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Plata-Calzado C, Diez-Quijada L, Medrano-Padial C, Prieto AI, Cameán AM, Jos A. In Vitro Mutagenic and Genotoxic Assessment of Anatoxin-a Alone and in Combination with Cylindrospermopsin. Toxins (Basel) 2023; 15:458. [PMID: 37505727 PMCID: PMC10467140 DOI: 10.3390/toxins15070458] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2023] [Revised: 07/05/2023] [Accepted: 07/11/2023] [Indexed: 07/29/2023] Open
Abstract
Anatoxin-a (ATX-a) is a cyanobacterial toxin whose occurrence has been reported worldwide and has attracted increasing scientific interest due to its toxicity. Moreover, in nature, ATX-a usually appears together with other cyanotoxins, such as cylindrospermopsin (CYN), so possible interaction phenomena could happen and should be considered for risk assessment purposes. For this reason, the aim of this work was to explore the potential mutagenicity and genotoxicity of pure ATX-a and an ATX-a/CYN mixture using a battery of in vitro assays, including the bacterial reverse-mutation assay in Salmonella typhimurium (OECD 471) and the micronucleus test (MN) (OECD 487) on L5178Y Tk+/- cells. The results showed that ATX-a was not mutagenic either alone or in combination with CYN under the conditions tested. Nevertheless, genotoxic effects were observed for both ATX-a and its mixture with CYN following the in vitro MN assay. The genotoxicity exhibited by ATX-a was only observed in the absence of S9 mix, whereas in the cyanotoxin mixture the concentration-dependent genotoxicity of ATX-a/CYN in vitro was observed only in the presence of S9. Thus, the toxicity induced by cyanotoxin mixtures may vary from that produced by toxins alone, and consequently more studies are necessary in order to perform more realistic risk assessments.
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Affiliation(s)
| | | | | | - Ana I. Prieto
- Area of Toxicology, Faculty of Pharmacy, Universidad de Sevilla, Profesor García González 2, 41012 Seville, Spain; (C.P.-C.); (L.D.-Q.); (C.M.-P.); (A.M.C.)
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Toxic Effects Produced by Anatoxin-a under Laboratory Conditions: A Review. Toxins (Basel) 2022; 14:toxins14120861. [PMID: 36548758 PMCID: PMC9784168 DOI: 10.3390/toxins14120861] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2022] [Revised: 11/18/2022] [Accepted: 12/06/2022] [Indexed: 12/13/2022] Open
Abstract
The presence of cyanotoxins and its bioaccumulation in the food chain is an increasingly common problem worldwide. Despite the toxic effects produced by Anatoxin-a (ATX-a), this neurotoxin has been less studied compared to microcystins (MCs) and cylindrospermopsin (CYN). Studies conducted under laboratory conditions are of particular interest because these provide information which are directly related to the effects produced by the toxin. Currently, the World Health Organization (WHO) considers the ATX-a toxicological database inadequate to support the publication of a formal guideline reference value. Therefore, the aim of the present work is to compile all of the in vitro and in vivo toxicological studies performed so far and to identify potential data gaps. Results show that the number of reports is increasing in recent years. However, more in vitro studies are needed, mainly in standardized neuronal cell lines. Regarding in vivo studies, very few of them reflect conditions occurring in nature and further studies with longer periods of oral exposure would be of interest. Moreover, additional toxicological aspects of great interest such as mutagenicity, genotoxicity, immunotoxicity and alteration of hormonal balance need to be studied in depth.
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Ahari H, Nowruzi B, Anvar AA, Porzani SJ. The Toxicity Testing of Cyanobacterial Toxins In Vivo and In Vitro by Mouse Bioassay: A Review. Mini Rev Med Chem 2021; 22:1131-1151. [PMID: 34720080 DOI: 10.2174/1389557521666211101162030] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2020] [Revised: 07/26/2021] [Accepted: 08/21/2021] [Indexed: 11/22/2022]
Abstract
Different biological methods based on bioactivity are available to detect cyanotoxins, including neurotoxicity, immunological interactions, hepatotoxicity, cytotoxicity, and enzymatic activity. The mouse bioassay is the first test employed in laboratory cultures, cell extracts, and water bloom materials to detect toxins. It is also used as a traditional method to estimate the LD50. Concerning the ease of access and low cost, it is the most common method for this purpose. In this method, a sample is injected intraperitoneally into adult mice, and accordingly, they are assayed and monitored for about 24 hours for toxic symptoms. The toxin can be detected using this method from minutes to a few hours; its type, e.g., hepatotoxin, neurotoxin, etc., can also be determined. However, this method is nonspecific, fails to detect low amounts, and cannot distinguish between homologues. Although the mouse bioassay is gradually replaced with new chemical and immunological methods, it is still the main technique to detect the bioactivity and efficacy of cyanotoxins using LD50 determined based on the survival time of animals exposed to the toxin. In addition, some countries oppose animal use in toxicity studies. However, high cost, ethical considerations, low-sensitivity, non-specificity, and prolonged processes persuade researchers to employ chemical and functional analysis techniques. The qualitative and quantitative analyses, as well as high specificity and sensitivity, are among the advantages of cytotoxicity tests to investigate cyanotoxins. The present study aimed at reviewing the results obtained from in-vitro and in-vivo investigations of the mouse bioassay to detect cyanotoxins, including microcystins, cylindrospermopsin, saxitoxins, etc.
