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: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.
Project description:Allergic sensitisation and reduced ability to respond to viral infections may contribute to virus-induced wheeze and asthma development in young children. Plasmacytoid dendritic cells (pDC) are rare immune cells that produce type I interferons (IFN-I) and play a key role in orchestrating immune responses against viruses. To further evaluate the function of pDC in children with asthma, we studied a subset of 71 children from the Early Life Lung Function (ELLF) cohort at the age of 7-years. As part of the ELLF study, participants were characterised for atopic sensitisation, viral infection history and lung function testing. pDC responses to a TLR7/8 agonist were assessed in the presence or absence of anti-IgE using an in vitro assay. Responses were evaluated utilising flow cytometry, multiplexed cytokine assays and transcriptional analysis of isolated pDC. pDC responses varied considerably across individuals and those who responded with IFN-I following stimulation showed lower proportion of asthma compared to those who responded with TNF-only. A TNF-only response was associated with increased atopy and reduced upregulation of IFN-associated genes. Anti-IgE stimulation reduced pDC activation and the reduction was associated with baseline expression of the IgE receptor (FceR1). A reduction in a gene module centralised around genes such as TPM2, LILRA4 and CLEC4C was also observed. Together, these findings suggest that pDC responses are variable, associated with asthma and appear influenced by environmental stimuli. This response thus appears to be an important aspect of asthma pathology in children.
Project description:Background Impaired interferon response and allergic sensitisation may contribute to virus induced wheeze and asthma development in young children. Plasmacytoid dendritic cells (pDC) play a key role in antiviral immunity as critical producers of type I interferons (IFN-I). pDC also express the high affinity IgE receptor (FcRI) through which IFN-I production may be negatively regulated. If antiviral function of pDC is associated with recurrent episodes of wheeze in young children is not well understood. This study aimed to evaluate the phenotype and function of circulating pDC in children with a longitudinally defined wheezing phenotype. Methods We performed multiparameter flow cytometry on peripheral blood mononuclear cells from 38 children presenting to the emergency department with an acute episode of respiratory wheeze and 19 controls. RNA sequencing on isolated pDC from the same individuals was also performed. For each subject, their longitudinal exacerbation phenotype was determined using the Western Australia public hospital database. Results We observed a significant depletion of circulating pDC in young children with a persistent phenotype of wheeze. The same individuals also displayed upregulation of the IgE receptor (FcRI) on their pDC. Based on transcriptomic analysis, pDC from these individuals did not mount a robust systemic antiviral response as observed in children who displayed a non-recurrent wheezing phenotype. Conclusion Our data suggests that circulating pDC phenotype and function are altered in young children with a persistent longitudinal exacerbation phenotype. Expression of FcRI is increased and their function as major IFN producers is impaired during acute exacerbations of wheeze.
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:Obesity is a risk factor for asthma severity and morbidity, displaying a distinct clinical phenotype that is less responsive to inhaled corticosteroids. CD4+ T-cells are central to the immunologic pathways of asthma and may contribute to the unique obese asthma phenotype. We sought to characterize the single cell CD4+ transcriptional profile among obese children with asthma compared to matched normal weight children with asthma.
Project description:Our study aimed to better understand the immune responses during an acute asthma exacerbation in children. Gene expression profiles were examined by RNA-sequencing in blood samples. Samples were collected on average 2.5 day after systemic corticosteroid treatment. Our findings show that pro-inflammatory genes and pathways related to innate responses and signaling remained increased in children hospitalized for acute asthma exacerbation. Genes and pathways involved in adaptive immune respones, particularly T lymphocyte activation, were decreased in children hospitalized for acute asthma exacerbation. These studies suggest that innate immune responses may remain activated following hospitalization for asthma exacerbation.
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: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.