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Ji W, Ma J, Zheng Z, Al-Herrawy AZ, Xie B, Wu D. Algae blooms with resistance in fresh water: Potential interplay between Microcystis and antibiotic resistance genes. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 940:173528. [PMID: 38802023 DOI: 10.1016/j.scitotenv.2024.173528] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/26/2024] [Revised: 05/23/2024] [Accepted: 05/24/2024] [Indexed: 05/29/2024]
Abstract
Microcystis, a type of cyanobacteria known for producing microcystins (MCs), is experiencing a global increase in blooms. They have been recently recognized as potential contributors to the widespread of antibiotic resistance genes (ARGs). By reviewing approximately 150 pieces of recent studies, a hypothesis has been formulated suggesting that significant fluctuations in MCs concentrations and microbial community structure during Microcystis blooms could influence the dynamics of waterborne ARGs. Among all MCs, microcystin-LR (MC-LR) is the most widely distributed worldwide, notably abundant in reservoirs during summer. MCs inhibit protein phosphatases or increase reactive oxygen species (ROS), inducing oxidative stresses, enhancing membrane permeability, and causing DNA damage. This further enhances selective pressures and horizontal gene transfer (HGT) chances of ARGs. The mechanisms by which Microcystis regulates ARG dissemination have been systematically organized for the first time, focusing on the secretion of MCs and the alterations of bacterial community structure. However, several knowledge gaps remain, particularly concerning how MCs interfere with the electron transport chain and how Microcystis facilitates HGT of ARGs. Concurrently, the predominance of Microcystis forming the algal microbial aggregates is considered a hotspot for preserving and transferring ARGs. Yet, Microcystis can deplete the nutrients from other taxa within these aggregates, thereby reducing the density of ARG-carrying bacteria. Therefore, further studies are needed to explore the 'symbiotic - competitive' relationships between Microcystis and ARG-hosting bacteria under varied nutrient conditions. Addressing these knowledge gaps is crucial to understand the impacts of the algal aggregates on dynamics of waterborne antibiotic resistome, and underscores the need for effective control of Microcystis to curb the spread of antibiotic resistance. Constructed wetlands and photocatalysis represent advantageous strategies for halting the spread of ARGs from the perspective of Microcystis blooms, as they can effectively control Microcystis and MCs while maintaining the stability of aquatic ecosystem.
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Affiliation(s)
- Wenhui Ji
- Shanghai Engineering Research Center of Biotransformation of Organic Solid Waste, School of Ecological and Environmental Sciences, East China Normal University, Shanghai 200241, China; Key Laboratory of Northwest Water Resource, Environment and Ecology, MOE, Xi'an University of Architecture and Technology, Xi'an 710055, China; Chongqing Key Laboratory of Precision Optics, Chongqing Institute of East China Normal University, Chongqing 401120, China
| | - Jingkai Ma
- Shanghai Engineering Research Center of Biotransformation of Organic Solid Waste, School of Ecological and Environmental Sciences, East China Normal University, Shanghai 200241, China; Key Laboratory of Northwest Water Resource, Environment and Ecology, MOE, Xi'an University of Architecture and Technology, Xi'an 710055, China; Chongqing Key Laboratory of Precision Optics, Chongqing Institute of East China Normal University, Chongqing 401120, China
| | - Zhipeng Zheng
- Shanghai Engineering Research Center of Biotransformation of Organic Solid Waste, School of Ecological and Environmental Sciences, East China Normal University, Shanghai 200241, China; Key Laboratory of Northwest Water Resource, Environment and Ecology, MOE, Xi'an University of Architecture and Technology, Xi'an 710055, China; Chongqing Key Laboratory of Precision Optics, Chongqing Institute of East China Normal University, Chongqing 401120, China
| | - Ahmad Z Al-Herrawy
- Water Pollution Research Department, National Research Centre, Giza, Egypt
| | - Bing Xie
- Shanghai Engineering Research Center of Biotransformation of Organic Solid Waste, School of Ecological and Environmental Sciences, East China Normal University, Shanghai 200241, China
| | - Dong Wu
- Shanghai Engineering Research Center of Biotransformation of Organic Solid Waste, School of Ecological and Environmental Sciences, East China Normal University, Shanghai 200241, China; Key Laboratory of Northwest Water Resource, Environment and Ecology, MOE, Xi'an University of Architecture and Technology, Xi'an 710055, China; Chongqing Key Laboratory of Precision Optics, Chongqing Institute of East China Normal University, Chongqing 401120, China.
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Hu Z, Wang X, Zhang S, Zong W. Research on the discrepant inhibition mechanism of microcystin-LR disinfectant by-products target to protein phosphatase 1. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2021; 28:45586-45595. [PMID: 33871773 DOI: 10.1007/s11356-021-12472-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/25/2020] [Accepted: 01/11/2021] [Indexed: 06/12/2023]
Abstract
The secondary contamination for microcystin disinfection by-products (MC-DBPs) is of concern due to the residual toxic structure similar to their original toxins. To evaluate the toxicity of MC-DBPs, the discrepant inhibition mechanisms target to protein phosphatase 1 (PP1) were evaluated. Five typical MCLR-DBPs related to the oxidation of Adda5 were identified as C49H75N10O13Cl (+1Cl1OH, P1/P2), C34H54N10O12 (+2OH, P3/P4), and C49H76N10O14 (P5). Toxicity inhibition experiment on PP1 showed that the toxicity was in the sequence of MCLR > P3 > P1 > P4 > P2 > P5. Base on MOE molecular simulation, the discrepant inhibition mechanisms for MCLR and MCLR-DBPs target to PP1 were further clarified. The combination of MCLR/MCLR-DBPs to PP1 was mainly restrained by residues Adda5 and Arg4. Above key sites promoted the binding of MCLR/MCLR-DBPs to PP1 through the hydrogen bonds (H2O ← Adda5, Tyr134 → Adda5, H2O ← Arg4, Tyr134 → Arg4, Glu275 ← Arg4), ionic bonds (Asp197-Adda5, Glu275-Arg4, Asp220 → Arg4), and H-pi bonds (Trp206 ↔ Adda5, Ser129 ↔ Adda5). The oxidation of Adda5 also affected Mdha7 participated ionic bond Glu275-Mdha7 and Glu6 participated hydrogen bond H2O → Glu6. Besides, the "integral hydrogen bonds and ionic bonds" between toxin and PP1 also had important effects on the toxin toxicity. In this way, the inhibition of "Adda5 destroyed" MC-DBPs target to PP1 was regulated.
