title: Short exposure to Notch ligand Delta-4 is sufficient to induce T-cell differentiation program and to increase the T cell potential of primary human CD34+ cells.
abstract: OBJECTIVE
  The Notch pathway plays a key role in cell fate choices and in T-cell development. The goal of our study was to evaluate whether a short in vitro stimulation of the Notch pathway may alter human progenitor cell behavior.
  
  
  METHODS
  CD34+ cord blood progenitors were exposed for 4 days to either immobilized Notch ligand Delta-4 or in control conditions. Phenotypic and molecular changes induced by the short stimulation were assessed at day 4. Next, long-term alteration of the fate of these progenitors was assessed in culture conditions suitable for B (coculture with MS5 stromal cells) and T (FTOC and OP9 stromal cells expressing Delta-4 systems) cell differentiation.
  
  
  RESULTS
  Notch activation was sufficient to trigger immunophenotypic and molecular changes consistent with early T-cell lineage differentiation. Delta-4 induced, in 4 days, CD7+cytCD3epsilon+ cells. This paralleled at the gene-transcription level with de novo expression of several T cell-related transcription factors and TCRgamma rearrangement, while B cell transcripts were simultaneous silenced. As compared to non-Delta-4 primed cells, these early changes translated to long-term alteration of the potential of cells. Delta-4 priming led to an acceleration of T-cell development, including a completion of the TCR rearrangement, when cells were cultured in systems suitable for T-cell development while B-cell development was inhibited.
  
  
  CONCLUSIONS
  A transient Notch activation is sufficient to promote T-cell differentiation from cord blood CD34+ cells. This system may be a useful tool for the amplification and the quantification of the T potential of CD34+ cells in various disease conditions.
authors.affiliation: Inserm U 421, Faculté de Médecine, Créteil, France.
authors.forename: Nathalie
authors.initials: N
authors.lastname: Lefort
authors.forename: Clarisse
authors.initials: C
authors.lastname: Benne
authors.forename: Jean Daniel
authors.initials: JD
authors.lastname: Lelièvre
authors.forename: Céline
authors.initials: C
authors.lastname: Dorival
authors.forename: Michèle
authors.initials: M
authors.lastname: Balbo
authors.forename: Seiji
authors.initials: S
authors.lastname: Sakano
authors.forename: Laure
authors.initials: L
authors.lastname: Coulombel
authors.forename: Yves
authors.initials: Y
authors.lastname: Lévy
mesh_terms: D048868:Adaptor Proteins, Signal Transducing; D018952:Antigens, CD34 / Q000096:biosynthesis*; D001402:B-Lymphocytes / Q000187:drug effects / Q000276:immunology; D002135:Calcium-Binding Proteins; D002454:Cell Differentiation / Q000187:drug effects* / Q000276:immunology; D002478:Cells, Cultured; D006412:Hematopoietic Stem Cells / Q000187:drug effects* / Q000276:immunology; D006801:Humans; D036341:Intercellular Signaling Peptides and Proteins / Q000494:pharmacology*; D015398:Signal Transduction / Q000187:drug effects; D013601:T-Lymphocytes / Q000187:drug effects* / Q000276:immunology
chemical_list: D048868:Adaptor Proteins, Signal Transducing; D018952:Antigens, CD34; D002135:Calcium-Binding Proteins; C424126:DLL4 protein, human; D036341:Intercellular Signaling Peptides and Proteins