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Crudo F, Dellafiora L, Hong C, Burger L, Jobst M, Del Favero G, Marko D. Combined in vitro and in silico mechanistic approach to explore the potential of Alternaria mycotoxins alternariol and altertoxin II to hamper γH2AX formation in DNA damage signaling pathways. Toxicol Lett 2024; 394:1-10. [PMID: 38403206 DOI: 10.1016/j.toxlet.2024.02.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2023] [Revised: 02/06/2024] [Accepted: 02/21/2024] [Indexed: 02/27/2024]
Abstract
Risk assessment of food and environmental contaminants is faced by substantial data gaps and novel strategies are needed to support science-based regulatory actions. The Alternaria mycotoxins alternariol (AOH) and altertoxin II (ATXII) have garnered attention for their possible genotoxic effects. Nevertheless, data currently available are rather scattered, hindering a comprehensive hazard characterization. This study combined in vitro/in silico approaches to elucidate the potential of AOH and ATXII to induce double-strand breaks (DSBs) in HepG2 cells. Furthermore, it examines the impact of co-exposure to AOH and the DSB-inducing drug doxorubicin (Doxo) on γH2AX expression. AOH slightly increased γH2AX expression, whereas ATXII did not elicit this response. Interestingly, AOH suppressed Doxo-induced γH2AX expression, despite evidence of increased DNA damage in the comet assay. Building on these observations, AOH was postulated to inhibit γH2AX-forming kinases. Along this line, in silico analysis supported AOH potential interaction with the ATP-binding sites of these kinases and immunofluorescence experiments showed decreased intracellular phosphorylation events. Similarly, in silico results suggested that ATXII might also interact with these kinases. This study emphasizes the importance of understanding the implications of AOH-induced γH2AX expression inhibition on DNA repair processes and underscores the need for caution when interpreting γH2AX assay results.
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Affiliation(s)
- Francesco Crudo
- Department of Food Chemistry and Toxicology, Faculty of Chemistry, University of Vienna, Währinger Str. 38, Vienna 1090, Austria
| | - Luca Dellafiora
- Department of Food and Drug, University of Parma, Area Parco delle Scienze 27/A, Parma 43124, Italy
| | - Chenyifan Hong
- Department of Food Chemistry and Toxicology, Faculty of Chemistry, University of Vienna, Währinger Str. 38, Vienna 1090, Austria
| | - Lena Burger
- Department of Food Chemistry and Toxicology, Faculty of Chemistry, University of Vienna, Währinger Str. 38, Vienna 1090, Austria
| | - Maximilian Jobst
- Department of Food Chemistry and Toxicology, Faculty of Chemistry, University of Vienna, Währinger Str. 38, Vienna 1090, Austria; Core Facility Multimodal Imaging, Faculty of Chemistry, University of Vienna, Währinger Str. 42, Vienna 1090, Austria; University of Vienna, Vienna Doctoral School in Chemistry (DoSChem), Währinger Str. 42, Vienna 1090, Austria
| | - Giorgia Del Favero
- Department of Food Chemistry and Toxicology, Faculty of Chemistry, University of Vienna, Währinger Str. 38, Vienna 1090, Austria; Core Facility Multimodal Imaging, Faculty of Chemistry, University of Vienna, Währinger Str. 42, Vienna 1090, Austria
| | - Doris Marko
- Department of Food Chemistry and Toxicology, Faculty of Chemistry, University of Vienna, Währinger Str. 38, Vienna 1090, Austria; Core Facility Multimodal Imaging, Faculty of Chemistry, University of Vienna, Währinger Str. 42, Vienna 1090, Austria.
