title: Epigenetic marker (LINE-1 promoter) methylation level was associated with occupational lead exposure.
abstract: BACKGROUND
  Occupational and environmental exposures to lead (Pb) are a worldwide concern. DNA methylation plays an important role in the development of Pb toxicity. Here, we try to find out the evidence to prove that the methylation of the LINE-1 promoter may be involved in Pb toxicity.
  
  
  METHODS
  To determine whether the methylation level of the LINE-1 is associated with the risk of Pb poisoning, we first constructed a Pb acetate-treated cell model to detect the association between LINE-1 methylation and Pb exposure. A case-control study involving 53 workers from a battery plant and 57 healthy volunteers with matching age and gender distribution was carried out. We employed methylation-specific real-time PCR to determine the relationship between LINE-1 methylation level and Pb exposure.
  
  
  RESULTS
  In the cell model, Pb exposure significantly decreased the level of LINE-1 methylation (p = 0.009). Significant difference in methylation frequencies was found between the exposed and control samples (p < 0.001). We also found a decreasing trend of LINE-1 methylation level with increasing blood Pb level (p < 0.001).
  
  
  CONCLUSIONS
  Therefore, the LINE-1 promoter methylation might contribute to the risk of Pb poisoning and identified a possible epigenetic biomarker for Pb toxicity, especially in individuals occupationally exposed to Pb.
authors.affiliation: Department of Occupational Health, Wuxi Center for Disease Control and Prevention, Wuxi, P. R. China. cpli_cn@yahoo.com
authors.forename: Chunping
authors.initials: C
authors.lastname: Li
authors.forename: Xiaolin
authors.initials: X
authors.lastname: Yang
authors.forename: Ming
authors.initials: M
authors.lastname: Xu
authors.forename: Jinlong
authors.initials: J
authors.lastname: Zhang
authors.forename: Na
authors.initials: N
authors.lastname: Sun
mesh_terms: D000328:Adult; D015415:Biomarkers / Q000097:blood / Q000378:metabolism; D016022:Case-Control Studies; D002681:China; D019175:DNA Methylation / Q000187:drug effects*; D004198:Disease Susceptibility / Q000139:chemically induced; D015536:Down-Regulation / Q000187:drug effects; D004736:Energy-Generating Resources; D044127:Epigenesis, Genetic / Q000187:drug effects*; D005260:Female; D057809:HEK293 Cells; D006801:Humans; D007221:Industry; D007854:Lead / Q000008:administration & dosage / Q000097:blood / Q000633:toxicity*; D007855:Lead Poisoning / Q000097:blood / Q000453:epidemiology / Q000209:etiology / Q000378:metabolism*; D020084:Long Interspersed Nucleotide Elements / Q000187:drug effects*; D008297:Male; D008875:Middle Aged; D009784:Occupational Diseases / Q000209:etiology / Q000378:metabolism; D016273:Occupational Exposure / Q000009:adverse effects*; D009942:Organometallic Compounds / Q000633:toxicity; D011401:Promoter Regions, Genetic / Q000187:drug effects*; D000078329:Workforce
chemical_list: D015415:Biomarkers; D009942:Organometallic Compounds; D007854:Lead; C008261:lead acetate