1
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Aleksic M, Meng X. Protein Haptenation and Its Role in Allergy. Chem Res Toxicol 2024. [PMID: 38834188 DOI: 10.1021/acs.chemrestox.4c00062] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/06/2024]
Abstract
Humans are exposed to numerous electrophilic chemicals either as medicines, in the workplace, in nature, or through use of many common cosmetic and household products. Covalent modification of human proteins by such chemicals, or protein haptenation, is a common occurrence in cells and may result in generation of antigenic species, leading to development of hypersensitivity reactions. Ranging in severity of symptoms from local cutaneous reactions and rhinitis to potentially life-threatening anaphylaxis and severe hypersensitivity reactions such as Stephen-Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN), all these reactions have the same Molecular Initiating Event (MIE), i.e. haptenation. However, not all individuals who are exposed to electrophilic chemicals develop symptoms of hypersensitivity. In the present review, we examine common chemistry behind the haptenation reactions leading to formation of neoantigens. We explore simple reactions involving single molecule additions to a nucleophilic side chain of proteins and complex reactions involving multiple electrophilic centers on a single molecule or involving more than one electrophilic molecule as well as the generation of reactive molecules from the interaction with cellular detoxification mechanisms. Besides generation of antigenic species and enabling activation of the immune system, we explore additional events which result directly from the presence of electrophilic chemicals in cells, including activation of key defense mechanisms and immediate consequences of those reactions, and explore their potential effects. We discuss the factors that work in concert with haptenation leading to the development of hypersensitivity reactions and those that may act to prevent it from developing. We also review the potential harnessing of the specificity of haptenation in the design of potent covalent therapeutic inhibitors.
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Affiliation(s)
- Maja Aleksic
- Safety and Environmental Assurance Centre, Unilever, Colworth Science Park, Sharnbrook, Bedford MK44 1LQ, U.K
| | - Xiaoli Meng
- MRC Centre for Drug Safety Science, Department of Molecular and Clinical Pharmacology, The University of Liverpool, Liverpool L69 3GE, U.K
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2
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Aleksic M, Rajagopal R, de-Ávila R, Spriggs S, Gilmour N. The skin sensitization adverse outcome pathway: exploring the role of mechanistic understanding for higher tier risk assessment. Crit Rev Toxicol 2024; 54:69-91. [PMID: 38385441 DOI: 10.1080/10408444.2024.2308816] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2023] [Accepted: 12/19/2023] [Indexed: 02/23/2024]
Abstract
For over a decade, the skin sensitization Adverse Outcome Pathway (AOP) has served as a useful framework for development of novel in chemico and in vitro assays for use in skin sensitization hazard and risk assessment. Since its establishment, the AOP framework further fueled the existing efforts in new assay development and stimulated a plethora of activities with particular focus on validation, reproducibility and interpretation of individual assays and combination of assay outputs for use in hazard/risk assessment. In parallel, research efforts have also accelerated in pace, providing new molecular and dynamic insight into key events leading to sensitization. In light of novel hypotheses emerging from over a decade of focused research effort, mechanistic evidence relating to the key events in the skin sensitization AOP may complement the tools currently used in risk assessment. We reviewed the recent advances unraveling the complexity of molecular events in sensitization and signpost the most promising avenues for further exploration and development of useful assays.
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Affiliation(s)
- Maja Aleksic
- Safety and Environmental Assurance Centre, Unilever, Sharnbrook, UK
| | - Ramya Rajagopal
- Safety and Environmental Assurance Centre, Unilever, Sharnbrook, UK
| | - Renato de-Ávila
- Safety and Environmental Assurance Centre, Unilever, Sharnbrook, UK
| | - Sandrine Spriggs
- Safety and Environmental Assurance Centre, Unilever, Sharnbrook, UK
| | - Nicola Gilmour
- Safety and Environmental Assurance Centre, Unilever, Sharnbrook, UK
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3
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Höper T, Karkossa I, Dumit VI, von Bergen M, Schubert K, Haase A. A comparative proteomics analysis of four contact allergens in THP-1 cells shows distinct alterations in key metabolic pathways. Toxicol Appl Pharmacol 2023; 475:116650. [PMID: 37541627 DOI: 10.1016/j.taap.2023.116650] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2023] [Revised: 07/21/2023] [Accepted: 07/31/2023] [Indexed: 08/06/2023]
Abstract
Allergic contact dermatitis (ACD) is the predominant form of immunotoxicity in humans. The sensitizing potential of chemicals can be assessed in vitro. However, a better mechanistic understanding could improve the current OECD-validated test battery. The aim of this study was to get insights into toxicity mechanisms of four contact allergens, p-benzoquinone (BQ), 2,4-dinitrochlorobenzene (DNCB), p-nitrobenzyl bromide (NBB) and NiSO4, by analyzing differential proteome alterations in THP-1 cells using two common proteomics workflows, stable isotope labeling by amino acids in cell culture (SILAC) and label-free quantification (LFQ). Here, SILAC was found to deliver more robust results. Overall, the four allergens induced similar responses in THP-1 cells, which underwent profound metabolic reprogramming, including a striking upregulation of the TCA cycle accompanied by pronounced induction of the Nrf2 oxidative stress response pathway. The magnitude of induction varied between the allergens with DNCB and NBB being most potent. A considerable overlap between transcriptome-based signatures of the GARD assay and the proteins identified in our study was found. When comparing the results of this study to a previous proteomics study in human primary monocyte-derived dendritic cells, we found a rather low share in regulated proteins. However, on pathway level, the overlap was high, indicating that affected pathways rather than single proteins are more eligible to investigate proteomic changes induced by contact allergens. Overall, this study confirms the potential of proteomics to obtain a profound mechanistic understanding, which may help improving existing in vitro assays for skin sensitization.
