title: New insights to vascular smooth muscle cell and pericyte differentiation of mouse embryonic stem cells in vitro.
abstract: OBJECTIVE
  The molecular mechanisms that regulate pericyte differentiation are not well understood, partly because of the lack of well-characterized in vitro systems that model this process. In this article, we develop a mouse embryonic stem (ES) cell-based angiogenesis/vasculogenesis assay and characterize the system for vascular smooth muscle cell (VSMC) and pericyte differentiation.
  
  
  RESULTS
  ES cells that were cultured for 5 days on OP9 stroma cells upregulated their transcription of VSMC and pericyte selective genes. Other SMC marker genes were induced at a later time point, which suggests that vascular SMC/pericyte genes are regulated by a separate mechanism. Moreover, sequence analysis failed to identify any conserved CArG elements in the vascular SMC and pericyte gene promoters, which indicates that serum response factor is not involved in their regulation. Gleevec, a tyrosine kinase inhibitor that blocks platelet-derived growth factor (PDGF) spell-receptor signaling, and a neutralizing antibody against transforming growth factor (TGF) beta1, beta2, and beta3 failed to inhibit the induction of vascular SMC/pericyte genes. Finally, ES-derived vascular sprouts recruited cocultured MEF cells to pericyte-typical locations. The recruited cells activated expression of a VSMC- and pericyte-specific reporter gene.
  
  
  CONCLUSIONS
  We conclude that OP9 stroma cells induce pericyte differentiation of cocultured mouse ES cells. The induction of pericyte marker genes is temporally separated from the induction of SMC genes and does not require platelet-derived growth factor B or TGFbeta1 signaling.
authors.affiliation: Institute of Biomedicine, Department of Medical Biochemistry and Cell Biology, Sahlgrenska Academy, Göteborg University, Göteborg, Sweden.
authors.forename: Henrik
authors.initials: H
authors.lastname: Lindskog
authors.forename: Elisabet
authors.initials: E
authors.lastname: Athley
authors.forename: Erik
authors.initials: E
authors.lastname: Larsson
authors.forename: Samuel
authors.initials: S
authors.lastname: Lundin
authors.forename: Mats
authors.initials: M
authors.lastname: Hellström
authors.forename: Per
authors.initials: P
authors.lastname: Lindahl
mesh_terms: D000818:Animals; D002454:Cell Differentiation; D002478:Cells, Cultured; D018920:Coculture Techniques; D004622:Embryo, Mammalian / Q000166:cytology*; D005819:Genetic Markers; D051379:Mice; D009131:Muscle, Smooth, Vascular / Q000166:cytology*; D032389:Myocytes, Smooth Muscle / Q000166:cytology*; D020286:Pericytes / Q000166:cytology*; D020574:Proto-Oncogene Proteins c-sis / Q000502:physiology; D015203:Reproducibility of Results; D013234:Stem Cells / Q000166:cytology* / Q000378:metabolism; D017154:Stromal Cells / Q000502:physiology; D014158:Transcription, Genetic / Q000502:physiology; D016212:Transforming Growth Factor beta / Q000502:physiology; D053773:Transforming Growth Factor beta1
chemical_list: D005819:Genetic Markers; D020574:Proto-Oncogene Proteins c-sis; C508961:Tgfb1 protein, mouse; D016212:Transforming Growth Factor beta; D053773:Transforming Growth Factor beta1