1
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Ndreu L, Erber LN, Törnqvist M, Tretyakova NY, Karlsson I. Characterizing Adduct Formation of Electrophilic Skin Allergens with Human Serum Albumin and Hemoglobin. Chem Res Toxicol 2020; 33:2623-2636. [PMID: 32875789 PMCID: PMC7582624 DOI: 10.1021/acs.chemrestox.0c00271] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
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Skin
(contact) allergy, the most predominant form of immunotoxicity
in humans, is caused by small electrophilic compounds (haptens) that
modify endogenous proteins. Approximately 20% of the general population
in the Western world is affected by contact allergy. Although the
importance of the hapten–protein conjugates is well established
in the initiation of the immunological reaction, not much progress
has been made regarding identification of these conjugates in vivo or exploration of their potential as diagnostic
tools. In this study, the human serum albumin (HSA) and human hemoglobin
(Hb) adductome for three representative contact allergens with different
chemical properties, 1-chloro-2,4-dinitrobenzene (DNCB), 1,2-epoxy-3-phenoxypropane
(PGE), and 2-bromo-2-(bromomethyl)glutaronitrile (MDBGN), were studied.
Plasma and red blood cell lysate were used as a source for HSA and
Hb, respectively. The Direct Peptide Reactivity Assay was used to
investigate adduct formation of MDBGN with nucleophilic moieties and
revealed that MDGBN is converted to 2-methylenepentanedinitrile in
the presence of sulfhydryl groups prior to adduct formation. Following
incubation of HSA and Hb with haptens, an Orbitrap Q Exactive high-resolution
mass spectrometer was used to perform an initial untargeted analysis
to screen for adduct formation, followed by confirmation by targeted
Parallel Reaction Monitoring analysis. Although a subset of adducted
sites was confirmed by targeted analysis, only some of the adducted
peptides showed an increase in the relative amount of the adducted
peptide with an increased concentration of hapten. In total, seven
adduct sites for HSA and eight for Hb were confirmed for DNCB and
PGE. These sites are believed to be the most reactive. Further, three
of the HSA sites (Cys34, Cys62, and Lys190) and six of the Hb sites (subunit α: Val1, His45, His72; subunit β: Cys93, His97, and Cys112) were haptenated already
at the lowest level of hapten to protein molar ratio (0.1:1), indicating
that these sites are the most likely to be modified in vivo. To the best of our knowledge, this is the first time that the adductome
of Hb has been studied in the context of contact allergens. Identification
of the most reactive sites of abundant proteins, such as HSA and Hb,
is the first step toward identification of contact allergy biomarkers
that can be used for biomonitoring and to develop better diagnostic
tools based on a blood sample.
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Affiliation(s)
- Lorena Ndreu
- Department of Environmental Science, Stockholm University, SE-106 91 Stockholm, Sweden
| | - Luke N Erber
- Department of Medicinal Chemistry and the College of Pharmacy, University of Minnesota, Minneapolis, Minnesota 55455, United States.,Masonic Cancer Center, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - Margareta Törnqvist
- Department of Environmental Science, Stockholm University, SE-106 91 Stockholm, Sweden
| | - Natalia Y Tretyakova
- Department of Medicinal Chemistry and the College of Pharmacy, University of Minnesota, Minneapolis, Minnesota 55455, United States.,Masonic Cancer Center, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - Isabella Karlsson
- Department of Environmental Science, Stockholm University, SE-106 91 Stockholm, Sweden
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2
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Zhang Y, Li F, Peng N, Peng L. Environmental impact assessment of air-permeable plastic runway production in China. THE SCIENCE OF THE TOTAL ENVIRONMENT 2020; 730:139073. [PMID: 32388380 DOI: 10.1016/j.scitotenv.2020.139073] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/18/2020] [Revised: 04/25/2020] [Accepted: 04/26/2020] [Indexed: 06/11/2023]
Abstract
