title: Mesenchymal lineage potentials of aorta-gonad-mesonephros stromal clones.
abstract: OBJECTIVE
  The characterization of stem cell microenvironments throughout ontogeny is of fundamental interest in the field of stem cell biology. Within the adult blood system, hematopoietic stem cells (HSC) are supported in the osteoblastic and endothelial bone marrow microenvironments. During mouse mid-gestation, the first HSC emerge autonomously in the aorta-gonad-mesonephros (AGM) region. However, little is known about this microenvironment. To study the cellular complexity of the AGM hematopoietic microenvironment and its relationship to HSC, we examined the potential of AGM stromal clones to differentiate into several mesenchymal lineages.
  
  
  METHODS
  Stromal cell clones from the mid-gestation mouse were cultured in appropriate conditions known to support osteogenic, adipogenic, chondrogenic and endothelial differentiation. Potentials of the stromal cells were scored by morphological examination of the cultures, specific staining and gene expression profile.
  
  
  RESULTS
  We show that most clones possess uni/bilineage osteogenic, adipogenic and/or endothelial potential. The differentiation potential of the stromal clones appears to relate to their site of origin but not to their ability to support hematopoiesis. Moreover, we show that AGM HSC activity is unaffected by the osteogenic differentiation of UG26.1B6 stromal cells.
  
  
  CONCLUSIONS
  These results confirm the existence of mesenchymal stem/progenitor cells in the AGM region and suggest that the AGM hematopoietic microenvironment is highly complex, containing stromal cells with various mesenchymal lineage potentials.
authors.affiliation: Department of Cell Biology and Genetics, Erasmus University Medical Center, Rotterdam, NL, the Netherlands.
authors.forename: Charles
authors.initials: C
authors.lastname: Durand
authors.forename: Catherine
authors.initials: C
authors.lastname: Robin
authors.forename: Elaine
authors.initials: E
authors.lastname: Dzierzak
mesh_terms: D000818:Animals; D001011:Aorta / Q000166:cytology; D019070:Cell Lineage; D002478:Cells, Cultured; D006066:Gonads / Q000166:cytology; D006412:Hematopoietic Stem Cells; D059630:Mesenchymal Stem Cells / Q000166:cytology*; D008650:Mesonephros / Q000166:cytology; D051379:Mice; D039902:Multipotent Stem Cells / Q000166:cytology; D017154:Stromal Cells / Q000166:cytology*