Air pollution on epigenetics
Ambient air pollution can originate from burning of fossil fuels related to traffic and energy production. This leads to the generation of noxious gases such as nitrogen oxide and the formation of fine particles. Accumulating evidence indicates that exposure to polluted air is associated with cardiovascular diseases and increases the risk for lung cancer at the population level. Although the precise mechanism underlying the harmful effect of PM on health is not fully understood, oxidative damage on cellular structures are emerging as possible mechanisms. Scientists on the EU-funded EPIGENAIR (Epigenomic markers for air pollution-induced health effects) project set out to investigate the possibility that PM causes gene expression changes by interfering with the epigenetic machinery. Epidemiological studies suggest that particulate air pollution affects global and gene-specific DNA methylation. The EPIGENAIR consortium analysed DNA methylation data in relation to estimates of exposure to air pollutants. They used a methylation array, which assessed methylation levels of more than 480 000 loci across the genome. Air pollution was estimated via land-use regression models. Results showed that increased exposure to nitrous oxides was associated with decreased and aberrant global DNA methylation patterns. Intriguingly, analysis of children samples from the Avon Longitudinal Study of Parents and Children (ALSPAC) demonstrated a similar pattern in cord blood of new-borns and, in blood from children of age 15. However, in seven-year-old children this pattern was reversed. Close inspection of the affected DNA regions suggested that methylation changes following exposure to air pollution might not be extremely stable. Collectively, the findings of the EPIGENAIR study provide fundamental insight into the molecular impact of air pollution. Given that DNA methylation protects the genome and low methylation can cause genome instability, these results underscore the importance of air pollution in cancer development.
Keywords
Air pollution, epigenetics, particulate matter, nitrogen oxide, lung cancer, DNA methylation
