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Ham YH, Pan G, Chan HW, Chan W. LC-MS/MS Quantitation of Formaldehyde-Glutathione Conjugates as Biomarkers of Formaldehyde Exposure and Exposure-Induced Antioxidants: A New Look on an Old Topic. Chem Res Toxicol 2022; 35:858-866. [PMID: 35471961 DOI: 10.1021/acs.chemrestox.2c00027] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Humans are continuously exposed to formaldehyde via both endogenous and exogenous sources. Prolonged exposure to formaldehyde is associated with many human diseases, such as lung cancer and leukemia. The goal of this study is to develop biomarkers to measure formaldehyde exposure, which could be used to predict the risk of associated diseases. As glutathione (GSH) is well-known for its crucial role in the detoxification of a wide variety of xenobiotics, including formaldehyde, we rigorously quantitated in this study the conjugates formed when formaldehyde reacted with GSH using liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS) coupled with an isotope dilution method. The results showed for the first time that (S)-1-(((R)-2-amino-3-(carboxymethylamino)-3-oxopropylthio)methyl)-5-oxopyrrolidine-2-carboxylic acid (PGF) and thioproline-glycine (SPro-Gly) are major metabolites in both nonenzymatic reactions and formaldehyde-exposed human cells. In particular, over 35% of the formaldehyde from external sources was found to convert to SPro-Gly in the exposed cells. Interestingly, data showed that these exposure-induced adducts exhibited good antioxidative properties, which can protect cells from hydrogen peroxide mediated oxidative insult. It is anticipated that the findings of this study could shed light on developing PGF and SPro-Gly as dietary supplements and on the development of noninvasive methods to assess health risks associated with formaldehyde exposure.
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Affiliation(s)
- Yat-Hing Ham
- Department of Chemistry, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong
| | - Guanrui Pan
- Department of Chemistry, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong
| | - Ho Wai Chan
- Department of Chemistry, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong
| | - Wan Chan
- Department of Chemistry, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong
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2
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Thompson CM, Gentry R, Fitch S, Lu K, Clewell HJ. An updated mode of action and human relevance framework evaluation for Formaldehyde-Related nasal tumors. Crit Rev Toxicol 2021; 50:919-952. [PMID: 33599198 DOI: 10.1080/10408444.2020.1854679] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Formaldehyde is a reactive aldehyde naturally present in all plant and animal tissues and a critical component of the one-carbon metabolism pathway. It is also a high production volume chemical used in the manufacture of numerous products. Formaldehyde is also one of the most well-studied chemicals with respect to environmental fate, biology, and toxicology-including carcinogenic potential, and mode of action (MOA). In 2006, a published MOA for formaldehyde-induced nasal tumors in rats concluded that nasal tumors were most likely driven by cytotoxicity and regenerative cell proliferation, with possible contributions from direct genotoxicity. In the past 15 years, new research has better informed the MOA with the publication of in vivo genotoxicity assays, toxicogenomic analyses, and development of ultra-sensitive methods to measure endogenous and exogenous formaldehyde-induced DNA adducts. Herein, we review and update the MOA for nasal tumors, with particular emphasis on the numerous studies published since 2006. These new studies further underscore the involvement of cytotoxicity and regenerative cell proliferation, and further inform the genotoxic potential of inhaled formaldehyde. The data lend additional support for the use of mechanistic data for the derivation of toxicity criteria and/or scientifically supported approaches for low-dose extrapolation for the risk assessment of formaldehyde.
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Affiliation(s)
| | | | | | - Kun Lu
- Department of Environmental Sciences and Engineering, University of North Carolina at Chapel Hill, NC, USA
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3
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Folz JS, Patterson JA, Hanson AD, Fiehn O. Quantification of N 6-formylated lysine in bacterial protein digests using liquid chromatography/tandem mass spectrometry despite spontaneous formation and matrix effects. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2021; 35:e9019. [PMID: 33617101 DOI: 10.1002/rcm.9019] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/25/2020] [Revised: 12/04/2020] [Accepted: 12/06/2020] [Indexed: 06/12/2023]
Abstract
RATIONALE N6-Formyl lysine is a well-known modification of histones and other proteins. It can also be formed as a damaged product from direct formylation of free lysine and accompanied by other lysine derivatives such as acetylated or methylated forms. In relation to the activity of cellular repair enzymes in protein turnover and to lysine metabolism, it is important to accurately quantify the overall ratio of modified lysine to free lysine. METHODS N6-Formyl lysine was quantified using liquid chromatography/tandem mass spectrometry (LC/MS/MS) with data collected in a non-targeted manner using positive mode electrospray ionization on a Q-Exactive HF+ Orbitrap mass spectrometer. Studies were performed with lysine and deuterated lysine spiked into protein digests and solvents to investigate the extent of spontaneous formation and matrix effects of formation of N6-formyl lysine. RESULTS We show that N6-formyl lysine, N2-formyl lysine, N6-acetyl lysine, and N2-acetyl lysine are all formed spontaneously during sample preparation and LC/MS/MS analysis, which complicates quantification of these metabolites in biological samples. N6-Formyl lysine was spontaneously formed and correlated to the concentration of lysine. In the sample matrix of protein digests, 0.03% of lysine was spontaneously converted into N6-formyl lysine, and 0.005% of lysine was converted into N6-formyl lysine in pure run solvent. CONCLUSIONS Spontaneous formation of N6-formyl lysine, N6-acetyl lysine, N2-formyl lysine, and N2-acetyl lysine needs to be subtracted from biologically formed lysine modifications when quantifying these epimetabolites in biological samples.
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Affiliation(s)
- Jacob S Folz
- West Coast Metabolomics Center, University of California Davis, Davis, CA, USA
| | - Jenelle A Patterson
- Horticultural Sciences Department, University of Florida Gainesville, Gainesville, FL, USA
| | - Andrew D Hanson
- Horticultural Sciences Department, University of Florida Gainesville, Gainesville, FL, USA
| | - Oliver Fiehn
- West Coast Metabolomics Center, University of California Davis, Davis, CA, USA
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4
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Gentry R, Thompson CM, Franzen A, Salley J, Albertini R, Lu K, Greene T. Using mechanistic information to support evidence integration and synthesis: a case study with inhaled formaldehyde and leukemia. Crit Rev Toxicol 2021; 50:885-918. [PMID: 33538218 DOI: 10.1080/10408444.2020.1854678] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Formaldehyde is one of the most comprehensively studied chemicals, with over 30 years of research focused on understanding the development of cancer following inhalation. The causal conclusions regarding the potential for leukemia are largely based on the epidemiological literature, with little consideration of cancer bioassays, dosimetry studies, and mechanistic research, which challenge the biological plausibility of the disease. Recent reanalyzes of the epidemiological literature have also raised significant questions related to the purported associations between formaldehyde and leukemia. Because of this, considerable scientific debate and uncertainty remain on whether there is a causal association between formaldehyde inhalation exposure and leukemia. Further complexity in evaluating this association is related to the endogenous production of formaldehyde. Multiple modes of action (MOA) have been postulated for the development of leukemia following formaldehyde inhalation that includes unsupported hypotheses of direct or indirect toxicity to the target cell population. Herein, the available evidence relevant to evaluating the postulated MOAs for leukemia following formaldehyde inhalation exposure is organized in the IPCS MOA Framework. The integration of all the available evidence clearly highlights the limited amount of data that support any of the postulated MOAs and demonstrates a significant amount of research supporting the null hypothesis that there is no causal association between formaldehyde inhalation exposure and leukemia. These analyses result in a lack of confidence in any of the postulated MOAs, increasing confidence in the conclusion that there is a lack of biological plausibility for a causal association between formaldehyde inhalation exposure and leukemia.