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Louro H, Vettorazzi A, López de Cerain A, Spyropoulou A, Solhaug A, Straumfors A, Behr AC, Mertens B, Žegura B, Fæste CK, Ndiaye D, Spilioti E, Varga E, Dubreil E, Borsos E, Crudo F, Eriksen GS, Snapkow I, Henri J, Sanders J, Machera K, Gaté L, Le Hegarat L, Novak M, Smith NM, Krapf S, Hager S, Fessard V, Kohl Y, Silva MJ, Dirven H, Dietrich J, Marko D. Hazard characterization of Alternaria toxins to identify data gaps and improve risk assessment for human health. Arch Toxicol 2024; 98:425-469. [PMID: 38147116 PMCID: PMC10794282 DOI: 10.1007/s00204-023-03636-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2023] [Accepted: 11/09/2023] [Indexed: 12/27/2023]
Abstract
Fungi of the genus Alternaria are ubiquitous plant pathogens and saprophytes which are able to grow under varying temperature and moisture conditions as well as on a large range of substrates. A spectrum of structurally diverse secondary metabolites with toxic potential has been identified, but occurrence and relative proportion of the different metabolites in complex mixtures depend on strain, substrate, and growth conditions. This review compiles the available knowledge on hazard identification and characterization of Alternaria toxins. Alternariol (AOH), its monomethylether AME and the perylene quinones altertoxin I (ATX-I), ATX-II, ATX-III, alterperylenol (ALP), and stemphyltoxin III (STTX-III) showed in vitro genotoxic and mutagenic properties. Of all identified Alternaria toxins, the epoxide-bearing analogs ATX-II, ATX-III, and STTX-III show the highest cytotoxic, genotoxic, and mutagenic potential in vitro. Under hormone-sensitive conditions, AOH and AME act as moderate xenoestrogens, but in silico modeling predicts further Alternaria toxins as potential estrogenic factors. Recent studies indicate also an immunosuppressive role of AOH and ATX-II; however, no data are available for the majority of Alternaria toxins. Overall, hazard characterization of Alternaria toxins focused, so far, primarily on the commercially available dibenzo-α-pyrones AOH and AME and tenuazonic acid (TeA). Limited data sets are available for altersetin (ALS), altenuene (ALT), and tentoxin (TEN). The occurrence and toxicological relevance of perylene quinone-based Alternaria toxins still remain to be fully elucidated. We identified data gaps on hazard identification and characterization crucial to improve risk assessment of Alternaria mycotoxins for consumers and occupationally exposed workers.
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Affiliation(s)
- Henriqueta Louro
- Department of Human Genetics, National Institute of Health Dr. Ricardo Jorge (INSA) and Centre for Toxicogenomics and Human Health (ToxOmics), NOVA Medical School, Universidade Nova de Lisboa, Av. Padre Cruz, 1649-016, Lisbon, Portugal
| | - Ariane Vettorazzi
- MITOX Research Group, Department of Pharmaceutical Sciences, Faculty of Pharmacy and Nutrition, UNAV-University of Navarra, Pamplona, Spain
| | - Adela López de Cerain
- MITOX Research Group, Department of Pharmaceutical Sciences, Faculty of Pharmacy and Nutrition, UNAV-University of Navarra, Pamplona, Spain
| | - Anastasia Spyropoulou
- Laboratory of Toxicological Control of Pesticides, Scientific Directorate of Pesticides' Control and Phytopharmacy, Benaki Phytopathological Institute, 145 61, Attica, Greece
| | - Anita Solhaug
- Norwegian Veterinary Institute, PO Box 64, 1431, Ås, Norway
| | | | - Anne-Cathrin Behr
- Department Food Safety, BfR, German Federal Institute for Risk Assessment, Max-Dohrnstraße 8-10, 10589, Berlin, Germany
| | - Birgit Mertens
- Department of Chemical and Physical Health Risks, Sciensano, Brussels, Belgium
| | - Bojana Žegura
