title: Traffic-derived particulate matter exposure and histone H3 modification: A repeated measures study.
abstract: BACKGROUND
  Airborne particulate matter (PM) may induce epigenetic changes that potentially lead to chronic diseases. Histone modifications regulate gene expression by influencing chromatin structure that can change gene expression status. We evaluated whether traffic-derived PM exposure is associated with four types of environmentally inducible global histone H3 modifications.
  
  
  METHODS
  The Beijing Truck Driver Air Pollution Study included 60 truck drivers and 60 office workers examined twice, 1-2 weeks apart, for ambient PM10(both day-of and 14-day average exposures), personal PM2.5, black carbon (BC), and elemental components (potassium, sulfur, iron, silicon, aluminum, zinc, calcium, and titanium). For both PM10measures, we obtained hourly ambient PM10data for the study period from the Beijing Municipal Environmental Bureau's 27 representatively distributed monitoring stations. We then calculated a 24h average for each examination day and a moving average of ambient PM10measured in the 14 days prior to each examination. Examinations measured global levels of H3 lysine 9 acetylation (H3K9ac), H3 lysine 9 tri-methylation (H3K9me3), H3 lysine 27 tri-methylation (H3K27me3), and H3 lysine 36 tri-methylation (H3K36me3) in blood leukocytes collected after work. We used adjusted linear mixed-effect models to examine percent changes in histone modifications per each μg/m3increase in PM exposure.
  
  
  RESULTS
  In all participants each μg/m3increase in 14-day average ambient PM10exposure was associated with lower H3K27me3 (β=-1.1%, 95% CI: -1.6, -0.6) and H3K36me3 levels (β=-0.8%, 95% CI: -1.4, -0.1). Occupation-stratified analyses showed associations between BC and both H3K9ac and H3K36me3 that were stronger in office workers (β=4.6%, 95% CI: 0.9, 8.4; and β=4.1%, 95% CI: 1.3; 7.0 respectively) than in truck drivers (β=0.1%, 95% CI: -1.3, 1.5; and β=0.9%, 95% CI: -0.9, 2.7, respectively; both pinteraction<0.05). Sex-stratified analyses showed associations between examination-day PM10and H3K9ac, and between BC and H3K9me3, were stronger in women (β=10.7%, 95% CI: 5.4, 16.2; and β=7.5%, 95% CI: 1.2, 14.2, respectively) than in men (β=1.4%, 95% CI: -0.9, 3.7; and β=0.9%, 95% CI: -0.9, 2.7, respectively; both pinteraction<0.05). We observed no associations between personal PM2.5or elemental components and histone modifications.
  
