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Moksnes MR, Hansen AF, Wolford BN, Thomas LF, Rasheed H, Simić A, Bhatta L, Brantsæter AL, Surakka I, Zhou W, Magnus P, Njølstad PR, Andreassen OA, Syversen T, Zheng J, Fritsche LG, Evans DM, Warrington NM, Nøst TH, Åsvold BO, Flaten TP, Willer CJ, Hveem K, Brumpton BM. A genome-wide association study provides insights into the genetic etiology of 57 essential and non-essential trace elements in humans. Commun Biol 2024; 7:432. [PMID: 38594418 PMCID: PMC11004147 DOI: 10.1038/s42003-024-06101-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2023] [Accepted: 03/22/2024] [Indexed: 04/11/2024] Open
Abstract
Trace elements are important for human health but may exert toxic or adverse effects. Mechanisms of uptake, distribution, metabolism, and excretion are partly under genetic control but have not yet been extensively mapped. Here we report a comprehensive multi-element genome-wide association study of 57 essential and non-essential trace elements. We perform genome-wide association meta-analyses of 14 trace elements in up to 6564 Scandinavian whole blood samples, and genome-wide association studies of 43 trace elements in up to 2819 samples measured only in the Trøndelag Health Study (HUNT). We identify 11 novel genetic loci associated with blood concentrations of arsenic, cadmium, manganese, selenium, and zinc in genome-wide association meta-analyses. In HUNT, several genome-wide significant loci are also indicated for other trace elements. Using two-sample Mendelian randomization, we find several indications of weak to moderate effects on health outcomes, the most precise being a weak harmful effect of increased zinc on prostate cancer. However, independent validation is needed. Our current understanding of trace element-associated genetic variants may help establish consequences of trace elements on human health.
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Affiliation(s)
- Marta R Moksnes
- HUNT Center for Molecular and Clinical Epidemiology, Department of Public Health and Nursing, NTNU-Norwegian University of Science and Technology, Trondheim, Norway.
| | - Ailin F Hansen
- HUNT Center for Molecular and Clinical Epidemiology, Department of Public Health and Nursing, NTNU-Norwegian University of Science and Technology, Trondheim, Norway
| | - Brooke N Wolford
- HUNT Center for Molecular and Clinical Epidemiology, Department of Public Health and Nursing, NTNU-Norwegian University of Science and Technology, Trondheim, Norway
| | - Laurent F Thomas
- HUNT Center for Molecular and Clinical Epidemiology, Department of Public Health and Nursing, NTNU-Norwegian University of Science and Technology, Trondheim, Norway
- Department of Clinical and Molecular Medicine, NTNU-Norwegian University of Science and Technology, Trondheim, Norway
- BioCore-Bioinformatics Core Facility, NTNU-Norwegian University of Science and Technology, Trondheim, Norway
- Clinic of Laboratory Medicine, St. Olav's Hospital, Trondheim University Hospital, Trondheim, Norway
| | - Humaira Rasheed
- HUNT Center for Molecular and Clinical Epidemiology, Department of Public Health and Nursing, NTNU-Norwegian University of Science and Technology, Trondheim, Norway
- MRC Integrative Epidemiology Unit, Population Health Sciences, Bristol Medical School, University of Bristol, Bristol, UK
- Division of Medicine and Laboratory Sciences, University of Oslo, Oslo, Norway
| | - Anica Simić
- Department of Chemistry, NTNU-Norwegian University of Science and Technology, Trondheim, Norway
| | - Laxmi Bhatta
- HUNT Center for Molecular and Clinical Epidemiology, Department of Public Health and Nursing, NTNU-Norwegian University of Science and Technology, Trondheim, Norway
| | - Anne Lise Brantsæter
- Department of Food Safety, Division of Climate and Environmental Health, Norwegian Institute of Public Health, Oslo, Norway
| | - Ida Surakka
- Department of Internal Medicine, Division of Cardiology, University of Michigan, Ann Arbor, MI, USA
| | - Wei Zhou
- Department of Computational Medicine and Bioinformatics, University of Michigan, Ann Arbor, MI, USA
- Analytic and Translational Genetics Unit, Massachusetts General Hospital, Boston, MA, USA
- Program in Medical and Population Genetics, Broad Institute of Harvard and MIT, Cambridge, MA, USA
| | - Per Magnus
- Centre for Fertility and Health, Norwegian Institute of Public Health, Oslo, Norway
| | - Pål R Njølstad
- Mohn Center for Diabetes Precision Medicine, Department of Clinical Science, University of Bergen, Bergen, Norway
- Children and Youth Clinic, Haukeland University Hospital, Bergen, Norway
| | - Ole A Andreassen
- NORMENT Centre, University of Oslo, Oslo, Norway
- Division of Mental Health and Addiction, Oslo University Hospital, Oslo, Norway
| | - Tore Syversen
- Department of Neuroscience, NTNU-Norwegian University of Science and Technology, Trondheim, Norway
| | - Jie Zheng
- Department of Endocrine and Metabolic Diseases, Shanghai Institute of Endocrine and Metabolic Diseases, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
- Shanghai National Clinical Research Center for Metabolic Diseases, Key Laboratory for Endocrine and Metabolic Diseases of the National Health Commission of the PR China, Shanghai Key Laboratory for Endocrine Tumor, Shanghai Digital Medicine Innovation Center, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
- MRC Integrative Epidemiology Unit (IEU), Bristol Medical School, University of Bristol, Bristol, UK
| | - Lars G Fritsche
- Department of Biostatistics, University of Michigan School of Public Health, Ann Arbor, MI, USA
- Center for Statistical Genetics, University of Michigan School of Public Health, Ann Arbor, MI, USA
| | - David M Evans
- Institute for Molecular Biosciences, The University of Queensland, Brisbane, QLD, Australia
- Frazer Institute, The University of Queensland, Woolloongabba, QLD, Australia
- MRC Integrative Epidemiology Unit (IEU), University of Bristol, Bristol, UK
| | - Nicole M Warrington
- HUNT Center for Molecular and Clinical Epidemiology, Department of Public Health and Nursing, NTNU-Norwegian University of Science and Technology, Trondheim, Norway
- Institute for Molecular Biosciences, The University of Queensland, Brisbane, QLD, Australia
- Frazer Institute, The University of Queensland, Woolloongabba, QLD, Australia
- MRC Integrative Epidemiology Unit (IEU), University of Bristol, Bristol, UK
| | - Therese H Nøst
- HUNT Center for Molecular and Clinical Epidemiology, Department of Public Health and Nursing, NTNU-Norwegian University of Science and Technology, Trondheim, Norway
- Department of Community Medicine, UiT The Arctic University of Norway, Tromsø, Norway
| | - Bjørn Olav Åsvold
- HUNT Center for Molecular and Clinical Epidemiology, Department of Public Health and Nursing, NTNU-Norwegian University of Science and Technology, Trondheim, Norway
- HUNT Research Centre, Department of Public Health and Nursing, NTNU-Norwegian University of Science and Technology, Levanger, Norway
- Department of Endocrinology, Clinic of Medicine, St. Olav's Hospital, Trondheim University Hospital, Trondheim, Norway
| | - Trond Peder Flaten
- Department of Chemistry, NTNU-Norwegian University of Science and Technology, Trondheim, Norway
| | - Cristen J Willer
- HUNT Center for Molecular and Clinical Epidemiology, Department of Public Health and Nursing, NTNU-Norwegian University of Science and Technology, Trondheim, Norway
- Department of Computational Medicine and Bioinformatics, University of Michigan, Ann Arbor, MI, USA
- Division of Cardiovascular Medicine, Department of Internal Medicine, University of Michigan, Ann Arbor, MI, USA
- Department of Human Genetics, University of Michigan, Ann Arbor, MI, USA
| | - Kristian Hveem
- HUNT Center for Molecular and Clinical Epidemiology, Department of Public Health and Nursing, NTNU-Norwegian University of Science and Technology, Trondheim, Norway
- HUNT Research Centre, Department of Public Health and Nursing, NTNU-Norwegian University of Science and Technology, Levanger, Norway
| | - Ben M Brumpton
- HUNT Center for Molecular and Clinical Epidemiology, Department of Public Health and Nursing, NTNU-Norwegian University of Science and Technology, Trondheim, Norway.
- HUNT Research Centre, Department of Public Health and Nursing, NTNU-Norwegian University of Science and Technology, Levanger, Norway.
- Clinic of Medicine, St. Olav's Hospital, Trondheim University Hospital, Trondheim, Norway.
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Cuomo D, Nitcher M, Barba E, Feinberg AP, Rusyn I, Chiu WA, Threadgill DW. Refining risk estimates for lead in drinking water based on the impact of genetics and diet on blood lead levels using the Collaborative Cross mouse population. Toxicol Sci 2023; 194:226-234. [PMID: 37243727 PMCID: PMC10375319 DOI: 10.1093/toxsci/kfad054] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/29/2023] Open
Abstract
Blood lead (Pb) level (BLL) is a commonly used biomarker to evaluate associations with health effects. However, interventions to reduce the adverse effects of Pb require relating BLL to external exposure. Moreover, risk mitigation actions need to ensure protection of more susceptible individuals with a greater tendency to accumulate Pb. Because little data is available to quantify inter-individual variability in biokinetics of Pb, we investigated the influence of genetics and diet on BLL in the genetically diverse Collaborative Cross (CC) mouse population. Adult female mice from 49 CC strains received either a standard mouse chow or a chow mimicking the American diet while being provided water ad libitum with 1000 ppm Pb for 4 weeks. In both arms of the study, inter-strain variability was observed; however, in American diet-fed animals, the BLL was greater and more variable. Importantly, the degree of variation in BLL among strains on the American diet was greater (2.3) than the default variability estimate (1.6) used in setting the regulatory standards. Genetic analysis identified suggestive diet-associated haplotypes that were associated with variation in BLL, largely contributed by the PWK/PhJ strain. This study quantified the variation in BLL that is due to genetic background, diet, and their interactions, and observed that it may be greater than that assumed for current regulatory standards for Pb in drinking water. Moreover, this work highlights the need of characterizing inter-individual variation in BLL to ensure adequate public health interventions aimed at reducing human health risks from Pb.