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Affiliation(s)
| | | | | | | | - Richard Albertini
- Independent Consultant, Emeritus Professor, University of Vermont, Burlington, Vermont, USA
| | - Kun Lu
- Department of Environmental Sciences and Engineering, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
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5
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Pan G, Ham YH, Chan HW, Yao J, Chan W. LC-MS/MS Coupled with a Stable-Isotope Dilution Method for the Quantitation of Thioproline-Glycine: A Novel Metabolite in Formaldehyde- and Oxidative Stress-Exposed Cells. Chem Res Toxicol 2020; 33:1989-1996. [DOI: 10.1021/acs.chemrestox.0c00170] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Affiliation(s)
- Guanrui Pan
- Department of Chemistry, The Hong Kong University of Science and Technology, Clear Water
Bay, Kowloon, Hong Kong
| | - Yat-Hing Ham
- Department of Chemistry, The Hong Kong University of Science and Technology, Clear Water
Bay, Kowloon, Hong Kong
| | - Ho Wai Chan
- Department of Chemistry, The Hong Kong University of Science and Technology, Clear Water
Bay, Kowloon, Hong Kong
| | - Jing Yao
- Department of Mathematics, Southern University of Science and Technology, Shenzhen 518055, China
| | - Wan Chan
- Department of Chemistry, The Hong Kong University of Science and Technology, Clear Water
Bay, Kowloon, Hong Kong
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Rodríguez Mallón A, Javier González L, Encinosa Guzmán PE, Bechara GH, Sanches GS, Pousa S, Cabrera G, Cabrales A, Garay H, Mejías R, López Álvarez JR, Bello Soto Y, Almeida F, Guirola O, Rodríguez Fernández R, Fuentes Castillo A, Méndez L, Jiménez S, Licea-Navarro A, Portela M, Durán R, Estrada MP. Functional and Mass Spectrometric Evaluation of an Anti-Tick Antigen Based on the P0 Peptide Conjugated to Bm86 Protein. Pathogens 2020; 9:pathogens9060513. [PMID: 32630414 PMCID: PMC7350365 DOI: 10.3390/pathogens9060513] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2020] [Revised: 06/20/2020] [Accepted: 06/21/2020] [Indexed: 11/16/2022] Open
Abstract
A synthetic 20 amino acid peptide of the ribosomal protein P0 from ticks, when conjugated to keyhole limpet hemocyanin from Megathura crenulata and used as an immunogen against Rhipicephalus microplus and Rhipicephalus sanguineus s.l. species, has shown efficacies of around 90%. There is also experimental evidence of a high efficacy of this conjugate against Amblyomma mixtum and Ixodes ricinus species, which suggest that this antigen could be a good broad-spectrum anti-tick vaccine candidate. In this study, the P0 peptide (pP0) was chemically conjugated to Bm86 as a carrier protein. SDS-PAGE analysis of this conjugate demonstrated that it is highly heterogeneous in size, carrying from 1 to 18 molecules of pP0 per molecule of Bm86. Forty-nine out of the 54 lysine residues and the N-terminal end of Bm86 were found partially linked to pP0 by using LC-MS/MS analysis and the combination of four different softwares. Several post-translational modifications of Bm86 protein were also identified by mass spectrometry. High immunogenicity and efficacy were achieved when dogs and cattle were vaccinated with the pP0-Bm86 conjugate and challenged with R. sanguineus s.l. and R. microplus, respectively. These results encourage the development of this antigen with promising possibilities as an anti-tick vaccine.
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Affiliation(s)
- Alina Rodríguez Mallón
- Animal Biotechnology Department, Center for Genetic Engineering and Biotechnology (CIGB), Havana 10600, Cuba; (P.E.E.G.); (Y.B.S.); (M.P.E.)
- Correspondence: ; Tel.: +53-72504407
| | - Luis Javier González
- Mass Spectrometry Laboratory and GlycoLab, Department of Proteomics, CIGB, Havana 10600, Cuba; (L.J.G.); (S.P.); (G.C.); (F.A.)
| | - Pedro Enrique Encinosa Guzmán
- Animal Biotechnology Department, Center for Genetic Engineering and Biotechnology (CIGB), Havana 10600, Cuba; (P.E.E.G.); (Y.B.S.); (M.P.E.)
| | - Gervasio Henrique Bechara
- Programa de Pós-graduação em Ciência Animal, Pontifícia Universidade Católica do Paraná (PUCPR), Paraná 80215-901, Brazil; (G.H.B.); (G.S.S.)
- Departamento de Patologia Veterinária, Faculdade de Ciências Agrárias e Veterinárias, Universidade Estadual Paulista (FCAV-UNESP), São Paulo 14884-900, Brazil
| | - Gustavo Seron Sanches
- Programa de Pós-graduação em Ciência Animal, Pontifícia Universidade Católica do Paraná (PUCPR), Paraná 80215-901, Brazil; (G.H.B.); (G.S.S.)
- Departamento de Patologia Veterinária, Faculdade de Ciências Agrárias e Veterinárias, Universidade Estadual Paulista (FCAV-UNESP), São Paulo 14884-900, Brazil
| | - Satomy Pousa
- Mass Spectrometry Laboratory and GlycoLab, Department of Proteomics, CIGB, Havana 10600, Cuba; (L.J.G.); (S.P.); (G.C.); (F.A.)
| | - Gleysin Cabrera
- Mass Spectrometry Laboratory and GlycoLab, Department of Proteomics, CIGB, Havana 10600, Cuba; (L.J.G.); (S.P.); (G.C.); (F.A.)
| | - Ania Cabrales
- Synthetic Peptides Group, CIGB, Havana 10600, Cuba; (A.C.); (H.G.)
| | - Hilda Garay
- Synthetic Peptides Group, CIGB, Havana 10600, Cuba; (A.C.); (H.G.)
| | - Raúl Mejías
- Instituto de Ciencia Animal (ICA), San José de las Lajas 32700, Cuba; (R.M.); (J.R.L.Á.)
| | | | - Yamil Bello Soto
- Animal Biotechnology Department, Center for Genetic Engineering and Biotechnology (CIGB), Havana 10600, Cuba; (P.E.E.G.); (Y.B.S.); (M.P.E.)
| | - Fabiola Almeida
- Mass Spectrometry Laboratory and GlycoLab, Department of Proteomics, CIGB, Havana 10600, Cuba; (L.J.G.); (S.P.); (G.C.); (F.A.)
| | | | | | - Alier Fuentes Castillo
- National Laboratory for Parasitology, San Antonio de los Banos 32500, Cuba; (R.R.F.); (A.F.C.); (L.M.)
| | - Luis Méndez
- National Laboratory for Parasitology, San Antonio de los Banos 32500, Cuba; (R.R.F.); (A.F.C.); (L.M.)
| | - Samanta Jiménez
- Departamento de Innovación Biomédica, CICESE, Ensenada 22860, Mexico; (S.J.); (A.L.-N.)
| | - Alexei Licea-Navarro
- Departamento de Innovación Biomédica, CICESE, Ensenada 22860, Mexico; (S.J.); (A.L.-N.)
| | - Madelón Portela
- Unidad de Bioquímica y Proteómica Analítica, Institut Pasteur de Montevideo, Montevideo 11400, Uruguay; (M.P.); (R.D.)
