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.
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.
Lefort
Nathalie
N
Inserm U 421, Faculté de Médecine, Créteil, France.
Benne
Clarisse
C
Lelièvre
Jean Daniel
JD
Dorival
Céline
C
Balbo
Michèle
M
Sakano
Seiji
S
Coulombel
Laure
L
Lévy
Yves
Y
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
D048868:Adaptor Proteins, Signal Transducing; D018952:Antigens, CD34; D002135:Calcium-Binding Proteins; C424126:DLL4 protein, human; D036341:Intercellular Signaling Peptides and Proteins