Cooperative roles of Notch and biomechanics in biliary differentiation

项目摘要 肝祖细胞的双潜能分化是肝脏发育、再生和 包括胆管缺乏和肝癌在内的疾病。胆道辨证分型的区划 肝脏汇管区附近的形态发生表明，空间隔离的微环境 信号支配着这一过程。相应地，转化生长因子β和Notch信号都被证明是 两者都被证明是胆管形成的关键介质。我们有 最近开发了一种细胞微阵列平台，使系统分析肝脏前体细胞的命运成为可能 在已定义的微环境中进行规范，特别是促进了相互作用的评估 转化生长因子β、Notch和包括细胞外基质在内的其他微环境信号之间的关系。利用这一点 此外，我们还观察到多细胞内胆管分化的一个可重复的梯度。 阵列的图案。在这些发现的基础上，我们假设机械信号在 祖细胞功能，以及细胞机械转导和Notch信号的空间模式共同作用 规范分化命运。我们将利用细胞严密控制和可调的微环境 研究多细胞构型、细胞-细胞和细胞-底物影响的微阵列平台 胆汁和肝细胞分化中的相互作用和相关的细胞机械应力。此外，我们还将 检查机械信号和Notch信号之间的串扰，包括河马的潜在参与 这些信号相互作用中的通路效应器。我们预计，这些研究将揭示出对 肝祖细胞命运的组合调控，也将建立这个平台作为研究的工具 疾病机制。

Project Summary The bipotential differentiation of liver progenitor cells is integral to liver development, regeneration, and diseases including bile duct paucity and liver cancer. The regionalization of biliary differentiation and morphogenesis near the portal region of the liver has suggested that spatially segregated microenvironmental signals govern this process. Accordingly, both TGFβ and Notch signaling have been demonstrated to be activated in the portal area, and both have been shown to be critical mediators of bile duct formation. We have recently developed a cell microarray platform that enabled the systematic analysis of liver progenitor fate specification within defined microenvironments, and in particular, facilitated the assessment of interactions between TGFβ, Notch, and other microenvironmental cues including extracellular matrix. Utilizing this approach, we additionally observed a reproducible gradient of biliary differentiation within the multicellular patterns of the array. Building on these findings, we hypothesize that mechanical signals play a role in progenitor function, and that spatial patterns of cell mechanotransduction and Notch signaling act together to regulate differentiation fate. We will exploit the tightly controlled and tunable microenvironments of the cell microarray platform to investigate the influence of multicellular geometry, cell-cell and cell-substrate interactions, and interrelated cell mechanical stress in biliary versus hepatocytic differentiation. Further, we will examine crosstalk between mechanical cues and Notch signaling, including the potential involvement of Hippo pathway effectors in these signaling interactions. We anticipate that these studies will reveal new insights into the combinatorial regulation of liver progenitor fate and will also establish this platform as a tool for studying disease mechanisms.