title: Hypermethylation of DDAH2 promoter contributes to the dysfunction of endothelial progenitor cells in coronary artery disease patients.
abstract: BACKGROUND
  Circulating endothelial progenitor cells (EPCs) may be a biomarker for vascular function and cardiovascular risk in patients with coronary artery disease (CAD). Dimethylarginine dimethylaminohydrolase 2 (DDAH2) regulates the function of EPCs. This study aimed to examine whether hypermethylation of DDAH2 promoter contributes to impaired function of EPCs in CAD patients.
  
  
  METHODS
  Peripheral blood mono-nuclear cells from 25 CAD patients and 15 healthy volunteers were collected and differentiated into EPCs. EPCs were tested for their adhesive capability. DDAH2 mRNA expression was analyzed by real-time PCR, and the methylation of DDAH2 promoter was detected by bisulfite genomic sequencing.
  
  
  RESULTS
  DDAH2 promoter in EPCs from CAD patients was hypermethylated and the methylation level was negatively correlated to DDAH2 mRNA level and adhesion function of EPCs. Homocysteine impaired the adhesion function of EPCs, accompanied by lower DDAH2 expression and higher methylation level of DDAH2 promoter, compared to controls. These effects of homocysteine were reversed by pretreatment with Aza, an inhibitor of DNA methyltransferase.
  
  
  CONCLUSIONS
  Hypermethylation in DDAH2 promoter is positively correlated to the dysfunction of EPCs in CAD patients. Homocysteine disrupts EPCs function via inducing the hypermethylation of DDAH2 promoter, suggesting a key role of epigenetic mechanism in the progression of atherosclerosis.
authors.forename: Pan-Pan
authors.initials: PP
authors.lastname: Niu
authors.forename: Yu
authors.initials: Y
authors.lastname: Cao
authors.forename: Ting
authors.initials: T
authors.lastname: Gong
authors.forename: Jin-Hui
authors.initials: JH
authors.lastname: Guo
authors.affiliation: Department of Pharmaceutics, The Third Xiangya Hospital, Central South University, Tongzipo Road #138, Changsha 410013, China. zhbk@126.com.
authors.forename: Bi-Kui
authors.initials: BK
authors.lastname: Zhang
authors.forename: Su-Jie
authors.initials: SJ
authors.lastname: Jia
mesh_terms: D000368:Aged; D000581:Amidohydrolases / Q000235:genetics*; D001483:Base Sequence; D016022:Case-Control Studies; D002448:Cell Adhesion; D002478:Cells, Cultured; D003324:Coronary Artery Disease / Q000473:pathology*; D019175:DNA Methylation; D017931:DNA Primers; D066026:Endothelial Progenitor Cells / Q000473:pathology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011401:Promoter Regions, Genetic; D012333:RNA, Messenger / Q000235:genetics; D060888:Real-Time Polymerase Chain Reaction
chemical_list: D017931:DNA Primers; D012333:RNA, Messenger; D000581:Amidohydrolases; C059999:dimethylargininase