With the rapid development of plastic runways in China, incidents of toxic runways that are detrimental to human health frequently occurred. This phenomenon has resulted in public concern on the safety and cleanliness of plastic runways. To improve the sustainability of these runways, the environmental performance of the produced plastic runways should be evaluated. The critical hotspots for plastic runway studies should be determined, and a cleaner optimization path of critical materials should be explored. In this study, a cradle-to-gate life cycle assessment (LCA) on the air-permeable plastic runway was conducted. The green factory formula was identified, and the environmental impacts of the production process were quantitatively analyzed. Detailed life cycle inventory data were obtained from the on-site survey of typical plastic runway manufacturer enterprises in China. Environmental impacts were calculated using the CML 2001 method built into the GaBi 8.0 software. Results indicated that the 1: 7 ratio of polyurethane adhesive to ethylene-propylene-diene monomer rubber particles was the greenest formula with the least environmental impact. The environmental hotspots were from the front-end of raw material production during the mixing phase and the biomass steam input during the curing phase. The characteristic pollutants generated from mixing phase were CO2, methane, NOx, and VOCs, whereas those from the curing phase were CO2, NOx, SO2, freon, HCl, and NH3. Moreover, methylene diisocyanate (MDI) was the cleaner raw material for air-permeable plastic runway production, because the environmental impact of producing an equal mass of MDI was 39%-89% of that by toluene diisocyanate. Thus, this LCA study presents a strategy for the sustainable improvement of air-permeable plastic runway production and also proposes policy recommendations for decision makers.
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Affiliation(s)
- Yi Zhang
- College of the Environment & Ecology, Xiamen University, Xiang'an South Road, Xiang'an District, Xiamen 361102, China.
| | - Feng Li
- Taizhou Ecological Environment Bureau, Yonghui Road, Hailing District, Taizhou City, Jiangsu Province, 225300, China
| | - Najun Peng
- College of the Environment & Ecology, Xiamen University, Xiang'an South Road, Xiang'an District, Xiamen 361102, China.
| | - Lihong Peng
- College of the Environment & Ecology, Xiamen University, Xiang'an South Road, Xiang'an District, Xiamen 361102, China.
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3
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Wisnewski AV, Liu J. Molecular Characterization and Experimental Utility of Monoclonal Antibodies with Specificity for Aliphatic Di- and Polyisocyanates. Monoclon Antib Immunodiagn Immunother 2020; 39:66-73. [PMID: 32302507 PMCID: PMC7310211 DOI: 10.1089/mab.2020.0006] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2020] [Accepted: 03/16/2020] [Indexed: 11/12/2022] Open
Abstract
Aliphatic di- and polyisocyanates are crucial chemical ingredients in many industrial processes and are a well-recognized cause of occupational asthma. Serologic detection of "chemical epitopes" in biological samples could serve as an exposure surveillance approach toward disease prevention, and thus we sought to generate aliphatic isocyanate-specific monoclonal antibodies (mAbs). Three hybridomas were generated from Balb/c mice immunized with a commercial product containing a combination of uretdione, homopolymer, and monomeric forms of hexamethylene diisocyanate (HDI). Three stable hybridomas were subcloned by limiting dilution, two secreting IgG1κ and one secreting IgMκ mAb that bind aliphatic di- and polyisocyanates (conjugated to albumin), but not aromatic toluene or methylene diphenyl diisocyanate (TDI or MDI). Each mAb demonstrates slight differences in epitope specificity, for example, recognition of hydrogenated MDI (HMDI) or different carrier proteins (transferrin, actin) reacted with vapor phase HDI, and is encoded by unique recombination of different germline antibody genes, with distinct complementary determining regions. By western blot, all three mAbs detect a molecule with characteristics of an albumin adduct uniquely in urine from mice skin exposed to a mixture of aliphatic di- and polyisocyanate. Together, the data define molecular determinants of humoral immune recognition of aliphatic di- and polyisocyanates through new mAbs, which will serve as useful research reagents and may be applicable to future exposure surveillance efforts.
