Project description:More than 200 asthma-associated genetic variants have been identified in genome-wide association studies (GWASs). Expression quantitative trait loci (eQTL) data resources can help identify causal genes of the GWAS signals, but it can be difficult to find an eQTL that reflects the disease state because most eQTL data are obtained from normal healthy subjects. We performed a blood eQTL analysis using transcriptomic and genotypic data from 436 Korean asthma patients. To identify asthma-related genes, we carried out colocalization and Summary-based Mendelian Randomization (SMR) analysis using the results of asthma GWASs and eQTL data. In addition, we compared the results of disease eQTL data and asthma-related genes with two normal blood eQTL data from Genotype-Tissue Expression (GTEx) project and a Japanese study. We identified 342,054 cis-eQTL and 2,931 eGenes from asthmatic eQTL analysis. We compared the disease eQTL results with GTEx and a Japanese study and found that 63.2 % of the 2,931 eGenes overlapped with the GTEx eGenes and 38.5 % with the Japanese eGenes. Following the integrated analysis of the asthmatic eQTL data with asthma GWASs, using colocalization and SMR methods, we identified 13 asthma-related genes specific to the Korean asthmatic eQTL data. We provided Korean asthmatic cis-eQTL data and identified asthma-related genes by integrating them with GWAS data. In addition, we suggested these asthma-related genes as therapeutic targets for asthma. We envisage that our findings will contribute to understanding the etiological mechanisms of asthma and provide novel therapeutic targets.
Project description:Rationale: To identify functionally relevant common genetic risk variants associated with idiopathic pulmonary fibrosis (IPF), we performed expression quantitative trait loci (eQTL) and methylation quantitative trait loci (mQTL) mapping, followed by co-localization of eQTL and mQTL with genetic association signals as well as mediation analysis. Methods: Illumina MEGA genotyping arrays, mRNA sequencing, and Illumina 850k methylation arrays were performed on lung tissue of participants with IPF (234 RNA and 345 DNA samples) and non-diseased control (188 RNA and 202 DNA samples). Transcriptome and methylome datasets were normalized for unknown batch effects using Probabilistic Estimation of Expression Residuals (PEER). eQTL, cell type-interaction eQTL, and mQTL analyses were performed in FastQTL and co-localization analysis in eCAVIAR separately for cases and controls. Benjamini-Hochberg false discovery rate was used for adjustment for multiple comparisons. Results: After appropriate adjustment, we identified 4,745 genes with significant eQTLs in controls and 6,047 in cases (FDR-adjusted p<0.05). Focusing on genetic variants within 10 primary IPF-associated genetic loci, we identified 27 eQTLs in controls and 24 eQTLs in cases (FDR-adjusted p<0.05). Among these signals, we identified association of rs35705950 with expression of MUC5B (Chr11 locus) and rs2076295 with expression of DSP (Chr6 locus) in both cases and controls. To address cell specificity, we performed cell type-interaction eQTL analysis and identified an association of rs2076295 with expression of DSP in smooth muscle cells. mQTL analysis identified CpGs in gene bodies of MUC5B (cg17589883) and DSP (cg08964675) associated with the lead variants in these two loci. eCAVIAR demonstrated strong co-localization of eQTL/mQTL and genetic signal in MUC5B (rs35705950) and DSP (rs2076295) in both cases and controls. Mediation analysis demonstrated partial mediation of the effect of common variants in MUC5B and DSP loci on disease risk though MUC5B and DSP gene expression. Functional validation of the mQTL in MUC5B demonstrates that the CpG is within a putative internal repressor element that interacts through a 3D loop with the enhancer containing the rs35705950 genetic variant. Conclusions: Using lung eQTL/mQTL, co-localization, and mediation analyses, we have established the functional validation of the common IPF genetic risk variants for MUC5B (rs35705950) and DSP (rs2076295). These results provide additional evidence that both MUC5B and DSP are involved in the etiology of IPF.