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Affiliation(s)
- Hamed Ahari
- Department of Food Science and Technology, Science and Research Branch, Islamic Azad University, Tehran. Iran
| | - Bahareh Nowruzi
- Department of Biology, Science and Research Branch, Islamic Azad University, Tehran. Iran
| | - Amir Ali Anvar
- Department of Food Hygiene, Science and Research Branch, Islamic Azad University, Tehran. Iran
| | - Samaneh Jafari Porzani
- Department of Biology, Science and Research Branch, Islamic Azad University, Tehran. Iran
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Cytotoxic and Genotoxic Effects of Cyanobacterial and Algal Extracts-Microcystin and Retinoic Acid Content. Toxins (Basel) 2021; 13:toxins13020107. [PMID: 33540511 PMCID: PMC7912913 DOI: 10.3390/toxins13020107] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2021] [Revised: 01/22/2021] [Accepted: 01/26/2021] [Indexed: 12/11/2022] Open
Abstract
In the last decade, it has become evident that complex mixtures of cyanobacterial bioactive substances, simultaneously present in blooms, often exert adverse effects that are different from those of pure cyanotoxins, and awareness has been raised on the importance of studying complex mixtures and chemical interactions. We aimed to investigate cytotoxic and genotoxic effects of complex extracts from laboratory cultures of cyanobacterial species from different orders (Cylindrospermopsis raciborskii, Aphanizomenon gracile, Microcystis aeruginosa, M. viridis, M. ichtyoblabe, Planktothrix agardhii, Limnothrix redekei) and algae (Desmodesmus quadricauda), and examine possible relationships between the observed effects and toxin and retinoic acid (RA) content in the extracts. The cytotoxic and genotoxic effects of the extracts were studied in the human hepatocellular carcinoma HepG2 cell line, using the MTT assay, and the comet and cytokinesis-block micronucleus (cytome) assays, respectively. Liquid chromatography electrospray ionization mass spectrometry (LC/ESI-MS) was used to detect toxins (microcystins (MC-LR, MC-RR, MC-YR) and cylindrospermopsin) and RAs (ATRA and 9cis-RA) in the extracts. Six out of eight extracts were cytotoxic (0.04–2 mgDM/mL), and five induced DNA strand breaks at non-cytotoxic concentrations (0.2–2 mgDM/mL). The extracts with genotoxic activity also had the highest content of RAs and there was a linear association between RA content and genotoxicity, indicating their possible involvement; however further research is needed to identify and confirm the compounds involved and to elucidate possible genotoxic effects of RAs.
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Porzani SJ, Lima ST, Metcalf JS, Nowruzi B. In Vivo and In Vitro Toxicity Testing of Cyanobacterial Toxins: A Mini-Review. REVIEWS OF ENVIRONMENTAL CONTAMINATION AND TOXICOLOGY 2021; 258:109-150. [PMID: 34622370 DOI: 10.1007/398_2021_74] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Harmful cyanobacterial blooms are increasing and becoming a worldwide concern as many bloom-forming cyanobacterial species can produce toxic metabolites named cyanotoxins. These include microcystins, saxitoxins, anatoxins, nodularins, and cylindrospermopsins, which can adversely affect humans, animals, and the environment. Different methods to assess these classes of compounds in vitro and in vivo include biological, biochemical, molecular, and physicochemical techniques. Furthermore, toxic effects not attributable to known cyanotoxins can be observed when assessing bloom material. In order to determine exposures to cyanotoxins and to monitor compliance with drinking and bathing water guidelines, it is necessary to have reliable and effective methods for the analysis of these compounds. Many relatively simple low-cost methods can be employed to rapidly evaluate the potential hazard. The main objective of this mini-review is to describe the assessment of toxic cyanobacterial samples using in vitro and in vivo bioassays. Newly emerging cyanotoxins, the toxicity of analogs, or the interaction of cyanobacteria and cyanotoxins with other toxicants, among others, still requires bioassay assessment. This review focuses on some biological and biochemical assays (MTT assay, Immunohistochemistry, Micronucleus Assay, Artemia salina assay, Daphnia magna test, Radionuclide recovery, Neutral red cytotoxicity and Comet assay, Enzyme-Linked Immunosorbent Assay (ELISA), Annexin V-FITC assay and Protein Phosphatase Inhibition Assay (PPIA)) for the detection and measurement of cyanotoxins including microcystins, cylindrospermopsins, anatoxin-a, saxitoxins, and nodularins. Although most bioassay analyses often confirm the presence of cyanotoxins at low concentrations, such bioassays can be used to determine whether some strains or blooms of cyanobacteria may produce other, as yet unknown toxic metabolites. This review also aims to identify research needs and data gaps concerning the toxicity assessment of cyanobacteria.
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Affiliation(s)
- Samaneh J Porzani
- Department of Biology, Science and Research Branch, Islamic Azad University, Tehran, Iran
| | - Stella T Lima
- Center for Nuclear Energy in Agriculture, University of Sao Paulo, Piracicaba, Brazil
| | | | - Bahareh Nowruzi
- Department of Biology, Science and Research Branch, Islamic Azad University, Tehran, Iran.
