Downregulation of the TGF-β signals in bleomycin (BLM)-challenged Postn−/− mice, expression of signature molecules of pulmonary fibrosis and periostin, and activation of Smad3 in the lung tissues of patients with idiopathic pulmonary fibrosis (IPF). (A and B) BLM was administered intratracheally into periostin-deficient (Postn−/−) mice or their heterozygous littermates (Postn+/−) on Day 0. Lung tissue was prepared on Day 21. Expression of signature molecules of pulmonary fibrosis―SERPINE1, CTGF, IGFBP-3, and IL-11 (A)―and phosphorylated Smad3 (B) in the lung tissues of BLM-administered mice are depicted. The photographs of phosphorylated Smad3 (green) and DAPI (blue) with or without periostin (red) have been merged. Scale bars: 20 μm and 50 μm. (C) Hematoxylin and eosin (H&E) staining and immunostaining of SERPINE1, CTGF, IGFBP-3, IL-11, periostin, and phosphorylated Smad3 of the lung tissues of patients with usual interstitial pneumonia (UIP). Four patients with UIP were investigated; representative data are shown. The immunostains are high-magnitude images of the boxed region in the H&E staining. The photographs of phosphorylated Smad3 (green), DAPI (blue), and periostin (red) have been merged. Scale bars: 0.1 mm, 20 μm and 50 μm.