Project description:This SuperSeries is composed of the following subset Series: GSE34158: Expression data from peripheral blood - blood draws at Pre and Post time points of Allergen inhalation challenge (PAX.GR) GSE34159: Expression data from peripheral blood - blood draws at Pre and Post time points of Allergen inhalation challenge (PAX.NGR) GSE34160: Expression data from peripheral blood - blood draws at Pre and Post time points of Allergen inhalation challenge (PAX.NGR and EDTA) Refer to individual Series
Project description:To determine differential gene expression in peripheral blood of asthmatic individuals undergoing allergen inhalation challenge, post-challenge compared to pre-challenge Blood was collected immediately prior to, and two hours after challenge The 8 PAXgene non-globin reduced (PAX.NGR) samples were combined with 10 EDTA samples (n=9) for one analysis (PAX.NGR+EDTA) comparing gene expression in whole blood between pre and post challenge using the following covariates: tube type, sex, age, PC20 at pre-challenge, and FEV1 after onset and 2h post challenge and the RNA integrity number. Preprocessing and filtering were applied to the PAX.NGR+EDTA dataset using the Factor Analysis for Robust MicroArray Summarization (farms) package in R The Linear Models for MicroArrays (limma) package was used to determine differential gene expression using a Benjamini Hochberg FDR of 5%.
Project description:Background: Allergen inhalation challenge in mild asthmatics induces airflow obstruction, airway hyperresponsiveness and inflammation, providing a model for hypothesis-generating experiments to understand regulation of these responses. We have sought to evaluate the peripheral whole blood transcriptome, post-challenge compared to pre-challenge, and to determine the effect of globin mRNA reduction methodology. Methods: Asthmatic subjects (20-60 years of age, with stable, mild allergic asthma, n=17) underwent allergen inhalation challenges. All subjects had an early asthmatic response of ≥ 20% fall in FEV1; most had a late phase response of ≥ 15% fall in FEV1. Blood was collected immediately prior to, and two hours after allergen challenge. Transcriptome analysis was performed using Affymetrix GeneChip® Human Gene 1.0 ST arrays, with and without globin mRNA reduction (PAX-GR and PAX-NGR, respectively) in 4 subjects. Replication studies for expression of nine genes contributing to the top canonical pathway, Nrf2-mediated oxidative stress response pathway, were performed with 5 independent subjects with microarray data, also with the same 4 subjects had microarray results and 8 other independent subjects with QPCR. Data were analyzed using paired t-test and Partek® Genomics Suite™. Results: The number of differentially expressed probe sets from PAX-NGR samples was twice that of PAX-GR samples. Paired analysis of each subjects' pre- and post-sample additionally demonstrated twice the power to detect differentially expressed probe sets. The Nrf2-mediated oxidative stress response pathway was identified as the top canonical pathway in the PAX-NGR samples. ATP-binding cassette sub-family C member 1 (ABCC1) gene was significantly reduced two hours after allergen challenge in the 5 subjects’ microarray dataset and the 2 QPCR replication datasets with P < 0.05. Conclusions: Globin mRNA reduction does not provide benefits to detect differentially expressed genes during allergen inhalation challenge. Allergen inhalation challenge is associated with decreased peripheral blood cell transcript level of ABCC1 gene. 26 array were analyzed. We first identified differentially expreed genes between post- and pre-challenge samples from 4 asthmatic subjects by using globin reduction samples and non-globin reduction samples (16 arrays). Then we replicated our findings using 10 arrays from 5 asthmatic subjects challenged with allergen. Includes 4 normal blood samples.
Project description:To determine differential gene expression in peripheral blood of asthmatic individuals undergoing allergen inhalation challenge between early responders (ERs) and dual responders (DRs) following allergen inhalation challenge