We decribe the accessible chormatin landscape in RAS-induced (RIS) and NOTCH induced senescence (NIS) using ATAC-seq. By expressing active NOTCH (N1ICD) in the context of RIS, we find that N1ICD antagonises the formation of accessible regions in RIS. By performing co-cultures, we demonstrate that cells expressing a NOTCH1 ligand, JAGGED1, can antagonise the formation of RIS specific accessible regions. Overall design: mRNA profiles were IMR90 cells expressing ER:HRAS(G12V) and a control vector or MSCV miR30 shHMGA1 were generated. 6 biological replicates.
NOTCH-mediated non-cell autonomous regulation of chromatin structure during senescence.
Cell line, Subject
View SamplesBreast cancer metastasis to bone is a critical determinant of long-term survival after treatment of primary tumors. We used a mouse model of spontaneous bone metastasis to determine new molecular mechanisms. Differential transcriptome comparisons of primary and metastatic tumor cells revealed that a substantial set of genes suppressed in bone metastases were highly enriched for promoter elements for the type I interferon (IFN) regulatory factor, Irf7, itself suppressed in mouse and human metastases. The critical function of the Irf7 pathway was demonstrated by restoration of exogenous Irf7 or systemic interferon administration, which significantly reduced bone metastases and prolonged metastasis-free survival. Using mice deficient in the type I receptor (Ifnar1-/-) or mature B, T and NK cell responses (NOD Scid IL-2r-/- mice), we demonstrated that Irf7-driven suppression of metastasis was reliant on IFN signaling to host immune cells. Metastasis suppression correlated with decreased accumulation of myeloid-derived suppressor cells and increased CD4++, CD8 T cells and NK cells in the peripheral blood and was reversed by depletion of CD8+ cells and NK cells. Clinical importance of our findings was demonstrated as increased primary tumor Irf7 expression predicted prolonged bone and lung metastasis-free survival. Thus we report for the first time, a novel innate immune pathway, intrinsic to breast cancer cells, whose suppression in turn restricts systemic immunosurveillance to enable metastasis. This pathway may constitute a novel therapeutic target for restricting breast cancer metastases.
Silencing of Irf7 pathways in breast cancer cells promotes bone metastasis through immune escape.
Specimen part
View SamplesDominantly inherited expanded repeat neurodegenerative diseases are typically caused by the expansion of existing variable copy number tandem repeat sequences in otherwise unrelated genes. Repeats located in translated regions encode polyglutamine that is thought to be the toxic agent, however in several instances the expanded repeat is in an untranslated region, necessitating multiple pathogenic pathways or an alternative common toxic agent. As numerous clinical features are shared by several of these diseases, and expanded repeat RNA is a common intermediary, RNA has been proposed as a common pathogenic agent. Various forms of repeat RNA are toxic in animal models, by multiple distinct pathways. In Drosophila, repeat-containing double-stranded RNA (rCAG.rCUG~100) toxicity is dependent on Dicer processing evident with the presence of single-stranded rCAG7, which have been detected in affected HD brains. Microarray analysis of Drosophila rCAG.rCUG~100 repeat RNA toxicity revealed perturbation of several pathways including innate immunity. Recent reports of elevated circulating cytokines prior to clinical onset, and age-dependent increased inflammatory signaling and microglia activation in the brain, suggest that immune activation precedes neuronal toxicity. Since the Toll pathway is activated by certain forms of RNA, we assessed the role of this pathway in RNA toxicity. We find that rCAG.rCUG~100 activates Toll signaling and that RNA toxicity is dependent on this pathway. The sensitivity of RNA toxicity to autophagy further implicates innate immune activation. Expression of rCAG.rCUG~100 was therefore directed in glial cells and found to be sufficient to cause neuronal dysfunction. Non-autonomous toxicity due to expanded repeat-containing double-stranded RNA mediated activation of innate immunity is therefore proposed as a candidate pathway for this group of human genetic diseases.
Distinct roles for Toll and autophagy pathways in double-stranded RNA toxicity in a Drosophila model of expanded repeat neurodegenerative diseases.
Sex, Specimen part, Disease
View SamplesThis SuperSeries is composed of the SubSeries listed below.
Independence of repressive histone marks and chromatin compaction during senescent heterochromatic layer formation.
