Development of Experimental and Computational Tools to Investigate the Mechanobiology of Cellular Senescence in Pulmonary Fibrosis

Idiopathic pulmonary fibrosis (IPF) is a devastating condition of scar tissue buildup in the lung, with no current treatments available to halt or reverse disease progression. This lack of effective therapeutic options is, at least in part, due to insufficient understanding of the mechanisms governing this dysregulated wound healing cascade. One clue pointing to potential drivers of IPF is the dramatic increase in incidence for patients aged 55 and above. Cellular senescence is a state of persistent cell cycle arrest characterized by distinct morphologic and metabolic changes as well as a robust, and often pro-inflammatory, secretory profile. Senescent cell accumulation is correlated with age and has thus been implicated in the progression of IPF. Yet, the mechanisms driving the persistent accumulation of senescent cells with fibrosis are not clear. Further, the interplay between senescent cells and the changing mechanics in the ageing and fibrotic lung has not been elucidated. Thus, the goal of this work is to study the interplay between senescent cells and the mechanics of their environment. This work leverages hyaluronic acid-based hydrogels as a cell culture platform for studying cellular mechanotransduction, and agent-based models that integrate experimental findings to recapitulate interactions between cells and their environment during fibrosis progression in the lung. We first characterize a novel approach for fabricating these hydrogels in high-throughput within a 96-well plate platform for the multi-factorial investigation of cellular phenotype. We then leverage this hydrogel fabrication approach to investigate the influence of hydrogel stiffness and viscoelasticity on YAP signaling and senescence induction in human lung fibroblasts. Finally, we describe the development of an agent-based model of fibrosis progression in the aged lung to investigate the influence of senescent cell behavior and clearance on the mechanical burden of the lung. Overall, this work provides novel tools and unique insights regarding the mechanobiology of senescent cells and their role in perpetuating pulmonary fibrosis.