Project description:We investigated the function of EGR1 in macrophage differentiation and activation. We generated EGR1 CHIP-seq and CUT-and-RUN data during GM-CSF induced macrophage differentiation, paired with ATAC-seq. We performed RNA-seq and CHIP-seq for H3K27ac in EGR1-depleted differentiated macrophages. Finally we generated RNA-seq data in activated macrophages with EGR1 overexpression.
Project description:Enhancers determine tissue-specific gene expression programs. Enhancers are marked by high histone H3 lysine 4 mono-methylation (H3K4me1) and by the acetyl-transferase p300, which has allowed genome-wide enhancer identification. However, the regulatory principles by which subsets of enhancers become active in specific developmental and/or environmental contexts are unknown. We exploited inducible p300 binding to chromatin to identify, and then mechanistically dissect, enhancers controlling endotoxin-stimulated gene expression in macrophages. In these enhancers, binding sites for the lineage-restricted and constitutive Ets protein PU.1 coexisted with those for ubiquitous stress-inducible transcription factors such as NF-kappaB, IRF, and AP-1. PU.1 was required for maintaining H3K4me1 at macrophage-specific enhancers. Reciprocally, ectopic expression of PU.1 reactivated these enhancers in fibroblasts. Thus, the combinatorial assembly of tissue- and signal-specific transcription factors determines the activity of a distinct group of enhancers. We suggest that this may represent a general paradigm in tissue-restricted and stimulus-responsive gene regulation. Chromatin immuno-precipitations of p300, PU.1 and mono-methylated H3 lysine 4 followed by multiparallel sequencing were performed in bone marrow-derived macrophages. Experiments for p300 and PU.1 were also carried out in cells treated for 2hrs with lipopolysaccharide (LPS). In case of p300, reads obtained from two different biological replicates were merged.
Project description:Macrophages are amongst the major targets of glucocorticoids (GC) as therapeutic anti-inflammatory agents. Here we show that GC treatment of mouse and human macrophages initiates a cascade of induced gene expression including many anti-inflammatory genes. Inducible binding of the glucocorticoid receptor (GR) was detected at candidate enhancers in the vicinity of induced genes in both species and this was strongly associated with canonical GR binding motifs. However, the sets of inducible genes, the candidate enhancers, and the GR motifs within them, were highly-divergent between the two species. This SuperSeries is composed of the SubSeries listed below. Refer to individual Series
Project description:Therapy-related myeloid neoplasms (t-MN) share many similarities with AML de novo in the elderly. One common factor is that they arise in the setting of chronic inflammation, likely due to advanced age or chemotherapy-induced senescence. Here, we examined the impact of haploinsufficient loss of the del(5q) tumor suppressor gene, EGR1, commonly deleted in high-risk MNs. In mice, under the exogenous inflammatory stress of either serial transplant or successive doses of the alkylating agent ENU, Egr1-haploinsufficient hematopoietic stem cells (HSCs) exhibit a clonal advantage. Complete loss of EGR1 function is incompatible with transformation; mutations of EGR1 are rare and are not observed in the remaining allele in del(5q) patients and complete knockout of Egr1 in mice leads to HSC exhaustion. Using chromatin immunoprecipitation sequencing (ChIP-seq), we identify EGR1 binding sites in human CD34+ cord blood-derived stem and progenitor cells (HSPCs) and show that EGR1 binds genes critical for stem cell differentiation, inflammatory signaling, and the DNA damage response. Notably, in the chromosome 5 sequences frequently deleted in patients, there is a significant enrichment of innate and inflammatory genes, which may confer a fitness advantage in an inflammatory environment. Short hairpin RNA (shRNA) mediated silencing of EGR1 biases HSPCs towards a self-renewal transcriptional signature. In the absence of EGR1, cells upregulate MYC-driven proliferative signals, downregulate CDKN1A (p21), disrupt the DNA damage response, and downregulate inflammation - adaptations anticipated to confer a relative fitness advantage for stem cells especially in an environment of chronic inflammation.
