The nasal methylome as a biomarker of asthma and airway inflammation in children.
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ABSTRACT:
SUBMITTER: Cardenas A
PROVIDER: S-EPMC6625976 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:BackgroundGiven the strong environmental influence on both epigenetic marks and allergic asthma in children, the epigenetic alterations in respiratory epithelia might provide insight into allergic asthma.ObjectiveWe sought to identify DNA methylation and gene expression changes associated with childhood allergic persistent asthma.MethodsWe compared genomic DNA methylation patterns and gene expression in African American children with persistent atopic asthma (n = 36) versus healthy control subjects (n = 36). Results were validated in an independent population of asthmatic children (n = 30) by using a shared healthy control population (n = 36) and in an independent population of white adult atopic asthmatic patients (n = 12) and control subjects (n = 12).ResultsWe identified 186 genes with significant methylation changes, differentially methylated regions or differentially methylated probes, after adjustment for age, sex, race/ethnicity, batch effects, inflation, and multiple comparisons. Genes differentially methylated included those with established roles in asthma and atopy and genes related to extracellular matrix, immunity, cell adhesion, epigenetic regulation, and airflow obstruction. The methylation changes were substantial (median, 9.5%; range, 2.6% to 29.5%). Hypomethylated and hypermethylated genes were associated with increased and decreased gene expression, respectively (P < 2.8 × 10-6 for differentially methylated regions and P < 7.8 × 10-10 for differentially methylated probes). Quantitative analysis in 53 differentially expressed genes demonstrated that 32 (60%) have significant methylation-expression relationships within 5 kb of the gene. Ten loci selected based on the relevance to asthma, magnitude of methylation change, and methylation-expression relationships were validated in an independent cohort of children with atopic asthma. Sixty-seven of 186 genes also have significant asthma-associated methylation changes in nasal epithelia of adult white asthmatic patients.ConclusionsEpigenetic marks in respiratory epithelia are associated with allergic asthma and gene expression changes in inner-city children.
| S-EPMC5391298 | biostudies-literature
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: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.
2015-11-01 | GSE65163 | GEO
Project description:BackgroundIt has been established that patients with chronic rhinosinusitis with nasal polyps (CRSwNP) often have co-existing asthma.ObjectiveWe aimed to test two hypotheses: (i) upper and lower airway inflammation in CRSwNP is uniform in agreement with the united airways concept; and (ii) bronchial inflammation exists in all CRSwNP patients irrespective of clinical asthma status.MethodsWe collected biopsies from nasal polyps, inferior turbinates and bronchi of 27 CRSwNP patients and 6 controls. All participants were evaluated for lower airway disease according to international guidelines. Inflammatory cytokines were investigated using a Th1/Th2 assay including 14 chemokines and cytokines; tissue concentrations were normalized according to tissue weight and total protein concentration. Individual cytokines and multivariate inflammatory profiles were compared between biopsy sites and between patients and controls.ResultsWe found significantly higher concentrations of Th2 cytokines in nasal polyps compared to inferior turbinate and bronchial biopsies. In addition, we showed that the inflammatory profile of nasal polyps and bronchial biopsies correlated significantly (p<0.01). From the Th2 cytokines measured, IL-13 was significantly increased in bronchial biopsies from CRSwNP patients with, but not without asthma.ConclusionOur findings support the united airways concept; however, we did not find evidence for subclinical bronchial inflammation in CRSwNP patients without asthma. Finally, this study indicates for the first time that nasal polyps potentially play an important role in the airway inflammation rather than being a secondary phenomenon.
| S-EPMC4489400 | biostudies-literature
Project description:In asthma, the relationship among airway inflammation, airway hyperresponsiveness, and lung function is poorly understood. Methods to noninvasively assess these relationships in human subjects are needed. We sought to determine whether (18)F-FDG uptake rate (K(i), min(-1)) could serve as a biomarker of eosinophilic inflammation and local lung function.We used PET/CT to assess regional pulmonary perfusion (Q), specific ventilation per unit volume (sV(A)), fractional gas content (Fgas), airway wall thickness, and regional K(i) 10 h after segmental allergen challenge to the right middle lobe in 6 asthmatic subjects with demonstrated atopy. Q, sV(A), and Fgas in the allergen-challenged lobe were compared with the right upper lobe, where diluent was applied as a control. The airway wall thickness aspect ratio (?) of the allergen-challenged airway was compared with those of similarly sized airways from unaffected areas of the lung. Differences in K(i) between allergen and diluent segments were compared with those in cell counts obtained 24 h after the allergen challenge by a bronchoalveolar lavage of the respective segments.We found systematic reductions in regional Q, sV(A), and Fgas and increased ? in all subjects. The ratio of eosinophil count (allergen to diluent) was linearly related (R(2) = 0.9917, P < 0.001) to the ratio of K(i).Regional K(i) measured with PET is a noninvasive and highly predictive biomarker of eosinophilic airway inflammation and its functional effects. This method may serve to help in the understanding of allergic inflammation and test the therapeutic effectiveness of novel drugs or treatments.
