Analysis of HEK293 cells lines expressing V336Y mutant mitochondrial ribosomal protein. Overall design: mRNA profiles of wild-type and V336Y mutant HEK293 cell culture samples generated by deep sequencing.
Mutant MRPS5 affects mitoribosomal accuracy and confers stress-related behavioral alterations.
Cell line, Subject
View SamplesConverting epithelial into mesenchymal cells through epithelial-mesenchymal transition (EMT) requires massive changes in gene expression. How this is brought about is currently not clear. Here we examined the impact of the EMT master regulator SNAIL1 on the FOXA family of transcription factors which are distinguished by their particular competence to induce chromatin reorganization for the activation of transcriptional enhancer elements. We show that the expression of SNAIL1 and FOXA genes is anti-correlated in transcriptomes of colorectal tumors and cell lines. In two cellular EMT models, ectopically expressed Snail1 downregulates FOXA factors and directly represses FOXA1. To elucidate how FOXA factors contribute to the control of epithelial gene expression, we determined by ChIP-seq data analysis FOXA chromosomal distribution in relation to chromatin structural features characterizing distinct states of transcriptional activity. This revealed a preferential localization of FOXA1 and FOXA2 to transcriptional enhancers at signature genes that distinguish epithelial from mesenchymal colon tumors. To validate the significance of this association, we investigated the impact of FOXA factors on structure and function of transcriptional enhancers at the epithelial genes CDH1, CDX2 and EPHB3. Expression of dominant negative FOXA2 led to chromatin condensation at these enhancer elements. Site- directed mutagenesis of FOXA binding sites in reporter gene constructs and by genome- editing in situ impaired enhancer activity and completely abolished the active chromatin state of the EPHB3 enhancer. Conversely, expression of FOXA factors in cells with inactive CDX2 and EPHB3 enhancers led to chromatin opening and de novo deposition of the H3K4me1 and H3K27ac marks. These findings establish the pioneer function of FOXA factors at enhancer regions of epithelial genes and demonstrate their essential role in maintaining enhancer structure and function. Thus, by repressing FOXA family members, Snail1 targets transcription factors at strategically important positions in gene-regulatory hierarchies which may facilitate transcriptional reprogramming during EMT.
SNAIL1-mediated downregulation of FOXA proteins facilitates the inactivation of transcriptional enhancer elements at key epithelial genes in colorectal cancer cells.
Cell line, Treatment
View SamplesThis SuperSeries is composed of the SubSeries listed below.
MicroRNA expression changes during interferon-beta treatment in the peripheral blood of multiple sclerosis patients.
Sex, Disease
View SamplesThe purpose of this study was to investigate the expression dynamics of mRNAs and microRNAs in response to subcutaneous IFN-beta-1b treatment (Betaferon, 250 g every other day) in patients with clinically isolated syndrome (CIS) suggestive of multiple sclerosis (MS) or relapsing-remitting type of the disease (RRMS).
MicroRNA expression changes during interferon-beta treatment in the peripheral blood of multiple sclerosis patients.
Sex, Disease
View SamplesTranslation and mRNA degradation are intimately connected, yet the mechanisms that regulate them are not fully understood. Here we examine the regulation of translation and mRNA stability in mouse embryonic stem cells (ESCs) and during differentiation. In contrast to previous reports, we found that transcriptional changes account for most of the molecular changes during ESC differentiation. Within ESCs translation level and mRNA stability are positively correlated. The RNA-binding protein DDX6 has been implicated in processes involving both translational repression and mRNA destabilization; in yeast DDX6 connects codon optimality and mRNA stability and in mammals DDX6 is involved in microRNA-mediated repression. We generated DDX6 KO ESCs and found that while there was minimal connection between codon usage and stability changes, the loss of DDX6 leads to the translational depression of microRNA targets. Surprisingly, the translational derepression of microRNA targets occurs without affecting mRNA stability. Furthermore, DDX6 KO ESCs share overlapping phenotypes and global molecular changes with ESCs that completely lack all microRNAs. Together our results demonstrate that the loss of DDX6 decouples the two forms of microRNA induced repression and emphasize that translational repression by microRNAs is underappreciated. Overall design: 4-thiouridine (4su) metabolic labeling was performed on mouse embryonic stem cells (ESCs) and Epiblast like cells (EpiLCs).
