Extracellular Matrix Regulation of Airway Epithelial Homeostasis

Project Summary Airway basal epithelial cells (BCs) play critical roles in lung homeostasis particularly in repair from injury reflecting their ability to differentiate into and replenish a range of mature epithelial cell types. Increasing knowledge of cell signaling and other transcriptional pathways regulating these behaviors has emerged over

recent years. However, less information is available about the effects of the physical environment, particularly the lung extracellular matrix (ECM) on BC behaviors. The ECM is increasingly recognized as affecting cell growth, differentiation, and other actions, reflecting ECM properties including protein content as well as

stiffness all of which can affect cell behaviors. Notably both BCs and ECM composition and structure can be altered in diseases, for example COPD. However, the mechanistic links between altered ECM and dysregulated BC self-renewal and differentiation is poorly understood. Better understanding will provide new

insights into normal lung epithelial homeostasis and disruption in disease and provide potential new therapeutics. To address this, we have developed novel tools and exciting preliminary data. Co-PI Dr. Ren has developed novel “inside-out” spheroid BC cultures in which the apical cell surfaces are exterior (apical-out airway

organoids, AOAO), a reverse polarity compared to traditional spheroid cultures of airway epithelial cells, and one that better reflects how the native airway interfaces with the exterior environment. In parallel, co-PI Dr. Weiss has developed a novel series of hydrogels derived from ECM of decellularized human lungs (dECM)

including those produced from airway, vascular, and alveolar-enriched compartments of both normal and diseased (COPD, IPF) human lungs. These techniques, individually and in combination, are powerful new tools that have provided novel and exciting preliminary data utilizing both normal and COPD lung-derived hydrogel

to influence lung epithelial cell growth and differentiation. The goal of the current proposal is to utilize these tools to systematically assess the effects of normal and diseased COPD ECM on relevant actions of BCs obtained from both normal and COPD lungs. Endpoint assessments will be BC self-renewal and differentiation into mature airway epithelial cells. Importantly, we

have built an outstanding collaborative team including Dr. Amy Ryan (University of Iowa) with which to achieve these goals. These studies will provide novel and important new information concerning ECM regulation of BC homeostasis that will enhance knowledge of lung injury and repair and provide potential new therapeutic

avenues for use of BCs in cell-based and other therapies.