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Affiliation(s)
- Zhengxin Hu
- College of Geography and Environment, Shandong Normal University, 1# Daxue Road, Jinan, 250358, Shandong, China
| | - Xiaoning Wang
- College of Geography and Environment, Shandong Normal University, 1# Daxue Road, Jinan, 250358, Shandong, China
| | - Shuhan Zhang
- College of Geography and Environment, Shandong Normal University, 1# Daxue Road, Jinan, 250358, Shandong, China
| | - Wansong Zong
- College of Geography and Environment, Shandong Normal University, 1# Daxue Road, Jinan, 250358, Shandong, China.
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Yilmaz S, Ülger TG, Göktaş B, Öztürk Ş, Karataş DÖ, Beyzi E. Cyanotoxin genotoxicity: a review. TOXIN REV 2021. [DOI: 10.1080/15569543.2021.1922922] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Affiliation(s)
- Serkan Yilmaz
- Department of Midwifery, Faculty of Nursing, University of Ankara, Institute for Forensic Sciences, Ankara, Turkey
| | - Taha Gökmen Ülger
- Department of Nutrition and Dietetics, Faculty of Health Sciences, Bolu Abant İzzet Baysal University, Bolu, Turkey
| | - Bayram Göktaş
- Department of Health Management, Faculty of Health Sciences, University of Ankara, Ankara, Turkey
| | - Şahlan Öztürk
- Department of Environmental Engineering, Faculty of Engineering, Nevşehir Hacı Bektaş Veli University, Nevşehir, Turkey
| | - Duygu Öztaş Karataş
- Department of Midwifery, Faculty of Nursing, University of Ankara, Ankara, Turkey
| | - Ebru Beyzi
- Vocational School of Health Services, University of Gazi, Ankara, Turkey
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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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Alosman M, Cao L, Massey IY, Yang F. The lethal effects and determinants of microcystin-LR on heart: a mini review. TOXIN REV 2020. [DOI: 10.1080/15569543.2019.1711417] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Affiliation(s)
- Muwaffak Alosman
- Department of Occupational and Environmental Health, Xiangya School of Public Health, Central South University, Changsha, China
| | - Linghui Cao
- Department of Occupational and Environmental Health, Xiangya School of Public Health, Central South University, Changsha, China
| | - Isaac Yaw Massey
- Department of Occupational and Environmental Health, Xiangya School of Public Health, Central South University, Changsha, China
| | - Fei Yang
- Department of Occupational and Environmental Health, Xiangya School of Public Health, Central South University, Changsha, China
- Key laboratory of Hunan Province for Water Environment and Agriculture Product Safety, Central South University, Changsha, China
- Key Laboratory of Environmental Medicine Engineering, Ministry of Education, School of Public Health, Southeast University, Nanjing, China
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Krishnan A, Koski G, Mou X. Characterization of microcystin-induced apoptosis in HepG2 hepatoma cells. Toxicon 2019; 173:20-26. [PMID: 31734250 DOI: 10.1016/j.toxicon.2019.11.003] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2019] [Revised: 11/01/2019] [Accepted: 11/11/2019] [Indexed: 12/25/2022]
Abstract
Microcystins (MCs) are a class of hepatotoxins that are commonly produced by freshwater cyanobacteria. MCs harm liver cells through inhibiting protein phosphatases 1 and 2A (PP1 and PP2A) and can produce dualistic effects, i.e., cell death and uncontrolled cellular proliferation. The induction of programmed cell death, i.e., apoptosis, in MC treated hepatic cells has been described previously; however, its exact pathway remains unclear. To address this, HepG2 human hepatoma cells were exposed to MC-LR, the most prevalent isomer of MCs, and morphological and physiological responses were examined. Microscopy and Alamar Blue assay showed that HepG2 cells responded to MC-LR treatment with apoptosis characteristics, such as clumping and shrinking of cells and detachment from the monolayer culture surface. A fluorescent caspase activation assay further revealed activation of all tested apoptosis-dependent caspases (i.e., caspase-3/7, 8 and 9) after 24 h of MC-LR treatment. Furthermore, caspase-8 was found being activated 4 h after MC-LR treatment, earlier than observed activation of caspase-9 (8 h after MC-LR treatment). These data demonstrated that MC-LR can induce apoptosis of HepG2 cells through both extrinsic and intrinsic pathways and that the extrinsic pathway may be activated before the intrinsic pathway. This indicates that extrinsic pathway is more sensitive than intrinsic pathway in MC induced apoptosis. This knowledge contributes to a better understanding of MC hepatotoxicity and can be further used for developing treatments for MC exposed hepatic cells.
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Affiliation(s)
- Anjali Krishnan
- Biological Science Department, Kent State University, Kent, OH 44242, United States
| | - Gary Koski
- Biological Science Department, Kent State University, Kent, OH 44242, United States
| | - Xiaozhen Mou
- Biological Science Department, Kent State University, Kent, OH 44242, United States.
