In Vitro Generation of Hematopoietic Stem Cells from Embryonic Stem Cell to Reconstruct Hematopoiesis / 实用儿科临床杂志

ABSTRACT

Objective To search for a good method for generation of hematopoietic stem cells (HSC) by embryonic stem cells (ESC),and to investigate the potential of HSC derived from ESC to reconstruct hematopoiesis in vivo.Methods Using a three-step method to induce a mice ESC line, E14.1-into HSC.And identifying HSC by flow cytometry analysis cell markers with CD34 +/Sca-1+, then HSC (1×109L-1)from ESC differentiation were injected into severe combined immunodefieency (SCID) mice for observing teratoma formation.To validate function of HSC by colonngenic cells assay and to reconstitute the hematopoiesis in lethally irradiated mice.Results Combining to use more hematopoietic stimulating factor to availably promote the El4.1 cell into embryoid body (EBs) with abundant hematopoietic progenitors.EBs were induced after 14 day to fast differentiate for HSC with peak percentages of CD34+/Sca-1+ cells reached to (13.72±2.07)%.To harvested ceils from EBs by day 14 for second -step HSC differentiation, percent of CD34+/Sca-1+ cells rise to(24.62±2.50) % after day 16 induction.Cloning forming units (CFU) analysis showed that more Erythro -myeloid cloning generation was observed at this period.Cells obtained in the second step are subsequently plated on monolayer of mice bone marrow stromal cells, in the presence of TPO, FLt3 ligand and superoatant of mice fetal liver stromal cells, cultured for additional 15 days, followed fast expansion of CD34+/Sca-1+ to maximally (58.64±4.20 ) % with more CFU-E, CFU-GM and CFU-GEMM population.Wright-Giemsa stain showed that its had the character of hematopoietic progenitors.Cells from the third-step were injected into SCID mice, but no teratomas were recovered in 2 mices after 6 weeks.Positive selection of CD34+/Sca-1+ cells by magnetic sorting from the third - step differentiation were transplanted into 7 lethally irradiated female mice while predominant hematopoietic reconstitution were observed in 10 days after transplantation, with 71.4% successful engraftment rate.And 3 recipients showed that the cell population of the peripheral blood leukocytes,red cells, hemoglobin approached normal index at 40 days after transplant, hut followed relative'slow renew in platelet count.Survival rate of transplant group is 43.0%, compared to 100% mortality in control mice.Karyotyping assays confirmed female mice with XY.Conclusions The results showed that the three-step differentiation and the culture conditions described here good support differentiation of ESC into HSC.HSC derived from ESC were safe without teratomas formation in body, and its can reconstruct hematopoiesis.