title: Molecular definition of an in vitro niche for dendritic cell development.
abstract: OBJECTIVE
  Although dendritic cell (DC) precursors have been isolated from many lymphoid sites, the regulation and location of early DC development is still poorly understood. Here we describe a splenic microenvironment that supports DC hematopoiesis in vitro and identify gene expression specific for that niche.
  
  
  METHODS
  The DC supportive function of the STX3 splenic stroma and the lymph node-derived 2RL22 stroma for overlaid bone marrow cells was assessed by coculture over 2 weeks. The DC supportive function of SXT3 was identified in terms of specific gene expression in STX3 and not 2RL22 using Affymetrix microchips.
  
  
  RESULTS
  STX3 supports DC differentiation from overlaid bone marrow precursors while 2RL22 does not. A dataset of 154 genes specifically expressed in STX3 and not 2RL22 was retrieved from Affymetrix results. Functional annotation has led to selection of 26 genes as candidate regulators of the microenvironment supporting DC hematopoiesis. Specific expression of 14 of these genes in STX3 and not 2RL22 was confirmed by reverse transcription-polymerase chain reaction.
  
  
  CONCLUSIONS
  Some genes specifically expressed in STX3 have been previously associated with hematopoietic stem cell niches. A high proportion of genes encode growth factors distinct from those commonly used for in vitro development of DC from precursors. Potential regulators of a DC microenvironment include genes involved in angiogenesis, hematopoiesis, and development, not previously linked to DC hematopoiesis.
authors.affiliation: School of Biochemistry and Molecular Biology, Australian National University, Canberra, Australia.
authors.forename: Geneviève
authors.initials: G
authors.lastname: Despars
authors.forename: Keping
authors.initials: K
authors.lastname: Ni
authors.forename: Antoine
authors.initials: A
authors.lastname: Bouchard
authors.forename: Terence J
authors.initials: TJ
authors.lastname: O'Neill
authors.forename: Helen C
authors.initials: HC
authors.lastname: O'Neill
mesh_terms: D000818:Animals; D001854:Bone Marrow Cells / Q000166:cytology / Q000502:physiology*; D002454:Cell Differentiation / Q000235:genetics / Q000502:physiology*; D002478:Cells, Cultured; D018920:Coculture Techniques; D003713:Dendritic Cells / Q000502:physiology*; D020869:Gene Expression Profiling; D005786:Gene Expression Regulation / Q000235:genetics / Q000502:physiology*; D006410:Hematopoiesis / Q000235:genetics / Q000502:physiology; D008198:Lymph Nodes / Q000166:cytology* / Q000502:physiology; D051379:Mice; D018919:Neovascularization, Physiologic / Q000235:genetics / Q000502:physiology; D020411:Oligonucleotide Array Sequence Analysis; D013154:Spleen / Q000166:cytology* / Q000502:physiology; D017154:Stromal Cells / Q000166:cytology / Q000502:physiology