MMP14 and pulmonary fibrosis: To investigate the role of MMP14 expressed in the alveolar epithelium in experimental lung fibrosis, SftpcrtTA/tetO/Cre and Mmp14fl/fl mice were used to generate a conditional knockout (cKO) Sftpc-Mmp14-cKO mice carrying a doxycycline-inducible Cre recombinase.