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Affiliation(s)
- Tessa Höper
- Department of Chemical and Product Safety, German Federal Institute for Risk Assessment (BfR), Berlin, Germany; Department of Clinical Pharmacy and Biochemistry, Institute of Pharmacy, Freie Universität Berlin, Berlin, Germany
| | - Isabel Karkossa
- Department of Molecular Systems Biology, UFZ, Helmholtz-Centre for Environmental Research, Leipzig, Germany
| | - Verónica I Dumit
- Department of Chemical and Product Safety, German Federal Institute for Risk Assessment (BfR), Berlin, Germany
| | - Martin von Bergen
- Department of Molecular Systems Biology, UFZ, Helmholtz-Centre for Environmental Research, Leipzig, Germany; Institute of Biochemistry, Leipzig University, Leipzig, Germany; German Centre for Integrative Biodiversity Research (iDiv) Halle-Jena-Leipzig, Leipzig, Germany
| | - Kristin Schubert
- Department of Molecular Systems Biology, UFZ, Helmholtz-Centre for Environmental Research, Leipzig, Germany
| | - Andrea Haase
- Department of Chemical and Product Safety, German Federal Institute for Risk Assessment (BfR), Berlin, Germany.
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4
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Kim SM, Studnitzer B, Esser-Kahn A. Heat Shock Protein 90's Mechanistic Role in Contact Hypersensitivity. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2022; 208:2622-2631. [PMID: 35675957 DOI: 10.4049/jimmunol.2101023] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/29/2021] [Accepted: 04/15/2022] [Indexed: 11/19/2022]
Abstract
Despite the known dangers of contact allergens and their long-lasting use as models in immunology, their molecular mode of action largely remains unknown. In this study, we report that a contact allergen, 1-chloro-2,4-dinitrobenzene (DNCB), elicits contact hypersensitivity through binding the protein we identify. Starting from an unbiased sampling of proteomics, we found nine candidate proteins with unique DNCB-modified peptide fragments. More than half of these fragments belonged to heat shock protein 90 (HSP90), a common stress-response protein and a damage-associated molecular pattern, and showed the highest probability of incidence. Inhibition and short hairpin RNA knockdown of HSP90 in human monocyte cell line THP-1 suppressed the potency of DNCB by >80%. Next, we successfully reduced DNCB-induced contact hypersensitivity in HSP90-knockout mice, which confirmed our findings. Finally, we hypothesized that DNCB-modified HSP90 activates the immune cells through HSP90's receptor, CD91. Pretreatment of CD91 in THP-1 cell lines and BALB/c mice attenuated the potency of DNCB, consistent with the result of HSP90-knockout mice. Altogether, our data show that DNCB-HSP90 binding plays a role in mediating DNCB-induced contact hypersensitivity, and the activation of CD91 by DNCB-modified HSP90 proteins could mediate this process.
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Affiliation(s)
- Seong-Min Kim
- Pritzker School of Molecular Engineering, The University of Chicago, Chicago, IL
| | - Bradley Studnitzer
- Pritzker School of Molecular Engineering, The University of Chicago, Chicago, IL
| | - Aaron Esser-Kahn
- Pritzker School of Molecular Engineering, The University of Chicago, Chicago, IL
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5
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Ndreu L, Sasse S, Karlberg AT, Karlsson I. Haptenation of Macrophage Migration Inhibitory Factor: A Potential Biomarker for Contact Hypersensitivity. FRONTIERS IN TOXICOLOGY 2022; 4:856614. [PMID: 35465102 PMCID: PMC9019732 DOI: 10.3389/ftox.2022.856614] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2022] [Accepted: 03/03/2022] [Indexed: 11/13/2022] Open
Abstract
The immunological response in contact hypersensitivity is incited by small electrophilic compounds, known as haptens, that react with endogenous proteins after skin absorption. However, the identity of hapten-modified proteins seen as immunogenic remains as yet largely unknown. In a recent study, we have for the first time identified a hapten-modified protein in the local lymph nodes of mice treated topically with the model hapten tetramethylrhodamine isothiocyanate (TRITC). The TRITC modification was located on the N-terminal proline of the protein macrophage migration inhibitory factor (MIF). The focus of the current study was to investigate the presence of the same hapten-protein conjugate in blood samples from mice treated topically with TRITC. Furthermore, TRITC modifications of the two major blood proteins, namely hemoglobin (Hb) and albumin (Alb), as well as TRITC modifications of MIF other than the N-terminal proline, were examined. Following incubation with different molar ratios of TRITC, a proteomic approach was applied to characterize conjugate formation of the three aforementioned proteins, using high resolution mass spectrometry (HRMS). The targeted screening of the TRITC-treated mice blood and lymph node samples for these sites led to the identification of only the same TRITC-MIF conjugate previously detected in the lymph nodes. No Hb and Alb conjugates were detected. Quantification of both the TRITC-modified and unmodified N-terminal peptide of MIF in blood and lymph node samples gave interesting insights of MIF’s role in murine contact hypersensitivity. Incubation of MIF with four different haptens encompassing different reactivity mechanisms and potencies, showed adduct formation at different amino acid residues, suggesting that MIF can be the preferred target for a wide variety of haptens. The present study provides essential progress toward understanding of hapten-protein conjugate formation in contact hypersensitivity and identifies hapten-modified MIF as a potential biomarker for this condition. Further investigation of MIF as a target protein can be a next step to determine if MIF is a biomarker that can be used to develop better diagnostic tools and targeted therapeutics for individuals with allergic contact dermatitis.
