scholarly journals A Framework for Integrating Directed and Undirected Annotations to Build Explanatory Models of cis-eQTL Data

2019 ◽  
Author(s):  
David Lamparter ◽  
Rajat Bhatnagar ◽  
Katja Hebestreit ◽  
T. Grant Belgard ◽  
Victor Hanson-Smith

1AbstractA longstanding goal of regulatory genetics is to understand how variants in genome sequences lead to changes in gene expression. Here we present a method named Bayesian Annotation Guided eQTL Analysis (BAGEA), a variational Bayes framework to model cis-eQTLs using directed and undirected genomic annotations. In a use case, we integrated directed genomic annotations with eQTL summary statistics from tissues of various origins. This analysis revealed epigenetic marks that are relevant for gene expression in different tissues and cell types. We estimated the predictive power of the models that were fitted based on directed genomic annotations. This analysis showed that, depending on the underlying eQTL data used, the directed genomic annotations could predict up to 1.5% of the variance observed in the expression of genes with top nominal eQTL association p-values < 10−7. For genes with estimated effect sizes in the top 25% quantile, up to 5% of the expression variance could be predicted. Based on our results, we recommend the use of BAGEA for the analysis of cis-eQTL data to reveal annotations relevant to expression biology.

Author(s):  
Nurlan Kerimov ◽  
James D Hayhurst ◽  
Kateryna Peikova ◽  
Jonathan R Manning ◽  
Peter Walter ◽  
...  

An increasing number of gene expression quantitative trait locus (eQTL) studies have made summary statistics publicly available, which can be used to gain insight into complex human traits by downstream analyses, such as fine mapping and colocalisation. However, differences between these datasets, in their variants tested, allele codings, and in the transcriptional features quantified, are a barrier to their widespread use. Consequently, target genes for most GWAS signals have still not been identified. Here, we present the eQTL Catalogue (https://www.ebi.ac.uk/eqtl/), a resource which contains quality controlled, uniformly re-computed QTLs from 21 eQTL studies. We find that for matching cell types and tissues, the eQTL effect sizes are highly reproducible between studies, enabling the integrative analysis of these data. Although most cis-eQTLs were shared between most bulk tissues, the analysis of purified cell types identified a greater diversity of cell-type-specific eQTLs, a subset of which also manifested as novel disease colocalisations. Our summary statistics can be downloaded by FTP, accessed via a REST API, and visualised on the Ensembl genome browser. New datasets will continuously be added to the eQTL Catalogue, enabling the systematic interpretation of human GWAS associations across many cell types and tissues.


2020 ◽  
Author(s):  
Devanshi Patel ◽  
Xiaoling Zhang ◽  
John J. Farrell ◽  
Jaeyoon Chung ◽  
Thor D. Stein ◽  
...  

ABSTRACTBecause regulation of gene expression is heritable and context-dependent, we investigated AD-related gene expression patterns in cell-types in blood and brain. Cis-expression quantitative trait locus (eQTL) mapping was performed genome-wide in blood from 5,257 Framingham Heart Study (FHS) participants and in brain donated by 475 Religious Orders Study/Memory & Aging Project (ROSMAP) participants. The association of gene expression with genotypes for all cis SNPs within 1Mb of genes was evaluated using linear regression models for unrelated subjects and linear mixed models for related subjects. Cell type-specific eQTL (ct-eQTL) models included an interaction term for expression of “proxy” genes that discriminate particular cell type. Ct-eQTL analysis identified 11,649 and 2,533 additional significant gene-SNP eQTL pairs in brain and blood, respectively, that were not detected in generic eQTL analysis. Of note, 386 unique target eGenes of significant eQTLs shared between blood and brain were enriched in apoptosis and Wnt signaling pathways. Five of these shared genes are established AD loci. The potential importance and relevance to AD of significant results in myeloid cell-types is supported by the observation that a large portion of GWS ct-eQTLs map within 1Mb of established AD loci and 58% (23/40) of the most significant eGenes in these eQTLs have previously been implicated in AD. This study identified cell-type specific expression patterns for established and potentially novel AD genes, found additional evidence for the role of myeloid cells in AD risk, and discovered potential novel blood and brain AD biomarkers that highlight the importance of cell-type specific analysis.


