The mature CNS contains PDGFRA+ oligodendrocyte progenitor cells (OPC) which may remain quiescent, proliferate, or differentiate into oligodendrocytes. In human gliomas, rapidly proliferating Olig2+ cells resembling OPCs are frequently observed. We sought to identify, in vivo, candidate pathways uniquely required for OPC differentiation or quiescence. Using the bacTRAP methodology, we generated and analyzed mouse lines for translational profiling the major cells types (including OPCs), in the normal mouse brain. We then profiled oligodendoglial (Olig2+) cells from a mouse model of Pdgf-driven glioma. This analysis confirmed that Olig2+ tumor cells are most similar to OPCs, yet, it identified differences in key progenitor genes - candidates for promotion of differentiation or quiescence.
Candidate pathways for promoting differentiation or quiescence of oligodendrocyte progenitor-like cells in glioma.
Specimen part
View SamplesComparison of polysomal profiles of murine adult olig2 cortical progenitors, murine tumor olig2 cells derived from hPDGF-B-driven glioblastomas, and murine olig2 proliferative recruited glioma cells contributing to the tumor mass but not derived from the cell of origin
Recruited cells can become transformed and overtake PDGF-induced murine gliomas in vivo during tumor progression.
Specimen part
View SamplesHere we characterize and optimize both systems to increase their utility for preclinical studies. We show that TH-MYCN mice develop tumors in the paraspinal ganglia, but not in the adrenal, with cellular and gene expression patterns similar to human NB. In addition, we present a new ultrasound guided, non-invasive orthotopic xenograft method. This injection technique is rapid, provides accurate targeting of the injected cells and leads to efficient engraftment. We also demonstrate that tumors can be detected, monitored and quantified prior to visualization using ultrasound, MRI and bioluminescence. Finally we develop and test a standard of care chemotherapy regimen. This protocol, which is based on current treatments for neuroblastoma, provides a baseline for comparison of new therapeutic agents.
Preclinical models for neuroblastoma: establishing a baseline for treatment.
Specimen part
View SamplesGlioblastoma (GBM) is a highly lethal brain tumor presenting as one of two subtypes with distinct clinical histories and molecular profiles. The primary GBM subtype presents acutely as high-grade disease that typically harbors EGFR, PTEN and Ink4a/Arf mutations, and the secondary GBM subtype evolves from the slow progression of low-grade disease that classically possesses PDGF and p53 events1. Here, we show that concomitant CNS-specific deletion of p53 and Pten in the mouse CNS generates a penetrant acute-onset high-grade malignant glioma phenotype with striking clinical, pathological and molecular resemblance to primary GBM in humans. This genetic observation prompted p53 and PTEN mutational analysis in human primary GBM, demonstrating unexpectedly frequent inactivating mutations of p53 as well the expected PTEN mutations. Integrated transcriptomic profling, in silico promoter analysis and functional studies of murine neural stem cells (NSCs) established that dual, but not singular, inactivation of p53 and Pten promotes an undifferentiated state with high renewal potential and drives elevated c-Myc levels and its associated signature. Functional studies validated increased c-Myc activity as a potent contributor to the impaired differentiation and enhanced renewal of p53-Pten null NSCs as well as tumor neurospheres (TNSs) derived from this model. c-Myc also serves to maintain robust tumorigenic potential of p53-Pten null TNSs. These murine modeling studies, together with confirmatory transcriptomic/promoter studies in human primary GBM, validate a pathogenetic role of a common tumor suppressor mutation profile in human primary GBM and establish c-Myc as a key target for cooperative actions of p53 and Pten in the regulation of normal and malignant stem/progenitor cell differentiation, self-renewal and tumorigenic potential.
p53 and Pten control neural and glioma stem/progenitor cell renewal and differentiation.
No sample metadata fields
View SamplesIdentification of all genes expressed by mouse olfactory sensory neurons; genes expressed in mature neurons, immature neurons, or both were distinguished. Independent validation of enrichment ratio values supported by statistical assessment of error rates was used to build a database of statistical probabilities of the expression of all mRNAs detected in mature neurons, immature neurons, both types of neurons (shared), and the residual population of all other cell types.
Genomics of mature and immature olfactory sensory neurons.
