Background B lymphocytes play important roles in the inflammatory response in asthma including IgE production, antigen presentation and secretion of certain cytokines. However the exact molecular pathways are still largely unknown. The objectives of this study were to identify gene expression profiles of peripheral blood B lymphocytes and subsequently determine gene signatures that were associated with different clinical phenotypes of asthma. In addition we aimed to identify biological processes and pathways involved in the molecular mechanisms of asthma.
Method Peripheral blood B cells were isolated from subjects with different manifestations of asthma: mild (n=8), moderate controlled (n=8), moderate uncontrolled (n=10), severe steroid dependant (n=7), severe steroid resistant (n=7) and normal control (n=8). Total RNA were extracted from the B lymphocytes, reverse transcribed and amplified linearly before being labelled and hybridized on Illumina HumanRef-8 Expression BeadChips that had 24,355 elements. Microarray data was analysed using GeneSpring GX 10.0.02 software and real-time PCR was performed to validate the microarray gene expression.
Results Data were analysed according to several conditions including asthma control status, steroid response, asthma severity and disease status. Differential gene analyses, corrected for multiple testing, revealed 7 (p<0.001), 307 (p<0.001), 52 (p<0.01) and 40 (p<0.05) genes that were differentially expressed in each condition respectively. Those genes were found to be involved in various biological processes including T lymphocyte and mast cell activation, cytoskeleton actin regulation, Notch pathway and guanylate cyclase pathway when analysed using the gene set enrichment analysis (GSEA). Several gene signatures like CCT6A, TUBGCP3, RARRES2, PSIP1 and SLC38A6 that were found to be associated with asthma control status and response to steroid.
Conclusion These findings may provide new insight in the mechanisms of airway inflammation in asthma.