| S-EPMC3855676 | biostudies-literature
Project description:Noneosinophilic asthma is common across asthma severities. However, in patients with moderate-to-severe disease, the absence of sputum eosinophilia cannot distinguish between asthmatic subjects with eosinophilic inflammation controlled by corticosteroids versus those in whom eosinophilic inflammation is not a component of the disease.We sought to develop a method to quantify eosinophil proteins in airway macrophages as a novel biomarker of eosinophilic airway inflammation.Eosinophil proteins in airway macrophages were assessed by means of flow cytometry, immunofluorescence, and cytoplasmic hue change after ingestion of apoptotic eosinophils. Airway macrophage median percentage of red-hued area in stained sputum cytospin preparations was assessed by means of image analysis from (1) subjects with mild-to-severe asthma, subjects with nonasthmatic eosinophilic bronchitis, and healthy control subjects; (2) subjects with eosinophilic severe asthma after treatment with prednisolone; and (3) subject with noneosinophilic asthma before corticosteroid withdrawal.Eosinophil proteins were detected in airway macrophages, and cytoplasmic red hue increased after ingestion of apoptotic eosinophils. Airway macrophage percentage redhued area was increased in subjects with moderate-to-severe asthma compared with that seen in subjects with mild asthma and healthy control subjects, was similar in those with or without a sputum eosinophilia, and was increased after corticosteroid therapy. In asthmatic subjects without sputum eosinophilia, the airway macrophage percentage red-hued area was increased in subjects who did versus those who did not have sputum eosinophilia after corticosteroid withdrawal.Eosinophil proteins can be reliably measured in airway macrophages. In combination with sputum eosinophilia, the macrophage eosinophil protein content might further define the asthma phenotype and provide an additional tool to direct therapy.
| S-EPMC3992372 | biostudies-literature
Project description:AimsTo examine whether asthma induced by exposure to aluminium potroom emissions (potroom asthma) is associated with inflammatory changes in the airways.MethodsBronchial biopsy specimens from 20 asthmatic workers (8 non-smokers and 12 smokers), 15 healthy workers (8 non-smokers and 7 smokers), and 10 non-exposed controls (all non-smokers) were analysed. Immunohistofluorescent staining was performed to identify mucosal total leucocytes (CD45+ leucocytes), neutrophils, and mast cells.ResultsMedian RBM thickness was significantly increased in both asthmatic workers (8.2 microm) and healthy workers (7.4 microm) compared to non-exposed controls (6.7 microm). Non-smoking asthmatic workers had significantly increased median density of lamina propria CD45+ leucocytes (1519 cells/mm2 v 660 and 887 cells/mm2) and eosinophils (27 cells/mm2 v 10 and 3 cells/mm2) and significantly increased concentrations of exhaled NO (18.1 ppb v 6.5 and 5.1 ppb) compared to non-smoking healthy workers and non-exposed controls. Leucocyte counts and exhaled NO concentrations varied with smoking habits and fewer leucocytes were observed in asthmatic smokers than in non-smokers Asthmatic smokers had significantly increased numbers of eosinophils in lamina propria compared to non-exposed controls (10 v 3 cells/mm2). Both eosinophilic and non-eosinophilic phenotypes of asthma were recognised in the potroom workers and signs of airway inflammation were also observed in healthy workers.ConclusionsAirway inflammation is a central feature of potroom asthma and exposure to potroom emissions induces pathological alterations similar to those described in other types of asthma. Cigarette smoking seems to affect the underlying mechanisms involved in asthma, as the cellular composition of airway mucosa appears different in asthmatic smokers and non-smokers.
| S-EPMC1763667 | biostudies-literature
Project description:BACKGROUND: Asthma is an inflammatory disease of the airways, but in clinical practice inflammation is rarely monitored. The aim of this study was to assess the level of airway inflammation in steroid naïve adult and pediatric patients with intermittent asthma over one year. METHODS: 54 children and 50 adults with intermittent asthma (GINA step 1) were included. On up to 6 visits lung function, airway hyperresponsiveness to methacholine (PC20FEV1), sputum eosinophils and exhaled nitric oxide (FeNO) were assessed. RESULTS: 36 pediatric and 34 adult patients were able to produce at least three adequate sputum samples over the study period and were included into the analysis.In 8 children (22%) the percentage of sputum eosinophils was always below 2.5%. A higher level of eosinophils (>2.5%) was found on at least one visit in 16 (44%) and always >2.5% in 12 children (33%). In the adult group the respective numbers were 14 patients (41%) with always low (<2.5%), 17 (50%) with at least once over 2.5% and three patients (9%) were always above the threshold of 2.5% sputum eosinophils. CONCLUSION: These results demonstrate that a substantial number of children and adults with intermittent asthma under ß-agonist treatment only, have variable or persistently high levels of eosinophilic airway inflammation. Long-term studies are needed to observe the progression of asthma severity in such patient populations.
| S-EPMC4301900 | biostudies-other
Project description:This SuperSeries is composed of the SubSeries listed below.
2017-10-02 | GSE104472 | GEO
Project description:IntroductionInnate immune activation through exposure to indoor and outdoor pollutants is emerging as an important determinant of asthma severity. For example, household levels of the bacterial product lipopolysaccharide (LPS) are associated with increased asthma severity. We hypothesized that activation of the innate immune receptor TLR5 by its bacterial ligand flagellin will exacerbate airway inflammation and asthma symptoms.MethodsWe determined the effect of flagellin co-exposure with ovalbumin in a murine model of allergic asthma. We evaluated the presence of flagellin activity in house dust of asthma patients. Finally, we analyzed the association of a dominant-negative polymorphism in TLR5 (rs5744168) with asthma symptoms in patients with asthma.ResultsWe showed that bacterial flagellin can be found in the house dust of patients with asthma and that this bacterial product exacerbates allergic airway inflammation in an allergen-specific mouse model of asthma. Furthermore, a dominant-negative genetic polymorphism in TLR5, the receptor for flagellin, is associated with decreased symptoms in patients with asthma.ConclusionTogether, our results reveal a novel genetic protective factor (TLR5 deficiency) and a novel environmental pollutant (microbial flagellin) that influence asthma severity. (Clinical trials NCT01688986 and NCT01087307).
| S-EPMC7123460 | biostudies-literature