title: Human Cord Blood and Bone Marrow CD34+ Cells Generate Macrophages That Support Erythroid Islands.
abstract: Recently, we developed a small molecule responsive hyperactive Mpl-based Cell Growth Switch (CGS) that drives erythropoiesis associated with macrophages in the absence of exogenous cytokines. Here, we compare the physical, cellular and molecular interaction between the macrophages and erythroid cells in CGS expanded CD34+ cells harvested from cord blood, marrow or G-CSF-mobilized peripheral blood. Results indicated that macrophage based erythroid islands could be generated from cord blood and marrow CD34+ cells but not from G-CSF-mobilized CD34+ cells. Additional studies suggest that the deficiency resides with the G-CSF-mobilized CD34+ derived monocytes. Gene expression and proteomics studies of the in vitro generated erythroid islands detected the expression of erythroblast macrophage protein (EMP), intercellular adhesion molecule 4 (ICAM-4), CD163 and DNASE2. 78% of the erythroblasts in contact with macrophages reached the pre reticulocyte orthochromatic stage of differentiation within 14 days of culture. The addition of conditioned medium from cultures of CD146+ marrow fibroblasts resulted in a 700-fold increase in total cell number and a 90-fold increase in erythroid cell number. This novel CD34+ cell derived erythroid island may serve as a platform to explore the molecular basis of red cell maturation and production under normal, stress and pathological conditions.
authors.affiliation: Clinical Research Division, Fred Hutchinson Cancer Research Center, Seattle, Washington, United States of America.
authors.forename: Eyayu
authors.initials: E
authors.lastname: Belay
authors.affiliation: Clinical Research Division, Fred Hutchinson Cancer Research Center, Seattle, Washington, United States of America.
authors.forename: Brian J
authors.initials: BJ
authors.lastname: Hayes
authors.affiliation: Department of Medicine, Division of Hematology, University of Washington, Seattle, Washington, United States of America.|Institute for Stem Cell and Regenerative Medicine, University of Washington, Seattle, Washington, United States of America.
authors.forename: C Anthony
authors.initials: CA
authors.lastname: Blau
authors.affiliation: Clinical Research Division, Fred Hutchinson Cancer Research Center, Seattle, Washington, United States of America.
authors.forename: Beverly
authors.initials: B
authors.lastname: Torok-Storb
mesh_terms: D018952:Antigens, CD34 / Q000378:metabolism*; D001854:Bone Marrow Cells / Q000166:cytology* / Q000187:drug effects; D002450:Cell Communication / Q000187:drug effects; D002454:Cell Differentiation / Q000187:drug effects; D002455:Cell Division / Q000187:drug effects; D049109:Cell Proliferation / Q000187:drug effects; D018920:Coculture Techniques; D017077:Culture Media, Conditioned / Q000494:pharmacology; D004900:Erythroblasts / Q000166:cytology / Q000187:drug effects; D041905:Erythroid Cells / Q000166:cytology* / Q000187:drug effects; D005312:Fetal Blood / Q000166:cytology*; D005786:Gene Expression Regulation / Q000187:drug effects; D016179:Granulocyte Colony-Stimulating Factor / Q000494:pharmacology; D006801:Humans; D008264:Macrophages / Q000166:cytology* / Q000187:drug effects; D009000:Monocytes / Q000166:cytology / Q000187:drug effects; D019010:Vascular Cell Adhesion Molecule-1 / Q000378:metabolism
chemical_list: D018952:Antigens, CD34; D017077:Culture Media, Conditioned; D019010:Vascular Cell Adhesion Molecule-1; D016179:Granulocyte Colony-Stimulating Factor