- Department of Genetic Toxicology and Cancer Biology, National Institute of Biology, Večna Pot 111, 1000, Ljubljana, Slovenia
| | | | - Dieynaba Ndiaye
- INRS, Institut National de Recherche et de Sécurité pour la Prévention des accidents du travail et des maladies professionnelles, Rue du Morvan, CS 60027, 54519, Vandœuvre Lès Nancy Cedex, France
| | - Eliana Spilioti
- Laboratory of Toxicological Control of Pesticides, Scientific Directorate of Pesticides' Control and Phytopharmacy, Benaki Phytopathological Institute, 145 61, Attica, Greece
| | - Elisabeth Varga
- Department of Food Chemistry and Toxicology, Faculty of Chemistry, University of Vienna, Vienna, Austria
- Food Hygiene and Technology, University of Veterinary Medicine, Vienna, Veterinärplatz 1, 1210, Vienna, Austria
| | - Estelle Dubreil
- Toxicology of Contaminants Unit, Fougères Laboratory, French Agency for Food, Environmental and Occupational Health and Safety, 10 B rue Claude Bourgelat, 35306, Fougères, France
| | - Eszter Borsos
- Food Hygiene and Technology, University of Veterinary Medicine, Vienna, Veterinärplatz 1, 1210, Vienna, Austria
| | - Francesco Crudo
- Food Hygiene and Technology, University of Veterinary Medicine, Vienna, Veterinärplatz 1, 1210, Vienna, Austria
| | | | - Igor Snapkow
- Department of Chemical Toxicology, Norwegian Institute of Public Health, Lovisenberggate 8, 0456, Oslo, Norway
| | - Jérôme Henri
- Toxicology of Contaminants Unit, Fougères Laboratory, French Agency for Food, Environmental and Occupational Health and Safety, 10 B rue Claude Bourgelat, 35306, Fougères, France
| | - Julie Sanders
- Department of Chemical and Physical Health Risks, Sciensano, Brussels, Belgium
| | - Kyriaki Machera
- Laboratory of Toxicological Control of Pesticides, Scientific Directorate of Pesticides' Control and Phytopharmacy, Benaki Phytopathological Institute, 145 61, Attica, Greece
| | - Laurent Gaté
- INRS, Institut National de Recherche et de Sécurité pour la Prévention des accidents du travail et des maladies professionnelles, Rue du Morvan, CS 60027, 54519, Vandœuvre Lès Nancy Cedex, France
| | - Ludovic Le Hegarat
- Toxicology of Contaminants Unit, Fougères Laboratory, French Agency for Food, Environmental and Occupational Health and Safety, 10 B rue Claude Bourgelat, 35306, Fougères, France
| | - Matjaž Novak
- Department of Genetic Toxicology and Cancer Biology, National Institute of Biology, Večna Pot 111, 1000, Ljubljana, Slovenia
| | - Nicola M Smith
- Department of Chemical Toxicology, Norwegian Institute of Public Health, Lovisenberggate 8, 0456, Oslo, Norway
| | - Solveig Krapf
- Norwegian Veterinary Institute, PO Box 64, 1431, Ås, Norway
| | - Sonja Hager
- Department of Food Chemistry and Toxicology, Faculty of Chemistry, University of Vienna, Vienna, Austria
| | - Valérie Fessard
- Toxicology of Contaminants Unit, Fougères Laboratory, French Agency for Food, Environmental and Occupational Health and Safety, 10 B rue Claude Bourgelat, 35306, Fougères, France
| | - Yvonne Kohl
- Fraunhofer Institute for Biomedical Engineering IBMT, Joseph-Von-Fraunhofer-Weg 1, 66280, Sulzbach, Germany
| | - Maria João Silva
- Department of Human Genetics, National Institute of Health Dr. Ricardo Jorge (INSA) and Centre for Toxicogenomics and Human Health (ToxOmics), NOVA Medical School, Universidade Nova de Lisboa, Av. Padre Cruz, 1649-016, Lisbon, Portugal
| | - Hubert Dirven
- Department of Chemical Toxicology, Norwegian Institute of Public Health, Lovisenberggate 8, 0456, Oslo, Norway
| | - Jessica Dietrich
- Department Safety in the Food Chain, BfR, German Federal Institute for Risk Assessment, Max-Dohrn-Straße 8-10, 10589, Berlin, Germany
| | - Doris Marko
- Department of Food Chemistry and Toxicology, Faculty of Chemistry, University of Vienna, Vienna, Austria.
