title: Developmental patterns and characteristics of epicardial cell markers Tbx18 and Wt1 in murine embryonic heart.
abstract: BACKGROUND
  Although recent studies have highlighted the role of epicardial cells during cardiac development and regeneration, their cardiomyogenic potential is still controversial due to the question of lineage tracing of epicardial cells. The present study therefore aimed to examine the the expression of Tbx18 and Wt1 in embryonic heart and to identify whether Tbx18 and Wt1 themselves expressed in the cardiomyocyte.
  
  
  METHODS
  Mouse embryonic hearts were collected at different stages for immunofluorescence costaining with either Tbx18 and the cardiac transcription factor Nkx2.5 or Wilms tumor 1 (Wt1) and Nkx2.5.
  
  
  RESULTS
  Tbx18 and Wt1, but not Nkx2.5, were expressed in the proepicardium and epicardium. Tbx18 was expressed in cells within the heart from E10.5 to at least E14.5; these Tbx18-expressing cells were Nkx2.5 positive, except for a few cells that were Nkx2.5 negative at E14.5. Wt1 was expressed in cells within the heart from E12.5 to at least E14.5, but these Wt1-expressing cells were Nkx2.5 negative.
  
  
  CONCLUSIONS
  The data obtained in this study demonstrate that Tbx18 is expressed in the cardiomyocytes from E10.5 to at least E14.5, and Wt1 is expressed within the heart from E12.5 to at least E14.5, but not in the cardiomyocyte. These findings may provide new insights on the role of the epicardial cells in cardiac regeneration.
authors.affiliation: Department of Cardiology, Renmin Hospital of Wuhan University, Wuhan, Hubei, PR China. zengbinwhu@yahoo.com
authors.forename: Bin
authors.initials: B
authors.lastname: Zeng
authors.forename: Xiao-feng
authors.initials: XF
authors.lastname: Ren
authors.forename: Feng
authors.initials: F
authors.lastname: Cao
authors.forename: Xiao-yang
authors.initials: XY
authors.lastname: Zhou
authors.forename: Jing
authors.initials: J
authors.lastname: Zhang
mesh_terms: D000367:Age Factors; D000818:Animals; D005455:Fluorescent Antibody Technique; D006321:Heart / Q000196:embryology*; D000072576:Homeobox Protein Nkx-2.5; D018398:Homeodomain Proteins / Q000378:metabolism; D051379:Mice; D032383:Myocytes, Cardiac / Q000378:metabolism*; D010496:Pericardium / Q000196:embryology / Q000378:metabolism*; D020825:T-Box Domain Proteins / Q000378:metabolism*; D014157:Transcription Factors / Q000378:metabolism; D025721:WT1 Proteins / Q000378:metabolism*
chemical_list: D000072576:Homeobox Protein Nkx-2.5; D018398:Homeodomain Proteins; C484469:Nkx2-5 protein, mouse; D020825:T-Box Domain Proteins; C420983:Tbx18 protein, mouse; D014157:Transcription Factors; D025721:WT1 Proteins