title: DNA demethylation-dependent enhancement of toll-like receptor-2 gene expression in cystic fibrosis epithelial cells involves SP1-activated transcription.
abstract: BACKGROUND
  The clinical course of cystic fibrosis (CF) is characterized by recurrent pulmonary infections and chronic inflammation. We have recently shown that decreased methylation of the toll-like receptor-2 (TLR2) promoter leads to an apparent CF-related up-regulation of TLR2. This up-regulation could be responsible, in part, for the CF-associated enhanced proinflammatory responses to various bacterial products in epithelial cells. However, the molecular mechanisms underlying DNA hypomethylation-dependent enhancement of TLR2 expression in CF cells remain unknown.
  
  
  RESULTS
  The present study indicates that there is a specific CpG region (CpG#18-20), adjacent to the SP1 binding site that is significantly hypomethylated in several CF epithelial cell lines. These CpGs encompass a minimal promoter region required for basal TLR2 expression, and suggests that CpG#18-20 methylation regulates TLR2 expression in epithelial cells. Furthermore, reporter gene analysis indicated that the SP1 binding site is involved in the methylation-dependent regulation of the TLR2 promoter. Inhibition of SP1 with mithramycin A decreased TLR2 expression in both CF and 5-azacytidine-treated non-CF epithelial cells. Moreover, even though SP1 binding was not affected by CpG methylation, SP1-dependent transcription was abolished by CpG methylation.
  
  
  CONCLUSIONS
  This report implicates SP1 as a critical component of DNA demethylation-dependent up-regulation of TLR2 expression in CF epithelial cells.
authors.affiliation: Department of Molecular Medicine, Graduate School of Pharmaceutical Science, Global COE Cell Fate Regulation Research and Education Unit, Kumamoto University, Kumamoto 862-0973, Japan. furutakashi@molmed730.com
authors.forename: Takashi
authors.initials: T
authors.lastname: Furuta
authors.forename: Tsuyoshi
authors.initials: T
authors.lastname: Shuto
authors.forename: Shogo
authors.initials: S
authors.lastname: Shimasaki
authors.forename: Yuko
authors.initials: Y
authors.lastname: Ohira
authors.forename: Mary Ann
authors.initials: MA
authors.lastname: Suico
authors.forename: Dieter C
authors.initials: DC
authors.lastname: Gruenert
authors.forename: Hirofumi
authors.initials: H
authors.lastname: Kai
mesh_terms: D001665:Binding Sites; D002460:Cell Line; D018899:CpG Islands; D003550:Cystic Fibrosis / Q000235:genetics* / Q000473:pathology*; D019175:DNA Methylation; D004847:Epithelial Cells; D005786:Gene Expression Regulation; D006801:Humans; D008954:Models, Biological; D011401:Promoter Regions, Genetic / Q000235:genetics; D011485:Protein Binding; D016329:Sp1 Transcription Factor / Q000378:metabolism*; D051195:Toll-Like Receptor 2 / Q000235:genetics*; D014158:Transcription, Genetic
chemical_list: D016329:Sp1 Transcription Factor; D051195:Toll-Like Receptor 2