title: Effects of doxycycline on production of growth factors and matrix metalloproteinases in pulmonary fibrosis.
abstract: BACKGROUND
  Idiopathic pulmonary fibrosis (IPF) is characterized by progressive fibrosis and a poor prognosis. Alveolar epithelial cells (AECs) are considered to play important roles by releasing growth factors and matrix metalloproteinases (MMPs) and by being involved in epithelial mesenchymal transition in IPF. Doxycycline hydrochloride (DOXY), an inhibitor of MMPs, attenuates pulmonary fibrosis in models and in patients with IPF; however, the mechanism of this action remains obscure.
  
  
  OBJECTIVE
  The present study investigated the effect of DOXY on growth factors and MMP production in AECs.
  
  
  METHODS
  Bleomycin (BL)-induced murine pulmonary fibrosis was treated with DOXY and examined by pathological and immunohistochemical staining. The human alveolar epithelial cell line A549 was stimulated with transforming growth factor (TGF)-β1 and incubated with DOXY, and then the expression of growth factors, MMPs, and collagen type I was evaluated at the mRNA and protein levels. We also evaluated the effects of DOXY on the TGF-β1-induced Smad signaling pathway.
  
  
  RESULTS
  DOXY reduced fibrosis scores and the production of collagen type I, connective tissue growth factor (CTGF), and TGF-β1 in BL models. DOXY inhibited the mRNA expression of MMP-2, MPP-9, CTGF, and collagen type I as well as the production of MMP-2 and platelet-derived growth factor-AA protein induced in A549 cells by TGF-β1 but not by Smad2 and Smad3 phosphorylation. We did not find a similar effect of DOXY in normal lung fibroblasts.
  
  
  CONCLUSIONS
  Our results suggest that DOXY could be useful for attenuating pulmonary fibrosis through the inhibition of growth factors and MMP production in AECs.
authors.affiliation: Second Department of Internal Medicine, Nagasaki University School of Medicine, Nagasaki, Japan.
authors.forename: Hanako
authors.initials: H
authors.lastname: Fujita
authors.forename: Noriho
authors.initials: N
authors.lastname: Sakamoto
authors.forename: Yuji
authors.initials: Y
authors.lastname: Ishimatsu
authors.forename: Tomoyuki
authors.initials: T
authors.lastname: Kakugawa
authors.forename: Shintaro
authors.initials: S
authors.lastname: Hara
authors.forename: Atsuko
authors.initials: A
authors.lastname: Hara
authors.forename: Misato
authors.initials: M
authors.lastname: Amenomori
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Ishimoto
authors.forename: Towako
authors.initials: T
authors.lastname: Nagata
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Mukae
authors.forename: Shigeru
authors.initials: S
authors.lastname: Kohno
mesh_terms: D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D015153:Blotting, Western; D002460:Cell Line; D024042:Collagen Type I / Q000187:drug effects / Q000378:metabolism; D055513:Connective Tissue Growth Factor / Q000187:drug effects / Q000378:metabolism; D004318:Doxycycline / Q000494:pharmacology*; D004591:Electrophoresis, Polyacrylamide Gel; D004797:Enzyme-Linked Immunosorbent Assay; D004847:Epithelial Cells / Q000378:metabolism*; D007150:Immunohistochemistry; D036341:Intercellular Signaling Peptides and Proteins / Q000378:metabolism*; D008168:Lung / Q000473:pathology; D008297:Male; D020778:Matrix Metalloproteinase 2 / Q000187:drug effects / Q000378:metabolism; D020782:Matrix Metalloproteinases / Q000187:drug effects* / Q000378:metabolism*; D051379:Mice; D008813:Mice, Inbred ICR; D010766:Phosphorylation; D010982:Platelet-Derived Growth Factor / Q000187:drug effects / Q000378:metabolism; D011650:Pulmonary Alveoli / Q000166:cytology*; D011658:Pulmonary Fibrosis / Q000188:drug therapy* / Q000378:metabolism* / Q000473:pathology; D012333:RNA, Messenger / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015398:Signal Transduction / Q000502:physiology; D051785:Smad Proteins / Q000502:physiology; D053773:Transforming Growth Factor beta1 / Q000494:pharmacology
chemical_list: D000900:Anti-Bacterial Agents; D024042:Collagen Type I; D036341:Intercellular Signaling Peptides and Proteins; D010982:Platelet-Derived Growth Factor; D012333:RNA, Messenger; D051785:Smad Proteins; D053773:Transforming Growth Factor beta1; C075278:platelet-derived growth factor A; D055513:Connective Tissue Growth Factor; D020782:Matrix Metalloproteinases; D020778:Matrix Metalloproteinase 2; D004318:Doxycycline