Collaborative Research: Mechanobiology of Fiber Geometry-RhoGTPase Crosstalk at the Leading Edge of Cells Crawling on Fibers

细胞在由纤维蛋白组成的复杂三维环境中运动。 细胞选择移动方向的第一步是通过拉动纤维来感知其环境。 这开始了所谓的“细胞收缩性”。 在正常或患病组织中，随机分布或以特定模式分布的不同直径的纤维如何实现收缩性目前尚不清楚。了解细胞和接触的纤维之间的第一次感觉相互作用对于细胞如何侵入纤维组织非常重要，例如当癌细胞离开肿瘤时，或者纤维上的细胞向伤口部位定向迁移时。我们对细胞迁移的了解大部分源于在二维平面基底上进行的经典研究，或者最近使用复杂凝胶的经典研究。 这两种方法都不允许研究细胞-纤维相互作用。 这项研究将解决量化细胞-纤维相互作用的需求，以了解伤口愈合和疾病期间的细胞迁移。在这项合作研究中，通过结合纳米纤维制造、细胞信号生物传感器和细胞力学方面的最先进技术，我们将能够看到细胞内部并确定帮助细胞沿着纤维迁移的决策机制。 PI 将与当地社区大学的教师合作，在实验室对他们进行培训，以便他们能够开发教材。 这将为社区学院的学生创造研究机会。该项目将定义细胞与纤维相互作用时的力学生物学状态。具体来说，我们将揭示细胞形成突起并在纤维上迁移时的 RhoGTPase 信号传导（RhoA、Rac1 和 CdC42）。这些分子在细胞特定区域的相互作用、定位和求和定义了迁移模式，其在 2D 和 3D 中已被证明是不同的。为了确定纤维上细胞中这些蛋白质的活性图，我们将设计不同直径（纳米-微米）的纤维网络，以对齐和随机配置分布，表示有利和抗侵入条件。通过这样做，我们将能够精确定位细胞拉动纤维并对纤维施加力时 RhoGTPase 的空间和时间激活图。机械生物学力定量-生物传感器激活将开发关于细胞迁移到不断变化的纤维环境的可塑性的新知识，就像在体内遇到的那样。将跨越广泛空间（纳米-微米）和时间（秒-小时）尺度的基于粘附受体的信号传导与迁移和力调节联系起来，将为入侵驱动的细胞迁移提供新知识，从而为药物发现和开发开辟新方向。该奖项反映了 NSF 的法定使命，并通过使用基金会的智力价值和更广泛的影响审查标准进行评估，被认为值得支持。

Cells move in a complex three-dimensional environment composed of fibrous proteins. A first step for a cell in choosing a direction to move is to sense its environment by tugging at the fibers. This starts what is called 'cell contractility.' How contractility is achieved on fibers of varying diameters distributed randomly or in specific patterns, in normal or diseased tissues, is mostly unknown. Understanding the first sensory interactions between a cell and a contacted fiber is important to how cells invade a fibrous tissue, such as when cancer cells leave a tumor, or in directed migration of cells on fibers towards a wound site. Most of what we know about cell migration stems from classical studies conducted on 2D flat substrates or, more recently, using complex gels. Neither approach allows the studying of cell-fiber interactions. This research will address the need to quantify cell-fiber interactions to understand cell migration during wound healing and disease. In this collaborative research, by combining state-of-art technologies in nanofiber manufacturing, cell signaling biosensors, and cell mechanics, we will be able to see inside the cell and determine the decision mechanisms that help cells migrate along fibers. The PI will work with faculty at a local community college to train them in the laboratory so that they can develop educational materials. This will create research opportunities for community college students.This project will define the mechanobiological state of a cell as it interacts with fibers. Specifically, we will reveal RhoGTPase signaling (RhoA, Rac1, and CdC42) as cells form protrusions and migrate on fibers. The interplay, localization, and summation of these molecules at specific regions of the cell define the mode of migration, which has been shown to be different in 2 and 3D. To determine the activity maps of these proteins in cells on fibers, we will design fiber networks of varying diameters (nanometers-microns) distributed in aligned and random configurations signifying pro- and anti-invasive conditions. In doing so, we will be able to pinpoint spatial and temporal activation maps of RhoGTPase's as cells tug and exert forces on fibers. The mechanobiological force quantitation-biosensor activation will develop new knowledge in the plasticity of cell migration to changing fibrous environments, as would be encountered in vivo. Linking adhesion receptor-based signaling spanning a wide range of spatial (nanometers-microns) and temporal (seconds-hours) scales with migration and force modulation will provide new knowledge in invasion-driven cell migration, thus opening new directions in drug discovery and development.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.