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Pamplona-Silva MT, Gonçalves LC, Marin-Morales MA. Genetic toxicity of water contaminated by microcystins collected during a cyanobacteria bloom. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2018; 166:223-230. [PMID: 30269018 DOI: 10.1016/j.ecoenv.2018.09.090] [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: 05/09/2018] [Revised: 09/10/2018] [Accepted: 09/21/2018] [Indexed: 06/08/2023]
Abstract
Microcystin-LR (MCLR) is a toxin mainly produced by Microcystis aeruginosa, cyanobacteria most commonly found in eutrophic environments. Cyanobacteria blooms have affected Salto Grande reservoir (Americana, State of São Paulo/Brazil) for several decades, often observed during periods of drought. In this study, the genotoxic effects of MCLR (95% purity) and water samples contaminated by this toxin were evaluated during cyanobacteria bloom using assays with the test organism Allium cepa. The results showed genotoxic action for pure microcystin and cytotoxic, genotoxic and mutagenic action for water samples collected during flowering. Chromosomal aberration assays have shown that MCLR induces chromosomal breaks that persist in the daughter cells as MN. Therefore, it is possible to infer a clastogenic action for this toxin. The MCLR present in the environmental samples was shown to be more cytogenotoxic for the cells than the different concentrations tested in this study with the pure substance. This amplified toxic action can be related to a synergistic effect between the MCLR and other compounds present in the environmental samples. The genotoxicity studies with MCLR show inconsistent and inconclusive results, so this toxin needs to be better investigated in order to obtain further information about the action mode of it is on the biological system.
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Affiliation(s)
- Maria Tereza Pamplona-Silva
- São Paulo State University (Unesp), Institute of Bioscience, Rio Claro. Av. 24-A, 1515, 13.506-900 Rio Claro, SP, Brazil.
| | - Letícia Cristina Gonçalves
- São Paulo State University (Unesp), Institute of Bioscience, Rio Claro. Av. 24-A, 1515, 13.506-900 Rio Claro, SP, Brazil.
| | - Maria Aparecida Marin-Morales
- São Paulo State University (Unesp), Institute of Bioscience, Rio Claro. Av. 24-A, 1515, 13.506-900 Rio Claro, SP, Brazil.
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Pichardo S, Cameán AM, Jos A. In Vitro Toxicological Assessment of Cylindrospermopsin: A Review. Toxins (Basel) 2017; 9:toxins9120402. [PMID: 29258177 PMCID: PMC5744122 DOI: 10.3390/toxins9120402] [Citation(s) in RCA: 56] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2017] [Revised: 12/12/2017] [Accepted: 12/13/2017] [Indexed: 12/29/2022] Open
Abstract
Cylindrospermopsin (CYN) is a cyanobacterial toxin that is gaining importance, owing to its increasing expansion worldwide and the increased frequency of its blooms. CYN mainly targets the liver, but also involves other organs. Various mechanisms have been associated with its toxicity, such as protein synthesis inhibition, oxidative stress, etc. However, its toxic effects are not yet fully elucidated and additional data for hazard characterization purposes are required. In this regard, in vitro methods can play an important role, owing to their advantages in comparison to in vivo trials. The aim of this work was to compile and evaluate the in vitro data dealing with CYN available in the scientific literature, focusing on its toxicokinetics and its main toxicity mechanisms. This analysis would be useful to identify research needs and data gaps in order to complete knowledge about the toxicity profile of CYN. For example, it has been shown that research on various aspects, such as new emerging toxicity effects, the toxicity of analogs, or the potential interaction of CYN with other cyanotoxins, among others, is still very scarce. New in vitro studies are therefore welcome.
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Affiliation(s)
- Silvia Pichardo
- 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.
| | - Angeles Jos
- Area of Toxicology, Faculty of Pharmacy, University of Sevilla, C/Profesor García González 2, 41012 Sevilla, Spain.
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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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Zheng C, Zeng H, Lin H, Wang J, Feng X, Qiu Z, Chen JA, Luo J, Luo Y, Huang Y, Wang L, Liu W, Tan Y, Xu A, Yao Y, Shu W. Serum microcystin levels positively linked with risk of hepatocellular carcinoma: A case-control study in southwest China. Hepatology 2017; 66:1519-1528. [PMID: 28599070 DOI: 10.1002/hep.29310] [Citation(s) in RCA: 101] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/12/2016] [Revised: 05/18/2017] [Accepted: 06/06/2017] [Indexed: 12/13/2022]
Abstract
UNLABELLED Microcystins have been reported to be carcinogenic by animal and cell experimentation, but there are no data on the linkage between serum microcystins and hepatocellular carcinoma (HCC) risk in humans. We conducted a clinical case-control study to investigate the association between serum microcystins and HCC risk after controlling several known risk factors, such as hepatitis B virus, alcohol, and aflatoxin. From December 2013 to May 2016, 214 patients newly diagnosed with HCC along with 214 controls (frequency-matched by age and sex) were recruited from three hospitals in Chongqing, southwest China. Basic information on lifestyle and history of disease was obtained by questionnaire. Blood samples were collected and analyzed for serum microcystin-LR (MC-LR) and aflatoxin-albumin adduct by enzyme-linked immunosorbent assay and for hepatitis B surface antigen status by chemiluminescence assay. Binary logistic regression analyses were performed to assess the independent effects of MC-LR and its joint effects with other factors on HCC risk. The adjusted odds ratio for HCC risk by serum MC-LR was 2.9 (95% confidence interval [CI], 1.5-5.5) in all patients. Notably, a clear relationship between increased MC-LR level (Q2, Q3, and Q4) and HCC risk was observed with elevated adjusted odds ratios (1.3, 2.6, and 4.0, respectively). Positive interactions with the additive model were investigated between MC-LR and hepatitis B virus infection (synergism index = 3.0; 95% CI, 2.0-4.5) and between MC-LR and alcohol (synergism index = 4.0; 95% CI, 1.7-9.5), while a negative interaction was found between MC-LR and aflatoxin (synergism index = 0.4; 95% CI, 0.3-0.7). Additionally, serum MC-LR was significantly associated with tumor differentiation (r = -0.228, P < 0.001). CONCLUSION We provide evidence that serum MC-LR was an independent risk factor for HCC in humans, with an obvious positive interaction with hepatitis B virus and alcohol but a negative interaction with aflatoxin. (Hepatology 2017;66:1519-1528).