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Affiliation(s)
- Lorena Ndreu
- Department of Environmental Science, Stockholm University, Stockholm, Sweden
| | - Samantha Sasse
- Department of Environmental Science, Stockholm University, Stockholm, Sweden
| | - Ann-Therese Karlberg
- Department of Chemistry and Molecular Biology, Dermatochemistry, University of Gothenburg, Gothenburg, Sweden
| | - Isabella Karlsson
- Department of Environmental Science, Stockholm University, Stockholm, Sweden
- *Correspondence: Isabella Karlsson,
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6
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Bailey A, Nicholas B, Darley R, Parkinson E, Teo Y, Aleksic M, Maxwell G, Elliott T, Ardern-Jones M, Skipp P. Characterization of the Class I MHC Peptidome Resulting From DNCB Exposure of HaCaT Cells. Toxicol Sci 2021; 180:136-147. [PMID: 33372950 PMCID: PMC7916740 DOI: 10.1093/toxsci/kfaa184] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Skin sensitization following the covalent modification of proteins by low molecular weight chemicals (haptenation) is mediated by cytotoxic T lymphocyte (CTL) recognition of human leukocyte antigen (HLA) molecules presented on the surface of almost all nucleated cells. There exist 3 nonmutually exclusive hypotheses for how haptens mediate CTL recognition: direct stimulation by haptenated peptides, hapten modification of HLA leading to an altered HLA-peptide repertoire, or a hapten altered proteome leading to an altered HLA-peptide repertoire. To shed light on the mechanism underpinning skin sensitization, we set out to utilize proteomic analysis of keratinocyte presented antigens following exposure to 2,4-dinitrochlorobenzene (DNCB). We show that the following DNCB exposure, cultured keratinocytes present cysteine haptenated (dinitrophenylated) peptides in multiple HLA molecules. In addition, we find that one of the DNCB modified peptides derives from the active site of cytosolic glutathione-S transferase-ω. These results support the current view that a key mechanism of skin sensitization is stimulation of CTLs by haptenated peptides. Data are available via ProteomeXchange with identifier PXD021373.
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Affiliation(s)
- Alistair Bailey
- Centre for Proteomic Research, Biological Sciences and Institute for Life Sciences, University of Southampton, Southampton SO17 1BJ, UK.,Centre for Cancer Immunology and Institute for Life Sciences, Faculty of Medicine, University of Southampton, Southampton SO16 6YD, UK
| | - Ben Nicholas
- Centre for Proteomic Research, Biological Sciences and Institute for Life Sciences, University of Southampton, Southampton SO17 1BJ, UK.,Centre for Cancer Immunology and Institute for Life Sciences, Faculty of Medicine, University of Southampton, Southampton SO16 6YD, UK
| | - Rachel Darley
- Centre for Cancer Immunology and Institute for Life Sciences, Faculty of Medicine, University of Southampton, Southampton SO16 6YD, UK
| | - Erika Parkinson
- Centre for Proteomic Research, Biological Sciences and Institute for Life Sciences, University of Southampton, Southampton SO17 1BJ, UK
| | - Ying Teo
- Clinical and Experimental Sciences, Sir Henry Wellcome Laboratories, Faculty of Medicine, University of Southampton, Southampton SO16 6YD, UK
| | - Maja Aleksic
- Safety & Environmental Assurance Centre, Unilever, Colworth Science Park, Sharnbrook MK44 1LQ, UK
| | - Gavin Maxwell
- Safety & Environmental Assurance Centre, Unilever, Colworth Science Park, Sharnbrook MK44 1LQ, UK
| | - Tim Elliott
- Centre for Cancer Immunology and Institute for Life Sciences, Faculty of Medicine, University of Southampton, Southampton SO16 6YD, UK
| | - Michael Ardern-Jones
- Clinical and Experimental Sciences, Sir Henry Wellcome Laboratories, Faculty of Medicine, University of Southampton, Southampton SO16 6YD, UK
| | - Paul Skipp
- Centre for Proteomic Research, Biological Sciences and Institute for Life Sciences, University of Southampton, Southampton SO17 1BJ, UK
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7
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Khong MT, Berl V, Kuhn L, Hammann P, Lepoittevin JP. Chemical Modifications Induced by Phthalic Anhydride, a Respiratory Sensitizer, in Reconstructed Human Epidermis: A Combined HRMAS NMR and LC-MS/MS Proteomic Approach. Chem Res Toxicol 2021; 34:2087-2099. [PMID: 34370447 DOI: 10.1021/acs.chemrestox.1c00172] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Chemical skin and respiratory allergies are becoming a major health problem. To date our knowledge on the process of protein haptenation is still limited and mainly derived from studies performed in solution using model nucleophiles. In order to better understand chemical interactions between chemical allergens and the skin, we have investigated the reactivity of phthalic anhydride 1 (PA), a chemical respiratory sensitizer, toward reconstructed human epidermis (RHE). This study was performed using a new approach combining HRMAS NMR to investigate the in situ chemical reactivity and LC-MS/MS to identify modified epidermal proteins. In RHE, the reaction of PA appeared to be quite fast and the major product formed was phthalic acid. Two amide type adducts on lysine residues were observed and after 8h of incubation, we also observed the formation of an imide type cyclized adducts with lysine. In parallel, RHE samples topically exposed to phthalic anhydride (13C)-1 were analyzed using the shotgun proteomics method. Thus, 948 different proteins were extracted and identified, 135 of which being modified by PA, i.e., 14.2% of the extracted proteome. A total of 211 amino acids were modified by PA and validated by fragmentation spectra. We thus identified 154 modified lysines, 22 modified histidines, 30 modified tyrosines, and 5 modified arginines. The rate of modified residues, as a proportion of the total number of modifiable nucleophilic residues in RHE, was rather low (1%). At the protein level, modified proteins were mainly type I and type II keratins and other proteins which are abundant in the epidermis such as protein S100A, Caspase 14, annexin A2, serpin B3, fatty-acid binding protein 5, histone H2, H3, H4, etc. However, the most modified protein, mainly on histidine residues, was filaggrin, a protein that is of low abundance (0.0266 mol %) and rich in histidine.