- Instituto de Investigaciones Biológicas Clemente Estable (IIBCE), Montevideo 11600, Uruguay
| | - Rosario Durán
- Unidad de Bioquímica y Proteómica Analítica, Institut Pasteur de Montevideo, Montevideo 11400, Uruguay; (M.P.); (R.D.)
- Instituto de Investigaciones Biológicas Clemente Estable (IIBCE), Montevideo 11600, Uruguay
| | - Mario Pablo Estrada
- Animal Biotechnology Department, Center for Genetic Engineering and Biotechnology (CIGB), Havana 10600, Cuba; (P.E.E.G.); (Y.B.S.); (M.P.E.)
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7
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Comprehensive analysis of posttranslational protein modifications in aging of subcellular compartments. Sci Rep 2020; 10:7596. [PMID: 32371922 PMCID: PMC7200742 DOI: 10.1038/s41598-020-64265-0] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2019] [Accepted: 03/27/2020] [Indexed: 12/16/2022] Open
Abstract
Enzymatic and non-enzymatic posttranslational protein modifications by oxidation, glycation and acylation are key regulatory mechanisms in hallmarks of aging like inflammation, altered epigenetics and decline in proteostasis. In this study a mouse cohort was used to monitor changes of posttranslational modifications in the aging process. A protocol for the extraction of histones, cytosolic and mitochondrial proteins from mouse liver was developed and validated. In total, 6 lysine acylation structures, 7 advanced glycation endproducts, 6 oxidative stress markers, and citrullination were quantitated in proteins of subcellular compartments using HPLC-MS/MS. Methionine sulfoxide, acetylation, formylation, and citrullination were the most abundant modifications. Histone proteins were extraordinary high modified and non-enzymatic modifications accumulated in all subcellular compartments during the aging process. Compared to acetylation of histone proteins which gave between 350 and 305 µmol/mol leucine equivalents in young and old animals, modifications like acylation, glycation, and citrullination raised to 43%, 20%, and 18% of acetylation, respectively. On the other hand there was an age related increase of selected oxidative stress markers by up to 150%. The data and patterns measured in this study are mandatory for further studies and will strongly facilitate understanding of the molecular mechanisms in aging.
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8
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Formaldehyde Exposure and Epigenetic Effects: A Systematic Review. APPLIED SCIENCES-BASEL 2020. [DOI: 10.3390/app10072319] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Formaldehyde (FA) is a general living and occupational pollutant, classified as carcinogenic for humans. Although genotoxicity is recognized as a FA mechanism of action, a potential contribution of epigenetic effects cannot be excluded. Therefore, aim of this review is to comprehensively assess possible epigenetic alterations induced by FA exposure in humans, animals, and cellular models. A systematic review of Pubmed, Scopus, and Isi Web of Science databases was performed. DNA global methylation changes were demonstrated in workers exposed to FA, and also in human bronchial cells. Histone alterations, i.e., the reduction in acetylation of histone lysine residues, in human lung cells were induced by FA. Moreover, a dysregulation of microRNA expression in human lung adenocarcinoma cells as well as in the nose, olfactory bulb and white blood cells of rodents and nonhuman primates was reported. Although preliminary, these findings suggest the role of epigenetic modifications as possible FA mechanisms of action that need deeper qualitative and quantitative investigation. This may allow to define the role of such alterations as indicators of early biological effect and the opportunity to include such information in future risk assessment and management strategies for public and occupationally FA-exposed populations.
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9
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Zhao Y, Chan CK, Chan KKJ, Chan W. Quantitation of N6-Formyl-lysine Adduct Following Aristolochic Acid Exposure in Cells and Rat Tissues by Liquid Chromatography-Tandem Mass Spectrometry Coupled with Stable Isotope-Dilution Method. Chem Res Toxicol 2019; 32:2086-2094. [DOI: 10.1021/acs.chemrestox.9b00272] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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10
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Andersen ME, Gentry PR, Swenberg JA, Mundt KA, White KW, Thompson C, Bus J, Sherman JH, Greim H, Bolt H, Marsh GM, Checkoway H, Coggon D, Clewell HJ. Considerations for refining the risk assessment process for formaldehyde: Results from an interdisciplinary workshop. Regul Toxicol Pharmacol 2019; 106:210-223. [PMID: 31059732 DOI: 10.1016/j.yrtph.2019.04.015] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2018] [Revised: 04/17/2019] [Accepted: 04/21/2019] [Indexed: 01/06/2023]
Abstract
Anticipating the need to evaluate and integrate scientific evidence to inform new risk assessments or to update existing risk assessments, the Formaldehyde Panel of the American Chemistry Council (ACC), in collaboration with the University of North Carolina, convened a workshop: "Understanding Potential Human Health Cancer Risk - From Data Integration to Risk Evaluation" in October 2017. Twenty-four (24) invited-experts participated with expertise in epidemiology, toxicology, science integration and risk evaluation. Including members of the organizing committee, there were 29 participants. The meeting included eleven presentations encompassing an introduction and three sessions: (1) "integrating the formaldehyde science on nasal/nasopharyngeal carcinogenicity and potential for causality"; (2) "integrating the formaldehyde science on lymphohematopoietic cancer and potential for causality; and, (3) "formaldehyde research-data suitable for risk assessment". Here we describe key points from the presentations on epidemiology, toxicology and mechanistic studies that should inform decisions about the potential carcinogenicity of formaldehyde in humans and the discussions about approaches for structuring an integrated, comprehensive risk assessment for formaldehyde. We also note challenges expected when attempting to reconcile divergent results observed from research conducted within and across different scientific disciplines - especially toxicology and epidemiology - and in integrating diverse, multi-disciplinary mechanistic evidence.
