Project description:Asthma is an inflammatory disease of the airways characterised by episodic airway obstruction resulting in cough, episodic shortness of breath. It is, and is clinically and physiologically heterogeneous. It is estimated that around 300 million people worldwide have the diseaseare diagnosed with asthma, including up to 20% of children (Asher et al, 2006), with 5–10% of these children believed to have severe or difficult-to-treat asthma. Asthma has often been classified in terms of severity and based on clinical diagnostic criteria, but it is now apparent that the heterogeneity that exists at the physiological level is also a feature of the underlying pathological mechanisms (Lotvall et al, 2011). The aim of this study was to identify blood transcriptomics profiles for children diagnosed with asthma or wheeze, and establish whether these profiles suggested endotypes or mechanisms that could underlie disease, or be related to disease severity, in these children. Importantly, given that children are currently treated with the same medicines as adults, we also aimed to compare profiles of children to those of adults with asthma to help determine whether efforts should be directed to the development of medicines targeting pathways and mechanisms that may be unique to children. To this end, we used gene transcriptome data generated from blood samples from adults and children from the U-BIOPRED consortium to ask how similar or different the differential gene expression profiles were between groups of adults and pre-school or school-aged children with severe or mild-moderate asthma (or wheeze for the pre-school aged children) using current definitions. The Unbiased Biomarkers for the Prediction of Respiratory Disease Outcomes (U-BIOPRED) project was set up as a public-private partnership within the framework of the Innovative Medicines Initiative (IMI), engaging academia, the pharmaceutical industry and patient groups. The goal of this investigation was to identify transcript fingerprints in whole blood that characterize patients with severe asthma and to determine whether subgroups of severe asthmatics can be identified.
Project description:Severe asthma is a collection of disease entities with varying pathophysiological characteristics (7) that result in symptoms of cough, wheeze and breathlessness, with frequent exacerbations. To address the problem of phenotypic difference and heterogeneity, the Unbiased Biomarkers for the Prediction of Respiratory Disease Outcomes (U-BIOPRED) project was set up as a public-private partnership within the framework of the Innovative Medicines Initiative (IMI), engaging academia, the pharmaceutical industry and patient groups. The goal of this investigation was to identify transcript fingerprints in whole blood that characterize patients with severe asthma and to determine whether subgroups of severe asthmatics can be identified. Furthermore, we were interested in elucidating the biological pathways that showed differences between subgroups.
Project description:Asthma and postinfectious bronchiolitis obliterans (PIBO) are chronic lung diseases characterized by recurrent episodes of wheezing. Mycoplasma, adenovirus, and respiratory syncytial virus infections can trigger both asthma and PIBO. These two diseases have common etiologic mechanisms that cause airway epithelial injury. They are often difficult to differentiate clinically in preschool children because both are exacerbated by viral infections and respond similarly to steroids and β2 agonists. PIBO, which is occasionally observed in children, is diagnosed through characteristic findings of air trapping on computed tomography or in biopsy samples of lung tissue. However, researchers have not clearly identified the specific blood markers that can distinguish these diseases or the differences in the mechanisms of development. We performed proteomic analysis of plasma to identify specific biomarkers that can be helpful in differentiating asthma from PIBO. This study discovered plasma biomarker candidates by measuring plasma proteome sequential window acquisition of all theoretical mass spectra (SWATH-MS) and included 30 healthy children, 18 with asthma and 15 with PIBO. was used to measure proteins in plasma samples. We identified and quantified 354 proteins across all 63 samples in the SWATH-MS analysis.
