Secreted factors of <i>Aspergillus fumigatus</i> cause lung epithelial barrier disruption: A study using an air–liquid interface cell culture model

The effects of Aspergillus fumigatus-conditioned medium (AFCM) on the integrity of the Calu-3 cell lung epithelial barrier were investigated. AFCM led to a decrease in transepithelial electrical resistance and the disruption of the occludin network in the epithelial barrier. Preincubation with protease inhibitors reduced the effect of AFCM by ~ 90%, demonstrating the role of fungal proteases in epithelial barrier disruption. By mass spectrometry, we identified 494 unique proteins in AFCM, including 14 peptidases of different families. Together, these findings suggest that proteases secreted by A. fumigatus were able to modulate host epithelial barrier disruption in this fungal infection process.