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Affiliation(s)
- Minh-Thuong Khong
- University of Strasbourg, CNRS, Institute of Chemistry UMR 7177, F-67000 Strasbourg, France
| | - Valérie Berl
- University of Strasbourg, CNRS, Institute of Chemistry UMR 7177, F-67000 Strasbourg, France
| | - Lauriane Kuhn
- Plateforme Protéomique Strasbourg-Esplanade, Institut de Biologie Moléculaire et Cellulaire, CNRS FRC1589, Université de Strasbourg, F-67000 Strasbourg, France
| | - Philippe Hammann
- Plateforme Protéomique Strasbourg-Esplanade, Institut de Biologie Moléculaire et Cellulaire, CNRS FRC1589, Université de Strasbourg, F-67000 Strasbourg, France
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8
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Lepoittevin JP, Lafforgue C. Molecular Aspects in Allergic and Irritant Contact Dermatitis. Contact Dermatitis 2021. [DOI: 10.1007/978-3-030-36335-2_4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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9
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Parkinson E, Aleksic M, Kukic P, Bailey A, Cubberley R, Skipp P. Proteomic analysis of the cellular response to a potent sensitiser unveils the dynamics of haptenation in living cells. Toxicology 2020; 445:152603. [DOI: 10.1016/j.tox.2020.152603] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2020] [Revised: 09/22/2020] [Accepted: 09/23/2020] [Indexed: 01/09/2023]
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10
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Srour H, Moussallieh FM, Elbayed K, Giménez-Arnau E, Lepoittevin JP. In Situ Alkylation of Reconstructed Human Epidermis by Methyl Methanesulfonate: A Quantitative HRMAS NMR Chemical Reactivity Mapping. Chem Res Toxicol 2020; 33:3023-3030. [PMID: 33190492 DOI: 10.1021/acs.chemrestox.0c00362] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Allergic contact dermatitis (ACD) is a reaction of the immune system resulting from skin sensitization to an exogenous hazardous chemical and leading to the activation of antigen-specific T-lymphocytes. The adverse outcome pathway (AOP) for skin sensitization identified four key events (KEs) associated with the mechanisms of this pathology, the first one being the ability of skin chemical sensitizers to modify epidermal proteins to form antigenic structures that will further trigger the immune system. So far, these interactions have been studied in solution using model nucleophiles such as amino acids or peptides. As a part of our efforts to better understand chemistry taking place during the sensitization process, we have developed a method based on the use of high-resolution magic angle spinning (HRMAS) NMR to monitor in situ the reactions of 13C substituted chemical sensitizers with nucleophilic amino acids of epidermal proteins in reconstructed human epidermis. A quantitative approach, developed so far for liquid NMR applications, has not been developed to our knowledge in a context of a semisolid nonanisotropic environment like the epidermis. We now report a quantitative chemical reactivity mapping of methyl methanesulfonate (MMS), a sensitizing methylating agent, in reconstructed human epidermis by quantitative HRMAS (qHRMAS) NMR. First, the haptenation process appeared to be much faster in RHE than in solution with a maximum concentration of adducts reached between 4 and 8 h. Second, it was observed that the concentration of cysteine adducts did not significantly increase with the dose (2.07 nmol/mg at 0.4 M and 2.14 nmol/mg at 1 M) nor with the incubation time (maximum of 2.27 nmol/mg at 4 h) compared to other nucleophiles, indicating a fast reaction and a potential saturation of targets. Third, when increasing the exposure dose, we observed an increase of adducts up to 12.5 nmol/mg of RHE, excluding cysteine adducts, for 3112 μg/cm2 (1 M solution) of (13C)MMS. This methodology applied to other skin sensitizers could allow for better understanding of the potential links between the amount of chemical modifications formed in the epidermis in relation to exposure and the sensitization potency.