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Affiliation(s)
- Danila Cuomo
- Department of Cell Biology and Genetics, Texas A&M University, College Station, Texas, USA
| | - Megan Nitcher
- Department of Cell Biology and Genetics, Texas A&M University, College Station, Texas, USA
| | - Estefania Barba
- Department of Cell Biology and Genetics, Texas A&M University, College Station, Texas, USA
| | - Andrew P Feinberg
- Center for Epigenetics, Department of Biomedical Engineering, Johns Hopkins University, Baltimore, Maryland, USA
- Center for Epigenetics, Department of Medicine, Johns Hopkins University, Baltimore, Maryland, USA
- Center for Epigenetics, Department of Mental Health, Johns Hopkins University, Baltimore, Maryland, USA
| | - Ivan Rusyn
- Department of Veterinary Physiology and Pharmacology, Texas A&M University, College Station, Texas, USA
| | - Weihsueh A Chiu
- Department of Veterinary Physiology and Pharmacology, Texas A&M University, College Station, Texas, USA
| | - David W Threadgill
- Department of Cell Biology and Genetics, Texas A&M University, College Station, Texas, USA
- Department of Nutrition, Texas A&M University, College Station, Texas, USA
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Cuomo D, Foster MJ, Threadgill D. Systemic review of genetic and epigenetic factors underlying differential toxicity to environmental lead (Pb) exposure. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2022; 29:35583-35598. [PMID: 35244845 PMCID: PMC9893814 DOI: 10.1007/s11356-022-19333-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/13/2021] [Accepted: 02/17/2022] [Indexed: 05/03/2023]
Abstract
Lead (Pb) poisoning is a major public health concern in environmental justice communities of the USA and in many developing countries. There is no identified safety threshold for lead in blood, as low-level Pb exposures can lead to severe toxicity in highly susceptible individuals and late onset of diseases from early-life exposure. However, identifying "susceptibility genes" or "early exposure biomarkers" remains challenging in human populations. There is a considerable variation in susceptibility to harmful effects from Pb exposure in the general population, likely due to the complex interplay of genetic and/or epigenetic factors. This systematic review summarizes current state of knowledge on the role of genetic and epigenetic factors in determining individual susceptibility in response to environmental Pb exposure in humans and rodents. Although a number of common genetic and epigenetic factors have been identified, the reviewed studies, which link these factors to various adverse health outcomes following Pb exposure, have provided somewhat inconsistent evidence of main health effects. Acknowledging the compelling need for new approaches could guide us to better characterize individual responses, predict potential adverse outcomes, and identify accurate and usable biomarkers for Pb exposure to improve mitigation therapies to reduce future adverse health outcomes of Pb exposure.
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Affiliation(s)
- Danila Cuomo
- Department of Molecular and Cellular Medicine, Texas A&M University, College Station, TX, USA.
| | - Margaret J Foster
- Medical Sciences Library, Texas A&M University, College Station, TX, USA
| | - David Threadgill
- Department of Molecular and Cellular Medicine and Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX, USA.
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Hujoel IA, Hujoel MLA. The Role of Copper and Zinc in Irritable Bowel Syndrome: A Mendelian Randomization Study. Am J Epidemiol 2022; 191:85-92. [PMID: 34132328 DOI: 10.1093/aje/kwab180] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2020] [Revised: 05/30/2021] [Accepted: 06/11/2021] [Indexed: 11/14/2022] Open
Abstract
Irritable bowel syndrome (IBS) has been associated with copper and zinc imbalance and a zinc-deficient diet. Mendelian randomization was used in this study to evaluate if genetically determined copper and zinc levels play a causal role in the development of IBS. Three single-nucleotide polymorphisms (SNPs; rs1175550, rs2769264, and rs2769270) associated with erythrocyte copper levels, and 3 SNPs associated with erythrocyte zinc levels (rs11638477, rs1532423, and rs2120019) in the Australian Twin Study (1993-1996 and 2001-2005) were used as instrumental variables for levels of these metals. The association of these SNPs with IBS was tested using summary statistics computed from data on 340,331 individuals from the UK Biobank, 5,548 of whom had IBS (2006-2010). Genetically predicted high serum copper levels were associated with a lower risk of IBS (odds ratio = 0.89; 95% confidence interval: 0.80, 0.98). Genetically predicted, high serum zinc levels were nonsignificantly associated with a higher risk of IBS (odds ratio = 1.06; 95% confidence interval: 0.95, 1.18). Sensitivity analysis did not suggest the presence of pleiotropy. These results suggest that high erythrocyte copper levels may be protective against IBS development. Targeting higher levels, therefore, may provide an avenue to reduce the likelihood of IBS development in high-risk individuals.
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Exposure to Toxic Heavy Metals Can Influence Homocysteine Metabolism? Antioxidants (Basel) 2019; 9:antiox9010030. [PMID: 31905706 PMCID: PMC7022705 DOI: 10.3390/antiox9010030] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2019] [Revised: 12/20/2019] [Accepted: 12/24/2019] [Indexed: 12/21/2022] Open
Abstract
BACKGROUND Homocysteine is a sulfur amino acid whose metabolism is activated in two pathways: remethylation to methionine, which requires folate and vitamin B12, and transsulfuration to cystathionine, which needs pyridoxal-5'-phosphate. High homocysteine level increases the risk of developing heart disease, stroke, peripheral vascular diseases, and cognitive impairment. Some evidence showed that exposure to these metals increased plasma homocysteine levels. METHODS A systematic review was carried out to clarify the relationship between homocysteine blood levels and exposure to toxic heavy metals (Lead, Cadmium, Mercury, and Chromium). RESULTS The results of this systematic review indicate that exposure to Pb, Cr, Cd, and Hg is connected with nonphysiological homocysteine levels or vitamin B12 and folate serum concentrations. CONCLUSIONS These findings reinforce the importance of involvement in exposure to heavy metals in homocysteine metabolism. This supports the role of blood metals as potential upstream modifiable risk factors to prevent the development of other established risk factors as hyperhomocysteinemia.
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Mani MS, Kabekkodu SP, Joshi MB, Dsouza HS. Ecogenetics of lead toxicity and its influence on risk assessment. Hum Exp Toxicol 2019; 38:1031-1059. [PMID: 31117811 DOI: 10.1177/0960327119851253] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/02/2024]
Abstract
Lead (Pb) toxicity is a public health problem affecting millions worldwide. Advances in 'omic' technology have paved the way to toxico-genomics which is currently revolutionizing the understanding of interindividual variations in susceptibility to Pb toxicity and its functional consequences to exposure. Our objective was to identify, comprehensively analyze, and curate all the potential genetic and epigenetic biomarkers studied to date in relation to Pb toxicity and its association with diseases. We screened a volume of research articles that focused on Pb toxicity and its association with genetic and epigenetic signatures in the perspective of occupational and environmental Pb exposure. Due to wide variations in population size, ethnicity, age-groups, and source of exposure in different studies, researchers continue to be skeptical on the topic of the influence of genetic variations in Pb toxicity. However, surface knowledge of the underlying genetic factors will aid in elucidating the mechanism of action of Pb. Moreover, in recent years, the application of epigenetics in Pb toxicity has become a promising area in toxicology to understand the influence of epigenetic mechanisms such as DNA methylation, chromatin remodeling, and small RNAs for the regulation of genes in response to Pb exposure during early life. Growing evidences of ecogenetic understanding (both genetic and epigenetic processes) in a dose-dependent manner may help uncover the mechanism of action of Pb and in the identification of susceptible groups. Such studies will further help in refining uncertainty factors and in addressing risk assessment of Pb poisoning.
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Affiliation(s)
- M S Mani
- 1 Department of Radiation Biology and Toxicology, Manipal School of Life Sciences, Manipal Academy of Higher Education, Manipal, Karnataka, India
| | - S P Kabekkodu
- 2 Department of Cellular and Molecular Biology, Manipal School of Life Sciences, Manipal Academy of Higher Education, Manipal, Karnataka, India
| | - M B Joshi
- 3 Department of Ageing, Manipal School of Life Sciences, Manipal Academy of Higher Education, Manipal, Karnataka, India
| | - H S Dsouza
- 1 Department of Radiation Biology and Toxicology, Manipal School of Life Sciences, Manipal Academy of Higher Education, Manipal, Karnataka, India
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Chen CJ, Lin TY, Wang CL, Ho CK, Chuang HY, Yu HS. Interactive Effects between Chronic Lead Exposure and the Homeostatic Iron Regulator Transport HFE Polymorphism on the Human Red Blood Cell Mean Corpuscular Volume (MCV). INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2019; 16:E354. [PMID: 30691187 PMCID: PMC6388122 DOI: 10.3390/ijerph16030354] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/27/2018] [Revised: 01/01/2019] [Accepted: 01/12/2019] [Indexed: 12/16/2022]
Abstract
Research has shown that long-term exposure to lead harms the hematological system. The homeostatic iron regulator HFE (hemochromatosis) mutation, which has been shown to affect iron absorption and iron overload, is hypothesized to be related to lead intoxication in vulnerable individuals. The aim of our study was to investigate whether the HFE genotype modifies the blood lead levels that affect the distributions of serum iron and other red blood cell indices. Overall, 121 lead workers and 117 unexposed age-matched subjects were recruited for the study. The collected data included the blood lead levels, complete blood count, serum iron, total iron binding capacity, transferrin, and ferritin, which were measured during regular physical examinations. All subjects filled out questionnaires that included demographic information, medical history, and alcohol and tobacco consumption. HFE genotyping for C282Y and H63D was determined using polymerase chain reaction and restriction fragment length polymorphism (PCR/RFLP). The mean blood lead level in lead workers was 19.75 µg/dL and was 2.86 µg/dL in unexposed subjects. Of 238 subjects, 221 (92.9%) subjects were wild-type (CCHH) for HFE C282Y and H63D, and 17 (7.1%) subjects were heterozygous for a H63D mutation (CCHD). Multiple linear regression analysis showed that blood lead was significantly negatively associated with hemoglobin (Hb), mean corpuscular hemoglobin concentration (MCHC), and mean corpuscular volume (MCV), whereas the HFE variant was associated negatively with MCV and positively with ferritin. An interactive influence on MCV was identified between blood lead and HFE variants. Our research found a significant modifying effect of the HFE variant, which possibly affected MCV. The HFE H63D heterozygous (CCHD) variant seemed to provide a protective factor against lead toxicity. Future studies should focus on competing binding proteins between iron and lead influenced by gene variation.
