title: Different thresholds of Notch signaling bias human precursor cells toward B-, NK-, monocytic/dendritic-, or T-cell lineage in thymus microenvironment.
abstract: Notch receptors are involved in lineage decisions in multiple developmental scenarios, including hematopoiesis. Here, we treated hybrid human-mouse fetal thymus organ culture with the gamma-secretase inhibitor 7 (N-[N-(3,5-difluorophenyl)-l-alanyl]-S-phenyl-glycine t-butyl ester) (DAPT) to establish the role of Notch signaling in human hematopoietic lineage decisions. The effect of inhibition of Notch signaling was studied starting from cord blood CD34(+) or thymic CD34(+)CD1(-), CD34(+)CD1(+), or CD4ISP progenitors. Treatment of cord blood CD34(+) cells with low DAPT concentrations results in aberrant CD4ISP and CD4/CD8 double-positive (DP) thymocytes, which are negative for intracellular T-cell receptor beta (TCRbeta). On culture with intermediate and high DAPT concentrations, thymic CD34(+)CD1(-) cells still generate aberrant intracellular TCRbeta(-) DP cells that have undergone DJ but not VDJ recombination. Inhibition of Notch signaling shifts differentiation into non-T cells in a thymic microenvironment, depending on the starting progenitor cells: thymic CD34(+)CD1(+) cells do not generate non-T cells, thymic CD34(+)CD1(-) cells generate NK cells and monocytic/dendritic cells, and cord blood CD34(+)Lin(-) cells generate B, NK, and monocytic/dendritic cells in the presence of DAPT. Our data indicate that Notch signaling is crucial to direct human progenitor cells into the T-cell lineage, whereas it has a negative impact on B, NK, and monocytic/dendritic cell generation in a dose-dependent fashion.
authors: Department of Clinical Chemistry, Microbiology and Immunology, Ghent University, University Hospital Ghent, Belgium.
authors: Magda
authors: M
authors: De Smedt
authors: Inge
authors: I
authors: Hoebeke
authors: Katia
authors: K
authors: Reynvoet
authors: Georges
authors: G
authors: Leclercq
authors: Jean
authors: J
authors: Plum
mesh_terms: D053829:Amyloid Precursor Protein Secretases; D000818:Animals; D015703:Antigens, CD / Q000276:immunology; D016282:Aspartic Acid Endopeptidases; D004306:Dose-Response Relationship, Immunologic; D010450:Endopeptidases / Q000276:immunology; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005312:Fetal Blood / Q000166:cytology / Q000276:immunology*; D015329:Gene Rearrangement, T-Lymphocyte / Q000187:drug effects / Q000276:immunology; D006801:Humans; D007962:Leukocytes / Q000276:immunology*; D051379:Mice; D009924:Organ Culture Techniques; D016693:Receptors, Antigen, T-Cell, alpha-beta / Q000276:immunology; D051880:Receptors, Notch / Q000276:immunology*; D015398:Signal Transduction / Q000187:drug effects / Q000276:immunology*; D013234:Stem Cells / Q000166:cytology / Q000276:immunology*; D013950:Thymus Gland / Q000166:cytology / Q000276:immunology*; D014280:Triglycerides / Q000494:pharmacology; D005680:gamma-Aminobutyric Acid / Q000031:analogs & derivatives / Q000494:pharmacology
chemical_list: D015703:Antigens, CD; D004791:Enzyme Inhibitors; D016693:Receptors, Antigen, T-Cell, alpha-beta; D051880:Receptors, Notch; D014280:Triglycerides; D005680:gamma-Aminobutyric Acid; C057077:1,2-dilinolenoyl-3-(4-aminobutyryl)propane-1,2,3-triol; D053829:Amyloid Precursor Protein Secretases; D010450:Endopeptidases; D016282:Aspartic Acid Endopeptidases; C509280:BACE1 protein, human; C509282:Bace1 protein, mouse