The role of notch signaling in the development of intrahepatic bile ducts
The role of notch signaling in the development of intrahepatic bile ducts
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DOI：
10.1053/j.gastro.2004.09.004
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发表时间：
2004-12-01
期刊：
影响因子：
29.4
通讯作者：
Chiba, T
中科院分区：
文献类型：
--
作者：
Kodama, Y;Hijikata, M;Chiba, T
背景和目标：Notch配体Jagged 1的突变导致Alagille综合征（AGS），这是一种以肝内胆管缺乏（IHBD）为特征的疾病。然而，Notch信号通路对IHBD形成的作用机制仍然未知。在这里，我们研究了Notch信号在IHBD发展中的作用。研究方法：通过半定量逆转录聚合酶链反应（PT-PCR）、免疫印迹和免疫组化分析小鼠肝脏发育过程中Jagged 1、Notch 2和Hes 1的表达模式。研究了Hes 1基因敲除小鼠与野生型小鼠的肝细胞成熟水平和IHBD发育。Jagged：1对胆管分化的影响通过使用体外2-细胞共培养系统与WB-F344细胞（来源于正常成年大鼠肝脏的细胞系）进行评估。结果：Jagged：1在新生期门脉间质中表达。在同一时期，Notch 2和Hes 1的表达观察到邻近的Jagged 1阳性细胞的胆管上皮细胞。在胆管板重塑过程中，Notch 2和Hes 1仅在形成管状结构的胆管上皮细胞中上调。相反，在Hes 1基因敲除小鼠中完全不存在IHBD的肾小管形成。与稳定过表达Jagged 1的BaIb 3 T3细胞共培养可诱导WB-F344细胞中Hes 1启动子的反式激活，并增加胆汁谱系标记物（例如细胞角蛋白-19和γ-谷氨酰转肽酶）的表达。结论：我们的研究结果表明，Notch信号传导在胆管上皮细胞的分化中具有重要作用，并且在IHBD发育过程中对其小管形成至关重要。
Background & Aims: Mutations in Jagged1, a Notch Iigand, cause Alagille syndrome (AGS), a disorder characterized by a paucity of intrahepatic bile ducts (IHBD). The mechanism underlying the contribution of the Notch signaling pathway to IHBD formation, however, remains unknown. Here we investigated the role of Notch signaling in IHBD development. Methods: The expression patterns of Jagged1, Notch2, and Hes1 during mouse liver development were analyzed by semiquantitative reverse-transcription polymerase chain reaction (PT-PCR), immunoblot, and immunohistochemistry. The hepatocyte maturation level and IHBD development were studied in Hes1 null mice in comparison with wild-type mice. The effect of Jagged:1 on biliary differentiation was assessed by using an in vitro 2-cell coculture system with WB-F344 cells, a cell line derived from normal adult rat liver. Results: Jagged:1 was expressed in the portal mesenchyme during the neonatal period. During the same period, Notch2 and Hes1 expression was observed in the biliary epithelial cells adjacent to the Jagged1-positive cells. During ductal plate remodeling, Notch2 and Hes1 were up-regulated exclusively in the biliary epithelial cells that form tubular structures. In contrast, the tubular formation of IHBD was completely absent in Hes1 null mice. Coculture with BaIb3T3 cells stably overexpressing Jagged1 induced transactivation of the Hes1 promoter and increased expression of biliary lineage markers, such as cytokeratin-19 and gamma-glutamyl transpeptidase, in WB-F344 cells. Conclusions: Our results suggest that Notch signaling has an important role in the differentiation of biliary epithelial cells and is essential for their tubular formation during IHBD development.