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Affiliation(s)
- Adam V. Wisnewski
- Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut, USA
| | - Jian Liu
- Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut, USA
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4
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Pollaris L, Van Den Broucke S, Decaesteker T, Cremer J, Seys S, Devos FC, Provoost S, Maes T, Verbeken E, Vande Velde G, Nemery B, Hoet PHM, Vanoirbeek JAJ. Dermal exposure determines the outcome of repeated airway exposure in a long-term chemical-induced asthma-like mouse model. Toxicology 2019; 421:84-92. [PMID: 31071364 DOI: 10.1016/j.tox.2019.05.001] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2019] [Revised: 04/24/2019] [Accepted: 05/05/2019] [Indexed: 12/28/2022]
Abstract
BACKGROUND Exposure to diisocyanates is an important cause of occupational asthma (OA) in the industrialized world. Since OA occurs after long-term exposure to diisocyanates, we developed a chronic mouse model of chemical-induced asthma where toluene diisocyanate (TDI) was administered at two different exposure sites. OBJECTIVES Evaluating the effect of long-term respiratory isocyanate exposure - with or without prior dermal exposure- on sensitization, inflammatory responses and airway hyperreactivity (AHR). METHODS On days 1 and 8, BALB/c mice were dermally treated (20 μl/ear) with 0.5% 2,4-toluene diisocyanate TDI or the vehicle acetone olive oil (AOO) (3:2). Starting from day 15, mice received intranasal instillations with 0.1% TDI of vehicle five times in a week, for five successive weeks. One day after the last instillation airway hyperreactivity (AHR) to methacholine was assessed, followed by an evaluation of pulmonary inflammation and structural lung changes. Immune-related parameters were assessed in the lungs (BAL and tissue), blood, cervical- and auricular lymph nodes. RESULTS Mice repeatedly intranasally exposed to TDI showed systemic sensitization and a mixed Th1/Th2 type immune response, without the presence of AHR. However, when mice are first dermally sensitized with TDI, followed by repeated intranasal TDI challenges, this results in a pronounced Th2 response and AHR. CONCLUSION Dermal exposure to TDI determines airway hyperreactivity after repeated airway exposure to TDI.
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Affiliation(s)
- Lore Pollaris
- Centre for Environment and Health, Department of Public Health and Primary Care, University of Leuven, Leuven, Belgium
| | - Sofie Van Den Broucke
- Centre for Environment and Health, Department of Public Health and Primary Care, University of Leuven, Leuven, Belgium
| | - Tatjana Decaesteker
- Laboratory of Respiratory Diseases, Department of Chronic Diseases, Metabolism and Ageing, University of Leuven, Leuven, Belgium
| | - Jonathan Cremer
- Laboratory of Clinical Immunology, Department of Microbiology and Immunology, University of Leuven, Leuven, Belgium
| | - Sven Seys
- Laboratory of Clinical Immunology, Department of Microbiology and Immunology, University of Leuven, Leuven, Belgium
| | - Fien C Devos
- Centre for Environment and Health, Department of Public Health and Primary Care, University of Leuven, Leuven, Belgium
| | - Sharen Provoost
- Laboratory for Translational Research in Obstructive Pulmonary Diseases, Department of Respiratory Medicine, Ghent University Hospital, Ghent, Belgium
| | - Tania Maes
- Laboratory for Translational Research in Obstructive Pulmonary Diseases, Department of Respiratory Medicine, Ghent University Hospital, Ghent, Belgium
| | - Erik Verbeken
- Translational Cell and Tissue Research, Department of Imaging and Pathology, University of Leuven, Leuven, Belgium
| | | | - Benoit Nemery
- Centre for Environment and Health, Department of Public Health and Primary Care, University of Leuven, Leuven, Belgium
| | - Peter H M Hoet
- Centre for Environment and Health, Department of Public Health and Primary Care, University of Leuven, Leuven, Belgium
| | - Jeroen A J Vanoirbeek
- Centre for Environment and Health, Department of Public Health and Primary Care, University of Leuven, Leuven, Belgium.
