ABSTRACT: Platelet-derived growth factor (PDGF), a growth factor for connective tissue cells, stimulates erythropoiesis and megakaryocytopoiesis
in vitro but the effect of PDGF on granulocyte proliferation remains unknown.The effect of the recombinant human PDGF-BB isoform
on granulopoiesis was investigated in this study. The results show that PDGF significantly stimulated murine colony-forming
unit-granulocyte-monocyte (CFU-GM) proliferation in a dose-dependent manner (1 to 100 ng/mL) using murine bone marrow cells
(n = 4). Maximum stimulation was obtained with 50 ng/mL of PDGF (P < .01). The effect of PDGF on murine CFU-GM proliferation
was compared with that of interleukin (IL)-3, IL-6, granulocyte-monocyte colony-stimulating factor (GM-CSF),and acidic fibroblast
growth factor (aFGF) at their optimal doses.The stimulating activity of PDGF was higher than that of aFGF but lower than that
of IL-3, IL-6, or GM-CSF. There is no synergistic effect between PDGF and IL-3 or IL-6, but a significant enhancing effect
was observed in IL-3 plus IL-6. PDGF also stimulated the growth of CFU-GM with CFU-megakaryocyte in the presence of bone marrow
stromal cells. We also found that PDGF had similar a effect on human CFU-GM proliferation using bone marrow mononuclear cells
(MNC). However, the increase in PDGF-stimulated CFU-GM proliferation was inhibited by anti-GM-CSF, anti-IL-3, and anti-IL-6
antibodies (n = 4), suggesting that endogenously produced GM-CSF, IL-3, and IL-6 may play a role in the PDGF-induced CFU-GM
proliferation. Furthermore, PDGF (1 to 100 ng/mL) did not show any effect on CFU-GM proliferation when replacing bone marrow
MNC with immunomagnetic selection-enriched CD34+ cells from human cord blood (n = 5; purity, 91% +- 6.5%).This study indicates that PDGF may indirectly enhance CFU-GM proliferation
by inducing the bone marrow stromal cells to produce GM-CSF, IL-3, or IL-6.
International Journal of Hematology 04/2012; 73(3):327-334. · 1.27 Impact Factor
ABSTRACT: Hematopoiesis during mammalian embryonic development has been perceived as a migratory phenomenon, from the yolk sac blood island to the aorta-gonad-mesonephros (AGM) region, fetal liver (FL), and subsequently, the fetal bone marrow. In this study, we investigated the effects of primary stromal cells from fetal hematopoietic niches and their conditioned media (CM), applied singly or in sequential orders, on induction of human embryonic stem cells, H1, H9, and H14 lines, to hematopoietic cells. Our results demonstrated that stromal support of FL, AGM + FL, and AGM + FL + fetal bone marrow significantly increased the proliferation of embryoid bodies (EB) at day 18 of hematopoietic induction in the presence of thrombopoietin, stem cell factor, and Flt-3 ligand. AGM + FL also increased hematopoietic colony-forming unit (CFU) formation. CM did not enhance EB proliferation but CM of FL and AGM + FL significantly increased the density of total CFU and early erythroid (burst-forming unit) progenitors. Increased commitment to the hematopoietic lineage was demonstrated by enhanced expressions of CD45, alpha-, beta-, and gamma-globins in CFU at day 32, compared with EB at day 18. CM of FL significantly increased these globin expressions, indicating enhanced switches from embryonic to fetal and adult erythropoiesis. Over 50% and 10% of cells derived from CFU expressed CD45 and beta-globin proteins, respectively. Expressions of hematopoietic regulatory genes (Bmi-1, β-Catenin, Hox B4, GATA-1) were increased in EB or CFU cultures supported by FL or sequential CM. Our study has provided a strategy for derivation of hematopoietic cells from embryonic stem cells under the influence of primary hematopoietic niches and CM, particularly the FL.
Stem cells and development 01/2011; 20(1):31-8. · 4.15 Impact Factor
ABSTRACT: Ex vivo expansion of haematopoietic stem and progenitor cells in cytokine combinations is effective in promoting differentiation and proliferation of multilineage progenitor cells, but often results in reduction of self-renewable stem cells. This study investigated the effect of a mannose-binding lectin, NTL, purified from Narcissus tazetta var. chinensis, on prolonged maintenance and expansion of cord blood CD34+ cells. Our results showed that the presence of NTL or Flt-3 ligand (FL) significantly preserved a population of early stem/progenitor cells in a serum- and cytokine-free culture for 35 d. The effect of NTL on the ex vivo expansion of CD34+ cells in the presence of stem cell factor, thrombopoietin (TPO) and FL was also investigated. NTL-enhanced expansion of early progenitors (CD34+, CD34+CD38-, mixed colony-forming units and CFU-GEMM) and committed progenitor cells (granulocyte CFU, erythroid burst-forming units/CFU and megakayocyte CFU) after 8 and 12 d of culture. Six weeks after transplanting 12 d-expanded cells to non-obese diabetic severe combined immunodeficient mice, increased engraftment of human CD45+ cells was observed in the bone marrow of animals that received NTL-treated cells. The dual functions of NTL on long-term preservation and expansion of early stem/multilineage progenitor cells could be developed for applications in various cell therapy strategies, such as the clinical expansion of CD34+ cells for transplantation.
British Journal of Haematology 02/2008; 140(1):90-8. · 4.94 Impact Factor