Project description:Rationale: To identify functionally relevant common genetic risk variants associated with idiopathic pulmonary fibrosis (IPF), we performed expression quantitative trait loci (eQTL) and methylation quantitative trait loci (mQTL) mapping, followed by co-localization of eQTL and mQTL with genetic association signals as well as mediation analysis. Methods: Illumina MEGA genotyping arrays, mRNA sequencing, and Illumina 850k methylation arrays were performed on lung tissue of participants with IPF (234 RNA and 345 DNA samples) and non-diseased control (188 RNA and 202 DNA samples). Transcriptome and methylome datasets were normalized for unknown batch effects using Probabilistic Estimation of Expression Residuals (PEER). eQTL, cell type-interaction eQTL, and mQTL analyses were performed in FastQTL and co-localization analysis in eCAVIAR separately for cases and controls. Benjamini-Hochberg false discovery rate was used for adjustment for multiple comparisons. Results: After appropriate adjustment, we identified 4,745 genes with significant eQTLs in controls and 6,047 in cases (FDR-adjusted p<0.05). Focusing on genetic variants within 10 primary IPF-associated genetic loci, we identified 27 eQTLs in controls and 24 eQTLs in cases (FDR-adjusted p<0.05). Among these signals, we identified association of rs35705950 with expression of MUC5B (Chr11 locus) and rs2076295 with expression of DSP (Chr6 locus) in both cases and controls. To address cell specificity, we performed cell type-interaction eQTL analysis and identified an association of rs2076295 with expression of DSP in smooth muscle cells. mQTL analysis identified CpGs in gene bodies of MUC5B (cg17589883) and DSP (cg08964675) associated with the lead variants in these two loci. eCAVIAR demonstrated strong co-localization of eQTL/mQTL and genetic signal in MUC5B (rs35705950) and DSP (rs2076295) in both cases and controls. Mediation analysis demonstrated partial mediation of the effect of common variants in MUC5B and DSP loci on disease risk though MUC5B and DSP gene expression. Functional validation of the mQTL in MUC5B demonstrates that the CpG is within a putative internal repressor element that interacts through a 3D loop with the enhancer containing the rs35705950 genetic variant. Conclusions: Using lung eQTL/mQTL, co-localization, and mediation analyses, we have established the functional validation of the common IPF genetic risk variants for MUC5B (rs35705950) and DSP (rs2076295). These results provide additional evidence that both MUC5B and DSP are involved in the etiology of IPF.
Project description:We performed RNA sequencing to produce expression quantitative trait loci (eQTL) database of Crohn's disease patients. Using this eQTL data, we tried to determine the most functionally relevant genes at the established Crohn’s disease loci identified in genome-wide association studies (GWAS) involving Asian populations and to find novel disease-associated genes.
Project description:The functional interpretation of GWAS remains challenging due to the cell-type dependent influences of genetic variants. Here, we generated comprehensive maps of expression quantitative trait loci (eQTL) for 659 microdissected human kidney samples and identified cell-type eQTLs by mapping interactions between cell type abundance and genotype. By partitioning heritability using stratified LD-score regression to integrate GWAS with scRNA-seq and snATAC-seq data, we prioritized proximal tubules in kidney function and endothelial cells and distal tubule segments in blood pressure pathogenesis. Bayesian colocalization analysis nominated more than 200 genes for kidney function and hypertension. Our study clarifies the mechanism of commonly used antihypertensive and renal protective drugs and identifies drug repurposing opportunities for kidney disease.
Project description:The functional interpretation of GWAS remains challenging due to the cell-type dependent influences of genetic variants. Here, we generated comprehensive maps of expression quantitative trait loci (eQTL) for 659 microdissected human kidney samples and identified cell-type eQTLs by mapping interactions between cell type abundance and genotype. By partitioning heritability using stratified LD-score regression to integrate GWAS with scRNA-seq and snATAC-seq data, we prioritized proximal tubules in kidney function and endothelial cells and distal tubule segments in blood pressure pathogenesis. Bayesian colocalization analysis nominated more than 200 genes for kidney function and hypertension. Our study clarifies the mechanism of commonly used antihypertensive and renal protective drugs and identifies drug repurposing opportunities for kidney disease.
Project description:Genome-wide association studies (GWAS) have identified over 300 loci associated with the inflammatory bowel diseases (IBD), but putative causal genes for most are unknown. We conducted the largest disease-focused expression quantitative trait loci (eQTL) analysis using colon tissue from 252 IBD patients to determine genetic effects on gene expression and potential contribution to IBD. Combined with two non-IBD colon eQTL studies, we identified 194 potential target genes for 108 GWAS loci. eQTL in IBD tissue were enriched for IBD GWAS loci colocalizations, provided novel evidence for IBD-associated genes such as ABO and TNFRSF14, and identified additional target genes compared to non-IBD tissue eQTL. IBD-associated eQTL unique to diseased tissue had distinct regulatory and functional characteristics with increased effect sizes. Together, these highlight the importance of eQTL studies in diseased tissue for understanding functional consequences of genetic variants, and elucidating molecular mechanisms and regulation of key genes involved in IBD.