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5
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Wisnewski AV, Nassar AF, Liu J, Bello D. Dilysine-Methylene Diphenyl Diisocyanate (MDI), a Urine Biomarker of MDI Exposure? Chem Res Toxicol 2019; 32:557-565. [PMID: 30724074 PMCID: PMC6465083 DOI: 10.1021/acs.chemrestox.8b00262] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Biomonitoring of methylene diphenyl diisocyanate (MDI) in urine may be useful in industrial hygiene and exposure surveillance approaches toward disease (occupational asthma) prevention and in understanding pathways by which the internalized chemical is excreted. We explored possible urine biomarkers of MDI exposure in mice after respiratory tract exposure to MDI, as glutathione (GSH) reaction products (MDI-GSH), and after skin exposure to MDI dissolved in acetone. LC-MS analyses of urine identified a unique m/ z 543.29 [M + H]+ ion from MDI-exposed mice but not from controls. The m/ z 543.29 [M + H]+ ion was detectable within 24 h of a single MDI skin exposure and following multiple respiratory tract exposures to MDI-GSH reaction products. The m/ z 543.29 [M + H]+ ion possessed properties of dilysine-MDI, including (a) an isotope distribution pattern for a molecule with the chemical formula C27H38N6O6, (b) the expected collision-induced dissociation (CID) fragmentation pattern upon MS/MS, and (c) a retention time in reversed-phase LC-MS identical to that of synthetic dilysine-MDI. Further MDI-specific Western blot studies suggested albumin (which contains multiple dilysine sites susceptible to MDI carbamylation) as a possible source for dilysine-MDI and the presence of MDI-conjugated albumin in urine up to 6 days after respiratory tract exposure. Two additional [M + H]+ ions ( m/ z 558.17 and 863.23) were found exclusively in urine of mice exposed to MDI-GSH via the respiratory tract and possessed characteristics of previously described cyclized MDI-GSH and oxidized glutathione (GSSG)-MDI conjugates, respectively. Together the data identify urinary biomarkers of MDI exposure in mice and possible guidance for future translational investigation.
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Affiliation(s)
- Adam V. Wisnewski
- Department of Internal Medicine, Yale University, New Haven, CT, USA
| | - Ala F Nassar
- Department of Internal Medicine, Yale University, New Haven, CT, USA
| | - Jian Liu
- Department of Internal Medicine, Yale University, New Haven, CT, USA
| | - Dhimiter Bello
- Department of Public Health, University of Massachusetts, Lowell, MA, USA
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6
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Hettick JM, Law BF, Lin CC, Wisnewski AV, Siegel PD. Mass spectrometry-based analysis of murine bronchoalveolar lavage fluid following respiratory exposure to 4,4'-methylene diphenyl diisocyanate aerosol. Xenobiotica 2017. [PMID: 28629263 DOI: 10.1080/00498254.2017.1344791] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
1. Diisocyanates are highly reactive electrophiles utilized in the manufacture of a wide range of polyurethane products and have been identified as causative agents of occupational allergic respiratory disease. However, in spite of the significant occupational health burden associated with diisocyanate-induced asthma, the mechanism of disease pathogenesis remains largely unknown. 2. To better understand the fate of inhaled diisocyanates, a nose-only aerosol exposure system was constructed and utilized to expose a BALB/c mouse model to an aerosol generated from 4,4'-methylene diphenyl diisocyanate (MDI). Tissue and bronchoalveolar lavage samples were evaluated 4 and 24 h post-exposure for evidence of diisocyanate-protein haptenation, and a label-free quantitative proteomics strategy was employed to evaluate relative changes to the protein content of the cellular fraction of the lavage fluid. 3. Following MDI aerosol exposure, expression of the number of proteins with immunological or xenobiotic metabolism relevance is increased, including endoplasmin, cytochrome P450 and argininosuccinate synthase. Western blot analysis indicated MDI-conjugated protein in the lavage fluid, which was identified as serum albumin. 4. Tandem mass spectrometry analysis of MDI-albumin revealed MDI conjugation occurs at a dilysine motif at Lys525, as well as at a glutamine-lysine motif at Lys414, in good agreement with previously published in vitro data on diisocyanate-conjugated serum albumin.
