Identification of differences in CD4+ T-cell gene expression between people with asthma and healthy controls

Background: Functional enrichment analysis of genome-wide association study (GWAS)-summary statistics has suggested that immune cell-types, and especially CD4+ T-cells, play an important role in asthma pathogenesis. Despite this, CD4+ T-cells are under-represented in asthma transcriptome studies. Objective: To identify differences in gene expression between asthmatics and healthy controls in CD4+ T-cells. Methods: CD4+ T-cells were isolated within 2 hours from collection from peripheral blood from people with well-established asthma (n=33) and healthy controls (n=12). 3'-RNA-Seq was used to generate gene expression data. Weighted Gene Co-expression Network Analysis (WGCNA) was used to identify sets of co-expressed genes (modules). The asthma-associated modules were tested for enrichment of GWAS-identified asthma genes and gene ontology (GO) biological processes. For the genes in the asthma-associated modules, integration of eQTL and GWAS summary statistics (colocalisation), and protein-protein interaction (PPI) data was used to identify master regulators. Results: After quality control, 43 samples were available for the analysis. WGCNA identified three modules associated with asthma, which are strongly enriched for GWAS-identified asthma genes, antigen processing/presentation and immune response to viral infections. Colocalisation analysis of eQTL and GWAS summary statistics, together with PPI data, identified PTPRC as a master regulator of asthma gene-expression profiles in CD4+ T-cells. Conclusion: Unstimulated CD4+ T-cells from peripheral blood from asthmatics have different expression profiles, compared to healthy controls, for sets of genes involved in immune response to viral infections and antigen processing/presentation . Integration of genetic and protein-protein interaction data identified PTPRC as a master regulator of genes in asthma. 3'UTR RNA-seq from CD4+ T cell from asthmatics and healthy controls