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GSE16100
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- 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
- 20 Downloadable Samples
Description
The Forkhead family of transcription factors comprises numerous members and is implicated in various cellular functions, including cell growth, apoptosis, migration and differentiation.In this study we identified the Forkhead factor FoxQ1 as increased in expression during TGF-beta1 induced changes in epithelial differentiation, suggesting functional roles of FoxQ1 for epithelial plasticity.The repression of FoxQ1 in mammary epithelial cells led to a change in cell morphology characterized by an increase in cell size, pronounced cell-cell contacts and an increased expression of several junction proteins (e.g. E-cadherin). In addition, FoxQ1 knock-down cells revealed rearrangements in the actin-cytoskeleton and slowed down cell cycle G1-phase progression.Furthermore, repression of FoxQ1 enhanced the migratory capacity of coherent mammary epithelial cells.Gene expression profiling of NM18 cells indicated that FoxQ1 is a relevant downstream mediator of TGF-beta1 induced gene expression changes. This included the differential expression of transcription factors involved in epithelial plasticity, e.g. Ets-1, Zeb1 and Zeb2.In summary, this study has elucidated the functional impact of FoxQ1 on epithelial differentiation
Publication Title
No associated publication
Sample Metadata Fields
Specimen part, Treatment
View Samples- Mus musculus
- 15 Downloadable Samples
Description
To understand differences between resting and activated memory CD8+ T cells, we compared the global gene expression of ex vivo isolated naive and spleen and BM memory cells to in vitro activated spleen and BM memory cells.
Publication Title
Memory CD8(+) T cells colocalize with IL-7(+) stromal cells in bone marrow and rest in terms of proliferation and transcription.
Sample Metadata Fields
Sex, Specimen part
View Samples- Mus musculus
- 6 Downloadable Samples
Description
Upon immunization with a T cell dependent antigen naive follicular B cells (Fo) are activated and a germinal center reaction is induced. Within the next 2 weeks large germinal centers develop where the process of affinity maturation takes place. To analyze the gene expression profile of resting and activated B cells, follicular B cells (Fo), B cells from early (GC1) and late germinal centers (GC2) were isolated and their gene expression profile compared.
Publication Title
No associated publication
Sample Metadata Fields
Sex, Specimen part
View Samples- Mus musculus
- 6 Downloadable Samples
Description
CD4+ T lymphocytes are key to immunological memory, but little is known about the lifestyle of memory CD4+ T lymphocytes. We showed that in the memory phase of specific immune responses to antigens, most of the memory CD4+ T lymphocytes relocated into the bone marrow (BM) within 3-8 weeks after their generation, a process involving integrin a2. Antigen-specific memory CD4+ T lymphocytes expressed Ly-6C to a high degree, unlike most splenic CD44hiCD62L- CD4+ T lymphocytes. In adult mice, more than 80% of Ly-6Chi CD44hiCD62L- memory CD4+ T lymphocytes were in the BM. In the BM, they are located next to IL-7-expressing VCAM-1+ stroma cells, and were in a resting state. Upon challenge with antigen, they rapidly expressed cytokines and CD154 and induced the production of high-affinity antibodies, indicating their functional activity in vivo and marking them as professional memory T helper cells
Publication Title
No associated publication
Sample Metadata Fields
Specimen part
View Samples- Mus musculus
- 6 Downloadable Samples
Description
Hopx appears to be needed for persistence of Th1 effector memory cells. IFN-gamma-producing Th cells are significantly reduced in Hopx-deficient mice compared to Hopx-expressing littermates and Hopx-deficient Th1 cells show a defective persistence upon adoptive transfer. Moreover, Hopx protects Th1 cells from Fas-mediated cell death in vitro. To further dissect the role of Hopx and to identify target genes of Hopx, we have performed transcriptome analysis to compare gene expression in Hopx-deficient versus Hopx-competent Th1 cells. In agreement with the role of Hopx in supporting survival of Th1 effector memory cells, anti-apoptotic cells were up-regulated and pro-apoptotic genes were down-regulated in Hopx-competent compared to Hopx-deficient Th1 cells.
Publication Title
Persistence of effector memory Th1 cells is regulated by Hopx.
Sample Metadata Fields
Sex, Specimen part
View Samples- Homo sapiens
- 285 Downloadable Samples
- Affymetrix Human Gene 1.1 ST Array (hugene11st)
Description
Affymetrix Human Gene 1.1 ST Array profiling of 285 primary medulloblastoma samples.
Publication Title
Subgroup-specific structural variation across 1,000 medulloblastoma genomes.
Sample Metadata Fields
Sex, Age
View Samples