Inhibiting PDE4, an enzyme responsible for degrading cAMP, shows promise in mitigating lung fibrosis by targeting epithelial alveolar type II and lung fibroblast cells (Cortijo et al. 2009; Milara et al. 2014a, b, 2015; Hatzelmann et al. 2010). Here, PDE4A is linked to pulmonary fibrosis.