Mechanical compaction directly modulates the dynamics of bile canaliculi formation
Mechanical compaction directly modulates the dynamics of bile canaliculi formation
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机械压实直接调节胆小管形成的动力学
DOI：
10.1039/c2ib20229h
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发表时间：
2013-01-01
影响因子：
2.5
通讯作者：
Yu, Hanry
中科院分区：
文献类型：
--
作者：
Wang, Yan;Toh, Yi-Chin;Yu, Hanry
动态平衡压力驱动压实是多细胞生物体中普遍存在的一种机械力，对维持多细胞组织的完整性和功能具有重要意义。以前的无细胞生物化学模型已经证明，致密力和组织结构功能之间存在着相互作用，如细胞与细胞之间的黏附。然而，其在生理组织功能中的作用尚未得到直接证实。在这里，我们使用胆小管(BC)作为肝脏中多细胞功能结构的生理学例子，并使用一种新型的3D微流控肝细胞培养系统来提供一个前所未有的机会来在3D生理模拟环境中实验调节初级肝细胞聚集体的致密状态。机械压实改变了肝细胞聚集体的物理属性，包括细胞形状、细胞堆积密度和细胞与细胞的接触面积，但不损害肝细胞的重塑和功能能力。结构和功能极性的表征表明，致密的肝细胞集合体中BC的形成最早在播种后12小时就被加速；而非紧凑的对照需要48小时才能形成功能性BC。进一步的动态免疫荧光成像和基因表达谱显示，致密化加速BC的形成伴随着肌动蛋白细胞骨架重构动力学和肝细胞核因子4α和Annexin A2转录水平的变化。我们的报告不仅为体外肝病研究提供了一种模拟BC形成的新策略，而且首次展示了动态平衡压力驱动的致密力直接耦合到更高阶的多细胞功能。
Homeostatic pressure-driven compaction is a ubiquitous mechanical force in multicellular organisms and is proposed to be important in the maintenance of multicellular tissue integrity and function. Previous cell-free biochemical models have demonstrated that there are cross-talks between compaction forces and tissue structural functions, such as cell-cell adhesion. However, its involvement in physiological tissue function has yet to be directly demonstrated. Here, we use the bile canaliculus (BC) as a physiological example of a multicellular functional structure in the liver, and employ a novel 3D microfluidic hepatocyte culture system to provide an unprecedented opportunity to experimentally modulate the compaction states of primary hepatocyte aggregates in a 3D physiological-mimicking environment. Mechanical compaction alters the physical attributes of the hepatocyte aggregates, including cell shape, cell packing density and cell-cell contact area, but does not impair the hepatocytes' remodeling and functional capabilities. Characterization of structural and functional polarity shows that BC formation in compact hepatocyte aggregates is accelerated to as early as 12 hours post-seeding; whereas non-compact control requires 48 hours for functional BC formation. Further dynamic immunofluorescence imaging and gene expression profiling reveal that compaction accelerated BC formation is accompanied by changes in actin cytoskeleton remodeling dynamics and transcriptional levels of hepatic nuclear factor 4 alpha and Annexin A2. Our report not only provides a novel strategy of modeling BC formation for in vitro hepatology research, but also shows a first instance that homeostatic pressure-driven compaction force is directly coupled to the higher-order multicellular functions.