Inhalable Metal-Rich Air Particles and Histone H3K4 Dimethylation and H3K9 Acetylation in a Cross-sectional Study of Steel Workers

• Published in: Environmental health perspectives Vol. 119; no. 7; pp. 964 - 969
• Main Authors: Cantone, Laura, Nordio, Francesco, Hou, Lifang, Apostoli, Pietro, Bonzini, Matteo, Tarantini, Letizia, Angelici, Laura, Bollati, Valentina, Zanobetti, Antonella, Schwartz, Joel, Bertazzi, Pier A., Baccarelli, Andrea
• Format: Journal Article
• Language: English
• Published: Research Triangle Park, NC National Institute of Environmental Health Sciences 01.07.2011; US Department of Health and Human Services
• Subjects: Acetylation; Adult; Air Pollutants - adverse effects; Aluminum; Arsenic; Biological and medical sciences; Blood; Carcinogenesis, carcinogens and anticarcinogens; Chemical agents; Chemical and industrial products toxicology. Toxic occupational diseases; Chemical hazards; Cross-Sectional Studies; Employment; Environment. Living conditions; Environmental health; Epigenesis, Genetic; Gene expression; Histones; Histones - blood; Histones - chemistry; Histones - genetics; Histones - metabolism; Humans; Iron; Italy; Lead; Leukocytes; Leukocytes - chemistry; Lung cancer; Lysine; Male; Manganese; Medical sciences; Metallurgy; Metals - analysis; Metals and various inorganic compounds; Methylation; Middle Aged; Nickel; Occupational Exposure; Particulate Matter - analysis; Physiological aspects; Protein Processing, Post-Translational; Public health. Hygiene; Public health. Hygiene-occupational medicine; Risk factors; Steels; Toxicology; Tumors; Zinc; Italy; United States; Modification; Toxicity; metals; Metal; Occupational exposure; Epidemiology; environmental carcinogens; particulate matter; Health and environment; Cross sectional study; Worker; Acetylation; Histone; Public health; Human; Air; histone modifications; Steel; Metal particle; Inhalation; Carcinogen; Suspended particle; Epigenetics; Environment; Occupational medicine
• ISSN: 0091-6765; 1552-9924
• DOI: 10.1289/ehp.1002955

Background: Epidemiology investigations have linked exposure to ambient and occupational air particulate matter (PM) with increased risk of lung cancer. PM contains carcinogenic and toxic metals, including arsenic and nickel, which have been shown in in vitro studies to induce histone modifications that activate gene expression by inducing open-chromatin states. Whether inhalation of metal components of PM induces histone modifications in human subjects is undetermined. Objectives: We investigated whether the metal components of PM determined activating histone modifications in 63 steel workers with well-characterized exposure to metal-rich PM. Methods: We determined histone 3 lysine 4 dimethylation (H3K4me2) and histone 3 lysine 9 acetylation (H3K9ac) on histones from blood leukocytes. Exposure to inhalable metal components (aluminum, manganese, nickel, zinc, arsenic, lead, iron) and to total PM was estimated for each study subject. Results: Both H3K4me2 and H3K9ac increased in association with years of employment in the plant (p-trend = 0.04 and 0.006, respectively). H3K4me2 increased in association with air levels of nickel [β = 0.16; 95% confidence interval (CI), 0.03-0.3], arsenic (β = 0.16; 95% CI, 0.02-0.3), and iron (β = 0.14; 95% CI, 0.01—0.26). H3K9ac showed nonsignificant positive associations with air levels of nickel (β = 0.24; 95% CI, -0.02 to 0.51), arsenic (β = 0.21; 95% CI, -0.06 to 0.48), and iron (β = 0.22; 95% CI, -0.03 to 0.47). Cumulative exposures to nickel and arsenic, defined as the product of years of employment by metal air levels, were positively correlated with both H3K4me2 (nickel: β = 0.16; 95% CI, 0.01-0.3; arsenic: β = 0.16; 95% CI, 0.03-0.29) and H3K9ac (nickel: β = 0.27; 95% CI, 0.01-0.54; arsenic: β = 0.28; 95% CI, 0.04-0.51). Conclusions: Our results indicate histone modifications as a novel epigenetic mechanism induced in human subjects by long-term exposure to inhalable nickel and arsenic.