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Affiliation(s)
- Chien-Juan Chen
- Graduate Institute of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung 80708, Taiwan.
| | - Ting-Yi Lin
- Master Program of Public Health, Kaohsiung Medical University, Kaohsiung 80708, Taiwan.
| | - Chao-Ling Wang
- Department of Environmental and Occupational Medicine, Kaohsiung Medical University Hospital, Kaohsiung 80708, Taiwan.
| | - Chi-Kung Ho
- Department of Environmental and Occupational Medicine, Kaohsiung Medical University Hospital, Kaohsiung 80708, Taiwan.
- Department of Public Health, College of Health Sciences, Kaohsiung Medical University, Kaohsiung 80708, Taiwan.
| | - Hung-Yi Chuang
- Graduate Institute of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung 80708, Taiwan.
- Department of Environmental and Occupational Medicine, Kaohsiung Medical University Hospital, Kaohsiung 80708, Taiwan.
- Department of Public Health, College of Health Sciences, Kaohsiung Medical University, Kaohsiung 80708, Taiwan.
| | - Hsin-Su Yu
- Graduate Institute of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung 80708, Taiwan.
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Jarvis P, Quy K, Macadam J, Edwards M, Smith M. Intake of lead (Pb) from tap water of homes with leaded and low lead plumbing systems. THE SCIENCE OF THE TOTAL ENVIRONMENT 2018; 644:1346-1356. [PMID: 30743847 DOI: 10.1016/j.scitotenv.2018.07.064] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/09/2018] [Revised: 07/04/2018] [Accepted: 07/05/2018] [Indexed: 06/09/2023]
Abstract
Methods of quantifying consumer exposure to lead in drinking water are increasingly of interest worldwide, especially those that account for consumer drinking habits and the semi-random nature of water lead release from plumbing systems. A duplicate intake protocol was developed in which individuals took a sub-sample from each measured drink they consumed in the home over three days in both winter and summer. The protocol was applied in two different water company regional areas (WC1 and WC2), selected to represent high risk situations in England, with the presence or absence of lead service pipes or phosphate corrosion control. Consumer exposure to lead was highest in properties with lead service pipes, served by water without P dosing. The protocol indicated that a small number of individuals in the study, all from homes with lead service pipes, consumed lead at levels that exceeded current guidance from the European Food Standards Agency. Children's potential blood lead levels (BLLs) were estimated using the Internal Exposure Uptake Biokinetic model (IEUBK). The IEUBK model predicted that up to 46% of children aged 0-7 years old may have elevated BLLs (>5 μg/dL) when consuming the worst case drinking water quality (>99%ile). Estimating blood lead levels using the IEUBK model for more typical lead concentrations in drinking water identified in this study (between 0.1 and 7.1 μg/L), predicts that elevated BLLs may affect a small proportion of children between 0 and 7 years old.
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Affiliation(s)
- Peter Jarvis
- Cranfield Water Science Institute, Cranfield University, Cranfield, Bedfordshire MK43 0AL, UK.
| | - Katie Quy
- Thomas Coram Research Unit, UCL Institute of Education, 20 Bedford Way, London WC1H 0AA, UK
| | - Jitka Macadam
- Cranfield Water Science Institute, Cranfield University, Cranfield, Bedfordshire MK43 0AL, UK
| | - Marc Edwards
- The Charles E. Via, Jr. Department of Civil & Environmental Engineering, Virginia Tech, Blacksburg, VA 24061, USA
| | - Marjorie Smith
- Thomas Coram Research Unit, UCL Institute of Education, 20 Bedford Way, London WC1H 0AA, UK
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Rooney JPK, Woods NF, Martin MD, Woods JS. Genetic polymorphisms of GRIN2A and GRIN2B modify the neurobehavioral effects of low-level lead exposure in children. ENVIRONMENTAL RESEARCH 2018; 165:1-10. [PMID: 29655037 PMCID: PMC5999567 DOI: 10.1016/j.envres.2018.04.001] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/19/2017] [Revised: 03/31/2018] [Accepted: 04/02/2018] [Indexed: 05/10/2023]
Abstract
Lead (Pb) is neurotoxic and children are highly susceptible to this effect, particularly within the context of continuous low-level Pb exposure. A current major challenge is identification of children who may be uniquely susceptible to Pb toxicity because of genetic predisposition. Learning and memory are among the neurobehavioral processes that are most notably affected by Pb exposure, and modification of N-methyl-D-aspartate receptors (NMDAR) that regulate these processes during development are postulated to underlie these adverse effects of Pb. We examined the hypothesis that polymorphic variants of genes encoding glutamate receptor, ionotropic, NMDAR subunits 2A and 2B, GRIN2A and GRIN2B, exacerbate the adverse effects of Pb exposure on these processes in children. Participants were subjects who participated as children in the Casa Pia Dental Amalgam Clinical Trial and for whom baseline blood Pb concentrations and annual neurobehavioral test results over the 7 year course of the clinical trial were available. Genotyping assays were performed for variants of GRIN2A (rs727605 and rs1070503) and GRIN2B (rs7301328 and rs1806201) on biological samples acquired from 330 of the original 507 trial participants. Regression modeling strategies were employed to evaluate the association between genotype status, Pb exposure, and neurobehavioral test outcomes. Numerous significant adverse interaction effects between variants of both GRIN2A and GRIN2B, individually and in combination, and Pb exposure were observed particularly among boys, preferentially within the domains of Learning & Memory and Executive Function. In contrast, very few interaction effects were observed among similarly genotyped girls with comparable Pb exposure. These findings support observations of an essential role of GRIN2A and GRIN2B on developmental processes underlying learning and memory as well as other neurological functions in children and demonstrate, further, modification of Pb effects on these processes by specific variants of both GRIN2A and GRIN2B genes. These observations highlight the importance of genetic factors in defining susceptibility to Pb neurotoxicity and may have important public health implications for future strategies aimed at protecting children and adolescents from potential health risks associated with low-level Pb exposure.
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Affiliation(s)
- James P K Rooney
- Academic Unit of Neurology, Trinity Biomedical Sciences Institute, Trinity College Dublin, Ireland.
| | - Nancy F Woods
- Department of Biobehavioral Nursing and Health Informatics, University of Washington, Seattle, WA, USA
| | - Michael D Martin
- Departments of Oral Medicine and Epidemiology, University of Washington, Seattle, WA, USA
| | - James S Woods
- Department of Environmental and Occupational Health Sciences, University of Washington, Seattle, WA, USA
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10
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Lamichhane DK, Leem JH, Park CS, Ha M, Ha EH, Kim HC, Lee JY, Ko JK, Kim Y, Hong YC. Associations between prenatal lead exposure and birth outcomes: Modification by sex and GSTM1/GSTT1 polymorphism. THE SCIENCE OF THE TOTAL ENVIRONMENT 2018; 619-620:176-184. [PMID: 29145054 DOI: 10.1016/j.scitotenv.2017.09.159] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/30/2017] [Revised: 09/14/2017] [Accepted: 09/16/2017] [Indexed: 06/07/2023]
Abstract
Maternal lead exposure is associated with poor birth outcomes. However, modifying effects of polymorphism in glutathione S-transferases (GST) gene and infant sex remain unexplored. Our aim was to evaluate whether associations between prenatal lead and birth outcomes differed by maternal GST genes and infant sex. Prospective data of 782 mother-child pairs from Mothers and Children's Environmental Health (MOCEH) study were used. The genotyping of GST-mu 1 (GSTM1) and theta-1 (GSTT1) polymorphisms was carried out using polymerase chain reaction. Multivariable linear regression was used to examine whether the association between blood lead (BPb) level and birth outcomes (birthweight, length, and head circumference) varied by maternal GST genes and sex. We did not find a statistically significant association between prenatal BPb levels and birth outcomes; in stratified analyses, the association between higher BPb level during early pregnancy and lower birthweight (β=-224 per square root increase in BPb; 95% confidence interval (CI): -426, -21; false discovery rate p=0.036) was significant in males of mothers with GSTM1 null. Results were similar for head circumference model (β=-0.78 per square root increase in BPb; 95% CI: -1.69, 0.14, p=0.095), but the level of significance was borderline. Head circumference model showed a significant three-way interaction among BPb during early pregnancy, GSTM1, and sex (p=0.046). For combined analysis with GSTM1 and GSTT1, GSTM1 null and GSTT1 present group showed a significant inverse association of BPb with birthweight and head circumference in males. Our findings of the most evident effects of BPb on the reduced birthweight and head circumference in male born to the mother with GSTM1 null may suggest a biological interaction among lead, GST genes and sex in detoxification process during fetal development.
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Affiliation(s)
- Dirga Kumar Lamichhane
- Department of Social and Preventive Medicine, College of Medicine, Inha University, Incheon, Republic of Korea
| | - Jong-Han Leem
- Department of Social and Preventive Medicine, College of Medicine, Inha University, Incheon, Republic of Korea; Department of Occupational and Environmental Medicine, Inha University Hospital, Incheon, Republic of Korea.