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Schreidah CM, Ratnayake K, Senarath K, Karunarathne A. Microcystins: Biogenesis, Toxicity, Analysis, and Control. Chem Res Toxicol 2020; 33:2225-2246. [PMID: 32614166 DOI: 10.1021/acs.chemrestox.0c00164] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Microcystins are cyclic peptide toxins formed by cyanobacteria. These toxins are recognized for their association with algal blooms, posing a significant threat to ecosystems and drinking water quality. Due to the growing environmental concerns they raise, a comprehensive review on microcystins' genesis, toxicity, and analytical methods for their quantitative determination is outlined. Genes, including the mcyABC cluster, regulate microcystin biogenesis. Bioanalytical experiments have identified key environmental factors, such as temperature and nitrogen availability, that promote microcystin production. Microcystin toxicity is explored based on its modulatory effects on protein phosphatases 1 and 2A in specific tissues and organs. Additionally, biochemical mechanisms of chelation, transportation, resultant oxidative stress, and tumor promotion abilities of microcystins are also discussed. Various analytical methods to separate, detect, and quantify microcystins, including the quantitative real-time polymerase chain reaction, enzyme-linked immunosorbent assay, nuclear magnetic resonance spectroscopy, and chromatographic platforms-linked tandem mass spectrometry (LC-MS) for unequivocal structural identification, are also reviewed. Since control of microcystins in water is of great necessity, both water treatment and mechanisms of abiotic transformation and microbial degradation are also discussed.
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Affiliation(s)
- Celine M Schreidah
- Vagelos College of Physicians and Surgeons, Columbia University, New York, New York 10032, United States
- Department of Chemistry and Biochemistry, University of Toledo, Toledo, Ohio 43606, United States
| | - Kasun Ratnayake
- Department of Chemistry and Biochemistry, University of Toledo, Toledo, Ohio 43606, United States
| | - Kanishka Senarath
- Department of Chemistry and Biochemistry, University of Toledo, Toledo, Ohio 43606, United States
- Department of Chemistry, University of Colombo, Colombo 00300, Sri Lanka
| | - Ajith Karunarathne
- Department of Chemistry and Biochemistry, University of Toledo, Toledo, Ohio 43606, United States
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Díez-Quijada L, Medrano-Padial C, Llana-Ruiz-Cabello M, Cătunescu GM, Moyano R, Risalde MA, Cameán AM, Jos Á. Cylindrospermopsin-Microcystin-LR Combinations May Induce Genotoxic and Histopathological Damage in Rats. Toxins (Basel) 2020; 12:E348. [PMID: 32466519 PMCID: PMC7354441 DOI: 10.3390/toxins12060348] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2020] [Revised: 05/21/2020] [Accepted: 05/23/2020] [Indexed: 12/28/2022] Open
Abstract
Cylindrospermopsin (CYN) and microcystins (MC) are cyanotoxins that can occur simultaneously in contaminated water and food. CYN/MC-LR mixtures previously investigated in vitro showed an induction of micronucleus (MN) formation only in the presence of the metabolic fraction S9. When this is the case, the European Food Safety Authority recommends a follow up to in vivo testing. Thus, rats were orally exposed to 7.5 + 75, 23.7 + 237, and 75 + 750 μg CYN/MC-LR/kg body weight (b.w.). The MN test in bone marrow was performed, and the standard and modified comet assays were carried out to measure DNA strand breaks or oxidative DNA damage in stomach, liver, and blood cells. The results revealed an increase in MN formation in bone marrow, at all the assayed doses. However, no DNA strand breaks nor oxidative DNA damage were induced, as shown in the comet assays. The histopathological study indicated alterations only in the highest dose group. Liver was the target organ showing fatty degeneration and necrotic hepatocytes in centrilobular areas, as well as a light mononuclear inflammatory periportal infiltrate. Additionally, the stomach had flaking epithelium and mild necrosis of epithelial cells. Therefore, the combined exposure to cyanotoxins may induce genotoxic and histopathological damage in vivo.
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Affiliation(s)
- Leticia Díez-Quijada
- Area of Toxicology, Faculty of Pharmacy, University of Sevilla, Profesor García González n2, 41012 Sevilla, Spain; (L.D.-Q.); (C.M.-P.); (M.L.-R.-C.); (Á.J.)
| | - Concepción Medrano-Padial
- Area of Toxicology, Faculty of Pharmacy, University of Sevilla, Profesor García González n2, 41012 Sevilla, Spain; (L.D.-Q.); (C.M.-P.); (M.L.-R.-C.); (Á.J.)
| | - María Llana-Ruiz-Cabello
- Area of Toxicology, Faculty of Pharmacy, University of Sevilla, Profesor García González n2, 41012 Sevilla, Spain; (L.D.-Q.); (C.M.-P.); (M.L.-R.-C.); (Á.J.)
| | - Giorgiana M. Cătunescu
- University of Agricultural Sciences and Veterinary Medicine Cluj-Napoca, Calea Mănăștur 3-5, 400372 Cluj-Napoca, Romania;
| | - Rosario Moyano
- Department of Pharmacology, Toxicology and Legal and Forensic Medicine, Faculty of Veterinary Medicine, University of Córdoba, Campus de Rabanales, 14014 Córdoba, Spain;
| | - Maria A. Risalde
- Animal Pathology Department. Faculty of Veterinary Medicine, University of Córdoba, Campus Universitario de Rabanales s/n, 14014 Cordoba, Spain;
- Instituto Maimonides de Investigación Biomédica de Córdoba (IMIBIC)-Hospital Universitario Reina Sofía de Córdoba-Universidad de Córdoba, Avenida Menendez Pidal s/n, 14006 Cordoba, Spain
| | - Ana M. Cameán
- Area of Toxicology, Faculty of Pharmacy, University of Sevilla, Profesor García González n2, 41012 Sevilla, Spain; (L.D.-Q.); (C.M.-P.); (M.L.-R.-C.); (Á.J.)
| | - Ángeles Jos
- Area of Toxicology, Faculty of Pharmacy, University of Sevilla, Profesor García González n2, 41012 Sevilla, Spain; (L.D.-Q.); (C.M.-P.); (M.L.-R.-C.); (Á.J.)
