PDF(Pubmed)
Abstract：
Lumenogenesis within the epiblast represents a critical step in early human development, priming the embryo for future specification and patterning events. However, little is known about the specific mechanisms that drive this process due to the inability to study the early embryo in vivo. While human pluripotent stem cell (hPSC)-based models recapitulate many aspects of the human epiblast, most approaches for generating these 3D structures rely on ill-defined, reconstituted basement membrane matrices. Here, we designed synthetic, nonadhesive polyethylene glycol (PEG) hydrogel matrices to better understand the role of matrix mechanical cues in iPSC morphogenesis, specifically elastic modulus. First, we identified a narrow range of hydrogel moduli that were conducive to the hPSC viability, pluripotency, and differentiation. We then used this platform to investigate the effects of the hydrogel modulus on lumenogenesis, finding that matrices of intermediate stiffness yielded the most epiblast-like aggregates. Conversely, stiffer matrices impeded lumen formation and apico-basal polarization, while the softest matrices yielded polarized but aberrant structures. Our approach offers a simple, modular platform for modeling the human epiblast and investigating the role of matrix cues in its morphogenesis.
摘要：
外胚层内的管腔生成代表了人类早期发育的关键步骤，为未来的规范和模式事件启动胚胎。然而,由于无法在体内研究早期胚胎，因此对驱动这一过程的具体机制知之甚少。虽然基于人类多能干细胞（hPSC）的模型概括了人类表皮母细胞的许多方面，生成这些3D结构的大多数方法都依赖于不明确的定义，重组基底膜基质。这里,我们设计了合成的，非粘附性聚乙二醇（PEG）水凝胶基质，以更好地了解基质机械线索在iPSC形态发生中的作用，特别是弹性模量。首先,我们确定了一个窄范围的水凝胶模量，有利于hPSC活力，多能性,和差异化。然后我们使用这个平台来研究水凝胶模量对腔生成的影响，发现中等刚度的基质产生了最像上胚层的聚集体。相反，较硬的基质阻碍了管腔形成和顶端基底极化，而最软的基质产生极化但异常的结构。我们的方法提供了一个简单的，用于对人类上胚层建模和研究基质线索在其形态发生中的作用的模块化平台。