| | - Chang-Shin Park
- Department of Pharmacology, College of Medicine, Inha University, Incheon, Republic of Korea
| | - Mina Ha
- Department of Preventive Medicine, College of Medicine, Dankook University, Cheonan, Republic of Korea
| | - Eun-Hee Ha
- Department of Preventive Medicine, College of Medicine, Ewha Womans University, Seoul, Republic of Korea
| | - Hwan-Cheol Kim
- Department of Social and Preventive Medicine, College of Medicine, Inha University, Incheon, Republic of Korea; Department of Occupational and Environmental Medicine, Inha University Hospital, Incheon, Republic of Korea
| | - Ji-Young Lee
- Department of Preventive Medicine, College of Medicine, Ewha Womans University, Seoul, Republic of Korea
| | - Jung Keun Ko
- Department of Social and Preventive Medicine, College of Medicine, Inha University, Incheon, Republic of Korea
| | - Yangho Kim
- Department of Occupational and Environmental Medicine, University of Ulsan, College of Medicine, Ulsan University Hospital, Ulsan, Republic of Korea
| | - Yun-Chul Hong
- Department of Preventive Medicine, College of Medicine, Seoul National University, Seoul, Republic of Korea
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Environment and Human Health: The Challenge of Uncertainty in Risk Assessment. GEOSCIENCES 2018. [DOI: 10.3390/geosciences8010024] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
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12
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Zhou S, Luoma SE, St. Armour GE, Thakkar E, Mackay TFC, Anholt RRH. A Drosophila model for toxicogenomics: Genetic variation in susceptibility to heavy metal exposure. PLoS Genet 2017; 13:e1006907. [PMID: 28732062 PMCID: PMC5544243 DOI: 10.1371/journal.pgen.1006907] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2017] [Revised: 08/04/2017] [Accepted: 07/06/2017] [Indexed: 12/20/2022] Open
Abstract
The genetic factors that give rise to variation in susceptibility to environmental toxins remain largely unexplored. Studies on genetic variation in susceptibility to environmental toxins are challenging in human populations, due to the variety of clinical symptoms and difficulty in determining which symptoms causally result from toxic exposure; uncontrolled environments, often with exposure to multiple toxicants; and difficulty in relating phenotypic effect size to toxic dose, especially when symptoms become manifest with a substantial time lag. Drosophila melanogaster is a powerful model that enables genome-wide studies for the identification of allelic variants that contribute to variation in susceptibility to environmental toxins, since the genetic background, environmental rearing conditions and toxic exposure can be precisely controlled. Here, we used extreme QTL mapping in an outbred population derived from the D. melanogaster Genetic Reference Panel to identify alleles associated with resistance to lead and/or cadmium, two ubiquitous environmental toxins that present serious health risks. We identified single nucleotide polymorphisms (SNPs) associated with variation in resistance to both heavy metals as well as SNPs associated with resistance specific to each of them. The effects of these SNPs were largely sex-specific. We applied mutational and RNAi analyses to 33 candidate genes and functionally validated 28 of them. We constructed networks of candidate genes as blueprints for orthologous networks of human genes. The latter not only provided functional contexts for known human targets of heavy metal toxicity, but also implicated novel candidate susceptibility genes. These studies validate Drosophila as a translational toxicogenomics gene discovery system. Although physiological effects of environmental toxins are well documented, we know little about the genetic factors that determine individual variation in susceptibility to toxins. Such information is difficult to obtain in human populations due to heterogeneity in genetic background and environmental exposure, and the diversity of symptoms and time lag with which they appear after toxic exposure. Here, we show that the fruit fly, Drosophila, can serve as a powerful genetic model system to elucidate the genetic underpinnings that contribute to individual variation in resistance to toxicity, using lead and cadmium exposure as an experimental paradigm. We identified genes that harbor genetic variants that contribute to individual variation in resistance to heavy metal exposure. Furthermore, we constructed genetic networks on which we could superimpose human counterparts of Drosophila genes. We were able to place human genes previously implicated in heavy metal toxicity in biological context and identify novel targets for heavy metal toxicity. Thus, we demonstrate that based on evolutionary conservation of fundamental biological processes, we can use Drosophila as a powerful translational model for toxicogenomics studies.
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Affiliation(s)
- Shanshan Zhou
- Program in Genetics, W. M. Keck Center for Behavioral Biology, and Department of Biological Sciences, North Carolina State University, Raleigh, North Carolina, United States of America
| | - Sarah E. Luoma
- Program in Genetics, W. M. Keck Center for Behavioral Biology, and Department of Biological Sciences, North Carolina State University, Raleigh, North Carolina, United States of America
| | - Genevieve E. St. Armour
- Program in Genetics, W. M. Keck Center for Behavioral Biology, and Department of Biological Sciences, North Carolina State University, Raleigh, North Carolina, United States of America
| | - Esha Thakkar
- Enloe Magnet High School, Raleigh, North Carolina, United States of America
| | - Trudy F. C. Mackay
- Program in Genetics, W. M. Keck Center for Behavioral Biology, and Department of Biological Sciences, North Carolina State University, Raleigh, North Carolina, United States of America
| | - Robert R. H. Anholt
- Program in Genetics, W. M. Keck Center for Behavioral Biology, and Department of Biological Sciences, North Carolina State University, Raleigh, North Carolina, United States of America
- * E-mail:
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Kim NS, Ahn J, Lee BK, Park J, Kim Y. Environmental exposures to lead, mercury, and cadmium among South Korean teenagers (KNHANES 2010-2013): Body burden and risk factors. ENVIRONMENTAL RESEARCH 2017; 156:468-476. [PMID: 28415041 DOI: 10.1016/j.envres.2017.04.009] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/11/2016] [Revised: 02/22/2017] [Accepted: 04/07/2017] [Indexed: 06/07/2023]
Abstract
INTRODUCTION Limited information is available on the association of age and sex with blood concentrations of heavy metals in teenagers. In addition, factors such as a shared family environment may have an association. We analyzed data from the Korean National Health and Nutrition Examination Survey (KNHANES, 2010-2013) to determine whether blood levels of heavy metals differ by risk factors such as age, sex, and shared family environment in a representative sample of teenagers. METHODS This study used data obtained in the KNHANES 2010-2013, which had a rolling sampling design that involved a complex, stratified, multistage, probability-cluster survey of a representative sample of the non-institutionalized civilian population in South Korea. Our cross-sectional analysis was restricted to teenagers and their parents who completed the health examination survey, and for whom blood measurements of cadmium, lead, and mercury were available. The final analytical sample consisted of 1585 teenagers, and 376 fathers and 399 mothers who provided measurements of blood heavy metal concentrations. RESULTS Male teenagers had greater blood levels of lead and mercury, but sex had no association with blood cadmium level. There were age-related increases in blood cadmium, but blood lead decreased with age, and age had little association with blood mercury. The concentrations of cadmium and mercury declined from 2010 to 2013. The blood concentrations of lead, cadmium, and mercury in teenagers were positively associated with the levels in their parents after adjustment for covariates. CONCLUSION Our results show that blood heavy metal concentrations differ by risk factors such as age, sex, and shared family environment in teenagers.
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Affiliation(s)
- Nam-Soo Kim
- Institute of Occupational and Environmental Medicine, Soonchunhyang University, Asan, South Korea
| | - Jaeouk Ahn
- Department of Medical IT Engineering, Soonchunhyang University, Asan, South Korea
| | - Byung-Kook Lee
- Department of Preventive Medicine, Soonchunhyang University, Asan, South Korea
| | - Jungsun Park
- Department of Occupational Health, Catholic University of Daegu, Gyeongsan, South Korea
| | - Yangho Kim
- Department of Occupational and Environmental Medicine, Ulsan University Hospital, University of Ulsan College of Medicine, Ulsan, South Korea.
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Eom SY, Hwang MS, Lim JA, Choi BS, Kwon HJ, Park JD, Kim YD, Kim H. Exome-wide association study identifies genetic polymorphisms of C12orf51, MYL2, and ALDH2 associated with blood lead levels in the general Korean population. Environ Health 2017; 16:11. [PMID: 28212632 PMCID: PMC5316181 DOI: 10.1186/s12940-017-0220-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2016] [Accepted: 02/14/2017] [Indexed: 06/06/2023]
Abstract
BACKGROUND Lead (Pb) is a ubiquitous toxic metal present in the environment that poses adverse health effects to humans. Inter-individual variation in blood Pb levels is affected by various factors, including genetic makeup. However, limited data are available on the association between genetic variation and blood Pb levels. The purpose of this study was to identify the genetic markers associated with blood Pb levels in the Korean population. METHODS The study subjects consisted of 1,483 healthy adults with no history of occupational exposure to Pb. We measured blood Pb levels and calculated probable daily intake of Pb according to dietary data collected using 24-hour recall. We conducted exome-wide association screening using Illumina Human Exome-12v1.2 platform (n = 500) and a replication analysis using VeraCode Goldengate assay (n = 1,483). RESULTS Among the 244,770 single nucleotide polymorphisms (SNPs) tested, 12 SNPs associated with blood Pb level were identified, with suggestive significance level (P < 1 × 10-4). In the Goldengate assay for replication, three SNPs (C12orf51 rs11066280, MYL2 rs12229654, and ALDH2 rs671) were associated with statistically suggestively significant differences in blood Pb levels. When stratified by drinking status, a potential association of C12orf51 rs11066280, MYL2 rs12229654, and ALDH2 rs671 with blood Pb level was observed only in drinkers. A marginally significant gene-environment interaction between ALDH2 rs671 and alcohol consumption was observed in relation to blood Pb levels. The effects of the three suggestively significant SNPs on blood Pb levels was dependent on daily calcium intake amounts. CONCLUSIONS This exome-wide association study indicated that C12orf51 rs11066280, MYL2 rs12229654, and ALDH2 rs671 polymorphisms are linked to blood Pb levels in the Korean population. Our results suggest that these three SNPs are involved in the determination of Pb levels in Koreans via the regulation of alcohol drinking behavior, and that their negative effects may be compensated by appropriate calcium intake.