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Kiefer A, Arnholdt M, Grimm V, Geske L, Groß J, Vierengel N, Opatz T, Erkel G. Structure elucidation and biological activities of perylenequinones from an Alternaria species. Mycotoxin Res 2023:10.1007/s12550-023-00495-1. [PMID: 37351768 PMCID: PMC10393905 DOI: 10.1007/s12550-023-00495-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2023] [Revised: 06/09/2023] [Accepted: 06/11/2023] [Indexed: 06/24/2023]
Abstract
The KEAP1-Nrf2/ARE pathway is a pivotal cytoprotective regulator against oxidative stress which plays an important role in the development of many inflammatory diseases and cancer. Activation of the Nrf2 transcription factor by oxidative stress or electrophiles regulates antioxidant response element (ARE)-dependent transcription of antioxidative, detoxifying, and anti-inflammatory proteins. Therefore, modulators of the KEAP1-Nrf2/ARE pathway have received considerable interest as therapeutics to protect against diseases where oxidative stress constitutes the underlying pathophysiology. In a search for fungal secondary metabolites affecting the Nrf2/ARE-dependent expression of a luciferase reporter gene in BEAS-2B cells, three new perylenequinones, compounds 1, 2, and 3, together with altertoxin-I (ATX-I), were isolated from fermentations of an Alternaria species. The structures of the compounds were elucidated by a combination of one- and two-dimensional NMR spectroscopy and mass spectrometry. Compound 1 and ATX-I exhibited strong cytotoxic effects with LC50-values of 3.8 µM and 6.43 µM, respectively, whereas compound 3 showed no cytotoxic effects up to 100 µM on BEAS-2B cells. ATX-I induced ARE-dependent luciferase expression approximately fivefold and compound 1 approximately 2.6-fold at a concentration of 3 µM in transiently transfected BEAS-2B cells. In addition, compound 1 and ATX-I exhibited strong oxidative effects, whereas compound 3 did not show significant oxidative properties. For compound 1 and ATX-I, a strong upregulation of heme oxygenase-1 could be observed on mRNA and protein level in treated BEAS-2B cells. Moreover, compound 3 significantly decreased sod3 mRNA levels after induction of oxidative stress with benzoquinone.
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Affiliation(s)
- Anna Kiefer
- Molecular Biotechnology & Systems Biology, RPTU, Paul-Ehrlich-Straße 23, D-67663, Kaiserslautern, Germany
| | - Marcel Arnholdt
- Molecular Biotechnology & Systems Biology, RPTU, Paul-Ehrlich-Straße 23, D-67663, Kaiserslautern, Germany
| | - Viktoria Grimm
- Molecular Biotechnology & Systems Biology, RPTU, Paul-Ehrlich-Straße 23, D-67663, Kaiserslautern, Germany
| | - Leander Geske
- Department of Chemistry, Johannes Gutenberg-University, Duesbergweg 10-14, D-55128, Mainz, Germany
| | - Jonathan Groß
- Department of Chemistry, Johannes Gutenberg-University, Duesbergweg 10-14, D-55128, Mainz, Germany
| | - Nina Vierengel
- Department of Chemistry, Johannes Gutenberg-University, Duesbergweg 10-14, D-55128, Mainz, Germany
| | - Till Opatz
- Department of Chemistry, Johannes Gutenberg-University, Duesbergweg 10-14, D-55128, Mainz, Germany.
| | - Gerhard Erkel
- Molecular Biotechnology & Systems Biology, RPTU, Paul-Ehrlich-Straße 23, D-67663, Kaiserslautern, Germany.
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Aichinger G, Pahlke G, Puntscher H, Groestlinger J, Grabher S, Braun D, Tillmann K, Plasenzotti R, Del Favero G, Warth B, Höger H, Marko D. Markers for DNA damage are induced in the rat colon by the Alternaria toxin altertoxin-II, but not a complex extract of cultured Alternaria alternata. FRONTIERS IN TOXICOLOGY 2022; 4:977147. [PMID: 36353200 PMCID: PMC9638006 DOI: 10.3389/ftox.2022.977147] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2022] [Accepted: 10/12/2022] [Indexed: 01/19/2024] Open
Abstract
Mycotoxins produced by Alternaria spp. act genotoxic in cell-based studies, but data on their toxicity in vivo is scarce and urgently required for risk assessment. Thus, male Sprague-Dawley rats received single doses of a complex Alternaria toxin extract (CE; 50 mg/kg bw), altertoxin II (ATX-II; 0.21 mg/kg bw) or vehicle by gavage, one of the most genotoxic metabolites in vitro and were sacrificed after 3 or 24 h, respectively. Using SDS-PAGE/Western Blot, a significant increase of histone 2a.X phosphorylation and depletion of the native protein was observed for rats that were exposed to ATX-II for 24 h. Applying RT-PCR array technology we identified genes of interest for qRT-PCR testing, which in turn confirmed an induction of Rnf8 transcription in the colon of rats treated with ATX-II for 3 h and CE for 24 h. A decrease of Cdkn1a transcription was observed in rats exposed to ATX-II for 24 h, possibly indicating tissue repair after chemical injury. In contrast to the observed response in the colon, no markers for genotoxicity were induced in the liver of treated animals. We hereby provide the first report of ATX-II as a genotoxicant in vivo. Deviating results for similar concentrations of ATX-II in a natural Alternaria toxin mixture argue for substantial mixture effects.
