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GSE14361
Mus musculus
5 Downloadable Samples
Description
Maintenance of the blood system is dependent on dormant haematopoietic stem cells (HSCs) with long-term self-renewal capacity. Upon injury these cells are induced to proliferate in order to quickly re-establish homeostasis. The signalling molecules promoting the exit of HSCs out of the dormant stage remain largely unknown. Here we show that in response to treatment of mice with interferon-alpha (IFN), HSCs efficiently exit G0 and enter an active cell cycle. HSCs respond to IFN treatment by increased phosphorylation of STAT1 and PKB/Akt, expression of IFN target genes and up-regulation of stem cell antigen-1 (Sca-1). HSCs lacking either the interferon-/ receptor (IFNAR), STAT1 or Sca-1 are insensitive to IFN stimulation, demonstrating that STAT1 and Sca-1 mediate IFN induced HSC proliferation. Although dormant HSCs are resistant to the anti-proliferative chemotherapeutic agent 5-FU1, HSCs pre-treated (primed) with IFN and thus induced to proliferate are efficiently eliminated by 5-FU exposure in vivo. Conversely, HSCs chronically activated by IFN are functionally compromised and are rapidly out competed by non-activatable IFNAR-/- cells in competitive repopulation assays. In summary, while chronic activation of the IFN pathway in HSCs impairs their function, acute IFN treatment promotes the proliferation of dormant HSCs in vivo. These data may help to clarify the so far unexplained clinical effects of IFN on leukemic cells and raise the possibility for novel applications of type I interferons to target cancer stem cells.
Publication Title
IFNalpha activates dormant haematopoietic stem cells in vivo.
Sample Metadata Fields
Specimen part, Time
View Samples- Mus musculus
- 6 Downloadable Samples
Description
Bone marrow hematopoietic stem cells (HSCs) are crucial to maintain lifelong production of all blood cells. Although HSCs divide infrequently, it is thought that the entire HSC pool turns over every few weeks, suggesting that HSCs regularly enter and exit cell cycle. Here, we combine flow cytometry with label-retaining assays (BrdU and histone H2B-GFP) to identify a population of dormant mouse HSCs (d-HSCs) within the lin(-)Sca1+cKit+CD150+CD48(-)CD34(-) population. Computational modeling suggests that d-HSCs divide about every 145 days, or five times per lifetime. d-HSCs harbor the vast majority of multilineage long-term self-renewal activity. While they form a silent reservoir of the most potent HSCs during homeostasis, they are efficiently activated to self-renew in response to bone marrow injury or G-CSF stimulation. After re-establishment of homeostasis, activated HSCs return to dormancy, suggesting that HSCs are not stochastically entering the cell cycle but reversibly switch from dormancy to self-renewal under conditions of hematopoietic stress
Publication Title
Hematopoietic stem cells reversibly switch from dormancy to self-renewal during homeostasis and repair.
Sample Metadata Fields
Specimen part, Time
View Samples