title: Dominant myelopoietic effector functions mediated by chemokine receptor CCR1.
abstract: Macrophage inflammatory protein (MIP)-1alpha, a CC chemokine, enhances proliferation of mature subsets of myeloid progenitor cells (MPCs), suppresses proliferation of immature MPCs, and mobilizes mature and immature MPCs to the blood. MIP-1alpha binds at least three chemokine receptors. To determine if CCR1 was dominantly mediating the above activities of MIP-1alpha, CCR1-deficient (-/-) mice, produced by targeted gene disruption, were used. MIP-1alpha enhanced colony formation of marrow granulocyte/macrophage colony-forming units (CFU-GM), responsive to stimulation by granulocyte/macrophage colony-stimulating factor (GM-CSF), and CFU-M, responsive to stimulation by M-CSF, from littermate control CCR1(+/+) but not CCR1(-/-) mice. Moreover, MIP-1alpha did not mobilize MPCs to the blood or synergize with G-CSF in this effect in CCR1(-/-) mice. However, CCR1(-/-) mice were increased in sensitivity to MPC mobilizing effects of G-CSF. Multi-growth factor-stimulated MPCs in CCR1(-/-) and CCR1(+/+) marrow were equally sensitive to inhibition by MIP-1alpha. These results implicate CCR1 as a dominant receptor for MIP-1alpha enhancement of proliferation of lineage-committed MPCs and for mobilization of MPCs to the blood. CCR1 is not a dominant receptor for MIP-1alpha suppression of MPC proliferation, but it does negatively impact G-CSF-induced MPC mobilization.
authors.affiliation: Department of Microbiology/Immunology, the Department of Medicine, and the Walther Oncology Center, Indiana University School of Medicine, Indianapolis, Indiana 46202, USA. hbroxmey@iupui.edu
authors.forename: H E
authors.initials: HE
authors.lastname: Broxmeyer
authors.forename: S
authors.initials: S
authors.lastname: Cooper
authors.forename: G
authors.initials: G
authors.lastname: Hangoc
authors.forename: J L
authors.initials: JL
authors.lastname: Gao
authors.forename: P M
authors.initials: PM
authors.lastname: Murphy
mesh_terms: D000818:Animals; D002455:Cell Division / Q000187:drug effects; D054405:Chemokine CCL3; D054407:Chemokine CCL4; D018925:Chemokines / Q000494:pharmacology; D003114:Colony-Forming Units Assay; D015672:Erythroid Precursor Cells / Q000378:metabolism; D016178:Granulocyte-Macrophage Colony-Stimulating Factor / Q000494:pharmacology; D006801:Humans; D019891:Leukopoiesis / Q000187:drug effects*; D019402:Macrophage Inflammatory Proteins / Q000494:pharmacology*; D051379:Mice; D018345:Mice, Knockout; D054389:Receptors, CCR1; D019707:Receptors, Chemokine / Q000235:genetics / Q000378:metabolism*; D013234:Stem Cells / Q000187:drug effects*
chemical_list: C515300:CCR1 protein, human; C515301:Ccr1 protein, mouse; D054405:Chemokine CCL3; D054407:Chemokine CCL4; D018925:Chemokines; D019402:Macrophage Inflammatory Proteins; D054389:Receptors, CCR1; D019707:Receptors, Chemokine; D016178:Granulocyte-Macrophage Colony-Stimulating Factor