Microarray expression profiling has become a valuable tool in the evaluation of the genetic consequences of metabolic disease. Although 3-biased gene expression microarray platforms were the first generation to have widespread availability, newer platforms are gradually emerging that have more up-to-date content and/or higher cost efficiency. Deciphering the relative strengths and weaknesses of these various platforms for metabolic pathway level analyses can be daunting. We sought to determine the practical strengths and weaknesses of four leading commercially-available expression array platforms relative to biologic investigations, as well as assess the feasibility of cross-platform data integration for purposes of biochemical pathway analyses. METHODS: Liver RNA from B6.Alb/cre,Pdss2loxP/loxP mice having primary Coenzyme Q deficiency was extracted either at baseline or following treatment with an antioxidant/antihyperlipidemic agent, probucol. Target RNA samples were prepared and hybridized to Affymetrix 430 2.0, Affymetrix Gene 1.0 ST, Affymetrix Exon 1.0 ST, and Illumina Mouse WG-6 expression arrays. Probes on all platforms were re-mapped to coding sequences in the current version of the mouse genome. Data processing and statistical analysis were performed by R/Bioconductor functions, and pathway analyses were carried out by KEGG Atlas and GSEA. RESULTS: Expression measurements were generally consistent across platforms. However, intensive probe-level comparison suggested that differences in probe locations were a major source of inter-platform variance. In addition, genes expressed at low or intermediate levels had lower inter-platform reproducibility than highly expressed genes. All platforms showed similar patterns of differential expression between sample groups, with steroid biosynthesis consistently identified as the most down-regulated metabolic pathway by probucol treatment. CONCLUSIONS: This work offers a timely guide for metabolic disease investigators to enable informed end-user decisions regarding choice of expression microarray platform best-suited to specific research project goals. Successful cross-platform integration of biochemical pathway expression data is also demonstrated, especially for well-annotated and highly-expressed genes. However, integration of gene-level expression data is limited by individual platform probe design and the expression level of target genes. Cross-platform analyses of biochemical pathway data will require additional data processing and novel computational bioinformatics tools to address unique statistical challenges.
Cross-platform expression microarray performance in a mouse model of mitochondrial disease therapy.
Sex, Age, Specimen part, Treatment
View SamplesHuman medulloblastoma (MB) can be segregated into four major categories based on gene expression patterns: Hedgehog (HH) subtype, Wnt subtype, Group 3, and Group 4. However, they all exhibit strikingly different gene expression profiles from Atypical Teratoid/Rhabdoid Tumor (AT/RT). We re-analyzed published gene expression microarray dataset of pediatric brain tumors to identify a gene expression profile that clearly distinguished human AT/RT from human MB. We used this profile, choosing only genes that have clear murine orthologs, to compare tumors from Snf5F/Fp53L/LGFAP-Cre mice (in C57Bl/6 strain background) with MB from Ptc1+/- mice (in mixed C57Bl/6 and 129Sv strain background). Snf5F/Fp53L/LGFAP-Cre tumors are clearly very different from mouse MB and the markers that distinguish human AT/RT from human MB also distinguish the mouse tumors.
Generation of a mouse model of atypical teratoid/rhabdoid tumor of the central nervous system through combined deletion of Snf5 and p53.
No sample metadata fields
View SamplesThis SuperSeries is composed of the SubSeries listed below.
Cyclical expression of the Notch/Wnt regulator Nrarp requires modulation by Dll3 in somitogenesis.
Age, Specimen part
View SamplesThe transcriptional activating and repressive functions performed by Trithorax and Polycomb group complexes, respectively, are critical for to maintain cellular fates in ontogeny and in cancer. Here we report that leukemias initiated by a Trithorax-related oncogene, MLL-AF9, depend upon the Polycomb Repressive Complex 2 (PRC2) to sustain a transformed cellular state. RNAi mediated suppression of PRC2 subunits is sufficient to inhibit proliferation of MLL-AF9 leukemias, with little impact on growth of non-transformed cells. This requirement is partly due to PRC2-mediated transcriptional repression of several anti-self-renewal regulators, including Cdkn2a. These results suggest that, unlike the classical antagonism generally observed between Polycomb and Trithorax group proteins during development, the activities of these two pathways can cooperate to promote myeloid neoplasia.
The Polycomb complex PRC2 supports aberrant self-renewal in a mouse model of MLL-AF9;Nras(G12D) acute myeloid leukemia.
No sample metadata fields
View SamplesCancer stem cells (CSCs) are plastic in nature, a characteristic that hampers cancer therapeutics. Neuroblastoma (NB) is a pediatric tumor of neural crest origin, and half of the cases are highly aggressive. By treating NB cell lines (SKNAS, SKNBE(2)C, CHP134, SY5Y) with epigenetic modifiers for a short time followed by sphere-forming culture conditions, we have established stem cell-like NB cells that are phenotypically stable for over a year. These cells are characterized by their high expression of stemness factors, stem cell markers, and open chromatin structure. We referred to these cells as induced CSC (iCSC). SKNAS iCSC and SKNBE(2)C iCSC clones (as few as 100 cells) injected subcutaneously into SCID/Beige mice formed tumors, and in one case, SKNBE(2)C iCSC metastasized to the adrenal gland, suggesting their increased metastatic potential. SKNAS iCSC xenografts showed the histologic appearance of totally undifferentiated large-cell NBs (LCNs), the most aggressive and deadly form of NB in humans. Immunohistochemical analyses showed that SKNAS iCSC xenografts expressed high levels of the stem cell marker CXCR4, while the SKNAS monolayer cell xenografts did not. The patterns of CXCR4 and MYC expression in SKNAS iCSC xenografts resembled those in the LCNs. The xenografts established from the NB iCSCs shared two common features: the LCN phenotype and high-level MYC/MYCN expression. These observations suggest that NB cells with large and vesicular nuclei, representing their open chromatin structure, are indicative of stem cell-like tumor cells, and that epigenetic changes may have contributed to the development of these most malignant NB cells.
