Mechanisms of Bile Duct Morphogenesis

摘要 这项建议的重点是胆道系统的形态发生，胆管是 胆汁从肝细胞到肠道的运输。胆管功能障碍 沿着其错综复杂的分支结构的点可能是发病率和死亡率的来源， 而重建正常的胆道完整性对于损伤的恢复至关重要。这个 本建议书中描述的实验将深入了解连接是如何 沿着整个胆道树建立，描绘了通过 缺口-一种其缺陷导致人类胆管缺陷的途径-调节 肝脏发育，并确定这一途径在成人胆汁功能中的作用 风管。 这项研究的长期目标是了解肝脏如何实现和 保持了它的三维架构。拟议的实验将使用 CRE/LOX技术和实时成像在胆道多参数检测中的应用 活体形态发生：肝外-肝内胆管连接处的形成 胆管-小管连接处的形成和胆管细胞极性的建立 和小管形成。该提案的一个中心目标是检验诺奇 信号通过启动细胞“小管生成程序”来控制胆管的发育。 这一进程的特定候选调解人将接受测试，以确定他们在 体外小管生成。此外，还将进行研究，以检查Notch如何 信号与其他已知的胆管发育调节因子(如 HNF1B、HNF6、TGFb)。最后，提出了验证该假说的实验。 Notch信号在一生中继续对肝脏生物学产生影响，通过 维持导管细胞的完整性并在空间上组织对损伤的反应。

Abstract This proposal is focused on morphogenesis of the biliary system, the conduit for transport of bile from hepatocytes to the intestine. Dysfunction of the bile ducts at any point along its intricate branched structure can be a source of morbidity and mortality, and re-establishment of normal biliary integrity is essential for recovery from injury. The experiments described in this proposal will provide insight into how connectivity is established along the entirety of the biliary tree, delineate the mechanisms by which Notch - a pathway whose deficiency causes bile duct deficiency in humans - regulates liver development, and determine the role of this pathway in the function of adult bile ducts. The long-term objective of this research is to understand how the liver achieves and maintains its three dimensional architecture. The proposed experiments will employ Cre/lox technology and real-time imaging to examine several parameters of biliary morphogenesis in vivo: formation of the extrahepatic-intrahepatic biliary junction, formation of the ductal-canalicular junction, and the establishment of biliary cell polarity and tubule formation. A central goal of the proposal is to test the hypothesis that Notch signaling controls bile duct development by initiating a cellular "tubulogenesis program," and specific candidate mediators of this process will be tested for their role in tubulogenesis in vitro. In addition, studies will be performed to examine how Notch signals are coordinated with other known regulators of bile duct development (e.g. HNF1b, HNF6, TGFb). Finally, experiments are proposed that will test the hypothesis that Notch signaling continues to exert an effect on liver biology throughout life, by maintaining ductal cell integrity and spatially organizing the response to injury.