Hypertension ◽  
2013 ◽  
Vol 62 (suppl_1) ◽  
Author(s):  
Ko-Ting Lu ◽  
Eric T Weatherford ◽  
Pimonrat Ketsawatsomkron ◽  
Justin L Grobe ◽  
Curt D Sigmund

Expression of the renin gene is required to maintain normal morphological and physiological identity of renal juxtaglomerular (JG) cells, yet the mechanisms regulating renin gene transcription remain elusive. We re-examined data from Brunskill et. al (JASN 22:2213, 2011), investigating genome-wide gene expression in JG and other renal cell types. Based on our previous data implicating nuclear receptors (RAR, RXR, VDR, PPARG, Nr2f2 and Nr2f6) in the regulation of mouse and human renin gene expression, we focused our analysis on the expression of genes encoding the 48 nuclear hormone receptors and their co-regulation with renin. Several nuclear receptors have an expression pattern emulating that of renin, that is, they were similarly enriched in JG cells but not in other cell types. These include Esr1, Nr1h4, Ppara, VDR, Nr1i2, Ppard, Hnf4g, Nr1h3, Thrb, Hnf4a, Esrrg, Nr4a3, Nr3c2, and Ar. We tested the hypothesis that a nuclear receptor that is co-regulated with renin may participate in renin gene regulation. To accomplish this, endogenous renin expression was evaluated in renin-expressing As4.1 cells after siRNA-mediated knock down of selected nuclear receptors. Each experiment included a negative control siRNA duplex (NC) that does not target any known genes. By way of example, siRNA-mediated inhibition of estrogen receptor alpha (Esr1) by 70-80% resulted in a 2-fold decrease in renin mRNA (fold change ± SEM: siEsr1: 0.4±0.2, p<0.001 vs NC). Similar results were obtained with a different siRNA targeting Esr1. Interestingly, loss of Esr1 also caused up-regulation of vitamin D receptor (VDR, 2.8±0.7 fold, p<0.001 vs NC) and Nr2f6 (2.0±0.2 fold, p<0.05 vs NC), both of which are known to be negative regulators of renin. Similarly, both renin (0.1±0.02, p<0.001 vs untreated) and Esr1 (0.3±0.1, p<0.05 vs untreated) mRNA were reduced in the kidney from mice treated with deoxycorticosterone acetate (50mg) and receiving 0.15 M NaCl in drinking water for 21 days (DOCA-salt). These data suggest Esr1 may regulate renin expression. Studies are in progress to assess if Esr1 stimulates renin expression on its own or acts by affecting the level of other nuclear receptors; and to determine if other co-regulated nuclear receptors also regulate expression of the renin gene.


2021 ◽  
Vol 53 (9) ◽  
pp. 1290-1299
Author(s):  
Nurlan Kerimov ◽  
James D. Hayhurst ◽  
Kateryna Peikova ◽  
Jonathan R. Manning ◽  
Peter Walter ◽  
...  

AbstractMany gene expression quantitative trait locus (eQTL) studies have published their summary statistics, which can be used to gain insight into complex human traits by downstream analyses, such as fine mapping and co-localization. However, technical differences between these datasets are a barrier to their widespread use. Consequently, target genes for most genome-wide association study (GWAS) signals have still not been identified. In the present study, we present the eQTL Catalogue (https://www.ebi.ac.uk/eqtl), a resource of quality-controlled, uniformly re-computed gene expression and splicing QTLs from 21 studies. We find that, for matching cell types and tissues, the eQTL effect sizes are highly reproducible between studies. Although most QTLs were shared between most bulk tissues, we identified a greater diversity of cell-type-specific QTLs from purified cell types, a subset of which also manifested as new disease co-localizations. Our summary statistics are freely available to enable the systematic interpretation of human GWAS associations across many cell types and tissues.