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Affiliation(s)
- Hassan Srour
- CNRS, Institute of Chemistry UMR 7177, University of Strasbourg, F-67000 Strasbourg, France
| | | | - Karim Elbayed
- CNRS, ICube UMR 7357, University of Strasbourg, F-67000 Strasbourg, France
| | - Elena Giménez-Arnau
- CNRS, Institute of Chemistry UMR 7177, University of Strasbourg, F-67000 Strasbourg, France
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11
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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: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
![]()
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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12
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Parkinson E, Aleksic M, Arthur R, Regufe Da Mota S, Cubberley R, Skipp PJ. Proteomic analysis of haptenation by skin sensitisers: Diphencyprone and ethyl acrylate. Toxicol In Vitro 2020; 62:104697. [DOI: 10.1016/j.tiv.2019.104697] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2019] [Revised: 10/16/2019] [Accepted: 10/21/2019] [Indexed: 02/06/2023]
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13
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Lepoittevin JP, Lafforgue C. Molecular Aspects in Allergic and Irritant Contact Dermatitis. Contact Dermatitis 2020. [DOI: 10.1007/978-3-319-72451-5_4-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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14
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Parkinson E, Aleksic M, Cubberley R, Kaur-Atwal G, Vissers JPC, Skipp P. Determination of Protein Haptenation by Chemical Sensitizers Within the Complexity of the Human Skin Proteome. Toxicol Sci 2018; 162:429-438. [PMID: 29267982 PMCID: PMC5889026 DOI: 10.1093/toxsci/kfx265] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Skin sensitization associated with the development of allergic contact dermatitis occurs via a number of specific key events at the cellular level. The molecular initiating event (MIE), the first in the sequence of these events, occurs after exposure of the skin to an electrophilic chemical, causing the irreversible haptenation of proteins within skin. Characterization of this MIE is a key step in elucidating the skin sensitization adverse outcome pathway and is essential to providing parameters for mathematical models to predict the capacity of a chemical to cause sensitization. As a first step to addressing this challenge, we have exposed complex protein lysates from a keratinocyte cell line and human skin tissue with a range of well characterized sensitizers, including dinitrochlorobenzene, 5-chloro-2-methylisothiazol-3-one, cinnamaldehyde, and the non (or weak) sensitizer 6-methyl coumarin. Using a novel stable isotope labeling approach combined with ion mobility-assisted data independent mass spectrometry (HDMSE), we have characterized the haptenome for these sensitizers. Although a significant proportion of highly abundant proteins were haptenated, we also observed the haptenation of low abundant proteins by all 3 of the chemical sensitizers tested, indicating that within a complex protein background, protein abundance is not the sole determinant driving haptenation, highlighting a relationship to tertiary protein structure and the amino acid specificity of these chemical sensitizers and sensitizer potency.
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Affiliation(s)
- Erika Parkinson
- Centre for Biological Sciences
- Centre for Proteomic Research, Institute for Life Sciences, University of Southampton, Southampton SO17 1BJ, UK
| | - Maja Aleksic
- Safety & Environmental Assurance Centre, Unilever, Colworth Science Park, Sharnbrook MK44 1LQ, UK
| | - Richard Cubberley
- Safety & Environmental Assurance Centre, Unilever, Colworth Science Park, Sharnbrook MK44 1LQ, UK
| | | | | | - Paul Skipp
- Centre for Biological Sciences
- Centre for Proteomic Research, Institute for Life Sciences, University of Southampton, Southampton SO17 1BJ, UK
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15
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Karlsson I, Samuelsson K, Simonsson C, Stenfeldt AL, Nilsson U, Ilag LL, Jonsson C, Karlberg AT. The Fate of a Hapten - From the Skin to Modification of Macrophage Migration Inhibitory Factor (MIF) in Lymph Nodes. Sci Rep 2018; 8:2895. [PMID: 29440696 PMCID: PMC5811565 DOI: 10.1038/s41598-018-21327-8] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2017] [Accepted: 01/31/2018] [Indexed: 12/02/2022] Open
Abstract
Skin (contact) allergy, the most prevalent form of immunotoxicity in humans, is caused by low molecular weight chemicals (haptens) that penetrate stratum corneum and modify endogenous proteins. The fate of haptens after cutaneous absorption, especially what protein(s) they react with, is largely unknown. In this study the fluorescent hapten tetramethylrhodamine isothiocyanate (TRITC) was used to identify hapten-protein conjugates in the local lymph nodes after topical application, as they play a key role in activation of the adaptive immune system. TRITC interacted with dendritic cells but also with T and B cells in the lymph nodes as shown by flow cytometry. Identification of the most abundant TRITC-modified protein in lymph nodes by tandem mass spectrometry revealed TRITC-modification of the N-terminal proline of macrophage migration inhibitory factor (MIF) – an evolutionary well-conserved protein involved in cell-mediated immunity and inflammation. This is the first time a hapten-modified protein has been identified in lymph nodes after topical administration of the hapten. Most haptens are electrophiles and can therefore modify the N-terminal proline of MIF, which has an unusually reactive amino group under physiological conditions; thus, modification of MIF by haptens may have an immunomodulating role in contact allergy as well as in other immunotoxicity reactions.
