Epigenetic Differences Found between Office Workers and Nickel Smelting Workers

It’s possible that someone’s occupation could have an influence on their epigenetic signature and potentially their well-being. Some people may prefer to work in a steady office environment, some take up graveyard shifts, and others might enjoy working outdoors. All of these occupational settings may have consequences for an individual’s mental and physical health and could result in an alteration of chemical marks that attach to their DNA and impact gene expression.

In hopes of finding relevant biomarkers linked to a particular occupational exposure and related health risks, researchers investigated whether nickel smelting workers had a varied amount of an epigenetic mark in comparison to office workers. Specifically, they looked at the level of a histone modification known as H3K4me3. These results, published in Biomarkers, could help provide an indicator of early health risks and reveal additional information about the biological mechanism of cancer formation. The study also provides interesting insight into how various work environments may impact our epigenome and our health.

Nickel, considered a carcinogen and respiratory irritant, is a metal widely distributed in our environment that can be found in food, soil, water, and air. Workers in the welding and alloy production industries are chronically exposed to this metal and may suffer from diseases such as asthma, chronic bronchitis, reduced lung function, and lung and nasal sinus cancer.

A team of researchers investigated 140 nickel smelting workers and age-matched office workers. They collected blood samples to measure the levels of the histone methylation mark, H3K4me3, and levels of heterochromatin protein 1 (HP1). H3K4me3 is a histone modification associated with gene activation. After isolating histone proteins using EpiGentek’s EpiQuik Total Histone Extraction Kit, the researchers chose to specifically measure global H3K4me3 with an ELISA-like method. To quantify global H3K4me3, they used EpiGentek’s EpiQuik Global Tri-Methyl Histone H3K4 Quantification Kit (Colorimetric).

Overall, the team found that nickel smelting workers had significantly greater H3K4me3 levels compared to the office workers and this epigenetic change was correlated to the length of time workers were employed at the factory. They concluded that chronic exposure to nickel can lead to oxidative damage, increase the expression of H3K4me3 and inhibit the expression of HP1 protein, a major constituent of heterochromatin, which is involved in chromatin structure. It’s understood that euchromatin is less densely packed and therefore accessible to gene transcription whereas heterochromatin is tightly packed and less accessible. Various histone modifications can impact the chromatin structure and influence gene expression. According to the authors, because nickel exposure is associated with increased lung cancer, it’s possible that aberrant H3K4me3 marks may alter chromatin structure and facilitate cancer development.

Research is just beginning to reveal the underlying biological impact on the human body that may occur as a result of our day-to-day work experiences. For example, some of us sit at a desk for extended periods of time. Others, such as painters, mechanics, or welders, are chronically exposed to chemicals associated with their job. As additional research is conducted, preventative measures like adjusting permissible exposure limits or extending office breaks to encourage exercise may become necessary in order to mitigate the negative impacts of a wide range of work environments.

Source: Zhao, Y., Cheng, N., Dai, M., Pu, H., Zheng, T., Li, H., He, J., Bai, Y. (2016). Dynamic variation of histone H3 trimethyl Lys4 (H3K4me3) and heterochromatin protein 1 (HP1) with employment length in nickel smelting workers. Biomarkers.