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Díez-Quijada L, Prieto AI, Puerto M, Jos Á, Cameán AM. In Vitro Mutagenic and Genotoxic Assessment of a Mixture of the Cyanotoxins Microcystin-LR and Cylindrospermopsin. Toxins (Basel) 2019; 11:E318. [PMID: 31167415 PMCID: PMC6628426 DOI: 10.3390/toxins11060318] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2019] [Revised: 05/29/2019] [Accepted: 05/31/2019] [Indexed: 12/18/2022] Open
Abstract
The co-occurrence of various cyanobacterial toxins can potentially induce toxic effects different than those observed for single cyanotoxins, as interaction phenomena cannot be discarded. Moreover, mixtures are a more probable exposure scenario. However, toxicological information on the topic is still scarce. Taking into account the important role of mutagenicity and genotoxicity in the risk evaluation framework, the objective of this study was to assess the mutagenic and genotoxic potential of mixtures of two of the most relevant cyanotoxins, Microcystin-LR (MC-LR) and Cylindrospermopsin (CYN), using the battery of in vitro tests recommended by the European Food Safety Authority (EFSA) for food contaminants. Mixtures of 1:10 CYN/MC-LR (CYN concentration in the range 0.04-2.5 µg/mL) were used to perform the bacterial reverse-mutation assay (Ames test) in Salmonella typhimurium, the mammalian cell micronucleus (MN) test and the mouse lymphoma thymidine-kinase assay (MLA) on L5178YTk± cells, while Caco-2 cells were used for the standard and enzyme-modified comet assays. The exposure periods ranged between 4 and 72 h depending on the assay. The genotoxicity of the mixture was observed only in the MN test with S9 metabolic fraction, similar to the results previously reported for CYN individually. These results indicate that cyanobacterial mixtures require a specific (geno)toxicity evaluation as their effects cannot be extrapolated from those of the individual cyanotoxins.
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Affiliation(s)
- Leticia Díez-Quijada
- Area of Toxicology, Faculty of Pharmacy, University of Sevilla, C/Profesor García González 2, 41012 Sevilla, Spain.
| | - Ana I Prieto
- Area of Toxicology, Faculty of Pharmacy, University of Sevilla, C/Profesor García González 2, 41012 Sevilla, Spain.
| | - María Puerto
- Area of Toxicology, Faculty of Pharmacy, University of Sevilla, C/Profesor García González 2, 41012 Sevilla, Spain.
| | - Ángeles Jos
- Area of Toxicology, Faculty of Pharmacy, University of Sevilla, C/Profesor García González 2, 41012 Sevilla, Spain.
| | - Ana M Cameán
- Area of Toxicology, Faculty of Pharmacy, University of Sevilla, C/Profesor García González 2, 41012 Sevilla, Spain.
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Díez-Quijada L, Prieto AI, Guzmán-Guillén R, Jos A, Cameán AM. Occurrence and toxicity of microcystin congeners other than MC-LR and MC-RR: A review. Food Chem Toxicol 2018; 125:106-132. [PMID: 30597222 DOI: 10.1016/j.fct.2018.12.042] [Citation(s) in RCA: 88] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2018] [Revised: 11/29/2018] [Accepted: 12/25/2018] [Indexed: 12/11/2022]
Abstract
The occurrence of cyanobacterial toxins is being increasingly reported. This is a reason for concern as they can induce toxic effects both in humans and in the environment. Among them, microcystins (MCs) are the best described and most diverse group of cyanobacterial toxins, and MC-LR and MC-RR are the congeners most widely investigated. However, the number of MC variants has also increased in recent years. Some of these minority variants have been shown to have a different toxicokinetic and toxicodynamic profile, but research focused on them is still limited. Moreover, in some water bodies these minority variants can be the predominant toxins. Nonetheless, MC-LR is the only one used for risk evaluation purposes at present. In order to contribute to more realistic risk assessments in the future, the aim of this review was to compile the available information in the scientific literature regarding the occurrence and concentration of minority MCs in water and food samples, and their toxic effects. The data retrieved demonstrate the congener-specific toxicity of MCs, as well as many data gaps in relation to analytical or mechanistic aspects, among others. Therefore, further research is needed to improve the toxicological characterization of these toxins and the exposure scenarios.
