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 SamplesWe report a novel mechanism of the interaction between perivascular cell and TAMs in promoting metastasis through the IL-33-ST2-dependent pathway. IL-33 was the highest up-regulated gene through activation of SOX7 transcription factor in PDGF-BB-stimulated pericytes. Gain- and loss-of-function experiments validate that IL-33 promotes metastasis through recruitment of TAMs. Il33-/- deficient mice showed impaired TAM recruitment and metastasis. Pharmacological inhibition of the IL-33-ST2 signalling by a soluble ST2 significantly inhibited TAMs and metastasis. Genetic deletion of host IL-33 in mice also blocked PDGF-BB-induced TAM recruitment and metastasis. High IL-33 in human cancers correlated with poor survival prognosis. These findings shed novel mechanisms of tumour stroma in promoting metastasis and have therapeutic implications for cancer therapy.
Molecular mechanisms of IL-33-mediated stromal interactions in cancer metastasis.
Specimen part
View SamplesCD4 T cells are essential mediators of the asthmatic process. We used the clinically relevant allergen house dust mites to induce signs of allergy in mice and performed gene expression arrays specifically on CD4 T cells infiltrating the lung
Interleukin-21-Producing CD4(+) T Cells Promote Type 2 Immunity to House Dust Mites.
Specimen part, Treatment
View SamplesTissue-resident macrophages can derive from yolk sac macrophages, fetal liver monocytes or adult bone marrow monocytes. Whether these precursors can give rise to transcriptionally identical alveolar macrophages is unknown. Here, we transferred traceable yolk sac macrophages, fetal liver monocytes, adult bone marrow monocytes or adult alveolar macrophages as a control, into the empty alveolar macrophage niche of neonatal Csf2rb-/- mice. All precursors efficiently colonized the alveolar niche and generated alveolar macrophages that were transcriptionally almost identical, with only 22 genes that could be linked to their origin. Underlining the physiological relevance of our findings, all transfer-derived alveolar macrophages self-maintained within the lungs for up to 1 year and durably prevented alveolar proteinosis. Thus, precursor origin does not affect the development of functional self-maintaining tissue-resident macrophages.
Yolk Sac Macrophages, Fetal Liver, and Adult Monocytes Can Colonize an Empty Niche and Develop into Functional Tissue-Resident Macrophages.
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 SamplesiNKT cells are innate-like lymphocytes that protect against infection, autoimmune disease, and cancer. However, little is known about epigenetic regulation of iNKT cell development. Here, we show that the H3K27me3 histone demethylase UTX is an essential cell-intrinsic factor that controls an iNKT lineage specific gene expression program and epigenetic landscape in a demethylase activity dependent manner. UTX deficient iNKT cells exhibit impaired expression of iNKT signature genes due to a decrease in activation-associated H3K4me3 and an increase in repressive H3K27me3 marks within the promoters that UTX occupies. Notably, we identified JunB as a novel regulator of iNKT development that partners with UTX to establish an iNKT lineage specific gene expression program. Moreover, we demonstrate that UTX-mediated regulation of super-enhancer accessibility is a key mechanism for iNKT lineage commitment. These findings uncover how UTX regulates iNKT cell development through multiple epigenetic mechanisms.
The histone demethylase UTX regulates the lineage-specific epigenetic program of invariant natural killer T cells.
Specimen part
View SamplesmRNA expression levels in synovial fibroblasts in 6 rheumatoid arthritis patients versus 6 osteoarthritis patients.
Constitutive upregulation of the transforming growth factor-beta pathway in rheumatoid arthritis synovial fibroblasts.
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