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Affiliation(s)
- Justin M Hettick
- a Allergy and Clinical Immunology Branch, Health Effects Laboratory Division, National Institute for Occupational Safety and Health , Morgantown , WV , USA and
| | - Brandon F Law
- a Allergy and Clinical Immunology Branch, Health Effects Laboratory Division, National Institute for Occupational Safety and Health , Morgantown , WV , USA and
| | - Chen-Chung Lin
- a Allergy and Clinical Immunology Branch, Health Effects Laboratory Division, National Institute for Occupational Safety and Health , Morgantown , WV , USA and
| | | | - Paul D Siegel
- a Allergy and Clinical Immunology Branch, Health Effects Laboratory Division, National Institute for Occupational Safety and Health , Morgantown , WV , USA and
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7
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Hagerman LM, Law BF, Bledsoe TA, Hettick JM, Kashon ML, Lemons AR, Wisnewski AV, Siegel PD. The influence of diisocyanate antigen preparation methodology on monoclonal and serum antibody recognition. JOURNAL OF OCCUPATIONAL AND ENVIRONMENTAL HYGIENE 2016; 13:829-839. [PMID: 27124286 PMCID: PMC5016257 DOI: 10.1080/15459624.2016.1183013] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Exposure to diisocyanates (dNCOs), such as methylene diphenyl diisocyanate (MDI) can cause occupational asthma (OA). Currently, lab tests for dNCO specific IgE are specific, but not sensitive, which limits their utility in diagnosing dNCO asthma. This may be due to variable preparation and poor characterization of the standard antigens utilized in these assays. The aim of this study was to produce and characterize a panel of antigens prepared using three different commonly employed methods and one novel method. The conjugates were examined for recognition by anti-MDI monoclonal antibodies (mAbs) in varying enzyme linked immunosorbant assay (ELISA) formats, extent of crosslinking, total amount of MDI, the sites of MDI conjugation, relative shape/charge, and reactivity with human serum with antibodies from sensitized, exposed workers. Results indicate that while there are minimal differences in the total amount of MDI conjugated, the extent of crosslinking, and the conjugation sites, there are significant differences in the recognition of differently prepared conjugates by mAbs. Native and denaturing polyacrylamide gel electrophoresis demonstrate differences in the mobility of different conjugates, indicative of structural changes that are likely important for antigenicity. While mAbs exhibited differential binding to different conjugates, polyclonal serum antibodies from MDI exposed workers exhibited equivalent binding to different conjugates by ELISA. While differences in the recognition of the different conjugates exist by mAb detection, differences in antigenicity could not be detected using human serum from MDI-sensitized individuals. Thus, although dNCO conjugate preparation can, depending on the immunoassay platform, influence binding of specific antibody clones, serologic detection of the dNCO-exposure-induced polyclonal antibody response may be less sensitive to these differences.
