CAREER: Directing Epithelial-Mesenchymal Tissue Self-Structuring and Remodeling With Multi-scale Mechanical Interactions and Principles of Mechanobiology

美国国家科学基金会教师早期职业发展（Career）计划的目标是建立一个综合研究和教育计划，以了解物理力量如何促进上皮-间质结构（EMS）的初始形成和后期变化，如皮肤的双层表皮和真皮结构。这些结构存在于大多数身体组织中，它们对组织健康至关重要。在组织形成过程中，细胞与细胞之间以及细胞与细胞外基质之间的相互作用结合在一起，产生了具有EMS的有组织、有功能的组织。然而，在生命的后期，这些组织在受伤、疾病或衰老时自我再生的能力有限。指导组织自结构和重塑用于医学目的的努力正在取得进展，但由于不知道细胞和基质之间的相互作用如何在生物化学和机械上协调以产生健康的组织，它们仍然受到阻碍。这些交互是复杂的，产生的行为不能用简单的方法轻易理解。这项研究将提供一个基本的计算机模型，可以将来自不同实验的数据和观察结果整合到一个统一的图像中，从而可以理解机械生物学的基本原理并用于帮助控制组织形成和重塑。该项目有望在皮肤上皮-间质相互作用中的物理作用方面产生新的发现和见解。所获得的知识和开发的工具也可能广泛适用于发生EMS的身体其他部位，如血管、肺、肠和肾脏。该项目的更广泛目标包括提高公众对数学、工程和计算机建模如何用于简化复杂生物过程的认识、理解和兴奋，特别是那些涉及机械力的生物过程。该项目的研究成果将与爱荷华大学外展项目合作，纳入K-12年级年轻学生的学习模块。研究还将纳入本科生和研究生的生物医学工程课程，并纳入可公开访问和免费下载的多媒体iBook，其中包含活细胞成像和计算机模拟。角质形成细胞和成纤维细胞的体外延时成像实验将用于开发和调整多尺度计算模型，以理解和预测物理力如何驱动皮肤中EMS的自结构和重塑。这将通过：(1)量化底物刚度、成分和负载环境对机械传感和角质形成细胞自组装过程的影响；(2)建立基于机械网络的机械感测角质形成细胞模型，该模型与现有的多尺度模型相结合；(3)验证角化细胞和真皮成纤维细胞之间的机械串扰影响工程皮肤系统的自结构和EMS形成的假设；(4)将细胞模型扩展到包括3D成纤维细胞驱动的重塑。

The goal of this NSF Faculty Early Career Development (CAREER) Program grant is to establish an integrated research and education program centered on understanding how physical forces contribute to the initial formation and later changes in epithelial-mesenchymal structures (EMS), such the bi-layered epidermal and dermal structure of skin. These structures are present in most body tissues and they are critical to tissue health. During the process of tissue formation, cell-to-cell and cell-to-extracellular matrix interactions combine to produce organized, functional tissues with EMS. Later in life, however, these tissues have limited capacity to regenerate themselves in response to injury, disease, or aging. Efforts to direct tissue self-structuring and remodeling for medical purposes are progressing, but they are still hampered by not knowing how the interactions between cells and matrix are coordinated biochemically and mechanically to produce a healthy tissue. These interactions are complex and produce behaviors that cannot be easily understood using a simple approach. This research will provide an essential computer model that can incorporate data and observations from different experiments into a unified picture so that basic principles of mechanobiology can be understood and used to help control tissue formation and remodeling. The project is expected to produce new discoveries and insights on the role of physical forces in epithelial-mesenchymal interactions in skin. The knowledge gained and tools developed may also be broadly applicable and useful to other parts of the body where EMS occur, such as blood vessels, lungs, intestines, and kidneys. Broader goals of the project include generating more public awareness, understanding, and excitement for how mathematics, engineering, and computer modeling can be used to simplify complex biological processes, particularly those that involve mechanical forces. Research findings from this project will be put into learning modules accessible for young students from K-12 in collaboration with the University of Iowa outreach programs. Research will also be put into undergraduate and graduate biomedical engineering courses, and into a publically accessible and freely downloadable multimedia iBook with live cell imaging and computer simulations.In vitro time-lapse imaging experiments on keratinocytes and fibroblasts will be used to develop and tune a multi-scale computational model for understanding and predicting how physical forces drive self-structuring and remodeling of EMS in skin. This will be accomplished by: (1) quantifying the effect of substrate stiffness, composition, & loading environment on mechanosensing and the self-assembly process of keratinocytes; (2) developing a mechanistic network-based model of mechanosensing keratinocytes that interfaces with an existent multi-scale model; (3) testing the hypothesis that mechanical crosstalk between keratinocytes and dermal fibroblasts influences self-structuring and EMS formation in an engineered skin system; and (4) extending the cell model to include 3D fibroblast-driven remodeling.