Genome-wide discovery of multiple sclerosis genetic risk variant allelic regulatory activity
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ABSTRACT:
ORGANISM(S): Homo sapiens
PROVIDER: GSE293036 | GEO | 2025/11/13
REPOSITORIES: GEO
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Project description:Background Atopic dermatitis (AD) is an inflammatory, pruritic disease of the skin with a complex etiology involving environmental and genetic factors. Numerous genetic risk loci for AD have been nominated through genome-wide association studies, with most associated variants residing in non-coding regions. However, further work is needed to understand how genetic variation contributes to disease-related alterations to gene expression. Objective Here, we use massively parallel reporter assays (MPRAs) to identify genetic risk variants with genotype-dependent regulatory activity within a set of 2,381 variants distributed among 49 independent atopic dermatitis risk loci. Methods We employed our MPRA library in HaCaT skin keratinocytes, TE-7 esophageal epithelial cells, and Jurkat T cells, enabling the identification of shared and cell-type specific variants with genotype-dependent enhancer activity. Stimulation of HaCaT and TE-7 cells with the cytokine IL-13 revealed 14 variants with stimulation-dependent allelic expression patterns, elucidating a likely role for genotypic variation in Th2-mediated inflammatory signaling in AD. Results In total, our approach discovered 96 allelic enhancer variants among all investigated cellular contexts, representing 32 independent AD risk loci. We discover a possible mechanistic role for AP-1 family transcription factors, as revealed by motif enrichment, genotype-dependent binding, and enhanced ChIP-seq signal at AD risk variants with allelic enhancer activity compared to variants with non-allelic enhancer activity. We assign allelic enhancer variants to probable target genes, including previously identified risk genes such as KIF3A and FLG. Conclusion Collectively, our systematic, genome-scale approach implicates causal genotype-dependent gene regulatory mechanisms for the majority of AD risk loci, providing a unique resource for the discovery of the genetic mechanisms underlying this chronic inflammatory disease.
2025-08-19 | GSE300756 | GEO
Project description:Genome-wide association studies of Systemic Lupus Erythematosus (SLE) nominate 3,073 genetic variants at 91 risk loci. To systematically screen these variants for allelic transcriptional enhancer activity, we constructed a massively parallel reporter assays (MPRA) library comprising 12,396 DNA oligonucleotides containing the genomic context around every allele of each SLE variant. Transfection into Epstein-Barr virus-transformed B cell line GM12878 revealed 482 variants with enhancer activity, with 51 variants showing genotype-dependent (allelic) enhancer activity at 27 risk loci. Combined with allelic enhancer activity analyses in Jurkat cell line, we identified shared and unique allelic transcriptional regulatory mechanisms at SLE risk loci. In-depth analysis of allelic transcription factor (TF) binding at and around 51 allelic variants identified one class of TFs whose DNA-binding motif tends to be directly altered by the risk variant and a second, larger class of TFs that also bind allelically but do not have their motifs directly altered by the variant. Collectively, our approach provides a blueprint for the discovery of allelic gene regulation at risk loci for any disease and offers insight into the transcriptional regulatory mechanisms underlying SLE.
2021-01-31 | GSE143792 | GEO
Project description:Introduction: Cis-acting regulatory single nucleotide polymorphisms (SNPs) at specific loci may modulate penetrance of germline mutations at the same loci by introducing different levels of expression of the wild-type allele. We have previously reported that BRCA2 shows differential allelic expression and we hypothesize that the known variable penetrance of BRCA2 mutations might be associated with this mechanism. Methods: We combined haplotype analysis and differential allelic expression of BRCA2 in breast tissue to identify expression haplotypes and candidate cis-regulatory variants. These candidate variants underwent selection based on in-silico predictions for regulatory potential and disruption of transcription factor binding, and were functionally analysed in-vitro and in-vivo in normal and breast cancer cell lines. SNPs tagging the expression haplotypes were correlated with the total expression of several genes in breast tissue measured by Taqman and microarray technologies. The effect of the expression haplotypes on breast cancer risk in BRCA2 mutation carriers was investigated in 2754 carriers. Results: We identified common haplotypes associated with differences in the levels of BRCA2 expression in human breast cells. We characterised three cis-regulatory SNPs located at the promoter and two intronic regulatory elements, which affect the binding of the transcription factors C/EBPα, HMGA1, DBP and ZF5. We showed that the expression haplotypes also correlated with changes in the expression of other genes in normal breast. Furthermore, there was suggestive evidence that the minor allele of SNP rs4942440, which is associated with higher BRCA2 expression, is also associated with a reduced risk of breast cancer (per-allele HR=0.85, 95%CI=0.72-1.00, P-trend=0.048). Conclusion: Our work provides further insights into the role of cis-regulatory variation in the penetrance of disease-causing mutations. We identified small-effect genetic variants associated with allelic expression differences in BRCA2, which could possibly affect the risk in mutation carriers through altering expression levels of the wild-type allele. Genotype of normal breast sample from healthy controls.