Sex, Cell line, Treatment
View SamplesThe expansion of repressive epigenetic marks has been implicated in heterochromatin formation during embryonic development, but the general applicability of this mechanism is unclear. Here we show that nuclear rearrangement of repressive histone marks H3K9me3 and H3K27me3 into non-overlapping structural layers characterizes senescence-associated heterochromatic foci (SAHF) formation in human fibroblasts. However, the global landscape of these repressive marks remains unchanged upon SAHF formation, suggesting that in somatic cells heterochromatin can be formed through the spatial repositioning of pre-existing repressively marked histones. This model is reinforced by the correlation of pre-senescent replication timing with both the subsequent layered structure of SAHFs and the global landscape of the repressive marks, allowing us to integrate microscopic and genomic information. Furthermore, modulation of SAHF structure does not affect the occupancy of these repressive marks nor vice versa. These experiments reveal that high-order heterochromatin formation and epigenetic remodeling of the genome can be discrete events.
Independence of repressive histone marks and chromatin compaction during senescent heterochromatic layer formation.
Sex, Cell line, Treatment
View SamplesTo compare the gene expression profiles of unpassaged, proliferating HUVEC and human iris, retinal and choroidal microvascular endothelial cells.
Comparative gene expression profiling of human umbilical vein endothelial cells and ocular vascular endothelial cells.
Specimen part
View SamplesCardiac structural changes associated with dilated cardiomyopathy (DCM) include cardiomyocyte hypertrophy and myocardial fibrosis. Connective Tissue Growth Factor (CTGF) has been associated with tissue remodeling and is highly expressed in failing hearts. To test if inhibition of CTGF would alter the course of cardiac remodeling and preserve cardiac function in the protein kinase C (PKC) mouse model of DCM. Transgenic mice expressing constitutively active PKC in cardiomyocytes develop cardiac dysfunction that was evident by 3 months of age, and that progressed to heart failure, cardiac fibrosis, and increased mortality. Beginning at 3 months of age, mice were treated with an antibody to CTGF (FG-3149) or non-immune IgG control antibody for an additional 3 months. CTGF inhibition significantly improved left ventricular (LV) systolic and diastolic function in PKC mice, and slowed the progression of LV dilatation. Using gene arrays and quantitative PCR, the expression of many genes associated with tissue remodeling were elevated in PKC mice, but significantly decreased by CTGF inhibition, however total collagen deposition was not attenuated. The observation of significantly improved LV function by CTGF inhibition in PKC mice suggests that CTGF inhibition may benefit patients with DCM.
Connective tissue growth factor regulates cardiac function and tissue remodeling in a mouse model of dilated cardiomyopathy.
Sex, Specimen part, Treatment
View SamplesRecent evidence supports a role for RNA as a common pathogenic agent in both the polyglutamine and untranslated dominant expanded repeat disorders. One feature of all repeat sequences currently associated with disease is their predicted ability to form a hairpin secondary structure at the RNA level. In order to investigate mechanisms by which hairpin forming repeat RNAs could induce neurodegeneration, we have looked for alterations in gene transcripts as hallmarks of the cellular response to toxic hairpin repeat RNAs. Three disease associated repeat sequences - CAG, CUG and AUUCU - were specifically expressed in the neurons of Drosophila and resultant common, early, transcriptional changes assessed by microarray analyses. Transcripts that encode several components of the Akt/Gsk3- signalling pathway were altered as a consequence of expression of these repeat RNAs, indicating that this pathway is a component of the neuronal response to these pathogenic RNAs and may represent an important common therapeutic target in this class of diseases.
Perturbation of the Akt/Gsk3-β signalling pathway is common to Drosophila expressing expanded untranslated CAG, CUG and AUUCU repeat RNAs.
Sex, Age, Specimen part
View SamplesNeuroprotective therapies for retinal degeneration may be used to rescue retinal cells and preserve vision. Hypoxic preconditioning stabilizes the transcription factor HIF-1 in the retina and strongly protects photoreceptors in an animal model of light-induced retinal degeneration.
Analysis of the retinal gene expression profile after hypoxic preconditioning identifies candidate genes for neuroprotection.
No sample metadata fields
View SamplesTotal RNA was isolated from HuH-7 cells after transfection of IGF-II specific siRNAs. Gene expression profiling was performed using the Affymetrix Human Genome U133A 2.0 Arrays. The raw data were analysed using mixed model ANOVA.
Autocrine insulin-like growth factor-II stimulation of tumor cell migration is a progression step in human hepatocarcinogenesis.
No sample metadata fields
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