title: Involvement of CSF-1 in generating a stroma-independent hematopoietic stem cell line.
abstract: The hematopoietic stem cell line, Myl-D7, is maintained by a self-renewing stem cell population that spontaneously generates myeloid, lymphoid, and erythroid progeny. MS-5 stromal cells are necessary for the growth of Myl-D7 cells. One component of the Myl-D7 cells proliferation activity released by MS-5 stromal cells was enriched by Q sepharose fractionation and shown to be colony stimulating factor-1 (CSF-1) by Western blotting, BAC1.2F5 cell bioassay and inhibition of Myl-D7 proliferation by CSF-1 antibody. The requirement of Myl-D7 cells for CSF-1 was also demonstrated independently by selecting for rare, stroma-independent Myl-D7 mutant clones able to grow without stroma and additional factors. Eighty-nine stroma-independent mutant clones were obtained and belonged to two classes. The majority of mutants did not secrete any growth promoting activity. The second, rarer class of mutants releases a factor that stimulates proliferation/survival for up to several months and approximately half of the secretors express high levels of CSF-1 mRNA. Wild type Myl-D7 grown with supernatants from the secretor cells retained the stem cell phenotype. These data suggest that CSF-1 may act as a key factor in stroma-regulated hematopoiesis and cell-cell interaction.
authors.affiliation: CellTec GmbH, Frohmestrasse, Hamburg, Germany.
authors.forename: Christoph
authors.initials: C
authors.lastname: Heberlein
authors.forename: Jutta
authors.initials: J
authors.lastname: Friel
authors.forename: Katsuhiko
authors.initials: K
authors.lastname: Itoh
authors.forename: Eugene
authors.initials: E
authors.lastname: Medlock
authors.forename: Luke
authors.initials: L
authors.lastname: Li
authors.forename: Naoki
authors.initials: N
authors.lastname: Nakayama
authors.forename: Carol
authors.initials: C
authors.lastname: Stocking
authors.forename: Maren
authors.initials: M
authors.lastname: Geldmacher
authors.forename: Wolfram
authors.initials: W
authors.lastname: Ostertag
mesh_terms: D000818:Animals; D002458:Cell Fractionation; D002460:Cell Line; D049109:Cell Proliferation; D002999:Clone Cells / Q000378:metabolism*; D017077:Culture Media, Conditioned / Q000737:chemistry / Q000378:metabolism*; D006133:Growth Substances / Q000378:metabolism / Q000502:physiology; D006412:Hematopoietic Stem Cells; D016173:Macrophage Colony-Stimulating Factor / Q000502:physiology*; D051379:Mice; D017154:Stromal Cells
chemical_list: D017077:Culture Media, Conditioned; D006133:Growth Substances; D016173:Macrophage Colony-Stimulating Factor