  
  CONCLUSIONS
  Our results suggest a possible role of global histone H3 modifications in effects of traffic-derived PM exposures, particularly BC exposure. Future studies should assess the roles of these modifications in human diseases and as potential mediators of air pollution-induced disease, in particular BC exposure.
authors.affiliation: Department of Preventive Medicine, Northwestern University Feinberg School of Medicine, Chicago, IL, USA; Health Sciences Integrated PhD Program, Northwestern University Feinberg School of Medicine, Chicago, IL, USA.
authors.forename: Yinan
authors.initials: Y
authors.lastname: Zheng
authors.affiliation: Department of Environmental Health, Harvard T.H. Chan School of Public Health, Boston, MA, USA; Department of Developmental Neurobiology, National Institute of Perinatology, Mexico City, Mexico.
authors.forename: Marco
authors.initials: M
authors.lastname: Sanchez-Guerra
authors.affiliation: Department of Preventive Medicine, Northwestern University Feinberg School of Medicine, Chicago, IL, USA; Driskill Graduate Program in Life Sciences, Northwestern University Feinberg School of Medicine, Chicago, IL, USA.
authors.forename: Zhou
authors.initials: Z
authors.lastname: Zhang
authors.affiliation: Department of Preventive Medicine, Northwestern University Feinberg School of Medicine, Chicago, IL, USA; Division of Epidemiology/Biostatistics, School of Public Health, University of Illinois-Chicago, Chicago, IL, USA.
authors.forename: Brian T
authors.initials: BT
authors.lastname: Joyce
authors.affiliation: Department of Environmental Health, Harvard T.H. Chan School of Public Health, Boston, MA, USA.
authors.forename: Jia
authors.initials: J
authors.lastname: Zhong
authors.affiliation: Department of Preventive Medicine, Northwestern University Feinberg School of Medicine, Chicago, IL, USA; Division of Epidemiology/Biostatistics, School of Public Health, University of Illinois-Chicago, Chicago, IL, USA.
authors.forename: Jacob K
authors.initials: JK
authors.lastname: Kresovich
authors.affiliation: Department of Preventive Medicine, Northwestern University Feinberg School of Medicine, Chicago, IL, USA; Robert H. Lurie Cancer Center, Northwestern University Feinberg School of Medicine, Chicago, IL, USA.
authors.forename: Lei
authors.initials: L
authors.lastname: Liu
authors.affiliation: Department of Preventive Medicine, Northwestern University Feinberg School of Medicine, Chicago, IL, USA; Robert H. Lurie Cancer Center, Northwestern University Feinberg School of Medicine, Chicago, IL, USA.
authors.forename: Wei
authors.initials: W
authors.lastname: Zhang
authors.affiliation: Department of Preventive Medicine, Northwestern University Feinberg School of Medicine, Chicago, IL, USA.
authors.forename: Tao
authors.initials: T
authors.lastname: Gao
authors.affiliation: Department of Safety Engineering, China Institute of Industrial Relations, Beijing, China.
authors.forename: Dou
authors.initials: D
authors.lastname: Chang
authors.affiliation: Department of Epidemiology, Harvard T.H. Chan School of Public Health, Boston, MA, USA.
authors.forename: Citlalli
authors.initials: C
authors.lastname: Osorio-Yanez
authors.affiliation: Department of Environmental Health, Harvard T.H. Chan School of Public Health, Boston, MA, USA.
authors.forename: Juan Jose
authors.initials: JJ
authors.lastname: Carmona
authors.affiliation: Department of Occupational and Environmental Health, Peking University Health Science Center, Beijing, China.
authors.forename: Sheng
authors.initials: S
authors.lastname: Wang
authors.affiliation: Department of Environmental Health, Harvard T.H. Chan School of Public Health, Boston, MA, USA.
authors.forename: John P
authors.initials: JP
authors.lastname: McCracken
authors.affiliation: Clinical Research Unit, Khoo Teck Puat Hospital, Singapore.
authors.forename: Xiao
authors.initials: X
authors.lastname: Zhang
authors.affiliation: Department of Environmental Medicine, New York University Langone Medical Center, Tuxedo, NY, USA.
authors.forename: Yana
authors.initials: Y
authors.lastname: Chervona
authors.affiliation: Center for Health Studies, Universidad del Valle de Guatemala, Guatemala City, Guatemala.
authors.forename: Anaite
authors.initials: A
authors.lastname: Díaz
authors.affiliation: Department of Clinical Sciences and Community Medicine, University of Milan and IRCCS Fondazione Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy.
authors.forename: Pier A
authors.initials: PA
authors.lastname: Bertazzi
authors.affiliation: Department of Environmental Health, Harvard T.H. Chan School of Public Health, Boston, MA, USA.
authors.forename: Petros
authors.initials: P
authors.lastname: Koutrakis
authors.affiliation: Department of Environmental Health, Harvard T.H. Chan School of Public Health, Boston, MA, USA.
authors.forename: Choong-Min
authors.initials: CM
authors.lastname: Kang
authors.affiliation: Department of Environmental Health, Harvard T.H. Chan School of Public Health, Boston, MA, USA.
authors.forename: Joel
authors.initials: J
authors.lastname: Schwartz
authors.affiliation: Department of Environmental Health Sciences, Columbia University Mailman School of Public Health, New York, NY, USA. Electronic address: ab4303@cumc.columbia.edu.
authors.forename: Andrea A
authors.initials: AA
authors.lastname: Baccarelli
authors.affiliation: Department of Preventive Medicine, Northwestern University Feinberg School of Medicine, Chicago, IL, USA; Robert H. Lurie Cancer Center, Northwestern University Feinberg School of Medicine, Chicago, IL, USA. Electronic address: l-hou@northwestern.edu.
authors.forename: Lifang
authors.initials: L
authors.lastname: Hou
mesh_terms: D000107:Acetylation; D000293:Adolescent; D000328:Adult; D000068476:Beijing; D004781:Environmental Exposure / Q000009:adverse effects* / Q000032:analysis; D005260:Female; D006657:Histones / Q000378:metabolism*; D006801:Humans; D007962:Leukocytes / Q000187:drug effects / Q000378:metabolism*; D008239:Lysine / Q000378:metabolism; D008297:Male; D008745:Methylation; D008875:Middle Aged; D052638:Particulate Matter / Q000009:adverse effects* / Q000032:analysis; D046188:Protein Modification, Translational; D001335:Vehicle Emissions; D055815:Young Adult
chemical_list: D006657:Histones; D052638:Particulate Matter; D001335:Vehicle Emissions; D008239:Lysine
keywords: Acetylation; Epigenetics; Histone H3; Methylation; Particulate matter