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GSE68110
Rattus norvegicus
418 Downloadable Samples
Affymetrix Rat Expression 230A Array (rae230a)
Description
The carcinogenic potential of chemicals is currently evaluated with rodent life-time bioassays, which are time consuming, and expensive with respect to cost, number of animals and amount of compound required. Since the results of these 2-year bioassays are not known until quite late during development of new chemical entities, and since the short-term test battery to test for genotoxicity, a characteristic of genotoxic carcinogens, is hampered by low specificity, the identification of early biomarkers for carcinogenicity would be a big step forward. Using gene expression profiles from the livers of rats treated up to 14 days with genotoxic and non-genotoxic carcinogens we previously identified characteristic gene expression profiles for these two groups of carcinogens. We have now added expression profiles from further hepatocarcinogens and from non-carcinogens the latter serving as control profiles. We used these profiles to extract biomarkers discriminating genotoxic from non-genotoxic carcinogens and to calculate classifiers based on the support vector machine (SVM) algorithm. These classifiers then predicted a set of independent validation compound profiles with up to 88% accuracy, depending on the marker gene set. We would like to present this study as proof of the concept that a classification of carcinogens based on short-term studies may be feasible.
Publication Title
Cross-platform toxicogenomics for the prediction of non-genotoxic hepatocarcinogenesis in rat.
Sample Metadata Fields
Specimen part
View Samples- Rattus norvegicus
- 63 Downloadable Samples
Affymetrix Rat Expression 230A Array (rae230a)
Description
This SuperSeries is composed of the SubSeries listed below.
Publication Title
Cross-platform toxicogenomics for the prediction of non-genotoxic hepatocarcinogenesis in rat.
Sample Metadata Fields
Sex, Specimen part
View Samples- Rattus norvegicus
- 63 Downloadable Samples
- Affymetrix Rat Expression 230A Array (rae230a)
Description
In this study we performed microarray-based molecular profiling of liver samples from Wistar rats exposed to genotoxic carcinogens (GC), nongenotoxic carcinogens (NGC) or non-hepatocarcinogens (NC) for up to 14 days. In contrast to previous toxicogenomics studies aimed at the inference of molecular signatures for assessing the potential and mode of compound carcinogenicity, we considered multi-level omics data. Besides evaluating the predictive power of signatures observed on individual biological levels, such as mRNA, miRNA and protein expression, we also introduced novel feature representations which capture putative molecular interactions or pathway alterations by integrating expression profiles across platforms interrogating different biological levels.
Publication Title
Cross-platform toxicogenomics for the prediction of non-genotoxic hepatocarcinogenesis in rat.
Sample Metadata Fields
Sex, Specimen part
View Samples- Mus musculus
- 16 Downloadable Samples
- Affymetrix Mouse Genome 430 2.0 Array (mouse4302)
Description
Embryonic mouse brain development involves a sequential differentiation of multipotent progenitor cells into neurons and glia. Using microarrays and large 2-D electrophoresis, we investigated the transcriptome and proteome of mouse brains at embryonic days 9.5, 11.5 and 13.5. During this developmental period, neural progenitor cells shift from proliferation to neuronal differentiation. As expected, we detected numerous expression changes between the time points investigated but interestingly, the rate of alteration was about 10% to 13% of all proteins and mRNAs during every two days of development. Furthermore, up- and downregulation was balanced. This was confirmed for two additional stages of development, embryonic day 16 and 18. We hypothesize that during embryonic development, the rate of protein expression alteration is rather constant due to a limitation of cellular resources such as energy, space and free water. The similar complexity found at the transcriptome and proteome level at all stages suggests, that changes in relative concentration of gene products rather than an increased number of gene products dominate throughout cellular differentiation. We found that metabolism and cell cycle related gene products were downregulated in expression when precursor cells switched from proliferation to neuronal differentiation (day 9.5 to 11.5), whereas neuron specific gene products were upregulated. A detailed analysis revealed their implication in differentiation related processes such as rearrangement of the actin cytoskeleton as well as Notch and Wnt signaling pathways.
Publication Title
Transcriptome and proteome analysis of early embryonic mouse brain development.
Sample Metadata Fields
No sample metadata fields
View Samples- Xenopus laevis
- 3 Downloadable Samples
- Affymetrix Xenopus laevis Genome 2.0 Array (xlaevis2)
Description
Pregnane X receptor (PXR) is generally considered the most important sensor of natural and anthropogenic xenobiotics in vertebrates. In Xenopus, however, PXR plays a role in neural development and it is irresponsive to xenobiotics. We report a first broad-spectrum amphibian xenobiotic receptor, which is an ortholog of the mammalian constitutive androstane receptor (CAR). The low basal activity and pronounced responsiveness to activators such as drugs and steroids displayed by the Xenopus CAR resemble PXR, which both trace back to a common ancestor early in the divergence of land vertebrates. The constitutive activity of CAR emerged first in Sauropsida (reptiles and birds) and it is common to all fully terrestrial land vertebrates (Amniota). This activity can be mimicked by humanizing just two amino acids of the Xenopus CAR. These results demonstrate a remarkable plasticity of CAR which enabled its employment as Xenopus xenosensors. They open way to toxicogenomic and bioaugmentation studies in amphibians, a critically endangered taxon of land vertebrates. Taken together, we provide evidence for a much earlier origin of CAR, for its conservation in tetrapods which exceeds that of PXR, and for its remarkable functional plasticity which enabled its role as a PXR-like xenosensor in Amphibia.
Publication Title
Evolutionary history and functional characterization of the amphibian xenosensor CAR.
Sample Metadata Fields
Sex, Specimen part, Treatment
View Samples- Homo sapiens
- 78 Downloadable Samples
Illumina HiSeq 2500, Illumina HiSeq 3000, NextSeq 500
Description
Interrogation and control of cellular fate and function using optogenetics is providing revolutionary insights into biology. Optogenetic control of cells is achieved by coupling genetically encoded photoreceptors to cellular effectors and enables unprecedented spatiotemporal control of signaling processes. Here, a fast and reversibly switchable photoreceptor is used to tune the mechanical properties of polymer materials in a fully reversible, wavelength-specific, and dose- and space-controlled manner. By integrating engineered cyanobacterial phytochrome 1 into a polyethylene glycol matrix, hydrogel materials responsive to light in the cell-compatible red/far-red spectrum are synthesized. These materials are applied to study in human mesenchymal stem cells how different mechano-signaling pathways respond to changing mechanical environments, and to control the migration of primary immune cells in 3D. This optogenetics-inspired matrix allows addressing fundamental questions of how cells react to dynamic mechanical environments. Further, remote control of such matrices could create new opportunities for tissue engineering or provide a basis for optically stimulated drug depots. Overall design: Analysis of global gene expression changes due to differences in the mechanical properties of the phytochrome-based hydrogels
Publication Title
Phytochrome-Based Extracellular Matrix with Reversibly Tunable Mechanical Properties.
Sample Metadata Fields
Subject
View Samples