2020 ◽  
Vol 31 (10) ◽  
pp. 2326-2340 ◽  
Author(s):  
Yong Li ◽  
Stefan Haug ◽  
Pascal Schlosser ◽  
Alexander Teumer ◽  
Adrienne Tin ◽  
...  

BackgroundGenetic variants identified in genome-wide association studies (GWAS) are often not specific enough to reveal complex underlying physiology. By integrating RNA-seq data and GWAS summary statistics, novel computational methods allow unbiased identification of trait-relevant tissues and cell types.MethodsThe CKDGen consortium provided GWAS summary data for eGFR, urinary albumin-creatinine ratio (UACR), BUN, and serum urate. Genotype-Tissue Expression Project (GTEx) RNA-seq data were used to construct the top 10% specifically expressed genes for each of 53 tissues followed by linkage disequilibrium (LD) score–based enrichment testing for each trait. Similar procedures were performed for five kidney single-cell RNA-seq datasets from humans and mice and for a microdissected tubule RNA-seq dataset from rat. Gene set enrichment analyses were also conducted for genes implicated in Mendelian kidney diseases.ResultsAcross 53 tissues, genes in kidney function–associated GWAS loci were enriched in kidney (P=9.1E-8 for eGFR; P=1.2E-5 for urate) and liver (P=6.8·10-5 for eGFR). In the kidney, proximal tubule was enriched in humans (P=8.5E-5 for eGFR; P=7.8E-6 for urate) and mice (P=0.0003 for eGFR; P=0.0002 for urate) and confirmed as the primary cell type in microdissected tubules and organoids. Gene set enrichment analysis supported this and showed enrichment of genes implicated in monogenic glomerular diseases in podocytes. A systematic approach generated a comprehensive list of GWAS genes prioritized by cell type–specific expression.ConclusionsIntegration of GWAS statistics of kidney function traits and gene expression data identified relevant tissues and cell types, as a basis for further mechanistic studies to understand GWAS loci.


2021 ◽  
Author(s):  
Julien Bryois ◽  
Daniela Calini ◽  
Will Macnair ◽  
Lynette Foo ◽  
Eduard Urich ◽  
...  

Most expression quantitative trait loci (eQTL) studies to date have been performed in heterogeneous brain tissues as opposed to specific cell types. To investigate the genetics of gene expression in adult human cell types from the central nervous system (CNS), we performed an eQTL analysis using single nuclei RNA-seq from 196 individuals in eight CNS cell types. We identified 6108 eGenes, a substantial fraction (43%, 2620 out of 6108) of which show cell-type specific effects, with strongest effects in microglia. Integration of CNS cell-type eQTLs with GWAS revealed novel relationships between expression and disease risk for neuropsychiatric and neurodegenerative diseases. For most GWAS loci, a single gene colocalized in a single cell type providing new clues into disease etiology. Our findings demonstrate substantial contrast in genetic regulation of gene expression among CNS cell types and reveal genetic mechanisms by which disease risk genes influence neurological disorders.


Blood ◽  
2016 ◽  
Vol 128 (22) ◽  
pp. 4283-4283
Author(s):  
Chieh Lee Wong ◽  
Andrew Innes ◽  
Baoshan Ma ◽  
Gareth Gerrard ◽  
Zainul Abidin Norziha ◽  
...  