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Affiliation(s)
- Chuanfen Zheng
- Department of Environmental Hygiene, College of Preventive Medicine, Chongqing, China
| | - Hui Zeng
- Department of Environmental Hygiene, College of Preventive Medicine, Chongqing, China
| | - Hui Lin
- Department of Tropical Epidemiology, College of Preventive Medicine, Chongqing, China
| | - Jia Wang
- Department of Environmental Hygiene, College of Preventive Medicine, Chongqing, China
| | - Xiaobin Feng
- Institute of Hepatobiliary Surgery, Southwest Hospital, Chongqing, China
| | - Zhiqun Qiu
- Department of Environmental Hygiene, College of Preventive Medicine, Chongqing, China
| | - Ji-An Chen
- Department of Health Education, College of Preventive Medicine, Chongqing, China
| | - Jiaohua Luo
- Department of Environmental Hygiene, College of Preventive Medicine, Chongqing, China
| | - Yang Luo
- Center for Nanomedicine, Southwest Hospital, Third Military Medical University, Chongqing, China
| | - Yujing Huang
- Department of Environmental Hygiene, College of Preventive Medicine, Chongqing, China
| | - Lingqiao Wang
- Department of Environmental Hygiene, College of Preventive Medicine, Chongqing, China
| | - Wenyi Liu
- Department of Environmental Hygiene, College of Preventive Medicine, Chongqing, China
| | - Yao Tan
- Department of Environmental Hygiene, College of Preventive Medicine, Chongqing, China
| | - Anwei Xu
- Department of Environmental Hygiene, College of Preventive Medicine, Chongqing, China
| | - Yuan Yao
- Department of Environmental Hygiene, College of Preventive Medicine, Chongqing, China
| | - Weiqun Shu
- Department of Environmental Hygiene, College of Preventive Medicine, Chongqing, China
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Chen L, Chen J, Zhang X, Xie P. A review of reproductive toxicity of microcystins. JOURNAL OF HAZARDOUS MATERIALS 2016; 301:381-99. [PMID: 26521084 DOI: 10.1016/j.jhazmat.2015.08.041] [Citation(s) in RCA: 233] [Impact Index Per Article: 29.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/19/2015] [Revised: 08/20/2015] [Accepted: 08/23/2015] [Indexed: 05/25/2023]
Abstract
Animal studies provide strong evidence of positive associations between microcystins (MCs) exposure and reproductive toxicity, representing a threat to human reproductive health and the biodiversity of wild life. This paper reviews current knowledge of the reproductive toxicity of MCs, with regard to mammals, fishes, amphibians, and birds, mostly in males. Toxicity of MCs is primarily governed by the inhibition of protein phosphatases 1 and 2A (PP1 and PP2A) and disturbance of cellular phosphorylation balance. MCs exposure is related to excessive production of reactive oxygen species (ROS) and oxidative stress, leading to cytoskeleton disruption, mitochondria dysfunction, endoplasmic reticulum (ER) stress, and DNA damage. MCs induce cell apoptosis mediated by the mitochondrial and ROS and ER pathways. Through PP1/2A inhibition and oxidative stress, MCs lead to differential expression/activity of transcriptional factors and proteins involved in the pathways of cellular differentiation, proliferation, and tumor promotion. MC-induced DNA damage is also involved in carcinogenicity. Apart from a direct effect on testes and ovaries, MCs indirectly affect sex hormones by damaging the hypothalamic-pituitary-gonad (HPG) axis and liver. Parental exposure to MCs may result in hepatotoxicity and neurotoxicity of offspring. We also summarize the current research gaps which should be addressed by further studies.
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Affiliation(s)
- Liang Chen
- Donghu Experimental Station of Lake Ecosystems, State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China; University of Chinese Academy of Sciences, Beijing 100049, China.
| | - Jun Chen
- Donghu Experimental Station of Lake Ecosystems, State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China.
| | - Xuezhen Zhang
- College of Fisheries, Huazhong Agricultural University, Freshwater Aquaculture Collaborative Innovation Center of Hubei Province, Wuhan 430070, China.
| | - Ping Xie
- Donghu Experimental Station of Lake Ecosystems, State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China.
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Li X, Zhao Q, Zhou W, Xu L, Wang Y. Effects of chronic exposure to microcystin-LR on hepatocyte mitochondrial DNA replication in mice. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2015; 49:4665-4672. [PMID: 25723732 DOI: 10.1021/es5059132] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Microcystins (MCs) are produced by cyanobacterial blooms, and microcystin-LR (MC-LR) is the most toxic among the 80 MC variants. Data have shown that the liver is one of the specific target organs for MC-LR, which can cause mitochondrial DNA (mtDNA) damage, resulting in mitochondrial dysfunction. However, the underlying mechanism is still unclear. In the present study, we evaluated the genetic toxicity of MC-LR in mice drinking water at different concentrations (1, 5, 10, 20, and 40 μg/L) for 12 months. Our results showed that long-term and persistent exposure to MC-LR increased the 8-hydroxy-2'-deoxyguanosine (8-OHdG) levels of DNA in liver cells, damaged the integrity of mtDNA and nuclear DNA (nDNA), and altered the mtDNA content. Notably, MC-LR exposure can change the expression of mitochondrial genes and nuclear genes that are critical for regulating mtDNA replication and repairing oxidized DNA. They also further impaired the function of mitochondria and liver cells.
