Converting 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 SamplesNeuronal, endocrine and exocrine cells exhibit regulated exocytosis but there is also a body of evidence for regulated exocytosis from other cell types. Myofibroblasts are a stromal cell type that secretes extracellular matrix proteins, growth factors and cytokines; they are important in wound healing and increasingly are recognised to play a role in modifying the cellular microenvironment in cancer. We have established calcium dependent regulated secretion in a subset of myofibroblasts from gastric cancers, adjacent tissue and from normal tissue. We have used microarrays to look for the expression of genes associated with the regulated secretory phenotype.
The neuroendocrine phenotype of gastric myofibroblasts and its loss with cancer progression.
Specimen part
View SamplesNitric oxide regulates plant development and responses to stress. However, the mechanisms underlying its regulatory role are still poorly known, and the impact of endogenous NO on the genome-wide transcriptome of plants has not been studied. For that purpose, we compared the transcriptomes of NO-deficient nia1nia2, noa1-2 and nia1nia2noa1-2 mutant versus wild type Arabidopsis thaliana plants. A core comprising 66 NO-responsive genes with similar expression in all NO-deficient genotypes was identified. Among them, 46 were down- and 20 up-regulated in NO-deficient plants, and thus positively and negatively regulated by endogenous NO, respectively. Accordingly with changes in its transcriptome, the NO-deficient nia1nia2noa1-2 mutant accumulated anthocyanins and indolic glucosinolates, displayed abnormal iron homeostasis in shoots and roots, and also showed altered root sensitivity to hormones such as ABA, ET, CYK and IAA. Together the presented data suggest NO functions essentially as a modulator of hormone action.
Nitric oxide sensing in plants is mediated by proteolytic control of group VII ERF transcription factors.
Specimen part
View SamplesAcetaminophen (APAP), a widely used analgesic and antipyretic that is considered to be relatively safe at recommended doses, is the leading cause of drug-induced liver failure in the United States. 3-Hydroxyacetanilide (AMAP), a regioisomer of acetaminophen is useful as a comparative tool for studying APAP-induced toxicity since it is non-toxic relative to APAP. TGF-alpha transgenic mouse hepatocytes were treated with both isomers to investigate mitogen-activated protein kinase cascades in order to differentiate their toxicological outcomes. Mitogen-activated protein kinase (MAPK) cascade expression and activation were measured using microarray and Bioplex technologies, respectively. APAP treatment led to c-Jun N-terminal kinase (JNK) activation, whereas AMAP treatment led to the activation of extracellular-signal-regulated protein kinase (ERK). The microarray data suggested APAP treatment may upregulate gene expression at multiple levels of the JNK cascade including a JNK-related scaffold protein. Expression data was related to phosphoprotein levels using the Bioplex system. APAP treatment led to a significant activation of JNK compared to its regioisomer. In contrast, microarray analysis of AMAP showed a slight upregulation of ERK gene activity. Furthermore, Bioplex data showed AMAP treatment led to significant ERK phosphorylation compared to APAP. Cell viability assays confirmed that APAP-induced activation of JNK was related to higher rates of cell death, whereas activation of ERK by AMAP may be cytoprotective.
Differential regulation of mitogen-activated protein kinase pathways by acetaminophen and its nonhepatotoxic regioisomer 3'-hydroxyacetanilide in TAMH cells.
Cell line
View SamplesCritically ill preterm infants experience multiple stressors while hospitalized. Morphine is commonly prescribed to ameliorate their pain and stress. We hypothesized that neonatal stress will have a dose-dependent effect on hippocampal gene expression, and these effects will be altered by morphine treatment. Male C57BL/6 mice were exposed to 5 treatment conditions between postnatal day 5 and 9: 1) Control, 2) mild stress + saline, 3) mild stress + morphine, 4) severe stress + saline and 5) severe stress + morphine. Hippocampal RNA was extracted and analyzed using Affymetrix Mouse Gene 1.0 ST Arrays. Single gene analysis and gene set analysis were used to compare groups with validation by qPCR. Stress resulted in enrichment of genes sets related to fear response, oxygen carrying capacity and NMDA receptor synthesis. Morphine downregulated gene sets related to immune function. Stress plus morphine resulted in enrichment of mitochondrial electron transport gene sets, and down-regulation of gene sets related to brain development and growth. We conclude that neonatal stress alone influences hippocampal gene expression, morphine alters a subset of stress-related changes in gene expression and influences other gene sets. Stress plus morphine show interaction effects not present with either stimulus alone. These changes may alter neurodevelopment.
Effects of neonatal stress and morphine on murine hippocampal gene expression.
Sex, Specimen part, Treatment
View SamplesComparison of rosette leaves of two different RAP2.2 overexpressing lines with wild type leaves. The AP2/EREBP transcription factor RAP2.2 was shown to bind to a cis-acting motif within the phytoene synthase promoter from Arabidopsis. To investigate effects of increased RAP2.2 levels, two RAP2.2 overexpressing Arabidopsis thaliana (ecotype Wassilewskija) lines were generated: one line, nosr2, carried the nos promoter and showed a two-fold increase in RAP2.2 transcript level, the second line, cmr-5, carried four copies of the CaMV-35S enhancer and showed a 12-fold increase. However, neither weak nor strong increase in RAP2.2 transcript amounts had any effect on RAP2.2 protein levels as shown by Western blot analysis. The strong robustness of RAP2.2 protein levels towards transcriptional changes can be explained by specific protein degradation which includes SINAT2, an E3 ubiquitin ligase which was isolated using a two-hybrid approach. Accordingly, global gene expression analysis using both RAP2.2 overexpressing lines showed only minor transcriptional changes which are probably due to minor growth variation than to mechanisms involved in the down-regulation of RAP2.2 protein amounts.
Transcription factor RAP2.2 and its interacting partner SINAT2: stable elements in the carotenogenesis of Arabidopsis leaves.
Specimen part
View SamplesAim of the study was to characterize the transcriptional response of human primary renal proximal tubule epithelial cells (RPTEC) to low oxygen stress.
The histone demethylases JMJD1A and JMJD2B are transcriptional targets of hypoxia-inducible factor HIF.
Sex, Age, Specimen part, Disease, Disease stage
View SamplesThis SuperSeries is composed of the SubSeries listed below.
Transcriptional blood signatures distinguish pulmonary tuberculosis, pulmonary sarcoidosis, pneumonias and lung cancers.
Sex, Specimen part, Disease, Disease stage, Treatment, Race, Subject
View SamplesThis study used whole blood transcriptional signatures from patients with tuberculosis compared to those with similar pulmonary diseases, sarcoidosis, pneumonia and primary lung cancer. TB and sarcoidosis had similar signatures that were distinct from pneumonia and lung cancer.
Transcriptional blood signatures distinguish pulmonary tuberculosis, pulmonary sarcoidosis, pneumonias and lung cancers.
Sex, Specimen part, Disease, Disease stage, Race
View SamplesGene expression profiles generated from skeletal muscle biopsies taken from participants of the HERITAGE family study. Participants completed an endurance training regime in which a skeletal muscle biopsy was taken prior to the start and after the final session of the program. Biopsies were used to generate Affymetrix gene expression microarrays.
The Role of Eif6 in Skeletal Muscle Homeostasis Revealed by Endurance Training Co-expression Networks.
No sample metadata fields
View Samples