Project description:Using GRO-Seq, we find extensive regulation of enhancer RNAs (eRNA) within super-enhancers in response to lipopolysaccharide treatment in macrophages. Both activation and repression of gene expression are associated with super-enhancers and eRNA transcription dynamics. Co-treatment of LPS and the anti-inflammatory drug dexamethasone targeted specific super-enhancers by attenuating their eRNA expression, leading to reduced expression of key inflammatory genes. We propose that super-enhancers function as molecular rheostats integrating the binding profiles of key regulators to produce dynamic profiles of gene expression. Nascent transcriptome (GRO-Seq) analysis over a time course (0, 20, 60, 180 min) of Lipopolisaccharide and Dexamethasone signaling in mouse bone marrow-derived macrophages.
Project description:We applied single-molecule sequencing and high-throughput analysis to analyze the regulation of EGR1 transcription in iPAM cells. By obtaining more than 4 billion base sequences from chromatin immunoprecipitation DNA, we generated a genome-wide chromatin state map of transcriptional regulation of EGR1 transcription factors in iPAM cells. Then, we analyzed the influence of EGR1 transcription regulation on macrophages by analyzing the binding position of EGR1 transcription factor to the genome.
Project description:Enhancers determine tissue-specific gene expression programs. Enhancers are marked by high histone H3 lysine 4 mono-methylation (H3K4me1) and by the acetyl-transferase p300, which has allowed genome-wide enhancer identification. However, the regulatory principles by which subsets of enhancers become active in specific developmental and/or environmental contexts are unknown. We exploited inducible p300 binding to chromatin to identify, and then mechanistically dissect, enhancers controlling endotoxin-stimulated gene expression in macrophages. In these enhancers, binding sites for the lineage-restricted and constitutive Ets protein PU.1 coexisted with those for ubiquitous stress-inducible transcription factors such as NF-kappaB, IRF, and AP-1. PU.1 was required for maintaining H3K4me1 at macrophage-specific enhancers. Reciprocally, ectopic expression of PU.1 reactivated these enhancers in fibroblasts. Thus, the combinatorial assembly of tissue- and signal-specific transcription factors determines the activity of a distinct group of enhancers. We suggest that this may represent a general paradigm in tissue-restricted and stimulus-responsive gene regulation.
Project description:Genes expression in Ly6C+/F4/80+ inflammatory macrophages, CX3CR1+/F4/80+ tissue resident macrophages and Ly6G+/F4/80- neutrophils which were isolated from day 3 wounds in C57/B6 mice aged 8 weeks by cell sorting Ly6C+ macrophages expressed higher (over 5 folds) levels of 241 genes compared to CX3CR1+ macrophages, and 3382 genes compared to neutrophils
Project description:The integrated activity of cis-regulatory elements fine-tunes transcriptional programs of mammalian cells by recruiting cell type–specific as well as ubiquitous transcription factors (TFs). Despite their key role in modulating transcription, enhancers are still poorly characterized at the molecular level, and their limited DNA sequence conservation in evolution and variable distance from target genes make their unbiased identification challenging. The coexistence of high mono-methylation and low tri-methylation levels of lysine 4 of histone H3 is considered a signature of enhancers, but a comprehensive view of histone modifications associated to enhancers is still lacking. By combining chromatin immunoprecipitation (ChIP) with mass spectrometry, we investigated cis-regulatory regions in macrophages to comprehensively identify histone marks specifically associated with enhancers, and to profile their dynamics after transcriptional activation elicited by an inflammatory stimulation. The intersection of the proteomics data with ChIP-seq and RNA-seq analyses revealed the existence of novel subpopulations of enhancers, marked by specific histone modification signatures: specifically, H3K36me2/K4me1 marks transcribed enhancers, while H3K36me3/K4me1 and H3K79me2/K4me1 combinations mark distinct classes of intronic enhancers. Thus, our MS analysis of functionally distinct genomic regions revealed the combinatorial code of histone modifications, highlighting the potential of proteomics in addressing fundamental questions in epigenetics.