As the direct role of Fizz1 in the pathogenesis of lung fibrosis remains elusive and the lung epithelial cells appear to be key producers of Fizz1, we generated transgenic mice which conditionally expresses Fizz1 under the control of a doxycycline (Dox) inducible lung epithelial cell specific promoter Scgb1a1 (Clara cell secretory protein, CCSP). Here, RETNLB is linked to pulmonary fibrosis.