ABSTRACT: Genome-wide map of HAEC chromatin landscape under resting and TNFa, IL1b, and OxPAPC stimulation, with corresponding transcription factor binding and RNA expression
Project description:We report the dynamic enhancer landscape of HAEC at baseline and under inflammatory stimulation, and also show the cistromes of ETS, AP-1 as well as key signal dependent transcription factors, with corresponding gene expression. We also describe the inflammatory transcriptional profile caused by inhibition of the ETS factor ERG with siRNA.
Project description:According to current models, transcription factors (TFs) activated by extracellular stimuli operate in the context of a pre-established enhancer repertoire induced and maintained by lineage-specific TFs. Here, we uncovered the existence of latent enhancers, defined as regions of the genome that in terminally differentiated cells are poorly accessible and lack the histone marks characteristic of enhancers, but readily acquire these features in response to extracellular cues. Stimulation of resting macrophages caused simultaneous binding of stimulus-activated TFs and lineage-determining TFs to these regions, enabling deposition of enhancer-specific features. Once unveiled, these enhancers did not return to a latent state even when stimulation ceased; instead, they persisted and mediated a faster and stronger response upon restimulation. We suggest that stimulus-specific expansion of the available cis-regulatory repertoire provides an epigenomic memory of the exposure to environmental agents. Poly(A) fraction of the total mRNA of resting and stimulated murine bone marrow derived macrophages was extracted and subjected to by multiparallel sequencing. Experiments carried out in untreated cells as well as in cells treated for 4hrs (IFNg, IL4, TNFa, TGFb1, IL1b, MALP2, CpG)
Project description:According to current models, transcription factors (TFs) activated by extracellular stimuli operate in the context of a pre-established enhancer repertoire induced and maintained by lineage-specific TFs. Here, we uncovered the existence of latent enhancers, defined as regions of the genome that in terminally differentiated cells are poorly accessible and lack the histone marks characteristic of enhancers, but readily acquire these features in response to extracellular cues. Stimulation of resting macrophages caused simultaneous binding of stimulus-activated TFs and lineage-determining TFs to these regions, enabling deposition of enhancer-specific features. Once unveiled, these enhancers did not return to a latent state even when stimulation ceased; instead, they persisted and mediated a faster and stronger response upon restimulation. We suggest that stimulus-specific expansion of the available cis-regulatory repertoire provides an epigenomic memory of the exposure to environmental agents. Chromatin immunoprecipitations of H3 lysine 4 mono-methylated, H3 lysine 27 acetylated, H3 lysine 4 tri-methylated, the transcription factor PU.1 and total RNA polymerase II followed by multiparallel sequencing performed in murine bone marrow-derived macrophages (BMDMs). Experiments were carried out in untreated cells as well as in cells treated for 4hrs (lipopolysaccharide (LPS), IFNg, IL4, TNFa, TGFb1, IL1b, MALP2, CpG) and 24hrs (LPS).
Project description:TNFα has an evolutionary conserved role in mediating inflammation via activation of the transcription factor NF-κB. The functions of individual NF-κB binding sites are not well understood. To identify conserved and functionally important NF-κB binding sites in mammals, we performed ChIP-seq to map the genome-wide binding of RELA and select histone modifications in primary vascular endothelial cells (ECs) isolated from the aortas of human (HAEC), mouse (MAEC) and cow (BAEC), before and after TNFα. The conserved RELA binding sites show strong epigenetic changes in response to TNFα and enrich near genes controlling vascular development and pro-inflammatory responses. Our method identifies novel modes of RELA-chromatin interactions that are conserved in mammals and shared between multiple cell-types. Particularly, genomic regions bound by RELA prior to stimulation are important responders during TNFα stimulation. We use CRISPR/Cas9 genome editing to validate the roles of the conserved RELA pre-bound sites near pro-inflammatory genes such as CCL2 and PLK2. Our evolutionary approach describes new aspects of mammalian NF-κB biology including its role within super-enhancers and relevance in inflammatory disorders.
Project description:Genome-wide analyses of the transcriptomes and transcription factor recruitment in estrogen receptor breast cancer cells in response to estradiol, IL1b, or TNFa treatments. Also, the role of inflammatory cytokines on affecting tamoxifen sensitivity is analyzed on a genome-wide scale.
Project description:Genome-wide association studies (GWAS-s) have linked thousands of genetic variants with complex diseases and traits. However, most genetic variants identified reside in non-coding regions of the genome making it hard to predict and understand the molecular mechanisms underlying causal alleles. We have previously performed molecular Quantitative Trait Locus (molQTL) analysis for transcription factor binding, chromatin accessibility, and H3K27 acetylation across primary Human Aortic Endothelial Cell (HAEC) samples. Here we expand this analysis to study more than 30,000 genetic variants using the massively parallel reporter assay (MPRA) STARR-Seq in immortalized HAEC cells (teloHAEC). We demonstrate that more than 5,000 variants exhibit differential expression between alleles and identify ETS and AP-1 motifs as the strongest sequence attributes—and cell type-specific chromatin accessibility as the strongest epigenetic attribute—associated with allele-specific regulatory activity. Using interleukin 1-beta (IL1b) as a modulator of cell state and environment, we observe robust evidence for context-specific SNP effects, thereby underscoring the prevalence of GxE effects on noncoding variant function. We integrate results from molQTL mapping and STARR-seq with eQTL data from HAECs and GTEx tissues to fine-map functional non-coding SNPs at GWAS loci for vascular diseases.
Project description:The study sought to determine the global miRNA profiles of mouse pancreatic cell lines aTC1-6 and bTC1 at steady state and after treatment with a cocktail of pro-inflammatory cytokines (IL1b; IFNg and TNFa) for a time course of 24 and 48 hours. Inflammatory cocktail contains IL1b 50 IU/ml; IFNg 1000 IU/ml; TNFa 1000 IU/ml. MicroRNA expression profiles in both cell lines during the different experimental conditions were determined using TaqMan® Rodent miRNA A+B Cards Set v2.0 (TLDA, Life Technologies). MicroRNA profiles were measured in 3 independent biological replicates.
Project description:MDA-MB-231 cells were treated with PBS, LPS, IL1b, TNFa, IL6, and TGFb respectively and expression profile were assayed by Arraystar human lncRNA array 2.0
