title: Induction of MesP1 by Brachyury(T) generates the common multipotent cardiovascular stem cell.
abstract: OBJECTIVE
  Our recent work demonstrated that common cardiovascular progenitor cells are characterized and induced by the expression of the transcription factor mesoderm posterior1 (MesP1) in vertebrate embryos and murine embryonic stem cells. As the proliferative potential of stem cell-derived cardiomyocytes is limited, it is crucial to understand how MesP1 expression is mediated in order to achieve reasonable and reliable yields for novel stem cell-based therapeutic options. As potential upstream regulators of MesP1, we therefore analysed Eomes and Brachyury(T), which had been controversially discussed as being crucial for cardiovasculogenic lineage formation.
  
  
  RESULTS
  Wild-type and transgenic murine embryonic stem cell lines, mRNA analyses, embryoid body formation, and cell sorting revealed that the MesP1 positive population emerges from the Brachyury(T) positive fraction. In situ hybridizations using wild-type mouse embryos confirmed that Brachyury(T) colocalises with MesP1 in vivo. Likewise, shRNA-based loss of Brachyury(T) causes a dramatic decrease in MesP1 expression accompanied by reduced cardiac markers in differentiating embryonic stem cells, which is reflected in vivo via in situ hybridizations using Brachyury(T) knock-out embryos where MesP1 mRNA is greatly abolished. We finally defined a 3.4 kb proximal MesP1-promoter fragment which is directly bound and activated by Brachyury(T) via a T responsive element as shown via bandshift, chromatin immuneprecipitation, and reporter assays.
  
  
  CONCLUSIONS
  Our work contributes to the understanding of the earliest cardiovasculogenic events and may become an important prerequisite for cell therapy, tissue engineering, and pharmacological testing in the culture dish using pluripotent stem cell-derived as well as directly reprogrammed cardiovascular cell types.
authors.affiliation: Medizinische Klinik und Poliklinik I, Klinikum Großhadern der LMU, Marchioninistr. 15, D-81377 München, Germany. robert.david@med.uni-muenchen.de
authors.forename: Robert
authors.initials: R
authors.lastname: David
authors.forename: Veronica Barbara
authors.initials: VB
authors.lastname: Jarsch
authors.forename: Florian
authors.initials: F
authors.lastname: Schwarz
authors.forename: Petra
authors.initials: P
authors.lastname: Nathan
authors.forename: Moritz
authors.initials: M
authors.lastname: Gegg
authors.forename: Heiko
authors.initials: H
authors.lastname: Lickert
authors.forename: Wolfgang-Michael
authors.initials: WM
authors.lastname: Franz
mesh_terms: D000818:Animals; D051792:Basic Helix-Loop-Helix Proteins / Q000096:biosynthesis* / Q000235:genetics; D002319:Cardiovascular System / Q000166:cytology*; D002478:Cells, Cultured; D053595:Embryonic Stem Cells / Q000166:cytology; D005326:Fetal Proteins / Q000502:physiology*; D006801:Humans; D051379:Mice; D039902:Multipotent Stem Cells / Q000502:physiology*; D032383:Myocytes, Cardiac / Q000166:cytology*; D020825:T-Box Domain Proteins / Q000502:physiology*; D000098908:Brachyury Protein
chemical_list: D051792:Basic Helix-Loop-Helix Proteins; D005326:Fetal Proteins; D020825:T-Box Domain Proteins; D000098908:Brachyury Protein; C101538:Mesp1 protein, mouse