Mechanobiology of Epithelial Monolayers under Shear Loading

细胞之间的机械相互作用控制着生命的基本过程。 然而，我们对这些机械效应的理解还不足以解释多细胞生物学、组织发育和疾病进展中的许多重要问题，我们已经知道这些问题依赖于细胞间的力。细胞之间附着（粘连）的维持和周转对于细胞如何在器官的不同部分之间形成屏障至关重要。 粘附对于伤口愈合是重要的，并且细胞-细胞粘附的破坏也是癌症转移的前兆。器官形成、伤口愈合和癌症转移涉及大的变形和力的产生，但是细胞粘附的动态调节的潜在机制、细胞如何滑动或剪切通过彼此、或者细胞-细胞粘附在机械载荷下如何起作用还不清楚。研究目标是了解组织如何分布和响应通过细胞-细胞连接传递的剪切力。 该项目将测试剪切如何改变集体细胞行为和细胞结构的重组。这些变化与细胞的生物力学特性相关联，并最终调节组织完整性、屏障功能和体内平衡。 研究成果将被纳入模块教学基本工程和生物学课程，并在我们的实验室本科研究经验的发展。该研究结合了定制的微制造细胞培养平台，力传感和位移驱动，机械分析和细胞生物学方法，如药理学抑制剂和敲除细胞系。我们研究外部施加和细胞产生的力量如何动态修改集体细胞行为，以响应剪切破坏。生理发育表现出缓慢的变形，而损伤发生在一个更快的时间尺度上，因此，我们测试的想法，集体细胞mechanoresponse不仅取决于负载和组织刚度，但也施加的负载率。我们将测试的想法，动态细胞-细胞粘附是由蛋白质捕捉力和速率依赖性的债券。这项工作将提供新的平台技术，用于上皮组织的机械操作和观察，并测试跨细胞-细胞粘附和细胞骨架的力传递和细胞-细胞通信的新模型。在这项工作中获得的见解将增加我们对上皮细胞稳态的理解，上皮细胞稳态是每个器官系统正常屏障功能的基础。

Mechanical interactions between cells govern the basic processes of life. We don't understand these mechanical effects enough, however, to explain many of the important questions in multicellular biology, tissue development, and disease progression that we already know are dependent on intercellular forces. Maintenance and turnover of the attachments between cells (adhesions) is critical to how cells can form a barrier between different parts of organs. Adhesion is important to wound healing, and also disruption of cell-cell adhesion is a precursor to cancer metastasis. Organ formation, wound healing and cancer metastasis involve large deformations and force generation, yet the mechanisms underlying the dynamic regulation of cell adhesions, how cells slide or shear past one another, or how cell-cell adhesions function under mechanical loading are not yet understood. The research goal is to understand how tissues distribute and respond to shear force transmitted through cell-cell junctions. The project will test how shear modifies collective cell behavior and reorganization of cellular architecture. Such changes are coupled to the biomechanical properties of cells and ultimately regulate tissue integrity, barrier functions and homeostasis. The research results will be incorporated into modules for teaching basic Engineering and Biology courses, and the development of undergraduate research experiences within our laboratories. The PIs actively participate in community outreach and research experiences for teachers and under-represented students.This research combines custom micro-fabricated cell culture platforms with force-sensing and displacement-actuation with mechanical analyses and cell biological methods such as pharmacological inhibitors and knockout cell lines. We study how externally applied and cell-generated forces dynamically modify collective cell behavior in response to shear disruption. Physiological development exhibits slow deformations while injury occurs on a faster timescale, thus we test the idea that collective cell mechanoresponse depends not only on load and tissue rigidity, but also on the applied loading rate. We will test the idea that dynamic cell-cell adhesion is governed by protein catch bonds with force- and rate-dependence. This work will deliver new platform technologies for mechanical manipulation and observation of epithelial tissues and test new models of force transfer and cell-cell communications across cell-cell adhesions and the cytoskeleton. Insights gained in this work will increase our understanding of epithelial homeostasis which underlies normal barrier function in each organ system.