THE ROLE OF ECM MECHANICS IN REGULATING CAPILLARY MORPHOGENESIS

这个子项目是许多研究子项目中利用 资源由NIH/NCRR资助的中心拨款提供。子项目和 调查员(PI)可能从NIH的另一个来源获得了主要资金， 并因此可以在其他清晰的条目中表示。列出的机构是 该中心不一定是调查人员的机构。 细胞外基质机制对二维细胞反应(如黏附、扩散、运动、增殖甚至分化)的重要性得到了广泛的认识和很好的描述。然而，内在机械信号对细胞在3-D培养中的长期表型反应的影响仍未明确，这些表型变化的分子机制也是如此。在3-D中将细胞表型变化与底物力学联系起来的努力在一定程度上受到了缺乏合适材料系统的阻碍。理想情况下，一个合适的材料系统应该提供可预测地调整底物机械性能的手段，而不依赖于黏附配体密度和蛋白分解敏感性。除了材料的限制外，由于缺乏合适的方法来评估局部细胞-材料界面的力学性质，在3-D中剖析ECM力学对细胞功能的影响的努力一直受到阻碍。相反，大多数研究人员选择使用材料的弹性和粘弹性属性的整体测量，并将这些与细胞功能相关联；不幸的是，这些不能充分描述当地的微环境。我们提出利用一种独特的基于聚乙二醇和纤维蛋白原的生物合成杂化水凝胶。此外，我们还建议开发新的方法来测量这种材料的局部力学性能。以下三个具体目标构成了拟议的研究。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. The importance of ECM mechanics on 2-D cell responses (e.g., adhesion, spreading, motility, proliferation, and even differentiation) is widely recognized and well characterized. However, the effects of intrinsic mechanical cues on longer-term phenotypic responses of cells in 3-D culture remain undefined, as do the molecular mechanisms underlying these phenotypic changes. Efforts to relate changes in cell phenotype with substrate mechanics in 3-D have been hindered in part by the lack of suitable material systems. Ideally, a suitable material system should provide the means to predictably tune substrate mechanical properties independently from adhesion ligand density and proteolytic sensitivity. In addition to material limitations, efforts to dissect the influence of ECM mechanics on cell function in 3-D have been hampered by the lack of suitable methods to assess mechanical properties at the local cell-material interface. Most researchers have instead chosen to utilize bulk measurements of a material's elastic and viscoelastic properties and to correlate these with cell function; unfortunately, these do not adequately depict the local microenvironment. We proposed to utilize a unique biosynthetic hybrid hydrogel based on poly(ethylene glycol) and fibrinogen. Furthermore, we proposed to develop novel methodologies to measure the local mechanical properties this material. The following three specific aims constitute the proposed study.