Pooled genome-wide analysis to identify novel risk loci for pediatric allergic asthma
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ABSTRACT:
ORGANISM(S): Homo sapiens
PROVIDER: GSE24481 | GEO | 2011/03/17
SECONDARY ACCESSION(S): PRJNA132513
REPOSITORIES: GEO
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Project description:We performed a pooled GWAS and individual genotyping in 269 children with allergic respiratory diseases comparing allergic children with and without asthma. We used a modular approach to identify the most significant loci associated with asthma by combining silhouette statistics and physical distance method with cluster-adapted thresholding. We found 97% concordance between pooled GWAS and individual genotyping, with 36 out of 37 top-scoring SNPs significant at individual genotyping level. The most significant SNP is located inside the coding sequence of C5, an already identified asthma susceptibility gene, while the other loci regulate functions that are relevant to bronchial physiopathology, as immune- or inflammation-mediated mechanisms and airway smooth muscle contraction. Integration with gene expression data (from mouse experimental asthma model taken from GSE6858 and GSE1301) showed that almost half of the putative susceptibility genes are differentially expressed in experimental asthma mouse models. Affymetrix SNP arrays (Mapping 250K NspI and StyI) were performed according to the manufacturer's directions on pooled DNA extracted from peripheral blood samples.The design is a pooled-GWAS. DNA samples were assigned to the Asthma group if displaying symptoms of asthma, alone or associated to other allergic phenotypes, including rhinoconjunctivitis (RC), and assigned to the RC group if displaying rhinitis or rhinoconjunctivits alone or associated to other allergic phenotypes, excluding asthma. Each of the two groups was subdiveded into 4 independent groups of samples, each containing 31-36 individuals. Individual DNA samples were then added to their respective pools in equivalent molar amounts. Each pool was labeled and hybridized independently on three different arrays (3 technical replicates for each pool).
2011-03-17 | E-GEOD-24481 | biostudies-arrayexpress
Project description:Background: Asthma is the most common chronic disease in children with an increasing prevalence in recent years. Its development depends on genetic and environmental factors and allergic sensitization is a known trigger. Dog allergens affect up to 30% of all children and dog dander-sensitized children show increased expression of cystatin-1 (CST1) and eotaxin-3 (CCL26). The aim of our study was to investigate the functional mechanism of CST1 and CCL26 in the alveolar basal epithelial cell line A549. Methods: A549 cells were transfected with individual overexpression vectors for CST1 and CCL26 and RNA sequencing was performed to examine the transcriptomics. DESeq2 was used to identify differentially expressed genes (= DEG) and ShinyGO v0.77 and Enrichr for pathway enrichment analysis. Results: The overexpression of CST1 resulted in a total of 23 DEG (3 upregulated and 20 downregulated) and the overexpression of CCL26 in a total of 113 DEG (3 upregulated and 110 downregulated). The gene ontology enrichment analysis showed a significant downregulation of type I and III interferon signaling pathway genes as well as interferon-stimulated genes. Conclusion: Our results indicate that an overexpression of CST1 and especially CCL26 cause a downregulation of interferon related genes. It might cause a higher disease susceptibility, mainly for allergic asthma, as CCL26 is an agonist for CCR-3-carrying cells, such as eosinophils and Th2 lymphocytes, mostly active in allergic asthma.
2024-01-19 | GSE229741 | GEO
Project description:Recent genome-wide association studies (GWAS) have identified a number of novel genetic associations with complex human diseases. In spite of these successes, results from GWAS generally explain only a small proportion of disease heritability, an observation termed the M-bM-^@M-^\missing heritability problem.M-bM-^@M-^] Several sources for the missing heritability have been proposed, including the contribution of many common variants with small individual effect sizes, which cannot be reliably found using the standard GWAS approach. The goal of our study was to explore a complementary approach, which combines GWAS results with functional data in order to identify novel genetic associations with small effect sizes. To do so, we conducted a GWAS for lymphocyte count, a physiologic quantitative trait associated with asthma, in 462 Hutterites. In parallel, we performed a genome-wide gene expression study in lymphoblastoid cell lines (LCLs) from 96 Hutterites. We found significant support for genetic associations using the GWAS data when we considered variants near the 193 genes whose expression levels across individuals were most correlated with lymphocyte counts. Interestingly, these variants are also enriched with signatures of an association with asthma susceptibility, an observation we were able to replicate. The associated loci include genes previously implicated in asthma susceptibility, as well as novel candidate genes enriched for functions related to T cell receptor signaling and ATP synthesis. Our results, therefore, establish a new set of asthma susceptibility candidate genes. More generally, our observations support the notion that many loci of small effects influence variation in lymphocyte count and asthma susceptibility. 96 RNA samples were collected (1 subsequently excluded) from lymphoblastoid cell lines derived from Hutterite subjects chosen to represent the extremes of absolute lymphocyte count. The high and low absolute lymphocyte count groups were balanced with respect to age, gender, and relatedness.
