Enhancer connectome nominates target genes of inherited risk variants from inflammatory skin disorders.

The vast majority of polymorphisms for human dermatologic diseases fall in non-coding DNA regions, leading to difficulty interpreting their functional significance. Recent work utilizing chromosome conformation capture (3C) technology in combination with chromatin immunoprecipitation (ChIP) has provided a systematic means of linking non-coding variants within active enhancer loci to putative gene targets. Here, we apply H3K27ac HiChIP high-resolution contact maps, generated from primary human T-cell subsets (CD4+ Naïve, TH 17, and Treg ), to 21 dermatologic conditions associated with single nucleotide polymorphisms (SNPs) from 106 genome-wide association studies (GWAS). This "enhancer connectome" identified 1,492 HiChIP gene-targets from 542 non-coding SNPs (p<5.0x10-8 ). SNP-containing enhancers from inflammatory skin conditions were significantly enriched within the human leukocyte antigen (HLA)-locus, and also targeted several key factors from the JAK-STAT signaling pathway, while non-immune conditions did not. A focused profiling of systemic lupus erythematosus (SLE) HiChIP-genes identified enhancer interactions with factors important for effector CD4+ T-cell differentiation and function, including interferon regulatory factor 8 (IRF8) and members of the Ikaros family of zinc-finger proteins. Our results demonstrate the ability of the enhancer connectome to nominate functionally-relevant candidates from GWAS-identified variants, representing a powerful tool to guide future studies into the genomic regulatory mechanisms underlying dermatologic diseases.