Malformations of the cardiovascular system are the most common type of birth defect in humans, affecting predominantly the formation of valves and septa. During heart valve and septa formation, cells from the atrio-ventricular canal (AVC) and outflow tract (OFT) regions of the heart undergo an epithelial-to-mesenchymal transformation (EMT) and invade the underlying extracellular matrix to give rise to endocardial cushions. Subsequent maturation of newly formed mesenchyme cells leads to thin stress-resistant leaflets. TWIST1 is a basic helix-loop-helix transcription factor expressed in newly formed mesenchyme cells of the AVC and OFT that has been shown to play roles in cell survival, cell proliferation and differentiation. However, the role and downstream targets of TWIST1 during heart valve formation remain unclear. To identify genes important for heart valve development downstream of Twist1 we performed global gene expression profiling of AVC, OFT, atria and ventricles of the embryonic day 10.5 mouse heart by tag-sequencing (Tag-seq). Using this resource we identified a novel set of 1246 genes, including 201 regulators of transcription, enriched in the valve forming regions of the heart. We compared these genes to a Tag-seq library from the Twist1 null developing valves revealing significant gene expression changes. These changes were consistent with a role of TWIST1 in controlling differentiation of mesenchymal cells following their transformation from endothelium in the mouse. To study the role of TWIST1 at the DNA level we performed chromatin immunoprecipitation and identified novel direct targets of TWIST1 in the developing heart valves. Our findings are consistent with a role for TWIST1 in the differentiation of AVC mesenchyme post-EMT in the mouse, and suggest that TWIST1 exerts its function by direct DNA binding to activate valve specific gene expression. Overall design: Profiled the AVC, OFT, atria and ventricles of the embryonic day 10.5 mouse heart by tag-sequencing (Tag-seq) (no replicates). We also produced a Tag-seq library from Twist1 null developing valves to reveal the gene expression changes associated with loss of this gene.
Twist1 transcriptional targets in the developing atrio-ventricular canal of the mouse.
Specimen part, Cell line, Subject
View SamplesDNA methylation and histone H3 lysine 9 trimethylation (H3K9me3) play important roles in silencing of genes and retroelements. However, a comprehensive comparison of genes and repetitive elements repressed by these pathways has not been reported. Here we show that in mouse embryonic stem cells (mESCs), the genes up-regulated following deletion of the H3K9 methyltransferase Setdb1 are distinct from those de-repressed in mESC deficient in the DNA methyltransferases Dnmt1, Dnmt3a and Dnmt3b, with the exception of a small number of primarily germline-specific genes. Numerous endogenous retroviruses (ERVs) lose H3K9me3 and are concomitantly de-repressed exclusively in SETDB1 knockout mESCs. Strikingly, ~15% of up-regulated genes are induced in association with de-repression of promoter proximal ERVs, half in the context of "chimaeric" transcripts that initiate within these retroelements and splice to genic exons. Thus, SETDB1 plays a previously unappreciated yet critical role in inhibiting aberrant gene transcription by suppressing the expression of proximal ERVs. Overall design: NChIP-seq and mRNA-seq of WT, SETDB1 KO and DMNT1 TKO mESCs
DNA methylation and SETDB1/H3K9me3 regulate predominantly distinct sets of genes, retroelements, and chimeric transcripts in mESCs.
No sample metadata fields
View SamplesThis SuperSeries is composed of the SubSeries listed below.
Identification and characterization of Hoxa9 binding sites in hematopoietic cells.
Sex, Specimen part, Cell line, Time
View SamplesThe molecular mechanism defining susceptibility of normal cells to oncogenic transformation may be a valuable therapeutic target. We characterized the cell of origin and its critical pathways in MN1 leukemias. Common myeloid (CMP), but not granulocyte-macrophage progenitors (CMP) could be transformed by constitutively overexpressed MN1. Complementation studies of CMP-signature genes in GMPs demonstrated that leukemogenicity of MN1 required the MEIS1/abdB-like HOX protein complex. Colocalization studies by ChIP-seq identified common chromatin targets of MN1 and MEIS1 that were associated with open chromatin and transcriptional activation. Transcriptional repression of MEIS1 target sites in established MN1 leukemias had antileukemic activity. As MN1 relies on but can not activate expression of MEIS1/abdB-like HOX proteins, transcriptional activity of these genes determines which cell is the cell of origin in MN1 leukemia.
Cell of origin in AML: susceptibility to MN1-induced transformation is regulated by the MEIS1/AbdB-like HOX protein complex.
Specimen part
View SamplesHepatocellular carcinoma (HCC) is the fifth most-common cancer worldwide causing nearly 600,000 deaths esch year. Approximately 80% of HCC develops on the background of cirrhosis.It is necessary to identify novel genes involved in HCC to implement new diagnostic and treatment options. However, the molecular pathogenesis of HCC largely remains unsolved. Only a few genetic alterations, namely those affecting p53, -catenin and p16INK4a have been implicated at moderate frequencies of these cancers. Early detection of HCC with appropriate treatment can decrease tumor-related deaths
Genome-wide transcriptional reorganization associated with senescence-to-immortality switch during human hepatocellular carcinogenesis.