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Affiliation(s)
- Leticia Díez-Quijada
- Area of Toxicology, Faculty of Pharmacy, Universidad de Sevilla, C/Profesor García González 2, 41012, Seville, Spain
| | - Ana I Prieto
- Area of Toxicology, Faculty of Pharmacy, Universidad de Sevilla, C/Profesor García González 2, 41012, Seville, Spain
| | - Remedios Guzmán-Guillén
- Area of Toxicology, Faculty of Pharmacy, Universidad de Sevilla, C/Profesor García González 2, 41012, Seville, Spain
| | - Angeles Jos
- Area of Toxicology, Faculty of Pharmacy, Universidad de Sevilla, C/Profesor García González 2, 41012, Seville, Spain.
| | - Ana M Cameán
- Area of Toxicology, Faculty of Pharmacy, Universidad de Sevilla, C/Profesor García González 2, 41012, Seville, Spain
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Fonseca VB, Sopezki MDS, Yunes JS, Zanette J. Effect of a toxic Microcystis aeruginosa lysate on the mRNA expression of proto-oncogenes and tumor suppressor genes in zebrafish. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2018; 161:729-734. [PMID: 29957580 DOI: 10.1016/j.ecoenv.2018.06.007] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/08/2018] [Revised: 05/23/2018] [Accepted: 06/03/2018] [Indexed: 06/08/2023]
Abstract
Cyanobacterial blooms of Microcystis aeruginosa represent a significant risk to the environment and have become a worldwide concern. M. aeruginosa can produce the hepatotoxins microcystins (MCs) with potential for tumor promotion. The present study evaluated the time-dependent effects in the transcription of tumor-related genes in the zebrafish, Danio rerio, exposed to dilutions of a M. aeruginosa lysate containing 3.5 and 54.6 µg L-1 MCs. We used a cultured M. aeruginosa strain, RST 9501, which contains mainly the variant [D-Leu1] MC-LR and originated from the Patos Lagoon Estuary (RS, Brazil). The exposure caused short-term repression of tumor suppressor genes and long-term repression of proto-oncogenes. These responses were more evident for p53 that was repressed with exposure for 6, 24 and 96 h, and fosab and myca that were consistently repressed with exposure for 384 h, when fish were exposed to both M. aeruginosa lysate dilutions, compared to controls (p < 0.05). The suppressor genes, baxa and gadd45α, and the proto-oncogene, junba, were suppressed mainly at 96 h, where both dilutions of the lysate caused repression compared to controls (p < 0.05). The p53 gene was the only gene to be induced; this occurred in fish exposed to lysate containing 3.5 µg L-1 for 384 h. This is the first study to show that M. aeruginosa containing an environmentally relevant concentration of [D-Leu1] MC-LR could cause time-dependent repression of proto-oncogenes and tumor suppressor genes in fish. The results suggest that short-term repression of tumor suppressor genes could participate in the mechanism of tumor promotion caused by M. aeruginosa in fish.
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Affiliation(s)
- Viviane Barneche Fonseca
- Programa de Pós-Graduação em Ciências Fisiológicas, Instituto de Ciências Biológicas (ICB), Universidade Federal do Rio Grande (FURG), Rio Grande, RS 96203-900, Brazil
| | - Mauricio da Silva Sopezki
- Programa de Pós-Graduação em Ciências Fisiológicas, Instituto de Ciências Biológicas (ICB), Universidade Federal do Rio Grande (FURG), Rio Grande, RS 96203-900, Brazil
| | - João Sarkis Yunes
- Laboratório de Cianobactérias e Ficotoxinas, Instituto de Oceanografia (IO), Universidade Federal do Rio Grande (FURG), Rio Grande, RS 96203-900, Brazil
| | - Juliano Zanette
- Programa de Pós-Graduação em Ciências Fisiológicas, Instituto de Ciências Biológicas (ICB), Universidade Federal do Rio Grande (FURG), Rio Grande, RS 96203-900, Brazil.
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Hercog K, Maisanaba S, Filipič M, Jos Á, Cameán AM, Žegura B. Genotoxic potential of the binary mixture of cyanotoxins microcystin-LR and cylindrospermopsin. CHEMOSPHERE 2017; 189:319-329. [PMID: 28942258 DOI: 10.1016/j.chemosphere.2017.09.075] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/12/2017] [Revised: 09/09/2017] [Accepted: 09/15/2017] [Indexed: 06/07/2023]
Abstract
Increased eutrophication of water bodies promotes cyanobacterial blooming that is hazardous due to the production of various bioactive compounds. Microcystin-LR (MCLR) is among the most widespread cyanotoxins classified as possible human carcinogen, while cylindrospermopsin (CYN) has only recently been recognized as health concern. Both cyanotoxins are genotoxic; however, the mechanisms of their action differ. They are ubiquitously present in water environment and are often detected together. Therefore, we studied genotoxic potential of the binary mixture of these cyanotoxins. Human hepatoma cells (HepG2) were exposed to a single dose of MCLR (1 μg/mL), graded doses of CYN (0.01-0.5 μg/mL), and their combinations. Comet and Cytokinesis block micronucleus assays were used to detect induction of DNA strand breaks (sb) and genomic instability, respectively, along with the transcriptional analyses of the expression of selected genes involved in xenobiotic metabolism, immediate/early cell response and DNA-damage response. MCLR induced DNA sb that were only transiently present after 4 h exposure, whereas CYN, after 24 h exposure, induced DNA sb and genomic instability. The MCLR/CYN mixture induced DNA sb after 24 h exposure, but to lesser extent as CYN alone. On the other hand, induction of genomic instability by the MCLR/CYN mixture was comparable to that induced by CYN alone. In addition, patterns of changes in the expression of selected genes induced by the MCLR/CYN mixture were not significantly different from those induced by CYN alone. Our results indicate that CYN exerts higher genotoxic potential than MCLR and that genotoxic potential of the MCLR/CYN mixture is comparable to that of CYN alone.
