Genomics and the respiratory effects of air pollution exposure

Adverse health effects from air pollutants remain important, despite improvement in air quality in the past few decades. The exact mechanisms of lung injury from exposure to air pollutants are not yet fully understood. Studying the genome (e.g. single nucleotide polymorphisms, SNPs), epigenome (e.g. methylation of genes), transcriptome (mRNA expression) and microRNAome (microRNA expression) has the potential to improve our understanding of the adverse effects of air pollutants. Genome-wide association studies of SNPs have detected SNPs associated with respiratory phenotypes; however, to date, only candidate gene studies of air pollution exposure have been performed. Changes in epigenetic processes, such DNA methylation which leads to gene silencing without altering the DNA sequence, occur with air pollutant exposure, especially global and gene-specific methylation changes. Respiratory cell line and animal models demonstrate distinct gene expression signatures in the transcriptome, arising from exposure to particulate matter or ozone. Particulate matter and other environmental toxins alter expression of microRNAs, which are short non-coding RNAs that regulate gene expression. While it is clearly important to contain rising levels of air pollution, strategies also need to be developed to minimise the damaging effects of air pollutant exposure on the lung, especially for patients with chronic lung disease and for people at-risk of future lung disease. Careful study of genomic responses will improve our understanding of mechanisms of lung injury from air pollution and enable future clinical testing of interventions against the toxic effects of air pollutants