Project description:Rationale: MicroRNAs have emerged as crucial post-transcriptional and network regulators in inflammatory diseases, including asthma. We hypothesized that peripheral blood miRNA would be associated with airflow obstruction in children with asthma, and that some of these effects would also be observable in adults with COPD. Methods: We analyzed small RNA-Seq data from 365 peripheral blood samples from the Genetics of Asthma in Costa Rica Study (GACRS). GACRS comprised children from the Central Valley of Costa Rica age 6-14 years with physician-diagnosed asthma and ≥2 respiratory symptoms or asthma attacks in the prior year. FEV1/FVC percent-predicted was dichotomized at 100%, splitting the cohort into those with and without evidence of airflow obstruction and used as our primary outcome. Differentially expressed (DE) miRs were identified using the DESeq2 package in R with a 10% FDR and adjustment for age, gender, and inhaled corticosteroid (ICS) use. We attempted to replicate the top airflow obstruction-associated microRNAs from the GACRS study in the COPDGene study, in which blood microRNA data were available in 439 current and former smoking adults with and without airflow obstruction (defined as raw FEV1/FVC < 0.7). Results: After QC, we had 361 samples and 649 miRs for DE analysis. Of the 361 samples, 220 and 141 were from subjects without and with airflow obstruction, respectively. We found 1 upregulated (let-7e-5p p=0.0004) and 2 downregulated (miR-342-3p p=0.0002; miR-671-5p p=0.0001) miRs in subjects with airflow obstruction compared to those without airflow obstruction. These three miRNAs were then tested for association with airflow obstruction in the COPDGene study, in which let-7e-5p was upregulated (p = 0.064) and miR-342-3p (p =0.085) was downregulated in participants with FEV1/FVC < 0.7 (n=196) compared to those with FEV1/FVC > 0.7 (n=243). Differentially expressed miR’s target genes were enriched for PI3K-Akt, Hippo, WNT, MAPK, and focal adhesion signaling pathways. We also separately considered the targets of only the two miRNAs that were also associated with FEV1/FVC in the adult current and former smokers, where PI3K-Akt, MAPK and Hippo signaling pathways were among the top five most enriched pathways. Conclusion: Three DE miRs were linked to airflow obstruction in children with asthma. Two miRs were associated with FEV1/FVC in current and former smoking adults. These miRs were involved in asthma and COPD-related pathways: PI3K-Akt, Hippo, MAPK, and focal adhesion signaling pathways. Together these findings provide important evidence that these two disorders may share genetic regulatory systems that contribute to airflow obstruction.
Project description:The objective of this study was to identify gene expression markers of disease severity in a cohort of RSV infected children Respiratory syncytial virus (RSV) is the number one pathogen causing lower respiratory tract infection that leads to hospitalization in young children. Despite growing insights in the disease pathogenesis, the clinical presentation in these children is highly variable and heterogeneous, and reliable markers predictive of disease progression are lacking. We characterized the host response to acute RSV infection to identify biomarkers associated with RSV disease and disease severity. Whole genome transcriptome was analysed early on the disease course in blood samples from otherwise healthy children <2 years of age, who were either hospitalized (n = 110) or evaluated as outpatients (n = 37) due to RSV infection. Age-matched non-RSV-infected healthy children (n = 51) were analysed in parallel. A clustering approach on the transcriptome data revealed biologically meaningful biomarkers associated with progression to severe RSV disease. Overall, the whole blood transcriptome pointed to alterations in frequency of specific immune cell types (neutrophils, T- and B-lymphocytes, NK cells, monocytes) in RSV-infected children. In addition, a cluster enriched for neutrophil degranulation genes, was highly correlated with clinical disease severity. The driver genes of this cluster (OLFM4, ELANE, MMP8, BPI, CEACAM8, LCN2, LTF and MPO) were selected and validated in independent existing transcriptomics datasets. We identified a set of genes involved in neutrophil degranulation as markers for RSV disease severity. Additional prospective studies using these markers are required to further confirm their value as predictive tool in routine clinical care.
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.
Project description:Background: Asthma is highly heterogeneous and severity evaluation is key to asthma management. DNA methylation (DNAm) contributes to asthma pathogenesis. This study aimed to identify nasal epithelial DNAm differences between severe and non-severe asthmatic children and evaluate the impact of environmental exposures. Methods: Thirty-three non-severe and 22 severe asthmatic African-American children were included in an epigenome-wide association study. Genome-wide nasal epithelial DNAm and gene expression were measured. CpG sites associated with asthma severity and environmental exposures and predictive of severe asthma were identified. DNAm was correlated with gene expression. Enrichment for transcription factor (TF) binding sites or histone modifications surrounding DNAm differences were determined. Results: We identified 816 differentially methylated CpG positions (DMPs) and 10 differentially methylated regions (DMRs) associated with asthma severity. Three DMPs exhibited discriminatory ability for severe asthma. Intriguingly, six DMPs were simultaneously associated with asthma, allergic asthma, total IgE, environmental IgE, and FeNO in an independent cohort of children. 27 DMPs were associated with traffic-related air pollution or secondhand smoke. DNAm at 22 DMPs were altered by diesel particles or allergen in human bronchial epithelial cells. DNAm levels at 39 DMPs were correlated with mRNA expression. Proximal to 816 DMPs, three histone marks and several TFs involved in asthma pathogenesis were enriched. Conclusions: Significant differences in nasal epithelial DNAm were observed between non-severe and severe asthma in African-American children, a subset of which may be useful to predict disease severity. These CpG sites are subject to the influences of environmental exposures and may regulate gene expression.
Project description:Nasal swab specimens were collected from children who presented to the emergency department with an acute exacerbation of asthma or wheeze. Samples were also collected from control subjects. Convalescent/quiescent samples were collected from children who were followed-up at least 6 weeks after an acute exacerbation of asthma or wheeze. Gene expression was profiled on microarrays.