Abstract Introduction Despite significant progress in the understanding of the molecular pathogenesis of myeloproliferative neoplasms (MPN) and the identification of high molecular risk (HMR) genes (i.e. ASXL1, EZH2, IDH1 and IDH2 genes), the mechanisms by which different cell types predominate in the different disease subtypes and their implications for prognosis remain uncertain. Given the recently described association of senescence and fibrosis in a number of pathologies by Menoz-Espin et al, we hypothesized that genes implicated in oncogene-induced senescence (OIS) and senescence associated secretory phenotype (SASP) may contribute to the pathogenesis of these neoplastic bone marrow disorders that frequently show evidence of fibrosis. Specifically, we were interested in the gene expression levels in different disease subtypes, at a cell-type level, and whether these patterns of differential expression were distinct from the transforming JAK-STAT pathway and the HMR genes. Aim To elucidate the role of OIS and SASP genes in the pathogenesis of MPN subtypes by determining the differential expression of the genes in specific cell types in patients with MPN. Methods We performed gene expression profiling on normal controls (NC) and patients with MPN who were diagnosed with essential thrombocythemia (ET), polycythemia vera (PV) and primary myelofibrosis (PMF) according to the 2008 WHO diagnostic criteria. Two cohorts of patients, the patient and validation cohorts, from 3 tertiary-level hospitals were recruited prospectively over 3 years. Peripheral blood samples were taken and sorted into polymorphonuclear cells (PMN), mononuclear cells (MNC) and T cells. RNA was extracted from each cell population. Gene expression profiling of the human transcriptome was performed using microarray and RNA sequencing on the patient and validation cohorts respectively. Gene expression analyses (GEA) were performed on 4 sets of genes derived from publicly available or custom derived gene set enrichment analysis: 92 OIS genes, 88 SASP genes (Gil et al), 4 HMR genes, and 126 genes associated with JAK-STAT pathway. Gene expression levels for each cell type in each disease were compared with NC to obtain the differential expression of the genes. RNA-seq analysis of samples from the validation cohort was used to validate the microarray results from the patient cohort. Results Twenty-eight patients (10 ET, 11 PV and 7 PMF) and 11 NC were recruited into the patient cohort. Twelve patients (4 ET, 4 PV and 4 PMF) and 4 NC were recruited into the validation cohort. After combination of the microarray and RNA-seq datasets, GEA of the OIS genes revealed the differential expressions of MCTP1 and SULT1B1 genes by PMN in PV but of none in PMF. In contrast, the BEX1 gene was identified as differentially expressed by MNC in PMF but none in PV. GEA of the SASP genes revealed differential expression of THBS1 gene by MNC in PMF but of none in PV. None of the SASP genes were differentially expressed by PMN in either PV or PMF. No differentially expressed genes were identified by PMN or MNC in ET, or by T cells in any of the diseases. Notably, GEA of the HMR genes and genes associated with the JAK-STAT pathways did not show any differential expression in any disease subtype by any cell type. Conclusions We have found strikingly distinct patterns of differential expression of senescence associated genes by PMN (in PV) and MNC (in PMF). These results provide a novel insight into the mechanisms underlying the different phenotype of the MPN subtypes and also to the cells responsible for mediating the differences. The lack of differential expression of OIS and SASP genes in ET may reflect the milder clinical phenotype of the disease. Although mutations in the HMR genes are associated with poor prognosis in PMF, the lack of differential expression in these genes and genes associated with the JAK-STAT pathway is in keeping with their mutated status and suggests that they give rise to the disease phenotypes via altering downstream expression of genes associated in other pathways such as the senescence pathways studied here. Further studies are warranted to investigate the role of these genes and the pathways involved in senescence at a cell-type specific level in order to gain further insight into how they can potentially give rise to the various disease phenotypes in MPN and unmask potential therapeutic targets. Disclosures Aitman: Illumina: Honoraria.


Cells ◽  
2021 ◽  
Vol 10 (9) ◽  
pp. 2395
Author(s):  
Tobias Strunz ◽  
Martin Kellner ◽  
Christina Kiel ◽  
Bernhard H. F. Weber