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Affiliation(s)
- Klara Hercog
- Department of Genetic Toxicology and Cancer Biology, National Institute of Biology, Slovenia; Jozef Stefan International Postgraduate School, Ljubljana, Slovenia
| | - Sara Maisanaba
- Area of Toxicology, Department of Nutrition and Bromatology, Toxicology and Legal Medicine, Faculty of Pharmacy, University of Sevilla, Spain
| | - Metka Filipič
- Department of Genetic Toxicology and Cancer Biology, National Institute of Biology, Slovenia
| | - Ángeles Jos
- Area of Toxicology, Department of Nutrition and Bromatology, Toxicology and Legal Medicine, Faculty of Pharmacy, University of Sevilla, Spain
| | - Ana M Cameán
- Area of Toxicology, Department of Nutrition and Bromatology, Toxicology and Legal Medicine, Faculty of Pharmacy, University of Sevilla, Spain
| | - Bojana Žegura
- Department of Genetic Toxicology and Cancer Biology, National Institute of Biology, Slovenia.
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McLellan NL, Manderville RA. Toxic mechanisms of microcystins in mammals. Toxicol Res (Camb) 2017; 6:391-405. [PMID: 30090507 PMCID: PMC6060792 DOI: 10.1039/c7tx00043j] [Citation(s) in RCA: 104] [Impact Index Per Article: 14.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2017] [Accepted: 04/21/2017] [Indexed: 01/08/2023] Open
Abstract
Microcystins, such as microcystin-leucine arginine (MC-LR), are some of the most toxic and prevalent cyanotoxins produced by cyanobacteria in freshwater and saltwater algal blooms worldwide. Acute and chronic exposures to microcystins are primarily known to cause hepatotoxicity; cellular damage and genotoxicity within mammalian livers. However, in vivo studies indicate that similar damage may occur in other mammalian organs and tissues, such as the kidney, heart, reproductive systems, and lungs - particularly following chronic low-dose exposures. Mechanisms of toxicity of mycrocystins are reviewed herein; including cellular uptake, interaction with protein phosphatases PP1 and PP2A, cytoskeletal effects, formation of oxidative stress and induction of apoptosis. In general, the mode of action of toxicity by MCs in mammalian organs are similar to those that have been observed in liver tissues. A comprehensive understanding of the toxic mechanisms of microcystins in mammalian tissues and organs will assist in the development of risk assessment approaches to public health protection strategies and the development of robust drinking water policies.
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Affiliation(s)
- Nicole L McLellan
- School of Environmental Sciences , University of Guelph , Guelph , Ontario N1G 2W1 , Canada
| | - Richard A Manderville
- Department of Chemistry and Toxicology , University of Guelph , Guelph , Ontario N1G 2W1 , Canada . ; ; Tel: +1-519-824-4120, x53963
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13
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Qualitative analysis of the most toxic and abundant microcystin variants (LR, RR, and YR) by using LCMS–IT–TOF. J IND ENG CHEM 2015. [DOI: 10.1016/j.jiec.2015.04.018] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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14
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Han S, Zhou Q, Xu Y, Vanogtrop F, Guo Q, Liu G, Yan S. Valuable ingredients and feed toxicity evaluation of Microcystis aeruginosa acidolysis product in mice. Exp Biol Med (Maywood) 2015; 240:1333-9. [PMID: 25649189 DOI: 10.1177/1535370214563894] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2014] [Accepted: 10/28/2014] [Indexed: 11/16/2022] Open
Abstract
This research studied the extraction from Microcystis aeruginosa using hydrochloric acid method as a potentially valuable protein resource from eutrophic lakes. Amino acid composition, residual algal toxins, and heavy metals of the acidolysis product were studied. After 18 h of hydrochloric acid treatment, the product of M. aeruginosa contained 17 amino acids, 51.34% of total amino acid requirements, and 30.25% of the livestock and poultry essential amino acid (Eaa). The residual microcystin-LR (MC-LR) was 0.94 µg kg(-1), which was less than WHO drinking water limit of microcystins. The removal ratio of microcystins was higher than 99.99% during the process of hydrolysis. The concentration of heavy metals of the product was in compliance with feed standards. Furthermore, using Horn's method, Mouse Micronucleus Test and Sperm Shape Abnormality Test were conducted to study the forage safety of the product. Half lethal dose (LD50) of acidolysis product in mice was >9.09 g kg(-1) body weight, actually belonging to non-toxic grade. Every dose treatment did not significantly increase activities of alkaline phosphatase (ALP), lactate dehydrogenase (LDH), and γ-glutamyltransferase (γ-GT). The results of both micronucleus test and sperm shape abnormality test were negative, which suggested the product with no mutagenicity and sperm malformation effects. This study indicated that the acidolysis product of M. aeruginosa was safe to be used as a feed ingredient.