Transient treatment with epigenetic modifiers yields stable neuroblastoma stem cells resembling aggressive large-cell neuroblastomas.
No sample metadata fields
View SamplesNovel taste memories, critical for animal survival, are consolidated to form long term memories which are dependent on translation regulation in the gustatory cortex
Fluid consumption and taste novelty determines transcription temporal dynamics in the gustatory cortex.
Sex, Age, Specimen part, Treatment, Time
View SamplesThis SuperSeries is composed of the SubSeries listed below.
Identification of oscillatory genes in somitogenesis from functional genomic analysis of a human mesenchymal stem cell model.
Specimen part
View SamplesDuring somitogenesis, oscillatory expression of genes in the notch and wnt signaling pathways plays a key role in regulating segmentation. These oscillations in expression levels are elements of a species-specific developmental mechanism. To date, the periodicity and components of the human clock remain unstudied. Here we show that a human mesenchymal stem/stromal cell (MSC) model can be induced to display oscillatory gene expression. We observed that the known cycling gene HES1 oscillated with a 5 hour period, consistent with available data on the rate of somitogenesis in humans. We also observed cycling of Hes1 expression in mouse C2C12 myoblasts with a period of 2 hours, consistent with previous in vitro and embryonic studies. Furthermore, we used microarray and quantitative PCR (Q-PCR) analysis to identify additional genes that display oscillatory expression both in vitro and in mouse embryos. We confirmed oscillatory expression of the notch pathway gene Maml3 and the wnt pathway gene Nkd2 by whole mount in situ hybridization analysis and Q-PCR. Expression patterns of these genes were disrupted in Wnt3atm1Amc mutants but not in Dll3pu mutants. Our results demonstrate that human and mouse in vitro models can recapitulate oscillatory expression observed in embryo and that a number of genes in multiple developmental pathways display dynamic expression in vitro.
Identification of oscillatory genes in somitogenesis from functional genomic analysis of a human mesenchymal stem cell model.
No sample metadata fields
View SamplesPhenotypic heterogeneity has been observed among mesenchymal stem/stromal cell (MSC) populations, but specific genes associated with this variability have not been defined. To study this question, we analyzed two distinct MSC populations isolated from the same umbilical cord blood (UCB) sample. These populations (UCB1 and UCB2) are from a single donor, minimizing differences contributed by genetic background. We characterized these UCB-MSCs for cell morphology, growth kinetics, immunophenotype and differentiation potential. UCB1 displayed rapid growth kinetics, higher population doublings, and increased adipogenic lineage differentiation compared to UCB2. To identify the MSC-specific and developmental genes associated with these phenotypic differences, we performed expression analysis using Affymetrix HG-U133 microarrays and compared them to bone marrow (BM) MSCs. First, hepatocyte growth factor (HGF) and stromal derived factor 1 (SDF1/CXCL12) were up -regulated in UCB1 cells, potentially contributing to the higher growth kinetics observed in this circulating cell population. Second, we observed that peroxisome proliferation activated receptor gamma (PPARG), a marker for adipogenic differentiation, was significantly increased in undifferentiated UCB1 cells. Moreover, significant expression of gene markers of blastocyst and gatrulation embryonic stages were detected in UCB1 and UCB2 cells, as were selected markers of early hematopoiesis, chondrogenesis, and cardiac differentiation. Comparison of UCB1, UCB2, and BM by microarray analysis clearly demonstrated clusters of developmental genes that displayed significant differences among these cells. Quantitative PCR analysis of selected genes validated the microarray results. Comparison of different UCB-derived adherent cells from a single donor has identified gene profiles potentially useful for therapeutic evaluation of MSC populations.
Identification of cord blood-derived mesenchymal stem/stromal cell populations with distinct growth kinetics, differentiation potentials, and gene expression profiles.
Specimen part
View SamplesDuring somitogenesis, oscillatory expression of genes in the notch and wnt signaling pathways plays a key role in regulating segmentation. These oscillations in expression levels are elements of a species-specific developmental mechanism. To date, the periodicity and components of the human clock remain unstudied. Here we show that a human mesenchymal stem/stromal cell (MSC) model can be induced to display oscillatory gene expression. We observed that the known cycling gene HES1 oscillated with a 5 hour period, consistent with available data on the rate of somitogenesis in humans. We also observed cycling of Hes1 expression in mouse C2C12 myoblasts with a period of 2 hours, consistent with previous in vitro and embryonic studies. Furthermore, we used microarray and quantitative PCR (Q-PCR) analysis to identify additional genes that display oscillatory expression both in vitro and in mouse embryos. We confirmed oscillatory expression of the notch pathway gene Maml3 and the wnt pathway gene Nkd2 by whole mount in situ hybridization analysis and Q-PCR. Expression patterns of these genes were disrupted in Wnt3atm1Amc mutants but not in Dll3pu mutants. Our results demonstrate that human and mouse in vitro models can recapitulate oscillatory expression observed in embryo and that a number of genes in multiple developmental pathways display dynamic expression in vitro.
Identification of oscillatory genes in somitogenesis from functional genomic analysis of a human mesenchymal stem cell model.
Specimen part
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