Elucidating the role of genetic variation in the regulation of gene expression is key to understanding the pathobiology of complex diseases which, in consequence, is crucial in devising targeted treatment options. Expression quantitative trait locus (eQTL) analysis correlates a genetic variant with the strength of gene expression, thus defining thousands of regulated genes in a multitude of human cell types and tissues. Some eQTL may not act independently of each other but instead may be regulated in a coordinated fashion by seemingly independent genetic variants. To address this issue, we combined the approaches of eQTL analysis and colocalization studies. Gene expression was determined in datasets comprising 49 tissues from the Genotype-Tissue Expression (GTEx) project. From about 33,000 regulated genes, over 14,000 were found to be co-regulated in pairs and were assembled across all tissues to almost 15,000 unique clusters containing up to nine regulated genes affected by the same eQTL signal. The distance of co-regulated eGenes was, on average, 112 kilobase pairs. Of 713 genes known to express clinical symptoms upon haploinsufficiency, 231 (32.4%) are part of at least one of the identified clusters. This calls for caution should treatment approaches aim at an upregulation of a haploinsufficient gene. In conclusion, we present an unbiased approach to identifying co-regulated genes in and across multiple tissues. Knowledge of such common effects is crucial to appreciate implications on biological pathways involved, specifically when a treatment option targets a co-regulated disease gene.


2019 ◽  
Vol 31 (3) ◽  
pp. 496 ◽  
Author(s):  
Iside Scaravaggi ◽  
Nicole Borel ◽  
Rebekka Romer ◽  
Isabel Imboden ◽  
Susanne E. Ulbrich ◽  
...  

Previous endometrial gene expression studies during the time of conceptus migration did not provide final conclusions on the mechanisms of maternal recognition of pregnancy (MRP) in the mare. This called for a cell type-specific endometrial gene expression analysis in response to embryo signals to improve the understanding of gene expression regulation in the context of MRP. Laser capture microdissection was used to collect luminal epithelium (LE), glandular epithelium and stroma from endometrial biopsies from Day 12 of pregnancy and Day 12 of the oestrous cycle. RNA sequencing (RNA-Seq) showed greater expression differences between cell types than between pregnant and cyclic states; differences between the pregnant and cyclic states were mainly found in LE. Comparison with a previous RNA-Seq dataset for whole biopsy samples revealed the specific origin of gene expression differences. Furthermore, genes specifically differentially expressed (DE) in one cell type were found that were not detectable as DE in biopsies. Overall, this study revealed spatial information about endometrial gene expression during the phase of initial MRP. The conceptus induced changes in the expression of genes involved in blood vessel development, specific spatial regulation of the immune system, growth factors, regulation of prostaglandin synthesis, transport prostaglandin receptors, specifically prostaglandin F receptor (PTGFR) in the context of prevention of luteolysis.


2009 ◽  
Vol 29 (10) ◽  
pp. 2794-2803 ◽  
Author(s):  
Xiaoling Wang ◽  
Meenalakshmi Chinnam ◽  
Jianmin Wang ◽  
Yanqing Wang ◽  
Xiaojing Zhang ◽  
...  

ABSTRACT Accumulating evidence suggests that regulation of RNA processing through an RNP-driven mechanism is important for coordinated gene expression. This hypothesis predicts that defects in RNP biogenesis will adversely affect the elaboration of specific gene expression programs. To explore the role of RNP biogenesis on mammalian development, we have characterized the phenotype of mice hypomorphic for Thoc1. Thoc1 encodes an essential component of the evolutionarily conserved TREX complex. TREX accompanies the elongating RNA polymerase II and facilitates RNP assembly and recruitment of RNA processing factors. Hypomorphic Thoc1 mice are viable despite significantly reduced Thoc1 expression in the tissues examined. While most tissues of Thoc1-deficient mice appear to develop and function normally, gametogenesis is severely compromised. Male infertility is associated with a loss in spermatocyte viability and abnormal endocrine signaling. We suggest that loss of spermatocyte viability is a consequence of defects in the expression of genes required for normal differentiation of cell types within the testes. A number of the genes affected appear to be direct targets for regulation by Thoc1. These findings support the notion that Thoc1-mediated RNP assembly contributes to the coordinated expression of genes necessary for normal differentiation and development in vivo.


Sign in / Sign up

Export Citation Format

Share Document