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Affiliation(s)
- Melvin E Andersen
- ScitoVation LLC, 100 Capitola Drive, Drive 106, Durham, NC, 27713, USA.
| | | | - James A Swenberg
- Department of Environmental Sciences and Engineering, Gillings School of Global Public Health, University of North Carolina, Chapel Hill, NC, USA
| | - Kenneth A Mundt
- Ramboll US Corporation, Amherst, MA (currently with Cardno Chemrisk, Boston, MA, USA
| | | | | | - James Bus
- Center for Toxicology and Mechanistic Biology, Exponent, Alexandria, VA, USA
| | | | | | - Hermann Bolt
- Leibniz Institute for Working Environment and Human Factors (IfADo), Dortmund, Germany
| | - Gary M Marsh
- Department of Biostatistics, Center for Occupational Biostatistics and Epidemiology, Graduate School of Public Health, University of Pittsburgh, Pittsburgh, PA, USA
| | - Harvey Checkoway
- University of California, San Diego, Department of Family Medicine and Public Health, USA
| | - David Coggon
- MRC Lifecourse Epidemiology Unit, University of Southampton, United Kingdom
| | - Harvey J Clewell
- Ramboll US Corporation, 6 Davis Drive, Suite 13, Research Triangle Park, NC, 27709, USA
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11
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Chan W, Ham YH, Jin L, Chan HW, Wong YL, Chan CK, Chung PY. Quantification of a Novel DNA–Protein Cross-Link Product Formed by Reacting Apurinic/Apyrimidinic Sites in DNA with Cysteine Residues in Protein by Liquid Chromatography-Tandem Mass Spectrometry Coupled with the Stable Isotope-Dilution Method. Anal Chem 2019; 91:4987-4994. [DOI: 10.1021/acs.analchem.8b04306] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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12
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Evaluation of inhaled low-dose formaldehyde-induced DNA adducts and DNA-protein cross-links by liquid chromatography-tandem mass spectrometry. Arch Toxicol 2019; 93:763-773. [PMID: 30701286 DOI: 10.1007/s00204-019-02393-x] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2018] [Accepted: 01/10/2019] [Indexed: 12/11/2022]
Abstract
As a widespread industrial chemical, formaldehyde carcinogenicity has been highly controversial. Meanwhile, formaldehyde is an essential metabolite in all living cells. Previously, we have demonstrated exogenous formaldehyde causes DNA adducts in a nonlinear manner between 0.7 and 15.2 ppm using [13CD2]-formaldehyde for exposure coupled with the use of sensitive mass spectrometry. However, the responses from exposure to low doses of formaldehyde are still unknown. In this study, rats were exposed to 1, 30, and 300 ppb [13CD2]-formaldehyde for 28 days (6 h/day) by nose-only inhalation, followed by measuring DNA mono-adduct (N2-HOMe-dG) and DNA-protein crosslinks (dG-Me-Cys) as formaldehyde specific biomarkers. Both exogenous and endogenous DNA mono-adducts and dG-Me-Cys were examined with ultrasensitive nano-liquid chromatography-tandem mass spectrometry. Our data clearly show that endogenous adducts are present in all tissues analyzed, but exogenous adducts were not detectable in any tissue samples, including the most susceptible nasal epithelium. Moreover, formaldehyde exposure at 1, 30 and 300 ppb did not alter the levels of endogenous formaldehyde-induced DNA adducts or DNA-protein crosslinks. The novel findings from this study provide new data for risk assessment of exposure to low doses of formaldehyde.
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13
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Wolkoff P, Nielsen GD. Comment on "Differential Health Effects of Constant and Intermittent Exposure to Formaldehyde in Mice: Implications for Building Ventilation Strategies". ENVIRONMENTAL SCIENCE & TECHNOLOGY 2018; 52:3320-3321. [PMID: 29465991 DOI: 10.1021/acs.est.8b00313] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
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14
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Mundt KA, Gentry PR, Dell LD, Rodricks JV, Boffetta P. Six years after the NRC review of EPA's Draft IRIS Toxicological Review of Formaldehyde: Regulatory implications of new science in evaluating formaldehyde leukemogenicity. Regul Toxicol Pharmacol 2017; 92:472-490. [PMID: 29158043 DOI: 10.1016/j.yrtph.2017.11.006] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2017] [Revised: 10/27/2017] [Accepted: 11/15/2017] [Indexed: 11/28/2022]
Abstract
Shortly after the International Agency for Research on Cancer (IARC) determined that formaldehyde causes leukemia, the United States Environmental Protection Agency (EPA) released its Draft IRIS Toxicological Review of Formaldehyde ("Draft IRIS Assessment"), also concluding that formaldehyde causes leukemia. Peer review of the Draft IRIS Assessment by a National Academy of Science committee noted that "causal determinations are not supported by the narrative provided in the draft" (NRC 2011). They offered recommendations for improving the Draft IRIS assessment and identified several important research gaps. Over the six years since the NRC peer review, significant new science has been published. We identify and summarize key recommendations made by NRC and map them to this new science, including extended analysis of epidemiological studies, updates of earlier occupational cohort studies, toxicological experiments using a sensitive mouse strain, mechanistic studies examining the role of exogenous versus endogenous formaldehyde in bone marrow, and several critical reviews. With few exceptions, new findings are consistently negative, and integration of all available evidence challenges the earlier conclusions that formaldehyde causes leukemia. Given formaldehyde's commercial importance, environmental ubiquity and endogenous production, accurate hazard classification and risk evaluation of whether exposure to formaldehyde from occupational, residential and consumer products causes leukemia are critical.
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Affiliation(s)
- Kenneth A Mundt
- Environment and Health, Ramboll Environ, Amherst MA, United States.
| | - P Robinan Gentry
- Environment and Health, Ramboll Environ, Amherst MA, United States
| | - Linda D Dell
- Environment and Health, Ramboll Environ, Amherst MA, United States
| | | | - Paolo Boffetta
- Icahn School of Medicine at Mount Sinai, New York, NY, USA
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15
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Chen D, Fang L, Mei S, Li H, Xu X, Des Marais TL, Lu K, Liu XS, Jin C. Regulation of Chromatin Assembly and Cell Transformation by Formaldehyde Exposure in Human Cells. ENVIRONMENTAL HEALTH PERSPECTIVES 2017; 125:097019. [PMID: 28937961 PMCID: PMC5915180 DOI: 10.1289/ehp1275] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/25/2016] [Revised: 05/19/2017] [Accepted: 05/23/2017] [Indexed: 06/07/2023]
Abstract
BACKGROUND Formaldehyde (FA) is an environmental and occupational chemical carcinogen. Recent studies have shown that exogenous FA causes only a modest increase in DNA adduct formation compared with the amount of adducts formed by endogenous FA, raising the possibility that epigenetic mechanisms may contribute to FA-mediated carcinogenicity. OBJECTIVES We investigated the effects of FA exposure on histone modifications and chromatin assembly. We also examined the role of defective chromatin assembly in FA-mediated transcription and cell transformation. METHODS Cellular fractionation and Western blot analysis were used to measure the levels of histone modifications in human bronchial epithelial BEAS-2B cells and human nasal RPMI2650 cells in the presence of FA. Chromatin immunoprecipitation (ChIP) and micrococcal nuclease (MNase) digest assays were performed to examine the changes in chromatin assembly and accessibility after FA exposure. RNA sequencing (RNA-seq) and real-time polymerase chain reaction (PCR) were used to examine transcriptional dysregulation. Finally, anchorage-independent cell growth ability was tested by soft agar assay following FA exposure. RESULTS Exposure to FA dramatically decreased the acetylation of the N-terminal tails of cytosolic histones. These modifications are important for histone nuclear import and subsequent chromatin assembly. Histone proteins were depleted in both the chromatin fraction and at most of the genomic loci tested following FA exposure, suggesting that FA compromises chromatin assembly. Moreover, FA increased chromatin accessibility and altered the expression of hundreds of cancer-related genes. Knockdown of the histone H3.3 gene (an H3 variant), which mimics inhibition of chromatin assembly, facilitated FA-mediated anchorage-independent cell growth. CONCLUSIONS We propose that the inhibition of chromatin assembly represents a novel mechanism of cell transformation induced by the environmental and occupational chemical carcinogen FA. https://doi.org/10.1289/EHP1275.