Sex, Specimen part
View SamplesTranscriptional profiling of the zebrafish embryonic host response to a systemic bacterial infection with Salmonella typhimurium (strain SL1027); comparison between traf6 knock-down and control morpholino treated embryos. Overall design: All infection experiments were performed using mixed egg clutches of ABxTL strain zebrafish. Embryos injected with traf6 morpholino or a 5bp mismatch control morpholino were staged at 27 hours post fertilization (hpf) by morphological criteria and approximately 250 cfu of DsRed expressing Salmonella bacteria were injected into the caudal vein close to the urogenital opening. As a control an equal volume of PBS was likewise injected. Pools of 20-40 infected and control embryos were collected 8 hours post infection (hpi). The whole procedure was preformed in triplicate on separate days. Total RNA of the biological triplicates was pooled using equal amounts of RNA prior to RNAseq library preparation.
Transcriptome analysis of Traf6 function in the innate immune response of zebrafish embryos.
No sample metadata fields
View SamplesThis SuperSeries is composed of the SubSeries listed below.
Exploiting microRNA and mRNA profiles generated in vitro from carcinogen-exposed primary mouse hepatocytes for predicting in vivo genotoxicity and carcinogenicity.
Specimen part, Compound
View SamplesThe well-defined battery of in vitro systems applied within chemical cancer risk assessment is often characterised by a high false-positive rate, thus repeatedly failing to correctly predict the in vivo genotoxic and carcinogenic properties of test compounds. Toxicogenomics, i.e. mRNA-profiling, has been proven successful in improving the prediction of genotoxicity in vivo and the understanding of underlying mechanisms. Recently, microRNAs have been discovered as post-transcriptional regulators of mRNAs. It is thus hypothesised that using microRNA response-patterns may further improve current prediction methods. This study aimed at predicting genotoxicity and non-genotoxic carcinogenicity in vivo, by comparing microRNA- and mRNA-based profiles, using a frequently applied in vitro liver model and exposing this to a range of well-chosen prototypical carcinogens. Primary mouse hepatocytes (PMH) were treated for 24 and 48h with 21 chemical compounds [genotoxins (GTX) vs. non-genotoxins (NGTX) and non-genotoxic carcinogens (NGTX-C) versus non-carcinogens (NC)]. MicroRNA and mRNA expression changes were analysed by means of Exiqon and Affymetrix microarray-platforms, respectively. Classification was performed by using Prediction Analysis for Microarrays (PAM). Compounds were randomly assigned to training and validation sets (repeated 10 times). Before prediction analysis, pre-selection of microRNAs and mRNAs was performed by using a leave-one-out t-test. No microRNAs could be identified that accurately predicted genotoxicity or non-genotoxic carcinogenicity in vivo. However, mRNAs could be detected which appeared reliable in predicting genotoxicity in vivo after 24h (7 genes) and 48h (2 genes) of exposure (accuracy: 90% and 93%, sensitivity: 65% and 75%, specificity: 100% and 100%). Tributylinoxide and para-Cresidine were misclassified. Also, mRNAs were identified capable of classifying NGTX-C after 24h (5 genes) as well as after 48h (3 genes) of treatment (accuracy: 78% and 88%, sensitivity: 83% and 83%, specificity: 75% and 93%). Wy-14,643, phenobarbital and ampicillin trihydrate were misclassified. We conclude that genotoxicity and non-genotoxic carcinogenicity probably cannot be accurately predicted based on microRNA profiles. Overall, transcript-based prediction analyses appeared to clearly outperform microRNA-based analyses.
Exploiting microRNA and mRNA profiles generated in vitro from carcinogen-exposed primary mouse hepatocytes for predicting in vivo genotoxicity and carcinogenicity.
Specimen part, Compound
View SamplesThis SuperSeries is composed of the SubSeries listed below.
Evaluating microRNA profiles reveals discriminative responses following genotoxic or non-genotoxic carcinogen exposure in primary mouse hepatocytes.
Specimen part, Compound
View SamplesThe study investigated differential gene expression in primary mouse hepatocyte mRNA following 24 and 48 hours of exposure to aflatoxin B1, cisplatin, benzo(a)pyrene, 2,3,7,8-tetrachloordibenzo-p-dioxine, cyclosporin A or Wy-14,643 or their responsive solvent. Three (four for Wy-14,643) biological replicates per compound/solvent.
Evaluating microRNA profiles reveals discriminative responses following genotoxic or non-genotoxic carcinogen exposure in primary mouse hepatocytes.
Specimen part, Compound
View Samples