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Affiliation(s)
- Shiqun Han
- Institution of Agricultural Resource and Environmental Sciences, Jiangsu Academy of Agricultural Sciences, Nanjing, Jiangsu 210014, China
| | - Qing Zhou
- Institution of Agricultural Resource and Environmental Sciences, Jiangsu Academy of Agricultural Sciences, Nanjing, Jiangsu 210014, China
| | - Yudi Xu
- Institution of Agricultural Resource and Environmental Sciences, Jiangsu Academy of Agricultural Sciences, Nanjing, Jiangsu 210014, China
| | - Floris Vanogtrop
- Faculty of Agriculture and Environment, University of Sydney, Sydney 2006, Australia
| | - Qijin Guo
- Institution of Agricultural Resource and Environmental Sciences, Jiangsu Academy of Agricultural Sciences, Nanjing, Jiangsu 210014, China
| | - Guofeng Liu
- Institution of Agricultural Resource and Environmental Sciences, Jiangsu Academy of Agricultural Sciences, Nanjing, Jiangsu 210014, China
| | - Shaohua Yan
- Institution of Agricultural Resource and Environmental Sciences, Jiangsu Academy of Agricultural Sciences, Nanjing, Jiangsu 210014, China
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15
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Genotoxicity of microcystin-LR in in vitro and in vivo experimental models. BIOMED RESEARCH INTERNATIONAL 2014; 2014:949521. [PMID: 24955368 PMCID: PMC4052155 DOI: 10.1155/2014/949521] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/28/2014] [Accepted: 04/30/2014] [Indexed: 01/21/2023]
Abstract
Microcystin-LR (MCLR) is a cyanobacterial toxin known for its acute hepatotoxicity. Despite being recognized as tumour promoter, its genotoxicity is far from being completely clarified, particularly in organs other than liver. In this work, we used the comet and/or the micronucleus (MN) assays to study the genotoxicity of MCLR in kidney- (Vero-E6) and liver-derived (HepG2) cell lines and in blood cells from MCLR-exposed mice. MCLR treatment (5 and 20 μM) caused a significant induction in the MN frequency in both cell lines and, interestingly, a similar positive effect was observed in mouse reticulocytes (37.5 μg MCLR/kg, i.p. route). Moreover, the FISH-based analysis of the MN content (HepG2 cells) suggested that MCLR induces both chromosome breaks and loss. On the other hand, the comet assay results were negative in Vero-E6 cells and in mouse leukocytes, with the exception of a transient increase in the level of DNA damage 30 minutes after mice exposure. Overall, the present findings contributed to increase the weight of evidence in favour of MCLR genotoxicity, based on its capacity to induce permanent genetic damage either in vitro or in vivo. Moreover, they suggest a clastogenic and aneugenic mode of action that might underlie a carcinogenic effect.
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16
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Máthé C, M-Hamvas M, Vasas G. Microcystin-LR and cylindrospermopsin induced alterations in chromatin organization of plant cells. Mar Drugs 2013; 11:3689-717. [PMID: 24084787 PMCID: PMC3826130 DOI: 10.3390/md11103689] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2013] [Revised: 08/19/2013] [Accepted: 08/22/2013] [Indexed: 01/12/2023] Open
Abstract
Cyanobacteria produce metabolites with diverse bioactivities, structures and pharmacological properties. The effects of microcystins (MCYs), a family of peptide type protein-phosphatase inhibitors and cylindrospermopsin (CYN), an alkaloid type of protein synthesis blocker will be discussed in this review. We are focusing mainly on cyanotoxin-induced changes of chromatin organization and their possible cellular mechanisms. The particularities of plant cells explain the importance of such studies. Preprophase bands (PPBs) are premitotic cytoskeletal structures important in the determination of plant cell division plane. Phragmoplasts are cytoskeletal structures involved in plant cytokinesis. Both cyanotoxins induce the formation of multipolar spindles and disrupted phragmoplasts, leading to abnormal sister chromatid segregation during mitosis. Thus, MCY and CYN are probably inducing alterations of chromosome number. MCY induces programmed cell death: chromatin condensation, nucleus fragmentation, necrosis, alterations of nuclease and protease enzyme activities and patterns. The above effects may be related to elevated reactive oxygen species (ROS) and/or disfunctioning of microtubule associated proteins. Specific effects: MCY-LR induces histone H3 hyperphosphorylation leading to incomplete chromatid segregation and the formation of micronuclei. CYN induces the formation of split or double PPB directly related to protein synthesis inhibition. Cyanotoxins are powerful tools in the study of plant cell organization.
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Affiliation(s)
- Csaba Máthé
- Department of Botany, Faculty of Science and Technology, University of Debrecen, Debrecen H-4010, Egyetem tér 1, Hungary.
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Wang S, Tian D, Zheng W, Jiang S, Wang X, Andersen ME, Zheng Y, He G, Qu W. Combined exposure to 3-chloro-4-dichloromethyl-5-hydroxy-2(5H)-furanone and microsytin-LR increases genotoxicity in Chinese hamster ovary cells through oxidative stress. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2013; 47:1678-1687. [PMID: 23286199 DOI: 10.1021/es304541a] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
The disinfection byproducts 3-chloro-4-dichloromethyl-5-hydroxy-2(5H)-furanone (MX) and microcystins-LR (MC-LR), which are common contaminants in drinking water, often occur together in water sources in areas with high gastrointestinal tract cancer risks. While often studied alone, combination effects of these compounds are unknown. Here, we examine combined genotoxic responses to mixtures of MX and MC-LR using the Ames test, a cytokinesis-block micronuclei assay, and the comet assay with analysis for interactions by fractional analysis. We also evaluated a possible mechanism of genotoxicity by examining effects of the compounds on markers of oxidative stress. MX and MC-LR administrated jointly at noncytotoxic concentrations demonstrated significant interactions in the Ames test, the micronuclei assay, and the comet assay showing responses greater than those expected for additivity. Moreover, coexposure to MX and MC-LR significantly increased luciferase antioxidant response element activity, intracellular superoxide dismutase, catalase, glutathione, and reactive oxygen species production. In comparison with exposure to either compound alone, the mixtures of MX and MC-LR caused a less than additive effect on oxidative stress. Taken together, these results indicate that MC-LR exacerbates MX genotoxicity in low-dose combined exposure. This interaction may be enhanced by oxidative stress in the combined exposures.
