DNA Methylation and Smoking: Implications for Understanding Effects of Electronic Cigarettes

AbstractPurpose of ReviewUse of electronic cigarettes (e-cigs) has increased sharply recently although understanding of toxicity is limited, particularly target organ effects. Altered DNA methylation is a reversible response to environmental exposures, including smoking, and may be useful as a biomarker of e-cig harm.Recent FindingsAmong studies examining DNA methylation in blood by smoking status, there is considerable variability in differentially methylated CpGs identified; certain CpGs are consistently found. These includeAHRR (aryl hydrocarbon receptor repressor gene), particularly cg05575921, cg0363183 in the F2RL2 gene coding for the protease-activated receptor 4 (PAR-4), and several CpGs in the 2q37.1 genomic region. Differences are found even with short duration and light smoking; effects vary with pack-years and time since quitting among former smokers. For tissues other than blood, data are limited but also indicate altered methylation with smoking.SummaryDNA methylation changes are a consistent biomarker of smoke exposure. Most studies regarding smoke effects on methylation are of blood cells; further evidence regarding effects of smoke, secondhand smoke, and e-cigs on target tissues for smoking-related diseases are needed. Understanding biological effects of e-cigs is critically important to inform regulation; examination of e-cig effects on DNA methylation can significantly add to evidence-based regulation.
Source: Current Epidemiology Reports - Category: Epidemiology Source Type: research