Atopic dermatitis-associated genetic variants regulate LOC100294145 expression implicating interleukin-27 production and type 1 interferon signaling.

BACKGROUND: Atopic dermatitis (AD) is a complex inflammatory disease with a strong genetic component. A singular approach of genome wide association studies (GWAS) can identify AD-associated genetic variants, but is unable to explain their functional relevance in AD. This study aims to characterize AD-associated genetic variants and elucidate the mechanisms leading to AD through a multi-omics approach. METHODS: GWAS identified an association between genetic variants at 6p21.32 locus and AD. Genotypes of 6p21.32 locus variants were evaluated against LOC100294145 expression in peripheral blood mononuclear cells (PBMCs). Their influence on LOC100294145 promoter activity was measured in vitro via a dual-luciferase assay. The function of LOC100294145 was then elucidated through a combination of co-expression analyses and gene enrichment with g:Profiler. Mendelian randomization was further used to assess the causal regulatory effect of LOC100294145 on its co-expressed genes. RESULTS: Minor alleles of rs116160149 and rs115388857 at 6p21.32 locus were associated with increased AD risk (p = 2.175 × 10(-8), OR = 1.552; p = 2.805 × 10(-9), OR = 1.55) and higher LOC100294145 expression in PBMCs (adjusted p = 0.182; 8.267 × 10(-12)). LOC100294145 expression was also found to be increased in those with AD (adjusted p = 3.653 × 10(-2)). The genotype effect of 6p21.32 locus on LOC100294145 promoter activity was further validated in vitro. Co-expression analyses predicted LOC100294145 protein's involvement in interleukin-27 and type 1 interferon signaling, which was further substantiated through mendelian randomization. CONCLUSION: Genetic variants at 6p21.32 locus increase AD susceptibility through raising LOC100294145 expression. A multi-omics approach enabled the deduction of its pathogenesis model comprising dysregulation of hub genes involved in type 1 interferon and interleukin 27 signaling.