Abstract
Hematopoietic stem cells (HSCs) are maintained in an undifferentiated quiescent state within a bone marrow niche. Here we show that Foxo3a, a forkhead transcription factor that acts downstream of the PTEN/PI3K/Akt pathway, is critical for HSC self-renewal. We generated gene-targeted Foxo3a-/- mice and showed that, although the proliferation and differentiation of Foxo3a-/- hematopoietic progenitors were normal, the number of colony-forming cells present in long-term cocultures of Foxo3a-/- bone marrow cells and stromal cells was reduced. The ability of Foxo3a-/- HSCs to support long-term reconstitution of hematopoiesis in a competitive transplantation assay was also impaired. Foxo3a-/- HSCs also showed increased phosphorylation of p38MAPK, an elevation of ROS, defective maintenance of quiescence, and heightened sensitivity to cell-cycle-specific myelotoxic injury. Finally, HSC frequencies were significantly decreased in aged Foxo3a-/- mice compared to the littermate controls. Our results demonstrate that Foxo3a plays a pivotal role in maintaining the HSC pool.
Original language | English (US) |
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Pages (from-to) | 101-112 |
Number of pages | 12 |
Journal | Cell Stem Cell |
Volume | 1 |
Issue number | 1 |
DOIs | |
State | Published - Jun 7 2007 |
Externally published | Yes |
ASJC Scopus subject areas
- Molecular Medicine
- Genetics
- Cell Biology