title: Cyclophosphamide/granulocyte colony-stimulating factor induces hematopoietic stem cells to proliferate prior to mobilization.
abstract: We isolated hematopoietic stem cells (HSC) from mice treated with cyclophosphamide (CY) and granulocyte colony-stimulating factor (G-CSF). All mobilized multipotent progenitor activity was contained in two populations: Thy-1(lo) Sca-1+ Lin- Mac-1- CD4- c-kit+ long-term reconstituting progenitors and Thy-1(lo) Sca-1+ Lin- Mac-1(lo) CD4- transiently reconstituting progenitors. CY/G-CSF treatment drove both long-term and transient multipotent progenitors into cycle, leading to a more than 12-fold expansion in the number of long-term self-renewing HSC prior to mobilization. After CY and 2 days of G-CSF treatment the number of bone marrow HSC began to decline and the number of blood and splenic HSC increased. HSC continued to proliferate in the bone marrow and spleen through 8 days of G-CSF treatment, but HSC released into the blood tended to be in G0/G1 phase. Mobilized multipotent progenitors isolated from the spleen were less efficient than normal bone marrow multipotent progenitors in engrafting irradiated mice but did not differ in colony forming unit-spleen (CFU-S) activity or single cell in vitro assays of primitive progenitor activity. The data suggest that mobilized HSC isolated from the spleen are less efficient at homing to and engrafting the bone marrow of irradiated recipient mice.
authors.affiliation: Department of Pathology, Stanford University, CA 94305, USA. morrisonS@starbase1.caltech.edu
authors.forename: S J
authors.initials: SJ
authors.lastname: Morrison
authors.forename: D E
authors.initials: DE
authors.lastname: Wright
authors.forename: I L
authors.initials: IL
authors.lastname: Weissman
mesh_terms: D000818:Animals; D000943:Antigens, Differentiation / Q000032:analysis; D000954:Antigens, Surface / Q000032:analysis; D001853:Bone Marrow / Q000187:drug effects; D001854:Bone Marrow Cells; D016026:Bone Marrow Transplantation; D015704:CD4 Antigens / Q000032:analysis; D002454:Cell Differentiation / Q000502:physiology; D002455:Cell Division / Q000187:drug effects; D002465:Cell Movement; D003520:Cyclophosphamide / Q000494:pharmacology*; D016178:Granulocyte-Macrophage Colony-Stimulating Factor / Q000494:pharmacology*; D018380:Hematopoietic Stem Cell Transplantation; D006412:Hematopoietic Stem Cells / Q000145:classification / Q000166:cytology* / Q000187:drug effects / Q000502:physiology; D016177:Macrophage-1 Antigen / Q000032:analysis; D051379:Mice; D008810:Mice, Inbred C57BL; D019009:Proto-Oncogene Proteins c-kit / Q000032:analysis; D011839:Radiation, Ionizing; D013154:Spleen / Q000166:cytology / Q000187:drug effects; D018800:Thy-1 Antigens / Q000032:analysis
chemical_list: D000943:Antigens, Differentiation; D000954:Antigens, Surface; D015704:CD4 Antigens; D016177:Macrophage-1 Antigen; D018800:Thy-1 Antigens; C047076:senescent cell differentiation antigen; D016178:Granulocyte-Macrophage Colony-Stimulating Factor; D003520:Cyclophosphamide; D019009:Proto-Oncogene Proteins c-kit