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Affiliation(s)
- Xinxiu Li
- †Department of Medical Genetics, and ‡Jiangsu Key Laboratory of Molecular Medicine, Nanjing University School of Medicine, Nanjing, Jiangsu 210093, People's Republic of China
| | - Qingya Zhao
- †Department of Medical Genetics, and ‡Jiangsu Key Laboratory of Molecular Medicine, Nanjing University School of Medicine, Nanjing, Jiangsu 210093, People's Republic of China
| | - Wei Zhou
- †Department of Medical Genetics, and ‡Jiangsu Key Laboratory of Molecular Medicine, Nanjing University School of Medicine, Nanjing, Jiangsu 210093, People's Republic of China
| | - Lizhi Xu
- †Department of Medical Genetics, and ‡Jiangsu Key Laboratory of Molecular Medicine, Nanjing University School of Medicine, Nanjing, Jiangsu 210093, People's Republic of China
| | - Yaping Wang
- †Department of Medical Genetics, and ‡Jiangsu Key Laboratory of Molecular Medicine, Nanjing University School of Medicine, Nanjing, Jiangsu 210093, People's Republic of China
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Huang JL, Lin CS, Chang CC, Lu YN, Hsu YL, Wong TY, Wang YF. Human JC virus small tumour antigen inhibits nucleotide excision repair and sensitises cells to DNA-damaging agents. Mutagenesis 2015; 30:475-85. [PMID: 25744060 DOI: 10.1093/mutage/gev004] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
The human JC virus (JCV) is potentially carcinogenic to humans as a Group 2B carcinogen, and it is ubiquitous in human populations. To investigate whether the small tumour (ST) antigen of the JCV contributes to genomic instability, we established cell lines stably expressing the JCV ST and examined its role in DNA repair. Results from host cell reactivation (HCR) assay revealed that the established cell lines exhibited lower nucleotide excision repair (NER) activity than the vector control cells did. The presence of γ-H2AX, a marker of DNA damage, indicated that the established cell line contained more DNA damage foci compared with vector control cells. Furthermore, the results of clonogenic analyses indicated that the JCV ST-expressing cells were more sensitive than the vector control cells to ultraviolet (UV) irradiation and cisplatin treatment. Micronuclei formation assay revealed that the JCV ST-positive cells presented more chromosomal breakages than did the JCV ST-negative cells, particularly after exposure to DNA-damaging agents. The xeroderma pigmentosum Group D protein, a DNA helicase involved in NER, was downregulated in the JCV ST-positive cells in response to UV irradiation. The effect of the protein phosphatase 2A (PP2A) inhibitor okadaic acid on NER was similar to that of the ST, which is a PP2A-binding protein. Therefore, the deactivation of the PP2A might underlie ST-mediated NER inhibition. The results of this study indicate that exposing JCV ST-positive cells to DNA-damaging agents causes genomic instability, which contributes to carcinogenesis. Our data provide further evidence on the association between the JCV ST and human cancer.
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Affiliation(s)
- Jau-Ling Huang
- Department of Bioscience Technology, College of Health Science, Chang Jung Christian University, Tainan, Taiwan, Graduate Institute of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan, Department of Biological Sciences, National Sun Yat-sen University, Kaohsiung, Taiwan, Division of Nephrology, Department of Internal Medicine, Changhua Christian Hospital, Changhua, Taiwan, School of Medicine, Chung Shan Medical University, Taichung, Taiwan
| | - Chang-Shen Lin
- Graduate Institute of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan, Department of Biological Sciences, National Sun Yat-sen University, Kaohsiung, Taiwan
| | - Chia-Chu Chang
- Division of Nephrology, Department of Internal Medicine, Changhua Christian Hospital, Changhua, Taiwan, School of Medicine, Chung Shan Medical University, Taichung, Taiwan
| | - Yu-Ning Lu
- Department of Bioscience Technology, College of Health Science, Chang Jung Christian University, Tainan, Taiwan, Graduate Institute of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan, Department of Biological Sciences, National Sun Yat-sen University, Kaohsiung, Taiwan, Division of Nephrology, Department of Internal Medicine, Changhua Christian Hospital, Changhua, Taiwan, School of Medicine, Chung Shan Medical University, Taichung, Taiwan
| | - Yu-Ling Hsu
- Department of Bioscience Technology, College of Health Science, Chang Jung Christian University, Tainan, Taiwan, Graduate Institute of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan, Department of Biological Sciences, National Sun Yat-sen University, Kaohsiung, Taiwan, Division of Nephrology, Department of Internal Medicine, Changhua Christian Hospital, Changhua, Taiwan, School of Medicine, Chung Shan Medical University, Taichung, Taiwan
| | - Tzyy-Yue Wong
- Department of Bioscience Technology, College of Health Science, Chang Jung Christian University, Tainan, Taiwan, Graduate Institute of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan, Department of Biological Sciences, National Sun Yat-sen University, Kaohsiung, Taiwan, Division of Nephrology, Department of Internal Medicine, Changhua Christian Hospital, Changhua, Taiwan, School of Medicine, Chung Shan Medical University, Taichung, Taiwan
| | - Yu-Fei Wang
- Department of Bioscience Technology, College of Health Science, Chang Jung Christian University, Tainan, Taiwan, Graduate Institute of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan, Department of Biological Sciences, National Sun Yat-sen University, Kaohsiung, Taiwan, Division of Nephrology, Department of Internal Medicine, Changhua Christian Hospital, Changhua, Taiwan, School of Medicine, Chung Shan Medical University, Taichung, Taiwan
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15
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Wang X, Huang P, Liu Y, Du H, Wang X, Wang M, Wang Y, Hei TK, Wu L, Xu A. Role of nitric oxide in the genotoxic response to chronic microcystin-LR exposure in human-hamster hybrid cells. J Environ Sci (China) 2015; 29:210-218. [PMID: 25766030 DOI: 10.1016/j.jes.2014.07.036] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2014] [Revised: 05/19/2014] [Accepted: 07/24/2014] [Indexed: 06/04/2023]
Abstract
Microcystin-LR (MC-LR) is the most abundant and toxic microcystin congener and has been classified as a potential human carcinogen (Group 2B) by the International Agency for Research on Cancer. However, the mechanisms underlying the genotoxic effects of MC-LR during chronic exposure are still poorly understood. In the present study, human-hamster hybrid (AL) cells were exposed to MC-LR for varying lengths of time to investigate the role of nitrogen radicals in MC-LR-induced genotoxicity. The mutagenic potential at the CD59 locus was more than 2-fold higher (p<0.01) in AL cells exposed to a cytotoxic concentration (1 μmol/L) of MC-LR for 30 days than in untreated control cells, which was consistent with the formation of micronucleus. MC-LR caused a dose-dependent increase in nitric oxide (NO) production in treated cells. Moreover, this was blocked by concurrent treatment with the NO synthase inhibitor NG-methyl-L-arginine (L-NMMA), which suppressed MC-LR-induced mutations as well. The survival of mitochondrial DNA-depleted (ρ0) AL cells was markedly decreased by MC-LR treatment compared to that in AL cells, while the CD59 mutant fraction was unaltered. These results provided clear evidence that the genotoxicity associated with chronic MC-LR exposure in mammalian cells was mediated by NO and might be considered as a basis for the development of therapeutics that prevent carcinogenesis.