2012-02-01 | E-GEOD-30697 | biostudies-arrayexpress
Project description:Recent genome-wide association studies (GWAS) have identified a number of novel genetic associations with complex human diseases. In spite of these successes, results from GWAS generally explain only a small proportion of disease heritability, an observation termed the “missing heritability problem.” Several sources for the missing heritability have been proposed, including the contribution of many common variants with small individual effect sizes, which cannot be reliably found using the standard GWAS approach. The goal of our study was to explore a complementary approach, which combines GWAS results with functional data in order to identify novel genetic associations with small effect sizes. To do so, we conducted a GWAS for lymphocyte count, a physiologic quantitative trait associated with asthma, in 462 Hutterites. In parallel, we performed a genome-wide gene expression study in lymphoblastoid cell lines (LCLs) from 96 Hutterites. We found significant support for genetic associations using the GWAS data when we considered variants near the 193 genes whose expression levels across individuals were most correlated with lymphocyte counts. Interestingly, these variants are also enriched with signatures of an association with asthma susceptibility, an observation we were able to replicate. The associated loci include genes previously implicated in asthma susceptibility, as well as novel candidate genes enriched for functions related to T cell receptor signaling and ATP synthesis. Our results, therefore, establish a new set of asthma susceptibility candidate genes. More generally, our observations support the notion that many loci of small effects influence variation in lymphocyte count and asthma susceptibility.
2012-02-01 | GSE30697 | GEO
Project description:Background: In asthma, airway epithelium remodeling can already be detected during childhood, and epithelial cells are more susceptible to virus and oxidative stress. Their exact role in natural history and severity of children allergic respiratory disease remains however surprisingly unexplored. Aim: To analyze dysfunctions of epithelium in dust mite allergic respiratory disease (rhinitis ± asthma) in children. Methods: Expression profilings of nasal epithelial cells collected by brushing were performed on Affymetrix Hugene 1.0 ST arrays. All allergic patients were sensitized to dust mite. 19 patients had an isolated allergic rhinitis (AR). 14 patients had AR associated with asthma. Patients were compared to 12 controls, their severity and control being assessed according to NAEPP and ARIA criteria. Infections by respiratory viruses were excluded by real-time PCR measurements. Results: 61 probes were able to distinguish allergic rhinitis children from healthy controls. A majority of these probes was under the control of Th2 cytokines, as evidenced by parallel experiments performed on primary cultures of nasal epithelial cells. In uncontrolled asthmatic patients, we observed not only an enhanced expression of these Th2-responsive transcripts, but also a down-regulation of interferon-responsive genes. Conclusion: Our study identifies a Th2 driven epithelial phenotype common to all dust mite allergic children. Besides, it suggests that epithelium is involved in the severity of the disease. Expression profiles observed in uncontrolled asthmatic patients suggest that severity of asthma is linked at the same time to atopy and to impaired viral response. Nasal epithelium gene expression profiling of dust mite allergic children with isolated rhinitis, rhinitis associated with asthma and controls. 38 samples classified in 4 categories : 14 isolated rhinitis (R), 6 rhinitis with uncontrolled asthma (UA), 7 rhinitis with controlled asthma (CA) and 11 healthy subjects (C )
2012-01-05 | E-GEOD-19187 | biostudies-arrayexpress
Project description:In the first decade of life, high-asthma risk urban children develop stable phenotypes of respiratory health versus disease that link early life environmental exposures to childhood allergic sensitization and asthma. Moreover, unique patterns of nasal gene expression demonstrate how specific molecular pathways underlie distinct respiratory phenotypes, including allergic and non-allergic asthma.