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Affiliation(s)
- Danqi Chen
- Department of Environmental Medicine and Biochemistry and Molecular Pharmacology, New York University School of Medicine, New York, New York, USA
| | - Lei Fang
- Department of Environmental Medicine and Biochemistry and Molecular Pharmacology, New York University School of Medicine, New York, New York, USA
| | - Shenglin Mei
- Department of Bioinformatics, School of Life Sciences, Tongji University, Shanghai, China
| | - Hongjie Li
- Department of Environmental Medicine and Biochemistry and Molecular Pharmacology, New York University School of Medicine, New York, New York, USA
| | - Xia Xu
- Department of Environmental Medicine and Biochemistry and Molecular Pharmacology, New York University School of Medicine, New York, New York, USA
| | - Thomas L Des Marais
- Department of Environmental Medicine and Biochemistry and Molecular Pharmacology, New York University School of Medicine, New York, New York, USA
| | - Kun Lu
- Department of Environmental Sciences and Engineering, University of North Carolina, Chapel Hill, North Carolina, USA
| | - X Shirley Liu
- Department of Biostatistics and Computational Biology, Dana-Farber Cancer Institute and Harvard T.H. Chan School of Public Health, Boston, Massachusetts, USA
| | - Chunyuan Jin
- Department of Environmental Medicine and Biochemistry and Molecular Pharmacology, New York University School of Medicine, New York, New York, USA
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16
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Edrissi B, Taghizadeh K, Moeller BC, Yu R, Kracko D, Doyle-Eisele M, Swenberg JA, Dedon PC. N 6-Formyllysine as a Biomarker of Formaldehyde Exposure: Formation and Loss of N 6-Formyllysine in Nasal Epithelium in Long-Term, Low-Dose Inhalation Studies in Rats. Chem Res Toxicol 2017; 30:1572-1576. [PMID: 28692800 PMCID: PMC5807069 DOI: 10.1021/acs.chemrestox.7b00075] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Exposure to both endogenous and exogenous formaldehyde has been established to be carcinogenic, likely by virtue of forming nucleic acid and proteins adducts such as N6-formyllysine. To better assess N6-formyllysine as a biomarker of formaldehyde exposure, we studied accumulation of N6-formyllysine adducts in tissues of rats exposed by inhalation to 2 ppm [13C2H2]-formaldehyde for 7, 14, 21, and 28 days (6 h/day) and investigated adduct loss over a 7-day postexposure period using liquid chromatography-coupled tandem mass spectrometry. Our results showed formation of exogenous adducts in nasal epithelium and to some extent in trachea but not in distant tissues of lung, bone marrow, or white blood cells, with a 2-fold increase over endogenous N6-formyllysine over a 3-week exposure period. Postexposure analyses indicated a biexponential decay of N6-formyllysine in proteins extracted from different cellular compartments, with half-lives of ∼25 and ∼182 h for the fast and slow phases, respectively, in cytoplasmic proteins. These results parallel the behavior of DNA adducts and DNA-protein cross-links, with protein adducts cleared faster than DNA-protein cross-links, and point to the potential utility of N6-formyllysine protein adducts as biomarkers of formaldehyde.
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Affiliation(s)
- Bahar Edrissi
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
| | - Koli Taghizadeh
- Center for Environmental Health Sciences, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
| | - Benjamin C. Moeller
- Department of Environmental Sciences and Engineering, University of North Carolina, Chapel Hill, NC, 27514, USA
- Lovelace Respiratory Research Institute, Albuquerque, NM, 87108, USA
| | - Rui Yu
- Department of Environmental Sciences and Engineering, University of North Carolina, Chapel Hill, NC, 27514, USA
| | - Dean Kracko
- Lovelace Respiratory Research Institute, Albuquerque, NM, 87108, USA
| | | | - James A. Swenberg
- Department of Environmental Sciences and Engineering, University of North Carolina, Chapel Hill, NC, 27514, USA
| | - Peter C. Dedon
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
- Center for Environmental Health Sciences, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
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17
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Regazzoni LG, Grigoryan H, Ji Z, Chen X, Daniels SI, Huang D, Sanchez S, Tang N, Sillé FCM, Iavarone AT, Williams ER, Zhang L, Rappaport SM. Using lysine adducts of human serum albumin to investigate the disposition of exogenous formaldehyde in human blood. Toxicol Lett 2017; 268:26-35. [PMID: 28104429 DOI: 10.1016/j.toxlet.2017.01.002] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2016] [Revised: 12/19/2016] [Accepted: 01/04/2017] [Indexed: 12/20/2022]
Abstract
Formaldehyde is a human carcinogen that readily binds to nucleophiles, including proteins and DNA. To investigate whether exogenous formaldehyde produces adducts in extracellular fluids, we characterized modifications to human serum albumin (HSA) following incubation of whole blood, plasma, and saliva with formaldehyde at concentrations of 1, 10 and 100μM. The only HSA locus that showed the presence of formaldehyde modifications was Lys199. A N(6)-Lys adduct with added mass of 12Da, representing a putative intramolecular crosslink, was detected in biological fluids that had been incubated with formaldehyde but not in control fluids. An adduct representing N(6)-Lys formylation was detected in all fluids, but levels did not increase above control values over the tested range of formaldehyde concentrations. An adduct representing N(6)-Lys199 acetylation was also measured in all samples. We then applied the assay to repeated samples of human plasma from 6 nonsmoking volunteer subjects (from Berkeley, CA), and single samples of serum from 15 workers exposed to airborne formaldehyde at about 1.5ppm in a production facility and 15 control workers from Tianjin, China. Although all human plasma/serum samples contained basal levels of the products of N(6)-Lys formylation and acetylation, the putative crosslink product was not detected. Since the putative crosslink was observed in plasma incubated with formaldehyde at 1μM, this suggests that the endogenous concentration of formaldehyde in serum was much lower than reported in the literature. Furthermore, concentrations of the formyl adduct were not higher in workers exposed to formaldehyde at about 1.5ppm than in controls. Follow-up in vitro experiments with gaseous formaldehyde at 1.4ppm detected the putative crosslink in plasma but not whole blood. This combination of results suggests that N(6) formylation occurs within cells with subsequent release of adducted HSA to the systemic circulation. Comparing across human samples, levels of N(6)-Lys199 formyl adducts were present at similar concentrations in subjects from California and China (about 1mmol/mol HSA), but N(6)-Lys199 acetyl adducts were present at higher concentrations in Chinese subjects (0.34 vs. 0.13mmol/mol HSA).
