In transgenic mice expressing diphtheria toxin receptor under the control of the mouse surfactant protein C promoter (a model of pulmonary fibrosis targeting type IIalveolar epithelial injury), PDE4 inhibitor also downregulated plasma levels of selective chemokines, and significantly reduces lung fibrosis induced by targeted type II AEC injury (Sisson et al., 2018). This evidence concerns the gene HBEGF and pulmonary fibrosis.