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Affiliation(s)
- Isabella Karlsson
- Department of Environmental Science and Analytical Chemistry, Stockholm University, Stockholm, Sweden.
| | - Kristin Samuelsson
- Department of Chemistry and Molecular Biology, Dermatochemistry, University of Gothenburg, Gothenburg, Sweden
| | - Carl Simonsson
- Department of Chemistry and Molecular Biology, Dermatochemistry, University of Gothenburg, Gothenburg, Sweden
| | - Anna-Lena Stenfeldt
- Department of Chemistry and Molecular Biology, Dermatochemistry, University of Gothenburg, Gothenburg, Sweden
| | - Ulrika Nilsson
- Department of Environmental Science and Analytical Chemistry, Stockholm University, Stockholm, Sweden
| | - Leopold L Ilag
- Department of Environmental Science and Analytical Chemistry, Stockholm University, Stockholm, Sweden
| | - Charlotte Jonsson
- Department of Chemistry and Molecular Biology, Dermatochemistry, University of Gothenburg, Gothenburg, Sweden
| | - Ann-Therese Karlberg
- Department of Chemistry and Molecular Biology, Dermatochemistry, University of Gothenburg, Gothenburg, Sweden
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16
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Abstract
Contact sensitization is the initial process involved in the development of an allergic reaction to xenobiotic environmental substances. Here, we briefly describe the differences between irritant and allergic contact dermatitis. Then, we highlight the essential steps involved in the development of an ACD reaction, i.e., the protein binding of haptens, genetic factors influencing the penetration of sensitizers into the skin, the different mechanisms driving the initial development of an inflammatory cytokine micromilieu enabling the full maturation of dendritic cells, the role of pre- and pro-haptens, antigen presentation and T cell activation via MHC and CD1 molecules, dendritic cell (DC) migration, and potential LC contribution as well as the different T cell subsets involved in ACD. In addition, we discuss the latest publications regarding factors that might influence the sensitizing potential such as repeated sensitizer application, penetration enhancers, humidity of the skin, microbiota, Tregs, and phthalates. Last but not least, we briefly touch upon novel targets for drug development that might serve as treatment options for ACD.
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Affiliation(s)
- Philipp R Esser
- Allergy Research Group, Department of Dermatology, Medical Center-University of Freiburg, Faculty of Medicine, University of Freiburg, Hauptstrasse 7, 79104, Freiburg im Breisgau, Germany.
| | - Stefan F Martin
- Allergy Research Group, Department of Dermatology, Medical Center-University of Freiburg, Faculty of Medicine, University of Freiburg, Hauptstrasse 7, 79104, Freiburg im Breisgau, Germany
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17
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Höper T, Mussotter F, Haase A, Luch A, Tralau T. Application of proteomics in the elucidation of chemical-mediated allergic contact dermatitis. Toxicol Res (Camb) 2017; 6:595-610. [PMID: 30090528 PMCID: PMC6062186 DOI: 10.1039/c7tx00058h] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2017] [Accepted: 06/07/2017] [Indexed: 12/23/2022] Open
Abstract
Allergic contact dermatitis (ACD) is a widespread hypersensitivity reaction of the skin. The cellular mechanisms underlying its development are complex and involve close interaction of different cell types of the immune system. It is this very complexity which has long prevented straightforward replacement of the corresponding regulatory in vivo tests. Recent efforts have already resulted in the development of several in vitro testing alternatives that address key steps of ACD. Yet identification of suitable biomarkers is still a subject of intense research. Search strategies for the latter encompass transcriptomics, proteomics as well as metabolomics approaches. The scope of this review shall be the application and use of proteomics in the context of ACD. This includes highlighting relevant aspects of the molecular and cellular mechanisms underlying ACD, the exploitation of these mechanisms for testing and biomarkers (e.g., in the context of the OECD's adverse outcome pathway initiative) as well as an outlook on emerging proteome targets, for example during the allergen-induced activation of dendritic cells (DCs).
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Affiliation(s)
- Tessa Höper
- German Federal Institute for Risk Assessment , Department of Chemical and Product Safety , Max-Dohrn-Strasse 8-10 , 10589 Berlin , Germany .
| | - Franz Mussotter
- German Federal Institute for Risk Assessment , Department of Chemical and Product Safety , Max-Dohrn-Strasse 8-10 , 10589 Berlin , Germany .
| | - Andrea Haase
- German Federal Institute for Risk Assessment , Department of Chemical and Product Safety , Max-Dohrn-Strasse 8-10 , 10589 Berlin , Germany .
| | - Andreas Luch
- German Federal Institute for Risk Assessment , Department of Chemical and Product Safety , Max-Dohrn-Strasse 8-10 , 10589 Berlin , Germany .
| | - Tewes Tralau
- German Federal Institute for Risk Assessment , Department of Chemical and Product Safety , Max-Dohrn-Strasse 8-10 , 10589 Berlin , Germany .
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18
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Oliva M, Renert-Yuval Y, Guttman-Yassky E. The 'omics' revolution: redefining the understanding and treatment of allergic skin diseases. Curr Opin Allergy Clin Immunol 2016; 16:469-76. [PMID: 27490125 DOI: 10.1097/aci.0000000000000306] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
PURPOSE OF REVIEW To evaluate how the genomic, transcriptomic, and proteomic profiles of allergic skin diseases, like atopic dermatitis and allergic contact dermatitis, contribute to their understanding and promote their therapeutic development. RECENT FINDINGS The '-omics' revolution has facilitated the quantification of inflammatory skin diseases at the molecular level, expanding our understanding of disease pathogenesis. It has also greatly expanded once-limited treatment options and improved the ability to define posttreatment improvements, beyond clinical scores. The findings on the genomic/transcriptomic level are also complemented by proteomic data, contributing to the understanding of the later changes taking place in the final stages of protein formation. Atopic dermatitis is defined as a Th2/Th22 polarized disease with some contributions of Th17 and Th1 pathways. In atopic dermatitis, studies of biologics and small molecules, targeting specific pathways upregulated in atopic dermatitis, seem to provide well tolerated alternatives to conventional immunosuppressive therapies (i.e. corticosteroids and cyclosporine A), particularly for severe patients. Allergic contact dermatitis is defined as having Th1/Th17-centered inflammation, especially with nickel-induced disease, but additional pathways, including Th2 and Th22, are upregulated with other allergens (i.e. fragrance). SUMMARY Supplementing studies of allergic skin diseases with '-omics' approaches are transforming the pathogenic understanding, diagnosis and, perhaps, also the treatment of these diseases.
