Cell lines Calu-3, A549, PC9, primary lung epithelial cells and immune cell supplemented sandwich cultures for lung permeation models
Air-liquid interface using Transwell technology
Human airway epithelial cells (Calu-3: bronchial, A549 and PC9: alveolar adenocarcinoma cell lines) provide the most common way to measure the compound's ability to permeate respiratory epithelial surfaces. Cell based permeation studies involve a transwell cell culture setup, in which the cells are grown on a permeable filter membrane inserts (Figure 1). Dense cell layers polarize on this filter layer to apical and basolateral sides.
Fully formed tight junctions
The cell lines form tight monolayers, expressing the tight junction associated protein; ZO-1, beta-catenin and the adherent protein E-cadherin. Optimal barrier integrity is expressed by transepithelial electrical resistance (TEER).
Mature bronchial and alveolar tissues
Anatomical differences in bronchi (Figure 2) and alveoli (Figure 3), make it necessary for complex tissue culture to be formed using the appropriate cell types. For example in alveoli the epithelial cell layer is in close contact with endothelial cells. Hence our models reflect this structure.