title: KL-6 regulated the expression of HGF, collagen and myofibroblast differentiation.
abstract: OBJECTIVE
  KL-6 is a pulmonary epithelial-derived mucin which is secreted mainly by type II alveolar epithelial cells. The level of KL-6 in serum is closely correlated to the clinical activity of various interstitial lung diseases (ILD) and acts as a prognostic factor for ILD patients. Previous studies have showed that KL-6 promoted chemotaxis, proliferation and inhibited the apoptosis of human lung fibroblasts. However, the underlying mechanism remains unknown. In this study, we investigated the function of KL-6 on the expression of hepatocyte growth factor (HGF), transforming growth factor-β1 (TGF-β1), collagen and α-smooth muscle actin(α-SMA) in human embryonic lung fibroblasts cell line MRC-5.
  
  
  METHODS
  Human embryonic lung fibroblasts were cultured in Eagle's minimum essential medium. The cells plated in 6-well plates was cultured in serum-free medium at 37°C in 5% CO2 and challenged with recombinant KL-6 at a final concentration of 0, 10, 20, 40 ng/mL. Five micrograms of total RNA template were transcripted to cDNA by using AMV (Avian Myeloblastosis Virus) reverse transcriptase and random 9 mers as the first-strand primer. Synthesized cDNA was used in PCR experiments. The expression of TGF-β1 and HGF in cell culture supernatants was measured using ELISA kit. Cells incubated with KL-6 for 72h were collected for flow-cytometry analysis. The analysis was done using a Beckman counter device.
  
  
  RESULTS
  It was found that KL-6 up-regulated the expression of collagen type I and III in a dose-dependent manner. However, the addition of KL-6 significantly inhibited the production of HGF. As regard to the biological function, KL-6 induced myofibroblast differentiation confirmed by the elevated expression of a-SMA.
  
  
  CONCLUSIONS
  KL-6 is one of the key molecules involved in epithelial-mesenchymal interactions and might contribute to the fibrosis in ILD.
authors.affiliation: Department of Respiratory Medicine, Shanghai Sixth People's Hospital, Shanghai Jiaotong University, Shanghai, China. lingxu201206@sina.cn.
authors.forename: L
authors.initials: L
authors.lastname: Xu
authors.forename: D-R
authors.initials: DR
authors.lastname: Yan
authors.forename: S-L
authors.initials: SL
authors.lastname: Zhu
authors.forename: J
authors.initials: J
authors.lastname: Gu
authors.forename: W
authors.initials: W
authors.lastname: Bian
authors.forename: Z-H
authors.initials: ZH
authors.lastname: Rong
authors.forename: C
authors.initials: C
authors.lastname: Shen
mesh_terms: D002454:Cell Differentiation / Q000187:drug effects; D002478:Cells, Cultured; D003094:Collagen / Q000235:genetics*; D005786:Gene Expression Regulation / Q000187:drug effects; D017228:Hepatocyte Growth Factor / Q000235:genetics*; D006801:Humans; D018396:Mucin-1 / Q000494:pharmacology*; D058628:Myofibroblasts / Q000166:cytology / Q000187:drug effects*; D011994:Recombinant Proteins / Q000494:pharmacology
chemical_list: C060192:MUC1 protein, human; D018396:Mucin-1; D011994:Recombinant Proteins; D017228:Hepatocyte Growth Factor; D003094:Collagen