Mechanical and Genetic Regulation of Multi-Timescale Airway Smooth Muscle Contractions that Drive Lung Development

胚胎肺发育是一个知之甚少的过程，涉及细胞生长和组织的协调，以产生对生存至关重要的功能呼吸道。最近，人们发现，在胚胎发育期间，围绕着发育中的呼吸道的平滑肌的收缩在新的呼吸道的分支中起着至关重要的作用。两种类型的平滑肌收缩--快速和缓慢--发生在发育中的肺中。这项研究将确定快慢气道平滑肌收缩之间的联系，它们在气道分支中的作用，以及这些过程背后的细胞活动。更深入地了解导致呼吸道生长的机制对于了解总体上的肺发育以及预测、预防和修复结构性出生缺陷具有重要意义。这项研究中创建的研究肺发育的方法可以应用于肌肉收缩改变发育的其他器官的发育。这个项目将为本科生和研究生提供发育机制方面的培训基础，并通过创建单元和教案来吸引和启发STEM领域的学生，以便向中学传播有关微流体治疗疾病的方法。空间上不协调的快速蠕动收缩和新发现的协调缓慢的呼吸道平滑肌收缩在肺中都很活跃，并受到呼吸道内流体压力的调节。这项工作的重点是记录多个时间和长度尺度上的气道平滑肌收缩的动力学，并发展对其分子调节机制的理解。为了探索这些事件及其潜在的分子机制，本项目的目标是：(1)使用视频显微镜来表征多时间尺度的收缩动力学；(2)利用免疫组织化学和腺病毒技术，确定体外收缩蛋白的作用；以及(3)利用新开发的微流控血管体外平台，确定力学在诱导收缩事件中的作用。通过了解这些发育机制，我们可以利用它们作为工具来指导再生医学组织的从头生产，并使未来的研究能够询问特定的遗传和/或结构因素的作用。

Embryonic lung development is a poorly understood process involving the coordination of cellular growth and organization to give rise to functional airways that are critical for survival. Recently, contractions of the smooth muscle that surrounds the developing airways was discovered to have a critical role in the branching of new airways during embryonic development. Two types of smooth muscle contractions - fast and slow - occur in the developing lung. This research will determine the connection between fast and slow airway smooth muscle contractions, their role in airway branching, and the cellular activity underlying these processes. Deeper understanding of the mechanisms that cause the growth of the airways is of importance for understanding lung development in general and also for predicting, preventing, and repairing structural birth defects. The methods created in this research to study lung development could have application to development of other organs where muscular contractions change development. This project will offer a basis for undergraduate and graduate training in the mechanics of development and serve to engage and inspire students in the STEM fields with the creation of modules and lesson plans for dissemination to secondary schools about microfluidic approaches to treat disease.Spatially uncoordinated, fast peristaltic contractions and newly identified, coordinated slow contractions of the airway smooth muscle are both active in the lung and regulated by the fluid pressure within the airways. This work focuses on documenting the kinetics of airway smooth muscle contractions across multiple time and length scales and developing an understanding of its molecular regulators. To explore these events and the underlying molecular mechanisms, the objectives of this project are: (1) use video microscopy to characterize the multi-timescale contraction kinetics; (2) determine the role of contractile proteins ex vivo, utilizing immunohistochemical and adenoviral techniques; and, (3) determine the role of mechanics on inducing contraction events, utilizing a newly developed microfluidic smooth muscle in vitro platform. By understanding these developmental mechanisms, we can use them as tools to guide de novo production of tissue for regenerative medicine and enable future studies interrogating the role of specific genetic and/or structural factors.