title: Disruption of thyroid hormone (TH) levels and TH-regulated gene expression by polybrominated diphenyl ethers (PBDEs), polychlorinated biphenyls (PCBs), and hydroxylated PCBs in e-waste recycling workers.
abstract: Polybrominated diphenyl ethers (PBDEs) and polychlorinated biphenyls (PCBs) are the primary toxicants released by electronic waste (e-waste) recycling, but their adverse effects on people working in e-waste recycling or living near e-waste sites have not been studied well. In the present study, the serum concentrations of PBDEs, PCBs, and hydroxylated PCBs, the circulating levels of thyroid hormones (THs), and the mRNA levels of seven TH-regulated genes in peripheral blood leukocytes of e-waste recycling workers were analyzed. The associations of the hormone levels and gene expression with the exposure to these contaminants were examined using multiple linear regression models. There were nearly no associations of the TH levels with PCBs and hydroxylated PCBs, whereas elevated hormone (T4and T3) levels were associated with certain lower-brominated BDEs. While not statistically significant, we did observe a negative association between highly brominated PBDE congeners and thyroid-stimulating hormone (TSH) levels in the e-waste workers. The TH-regulated gene expression was more significantly associated with the organohalogen compounds (OHCs) than the TH levels in these workers. The TH-regulated gene expression was significantly associated with certain PCB and hydroxylated PCB congeners. However, the expression of most target genes was suppressed by PBDEs (mostly highly brominated congeners). This is the first evidence of alterations in TH-regulated gene expression in humans exposed to OHCs. Our findings indicated that OHCs may interfere with TH signaling and/or exert TH-like effects, leading to alterations in related gene expression in humans. Further research is needed to investigate the mechanisms of action and associated biological consequences of the gene expression disruption by OHCs.
authors.affiliation: Center for Environmental Health Research, South China Institute of Environmental Sciences, Ministry of Environmental Protection, Guangzhou, China.
authors.forename: Jing
authors.initials: J
authors.lastname: Zheng
authors.affiliation: State Key Laboratory for Biocontrol, School of Life Sciences, Sun Yat-Sen University, Guangzhou, China.
authors.forename: Chun-Tao
authors.initials: CT
authors.lastname: He
authors.affiliation: State Key Laboratory of Organic Geochemistry, Guangdong Provincial Key Laboratory of Environmental Protection and Resources Utilization, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou, China. Electronic address: chenshejun@gig.ac.cn.
authors.forename: She-Jun
authors.initials: SJ
authors.lastname: Chen
authors.affiliation: Center for Environmental Health Research, South China Institute of Environmental Sciences, Ministry of Environmental Protection, Guangzhou, China.
authors.forename: Xiao
authors.initials: X
authors.lastname: Yan
authors.affiliation: College of Natural Resources, University of California-Berkeley, Berkeley, CA, USA.
authors.forename: Mi-Na
authors.initials: MN
authors.lastname: Guo
authors.affiliation: Center for Environmental Health Research, South China Institute of Environmental Sciences, Ministry of Environmental Protection, Guangzhou, China.
authors.forename: Mei-Huan
authors.initials: MH
authors.lastname: Wang
authors.affiliation: Center for Environmental Health Research, South China Institute of Environmental Sciences, Ministry of Environmental Protection, Guangzhou, China.
authors.forename: Yun-Jiang
authors.initials: YJ
authors.lastname: Yu
authors.affiliation: State Key Laboratory for Biocontrol, School of Life Sciences, Sun Yat-Sen University, Guangzhou, China.
authors.forename: Zhong-Yi
authors.initials: ZY
authors.lastname: Yang
authors.affiliation: State Key Laboratory of Organic Geochemistry, Guangdong Provincial Key Laboratory of Environmental Protection and Resources Utilization, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou, China. Electronic address: nancymai@gig.ac.cn.
authors.forename: Bi-Xian
authors.initials: BX
authors.lastname: Mai
mesh_terms: D000328:Adult; D015415:Biomarkers / Q000097:blood; D002681:China; D059029:Electronic Waste; D004785:Environmental Pollutants / Q000097:blood*; D005260:Female; D005786:Gene Expression Regulation; D055768:Halogenated Diphenyl Ethers / Q000009:adverse effects / Q000097:blood*; D006801:Humans; D006900:Hydroxylation; D008297:Male; D008875:Middle Aged; D016273:Occupational Exposure; D011078:Polychlorinated Biphenyls / Q000009:adverse effects / Q000097:blood*; D012333:RNA, Messenger / Q000235:genetics; D059027:Recycling; D013963:Thyroid Hormones / Q000097:blood*; D055815:Young Adult
chemical_list: D015415:Biomarkers; D004785:Environmental Pollutants; D055768:Halogenated Diphenyl Ethers; D012333:RNA, Messenger; D013963:Thyroid Hormones; D011078:Polychlorinated Biphenyls
keywords: E-waste; Gene expression; Polybrominated diphenyl ethers; Polychlorinated biphenyls; Serum; Thyroid hormone