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Affiliation(s)
- Xiaofei Wang
- Key Laboratory of Ion Beam Bioengineering, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei 230031, Anhui, China; Institute of Intelligent Machines, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei 230031, Anhui, China.
| | - Pei Huang
- Key Laboratory of Ion Beam Bioengineering, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei 230031, Anhui, China.
| | - Yun Liu
- Key Laboratory of Ion Beam Bioengineering, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei 230031, Anhui, China
| | - Hua Du
- Key Laboratory of Ion Beam Bioengineering, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei 230031, Anhui, China
| | - Xinan Wang
- Key Laboratory of Ion Beam Bioengineering, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei 230031, Anhui, China
| | - Meimei Wang
- Key Laboratory of Ion Beam Bioengineering, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei 230031, Anhui, China
| | - Yichen Wang
- Key Laboratory of Ion Beam Bioengineering, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei 230031, Anhui, China
| | - Tom K Hei
- Center for Radiological Research, College of Physicians & Surgeons, Columbia University, New York, NY 10032, USA
| | - Lijun Wu
- Key Laboratory of Ion Beam Bioengineering, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei 230031, Anhui, China
| | - An Xu
- Key Laboratory of Ion Beam Bioengineering, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei 230031, Anhui, China.
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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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17
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Zong W, Sun F, Sun X. Evaluation on the generative mechanism and biological toxicity of microcystin-LR disinfection by-products formed by chlorination. JOURNAL OF HAZARDOUS MATERIALS 2013; 252-253:293-299. [PMID: 23542323 DOI: 10.1016/j.jhazmat.2013.03.010] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/07/2012] [Revised: 02/09/2013] [Accepted: 03/06/2013] [Indexed: 06/02/2023]
Abstract
To control the environmental risk of microcystin-LR disinfection by-products (MCLR-DBPs), we evaluated their generative mechanisms and biological toxicity by mass spectrometry technology and protein phosphatase inhibition assay. Subject to chlorination, MCLR was totally transformed within 45 min and generated 5 types of MCLR-DBPs with the chemical formulas of C34H54N10O12, C49H76N10O14Cl2, C49H77N10O15Cl, C49H75N10O13Cl, and C49H76N10O14. Isomers for each MCLR-DBP type were identified and separated (products 1-9), indicating that the conjugated diene in Adda residue was a major target site of disinfection. Though, subsequent toxicity test showed the toxicity of MCLR-DBPs on protein phosphatase 1 decreased with the extending of disinfection by and large, these DBPs still possessed certain biological toxicity (especially for product 5). Combined with quantitative analysis, we thought the secondary pollution of MCLR-DBPs in drinking water also deserved further attention. This study offers valid technique support for MCLR-DBPs identification, contributes to a comprehensive cognition on their hazard, and thus has great significance to prevent and control the environmental risk induced by microcystins and their DBPs.
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Affiliation(s)
- Wansong Zong
- College of Population, Resources and Environment, Shandong Normal University, 88# East Wenhua Road, Jinan 250014, PR China.
