Down syndrome (trisomy 21) is the most common genetic cause of intellectual disability, but the precise molecular mechanisms underlying impaired cognition remain unclear. Elucidation of these mechanisms has been hindered by the lack of a model system that contains full trisomy of chromosome 21 (Ts21) in a human genome that enables normal gene regulation. To overcome this limitation,we created Ts21-induced pluripotent stem cells (iPSCs) from two sets of Ts21 human fibroblasts. One of the fibroblast lines had low level mosaicism for Ts21 and yielded Ts21 iPSCs and an isogenic control that is disomic for human chromosome 21 (HSA21). Differentiation of all Ts21 iPSCs yielded similar numbers of neurons expressingmarkers characteristic of dorsal forebrain neurons that were functionally similar to controls. Expression profiling of Ts21 iPSCs and their neuronal derivatives revealed changes in HSA21 genes consistent with the presence of 50% more genetic material as well as changes in non- HSA21 genes that suggested compensatory responses to oxidative stress. Ts21 neurons displayed reduced synaptic activity, affecting excitatory and inhibitory synapses equally. Thus, Ts21 iPSCs and neurons display unique developmental defects that are consistent with cognitive deficits in individuals with Down syndrome and may enable discovery of the underlying causes of and treatments for this disorder.
Deficits in human trisomy 21 iPSCs and neurons.
Specimen part, Time
View SamplesThe absence of the Rb tumor suppressor gene changes levels/activities of transcription factors (e.g., E2F and p53) which alter gene expression patterns, related to cell cycle control and cellular response to DNA damage. Cisplatin is a genotoxic chemotherapeutic agent and wildtype or Rb null cells have different sensitivities to cisplatin-induced cytotoxicity.
Elevated poly-(ADP-ribose)-polymerase activity sensitizes retinoblastoma-deficient cells to DNA damage-induced necrosis.
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View SamplesFetal spleens were collected at days 82 and 97 of gestation following maternal infection with BVDV on day 75 of gestation.
Attenuated lymphocyte activation leads to the development of immunotolerance in bovine fetuses persistently infected with bovine viral diarrhea virus†.
Sex, Specimen part
View SamplesMicroRNAs (miRNA) are small, non-coding RNAs mediating post-transcriptional regulation of gene expression. miRNAs have recently been implicated in hippocampus-dependent functions such as learning and memory, although the roles of individual miRNAs in these processes remain largely unknown. Here, we achieved stable inhibition using AAV-delivered miRNA sponges of individual, highly expressed and brain-enriched miRNAs; miR-124, miR-9 and miR-34, in hippocampal neurons. Molecular and cognitive studies revealed a role for miR-124 in learning and memory. Inhibition of miR-124 resulted in an enhanced spatial learning and working memory capacity, potentially through altered levels of genes linked to synaptic plasticity and neuronal transmission. In contrast, inhibition of miR-9 or miR-34 led to a decreased capacity of spatial learning and of reference memory, respectively. On a molecular level, miR-9 inhibition resulted in altered expression of genes related to cell adhesion, endocytosis and cell death, while miR-34 inhibition caused transcriptome changes linked to neuroactive ligand-receptor transduction and cell communication. In summary, this study establishes distinct roles for individual miRNAs in hippocampal function. Overall design: Three RNA samples containing bilateral entire hippocampi from three different mice, per group. Group 1 were injected with vector containing GFP and a miR34sp/miR9sp and the other group were subjected to a vector expressing GFP only.
Distinct cognitive effects and underlying transcriptome changes upon inhibition of individual miRNAs in hippocampal neurons.
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View SamplesAffymetric arrays were performed on thyroid samples collected from GEMMs: normal thyroid, TPO-Cre/LSL-Braf (PTC), TPO-Cre/tetO-BRAF/LSL-rtTAiresGFP/p53-flox (ATC) and TPO-Cre/tetO-BRAF/LSL-rtTAiresGFP/p53-flox (recurrent tumors)
Hgf/Met activation mediates resistance to BRAF inhibition in murine anaplastic thyroid cancers.