Specimen part
View SamplesCellular senescence is a tumor suppressor mechanism, and immortalization facilitates neoplastic transformation. Both mechanisms may be highly relevant to hepatocellular carcinoma (HCC) development and its molecular heterogeneity. Cellular senescence appears to play a major role in liver diseases. Chronic liver diseases are associated with progressive telomere shortening leading senescence that is observed highly in cirrhosis, but also in some HCC. We previously described the generation of immortal and senescence-programmed clones from HCC-derived Huh7 cell line.
Genome-wide transcriptional reorganization associated with senescence-to-immortality switch during human hepatocellular carcinogenesis.
Sex, Specimen part
View SamplesIn summary, we characterized genomic signatures of response to drugs of abuse and we found positive correlations between the drug-induced expression and various behavioral effects. These signatures are formed by two dynamically inducible transcriptional networks: (1) CREB/SRF-dependent gene pattern that appears to be related to drug-induced neuronal activity, (2) the pattern of genes controlled at least in part via release of glucocorticoids and androgens that are associated with rewarding and harmful drug effects. The discovery of co-expressed networks of genes allowed for the identification of master-switch controlling factors involved in molecular response to the drugs. Finally, using the pharmacological tools we were able to dissect and inhibit particular gene expression patterns from genomic profile.
The dissection of transcriptional modules regulated by various drugs of abuse in the mouse striatum.
Compound, Time
View SamplesFindings suggest that PPARalpha plays a decisive role in the development of hypertrophy, affecting the functional outcome of the heart. Unfortunately, information on the nature of PPARalpha-dependent processes in cardiac hypertrophy is fragmentary and incomplete.
Transcriptomic analysis of PPARalpha-dependent alterations during cardiac hypertrophy.
No sample metadata fields
View SamplesThe remarkable feature of Schwann cells (SCs) to transform into a repair phenotype turned the spotlight on this powerful cell type. SCs provide the regenerative environment for axonal re-growth after peripheral nerve injury (PNI) and play a vital role in differentiation of neuroblastic tumors into a benign subtype of neuroblastoma, a tumor originating from neural crest-derived neuroblasts. Hence, understanding their mode-of-action is of utmost interest for new approaches in regenerative medicine, but also for neuroblastoma therapy. However, literature on human SCs is scarce and it is unknown to which extent human SC cultures reflect the SC repair phenotype developing after PNI in patients. We performed high-resolution proteome profiling and RNA-sequencing on highly enriched human SC and fibroblast cultures, control and ex vivo degenerated nerve explants to identify novel molecules and functional processes active in repair SCs. In fact, we found cultured SCs and degenerated nerves to share a similar repair SC-associated expression signature, including the upregulation of JUN, as well as two prominent functions, i.e., myelin debris clearance and antigen presentation via MHCII. In addition to myelin degradation, cultured SCs were capable of actively taking up cell-extrinsic components in functional phagocytosis and co-cultivation assays. Moreover, in cultured SCs and degenerated nerve tissue MHCII was upregulated at the cellular level along with high expression of chemoattractants and co-inhibitory rather than -stimulatory molecules. These results demonstrate human SC cultures to execute an inherent program of nerve repair and support two novel repair SC functions, debris clearance via phagocytosis-related mechanisms and type II immune-regulation. Overall design: mRNA of 27 samples were sequenced (50bp, single end) and analyzed. Biological replicates were performed.
Proteomics and transcriptomics of peripheral nerve tissue and cells unravel new aspects of the human Schwann cell repair phenotype.
Subject
View SamplesResveratrol is a naturally occurring compound that profoundly affects energy metabolism and mitochondrial function and serves as a calorie restriction mimetic, at least in animal models of obesity. Here we treated 10 healthy, obese men with placebo and 150 mg/day resveratrol in a randomized double-blind cross-over study for 30 days. Resveratrol supplementation significantly reduced sleeping- and resting metabolic rate. In muscle, resveratrol activated AMPK, increased SIRT1 and PGC-1alpha protein levels, increased citrate synthase activity, and improved muscle mitochondrial respiration on a fatty acid-derived substrate. Furthermore, resveratrol elevated intramyocellular lipid levels, and decreased intrahepatic lipid content, circulating glucose, triglycerides, alanine-aminotransferase, and inflammation markers. Systolic blood pressure dropped and HOMA index improved after resveratrol. In the postprandial state, adipose tissue lipolysis and plasma fatty acid and glycerol decreased. In conclusion, we demonstrate that 30 days of resveratrol supplementation induces profound metabolic changes in obese subjects, mimicking the effects of calorie restriction.
Calorie restriction-like effects of 30 days of resveratrol supplementation on energy metabolism and metabolic profile in obese humans.
Sex, Specimen part
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