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18
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Santos PVF, Lopes IC, Diculescu VC, Oliveira-Brett AM. DNA - Cyanobacterial Hepatotoxins Microcystin-LR and Nodularin Interaction: Electrochemical Evaluation. ELECTROANAL 2012. [DOI: 10.1002/elan.201100516] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
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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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20
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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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Campos A, Vasconcelos V. Molecular mechanisms of microcystin toxicity in animal cells. Int J Mol Sci 2010; 11:268-287. [PMID: 20162015 PMCID: PMC2821003 DOI: 10.3390/ijms11010268] [Citation(s) in RCA: 347] [Impact Index Per Article: 24.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2009] [Revised: 01/11/2010] [Accepted: 01/12/2010] [Indexed: 12/31/2022] Open
Abstract
Microcystins (MC) are potent hepatotoxins produced by the cyanobacteria of the genera Planktothrix, Microcystis, Aphanizomenon, Nostoc and Anabaena. These cyclic heptapeptides have strong affinity to serine/threonine protein phosphatases (PPs) thereby acting as an inhibitor of this group of enzymes. Through this interaction a cascade of events responsible for the MC cytotoxic and genotoxic effects in animal cells may take place. Moreover MC induces oxidative stress in animal cells and together with the inhibition of PPs, this pathway is considered to be one of the main mechanisms of MC toxicity. In recent years new insights on the key enzymes involved in the signal-transduction and toxicity have been reported demonstrating the complexity of the interaction of these toxins with animal cells. Key proteins involved in MC up-take, biotransformation and excretion have been identified, demonstrating the ability of aquatic animals to metabolize and excrete the toxin. MC have shown to interact with the mitochondria. The consequences are the dysfunction of the organelle, induction of reactive oxygen species (ROS) and cell apoptosis. MC activity leads to the differential expression/activity of transcriptional factors and protein kinases involved in the pathways of cellular differentiation, proliferation and tumor promotion activity. This activity may result from the direct inhibition of the protein phosphatases PP1 and PP2A. This review aims to summarize the increasing data regarding the molecular mechanisms of MC toxicity in animal systems, reporting for direct MC interacting proteins and key enzymes in the process of toxicity biotransformation/excretion of these cyclic peptides.
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Affiliation(s)
- Alexandre Campos
- Centro Interdisciplinar de Investigação Marinha e Ambiental, CIIMAR/CIMAR, Rua dos Bragas 289, 4050-123 Porto, Portugal; E-Mail:
- Author to whom correspondence should be addressed; E-Mail:
; Tel.: +351-223-401-813; Fax: +351-223-390-608
| | - Vitor Vasconcelos
- Centro Interdisciplinar de Investigação Marinha e Ambiental, CIIMAR/CIMAR, Rua dos Bragas 289, 4050-123 Porto, Portugal; E-Mail:
- Departamento de Biologia, Faculdade de Ciências da Universidade do Porto, Rua do Campo Alegre, 4069-007 Porto, Portugal
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Malécot M, Mezhoud K, Marie A, Praseuth D, Puiseux-Dao S, Edery M. Proteomic study of the effects of microcystin-LR on organelle and membrane proteins in medaka fish liver. AQUATIC TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2009; 94:153-161. [PMID: 19628287 DOI: 10.1016/j.aquatox.2009.06.012] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/16/2009] [Revised: 06/16/2009] [Accepted: 06/19/2009] [Indexed: 05/28/2023]
Abstract
The microcystin-leucine-arginine toxin (MC-LR) is produced by cyanobacteria that sometimes bloom in water reservoirs. It targets the liver, thus posing potential health risks to human and animals. Microcystin inhibits the protein phosphatases PP1 and PP2A, leading to diverse cellular deregulation processes. A proteomic approach was applied to the medaka fish (Oryzias latipes) to obtain an overview of the effects of MC-LR on the liver. As membrane and organelle proteins are major structural and functional components of several cell signalling pathways, we decided to investigate here the membrane and organelle-enriched fractions from the livers of control and MC-LR treated medaka fish. Seventeen proteins were identified by proteomic analysis as being modulated in response to MC-LR treatment. This is the first time for eight of them to be reported as being involved in MC-LR effects: prohibitin, fumarylacetoacetase, protein disulfide isomerase A4 and A6, glucose regulated protein 78kDa, 40S ribosomal protein SA, cytochrome b5, and ATP synthase mitochondrial d subunit. These proteins are involved in protein maturation or in the response to oxidative stress highlighting the role of organelles in protein processing and the complex cooperation associated with oxidative stress.
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Affiliation(s)
- Mélodie Malécot
- CNRS, FRE 3206 Molécules de communication et adaptation des microorganismes, and MNHN, USM 505 Cyanobactéries, cyanotoxines et environnement, Département Régulations, développement et diversité moléculaire, Muséum national d'Histoire naturelle, Paris Cedex 05, France
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Gaudin J, Le Hegarat L, Nesslany F, Marzin D, Fessard V. In vivo genotoxic potential of microcystin-LR: a cyanobacterial toxin, investigated both by the unscheduled DNA synthesis (UDS) and the comet assays after intravenous administration. ENVIRONMENTAL TOXICOLOGY 2009; 24:200-209. [PMID: 18561296 DOI: 10.1002/tox.20417] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Microcystin-LR (MC-LR) is a toxin produced by freshwater cyanobacteria and is a potential threat to human health. MC-LR has been shown to be both a specific inhibitor of serine/threonine protein phosphatases PP1 and PP2A and a potent tumor promoter in rat liver. However, the genotoxic potential of MCs remains unclear. In this article, we investigated the ability of MC-LR to induce DNA damage on rat hepatocytes following intravenous (iv) administration by using two in vivo genotoxicity assays: the unscheduled DNA synthesis (UDS) and the comet assays. The UDS assay measures DNA synthesis induced from the excision repair of DNA damaged regions and the comet assay is a very sensitive technique for detecting various forms of DNA damage. After an exposure time of 2-4 h or 12-16 h and a dose ranging from 12.5 to 50 microg/kg bw, no DNA damage could be observed in both assays on rat hepatocytes following iv administration. These findings have been discussed and compared with recently published genotoxic results obtained in other organs from mice after oral and intraperitoneal treatments to better understand the mechanism of action of this toxin in relation with its cancerogenicity potential.