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Affiliation(s)
- Sang-Yong Eom
- Department of Preventive Medicine, College of Medicine, Chungbuk National University, 1 Chungdae-Ro, Seowon-Gu, Cheongju, Chungbuk 28644 Korea
| | - Myung Sil Hwang
- Food Risk Analysis Division, National Institute of Food and Drug Safety Evaluation, 187 Osongsaengmyeong 2-Ro, Heungdeok-Gu, Cheongju 28159 Korea
| | - Ji-Ae Lim
- Department of Preventive Medicine, Dankook University College of Medicine, 119 Dandae-Ro, Dongnam-Gu, Cheonan, Chungnam 31116 Korea
| | - Byung-Sun Choi
- Department of Preventive Medicine, Chung-Ang University College of Medicine, 84 Heukseok-Ro, Dongjak-Gu, Seoul, 06974 Korea
| | - Ho-Jang Kwon
- Department of Preventive Medicine, Dankook University College of Medicine, 119 Dandae-Ro, Dongnam-Gu, Cheonan, Chungnam 31116 Korea
| | - Jung-Duck Park
- Department of Preventive Medicine, Chung-Ang University College of Medicine, 84 Heukseok-Ro, Dongjak-Gu, Seoul, 06974 Korea
| | - Yong-Dae Kim
- Department of Preventive Medicine, College of Medicine, Chungbuk National University, 1 Chungdae-Ro, Seowon-Gu, Cheongju, Chungbuk 28644 Korea
| | - Heon Kim
- Department of Preventive Medicine, College of Medicine, Chungbuk National University, 1 Chungdae-Ro, Seowon-Gu, Cheongju, Chungbuk 28644 Korea
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15
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Genetics of the human placenta: implications for toxicokinetics. Arch Toxicol 2016; 90:2563-2581. [DOI: 10.1007/s00204-016-1816-6] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2016] [Accepted: 08/04/2016] [Indexed: 10/21/2022]
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16
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Barrett JR. Different People, Different Outcomes: Assessing Genetic Susceptibility to Lead Exposures. ENVIRONMENTAL HEALTH PERSPECTIVES 2016; 124:A131. [PMID: 27479021 PMCID: PMC4937845 DOI: 10.1289/ehp.124-a131] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
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Zhou S, Morozova TV, Hussain YN, Luoma SE, McCoy L, Yamamoto A, Mackay TF, Anholt RR. The Genetic Basis for Variation in Sensitivity to Lead Toxicity in Drosophila melanogaster. ENVIRONMENTAL HEALTH PERSPECTIVES 2016; 124:1062-70. [PMID: 26859824 PMCID: PMC4937873 DOI: 10.1289/ehp.1510513] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/20/2015] [Revised: 10/19/2015] [Accepted: 01/21/2016] [Indexed: 05/05/2023]
Abstract
BACKGROUND Lead toxicity presents a worldwide health problem, especially due to its adverse effects on cognitive development in children. However, identifying genes that give rise to individual variation in susceptibility to lead toxicity is challenging in human populations. OBJECTIVES Our goal was to use Drosophila melanogaster to identify evolutionarily conserved candidate genes associated with individual variation in susceptibility to lead exposure. METHODS To identify candidate genes associated with variation in susceptibility to lead toxicity, we measured effects of lead exposure on development time, viability and adult activity in the Drosophila melanogaster Genetic Reference Panel (DGRP) and performed genome-wide association analyses to identify candidate genes. We used mutants to assess functional causality of candidate genes and constructed a genetic network associated with variation in sensitivity to lead exposure, on which we could superimpose human orthologs. RESULTS We found substantial heritabilities for all three traits and identified candidate genes associated with variation in susceptibility to lead exposure for each phenotype. The genetic architectures that determine variation in sensitivity to lead exposure are highly polygenic. Gene ontology and network analyses showed enrichment of genes associated with early development and function of the nervous system. CONCLUSIONS Drosophila melanogaster presents an advantageous model to study the genetic underpinnings of variation in susceptibility to lead toxicity. Evolutionary conservation of cellular pathways that respond to toxic exposure allows predictions regarding orthologous genes and pathways across phyla. Thus, studies in the D. melanogaster model system can identify candidate susceptibility genes to guide subsequent studies in human populations. CITATION Zhou S, Morozova TV, Hussain YN, Luoma SE, McCoy L, Yamamoto A, Mackay TF, Anholt RR. 2016. The genetic basis for variation in sensitivity to lead toxicity in Drosophila melanogaster. Environ Health Perspect 124:1062-1070; http://dx.doi.org/10.1289/ehp.1510513.
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Affiliation(s)
- Shanshan Zhou
- W.M. Keck Center for Behavioral Biology, Program in Genetics, and
- Department of Biological Sciences, North Carolina State University, Raleigh, North Carolina, USA
| | - Tatiana V. Morozova
- W.M. Keck Center for Behavioral Biology, Program in Genetics, and
- Department of Biological Sciences, North Carolina State University, Raleigh, North Carolina, USA
| | - Yasmeen N. Hussain
- W.M. Keck Center for Behavioral Biology, Program in Genetics, and
- Department of Biological Sciences, North Carolina State University, Raleigh, North Carolina, USA
- Department of Biochemistry and Physiology, School of Bioscience and Medicine, Faculty of Health and Medical Sciences, University of Surrey, Guildford, Surrey, United Kingdom
| | - Sarah E. Luoma
- W.M. Keck Center for Behavioral Biology, Program in Genetics, and
- Department of Biological Sciences, North Carolina State University, Raleigh, North Carolina, USA
| | - Lenovia McCoy
- W.M. Keck Center for Behavioral Biology, Program in Genetics, and
- Department of Biological Sciences, North Carolina State University, Raleigh, North Carolina, USA
| | - Akihiko Yamamoto
- W.M. Keck Center for Behavioral Biology, Program in Genetics, and
- Department of Biological Sciences, North Carolina State University, Raleigh, North Carolina, USA
| | - Trudy F.C. Mackay
- W.M. Keck Center for Behavioral Biology, Program in Genetics, and
- Department of Biological Sciences, North Carolina State University, Raleigh, North Carolina, USA
| | - Robert R.H. Anholt
- W.M. Keck Center for Behavioral Biology, Program in Genetics, and
- Department of Biological Sciences, North Carolina State University, Raleigh, North Carolina, USA
- Address correspondence to R.R.H. Anholt, W.M. Keck Center for Behavioral Biology, 3510 Thomas Hall, North Carolina State University, Campus Box 7614, Raleigh, NC 27695-7614 USA. Telephone: (919) 515-1173. E-mail:
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Nigg JT, Elmore AL, Natarajan N, Friderici KH, Nikolas MA. Variation in an Iron Metabolism Gene Moderates the Association Between Blood Lead Levels and Attention-Deficit/Hyperactivity Disorder in Children. Psychol Sci 2015; 27:257-69. [PMID: 26710823 DOI: 10.1177/0956797615618365] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2015] [Accepted: 10/29/2015] [Indexed: 12/12/2022] Open
Abstract
Although attention-deficit/hyperactivity disorder (ADHD) is a heritable neurodevelopmental condition, there is also considerable scientific and public interest in environmental modulators of its etiology. Exposure to neurotoxins is one potential source of perturbation of neural, and hence psychological, development. Exposure to lead in particular has been widely investigated and is correlated with neurodevelopmental outcomes, including ADHD. To investigate whether this effect is likely to be causal, we used a Mendelian randomization design with a functional gene variant. In a case-control study, we examined the association between ADHD symptoms in children and blood lead level as moderated by variants in the hemochromatosis (HFE) gene. The HFE gene regulates iron uptake and secondarily modulates lead metabolism. Statistical moderation was observed: The magnitude of the association of blood lead with symptoms of ADHD was altered by functional HFE genotype, which is consistent with a causal hypothesis.
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Affiliation(s)
- Joel T Nigg
- Department of Psychiatry, Oregon Health & Science University Department of Behavioral Neuroscience, Oregon Health & Science University
| | - Alexis L Elmore
- Department of Psychological & Brain Sciences, University of Iowa
| | - Neil Natarajan
- Department of Psychiatry, Oregon Health & Science University
| | - Karen H Friderici
- Department of Microbiology and Molecular Genetics, Michigan State University
| | - Molly A Nikolas
- Department of Microbiology and Molecular Genetics, Michigan State University
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Abstract
Cation-coupled HCO3(-) transport was initially identified in the mid-1970s when pioneering studies showed that acid extrusion from cells is stimulated by CO2/HCO3(-) and associated with Na(+) and Cl(-) movement. The first Na(+)-coupled bicarbonate transporter (NCBT) was expression-cloned in the late 1990s. There are currently five mammalian NCBTs in the SLC4-family: the electrogenic Na,HCO3-cotransporters NBCe1 and NBCe2 (SLC4A4 and SLC4A5 gene products); the electroneutral Na,HCO3-cotransporter NBCn1 (SLC4A7 gene product); the Na(+)-driven Cl,HCO3-exchanger NDCBE (SLC4A8 gene product); and NBCn2/NCBE (SLC4A10 gene product), which has been characterized as an electroneutral Na,HCO3-cotransporter or a Na(+)-driven Cl,HCO3-exchanger. Despite the similarity in amino acid sequence and predicted structure among the NCBTs of the SLC4-family, they exhibit distinct differences in ion dependency, transport function, pharmacological properties, and interactions with other proteins. In epithelia, NCBTs are involved in transcellular movement of acid-base equivalents and intracellular pH control. In nonepithelial tissues, NCBTs contribute to intracellular pH regulation; and hence, they are crucial for diverse tissue functions including neuronal discharge, sensory neuron development, performance of the heart, and vascular tone regulation. The function and expression levels of the NCBTs are generally sensitive to intracellular and systemic pH. Animal models have revealed pathophysiological roles of the transporters in disease states including metabolic acidosis, hypertension, visual defects, and epileptic seizures. Studies are being conducted to understand the physiological consequences of genetic polymorphisms in the SLC4-members, which are associated with cancer, hypertension, and drug addiction. Here, we describe the current knowledge regarding the function, structure, and regulation of the mammalian cation-coupled HCO3(-) transporters of the SLC4-family.
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Affiliation(s)
- Christian Aalkjaer
- Department of Biomedicine, and the Water and Salt Research Center, Aarhus University, Aarhus, Denmark; Department of Physiology, Emory University School of Medicine, Atlanta, USA
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Liu C, Huo X, Lin P, Zhang Y, Li W, Xu X. Association between blood erythrocyte lead concentrations and hemoglobin levels in preschool children. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2015; 22:9233-40. [PMID: 25588596 DOI: 10.1007/s11356-014-3992-3] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/20/2014] [Accepted: 12/12/2014] [Indexed: 02/05/2023]
Abstract
Despite decades of intensive research, lead (Pb) toxicity still remains one of the most frequently investigated subjects in environmental health. Whole blood lead (BPb) is usually used to evaluate Pb exposure for both screening and clinical diagnosis. However, it is generally recognized that BPb is not a sensitive biomarker for Pb exposure in hematological studies. Considering hematocrit (HCT) variation in different situations, HCT-adjusted BPb or erythrocyte Pb (EPb) may be more relevant when evaluating the hematotoxicity of blood Pb. Data collected from 855 preschool children, 3-7 years of age, allowed us to examine the relationship between EPb and hemoglobin (Hb) levels. Multivariate linear regression was performed to determine the significance of EPb as predictor of Hb after covariate adjustment; then, mean differences of Hb levels between quartiles of EPb and BPb (1st quartile as reference) were determined using ANOVA followed by Student's t test. The dose-response curve between EPb and HCT was plotted using locally weighted scatterplot smoothing (LOWESS) method. A doubling of EPb was associated with a 2.44 g/L decrease in Hb level. Compared to the 1st quartile group of EPb, the 3rd and 4th quartile groups showed significant decreases in Hb levels (3.01 and 3.97 g/L, respectively). Compared to the 1st quartile group of BPb, the 2nd quartile group showed a decrease in Hb levels (0.63 g/L), while the 3rd and 4th quartile groups showed increases in Hb levels (0.78 and 1.45 g/L, respectively). Increased EPb levels are significantly associated with decreased Hb levels in preschool children. HCT must be taken into consideration in investigating the hematological effects of Pb. Compared to BPb, EPb or HCT-adjusted BPb appear as a more effective biomarker to interpret the hematotoxicity of lead. Furthermore, blood erythrocytes are not only a repository of Pb but also a primary target of its toxicity.