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Affiliation(s)
- Luca G Regazzoni
- Division of Environmental Health Sciences, School of Public Health, University of California, Berkeley, CA, United States
| | - Hasmik Grigoryan
- Division of Environmental Health Sciences, School of Public Health, University of California, Berkeley, CA, United States
| | - Zhiying Ji
- Division of Environmental Health Sciences, School of Public Health, University of California, Berkeley, CA, United States
| | - Xi Chen
- Department of Occupational and Environmental Health, School of Public Health, Tianjin Medical University, Tianjin, China
| | - Sarah I Daniels
- Division of Environmental Health Sciences, School of Public Health, University of California, Berkeley, CA, United States
| | - Deyin Huang
- Institute of Occupational Health, School of Public Health, Tianjin Bohai Chemical Industry Group Co. Ltd., Tianjin, China
| | - Sylvia Sanchez
- Division of Environmental Health Sciences, School of Public Health, University of California, Berkeley, CA, United States
| | - Naijun Tang
- Department of Occupational and Environmental Health, School of Public Health, Tianjin Medical University, Tianjin, China
| | - Fenna C M Sillé
- Division of Environmental Health Sciences, School of Public Health, University of California, Berkeley, CA, United States
| | - Anthony T Iavarone
- California Institute for Quantitative Biosciences and Department of Chemistry, University of California, Berkeley, CA, United States
| | - Evan R Williams
- California Institute for Quantitative Biosciences and Department of Chemistry, University of California, Berkeley, CA, United States
| | - Luoping Zhang
- Division of Environmental Health Sciences, School of Public Health, University of California, Berkeley, CA, United States
| | - Stephen M Rappaport
- Division of Environmental Health Sciences, School of Public Health, University of California, Berkeley, CA, United States.
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18
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Nielsen GD, Larsen ST, Wolkoff P. Re-evaluation of the WHO (2010) formaldehyde indoor air quality guideline for cancer risk assessment. Arch Toxicol 2017; 91:35-61. [PMID: 27209488 PMCID: PMC5225186 DOI: 10.1007/s00204-016-1733-8] [Citation(s) in RCA: 112] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2016] [Accepted: 04/27/2016] [Indexed: 11/11/2022]
Abstract
In 2010, the World Health Organization (WHO) established an indoor air quality guideline for short- and long-term exposures to formaldehyde (FA) of 0.1 mg/m3 (0.08 ppm) for all 30-min periods at lifelong exposure. This guideline was supported by studies from 2010 to 2013. Since 2013, new key studies have been published and key cancer cohorts have been updated, which we have evaluated and compared with the WHO guideline. FA is genotoxic, causing DNA adduct formation, and has a clastogenic effect; exposure-response relationships were nonlinear. Relevant genetic polymorphisms were not identified. Normal indoor air FA concentrations do not pass beyond the respiratory epithelium, and therefore FA's direct effects are limited to portal-of-entry effects. However, systemic effects have been observed in rats and mice, which may be due to secondary effects as airway inflammation and (sensory) irritation of eyes and the upper airways, which inter alia decreases respiratory ventilation. Both secondary effects are prevented at the guideline level. Nasopharyngeal cancer and leukaemia were observed inconsistently among studies; new updates of the US National Cancer Institute (NCI) cohort confirmed that the relative risk was not increased with mean FA exposures below 1 ppm and peak exposures below 4 ppm. Hodgkin's lymphoma, not observed in the other studies reviewed and not considered FA dependent, was increased in the NCI cohort at a mean concentration ≥0.6 mg/m3 and at peak exposures ≥2.5 mg/m3; both levels are above the WHO guideline. Overall, the credibility of the WHO guideline has not been challenged by new studies.
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Affiliation(s)
- Gunnar Damgård Nielsen
- National Research Centre for the Working Environment, Lersø Parkallé 105, 2100, Copenhagen, Denmark.
| | - Søren Thor Larsen
- National Research Centre for the Working Environment, Lersø Parkallé 105, 2100, Copenhagen, Denmark
| | - Peder Wolkoff
- National Research Centre for the Working Environment, Lersø Parkallé 105, 2100, Copenhagen, Denmark
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19
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Chiarella P, Tranfo G, Pigini D, Carbonari D. Is it possible to use biomonitoring for the quantitative assessment of formaldehyde occupational exposure? Biomark Med 2016; 10:1287-1303. [PMID: 27924628 DOI: 10.2217/bmm-2016-0146] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
The European classification, labeling and packaging classified formaldehyde as human carcinogen Group 1B and mutagen 2, fostering the re-evaluation of the exposure risk in occupational settings. Although formaldehyde exposure is traditionally measured in air, many efforts were made to identify specific exposure biomarkers: urinary formaldehyde, formic acid and DNA damage indicators. Though used in combination, none of these seems satisfactory. The influence of the metabolism on exogenous formaldehyde levels, the exposure to other xenobiotics, the difference in genetic background and metabolism efficiency, misled the relationship between genotoxicity and exposure data. Nevertheless, the limitation of adverse effects to the local contact sites hampers biomonitoring. Here we discuss the feasibility of formaldehyde biomonitoring and the use of DNA, DNA-protein cross-links and protein adducts as potential biomarkers.
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Affiliation(s)
- Pieranna Chiarella
- INAIL Research - Department of Occupational & Environmental Medicine, Epidemiology & Hygiene, Via Fontana Candida 1 - 00078 Monte Porzio Catone (RM), Italy
| | - Giovanna Tranfo
- INAIL Research - Department of Occupational & Environmental Medicine, Epidemiology & Hygiene, Via Fontana Candida 1 - 00078 Monte Porzio Catone (RM), Italy
| | - Daniela Pigini
- INAIL Research - Department of Occupational & Environmental Medicine, Epidemiology & Hygiene, Via Fontana Candida 1 - 00078 Monte Porzio Catone (RM), Italy
| | - Damiano Carbonari
- INAIL Research - Department of Occupational & Environmental Medicine, Epidemiology & Hygiene, Via Fontana Candida 1 - 00078 Monte Porzio Catone (RM), Italy
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20
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Liu J, Chan KKJ, Chan W. Identification of Protein Thiazolidination as a Novel Molecular Signature for Oxidative Stress and Formaldehyde Exposure. Chem Res Toxicol 2016; 29:1865-1871. [DOI: 10.1021/acs.chemrestox.6b00271] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Affiliation(s)
- Jingjing Liu
- Environmental Science Programs and ‡Department of
Chemistry, The Hong Kong University of Science and Technology, Clear
Water Bay, Kowloon, Hong Kong
| | - K. K. Jason Chan
- Environmental Science Programs and ‡Department of
Chemistry, The Hong Kong University of Science and Technology, Clear
Water Bay, Kowloon, Hong Kong
| | - Wan Chan
- Environmental Science Programs and ‡Department of
Chemistry, The Hong Kong University of Science and Technology, Clear
Water Bay, Kowloon, Hong Kong
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21
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Van Landingham C, Mundt KA, Allen BC, Gentry PR. The need for transparency and reproducibility in documenting values for regulatory decision making and evaluating causality: The example of formaldehyde. Regul Toxicol Pharmacol 2016; 81:512-521. [DOI: 10.1016/j.yrtph.2016.10.011] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2016] [Revised: 10/17/2016] [Accepted: 10/18/2016] [Indexed: 12/22/2022]
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22
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Albertini RJ, Kaden DA. Do chromosome changes in blood cells implicate formaldehyde as a leukemogen? Crit Rev Toxicol 2016; 47:145-184. [DOI: 10.1080/10408444.2016.1211987] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
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23
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Wei C, Wen H, Yuan L, McHale CM, Li H, Wang K, Yuan J, Yang X, Zhang L. Formaldehyde induces toxicity in mouse bone marrow and hematopoietic stem/progenitor cells and enhances benzene-induced adverse effects. Arch Toxicol 2016; 91:921-933. [PMID: 27339418 DOI: 10.1007/s00204-016-1760-5] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2015] [Accepted: 06/13/2016] [Indexed: 12/13/2022]
Abstract
FA in air for 2 weeks, mimicking occupational exposure, then measured complete blood counts, nucleated BM cell count, and myeloid progenitor colony formation. We also investigated potential mechanisms of FA toxicity, including reactive oxygen species (ROS) generation, apoptosis, and hematopoietic growth factor and receptor levels. FA exposure significantly reduced nucleated BM cells and BM-derived colony-forming unit-granulocyte-macrophage (CFU-GM) and burst-forming unit-erythroid (BFU-E); down-regulated GM-CSFRα and EPOR expression; increased ROS in nucleated BM, spleen and CFU-GM cells; and increased apoptosis in nucleated spleen and CFU-GM cells. FA and BZ each similarly altered BM mature cells and stem/progenitor counts, BM and CFU-GM ROS, and apoptosis in spleen and CFU-GM but had differential effects on other end points. Co-exposure was more potent for several end points. Thus, FA is toxic to the mouse hematopoietic system, including BM stem/progenitor cells, and it enhances BZ-induced toxic effects. Our findings suggest that FA may induce BM toxicity by affecting myeloid progenitor growth and survival through oxidative damage and reduced expression levels of GM-CSFRα and EPOR.
