2024 AIChE Annual Meeting
(64f) In Situ Rheology of Mucus on Live Airway Epithelial Cell Cultures
Authors
Liegeois, M., University of California San Francisco
Milla, C., Stanford University
Fahy, J., University of California San Francisco
Mucus that lines the lungs acts as the primary defense against inhaled foreign particles and infectious agents by trapping the invaders and preventing them from penetrating the tissue layer. Effective mucus clearance, and thus removal of the trapped invaders is vital for healthy airway function. Changes in mucus rheology can inhibit mucus transport and result in a breakdown of mucus clearance. The rheological properties of mucus, e.g. viscosity and elasticity, can vary dramatically with diseases such as asthma and cystic fibrosis (CF), where thickened and concentrated mucus tends to build up and occlude the airway. Characterization of mucus rheology in health and disease is crucial to understanding underlying mechanisms of disease progression and developing targeted therapeutic strategies to address muco-obstructive disorders. Thus far, rheological studies of mucus have been limited by difficulty of collection, small sample volumes, and changes in properties due to collection and handling procedures. To address these limitations, we present a custom device to measure mucus rheology in situ directly on live human epithelial cell cultures for the first time. Human airway epithelial cells (HAECs) were grown at air-liquid interface (ALI), mimicking the airway surface environment. During rheological experiments, we maintained the cells at ALI and used a micron-scale magnetic wire (microwire) to probe the properties of the secreted mucus layer. The microwire was placed on the mucus layer of the live HAEC cultures. Electromagnetic coils were used to apply a magnetic force on the microwire, and the resulting motion of the microwire in the mucus was imaged. The relationship between the applied force and measured displacement was used to determine the viscoelasticity of the mucus layer. We used this instrument to conduct creep compliance measurements of mucus on live cultures from healthy and CF donors. Additionally, we examined the change in mucus properties with inflammatory stimulation by cytokine interleukin-13, associated with asthma, and with CF treatment of a combination of elexacaftor, tezacaftor, and ivacaftor (ETI). With these studies, we demonstrate the ability to quantify changes in mucus viscoelasticity with various disease models and drug treatments, giving us unique insight into the mechanisms of pathologic mucus production. Our work demonstrates the power of this in situ rheology method to probe the relationship between epithelial cell physiology and the secreted mucus rheology.