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Affiliation(s)
- Lauren M Hagerman
- a Allergy and Clinical Immunology Branch, Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention , Morgantown West Virginia
| | - Brandon F Law
- a Allergy and Clinical Immunology Branch, Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention , Morgantown West Virginia
| | - Toni A Bledsoe
- a Allergy and Clinical Immunology Branch, Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention , Morgantown West Virginia
| | - Justin M Hettick
- a Allergy and Clinical Immunology Branch, Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention , Morgantown West Virginia
| | - Michael L Kashon
- b Biostatistics and Epidemiology Branch, Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention , Morgantown , West Virginia
| | - Angela R Lemons
- a Allergy and Clinical Immunology Branch, Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention , Morgantown West Virginia
| | - Adam V Wisnewski
- c Department of Internal Medicine , Yale School of Medicine , New Haven , Connecticut
| | - Paul D Siegel
- a Allergy and Clinical Immunology Branch, Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention , Morgantown West Virginia
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8
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Toluene diisocyanate and methylene diphenyl diisocyanate: asthmatic response and cross-reactivity in a mouse model. Arch Toxicol 2015; 90:1709-17. [PMID: 26468151 DOI: 10.1007/s00204-015-1606-6] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2015] [Accepted: 09/21/2015] [Indexed: 10/22/2022]
Abstract
Both 2,4-toluene diisocyanate (TDI) and 4,4-methylene diphenyl diisocyanate (MDI) can cause occupational asthma. In this study, we optimized our mouse model of chemical-induced asthma in the C57Bl/6 mice strain using the model agent TDI. Furthermore, we validated MDI in this mouse model and investigated whether cross-reactivity between TDI and MDI is present. On days 1 and 8, C57Bl/6 mice were dermally treated (20 µl/ear) with 3 % MDI, 2 % TDI or the vehicle acetone olive oil (AOO) (3:2). On day 15, they received a single oropharyngeal challenge with 0.04 % MDI, 0.01 % TDI or the vehicle AOO (4:1). One day later, airway hyperreactivity (AHR) and pulmonary inflammation in the bronchoalveolar lavage (BAL) were assessed. Furthermore, total serum IgE levels, lymphocyte subpopulations in auricular lymph nodes and cytokine levels in supernatants of lymphocytes were measured. Both dermal sensitization with TDI or MDI resulted in increased total serum IgE levels along with T and B cell proliferation in the auricular lymph nodes. The auricular lymphocytes showed an increased release of both Th2 and Th1 cytokines. Mice sensitized and challenged with either TDI or MDI showed AHR, along with a predominant neutrophil lung inflammation. Mice sensitized with MDI and challenged with TDI or the other way around showed no AHR, nor BAL inflammation. Both TDI and MDI are able to induce an asthma-like response in this mouse model. However, cross-reactivity between both diisocyanates remained absent.
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Wisnewski AV, Liu J, Colangelo CM. Glutathione reaction products with a chemical allergen, methylene-diphenyl diisocyanate, stimulate alternative macrophage activation and eosinophilic airway inflammation. Chem Res Toxicol 2015; 28:729-37. [PMID: 25635619 DOI: 10.1021/tx5005002] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Isocyanates have been a leading chemical cause of occupational asthma since their utility for generating polyurethane was first recognized over 60 years ago, yet the mechanisms of isocyanate asthma pathogenesis remain unclear. The present study provides in vivo evidence that a GSH mediated pathway underlies asthma-like eosinophilic inflammatory responses to respiratory tract isocyanate exposure. In naïve mice, a mixture of GSH reaction products with the chemical allergen, methylene-diphenyl diisocyanate (MDI), induced innate immune responses, characterized by significantly increased airway levels of Chitinase YM-1 and IL-12/IL-23β (but not α) subunit. However, in mice immunologically sensitized to MDI via prior skin exposure, identical GSH-MDI doses induced substantially greater inflammatory responses, including significantly increased airway eosinophil numbers and mucus production, along with IL-12/IL-23β, chitinases, and other indicators of alternative macrophage activation. The "self"-protein albumin in mouse airway fluid was uniquely modified by GSH-MDI at position (414)K, a preferred site of MDI reactivity on human albumin. The (414)K-MDI conjugation appears to covalently cross-link GSH to albumin via GSH's NH2-terminus, a unique conformation possibly resulting from cyclized mono(GSH)-MDI or asymmetric (S,N'-linked) bis(GSH)-MDI conjugates. Together, the data support a possible thiol mediated transcarbamoylating mechanism linking MDI exposure to pathogenic eosinophilic inflammatory responses.