2012-02-01 | E-GEOD-32258 | biostudies-arrayexpress
Project description:Eosinophilic esophagitis (EoE) is a rare atopic disorder associated with esophageal dysfunction, including difficulty swallowing, food impaction, and inflammation. EoE develops in a small subset of people with food allergies under the influence of environmental and genetic risk factors. Genome wide association studies (GWAS) have identified 31 independent risk loci for the disease, and linkage disequilibrium (LD) expansion of these loci nominates a set of 531 variants that are potentially causal. These risk variants are non-coding, suggesting a likely role in altered gene regulatory mechanisms. To systematically interrogate the gene regulatory activity of these variants, we designed a massively parallel reporter assay (MPRA) containing the alleles of each variant within their 170 bp genomic sequence context cloned into a GFP reporter library. Transfection of the MPRA library into TE-7 esophageal epithelial cells, HaCaT skin keratinocytes, and Jurkat T cells revealed cell-type-specific gene regulation. We identify 32 allelic enhancer variants (allelic enVars) that regulate reporter gene expression in a genotype-dependent manner in at least one cellular context. By annotating these variants with expression quantitative trait loci (eQTL) and chromatin looping data in related tissues and cell types, we identify putative target genes affected by genetic variation in EoE patients, including TSLP and multiple genes at the HLA locus. Transcription factor enrichment analyses reveal possible roles for cell-type specific regulators, including GATA-3, a key regulator of type 2 inflammation. Collectively, our approach reduces the large set of EoE-associated variants to a set of 32 with allelic regulatory activity, providing new functional insights into the effects of genetic variation in this disease.
2023-11-26 | GSE232336 | GEO
Project description:Eosinophilic esophagitis (EoE) is a rare atopic disorder associated with esophageal dysfunction, including difficulty swallowing, food impaction, and inflammation. EoE develops in a small subset of people with food allergies under the influence of environmental and genetic risk factors. Genome wide association studies (GWAS) have identified 31 independent risk loci for the disease, and linkage disequilibrium (LD) expansion of these loci nominates a set of 531 variants that are potentially causal. These risk variants are non-coding, suggesting a likely role in altered gene regulatory mechanisms. To systematically interrogate the gene regulatory activity of these variants, we designed a massively parallel reporter assay (MPRA) containing the alleles of each variant within their 170 bp genomic sequence context cloned into a GFP reporter library. Transfection of the MPRA library into TE-7 esophageal epithelial cells, HaCaT skin keratinocytes, and Jurkat T cells revealed cell-type-specific gene regulation. We identify 32 allelic enhancer variants (allelic enVars) that regulate reporter gene expression in a genotype-dependent manner in at least one cellular context. By annotating these variants with expression quantitative trait loci (eQTL) and chromatin looping data in related tissues and cell types, we identify putative target genes affected by genetic variation in EoE patients, including TSLP and multiple genes at the HLA locus. Transcription factor enrichment analyses reveal possible roles for cell-type specific regulators, including GATA-3, a key regulator of type 2 inflammation. Collectively, our approach reduces the large set of EoE-associated variants to a set of 32 with allelic regulatory activity, providing new functional insights into the effects of genetic variation in this disease.
2023-11-26 | GSE232337 | GEO
Project description:The major histocompatibility complex (MHC) region represents by far the strongest multiple sclerosis (MS) susceptibility loci. DNA methylation changes have been consistently detected at the MHC region in MS. However, understanding the full picture of epigenetic regulations of MHC in MS remains challenging, due in part to the limited coverage in the region by standard whole genome bisulfite sequencing or array-based methods. To fill this gap, we utilized a novel but validated MHC capture protocol with bisulfite sequencing and conducted a comprehensive analysis of MHC methylation landscapes in blood samples from 147 treatment naïve MS participants and 129 healthy controls. We identified 132 differentially methylated region (DMRs) within MHC regions and found they are significantly overlapped with MS risk variants. Integration of the MHC methylome to human leukocyte antigen (HLA) genetic data further indicate that the methylation changes are significantly associated with HLA genotypes. Using DNA methylation quantitative trait loci (mQTL) mapping and the causal inference test (CIT), we identified 643 cis-mQTL-DMRs paired associations including 71 DMRs possibly mediating causal relationships between 55 SNPs and MS risk.
