H3K27ac ChIP-seq in primary inflammatory (TPP) macrophages

We investigated an intergenic haplotype on chr21q22, linked to five different inflammatory diseases, and identified the molecular mechanism by which the risk haplotype increases expression of the causal gene, ETS2. This mechanism was predicted to alter enhancer activity at the disease-associated locus. We therefore performed H3K27ac ChIP-seq in inflammatory macrophages from minor and major allele homozygotes at the causal allele and investigated the effect on enhancer activity. In doing so, we mechanistically delineated how the risk haplotype increases expression of ETS2.

Type: Other
Archiver: European Genome-Phenome Archive (EGA)

1 Dataset

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Dataset ID	Description	Technology	Samples
EGAD00001011351	This dataset consists of H3K27ac ChIP-sequencing in inflammatory (TPP) macrophages from 2 minor allele homozygotes and 2 major allele homozygotes at rs2836882. Monocytes were positively selected from PBMC using CD14 Microbeads and inflammatory macrophage differentiation performed using conditions that model chronic inflammation (TPP): 3 days GM-CSF (50ng/mL) followed by 3 days GM-CSF, TNFa (50ng/mL), PGE2 (1mg/mL), and Pam3CSK4 (1mg/mL). After harvesting, cells were cross-linked, quenched, lysed, and sheared. Immunoprecipitation of histone-DNA complexes was performed overnight at 4C with rotation using an anti-H3K27ac antibody and the SimpleChIP Plus Sonication ChIP kit (Cell Signaling Technology). Following reverse cross-linking, 50ng of immunoprecipitated DNA or input DNA were used to prepare sequencing libraries using the iDeal Library Preparation kit (Diagenode), according to manufacturer instructions. 10 PCR cycles were used for the amplification step and size selection was not performed. The quality and molarity of all libraries was assessed using a BioAnalyzer 2100 (Agilent) and the libraries were sequenced in pools of 8, with each pool being sequenced in 2 lanes of an Illumina HiSeq2500 high output flow-cell (50bp, single-end reads). Raw data are provided as raw and aligned single-end sequencing reads from H3K27ac-bound DNA and the input chromatin. Raw reads were trimmed using Trim Galore and aligned to the reference human genome (hg19) using Burrows-Wheeler Aligner (v0.7.12) with default parameters. Aligned reads were converted to BAM files, sorted, and technical duplicates merged before indexing – all using SAMtools (v1.4). PCR duplicates were identified using Picard tools (v2.18.1) and removed together with unmapped reads using SAMtools (v1.4). The resulting BAM files were re-sorted and indexed after filtering.	Illumina HiSeq 2500	8