RT Journal Article SR Electronic T1 Fas activation alters tight junction proteins in acute lung injury JF Thorax JO Thorax FD BMJ Publishing Group Ltd and British Thoracic Society SP 69 OP 82 DO 10.1136/thoraxjnl-2018-211535 VO 74 IS 1 A1 Herrero, Raquel A1 Prados, Lucia A1 Ferruelo, Antonio A1 Puig, Ferranda A1 Pandolfi, Rachele A1 Guillamat-Prats, Raquel A1 Moreno, Laura A1 Matute-Bello, Gustavo A1 Artigas, Antonio A1 Esteban, Andres A1 Lorente, José Ángel YR 2019 UL http://thorax.bmj.com/content/74/1/69.abstract AB Background:The acute respiratory distress syndrome (ARDS) is characterized by protein-rich oedema in the alveolar spaces, a feature in which Fas-mediated apoptosis of the alveolar epithelium has been involved. Objective:To determine whether Fas activation increases protein permeability by mechanisms involving disruption of the paracellular tight junction (TJ) proteins in the pulmonary alveoli. Methods: Protein permeability and the expression of TJ proteins were assessed in vivo in wild-type and Fas-deficient lpr mice 16 hours after the intratracheal instillation of recombinant human soluble Fas ligand (rh-sFasL), and at different time points in vitro in human pulmonary alveolar epithelial cells (HPAEpiC) exposed to rh-sFasL Results:Activation of the Fas pathway increased protein permeability in mouse lungs and altered the expression of the TJ proteins occludin and zonula occludens-1 in the alveolar–capillary membrane in vivo and in human alveolar epithelial cell monolayers in vitro. Blockade of caspase-3, but not inhibition of tyrosine kinase dependent pathways, prevented the alterations in TJ protein expression and permeability induced by the Fas/FasL system in human alveolar cell monolayers in vitro. We also observed that both the Fas-induced increase of protein permeability and disruption of TJ proteins occurred before cell death could be detected in the cell monolayers in vitro. Conclusion:Targeting caspase pathways could prevent the disruption of TJs and reduce the formation of lung oedema in the early stages of ARDS.