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Affiliation(s)
- Chenxi Wei
- Hubei Key Laboratory of Genetic Regulation and Integrative Biology, College of Life Sciences, Central China Normal University, Wuhan, 430079, Hubei, China.,Key Laboratory of Ecological Safety Monitoring and Evaluation, College of Life Sciences, Hunan Normal University, Changsha, 410081, Hunan, China
| | - Huaxiao Wen
- Hubei Key Laboratory of Genetic Regulation and Integrative Biology, College of Life Sciences, Central China Normal University, Wuhan, 430079, Hubei, China
| | - Langyue Yuan
- Hubei Key Laboratory of Genetic Regulation and Integrative Biology, College of Life Sciences, Central China Normal University, Wuhan, 430079, Hubei, China
| | - Cliona M McHale
- Division of Environmental Health Sciences, School of Public Health, University of California, Berkeley, CA, 94720, USA
| | - Hui Li
- Hubei Key Laboratory of Genetic Regulation and Integrative Biology, College of Life Sciences, Central China Normal University, Wuhan, 430079, Hubei, China
| | - Kun Wang
- Hubei Key Laboratory of Genetic Regulation and Integrative Biology, College of Life Sciences, Central China Normal University, Wuhan, 430079, Hubei, China.,Division of Biostatistics, Department of Population Health, School of Medicine, New York University, New York, NY, USA
| | - Junlin Yuan
- Hubei Key Laboratory of Genetic Regulation and Integrative Biology, College of Life Sciences, Central China Normal University, Wuhan, 430079, Hubei, China
| | - Xu Yang
- Hubei Key Laboratory of Genetic Regulation and Integrative Biology, College of Life Sciences, Central China Normal University, Wuhan, 430079, Hubei, China.
| | - Luoping Zhang
- Division of Environmental Health Sciences, School of Public Health, University of California, Berkeley, CA, 94720, USA.
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24
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Lai Y, Yu R, Hartwell HJ, Moeller BC, Bodnar WM, Swenberg JA. Measurement of Endogenous versus Exogenous Formaldehyde-Induced DNA-Protein Crosslinks in Animal Tissues by Stable Isotope Labeling and Ultrasensitive Mass Spectrometry. Cancer Res 2016; 76:2652-61. [PMID: 26984759 DOI: 10.1158/0008-5472.can-15-2527] [Citation(s) in RCA: 59] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2015] [Accepted: 02/14/2016] [Indexed: 12/24/2022]
Abstract
DNA-protein crosslinks (DPC) arise from a wide range of endogenous and exogenous chemicals, such as chemotherapeutic drugs and formaldehyde. Importantly, recent identification of aldehydes as endogenous genotoxins in Fanconi anemia has provided new insight into disease causation. Because of their bulky nature, DPCs pose severe threats to genome stability, but previous methods to measure formaldehyde-induced DPCs were incapable of discriminating between endogenous and exogenous sources of chemical. In this study, we developed methods that provide accurate and distinct measurements of both exogenous and endogenous DPCs in a structurally specific manner. We exposed experimental animals to stable isotope-labeled formaldehyde ([(13)CD2]-formaldehyde) by inhalation and performed ultrasensitive mass spectrometry to measure endogenous (unlabeled) and exogenous ((13)CD2-labeled) DPCs. We found that exogenous DPCs readily accumulated in nasal respiratory tissues but were absent in tissues distant to the site of contact. This observation, together with the finding that endogenous formaldehyde-induced DPCs were present in all tissues examined, suggests that endogenous DPCs may be responsible for increased risks of bone marrow toxicity and leukemia. Furthermore, the slow rate of DPC repair provided evidence for the persistence of DPCs. In conclusion, our method for measuring endogenous and exogenous DPCs presents a new perspective for the potential health risks inflicted by endogenous formaldehyde and may inform improved disease prevention and treatment strategies. Cancer Res; 76(9); 2652-61. ©2016 AACR.
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Affiliation(s)
- Yongquan Lai
- Department of Environmental Sciences and Engineering, Gillings School of Global Public Health, the University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
| | - Rui Yu
- Department of Environmental Sciences and Engineering, Gillings School of Global Public Health, the University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
| | - Hadley J Hartwell
- Department of Environmental Sciences and Engineering, Gillings School of Global Public Health, the University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
| | | | - Wanda M Bodnar
- Department of Environmental Sciences and Engineering, Gillings School of Global Public Health, the University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
| | - James A Swenberg
- Department of Environmental Sciences and Engineering, Gillings School of Global Public Health, the University of North Carolina at Chapel Hill, Chapel Hill, North Carolina.