Specimen part
View SamplesWe characterized gene expression changes in the developing mouse liver at gestational days (GD) 11.5, 12.5, 13.5, 14.5, 16.5, and 19.5 and in the neonate (postnatal day (PND) 7 and 30) using full-genome microarrays and compared these changes to that in the adult liver. The fetal liver, and to a lesser extent the neonatal liver, exhibited dramatic differences in gene expression compared to adults. Canonical pathway analysis of the fetal liver signature demonstrated increases in functions important in cell replication and DNA fidelity whereas most metabolic pathways of intermediary metabolism were suppressed. Comparison of the dataset to a number of previously published datasets revealed 1) a striking similarity between the fetal liver and that of the pancreas in both mice and humans, 2) a nucleated erythrocyte signature in the fetus and 3) suppression of most xenobiotic metabolism genes throughout development, except a number of transporters associated with expression in hematopoietic cells.
Transcriptional ontogeny of the developing liver.
Specimen part
View SamplesWe established a neuron-specific Argonaute2:GFP-RNA immunoprecipitation followed by high throughput sequencing (AGO2-RIP-seq) to analyse the regulatory role of miRNAs in mouse hippocampal neurons. Using this technique, we identified more than two thousand miRNA target genes in hippocampal neurons, regulating essential neuronal features such as axon guidance and transcription. Furthermore, we found that stable inhibition of the highly expressed miR-124 in hippocampal neurons led to significant changes in the AGO2 binding of target mRNAs, resulting in subsequent upregulation of numerous miRNA target genes. Our data suggest that target redundancies are common among microRNA families. Together, these findings greatly enhance our understanding of the mechanisms and dynamics through which miRNAs regulate their target genes in neurons. Overall design: Analysis of the miRNA targetome in hippocampal neurons after inhibition of 2 different miRNAs. AAV5 injections into the hippocampus of adult C57BL/6 mice producing either of the following under a synapsin promoter: GFP only (Samples beginning with ''GFP124…'' or ''GFP125…''), GFP-miR124sp (Samples beginning with ''miR124…''), GFP-miR125sp (Samples beginning with ''miR125…''), GFP-AGO2-miR292sponge (samples ending with ''…292''), GFP-AGO2-miR124sponge (samples ending with ''…124''), GFP-AGO2-miR125sponge (samples ending with ''…125''). All other samples were sham-injected.
Identification of the miRNA targetome in hippocampal neurons using RIP-seq.
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View SamplesPurpose: To identify genes that are transcriptionally controlled by Notch signaling during zebrafish lateral line proneuromast formation. Methods: We isolated primordium cells from dissected tails of 36 hpf Tg((cldnB:GFP);Tg(cldnB:gal4) x Tg(UAS:nicd)) and sibling Tg((cldnB:GFP);Tg(cldnB:gal4)) embryos by FACS and performed RNASeq analysis. Results: Using an optimized data analysis workflow, we mapped about 26 million sequence reads per sample to the zebrafish genome (build danRer10) and identified 32,105 transcripts in the dissociated tails of WT and NICD zebrafish with TopHat workflow. Approximately 2% of the transcripts showed differential expression between the WT and NICD tails, with a fold change =0.5 and p value <0.01. Conclusion: RNASeq analyses revealed that Notch signaling cell-autonomously induces apical constriction and cell adhesion. Overall design: Zebrafish lateral line mRNA profiles of 36 hours wild type (WT) and NICD embryos were generated in triplicate, using HiSeq 2500 (Illumina).
Proliferation-independent regulation of organ size by Fgf/Notch signaling.
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View SamplesJQ1 is a small-molecule (BET family) bromodomain inhibitor that causes a contraceptive effect in mice by blocking spermatogenesis and reducing sperm motility.
Small-molecule inhibition of BRDT for male contraception.
Sex, Specimen part
View SamplesThis SuperSeries is composed of the SubSeries listed below.
Gene expression profiling-based identification of molecular subtypes in stage IV melanomas with different clinical outcome.
Sex, Specimen part
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