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Affiliation(s)
- Shu Wang
- Department of Environmental Health, Key Laboratory of the Public Health Safety, Ministry of Education, School of Public Health, Fudan University, Shanghai 200032, China
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Zegura B, Gajski G, Straser A, Garaj-Vrhovac V, Filipič M. Microcystin-LR induced DNA damage in human peripheral blood lymphocytes. Mutat Res 2011; 726:116-122. [PMID: 22001196 DOI: 10.1016/j.mrgentox.2011.10.002] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2011] [Revised: 07/07/2011] [Accepted: 08/16/2011] [Indexed: 05/31/2023]
Abstract
Human exposure to microcystins, which are produced by freshwater cyanobacterial species, is of growing concern due to increasing appearance of cyanobacterial blooms as a consequence of global warming and increasing water eutrophication. Although microcystins are considered to be liver-specific, there is evidence that they may also affect other tissues. These substances have been shown to induce DNA damage in vitro and in vivo, but the mechanisms of their genotoxic activity remain unclear. In human peripheral blood lymphocytes (HPBLs) exposure to non-cytotoxic concentrations (0, 0.1, 1 and 10μg/ml) of microcystin-LR (MCLR) induced a dose- and time-dependent increase in DNA damage, as measured with the comet assay. Digestion of DNA from MCLR-treated HPBLs with purified formamidopyrimidine-DNA glycosylase (Fpg) displayed a greater number of DNA strand-breaks than non-digested DNA, confirming the evidence that MCLR induces oxidative DNA damage. With the cytokinesis-block micronucleus assay no statistically significant induction of micronuclei, nucleoplasmic bridges and nuclear buds was observed after a 24-h exposure to MCLR. At the molecular level, no changes in the expression of selected genes involved in the cellular response to DNA damage and oxidative stress were observed after a 4-h exposure to MCLR (1μg/ml). After 24h, DNA damage-responsive genes (p53, mdm2, gadd45a, cdkn1a), a gene involved in apoptosis (bax) and oxidative stress-responsive genes (cat, gpx1, sod1, gsr, gclc) were up-regulated. These results provide strong support that MCLR is an indirectly genotoxic agent, acting via induction of oxidative stress, and that lymphocytes are also the target of microcystin-induced toxicity.
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Affiliation(s)
- B Zegura
- National Institute of Biology, Department for Genetic Toxicology and Cancer Biology, Ljubljana, Slovenia.
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da Silva RRP, Pires OR, Grisolia CK. Genotoxicity in Oreochromis niloticus (Cichlidae) induced by Microcystis spp bloom extract containing microcystins. Toxicon 2011; 58:259-64. [PMID: 21704053 DOI: 10.1016/j.toxicon.2011.06.005] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2010] [Revised: 06/06/2011] [Accepted: 06/08/2011] [Indexed: 01/01/2023]
Abstract
Studies of genotoxicity in fish caused by cyanobacterial extracts containing microcystins (MCs) can be useful in determining their carcinogenic risk due to a genotoxic mechanism. An extract of cyanobacterial Microcystis ssp, containing MC-LR and -LA from a bloom collected in a eutrophic lake, showed genotoxicity to Oreochromis niloticus. DNA damage (comet assay) was significantly induced in peripheral erythrocytes with both tested concentrations of 6.90 μg kg(-1) bw and 13.80 μg kg(-1) bw through intraperitoneal injection (ip). There was no micronucleus induction after ip injection at concentrations of 6.90 μg kg(-1) bw and 13.80 μg kg(-1) bw. Body exposure resulted in micronucleus induction and DNA damage only at the highest tested concentrations of 103.72 μg L(-1). Thus, comet assay and ip injection revealed the highest levels of the genotoxicity of MCs. Apoptosis-necrosis test carried out at concentrations of 6.90 μg kg(-1) bw and 13.80 μg kg(-1) bw revealed that at low concentrations more apoptosis than necrosis occurred. At higher concentrations more necrosis than apoptosis occurred.
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Affiliation(s)
- R R Pavan da Silva
- Laboratório de Genética Toxicológica, Departamento de Genética e Morfologia, Instituto de Ciências Biológicas, Universidade de Brasília, 70910-900 Brasília - DF, Brazil
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Žegura B, Štraser A, Filipič M. Genotoxicity and potential carcinogenicity of cyanobacterial toxins – a review. MUTATION RESEARCH-REVIEWS IN MUTATION RESEARCH 2011; 727:16-41. [DOI: 10.1016/j.mrrev.2011.01.002] [Citation(s) in RCA: 184] [Impact Index Per Article: 14.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/31/2010] [Revised: 01/14/2011] [Accepted: 01/18/2011] [Indexed: 01/10/2023]
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