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10
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Hughes MA, Carson M, Collins MA, Jolly AT, Molenaar DM, Steffens W, Swaen GMH. Does diisocyanate exposure result in neurotoxicity? Clin Toxicol (Phila) 2014; 52:242-57. [PMID: 24645904 PMCID: PMC4025582 DOI: 10.3109/15563650.2014.898769] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
CONTEXT Diisocyanates have been associated with respiratory and dermal sensitization. Limited number of case reports, and a few case studies, media, and other references suggest potential neurotoxic effects from exposures to toluene diisocyanate (TDI), 1,6 hexamethylene diisocyanate (HDI), and methylene diisocyanate (MDI). However, a systematic review of the literature evaluating the causal association on humans does not exist to support this alleged association. OBJECTIVE To perform systematic review examining the body of epidemiologic evidence and provide assessment of causal association based on principles of the Sir Austin Bradford Hill criteria or considerations for causal analysis. METHODS A comprehensive search of public databases for published abstracts, case reports, cross-sectional surveys, and cohort studies using key search terms was conducted. Additional searches included regulatory reviews, EU IUCLID and EU Risk Assessment databases, and unpublished reports in the International Isocyanate Institute database. An expert panel consisting of physicians, toxicologists, and an epidemiologist critically reviewed accepted papers, providing examination of epidemiologic evidence of each report. Finally, the Hill criteria for causation were applied to the summative analysis of identified reports to estimate probability of causal association. RESULTS Twelve papers reporting exposed populations with a variety of neurological symptoms or findings suitable for analysis were identified, including eleven case or case series reports, and one cross-sectional study. Three papers reported on the same population. Each of the papers was limited by paucity of diisocyanate exposure estimates, the presence of confounding exposures to known or suspected neurotoxicants, a lack of objective biological measures of exposure or neurotoxic effects, and lack of relative strength of association measures. Additionally, reported health symptoms and syndromes lacked consistency or specificity. No plausible mechanism of toxicity was found. Application of a predictive mathematical model for determining probability of causal association for neurotoxicity was calculated to be 21%. CONCLUSION There is insufficient evidence for a causal association of neurotoxic effects and diisocyanate exposure based on lack of evidence in all categories of the Hill criteria for causality except for temporal association of reported symptoms and alleged exposure. Future reports should attempt to address more rigorous exposure assessment and control for confounding exposures.
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Affiliation(s)
- M A Hughes
- University of Utah Rocky Mountain Center for Occupational and Environmental Health , Salt Lake City, UT , USA
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11
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Lemons AR, Siegel PD, Mhike M, Law BF, Hettick JM, Bledsoe TA, Nayak AP, Beezhold DH, Green BJ. A murine monoclonal antibody with broad specificity for occupationally relevant diisocyanates. JOURNAL OF OCCUPATIONAL AND ENVIRONMENTAL HYGIENE 2014; 11:101-110. [PMID: 24369932 PMCID: PMC4624273 DOI: 10.1080/15459624.2013.843783] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Diisocyanates (dNCOs) used in industrial applications are well known low molecular weight allergens. Occupational exposure is associated with adverse health outcomes including allergic sensitization and occupational asthma. In this study, we report the production and initial characterization of a dNCO-hapten specific murine IgM monoclonal antibody (mAb). Female BALB/c mice were immunized intraperitoneally with 25 μg of 4,4'-methylene diphenyl diisocyanate (MDI)-keyhole limpet