Soluble factors elaborated by human brain endothelial cells induce the concomitant expansion of purified human BM CD34+CD38- cells and SCID-repopulating cells.

摘要: The CD34+CD38– phenotype identifies a population in the bone marrow that is enriched steady state for hematopoietic stem cells (HSCs). Following ex vivo culture of CD34+ cells, HSC content difficult to measure since committed CD34+CD38+ progenitors down-regulate CD38 surface expression during culture. In this study, we sought define human HSCs following under conditions support expansion capable repopulating non-obese diabetic/severe combined immunodeficiency (SCID)–repopulating (SRCs). Contact coculture fluorescence-activated cell sorter (FACS)–sorted (BM) with brain endothelial (HUBECs) supported 4.4-fold increase concordant 3.6-fold SRCs over 7 days. Noncontact HUBEC cultures and addition thrombopoietin, factor (SCF), macrophage colony stimulating I receptor (Fms)–like tyrosine kinase 3 (Flt-3) ligand further increases (6.4-fold 13.1-fold), which correlated significant SRC activity. Moreover, cell-sorting studies performed on HUBEC-cultured populations demonstrated were significantly within subset compared CD34–CD38– after These results indicate can be identified characterized by also demonstrate HUBEC-elaborated soluble factors mediate unique potent HSCs.