Microenvironmental Control of Liver Progenitor Cell Differentiation and Spatial Patterning

项目摘要 肝祖细胞向肝细胞和胆管上皮细胞（胆管细胞）的双能分化 是肝脏发育、再生和包括胆管缺乏和肝癌在内的疾病的组成部分。在 特别是，最常见的先天性肝病与胆管功能障碍有关。除了 在胚胎发育过程中的发育过程中，导管形态发生也发生在成体肝脏中， 对严重和慢性损伤的反应。这些所谓的小管反应表现出高度可变的分化 模式，虽然这些反应显着有助于肝脏的增殖反应， 仍然没有很好的特征。值得注意的是，在成人肝脏中，胆管增生集中在汇管区附近 静脉区域，类似于发育过程中胆管的形成。尽管进行了大量的研究工作， 肝脏发育和再生的结构复杂性和动态性限制了对肝脏发育和再生的全面研究。 对疾病机制的理解以及新治疗方案的进展。长期 该项目的目标是开发互补的二维和三维工程组织 可以应用于研究肝祖细胞分化机制的平台， 目前无法用现有的细胞培养系统和动物模型获得。为此，我们将 追求以下研究目标，这是专门针对解构结合 生化和生物力学信号在肝祖细胞命运特化中影响。在目标1中，我们 利用细胞微阵列平台研究Notch信号和细胞的空间梯度的影响， 祖细胞分化中的机械应力。我们的方法将能够独立控制细胞- 细胞相互作用，由多细胞几何结构和特定的外源性微环境信号定义 在阵列平台中呈现。在目标2中，我们将开发和利用三维微组织 文化平台，系统地研究三维几何的影响，并确定如何 不同的多细胞几何形状调节分化模式。这些研究工作将建立 微尺度组织工程工具，使控制的介绍和系统的扰动， 微环境信号。在目标3中，我们将把我们的研究扩展到直接分析人类 通过整合人诱导多能干（iPS）细胞衍生的肝分化机制 肝祖细胞总的来说，我们的方法将允许对肝脏的机制进行新的研究。 祖细胞分化，包括细胞分化的组合影响的独特检查， 机械应力梯度和Notch信号。此外，我们设想这些平台是可推广的， 并且可以作为基础生物学研究和治疗的使能技术来实施。 在广泛的细胞和组织背景下的开发努力。

Project Summary The bipotential differentiation of liver progenitor cells to hepatocytes and biliary epithelial cells (cholangiocytes) is integral to liver development, regeneration, and diseases including bile duct paucity and liver cancer. In particular, the most common congenital liver diseases are associated with bile duct dysfunction. In addition to the developmental processes during embryogenesis, duct morphogenesis also occurs in the adult liver in response to severe and chronic injury. These so-called ductular reactions exhibit highly variable differentiation patterns, and although these reactions significantly contribute to the proliferative responses in the liver, they remain poorly characterized. Notably, ductular proliferations in the adult liver are concentrated near the portal vein region, similar to the formation of bile ducts during development. Despite substantial research efforts, the structural complexity and dynamic nature of liver development and regeneration has limited the comprehensive understanding of disease mechanisms as well as the advancement of new therapeutic options. The long-term goal of this project is to develop complementary two-dimensional and three-dimensional engineered tissue platforms that can be applied towards the investigation of liver progenitor cell differentiation mechanisms that are presently inaccessible with current cell culture systems and animal models. Towards this end, we will pursue the following research objectives, which are specifically targeted towards deconstructing the combined influence of biochemical and biomechanical signals in liver progenitor cell fate specification. In Aim 1, we will utilize a cell microarray platform to investigate the influence of spatial gradients of Notch signaling and cell mechanical stresses in progenitor cell differentiation. Our approach will enable the independent control of cell- cell interactions, defined by multicellular geometry, and specific exogenous microenvironmental signals presented within the array platform. In Aim 2, we will develop and utilize a three-dimensional microtissue culture platform to systematically investigate the effects of three-dimensional geometry and determine how distinct multicellular geometries regulate differentiation patterns. These research efforts will establish microscale tissue engineering tools that enable the controlled presentation and systematic perturbation of a range of microenvironmental signals. In Aim 3, we will extend our studies towards the direct analysis of human liver differentiation mechanisms through the integration of human induced pluripotent stem (iPS) cell-derived liver progenitor cells. Collectively, our approach will allow for novel studies into the mechanisms of liver progenitor cell differentiation, including the unique examination of the combinatorial influence of cell mechanical stress gradients and Notch signaling. Further, we envision that these platforms are generalizable, and could be implemented as enabling technologies for fundamental biological investigation and therapeutic development efforts for a broad range of cell and tissue contexts.