Rapid DNA methylation changes after exposure to traffic particles
- PMID: 19136372
- PMCID: PMC2720123
- DOI: 10.1164/rccm.200807-1097OC
Rapid DNA methylation changes after exposure to traffic particles
Abstract
Rationale: Exposure to particulate air pollution has been related to increased hospitalization and death, particularly from cardiovascular disease. Lower blood DNA methylation content is found in processes related to cardiovascular outcomes, such as oxidative stress, aging, and atherosclerosis.
Objectives: We evaluated whether particulate pollution modifies DNA methylation in heavily methylated sequences with high representation throughout the human genome.
Methods: We measured DNA methylation of long interspersed nucleotide element (LINE)-1 and Alu repetitive elements by quantitative polymerase chain reaction-pyrosequencing of 1,097 blood samples from 718 elderly participants in the Boston area Normative Aging Study. We used covariate-adjusted mixed models to account for within-subject correlation in repeated measures. We estimated the effects on DNA methylation of ambient particulate pollutants (black carbon, particulate matter with aerodynamic diameter < or = 2.5 microm [PM2.5], or sulfate) in multiple time windows (4 h to 7 d) before the examination. We estimated standardized regression coefficients (beta) expressing the fraction of a standard deviation change in DNA methylation associated with a standard deviation increase in exposure.
Measurements and main results: Repetitive element DNA methylation varied in association with time-related variables, such as day of the week and season. LINE-1 methylation decreased after recent exposure to higher black carbon (beta = -0.11; 95% confidence interval [CI], -0.18 to -0.04; P = 0.002) and PM2.5 (beta = -0.13; 95% CI, -0.19 to -0.06; P < 0.001 for the 7-d moving average). In two-pollutant models, only black carbon, a tracer of traffic particles, was significantly associated with LINE-1 methylation (beta = -0.09; 95% CI, -0.17 to -0.01; P = 0.03). No association was found with Alu methylation (P > 0.12).
Conclusions: We found decreased repeated-element methylation after exposure to traffic particles. Whether decreased methylation mediates exposure-related health effects remains to be determined.
Comment in
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The detrimental health effects of traffic-related air pollution: a role for DNA methylation?Am J Respir Crit Care Med. 2009 Apr 1;179(7):523-4. doi: 10.1164/rccm.200812-1900ED. Am J Respir Crit Care Med. 2009. PMID: 19318540 No abstract available.
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Rapid DNA methylation changes after exposure to traffic particles: the issue of spatio-temporal factors.Am J Respir Crit Care Med. 2009 Nov 15;180(10):1030; author reply 1030-1. doi: 10.1164/ajrccm.180.10.1030. Am J Respir Crit Care Med. 2009. PMID: 19897775 No abstract available.
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