Cooperative roles of Notch and biomechanics in biliary differentiation

项目摘要 肝祖细胞的双能分化是肝发育、再生和分化的组成部分。 包括胆管缺如和肝癌的疾病。胆管分化的区域化和 肝门区附近的形态发生表明，空间分离的微环境 信号控制着这个过程。因此，TGFβ和Notch信号传导已被证明是相互作用的。 在汇管区被激活，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，能够系统分析肝祖细胞的命运 定义的微环境内的规范，特别是促进了交互作用的评估 TGFβ、Notch和其他微环境因子（包括细胞外基质）之间的关系。利用该 方法，我们还观察到一个可重复的梯度内胆管分化的多细胞 阵列的模式。基于这些发现，我们假设机械信号在 祖细胞功能，以及细胞机械转导和Notch信号传导空间模式共同作用， 调节分化命运。我们将利用细胞中严格控制和可调的微环境 微阵列平台，以研究多细胞几何形状、细胞-细胞和细胞-基质的影响 相互作用和相关的细胞机械应力在胆汁与肝细胞分化。此外，我们将 检查机械线索和Notch信号之间的串扰，包括Hippo的潜在参与 在这些信号相互作用的途径效应。我们预计，这些研究将揭示新的见解， 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.