Stromal expression of Jagged 1 promotes colony formation by fetal hematopoietic progenitor cells.
The Notch signaling system regulates proliferation and differentiation in many tissues. Notch is a transmembrane receptor activated by ligands expressed on adjacent cells. Hematopoietic stem cells and early progenitors express Notch, making the stromal cells which form cell-cell contacts with progenitor cells candidate ligand-presenting cells in the hematopoietic microenvironment. Therefore, we examined primary stromal cell cultures for expression of Notch ligands. Using reverse transcription-polymerase chain reaction, in situ hybridization, immunohistochemistry, and Western blotting, we demonstrate expression of Jagged 1 in primary stromal cultures. To investigate if the stromal expression of Jagged 1 has functional effects on hematopoietic progenitors, we cultured CD34(+), c-kit+ hematopoietic progenitor cells derived from the aorto gonadal mesonephros region of day 11 mouse embryos on the Jagged 1(-) stromal cell line S17 and on S17 cells engineered to express Jagged 1. The presence of Jagged 1 increased the number of colonies formed in subsequent methylcellulose culture fourfold. Larger increases in colony numbers were observed under the same culture conditions with CD34(+), c-kit+ hematopoietic progenitor cells derived from d11 fetal liver. These results obtained in vitro table Jagged 1 as a candidate regulator of stem cell fate in the context of stromal microenvironments in vivo.
Section of Gene Function and Regulation & Leukaemia Research Fund Centre, Chester Beatty Laboratories, Institute of Cancer Research, London, UK.
P
P
Jones
G
G
May
L
L
Healy
J
J
Brown
G
G
Hoyne
S
S
Delassus
T
T
Enver
D000818:Animals; D018952:Antigens, CD34 / Q000032:analysis; D001011:Aorta / Q000166:cytology / Q000196:embryology; D015153:Blotting, Western; D002135:Calcium-Binding Proteins; D002478:Cells, Cultured; D004622:Embryo, Mammalian; D015870:Gene Expression; D006066:Gonads / Q000166:cytology / Q000196:embryology; D006412:Hematopoietic Stem Cells / Q000166:cytology* / Q000276:immunology; D007150:Immunohistochemistry; D017403:In Situ Hybridization; D036341:Intercellular Signaling Peptides and Proteins; D000072100:Jagged-1 Protein; D008565:Membrane Proteins / Q000235:genetics*; D008650:Mesonephros / Q000166:cytology / Q000196:embryology; D051379:Mice; D008810:Mice, Inbred C57BL; D008808:Mice, Inbred CBA; D016133:Polymerase Chain Reaction; D019009:Proto-Oncogene Proteins c-kit / Q000032:analysis; D012194:RNA-Directed DNA Polymerase; D000072099:Serrate-Jagged Proteins; D017154:Stromal Cells / Q000378:metabolism*
D018952:Antigens, CD34; D002135:Calcium-Binding Proteins; D036341:Intercellular Signaling Peptides and Proteins; C000606274:Jag1 protein, mouse; D000072100:Jagged-1 Protein; D008565:Membrane Proteins; D000072099:Serrate-Jagged Proteins; D019009:Proto-Oncogene Proteins c-kit; D012194:RNA-Directed DNA Polymerase