hemocyanin. Following six biweekly booster immunizations, splenocytes were recovered and fused to Sp2/0-Ag14 murine myeloma cell line for hybridoma production. Hybridomas were then screened in a solid-phase indirect enzyme-linked immunosorbent assay (ELISA) against 40:1 4,4'-MDI- human serum albumin (HSA). mAb reactivity to dNCO-HSA conjugates and dNCO-HSA spiked human serum were characterized using a sandwich ELISA. One hybridoma produced a multimeric IgM mAb (15D4) that reacted with 4,4'-MDI-HSA. Sandwich ELISA analysis demonstrated comparable reactivity with other occupationally relevant dNCO-HSA adducts, including 2,4-toluene diisocyanate (TDI)-HSA, 2,6-TDI-HSA, and 1,6-hexamethylene diisocyanate (HDI)-HSA, but not other electrophilic chemical HSA conjugates. The limit of quantification (LOQ) of 4,4'-MDI-HSA, 2,4-TDI-HSA, 2,6-TDI-HSA, and 1,6-HDI-HSA sandwich ELISAs were 567.2, 172.7, 184.2, and 403.5 ng/mL (8.67, 2.60, 2.77, and 6.07 pmol/mL), respectively. In contrast, experiments using dNCO-supplemented human sera showed an increase in the detectable limit of the assay. A mAb has been produced that has potential utility for detecting mixed diisocyanate exposures in occupational environments. The mAb may have additional utility in the standardization of specific IgE detection immunoassays as well as chromatographic-mass spectrometric methods to enrich dNCO adducted HSA in the plasma of occupationally exposed workers.
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Affiliation(s)
- Angela R Lemons
- a Allergy and Clinical Immunology Branch, Health Effects Laboratory Division , National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention , Morgantown , West Virginia
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Wisnewski AV, Liu J, Redlich CA. Connecting glutathione with immune responses to occupational methylene diphenyl diisocyanate exposure. Chem Biol Interact 2013; 205:38-45. [PMID: 23791970 PMCID: PMC3767171 DOI: 10.1016/j.cbi.2013.06.005] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2012] [Revised: 05/12/2013] [Accepted: 06/03/2013] [Indexed: 02/04/2023]
Abstract
Methylene diphenyl diisocyanate (MDI) is among the leading chemical causes of occupational asthma world-wide, however, the mechanisms of disease pathogenesis remain unclear. This study tests the hypothesis that glutathione (GSH) reacts with MDI to form quasi-stable conjugates, capable of mediating the formation of MDI-conjugated "self" protein antigens, which may participate in pathogenic inflammatory responses. To test this hypothesis, an occupationally relevant dose of MDI (0.1%w/v) was reacted with varying concentrations of GSH (10μM-10mM), and the reaction products were characterized with regard to mass/structure, and ability to carbamoylate human albumin, a major carrier protein for MDI in vivo. LC-MS/MS analysis of GSH-MDI reaction products identified products possessing the exact mass of previously described S-linked bis(GSH)-MDI and its partial hydrolysis product, as well as novel cyclized GSH-MDI structures. Upon co-incubation of GSH-MDI reaction products with human albumin, MDI was rapidly transferred to specific lysines of albumin, and the protein's native conformation/charge was altered, based on electrophoretic mobility. Three types of modification were observed, intra-molecular MDI cross-linking, addition of partially hydrolyzed MDI, and addition of "MDI-GSH", where MDI's 2nd NCO had reacted with GSH's "N-terminus". Importantly, human albumin carbamoylated by GSH-MDI was specifically recognized by serum IgG from MDI exposed workers, with binding dependent upon the starting GSH concentration, pH, and NaCl levels. Together, the data define a non-enzymatic, thiol-mediated transcarbamoylating mechanism by which GSH may promote immune responses to MDI exposure, and identify specific factors that might further modulate this process.
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Affiliation(s)
- Adam V Wisnewski
- Department of Internal Medicine, Yale University School of Medicine, New Haven, CT, USA.
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