Methods for Investigating Corneal Cell Interactions and Extracellular Vesicles In Vitro

Science and medicine have become increasingly “human‐centric” over the years. A growing shift away from the use of animals in basic research has led to the development of sophisticated in vitro models of various tissues utilizing human‐derived cells to study physiology and disease. The human cornea has likewise been modeled in vitro using primary cells derived from corneas obtained from cadavers or post‐transplantation. By utilizing a cell's intrinsic ability to maintain its tissue phenotype in a pre‐designed microenvironment containing the required growth factors, physiological temperature, and humidity, tissue‐engineered corneas can be grown and maintained in culture for relatively long periods of time on the scale of weeks to months. Due to its transparency and avascularity, the cornea is an optimal tissue for studies of extracellular matrix and cell‐cell interactions, toxicology and permeability of drugs, and underlying mechanisms of scarring and tissue regeneration. This paper describes methods for the cultivation of corneal keratocytes, fibroblasts, epithelial, and endothelial cells for in vitro applications. We also provide detailed, step‐by‐step protocols for assembling and culturing 3D constructs of the corneal stroma, epithelial‐ and endothelial‐stromal co‐cultures and isolation of extracellular vesicles. © 2020 Wiley Periodicals LLC. Basic Protocol 1 : Isolating and culturing human corneal keratocytes and fibroblasts Basic Protocol 2 : Isolating and culturing human corneal epithelial cells Basic Protocol 3 : Isolating and culturing human corneal endothelial cells Basic Protocol 4 : 3D corneal stromal construct assembly Basic Protocol 5 : 3D corneal epithelial‐stromal construct assembly Basic Protocol 6 : 3D corneal endothelial‐stromal construct assembly Basic Protocol 7 : Isolating extracellular vesicles from corneal cell conditioned medium Support Protocol : Cryopreserving human corneal fibroblasts, corneal epithelial cells, and corneal endothelial cells