Expression data from cultured c-Kit+Sca-1+Lin- (KSL)cells

The Notch signaling pathway plays a critical role in regulating the proliferation and differentiation of stem and progenitor cells including hematopoietic stem and progenitor cells (HSPCs). Notch receptors and ligands are expressed in BM stromal and hematopoietic cells. A large body of evidence has demonstrated that activating Notch signaling enhances HSCs self-renewal and facilitates its expansion ex vivo. We report that an endothelium-targeted soluble Notch ligand, the DSL domain of mouse Delta-like 1 fused with a RGD motif (mD1R), efficiently promotes the expansion ex vivo of mouse bone marrow HSPCs in a Notch signaling and endocytosis dependent manner. HSPCs expanded in the presence of mD1R kept long-term HSPC repopulation capacity. We used microarrays to compare the gene expression profiles of HSPCs expanded in the presence of PBS and mD1R. KSL cells were plated on Human umbilical vein endothelial cells (HUVECs) and cultured in a serum-free medium supplemented with a cocktail containing 5 types of mouse cytokines (m5GF) in the presence of PBS or mD1R for 7 days. Then KSL cells were sorted from these cultured hematopoietic cells for RNA extraction and hybridization on Affymetrix microarrays. The experiments were repeated 3 times.