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Affiliation(s)
- Chunhua Liu
- Laboratory of Environmental Medicine and Developmental Toxicology, Provincial Key Laboratory of Infectious Diseases and Molecular Immunopathology, Shantou University Medical College, 22 Xinling Rd., Shantou, 515041, Guangdong, China
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Warrington NM, Zhu G, Dy V, Heath AC, Madden PAF, Hemani G, Kemp JP, Mcmahon G, St Pourcain B, Timpson NJ, Taylor CM, Golding J, Lawlor DA, Steer C, Montgomery GW, Martin NG, Davey Smith G, Evans DM, Whitfield JB. Genome-wide association study of blood lead shows multiple associations near ALAD. Hum Mol Genet 2015; 24:3871-9. [PMID: 25820613 DOI: 10.1093/hmg/ddv112] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2014] [Accepted: 03/24/2015] [Indexed: 01/30/2023] Open
Abstract
Exposure to high levels of environmental lead, or biomarker evidence of high body lead content, is associated with anaemia, developmental and neurological deficits in children, and increased mortality in adults. Adverse effects of lead still occur despite substantial reduction in environmental exposure. There is genetic variation between individuals in blood lead concentration but the polymorphisms contributing to this have not been defined. We measured blood or erythrocyte lead content, and carried out genome-wide association analysis, on population-based cohorts of adult volunteers from Australia and UK (N = 5433). Samples from Australia were collected in two studies, in 1993-1996 and 2002-2005 and from UK in 1991-1992. One locus, at ALAD on chromosome 9, showed consistent association with blood lead across countries and evidence for multiple independent allelic effects. The most significant single nucleotide polymorphism (SNP), rs1805313 (P = 3.91 × 10(-14) for lead concentration in a meta-analysis of all data), is known to have effects on ALAD expression in blood cells but other SNPs affecting ALAD expression did not affect blood lead. Variants at 12 other loci, including ABO, showed suggestive associations (5 × 10(-6) > P > 5 × 10(-8)). Identification of genetic polymorphisms affecting blood lead reinforces the view that genetic factors, as well as environmental ones, are important in determining blood lead levels. The ways in which ALAD variation affects lead uptake or distribution are still to be determined.
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Affiliation(s)
- Nicole M Warrington
- University of Queensland Diamantina Institute, Translational Research Institute, Brisbane, Australia
| | - Gu Zhu
- QIMR Berghofer Medical Research Institute, Locked Bag 2000, Royal Brisbane Hospital, Queensland 4029, Australia
| | - Veronica Dy
- Royal Prince Alfred Hospital, Sydney, Australia
| | - Andrew C Heath
- Department of Psychiatry, Washington University School of Medicine, St Louis, MO, USA
| | - Pamela A F Madden
- Department of Psychiatry, Washington University School of Medicine, St Louis, MO, USA
| | - Gibran Hemani
- MRC Integrative Epidemiology Unit, School of Social and Community Medicine and
| | - John P Kemp
- University of Queensland Diamantina Institute, Translational Research Institute, Brisbane, Australia, MRC Integrative Epidemiology Unit, School of Social and Community Medicine and
| | - George Mcmahon
- MRC Integrative Epidemiology Unit, School of Social and Community Medicine and
| | | | - Nicholas J Timpson
- MRC Integrative Epidemiology Unit, School of Social and Community Medicine and
| | - Caroline M Taylor
- Centre for Child and Adolescent Health, School of Social and Community Medicine, University of Bristol, Bristol, UK
| | | | - Debbie A Lawlor
- MRC Integrative Epidemiology Unit, School of Social and Community Medicine and
| | - Colin Steer
- Centre for Child and Adolescent Health, School of Social and Community Medicine, University of Bristol, Bristol, UK
| | - Grant W Montgomery
- QIMR Berghofer Medical Research Institute, Locked Bag 2000, Royal Brisbane Hospital, Queensland 4029, Australia
| | - Nicholas G Martin
- QIMR Berghofer Medical Research Institute, Locked Bag 2000, Royal Brisbane Hospital, Queensland 4029, Australia
| | - George Davey Smith
- MRC Integrative Epidemiology Unit, School of Social and Community Medicine and
| | - David M Evans
- University of Queensland Diamantina Institute, Translational Research Institute, Brisbane, Australia, MRC Integrative Epidemiology Unit, School of Social and Community Medicine and
| | - John B Whitfield
- QIMR Berghofer Medical Research Institute, Locked Bag 2000, Royal Brisbane Hospital, Queensland 4029, Australia,
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Barrdahl M, Canzian F, Joshi AD, Travis RC, Chang-Claude J, Auer PL, Gapstur SM, Gaudet M, Diver WR, Henderson BE, Haiman CA, Schumacher FR, Le Marchand L, Berg CD, Chanock SJ, Hoover RN, Rudolph A, Ziegler RG, Giles GG, Baglietto L, Severi G, Hankinson SE, Lindström S, Willet W, Hunter DJ, Buring JE, Lee IM, Zhang S, Dossus L, Cox DG, Khaw KT, Lund E, Naccarati A, Peeters PH, Quirós JR, Riboli E, Sund M, Trichopoulos D, Prentice RL, Kraft P, Kaaks R, Campa D. Post-GWAS gene-environment interplay in breast cancer: results from the Breast and Prostate Cancer Cohort Consortium and a meta-analysis on 79,000 women. Hum Mol Genet 2014; 23:5260-70. [PMID: 24895409 PMCID: PMC4159150 DOI: 10.1093/hmg/ddu223] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2014] [Revised: 04/09/2014] [Accepted: 05/06/2014] [Indexed: 01/12/2023] Open
Abstract
We studied the interplay between 39 breast cancer (BC) risk SNPs and established BC risk (body mass index, height, age at menarche, parity, age at menopause, smoking, alcohol and family history of BC) and prognostic factors (TNM stage, tumor grade, tumor size, age at diagnosis, estrogen receptor status and progesterone receptor status) as joint determinants of BC risk. We used a nested case-control design within the National Cancer Institute's Breast and Prostate Cancer Cohort Consortium (BPC3), with 16 285 BC cases and 19 376 controls. We performed stratified analyses for both the risk and prognostic factors, testing for heterogeneity for the risk factors, and case-case comparisons for differential associations of polymorphisms by subgroups of the prognostic factors. We analyzed multiplicative interactions between the SNPs and the risk factors. Finally, we also performed a meta-analysis of the interaction ORs from BPC3 and the Breast Cancer Association Consortium. After correction for multiple testing, no significant interaction between the SNPs and the established risk factors in the BPC3 study was found. The meta-analysis showed a suggestive interaction between smoking status and SLC4A7-rs4973768 (Pinteraction = 8.84 × 10(-4)) which, although not significant after considering multiple comparison, has a plausible biological explanation. In conclusion, in this study of up to almost 79 000 women we can conclusively exclude any novel major interactions between genome-wide association studies hits and the epidemiologic risk factors taken into consideration, but we propose a suggestive interaction between smoking status and SLC4A7-rs4973768 that if further replicated could help our understanding in the etiology of BC.
