The effect of ATRA on liquid suspension cultures of short- and long-term repopulating hematopoietic stem cells.
2000 FACS-enriched hematopoietic precursors (lin− c-kit+ Sca-1+) were added to wells containing media and cytokines (SCF, IL-6, IL-11, and Flt-3-ligand), and cultured without (▪) or with (•) 1 μmol ATRA. Irradiated Ly5.1 recipients (10 mice per group) were transplanted with 1 × 105 normal Ly5.1 bone marrow cells together with 1000 noncultured (▴) Ly5.2 lin− c-kit+ Sca-1+ cells or with all cells that grew from 1000 of these precursors after 7 or 14 days in liquid suspension culture. Data are expressed as the mean ± SEM donor cell reconstitution in the peripheral blood of transplanted recipients analyzed between 5 weeks (1.25 mo) and 12 months after transplant. Results of noncultured cells (A, D), 7-day cultured cells (B, E) and 14-day cultured cells (C, F) are shown from 2 separate experiments (Exp. 1 and 2).
