Environmental Optimization Enables Maintenance of Quiescent Hematopoietic Stem Cell Ex Vivo
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PROVIDER: PRJNA482379 | ENA |
REPOSITORIES: ENA
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Project description:Hematopoietic stem cells (HSCs) maintain lifelong hematopoiesis by remaining quiescent in the bone marrow niche. Recapitulation of a quiescent state in culture has not been achieved, as cells rapidly proliferate and differentiate in vitro. By modulating environmental factors mimicking physiological conditions, we were able to maintain engraftable quiescent HSCs for 1 month in culture under low cytokine concentrations, hypoxia, and high fatty acid concentration, the latter required due to suppression of intrinsic fatty acid synthesis. By contrast, high cytokine concentrations or normoxia induced HSC proliferation and differentiation. Our novel culture system provides a means to evaluate properties of steady state HSCs and test effects of defined factors in vitro under near-physiological conditions.
2018-07-24 | GSE117516 | GEO
Project description:Cancer stem cells (CSCs) are profoundly associated with refractory nature of cancer. A quiescent population of CSCs is responsible for tumorigenesis and chemoresistance in leukemia, whereas neither the presence nor clinical importance of the quiescent CSCs is clearly established in solid tumors. In colon cancer, LGR5 is regarded as a functional marker of CSCs, but heterogeneity among LGR5+ cells was not clearly defined. Here we stratified LGR5+ cells by single-cell gene expression analyses and revealed that a tumorigenic population of mouse LGR5+ cells resides in a quiescent state. We identified 23 signature genes that were uniquely expressed in the quiescent CSCs of mouse tumors, and found that 7 of them were also specifically expressed in a quiescent population of LGR5+ cells in human colon xenograft tumors. Among them, PROX1 was expressed in invasive fronts of colon tumors. PROX1 was induced by TCF1 (TCF7), and the TCF1-mediated PROX1 expression was responsible for not only the maintenance of quiescence but also chemoresistance of colon cancer organoids. Knockout of PROX1 in patient-derived xenograft tumors resulted in inhibition of tumor recurrence after chemotherapeutic treatment. Our data underscore the therapeutic importance of a quiescent CSC population in colon cancer.
2019-11-30 | GSE141157 | GEO
Project description:This SuperSeries is composed of the following subset Series: GSE8542: BY4742 Quiescent and Non-quiescent replicates GSE8558: Proteinase K treatment of Q and NQ cells GSE8559: S288c Quiescent and Non-quiescent replicates GSE8560: Mutant1 GSE8561: Mutant2 Refer to individual Series
2010-05-29 | E-GEOD-8624 | biostudies-arrayexpress
Project description:Many stem cell populations exist in a quiescent state in vivo, exiting quiescence and entering the cell cycle in response to specific stimuli. In the case of skeletal muscle, the muscle stem cells (MuSCs, or “satellite cells”) are quiescent under normal homeostatic conditions and undergo activation and cell cycle entry in response to muscle fiber damage. Quiescent MuSCs are also much more potent than their proliferating progeny in assays of stem cell transplantation. In recent years, it has become increasingly apparent that the quiescent state is both actively maintained and dynamically regulated. However, most of the analyses of quiescent MuSCs have come from cells that have been removed from their niche in vivo, purified by fluorescence activated cell sorting, and then assay ex vivo. Although such cells are still in the quiescent state under these conditions, there is no doubt that significant biochemical changes will occur during the isolation and purification process. Thus, we have sought to examine the true in vivo quiescent state by analyzing the transcriptome of MuSCs. To achieve that, we have used techniques to label actively transcribing RNA in vivo using nucleoside analogs. In mice in which the enzyme uracil phosphoribosyltransferase (UPRT) is expressed specifically in MuSCs, administration of 4-thiouracil (4TU), which is converted to thiouridine (TU) by UPRT, resulted in labelling of MuSC transcripts, and the transcriptome could be analyzed following pull-down of TU-tagged RNA. Varying the timing of 4TU administration revealed the dynamic regulation of different subsets of transcripts. Notably, labeling transcripts during the isolation procedure revealed very active transcription of specific subsets of genes. Nevertheless, the ex vivo transcriptome remained largely reflective of the in vivo transcriptome. Using the transcriptional inhibitor, α-amanitin, we were also able to show that there was little difference between the steady-state transcript levels of the most highly expressed genes when comparing the ex vivo transcriptome with the in vivo transcriptome. Together, these data provide a novel view of the molecular regulation of the quiescent state at the transcriptional level, demonstrate the utility of these tools for probing transcriptional dynamics in vivo, and provide an invaluable resource for understanding stem cell state transitions.
2017-11-12 | GSE97399 | GEO
Project description:Gene expression after mammosphere culture, quiescent single cells
| EGAD00010001964 | EGA
Project description:Pre-Amplification Assay Optimization for Low RNA Inputs and Single Cells Low Input Total RNA
2012-02-27 | E-GEOD-34364 | biostudies-arrayexpress
Project description:ATAC-seq has been used for mapping open chromatin regions. Here we summarize our optimization methods.
2022-05-14 | GSE202791 | GEO
Project description:Background: With the growing availability of entire genome sequences, an increasing number of scientists can exploit oligonucleotide microarrays for genome-scale expression studies. While probe-design is a major research area, relatively little work has been reported on the optimization of microarray protocols. Results: As shown in this study, suboptimal conditions can have considerable impact on biologically relevant observations. For example, deviation from the optimal temperature by one degree Celsius lead to a loss of 44% of differentially expressed genes identified. While genes from thousands of Gene Ontology categories were affected, transcription factors and other low-copy-number regulators were disproportionately lost. Calibrated protocols are thus required in order to take full advantage of the large dynamic range of microarrays. For an objective optimization of protocols we introduce an approach that maximizes the amount of information obtained per experiment. A comparison of two typical samples is sufficient for this calibration. We ensure, however, that optimization results are independent of the samples and the specific measures used for calibration. Both simulations and spike-in experiments confirm an unbiased determination of generally optimal experimental conditions. Conclusions: Well calibrated hybridization conditions are thus easily achieved and necessary for the efficient detection of differential expression. They are essential for the sensitive profiling of low-copy-number molecules. This is particularly critical for studies of transcription factor expression, or the inference and study of regulatory networks. Supporting material, including source code and data, is available at http://bioinf.boku.ac.at/pub/optMA2010/. Optimization of hybridization temperature via an assessment of differential expression between two samples (male vs female Drosophila melanogaster) in 6 technical replicates (3 regular + 3 dye-swaps) for hybridizations at different temperatures (in two batches of 50, 52, 54, and 56; and 47, 49, 50, and 51 degree Celsius, with the repeated hybridization at 50 degree Celsius serving to demonstrate batch-to-batch stability).
2011-11-11 | E-GEOD-25625 | biostudies-arrayexpress