title: Epigenetic regulation of myofibroblast differentiation and extracellular matrix production in nasal polyp-derived fibroblasts.
abstract: BACKGROUND
  Nasal polyposis is a multi-factorial disease associated with chronic inflammatory condition of the paranasal sinuses. Myofibroblast differentiation and extracellular matrix (ECM) accumulation are involved in the pathogenesis of nasal polyposis.
  
  
  OBJECTIVE
  The aim of this study was to study the effect of trichostatin A (TSA), a histone deacetylase (HDAC) inhibitor, on transforming growth factor (TGF)-β1-induced myofibroblast differentiation and ECM accumulation in nasal polyp-derived fibroblasts (NPDFs).
  
  
  METHODS
  Nasal polyp-derived fibroblasts were isolated from nasal polyps of patients who have chronic rhinosinusitis with nasal polyp. TSA was treated in TGF-β1-induced NPDFs. Expression levels of HDAC2, α-smooth muscle actin (SMA), TGF-β1, collagen type I, acetylated Histone H3, acetylated Histone H4, phosphorylated Smad2/3 and Smad7 were determined by RT-PCR, western blot and/or immunofluorescent staining. The total collagen amount production was analysed by Sircol soluble collagen assay and contractile activity was measured by collagen gel contraction assay. HDAC2 inhibition by TSA or HDAC2 silencing was established by RT-PCR and western blot. The epigenetic effect on α-SMA gene inactivation was examined by chromatin immunoprecipitation assay. Proliferation was determined by Ki67-positive cell staining and cytotoxicity was assessed by 3-(4,5- dimethylthiazol-2yl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) assay.
  
  
  RESULTS
  The expression levels of HDAC2, α-SMA and TGF-β1 were increased in nasal polyp tissues compared to normal inferior turbinate tissues. TSA and HDAC2 silencing inhibited expression levels α-SMA, collagen and HDAC2. TSA induced hyperacetylation of histone and suppressed opening of α-SMA gene promoter in TGF-β1-induced NPDFs. TSA inhibited TGF-β1-induced Smad 2/3 and rescued TGF-β1-suppressed Smad7 signalling pathway. Finally, TSA blocked proliferation in TGF-β1-induced NPDFs and has no cytotoxic effect in NPDFs.
  
  
  CONCLUSIONS
  These results suggest that HDAC inhibition is associated with myofibroblast differentiation and extracelluar matrix accumulation in nasal polyposis. TSA may be useful as an inhibitor of nasal polyp growth, and thus has potential to be used as a novel treatment option for nasal polyposis.
authors.affiliation: Brain Korea 21 Project for Biomedical Science, College of Medicine, Korea University, Seoul, Korea.
authors.forename: J-S
authors.initials: JS
authors.lastname: Cho
authors.forename: Y-M
authors.initials: YM
authors.lastname: Moon
authors.forename: I-H
authors.initials: IH
authors.lastname: Park
authors.forename: J-Y
authors.initials: JY
authors.lastname: Um
authors.forename: J-H
authors.initials: JH
authors.lastname: Moon
authors.forename: S-J
authors.initials: SJ
authors.lastname: Park
authors.forename: S H
authors.initials: SH
authors.lastname: Lee
authors.forename: H J
authors.initials: HJ
authors.lastname: Kang
authors.forename: H-M
authors.initials: HM
authors.lastname: Lee
mesh_terms: D000107:Acetylation / Q000187:drug effects; D000199:Actins / Q000235:genetics / Q000378:metabolism; D002454:Cell Differentiation / Q000187:drug effects; D049109:Cell Proliferation / Q000187:drug effects; D002478:Cells, Cultured; D044127:Epigenesis, Genetic; D005109:Extracellular Matrix / Q000378:metabolism*; D005347:Fibroblasts / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D005786:Gene Expression Regulation / Q000187:drug effects; D056464:Histone Deacetylase 2 / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D056572:Histone Deacetylase Inhibitors / Q000494:pharmacology; D006657:Histones / Q000378:metabolism; D006801:Humans; D006877:Hydroxamic Acids / Q000494:pharmacology; D058628:Myofibroblasts / Q000166:cytology* / Q000378:metabolism*; D009298:Nasal Polyps / Q000235:genetics* / Q000378:metabolism*; D010766:Phosphorylation / Q000187:drug effects; D051899:Smad2 Protein / Q000378:metabolism; D051900:Smad3 Protein / Q000378:metabolism; D053773:Transforming Growth Factor beta1 / Q000235:genetics / Q000378:metabolism
chemical_list: C541116:ACTA2 protein, human; D000199:Actins; D056572:Histone Deacetylase Inhibitors; D006657:Histones; D006877:Hydroxamic Acids; D051899:Smad2 Protein; D051900:Smad3 Protein; D053773:Transforming Growth Factor beta1; C012589:trichostatin A; D056464:Histone Deacetylase 2