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Affiliation(s)
- Georg Aichinger
- Department of Food Chemistry and Toxicology, Faculty of Chemistry, University of Vienna, Vienna, Austria
- Laboratory of Toxicology, Department of Health Science and Technology, ETH Zurich, Switzerland
| | - Gudrun Pahlke
- Department of Food Chemistry and Toxicology, Faculty of Chemistry, University of Vienna, Vienna, Austria
| | - Hannes Puntscher
- Department of Food Chemistry and Toxicology, Faculty of Chemistry, University of Vienna, Vienna, Austria
| | - Julia Groestlinger
- Department of Food Chemistry and Toxicology, Faculty of Chemistry, University of Vienna, Vienna, Austria
| | - Stephanie Grabher
- Department of Food Chemistry and Toxicology, Faculty of Chemistry, University of Vienna, Vienna, Austria
| | - Dominik Braun
- Department of Food Chemistry and Toxicology, Faculty of Chemistry, University of Vienna, Vienna, Austria
| | - Katharina Tillmann
- Center for Biomedical Research, Medical University of Vienna, Vienna, Austria
| | - Roberto Plasenzotti
- Center for Biomedical Research, Medical University of Vienna, Vienna, Austria
| | - Giorgia Del Favero
- Department of Food Chemistry and Toxicology, Faculty of Chemistry, University of Vienna, Vienna, Austria
- Core Facility Multimodal Imaging, Faculty of Chemistry, University of Vienna, Vienna, Austria
| | - Benedikt Warth
- Department of Food Chemistry and Toxicology, Faculty of Chemistry, University of Vienna, Vienna, Austria
| | - Harald Höger
- Center for Biomedical Research, Medical University of Vienna, Vienna, Austria
| | - Doris Marko
- Department of Food Chemistry and Toxicology, Faculty of Chemistry, University of Vienna, Vienna, Austria
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Aichinger G, Del Favero G, Warth B, Marko D. Alternaria toxins-Still emerging? Compr Rev Food Sci Food Saf 2021; 20:4390-4406. [PMID: 34323368 DOI: 10.1111/1541-4337.12803] [Citation(s) in RCA: 37] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2020] [Revised: 06/18/2021] [Accepted: 06/19/2021] [Indexed: 12/13/2022]
Abstract
Alternaria molds are known to cause the contamination of food with their secondary metabolites, a chemically very heterogeneous group of compounds. Yet, after decades of research on the occurrence and the toxicity of Alternaria toxins in academia, no regulation has been implemented yet, thus leaving these potential food contaminants in the status of so-called "emerging mycotoxins". However, research on this topic has been far from static, leading to the European Food Safety Authority repeatedly calling for more data on the occurrence and toxicity of genotoxic metabolites such as alternariol (AOH) and its monomethyl ether (AME). To give an overview on recent developments in the field, this comprehensive review summarizes published data and addresses current challenges arising from the chemical complexity of Alternaria's metabolome, mixture effects and the emergence of novel biological targets like cell membranes or the interaction with different receptors. Besides toxicodynamics, we review recent research on toxicokinetics, including the first in vivo studies which incorporated the rarely investigated-but highly genotoxic-perylene quinones. Furthermore, a particular focus lies on the advances of liquid chromatography/tandem mass spectrometry (LC-MS/MS)-based analytical tools for determining a broader spectrum of Alternaria toxins including modified/masked forms and assessing exposure via human biomonitoring (HBM).
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Affiliation(s)
- Georg Aichinger
- Department of Food Chemistry and Toxicology, Faculty of Chemistry, University of Vienna, Wien, Austria
| | - Giorgia Del Favero
- Department of Food Chemistry and Toxicology, Faculty of Chemistry, University of Vienna, Wien, Austria
| | - Benedikt Warth
- Department of Food Chemistry and Toxicology, Faculty of Chemistry, University of Vienna, Wien, Austria
| | - Doris Marko
- Department of Food Chemistry and Toxicology, Faculty of Chemistry, University of Vienna, Wien, Austria
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