Loss of immune function and an increased incidence of myeloid leukemia are two of the most clinically significant consequences of aging of the hematopoietic system. To better understand the mechanisms underlying hematopoietic aging, we evaluated the cell intrinsic functional and molecular properties of highly purified long-term hematopoietic stem cells (LT-HSCs) from young and old mice. We found that LT-HSC aging was accompanied by cell autonomous changes, including increased stem cell self-renewal, differential capacity to generate committed myeloid and lymphoid progenitors, and diminished lymphoid potential. Expression profiling revealed that LT-HSC aging was accompanied by the systemic down-regulation of genes mediating lymphoid specification and function and up-regulation of genes involved in specifying myeloid fate and function. Moreover, LT-HSCs from old mice expressed elevated levels of many genes involved in leukemic transformation. These data support a model in which age-dependent alterations in gene expression at the stem cell level presage downstream developmental potential and thereby contribute to age-dependent immune decline, and perhaps also to the increased incidence of leukemia in the elderly.
Cell intrinsic alterations underlie hematopoietic stem cell aging.
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View SamplesGene expression profiles in blasts from three APL patients expressing PML/RAR were assessed before and after treatment with 1 uM retinoic acid (RA) in vitro for four hours. We then studied a U937 clone conditionally expressing PML/RAR (U937-PR), (Grignani et al. 1993) (Alcalay et al. 2003), and compared the gene expression profile prior to and after 4 hours of treatment with 1 uM RA, to that obtained from a cell line bearing an empty vector (U937-MT). For each sample, biotinylated cRNA targets were synthesized starting from 5ug of total RNA, and hybridized to the complete set of HG-U133 Affymetrix oligonucleotide chips, which explores the expression of approximately 45,000 human transcripts. Results were analyzed using MASv5 and further elaborated with the GenePicker software. GeneChip probe sets regulated by RA in each sample were clustered into non-redundant regulated genes according to UniGene release Hs.166.
Molecular signature of retinoic acid treatment in acute promyelocytic leukemia.
Specimen part, Disease, Cell line, Subject, Compound
View SamplesWe analyzed gene expression in 184 (finite life span) and HMT3522 S1 (immortal non-malignant) HMECs on successive days (3, 5, and 7) post-seeding in a laminin-rich extracellular matrix assay. Both HMECs underwent growth arrest in G0/G1 and differentiated into polarized acini between days 5 and 7.
Gene expression signature in organized and growth-arrested mammary acini predicts good outcome in breast cancer.
Sex, Specimen part, Cell line, Time
View SamplesMouse lung cancers were generated using the KrasLA model, in which a latent mutated Kras2 allele (resulting in the amino acid substitution G12D) is sporadically activated through spontaneous homologous recombination. These mice develop lung adenomas with full penetrance; over time, the tumors acquire morphologic characteristics reminiscent of those of human adenocarcinoma, such as nuclear atypia and a high mitotic index.
An oncogenic KRAS2 expression signature identified by cross-species gene-expression analysis.
Specimen part
View SamplesLandmark events occur in a coordinated manner during preimplantation development of the mammalian embryo, yet the regulatory network that orchestrates these events remains largely unknown.
An Oct4-Sall4-Nanog network controls developmental progression in the pre-implantation mouse embryo.
No sample metadata fields
View SamplesStudies of the Xenopus organizer have laid the foundation for our understanding of the conserved signaling pathways that pattern vertebrate embryos during gastrulation. Here, we use this wealth of knowledge as leverage in the design and analysis of a genomic visualization of organizer-related gene transcription. Using ectopic expression of the two major activities of the organizer, BMP and Wnt inhibition, as well as endogenous tissues, we generate a focused set of samples that represent different aspects of organizer signaling. The genomic expression values of each sample are then measured with oligonucleotide arrays. From this data, genes regulated by organizer signaling are selected and then clustered by their patterns of regulation. A new GO biological process annotation of the Xenopus genome allows us to rapidly identify clusters that are highly enriched for known gastrula patterning genes. Within these clusters, we can predict the expression patterns of unknown genes with remarkable accuracy, leading to the discovery of new organizer-related gastrula stage expression patterns for 19 genes. Moreover, the patterns of gene response observed within these clusters allow us to parse apart the contributions of BMP and Wnt inhibition in organizer function. We find that the majority of gastrula patterning genes respond transcriptionally to these activities according to only a few stereotyped patterns, allowing us to describe suites of genes that are likely to share similar regulatory mechanisms. These suites of genes demonstrate a mechanism where BMP inhibition initiates the organizer program before gastrulation, and Wnt inhibition maintains and drives the organizer program during gastrulation.
Genomic analysis of Xenopus organizer function.
Specimen part
View SamplesThis SuperSeries is composed of the SubSeries listed below.
High-throughput screening of tyrosine kinase inhibitor cardiotoxicity with human induced pluripotent stem cells.
Specimen part, Cell line, Treatment, Subject
View SamplesProspectively isolated and characerized skeletal progenitor lineages
Identification and specification of the mouse skeletal stem cell.
Specimen part
View SamplesProspectively isolated and characerized skeletal progenitor lineages
Identification and specification of the mouse skeletal stem cell.
Specimen part
View SamplesThe retinoblastoma cell cycle regulator pRb and the two related proteins p107 and p130 are thought to suppress cancer development both by inhibiting the G1/S transition of the cell cycle in response to growth-arrest signals and by promoting cellular differentiation. Here, we investigated the phenotype of Rb family triple knock-out (TKO) embryonic stem cells as they differentiate in vivo and in culture. Confirming the central role of the Rb gene family in cell cycle progression, TKO mouse embryos did not survive past mid-gestation and differentiating TKO cells displayed increased proliferation and cell death. However, patterning and cell fate determination were largely unaffected in these TKO embryos. Furthermore, a number of TKO cells, including in the neural lineage, were able to exit the cell cycle in G1 and terminally differentiate. This ability of Rb family TKO cells to undergo cell cycle arrest was associated with the repression of target genes for the E2F6 transcription factor, uncovering a pRb-independent control of the G1/S transition of the cell cycle. These results show that the Rb gene family is required for proper embryonic development but is not absolutely essential to induce G1 arrest and differentiation in certain lineages.
G1 arrest and differentiation can occur independently of Rb family function.
No sample metadata fields
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