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25
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Yu R, Lai Y, Hartwell HJ, Moeller BC, Doyle-Eisele M, Kracko D, Bodnar WM, Starr TB, Swenberg JA. Formation, Accumulation, and Hydrolysis of Endogenous and Exogenous Formaldehyde-Induced DNA Damage. Toxicol Sci 2015; 146:170-82. [PMID: 25904104 PMCID: PMC4476463 DOI: 10.1093/toxsci/kfv079] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Formaldehyde is not only a widely used chemical with well-known carcinogenicity but is also a normal metabolite of living cells. It thus poses unique challenges for understanding risks associated with exposure. N(2-)hydroxymethyl-dG (N(2)-HOMe-dG) is the main formaldehyde-induced DNA mono-adduct, which together with DNA-protein crosslinks (DPCs) and toxicity-induced cell proliferation, play important roles in a mutagenic mode of action for cancer. In this study, N(2)-HOMe-dG was shown to be an excellent biomarker for direct adduction of formaldehyde to DNA and the hydrolysis of DPCs. The use of inhaled [(13)CD2]-formaldehyde exposures of rats and primates coupled with ultrasensitive nano ultra performance liquid chromatography-tandem mass spectrometry permitted accurate determinations of endogenous and exogenous formaldehyde DNA damage. The results show that inhaled formaldehyde only reached rat and monkey noses, but not tissues distant to the site of initial contact. The amounts of exogenous adducts were remarkably lower than those of endogenous adducts in exposed nasal epithelium. Moreover, exogenous adducts accumulated in rat nasal epithelium over the 28-days exposure to reach steady-state concentrations, followed by elimination with a half-life (t1/2) of 7.1 days. Additionally, we examined artifact formation during DNA preparation to ensure the accuracy of nonlabeled N(2)-HOMe-dG measurements. These novel findings provide critical new data for understanding major issues identified by the National Research Council Review of the 2010 Environmental Protection Agency's Draft Integrated Risk Information System Formaldehyde Risk Assessment. They support a data-driven need for reflection on whether risks have been overestimated for inhaled formaldehyde, whereas underappreciating endogenous formaldehyde as the primary source of exposure that results in bone marrow toxicity and leukemia in susceptible humans and rodents deficient in DNA repair.
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Affiliation(s)
- Rui Yu
- *Department of Environmental Sciences and Engineering, Gillings School of Global Public Health, The University of North Carolina, Chapel Hill, North Carolina 27599
| | - Yongquan Lai
- *Department of Environmental Sciences and Engineering, Gillings School of Global Public Health, The University of North Carolina, Chapel Hill, North Carolina 27599
| | - Hadley J Hartwell
- *Department of Environmental Sciences and Engineering, Gillings School of Global Public Health, The University of North Carolina, Chapel Hill, North Carolina 27599
| | - Benjamin C Moeller
- Lovelace Respiratory Research Institute, Albuquerque, New Mexico 87108; and
| | | | - Dean Kracko
- Lovelace Respiratory Research Institute, Albuquerque, New Mexico 87108; and
| | - Wanda M Bodnar
- *Department of Environmental Sciences and Engineering, Gillings School of Global Public Health, The University of North Carolina, Chapel Hill, North Carolina 27599
| | - Thomas B Starr
- *Department of Environmental Sciences and Engineering, Gillings School of Global Public Health, The University of North Carolina, Chapel Hill, North Carolina 27599, TBS Associates, 7500 Rainwater Road, Raleigh, North Carolina 27615
| | - James A Swenberg
- *Department of Environmental Sciences and Engineering, Gillings School of Global Public Health, The University of North Carolina, Chapel Hill, North Carolina 27599,
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26
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Nakamura J, Mutlu E, Sharma V, Collins L, Bodnar W, Yu R, Lai Y, Moeller B, Lu K, Swenberg J. The endogenous exposome. DNA Repair (Amst) 2014; 19:3-13. [PMID: 24767943 PMCID: PMC4097170 DOI: 10.1016/j.dnarep.2014.03.031] [Citation(s) in RCA: 66] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The concept of the Exposome is a compilation of diseases and one's lifetime exposure to chemicals, whether the exposure comes from environmental, dietary, or occupational exposures; or endogenous chemicals that are formed from normal metabolism, inflammation, oxidative stress, lipid peroxidation, infections, and other natural metabolic processes such as alteration of the gut microbiome. In this review, we have focused on the endogenous exposome, the DNA damage that arises from the production of endogenous electrophilic molecules in our cells. It provides quantitative data on endogenous DNA damage and its relationship to mutagenesis, with emphasis on when exogenous chemical exposures that produce identical DNA adducts to those arising from normal metabolism cause significant increases in total identical DNA adducts. We have utilized stable isotope labeled chemical exposures of animals and cells, so that accurate relationships between endogenous and exogenous exposures can be determined. Advances in mass spectrometry have vastly increased both the sensitivity and accuracy of such studies. Furthermore, we have clear evidence of which sources of exposure drive low dose biology that results in mutations and disease. These data provide much needed information to impact quantitative risk assessments, in the hope of moving towards the use of science, rather than default assumptions.
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Affiliation(s)
- Jun Nakamura
- University of North Carolina, Chapel Hill, NC, United States
| | - Esra Mutlu
- University of North Carolina, Chapel Hill, NC, United States
| | - Vyom Sharma
- University of North Carolina, Chapel Hill, NC, United States
| | - Leonard Collins
- University of North Carolina, Chapel Hill, NC, United States
| | - Wanda Bodnar
- University of North Carolina, Chapel Hill, NC, United States
| | - Rui Yu
- University of North Carolina, Chapel Hill, NC, United States
| | - Yongquan Lai
- University of North Carolina, Chapel Hill, NC, United States
| | - Benjamin Moeller
- University of North Carolina, Chapel Hill, NC, United States; Lovelace Respiratory Research Institute, Albuquerque, NM, United States
| | - Kun Lu
- University of North Carolina, Chapel Hill, NC, United States
| | - James Swenberg
- University of North Carolina, Chapel Hill, NC, United States.
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27
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Schroeter JD, Campbell J, Kimbell JS, Conolly RB, Clewell HJ, Andersen ME. Effects of endogenous formaldehyde in nasal tissues on inhaled formaldehyde dosimetry predictions in the rat, monkey, and human nasal passages. Toxicol Sci 2014; 138:412-24. [PMID: 24385418 DOI: 10.1093/toxsci/kft333] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Formaldehyde is a nasal carcinogen in rodents at high doses and is an endogenous compound that is present in all living cells. Due to its high solubility and reactivity, quantitative risk estimates for inhaled formaldehyde have relied on internal dose estimates in the upper respiratory tract. Dosimetry calculations are complicated by the presence of endogenous formaldehyde concentrations in the respiratory mucosa. Anatomically accurate computational fluid dynamics (CFD) models of the rat, monkey, and human nasal passages were used to simulate uptake of inhaled formaldehyde. An epithelial structure was implemented in the nasal CFD models to estimate formaldehyde absorption from air:tissue partitioning, species-specific metabolism, first-order clearance, DNA binding, and endogenous formaldehyde production. At an exposure concentration of 1 ppm, predicted formaldehyde nasal uptake was 99.4, 86.5, and 85.3% in the rat, monkey, and human, respectively. Endogenous formaldehyde in nasal tissues did not significantly affect wall mass flux or nasal uptake predictions at exposure concentrations > 500 ppb; however, reduced nasal uptake was predicted at lower exposure concentrations. At an exposure concentration of 1 ppb, predicted nasal uptake was 17.5 and 42.8% in the rat and monkey; net desorption of formaldehyde was predicted in the human model. The nonlinear behavior of formaldehyde nasal absorption will affect the dose-response analysis and subsequent risk estimates at low exposure concentrations. Updated surface area partitioning of nonsquamous epithelium and average flux values in regions where DNA-protein cross-links and cell proliferation rates were measured in rats and monkeys are reported for use in formaldehyde risk models of carcinogenesis.
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