependent on Foxa1 or Foxa2. In the second specific aim, these findings will be extended using chromatin immunoprecipitation combined with promoter microarray analysis to identify novel Foxa1 and Foxa2 target genes. The third specific aim will expand the focus to include the later stages of bile duct and hepatic artery development through the derivation of a transgenic mouse line allowing the analysis of ductal plate and biliary epithelial cell-specific gene expression. This data will be used to test the hypothesis that hepatic arteriogenesis requires inductive signals from developing bile ducts. Over the course of these studies, the PI will acquire laboratory skills, research training, and critical reagents which will enable him to begin work as an independent physician-scientist. The information which will be obtained from this and future investigations will improve our understanding of liver development and may enhance the diagnosis, treatment, and prevention of liver disease in humans.