Project description:Childhood asthma is a complex disease historically defined by partially overlapping clinical features, including recurrent respiratory symptoms and reversible airway obstruction. However, the heterogeneity observed in clinical disease and airway pathology suggests that the “traditionally” defined asthma population is composed of multiple subgroups (i.e., endotypes), each with a distinct pathogenesis. Gene expression profiling of bronchial airway brushings identified the type 2-high asthma endotype, defined by excessive airway inflammation driven by type 2 cytokines, which was found in ~50% of subjects. Importantly, response to inhaled corticosteroid treatment was limited to this type 2-high endotype. The clinical utility of type 2-high asthma endotyping and the discovery of other endotypes have been limited by the need to perform an invasive bronchoscopy to obtain the bronchial brushings for analysis. Moreover, research bronchoscopies cannot be performed in children. Less invasive methods for the identification of asthma endotypes are needed. To this end, we found that the type 2-high asthma endotype can be identified by gene expression profiling of minimally invasive nasal airway epithelium brushings. Moreover, we found high nasal expression of the type 2 cytokine, IL-13,4 was associated with higher risk of asthma exacerbations among Puerto Ricans, who have the highest asthma morbidity and mortality in the U.S. Herein, we propose to use whole transcriptome sequencing of nasal airway epithelial brushings from Puerto Rican children with asthma to identify the type 2-high and other asthma endotypes, which relate to severity and drug response.
Project description:Asthma exacerbations in children are associated with respiratory viral infection and atopy, resulting in systemic immune activation and infiltration of immune cells into the airways. The gene networks driving the immune activation and subsequent migration of immune cells into the airways remains incompletely understood. Cellular and molecular profiling of PBMC was employed on paired samples obtained from atopic asthmatic children (n = 19) during acute virus-associated exacerbations and later during convalescence. Systems level analyses were employed to identify coexpression networks and infer the drivers of these networks, and validation was subsequently obtained via independent samples from asthmatic children. During exacerbations, PBMC exhibited significant changes in immune cell abundance and upregulation of complex interlinked networks of coexpressed genes. These were associated with priming of innate immunity, inflammatory and remodelling functions. We identified activation signatures downstream of bacterial LPS, glucocorticoids and TGFB1. We also confirmed that LPS binding protein was upregulated at the protein-level in plasma. Multiple gene networks known to be involved positively or negatively in asthma pathogenesis, are upregulated in circulating PBMC during acute exacerbations, supporting the hypothesis that systemic pre-programming of potentially pathogenic as well as protective functions of circulating immune cells preceeds migration into the airways. Enhanced sensitivity to LPS is likely to modulate the severity of acute asthma exacerbations through exposure to environmental LPS.
Project description:Acute respiratory illness (ARI) is the leading cause of asthma exacerbations yet the mechanisms underlying this association remain unclear. To address the deficiencies in our understanding of the molecular mechanisms driving ARI-induced asthma exacerbations, we undertook a transcriptional profiling study of the nasal mucosa over the course of ARI amongst individuals with a history of asthma, allergic rhinitis and no underlying respiratory disease. We found that ARI is characterized by dynamic, time-specific transcriptional profiles whose magnitudes of expression are influenced by underlying respiratory disease and the mucosal repair signature evoked during ARI. Most strikingly, we report that asthmatics that experience ARI-induced exacerbations are characterized by a reduced but prolonged inflammatory immune response, inadequate activation of mucosal repair and the expression of a newly described exacerbation-specific signature. Findings from our study represent a significant contribution towards clarifying the complex molecular interactions which typify ARI-induced asthma exacerbations. Upon the onset of ‘common cold’, volunteers were instructed to attend the first of three required visits to the study clinic. The first and second visits were designed to obtain samples and clinical data during the early and late stages of symptomatic illness respectively, whereas the third visit would occur when volunteers were asymptomatic and serve as a prospective baseline (BL) for the study.
Project description:Acute respiratory illness (ARI) is the leading cause of asthma exacerbations yet the mechanisms underlying this association remain unclear. To address the deficiencies in our understanding of the molecular mechanisms driving ARI-induced asthma exacerbations, we undertook a transcriptional profiling study of the nasal mucosa over the course of ARI amongst individuals with a history of asthma, allergic rhinitis and no underlying respiratory disease. We found that ARI is characterized by dynamic, time-specific transcriptional profiles whose magnitudes of expression are influenced by underlying respiratory disease and the mucosal repair signature evoked during ARI. Most strikingly, we report that asthmatics that experience ARI-induced exacerbations are characterized by a reduced but prolonged inflammatory immune response, inadequate activation of mucosal repair and the expression of a newly described exacerbation-specific signature. Findings from our study represent a significant contribution towards clarifying the complex molecular interactions which typify ARI-induced asthma exacerbations.
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: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:Rhinovirus infections are the most common cause of asthma exacerbations. The complex responses by the airway epithelium to rhinovirus can be captured by gene expression profiling. We hypothesized that the upper and lower airway epithelium exhibit differential responses to double-stranded RNA (dsRNA), and that this is modulated by the presence of asthma and allergic rhinitis. Identification of dsRNA-induced gene expression profiles by microarray of primary nasal and bronchial epithelial cells from the same individuals and examining the impact of allergic rhinitis with and without concomitant allergic asthma on expression profiles. 17 subjects were included in a cross-sectional study (6 allergic asthma and allergic rhinitis; 5 allergic rhinitis; 6 healthy controls). RNA was extracted from isolated and cultured epithelial cells that were stimulated with Poly(I:C) for 24 hours from bronchial brushes and nasal biopsies, and analyzed by microarray (Affymetrix U133+ PM Genechip Array).
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 )
Project description:A Trial of Mepolizumab Adjunctive Therapy for the Prevention of Asthma Exacerbations in Urban Children (MUPPITS-2). ClinicalTrials.gov Identifier: NCT03292588
Project description:Human bocavirus (HBoV) is a newly discovered parvovirus identified from pooled nasopharyngeal aspirate specimens. Human bocavirus 1 (HBoV1) is a respiratory virus observed in respiratory samples from small children presenting bronchiolitis, wheezing, cough, fever, and rhinorrhea. It is the fourth most common virus detected in respiratory infections. DNA of HBoV1 was detected in up to 18% of nasal or nasopharyngeal samples and another study has been shown that over than 85% of children in the United States have antibodies to this virus. HBoV1 is a small DNA virus with a nonenveloped icosahedral capsid. This virus previously has been associated with wheezing, acute otitis media, severe pneumonia and respiratory failure. HBoV 1 has been also detected in the blood of acute respiratory patients and the selected group of immunocompromised children and also determined in healthy blood donors. The role of HBoV1 in the inflammatory process is poorly known. The aim of this project is to clarify the role of HBOV1 in the immunoregulatory mechanisms.