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Affiliation(s)
- Julien Gaudin
- AFSSA, Agence Française de Sécurité Sanitaire des Aliments, Laboratoire d'Etudes et de Recherches sur Médicaments Vétérinaires et Désinfectants, Unité de Toxicologie Génétique des Contaminants Alimentaire, La Haute Marche, 35302 Fougères Cedex, France
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Lankoff A, Sochacki J, Spoof L, Meriluoto J, Wojcik A, Wegierek A, Verschaeve L. Nucleotide excision repair impairment by nodularin in CHO cell lines due to ERCC1/XPF inactivation. Toxicol Lett 2008; 179:101-7. [PMID: 18514445 DOI: 10.1016/j.toxlet.2008.04.008] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2008] [Revised: 04/13/2008] [Accepted: 04/16/2008] [Indexed: 11/19/2022]
Abstract
The problem of toxicity of cyanobacterial toxins is of increasing concern, as the incidence of such blooms grows. Among the toxins, the most abundant in the environment are hepatotoxins known as nodularins and microcystins. These toxins are responsible for almost all known cases of fresh and brackish water intoxication and are responsible for recurrent episodes of human and animal illness and death. Moreover, they are believed to be potent tumor promoters and initiators. However, the mechanisms by which these toxins induce liver cancer are not well understood. The aim of the present study was to determine the effect of nodularin on the kinetics of nucleotide excision repair (NER) in Chinese hamster ovary (CHO) cells exposed to UV radiation. The first set of experiments was performed to define the optimal treatment conditions for nodularin to avoid the possibility of encountering false positive signals in the comet assay due to the apoptogenic activity of nodularin. Based on the analysis of apoptosis, the 6-h treatment time of cells with nodularin (1mug/ml, 10mug/ml and 20mug/ml) was chosen for the alkaline comet assay. The kinetics of NER was determined in CHO cell lines: AA8 (wild-type) and mutant cell lines: UV135 (XPG(-)), UV41 (XPF(-)) and UV20 (ERCC1(-)) exposed to 20J/m(2) UV radiation. The micronucleus assay was performed to determine a residual DNA damage in four cell lines treated with nodularin (10mug/ml) and exposed to equitoxic doses UV radiation. Radiation doses of UV producing 50% of survival for AA8, UV135, UV20 and UV41 cell lines were calculated from UV survival curves. The results show that nodularin impairs the incision/excision step of NER in CHO cells by the ERCC1/XPF inactivation and leads to an increased level of UV-induced cytogenetic DNA damage.
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Affiliation(s)
- A Lankoff
- Department of Radiobiology and Immunology, Institute of Biology, Jan Kochanowski University, ul. Swietokrzyska 15, 25-406 Kielce, Poland.
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Sun Y, Tang R, Li D, Zhang X, Fu J, Xie P. Acute effects of microcystins on the transcription of antioxidant enzyme genes in crucian carp Carassius auratus. ENVIRONMENTAL TOXICOLOGY 2008; 23:145-152. [PMID: 18214919 DOI: 10.1002/tox.20317] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Recent evidences suggested that oxidative stress may play a significant role in the pathogenesis of MCs toxicity. In the present study, the acute effects of microcystins on the transcription of antioxidant enzyme genes were investigated in liver of crucian carp i.p.-injected with 50 mug MC-LReq per kg body weight (BW). We reported the cDNA sequences for four kinds of antioxidant enzyme (GSH-PX, CAT, Cu/Zn SOD, and GR) genes, and evaluated the oxidant stress induced by MCs through analyzing the transcription abundance of antioxidant enzyme genes using real-time PCR method. The time-dependent change of relative transcription abundance and expression of the antioxidant enzyme genes were determined at 1, 3, 12, 24, and 48 h. The transcription abundance varied among antioxidant enzymes, with GSH-PX and GR down-regulation, and CAT and SOD significantly upregulation. Based on these data, we tentatively concluded that the oxidant stress was induced by MCs, and caused the different response of the antioxidant enzyme genes.
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Affiliation(s)
- Yuhua Sun
- Key Laboratory of Animal Development, Genetics and Reproduction of Education Ministry, College of Fisheries, Huazhong Agricultural University, Wuhan 430070, People's Republic of China
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Pegram RA, Nichols T, Etheridge S, Humpage A, LeBlanc S, Love A, Neilan B, Pflugmacher S, Runnegar M, Thacker R. Cyanotoxins Workgroup report. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2008; 619:317-81. [PMID: 18461775 DOI: 10.1007/978-0-387-75865-7_15] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
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27
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Gaudin J, Huet S, Jarry G, Fessard V. In vivo DNA damage induced by the cyanotoxin microcystin-LR: comparison of intra-peritoneal and oral administrations by use of the comet assay. Mutat Res 2007; 652:65-71. [PMID: 18282792 DOI: 10.1016/j.mrgentox.2007.10.024] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2006] [Revised: 05/10/2007] [Accepted: 10/15/2007] [Indexed: 12/13/2022]
Abstract
Microcystin-LR (MC-LR), involved in human and animal poisonings by cyanobacteria, has been shown to be both a potent tumour promoter in rat liver and an inhibitor of serine/threonine protein phosphatases, specifically PP1 and PP2A. The research on the genotoxic potential of MC-LR counts only few in vivo studies. In order to determine the target organs for DNA-damage induction by MC-LR, the single-cell gel electrophoresis (SCGE) or comet assay was performed in mice. Following a single oral administration of 2 and 4mg/kg bw of MC-LR, a statistically significant induction of DNA damage in blood cells was obtained after 3h. However, after an intra-peritoneal injection (ip), DNA lesions were mainly induced in the liver, but were also reported in the kidney, the intestine and the colon. The sensitivity of the ip route compared to the oral route suggested a difference in the bio-disponibility of the toxin. In any case, DNA damage was induced by MC-LR irrespective of the administration route. Among the target organs, the DNA damage induced in the intestinal tissues (ileum and colon) may contribute to an increased cancer risk.
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Affiliation(s)
- Julien Gaudin
- Agence Française de Sécurité Sanitaire des Aliments, Laboratoire d'Etudes et de Recherches sur les Médicaments Vétérinaires et les Désinfectants, Unité de Toxicologie Génétique des Contaminants Alimentaires, Fougères, France.
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