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Affiliation(s)
| | - Federico Canzian
- Genomic Epidemiology Group, German Cancer Research Center (DKFZ), Heidelberg D-69120, Germany
| | - Amit D Joshi
- Department of Epidemiology, Harvard School of Public Health, Boston, MA 02115, USA
| | - Ruth C Travis
- Cancer Epidemiology Unit, University of Oxford, Oxford OX3 7LF, UK
| | | | - Paul L Auer
- Public Health Sciences Division, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA School of Public Health, University of Wisconsin, Milwaukee, WI 1240, USA
| | - Susan M Gapstur
- Department of Epidemiology, American Cancer Society, Atlanta, GA 30303, USA
| | - Mia Gaudet
- Department of Epidemiology, American Cancer Society, Atlanta, GA 30303, USA
| | - W Ryan Diver
- Department of Epidemiology, American Cancer Society, Atlanta, GA 30303, USA
| | - Brian E Henderson
- Department of Preventive Medicine, Keck School of Medicine, University of Southern California, Los Angeles, CA 90033, USA
| | - Christopher A Haiman
- Department of Preventive Medicine, Keck School of Medicine, University of Southern California, Los Angeles, CA 90033, USA
| | - Fredrick R Schumacher
- Department of Preventive Medicine, Keck School of Medicine, University of Southern California, Los Angeles, CA 90033, USA
| | | | - Christine D Berg
- Division of Cancer Epidemiology and Genetics, National Cancer Institute, Bethesda, MD 20892, USA
| | - Stephen J Chanock
- Division of Cancer Epidemiology and Genetics, National Cancer Institute, Bethesda, MD 20892, USA
| | - Robert N Hoover
- Division of Cancer Epidemiology and Genetics, National Cancer Institute, Bethesda, MD 20892, USA
| | | | - Regina G Ziegler
- Division of Cancer Epidemiology and Genetics, National Cancer Institute, Bethesda, MD 20892, USA
| | - Graham G Giles
- Cancer Epidemiology Centre Melbourne, Cancer Council Victoria, Carlton South, VIC 3004, Australia Centre for Molecular, Environmental, Genetic and Analytic Epidemiology, School of Population Health, The University of Melbourne, Melbourne, VIC 3010, Australia Faculty of Medicine, Monash University, Melbourne, VIC 3800, Australia
| | - Laura Baglietto
- Cancer Epidemiology Centre Melbourne, Cancer Council Victoria, Carlton South, VIC 3004, Australia Centre for Molecular, Environmental, Genetic and Analytic Epidemiology, School of Population Health, The University of Melbourne, Melbourne, VIC 3010, Australia
| | - Gianluca Severi
- Cancer Epidemiology Centre Melbourne, Cancer Council Victoria, Carlton South, VIC 3004, Australia Centre for Molecular, Environmental, Genetic and Analytic Epidemiology, School of Population Health, The University of Melbourne, Melbourne, VIC 3010, Australia
| | - Susan E Hankinson
- Department of Epidemiology, Harvard School of Public Health, Boston, MA 02115, USA Channing Division of Network Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA 02115, USA Division of Biostatistics and Epidemiology, University of Massachusetts, Amherst, MA 01003-9304, USA
| | - Sara Lindström
- Department of Epidemiology, Harvard School of Public Health, Boston, MA 02115, USA
| | - Walter Willet
- Department of Epidemiology, Harvard School of Public Health, Boston, MA 02115, USA
| | - David J Hunter
- Department of Epidemiology, Harvard School of Public Health, Boston, MA 02115, USA
| | - Julie E Buring
- Department of Epidemiology, Harvard School of Public Health, Boston, MA 02115, USA
| | - I-Min Lee
- Department of Epidemiology, Harvard School of Public Health, Boston, MA 02115, USA
| | - Shumin Zhang
- Department of Epidemiology, Harvard School of Public Health, Boston, MA 02115, USA
| | - Laure Dossus
- INSERM, Centre for Research in Epidemiology and Population Health, Institut Gustave Roussy, Villejuif F-94805, France Paris South University, Villejuif F-94807, France
| | - David G Cox
- School of Public Health, Imperial College London, London SW7 2AZ, UK Université de Lyon, Université Lyon 1, ISPB, Lyon F-69007, France INSERM U1052, CNRS UMR5286, Centre de Recherche en Cancérologie de Lyon, Lyon F-69008, France Centre Léon Bérard, Lyon F-69008, France
| | - Kay-Tee Khaw
- Department of Public Health and Primary Care, School of Clinical Medicine, University of Cambridge, Cambridge CB2 0SP, UK
| | - Eiliv Lund
- Institute of Community Medicine, University of Tromsø, Tromsø N-9037, Norway
| | - Alessio Naccarati
- Molecular and Genetic Epidemiology Unit, Human Genetics Foundation Torino, Torino I-10126, Italy
| | - Petra H Peeters
- School of Public Health, Imperial College London, London SW7 2AZ, UK Department of Epidemiology, Julius Center for Health Sciences and Primary Care, University Medical Center, Utrecht 3584 CS, The Netherlands
| | | | - Elio Riboli
- School of Public Health, Imperial College London, London SW7 2AZ, UK
| | - Malin Sund
- Department of Surgical and Perioperative Sciences, Surgery, Umeå University, Umeå S-90185, Sweden
| | - Dimitrios Trichopoulos
- Department of Epidemiology, Harvard School of Public Health, Boston, MA 02115, USA Bureau of Epidemiologic Research, Academy of Athens, Athens 10679, Greece Hellenic Health Foundation, Athens 11527, Greece
| | - Ross L Prentice
- Public Health Sciences Division, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA
| | - Peter Kraft
- Department of Epidemiology, Harvard School of Public Health, Boston, MA 02115, USA
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The effect of the hemochromatosis (HFE) genotype on lead load and iron metabolism among lead smelter workers. PLoS One 2014; 9:e101537. [PMID: 24988074 PMCID: PMC4079697 DOI: 10.1371/journal.pone.0101537] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2014] [Accepted: 06/06/2014] [Indexed: 12/28/2022] Open
Abstract
Background Both an excess of toxic lead (Pb) and an essential iron disorder have been implicated in many diseases and public health problems. Iron metabolism genes, such as the hemochromatosis (HFE) gene, have been reported to be modifiers for lead absorption and storage. However, the HFE gene studies among the Asian population with occupationally high lead exposure are lacking. Objectives To explore the modifying effects of the HFE genotype (wild-type, H63D variant and C282Y variant) on the Pb load and iron metabolism among Asian Pb-workers with high occupational exposure. Methods Seven hundred and seventy-one employees from a lead smelter manufacturing company were tested to determine their Pb intoxication parameters, iron metabolic indexes and identify the HFE genotype. Descriptive and multivariate analyses were conducted. Results Forty-five H63D variant carriers and no C282Y variant carrier were found among the 771 subjects. Compared with subjects with the wild-type genotype, H63D variant carriers had higher blood lead levels, even after controlling for factors such as age, sex, marriage, education, smoking and lead exposure levels. Multivariate analyses also showed that the H63D genotype modifies the associations between the blood lead levels and the body iron burden/transferrin. Conclusions No C282Y variant was found in this Asian population. The H63D genotype modified the association between the lead and iron metabolism such that increased blood lead is associated with a higher body iron content or a lower transferrin in the H63D variant. It is indicated that H63D variant carriers may be a potentially highly vulnerable sub-population if they are exposed to high lead levels occupationally.
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Kim J, Lee Y, Yang M. Environmental exposure to lead (Pb) and variations in its susceptibility. JOURNAL OF ENVIRONMENTAL SCIENCE AND HEALTH. PART C, ENVIRONMENTAL CARCINOGENESIS & ECOTOXICOLOGY REVIEWS 2014; 32:159-85. [PMID: 24875442 DOI: 10.1080/10590501.2014.907461] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
Based on exposure frequency and intrinsic toxicity, lead (Pb) ranks one of the highest priority toxic materials. Continuous regulation of environmental Pb exposure has contributed to dramatically diminished exposure levels of Pb, for example, blood level of Pb. However, the safety level of Pb is not established, as low-level exposure to Pb still shows severe toxicity in high susceptible population and late onset of some diseases from early exposure. In the present study, we focused on food-borne Pb exposure and found broad variations in Pb exposure levels via food among countries. In addition, there are genetic or ethnical variations in Pb-targeted and protective genes. Moreover, various epigenetic alterations were induced by Pb poisoning. Therefore, we suggest a systemic approach including governmental (public) and individual prevention from Pb exposure with continuous biological monitoring and genetic or epigenetic consideration.
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Affiliation(s)
- Jina Kim
- a Research Center for Cell Fate Control, College of Pharmacy , Sookmyung Women's University , Seoul , Republic of Korea
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25
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Evans DM, Zhu G, Dy V, Heath AC, Madden PAF, Kemp JP, McMahon G, St Pourcain B, Timpson NJ, Golding J, Lawlor DA, Steer C, Montgomery GW, Martin NG, Smith GD, Whitfield JB. Genome-wide association study identifies loci affecting blood copper, selenium and zinc. Hum Mol Genet 2013; 22:3998-4006. [PMID: 23720494 PMCID: PMC3766178 DOI: 10.1093/hmg/ddt239] [Citation(s) in RCA: 120] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2013] [Revised: 05/06/2013] [Accepted: 05/21/2013] [Indexed: 11/14/2022] Open
Abstract
Genetic variation affecting absorption, distribution or excretion of essential trace elements may lead to health effects related to sub-clinical deficiency. We have tested for allelic effects of single-nucleotide polymorphisms (SNPs) on blood copper, selenium and zinc in a genome-wide association study using two adult cohorts from Australia and the UK. Participants were recruited in Australia from twins and their families and in the UK from pregnant women. We measured erythrocyte Cu, Se and Zn (Australian samples) or whole blood Se (UK samples) using inductively coupled plasma mass spectrometry. Genotyping was performed with Illumina chips and > 2.5 m SNPs were imputed from HapMap data. Genome-wide significant associations were found for each element. For Cu, there were two loci on chromosome 1 (most significant SNPs rs1175550, P = 5.03 × 10(-10), and rs2769264, P = 2.63 × 10(-20)); for Se, a locus on chromosome 5 was significant in both cohorts (combined P = 9.40 × 10(-28) at rs921943); and for Zn three loci on chromosomes 8, 15 and X showed significant results (rs1532423, P = 6.40 × 10(-12); rs2120019, P = 1.55 × 10(-18); and rs4826508, P = 1.40 × 10(-12), respectively). The Se locus covers three genes involved in metabolism of sulphur-containing amino acids and potentially of the analogous Se compounds; the chromosome 8 locus for Zn contains multiple genes for the Zn-containing enzyme carbonic anhydrase. Where potentially relevant genes were identified, they relate to metabolism of the element (Se) or to the presence at high concentration of a metal-containing protein (Cu).
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Affiliation(s)
- David M. Evans
- MRC Centre for Causal Analyses in Translational Epidemiology
- School of Social and Community Medicine and
| | - Gu Zhu
- Queensland Institute of Medical Research, Genetic Epidemiology, Locked Bag 2000 and
| | - Veronica Dy
- Royal Prince Alfred Hospital, Sydney, Australia
| | - Andrew C. Heath
- Department of Psychiatry, Washington University School of Medicine, St Louis, MO, USA
| | - Pamela A. F. Madden
- Department of Psychiatry, Washington University School of Medicine, St Louis, MO, USA
| | - John P. Kemp
- MRC Centre for Causal Analyses in Translational Epidemiology
- School of Social and Community Medicine and
| | - George McMahon
- MRC Centre for Causal Analyses in Translational Epidemiology
- School of Social and Community Medicine and
| | | | - Nicholas J. Timpson
- MRC Centre for Causal Analyses in Translational Epidemiology
- School of Social and Community Medicine and
| | - Jean Golding
- MRC Centre for Causal Analyses in Translational Epidemiology
- School of Social and Community Medicine and
| | - Debbie A. Lawlor
- MRC Centre for Causal Analyses in Translational Epidemiology
- School of Social and Community Medicine and
| | - Colin Steer
- Centre for Child and Adolescent Health, School of Social and Community Medicine, University of Bristol, Bristol, UK
| | - Grant W. Montgomery
- Queensland Institute of Medical Research, Molecular Epidemiology, Locked Bag 2000, Royal Brisbane Hospital, Herston, QLD 4029, Australia
| | - Nicholas G. Martin
- Queensland Institute of Medical Research, Genetic Epidemiology, Locked Bag 2000 and
| | - George Davey Smith
- MRC Centre for Causal Analyses in Translational Epidemiology
- School of Social and Community Medicine and
| | - John B. Whitfield
- Queensland Institute of Medical Research, Genetic Epidemiology, Locked Bag 2000 and
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26
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Kelsall LM, de Gooyer TE, Carey M, Vaughan L, Ansari Z. Blood lead levels in the adult Victorian population: results from the Victorian Health Monitor. Aust N Z J Public Health 2013; 37:233-7. [DOI: 10.1111/1753-6405.12064] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
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27
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Parker MD, Boron WF. The divergence, actions, roles, and relatives of sodium-coupled bicarbonate transporters. Physiol Rev 2013; 93:803-959. [PMID: 23589833 PMCID: PMC3768104 DOI: 10.1152/physrev.00023.2012] [Citation(s) in RCA: 196] [Impact Index Per Article: 17.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
The mammalian Slc4 (Solute carrier 4) family of transporters is a functionally diverse group of 10 multi-spanning membrane proteins that includes three Cl-HCO3 exchangers (AE1-3), five Na(+)-coupled HCO3(-) transporters (NCBTs), and two other unusual members (AE4, BTR1). In this review, we mainly focus on the five mammalian NCBTs-NBCe1, NBCe2, NBCn1, NDCBE, and NBCn2. Each plays a specialized role in maintaining intracellular pH and, by contributing to the movement of HCO3(-) across epithelia, in maintaining whole-body pH and otherwise contributing to epithelial transport. Disruptions involving NCBT genes are linked to blindness, deafness, proximal renal tubular acidosis, mental retardation, and epilepsy. We also review AE1-3, AE4, and BTR1, addressing their relevance to the study of NCBTs. This review draws together recent advances in our understanding of the phylogenetic origins and physiological relevance of NCBTs and their progenitors. Underlying these advances is progress in such diverse disciplines as physiology, molecular biology, genetics, immunocytochemistry, proteomics, and structural biology. This review highlights the key similarities and differences between individual NCBTs and the genes that encode them and also clarifies the sometimes confusing NCBT nomenclature.
