In view of the possible crosstalks between hematopoiesis and neuropoiesis, we evaluated two microenvironments, murine neonatal neural cell line C17.2 and primary embryonic aortagonad-mesonephros (AGM) stromal cells, on the ex vivo expansion of CD34 þ cells from human cord blood. In a contact culture system, C17.2 or AGM cells significantly enhanced the expansion of CD34 þ cells to a panel of early and committed hematopoietic progenitor cells. In a noncontact transwell system, pre-established C17.2 cells significantly increased the expansion of total nucleated cells, CD34 þ cells and multilineage colony forming cells (Po0.01). Expanded cells were infused into nonobese diabetic/severe-combined immunodeficient mice. The engraftment of human (hu)CD45 þ cells in the bone marrow of these mice was consistently higher in all the 10 experiments conducted with the support of C17.2 cells when compared with those in respective control groups (11.9 vs 2.43%, P ¼ 0.03). Using RT-PCR and Southern blot analysis, we showed that AGM and C17.2 cells expressed a panel of hematopoietic, bone morphogenetic and neurotrophic factors. Our data provided the first evidence on the promoting effects of a neural progenitor cell line on hematopoiesis at a noncontact condition. The mechanism could be mediated by the expression of multilineage regulatory factors.

Summary:Our prior study demonstrated that neonatal blood (NB) contained hematopoietic stem and progenitor cells that declined rapidly after birth. To validate that NB is a source of functional stem cells, we characterized this population in terms of cobblestone area-forming cells (