Airway epithelial gene expression in asthma versus healthy controls
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ABSTRACT: Airway epithelial brushings were obtained for microarray analysis by research bronchoscopy in 62 subjects with mild-to-moderate asthma not on inhaled steroids and 43 healthy controls. Asthma subjects were stratified into 2 subgroups, Th2 high and Th2 low asthma, based on their expression of a three-gene signature of Type 2 inflammation: POSTN, SERPINB2, and CLCA1.
Project description:Airway epithelial brushings were obtained for microarray analysis by research bronchoscopy in 62 subjects with mild-to-moderate asthma not on inhaled steroids and 43 healthy controls. Asthma subjects were stratified into 2 subgroups, Th2 high and Th2 low asthma, based on their expression of a three-gene signature of Type 2 inflammation: POSTN, SERPINB2, and CLCA1. Gene expression comparisons were made between: 1. asthmatics and healthy controls, and 2. Th2 high asthma and Th2 Low asthma/Healthy controls. The gene expression alterations most associated with asthma were then used in gene set enrichment analyses and gene signature development to compare this asthma dataset to COPD gene expression datasets.
Project description:Bronchial epithelial brushings were obtained by bronchoscopy from 8 steroid-naïve asthmatics including type 2-low (n=4) and type 2-high asthma (n=4), and 4 healthy controls. The type 2-low and –high asthma was defined by the epithelial expression of a three-gene signature for type 2 status (POSTN, SERPINB2, and CLCA1).
Project description:To better understand the therapeutic potential of targeting Th2 inflammation in asthma, we performed genome-wide expression profiling of endobronchial biopsies in asthmatics and healthy controls stratified according a previously defined three-gene Th2 signature in bronchial epithelium. The Th2 signature is defined as relatively high expression of POSTN, CLCA1, and SERPINB2.
Project description:Molecular profiling studies in asthma cohorts have identified a Th2-driven asthma subtype, characterized by elevated lower airway expression of POSTN, CLCA1 and SERPINB2. To assess upper airway gene expression as a potential biomarker for lower airway Th2 inflammation, we assayed upper airway (nasal) and lower airway (bronchial) epithelial gene expression, serum total IgE, blood eosinophils and serum periostin in a cohort of 54 allergic asthmatics and 30 matched healthy controls. 23 of 51 asthmatics in our cohort were classified as âTh2 highâ based on lower airway Th2 gene signature expression. Consistent with this classification, âTh2 highâ subjects displayed elevated total IgE and blood eosinophil levels relative to âTh2 lowâ subjects. Upper airway Th2 signature expression was significantly correlated with lower airway Th2 signature expression (r=0.44), with similar strength of association as serum total IgE and blood eosinophils, known biomarkers of Th2 inflammation. In an unbiased genome-wide scan, we identified 8 upper airway genes more strongly correlated with lower airway Th2 gene signature expression (r=0.58), including Eotaxin-3 (CCL26), Galectin-10 (CLC) and Cathepsin-C (CTSC). Asthmatics classified as âTh2 highâ using this 8-gene signature show similar serum total IgE and blood eosinophil levels as âTh2 highâ asthmatics classified using lower airway Th2 gene signature expression. We have identified an 8-gene upper airway signature correlated with lower airway Th2 inflammation, which may be used as a diagnostic biomarker for Th2-driven asthma. Upper airway (nasal) and lower airway (bronchial) epithelial brushings obtained from a cohort of 54 allergic asthmatics and 30 matched healthy controls were profiled by gene expression by microarray. Subjects were assayed for gene expression, serum total IgE, blood eosinophils and serum periostin.
Project description:Molecular profiling studies in asthma cohorts have identified a Th2-driven asthma subtype, characterized by elevated lower airway expression of POSTN, CLCA1 and SERPINB2. To assess upper airway gene expression as a potential biomarker for lower airway Th2 inflammation, we assayed upper airway (nasal) and lower airway (bronchial) epithelial gene expression, serum total IgE, blood eosinophils and serum periostin in a cohort of 54 allergic asthmatics and 30 matched healthy controls. 23 of 51 asthmatics in our cohort were classified as ‘Th2 high’ based on lower airway Th2 gene signature expression. Consistent with this classification, ‘Th2 high’ subjects displayed elevated total IgE and blood eosinophil levels relative to ‘Th2 low’ subjects. Upper airway Th2 signature expression was significantly correlated with lower airway Th2 signature expression (r=0.44), with similar strength of association as serum total IgE and blood eosinophils, known biomarkers of Th2 inflammation. In an unbiased genome-wide scan, we identified 8 upper airway genes more strongly correlated with lower airway Th2 gene signature expression (r=0.58), including Eotaxin-3 (CCL26), Galectin-10 (CLC) and Cathepsin-C (CTSC). Asthmatics classified as ‘Th2 high’ using this 8-gene signature show similar serum total IgE and blood eosinophil levels as ‘Th2 high’ asthmatics classified using lower airway Th2 gene signature expression. We have identified an 8-gene upper airway signature correlated with lower airway Th2 inflammation, which may be used as a diagnostic biomarker for Th2-driven asthma.