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Affiliation(s)
- Mark D Parker
- Dept. of Physiology and Biophysics, Case Western Reserve University School of Medicine, 10900 Euclid Ave., Cleveland, OH 44106-4970, USA.
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28
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Gundacker C, Gencik M, Hengstschläger M. The relevance of the individual genetic background for the toxicokinetics of two significant neurodevelopmental toxicants: mercury and lead. Mutat Res 2010; 705:130-140. [PMID: 20601101 DOI: 10.1016/j.mrrev.2010.06.003] [Citation(s) in RCA: 98] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2010] [Revised: 06/07/2010] [Accepted: 06/10/2010] [Indexed: 11/25/2022]
Abstract
The heavy metals mercury and lead are well-known and significant developmental neurotoxicants. This review summarizes the genetic factors that modify their toxicokinetics. Understanding toxicokinetics (uptake, biotransformation, distribution, and elimination processes) is a key precondition to understanding the individual health risks associated with exposure. We selected candidate susceptibility genes when evidence was available for (1) genes/proteins playing a significant role in mercury and lead toxicokinetics, (2) gene expression/protein activity being induced by these metals, and (3) mercury and lead toxicokinetics being affected by gene knockout/knockdown or (4) by functional gene polymorphisms. The genetic background is far better known for mercury than for lead toxicokinetics. Involved are genes encoding L-type amino acid transporters, organic anion transporters, glutathione (GSH)-related enzymes, metallothioneins, and transporters of the ABC family. Certain gene variants can influence mercury toxicokinetics, potentially explaining part of the variable susceptibility to mercury toxicity. Delta-aminolevulinic acid dehydratase (ALAD), vitamin D receptor (VDR) and hemochromatosis (HFE) gene variants are the only well-established susceptibility markers of lead toxicity in humans. Many gaps remain in our knowledge about the functional genomics of this issue. This calls for studies to detect functional gene polymorphisms related to mercury- and lead-associated disease phenotypes, to demonstrate the impact of functional polymorphisms and gene knockout/knockdown in relation to toxicity, to confirm the in vivo relevance of genetic variation, and to examine gene-gene interactions on the respective toxicokinetics. Another crucial aspect is knowledge on the maternal-fetal genetic background, which modulates fetal exposure to these neurotoxicants. To completely define the genetically susceptible risk groups, research is also needed on the genes/proteins involved in the toxicodynamics, i.e., in the mechanisms causing adverse effects in the brain. Studies relating the toxicogenetics to neurodevelopmental disorders are lacking (mercury) or very scarce (lead). Thus, the extent of variability in susceptibility to heavy metal-associated neurological outcomes is poorly characterized.
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Affiliation(s)
- Claudia Gundacker
- Institute of Medical Genetics, Medical University of Vienna, Währinger Strasse 10, A-1090 Vienna, Austria.
| | - Martin Gencik
- Praxis fur Humangenetik, Brünnlbadgasse 15, A-1090 Vienna, Austria
| | - Markus Hengstschläger
- Institute of Medical Genetics, Medical University of Vienna, Währinger Strasse 10, A-1090 Vienna, Austria
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29
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Whitfield JB, Dy V, McQuilty R, Zhu G, Heath AC, Montgomery GW, Martin NG. Genetic effects on toxic and essential elements in humans: arsenic, cadmium, copper, lead, mercury, selenium, and zinc in erythrocytes. ENVIRONMENTAL HEALTH PERSPECTIVES 2010; 118:776-82. [PMID: 20053595 PMCID: PMC2898853 DOI: 10.1289/ehp.0901541] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/05/2009] [Accepted: 01/05/2010] [Indexed: 05/20/2023]
Abstract
BACKGROUND AND OBJECTIVES An excess of toxic trace elements or a deficiency of essential ones has been implicated in many common diseases or public health problems, but little is known about causes of variation between people living within similar environments. We estimated effects of personal and socioeconomic characteristics on concentrations of arsenic (As), cadmium (Cd), copper (Cu), mercury (Hg), lead (Pb), selenium (Se), and zinc (Zn) in erythrocytes and tested for genetic effects using data from twin pairs. METHODS We used blood samples from 2,926 adult twins living in Australia (1,925 women and 1,001 men; 30-92 years of age) and determined element concentrations in erythrocytes by inductively coupled plasma-mass spectrometry. We assessed associations between element concentrations and personal and socioeconomic characteristics, as well as the sources of genetic and environmental variation and covariation in element concentrations. We evaluated the chromosomal locations of genes affecting these characteristics by linkage analysis in 501 dizygotic twin pairs. RESULTS Concentrations of Cu, Se, and Zn, and of As and Hg showed substantial correlations, concentrations of As and Hg due mainly to common genetic effects. Genetic linkage analysis showed significant linkage for Pb [chromosome 3, near SLC4A7 (solute carrier family 4, sodium bicarbonate cotransporter, member 7)] and suggestive linkage for Cd (chromosomes 2, 18, 20, and X), Hg (chromosome 5), Se (chromosomes 4 and 8), and Zn {chromosome 2, near SLC11A1 [solute carrier family 11 (proton-coupled divalent metal ion transporters)]}. CONCLUSIONS Although environmental exposure is a precondition for accumulation of toxic elements, individual characteristics and genetic factors are also important. Identification of the contributory genetic polymorphisms will improve our understanding of trace and toxic element uptake and distribution mechanisms.
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Affiliation(s)
- John B Whitfield
- Genetic Epidemiology Unit, Queensland Institute of Medical Research, Brisbane, Australia.
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30
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Shaik AP, Jamil K. Individual susceptibility and genotoxicity in workers exposed to hazardous materials like lead. JOURNAL OF HAZARDOUS MATERIALS 2009; 168:918-924. [PMID: 19327888 DOI: 10.1016/j.jhazmat.2009.02.129] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/21/2008] [Revised: 02/21/2009] [Accepted: 02/23/2009] [Indexed: 05/27/2023]
Abstract
The present study was undertaken to investigate lead-induced toxicity in occupationally exposed humans and to evaluate whether genetic damage can be correlated with the known clinical indicators of lead poisoning. For this purpose, genotoxicity biomarkers along with some clinical indices of lead poisoning were determined in blood samples of battery plant workers and compared with healthy control subjects. Workers had significantly increased chromosomal aberrations, micronuclei and DNA damage compared to the controls. Increased blood lead levels (BLLs), decreased hemoglobin, PCV and symptoms of lead poisoning were used as clinical indices of lead toxicity. In addition gene polymorphisms in ALAD and MGP gene were investigated and correlated with BLL and hemoglobin content. Our results showed no significant effects of the ALAD G177C polymorphism on BLL concentrations and BLL concentrations varied to levels much above the normal reference ranges independent of the genotype. Although, significance could not be achieved, ALAD 1-2/2-2 type subjects had numerically higher BLLs (76.2-89.1 microg/dl), compared to ALAD 1-1 volunteers (21.8-79.1 microg/dl). Similarly, this study also aimed to identify the relation of some SNPs with emphasis on lead toxicity and since MGP gene is an important biomarker associated with calcium metabolism; it was hypothesized that it may be associated with lead toxicity. However, we did not find any significant association of MGP T-138C and lead poisoning. Further studies on the role of gene polymorphisms over a larger population along with genotoxicity parameters and biochemical analyses may serve to understand lead toxicity.
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Affiliation(s)
- Abjal Pasha Shaik
- Department of Genetics, Bhagwan Mahavir Medical Research Centre, Masab Tank, Hyderabad, Andhra Pradesh, India
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31
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Bellinger DC. Late neurodevelopmental effects of early exposures to chemical contaminants: reducing uncertainty in epidemiological studies. Basic Clin Pharmacol Toxicol 2008; 102:237-44. [PMID: 18226079 DOI: 10.1111/j.1742-7843.2007.00164.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Early exposures to environmental chemicals are reliably associated with late neurotoxicities in children. However, substantial scatter of observations exists around the estimated dose-effect relationships. This variability has many potential sources, one of which is interindividual differences in susceptibility. Such differences imply that the long-term impacts of exposure will not the same for all individuals, but will vary depending on a variety of factors that might either aggravate or mitigate contaminant effects. These include co-exposures, genetic polymorphisms and characteristics of the social environment. The context dependence of contaminant effects has implications both for study designs and analytical approaches. In addition, a systems approach to understanding the associations among contaminant exposures, covariates and health outcomes is necessary.
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Affiliation(s)
- David C Bellinger
- Department of Neurology, Children's Hospital Boston, Boston, MA 02115, USA.
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