| Institution: | 1. Team 9 (Equipe labellisée Ligue Nationale contre le Cancer), Centre de Recherche en Cancérologie Nantes-Angers, UMR INSERM 892/CNRS UMR 6299, F-44007 Nantes, France;2. Université de Nantes, Faculté de Médecine, 9 Quai Moncousu, 44035 Nantes Cedex 01, France;3. CHU de Nantes, 1 place Alexis-Ricordeau, 44093 Nantes Cedex 1, France;4. Institut de Cancérologie de l''Ouest, Centre René Gauducheau, Saint Herblain, France;1. Center for Regenerative Medicine, Massachusetts General Hospital, Boston, MA, USA;2. Harvard Stem Cell Institute, Cambridge, MA, USA;3. Department of Stem Cell and Regenerative Biology, Harvard University, Cambridge, MA, USA |
| Abstract: | Myeloid progenitors reside within specific hematopoietic organs and commit to progenitor lineages bearing megakaryocyte/erythrocyte (MEP) or granulocyte/macrophage potentials (GMP) within these sites. Unlike other vertebrates, the amphibian Xenopus laevis committed macrophage precursors are absent from the hematopoietic subcapsular liver and instead reside within their bone marrow. Presently, we demonstrate that while these frogs’ liver-derived cells are unresponsive to recombinant forms of principal X. laevis macrophage (colony-stimulating factor-1; CSF-1) and granulocyte (CSF-3) growth factors, bone marrow cells cultured with CSF-1 and CSF-3 exhibit respectively archetypal macrophage and granulocyte morphology, gene expression and functionalities. Moreover, we demonstrate that liver, but not bone marrow cells possess erythropoietic capacities when stimulated with a X. laevis erythropoietin. Together, our findings indicate that X. laevis retain their MEP within the hematopoietic liver while sequestering their GMP to the bone marrow, thus marking a very novel myelopoietic strategy as compared to those seen in other jawed vertebrate species. |
