title: Steel factor coordinately regulates the molecular signature and biologic function of hematopoietic stem cells.
abstract: Hematopoietic stem cells (HSCs) regenerated in vivo display sustained differences in their self-renewal and differentiation activities. Variations in Steel factor (SF) signaling are known to affect these functions in vitro, but the cellular and molecular mechanisms involved are not understood. To address these issues, we evaluated highly purified HSCs maintained in single-cell serum-free cultures containing 20 ng/mL IL-11 plus 1, 10, or 300 ng/mL SF. Under all conditions, more than 99% of the cells traversed a first cell cycle with similar kinetics. After 8 hours in the 10 or 300 ng/mL SF conditions, the frequency of HSCs remained unchanged. However, in the next 8 hours (ie, 6 hours before any cell divided), HSC integrity was sustained only in the 300 ng/mL SF cultures. The cells in these cultures also contained significantly higher levels of Bmi1, Lnk, and Ezh2 transcripts but not of several other regulators. Assessment of 21 first division progeny pairs further showed that only those generated in 300 ng/mL SF cultures contained HSCs and pairs of progeny with similar differentiation programs were not observed. Thus, SF signaling intensity can directly and coordinately alter the transcription factor profile and long-term repopulating ability of quiescent HSCs before their first division.
authors.affiliation: Terry Fox Laboratory, British Columbia Cancer Agency, Vancouver, BC, Canada.
authors.forename: David G
authors.initials: DG
authors.lastname: Kent
authors.forename: Brad J
authors.initials: BJ
authors.lastname: Dykstra
authors.forename: Jay
authors.initials: J
authors.lastname: Cheyne
authors.forename: Elaine
authors.initials: E
authors.lastname: Ma
authors.forename: Connie J
authors.initials: CJ
authors.lastname: Eaves
mesh_terms: D048868:Adaptor Proteins, Signal Transducing; D000818:Animals; D002453:Cell Cycle / Q000187:drug effects; D002478:Cells, Cultured; D004305:Dose-Response Relationship, Drug; D000071221:Enhancer of Zeste Homolog 2 Protein; D018380:Hematopoietic Stem Cell Transplantation; D006412:Hematopoietic Stem Cells / Q000166:cytology / Q000187:drug effects*; D011495:Histone-Lysine N-Methyltransferase; D047908:Intracellular Signaling Peptides and Proteins; D007700:Kinetics; D008565:Membrane Proteins; D051379:Mice; D009687:Nuclear Proteins / Q000235:genetics; D063150:Polycomb Repressive Complex 1; D063151:Polycomb Repressive Complex 2; D011506:Proteins / Q000235:genetics; D011518:Proto-Oncogene Proteins / Q000235:genetics; D012333:RNA, Messenger / Q000032:analysis; D012097:Repressor Proteins / Q000235:genetics; D019089:Stem Cell Factor / Q000494:pharmacology*
chemical_list: D048868:Adaptor Proteins, Signal Transducing; C489421:Bmi1 protein, mouse; D047908:Intracellular Signaling Peptides and Proteins; C490777:Lnk protein, mouse; D008565:Membrane Proteins; D009687:Nuclear Proteins; D011506:Proteins; D011518:Proto-Oncogene Proteins; D012333:RNA, Messenger; D012097:Repressor Proteins; D019089:Stem Cell Factor; D000071221:Enhancer of Zeste Homolog 2 Protein; C498410:Ezh2 protein, mouse; D011495:Histone-Lysine N-Methyltransferase; D063151:Polycomb Repressive Complex 2; D063150:Polycomb Repressive Complex 1