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:We performed small RNA sequencing (TruSeq) of gene expression on bronchial cells from human bronchial epithelial brushings from 16 independent subjects whose samples were classified as either healthy controls (with no asthma or lung disease) or steroid-naive asthmatics (subjects with asthma not using inhaled corticosteroids (ICS) for 6 weeks before enrollment that were studied at baseline ('Steroid-naive asthma - Baseline') or after 8 weeks of treatment with budesonide, 200 μg twice a day, ('Steroid-naive asthma - Post-ICS treatment')). The goal was to assess abundance of miRNAs in all the samples collectively.
Project description:This protocol outlines a single-site mechanistic study aiming to investigate long RNAs differentially expressed in the airway epithelium of asthma patients both at baseline and in response to segmental airway allergen challenges. Over approximately 14 days, the study spanned three visits: Visit 1: Comprehensive characterization of participants, encompassing lung function testing, methacholine challenge testing, and allergen skin prick testing. Visit 2: Participants underwent bronchoscopy wherein three procedures were performed a. Epithelial brushings were performed in a segmental airway (baseline sample) b. Diluent (inactive control) was instilled into another segmental airway c. A small dose of allergen was administered into a third segmental airway using standardized cat or dust mite allergen extracts. Visit 3 (24 hours or 7 days post Visit 2): Another bronchoscopy was carried out to collect epithelial brushings in the diluent challenged and allergen challenged segments The collected epithelial brush samples underwent analysis for mRNA expression in the epithelial brushings. The study successfully incorporated a total of 23 subjects, which included 18 asthmatics (with stable or well-controlled conditions), 2 allergic non-asthmatics, and 3 non-allergic non-asthmatics.
Project description:Allergic asthma and rhinitis are two common chronic allergic diseases that affect the lungs and nose, respectively. Both diseases share clinical and pathological features characteristic of excessive allergen-induced type 2 inflammation, orchestrated by memory CD4+ T cells that produce type 2 cytokines (TH2 cells). However, a large majority of subjects with allergic rhinitis do not develop asthma, suggesting divergence in disease mechanisms. Since TH2 cells play a pathogenic role in both these diseases and are also present in healthy non-allergic subjects, we performed global transcriptional profiling to determine whether there are qualitative differences in TH2 cells from subjects with allergic asthma, rhinitis and healthy controls. TH2 cells from asthmatic subjects expressed higher levels of several genes that promote their survival as well as alter their metabolic pathways to favor persistence at sites of allergic inflammation. In addition, genes that enhanced TH2 polarization and TH2 cytokine production were also upregulated in asthma. Several genes that oppose T cell activation were downregulated in asthma, suggesting enhanced activation potential of TH2 cells from asthmatic subjects. Many novel genes with poorly defined functions were also differentially expressed in asthma. Thus, our transcriptomic analysis of circulating TH2 cells has identified several molecules that are likely to confer pathogenic features to TH2 cells that are either unique or common to both asthma and rhinitis.
Project description:Asthma is a chronic inflammatory disease of the airways driven by complex genetic-environmental interactions. Epigenomic mechanisms including histone modifications and DNA methylation are altered in key cell types of asthma. However, genome-wide studies of histone modifications in the airway epithelium of asthmatics have yet to be undertaken. We undertook genome-wide profiling of an enhancer (regulatory domain)-associated histone modification H3K27ac in bronchial epithelial cells (BECs) from asthmatic and healthy control individuals. We identified 49,903 (P<0.05) regions exhibiting differential H3K27ac enrichment in asthma and found they clustered predominately at genes associated with Th2-high asthma (e.g. CLCA1) and epithelial processes (e.g. EMT). We determined asthma had a dramatic influence on the enhancer landscape of BECs and identified asthma-associated Super-Enhancers encompassing genes encoding transcription factors (e.g. TP63) and enzymes involved in lipid metabolism (e.g. NOX4). We integrated published protein expression, epigenomic and transcriptomic datasets and identified epithelium-specific transcription factors associated with H3K27ac in asthma (e.g. TP73) and dynamic relationships between asthma-associated changes in H3K27ac, DNA methylation, genetic susceptibility and transcriptional profiles. Finally, using a CRISPR-based approach to recapitulate the H3K27ac landscape of asthma in vitro, we provide proof of principal that asthma-associated gene expression (e.g. SERPINB2) is driven in part by aberrant histone acetylation. This report identifies the influence of asthma on the epigenome of airway epithelium and provides evidence that aberrant epigenomic mechanisms exert functional consequences in key cell types of asthma, validating the combination of genome-wide and epigenome-editing approaches in identifying and deciphering the molecular mechanisms underlying asthma pathogenesis.