Importantly, our in vitro findings were demonstrated in vivo, in that repeated pulmonary exposure at various doses for 4 weeks reduced junctional β-catenin and claudin-5 in the arteriolar and alveolar endothelial cell-cell junctions in a dose-dependent manner (Figure 8 and Figure 9), and correlated with enhanced infiltration of leukocytes, pulmonary fibrosis and vascular remodeling (Figure 1 and Figure 2). The gene discussed is CLDN5; the disease is pulmonary fibrosis.