2023-11-28 | GSE235106 | GEO
Project description:Introduction: Cis-acting regulatory single nucleotide polymorphisms (SNPs) at specific loci may modulate penetrance of germline mutations at the same loci by introducing different levels of expression of the wild-type allele. We have previously reported that BRCA2 shows differential allelic expression and we hypothesize that the known variable penetrance of BRCA2 mutations might be associated with this mechanism. Methods: We combined haplotype analysis and differential allelic expression of BRCA2 in breast tissue to identify expression haplotypes and candidate cis-regulatory variants. These candidate variants underwent selection based on in-silico predictions for regulatory potential and disruption of transcription factor binding, and were functionally analysed in-vitro and in-vivo in normal and breast cancer cell lines. SNPs tagging the expression haplotypes were correlated with the total expression of several genes in breast tissue measured by Taqman and microarray technologies. The effect of the expression haplotypes on breast cancer risk in BRCA2 mutation carriers was investigated in 2754 carriers. Results: We identified common haplotypes associated with differences in the levels of BRCA2 expression in human breast cells. We characterised three cis-regulatory SNPs located at the promoter and two intronic regulatory elements, which affect the binding of the transcription factors C/EBPα, HMGA1, DBP and ZF5. We showed that the expression haplotypes also correlated with changes in the expression of other genes in normal breast. Furthermore, there was suggestive evidence that the minor allele of SNP rs4942440, which is associated with higher BRCA2 expression, is also associated with a reduced risk of breast cancer (per-allele HR=0.85, 95%CI=0.72-1.00, P-trend=0.048). Conclusion: Our work provides further insights into the role of cis-regulatory variation in the penetrance of disease-causing mutations. We identified small-effect genetic variants associated with allelic expression differences in BRCA2, which could possibly affect the risk in mutation carriers through altering expression levels of the wild-type allele. Total gene expression of normal breast sample from healthy controls. This submission represents transcriptome component of study.
2012-02-01 | E-GEOD-32124 | biostudies-arrayexpress
Project description:Genetic variants in gene regulatory sequences can modify gene expression and mediate the molecular response to environmental stimuli. In addition, genotype–environment interactions (GxE) contribute to complex traits such as cardiovascular disease. Caffeine is the most widely consumed stimulant and is known to produce a vascular response. To investigate GxE for caffeine, we treated vascular endothelial cells with caffeine and used a massively parallel reporter assay to measure allelic effects on gene regulation for over 43,000 genetic variants. We identified 665 variants with allelic effects on gene regulation and 6 variants that regulate the gene expression response to caffeine (GxE, false discovery rate [FDR] < 5%). When overlapping our GxE results with expression quantitative trait loci colocalized with coronary artery disease and hypertension, we dissected their regulatory mechanisms and showed a modulatory role for caffeine. Our results demonstrate that massively parallel reporter assay is a powerful approach to identify and molecularly characterize GxE in the specific context of caffeine consumption.
2024-02-26 | GSE221514 | GEO
Project description:Using Massively Parallel Reporter Assays (MPRAs), we functionally screened over 1,000 SNPs, prioritized from 39 neuropsychiatric trait/disease GWAS loci based on overlap with predicted regulatory features—including expression quantitative trait loci (eQTL) and histone marks—from human brains and cell cultures. Using mouse neuroblastoma Neuro2a (N2a) cells, we identify over 100 SNPs with allelic effects on expression. Functional SNPs were enriched for binding sequences of retinoic acid-receptive transcription factors (TFs); with additional allelic differences unmasked in cells treated with all-trans retinoic acid (ATRA). Motifs overrepresented at functional SNPs corresponded to a set of TFs highly specific to serotonergic neurons and collectively downregulated in schizophrenia. Our application of MPRAs to screen MDD-associated SNPs suggested a shared transcriptional regulatory program across loci, a subset of which are unmasked by retinoids. Additional code and results corresponding to this GEO submission can be found at https://bitbucket.org/jdlabteam/n2a_atra_mdd_mpra_paper/src
2021-06-30 | GSE167517 | GEO
Project description:Coronary artery disease (CAD) is a complex disorder with genetic and environmental influences. Genome-wide association studies (GWAS) have identified over 300 genomic loci associated with disease risk. However, identifying the functional variants within these loci has been limited in large part due to linkage disequilibrium. This represents a critical step in understanding the molecular mechanisms underlying disease risk. To identify and prioritize candidate causal CAD-associated variants, we performed lentivirus-based massively parallel reporter assays (lentiMPRAs) in primary vascular smooth muscle cells (SMCs), which play significant roles in atherosclerosis, the underlying cause of CAD. We tested 25892 CAD-associated variants for their allele-specific enhancer activity in quiescent and proliferative SMCs, modeling healthy and disease conditions. We identified 122 candidate variants showing significant enhancer activity and differences in reporter gene expression between risk and non-risk alleles. We also identified 23 variants showing condition-biased allelic imbalance and 41 variants showing sex-biased allelic imbalance. We further functionally characterized 25892 variants by performing CUT&RUN assays to identify variants in enhancer and promoter regions of SMCs. By integrating the results of these experiments, we identified a credible set of 49 CAD-associated variants in functionally relevant regions. Furthermore, by comparing these identified variants with our previously obtained expression quantitative trait loci (eQTL) data, 27 of these 49 variants were associated with SMC gene expression levels. Finally, we performed CRISPRi experiments on 8 variants comprising 9 variant-gene pairs, rs35976034 (MAP1S), rs4888409 (CFDP1), rs73193808 (MAP3K7CL), rs67631072 (INPP5B/FHL3), rs1651285 (SNHG18), rs17293632 (SMAD3), rs2238792 (ARVCF), rs4627080 (NRIP3), to confirm their regulatory potential of nearby gene expression. Taken together, our results comprehensively fine-map the causal variants that confer increased risk of CAD through their effects on vascular smooth muscle cells.
2024-10-14 | GSE279300 | GEO