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Affiliation(s)
- Margeaux Oliva
- aDepartment of Dermatology and the Laboratory for Inflammatory Skin Diseases, Icahn School of Medicine at Mount Sinai, New York, New York, USA bDepartment of Dermatology, Hadassah-Hebrew University Medical Center, Jerusalem, Israel cLaboratory for Investigative Dermatology, The Rockefeller University, New York, New York, USA *Margeaux Oliva and Yael Renert-Yuval contributed equally to the article
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19
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Spriggs S, Sheffield D, Olayanju A, Kitteringham NR, Naisbitt DJ, Aleksic M. Effect of Repeated Daily Dosing with 2,4-Dinitrochlorobenzene on Glutathione Biosynthesis and Nrf2 Activation in Reconstructed Human Epidermis. Toxicol Sci 2016; 154:5-15. [PMID: 27492222 DOI: 10.1093/toxsci/kfw140] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
Glutathione (GSH) plays a major role in skin detoxification processes due to its ability to conjugate electrophilic exogenous compounds with, and sometimes without, catalysis by glutathione-s-transferase (GST). GST activity has been demonstrated both in skin and in most in vitro skin equivalents but so far studies have focussed on chemical clearance (conjugate identification and rate of conjugation) and did not consider the GSH lifecycle (conjugation, recycling, synthesis). We used the model skin sensitizer 2,4-dinitrochlorobenzene (DNCB) to investigate the effects of chemical exposure on GSH lifecycle in reconstructed human epidermis (RHE). We demonstrated that the RHE model is suitable to carry out repeated cycles of 2-h exposure to DNCB over a 3-day period. After each exposure to DNCB, the level of GSH is diminished in a dose dependent manner. After a 22-h recovery period, GSH is replenished back to initial levels. Accumulation of the nuclear factor E2-related factor 2 (Nrf2) in the cytosol also occurs within the 2 h of exposure to DNCB but returns to baseline during each recovery period, demonstrating that activation of the Nrf2 signaling pathway offers a rapid response to chemical stress. The amount of dinitrophenyl-glutathione (DNP-SG) formed with DNCB (1) increased between the first and second exposure and (2) reached a plateau between the second and third exposure. Collectively, these data suggest that the metabolic capacity of skin may not be fixed in time but defence mechanisms might be activated in response to exposure to exogenous compounds, resulting in their accelerated clearance.
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Affiliation(s)
- Sandrine Spriggs
- *Unilever, Safety and Environmental Assurance Centre, Colworth Science Park, Sharnbrook, Bedfordshire MK44 1LQ, UK;
| | - David Sheffield
- *Unilever, Safety and Environmental Assurance Centre, Colworth Science Park, Sharnbrook, Bedfordshire MK44 1LQ, UK
| | - Adedamola Olayanju
- Department of Molecular and Clinical Pharmacology, MRC Centre for Drug Safety Science, the University of Liverpool, Sherrington Building, Ashton Street, Liverpool L69 3GE, UK
| | - Neil R Kitteringham
- Department of Molecular and Clinical Pharmacology, MRC Centre for Drug Safety Science, the University of Liverpool, Sherrington Building, Ashton Street, Liverpool L69 3GE, UK
| | - Dean J Naisbitt
- Department of Molecular and Clinical Pharmacology, MRC Centre for Drug Safety Science, the University of Liverpool, Sherrington Building, Ashton Street, Liverpool L69 3GE, UK
| | - Maja Aleksic
- *Unilever, Safety and Environmental Assurance Centre, Colworth Science Park, Sharnbrook, Bedfordshire MK44 1LQ, UK
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20
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Walker V, Mills GA, Anderson ME, Ingle BL, Jackson JM, Moss CL, Sharrod-Cole H, Skipp PJ. The acetaminophen metabolite N-acetyl-p-benzoquinone imine (NAPQI) inhibits glutathione synthetase in vitro; a clue to the mechanism of 5-oxoprolinuric acidosis? Xenobiotica 2016; 47:164-175. [PMID: 27086508 DOI: 10.3109/00498254.2016.1166533] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
1. Metabolic acidosis due to accumulation of l-5-oxoproline is a rare, poorly understood, disorder associated with acetaminophen treatment in malnourished patients with chronic morbidity. l-5-Oxoprolinuria signals abnormal functioning of the γ-glutamyl cycle, which recycles and synthesises glutathione. Inhibition of glutathione synthetase (GS) by N-acetyl-p-benzoquinone imine (NAPQI) could contribute to 5-oxoprolinuric acidosis in such patients. We investigated the interaction of NAPQI with GS in vitro. 2. Peptide mapping of co-incubated NAPQI and GS using mass spectrometry demonstrated binding of NAPQI with cysteine-422 of GS, which is known to be essential for GS activity. Computational docking shows that NAPQI is properly positioned for covalent bonding with cysteine-422 via Michael addition and hence supports adduct formation. 3. Co-incubation of 0.77 μM of GS with NAPQI (25-400 μM) decreased enzyme activity by 16-89%. Inhibition correlated strongly with the concentration of NAPQI and was irreversible. 4. NAPQI binds covalently to GS causing irreversible enzyme inhibition in vitro. This is an important novel biochemical observation. It is the first indication that NAPQI may inhibit glutathione synthesis, which is pivotal in NAPQI detoxification. Further studies are required to investigate its biological significance and its role in 5-oxoprolinuric acidosis.