Decoupling the impact of microRNAs on translational repression versus RNA degradation in embryonic stem cells.
Specimen part, Disease, Subject
View SamplesThe role of chronic hepatitis C virus (HCV) in the pathogenesis of HCV-associated hepatocellular carcinoma (HCC) is not completely understood, particularly at the molecular level.
Genes involved in viral carcinogenesis and tumor initiation in hepatitis C virus-induced hepatocellular carcinoma.
Specimen part
View SamplesMitochondria are able to modulate cell state and fate during normal and pathophysiologic conditions through a nuclear mediated mechanism collectively termed as a retrograde response. Our previous studies in Drosophila have clearly established that progress through the cell cycle is precisely regulated by the intrinsic activity of the mitochondrion by specific signaling cascades mounted by the cell. As a means to further our understanding of how mitochondrial energy status affects nuclear control of basic cell decisions we have employed Affymetrix microarray-based transcriptional profiling of Drosophila S2 cells knocked down for the gene encoding subunit Va of the complex IV of the mitochondrial electron transport chain. The profiling data identifies up-regulation of glycolytic genes and metabolic studies confirm this increase in glycolysis. The transcriptional portrait which emerges implicates many signaling systems, including a p53 response, an insulin response, and up-regulation of conserved mitochondrial responses. This rich dataset provides many novel targets for further understanding the mechanism whereby the mitochondrion may direct cellular fate decisions. The data also provides a salient model of the shift of metabolism from a predominately oxidative state towards a predominately aerobic glycolytic state, and therefore provides a model of energy substrate management not unlike that found in cancer.
Expression profiling of attenuated mitochondrial function identifies retrograde signals in Drosophila.
Cell line
View SamplesThis SuperSeries is composed of the SubSeries listed below.
Integrated expression profiles of mRNA and miRNA in polarized primary murine microglia.
Specimen part
View SamplesThe aim of this study was to determine the role that miRNAs have on influencing murine microgial phenotypes under M1(LPS) and M2a (IL-4) stimulating conditions.
Integrated expression profiles of mRNA and miRNA in polarized primary murine microglia.
Specimen part
View SamplesBackground: Septic shock is a heterogeneous syndrome within which probably exist several biological subclasses. Discovery and identification of septic shock subclasses could provide the foundation for the design of more specifically targeted therapies. Herein we tested the hypothesis that pediatric septic shock subclasses can be discovered through genome-wide expression profiling. Methods: Genome-wide expression profiling was conducted using whole blood-derived RNA from 98 children with septic shock, followed by a series of bioinformatic approaches targeted at subclass discovery and characterization. Results: Three putative subclasses (subclasses A, B, and C) were initially identified based on an empiric, discovery-oriented expression filter and unsupervised hierarchical clustering. Statistical comparison of the 3 putative subclasses (ANOVA, Bonferonni correction, p < 0.05) identified 6,934 differentially regulated genes. K means clustering of these 6,934 genes generated 10 coordinately regulated gene clusters corresponding to multiple signaling and metabolic pathways, all of which were differentially regulated across the 3 subclasses. Leave one out cross validation procedures indentified 100 genes having the strongest predictive values for subclass identification. Forty-four of these 100 genes corresponded to signaling pathways relevant to the adaptive immune system and glucocorticoid receptor signaling, the majority of which were repressed in subclass A patients. Subclass A patients were also characterized by repression of genes corresponding to zinc-related biology. Phenotypic analyses revealed that subclass A patients were younger, had a higher illness severity, and a higher mortality rate than patients in subclasses B and C. Conclusions: Genome-wide expression profiling can identify pediatric septic shock subclasses having clinically relevant phenotypes.
Identification of pediatric septic shock subclasses based on genome-wide expression profiling.
Age, Specimen part, Disease, Disease stage
View Samples