2021-04-01 | GSE145505 | GEO
Project description:Background: Nasal epithelia are emerging as a proxy measure of gene expression of the airway epithelium in asthma. We hypothesized that epigenetic marks regulate gene expression of the nasal epithelia and consequently may provide a novel target for allergic asthma. Methods: We compared genomic DNA methylation patterns and gene expression in African American children with persistent atopic asthma [N=36] versus healthy controls [N=36]. Results were validated in an independent population of asthmatics [N=30]. Results: We identified 186 genes with significant methylation changes, either as regions (differentially methylated regions [DMRs]) or single CpGs (differentially methylated probes [DMPs]) after adjustment for age, gender, race/ethnicity, batch effects, inflation, and multiple comparisons (false discovery rate-adjusted q<0.05). Genes differentially methylated include those with established roles in asthma and atopy, components of the extracellular matrix, genes related to immunity, cell adhesion, epigenetic regulation, and airway obstruction. The methylation changes are large (median 9.5%, range: 2.6-29.5% methylation change) and similar in magnitude to those observed in malignancies. Hypo- and hyper-methylated genes were associated with increased and decreased gene expression respectively (P<2.8x10-6 for DMRs and P<7.8x10-10 for DMPs). Quantitative analysis of methylation-expression relationships in 53 differentially expressed genes demonstrated that 32 (60%) have significant (q<0.05) methylation-expression relationships within 5kb of the gene. 10 loci selected based on the relevance to asthma, magnitude of methylation change, and asthma specific methylation-expression relationships were validated in an independent cohort of children with asthma. Conclusions: Our findings that epigenetic marks in respiratory epithelia are associated with allergic asthma in inner-city children provide new targets for biomarker development, and novel approaches to understanding disease pathogenesis. case control design with nasal epithelial cells from 36 atopic asthmatic and 36 nonatopic nonasthmatic children from the inner city
2015-11-01 | E-GEOD-65163 | biostudies-arrayexpress
Project description:To gain insight into the promoting effect of ultrafine particle inhalation on development and progression of allergic asthma, we selected an experimental approach involving exposure to ultrafine carbon particles (UCP) and gene expression profiling of lungs from mice with experimental, ovalbumin induced allergy. Comparative gene expression analysis was performed by hybridizing pooled cDNA samples from lavaged lungs of different groups. The results suggest that allergic sensitization may represent an susceptibility factor for effects of UCP on gene expression in the lung. In sensitized individuals UCP exposure, such as found in polluted air, thus may contribute to the development and/or aggrevation of allergic asthma. Keywords: Particle Inhalation, lung, ovalbumin sensitized and challanged, expression profling
2007-07-01 | GSE6571 | GEO
Project description:To gain insight into the promoting effect of ultrafine particle inhalation on development and progression of allergic asthma, we selected an experimental approach involving exposure to ultrafine carbon particles (UCP) and gene expression profiling of lungs from mice with experimental, ovalbumin induced allergy. Comparative gene expression analysis was performed by hybridizing pooled cDNA samples from lavaged lungs of different groups. These results suggest that allergic sensitization may represent a susceptibility factor for effects of UCP on gene expression in the lung. In sensitized individuals UCP exposure, such as found in polluted air, thus may contribute to the development and /or aggravation of allergic asthma. Keywords: Particle Inhalation, lung, ovalbumin sensitzed and challanged, experssion profiling
2007-07-01 | GSE6496 | GEO
Project description:Background: In asthma, airway epithelium remodeling can already be detected during childhood, and epithelial cells are more susceptible to virus and oxidative stress. Their exact role in natural history and severity of children allergic respiratory disease remains however surprisingly unexplored. Aim: To analyze dysfunctions of epithelium in dust mite allergic respiratory disease (rhinitis ± asthma) in children. Methods: Expression profilings of nasal epithelial cells collected by brushing were performed on Affymetrix Hugene 1.0 ST arrays. All allergic patients were sensitized to dust mite. 19 patients had an isolated allergic rhinitis (AR). 14 patients had AR associated with asthma. Patients were compared to 12 controls, their severity and control being assessed according to NAEPP and ARIA criteria. Infections by respiratory viruses were excluded by real-time PCR measurements. Results: 61 probes were able to distinguish allergic rhinitis children from healthy controls. A majority of these probes was under the control of Th2 cytokines, as evidenced by parallel experiments performed on primary cultures of nasal epithelial cells. In uncontrolled asthmatic patients, we observed not only an enhanced expression of these Th2-responsive transcripts, but also a down-regulation of interferon-responsive genes. Conclusion: Our study identifies a Th2 driven epithelial phenotype common to all dust mite allergic children. Besides, it suggests that epithelium is involved in the severity of the disease. Expression profiles observed in uncontrolled asthmatic patients suggest that severity of asthma is linked at the same time to atopy and to impaired viral response. Nasal epithelium gene expression profiling of dust mite allergic children with isolated rhinitis, rhinitis associated with asthma and controls.
2012-01-05 | GSE19187 | GEO