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Affiliation(s)
- Valerie Walker
- a Department of Clinical Biochemistry , University Hospital Southampton NHS Foundation Trust , Southampton , UK
| | - Graham A Mills
- b School of Pharmacy and Biomedical Sciences, University of Portsmouth , Portsmouth , UK
| | - Mary E Anderson
- c Department of Chemistry and Biochemistry , Texas Woman's University , Denton , TX , USA
| | - Brandall L Ingle
- d Department of Chemistry , Center for Advanced Scientific Computing and Modeling, University of North Texas , Denton , TX , USA
| | - John M Jackson
- e NIHR Southampton Biomedical Research Centre, Southampton General Hospital , Southampton , UK , and
| | - Charlotte L Moss
- f Centre for Proteomic Research and Biological Sciences, University of Southampton , Southampton , UK
| | - Hayley Sharrod-Cole
- a Department of Clinical Biochemistry , University Hospital Southampton NHS Foundation Trust , Southampton , UK
| | - Paul J Skipp
- f Centre for Proteomic Research and Biological Sciences, University of Southampton , Southampton , UK
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21
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Peptide Reactivity of Isothiocyanates--Implications for Skin Allergy. Sci Rep 2016; 6:21203. [PMID: 26883070 PMCID: PMC4756319 DOI: 10.1038/srep21203] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2015] [Accepted: 01/15/2016] [Indexed: 11/29/2022] Open
Abstract
Skin allergy is a chronic condition that affects about 20% of the population of the western world. This disease is caused by small reactive compounds, haptens, able to penetrate into the epidermis and modify endogenous proteins, thereby triggering an immunogenic reaction. Phenyl isothiocyanate (PITC) and ethyl isothiocyanate (EITC) have been suggested to be responsible for allergic skin reactions to chloroprene rubber, the main constituent of wetsuits, orthopedic braces, and many types of sports gear. In the present work we have studied the reactivity of the isothiocyanates PITC, EITC, and tetramethylrhodamine-6-isothiocyanate (6-TRITC) toward peptides under aqueous conditions at physiological pH to gain information about the types of immunogenic complexes these compounds may form in the skin. We found that all three compounds reacted quickly with cysteine moieties. For PITC and 6-TRITC the cysteine adducts decomposed over time, while stable adducts with lysine were formed. These experimental findings were verified by DFT calculations. Our results may suggest that the latter are responsible for allergic reactions to isothiocyanates. The initial adduct formation with cysteine residues may still be of great importance as it prevents hydrolysis and facilitates the transport of isothiocyanates into epidermis where they can form stable immunogenic complexes with lysine-containing proteins.
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22
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Sanderson PN, Simpson W, Cubberley R, Aleksic M, Gutsell S, Russell PJ. Mechanistic understanding of molecular initiating events (MIEs) using NMR spectroscopy. Toxicol Res (Camb) 2015; 5:34-44. [PMID: 30090324 DOI: 10.1039/c5tx00246j] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2015] [Accepted: 09/11/2015] [Indexed: 11/21/2022] Open
Abstract
Toxicological risk assessments in the 21st century are increasingly being driven by the Adverse Outcome Pathways (AOP) conceptual framework in which the Molecular Initiating Event (MIE) is of fundamental importance to pathway progression. For those MIEs that involve covalent chemical reactions, such as protein haptenation, determination of relative rates and mechanisms of reactions is a prerequisite for their understanding. The utility of NMR spectroscopy as an experimental technique for effectively providing reaction rate and mechanistic information for early assessment of likely MIE(s) has been demonstrated. To demonstrate the concept, model systems exemplifying common chemical reactions involved in the covalent modification of proteins were utilized; these involved chemical reactions of electrophilic species (representing different mechanistic classes) with simple amine and thiol nucleophiles acting as surrogates for the reactive groups of lysine and cysteine protein side chains respectively. Such molecular interactions are recognized as critical mechanisms in a variety of chemical and drug toxicities, including respiratory and skin sensitization and liver toxicity as well as being the key mechanism of action for a number of therapeutic agents.
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Affiliation(s)
- Paul N Sanderson
- Unilever Safety & Environmental Assurance Centre , Colworth Science Park , Sharnbrook , Bedford , MK44 1LQ , UK .
| | - Wendy Simpson
- Unilever Safety & Environmental Assurance Centre , Colworth Science Park , Sharnbrook , Bedford , MK44 1LQ , UK .
| | - Richard Cubberley
- Unilever Safety & Environmental Assurance Centre , Colworth Science Park , Sharnbrook , Bedford , MK44 1LQ , UK .
| | - Maja Aleksic
- Unilever Safety & Environmental Assurance Centre , Colworth Science Park , Sharnbrook , Bedford , MK44 1LQ , UK .
| | - Stephen Gutsell
- Unilever Safety & Environmental Assurance Centre , Colworth Science Park , Sharnbrook , Bedford , MK44 1LQ , UK .
| | - Paul J Russell
- Unilever Safety & Environmental Assurance Centre , Colworth Science Park , Sharnbrook , Bedford , MK44 1LQ , UK .
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