title: Enhancer of polycomb1 lessens neointima formation by potentiation of myocardin-induced smooth muscle differentiation.
abstract: OBJECTIVE
  Previously, we reported that enhancer of polycomb1 (Epc1) induces skeletal muscle differentiation through the serum response factor (SRF). Considering that SRF plays a critical role in vascular smooth muscle cell (VSMC) differentiation, we expected that Epc1 also works in VSMCs. Here we examined the effect of Epc1 on neointima formation after arterial balloon injury and the underlying mechanism.
  
  
  METHODS
  Epc1 expression was examined in carotid artery injury or VSMC models. Interaction with myocardin (Myocd), a master regulator of smooth muscle differentiation, was examined by immunoprecipitation or promoter analysis with smooth muscle (SM) 22α promoter. Finally, we investigated whether local delivery of Epc1 regulated neointimal formation after injury.
  
  
  RESULTS
  Epc1 expression was down-regulated during proliferation induced by platelet-derived growth factor BB, whereas it was upregulated during differentiation in VSMCs. Forced expression of Epc1 induced VSMC differentiation. Epc1 physically interacted with Myocd to synergistically activate SM22α promoter activity. Transient transfection of Epc1 enhanced the physical interaction between Myocd and SRF, whereas that interaction was reduced when A10 cells were treated with siRNA for Epc1. Local delivery of Epc1 significantly reduced neointima formation induced by balloon injury.
  
  
  CONCLUSIONS
  Our results indicate that Epc1 induces VSMC differentiation by interacting with Myocd to induce SRF-dependent smooth muscle genes. We propose that Epc1 acts as a novel negative regulator of neointima formation after carotid injury.
authors.affiliation: Department of Pharmacology and Medical Research Center for Gene Regulation, Chonnam National University Medical School, Republic of Korea.
authors.forename: Hosouk
authors.initials: H
authors.lastname: Joung
authors.forename: Jin-Sook
authors.initials: JS
authors.lastname: Kwon
authors.forename: Ju-Ryoung
authors.initials: JR
authors.lastname: Kim
authors.forename: Sera
authors.initials: S
authors.lastname: Shin
authors.forename: Wanseok
authors.initials: W
authors.lastname: Kang
authors.forename: Youngkeun
authors.initials: Y
authors.lastname: Ahn
authors.forename: Hyun
authors.initials: H
authors.lastname: Kook
authors.forename: Hae Jin
authors.initials: HJ
authors.lastname: Kee
mesh_terms: D000800:Angioplasty, Balloon; D000818:Animals; D000077214:Becaplermin; D020212:Carotid Artery Injuries / Q000378:metabolism; D002454:Cell Differentiation / Q000187:drug effects* / Q000502:physiology; D049109:Cell Proliferation / Q000187:drug effects; D015536:Down-Regulation; D051379:Mice; D008840:Microfilament Proteins / Q000235:genetics; D009124:Muscle Proteins / Q000235:genetics; D009131:Muscle, Smooth, Vascular / Q000166:cytology; D032389:Myocytes, Smooth Muscle / Q000187:drug effects; D058426:Neointima / Q000188:drug therapy; D009687:Nuclear Proteins / Q000378:metabolism*; D011401:Promoter Regions, Genetic / Q000187:drug effects; D020574:Proto-Oncogene Proteins c-sis / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D012097:Repressor Proteins / Q000378:metabolism*; D026362:Serum Response Factor / Q000378:metabolism; D015534:Trans-Activators / Q000378:metabolism*; D015854:Up-Regulation; D000099251:Myocardin
chemical_list: D000077214:Becaplermin; D008840:Microfilament Proteins; D009124:Muscle Proteins; D009687:Nuclear Proteins; D020574:Proto-Oncogene Proteins c-sis; D012097:Repressor Proteins; D026362:Serum Response Factor; D015534:Trans-Activators; D000099251:Myocardin; C496700:Epc1 protein, mouse; C058992:Tagln protein, mouse