title: Downregulated protein expression of transcriptional activator ELK-1 in atrial myocardium of chronic AF patients.
abstract: BACKGROUND
  The structural alterations in atrial myocytes appear to be an adaptive response of dedifferentiation during chronic atrial fibrillation (AF). Transcriptional activator ELK-1, one of the members of ETS family, has been shown to play an important role in regulating cell differentiation, It is reasonable to presume that ELK-1 participate in the molecular and structural remodeling by which AF is sustained. To prove this hypothesis, the expression of ELK-1 protein in chronically fibrillating atria compared to that in normal rhythmic atria was detected.
  
  
  METHODS
  Right atrial myocardium were obtained from twenty-four patients undergoing valve replacement surgery, twelve patients were in chronic AF (>6 months), whereas the others were in sinus rhythm (SR). The protein expression level of ELK-1 was quantified by Western blot analysis, and the cellular localization and expression pattern of ELK-1 was examined by immunohistochemical staining and indirect immunofluorescence.
  
  
  RESULTS
  Western blot analysis showed that the protein expression of ELK-1 was significantly reduced in the atrial tissue of chronic AF patients compared to that in the controls. Immunohistochemistry showed that ELK-1 immunostaining occurred in both cytosolic and nuclear compartments of atrial myocardium. Indirect immunofluorescence showed that the nuclei of normal rhythmic atrial cells were densely labeled, whereas the nuclei in chronically fibrillating atrial cells were very faintly labeled.
  
  
  CONCLUSIONS
  Our results suggest that the downregulated expression of transcriptional activator ELK-1 may play an important role in the pathogenesis of AF.
authors.affiliation: Department of Cardiovascular Surgery, Guangdong Provincial Cardiovascular Institute, Guangdong General Hospital/Guangdong Academy of Medical Sciences 106 Zhong Shan Er Lu, Guangzhou 510080, Guangdong Province, China.
authors.forename: Xiangjun
authors.initials: X
authors.lastname: Zeng
authors.affiliation: Department of Cardiovascular Surgery, Guangdong Provincial Cardiovascular Institute, Guangdong General Hospital/Guangdong Academy of Medical Sciences 106 Zhong Shan Er Lu, Guangzhou 510080, Guangdong Province, China.
authors.forename: Xuejun
authors.initials: X
authors.lastname: Xiao
authors.affiliation: Department of Cardiovascular Surgery, Guangdong Provincial Cardiovascular Institute, Guangdong General Hospital/Guangdong Academy of Medical Sciences 106 Zhong Shan Er Lu, Guangzhou 510080, Guangdong Province, China.
authors.forename: Yueheng
authors.initials: Y
authors.lastname: Wu
authors.affiliation: Department of Cardiovascular Surgery, Guangdong Provincial Cardiovascular Institute, Guangdong General Hospital/Guangdong Academy of Medical Sciences 106 Zhong Shan Er Lu, Guangzhou 510080, Guangdong Province, China.
authors.forename: Huanlei
authors.initials: H
authors.lastname: Huang
mesh_terms: D000328:Adult; D001281:Atrial Fibrillation / Q000175:diagnosis / Q000378:metabolism* / Q000601:surgery; D015153:Blotting, Western; D016022:Case-Control Studies; D002908:Chronic Disease; D015536:Down-Regulation; D005260:Female; D019084:Fluorescent Antibody Technique, Indirect; D006325:Heart Atria / Q000737:chemistry* / Q000601:surgery; D006801:Humans; D008297:Male; D008875:Middle Aged; D032383:Myocytes, Cardiac / Q000737:chemistry*; D050807:ets-Domain Protein Elk-1 / Q000032:analysis*
chemical_list: C494112:ELK1 protein, human; D050807:ets-Domain Protein Elk-1
keywords: Atrial fibrillation; ELK-1; dedifferentiation; transcriptional activator