Air pollution exposure is associated with gene expression in children

Environmental exposures, including air pollutants and lack of natural spaces, are associated with suboptimal health outcomes in children. We aimed to study the associations between environmental exposures and gene expression in children. Associations of exposure to particulate matter with diameter < 2.5 (PM2.5) and < 10 (PM10) micrometers, nitrogen dioxide, green spaces, and blue space, with whole blood gene expression were explored in children from the Dutch Generation R Study (n=172). Analyses were adjusted for age, sex, batch, maternal education, and area socioeconomic status. Follow-up analysis was carried out using lymphoblastoid cell line gene expression in children from the ALSPAC Study (n=946). Gene set enrichment analysis using hallmark and immune gene sets from the molecular signature database was carried out to identify significantly over-represented gene sets for insights into biological mechanisms. Exposure to PM2.5 was associated with expression of 86 genes in discovery analyses in the Generation R Study (false discovery rate-adjusted p-value < 0.25). Of these, PM2.5 was also associated with GNG11 expression in the same direction in follow-up analysis (false discovery rate-adjusted p-value < 0.05). The remaining exposures showed much fewer associations in the discovery analyses. Gene set enrichment analysis using PM2.5 association results for both cohorts indicated suppression of gene sets related to interferon response and response to bacterial and viral exposure. In conclusion, gene expression analysis performed in two independent cohorts, suggests that PM2.5 exposure in children may be involved in interferon and microbial infection responses.