Project description:<p>The purpose of this study is to discover in vivo cytokine expression quantitative trait locus (eQTL) interactions from a cohort of patients with systemic lupus erythematosus. 157 lupus patients were enrolled in a clinical trial to test the efficacy and safety of an anti-IL-6 monoclonal antibody. At three time points, we measured interferon (IFN) status, anti-IL-6 drug exposure and genome-wide gen expression. We identified 4,818 cis-eQTLs and then observed a statistically significant enrichment of in vivo eQTL interactions with IFN status and anti-IL-6 exposure.</p>
Project description:Background: Cytokines are critical to human disease and are attractive therapeutic targets given their widespread influence on gene regulation and transcription. Defining the downstream regulatory mechanisms influenced by cytokines is central to defining drug and disease mechanisms. One promising strategy is to use interactions between expression quantitative trait loci (eQTLs) and cytokine levels to define target genes and mechanisms. Results: In a clinical trial for anti-IL-6 in patients with systemic lupus erythematosus we measured interferon (IFN) status, anti-IL-6 drug exposure and whole blood genome-wide gene expression at three time points (379 samples from 157 individuals). First, we show that repeat transcriptomic measurements increases the number of cis eQTLs identified compared to using a single time point by 64%. Then, after identifying 4,818 cis-eQTLs, we observed a statistically significant enrichment of in vivo eQTL interactions with IFN status (p<0.001 by permutation) and anti-IL-6 drug exposure (p<0.001). We observed 210 and 72 interactions for IFN and anti-IL-6 respectively (FDR<20%). Anti-IL-6 interactions have not yet been described while 99 of the IFN interactions are novel. Finally, we found transcription factor binding motifs interrupted by eQTL interaction SNPs, pointing to key regulatory mediators of these environmental stimuli and therefore potential therapeutic targets for autoimmune diseases. In particular, genes with IFN interactions are enriched for ISRE binding site motifs, while those with anti-IL-6 interactions are enriched for IRF4 motifs. Conclusion: This study highlights the potential to exploit clinical trial data to discover in vivo eQTL interactions with therapeutically relevant environmental variables.
Project description:GeneSet variation analysis was performed on microarrays to study the transcriptome of microdissected renal biopsies from lupus nephritis patients.
Project description:To screen specific DNA methylation markers in systemic lupus erythematosus (SLE) patient's blood DNA, whole-blood DNAs from 6 female SLE patients and 6 female controls were analyzed by methylation microarray.
Project description:Systemic lupus erythematosus (SLE) is a chronic-relapsing autoimmune disease of incompletely understood etiology. Recent evidence strongly supports an epigenetic contribution to the pathogenesis of lupus. To understand the extent and nature of dysregulated DNA methylation in lupus T cells, we performed a genome-wide DNA methylation study in CD4+ T cells from 12 lupus patients and 12 normal healthy controls. Cytosine methylation was quantified in 27,578 CG pairs located within the promoter regions of 14,495 genes. We identified 236 hypomethylated and 105 hypermethylated CG sites in lupus CD4+ T cells compared to normal controls, consistent with a global hypomethylation in lupus T cells. Further analysis identified hypomethylation in genes involved in connective tissue development including CD9, MMP9, and PDGFRA. Hypermethylated genes highlight “response to nutrients” ontology such as folate biosynthesis, suggesting a link between environmental factor and lupus and emphasizing the role of folate in DNA methylation. In addition, the transcription factor RUNX3 was hypermethylated in lupus CD4+ T cells. Protein-protein interaction maps identified a transcription factor, HNF4a, as a regulatory hub affecting a number of differentially methylated genes. Functional annotations such as apoptosis is also overrepresented. Further, our data indicate that the methylation status of certain genes predicts disease activity in lupus patients. This work provides a foundation to begin identifying novel pathogenic pathways in lupus T cells and developing novel epigenetic biomarkers for disease activity in lupus. We employed microarray-based technologies to perform a genome-wide DNA methylation assay and quantify CD4+ T cell DNA methylation levels at 27,578 CG sites spanning 14,495 genes of 11 lupus patients and 12 healthy controls.
Project description:Systemic lupus erythematosus (SLE) is a chronic-relapsing autoimmune disease of incompletely understood etiology. Recent evidence strongly supports an epigenetic contribution to the pathogenesis of lupus. To understand the extent and nature of dysregulated DNA methylation in lupus T cells, we performed a genome-wide DNA methylation study in CD4+ T cells from 12 lupus patients and 12 normal healthy controls. Cytosine methylation was quantified in 27,578 CG pairs located within the promoter regions of 14,495 genes. We identified 236 hypomethylated and 105 hypermethylated CG sites in lupus CD4+ T cells compared to normal controls, consistent with a global hypomethylation in lupus T cells. Further analysis identified hypomethylation in genes involved in connective tissue development including CD9, MMP9, and PDGFRA. Hypermethylated genes highlight “response to nutrients” ontology such as folate biosynthesis, suggesting a link between environmental factor and lupus and emphasizing the role of folate in DNA methylation. In addition, the transcription factor RUNX3 was hypermethylated in lupus CD4+ T cells. Protein-protein interaction maps identified a transcription factor, HNF4a, as a regulatory hub affecting a number of differentially methylated genes. Functional annotations such as apoptosis is also overrepresented. Further, our data indicate that the methylation status of certain genes predicts disease activity in lupus patients. This work provides a foundation to begin identifying novel pathogenic pathways in lupus T cells and developing novel epigenetic biomarkers for disease activity in lupus.
Project description:Aberrant gene expression analysis between peripheral blood mononuclear cells (PBMCs) samples from healthy controls (HC) and patients with systemic lupus erythmatosus (SLE) were identified using Affymetrix gene arrays
Project description:In this study we use RNAseq to explore allele specific expression (ASE) in adipose tissue of male and female F1 mice, produced from reciprocal crosses of C57BL/6J and DBA/2J strains. Comparison of the identified cis-eQTLs, to local-eQTLs, that were obtained from adipose tissue expression in two previous population based studies in our laboratory, yields poor overlap between the two mapping approaches, while both local-eQTL studies show highly concordant results. Specifically, local-eQTL studies show ~60% overlap between themselves, while only 15-20% of local-eQTLs are identified as cis by ASE, and less than 50% of ASE genes are recovered in local-eQTL studies. Utilizing recently published ENCODE data, we also find that ASE genes show significant bias for SNPs prevalence in DNase I hypersensitive sites that is ASE direction specific. We suggest a new approach to analysis of allele specific expression that is more sensitive and accurate than the commonly used fisher or chi-square statistics. Our analysis indicates that technical differences between the cis and local-eQTL approaches, such as differences in genomic background or sex specificity, account for relatively small fraction of the discrepancy. Therefore, we suggest that the differences between two eQTL mapping approaches may facilitate sorting of SNP-eQTL interactions into true cis and trans, and that a considerable portion of local-eQTL may actually represent trans interactions.