Project description:Profiles of sequence variants that influence gene transcription are very important for understanding mechanisms that affect phenotypic variation and disease susceptibility. Using genotypes at 1.4 million SNPs and a comprehensive transcriptional profile of 15,454 coding genes and 6,113 lincRNA genes obtained from peripheral blood cells of 298 Japanese individuals, we mapped expression quantitative trait loci (eQTLs). We identified 3,804 cis-eQTLs (within 500 kb from target genes) and 165 trans-eQTLs (>500 kb away or on different chromosomes). Cis-eQTLs were often located in transcribed or adjacent regions of genes; among these regions, 5’ untranslated regions and 5’ flanking regions had the largest effects. Epigenetic evidence for regulatory potential accumulated in public databases explained the magnitude of the effects of our eQTLs. Cis-eQTLs were often located near the respective target genes, if not within genes. Large effect sizes were observed with eQTLs near target genes, and effect sizes were obviously attenuated as the eQTL distance from the gene increased. Using a very stringent significance threshold, we identified 165 large-effect trans-eQTLs. We used our eQTL map to assess 8,069 disease-associated SNPs identified in 1,436 genome-wide association studies (GWAS). We identified genes that might be truly causative, but GWAS might have failed to identify for 148 out of the GWAS-identified SNPs; for example, TUFM (P=3.3E-48) was identified for inflammatory bowel disease (early onset); ZFP90 (P=4.4E-34) for ulcerative colitis; and IDUA (P=2.2E-11) for Parkinson's disease. We identified four genes (P<2.0E-14) that might be related to three diseases and two hematological traits; each expression is regulated by trans-eQTLs on a different chromosome than the gene. The study subjects were 301 apparently healthy individuals residing in Nagahama City, Japan. Whole blood was collected from each participant when in a non-stimulated state.
Project description:Alzheimer’s disease (AD) is a progressive neurodegenerative disorder with profound global impact. While Genome-wide Association Studies (GWAS) have revealed genomic variants linked to AD, their translational impact has been limited due to challenges in interpreting the identified genetic associations. To address this challenge, we have devised a novel approach termed Transcription Factor-Wide Association Studies (TF-WAS). By integrating the GWAS, eQTL and transcriptome analyses, we selected 30 AD SNPs in non-coding regions that are likely to be functional. Using human transcription factor (TF) microarrays, we have identified 90 allele-specific TF interactions with 53 unique TFs. We then focused on several interactions involving SMAD4, and further validated them using EMSA, luciferase, and ChIP on engineered genetic backgrounds. This approach holds promise for unraveling the intricacies of not just AD, but any complex disease with available GWAS data, providing insight into underlying molecular mechanisms and clues towards potential therapeutic targets.
Project description:Gene expression is regulated by genetic variants and DNA methylation with evidence from molecular biology studies, as well as expression QTL (eQTL) mapping and methylation QTL (mQTL) mapping. In this study, we explored the interaction between genetic variants and DNA methylation for its influence on gene expression. We analyzed a postmortem brain data and identified 2,768 SNP-methylation interaction (SMI) that can survive Bonferroni correction for the number of tests in cis- region of each gene. Seven SNP-methylation pairs were significant after Bonferroni correction for all the tests, including number of gene expression traits, we performed in this study. Only a small proportion of the SMI had evidence from the exact same SNP-transcript pair in eQTL mapping or SNP-methylation pair in mQTL mapping. This suggested that the interaction analysis could uncover novel regulatory relationships, which would be missed by eQTL or mQTL analyses. Since methylation per se is regulated by both genetic and environmental factors, analysis indicates that the SMI detected in this study may involve both genetic and environmental regulation. A total of 155 postmortem cerebellum brains were used in this study, including 47 bipolar disorder, 46 schizophrenia, 15 depression patients and 47 normal controls. All were of European Ancestry. We also designed 13 random replicates in our experiment. Illumina Infinium HumanMethylation27 BeadChip was used for DNA methylation profiling. The assay was performed at the Genomics Core Facility at Northwestern University.