title: Stromal cell-derived factor-1 (SDF-1) acts together with thrombopoietin to enhance the development of megakaryocytic progenitor cells (CFU-MK).
abstract: Stromal cell-derived factor-1 (SDF-1) is a CXC chemokine that acts as a stimulator of pre-B lymphocyte cell growth and as a chemoattractant for T cells, monocytes, and hematopoietic stem cells. More recent studies also suggest that megakaryocytes migrate in response to SDF-1. Because genetic elimination of SDF-1 or its receptor lead to marrow aplasia, we investigated the effect of SDF-1 on megakaryocyte progenitors (colony-forming units-megakaryocyte [CFU-MK]). We report that SDF-1 augments the growth of CFU-MK from whole murine bone marrow cells when combined with thrombopoietin (TPO). The addition of SDF-1 to interleukin-3 (IL-3) or stem cell factor (SCF) had no effect. Specific antagonists for CXCR4 (the sole receptor for SDF-1), T22, and 1-9 (P2G) SDF-1 reduced megakaryocyte colony growth induced by TPO alone, suggesting that many culture systems contain endogenous levels of the chemokine that contributes to the TPO effect. To examine whether SDF-1 has direct effects on CFU-MK, we developed a new protocol to purify megakaryocyte progenitors. CFU-MK were highly enriched in CD41(high) c-kit(high) cells generated from lineage-depleted TPO-primed marrow cells. Because the growth-promoting effects of SDF-1 were also observed when highly purified populations of CFU-MK were tested in serum-free cultures, these results suggest that SDF-1 directly promotes the proliferation of megakaryocytic progenitors in the presence of TPO, and in this way contributes to the favorable effects of the bone marrow microenvironment on megakaryocyte development.
authors.affiliation: Division of Hematology, University of Washington School of Medicine, Seattle 98195-7710, USA.
authors.forename: K
authors.initials: K
authors.lastname: Hodohara
authors.forename: N
authors.initials: N
authors.lastname: Fujii
authors.forename: N
authors.initials: N
authors.lastname: Yamamoto
authors.forename: K
authors.initials: K
authors.lastname: Kaushansky
mesh_terms: D000818:Animals; D002454:Cell Differentiation / Q000187:drug effects; D002455:Cell Division / Q000187:drug effects; D019070:Cell Lineage; D002469:Cell Separation / Q000379:methods; D002478:Cells, Cultured; D002499:Centrifugation, Density Gradient; D054377:Chemokine CXCL12; D019743:Chemokines, CXC / Q000494:pharmacology*; D003114:Colony-Forming Units Assay; D005434:Flow Cytometry; D006410:Hematopoiesis / Q000187:drug effects*; D006412:Hematopoietic Stem Cells / Q000166:cytology / Q000187:drug effects*; D006801:Humans; D007377:Interleukin-3 / Q000494:pharmacology; D008533:Megakaryocytes / Q000166:cytology*; D051379:Mice; D019039:Platelet Glycoprotein GPIIb-IIIa Complex / Q000032:analysis; D011003:Ploidies; D051381:Rats; D019718:Receptors, CXCR4 / Q000187:drug effects; D011993:Recombinant Fusion Proteins / Q000494:pharmacology; D019089:Stem Cell Factor / Q000494:pharmacology; D013926:Thrombopoietin / Q000494:pharmacology*
chemical_list: C515255:CXCL12 protein, human; D054377:Chemokine CXCL12; D019743:Chemokines, CXC; C515256:Cxcl12 protein, mouse; D007377:Interleukin-3; D019039:Platelet Glycoprotein GPIIb-IIIa Complex; D019718:Receptors, CXCR4; D011993:Recombinant Fusion Proteins; D019089:Stem Cell Factor; D013926:Thrombopoietin