NEDD4 and idiopathic pulmonary fibrosis: Further, we demonstrated that the conditional deletion of Nedd4-2 in lung epithelial cells by doxycycline induction of adult Nedd4-2fl/fl/CCSP-rtTA2S-M2/LC1 mice, hereafter referred to as conditional Nedd4-2−/− mice, causes a chronic progressive, restrictive lung disease that shares key features with IPF in patients including signature lesions such as radiological and histological honeycombing and fibroblast foci [9].