Factory workers' DNA changes when they are at work.

Oct 22, 2008

Tarantini, L, M Bonzini, P Apostoli, V Pegoraro, V Bollati, B Marinelli, L Cantone, G Rizzo, L Hou, J Schwartz, PA Bertazzi and A Baccarelli. 2008. Effects of particulate matter on genomic DNA methylation content and iNOS promoter methylation. Environmental Health Perspectives doi:10.1289/ehp.11898.

Synopsis by Michael D. Laiosa

Factory workers exposed to dust particles have measurable changes in key DNA chemistry on the days they work, but the health impacts are not known.

In a novel study of factory workers in Italy, scientists demonstrate for the first time that a normal chemical change of DNA, called methylation, is decreased on work days but not off days.  Methylation doesn't alter the DNA sequence, but instead is a key part of the control system used to determine when genes are turned on and off.

The authors think the decrease in methylation is caused by regular, elevated exposure to particulate matter in the air. The impacts on workers' health of these specific changes are not known, but changes in methylation are linked to many different diseases.

Identifying the environmental factors that trigger these alarming changes in DNA regulation is the next step.

Methylation acts much like a faucet controlling when and how much water is allowed to flow. If the faucet is abused, it will eventually leak, potentially leading to much bigger problems.

Exposure to particulate matter is linked to numerous adverse health conditions including cardiovascular disease and lung cancer. Remarkably, when the scientists analyzed the amount of DNA methylation found on a specific gene (called inducible Nitric oxide sythnetase or iNOS), they found that it was lower on days the factory workers worked than on days when they were home. Lower methylation of the iNOS DNA would likely mean that more of the iNOS gene was being made, (the faucet is in the open position), possibly promoting an inflammation (a leading risk factor in diseases of the lung and cardiovascular system).

While the authors of the study did not extend their investigation into whether iNOS gene levels were actually affected, the observation that the methylation was lower is indeed a dramatic breakthrough for this field. However, one puzzling aspect of this study is that the changes in iNOS methylation seemed to occur across the board in all the factory workers, not just the ones exposed to particulate matter in their particular work environments. Nevertheless, there are other environmental factors in a factory setting which certainly could be impacting methylation of iNOS DNA.