title: Integrin-linked kinase mediates CTGF-induced epithelial to mesenchymal transition in alveolar type II epithelial cells.
abstract: BACKGROUND
  Overexpression of connective tissue growth factor (CTGF) in alveolar type II epithelial (AT II) cells disrupts alveolar structure, causes interstitial fibrosis, and upregulates integrin-linked kinase (ILK). Whether CTGF-ILK signaling induces epithelial to mesenchymal transition (EMT) in AT II cells is unknown.
  
  
  METHODS
  Transgenic mice with targeted overexpression of CTGF in AT II cells were generated utilizing the surfactant protein C (SP-C) gene promoter and doxycycline-inducible system. AT II cells were isolated from 4-wk-old CTGF-overexpressing (CTGF+) mice and control littermates, and cultured on Matrigel. Cells were transfected with ILK siRNA, and cell morphology and expression of cell differentiation markers were analyzed.
  
  
  RESULTS
  The AT II cells from the control lungs grew in clusters and formed alveolar-like cysts and expressed SP-C. In contrast, the cells from CTGF+ lungs were spread and failed to form alveolar-like cysts. These cells expressed higher levels of CTGF, α smooth muscle actin (α-SMA), fibronectin and vimentin, the mesenchymal markers, suggesting EMT-like changes. Transfection with ILK siRNA not only dramatically attenuated ILK expression, but also decreased α-SMA expression as well as reversed cell morphological changes in CTGF+ AT II cells.
  
  
  CONCLUSIONS
  Overexpression of CTGF induces EMT in mouse primary AT II cells and this is mediated by ILK.
authors.affiliation: Division of Pediatric Pulmonology, Department of Pediatrics, University of Miami, School of Medicine, Miami, Florida.
authors.forename: Mitra
authors.initials: M
authors.lastname: Shafieian
authors.affiliation: Division of Neonatology, Department of Pediatrics, University of Miami, School of Medicine, Miami, Florida.
authors.forename: Shaoyi
authors.initials: S
authors.lastname: Chen
authors.affiliation: Division of Neonatology, Department of Pediatrics, University of Miami, School of Medicine, Miami, Florida.
authors.forename: Shu
authors.initials: S
authors.lastname: Wu
mesh_terms: D000818:Animals; D002454:Cell Differentiation; D002478:Cells, Cultured; D055513:Connective Tissue Growth Factor / Q000378:metabolism*; D004318:Doxycycline / Q000737:chemistry; D004847:Epithelial Cells / Q000166:cytology / Q000378:metabolism*; D058750:Epithelial-Mesenchymal Transition; D005355:Fibrosis / Q000503:physiopathology; D005786:Gene Expression Regulation; D051379:Mice; D008822:Mice, Transgenic; D008856:Microscopy, Fluorescence; D010641:Phenotype; D011401:Promoter Regions, Genetic; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism*; D011650:Pulmonary Alveoli / Q000166:cytology*; D037721:Pulmonary Surfactant-Associated Protein C / Q000378:metabolism; D034741:RNA, Small Interfering / Q000378:metabolism; D015398:Signal Transduction; D015854:Up-Regulation; D000099200:Scaffold Protein ILK
chemical_list: D055513:Connective Tissue Growth Factor; D004318:Doxycycline; D017346:Protein Serine-Threonine Kinases; D037721:Pulmonary Surfactant-Associated Protein C; D034741:RNA, Small Interfering; D000099200:Scaffold Protein ILK; C526318:CCN2 protein, mouse